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Because of the increasingly deteriorating quality of petroleum coke raw materials, abnormal furnace conditions, such as "firing and blasting", frequently arise during the calcination of petroleum coke with a high powder/coke ratio in a vertical shaft calciner. This poses an urgent technical challenge that needs to be addressed. In iron and steel metallurgy, the burden distribution system is an important way to regulate blast furnace conditions and improve the permeability of a particle packed bed. In this work, advanced burden distribution concepts were introduced into the calcination process of petroleum coke in a vertical shaft calciner. Experimental devices were established to determine the resistance characteristics of a petroleum coke particle packed bed, along with a cold physical model of a 1/8 scale vertical shaft calciner. The influence of particle size and burden distribution methods on the resistance characteristics and particle motion behavior of the petroleum coke particle packed bed was systematically studied. The research findings indicate that both particle size and burden distribution methods significantly impact the resistance characteristics of petroleum coke particle packed beds. The smaller the particle size, the poorer the permeability of the bed. The layered burden distribution, symmetrical burden distribution, and dual‐particle mixed conventional burden distribution all contribute to improving the permeability of the petroleum coke particle packed bed in the vertical shaft calciner. Furthermore, employing symmetrical burden distribution in Bed‐3, which is packed with petroleum coke particles of diameters −3.2 + 2.5 mm and −1.0 + 0.8 mm, results in the smallest unit pressure drop, at only 1.7% of that of the conventional burden distribution of unscreened raw materials. This is the most effective means of improving the permeability of the bed. During the discharging process, particle size and symmetrical burden distribution have no significant impact on the motion characteristics of petroleum coke particles in the vertical shaft calciner. In general, in the calciner area, particles primarily move in a plug flow pattern and gradually transform into funnel flow in the cooling water jacket area. These research results provide the theoretical basis for addressing the technical challenges associated with powder coke calcination in vertical shaft calciners through reasonable burden distribution methods for fine and coarse particles. [ABSTRACT FROM AUTHOR]

As the numerous industrial solid waste, coal gangue caused serious environmental pollution in China, while the it could be modified and reused as an effective adsorption material in environmental remediation. In the current study, the coal gangue was modified by environmentally friendly ball-milling chemical modification method and used for simultaneous adsorption heavy metal and ammonia in wastewater. Both the initial and modified coal gangue were characterized for structure and composition. Optimization of ball-milling conditions and adsorption parameters was carried out, followed by thermodynamic and kinetic experiments under the defined conditions. The results showed that the adsorption of Pb2+, Zn2+, and NH4+–N accorded with the quasi-second-order kinetic model, with all adsorption isotherms conforming to the Langmuir model. Thermodynamic analysis indicates that the adsorption of Pb2+, Zn2+, and NH4+–N is an exothermic process, and the adsorption reaction can occur independently. Moreover, modified coal gangue exhibited sufficient adsorption sites for the combination of Pb2+, Zn2+, and NH4+–N at low concentrations in adsorption competition experiment, with an adsorption sequence like Pb2+ > Zn2+ > NH4+–N. Our results provide that ball-milling-modified coal gangue can be used as a helpful adsorption material for heavy metal ions and ammonia removal in wastewater treatment. [ABSTRACT FROM AUTHOR]

Gallium oxide is a semiconductor material with notable optoelectronic properties and thermal stability, with potential applications in optoelectronics, aerospace, and new energy sources, among others. Nevertheless, due to its high hardness and brittleness, gallium oxide poses challenges in efficient processing. The conventional grinding of gallium oxide often results in compromised surface quality accompanied by cracks and defects. In this study, we compared the outcomes of conventional grinding (CG) and axial ultrasonic-assisted grinding (AUVAG) on the (100) and (010) planes of single-crystal β-Ga2O3 material to investigate the grinding performance of the β-Ga2O3 surface. With the inclusion of axial ultrasound, the grinding force, grinding force ratio, and surface roughness of the (100) plane decreased by 12.39%, 8.71%, and 21.14%, respectively. The (010) plane showed reductions of 25.36%, 18.65%, and 15.68%, respectively. Moreover, we explored the influence of process parameters, including wheel grinding speed, feed rate, grinding depth, and ultrasonic amplitude, on the grinding force and surface roughness through orthogonal tests. The optimal process combination was identified under the current test parameters. The findings revealed that the grinding force, grinding force ratio, and surface roughness of different crystalline planes of β-Ga2O3 were reduced to varied extents, enhancing surface quality in comparison to conventional grinding. Notably, the (010) plane of β-Ga2O3 demonstrated superior grinding performance compared to the (100) plane. The insights from this study offer valuable guidance for refining the grinding techniques and processes of single-crystal β-Ga2O3 material. [ABSTRACT FROM AUTHOR]

