A gradient metasurface wall structure operating in Ka-band is proposed. To reduce mutual coupling, side metallic walls with a designed metasurface arrays are incorporated into both sides of the unit antenna in the antenna array. These walls can also improve the performance of antenna based on the anomalous reflection. Simulation and experimental results show that the coupling coefficient reduces from -30 dB to -40 dB at the operating frequency. The 3dB beam width of the antenna is broadened from 35° to 38° in H plane and from 23.4° to 31.5° in E plane, due to the characteristic of controllable reflection direction. Because of the freedom in controlling the reflected waves and the high isolation, this gradient metasurface wall structure is of important application values in Millimeter-wave imaging system and MIMO system.
PDINH/MIL-88A(Fe) composites (PxMy) were fabricated from MIL-88A(Fe) and perylene-34,910-tetracarboxylic diimide (PDINH) via facile ball-milling strategy. The optimum P25M175 exhibited outstanding degradation performance toward chloroquine phosphate (CQ) by activating peroxydisulfate (PDS) under low power LED visible light. The synergistic effects of photocatalytic activations of PDS via the direct electron transfer PDS activation over P25M175 and indirect electron transfer PDS activation over pristine MIL-88A contributed to the boosted CQ degradation efficiency. The active species capture experimental data and electron spin resonance (ESR) determinations revealed that both active radicals (like SO4−, OH, O2−, h+) and nonradical singlet oxygen (1O2) participated in the CQ decomposition. The CQ degradation pathways and the toxicity evaluation of the intermediates were proposed based on LC–MS determination and DFT calculation. Also, P25M175 demonstrated good reusability and stability. The findings within this work offered deep insights into the mechanisms of organic pollutants degradation via photocatalysis-activated SR-AOP over Fe-MOF photocatalyst.
Although contemporary climate has been identified as one of the major determinants of large-scale species diversity patterns, its effect on species diversity greatly varies among clades. Understanding the drivers of the variation in species diversity–climate relationships (DCRs) across clades, which is critical for developing general mechanisms underlying the effects of climate on species diversity patterns, remains a current challenge. Using newly compiled distribution data of 914 Rosaceae species in China and a dated genus-level phylogeny, we first assessed the DCRs for the entire family, the two major growth forms (woody versus herbaceous), and each genus separately, and then explored the drivers underlying the variation in DCRs across different clades. We found that the DCRs significantly differed between woody and herbaceous plants and among different genera in this family. Closely related genera had more similar species diversity patterns and DCRs than expected. Both the ancestral climate niches of different genera and the discrepancy between contemporary and ancestral climate niches explained the variations in DCR slopes across genera with high explanatory power, indicating the effect of niche conservatism on DCRs. Our study suggests that niche conservatism is a major driver of DCR variations between clades, which enhances our understanding of the mechanisms underlying large-scale species diversity patterns.
Squalene can react with indoor ozone to generate a series of volatile and semi-volatile organic compounds, some of which may be skin or respiratory irritants, causing adverse health effects. Better understanding of the ozone/squalene reaction and product transport characteristics is thus important. In this study, we developed a physical–chemical coupling model to describe the behavior of ozone/squalene reaction products, that is, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA) in the gas phase and skin, by considering the chemical reaction and physical transport processes (external convection, internal diffusion, and surface uptake). Experiments without intervention were performed in a single-family house in California utilizing time- and space-resolved measurements. The key parameters in the model were extracted from 5 day data and then used to predict the behaviors in some other days. Predictions from the present model can reproduce the concentration profiles of the three compounds (ozone, 6-MHO, and 4-OPA) well (R2 = 0.82–0.89), indicating high accuracy of the model. Exposure analysis shows that the total amount of 6-MHO and 4-OPA entering the blood capillaries in 4 days can reach 14.6 and 30.1 $μ$g, respectively. The contribution of different sinks to ozone removal in the tested realistic indoor environment was also analyzed.
