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 fossil teeth of a 15- to 18-million-year-old three-toed browsing horse, Anchitherium clarencei, were recently discovered by scientists from the Smithsonian Tropical Research Institute and the […]

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The whole-genome analysis of two Tasmanian devils—one that died of a new contagious cancer known as Devil Facial Tumor Disease (DFTD) and one healthy animal—is at the center of a new management strategy to help prevent the extinction of this species.

The post Whole-genome analysis at center of effort to save Tasmanian devil 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.

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 […]

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The discovery of two new extinct camel species by scientists from the University of Florida and the Smithsonian is casting new light on the history of the tropics, a region containing more than half the world's biodiversity and some of its most important ecosystems.

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Douglas Owsley, the division head for physical anthropology at the Smithsonian’s National Museum of Natural History, presented today a forensic analysis of 17th-century human remains […]

The post Forensic analysis of 17th-century human remains at Jamestown, Va., reveals evidence of survival cannibalism appeared first on Smithsonian Insider.

A research team from the Smithsonian and Arizona State University have developed a new, non-destructive method using spectroscopic analysis to help unravel the complex chemistry […]

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Studies show that on average, the weight of cremated remains for men is about 7.13 pounds (plus or minus 1.2 pounds) and for women, 4.9 […]

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Seven fossil teeth exposed by the Panama Canal expansion project are the first evidence of a monkey on the North American continent before the Isthmus […]

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Death-associated protein kinase 1 (DAPK1) is a serine/threonine protein kinase that regulates apoptosis and autophagy. DAPK1 is considered to be a therapeutic target for amyloid-β deposition, endometrial adenocarcinomas and acute ischemic stroke. Here, the potent inhibitory activity of the natural anthraquinone purpurin against DAPK1 phosphorylation is shown. Thermodynamic analysis revealed that while the binding affinity of purpurin is similar to that of CPR005231, which is a DAPK1 inhibitor with an imidazopyridazine moiety, the binding of purpurin was more enthalpically favorable. In addition, the inhibition potencies were correlated with the enthalpic changes but not with the binding affinities. Crystallographic analysis of the DAPK1–purpurin complex revealed that the formation of a hydrogen-bond network is likely to contribute to the favorable enthalpic changes and that stabilization of the glycine-rich loop may cause less favorable entropic changes. The present findings indicate that purpurin may be a good lead compound for the discovery of inhibitors of DAPK1, and the observation of enthalpic changes could provide important clues for drug development.

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.

Miniature camels and horses, a rhinoceros and a giant bear-dog are among fossils unearthed in the recent excavations of the Panama Canal expansion project. These […]

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A global analysis raises the minimum estimated number of tropical tree species to at least 40,000–53,000 worldwide in a paper appearing in Proceedings of the […]

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The Smithsonian Tropical Research Institute (STRI) celebrated with Panama the completion of the Panama Canal expansion project on June 26, 2016. The $5.6 billion engineering […]

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In the structure of the title salt, second-order Jahn–Teller distortion of the coordination octa­hedra around V ions is reflected by coexistence of short V—O bonds and trans-positioned long V—F bonds, with four equatorial V—F distances being inter­mediate in magnitude. Hydrogen bonding of the anions is restricted to F-atom acceptors only, with particularly strong N–H⋯F inter­actions [N⋯F = 2.5072 (15) Å] established by axial and cis-positioned equatorial F atoms.

The asymmetric unit of the title compound contains two independent mol­ecules, consisting of perimidine and phenol units, which are linked through an N—H⋯O hydrogen bond. Intra­molecular O—H⋯N hydrogen bonds are observed in both independent mol­ecules.

The title compound, 1-(2,5-di­meth­oxy­phen­yl)-2,2,6,6-tetra­methyl­piperidine, was synthesized as a side-product during the synthesis of the inter­mediate, methyl 3,6-dimeth­oxy-2-(2-meth­oxy-2-oxoeth­yl)benzoate, necessary for the total synthesis of the isocoumarin 5,8-dimeth­oxy-3-methyl-1H-isochromen-1-one.

The title compound exhibits exceptionally weak inter­molecular C—H⋯π hydrogen bonding of the ethynyl groups, with the corresponding H⋯π separations [2.91 (2) and 3.12 (2) Å] exceeding normal vdW distances. This bonding compliments distal contacts of the CH (aliphatic)⋯π type [H⋯π = 3.12 (2)–3.14 (2) Å] to sustain supra­molecular layers.

The dihedral angle between the two aromatic rings of the title compound is 64.12 (14)°. The crystal structure is stabilized by a short Cl⋯H contact, C—Cl⋯π and van der Waals inter­actions.