The adsorption–desorption behaviours of La3+, Sm3+, and Y3+ on 2‐ethylhexylphosphonic acid mono‐2‐ethyl hexyl ester (HEHEHP) extraction resin were investigated in a chloride medium. The effects of reaction time, pH, hydrochloric acid concentration, flow rate, and adsorption mechanism were studied in detail using static and dynamic experimental methods. The results show that La3+ is the first to reach adsorption equilibrium, followed by Sm3+ and Y3+; the highest adsorption capacities of La3+, Sm3+, and Y3+ are obtained at solution pH of 4 and in the order of Y3+ > Sm3+ > La3+. La3+, Sm3+, and Y3+ can be eluted by 0.3, 0.5, and 3 mol/L hydrochloric acid, respectively, indicating that La3+ elutes most easily, and Y3+ is difficult. Moreover, the flow rate has little effect on the peak of rare earth desorption. The adsorption process is chemisorption; the slope method indicates that for each mol Sm3+ or Y3+ ion adsorbed, 3 mol H+ ions are simultaneously released, but two for La3+ under the given pH conditions. It is expected to provide theoretical and technical support for preparation of ultra‐high purity rare earth by HEHEHP extraction resin. [ABSTRACT FROM AUTHOR]

Biochar has the potential to provide a multitude of benefits when used in soil remediation and increasing soil organic matter enrichment. Nevertheless, the intricated, hydrophobic pores and groups weaken its water-holding capacity in dry, sandy soils in arid lands. In order to combat this issue, starch-carbon-based material (SB), sodium alginate-carbon-based material (SAB), and chitosan-carbon-based material (CB) have been successfully synthesized through the graft-polymerization of biochar (BC). A series of soil column simulations were used to scrutinize the microstructure of the carbon-based material and explore its water absorption properties and its effects on sandy soil water infiltration, water retention, and aggregation. The results indicated that SB, SAB, and CB achieved water maximum absorption rates of 155, 188, and 172 g g−1, respectively. Considering their impact on sandy soils, SB, SAB, and CB lengthened infiltration times by 1920, 3330, and 3880 min, respectively, whilst enhancing the water retention capabilities of the soil by 18%, 25%, and 23% in comparison to solely adding BC. The utilization of these innovative materials notably encouraged the formation of sandy soil aggregates ranging from 2.0 to 0.25 mm, endowing the aggregates with enhanced structural stability. Findings from potting experiments suggested that all three carbon-based materials were conducive to the growth of soybean seeds. Thus, it is evident that the carbon-based materials have been fabricated with success, and they have great potential not only to significantly augment the water retention capacities and structural robustness of sandy soils in arid areas, but also to bolster the development of soil aggregates and crop growth. These materials possess significant application potential for enhancing the quality of sandy soils in arid and semi-arid regions. Highlights: Novel carbon-based materials were prepared using biochar and biodegradable organic matter. The novel materials exhibited excellent water absorption capacity. The novel materials greatly decreased the water infiltration capacity of sandy soil. The novel materials increased the water retention capacity and aggregate size of sandy soils. [ABSTRACT FROM AUTHOR]

