Isolated Diatomic Ni-Fe Metal-Nitrogen Sites for Synergistic Electroreduction of CO2

Polynary single‐atom structures can combine the advantages of homogeneous and heterogeneous catalysts while providing synergistic functions based on different molecules and their interfaces. However, the fabrication and identification of such an active‐site prototype remain elusive. Here we report isolated diatomic Ni‐Fe sites anchored on nitrogenated carbon as an efficient electrocatalyst for CO2 reduction. The catalyst exhibits high selectivity with CO Faradaic efficiency above 90 % over a wide potential range from −0.5 to −0.9 V (98 % at −0.7 V), and robust durability, retaining 99 % of its initial selectivity after 30 hours of electrolysis. Density functional theory studies reveal that the neighboring Ni‐Fe centers not only function in synergy to decrease the reaction barrier for the formation of COOH* and desorption of CO, but also undergo distinct structural evolution into a CO‐adsorbed moiety upon CO2 uptake.This research was undertaken with the assistance of resources provided by the National Computing Infrastructure (NCI) facility at the Australian National University allocated through both the National Computational Merit Allocation Scheme supported by the Australian Government and the Australian Research Council grant LE160100051 (Maintaining and enhancing merit-based access to the NCI National Facility, 2016–2018). This work was supported by the Australian Research Council (DP160103107, FT170100224)

Design and analysis on fume exhaust system of blackbody cavity sensor for continuously measuring molten steel temperature

Fume exhaust system is the main component of the novel blackbody cavity sensor with a single layer tube, which removes the fume by gas flow along the exhaust pipe to keep the light path clean. However, the gas flow may break the conditions of blackbody cavity and results in the poor measurement accuracy. In this paper, we analyzed the influence of the gas flow on the temperature distribution of the measuring cavity, and then calculated the integrated effective emissivity of the non-isothermal cavity based on Monte-Carlo method, accordingly evaluated the sensor measurement accuracy, finally obtained the maximum allowable flow rate for various length of the exhaust pipe to meet the measurement accuracy. These results will help optimize the novel blackbody cavity sensor design and use it better for measuring the temperature of molten steel

Optimization of Operating Parameters for Coal Low-Temperature Ashing: A Suitable and Efficient Treatment Method for Mineral Analysis in Coal

Low-temperature oxygen-plasma ashing plus X-ray diffraction analysis is one of the effective techniques to identify minerals in coal. However, previous publications have not provided any details of the exact low-temperature degrees and corresponding working conditions of ashers, and this could lead to two adverse effects without proper operating guidance: (1) a relatively high temperature (e.g., >150 °C) may cause alteration of minerals (particularly clay minerals), and (2) a relatively low temperature (e.g., (004) and kaolinite d(002) can be clearly distinguished by LTAs-XRD analysis. In addition, different low temperatures have certain influence on the crystal structure of minerals. When the power rises to above 300 W (about 150 °C), the crystal structure of minerals undergoes changes. The symmetry and integrity of the mineral peaks became worse, and destructive interference occurred between the spacing of reflection planes, resulting in significant decrease in diffraction peak intensity; thus, some trace minerals were unable to be identified. The study on the working parameters of the instrument would be helpful to ash coals more effectively and make qualitative and quantitative analysis of minerals more accurate

Effect of different Lactobacillus

Lactobacillus is the dominant genus during fruit and vegetable juices (FVFs) fermentation, which are the key factors for taste and flavor. This study was performed to investigate the effects of different Lactobacillus spp. on profile of volatile flavor compounds and nonvolatile taste compounds in FVFs fermentation. A total of 14 compounds were identified as discriminant flavor and taste markers for fermented FVFs via gas chromatography–mass spectrometry (GC‐MS)‐based multimarker profiling. The PCA score plot and PLS‐DA showed that different FVFs were divided into three distinct types, suggesting that the different species significantly affect the volatile and nonvolatile compounds profiles of FVFs. Lactobacillus casei and Lactobacillus rhamnosus (Type A FVFs) might make a greater contribution to the umami taste. Lactobacillus plantarum and Lactobacillus acidophilus (Type B FVFs) make a greater contribution to the sour taste. Lactobacillus fermentum may be an potential critical contributor to produce volatile compounds. We reveal that different Lactobacillus strains play different roles in modifying these compounds related to flavor and taste features

Effect of different Lactobacillus species on volatile and nonvolatile flavor compounds in juices fermentation

