ABSTRACT
Heat transfer takes place in every aspect of our daily life. Many situations, such as energy conversion plants, heating devices, and cooling systems, focus on heat transfer. One of the subjects in heat transfer is the boundary layer of the laminar flow problem. Well-known exploratory algorithms are used to solve for the flow on a flat plate in this study. The algorithms used are genetic algorithm (GA), particle swarm optimization (PSO), simulated annealing (SA), ant colony optimization for continuous domains (ACOR), artificial bee colony (ABC), and firefly algorithm (FA). The three properties, the layer thickness of the laminar boundary, heat flux, and the distance of the leading edge, are optimized. Each property is determined in three conditions; minimum, maximum, and target. The results showed that PSO, SA, ABC, and FA algorithms were more suitable than GA and ACOR algorithms. It has also been determined that the processing times are long in the FA and SA algorithms. The findings show that heuristic algorithms can find global results or results close to global results in heat transfer problems.
ABSTRACT
BACKGROUND/AIMS: The present study was conducted to determine if obstructive jaundice promotes bacterial translocation and to evaluate the changes in hepatic histopathology in patients with benign biliary obstruction. METHODOLOGY: Between January 1996 and January 1998, 19 patients treated for benign biliary obstruction were studied. Fourteen patients with symptomatic cholelithiasis were taken as the control group. Patient characteristics, preoperative and post-operative laboratory tests with an interval of 7 days were recorded. In all patients, bile and mesenteric lymph nodes samples were taken for bacterial growth and histopathologic changes were studied on the liver excised during surgery. RESULTS: In the control group, bacterial growth was observed in the bile and mesenteric lymph nodes cultures in one (7.1%) and two patients (14.3%), respectively. In the study group, 8 patients (42%) had positive bile cultures and 12 patients (63.2%) had positive mesenteric lymph nodes cultures, respectively. Histopathologic examination of the liver revealed significant increase in the rate of periductal and portal fibrosis in the jaundiced patients, compared with control group (p < 0.001). Postoperative complications in the study group were wound infection (3 cases), renal failure (2 cases), ARDS (1 cases) and intraabdominal abscess (1 cases). In the control group, one patient had wound infection and one had atelectasis. Two patients with jaundice died of multiple organ failure and respiratory failure. In long-term follow-up (mean 17 months), when sclerosing cholangitis and secondary biliary cirrhosis developed in one patient each in the study group, no long-term complication occurred in the control group. CONCLUSIONS: Our clinical results demonstrate that extrahepatic biliary obstruction promotes bacterial translocation and this process is an important cause of morbidity and mortality in patients with jaundice. Also, obstructive jaundice subsequently leads to significant functional and morphological damage in the liver.
