The X-chromosome-linked inhibitor of apoptosis protein (XIAP) is a multidomain protein whose main function is to block apoptosis by caspase inhibition. XIAP is also involved in other signalling pathways, including NF-κB activation and copper homeostasis. XIAP is overexpressed in tumours, potentiating cell survival and resistance to chemotherapeutics, and has therefore become an important target for the treatment of malignancy. Despite the fact that the structure of each single domain is known, the conformation of the full-length protein has never been determined. Here, the first structural model of the full-length XIAP dimer, determined by an integrated approach using nuclear magnetic resonance, small-angle X-ray scattering and electron paramagnetic resonance data, is presented. It is shown that XIAP adopts a compact and relatively rigid conformation, implying that the spatial arrangement of its domains must be taken into account when studying the interactions with its physiological partners and in developing effective inhibitors.

Among different types of polymorphism, disappearing polymorphism deals with the metastable kinetic form which can not be reproduced after its first isolation. In the world of coordination polymers (CPs) and metal–organic frameworks (MOFs), despite the fact that many types of supramolecular isomerism exist, we are unaware of disappearing supramolecular isomerism akin to disappearing polymorphism. This work reports a MOF with dia topology that could not be reproduced, but subsequent synthesis yielded another supramolecular isomer, a double-pillared-layer MOF. When perylene was added in the same reaction, the disappeared dia MOF reappeared with perylene as a guest in the channels. Interestingly, the photoluminescence of the dia MOF with a perylene guest is dominated by the emission of the guest molecule. The influence of guest molecules on the stabilization of the supramolecular isomers of a MOF opens up a strategy to access MOFs with different structures.

Different approaches of 2D lens arrays as Shack–Hartmann sensors for hard X-rays are compared. For the first time, a combination of Shack–Hartmann sensors for hard X-rays (SHSX) with a super-resolution imaging approach to perform multi-contrast imaging is demonstrated. A diamond lens is employed as a well known test object. The interleaving approach has great potential to overcome the 2D lens array limitation given by the two-photon polymerization lithography. Finally, the radiation damage induced by continuous exposure of an SHSX prototype with a white beam was studied showing a good performance of several hours. The shape modification and influence in the final image quality are presented.

The Advanced Photon Source 1-ID beamline, operating in the 40–140 keV X-ray energy range, has successfully employed continuously tunable saw-tooth refractive lenses to routinely deliver beams focused in both one and two dimensions to experiments for over 15 years. The practical experience of implementing such lenses, made of silicon and aluminium, is presented, including their properties, control, alignment, and diagnostic methods, achieving ∼1 µm focusing (vertically). Ongoing development and prospects towards submicrometre focusing at these high energies are also mentioned.

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 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 gluconate 5-dehydrogenase from Lentibacter algarum is reported. It has high structural similarity to other gluconate 5-dehydrogenase proteins, demonstrating that this enzyme is highly conserved.

The Smithsonian Tropical Research Institute in Panama was recently given a collection of more than 25,000 different pollen grains and spores, each mounted on a microscope slide and labeled according to the plant that produced it. “The collection is worldwide in coverage with an emphasis on plants of the Americas,” explains collection donor Alan Graham, professor emeritus at Kent State University and curator at the Missouri Botanical Garden.

The post Research collection of pollen grains given to Smithsonian Tropical Research Institute 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.

Staff had been on a pregnancy watch focused on the 3 1/2-year-old clouded leopard Jao Chu (JOW-chew) for four days. Jao Chu gave birth to the first cub at 6:04 p.m. and the second cub at 6:20 p.m.

The post Clouded leopard cubs born at National Zoo’s Front Royal campus on Valentine’s Day appeared first on Smithsonian Insider.

Discoveries of three new from species in Panama lead to hope that project researchers can save these animals from a deadly fungus killing frogs worldwide and the fear that many species will go extinct before scientists even know they exist.

The post New frog species pose challenge for conservation project in Panama appeared first on Smithsonian Insider.

