OPTIMIZATION OF A PROCESS FOR DISCOLORATION OF LOW-GRADE SYRUP

L'amélioration de la couleur du sirop industriel de qualité inférieure, sur le charbon actif, a été optimisée à l'aide d'une conception composite centrale et d'une méthodologie de surface de réponse. Cette étude vérifie l'effet de trois paramètres expérimentaux : masse d'adsorbant (charbon actif), temps de contact adsorbat-adsorbant (sirop - charbon actif), rapport de masses des farines constituant le gâteau de filtration (m w /m b ) , et leurs interactions sur la réponse : ICUMSA Color. L'exploitation du modèle établi dans l'espace des variables a permis de définir des conditions économiques optimales d'obtention de sirop de classe claire selon la Commission Internationale pour les Méthodes Uniformes d'Analyse du Sucre (ICUMSA)

Advanced statistical optimization of parameters of synthesis process of oxygenated carbonated apatite

International audienceThe synthesis process of oxygenated carbonated apatite was optimized by an advanced statistical planning of experiments. Full factorial design of 24 experiments was used to find the effects of five principal parameters: pH of the reaction medium, atomic ratio Ca/P of the reagents, concentration of the calcium solution (Ca2+), temperature of the reaction medium (T) and duration of the reaction (D), with fixing the H2O2 composition at 30% and stirring to 600 turns/min. Studied responses were the atomic ratio Ca/P, % O2, % O2 2− and % CO3 2−. Optimum synthesis parameters were found to be pH = 7.38, Ca/P = 1.647, [Ca2+] = 0.636 M, T = 40°C and D = 1 h. The prediction responses were Ca/P = 1.575, % O2 = 0.76, % O2 2− = 0.50 and % CO3 2−= 1.84. The actual experimental results were in agreement with the prediction

Synthesis, characterization and thermal behaviour of a Phosphocalcic Oxygenated Apatite

A new route for preparing an antiseptic biomaterial has been described. An oxygenated apatite-based calcium phosphate powder that had a Ca/P ratio of 1.55 was synthesized from calcium nitrate and phosphoric acid in oxygenated water via a precipitation method. The X-ray diffraction and FTIR analysis of the as-dried powder reveals that the apatite is poorly crystalline and is converted into a biphasic calcium phosphate (HAP/beta TCP) when calcined at a temperature higher than 600°C. The chemical analysis of oxygenated species shows the disappearance of these species at 400°C

CO2 is the contrast media to choose in patients with initial Chronic Kidney Disease undergoing endovascular aneurysm repair to prevent further renal function deterioration

Objective: Even low quantities of iodine contrast media (ICM) could be responsible for exacerbation of a chronic kidney disease (CKD). Aim of this study was to determine whether it is more reasonable to perform endovascular aneurysm repair (EVAR) procedures in patients with initial CKD using CO2 rather than ICM to prevent further kidney deterioration. Methods: A retrospective analysis was performed at our institution to identify patients with preoperative CKD at initial stage (class G3a-G3b according to KDOQI-KDIGO classification) who underwent either CO2-EVAR or ICM-EVAR. Primary endpoint was renal function evaluation; secondary endpoints were technical success, perioperative complications, hospital stay, and reinterventions and overall mortality at follow-up. Results: Both CO2-EVAR and ICM-EVAR groups were composed of 21 patients. There were no differences in demographics, anatomy, and comorbidities, apart from worse ASA score in CO2-EVAR group (100% vs 57.1%, p =.001). Preoperative serum creatinine and glomerular filtration rates (GFR) were comparable (1.73 vs 1.6 mg/dl, p =.082 and 39.71 vs 43.04 mL/min/1.73 m2, p =.935). At follow-up (16.7 ± 18.1 months), CO2-EVAR was not associated with significant changes in creatinine and GFR, whereas ICM-EVAR determined a significant increase in creatinine (1.6 mg/dl vs 1.91 mg/dl, p =.04) and decrease in GFR values (43 vs 37.9 mL/min/1.73 m2, p =.04), determining the need for dialysis in one patient. Conclusions: ICM seems to be a determining factor in worsening renal function; therefore, an effort should be made to standardize the use of CO2 as the contrast medium of choice in patients with initial renal insufficiency undergoing EVAR