Oxidation State Modulation of Bismuth for Efficient Electrocatalytic Nitrogen Reduction to Ammonia

Electrocatalytic nitrogen reduction reaction (NRR) is a promising strategy for ammonia (NH₃) production under ambient conditions. However, it is severely impeded by the challenging activation of the NN bond and the competing hydrogen evolution reaction (HER), which makes it crucial to design electrocatalysts rationally for efficient NRR. Herein, the rational design of bismuth (Bi) nanoparticles with different oxidation states embedded in carbon nanosheets (Bi@C) as efficient NRR electrocatalysts is reported. The NRR performance of Bi@C improves with the increase of Bi⁰/Bi³⁺ atomic ratios, indicating that the oxidation state of Bi plays a significant role in electrochemical ammonia synthesis. As a result, the Bi@C nanosheets annealed at 900  ° C with the optimal oxidation state of Bi demonstrate the best NRR performance with a high NH₃ yield rate and remarkable Faradaic efficiency of 15.10  ± 0.43% at − 0.4 V versus RHE. Density functional theory calculations reveal that the effective modulation of the oxidation state of Bi can tune the p-filling of active Bi sites and strengthen adsorption of *NNH, which boost the potential-determining step and facilitate the electrocatalytic NRR under ambient conditions. This work may offer valuable insights into the rational material design by modulating oxidation states for efficient electrocatalysis.     

Enhanced luminescence and energy transfer performance of double perovskite structure Gd2MgTiO6:Bi3+, Mn4+ phosphor for indoor plant growth LED lighting

Deep-red light emitting phosphors are widely used in LEDs for indoor plant growth because of the critical role played by red light in plant growth. The luminescence properties of deep-red phosphors are still not well understood at present. An energy transfer strategy is a common and effective method to improve luminescence properties. In principle, the energy transfer process may occur when the sensitizer's emission spectra overlap with the activator's excitation spectra. In this work, Bi³⁺ and Mn⁴⁺ were incorporated into the matrix of Gd₂MgTiO₆ as sensitisers and activators, respectively. Mn⁴⁺ ions tend to occupy the [TiO₆] octahedral site and the Bi³⁺ ions are expected to substituted in the site of Gd³⁺. The energy transfer process from Bi³⁺ to Mn⁴⁺ was realised and the photoluminescence (PL) intensity of Mn⁴⁺ increased with the doping content of Bi³⁺. Upon excitation at 375 nm, the PL intensity of Mn⁴⁺ increased to 116.4% when the doping concentration of Bi³⁺ reached 0.3%. Finally, the pc-LED devices were prepared by a Gd₂MgTiO₆:Bi³⁺, Mn⁴⁺ phosphor. The high red luminescence indicated that this phosphor has potential applications in indoor LED lighting.     

Magnetic porous nano-carbon catalysts supported silver nanoparticles derived from chitin and their application in catalytic reduction reactions

The exploitation of recycled carbonaceous catalysts from renewable biomass resources such as chitin is a crucial issue for the development of the sustainable society. In this article, the chitin-based N and O doped carbon microspheres (ChC) were fabricated by a simple dissolution, sol–gel transformation, and the carbonization methods. Subsequently, the novel magnetic Ag-Fe₃O₄@chitin-based carbon microspheres catalyst (MChC) was successfully constructed through the in situ redox reaction. The as-prepared MChC possessed rich micropores with high-surface area, and a narrow size distribution (50–120 μm). The Ag-Fe₃O₄ nanoparticles were immobilized through the interaction with C, N, and O atoms in the pores of MChC. The reduction of 4-nitrophenol was applied to evaluate the catalytic activity of MChC. 4-Nitrophenol (4-NP) could be fully reduced to 4-aminophenol (4-AP) in 5 min with the catalyst MChC-45. Moreover, MChC could be collected in solution with an external magnet in 8 s and remained relatively high-catalytic activity after 10 cycle times. This work provided novel ideas for the fabrication of doped carbon material from biomass and promoted its utilization in nanocatalytic applications.     