Over a billion tons of high-sulfur bauxite has not been utilized effectively currently in China, because the pyrite existing in the bauxite poses a range of hazards during the Bayer process. A novel idea was proposed to remove sulfur by the silicon-containing minerals in bauxite reacting with sulfur species in sodium aluminate solution to form sulfur-bearing desilication products (SDSP) for discharge with the red mud in the Bayer process. This study investigated the reaction behavior between kaolinite and different sulfur-containing ions under the simulated Bayer process conditions, elucidating the desulfurization rate variation and formation mechanism of SDSPs. The thermodynamic calculations suggest that the reaction between kaolinite and sulfur-bearing sodium aluminate solution to form SDSPs can occur spontaneously. The experimental results demonstrated that various SDSPs can be produced through the reaction of kaolinite and sulfur-containing ions in sodium aluminate solution during the simulated Bayer process, resulting in various desulfurization efficiencies, while the desulfurization process will not result in additional alkali consumption. Increasing the kaolinite dosage, extending the reaction time, and elevating the reaction temperature all contribute positively to enhancing desulfurization efficiency. Kaolinite reacted with  S 2 O 3 2 −  in sodium aluminate solution to generate Na8Al6Si6O24S2O3·2H2O, achieving a desulfurization rate exceeding 90% under optimized conditions. Under the simulated Bayer digestion process conditions at elevated temperature, the desulfurization rates of kaolinite ranked in ascending order as  S 2 −  <  SO 3 2 −    <  SO 4 2 −  <  S 2 O 3 2 − . Kaolinite reacted with  SO 4 2 −  and  S 2 O 3 2 −  to form cancrinite type SDSPs, and a superior desulfurization rate can be achieved. This work can provide a theoretical foundation and technological support for the efficient utilization of high-sulfur bauxite by the Bayer process. [ABSTRACT FROM AUTHOR]

Yb (III) shows complex behavior of coordination dissolution and precipitation in carbonate solutions, but the properties of C O 3 2 − coordination and hydration to Yb (III) in the solution have not been explicated. In this work, the dissolution rule of Yb (III) with C O 3 2 − concentration has been studied. The radial distribution function and the coordination number of C O 3 2 − and H 2 O to Yb (III) were calculated by molecular dynamics simulation, and the complex ion form of Yb was obtained. The ultraviolet–visible spectrum and the ionic structures of Yb (III) complex ions were geometrically optimized and calculated by using density functional theory. Then, the experimental ultraviolet–visible spectra and density functional theory results were combined to verify the molecular dynamics calculations. The results indicate that Yb (III) undergoes precipitation in low-concentration carbonate solution, but, in high-concentration carbonate solution, Yb (III)'s carbonates will undergo dissolution. The main reason for the dissolution of Yb (III)'s carbonates is the coordination effect of C O 3 2 − on Yb (III); the coordination of carbonate on Yb (III) occurs with a C O 3 2 − concentration range of 0.4~2.0 mol· L − 1 . Yb (III) mainly exhibits [ Y b · 9 H 2 O ] 3 + hydrated form in the aqueous solution, while, in the carbonate solution, [ Y b · 9 H 2 O ] 3 + is converted into [ Y b (C O 3 ) 2 · 5 H 2 O ] − complex. [ Y b (C O 3 ) 2 · 5 H 2 O ] −  complex is the main ionic form in high-concentration carbonate solutions. The analysis method in this work provides guidance for understanding the coordination and hydration characteristics of oxyacid radicals to rare earth elements. [ABSTRACT FROM AUTHOR]

A two-dimensional uranyl organic framework (UOF) UO2(L)(DMA) (1) (H2L = 2-aminoisophthalic acid, DMA = N, N-dimethylacetamide) has been solvothermally synthesized and characterized thoroughly by elemental analysis, infrared spectroscopy, single-crystal X-ray diffraction, solid fluorescence, powder X-ray diffraction, thermogravimetric analysis, and UV–visible spectroscopy. Furthermore, the degradation efficiencies of UOF 1 to organic dye methylene blue (MB) and rhodamine B (RhB) are 93.2 and 86.5% under irradiation of visible light which indicates that UOF 1 has remarkable photocatalytic activity. UOF 1 also displayed a certain selectivity for mixed dyes of MB & RhB. [ABSTRACT FROM AUTHOR]

