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.

Hydrogen is present in almost all of the molecules in living things. It is very reactive and forms bonds with most of the elements, terminating their valences and enhancing their chemistry. X-ray diffraction is the most common method for structure determination. It depends on scattering of X-rays from electron density, which means the single electron of hydrogen is difficult to detect. Generally, neutron diffraction data are used to determine the accurate position of hydrogen atoms. However, the requirement for good quality single crystals, costly maintenance and the limited number of neutron diffraction facilities means that these kind of results are rarely available. Here it is shown that the use of Transferable Aspherical Atom Model (TAAM) instead of Independent Atom Model (IAM) in routine structure refinement with X-ray data is another possible solution which largely improves the precision and accuracy of X—H bond lengths and makes them comparable to averaged neutron bond lengths. TAAM, built from a pseudoatom databank, was used to determine the X—H bond lengths on 75 data sets for organic molecule crystals. TAAM parametrizations available in the modified University of Buffalo Databank (UBDB) of pseudoatoms applied through the DiSCaMB software library were used. The averaged bond lengths determined by TAAM refinements with X-ray diffraction data of atomic resolution (dmin ≤ 0.83 Å) showed very good agreement with neutron data, mostly within one single sample standard deviation, much like Hirshfeld atom refinement (HAR). Atomic displacements for both hydrogen and non-hydrogen atoms obtained from the refinements systematically differed from IAM results. Overall TAAM gave better fits to experimental data of standard resolution compared to IAM. The research was accompanied with development of software aimed at providing user-friendly tools to use aspherical atom models in refinement of organic molecules at speeds comparable to routine refinements based on spherical atom model.

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.

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

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.

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.

Today, Wednesday, May 25, astronomers unveiled the most complete 3-D map of the local universe (out to a distance of 380 million light-years) ever created. Taking more than 10 years to complete, the 2MASS Redshift Survey (2MRS) also is notable for extending closer to the Galactic plane than previous surveys – a region that’s generally obscured by dust.

The post Astronomers unveil the most complete 3-D map of the local universe appeared first on Smithsonian Insider.

A local supernova factory has recently started production, according to a wealth of new data from NASA's Chandra X-ray Observatory on the Carina Nebula.

The post The Carina Nebula, a local supernova factory, is ramping up production appeared first on Smithsonian Insider.

"I nearly fell out of my chair at the telescope when I saw one star change its speed by a staggering 750 miles per second in just a few minutes," said Smithsonian astronomer Warren Brown, lead author of the paper reporting the find.

The post Astronomers find two white-dwarf stars locked in death spiral appeared first on Smithsonian Insider.

The Life and Morals of Jesus of Nazareth, more commonly known as the Jefferson bible, is a volume created by Thomas Jefferson containing passages he […]

The post Unlocking the mysteries of Jefferson’s bible with high-tech analysis and microscopic testing appeared first on Smithsonian Insider.

These green crabs have been doing a number on native shellfish. They eat a lot of clams. And they're a very cosmopolitan species—they've now spread all over, to places as far afield as the West Coast of the U.S. and South Africa.

The post Location matters: For invasive aquatic species, it’s better to start upstream appeared first on Smithsonian Insider.

Halocoryza acapulcana Whitehead (Acapulco Saline Catarrh Beetle), described in 1966 by Donald R. Whitehead. This image is from a recent paper by Terry L. Erwin, […]

The post Halocoryza acapulcana Whitehead appeared first on Smithsonian Insider.

The fastest wind ever discovered blowing off a disk around a stellar-mass black hole has been observed by a team of astronomers using NASA’s Chandra X-ray Observatory.

The post Chandra X-ray Observatory clocks stellar wind at 20 million mph appeared first on Smithsonian Insider.

Last summer and this spring Boy Scout Arthur Carlton-Jones (shown here), working in conjunction with researchers at the Smithsonian Environmental Research Center in Edgewater, Md., […]

The post Save your local fishing hole appeared first on Smithsonian Insider.

Smithsonian scientists and partners find that technique meant to keep animals and humans safe has opposite effects.

The post Relocating elephants fails to decrease human–wildlife conflict 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.

Based on a treasure trove of recent discoveries, astronomers now know that planets are remarkably plentiful in our galaxy and may be common throughout the […]

The post Dust trap around distant star may unlock mystery as to how planets form appeared first on Smithsonian Insider.

The Smithsonian’s National Museum of Natural History, in partnership with the National Human Genome Research Institute of the National Institutes of Health, has opened  “Genome: […]

The post Genome: Unlocking Life’s Code appeared first on Smithsonian Insider.

The Mortlock Islands flying fox, a large, breadfruit-eating bat native to a few remote and tiny Pacific islands, has long been regarded as one of […]

The post Scientists shine light on world’s least-studied bat: Mortlock Islands flying fox appeared first on Smithsonian Insider.

