Because researchers do not understand the formation mechanism of cocrystals, the preparation of cocrystals is mostly done by trial and error. This study focuses on the cocrystal formation mechanism to improve the efficiency of cocrystal preparation.

A calculation procedure for X-ray total scattering and the pair distribution function from a crystalline structural model is presented. It allows one to easily and precisely deal with diffraction-angle-dependent parameters such as the atomic form factor and the resolution of the optics.

A detailed theoretical and experimental comparison of dark-field electron holography (DFEH) and high-resolution X-ray diffraction (HRXRD) is performed. Both techniques are being applied to measure elastic strain in an array of transistors and the role of the geometric phase is emphasized.

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.

The structure of the Pseudomonas aeruginosa T6SS PldB immunity protein PA5086 is reported at 1.9 Å resolution. Comparison of PA5086 with its homologs PA5087 and PA5088 showed great similarities in sequence and structure, but vast divergences in electrostatic potential surfaces.

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.

A description and photos of the green-headed tanager (Tangara seledon), a bird native to east-central South America, can be found in the Species of the […]

The post Green-headed Tanager (Tangara seledon) of east-central South America appeared first on Smithsonian Insider.

A new study has revealed information about the way tungara frogs in the tropical rain forest hear, sort, and process sounds which is very similar to the way humans do. The knowledge could be applicable to communication disorders associated with hearing loss and attention deficits or difficulties.

The post Research on tungara frogs may be applicable to hearing loss/attention deficits in humans appeared first on Smithsonian Insider.

Two scientists at the Smithsonian Institution have been honored with the Presidential Early Career Award for Scientists and Engineers for their innovative research and scientific leadership. It is the highest honor bestowed by the U.S. government on science and engineering professionals in the early stages of their independent research careers.

The post President Barack Obama recognizes outstanding scientists at the Smithsonian appeared first on Smithsonian Insider.

Smithsonian Secretary Wayne Clough, left, talks with Carlos Jaramillo, scientist at the Smithsonian Tropical Research Institute in Panama, at a research site near the Panama […]

The post Wayne Clough & Carlos Jaramillo, at a research site near the Panama Canal. appeared first on Smithsonian Insider.

To celebrate its 22nd anniversary in orbit, the Hubble Space Telescope has released a dramatic new image of the star-forming region 30 Doradus, also known […]

The post New image of the star-forming region 30 Doradus, also known as the Tarantula Nebula appeared first on Smithsonian Insider.

One such parasite lurks in Chesapeake Bay: an invasive barnacle that hijacks a mud crab’s reproductive system and impregnates it with parasite larvae—even if the crab is male.

The post Undersea parasite turns male mud crabs female appeared first on Smithsonian Insider.

Ants dominate the earth’s ecosystems and many are voracious predators that use their mandibles and sheer numbers to pin down and tear apart most other […]

The post Carabidae in the colony, seven new beetles that bunk with ants: Q&A with Terry Erwin appeared first on Smithsonian Insider.

The carabid beetle tribe Lachnophorini is the focus of an extensive new study by two Smithsonian entomologists just published in a special issue of the […]

The post New study focuses on carabid beetles appeared first on Smithsonian Insider.

A newly-discovered species of ant supports a controversial theory of species formation. The ant, known to live only under a single eucalyptus tree on the […]

The post Deadbeat ant species branched off as parasite inside its own colony appeared first on Smithsonian Insider.

Have you ever had a pet that seemed just a little bit crazy or odd? Can you be sure that it was in control of […]

The post Crazy eyes and mind control – the power of parasites appeared first on Smithsonian Insider.

The odds of being attacked and castrated by a variety of parasitic flatworms increases for marine horn snails the farther they are found from the […]

The post Parasitic flatworms flout global biodiversity patterns appeared first on Smithsonian Insider.

Through sheer coincidence, two Smithsonian researchers at the National Zoological Park have discovered that 18 percent of the white-tailed deer population in the Eastern United […]

The post Smithsonian study reveals white-tailed deer in eastern U.S. are infected with a malaria parasite appeared first on Smithsonian Insider.

