High‐fat Diet‐induced Intestinal Hyperpermeability is Associated with Increased Bile Acids in the Large Intestine of Mice

Metabolic syndrome is characterized by low‐grade chronic systemic inflammation, which is associated with intestinal hyperpermeability. This study examined the effects of 3 high‐fat diets (HFDs) composed of different fat sources (soybean oil and lard) on the intestinal permeability, tight junction (TJ) protein expression, and cecal bile acid (BA) concentrations in mice, and then analyzed their interrelations. C57/BL6 mice were fed the control diet, HFD (soybean oil), HFD (lard), and HFD (mix; containing equal concentrations of soybean oil and lard) for 8 wk. Glucose tolerance, intestinal permeability, TJ protein expression, and cecal BA concentration were evaluated. Feeding with the 3 HDFs similarly increased body weight, liver weight, and fat pad weight, and induced glucose intolerance and intestinal hyperpermeability. The expression of TJ proteins, zonula occludens‐2 and junctional adhesion molecule‐A, were lower in the colons of the 3 HFD groups than in the control group (P < 0.05), and these changes appeared to be related to intestinal hyperpermeability. Feeding with HFDs increased total secondary BA (SBA) and total BA concentrations along with increases in some individual BAs in the cecum. Significant positive correlations between intestinal permeability and the concentrations of most SBAs, such as deoxycholic acid and ω‐muricholic acids, were detected (P < 0.05). These results suggest that the HFD‐induced intestinal hyperpermeability is associated with increased BA secretion. The abundance of SBAs in the large intestine may be responsible for the hyperpermeability.     

Coexisting phenomena of surge and rotating stall in an axial flow compressor

The unsteady inner flow structure of a single-stage axial flow compressor under the coexisting conditions of surge and rotating stall was experimentally investigated via detailed measurements of the unsteady characteristics and the internal flow velocity fluctuations. The main relevant feature of the tested compressor is a shock tube with a capacity tank connected in series to the compressor outlet through slits and a concentric duplex pipe： surge and rotating stall can both be generated by connecting the shock tube. Research attention is focused on the unsteady behavior of a rotating stall during the surge cycle. The size of the rotating stall cell during the recovery process of an irregular surge cycle was experimentally determined by the circumferential flow velocity fluctuations ahead of the rotor blade. The results suggested that the size of the rotating stall cell at the switching point of the performance curve between large and small cycles is considered to be the key parameter in determining the following surge cycle. In addition, the surge cycle is largely influenced by the unsteady behavior of the rotating stall cell.     

Exchange rate constants of invisible protons in proteins determined by NMR spectroscopy

Although labile protons that are exchanging rapidly with those of the solvent cannot be observed directly, their exchange rate constants can be determined by indirect detection of scalar-coupled neighboring nuclei. We have used heteronuclear NMR spectroscopy to measure the exchange rate constants of labile protons in the side chains of lysine and arginine residues in ubiquitin enriched in carbon-13 and nitrogen-15 at neutral pH. Exchange rate constants as fast as 40x10(3) s(-1) were thus measured. These results demonstrate that NMR spectroscopy is a powerful tool for the characterization of lysine NH3(+) and arginine NH groups in proteins at physiologically relevant pH values.     

Formation of gas barrier films by Cat-CVD method using organic silicon compounds

Silicon nitride (SiN_x) and silicon oxynitride (SiO_xN_y) films have been formed by catalytic chemical vapor deposition (Cat-CVD) method using hexamethyldisilazane (HMDS). Addition of NH₃ gas and increase in gas pressure can prevent carbonization of tungsten (W) catalyzer. These SiO_xN_y films have high gas barrier ability compare to the case of SiO_xN_y films using SiH₄ and thus are expected for novel sealing films.     

