Efficient transfer of the pheromone-independent Enterococcus faecium plasmid pMG1 (Gmr) (65.1 kilobases) to Enterococcus strains during broth mating

Plasmid pMG1 (65.1 kb) was isolated from a gentamicin-resistant Enterococcus faecium clinical isolate and was found to encode gentamicin resistance. EcoRI restriction of pMG1 produced five fragments, A through E, with molecular sizes of 50.2, 11.5, 2.0, 0.7, and 0.7 kb, respectively. The clockwise order of the fragments was ACDEB. pMG1 transferred at high frequency to Enterococcus strains in broth mating. pMG1 transferred between Enterococcus faecalis strains, between E. faecium strains, and between E. faecium and E. faecalis strains at a frequency of approximately 10(-4) per donor cell after 3 h of mating. The pMG1 transfers were not induced by the exposure of the donor cell to culture filtrates of plasmid-free E. faecalis FA2-2 or an E. faecium strain. Mating aggregates were not observed by the naked eye during broth mating. Small mating aggregates of several cells in the broth matings were observed by microscopy, while no aggregates of donor cells which had been exposed to a culture filtrate of E. faecalis FA2-2 or an E. faecium strain were observed, even by microscopy. pMG1 DNA did not show any homology in Southern hybridization with that of the pheromone-responsive plasmids and broad-host-range plasmids pAMbeta1 and pIP501. These results indicate that there is another efficient transfer system in the conjugative plasmids of Enterococcus and that this system is different from the pheromone-induced transfer system of E. faecalis plasmids.     

A new heparin-bonded dense membrane lung combined with minimal systemic heparinization prolonged extracorporeal lung assist in goats

Heparin was covalently bonded to a new hollow-fiber dense membrane artificial lung and extracorporeal circuit using a silane coupling agent and polyethyleneimine. This study investigated whether prolonged, venoarterial bypass extracorporeal lung assist (V-A bypass ECLA) could be sustained in a goat by the combination of the new membrane lung and minimal systemic heparinization. We maintained ECLA with the hollow-fiber lungs (surface area, 0.8 m2) and circuits by titrating the activated clotting time (ACT) to below 150 s with minimal systemic heparinization in 5 goats. The outcome was assessed from the function of the artificial lung via macro and microscopic examinations after the experiments and the incidence of systemic complications. The 5 goats were maintained on ECLA for 6 to 27 days. The bypass flow rate, blood gases at the return and drainage sites, platelet counts, and platelet aggregation activity were well maintained. Although the hemoglobin concentration, hematocrit, and plasma protein at the start of the ECLA were significantly lower than the pre-ECLA values due to hemodilution, the values remained stable during ECLA. A cerebral infarction occurred in 1 goat. However, in the other 4 goats, no complications such as bleeding, thrombosis, or plasma leakage from the artificial lung were observed. Although several thrombi were observed in the stagnant area of the artificial lung, these local thrombi did not cause the function of the artificial lung to deteriorate. We found that this new type of highly biocompatible, dense membrane artificial lung, when combined with minimal systemic heparinization, prolonged ECLA without the deterioration of the artificial lung function and was suitable for prolonged ECLA.     

Evaluation of long-term durability in high temperature resistant CFRP laminates under thermal fatigue loading

Thermal fatigue tests were conducted on high temperature resistant carbon fiber reinforced plastics cross-ply laminates to evaluate microscopic damage progress which affects macroscopic mechanical behavior of the laminates. Materials system used were thermoplastic polyetheretherketone based, AS4/PEEK and thermoset bismaleimide based, G40-800/5260. Several types of laminate configuration were used to clarify the effect of ply thickness on microscopic damage progress. Microscopic damages were observed using optical microscopy and soft X-ray radiography. Energy release rate associated with transverse cracking was calculated using variational analysis. The modified Paris law was used to predict transverse cracking. From comparison to mechanical fatigue test results, it is clarified that transverse crack accumulation rate was larger under thermal fatigue loading at same energy release rate range due to the dependence of the fracture toughness on temperature.     

Advances in software engineering and their relations to pattern recognition and image processing

In recent years ‘software engineering’ has emerged as a discipline of programming. It includes the conceptualization, design, implementation, testing and modification of software systems. Related issues are languages, standards, distributed and parallel processing, and total programming environments. The fact that more than 80 percent of system development costs were in software rather than hardware helps one appreciate the importance of any effort to understand and enhance the software production process. Many pattern recognition projects involve fairly large software efforts. It makes sense not only for researchers to make use of the latest software tools and methologies but also to anticipate future changes.     

High precision in Raman frequency achieved using real-time calibration with a neon emission line: application to three-dimensional stress mapping observations

A three-dimensional (3D) Raman mapping system with a real-time calibration function was developed for detecting stress distributions in solid materials from subtle frequency shifts in Raman spectra. An atomic emission line of neon at 918.3 cm(-1) when excited at 514.5 nm was used as a wavenumber standard. An emission spectrum of neon and a Raman spectrum from a sample were introduced into a single polychromator using a bifurcated optical fiber. These two spectra were recorded simultaneously on a charge-coupled device (CCD) detector using double-track mode. Energy deviation induced by the fluctuation of laboratory temperature, etc., was removed effectively using the neon emission line. High stability during long measurements was achieved. By applying curve fitting, positions of the Raman line were determined with precision of about 0.05 cm(-1). The present system was applied to measurements of residual pressure around mineral inclusions in a natural diamond: 3D stress mapping was achieved.     

Supersolidity and Disorder in Solid Helium 4

Supersolidity is a rather controversial issue which has been revived recently by a number of torsional oscillator (ac-rotation) experiments with solid helium 4. One possibility would be that the ground state of helium 4 crystals contains a Bose-Einstein condensate of mobile vacancies. However, the supersolid signal was shown to depend on sample history. In addition, dc-flow experiments show that superfluid transport of mass does not occur in solid helium, except if it contains appropriate grain boundaries. As a consequence, we believe that supersolidity is not an intrinsic property of helium single crystals, but that it is due to quenched disorder. We report experiments on pressure relaxation in and light scattering from solid samples, that give additional evidence for the existence of disorder in helium crystals. We also describe our recent study of the wetting properties of grain boundaries.