The title mol­ecular salt, (C7H11N2)2[Hg2Cl6], crystallizes with two 4-(di­methyl­amino)­pyridinium cations (A and B) and two half hexa­chlorido­dimercurate(II) anions in the asymmetric unit. The organic cations exhibit essentially the same features with an almost planar pyridyl ring (r.m.s. deviations of 0.0028 and 0.0109 Å), which forms an inclined dihedral angle with the dimethyamino group [3.06 (1) and 1.61 (1)°, respectively]. The di­methyl­amino groups in the two cations are planar, and the C—N bond lengths are shorter than that in 4-(di­methyl­amino)­pyridine. In the crystal, mixed cation–anion layers lying parallel to the (010) plane are formed through N—H⋯Cl hydrogen bonds and adjacent layers are linked by C—H⋯Cl hydrogen bonds, forming a three-dimensional network. The analyses of the calculated Hirshfeld surfaces confirm the relevance of the above inter­molecular inter­actions, but also serve to further differentiate the weaker inter­molecular inter­actions formed by the organic cations and inorganic anions, such as π–π and Cl⋯Cl inter­actions. The powder XRD data confirms the phase purity of the crystalline sample. Furthermore, the vibrational absorption bands were identified by IR spectroscopy and the optical properties were studied by using optical UV–visible absorption spectroscopy.

The asymmetric unit of the title com­pound, catena-poly[[[(perchlorato-κO)copper(II)]-μ-3-(3-carb­oxy­prop­yl)-1,5,8,12-tetra­aza-3-azonia­cyclo­tetra­decane-κ4N1,N5,N8,N12] bis­(per­chlorate)], {[Cu(C13H30N5O2)(ClO4)](ClO4)2}n, (I), consists of a macrocyclic cation, one coordinated per­chlorate anion and two per­chlorate ions as counter-anions. The metal ion is coordinated in a tetra­gonally distorted octa­hedral geometry by the four secondary N atoms of the macrocyclic ligand, the mutually trans O atoms of the per­chlorate anion and the carbonyl O atom of the protonated carb­oxy­lic acid group of a neighbouring cation. The average equatorial Cu—N bond lengths [2.01 (6) Å] are significantly shorter than the axial Cu—O bond lengths [2.379 (8) Å for carboxyl­ate and average 2.62 (7) Å for disordered per­chlorate]. The coordinated macrocyclic ligand in (I) adopts the most energetically favourable trans-III conformation with an equatorial orientation of the substituent at the protonated distal 3-position N atom in a six-membered chelate ring. The coordination of the carb­oxy­lic acid group of the cation to a neighbouring com­plex unit results in the formation of infinite chains running along the b-axis direction, which are cross­linked by N—H⋯O hydrogen bonds between the secondary amine groups of the macrocycle and O atoms of the per­chlorate counter-anions to form sheets lying parallel to the (001) plane. Additionally, the extended structure of (I) is consolidated by numerous intra- and interchain C—H⋯O contacts.

A new pseudopolymorph of dodeca­chloro­penta­silane, namely a benzene monosolvate, Si5Cl12·C6H6, is described. There are two half mol­ecules of each kind in the asymmetric unit. Both Si5Cl12 mol­ecules are completed by crystallographic twofold symmetry. One of the benzene mol­ecules is located on a twofold rotation axis with two C—H groups located on this rotation axis. The second benzene mol­ecule has all atoms on a general position: it is disordered over two equally occupied orientations. No directional inter­actions beyond normal van der Waals contacts occur in the crystal.

The crystal structure of title salt, C14H36N44+·2ClO4−·2Cl−, has been determined using synchrotron radiation at 220 K. The structure determination reveals that protonation has occurred at all four amine N atoms. The asymmetric unit contains one half-cation (completed by crystallographic inversion symmetry), one perchlorate anion and one chloride anion. A distortion of the perchlorate anion is due to its involvement in hydrogen-bonding inter­actions with the cations. The crystal structure is consolidated by inter­molecular hydrogen bonds involving the 1,4,8,11-tetra­methyl-1,4,8,11-tetra­azonia­cyclo­tetra­decane N—H and C—H groups as donor groups, and the O atoms of the perchlorate and chloride anion as acceptor groups, giving rise to a three-dimensional network.

