Calreticulin, a molecular chaperone involved in the folding of endoplasmic reticulum synthesized proteins, is also a shock protein induced by heat, food deprivation, and chemical stress. Mobilferrin, a cytosolic isoform of calreticulin, has been proposed to be an iron carrier for iron recently incoming into intestinal cells. To test the hypothesis that iron could affect calreticulin expression, we investigated the possible associations of calreticulin with iron metabolism. To that end, using Caco-2 cells as a model of intestinal epithelium, the mass and mRNA levels of calreticulin were evaluated as a function of the iron concentration in the culture media. Increasing the iron content in the culture from 1 to 20 microM produced an increase in calreticulin mRNA and a two-fold increase in calreticulin. Increasing iron also induced oxidative damage to proteins, as assessed by the formation of 4-hydroxy-2-nonenal adducts. Co-culture of cells with the antioxidants quercetin, dimethyltiourea and N-acetyl cysteine abolished both the iron-induced oxidative damage and the iron-induced increase in calreticulin. We postulate that the iron-induced expression of calreticulin is part of the cellular response to oxidative stress generated by iron.

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A series of sweeping jet-impingement experiments are conducted over a circular heated surface, with a main objective of understanding the impact of the unique flow field on the resulting heat transfer. The sweeping motion of the fluidic oscillator is influenced by the sweeping frequency and sweeping angle where each is directly dependent on the geometric design (i.e. internal feedback loops, mixing chamber, etc.). The target surface consists of a heated copper disk, where heater power is supplied to the bottom surface of the disk and adjusted until a differential of 30°C is obtained between the jet and target surface temperatures. An energy balance over the target surface temperatures provides a means for calculating area-averaged heat transfer rate, hence Nusselt number. An increase in the sweeping jet’s thermal inertia initiates an augmentation in heat transfer due to sweeping motion of the jet across the target surface. PIV data was acquired for two jet configurations, confined and unconfined, so that the recirculation behavior can be determined. The fluidic oscillator is found to improve only at a low z/d. At large z/d (greater than 4 in this study), the fluidic oscillator adversely affects the heat transfer.

This investigation focuses on multi-jet impingement configurations for gas turbine geometries in which the objective is to understand the influence of the roughness elements (ribs) on a target surface to the heat transfer and flow field. Existing studies in literature show the implementation of roughness elements for impingement configurations prove to increase heat transfer by 10–30%. Three different surface configurations are chosen for this multi-jet array impingement study: smooth surface (no ribs), small perpendicularly oriented ribs, and large perpendicularly oriented ribs. These roughness elements are non-continuous, broken rib turbulators which are square in cross section and oriented orthogonally to the mean flow direction within the cross flow duct. The roughness elements are oriented perpendicular to the mean flow direction. For each of the ribs tested, the two blockages tested, based on rib-to-channel height, were 20.83% and 41.67%. The jet impingement arrays are of an inline configuration. The Reynolds numbers tested, based on jet diameter, include 4,600, 13,300, 20,600, 30,200. The x/D (streamwise direction), y/D (spanwise direction), z/D (channel height direction) for the impingement array considered are 5 and 10, 8, and 3, respectively. A temperature sensitive paint technique was used to measure the heat transfer at the target surface, in which the local temperature was measured to estimate area averaged heat transfer coefficient (HTC), row averaged HTC, and stagnation region HTC. The spent air is made to exit from one direction only, thus generating a maximum cross flow situation. Keeping the jet diameter fixed at 5.1 mm, the pitch in the streamwise direction is doubled (x/D = 10) to study the effect of reducing coolant flow on the Nusselt Number distribution. Direct comparisons for heat transfer augmentation were done for all test nodes, including baseline flat/smooth plate cases. From the local heat transfer distributions of the different array patterns of the roughness elements, this study aims to determine the effect of including these elements on the target surface by the increases seen in heat transfer compared to a flat/smooth target plate.

El diagnóstico del dolor de cabeza en mujeres embarazadas representa un reto en la práctica clínica diaria. Si bien esta condición fisiológica se ha descrito como un factor de riesgo al momento de considerar etiologías secundarias, es adecuado plantear la utilidad de los criterios ICHD 3 como herramienta útil para diferenciar etiologías primarias de no primarias; esto especialmente cuando las banderas rojas tradicionales están ausentes.