Korormicin, a novel antibiotic specifically active against marine gram-negative bacteria, produced by a marine bacterium

A novel antibiotic named korormicin was isolated from the marine bacterium, Pseudoalteromonas sp. F-420. This strain was isolated from the surface of a macro alga Halimeda sp. collected from Palau (the Republic of Belau). The planar structure of korormicin was determined by the result of 2D NMR studies and mass spectral data. Korormicin had specific inhibitory activity against marine Gram-negative bacteria, but was inactive against terrestrial microorganisms.     

Temperature Effect on Removal of Sulfur Dioxide and Benzene in Humid Air by DC Corona Discharge

A DC corona discharge reactor was applied to remove sulfur dioxide (SO₂) and benzene (C₆H₆) from N₂‐O₂‐H₂O mixed gas in the temperature range from room temperature to 400 °C. When SO₂ was removed, the temperature elevation caused the decrease of the removal efficiency of SO₂. On the other hand, the removal efficiency of C₆H₆ was not significantly influenced by the temperature elevation. In the simultaneous removal of SO₂ and C₆H₆ in the relatively low temperature range below 200 °C, the removal efficiency of SO₂ is significantly inhibited by coexisting C₆H₆. When the simultaneous removal was conducted in the high temperature range, the removal efficiency of SO₂ was not sensitive against the coexisting C₆H₆. On the other hand, the removal efficiency of C₆H₆ was almost independent of coexisting SO₂ at all temperatures. A hypothesis of reaction mechanism was discussed based on radical reactions with SO₂ and C₆H₆ to explain the trend observed in the experiment.     

Molecular and genetic analysis of two patients with Bernard-Soulier syndrome--identification of new mutations in glycoprotein Ib alpha gene

We investigated two unrelated patients with Bernard-Soulier syndrome (BSS) by performing molecular and genetic analysis. A flow cytometric and immunoblotting analysis showed GP Ib alpha to be absent from the platelet membrane of both patients. Other glycoproteins that formed GP Ib/IX/V complex were present on the platelets, but in decreased amounts. Therefore, GP Ib alpha gene from both cases was sequenced after PCR amplification and subcloning. We identified a homozygous mutation of a dinucleotide deletion within the TGTG repeat at cDNA number 972 to 975 in GP Ib alpha gene from Case 1. In Case 2, compound heterozygosity was demonstrated in GP Ib alpha gene; an insertion of a single base (T) at cDNA number 1,418 in one allele, and a deletion of a single base (A) within the 7-adenine repeat at cDNA number 1,438 to 1,444 in another allele. The three new mutations in both patients appeared to cause a frameshift, which created a new termination codon shortly thereafter, and thus lead to a GP Ib alpha deficiency on the platelet membrane. Truncated mutant proteins could be detected in the plasma and platelets of Case 2, but not of Case 1. According to these findings, it is thus supposed that the properties and conformation of additional COOH-terminal peptides, which were supposedly synthesized as results of the mutations, may have an important role on the processing of mutant GP Ib alpha in megakaryocytes and platelets.     

The activity of calcium in calcium-metal-fluoride fluxes

The standard Gibbs energy of reaction Ca (1) +O (mass pct, in Zr) = CaO (s) has been determined as follows by equilibrating molten calcium with solid zirconium in a CaO crucible: ΔG° = -64,300(±700) + 19.8(±3.5)T J/mol (1373 to 1623 K) The activities of calcium in the CaO_satd-Ca-MF₂ (M: Ca, Ba, Mg) and CaO_satd-Ca-NaF systems were measured as a function of calcium composition at high calcium contents at 1473 K on the basis of the standard Gibbs energy. The activities of calcium increase in the order of CaF₂, BaF₂, and MgF₂ at the same calcium fraction of these fluxes. The observed activities are compared with those estimated by using the Temkin model for ionic solutions. Furthermore, the possibility of the removal of tramp elements such as tin, arsenic, antimony, bismuth, and lead from carbon-saturated iron by using calcium-metal-fluoride fluxes is discussed. Formerly Graduate Student, Department of Metallurgy, The University of Tokyo.     