Lactobacillus is the dominant genus during fruit and vegetable juices (FVFs) fermentation, which are the key factors for taste and flavor. This study was performed to investigate the effects of different Lactobacillus spp. on profile of volatile flavor compounds and nonvolatile taste compounds in FVFs fermentation. A total of 14 compounds were identified as discriminant flavor and taste markers for fermented FVFs via gas chromatography–mass spectrometry (GC‐MS)‐based multimarker profiling. The PCA score plot and PLS‐DA showed that different FVFs were divided into three distinct types, suggesting that the different species significantly affect the volatile and nonvolatile compounds profiles of FVFs. Lactobacillus casei and Lactobacillus rhamnosus (Type A FVFs) might make a greater contribution to the umami taste. Lactobacillus plantarum and Lactobacillus acidophilus (Type B FVFs) make a greater contribution to the sour taste. Lactobacillus fermentum may be an potential critical contributor to produce volatile compounds. We reveal that different Lactobacillus strains play different roles in modifying these compounds related to flavor and taste features

Screening of Microbial Strains Used to Ferment <i>Dendrobium officinale</i> to Produce Polysaccharides, and Investigation of These Polysaccharides’ Skin Care Effects

The microbial fermentation of plants is a promising approach for enhancing the yield of polysaccharides with increased activity. In this study, ten microbial strains, Lactiplantibacillus plantarum CCFM8661, Limosilactobacillus reuteri CCFM8631, Lactobacillus helveticus M10, Lacticaseibacillus rhamnosus CCFM237, Lactilactobacillus sakei GD17-9, Lacticaseibacillus casei CCFM1073, Bacillus subtilis CCFM1162, Bacteroides cellulosilyticus FTJSI-E-2, Bacteroides stercoris FNMHLBEIK-4, and Saccharomyces cerevisiae HN7-A5, were used to ferment Dendrobium officinale. The skin care activity of the resulting polysaccharides (F-DOP) was evaluated in cultured HaCaT and RAW 264.7 cells, and a mouse model. The results indicated that D. officinale medium promoted strain proliferation, and fermentation significantly enhanced polysaccharide yield (up to 1.42 g/L) compared to that without fermentation (0.76 g/L). Moreover, F-DOPs, especially after CCFM8631 fermentation, exhibited an excellent ability to attenuate sodium dodecyl sulfate-induced HaCaT cell injury (from 69.04 to 94.86%) and decrease nitric oxide secretion (from 42.86 to 22.56 μM) in lipopolysaccharide-stimulated RAW 264.7 cells. In vivo, CCFM8631-FDOP reduced the transdermal water loss rate, skin epidermal thickness, and interleukin 6, and enhanced the expression of filaggrin, improving 2,4-dinitrofluorobenzene-induced skin damage. Therefore, considering viable cell counts, polysaccharide yields, and skin care efficacy in vitro and in vivo, CCFM8631 is the most suitable strain to enhance the skin care activity of DOPs and possesses promising potential for applications in the cosmetics industry

Comparative Genomic Analysis of Lactiplantibacillus plantarum Isolated from Different Niches

Lactiplantibacillus plantarum can adapt to a variety of niches and is widely distributed in many sources. We used comparative genomics to explore the differences in the genome and in the physiological characteristics of L. plantarum isolated from pickles, fermented sauce, and human feces. The relationships between genotypes and phenotypes were analyzed to address the effects of isolation source on the genetic variation of L. plantarum. The comparative genomic results indicate that the numbers of unique genes in the different strains were niche-dependent. L. plantarum isolated from fecal sources generally had more strain-specific genes than L. plantarum isolated from pickles. The phylogenetic tree and average nucleotide identity (ANI) results indicate that L. plantarum in pickles and fermented sauce clustered independently, whereas the fecal L. plantarum was distributed more uniformly in the phylogenetic tree. The pan-genome curve indicated that the L. plantarum exhibited high genomic diversity. Based on the analysis of the carbohydrate active enzyme and carbohydrate-use abilities, we found that L. plantarum strains isolated from different sources exhibited different expression of the Glycoside Hydrolases (GH) and Glycosyl Transferases (GT) families and that the expression patterns of carbohydrate active enzymes were consistent with the evolution relationships of the strains. L. plantarum strains exhibited niche-specific characteristicsand the results provided better understating on genetics of this species