bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue-Specific Actions of the Ept1, Ept2, Ept6, and Ept9 Genetic Determinants of Responsiveness to Estrogens in the Female Rat
Authors: Kurz Scott G. , Hansen Kimberly K. , McLaughlin Mac T. , Shivaswamy Vijay , Schaffer Beverly S. , Gould Karen A. , McComb Rodney D. , Meza Jane L. , Shull James D.
Published: April 2008

Ept1, Ept2, Ept6, and Ept9 are quantitative trait loci mapped in crosses between the ACI and Copenhagen (COP) rat strains as genetic determinants of responsiveness of the pituitary gland to estrogens. We have developed four congenic rat strains, each of which carries, on the genetic background of the ACI rat strain, alleles from the COP rat strain that span one of these quantitative trait loci. Relative to the female ACI rats, female ACI.COP-Ept1 rats exhibited reduced responsiveness to 17β-estradiol (E2) in the pituitary gland, as evidenced by quantification of pituitary mass and circulating prolactin, and in the mammary gland, as evidenced by reduced susceptibility to E2-induced mammary cancer. The ACI.COP-Ept2 rat strain exhibited reduced responsiveness to E2 in the pituitary gland but did not differ from the ACI strain in regard to susceptibility to E2-induced mammary cancer. Interestingly, female Ept2 congenic rats exhibited increased responsiveness to E2 in the thymus, as evidenced by enhanced thymic atrophy. The ACI.COP-Ept6 rat strain exhibited increased responsiveness to E2 in the pituitary gland, which was associated with a qualitative phenotype suggestive of enhanced pituitary vascularization. The ACI.COP-Ept9 rat strain exhibited reduced responsiveness to E2 in the anterior pituitary gland, relative to the ACI rat strain. Neither Ept6 nor Ept9 impacted responsiveness to E2 in the mammary gland or thymus. These data indicate that each of these Ept genetic determinants of estrogen action is unique in regard to the tissues in which it exerts its effects and/or the direction of its effect on estrogen responsiveness.
Behavioral and neural responses of juvenile crayfish to moving shadows
Authors: Liden William H. , Herberholz Jens
Published: April 2008

One of the most important decisions any animal has to make is how to respond to sensory cues that suggest an imminent attack by a predator. We measured behavioral and neural responses of juvenile crayfish to moving shadows of different velocities while the animals were searching for food. In all experiments, and independent of shadow velocity, each crayfish produced one of two discrete behavioral outputs: it either tail-flipped backwards by rapid flexion of its abdomen or it immediately stopped its forward locomotion. The probability of each behavioral response was dependent on the velocity of the shadows that were presented. While most animals responded with tail-flips to slow-moving shadows and stops were rarely observed, the number of tail-flips decreased as shadow velocity increased. Tail-flips were almost absent for very fast-moving shadows and stopping behavior became the dominating response. By using a non-invasive technique to record neural activity, we were able to identify the underlying neural circuit that controlled the observed tail-flips. All tail-flips were mediated by activation of the medial giant neurons, which are part of a hardwired neural circuit previously described to produce reflexive responses to tactile stimulation.
Control of shell colour changes in the lobster, Panulirus cygnus
Authors: Wade Nicholas M. , Melville-Smith Roy , Degnan Bernard M. , Hall Michael R.
Published: April 2008

The transition from juvenile to adult in the Australian western rock lobster, Panulirus cygnus (George), is preceded by a mass migration from inshore nursery reefs to offshore breeding grounds. Associated with this migration is a moult which results in the animals that are due to migrate undergoing characteristic colour change from deep red to pale pink, known as the `white' phase, which is believed to be triggered by environmental factors. To investigate this phenomenon, the colour change of wild-caught animals was measured over two separate years in response to two important modifiers of crustacean shell colour, dietary carotenoid and background substrate colour. Changes in shell colour during this colour transition period were influenced more greatly by other factors independent of diet or background substrate and no mass colour change was induced during this time. Shell colour measurement and carotenoid quantification confirmed the presence of animals similar to wild-caught `whites', regardless of the treatment. From these experimental observations we infer that the `white' phase of the western rock lobster is not triggered by dietary modification or in response to background substrate. We propose that this transition is under the regulation of an ontogenetic program activated at a specific moult, which induces presently unidentified molecular changes linked to shell colour production. This unique colour transition may have evolved to provide protective camouflage during migration,and serves as an excellent model to study the genetic mechanisms underlying crustacean shell colouration. These data also provide insight into the changes in carotenoid levels induced by environmental factors, and the ability to modify crustacean shell colour in aquaculture.
Is there life in the horny layer? Dihydropyridine and ryanodine receptors in the skin of female and male chickens (Gallus domesticus)
Authors: Peltonen Liisa M. , Mänttäri Satu
Published: April 2008