Enhancing the moisture resistance of Mn4+-doped fluoride phosphors is crucial for solid-state lighting (SSL) and liquid crystal display (LCD). Herein, the deteriorated K2AF6:Mn4+ (A = Ti, Si) phosphors were restored with Na2SO3 alkaline reductant, and optimal treatment conditions were systematically determined. The kinetic process for luminescence degradation and restoration, as well as the corresponding reparation mechanism were investigated in detail. These results showed that SO32− anion can reduce Mn4+ to Mn2+, rapidly remove the dark-brown layer of the degradation product, and restore the luminescence intensity of K2AF6:Mn4+ to more than 95%. Therefore, the restored K2TiF6: Mn4+ and K2SiF6: Mn4+ samples exhibit excellent moisture resistance, maintaining to be 66 and 76% of the initial intensity after immersing in deionized water for 300 min. Furthermore, fabricated white light-emitting device using the restored K2TiF6: Mn4+ phosphor also possess color rendering index of 94.2 and correlated color temperature of 3270 K. Our results provide a feasible strategy to significantly improve the moisture resistance of fluoride phosphors, demonstrating a great promise in phosphor-converted white-LED toward lighting and display field. [ABSTRACT FROM AUTHOR]

We present a one-step method for preparing Sm (CobalFe0.08Cu0.1Zr0.03)7.45 alloy through transition metal-induced SmF3 calciothermic reduction. The composition, crystal structure, element distribution, and chemical valence of the alloy were characterized by inductively coupled plasma, x-ray diffraction, scanning electron microscopy, x-ray energy dispersive spectroscopy, transmission electron microscopy, and x-ray photoelectron spectroscopy. The results show that the content of samarium in the alloy increases with the SmF3 amount. The composition of the alloy is similar to that of the designated alloy by adding 10 wt.% SmF3 over the theoretical addition. The reaction product is CaF2, and the ingot alloy is composed of 1:7 and 2:17 phases. The metal elements are uniformly distributed and demonstrate zero valency. The magnetic properties of the magnet show that the remanent magnetization, intrinsic coercivity, and maximum energy product are 1.15 T, 2145.30 kA/m, and 205.34 kJ/m3, respectively. [ABSTRACT FROM AUTHOR]

The adsorption–desorption behavior of La3+, Eu3+, and Y3+ by Mg(OH)2-pretreated TP207 resin in sulfate solution has been investigated. The effects of the reaction duration, pH value, flow rate, and adsorption mechanism were studied in detail. The results show that the highest adsorption capacity is obtained at solution pH of 4.0. The adsorption affinity of the resin for the different rare-earth ions lies in the order La3+ > Eu3+ > Y3+, while the static equilibrium adsorption capacity is 0.73 mmol g−1, 0.51 mmol g−1, and 0.35 mmol g−1, respectively. The optimum desorption conditions are 1 mol L−1 hydrochloric acid at a flow rate of 4 mL min−1. The desorption liquid enrichment peaks follow the order La3+ > Eu3+ > Y3+, with corresponding enrichment factors of 24, 23, and 20. The adsorption process of TP207 resin is chemisorption, and the coordination mode between Y3+ and resin functional groups is dominated by three donor atoms, but two for La3+ and Eu3+. [ABSTRACT FROM AUTHOR]

Two new isostructural lanthanide(III) coordination polymers based on an unreported zwitterionic ligand, namely, [Ln(ox)(L)]n (ox = oxalate, HL = N,N' -dipropionic acid imidazolium, Ln = Eu or La), are synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. The fluorescence properties of the europium coordination polymer are investigated. In addition, the europium-based coordination polymer is utilized for specific sensing of UO22+ ions, showing high selectivity, a fast response time (8 min) and high sensitivity with noticeable quenching (K sv = 6.19 × 104 M−1) and limit of detection of 1.95 µM. [ABSTRACT FROM AUTHOR]

