In this communication, a high-gain substrate-integrated waveguide (SIW) filtering patch antenna with low H-plane cross-polarization (cross-pol) and controllable radiation nulls is proposed. The ...antenna is composed of a radiation patch integrated with three pairs of shorting pins and a single layer SIW cavity with two transverse slots. The shorting pins loaded on the patch can improve the gain and reduce the H-plane cross-pol of the antenna. The long slot on the middle layer can not only split the TE 110 -mode resonator into two half-mode resonators but also generate magnetic coupling between half-mode resonators and the patch. Another short slot achieves mixed electric and magnetic coupling between the left half-mode resonator and the patch that introducing controllable radiation nulls to improve the selectivity. By adjusting the parameters of the short slot, the positions of two radiation nulls can be easily controlled. Finally, one prototype filtering antenna is fabricated and measured for demonstration. Experimental results show that the proposed SIW filtering antenna achieves a high gain of 9 dBi with only one radiator and has the merit of high-frequency selectivity as well as low H-plane cross-pol of lower than −43 dB.
At present, the remediation of heavy-metal polluted soil is a considerable problem. In this study, in situ immobilization field experiments were conducted by planting rice (Oryza sativa L.) in Cd ...contaminated paddy soil to determine the optimal remediation mode that would reduce the accumulation of Cd in brown grain. Sepiolite and palygorskite were utilized as amendments, while ordinary and low Cd-accumulating rice cultivars were selected as model plants. The remediation effects of the amendments on the soil and rice were investigated and the potential immobilization mechanisms were analyzed using X-ray diffraction and X-ray photoelectron spectroscopy. The application of sepiolite and palygorskite was found to increase the pH value of the paddy soil, by varying amounts, and significantly reduce the HCl, TCLP, CaCl2, and NH4OAc-extractable Cd concentrations resulting in a notable decrease in the Cd concentration in brown rice. Both sepiolite and palygorskite were found to reduce exchangeable Cd concentrations and increase the carbonate-bound and residual fractions in paddy soil. Precipitation of Cd as carbonates or hydroxides and surface complexation were the main immobilization mechanisms for sepiolite and palygorskite. The concentration of Cd in brown rice of the low Cd-accumulating cultivar from the control plot was 0.72mg·kg−1. Sepiolite treatment reduced the value to 0.18mg·kg−1 below the maximum levels reported by Codex Stan 193-1995 and the national standard of China. It was concluded that chemical immobilization combined with crop cultivar selection could be a suitable proposal for crop safety regulation and sustainable agriculture.
Combination of chemical immobilization and low Cd accumulating rice cultivar.
In situ chemical immobilization can significantly decrease the bioavailability and bioaccessibility of cadmium in paddy soil. Meanwhile, selection and breeding of low Cd accumulating cultivars is an environmentally friendly and cost effective method for reducing the risk of contamination from Cd in food. The results of this study suggested that safer food production was more likely to be achievable by combining low Cd accumulating cultivars with in situ immobilizing agent amendment of soils. Display omitted
•Sepiolite and palygorskite significantly reduced phytoavailable Cd in paddy soils.•Precipitation and surface complexation were main immobilization mechanisms.•Combination of chemical immobilization and low accumulating cultivar was recommended.
Powder spreading process is to use a spreader such as blade or roller to spread powder layers for subsequent fusion in powder bed fusion additive manufacturing. In this work, the effects of various ...spreader geometries on powder spreading are examined by discrete element method (DEM). The results show that a compact region in the powder pile exists. Round and inclined surfaces of blade spreaders allow more particles in the compact region to be deposited compared with vertical blades, thus the powder layer formed is denser. However, they exert larger forces on the underlying part. Inhomogeneity of powder layers is caused by particle burst phenomenon, which is due to particle motion conflict in the compact region rather than large forces. Roller system has largest particle motion conflict thus powder layers formed are sparse and inhomogeneous with small layer gaps. Size segregation in blade systems is not as severe as roller systems.
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•Powder spreading process with different spreaders is simulated by DEM.•Round and inclined blades deposit more powders than vertical blades.•Round and inclined blades exert larger forces on the underlying part.•Large layer gap has better homogeneity and smaller force fluctuation.•Round blade system has the least size segregation.