A one-cubic-foot approach to studying biodiversity as showcased in the new Biocube exhibit at the Smithsonian’s National Museum of Natural History has led to the […]

The post New parasitic crab species discovered during Smithsonian Biocube work in Solomon Islands appeared first on Smithsonian Insider.

Fat, toxic and nocturnal, cane toads (Rhinella marina) are abundant today in Hawaii, even though they are South American natives. Released on the Hawaiian Islands […]

The post Two invasive species have Hawaiian reunion after 80-year separation appeared first on Smithsonian Insider.

Aline A. Alves, Heloisa B. Gabriel, Maria J. R. Bezerra, Wanderley de Souza, Sue Vaughan, Narcisa L. Cunha-e-Silva, and Jack D. Sunter

Eukaryotic flagella are complex microtubule based organelles and in many organisms there are extra-axonemal structures present, including the outer dense fibres of mammalian sperm and the paraflagellar rod (PFR) of trypanosomes. Flagellum assembly is a complex process occurring across three main compartments, the cytoplasm, the transition fibre-transition zone, and the flagellum. It begins with translation of protein components, followed by their sorting and trafficking into the flagellum, transport to the assembly site and then incorporation. Flagella are formed from over 500 proteins; the principles governing axonemal component assembly are relatively clear. However, the coordination and sites of extra-axonemal structure assembly processes are less clear.

We have discovered two cytoplasmic proteins in T. brucei that are required for PFR formation, PFR assembly factors 1 and 2. Deletion of either PFR-AF1 or PFR-AF2 dramatically disrupted PFR formation and caused a reduction in the amount of major PFR proteins. The presence of cytoplasmic factors required for PFR formation aligns with the concept of processes occurring across multiple compartments to facilitate axoneme assembly and this is likely a common theme for extra-axonemal structure assembly.

Formed some 250,000 years ago when the Nile River pushed through a low channel near Wadi Tushka, it flooded the eastern Sahara, creating a lake that at its highest level covered more than 42,000 square miles.

The post Ancient megalake discovered beneath Sahara Desert appeared first on Smithsonian Insider.

More than 500 carats of rough diamonds were recently donated to the Department of Mineral Sciences of the Smithsonian’s Natural History Museum by Jewlers Mutual Insurance Co. of Neenah, Wis.

The post 500 carats of rough diamonds donated to Natural History Museum appeared first on Smithsonian Insider.

Under the anomalous transmission condition in the Bragg mode, X-ray interference fringes were observed between two beams with different hyperbolic trajectories in a very weakly bent plane-parallel perfect crystal with negative strain gradient. The origin of the fringes was analysed based on the dynamical theory of diffraction for a distorted crystal. In the reflected beam from the entrance surface, the interference fringes were observed between once- and twice-reflected beams from the back surface. In the transmitted beam from the back surface, the interference fringes were observed between the direct beam and once-reflected beam from the entrance surface. In the emitted beam from the lateral surface, the interference fringes were observed between the beams after different numbers of reflections in the crystal. The multiply reflected beams were formed by a combined result of long propagation length along the beam direction with large divergence of the refracted beams when the strain gradient was negative. The period of these interference fringes was sensitive to very weak strain, of the order of 10−7.

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

Mark Torchin, a marine ecologist at the Smithsonian Tropical Research Institute (STRI) in Panama, talks about how he studies the parasites of invasive marine animals such as snails. Much of his research focuses on biological invasions and the dynamics between the host, the parasites and the surrounding ecosystem.

The post Meet our Scientist–Mark Torchin tracks invasive marine species and their parasites in Panama appeared first on Smithsonian Insider.

A robotic male frog attracts a female tungara frog in a sound chamber at the Smithsonian Tropical Research Institute, Gamboa, Panama, in the summer 2013. […]

The post Robofrog fools female tungara frog appeared first on Smithsonian Insider.

 This film depicts the Onward Brass Band parading through the French Quarter of New Orleans and picking up second liners along the way. The […]

The post New Orleans Jazz Parade – 1968 appeared first on Smithsonian Insider.

“Parallax Gap” transforms the Renwick Gallery’s Bettie Rubenstein Grand Salon into a visual puzzle. This immersive, site-specific installation explores examples of interplay between craft and […]

The post About the Renwick’s “Parallax Gap” appeared first on Smithsonian Insider.

