Novel worm-like Ag/ZnO core–shell heterostructural composites were fabricated using a two-step chemical method. As-prepared silver nanowires were soaked in a solution of zinc acetate and ...triethanolamine to form worm-like Ag/ZnO core–shell composites under ultrasonic irradiation. Samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy, and UV–vis spectrophotometer. The results show that the core–shell composites are composed of single-crystal Ag nanowires serving as the core, on which dense ZnO particles grow as the shell. The surface plasmon absorption band of Ag/ZnO composites is distinctly broadened and red shifted to monometallic Ag nanowires. The PL intensity of Ag/ZnO heterostructural composites varies and has the minimum intensity for the sample prepared with Ag of 2.8 atom %. Moreover, photocatalytic tests show that the Ag/ZnO composites exhibit higher photocatalytic activity compared to pure ZnO particles.
• Microbes detoxify arsenate by reduction and efflux of arsenite. Plants have a high capacity to reduce arsenate, but arsenic efflux has not been reported. • Tomato (Lycopersicon esculentum) and rice ...(Oryza sativa) were grown hydroponically and supplied with 10 pM arsenate or arsenite, with or without phosphate, for 1-3 d. The chemical species of As in nutrient solutions, roots and xylem sap were monitored, roles of microbes and root exudates in As transformation were investigated and efflux of As species from tomato roots was determined. • Arsenite remained stable in the nutrient solution, whereas arsenate was rapidly reduced to arsenite. Microbes and root exudates contributed little to the reduction of external arsenate. Arsenite was the predominant species in roots and xylem sap. Phosphate inhibited arsenate uptake and the appearance of arsenite in the nutrient solution, but the reduction was near complete in 24 h in both -P- and +P-treated tomato. Phosphate had a greater effect in rice than tomato. Efflux of both arsenite and arsenate was observed; the former was inhibited and the latter enhanced by the metabolic inhibitor carbonylcyanide m-chlorophenylhydrazone. • Tomato and rice roots rapidly reduce arsenate to arsenite, some of which is actively effluxed to the medium. The study reveals a new aspect of As metabolism in plants.
We evaluated the effectiveness of lime and red mud (by-product of aluminium manufacturing) to reduce metal availability to
Festuca rubra and to allow re-vegetation on a highly contaminated ...brown-field site. Application of both lime and red mud (at 3 or 5%) increased soil pH and decreased metal availability.
Festuca rubra failed to establish in the control plots, but grew to a near complete vegetative cover on the amended plots. The most effective treatment in decreasing grass metal concentrations in the first year was 5% red mud, but by year two all amendments were equally effective. In an additional pot experiment, P application in combination with red mud or lime decreased the Pb concentration, but not total uptake of Pb in
Festuca rubra compared to red mud alone. The results show that both red mud and lime can be used to remediate a heavily contaminated acid soil to allow re-vegetation.
Red mud was effective in immobilising heavy metals in soil.
Human activity has a profound influence on river discharges, hydrological extremes and water-related hazards. In this study, we compare the results of five state-of-the-art global hydrological models ...(GHMs) with observations to examine the role of human impact parameterizations (HIP) in the simulation of mean, high- and low-flows. The analysis is performed for 471 gauging stations across the globe for the period 1971-2010. We find that the inclusion of HIP improves the performance of the GHMs, both in managed and near-natural catchments. For near-natural catchments, the improvement in performance results from improvements in incoming discharges from upstream managed catchments. This finding is robust across the GHMs, although the level of improvement and the reasons for it vary greatly. The inclusion of HIP leads to a significant decrease in the bias of the long-term mean monthly discharge in 36%-73% of the studied catchments, and an improvement in the modeled hydrological variability in 31%-74% of the studied catchments. Including HIP in the GHMs also leads to an improvement in the simulation of hydrological extremes, compared to when HIP is excluded. Whilst the inclusion of HIP leads to decreases in the simulated high-flows, it can lead to either increases or decreases in the low-flows. This is due to the relative importance of the timing of return flows and reservoir operations as well as their associated uncertainties. Even with the inclusion of HIP, we find that the model performance is still not optimal. This highlights the need for further research linking human management and hydrological domains, especially in those areas in which human impacts are dominant. The large variation in performance between GHMs, regions and performance indicators, calls for a careful selection of GHMs, model components and evaluation metrics in future model applications.
