The effect of a particle travelling through a laminar boundary layer on transition

This study investigates how a particle travelling through an initially laminar boundary layer can lead to its breakdown to turbulence With increasing kerosene costs and an awareness of limited available oil reserves, laminar flow technologies are again being considered to realize the necessary efficiency increases of aircraft, and more detailed information on the operational issues is required. The adverse impact of flying through cirrus clouds has been simplified to the effect of a single particle on a laminar boundary layer over a zero-pressure gradient flat plate. First results indicate that the critical values could be substantially smaller than initially assumed

Slight stress does not lower critical thermal maximums in hatchery-reared rainbow trout

This study evaluated the physiological response of rainbow trout to various initial stressors, either confinement or electroshock, followed by a heat challenge in order to determine how the critical thermal maximum of the fish was affected by the intensity of the initial stressor. Plasma cortisol and glucose levels were determined following the initial stressor and the challenge stressor. The initial stressor induced a typical, but mild, response by increasing cortisol levels to 68 ng/mL for the electroshocked group and 112 ng/mL for the 60-minute confinement group. Although these increases are significantly different (P\u3c.05) from the baseline group (9 ng/mL) they are lower than values observed in the literature for similar stressors. The challenge stressor did not induce any further cortisol increase in fish receiving an initial stress, and in fact decreased significantly (P\u3c.05). The electroshock-challenged group had a significantly higher critical thermal maximum (30 C), but this was only 0.9 C higher than the lowest critical thermal maximum

Assessment of the selectivity of proteinuria by gel filtration

The selectivity of proteinuria was assessed in 25 patients by a gel filtration technique utilising a G 200 Sephadex column. The results were compared with those obtained using gel diffusion and immunoprecipitation to assess selectivity. In five patients, where the protein excretion was less than 1.0 g. per day, the results obtained by gel filtration through Sephadex were found to be suspect. In the remaining 20 patients, where the protein excretion was over 1.0 g. per day, the relationship between the gel filtration selectivity and that determined by immunoprecipitation could be expressed as a straight line passing through the origin. The correlation coefficient for this line (0.84) was highly significant statistically.The selectivities obtained on gel filtration were assessed in the light of the findings on renal biopsy. Two of the twenty patients with proteinuria of over 1.0 g. per day had minimal lesion glomerulonephritis. These patients also had the two highest selectivities in the series.Three of the patients studied had chronic renal failure. These patients had the lowest, the second lowest, and the fifth lowest selectivities of the series.Good renal function and minimal glomerular damage appearJto be associated with selective proteinuria, while poor renal function and severe glomerular damage appeared to be associated with unselective proteinuria.Five patients with selective proteinuria were treated with steroids. In two cases the proteinuria disappeared. In a third it fell to trace amounts.Ten patients with intermediate or unselective proteinuria were treated with steroids. In only one case was there a significant reduction of proteinuria

Glomerular selective permeability to protein, dextran, and polyvinylpyrrolidone in health and disease

