Serological survey of antibody to Neospora caninum in Japanese dogs

Prevalence of antibody to Neospora caninum (NC) in Japanese dogs were examined. The antibody was positive in 15 of 48 dogs (31.3%) reared in the dairy farms that had case of the abortions due to NC infection or had the cattle seropositive to NC, whereas the prevalence was 7.1% (14 of 198 dogs) among the dogs kept in urban areas. In one dog breeder, all 17 Shetland sheepdogs older than 7 months were seropositive, and one pup was diagnosed as neosporosis 2 months before the first serological examination. The antibody titers of the dogs kept at this breeder were almost unchanged for 1.5 years. Serological evidence of the dogs in the dairy farms and urban areas indicates the transmission of NC between dogs and cattle. Also serological results of the dogs in one breeder may suggest the potential horizontal transmission among dogs.     

Diffusion of cobalt,chromium, and titanium in Ni3Al

Diffusion studies of cobalt, chromium, and titanium in Ni₃Al (γ′) at temperatures between 1298 and 1573 K have been performed using diffusion couples of (Ni-24.2 at. pct Al/Ni-24.4 at. pct Al-2.91 at. pct Co), (Ni-24.2 at. pct Al/Ni-23.1 at. pct Al-2.84 at. pct Cr), and (Ni-24.2 at. pct Al/Ni-20.9 at. pct Al-3.17 at. pct Ti). The diffusion profiles were measured by an electron probe microanalyzer, and the diffusion coefficients of cobalt, chromium, and tita-nium in γ′ containing 24.2 at. pct Al were determined from those diffusion profiles by Hall’s method. The temperature dependencies of their diffusion coefficients (m[su2]/s) are as follows: ~D_(Co) = (4.2 ± 1.2) × 1O^-3exp {-325 ± 4 (kJ/mol)/RT} ~D_(Cr) = (1.1 ± 0.3) × 10^-1 exp {-366 ± 3 (kJ/mol)/RT} and D_(Ti) = (5.6 ± 3.1) × 10¹ exp {-468 ± 6 (kJ/mol)/RT} The values of activation energy increase in this order: cobalt, chromium, and titanium. These activation energies are closely related to the substitution behavior of cobalt, chromium, and titanium atoms in the Ll₂ lattice sites of γ′; the cobalt atoms occupying the face-centered sites in the Ll₂ structure diffuse with the normal activation energy, whereas the titanium atoms oc-cupying the cubic corner sites diffuse with a larger activation energy that includes the energy due to local disordering caused by the atomic jumps. The chromium atoms which can occupy both sites diffuse with an activation energy similar to that of cobalt atoms.     

Metabolism of tetramethrin isomers in rat: IV. Tissues responsible for formation of reduced and hydrated metabolites

1. To identify the sites of formation of the reduced metabolites, 3-hydroxy-cyclohexane-1,2-dicarboximide (3-OH-HPI-1 and -2), 1,2-cyclohexanedicarboxylic acid (TCDA) and 1-hydroxy-1,2-cyclohexanedicarboxylic acid (1-OH-HPA), in rat treated with 14C-labelled (1RS, trans)-tetramethrin, [3,4,5,6-tetrahydrophthalimidomethyl (1RS, trans)-chrysanthemate], bile-duct cannulated animals were orally or intravenously administered 14C-labelled 3,4,5,6-tetrahydrophthalimide (TPI) or 3,4,5,6-tetrahydrophthalic acid (THPA), precursors of these metabolites, and bile, urine and faeces were collected for analysis. 2. 3-OH-HPI-1 and 3-OH-HPI-2, which are cis-form reduced metabolites, and 1-OH-HPA were detected in bile and urine samples of the bile-cannulated rat treated intravenously and orally with 14C-labelled TPI, indicating their formation in tissues or blood. TCDA, a trans-form reduced metabolite, was not detected in bile, urine or faeces of the bile-cannulated rat treated intravenously with 14C-THPA, but was found in the faeces after oral application, indicating formation in the gastrointestinal tract. 3. To clarify whether 1-OH-HPA is produced from THPA via TCDA (hydroxylation via reduction) or by direct addition of H2O to its double bond (hydration), rats were orally administered 14C-labelled TCDA, and metabolites in urine and faeces were analysed. The observed lack of 1-OH-HPA indicated formation by direct addition of H2O to the double-bond of THPA. 4. To specify which tissues form reduced and hydrated metabolites, in vitro metabolism studies were carried out. Reduction to the cis-form was found to take place in blood cells, reduction to the trans-form took place in the gastrointestinal tract contents, and hydration took place in the liver and the intestinal tract contents.     

