Full Blend Research Articles

Spark Plasma co-Sintering of hot work and high speed steel powders for fabrication of a novel tool steel with composite microstructure

The capability to produce a hybrid tool steel with properties that can be modulated on the base of the specific application was investigated. Powder metallurgy (PM) offers the possibility to blend and co-sinter different powders to produce a hybrid material which combines the properties of the base materials. With the aim of producing a new steel with high hardness and good toughness, a hot work tool steel (HWTS) and a high speed steel (HSS) powder were selected. Four blends with different composition (HWTS-HSS: 20%–80%, 40%–60%, 60%–40%, 80%–20%) were produced by spark plasma sintering (SPS) and thermally treated. The influence of composition, particle size distribution and oxygen content was evaluated by the means of density, hardness and apparent fracture toughness of the blends. By selecting powders with a small size and narrow particles size distribution near full dense blends with good mechanical properties can be sintered. Large particles hinder the efficient co-sintering due to the different densification kinetics of the powders. High oxygen content in the base powders does not significantly influences the final density but negatively affects the consolidation process, strongly reducing toughness, particularly of the HWTS.

Identification of Critical Secondary Components of the Sex Pheromone of the Navel Orangeworm (Lepidoptera: Pyralidae)

We identified a four-component sex pheromone blend that is as attractive or more attractive to male navel orangeworm moths, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), than either unmated females or hexane extracts of pheromone glands of females. The blend consisted of (11Z,13Z)-hexadecadienal; (11Z,13Z)-hexadecadien-1-ol; (11Z,13E)-hexadecadien-1-ol; and a hydrocarbon, (3Z,6Z,9Z,12Z,15Z)-tricosapentaene (C23 pentaene), in ratios of approximately 100:100:5:5. Other minor components of pheromone gland extracts included (11Z,13E)-hexadecadienal; (11E,13Z)-hexadecadienal; (11Z,13Z)-hexadecadien-1-yl acetate; (Z)-11-hexadecenal; hexadecanal; hexadecan-1-ol; and a second pentaene, (3Z,6Z,9Z,12Z,15Z)-pentacosapentaene (C25 pentaene). These minor components did not increase attraction of male navel orangeworm to the basic four-component blend. The use of another, cross-attracted pyralid moth, Pyralisfarinalis L., as a model species was crucial in implicating the C23 pentaene as an important component of the navel orangeworm pheromone blend. The four-component navel orangeworm pheromone blend was optimized using a combination of wind tunnel and field bioassays. Attractiveness of field deployed synthetic pheromone lures decreased rapidly despite incorporation of stabilizers and use of different release devices, suggesting that degradation products antagonize male navel orangeworm responses. Overall, the combination of type I lepidopteran pheromone components consisting of C16 aldehydes and alcohols with type II components consisting of long-chain polyunsaturated hydrocarbons has now been documented in several lepidopteran species and may indicate a paradigm shift in the range of compounds that constitute sex pheromone blends for individual lepidopteran species. This suggests that careful reexamination of pheromone gland contents for both type I and type II compounds may prove fruitful in species that have been studied but for which full attractant blends have eluded identification.

