The Python-based program py_convrot is a universal converter of rigid-body rotation parameters. The program interactively illustrates the action of various rotation parameters and can be used both for teaching goals and for practical applications.

An X-ray cross-correlation study of the impact of ligand composition and salt content on the self-assembly of soft-shell nanoparticles is presented, indicating symmetry-selective formation of order.

Ba excess in LaBaGaO4 triggers ionic conductivity together with structural disorder. A direct correlation is found between the density functional theory model energy and the pair distribution function fit residual.

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

This article presents the capability of the QMAX furnace, devoted to reciprocal space mapping through X-ray scattering at high temperature up to 2000 K.

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

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.

The proton-conducting material (NH4)4H2(SeO4)3 is examined to check whether its conductivity spectra are sensitive to subtle changes in the crystal structure and proton dynamics caused by external pressure. The AC conductivity was measured using impedance spectroscopy, in the frequency range from 100 Hz to 1 MHz, at temperatures 260 K < T < 400 K and pressures 0.1 MPa < p < 500 MPa. On the basis of the impedance spectra, carefully analyzed at different thermodynamic conditions, the p–T phase diagram of the crystal is constructed. It is found to be linear in the pressure range of the experiment, with the pressure coefficient value dTs/dp = −0.023 K MPa−1. The hydrostatic pressure effect on proton conductivity is also presented and discussed. Measurements of the electrical conductivity versus time were performed at a selected temperature T = 352.3 K and at pressures 0.1 MPa < p < 360 MPa. At fixed thermodynamic conditions (p = 302 MPa, T = 352.3 K), the sluggish solid–solid transformation from low conducting to superionic phase was induced. It is established that the kinetics of this transformation can be described by the Avrami model with an effective Avrami index value of about 4, which corresponds to the classical value associated with the homogeneous nucleation and three-dimensional growth of a new phase.

The proton-conducting crystal (NH4)4H2(SeO4)3 is examined to check whether its conductivity spectra and the phase transition to the superprotonic phase are sensitive to subtle changes in the crystal structure and proton dynamics caused by various thermodynamic conditions. It is established that the kinetics of this transformation can be described using the Avrami model with an effective Avrami index value associated with homogeneous nucleation and three-dimensional growth of a new phase.

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.

Crystal structure and microscopic optical properties of anthracene derivative compounds have been investigated by single-crystal synchrotron X-ray diffraction, laser confocal microscopy and fluorescence lifetime imaging microscopy.

Cytisine, a natural product with high affinity for clinically relevant nicotinic acetylcholine receptors (nAChRs), is used as a smoking-cessation agent. The compound displays an excellent clinical profile and hence there is an interest in derivatives that may be further improved or find use in the treatment of other conditions. Here, the binding of a cytisine derivative modified by the addition of a 3-(hydroxypropyl) moiety (ligand 4) to Aplysia californica acetylcholine-binding protein (AcAChBP), a surrogate for nAChR orthosteric binding sites, was investigated. Isothermal titration calorimetry revealed that the favorable binding of cytisine and its derivative to AcAChBP is driven by the enthalpic contribution, which dominates an unfavorable entropic component. Although ligand 4 had a less unfavorable entropic contribution compared with cytisine, the affinity for AcAChBP was significantly diminished owing to the magnitude of the reduction in the enthalpic component. The high-resolution crystal structure of the AcAChBP–4 complex indicated close similarities in the protein–ligand interactions involving the parts of 4 common to cytisine. The point of difference, the 3-(hydroxypropyl) substituent, appears to influence the conformation of the Met133 side chain and helps to form an ordered solvent structure at the edge of the orthosteric binding site.

Each year thousands of vacationers enjoy the scenery along Virginia’s Skyline Drive, little knowing that for a few brief moments they are passing through the territory of an endangered […]

The post Study aims to give endangered Shenandoah salamander better odds at survival appeared first on Smithsonian Insider.

Today the Smithsonian Institution announced Eva J. Pell, Senior Vice President for Research and Dean of the Graduate School at Pennsylvania State University, will be the new Under Secretary for Science at the Institution.

The post Smithsonian Names Eva Pell as Under Secretary for Science appeared first on Smithsonian Insider.

Native to Africa and Madagascar, females of the species have a body length of 1.5 inches and a leg span of 4 to 5 inches. Males are tiny in comparison.

