Sparse reconstruction of sound field using pattern-coupled Bayesian compressive sensing.

Conventional near-field acoustic holography based on compressive sensing either does not fully exploit the underlying block-sparse structures of the signal or suffers from a mismatch between the actual and predefined block structure due to the lack of prior information about block partitions, resulting in poor accuracy in sound field reconstruction. In this paper, a pattern-coupled Bayesian compressive sensing method is proposed for sparse reconstruction of sound fields. The proposed method establishes a hierarchical Gaussian-Gamma probability model with a pattern-coupled prior based on the equivalent source method, transforming the sound field reconstruction problem into recovering the sparse coefficient vector of the equivalent source strengths within the compressive sensing framework. A set of hyperparameters is introduced to control the sparsity of each element in the sparse coefficient vector of the equivalent source strengths, where the sparsity of each element is determined by both its own hyperparameters and those of its immediate neighbors. This approach enables the promotion of block sparse solutions and achieves better performance in solving for the sparse coefficient vector of the equivalent source strengths without prior information of block partitions. The effectiveness and superiority of the proposed method in reconstructing sound fields are verified by simulations and experiments.

Identification and characterization of Lacticaseibacillus rhamnosus HP-B1083-derived ß-glucuronidase and its application for baicalin biotransformation.

Baicalein, showing higher bioavailability and stronger pharmacological activity, can be obtained via a ß-glucuronidase (GUS)-catalyzed transformation of baicalein 7-O-ß-D-glucuronide (baicalin). Recently, we have found that the fermentation broth of Lacticaseibacillus rhamnosus HP-B1083 can efficiently convert baicalin to baicalein. In this study, the L. rhamnosus HP-B1083-derived enzyme involved in baicalin biotransformation was identified and characterized. First, the LruidA gene, encoding the responsible enzyme, was cloned and sequenced. Sequence analysis revealed that the deduced enzyme (designated as LrUidA) belonged to the glycosyl hydrolase family 2. The recombinant LrUidA was expressed and purified for characterization. LrUidA had a molecular weight of 70 kDa, with an optimal temperature of 50 °C and pH 4.5. Although LrUidA was susceptible to temperature, it possessed a relative pH stability. Its Michaelis-Menten constant, maximum reaction velocity and catalytic constant values were 9.710 mM, 13.08 mM/min/mg, and 14.95 s-1, respectively. Site-directed mutagenesis experiment results demonstrated that the enzyme reaction uses side chains of E509 and E415 to hydrolyze the glycosidic bond of baicalin and involves three negatively charged residues, E450, D451, and D452, respectively. Surprisingly, biotransformation was performed under optimized reaction conditions by incubating the purified enzyme with 0.1 % baicalin for 4 h, resulting in a considerable conversion ratio of 99 %. Altogether, our findings provide insights into the properties of L. rhamnosus HP-B1083-derived enzyme and expand our understanding regarding using GUS for the industrial production of baicalein.

In situ produced Co9S8 nanoclusters/Co/Mn-S, N multi-doped 3D porous carbon derived from eriochrome black T as an effective bifunctional oxygen electrocatalyst for rechargeable Zn-air batteries.

Construction of high-efficiency, low cost and stable non-noble metal catalyst on air cathode is of great importance for design and assembly of rechargeable Zn-air battery. Eriochrome black T (EBT) has phenolic hydroxyl and -N=Ν- groups, which provides multiple coordination sites for metal ions. Herein, Co9S8 nanoclusters implanted in Co/Mn-S,N multi-doped porous carbon (Co9S8@Co/Mn-S,N-PC) are fabricated with the mixture (i.e. EBT, metal precursors and dicyandiamide) by a coordination regulated pyrolysis strategy. Specifically, EBT effectively chelates with the Co and Mn ions, resulting in multiple incorporation and fine modulation of the carbon electronic structures. Meanwhile, its sulfonic acid groups are reduced at such high temperature, accompanied by simultaneously embedding S element in the carbon, ultimately in situ forming Co9S8 nanoclusters. The Co9S8@Co/Mn-S,N-PC performs as an effective bifunctional oxygen catalyst, displaying a positive half-wave potential of 0.85 V and a large limiting current density of 5.89 mA cm-2 for oxygen reduction reaction (ORR) in alkaline media, coupled with a small overpotential of 320 mV at 10 mA cm-2 towards oxygen evolution reaction (OER), outperforming commercial Pt/C and RuO2 catalysts, respectively. Furthermore, the assembled rechargeable Zn-air battery with Co9S8@Co/Mn-S,N-PC exhibits the much better charge/discharge performance and long-term durability (210 h, 630 cycles). This research opens an instructive avenue to develop high-efficient and stable bifunctional oxygen electrocatalysts in energy transformation and storage devices.

