This paper describes a model of electron energization and cyclotron-maser emission applicable to astrophysical magnetized collisionless shocks. It is motivated by the work of Begelman, Ergun and Rees [Astrophys. J. 625, 51 (2005)] who argued that the cyclotron-maser instability occurs in localized magnetized collisionless shocks such as those expected in blazar jets. We report on recent research carried out to investigate electron acceleration at collisionless shocks and maser radiation associated with the accelerated electrons. We describe how electrons accelerated by lower-hybrid waves at collisionless shocks generate cyclotron-maser radiation when the accelerated electrons move into regions of stronger magnetic fields. The electrons are accelerated along the magnetic field and magnetically compressed leading to the formation of an electron velocity distribution having a horseshoe shape due to conservation of the electron magnetic moment. Under certain conditions the horseshoe electron velocity distribution function is unstable to the cyclotron-maser instability [Bingham and Cairns, Phys. Plasmas 7, 3089 (2000); Melrose, Rev. Mod. Plasma Phys. 1, 5 (2017)].

To characterise the dissemination patterns of uropathogenic Escherichia coli (UPEC) in a community, we conducted a study utilising molecular and fundamental descriptive epidemiology. The subjects, consisted of women having community-acquired acute urinary tract infection (UTI), were enrolled in the study from 2011 to 2012. UPEC isolates were subjected to antibacterial-susceptibility testing, O serogrouping, phylotyping, multilocus-sequence typing with phylogenetic-tree analysis and pulsed-field-gel electrophoresis (PFGE). From the 209 unique positive urinary samples 166 UPEC were isolated, of which 129 were fully susceptible to the tested antibiotics. Of the 53 sequence types (STs), the four most prevalent STs (ST95, ST131, ST73 and ST357) accounted for 60% of all UPEC strains. Antimicrobial resistance was less frequently observed for ST95 and ST73 than for the others. A majority of rare STs and a few common STs constituted the diversity pattern within the population structure, which was composed of the two phylogenetically distinct clades. Eleven genetically closely related groups were determined by PFGE, which accounted for 42 of the 166 UPEC isolates, without overt geo-temporal clustering. Our results indicate that a few major lineages of UPEC, selected by unidentified factors, are disseminated in this community and contribute to a large fraction of acute UTIs.

Pneumococcal serotype replacement is an important issue after the introduction of pneumococcal conjugate vaccine (PCV) in children. After the introduction of 13-valent PCV, the incidence of invasive pneumococcal diseases (IPD) caused by Streptococcus pneumoniae serotype 12F (Sp12F) have increased in some countries; however, an outbreak of Sp12F has not reported in the post-13-valent PCV era. We experienced a local outbreak of Sp12F during March through May 2016 in Tsuruoka city, Japan after the introduction of 13-valent PCV in 2013. The IPD patients were two children and seven adults, three of whom died with a rapid disease progress. Although the clear transmission route was not determined, eight of the nine patients (89%) had close contact with children, which suggests that transmitted colonisation of Sp12F among children and adults might be the source of transmission. Continuous monitoring of IPDs, along with the determination of pneumococcal serotypes, is warranted in the post–13-valent PCV era. New IPD control strategies may be needed if this fatal outbreak continues to occur.

The influence of a strong external magnetic field on the collimation of a high Mach number plasma flow and its collision with a solid obstacle is investigated experimentally and numerically. The laser irradiation ( $I\sim 2\times 10^{14}~\text{W}\cdot \text{cm}^{-2}$ ) of a multilayer target generates a shock wave that produces a rear side plasma expanding flow. Immersed in a homogeneous 10 T external magnetic field, this plasma flow propagates in vacuum and impacts an obstacle located a few mm from the main target. A reverse shock is then formed with typical velocities of the order of 15–20 $\pm$ 5 km/s. The experimental results are compared with 2D radiative magnetohydrodynamic simulations using the FLASH code. This platform allows investigating the dynamics of reverse shock, mimicking the processes occurring in a cataclysmic variable of polar type.

A new target design is presented to model high-energy radiative accretion shocks in polars. In this paper, we present the experimental results obtained on the GEKKO XII laser facility for the POLAR project. The experimental results are compared with 2D FCI2 simulations to characterize the dynamics and the structure of plasma flow before and after the collision. The good agreement between simulations and experimental data confirms the formation of a reverse shock where cooling losses start modifying the post-shock region. With the multi-material structure of the target, a hydrodynamic collimation is exhibited and a radiative structure coupled with the reverse shock is highlighted in both experimental data and simulations. The flexibility of the laser energy produced on GEKKO XII allowed us to produce high-velocity flows and study new and interesting radiation hydrodynamic regimes between those obtained on the LULI2000 and Orion laser facilities.