Zebra mussels in the Great Lakes, lionfish in the Atlantic and pythons in the Everglades: Large creatures like these generally draw the spotlight when talking […]

The post DNA is trusty new weapon for detecting slime nets and other invasive marine parasites appeared first on Smithsonian Insider.

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 […]

The post Study shows parasites may be among earliest victims of climate change appeared first on Smithsonian Insider.

The new copper(II) complex [CuLCl2]2, where L is a product of Schiff base condensation between methyl­amine and 2-pyridine­carbaldehyde, is built of discrete centrosymmetric dimers.

The new copper(II) complex, namely, di-μ-chlorido-bis{chlorido[methyl(pyridin-2-ylmethylidene)amine-κ2N,N']copper(II)}, [Cu2Cl4(C7H8N2)2], (I), with the ligand 2-pyridylmethyl-N-methylimine (L, a product of Schiff base condensation between methylamine and 2-pyridinecarbaldehyde) is built of discrete centrosymmetric dimers. The coordination about the CuII ion can be described as distorted square pyramidal. The base of the pyramid consists of two nitrogen atoms from the bidentate chelate L [Cu—N = 2.0241 (9), 2.0374 (8) Å] and two chlorine atoms [Cu—Cl = 2.2500 (3), 2.2835 (3) Å]. The apical position is occupied by another Cl atom with the apical bond being significantly elongated at 2.6112 (3) Å. The trans angles of the base are 155.16 (3) and 173.79 (2)°. The Cu...Cu separation in the dimer is 3.4346 (3) Å. In the crystal structure, the loosely packed dimers are arranged in stacks propagating along the a axis. The X-band polycrystalline 77 K EPR spectrum of (I) demonstrates a typical axial pattern characteristic of mononuclear CuII complexes. Compound (I) is redox active and shows a cyclic voltammetric response with E1/2 = −0.037 V versus silver–silver chloride electrode (SSCE) assignable to the reduction peak of CuII/CuI in methanol as solvent.

An efficient synthesis of 1-aryl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-ones, involving the diazo­tization of 3-amino-4-aryl­amino-1H-isochromen-1-ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The mol­ecules of 1-phenyl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H9N3O2, (I), are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds, while the structures of 1-(2-methyl­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C16H11N3O2, (II), and 1-(3-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the mol­ecules into simple chains, which are further linked into sheets by π-stacking inter­actions in (II) but not in (III). In the structure of 1-(4-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, (IV), isomeric with (III), a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules into sheets. When com­pound (II) was exposed to a strong acid in methanol, qu­anti­tative conversion occurred to give the ring-opened transesterification product methyl 2-[4-hy­droxy-1-(2-methyl­phen­yl)-1H-1,2,3-triazol-5-yl]benzoate, C17H15N3O3, (V), where the mol­ecules are linked by paired O—H⋯O hydrogen bonds to form centrosymmetric dimers.