Unlocking the mysteries of animal migration through precise, near real-time tracking can solve major conservation challenges and transform wildlife science worldwide. For the past year, […]

The post New project to unlock migration mysteries from air appeared first on Smithsonian Insider.

Paddling the remote oxbow lakes and bayous of the White River National Wildlife Refuge in Arkansas, the team of scientists was seeking proof of a […]

The post Nest discovery turns back the clock to days of Daniel Boone and Colonial America appeared first on Smithsonian Insider.

The largest fully preserved great ape collection in the world is about to make its online debut.

The post Unlocking secrets–technology allows scientists to peer inside great apes appeared first on Smithsonian Insider.

Astronomers announced today that they have found eight new planets in the “Goldilocks” zone of their stars, orbiting at a distance where liquid water can […]

The post Eight New Planets Found in “Goldilocks” Zone appeared first on Smithsonian Insider.

Four years after conservationists relocated 570 desert tortoises (Gopherus agassizii) in California from a threatened habitat to a new nearby location, the tortoises outwardly appeared […]

The post Smithsonian Study shows relocated desert tortoises reproduce at lower rate appeared first on Smithsonian Insider.

In a new study in which one of humankind’s most high-tech tools was used to analyze one of its most primitive, scientists have uncovered evidence […]

The post Laser beams unveil secrets locked inside primitive stone spear points appeared first on Smithsonian Insider.

In conflicts between predators and prey, speed is a decided advantage, and evolution has given the trap-jaw ant a distinct advantage with spring-loaded jaws that […]

The post Locked and loaded: unique trigger design fires this ant’s snapping jaws appeared first on Smithsonian Insider.

Astronomers had a mystery on their hands. No matter where they looked, from inside the Milky Way to distant galaxies, they observed a puzzling glow […]

The post GBT Detection Unlocks Exploration of ‘Aromatic’ Interstellar Chemistry appeared first on Smithsonian Insider.

Little to nothing is known about how and where a small European songbird called the bluethroat spends much of the year. Now, Smithsonian scientists have […]

The post Scientists track a mysterious songbird using tiny backpack locators appeared first on Smithsonian Insider.

Victor J. F. Kitano, Yoko Ohyama, Chiyomi Hayashida, Junta Ito, Mari Okayasu, Takuya Sato, Toru Ogasawara, Maki Tsujita, Akemi Kakino, Jun Shimada, Tatsuya Sawamura, and Yoshiyuki Hakeda

Osteoporosis is associated with vessel diseases attributed to hyperlipidemia, and bone resorption by multinucleated osteoclasts is related to lipid metabolism. In this study, we generated low-density lipoprotein receptor (LDLR)/lectin-like oxidized LDL receptor-1 (LOX-1) double knockout (dKO) mice. We found that, like LDLR single KO (sKO), LDLR/LOX-1 dKO impaired cell-cell fusion of osteoclast-like cells (OCLs). LDLR/LOX-1 dKO and LDLR sKO preosteoclasts exhibited decreased uptake of LDL. The cell surface cholesterol levels of both LDLR/LOX-1 dKO and LDLR sKO osteoclasts were lower than the levels of wild-type OCLs. Additionally, the amount of phosphatidylethanolamine (PE) on the cell surface was attenuated in LDLR/LOX-1 dKO and LDLR sKO pre-OCLs, while the PE distribution in wild-type OCLs was concentrated on the filopodia in contact with neighboring cells. Abrogation of the ATP binding cassette G1 (ABCG1) transporter, which transfers PE to the cell surface, caused decreased PE translocation to the cell surface and subsequent cell-cell fusion. The findings of this study indicate the involvement of a novel cascade (LDLR~ABCG1~PE translocation to cell surface~cell-cell fusion) in multinucleation of OCLs.

M. Pinar and M. A. Penalva

TRAnsport Protein Particle (TRAPP) complexes regulate membrane traffic. TRAPPII and TRAPPIII share a core hetero-heptamer, also denoted TRAPPI. In fungi TRAPPIII and TRAPPII mediate GDP exchange on RAB1 and RAB11, respectively, regulating traffic across the Golgi, with TRAPPIII also activating RAB1 in autophagosomes. Our finding that Aspergillus nidulans TRAPPII can be assembled by addition of a TRAPPII-specific subcomplex onto core TRAPP prompted us to investigate the possibility that TRAPPI/TRAPPIII already residing in the Golgi matures into TRAPPII to determine a RAB1-to-RAB11 conversion as Golgi cisternae progress from early Golgi to TGN identity. By time-resolved microscopy we determine that the TRAPPII reporter Trs120/TRAPPC9 is recruited to existing TGN cisternae slightly before RAB11 arrives, and resides for~45 sec on them before cisternae tear off into RAB11 secretory carriers. Notably, the core TRAPP reporter Bet3/TRAPPC3 was not detectable in early Golgi cisternae, being instead recruited to TGN cisternae simultaneously with Trs120/TRAPPC9, indicating en bloc recruitment of TRAPPII to the Golgi and arguing strongly against the TRAPP maturation model.

