Enterohemorrhagic Escherichia coli O157 outbreak in Obihiro-city--biological and molecular characteristics among O157 isolates]

The outbreak of enterohaemorrhagic Escherichia coli (EHEC) O157:H7 infection in Obihiro City, Japan, occurred in late October 1996. The infection affected a total of 169 kindergarten pupils and school staff members in a private kindergarten. Twenty-one children (12.4%) progressed into hemolytic uremic syndrome (HUS). Moreover, the person-to-person infections in 9 families and the duration of excretion of EHEC in 13 patients were observed. The contaminated food was identified as the potato-salad served at lunch. Analysis of biological characteristics, the ability of toxin production, and the DNA analysis by PCR-based fingerprinting, the RAPD tests, among all clinical isolates, clarified a homologous origin of contamination.     

Combustion rates of graphite rods in the forward stagnation field with high-temperature airflow

An experiment has been conducted to measure combustion rates of graphite rods in the forward stagnation field with high-temperature airflow of 1280 K, to elucidate its combustion behavior. It is found that the combustion rate in the high-temperature airflow is enhanced, because of the elevated transport property due to an increase in the airflow temperature, when the mass flow rate of air is kept constant, and that it is reduced, because of a reduced mass transfer rate of oxygen through the thickened boundary layer, due to reduced density in the gas phase, when the velocity gradient is the same. It is also confirmed that even in the high-temperature air combustion, there occurs an abrupt decrease in the combustion rate when the velocity gradient is lower than about 1000 s⁻¹, because of the establishment of the CO flame. Theoretical works have also been conducted and it is found that the combustion rate can fairly be obtained numerically, as far as the trend and the approximate magnitude are concerned. It has turned out that the combustion rate in the high-temperature oxidizer-flow has nearly the same value as that in the room-temperature airflow even when the oxygen mass fraction is reduced to be about 0.15. It is also found that the oxygen mass fraction can be reduced to be about 0.07, when there exists enough CO₂ in the oxidizer and the surface temperature is enough high, say, more than 2000 K.     

Trajectory control of controlled-PM linear synchronous motor magnetic levitation vehicle—FEM dynamics simulations and experiments in mass-reduced-control mode

A novel magnetic levitation train system can be constructed by using a long-stator controlled-PM linear synchronous motor having propulsion and attractive-mode levitation functions and minimum loss. Realizing this system requires simplifying manufacture of the long-stator guideway. In the long-stator on the ground, semiclosed large slots are adapted and designed for one-turn coils of a waveform to be easily installed. The large slots cause the PM LSM detent forces to give strong influences on dynamic operations of the running vehicle. A two-dimensional FEM used for the dynamics simulations is capable of precisely analyzing the detent forces produced between the stator teeth and the PMs. This paper presents FEM dynamics simulations and experiments in mass-reduced-control mode of a 1/2 scale model magnetic levitation vehicle supported by small rubber rollers. The simulation model developed here includes the vehicle speed performance, position sensors and drag force due to friction between rubber roller and rail. The detent force problem in propulsion motion is successfully solved by adapting the feedback control of the vehicle propulsion based on the I₁₀-controlled method. The trajectory control is thus accomplished for the vehicle to follow speed and position patterns. The dynamics simulations are verified from the experiments. The simulation program proposed here enables us to investigate the magnetic levitation train system, including LSM design and vehicle dynamic operations.     

Capillary electrophoresis for therapeutic drug monitoring of antiepileptics

We examined the use of capillary electrophoresis for therapeutic drug monitoring of antiepileptic drugs. Micellar electrokinetic capillary chromatography (MEKC) with a diode array detector simultaneously determined concentrations of zonisamide, a new type of antiepileptic drug, and phenobarbital, phenytoin and carbamazepine, typical antiepileptic drugs, in human serum. Zonisamide levels in human serum obtained by MEKC correlated well with levels obtained by high-performance liquid chromatography. The serum levels of phenobarbital, phenytoin and carbamazepine determined by MEKC were almost equal to those obtained by fluorescence polarization immunoassay. The reproducibility of separation and quantification with MEKC for intra- and inter-day assays were appropriate. This MEKC method could provide a simple and efficient therapeutic drug monitoring method for antiepileptic drugs, especially in patients treated with a combination of zonisamide and other antiepileptic drugs. MEKC may be an attractive method for therapeutic drug monitoring, because of its specificity of separation, automation of procedure, ease of method development, low cost, small aqueous buffer amounts, speed of analysis, small injection volume and high environment-directed performance.     

