Nitrogen Fixation and Translocation in Sugarcane

World sugarcane production is increasing rapidly as a biofuel. In some areas in Brazil, sugarcane has been grown continually over very long periods without N fertiliser inputs. Therefore, the occurrence of N fixation has been suspected. However, quantitative studies seeking to identify the N~2~ fixation sites in the plant and to record the translocation of fixed N around the plant have not yet established. A ^15^N~2~ gas tracer experiment was conducted using young sugarcane plants to investigate the sites of N~2~ fixation and also to explore the possibility of translocation of the fixed N among the plant's major organs. Young sugarcane plants (_Saccharum officinarum_ L.) about 40 cm high and some 14 days after sprouting from a stem cutting were exposed to ^15^N~2~ labeled air in a 500 mL plastic cylinder for 7 days. Following the 7-day ^15^N~2~ feeding, some plants were potted and grown on in normal air for a further chase period. The incorporation of ^15^N into the shoot, roots, and stem cutting was analysed at day-3, and day-7 of the labeling period and at day-14, and day-21 during the chase period. After 3 days of ^15^N~2~ feeding, the % of N derived from the ^15^N labeled air in the shoot, roots and stem cutting were 0.027%, 2.22% and 0.271%, respectively. The roots showed the highest N fixing activity followed by the stem cutting, while the incorporation of ^15^N into the shoot was very low. After 21 days about a half of the N originating in the stem cutting had been transported to the shoot and the roots. However, the ^15^N fixed either in the roots or in the stem cutting remained in the original parts and was not appreciably transported to the shoot

Laboratory-based X-ray phase-imaging scanner using Talbot-Lau interferometer for non-destructive testing

An X-ray Talbot-Lau interferometer scanning setup consisting of three transmission gratings, a laboratory-based X-ray source that emits X-rays vertically, and an image detector on the top has been developed for the application of X-ray phase imaging to moving objects that cannot be tested clearly with conventional absorption contrast. The grating-based X-ray phase imaging method usually employs a phase-stepping (or fringe-scanning) technique by displacing one of the gratings step-by-step while the object stays still. Since this approach is not compatible with a scanner-type application for moving objects, we have developed a new algorithm for achieving the function of phase-stepping without grating displacement. By analyzing the movie of the moiré pattern as the object moves across the field of view, we obtain the absorption, differential phase, and visibility images. The feasibility of the X-ray phase imaging scanner has been successfully demonstrated for a long sample moving at 5 mm/s. This achievement is a breakthrough for the practical industrial application of X-ray phase imaging for screening objects carried on belt-conveyers such as those in factories

Development of an Array of Compound Refractive Lenses for Sub-Pixel Resolution, Large Field of View, and Time-Saving in Scanning Hard X-ray Microscopy

A two-dimensional array of compound refractive lenses (2D array of CRLs) designed for hard X-ray imaging with a 3.5 mm$^{2}$ large field of view is presented. The array of CRLs consists of 2D polymer biconcave parabolic 34 × 34 multi-lenses fabricated via deep X-ray lithography. The developed refractive multi-lens array was applied for sub-pixel resolution scanning transmission X–ray microscopy; a raster scan with only 55 × 55 steps provides a 3.5 megapixel image. The optical element was experimentally characterized at the Diamond Light Source at 34 keV. An array of point foci with a 55 µm period and an average size of ca. 2.1 µm × 3.6 µm was achieved. In comparison with the conventional scanning transmission microscopy using one CRL, sub-pixel resolution scanning transmission hard X-ray microscopy enables a large field of view and short scanning time while keeping the high spatial resolution

Parabolic gratings enhance the X-ray sensitivity of Talbot interferograms

In grating-based X-ray Talbot interferometry, the wave nature of X-ray radiation is exploited to generate phase contrast images of objects that do not generate sufficient contrast in conventional X-ray imaging relying on X-ray absorption. The phase sensitivity of this interferometric technique is proportional to the interferometer length and inversely proportional to the period of gratings. However, the limited spatial coherency of X-rays limits the maximum interferometer length, and the ability to obtain smaller-period gratings is limited by the manufacturing process. Here, we propose a new optical configuration that employs a combination of a converging parabolic micro-lens array and a diverging micro-lens array, instead of a binary phase grating. Without changing the grating period or the interferometer length, the phase signal is enhanced because the beam deflection by a sample is amplified through the array of converging-diverging micro-lens pairs. We demonstrate that the differential phase signal detected by our proposed set-up is twice that of a Talbot interferometer, using the same binary absorption grating, and with the same overall inter-grating distance