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.

Interaction of caveolin-1 with ATG12-ATG5 system suppresses autophagy in lung epithelial cells

Autophagy plays a pivotal role in cellular homeostasis and adaptation to adverse environments, although the regulation of this process remains incompletely understood. We have recently observed that caveolin-1 (Cav-1), a major constituent of lipid rafts on plasma membrane, can regulate autophagy in cigarette smoking-induced injury of lung epithelium, although the underlying molecular mechanisms remain incompletely understood. In the present study we found that Cav-1 interacted with and regulated the expression of ATG12-ATG5, an ubiquitin-like conjugation system crucial for autophagosome formation, in lung epithelial Beas-2B cells. Deletion of Cav-1 increased basal and starvation-induced levels of ATG12-ATG5 and autophagy. Biochemical analyses revealed that Cav-1 interacted with ATG5, ATG12, and their active complex ATG12-ATG5. Overexpression of ATG5 or ATG12 increased their interactions with Cav-1, the formation of ATG12-ATG5 conjugate, and the subsequent basal levels of autophagy but resulted in decreased interactions between Cav-1 and another molecule. Knockdown of ATG12 enhanced the ATG5-Cav-1 interaction. Mutation of the Cav-1 binding motif on ATG12 disrupted their interaction and further augmented autophagy. Cav-1 also regulated the expression of ATG16L, another autophagy protein associating with the ATG12-ATG5 conjugate during autophagosome formation. Altogether these studies clearly demonstrate that Cav-1 competitively interacts with the ATG12-ATG5 system to suppress the formation and function of the latter in lung epithelial cells, thereby providing new insights into the molecular mechanisms by which Cav-1 regulates autophagy and suggesting the important function of Cav-1 in certain lung diseases via regulation of autophagy homeostasis.

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.

Caveolin-1 inhibits expression of antioxidant enzymes through direct interaction with nuclear erythroid 2 p45-related factor-2 (Nrf2)

The Nrf2 (nuclear erythroid 2 p45-related factor-2) signaling pathway is known to play a pivotal role in a variety of oxidative stress-related human disorders. It has been reported recently that the plasma membrane resident protein caveolin-1 (Cav-1) can regulate expression of certain antioxidant enzymes and involves in the pathogenesis of oxidative lung injury, but the detailed molecular mechanisms remain incompletely understood. Here, we demonstrated that Cav-1 inhibited the expression of antioxidant enzymes through direct interaction with Nrf2 and subsequent suppression of its transcriptional activity in lung epithelial Beas-2B cells. Cav-1 deficiency cells exhibited higher levels of antioxidant enzymes and were more resistant to oxidative stress induced cytotoxicity, whereas overexpression of Cav-1 suppressed the induction of these enzymes and further augmented the oxidative cell death. Cav-1 constitutively interacted with Nrf2 in both cytosol and nucleus. Stimulation of 4-hydroxynonenol increased the Cav-1-Nrf2 interaction in cytosol but disrupted their association in the nucleus. Knockdown of Cav-1 also disassociated the interaction between Nrf2 and its cytoplasmic inhibitor Keap1 (Kelch-like ECH-associated protein 1) and increased the Nrf2 transcription activity. Mutation of the resembling Cav-1 binding motif on Nrf2 effectively attenuated their interaction, which exhibited higher transcription activity and induced higher levels of antioxidant enzymes relative to the wild-type control. Altogether, these studies clearly demonstrate that Cav-1 inhibits cellular antioxidant capacity through direct interaction with Nrf2 and subsequent suppression of its activity, thereby implicating in certain oxidative stress-related human pathologies.

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.