This study assessed the impact and cost-effectiveness of pre-exposure prophylaxis (PrEP) in reducing HIV infections and HIV-related deaths among four key populations in China: men who have sex with men (MSM). Female sex workers (FSW), people who inject drugs (PWID), and HIV-negative partners of serodiscordant couples (SDC). Decision-analytic Markov models simulated HIV transmission and progression in cohorts of 100,000 adults over 40 years under three strategies: no PrEP, daily oral PrEP, and on-demand oral PrEP evaluated nationaly and high-incidence provinces. Cost-effectiveness was measured using a willingness-to-pay threshold of US$37,653 per QALY. Across all populations, on-demand PrEP was the most cost-effective strategy. Among MSM, it was cost-effective both nationwide (ICER: $4,554/QALY) and in high-incidence provinces (ICER: $1,045-2,129/QALY), reducing new infections by 24.7%. Daily PrEP was also const-effective for MSM nationally and prevented 19.9% of infections. For FSW, on-demand PrEP was cost-effective in high-incidence provinces (ICER: $25,399-37,045/QALY), reducing infections by 21.8%-22.5%. For PWID, it was cost-effective in high-incidence provinces (ICER: $10,361-29,560/QALY), reducing infections by 15.5%-17.9%. For HIV-negative partners of SDC, on-demand PrEP was cost-effective both nationally and in high-incidence provinces, reducing infections by 24.0%. Overall, on-demand PrEP offers substantial health and economic benefits, particularly for HIV-negative partners of SDC and high-incidence regions.

The existing studies on vortex rings have concentrated on non-zero circulation. However, the cases of zero circulation may also be significantly noteworthy on both theoretical and practical grounds. As the first attempt on this subject, in this paper a family of viscous laminar vortex rings with zero circulation and a moderate ratio of core radius to ring radius is studied using numerical simulations of the incompressible Navier–Stokes equations. This unusual zero circulation is achieved by assigning a special layered vorticity distribution with alternate signs to the vortex core. At the initial moment, the ring is axisymmetric, swirl-free and of a circular cross-section. It is found that the axial symmetry and the non-swirl nature of the vortex ring are preserved during the evolution, and the vortex ring endures a transition from the initial layered structure to a shell structure, then degenerates to an ordinary vortex ring with non-zero circulation at last. Significant vorticity cancellation is observed due to the interactions among the layered structures. A new Reynolds number, based on the absolute value of vorticity, is applied to the zero-circulation vortex rings in the present work. For such vortex rings, cases of both zero and non-zero vortical impulse can happen, unlike the ordinary ones with only non-zero vortical impulse. Additionally, it is found that the vortical impulse can be irrelevant to the ring diameter. The study may shed light on modelling certain real flows characterised by distinct vortex structures or configurations.

Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) is a destructive monophagous pest of mulberry, Morus Linnaeus (Moraceae), trees. In order to identify mulberry cultivars resistant to G. pyloalis, 12 cultivars were examined using field and in vitro testing. Field observations indicated that cultivars AlbapC, BombyL, LaeviT, and CathaB had less than 10.0% damage, with no observed damage on the CathaB cultivar. The life table parameters showed that CathaB cultivar had the longest larval and pupal duration (23.2 days in total), the shortest adult period (5.3 days), the lowest rates of both pupation (55.0%) and adult emergence (69.7%), the highest adult mortality (61.7%), the lowest average weight of pupae (30.4 mg), and the lowest daily oviposition (5.0 eggs/female/day). The larval performance of G. pyloalis in the field revealed that CathaB had the lowest larval density. Correlation analyses confirmed that significant correlations exist between all the performance parameters of G. pyloalis for both the observed damage and larval performance. Leaf characterisation of selected cultivars indicated CathaB had significantly higher values of leaf wax, trichome density, soluble glucose, and protein contents compared to MultiQ. This study would be a valuable reference for evaluating pest-resistant cultivars and establishing a theoretical foundation for managing G. pyloalis.

The interaction of a swimmer with unsteady vortices in complex flows remains a topic of interest and open discussion. The present study, employing the immersed boundary method with a flexible fin model, explores swimming behaviours behind a circular cylinder with vortex-induced vibration (VIV). Five distinct swimming modes are identified on the $U_r$–$G_0$ plane, where $U_r$ denotes the reduced velocity, and $G_0$ represents the fin’s initial position. These modes include drifting upstream I/II (DU-I/II), Karman gait I/II (KG-I/II), and large oscillation (LO), with the DU-II, KG-II and LO modes being newly reported. The fin can either move around or cross through the vortex cores in the KG-I and KG-II modes, respectively, for energy saving and maintaining a stable position. When the upstream cylinder vibrates with its maximum amplitude, a double-row vortex shedding forms in the wake, allowing the DU-II mode to occur with the fin to achieve high-speed locomotion. This is attributed to a significant reduction in the streamwise velocity caused by vortex-induced velocity. Furthermore, a symmetry breaking is observed in the fin’s wake in the DU-II mode, potentially also contributing to high-speed locomotion. Overall, compared to the case without an upstream cylinder, we demonstrate that a self-propelled fin gains hydrodynamic advantages with various swimming modes in different VIV wakes. Interestingly, increased power transferred from flows by the oscillating cylinder leads to a more favourable environment for the downstream fin’s propulsion, indicating that a fin in VIV wakes obtains more advantages compared to the vortex street generated by a stationary cylinder.