Aggregation Pheromone of the Qinghai Spruce Bark Beetle, Ips nitidus Eggers

Volatiles from hindgut extracts of males of the Qinghai spruce bark beetle, Ips nitidus, from different attack phases (phase 1: unpaired males and phases 2-4: males joined with one to three females) and hindgut extracts of mated females were analyzed by gas chromatography-mass spectrometry (GC-MS)/flame ionization detection (FID) with both polar and enantioselective columns. The GC-MS/FID analyses demonstrated that unpaired males from attack phase 1 (nuptial chamber constructed) produced 2-methyl-3-buten-2-ol, approx. 74%-(-)-ipsdienol, and (-)-cis-verbenol as major hindgut components, and (-)-trans-verbenol, (-)-ipsenol, (-)-verbenone, myrtenol, and 2-phenylethanol as minor or trace components. The quantities of 2-methyl-3-buten-2-ol and especially ipsdienol decreased after mating during phases 2-4, whereas the quantities of (-)-cis- and (-)-trans-verbenol did not change. In contrast, the quantity of (-)-ipsenol seemed to increase as mating activity progressed. After mating with three females (harem size = 3; phase 4), only trace to small amounts of male-specific compounds were detected from I. nitidus male hindguts. Chemical analysis of the hindgut extracts of mated females showed only trace amounts of semiochemicals. A field-trapping bioassay in Qinghai, China showed that the four-component "full blend" containing the three major components, 2-methyl-3-buten-2-ol, (+/-)-ipsdienol, and (-)-cis-verbenol, plus a minor component, (-)-trans-verbenol, caught significantly more I. nitidus (male/female = 1:2.2) than did the unbaited control and two binary blends. The replacement of (+/-)-ipsdienol with nearly enantiomerically pure (-)-ipsdienol in the "full blend" significantly reduced trap catches, which suggests that both enantiomers are needed for attraction. On the other hand, removal of (-)-trans-verbenol from the active "full blend" had no significant effect on trap catches. Our results suggest that the three major components, 2-methyl-3-buten-2-ol, 74%-(-)-ipsdienol, and (-)-cis-verbenol (at 7:2:1), produced by unpaired fed males, are likely the aggregation pheromone components of I. nitidus, thus representing the first characterization of an aggregation pheromone system of a bark beetle native solely to China.

Contribution of different constituents to the toxicity of the essential oil constituents of Vernonia amygdalina (Compositae) and Xylopia aetiopica (Annonaceae) on maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

The lethal toxicity of the major constituent of the essential oils of Vernonia amygdalina and Xylopia aetiopica, and of selected blends of these against Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) was compared with those of the full blends of the essential oils. The compounds were assayed in amounts and proportions present in the minimum 100% lethal dose of the essential oils. The major component of X. aetiopica was found to be largely responsible for the toxic action of its essential oil against S. zeamais, On the other hand the toxic action of V. amygdalina was due to the combined effects of its constituents, either with or without significant individual toxic action of their own against the insects. The implication of these results and their implication in screening and using plants and their phytochemicals for S. zeamais control is highlighted.

Predatory Mite Attraction to Herbivore-induced Plant Odors is not a Consequence of Attraction to Individual Herbivore-induced Plant Volatiles

Predatory mites locate herbivorous mites, their prey, by the aid of herbivore-induced plant volatiles (HIPV). These HIPV differ with plant and/or herbivore species, and it is not well understood how predators cope with this variation. We hypothesized that predators are attracted to specific compounds in HIPV, and that they can identify these compounds in odor mixtures not previously experienced. To test this, we assessed the olfactory response of Phytoseiulus persimilis, a predatory mite that preys on the highly polyphagous herbivore Tetranychus urticae. The responses of the predatory mite to a dilution series of each of 30 structurally different compounds were tested. They mites responded to most of these compounds, but usually in an aversive way. Individual HIPV were no more attractive (or less repellent) than out-group compounds, i.e., volatiles not induced in plants fed upon by spider-mites. Only three samples were significantly attractive to the mites: octan-1-ol, not involved in indirect defense, and cis-3-hexen-1-ol and methyl salicylate, which are both induced by herbivory, but not specific for the herbivore that infests the plant. Attraction to individual compounds was low compared to the full HIPV blend from Lima bean. These results indicate that individual HIPV have no a priori meaning to the mites. Hence, there is no reason why they could profit from an ability to identify individual compounds in odor mixtures. Subsequent experiments confirmed that naive predatory mites do not prefer tomato HIPV, which included the attractive compound methyl salicylate, over the odor of an uninfested bean. However, upon associating each of these odors with food over a period of 15 min, both are preferred. The memory to this association wanes within 24 hr. We conclude that P. persimilis possesses a limited ability to identify individual spider mite-induced plant volatiles in odor mixtures. We suggest that predatory mites instead learn to respond to prey-associated mixtures of volatiles and, thus, to odor blends as a whole.

