Transferable Aspherical Atom Model (TAAM) instead of Independent Atom Model (IAM) applied through DiSCaMB software library in the structure refinement against X-ray diffraction data largely improves the X—H bond lengths and make them comparable to the averaged neutron bond lengths.

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 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.

Most articles dealing with R2TSi3 compounds are only interested in one specific composite or in a series of composites with varying T elements while keeping R fixed (or vice versa). The present work gives an overview of the complete range of 2:1:3 silicides, similar those of Hoffmann & Pöttgen (2001) and Pan et al. (2013). In contrast to the work of Hoffmann & Pöttgen (2001), reasons for formation of the different symmetries and superstructures are discussed. Here, crystallographic properties are in[the] focus, whereas physical and magnetic properties are omitted because those are given by Pan et al. (2013). READS LIKE AN ABSTRACT, please re-write and remove references if possible. Should be two sentences max.

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.

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.

A single-chain, tailless Xenopus laevis H2A/H2B dimer construct (scH2BH2A) was engineered by directly fusing the C-terminus of H2B to the N-terminus of H2A without an artificial linker sequence. A high-resolution crystal structure of scH2BH2A shows that it adopts a nearly identical fold to that of nucleosomal H2A/H2B and may be useful for future structural studies of many H2A/H2B-interacting proteins.

The membrane protein EsaA is a conserved component of the type VIIb secretion system. Limited proteolysis of purified EsaA from Staphylococcus aureus USA300 identified a stable 48 kDa fragment, which was mapped by fingerprint mass spectrometry to an uncharacterized extracellular segment of EsaA. Analysis by circular dichroism spectroscopy showed that this fragment folds into a single stable domain made of mostly α-helices with a melting point of 34.5°C. Size-exclusion chromatography combined with multi-angle light scattering indicated the formation of a dimer of the purified extracellular domain. Octahedral crystals were grown in 0.2 M ammonium citrate tribasic pH 7.0, 16% PEG 3350 using the hanging-drop vapor-diffusion method. Diffraction data were analyzed to 4.0 Å resolution, showing that the crystals belonged to the enantiomorphic tetragonal space groups P41212 or P43212, with unit-cell parameters a = 197.5, b = 197.5, c = 368.3 Å, α = β = γ = 90°.

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.

The true identity of the protein found in the crystals reported by Bondoc et al. [(2019), Acta Cryst. F75, 646–651] is given.

For those who think that global warming is a 21st-century phenomenon, Scott Wing, a scientist at the Smithsonian’s National Museum of Natural History, has news about the past.

The post Fossils Show Prehistoric Global Warming appeared first on Smithsonian Insider.

In southeastern Greenland, two rivers of ice named Helheim and Kangerdlugssuaq flow in spurts and starts toward the coast. They are much like any other […]

The post Astrophysical Observatory scientists are monitoring the mysterious movements of glaciers appeared first on Smithsonian Insider.

The fossil teeth of a 15- to 18-million-year-old three-toed browsing horse, Anchitherium clarencei, were recently discovered by scientists from the Smithsonian Tropical Research Institute and the […]

The post Fossil teeth of 15-million-year-old browsing horse found in Panama Canal excavations. appeared first on Smithsonian Insider.

A new Smithsonian study that examines 10 million years of the evolution of tiny coral-like organisms called cupuladriid bryzoans has revealed that some species of this organism lingered on earth for more than one million years after the event that ultimately caused their extinction: the rising of the Isthmus of Panama.

The post Fossils of tiny cupuladriid colonies reveal extinction can lag more than one million years after its cause appeared first on Smithsonian Insider.

Already under siege from overfishing, disease and poor water quality, the oyster population in the Chesapeake Bay today stands at 2 percent of what it was in colonial times. Now, new data show that rising acidity in the Bay will have a negative impact on oyster shells.

The post Rising acidification of estuary waters spells trouble for Chesapeake Bay oysters appeared first on Smithsonian Insider.

New observations by the Smithsonian’s Submillimeter Array, a radio telescope atop Mauna Kea in Hawaii, are shedding light on planet formation. The array provides sharp views by combining eight antennas into the equivalent of a single, large telescope. It can resolve details as small as a dime seen from seven miles away.

The post Cosmic “baby photos” of distant solar systems lend insight as to how planets form appeared first on Smithsonian Insider.

Testing caterpillars’ taste buds is no simple task. Just like your local salad bar, plants in the wild come in different shapes, textures and flavors. Herbivores rely on each of these cues to tell them what to eat. Deciphering this code is Lind’s task. He’s examining 40 different plant species – half invasive, half native.

The post Salad science: Coaxing caterpillars to reveal the secrets of their leafy desires appeared first on Smithsonian Insider.

Scientists from the Smithsonian Migratory Bird Center at the National Zoo have taken blood samples from thousands of birds and mosquitoes in an effort to track the progress of the West Nile Virus in the eastern United States. Come along in this video as Smithsonian scientists net birds living in downtown Washington, D.C., extract small amounts of blood, and then release them back into the "wild."