Fluoride molten-salt electrolytic slag is an important secondary resource for recovery of rare earth elements. In this study, the recovery of rare earths from this source was systemically investigated using borax roasting followed by hydrochloric acid leaching. Increasing the roasting temperature, reaction time and borax dosage promoted the recovery of rare earth elements. The roasting process kinetics was controlled by interfacial chemical reaction, with an activation energy of 159.02 kJ mol−1. The leaching experiments demonstrated that increasing the leaching temperature, time, hydrochloric acid concentration and liquid/solid ratio improved the rare earth recovery. The optimum conditions were identified as roasting the slag at 700°C for 60 min with a borax mass dosage of 38 wt.% and subsequently leaching the resulting rare earth-containing residues in 4 mol L−1 HCl at 60°C at a liquid/solid ratio of 5:1 for 40 min. These conditions gave a rare earth recovery exceeding 97%. This work proposes a novel technical route for efficiently and economically recovering rare earths from this source. [ABSTRACT FROM AUTHOR]

Purpose: Dose calculation is one of the most computationally intensive, yet essential tasks in the treatment planning process. With the recent interest in automatic beam orientation and arc trajectory optimization techniques, there is a great need for more efficient model‐based dose calculation algorithms that can accommodate hundreds to thousands of beam candidates at once. Foundational work has shown the translation of dose calculation algorithms to graphical processing units (GPUs), lending to remarkable gains in processing efficiency. But these methods provide parallelization of dose for only a single beamlet, serializing the calculation of multiple beamlets and under‐utilizing the potential of modern GPUs. In this paper, the authors propose a framework enabling parallel computation of many beamlet doses using a novel beamlet context transformation and further embed this approach in a scalable network of multi‐GPU computational nodes. Methods: The proposed context‐based transformation separates beamlet‐local density and TERMA into distinct beamlet contexts that independently provide sufficient data for beamlet dose calculation. Beamlet contexts are arranged in a composite context array with dosimetric isolation, and the context array is subjected to a GPU collapsed‐cone convolution superposition procedure, producing the set of beamlet‐specific dose distributions in a single pass. Dose from each context is converted to a sparse representation for efficient storage and retrieval during treatment plan optimization. The context radius is a new parameter permitting flexibility between the speed and fidelity of the dose calculation process. A distributed manager‐worker architecture is constructed around the context‐based GPU dose calculation approach supporting an arbitrary number of worker nodes and resident GPUs. Phantom experiments were executed to verify the accuracy of the context‐based approach compared to Monte Carlo and a reference CPU‐CCCS implementation for single beamlets and broad beams composed by addition of beamlets. Dose for representative 4π beam sets was calculated in lung and prostate cases to compare its efficiency with that of an existing beamlet‐sequential GPU‐CCCS implementation. Code profiling was also performed to evaluate the scalability of the framework across many networked GPUs. Results: The dosimetric accuracy of the context‐based method displays <1.35% and 2.35% average error from the existing serialized CPU‐CCCS algorithm and Monte Carlo simulation for beamlet‐specific PDDs in water and slab phantoms, respectively. The context‐based method demonstrates substantial speedup of up to two orders of magnitude over the beamlet‐sequential GPU‐CCCS method in the tested configurations. The context‐based framework demonstrates near linear scaling in the number of distributed compute nodes and GPUs employed, indicating that it is flexible enough to meet the performance requirements of most users by simply increasing the hardware utilization. Conclusions: The context‐based approach demonstrates a new expectation of performance for beamlet‐based dose calculation methods. This approach has been successful in accelerating the dose calculation process for very large‐scale treatment planning problems ‐ such as automatic 4π IMRT beam orientation and VMAT arc trajectory selection, with hundreds of thousands of beamlets ‐ in clinically feasible timeframes. The flexibility of this framework makes it as a strong candidate for use in a variety of other very large‐scale treatment planning tasks and clinical workflows. [ABSTRACT FROM AUTHOR]

