Adsorption of Fluoride from Aqueous Solution Using Low-Cost Bentonite/Chitosan Beads

A new adsorbent namely bentonite/chitosan beads has been synthesized and studied for its defluoridation efficiency. Bentonite was activated and the beads were prepared using the inverse suspension polymerization method. The bentonite/chitosan beads (bentonite dosage of 3.0 g) showed an adsorption capacity of 0.895 mg/g whereas chitosan beads had only 0.359 mg/g. The optimal pH value was observed at pH 5 where the adsorbent reached the maximum defluoridation capacity of 1.164 mg/g. The effect of temperature, contact time and initial fluoride concentration on the adsorption capacity of the adsorbent has also been investigated. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and Fourier-transform infrared spectrometry (FTIR) were used to characterize the adsorbent. The adsorption of fluoride onto the adsorbent followed Freundlich isotherm model and pseudo-second order kinetic model. The fluoride loaded adsorbent could be regenerated using sodium hydroxide.

Study on the Resistance Levels of Different Echinochloa crusgalli Populations to Penoxsulam and Bispyribac-sodium

[Objectives]This study was conducted to screen the resistance of Echinochloa crusgalli in some paddy fields in Changde City,Yiyang City and Yueyang City in Hunan Province to penoxsulam and bispyribac-sodium.[Methods]The resistance to penoxsulam and bispyribac-sodium was screened in 11 E.crusgalli populations collected from rice production areas in Changde,Yiyang and Yueyang Cities,Hunan Province,and the resistance level of population HU-2 to penoxsulam was determined.[Results]HU-1 to HU-6 and HU-8 A,a total of seven populations showed high levels of resistance to penoxsulam and bispyribac-sodium.The resistance level of population HU-2 to penoxsulam was extremely high;population HU-7 showed low-level resistance to both drugs;HU-11 population showed low-level resistance to penoxsulam and was susceptible to bispyribac-sodium;and populations HU-8 and HU-9 were susceptible to penoxsulam and bispyribac-sodium.[Conclusions]This study provides a technical basis for the rational use of penoxsulam and bispyribac-sodium and the selection of control chemicals for E.crusgalli in paddy fields.

Monitoring and engineering interface coupling between monolayer WS_(2)and substrate through controllably introducing interfacial strain

The interface properties in two-dimensional(2D)layered materials and their van der Waals(vdW)homo-/heterostructures are of importance in both uncovering novel physical phenomena and optimizing device performance.Despite considerable research interest and enthusiasm direct toward the interlayer coupling in 2D homo-and heterostructures,there is limited research on the coupling at the 2D layered material-substrate interface.This limitation is due to the challenges in achieving direct detection.Currently,the coupling mechanisms at the 2D layered material-substrate interface is ambiguous,which needs greater attention.In this study,we have systematically investigated the interface coupling between monolayer WS_(2)and its supported substrates using high-temperature and high-vacuum in-situ Raman spectroscopy through monitoring the low-frequency Raman mode of monolayer WS_(2).Our findings reveal that both interfacial spacing and strain can significantly affect the coupling strength between the monolayer WS_(2)and the supported substrate.More notably,we found that the strategic introduction of appropriate interfacial strain can effectively enhance the interface coupling.Consequently,we have succeeded in achieving effective regulation of the sample-substrate coupling via a convenient way of controlling the cooling process during annealing.Our findings contribute to a deeper understanding of the coupling correlation between 2D layered materials and substrates,which is of great significance for the design and optimization of high-performance devices based on 2D layered semiconductors.

Discovery of a first-in-class ANXA3 degrader for the treatment of triple-negative breast cancer

Triple-negative breast cancer(TNBC)is a nasty disease with extremely high malignancy and poor prognosis.Annexin A3(ANXA3)is a potential prognosis biomarker,displaying an excellent correlation of ANXA3 overexpression with patients'poor prognosis.Silencing the expression of ANXA3effectively inhibits the proliferation and metastasis of TNBC,suggesting that ANXA3 can be a promising therapeutic target to treat TNBC.Herein,we report a first-in-class ANXA3-targeted small molecule(R)-SL18,which demonstrated excellent anti-proliferative and anti-invasive activities to TNBC cells.(R)-SL18 directly bound to ANXA3 and increased its ubiquitination,thereby inducing ANXA3 degradation with moderate family selectivity.Importantly,(R)-SL18 showed a safe and effective therapeutic potency in a high ANXA3-expressing TNBC patient-derived xenograft model.Furthermore,(R)-SL18 could reduce theβ-catenin level,and accordingly inhibit the Wnt/β-catenin signaling pathway in TNBC cells.Collectively,our data suggested that targeting degradation of ANXA3 by(R)-SL18 possesses the potential to treat TNBC.