Sandwich-like superstructure of in-situ self-assembled hetero-structured carbon nanocomposite for improving electrocatalytic oxygen reduction.

Developing efficient and highly low-cost electrocatalysts for oxygen reduction reaction (ORR) is highly desirable and challenging for renewable energy devices. In this work, a novel sandwich-like heterostructured nanocomposite was facilely constructed via incorporation of Co9S8 nanoclusters/Co3[Co(CN)6]2 nanocubes in N,S-doped carbon multilayers (Co9S8/Co3[Co(CN)6]2/N,S-CMLs) by a one-pot coordination-modulated pyrolysis of a mixture containing dicyandiamide, Co(NO3)2 and Evans blue at 800 °C. The control tests demonstrated critical roles of the pyrolysis temperature played on the final morphology and shape, and discussed the formation mechanism in detail. The as-prepared catalyst exhibited appealing electrocatalytic performance for ORR with a more positive onset potential (Eonset = 0.96 V vs. RHE) and half-wave potential (E1/2 = 0.87 V vs. RHE) in 0.1 M KOH electrolyte, far outperforming other home-made catalysts and commercial Pt/C. This work opens a new avenue to prepare efficient, cost-effectiveness and stable electrocatalysts in sustainable energy storage and conversion devices.

Well entrapped platinum-iron nanoparticles on three-dimensional nitrogen-doped ordered mesoporous carbon as highly efficient and durable catalyst for oxygen reduction and zinc-air battery.

The high-performance and durable oxygen reduction reaction (ORR) catalyst on air cathode is a key component in assembly of Zn-air batteries. Herein, three-dimensional N-doped ordered mesoporous carbon (3D N-OMC) was first prepared with silica as a template via pyrolysis with assistance of dicyandiamide as a N-doping agent, combined by full adsorption of platinum (II) acetylacetonate (Pt(acac)2) and iron (II) phthalocyanine (FePc) via π-π interactions. After further pyrolysis of the resulting mixture, many PtFe nanoparticles were efficiently incorporated in 3D N-OMC (termed as PtFe@3D N-OMC for simplicity). Control experiments were certificated the important role of the pyrolysis temperature played in this synthesis. The resultant composite synergistically combines advantages of hierarchically accessible surfaces, highly open structure, and well-dispersed PtFe particles, which endow the PtFe@3D N-OMC with onset and half-wave potentials of 0.98 and 0.86 V in alkaline media, respectively, showing appealing catalytic activity for the ORR. Most significantly, the PtFe@3D N-OMC based Zn-air battery has a high power density of 80.57 mW cm-2 and long-term durability (220 h, 660 cycles). This work opens a new avenue for design of high-efficiency and durable ORR electrocatalysts in energy conversion and storage systems.

FeCo/FeCoP encapsulated in N, Mn-codoped three-dimensional fluffy porous carbon nanostructures as highly efficient bifunctional electrocatalyst with multi-components synergistic catalysis for ultra-stable rechargeable Zn-air batteries.

Currently, it is critical but a tricky point to develop economical, high-efficiency, and durable non-precious metal electrocatalysts towards oxygen reduction and oxygen evolution reaction (ORR/OER) in rechargeable Zn-air batteries. Herein, N, Mn-codoped three-dimensional (3D) fluffy porous carbon nanostructures encapsulating FeCo/FeCoP alloyed nanoparticles (FeCo/FeCoP@NMn-CNS) are prepared by one-step pyrolysis of the metal precursors and polyinosinic acid. The optimized hybrid nanocomposite (obtained at 800 °C, named as FeCo/FeCoP@NMn-CNS-800) exhibits outstanding catalytic performance in the alkaline electrolyte with a half-wave potential (E1/2) of 0.84 V for the ORR and an overpotential of 325 mV towards the OER at 10 mA cm-2. Impressively, the FeCo/FeCoP@NMn-CNS-800-assembled rechargeable Zn-air battery presents an open-circuit voltage of 1.522 V (vs. RHE), a peak power density of 135.0 mW cm-2, and long-term durability by charge-discharge cycling for 200 h, surpassing commercial Pt/C + RuO2 based counterpart. This work affords valuable guidelines for exploring advanced bifunctional ORR and OER catalysts in rational construction of high-quality Zn-air batteries.

One-step pyrolysis synthesis of nitrogen, manganese-codoped porous carbon encapsulated cobalt-iron nanoparticles with superior catalytic activity for oxygen reduction reaction.