Sex Pheromone of the Plant Bug, Phytocoris calli Knight

Female Phytocoris calli Knight produce a sex pheromone from metathoracic scent glands. The pheromone consists of hexyl acetate (HA; present in both sexes), with the female-specific compounds (E)-2-hexenyl acetate (E2HA), octyl acetate (OA), and (E)-2-octenyl acetate (E2OA). HA and E2OA are key components of the pheromone, since deletion of either ester from the blend resulted in a total suppression of conspecific male trap catches. However, the binary blend of HA and E2OA was only slightly attractive to males, and was significantly less active than the four-component blend. The two ternary blends, HA/OA/E2OA and HA/E2HA/E2OA, were each as attractive as the full four-component blend. Evidence from previous research on the pheromones of Phytocoris species suggests that the apparent chemical redundancy in the pheromone of P. calli may actually be involved in maintaining reproductive isolation from other sympatric species. The patterns observed for pheromones of the five Phytocoris species whose pheromones have been directly (P. californicus, P. relativus, P. difficilis, and P. calli) or indirectly (P. breviusculus) studied are discussed vis-à-vis the pheromone intractable species of Lygus and Lygocoris plant bugs.

EAG and behavioral responses of the wingless tea aphid Toxoptera aurantii (Homoptera: Aphididae) to tea plant volatiles

Electrophysiological and behavioral responses of the wingless tea aphid, Toxoptera aurantii (Boyer), to 14 synthetic volatiles identified from tea shoots, their partial (GLV mixture) and full (ACB mixture) blends, and fresh young tea leaves, buds, tender stems, adult tea leaves and tea aphid-damaged young leaves (ADYL) were studied by using an electroantennography (EAG) and a four-arm olfactometer. ACB elicited the largest EAG responses. Major volatile components, Z-3-hexen-1-ol, E-2-hexenal, n-hexanol, methyl salicylate and benzylalcohol, from the tea shoots were strongly EAG active. All the 4 tested tea shoot tissues also elicited significant EAG responses, with the young tea leaves being the strongest, followed by buds, tender stems and adult tea leaves. Surprisingly, ADYL elicited a weakly negative EAG response. In the olfactory assays, the fresh and tender tea leaves, as well as the individual major volatile components, e.g. Z-3-hexenyl acetate, methyl salicylate, E-2-hexen-1-ol and Z-3-hexen-1-ol, from the tender shoots (EAG-active) were all attractive. This result might indicate that the wingless tea aphids may use tea shoot volatiles as kairomone to find their optimal feeding sites, e.g. fresh tender tea shoots.

Plant volatiles are behavioral cues for adult females of the gall wasp Antistrophus rufus

The purpose of this study was to identify plant volatiles that provide host location cues for adult females of the gall wasp Antistrophus rufus Gillette (Hymenoptera: Cynipidae). Larvae of this species inhabit flowering stems of the prairie perennial Silphium laciniatum L. (Asteraceae). Adult females responded to volatile compounds emitted by stems of S. laciniatum in field olfactometer bioassays. Plant volatiles were monoterpenes, including, in descending order of abundance, racemic α- and β-pinene (~50% “+” enantiomer for both), (+)-limonene, (−)-camphene, and β-myrcene. In laboratory bioassays, females responded to aeration extracts of plant stems, the full blend of synthetic monoterpenes, and the four-component blend of α-pinene, β-pinene, (+)-limonene, and (−)-camphene. This monoterpene blend apparently serves as an olfactory cue for host plant location for female A. rufus and is the first such cue to be reported for a cynipid gall wasp. Species-specific ratios of plant monoterpenes may provide cues for gall wasp females to distinguish between plant species and choose appropriate hosts for oviposition. The olfactometer and bioassay techniques developed for this research may be useful for field bioassays of other types of minute arthropods.

Attractive responses by Monochamus galloprovincialis (Col., Cerambycidae) to host and bark beetle semiochemicals

