Smoothing effect for spatially distributed renewable resources and its impact on power grid robustness.

In this paper, we show that spatial correlation of renewable energy outputs greatly influences the robustness of the power grids against large fluctuations of the effective power. First, we evaluate the spatial correlation among renewable energy outputs. We find that the spatial correlation of renewable energy outputs depends on the locations, while the influence of the spatial correlation of renewable energy outputs on power grids is not well known. Thus, second, by employing the topology of the power grid in eastern Japan, we analyze the robustness of the power grid with spatial correlation of renewable energy outputs. The analysis is performed by using a realistic differential-algebraic equations model. The results show that the spatial correlation of the energy resources strongly degrades the robustness of the power grid. Our results suggest that we should consider the spatial correlation of the renewable energy outputs when estimating the stability of power grids.

[A case report: multiple air embolism after the laryngopharyngoesophagectomy occurred by the cervical infection from postoperative fistula].

Systemic air embolism, a very rare clinical condition, has many causes. We report a case of multiple air embolisms following laryngopharyngoesophagectomy salvage surgery for hypopharyngeal residual cancer after concurrent chemoradiotherapy. Cervical infection arose from a fistula caused by postoperative suture failure in which the 56-year-old man suddenly lost consciousness and went into shock. A few days post operation, an air embolism happened and caused in the brain, pulmonary, myocardiac and cerebral infarction. The man died two months after initial occurrence. We suspect that air entered through the ruptured left internal jugular vein via infection due to aspiration at the injury site. Air embolisms are associated with different medical maneuvers, and it is necessary to recognize that they may become a serious perioperative complication.

Preoperative concurrent chemoradiotherapy versus pre- and postoperative radiotherapy for advanced hypopharyngeal carcinoma: a single-center study.

OBJECTIVE: The purpose of this study was to improve the survival and phonatory rates in patients with advanced hypopharyngeal carcinoma. METHODS: Seventy-two consecutive patients with advanced hypopharyngeal carcinoma were treated with pre- and postoperative radiotherapy (RTS), or preoperative concomitant chemoradiotherapy (CCRTS). Surgical procedures, including total laryngectomy plus partial pharyngectomy (TLPP) to preserve the posterior pharyngeal wall offering a functional neoglottis for esophageal or tracheoesophageal shunt phonation postoperatively, were conducted for patients who did not achieve CR. RESULTS: A significantly higher survival rate at 5 years (93.3%) was observed for N0-2b stage patients in the CCRTS group (n=16) than the RTS group (n=34; 41.5%) (p<.005). The distant metastasis-free rate was 92.9% (CCRTS group) versus 55.4% (RTS group) (p<.05) in these patients. In the CCRTS group, the 5-year survival rate with laryngeal or esophageal and/or tracheoesophageal shunt phonation was 22.2%. CONCLUSION: It is suggested that the CCRTS protocol and TLPP procedure may improve the survival rates without deterioration of phonatory rates in patients with N0-2b advanced hypopharyngeal carcinoma.

A phase I study of concurrent chemoradiotherapy with S-1 for T2N0 glottic carcinoma.

OBJECTIVE: Chemoradiation based on S-1, a novel oral antitumor agent of fluorinated pyrimidines, is the treatment for T2N0 glottic carcinoma; however, the optimal scheduling and dosing have still not been established. A phase I study was conducted to determine the maximum tolerated dose of S-1 with radiotherapy of 2 Gy/day for 5 days a week to a total dose of 60 Gy. Endpoints of this study were to examine the toxicity profile of this regimen and to determine the recommended dose of S-1. METHODS: Concomitant administration with the above-mentioned radiotherapy of S-1 once a day for 2 weeks, beginning on the day therapy was started, followed by 2 weeks off the drug and 2 weeks on the drug with the dose escalating from S-1 60 mg/body (level 1) to 80 mg/body/day (level 2), and then to 100 mg/body/day (level 3). RESULTS: Twenty-one patients were valid for safety. Eighteen patients were enrolled in the dose-escalation phase. In all patients, S-1 was administered. The maximum tolerated dose was determined to be 100 mg/body/day and the dose-limiting toxicity was indicated by the onset of grade 3 chemoradiation dermatitis. Therefore, the determined recommended dose of S-1 was 80 mg/body/day. Objective response according to Response Evaluation Criteria in Solid Tumors were observed in 20 of 21 patients who had measurable disease (95.2%). CONCLUSION: Concurrent S-1 and radiotherapy was feasible and well tolerated, and was suggested to produce a worthwhile response in T2N0 glottic carcinoma. These results warrant further investigation, and a phase II has already been started.

[Clinical phase I trial of concurrent chemo-radiotherapy with S-1 for T2NO glottic carcinoma].

We conducted a phase I study to determine a recommended dose (RD) of S-1 for chemo-radiotherapy consisting of S-1+ radiotherapy for T 2 N 0 larynx cancer. The method of administration used to assess the RD was irradiation with 2 Gy/day for 5 days a week until a total dose of 60 Gy, and concomitant administration of S-1 once a day for 2 weeks beginning on the day therapy was started followed by 2 weeks off the drug and 2 weeks on the drug with the dose escalating from S-1 60 mg/body/day (level 1) to 80 mg/body/day (level 2), and then to 100 mg/body/day (level 3). 18 patients were enrolled. 4 patients developed an adverse event of grade 3 radiation dermatitis which became a dose-limiting toxicity (DLT) at level 3. We then concluded that 100 mg/body/day was the maximum tolerated dose (MTD) of S-1 and decided that the RD of S-1 was 80 mg/body/day.

[Head and neck cancer treatment in the elderly--evaluation and management of complications].

With the population over age 70 growing, treatment for head and neck cancer in the elderly has increased. We retrospectively evaluated their management and outcome. Subjects numbered 121--83 men and 38 women from 70 to 94 years old--initially treated at our hospital. We classified them into 2 groups by age--the aged at 70-79 years (55 men and 26 women) and the very old at 80 years and older (28 men and 12 women). We also evaluated a younger control group aged 50-59 years (37 men and 19 women). Primary tumor sites were the oral cavity (28.1%), larynx (28.1%), paranasal sinus (15.8%), and hypopharynx (9.9%). Preoperative geriatric disease was seen in 54% of controls, 74% of the aged, and 93% of the very old. Cardiovascular and respiratory diseases were most common. Surgical treatment and irradiation were essential for cancer treatment. Postoperative complications, including pneumonia, delirium, renal and cardiovascular hypofunction occurred in 56.5% of controls, 48.2% of the aged, and 47.8% of the very old. The frequency of postoperative complications correlated significantly with the American Society of Anesthesiologist classification of physical status (ASA) and preoperative performance status (PS). The complications of irradiation including pneumonia, dehydration, and feeding disturbance occurred in 53% of the very old. Cures were achieved in 83.9% of controls, 81.5% of the aged, and 65.0% of the very old. Cause specific 5-year survival in those cured was 85.2% of controls, 84.5% of the aged, and 80.0% of the very old. Median survival in those not cured was 4 months in controls, 9.6 months in the aged, and 5 months in the very old. We concluded that curative treatment is important in the elderly, and the success of curative treatment and the prevention of complications depend on careful assessment of systemic disease, PS, ASA, and mental activity.