Arterial oxygen desaturation during non-sedated diagnostic upper gastrointestinal endoscopy

We studied oxygen saturation (SaO2) using a pulse oximeter in 120 patients undergoing non-sedated diagnostic upper gastrointestinal endoscopy. The baseline SaO2 was 98.3 +/- 1.0%. During the procedure, absence of oxygen desaturation (SaO2 > or = 95%) was found in 56%, mild oxygen desaturation (95% > SaO2 > or = 90%) in 35%, and severe oxygen desaturation (SaO2 < 90%) in 9%. Age (p = 0.56), gender (p = 0.47), smoking (p = 0.35), hemoglobin level (p = 0.52), body mass index (p = 0.27), or total endoscopy time (p = 0.72) was not related to the degree of oxygen desaturation. These results suggest that oxygen desaturation is frequently observed during non-sedated diagnostic upper gastrointestinal endoscopy although severe oxygen desaturation, which may induce rare but serious cardiopulmonary events, is not common. Furthermore, we cannot predict in which patients desaturation will occur. We therefore recommend continuous monitoring of arterial oxygenation in all patients during the procedure.     

Wide gamut LCD using locally dimmable four‐primary‐color LED backlight

This paper proposes a wide gamut LCD using locally dimmable four‐primary‐color (4PC) LED backlight. Although the color gamut of LCDs has been improved in recent years, it is insufficient to reproduce all the colors in the real world. The objective of this paper is to propose a wide gamut LCD that reproduces all the colors in the real world while keeping the cost increases to a minimum. We evaluated the color gamut reproduced by LEDs of multiple primary colors and selected cyan as the optimal color to be added to the three primary colors to reproduce all the colors in the real world. Therefore, we designed an LED backlight consisting of an additional only‐cyan LED with three‐primary‐color LEDs and developed a prototype LCD with 4PC LED backlight. Furthermore, we developed a local dimming algorithm for the 4PC LED backlight. As a result, we confirmed that the prototype LCD with the 4PC LED backlight is able to cover almost all the colors in the real world and also able to display natural images with highly saturated colors by local dimming.     

Preparation of zirconia-toughened bioactive glass-ceramics

Bioactive glass-ceramics toughened by tetragonal zirconia polycrystal (TZP) were prepared by hot-pressing mixed powders of the MgO-CaO-P₂O₅-SiO₂ glass and TZP containing 20 to 80% alumina. The bending strength and the fracture toughness of the composite materials were improved compared with those of the material without TZP. These composites showed high bending strengths (400 to 500MPa) and high fracture toughness ( 2.8MPa m^1/2). The existence of a crack deflection mechanism was observed by scanning electron microscopy. After soaking in simulated physiological solution at 100 °C, no phase transformation from tetragonal to monoclinic of TZP in the composites and no degradation in bending strength occurred.     

Surface active N-acylglutamate: I. Preparation of long chain N-acylglutamic acid

Long chain N-acylglutamic acid was prepared in a high yield by a reaction of glutamic acid with fatty acid chloride in a mixed solvent of water and a water miscible organic solvent such as acetone, methyl ethyl ketone, dioxane, tetrahydrofuran,t-butyl alcohol or cyclohexanone. In this reaction the composition of the mixed solvent influenced the yield of N-acylated glutamic acid and the best yield was obtained when the reaction was carried out in the mixed solvent comprising 30–60% v/v of the organic solvent. Long chain N-acylaspartic acid was also obtained in a high yield by the same method. As the other method to obtain N-lauroyl-D L-glutamic acid, it was examined that N-acyl-α-aminoglutarodinitrile which was obtained by a reaction of α-aminoglutarodinitrile with fatty acid chloride was hydrolyzed with an aqueous alkaline solution. The salts of long chain N-acylglutamic acid are known as the surface active agents that react mildly on the human skin.     

Rapid Quenching Technique Using Thermal-Image Furnace for Glass Preparation

A new technique combining a thermal-image furnace and a twin roller is described for quenching the melt to form glass. The technique was applied to the simple system Li₂O-SiO₂, since its fundamental parameters in the estimation of critical cooling rate are available. Glass flakes were obtained in the composition Li₄SiO₄, for which a very large critical cooling rate (∼10⁹ K·s⁻¹) was needed for glass formation.     

