Pre‐necking and post‐necking relaxation and creep behavior of polycarbonate: A phenomenological study

Experiments have been performed to investigate the mechanical response of unfilled polycarbonate vis‐à‐vis the influence of prior deformation on stress relaxation and creep. Piecewise linear deformation histories, which involve strain‐controlled tensile loading of a specimen to a maximum load and partial unloading to a target strain/stress point as prologue to a relaxation test, have been shown to qualitatively influence the recorded stress‐time behavior. In particular, the stress magnitude during relaxation first increases and is then followed by a decrease. Analogously, in creep tests during unloading, the strain might decrease and then increase. Time characteristics for this U‐turn in the deformation response are influenced by the placement of the test. The influence of prior specimen conditioning on this phenomenon is investigated by comparing test data from virgin samples to that of specimens having high (～85%) inelastic strain from prior tensile elongation. Findings suggest that the observed persistence in the occurrence of this reversal effect for both types of specimens is evidence of the need to incorporate this behavior into the fold of material modeling. Additionally, this novel relaxation and creep behavior has been observed in other amorphous (poly(phenylene oxide)) and crystalline (high‐density polyethylene) polymers. Polym. Eng. Sci. 44:1783–1791, 2004. © 2004 Society of Plastics Engineers.     

Synergistic Sex Pheromone Components of White-Spotted Tussock Moth, Orgyia thyellina

In 1996, the exotic white-spotted tussock moth (WSTM), Orgyia thyellina (Lepidoptera: Lymantriidae), was discovered in Auckland, New Zealand. Because establishment of WSTM would threaten New Zealand's orchard industry and international trade, eradication of WSTM with microbial insecticide was initiated. To monitor and complement eradication of WSTM by capture of male moths in pheromone-baited traps, pheromone components of female WSTM needed to be identified. Coupled gas chromatographic–electroantennographic detection analysis of pheromone gland extract revealed several compounds that elicited responses from male moth antennae. Mass spectra of the two most EAD-active compounds suggested, and comparative GC-MS of authentic standards confirmed, that they were (Z)-6-heneicosen-11-one (Z6–11-one) and (Z)-6-heneicosen-9-one, the latter termed here thyellinone. In field experiments in Japan, Z6–11-one plus thyellinone at a 100:5 ratio attracted WSTM males, whereas either ketone alone failed to attract a single male moth. Addition of further candidate pheromone components did not enhance attractiveness of the binary blend. Through the 1997–1998 summer, 45,000 commercial trap lures baited with 2000 g of Z6–11-one and 100 g of thyellinone were deployed in Auckland towards eradication of the residual WSTM population.Dedicated to my dear mother in honor of her 75th birthday     

Decadienoates: Sex Pheromone Components of Nettle Caterpillars Darna trima and D. bradleyi

This study was undertaken to identify sex pheromone components of nettle caterpillars Darna trima and Darna bradleyi (Lepidoptera: Limacodidae) whose larvae defoliate oil palm, Elaeis guineensis, in southeast Asia. Coupled gas chromatographic–electroantennographic detection (GCEAD) analyses of pheromone gland extracts revealed two antennally active compounds produced by female D. trima and two by female D. bradleyi. Molecular structures of these candidate pheromone components were identified by electron-impact and chemical-ionization mass spectrometry; retention-index calculations on DB-5, DB-23, and DB-210 columns; microanalytical treatments, as well as syntheses of "auxilliary" compounds that facilitated identification of the compounds. The compounds from D. trima were 2-methylbutyl (E)-7,9-decadienoate (A) and (E)-2-hexenyl (E)-7,9decadienoate (B); from D. bradleyi we identified methyl (E)-7,9-decadienoate (C), and isobutyl (E)-7,9-decadienoate (D). In field experiments in Malaysia, (S)-2-methylbutyl (E)-7,9-decadienoate (SA) in combination with B proved to be essential and synergistic pheromone components for attraction of male D. trima. (R)-2-Methylbutyl (E)-7,9-decadienoate (RA) had no behavioral activity. Compound D singly attracted male D. bradleyi, but addition of C to D at a 1 : 10 ratio significantly enhanced attractiveness of the bait. Synthetic pheromone blends were more effective trap baits than unmated female moths and could be developed for monitoring populations of D. trima and D. bradleyi in Asian oil palm plantations.     

(<Emphasis Type="Italic">Z,Z</Emphasis>)-6,9-Heneicosadien-11-One: Major Sex Pheromone Component Of Painted Apple Moth, <Emphasis Type="Italic">Teia anartoides</Emphasis>

(Z, Z)-6,9-Heneicosadien-11-one (Z6Z9-11-one-21Hy) was identified as the major sex pheromone component of the painted apple moth (PAM), Teia anartoides (Lepidoptera: Lymantriidae), on the basis of (1) comparative gas chromatographic-electroantennographic detection (GC-EAD) analyses, GC-mass spectrometry (MS), high-performance liquid chromatography (HPLC)-MS, and HPLC-UV/visible spectroscopy of pheromone gland extracts and authentic standards; (2) GC-EAD analyses of effluvia of calling females; and (3) wind tunnel and field trapping experiments with a synthetic standard. In field experiments in Australia, synthetic Z6Z9-11-one-21Hy as a single component attracted male moths. Wind tunnel experiments suggested that a 4-component blend consisting of Z6Z9-11-one-21Hy, (6Z,9R,10S)-cis-9,10-epoxy-heneicosene (Z6-9R10S-epo-21Hy), (E, E)-7,9-heneicosadien-6,11-dione (E7E9-6,11-dione-21Hy), and 6-hydroxy-(E, E)-7,9-heneicosadien-11-one (E7E9-6-ol-11-one-21Hy) (all present in pheromone gland extracts) might induce more males to orient toward, approach, and contact the source than did Z6Z9-11-one-21Hy as a single component. Additional experiments are needed to determine conclusively whether or not Z6-9R10S-epo-21Hy, E7E9-6,11-dione-21Hy, and E7E9-6-ol-11-one-21Hy might be minor sex pheromone components of PAM. Moreover, attractiveness of synthetic pheromone and virgin PAM females needs to be compared to determine whether synthetic pheromone could replace PAM females as trap baits in the program to monitor eradication of exotic PAM in New Zealand.     

