Rtr1 is required for Rpb1-Rpb2 assembly of RNAPII and prevents their cytoplasmic clump formation.

RNA polymerase II (RNAPII) is an essential machinery for catalyzing mRNA synthesis and controlling cell fate in eukaryotes. Although the structure and function of RNAPII have been relatively defined, the molecular mechanism of its assembly process is not clear. The identification and functional analysis of assembly factors will provide new understanding to transcription regulation. In this study, we identify that RTR1, a known transcription regulator, is a new multicopy genetic suppressor of mutants of assembly factors Gpn3, Gpn2, and Rba50. We demonstrate that Rtr1 is directly required to assemble the two largest subunits of RNAPII by coordinating with Gpn3 and Npa3. Deletion of RTR1 leads to cytoplasmic clumping of RNAPII subunit and multiple copies of RTR1 can inhibit the formation of cytoplasmic clump of RNAPII subunit in gpn3-9 mutant, indicating a new layer function of Rtr1 in checking proper assembly of RNAPII. In addition, we find that disrupted activity of Rtr1 phosphatase does not trigger the formation of cytoplasmic clump of RNAPII subunit in a catalytically inactive mutant of RTR1. Based on these results, we conclude that Rtr1 cooperates with Gpn3 and Npa3 to assemble RNAPII core.

Spatial dynamics of a vegetation model with uptake-diffusion feedback in an arid environment.

Vegetation patterns with a variety of structures is amazing phenomena in arid or semi-arid areas, which can identify the evolution law of vegetation and are typical signals of ecosystem functions. Many achievements have been made in this respect, yet the mechanisms of uptake-diffusion feedback on the pattern structures of vegetation is not fully understood. To well reveal the influences of parameters perturbation on the pattern formation of vegetation, we give a comprehensive analysis on a vegetation-water model in the forms of reaction-diffusion equation which is posed by Zelnik et al. (Proc Natl Acad Sci 112:12,327-12,331, 2015). We obtain the exact parameters range for stationary patterns and show the dynamical behaviors near the bifurcation point based on nonlinear analysis. It is found that the model has the properties of spot, labyrinth and gap patterns. Moreover, water diffusion rate prohibits the growth of vegetation while shading parameter promotes the increase of vegetation biomass. Our results show that gradual transitions from uniform state to gap pattern can occur for suitable value of parameters which may induce the emergence of desertification.

Synthesis of Mesoporous Co3O4/NiCo2O4 Nanorods and Their Electrochemical Study.

Mesoporous Co3O4/NiCo2O4 nanorods were obtained by a hydrothermal reaction with the assistance of Ni foam and subsequent annealing treatment. The characterization of this composition by X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, energy dispersive spectra and Brunauer-Emmett-Teller analysis revealed that the nanorods consisted of Co3O4 and NiCo2O4 phase, exhibiting high porosity and rich crystal defects. The electrochemical data showed a specific capacitance of 1173 mF cm-2 and 606 mF cm-2 at 2 mV s-1 and 1 mA cm-2, respectively. Its cycling performance was 83.9% at 3 mA cm-2 after 4000 cycles. Furthermore, the asymmetric supercapacitor Co3O4/NiCo2O4//AC delivered an energy density of 11.7 W h kg-1 and power density of 760 W kg-1.

Hydroxyapatite (HA) Modified Nanocoating Enhancement on AZ31 Mg Alloy by Combined Surface Mechanical Attrition Treatment and Electrochemical Deposition Approach.

Hydroxyapatite (HA) nanocoating was electrodeposited on the surface mechanical attrition treated (SMATed) AZ31 magnesium alloy. Phases, morphologies and the adhesion of coating were characterized by X-ray diffraction, scanning electron microscopy (SEM) and 3D optical profiler. The corrosion resistance of the HA coating was tested by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the HA coating on SMATed sample had a better crystallization than that on original one. The thickness of HA coating increased from 25 to 40 µm. The bonding strength between HA coating and SMATed substrate was higher than that between the coating and untreated counterpart. Potentiodynamic polarization and EIS demonstrated that the corrosion current density of HA coating on SMATed substrate decreased by 30.84% than that on original. The corrosion potential shifted 80.3 mV to the positive direction. The corrosion resistance of coatings on SMATed sample was significantly enhanced. The immersion experiments showed that the HA coatings on SMATed sample exhibited a better biological activity.

