Toughening of Low-Alloy Steel by Ultrafine-Grained Structure (Development of Fracture Control from Microstructure Design)

Microstructural design for improving the strength–toughness balance was studied in low-alloy steel. Medium-carbon steel bars with microstructures of two types such as an ultrafine elongated grain (UFEG) structure and an ultrafine equiaxed grain (UFG) structure were fabricated by multi-pass warm caliber rolling and subsequent annealing. Conventionally, quenched and tempered steel with a martensitic structure and low-carbon steel with a ferrite–pearlite structure were also prepared. The tensile and three-point bending tests were conducted for all samples. In particular, the fracture behavior after the bending test was observed in detail and investigated, including the effect of microstructure features. As a result, the strength–toughness balance of the UFEG steel was excellent compared with that of all other steels. The present results provide useful guidelines for designing microstructure to improve the strength–toughness balance in metallic materials

Monitoring perioperative serum albumin can identify anastomotic leakage in colorectal cancer patients with curative intent

SummaryBackgroundPreoperative hypoalbuminemia is a well-known risk factor for anastomotic leakage after colorectal surgery, but the association between perioperative albumin level and anastomotic leakage has not been fully investigated in curative colorectal cancer (CRC) patients.MethodsIn total, 200 CRC patients (Stage I–III) undergoing curative laparoscopic surgery between January 2004 and December 2013 were enrolled in this study. We collected data on surgical factors, perioperative levels of serum albumin and inflammatory markers, and perioperative factors affecting hypoalbuminemia from 196 CRC patients to assess the relation to anastomotic leakage.ResultsAnastomotic leakage occurred in 11 cases (5.6%) and the frequency was higher in rectal cancer patients (p = 0.0044). There was no significant difference of preoperative serum albumin level between the anastomotic leakage group (AL) and the nonanastomotic leakage group (NAL). Postoperative serum albumin levels in AL were significantly lower than in NAL [postoperative day (POD) 0, p = 0.0004; POD1, p = 0.0001; POD3, p = 0.0004; and POD7, p = 0.0021]. On multivariate analysis, lower average level of serum albumin on POD1 and POD3 {odds ratio (OR) [95% confidence interval (CI)] = 7.53 (1.60–55.80), p = 0.0095}, higher average level of serum white blood cells on POD1 and POD3 [OR (95% CI) = 7.24 (1.40–59.25), p = 0.0165], and surgery for rectal cancer [OR (95% CI) = 15.18 (3.26–93.99), p = 0.0004] were independent risk factors for anastomotic leakage.ConclusionLower early postoperative serum albumin levels are a potentially valuable indicator of anastomotic leakage in CRC patients undergoing curative surgery