GLABRA 2 regulates ETHYLENE OVERPRODUCER 1 accumulation during nutrient deficiency-induced root hair growth.

Root hairs (RHs), extensive structures of root epidermal cells, are important for plant nutrient acquisition, soil anchorage, and environmental interactions. Excessive production of the phytohormone ethylene (ET) leads to substantial root hair growth, manifested as tolerance to plant nutrient deficiencies. However, the molecular basis of ET production during root hair growth in response to nutrient starvation remains unknown. Herein, we found that a critical transcription factor, GLABRA 2 (GL2), inhibits ET production during root hair growth in Arabidopsis (Arabidopsis thaliana). GL2 directly binds to the promoter of the gene encoding ET OVERPRODUCER 1 (ETO1), one of the most important ET-production-regulation factors, in vitro and in vivo, and then regulates the accumulation and function of ETO1 in root hair growth. The GL2-regulated-ETO1 module is required for promoting root hair growth under nitrogen, phosphorus, or potassium deficiency. Genome-wide analysis revealed numerous genes, such as ROOT HAIR DEFECTIVE 6-LIKE 4, ETHYLENE-INSENSITIVE 3-LIKE 2, ROOT HAIR SPECIFIC 13, are involved in the GL2-regulated-ETO1 module. Our work reveals a key transcription mechanism in the control of ET production during root hair growth under three major nutrient deficiencies.

Actin depolymerizing factor ADF7 inhibits actin bundling protein VILLIN1 to regulate root hair formation in response to osmotic stress in Arabidopsis.

Actin cytoskeleton is essential for root hair formation. However, the underlying molecular mechanisms of actin dynamics in root hair formation in response to abiotic stress are largely undiscovered. Here, genetic analysis showed that actin-depolymerizing protein ADF7 and actin-bundling protein VILLIN1 (VLN1) were positively and negatively involved in root hair formation of Arabidopsis respectively. Moreover, RT-qPCR, GUS staining, western blotting, and genetic analysis revealed that ADF7 played an important role in inhibiting the expression and function of VLN1 during root hair formation. Filament actin (F-actin) dynamics observation and actin pharmacological experiments indicated that ADF7-inhibited-VLN1 pathway led to the decline of F-actin bundling and thick bundle formation, as well as the increase of F-actin depolymerization and turnover to promote root hair formation. Furthermore, the F-actin dynamics mediated by ADF7-inhibited-VLN1 pathway was associated with the reactive oxygen species (ROS) accumulation in root hair formation. Finally, ADF7-inhibited-VLN1 pathway was critical for osmotic stress-induced root hair formation. Our work demonstrates that ADF7 inhibits VLN1 to regulate F-actin dynamics in root hair formation in response to osmotic stress, providing the novel evidence on the F-actin dynamics and their molecular mechanisms in root hair formation and in abiotic stress.

Au nanoparticles decorated ß-Bi2O3 as highly-sensitive SERS substrate for detection of methylene blue and methyl orange.

In this work, Au/Bi2O3 was synthesized by loading Au nanoparticles (NPs) onto ß-Bi2O3 by a simple solution reduction method. ß-Bi2O3 was synthesized by a precipitation-thermal decomposition procedure, which results in significantly improved SERS detection limits down to 10-9 M for methylene blue (MB) and 10-7 M for methyl orange (MO) as probe molecules, comparable to those reported for the best semiconductor SERS substrates. In particular, further deposition of Au NPs (5.20% wt%) onto ß-Bi2O3 results in a two-order-of-magnitude enhancement in detection sensitivity, achieving a detection limit of 10-11 M for MB and 10-9 M for MO. Under ultraviolet/visible irradiation, the Au/Bi2O3 hybrids substrate exhibits superior self-cleaning ability due to its photocatalytic degradation ability which can be applied repeatedly to the detection of pollutants. The advanced composite substrate simultaneously achieved ultra-low mass loading of Au NPs, outstanding detection performance, good reproducibility, high stability and self-cleaning ability. The development strategy of low load noble metal coupled high performance semiconductor ß-Bi2O3 to obtain nano-hybrid materials provides a method to balance SERS sensitivity, cost effectiveness and operational stability, and can be synthesized in large quantities, which is a key step towards commercialization and has good reliability prospects.

Actin Depolymerization Factor ADF1 Regulated by MYB30 Plays an Important Role in Plant Thermal Adaptation.

