Rheometric study of chitosan/activated carbon composite hydrogels for medical applications using an experimental design

Composite chitosan/activated carbon hydrogels were prepared with the vapor‐induced phase separation process. A rheometric study was performed with a factorial fractional design to determine the formulation and process parameters significantly influencing the mechanical properties of the gels. The results revealed that three factors played a key role in the storage modulus of the gels. According to the model, these factors could be classified with respect to their relative influence on the storage modulus in the following descending order: chitosan concentration > gel time of exposure to ammonia vapors > temperature of the reactor. Increasing these parameters led to an increase in the physical crosslinking density within the matrices and resulted in a reinforcement of the mechanical properties of the hydrogels. Two interactions were also shown to be significant and promoted the formation of supplementary junction zones within the matrix: the first one corresponded to the interaction between the chitosan concentration and the exposure time to ammonia vapors, and the second one concerned the interaction between the chitosan concentration and the temperature of the reactor. A second‐order model was obtained from statistical analysis. Because of the determination coefficient (89.4%) and the P value related to the lack of adjustment of the model (0.043), which was associated with a 95% confidence level, this model could be considered to be of good quality. Three gels were used to validate the model, and good accuracy was obtained. The maximum elastic modulus was obtained with the highest chitosan concentration [4% (w/v)], the highest temperature in the gelation chamber (50°C), and the longest time of exposure to ammonia vapors (24 h). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Hepatoprotection by palm tocotrienol‐rich fraction

Tocotrienols, a group of important phytonutrients of palm oil, have been shown to possess antioxidant, anticancer, neuroprotectory, and anti‐inflammatory activities. In this study, our objective was to examine the protective effects of tocotrienol‐rich fraction (TRF) from palm oil on chronic carbon tetrachloride (CCl₄)‐induced hepatotoxicity in rats. Animals were subjected to vehicle only (control), CCl₄ only, CCl₄ + 100 mg/kg silymarin (silymarin), CCl₄ + 25 mg/kg TRF (TRF‐25) and CCl₄ + 50 mg/kg TRF (TRF‐50) treatments for a period of 8 wks. Results showed that daily oral administration of TRF‐25, TRF‐50, and silymarin prevented the elevation of serum glutamate oxalate transaminase (sGOT) and glutamate pyruvate transaminase (sGPT), liver thiobarbituric acid reactive substances (TBARS), triglycerides and total cholesterol levels, as well as enhancing the liver catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) levels in rats with hepatotoxicity. At 50 mg/kg, the hepatoprotection of TRF was as good as or better than silymarin (100 mg/kg) in normalization of oxidative stress parameters in liver injury rats. These results suggest that TRF exerts effective protection against chronic CCl₄‐induced hepatic injury in rats, and its mechanism of action could be related to reducing oxidative stress in the liver tissue.     

Commercial Runner peanut cultivars in the USA: Fatty acid composition

Though peanuts are classified as a high‐fat food, they possess good proportions of fatty acids deemed as heart healthy. The fatty acid compositions of Runner peanuts were determined for commercially grown cultivars over two recent crop years. GC‐FID analyses revealed that the fatty acid levels for Runner peanuts were significantly (p <0.05) different among the normal, mid‐, and high‐oleic peanuts investigated. Oleic acid‐to‐linoleic acid (O/L) ratios were found to be 1.93 ± 0.30, 5.25 ± 1.12, and 16.9 ± 5.20 for normal, mid‐, and high‐oleic peanut lipids, respectively. Tamrun OL01 possessed a fatty acid profile characteristic of a mid‐oleic cultivar. From the sample set (n = 151), mean % weights for oleic acid and linoleic acid were 52.09 ± 2.84 and 27.38 ± 2.60 in normal, 69.33 ± 3.18 and 13.66 ± 2.35 in mid‐oleic, and 78.45 ± 2.05 and 5.11 ± 1.67 in high‐oleic peanuts, respectively. Cluster analysis segregated cultivars based on fatty acids into normal, mid‐, and high‐oleic groups. Factorial analysis revealed that cultivar effects were significant (p <0.01) for all fatty acids, except for lignoceric acid. Cultivar effects were also highly significant (p <0.001) for O/L, IV, unsaturated/saturated fatty acid (U/S) ratio, and % saturation. Significant crop year effects were shown for palmitic, oleic, arachidic, gondoic, and lignoceric acids, as well as U/S ratio and % saturation. Healthy unsaturated fats accounted for ?80% in all crop years and cultivars.