Persistence and Eventual Demise of Oxygen Molecules at Terapascal Pressures

Computational searches for structures of solid oxygen under high pressures in the multi-TPa range are carried out using density-functional-theory methods. We find that molecular oxygen persists to about 1.9 TPa at which it transforms into a semiconducting square-spiral-like polymeric structure (I41/acd) with a band gap of ∼3.0  eV. Solid oxygen forms a metallic zigzag chainlike structure (Cmcm) at about 3.0 TPa, but the chains in each layer gradually merge as the pressure is increased and a structure of Fmmm symmetry forms at about 9.3 TPa in which each atom has four nearest neighbors. The superconducting properties of molecular oxygen do not vary much with compression, although the structure becomes more symmetric. The electronic properties of oxygen have a complex evolution with pressure, swapping between insulating, semiconducting, and metallic

Hypoglycaemic and Antioxidant Effects of Propolis of Chihuahua in a Model of Experimental Diabetes

Propolis is a bee-collected natural product that has been proven to have various bioactivities. This study tested the effects of a Mexican propolis on streptozotocin-induced diabetes mellitus in a murine model. The results showed that an ethanolic extract of propolis of Chihuahua (EEPCh) significantly inhibited increases in blood glucose and the loss of body weight in diabetic mice. EEPCh increased plasma insulin levels in STZ-diabetic mice, whereas, in untreated diabetic mice, there was no detection of insulin. EEPCh had a high antioxidant capacity (SA50 = 15.75 μg/mL), which was directly related to the concentrations of total phenols (314 mg GAE/g of extract) and flavonoids (6.25 mg QE/g of extract). In addition, increased activities of the enzymes superoxide dismutase, catalase, and glutathione peroxidase were observed in diabetic mice treated with EEPCh. Compounds such as pinocembrin, quercetin, naringin, naringenin, kaempferol, acacetin, luteolin, and chrysin were identified by HPLC-MS analysis. This investigation demonstrated that propolis of Chihuahua possesses hypoglycaemic and antioxidant activities and can alleviate symptoms of diabetes mellitus in mice. These effects may be directly related to the chemical composition of propolis, as most of the compounds identified in propolis are reportedly active in terms of the different parameters evaluated in this work

Decomposition and Terapascal Phases of Water Ice

Computational searches for stable and metastable structures of water ice and other H:O compositions at TPa pressures have led us to predict that H2O decomposes into H2O2 and a hydrogen-rich phase at pressures of a little over 5 TPa. The hydrogen-rich phase is stable over a wide range of hydrogen contents, and it might play a role in the erosion of the icy component of the cores of gas giants as H2O comes into contact with hydrogen. Metallization of H2O is predicted at a higher pressure of just over 6 TPa, and therefore H2O does not have a thermodynamically stable low-temperature metallic form. We have also found a new and rich mineralogy of complicated water ice phases that are more stable in the pressure range 0.8–2 TPa than any predicted previously

Stable all-nitrogen metallic salt at terapascal Pressures

The phase diagram and equation of state of dense nitrogen are of interest in understanding the fundamental physics and chemistry under extreme conditions, including planetary processes, and in discovering new materials. We predict several stable phases of nitrogen at multi-TPa pressures, including a P4/nbm structure consisting of partially charged N2δ+ pairs and N5δ- tetrahedra, which is stable in the range 2.5–6.8 TPa. This is followed by a modulated layered structure between 6.8 and 12.6 TPa, which also exhibits a significant charge transfer. The P4/nbm metallic nitrogen salt and the modulated structure are stable at high pressures and temperatures, and they exhibit strongly ionic features and charge density distortions, which is unexpected in an element under such extreme conditions and could represent a new class of nitrogen materials. The P-T phase diagram of nitrogen at TPa pressures is investigated using quasiharmonic phonon calculations and ab initio molecular dynamics simulations

