Catalytic, Z-Selective, Semi-Hydrogenation of Alkynes with a Zinc-Anilide Complex.

The reversible activation of dihydrogen with a molecular zinc anilide complex is reported. The mechanism of this reaction has been probed through stoichiometric experiments and density functional theory (DFT) calculations. The combined evidence suggests that H2 activation occurs by addition across the Zn-N bond via a four-membered transition state in which the Zn and N atoms play a dual role of Lewis acid and Lewis base. The zinc hydride complex that results from H2 addition has been shown to be remarkably effective for the hydrozincation of C═C bonds at modest temperatures. The scope of hydrozincation includes alkynes, alkenes, and a 1,3-butadiyne. For alkynes, the hydrozincation step is stereospecific leading exclusively to the syn-isomer. Competition experiments show that the hydrozincation of alkynes is faster than the equivalent alkene substrates. These new discoveries have been used to develop a catalytic system for the semi-hydrogenation of alkynes. The catalytic scope includes both aryl- and alkyl-substituted internal alkynes and proceeds with high alkene: alkane, Z:E ratios, and modest functional group tolerance. This work offers a first example of selective hydrogenation catalysis using zinc complexes.

Effect of Louisiana sweet crude oil on a Pacific coral, Pocillopora damicornis.

Recent oil spill responses such as the Deepwater Horizon event have underscored the need for crude oil ecotoxicological threshold data for shallow water corals to assist in natural resource damage assessments. We determined the toxicity of a mechanically agitated oil-seawater mixture (high-energy water-accommodated fraction, HEWAF) of a sweet crude oil on a branched stony coral, Pocillopora damicornis. We report the results of two experiments: a 96 h static renewal exposure experiment and a "pulse-chase" experiment of three short-term exposure durations followed by a recovery period in artificial seawater. Five endpoints were used to determine ecotoxicological values: 1) algal symbiont chlorophyll fluorescence, 2) a tissue regeneration assay and a visual health metric with three endpoints: 3) tissue integrity, 4) tissue color, and 5) polyp behavior. The sum of 50 entrained polycyclic aromatic hydrocarbons (tPAH50) was used as a proxy for oil exposure. For the 96 h exposure dose response experiment, dark-adapted maximum quantum yield (Fv/Fm) of the dinoflagellate symbionts was least affected by crude oil (EC50 = 913 µg/L tPAH50); light-adapted effective quantum yield (EQY) was more sensitive (EC50 =  428 µg/L tPAH50). In the health assessment, polyp behavior (EC50 = 27 µg/L tPAH50) was more sensitive than tissue integrity (EC50 = 806 µg/L tPAH50) or tissue color (EC50 = 926 µg/L tPAH50). Tissue regeneration proved to be a particularly sensitive measurement for toxicity effects (EC50 = 10 µg/L tPAH50). Short duration (6-24 h) exposures using 503 µg/L tPAH50 (average concentration) resulted in negative impacts to P. damicornis and its symbionts. Recovery of chlorophyll a fluorescence levels for 6-24 h oil exposures was observed in a few hours (Fv/Fm) to several days (EQY) following recovery in fresh seawater. The coral health assessments for tissue integrity and tissue color were not affected following short-term oil exposure durations, but the 96 h treatment duration resulted in significant decreases for both. A reduction in polyp behavior (extension) was observed for all treatment durations, with recovery observed for the short-term (6-24 h) exposures within 1-2 days following placement in fresh seawater. Wounded and intact fragments exposed to oil treatments were particularly sensitive, with significant delays observed in tissue regeneration. Estimating ecotoxicological values for P. damicornis exposed to crude oil HEWAFs provides a basis for natural resource damage assessments for oil spills in reef ecosystems. These data, when combined with ecotoxicological values for other coral reef species, will contribute to the development of species sensitivity models.

Characterizing sources of variability in zebrafish embryo screening protocols.

