As a typical plasma-based optical element that can sustain ultra-high light intensity, plasma density gratings driven by intense laser pulses have been extensively studied for wide applications. Here, we show that the plasma density grating driven by two intersecting driver laser pulses is not only nonuniform in space but also varies over time. Consequently, the probe laser pulse that passes through such a dynamic plasma density grating will be depolarized, that is, its polarization becomes spatially and temporally variable. More importantly, the laser depolarization may spontaneously take place for crossed laser beams if their polarization angles are arranged properly. The laser depolarization by a dynamic plasma density grating may find application in mitigating parametric instabilities in laser-driven inertial confinement fusion.

We report the experimental results of the commissioning phase in the 10 PW laser beamline of the Shanghai Superintense Ultrafast Laser Facility (SULF). The peak power reaches 2.4 PW on target without the last amplifying during the experiment. The laser energy of 72 ± 9 J is directed to a focal spot of approximately 6 μm diameter (full width at half maximum) in 30 fs pulse duration, yielding a focused peak intensity around 2.0 × 1021 W/cm2. The first laser-proton acceleration experiment is performed using plain copper and plastic targets. High-energy proton beams with maximum cut-off energy up to 62.5 MeV are achieved using copper foils at the optimum target thickness of 4 μm via target normal sheath acceleration. For plastic targets of tens of nanometers thick, the proton cut-off energy is approximately 20 MeV, showing ring-like or filamented density distributions. These experimental results reflect the capabilities of the SULF-10 PW beamline, for example, both ultrahigh intensity and relatively good beam contrast. Further optimization for these key parameters is underway, where peak laser intensities of 1022–1023 W/cm2 are anticipated to support various experiments on extreme field physics.

We report on experimental observation of non-laminar proton acceleration modulated by a strong magnetic field in laser irradiating micrometer aluminum targets. The results illustrate the coexistence of ring-like and filamentation structures. We implement the knife edge method into the radiochromic film detector to map the accelerated beams, measuring a source size of 30–110 μm for protons of more than 5 MeV. The diagnosis reveals that the ring-like profile originates from low-energy protons far off the axis whereas the filamentation is from the near-axis high-energy protons, exhibiting non-laminar features. Particle-in-cell simulations reproduced the experimental results, showing that the short-term magnetic turbulence via Weibel instability and the long-term quasi-static annular magnetic field by the streaming electric current account for the measured beam profile. Our work provides direct mapping of laser-driven proton sources in the space-energy domain and reveals the non-laminar beam evolution at featured time scales.

Klebsiella pneumoniae is a common pathogen associated with nosocomial infections and is characterised serologically by capsular polysaccharide (K) and lipopolysaccharide O antigens. We surveyed a total of 348 non-duplicate K. pneumoniae clinical isolates collected over a 1-year period in a tertiary care hospital, and determined their O and K serotypes by sequencing of the wbb Y and wzi gene loci, respectively. Isolates were also screened for antimicrobial resistance and hypervirulent phenotypes; 94 (27.0%) were identified as carbapenem-resistant (CRKP) and 110 (31.6%) as hypervirulent (hvKP). isolates fell into 58 K, and six O types, with 92.0% and 94.2% typeability, respectively. The predominant K types were K14K64 (16.38%), K1 (14.66%), K2 (8.05%) and K57 (5.46%), while O1 (46%), O2a (27.9%) and O3 (11.8%) were the most common. CRKP and hvKP strains had different serotype distributions with O2a:K14K64 (41.0%) being the most frequent among CRKP, and O1:K1 (26.4%) and O1:K2 (17.3%) among hvKP strains. Serotyping by gene sequencing proved to be a useful tool to inform the clinical epidemiology of K. pneumoniae infections and provides valuable data relevant to vaccine design.