A simple synthesis of hollow Mn2O3 core-shell microspheres and their application in lithium ion batteries.

Hollow Mn2O3 core-shell microspheres were successfully fabricated via a mixed method including a solution method and a subsequent thermal decomposition. Transmission electron microscopy showed that the average size of Mn2O3 cores was about 0.8 µm and their shell thickness was 120 nm. These hollow Mn2O3 core-shell microspheres as anode materials exhibited a high specific capacity of up to 620 mA h g(-1) with a good cycling performance (500 cycles), indicating that the hollow Mn2O3 core-shell microsphere material was a promising anode candidate for a high-capacity, low-cost, and environment-friendly lithium ion battery. The formation mechanism was studied in detail.

Electrochemical Corrosion Behaviour of X70 Steel under the Action of Capillary Water in Saline Soils.

In this paper, the electrochemical corrosion behavior of X70 steel in saline soil under capillary water was simulated by a Geo-experts one-dimensional soil column instrument. A volumetric water content sensor and conductivity test were used to study the migration mechanism of water and salt (sodium chloride) under the capillary water. The electrochemical corrosion behavior of the X70 steel in the corrosion system was analyzed by electrochemical testing as well as the macroscopic and microscopic corrosion morphology of the steel. The test results showed that the corrosion behavior of X70 steel was significantly influenced by the rise of capillary water. In particular, the wetting front during the capillary water rise meant that the X70 steel was located at the three-phase solid/liquid/gas interface at a certain location, which worsened its corrosion behavior. In addition, after the capillary water was stabilized, the salts were transported with the capillary water to the top of the soil column. This resulted in the highest salt content in the soil environment and the most severe corrosion of the X70 steel at this location.

Npa3-Gpn3 cooperate to assemble RNA polymerase II and prevent clump of its subunits in the cytoplasm.

RNA polymerase II (RNAPII) is an essential machinery in eukaryotes that catalyzes mRNA synthesis and controls cell fate. Although the structure and function of RNAPII are relatively well defined, the molecular mechanism of its assembly process is poorly understood. Three members of GPN-loop GTPase family Npa3/Gpn1, Gpn2, and Gpn3 participate in the biogenesis of RNAPII with non-redundant roles. In this study, we demonstrate that Gpn3 and Npa3 directly participate in the assembly of the two largest subunits during biogenesis of RNAPII. When Gpn3 is defective, assembly of RNAPII is disrupted, leading to cytoplasmic foci of RNAPII subunits. Long-term assembly factor defects will lead to the accumulation of different kind of newly synthesized RNAPII subunits in the cytoplasm to form foci, and this can be prevented by recovery of the defective assembly factor. Cytoplasmic foci of RNAPII subunits in mutants of these assembly factors reveals a new cellular rescue response named the 'RNAPII assembly stress response'.

Ultrathin Solid Polymer Electrolyte Design for High-Performance Li Metal Batteries: A Perspective of Synthetic Chemistry.

Li metal batteries (LMBs) have attracted widespread attention in recent years because of their high energy densities. But traditional LMBs using liquid electrolyte have potential safety hazards, such as: leakage and flammability. Replacing liquid electrolyte with solid polymer electrolyte (SPE) can not only significantly improve the safety, but also improve the energy density of LMBs. However, till now, there is only limited success in improving the various physical and chemical properties of SPE, especially in thickness, posing great obstacles to further promoting its fundamental and applied studies. In this review, the authors mainly focus on evaluating the merits of ultrathin SPE and summarizing its existing challenges as well as fundamental requirements for designing and manufacturing advanced ultrathin SPE in the future. Meanwhile, the authors outline existing cases related to this field as much as possible and summarize them from the perspective of synthetic chemistry, hoping to provide a comprehensive understanding and serve as a strategic guidance for designing and fabricating high-performance ultrathin SPE. Challenges and opportunities regarding this burgeoning field are also critically evaluated at the end of this review.

A New Explanation for the Effect of Dynamic Strain Aging on Negative Strain Rate Sensitivity in Fe-30Mn-9Al-1C Steel.

