2,776 research outputs found

    Computational design of natural laminar flow wings for transonic transport application

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    Two research programs are described which directly relate to the application of natural laminar flow (NLF) technology to transonic transport-type wind planforms. Each involved using state-of-the-art computational methods to design three-dimensional wing contours which generate significant runs of favorable pressure gradients. The first program supported the Variable Sweep Transition Flight Experiment and involves design of a full-span glove which extends from the leading edge to the spoiler hinge line on the upper surface of an F-14 outer wing panel. Boundary-layer and static-pressure data will be measured on this design during the supporting wind-tunnel and flight tests. These data will then be analyzed and used to infer the relationship between crossflow and Tollmein-Schlichting disturbances on laminar boundary-layer transition. A wing was designed computationally for a corporate transport aircraft in the second program. The resulting wing design generated favorable pressure gradients from the leading edge aft to the mid-chord on both upper and lower surfaces at the cruise design point. Detailed descriptions of the computational design approach are presented along with the various constraints imposed on each of the designs. Wing surface pressure distributions, which support the design objective and were derived from transonic three-dimensional analyses codes, are also presented. Current status of each of the research programs is included in the summary

    Age determination of the sixgill shark from hard parts using a series of traditional and novel approaches

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    Necessary to the management of any species of fish is the ability to determine age in individuals. Age information is used to establish growth rates, longevity, age at maturity, and population age structure, and to predict how population demographics will change over time. For most species of fish, reliable aging techniques have been in use since the early 20th century. Most boney fish are aged by counting bands of calcium phosphate hydroxyapatite that form over time in skeletal hard parts such as otoliths, fin-spines, and scales, which can be used as proxies for age in years. Fishes in the Class Elasmobranchii lack otoliths and have skeletons composed of cartilage, which often do not incorporate enough calcium to enable enumeration by traditional aging methods that rely on light microscopy, in some cases aided by enhancement techniques such as histological staining. For these fishes, alternative methods and aging structures are used to identify and enumerate annual patterns in calcium deposition. The aging structure of choice for most elasmobranches is the vertebral centrum, where bands of calcium are deposited that can be used as proxies for age in years. A few deep-dwelling species of Elasmobranchii, such as the sixgill shark (Hexanchus griseus,) have as yet defied efforts at age determination, inhibiting efforts to implement science-based management plans. This study has attempted to identify alternative aging structures that may incorporate seasonally-mediated concentrations of elements or isotopes into cartilage. Once identified, these structures were subjected to two recently developed methods of elemental microanalysis, energy dispersive X-ray spectroscopy (EDAX), and laser ablation, inductively-coupled, plasma mass spectrometry (LA-ICP-MS), in an effort to develop an aging method for H. griseus, and potentially other poorly calcified elasmobranchs. In addition, it has also used two traditional, histological staining methods, Von Kossa\u27s AgNO3, and Alizarin Red-S and applied them to these non-traditional aging structures. This study identified regions within the cartilaginous skeleton of H. griseus that lay down systematic banding patterns. These patterns were visually detected using AgNO3 staining enhanced light microscopy, as well as by periodic oscillations in isotopic concentrations for 24Mg, 88Sr, 107Ag, and 109Ag that were detected through the use of LA-ICP-MS. Future research in this field will need to verify if these bands are deposited on an annual basis. Methodologies must be developed for verification, and validation of these procedures to determine if the band patterns identified by either of these methods have utility for age determination in this and other poorly calcified species of elasmobranchs

    The study of the turbulent burning velocity by imaging the wrinkled flame surface

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76129/1/AIAA-2002-482-348.pd

    Improving chronic disease prevention and screening in primary care: results of the BETTER pragmatic cluster randomized controlled trial.

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    BackgroundPrimary care provides most of the evidence-based chronic disease prevention and screening services offered by the healthcare system. However, there remains a gap between recommended preventive services and actual practice. This trial (the BETTER Trial) aimed to improve preventive care of heart disease, diabetes, colorectal, breast and cervical cancers, and relevant lifestyle factors through a practice facilitation intervention set in primary care.MethodsPragmatic two-way factorial cluster RCT with Primary Care Physicians' practices as the unit of allocation and individual patients as the unit of analysis. The setting was urban Primary Care Team practices in two Canadian provinces. Eight Primary Care Team practices were randomly assigned to receive the practice-level intervention or wait-list control; 4 physicians in each team (32 physicians) were randomly assigned to receive the patient-level intervention or wait-list control. Patients randomly selected from physicians' rosters were stratified into two groups: 1) general and 2) moderate mental illness. The interventions involved a multifaceted, evidence-based, tailored practice-level intervention with a Practice Facilitator, and a patient-level intervention involving a one-hour visit with a Prevention Practitioner where patients received a tailored 'prevention prescription'. The primary outcome was a composite Summary Quality Index of 28 evidence-based chronic disease prevention and screening actions with pre-defined targets, expressed as the ratio of eligible actions at baseline that were met at follow-up. A cost-effectiveness analysis was conducted.Results789 of 1,260 (63%) eligible patients participated. On average, patients were eligible for 8.96 (SD 3.2) actions at baseline. In the adjusted analysis, control patients met 23.1% (95% CI: 19.2% to 27.1%) of target actions, compared to 28.5% (95% CI: 20.9% to 36.0%) receiving the practice-level intervention, 55.6% (95% CI: 49.0% to 62.1%) receiving the patient-level intervention, and 58.9% (95% CI: 54.7% to 63.1%) receiving both practice- and patient-level interventions (patient-level intervention versus control, P < 0.001). The benefit of the patient-level intervention was seen in both strata. The extra cost of the intervention was 26.43CAN(9526.43CAN (95% CI: 16 to $44) per additional action met.ConclusionsA Prevention Practitioner can improve the implementation of clinically important prevention and screening for chronic diseases in a cost-effective manner

