Adaptation study for biofilm of the urinary tract via highly complicated bladder model (biofilm model of the urinary tract)--experimental study using automatic simulator of the urinary antimicrobial agent concentration

With the view of making an adaptation study for biofilm of the urinary tract, we devised a computer-controlled highly complicated bladder model (biofilm model of the urinary tract) that allowed the simulation of time-course changes in the urinary concentration of antimicrobial agents. Clarithromycin (CAM), which is reported to have an anti-biofilm action, was examined at urinary levels approximating clinical concentrations and its effect on biofilm was determined. The following results were obtained. 1) Ofloxacin (OFLX, 200 mg x 2/day, MIC; 8 micrograms/ml), which is active against Pseudomonas aruginosa, caused apparent microbial elimination from the model at 42 hours, but bacterial regrowth occurred 4 hours after withdrawal of this agent. No disappearance of the biofilm was noted with OFLX suggesting that this was the cause of bacterial regrowth. 2) The combination of OFLX (200 mg x 2/day) and CAM (MIC; > 128 micrograms/ml, 200 mg x 2/day) on anti-biofilm agent, with no effect on P. aeruginosa, eliminated bacteria from the bladder model more rapidly and prolonged the regrowth time to 10 hours after withdrawal of the antimicrobial agents. Disappearance of most of the biofilm and only slight microbial adhesion was noted. 3) The combination of OFLX (200 mg x 2/day) and CAM (400 mg x 3/day) caused microbial elimination from the bladder model with no regrowth at 30 hours after withdrawal of the antimicrobial agents. The biofilm disappeared completely and no microbial adhesion was noted. 4) CAM alone (400 mg x 3/day) allowed microbial recovery to the initial level within 48 hours after withdrawal, but led to disappearance of the biofilm and the adhesion of microbes without a glycocalyx. 5) These results suggest that the anti-biofilm action of CAM is dose-dependent, and that combined use of an appropriate antimicrobial agent and anti-biofilm agent like CAM may be effective for biofilm infections of the urinary tract.     

The pharmacology of amino-acid responses in septal neurons

Septal cholinergic neurons are known to play an important role in cognitive processes including learning and memory through afferent innervation of the hippocampal formation and cerebral cortex. The septum contains not only cholinergic neurons but also various types of neurons including GABA (gamma-aminobutyric acid)-ergic neurons. Although synaptic transmission in the septum is mediated primarily by the activation of excitatory and inhibitory amino-acid receptors, it is possible that a distinct phenotype of neuron is endowed with a different type for each of the amino-acid receptors and thus they play different roles from each other, since it has been demonstrated within the septum that there is a regional distribution of various types of amino-acid receptor subunits, their expression as different combinations within a specific cell may produce receptor channels with disparate functional properties. As a first step towards knowing the various functions of septal cholinergic neurons, we characterized the functional properties of glutamate, GABA (type A; GABAA) and glycine receptor channels on cultured rat septal neurons which were histologically identified to be cholinergic. These were similar to those of receptor channels on other types of neurons, except for the actions of some neuromodulators. The septal N-methyl-D-aspartate receptor channel was distinct in being less sensitive to Mg2+ and in a voltage-dependent action of Zn2+. The septal GABAA receptor channel exhibited a lanthanide site whose activation resulted in a positive allosteric interaction with a binding site of pentobarbital. The septal glycine receptor channel was only positively modulated by Zn2+; this action of Zn2+ was not accompanied by an inhibitory effect. Our data suggest that the amino-acid receptors on septal cholinergic neurons may play a distinct role compared to other types of neurons; this difference depends on the actions of neuromodulators and metal cations. It would be interesting to compare these effects recorded in tissue culture to those observed with septal cholinergic neurons in slice preparations.     

Evaluating Flood Hazard for Land-Use Planning in Greater Dhaka of Bangladesh Using Remote Sensing and GIS Techniques

Floods are a common feature in rapidly urbanizing Dhaka and its adjoining areas. Though Greater Dhaka experiences flood almost in every year, flood management policies are mostly based on structural options including flood walls, dykes, embankments etc. Many shortcomings of the existing flood management systems are reported in numerous literatures. The objective of this paper is to assess flood hazard in Greater Dhaka for the historical flood event of 1998 using Synthetic Aperture Radar (SAR) data with GIS data. Flood-affected frequency and flood depth calculated from the multi-date SAR imageries were used as hydrologic parameters. Elevation heights, land cover classification, geomorphic division and drainage network data generated from optical remote sensing and analogue maps were used through GIS approach. Using a ranking matrix in three dimensional multiplication mode, flood hazard was assessed. All possible combination of flood hazard maps was prepared using land-cover, geomorphology and elevation heights for flood-affected frequency and floodwater depth. Using two hazard maps which produced the highest congruence for flood frequency and flood depth, a new flood hazard map was developed by considering the interactive effect of flood-affected frequency and floodwater depth, simultaneously. This new hazard map can provide more safety for flood countermeasures because pixels belonging to higher hazard degrees were increased due to the consideration of higher degrees of ranks. The estimation of flood hazard areas revealed that a major portion of Greater Dhaka comprised moderate to very high hazard zone. Only a little portion (8.04%) was found to be the least vulnerable to potential flood hazard. Conversely, 28.70% of Greater Dhaka was found within very high hazard zone. Based on this study, comprehensive flood hazard management strategies for land use planning decision were proposed for the efficient management of future flood disasters.     

