Study on the Fatigue Crack Initiation and Growth Behavior in Bismuth- and Lead-Based Free-Cutting Brasses.

Several studies have been conducted on the fatigue behavior of copper and 7-3, and 6-4 brasses. However, there have been fewer studies on the fatigue behavior and fatigue crack growth (FCG) properties of free-cutting brass, primarily because emphasis has been placed on the development of lead-free free-cutting brass. In this study, fatigue experiments were performed in the atmosphere at room temperature using three types of free-cutting, two types of bismuth (Bi)-based (with different grain sizes), and lead (Pb)-based brasses. It was found that lead-free Bi-based free-cutting brass had approximately the same fatigue performance as that of Pb-based free-cutting brass. It was also clarified that the addition of Bi or Pb initiated fatigue cracks, and that the crack growth period occupied most of the fatigue life. Differences in the FCG behavior of the three free-cutting brasses were observed in the low ΔK range. The modified linear fracture mechanics parameter M was used to quantitatively analyze the fatigue life and FCG behavior (short surface cracks). A comparison between the calculated and experimental results showed that M was useful.

Elasto-Plastic Fatigue Crack Growth Behavior of Extruded Mg Alloy with Deformation Anisotropy Due to Stress Ratio Fluctuation.

Fatigue crack growth (FCG) experiments were performed using a low-temperature extruded magnesium alloy AZ31 with texture. Under a constant maximum stress intensity factor (Kmax), the stress ratio R was changed from 0.1 to -1 during the fatigue crack growth process, and the FCG behavior before and after the R change was investigated. As a result, tensile twins were generated owing to the fatigue load on the compression side of R = -1, and the FCG velocity was accelerated. In addition, when the maximum compressive stress at R = -1 (|(σmin)R = -1|) exceeded the compressive yield strength of the material (σcy), the FCG velocity after R fluctuation greatly accelerated. On the other hand, under the condition |(σmin)R = -1| < σcy, the degree of acceleration of the FCG velocity due to R fluctuation was small. In either case, the degree of acceleration in the FCG increased as the Kmax value increased. The above FCG acceleration mechanism due to the R fluctuation was considered based on the observation of the deformation and twinning states of the fatigue crack tip, the fatigue crack closure behavior, and the cyclic stress-strain curve of the fatigue process. The FCG acceleration mechanism was as follows: First, the driving force of the FCG increased owing to the increase in crack opening displacement due to the generation of tensile twins. Second, the coalescence of the main crack and a plurality of microcracks were generated at the twin interface. The elasto-plastic FCG behavior after the stress ratio fluctuations is defined by the effective J-integral range ΔJeff.

[Breast Cancer Patient with Bone Metastases Who Was Able to Return Home without Using Opioids after Administration of Strontium-89 Chloride].

A 46-year-old woman underwent mastectomy for right inflammatory breast cancer.Three years later, she was diagnosed with multiple bone metastases and was treated with systemic chemotherapy and zoledronic acid.Six years after the mastectomy, she complained of severe sacral pain, and 40 Gy external radiotherapy was applied to the sacral metastases.Oxycodone was also administered, but dose escalation was difficult because of severe nausea and fatigue.A bone scan showed increased uptake of Tc99m in an area consistent with the painful regions, and an injection of 89SrCl2 was administered.Five weeks after the injection, her severe pain was relieved and she was able to discontinue the use of opioids completely.She successfully lived at home for 100 days without using opioids.In this case, radionuclide therapy with 89SrCl2 led to remarkable pain relief with an improvement in the quality of life of the patient.

[A Case of Drug-Induced Lung Injury Associated with Paclitaxel plus Bevacizumab Therapy].

A 61-year old woman with recurrent breast cancer received combined treatment with paclitaxel (PTX) and bevacizumab (BV) as the third-line chemotherapy. During the administration of PTX in the 3 courses of chemotherapy, she suddenly developed respiratory failure, and both chest X-ray and CT revealed bilateral pulmonary infiltrates. Symptoms and radiographic findings responded dramatically to steroid pulse therapy. The history of onset and laboratory data showed no evidence of infection; therefore, we made a diagnosis of acute lung injury induced by the chemotherapy. It should be noted that lung injury may be induced by both PTX and BV, and is one of the important adverse events despite the low frequency of occurrence.

