Re-evaluation of Radiation-Energy Transfer to an Extraction Solvent in a Minor-Actinide-Separation Process Based on Consideration of Radiation Permeability

ABSTRACT

Absorbed-dose estimation is essential for evaluation of the radiation tolerance of minor-actinide-separation processes. We propose a dose-evaluation method based on radiation permeability, with comparisons of heterogeneous structures seen in the solvent-extraction process, such as emulsions forming in the mixture of the organic and aqueous phases. A demonstration of radiation-energy-transfer simulation is performed with a focus on the minor-actinide-recovery process from high-level liquid waste with the aid of the Monte Carlo radiation-transport code PHITS. The simulation results indicate that the dose absorbed by the extraction solvent from alpha radiation depends upon the emulsion structure, and that from beta and gamma radiation depends upon the mixer-settler-apparatus size. Non-negligible contributions of well-permeable gamma rays were indicated in terms of the plant operation of the minor-actinide-separation process.     

An efficient manufacturing method for I-shaped cross-sectional CFRP beam with arbitrary arrangement of carbon fiber using electro-activated resin molding

Abstract

The I-shaped cross-sectional beam of CFRP (CFRP I-beam) is usually manufactured by the continuous protrusion method. Carbon fibers can only be arranged in the longitudinal direction. The CFRP I-beam with arbitrary arrangement of carbon fiber was manufactured with applying the electro-activated deposition molding method. The carbon fiber fabric was immersed in the deposition solution and energized, epoxy resin precipitated around carbon fiber and impregnated. The resin-impregnated fabric was installed to the mold, and the CFRP I-beam was fabricated. The CFRP I-beam was subjected to three-point bending tests, and the relationship between load-deflection was simulated by finite-element analysis.     

A feasibility study of a direct-mapping parallel processing method to solve linear equations in load-flow calculation

With the growing size and complexity of power systems, system analysis—such as transients calculation—takes much time. Hence, fast calculation methods are required. Although parallel processing is a hopeful method, there have been difficulties in the parallel solution of linear equations which appear in power-flow calculations by the Newton-Raphson method. This paper aims at the fast calculation of the power-flow problem by means of parallel processing. In order to improve the suitability to the parallel solution of the differential equation in transients calculation, we assume the use of a direct-mapping parallel processing machine to map directly the network of a power system onto a network of processors. Under this assumption, we propose a new parallel-processing-oriented method in which the linear equation is solved by linear iterations between nodes with Aitken acceleration. We simulate the method on three model power systems and compare this Parallel Iterative Method (PIN) with a Parallel Direct Method (PDM) which uses the banded matrix according to the number of operations required. As a result, we can expect that PIM may solve linear equations faster than PDM with m processors, although the PIM might be inferior to the PDM with m × m processors, where m denotes the half-band width of the banded matrix.     

Competitive inhibition by procaine of carbachol-induced stimulus-secretion coupling in rat pancreatic acini

1. Procaine (0.03-10 mM) inhibited carbachol (CCh)-induced amylase release from rat isolated pancreatic acini in a competitive manner. Kinetic analysis of the relation between CCh concentrations and the amount of amylase released in the presence of various procaine concentrations indicated that procaine caused competitive inhibition with the affinity constant (pA2) value of 5.00 +/- 0.08. 2. Receptor binding assay confirmed that procaine (0.01-10 mM) competitively inhibited [N-methyl-3H]-scopolamine chloride ([3H]-NMS) binding to its receptor with binding affinity (pKi) of 4.63 +/- 0.10. 3. Procaine transformed CCh-evoked [Ca2+]i dynamics: the initial rise in [Ca2+]i followed by a gradual decay during continuous stimulation with 3 microM CCh was transformed by 0.3 mM procaine to the oscillatory [Ca2+]i dynamics, which resembled the response to 0.3 microM CCh in the absence of procaine. The initial phase of [Ca2+]i oscillation corresponded to the initial phase of CCh-induced amylase release in isolated perfused acini. 4. Procaine (0.3-3 mM) did not inhibit the secretory response to cholecystokinin octapeptide (CCK-8) in isolated incubated acini. A higher concentration of procaine (10 mM) caused weak but significant inhibition of the response to only limited concentrations of CCK-8, 30 and 100 pM. Procaine lower than 10 mM was ineffective on [125I]-BH-CCK-8 binding, although procaine (10 mM) caused weak but significant inhibition of the binding.     

Surgical pitfalls in pinealoma surgery

The author has treated 30 cases of pinealoma by the infratentorial supracerebellar approach with the patient in the sitting position. Long-term outcome has been excellent in 26 cases, poor in 1, and death in 3 cases. Postoperative deaths were due to: (i) high venous pressure in the jugular vein caused by a tourniquet placed around the neck to prevent air-embolism, making hemostasis more difficulty, (ii) the absence of retraction resulting in a narrow surgical field when acute brain swelling developed, and (iii) high coagulation and ablation of the precentral cerebellar vein causing diffusion thrombosis of deep veins. The details of these cases are presented in this article.     