Sex phermone components of mulberry looper,Hemerophila atrilineata butler (lepidoptera: Geometridae)

(6Z-9S, 10R)-Epoxy-octadecene (SR-1) and (3Z, 6Z-9S, 10R)-epoxy-octadecadiene (SR-2) are sex pheromone components of the mulberry looper (MBL),Hemerophila atrilineata Butler. Compounds extracted from female MBL pheromone glands were identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometry. In field experiments in China,SR-2,RS-2, or both combined were hardly attractive, butSR-2 in combination withSR-1 attracted significant numbers of MBL males. Synergistic behavioral activity ofSR-1 plusSR-2, but not of corresponding antipode mixtures, indicates enantiospecificity of MBL pheromone communication. Because blends of racemic and enantiospecific (SR)1 plus2 were similarly attractive, racemic1 plus2 may have potential for mass trapping or confusion of MBL males in commercial mulberry plantations.     

Manufacturing processes of Atlantic Bronze Age annular gold ornaments—A case study of the Guînes gold hard (Pas-de-Calais,France)

ABSTRACT

The gold work from the Western European Middle and Late Bronze Age (about 1500–700 BC) is characterized by solid ornaments and vessels. This article deals with manufacturing techniques of heavy gold jewelry by presenting a gold hoard found at Guînes, Pas-de-Calais, in Northern France, as a case study. In particular, three ornament types will be taken into consideration: (1) solid penannular neck and arm-rings, plain or with linear or geometric decoration; (2) flange-twisted ornaments that appear in different dimensions, as small as ear rings, as neck rings, up to the large size of a belt; (3) complex, composite ornaments. The technological aspects dealt with in this precious metal working context are manifold, including ingot and lost wax casting, hammering and bending of solid rods, the production of flange-twisted rods, chasing as decoration method, and finally joining techniques such as soldering, riveting and folding, and creasing.     

Chirality of synergistic sex pheromone components of the western hemlock looperLambdina fiscellaria lugubrosa (HULST) (Lepidoptera: Geometridae)

Bakers' yeast reduction of (2E)-3-(2-furanyl)-2-methyl-2-propenal yielded the synthetic intermediate, (2S)-3-(2-furanyl)-2-methylpropanol, of high chiral purity (>97% ee) for the synthesis of the enantiomers of 2,5-dimethylheptadecane and 7-methylheptadecane, two synergistic sex pheromone components of the western hemlock looper (WHL),Lambdina fiscellaria lugubrosa Hulst. In electrophysiological bioassays, (7S)- but not (7R)-7-methylheptadecane elicited strong antennal responses by male WHL antennae. In field trapping experiments, addition of (7S)- but not (7R)-7-methylheptadecane to (5R,11S)-5,11-dimethylheptadecane, the major sex pheromone component of WHL, increased attraction. Attraction to (5R,11S)-5,11-dimethylheptadecane in combination with (7S)-7-methyiheptadecane was further enhanced by the addition of (5S)- but not (5R)-2,5-dimethylheptadecane. Similarly, attraction to (5R,11S)-5,11-dimethylheptadecane combined with (5S)-2,5-dimethylheptadecane increased when 7S- but not (7R)-7-methylheptadecane was added as a third component. We conclude that (7S)-7-methylheptadecane and (5S)-2,5-dimethylheptadecane are the synergistic sex pheromone components of WHL. The synthetic methodology described is applicable to the synthesis of chiral methyl-branched pheromones in other orders of the Insecta, particularly Coleoptera, Diptera and Orthoptera.     

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Ethik in der Medizin - Die prospektive Analyse der ethischen Implikationen medizinisch-technischer Innovationen läuft immer auch Gefahr, sich in den Wunschbildern von Marketingexperten zu...     

Opportunities for plant-derived enhancers for iron,zinc, and calcium bioavailability: A review

Understanding of the mechanism of interactions between dietary elements, their salts, and complexing/binding ligands is vital to manage both deficiency and toxicity associated with essential element bioavailability. Numerous mineral ligands are found in both animal and plant foods and are known to exert bioactivity via element chelation resulting in modulation of antioxidant capacity or micobiome metabolism among other physiological outcomes. However, little is explored in the context of dietary mineral ligands and element bioavailability enhancement, particularly with respect to ligands from plant-derived food sources. This review highlights a novel perspective to consider various plant macro/micronutrients as prospective bioavailability enhancing ligands of three essential elements (Fe, Zn, and Ca). We also delineate the molecular mechanisms of the ligand-binding interactions underlying mineral bioaccessibility at the luminal level. We conclude that despite current understandings of some of the structure–activity relationships associated with strong mineral–ligand binding, the physiological links between ligands as element carriers and uptake at targeted sites throughout the gastrointestinal (GI) tract still require more research. The binding behavior of potential ligands in the human diet should be further elucidated and validated using pharmacokinetic approaches and GI models.