Objective To investigate the dependency of thermal expansion coefficient of DNA adsorption film on environmental conditions. Methods By treating DNA adsorption film as a macroscopic continuum film with prestrain, an equivalent composite beam model of DNA film-substrate was established to calculate the deflection of DNA-microcantilever beam under temperature loading. By adopting Parsegian’s empirical potential which described the mesoscopic free energy of DNA adsorption film, the DNA liquid crystal-substrate multi-scale deflection model, the thought experiment method and the equivalent deformation method were combined to establish the trans-scale relationship between the microstructure of DNA adsorption film and its macro-scale mechanical properties. The thermal expansion coefficient of DNA adsorption film was predicted. ResultsGiven the ionic strength, the thermal expansion coefficient of double-stranded DNA adsorption film ranged from 0.3×10-4/K to 8.05×10-4/K, and that of single-stranded DNA adsorption film ranged from 1.28×10-4/K to 9.33×10-4/K. Conclusions As a leading role in the competition of micro-interactions, the change of configurational entropy determines the dependency of thermal expansion coefficient of DNA adsorption film on environmental conditions; the thermal expansion coefficient of DNA adsorption film decreases with the increase of temperature or ion concentration or DNA packing density. These results are useful for gene detection and its regulation, and provide reference for the evaluation of tissue organ performance in tissue engineering.

Objective To investigate the influence of the microscale attractive interaction on the elastic properties of DNA film in multivalent ion solutions. Methods Kornyshev's electrostatic zipper model was employed to describe the interaction energy between the DNA strands. The thought experiment method and macroscopic continuum bar model were combined to predict the stress-strain relationship, prestress, and elastic modulus of the DNA biofilm.Results Given the packing conditions, the DNA film exhibited a tensile prestress and negative elastic modulus. The prestress of the DNA biofilm ranged from -1.52 MPa to 1.17 MPa, and its elastic modulus ranged from -4.2 MPa to 64 MPa. Conclusions In contrast with monovalent solutions, the microscopic attractive interactions in multivalent solutions caused the elastic properties of the DNA film to exhibit a non-monotonous relationship with the variation in the packing density and salt concentration. The tensile elastic properties were significantly different from the compressive ones, and the tensile/compressive prestress as well as the positive/negative elastic modulus transformed each other. These results can contribute to understanding the mechanism of viral replication and provide references for gene detection and gene therapy.

OBJECTIVE: To determine the sperm-zona pellucida (ZP) binding and ZP-induced acrosome reaction in patients with unexplained infertility, and to discuss the relationship between ZP-induced acrosome reaction and fertilization rate. METHODS: We compared the fertilization rate and good embryo rate in patients with unexplained infertility after fertilization in 2 ways. Based on the causes of infertility, patients were divided into an unexplained infertility group (Group A) and a pure female tubal factor group (Group B). Oocytes which were obtained by super ovulation from 25 patients with unexplained infertility were randomly divided into 2 groups with conventional in vitro fertilization (IVF) (Group A1) and intracytoplasmic sperm injection (ICSI) fertilization (Group A2). The pure female tubal factor group (Group B) had conventional IVF. We conducted sperm-ZP binding and ZP-induced acrosome reaction experiments with 2 groups of men's sperms separately. We compared the number of sperm-egg binding and ZP-induced acrosome reaction rate and discussed the relationship between the ZP-induced acrosome reaction and fertilization rate, and also the fertilization rate, good embryo rate and pregnancy rate in patients with unexplained infertility after fertilization in 2 ways. RESULTS: The average number of sperm-egg binding (78.29 ± 16.31) and the ZP-induced acrosome reaction rate (55.87 ± 27.69) % in Group A were lower than those of Group B [94.63 ± 6.72, (82.53 ± 17.99)%]. The difference between the average number of sperm-egg binding and the ZP-induced acrosome reaction was significant (P <0.01). The fertilization rate of Group A1 was significantly lower than that of Group B and Group A2 (P <0.01). But there was no significant difference in the good embryo rate among the 3 groups. There was no significant difference between Group A2 and B in fertilization rate and good embryo rate (P <0.05). There was no significant difference in pregnancy rate between Group A and B (P <0.05). Fertilization rate and the rate of acrosome reaction had marked positive correlation with statistical significance (r =0.932, P <0.01). CONCLUSION ZP binding and ZP-induced acrosome reaction are very important experiments in sperm function test for patients with unexplained infertility. It can not only effectively avoid no embryo transferring due to complete failure of fertilization but also get a desirable outcome of pregnancy using half-ICSI fertilization in patients with unexplained infertility.
Acrosome Reaction ; Embryo Transfer ; Female ; Fertilization in Vitro ; Humans ; Infertility ; etiology ; therapy ; Male ; Oocytes ; physiology ; Ovulation Induction ; Sperm Injections, Intracytoplasmic ; Sperm-Ovum Interactions ; physiology ; Treatment Outcome ; Zona Pellucida ; physiology

OBJECTIVE: To explore the different effect of short 7-day gonadotropin releasing hormone agonist (GnRHa) protocol and GnRHa long protocol on the insulin-like growth factor II(IGF-II) and insulin-like growth factor binding protein-4 (IGFBP-4) levels in follicular fluid. METHODS: Eighty-eight infertile patients due to tubal factors were included in this study. They were randomly divided into a short 7-day GnRHa protocol group and a GnRHa long protocol group (n = 44). Follicular fluid was obtained from dominant follicles during oocyte retrieval. Levels of IGF-II and IGFBP-4 in the follicular fluid were detected by radioimmunoassay and enzyme-linked immunosorbent assay respectively. RESULTS: Duration of controlled ovarian stimulation was significantly shorter and the injected dosages of gonadotropin were significantly lower in the short 7-day protocol group. The differences in serum levels of estradiol and estradiol per mature follicle on the day of human chorionic gonadotropin injection between the two groups were not significant. The concentrations of IGF-II and IGFBP-4 in the follicular fluid of the short 7-day protocol group were significantly lower,while the difference of the ratio of IGF-II/IGFBP-4 between the two groups was not significant. Linear correlation analysis showed that IGF-II level in the follicular fluid was positively correlated to the total dose of gonadotropin. CONCLUSION The short 7-day and long GnRHa protocols may affect the concentrations of IGF-II and IGFBP-4 in the follicular fluid. However, changes of IGF-II and IGFBP-4 concentrations do not contribute to different clinical outcomes.
Embryo Transfer ; Female ; Fertilization in Vitro ; methods ; Follicular Fluid ; chemistry ; Gonadotropin-Releasing Hormone ; administration & dosage ; agonists ; Humans ; Insulin-Like Growth Factor Binding Protein 4 ; analysis ; Insulin-Like Growth Factor II ; analysis ; Ovulation Induction ; methods