In this study, the evolution of the mechanical properties of Fe-30Mn-9Al-1C steel has been determined in tensile tests at strain rates of 10-4 to 102 s-1. The results show that the strain rate sensitivity becomes a negative value when the strain rate exceeds 100 s-1 and this abnormal evolution is attributed to the occurrence of dynamic strain aging. Due to the presence of intergranular κ-carbides, the fracture modes of steel include ductile fracture and intergranular fracture. The values of dislocation arrangement parameter M were obtained using a modified Williamson-Hall plot. It has been found that once the strain rate sensitivity becomes negative, the interaction of dislocations in the steel is weakened and the free movement of dislocation is enhanced. Adiabatic heating promotes the dynamic recovery of steel at a high strain rate.

Dark Septate Endophytes Improve the Growth and the Tolerance of Medicago sativa and Ammopiptanthus mongolicus Under Cadmium Stress.

Although the ecological function of dark septate endophytes (DSEs) is well studied, little is known about the responses of the host plant to DSEs obtained from other plants, especially under conditions of heavy metal stress. This study aimed to investigate how DSEs from a heavy-metal habitat affect non-host plants in cadmium (Cd) stress soils, which then provides a basis for the application of DSEs in the cultivation of different plant and soil remediation strategies for polluted ecosystems. We isolated and identified two species of DSE (Acrocalymma vagum and Scytalidium lignicola) inhabiting the roots of Ilex chinensis (host plant) which are grown in metal-polluted habitats. Then, the Cd stress tolerance of the DSEs was tested using a pure culture of which the Cd concentration has been adjusted. Subsequently, we examined the performance of non-host plants (Medicago sativa and Ammopiptanthus mongolicus) which were inoculated with DSEs under Cd stress in a growth chamber. The results indicated that the two DSEs could grow under Cd stress in vitro, even when not exhibiting high levels of tolerance to Cd. The superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), soluble protein, and melanin of the DSE fungi reached maximal levels at concentrations of 30-60 mg Cd/L, indicating the important preventive strategies adopted by the DSE fungi in environments contaminated by Cd. Despite a decreased biomass of DSE hyphae with enhanced Cd concentrations, the accumulation of Cd in the DSE hyphae tended to show an increasing trend. Both DSEs were effective colonizers of the non-host plants. A. vagum and S. lignicola inoculation significantly promoted the biomass and the root architecture of the two non-host plants under Cd stress. A. vagum inoculation increased the total nitrogen (TN) of A. mongolicus, whereas inoculation with S. lignicola significantly increased the organic carbon (OC) of M. sativa. In particular, the DSE inoculation significantly improved the accumulation of Cd in plant tissues under Cd stress, demonstrating a potential application in the bio-remediation of heavy-metal-pollution areas. Our findings suggest that the DSE inoculation improved the root growth and nutrient absorption of non-host plants, altered the soil Cd concentration, and facilitated plant growth and survival under Cd stress. These results contribute to a better understanding of DSE-plant interactions in habitats contaminated by heavy metals.

Investigation on Wear Behavior of Cryogenically Treated Ti-6Al-4V Titanium Alloy under Dry and Wet Conditions.

Titanium alloys are widely used in many fields because of their excellent comprehensive properties. However, its poor friction and wear properties limit its many potential applications. In general, the surface roughness of important parts manufactured by titanium alloy should meet certain requirements. As a low-cost and high-efficiency processing method, barrel finishing has been used for the surface finishing of titanium alloys. The main material removal mechanism of barrel finishing is micro-cutting/grinding, which is similar to the material wear mechanism under some conditions. In addition, titanium alloys are subjected to a low force in common surface finishing processes. Cryogenic treatment is a method that can improve the comprehensive properties of titanium alloys. Therefore, the friction and wear behavior of cryogenically treated Ti-6Al-4V titanium alloy (CT Ti alloy) and non-cryogenically treated Ti-6Al-4V titanium alloy (NT Ti alloy) at a low load and scratch speed was studied comparatively in this paper. The results show that the CT Ti alloy exhibits a lower friction coefficient and wear rate under both dry and wet wear conditions. Under wet conditions, the stabilized friction coefficient is lower than that under dry conditions. The stabilized friction coefficient of CT Ti alloy is 0.18 after reaching a stable wear stage under wet conditions. Under dry wear conditions, the NT Ti alloy mainly showed typical abrasive wear, heavy adhesion wear and oxidation wear characters. The wear mechanisms of CT Ti alloy are mainly abrasive wear, slight adhesion wear and oxidation wear. Under wet wear conditions, the wear mechanism of NT Ti alloy is abrasive wear and slight adhesion wear. After cryogenic treatment, the mechanism for CT Ti alloy is slight abrasive wear.