Abstract: The pine sawyer Monochamus galloprovincialis is the European vector of the recently introduced pine wood nematode. This nematode is the causal organism of pine wilt disease, a serious tree killer in East Asia. Efficacious baits and traps to monitor and control this beetle are now required. The effect of bark beetle (Ips spp.) pheromone components, released individually (ipsenol) or in blends (ipsenol, ipsdienol, cis‐verbenol and methyl‐butenol), together with host volatiles (turpentine or α‐pinene and ethanol) on M. galloprovincialis trap catches has been studied in Spain. A kairomonal response by male and female of M. galloprovincialis to Ips semiochemicals was found. Beetles were more attracted to host blends supplemented with bark beetle pheromones than to host volatiles alone. Ipsenol alone was attractive to pine sawyers, and was synergistic with α‐pinene and ethanol. The full blend of the four Ips semiochemicals and the host compounds was highly attractive. Multiple‐funnel traps were as effective as black cross‐vane traps in capturing this insect when the escape of trapped beetles was prevented. Trapping of non‐target bark beetle predators was also evaluated. The trogossitid Temnochila coerulea and clerid Thanasimus formicarius were kairomonally attracted to and killed in traps baited with bark beetle pheromones. These results suggest that effective monitoring of M. galloprovincialis would be possible by baiting any of these traps with host volatiles and Ips semiochemicals, but reduction of the lure components and trap modification to minimize impact on predators should be considered.

Overview of development of an anti‐attractant based technology for spruce protection against Ips typographus: From past failures to future success

AbstractWe describe a series of experiments on the protection of Norway spruce (Picea abies (L.) Karst.) logs and standing trees against Ips typographus L. (Coleoptera: Scolytidae). The tested protective materials were applied 1) at point sources and 2) area‐covering using zeolite‐based dispensers. We performed 11 terrestrial and one aerial application (using a helicopter) between 1992 and 2001. We gradually replaced polyethylene‐bag verbenone dispensers by composite dispensers releasing verbenone and non‐host volatiles (NHV: green leaf volatiles, trans‐conophthorin, and C8‐alcohols). Many experiments did not give statistically significant results, due to the low number of true replicates and the spatial heterogeneity of beetle attacks. The protection of horizontal objects like logs or lying trees with anti‐attractants was not always successful. In the future, positive results can be expected with an area covering spray applied by zeolite dispensers containing mixtures of verbenone and NHV. A similar approach could probably be used in aerial spraying of anti‐attractants.We have succeeded in our attempt to protect zones of standing spruce trees from I. typographus attacks. We used dispensers with a combination of verbenone and a full blend of NHV compounds. The protection is not complete, but in both 2000 and 2001, the treatment significantly decreased the probability of the insect attack on trees by 60–80 %.

Response of female Cydia molesta (Lepidoptera: Tortricidae) to plant derived volatiles.

Peach shoot volatiles were attractive to mated female oriental fruit moth, Cydia molesta (Busck), in a dual choice arena. No preference was observed between leaf odours from the principle host plant, peach, and the secondary host plant, apple. Twenty-two compounds were identified in headspace volatiles of peach shoots using gas chromatography-mass spectrometry. Green leaf volatiles accounted for more than 50% of the total emitted volatiles. A bioassay-assisted fractionation using different sorbent polymers indicated an attractant effect of compounds with a chain length of 6-8 carbon atoms. The major compounds of this fraction were tested either singly or in combinations for behavioural response of females. Significant bioactivity was found for a three-component mixture of (Z)-3-hexen-1-yl acetate, (Z)-3-hexen-1-ol and benzaldehyde in a 4:1:1 ratio. This synthetic mixture elicited a similar attractant effect as the full natural blend from peach shoots as well as the bioactive fraction.

Blend effects in the toxicity of the essential oil constituents of Ocimum kilimandscharicum and Ocimum kenyense (Labiateae) on two post-harvest insect pests

The lethal toxicity of major components of the essential oils of Ocimum kilimandscharicum and O. kenyense and of selected blends of these against Sitophilus zeamais and Rhyzopertha dominica were compared with those of the full blends of the essential oils. The compounds were assayed in amounts and proportions present in the minimum 100% lethal dose of the oils. Whereas a major component of O. kilimandscharicum was found to be largely responsible for the toxic action of its essential oil against R. dominica, the results with the other treatments indicated that the toxic action of the essential oils were due to the combined effects of different components, either with or without significant individual toxic action of their own against the insects. The significance of the results and their implication in screening and using plants and their phytochemicals for pest and microbial control are highlighted.

