Changes in nuclear DNA and RNA during epidermal keratinization

The distribution of nucleic acids within nuclei of epidermal cells in skin from guinea-pig ear was investigated using an indirect enzyme digestion technique to observe both DNA and RNA, and a direct Schiff-Thallium reaction technique, to observe DNA alone. Similar results were obtained by both methods. The distribution of DNA and RNA change gradually in nuclei as epidermal cells differentiate. DNA in cells of the lower strata is localized in essentially the same areas in which electron-opaque components are seen by conventional electron microscopy. With the cytochemical treatments, however, we found that DNA is not present in all electron-opaque areas of nuclei in superficial granular cells. RNA is present in the nucleoli of cells in all layers, but its density is also lower in the upper granular cells. We postulate that nucleic acids in nuclei of granular cells gradually decrease and that the space is filled with newly synthesized electron-dense protein, as part of the differentiation process.     

Pseudo-dynamic buckling experiments on thin cylindrical shells under biaxial seismic loads

A buckling design research program has been carried out to establish seismic design guidelines for a fast breeder reactor. In doing so, the buckling strength of the cylindrical part of the reactor vessel of a fast breeder reactor under horizontal and vertical seismic loads has been clarified. The effects of axial loads on the horizontal seismic responses in pre- and post-buckling states of thin cylindrical shells are investigated. Pseudo-dynamic buckling experiments are performed to study the dynamic buckling characteristics of thin cylindrical structures when subjected to seismic loads. The buckling tests use model cylinders made of an aluminum plate and a biaxial loading test apparatus. The axial seismic loads reduce the lateral load-carrying capacity of the shells in the pre- and post-buckling regions so that they amplify the horizontal response displacement. An amplification factor that accounts for the effects of the vertical loads is presented and its validity is verified experimentally.     

Automatic parameter learning method for agent activation spreading network by evolutionary computation

Artificial Life and Robotics - A variety of planning research is being actively conducted in multiple research fields. The focus of these studies is to flexibly utilize both immediate and...     

Application of metal hydride sheet to thermally driven cooling system

This paper describes an application of a metal hydride (MH) sheet, which consists of MH powder, carbon fiber, and aramid pulp, in a metal hydride heat pump (MHHP) system with a TiFe_0.9Ni_0.1/La_0.6Y_0.4Ni_4.9Al_0.1 working pair (MH1/MH2). In the experiments, the effect of the use of MH sheet on the system performances was investigated, in which the MH sheets were used to replace part of the MH powder to improve the heat exchange performance. The sheets and powder were packed alternately into the MH beds in layers with an aspect ratio less than one. The MH sheet significantly accelerated the heat exchange ratio of both MH packed beds. Using the MH sheet in both reactors, the specific cooling power increased by 1.2 times. The results also indicated that the role of heat exchange in an MH2 reactor as a cooling output side was more important in the enhancement of system performance than that in an MH1 reactor as a heat source side. In addition, the proposed MH sheet was effective not only for improving the system performance but also for decreasing the stress on the reactor vessel due to the expansion of MH during the hydrogen absorption/desorption.     

Combustion synthesis of TiFe-based hydrogen storage alloy from titanium oxide and iron

In this paper, we describe the combustion synthesis of a TiFe-based hydrogen storage alloy from Fe and TiO₂ using metallic calcium as the reducing agent and heat source. The effects of hydrogen on the combustion ignition temperature and the hydrogenation properties of the products were examined. In the experiments, Fe, TiO₂, and Ca were mixed with a molar ratio of 1:1:4 and heated in a hydrogen atmosphere until the ignition due to the hydrogenation of calcium. For comparison, the same experiment was performed in an argon atmosphere. The ignition and maximum temperatures in the hydrogen atmosphere were drastically lower than those in the argon atmosphere. According to X-ray diffraction (XRD) analyses, all the peaks of the product combustion-synthesized in a hydrogen atmosphere were due to the TiFe phase, although some peaks of the product synthesized in argon indicated the existence of the TiO phase in addition to the TiFe phase. The product synthesized in hydrogen demonstrated a hydrogen storage capacity of 1.39 mass%, which is equal to that achieved using pure TiFe reagent. Moreover, a fine powdered product was obtained without any pulverization processes. This method creates an innovative production route for TiFe.     