In this paper, we present a model characterizing the interaction of a radiative shock (RS) with a solid material, as described in a recent paper (Koenig et al., Phys. Plasmas, 24, 082707 (2017)), the new model is then related to recent experiments performed on the GEKKO XII laser facility. The RS generated in a xenon gas cell propagates towards a solid obstacle that is ablated by radiation coming from the shock front and the radiative precursor, mimicking processes occurring in astrophysical phenomena. The model presented here calculates the dynamics of the obstacle expansion, which depends on several parameters, notably the geometry and the temperature of the shock. All parameters required for the model have been obtained from experiments. Good agreement between experimental data and the model is found when spherical geometry is taken into account. As a consequence, this model is a useful and easy tool to infer parameters from experimental data (such as the shock temperature), and also to design future experiments.

Hospital-based surveillance was conducted at two widely separated regions in Myanmar during the 2015 dengue epidemic. Acute phase serum samples were collected from 332 clinically diagnosed dengue patients during the peak season of dengue cases. Viremia levels were measured by quantitative real-time PCR and plaque assays using FcγRIIA-expressing and non-FcγRIIA-expressing BHK cells to specifically determine the infectious virus particles. By serology and molecular techniques, 280/332 (84·3%) were confirmed as dengue patients. All four serotypes of dengue virus (DENV) were isolated from among 104 laboratory-confirmed patients including two cases infected with two DENV serotypes. High percentage of primary infection was noted among the severe dengue patients. Patients with primary infection or DENV IgM negative demonstrated significantly higher viral loads but there was no significant difference among the severity groups. Viremia levels among dengue patients were notably high for a long period which was assumed to support the spread of the virus by the mosquito vector during epidemic. Phylogenetic analyses of the envelope gene of the epidemic strains revealed close similarity with the strains previously isolated in Myanmar and neighboring countries. DENV-1 dominated the epidemic in 2015 and the serotype (except DENV-3) and genotype distributions were similar in both study sites.

Chikungunya virus (CHIKV) and Ross River virus (RRV) of the genus Alphavirus, family Togaviridae are mainly transmitted by Aedes mosquitoes and the symptoms they cause in patients are similar to dengue. A chikungunya (CHIK) outbreak re-emerged in several Asian countries during 2005–2006. This study aimed to clarify the prevalence of CHIKV infection in suspected dengue patients in six countries in South Asia and Southeast Asia. Seven hundred forty-eight serum samples were from dengue-suspected patients in South Asia and Southeast Asia, and 52 were from patients in Fiji. The samples were analysed by CHIKV IgM capture ELISA, CHIKV IgG indirect ELISA and focus reduction neutralization test against CHIKV or RRV. CHIK-confirmed cases in South Asia, particularly Myanmar and Sri Lanka, were 4·6%, and 6·1%, respectively; and in Southeast Asia, particularly Indonesia, the Philippines and Vietnam, were 27·4%, 26·8% and 25·0%, respectively. It suggests that CHIK was widely spread in these five countries in Asia. In Fiji, no CHIK cases were confirmed; however, RRV-confirmed cases represented 53·6% of suspected dengue cases. It suggests that RRV is being maintained or occasionally entering from neighbouring countries and should be considered when determining a causative agent for dengue-like illness in Fiji.

Although outbreaks of acute respiratory infection (ARI) at shelters are hypothesized to be associated with shelter crowding, no studies have examined this relationship. We conducted a retrospective study by reviewing medical records of evacuees presenting to one of the 37 clinics at the shelters in Ishinomaki city, Japan, during the 3-week period after the Great Eastern Japan Earthquake and tsunami in 2011. On the basis of a locally weighted scatter-plot smoothing technique, we categorized 37 shelters into crowded (mean space <5·5 m2/per person) and non-crowded (⩾5·5 m2) shelters. Outcomes of interest were the cumulative and daily incidence rate of ARI/10 000 evacuees at each shelter. We found that the crowded shelters had a higher median cumulative incidence rate of ARI [5·4/10 000 person-days, interquartile range (IQR) 0–24·6, P = 0·04] compared to the non-crowded shelters (3·5/10 000 person-days, IQR 0–8·7) using Mann–Whitney U test. Similarly, the crowded shelters had an increased daily incidence rate of ARI of 19·1/10 000 person-days (95% confidence interval 5·9–32·4, P < 0·01) compared to the non-crowded shelters using quasi-least squares method. In sum, shelter crowding was associated with an increased incidence rate of ARI after the natural disaster.

