In order to examine the threshold condition for the fatigue limit of materials containing a small crack under cyclic torsion, reversed torsional fatigue tests were carried out on 0.47% C steel specimens containing an initial small crack. Initial small semi‐elliptical cracks ranging from 200 to 1000 μm in length were introduced by the preliminary tension–compression fatigue tests using specimens containing holes of 40 μm diameter. The threshold condition for the fatigue limit of the specimens containing artificial small defects under rotating bending and cyclic torsion are also reviewed. Crack growth behaviour from an initial crack was investigated. The torsional fatigue limit for a semi‐elliptical small crack is determined by the threshold condition for non‐propagation of Mode I branched cracks. The torsional fatigue limit of specimens containing an initial small crack can be successfully predicted by the extended application of the √area parameter model in combination with the σθmax criterion.

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Objective  To determine differences in the immunohistochemical (IHC) expression of Bcl‐2 protein and Ki‐67 antigen in patients with prostatic cancer who underwent radical prostatectomy with or without neo‐adjuvant hormonal therapy. Materials and methods  Ki‐67 antigen and Bcl‐2 protein were detected by IHC using MIB‐1 and Bcl‐2 antibodies in prostatectomy specimens from 28 patients who received hormonal therapy before surgery (group 1) and 51 patients who did not (group 2). Results  In group 2, the mean MIB‐1 index increased with increasing grade of tumour, from 11.6% in low‐grade to 24.7% in high‐grade tumours (P=0.002). Bcl‐2 expression did not correlate with either tumour grade or stage. In group 1, there were no correlations between Bcl‐2 expression or MIB‐1 index and tumour grade or stage. More tumours in group 1 were Bcl‐2‐positive (16 of 28, 57%) than were tumours in group 2 (11 of 51, 22%; P=0.003). The mean (sd) MIB‐1 index of tumours in group 2 [15.6 (14.4)%], was significantly greater than that of tumours in group 2 [6.8 (7.5)%; P=0.004]. Conclusions  These results indicate that Bcl‐2 positivity is increased by androgen ablation therapy and conversely, that the proliferative activity of cancer cells is significantly reduced. The expression of Bcl‐2 protein may play a role in the ability of prostate cancer cells to survive in an androgen‐deprived environment.

The basic approach to the problem of torsional fatigue strength of pieces containing defects is based on the stress concentration factor concept. However, experiments have shown that the torsional fatigue limit of specimens containing small holes is controlled by the threshold condition for small cracks emanating from small notches. Therefore, the ratio of torsional to bending fatigue limit (τw /σw ) for specimens containing small defects must be studied from the viewpoint of fracture mechanics. The scope of this paper is to address the calculation of the stress intensity factor for a small crack emanating from a three‐dimensional hole under a biaxial state of stress by using the weight function method and to apply it to the fatigue limit prediction. The results obtained are in good agreement with experimental results on specimens with defects.

Direct-acting antiviral (DAA) therapy for chronic hepatitis C virus (HCV) infection patients (CH) results in a sustained viral response (SVR) in over 95% of patients. However, hepatocellular carcinoma (HCC) occurs in 1–5% of patients who achieved an SVR after treatment with interferon. We attempted to develop a minimally invasive and highly reliable method of predicting the occurrence and recurrence of HCC in patients who achieved an SVR with DAA therapy. The exosomal miRNA expression patterns of 69 CH patients who underwent HCC curative treatment and 70 CH patients were assessed using microarray analysis. We identified a miRNA expression pattern characteristic of SVR-HCC by using machine learning. Twenty-five of 69 patients had HCC recurrence. The expression of four exosomal miRNAs predicted HCC recurrence with 85.3% accuracy. Fifteen of 70 patients had HCC occurrence. The expression of four exosomal miRNAs predicted the onset of HCC with 85.5% accuracy. The expression patterns of miR-4718, 642a-5p, 6826-3p, and 762 in exosomes were positively correlated with those in the liver, and downregulation of these miRNAs induced cell proliferation and prevented apoptosis in vitro. Aberrant expression of four miRNAs, which was used for prediction, was associated with HCC onset after HCV eradication. Expression patterns of exosomal miRNAs are a promising tool to predict SVR-HCC.