The post Video: Common birds in Washington, D.C. are helping Smithsonian scientists track intensity of the West Nile Virus appeared first on Smithsonian Insider.

The spread of Africanized honey bees across Central America has had a much smaller impact on native tropical bee species than scientists previously predicted...

The post Native bees prove resilient in competition with invasive African honey bees appeared first on Smithsonian Insider.

The National Zoo has been awarded a grant from the U.S. Fish and Wildlife Service to establish a captive population of the Virginia big-eared bat at the National Zoo’s Conservation & Research Center near Front Royal, Va. Only 15,000 Virginia big-eared bats remain living in caves in West Virginia, Virginia, Kentucky and North Carolina, and these are threatened by the white-nose syndrome.

The post In face of crisis, National Zoo to start captive population of Virginia big-eared bats appeared first on Smithsonian Insider.

The Smithsonian’s National Air and Space Museum recently obtained two monumental instruments on loan from NASA’s Goddard Space Flight Center.

The post New Acquisition: Corrective instruments from the Hubble Space Telescope appeared first on Smithsonian Insider.

The newfound world, GJ1214b, is about 6.5 times as massive as the Earth. Its host star, GJ1214, is a small, red type M star about one-fifth the size of the Sun. GJ1214b orbits its star once every 38 hours at a distance of only 1.3 million miles. Astronomers estimate the planet's temperature to be about 400 degrees Fahrenheit. Although warm as an oven, it is still cooler than any other known transiting planet because it orbits a very dim star.

The post Astronomers Find Super-Earth Using Amateur, Off-the-Shelf Technology appeared first on Smithsonian Insider.

In their laboratory, scientists from the University of Cambridge, the University of Southampton and the Smithsonian Tropical Research Institute in Panama, observed as a number of adult locusts walked along a horizontal ladder. After covering the right or left eye of an insect, the scientists observed a significant increase in the error rate of rungs missed by the front leg on the side of the covered eye.

The post For first time, scientists prove locusts use vision to place their legs when walking appeared first on Smithsonian Insider.

Scientists from the Smithsonian Museum Conservation Institute, the University of Valencia in Spain and the University of Minnesota, recently made an important observation regarding charcoals […]

The post Fungi still visible in wood charcoal centuries after burning appeared first on Smithsonian Insider.

The rescue pods will be part of the project’s Amphibian Rescue Center at Summit Municipal Park, which will also include a lab with a quarantine facility.

The post Shipping industry sends help as project in Panama tackles amphibian crisis appeared first on Smithsonian Insider.

This innovative facility will be at the front line of Earth defense by searching for "killer" asteroids and comets. It will map large portions of the sky nightly, making it an efficient sleuth for not just asteroids but also supernovae and other variable objects.

The post Super sensitive telescope will detect “killer” asteroids and comets on collision course with Earth appeared first on Smithsonian Insider.

Describing a species is a serious undertaking. In the case of T. acutus, Coats and his collaborators documented its microscopic life cycle, conducted extensive DNA analysis and unearthed scientific papers dating back to 1873—when parasitic dinoflagellates were first noted by German scientist Ernst Haeckel.

The post Introducing the parasitic dinoflagellate: Tintinnophagus acutus appeared first on Smithsonian Insider.

Unless action is taken now, coral reefs and many of the animals that depend on them may cease to exist within the next 40 years, causing the first global extinction of a worldwide ecosystem during current history.

The post Scientists establish first frozen repository of Hawaiian coral appeared first on Smithsonian Insider.

To understand the effects of road salting on ants, Michael Kaspari of the Smithsonian Tropical Research Institute and the University of Oklahoma led a team that looked at how ant colonies are affected by these conditions; their research is published in a recent issue of the journal Ecological Entomology.

The post Study reveals road salt may promote health and well-being of roadside ant colonies appeared first on Smithsonian Insider.

When NASA’s Solar Probe Plus launches before the end of the decade, it will carry a suite of cutting-edge scientific instruments. Only one–the Solar Wind Electrons Alphas and Protons Investigation (SWEAP)–will directly sample the Sun’s outer atmosphere.

The post Center for Astrophysics will play major role in mission to “touch” the Sun appeared first on Smithsonian Insider.

Data from a recent study of wild takins in the high-altitude forests of the Tangjiahe National Nature Reserve in southeast China has shown that the […]

The post Great Sichuan earthquake of 2008 had little impact on of China’s wild takins appeared first on Smithsonian Insider.

A new computer simulation by Gurtina Besla of the Harvard-Smithsonian Center for Astrophysics and her colleagues now shows that the Magellanic Stream resulted from a past close encounter between two dwarf galaxies rather than effects of the Milky Way.

The post Milky Way sidelined in galactic tug of war appeared first on Smithsonian Insider.

"This galaxy cluster wins the heavyweight title. It's among the most massive clusters ever found at this distance," said Mark Brodwin, a Smithsonian astronomer at the Harvard-Smithsonian Center for Astrophysics.

The post Newly discovered massive galaxy cluster wins heavyweight title appeared first on Smithsonian Insider.

