Quantitative Elemental Analysis of a Single Cell by Using Inductively Coupled Plasma-Mass Spectrometry in Fast Time-Resolved Analysis Mode

The elemental composition of a single yeast, green alga, or red blood cell (RBC) was precisely determined by using inductively coupled plasma-mass spectrometry (ICP-MS) operating in fast time-resolved analysis (TRA) mode. The technique is known as single-cell (SC)-ICP-MS. Phosphorus, sulfur, magnesium, zinc, and iron were detected in the three types of cell. The elemental composition of yeast and green alga obtained by SC-ICP-MS was consistent with results obtained from conventional ICP-MS measurements following acid digestion of the cells. Slight differences were found in the measured values between SC-ICP-MS and the conventional ICP-MS results for RBC. However, the SC-ICP-MS results for S and Fe in RBC were closer to the estimated values for these elements that were calculated from the level of hemoglobin in RBCs. The data suggest that SC-ICP-MS is suitable for the analysis of various cell types, namely, fungus, plant, and animal cells.     

Simultaneous purification and site-specific modification of pyrroline-carboxy-lysine proteins

Sticky residue: Pyrroline-carboxy-lysine (Pcl) can be readily incorporated into proteins expressed in E. coli and mammalian cells by using the pyrrolysyl tRNA/tRNA synthetase pair. Pcl can be used as a single amino acid purification tag and can be site-specifically modified with functional probes during the elution process.     

Distribution of higher-order structures in injection-molded polypropylenes

Flexural test specimens were injection-molded from six homoisotactic polypropylenes with MFI = 0.49-25.1 dg/min under cylinder temperatures of 200-320°C. Distributions in the flow direction of higher-order structures such as crystallinity X_c, thickness of skin layer, a*-axis-oriented component fraction [A*], and crystalline orientation functions and distributions in the thickness direction of higher-order structures such as X_c, β-crystal contents, [A*], and crystalline orientation functions were studied. These higher-order structures are inhomogeneous in the flow and thickness directions, which strongly influences the product properties such as mechanical and thermal properties. Molecular orientation process in injection molding was theoretically analyzed from a viewpoint of growth of recoverable shear strain at the gate and its relaxation in the cavity, which could considerably well explain the variations in the flow and thickness directions of the quantities such as thickness of the skin layer and crystalline orientation functions which express the degree of molecular orientation.     

Micro-/nanostructural investigation of laser-cut surfaces of single- and polycrystalline diamonds

Micrometer- to nanometer-scale structures of the cut surfaces of single- and polycrystalline diamonds by a pulsed ultraviolet laser have been thoroughly investigated by scanning and transmission electron microscopy. Within the laser-cut grooves, the processed diamond surfaces are extensively covered with laser-modified debris which consists of complex layered units of graphite with various crystallinities. The units consist of 1) highly oriented graphite, 2) corrugated graphite, and 3) nanocrystalline graphite, which are sequentially located from the surface of the underlying diamond substrate to the center of the grooves. Detailed textural examinations revealed that the highly oriented graphite unit is a product of the initial graphitization of diamond by a solid-state diffusion process, whereas the latter two units are deposition products from the liquid and/or vapor phases of carbon in the later stage. The present study demonstrates that the laser-cutting of diamonds proceeds in a two-step process: 1) extensive graphitization of laser-scanning path and 2) subsequent sublimation of the pre-formed graphite. These processes are basically identical among the three different types of diamonds (single crystal type Ib, single crystal type IIa and nano-polycrystalline aggregate) tested in this study.     

Study on new GMA welding process with duplex current feeding

Gas metal arc welding (GMAW) under pure argon shielding gas atmosphere (pure argon-GMAW) is suitable to obtain a high-strength and high toughness welded joint. However, it is difficult that pure argon-GMA welding is applied practically welding structure because of arc instability. In order to perform stable pure argon-GMA welding, duplex current feeding GMAW (DCF-GMAW) has been developed. The DCF-GMAW consists of primary GMA welding current and secondary welding current by constant-current power resource. DFC-GMAW can feed larger current near wire tip. This effect makes that weld penetration depth is deeper, weld bead shape is improved using DCF-GMAW.     