There is a need for fast, efficient, and cost-effective hazard identification and characterization of chemical hazards. This need is generating increased interest in the use of zebrafish embryos as both a screening tool and an alternative to mammalian test methods. A Collaborative Workshop on Aquatic Models and 21st Century Toxicology identified the lack of appropriate and consistent testing protocols as a challenge to the broader application of the zebrafish embryo model. The National Toxicology Program established the Systematic Evaluation of the Application of Zebrafish in Toxicology (SEAZIT) initiative to address the lack of consistent testing guidelines and identify sources of variability for zebrafish-based assays. This report summarizes initial SEAZIT information-gathering efforts. Investigators in academic, government, and industry laboratories that routinely use zebrafish embryos for chemical toxicity testing were asked about their husbandry practices and standard protocols. Information was collected about protocol components including zebrafish strains, feed, system water, disease surveillance, embryo exposure conditions, and endpoints. Literature was reviewed to assess issues raised by the investigators. Interviews revealed substantial variability across design parameters, data collected, and analysis procedures. The presence of the chorion and renewal of exposure media (static versus static-renewal) were identified as design parameters that could potentially influence study outcomes and should be investigated further with studies to determine chemical uptake from treatment solution into embryos. The information gathered in this effort provides a basis for future SEAZIT activities to promote more consistent practices among researchers using zebrafish embryos for toxicity evaluation.

Is the Combination of Insecticide and Mating Disruption Synergistic or Additive in Lightbrown Apple Moth, Epiphyas postvittana?

Pest suppression from combinations of tactics is fundamental to pest management and eradication. Interactions may occur among tactical combinations and affect suppression. The best case is synergistic, where suppression from a combination is greater than the sum of effects from single tactics (AB >> A+B). We explored how mating disruption and insecticide interacted at field scale, additively or synergistically. Use of a pheromone delivery formulation (SPLAT™) as either a mating disruption treatment (i.e. a two-component pheromone alone) or as a lure and kill treatment (i.e. the two-component pheromone plus a permethrin insecticide) was compared for efficacy against the lightbrown apple moth Epiphyas postvittana. Next, four point-source densities of the SPLAT™ formulations were compared for communication disruption. Finally, the mating disruption and lure and kill treatments were applied with a broadcast insecticide. Population assessment used virgin female traps and synthetic pheromone in replicated 9-ha vineyard plots compared with untreated controls and insecticide-treated plots, to investigate interactions. Lure and kill and mating disruption provided equivalent suppression; no additional benefit accrued from including permethrin with the pheromone suggesting lack of contact. The highest point-source density tested (625/ha) was most effective. The insect growth regulator methoxyfenoxide applied by broadcast application lowered pest prevalence by 70% for the first ten weeks compared to pre-trial. Pheromone addition suppressed the pest further by an estimated 92.5%, for overall suppression of 97.7% from the treatment combination of insecticide plus mating disruption. This was close to that expected for an additive model of interactivity between insecticide and mating disruption (AB = A+B) estimated from plots with single tactics as 98% suppression in a combination. The results indicate the need to examine other tactical combinations to achieve the potential cost-efficiencies of synergistic interactions.

Behavioral Avoidance - Will Physiological Insecticide Resistance Level of Insect Strains Affect Their Oviposition and Movement Responses?

