Owing to their combined open-framework structures and semiconducting properties, two-dimensional thio­stannates show great potential for catalytic and sensing applications. One such class of crystalline materials consists of porous polymeric [Sn3S72−]n sheets with molecular cations embedded in-between. The compounds are denoted R-SnS-1, where R is the cation. Dependent on the cation, some R-SnS-1 thio­stannates transition into amorphous phases upon dispersion in water. Knowledge about the fundamental chemical properties of the thio­stannates, including their water stability and the nature of the amorphous products, has not yet been established. This paper presents a time-resolved study of the transition from the crystalline to the amorphous phase of two violet-light absorbing thio­stannates, i.e. AEPz-SnS-1 [AEPz = 1-(2-amino­ethyl)­piperazine] and trenH-SnS-1 [tren = tris­(2-amino­ethyl)­amine]. X-ray total scattering data and pair distribution function analysis reveal no change in the local intralayer coordination during the amorphization. However, a rapid decrease in the crystalline domain sizes upon suspension in water is demonstrated. Although scanning electron microscopy shows no significant decrease of the micrometre-sized particles, transmission electron microscopy reveals the formation of small particles (∼200–400 nm) in addition to the larger particles. The amorphization is associated with disorder of the thio­stannate nanosheet stacking. For example, an average decrease in the interlayer distance (from 19.0 to 15.6 Å) is connected to the substantial loss of the organic components as shown by elemental analysis and X-ray photoelectron spectroscopy. Despite the structural changes, the light absorption properties of the amorphisized R-SnS-1 compounds remain intact, which is encouraging for future water-based applications of such materials.

Human carbonic anhydrase IX (CA IX) expression is upregulated in hypoxic solid tumours, promoting cell survival and metastasis. This observation has made CA IX a target for the development of CA isoform-selective inhibitors. To enable structural studies of CA IX–inhibitor complexes using X-ray and neutron crystallography, a CA IX surface variant (CA IXSV; the catalytic domain with six surface amino-acid substitutions) has been developed that can be routinely crystallized. Here, the preparation of protiated (H/H), H/D-exchanged (H/D) and deuterated (D/D) CA IXSV for crystallographic studies and their structural comparison are described. Four CA IXSV X-ray crystal structures are compared: two H/H crystal forms, an H/D crystal form and a D/D crystal form. The overall active-site organization in each version is essentially the same, with only minor positional changes in active-site solvent, which may be owing to deuteration and/or resolution differences. Analysis of the crystal unit-cell packing reveals different crystallographic and noncrystallographic dimers of CA IXSV compared with previous reports. To our knowledge, this is the first report comparing three different deuterium-labelled crystal structures of the same protein, marking an important step in validating the active-site structure of CA IXSV for neutron protein crystallography.

Reducing the sample-exchange time is a crucial issue in maximizing the throughput of macromolecular crystallography (MX) beamlines because the diffraction data collection itself is completed within a minute in the era of pixel-array detectors. To this end, an upgraded sample changer, SPACE-II, has been developed on the basis of the previous model, SPACE (SPring-8 Precise Automatic Cryo-sample Exchanger), at the BL41XU beamline at SPring-8. SPACE-II achieves one sample-exchange step within 16 s, of which its action accounts for only 11 s, because of three features: (i) the implementation of twin arms that enable samples to be exchanged in one cycle of mount-arm action, (ii) the implementation of long-stroke mount arms that allow samples to be exchanged without withdrawal of the detector and (iii) the use of a fast-moving translation and rotation stage for the mount arms. By pre-holding the next sample prior to the sample-exchange sequence, the time was further decreased to 11 s in the case of automatic data collection, of which the action of SPACE-II accounted for 8 s. Moreover, the sample capacity was expanded from four to eight Uni-Pucks. The performance of SPACE-II has been demonstrated in over two years of operation at BL41XU; the average number of samples mounted on the diffractometer in one day was increased from 132 to 185, with an error rate of 0.089%, which counted incidents in which users could not continue with an experiment without recovery work by entering the experimental hutch. On the basis of these results, SPACE-II has been installed at three other MX beamlines at SPring-8 as of July 2019. The fast and highly reliable SPACE-II is now one of the most important pieces of infrastructure for the MX beamlines at SPring-8, providing users with the opportunity to fully make use of limited beamtime with brilliant X-rays.