Unveiling Two Consecutive Hydroxylations: Mechanisms of Aromatic Hydroxylations Catalyzed by Flavin-Dependent Monooxygenases for the Biosynthesis of Actinorhodin and Related Antibiotics

Flavin-dependent monooxygenases are ubiquitous in living systems and are classified into single- or two-component systems. Actinorhodin, produced by Streptomyces coelicolor, is a representative polycyclic polyketide that is hydroxylated through the action of the two-component ActVA-5/ActVB hydroxylase system. These homologous systems are widely distributed in bacteria, but their reaction mechanisms remain unclear. This in vitro investigation has provided chemical proof of two consecutive hydroxylations via hydroxynaphthalene intermediates involved in actinorhodin biosynthesis. The ActVA-5 oxygenase component catalyzed a stepwise dihydroxylation of the substrate, whereas the ActVB flavin reductase not only supplied a reduced cofactor, but also regulated the quinone–hydroquinone interconversion of an intermediate. Our study provides clues for understanding the general biosynthetic mechanisms of highly functionalized aromatic natural products with structural diversity.     

Application of sputter-deposited amorphous and anatase TiO2 as electron-collecting layers in inverted organic photovoltaics

We demonstrate the deposition of amorphous and anatase TiO₂ on indium tin oxide (ITO) substrates via the process of sputtering, and the use of these materials as electron-collecting layers (ECLs) in inverted-type organic photovoltaics (OPVs). Anatase TiO₂ was obtained via vacuum-annealing of as-deposited amorphous TiO₂ at 300 °C. No deterioration of optical and electrical properties of ITO was observed after both sputter-deposition of TiO₂ and annealing process. The anatase TiO₂ proved to be an effective ECL when employed in inverted OPVs using bulk heterojunction photoactive layer of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester, achieving a power conversion efficiency of 3.3% (J_SC = 9.0 mA cm^?2, V_OC = 0.62 V and FF = 0.60).     

Power supply systems for rapid cycling synchrotron

JAEA and KEK are jointly constructing the high‐intensity proton accelerator project J‐PARC. Its main accelerator is a 3‐GeV rapid cycling synchrotron (RCS). Two types of resonant excitation systems, parallel and cascade, are introduced to excite DC biased 25‐Hz AC currents through its main magnets. The parallel excitation is adopted for the dipole magnet power supply system, and the cascade excitations are adopted for the seven family quadrupole magnets system. In this paper, the two systems are investigated and analyzed, and an explanation is given as to why the different types are adopted in each system. The authors believe that such hybrid exciting systems are most suitable for a high‐power RCS. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 49–60, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20535     

Collaborative capturing, interpreting, and sharing of experiences

This paper proposes a notion of interaction corpus, a captured collection of human behaviors and interactions among humans and artifacts. Digital multimedia and ubiquitous sensor technologies create a venue to capture and store interactions that are automatically annotated. A very large-scale accumulated corpus provides an important infrastructure for a future digital society for both humans and computers to understand verbal/non-verbal mechanisms of human interactions. The interaction corpus can also be used as a well-structured stored experience, which is shared with other people for communication and creation of further experiences. Our approach employs wearable and ubiquitous sensors, such as video cameras, microphones, and tracking tags, to capture all of the events from multiple viewpoints simultaneously. We demonstrate an application of generating a video-based experience summary that is reconfigured automatically from the interaction corpus.

Effect of poly(vinylidene fluoride) binder crystallinity and graphite structure on the mechanical strength of the composite anode in a lithium ion battery

We have evaluated the mechanical strength of a series of composites consisting of carbon particles bound together by poly(vinylidene fluoride) (PVDF), which is closely related to the carbonaceous anode in a lithium ion battery. We used a balanced beam scrape adhesion tester and evaluated the influence of carbon particle structure, the chemical properties of PVDF, and the processing parameters of annealing temperature and casting solvent on the adhesion of the composite film to a copper substrate. The composite prepared with amorphous carbon shows over 10 times higher adhesion strength than those fabricated from other graphite materials. This results from chemical binding that is intermediate between semi-ionic and covalent C-F bonds, as detected by X-ray photoelectron spectroscopy. To address the effect of the crystalline phase of the binder on the adhesion strength, we investigated PVDF crystallinity in the composite films using differential scanning calorimetry. Samples with higher crystallinity show higher adhesion strength, independent of annealing temperature and casting solvent. The scratch adhesion was also measured for swollen electrodes immersed in 3:7 volume ratio of ethylene carbonate:ethyl methyl carbonate (EC:EMC) at different temperatures. After being swollen, the composite films prepared from PVDF modified with hydroxyl functional groups show higher adhesion strengths than the others due to their low uptake of the electrolyte solvent.     

Dagger-Sampling Monte Carlo For System Unavailability Evaluation

Reliability problems usually result in rare-event simulations, and hence direct Monte Carlo methods are extremely wasteful of computer time. This paper presents a new application of ``dagger-sampling', for calculating the system unavailability of a large complicated system represented by a coherent fault tree. Since a small number of uniform random numbers generate a number of trials, dagger-sampling appreciably reduces computation time, and hence a large number of trials become possible for the rare-event problems. Further, dagger-sampling decreases the variance of the Monte Carlo estimator because it generates negatively correlated samples.