Partial information basis for agent-based collaborative dialogue

We propose a partial information state-based framework for collaborative dialogue and argument between agents. We employ a three-valued based nonmonotonic logic, NML3, for representing and reasoning about Partial Information States (PIS). NML3 formalizes some aspects of revisable reasoning and it is sound and complete. Within the framework of NML3, we present a formalization of some basic dialogue moves and the rules of protocols of some types of dialogue. The rules of a protocol are nonmonotonic in the sense that the set of propositions to which an agent is committed and the validity of moves vary from one move to another. The use of PIS allows an agent to expand consistently its viewpoint with some of the propositions to which another agent, involved in a dialogue, is overtly committed. A proof method for the logic NML3 has been successfully implemented as an automatic theorem prover. We show, via some examples, that the tableau method employed to implement the theorem prover allows an agent, absolute access to every stage of a proof process. This access is useful for constructive argumentation and for finding cooperative and/or informative answers.     

Experimental identification of Biot's hydro-mechanical coupling coefficient for cement mortar

The objective of the present paper is to show an experimental method allowing the characterisation of Biot's hydro-mechanical coupling coefficient for cement mortar. This coefficient results from the mathematical formulation of a thermo-hygro-mechanical coupling model for non-saturated media [3, 8, 9, 11]. In the literature, the expression of Biot's coefficient is based on an empirical formula. The proposed method of its identification is bosed on two experiments: the dimensional variation tests and the characterisation of the elastic properties as a function of different relative humidity. We deduce Biot's coefficient by using the thermal-porous-elastic behaviour law of Coussy [2, 3]. In the literature, liquid Biot's coefficientb _l is often approached with the degree of liquid, saturationS _l . By comparing the results of liquid Biot's coefficientb _l determined experimentally and the coefficient of liquid saturationS _l , we show a good agreement between the two coefficients for small to moderate relative humidity. For important relative humidity (i.e. higher than 70%), the value of liquid Biot's coefficient is slightly lower than saturation.

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Résumé L'objectif de ce papier consiste à montrer une méthode expérimentale permettant la caractérisation du coefficient de couplage hydromécanique de Biot pour le mortier de ciment. Ce coefficient résulte de la formulation mathématique d'un modèle de couplage thermo-hygro-méchanique pour les milieux poreux non-saturés [3, 8, 9, 11]. Dans la littérature, l'expression du coefficient de Biot est basée sur deux expériences: l'essai de variation dimensionnelle et de caractérisation des propriétés élastiques à différentes humidités relatives. Nous déduisons ainsi le coefficient de Biot en se servant de la loi de comportement thermo-poro-élastique de Coussy [2, 3]. Dans la littérature, le coefficient de Biot liquide b_l est souvent rapproché avec le degré de la saturation liquide S_l. En comparant les résultats de ces deux coefficients, nous montrons une bonne concordance entre eux pour des humidités relatives faibles et moyennes. Par contre, pour des humidités relatives importantes (c'est-à-dire supérieures à 70%), nous trouvons que le coefficient de Biot liquide est légèrement inférieur au degré de la saturation.

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Editorial Note CSTB is a RILEM Titular Member.     

The effect of removable partial denture framework design on gingival inflammation: a clinical model

A clinical trial using the experimental gingivitis model developed for periodontal clinical research was performed to evaluate the effect of a removable partial denture mandibular major connector design on the surrounding gingival tissues. A comparison of the state of health of adjacent gingival tissues was made between the linguoplate (control) and cingulum bar (test) major connectors. Clinical parameters were recorded in a single-blind crossover experimental gingivitis trial. Subjects were brought to a level of optimal gingival health and then randomly assigned to use one framework design while refraining from any oral hygiene. Measurements were made at 7-day intervals for 21 days. The subjects were returned to optimal oral health and repeated the experimental period with the alternate design. Results showed a greater increase in mean gingival inflammation with the control than with the test removable partial denture, suggesting that the cingulum bar has fewer detrimental effects on gingival tissues than the linguoplate major connector. Results of this study suggest that the experimental gingivitis model can be a useful and valid system for studying the potential effects of a removable partial denture design on surrounding oral tissues.     

Time-level relationship for lipid peroxidation and the protective effect of alpha-tocopherol in experimental mild and severe brain injury

OBJECTIVE: Oxygen free radical-mediated lipid peroxidation has been proposed to be one of the major mechanisms of secondary damage in traumatic brain injury. The first purpose of this study was to establish the time-level relationship for lipid peroxidation in injured brain tissue. The second purpose was to examine the protective effect of alpha-tocopherol against lipid peroxidation. METHODS: For this study, 65 guinea pigs in five groups were studied. Five of the animals were identified as a control group, and the remaining 60 animals were divided equally into four groups (Groups A, B, C, and D). Mild injury (200 g x cm) (Groups A and C) and severe injury (1000 g x cm) (Groups B and D) were produced by the method of Feeney et al. Alpha-tocopherol (100 mg/kg) was administered intraperitoneally before brain injury in Groups C and D. Five animals from each group were killed immediately after trauma, five after 1 hour, and the remaining five animals after 36 hours. Lipid peroxidation in traumatized brain tissues was assessed using the thiobarbituric acid method. RESULTS: In all groups with traumatic brain injuries, levels of malondialdehyde, a lipid peroxidation product, were higher than in the control group. The amount of lipid peroxidation was increased by the severity of the trauma. Alpha-tocopherol significantly suppressed the rise in lipid peroxide levels in traumatized brain tissues. CONCLUSION: This study demonstrates that lipid peroxidation is increased by the severity of trauma and that alpha-tocopherol has a protective effect against oxygen free radical-mediated lipid peroxidation in mild and severe brain injury.     

