Optical conductivity from local anharmonic phonons

Recently there has been paid much attention to phenomena caused by local anharmonic vibrations of the guest ions encapsulated in polyhedral cages of materials such as pyrochlore oxides, filled skutterdites and clathrates. We theoretically investigate the optical conductivity solely due to these so-called rattling phonons in a one-dimensional anharmonic potential model. The dipole interaction of the guest ions with electric fields induces excitations expressed as transitions among vibrational states with non-equally spaced energies, resulting in a natural line broadening and a shift of the peak frequency as anharmonic effects. In the case of a single well potential, a softening of the peak frequency and an asymmetric narrowing of the line width with decreasing temperature are understood as a shift of the spectral weight to lower level transitions. On the other hand, the case of a double minima potential leads to a multi-splitting of a spectral peak in the conductivity spectrum with decreasing temperature.Comment: 8 pages, 11 figures, accepted for publication in Phys. Rev.

A questionnaire-based comparative study of postoperative quality of life between laryngotracheal separation and tracheoesophageal diversion

Purpose: Whether tracheoesophageal diversion (TED) is preferable to laryngotracheal separation (LTS) is unclear. This study examined the need for tracheoesophageal anastomosis by reviewing complications after TED and LTS and administering a questionnaire on postoperative quality of life.Patients and methods: Medical records of TED/LTS cases performed at a single institution from 2003 to 2015 were retrospectively reviewed and a questionnaire was administered to parents of patients at an outpatient visit.Results: A total of 40 TED and 18 LTS cases were included. Complications occurred in six TED cases and one LTS case, with no significant differences between groups (P=0.42). A total of 22 parents of patients (TED 16 cases; LTS six cases) completed the questionnaire. Voice production was reported in three TED cases and two LTS cases. Patients indicated that suctions were ‘decreased’ in 13 and ‘unchanged’ in two TED cases, but ‘decreased’ in one and ‘unchanged’ in five LTS cases (P=0.0055). Readmissions were ‘increased’ in one and ‘decreased’ in 14 TED cases, but ‘decreased’ in three and ‘unchanged’ in three LTS cases (P=0.015).Conclusion: Postoperative complication rate was equivalent between groups, and the numbers of suctions and readmissions were decreased in the TED group. Therefore, tracheoesophageal anastomosis should be performed more commonly.Keywords: complication, laryngotracheal separation, quality of life questionnaire, tracheoesophageal diversio

Effects of iguratimod on glucocorticoid-induced disorder of bone metabolism in vitro

Introduction: Glucocorticoids are widely used to treat various diseases including rheumatoid arthritis (RA); however, one of the most frequent and severe adverse effects is glucocorticoid-induced osteoporosis (GIOP). Iguratimod (IGU) is a novel conventional synthetic disease-modifying anti-rheumatic drug developed in Japan. The aim of this study is to investigate the effects of IGU on glucocorticoid-induced disorder of bone metabolism in vitro. Materials and methods: In osteoclastogenesis of mouse bone marrow-derived cells, tartrate-resistant acid phosphatase staining, resorption pit assay, western blotting, real-time polymerase chain reaction (PCR), and mRNA sequencing were performed. In osteoblastogenesis of MC3T3-E1 cells, alkaline phosphatase (ALP) staining and activity, alizarin red staining, and mRNA sequencing were performed, and real-time PCR and western blotting were conducted in MC3T3-E1 cells and murine osteocyte-like cell line MLO-Y4 cells. Results: IGU significantly suppressed a dexamethasone-induced increase in osteoclasts, differentiation, and bone resorption activity by inhibition of the receptor activator of the nuclear factor kappa-B (RANK)/tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6)/nuclear factor kappa-B (NFκB)-p52 pathway. In MC3T3-E1 cells, IGU significantly upregulated dexamethasone-induced downregulation of ALP activity, bone mineralization, and osteoblast-related gene and protein expression. In MLO-Y4 cells, IGU significantly upregulated dexamethasone-induced downregulation of the gene expression of ALP and osteocalcin, and also downregulated receptor activator of NFκB ligand (RANKL)/osteoprotegerin gene expression ratio without dexamethasone. Conclusion: These results suggest that IGU may improve glucocorticoid-induced disorder of bone metabolism and may exhibit positive effects against GIOP associated with RA.This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s00774-021-01206-5Miyama A., Ebina K., Hirao M., et al. Effects of iguratimod on glucocorticoid-induced disorder of bone metabolism in vitro. Journal of Bone and Mineral Metabolism 39, 639 (2021

Basic fibroblast growth factor promotes meniscus regeneration through the cultivation of synovial mesenchymal stem cells via the CXCL6–CXCR2 pathway

Objective: To investigate the efficacy of basic fibroblast growth factor (bFGF) in promoting meniscus regeneration by cultivating synovial mesenchymal stem cells (SMSCs) and to validate the underlying mechanisms. Methods: Human SMSCs were collected from patients with osteoarthritis. Eight-week-old nude rats underwent hemi-meniscectomy, and SMSCs in pellet form, either with or without bFGF (1.0 × 106 cells per pellet), were implanted at the site of meniscus defects. Rats were divided into the control (no transplantation), FGF (−) (pellet without bFGF), and FGF (+) (pellet with bFGF) groups. Different examinations, including assessment of the regenerated meniscus area, histological scoring of the regenerated meniscus and cartilage, meniscus indentation test, and immunohistochemistry analysis, were performed at 4 and 8 weeks after surgery. Results: Transplanted SMSCs adhered to the regenerative meniscus. Compared with the control group, the FGF (+) group had larger regenerated meniscus areas, superior histological scores of the meniscus and cartilage, and better meniscus mechanical properties. RNA sequencing of SMSCs revealed that the gene expression of chemokines that bind to CXCR2 was upregulated by bFGF. Furthermore, conditioned medium derived from SMSCs cultivated with bFGF exhibited enhanced cell migration, proliferation, and chondrogenic differentiation, which were specifically inhibited by CXCR2 or CXCL6 inhibitors. Conclusion: SMSCs cultured with bFGF promoted the expression of CXCL6. This mechanism may enhance cell migration, proliferation, and chondrogenic differentiation, thereby resulting in superior meniscus regeneration and cartilage preservation.Goshima A., Etani Y., Hirao M., et al. Basic fibroblast growth factor promotes meniscus regeneration through the cultivation of synovial mesenchymal stem cells via the CXCL6–CXCR2 pathway. Osteoarthritis and Cartilage , (2023); https://doi.org/10.1016/j.joca.2023.07.010