A new approach to target development for laboratory astrophysics experiments at high-power laser facilities is presented. With the dawn of high-power lasers, laboratory astrophysics has emerged as a field, bringing insight into physical processes in astrophysical objects, such as the formation of stars. An important factor for success in these experiments is targetry. To date, targets have mainly relied on expensive and challenging microfabrication methods. The design presented incorporates replaceable machined parts that assemble into a structure that defines the experimental geometry. This can make targets cheaper and faster to manufacture, while maintaining robustness and reproducibility. The platform is intended for experiments on plasma flows, but it is flexible and may be adapted to the constraints of other experimental setups. Examples of targets used in experimental campaigns are shown, including a design for insertion in a high magnetic field coil. Experimental results are included, demonstrating the performance of the targets.

A multistep pulse compressor (MPC) based on a single-pass single-grating pair (SSGP) is proposed to simplify the entire multi-petawatt (PW) compressor. Only one grating pair with relatively long perpendicular distance is used to generate the same amount of spectral chirp compared with a four-grating main compressor. As SSGP compressor induces the largest spatial chirp, it can introduce the best beam-smoothing effect to the laser beam on the last grating. When considering the diffraction loss of only two gratings, the total compression efficiency of the SSGP compressor is even larger than that of a four-grating main compressor. Furthermore, the wavefront aberration induced by the SSGP compressor can be better compensated by using deformable mirrors; however, it is difficult or complicated to be well compensated in a four-grating compressor. Approximately 50–100 PW laser pulses can be obtained using this SSGP-based multistage-smoothing MPC with a single laser beam.

Recently, the collisionless pitch-angle scattering for relativistic runaway electrons (REs) in toroidal geometries such as tokamaks was discovered through a full orbit simulation approach (Liu et al., Nucl. Fusion, vol. 56, 2016, p. 064002), and it was then theoretically investigated that a new expression for the magnetic moment, including the second-order corrections, could essentially reproduce the so-called collisionless pitch-angle scattering process (Liu et al., Nucl. Fusion, vol. 58, 2018, p. 106018). In this paper, with synchrotron radiation, extensive numerical verification of the validity of the high-order guiding-centre theory is given for simulations involving REs by incorporating such an expression for the magnetic moment into our particle tracing code. A high-order guiding-centre simulation approach with synchrotron radiation (HGSA) is applied. Synchrotron radiation plays an essential role in the life cycle of REs. The energy of REs first increases and then becomes saturated until the electric field acceleration is balanced by the radiation dissipation. Unfortunately, the process cannot be simulated accurately with the standard guiding-centre model, i.e. the first-order guiding-centre model. Remarkably, it is found that the HGSA can effectively produce the fundamental process of REs. Since the time scale of the energy saturation of REs is close to seconds, the computational cost becomes significant. In order to save costs, it is necessary to estimate the time of energy saturation. An analytical estimate is derived for the time it takes for synchrotron drag to balance an accelerating electric field and the provided formula has been numerically verified. Test calculations reveal that HGSA is favourable for exploiting the dynamics of REs in tokamak plasmas.

A system of mutually interacting superprocesses with migration is constructed as the limit of a sequence of branching particle systems arising from population models. The uniqueness in law of the superprocesses is established using the pathwise uniqueness of a system of stochastic partial differential equations, which is satisfied by the corresponding system of distribution function-valued processes.

Fine fibre immersed in different flows is ubiquitous. For a fibre in shear flows, most motion modes appear in the flow-gradient plane. Here the two-dimensional behaviours of an individual flexible flap in channel flows are studied. The nonlinear coupling of the fluid inertia ($\textit {Re}$), flexibility of the flap ($K$) and channel width ($W$) is discovered. Inside a wide channel (e.g. $W=4$), as $K$ decreases, the flap adopts rigid motion, springy motion, snake turn and complex mode in sequence. It is found that the fluid inertia tends to straighten the flap. Moreover, $\textit {Re}$ significantly affects the lateral equilibrium location $y_{eq}$, therefore affecting the local shear rate and the tumbling period $T$. For a rigid flap in a wide channel, when $\textit {Re}$ exceeds a threshold, the flap stays inclined instead of tumbling. As $\textit {Re}$ further increases, the flap adopts swinging mode. In addition, there is a scaling law between $T$ and $\textit {Re}$. For the effect of $K$, through the analysis of the torque generated by surrounding fluid, we found that a smaller $K$ slows down the tumbling of the flap even if $y_{eq}$ is comparable. As $W$ decreases, the wall confinement effect makes the flap easier to deform and closer to the centreline. The tumbling period would increase and the swinging mode would be more common. When $W$ further decreases, the flaps are constrained to stay inclined, parabolic-like or one-end bending configurations moving along with the flow. Our study may shed some light on the behaviours of a free fibre in flows.