Unusual formation of NiCo2O4@MnO2/nickel foam/MnO2 sandwich as advanced electrodes for hybrid supercapacitors.

A facile three-step method is designed for large-scale preparation of a NiCo2O4@MnO2/nickel foam/MnO2 sandwich architecture with robust adhesion as an advanced electrode for high-performance supercapacitors. The synthesis contains the hydrothermal reaction of a cobalt-nickel hydroxide precursor on a nickel foam (NF) support and subsequent thermal conversion into spinel mesoporous NiCo2O4 nanowire arrays, followed by a hydrothermal oxidation reaction to synthesize NiCo2O4@MnO2/nickel foam/MnO2 sandwiches. Moreover, the tactics reported in this study enable easy control of the growth of NiCo2O4 on one side of the NF and MnO2 nanosheets on both sides of the NF to obtain novel NiCo2O4@MnO2/nickel foam/MnO2 sandwiches. Because of the unusual structural and compositional features, the obtained NiCo2O4@MnO2/nickel foam/MnO2 sandwiches manifest excellent performance with high specific capacitance (1.70 C cm-2 at 2 mA cm-2), exceptional rate capability (78.5% retention at 20 mA cm-2) and ultralong cycling stability (91% retention over 30 000 cycles at 20 mA cm-2) as a battery-type electrode material for supercapacitors. When further assembled into an aqueous hybrid supercapacitor, it can deliver an energy density of 53.5 W h kg-1 at a power density of 80 W kg-1 and 20.7 W h kg-1 at 8 kW kg-1. This novel sandwich electrode provides a new idea for improving the electrochemical performance of hybrid supercapacitors.

Dark septate endophytes isolated from a xerophyte plant promote the growth of Ammopiptanthus mongolicus under drought condition.

Dark septate endophytes (DSE) may facilitate plant growth and stress tolerance in stressful ecosystems. However, little is known about the response of plants to non-host DSE fungi isolated from other plants, especially under drought condition. This study aimed to seek and apply non-host DSE to evaluate their growth promoting effects in a desert species, Ammopiptanthus mongolicus, under drought condition. Nine DSE strains isolated from a super-xerophytic shrub, Gymnocarpos przewalskii, were identified and used as the non-host DSE. And DSE colonization rate (30-35%) and species composition in the roots of G. przewalskii were first reported. The inoculation results showed that all DSE strains were effective colonizers and formed a strain-dependent symbiosis with A. mongolicus. Specifically, one Darksidea strain, Knufia sp., and Leptosphaeria sp. increased the total biomass of A. mongolicus compared to non-inoculated plants. Two Paraconiothyrium strains, Phialophora sp., and Embellisia chlamydospora exhibited significantly positive effects on plant branch number, potassium and calcium content. Two Paraconiothyrium and Darksidea strains particularly decreased plant biomass or element content. As A. mongolicus plays important roles in fixing moving sand and delay desertification, the ability of certain DSE strains to promote desert plant growth indicates their potential use for vegetation recovery in arid environments.

Controllable thermal and pH responsive behavior of PEG based hydrogels and applications for dye adsorption and release.

A series of controllable thermal and pH dual-responsive copolymeric hydrogels (PMA) were prepared by a one-pot reaction with poly(ethylene glycol) methyl ether acrylate (PEGA), 2-methoxyethyl acrylate (MEA) and acroleic acid (AA). The hydrogels exhibited good mechanical properties and a sensitive response to pH and temperature. Besides, the Lower Critical Solution Temperature (LCST) of the hydrogels can be adjusted from 37 °C to 58 °C by changing the content of AA. The hydrogels also showed excellent selective adsorption properties. The maximum adsorption quantity of organic cationic dye brilliant green and methylene blue were 0.49 mg mg-1 and 0.42 mg mg-1 respectively, much better than previous reports. Furthermore, using the thermal and pH responsibility, the PMA hydrogels can release the adsorbed molecules with control. Nearly 95% of carriers could be released at pH 4.01 and 65 °C over 8 h. The regeneration ability makes the materials easy to reuse many times. Due to these properties, these dual-responsive hydrogels have great potential applications in various fields for adsorption, drug delivery, release and tissue engineering.

Corrosion Behavior of the As-Cast and As-Solid Solution Mg-Al-Ge Alloy.