The title complex, Cu(L)2 or [Cu(C15HF10O2)2], comprising one copper ion and two fully fluorinated ligands (L−), was crystallized with 3,4-ethyl­ene­dioxy­thio­phene (EDOT, C6H6O2S) as a guest mol­ecule to give in a di­chloro­methane solution a unique co-crystal, Cu(L)2·3C6H6O2S.

The structural and nonlinear optical properties of a new anilinium hybrid crystal of chemical formula (C6H7NCl+·NO3−)3 have been investigated. The crystal structure was determined from single-crystal X-ray diffraction measurements performed at a temperature of 100 K which show that the compound crystallizes in a noncentrosymmetric space group (Pna21). The structural analysis was coupled with Hirshfeld surface analysis to evaluate the contribution of the different intermolecular interactions to the formation of supramolecular assemblies in the solid state that exhibit nonlinear optical features. This analysis reveals that the studied compound is characterized by a three-dimensional network of hydrogen bonds and the main contributions are provided by the O...H, C...H, H...H and Cl...H interactions, which alone represent ∼85% of the total contributions to the Hirshfeld surfaces. It is noteworthy that the halogen...H contributions are quite comparable with those of the H...H contacts. The nonlinear optical properties were investigated by nonlinear diffuse femtosecond-pulse reflectometry and the obtained results were compared with those of the reference material LiNbO3. The hybrid crystals exhibit notable second (SHG) and third (THG) harmonic generation which confirms its polarity is generated by the different intermolecular interactions. These measurements also highlight that the THG signal of the new anilinium compound normalized to its SHG counterpart is more pronounced than for LiNbO3.

In the title compound, C16H14Cl2FN3, the dihedral angle between the two aromatic rings is 64.12 (14)°. The crystal structure is stabilized by a short Cl...H contact, C—Cl...π and van der Waals interactions. The Hirshfeld surface analysis and two-dimensional fingerprint plots show that H...H (33.3%), Cl...H/H...Cl (22.9%) and C...H/H...C (15.5%) interactions are the most important contributors towards the crystal packing.

The title compound, C14H16, exhibits exceptionally weak intermolecular C—H...π hydrogen bonding of the ethynyl groups, with the corresponding H...π separations [2.91 (2) and 3.12 (2) Å] exceeding normal vdW distances. This bonding complements distal contacts of the CH (aliphatic)...π type [H...π = 3.12 (2)–3.14 (2) Å] to sustain supramolecular layers. Hirshfeld surface analysis of the title compound suggests a relatively limited significance of the C...H/H...C contacts to the crystal packing (24.6%) and a major contribution from H...H contacts accounting 74.9% to the entire surface.

The asymmetric unit of the title compound, C17H14N2O, contains two independent molecules each consisting of perimidine and phenol units. The tricyclic perimidine units contain naphthalene ring systems and non-planar C4N2 rings adopting envelope conformations with the C atoms of the NCN groups hinged by 44.11 (7) and 48.50 (6)° with respect to the best planes of the other five atoms. Intramolecular O—H...N hydrogen bonds may help to consolidate the molecular conformations. The two independent molecules are linked through an N—H...O hydrogen bond. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (52.9%) and H...C/C...H (39.5%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 G(d,p) level are compared with the experimentally determined molecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.

In the title compound, C17H27NO2, the piperidine ring has a chair conformation and is positioned normal to the benzene ring. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming chains propagating along the c-axis direction.

In the structure of the title salt, (C7H12N6)[VOF5], second-order Jahn–Teller distortion of the coordination octahedra around V ions is reflected by coexistence of short V—O bonds [1.5767 (12) Å] and trans-positioned long V—F bonds [2.0981 (9) Å], with four equatorial V—F distances being intermediate in magnitude [1.7977 (9)–1.8913 (9) Å]. Hydrogen bonding of the anions is restricted to F-atom acceptors only, with particularly strong N–H...F interactions [N...F = 2.5072 (15) Å] established by axial and cis-positioned equatorial F atoms. Hirshfeld surface analysis indicates that the most important interactions are overwhelmingly H...F/F...H, accounting for 74.4 and 36.8% of the contacts for the individual anions and cations, respectively. Weak CH...F and CH...N bonds are essential for generation of three-dimensional structure.

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 analytical solution of the problem of X-ray spherical-wave Laue diffraction in a single crystal with a linear change of thickness on the exit surface is derived. General equations are applied to a specific case of plane-wave Laue diffraction in a thick crystal under the conditions of the Borrmann effect.

Using mineralogical data, it is demonstrated that chemical simplicity measured as an amount of Shannon information per atom on average corresponds to higher symmetry measured as an order of the point group of a mineral, which provides a modern formulation of the Fedorov–Groth law.