The post Females are giants in newly discovered species of golden orb weaver spider appeared first on Smithsonian Insider.

“Spinning under the influence” is one way to describe recent activities in the Costa Rican laboratory of Smithsonian scientist William Eberhard. An entomologist at the Smithsonian’s Tropical Research Institute, Eberhard recently carried out a series of experiments in which he observed the web-building behavior of dozens of spiders under the influence of drugs—specifically, a chemical injected into their bodies by parasitic wasps.

The post Drugged spiders’ web spinning may hold keys to understanding animal behavior appeared first on Smithsonian Insider.

When it comes to brains, is bigger better? Can the tiny brain of a newly hatched spiderling handle problems as adeptly as the brain of a larger adult spider?

The post Tiny, new brains prove just as adept as large, mature brains among tropical orb-web spiders appeared first on Smithsonian Insider.

The Smithsonian’s National Zoo recently acquired Japanese giant salamanders given to the Zoo by the City of Hiroshima Asa Zoological Park. This donation will be the foundation of a new long-term breeding program in the United States and may play an important role in saving amphibians around the globe.

The post Japanese giant salamanders given to the National Zoo by Asa Zoological Park in Hiroshima appeared first on Smithsonian Insider.

Darwin's bark spider cast giant webs across streams, rivers and lakes, suspending the web’s orb above water and attaching it to plants on each riverbank. Bridgelines of these water-spanning webs have been measured as long as 25 meters.

The post Newly discovered Madagascar spider spins largest, toughest webs on record appeared first on Smithsonian Insider.

A roundup of recent articles featuring spiders, bats and rats....

The post A Halloween roundup featuring recent articles on spiders, bats and rats appeared first on Smithsonian Insider.

The Scarlet Knight, as the glider is called, made nautical history as the first submersible glider to successfully cross the Atlantic Ocean.

The post Rutgers glider added to the collections of the National Museum of Natural History appeared first on Smithsonian Insider.

To help regulators and engineers develop and test such treatment systems, and ultimately enforce these standards, a team of researchers developed a statistical model to see how to count small, scarce organisms in large volumes of water accurately.

The post Smithsonian researchers help block ship-borne bioinvaders with new screening strategy appeared first on Smithsonian Insider.

In a recent study of the mating behavior of these Asian spiders, researchers found that 87.5 percent of males had both palps amputated during copulation.

The post Don’t pick a fight with a eunuch spider. It has nothing to lose 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.

Now, a new study of hellbenders by scientists at the Smithsonian Conservation Biology Institute will place these amphibians at the center of the conservation of Appalachian salamanders.

The post Will global warming be hell on the hellbender? Smithsonian study aims to find out. appeared first on Smithsonian Insider.

A new study by a team of scientists from the Smithsonian’s National Museum of Natural History, the National University of Singapore and the Slovenian Academy of Sciences and Arts have unlocked the secret to mate binding in orb web spiders, and revealed just how it calms the cannibalistic female spider.

The post Suitor’s gentle massage soothes aggressive, cannibalistic female spiders, researchers find appeared first on Smithsonian Insider.

In honor of Halloween, Michael Miller, keeper in the National Zoological Park's Invertebrate Exhibit, shares a few of his favorite "strange-but-true" spider facts.

The post 8 strange but true spider facts 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.

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New research on tiny spiders has revealed that their brains are so large that they fill their body cavities and overflow into their legs, say a team of scientists at the Smithsonian Tropical Research Institute in Panama.

The post Brains of tiny spiders fill their body cavities and legs, Smithsonian researchers discover appeared first on Smithsonian Insider.

In 2011, scholars from three institutions—National Museum of American History Curators Carlene Stephens and Shari Stout, Library of Congress Digital Conversion Specialist Peter Alyea and Lawrence Berkeley National Laboratory Scientists Carl Haber and Earl Cornell—came together in a newly designed preservation laboratory at the Library of Congress to recover sound from those recordings made more than 100 years ago.

The post Digital technology allows Alexander Graham Bell’s 1880s disc recordings to be played again appeared first on Smithsonian Insider.

In fact, researchers have learned, the detached male pedipalps transfer more sperm faster after copulation is ended by the female rather than the male.

The post Male spider’s sexual organs work fastest only when a female breaks them off appeared first on Smithsonian Insider.

