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Abstract: In this study, we investigated the influence of semantic and perceptual learning on the perception of odor blending mixtures, i.e., mixtures eliciting a different odor quality as compared with their components. Following a between-groups design, we set out to examine whether being pre-exposed to target mixture odor labels (semantic learning) and to the mixture’s odor components (perceptual olfactory learning) would modify the perception of odor mixtures quality. In a first experimental condition, a group (control) of 28 subjects evaluated the odor quality of mixtures and then their components. In this condition, subjects were not exposed to the individual odor components (no perceptual learning) and were only weakly exposed to the target mixture odor labels (weak semantic learning) when asked to evaluate the quality of the mixtures. In a second experimental condition, a group (learning) of 29 other subjects performed the same tasks but evaluated first the components and then the mixtures. In this condition, subjects have experienced both perceptual and strong semantic learning when asked to evaluate the quality of the mixtures. Within each condition, odor quality was evaluated following two verbal tasks: a free description task and a choice between several odor attributes. The comparison of the data obtained in both experimental conditions revealed that semantic and perceptual learning could influence odor mixture quality and suggested a differential influence of both learning types according to mixture complexity.

Objective To determine whether there is an association between early recurrent miscarriage (before 10 weeks of pregnancy) and Factor V Leiden and G20210A prothrombin mutations.

A simplified particle-size fractionation procedure of soil organic matter was used to localize and quantify the non-extractable residues of $^{14}$ C-labelled isoproturon in a soil where large amounts of bound residues were formed. Four size-fractions were isolated corresponding to non-humified organic matter in fractions ($> 200$ and $200-50$ $\mu$ m) and humified organic matter in fractions ( $50-0.2 \mu$ m and $< 0.2$ $\mu$ m). The majority of $^{14}$ C-isoproturon bound residues were associated with humified organic matter. In each fraction, concentrations of bound residues normalized to carbon (C) content were used as indicators of the capacity of organic matter to bind herbicide residues. Binding capacities differed among size fractions, and were greater for the more decomposed organic materials located in fractions $< 50$ $\mu$ m. Results were compared to previous data concerning atrazine residues and discussed in terms of the physico-chemical and microbial processes implicated in the binding properties of the different fractions.

PROBLEM: Fas antigen (APO‐1/CD95) can regulate the activity of various cells during adulthood. This study aimed at determining whether Fas may also be involved in the regulation of very early events such as the embryo preimplantation stage.
 METHOD OF STUDY: We used mouse embryo stem (ES) cell line as a model for testing the effect of Fas crosslinking upon anti‐Fas monoclonal antibody (MoAb) treatment. In addition, this treatment was also applied to in‐vitromouse‐embryo culture.
 RESULTS: Flow‐cytometry analysis of cultured ES cells demonstrated an increase in Fas expression, unchanged in the presence of mouse interleukin‐2, while greatly upregulated in the presence of lipopolysaccharide (LPS). As determined by various means, ES cells may undergo a Fas‐mediated apoptosis, slightly but significantly intensified by the addition of LPS to cell cultures. We also report that anti‐Fas MoAb directly inhibited two‐cell stage mouse‐embryo (preimplantation) development in in‐vitroculture conditions.
 CONCLUSION: These data suggest a novel mechanism controlling the regulation of physiological cell turnover as well as blastocyst implantation in early embryo development.

Interactions between flavour compounds and polysaccharides have been studied by exclusion size chromatography, the Hummel and Dreyer method. Hydrogen bonding was found between 2-acetyl thia-zole and dextrines of different degrees of polymerisation. The number of binding sites and the affinity constant increase by increasing the degree of polymerisation. Hydrogen bonding was also responsible for the interactions between xanthane and 1-octen-3-ol or 2-acetyl pyra-zine, with 1 mole of 1-octen-3-ol bound per pentasaccharide repeating unit. Unfortunately, the number of flavour compounds, which can be studied with this method, is limited due to their low water solubility and their low UV absorption.

Zusammenfassung Die Synthese der Enantiomeren des Sotolons (2), einer Aromaleitsubstanz für Flor-Sherryund Botrytis-Weine, wird aufgezeigt und das chromatographische Verhalten der Enantiomeren (R)-2 und (S)-2 an permethyliertemß-Cyclodextrin bestimmt. Mittels enantioselektiver multidimensionaler Gaschromatographie (Säulenkombination: DB 1701/Permethyl-ß-Cyclodextrin) werden die Enantiomerenverhältnisse der chiralen?-Lactone Pantolacton (1), Sotolon (2), Soleron (3) und 4-Carbethoxy-4-hydroxybutyrolactone (4) in Flor-Sherry- und Botrytis-Weinen ermittelt. Während für die Lactone1 und4 hohe Enantiomerenüberschüsse zugunsten der (4R)-konfigurierten Spiegelbildisomere nachgewiesen werden, können aus dem für Soleron (3) bzw. Sotolon (2) ermittelten Enantiomerenverhältnissen keine Rückschlüsse auf die Authentizität dieser Verbindungen abgeleitet werden.

An alternative to the traditional solvent extraction method used to extract and rapidly quantify ethyl-and vinylphenol and ethyl-and vinylgaiacol from wine is presented. The method is based on retention of volatile phenols on adsorbants. Among the tested resins, the most efficient, AG 2-X8 (anion exchange resin), worked as well with a synthetic solution as with wines. The percolation of clarified wine adjusted to pH 9 on this resin permits, in particular, the elimination of organic acids. Phenols are not eluted after rinsing the column with 1N HCl, but are eluted with methanol after this treatment. Good recovery (91 %) and good repeatability are observed. The eluate is directly analysed by HPLC on an RP18 column after two-fold dilution in water. The four volatile phenols were completely separated and detected by UV at 280 nm with high sensitivity (20–40 ppb). No interference with other compounds were noted in the different wines analysed.

