Malaria parasites regulate the duration of the intra-erythrocytic cycle via serpentine receptor 10 and coordinate development with host daily rhythms

Malaria parasites complete their intra-erythrocytic developmental cycle (IDC) in multiples of 24 h suggesting a circadian basis, but the mechanism controlling this periodicity is unknown. Combining in vivo and in vitro approaches utilizing rodent and human malaria parasites, we reveal that: (i) 57% of Plasmodium chabaudi genes exhibit daily rhythms in transcription; (ii) 58% of these genes lose transcriptional rhythmicity when the IDC is out-of-synchrony with host rhythms; (iii) 6% of Plasmodium falciparum genes show 24 h rhythms in expression under free-running conditions; (iv) Serpentine receptor 10 (SR10) has a 24 h transcriptional rhythm and disrupting it in rodent malaria parasites shortens the IDC by 2-3 h; (v) Multiple processes including DNA replication, and the ubiquitin and proteasome pathways, are affected by loss of coordination with host rhythms and by disruption of SR10. Our results reveal malaria parasites are at least partly responsible for scheduling the IDC and coordinating their development with host daily rhythms

Municipal health expectancy in Japan: decreased healthy longevity of older people in socioeconomically disadvantaged areas

BACKGROUND: Little is known about small-area variation in healthy longevity of older people and its socioeconomic correlates. This study aimed to estimate health expectancy at 65 years (HE65) at the municipal level in Japan, and to examine its relation to area socio-demographic conditions. METHODS: HE65 of municipalities (N = 3361) across Japan was estimated by a linear regression formula with life expectancy at 65 years and the prevalence of those certificated as needing nursing care. The relation between HE65 and area socio-demographic indicators was examined using correlation coefficients. RESULTS: The estimated HE65 (years) ranged from 13.13 to 17.39 for men and from 14.84 to 20.53 for women. HE65 was significantly positively correlated with the proportion of elderly and per capita income, and negatively correlated with the percentage of households of a single elderly person, divorce rate, and unemployment rate. These relations were stronger in large municipalities (with a population of more than 100,000) than in small and medium-size municipalities. CONCLUSION: A decrease in healthy longevity of older people was associated with a higher percentage of households of a single elderly person and divorce rate, and lower socioeconomic conditions. This study suggests that older people in urban areas are susceptible to socio-demographic factors, and a social support network for older people living in socioeconomically disadvantaged conditions should be encouraged

Flash boiling spray of diesel fuel mixed with ethane and its effects on premixed diesel combustion

Mixtures of gaseous and liquid fuels have the potential to induce flash boiling under in-cylinder conditions close to the top dead center, something that can be expected to be suitable for a premixed diesel combustion that demands a way to enhance lean mixture formation. The present study mixes ethane, which is a natural gas component, into diesel fuel as ethane has a high vapor pressure that facilitates flash boiling and as ethane has a low cetane number that prolongs the ignition delay. This paper investigates spray characteristics of a diesel fuel-Ethane mixture, and the engine performance and exhaust emissions are evaluated in a single cylinder engine. The test results show that the flash boiling enhances the lean mixture formation, and realizes combustion with low soot and low NOx without EGR (exhaust gas recirculation) while also improving thermal efficiency. An additional test was performed to identify the effects of the flash boiling and the ignition delay, and the results show that the long ignition delay plays the most important role in the thermal efficiency and emission changes and that the flash boiling facilitates the formation of leaner mixtures that lower the overall combustion rate and achieves very low NOx emissions