A Cohort study evaluation of maternal PCB exposure related to time to pregnancy in daughters

Background: Polychlorinated biphenyls (PCBs) remain ubiquitous environmental contaminants. Developmental exposures are suspected to impact reproduction. Analysis of mixtures of PCBs may be problematic as components have a complex correlation structure, and along with limited sample sizes, standard regression strategies are problematic. We compared the results of a novel, empirical method to those based on categorization of PCB compounds by (1) hypothesized biological activity previously proposed and widely applied, and (2) degree of ortho- substitution (mono, di, tri), in a study of the relation of maternal serum PCBs and daughter’s time to pregnancy. Methods: We measured PCBs in maternal serum samples collected in the early postpartum in 289 daughters in the Child Health and Development Studies birth cohort. We queried time to pregnancy in these daughters 28–31 years later. We applied a novel weighted quantile sum approach to find the bad-actor compounds in the PCB mixture found in maternal serum. The approach includes empirical estimation of the weights through a bootstrap step which accounts for the variation in the estimated weights. Results: Bootstrap analyses indicated the dominant functionality groups associated with longer TTP were the dioxin-like, anti-estrogenic group (average weight, 22%) and PCBs not previously classified by biological activity (54%). In contrast, the unclassified PCBs were not important in the association with shorter TTP, where the anti-estrogenic groups and the PB-inducers group played a more important role (60% and 23%, respectively). The highly chlorinated PCBs (average weight, 89%) were mostly associated with longer TTP; in contrast, the degree of chlorination was less discriminating for shorter TTP. Finally, PCB 56 was associated with the strongest relationship with TTP with a weight of 47%. Conclusions: Our empirical approach found some associations previously identified by two classification schemes, but also identified other bad actors. This empirical method can generate hypotheses about mixture effects and mechanisms and overcomes some of the limitations of standard regression techniques

The experimental gas-phase structures of 1,3,5-trisilylbenzene and hexasilylbenzene and the theoretical structures of all benzenes with three or more silyl substituents

The structures of 1,3,5-trisilylbenzene and hexasilylbenzene in the gas phase have been determined by electron diffraction, and that of 1,3,5-trisilylbenzene by X-ray crystallography. The structures of three trisilylbenzene isomers, three tetrasilylbenzenes, pentasilylbenzene and hexasilylbenzene have been computed, ab initio and using Density Functional Theory, at levels up to MP2/6-31G*. The primary effect of silyl substituents is to narrow the ring angle at the substituted carbon atoms. Steric interactions between silyl groups on neighbouring carbon atoms lead first to displacement of these groups away from one another, and then to displacement out of the ring plane, with alternate groups moving to opposite sides of the ring. In the extreme example, hexasilylbenzene, the SiCCSi dihedral angle is 17.8(8)°

Impact of allotment on contemporary hunting conflicts| The Confederated Salish-Kootenai as example

Investigates the jurisdictional conflicts between the Confederated Salish and Kootenai tribes and the State of Montana over hunting on the Flathead Reservation

The Crystal Structure of Ethyl p-Azoxybenzoate

The low-temperature form (solid I) of the smectogenic compound ethyl p-azoxybenzoate (C18H18N2Os) is stable below 90 °C. The triclinic unit cell of space group P] and dimensions a = 7.56 + 0.02, b-- 18 35 + 0.07, c= 6.28 + 0.01 A, ¢¢= 94.38 ° + 0.30 °, ,8= 97.21 _+ 0.31 °, and y = 83.97 ° + 0.25 ° contains two molecules and has a calculated density of 1.325 g.cm-3. The observed density is 1.315 + 0.013 g.cm-3. Integrated intensities were measured at room temperature by a 20--~ scan on a four-circle diffractometer equipped with a post-diffraction monochromator and scintillation detector. The crystal structure was refined by full-matrix least-squares methods with 1460 independent reflections to a final R index of 0 093. The molecules are nearly planar (the normals to the planes of the two benzene rings diverge by only 0-5 °) and are packed in a parallel array, as contrasted with the imbricated structure which has been observed for several nematogenic crystalline solids. The carbonyl and nitroso oxygen atoms are all in the cis conformation, resulting in a large dipole component in the plane of the molecule and perpendicular to its long axis. It is speculated that this feature of the molecular structure may be characteristic of smectogenic compounds

The Crystal Structure of p-Azoxyanisole

The stable crystalline form ofp-azoxyanisole is assigned to space group P21/a (C~h) with four molecules in the unit cell having parameters a= 15-776, b= 8.112, e= 11-018 A and b\u27= 114 57 °. The crystal structure was refined by full-matrix least-squares to a final R value of 0.091 using 2507 reflections measured with a manually operated single-crystal diffractometer. The molecules are arranged in the unit cell with their long axes approximately perpendicular to the (100) plane. The angle between the normals to the two benzene rings is 22.6 °, and the -N=N- bond conformation departs from the planar trans position by approximately 4 2 °

How do gear, participation, and dealer selection decisions relate to value? A price analysis of the U.S. West Coast Sablefish

Sablefish is a commercially important species with catch allocated across multiple sectors and gear types on the U.S. West Coast. A flexibility provision in the West Coast Groundfish Trawl Catch Share Program sanctions those with trawl permits to target Sablefish with fixed gear, such as longlines or pots, allowing the total effort by gear-type to be partially determined by market forces. Sablefish prices vary depending on the characteristics of landings and had an interquartile range of $1.58 from 2011-2016. To decipher the dynamics that influence participation choices and gear-switching it is important to understand the characteristics of landings that explain variation in ex-vessel prices. Using a linear mixed model with dealer and vessel-specific random effects, this research explores the influences of gear, grade (size), condition, fishing sector, port group, landing month and year on price per round pound of Sablefish. A second linear mixed model uses weighted average price per trip that incorporates the size-composition of trip landings into the explained variable, to look for possible evidence of high-grading in sectors outside of the Catch Share program. During this presentation the results of these regressions and the role of species composition of catch in the context of the DTS trawl fishery are discussed. Preliminary results will also be shared that utilize the Economic Data Collection Program’s information from first receivers and shorebased processors to explore price as it relates to more detailed dealer characteristics

The Great Escape: A Novel Approach to Collaborative Learning (Pilot)

Healthcare continues toward team-based approaches in which multiple disciplines collaborate to ensure holistic patient care. National standards for intraprofessional collaboration guide curriculum design for entry-level occupational therapy (OT) and occupational therapy assistant (OTA) programs to ensure students acquire specific skills and knowledge needed for current OT practices. Effective intraprofessional collaboration includes effective communication, respect, trust, and understanding of role delineation, which students prefer to learn in experiential, face-to-face formats. The purpose of this study was to examine OT and OTA students’ perspectives of participating in an educational escape room (EER) as a novel experience for intraprofessional education. Investigators created an EER with a healthcare plot and conducted it at two sites with 76 students, who had 60 minutes to solve puzzles based on OT/OTA knowledge to “escape” the room. Seventy-five students provided feedback on the EER in an online survey. Participants enjoyed working together in the EER, and felt it was a fun way to apply learned skills. They reported that collaboration was a key benefit and that this learning approach made them feel like equal contributors and created a sense of accomplishment. OT educators should consider including novel game-based learning activities such as EERs in their programs and in collaboration with other programs