Microstructure Evolution and the Resulted Influence on Localized Corrosion in Al-Zn-Mg-Cu Alloy during Non-Isothermal Ageing.

A non-isothermal ageing process was proposed for an Al-Zn-Mg-Cu alloy aiming to accommodate the slow heating/cooling procedure during the ageing of large components. The evolution of microstructure and microchemistry was analyzed by using transmission electron microscopy, high-angle annular dark field imaging, and energy dispersive spectrometry. The age-hardening of the alloy was examined to evaluate the strengthening behavior during the non-isothermal process. The corrosion behavior was investigated via observing the specimens immersed in EXCO solution (solution for Exfoliation Corrosion Susceptibility test in 2xxx and 7xxx series aluminum alloys, referring ASTM G34-01). Secondary precipitation was observed during the cooling stage, leading to increased precipitate number density. The distribution of grain boundary precipitates transits from discontinuous to continuous at the cooling stage, due to the secondary precipitation’s linking-up effect. The solutes’ enrichment on grain boundary precipitates and the depletion in precipitate-free zones develops during the heating procedure, but remains invariable during the cooling procedure. The corrosion in NIA (Non-isothermal Ageing) treated specimens initiates from pitting and then transits to intergranular corrosion and exfoliation corrosion. The transition from pitting to intergranular corrosion is very slow for specimens heated to 190 °C, but accelerates slightly as the cooling procedure proceeds. The transition to exfoliation corrosion is observed to be quite slow in all specimens in non-isothermal aged to over-aged condition, suggesting a corrosion resistance comparable to that of RRA condition.

Incidence of port-site metastasis after undergoing robotic surgery for biliary malignancies.

AIM: To investigate the incidence of clinically detected port-site metastasis (PSM) in patients who underwent robotic surgery for biliary malignancies. METHODS: Using a prospective database, the patients undergoing fully robotic surgery for biliary malignancies between January 2009 and January 2011 were included. Records of patients with confirmed malignancy were reviewed for clinicopathological data and information about PSM. RESULTS: Sixty-four patients with biliary tract cancers underwent robotic surgery, and sixty patients met the inclusion criteria. The median age was 67 year (range: 40-85 year). During a median 15-mo follow-up period, two female patients were detected solitary PSM after robotic surgery. The incidence of PSM was 3.3%. Patient 1 underwent robotic anatomatic left hemihepatectomy and extraction of biliary tumor thrombi for an Klatskin tumor. She had a subcutaneous mass located at the right lateral abdominal wall near a trocar scar. Patient 2 underwent robotic pancreaticoduodenectomy for distal biliary cancer. She had two metachronous subcutaneous mass situated at the right lateral abdominal wall under a same trocar scar at 7 and 26 mo. The pathology of the excised PSM masses confirmed metastatic biliary adenocarcinoma. CONCLUSION: The incidence of PSMs after robotic surgery for biliary malignancies is relatively low, and biliary cancer can be an indication of robotic surgery.

XRCC1 Arg399Gln gene polymorphism and hepatocellular carcinoma risk in the Chinese Han population: a meta-analysis.

PURPOSE: Numerous studies have evaluated the association between XRCC1 Arg399Gln gene polymorphism and hepatocellular carcinoma risk in the Chinese Han population. However, the results have been inconsistent. We therefore here examined whether the XRCC1 Arg399Gln gene polymorphism confers hepatocellular carcinoma risk by conducting a meta-analysis. METHODS: PubMed, Google scholar and China National Knowledge Infrastructure databases were searched for eligible articles in English and Chinese that were published before April 2012. RESULTS: 6 studies involving 1,246 patients with hepatocellular carcinoma and 1,953 controls were included. The association between XRCC1 Arg399Gln gene polymorphism and hepatocellular carcinoma in the Chinese Han population was significant under GG vs AA (OR = 1.48, 95% CI = 1.13 to 1.94). Limiting the analysis to the studies with controls in the Hardy-Weinberg equilibrium, the results were persistent and robust. CONCLUSIONS: In the Chinese Han population, the XRCC1 Arg399Gln gene polymorphism is associated with an increased hepatocellular carcinoma risk.

Outcomes of pancreatoduodenectomy with robotic surgery versus open surgery.

BACKGROUND: Pancreatoduodenectomy (PD) for pancreatic cancer is very challenging to many surgeons. Information regarding the advantage of using the Da Vinci robotic system over conventional open surgery for PD is rare. Therefore, a comparison of the outcomes of PD performed using the Da Vinci robotic system with outcomes using open surgery was conducted. METHODS: Between January 2009 and December 2009 sixteen patients underwent PD, eight patients receiving robot-assisted surgery using the Da Vinci surgical robotic system (Group I) and eight being treated using conventional open surgery (Group II). RESULTS: There was no significant difference in radical resection (R0) rate between the two groups, 87.5% vs 100%, P = 0.05. The operative time in group I was longer than in group II, 718 ± 186 vs 420 ± 127 min, P = 0.011, while the surgical blood loss in group I was less than in group II, 153 ± 43 vs 210 ± 53 mL, P = 0.045. The length of bed time and hospital stay after surgery in group I were shorter than in group II, 27.5 ± 7.1 vs 96 ± 18.1 h, P = 0.000; 16.4 ± 4.1 vs 24.3 ± 7.1 days, P = 0.04, respectively). Complication rate of group I was lower than that of group II, 25% vs 75%, P = 0.05. CONCLUSION: It is feasible and safe to perform PD using the Da Vinci robot-assisted surgical system; patients recovered faster postoperatively with less blood loss during surgery.

Aqueous solution synthesis of CaF2 hollow microspheres via the ostwald ripening process at room temperature.

Nearly monodispersive CaF2 hollow microspheres were synthesized by a facile aqueous solution route from the mixed aqueous solutions of CaCl2, Na2WO4, and NaF at room temperature. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy, and N2 adsorption-desorption techniques. The CaF2 hollow microspheres have an average diameter of about 1.5 microm and a hollow interior of 0.5 microm. The shell is composed of numerous single-crystalline nanoparticles with diameter of about 20 nm. The morphologies and diameters of the CaF2 products are strongly dependent on the experimental parameters, such as the concentration of the aqueous NaF solution and the reaction temperature. The synthetic experiments indicate that the growth process of CaF2 hollow microspheres involves first the formation of CaWO4 solid microspheres and then the formation of CaF2 solid microspheres through the reaction between CaWO4 and F(-) ions controlled by the difference of the solubility product for CaWO4 and CaF2. Phenomenological elucidation based on TEM observations and XRD patterns of intermediate products at different precipitation stages indicates that the formation mechanism for the CaF2 hollow microspheres is related to the Ostwald ripening mechanism. N2 adsorption-desorption measurement shows that the CaF2 hollow microspheres possess a high Brunauer-Emmett-Teller surface area and porosity properties. The synthetic procedure is straightforward and represents a new example of the Ostwald ripening mechanism for the formation of inorganic hollow structures in an aqueous solution at room temperature.