The title pyrazine dicarboxamide ligand, N2,N3-bis­(quinolin-8-yl)pyrazine-2,3-dicarboxamide (H2L1), C24H16N6O2, has a twisted conformation with the outer quinoline groups being inclined to the central pyrazine ring by 9.00 (6) and 78.67 (5)°, and by 79.94 (4)° to each other. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming layers parallel to the (10overline{1}) plane, which are in turn linked by offset π–π inter­actions [inter­centroid distances 3.4779 (9) and 3.6526 (8) Å], forming a supra­molecular three-dimensional structure. Reaction of the ligand H2L1 with Cu(ClO4)2 in aceto­nitrile leads to the formation of the binuclear complex, [μ-(3-{hy­droxy[(quinolin-8-yl)imino]­meth­yl}pyrazin-2-yl)[(quinolin-8-yl)imino]­methano­lato]bis­[diaceto­nitrile­copper(II)] tris­(per­chlor­ate) aceto­nitrile disolvate, [Cu2(C24H15N6O2)(CH3CN)4](ClO4)3·2CH3CN or [Cu2(HL1−)(CH3CN)4](ClO4)3·2CH3CN (I). In the cation of complex I, the ligand coordinates to the copper(II) atoms in a bis-tridentate fashion. A resonance-assisted O—H⋯O hydrogen bond is present in the ligand; the position of this H atom was located in a difference-Fourier map. Both copper(II) atoms are fivefold coordinate, being ligated by three N atoms of the ligand and by the N atoms of two aceto­nitrile mol­ecules. The first copper atom has a perfect square-pyramidal geometry while the second copper atom has a distorted shape. In the crystal, the cation and perchlorate anions are linked by a number of C—H⋯O hydrogen bonds, forming a supra­molecular three-dimensional structure.

The title compound, C24H18FNO3, crystallizes in the monoclinic centrosymmetric space group P21/n and its mol­ecular conformation is stabilized via C—H⋯O intra­molecular inter­actions. The supra­molecular network mainly comprises C—H⋯O, C—H⋯F and C—H⋯π inter­actions, which contribute towards the formation of the crystal structure. The different inter­molecular inter­actions have been further analysed via Hirshfeld surface analysis and fingerprint plots.

Theoretically, crystals with supercells exist at a unique crossroads where they can be considered as either a large unit cell with closely spaced reflections in reciprocal space or a higher dimensional superspace with a modulation that is commensurate with the supercell. In the latter case, the structure would be defined as an average structure with functions representing a modulation to determine the atomic location in 3D space. Here, a model protein structure and simulated diffraction data were used to investigate the possibility of solving a real incommensurately modulated protein crystal using a supercell approximation. In this way, the answer was known and the refinement method could be tested. Firstly, an average structure was solved by using the `main' reflections, which represent the subset of the reflections that belong to the subcell and in general are more intense than the `satellite' reflections. The average structure was then expanded to create a supercell and refined using all of the reflections. Surprisingly, the refined solution did not match the expected solution, even though the statistics were excellent. Interestingly, the corresponding superspace group had multiple 3D daughter supercell space groups as possibilities, and it was one of the alternate daughter space groups that the refinement locked in on. The lessons learned here will be applied to a real incommensurately modulated profilin–actin crystal that has the same superspace group.

The program Mercury, developed at the Cambridge Crystallographic Data Centre, was originally designed primarily as a crystal structure visualization tool. Over the years the fields and scientific communities of chemical crystallography and crystal engineering have developed to require more advanced structural analysis software. Mercury has evolved alongside these scientific communities and is now a powerful analysis, design and prediction platform which goes a lot further than simple structure visualization.

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

A new bacterial genome sequence could help researchers solve a mystery as to how microorganisms produce a highly toxic form of mercury.

The post New bacteria genome may help solve mystery of how methylmercury is made appeared first on Smithsonian Insider.

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 […]

The post SERC sedge grass experiment mimics predicted global-change scenario appeared first on Smithsonian Insider.

Microbes that live in rice paddies, northern peat bogs and other previously unexpected environments are among the bacteria that can generate highly toxic methylmercury, researchers […]

The post Toxic methylmercury-producing microbes more widespread than realized appeared first on Smithsonian Insider.

Hot spots of mercury pollution in aquatic sediments and soils can contaminate local food webs and threaten ecosystems, but cleaning them up can be expensive […]

The post Toxicity of mercury hot spots can be reduced with application of activated carbon, researchers discover appeared first on Smithsonian Insider.

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.

Here’s some good news that should hit you in the gut. A team of scientists searching thousands of environments for bacteria that produce the deadly […]

The post Survey pinpoints where toxic mercury accumulates in world environments appeared first on Smithsonian Insider.