The addition of a red-emitting phosphor to YAG:Ce3+-based white light-emitting diodes (WLEDs) greatly facilitates their applications in the field of high-color-rendering-index warm solid-state lighting. It is highly desirable to develop a red phosphor with satisfactory spectral features and low synthesis cost. In this study, a novel non-rare-earth and nonequivalent doping type of Cs2NbOF5:Mn4+ oxyfluoride red-emitting phosphor with high luminous efficiency was obtained via a facile room-temperature co-precipitation method, and its morphology and luminescent properties were investigated in detail. The Cs2NbOF5:Mn4+ phosphor with micro-rod-like morphology exhibited broad band absorption at blue light region (∼474 nm) and narrow bandwidth emissions at red region (∼633 nm). The color purity of the Cs2NbOF5:Mn4+ phosphor was calculated to be about 99%, and the internal quantum yield (QY) under 474 nm excitation was 63.4%. The concentration quenching of Mn4+ in Cs2NbOF5 matrix was mainly due to dipole–dipole interactions, and the activation energy of temperature quenching was calculated to be ∼0.2610 eV. The demonstration of a blue InGaN LED chip in combination with a blend of newly developed Cs2NbOF5:Mn4+ red phosphor and YAG:Ce3+ yellow phosphor greatly decreased the correlated color temperature (CCT) from 6255 to 3517 K while significantly improving the color rendering index (CRI) from 72.5 to 87.5. It deserves to be mentioned that the brand-new matrix to phosphor in the present study can be extended to various niobium/tantalum oxyfluoride series, which is very helpful for developing and designing new red phosphors. [ABSTRACT FROM AUTHOR]

Phosphoinositide-specific phospholipase C (PI-PLC) plays a central role in the phosphatidylinositol specific signal transduction pathway. Plant PI-PLCs have been demonstrated to be involved in various stimuli and physiological processes. Five Arabidopsis thaliana PI-PLC genes were overexpressed transiently in tobacco leaves, and one of them, AtPLC5, was stably expressed in transgenic Arabidopsis; a dexamethasone-inducible promoter was used. Expression of AtPLC5 in transiently transformed tobacco resulted in leaf senescence at 72 h after induction, while other AtPLC did not cause any visible changes. Stable overexpression of AtPLC5 in transgenic Arabidopsis resulted in clearly induced visible yellowing at 8 days after induction, meanwhile chlorophyll content was decreased, PI-PLC activity and electric conductivity were increased. qPCR results demonstrated that increased transcription of senescence-associated genes ( SAG12, SAG13, SAG15, SAG18 and SAG29) were up regulated after AtPLC5 induction. When AtPLC5 fused with green fluorescent protein was transiently expressed in protoplasts prepared from Arabidopsis mesophyll cells, green fluorescence was clearly observed in the plasma membrane (PM). Moreover, western blot analysis indicated that AtPLC5 was found to be enriched in the PM fraction of transgenic Arabidopsis stably expressing AtPLC5. These results suggest that AtPLC5 is predominantly localized in the PM and may be a regulator of leaf senescence. [ABSTRACT FROM AUTHOR]