The Role of Different Components of the Pheromone Emission of Mature Males of the Desert Locust, Schistocerca Gregaria (Forskål) (Orthoptera: Acrididae) in Accelerating Maturation of Immature Adults

Different blends of five chromatographically prominent components of the pheromone emission of gregarious-phase mature desert locust Schistocerca gregaria (Forskal) (Orthoptera: Acrididae) males were bioassayed for their maturation-accelerating effects on immature counterparts. The blend of all five components, namely anisole, veratrole, benzaldehyde, phenylacetonitrile and 4-vinylveratrole was as effective as the emission from live mature males in accelerating the onset of mating in immature males. Subtraction of anisole had no significant effect but removal of any one of the other four components significantly reduced the acceleration potency of the resulting blends. The maximum reduction occurred in the absence of phenylacetonitrile which appears to be critical to the activity of the blend. The magnitude of reduction in maturation acceleration that resulted from the subtraction of the other three components suggests that, although present in lesser relative amounts, these compounds contribute significantly to the activity of the full blend. Some differences were found between the onset of integumental yellowing and mating which indicate that blends of slightly different compositions are involved in promoting these two physiological processes.

Sex or Food? Appetetive Learning of Sex Odors in a Male Moth

Moths learn to associate a flower odor with a food reward after a few learning trials. Can a hungry, male moth learn to associate a sex attractant with food instead of with sex? We provided a hungry male with odors of single female sex pheromone components, of the full sex pheromone blend or of a flower odor component as cues in an appetitive learning assay. The male learned the single pheromone components just as well as the flower odor. Learning was, however, severely impaired when the full sex pheromone blend was used as conditioning stimulus. The "hard-wiring" between pheromone odor and sex thus seems to be restricted to those circumstances when the male moth experiences the full blend.

Balling behaviour in the honey bee in response to exogenous queen mandibular gland pheromone

SUMMARYHoney bee (Apis mellifera) colonies generally respond to the introduction of a foreign queen by aggressively surrounding or ‘balling’ the new queen. We explored the role of queen mandibular gland pheromone (QMP) in initiating balling behaviour. The addition of a synthetic blend of QMP to the abdomen of worker bees initiated balling behaviour of these workers when re-introduced into their own colony. There was a positive, dose-dependent relationship between the number of balls formed, time to ball formation and size of balls formed. When the QMP dose was below that normally found on a queen, 10−3 queen equivalents, it resulted in significantly slower ball formation and smaller ball diameter. The acid components of the five-component QMP elicited balling behaviour while the aromatic components did not, but the full blend elicited the strongest response. Stinging behaviour was the most prevalent and persistent factor preceding the formation of balls. We concur with others who have proposed that a ‘marking’ pheromone is released when an aggressive worker flexes her abdomen, and that the release of this pheromone causes ball formation. There were no obvious changes in resident queen behaviour while balling of QMP-treated workers was occurring. We conclude that queen mandibular gland pheromone is a significant signal in foreign queen recognition and the initiation of balling behaviour.

Quality assurance/quality control procedures for chlorinated hydrocarbons in human breast adipose tissue.

Extensive literature exists supporting the accumulation of organochlorine pesticides such as DDT [2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane], and polychlorinated biphenyls (PCBs) in human adipose tissue. Debate has surfaced concerning the link between these environmental contaminants and human breast cancer. Accurate residue analysis and proper analytical procedures are critical in determining the extent to which these compounds play a role in human breast cancer. Further, adequate quality assessment/quality control (QA/QC) is critical for reliable residue analysis. The purpose of this research was twofold: (1) to find an appropriate surrogate for human breast adipose tissue for spiking purposes, as human samples are difficult to obtain, and (2) to develop a human breast adipose tissue pool that yields adequate reproducibility with low coefficients of variation (CVs) for each compound of interest. Using a previously validated method developed in the Analytical Laboratory at Colorado State University, rendered ovine adipose tissue was found to be a suitable spiking material, as it was free of interfering compounds and behaved in a manner similar to human breast adipose tissue throughout the analytical method. Further, this analytical method was used to produce data on three control pool preparations: (A) blended human breast adipose tissue (n = 26), (B) blended and partially rendered human breast adipose tissue (n = 12), and (C) fully blended and rendered human breast adipose tissue (n = 15). The CVs between control pools vary up to 20% for a single compound. The most reproducible preparation procedure requires full blending and rendering.

