Real-time ellipsometric characterization of the initial growth stage of poly(3,4-ethylene dioxythiophene): poly(styrene sulfonic acid) films by electrospray deposition

Kinetic spectroscopic ellipsometry have been used to study the initial growth stage of poly(3,4-polyethylene dioxythiophene):poly(styrenesulfonic acid)(PEDOT:PSS) films by the electrospray deposition (ESD) method. The real-time spectra analysis revealed that the surface overlayer decreased in thickness once the first bulk layer monolayer was formed, indicating a smoothening effect as the nucleation-related microstructure coalesced into the bulk layer. Once the coalescence was completed and the nucleation-induced surface roughness layer was stabilized, the underlying bulk layer increased linearly with time. These results originate from the degrees of the evaporation of solvent material during the transferring the precursors to the surface and/or of the diffusion of deposition precursors after sticking at the growing surface.     

Chemical activity of oxygen atoms in the magnetron sputter-deposited ZnO films during film growth

The role of oxygen atoms in the growth of magnetron sputter-deposited ZnO films was studied in a deposition and post-deposition study in which the deposition of a several-nanometer-thick ZnO layer altered with an exposure to an O2/Ar mixed plasma, i.e., a layer-by-layer (LbL) technique. The film crystallization was promoted by suppressing the oxygen vacancy and interstitial defects by adjusting the exposure conditions of the O2/Ar plasma. These findings suggest that the chemical potential of the oxygen atom influences the film crystallization and the electronic state. The diffusion and effusion of oxygen atoms at the growing surface have an effect similar to that of thermal annealing, promoted film crystallization and the creation and the annihilation of oxygen- and zinc-related defects. The role of oxygen atoms reaching the growing film surface is discussed in terms of chemical annealing and a possible oxygen diffusion mechanism is proposed.     

Origin of Surface Coating Effect for MgO on LiCoO2 to Improve the Interfacial Reaction between Electrode and Electrolyte

Surface coating on lithium‐ion battery cathodes improves their durability at high potentials, which is a well‐known practical application. However, the mechanism is still unclear because the coating influences the electrode/electrolyte interface at a few nanometer‐scale and direct observation of the interface under real operating conditions of a battery is challenging. This study reveals the mechanism of the surface coating effect on lithium‐ion battery cathodes by using in operando X‐ray absorption spectroscopy (XAS) on well‐defined MgO‐coated LiCoO₂ thin‐film electrodes prepared via pulsed laser deposition. Total‐reflection in operando XAS measurements reveal that LiCoO₂ forms a reductive phase at the interface between the uncoated‐LiCoO₂ electrode and the electrolyte, while the MgO coating layer inhibits the redox process, leading to an improvement in the cycle performance of the battery. Depth‐resolved in operando XAS measurements indicate that a solid solution of the magnesium phase forms at the LiCoO₂ surface upon MgO coating. Magnesium ions function as pillars to stabilize the layered structure at the interface between the LiCoO₂ electrode and the electrolyte for delithiated states upon cycling at potentials.     

Application of ion-trap LC/MS/MS for determination of acrylamide in processed foods

Ion-trap LC/MS/MS was evaluated for use in the determination of acrylamide (AA) in processed foods. Multiple reaction monitoring (MRM) analysis of a series of AA standard solutions containing deuterium-labeled acrylamide (AA-d3) as an internal standard was performed. A linear relationship between the concentration of AA and the ratio of peak area (AA/AA-d3) in the extracted ion chromatogram (m/z 55, 58 derived from m/z 72, 75, respectively) was obtained over a wide range of 2-20,000 ng/mL. The quantification limit of AA was 2 ng/mL. In analyses of 37 commercial foods, AA was detected in a potato snack at the maximum value of 3,570 ng/g and found in 23 foods prepared or cooked at high temperature. The samples were analyzed in triplicate and the relative standard deviations (RSD) were less than 15% in many processed foods.     

Physicochemical Property of Huaishan (Rhizoma Dioscorea) and Matai (Eleocharis dulcis) Starches

The physicochemical properties of starch, the main component in tuberous root of Huaishan (Rhizoma Dioscorea) and corm of Matai (Eleocharis dulcis) was investigated and compared with those of a Japanese yam, “Yamanoimo” starch, and potato starch. Mean particle sizes of Huaishan and Matai starches were 24 ± 5 μm and 12 ± 5 μm, respectively. X-Ray diffraction pattern suggests that Huaishan starch was B-type or C-type just close to B-type and Matai starch was A-type or C-type just close to A-type. Apparently, the intermediate component (IntCom) of Huaishan starch, which was obtained by fractionation of the starch into amylose and amylopectin, may still contain amylose and amylopectin. IntCom of Matai starch has an intermediate nature between amylose and amylopectin. It is concluded that the amylopectin molecules of Huaishan starch contain a larger amount of longer branch-ed chains and those of Matai starch contain a larger amount of shorter branched chains. Amylograms of Matai and Huaishan starches suggest that the gelatinized starches are difficult to retrograde. Digestibility of Huaishan starch by an α-amylase was the highest among the tested starches.     

Comparison of antimicrobial resistance between the type strain of Lactococcus lactis and isolates from coastal environments

To ensure the safety of dairy products, a comparison was made between coastal-derived Lactococcus lactis strains and the type strain regarding antimicrobial resistance (AMR) and their genes. The test discs revealed that the AMR of 31 strains against streptomycin, gentamicin and kanamycin was higher than that of the type strain. The clear zone ratio of the type strain to that of Himuka-SU2 was 3.0–3.5. However, both strains exhibited identical AMR genes. Pre-incubation in broth containing 3.4% (w/v) NaCl increased the AMR of the type strain compared to the Himuka-SU2 strain. These results are significant for the development of starters for fermented milk.