[A case report of recurrent small bowel adenocarcinoma successfully treated with monoclonal antibody against EGFR and S-1].

A man in 30s was admitted to our hospital with a complaint of abdominal and back pain. Abdominal CT scan showed a large mass and double balloon endoscopy detected a tumor of the jejunum. The pathological diagnosis of biopsy samples was poorly differentiated adenocarcinoma. After radical resection, adjuvant chemotherapy with mFOLFOX6 was administered, however, a recurrent lesion developed. Although the lesion was successfully removed again, it did not react to the combination therapy with irinotecan and cisplatin. Because the tumor showed a high percentage of epidermal growth factor receptor (EGFR) expression and also had a wild-type KRAS status, a therapeutic strategy targeting EGFR was selected. The patient started on panitumumab associated with S-1 and obtained a complete response on CT 6 weeks later. Small bowel adenocarcinoma is an aggressive malignancy with a poor prognosis and little information about its definitive chemotherapy. Analysis of molecular characterization, an increase in reported experience, and prospective trials are needed to improve a prognosis.

[Role of palliative chemotherapy and shift from anticancer therapy to palliative care in patients with advanced or recurrent breast cancer].

We examined the role of palliative chemotherapy and the shift from anticancer therapy to palliative care in 30 patients who had died of advanced or recurrent breast cancer. Patients who received more than four chemotherapy regimens had a longer survival and started analgesics later than those who received less than three regimens. In addition, median survival time was prolonged in patients treated with both anthracycline- and taxane-containing regimens. Presence of bone metastases did not influence survival time, but extended the period of last hospitalization. In the average process of advanced or recurrent breast cancer, use of analgesics was started on the 500 th day and the last hospitalization was on the 760 th day from the diagnosis. Last chemotherapy was performed 29 days before death, and the median survival length was 811 days. Patients were treated as outpatients in 94% of the period from their recurrence until death. Therefore, it is especially important to support outpatients physically and mentally from the early stage of recurrence.

Laparoscopy-assisted and open distal gastrectomies for early gastric cancer at a general hospital in Japan.

BACKGROUND/AIMS: At general hospitals in Japan, laparoscopic surgery for early gastric cancer is not yet popular. The benefits and feasibility of this procedure remain to be established. The aim of this study was to evaluate the surgical outcome of laparoscopy-assisted distal gastrectomy (LADG) in comparison with open distal gastrectomy (ODG) in a general hospital. METHODOLOGY: We performed LADG in 20 patients with early gastric cancer between 2000 and 2001. Clinicopathologic data, blood analyses, clinical course and financial cost of treating patients with LADG were compared with 22 patients treated with ODG between 1998 and 1999. RESULTS: All patients were treated successfully by LADG. Neither reduced operative curability nor increased complications were found with this procedure. Although LADG required a significantly longer operation time than ODG, blood loss was lower in LADG than in ODG. The leukocyte count on day 1 and day 3, and serum C-reactive protein levels on day 1 were significantly lower after LADG than after ODG. There was no significant difference between LADG and ODG in the period and volume of analgesics required. High body temperature continued longer after ODG than after LADG. The first walking, passage of flatus and oral diet initiation were significantly earlier in patients with LADG than in those with ODG. LADG required a significantly shorter hospital stay and less total hospital charge than ODG. CONCLUSIONS: Laparoscopy-assisted distal gastrectomy offered faster recovery of gastrointestinal function, a shorter hospital stay, and consequently less financial cost when compared with open surgery. Therefore, LADG may be a safe and recommendable procedure for patients with early gastric cancer at general hospitals in Japan.

[A case of advanced gastric cancer with peritoneal metastases responding to bi-weekly paclitaxel therapy].

A 68-year-old man underwent bypass operation for gastric cancer, because the tumor was judged to be unresectable due to peritoneal dissemination. After the operation, the patient was treated with daily oral administration of 100 mg TS-1 for two weeks followed by one week rest as one cycle. However, symptoms such as anemia, ascites and edema became worse and the TS-1 resulted in progressive disease. Bi-weekly paclitaxel therapy (80 mg/m2/2 weeks) was then chosen as second line chemotherapy. Anemia and edema were reduced and computed tomography showed shrinkage in the size of lymph nodes and disappearance of ascites. Only grade 1 alopecia was observed as an adverse event during the therapy. Bi-weekly paclitaxel therapy could be safe and useful as the second line therapy.