This paper reviews the recent advances in understanding of metal removal from contaminated soils, using either hyperaccumulator plants, or high biomass crop species after soil treatment with ...chelating compounds. Progress has been made at the physiology and molecular level regarding Zn and Ni uptake and translocation in some hyperaccumulators. It is also known that natural hyperaccumulators do not use rhizosphere acidification to enhance their metal uptake. Recently, it has been found that some natural hyperaccumulators proliferate their roots positively in patches of high metal availability. In contrast, non-accumulators actively avoid these areas, and this is one of the mechanisms by which hyperaccumulators absorb more metals when grown in the same soil. However, there are few studies on the exudation and persistence of natural chelating compounds by these plants. It is thought that rhizosphere microorganisms are not important for the hyperaccumulation of metals from soil. Applications of chelates have been shown to induce large accumulations of metals like Pb, U and Au in the shoots of nonhyperaccumulators, by increasing metal solubility and root to shoot translocation. The efficiency of metal uptake does vary with soil properties, and a full understanding of the relative importance of mass flow and diffusion in the presence and absence of artificial chelates is not available. To successfully manipulate and optimise future phytoextraction technologies, it is argued that a fully combined understanding of soil supply and plant uptake is needed.
The effects of microstructure, texture evolution and strengthening mechanisms on mechanical properties of 3003 aluminum alloy during cryogenic rolling (CR) and room temperature rolling (RTR) ...processing were investigated by electron backscatter diffraction, transmission electron microscopy and X-ray diffraction. The results show that the CR processing can significantly decrease the size of sub-grains and second-phase particles, and increase the dislocation density of the 3003 aluminum alloy. During the CR and RTR processing, the initial Cube and R-Cube textures are gradually rotated into the β-fiber texture. The CR processing can obviously delay the texture evolution from initial Cube texture to β-fiber texture during rolling. A significant enhancement in the yield strength, ultimate tensile strength and elongation of the 3003 aluminum alloy after the CR processing is obtained comparing with the RTR processing. This can be explained by the contribution of dislocation strengthening and grain refinement strengthening.
•Microstructure, texture evolution and strengthening mechanisms in 3003 aluminum alloy during CR and RTR were investigated.•CR processing can refine the size of sub-grains grains and increase the dislocation density.•CR processing can delay the texture evolution from initial cube texture to β-fiber texture.•CR processing can enhanced the YS, UTS and EL of CR samples compared with the RTR samples.
$\bullet$Arabidopsis halleri is a well-known zinc (Zn) hyperaccumulator, but its status as a cadmium (Cd) hyperaccumulator is less certain. Here, we investigated whether A. halleri can ...hyperaccumulate Cd and whether Cd is transported via the Zn pathway.$\bullet$Growth and Cd and Zn uptake were determined in hydroponic experiments with different Cd and Zn concentrations. Short-term uptake and root-to-shoot transport were measured with radioactive109Cd and65Zn labelling.$\bullet$A. halleri accumulated >$1000 mg Cd kg^{-1}$in shoot dry weight at external Cd concentrations$\geq 5 \mu M$, but the short-term uptake rate of109Cd was much lower than that of65Zn. Zinc inhibited short-term109Cd uptake kinetics and root-to-shoot translocation, as well as long-term Cd accumulation in shoots. Uptake of109Cd and65Zn were up-regulated, respectively, by low iron (Fe) or Zn status. A. halleri was much less tolerant to Cd than to Zn.$\bullet$We conclude that A. halleri is able to hyperaccumulate Cd partly, at least, through the Zn pathway, but the mechanisms responsible for cellular Zn tolerance cannot detoxify Cd effectively.
