Electron microprobe analysis of 9th-12th century Islamic glass from Cordoba, Spain

Twenty-six samples from domestic assemblages of 9th–12th century Córdoba were subjected to electron microprobe analysis. The results reveal two main compositional types. The first, encountered in 13 of the samples, seems to result from the combination of plant ashes with high-impurity sand, and has some contemporary parallels from Syria and Egypt. The second type is a lead–soda–silica glass, encountered in a relatively high proportion of the glasses (11 of the 26 sampled), possibly formed by the addition of lead metal to existing glasses and with very few known parallels. These are among a very small number of results available to date on the chemical composition of glasses from medieval Spain, and the presence of a high proportion of lead–soda–silica glasses is particularly interesting, possibly indicating a technological practice unique to, or originating in, the western Muslim world

New Polymorphs of Perylene:Tetracyanoquinodimethane Charge Transfer Cocrystals

We report two hitherto unknown polymorphs of the charge transfer (CT) cocrystal perylene:tetracyanoquinodimethane (TCNQ) grown by physical vapor transport (PVT) in argon atmosphere. One of the polymorphs, named β, has stoichiometry 1:1 and adds to the three known structures with stoichiometry 1:1 (α), 2:1, and 3:1. Interestingly, below (280 ± 10) K the β structure undergoes a phase transition to what we refer to as the γ polymorph, with halving of the unit cell and reduction of symmetry from monoclinic to triclinic. Both new crystal structures present two alternating stacks with different intermolecular and intramolecular geometries. In stack S–I the perylene molecules show substantial deviations from planarity, with the angle between the naphthalene intramolecular moieties of 6.69°, and with the perylene and TCNQ molecular centroids shifted by 1.95 Å. In the second stack, S-II, the perylene is planar, and the centroids almost coincident. Structural investigations on bond length complemented by vibrational IR spectroscopy indicate that in the new polymorphs the degree of charge transfer, ρ, can be 0 or 0.12. The higher value of ionicity to be due to donor–acceptor pairs in the S-II, while molecules in S-I are closer to neutrality. Thus, the ionicity of the donor–acceptor pair depends on the stack and is comparable to that of the α polymorph which we redetermined as ρ = 0.15 ± 0.05

Multiancestry association study identifies new asthma risk loci that colocalize with immune-cell enhancer marks

We examined common variation in asthma risk by conducting a meta-analysis of worldwide asthma genome-wide association studies (23,948 asthma cases, 118,538 controls) of individuals from ethnically diverse populations. We identified five new asthma loci, found two new associations at two known asthma loci, established asthma associations at two loci previously implicated in the comorbidity of asthma plus hay fever, and confirmed nine known loci. Investigation of pleiotropy showed large overlaps in genetic variants with autoimmune and inflammatory diseases. The enrichment in enhancer marks at asthma risk loci, especially in immune cells, suggested a major role of these loci in the regulation of immunologically related mechanisms