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Thermoelectric materials (TE) have shown significant potential for power generation and localized refrigeration due to their ability to convert heat into electricity. Ca9Zn4+xSb9 is a promising TE material with low lattice thermal conductivity attributed to its complex structure and interstitial atom vacancies. However, understanding the impact of Zn vacancies in interstitial position on thermoelectric efficiencies remains a challenge. In this study, we conducted a systematic investigation of the thermoelectric properties of Ag-doped Ca9Zn4.5−xAgxSb9 (x = 0.05, 0.1, 0.15, 0.2) for the first time. Our findings reveal that increasing the occupancy rate of interstitial atoms significantly enhances electronic transport properties, thereby improving conductivity. It verifies that Ag doping pushes the Fermi level toward the valence band, indicating the metal behavior with the increase doping ratio. Through manipulation of phonon-electron decoupling, we achieved a peak zT value of ~ 0.63 at 873 K for Ca9Zn4.45Ag0.05Sb9, which is close to twice of undoped Ca9Zn4.5Sb9 with a maximum zT of about 0.37. These results not only experimentally demonstrate the promising efficiency of Ca9Zn4.45Ag0.05Sb9 but also offer a general and alternative strategy for tuning the thermoelectric properties of Zntil-phase materials through vacancy engineering. [ABSTRACT FROM AUTHOR]

Discovering more novel antimicrobial compounds has become a keen research problem. In this study, YA215 genome was sequenced by the Illumina HiSeq + PacBio sequencing platform. Genome assembly was performed by Unicycler software and the gene clusters responsible for secondary metabolite biosynthesis were predicted by antiSMASH. The genome comprised 3976514 bp and had a 46.56% G + C content. 3809 coding DNA sequences, 27 rRNAs, 86 tRNAs genes, and 79 sRNA were predicted. Strain YA215 was re-identified as Bacillus velezensis based on ANI and OrthoANI analysis. In the COG database, 23 functional groups from 3090 annotations were predicted. In the GO database, 2654 annotations were predicted. 2486 KEGG annotations linked 41 metabolic pathways. Glycosyl transferases, polysaccharide lyases, auxiliary activities, glycoside hydrolases, carbohydrate esterases, and carbohydrate-binding modules were predicted among the 127 annotations in the CAZy database. AntiSMASH analysis predicted that B. velezensis YA215 boasted 13 gene clusters involved in synthesis of antimicrobial secondary metabolites including surfactin, fengycin, macrolactin H, bacillaene, difficidin, bacillibactin, bacilysin, and plantazolicin. Three of the gene clusters (gene cluster 5, gene cluster 9, and gene cluster 10) have the potential to synthesize unknown compounds. The research underscore the considerable potential of secondary metabolites, identified in the genomic composition of B. velezensis YA215, as versatile antibacterial agents with a broad spectrum of activity against pathogenic bacteria. [ABSTRACT FROM AUTHOR]

Antibiotics are essential for combating pathogens; however, their misuse has led to increased resistance, necessitating the search for effective, low-toxicity alternatives. Surfactin, a cyclic lipopeptide with a C12-C17 β-hydroxy fatty acid chain, exhibits significant antibacterial activity and resists resistance, making it a research focus. Nonetheless, the effects of branched-chain amino acids (BCAAs) on surfactin's structure and activity are not well understood. This study examines the influence of BCAAs (L-valine, L-leucine, and L-isoleucine) on the lipopeptide (surfactin) produced by Bacillus velezensis YA215. Process optimization shows that adding 1 g/L of L-Leu and L-Ile, and 0.5 g/L of L-Val, maximized surfactin production to 18.59%, 19.23%, and 20.64%, respectively. Surfactin content peaked at 36 h with L-Val and L-Ile, yielding 19.72% and 11.37%. In contrast, L-Leu addition peaked at 24 h, yielding 11.33%. Notably, L-Val supplementation resulted in the highest relative surfactin content. Antimicrobial testing demonstrated that BCAAs significantly enhance the antibacterial effects of lipopeptides against Escherichia coli and Staphylococcus aureus, with Val showing the most pronounced effect. The addition of BCAAs notably altered the composition of surfactin fatty acid chains. Specifically, Val increased the proportions of iso C14 and iso C16 β-hydroxy fatty acids from 13.3% and 4.216–23.803% and 8.31%, respectively. Additionally, the amino acid composition at the 7th position of the peptide chain changed significantly, especially with Val addition, which increased the proportion of C14 [Val 7] surfactin by 3.29 times. These structural changes are likely associated with the enhanced antibacterial activity of surfactin. These findings provide valuable insights into the roles of BCAAs in microbial fermentation, underscoring their importance in metabolic engineering to enhance the production of bioactive compounds. [ABSTRACT FROM AUTHOR]