Silicon-based oxynitride and nitride phosphors for white LEDs—A review

As a novel class of inorganic phosphors, oxynitride and nitride luminescent materials have received considerable attention because of their potential applications in solid-state lightings and displays. In this review we focus on recent developments in the preparation, crystal structure, luminescence and applications of silicon-based oxynitride and nitride phosphors for white light-emitting diodes (LEDs). The structures of silicon-based oxynitrides and nitrides (i.e., nitridosilicates, nitridoaluminosilicates, oxonitridosilicates, oxonitridoaluminosilicates, and sialons) are generally built up of networks of crosslinking SiN₄ tetrahedra. This is anticipated to significantly lower the excited state of the 5d electrons of doped rare-earth elements due to large crystal-field splitting and a strong nephelauxetic effect. This enables the silicon-based oxynitride and nitride phosphors to have a broad excitation band extending from the ultraviolet to visible-light range, and thus strongly absorb blue-to-green light. The structural versatility of oxynitride and nitride phosphors makes it possible to attain all the emission colors of blue, green, yellow, and red; thus, they are suitable for use in white LEDs. This novel class of phosphors has demonstrated its superior suitability for use in white LEDs and can be used in bichromatic or multichromatic LEDs with excellent properties of high luminous efficacy, high chromatic stability, a wide range of white light with adjustable correlated color temperatures (CCTs), and brilliant color-rendering properties.     

Fluorescence lifetime standards for time and frequency domain fluorescence spectroscopy

A series of fluorophores with single-exponential fluorescence decays in liquid solution at 20 degrees C were measured independently by nine laboratories using single-photon timing and multifrequency phase and modulation fluorometry instruments with lasers as excitation source. The dyes that can serve as fluorescence lifetime standards for time-domain and frequency-domain measurements are all commercially available, are photostable under the conditions of the measurements, and are soluble in solvents of spectroscopic quality (methanol, cyclohexane, water). These lifetime standards are anthracene, 9-cyanoanthracene, 9,10-diphenylanthracene, N-methylcarbazole, coumarin 153, erythrosin B, N-acetyl-l-tryptophanamide, 1,4-bis(5-phenyloxazol-2-yl)benzene, 2,5-diphenyloxazole, rhodamine B, rubrene, N-(3-sulfopropyl)acridinium, and 1,4-diphenylbenzene. At 20 degrees C, the fluorescence lifetimes vary from 89 ps to 31.2 ns, depending on fluorescent dye and solvent, which is a useful range for modern pico- and nanosecond time-domain or mega- to gigahertz frequency-domain instrumentation. The decay times are independent of the excitation and emission wavelengths. Dependent on the structure of the dye and the solvent, the excitation wavelengths used range from 284 to 575 nm, the emission from 330 to 630 nm. These lifetime standards may be used to either calibrate or test the resolution of time- and frequency-domain instrumentation or as reference compounds to eliminate the color effect in photomultiplier tubes. Statistical analyses by means of two-sample charts indicate that there is no laboratory bias in the lifetime determinations. Moreover, statistical tests show that there is an excellent correlation between the lifetimes estimated by the time-domain and frequency-domain fluorometries. Comprehensive tables compiling the results for 20 (fluorescence lifetime standard/solvent) combinations are given.     

Anomalous microstructure formed at the interface between copper ribbon and tin-deposited copper plate by ultrasonic bonding

The present paper reports an anomalous microstructure formed at interfaces between Cu ribbons and Sn-deposited Cu plates by ultrasonic bonding. The interface consists of Cu-to-Cu directly bonded part and Sn-dispersed part. In the latter part, Sn is dispersed in the vicinity of the bond interfaces being retained as Sn. The formation process of the interfacial microstructure is discussed on the basis of detailed experimental analysis and theoretical analysis on the solid-state reaction at Cu/Sn interface. The theoretical analysis reveals three important points of the reaction. (1) The formation of Cu₆Sn₅ precedes that of Cu₃Sn. (2) The incubation time for the formation of Cu₆Sn₅ changes discontinuously at the η/η′ transition temperature. (3) The incubation time for the formation of η′Cu₆Sn₅ is longer than that for ηCu₆Sn₅.     

Highly sensitive MALDI analyses of glycans by a new aminoquinoline-labeling method using 3-aminoquinoline/α-cyano-4-hydroxycinnamic acid liquid matrix

In glycomics, mass spectrometry is an indispensable tool for high throughput analyses. Generally speaking, glycans contain many hydroxyl groups and are more difficult to ionize than peptides. Derivatization of glycans has been useful for increasing sensitivity. However, it takes time to purify and causes loss of sample. Here, we show a highly sensitive aminoquinoline (AQ)-labeling method of glycans on a matrix-assisted laser desorption/ionization (MALDI) target using a liquid matrix 3-aminoquinoline (3-AQ)/α-cyano-4-hydroxycinnamic acid (CHCA). It is a rapid procedure and reduces loss of sample material during the reaction process, especially in negative ion mode where 10 amol of monosialylated N-glycan were detected as AQ-labeled molecular ions. In addition, MS/MS of 10 amol of monosialylated N-glycan was achieved.