Alterations in the GyrA subunit of DNA gyrase and the ParC subunit of DNA topoisomerase IV associated with quinolone resistance in Enterococcus faecalis

The gyrA and parC genes of 31 clinical isolates of Enterococcus faecalis, including fluoroquinolone-resistant isolates, were partially sequenced and analyzed for target alterations. Topoisomerase IV may be a primary target in E. faecalis, but high-level fluoroquinolone resistance was associated with simultaneous alterations in both GyrA and ParC.     

An ultralow power CMOS/SIMOX programmable counter LSI

We designed and fabricated an extremely low-power CMOS/SIMOX programmable counter large scale integrated circuits (LSI) for high-speed phase-locked loop (PLL) frequency synthesizer applications. This was to verify the potential usefulness of ultrathin-film 0.24-μm-gate CMOS/SIMOX process technology for creating an extremely low-power LSI containing high-speed circuits operating at frequencies of at least 1 GHz and at low supply voltages. While operating at up to 2.2 GHz and consuming only 4.5 mW at 1.5 V, it is capable of 4-GHz performance with power consumption of 19 mW at 2.5 V. Even at a low supply voltage of 1.5 V, high input-sensitivity was also achieved in the 1- to 2-GHz frequency range. These low-power and high input-sensitivity characteristics outperform those of state-of-the-art BiCMOS PLL LSIs     

VCM design with round coil and axe-shaped magnet for hard disk drive actuator

In this paper, we proposed a novel single-sided magnet voice coil motor (VCM) design that can reduce out-of-plane force. Out-of-plane force of a VCM causes the actuator vibration, which results in settling vibration and acoustic noise. The proposed single-sided magnet VCM consists of a round coil and an axe-shaped magnet. We designed the optimized configuration by using numerical magnetic field simulation and compared its performance with those of a conventional VCM. Torsional moment was reduced by 90% at the worst position of the middle track, and bending moment was reduced by 50% at the worst position of the inner track compared with a conventional VCM. Rotational moment in our VCM was almost the same as that of the conventional one. We manufactured an actuator with the new design VCM and confirmed that the new single-sided magnet VCM shows a good performance as expected, although its magnet volume and coil resistance were almost the same as a conventional design. The measured frequency response of the actuators from the coil current to the head displacement showed that the coil torsional mode vibration of the proposed VCM is reduced remarkably.     

Creep behaviour in unloading process of cellulose nitrate under superimposed tensile and hydrostatic loading

The creep behaviour in unloading process under various combinations of superimposed tensile and hydrostatic loading are quantitatively investigated using non-linear-viscoelastic cellulose nitrate heated at 65° C. The creep strain and the creep strain-rate in the unloading process are quite influenced by the effect of hydrostatic pressure, but are not so influenced as those in the loading process mentioned in a previous paper. The deformation properties in the unloading process are also discussed with experiments for proportional loading (namely, uniform rate of stress increases or decreases with time). The stress-strain relation in the unloading process of the creep behaviour under superimposed loading is deduced by using the invariant theory. The deduced relation gives good agreement with the actual observations under the superimposed loading.     

Assignment and quantification of 2-aminopyridine derivatized oligosaccharide isomers coeluted on reversed-phase HPLC/MS by MSn spectral library

2-Aminopyridine (PA)-derivatized oligosaccharides from IgG were analyzed by using reversed-phase HPLC/mass spectrometry (RP-HPLC/MS) and a MS(n) spectral library, in particular, focusing on two pairs of isomers incompletely separated or coeluted in chromatograms. We previously reported that MS(n) spectral matching considering both major fragment ions (m/z) and intensities is useful and applicable to the structural assignment of PA-oligosaccharide isomers. In this study, MS(n) spectral matching based on the MS(n) spectral library was applied to the assignment of these PA-oligosaccharide isomers in IgG. Its usefulness was investigated by comparing it to the conventional two-dimensional mapping method based on retention time indexes. Specifically, we focus on the assignment and quantification of the isomers, which are coeluted in chromatograms. From this, we propose a new method using MS(n) spectral matching and the working curve on which are plotted the relative intensities of selected fragment ions in their MS(2) spectra versus various mixtures of the isomers. This new method demonstrated that the obtained quantities coincide very well with those estimated after separating by a combination of lectin and reversed-phase columns. This means that separation by RP-HPLC/MS is greatly simplified because complete separation of the isomers is no longer required. Application of this new method was tested by using the two other pairs of fucosylated and nonfucosylated PA-oligosaccharides from IgG. The results showed that this method works for them as well.     

