Grazing-incidence small-angle X-ray scattering (GISAXS) coupled with computed tomography (CT) has enabled the visualization of the spatial distribution of nanostructures in thin films. 2D GISAXS images are obtained by scanning along the direction perpendicular to the X-ray beam at each rotation angle. Because the intensities at the q positions contain nanostructural information, the reconstructed CT images individually represent the spatial distributions of this information (e.g. size, shape, surface, characteristic length). These images are reconstructed from the intensities acquired at angular intervals over 180°, but the total measurement time is prolonged. This increase in the radiation dosage can cause damage to the sample. One way to reduce the overall measurement time is to perform a scanning GISAXS measurement along the direction perpendicular to the X-ray beam with a limited interval angle. Using filtered back-projection (FBP), CT images are reconstructed from sinograms with limited interval angles from 3 to 48° (FBP-CT images). However, these images are blurred and have a low image quality. In this study, to optimize the CT image quality, total variation (TV) regularization is introduced to minimize sinogram image noise and artifacts. It is proposed that the TV method can be applied to downsampling of sinograms in order to improve the CT images in comparison with the FBP-CT images.

Molybdenum oxides and sulfides on various low-cost high-surface-area supports are excellent catalysts for several industrially relevant reactions. The surface layer structure of these materials is, however, difficult to characterize due to small and disordered MoOx domains. Here, it is shown how X-ray total scattering can be applied to gain insights into the structure through differential pair distribution function (d-PDF) analysis, where the scattering signal from the support material is subtracted to obtain structural information on the supported structure. MoOx catalysts supported on alumina nanoparticles and on zeolites are investigated, and it is shown that the structure of the hydrated molybdenum oxide layer is closely related to that of disordered and polydisperse polyoxometalates. By analysing the PDFs with a large number of automatically generated cluster structures, which are constructed in an iterative manner from known polyoxometalate clusters, information is derived on the structural motifs in supported MoOx.

Because researchers do not understand the formation mechanism of cocrystals, the preparation of cocrystals is mostly done by trial and error. This study focuses on the cocrystal formation mechanism to improve the efficiency of cocrystal preparation.

By using small-angle neutron scattering (SANS) reinforced by scanning electron microscopy, the fine structure of catalysts for polymer electrolyte fuel cells has been investigated. The experimental data resulting from contrast variation with mixed light and heavy water (H2O/D2O) are well described by a core–shell model with fluctuations in concentration between water and Nafion.

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The design and assembly of two 3D-printed holders for high-throughput in meso in situ fixed-target crystallographic data collection are described.

Exact and approximate formulas for equatorial aberration of a continuous-scan Si strip detector are compared.

Neutron crystal structure analysis of hen egg-white lysozyme hydrogen/deuterium exchanged before crystallization were performed by the joint X-ray and neutron refinement. The differences in hydrogen/deuterium exchange behavior between this study and previous ones were observed.

The crystal structure of the organic pigment 2-monomethyl-quinacridone (Pigment Red 192, C21H14N2O2) was solved from X-ray powder diffraction data. The resulting average structure is described in space group Poverline 1, Z = 1 with the molecule on the inversion centre. The molecules are arranged in chains. The molecules, which have no inversion symmetry, show orientational head-to-tail disorder. In the average structure, the methyl group is disordered and found on both ends of the molecule with an occupancy of 0.5 each. The disorder and the local structure were investigated using various ordered structural models. All models were analysed by three approaches: Rietveld refinement, structure refinement to the pair distribution function (PDF) and lattice-energy minimization. All refinements converged well. The Rietveld refinement provided the average structure and gave no indication of a long-range ordering. The refinement to the PDF turned out to be very sensitive to small structural details, giving insight into the local structure. The lattice-energy minimizations revealed a significantly preferred local ordering of neighbouring molecules along the [0ar 11] direction. In conclusion, all methods indicate a statistical orientational disorder with a preferred parallel orientation of molecules in one direction. Additionally, electron diffraction revealed twinning and faint diffuse scattering.

In this work, the mechanism of solvent-mediated desolvation transformation of lenvatinib mesylate (LM) was investigated. Two new solid forms of LM, a dimethyl sulfoxide (DMSO) solvate and an unsolvated form defined as form D, were discovered and characterized using powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, polarized light microscopy and Raman spectroscopy. To investigate the thermodynamic mechanism of solvent-mediated desolvation transformation (SMDT) from LM DMSO solvate to form D, solubilities of LM DMSO solvate and form D in binary solvent mixtures of DMSO and water at different water volume fractions and temperatures (293.15–323.15 K) were measured and correlated by non-random two liquids model. The solubility data were used to evaluate the thermodynamic driving force of the SMDT process from DMSO solvate to form D and the effect of the activities of water and DMSO on the transformation process. Raman spectroscopy was used to monitor in situ the solid phase compositions during the SMDT process from LM DMSO solvate to form D while the solution concentration was measured by the gravimetric method. The overall desolvation transformation experiments demonstrated that the SMDT process was controlled by the nucleation and growth of form D. Moreover, effects of operating factors on the SMDT process were studied and the results illustrated that water activity in solution was the paramount parameter in the SMDT process. Finally, a new SMDT mechanism was suggested and discussed.