Previous findings in pigeons and chickens show that Ca2+ may be accumulated inside the cornified skin cells and that Ca2+microenvironments with a lower- or higher-than-blood concentration may exist in the skin. It has been suggested that the skin may function as a secretory pathway or a reservoir for Ca2+ recycling. To test this hypothesis,we studied the dermis and epidermis of female and male chickens in vivo to find out whether cellular mechanisms exist for the accumulation,recycling or secretion of Ca2+. For calcium influx and intracellular Ca2+ release, respectively, the density of dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs) was examined,using high-affinity (–)-enantiomers of dihydropyridine and ryanodine labelled with fluorophores. To investigate Ca2+ utilization in the skin, the systemic and local activity of the enzyme alkaline phosphatase (ALP)and the concentration of ionic Ca2+ were measured in plasma and in cutaneous extracellular fluid, collected by suction blister technique. We found that both DHPRs and RyRs were present in all skin layers from dermis to horny layer. However, receptor densities were highest in the surface layers. With a basic calcium-rich diet, receptor densities were higher in males,particularly in the dermis and mid-epidermis. After a reduction in the nutritional Ca2+ input, receptor densities in males decreased to the same level as in females, in which the receptor densities were not affected by the amount of Ca2+ in the diet or that resulting from coming out of lay. The extracellular concentration of ionic Ca2+per se was not found to affect the density of DHPRs and RyRs in the skin. Spatially, RyRs seem to be located in the periphery of the sebokeratinocyte. ALP activity was shown to be lower in the extracellular fluid than in the plasma in both sexes. However, activity in both extracellular domains increased significantly in females that had come out of lay. This was probably connected with the increased osteoblast activity related to the reformation of structural bone. In conclusion,voltage-sensitive L-type Ca2+ channels for ion influx and RyRs for Ca2+ release are present in the cells of the skin of female and male chickens. Higher densities in the males receiving excessive Ca2+ imply an increased capacity for Ca2+ influx and intracellular processing. Even though the functional interactions between DHPRs and RyRs in the sebokeratinocytes could not be demonstrated, peripheral colocation and high receptor densities at the level of exocytosis of the lamellar bodies point to their role as part of a signalling pathway for secretion. The finding that DHPRs and RyRs are present in the horny layer implies that the function of the outermost skin might be more active than had been previously thought and that this function might be both secretory and sensory.
The pyloric neural circuit of the herbivorous crabPugettia productashows limited sensitivity to several neuromodulators that elicit robust effects in more opportunistically feeding decapods
Authors: Dickinson Patsy S. , Stemmler Elizabeth A. , Christie Andrew E.
Published: April 2008

Modulation of neural circuits in the crustacean stomatogastric nervous system (STNS) allows flexibility in the movements of the foregut musculature. The extensive repertoire of such resulting motor patterns in dietary generalists is hypothesized to permit these animals to process varied foods. The foregut and STNS of Pugettia producta are similar to those of other decapods, but its diet is more uniform, consisting primarily of kelp. We investigated the distribution of highly conserved neuromodulators in the stomatogastric ganglion (STG) and neuroendocrine organs of Pugettia,and documented their effects on its pyloric rhythm. Using immunohistochemistry, we found that the distributions of Cancer borealis tachykinin-related peptide I (CabTRP I), crustacean cardioactive peptide (CCAP), proctolin, red pigment concentrating hormone (RPCH) and tyrosine hydroxylase (dopamine) were similar to those of other decapods. For all peptides except proctolin, the isoforms responsible for the immunoreactivity were confirmed by mass spectrometry to be the authentic peptides. Only two modulators had physiological effects on the pyloric circuit similar to those seen in other species. In non-rhythmic preparations,proctolin and the muscarinic acetylcholine agonist oxotremorine consistently initiated a full pyloric rhythm. Dopamine usually activated a pyloric rhythm,but this pattern was highly variable. In only about 25% of preparations, RPCH activated a pyloric rhythm similar to that seen in other species. CCAP and CabTRP I had no effect on the pyloric rhythm. Thus, whereas Pugettiapossesses all the neuromodulators investigated, its pyloric rhythm, when compared with other decapods, appears less sensitive to many of them, perhaps because of its limited diet.
Moving Closer to the Action: Examining Compensation Design Effects on Firm Risk
Authors: Devers Cynthia E. , McNamara Gerry , Wiseman Robert M. , Arrfelt Mathias
Published: April 2008

We examine the influence of CEO equity-based compensation on strategic risk taking by the firm. Building off the Behavioral Agency Model, Agency Theory, and Prospect Theory, we develop arguments about when equity-based compensation elements will increase or decrease executive risk propensity and, in turn, strategic risk taking. Incorporating a behavioral perspective into our models of incentive alignment provides us with new and potentially more accurate predictions about how individual elements of CEO pay will influence risk selection, as well as how equity compensation interacts with cash compensation and with other factors to influence risk preferences. In general, this study provides evidence that CEO equity-based compensation significantly influences strategic risk, but that this influence is more nuanced and complex than conventional treatments of executive compensation assume. In particular, we find that different forms of equity-based pay exhibit dissimilar influences on strategic risk and that their influence changes as their value and vesting status change. Second, we find that cash-based forms of pay moderate the incentive properties of equity-based pay, indicating that cash-based pay may affect how executives perceive risks associated with equity pay. Finally, we find that stock price volatility and board actions each also moderate the incentive effects of equity-based pay. In sum, our results argue for increased recognition of a behavioral perspective on executive compensation and greater precision in how we measure and model the incentive alignment properties of CEO compensation.
Application of the Small-Punch Test to Irradiated Reactor Vessel Steels in the Brittle-Ductile Transition Region
Authors: Linse T. , Kuna M. , Schuhknecht J. , Viehrig H.-W.
Published: April 2008

