Simulated biomechanical performance of morphologically disparate ant mandibles under bite loading.

Insects evolved various modifications to their mouthparts, allowing for a broad exploration of feeding modes. In ants, workers perform non-reproductive tasks like excavation, food processing, and juvenile care, relying heavily on their mandibles. Given the importance of biting for ant workers and the significant mandible morphological diversity across species, it is essential to understand how mandible shape influences its mechanical responses to bite loading. We employed Finite Element Analysis to simulate biting scenarios on mandible volumetric models from 25 ant species classified in different feeding habits. We hypothesize that mandibles of predatory ants, especially trap-jaw ants, would perform better than mandibles of omnivorous species due to their necessity to subdue living prey. We defined simulations to allow only variation in mandible morphology between specimens. Our results demonstrated interspecific differences in mandible mechanical responses to biting loading. However, we found no evident differences in biting performance between the predatory and the remaining ants, and trap-jaw mandibles did not show lower stress levels than other mandibles under bite loading. These results suggest that ant feeding habit is not a robust predictor of mandible biting performance, a possible consequence of mandibles being employed as versatile tools to perform several tasks.

Optimizing structural and mechanical properties of cryogel scaffolds for use in prostate cancer cell culturing.

Prostate cancer (PCa) currently is the second most diagnosed cancer in men and the second most cause of cancer death after lung cancer in Western societies. This sets the necessity of modelling prostatic disorders to optimize a therapy against them. The conventional approach to investigating prostatic diseases is based on two-dimensional (2D) cell culturing. This method, however, does not provide a three-dimensional (3D) environment, therefore impeding a satisfying simulation of the prostate gland in which the PCa cells proliferate. Cryogel scaffolds represent a valid alternative to 2D culturing systems for studying the normal and pathological behavior of the prostate cells thanks to their 3D pore architecture that reflects more closely the physiological environment in which PCa cells develop. In this work the 3D morphology of three potential scaffolds for PCa cell culturing was investigated by means of synchrotron X-ray computed micro tomography (SXCµT) fitting the according requirements of high spatial resolution, 3D imaging capability and low dose requirements very well. In combination with mechanical tests, the results allowed identifying an optimal cryogel architecture, meeting the needs for a well-suited scaffold to be used for 3D PCa cell culture applications. The selected cryogel was then used for culturing prostatic lymph node metastasis (LNCaP) cells and subsequently, the presence of multi-cellular tumor spheroids inside the matrix was demonstrated again by using SXCµT.

17 beta-Oestradiol, androstenedione and inhibin levels in fluid from individual follicles of normal and polycystic ovaries, and in ovaries from androgen treated female to male transsexuals.

OBJECTIVE: The aim was to monitor carefully follicular growth arrest in polycystic ovaries by assay of hormones in individual follicles. DESIGN AND PATIENTS: Fluid from follicles less than or equal to 10 mm was obtained from ovaries of 16 regularly cycling women between days 1 and 12 of the follicular phase (controls, n = 120 follicles), polycystic ovaries of five women with polycystic ovary syndrome (n = 43), and polycystic ovaries from 14 long-term testosterone treated female to male transsexuals (n = 120). MEASUREMENTS: Fluid was assayed for oestradiol, androstenedione, and immunoactive inhibin. Luteinizing hormone, follicle-stimulating hormone, and testosterone levels were estimated in serum. RESULTS: Median serum LH was lower in transsexuals than in controls (P less than 0.05), and in polycystic ovary syndrome (P less than 0.01). Median serum testosterone was not significantly different between polycystic ovary syndrome and transsexuals, and was elevated in both groups as compared to controls (P less than 0.01). Oestradiol was present in all follicles obtained from polycystic ovaries of polycystic and transsexual patients, in which no follicle greater than 10 mm could be detected. In the three groups, between-patient differences in mean oestradiol, androstenedione, inhibin, and androstenedione/oestradiol ratio were significantly larger than expected in view of the variation between follicles within individuals. Taking into account this between-patient difference, no significant differences could be established between the three groups for all endocrine parameters. The percentage of presumed healthy follicles (androstenedione/oestradiol ratio less than or equal to 4) was 12% in controls, 17% in polycystics, and 14% in transsexuals, and was not significantly different between groups. CONCLUSIONS: The results may indicate that (1) abnormally high circulating androgen concentrations with or without elevated LH levels disturb the process of selection, and could therefore play a role in the pathogenesis of polycystic ovaries; (2) in polycystic ovaries from polycystic ovary syndrome and transsexual patients, aromatase activity is present in vivo in small antral follicles, and the proportion of presumed healthy follicles is not different from that encountered in normal ovaries; (3) oestradiol levels are not different between non-dominant follicles of normal and polycystic ovaries, suggesting that only enhancement of aromatase activity by FSH may be disrupted in polycystic ovaries, (4) because androstenedione levels are not different comparing follicles of normal and polycystic ovaries, hyperandrogenaemia in the syndrome seems to originate from the abnormally high number of cystic atretic follicles generally observed in polycystic ovaries; (5) marked variation in the endocrine follicular microenvironment within and between-women precludes pooling fluid from several follicles.