The crystal structure of the mineral malayaite has been studied by single-crystal X-ray diffraction at a temperature of 20 K and by calculation of its phonon dispersion using density functional perturbation theory. The X-ray diffraction data show first-order satellite diffraction maxima at positions q = 0.2606 (8)b*, that are absent at room temperature. The computed phonon dispersion indicates unstable modes associated with dynamic displacements of the Ca atoms. The largest-frequency modulus of these phonon instabilities is located close to a wavevector of q = 0.3b*. These results indicate that the malayaite crystal structure is incommensurately modulated by static displacement of the Ca atoms at low temperatures, caused by the softening of an optic phonon with Bg symmetry.

The crystal structure of malayaite, CaSnOSiO4, at T = 20 K has been refined, based on the presence of satellite reflections with a modulation vector of 0.26b*. The structural modulation is attributed to a soft optic phonon, dominated by motion of the Ca atoms.

The solvent-mediated desolvation process of newly discovered lenvatinib DMSO solvate to form II at different water volume fractions and temperatures was investigated. It is confirmed that the activity of water is the most important factor affecting the desolvation process: the desolvation process only occurs when the activity of water is greater than the activity of DMSO, and one new mechanism of solvent-mediated desolvation process was proposed.

The crystal structure of the nanocrystalline pigment mono­methyl-quinacridone was solved from X-ray powder data. The orientational disorder was investigated using Rietveld refinements, structure refinement to the pair-distribution function, and lattice-energy minimizations of various ordered structural models.

The synthesis, characterization and study of structures from a series of bi­phenyls substituted at positions 3, 3', 4 and 4' with groups connected to the bi­phenyl core through oxygen atoms are presented here. The molecular conformation is extensively studied both in the solid as well as in the liquid state, and the effect of different actors (such as packing and chain length) on the torsion angle between aromatic rings is analyzed.

A new ZnII metallocryptand is presented, with an unprecedented diflexure helix.

The crystal structure of Pseudomonas aeruginosa Fis is composed of an N-terminal flexible loop and a C-terminal helix–turn–helix motif.

White, who was a student at Columbian College from Accomack County, Va., died of pneumonia and complications from a mitral heart defect. When his coffin was unearthed, his identity was a deep mystery.

The post Remains of William Taylor White (1837-1852) donated to Smithsonian with his coffin and clothing appeared first on Smithsonian Insider.

About as thick as a standard dictionary, this turtle’s shell may have warded off attacks by the Titanoboa, thought to have been the world’s biggest snake, and by other, crocodile-like creatures living in its neighborhood 60 million years ago.

The post Newly discovered prehistoric turtle co-existed with world’s biggest snake appeared first on Smithsonian Insider.

Eric Silver of SAO is pursuing innovative and interdisciplinary uses of his technique for chemical imaging at the cellular level.

The post Technology developed for X-ray astronomy is being adapted to study cancer cells appeared first on Smithsonian Insider.

Scientists and local dive operators first noticed coral bleaching in the waters surrounding Isla Colon, in Panama’s Bocas del Toro province in July. Smithsonian staff scientist Nancy Knowlton and colleagues documented an extensive bleaching event in late September.

The post Coral bleaching event caused by warming ocean waters is documented in Panama appeared first on Smithsonian Insider.

The tiger reserves of Asia could support more than 10,000 wild tigers – three times the current number – if they are managed as large-scale […]

The post Tiger numbers could triple if large-scale landscapes are protected appeared first on Smithsonian Insider.

A. sediba was discovered in 2008 in the Malapa Cave at the Cradle of Humankind World Heritage Site located outside Johannesburg.

The post Skeletal casts of early hominin ancestor from Africa donated to National Museum of Natural History appeared first on Smithsonian Insider.

Tiny Antarctic marine creatures collected 100 years ago by British Royal Navy explorer Robert Falcon Scott are giving scientists new clues about polar environmental change.

The post Tiny creatures collected 100 years ago confirm accelerating carbon uptake in Antarctic Ocean appeared first on Smithsonian Insider.

Faced with insufficient time and inadequate library resources to tackle the problem on their own, they instead posted a catalog of specimen images to Facebook and turned to their network of colleagues for help.

The post Facebook friends help scientists quickly identify nearly 5,000 fish specimens collected in Guyana appeared first on Smithsonian Insider.

Smithsonian scientists have confirmed that chytridiomycosis, a rapidly spreading amphibian disease, has reached a site near Panama’s Darien region. This was the last area in the entire mountainous neotropics to be free of the disease. This is troubling news for the Panama Amphibian Rescue and Conservation Project, a consortium of nine U.S. and Panamanian institutions that aims to rescue 20 species of frogs in imminent danger of extinction.

The post Deadly amphibian disease detected in the last disease-free region of Central America appeared first on Smithsonian Insider.