Agricultural organisms, such as insect herbivores, provide unique opportunities for studies of adaptive evolutionary processes, including effects of insecticides on movement and oviposition behavior. In this study, Brassica leaves were treated with one of two non-systemic insecticides and exposed to two individual strains (referred to as single or double resistance) of diamondback moth (Plutella xylostella) (DBM) exhibiting physiological resistance. Behavioral responses by these two strains were compared as part of characterizing the relative effect of levels of physiological resistance on the likelihood of insects showing signs of behavioral avoidance. For each DBM strain, we used choice bioassays to quantify two possible types of behavioral avoidance: 1) females ovipositing predominantly on leaf surfaces without insecticides, and 2) larvae avoiding insecticide-treated leaf surfaces. In three-choice bioassays (leaves with no pesticide, 50% coverage with pesticide, or 100% coverage with pesticide), females from the single resistance DBM strain laid significantly more eggs on water treated leaves compared to leaves with 100% insecticide coverage (both gamma-cyhalothrin and spinetoram). Females from the double resistance DBM strain also laid significantly more eggs on water treated leaves compared to leaves with 100% gamma-cyhalothrin, while moths did not adjust their oviposition behavior in response to spinetoram. Larvae from the single resistance DBM strain showed a significant increase in mobility in response to both insecticides and avoided insecticide-treated portions of leaves when given a choice. On the other hand, DBM larvae from the double resistance strain showed a significant decrease in mobility in response to insecticides, and they did not avoid insecticide-treated portions of leaves when given a choice. Our results suggest that pest populations with physiological resistance may show behavioral avoidance, as resistant females avoided oviposition on leaves without gamma-cyhalothrin. Thus, physiological resistance and behavioral avoidance do not appear to be controlled by the same selection pressures, and the mechanisms responsible for behavioral avoidance may vary among life stages. Our analysis also suggested that a population with lesser physiological resistance to insecticides may be under a stronger selection pressure and therefore be more likely to develop avoidance behaviors than a population with higher levels of physiological resistance.

Clinical Practice Guideline: Chiropractic Care for Low Back Pain.

OBJECTIVE: The purpose of this article is to provide an update of a previously published evidence-based practice guideline on chiropractic management of low back pain. METHODS: This project updated and combined 3 previous guidelines. A systematic review of articles published between October 2009 through February 2014 was conducted to update the literature published since the previous Council on Chiropractic Guidelines and Practice Parameters (CCGPP) guideline was developed. Articles with new relevant information were summarized and provided to the Delphi panel as background information along with the previous CCGPP guidelines. Delphi panelists who served on previous consensus projects and represented a broad sampling of jurisdictions and practice experience related to low back pain management were invited to participate. Thirty-seven panelists participated; 33 were doctors of chiropractic (DCs). In addition, public comment was sought by posting the consensus statements on the CCGPP Web site. The RAND-UCLA methodology was used to reach formal consensus. RESULTS: Consensus was reached after 1 round of revisions, with an additional round conducted to reach consensus on the changes that resulted from the public comment period. Most recommendations made in the original guidelines were unchanged after going through the consensus process. CONCLUSIONS: The evidence supports that doctors of chiropractic are well suited to diagnose, treat, co-manage, and manage the treatment of patients with low back pain disorders.

Determining the drift potential of Venturi nozzles compared with standard nozzles across three insecticide spray solutions in a wind tunnel.

BACKGROUND: Previous research has sought to adopt the use of drift-reducing technologies (DRTs) for use in field trials to control diamondback moth (DBM) Plutella xylostella (L.) (Lepidoptera: Plutellidae) in canola (Brassica napus L.). Previous studies observed no difference in canopy penetration from fine to coarse sprays, but the coverage was higher for fine sprays. DBM has a strong propensity to avoid sprayed plant material, putting further pressure on selecting technologies that maximise coverage, but often this is at the expense of a greater drift potential. This study aims to examine the addition of a DRT oil that is labelled for control of DBM as well and its effect on the drift potential of the spray solution. The objectives of the study are to quantify the droplet size spectrum and spray drift potential of each nozzle type to select technologies that reduce spray drift, to examine the effect of the insecticide tank mix at both (50 and 100 L ha(-1) ) application rates on droplet size and spray drift potential across tested nozzle type and to compare the droplet size results of each nozzle by tank mix against the drift potential of each nozzle. RESULTS: The nozzle type affected the drift potential the most, but the spray solution also affected drift potential. The fine spray quality (TCP) resulted in the greatest drift potential (7.2%), whereas the coarse spray quality (AIXR) resulted in the lowest (1.3%), across all spray solutions. The spray solutions mixed at the 100 L ha(-1) application volume rate resulted in a higher drift potential than the same products mixed at the 50 L ha(-1) mix rate. The addition of the paraffinic DRT oil was significant in reducing the drift potential of Bacillus thuringiensis var. kurstkai (Bt)-only treatments across all tested nozzle types. The reduction in drift potential from the fine spray quality to the coarse spray quality was up to 85%. CONCLUSION: The addition of a DRT oil is an effective way to reduce the spray solution drift potential across all nozzle types and tank mixes evaluated in this study. The greatest reduction in drift potential can be achieved by changing nozzle type, which can reduce the losses of the spray to the surrounding environment. Venturi nozzles greatly reduce the drift potential compared with standard nozzles by as much as 85% across all three insecticide spray solutions. Results suggest that a significant reduction in drift potential can be achieved by changing the nozzle type, and can be achieved without a loss in control of DBM. © 2016 Society of Chemical Industry.