Blue emitting CsPbBr3 perovskite quantum dot inks obtained from sustained release tablets

Blue emitting perovskite ink obtained from cesium lead halide quantum dots bearing chlorine(CsPbClxBr3-x,0<x<3)suffers from the low photoluminescence quantum yield and poor stability.Cesium lead bromine(CsPbBr3)quantum dots free of chlori ne have more stable crystalstructure and fewer crystal defects.Precise control of crystal sizes and surface passivation comporients of CsPbBr3 quantum dots is crucial for the best use of quantum confinement effect and blueshift of emission wavelength to blue region.Here,by polymerizing acrylamide under UV-light irradiation to form polymer gel networks in dimethyl sulfoxide(DMSO)with CsPbBr3 precursors and passivating agents trapped,wesuccessfully prepared novel sustained release tablets with different shapes and sizes.Thanks to the limitation of the polymer networks onsolve nt releasi ng,the resulting CsPbBr3 qua ntum dots have the average size of 1.1±0.2 nm.On the basis of the excelle nt quantum confin eme nteffect and optimized surface passivation,the obtained PQD ink can emit high quality blue light for more than 6 weeks.This work elucidates anew and convenient technique to prepare blue emission perovskite quantum dots ink with high stability and photoluminescence qua ntumyield and provides a great potential technology for the preparation of perovskite optoelectronic devices.

Fabrication of flower-like mesoporous TiO_2 hierarchical spheres with ordered stratified structure as an anode for lithium-ion batteries

In this study, flower-like mesoporous TiO_2 hierarchical spheres(FMTHSs) with ordered stratified structure and TiO_2 nanoparticles(TNPs) were synthesized via a facile solvothermal route and an etching reaction. Multilamellar vesicles(MTSVs) and unilamellar TiO_2/SiO_2 vesicles(UTSVs) were prepared using cetyltrimethylammonium bromide and didodecyldimethylammonium bromide as structure-directing agents under different solvothermal conditions. FMTHSs and TNPs were obtained from the etching reactions of MTSVs and UTSVs, respectively, in an alkaline system. FMTHSs display flower-like, ordered stratified structures on each petal. The thickness of the ordered stratified structure is approximately3–6 nm, and the number of layers is approximately 2–4. The FMTHSs2 electrode exhibits the first discharge capacity of 212.4 m A h g^(-1) at 0.2 C, which is higher than that of TNPs electrode(167.6 mA h g^(-1)).The discharge specific capacity of FMTHSs2 electrode after 200 cycles at 1 C is 105.9 mA h g^(-1), which is higher than that of TNPs electrode(52.2 mA h g^(-1)) after the same number of cycles. The outstanding performance of FMTHSs2 electrode is attributed to the advantages of FMTHSs. In particular, their own stratified structure can provide additional active sites for reactions. The hierarchical structure can provide short diffusion length for Li^+, large electrolyte–electrode contact area, and superior accommodation of the strain of Li+intercalation/deintercalation.

Morphology evolution of SmCox permanent magnetic nanoparticles

Sm-Co nanoparticles (NPs) are promising candidates for preparing superstable magnets and exchange-coupled nanocomposite magnets with unprecedented magnetic properties.However,the morphology evolution of the NPs remains unclear.Here,single crystalline SmCox(x=4.07,4.79,6.94,and 8.61) NPs with dimensions below the critical size of a single magnetic domain were synthesized.These NPs consist of Sm_(2)Co_(7),SmCo_(5),and Sm2Co17phases with divergent typical morphologies.An evolution model for the different morphological characteristics was proposed based on phase-structure changes and surface-energy calculations using the density functional theory.The results show that these SmCo_(4.79) NPs can be well aligned along the easy magnetization axis and exhibit an ultrahigh coercivity of 5.7 T,thus enabling to advance the control of NP morphology and to facilitate their use in superstable or nanocomposite magnets.

Optical spectroscopy study of Ca_3(Ru_(0.91)Mn_(0.09))_2O_7 single crystal in high magnetic fields

The magneto-optical spectrum, with magnetic fields up to 42 T, of double layered ruthenates Ca_3(Ru_(0.91)Mn_(0.09))_2O_7(CRMO) single crystal is studied. Both the temperature and magnetic field induced insulator-to-metal transitions(IMTs) are observed via magneto-optical properties of the crystal. The critical magnetic field(H//c) of IMT for CRMO is found to be as large as 35 T at 5 K. The fine structure of optical spectra identified the antiferromagnetic/ferro-orbital-ordering configurations of Ru 4d orbitals at low temperatures. Meanwhile, the configuration of orbital polarization of such double-layer CRMO single crystal is discussed. These results suggest that the orbital degree of freedom plays an important role in the field induced IMT of multi-orbital system.