Researchers at the Smithsonian Tropical Research Institute and University of Costa Rica studying why spiders do not stick to their own sticky webs have discovered that a spider's legs are protected by a covering of branching hairs and by a non-stick chemical coating. Their results are published online in the journal, Naturwissenschaften.

The post Fancy footwork and non-stick leg coating helps spiders not stick to their own webs appeared first on Smithsonian Insider.

The only explanation for such symmetry across these vast distances, explains Smithsonian anthropologist Dennis Stanford, is that the method of creating the points was handed down from person to person.

The post 3-D imaging adds remarkable new understanding of North America’s mysterious Clovis people appeared first on Smithsonian Insider.

Recent geologic mapping of the Medusae Fossae Formation on Mars—an intensely eroded deposit near the northern edge of the cratered highlands—has revealed a wider distribution of its western component than was previously recognized.

The post New mapping of Mars shows Medusae Fossae Formation older than once thought appeared first on Smithsonian Insider.

The scientists made the spiders exercise by irritating them with a small paint brush and causing them to move around until they became exhausted. Spiders from the group with palps removed were able to travel 300 percent further than spiders with their palps intact.

The post Weight of genitals reduces physical endurance in male orb web spiders, researchers find 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.

One such parasite lurks in Chesapeake Bay: an invasive barnacle that hijacks a mud crab’s reproductive system and impregnates it with parasite larvae—even if the crab is male.

The post Undersea parasite turns male mud crabs female appeared first on Smithsonian Insider.

The new Sant Director of the National Museum of Natural History, Kirk Johnson, had only been on the job for 26 days when he got […]

The post Female “spidernaut” settles into new home at Smithsonian’s Insect Zoo appeared first on Smithsonian Insider.

Using echolocation alone the bats found, identified and captured insects perched motionless and silent on the leaves of plants.

The post Common tropical bat uses echolocation with precision previously considered impossible, new experiments reveal appeared first on Smithsonian Insider.

The inventions of Alexander Graham Bell—most famously the telephone but also methods of recording sound—have allowed people to hear each other’s voices for more than […]

The post “Hear My Voice”: Smithsonian identifies 130-year-old recording as Alexander Graham Bell’s voice appeared first on Smithsonian Insider.

Hellbenders, aquatic salamanders from the eastern United States, are surprisingly good at dealing with unpredictable weather. In a recent study published in the Journal of […]

The post Zoo scientists find sudden stream temperature changes boost hellbender immune systems 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.

It is related to one of the world’s most destructive invasive species, and possibly the slimiest. Thirty-five pounds of live giant West African snails (Archachatina […]

The post Slimy invaders, giant snails: Q&A with mollusk expert Ellen Strong appeared first on Smithsonian Insider.

1. Some male spiders just want to be eaten Black widows are known for cannibalizing their mates, but this doesn’t actually happen all the time. […]

The post Eight strange but true spider facts appeared first on Smithsonian Insider.

Bright orange with a distinctive call the Panamanian poison dart frog Andinobates geminisae lives in only a small area of the Caribbean Coast of Panama. […]

The post In modern amphibian “ark,” new species added with due diligence appeared first on Smithsonian Insider.

Within the 1608 church where Pocahontas and John Rolfe married, the skeletal remains of four early settlers were uncovered during a 2013 archaeological dig at […]

The post Jamestown skeletons identified as colony leaders appeared first on Smithsonian Insider.

Neanderthals (Homo neanderthalensis) were widespread across Europe and Western Asia for a long time, starting about 400,000 years ago. But things began to change when […]

The post Why did Neanderthals go extinct? appeared first on Smithsonian Insider.

Salamanders are typically elusive animals and adept at hiding, but National Zoo visitors will have a chance to see a variety of different amphibian species […]

The post National Zoo Opens New Home for Appalachian Salamanders appeared first on Smithsonian Insider.

If you were an average person in the 18th and early 19th centuries, chances are your wardrobe was 50 shades of beige, with maybe a […]

The post A Purple Accident and Its Vibrant Impact on the Modern World appeared first on Smithsonian Insider.

New high-speed videos of 14 species of tiny Mecysmaucheniid “trap-jaw” spiders have revealed that some species can snap their mouth parts shut at incredibly fast […]

The post Discovery: trap-jaw spiders snap prey with super-spidey speed and power appeared first on Smithsonian Insider.