Pheromone-mediated responses of male cabbage looper moths,Trichoplusia ni, following various exposures to sex pheromone or (Z)-7-dodecenol

Prolonged preexposure (three days) of maleTrichoplusia ni to its six-component sex pheromone blend or its major pheromone component, (Z)-7-dodecenyl acetate, reduced subsequent upwind flight responses to a pheromone source. Preexposure to (Z)-7-dodecenol increased upwind flight responses to a pheromone source combined with (Z)-7-dodecenol. The impact of long-term preexposures was moderate when compared to the more immediate effects of background noise. When (Z)-7-dodecenyl acetate was presented as background noise, all maleT. ni failed to respond to a plume of the full pheromone blend. However, most moths succeeded in locking on to the pheromone plume and contacting the pheromone source in the presence of the five minor pheromone components as background noise. When (Z)-7-dodecenol was released as background noise the response rate to a pheromone source containing (Z)-7-dodecenol was increased dramatically. This indicates that males became adapted to (Z)-7-dodecenol while responding to the pheromone source. The results of this study indicate that both long-term preexposure treatments and immediate exposure to background noise can limit the ability of maleT. ni to respond to sex pheromone sources.

The Application of NIR Spectroscopy for the Prediction of Properties of Australian Refined Reformate

A rapid NIR method for the determination of octane number of reformate samples of Australian refined motor gasoline is described. Results of predictions using calibration sets based on ASTM full blends and actual reformate samples are presented. Interpretation of spectral data using principal component analysis facilitates the selection of a suitable analytical spectral range and demonstrates that the reformate samples may be distinguished on the basis of the geographical origins of the parent crude oils. The described method forms a basis for practical application and is a possible alternative to the standard CFR engine test method.

Evaluation of Traps for Apple Maggot (Diptera: Tephritidae) Populations Associated with Cherry and Hawthorn in Utah

The effectiveness of various traps for apple maggot, Rhagoletis pomonella (Walsh) populations associated with cherry and hawthorn in Utah was investigated during the summers of 1987 and 1988. In cherry and hawthorn, unbaited Pherocon AM traps with an external ammonium carbonate lure were significantly better over the entire season than the standard Pherocon AM panels, red spheres (8.5 em diameter), and red spheres baited with the “Fein” blend of apple volatiles (a mixture of hexyl acetate, ( E )-2-hexen-l-yl acetate, butyl 2-methylbutanoate, propyl hexanoate, hexyl propanoate, butyl hexanoate, and hexyl butanoate in 35:2:8:12:5:28:10 ratio). In addition, the standard Pherocon AM traps caught more flies than the red sphere traps in cherry and hawthorn. Results between the two locations in 1987 and the single location in 1988 were similar, even though different host plants and population levels were sampled. In season-long and short-term studies, there were no apparent benefits associated with the use of either the single component butyl hexanoate lure or the full Fein blend of apple volatiles in conjunction with either red spheres or a Ladd trap (a yellow panel 28 by 21.6 cm with 8.5-cm red hemispheres attached to each side). Ladd traps with ammonium carbonate were the best traps under Utah conditions.

Redundancy in a chemical signal: Behavioral responses of maleTrichoplusia ni to a 6-Component sex pheromone blend

The flight response of maleTrichoplusia ni was observed in a flight tunnel to a sex pheromone blend composed of six components:Z7-12∶Ac, 12∶Ac,Z5-12∶Ac, 11-12∶Ac,Z7-14∶Ac, and Z9-14∶Ac. The number of males reaching a 3000-μg source of this blend was > 95%, equal to that observed to female glands and significantly greater than with the previously identified two-component blend (Z7-12∶Ac + 12∶Ac). In subtraction tests, all five-component blends, with the exception of the blend lacking the primary componentZ7-12∶Ac, and several four-component blends elicited similar peak levels of upwind flight, source contacts, and hairpencil displays to that observed with the six-component blend. We characterize the substitution of certain minor components for one another as a form of redundancy in the chemical signal and suggest that it contributes to response specificity and signal recognition in males. The results also support the concept that the full blend of components acts as a unit to influence male behavior at all phases of the response. Individual minor components were not responsible for eliciting specific behaviors in the sequence.