Calibration Curve for Quantitative Analysis of the Monoclinic-Tetragonal ZrO2 System by X-Ray Diffraction

A nonlinear calibration curve for volume fraction vs integrated intensity ratio was obtained for the monoclinic-tetragonal ZrO² system by using X-ray powder pattern-fitting and pattern-decomposition techniques. The empirical equation agrees well with the theoretical one. By using this equation, the deviation from linearity (6.8% maximum) resulting from the intensity difference of corresponding reflections of the two phases can be estimated quite accurately.     

Plasma etching durability of poly(methyl methacrylate)

The decomposition of poly(methyl methacrylate) (PMMA), as a positive resist, in CF₄/O₂ plasma etching has been studied in the thin film state in order to clarify the factors influencing the dry etching durability of resists. It becomes clear that the major PMMA decomposition in CF₄/O₂ plasma etching proceeds by the mechanism of random chain scission because very small kinetic chain lengths are estimated from the gel permeation chromatography data. The Arrhenius plots for the plasma etching rate of PMMA bend above about the glass transition temperature (T_g), where rapid increase of the etching rate and remarkable pattern deformation are observed. Activation energy of the PMMA etching rate which is changed by oxygen concentration and rf power indicates various values from 3.1 to 6.5 kcal/mol below about T_g. The result of molecular weight variation in the cross section of the film suggests that the active species permeate into the film with fairly large speed and the PMMA decomposition occurs not only at the film surface but also at deep layer of the film.     

On-chip fabrication of magnetic alginate hydrogel microfibers by multilayered pneumatic microvalves

Alginate hydrogel has widespread applications in tissue engineering, cancer therapy, wound management and drug/cell/growth factor delivery due to its biocompatibility, hydrated environment and desirable viscoelastic properties. However, the lack of controllability is still an obstacle for utilizing it in the fabrication of 3D tissue constructs and accurate targeting in mass delivery. Here, we proposed a new method for achieving magnetic alginate hydrogel microfibers by dispersing magnetic nanoparticles in alginate solution and solidifying the magnetic alginate into hydrogel fiber inside microfluidic devices. The microfluidic devices have multilayered pneumatic microvalves with hemicylindrical channels to fully stop the fluids. In the experiments, the magnetic nanoparticles and the alginate solution were mixed and formed a uniform suspension. No aggregation of magnetic nanoparticles was found, which is crucial for flow control inside microfluidic devices. By regulating the flow rates of different solutions with the microvalves inside the microfluidic device, magnetic hydrogel fibers and nonmagnetic hydrogel fibers were fabricated with controlled sizes. The proposed method for fabricating magnetic hydrogel fiber holds great potential for engineering 3D tissue constructs with complex architectures and active drug release.     

One-step formation of ethyl methyl ketone from 1-butene and water on ultrastable Y-type zeolite catalyst

Proton exchanged ultrastable Y-type zeolite with silica/alumina = 40 showed a pronounced catalytic activity for the formation of ethyl methyl ketone directly from 1-butene and water. The formation rate of ethyl methyl ketone was much higher than those on MoO₃-based catalysts in the oxidation of 1-butene by oxygen. It was suggested that the basic site necessary for the formation of ethyl ketone directly from 1-butene and water would be the pentacoordinated Al.     

Hydrophobic effects on protein/nucleic acid interaction: enhancement of substrate binding by mutating tyrosine 45 to tryptophan in ribonuclease Tl

Hydrophobic effects on binding of ribonuclease Tl to guaninebases of several ribonucleotides have been proved by mutatinga hydrophobic residue at the recognition site and by measuringthe effect on binding. Mutation of a hydrophobic surface residueto a more hydrophobic residue (Tyr45 – Trp) enhances thebinding to ribonucleotides, including mononucleotide inhibitorand product, and a synthetic substrate-analog trinudeotide aswell as the binding to dinucleotide substrates and RNA. Enhancementson binding to non-substrate ribonucleotides by the mutationhave been observed with free energy changes ranging from –2.2 to – 3 .9 kJ/mol. These changes are in good agreementwith that of substrate binding, –2.3 kJ/mol, which iscalculated from Michaelis constants obtained from kinetic studies.It is shown, by comparing the observed and calculated changesin binding free energy with differences in the observed transferfree energy changes of the amino acid side chains from organicsolvents to water, that the enhancement observed on guaninebinding comes from the difference in the hydrophobic effectsof the side chains of tyrosine and tryptophan. Furthermore,a linear relationship between nucleolytic activities and hydrophobicityof the residues (Ala, Phe, Tyr, Trp) at position 45 is observed.The mutation could not change substantially the base specificityof RNase Tl, which exhibits a prime requirement for guaninebases of substrates.