The biological processes related to protein homeostasis in Mycobacterium tuberculosis, the etiologic agent of tuberculosis, have recently been established as critical pathways for therapeutic intervention. Proteins of particular interest are ClpC1 and the ClpC1–ClpP1–ClpP2 proteasome complex. The structure of the potent antituberculosis macrocyclic depsipeptide ecumicin complexed with the N-terminal domain of ClpC1 (ClpC1-NTD) is presented here. Crystals of the ClpC1-NTD–ecumicin complex were monoclinic (unit-cell parameters a = 80.0, b = 130.0, c = 112.0 Å, β = 90.07°; space group P21; 12 complexes per asymmetric unit) and diffracted to 2.5 Å resolution. The structure was solved by molecular replacement using the self-rotation function to resolve space-group ambiguities. The new structure of the ecumicin complex showed a unique 1:2 (target:ligand) stoichiometry exploiting the intramolecular dyad in the α-helical fold of the target N-terminal domain. The structure of the ecumicin complex unveiled extensive interactions in the uniquely extended N-terminus, a critical binding site for the known cyclopeptide complexes. This structure, in comparison with the previously reported rufomycin I complex, revealed unique features that could be relevant for understanding the mechanism of action of these potential antituberculosis drug leads. Comparison of the ecumicin complex and the ClpC1-NTD-L92S/L96P double-mutant structure with the available structures of rufomycin I and cyclomarin A complexes revealed a range of conformational changes available to this small N-terminal helical domain and the minor helical alterations involved in the antibiotic-resistance mechanism. The different modes of binding and structural alterations could be related to distinct modes of action.

Images obtained by NASA’s MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft during the low-altitude orbital phase of the mission have revealed previously undetected […]

The post Mercury Joins Earth As Tectonically Active Planet appeared first on Smithsonian Insider.

The post What will invasive round goby fish do to Great Lakes streams? Join SERC post doc Matt Kornis and find out. appeared first on Smithsonian Insider.

Smithsonian biologist Cindy Gilmour describes where mercury pollution comes from, how it morphs into the neurotoxin methylmercury, and if we’re finally starting to solve the […]

The post Ecosystems on the Edge: Tracking Mercury appeared first on Smithsonian Insider.

Residents of the southeastern United States might occasionally come across an oddity along a barbed-wire fence: a series of insects, mice or even small birds […]

The post Tiny, fierce and disappearing: breeding program aims to help the loggerhead shrike appeared first on Smithsonian Insider.

Fort Pierce, Fla. – Fall in southern Florida is festival season: when the weather stops being oppressively hot and 70 degrees is positively autumnal.  On […]

The post Annual Smithsonian-led science festival draws crowds in Fort Pierce, Florida appeared first on Smithsonian Insider.

This free report highlights the main facts, numbers and trends of the Russian ecommerce and e-payments markets in an international perspective.

The new Cross-Border Payments and Commerce Report 2019 – 2020 depicts the major trends driving growth in cross-border payments, cross-border commerce, and marketplaces.

A cosplay gathering in the Anaheim Convention Center's Grand Plaza during WonderCon Anaheim 2014.; Credit: Kevin Green/SDCC

For all the sad comic book and pop culture fans who weren't able to get tickets to San Diego Comic-Con, we've got good news for you: They run another convention, and it's closer to Los Angeles. Their little brother WonderCon Anaheim has been growing, with some comparing it to the Comic-Con of old — before it got way too crowded. It's this Friday through Sunday, April 3-5. They're starting to have big stars and lots of great panels, so if you want to get your geek heart sated, here are some of the events you won't want to miss.

Warner Bros. Presentation: San Andreas, Mad Max: Fury Road

San Andreas trailer

The most highly anticipated event at this weekend's convention, Warner Brothers is putting on a special presentation with footage from these two upcoming action films. They haven't announced which stars will be on hand, but these panels often surprise with star power, so you may get a visit from stars like "San Andreas's" Dwayne "The Rock" Johnson or "Mad Max: Fury Road's" Tom Hardy or Charlize Theron. At the Comic-Con panel last year for the "Mad Max" flick, the director talked in detail about the film, so you'll probably at least get his take on the franchise and its resurrection.

DC Comics TV shows: The Flash, Gotham, iZombie

The Flash trailer

While Marvel has been dominant on the big screen, DC has put out a diverse slate of TV shows, with "The Flash" being the biggest hit among them. It's among those getting a spotlight at WonderCon, with creators and stars dishing on the programs that have captured the imaginations of TV fans and comic fans alike. All three shows are also getting special video presentations, likely showing clips of what you can expect the rest of this season. And in case you didn't already know, "iZombie" comes from "Veronica Mars" creator Rob Thomas, so come find out about his latest project.

