Mechanisms for the development of quinolone resistance

New fluoroquinolones have potent and broad antimicrobial activity and spectra, respectively, against gram-positive and -negative bacteria including P. aeruginosa. As a result of their frequent use, bacterial resistance to the quinolones has gradually developed and limited their therapeutic efficacy in infections, especially, with P. aeruginosa, S. pneumoniae, S. aureus (especially MRSA), and N. gonorrhoeae. Bacterial resistance to the quinolones probably results from : 1) mutations with chromosomal genes of DNA gyrase or DNA topoisomerase in E. coli and S. aureus, 2) decreased permeability of the cell envelope through OmpF, porin-forming protein, in gram-negative bacteria, and 3) activation of active efflux-mediated permeability through the cell membrane protein, either NorA in S. aureus or Opr in P. aeruginosa. Proper use of the quinolones is also proposed to prevent emergence of the bacterial resistance.     

Antiphospholipid syndrome complicated by thrombosis of the superior mesenteric artery, co-existence of smooth muscle hyperplasia

A 37-year-old woman underwent an emergency operation at our hospital because of severe abdominal pain and ileus. Most of her small intestine and ascending colon were observed to have become necrotic due to occlusion of her superior mesenteric artery (SMA). Pathological findings of the resected intestine revealed that her SMA was completely thrombosed 2 cm distal from its origin with smooth muscle proliferation. Post-surgical blood analysis of her pre-operative serum was positive for lupus anticoagulant and antinuclear antibodies. She noticed vaginal bleeding due to missed abortion on the 31st day after the operation. We diagnosed her acute abdominal pain to be that of antiphospholipid syndrome associated with her pregnancy.     

N-channel MOSFETs fabricated on homoepitaxy-grown 3C-SiC films

We present results of the enhancement mode, n-channel 3C-silicon carbide (SiC) MOSFETs fabricated on homoepitaxy 3C-SiC films. The fabricated devices exhibit excellent gate-controlled linear and saturation regimes of operation. The average effective channel mobility is found to be 229 cm/sup 2//Vs. The breakdown field of the gate oxide is observed at be 11 MV/cm and the subthreshold swing is determined to be 280 mV/decade.     

The stability of the CuInSe2 solar mini-module I–V characteristics under continuous and light/dark irradiation cycle tests

The stability of a CIS solar mini-module during a light/dark cycle and continuous light irradiation was investigated. Under both test conditions, the maximum power was improved during the early stages, then subsequently deteriorated. The major factors causing this phenomenon were changes in the fill-factor and open circuit voltage. The details of some parameters relevant to these factors are considered herein. In addition, the dependencies of light intensity and temperature in terms of the I–V characteristics were measured.     

Reduction in higher order effects on logic functions of asymmetricnonlinear optical fiber couplers by bandwidth limited amplification

Higher order effects such as third-order dispersion, shock effect, and soliton self-frequency shift on all-optical logic gates that use asymmetric nonlinear optical fiber couplers are investigated with the beam propagation method, and it is found that third-order dispersion seriously affects the operations of logic devices. In contrast to the case of nonvanishing third-order dispersion, the radiation is stimulated, and consequently the operations of the logic devices are degraded. In order to diminish the degradation, the bandwidth limited amplification is introduced. The logic functions can be improved by trapping only the soliton components in the finite gain-bandwidth     

Morphology-Properties relationship of a ternary polymer alloy

A ternary alloy of polyamide-6 (PA), poly(phenyleneether) (PPE), and rubber has a three-phase structure, in which PPE particles with rubber inclusions are dispersed in a PA matrix. This is an excellent thermoplastic with high impact strength and high heat resistance. To understand the morphology-properties relationship, we undertook a two-dimensional finite element method (FEM) analysis on the deformation mechanism of the ternary alloy. A three-phase model was constructed so that five hybrid particles of PPE-shell and rubber-core were embedded in the PA matrix. When the model was deformed at room temperature, the rubber domain induced yielding of the PPE-shell and the PA-matrix and at large strains the yielded zone expanded to pervade the whole space. This suggests that the toughening mechanism is essentially the same as in the binary alloy of PA and rubber (rubber-toughened PA). At higher temperatures (e.g., at 100°C) the stress concentration occurred not only in the PA matrix but also in the PPE-shell. It implies that the PPE-shell is highly responsible for bulk deformation, even though it is part of the dispersed phase. At high temperatures, the rigidity of PPE affects the alloy bulk rigidity so that the ternary system exhibits high heat resistance.     