Thermal tolerance limits of diamondback moth in ramping and plunging assays.

Thermal sensitivity is a crucial determinant of insect abundance and distribution. The way it is measured can have a critical influence on the conclusions made. Diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important insect pest of cruciferous crops around the world and the thermal responses of polyphagous species are critical to understand the influences of a rapidly changing climate on their distribution and abundance. Experiments were carried out to the lethal temperature limits (ULT0 and LLT0: temperatures where there is no survival) as well as Upper and Lower Lethal Temperature (ULT25 and LLT25) (temperature where 25% DBM survived) of lab-reared adult DBM population to extreme temperatures attained by either two-way ramping (ramping temperatures from baseline to LT25 and ramping back again) or sudden plunging method. In this study the ULT0 for DBM was recorded as 42.6°C and LLT0 was recorded as -16.5°C. DBM had an ULT25 of 41.8°C and LLT25 of -15.2°C. The duration of exposure to extreme temperatures had significant impacts on survival of DBM, with extreme temperatures and/or longer durations contributing to higher lethality. Comparing the two-way ramping temperature treatment to that of direct plunging temperature treatment, our study clearly demonstrated that DBM was more tolerant to temperature in the two-way ramping assay than that of the plunging assay for cold temperatures, but at warmer temperatures survival exhibited no differences between ramping and plunging. These results suggest that DBM will not be put under physiological stress from a rapidly changing climate, rather access to host plants in marginal habitats has enabled them to expand their distribution. Two-way temperature ramping enhances survival of DBM at cold temperatures, and this needs to be examined across a range of taxa and life stages to determine if enhanced survival is widespread incorporating a ramping recovery method.

From integrated pest management to integrated pest eradication: technologies and future needs.

BACKGROUND: With growing globalization and trade, insect incursions are increasing worldwide. A proportion of incursions involve pests of major economic crops (e.g.Mediterranean fruit fly), conservation value (e.g. tramp ants) or health significance(e.g.mosquitoes), and maybe the targets of eradication programmes. Historically, such responses have included the use of broad spectrum insecticides. However, with increasing public awareness of the negative aspects of pesticides, new environmentally friendly and effective techniques are needed. Here, we review and evaluate a range of selective to broad-spectrum tactical options for suppression which either have, or show potential for, integration within arthropod eradication programmes. RESULTS: Most of the available technologies have their roots in pest management, but higher efficacy is required. Further refinement may be needed for use in eradication. Integration of several tactics is usually needed, as compatible tools can be used simultaneously to target different parts of the pest life cycle. However, not all technologies are fully compatible; for example, the simultaneous use of mass trapping and the sterile insect technique (SIT) may be suboptimal, although sequential application may still be effective. CONCLUSIONS: Broad-spectrum insecticides are generally incompatible with some biologically based technologies such as the SIT, but may be used to reduce the population so that density-dependent tactics can be used. Several novel technologies with fewer nontarget impacts have been proposed in recent years, and need to be properly evaluated for their applicability to insecteradication. Overall, there are still major gaps in surveillance and selective eradication technologies for most insects.

Evaluation of sequential presence-absence sampling plans for the diamondback moth (Plutellidae: Lepidoptera) in cruciferous crops in Australia.

