Adaptive-wall wind-tunnel research at NASA-Ames Research Center

Adaptive wall wind tunnel research is summarized. Small scale two and three dimensional wind tunnel experiments and numerical experiments with a three dimensional adaptive wall simulator are included. A NACA 0012 airfoil was tested in a 25 by 13 cm slotted wall test section. Airflow through the test section walls was controlled by adjusting the pressures in segmented plenums. Interference free conditions were successfully attained in subsonic and transonic flows. For the three dimensional experiment, the 25 by 13 cm wind tunnel was modified to permit cross stream wall adjustments. The test model was a semispan wing mounted to one sidewall. Wall interference was substantially reduced at several angles of attack at Mach 0.60. A wing on wall configuration was also modeled in the numerical experiments. These flow simulations showed that free air conditions can be approximated by adjusting boundary conditions at only the floor and ceiling of the test section. No sidewall control was necessary. Typical results from these experiments are discussed

Platelet-derived growth factor Phorbol ester induces the expression of the B-chain but not of the A-chain in HEL cells

AbstractIt was shown previously [(1984) EMBO J. 3, 453-459] that after treatment of the human erythroleukemia cell line HEL with phorbol ester and dimethyl sulfoxide there was a marked increase in the amounts of megakaryotic markers, especially of platelet α-granule proteins and platelet glycoproteins. In order to investigate this differentiation process further we have studied the expression of the mRNA encoding PDGF-A and PDGF-B (c-sis). Upon addition of the phorbol ester to the culture medium the expression of the c-sis transcript was enhanced about 7-fold over a period of 4 days. With dimethyl sulfoxide there was no significant stimulation of the expression. Addition of cycloheximide to HEL cells treated for a short period with phorbol ester superinduced the expression of the c-sis gene. The HEL cells did not express the A-chain mRNA even in the presence of phorbol ester or dimethyl sulfoxide. This leads us to propose that synthesis of the PDGF-A chain and PDGF-B chain is differentially regulated in the megakaryocytic-like HEL cell line

Topological and functional aspects of the proton conductor, F0_0, of the Escherichia coli ATP-synthase

The isolated H$^+$ conductor, F$_0$ , of the Escherichia co1i ATP-synthase consists of three subunits, a, b, and c. H$^+$ -permeable liposomes can be reconstit~ted with F$_0$ and lipids; addition of F$_1$-ATPase reconstitutes a functional ATP-synthase. Mutants with altered or misslng F$_0$ subunits are defective in H$^+$ conduction. Thus, all three subunits are necessary for the expression of H$^+$ conduction. The subunits a and b contain binding sites for F$_1$• Computer calculations, cross-links, membrane-permeating photo-reactive labels, and proteases were used to develop tentative structural models for the individual F$_0$ subunits

I Want to be the Inquiry Guy! How Research Experiences for Teachers Change Beliefs, Attitudes, and Values About Teaching Science as Inquiry

This qualitative study examined how and why research experiences for teachers (RETs) influenced middle and high school science teachers’ beliefs, attitudes, and values about teaching science as inquiry. Changes teachers reported after participating in the RET ranged from modifying a few lessons (belief change) to a comprehensive revision of what and how they taught to better reflect inquiry (attitude change). Some teachers who described comprehensively changing their instruction also described implementing actions meant to change science education within their respective schools, not just their own classrooms (value change). We present how and why teachers went about changes in their practices in relation to the researcher-created teacher inquiry beliefs system spectrum (TIBSS). The TIBSS conceptualizes the range of changes observed in participating teachers. We also describe the features of the RET and external factors, such as personal experiences and school contexts, that teachers cited as influential to these changes

Wind Tunnel Measurements of the Wake of a Full-Scale UH-60A Rotor in Forward Flight

A full-scale UH-60A rotor was tested in the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel in May 2010. The test was designed to acquire a suite of measurements to validate state-of-the-art modeling tools. Measurements include blade airloads (from a single pressure-instrumented blade), blade structural loads (strain gages), rotor performance (rotor balance and torque measurements), blade deformation (stereo-photogrammetry), and rotor wake measurements (Particle Image Velocimetry (PIV) and Retro-reflective Backward Oriented Schlieren (RBOS)). During the test, PIV measurements of flow field velocities were acquired in a stationary cross-flow plane located on the advancing side of the rotor disk at approximately 90 deg rotor azimuth. At each test condition, blade position relative to the measurement plane was varied. The region of interest (ROI) was 4-ft high by 14-ft wide and covered the outer half of the blade radius. Although PIV measurements were acquired in only one plane, much information can be gleaned by studying the rotor wake trajectory in this plane, especially when such measurements are augmented by blade airloads and RBOS data. This paper will provide a comparison between PIV and RBOS measurements of tip vortex position and vortex filament orientation for multiple rotor test conditions. Blade displacement measurements over the complete rotor disk will also be presented documenting blade-to-blade differences in tip-path-plane and providing additional information for correlation with PIV and RBOS measurements of tip vortex location. In addition, PIV measurements of tip vortex core diameter and strength will be presented. Vortex strength will be compared with measurements of maximum bound circulation on the rotor blade determined from pressure distributions obtained from 235 pressure sensors distributed over 9 radial stations

Antimicrobial and anti-inflammatory activity of chitosan-alginate nanoparticles: a targeted therapy for cutaneous pathogens.