An operationally simple and time-efficient approach has been developed for the synthesis of racemic N-substituted 3-(2-aryl-2-oxoeth­yl)-3-hy­droxy­indolin-2-ones by a piperidine-catalysed aldol reaction between aryl methyl ketones and N-alkyl­isatins. These aldol products were used successfully as strategic inter­mediates for the preparation of N-substituted (E)-3-(2-hetaryl-2-oxo­ethyl­idene)indolin-2-ones by a stereoselective dehydration reaction under acidic conditions. The products have all been fully characterized by 1H and 13C NMR spectroscopy, by mass spectrometry and, for a representative selection, by crystal structure analysis. In each of (RS)-1-benzyl-3-hy­droxy-3-[2-(4-meth­oxy­phen­yl)-2-oxoeth­yl]indolin-2-one, C24H21NO4, (Ic), and (RS)-1-benzyl-3-{2-[4-(di­methyl­amino)­phen­yl]-2-oxoeth­yl}-3-hy­droxy­indolin-2-one, C25H24N2O3, (Id), inversion-related pairs of mol­ecules are linked by O—H⋯O hydrogen bonds to form R22(10) rings, which are further linked into chains of rings by a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds in (Ic) and by C—H⋯π(arene) hydrogen bonds in (Id). The mol­ecules of (RS)-1-benzyl-3-hy­droxy-3-[2-oxo-2-(pyridin-4-yl)eth­yl]indolin-2-one, C22H18N2O3, (Ie), are linked into a three-dimensional framework structure by a combination of O—H⋯N, C—H⋯O and C—H⋯π(arene) hydrogen bonds. (RS)-3-[2-(Benzo[d][1,3]dioxol-5-yl)-2-oxoeth­yl]-1-benzyl-3-hy­droxy­indolin-2-one, C24H19NO5, (If), crystallizes with Z' = 2 in the space group Poverline{1} and the mol­ecules are linked into com­plex sheets by a combination of O—H⋯O, C—H⋯O and C—H⋯π(arene) hydro­gen bonds. In each of (E)-1-benzyl-3-[2-(4-fluoro­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C23H16FNO2, (IIa), and (E)-1-benzyl-3-[2-oxo-2-(thiophen-2-yl)ethylidene]indolin-2-one, C21H15NO2S, (IIg), the mol­ecules are linked into simple chains by a single C—H⋯O hydrogen bond, while those of (E)-1-benzyl-3-[2-oxo-2-(pyridin-4-yl)ethyl­idene]indolin-2-one, C22H16N2O2, (IIe), are linked by three C—H⋯O hydrogen bonds to form sheets which are further linked into a three-dimensional structure by C—H⋯π(arene) hydrogen bonds. There are no hydrogen bonds in the structures of either (E)-1-benzyl-3-[2-(4-meth­oxy­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C24H19NO3, (IIc), or (E)-1-benzyl-5-chloro-3-[2-(4-chloro­phen­yl)-2-oxo­ethyl­idene]indolin-2-one, C23H15Cl2NO2, (IIh), but the mol­ecules of (IIh) are linked into chains of π-stacked dimers by a combination of C—Cl⋯π(arene) and aromatic π–π stacking inter­actions.

File photo: LAUSD Superintendent Ramon Cortines faces a suit brought by a school district employee, who has sued him twice before.; Credit: David McNew/Getty Images

A Los Angeles Unified School District employee filed suit Wednesday accusing Superintendent Ramon Cortines of sexual harassment and retaliation, and alleging officials failed to intervene when told of the situation.

The lawsuit is the third one filed by Scot Graham, LAUSD's real estate director, who has made similar charges in previous complaints. The suit was filed in Los Angeles County Superior Court.

LAUSD General Counsel David Holmquist issued a statement Tuesday saying the courts have previously ruled on the case and the district is not aware of any new charges. "This is simply a frivolous refiling of the same allegations," he stated.

The latest suit alleges Cortines made sexual advances to Graham in 2000 soon after Cortines helped Graham get a job with the school district’s real estate leasing operations. Cortines left the school district that same year and Graham didn’t report what allegedly happened, according to the suit.

Graham claims that Cortines made additional sexual advances in 2010, the year the school board hired Cortines a second time to run the school district. The sexual advances were made at Cortines’ second home in Kern County, the suit alleges.

“Cortines’ advance shocked and disturbed Graham, who feared that declining Cortines’ request for sex would lead to unwarranted retaliatory consequences,” according to the lawsuit.

Graham said he notified his boss John Creer, and his boss’ boss James Sohn, but the school district conducted no investigation. Then in an October 2010 meeting, the suit claims General Counsel Holmquist “discouraged Graham from pursuing his claims, and suggested, in an intimidating and patronizing manner, that the incidents at the Ranch and Cortines’ unsolicited phone call were better left unreported.”

In May 2012, the district announced that it would pay $200,000 to Graham to settle his sexual harassment claims against Cortines, who by then had left the post. In the announcement, the district said Cortines denied sexually harassing Graham, but acknowledged they had a consensual relationship.

Graham later declined to sign off on the settlement. He filed one lawsuit in 2013 that was dismissed on a legal technicality and then a second one that was withdrawn in May 2014.

Five months later, the LAUSD school board rehired Cortines as an interim superintendent after the resignation of his predecessor, John Deasy. Cortines is expected to serve until a permanent replacement is chosen by the board later this year.