In this paper, a method is applied for the identification of hardening parameters in the brittle-ductile transition region and the determination of Weibull parameters in the brittle region using small-punch tests. A small-punch-test device is developed to measure the load-displacement curve for non-irradiated and irradiated specimens of a reactor vessel steel at different temperatures inside a hot cell. In a global optimization algorithm for the identification of hardening properties, time-consuming finite element method (FEM) calculations are avoided by using neural networks that were trained with the help of a database previously generated by FEM. Identified material properties are compared with data from tensile tests, where available. The influence of irradiation and temperature on the material and fracture behavior is analyzed.
Framework for Predicting Stress Corrosion Cracking
Authors: Staehle RW
Published: April 2008

A method for predicting SCC performance is described involving the corrosion based design approach (CBDA) and the locations for analysis matrix (LAM). This method provides bases for considering all the factors that contribute to corrosion-related failure in an orderly framework. The CBDA includes the steps of environmental definition, material definition, mode definition, superposition, failure definition, statistical definition, accelerated testing, prediction, monitoring and feedback, and fix. The LAM is a matrix that applies to a specific subcomponent and provides a framework for explicit actions for each mode of corrosion at each location where conditions are the most aggressive.
Deterministic Prediction of Localized Corrosion Damage in Power Plant Coolant Circuits
Authors: Macdonald DD , Engelhardt GR
Published: April 2008

The accumulation of damage due to localized corrosion [pitting, stress corrosion cracking (SCC), corrosion fatigue (CF), crevice corrosion (CC), and erosion-corrosion (EC)] in complex industrial systems, such as power plants, refineries, desalination systems, etc., poses a threat to continued safe and economic operation, primarily because of the sudden, catastrophic nature of the resulting failures. Of particular interest in managing these forms of damage is the development of robust algorithms that can be used to predict the integrated damage as a function of time and as a function of the operating conditions of the system. Because complex systems of the same design rapidly become unique, due to differences in operating histories, and because failures are rare events, there is generally insufficient data available on any given system to derive reliable empirical models that capture the impact of all (or even some) of the important independent variables. Accordingly, the models should be, to the greatest extent possible, deterministic with the output being constrained by the natural laws. In this paper, the theory of the initiation of damage, in the form of pitting, is briefly outlined. We then describe the deterministic prediction of the accumulation of damage from SCC and CF in Type 304 SS components in the primary coolant circuits of Boiling Water (Nuclear) Reactors (BWRs) and from pitting and SCC in low-pressure steam turbine disks. These cases have been selected to illustrate the various phases through which localized corrosion damage occurs.
Prediction of Conditions Leading to Stress Corrosion Cracking of Gas Transmission Lines
Authors: Sridhar N , Dunn DS , Anderko A
Published: April 2008

Corrosion, including stress corrosion cracking (SCC), constitutes about 12% of the failures of gas transmission lines. Two types of SCC have been observed: intergranular SCC (IGSCC) under alkaline conditions and transgranular SCC (TGSCC) under near-neutral conditions. The environmental and electrochemical conditions under which these types of SCC can be produced in the laboratory have been reasonably well established. However, a quantitative relationship between the laboratory environments in which SCC can be reproducibly observed and the chemistry of trapped water under disbonded coatings has not been established. The purpose of this paper is to review the state of knowledge of the environmental conditions leading to either type of SCC and relate this to the evolution of the actual environment under disbonded coating. The relationship between SCC and chemistry of trapped water is examined through the use of a comprehensive thermodynamic model. The temporal and spatial evolution of the trapped water chemistry is examined as a function of external conditions through the use of a reactive-transport model.
Effects of Environmental Factors and Potential on Stress Corrosion Cracking of Fe-Ni-Cr-Mo Alloys in Chloride Solutions
Authors: Pan YM , Dunn DS , Cragnolino GA
Published: April 2008

The stress corrosion cracking (SCC) susceptibility of several Fe-Ni-Cr-Mo alloys, which are candidate materials for high-level radioactive waste containers, was evaluated using slow strain rate and fracture mechanics testing. Slow strain rate tests of type 316L stainless steel (SS) and alloy 825 were performed in hot, concentrated chloride solutions (6.2 to 14.0 molal Cl-). SCC of type 316L SS was observed at chloride concentrations equal to or greater than 7.2 molal and temperatures above 95°C, whereas, alloy 825 experienced SCC only in a 14.0 molal Cl− solution at 120 °C. In both materials, SCC does not occur at potentials below the repassivation potential for pitting corrosion (Erp). In fracture mechanics tests using wedge-loaded specimens, alloy 22 was found to be resistant to SCC when tested in 14.0 molal Cl- solutions at 110°C. On the contrary, crack growth was observed in type 316L SS specimens exposed to concentrated chloride solutions at potentials above the Erp. These results suggest that Erp constitutes a lower limit for the critical potential for SCC that can be used for assessing material performance.
Improvement of Stress Corrosion Cracking (SCC) Resistance by Cyclic Pre-Straining in FCC Materials
Authors: de Curiere I , Bayle B , Magnin T
Published: April 2008

Improving the materials resistance to SCC has become a topic of wide interest for theoretical, engineering and financial reasons. The aim of this paper is to propose a process to delay the SCC damage. Recent studies of 316L austenitic stainless steel in boiling MgCl2 solutions show an improvement in SCC resistance by cyclic pre-straining in low cycle fatigue [1]. This improvement consists of an increase in both strain to failure and crack initiation strain, during Slow Strain Rate Tensile (SSRT) tests in aqueous solution.

