BackgroundCraniofacial resection (CFR) has been regarded as a standard treatment for various tumors involving the anterior skull base. The purpose of this study was to evaluate the results of CFR for the patients with anterior skull base malignancies in our hospital.MethodsWe retrospectively analyzed 17 patients with anterior skull base malignancies treated with CFR between 2001 and 2012. Mean follow-up duration was 41 months (range, 2-103 months).ResultsIntracranial involvement was found in 11 patients (65%) and orbital extension in 6 patients (35%). Classical bifrontal craniotomy was combined with endoscopic endonasal approach in 14 patients and external approach in 3 patients. Vascularized flap was used for reconstruction of the anterior fossa floor in 16 patients (94%). The most common pathological type was squamous cell carcinoma (6 patients). Gross total resection was achieved in all cases. Postoperative complications developed in 4 patients (24%) and included local wound problem and brain abscess. One patient with liver cirrhosis died from unexpected varix bleeding after the operation. Although postoperative treatment, such as radiotherapy or chemotherapy, was performed in 14 patients, local recurrence was seen in 6 patients. The mean overall survival time after the operation was 69.0 months (95% confidence interval: 47.5-90.5 months) with a 1-, 2-, and 5-year survival rate of 82.3%, 76.5%, and 64.7%, respectively. Postoperative radiotherapy was found to be the powerful prognostic factor for favorable survival.ConclusionConsidering the higher local control rate and acceptable complication or mortality rate, CFR with adjuvant radiotherapy is a gold standard treatment option for malignant tumors involving anterior skull base, especially with extensive intracranial involvement.

A district heating system is an eco-friendly power generation facility with high energy efficiency. The boiler water wall tube used in the district heating system is exposed to extremely harsh conditions, and unexpected fractures often occur during operation. In this study, a corrosion failure analysis of the boiler water wall tube was performed to elucidate the failure mechanisms. The study revealed that overheating by flames was the cause of the failure of the boiler water wall tube. With an increase in temperature in a localized region the microstructure not only changed from ferrite/pearlite to martensite/bainite, which made it more susceptible to brittleness, but it also developed tensile residual stresses in the water-facing side by generating cavities or microcracks along the grain boundaries inside the tube. High-temperature hydrogen embrittlement combined with stress corrosion cracking initiated many microcracks inside the tube and created an intergranular fracture.

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