Intense ultraviolet emission from needle-like WO3 nanostructures synthesized by noncatalytic thermal evaporation

Photoluminescence measurements showed that needle-like tungsten oxide nanostructures synthesized at 590°C to 750°C by the thermal evaporation of WO3 nanopowders without the use of a catalyst had an intense near-ultraviolet (NUV) emission band that was different from that of the tungsten oxide nanostructures obtained in other temperature ranges. The intense NUV emission might be due to the localized states associated with oxygen vacancies and surface states

Programmable spectral shaping to improve the measurement precision of frequency comb mode-resolved spectral interferometric ranging

Comb-mode resolved spectral domain interferometry (CORE-SDI), which is capable of measuring length of kilometers or more with precision on the order of nanometers, is considered to be a promising technology for next-generation length standards, replacing laser displacement interferometers. In this study, we aim to improve the measurement precision of CORE-SDI using programmable spectral shaping. We report the generation of effectively broad and symmetric light sources through the programmable spectral shaping. The light source used here was generated by the spectrally-broadened electro-optic comb with a repetition rate of 17.5 GHz. Through the programmable spectral shaping, the optical spectrum was flattened within 1 dB, resulting in a square-shaped optical spectrum. As a result, the 3-dB spectral width was extended from 1.15 THz to 6.7 THz. We performed a comparison between the measurement results of various spectrum shapes. We confirmed an improvement in the measurement precision from 69 nm to 6 nm, which was also corroborated by numerical simulations. We believe that this study on enhancing the measurement precision of CORE-SDI through the proposed spectral shaping will make a significant contribution to reducing the measurement uncertainty of future CORE-SDI systems, thereby advancing the development of next-generation length standards.Comment: 22 pages, 10 figure

Public-Good Nature of Environmental Conflicts : Individual and Collective Litigations

In environmental conflicts where private citizens sue a polluter, a private citizens participation in the fight for environmental damages is characterized by the public good nature. We examine how the introduction of collective litigation and asymmetric reimbursement rule affects each citizen's choice between free-riding and participation in the collective litigation. Following a Stackelberg model, we assume that citizens move first and the firm follows, while each citizen has to state his environmental damages to the court in the process. Important findings are as follows: First, in the individual litigation, the hungriest citizen who most highly values environmental damages is the only one to participate. Second, in the collective litigation, all citizens participate, provided the total damages of the citizens' group are sufficiently larger than the damages of the hungriest citizen. Third, under certain conditions, introduction of the asymmetric reimbursement rule enhances the possibility that all citizens participate in the collective litigation

Emerging respiratory infections threatening public health in the Asia-Pacific region: a position paper of the Asian Pacific Society of Respirology

In past decades, we have seen several epidemics of respiratory infections from newly emerging viruses, most of which originated in animals. These emerging infections, including severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and the pandemic influenza A(H1N1) and avian influenza (AI) viruses, have seriously threatened global health and the economy. In particular, MERS-CoV and AI A(H7N9) are still causing infections in several areas, and some clustering of cases of A(H5N1) and A(H7N9) may imply future possible pandemics. Additionally, given the inappropriate use of antibiotics and international travel, the spread of carbapenem-resistant Gram-negative bacteria is also a significant concern. These infections with epidemic or pandemic potential present a persistent threat to public health and a huge burden on healthcare services in the Asia-Pacific region. Therefore, to enable efficient infection prevention and control, more effective international surveillance and collaboration systems, in the context of the ‘One Health’ approach, are necessary

Improved production of docosahexaenoic acid in batch fermentation by newly-isolated strains of Schizochytrium sp. and Thraustochytriidae sp. through bioprocess optimization

Thraustochytrids, rich in docosahexaenoic acid (DHA, C22:6??3), represent a potential source of dietary fatty acids. Yet, the effect of culture conditions on growth and fatty acid composition vary widely among different thraustochytrid strains. Two different thraustochytrid strains, Schizochytrium sp. PKU#Mn4 and Thraustochytriidae sp. PKU#Mn16 were studied for their growth and DHA production characteristics under various culture conditions. Although they exhibited similar fatty acid profiles, PKU#Mn4 seemed a good candidate for industrial DHA fermentation while PKU#Mn16 displayed growth tolerance to a wide range of process conditions. Relative DHA content of 48.5% and 49.2% (relative to total fatty acids), respectively, were achieved on glycerol under their optimal flask culture conditions. Maximum DHA yield (Yp/x) of 21.0% and 18.9% and productivity of 27.6 mg/L-h and 31.9 mg/L-h were obtained, respectively, in 5-L bioreactor fermentation operated with optimal conditions and dual oxygen control strategy. A 3.4- and 2.8-fold improvement of DHA production (g/L), respectively, was achieved in this study. Overall, our study provides the potential of two thraustochytrid strains and their culture conditions for efficient production of DHA-rich oil