Reconstructing the history of elite communication in ancient China benefits from additional archaeological evidence. We combine textual analysis with new human stable carbon and nitrogen isotope data from two Chu burials in the Jingzhou area to reveal significant dietary differences among Chu nobles of the middle Warring States period (c. 350 BC). This research provides important new information on the close interaction between the aristocratic families of the Qin and Chu.

This study aimed to evaluate to what extent the different interval times between trophectoderm (TE) biopsy and vitrification influence the clinical outcomes in preimplantation genetic testing (PGT) cycles. Patients who underwent frozen embryo transfer (FET) after PGT between 2015 and 2019 were recruited. In total, 297 cycles with single day 5 euploid blastocyst transfer were included. These cycles were divided into three groups according to the interval times: <1 h group, 1–2 h group, and ≥2 h group. Blastocyst survival, clinical pregnancy, miscarriage, and ongoing pregnancy rates were compared. The results showed that, in PGT-SR cycles, survival rate in the ≥2 h group (96.72%) was significantly lower than in the <1 h group (100%, P = 0.047). The clinical pregnancy rate in the ≥2 h group was 55.93%, significantly lower than in the <1 h group (74.26%, P = 0.017). The ongoing pregnancy rates in the 1–2 h group and the ≥2 h group were 48.28% and 47.46%, respectively, significantly lower than that in the <1 h group (67.33%, P < 0.05). The miscarriage rate in the 1–2 h group was 18.42%, significantly higher than that in the <1 h group (5.33%, P = 0.027). In PGT-A cycles, the clinical pregnancy and ongoing pregnancy rates in the <1 h group were 67.44% and 53.49%, respectively, higher than that in the 1–2 h group (52.94%, 47.06%, P > 0.05) and the ≥2 h group (52.63%, 36.84%, P > 0.05). In conclusion, vitrification of blastocysts beyond 1 h after biopsy significantly influences embryo survival and clinical outcomes and is therefore not recommended.

As essential specifications of correlation domain for signal quality evaluation, distortions of the S-curve, including bias and slope distortions of the zero-crossing point, are usually selected as indicators of optimisation in the process of designing the channels of receivers or navigation satellites. Focusing on this issue, we present a detailed analysis of slope distortion in the presence of group delay and amplitude distortions. After validating the theoretical results, we present further discussions about the impacts of different group delay terms on slope distortions. The results indicate that both the odd-order and the even-order terms have impacts on the slope distortion, and higher odd-order terms have less slope distortion compared with the lower odd-order terms. These results are useful for evaluating the slope distortion from the group delay and guiding improvement in design of the channel.

The epidemic of coronavirus disease 2019 (COVID-19) began in China and had spread rapidly to many other countries. This study aimed to identify risk factors associated with delayed negative conversion of SARS-CoV-2 in COVID-19 patients. In this retrospective single-centre study, we included 169 consecutive patients with confirmed COVID-19 in Zhongnan Hospital of Wuhan University from 15th January to 2nd March. The cases were divided into two groups according to the median time of SARS-CoV-2 negative conversion. The differences between groups were compared. In total, 169 patients had a median virus negative conversion time of 18 days (interquartile range: 11–25) from symptom onset. Compared with the patients with short-term negative conversion, those with long-term conversion had an older age, higher incidence of comorbidities, chief complaints of cough and chest distress/breath shortness and severer illness on admission, higher level of leucocytes, neutrophils, aspartate aminotransferase, creatine kinase and erythrocyte sedimentation rate (ESR), lower level of CD3+CD4+ lymphocytes and albumin and more likely to receive mechanical ventilation. In multivariate analysis, cough, leucocytes, neutrophils and ESR were positively correlated with delayed virus negative conversion, and CD3+CD4+ lymphocytes were negatively correlated. The integrated indicator of leucocytes, neutrophils and CD3+CD4+ lymphocytes showed a good performance in predicting the negative conversion within 2 weeks (area under ROC curve (AUC) = 0.815), 3 weeks (AUC = 0.804), 4 weeks (AUC = 0.812) and 5 weeks (AUC = 0.786). In conclusion, longer quarantine periods might be more justified for COVID-19 patients with cough, higher levels of leucocytes, neutrophils and ESR and lower levels of CD3+CD4+ lymphocytes.

A magnetic field configuration of an island divertor for a quasi-axisymmetric stellarator (CFQS) is proposed. The configuration incorporates large islands surrounding the core confinement region. The interface between the core region and the peripheral region of the island divertor is a clear magnetic separatrix similar to a tokamak divertor. The structure of divertor magnetic field lines is very regular without stochasticity and the connection length is sufficiently long for good divertor performance. Such a divertor configuration is produced in the magnetic field configuration for the CFQS device, which is now under construction in China.

