Examination of VOC Concentration of Aroma Essential Oils and Their Major VOCs Diffused in Room Air.

This study analyzed temporal variation of the composition of volatile organic compounds (VOCs) at different diffusion time of gaseous phase of aroma compounds of four essential oils, lavender, tea tree, eucalyptus, and melissa. GC/MS methodology with the trace gas sampling by a thermal desorption tube is used to quantitatively determine the concentration of the corresponding 14 kinds of major and original VOCs in four essential oils. This study revealed for the first time that the concentration level of gaseous phase composition is varied, with a diffusion time from that of the liquid phase at equilibrium with it and the VOCs in the essential oils are classified into two groups, depending on whether their concentration with the time. It is verified that the total concentration of VOCs of these essential oils in the room air diffused by the ultrasonic diffuser is as low as 0.6 ppb and decreased soon below 0.1 ppb.

Source analysis of stimulus-preceding negativity constrained by functional magnetic resonance imaging.

The stimulus-preceding negativity (SPN) is an event-related potential (ERP) reflecting anticipation. The anterior insular cortex is assumed to be one of the physiological sources of the SPN. However, the precise neural substrates of the SPN have yet to be confirmed. We therefore performed separate functional magnetic resonance imaging (fMRI) and ERP studies using the same time estimation task, followed by fMRI-constrained ERP source analysis. Dipole locations were determined by the fMRI results, while the time courses of dipole activities were modeled by the ERP data. Analysis revealed that the right anterior insula was significantly activated before delivery of the feedback stimulus, whereas the left anterior insula was not, and that the SPN mainly arose from four groups of brain regions related to, respectively: (1) the salience network, (2) reward expectation, (3) perceptual anticipation, and (4) arousal. The results suggest that the SPN pertains to multiple brain functions with complex interactions.

Facial, verbal, and symbolic stimuli differently affect the right hemisphere preponderance of stimulus-preceding negativity.

The present study investigated whether the right hemisphere preponderance of stimulus-preceding negativity (SPN) was affected by different categories of visual feedback stimulus. A time estimation task was performed with facial, verbal, symbolic, and no-feedback conditions. A principal component analysis identified an early component of SPN in addition to a late component that was morphologically similar to the original SPN. Motivational scores in the verbal and facial conditions were higher than that in the symbolic condition. Significant right hemisphere preponderance of the late SPN was observed in the symbolic condition but not in the verbal condition, whereas right hemisphere preponderance of the early SPN was observed in the facial condition. The right hemisphere preponderance was influenced by the category of visual feedback stimulus through stimulus-related activation and the effect of the motivational level.

Cloning of a novel dehalogenase from environmental DNA.

Cloning of pceA, the gene of tetrachloroethene (PCE)-reductive dehalogenase, was undertaken from environmental DNA. Two genes were amplified using PCR primer deduced from pceA. Functional expression of these genes was unsuccessful in Escherichia coli, but PceA1 synthesized in vitro was enzymatically active. In recombinant E. coli, PceA1 formed a complex with host DnaK and caused filamentous growth.