Acid-treated high-amylose corn starch suppresses high-fat diet-induced steatosis

Resistant starch (RS) has been reported to improve steatosis as well as obesity. Type 4 resistant starch (RS4), a chemically modified starch, is particularly hard to digest and suggesting higher efficacy. However, because the effects of RS4 on steatosis are not yet fully understood, the effects of RS4 on steatosis were examined using a murine high-fat diet model. Seven-week-old male mice were divided into three groups and fed a normal diet, a high-fat diet (HFD), or a high-fat diet with added RS (HFD + RS). Amylofiber SH^® produced from acid-treated corn starch was used as the dietary RS. At 22 weeks old, hepatic steatosis and short chain fatty acid (SCFA) content and gut microbiota in cecum stool samples were analyzed. The ratio of body weight to 7 weeks was significantly suppressed in the HFD + RS group compared to the HFD group (132.2 ± 1.4% vs. 167.2 ± 3.9%, p = 0.0076). Macroscopic and microscopic steatosis was also suppressed in the HFD + RS group. Analysis of cecum stool samples revealed elevated SCFA levels in the HFD + RS group compared with the HFD group. Metagenome analysis revealed that Bifidobacterium (17.9 ± 1.9% vs. 3.6 ± 0.7%, p = 0.0019) and Lactobacillus (14.8 ± 3.4% vs. 0.72 ± 0.23%, p = 0.0045), which degrade RS to SCFA, were more prevalent in the HFD + RS group than the HFD group. In conclusion, RS4 suppressed steatosis, and increased Bifidobacterium and Lactobacillus, and SCFAs. RS4 may prevent steatosis by modulating the intestinal environment.     

Fibrous MnO2 electrode electrodeposited on carbon fiber for a fuel cell/battery system

A novel fibrous MnO₂ electrode for a fuel cell/battery system is fabricated on carbon fiber by the electrodeposition method. The characteristics of the fibrous MnO₂ electrode are examined by electrochemical impedance spectra, galvanostatic performance and cyclic voltammetry. The experimental results indicate that the fibrous MnO₂ electrodes are superior to pasted electrodes because of the following: (i) better contact between MnO₂ and the electrical conducting material; (ii) high charge-transfer rate because of a smaller diameter than conventional electrodeposited MnO₂ particles (thus it is expected that the specific surface area would be higher); and (iii) a low overpotential. The morphology and the crystal structure of the fibrous MnO₂ electrode are investigated by scanning electron microscopy and X-ray diffraction, respectively. The entire surface of the carbon fiber is found to be coated with γ-MnO₂ after 2 h of electrodeposition at 0.01 A dm⁻² current density.     

Time-resolved high-speed camera observation of electrospray

A high-speed camera was implemented to visualize the time-resolved fine structure of electrospray of deionized water. This method provided useful visual information on how electrospray initiates, develops and produces water droplets of different sizes. The behavior of different spray mode and its characteristic time-scale were measured. The cone-jet mode subdivided into oscillating cone-jet, rotating cone-jet, stable cone-jet, and unstable cone-jet according to the motion and stability of cone-jet. The size of nozzle also influenced the spray mode. The stable cone-jet mode appeared over a wide range of voltage as the nozzle diameter increased. The hydrodynamic behavior of meniscus or cone-jet played a key role in determining the size of the droplets. Hydrodynamic force induced by vigorous lashing and swirling movement at the jet front was found to play a dominant role in the continuous formation of fine droplets in the cone-jet mode.     

Analysis of bis(trifluoromethylsulfonyl)imide-doped paramagnetic graphite intercalation compound using F very fast magic angle spinning nuclear magnetic resonance

F atoms bonding to paramagnetic/conductive graphene layers in accepter-type graphite intercalation compounds (GICs) are analyzed using very fast magic angle spinning nuclear magnetic resonance, which is applied for the first time on ¹⁹F nuclei to investigate paramagnetic materials. In the bis(trifluoromethylsulfonyl)imide(TFSI)-doped GIC, C–F bonds between fluorine atoms and graphene layers conform to a weak bonding of F to the graphene sheets. TFSI anions intercalated in the GIC do not show overall molecular motion; even at room temperature only the CF₃ groups rotate.     