    Optical Breath Gas Extravehicular Activity Sensor for the Advanced Portable Life Support System

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    The infrared gas transducer used during extravehicular activity (EVA) in the extravehicular mobility unit (EMU) measures and reports the concentration of carbon dioxide (CO2) in the ventilation loop. It is nearing its end of life and there are a limited number remaining. Meanwhile, the next generation advanced portable life support system (PLSS) now being developed requires CO2 sensing technology with performance beyond that presently in use. A laser diode (LD) spectrometer based on wavelength modulation spectroscopy (WMS) is being developed to address both applications by Vista Photonics, Inc. Accommodation within space suits demands that optical sensors meet stringent size, weight, and power requirements. Version 1.0 devices were delivered to NASA Johnson Space Center (JSC) in 2011. The sensors incorporate a laser diode based CO2 channel that also includes an incidental water vapor (humidity) measurement. The prototypes are controlled digitally with a field-programmable gate array (FPGA)/microcontroller architecture. Version 2.0 devices with improved electronics and significantly reduced wetted volumes were delivered to JSC in 2012. A version 2.5 upgrade recently implemented wavelength stabilized operation, better humidity measurement, and much faster data analysis/reporting. A wholly reconfigured version 3.0 will maintain the demonstrated performance of earlier versions while being backwards compatible with the EMU and offering a radiation tolerant architecture

    Exercise-based cardiac rehabilitation improves exercise capacity and health-related quality of life in people with atrial fibrillation: a systematic review and meta-analysis of randomised and non-randomised trials

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    Objective: The aim of this study was to undertake a contemporary review of the impact of exercise-based cardiac rehabilitation (CR) targeted at patients with atrial fibrillation (AF). Methods: We conducted searches of PubMED, EMBASE and the Cochrane Library of Controlled Trials (up until 30 November 2017) using key terms related to exercise-based CR and AF. Randomised and non-randomised controlled trials were included if they compared the effects of an exercise-based CR intervention to a no exercise or usual care control group. Meta-analyses of outcomes were conducted where appropriate. Results: The nine randomised trials included 959 (483 exercise-based CR vs 476 controls) patients with various types of AF. Compared with control, pooled analysis showed no difference in all-cause mortality (risk ratio (RR) 1.08, 95% CI 0.77 to 1.53, p=0.64) following exercise-based CR. However, there were improvements in health-related quality of life (mean SF-36 mental component score (MCS): 4.00, 95% CI 0.26 to 7.74; p=0.04 and mean SF-36 physical component score: 1.82, 95% CI 0.06 to 3.59; p=0.04) and exercise capacity (mean peak VO2: 1.59 ml/kg/min, 95% CI 0.11 to 3.08; p=0.04; mean 6 min walk test: 46.9 m, 95% CI 26.4 to 67.4; p<0.001) with exercise-based CR. Improvements were also seen in AF symptom burden and markers of cardiac function. Conclusions: Exercise capacity, cardiac function, symptom burden and health-related quality of life were improved with exercise-based CR in the short term (up to 6 months) targeted at patients with AF. However, high-quality multicentre randomised trials are needed to clarify the impact of exercise-based CR on key patient and health system outcomes (including health-related quality of life, mortality, hospitalisation and costs) and how these effects may vary across AF subtypes

    Epitope mapping of antigenic MUC1 peptides to breast cancer antibody fragment B27.29: a heteronuclear NMR study