Surface Analysis of Cr2O3‐, CoO‐, and Al2O3‐Doped Iron–Phosphate Glasses at High Temperature

Surface structures of iron–phosphate glasses were examined using X‐ray photoelectron spectroscopy (XPS). Cr₂O₃, CoO, and Al₂O₃ were introduced to the glass by the replacement of a part of Fe₂O₃, and the simulated fission products are also added. The obtained glasses showed high chemical durabilities by MCC‐1 test. In situ high‐temperature and room‐temperature XPS measurements were conducted on the polished sample surfaces and also those after 1‐week chemical durability test. Unique trends were observed in XPS spectra on heating and after the chemical durability test, respectively. Nature of the glass surface of iron–phosphate glasses was explained from the point of view of surface energy, and the origin of high chemical durability and the effect of chromium ions were discussed based on the changes on surface composition and valence states of transition‐metal ions.     

Characterization and CO2 sorption properties of poly[methacryloxypropylheptacyclopentyl‐T8‐silsesquioxane‐ co‐3‐methacryloxypropyltris(trimethylsiloxy)silane]

Poly[methacryloxypropylheptacyclopentyl‐T8‐silsesquioxane (MAPOSS)‐co‐3‐methacryloxypropyltris(trimethylsiloxy)silane (SiMA)] was synthesized through free radical polymerization. The physical and carbon dioxide (CO₂) sorption properties of the copolymer membranes were investigated in terms of the MAPOSS content. As the MAPOSS content increases, the membrane density increased, suggesting a decrease in the fractional free volume. In addition, the thermal stability was improved with increasing the MAPOSS content. These are because of the polyhedraloligomericilsesquioxane (POSS) units that restrict the high mobility of poly(SiMA) segments. The glass transition temperature, T_g of the copolymers was single T_g based on the differential scanning calorimetry, suggesting that the copolymers were random and not phase separation. Based on the CO₂ sorption measurement, the POSS units play a role in reducing Henry's dissolution by suppressing the mobility of the poly(SiMA) component, while POSS units increase the nonequilibrium excess free volume, which contributes to the Langmuir dissolution. Based on these results, the introduction of MAPOSS unit is one of the effective ways to improved the thermal stability and CO₂ sorption property due to the enhancement of the polymer rigidity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of sintering additive on crystallographic orientation in AlN prepared by slip casting in a strong magnetic field

The preparation of oriented AlN bulk ceramics with and without additives was achieved by slip casting in a high magnetic field. The a and b axes of the AlN were aligned parallel to the direction of the magnetic field. The degree of crystallographic orientation was controlled by the viscosity of the slurry and the grain growth during sintering attributed to the sintering additives. The mechanical properties of the textured AlN depended on the direction of the crystallographic orientation.     

Application of SPRT to an image data sequence for a remote monitoring system

Recently, remote monitoring camera systems have been widely used for security. In such systems, one important function is that the system automatically detects any change in the scenes from the monitoring cameras. In wireless remote monitoring camera systems, the images of the scenes are generally transmitted as compressed data (e.g., JPEG file), because of the capacity of the wireless channel. This article shows the automated detection of the change point in time-series data of compressed JPEG file quantity (Kbytes) from the monitoring camera by applying the sequential probabilistic ratio test (SPRT) and the Chow test, which is well known as a standard method for detecting structural change in time-series data.     

Novel circular-beam equalizing techniques that use graded-index fiber optics for a high-power laser diode

We demonstrate a novel method of equalizing a laser diode (LD) beam into a circular beam. This method uses the twist effect of graded index (GI) fiber optics. An asymmetric LD beam with beam qualities of M2 = 500 in the slow axis and M2 = 4 in the fast axis is converted successfully into a symmetric circular beam with a beam quality of M2 = 175. The circular-output beam with 92% coupling efficiency from the fiber input to the fiber output is obtained with a 5-m-long GI1200 (1200 means a core diameter of 1200 microm) fiber for a 2-W LD array. We extend the experiments to a higher-power source with higher asymmetric beam qualities of M2 = 3000 and M2 = 4. By slightly bending the GI10000 (10000 means a core diameter of 10,000 microm) fiber, we have succeeded in generating a symmetric beam with a improved beam quality of M2 = 2000. The average beam quality is preserved when the asymmetric ratio is not high, and the beam quality degradation ratio is investigated up to asymmetric ratios of 750.