The tea family (Theaceae) has a highly unusual amphi-Pacific disjunct distribution: most extant species in the family are restricted to subtropical evergreen broadleaf forests in East Asia, while a handful of species occur exclusively in the subtropical and tropical Americas. Here, we used an approach that integrates the rich fossil evidence of this group with phylogenies in biogeographic analysis to study the processes behind this distribution pattern. We first combined genome-skimming sequencing with existing molecular data to build a robust species-level phylogeny for c.130 Theaceae species, resolving most important unclarified relationships. We then developed an empirical Bayesian method to incorporate distribution evidence from fossil specimens into historical biogeographic analyses and used this method to account for the spatiotemporal history of Theaceae fossils. We compared our method with an alternative Bayesian approach and show that it provides consistent results while significantly reduces computational demands which allows analyses of much larger data sets. Our analyses revealed a circumboreal distribution of the family from the early Cenozoic to the Miocene and inferred repeated expansions and retractions of the modeled distribution in the Northern Hemisphere, suggesting that the current Theaceae distribution could be the remnant of a larger continuous distribution associated with the boreotropical forest that has been hypothesized to occupy most of the northern latitudes in the early Cenozoic. These results contradict with studies that only considered current species distributions and showcase the necessity of integrating fossil and molecular data in phylogeny-based parametric biogeographic models to improve the reliability of inferred biogeographical events. [Biogeography; genome skimming; phylogenomics; plastid genome; Theaceae.]
Constructed wetlands (CWs) have been proved to be an alternative to the treatment of various wastewater. However, there are few studies focused on the removal performance and mechanisms of pollutants in pilot-scale CWs packed with novel solid carbon. In this study, we investigated the effect of poly-3-hydroxybutyrate-co-3hydroxyvalerate/polyacetic acid (PHBV/PLA) blends as carbon source on pollutant's transformation, microbial communities and functional genes in pilot-scale aeration-anoxic two-stage CWs for polishing rural runoff in southern China. Results showed a striking improvement of TN removal in CWs with PHBV/PLA blends (64.5%) compared to that in CWs with ceramsite (52.9%). NH4+-N (61.3-64.6%), COD (40.4-53.8%) and TP (43.6-47.1%) were also removed effectively in both two CWs. In addition, the strains of Rhodocyclaceae and Bacteroidetes were the primary denitrifiers on the surface of PHBV/PLA blends. Further, the aerobic stage induced gathering of 16 S and amoA genes and the anoxic zone with PHBV/PLA blends increased the nirS genes, which fundamentally explained the better denitrification performance in CW based on PHBV/PLA blends. Consequently, this study will provide straightforward guidance for the operation of engineering CWs packed with polymers to govern the low-C/N rural wastewater.
Plant species richness (PSR) is known to affect soil organic carbon (SOC) storage. However, due to the complex origin and composition of SOC, mechanisms driving the PSR-SOC relationship are not yet fully revealed, hampering an accurate prediction of SOC dynamics under changing plant diversity. Here we investigate the effect of PSR on SOC accumulation along a natural PSR and stand age gradient in a subtropical forest with plot, litter and soil properties being considered. Biomarkers and soil fractionation are used to delineate plant and microbial components of SOC and their influences on the PSR-SOC relationship in the topsoil (0–10 cm) versus subsoil (30–40 cm). We show that PSR does positively affect SOC concentrations at both depths even after considering the effects of substrate, edaphic properties and stand age. However, the PSR-SOC relationship is driven by different pathways in the topsoil versus subsoil. In the topsoil, PSR exerts a strong additive effect on SOC accumulation after the positive influence of substrate, edaphic properties and stand age, mainly regulated by plant-derived components (represented by lignin phenols, light fraction and particulate organic matter), followed by microbial residues. By contrast, PSR has a positive effect on the accrual of microbial-derived components (represented by amino sugars and mineral-associated organic matter) but not plant residues likely via affecting dissolved organic matter (DOM) and nitrogen availability in the subsoil (i.e., DOM-microbial pathway). As a result, microbial-derived components dominate SOC variations in the subsoil, while plant-derived components play a more important role in the topsoil. These findings provide novel information on the mechanistic links between PSR and SOC accumulation at different depths and highlight the role of PSR on long-term carbon sink potentials of soils, which may aid in predicting soil carbon dynamics with plant diversity changes in Earth's system model.