Juan Martin D'Ambrosio, Veronique Albanese, Nicolas-Frederic Lipp, Lucile Fleuriot, Delphine Debayle, Guillaume Drin, and Alenka Copic

Osh6 and Osh7 are lipid transfer proteins (LTPs) that move phosphatidylserine (PS) from the endoplasmic reticulum (ER) to the plasma membrane (PM). High PS level at the PM is key for many cellular functions. Intriguingly, Osh6/7 localize to ER-PM contact sites, although they lack membrane-targeting motifs, in contrast to multidomain LTPs that both bridge membranes and convey lipids. We show that Osh6 localization to contact sites depends on its interaction with the cytosolic tail of the ER-PM tether Ist2, a homologue of TMEM16 proteins. We identify a motif in the Ist2 tail, conserved in yeasts, as the Osh6-binding region, and we map an Ist2-binding surface on Osh6. Mutations in the Ist2 tail phenocopy osh6 osh7 deletion: they decrease cellular PS levels, and block PS transport to the PM. Our study unveils an unexpected partnership between a TMEM16-like protein and a soluble LTP, which together mediate lipid transport at contact sites.

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.

The post Learn about the National Zoo’s flamingo flock with keeper Sara Hallager appeared first on Smithsonian Insider.

Simulink might produce an incorrect sorted order for a model that meets all of the following conditions:

• The model contains blocks from the SoC Blockset
• The Signal logging option is selected in the model configuration set
• Signals using asynchronous sample time are configured for logging

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 

An intuitive method is presented for detecting pseudosymmetries in Z' > 1 cases as a complement to well-proven strategies already available in the literature. It is based in the simple idea that the mid-points between equivalent atoms in symmetrically related mol­ecules are disposed according to simple well-known patterns, which are easily recognizable by optical inspection. A number of Z' = 4 cases in the literature are analyzed, which allows some of the potentialities of the method to be revealed.

LAUSD Superintendent Ramon Cortines commented Thursday on teacher contract talks that have been ongoing since July.; Credit: Benjamin Brayfield/KPCC

A budget deficit is preventing the Los Angeles Unified School District from offering teachers more than a 5 percent raise, Superintendent Ramon Cortines said Friday.

"I want some resolution," Cortines told reporters, but he said the district is now projecting a shortfall of $160 million heading into the next school year.

United Teachers Los Angeles, the union representing 31,000 teachers, declared an impasse Thursday in the contract negotiations. The two sides have been bargaining since July.

The teachers haven't had a pay increase in eight years, and their salaries are below that of neighboring districts. 

"You are not going to recruit and retain the quality teachers you need," UTLA President Alex Caputo-Pearl told KPCC's AirTalk this week. The union is seeking an 8.5 percent raise as well as smaller class sizes, more counselors and nurses, and revised teacher evaluations.

Cortines said the district's pay raise offer of 5 percent, retroactive to July 2014, would help make salaries more competitive. But he said the projected deficit is why LAUSD can't afford more.

Projections for the deficit have changed over the months. Last October, it was $365 million; in January, $88 million; and this month, $160 million. 

Teachers union representatives said California schools are receiving more money this year than any time since the recession. Gov. Jerry Brown's Local Control Funding process, which gives local districts more resources for education, is projected to garner the district $240 million more next school year. 

Cortines said he hopes to reach an agreement and he cautioned against any walkout.

"You talk about a budget deficit? It will exacerbate the budget deficit, because parents have other options," Cortines said. "They can go to other schools, private, parochial schools, they can go to charter schools, etc."

Cortines said a mediator is being called into the talks to help resolve the impasse.

The superintendent also repeated his doubts that the district can currently afford to put a computer in the hands of every district student. The program, a key initiative of his predecessor, John Deasy, used bond funds to pay for iPads and other devices.

Cortines said a statement elaborating on his remarks to reporters that "as we are reviewing our lessons learned, there must be a balanced approach to spending bond dollars to buy technology when there are so many brick and mortar and other critical facility needs that must be met."

This content is from Southern California Public Radio. View the original story at SCPR.org.

Immigration benefits the U.S. economy overall and has little negative effect on the income and job opportunities of most native-born Americans, says a new report by a panel of the National Research Council.

The science questions that could be answered by an electron ion collider (EIC) – a very large-scale particle accelerator – are significant to advancing our understanding of the atomic nuclei that make up all visible matter in the universe, says a new report by the National Academies of Sciences, Engineering, and Medicine.