Actin filaments are essential for plant adaptation to high temperatures. However, the molecular mechanisms of actin filaments in plant thermal adaptation remain unclear. Here, we found that the expression of Arabidopsis actin depolymerization factor 1 (AtADF1) was repressed by high temperatures. Compared with wild-type seedlings (WT), the mutation of AtADF1 and the overexpression of AtADF1 led to promoted and inhibited plant growth under high temperature conditions, respectively. Further, high temperatures induced the stability of actin filaments in plants. Compared with WT, Atadf1-1 mutant seedlings showed more stability of actin filaments under normal and high temperature conditions, while the AtADF1 overexpression seedlings showed the opposite results. Additionally, AtMYB30 directly bound to the promoter of AtADF1 at a known AtMYB30 binding site, AACAAAC, and promoted the transcription of AtADF1 under high temperature treatments. Genetic analysis further indicated that AtMYB30 regulated AtADF1 under high temperature treatments. Chinese cabbage ADF1 (BrADF1) was highly homologous with AtADF1. The expression of BrADF1 was inhibited by high temperatures. BrADF1 overexpression inhibited plant growth and reduced the percentage of actin cable and the average length of actin filaments in Arabidopsis, which were similar to those of AtADF1 overexpression seedlings. AtADF1 and BrADF1 also affected the expression of some key heat response genes. In conclusion, our results indicate that ADF1 plays an important role in plant thermal adaptation by blocking the high-temperature-induced stability of actin filaments and is directly regulated by MYB30.

Synthesis of the Red-Emitting (Ba, Ca)2ScAlO5:Eu3+ Phosphors with Photoluminescence Properties.

The light-emitting diodes (LED) are regarded as one of the most promising devices for inexpensive and widely used illumination; in particular, they are highly dependent on the development of red-emitting phosphors. Herein, we developed two types of red-emitting (Ba, Ca)2ScAlO5:Eu3+ multiple excitations phosphors (λex = 255-465 nm) via freeze-drying followed by calcination. Powder X-ray diffraction and NMR results point out that they have hexagonal space group P63/mmc (194), and the structural framework is composed of multi-coordinated Al3+-O2- polyhedron and Sc3+-O2- polyhedron. In addition, the valence state of europium (Eu3+) is confirmed by X-ray photoelectron spectroscopy characterization. Investigation on the photoluminescence properties showed that the photoluminescence process of (Ba, Ca)2ScAlO5:Eu3+ is attributable to the charge transfer band of Eu-O and abundant spectral terms of Eu3+. The α-(Ba, Ca)2ScAlO5:Eu3+ and ß-(Ba, Ca)2ScAlO5:Eu3+ exhibited red emission under 465 and 395 nm excitation, respectively. The PL spectra and decay curves explain the intrinsic photoluminescence mechanism. The strongest emission peaks of the red-emitting α-(Ba, Ca)2ScAlO5:Eu3+ and ß-(Ba, Ca)2ScAlO5:Eu3+ phosphors are at 615 and 619 nm, respectively, exhibiting a high fluorescence of 64 and 67% under the temperature of 423 K (150 °C). Further exploration of the red-emitting phosphors would provide a variety of choices for the design of red LEDs and white LEDs for the solid-state lighting system.

Unidirectional water transport on a two-dimensional hydrophilic channel with anisotropic superhydrophobic barriers.

Many creatures have a unique anisotropic structure and special wettability on their skins, presenting intriguing water transporting properties. Inspired by the biosphere, a two-dimensional titanium dioxide-based hydrophilic channel possessing anisotropic superhydrophobic barriers was synthesized. This channel demonstrates unidirectional water transporting properties. When water is injected into the channel, fluid tends to spread in a specific direction. An asymmetric spreading resistance is generated by the different interaction modes between the liquid and superhydrophobic barriers. The superhydrophobic barriers are designed as two main styles: line and curve. As for line barriers, the included angle between barrier and horizontal is the key parameter for the unidirectional water transporting ability whereas, for curve barriers, the radius is an important variable. The best design scheme for unidirectional water transporting properties could be found by varying the parameters of these two types of barriers in the channel. Overall, this study is expected to have a significant implication in the water transporting field.

Free-standing NiCoSe2 nanostructure on Ni foam via electrodeposition as high-performance asymmetric supercapacitor electrode.