Replacing precious metal catalysts with low-price and abundant catalysts is one of urgent goals for green and sustainable energy development. It is imperative yet challenging to search low-cost, high-efficiency, and long-durability electrocatalysts for oxygen reduction reaction (ORR) in energy conversion devices. Herein, three-dimensional low-cost Co3Fe7 nanoparticles/nitrogen, manganese-codoped porous carbon (Co3Fe7/N, Mn-PC) was synthesized with the mixture of dicyandiamide, cobalt (II) tetramethoxyphenylporphyrin (Co(II)TMOPP), hemin, and manganese acetate by one-step pyrolysis and then acid etching. The resultant Co3Fe7/N, Mn-PC exhibited excellent durability and prominent ORR activity with more positive onset potential (Eonset, 0.98 V) and half-wave potential (E1/2, 0.87 V) in 0.1 M KOH electrolyte, coupled with strong methanol resistance. The pyrolysis temperature and optimal balance of graphite with pyridine-nitrogen are of significance for the ORR performance. The prepared Co3Fe7/N, Mn-PC displayed excellent ORR performance over commercial Pt/C in the identical environment. It was ascribed to the uniform 3D architecture, Mn- and N-doping effects by finely adjusting the electronic structures, coupled with the synergistic catalytic effects of multi-compositions and multi-active sites. This work provides some constructive guidelines for preparation of low-cost and high-efficiency ORR electrocatalysts.

Cobalt nanoparticles/ nitrogen, sulfur-codoped ultrathin carbon nanotubes derived from metal organic frameworks as high-efficiency electrocatalyst for robust rechargeable zinc-air battery.

It remains a challenge for efficient and facile synthesis of promising non-noble metal electrocatalysts with outstanding properties. This work reported a simple pyrolysis method to prepare cobalt nanoparticles/nitrogen, sulfur-codoped ultrathin carbon nanotubes (Co NPs/N,S-CNTs) with metal organic frameworks (cobalt 2-methylimidazole, ZIF-67), melamine, polyvinylpyrrolidone (PVP) and thiourea. The prepared catalyst exhibited superior catalytic activity towards oxygen reduction reaction (ORR) such as the more positive onset potential of 0.96 V, half-wave potential of 0.86 V and smaller Tafel slope of 67.9 mV dec-1, outperforming those of commercial Pt/C. Furthermore, the Co NPs/N,S-CNTs based Zn-air battery not only showed good cycling performance, but also displayed a notable peak power density (153.8 mW cm-2) and large open-circuit voltage (1.433 V). This study provides some valuable guidelines for synthesizing advanced electrocatalysts in renewable energy techniques.

PTEN-induced kinase 1-induced dynamin-related protein 1 Ser637 phosphorylation reduces mitochondrial fission and protects against intestinal ischemia reperfusion injury.

BACKGROUND: Intestinal ischemia reperfusion (I/R) occurs in various diseases, such as trauma and intestinal transplantation. Excessive reactive oxygen species (ROS) accumulation and subsequent apoptotic cell death in intestinal epithelia are important causes of I/R injury. PTEN-induced putative kinase 1 (PINK1) and phosphorylation of dynamin-related protein 1 (DRP1) are critical regulators of ROS and apoptosis. However, the correlation of PINK1 and DRP1 and their function in intestinal I/R injury have not been investigated. Thus, examining the PINK1/DRP1 pathway may help to identify a protective strategy and improve the patient prognosis. AIM: To clarify the mechanism of the PINK1/DRP1 pathway in intestinal I/R injury. METHODS: Male C57BL/6 mice were used to generate an intestinal I/R model via superior mesenteric artery occlusion followed by reperfusion. Chiu's score was used to evaluate intestinal mucosa damage. The mitochondrial fission inhibitor mdivi-1 was administered by intraperitoneal injection. Caco-2 cells were incubated in vitro in hypoxia/reoxygenation conditions. Small interfering RNAs and overexpression plasmids were transfected to regulate PINK1 expression. The protein expression levels of PINK1, DRP1, p-DRP1 and cleaved caspase 3 were measured by Western blotting. Cell viability was evaluated using a Cell Counting Kit-8 assay and cell apoptosis was analyzed by TUNEL staining. Mitochondrial fission and ROS were tested by MitoTracker and MitoSOX respectively. RESULTS: Intestinal I/R and Caco-2 cell hypoxia/reoxygenation decreased the expression of PINK1 and p-DRP1 Ser637. Pretreatment with mdivi-1 inhibited mitochondrial fission, ROS generation, and apoptosis and ameliorated cell injury in intestinal I/R. Upon PINK1 knockdown or overexpression in vitro, we found that p-DRP1 Ser637 expression and DRP1 recruitment to the mitochondria were associated with PINK1. Furthermore, we verified the physical combination of PINK1 and p-DRP1 Ser637. CONCLUSION: PINK1 is correlated with mitochondrial fission and apoptosis by regulating DRP1 phosphorylation in intestinal I/R. These results suggest that the PINK1/DRP1 pathway is involved in intestinal I/R injury, and provide a new approach for prevention and treatment.