Analytical formulas for the optical gain of quantum wells

Analytical expressions for the quantized energy levels in quantum wells, the optical gain, the differential optical gain, and the linewidth enhancement factor are presented based on a simple parabolic-band gain model. Explicit formulas show clearly the dependence of these factors on well width, doping, and photon energy. The optical gain in the form of g=g₀ In(N/N₀) is derived using explicit approximations in the Fermi functions, where g₀ is the proportionality constant, N is the injected carrier density, and N ₀ is the transparency carrier density. The approximate formulas are shown to provide not only an efficient way of computing the gain-related parameters but also a convenient way of getting physical insights into the overall interplay of quantum well parameters     

Possible modulation by endothelin-1, nitric oxide, prostaglandin I2 and thromboxane A2 of vasoconstriction induced by an alpha-agonist in mesenteric arterial bed from diabetic rats

We hypothesized that in diabetes arterial reactivity to constrictors is attenuated by certain endothelium-derived substances. We examined the vasoconstriction induced by methoxamine (alpha1-agonist) in isolated mesenteric arterial beds from streptozotocin (STZ)-induced diabetic rats and age-matched control rats. The dose-response curve for methoxamine was shifted to the right and the maximum contractile response was impaired in mesenteric arterial beds from diabetic rats. The methoxamine vasoconstriction was reduced in endothelium-denuded preparations from controls rats, but increased in those from diabetic rats. Treatment with the nitric oxide synthase inhibitor NG-nitro-L-arginine enhanced the vasoconstrictions induced by methoxamine in both control and diabetic rats. Indomethacin had no effect on the methoxamine vasoconstriction in control rats, but it shifted the dose-response curve to the left in diabetic rats. Whether given with or without indomethacin, BQ-123, (an ET(A)-receptor antagonist) plus BQ-788 (an ET(B)-receptor antagonist) shifted the dose-response curve for methoxamine to the right in control rats (while reducing the maximum response) but to the left in diabetic rats. The methoxamine-stimulated release of 6-keto-prostaglandin F1alpha from the mesenteric arterial bed in diabetic rats was approximately four times that seen in the control rats, while the methoxamine-induced release of thromboxane B2 (TXB2), a metabolite of thromboxane A2 (TXA2), was less in diabetic rats than in the control animals. These results suggest that an increased production of prostaglandin I2 (PGI2) and decreased formation of TXA2 could be responsible for the attenuation of the methoxamine-induced mesenteric vasoconstriction seen in diabetic rats, and these changes in the diabetic state could be partly responsible for the lower blood pressure seen in our diabetic rats.     

Propentofylline inhibits production of TNFalpha and infection of LP-BM5 murine leukemia virus in glial cells

Much evidence points to the involvement of N-methyl-D-aspartate (NMDA) receptors in the development and maintainance of neuropathic pain. In neuropathic pain, there is generally involved a presumed opioid-insensitive component, which apparently can be blocked by NMDA receptor antagonists. However, in order to obtain complete analgesia, a combination of an NMDA receptor antagonist and an opioid receptor agonist is needed. Recent in vitro data have demonstrated that methadone, ketobemidone, and dextropropoxyphene, in addition to being opioid receptor agonists, also are weak noncompetitive NMDA receptor antagonists. Clinical anecdotes suggest that the NMDA receptor antagonism of these opioids may play a significant role in the pharmacological action of these compounds; however, no clinical studies have been conducted to support this issue. In the present commentary, we discuss evidence for the NMDA receptor antagonism of these compounds and its relevance for clinical pain treatment; an overview of structure-activity relationships for the relevant opioids as noncompetitive NMDA receptor antagonists also is given. It is concluded that although the finding that some opioids are weak noncompetitive NMDA receptor antagonists in vitro has created much attention among clinicians, no clinical studies have been conducted to evaluate the applicability of these compounds in the treatment of neuropathic pain conditions.     

Effective operation method by interdependent use of condenser energy of the voltage transient sag compensator with controlled gradational voltage

This paper presents the efficient operation method of the interdependent use of condenser energy on the new concept of voltage transient sag compensator. This compensator consists of the series connection inverter units, and each inverter unit generates a different output voltage by 2ⁿ times. The method proposed here, in any case of various levels of transient voltage sags on the power line, provides the efficient use of condenser energy of all these inverter units. The method of interdependent use of condenser energy is also verified by the experiment. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(3): 56–64, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20290     

Modeling and design of a DFB laser integrated with a Mach-Zehndermodulator

A comprehensive model for a complex-coupled distributed feedback laser diode monolithically integrated with a Mach-Zehnder modulator is developed and validated by comparison with experimental data. Methods and their tradeoffs for reduction of adiabatic frequency chirp due to the parasitic reflections from the modulator are discussed     

Performance of a laser disdrometer with hydrometeor imaging capabilities and fall velocity estimates for snowfall

A low‐cost laser disdrometer (LLD), which is a type of high‐speed line‐image scanner, has been developed and calibrated for raindrops. The disdrometer measures hydrometeor's particle‐size distribution (PSD) and fall velocities, as well as record hydrometeor images. Hydrometeor imaging is advantageous for hydrometeor classification. All hydrometeor types, raindrops, graupels, snowflakes, and ice crystals, can mix with snowfall. Snowfall sensing requires a wide sensing light sheet to capture large‐sized snowflakes. Accordingly, a new LLD equipped with a 35‐mm sensing light sheet has been developed. This paper demonstrates and evaluates the new drisdrometer's snowfall‐evaluation performance. The wide sensing light sheet captures images of large‐sized (14 mm) snowflakes reasonably well, and the PSD and the fall velocities correlate with those measured with the commercially available Parsivel laser disdrometer. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.