This thesis presents the results of six year's work on macromolecular clearance determinations.This work is placed in context by an introductory review of literature relating to the physiology of protein excretion. Early concepts of the mechanisms involved in proteinuria are discussed. Among the studies reviewed are observations on micropuncture of the glomeruli and proximal tubules, clearance experiments, stop-flow analyses, histochemicai findings, and electron microscopy studies, It is concluded from this review of the literature that some protein is filtered at the glomeruli, but that in health virtually all of this is reabsorbed by a process which, for albumin and molecules larger than albumin, is non-selective, Reasons are given for the opinion that tubular secretion of protein is unimportant.The immunodiffusion method used in protein clearance studies is then described, along with the gel filtration technique used to determine protein, dextran, and polyvinylpyrrolidone clearances. The errors involved in these techniques are discussed.Results are presented for protein clearance studies carried out in parallel by the two techniques. From an analysis of these results it is concluded that in patients excreting over 1.OG of protein daily, -K (the index of protein selectivity by the immuno-diffusion technique) is related to Δ (the index of selectivity by the gel filtration technique) by the formula Δ = 0.73 (-K).Dextran and protein selectivity values are compared in normal subjects, in proteinuria induced by plasma infusion, and in a variety of disease states. In minimal lesion glomerulonephritis, membranous glomerulonephritis and in induced proteinuria, dextran and protein selectivity values are in substantial agreement. In normal subjects under normal conditions, in proliferative glomerulonephritis, in postural proteinuria, and in acute ischaemic renal failure, dextran selectivity values are consistently and considerably higher than protein selectivity values. These findings are explained in terms of differences in the renal handling of protein and dextran and in terras of differences in the mechanisms involved in proteinuria in the various conditions described. From the experiments on induced proteinuria it is concluded that the filtration of protein at the normal glomerulus, like that of dextran, is highly selective.The results of protein selectivity determinations in 207 patients with major proteinuria are presented and related to the histological diagnoses. Selectivity values in minimal lesion glomerulonephritis are consistently high, while in patients with renal failure proteinuria is uniformly unselective.The relationship between protein selectivity and prognosis is assessed in 197 patients. A very high selectivity (-K over 2.6) is associated with a very good prognosis (3 year survival with functioning kidneys of 96%). A very low selectivity (-K less than 1.4) is associated with a poor prognosis (3 year survival of 27%).The relationship between selectivity and responsiveness to steroid therapy is assessed in 82 treated patients. In our experience, a selectivity value of 2.0 or less is consistently associated with unresponsiveness to steroid therapy• While prompt abolition of proteinuria following steroid therapy is to be expected only in patients with minimal lesion glomerulonephritis, comparison of the outcome at 8 weeks in 30 treated proliferatives with findings at 8 weeks in 26 untreated controls with similar histology shows a significant reduction in proteinuria in response to steroids in patients with proliferative histology and selective proteinuria

Ancient Egypt 1916 Part 2

Part 2 of the 1916 Ancient Egypt books. Contents include the Gorringe collection, an early figure of Taurt, Egypt in the Grail Romance, and the queenly title, XXIInd dynasty.https://knowledge.e.southern.edu/kweeks_coll/1006/thumbnail.jp

Planetary systems around close binary stars: the case of the very dusty, Sun-like, spectroscopic binary BD+20 307

Field star BD+20 307 is the dustiest known main sequence star, based on the fraction of its bolometric luminosity, 4%, that is emitted at infrared wavelengths. The particles that carry this large IR luminosity are unusually warm, comparable to the temperature of the zodiacal dust in the solar system, and their existence is likely to be a consequence of a fairly recent collision of large objects such as planets or planetary embryos. Thus, the age of BD+20 307 is potentially of interest in constraining the era of terrestrial planet formation. The present project was initiated with an attempt to derive this age using the Chandra X-ray Observatory to measure the X-ray flux of BD+20 307 in conjunction with extensive photometric and spectroscopic monitoring observations from Fairborn Observatory. However, the recent realization that BD+20 307 is a short period, double-line, spectroscopic binary whose components have very different lithium abundances, vitiates standard methods of age determination. We find the system to be metal-poor; this, combined with its measured lithium abundances, indicates that BD+20 307 may be several to many Gyr old. BD+20 307 affords astronomy a rare peek into a mature planetary system in orbit around a close binary star (because such systems are not amenable to study by the precision radial velocity technique).Comment: accepted for ApJ, December 10, 200

Comparison of Interactions Between Control and Mutant Macrophages

This paper presents a preliminary study on macrophages migration in Drosophila embryos, comparing two types of cells. The study is carried out by a framework called macrosight which analyses the movement and interaction of migrating macrophages. The framework incorporates a segmentation and tracking algorithm into analysing motion characteristics of cells after contact. In this particular study, the interactions between cells is characterised in the case of control embryos and Shot3 mutants, where the cells have been altered to suppress a specific protein, looking to understand what drives the movement. Statistical significance between control and mutant cells was found when comparing the direction of motion after contact in specific conditions. Such discoveries provide insights for future developments in combining biological experiments to computational analysis

Ancient Egypt 1922 Part 3

Part 3 of the 1922 Ancient Egypt books. Contents include Hittite letters on Egypt, heddle-jacks of looms, loom weights in Egypt, and a discussion of Nebti Sma.https://knowledge.e.southern.edu/kweeks_coll/1020/thumbnail.jp