This study explores the impact of pinna hardness and vibrator placement on the efficacy of bone conduction through the pinna. Hearing thresholds of twelve participants, all without abnormal pinna conditions, were assessed across frequencies ranging from 250 Hz to 8 kHz, with vibrators positioned at three distinct locations—the front of the ear canal, the earlobe, and behind the cymba concha. Additionally, with a focus on consistent variable manipulation in a controlled experimental scenario, four silicone ear models with Shore hardness values from 0A to 45A were utilized to examine vibrational energy transmission via an accelerometer fixed behind the ear canal. The results indicated that vibrator placement significantly influenced hearing thresholds, a pattern that was also observed in the silicone models. However, the anticipated correlation between pinna hardness and hearing thresholds was not significant within the human sample. This could be attributed to less variability in natural pinna hardness than expected. While it is recognized that pinna hardness varies among individuals, our study reveals a less dramatic variation in pinna hardness among individuals, suggesting that its influence on bone conduction may be less critical than other anatomical factors.

Volatile anesthetics accelerate dopamine turnover in the brain, especially when used in conjunction with psychotropic agents such as methamphetamine and nomifensine. The effect of intravenous propofol anesthesia on the extracellular dopamine concentrations is unclear. The aim of this study was to compare the effect of two anesthetics on the extracellular concentrations of dopamine and metabolites using an in vivo microdialysis model. Male Sprague Dawley rats were implanted with a microdialysis probe into the right striatum. The probe was perfused with modified Ringer’s solution, and the dialysate was directly injected into a high-performance liquid chromatography system every 20 min. The rats were intraperitoneally administered saline, methamphetamine at 2 mg/kg, or nomifensine at 10 mg/kg. After treatment, the rats were anesthetized with intravenous propofol (20 mg/kg followed by 25 or 50 mg/kg/h) or inhalational sevoflurane (2.5%) for 1 h. Propofol showed no effect on the extracellular concentration of dopamine during anesthesia; however, propofol decreased the dopamine concentration after anesthesia in the high-dose group. Sevoflurane anesthesia increased the concentration of metabolites. Systemic administration of methamphetamine and nomifensine increased the extracellular concentration of dopamine. Sevoflurane anesthesia significantly enhanced the increase in the dopamine concentration induced by both methamphetamine and nomifensine, whereas propofol anesthesia showed no effect on the methamphetamine- and nomifensine-induced dopamine increase during anesthesia. The enhancing effect of psychotropic agent-induced acceleration of dopamine turnover was smaller for propofol anesthesia than for sevoflurane anesthesia.

グローバリゼーションの下で国境を越えた生産の分業が進み，ファッション産業ではファストファッションが世界市場を席巻している．この現象を生産面から見ると，ロシア企業もグローバル企業に追随してアジアへ製造拠点を移転させている．現在のロシアへの生産回帰も一時的な現象にすぎない．一方，販売の面から見ると，ロシア企業は市場の特性の近い旧ソ連圏を足掛かりとして海外進出を図っている．

近年、新興国発の多国籍企業（EM-MNEs）は、グローバル市場においてプレゼンスを急速に高めている。本稿は、これらの企業の異質な国際化プロセス、いわゆる「二重の国際化」に焦点を当て、どのような戦略が用いられるかを検証することを研究目的とする。そこで、中国のアリババ・グループを代表事例として取り上げ、先進国と新興国市場における当該企業の国際戦略についてそれぞれ考察した。その結果、EM-MNEsが二重の国際化を行う際、先進国市場においては、資源探索型の戦略志向が強く、また、市場の異質性を考慮した適応化戦略を用いて対応するのに対し、母国と類似性の高い新興国市場においては、資源活用型の戦略志向が強く、標準化戦略を駆使するという結論を導き出した。