Tetrahydrobiopterin analogues with NO-dependent pulmonary vasodilator properties

Reduced NO levels due to the deficiency of tetrahydrobiopterin (BH4) contribute to impaired vasodilation in pulmonary hypertension Due to the chemically unstable nature of BH4 it was hypothesised that oxidatively stable analogues of BR, would be able to support NO synthesis to improve Endothelial dysfunction in pulmonary hypertension Two analogues of BH4 namely 6-hydroxymethyl pterin (HMP) and 6-acetyl 7 7-dimethyl 7 8-dihydropterin (ADDP) were evaluated for vasodilator activity on precontracted rat pulmonary artery rings ADDP was administered to pulmonary hypertensive rats followed by measurement of pulmonary vascular resistance in perfused lungs and eNOS expression by immunohistochemistry ADDP and HMP caused significant relaxation in vitro in rat pulmonary arteries depleted of BH4 with a maximum relaxation at 0 3 mu M (both P<005) Vasodilator activity of ADDP and HMP was completely abolished following preincubation with the NO synthase inhibitor L-NAME ADDP and HMP did not alter relaxation induced by carbachol or spermine NONOate BH4 Itself did not produce relaxation In rats receiving ADDP 141 mg/kg/day pulmonary vasodilation induced by calcium ionophore A23187 was augmented and eNOS immunoreactivity was increased In conclusion ADDP and HMP are two analogues of BH4 which can act as oxidatively stable alternatives to BH4 in causing NO-mediated vasorelaxation Chronic treatment with ADDP resulted in Improvement of NO-mediated pulmonary artery dilation and enhanced expression of eNOS in the pulmonary vascular endothelium Chemically stable analogue, of BH4 may be able to limit endothelial dysfunction in the pulmonary vasculatur

Editor\u27s Preface, Table of Contents, and List of Attendees

These proceedings contain papers presented at the first annual Kansas State University Conference on Applied Statistics in Agriculture, held in Manhattan, Kansas, April 30 through May 2, 1989

The Space Physics Data System - Cosmic and Heliospheric Nodes

The Space Physics Data System (SPDS) is a community- driven network of information sources, linked and interfaced by World Wide Web software. The SPDS coordinators are community representatives to the NASA Space Physics Division, who are soliciting additional Web nodes, trying to keep the nodes organized, and soliciting information/suggestions about older data in danger of loss. Here we present a guide to data in Cosmic and Heliospheric nodes of the SPDS. New contributions to this system are being solicited and some funds may be available to assist with their development

Pre-phase A study for an analysis of a reusable space tug. Volume 3 - Mission and operations analysis Final report

Mission model for operational and design requirements of space tug concept

Silicon Detector Studies with an Interferometric Thickness Mapper

A laser-interferometer system has been developed to precisely map the thickness variations of large-area silicon detectors. We describe the design and operation of the apparatus and the data processing carried out to derive thickness maps. We compare the results with a map made using accelerator beams of energetic heavy ions

Trajectory generation for road vehicle obstacle avoidance using convex optimization

This paper presents a method for trajectory generation using convex optimization to find a feasible, obstacle-free path for a road vehicle. Consideration of vehicle rotation is shown to be necessary if the trajectory is to avoid obstacles specified in a fixed Earth axis system. The paper establishes that, despite the presence of significant non-linearities, it is possible to articulate the obstacle avoidance problem in a tractable convex form using multiple optimization passes. Finally, it is shown by simulation that an optimal trajectory that accounts for the vehicle’s changing velocity throughout the manoeuvre is superior to a previous analytical method that assumes constant speed

Missing salts on early Mars

Our understanding of the role of water on Mars has been profoundly influenced over the past several years by the detection of widespread aqueous alteration minerals. Clay minerals are found throughout ancient Noachian terrains and sulfate salts are abundant in younger Hesperian terrains, but these phases are rarely found together in the early Martian rock record. Full alteration assemblages are generally not recognized at local scales, hindering our ability to close mass balance in the ancient crust. Here we demonstrate the dissolution of basalt and subsequent formation of smectite results in an excess of cations that should reside with anions such as OH^−, Cl^−, SO^(2-)_3 SO^(2-)_4, SO^(2-)_4, or CO^(2-)_3 in a significant reservoir of complementary salts. Such salts are largely absent from Noachian terrains, yet the composition and/or fate of these ‘missing salts’ is critical to understanding the oxidation state and primary atmospheric volatile involved in crustal weathering on early Mars

THE EFFECT OF DESIGN AND DOSE LEVEL CHOICE ON ESTIMATlNG THE OPTIMAL DOSE IN A QUANTITATIVE DOSE-RESPONSE EXPERIMENT

D-optimality is a commonly used criterion to evaluate a design with respect to parameter estimation. The variance of the optimal dose estimate is another criterion for evaluating a design. The quantitative dose-response experiment involves fitting a model to data and estimating an optimal dose. Two techniques for estimating an optimal dose and three models are used to compare the variances of optimal dose estimates over nine equally spaced balanced designs and five fixed unequally spaced six-point designs. The results show that a design which is more D-optimal than another design does not necessarily produce optimal dose estimates with less variance

Sandstone Consolidation III Year End Report

Two areas of cap rock occurrence have been mapped, one in the upper Texas Coast and the other in South Texas. These may be related to ancient delta systems. Two high-resistivity zones have been identified in Brazoria County. The nature of the high-resistivity intervals remains enigmatic. Most of the carbonate they contain is microscopically and isotopically skeletal in origin. Few authigenic components have been identified. Isotopic data suggest minimal recycling of pore waters between shale and sandstone. Hydrolysis reactions and reactions between key pairs of minerals have been written. The goal is to plot formation waters on stability diagrams for these reaction pairs and to correlate log activity ratios with the presence or absence of cap rock and deep secondary porosity. Mineral compositions are based on microprobe data from earlier Sandstone Consolidation projects and new data collected in this project. Methods have been developed to estimate thermodynamic functions for most of these minerals at elevated temperatures. Methods differ depending on the mineral class and availability of published thermodynamic data.Bureau of Economic Geolog