Designing a high-energy-density and power-density electrode for supercapacitors has become an increasingly important concept in the energy storage community. In this article, NiCoSe2 nanostructures were electrodeposited on nickel (Ni) foam and directly used as electrodes for supercapacitors. The effect on the morphology and electrochemical performance of NiCoSe2 prepared under different scan rates was measured through scanning electron microscopy and various electrochemical measurements. The resultant NiCoSe2 prepared with 5 mV s-1 exhibits a cross-linked porous nanostructure and a high specific capacitance of 2185 F g-1 at a current density of 1 A g-1. Taking advantage of these features, an ASC is constructed by using NiCoSe2 on Ni foam as the positive electrode and an active carbon electrode as the negative electrode with 3 M KOH as the electrolyte. The ASC displays a high-energy density of 41.8 Wh kg-1, an ultrahigh power output of 8 kW kg-1, as well as a long cycling life (91.4% capacity retention after 10 000 cycles). The excellent electrochemical performance makes the porous NiCoSe2 nanostructures a promising alternative in energy storage devices.

Controlled synthesis of Zeolite adsorbent from low-grade diatomite: A case study of self-assembled sodalite microspheres.

Highly efficient and sustainable conversion technologies to generate uniform sodalite (Na8(AlSiO4)6(OH)2) zeolite microspheres with low-grade waste natural diatomite as raw materials via a solution-mediated crystallization route were developed in the present study. The synthesis process can be considered as an in-situ zeolitization of diatomite precursor without involving any mesoscale template and any post-synthetic modification. The mass ratios of diatomite and AlCl3·6H2O have remarkable effect on the morphology, crystal structure and porosity of sodalite zeolite product. The preferred sodalite microspheres with uniform mesoporous of size 3.5-5.5 nm and large surface area of 162.5 m2/g exhibit well removal performance for heavy metal ions (Pb(II), Cd(II), Zn(II), and Cu(II)), with the highest adsorption abilities for Pb(II) ions of 365 mg/g. In addition, the effect of contact time, initial ion concentration, competitive adsorption and solution pH were evaluated. The removal performance results from synergistic effects of dominating cation-exchange and additional surface chemisorption. The study may broadly help unveil chemical control reactions of the zeolitization processes of diatomite, and thus facilitates the development of promising zeolite materials for the use in natural and engineered aquatic environments by recycling waste diatomite resources.

Goethite Quantum Dots as Multifunctional Additives for Highly Efficient and Stable Perovskite Solar Cells.

Minimization of defects and ion migration in organic-inorganic lead halide perovskite films is desirable for obtaining photovoltaic devices with high power conversion efficiency (PCE) and long-term stability. However, achieving this target is still a challenge due to the lack of efficient multifunctional passivators. Herein, to address this issue, n-type goethite (FeOOH) quantum dots (QDs) are introduced into the perovskite light-absorption layer for achieving efficient and stable perovskite solar cells (PSCs). It is found that the iron, oxygen, and hydroxyl of FeOOH QDs can interact with iodine, lead, and methylamine, respectively. As a result, the crystallization kinetics process can be retarded, thereby resulting in high quality perovskite films with large grain size. Meanwhile, the trap states of perovskite can be effectively passivated via interaction with the under-coordinated metal (Pb) cations, halide (I) anions on the perovskite crystal surface. Consequently, the PSCs with FeOOH QDs achieve a high efficiency close to 20% with negligible hysteresis. Most strikingly, the long-term stability of PSCs is significantly enhanced. Furthermore, compared with the CH3 NH3 PbI3 -based device, a higher PCE of 21.0% is achieved for the device assembled with a Cs0.05 FA0.81 MA0.14 PbBr0.45 I2.55 perovskite layer.

Fabrication and Emission Performance of Nanostructured Re-W Matrix Impregnated Cathodes.

In this study, rhenium-tungsten mixed particles with different content of rhenium have been prepared by spray-drying method followed by hydrogen reduction. Using such particles, the cathodes have been prepared by powder metallurgy followed by impregnating BaO, CaO, and Al2O3 with 4:1:1 molar ratio. After proper activation, electron emission test is performed in standard parallel-plate diode configuration. The emission results reveal that the Re-W matrix cathode containing 75% rhenium has the highest direct current emission density of 11.67 A/cm2 at 1000 °C. The work function of Re-W matrices has been investigated by density functional theory method in the frame of the generalized gradient approximation (GGA). The theoretical calculation results indicate that the work function of the matrix has limited contribution to the emission current density of Re-W matrix dispenser cathode. The in situ AES, SEM, and XRD were applied and the results reveal that the superior emission property of the 75Re cathode is owing to a plenty of nanoparticles and higher free barium concentration on the cathode surface, which is attributed to the Re3W single phase in 75Re matrix.

Nb2O5 nanowires in-situ grown on carbon fiber: A high-efficiency material for the photocatalytic reduction of Cr(VI).