The analysis used by federal agencies to set standards for fuel economy and greenhouse gas emissions for new U.S. light-duty vehicles -- passenger cars and light trucks -- from 2017 to 2025 was thorough and of high caliber overall, says a new report from the National Research Council.

To ensure the Comprehensive Everglades Restoration Plan (CERP) is responsive to changing environmental conditions like climate change and sea-level rise, as well as to changes in water management, a new report by the National Academies of Sciences, Engineering, and Medicine calls for a re-examination of the program’s original restoration goals and recommends a forward-looking, systemwide analysis of Everglades restoration outcomes across a range of scenarios.

NASA’s investment in new instruments to analyze extraterrestrial samples is insufficient to provide for replacement of existing instruments, says a new report from the National Academies of Sciences, Engineering, and Medicine.

The global production, trade and use of goods and services has a significant impact on the environment — and rates of consumption are rising. A new study combines two assessment methods to quantify the impact of European trade on the environment. It finds that, overall, the EU was a net importer of environmental impact from 2000 to 2010, that machinery, equipment and vehicles contributed most to the EU’s export impacts and that the EU’s trade balance (import impact minus export impact) is increasing over time. The two assessment methods complement one another well and could form the basis for future country or region-wide studies, suggest the researchers, by enabling a detailed analysis of individual steps within a product’s trade flow, while also providing a larger picture of the overall process.

New research from Sweden identifies the characteristics of substance flow analyses that make them useful to policy makers. Substance flow analyses that focus on measuring rather than modelling pollution and which are aligned to existing measures are more likely to influence policy.

Researchers have created a new Green Option Matrix (GOM) to describe and compare the ever growing number of options to develop green products and processes. The GOM was used to analyse 142 companies belonging to the Dow Jones Sustainability World Index.

Using archival documents, a new report published online by JAMA Internal Medicine examines the sugar industry's role in coronary heart disease research and suggests the industry sponsored research to influence the scientific debate to cast doubt on the hazards of sugar and to promote dietary fat as the culprit in heart disease.

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Risk analysis and technology assessment (RATA) involves assessing the possible human, environmental and societal risks of a novel technology at various stages of the development process. However, best practices for RATA’s successful incorporation into large-scale research programmes are still in development. In a recent study, researchers present a case study of their efforts to bring RATA into practice within a large Dutch nanotechnology consortium. By outlining the procedures and products they developed and reflecting on their experiences, the researchers provide valuable insights for the future integration of RATA in technology development projects. The findings are relevant to stakeholders with an interest in supporting the design of key enabling technologies, including governmental agencies and industrial partners.

New research identifies important influences on the energy and environmental performance of biofuels made from agricultural crops. Type of land use change, type of biofuel crop and the by-products from the conversion process all influence performance.

A study has evaluated three types of media campaign conducted by a large UK supermarket to encourage shoppers to reduce their food waste. These used social media, an e-newsletter and a print/digital magazine, respectively. Although they all appeared to lead to reductions in food waste to some extent, similar behavioural changes were also seen for customers who had not participated in any of the campaigns.

A new study provides clues as to which innovative low-carbon technologies will successfully get onto the market quickly. The historical analysis of 16 energy technologies — from steam engines to wind power — found that the average length of a product’s ‘formative phase’ is 22 years. This important period of innovation in a technology’s development is shorter for products which do not need extensive new infrastructure or changes to user behaviour. The findings could help policymakers identify new technologies that can be deployed more rapidly to meet short-term environmental targets.

A recent study highlights the role of the public sector in encouraging private investment in natural and cultural brownfield regeneration projects by analysing four models of financing: public-private partnerships, land value finance mechanisms, urban development funds and impact investment funds. Local governments, it is suggested, are well placed to identify and select the most suitable financing mechanisms for redevelopment projects.

Reluctance to use cost-benefit analysis (CBA) in environmental decision making in Germany stems from a preference for traditional approaches and a fear that it leads to loss of influence. This is suggested by new research based on interviews with those responsible for water policy management.

Improving the efficiency of industries and products has not led to overall reductions in the consumption of goods and services, a new study has found. The research looked at the historical relationship between efficiency improvements and resource consumption across 10 different activities, including electricity generation and passenger air travel. However, shorter decade-long periods, where efficiency improvements outpaced resource consumption, suggested that legislation and price pressures could be effective at reducing resource consumption.

A large proportion of ships are recycled on the beaches of developing countries in Asia. This study considered shipbreaking in Bangladesh, using critical scenario analysis to explore different futures for the industry and its workers. The paper suggests that a radical shift in socioeconomic and political structures is needed to enable environmentally sound practices while retaining employment opportunities for local people.