Using modern genetic analysis, combined with traditional morphology, scientists from the Smithsonian’s National Museum of Natural History and the Ocean Science Foundation have discovered seven […]

The post Smithsonian scientists discover seven new species of blenny fish appeared first on Smithsonian Insider.

This image shows the active star-forming galaxy M82 in three wavelengths: UV (blue), near-infrared (green) and far-infrared (red). New research indicates that even in the […]

The post Active star-forming galaxy M82 in three wavelengths 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.

Who: Wheelerodemus muhlenbergiae What: A newly discovered species of plant eating bug belonging to the family Blissidae, members of which are found worldwide. W. muhlenbergiae […]

The post Meet a new true bug: “Wheelerodemus muhlenbergiae” appeared first on Smithsonian Insider.

The Smithsonian’s National Portrait Gallery celebrates the accomplishments of astronaut and Senator John Glenn (1921-2016) with a watercolor and graphite portrait by Henry C. Caselli […]

The post John Glenn Portrait on View at National Portrait Gallery appeared first on Smithsonian Insider.

This winter has brought many intense and powerful storms, with cold fronts sweeping across much of the United States. On a much grander scale, astronomers […]

The post Scientists surprised by relentless cosmic cold front appeared first on Smithsonian Insider.

The bond-valence method has been used for valence calculations of FeMo/V cofactors in FeMo/V proteins using 51 crystallographic data sets of FeMo/V proteins from the Protein Data Bank. The calculations show molybdenum(III) to be present in MoFe7S9C(Cys)(HHis)[R-(H)homocit] (where H4homocit is homocitric acid, HCys is cysteine and HHis is histidine) in FeMo cofactors, while vanadium(III) with a more reduced iron complement is obtained for FeV cofactors. Using an error analysis of the calculated valences, it was found that in FeMo cofactors Fe1, Fe6 and Fe7 can be unambiguously assigned as iron(III), while Fe2, Fe3, Fe4 and Fe5 show different degrees of mixed valences for the individual Fe atoms. For the FeV cofactors in PDB entry 5n6y, Fe4, Fe5 and Fe6 correspond to iron(II), iron(II) and iron(III), respectively, while Fe1, Fe2, Fe3 and Fe7 exhibit strongly mixed valences. Special situations such as CO-bound and selenium-substituted FeMo cofactors and O(N)H-bridged FeV cofactors are also discussed and suggest rearrangement of the electron configuration on the substitution of the bridging S atoms.

Bipasha Dey and Richa Rikhy

Cell shape morphogenesis from spherical to polygonal occurs in epithelial cell formation in metazoan embryogenesis. In syncytial Drosophila embryos, the plasma membrane incompletely surrounds each nucleus and is organized as a polygonal epithelial-like array. Each cortical syncytial division cycle shows circular to polygonal plasma membrane transition along with furrow extension between adjacent nuclei from interphase to metaphase. In this study, we assess the relative contribution of DE-cadherin and Myosin II at the furrow for polygonal shape transition. We show that polygonality initiates during each cortical syncytial division cycle when the furrow extends from 4.75 to 5.75 µm. Polygon plasma membrane organization correlates with increased junctional tension, increased DE-cadherin and decreased Myosin II mobility. DE-cadherin regulates furrow length and polygonality. Decreased Myosin II activity allows for polygonality to occur at a lower length than controls. Increased Myosin II activity leads to loss of lateral furrow formation and complete disruption of polygonal shape transition. Our studies show that DE-cadherin-Myosin II balance regulates an optimal lateral membrane length during each syncytial cycle for polygonal shape transition.

