Action Mechanisms of Postbiotics and Their Applications in Food Field

Postbiotics are inanimate microbial cells and/or their components as well as microecological preparations made from their metabolites, which are beneficial to the health of the host. Postbiotics can regulate intestinal microbial balance, enhance immunity, and have anti-inflammatory and antibacterial effects. Compared with probiotics, living bacterial cells, postbiotics are safer, and more stable, effective and convenient. This article summarizes the origin, microbial sources, preparation methods and advantages of postbiotics, and elucidates the mechanisms of action of postbiotics in comparison with those of probiotics. In addition, it introduces readers to the applications of postbiotics as functional food supplements, food quality improvers, food preservatives and detoxifying agents in foods. We believe that as the definition, classification, and functional components of postbiotics become clearer, they will be more widely used in the fields of foods, nutraceuticals, foods for special medical purpose, infant foods, and personal care products. The development of postbiotics will also promote the leapfrog development of basic and applied science

An Fe stabilized metallic phase of NiS2 for the highly efficient oxygen evolution reaction.

This work reports a fundamental study on the relationship of the electronic structure, catalytic activity and surface reconstruction process of Fe doped NiS2 (FexNi1-xS2) for the oxygen evolution reaction (OER). A combined photoemission and X-ray absorption spectroscopic study reveals that Fe doping introduces more occupied Fe 3d6 states at the top of the valence band and thereby induces a metallic phase. Meanwhile, Fe doping also significantly increases the OER activity and results in much better stability with the optimum found for Fe0.1Ni0.9S2. More importantly, we performed detailed characterization to track the evolution of the structure and composition of the catalysts after different cycles of OER testing. Our results further confirmed that the catalysts gradually transform into amorphous (oxy)hydroxides which are the actual active species for the OER. However, a fast phase transformation in NiS2 is accompanied by a decrease of OER activity, because of the formation of a thick insulating NiOOH layer limiting electron transfer. On the other hand, Fe doping retards the process of transformation, because of a shorter Fe-S bond length (2.259 Å) than Ni-S (2.400 Å), explaining the better electrochemical stability of Fe0.1Ni0.9S2. These results suggest that the formation of a thin surface layer of NiFe (oxy)hydroxide as an active OER catalyst and the remaining Fe0.1Ni0.9S2 as a conductive core for fast electron transfer is the base for the high OER activity of FexNi1-xS2. Our work provides important insight and design principle for metal chalcogenides as highly active OER catalysts

Pharmacokinetic Comparison of Ferulic Acid in Normal and Blood Deficiency Rats after Oral Administration of Angelica sinensis, Ligusticum chuanxiong and Their Combination

Radix Angelica Sinensis (RAS) and Rhizome Ligusticum (RLC) combination is a popular herb pair commonly used in clinics for treatment of blood deficiency syndrome in China. The aim of this study is to compare the pharmacokinetic properties of ferulic acid (FA), a main bioactive constituent in both RAS and RLC, between normal and blood deficiency syndrome animals, and to investigate the influence of compatibility of RAS and RLC on the pharmacokinetic of FA. The blood deficiency rats were induced by injecting 2% Acetyl phenylhydrazine (APH) on the first day, every other day, to a total of five times, at the dosage of 100, 50, 50, 30, 30 mg/kg body mass, respectively. Quantification of FA in rat plasma was achieved by using a simple and rapid HPLC method. Plasma samples were collected at different time points to construct pharmacokinetic profiles by plotting drug concentration versus time, and estimate pharmacokinetic parameters. Between normal and blood deficiency model groups, both AUC(0–t) and Cmax of FA in blood deficiency rats after RAS-RLC extract administration increased significantly (P < 0.05), while clearance (CL) decreased significantly. Among three blood deficiency model groups, t1/2α, Vd, AUC(0–t) and AUC(0–∞) all increased significantly in the RAS-RLC extract group compared with the RAS group. The results indicated that FA was absorbed better and eliminated slower in blood deficiency rats; RLC could significantly prolong the half-life of distribution, increase the volume of distribution and the absorption amount of FA of RAS in blood deficiency rats, which may be due to the synergic action when RAS and RLC were used together to treat blood deficiency syndrome

Utilization of construction spoil and recycled powder in fired bricks

The disposal of construction spoil (CS) in landfill sites presents a significant environmental and economic concern due to the increasing amount and the associated disposal costs. This study evaluated the feasibility of utilizing recycled powder derived from construction and demolition waste for producing fired bricks. The mechanical and physical properties of fired CS bricks were characterized, and the microstructure of fired CS bricks was studied. It can be seen that the water absorption and loss on ignitions increase with the increasing RP content, while the bulk density and compressive strength exhibit the opposite trend. In addition, the maximum compressive strength of fired CS bricks is up to 16.1 MPa. The thermal conductivity of fired CS bricks decreases gradually with the increase of RP content ranging from 0 to 20 wt% and is reduced from 0.82 W/(m·K) to 0.59 W/(m·K). There is a positive effect on the increased porosity of fired CS bricks with RP, and the volume of pores increased with the increasing RP content. Therefore, CS and RP could be promising raw materials for preparing fired bricks and generating environmental benefits on a larger scale

Investigation on Nano-Self-Lubricant Coating Synthesized by Laser Cladding and Ion Sulfurization

