A questionnaire survey of the illegal importation of pork products by air travelers into Japan from China and exploration of causal factors.

With the aim of obtaining information to establish an import risk assessment on African swine fever (ASF) and other transboundary animal diseases (TADs) into Japan, a questionnaire survey was conducted between 1 August and 20 September 2019 on air travellers arriving into Japan from China. There were 248 responses with 2.8 % of respondents illegally importing pork products. The quantity imported per traveller varied between 250 g and 2 kg. Concerning the travellers' perception in regard to the difficulty of importing a pork product in their luggage, 32 respondents (12.9 %) considered it very easy or rather easy and 216 (87.1 %) very difficult or rather difficult. In regard to the recognition of respondents of the illegality of importing pork products into Japan, seven respondents (2.8 %) did not consider this practice to be illegal whilst 241 (97.2 %) had some idea of the illegal nature of this behaviour. The regression analysis revealed that the practice of illegal importation of pork products was significantly affected by the level of difficulty perception held by the traveller (P < 0.001) and that the difficulty perception is significantly affected by the level of recognition of illegality by the traveller (P < 0.001). The result of this study will not only provide useful data in developing a model to assess the probability of introduction of ASF and other TADs into Japan and other countries, but also in monitoring the effect of measures taken by the government to reduce the illegal importation of meat and meat products.

Selective Formation of Zigzag Edges in Graphene Cracks.

We report the thermally induced unconventional cracking of graphene to generate zigzag edges. This crystallography-selective cracking was observed for as-grown graphene films immediately following the cooling process subsequent to chemical vapor deposition (CVD) on Cu foil. Results from Raman spectroscopy show that the crack-derived edges have smoother zigzag edges than the chemically formed grain edges of CVD graphene. Using these cracks as nanogaps, we were also able to demonstrate the carrier tuning of graphene through the electric field effect. Statistical analysis of visual observations indicated that the crack formation results from uniaxial tension imparted by the Cu substrates together with the stress concentration at notches in the polycrystalline graphene films. On the basis of simulation results using a simplified thermal shrinkage model, we propose that the cooling-induced tension is derived from the transient lattice expansion of narrow Cu grains imparted by the thermal shrinkage of adjacent Cu grains.

Fabrication and optical probing of highly extended, ultrathin graphene nanoribbons in carbon nanotubes.

Nanotemplated growth of graphene nanoribbons (GNRs) inside carbon nanotubes is a promising mean to fabricate ultrathin ribbons with desired side edge configuration. We report the optical properties of the GNRs formed in single-wall carbon nanotubes. When coronene is used as the precursor, extended GNRs are grown via a high-temperature annealing at 700 °C. Their optical responses are probed through the diazonium-based side-wall functionalization, which effectively suppresses the excitonic absorption peaks of the nanotubes without damaging the inner GNRs. Differential absorption spectra clearly show two distinct peaks around 1.5 and 3.4 eV. These peaks are assigned to the optical transitions between the van Hove singularities in the density of state of the GNRs in qualitative agreement with the first-principles calculations. Resonance Raman spectra and transmission electron microscope observations also support the formation of long GNRs.

Green odor and depressive-like state in rats: toward an evidence-based alternative medicine?

It is widely accepted that mental stress is an important factor in the development of psychological disorders such as depression. On pre-existing evidence, the so-called green odor may have a relieving and sedative effect on animals exposed to stressful situations. Using two behavioral models of depression, the forced-swim test and learned helplessness paradigm, we investigated whether inhalation of green odor (a 50:50 mixture of trans-2-hexenal and cis-3-hexenol) might alleviate and/or prevent experimentally induced depressive-like states in rats. A 3-min swim every day for 7 days resulted in significant prolongation of immobility time (vs. day 1). Inhaling green odor, but not vehicle, thereafter for 10 days (without swimming) led to the prolonged immobility time being significantly reduced and the hippocampal level of brain-derived neurotrophic factor (BDNF) being significantly increased. In the learned helplessness paradigm, the failure number and time spent in the shock compartment seen in the active avoidance test were both significantly attenuated in those rats that inhaled green odor for 11 days after the postshock screening test (vs. vehicle-exposed rats). Finally, for 10 consecutive days rats continuously exposed to green odor or vehicle swam for 3 min/day. Immobility time was significantly shorter in the green-odor group than in the vehicle-exposed group on days 6-10. These results suggest that green odor has not only a therapeutic, but also a preventive effect on depressive-like states in rats. These effects may be at least in part due to a green odor-induced upregulation of BDNF in the hippocampus.

Solution-phase extraction of ultrathin inner shells from double-wall carbon nanotubes.

We present an efficient method to extract inner shells of double-wall carbon nanotubes (DWCNTs) in liquid phase. The extraction of inner from outer shells is achieved by cutting the DWCNTs with vigorous sonication in water containing surfactants. The extracted shells are perfectly isolated single-wall carbon nanotubes (SWCNTs) and can be separated using density gradient ultracentrifugation. Statistical analysis using high-resolution transmission electron microscopy reveals that the enrichment of SWCNTs with narrow diameter (0.62-1.0 nm) up to 100% is achieved from highly pure DWCNTs. Furthermore, the (5,4) SWCNTs, which have the diameter of 0.62 nm, are concentrated. Our findings provide a novel way to obtain very narrow, highly isolated SWCNTs with ultraclean surface that have not been obtained in conventional synthesis methods.