Purpose: Using the graphical processing units (GPU) hardware technology, an extremely fast Monte Carlo (MC) code ARCHERRT is developed for radiation dose calculations in radiation therapy. This paper describes the detailed software development and testing for three clinical TomoTherapy ® cases: the prostate, lung, and head & neck. Methods: To obtain clinically relevant dose distributions, phase space files (PSFs) created from optimized radiation therapy treatment plan fluence maps were used as the input to ARCHERRT. Patientspecific phantoms were constructed from patient CT images. Batch simulations were employed to facilitate the time-consuming task of loading large PSFs, and to improve the estimation of statistical uncertainty. Furthermore, two different Woodcock tracking algorithms were implemented and their relative performance was compared. The dose curves of an Elekta accelerator PSF incident on a homogeneous water phantom were benchmarked against DOSXYZnrc. For each of the treatment cases, dose volume histograms and isodose maps were produced from ARCHERRT and the general-purpose code, GEANT4. The gamma index analysis was performed to evaluate the similarity of voxel doses obtained from these two codes. The hardware accelerators used in this study are one NVIDIA K20 GPU, one NVIDIA K40 GPU, and six NVIDIA M2090 GPUs. In addition, to make a fairer comparison of the CPU and GPU performance, a multithreaded CPU code was developed using OpenMP and tested on an Intel E5-2620 CPU. Results: For the water phantom, the depth dose curve and dose profiles from ARCHERRT agree well with DOSXYZnrc. For clinical cases, results from ARCHERRT are compared with those from GEANT4 and good agreement is observed. Gamma index test is performed for voxels whose dose is greater than 10% of maximum dose. For 2%/2mm criteria, the passing rates for the prostate, lung case, and head & neck cases are 99.7%, 98.5%, and 97.2%, respectively. Due to specific architecture of GPU, modified Woodcock tracking algorithm performed inferior to the original one. ARCHERRT achieves a fast speed for PSF-based dose calculations. With a single M2090 card, the simulations cost about 60, 50, 80 s for three cases, respectively, with the 1% statistical error in the PTV. Using the latest K40 card, the simulations are 1.7-1.8 times faster. More impressively, six M2090 cards could finish the simulations in 8.9-13.4 s. For comparison, the same simulations on Intel E5-2620 (12 hyperthreading) cost about 500-800 s. Conclusions: ARCHERRT was developed successfully to perform fast and accurate MC dose calculation for radiotherapy using PSFs and patient CT phantoms. [ABSTRACT FROM AUTHOR]

Cotton ( Gossypium spp.) is an important fiber and oil crop. High soil salinity affects cotton growth and production severely. To identify genes in response to salt stress and clarify salt tolerance mechanism in cotton, suppression subtractive hybridization (SSH) libraries were constructed from cotton roots under salt stress. A total of 1,131 expressed sequence tags (ESTs) from both forward and reverse libraries were assembled into 468 uniESTs and grouped into 11 functional categories according to Gene Ontology prediction. The results showed that many physiological processes of cotton were influenced by salt stress. Some signaling elements and transcription factors, which might play important roles in salt stress response, were carefully discussed. The expression patterns of 21 selected genes under salt stress were validated by parallel method semi-quantitative reverse transcriptase-polymerase chain reaction (semi-quantitative RT-PCR), which were consistent with SSH results. An interaction network of salt-responsive genes was constructed and three molecular regulatory pathways of cotton were deduced. Our findings might result in further understanding of salt stress response in cotton and contribute to genetically modified cotton with enhanced salt tolerance. [ABSTRACT FROM AUTHOR]

Rare earths dissolved in carbonate solutions exhibit a metastable state. During the period of metastability, rare earths dissolve stably without precipitation. In this paper, neodymium was chosen as a representative rare earth element. The effects of additional NaCl and CO2 on the metastable state were investigated. The metastable state can be controlled by adding NaCl to the Na2CO3 solution. Molecular dynamics studies indicated that the Cl− provided by the additional NaCl partially occupied the coordination layer of Nd3+, causing the delayed formation of neodymium carbonate precipitation. In addition, the additional NaCl decreased the concentration of free carbonate in the solution, thereby reducing the behavior of free contact between carbonate and Nd, as well as resulting in the delay of Nd precipitate formation. Consequently, the period of the metastable state was prolonged in the case of introduction of NaCl. However, changing the solution environment by introducing CO2 can destroy the metastable state rapidly. Introduction of CO2 gas significantly decreased the CO32− content in the solution and increased its activity, resulting in an increase of the free CO32− concentration of the solution in the opposite direction. As a result, the precipitation process was accelerated and the metastable state was destroyed. It was possible to obtain a large amount of rare earth carbonate precipitation in a short term by introducing CO2 into the solution with dissolved rare earths in the metastable state to achieve rapid separation of rare earths without introducing other precipitants during the process. [ABSTRACT FROM AUTHOR]