In this paper, the design and functionalities of the high-throughput TELL sample exchange system for macromolecular crystallography is presented. TELL was developed at the Paul Scherrer Institute with a focus on speed, storage capacity and reliability to serve the three macromolecular crystallography beamlines of the Swiss Light Source, as well as the SwissMX instrument at SwissFEL.

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 Smithsonian Center for Education and Museum Studies is hosting “Climate Change,” a three-day, free, education online conference Tuesday, Sept. 29 through Thursday, Oct. 1. This […]

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It is one of the largest and most productive estuaries in the world, yet dramatic changes are in store for the Chesapeake Bay in coming […]

The post Climate change may drastically alter Chesapeake Bay, scientists say appeared first on Smithsonian Insider.

Based on decades of cutting-edge research, the 15,000-square-foot Hall of Human Origins offers visitors an immersive, interactive journey through 6 million years of human evolution spelling out how defining characteristics of the human species have evolved during millions of years in response to a changing world.

The post New Hall of Human Origins points to environmental change as major force in evolution of hominins appeared first on Smithsonian Insider.

BROOKINGS, S.D. — Julie DeJong can’t set foot on the ground of an Oregon marsh to gather duck eggs on a spring day in 1875. […]

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The predictability and scale of seasonal changes in a habitat help determine the distance migratory species move and whether the animals always travel together to the same place or independently to different locations.

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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 […]

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Paleontologists studying an extreme short-term global warming event have discovered direct evidence about how mammals respond to rising temperatures. In a study that appeared recently […]

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

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A specimen recently pulled from deep in the southwest Atlantic may represent a new species of squid, say scientist who have studied the animal’s unusual morphology. But then again, it may not…

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Justin Touchon, post-doctoral fellow at the Smithsonian Tropical Research Institute, discovered that climate change in Panama may be altering frogs’ course of evolution.

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Found in well preserved shale deposits the fossils are so detailed that scientists were able to determine they represent two previously unknown species.

The post Discovery of new prehistoric mosquitoes reveal these blood-suckers have changed little in 46 million years 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 […]

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The Republic of Panama’s proposal to implement four Traffic Separation Schemes for commercial vessels entering and exiting the Panama Canal and ports was approved unanimously […]

The post Commercial shipping lanes changed in Panama to save humpback whales appeared first on Smithsonian Insider.

Amid efforts to restore native oyster populations on the West Coast, how are oysters expected to fare under climate change in the decades and centuries […]

The post Climate Change May Benefit Native Oysters, but There’s a Catch appeared first on Smithsonian Insider.

Tidal Freshwater Wetlands focuses on wetlands found in North America and Europe near the mouths of rivers that flow into estuaries like the Chesapeake Bay.

The post New book reveals tidal freshwater wetlands are on frontlines of global change appeared first on Smithsonian Insider.

Even tiny crustaceans scuttling across the deepest, darkest depths of the ocean floor will feel the effects of climate change, according to a new study […]

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Many traits unique to humans were long thought to have originated in the genus Homo between 2.4 and 1.8 million years ago in Africa. A […]

The post Human Evolution Rewritten: We owe our existence to our ancestor’s flexible response to climate change appeared first on Smithsonian Insider.

