Inverted Hartmann mask for single-shot phase-contrast x-ray imaging of dynamic processes.

In this Letter, we present the application of the inverted Hartmann mask for time-resolved single-shot phase-contrast x-ray imaging. The inverted Hartmann mask is a periodic array of free-standing gold pillars. The array is manufactured by UV lithography and electroplating. Time-resolved measurements are performed for imaging of pulsed laser ablation in liquids using white-beam synchrotron radiation. The inverted Hartmann mask in combination with a single-shot imaging technique provides sufficient differential phase contrast even at very short exposure times. It can be effectively used for phase-contrast x-ray imaging of fast dynamic processes with temporal resolution on the millisecond scale.

Generalized pupil function of a compound X-ray refractive lens.

Quality of a refractive compound X-ray lens can be limited by imperfections in surfaces of unit lenses and stacking precision. In general case both the lens transmission and optical aberrations define properties of a beam in the lens exit plane; together they can be expressed in terms of the generalized pupil function. In this work we measure this function for a diamond single crystal compound refractive lens. Consequently, we apply the pupil function to evaluate the performance of the examined compound refractive X-ray lens. A number of practically important conclusions can be drawn from such analysis.

Development of structural colour in leaf beetles.

Structural colours in living organisms have been observed and analysed in a large number of species, however the study of how the micro- and nano-scopic natural structures responsible of such colourations develop has been largely ignored. Understanding the interplay between chemical composition, structural morphology on multiple length scales, and mechanical constraints requires a range of investigation tools able to capture the different aspects of natural hierarchical architectures. Here, we report a developmental study of the most widespread strategy for structural colouration in nature: the cuticular multilayer. In particular, we focus on the exoskeletal growth of the dock leaf beetle Gastrophysa viridula, capturing all aspects of its formation: the macroscopic growth is tracked via synchrotron microtomography, while the submicron features are revealed by electron microscopy and light spectroscopy combined with numerical modelling. In particular, we observe that the two main factors driving the formation of the colour-producing multilayers are the polymerization of melanin during the ecdysis and the change in the layer spacing during the sclerotisation of the cuticle. Our understanding of the exoskeleton formation provides a unique insight into the different processes involved during metamorphosis.

Extension of historical range of Betylobraconinae (Hymenoptera: Braconidae) into Palaearctic Region based on a Baltic amber fossil, and description of a new species of Mesocentrus Szépligeti from Papua New Guinea.

Two new species of the parasitic wasp genus Mesocentrus Szépligeti (Betylobraconinae) are described. One based on a new species from Papua New Guinea, the other the first Palaearctic member of the subfamily based on a 30+ mya, species from Baltic amber. The second species is illustrated using synchrotron X-ray microtomography. Whereas the extant Betylobraconinae are restricted to Australia, New Guinea and New Caledonia, their ancestral distribution is now known to have extended considerably further. A key to the four species of Mesocentrus known from Papua New Guinea is provided. Both species possess some putatively plesiomorphic characters absent in other extant Mesocentrus spp. The new extant species differs in having a considerably larger number of antennal segments and a less laterally depressed frons, while the extinct one has the clypeus separated from the face dorsally and strongly developed hypoclypeal depression. Availability of sequence data for this species enabled further analysis of the relationships of the subfamily, which we present in a phylogenetic analysis additionally including the release of a number of new sequences of related taxa.