ABSTRACT
This study aimed to assess the delamination detection in FMLs via the finite element (FE) simulations of Lamb wave propagation. An FE model of an FML specimen with [Al/902/Al/902/Al] layup was developed. Delamination damage of 10 and 25 mm diameters was induced between different layers of the FML specimen. The fundamental antisymmetric Lamb wave mode (A0) at 60 kHz and the fundamental symmetric Lamb wave mode (S0) at the frequency of 206 kHz were propagated on the developed FE models. The Lamb wave phase velocity was obtained from the FE models and compared with those obtained from the Lamb wave propagation tests. The sensitivity of the A0 and S0 Lamb wave modes to the delamination and its diameter were examined. The inverse Lamb wave propagation problem was then solved, and the elastic modulus of the FML specimen was estimated in the intact and delamination regions. It was observed that the phase velocity of the S0 Lamb wave mode had a higher sensitivity to the delamination damage compared to that of the A0 Lamb wave mode. The phase velocity of the A0 Lamb wave mode was more sensitive to the delamination diameter. The capability of the proposed simulated Lamb wave propagation method as a virtual lab for detecting delamination in the FMLs was confirmed.
ABSTRACT
AIM: The follicular size has been considered for years as an index for oocyte maturity in stimulated ovulation cycles so that the time of initiating human chorionic gonadotropin (HCG) has been formerly determined by the ultrasonography measurement of larger follicles. The other studies have demonstrated that there was no significant difference between fertility of oocytes aspirated from follicles with various sizes. The objective of this study to explore the associations among the size and volume of extracted follicles at the time of oocyte collection with the rate of collection, oocyte maturity, and oocyte competence in the intracytoplasmic sperm injection (ICSI) therapeutic cycles. METHODS: This prospective study was performed on 412 stimulated ovulation cycles of 340 patients visiting the infertility center of Tehran Mirzakouchakkhan Hospital from September 2011 to February 2013, so that a total of 2324 follicles were investigated. The follicular diameter and fluid volume were measured then the follicles were classified into four groups regarding the aforesaid spatial dimensions. The association among the size and volume of follicles with the probability of oocytes collection, oocytes maturity, fertility competence, cleavage rate, and embryo quality was assessed. RESULTS: The majority of follicles (38%) were categorized in the group C with the follicle diameter of 16-20 mm and volume of 1-3 mm3. No significant difference was observed between these four follicle groups in terms of oocyte collection rate. There was a significant difference (P<0.05) between the group A (diameter>21 mm; volume>5 mm3) and group D (diameter<12 mm; volume≤1 mm3) regarding oocyte maturity and collection rate of metaphase II (MII) oocyte. Conversely, this difference was not significant between groups A, B (diameter=16-20 mm; volume=3-5 mm3), and C (diameter=12-15 mm; volume=1-3 mm3). The fertility rate of oocytes aspirated from small follicles was 55%, which is significantly lower than the fertility rate of oocytes obtained from follicles larger than 12 mm and volume of more than 1 mm3. However, the oocytes aspirated from smaller follicles continue to cleaved, and the quality of embryos did not significantly differ from that embryos cultivated from larger follicles. CONCLUSION: This study showed that the size of follicles and the oocytes maturity in stimulated ovaries are not considerably associated, thus might be independent factors. The development competence of oocytes from smaller follicles was similar to oocytes aspirated from larger follicles. Thus follicles smaller than 12 mm in size and 1 mm3 in volume should be also aspirated. Moreover, this study suggests initiating HCG at the phase with follicles equal to or larger than 16 mm to save time and expense for the patient.