Sanjeev Chavan Nayak and Vegesna Radha

C3G (RapGEF1) plays a role in cell differentiation and is essential for early embryonic development in mice. In this study, we identify C3G as a centrosomal protein colocalizing with cenexin at the mother centriole in interphase cells. C3G interacts through its catalytic domain with cenexin, and they show interdependence for localization to the centrosome. C3G depletion caused a decrease in cellular cenexin levels. Centrosomal localization is lost as myocytes differentiate to form myotubes. Stable clone of cells depleted of C3G by CRISPR/Cas9 showed the presence of supernumerary centrioles. Overexpression of C3G, or a catalytically active deletion construct inhibited centrosome duplication. Cilia length is longer in C3G knockout cells, and the phenotype could be reverted upon reintroduction of C3G or its catalytic domain. Association of C3G with the basal body is dynamic, decreasing upon serum starvation, and increasing upon reentry into the cell cycle. C3G inhibits cilia formation and length dependent on its catalytic activity. We conclude that C3G inhibits centrosome duplication and maintains ciliary homeostasis, properties that may be important for its role in embryonic development.

Volcanoes are a source of fascination for many, attracting a steady stream of visitors worldwide. While the danger of sudden eruptions may add to the […]

The post When will a volcano explode, ooze or lie silent? appeared first on Smithsonian Insider.

What was happening (geologically speaking) on Earth way back when it was a mere babe and being showered with meteorites? Until a time machine is […]

The post Beautiful meteorites hold clues to solar system’s violent start appeared first on Smithsonian Insider.

Single-wavelength X-ray anomalous diffraction (SAD) is a frequently employed technique to solve the phase problem in X-ray crystallography. The precision and accuracy of recovered anomalous differences are crucial for determining the correct phases. Continuous rotation (CR) and inverse-beam geometry (IBG) anomalous data collection methods have been performed on tetragonal lysozyme and monoclinic survivin crystals and analysis carried out of how correlated the pairs of Friedel's reflections are after scaling. A multivariate Bayesian model for estimating anomalous differences was tested, which takes into account the correlation between pairs of intensity observations and incorporates the a priori knowledge about the positivity of intensity. The CR and IBG data collection methods resulted in positive correlation between I(+) and I(−) observations, indicating that the anomalous difference dominates between these observations, rather than different levels of radiation damage. An alternative pairing method based on near simultaneously observed Bijvoet's pairs displayed lower correlation and it was unsuccessful for recovering useful anomalous differences when using the multivariate Bayesian model. In contrast, multivariate Bayesian treatment of Friedel's pairs improved the initial phasing of the two tested crystal systems and the two data collection methods.

The transformations from the primitive cells of the centered Bravais lattices to the corresponding centered cells have conventionally been listed as three-by-three matrices that transform three-space lattice vectors. Using those three-by-three matrices when working in the six-dimensional space of lattices represented as Selling scalars as used in Delone (Delaunay) reduction, one could transform to the three-space representation, apply the three-by-three matrices and then back-transform to the six-space representation, but it is much simpler to have the equivalent six-by-six matrices and apply them directly. The general form of the transformation from the three-space matrix to the corresponding matrix operating on Selling scalars (expressed in space S6) is derived, and the particular S6matrices for the centered Delone types are listed. (Note: in his later publications, Boris Delaunay used the Russian version of his surname, Delone.)

The post Conservators challenged by contemporary artworks at the Hirshhorn Museum appeared first on Smithsonian Insider.

What determines the variety of trees in a tropical forest? Is it the seed size? Perhaps seed-hungry animals? And what happens to forests that are being drastically changed by humans? Smithsonian Tropical Research Center Botanist, Helene Muller Landau, talks about her attempt to find answers to these questions.

The post Meet Our Scientist: Helene Muller Landau – Tropical Forest Science appeared first on Smithsonian Insider.

Smithsonian Scientist Helen James dives into dormant Hawaiian volcanoes to find bird fossils. Her work to identify these species (some new species, some extinct) helps us learn about the past--specifically, how humans might have caused the extinction of certain bird species.

The post Meet Our Scientist–Helen James dives into dormant Hawaiian volcanoes to find bird fossils appeared first on Smithsonian Insider.

The post Conrad Labandiera, Smithsonian palentologist, studies fossils to learn how insects got along before flowering plants arrived appeared first on Smithsonian Insider.

Silent black & white archival film clip from "Japan: Promotional and Theatrical Footage, ca. 1927". The full film, which is 17 minutes long, includes segments from what are believed to be a theatrical film, a promotional film and, possibly, amateur film - all of unknown origin.

