Experimental Study of Cavitation and Hydraulic Flip Effects on Liquid Jet Characteristics into Crossflows

In this work, the effects of orifice internal flow, such as cavitation and hydraulic flip, on the breakup processes of the liquid jet injected perpendicularly into subsonic crossflows were studied experimentally. To provide several conditions for orifice internal flow, different orifice diameters, injection pressure differentials, and shapes (sharp and round) of the orifice entrance were used. Photographs of liquid flow inside the orifice confirmed the internal flow condition. A stroboscopic light was used to measure the liquid column breakup lengths and the liquid column trajectories. The results showed that the liquid column trajectories in noncavitation flows and cavitation flows had a similar trend, but the liquid column trajectories in hydraulic lip flows had different results because the surface of the liquid in the hydraulic flip flows was detached from the inner wall of the orifice hole. As cavitation bubbles developed inside the sharp-edged orifice, the liquid jet became more turbulent and unsteady. Therefore, the liquid column breakup lengths in the cavitation flows were shorter than those in noncavitation flows. In the hydraulic flip, the breakup lengths had smaller values because the liquid jet diameter was smaller than the orifice diameter, and the acceleration waves occurring on the liquid column spread upstream of the orifice exit, then the breakup process on the liquid jet started from the orifice entrance

Airway microbiome in adult survivors of extremely preterm birth: the EPICure study

Bronchopulmonary Dysplasia(BPD) is a major complication of preterm birth that leads to lifelong respiratory morbidity. The EPICure study has investigated the longitudinal health outcomes of infants born extremely preterm (<26 weeks-gestation). Our aim was to characterise the airway microbiome in young adults born extremely preterm (EP), with and without neonatal BPD, in comparison to matched term-born controls.Induced sputum was collected from 92 young adults age 19 years (51 EP and 41 controls). Typical respiratory pathogens were detected using quantitative-PCR. 16S-rRNA gene sequencing was completed on 74 samples (29 EP with BPD, 9 EP without BPD and 36 controls).The preterm group with BPD had the least diverse bacterial communities. The relative-abundance of Bacteriodetes, particularly Prevotella melaninogenica was significantly lower in the preterm group compared to controls. This decline was balanced by a nonsignificant increase in Firmicutes. Total Prevotella relative-abundance correlated with FEV1 z-score (ρ=0.272; p<0.05). Typical respiratory pathogens loads and prevalence were similar between groups.In conclusion, extremely preterm birth is associated with a significant dysbiosis in airway microbiome in young adulthood regardless of neonatal BPD status. This is characterised by a shift in the community composition away from Bacteriodetes as manifested in a significant drop in Prevotella relative-abundance

Steady Flow of Purely Viscous Shear-Thinning Fluids in a 1:3 Planar Gradual Expansion

Laminar flow of non-Newtonian fluid (shear-thinning) through a 1:3 planar gradual expansion is numerically investigated, for various Power-Law index (0.6, 0.8 and 1.0) and expansion angles (15, 30, 45, 60 and 90°) at different generalized Reynolds number (1 ≤ Reg ≤ 400). The study of these parameters effect on the flow pattern allowed the determination of the two critical generalized Reynolds numbers (Regcr1 and Regcr2), which correspond to the transition from the symmetric to the asymmetric flow and the appearance of the third recirculation zone respectively. The results showed that decreasing the Power-Law index or the expansion angle stabilizes the flow by increasing significantly the two critical generalized Reynolds numbers. In order to predict the two critical generalized Reynolds numbers, two correlations have been proposed

A Burgessian critique of nominalistic tendencies in contemporary mathematics and its historiography

We analyze the developments in mathematical rigor from the viewpoint of a Burgessian critique of nominalistic reconstructions. We apply such a critique to the reconstruction of infinitesimal analysis accomplished through the efforts of Cantor, Dedekind, and Weierstrass; to the reconstruction of Cauchy's foundational work associated with the work of Boyer and Grabiner; and to Bishop's constructivist reconstruction of classical analysis. We examine the effects of a nominalist disposition on historiography, teaching, and research.Comment: 57 pages; 3 figures. Corrected misprint

The Acute Environment, Rather than T Cell Subset Pre-Commitment, Regulates Expression of the Human T Cell Cytokine Amphiregulin

Cytokine expression patterns of T cells can be regulated by pre-commitment to stable effector phenotypes, further modification of moderately stable phenotypes, and quantitative changes in cytokine production in response to acute signals. We showed previously that the epidermal growth factor family member Amphiregulin is expressed by T cell receptor-activated mouse CD4 T cells, particularly Th2 cells, and helps eliminate helminth infection. Here we report a detailed analysis of the regulation of Amphiregulin expression by human T cell subsets. Signaling through the T cell receptor induced Amphiregulin expression by most or all T cell subsets in human peripheral blood, including naive and memory CD4 and CD8 T cells, Th1 and Th2 in vitro T cell lines, and subsets of memory CD4 T cells expressing several different chemokine receptors and cytokines. In these different T cell types, Amphiregulin synthesis was inhibited by an antagonist of protein kinase A, a downstream component of the cAMP signaling pathway, and enhanced by ligands that increased cAMP or directly activated protein kinase A. Prostaglandin E2 and adenosine, natural ligands that stimulate adenylyl cyclase activity, also enhanced Amphiregulin synthesis while reducing synthesis of most other cytokines. Thus, in contrast to mouse T cells, Amphiregulin synthesis by human T cells is regulated more by acute signals than pre-commitment of T cells to a particular cytokine pattern. This may be appropriate for a cytokine more involved in repair than attack functions during most inflammatory responses