Abstract
Spin-valley locking in monolayer transition metal dichalcogenides has attracted enormous interest, since it offers potential for valleytronic and optoelectronic applications. Such an exotic ...electronic state has sparsely been seen in bulk materials. Here, we report spin-valley locking in a Dirac semimetal BaMnSb
2
. This is revealed by comprehensive studies using first principles calculations, tight-binding and effective model analyses, angle-resolved photoemission spectroscopy measurements. Moreover, this material also exhibits a stacked quantum Hall effect (QHE). The spin-valley degeneracy extracted from the QHE is close to 2. This result, together with the Landau level spin splitting, further confirms the spin-valley locking picture. In the extreme quantum limit, we also observed a plateau in the
z
-axis resistance, suggestive of a two-dimensional chiral surface state present in the quantum Hall state. These findings establish BaMnSb
2
as a rare platform for exploring coupled spin and valley physics in bulk single crystals and accessing 3D interacting topological states.
This paper aimed to investigate the effect of long non-coding RNA TUG1 (lncRNA TUG1) on cell proliferation, as well as cell migration in pancreatic cancer.
The mRNA levels of Taurine-up-regulated ...gene 1 (TUG1) in three kinds of pancreatic cancer cells BxPC3, PaTu8988 and SW1990 was detected by RT-qPCR. Meantime, RT-qPCR was used to examine the mRNA levels of TUG1 in 20 cases of human pancreatic cancer tissues and its para-carcinoma tissues. pCDH-TUG1 plasmid and its empty plasmid pCDH were transfected into BxPC3 and PaTu8988 cells to up-regulate TUG1 expression. siRNA targeting TUG1 and the control siRNA were transfected into SW1990 cells to down-regulate TUG1 expression. Cell clone formation and CCK-8 assay were used to detect the cell proliferation capacity. Transwell assay was used to evaluate cell migration capacity. Western blot was applied to examine the protein expressions of MMP2, MMP9, E-cadherin, Smad 2, Smad 3, p-Smad 2, p-Smad 3, TGF-β and TGF-βR. RT-qPCR was used to detect the levels of MMP2 and MMP9.
The results showed that TUG1 was differentially expressed in the three kinds of pancreatic cancer cells, among which the expression level of SW1990 was relatively high, and the expression levels of BxPC3 and PaTu8988 were relatively low. TUG1 had more expression in pancreatic cancer tissues than that in para-carcinoma tissues. After the up-regulation of TUG1, cell proliferation and migration capacities were increased, protein levels of MMP2 and MMP9 were increased and protein level of E-cadherin was declined. Conversely, after down-regulation of TUG1 expression, cell proliferation and migration capacities were weakened, protein levels of MMP2 and MMP9 were decreased and protein level of E-cadherin was increased. In addition, over-expressed TUG1 could promote Smad2 and Smad3 phosphorylation, but Smad2 and Smad3 phosphorylation were weakened after down-regulated expression of TUG1. The protein expression of TGF-β and TGF-β receptor were more in the TUG1 overexpression group than that in the control group, while the result was just opposite after TUG1 expression was down-regulated.
These data suggest that lncRNA TUG1 may enhance the proliferation and migration of pancreatic cancer cells through EMT pathway.
Performing laparoscopic myomectomy for an intracervical myoma, especially a single giant myoma, is challenging. Only skilled surgeons attempt this operation. Surgeons frequently encounter cases of ...massive intraoperative bleeding, difficulty suturing the cervical incision, risk of injuring the neighbouring tissues, haematoma formation and conversion to laparotomy or hysterectomy. We previously developed a the technique of loop ligation of the pseudocapsule and have been using it to treat sizeable intracervical myomas laparoscopically. Its advantages include less blood loss, lower risk of injuries to the neighbouring tissues, maintenance of the cervical canal and sparing of the pseudocapsule. This technique is safe and feasible, and facilitates fertility.
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The loop ligation technique is safe and feasible for laparoscopic myomectomy involving intracervical myomas.
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The loop ligation technique is safe and feasible for laparoscopic myomectomy involving intracervical myomas.
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