The post Geisha Hairstyling, ca. 1927, a silent black & white archival film clip from the Smithsonian’s Human Studies Film Archives appeared first on Smithsonian Insider.

Monday, April 30 marks planetary geologist Dr. Ellen Stofan’s first day as the new John and Adrienne Mars Director of the National Air and Space […]

The post Ellen Stofan leads Air and Space Museum appeared first on Smithsonian Insider.

Ancient pollen and charcoal preserved in deeply buried sediments in Egypt’s Nile Delta document the region’s ancient droughts and fires, including a huge drought 4,200 years ago associated with the demise of Egypt’s Old Kingdom.

The post Fossil pollen used to augment climate record of Egypt’s Nile Delta appeared first on Smithsonian Insider.

Smooth and shiny, the tough body of the South African beetle Pedinorrhina trivittata, a flower eater, appears to be a non-inviting surface for pollen grains […]

The post Caught on camera: Despite hard shells pollen sticks to South African beetles appeared first on Smithsonian Insider.

Mexico is the fourth largest honey producer and fifth largest honey exporter in the world. A Smithsonian researcher and colleagues helped rural farmers in Mexico […]

The post Genetically modified soybean pollen threatens Mexican honey sales appeared first on Smithsonian Insider.

Unless you’ve been living under a rock for the last few years, you’ve doubtless caught at least a passing reference to the plight of the […]

The post Discovery: Rising CO2 depletes pollen’s nutritional potency, bees suffer appeared first on Smithsonian Insider.

Named for Charles Darwin, the only known specimen of a newly discovered beetle, Darwinylus marcosi, died in a sticky battle in a gob of tree […]

The post Beetle and pollen trapped in 105 million-year-old amber reveal fourth major pollination mode in mid-Mesozoic appeared first on Smithsonian Insider.

Attempting to display the contents of an HDF5 file containing fixed-length UTF-8 encoded strings results in an unexpected error in MATLAB.

For example, the following code

  h5disp('myHDF5FileWithFixedLenUTF8Strings.h5')

returns this error:

Error using h5infoc
UTF-8 encoding is only supported for variable length strings.

Error in h5info (line 108)
hinfo = h5infoc(filename,location, useUtf8);

Error in h5disp>display_hdf5 (line 121)
hinfo = h5info(options.Filename,options.Location);

Error in h5disp (line 99)
display_hdf5(options);

A Landau theory for the wurtzite-based heterovalent ternary semiconductor ZnSnN2 is developed and a first-order reconstructive phase transition is proposed as the cause of observed crystal structure disorder. The model infers that the phase transition is paraelectric to antiferroelectric.

(The Paypers) American Express (Amex) has sent a data breach notification to a group of its...

Focused attention by world leaders is needed to address the substantial challenges posed by disposal of spent nuclear fuel from reactors and high-level radioactive waste from processing such fuel for military or energy purposes.

Representatives from academies and research organizations around the world sent messages of condolence and support to members, officials and staff of the U.S. National Academies in the wake of terrorist attacks on the World Trade Center and the Pentagon. The following are excerpts from some of these messages.

To ensure that minority students who are poorly prepared for school are not assigned to special education for that reason, educators should be required to first provide them with high-quality instruction and social support in a general education classroom before making a determination that special education is needed.

As the recent spread of West Nile virus and the anthrax scare of 2001 dramatically illustrate, America faces a variety of new health challenges in the 21st century, along with a number of persistent problems, such as racial disparities in health status and care delivery.

The role of guns in U.S. society is a subject of intense policy debate and disagreement.

The U.S. National Academy of Engineering (NAE) today announced the grand challenges for engineering in the 21st century. A diverse committee of experts from around the world, convened at the request of the U.S. National Science Foundation, revealed 14 challenges that, if met, would improve how we live.

Increasing the minimum age of legal access (MLA) to tobacco products will prevent or delay initiation of tobacco use by adolescents and young adults, particularly those ages 15 to 17, and improve the health of Americans across the lifespan, says a new report from the Institute of Medicine.