Advances in nanotechnology have demonstrated potential application of nanoparticles (NPs) for effective and targeted drug delivery. Here we investigated the antimicrobial and immunological properties and the feasibility of using NPs to deliver antimicrobial agents to treat a cutaneous pathogen. NPs synthesized with chitosan and alginate demonstrated a direct antimicrobial activity in vitro against Propionibacterium acnes, the bacterium linked to the pathogenesis of acne. By electron microscopy (EM) imaging, chitosan-alginate NPs were found to induce the disruption of the P. acnes cell membrane, providing a mechanism for the bactericidal effect. The chitosan-alginate NPs also exhibited anti-inflammatory properties as they inhibited P. acnes-induced inflammatory cytokine production in human monocytes and keratinocytes. Furthermore, benzoyl peroxide (BP), a commonly used antiacne drug, was effectively encapsulated in the chitosan-alginate NPs and demonstrated superior antimicrobial activity against P. acnes compared with BP alone while demonstrating less toxicity to eukaryotic cells. Together, these data suggest the potential utility of topical delivery of chitosan-alginate NP-encapsulated drug therapy for the treatment of dermatologic conditions with infectious and inflammatory components

Model Deformation Measurements of Sonic Boom Models in the NASA Ames 9- by 7-Ft Supersonic Wind Tunnel

The deformations of two sonic-boom models were measured by stereo photogrammetry during tests in the 9- by 7-Ft Supersonic Wind Tunnel at NASA Ames Research Center. The models were geometrically similar but one was 2.75 times as large as the other. Deformation measurements were made by simultaneously imaging the upper surfaces of the models from two directions by calibrated cameras that were mounted behind windows of the test section. Bending and twist were measured at discrete points using conventional circular targets that had been marked along the leading and trailing edges of the wings and tails. In addition, continuous distributions of bending and twist were measured from ink speckles that had been applied to the upper surfaces of the model. Measurements were made at wind-on (M = 1.6) and wind-off conditions over a range of angles of attack between 2.5 deg. and 5.0 deg. At each condition, model deformation was determined by comparing the wind-off and wind-on coordinates of each measurement point after transforming the coordinates to reference coordinates tied to the model. The necessary transformations were determined by measuring the positions of a set of targets on the rigid center-body of the models whose model-axes coordinates were known. Smoothly varying bending and twist measurements were obtained at all conditions. Bending displacements increased in proportion to the square of the distance to the centerline. Maximum deflection of the wingtip of the larger model was about 5 mm (2% of the semispan) and that of the smaller model was 0.9 mm (1% of the semispan). The change in wing twist due to bending increased in direct proportion to distance from the centerline and reached a (absolute) maximum of about -1 at the highest angle of attack for both models. The measurements easily resolved bending displacements as small as 0.05 mm and bending-induced changes in twist as small as 0.05 deg

Revision Total Shoulder Arthroplasty is Associated with Increased Thirty-Day Postoperative Complications and Wound Infections Relative to Primary Total Shoulder Arthroplasty

© 2017, Hospital for Special Surgery. Background: With an increasing volume of primary total shoulder arthroplasties (TSA), the number of revision TSA cases is expected to increase as well. However, the postoperative medical morbidity of revision TSA has not been clearly described. Questions/Purposes: The purpose of this study was to determine the rate of postoperative complications following revision TSA, relative to primary TSA. In addition, we sought to identify independent predictors of complications, as well as to compare operative time and postoperative length of stay between primary and revision TSA. Methods: Patients who underwent primary/revision TSA between 2005 and 2015 were identified in the American College of Surgeons National Surgical Quality Improvement Program. Differences in complications, readmission rates, operative time, length of stay, and predictors of complications were evaluated using bivariate and multivariate analyses. Results: A total of 10,371 primary TSA (95.4%) and 496 revision TSA cases (4.6%) were identified. The overall complication rate was 6.5% in primary and 10.7% in revision TSA patients (p \u3c 0.001). Multivariate analysis identified an increased risk of any complication (odds ratio 1.73, p \u3c 0.001), major complication (2.08, p = 0.001), and wound infection (3.45, p = 0.001) in revision TSA patients, relative to primary cases. Operative time was increased in revision cases (mean ± standard deviation, 125 ± 62.5), relative to primary (115 ± 47.7, p \u3c 0.001). Age \u3e 75, female sex, history of diabetes or chronic obstructive pulmonary disease, and American Society of Anesthesiologists classification ≥ 3 were associated with increased risk of any complication. Smoking history was the only significant predictor of wound infection. Conclusion: Revision TSA, in comparison to primary, poses an increased risk of postoperative complications, particularly wound infections. A history of smoking was an independent predictor of wound infections