Magnetic and magnetoelectric properties of self-assembled Fe₂.₅Mn₀.₅O₄ nanocrystals

We report magnetoresistance of -40%, corresponding to 80% spin polarization, at magnetic field of 0.5 T and 200 K for oleic acid-coated Fe(2.5)Mn(0.5)O(4) nanocrystals (FMO NCs) self-assembled on a SiO(2)/Si substrate by drop casting fabrication. The FMO NCs exhibited spin glass transition around 150 K and nonlinear current-voltage (I-V) characteristics. Fowler-Nordheim plot of the I-V characteristics indicated that electrons tunnel directly barriers between the FMO NCs. Transmission electron microscopy revealed that the FMO NCs are elongated hexagon in shape with size of ～15 × 20 nm. The FMO NCs self-assembled in two-dimension hexagonal networks of collinear ferromagnetic moments. The [111] easy magnetization axis of each FMO NC was parallel to each other in the hexagonal arrays. Geometrically frustrated lattice of collinear ferromagnetic moments supports both a low and a high intergranular tunneling conductance for the self-assembled FMO NCs without and with magnetic fields, respectively.     

Electrochemical oxidation for low concentration of aniline in neutral pH medium: application to the removal of aniline based on the electrochemical polymerization on a carbon fiber

Aniline, which causes serious environmental problems, was electrochemically treated and thereby removed from aqueous solution. This method demonstrated herein is based on the formation of polyaniline at an electrode surface by electrochemical oxidation. Initially, the electrode behavior of aniline at several conditions was investigated on a platinum, glassy carbon (GC), and carbon fiber (CF) electrode using voltammetric techniques. On the platinum electrode, aniline did not polymerize at low concentrations. However, electropolymerization of aniline was observed on both the GC and CF electrodes even at low concentrations in neutral pH solutions. The removal of aniline was carried out using a CF bundle with a large surface area. High removal efficiency for aniline was obtained by applying potentials greater than 0.8 V. Although generation of p-benzoquinone as a byproduct was observed during electrochemical treatment, its generation was suppressed by applying a potential lower than 0.9 V. The cyclic voltammograms and X-ray photoelectron spectra of the CF after the treatment for aniline solution showed that polymeric aniline existed on the CF surface. The maximum surface coverage of electropolymerized aniline was estimated to be about 1.49 x 10(-8) mol/cm2. Furthermore, the continuous treatment of aniline was demonstrated using a flow system.     

Hybrid White Light Emitting Diode Based on Silicon Nanocrystals

A novel design of white light emitting diodes (WLEDs) emerges to meet the growing global demand for resource sustainability while preserving health and environment. To achieve this goal, a facile method is developed for the chemical synthesis of a luminescent silicon nanocrystal (ncSi) with a large Stokes shift between absorption and emission. The WLED is prepared by a simple spin‐coating method, and contains a hybrid‐bilayer of the ncSi and luminescent polymer in its device active region. Interestingly, a well‐controlled ultrathin ncSi layer on the polymer makes possible to recombine electrons and holes in both layers, respectively. Combining red and blue‐green lights, emitted from the ncSi and the polymer layers, respectively, produces the emission of white electroluminescence. Herein, a hybrid‐WLED with a sufficiently low turn‐on voltage (3.5 V), produced by taking advantages of the large Stokes shift inherent in ncSi, is demonstrated.     

Rescue jack system applying hydrogen-absorbing alloys as a pressure source

This paper presents a flexible and compact rescue jack system that uses a hydrogen-absorbing alloy as its pressure source. The jack system comprises a container for the hydrogen-absorbing alloy and an end effector thin enough to be applied within a 2 mm-thick gap, made of a fiber-reinforced rubber bag. The hydrogen-absorbing alloy (LaNi_4.45Co_0.5Mn_0.05), whose plateau pressure was set to near atmospheric pressure at 25 °C, released hydrogen gas when heated to 50 °C. Experiments showed the system could lift 100 kg at moderate speed when the alloy container was placed in hot water (50 °C). Moreover, the jack system could maintain a 50 mm lift of 100 kg for nearly 12 h—performance comparable with that of an air jack. This clearly indicates the fiber-reinforced rubber bag is a suitable end effector of the actuator. The proposed jack system has good potential for prompt rescue activities conducted by non-professional operatives.