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.     

Africane-type sesquiterpenoids from the Argentine liverwort Porella swartziana and their antibacterial activity

Seven africanes (1, 2a,b, 3-6), two of them new (1, 2a), three secoafricanes (7-9), one of them new (7), and two norsecoafricanes (10, 11a), one of them new (10), all of them swartzianin-type, have been isolated from an Argentine collection of the endemic liverwort Porella swartziana. The structures of the new compounds were established by extensive 1D and 2D NMR spectroscopic data. Absolute configurations of compounds 2a, 2b, and 10 were derived on the basis of CD spectra. The compounds were tested for activity against a variety of microbes, but none were found to exhibit significant antibacterial activity.     

Staphylococcal enterotoxin B is involved in aggravation and recurrence of murine experimental autoimmune uveoretinitis via Vβ8CD4 T cells

Endogenous uveitis is a common cause of visual disability and blindness. The etiology of uveitis remains largely unknown but reasonable etiologic factors include infections. Superantigens are regarded as one of the leading causes of infectious etiology in autoimmune disease. However, the role of superantigens in uveitis remains unclear. In the present study, we investigated the effect of Staphylococcal enterotoxin B (SEB), a member of the superantigens, using an experimental model of autoimmune uveoretinitis (EAU). C57BL/6 mice were immunized with human interphotoreceptor retinoid binding protein (IRBP) peptide, and the severity of EAU disease was scored. Vehicle (PBS) alone or SEB dissolved in PBS was administered by intravenous injection on post-immunization day 10 or on post-immunization day 24. In addition, a systemic immune response study was performed to address the effects of SEB on systemic immunity. EAU was aggravated significantly by the injection of SEB at post-immunization day 10. Furthermore, relapse was induced by the injection of SEB at day 24. On the other hand, SEB injection without IRBP peptide immunization elicited no inflammatory changes in the uvea or retina. Furthermore, SEB enhanced not only the IRBP-specific T-cell proliferative responses but also IFN-γ and IL-17 production. Moreover, the intraocular expression levels of these cytokines was also enhanced by SEB injection. Both anti-CD4 and -Vβ8 Ab administration suppressed disease aggravation and the enhancement of IRBP-specific T-cell responses caused by SEB. These results suggest that SEB is involved significantly in the aggravation or recurrence of endogenous uveitis through activation of autoreactive uveitogenic T cells.     

Clinical features and treatment outcomes of dedifferentiated and grade 3 chondrosarcoma: A multi‐institutional study

Chondrosarcoma is the second most common primary malignant bone tumor. In this multicenter study, we sought to evaluate the disease‐specific survival (DSS) and disease‐free survival (DFS), and prognostic factors in patients with dedifferentiated chondrosarcoma (DDCS) or grade 3 chondrosarcoma (G3CS) in Japan. We retrospectively investigated the treatment outcomes and prognostic factors in 62 patients with DDCS and 19 patients with G3CS at 15 institutions participating in the Japanese Musculoskeletal Oncology Group. We also clarified significant clinicopathological factors for oncological outcomes. In surgery for primary lesions aimed at cure, a histologically negative margin (R0) was obtained in 93% (14/15) of patients with G3CS and 100% (49/49) of patients with DDCS. The 5‐year DSS was 18.5% in patients with DDCS and 41.7% in patients with G3CS (p = 0.13). Local control was obtained in 80% (12/15) and 79.6% (39/49) of patients with G3CS and DDCS in the primary lesion after surgery with a wide surgical margin, respectively. In multivariate analysis, stage and no treatment/palliative treatment for the primary lesion were independent prognostic factors for DSS of DDCS, and age and no treatment/palliative treatment for DSS of G3CS. The 5‐year DFS rate was 22.8% in 26 patients with DDCS who did not receive adjuvant chemotherapy, and 21.4% in 14 patients who received adjuvant chemotherapy. The prognosis of DDCS remains poor, although R0 resection was carried out in most cases. Effective and/or intensive chemotherapeutic regimens or agents should be considered or developed for patients with high‐grade chondrosarcoma, particularly for those with DDCS.     

Association of Eating Alone With Depression Among Older Adults Living Alone: Role of Poor Social Networks

ObjectivesEating alone is associated with an increased risk of depression symptoms. This association may be confounded by poor social networks. The present study aimed to determine the role of poor social networks in the association of eating alone with depression symptoms, focusing on cohabitation status.MethodsSeven hundred and ten community-dwelling older adults were categorized according to their eating style and social network size, evaluated using an abbreviated version of the Lubben Social Network Scale, with poor social network size (defined as the lowest quartile). Living arrangements and depression symptoms, detected using the Zung Self-Rating Depression Scale, were also assessed.ResultsA mixed-design two-way analysis of covariance (eating style and social network size factors) for the depression scale score, adjusted by covariates, yielded significant effects of social network size and eating style without interaction. Greater depression scores were observed in eating alone and poor social network size. Analysis of participants living with others showed the same results. However, among older adults living alone, only a significant main effect of social network size was observed; poor social network size resulted in greater depression scores irrespective of eating style.ConclusionsPoor social network size, and not eating alone, was associated with greater depression symptoms among older adults living alone, whereas both factors may increase depression symptoms among older adults living with others. Poor social network size may show a stronger influence on depression than eating alone in older adults living alone; thus, social network size is an important health indicator.Key words: eating alone, social network, living alone, depression, older adults     

Hypertrophic cardiomyopathy with progression from apical hypertrophy to asymmetrical septal hypertrophy: a case report

A 41-year-old man was referred to our hospital for further examination because of abnormal electrocardiography findings at a health-check examination. Transthoracic echocardiography showed left ventricular hypertrophy confined to the most distal portion of the left ventricle, which is a typical feature of apical hypertrophic cardiomyopathy. Ten years later, he was again admitted for the evaluation of chest pain. Echocardiography showed asymmetrical septal hypertrophy in addition to apical hypertrophy. These findings demonstrate morphologic evolution in hypertrophic cardiomyopathy from apical hypertrophy to asymmetrical septal hypertrophy.