This paper analyses the effect of pre-fatigue in 316L and copper on their mechanical and electrochemical responses to better understand the delay of SCC damage in boiling MgCl2 and nitrite, respectively.

The explanation for this beneficial effect is related to a modification of both surface electrochemical reactions kinetics and corrosion/plasticity interactions at the crack tip, due to the particular fatigue dislocation structure.
The Use of Atomic Force Microscopy to Detect Nucleation Sites of Stress Corrosion Cracking in Type 304 Stainless Steel
Authors: Brongers MPH , Koch GH , Agrawal AK
Published: April 2008

The nucleation of intergranular stress-corrosion cracking (IGSCC) in Type 304 stainless steel was investigated using atomic force microscopy (AFM). A new test technique with an AFM fluid cell and a miniature specimen bending device was used for the in-situ measurements. It was found that upon plastic deformation of the annealed and sensitized stainless steel slip lines piled up at the grain boundaries. As a result of the increased localized stresses, some of the grain boundaries opened, particularly at grain boundary triple points and grain boundary — twin boundary intersections. These openings were typically 1 to 2 μm wide and about 1 μm deep. After exposure of the specimens to an aqueous 1000 ppm sodium thiosulfate solution small cracks (< 1 grain diameter) formed from the opened sites within a few hours of the exposure. This indicated that the opened triple points act as nucleation sites for the cracks.
An Electrochemical Film-Rupture Model for SCC of Mild Steel in Phosphate Environment
Authors: Raicheff R , Maldonado L
Published: April 2008

The stress-corrosion cracking of mild steel (0.17% C) in phosphate media (0.1 - 2.0M NaH2PO4 at pH = 4 and 20 - 80 °C) is studied using slow strain rate and potential sweep techniques as well as SEM, X-ray diffraction and Mossbauer analysis of the surface films. It is shown that the susceptibility of the steel to SCC depends on the phosphate concentration and it decreases markedly with increase of temperature; the highest SCC susceptibility is observed in the region of active to passive transition of the steel (−0.3 - 0.0 V, SCE). It is established that the films formed at potentials in SCC zone are mixed oxide-phosphates composed by Fe3(PO4)2.8H2O, Fe3(PO4)2.4H2O, FePO4.xH2O and Fe3O4, while the film formed in the passive region (outside SCC zone) is oxide in nature and consists of γ-Fe2O3. It is suggested that SCC may be related to the formation of secondary amorphous iron (III) phosphates in the surface film. An electrochemical model for crack propagation, based on the film rupture concept in SCC and quantitative electrochemical kinetics considerations, and relating the rate of crack propagation with the electrochemical parameters of both metal dissolution and cathodic reactions at the crack tip and outer metal surface is presented. It is shown that the model could be used for calculating the crack propagation rate and defining electrochemical conditions favorable for SCC.
Cyclic Strain Cracking of Stainless Steels in Hot Steam-Hydrocarbon Reformer Condensates: Test Method Development
Authors: Dean SW , Maldonado JG , Kane RD
Published: April 2008

The discovery of a severely cracked mixing tee in the process gas cooling section of a hydrogen plant showed a form of cracking that appeared to have features typical of both fatigue and chloride stress corrosion cracking of 304L stainless steel. However, the conditions were significantly less severe than what would be anticipated for either process alone. It was speculated that a synergism between these processes occurred causing this failure. A laboratory program was undertaken that confirmed that cracking could occur in environments with as little as 1 ppm chloride and 1 ppm NaSCN when both cyclic stressing and anodic polarization were present. Conventional slow strain rate tests on 304L stainless steel in this environment with anodic polarization did not cause environmentally assisted cracking confirming the importance of cyclic stressing. Similar cyclic tests on duplex stainless steel 2205 and nickel alloy 625 did not show cracking regardless of the applied potential up to 600 mV versus Ag/AgCl reference electrode.
Premature Failures of Copper Alloy Valves and Fittings in the New York City Water Supply System
Authors: Andersen GA
Published: April 2008

Copper alloys are used in various water main components in The New York City Water Supply System. Three copper alloys have been found to fail prematurely. Two manganese bronzes, Copper Development Association (CDA) alloys C86500 and C86300, have previously [1] been found to fail in valves and shaft caps as well as nut fasteners in transgranular and intergranular stress corrosion cracking (SCC) modes, respectively.