A good bifunctional electrocatalyst can effectively drive water splitting to produce hydrogen gas. In this paper, NiMoO4an nanomaterial was prepared and combined with black phosphorus (BP) in a one-step method. Used as a bifunctional electrocatalyst, the composite demonstrated outstanding electrochemical performance with 162.7 mV and 137.6 mV achieving current densities of 20 mA cm−2 and 10 mA cm−2 for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), respectively. For overall water splitting, the potential was just 1.55 V to achieve 10 mA cm−2, and, especially, the value only rises by0.05 V after 2000 cycles of CV. Here, the one-step synthesis method favors the dispersion of NiMoO4 nanomaterial on the BP surfaces, and facilitates a combination between the nickel molybdate and the BP. Also, the excellent performance of the samples should benefit from the synergistic action between the components. [ABSTRACT FROM AUTHOR]

Based on the excellent piezoelectric properties of 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) single crystals, a hole-doped manganite film/PMN–PT heterostructure has been constructed to achieve electric-field and light co-control of physical properties. Here, we report the resistivity switching behavior of Eu0.7Sr0.3MnO3/PMN–PT(111) multiferroic heterostructures under different in-plane reading currents, temperatures, light stimuli and electric fields, and discuss the underlying coupling mechanisms of resistivity change. The transition from the electric-field induced lattice strain effect to polarization current effect can be controlled effectively by decreasing the in-plane reading current at room temperature. With the decrease of temperature, the interfacial charge effect dominates over the lattice strain effect due to the reduced charge carrier density. In addition, light stimulus can lead to the delocalization of eg carriers, and thus enhance the lattice strain effect and suppress the interfacial charge effect. This work helps to understand essential physics of magnetoelectric coupling and also provides a potential method to realize energy-efficient multi-field control of manganite thin films. [ABSTRACT FROM AUTHOR]

Background: Hsian‐tsao gum (HG) has unique gel‐promoting and nutritional properties; however, its use in processed foods is limited to starchy foods, partially due to a lack of knowledge related to its interaction with proteins. This study elucidated the interaction mechanism of heat‐induced gelatin (G) (50 g kg−1) gel fortified with HG (0 ~ 20 g kg−1) using rheology, Fourier‐transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), large deformation tests, low‐field nuclear magnetic resonance (LF‐NMR), and confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM). Results: Heating promoted synergistic interactions between G and more HG molecules with enhanced apparent viscosity and higher storage modulus G′ than loss modulus G″, thus shortening the gel time (tg) of G‐HG sols into gels. Fourier‐transform infrared spectroscopy and DSC also confirmed the chemical interactions that occurred, facilitating the formation of β‐sheet structures of G. The microstructure of G gradually formed separate, coarse strands, and aggregated as HG was added, as observed by CLSM and SEM. This accelerated the gel formation rate and changed the textural properties. Although HG caused a disruptive decrease in the helix structure of G, it was possible to compensate for this by accelerating synergistic interactions, including depletion attractions and Maillard reactions, by heating. Conclusion: Hsian‐tsao gum interacted synergistically with G as a result of heating and this accelerated the gel formation rate and improved the gel properties. Novel complex gels could be designed by blending HG to improve the gel properties of G in the heat processing of the food gel formulation. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Anti-oxidation coatings of MoSi2-SiC-Si-ZrB2 were prepared on the graphite surface by laser cladding. The XRD, scratching bonding force, SEM and isothermal oxidation tests were used to investigate the microstructure and properties of the coatings. The coating with 40 wt% ZrB2 added (MoSi2:SiC:Si:ZrB2 = 16:4:5:16.6) has the lowest degree of oxidation, the best oxidation resistance and the highest bonding strength between coating and matrix. The scratching bonding force still maintained at about 9.9 N after laser ablation, and there were no obvious destructive defects but some pores and cracks on the coating. After a Si-enriched amorphous layer was formed, the relative oxygen permeability was significantly decreased and the oxidation of the coating was passivated, which prevented the matrix from further oxidation. [ABSTRACT FROM AUTHOR]

In this paper, α-Fe2O3 was prepared by hydrothermal and chemical precipitation methods, respectively, and its gas sensing properties toward CH4 were systematically studied. The larger specific surface area of the materials provided them potential and considerable gas adsorption abilities. The results of gas-sensing measurements indicated the synthesized α-Fe2O3 materials presented a p-type conductive nature. The sensitivities of the devices based on the different material fabrication methods were measured to be 195% and 214%, respectively, at 370°C for the concentration of 2000 ppm CH4. In addition, the sensing mechanism was discussed and simulated by first-principles calculation. The results revealed the higher surface adsorption energy of α-Fe2O3, which verified the experimental conclusions of our work. Our research suggests that α-Fe2O3 is a promising candidate for CH4 gas sensing in many fields such as mining safety and environmental monitoring. [ABSTRACT FROM AUTHOR]