Broadband frequency-tripling pulses with high energy are attractive for scientific research, such as inertial confinement fusion, but are difficult to scale up. Third-harmonic generation via nonlinear frequency conversion, however, remains a trade-off between bandwidth and conversion efficiency. Based on gradient deuterium deuterated potassium dihydrogen phosphate (KDxH2-xPO4, DKDP) crystal, here we report the generation of frequency-tripling pulses by rapid adiabatic passage with a low-coherence laser driver facility. The efficiency dependence on the phase-matching angle in a Type-II configuration is studied. We attained an output at 352 nm with a bandwidth of 4.4 THz and an efficiency of 36%. These results, to the best of our knowledge, represent the first experimental demonstration of gradient deuterium DKDP crystal in obtaining frequency-tripling pulses. Our research paves a new way for developing high-efficiency, large-bandwidth frequency-tripling technology.

Compacted bentonite, used as an engineering barrier for permanent containment of high-level radioactive waste, is susceptible to mineral evolution resulting in compromise of the expected barrier performance due to alkaline–thermal chemical interaction in the near-field. To elucidate the mineral-evolution mechanisms within bentonite and the transformation of the nuclide adsorption properties during that period, experimental evolution of bentonite was conducted in a NaOH solution with a pH of 14 at temperatures ranging from 60 to 120°C. The results showed that temperature significantly affects the stability of minerals in bentonite under alkali conditions. The dissolution rate of fine-grained cristobalite in bentonite exceeds that of smectite, with the phase-transition products of smectite being temperature-dependent. As the temperature rises, smectite experiences a three-stage transformation: initially, at 60°C, the lattice structure thins due to the collapse of the octahedral sheets; at 80°C, the lattice disintegrates and reorganizes into a loose framework akin to albite; and by 100°C, it further reorganizes into a denser framework resembling analcime. The adsorption properties of bentonite exhibit a peak inflection point at 80°C, where the dissolution of the smectite lattice eliminates interlayer pores and exposes numerous polar or negatively charged sites which results in a decrease in specific surface area and an increase in cation exchange capacity and adsorption capacity of Eu3+. This research provides insights into the intricate evolution of bentonite minerals and the associated changes in radionuclide adsorption capacity, contributing to a better understanding of the stability of bentonite barriers and the effective long-term containment of nuclear waste.

Several novel anthropometric indices, including paediatric body adiposity index (BAIp) and triponderal mass index (TMI), have emerged as potential tools for estimating body fat in preschool children. However, their comparative validity and accuracy, particularly when compared with established indicators such as BMI, have not been thoroughly investigated. This cross-sectional study enrolled 2869 preschoolers aged 3–6 years in Wuhan, China. The non-parametric Bland–Altman analysis was employed to evaluate the agreement between BMI, BAIp and TMI with percentage of body fat (PBF), determined by bioelectrical impedance analysis (BIA), serving as the reference measure of adiposity. Additionally, receiver operating characteristic curve analysis was conducted to assess the effectiveness of BMI, BAIp and TMI in screening for obesity. BAIp demonstrated the least bias in estimating PBF, showing discrepancies of 3·64 % (95 % CI 3·40 %, 4·12 %) in boys and 3·95 % (95 % CI 3·79 %, 4·23 %) in girls. Conversely, BMI underestimated PBF by 3·89 % (95 % CI 3·70 %, 4·37 %) in boys and 4·81 % (95 % CI 4·59 %, 5·09 %) in girls, while TMI also underestimated PBF by 5·15 % (95 % CI 4·90 %, 5·52 %) in boys and 5·68 % (95 % CI 5·30 %, 5·91 %) in girls. BAIp exhibited the highest AUC values (AUC = 0·867–0·996) in boys, whereas in girls, there was no statistically significant difference between BMI (AUC = 0·936, 95 % CI 0·921, 0·948) and BAIp (AUC = 0·901, 95 % CI 0·883, 0·916) in girls (P = 0·054). In summary, when considering the identification of obesity, BAIp shows promise as a screening tool for both boys and girls.

This paper retrospectively analysed the prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) in some parts of China. Between January 2013 and December 2019, we collected 4,145 respiratory samples, including pharyngeal swabs and alveolar lavage fluid. The highest PCR-positive rate of M. pneumoniae was 74.5% in Beijing, the highest resistance rate was 100% in Shanghai, and Gansu was the lowest with 20%. The highest PCR-positive rate of M. pneumoniae was 74.5% in 2013, and the highest MRMP was 97.4% in 2019; the PCR-positive rate of M. pneumoniae for adults in Beijing was 17.9% and the MRMP was 10.48%. Among the children diagnosed with community-acquired pneumonia (CAP), the PCR-positive and macrolide-resistant rates of M. pneumoniae were both higher in the severe ones. A2063G in domain V of 23S rRNA was the major macrolide-resistant mutation, accounting for more than 90%. The MIC values of all MRMP to erythromycin and azithromycin were ≥ 64 μg/ml, and the MICs of tetracycline and levofloxacin were ≤ 0.5 μg/ml and ≤ 1 μg/ml, respectively. The macrolide resistance varied in different regions and years. Among inpatients, the macrolide-resistant rate was higher in severe pneumonia. A2063G was the common mutation, and we found no resistance to tetracycline and levofloxacin.

Mythimna separata (Lepidoptera: Noctuidae) is an omnivorous pest that poses a great threat to food security. Insect antimicrobial peptides (AMPs) are small peptides that are important effector molecules of innate immunity. Here, we investigated the role of the AMP cecropin B in the growth, development, and immunity of M. separata. The gene encoding M. separata cecropin B (MscecropinB) was cloned. The expression of MscecropinB was determined in different developmental stages and tissues of M. separata. It was highest in the prepupal stage, followed by the pupal stage. Among larval stages, the highest expression was observed in the fourth instar. Tissue expression analysis of fourth instar larvae showed that MscecropinB was highly expressed in the fat body and haemolymph. An increase in population density led to upregulation of MscecropinB expression. MscecropinB expression was also upregulated by the infection of third and fourth instar M. separata with Beauveria bassiana or Bacillus thuringiensis (Bt). RNA interference (RNAi) targeting MscecropinB inhibited the emergence rate and fecundity of M. separata, and resulted in an increased sensitivity to B. bassiana and Bt. The mortality of M. separata larvae was significantly higher in pathogen plus RNAi-treated M. separata than in controls treated with pathogens only. Our findings indicate that MscecropinB functions in the eclosion and fecundity of M. separata and plays an important role in resistance to infection by B. bassiana and Bt.

We report an experimental study of the formation and evolution of laminar thermal structures generated by a small heat source, with a focus on their correlation to the thermal boundary layer and effects of heating time $t_{heat}$. The experiments are performed over the flux Rayleigh number ($Ra_f$) range $2.1\times 10^6 \leq Ra_f \leq 3.6\times 10^{7}$ and the Prandtl number ($Pr$) range $28.6 \leq Pr \leq 904.7$. The corresponding Rayleigh number ($Ra= t_{heat}\,Ra_{f}/\tau _0\,Pr$) range is $900 \leq Ra \leq 4\times 10^{4}$, where $\tau _0$ is a diffusion time scale. For thermal structures generated by continuous heating (i.e. starting plumes), their formation process exists three characteristic times that are well reflected by changes in the thermal boundary layer thickness. These characteristic times, denoted as $t_{emit}$, $t_{recover}$ and $t_{static}$, correspond to the moments when the plume emission begins and completes, and when the thermal boundary layer becomes quasi-static, respectively. Their $Ra_f$–$Pr$ dependencies are found to be $t_{emit}/\tau _0\sim Ra_f^{-0.41}\,Pr^{0.41}$, $t_{recover}/\tau _0\sim Ra_f^{-0.48}\,Pr^{0.48}$ and $t_{static}/\tau _0\sim Ra_f^{-0.49}\,Pr^{0.33}$, respectively. Thermal structures generated by finite $t_{heat}$ exhibit similar evolution dynamics once $t_{heat} \ge t_{emit}$, with the accelerating stage behaving like starting plumes and the decay stage like thermals (i.e. a finite amount of buoyant fluids). It is further found that their maximum rising velocity experiences a transition in the $Ra$-dependence from $Ra$ to $(Ra\ln Ra)^{0.5}$ at $Ra \simeq 6000$; and their maximum acceleration reaches the value of starting plumes at $t_{heat}\simeq t_{recover}$, and remains unchanged for larger $t_{heat}$. In particular, the maximum rising velocity for the cases with $t_{heat} = t_{recover}$ follows a scaling relation $Ra_f^{0.37}\,Pr^{-0.37}$, in contrast to the relation $Ra_f^{0.48}\,Pr^{-0.48}$ for starting plumes. This study provides a more comprehensive understanding of laminar thermal structures, which are relevant to a range of processes in nature and laboratory systems such as Rayleigh–Bénard convection.

Hydrophobicity, swellability, and dispersion are important properties for organo-montmorillonites (OMnt) and have yet to be fully characterized for all OMnt configurations. The purpose of the present work was to examine the preparation of OMnt from the reaction of Ca2+-montmorillonite (Ca2+-Mnt) with a high concentration of surfactant and to reveal the relevant properties of hydrophobicity and dispersion of the resultant OMnt. A series of OMnt samples were prepared using a small amount of water and cetyltrimethylammonium bromide (CTAB) with a concentration more than the CTAB critical micelle concentration (CMC). The relationship between OMnt microstructure and the hydrophobicity and swellability properties was investigated in detail. The resulting OMnt samples were characterized using powder X-ray diffraction patterns (XRD), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric and differential thermogravimetry (TG-DTG), water contact angle tests, swelling indices, and transmission electron microscopy (TEM). The addition of CTAB and water in the OMnt preparation affected the OMnt microstructure and properties. An increase in CTAB concentration led to a more ordered arrangement of cetyltrimethylammonium (CTA+) cations in the interlayer space of the OMnt and a large amount of CTA+ cations on the outer surfaces of the OMnt. The swelling indices and the water contact angles of OMnt samples depended on the distribution of the CTAB surfactant on OMnt and the orientation of the surfactant hydrophilic groups on the inner and on the outer surfaces of OMnt. A maximum swelling index of 39 mL/g in xylene was achieved with an average water contact angle of 62.0° ± 2.0° when the amount of CTAB added was 2 times the cation exchange capacity (CEC) of Mnt and the lowest water to dry Mnt mass ratio was 3 during the preparation of OMnt samples. The platelets of OMnt aggregated together in xylene by electrostatic attraction and by hydrophobic interactions.

In order to establish a compact all-optical Thomson scattering source, experimental studies were conducted on the 45 TW Ti: sapphire laser facility. By including a steel wafer, mixed gas, and plasma mirror into a double-exit jet, several mechanisms, such as shock-assisted ionization injection, ionization injection, and driving laser reflection, were integrated into one source. So, the source of complexity was remarkably reduced. Electron bunches with central energy fluctuating from 90 to 160 MeV can be produced. Plasma mirrors were used to reflect the driving laser. The scattering of the reflected laser on the electron bunches led to the generation of X-ray photons. Through comparing the X-ray spots under different experimental conditions, it is confirmed that the X-ray photons are generated by Thomson scattering. For further application, the energy spectra and source size of the Thomson scattering source were measured. The unfolded spectrum contains a large amount of low-energy photons besides a peak near 67 keV. Through importing the electron energy spectrum into the Monte Carlo simulation code, the different contributions of the photons with small and large emitting angles can be used to explain the origin of the unfolded spectrum. The maximum photon energy extended to about 500 keV. The total photon production was 107/pulse. The FWHM source size was about 12 μm.

Montmorillonite (Mnt)-based solid acids have a wide range of applications in catalysis and adsorption of pollutants. For such solid acids, the acidic characteristic often plays a significant role in these applications. The objective of the current study was to examine the effects of H3PO4-activation and supporting WO3 on the textural structure and surface acidic properties of Mnt. The Mnt-based solid acid materials were prepared by H3PO4 treatment and an impregnation method with a solution of ammonium metatungstate (AMT) and were examined as catalysts in the dehydration of glycerol to acrolein. The catalysts were characterized by nitrogen adsorption-desorption, powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance ultraviolet-visible (DR UV-Vis) spectroscopy, temperature programmed desorption of NH3 (NH3-TPD), diffuse reflectance Fourier-transform infrared (DR FTIR) spectroscopy of adsorbed pyridine, and thermogravimetric (TG) analyses. The phosphoric acid treatment of Mnt created Brönsted and Lewis acid sites and led to increases in specific surface areas, porosity, and acidity. WO3 species influenced total acidity, acid strength, the numbers of Brönsted and Lewis acid sites, and catalytic performances. A high turnover frequency (TOF) value (31.2 h−1) based on a maximal 60.7% yield of acrolein was reached. The correlation of acrolein yield with acidic properties indicated that the cooperative role of Brönsted and Lewis acid sites was beneficial to the formation of acrolein and a little coke deposition (<3.3 wt.%). This work provides a new idea for the design of solid acid catalysts with cooperative Brönsted and Lewis acidity for the dehydration of glycerol.