In 2013, an unusual increase of paratyphoid fever cases in travellers returning from Cambodia was reported in Japan. From December 2012 to September 2013, 18 cases of Salmonella Paratyphi A infection were identified. Microbiological analyses revealed that most isolates had the same clonal identity, although the epidemiological link between these cases remains unclear. It was inferred that the outbreak was caused by a common and persistent source in Cambodia that was likely to have continued during 2014. The information of surveillance and laboratory data from cases arising in travellers from countries with limited surveillance systems should be timely shared with the country of origin.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

The phage types and antimicrobial susceptibilities of 226 isolates of Salmonella enterica serovar Typhi from imported cases in Japan between 2001 and 2006 were investigated. Most (93·8%) had travelled to Asian countries, particularly South East Asia. Twenty-one phage types were identified with E1 (30·5%), UVS (15·9%) and B1 (9·3%) being the most common. The frequency of multidrug-resistant strains reached 37·0% in 2006 with phage types E1 and E9 predominating. Almost half (48·2%) of the isolates were resistant to nalidixic acid and two isolates displayed high-level fluoroquinolone resistance. Three mutations, two in gyrA and one in parC, were identified in both isolates.

Rates of occurrence and degrees of imposex, and tissue concentrations of organotin compounds (tributyltin, TBT; dibutyltin, DBT; butyltin, MBT; triphenyltin, TPT; diphenyltin, DPT; and phenyltin, MPT) in the rock shell, Thais clavigera and T. bronni (Mollusca: Gastropoda) were investigated at 32 sites in Japan from May 1990 to October 1992. The rate of occurrence of imposex was 100% in both species, at almost all sites surveyed. Degrees of imposex indicated by relative penis length (RPL) index reflected the pollution levels not only of TBT, but also TPT. In heavily polluted areas, many individuals were found with oviducts which were blocked by vas deferens development, and capsule glands which were filled with aborted egg masses. These organisms were thought to be sterile.

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

National Research Institute of Fisheries Science (NRIFS) has carried out the long term monitoring program for radioactive pollution in marine organisms caught around Japan in order to confirm the safety of marine organisms as food source. Recently, the effective ecological half-lives have been introduced to estimate the recovery time from radioactive pollution. In this study, the effective ecological half-lives of Cs-137 for some fishes were calculated from our monitoring data. It is known that fish species have each effective ecological half-lives. However, it has been unclear what change these half-lives of Cs-137 for fishes. Fishes intake Cs-137 through food chain and directly from their surrounding seawater. Therefore, the effective ecological half-lives of Cs-137 for some fishes would be controlled by the effective environment half-lives of Cs-137 for their surrounding seawater. There is difference in the effective environment half-lives between the open ocean and the coastal seawaters. Some fishes move between the open ocean and the coastal areas, and therefore their effective ecological half-lives are influenced by the effective environment half-lives for seawaters of both areas. Consequently, the rate of the influence by seawater in each area would produce the differences in the effective ecological half-lives among fish species.

Japanese Black cattle (Wagyu), deposit much higher amounts of intramuscular fat, known as marbling, than other breeds of cattle. To determine whether this unique fat deposition is attributable to the somatotropic axis, we compared pulsatile growth hormone (GH) secretion, plasma levels of insulin-like growth factor-1 (IGF-1) and cellular density of somatotrophs (GH-expressing cells) in the anterior pituitary glands of Japanese Black and Holstein steers. Blood samples were withdrawn every 15 min for 6 h from 14 Japanese Black and 12 Holstein steers at about 17 months of age, and GH and IGF-1 concentrations were determined. The distribution and proportion of GH-expressing cells were analysed by immunohistochemistry combined with point-count morphometry in pituitaries from six steers from each breed aged about 18 to 21 months. Overall mean and baseline plasma GH concentrations were lower (P < 0·001) in Japanese Black than Holstein steers. In addition, Japanese Black had smaller (P < 0·05) amplitudes of GH secretory pulses than Holstein steers, whereas the GH pulse frequency did not differ between the breeds. Japanese Black steers also had lower (P < 0·001) plasma levels of IGF-1 than Holstein steers. The marbling score of Japanese Black steers was higher (P < 0·001) than that of Holsteins at the same carcass weight. The proportion of GH-expressing cells was smaller (P < 0·05) in Japanese Black than Holstein steers at the hind dorsal and hind ventral regions of the adenohypophysis. Thus, in Japanese Black and Holstein steers, the breed difference in the relative density of GH-expressing cells corresponded to that in profiles of pulsatile GH secretion. These results suggest that the features of the somatotropic axis intrinsically differ between Japanese Black and Holstein cattle and that these features may be partly responsible for the genetic ability of the former to deposit greater amounts of marbling fat and for the smaller frame of Wagyu cattle.