The spinning disc reactor (SDR) uses surface rotation to produce thin film flow with improved mixing and reduced residence times in chemical processing applications. Solvent-antisolvent precipitation is one such process that can benefit from these properties. This study investigates the film hydrodynamics and precipitation of starch nanoparticles by contacting starch dissolved in sodium hydroxide with ethanol as the antisolvent. One objective of this study is to understand how interactions of the disc surface topography (grooved and smooth) with other parameters such as liquid flowrate, antisolvent to solvent flow ratio and disc speed impact the mixing and precipitation processes. Results indicate that an increase in flow rate and rotational speed leads to smaller nano-particles and narrower size distributions, which is attributed to increased shear and instabilities within the liquid film. It was also observed that an increased antisolvent to solvent ratio caused a reduction in particle size, as increased antisolvent generated higher supersaturation. Results showed that although particle size was not significantly influenced by the disc texture, the size distribution was narrower and higher yields were obtained with the grooved disc surface. The grooved disc therefore offers the opportunity for higher throughput in the solvent-antisolvent precipitation of starch particles with better product quality.
Our aim was to investigate the relation between fetal distress and oxidative stress. Fetal distress was associated with increased concentration of superoxide in the fetal blood and with significant increase of the level of H2O2 in both maternal and fetal blood. The activity of superoxide dismutase was increased roughly sixfold (p < 0.01) in the maternal [7330 ± 2240 U/g of hemoglobin in controls (C) and 36811 ± 16862 U/g in fetal distress (FD)] and fetal blood (C: 5930 ± 2641 U/g; FD: 41912 ± 17133 U/g). In contrast, fetal distress was related to a considerable decrease of catalase activity in both maternal (C: 26011 ± 8811 U/g; FD: 7212 ± 1270 U/g) and fetal blood (C: 37194 ± 9191 U/g; FD: 6173 ± 1965 U/g). From this we concluded that in fetal distress, the maternal and fetal bloods are exposed to superoxide- and H2O2-mediated oxidative stress, which could be initiated by hypoxic conditions in the fetal blood and placenta. A tremendous increase/decrease of the activities of superoxide dismutase/catalase in the blood of women bearing a distressed fetus in comparison to healthy subjects implies that the assessment of superoxide dismutase/catalase activity could be of use for establishing a timely and accurate ante- or intrapartum diagnosis of fetal distress.
Solid-liquid micro-fluidised beds (FBs), i.e. fluidisation of micro-particles in sub-centimetre beds, hold promise of applications in the microfluidics and micro-process technology context. This is mainly due to fluidised particles providing enhancement of mixing, mass and heat transfer under the low Reynolds number flows that dominate in micro-devices. Albeit there are quite a few studies of solid-liquid micro-fluidised beds, we are presenting the first study of a micro-circulating fluidised bed. The present experimental research was performed in a micro-circulating fluidised bed which was made by micro-machining channels of 1mm 2 cross section in Perspex. PMMA and soda lime glass micro-particles were used as the fluidised particles and tap water as the fluidising liquid to study flow regime transition for this micro-circulating fluidised bed. The results are in line with macroscopic observation that the critical transition velocity from fluidization to circulating regime is very dependent on solid inventory but once the inventory is high enough it is approximately equal to the particle terminal velocity. However, the transitional velocity is a weakly dependent on wall effect and surface forces confirming the importance of these two properties in a micro-fluidised bed systems. Similarly the transitional velocity to transporting regime is a strong function of surface forces. Finally, combining these results with our previous result on conventional fluidization indicated that map of solid-liquid fluidisation in a micro-circulating fluidised bed system is constructed showing conventional fluidisation, circulating fluidisation and a transport regime.
Monosodium glutamate (MSG), the sodium salt of glutamate, is commonly used as a flavor enhancer in modern nutrition. Recent studies have shown the existence of glutamate receptors on lymphocytes, thymocytes and thymic stromal cells. In this study, we evaluated the in vitro effect of different MSG concentrations on rat thymocyte apoptosis and expression of two apoptosis-related proteins, Bcl-2 and Bax. Rat thymocytes, obtained from male Wistar rats, were exposed to increasing concentrations of MSG (ranging from 1 mM to 100 mM) for 24 h. Apoptosis was detected using the Annexin V-FITC/PI apoptosis detection kit and cells were analyzed using a flow cytometer. Expression of Bcl-2 and Bax proteins were determined with flow cytometry using respective monoclonal antibodies. Exposure to MSG resulted in a dose-dependent decrease in cell survival (as determined by trypan blue exclusion method). Annexin V-FITC/PI also confirmed that MSG increased, in a dose-dependent manner, apoptotic cell death in rat thymocyte cultures. MSG treatment induced downregulation of Bcl-2 protein, while Bax protein levels were not significantly changed. Our data showed that MSG significantly modulates thymocyte apoptosis rate in cultures. The temporal profile of Bcl-2 and Bax expression after MSG treatment suggests that downregulation of Bcl-2 protein and the resulting change of Bcl-2/Bax protein ratio may be an important event in thymocyte apoptosis triggered by MSG.
<p><strong>Aim <br /></strong>To investigate the age (in months) at which motor skills are developed in children with Down syndrome (DS), and compare it to the age of the development of the same skills in both, children with typical development (TD), and children with DS reported by four other studies. <br /><strong>Methods<br /></strong> Sixteen children (7 girls and 9 boys) were monthly assessed for the development of nineteen motor skills between 2008 and 2011. The mean ages when the skills were accomplished were presented using descriptive statistics. Independent T-samples test (significance &lt; 0.05) was used to compare the mean developmental ages from our study with those seen in children with TD (Comparison 1) and also in children with DS reported by four other authors (Comparison 2a-2d). <br /><strong>Results</strong> <br />Children with DS developed at a significantly slower pace compared to children with TD (p=0.005). Generally, delay and variance of developmental age in children with DS increased chronologically with the complexity of the skills. No significant difference was found between developmental age in children from the present study and children with DS from other studies. <strong>Conclusion</strong> <br />The rate of attainment of motor skills is delayed in children with DS in comparison to children with TD, however, the developmental sequence is the same. The delayed development is more prominent in more complex skills.</p>
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