Bacillus subtilis-based probiotic promotes bone growth by inhibition of inflammation in broilers subjected to cyclic heating episodes.

Heat stress as an environmental stressor causes abnormal bone remodeling and microarchitectural deterioration. The objective of this study was to investigate the effects of a Bacillus subtilis-based probiotic on bone mass of broilers subjected to cycling high ambient temperature. One hundred and twenty 1-day-old Ross 708 male broiler chicks were randomly assigned to 2 dietary treatments (12 pens per treatment): control diet and the control diet plus 250-ppm probiotic consisting of 3 strains of Bacillus subtilis. Room temperature was gradually decreased from 35°C on day 1 by 0.5°C/d until day 15, when ambient temperature was increased from 28°C to 32°C for 10 h (07:00 h-17:00 h) daily until day 44. Samples of blood, leg bones (tibia and femur), and brains (raphe nuclei and hypothalamus) were collected at day 43, while latency to lie test was conducted at day 44. Compared with controls, probiotic supplementation increased bone mineral content, weight, size, weight to length index, and reduced robusticity index in the tibia and femur (P < 0.05) of broilers subjected to heat stress. Serum concentrations of c-terminal telopeptide of type I collagen (CTX) were reduced (P = 0.02) by the probiotic supplementation, while ionized calcium, phosphate, and osteocalcin were not affected (P > 0.05). Moreover, tumor necrosis factor-α (TNF-α) in probiotic fed broilers was decreased (P = 0.003) without changes of plasma interleukin (IL)-6, IL-10, interferon-γ, and corticosterone concentrations. There were no treatment effects on the concentrations of peripheral serotonin and central serotonin and catecholamines (norepinephrine, epinephrine, and dopamine) as well as their metabolites. These results may indicate that dietary supplementation of Bacillus subtilis-based probiotic increases bone growth in broilers under a cyclic heating episode probably via inhibition of bone resorption, resulting from downregulation of the circulating TNF-α and CTX. Dietary probiotic supplementation may be a management strategy for increasing skeletal health of broilers under hot weather.

Engineering NiO/NiFe LDH Intersection to Bypass Scaling Relationship for Oxygen Evolution Reaction via Dynamic Tridimensional Adsorption of Intermediates.

Oxygen evolution reaction (OER) is a pivotal reaction in many technologies for renewable energy, such as water splitting, metal-air batteries, and regenerative fuel cells. However, this reaction is known to be kinetically sluggish and proceeds at rather high overpotential due to the universal scaling relationship, namely, the adsorption energies of intermediates are linearly correlated and cannot be optimized simultaneously. Several approaches have been proposed to break the scaling relationship by introducing additional active sites; however, positive experimental results are still absent. Herein, a different solution is suggested on the basis of dynamic tridimensional adsorption of the OER intermediates at NiO/NiFe layered double hydroxide intersection, by which the adsorption energy of each intermediate can be adjusted independently, so as to bypass the scaling relationship and achieve high catalytic performance. Experimentally, the OER overpotential is reduced to ≈205 mV at current density of 30 mA cm-2 , which represents the best performance achieved by state-of-the-art OER catalysts.

Parity-breaking in single-element phases: ferroelectric-like elemental polar metals.

Polar metals based on binary and ternary compounds have been demonstrated in literature. Here, we propose a design principle for ferroelectric-like elemental polar metals and relate it to real materials. The design principle is that, to be an elemental polar metal, atoms should occupy at least two inequivalent Wyckoff positions in a crystal with a polar space group, where inversion symmetry is spontaneously broken. According to this rule, we propose the first class of potential ferroelectric-like elemental polar metals in a distorted α-La-like structure with a polar space group P63 mc in which two inequivalent Wyckoff positions 2a (0, 0, z) and 2b (1/3, 2/3, z) are occupied by group-V elements (phosphorus, arsenic, antimony, and bismuth). Analyses based on first-principles calculations indicate that the dynamically stable polar phase results from a lone pair driven polar distortion of the nonploar phase in P63/mmc symmetry where two inequivalent Wyckoff positions 2a (0, 0, 0) and 2c (1/3, 2/3, 1/4) are occupied. This ferroelectric-like transition involves a transition from a metallic state to a semimetallic state. These predicted polar phases are metastable with respect to their corresponding ground phases. Moreover, ionic bonding characters are found due to the inequivalence in Wyckoff positions between group-V atoms. Our work opens a route to single-element parity-breaking phases.