An extreame disposition method for low-level radioactive wastes using supercritical water (3)

Disposition of low-level radioactive wastes has been performed in supercritical water with RuO₂ as a catalyst without the addition of any oxidizing materials. These wastes arose from nuclear power plants etc., constituting of nonflammable organic materials, such as fire resistant sheeting and rubber gloves. We investigated the distribution behavior of iron and cobalt attached to nonflammable organic materials, in solid, liquid and gas phases during the decomposition of this method. The distributions of these elements under various conditions (initial amounts) were determined by using their radioisotopes as simulated low-level radioactive wastes in order to ease the detection of trace amounts of elements even in solid and gas phases. Iron and cobalt were found only in the solid phase when non-radioactive iron hydroxide was added as a precipitation reagent before the supercritical-water reaction.     

Measurement of large negative reactivity of an accelerator-driven system in the Kyoto University Critical Assembly

Large negative reactivity of a subcritical system driven by a pulsed 14 MeV neutron source has been measured in the Kyoto University Critical Assembly. The subcriticality of the accelerator-driven system (ADS) ranged in effective multiplication factor roughly from 0.98 to 0.92, which corresponded to an operational range of an actual ADS proposed by Japan Atomic Energy Agency. As the measurement technique, pulsed neutron method, power spectral analysis for pulsed neutron source, accelerator-beam trip method were employed. From neutron count decay data obtained by the pulsed neutron experiment, not only the prompt-neutron decay constant of fundamental mode but also a higher spatial mode could be derived. The subcriticality was also determined from the fundamental decay constant. The measured cross-power spectral density consisted of a familiar correlated reactor-noise component and many uncorrelated delta-function-like peaks at the integral multiple of pulse repetition frequency. The fundamental prompt-neutron decay constant, i.e., the subcriticality determined from the latter uncorrelated peaks was consistent with that obtained by the above pulsed neutron experiment. However, the magnitude of the former correlated component was reduced with an increase in the subcriticality and eventually this component became almost white at deeply subcritical state ranging in the multiplication factor under 0.95. Consequently, the determination of the decay constant from the correlated component was impossible under such a subcritical state. As data analysis method for the beam trip experiment, both the conventional integral count method and the least-squares inverse kinetics method (LSIKM) were employed. The LSIKM analysis led to the consistent subcriticality with that obtained by the pulsed neutron experiment, while the integral count method significantly underestimated the subcriticality. This underestimation originated from a residual background count, which was maintained after the beam trip. The LSIKM was mostly not influenced by such a slight count rate.     

Conceptual core design of Advanced Recycling Reactor based on mature technologies

This paper presents about comprehensive investigations into Advanced Recycling Reactor (ARR) based on existing and/or mature technologies (called “Early ARR”), aiming transuranics (TRU) burning and considering harmonization of TRU burning capability, technology readiness, economy and safety. The ARR is a 500 MW_e (1180 MW_th) oxide fueled sodium cooled fast reactor, which the low core height of 70 cm and the large structure volume fraction with 1.0 mm of cladding thickness to tube wall have been chosen among 14 candidate concepts to reduce the TRU conversion ratio (CR) and the void reactivity, taking technology readiness into account. As a result of nuclear calculation, the ARR has TRU burning capability from 19 to 21 kg/TW_thh and is sustainable in recycling. And the ARR can accept several kinds of TRU; the LWR uranium oxide fuels, LWR-MOX used nuclear fuel, and TRU recycled in this fuel cycle and the ARR is also flexible in TRU management in ways that it can transform from TRU CR of 0.56 to breeding ratio (BR) of 1.03. In addition, it has been confirmed that the ARR core conforms to the set design requirements; the void reactivity, the maximum linear heat rate, and the shutdown margin of reactivity control system. It has been confirmed that the closed fuel cycle with the ARR plants of 180 GW_th will not release TRU outside and generate more electricity by 65% compared with the present nuclear power system in the US, curbing the risk of nuclear proliferation. Thus the study can conclude that the Early ARR is able to close nuclear fuel cycle, using mature technologies and has features of the sustainability in recycling, and the accommodation of almost all the TRU at present and in the future, and the flexibility in TRU management with breakeven core.     