World Premiere: Batman vs. Robin

Batman vs. Robin trailer

It's become a tradition at both WonderCon and San Diego Comic-Con for DC Comics to debut their latest animated movie, and the new one is based on the critically acclaimed "Court of Owls" storyline by writer Scott Snyder. (Be sure to check out our previous interviews with Snyder — he's even an NPR fan.) The original story is based on how Batman thinks he knows everything there is to know about Gotham City and faces the discovery that there are deep secrets about the city that he had no idea about, and the film also emphasizes him fighting his son Damian.

Sing-alongs: Dr. Horrible & Batman's The Music Meister

Batman: The Brave and the Bold: Drives Us Bats

People go to comic conventions to geek out, and what's geekier than a good old-fashioned singalong? In addition to one for geek god Joss Whedon's much loved Web series "Dr. Horrible's Sing-Along Blog," they're also doing one for the musical episode of animated series "Batman: The Brave and the Bold" — which, just like "Dr. Horrible," features singing by the one and only Neil Patrick Harris. In the Batman cartoon, he plays the Music Meister, a Batman villain who makes both heroes and villains sing, as he drops some tunes of his own.

Superman: The Richard Donner Years Celebrity Super Reunion

Superman: The flying sequence

There's a reunion of stars from the first two of the classic Christopher Reeve Superman movies, including Lois Lane herself, Margot Kidder. You can also see the actors who played characters like Jimmy Olsen, several of the villains and more, as well as two of the producers. Find out what you don't know about the movie that broke ground when it came to depicting flight on-screen and, like the ads promised, made you believe a man could fly.

TV writing panels

Two panels will give you a peek into the world of the writers who write some of the hottest shows on TV: "TV Guide Magazine's Fan Favorites Showrunners" and "Inside The Writers' Room: Earth's Mightiest Writers Re-Assemble Redux." The first of those includes legendary TV showrunners like Dan Harmon of "Community" and the minds behind shows including "Orphan Black," "The Goldbergs" and more. Meanwhile, at the writers room panel, you'll get writers who've worked on shows like "Lost," "Firefly," "Heroes," "The Big Bang Theory," "Agent Carter" and more.

Fan culture programming track

This includes a lot of different panels, but it's a sign of the way fandom is shifting — it's a lifestyle that's far more diverse than it used to be, with a lot more gender parity. This track includes panels on topics like body confidence in cosplay, fashion, fitness, race and more. See what sparks your interest and might invite you into having an identity as a fan being a bigger part of your life while not letting anyone make you feel excluded.

There's so much more, like Will Forte doing a panel promoting his new show "The Last Man On Earth," the annual cosplay masquerade and so much more. Tickets are sold out for Saturday, but at press time, tickets were still available for both Friday and Sunday at WonderCon.

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

(The Paypers) Forter has released the seventh edition of its Fraud Attack Index, tracking shifting behaviours...

(The Paypers) Ecommerce Foundation has surveyed 5.200 consumers from 42 countries to better...

(The Paypers) SnapPay has announced the availability of facial recognition payment technology for North...

As the Covid-19 pandemic spreads, commercial payments volumes have declined across the globe due to...

While the U.S. Environmental Protection Agencys guideline for protecting the public from a toxic form of mercury is justifiable based on the latest scientific evidence, some children of women who consume large amounts of fish and seafood during pregnancy may be at special risk of neurological problems.

Rates of physical and sexual abuse of children have declined over the last 20 years, but for reasons not fully understood, says a new report from the Institute of Medicine. Yet, reports of psychological and emotional child abuse have risen in the same period, and data vary significantly as to whether child neglect is increasing, decreasing, or remaining constant.

One of the nation’s largest surveys of crime victims is likely undercounting incidences of rape and sexual assault, making it difficult to ensure that adequate law enforcement resources and support services are available for victims, says a new report by the National Research Council.

Cardiac arrest strikes almost 600,000 people each year, killing the vast majority of those individuals, says a new report from the Institute of Medicine. Every year in the U.S., approximately 395,000 cases of cardiac arrest occur outside of a hospital setting, in which less than 6 percent survive.

Across the current military and civilian trauma care systems, the quality of trauma care varies greatly depending on when and where an individual is injured, placing lives unnecessarily at risk, says a new report from the National Academies of Sciences, Engineering, and Medicine.

Improved understanding of the coupled natural-human coastal system will help promote resilience of coastal communities and ecosystems under rapidly changing environmental conditions and support informed decision-making, says a new report from the National Academies of Sciences, Engineering, and Medicine.

A new report from the National Academies of Sciences, Engineering, and Medicine outlines a research agenda for improving the commercial viability of technologies that turn greenhouse gases from the burning of fossil fuels into useful products such as fuels, construction materials, and chemicals.