A highly active catalyst of cerium–tungsten–titanium mixed oxide was synthesized by introducing Ce4+ and H2O2 in the base sample of Ce20W10Ti100Oz–Ce3+. As a consequence, the NH3-SCR activity of Ce20W10Ti100Oz–Ce3+ is significantly improved as the additives of Ce4+ and H2O2 enlarge the Brunauer–Emmett–Teller (BET) surface area by refining its pore size. Meanwhile, the introduction of Ce4+ increases the Lewis acid sites of Ce20W10Ti100Oz–Ce3+ and decreases its low-temperature Brønsted acid sites. The further addition of H2O2 improves the Brønsted acid sites and dispersion of cerium/tungsten species, and thereby enhances the concentrations of the adsorbed oxygen (Oα) and the adsorbed oxygen $\lpar {\rm {O}^{\prime}}_{\rm \alpha} \rpar$ due to the activation of chemisorbed water on the surface of the catalyst. The addition of Ce4+ and H2O2 shows a synergistic promotional effect, which is due to the largest BET surface area and the highest concentrations of Oα or/and ${\rm {O}^{\prime}}_{\rm \alpha}$. Ce20W10Ti100Oz–Ce3+:Ce4+ = 17.5:2.5 + H2O2 exhibits the highest catalytic activity compared with the conventional ones (Fig. 5).

Flavonoid-rich foods have shown a beneficial effect against non-alcoholic fatty liver disease (NAFLD) in short-term randomised trials. It is uncertain whether the usual dietary intake of flavonoids may benefit patients with NAFLD. The present study evaluated the association between the usual intake of flavonoids and the risk of progression in NAFLD. The prospective study included 2694 adults from the Guangzhou Nutrition and Health Study. Face-to-face interviews using a seventy-nine-item FFQ were administered to assess habitual dietary flavonoid intake, while abdominal ultrasonography was conducted to evaluate the presence and degree of NAFLD, with measurements conducted 3 years apart. After adjustment for potential confounders, higher flavonoid intakes were gradely associated with reduced risks of worsen NAFLD status. The relative risks of worsening (v. non-worsening) NAFLD in the highest (v. lowest) quintile were 0·71 (95 % CI 0·54, 0·93) for total flavonoids, 0·74 (95 % CI 0·57, 0·95) for flavanones, 0·74 (95 % CI 0·56, 0·96) for flavan-3-ols, 0·90 (95 % CI 0·68, 1·18) for flavonols, 0·73 (95 % CI 0·56, 0·93) for flavones, 0·79 (95 % CI 0·61, 1·02) for isoflavones and 0·74 (95 % CI 0·57, 0·96) for anthocyanins. An L-shaped relationship was observed between total flavonoid intake and the risk of NAFLD progression. Path analyses showed that the association between flavonoids and NAFLD progression was mediated by decreases in serum cholesterol and homeostasis model assessment of insulin resistance. This prospective study showed that higher flavonoid intake was associated with a lower risk of NAFLD progression in the elderly overweight/obese Chinese population.

Parakmeria omeiensis is a Critically Endangered tree species in the family Magnoliaceae, endemic to south-west China. The tree is functionally dioecious, but little is known about the species’ status in the wild. We investigated the range, population size, age structure, habitat characteristics and threats to P. omeiensis. We located a total of 74 individuals in two populations on the steep slopes of Mount Emei, Sichuan province, growing under the canopy of evergreen broadleaved forest in well-drained gravel soil. A male-biased sex ratio, lack of effective pollinating insects, and habitat destruction result in low seed set and poor seedling survival in the wild. We have adopted an integrated conservation approach, including strengthening in situ conservation, cultivation of saplings, ex situ conservation and reintroduction, to protect this species. The successful conservation of P. omeiensis has important implications for the conservation of the genus Parakmeria and the family Magnoliaceae.

This report is on the synthesis by electrospinning of multiferroic core-shell nanofibers of strontium hexaferrite and lead zirconate titanate or barium titanate and studies on magneto-electric (ME) coupling. Fibers with well-defined core–shell structures showed the order parameters in agreement with values for nanostructures. The strength of ME coupling measured by the magnetic field-induced polarization showed the fractional change in the remnant polarization as high as 21%. The ME voltage coefficient in H-assembled films showed the strong ME response for the zero magnetic bias field. Follow-up studies and potential avenues for enhancing the strength of ME coupling in the core–shell nanofibers are discussed.

