Sodium absorption stimulator prostasin (PRSS8) has an anti-inflammatory effect via downregulation of TLR4 signaling in inflammatory bowel disease.

BACKGROUND:Prostasin (PRSS8) is a stimulator of epithelial sodium transport. In this study, we evaluated alteration of prostasin expression in the inflamed mucosa of patients with inflammatory bowel disease (IBD) and investigated the role of prostasin in the gut inflammation.METHODS:Prostasin expression was evaluated by immunohistochemical staining. Dextran sodium sulfate (DSS)-colitis was induced in mice lacking prostasin specifically in intestinal epithelial cells (PRSS8ΔIEC mice).RESULTS:In colonic mucosa of healthy individuals, prostasin was strongly expressed at the apical surfaces of epithelial cells, and this was markedly decreased in active mucosa of both ulcerative colitis and Crohn\u27s disease. DSS-colitis was exacerbated in PRSS8ΔIEC mice compared to control PRSS8lox/lox mice. Toll-like receptor4 (TLR4) expression in colonic epithelial cells was stronger in DSS-treated PRSS8ΔIEC mice than in DSS-treated PRSS8 lox/lox mice. NF-κB activation in colonic epithelial cells was more pronounced in DSS-treated PRSS8ΔIEC mice than in DSS-treated PRSS8lox/lox mice, and the mRNA expression of inflammatory cytokines was significantly higher in DSS-treated PRSS8ΔIEC mice. Broad-spectrum antibiotic treatment completely suppressed the exacerbation of DSS-colitis in PRSS8ΔIEC mice. The mRNA expression of tight junction proteins and mucosal permeability assessed using FITC-dextran were comparable between DSS-treated PRSS8lox/lox and DSS-treated PRSS8ΔIEC mice.CONCLUSION:Prostasin has an anti-inflammatory effect via downregulation of TLR4 expression in colonic epithelial cells. Reduced prostasin expression in IBD mucosa is linked to the deterioration of local anti-inflammatory activity and may contribute to the persistence of mucosal inflammation

Numerical and Experimental Study of Topographic Speed-Up Effects in Complex Terrain

Our research group is developing computational fluid dynamics (CFD)-based software for wind resource and energy production assessments in complex terrain called RIAM-COMPACT (Research Institute for Applied Mechanics, Kyushu University (RIAM)-Computational Prediction of Airflow over Complex Terrain), based on large eddy simulation (LES). In order to verify the prediction accuracy of RIAM-COMPACT, we conduct a wind tunnel experiment that uses a two-dimensional steep ridge model with a smooth surface. In the wind tunnel experiments, airflow measurements are performed using an I-type hot-wire probe and a split film probe that can detect forward and reverse flows. The results of the numerical simulation by LES are in better agreement with the wind tunnel experiment using the split film probe than the results of the wind tunnel experiment using the I-type hot wire probe. Furthermore, we calculate that the two-dimensional ridge model by changing the length in the spanwise direction, and discussed the instantaneous flow field and the time-averaged flow field for the three-dimensional structure of the flow behind the model. It was shown that the eddies in the downwind flow-separated region formed behind the two-dimensional ridge model were almost the same size in all cases, regardless of the difference in the length in the spanwise direction. In this study, we also perform a calculation with a varying inflow shear at the inflow boundary. It was clear that the size in the vortex region behind the model was almost the same in all the calculation results, regardless of the difference in the inflow shear. Next, we conduct wind tunnel experiments on complex terrain. In the wind tunnel experiments using a 1/2800 scale model, the effect of artificial irregularities on the terrain surface did not significantly appear on the airflow at the hub height of the wind turbine. On the other hand, in order to investigate the three-dimensional structure of the airflow in the swept area in detail, it was clearly shown that LES using a high-resolution computational grid is very effective

GULLY HEAD RETREAT OF AWACH-KANO GULLIES, NYANZA PROVINCE, KENYA: FIELD MEASUREMENTS ANF PIXED-BASED UPALOPE CATCHMENT ASSESSMENT

Gully erosion is a form of land degradation. Soil loss from croplands and residential areas and damage to human infrastructure caused by gully headcut retreat are particularly serious issues for developing countries in sub-Saharan Africa. We focused on the severe gully headcut retreat that incises agricultural land at the foot of the Kavirondo Rift escarpment in western Kenya. Between 2003 and 2004, measurements of the gully headcut retreat were taken. We investigated the topography, geology, and vegetation cover of the upslope catchment through field studies using remotely sensed imagery, analyzed using pixel-based data management. Analysis showed that factors sensitive to runoff were dominant and different overland flow paths caused different kinds of gully headcut retreat. Our pixel-based catchment assessment is a useful measure in the risk management of gully headcut retreat in this region

大気境界層の概要と室内模擬実験 : 平成13年度九州大学教室系技術職員研修ポスターセッション発表

1.はじめに / 2.大気境界層と大気の流れ / 3.温度成層風洞における模撮実験 / 4.実験例 : 三宅島周辺流れの可視

風洞風速の断面内調節

1.はじめに / 2.断面肉風速変化の手法 / 2.1 網方式による手法 / 2.2 棚方式による手法 / 3.まと

密度成層風洞による大気の流れの再現

1.はじめに / 2-1.孤立峰周りの流れ / 2-2.山脈を越える涜れ / 3.まと