Methyl 3‐Hydroxymyristate,a Diffusible Signal Mediating phc Quorum Sensing in Ralstonia solanacearum

Ralstonia solanacearum, a plant pathogenic bacterium causing “bacterial wilt” on crops, uses a quorum sensing (QS) system consisting of phc regulatory elements to control its virulence. Methyl 3‐hydroxypalmitate (3‐OH PAME) was previously identified as the QS signal in strain AW1. However, 3‐OH PAME has not been reportedly detected from any other strains, and this suggests that they produce another unknown QS signal. Here we identify (R)‐methyl 3‐hydroxymyristate [(R)‐3‐OH MAME] as a new QS signal that regulates the production of virulence factors and secondary metabolites. (R)‐3‐OH MAME was synthesized by the methyltransferase PhcB and sensed by the histidine kinase PhcS. The phylogenetic trees of these proteins from R. solanacearum strains were divided into two groups, according to their QS signal types—(R)‐3‐OH MAME or (R)‐3‐OH PAME. These results demonstrate that (R)‐3‐OH MAME is another crucial QS signal and highlight the unique evolution of QS systems in R. solanacearum.     

A study of robust generation mix under uncertain environments

In recent years, the trend has been toward factors (e.g., demand for load, energy cost) becoming more and more uncertain in power system expansion planning. Thus, it has become necessary to take this uncertainty into account in determining generation plans. In this paper, a robust generation plan is defined explicitly as a plan that ensures fixed performance (economy) despite deviations in these factors. In addition, a new formulation of the robust generation mix problem, whose purpose is to determine the most robust combination of plants in a target year, is proposed. It is generally difficult to solve the formulated problem with parameters. However, by analyzing a proposed formulation from the viewpoint of optimization, we show that the proposed formulation is transformed into the conventional optimization problem without parameters. The simulation results on a typical model show that the generation mix produced by the proposed formulation is more robust than that produced by the conventional formulation. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(1): 26–35, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.2009     

Permeability properties of glycol chitosan membrane modified with thiol groups

Water-soluble glycol chitosan (GC), having the ability to form a membrane, was modified with 3,3′-dithiodipropionic acid (DTPA), a functional group that causes the thiol ? disulfide transition through redox reaction. The membrane derived from this modified GC was water-insoluble. The permeabilities of KCI and socrose through the GC membrane modified with DTPA (M_DTPA), the reduced membrane (M_SH), and the oxidized membrane (M_SS) were investigated. The permeability through the M_SH membrane increased twofold relative to that through the M_DTPA membrane, and the M_SS membrane showed a 60% decrease in the permeability, which had increased in the case of the M_SH membrane. The permeability of sucrose was lower and more changeable than that of KCl. These permeation phenomena were discussed from the viewpoint that the thiol ? disulfide transition is responsible for the water content of each membrane.     

Evaluation of Free-Fall Particle CT Images Using State Transition Matrix

Spatial particle density distribution images in a pipe cross section have been evaluated by means of state transition matrix, which is a parameter indicating the dominant particle density transition patterns among time series images consisting of CT 2-D space and 1-D time. State transition characterizes the transition patterns for positions in a cross section as monotonous transitions, sudden transitions, and extreme value transitions. In a simulation, the real part of the state transition matrix is negative and the imaginary part is zero in the case of monotonous transition. The real part is positive and the imaginary part is zero in the case of extreme value transition. The imaginary part is nonzero in the case of sudden transition. In free-fall particles in a vertical pipe, high, sudden, and extreme value transitions do not occur because the particle flow rate at this position is low, and therefore the probability of collision among particles is also low. High, sudden, and extreme value transitions occur near the pipe center when the particle flow rate is high, because the probability of collision among particles is high.     