A limiting amplifier with low phase deviation using an AlGaAs/GaAsHBT

The design and performance of an AlGaAs/GaAs HBT limiting amplifier are presented. It is revealed that the main cause of phase shift deviation in a limiting amplifier is the bias dependence of the input capacitance, which is the dominant nonlinear factor in a transistor. A circuit design featuring a differential configuration with an emitter peaking technique lowers phase deviation and widens the frequency band. The device achieves high-frequency operation of 15 GHz with a low phase shift deviation of 3° over a 15-dB input dynamic range     

Development of the double-rod-type jumper horns in strain assemblies with pipe jumpers for 500-kv transmission lines

This paper proposes double-rod-type jumper horns in strain assemblies with pipe jumpers for 500-kV transmission lines, the structure of which is very simple. It can be estimated that no corona discharge appears on the horns under the line voltage of 525 kV. The arc behavior on the double-rod-type jumper horns is similar to that on the single-rod-type horns. The arc can be held stably for 60 ms against strong wind (10 m/s). The stable duration increases more than 300 ms under windless condition, therefore the horns have been adopted for practical use.     

Effect of short-term administration of dexamethasone on canine antral gastrin gene expression

In a two-part study of the circumcision status of boys with urinary tract infections (UTIs), we reviewed the occurrence of UTIs in 209,399 infants born in US Army hospitals worldwide from 1985 to 1990. During the first year of life, 1,046 (0.5%: 550 girls and 496 boys) were hospitalized for UTIs. Noncircumcised male infants had a 10-fold greater incidence of infection than did circumcised male infants. The frequency rate of circumcision rose significantly, from 70.3% to 80.2%, during the study period. Among uncircumcised boys younger than 3 months with UTIs, 23% had concomitant bacteremia involving the same organism. The second part of the study consisted of a meta-analysis of all nine previous reports on the circumcision status of boys with UTIs. These studies revealed a fivefold to 89-fold increased risk of infection in uncircumcised boys; the combined data yielded a 12-fold increase in UTIs in this population. Parents should be told of the lower risk of UTIs for circumcised boys during informed-consent counseling.     

Modeling and control of carbon monoxide concentration using aneuro-fuzzy technique

Modeling and control of carbon monoxide (CO) concentration using a neuro-fuzzy technique are discussed. A self-organizing fuzzy identification algorithm (SOFIA) for identifying complex systems such as CO concentration is proposed. The main purpose of SOFIA is to reduce the computational requirement for identifying a fuzzy model. In particular, the authors simplify a procedure for finding the optimal structure of fuzzy partition. The δ rule, which is a basic learning method in neural networks, is used for parameter identification of a fuzzy model. SOFIA consists of four stages which effectively realize structure identification and parameter identification. The procedure of SOFIA is concretely demonstrated by a simple example which has been used in some modeling exercises. The identification result shows effectiveness of SOFIA. Next, the authors apply SOFIA to a prediction problem for CO concentration in the air at the busiest traffic intersection in a large city of Japan. Prediction results show that the fuzzy model is much better than a linear model. Furthermore, the authors simulate a control system for keeping CO concentration at a constant level by using the identified fuzzy model. A self-learning method for adaptively modifying controller parameters by δ rule is introduced because the dynamics of real CO concentration system changes gradually over a long period of time. Two self-learning controllers are designed in this simulation. One is a self-learning linear PI controller. The other is a self-learning fuzzy PI controller. The authors investigate robustness and adaptability of this control system for disturbance and parameter perturbation of the CO concentration model. Simulation results show that the self-learning fuzzy controller is more robust and adaptive     

Saccharide radicals induced by UV irradiation at room temperature

The stability of saccharide radicals induced by UV irradiation at room temperature and the ability to initiate polymerization of acrylamide were investigated. UV light of 220 < λ < 300 nm was proved to form saccharide radicals effectively at room temperature. ESR signal intensity of the irradiated saccharide was in the order of sucrose > methyl-α-D-glucopyranoside ? cellobiose > D-xylose > D-glucose α D-fructose. The saccharide radicals were fairly stable at room temperature, however, the markedly declined in amount as the samples were brought to their own melting points or allowed contact with water. When an aqueous solution of acrylamide was added to the irradiated saccharide, polymerization was initiated and the conversion increased with an increasing amount of the preirradiated saccharide. Regarding the kind of saccharide, the conversion decreased in the following order: sucrose > methyl-α-D-glucopyranoside > cellobiose > D-glucose, which indicated a good agreement with the magnitude of ESR signal intensity.