A valve stem, made of alloy C86500, has just recently been found to fail what appears to be from SCC, but in a combination of transgranular and intergranular modes. Tapping goose necks, and a pressure regular stem made of CDA alloy C83600, have been found to fail prematurely. Failure analyses of the goose necks and the pressure valve stem have been performed; they appear to have failed from SCC with the lead reacting with water. The lead may create an environmental health problem by being absorbed by the potable water and supplied to the buildings they are serving. To corroborate the aforementioned failure analyses, specimens made of alloy C86500 and C83600 were machined from a valve stem and a goose neck respectively and tested in a laboratory with simulated environments. This paper presents the case histories of the two SCC type failures and what action is being taken to remedy these problems.
Stress Corrosion Cracking of Linepipe Steels in Near-Neutral pH Environment: A Review of the Effects of Stress
Authors: Zheng W , Sutherby R , Revie RW , Tyson WR , Shen G
Published: April 2008

Stress corrosion cracking (SCC), a form of environment-assisted cracking, has caused 24 major pipeline failures in the Canadian oil and gas pipeline system. The role of stress in the SCC of linepipe steels in near-neutral pH environment, as in other SCC systems, is complex. In this paper, the effects of stress on the development of both axial cracking and circumferential cracking are reviewed. The long-term beneficial effect of compressive stress introduced by hydrostatic testing is also discussed.
Potential Implications of Inappropriate Assumption Selection on Environmental Modelling Results: An RBCA Case Study
Authors: Sigal EA , Ferguson GM , Bacigalupo CM , Willis RD , Marshall L
Published: April 2008

In the past decade, the field of environmental risk assessment has seen vast improvements in the technologies and tools available to aid with quantification of human health and ecological risks. The development of publicly-available computational modelling tools, such as those based upon the risk based corrective action (RBCA) framework, have allowed those with a potentially less sophisticated understanding of the scientific rationale, equations and methodologies used to simulate environmental fate, toxicology and risk characterization processes to conduct and complete multimedia environmental risk assessments for regulatory approval. However, in many cases, this lack of understanding may result in the selection of inappropriate parameter data (i.e., chemical-, receptor-, or scenario-specific data), unknowingly increasing the uncertainty inherent within the overall assessment of potential risk. Accordingly, the use of inappropriate assumptions and parameters can result in an increase or decrease in the estimated risk, with significant implications on remediation costs or, more importantly, human or environmental health. Three case studies will be presented to illustrate the importance surrounding the selection of appropriate data input parameters, and the potential implications of this selection process on the results of an environmental risk assessment.
A Probabilistic Analysis to Determine Ecological Risk Drivers
Authors: Johnston RK , Munns WR , Nacci DE
Published: April 2008

A probabilistic analysis of exposure and effect data was used to identify chemicals most likely responsible for ecological risk. The mean and standard deviation of the natural log-transformed chemical data were used to estimate the probability of exposure for an area of concern and a reference area. Benchmarks of chemical effects were selected from criteria, standards, and toxicological thresholds in the literature and dose-response models developed for Pb were used to estimate the probability of an effect from Pb. Ecological risk, defined as the probability of exceeding a benchmark or causing an effect given the probability of exposure was calculated for the area of concern and reference area. The probability of an effect from Pb and probability of exceeding any combination of benchmarks were determined by Monte Carlo simulations. Chemicals that caused an incremental increase of risk ⩾ 0.05 above the reference area were identified as potential “risk drivers.”
Harmonization of Test Methods Between the U.S. EPA (OPPTS) and the Organization for Economic Cooperation and Development (OECD): General Overview of Recent Activities with Emphasis on Aquatic and Sediment Methods
Authors: Smrchek JC , Zeeman Maurice
Published: April 2008

A description of ecological effects harmonization activities occurring since 1990, within the U.S. EPA's Office of Prevention, Pesticides, and Toxic Substances (OPPTS), and occurring between OPPTS and OECD was presented at the ASTM Eighth Symposium on Environmental Toxicology and Risk Assessment in 1998. This presentation was subsequently published (Smrchek and Morcock 1999). Recently, there has been a great increase in harmonization activities between OPPTS and OECD. Many additional activities are currently ongoing in five test method areas: physical chemical properties (e.g., Kow methods), effects on biotic systems (ecological effects, e.g., Lemna growth inhibition, covered elsewhere), fate (degradation and accumulation, e.g., aerobic and anaerobic biodegradation), health effects, and in special activities such as in method development and testing of endocrine disruptors (e.g., avian reproduction, fish whole life cycle). The goal remains as before: to harmonize OPPTS guidelines (eventually to be published final as parts 810–885 in volume 40 of the U.S. Code of Federal Regulations) and test guidance with OECD so as to avoid unnecessary and duplicative testing of those chemicals marketed on a world wide basis, to increase efficiency, save test animals, and to reduce nontariff barriers to trade. The latest harmonization activities and results achieved, with a specific emphasis on aquatic and sediment methods are presented. ASTM has played and must continue to play an important part in the U.S. role in the development of these OECD tests. Recent activities include revision of OECD Test Guideline No. 202, Daphnia sp., Acute Immobilisation Test; development of a new oligochaete reproduction test; two chironomid sediment tests (spiked water and spiked sediment); an oligochaete bioaccumulation test; and a guidance document on Aquatic Toxicity Testing of Difficult Substances and Mixtures. Challenges and potential problems for effective harmonization continue to be present. These can be categorized into internal within the U.S. EPA and external to the agency. The former include having adequate available resources, redistribution and changes in workloads to accommodate OECD work, continual education to demonstrate the advantages of harmonization, and obtaining continued support in an environment of budget constraints. External aspects include challenges from the public, the problem of incurring continuing harmonization costs by U.S. industry, accommodating voluntary standards organizations such as ASTM, and difficulties in developing a “U.S. position” on OECD test guidelines. There also continue to be difficulties (not unexpected) in coordination, communication, and cooperation in expert panels and among participating OECD member countries. Several principles for effective harmonization in updating existing OECD test guidelines or in developing new test guidelines are discussed.
The Influence of Four Types of Water on Seedling Emergence and Growth of Barley and the Toxic Interaction with Copper Sulfate
Authors: Stephenson GL , Feisthauer NC , Koper N , McCann JH , Scroggins RP
Published: April 2008

