Systemic administration of CCK-8S, but not CCK-4, enhances dopamine turnover in the posterior nucleus accumbens: a microdialysis study in freely moving rats

The present study was carried out to examine the effects of peripheral administration of sulfatedcholecystokinin octapeptide (CCK-8S) on dopamine (DA) turnover in the posterior nucleus accumbens (PNAc) and the caudate-putamen (CP) in awake rats. Microdialysis was used to quantify the extracellular concentrations of DA and its two metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). Intraperitoneal injections of CCK-8S (0.3 mg/kg b.wt.) caused a significant increase in DOPAC and HVA concentrations in the PNAc, but did not affect the DA level. Such increases in the metabolite contents were not found in the CP. Similar injections of vehicle (1% NaHCO3 solution, 1 ml/kg b.wt.) did not have an effect in either brain region. In an attempt to determine the type of receptor involved in the CCK-8S-induced changes, CCK tetrapeptide (CCK-4, 0.3 mg/kg b.wt.) known to have high affinity for CCKB subtype or vehicle (10% DMSO-saline, 1 ml/kg b.wt.) was administered intraperitoneally. Neither CCK-4 nor vehicle caused significant changes in any of extracellular DA, DOPAC and HVA contents in the PNAc. These results suggest that peripherally administered CCK-8S has stimulatory effects on the dopaminergic system in the PNAc, and raise the possibility that the effect appears to be mediated via CCKA receptors.     

Comparative study on poly(3-alkylpyrroles)

Polypyrrole(PPY), poly(3-methylpyrrole)(PMPY) and poly(3-octylpyrrole) (POCPY) were prepared under the same electrochemical polymerization conditions and their properties were comparatively studied. Electrical conductivity increased in the order POCPY < PMPY < PPY. Absorption spectra measuredin situ showed that while peak energy of the interband transition increased in the order PPY < PMPY < POCPY, the absorption edge of PPY was located at almost equal energy as that of PMPY and POCPY. Stability, indicated by decrease in the ratio of conductivities after storage to the initial conductivity, was primarily dependent on the length of alkyl chains, secondly on dopants and associated with spectral deterioration. While the initial conductivity was strongly dependent on temperature and current density during electrochemical polymerization, the stability was virtually independent of these conditions. The stability increased in the order: POCPY < PMPY < PPY. Spectral change during storage in air was dependent on the chemical structure of polymers but almost independent of dopants. The spectral change indicated PPY to be in nearly initial states after 10 days and POCPY to be in almost completely undoped states after 200 days. In cyclic voltammograms, PPY and POCPY showed one anodic peak and PMPY two anodic peaks. Their peak potentials were associated with conjugation length.     

Analysis of 3-line generalized Feistel networks with double SD-functions

Generalized Feistel networks (GFN) are broadly employed in the design of primitives for block ciphers, stream ciphers, and hash functions. Lately, endowing the functions of GFNs with the structure of nonlinear substitution followed by linear diffusion (substitution-diffusion, SD) has received a great deal of attention. In this contribution, we prove tight lower bounds on the number of differentially and linearly active S-boxes for 3-line GFNs with double SD-functions where two SD-structures are applied one after another. We also show 8-round impossible differentials for 3-line GFNs with bijective functions. Moreover, we demonstrate that the proportion of active S-boxes in all S-boxes for such GFNs is by up to 14% higher than that for 4-line GFNs with double SD-functions, when instantiated with MDS matrices. This indicates that, rather surprisingly, the 3-line GFNs can be more efficient in practice than those with 4 lines.     

Sensing of small signals on CRT-displayed medical radiographs after A/D conversion

The paper describes an experimental evaluation, by ROC analysis, of displayed CRT images after digitisation of analogue medical radiographs. Two types of images were used in these studies: (1) images of 2 mm diameter beads, and (2) images of 2 mm diameter cavities. The psychophysical experiment was carried out by obtaining ROC curves based on signal detection theory. Detectability was evaluated as the ‘area under the ROC curve’. It was found that the detectabilities of images on the CRT were significantly lower than those of the original images. As for the images of bead signals, the ‘areas under the ROC curve’ were 0.91 and 0.70 for the original images and the digital images respectively. However, the ‘area under the ROC curve’ could be improved to 0.84 or 0.80 by a multi-cycled display going through 2 or 4 cycles of contrast enhancement in the studies of bead images. The ‘area under the ROC curve’ of the cavity images was better than that of the beads.     

