Abstract
Planets are known to grow out of a star-encircling disk of the gas and dust inherited from an interstellar cloud; their formation is thought to begin with coagulation of submicron dust ...grains into aggregates, the first foundational stage of planet formation. However, with nanoscale and submicron solids unobservable directly in the interstellar medium (ISM) and protoplanetary disks, how dust grains grow is unclear, as are the morphology and structure of interstellar grains and the whereabouts and form of “missing iron.” Here we show an elementary composite binary in 3D sub-10 nm detail—and the alignments of its two subunits and nanoinclusions and a population of elongated composite grains locked in a primitive cosmic dust particle—noninvasively uncovered with phase-contrast X-ray nanotomography. The binary comprises a pair of oblate, quasi-spheroidal grains whose alignment and shape meet the astrophysical constraints on polarizing interstellar grains. Each member of the pair contains a high-density core of octahedral nanocrystals whose twin relationship is consistent with the magnetite’s diagnostic property at low temperatures, with a mantle exhibiting nanoscale heterogeneities, rounded edges, and pitted surfaces. This elongated binary evidently formed from an axially aligned collision of the two similar composite grains whose core–mantle structure and density gradients are consistent with interstellar processes and astronomical evidence for differential depletion. Our findings suggest that the ISM is threaded with dust grains containing preferentially oriented iron-rich magnetic nanocrystals that hold answers to astronomical problems from dust evolution, grain alignment, and the structure of magnetic fields to planetesimal growth.
We show that using infiltration of ZnO metal oxide can be useful for high resolution imaging of biological samples in electron and X-ray microscopy. The method is compatible with standard fixation ...techniques that leave the sample dry, such as finishing with super critical CO
drying, or simple vacuum drying up to 95 °C. We demonstrate this technique can be applied on tooth and brain tissue samples. We also show that high resolution X-ray tomography can be performed on biological systems using Zn K edge (1s) absorption to enhance internal structures, and obtained the first nanoscale 10 KeV X-ray absorption images of the interior regions of a tooth.
Unlocking the 3‐D structure and properties of intact chondritic porous interplanetary dust particles (IDPs) in nanoscale detail is challenging, which is also complicated by atmospheric entry heating, ...but is important for advancing our understanding of the formation and origins of IDPs and planetary bodies as well as dust and ice agglomeration in the outer protoplanetary disk. Here, we show that indigenous pores, pristine grains, and thermal alteration products throughout intact particles can be noninvasively visualized and distinguished morphologically and microstructurally in 3‐D detail down to ~10 nm by exploiting phase contrast X‐ray nanotomography. We have uncovered the surprisingly intricate, submicron, and nanoscale pore structures of a ~10‐μm‐long porous IDP, consisting of two types of voids that are interconnected in 3‐D space. One is morphologically primitive and mostly submicron‐sized intergranular voids that are ubiquitous; the other is morphologically advanced and well‐defined intragranular nanoholes that run through the approximate centers of ~0.3 μm or lower submicron hollow grains. The distinct hollow grains exhibit complex 3‐D morphologies but in 2‐D projections resemble typical organic hollow globules observed by transmission electron microscopy. The particle, with its outer region characterized by rough vesicular structures due to thermal alteration, has turned out to be an inherently fragile and intricately submicron‐ and nanoporous aggregate of the sub‐μm grains or grain clumps that are delicately bound together frequently with little grain‐to‐grain contact in 3‐D space.
•Meat quality parameters of the wild and farm-raised fallow deer were analyzed.•Our findings may suggest that meat from wild fallow deer has more desirable properties.•Further research is needed to ...validate this hypothesis.
The objective of the present study was to determine the chemical composition as well as the physicochemical and sensory properties of meat (Longissimus lumborum muscle) from wild fallow deer (Dama dama L.) bucks shot during a hunt in forests of north-eastern Poland (n=11) and farm-raised fallow deer bucks (n=14) slaughtered on a farm in north-eastern Poland. It was found that the number of samples with pHu higher than 6.0 accounted for 57% of all samples collected in the group of farmed-raised fallow deer. Meat samples with pH>6.0 were not taken into consideration while evaluating meat quality. Meat from wild fallow deer, compared with farmed animals, was characterized by a higher (P≤0.01) content of fat, a higher (P≤0.01) calorific value, a more desirable fatty acid profile, including higher (P≤0.05) concentrations of unsaturated fatty acids, lower (P≤0.01) average pHu values, lower (P≤0.05) lightness (L*) and higher (P≤0.01) color saturation resulting from a higher contribution of redness (P≤0.01) and yellowness (P>0.05). Meat from wild fallow deer received also higher scores for aroma desirability (P≤0.01), taste desirability (P≤0.05), juiciness (P≤0.05) and lower (P≤0.01) scores for tenderness.
The objective of the present study was to determine the chemical composition as well as the physicochemical and sensory properties of meat (M. longissimus dorsi) from roe deer (Capreolus capreolus ...L.) does (n=26) and bucks (n=16) hunter-harvested in the forests of north-eastern Poland. It was found that meat from female roe deer, in comparison with meat from male roe deer, had higher (P≤0.01) content of dry matter, total protein and fat. The water extracts of meat from does also contained more (P≤0.01) total nitrogen and non-protein nitrogen. An analysis of the fatty acid profile revealed that the muscles of male roe deer had higher (P≤0.01) concentrations of the following fatty acids: C14:0, C15:0, C18:0, C20:0, C18:2 and C18:3, and higher (P≤0.01) total content of polyunsaturated fatty acids, while the muscles of female roe deer had higher (P≤0.01) levels of C17:1 and C18:1 and higher (P≤0.01) total content of monounsaturated and unsaturated fatty acids. Meat from does was also characterized by higher (P≤0.01) drip loss and, as shown by a sensory evaluation, higher (P≤0.01) juiciness. No significant differences were found between males and females with respect to the average scores for meat tenderness, but meat from bucks was characterized by a higher (P≤0.05) value of shear force.
In the 1970s, Joan Birman and Hugh Hilden wrote several papers on the problem of relating the mapping class group of a surface to that of a covering space. Their results provide a bridge between the ...theories of mapping class groups and braid groups. We survey the work of Birman and Hilden, give an overview of the subsequent developments, and discuss open questions and new directions.
This paper presents the design of a robot-based detector manipulator for microdiffraction applications with a hard X-ray nanoprobe instrument system being constructed at the Advanced Photon Source ...(APS) for the Center for Nanoscale Materials (CNM) being constructed at Argonne National Laboratory (ANL). Applications for detectors weighing from 1.5 to 100
kg were discussed in three configurations.
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