The study investigated antioxidant effects of Se on resilience to diquat-induced oxidative stress in nursery pigs. Thirty-five weaned pigs were individually housed and randomly assigned to one of the five treatments. Pigs were (1) fed a basal diet and intraperitoneally injected with sterile saline (negative control), (2) fed the basal diet and injected with diquat solution (positive control, PC), or fed the basal diet supplemented with 0·3 mg Se/kg as (3) sodium selenite (SS), (4) soyabean protein-chelated Se (SC) or (5) selenised yeast (SY) and intraperitoneally injected with diquat. Pigs were fed the experimental diets for 17 d and injected with diquat at 10 mg/kg body weight or saline on the 11th day of the study (day 0 post-injection (PI)). Diquat exposure induced acute stress and innate immune activation (P < 0·05) at 6 h PI and compromised (P < 0·05) plasma glutathione peroxidase activity on day 2 PI, which was accompanied by an increase in plasma malondialdehyde at 6 h and day 2 PI (P < 0·10). Organic Se, particularly SY, enhanced (P < 0·05) endogenous antioxidant activity in various aspects compared with the PC group. The growth rate and feed intake from day 0 to day 7 PI were significantly lower in the PC, SS and SC groups than the NC group (P < 0·05). Untargeted metabolomics analysis revealed that twenty-two hepatic metabolites (false discovery rate < 0·15) associated with lipid and cellular antioxidant metabolism were altered by diquat. SY restored hepatic metabolic profiles in some but not all samples.

The present study was conducted to evaluate the effects of glucose, soya oil or glutamine on jejunal morphology, protein metabolism and protein expression of the mammalian target of rapamycin complex 1 (mTORC1) signalling pathway in jejunal villus or crypt compartment of piglets. Forty-two 21 d-weaned piglets were randomly allotted to one of the three isoenergetic diets formulated with glucose, soya oil or glutamine for 28 d. On day 14 or 28, the proteins in crypt enterocytes were analysed with isobaric tags for relative and absolute quantification and proteins involved in mTORC1 signalling pathway in villus or crypt compartment cells were determined by Western blotting. Our results showed no significant differences (P > 0·05) in jejunal morphology among the three treatments on day 14 or 28. The differentially expressed proteins mainly took part in a few network pathways, including antimicrobial or inflammatory response, cell death and survival, digestive system development and function and carbohydrate metabolism. On day 14 or 28, there were higher protein expression of eukaryotic initiation factor-4E binding protein-1 in jejunal crypt compartment of piglets supplemented with glucose or glutamine compared with soya oil. On day 28, higher protein expression of phosphor-mTOR in crypt compartment was observed in piglets supplemented with glucose compared with the soya oil. In conclusion, the isoenergetic glucose, soya oil or glutamine did not affect the jejunal morphology of piglets; however, they had different effects on the protein metabolism in crypt compartment. Compared with soya oil, glucose or glutamine may be better energy supplies for enterocytes in jejunal crypt compartment.

Cinnamomum chago is a woody species of the family Lauraceae endemic to Yunnan province, China, previously known from only one location, and categorized as a Plant Species with Extremely Small Population. We surveyed to determine the distribution and population size of C. chago, characterize its habitat, identify any threats, assess its conservation status, and provide guidelines for its management and conservation. During 2014–2017 we found only 64 mature C. chago, in five locations. These small, fragmented populations occur along Lancang River in Dali Prefecture at altitudes of 2,200–2,400 m. The species' extent of occurrence is c. 923 km2, with an area of occupancy of c. 60 km2. The habitat of the species has been degraded by expansion of pastoral activities and deforestation. We recommend categorization of C. chago as Endangered on the IUCN Red List, prevention of the collection of seeds and wood of the species, protection and monitoring, and ex situ propagation for future reintroductions.

Let φ : ℝn × [0, ∞) → [0, ∞) satisfy that φ(x, · ), for any given x ∈ ℝn, is an Orlicz function and φ( · , t) is a Muckenhoupt A∞ weight uniformly in t ∈ (0, ∞). The (weak) Musielak–Orlicz Hardy space Hφ(ℝn) (WHφ(ℝn)) generalizes both the weighted (weak) Hardy space and the (weak) Orlicz Hardy space and hence has wide generality. In this paper, two boundedness criteria for both linear operators and positive sublinear operators from Hφ(ℝn) to Hφ(ℝn) or from Hφ(ℝn) to WHφ(ℝn) are obtained. As applications, we establish the boundedness of Bochner–Riesz means from Hφ(ℝn) to Hφ(ℝn), or from Hφ(ℝn) to WHφ(ℝn) in the critical case. These results are new even when φ(x, t): = Φ(t) for all (x, t) ∈ ℝn × [0, ∞), where Φ is an Orlicz function.