One aspect of the development and validation of terrestrial plant toxicity test methods is to determine the influence of the type of water that is used to irrigate test plants on emergence and seedling growth, and on the toxicity of contaminants in soil. Acute screening and definitive plant seedling emergence and growth tests were conducted with barley in artificial soil. Seedlings were irrigated with tap, well, or deionized water, or a nutrient solution. The influence of water type was similar for both the acute screening and definitive plant tests. No effect of water type on seedling emergence was observed. Shoot growth was greater in barley watered with nutrient solution, but no difference was observed among other water types. Root length was not affected. Root mass was greater when plants were watered with the nutrient solution, but only if compared to plants watered with deionized water. Definitive plant toxicity tests that assessed the toxicity of copper sulfate to barley were conducted. Plants were irrigated with a nutrient solution or tap water. The toxicity of copper sulfate to seedling emergence was affected by water type. Copper sulfate was more toxic to barley when seedlings were watered with the nutrient solution. These results indicate that the type of water used to irrigate terrestrial test plants can influence contaminant toxicity and must be considered when generating or interpreting data.
Comparison of Short- and Long-Term Assays to Detect Toxicity of Anthracene to a Luminescent Bacteria
Authors: El-Alawi YS , Dixon DG , Greenberg BM
Published: April 2008

Anthracene (ANT) toxicity increases significantly after exposure to simulated or natural sunlight. A simple, rapid method for monitoring the photoinduced short- and long-term toxicity of ANT and other PAHs has been developed. The assay is based on changes in the luminescence intensity and growth rate of Vibrio fischeri. Under suitable conditions, V. fischeri emits a constant amount of light as a metabolic by-product. After exposure to a toxicant, the light intensity can be diminished by an amount which is often proportional to the extent of toxicant impact. Generally, V. fischeri has been used in short-term (15–30 min) assays. However, this does not reveal the toxicity of all hazardous chemicals. In particular, we found ANT is not highly toxic in short-term (e.g. 15 minute) assays. As well, the prevalent phototoxicity of this compound was not revealed in a short-term assay. A long-term (e.g. 18 hour) test was developed that assesses the photoinduced toxicity of ANT.
Occurrence and Toxicity of Photomodified Polycyclic Aromatic Hydrocarbon Mixtures Present in Contaminated Sediments
Authors: Lampi MA , El-Alawi YS , McConkey BJ , Huang XD , Dixon DG , Greenberg BM
Published: April 2008

Exposure of PAHs to solar radiation results in the generation of oxygenated products. Many of these oxyPAHs are more toxic and/or carcinogenic than the parent compounds. Environmental photomodification of PAHs could result in formation of toxic compounds not anticipated by regulatory agencies. We have confirmed the presence of oxyPAHs at toxic levels in sediment samples taken from a known contaminated site. Contaminated sediment samples were taken from Hamilton Harbour (Hamilton, Ontario). A reference site from the harbour, known to be free of contaminants was also analyzed. High performance liquid chromatography (HPLC) was used to fractionate, and analyze individual compounds present. Fractions were tested for toxicity using both short-term, and long-term assays on the bacterium Vibrio fischeri.OxyPAHs were found in sediments at concentrations comparable to intact PAHs. Testing confirmed toxicity in fractions containing oxyPAHs on the order of intact PAH-containing fractions. It is concluded that environmental photomodification of PAHs contributes to the presence of toxic compounds that are not properly addressed by current regulations in the U.S. and Canada.
If Not Recovery, Then What?
Authors: Landis WG , McLaughlin JF
Published: April 2008

