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Microgravity experiments of flame spread along a fuel droplet array were performed to examine the effect of ambient pressure on the flame spread speed. The purpose of this research is to investigate growth mechanism of group combustion of fuel droplets. A fuel droplet array was suspended by SiC fibers of 14 μm in diameter. The number of fuel droplet was varied from 6 to 10 depending on the droplet spacing. Nondimensional droplet spacing and ambient pressure were varied from 2 to 12.5 and from 0.10 to 0.60 MPa, respectively. To simulate flame spread through a 3D fuel-droplet-matrix, a fuel droplet array was placed on the axis of a rectangular optical cell. n-decane was employed as a fuel. The normalized flame spread speed decreased as the ambient pressure increased. For all ambient pressures, the normalized flame spread speed takes the maximum between 3 and 3.75 in the nondimensional droplet spacing. The dependence of the normalized flame spread speed on ambient pressure increases with the increase in the nondimensional droplet spacing. An empirical model equation which expresses the dependence of flame spread speed on the ambient pressure was proposed.

A lab-scale two-stage light-oil burner has been developed to obtain the fundamental data required for designing burners to heat a diesel particulate filter when exhaust gas temperature of the main engine is low. Regenerative-heating and pre-evaporation premixing combustion were adopted to this burner for downsizing and reducing cost. Two-stage combustion was realized in the burner to reduce the heat-load of the combustion chamber for the first stage combustion. The combustion chamber volume is about 66 mL. Observations of flame-holding condition and temperature measurements of the burner and combustion gas were performed with varying the fuel flow rate and air flow rate. Three types of secondary air nozzle and three secondary air nozzle positions were tested to understand the effect of the secondary nozzle on combustion gas temperature and combustion gas compositions. It was found that the burner in the single-stage combustion mode was able to stabilize a flame in the range of 2 to 14 mL/min in fuel flow rate at adequate equivalence ratio in the range of 1.4 to 1.8. Combustion gas temperature of the burner in the two-stage combustion mode is determined by the total equivalence ration and is independent on the equivalence ratio of the first stage combustion. It is possible to suppress CO and NOx emissions when the burner is operated at 0.8 in the total equivalence ratio.

Histamine is a biological amine that functions as a neurotransmitter in the brain to regulate arousal, appetite, and cognitive functions. Many pharmacological studies using histamine receptor agonists and antagonists have found that histamine promotes memory consolidation and retrieval. More recently, we have revealed that the activation of the brain histaminergic system by H3R antagonists/inverse agonists restores retrieval of forgotten long- term memory in mice and humans. The recovery of memory retrieval may involve histamine-induced excitatory effects. Histamine may increase neuronal excitability throughout the neural circuit, including both neurons that are and are not recruited into the memory trace, similar to noise added to the neural circuits for memory retrieval. Stochastic resonance can explain how adding noise to the circuit enhances memory retrieval. Memory is processed not only by consolidation and retrieval, but also by various processes such as maintenance, reconsolidation, extinction, and reinstatement. Further studies that separately analyze the memory processes are needed to elucidate the whole picture of the effects of histamine on learning and memory. Regarding the human histaminergic system, alterations in histamine signaling have been reported in several neuropsychiatric disorders, and these changes have been suggested to be involved in cognitive dysfunction in patients with the neuropsychiatric disorders. Therefore, the drugs that modulate histamine signaling, including H3R antagonists/inverse agonists, may be effective in the treatment of cognitive dysfunction, including Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Laboratory work is an essential part of natural science education because it provides students with a valuable opportunity to experience practical scientific research firsthand. In laboratory work in pharmacology, students generally learn about biological mechanisms and drug action mechanisms by analyzing drug actions using laboratory animals. Actual experience with hands and eyes is an important factor in the laboratory work. Under the COVID-19 epidemic, however, we were forced to conduct the laboratory work online. For the laboratory work using isolated organs, we used simulation software, in which students can examine effects of a range of drugs on the smooth muscle within the guinea pig ileum. For the behavioral observation practice, we showed the video of the experiments conducted by the instructors beforehand to the students, and asked them to observe and analyze the behavior. In this review, we will share our challenges to online laboratory work. [ABSTRACT FROM AUTHOR]