Crystallization of nylon 6–clay hybrid by annealing under elevated pressure

Nylon 6–clay hybrid (NCH) is a molecular composite of nylon 6 and uniformly dispersed silicate layers of montmorillonite. We found that the phase with the high melting temperature (HMT phase) in the NCH annealed under elevated pressure. The melting temperature of the HMT phase was 240°C. Nylon 6 annealed under elevated pressure did not have the HMT phase. Thus, the presence of the HMT phase was characteristic of the NCH. The relative heat of fusion of the HMT phase (heat of fusion of HMT phase/heat of fusion in the pressure annealed NCH) increased with increase in pressure. High-pressure differential thermal analysis (DTA) measurement revealed that the temperature, at which the relative heat of fusion showed a maximum value, was below about 20°C of the melting temperature of the original NCH under elevated presssure. It was considered that the nylon 6 crystallite near the melting temperature and the molecular mobility under elevated pressure were necessary to the appearance to the HMT phase. © 1994 John Wiley & Sons, Inc.     

Common clonal origin of lymphocytes and plasma cells in splenic lymphoma with villous lymphocytes

In two-thirds of patients with splenic lymphoma with villous lymphocytes (SLVL) a small amount of M-protein can be detected in association with the presence of plasma cells in the peripheral blood (PB) and/or bone marrow (BM). However, it is not known whether lymphoma cells and plasma cells originate from the same clone. In this report we describe a case of SLVL which was characterized by the presence of marked monoclonal gammopathy (IgG-kappa 90 g/l) and increased plasma cells in the BM. In an attempt to elucidate the origin of lymphoma cells and plasma cells, we performed morphological, cytogenetic and molecular studies on PB mononuclear cells (PBMNC) without plasma cells and BMMNC containing 10% plasma cells from this patient. Immunofluorescence showed that lymphoma cells and plasma cells were positive for cytoplasmic gamma heavy and kappa light chains. Well-developed endoplasmic reticulum was observed in the cytoplasmic organelles of PBMNC using an electron microscope. The mean IgG concentration in the 3 d supernatant cultures of PBMNC was 374 +/- 24 microg/l. More than 50% PBMNC differentiated into plasmacytoid cells in 6 d of liquid culture with IL-3 and IL-6. Analysis by two-colour FISH revealed that karyotypic abnormalities of monosomy X and trisomy 17 existed simultaneously in both lymphoma cells and plasma cells. JH gene rearranged bands from PBMNC and BMMNC by Southern blot hybridization were identical, whereas DNAs from PBMNC failed to hybridize with the Cmu probe. These observations strongly suggest that lymphoma cells and plasma cells originate from the same clone, and that plasma cells, as well as lymphoma cells, which have undergone class switch recombination, could produce IgG type M-protein in this case.     

10 Gbit/s transmission over 50 km nonzero dispersion-shifted fibreusing 1.3 μm directly modulated uncooled transmitters

A 1.3 μm uncooled transmitter with wide-open eye diagrams at laser temperatures of 20, 50, and 85°C is presented. Using this transmitter, it is demonstrated that 10 Gbit/s transmission is possible over a 50 km nonzero dispersion-shifted Lucent TrueWave-RS fibre. This result is compared with transmission over a 55 km standard singlemode fibre     

Characterization of acylmono-, mono-, di-, tri- and tetraglycosylsterol and saponin in Adzuki bean (Vigna angularis) seeds

Five sterylglycosides (acylmono-, mono-, di tri- and tetraglycosylsterol) and a saponin were isolated from Adzuki beans and characterized. In the glycosylsterols, the principal component sterols were sitosterol and stigmasterol; the major sugar component was glucose. The glucose units were shown to be linked by β1,6-bonds. The three oligoglycosylsterols were shown to be gentiobiosylsterol, gentiotriosylsterol and gentiotetraosylsterol; the latter two are novel sterylglycosides. The saponin was identified as glucopyranosyl-(β1→2)-glucopyranurosyl-(β1→3′)-soyasapogenol B (Azukisaponin I) which had previously been found in Adzuki beans.