The supercritical water oxidation (SCWO) system is a secondary waste processing reactor of the Blue Grass Chemical Agent Destruction Pilot Plant (BGCAPP). It is perhaps second in importance behind the agent neutralization reactors, which perform base hydrolysis of chemical warfare agents stored at the Blue Grass Army Depot.

Argentina-based fintech Mercado Pago has announced it will now be possible to share...

India-based merchant payment and lending service provider BharatPe has announced disbursing funds...

Opah fish are hauled onto a dock for sale last week in San Diego. Fishermen coming home to California after weeks at sea are finding strict anti-coronavirus measures, and nowhere to sell their catch.; Credit: Gregory Bull/AP

Commercial fishermen in the U.S. who have already faced challenges in recent years to make it in an increasingly globalized and regulated industry, are now struggling to find customers during the coronavirus crisis.

"This is totally unprecedented. This is the biggest crisis to hit the fishing industry ever, no question about that," Noah Oppenheim, executive director of The Pacific Coast Federation of Fishermen's Associations told NPR in a phone interview. The federation is a trade association representing commercial fishermen along the West Coast.

On Tuesday, seafood industry leaders, processors and fishermen sent a letter to House and Senate leaders requesting $4 billion in aid for the industry.

The closings of restaurants due to the coronavirus pandemic has hit commercial fishermen particularly hard.

An estimated 50% to 60% of wild seafood caught in the U.S. is exported, says Oppenheim. Those international markets have dried up. He says, of the seafood that's not exported, around 80% of that is sold to restaurants.

"Both of those sectors of the seafood economy are largely nonfunctional at the moment, so we're going to have to make up for approximately 90% of our markets ... through either new supply pipelines or new sets of customers."

Jerid Rold, a fishermen in Moss Landing, Calif., tells NPR, he's been out of work for a month, since South Korea stopped taking imports of hagfish. Further damaging profits, Dungeness crab prices on the West Coast have fallen from up to $7 dollars a pound to $2, says Oppenheim.

In Eureka, Calif., "there are no buyers purchasing products at the harbor there. You can't move the Dungeness crab out of the Humboldt bay," Oppenheim said. "It's actually extraordinary how similar these impacts are playing out across the country. They are palpable, they are profound and they are severe."

On the North Atlantic coast, Sam Rosen, a 30-year-old lobsterman based in Vinalhaven, Maine, said he and others are "selling lobster for amounts they shouldn't be sold for."

That's been close to $2.50 a pound, compared to a usual $10 a pound this time of year, Rosen said.

"It's definitely a shock to the system," Rosen said. "This is uncharted territory right now. I don't think anyone thought it was going to be as bad as it's getting."

If aid isn't provided to fishermen soon, "I think we could see hundreds to thousands of fishermen leave the industry nationwide," Oppenheim said.

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

In L.A., community leaders are working to prevent an undercount of Asian Angelenos. ; Credit: via NPR

The 2020 Census kicks off in a matter of weeks. Census officials say Asian immigrants are “hard-to-count” because many have limited English and distrust government. 

Leo Moon is learning about the census with friends at a city-led workshop in Koreatown. He didn’t fill out the form in 2010, mostly because he didn’t want the government knowing he’s undocumented. But Moon says he’ll take part next year because the census determines how much funding and representation people get.  

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

Qualys BrowserCheck is a cloud service that makes sure your browser and installed plugins are all up-to-date so that you not affected by security vulnerabilities in outdated browser technology. [...]

In this file photo, job seekers line up to enter Choice Career Fair at the Los Angeles Convention Center on December 1, 2010 in Los Angeles, California. Overall, the number of unemployed Californians ticked up by 1,000 over the month to nearly 1.4 million for August 2014, but the rate remained unchanged, at 7.4 percent. The national unemployment rate is down to 6.1 percent.; Credit: Kevork Djansezian/Getty Images

California's unemployment rate is unchanged for a third month, holding at 7.4 percent in August.

The California Employment Development Department reported Friday that the state added 44,200 nonfarm jobs during the month, bringing the state total to 15.5 million in August.

Last month's gains mean the state has added 1.4 million jobs since February 2010, when the jobless number hit a peak of 12.4 percent.

Overall, the number of unemployed Californians ticked up by 1,000 over the month to nearly 1.4 million. The national unemployment rate is down to 6.1 percent.

Construction posted the largest increase over the month, adding 13,600 jobs. Manufacturing, financial activities, business services, education, health, leisure and government all added jobs in August.

Trade, transportation and utilities, along with information, posted job losses of 8,300.