Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation

We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10-11 to 5.0 × 10-21). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10-6). Our results provide new evidence for the role of DNA methylation in blood pressure regulation

MODELING OF CHEMICAL VAPOR DEPOSITED ZIRCONIA FOR THERMAL BARRIER AND ENVIRONMENTAL BARRIER COATINGS

Thermal and environmental barrier coatings are important components of current and future energy systems. Such coatings--applied to hot, metallic surfaces in combustors, heat exchanger and turbines--increase the allowable operating temperature and increase the efficiency of the energy system. Because of its low thermal conductivity and high thermal expansion yttria-stabilized zirconia (YSZ) is the material of choice for protection of structural components in many high temperature applications. Current coating application methods have their drawbacks, however. Air plasma spray (APS) is a relatively low-cost process and is suitable for large and relatively complex shapes. It is difficult to produce uniform, relatively thin coatings with this process, however, and the coatings do not exhibit the columnar microstructure that is needed for reliable, long-term performance. The electron-beam physical vapor deposition (EB-PVD) process does produce the desirable microstructure, however, the capital cost of these systems is very high and the line-of-sight nature of the process limits coating uniformity and the ability to coat large and complex shapes. The chemical vapor deposition (CVD) process also produces the desirable columnar microstructure and--under proper conditions--can produce uniform coatings over complex shapes. The overall goal of this project--a joint effort of the University of Louisville and Oak Ridge National Laboratory (ORNL)--is to develop the YSZ CVD process for application of thermal barrier coatings for fossil energy systems. Last year's report described our initial efforts toward developing a model for the process and for ORNL's bench-scale reactor. This model provides an understanding of the transport and kinetics phenomena that control the deposition process and ultimately will provide a tool for fullscale reactor design and optimization. Our overall research approach is: validate the 3-D computer model using experimental results at ORNL, use the model to identify and evaluate potential process improvements and design a reactor for large and complex substrates. This report describes the modeling effort at the University of Louisville which supports the experimental work at ORNL

A METHOD FOR RAPID CHEMICAL VAPOR INFILTRATION OF CERAMIC COMPOSITES

Des procédés de préparation de composites structuraux ont été développés au laboratoire national d'Oak Ridge (ORNL). Les composites sont préparés par infiltration de préformes fibreuses en céramique, à haute température, à partir de réactants gazeux qui se décomposent pour libérer la matrice céramique entre les fibres et autour. Le procédé ORNL est une nette amélioration des procédés classiques ; les temps de densification classiquement de plusieurs semaines sont réduits à quelques 24h. Des échantillons de haute densité (90 % de la densité théorique) avec des résistances de l'ordre de 400-450MPa ont été obtenus. De plus, la rupture de ces matériaux n'est pas catastrophique, montrant ainsi un réel comportement composite.Processes for the preparation of composite bodies using chemical vapor deposition have been developed at Oak Ridge National Laboratory (ORNL). Composites are prepared by infiltrating ceramic fiber preforms, held at elevated temperatures, with reactant gases that decompose to deposit ceramic matrix material between and around the fibers. The ORNL process is a marked improvement over those commonly in use ; preforms that previously required weeks to densify now require ~24 h. Specimens with densities up to 90 % of theoretical and strengths in the range of 400 to 450 MPa have been produced. Most importantly, the materials fail noncatastrophically, exhibiting typical composite behavior

Characterization of Selective Laser Sintering™ Materials to Determine Process Stability

The Selective Laser Sintering (SLS) process has proved to be an excellent method for prototyping functional parts out of engineering thermoplastics such as polyamides. However, the material undergoes physical and chemical changes due to repeated heating cycles in the SLS equipment. This causes variations in powder characteristics and performance in the SLS process. With the increased utilization of SLS for direct manufacturing it is necessary to develop a characterization and testing system that can determine powder fitness to ensure process stability and part quality. Current powder recycling methodologies use an average virgin-to-used powder mixture. In a new approach, a testing mechanism to deliver a numerical, measurable material characterization will be discussed. Experimental results of repeated reuse of material and its resulting physical effects on mechanical properties, shrinkage, and chemical tests will be presented. A definitive testing and measurement process control will be shown to improve process stability and thus part quality and consistency.Mechanical Engineerin

Effect of Powder Chemical Composition on Microstructures and Mechanical Properties of L-PBF Processed 17-4 PH Stainless Steel in the As-Built and Hardened-H900 Conditions

Post-build heat treatments such as solutionizing and precipitation hardening are recommended for selective laser melting (SLM) processed components to achieve a homogeneous microstructure. In this study, the effect of powder elemental composition on microstructures and mechanical properties of SLM processed 17-4 PH was studied in the as-built and precipitation hardened (H900) condition without prior solutionizing. Microstructural characterization demonstrated that H900 increased martensite phase composition for samples from powder with low chromium to nickel equivalent (Creq/Nieq) value, whereas no significant difference was observed for the samples from powders with high Creq/Nieq value. None of the specimens exhibited austenite reversion and strain hardening behavior in the as-built and H900 conditions. Low Creq/Nieq specimen exhibited higher yield and tensile strengths, and microhardness from H900, which are comparable to H900 wrought sample. However, no significant improvement in total elongation was observed other than uniform elongation for low Creq/Nieq specimen.Mechanical Engineerin