Polymerization of methyl methacrylate by metallocenes

Attempts at polymerizing methacrylate using metallocenes are reported. Polymerization is successful using ferrocene in a ketone solution, but not in benzene or without a solvent. Ketones are effective in the order: methyl ethyl ketone < cyclohexanone < cycloheptanone. Carbon tetrachloride has an accelerative effect on the polymerization in benzene and methyl ethyl ketone solutions, but no effect in cyclohexanone solution. Some binary systems, which consist of ferrocene and higher valence compounds such as cobalt trisacetylacetonate, are effective redox initiators. Cobaltocene polymerizes methyl methacrylate in the presence of carbon tetrachloride; zirconocene dichloride induces polymerization of methyl methacrylate in a cyclohexanone solution; whereas neither nickelocene nor titanocene dichloride are effective. Styrene and acrylonitrile were not polymerized by the metallocenes examined.     

Effect of siloxane chain lengths of monomers on characteristics of pervaporation membranes prepared by plasma polymerization

Plasma-polymerized membranes were prepared from a series of monomers with the different siloxane chain lenghts, i. e., hexamethyldisiloxane, octamethyltrisiloxane, and decamethyltetrasiloxane, and effects of the starting monomers on both the structures of the plasma polymers and the pervaporation characteristics of ethanol/water mixture were investigated. By IR and XPS measurements, it was found that with increase of the siloxane chain lenghts of the monomer the siloxane chains in the plasma polymers were linked more continuously and smaller amounts of additional oxygen were newly incorporated into the polymers. All membranes obtained from the three monomers were found to be ethanol-permselective. From the standpoint of obtaining both high selectivity and high permeation rate, the monomer with the longer siloxane chain was profitable. The relations between the results of the analysis of the plasma polymers by IR and XPS measurements and the pervaporation characteristics obtained are discussed. © 1994 John Wiley & Sons, Inc.     

Effects of valence states of iron in iron phosphates on the catalytic activity in oxidative dehydrogenation of isobutyric acid

Oxidative dehydrogenation of isobutyric acid to methacrylic acid was studied over an iron phosphate catalyst with a P/Fe atomic ratio of 1.2. The freshly prepared catalyst consisting of Fe³⁺ is reduced with isobutyric acid to iron(II) pyrophosphate [Fe₂P₂O₇] via a bluish black intermediate. Under the reaction conditions, the fresh catalyst is reduced gradually to the intermediate and the Fe₂P₂O₇ is also reoxidized to the intermediate. However, both the catalytic activity and the selectivity were scarcely affected with a large variation in the valence states of iron in the bulk of iron phosphate. On the other hand, the studies on the reaction in the absence of oxygen revealed that the reaction is promoted by the redox cycle of iron phosphate.     

叶片表面旋涡脱落诱发自激振动的可能性

在循环水槽中对微弯薄翼在其失速角附近自激振动的可能性进行了试验研究。采用闪烁激光成像法和高速摄影法两种不同的方法对流场进行了可视化。作用在翼型上的力矩由应变片测定。为了验证旋涡脱落是否会引起翼型自激振动,对该翼型进行了强迫振动试验。通过改变振动的频率和振幅确定了翼型在不同冲角下的连锁区域。在连锁区域内,根据翼型的振动位移和力矩之间的相位差对旋涡脱落是否会诱发翼型自激振动进行了判断。     

Switchgear component commonality design based on trade-off analysis among inventory level,delivery lead-time and product performance

The shortening of product delivery lead-times can usually be achieved by keeping high-level components in inventory, however in small-volume production systems, maintaining such inventories is often a costly as well as a risky business strategy. If the risk of maintaining unsold inventory can be decreased, even small-volume manufacturers may be able to justify holding more significant quantities of versatile inventory. This paper discusses a component commonality effect to breakthrough the trade-off relationship between inventory levels and delivery lead-times for such small-volume production systems. By using the same component in different products, inventory maintenance costs can be dramatically reduced, but component commonality design problems are inherently complex, since excessive module commonality may lead to lower product performances, and there are trade-off relationships between product performance and cost reductions obtained through component commonality. In this paper, such a design problem is formulated as a multiobjective component commonality design optimisation problem considering inventory level, delivery lead-time and product performance, and the optimal solutions are obtained as a Pareto optimal solution set. Detailed procedures concerning the proposed design method, including inventory simulation, are discussed and developed for a switchgear design problem. Finally, an example switchgear design problem is solved to illustrate that optimal use of component commonalities across different modules can significantly reduce inventory costs, while also shortening product delivery lead-times.     

Development of Nb3Sn superconducting wires for high field magnets at Kobe Steel and JASTEC

Research and development activities and some recent results related to Nb₃Sn superconducting wires in Kobe Steel, Ltd. (KSL) and Japan Superconductor Technology Inc. (JASTEC) are introduced. First, an outline of the activities is described briefly from a historical point of view. Following that, improvements in the characteristics (i.e., critical current density (J_c), n-value and mechanical properties) of bronze-processed Nb₃Sn wires are reviewed. Finally, the status of development for the Ta–Sn powder-in-tube (TS-PIT) process is briefly discussed.