High energy storage and ultrafast discharge in NaNbO3-based lead-free dielectric capacitors via a relaxor strategy

Dielectric capacitors with decent energy storage and fast charge-discharge performances are essential in advanced pulsed power systems. In this study, novel ceramics (1-x)NaNbO₃-xBi(Ni_2/3Nb_1/3)O₃(xBNN, x = 0.05, 0.1, 0.15 and 0.20) with high energy storage capability, large power density and ultrafast discharge speed were designed and prepared. The impedance analysis proves that the introducing an appropriate amount of Bi(Ni_0·5Nb_0.5)O₃ boosts the insulation ability, thus obtaining a high breakdown strength (E_b) of 440 kV/cm in xBNN ceramics. A high energy storage density (W_total) of 4.09 J/cm³, recoverable energy storage density (W_rec) of 3.31 J/cm³, and efficiency (η) of 80.9% were attained in the 0.15BNN ceramics. Furthermore, frequency and temperature stability (fluctuations of W_rec ≤ 0.4% over 5–100 Hz and W_rec ≤ 12.3% over 20–120 °C) were also observed. The 0.15BNN ceramics exhibited a large power density (19 MW/cm³) and ultrafast discharge time (~37 ns) over the range of ambient temperature to 120 °C. These enhanced performances may be attributed to the improved breakdown strength and relaxor behavior through the incorporation of BNN. In conclusion, these findings indicate that 0.15BNN ceramics may serve as promising materials for pulsed power systems.     

Improving Strategies in the Development of Protein-Downregulation-Based Antiandrogens

The androgen receptor (AR) plays a crucial role in the occurrence and development of prostate cancer (PCa), and its signaling pathway remains active in castration-resistant prostate cancer (CRPC) patients. The resistance against antiandrogen drugs in current clinical use is a major challenge for the treatment of PCa, and thus the development of new generations of antiandrogens is under high demand. Recently, strategies for downregulating the AR have attracted significant attention, given its potential in the discovery and development of new antiandrogens, including G-quadruplex stabilizers, ROR-γ inhibitors, AR-targeting proteolysis targeting chimeras (PROTACs), and other selective AR degraders (SARDs), which are able to overcome current resistance mechanisms such as acquired AR mutations, the expression of AR variable splices, or overexpression of AR. This review summarizes the various strategies for downregulating the AR protein, at either the mRNA or protein level, thus providing new ideas for the development of promising antiandrogen drugs.     

武汉市一般人群血清中全氟及多氟烷基化合物浓度及其影响因素研究

目的 了解武汉市一般人群血清中全氟及多氟烷基化合物(PFASs)浓度,探索血清中PFASs浓度水平的影响因素。方法 以在武汉市某医院进行一般体检的人群为研究对象(n=67),通过超高效液相色谱-三重四级杆质谱(UPLC-TQ/MS)联用仪测定外周血清中12种PFASs浓度,采用多元线性回归分析方法分析一般人口学特征和血清中PFASs浓度的关联性。结果 武汉市一般人群血清中12种PFASs的平均浓度水平为11.60 ng/mL。全氟辛烷磺酸及其盐类(PFOS)和全氟辛酸及其盐类(PFOA)的贡献率较大,分别为45.03%和31.86%。男性人群血清中PFOS、PFOA、全氟己基磺酸(PFHxS)、全氟壬酸(PFNA)等主要化合物的浓度高于女性,其β值(95%可信区间)分别为0.708(0.313,1.104)、0.518(0.069,0.967)、0.724(0.388,1.059)和0.684(0.399,0.968)。同时,发现血清中PFOS、PFHxS、PFNA浓度和年龄呈正相关,其β值(95%可信区间)分别为0.062(0.042,0.081)、0.035(0.019,0.052)和0.030(0.016,0.045)。结论 性别和年龄对血清中PFASs浓度有影响,在进行人体PFASs暴露评估中应考虑这些因素。     

Preconditioned method for the nonlinear complex Ginzburg–Landau equations

Wireless Networks - In this work, we give an effective preconditioned numerical method to solve the discretized linear system, which is obtained from the space fractional complex...     