Niobium oxide nanowire-deposited carbon fiber (CF) samples were prepared using a hydrothermal method with amorphous Nb2O5·nH2O as precursor. The physical properties of the samples were characterized by means of numerous techniques, including X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), UV-visible spectroscopy (UV-vis), N2 adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy. The efficiency for the removal of Cr(VI) was determined. Parameters such as pH value and initial Cr(VI) concentration could influence the Cr(VI) removal efficiency or adsorption capacity of the Nb2O5/carbon fiber sample obtained after hydrothermal treatment at 160°C for 14hr. The maximal Cr(VI) adsorption capacity of the Nb2O5 nanowire/CF sample was 115mg/g. This Nb2O5/CF sample also showed excellent photocatalytic activity and stability for the reduction of Cr(VI) under UV-light irradiation: the Cr(VI) removal efficiency reached 99.9% after UV-light irradiation for 1hr and there was no significant decrease in photocatalytic performance after the use of the sample for 10 repeated cycles. Such excellent Cr(VI) adsorption capacity and photocatalytic performance was related to its high surface area, abundant surface hydroxyl groups, and good UV-light absorption ability.

The influence of yttrium dopant on the properties of anatase nanoparticles and the performance of dye-sensitized solar cells.

TiO2 mesoporous nanoparticles (NPs) doped with yttrium (Y) ions are fabricated via an environmentally friendly and facile solvothermal method to serve as a photoanode for dye sensitized solar cells (DSSCs). X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and N2 adsorption-desorption tests are used to characterize the influence of yttrium dopant on the properties of TiO2 NPs. The prepared Y-doped TiO2 NPs show the anatase phase and exhibit Ti-O-Y bonds. The photovoltaic performance is primarily associated with the morphological parameters of the NPs. At the optimum Y concentration of 3 at%, the short circuit current density increased from 13.20 to 15.74 mA cm(-2), full sun solar power conversion efficiencies increased from 6.09% up to 7.61% as compared to the blank DSSC.

Flower-, wire-, and sheet-like MnO2-deposited diatomites: Highly efficient absorbents for the removal of Cr(VI).

Flower-, wire-, and sheet-like MnO2-deposited diatomites have been prepared using a hydrothermal method with Mn(Ac)2, KMnO4 and/or MnSO4 as Mn source and diatomite as support. Physical properties of the materials were characterized by means of numerous analytical techniques, and their behaviors in the adsorption of chromium(VI) were evaluated. It is shown that the MnO2-deposited diatomite samples with different morphologies possessed high surface areas and abundant surface hydroxyl groups (especially the wire-like MnO2/diatomite sample). The wire-like MnO2/diatomite sample showed the best performance in the removal of Cr(VI), giving the maximum Cr(VI) adsorption capacity of 101 mg/g.

Swift adsorptive removal of Congo red from aqueous solution by K1.33Mn8O16 nanowires.

A swift and efficient approach to converting organic dye effluents into fresh water could be of substantial benefit. In this study, we presented facile hydrothermal synthesis of K1.33Mn8O16 nanowires in ammonium fluoride (NH4F) aqueous solution. The crystallization process of K1.33Mn8O16 nanowires was investigated. The as-obtained K1.33Mn8O16 nanowires were used for swift adsorptive removal of Congo red from aqueous solution without adjusting pH value at room temperature. Adsorption kinetic experimental data are well described by pseudo-second-order rate kinetic model, and the adsorption isotherm fits Langmuir isotherm model. The present investigation provides an efficient approach to designing and fabricating manganese-based nanomaterials for environmental remediation.

Preliminary investigation of solution diffusive behavior on V-doped TiO2 nanotubes array by electrochemical impedance spectroscopy.

V-doped TiO2 nanotubes array was successfully fabricated on a Ti-V alloy via an electrochemical anodization process. The crystal phase and surface morphology of the nanostructured film were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The solution diffusive behavior on TiO2 nanotubes was investigated by electrochemical impedance spectroscopy (EIS) analysis in an aqueous electrolyte containing 0.05 M Na2SO3. A schematic diagram of the interface solution induced into nanotube by photocatalysis on V-doped TiO2 under visible light irradiation was proposed in the study. Considerable photogenerated holes migrate to the interface of TiO2/electrolyte and react with OH-, forming hydroxyl radicals, which induce the electrolyte into the nanotube and improve the hydrophilicity. It was found that the photoelectrocatalytic reaction of TiO2 nanotubes determined the diffusion behavior of the solution; faster diffusion was observed on the V-doped TiO2 nanotubes array under visible light irradiation. The results also demonstrated that EIS is a powerful tool for characterizing the complicate diffusion behavior within the porous nanostructures.