Zusammenfassung 153 flüchtige Verbindungen wurden in einem Dichlormethanextrakt aus Erdbeermarmelade bestimmt. Die Identifizierung der Aromastoffe erfolgte mittels HRGC-MS und Vergleich der spektroskopischen und chromatographischen Daten mit Referenzverbindungen. Die Hauptkomponenten des Aromas von Erdbeermarmelade stellen Mesifuran, 1-(2-Furanyl)-2-hydroxyethanon sowie verschiedene Säuren, Alkohole und Ester dar. Das Aroma von Erdbeermarmelade zeichnet sich im Vergleich zum Aroma der Frucht durch einen erhöhten Gehalt an Furfural und 2-Acetylfuran aus. Während ca. zwei Drittel der flüchtigen Bestandteile von Erdbeermarmelade aus der Frucht stammen, sind 1-(2-Furanyl)-2-hydroxyethanon und drei unbekannte „Nerolidol-oxide“ charakteristische Aromakomponenten der Marmelade. Maillard-Reaktionsprodukte wie 5-Hydroxymethyl-2-furaldehyd und 2,3-Dihydro-3,5-dihydroxy-6-me-thyl-4H-pyran-4-on kommen in Marmelade in nur relativ geringen Konzentrationen vor.

Ten tomato varieties, i.e. Cencara, Daniella, Elena, Ibiza, Lemon Boy, Lucy, Melody, Perfecto, Raf and Rondello, were studied over two consecutive years by GC and GC-sniffing for their differences in flavour composition. Precautions were taken to avoid differences due to the growth conditions and stage of matu-rity. The aroma profiles obtained from dilutions of the extracts confirm the importance of most compounds previously reported as being key flavour compounds in tomatoes. Moreover, they outline a greater number of other key compounds which had not been identified or reported as such in the literature. Among them, 2-methoxyphenol, eugenol, decanal and geranylacetone were identified. Among 39 compounds quantified, 27 were found to permit discrimination between varieties both in 1992 and 1993. Six varieties were characterised in both years by specific flavour compositions. The differences between varieties is due to particular relative amounts of volatile compounds arising from the metabolism of aliphatic amino acids and carotenoids. Volatile compounds arising from each metabolic processes were found to be highly correlated with each other.

Combined electrophysiological recordings (EAG) and gas chromatographic separation were performed in order to investigate which volatile chemical components of a sunflower extract could be detected by honeybee workers and thus are likely to trigger the foraging behavior. A direct coupling device allowed for the stimulation of the antennal receptors with individual constituents of a polar fraction of the flower aroma shown to be attractive to bees. More than 100 compounds were separated from the extract. Twenty-four compounds elicited clear EAG responses. These compounds were identified by mass spectrometry (electronic impact and chemical ionisation). Both short- and long-chain aliphatic alcohols, one short-chain aliphatic aldehyde, one acid, two esters, and terpenic compounds were found to stimulate the antennal receptors. Six compounds identified in previous behavioral experiments were found to exhibit EAG activity. The chemicals screened by this method may be used for recognition of the plant odor and the selective behavior of honeybees.

We used chemosensitive and chemoresistant variants of the neoplastic mouse MXT mammary and human J82 and T24 bladder cell lines to characterize verapamil-induced cell proliferation and morphonuclear modifications in drug-treated and untreated cells. Chemoresistance to vinorelbine (Navelbine, aVinca alkaloid derivative), to DIAM3 (an investigational alkylating compound) and to Adriamycin (an intercalating agent) in the presence or absence of verapamil was monitored by means of the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results showed that verapamil restored a significant level of chemosensitivity in doses such as 1 µM or 10 µM in the three chemoresistant variants. The digital cell image analysis of Feulgen-stained T24-resistant cell nuclei revealed that verapamil restored the drug-treated cell kinetics and morphonuclear features observed in the sensitive counterpart especially with respect to the effects of adriamycin. Interestingly, verapamil induced a highly significant chromatin decondensation in resistant but not in sensitive variants. Such verapamil-induced decondensation may favour the accessibility of drugs to their DNA targets. Therefore, in addition to the well-known action of the drug on the influx of a cytotoxic compound from the cellular to the intracellular compartment, verapamil might also favour the accessibility of the nucleus, to the drug.

FPLC purification of mouse monoclonal anti-human IgE antibody xb6-16 showed 2 major peaks of different molecular weight, peak 1 (>106 d) and peak 3 (1.6×105 d). Peak 1 consisted of IgG 1 and IgM, peak 3 of IgG 1 only. On a protein weight basis, peak 1 was 100 times more potent than peak 3 in inducing histamine release from human basophils. Preincubation of peak 3 with anti-IgG 1 enhanced the mediator release triggered by this fraction. On this basis, the potentiating effect of aggregated IgG 1 or IgG 1-IgM complexes on mediator release from basophils is discussed.

Strict anaerobic conditions and the production of methane have been demonstrated in the proctodeum in larvae ofOryctes nasicornisL., a xylophagous coleopteran. In ruminants, the breakdown of cellulose by extracellular symbiotic organisms is complete and leads to the formation of by-products which may act as substrates for methanogenic bacteria.