Helium ion microscopy of Lepidoptera scales

Abstract

In this report, helium ion microscopy (HIM) is used to study the micro and nano-structures responsible for structural color in the wings of two species of Lepidotera from the Papilionidae family: Papilio ulysses (Blue Mountain Butterfly) and Parides sesostris (Emerald-patched Cattleheart). Electronic charging under the beam of uncoated scales from the wings of these butterflies is successfully neutralized, leading to images displaying a large depth-offield and a high level of surface detail, which would normally be obscured by traditional coating methods used for scanning electron microscopy (SEM). The images are compared to those from variable pressure SEM, demonstrating the superiority of HIM at high magnifications. In addition, the large depth-of-field capabilities of HIM are exploited through the creation of stereo pairs which allows the exploration of the third dimension. Furthermore, the extraction of quantitative height information which matches well with cross-sectional transmission electron microscopy (TEM) measurements from the literature is demonstrated.

Helium ion microscopy

“…6(a), a high resolution HIM image of a butterfly wing is presented. 70 The black ground scales of Papilio ulysses and other butterflies are imaged without any prior coating, which allows the smallest features to be identified. The large depth of field in HIM also makes it ideal for creating anaglyphs using different angles for imaging.…”

A new structural biomarker that quantifies and predicts changes in clot strength and quality in a model of progressive haemodilution

“…More fibrils within the image can be measured because more appear in focus, an advantage already applied to imaging other biological specimens. [22][23][24] Assessment of the arrangement of the clot microstructure was achieved by qualitative assessment of the images by visual inspection focusing on the general topography of the clot, and through quantification of the fibre widths in the clot. Fibre width were measured using the computer software program ImageJ® (Rasband WS, ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA) measuring widths of 100 different fibres at each dilution, using randomly generated x,y coordinates from within multiple fields of view.…”

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

“…The sponge-like surface implies a porous foamy structure, which is also indicated by the low density of 0.21 g·cm −3 of the sample. The edge resolution of the image in Figure 1b is around 15 nm, which was determined by the distance between 25% and 75% of the maximum intensity of a sharp edge [17]. porosity [9].…”