Locational disadvantage of the hub

We show how spatial evolution is different between the two representative models of economic geography: [Krugman 99:483–499, 1991] and [Ottaviano et al. 43:409–436, 2002]. We analyze the impacts of falling transport costs on the spatial distribution of economic activities and welfare for a network economy consisting of three regions located on a line. It is normally considered that a hub city, i.e., a central region, always has locational advantage and manufacturing workers gain from trade. This is true in the former model, but not in the latter when markets are opened up to trade. This is because the price competition is so keen in the central region that the manufacturing sector moves to the peripheral regions, which aggravates the social welfare. We then show that when goods are close substitutes and share of manufacturing is of an intermediate level, the manufacturing activities completely disappear from the central region leading to a full agglomeration in one peripheral region.

Quantitative modeling for risk assessment of Vibrio parahaemolyticus in bloody clams in southern Thailand

A risk assessment of Vibrio parahaemolyticus in bloody clams (Anadara granosa) consumed in southern Thailand was conducted. This study estimated the prevalence and concentration of pathogenic V. parahaemolyticus in bloody clams at harvest and retail stages; and during this process, methods to detect the total and pathogenic V. parahaemolyticus were investigated. Consumption of bloody clams and cooking efficiency were studied using interviews and onsite observation of consumers. A beta-Poisson dose–response model was used to estimate probability of illness applying estimation methods for the most likely parameter values presented by USFDA. Microbial and behavioral data were analyzed by developing a stochastic model and the simulation gave a mean number of times a person would get ill with V. parahaemolyticus by consuming bloody clams at 5.6 × 10^− 4/person/year. Sensitivity analysis demonstrated the fraction of people who did not boil the clams properly was the primary factor in increasing risk. This study serves as an example of how a microbiological risk assessment with limited data collection and international cooperation leads to valuable local insight.     

On the Controlling Factor of Catalyst Temperature in C3H8—Air Mixture

Catalytic combustion of propane-air mixture was investigated.Platinum catalysts over a flat stainless steel with γ-alumina washcoat were employed.The employed burner has three catalysts set parallel to the mixture flow,spaced at an interval of 5,10 and 15 mm.Both experiment and numerical simulation were made at inlet temperature of 553 K,inlet velocity of 3 to 7 m/s and equivalence ratio of 0.3 to 0.5.In the numerical simulation,two-dimensional,steady state model was developed to calculate the temperature and species concentration in gas-phase.In this model.chemical reaction on the catalyst surface and that in the gas phase were assumed to occur in three-steps.The numerical results show good agreement with experimental results.It was found that the properties of the catalyst strongly affect the catalyst surface temperature.Especially,the thermal conductivity of catalyst has a great effect,while the emissivity of catalyst has less effect.     

Frequency and clinical correlates of occlusive lesions of cerebral arteries in Japanese patients without stroke. Evaluation by MR angiography

BACKGROUND: In order to provide a morphological basis for the understanding of the role of nitric oxide (NO) in autonomic preganglionic neurons, the present study was designed to clarify the localization and distribution of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity, a marker of NO synthase, in the rabbit spinal cord. METHODS: 11 Chinchilla rabbits of both sexes were used in this study. Animals were kept under conditions of controlled light and heat regimens. NADPH-d activity was examined by histochemical methods. RESULTS: The presence of NADPH-d activity in the spinal cord was detected in the dorsal horn, around the central canal (lamina X) and in autonomic preganglionic neurons. Focused on the latter, there was a prominent NADPH-d activity between T1 and L5 segments in the intermediate zone and less intensive NADPH-d staining between S1 and S3 segments. Differences between the two parts of the autonomic system were seen in the arrangement (periodical in sympathetic, and continuous in parasympathetic), in the length of neuronal processes length (shorter in sacral preganglionic neurons) and in their localization (both are seen in the intermediolateral nucleus, but neurons of the sympathetic autonomic system can be found also medially towards the central canal, whilst those of the parasympathetic system were not). CONCLUSIONS: The present results suggest that NO can be used as a transmitter in preganglionic neurons and can be involved in autonomic and sensory processes. (Fig. 10, Ref. 37.)