Uniform α-Fe2O3 nanoparticles with narrow gap immobilized on CNTs through N-doped carbon as high-performance lithium-ion batteries anode

Fe₂O₃ with high theoretical capacity, low cost, and environmental friendliness has been attracted great attention in lithium-ion batteries (LIBs), which however is limited by low rate capability and fast capacity fading owing to low electronic conductivity, self-aggregation, and sever volume expansion. CNTs with excellent conductivity and unique 3D interconnected network are ideal matrices for composite electrochemical materials, but it is difficult to meet the demand of high capacity. Here, uniform α-Fe₂O₃ nanoparticles with narrow gap (~1.4 nm) were immobilized on CNTs through N-doped carbon (α-Fe₂O₃/CNTs-NC) that can address these issues. As an advanced LIBs anode, the electrode displays unprecedented specific capacity (1173 mAh/g at 0.2 A/g) and outstanding rate behavior (716.4 mAh/g at 5.0 A/g after 1200 cycles), which are even superior to the theoretical capacity (1007 mAh/g) and the performance of most reported Fe₂O₃-based anodes. Homogeneous nano-sized α-Fe₂O₃ with a narrow gap highly shortens the diffusion path for Li⁺ transport, exposes quite sufficient active sites, and prevents the volume change. Moreover, the 3D backbone of CNTs with a more homogeneously distributed electric field can enhance conductivity, and tightly contact with α-Fe₂O₃ by NC, then obtain robust structural stability, which boosts LIBs in storage capacity, rate capability, and cycling stability.     

Effect of Y concentration and film thickness on microstructure and electrical properties of HfO2 based thin films

In this work, we introduced a simple solution processing method to prepare yttrium (Y) doped hafnium oxide (HfO₂) based dielectric films. The films had high densities, low surface roughness, maximum permittivity of about 32, leakage current < 1.0 × 10^?7 A/cm² at 2 MV/cm, and breakdown field >5.0 MV/cm. In addition to dielectric performance, we investigated the influence of YO_1.5 fraction on the electronic structure between Y doped HfO₂ thin films and silicon (Si) substrates. The valence band electronic structure, energy gap and conduction band structure changed linearly with YO_1.5 fraction. Given this cost-effective deposition technique and excellent dielectric performance, solution-processed Y doped HfO₂ based thin films have the potential for insulator applications.     

Inhibiting effect of heterogeneous cations aggregation enhanced by oxygen deficiency on glass formation of BaTi2O5 melts

Although remarkable development of titanate-based glasses has been achieved, challenge remains to elucidate the correlation between structure and glass-forming properties in these systems due to their complex structure that is inconsistent with the classic Zachariasen's model. In this work, we aim to correlate the structural evolution of titanate melts to their glass-forming ability (GFA). The prototypical material barium dititanate (BaTi₂O₅, BT2) melts with different GFA were rendered by controlled melting atmospheres, and the corresponding structural changes were determined using in situ high-energy synchrotron X-ray diffraction combined with empirical potential structure refinement and ab initio molecular dynamics. The results show that BT2 melt in reducing atmosphere shows poor GFA but that in oxidizing atmosphere presents good GFA. Structural analysis demonstrates the mean coordination number of [TiO_m] polyhedra is analogous in the melt under two different atmospheres but an enhanced heterogeneous cations aggregation takes place in the melt under reducing atmosphere, which is closely related to oxygen-deficiencies. Furthermore, we reveal that the enhanced heterogeneous cations aggregation promotes crystallization (and therefore hinders glass formation) through disordering the distribution of [TiO_m] and [BaO_n] polyhedra, changing the connectivity between these polyhedra, creating more crystal-like Ti-Ti clusters, and decreasing topological disorder of BT2 melt. Our work provides a new viewpoint to understand the GFA of titanates melt from structural heterogeneity beyond the previous perspectives that only focus on [TiO_m] polyhedra.