Scanning and transmission electron microscopy were used to characterize the morphology of the carbon microcoils (CMCs). The Raman spectra showed that CMCs had local regular structure as ID/IG = 0.841. Then, aligned CMCs/silicone-rubber composites (5 x 5 x 1 mm³) were fabricated by coating of silicone rubber on the CMCs. Their alternating current impedance characteristics were measured as a function of applied load and the pressure sensitivity was discussed. The results showed that the impedance decreased as the increasing applied load, and the sample with less CMCs owned high pressure sensitivity, which indicated a novel composite ?lm could act as an alternative of tactile sensor. [ABSTRACT FROM AUTHOR]

The preparation process of indium oxide semiconductor nanomaterials was improved gradually, and ultimately, ordered In2O3 fibers with hollow structure were successfully synthesized by electrospinning method with a special-made collector. Compared with the other samples, the ordered sample has the biggest specific surface area, the minimum grain size, and the minimum conduction resistance. So it also has the best gas sensitivity, which is more than twice that of other samples. [ABSTRACT FROM AUTHOR]

In the last decade, with the combined application of high efficiency preparation techniques, high resolution HPLC MS/MS and sophisticated NMR technologies, novel bitter derivatives of α-, iso-α-, β-acids have been identified in beer and model solutions, which has updated our knowledge of hop chemistry. In this review, newly identified cyclic and oxidative products of α-, iso-α-, β-acids in hops and beer, have been comprehensively described to give brewers a more in depth understanding of hop and beer bitterness chemistry. A total of 39 unique substances: 15 derived from α-acids, 15 from iso-α-acids, and 9 derived from β-acids are elucidated, including their structures, suggested formation mechanism, distribution profiles in model solutions or beer, reactions during fermentation, thresholds of some of these compounds, and their evolution during storage. [ABSTRACT FROM AUTHOR]

Undoped and Na-doped ZnO thin films were fabricated by sol-gel technique on quartz glass substrates and annealed at 500°C for 1 h. The structural properties of the films were characterized using x-ray diffraction analysis, which revealed hexagonal wurtzite structure with no peaks corresponding to Na2O or other Na phases being found. Surface morphology observations by scanning electron microscopy revealed that the crystallite size and topographical properties of the ZnO films were influenced by the Na doping concentration. X-ray photoelectron spectra revealed presence of Na+ in ZnO regime. The transmittance spectra indicated that the average transmittance of Na-doped ZnO film was above 80% in the visible range, superior to that of the undoped film. There was a blue-shift in the ultraviolet absorption edge with increase of the Na content. Photoluminescence spectra illustrated two peaks, corresponding to ultraviolet near-band-edge and visible emission. [ABSTRACT FROM AUTHOR]

Four different mediums have been developed for the synthesis of PbSe nanostructures, with different size and morphology. The particles were obtained in solid state medium with size of only 60 nm on average which are much smaller than those gained in liquid and molten state mediums. The growth mechanisms of these PbSe nanostructures were discussed. Results show that the state of medium have a direct impact on the size of PbSe nanostructures and the alkalinity of environment plays a key part in the formation of PbSe nanocubes. On the other hand, the electrochemical property of two typical nanostructures was studied. In the CV curves, there are four reaction peaks corresponding to oxidation of the PbSe and Pb(OH), and the reduction of PbO and Pb(OH). Otherwise, nanorods with size of only 60 nm have greater structural stability than nanocubes. [ABSTRACT FROM AUTHOR]

The third-order nonlinear optical properties of two Au(dmit)/PMMA compound thin films, hexadecyltrimethylammonium bis(1,3-dithiole-2-thione-4,5-dithiolato)aurate and tetramethylammonium bis(1,3-dithiole-2-thione-4,5-dithiolato)aurate (abbreviated as MeAu and CtAu, respectively) with a doping concentration of 1 wt.% deposited on quartz-glass substrate were characterized by a single beam Z-scan technique at 1064 nm with 20 ps laser pulse width and 10 Hz repetition rate. The dominant nonlinear refraction and tiny nonlinear absorption of both materials lead to a larger possibility for them to be applied as promising candidates of all-optical switching. The results of two figures of merit, | W|≫1 and | T|≪1, were also calculated; this further validated the excellent properties of the materials for applications of the nonlinear optics. [ABSTRACT FROM AUTHOR]

A series of polymeric thin films with BFDT (BFDT = 4,5-bis(foroylsulfanyl)-1,3-dithiole-2-thione) doped in PMMA (polymethylmethacrylate) were fabricated by means of spin-coating on quartz substrate. The third-order nonlinear optical properties of the films were investigated by Z-scan technique at 532 nm wavelength with 20 ps pulse width. The influences of doping concentration for third-order nonlinearity were also studied. A self-defocusing effect was observed from the Z-scan curves and the nonlinear refractive index of the film increases with the increase in doping concentration. Our results suggest that considerable nonlinear optical properties were found in BFDT. In addition, it was found that the nonlinear coefficient of the BFDT-doped PMMA thin film was about two orders of magnitude larger than that of homologous materials with organic solvents. By analysis, we can conclude that the material is a potential candidate for applications of nonlinear optics and can be considered in the fabrication of all-optical switching devices, etc. [ABSTRACT FROM AUTHOR]