The effect of circumferential distortion on fan performance at two levels of blade loading

Single stage fans designed for two levels of pressure ratio or blade loading were subjected to screen-induced circumferential distortions of 90-degree extent. Both fan rotors were designed for a blade tip speed of 425 m/sec, blade solidity of 1.3 and a hub-to-tip radius ratio of 0.5. Circumferential measurements of total pressure, temperature, static pressure, and flow angle were obtained at the hub, mean and tip radii at five axial stations. Rotor loading level did not appear to have a significant influence on rotor response to distorted flow. Losses in overall pressure ratio due to distortion were most severe in the stator hub region of the more highly loaded stage. At the near stall operating condition tip and hub regions of (either) rotor demonstrated different response characteristics to the distorted flow. No effect of loading was apparent on interactions between rotor and upstream distorted flow fields

Development and application of a self-referencing glucose microsensor for the measurement of glucose consumption by pancreatic ?-cells

Glucose gradients generated by an artificial source and ?-cells were measured using an enzyme-based glucose microsensor, 8-?m tip diameter, as a self-referencing electrode. The technique is based on a difference measurement between two locations in a gradient and thus allows us to obtain real-time flux values with minimal impact of sensor drift or noise. Flux values were derived by incorporation of the measured differential current into Fick's first equation. In an artificial glucose gradient, a flux detection limit of 8.2 ± 0.4 pmol·cm-2·s-1 (mean ± SEM, n = 7) with a sensor sensitivity of 7.0 ± 0.4 pA/mM (mean ± SEM, n = 16) was demonstrated. Under biological conditions, the glucose sensor showed no oxygen dependence with 5 mM glucose in the bulk medium. The addition of catalase to the bulk medium was shown to ameliorate surface-dependent flux distortion close to specimens, suggesting an underlying local accumulation of hydrogen peroxide. Glucose flux from ?-cell clusters, measured in the presence of 5 mM glucose, was 61.7 ± 9.5 fmol·nL-1·s-1 (mean ± SEM, n = 9) and could be pharmacologically modulated. Glucose consumption in response to FCCP (1 ?M) transiently increased, subsequently decreasing to below basal by 93 ± 16 and 56 ± 6%, respectively (mean ± SEM, n = 5). Consumption was decreased after the application of 10 ?M rotenone by 74 ± 5% (mean ± SEM, n = 4). These results demonstrate that an enzyme-based amperometric microsensor can be applied in the self-referencing mode. Further, in obtaining glucose flux measurements from small clusters of cells, these are the first recordings of the real-time dynamic of glucose movements in a biological microenvironment. <br/

Properties of a cell line from human adenocarcinoma of the rectum.

A new, highly differentiated line of cells derived from adenocarcinoma of the rectum (HT55) is described. This line is noteworthy for the following features: 1. The role played in its development by the use of UV-inactivated Sendai virus to attach tumour cell clumps to plastic bottles. 2. Evidence that it produces RNA-containing material of density 1-5--1-16 g/ml. 3. Induction of bone formation in the stroma when grown in athymic mice. 4. Stimulation of primary CBA mouse embryo fibroblasts to form a transient nodule when mixed with them and injected into adult CBA mice. The karyotype and growth-cycle characteristics of the line are described

Certification of damage tolerant composite structure

A reliability based certification testing methodology for impact damage tolerant composite structure was developed. Cocured, adhesively bonded, and impact damaged composite static strength and fatigue life data were statistically analyzed to determine the influence of test parameters on the data scatter. The impact damage resistance and damage tolerance of various structural configurations were characterized through the analysis of an industry wide database of impact test results. Realistic impact damage certification requirements were proposed based on actual fleet aircraft data. The capabilities of available impact damage analysis methods were determined through correlation with experimental data. Probabilistic methods were developed to estimate the reliability of impact damaged composite structures

An assessment of the effects of neurokinin₁ receptor antagonism against nausea and vomiting: Relative efficacy, sites of action and lessons for future drug development.

A ‘broad-spectrum’ anti-vomiting effect of neurokinin1 receptor antagonists (NK1RA), shown in preclinical animal studies, has been supported by a more limited range of clinical studies in different indications. However, this review suggests that compared with vomiting, the self-reported sensation of nausea is less affected or possibly unaffected (depending on the stimulus) by NK1 receptor antagonism, a common finding for ‘anti-emetics’. The stimulus-independent effects of NK1RAs against vomiting are explicable by actions within the central pattern generator (CPG; ventral brainstem) and the nucleus tractus solitarius (NTS; dorsal brainstem), with additional effects on vagal afferent activity for certain stimuli (e.g., highly emetogenic chemotherapy). The CPG and NTS neurones are multifunctional so the notable lack of obvious effects of NK1RAs on other reflexes mediated by the same neurones suggests that their anti-vomiting action is dependent on the activation state of the pathway leading to vomiting. Nausea requires activation of cerebral pathways by projection of information from the NTS. Although NK1 receptors are present in cerebral nuclei implicated in nausea, and imaging studies show very high receptor occupancy at clinically used doses, the variable or limited ability of NK1RAs to inhibit nausea emphasises (a) our inadequate understanding of the mechanisms of nausea and (b) that classification of a drug as an “anti-emetic” may give a false impression of efficacy against nausea versus vomiting. We discuss the potential mechanisms for the differential efficacy of NK1RA and the implications for future development of drugs which can effectively treat nausea, an area of unmet clinical need

The Role of Hedgehog Signaling During Hemipene Development in Anolis sagrei

This project\u27s goal was to identify the role of Hedgehog signaling during hemipene development in the lizards Anolis sagrei. Hemepenes are the paired genitalia of squamates, lizards and snakes. When compared to mammals, there little known about the details of lizard genital development. Based on prior observations in mammals, we hypothesized that Sonic hedgehog (Shh) contributes to the development of hemipenes. We knocked down Hedgehog signaling during hemipene patterning to assess the function of Shh during hemipene development. Preliminary data demonstrate that Shh is critical for hemipene patterning in lizards

Design and performance of a fixed, nonaccelerating, guide vane cascade that operates over an inlet flow angle range of 60 deg

A unique set of wind tunnel guide vanes are designed with an inverse design code and analyzed with a panel method and an integral boundary layer code developed at the NASA Lewis Research Center. The fixed guide vanes, 80 feet long with 6-foot chord length, were designed for the NASA Ames 40 x 80/80 x 120 ft Wind Tunnel. Low subsonic flow is accepted over a 60 deg range of inlet angle from either the 40 x 80 leg or the 80 x 120 leg of the wind tunnel, and directed axially into the main leg of the tunnel where drive fans are located. Experimental tests of 1/10-scale models were conducted to verify design calculations

The Stability of Angiotensin I Formed at Room Temperature in the Presence of Ethylenediaminetetraacetate to Subsequent Incubation at 37 °C

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