No abstract

Transport properties and solvent induced-crystallization phenomena (SINC) in poly(ethylene terephthalate) (PET) and PET clay nanocomposites (nano-PET), prepared by melt intercalation, with a clay content of 5 % w/w, have been investigated. Films were obtained by hot pressing and characterized before and after the sorption in several solvents: toluene, benzene and chlorobenzene. Results of nonisothermal crystallization dynamics showed that the cold crystallization temperature, and the percent of crystallinity of Nano-PET films are higher than those of pure PET. The sorption of all of the used solvents is accompanied by a large-scale structural rearrangement, with leads to the induced crystallization of the original amorphous state. That solvent induced crystallization caused an increasing of up to four times the percent of crystallinity.

Background: Bacterial translocation (BT) from the gut can develop and persist after short periods of hemorrhagic shock secondary to traumatic injuries. Erythroopoietin (EPO) exerts hemodynamic and anti-inflammatory effects in addition to its erythropoietic effect. We tested the hypothesis that EPO given at the time of acute resuscitation with normal saline (NS), Ringer's lactate (RL) or 7.5% hypertonic saline (7.5%HTS) will limit shock-induced mucosal injury and BT. Methods: Rats were hemorrhaged 30 mL/kg over 10 minutes via arterial catheter for 50 minutes, then randomized to 1 of 6 resuscitation groups (n = 5/group): NS, NS+EPO, RL, RL+EPO, 7.5%HTS and 7.5%HTS+EPO. Intravenous EPO (1000 U/kg) was given at the start of NS or RL (3 times the volume of shed blood) and 4 mL/kg of 7.5%HTS+1 volume of RL resuscitation. Postresuscitation gut function was evaluated using agar cultures of mesenteric lymph nodes and portal vein plasma lipopolysaccharide, IL-6 and TNF-α levels. Three of 5 rats per group underwent light microscopic examination using semi-thin plastic sections of the distal ileum and fluorescein isothiocyanate dextran 4000 used to assess the distal ileum mucosal permeability to macromolecules. Results: Two hours postshock and resuscitation, BT to mesenteric lymph nodes decreased in the NS+EPO versus the NS group (299 ± 104 v. 1050 ± 105 CFU/gm, p < 0.05); the addition of EPO to the RL or 7.5%HTS had no effect. Comparing different solutions, there was a significant increase in BT in the NS group versus the RL+EPO, 7.5%HTS+EPO and 7.5%HTS groups (1050 ± 105 v. 357 ± 134, 462 ± 129, 428 ± 106 CFU/gm, respectively; p < 0.05). There were no significant differences in terminal ileum permeability between groups, but there was a noticeable trend in decreasing terminal ileum permeability in the EPO-treated groups: NS versus NS+EPO (18.0 ± 9.5 v. 12.9 ± 6.3 µg/mL, p = 0.84), RL versus RL+EPO (17.7 ± 5.9 v. 8.4 ± 2.7 µg/mL, p = 0.22) and 7.5%HTS versus 7.5%HTS+EPO (11.4 ± 6.4 v. 6.5 ± 2.9 µg/mL, p = 0.69). There was no significant morphological evidence of mucosal injuries and no cytokine differences between groups and within groups. Conclusion: Preliminary data from an uncontrolled mean arterial pressure hemorrhagic shock rat model revealed that BT is an early event occurring within 2 hours of injury and resuscitation before any evidence of histological injury. Erythroopoietin with NS significantly decreased BT to the portal vein as compared with NS alone, but not with RL and 7.5%HTS.Analgesia in the management of pediatric trauma in the resuscitative phase: the role of the trauma centre.