A scientist from the Smithsonian Tropical Research Institute uses a pick to dislodge the fossil skull of an extinct toothed whale from sediments on the […]

The post Fossil skull of an extinct toothed whale excavated from Panamanian sediments appeared first on Smithsonian Insider.

New excavations in Indonesia and dating analyses by scientists at the Smithsonian and their colleagues show that modern humans never co-existed with Homo erectus.

The post Scientists show that modern humans never co-existed with <em>Homo erectus</em> appeared first on Smithsonian Insider.

Ecologists at the Smithsonian Environmental Research Center measure the growth rate of sedge grass in a brackish Chesapeake Bay marsh. Fed a diet rich in […]

The post SERC sedge grass experiment mimics predicted global-change scenario appeared first on Smithsonian Insider.

NASA's Kepler spacecraft has spotted a planet that alternately runs late and
early in its orbit because a second, "invisible" world is tugging on it.
This is the first definite detection of a previously unknown planet using
this method.

The post Invisible world “spotted” tugging on visible planet by Kepler spacecraft appeared first on Smithsonian Insider.

The fossil represents the youngest nodosaur ever discovered, and the only known specimen of a new genus and species of dinosaur that lived approximately 110 million years ago during the Early Cretaceous Era.

The post New dinosaur species named from hatchling fossil donated to National Museum of Natural History appeared first on Smithsonian Insider.

Our studies of the genetic relationships between these bees tells us that they originated in the Amazon about 22 million years ago and that they moved north into Central America before 3 million years ago.

The post Two closely related bee species discovered far apart in Panama and northern Colombia appeared first on Smithsonian Insider.

The first DNA barcoding survey of crustaceans living on samples of dead coral taken from the Indian, Pacific and Caribbean oceans suggests that the diversity of organisms living on the world’s coral reefs—one of the most endangered habitats on Earth—is seriously underestimated.

The post New DNA study suggests coral reef biodiversity is seriously underestimated appeared first on Smithsonian Insider.

16,000 square kilometers of giant panda habitat will likely be lost by the year 2080

The post Panda habitat to be lost, shifted by climate change appeared first on Smithsonian Insider.

New research by a team of astronomers found that planets smaller than Neptune are located around a wide variety of stars, including those with fewer heavy elements than the Sun.

The post Alien Earths may have formed in Universe earlier than expected appeared first on Smithsonian Insider.

Accumulations of drifting snow are the most plausible explanation for the presence of a number of puzzling alluvial fan deposits found inside large impact craters on Mars

The post Melting snow likely created fan deposits inside Martian craters, geologists say appeared first on Smithsonian Insider.

A July 12 news alert from NASA indicates a X1.4 class solar flare erupted from the center of the Sun, peaking July 12 at 12:52 P.M.

The post Coronal mass ejection from July 12 solar flare headed toward Earth; minor geomagnetic storm activity predicted appeared first on Smithsonian Insider.

They observed that no plugs were ever formed during mating trials, but instead, females exposed to many males produced the amorphous plugs during the egg-laying process.

The post Female spiders produce mating plugs to prevent unwanted sex from males appeared first on Smithsonian Insider.

A rare Longman’s beaked whale found stranded on the Hawaiian island of Maui in 2010 has scientists in Hawaii on the alert for a deadly disease known as morbillivirus which can lead to high mortality rates in dolphins and other marine mammals.

The post Rare whale beached in Hawaii infected with deadly marine-mammal virus appeared first on Smithsonian Insider.

Scientists at the University of Arizona and in California have completed the most challenging large astronomical mirror ever made.

The post First of seven mirrors completed for Giant Magellan Telescope appeared first on Smithsonian Insider.

New data from NASA's Chandra X-ray Observatory suggest a highly distorted supernova remnant (shown here) may contain the most recent black hole formed in the Milky Way galaxy.

The post Highly distorted supernova remnant seen by Chandra X-ray Observatory appeared first on Smithsonian Insider.

Among vertebrates few animals rival poison dart frogs for their vibrant electric blue, yellow, red and orange skin colors. Some experts have long believed these […]

The post Poison dart frog toxins best suited for deterring biting arthropods, research reveals appeared first on Smithsonian Insider.

Hot spots of mercury pollution in aquatic sediments and soils can contaminate local food webs and threaten ecosystems, but cleaning them up can be expensive […]

The post Toxicity of mercury hot spots can be reduced with application of activated carbon, researchers discover appeared first on Smithsonian Insider.

The name Panama is said to mean “abundance of fish.” Now a new study estimates that between 1950 and 2010, the amount of fish taken […]

The post Panamanian fish catch is vastly under-reported, study reveals appeared first on Smithsonian Insider.

The majority of stars in our galaxy come in pairs. In particular, the most massive stars usually have a companion. These fraternal twins tend to […]

The post Mismatched Twin Stars Spotted in the Delivery Room appeared first on Smithsonian Insider.

Studies show that on average, the weight of cremated remains for men is about 7.13 pounds (plus or minus 1.2 pounds) and for women, 4.9 […]

The post Hi-Tech Analysis Cracks Curious Case of Contaminated Cremains appeared first on Smithsonian Insider.