NACA Research Memorandums

Report presenting the reverse-thrust performance of several tail-pipe-cascade-type model thrust reversers over a range of exhaust-nozzle pressure ratios from 1.2 to 2.4. Both symmetrical and asymmetrical cascade blade shapes were investigated. Results regarding the performance of tail-pipe-cascade-type model thrust reversers having symmetrically shaped cascade blades and the performance of tail-pipe-cascade-type model thrust reversers having asymmetrically shaped cascade blades are provided

NACA Research Memorandums

Memorandum presenting an investigation of the effect of the number and width of annular flame-holder gutters on afterburner performance in a 26-inch-diameter afterburner test rig. The burner inlet temperature was held at 1250 degrees Fahrenheit. Results regarding the effect of gutter width on stability limits and effect of flame-holder blockage on pressure drop are provided

NACA Research Memorandums

Report presenting an investigation of the performance of a 20-inch-diameter ramjet engine with a high-heat-release pilot burner conducted at zero angle of attack in a free-jet test facility at a Mach number of 3.0. Two flame-holder configurations were used in conjunction with the high-heat-release pilot burner over a range of altitudes. Results regarding the performance of the high-heat-release pilot burner and performance of combustion-chamber configurations are provided

NACA Research Memorandums

Report presenting a direct-connect altitude test chamber investigation of the combustion performance of a 28-inch-diameter ramjet engine with a can-type center pilot burner. Combustion-chamber configurations with three different flame holders were investigated at a simulated flight Mach number of 2.0 and several different altitudes

Peptide-mass fingerprinting as a tool for the rapid identification and mapping of cellular proteins

For more than 25 years protein identification has largely depended on automated Edman chemistry (Hewick et al., 1981) or western blotting with an appropriate monoclonal antibody. Several limitations, however, have never been overcome. The Edman procedure is inherently slow (generally one or two peptide or protein samples per day) and does not allow direct identification of many post-translational modifications. In addition, current detection limits are in the low-picomole to upper-femtomole range (Totty et al., 1992). Protein identification by western blotting can be extremely rapid, but requires the ready availability of an extensive library of suitable antibody probes. Large-format 2D-electrophoresis systems now make it possible to resolve several thousand cellular proteins from whole-cell lysates in the low- to upper-femtomole concentration range (Patton et al., 1990), presenting significant analytical challenges. The recent introduction of matrix-assisted laser-desorption (MALD) time-of-flight mass spectrometers (Karas and Hillenkamp, 1988) has led to the rapid analysis (at high sensitivity) of peptide mixtures. New strategies have been developed using a combination of protease digestion, MALD mass spectrometry and searching of peptide-mass databases that promise rapid acceleration in the identification of proteins (Henzel et al., 1993; Pappin et al., 1993; Mann et al., 1993; James et al., 1993; Yates et al., 1993)

Health-status outcomes with invasive or conservative care in coronary disease

BACKGROUND In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline