The merged droplets have great practical application value in protein synthesis and crystallization. In this paper, the effect of geometry configuration on the merged droplet formation in a double T-junction microchannel is studied by three-dimensional numerical simulation using the level-set method. There are three important parameters in the geometry configuration of the microchannel, namely angle between two phases (alpha), height-to-width ratio (Lambda= H/w(c)), and intersection width ratio (Gamma=w(d)/w(c)). In this study we found that a critical value of the two-phase angle is 60 degrees. When the angle is 60 degrees, the effective diameter of the merged droplet is the smallest and the generation frequency is the fastest under the same physical condition. We found that height-to-width ratio and intersection width ratio have a critical value of 1.0. When height-to-width ratio or intersection width ratio is 1.0, the shearing capacity of the continuous relative dispersed phase reaches a maximum, thus the droplet diameter is minimized and the frequency is the fastest. Therefore, reasonable adjustment of these three factors is an effective method to solve the problem of the high-throughput monodispersemerged droplet formation. This work lays a solid theoretical foundation for the merged droplets in practical applications.
Viruses could rapidly diversify into variants, which has long been known to facilitate viral adaption in the host. Recent studies showed that cooperation among variants and wild-type (WT) also increased viral fitness. Here, a mutant of sC69∗ in small hepatitis B surface protein (SHBs) that resulted in premature stop was investigated and the frequency of sC69∗ was 4.37% (19/435), most of which coexisted with the WT (78.95%, 15/19), indicating mixed viral populations. Functional studies showed that sC69∗ mutant was associated with lower viral spread, but could be rescued by coexisting with the WT. The sC69∗ mutant showed to attenuate host innate immune response during infection and poly (I:C) treatment such as IL29, ISG15, and RIG-I (p < 0.05). The lower immune response was not caused by the lower replication of sC69∗ mutant. Our data provide information that sC69∗ coexisting with the WT might facilitate the fitness and persistence of the viral quasispecies in the host.
Keywords: HBV; innate immune response; sC69∗; truncated mutant; viral infectivity.
Reflective metasurfaces are utilized as a bridge linking propagating waves and surface waves. However, the effective constitutive parameters (permittivity and permeability) cannot be retrieved by conventional theory without transmission coefficients. In this paper, an innovative method based on a quasi-one-port network model is proposed to robustly retrieve the effective electromagnetic parameters (εeff, μeff, neff, and zeff) for reflective metasurfaces with isotropic unit cells. The validity of the method is demonstrated by imping TE-polarized terahertz waves normally and obliquely (10°) on the multiple-layer unit cells. The effective boundary of the multiple-layer cells is determined by minimizing the deviation of the effective refractive indices from 0.1018 to 0.0260 using a genetic algorithm, which increases the consistency of the retrieval results. The sensitivity of the effective constitutive parameters to the accuracy of reflection coefficients and nonzero incident angle θi is also discussed. This method is beneficial for the design of reflective metasurfaces or multichannel reflectors, the coupling of spoof space plasmon polaritons, and other applications of anomalous reflection.
Water-saving irrigation (WSI) is a promising management practice for sustainable rice production. Shallow-wet irrigation (SWI), controlled irrigation (CI), intermittent irrigation (II), and rain-gathering irrigation (RGI) are four common WSI regimes used in China. Their water saving, pollutant reducing, and yield increasing effects were analysed based on literature survey from multi-site field studies across China. An index system considering the applicability and effect of different WSI regimes was developed to identify their potential distributions across China. The potential overall effect of WSI practices at the country level was then estimated. Results showed that CI had the highest average water saving rate (WSR) of 35.12% and the highest average pollutant reducing rate (PRR) of 54.97%, followed by RGI, SWI, and II; while CI had the lowest average yield increasing rate (YIR) (0.79%), followed by II (5.40%), SWI (8.12%), and RGI (11.80%). Overall, the larger the WSR, the larger higher PRR; but the yield increasing effect will be diminished when the WSR is increased to a certain extent due to the resulting rice water stress. About 94.19% of the total paddy area in China are suitable for WSI practices and the unsuitable ones are mainly due to soil structure deterioration and low soil fertility. SWI is the most applicable WSI regime, suitable for 90.03% of paddy fields, followed by CI and II (23.33%), and RGI (4.16%). By full implementation of appropriate WSI regimes at the country level, the total WSR, PRR, and YIR are likely to reach 22.06–26.41%, 32.11–39.11%, and 5.39–6.87%, respectively. The application of WSI practices in China has noticeable potential to alleviate water shortage and non-point source pollution while ensuring high yield.
Previous studies on large-scale patterns in plant richness and underlying mechanisms have mostly focused on forests and mountains, while drylands covering most of the world's grasslands and deserts are more poorly investigated for lack of data. Here, we aim to 1) evaluate the plant richness patterns in Inner Asian drylands; 2) compare the relative importance of contemporary environment, historical climate, vegetation changes, and mid-domain effect (MDE); and 3) explore whether the dominant drivers of species richness differ across growth forms (woody vs herbaceous) and range sizes (common vs rare). Distribution data and growth forms of 13 248 seed plants were compiled from literature and species range sizes were estimated. Generalized linear models and hierarchical partitioning were used to evaluate the relative contribution of different factors. We found that habitat heterogeneity strongly affected both woody and herbaceous species. Precipitation, climate change since the mid-Holocene and climate seasonality dominated herbaceous richness patterns, while climate change since the Last Glacial Maximum dominated woody richness patterns. Rare species richness was strongly correlated with precipitation, habitat heterogeneity and historical climatic changes, while common species richness was strongly correlated with MDE (woody) or climate seasonality (herbaceous). Temperature had little effects on the species richness patterns of all groups. This study represents the first evaluation of the large-scale patterns of plant species richness in the Inner Asian drylands. Our results suggest that increasing water deficit due to anthropogenic activities combined with future global warming may increase the extinction risk of many grassland species. Rare species (both herbaceous and woody) may face severe challenges in the future due to increased habitat destruction caused by urbanization and resource exploitation. Overall, our findings indicate that the hypotheses on species richness patterns based on woody plants alone can be insufficient to explain the richness patterns of herbaceous species.
To enhance the long-term immobilization of radioactive wastes, ferrihydrite nanoparticles were incorporated into cementitious materials. The effects of ferrihydrite nanoparticles on the physicochemical and mechanical properties of cementitious materials and the immobilization of uranium (U), strontium (Sr) and cesium (Cs) were investigated. Adding ferrihydrite nanoparticles at 0.65%, 1.30%, 3.90% and 6.50% of cement weight slightly improved compressive strength by 5–11%, but dramatically reduced U leaching by 50–57%. The enhanced U immobilization was attributed to the strong adsorption of U by ferrihydrite nanoparticles, and the structural incorporation of U into hematite formed during ferrihydrite recrystallization. Although ferrihydrite nanoparticles had weaker effect than hematite nanoparticles on improving cement hydration and reducing permeability, they exhibit stronger U immobilization capacity. In contrast, incorporating ferrihydrite nanoparticles into cementitious materials had no significant effects on Cs and Sr leaching and no detectable adsorption of Sr and Cs. This study elucidated the fundamental differences in the interactions between ferrihydrite nanoparticles and U, Sr or Cs within cementitious systems that led to the distinctive immobilization mechanisms for these radionuclides. It generated new mechanistic understandings of U, Sr and Cs leaching from cementitious barriers modified by Fe-based nanoparticles, and proposed a new approach for enhancing long-term immobilization of U.
With the extensive application of graphene oxide (GO), its leakage and release into wastewater treatment plants become inevitable. However, the toxicity of graphene oxide (GO) on nitrification process and the underlying mechanisms still remain unclear. In this study, the toxic effects of GO at concentration of 10 and 100 mg/L in 4 h and 10 days were evaluated with sealed reactors operated in sequencing batch mode. In the initial 4 h, both GO concentrations showed no negative effect on nitrogen conversion. However, the exposure to 100 mg/L GO significantly weakened the NH+ 4-N and NO- 2-N conversion capabilities and intensified the nitrous oxide (N2O) generation after 10 days. Extracellular polymeric substance (EPS) analysis suggested that 100 mg/L GO decreased the protein content of the nitrifying activated sludge. Moreover, reactive oxygen species (ROS) level was promoted by 100 mg/L GO owing to the impaired endogenous antioxidant enzymes including superoxide dismutase (SOD) and catalase (CAT), which caused oxidative stress to bacteria. Finally, quantitative PCR results confirmed that nitrite-oxidizing bacteria (NOB) and complete ammonia oxidizing bacteria (CAOB) were more sensitive to GO, which was the primary cause for the significant promotion of N2O generation in the high GO concentration. This study offered new insights in the toxicity of GO on nitrification and N2O generation in the terms of dose and exposure time.