Postaragonite phases of CaCO3 at lower mantle pressures

The stability, structure and properties of carbonate minerals at lower mantle conditions has significant impact on our understanding of the global carbon cycle and the composition of the interior of the Earth. In recent years, there has been significant interest in the behavior of carbonates at lower mantle conditions, specifically in their carbon hybridization, which has relevance for the storage of carbon within the deep mantle. Using high-pressure synchrotron X-ray diffraction in a diamond anvil cell coupled with direct laser heating of CaCO3 using a CO2 laser, we identify a crystalline phase of the material above 40 GPa − corresponding to a lower mantle depth of around 1,000 km − which has first been predicted by ab initio structure predictions. The observed sp2 carbon hybridized species at 40 GPa is monoclinic with P21/c symmetry and is stable up to 50 GPa, above which it transforms into a structure which cannot be indexed by existing known phases. A combination of ab initio random structure search (AIRSS) and quasi-harmonic approximation (QHA) calculations are used to re-explore the relative phase stabilities of the rich phase diagram of CaCO3. Nudged elastic band (NEB) calculations are used to investigate the reaction mechanisms between relevant crystal phases of CaCO3 and we postulate that the mineral is capable of undergoing sp2-sp3 hybridization change purely in the P21/c structure − forgoing the accepted post-aragonite Pmmn structure

Antimicrobial activity of Bursera morelensis ramírez essential oil

Background: Bursera morelensis, known as “Aceitillo”, is an endemic tree of Mexico. Infusions made from the bark of this species have been used for the treatment of skin infections and for their wound healing properties. In this work, we present the results of a phytochemical and antimicrobial investigation of the essential oil of B. morelensis.Materials and Methods: The essential oil was obtained by a steam distillation method and analyzed using GC-MS. The antibacterial and antifungal activities were evaluated.Results: GC-MS of the essential oil demonstrated the presence of 28 compounds. The principal compound of the essential oil was α-Phellandrene (32.69%). The essential oil had antibacterial activity against Gram positive and negative strains. The most sensitive strains were S. pneumoniae, V. cholerae (cc) and E. coli (MIC 0.125 mg/mL, MBC 0.25 mg/mL). The essential oil was bactericidal for V. cholera (cc). The essential oil inhibited all the filamentous fungi. F. monilifome (IC50 = 2.27 mg/mL) was the most sensitive fungal strain.Conclusions: This work provides evidence that confirms the antimicrobial activity of the B. morelensis essential oil and this is a scientific support about of traditional uses of this species.Keywords: Essential oil; Medicinal plants; Tehuacan-Cuicatlan Valley; Burseraceae; Burser

Comparative Analysis of Primary and Secondary Metabolites in the Peel of Eight Blood Orange Varieties

The global cultivation of blood oranges is experiencing an increase due to their remarkable nutritional properties. Blood orange by-products, especially the peel, have a high concentration of bioactive compounds with exceptional antioxidant potential, making them an ideal choice for incorporation into various food products. This study aimed to determine the morphological parameters and primary and secondary metabolite content of peel of eight blood orange varieties using 1H NMR and HPLC-ESI-DAD-MSn. “Tarocco Meli” had the highest weight (367.83 g), caliber (94.13 mm and 88.87 mm), peel thickness (6.73 mm), and peel weight (155.0 g). “Tarocco Rosso”, “Sanguinelli”, and “Tarocco Gallo” had the highest levels of total amino acids (25.57 g kg−1 DW), total organic acids (29.99 g kg−1 DW), and total sugars (68.56 g 100 g−1 DW), respectively. The peel of “Moro” had significantly higher concentrations of total anthocyanins, hydroxycinnamic acids, and flavones (650.67, 263.33, and 449.85 mg kg−1, respectively) compared to the other varieties. In conclusion, “Tarocco Meli” had the most interesting values for morphological parameters, “Tarocco Rosso”, “Sanguinelli”, and “Tarocco Gallo” for primary metabolites, and “Moro” for secondary metabolites. With the increasing interest in utilizing co-products, these findings could be useful in developing functional food products that meet consumer demands for healthier and more sustainable food choice