The corrosion behavior of Mg-3Al-xGe (x = 1, 3, 5) alloy in as-cast and as-solid was investigated by virtue of microstructure, corrosion morphology observation, and electrochemical measurement. Among the as-cast alloys, the corrosion rate of Mg-3Al-1Ge with a discontinuous bar-morphology was the highest, which was 101.7 mm·a-1; the corrosion rate of Mg-3Al-3Ge with a continuous network distribution was the lowest, which was 23.1 mm·a-1; and the corrosion rate of Mg-3Al-5Ge of Ge-enriched phase with sporadic distribution was in-between, which was 63.9 mm·a-1. It is suggested that the morphology of the Mg2Ge phase changes with a change in Ge content, which affects the corrosion performance of the alloy. After solid solution treatment, the corrosion rate of the corresponding solid solution alloy increased-Mg-3Al-1Ge to 140.5 mm·a-1, Mg-3Al-3Ge to 52.9 mm·a-1, and Mg-3Al-5Ge to 87.3 mm·a-1, respectively. After investigation of the microstructure, it can be suggested that solid solution treatment dissolves the Mg17Al12 phase, which changes the phase composition of the alloy and also affects its microstructure, thus affecting its corrosion performance.

Highly Stable Gully-Network Co3O4 Nanowire Arrays as Battery-Type Electrode for Outstanding Supercapacitor Performance.

3D transition metal oxides, especially constructed from the interconnected nanowires directly grown on conductive current collectors, are considered to be the most promising electrode material candidates for advanced supercapacitors because 3D network could simultaneously enhance the mechanical and electrochemical performance. The work about design, fabrication, and characterization of 3D gully-network Co3O4 nanowire arrays directly grown on Ni foam using a facile hydrothermal procedure followed by calcination treatment will be introduced. When evaluated as a binder-free battery-type electrode for supercapacitor, a high specific capacity of 582.8 C g-1 at a current density of 1 A g-1, a desirable rate capability with capacity retention about 84.8% at 20 A g-1, and an outstanding cycle performance of 93.1% capacity retention after 25,000 cycles can be achieved. More remarkably, an energy density of 33.8 W h kg-1 at a power density of 224 W kg-1 and wonderful cycling stability with 74% capacity retention after 10,000 cycles can be delivered based on the hybrid-supercapacitor with the as-prepared Co3O4 nanowire arrays as a positive electrode and active carbon as negative electrode. All the unexceptionable supercapacitive behaviors illustrates that our unique 3D gully-network structure Co3O4 nanowire arrays hold a great promise for constructing high-performance energy storage devices.

Facile Synthesis of Hierarchical Mesoporous Honeycomb-like NiO for Aqueous Asymmetric Supercapacitors.

Three-dimensional (3D) hierarchical nanostructures have been demonstrated as one of the most ideal electrode materials in energy storage systems due to the synergistic combination of the advantages of both nanostructures and microstructures. In this study, the honeycomb-like mesoporous NiO microspheres as promising cathode materials for supercapacitors have been achieved using a hydrothermal reaction, followed by an annealing process. The electrochemical tests demonstrate the highest specific capacitance of 1250 F g(-1) at 1 A g(-1). Even at 5 A g(-1), a specific capacitance of 945 F g(-1) with 88.4% retention after 3500 cycles was obtained. In addition, the 3D porous graphene (reduced graphene oxide, rGO) has been prepared as an anode material for supercapacitors, which displays a good capacitance performance of 302 F g(-1) at 1 A g(-1). An asymmetric supercapacitor has been successfully fabricated based on the honeycomb-like NiO and rGO. The asymmetric supercapacitor achieves a remarkable performance with a specific capacitance of 74.4 F g(-1), an energy density of 23.25 Wh kg(-1), and a power density of 9.3 kW kg(-1), which is able to light up a light-emitting diode.

Structural characteristics of nanocrystalline copper after carbon ion implantation.

A gradient structure was produced in a pure copper plate by means of surface mechanical attrition treatment (SMAT). The microstructure of the surface layer was reduced to nanoscale and the grain size increased gradually along the depth of the treated sample. In situ transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) observation was performed on the nanocrystalline copper after implantation of carbon. Carbon atoms first precipitated along the edges of the copper substrate or at the surface, then formed amorphous carbon layers. Subsequently, onion-like fullerenes were formed under electron-beam irradiation. The effects of ion implantation, electron beam irradiation, nanostructure of the substrate and interaction of C and Cu atoms on the formation of the onion-like fullerenes are discussed.