Measurement of tongue–artificial nipple contact pressure during infant sucking

To clarify the motor function of the infant tongue during sucking, we developed an artificial nipple that contained multiple small built‐in force sensors integrated with a PC‐based system which is capable of measuring tongue–artificial nipple contact pressures in real time. The force sensor is a cantilever structure with a small, thin stainless steel beam where an all‐purpose foil strain gauge is attached to the surface of the beam. An artificial nipple made of an elastomer containing these sensors is connected through an amplifier and an A/D converter to a PC via a USB port. Using this system, measurements were taken in three infants whose oral feeding was well established and in one infant of low birth weight. The results from each force sensor showed a pressure waveform of a nearly simple harmonic motion that indicated a peristalsis‐like movement of the tongue; the sucking frequency was found to be about two times per second. In addition, in the low‐birth‐weight infant, the pressure changed as the infant grew. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Catalytic activity of yeast extract in biofuel cell

It was revealed that the dry powder yeast extract (YE) has the ability to act as a biocatalyst as well as a mediator in a biofuel cell. The yeast extract, from Nihon Pharmaceutical Co., Ltd., was used as a biocatalyst in an open air cathode biofuel cell containing phosphate buffer for glucose oxidation. The anode medium with only the YE showed an immediate activity by producing a current and delivering power depending on its concentration. By adding glucose to the anode medium, the anode potential decreased with time to -0.2?V vs. normal hydrogen electrode (NHE), and produced a higher power compared to that without glucose. The biofuel cell produced an open circuit voltage (OCV) as high as 1?V.     

Behavior of the high frequency Raman modes of double-wall carbon nanotubes after doping with bromine or iodine vapors

The effects of two different halogen dopants (bromine and iodine) at different concentrations on the higher frequency modes (the so-called G and G′ bands) of the Raman spectra of double-wall carbon nanotube (DWCNT) “buckypaper” are investigated. The effects of dopants on different DWCNT configurations (metallic inner/semiconducting outer and vice versa) are studied by changing the laser excitation energy. The doping causes the loss of the Breit–Wigner–Fano line shape and the appearance of less metallic behavior. An increase of the relative intensity of the G⁺ band, which is more sensitive for the outer metallic tubes, is clearly observed with increasing Br₂ concentration in the sample. By analysis of the G⁺ band and the G′ band it is possible to measure the changes in the electron–phonon coupling, due to the charge-transfer between the dopant (Br₂ or I₂) and the tubes in the DWCNT. The doping effect causes an upshift of the G⁺ band and a suppression of the contribution of the inner tubes to the G′ band signal and as a consequence, the observed G′ band is dominated by the contribution from the outer tubes.     

Preparation of polyynes by liquid-phase laser ablation using different irradiation target materials and solvents

Polyynes were prepared from pellets of a perylene derivative, 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA), and graphite by liquid-phase laser ablation, using solvents of methanol, ethanol, 1-propanol, 1-butanol, t-butyl alcohol, n-hexane, and decalin. The amounts of polyynes produced from PTCDA strongly depended on the polarity of the solvent, while those from graphite did not. Polar functional groups of acid-anhydride side chains in PTCDA are believed to influence the amounts of C₂ radicals produced by laser ablation. The long-chain polyyne C₂₈H₂ was detected in a chromatogram of a solution obtained from a graphite pellet and solvent decalin.     

Glass capillary optics for producing nanometer sized beams and its applications

We have developed a method to produce micro/nano meter sized beams of keV energy highly charged ions (HCIs) and MeV energy protons/He ions with tapered glass capillary optics for application of surface modifications and a biological tool called “cell surgery”, respectively. The transmission through the tapered glass capillaries with inlet diameter of 0.8 mm?, outlet diameter from 900 nm? to several tens of microns and length of about 50 mm was performed using 8/64 keV Ar⁸⁺ beams. The transmitted beams had a density enhancement of about 10 and were guided through a capillary tilted by as large as ±100 mrad. The charge state of the beams was kept during the transmission. The combination of MeV proton/He ion beams and the capillary with a thin end window at its outlet can realize pinpoint energy deposition and three-dimensional selection of the bombarding point in an arbitrary position of a living cell or in any liquid object. We demonstrated that a real biological cell, HeLa cell with the nucleus labeled by green fluorescent protein (GFP), was irradiated with the microbeam, which was prepared by 4 MeV He²⁺ entering a capillary with an end window of 7.3 μm in thickness and outlet diameter of 9.6 μm?. The transmitted MeV ion beams had density enhancement up to 1000 according to the capillary outlet sizes, which are applicable to various material analyses employing microbeams.