Effect of a redox electrolyte in mixed solvents on the photovoltaic performance of a dye-sensitized solar cell

The effect of the iodide/triiodide redox electrolyte in various organic solvents on the photoelectrochemical properties of bis(tetrabutylammonium) cis-bis(thiocyanato)bis(4-carboxy-2,2′-bipyridine-4′-carboxylato)ruthenium(II)-sensitized nanocrystalline TiO₂ solar cells was studied. Solvents with large donor numbers dramatically enhanced the open-circuit voltage (V_oc), but usually reduced the short-circuit photocurrent density (J_sc). For a mixed solvent of tetrahydrofuran (THF) and acetonitrile, V_oc increased and the fill factor decreased with increasing THF concentration, but J_sc remained relatively constant. As the partial charge of the N or O atom of the solvent molecule increased, V_oc increased, but J_sc was unchanged up to a certain value of the partial charge (for THF, −0.46). For cells using 0.3 M 4-tert-butylpyridine and 20 vol% THF in the electrolyte, a short-circuit photocurrent density of 18.23 mA cm⁻², an open-circuit voltage of 0.73 V, a fill factor of 0.73, and an overall conversion efficiency of 9.74% were obtained.     

Hydrodynamic interaction between two red blood cells in simple shear flow: its impact on the rheology of a semi-dilute suspension

Blood is a suspension of red blood cells (RBCs) and its rheology is important when discussing the physiology of the cardiovascular system. In this study, we performed a numerical investigation of the rheological properties of an RBC suspension from the dilute to semi-dilute regime. RBCs were modelled as a capsule with a two-dimensional hyperelastic membrane. Large deformation of the thin membrane was calculated by a finite element method. Due to the small size of the RBC, fluid motion around the RBC was assumed to follow Stokes flow and was solved by a boundary element method. In the dilute limit, cell–cell interactions were omitted and the bulk stress of the suspension was calculated by the stresslet generated on a single RBC. Interestingly, the effective shear viscosity of the dilute suspension decreased with increasing viscosity of the internal liquid. In the semi-dilute regime, cells can be considered as showing pairwise interactions. The effective shear viscosity of the semi-dilute suspension shows a quadratic increase with respect to the volume fraction. These findings are important for understanding the complex phenomena of blood rheology.     

Formation and Control of Ultrasharp Metal/Molecule Interfaces by Controlled Immobilization of Size‐Selected Metal Nanoclusters onto Organic Molecular Films

The formation of metallic layers on ultrathin molecular films via a well‐controlled interface is essential for constructing organic nanodevices composed of metal/molecule/metal sandwich junctions. The scanning tunneling microscopy and spectroscopy studies demonstrate that an ultrasharp metal/molecule interface is realizable by depositing size‐selected Ag nanoclusters (Ag_n) from the gas phase on few‐layer films of C₆₀ molecules. It is also demonstrated that Ag_n nanoclusters can be immobilized on monolayer films of oligothiophene molecules via C₆₀ molecules, although they three‐dimensionally aggregate on bare oligothiophene films. It is also shown that electrons and holes are injected into the topmost layer of C₆₀ films via the Ag_n/C₆₀ interface. Moreover, the barrier height for carrier injection at the Ag_n/C₆₀ interface can be modified depending on the size of Ag_n nanoclusters and the kinetic energy during the deposition. The present results demonstrate that the controlled immobilization of metallic nanoclusters on molecular films can be used as a fabrication technology for metal/molecule/metal junctions.     

Synthesis of FCC Mg–Ta hydrides using GPa hydrogen pressure method and their hydrogen-desorption properties

Magnesium–tantalum ternary hydrides with an FCC structure were prepared by an ultra high-pressure technique. The FCC Mg–Ta hydride phases with the Ca₇Ge-type super-lattice structure were formed at 4 and 8 GPa. Another new phase, Mg₃TaH_y, was also verified by XRD and SEM in the specimen prepared at 8 GPa. From the temperature-programmed desorption (TPD) measurements with a heating rate of 10 K/min under vacuum, the FCC hydride exhibited hydrogen desorption of ca. 3.1 mass% at an onset temperature of 583 K. When the FCC hydride phase coexisted with Mg₃TaH_y, simultaneous decomposition occurred and the hydrogen-desorption temperature was lowered to 543 K. The hydrogen-desorption temperatures of the Mg–Ta FCC hydrides were 130–170 K lower than that of MgH₂.