Effect of tyrosine kinase and tyrosine phosphatase inhibitors on ATP- and thapsigargin-induced CA2+ entry in rat peritoneal macrophages

The production of eicosapentaenoic acid [20:5omega3; EPA] from Shewanella gelidimarina (ACAM 456T) was investigated with respect to growth temperature and growth on sole carbon sources. The percentage and quantitative yield of EPA remained relatively constant at all growth temperatures within or below the optimal growth temperature region. At higher growth temperatures, these values decreased greatly. Growth on differing sole carbon sources also influenced the percentage and amount of EPA produced, with the fatty acid composition influenced by provision of potential acyl chain primers as sole carbon sources. The highest amounts of EPA occurred from growth on propionic acid and L-leucine respectively, while the highest percentage of EPA occurred from growth on L-proline. Monounsaturated fatty acid components and EPA were concentrated in phosphatidylglycerol (PG), while the proportion of branched-chain fatty acids was elevated in phosphatidylethanolamine (PE); the two major phospholipid classes. Specific associations of EPA with other acyl chains were identified within cellular phospholipid classes. The association of EPA with 17:1 and 18:0 acyl chains in phospholipid species was specific to PG, whereas the association of EPA with i13:0/13:0 and 14:0/i14:0 was specific to PE. Such acyl chain 'tailoring' is indicative of the important role of EPA in bacterial membrane adaptive responses. EPA was also a large component (22%) of a non-esterified fatty acid (NEFA) fraction within the total lipid extract of the bacterium. This may point toward a particular role of NEFA in polyunsaturated fatty acid (PUFA) metabolism. The formation of EPA was investigated by labelling with L-[U-14C]serine and sodium [1-14C]acetate. The accumulation of radiolabel within unsaturated intermediates (di-, tri- and tetraunsaturated fractions) was low, indicating a rapid formation and derivatisation of these components. Similar results were found for the unsaturated fatty acid fractions of both PE and PG using sodium [1-14C]acetate radiolabel. The regulation of triunsaturated fatty acid components may be a potential control site in PUFA biosynthesis.     

Identification and characterization of Saccharomyces cerevisiae dihydrosphingosine-1-phosphate phosphatase

We have identified the yeast sphingosine resistance gene (YSR2) of Saccharomyces cerevisiae as encoding a protein that specifically dephosphorylates dihydrosphingosine 1-phosphate (DHS-1-P), and we refer to this protein as dihydrosphingosine-1-phosphate phosphatase. Overexpression of YSR2 conferred sphingosine resistance to the dihydrosphingosine-1-P lyase-defective mutant (JS16) of S. cerevisiae, which is hypersensitive to sphingosine. The ysr2Delta deletion mutant of S. cerevisiae accumulated DHS-1-P compared with its wild type strain upon labeling with D-erythro-[4, 5-3H]dihydrosphingosine, whereas overexpression of YSR2 increased dephosphorylation of DHS-1-P. An epitope-tagged fusion protein (YSR2-Flag) was partially purified and found to specifically dephosphorylate DHS-1-P to yield dihydrosphingosine. YSR2 failed to dephosphorylate ceramide 1-phosphate or phosphatidic acid. Functionally, the mutant bearing the ysr2Delta deletion decreased labeling of sphingolipids and increased labeling of glycerolipids dramatically following in vivo labeling with D-erythro-[3H]dihydrosphingosine, but it slightly affected labeling of sphingolipids with inositol. Taken together, these results identify YSR2 as dihydrosphingosine-1-phosphate phosphatase. They also raise the intriguing possibility that phosphorylation followed by dephosphorylation is required for incorporation of exogenous long chain sphingoid bases into sphingolipids.     

An experimental and clinical study of Ossocol, a compound of hydroxylapatite and collagen]

Experiments on white rats revealed that introduction of Ossocol, a sponge with a composition of hydroxyl apatite with collagen, into a removed tooth well prevented mandibular atrophy and was conducive to a more smooth defect filling with better compact bone tissue. Ossocol use in 214 patients with bone tissue defects developing after tooth removal, of odontogenic cysts, sequestra, and after radical surgery for periodontal diseases demonstrated a positive effect of this agent on the course of the postoperative period: the defect was more rapidly replaced by bone tissue. No unfavorable local or general reactions to Ossocol implantation were observed.