Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions

A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip.

Association between the epithelial cadherin -160C/A gene polymorphism and diffuse gastric cancer risk: a meta-analysis

Several previous studies have investigated whether the -160C/A epithelial cadherin promoter polymorphism confers an increased risk of diffuse gastric cancer (DGC), but conflicting results have been reported. To explore further the association of this polymorphism with DGC susceptibility, we performed an extensive search of relevant studies and conducted a meta-analysis to obtain a more precise estimate. We conducted a systematic literature search using the databases EMBASE, PubMed, and Web of Knowledge for reports published before August 2012 that met certain criteria. Information was carefully and independently extracted from all eligible publications by 2 of the authors. Twelve distinct data sets from 10 case-control studies were analyzed. They included 1115 cases of DGC and 2965 controls. Although none of the genotypes was associated with DGC risk, a slight trend of increased risk was found among A allele carriers [odds ratio (OR) = 1.237, 95% confidence interval (95%CI), 0.940-1.627], CA heterozygotes (OR = 1.229, 95%CI = 0.938-1.610), and AA homozygotes (OR = 1.146, 95%CI = 0.684-1.918). However, when the cases were stratified by ethnicity, a diverging trend occurred in AA homozygotes between the Asian group (OR = 0.710, 95%CI = 0.328-1.536) and its Caucasian counterpart (OR = 1.434, 95%CI = 0.657-3.131). Taken together, the summarized analyses of these case-control studies demonstrated that the -160A of the epithelial cadherin gene exhibited no significant association with susceptibility for DGC; however, the results suggested that it is a potential genetic risk factor in both Asians and Caucasians. Additional large-scale, well-designed studies are necessary to confirm whether AA homozygosity is a protective factor in Asians.

Transcutaneous ultrasound of the cervical esophagus in patients with esophageal carcinoma

Transcutaneous ultrasound of the cervical esophagus was performed in 46 patients with esophageal carcinoma and in 35 controls. The former had 24 upper segmental lesions and 22 lower segmental lesions. The level of the sternoclavicular joint was used to divide the esophagus into the upper segmental (USE) and lower segmental esophagus (LSE). The anterior esophageal wall thickness and luminal dimensions were measured before and immediately after phonation. The mean wall thickness in the controls was 1.8 mm before phonation and 2.1 mm after phonation, with a significant difference (t test, P < 0.05). The mean wall thickness in the USE carcinoma group was 4.3 mm and 4.4 mm before and after phonation respectively. There was a significant difference between the controls and USE carcinoma groups (t test, P < 0.05). The cross sectional area, which was calculated as the product of anterio-posterior and lateral diameters, averaged 28 mm2 before phonation in the controls and increased to 44 mm2 after phonation (t test, P < 0.05). The mean cross sectional area in the USE carcinoma group was significantly smaller before phonation than that in the controls (t test, P < 0.05) and showed little change after phonation. No significant difference was found between LSE carcinoma and control groups. Transcutaneous ultrasound appears to be a promising non-invasive method of investigation for cervical esophageal carcinoma.

[Study on surgical resection length of esophageal carcinoma: an analysis of 2325 cases of the resected samples with esophageal carcinoma]

The paper studied the relationship between the resected length above and below the esophageal carcinoma and positive rate of the residual carcinoma in the resected rims. The positive rates of the carcinoma were 65.0%, 17.2%, 12.3%, 10.6%, 6.7%, 5.8%, 4.0%, 3.1%, 2.0%, 0.9% and 0% respectively while the length of the resected esophagus above and below the carcinoma was 1-10 cm and 10 cm respectively. The results shown that it would be the best for all patients with esophaged carcinoma to resect esophagus more than 10 cm in length above and below the carcinoma respectively.

Intussusception anastomosis of the esophagus: a new method of anastomosis after resection of esophageal or cardiac carcinoma

A new method of anastomosis after resection of esophageal or cardiac carcinoma was carried out in 141 patients in Anyang Cancer Hospital from February 1983 to September 1985. After resection of the tumor, the proximal end of the esophagus was intussuscepted into the stomach lumen and extroversion sutures were applied on the esophageal mucosa to prevent bleeding and stenosis. In this series, the operative mortality was 0.7% (1/141) and no anastomotic leakage was found. We consider that this modified operative procedure is fairly easy, simple, and beneficial in reducing surgical complications.

[Invagination anastomosis of the esophagus--a new method of anastomosing after resection of esophageal or cardial carcinoma]

A new method of anastomosis after resection of esophageal or cardial carcinoma was carried out in 141 patients in our hospital from Feb. 1983 to Sept. 1985. After resection of the tumor, the proximal end of esophagus was invaginated into the stomach lumen and a tight suture was applied between the outer wall of esophagus and stomach. Extroversion suture of the mucosa in the esophageal end, being free in the stomach lumen, was made to prevent bleeding and stenosis. The operative mortality was 0.7% (1/141) and no anastomotic leak was found. Our experiences indicate that this operative procedure is easy, simple and obviously reduces the complication in the anastomotic region.