Two sets of sequential presence-absence sampling plans for decision-making in the management of diamondback moth, Plutella xylostella (L.), were developed and evaluated. One set of sampling plans targeted the classification of proportions of infested plants, and the other set of sampling plans targeted the classification of larval density. The action thresholds investigated were 0.15, 0.25, 0.35, and 0.45 proportion of plants infested with larvae, and 0.2, 0.4, 0.6, and 0.8 larvae per plant. They are representative of the action thresholds currently practiced by Australian crucifer growers. For each sampling plan, the population range within which a minimal correct decision rate of 95% can be expected at a maximal average sample size of 50 plants (OC95ASN50) was specified. The closeness of an OC95ASN50 range to the target action threshold is a measure of the expected performance of the sampling plan. A closer distance reflects better performance. The OC95ASN50 ranges of the proportion-classification sampling plans were within 33-53% of the target action thresholds. The width of these OC95ASN50 ranges represents 73-87% of the entire population range (0-1). For the classification of larval density, an empirical proportion-density model was first established using data from different states and different cruciferous crops. The OC95ASN50 ranges of the density-classification sampling plans were within 57-75% of the target action threshold. Simulated sampling of 20 independent data sets showed that for most data sets the correct classification rate was at least 98% and the matching average sample size was <50 plants.

Proximal airway mucous cells of ovalbumin-sensitized and -challenged Brown Norway rats accumulate the neuropeptide calcitonin gene-related peptide.

Mucous cell hypersecretion and increased neuropeptide production play a role in the exacerbation of symptoms associated with asthma. The source of these neuropeptides have been confined to the contributions of small afferent nerves or possibly neuroendocrine cells. We tested the hypothesis that repeated exposure to allergen would alter the sources and abundance of neuropeptides in airways. Right middle lobes from rats (8 wk old) exposed to 2.5% ovalbumin (OVA) for five episodes (30 min each) or filtered air were inflation fixed with paraformaldehyde. The lobes were dissected to expose the airway tree, permeabilized with DMSO, and incubated in antibody to rat calcitonin gene-related peptide (CGRP), followed with a fluorochrome-labeled second antibody. CGRP-positive structures were imaged via confocal microscopy. Airways were later embedded in plastic and sectioned for cell identification. In animals challenged with OVA, CGRP-positive cells, not neuroendocrine or neuronal in origin (confirmed by a lack of protein gene product 9.5 signal), were recorded along the axial path. In section, this fluorescent signal was localized to granules within epithelial cells. Alcian blue/periodic acid-Schiff staining of these same sections positively identify these cells as mucous cells. Mucous cells of animals not challenged with OVA were not positive for CGRP. We conclude that episodic allergen exposure results in the accumulation of CGRP within mucous cells, creating a new source for the release of this neuropeptide within the airway.

Dental malocclusion and upper airway obstruction, an otolaryngologist's perspective.

INTRODUCTION: This paper, through the presentation of eight case reports and a limited literature review, attempts to illustrate the negative effect that upper airway obstruction can have on developing dental occlusion and the positive effect that upper airway relief can have on the 'normalization' of various malocclusion patterns believed to be related to chronic obligate mouth breathing. OBJECTIVE: To study the effect of airway relief (usually through tonsillectomy and/or adenoidectomy) on various patterns of dental malocclusion. METHODS: Children coming to the office of the lead author (D.J.W.) found to be obligate mouth breathers and who also had dental malocclusion had Polaroid 'bite' pictures taken at the time of their initial visit. One year or more after their surgery for upper airway relief (tonsillectomy and adenoidectomy in these cases) a second 'bite' photograph was taken and compared to the first. RESULTS: In all cases selected in this study there was observed improvement in their dental occlusion within a year following surgery to improve their breathing. CONCLUSION: It is the opinion of the authors of this paper that upper airway obstruction may have a negative effect on the developing transitional dental occlusion and that eliminating the cause of upper airway obstruction can lead to 'normalization' of occlusion in such children. Further orthodontic corrective modalities may be required for optimal occlusal results.