2,803 research outputs found
An Experimental Investigation Into the Performance of a Flush Water-Jet Inlet
An experimental investigation of the flow within a generic flush type water-jet inlet has
been carried out to identify the principal flow features and provide a basis for development
of computational fluid dynamics (CFD) models. Tests were performed in a
cavitation tunnel with the model inlet fitted to the test section ceiling, and effects of
thickening the ingested tunnel wall boundary layer were investigated. The model was
fitted with a range of instrumentation to investigate the ramp pressure distribution and
boundary layer development, lip incidence, and pump face flow properties. Observations
of lip and duct cavitation inception and behavior were also made. The results
showed the inlet performance to be generally improved with the ingestion of a thicker
boundary layer. The thickened boundary layer significantly reduced ramp boundary
layer separation and distortion of flow at the notional pump face. However, a greater
range of lip incidence occurred with the thickened boundary layer with consequent
greater likelihood of lip separation and cavitation occurrence. Ideal lip incidence and
pump face flow uniformity occurred at flow parameters significantly different from
those for ideal pump face pressure recovery. Large developed cavities on the inlet lip
were observed for a range of conditions typical of conventional high-speed vessel
operation
AGER expression and alternative splicing in bronchial biopsies of smokers and never smokers
Abstract Cigarette smoking is one of the major risk factors for the development of chronic obstructive pulmonary disease (COPD). Evidence is accumulating that Receptor for Advanced Glycation-End products (RAGE)-signaling is a key pathway in the pathophysiology of COPD. To date, it is unknown how smoking affects RAGE expression. In the current study, we investigated the effect of smoking on AGER, the gene encoding RAGE, expression and on alternative splicing of AGER. To this end, we conducted RNA-Seq on bronchial biopsies for asymptomatic smokers (n = 36) and never smokers (n = 40). Total AGER gene expression was accessed using DESeq2, while alternative splicing was investigated by measuring the number of specific split reads spanning exon-exon junctions and the total split reads. One of the major isoforms of RAGE is endogenous soluble (es) RAGE, an anti-inflammatory decoy receptor, making up for approximately 10% of the total amount of soluble (s)RAGE. We found that smokers show decreased total gene expression of AGER in bronchial biopsies, while the relative abundance of the esRAGE isoform is increased. Furthermore, no difference in the serum levels of total sRAGE were observed between smokers and non-smokers. Our data indicates that smoking initiates a protective anti-inflammatory mechanism with decreased expression of the pro-inflammatory gene AGER and increased relative abundance of the anti-inflammatory isoform esRAGE
Sparsest factor analysis for clustering variables: a matrix decomposition approach
We propose a new procedure for sparse factor analysis (FA) such that each variable loads only one common factor. Thus, the loading matrix has a single nonzero element in each row and zeros elsewhere. Such a loading matrix is the sparsest possible for certain number of variables and common factors. For this reason, the proposed method is named sparsest FA (SSFA). It may also be called FA-based variable clustering, since the variables loading the same common factor can be classified into a cluster. In SSFA, all model parts of FA (common factors, their correlations, loadings, unique factors, and unique variances) are treated as fixed unknown parameter matrices and their least squares function is minimized through specific data matrix decomposition. A useful feature of the algorithm is that the matrix of common factor scores is re-parameterized using QR decomposition in order to efficiently estimate factor correlations. A simulation study shows that the proposed procedure can exactly identify the true sparsest models. Real data examples demonstrate the usefulness of the variable clustering performed by SSFA
Assessment of conjunctival, episcleral and scleral thickness in healthy individuals using anterior segment optical coherence tomography
Purpose: To determine the thickness of the conjunctiva, episclera and sclera in healthy individuals using anterior segment optical coherence tomography (AS-OCT).Methods: We prospectively included 107 healthy individuals of different age groups (18-39 years, 40-54 years, 55-69 years and >= 70 years). For each eye, AS-OCT scans of four quadrants (temporal, nasal, superior and inferior) were acquired. The thickness of the conjunctiva, episclera and sclera was measured for each scan. In addition, the axial length of both eyes was measured, and general characteristics, including smoking, allergies and contact lens use, were collected.Results: The mean conjunctival thickness was significantly different between the nasal and superior quadrants (87 +/- 30 mu m vs. 77 +/- 16 mu m; p < 0.001), as well as the superior and inferior quadrants (77 +/- 16 mu m vs. 86 +/- 19 mu m; p = 0.001). The mean episcleral thickness was larger in the superior (174 +/- 54 mu m) and inferior (141 +/- 43 mu m) quadrants, compared to the nasal (83 +/- 38 mu m) and temporal quadrants (90 +/- 44 mu m). The mean scleral thickness of the inferior quadrant was the largest (596 +/- 64 mu m), followed by the nasal (567 +/- 76 mu m), temporal (516 +/- 67 mu m) and superior (467 +/- 52 mu m) quadrants (all p < 0.001). The averaged scleral thickness increased 0.96 mu m per age year (0.41-1.47 mu m, p < 0.001).Conclusions: This study provides an assessment of the thickness of scleral and adjacent superficial layers in healthy individuals determined on AS-OCT, which could enable future research into the use of AS-OCT in diseases affecting the anterior eye wall
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