Metal–organic frameworks (MOFs) have emerged as porous solids of a superior type for the fabrication of membranes. However, it is still challenging to prepare a uniformly dispersed robust MOF hybrid ...membrane. Herein, we propose a simple and powerful strategy, namely, coordination‐driven in situ self‐assembly, for the fabrication of MOF hybrid membranes. On the basis of the coordination interactions between metal ions and ligands and/or the functional groups of the organic polymer, this method was confirmed to be feasible for the production of a stable membrane with greatly improved MOF‐particle dispersion in and compatibility with the polymer, thus providing outstanding separation ability. As an experimental proof of concept, a high‐quality ZIF‐8/PSS membrane was fabricated that showed excellent performance in the nanofiltration and separation of dyes from water.
Mopping up the mess: A hybrid membrane composed of the metal–organic framework (MOF) ZIF‐8 and poly(sodium 4‐styrenesulfonate) was prepared by a coordination‐driven in situ self‐assembly method. The MOF particles were well‐dispersed in the polymer in the resulting stable membrane (see picture), which showed excellent performance in the nanofiltration and separation of dyes from water.
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•The light weight YZFM has excellent flexibility and strength (6.49 MPa) at 1200 °C.•The YZFM has excellent high temperature resistance and low thermal conductivity.•The YZFM have ...better acoustic absorption performance than commercial materials.
At high temperatures, lightweight ceramic and aerogel materials have serious problems such as volume shrinkage, increased density, loss of flexibility, and decreased thermal insulation performances. The research on high-performance, lightweight, and flexible materials, which can meet the requirements of high-temperature applications, is a challenging topic in the industry. In this work, we developed a defective fluorite phase Y2Zr2O7 flexible fibrous membrane (YZFM) material which has excellent thermal stability, no phase change until 1200 °C, and excellent flexibility until 1200 °C. The dense single fiber structure results in the tensile strength of the YZFM as high as 8.27 MPa. The low density (44 mg/cm3), high porosity (99.2%), and excellent heat radiation reflectivity (750–2500 nm: Avg. 96.34%) endow the YZFM with outstanding thermal insulation performance (the thermal conductivity: 38 mW m−1 K−1). The 30 mm thick YZFM can reduce the high temperature of 1260 °C to 185 °C. The anisotropic layered structure makes YZFM have better acoustic absorption performance than commercial materials. These robust performances make our YZFM suitable for fields with strict requirements on material usage conditions, such as aerospace and cutting-edge industries.
2D transition metal dichalcogenides materials are explored as potential surface‐enhanced Raman spectroscopy substrates. Herein, a systematic study of the Raman enhancement mechanism on distorted 1T ...(1T′) rhenium disulfide (ReS2) nanosheets is demonstrated. Combined Raman and photoluminescence studies with the introduction of an Al2O3 dielectric layer unambiguously reveal that Raman enhancement on ReS2 materials is from a charge transfer process rather than from an energy transfer process, and Raman enhancement is inversely proportional while the photoluminescence quenching effect is proportional to the layer number (thickness) of ReS2 nanosheets. On monolayer ReS2 film, a strong resonance‐enhanced Raman scattering effect dependent on the laser excitation energy is detected, and a detection limit as low as 10−9m can be reached from the studied dye molecules such as rhodamine 6G and methylene blue. Such a high enhancement factor achieved through enhanced charge interaction between target molecule and substrate suggests that with careful consideration of the layer‐number‐dependent feature and excitation‐energy‐related resonance effect, ReS2 is a promising Raman enhancement platform for sensing applications.
Here the Raman enhancement mechanism on distorted 1T ReS2 nanosheets is demonstrated, where combined Raman and photoluminescence studies with the introduction of an Al2O3 dielectric layer unambiguously reveal that Raman enhancement on ReS2 materials is from a charge transfer process rather than from an energy transfer process.
Many physical and social systems are best described by networks. And the structural properties of these networks often critically determine the properties and function of the resulting mathematical ...models. An important method to infer the correlations between topology and function is the detection of community structure, which plays a key role in the analysis, design, and optimization of many complex systems. The nonnegative matrix factorization has been used prolifically to that effect in recent years, although it cannot guarantee balanced partitions, and it also does not allow a proactive computation of the number of communities in a network. This indicates that the nonnegative matrix factorization does not satisfy all the nonnegative low-rank approximation conditions. Here we show how to resolve this important open problem by optimizing the identifiability of community structure. We propose a new form of nonnegative matrix decomposition and a probabilistic surrogate learning function that can be solved according to the majorization-minimization principle. Extensive in silico tests on artificial and real-world data demonstrate the efficient performance in community detection, regardless of the size and complexity of the network.