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    ABSTRACT: MUC1 mucin is a breast cancer-associated transmembrane glycoprotein, of which the extracellular domain is formed by the repeating 20-amino acid sequence GVTSAPDTRPAPGSTAPPAH. In neoplastic breast tissue, the highly immunogenic sequence PDTRPAP (in bold above) is exposed. Antibodies raised directly against MUC1-expressing tumors offer unique access to this neoplastic state, as they represent immunologically relevant "reverse templates" of the tumor-associated mucin. In a previous study [Grinstead, J. S., et al. (2002) Biochemistry 41, 9946-9961], 1 H NMR methods were used to correlate the effects of cryptic glycosylation outside of the PDTRPAP core epitope sequence on the recognition and binding of Mab B27.29, a monoclonal antibody raised against breast tumor cells. In the study presented here, isotope-edited NMR methods, including 15 N and 13 C relaxation measurements, were used to probe the recognition and binding of the PDTRPAP epitope sequence to Fab B27.29. Two peptides were studied: a one-repeat MUC1 16mer peptide of the sequence GVTSAPDTRPAPGSTA and a two-repeat MUC1 40mer peptide of the sequence (VTSAPDTRPAPGSTAPPAHG) 2 . 15 N and 13 C NMR relaxation parameters were measured for both peptides free in solution and bound to Fab B27.29. The 13 C R T 1 values best represent changes in the local correlation time of the peptide epitope upon binding antibody, and demonstrate that the PDTRPAP sequence is immobilized in the antibody-combining site. This result is also reflected in the appearance of the 15 N-and 13 C-edited HSQC spectra, where line broadening of the same peptide epitope resonances is observed. The PDTRPAP peptide epitope expands upon the peptide epitope identified previously in our group as PDTRP by homonuclear NMR experiments [Grinstead, J. S., et al. (2002) Biochemistry 41, 9946-9961], and illustrates the usefulness of the heteronuclear NMR experiments. The implications of these results are discussed within the context of MUC1 breast cancer vaccine design. Mucins have been implicated as targets for vaccine development in cancers of the breast, colon, pancreas, lung, and ovary because of the differences between normal and tumor-associated mucin (1-4). Mucin 1 (MUC1) 1 is a large transmembrane glycoprotein that is expressed on the ductal surface of epithelial cells. The extracellular region of the protein consists of a variable number of tandem repeats (VNTR) of the 20-amino acid sequence (GVTSAPDTR-PAPGSTAPPAH) n , extensively O-glycosylated at threonine and serine sites with large, branched sugars (5-8). However, in the tumor-associated state, MUC1 becomes an autoantigen as a result of incomplete glycosylation and the sparse distribution of remaining carbohydrate structures (9). The reduced level of glycosylation is believed to result in the exposure of a highly immunogenic core peptide sequence (PDTRP in bold above) (10), identified as the immunodominant B-cell epitope from monoclonal antibody studies in mice Many different clinical trials have been undertaken over the past few years to assess the ability of MUC1-based vaccines to generate strong and cytotoxic anti-MUC1 immune responses against the solid MUC1-expressing tumor. Several of these trials have explored the use of MUC1 peptides coupled to different haptens, keyhole limpet hemocyanin, oxidized mannan, and glutathione S-transferase (4). In addition, at least two different vaccine trials have used MUC1-associated antigenic sugars (without peptide) (22). Other more recent clinical trials have utilized peptide-or DNA-pulsed dendritic cells as vaccine vectors, attempting to capitalize on the superior immune activation by these antigen-presenting cells. Dendritic cells pulsed with either MUC1 peptides or cDNA have been able to generate limited CD8 + T-cell responses to solid breast tumor

    Minimum Aerosol Layer Detection Sensitivities and Their Subsequent Impacts on Aerosol Optical Thickness Retrievals in CALIPSO Level 2 Data Products

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    Due to instrument sensitivities and algorithm detection limits, level 2 (L2) Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) 532 nm aerosol extinction profile retrievals are often populated with retrieval fill values (RFVs), which indicate the absence of detectable levels of aerosol within the profile. In this study, using 4 years (20072008 and 20102011) of CALIOP version 3 L2 aerosol data, the occurrence frequency of daytime CALIOP profiles containing all RFVs (all-RFV profiles) is studied. In the CALIOP data products, the aerosol optical thickness (AOT) of any all-RFV profile is reported as being zero, which may introduce a bias in CALIOP-based AOT climatologies. For this study, we derive revised estimates of AOT for all-RFV profiles using collocated Moderate Resolution Imaging Spectroradiometer (MODIS) Dark Target (DT) and, where available, AErosol RObotic NEtwork (AERONET) data. Globally, all-RFV profiles comprise roughly 71 % of all daytime CALIOP L2 aerosol profiles (i.e., including completely attenuated profiles), accounting for nearly half (45 %) of all daytime cloud-free L2 aerosol profiles. The mean collocated MODIS DT (AERONET) 550 nm AOT is found to be near 0.06 (0.08) for CALIOP all-RFV profiles. We further estimate a global mean aerosol extinction profile, a so-called noise floor, for CALIOP all-RFV profiles. The global mean CALIOP AOT is then recomputed by replacing RFV values with the derived noise-floor values for both all-RFV and non-all-RFV profiles. This process yields an improvement in the agreement of CALIOP and MODIS over-ocean AOT

    Space Shuttle Orbiter Structures and Mechanisms

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    The Space Shuttle Orbiter has performed exceptionally well over its 30 years of flight experience. Among the many factors behind this success were robust, yet carefully monitored, structural and mechanical systems. From highlighting key aspects of the design to illustrating lessons learned from the operation of this complex system, this paper will attempt to educate the reader on why some subsystems operated flawlessly and why specific vulnerabilities were exposed in others. Specific areas to be covered will be the following: high level configuration overview, primary and secondary structure, mechanical systems ranging from landing gear to the docking system, and windows
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