Recovery of ecological systems is an often-stated goal of activities associated with Superfund sites, toxic spills, and the restoration of habitats such as the Florida Everglades. Often recovery is associated with constructs related to ecosystem health, integrity, or sustainability. Return to an original state has been demonstrated empirically not to be an option. Integrity and sustainability are not defined in a quantitative fashion amenable to prediction. We present two alternative quantitative descriptions of the goals of restoration activities. The first uses surveys of supposedly unimpacted sites to define a multivariate description of the expected community given the specifications of the abiotic factors. The second uses stakeholder-desired characteristics of an ecological system to define the desired ranges for various ecosystem functions and/or structural characteristics and to form an assessment space. With these approaches, a risk assessment can determine the stressors causing the displacement of the system and management options to return to the assessment space. Management goals and actions can be directed at those variables and monitoring programs can be established to measure progress. Assessments about system status relate directly to the properties of concern and the management goals. The methodology does permit the reconstruction of important resources and other valued components of ecological systems.
Chemical Descriptors - An Approach to Codify the EPA Inerts Exempt List (40 CFR 180.1001)
Authors: Magin RW
Published: April 2008

The Adjuvants and Inerts Committee (AIC) of the Chemical Producers and Distributors Association (CPDA) has, in cooperation with the EPA Office of Pesticide Programs (OPP) Inerts group, undertaken a project to codify the inert list. The AIC approach is to combine similar chemicals into families and develop a common chemical descriptor for the family along with CAS numbers. The result is a searchable database that provides an easy and time saving way to identify inerts. Examples are presented of the chemical families identifited and descriptors proposed.
Physical Properties and Use of Branched Alcohol Ethoxylates in Agricultural Formulations
Authors: Elsik CM , Lewis DC , Champion DH , Ashrawi SS
Published: April 2008

Many groups of nonionic surfactants, such as alkylphenol ethoxylates, linear alcohol ethoxylates, sorbitan derivatives and block copolymers have been used as tank mix adjuvants and in pesticide formulations. These surfactants are widely used in spreader-sticker-wetter type adjuvants, and crop oil emulsifiers. The selection of surfactant is based on cost, efficacy and phytotoxicity. A relatively unexplored group of branched C12 alcohol (DDA) ethoxylates offers exceptional wetting performance with relatively low phytotoxicity. The physical and surface properties important to the selection of a surfactant for use in a formulation indicate that the DDA ethoxylates would also be good candidates for use as emulsifiers in Emulsifiable Concentrate (EC) and in Microemulsion (ME) products.
The Use of a Fire-Resistant Turbine Lubricant: Europe Looks to the Future
Authors: Phillips WD
Published: April 2008

Turbine oil fires continue to cause concern. Although not frequent occurrences, a serious fire can have an enormous financial impact. To reduce the risk of hydraulic oil fires in steam turbines, phosphate esters are now widely used, but large volumes of inflammable mineral oil remain in the lubrication system. In order to decrease the fire risk still further, phosphates have also been used in both steam and gas turbines as fire-resistant lubricants. This paper reviews the need for these products and the experience in both trials and commercial operation. It examines the reasons for their slow adoption by industry but also why current market pressures, particularly in Europe, are likely to accelerate their use.
Advanced High-Temperature Air Force Turbine Engine Oil Program
Authors: Gschwender LJ , Snyder CE , Nelson L , Fultz GW , Saba CS
Published: April 2008

Military and commercial jet aircraft engines operate hotter than in the past to increase fuel efficiency. Also, advanced structural engine materials permit hotter burning, more efficient engines. These trends are expected to continue. Many current gas turbine engines experience oil system coking and other problems related to the limited thermal and oxidative stability of the conventional, ester-based gas turbine engine oils. This is because most engines operate on gas turbine oils limited to 150°C. The best current oils have a maximum operating temperature of about 200°C. We initiated a program to develop a new class of ester-based lubricants to meet current and future high-temperature requirements. The target temperature range of this new oil is −40°C to 232°C. Target requirements were established and communicated to industry. This paper presents those requirements and initial results on the most promising candidates.
Improved Response of Turbine Oils Based on Group II Hydrocracked Base Oils Compared with Those Based on Solvent Refined Base Oils
Authors: Schwager BP , Hardy BJ , Aguilar GA
Published: April 2008

Modern industrial equipment makes increasingly severe demands on the lubricating oils used to keep the equipment running. Higher operating temperatures, smaller oil reservoirs, and decreased downtime all help create a severe environment for the lubricant. In response, base oil manufacturers have developed new technology to provide more saturated, high-performance base oils using catalytic hydrocracking technology. Lubricants based on these base oils and properly matched with the right additive technology have longer oxidation life, less deposit forming tendencies, and overall higher performance than solvent refined products.

In this paper, the performance properties of lubricants based on hydrocracked Group II base oils are compared with those of more traditional products based on solvent refined base stocks. Laboratory tests such as the Rotating Pressure Vessel Oxidation Test (ASTM D2272), the Turbine Oil Oxidation Stability Test (ASTM D943), and the Water Separability Test (ASTM D1401) were used to predict performance. The lubricants tested were all from the general category of rust and oxidation inhibited oils (R&O oils), and included turbine oils. In some cases, actual performance was verified in field trials. The data presented confirm the performance advantages of a properly formulated lubricant based on Group II hydrocracked stocks.
Analysis of Isocyanates with LC-MS/MS
Authors: Östin A , Sundgren M , Lindahl R , Ekman J , Levin JO
Published: April 2008

