ABSTRACT
Objective To establish a comprehensive method combining physical model experiment and numerical simulation for studying airflow state of upper respiratory tract. Methods Based on CT medical images published online, a three-dimensional (3D) model of human upper respiratory tract was reconstructed. Based on 3D printing technology, an experimental model of the upper respiratory tract was established and the flow process of respiration was measured. A numerical simulation model was created based on the meshing of upper respiratory tract model and the turbulent Realizable k-ε model. Results Firstly, the result of numerical simulation was compared with the experimental conditions, and good agreement was achieved. The numerical simulation results showed that the airflow in respiratory process was in a parabolic shape; the distribution of flow field, pressure on wall and vortex structure were different between inspiratory and expiratory phases; there were air residues in the upper and lower nasal passages during the respiratory exchange process. In addition, the effects of airflow on physiological environment of the upper respiratory tract were preliminarily analyzed through the steak line, pressure field and vortex structure distribution. Conclusions The method proposed in this paper has the characteristics of pertinence, rapidity and accuracy, which gives full play to the advantages of reliable physical experiments and fine numerical simulation, and is applicable for studying different problems of the upper respiratory tract in different cases, with a high value for personalized diagnosis and treatment in clinic.
ABSTRACT
Human breast milk contains a good balance of nutrients.In recent years,researchers have found that it contains not only abundant nutrients,but also different active components,and MicroRNAs (miRNA) are included.MiRNA are endogenous non-coding RNA,consisting of 21 to 25 nucleotides in length.They play an important role in regulating a variety of biological processes.In the miRNA confirmed in human breast milk,let-7、miRNA-30b and miRNA-378 are highly expressed and researches have already demonstrated that these miRNA are participating in the regulation of adipocytes differentiation,lipid accumulation and sugar and lipid metabolism.
ABSTRACT
Objective To explore the expression levels of immune-related microRNA-146b (miR-146b),microRNA-155 (miR-155) and microRNA-30b(miR-30b) in human breast milk and its relationship with maternal and infant's health.Methods One hundred and thirty-four mothers and their infants from obstetrical department were recruited in the study after delivery.The subjects were divided into 2 groups,breast feeding group(n =86) and formula-feeding group(n =48),and were followed up 3 months after delivery.Breast milk samples were collected at 2-5 days after delivery(colostrum) and 3 months after delivery(mature milk).The expression levels of microRNAs in milk samples were detected by real-time PCR.The relationship between levels of microRNAs and maternal and infant-related factors was analyzed.Results 1.MiR-146b,miR-155 and miR-30b expressions were abundant both in human colostrums (5.950 ± 0.823,3.899 ± 0.920,4.057 ± 0.604) and mature milk (4.840 ± 0.805,2.128 ± 0.969,4.929 ± 0.566).The levels of miR-146b and miR-155 were higher in colostrum than that of mature milk (t =7.716,10.215,all P ＜ 0.01),while the level of miR-30b was higher in mature milk than that of colostrums(t =-8.626,P ＜ 0.0l).2.Additionally,the level of miR-30b was negatively correlated with maternal pre-pregnancy body mass index (r =-0.298,P ＜ 0.01).3.The levels of miR-146b and miR-30b were higher in mothers giving birth by vaginal delivery than those who underwent cesarean section(t =2.356,3.108,all P ＜0.05).4.The levels of miR-146b and miR-155 were higher in colostrum-fed girls than boys (t =-2.204,-2.985,all P ＜ 0.05).5.The level of miR-146b in mature milk was negatively correlated with 3-month-old infant' s Z score of body weight (r =-0.425,P ＜ 0.05) and body length (r =-0.569,P ＜ 0.01).6.During follow-up,the incidence of baby eczema in breast feeding group (8.82％,3/34 cases) was lower than that in formula milk feeding group(29.17％,14/48 cases) (x2 =5.012,P =0.025).Conclusions The levels of immunocompetent microRNAs in human milk are influenced by the lactation period,maternal prepregnancy body mass index,mode of delivery and infant sex.The immune-related microRNAs in human milk could be involved in the regulation of infant's immunity and growth.