Studies toward the Synthesis of Biologically Important, Natural and Artificial Small Molecules

Shown in this article are our current research topics based on the organic syntheses of biologically important molecules. The synthetic studies on marine natural products, dysiherbaines, azaspiracids, and goniodomin are described. Another research aiming to discover biologically functional small molecules from artificial synthetic libraries is also described

Mental Retirement: Evidence from Global Aging Data

This study analyzes the effect of retirement on cognitive function; specifically, the hypothesis from human capital theory that because cognitive investment increases a worker's wage, workers may invest in their cognitive ability more than retirees, contributing to a post-retirement decline in cognitive function. While this topic is of great interest to health economics, we show that the method of analysis of some previous studies is not valid for examining this effect, and we propose an alternative method that addresses this concern. Further, our estimates indicate that retirement has only a weak effect on cognitive ability in a wide range of analyzed countries and heterogeneous groups. Therefore, according to our analysis, policies that have been widely adopted in developed countries to delay retirement, such as increasing the pensionable age, appear to have little detrimental affect on post-retirement cognitive ability

Mental Retirement: Evidence from Global Aging Data

This study analyzes the effect of retirement on cognitive function; specifically, the hypothesis from human capital theory that because cognitive investment increases a worker's wage, workers may invest in their cognitive ability more than retirees, contributing to a post-retirement decline in cognitive function. While this topic is of great interest to health economics, we show that the method of analysis of some previous studies is not valid for examining this effect, and we propose an alternative method that addresses this concern. Further, our estimates indicate that retirement has only a weak effect on cognitive ability in a wide range of analyzed countries and heterogeneous groups. Therefore, according to our analysis, policies that have been widely adopted in developed countries to delay retirement, such as increasing the pensionable age, appear to have little detrimental affect on post-retirement cognitive ability

What Explains the Difference in the Effect of Retirement on Health?: Evidence from Global Aging Data

This paper analyzes the reasons for differences in the effect of retirement on health estimated results in previous studies. We investigate these differences by focusing on the analysis methods used by these studies. Using various health indexes, numerous researchers have examined the effects of retirement on health. However, there are no unified views on the impact of retirement on various health indexes. Consequently, we show that the choice of analysis method is one of the key factors in explaining why the estimated results of the effect of retirement on health differ. Moreover, we re-estimate the effect of retirement on health by using a fixed analysis method controlling for individual heterogeneity and endogeneity of the retirement behavior. We analyze the effect of retirement on health parameters, such as cognitive function, self-report of health, activities of daily living (ADL), depression, and body mass index in eight countries. We find that the effects of retirement on self-report of health, depression, and ADL are positive in many of these countries

Retirement and Health Investment Behaviors: An International Comparison

This study aims to better understand the effects of retirement on health outcomes, which is of great interest worldwide, by examining the effects of retirement on health investment behaviors. To this end, we conducted a large-scale international comparison of the changes in health investment behaviors after retirement among the populations of seven developed countries using Global Aging Data, exploiting differences in the financial incentives in the pension systems of each country as our identification strategy. The results show that while elderly change their health investment behaviors in some way after retirement, the patterns of the changes in many health investment behaviors differ across each country. Further, a review of the literature and our results suggest that health investment behaviors are not necessarily determinants of the effects of retirement on health

Examining the Changes in Health Investment Behavior After Retirement: A Harmonized Analysis

This study examines the effects of retirement on health investment behaviors. We conduct a large-scale international comparison of the change in health investment behaviors after retirement among 9 developed countries, using harmonized datasets. We find that the changes in some of health investment behaviors (e.g., Exercise) are improved in most of the countries. With respect to exercise, the change in the opportunity cost to exercise after retirement is a possible reason to explain this improvement

Retirement and Cognitive Decline: Evidence from Global Aging Data

This study analyzes the effect of retirement on cognitive function. According to the human capital theory, we can hypothesize that workers invest in their cognitive ability more than retirees because cognitive investment increases a worker’s wage. As a result, it is possible that the cognitive ability decreases after retirement, a hypothesis analyzed in this study. In health economics, this hypothesis has been examined especially after 2000. First, we show that an analysis method used in some related studies is not valid for estimating this effect. Furthermore, we analyze this effect by using our method. Our estimates indicate that the workers’ mathematical scores decrease after retirement in a wide range of analyzed countries and heterogeneous groups. However, retirement has a weak effect on cognitive ability. Additionally, we investigate the heterogeneity of this effect. For example, we find that the elderly with higher body mass indexs and fat intake experience a negative effect of retirement on cognitive function

What Explains the Difference in the Effect of Retirement on Health?: Evidence from Global Aging Data

This paper analyzes the reasons for differences in the effect of retirement on health estimated results in previous studies. We investigate these differences by focusing on the analysis methods used by these studies. Using various health indexes, numerous researchers have examined the effects of retirement on health. However, there are no unified views on the impact of retirement on various health indexes. Consequently, we show that the choice of analysis method is one of the key factors in explaining why the estimated results of the effect of retirement on health differ. Moreover, we re-estimate the effect of retirement on health by using a fixed analysis method controlling for individual heterogeneity and endogeneity of the retirement behavior. We analyze the effect of retirement on health parameters, such as cognitive function, self-report of health, activities of daily living (ADL), depression, and body mass index in eight countries. We find that the effects of retirement on self-report of health, depression, and ADL are positive in many of these countries

Retirement and Health Investment Behaviors: An International Comparison

This study aims to better understand the effects of retirement on health outcomes, which is of great interest worldwide, by examining the effects of retirement on health investment behaviors. To this end, we conducted a large-scale international comparison of the changes in health investment behaviors after retirement among the populations of seven developed countries using Global Aging Data, exploiting differences in the financial incentives in the pension systems of each country as our identification strategy. The results show that while elderly change their health investment behaviors in some way after retirement, the patterns of the changes in many health investment behaviors differ across each country. Further, a review of the literature and our results suggest that health investment behaviors are not necessarily determinants of the effects of retirement on health