The composite processing between laser cladding and low temperature (300°C) ion sulfurization was applied to prepare wear resistant and self-lubricating coating. The microstructure, morphology, phase composition, valence states, and wear resistance of the composite coating were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), and friction and wear apparatus. The results indicate that the laser cladding Ni-based coatings and the maximum hardness of 46.5 HRC were obtained when the percent of pure W powder was 10%, composed of columnar dendrites crystals and ultrafine dendritic structure. After ion sulfurization at 300°C for 4 h, the loose and porous composite coating is formed with nanograins and the granularity of all grains is less than 100 nm, which consists of γ-(Fe, Ni), M23C6 carbides, FeS, FeS2, and WS2. Furthermore, the wear resistance of the composite coating is better than the laser cladding Ni55 + 10%W coating, and the friction coefficient and mass losses under the conditions of dry and oil lubrication are lower than those of laser cladding Ni55 + 10%W coating

Simulation and Experiment on Droplet Formation and Separation for Needle-Type Micro-Liquid Jetting Dispenser

The needle-type droplet jetting dispenser has wide applications in the field of microelectronic packaging, and for which the good quality of droplet formation and separation is the key to successful dispensing. This paper simulates the droplet jetting process which has been divided into 5 stages named backflow, growth, droplet extension, breakage, and separation, and analyses the combined effects of system parameters, such as pressure, viscosity, needle stroke, and nozzle diameter, on the changes of morphologies of ejected droplets, which is verified by experiments. The simulation and experiment results show that a higher driving pressure is quite suitable for the high-viscosity liquid to form normal droplets by avoiding adhesion. When increasing the needle stroke, the pressure should also be lowered properly to prevent the flow-stream. Besides, the nozzle with a large diameter is much more likely to cause sputtering or satellite-droplet problems. The results have a great significance for guiding the parameter settings of the needle-type dispensing approach

Securing Fast and High-Precision Localization for Shallow Underground Explosive Source: A Curiosity-Driven Deep Reinforcement Learning Approach

Shallow underground explosive source localization technology is a key technology in the field of underground space localization. The existing approaches mainly aim to improve the localization accuracy, but need to deploy enormous sensors in the monitoring area, and rely on a large number of backend workstations to solve. These methods have the defects of considerable calculation and high time cost, and are hard to satisfy the precise and real-time requirements of onsite testing, ultimately resulting in slow localization speed and accurate localization failure. Fortunately, emerging deep reinforcement learning can effectively solve the problem of slow search policy by modeling the source localization as a Markov decision process (MDP). Therefore, a curiosity-driven deep dueling double Q-learning network (C-D3QN) is subsequently proposed to solve the above MDP. The overestimation problem is solved by decoupling selection and evaluation of the bootstrap action, and the action difference is effectively increased by introducing the dueling network that separately represents state values and action advantages. Meanwhile, the exploration is jointly reinforced by an intrinsic reward outputted from the curiosity module and an extrinsic reward supplied by the environment, guaranteeing the convergence to global optimal. Finally, extensive simulation results based on the outfield experiment data show that compared with other algorithms, the proposed scheme can significantly improve exploration ability and learning speed as well as generalization and robustness. In addition, compared to the baseline algorithm deep Q-learning network, the C-D3QN algorithm can offer an improved localization accuracy as high as 99.62&#x0025; and an increased localization speed of 66.23&#x0025;

Molecular cloning and expression analysis of a new gene for short-chain dehydrogenase/reductase 9

We report here the cloning and characterization of a novel human short-chain dehydrogenases/reductase gene SCDR9, isolated from a human liver cDNA library, and mapped to 4q22.1 by browsing the UCSC genomic database. SCDR9 containing an ORF with a length of 900 bp, encoding a protein with a signal peptide sequence and an adh_short domain. GFP localization shows SCDR9 protein concentrated in some site of the cytoplasm, but not in the ER. Expression pattern in eighteen tissues revealed that SCDR9 is expressed highly in liver. Soluble recombinant protein was successfully purified from Escherichia coli using pET28A(+) expression vector. Our data provides important information for further study of the function of the SCDR9 gene and its products

Genome-Wide Identification and Expression Analysis of Polygalacturonase Gene Family in Kiwifruit (Actinidia chinensis) during Fruit Softening

Polygalacturonase (PG) is an essential hydrolytic enzyme responsible for pectin degradation and thus plays an important role in fruit softening and other cell separation processes. PG protein is encoded by a multigene family, however, the members of PG gene family in kiwifruit (Actinidia chinensis) have not been extensively identified. In this study, a total of 51 AcPG genes in kiwifruit genome were identified. They are phylogenetically clustered into seven clades, and of them AcPG4 and AcPG18 with other known PG genes involved in fruit softening from peach, pear, papaya and melon form a small cluster together. The members of kiwifruit PG gene family consist of three to nine exons and two to eight introns, and their exon/intron structures are generally conserved in all clades except the clade D and E. During fruit softening of kiwifruit &lsquo;Donghong&rsquo; under ambient temperature, cell wall modifying enzymes, including PG, PL (pectate and pectin lyases), and PE (pectinesterase, also known as pectin methylesterase, PME) showed a different activity profile, and of them, PG and PE activities largely correlated with the change of pectin content and firmness. Moreover, only 11 AcPG genes were highly or moderately expressed in softening fruit, and of which three AcPG genes (AcPG4, AcPG18, and AcPG8, especially the former two) has been found to strongly correlate with the profile of PG activity and pectin content, as well as fruit firmness, suggesting that they maybe play an important role in fruit softening. Thus, our findings not only benefit the functional characterization of kiwifruit PG genes, but also provide a subset of potential PG candidate genes for further genetic manipulation