Longan County is considered a highly endemic area for hepatitis B virus (HBV). The plasma-derived vaccine has been used in newborns in this area since 1987. A cross-sectional survey was conducted to evaluate the long-term effectiveness of this vaccine. In total, 1634 participants born during 1987–1993 and who had received a series of plasma-derived HB vaccinations at ages 0, 1, and 6 months were enrolled. Serological HBV markers were detected and compared with previous survey data. Overall the prevalence of hepatitis B surface antigen (HBsAg) in all participants was 3·79%; 3·47% of subjects who had received the first dose within 24 h were HBsAg positive, and 8·41% of subjects who had received a delayed first dose were also HBsAg positive. There were 1527 subjects identified who had received the first dose within 24 h and whose HBsAg and anti-HBc prevalence increased yearly after immunization, while the anti-HBs-positive rate and vaccine effectiveness declined. The geometric mean concentration of antibody in the anti-HB-positive participants was 55·13 mIU/ml and this declined after immunization. Fewer than 2·0% of participants had anti-HB levels ⩾1000 mIU/ml. The data show that the protective efficacy of the plasma-derived vaccinations declined and administration of HB vaccine within 24 h of birth was very important. To reduce the risk of HBV infection in this highly endemic area, a booster dose might be necessary if anti-HBs levels fall below 10 mIU/ml after age 18 years. Furthermore, studies on the immune memory induced by plasma-derived HB vaccine are needed.

Pulsed tandem gas metal arc welding (PT-GMAW) is being developed to increase productivity and minimise weld-induced distortion in ship-building. The PT-GMAW process was used in pulse–pulse mode to butt-weld two different strength and thickness steels; the residual stress and hardness profiles of the welds are reported and correlated.

The effects of ion motion on the generation of short-cycle relativistic laser pulses during radiation pressure acceleration are investigated by analytical modeling and particle-in-cell simulations. Studies show that the rear part of the transmitted pulse modulated by ion motion is sharper compared with the case of the electron shutter only. In this study, the ions further modulate the short-cycle pulses transmitted. A 3.9 fs laser pulse with an intensity of $1.33\times 10^{21}\ {\rm W}\ {\rm cm}^{-2}$ is generated by properly controlling the motions of the electron and ion in the simulations. The short-cycle laser pulse source proposed can be applied in the generation of single attosecond pulses and electron acceleration in a small bubble regime.

The survival behaviour of Vibrio cholerae in cholera epidemics, together with its attributes of virulence-associated genes and molecular fingerprints, are significant for managing cholera epidemics. Here, we selected five strains representative of V. cholerae O1 and O139 involved in cholera events, examined their survival capacity in large volumes of water sampled from epidemic sites of a 2005 cholera outbreak, and determined virulence-associated genes and molecular subtype changes of the surviving isolates recovered. The five strains exhibited different survival capacities varying from 17 to 38 days. The virulence-associated genes of the surviving isolates remained unchanged, while their pulsotypes underwent slight variation. In particular, one waterway-isolated strain maintained virulence-associated genes and evolved to share the same pulsotype as patient strains, highlighting its role in the cholera outbreak. The strong survival capacity and molecular attributes of V. cholerae might account for its persistence in environmental waters and the long duration of the cholera outbreak, allowing effective control measures.

The density distribution of inhomogeneous dense deuterium-tritium plasmas in laser fusion is revealed by the energy loss of fast protons going through the plasma. In our simulation of a plasma density diagnostics, the fast protons used for the diagnostics may be generated in the laser-plasma interaction. Dividing a two-dimensional area into grids and knowing the initial and final energies of the protons, we can obtain a large linear and ill-posed equation set for the densities of all grids, which is solved with the Tikhonov regularization method. We find that the accuracy of the set plan with four proton sources is better than those of the set plans with less than four proton sources. Also we have done the density reconstruction especially for four proton sources with and without assuming circularly symmetrical density distribution, and find that the accuracy is better for the reconstruction assuming circular symmetry. The error is about 9% when no noise is added to the final energy for the reconstruction of four proton sources assuming circular symmetry. The accuracies for different random noises to final proton energies with four proton sources are also calculated.