A novel NO2 sensor based on TiO2 nanotubes array with in-situ Au decoration.

Au decorated TiO2 nanotubes array was successfully fabricated on a Ti-Au alloy via an electrochemical anodization process. The crystal phase and microstructure of the TiO2 nanotubes array were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. Au particles were well distributed among TiO2 nanotubes and acted as the catalyst. It was found that the sensor based on Ti-Au alloy anodization can be a promising sensor which was highly sensitive to low concentrations of nitrogen dioxide (NO2), and response at room temperature. The sensitivity of Au-decorated TiO2 nanotubes sensor was 36.11 to 8 ppm NO2 at room temperature. Meanwhile, the resistance signal of Au-decorated TiO2 sensor changes quickly within 80 s upon exposure to 8 ppm NO2 at 35 degrees C, the undecorated TiO2 however takes much more time (>110 s) to respond and the resistance signal remains unstable.

Preparation, characterization, and photocatalytic activity of mesoporous TiO2 thin films.

Cubic-based ordered mesoporous TiO2 thin films were prepared by an evaporation-induced self-assembly method through a carefully controlling the hydrolysis/condensation conditions. The obtained sample exhibits mesoporous structure with a narrow pore size distribution. The TiO2 thin films have thick inorganic walls composed of nanocrystalline anatase. A reasonable explanation is also proposed to elucidate the formation of thick and stable mesoporous TiO2 films. The mesoporous TiO2 exhibits good photocatalytic activity. Nearly all the methyl orange has been degraded by the mesoporous TiO2 calcined at 500 degrees C.

Facile synthesis of hierarchical hollow mesoporous Ag/WO3 spheres with high photocatalytic performance.

Hollow mesoporous tungsten trioxide spheres (HMTTS) have been synthesized by spray drying method combined with proper calcination and Ag/HMTTS are prepared on the basis of a silver mirror reaction. HMTTS are composed of nanoparticles with diameter of 20-70 nm. The accumulation of nanoparticles generates pores with the mean pore size of about 45 nm. The formation mechanism of hollow mesoporous structure is studied in this work. Ag in WO3 narrows the band gap and derceases the recombination possibility of the photogenerated electron-hole pairs, which enhance photocatalytic activity of Ag/WO3 composites. The degradation rate of methylene blue is 98.16% under UV light illumination for 75 min and 49.07% under visible light irradiation for 150 min by Ag/WO3 composites.

Influence of applied voltage on anodized TiO2 nanotube arrays and their performance on dye sensitized solar cells.

Highly ordered titanium dioxide (TiO2) nanotube films have been fabricated using anodic oxidation at different voltages (10 V to 70 V). The morphology, specific surface area, light absorbance capability and conductivity of the obtained films have been investigated. The anodized voltage was found to have a crucial influence on the morphology, light absorb capability and photo-electrochemical properties of the anodized nanotube films. The diameter of the nanotube increases linearly with the applied voltage. The nanotube film anodized at 30 V has the highest BET (Brunauer-Emmett-Teller) surface area, much more quantity of coated sensitizer N719, and the smallest resistance for dye sensitized solar cells (DSSC). Back side illuminated DSSC were assembled using these as-anodized nanotube films. Pt-FTO, which has a transmittance of about 50%, served as counter electrode. The best device based on nanotube films performed at 30 V gives a highest power conversion efficiency of 1.87%, with a photocurrent density (J(SC)) of 6.70 mA/cm2 and open circuit voltage (V(OC)) of 0.57 V.

Formation process of TiO2 nanotube arrays prepared by anodic oxidation method.

TiO2 nanotube array thin films have great potential in many fields, such as solar cell, photo catalyst, photo-induced cathodic protection for metals and bioactivity. In order to investigate the formation process of the TiO2 nanotube array thin films, the EIS spectrum and current density were measured during the anodic oxidation. The results showed that the formation process could be divided into four stages. The current density decreased sharply at the first stage, and then increased at the second stage, followed by declining and finally remained constant value. In addition, the current density increased with the anodic voltage. The EIS spectrum varied in different stage. The simulated circuit was composed three sections, the first sections indicated the resistance of the electrolyte, the second one gave the double layer structure between the electrolyte and titanium electrode, the third one was a inductive loop, which represented the anions absorbed on the surface of the TiO2 nanotube's wall. The more cations were absorbed, the higher value of the inductive loop would be. The EIS results showed that the value increased with the outer voltage, which means that more cations were absorbed under the higher anodic voltage.