Generation of adaptive gait patterns for quadruped robot with CPG network including motor dynamic model

This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environments. The CPGs act as the flexible oscillators of the joints and adjust joint angles to required values. The CPGs are interconnected with each other and sets of their coupling parameters are adjusted by a genetic algorithm so that the quadruped robot can realize stable and adequate gait patterns. Generation of gait patterns results in the formation of the CPG networks suitable for the formation of not only a straight walking pattern but also of rotating gait patterns. Experimental results demonstrate that the proposed CPG networks are effective for the automatic adjustment of the adaptive gait patterns for the tested quadruped robot under various environments. Furthermore, the target tracking control based on image processing is achieved by combining the general gait patterns. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 35–43, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20225     

Stereoscopic synthesized brain-surface imaging with MR angiography for localization of a peripheral mycotic aneurysm: case report

A patient with subacute bacterial endocarditis and a peripheral mycotic aneurysm is presented. We used a combined multi-slice surface anatomy scanning (SAS) and contrast-enhanced MR angiography image to determine the exact location of the small lesion by applying a skin marker on the scalp and visualizing the relationship of the marker to the brain surface structures and to the lesion. This technique was useful for the removal of a small peripheral aneurysm using only a limited craniotomy.     

Estimation of the functional reserve of the human liver by urinary D-glucaric acid excretion after vitamin C administration

Increased monoamine metabolism in experimental herpes simplex virus (HSV) encephalitis is well established. Both serotonin (5-HT) and dopamine (DA) systems are affected. HSV invades the raphe nuclei after its entry into the brain stem. However, no studies have been published concerning influences of HSV on the neurotransmitters in the raphe. In the present study, concentrations of 5-HT and DA and their metabolites in the raphe nuclei and related brain regions in rabbits with fulminant HSV encephalitis have been analyzed using high-pressure liquid chromatography. Encephalitis was induced by corneal inoculation with HSV. Homovanillic acid (HVA) and dihydroxyphenyl acetic acid (DOPAC) concentrations and HVA/DA ratios were increased in the raphe nuclei suggesting increased DA turnover. The most substantial changes were bilaterally decreased 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the raphe nuclei. The decrease in the raphe 5-HT was reflected also to the projection areas in the hemispheres, where 5-HT concentrations were lower in HSV-inoculated rabbits than in controls. The changes strongly suggest a direct influence of HSV on serotoninergic neurons. Since the ventral parts of the limbic system have rich serotoninergic afferents from the raphe, this also suggests that HSV may reach hemispheres in HSV encephalitis from the brain stem via the ascending serotoninergic system.     

Tyrosine phosphorylation as a convergent pathway of heterotrimeric G protein- and rho protein-mediated Ca2+ sensitization of smooth muscle of rabbit mesenteric artery

1. The aim of this study was to determine whether different signal transduction mechanisms underlie the Ca2+ sensitizing effects of guanosine 5'-O-(3-thiotriphosphate) (GTP(gamma)S) and receptor agonists on beta-escin-skinned smooth muscle of rabbit mesenteric artery. 2. In the homogenate of the beta-escin-skinned arterial strip, C3 exoenzyme of Clostridium botulinum catalyzed the [32P]-ADP-ribosylation of only one protein that had the same molecular mass as the protein detected in Western blots with anti-rho p21 antibody. Pretreatment of preparations with C3 resulted in great inhibition of GTP(gamma)S-induced Ca2+ sensitization, although the effect of GTP(gamma)S at higher concentrations (> or = 30 microM) was not completely blocked by this treatment. In contrast, the enhancement by phenylephrine and histamine, in the presence of guanosine 5'-triphosphate, of the Ca2+-induced contraction was not affected by C3 pretreatment. 3. The protein kinase C (PKC) inhibitors calphostin C and staurosporine completely eliminated the enhancement by phorbol ester 12,13-dibutyrate of the Ca2+-induced contraction. However, these PKC inhibitors had no effect on GTP(gamma)S- and receptor agonist-induced Ca2+ sensitization. 4. The tyrosine kinase inhibitors genistein and tyrphostin 25 caused an irreversible and complete block of the enhancement by GTP(gamma)S of the Ca2+-induced contraction without affecting this Ca2+ contraction. The inactive genistein analogue daidzein did not modify the effect of GTP(gamma)S. The Ca2+ sensitizing effects of phenylephrine and histamine were also blocked by these tyrosine kinase inhibitors. 5. These results suggest that rho p21 predominantly mediates GTP(gamma)S-induced Ca2+ sensitization of beta-escin-skinned smooth muscle of rabbit mesenteric artery, while the Ca2+ sensitizing actions of heterotrimeric G protein-coupled receptor agonists do not involve this small G protein. However, it seems that tyrosine phosphorylation, but not PKC activation, plays an important role in both of the rho p21 protein- and heterotrimeric G protein-mediated Ca2+ sensitization mechanisms.