A full 94 percent of the dead zones in the world’s oceans lie in regions expected to warm at least 2 degrees Celsius by the […]

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The last time Earth experienced both ice sheets and carbon dioxide levels within the range predicted for this century was a period of major sea […]

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The HSBC Climate Partnership (HCP) is a five-year partnership (2007-2011) between HSBC, The Smithsonian, The Climate Group, Earthwatch Institute and WWF to inspire action on climate change.
Working with these partners and engaging its employees around the world, HSBC hopes to tackle climate change impacts for people, forests, water, and cities. The HCP research of the Smithsonian's Center for Tropical Forest Science (CTFS) focuses on:
• Understanding the role of forests in the global carbon cycle
• Comparing temperate and tropical forests by establishing new plots in the temperate zone
• Quantifying the environmental services provided by tropical forests

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When Smithsonian Tropical Research Institute paleobotanist Carlos Jaramillo learned that Panama was expanding its canal in 2006 and blasting 100 million tons of rock to […]

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  Frances Glessner Lee created dollhouses with dead dolls. Her creations are now on exhibit at the Renwick Gallery of the Smithsonian American Art Museum.

The post The dollhouses of death that changed forensic science appeared first on Smithsonian Insider.

Smithsonian plant physiologist Bert Drake has studied one wetland's response to climate change for more than two decades. He gives a tour of the field experiment and explains some of the findings.

The post On the Chesapeake Bay, Smithsonian plant physiologist Bert Drake has been studying one wetland’s response to climate change for more than two decades. appeared first on Smithsonian Insider.

Phragmites australis, the common reed, has been a component of North American marshes for thousands of years. However, a novel genetic lineage, Phragmites australis australis, […]

The post Climate change conundrum: Invasive reed makes much more methane appeared first on Smithsonian Insider.

This year’s El Niño event is one of the strongest on record and is still ramping up. Large parts of the tropics are turning into […]

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The global conservation movement has reached a turning point. We have documented the fast pace of habitat loss, the growing number of endangered and extinct […]

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The Earth’s changing climate could cause the extinction of up to a third of its parasite species by 2070, according to a global analysis reported […]

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In certain scenarios, a Subsystem Reference block changes its position. It can happen during: 

1. Loading of top model which contains the Subsystem Reference block 
2. Synchronization of Subsystem Reference block's contents
3. Converting a subsystem to Subsystem Reference block 

The Council of the National Academy of Sciences (NAS) is concerned about the confusion caused by a petition being circulated via a letter from a former president of this Academy.

Reducing one of the nations leading causes of death and injury – medical errors – will require rigorous changes throughout the health care system, including mandatory reporting requirements.

To enhance the vitality and overall operation of the nations patent system, federal officials should take decisive steps to increase the systems flexibility, openness, and reliability, says a new report from the National Academies National Research Council.

Although most people who receive and manage Social Security benefits on behalf of other individuals perform their duties well.

While every mode of transportation in the U.S. will be affected as the climate changes, potentially the greatest impact on transportation systems will be flooding of roads, railways, transit systems, and airport runways in coastal areas because of rising sea levels and surges brought on by more intense storms, says a new report from the National Research Council.

The aging of the U.S. population will have broad economic consequences for the country, particularly for federal programs that support the elderly, and its long-term effects on all generations will be mediated by how -- and how quickly -- the nation responds, says a new congressionally mandated report from the National Research Council.

The U.S. National Academy of Sciences and the Royal Society, the national science academy of the U.K., released a joint publication today in Washington, D.C., that explains the clear evidence that humans are causing the climate to change, and that addresses a variety of other key questions commonly asked about climate change science.

It is now possible to estimate the influence of climate change on some types of extreme events, such as heat waves, drought, and heavy precipitation, says a new report from the National Academies of Sciences, Engineering, and Medicine.

Today President Obama signed a Presidential Memorandum to address climate change and national security. The National Academies of Sciences, Engineering, and Medicine look forward to taking the lead in engaging the academic community in efforts to guide this initiative, and are well-positioned to tap the broad, multidisciplinary expertise of researchers across the nation.