Hepatitis E virus (HEV) is a zoonotic pathogen of which several species of animals are considered to be reservoirs. Thirty-eight faecal samples, obtained from 22 species of animals including birds in a wildlife first-aid centre in Eastern China, were tested for HEV RNA. Our survey revealed that in total 28·9% (95% confidence interval 14·5–43·4) of the faecal samples from various mammals and birds were HEV RNA positive. Sequence and phylogenetic analyses of the 11 isolates demonstrated that all sequences clustered in genotype 4 with 96–100% identity to each other. In addition, serum samples from seven animal handlers have shown that five (71·4%) were seropositive. The findings imply that cross-species infection of HEV had probably occurred in this zoo-like location, and moreover, birds can be infected naturally with mammalian HEV.

The polynomial-fit method is applied to remove the uneven background of a satellite when it is near a bright primary object. Detailed analysis of this method is given. Some useful conclusions are drawn from the results of simulated data.

This paper reports on our observing campaign of faint satellites performed at the National Time Service Center and Sheshan station of SHAO from 1994 up to today. In the past few years due to benefit from using a large size CCD and the publication of the modern catalogues (UCAC2), a series of observations of faint satellites were obtained by us. Moreover the work of improving the orbit of Phoebe via numerical fit to the observations over a century is also presented.

Thelazia callipaeda, commonly known as the ‘oriental eyeworm’, has been recently reported in Italy and other European countries. The insect/s that act as intermediate hosts and details of larval development inside the vector remain unclear. In order to (1) demonstrate the species of fly that may act as vector/s for T. callipaeda in southern Italy (Site A) and China (Site B) and (2) describe the larval development of the nematode in the body of flies, 847 Phortica (Drosophilidae) flies were collected from the above two sites, each with a history of human and/or canine thelaziosis. Flies were identified as Phortica variegata (245 – site A) and Phortica okadai (602 – site B), experimentally infected by 1st-stage larvae (L1), kept at different temperatures and dissected daily until day 180 post-infection (p.i.). Dead flies from site A were subjected to specific polymerase chain reaction (PCR) assay to detect T. callipaeda. To demonstrate the role of Phortica as vectors of T. callipaeda, 3rd-stage larvae (L3) recovered from the proboscis of flies were deposited onto the cornea of the eyes of dogs and rabbits. Following dissection, 3 (2·9%) of P. variegata in site A were found to be infected by L3 in the proboscis on days +14, +21 and +53 p.i., compared with 26 (18·4%) of Phortica flies recorded as being positive by PCR. Sequences from positive PCR products were 99% identical to sequences of the corresponding species available in GenBank (AY207464). At site B, 106 (17·6%) of 602 dissected P. okadai were found to be infected by T. callipaeda larvae (different stages) and in total 62 L3 were recovered from the proboscis of 34 (5·6%) flies. The shortest time in which L3 were found was at day +14, +17, +19, and +50 p.i. respectively, depending on the environmental temperatures. Of 30 flies overwintered for 6 months, 6 L3 were detected at day +180 p.i. in 3 flies (10%). The biology of larval development was reconstructed on the basis of the dissection of 602 P. okadai-infected flies and the morphology of larval stages in the insect body described. The present work provides evidence that P. variegata and P. okadai act as vectors for T. callipaeda in southern Europe and in China, respectively. The phenomenon of overwintering is described here for the first time for T. callipaeda and discussed. Finally, the relationship between T. callipaeda and its fly vector is considered in light of disease prophylaxis and to model its dissemination into habitats and environments favourable to Phortica flies.

Hydrogenated amorphous silicon nanoparticles with an average diameter of 150 nm have been synthesized by high-density plasma chemical vapor deposition. The particles are deposited onto a conducting substrate and are then surrounded by an insulating matrix, electrically isolating the particles. Electrical contact is made to the top of each nanoparticle; the current-voltage characteristics of the nanoparticles indicate that transport is space-charge limited through the a-Si:H. The spectral density of the current fluctuations in the a-Si:H nanoparticles is well described by a 1/f frequency dependence for frequency f. However, the octave separation dependence of the correlation coefficients of the noise power for the nanoparticles are very well described by an ensemble of fluctuators whose amplitudes are independently modulated in parallel, rather than the serial kinetics typically observed in bulk a-Si:H.