Use it too much and lose everything? The effects of hours of work on health.

In this paper, we extend the 'use it or lose it' hypothesis to analyse whether the negative effects of working hours eventually dominate the positive effects of work as the hours of work increase. Using panel data from the HILDA survey, we estimate the optimal hours of work for the health status of middle age and elderly workers. We deal with the potential endogeneity of working hours by using the instrumental variable estimation technique with instruments based on the age for pension eligibility. For males working relatively moderate hours (up to around 24-27 h a week), an increase in working hours has a positive impact on their health outcomes, but thereafter an increase in working hours has a negative impact on health outcomes. When weekly working hours exceed 50 h, an individual's health status is worse off than when he is not working at all.

The return of sleep.

While most individuals spend a substantial amount of time sleeping, Japan is among the developed countries whose residents register the fewest number of hours of sleep. I thus examine the causal effects of sleep on labor productivity, utilizing panel datasets for Japanese men. The potential endogeneity of deciding how many hours to sleep is addressed by using fixed effects panel data models with an instrumental variable estimation technique. Exploiting the annual variation in the average sunshine duration between cities as an instrument, I then show that a one-hour increase in the weekly number of hours of sleep increases the wage rate by up to 6-8% on average. These results suggest that sleep duration could enhance labor productivity.

Information feedback in relative grading: Evidence from a field experiment.

Previous studies have revealed the role of relative performance information feedback on providing agent incentives under a relative rewarding scheme through laboratory experiments. This study examines the impact of relative performance information feedback of students' performance on their examination score under the relative grading scheme in an actual educational environment. Conducting a randomized controlled trial in a compulsory subject at a Japanese university, we show that the relative performance information feedback has a significantly positive impact on the students' examination score on average, but that the average positive impact is derived by the improvement of low-performing students.

Properties of precipitate of creaming down by (-)-epigallocatechin-3-O-gallate and caffeine.

An aqueous solution of equimolecular amounts of gallated catechin (-)-epigallocatechin-3-O-gallate (EGCg) and caffeine afforded a crude precipitate by creaming, which crystallized slowly for about three months at 10°C to give a colorless block crystal. The crystal was determined to be a 2 : 2 complex of EGCg and caffeine by X-ray crystallographic analysis. The 2 : 2 complex was formed with the cooperative effect of three intermolecular interactions, π-π and CH-π interactions, and intermolecular hydrogen bonds. Upon formation of the 2 : 2 complex, a caffeine molecule was captured by a hydrophobic space formed by the aromatic rings A, B, and B' rings of two EGCg molecules. Judging from the entropy value, the shift value in the chemical shift of proton signals in (1)H-NMR spectra, the NT1 value, and nuclear Overhauser effects (NOEs), it was thought that the structure of complexes of EGCg and caffeine in aqueous solution were the same as their crystal structure.

[Causes of emergency hospitalization of elderly diabetic patients].

In recent years there has been a rise in the number of diabetic patients in Japan, with the increase in elderly diabetic patients becoming a serious problem. This study looked at 488 elderly type 2 diabetes patients who were admitted as emergency cases to the Department of Internal Medicine, JA Yoshida General Hospital, Akitakada City, Japan. All patients were classified by age into three groups: <70, 70-80 and >80. The most common cause of emergency hospitalization in each of the three age groups was infection. This was significantly higher in the >80 group in comparison with<70 (p<0.05). The most common infection among the three groups was respiratory infection, followed by urinary tract infection. The number of emergency hospitalization cases due to hypoglycemia was much higher in the over 80 group, particularly in comparison with<70-80 (p<0.05). The incidence of hypoglycemia in our patients could be explained mainly by reduced energy intake. Most cases were treated with oral administration of hypoglycemic drugs. As elderly diabetic patients have a number of underlying illnesses that are prone to aggravation and may lead to unfavorable prognosis, early medical examination and disease detection are considered to be important. Pharmacists are required to educate patients, home-visit nursing care personnel on sick-day rule, and provide diabetes care.

Configurational studies of complexes of tea catechins with caffeine and various cyclodextrins.

A suspension of an equimolecular amount of ENT-gallocatechin-3-O-gallate ( ENTGCg) and caffeine in water afforded two kinds of crystals, which were 1 : 2 and 2 : 2 complexes of ENTGCg and caffeine. The stereochemical structures and intermolecular interactions between ENTGCg and caffeine were determined by X-ray crystallographic analysis. The crystal structure of ENTGCg was determined and compared with those of the 1 : 2 and 2 : 2 complexes. Epigallocatechin-3-O-gallate (EGCg) formed a 1 : 1 complex with ß-cyclodextrin (CD), in which the aromatic A ring and a part of the heterocyclic C ring were included from the wide secondary hydroxyl group side of the ß-CD cavity in aqueous solution, while the B rings and 3-O-gallate groups (B' rings) were left outside the cavity. In contrast, ENTGCg formed a 1 : 2 complex with ß-CD, in which the aromatic A and B rings of ENTGCg were included by two molecules of ß-CD.

Diastereomeric difference of inclusion modes between (-)-epicatechin gallate, (-)-epigallocatechin gallate and (+)-gallocatechin gallate, with beta-cyclodextrin in aqueous solvent.

Inclusion complexes of (-)-epicatechin gallate (ECg) as well as (+)-gallocatechin gallate (GCg) and beta-cyclodextrin (beta-CD) in an aqueous solution were investigated using several NMR techniques and a computational method. ECg and EGCg formed a 1:1 complex with beta-CD, in which the A ring and a portion of the C ring were included from the wide secondary hydroxyl group side of the beta-CD cavity, and the B and B' rings were left outside the cavity. GCg formed a 1:2 complex with beta-CD, in which the A and B rings of GCg were included by two molecules of beta-CD. The difference between the two modes of inclusion of the 1:1 complex of ECg, EGCg.beta-CD and the 1:2 complex of GCg.beta-CD might have resulted from the size of the space between the B and B' rings in aqueous solution. As a result of nuclear Overhauser effect (NOE) experiments, GCg was considered to have a large enough space between the B and B' rings to include the B ring in the beta-CD cavity; on the other hand, ECg and EGCg have no such large space.