Reverse osmosis (RO) membranes are prone to fouling, which increases the cost of operation and decreases water recovery. In this study, a commercial membrane (ESPA2) was coated with an antiscaling material, i.e. polyacrylic acid (PAA), and an antimicrobial material, i.e. graphene oxide (GO), to reduce biofouling and scaling. Bare and modified membranes with polydopamine (ESPA2-PD), as a control, GO (ESPA2-GO), GO and PAA (ESPA2-GO-PAA), and PAA (ESPA2-PAA) were tested for their antiscaling and antibiofouling properties. ESPA2-GO and ESPA2-GO-PAA had the best performance. The latter showed 15% and 10% increase in normalized water flux compared to ESPA2 in mineral scaling and biofouling tests, respectively. This improvement can be attributed to the decrease in surface charge and the increase in hydrophilicity of membrane surface by both GO and PAA coating. Moreover, the antimicrobial characteristic of GO played a crucial role in reducing biofouling and PAA slightly enhanced antiscaling property when coated on ESPA2 but it did not improve the antibiofouling property. These results highlight the importance of antimicrobial property of the coating for biofouling prevention and show antiscaling materials can be effective not only as an additive to the feed but also as a coating on the membrane to reduce scaling.
Carbon dioxide storage combined with enhanced oil recovery (CCS-EOR) is an important approach for reducing greenhouse gas emissions. We use pore-scale imaging to help understand CO2 storage and oil recovery during CCS-EOR at immiscible and near-miscible CO2 injection conditions. We study in situ immiscible CO2 flooding in an oil-wet reservoir rock at elevated temperature and pressure using X-ray micro-tomography. We observe the predicted, but hitherto unreported, three-phase wettability order in strongly oil-wet rocks, where water occupies the largest pores, oil the smallest, while CO2 occupies pores of intermediate size. We investigate the pore occupancy, existence of CO2 layers, recovery and CO2 trapping in the oil-wet rock at immiscible conditions and compare to the results obtained on the same rock type under slightly more weakly oil-wet near-miscible conditions, with the same wettability order. CO2 spreads in connected layers at near-miscible conditions, while it exists as disconnected ganglia in medium-sized pores at immiscible conditions. Hence, capillary trapping of CO2 by oil occurs at immiscible but not at near-miscible conditions. Moreover, capillary trapping of CO2 by water is not possible in both cases since CO2 is more wetting to the rock than water. The oil recovery by CO2 injection alone is reduced at immiscible conditions compared to near-miscible conditions, where low gas-oil capillary pressure improves microscopic displacement efficiency. Based on these results, to maximize the amount of oil recovered and CO2 stored at immiscible conditions, a water-alternating-gas injection strategy is suggested, while a strategy of continuous CO2 injection is recommended at near-miscible conditions.
Parallel-group thorough QT/QTc studies focus on the change of QT/QTc values at several time-matched points from a pre-treatment day (baseline) to a post-treatment day for different groups of treatment. The International Council for Harmonisation (ICH) E14 stresses that QTc prolongation beyond a threshold represents high cardiac risk and calls for a test on the largest time-matched treatment effect (QTc prolongation). QT/QTc analysis usually assumes a jointly multivariate normal (MVN) distribution of pre-treatment and post-treatment QT/QTc values, with a blocked compound symmetry covariance matrix. Existing methods use an analysis of covariance model including day-averaged baseline as a covariate to deal with the MVN model. However, the analysis of covariance model tends to underestimate the variation of the estimator for treatment effects, resulting in the inflation of empirical type I error rate when testing whether the largest QTc prolongation is beyond a threshold. In this paper, we propose two new methods to estimate the time-matched treatment effects under the MVN model, including maximum likelihood estimation and ordinary-least-square-based two-stage estimation. These two methods take advantage of the covariance structure and are asymptotically efficient. Based on these estimators, powerful tests for QT/QTc prolongation are constructed. Simulation shows that the proposed estimators have smaller mean square error, and the tests can control the type I error rate with high power. The proposed methods are applied on testing the carryover effect of diltiazem to inhibit dofetilide in a randomized phase 1 trial.
