Analysis of the optical properties of the silvery spots on the wings of the Gulf Fritillary, Dione vanillae

The ventral face of the wings of the butterfly Dione vanillae is covered with bright and shiny silvery spots. These areas contain densely packed ground- and coverscales with a bright metallic appearance reflecting more than 50% of light uniformly over the visible range. Our analysis shows that this optically attractive feature is caused by the inner microstructure of the scales located in these areas. Electron microscopy of cross sections through the scales shows that upper and lower lamina, supporting trabeculae, and topping ridges can be approximated by a ‘circus tent’-like geometry. By simulating its optical properties, we show that a moderate disorder of this geometry is important for the uniform reflection of light resulting in the silvery appearance

Internal inspection of semi-transparent objects by digital holographic micro-tomography

The combined use of digital holographic microscopy and computer tomography, here named digital holographic micro-tomography, is used to examine the interior of transparent channels. The proposed method is used to identify internal obstacles inside of transparent troughs having slightly different refractive index. The method is based in the acquisition of a set of digital holograms of the specimen whereas it is axially rotated from 0° to 180°. The phase differences retrieved from the obtained holograms are the inputs to a computerised axial tomography procedure. The technique has been numerically modelled in order to find the optimal tomographic conditions and also to realise the minimum difference of refractive index the method could detect. The obtained results show the feasibility of the proposed method for the non-destructive evaluation of transparent micro-objects.Fil: Monroy Ramirez, F. A.. Universidad Nacional de Colombia; ColombiaFil: Dolinko, Andrés Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Garcia Sucerquia, J.. Universidad Nacional de Colombia; Colombi

Responses to fertility treatment among patients with cancer: a retrospective cohort study

Abstract Background Cancer treatments have significant negative impacts on female fertility, but the impact of cancer itself on fertility remains to be clarified. While some studies have shown that compared with healthy women, those with cancer require higher doses of gonadotropins resulting in decreased oocyte yields, others have shown comparable oocyte yields between the two groups. The purpose of this study is to evaluate whether there is an association between any cancer and/or type of cancer, and response to ovarian stimulation for egg and embryo banking. Methods In this retrospective cohort study, ovarian stimulation cycles performed from June 2007 through October 2014 at a single academic medical center were reviewed to identify those undertaken for women with cancer undergoing fertility preservation (n = 147) or women with no cancer undergoing their first cycle due to male factor infertility (n = 664). Of the 147 women undergoing fertility preservation, 105 had local cancer (Stage I-III solid malignancies) and 42 had systemic cancer (hematologic or Stage IV solid malignancies). Response to ovarian stimulation was compared among these two groups and women with no cancer. Results Adjusting for age and BMI, women with systemic cancer had lower baseline antral follicle counts (AFC) than women with no cancer or local cancer. Women with systemic cancer required higher doses of FSH than women with no cancer or local cancer, and they had higher oocyte to AFC ratios than women with no cancer or local cancer, but greater odds of cycle cancellation as compared to women with no cancer or local cancer. No significant differences were observed among the three groups for duration of stimulation, number of oocytes and mature oocytes retrieved, or number of embryos created. Conclusions Women with cancer achieve similar oocyte and embryo yields as women with no cancer, although those with systemic cancer require higher FSH doses and are at greater risk of cycle cancellation