No abstract

Rationale: The presence of inflammatory cells on bronchoalveolar lavage is often used to predict disease activity and the need for therapy in systemic sclerosis-associated interstitial lung disease. Objectives: To evaluate whether lavage cellularity identifies distinct subsets of disease and/or predicts cyclophosphamide responsiveness. Methods: Patients underwent baseline lavage and/or high-resolution computed tomography as part of a randomized placebo-controlled trial of cyclophosphamide versus placebo (Scleroderma Lung Study) to determine the effect of therapy on forced vital capacity. Patients with 3% or greater polymorphonuclear and/or 2% or greater eosinophilic leukocytes on lavage and/or ground-glass opacification on computed tomography were eligible for enrollment. Measurements and Main Results: Lavage was performed in 201 individuals, including 141 of the 158 randomized patients. Abnormal cellularity was present in 101 of these cases (71.6%) and defined a population with a higher percentage of men (P 5 0.04), more severe lung function, including a worse forced vital capacity (P 5 0.003), worse total lung capacity (P 5 0.005) and diffusing capacity of the lung for carbon monoxide (P 5 0.004), more extensive ground-glass opacity (P 5 0.005), and more extensive fibrosis in the right middle lobe (P 5 0.005). Despite these relationships, the presence or absence of an abnormal cell differential was not an independent predictor of disease progression or response to cyclophosphamide at 1 year (P 5 not significant). Conclusions: The presence of an abnormal lavage in the Scleroderma Lung Study defined patients with more advanced interstitial lung disease but added no additional value to physiologic and computed tomography findings as a predictor of progression or treatment response. Clinical trial registered with www.clinicaltrials.gov (NCT 000004563).

This paper describes the design and performance testing of a vibration isolation and suppression system (VISS) which can be used to isolate a precision payload from spacecraft borne disturbances. VISS utilizes six hybrid isolation struts in a hexapod configuration. Central to the concept is a novel hybrid actuation concept which provides both passive isolation and active damping. The passive isolation is provided using a flight proven D-strut design. The passive design is supplemented by a voice coil based active system. The active system is used to enhance the performance of the passive isolation system at lower frequencies, and provide the capability to steer the payload.

No abstract

No abstract

No abstract

While many bio-inspired flapping wing micro air vehicle wing designs continue to be conceived and studied in earnest, a general consensus of which physical attributes of the biological entity are important for flight is still at-large. It is proposed herein that the eigenstructure of the wing should figure prominently among rigorous engineering metrics for guiding flapping wing micro air vehicle wing designs at the scales of large insects. With virtually no compelling work done in this area to date, the method and results of system identification tests for the forewings of a representative sample of hawkmoth (Manduca Sexta) are presented, revealing the underlying structural nature of this incredibly agile flyer's wings. Despite their inherent biological variability, these wings show very little variability in eigenstructure which may suggest it as a critical attribute for robust flight. Further supporting this hypothesis, the wings of four other insect species are briefly examined and show remarkable similarity with the hawkmoth wing's eigenstructure. INTRODUCTIONWhile the lure of the micro air vehicle (MAV) stems from its promise of operational capabilities that have been well documented [1,2,3,4], the attraction of the MAV within the research community is at least partly attributable to its low cost of entry into its field of study. Indeed, the large and expensive R&D infrastructure associated with larger scale and conventional aircraft development can be reduced to small indoor flight arenas, bench top engineering equipment and instrumentation, as well as the vast and affordable computing space offered by desktop computers, as illustrated in [5]. Arguably, it has been this ease of entry that has enabled the worldwide explosion in MAV related research over the past 10-15 years [6]. As a review of literature will reveal, from the first coining of "MAV" by Francis and McMichael [1], the locus of MAV related flight research quickly migrated toward bio-inspired wing designs and almost exclusively to flapping wing designs for hummingbird-size and smaller variants to include larger species of flying insect. While there are physical and operational arguments to reject more conventional fixed or rotary wing designs at MAV scales, perhaps the most compelling reason for partiality toward flapping wings is the perception that conceiving a design capable of rivaling the elegance of the solution that nature has already provided for flight at small scales is unlikely. Though this is intuitively compelling, bio-inspired design is not without fault.This paper briefly presents a case for tempering MAV flight researchers' zeal for bio-inspired wing design with a consideration of those features of natural design that may be important, if not required, for successful flapping flight, especially at large insect scales. This consideration naturally leads to an argument for why the eigenstructure of the insect wing, having neither skeletal nor musculature features, should figure prominently among MAV wing design parameters....

No abstract