Gravity and seismic study of crustal structure along the Juan de Fuca Ridge axis and across pseudofaults on the ridge flanks

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 12 (2011): Q05008, doi:10.1029/2010GC003439.Variations in topography and seismic structure are observed along the Juan de Fuca (JdF) Ridge axis and in the vicinity of pseudofaults on the ridge flanks left by former episodes of ridge propagation. Here we analyze gravity data coregistered with multichannel seismic data from the JdF Ridge and flanks in order to better understand the origin of crustal structure variations in this area. The data were collected along the ridge axis and along three ridge-perpendicular transects at the Endeavor, Northern Symmetric, and Cleft segments. Negative Mantle Bouguer anomalies of −21 to −28 mGal are observed at the axis of the three segments. Thicker crust at the Endeavor and Cleft segments is inferred from seismic data and can account for the small differences in axial gravity anomalies (3–7 mGal). Additional low densities/elevated temperatures within and/or below the axial crust are required to explain the remaining axial MBA low at all segments. Gravity models indicate that the region of low densities is wider beneath the Cleft segment. Gravity models for pseudofaults crossed along the three transects support the presence of thinner and denser crust within the pseudofault zones that we attribute to iron-enriched crust. On the young crust side of the pseudofaults, a 10–20 km wide zone of thicker crust is found. Reflection events interpreted as subcrustal sills underlie the zones of thicker crust and are the presumed source for the iron enrichment.This work was supported by the National Science Foundation grants OCE‐0648303 to Lamont‐Doherty Earth Observatory, OCE‐0648923 to Woods Hole Oceanographic Institution

Design and development of a multiplex microsatellite panel for the genetic characterisation and diversity assessment of domestic turkey (Meleagris gallopavo gallopavo)

Domestic turkey production generally utilises only a few genetically improved lines, and local breeds are severely endangered as a result. Furthermore, the genetic resources of domestic turkeys have not been properly investigated, which could, ultimately, lead to the extinction of local breeds and negatively affect their corresponding genetic diversity and environmental adaptation. Although, several microsatellite markers have been designed for mapping and quantitative trait locus analysis, there is no standard panel of markers for genetic characterisation or genetic diversity assessment. Accordingly, the present study aimed to develop a set of polymorphic microsatellite markers that could be used for international turkey population studies. Thirty-nine microsatellites were selected based on polymorphism, DNA sequence and chromosome position, as well as on amplification efficiency, success rate and the absence of nonspecific amplification. The markers were screened using 105 DNA samples from local turkey breeds from Mexico, the United States, Italy, Brazil, Egypt and Spain. A total of 401 alleles were identified, with a mean number of alleles per marker of 10.28 \ub1 4.25. All microsatellites were polymorphic, with at least four alleles and no more than 19 alleles. Furthermore, allelic richness ranged from 3.810 to 17.985, mean heterozygosity ranged from 0.452 \ub1 0.229 to 0.667 \ub1 0.265, polymorphic information content values ranged from 0.213 (MNT264) to 0.850 (RHT0024) and the mean Fis value was 0.322. Overall, the panel was highly polymorphic and exhibited moderate Hardy\u2013Weinberg disequilibrium, thereby indicating its value as a tool for biodiversity and population structure studies that could play an important role in promoting the conservation of local turkey breeds.Highlights Important genetic resources reside within indigenous turkey populations. These are linked to historic heritage production values and breeds. It is important to preserve this heritage and genetic diversity, which threatens to be lost as production systems focus on production characteristics. Microsatellite markers, even though, they are now replaced by single nucleotide polymorphism automatic genotyping platforms in many fields of genetics, remain a viable alternative thanks to their cheapness and simplicity of study which makes them particularly useful when the population to be studied lacks information of the prior genetic structure