“What makes this different and new is the school board has rehired Ramon Cortines despite documented history of sexual harassment and sexual assault against Scot Graham,” said Rob Hennig, Graham’s lawyer.

By failing to investigate whether there was any merit to Graham’s allegations, the lawsuit argues, the school district failed in its duty to protect an employee from potential sexual harassment.

“Cortines shouldn’t have been rehired by the school board,” Hennig said.

In his statement, Holmquist said the district intends to "seek reimbursement for the taxpayers' dollars that are having to be expended in attorney's fees and costs" in dealing with Graham's allegations. The district said it spent about $240,000 defending itself against Graham's first two lawsuits.

Graham said in an interview Tuesday that he has been on leave since late last year because he’s developed a type of seizure disorder that prevents him from driving long distances.

He said he filed the latest lawsuit after the school board rehired Cortines and he was running into him in the workplace. Graham also said he felt his allegations were swept under the rug.

“No one came to talk to me…it was like being in a fraternity house,” he said.

The suit does not say how much in damages Graham is seeking, but it asks among other items for back pay, future pay, benefits, and compensation for medical treatment. It also seeks an investigation into Graham's accusations against the superintendent.

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

Aline A. Alves
Apr 15, 2020; 0:jcs.242271v1-jcs.242271
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Needle pricks not your thing? A team of National Science Foundation-funded scientists is developing wearable skin sensors that can detect what's in your sweat. They hope that one day, monitoring perspiration could bypass the need for more invasive procedures like blood draws, and provide real-time updates on health problems such as dehydration or fatigue. In a new paper, the team describes a new sensor design that can be rapidly manufactured using a "roll-to-roll" processing technique that essentially prints the sensors onto a sheet of plastic like words on a newspaper. They used the sensors to monitor the sweat rate, and the electrolytes and metabolites in sweat, from volunteers who were exercising, and others who were experiencing chemically induced perspiration. The new sensors contain a spiraling microscopic tube, or microfluidic, that wicks sweat from the skin. By tracking how fast the sweat moves through the microfluidic, the sensors can report how much a person is sweating, or their sweat rate. The microfluidics are also outfitted with chemical sensors that can detect concentrations of electrolytes like potassium and sodium, and metabolites like glucose.

Image credit: Bizen Maskey/Sunchon National University

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Many wild southern sea otters in California are infected with the parasite Toxoplasma gondii, yet the infection is fatal for only a fraction of sea otters, which has long puzzled the scientific community. A National Science Foundation-funded study identifies the parasite's specific strains that are killing southern sea otters, tracing them back to a bobcat and feral domestic cats from nearby watersheds. The study marks the first time a genetic link has been clearly established between the Toxoplasma strains in felid hosts and parasites causing fatal disease in marine wildlife. The study's results highlight how infectious agents like Toxoplasma can spread from cat feces on land to the sea, leading to detrimental impacts on marine wildlife.

Image credit: Trina Wood/UC Davis

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.

Young adults ages 18-26 should be viewed as a separate subpopulation in policy and research, because they are in a critical period of development when successes or failures could strongly affect the trajectories of their lives, says a new report from the Institute of Medicine and National Research Council.

While the U.S. Department of Veterans Affairs (VA) provides mental health care of comparable or superior quality to care provided in private and non-VA public sectors, accessibility and quality of services vary across the VA health system, leaving a substantial unmet need for mental health services among veterans of the recent wars in Afghanistan and Iraq, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.

Sexual harassment in science, engineering, and medicine diminishes the integrity of the U.S. research enterprise.

A systemwide change to the culture and climate in higher education is needed to prevent and effectively respond to sexual harassment, says a new report from the National Academies of Sciences, Engineering, and Medicine.

We urge the U.S. Department of Homeland Security to immediately stop separating migrant children from their families, based on the body of scientific evidence that underscores the potential for lifelong, harmful consequences for these children and based on human rights considerations.

The National Academies of Sciences, Engineering, and Medicine have joined with over 40 colleges, universities, and research institutions to launch an Action Collaborative on Preventing Sexual Harassment in Higher Education.