Air sampling of isocyanates with 2-MP coated filters is a well-established method where the isocyanate derivative is analyzed by HPLC with combined UV/electrochemical detection. We have investigated the possibility to use HPLC with tandem mass spectrometry (LC-MS/MS) for detection and quantification with enhanced selectivity and sensitivity. Qualitative analysis of 2-MP derivatized diisocyanates was performed with full scan and the spectra contained a protonated molecule with a dominant fragment containing the 2-MP derivative. The same fragmentation was obtained in the daughter ion spectra from the molecular ion and was selected as target for selected reaction monitoring (SRM). Linear detection with SRM was obtained between 5 pg and 5 ng injected amount. Corresponding LC-UV analysis is in our laboratory performed in a range of 300 pg - 30 ng injected amount. The signal to noise ratio in LC-MS/MS from 50 pg is ranging from 10 – 200 depending on which of the diisocyanates that is analysed. Ten times that amount (500 pg) analyzed by LC-UV gives a signal to noise ratio that ranges from 14 to 40, depending on the compound. We analyzed samples collected at workplaces containing TDI, MDI and HDI with LC- MS/MS, using electrospray ionization with multiple reaction monitoring. Those results were compared with the results from HPLC-UV. The MS/MS analysis gives better selectivity with regard to interfering substances. The method was further developed to include a wide range of mono and diisocyanates with possibility to screen for oligomers.
Some Limitations in the Use of Urine Biomonitoring for Measuring TDI Exposure
Authors: Chappelle AH , Shiotsuka RN , Bartels MJ
Published: April 2008

Although reliable methods are available to monitor the concentrations of TDI in workplace air, some investigators use urine testing methods to determine if a worker has been recently exposed to TDI. This method relies on sophisticated analytical techniques in which various metabolic or breakdown products of TDI present in urine are converted in the laboratory to a derivative, toluene diamine (TDA). The total amount of converted TDA measured in the urine has been proposed as an estimate of exposure to TDI, assuming that an individual has not been exposed to another source of TDA.

Results of TDI biomonitoring may be difficult to interpret and the following points must be considered: 1) The pathway for TDI elimination has not been fully investigated in humans, a direct correlation between TDI air monitoring and urine TDA levels is not feasible; 2) Studies of TDI exposures in the workplace have not consistently shown a good correlation between air exposure levels and biomonitoring results; 3) Biomonitoring for TDI exposure by measuring converted TDA in urine does not identify peak exposures which may be more relevant to pulmonary sensitization; 4) Urine monitoring results for TDI exposure have not been correlated to adverse health effects and no biological monitoring limit has been established for TDI; 5) The detection of converted TDA in laboratory assays on processed urine samples does not necessarily reflect the presence of free TDA in the body, therefore it may unintentionally introduce concerns related to airborne TDI exposures.

Data generated from urine biomonitoring for exposure toTDI must be interpreted with caution and significant questions remain regarding the relevance of these studies for quantitative TDI exposure assessment.
Patch Testing for Isocyanates
Authors: Jolly AT , Bramann D , Hoffarth HP
Published: April 2008

Dermatitis may occur as a result of exposure to chemicals in the workplace. Approximately 30 percent of cases of chemical dermatitis are classified as allergic contact dermatitis (ACD). Irritant contact dermatitis (ICD) is due to the irritant effect of chemicals and is much more common. Toluene diisocyanate (TDI) is one of many chemicals, which are both weak skin sensitizers and irritants. Diphenylmethane diisocyanate (MDI) has also been reported to be a skin sensitizer, but there is a question whether the skin reaction is due to a breakdown product, diaminodiphenylmethane (MDA), on the surface of the skin or to a cross reaction due to structural similarities. Biochemical data lends support to the latter rather than the former hypothesis. Patch testing is widely used to establish a causal relationship between ACD and a specific causative agent, and to differentiate between ACD and ICD, which often is not possible on clinical or even histological grounds. However, there are only a handful of chemicals available in standardized commercial trays in concentrations recommended by expert international organizations. Isocyanates are among the substances for which no generally accepted concentration has been adopted. Various concentrations have been recommended and are being used. As a consequence, there are real limitations in the interpretation of patch testing, particularly in the absence of expertise with the test methodology.
Antibody Testing: Analysis of the Specificity of Antibody Detection in a Non-Diisocyanate-Exposed Population
Authors: Brown WE , Gamaluddin S , Kennedy AL
Published: April 2008

The detection of specific antibodies (IgE and IgG) in the sera of some workers exposed to diisocyanates is not always consistent and often is not well correlated with a disease state. This is particularly a concern for the testing of TDI-exposed worker populations where the intensity of the specific antibody response is low. The present study was performed to examine the baseline antibody response in a population with no known exposure to TDI. Sera from 30, non-exposed individuals were screened for specific IgG and IgG4 antibodies using a variety of synthetic antigens. Specific and nonspecific inhibition of antigen binding was performed to determine the specificity of the antibody response. One of the serum samples showed a response greater than two standard deviations above the mean for each of the test antigens. All sera except the latter sample showed generalized antigen recognition that could not be specifically inhibited. These results suggest that within the general population, nonspecific reactions can compromise the specificity of diisocyanate antibody testing.