Identifying the Key Role of Pyridinic-N-Co Bonding in Synergistic Electrocatalysis for Reversible ORR/OER.

For many regenerative electrochemical energy-conversion systems, hybrid electrocatalysts comprising transition metal (TM) oxides and heteroatom-doped (e.g., nitrogen-doped) carbonaceous materials are promising bifunctional oxygen reduction reaction/oxygen evolution reaction electrocatalysts, whose enhanced electrocatalytic activities are attributed to the synergistic effect originated from the TM-N-C active sites. However, it is still ambiguous which configuration of nitrogen dopants, either pyridinic or pyrrolic N, when bonded to the TM in oxides, predominately contributes to the synergistic effect. Herein, an innovative strategy based on laser irradiation is described to controllably tune the relative concentrations of pyridinic and pyrrolic nitrogen dopants in the hybrid catalyst, i.e., NiCo2 O4 NPs/N-doped mesoporous graphene. Comparative studies reveal the dominant role of pyridinic-NCo bonding, instead of pyrrolic-N bonding, in synergistically promoting reversible oxygen electrocatalysis. Moreover, density functional theory calculations provide deep insights into the corresponding synergistic mechanism. The optimized hybrid, NiCo/NLG-270, manifests outstanding reversible oxygen electrocatalytic activities, leading to an overpotential different ΔE among the lowest value for highly efficient bifunctional catalysts. In a practical reversible Zn-air battery, NiCo/NLG-270 exhibits superior charge/discharge performance and long-term durability compared to the noble metal electrocatalysts.

Modest Oxygen-Defective Amorphous Manganese-Based Nanoparticle Mullite with Superior Overall Electrocatalytic Performance for Oxygen Reduction Reaction.

Manganese-based oxides have exhibited high promise as noncoinage alternatives to Pt/C for catalyzing oxygen reduction reaction (ORR) in basic solution and a mix of Mn3+/4+ valence is believed to be vital in achieving optimum ORR performance. Here, it is proposed that, distinct from the most studied perovskites and spinels, Mn-based mullites with equivalent molar ratio of Mn3+ and Mn4+ provide a unique platform to maximize the role of Mn valence in facile ORR kinetics by introducing modest content of oxygen deficiency, which is also beneficial to enhanced catalytic activity. Accordingly, amorphous mullite SmMn2 O5-δ nanoparticles with finely tuned concentration of oxygen vacancies are synthesized via a versatile top-down approach and the modest oxygen-defective sample with an Mn3+ /Mn4+ ratio of 1.78, i.e., Mn valence of 3.36 gives rise to a superior overall ORR activity among the highest reported for the family of Mn-based oxides, comparable to that of Pt/C. Altogether, this study opens up great opportunities for mullite-based catalysts to be a cost-effective alternative to Pt/C in diverse electrochemical energy storage and conversion systems.

A Semi-Conductive Copper-Organic Framework with Two Types of Photocatalytic Activity.

Based on the newly designed ligand 4'-(3,5-dicarboxyphenyl)-4,2':6',4''-terpyridine (DCTP), a unique semi-conductive 3D framework {[Cu(Ι)Cu(ΙΙ)2(DCTP)2]NO3⋅1.5 DMF}n (1) with a narrow band gap of 2.1 eV, was obtained and structurally characterized. DFT calculations with van de Waals correction employed to explore the electronic structure of 1, clearly revealed its semi-conductive behavior. Furthermore, we found that 1 exhibits a superior band alignment with water to produce hydrogen and degrade organic pollutants. Without adding any photosensitizers, 1 displays an efficiently photocatalytic hydrogen production in water based on the photo-generated electrons under UV/Vis light. 1 also exhibits excellent photo-degradation of methyl blue under visible-light owing to the strong oxidization of excited holes. It is the first example of MOFs with doubly photocatalytic activities related to photo-generated electrons and holes, respectively.