Extreme population inversion in the fragments formed by UV photoinduced S-H bond fission in 2-thiophenethiol

H atom loss following near ultraviolet photoexcitation of gas phase 2-thiophenethiol molecules has been studied experimentally, by photofragment translational spectroscopy (PTS) methods, and computationally, by ab initio electronic structure calculations. The long wavelength (277.5 ≥ λphot ≥ 240 nm) PTS data are consistent with S–H bond fission after population of the first 1πσ* state. The partner thiophenethiyl (R) radicals are formed predominantly in their first excited Ã2A′ state, but assignment of a weak signal attributable to H + R([X with combining tilde]2A′′) products allows determination of the S–H bond strength, D0 = 27 800 ± 100 cm−1 and the Ö[X with combining tilde] state splitting in the thiophenethiyl radical (ΔE = 3580 ± 100 cm−1). The deduced population inversion between the à and [X with combining tilde] states of the radical reflects the non-planar ground state geometry (wherein the S–H bond is directed near orthogonal to the ring plane) which, post-photoexcitation, is unable to planarise sufficiently prior to bond fission. This dictates that the dissociating molecules follow the adiabatic fragmentation pathway to electronically excited radical products. π* ← π absorption dominates at shorter excitation wavelengths. Coupling to the same 1πσ* potential energy surface (PES) remains the dominant dissociation route, but a minor yield of H atoms attributable to a rival fragmentation pathway is identified. These products are deduced to arise via unimolecular decay following internal conversion to the ground (S0) state PES via a conical intersection accessed by intra-ring C–S bond extension. The measured translational energy disposal shows a more striking change once λphot ≤ 220 nm. Once again, however, the dominant decay pathway is deduced to be S–H bond fission following coupling to the 1πσ* PES but, in this case, many of the evolving molecules are deduced to have sufficiently near-planar geometries to allow passage through the conical intersection at extended S–H bond lengths and dissociation to ground ([X with combining tilde]) state radical products. The present data provide no definitive evidence that complete ring opening can compete with fast S–H bond fission following near UV photoexcitation of 2-thiophenethiol

IODP Expeditions 309 and 312 drill an intact section of upper oceanic basement into gabbros

The Integrated Ocean Drilling Program's (IODP) Expeditions 309 and 312 successfully completed the first sampling of an intact section of upper oceanic crust, through lavas and the sheeted dikes into the uppermost gabbros. Hole 1256D, which was initiated on the Ocean Drilling Program's (ODP) Leg 206, now penetrates to >1500 mbsf and >1250 m sub-basement. The first gabbroic rocks were encountered at 1407 mbsf. Below this, the hole penetrates 3c100 m into a complex zone of fractionated gabbros intruded into contact metamorphosed dikes

Meta-analysis of type 2 Diabetes in African Americans Consortium

Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

Superfast spreading rate crust 2: a complete in situ section of upper oceanic crust formed at a superfast spreading rate.

none43sinoneJ.C. Alt; D.A.H. Teagle; S. Umino; S. Miyashita; N.R. Banerjee; D.S. Wilson; F. Einaudi; A. Belghoul; C. Cordier; L. Crispini; L. Galli; Y. Gao; J. Geldmacher; L.A. Gilbert; E. Herreo-Bervera; S.A. Holter; C. Laverne; H.L. Lledo Vasques; S. Rodriguez Durand; T. Sakuyama; T. Sano; C.E. Smith-Duque; S. Tominaga; P. Tartarotti; E.A. Veloso Espinosa; M. Reichow; R. Anma; J. Carlut; D.M. Christie; R. Coggon; N.W. Hayman; N. Hirano; S. Ingle; J. Koepke; J. MacLennan; S. Morgan; N. Neo; S.H. Park; B. Scheibner; S.A. Swift; A.A. Tikku; T. Yamazaki; S. YamazakiJ. C., Alt; D. A. H., Teagle; S., Umino; S., Miyashita; N. R., Banerjee; D. S., Wilson; F., Einaudi; A., Belghoul; C., Cordier; Crispini, Laura; L., Galli; Y., Gao; J., Geldmacher; L. A., Gilbert; E., Herreo Bervera; S. A., Holter; C., Laverne; H. L., Lledo Vasques; S., Rodriguez Durand; T., Sakuyama; T., Sano; C. E., Smith Duque; S., Tominaga; P., Tartarotti; E. A., Veloso Espinosa; M., Reichow; R., Anma; J., Carlut; D. M., Christie; R., Coggon; N. W., Hayman; N., Hirano; S., Ingle; J., Koepke; J., Maclennan; S., Morgan; N., Neo; S. H., Park; B., Scheibner; S. A., Swift; A. A., Tikku; T., Yamazaki; S., Yamazak