Should global warming cause sea levels to rise as predicted in coming decades, thousands of archaeological sites in coastal areas around the world will be lost to erosion. With no hope of saving all of these sites, three archaeologists—Leslie Reeder of Southern Methodist University, Jon Erlandson of the University of Oregon and Torben Rick from the Smithsonian's National Museum of Natural History—have issued a call to action for scientists to assess the sites most at risk around the world.

The post Scientists issue call to action for archaeological sites threatened by rising seas, urban development appeared first on Smithsonian Insider.

New research by astrophysicist David Kipping has revealed that in some special cases, a star can be weighed directly. Such a star must have a planet orbiting it with a moon orbiting the planet.

The post Harvard-Smithsonian astrophysicist discovers new method to weigh some distant stars appeared first on Smithsonian Insider.

Known as one of the greatest racehorses of his day and sire to more winning horses than any other American thoroughbred before or since, this Smithsonian loan returned the legendary Lexington's remains to the town of his birthplace some 160 years after he was born.

The post One hundred sixty years after his birth a racehorse’s bones return to Lexington appeared first on Smithsonian Insider.

This 'hot Jupiter', now named Qatar-1b, adds to the growing list of alien planets orbiting distant stars, or exoplanets. Its discovery demonstrates the power of science to cross political boundaries and increase ties between nations.

The post International team discovers alien planet that’s Jupiter-sized appeared first on Smithsonian Insider.

Twenty years ago scientists at the Marine Invasions Lab of the Smithsonian Environmental Research Center in Edgewater, Md., began studying the interactions between native grass […]

The post Invasive oriental shrimp found in Chesapeake Bay by Smithsonian scientists appeared first on Smithsonian Insider.

"Physics for the 21st Century," a free, on-line course developed at the Harvard-Smithsonian Center for Astrophysics about current research in physics is now available.

The post Free, online course in physics offered by the Harvard-Smithsonian Center for Astrophysics appeared first on Smithsonian Insider.

The new agreement, effective immediately through Dec. 5, 2015, stipulates that the Smithsonian's National Zoological Park will conduct research in the areas of giant panda breeding and cub behavior.

The post Smithsonian signs new giant panda agreement with China appeared first on Smithsonian Insider.

A recent experiment by scientists at the Smithsonian Tropical Research Institute in Panama has revealed just how rising atmospheric carbon dioxide will deliver a one-two […]

The post Rising ocean temperatures and acidity may deliver deadly one-two punch to the world’s corals appeared first on Smithsonian Insider.

In a new paper, Harvard-Smithsonian Center for Astrophysics astronomer Hagai Perets studies the role of binary planetesimals--clumps that orbit each other and jointly mature via three basic processes.

The post New study examines how planetesimals influence the development of a planetary system appeared first on Smithsonian Insider.

The male’s fluke design helps it overcome the drag caused by their long tusks, the scientists determined. The female’s fluke design gives them increased speed for diving while foraging.

The post Narwhal fluke design helps compensate for drag caused by tusk appeared first on Smithsonian Insider.

A new species of Brazilian leaf beetle named Cachiporra extremaglobosa, (which translated means the “extremely globular billy club leaf beetle,”) was recently discovered by scientists at the Smithsonian’s National Museum of Natural History.

The post “Billy club” leaf beetle has been hiding in Smithsonian collections since 1959 appeared first on Smithsonian Insider.

Last week, the Kepler team and CfA astronomers announced the discovery of a system of six transiting planets around one Sun-like star. The previous record holder for the number of transiting planets was three.

The post Six orbiting planets sets record for Sun-like stars say Kepler, Smithsonian astronmers appeared first on Smithsonian Insider.

Astronomers are piecing together the reasons for these huge energy outputs, while sorting out why our own galaxy is so modest. The two primary suspects are bursts of star formation that produce many hot young stars, and processes associated with accretion of material onto a supermassive black hole at a galaxy's nucleus.

The post Luminosity of extreme galaxy most likely driven by star formation appeared first on Smithsonian Insider.

Funded by BP through the Florida Institute of Oceanography, the scientists will make the 10-day trip aboard the institute’s 115-foot research vessel. The divers, scientists and photographers will document hard bottoms of Florida, from the Keys to the Panhandle, to gain a better understanding of these sponge- and coral-dominated communities

The post Gulf of Mexico survey will benchmark diversity of ocean floor appeared first on Smithsonian Insider.

In recent research on Santa Rosa Island off the coast of Southern California, isotope readings of carbon and nitrogen found in the bones of Chumash Indians and domestic dogs excavated from archaeological sites show that both humans and dogs have nearly identical signatures of stable isotopes.

The post Ancient bond between humans and dogs revealed in isotopic signatures of their bones appeared first on Smithsonian Insider.

As researchers investigate the impact of the Burmese python in the Everglades, scientists from the Smithsonian Institution, South Florida Natural Resources Center and the University of Florida examined the snake’s predation of the area’s birds. They found that birds, including endangered species, accounted for 25 percent of the python’s diet in the Everglades.

The post Invasive Burmese pythons are taking a toll on Florida’s native birds appeared first on Smithsonian Insider.