Association between Asian dust exposure and respiratory function in children with bronchial asthma in Nagasaki Prefecture, Japan.

BACKGROUND: Studies on the adverse effects of Asian dust (AD) on respiratory function in children are scarce. The objective of this study was to examine the association between AD and respiratory function by measuring peak expiratory flow rates (PEFRs) in asthmatic children. METHODS: The study was carried out from March to May from 2014 through 2016. One hundred ten children with bronchial asthma were recruited from four hospitals in the Goto Islands and south Nagasaki area in Nagasaki prefecture. The parents were asked to record their children's PEFRs every morning/evening and clinical symptoms in an asthma diary. AD was assessed from light detection and ranging data, and a linear mixed-effects model was used to estimate the effects of AD on daily PEFR. Time-stratified case-crossover analyses were performed to examine the association between AD and asthma attacks defined by reduction levels in PEFR. RESULTS: AD was detected on 11 days in the Goto Islands, and on 23 days in the south Nagasaki area. After adjusting for age, sex, temperature, and daily oxidants, we found a consistent association between AD and a 1.1% to 1.7% decrease in PEFR in the mornings and a 0.7% to 1.3% decrease in the evenings at a lag of 0 to 5 days. AD was not associated with the number of asthma attacks, respiratory symptoms, or other symptoms at any lag days examined. CONCLUSIONS: Exposure to AD was associated with reduced PEFR, although the effects were not large enough to induce clinically apparent symptoms, in clinically well-controlled asthmatic children.

Dose-Dependent Negative Effects of Prior Multiple Vaccinations Against Influenza A and Influenza B Among Schoolchildren: A Study of Kamigoto Island in Japan During the 2011-2012, 2012-2013, and 2013-2014 Influenza Seasons.

Background: We investigated the negative effects of prior multiple vaccinations on influenza vaccine effectiveness (VE) and analyzed the association of VE with prior vaccine doses. Methods: Patients aged 9-18 years presenting with influenza-like illness at a community hospital on a remote Japanese island during the 2011-2012, 2012-2013, and 2013-2014 influenza seasons were tested for influenza using a rapid diagnostic test (RDT). A test-negative, case-control study design was used to estimate the VEs of trivalent inactivated influenza vaccine. Histories of vaccination and medically attended influenza (MA-flu) A and B during 3 previous seasons were collected from registry systems. VE was calculated using multilevel mixed-effects logistic regression models adjusted for the history of RDT-confirmed MA-flu. Results: During 3 influenza seasons, 1668 influenza-like illness episodes were analyzed, including 421 and 358 episodes of MA-fluA and MA-fluB, respectively. The adjusted VE (95% confidence interval) yielded significant dose-dependent attenuations by prior vaccinations against both MA-fluA (0 doses during previous 3 seasons: 96% [69%-100%], 1 dose: 48% [-7% to 74%], 2 doses: 52% [11%-74%], 3 doses: 21% [-25% to 51%]; P for trend < .05) and MA-fluB (0 doses: 66% [-5% to 89%], 1 dose: 48% [-14% to 76%], 2 doses: 34% [-33% to 67%], 3 doses: -7% [-83% to 37%]; P for trend < .05). After excluding episodes of MA-flu during prior 3 seasons, similar trends were observed. Conclusions: Repeated previous vaccinations over multiple seasons had significant dose-dependent negative impacts on VE against both MA-fluA and MA-fluB. Further studies to confirm this finding are necessary.

One year investigation of the prevalence and diversity of clostridial spores in raw milk from the Tokachi area of Hokkaido.

We investigated the seasonal prevalence and diversity of clostridial spores in raw milk from the Tokachi area of Hokkaido. Samples of raw milk were collected quarterly from May 2013 through February 2014. The mean clostridial spore count for the raw milk from 336 milk tankers was 27.6 CFU/100 ml. The clostridial species isolated most frequently from raw milk samples was Clostridium tyrobutyricum. The dominant species was C. tyrobutyricum regardless of the season. The percentage of samples with low spore counts (<10 CFU/100 ml) was highest (60.9%) during winter (February) and lowest (34.5%) in autumn (November). In comparison, the percentage of samples with high spore counts (>100 CFU/100 ml) was highest (5.7%) in autumn (November) and lowest (1.1%) during spring (May).

Negative impact of prior influenza vaccination on current influenza vaccination among people infected and not infected in prior season: A test-negative case-control study in Japan.

BACKGROUND: Accumulating evidences indicate that repeated influenza vaccination has negative impact on the vaccine effectiveness (VE). However no published studies considered past influenza infection when assessing the VE of repeated vaccination. METHODS: Prospective surveillance was conducted from 2009 to 2012 at a community hospital on a small island in Japan. The study included all outpatients with an influenza-like illness (ILI) who attended the hospital, and a rapid diagnostic test (RDT) was used to diagnose influenza A/B infection. The VE of trivalent inactivated influenza vaccine (TIV) against medically attended influenza A (MA-fluA) was estimated using a test-negative case-control study design. The influence of TIV in the prior season on VE in the current season was investigated in the context of MA-fluA during the prior season. RESULTS: During the three influenza seasons, 5838 ILI episodes (4127 subjects) were analysed. Subjects who had an episode of MA-fluA in the prior season were at a significantly lower risk of MA-fluA in the current season (adjusted odds ratio: 0.38, 95% CI: 0.30-0.50). The overall adjusted VE was 28% (95% CI, 14-40). VE was substantially lower in subjects vaccinated in the prior season compared to those who had not been vaccinated in prior season (19%; 95% CI: 0-35 vs 46%; 95% CI: 26-60, test for interaction, P value <0.05). In subjects who did not have MA-fluA in the prior season showed the attenuation of VE due to repeated vaccination (13%; 95% CI: -7 to 30 vs 44%; 95% CI: 24-59, test for interaction, P<0.05). However this effect was not detected in subjects who had contracted MA-fluA in the prior season. CONCLUSIONS: Negative effects of repeated vaccination were significant among those without history of MA-fluA in the prior season.

Photonic crystal directional coupler switch with small switching length and wide bandwidth.

A directional coupler switch structure capable of short switching length and wide bandwidth is proposed. The switching length and bandwidth have a trade-off relationship in conventional directional coupler switches. Dispersion curves that avoid this trade-off are derived, and a two-dimensional photonic crystal structure that achieves these dispersion curves is presented. Numerical calculations show that the switching length of the proposed structure is 7.1% of that for the conventional structure, while the bandwidth is 2.17 times larger.

Development of high resolution Michelson interferometer for stable phase-locked ultrashort pulse pair generation.

We developed a high resolution Michelson interferometer with a two-frequency He-Ne laser positioning system in order to stabilize the relative phase of a pulse pair. The control resolution corresponded to a 12 as time resolution or a phase of 1.5 degrees at 900 nm. This high resolution Michelson interferometer can generate a phase-locked pulse pair either with a specific relative phase such as 0 or pi radians or with an arbitrary phase. Coherent control of an InAs self-assembled quantum dot was demonstrated using the high resolution Michelson interferometer with a microspectroscopy system.