A fast method for the determination of the efficiency coefficient of bare CR-39 detector

A fast and simple method for the determination of the efficiency coefficient (η) of bare CR-39 detector is presented and discussed. The efficiency coefficient of bare CR-39 detector is then calculated by different ways and the obtained values are found to be comparable to each other. The average value of η of bare CR-39 is found to be 0.20 ± 0.01 tracks cm⁻² day⁻¹ per Bq m⁻³.     

Molecular characterization of Xenopus embryo heparan sulfate. Differential structural requirements for the specific binding to basic fibroblast growth factor and follistatin

Enzymatic elimination of heparan sulfate (HS) causes abnormal mesodermal and neural formation in Xenopus embryos, and HS plays an indispensable role in establishing the embryogenesis and tissue morphogenesis during early Xenopus development (Furuya, S., Sera, M., Tohno-oka, R., Sugahara, K., Shiokawa, K., and Hirabayashi, Y. (1995) Dev. Growth Differ. 37, 337-346). In this study, HS was purified from Xenopus embryos to investigate its disaccharide composition and binding ability to basic fibroblast growth factor (bFGF) and follistatin (FS), the latter being provided in two isoforms with core sequences of 315 and 288 amino acids (designated FS-315 and FS-288) originating from alternative mRNA splicing. Disaccharide composition analysis of the purified Xenopus HS showed the preponderance of a disulfated disaccharide unit with uronic acid 2-O-sulfate and glucosamine 2-N-sulfate, which has been implicated in the interactions with bFGF. Specific binding of the HS to bFGF and FS-288, the COOH-terminal truncated form, was observed in the filter binding assay, whereas HS did not bind to FS-315, indicating that the acidic Glu-rich domain of FS-315 precluded the binding. The binding of the HS to bFGF or FS-288 was markedly inhibited by heparin (HP) and various HS preparations, but not by chondroitin sulfate, supporting the binding specificity of HS. The binding specificity was further investigated using FS-288 and bovine intestinal [3H]HS. Competitive inhibition assays of the HS binding to FS-288 using size-defined HP oligosaccharides revealed that the minimum size required for significant inhibition was a dodecasaccharide, which is larger than the pentasaccharide required for bFGF binding. The binding affinity of FS to HS increased in the presence of activin, a growth/differentiation factor, which could be inactivated by direct binding to FS. These results, taken together, indicate that the structural requirement for binding of HS to bFGF and FS is different. HS may undergo dynamic changes in its structure during early Xenopus embryogenesis in response to the temporal and spatial expression of various growth/differentiation factors.     

Cloning and characterization of cDNAs encoding S-RNases from almond (Prunus dulcis): primary structural features and sequence diversity of the S-RNases in Rosaceae

The ability of histamine H3 receptor ligands to interact with 5-HT3 receptors in NG108-15 cells was studied using the whole cell patch clamp recording technique. Imetit, a histamine H3 receptor agonist, generated inward currents and exhibited weak partial agonist activity at the 5-HT3 receptor (EC50 = 11.8 microM). Imetit-induced currents were slow to desensitize and at a high concentration reduced in size. The histamine H3 receptor antagonists iodophenpropit and thioperamide did not generate inward currents but were able to inhibit 5-hydroxytryptamine (5-HT) responses with an IC50 of 1.57+/-0.3 microM and 13.7+/-3.5 microM, respectively. Thioperamide is probably a non-competitive antagonist which may have more than one binding site on the receptor.     

Effect of different features to drill-wear prediction with back propagation neural network

In this paper, a back propagation neural network (BPNN) has been applied to predict the corner wear of a high speed steel (HSS) drill bit for drilling on different workpiece materials. Specially defined static and dynamic features extracted by a wavelet packet transform (WPT) from the resultant force converted from thrust and torque together with the cutting conditions (workpiece material, spindle speed, drill diameter, feed rate) are used as inputs to train the network to obtain a better output, drill corner wear. Drilling experiments have been carried out over a wide range and, features newly defined and conventional ones, features extracted from different frequency bands are compared.