Influence of PEG-borate ester on thermal property and ionic conductivity of the polymer electrolyte

We have focused on the poly(ethylene glycol) (PEG)-borate ester as a new type plasticizer for solid polymer electrolyte for lithium ion secondary battery. Adding the PEG-borate ester into the electrolyte shows the increase in the ionic conductivity of the polymer electrolyte. By measuring the glass-transition temperature of the polymer electrolytes with DSC, it is found that the increase in ionic conductivity of the polymer electrolyte is due to the increase in ionic mobility. By investigating the temperature dependence of the ionic conductivity of the polymer electrolytes using William-Landel-Ferry type equation, we considered that the PEG-borate ester does not have any influence for dissociation of Li-salt. This revised version was published online in August 2006 with corrections to the Cover Date.     

Determination of beta-lactam antibiotics in water by fluorescence quenching of mercurochrome, and application for simple investigation of potency

The fluorescence quenching reaction between fluorescein mercury or halogeno-fluorescein mercury compounds (fl. Hg, 2,7- or 2,4-dichloro-fl.Hg, 3',4',5',6'-tetrachloro-fl.Hg, mercurochrome) and beta-lactam antibiotics (ampicillin (AB-PC) and cephalexin (CEX] was investigated, and mercurochrome was selected for the detection of beta-lactam antibiotics; the detection limit was about 0.8 micrograms/ml. A fluorimetric assay of beta-lactam antibiotics was established by measuring the fluorescence of mercurochrome and mercurochrome-beta-lactam antibiotics solutions in weakly basic media to determine the degree of fluorescence quenching. The maximum emission wavelength of mercurochrome solution was at 544 nm with excitation at 470 nm. The calibration graphs were linear over the ranges of about 0-6 micrograms/ml beta-lactam antibiotics penicillins (AB-PC, penicillin G, sulbenicillin, amoxicillin, cyclacillin, oxacillin, hetacillin and piperacillin) and cepham antibiotics (CEX, cefazolin, cephaloglycin, cephaloridine and cefpyramide), and the relative standard deviation was 2.7% for 1.4 micrograms/ml of AB-PC (n = 5). This fluorescence quenching reaction between mercurochrome and beta-lactam antibiotics was applied in a survey of decomposition and remaining potency of beta-lactam antibiotics.     

Structural disorder along the lithium diffusion pathway in cubically stabilized lithium manganese spinel: I. Synchrotron X-ray studies

Electron density distribution, EXAFS, and transmission electron microscope studies on stoichiometric Li(Mg_1/6Mn_11/6)O₄ have revealed that: (1) the structure is essentially of spinel-type with slight diffuse scattering, (2) the Li atoms are not all located at the ideal 8a site of the spinel structure, but are partially tetrahedrally distributed along the 8a-16c tie line, (3) the O atoms also exhibit a statistical distribution about their ideal positions and (4) the Mn 3d electrons are squeezed out toward the open space of the coordinating octahedra with D_3d distortion. The present results indicate the possible existence of many metastable Li positions in the structure, suggestive of complicated Li atom hopping routes in conjunction with a local distortion of neighboring atoms at least up to the second shell.     

Two new steroidal derivatives from the fruit body of Chlorophyllum molybdites

Two new steroid derivatives, (22E,24R)-3alpha-ureido-ergosta-4,6,8(14),22-tetraene (1) and (22E,24R)-5alpha,8alpha-epidioxyergosta-6,9,22-triene-3beta-ol 3-O-beta-D-glucopyranoside (2) were isolated from the fruit bodies of Chlorophyllum molybdites (Agaricaceae). The structures were established by spectroscopic and chemical methods. These compounds exhibited cytotoxicity against Kato III cells.     

Improvement of substrate conversion to molecular hydrogen by three-stage cultivation of a photosynthetic bacterium,Rhodovulum sulfidophilum

In photosynthetic bacteria, after transition to light-anaerobic and nitrogen-deficient conditions, hydrogen evolution starts with expression of nitrogenase activity. Until the expression of enough activity,Rhodovulum sulfidophilum consumed substrates and converted them to poly(3-hydrox-ybutyrate) (PHB), resulting in a decrease in the proportion of substrate converted into hydrogen gas. To prevent conversion to PHB during the period when nitrogenase activity is derepressed, the authors employed a cultivation method consisting of three stages: cell growth, nitrogenase derepression, and hydrogen production. Cells cultivated by this method exhibited no lag time before the commencement of hydrogen evolution and gave an improved yield of hydrogen from the algal fermentative products.     

Microreactor utilizing a vertically-aligned carbon nanotube array grown inside the channels

We have fabricated a microreactor incorporating vertically-aligned carbon nanotubes supporting Pt nanoparticles and found that the presence of aligned nanotubes significantly enhances the catalytic reaction and extends the catalyst lifetime as compared with conventional microreactors using a Pt metal film or Pt nanoparticles directly deposited on the channel walls.     

Oxidation of 4-Oxo-4H-1-Benzopyran-3-Carboxaldehydes with N-Bromosuccinimide

4-Oxo-4-H-1-benzopyran-3-carboxylic acids and their derivatives (esters and amides), 2, are known to possess interesting pharmacological activities.¹ As part of our synthetic studies of biologically active compounds, we needed to prepare a variety of 2 (carboxylic acids, esters, amides, etc.). An elegant method for the preparation of 4-oxo-4H-1-benzopyran-3-carboxaldehydes, 1, was reported independently by Nohara et al. ² and Harnish.³ However, despite a rather extensive effort by Nohara et al., the oxidation of 1 to 2 (Y=OH) has not been realized in good yield; thus the yields by Jones oxidation, the best reported method, ranged only from 9.5 to 39%.⁴     

Hydrophilic Domains Enhance Nanobubble Stability

Highly stable nanoscale gas states at solid/liquid interfaces, referred to as nanobubbles, have been widely studied for over a decade. In this study, nanobubbles generated on a hydrophobic Teflon amorphous fluoroplastic thin film in the presence and absence of hydrophilic carbon domains are investigated by peak force quantitative nanomechanics. On the hydrophobic surface without hydrophilic domains, a small number of nanobubbles are generated and then rapidly decrease in size. On the hydrophobic surface with hydrophilic domains, the hydrophilic domains have a significant effect on the generation and stability of nanobubbles, with bubbles remaining on the surface for up to three days.     

Observation of optomechanical coupling in a microbottle resonator

In this work, we report optomechanical coupling, resolved sidebands and phonon lasing in a solid‐core microbottle resonator fabricated on a single mode optical fiber. Mechanical modes with quality factors (Q_m) as high as 1.57 × 10⁴ and 1.45 × 10⁴ were observed, respectively, at the mechanical frequencies and . The maximum  Hz is close to the theoretical lower bound of 6 × 10¹² Hz needed to overcome thermal decoherence for resolved‐sideband cooling of mechanical motion at room temperature, suggesting microbottle resonators as a possible platform for this endeavor. In addition to optomechanical effects, scatter‐induced mode splitting and ringing phenomena, which are typical for high‐quality optical resonances, were also observed in a microbottle resonator.