Search results for "ethyl"

Conifer Needles as Thermoplastic Composite Fillers: Structure and Properties

2016

This study describes the properties of thermoplastic polymer composites based on polyethylene (of low and high density) and ethylene-propylene copolymers using various types of conifer needles (pine, spruce, fir, and cedar) as fillers. For the needles, thermogravimetric analysis (TGA) and TGA/Fourier transform infrared spectroscopy (TGA/FTIR) were performed to investigate their structures and thermal resistance, as required for the composite processing methods. Moreover, structural differences were studied for the analyzed fillers and composite materials (FTIR). The results were compared with the values obtained for composites with conifer wood flour. Composites with conifer needles (pine) …

Species diversity of larval parasitoids of the European grapevine moth (Lobesia botrana, Lepidoptera: Tortricidae): the influence of region and culti…

2010

7 pages; International audience; The European grapevine moth, Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae) is a major pest of grapevines responsible for great economic losses and frequent insecticide applications. Nevertheless, the use of parasitoids as potential biological control agents has received very little attention. In this study, we present results from a survey on parasitoid species collected from French and Swiss vineyards over a period of 2 years. Over 2000 larvae of L. botrana were collected from six grape cultivars out of which a total of 118 parasitoids emerged. Ten species were identified. Exochus notatus (Holmgren, 1858) (Hymenoptera: Ichneumoni…

2-methylthiazolidine and 4-ethylguaiacol, male sex pheromone components of the cockroach Nauphoeta cinerea (Dictyoptera, Bladeridae) : A reinvestigat…

1992

49 ref.; International audience; In Nauphoeta cinerea, male calling behavior is associated with sex pheromone release by the sternal glands. The male pheromone that attracts females from a distance is a mixture of 2-methylthiazolidine and 4-ethylguaiacol. It is active at very low concentrations, 0.05 and 0.01 ng, respectively. Two other compounds, 3-hydroxy-2-butanone and 2-methyl-2thiazoline, act at close range, keeping the female in the vicinity of the male. The function of the volatile pheromone and those of previously described contact pheromones are discussed in regard to their possible involvement in the establishment of male dominant-subordinate relationships.

Medium-size droplets of methyl ricinoleate are reduced by cell-surface activity in the gamma-decalactone production by Yarrowia lipolytica.

2000

International audience; Size of methyl ricinoleate droplets during biotransformation into gamma-decalactone by Yarrowia lipolytica was measured in both homogenized and non-homogenized media. In non-homogenized but shaken medium, droplets had an average volume surface diameter d32 of 2.5 microm whereas it was 0.7 microm in homogenized and shaken medium. But as soon as yeast cells were inoculated, both diameters became similar at about 0.7 microm and did not vary significantly until the end of the culture. The growth of Y. lipolytica in both media was very similar except for the lag phase which was lowered in homogenized medium conditions.

Phytotoxicity and metabolism of chlortoluron in two wheat varieties

1985

Abstract Varietal susceptibility of winter wheat to chlortoluron, 1-(3-chloro-4-methylphenyl)-3,3 dimethylurea, has been studied in two varieties, Corin (susceptible) and Clement (tolerant). After a 24-hr root absorption of the herbicide, phytotoxicity was estimated from growth measurements. When administered at 12 to 96 μM concentrations, the herbicide reduced the growth of both varieties. A significant selective effect was found at 96 μM. Measurements of chlorophyll fluorescence-induction kinetics allowed to discriminate between the two varieties treated with 12 to 48 μM chlortoluron. The metabolism of chlortoluron was studied following absorption of 24 μM solutions. Both varieties produc…

Lures for red palm weevil trapping systems: aggregation pheromone and synthetic kairomone

2016

Background The optimisation of the lure is essential for the implementation of trapping systems to control insect pests. In this work, the response of the red palm weevil (RPW), Rhynchophorus ferrugineus Olivier, to increasing emission rates of its aggregation pheromone (ferrugineol) and the efficacy of a convenient synthetic kairomone based on fermentation odours (ethyl acetate and ethanol) have been evaluated in different years and locations along the Mediterranean basin. Results In general, although capture data and emission had noticeable variability among locations, significantly fewer RPW were captured in pyramidal Picusan® traps with the lowest ferrugineol emission rates tested (0.6-…

2021

Centaurothamnus maximus (family Asteraceae), is a leafy shrub indigenous to the southwestern Arabian Peninsula. With a paucity of phytochemical data on this species, we set out to chemically characterize the plant. From the aerial parts, two newly identified guaianolides were isolated: 3β-hydroxy-4α(acetoxy)-4β(hydroxymethyl)-8α-(4-hydroxy methacrylate)-1αH,5αH, 6αH-gual-10(14),11(13)-dien-6,12-olide (1) and 15-descarboxy picrolide A (2). Seven previously reported compounds were also isolated: 3β, 4α, 8α-trihydroxy-4-(hydroxymethyl)-lαH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6,12-olide (3), chlorohyssopifolin B (4), cynaropikrin (5), hydroxyjanerin (6), chlorojanerin (7), isorhamnetin (8), …

Influence of pulsed electric field processing on the quality of fruit juice beverages sweetened with Stevia rebaudiana

2017

Abstract A fruit juice-stevia beverage was processed using pulsed electric fields (PEF), a non-thermal preservation technology, with the purpose of investigating the feasibility of PEF for bioactive compounds and steviol glycosides enhancement and its impact on physicochemical properties. Variable ranges of response surface methodology were 20–40 kV/cm (electric field strength), 100–360 μs (treatment time) and 0–2.5% (w/v) stevia. After PEF, ascorbic acid was retained by more than 74%. Some of the analyzed PEF treatments resulted in an enhancement of total anthocyanins and carotenoids. The best results for rebaudioside A/stevioside ratio were obtained when PEF was applied at 30 kV/cm for 23…

Essential oil variability in a collection of Ocimum basilicum L. (basil) cultivars.

2016

Ocimum basilicum L. (Lamiaceae) is an aromatic plant of great tradition in the Mediterranean area. Its economic importance is growing up determining an expansion of cultivation. This paper evaluated the morphological traits, the chemical profiles, and antibacterial activity of 21 cultivars of basil belonging to Ê»Genoveseʼ, Ê»Napoletanoʼ, and Ê»Purple basilʼ types. The cultivars were characterized by different growth rate and morphological traits. The chemical composition of the oils analyzed by GC and GC/MS analysis, supported by the PCA analysis, underlined the strong influence of chemotype. It is noteworthy that estragole, never present in Genovese and purple basil types, occurred in …

Firming of fruit tissues by vacuum infusion of pectin methylesterase: Visualisation of enzyme action

2008

 ; Apple pieces were vacuum-impregnated with either a pectin methylesterase (PME) and calcium solution or with water prior to pasteurization. Pasteurized apple pieces impregnated with PME and calcium showed a significantly higher firmness. Moreover, solid state C-13 NMR spectroscopy of apple cell wall residues revealed an increase of their molecular rigidity. Exogenous PME addition involved a decrease from 82% to 45% of apple pectin degree of methyl-esterification. Microscopic observations of apple slices immunolabelled with antibodies specific for pectins showed that (i) demethyl-esterification was more intense in the cell wall region lining intercellular spaces (demonstrating a key role f…