SUMMARY
High‐affinity phosphate (Pi) transporters (PHTs) PHT1;1 and PHT1;4 are necessary for plant root Pi uptake especially under Pi‐deficient conditions, but how their protein stability is ...modulated remains elusive. Here, we identified a Ttransfer DNA insertion mutant of Sorting Nexin1 (SNX1), which had more Pi content and less anthocyanin accumulation than the wild type under deficient Pi. By contrast, the snx1‐2 mutant displayed higher sensitivity to exogenous arsenate in terms of seed germination and root elongation, revealing higher Pi uptake rates. Further study showed that SNX1 could co‐localize and interact with PHT1;1 and PHT1;4 in vesicles and at the plasma membrane. Genetic analysis showed that increased Pi content in the snx1‐2 mutant under low Pi conditions could be extensively compromised by mutating PHT1;1 in the double mutant snx1‐2 pht1;1, revealing that SNX1 is epistatic to PHT1;1. In addition, SNX1 negatively controls PHT1;1 protein stability; therefore, PHT1;1 protein abundance in the plasma membrane was increased in the snx1‐2 mutant compared with the wild type under either sufficient or deficient Pi. Together, our study (i) identifies SNX1 as a key modulator of the plant response to low Pi and (ii) unravels its role in the modulation of PHT1;1 protein stability, PHT1;1 accumulation at the plasma membrane, and root Pi uptake.
Significance Statement
High‐affinity phosphate (Pi) transporters (PHTs) PHT1;1 and PHT1;4 are necessary for plant root Pi uptake, but how their protein stability is modulated remains elusive. Our study (i) identifies Sorting Nexin1 as a key modulator of the plant response to low Pi and (ii) unravels its role in the modulation of PHT1;1 protein stability, PHT1;1 accumulation at the plasma membrane, and root Pi uptake.
Glycogen synthase kinase-3β (GSK-3β) acts as a negative regulator of NF-E2 related factor 2 (Nrf2) by inducing Nrf2 degradation and nuclear export. Our previous study demonstrated that the flavonoid ...hyperoside elicits cytoprotection against oxidative stress by activating the Keap1-Nrf2-ARE signaling pathway, thus increasing the expression of antioxidant enzymes, such as heme oxygenase-1 (HO-1), superoxide dismutase (SOD) and catalase. However, the role of GSK-3β in hyperoside-mediated Nrf2 activation is unclear. Here, we demonstrate that in a normal human hepatocyte cell line, (L02), hyperoside is capable of inducing the phosphorylation of GSK-3β at Ser9 without affecting the protein levels of GSK-3β and its phosphorylation at Thr390. Lithium chloride (LiCl) and short interfering RNA (siRNA)-mediated inhibition of GSK-3β significantly enhanced the ability of hyperoside to protect L02 liver cells from H2O2-induced oxidative damage, leading to increased cell survival shown by the maintenance of cell membrane integrity and elevated levels of glutathione (GSH), one of the endogenous antioxidant biomarkers. Further study showed that LiCl and siRNA-mediated inhibition of GSK-3β increased hyperoside-induced HO-1 expression, and the effect was dependent upon enhanced Nrf2 nuclear translocation and gene expression. These activities were followed by ARE-mediated transcriptional activation in the presence of hyperoside, which was abolished by the transfection of the cells with Nrf2 siRNA. Furthermore, the siRNA-mediated inhibition of Keap1 also enhanced hyperoside-induced Nrf2 nuclear accumulation and HO-1 expression, which was relatively smaller than the effects obtained from GSK-3β siRNA administration. Moreover, Keap1 siRNA administration alone had no significant effect on the phosphorylation and protein expression of GSK-3β. Collectively, our data provide evidence that hyperoside attenuates H2O2 -induced L02 cell damage by activating the Nrf2-ARE signaling pathway through both an increase in GSK-3β inhibitory phosphorylation at Ser9 and an inhibition of Keap1 and that hyperoside-mediated GSK-3β inhibition exhibits more significant effects.
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