bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibody-mediated thrombosis: Relation to the antiphospholipid syndrome
Authors: Vermylen J , Geet C Van , Arnout J
Published: March 2009

Various forms of antibody-mediated thrombosis are presented and the mechanisms involved in their pathogenesis are discussed. Antibody-mediated thrombosis includes heparin-induced thrombocytopenia and thrombosis, autoantibodies to von Willebrand factor mimicking an antiphospholipid syndrome, thrombosis following injection of the murine monoclonal antibody OKT3, hyperacute and acute xenograft rejection, and varicella-associated antibody against protein S. In several of these entities the pathogenesis of thrombosis is closely related to development of cellular procoagulant activity through tight occupancy of Fc receptors, or through complement activation, or through cell-cell interactions. Integrating the antiphospholipid syndrome into the more general category of antibody-mediated thrombosis may provide some hints as to how we could approach the study of those intriguing patients who have the clinical features of the antiphospholipid syndrome but lack those antibodies that currently characterize it.
Pregnancy loss and antiphospholipid antibodies
Authors: Lockshin M D
Published: March 2009

With the use of low-dose heparin, fetal survival of aPL pregnancies is 70-80%, but prematurity and intrauterine growth restriction are common. It is likely, but not proven, that dysregulated placental coagulation and resultant vasculopathy are the cause of fetal loss. Details of dysregulated coagulation remain to be described. Opportunities remain to determine the role of coagulopathy in repeated pregnancy loss, identify a critical event or window to which intervention might be directed, identify maternal (and fetal) characteristics other than aPL that determine fetal loss, describe toxicity profiles of current treatments, develop more specific, less toxic therapies, and describe long-term fetal and maternal outcomes.
Regulatory mechanisms of transmembrane phospholipid distributions and pathophysiological implications of transbilayer lipid scrambling
Authors: Bevers EM , Comfurius P , Dekkers DWC , Harmsma M , Zwaal RFA
Published: March 2009

The various phospholipid classes that comprise mammalian cell membranes are distributed over both leaflets of the bilayer in a non-random fashion. While a specific and ATP-dependent transporter is responsible for rapid inward movement of aminophospholipids, its inhibition does not lead to spontaneous redistribution of lipids. Conditions of cellular activation which are accompanied with increased levels of intracellular Ca2+ may cause a collapse of lipid asymmetry by switching on an ATP-independently operating scramblase, which accelerates bidirectional movement of all phospholipid classes. The most prominent change in transmembrane lipid distribution is surface exposure of phosphatidylserine (PS), the more so since conditions which activate scramblase in most if not all cases lead to inhibition of aminophospholipid translocase activity, which will prevent PS from being pumped back to the inner leaflet of the membrane. Surface-exposed PS serves at least two important physiological functions: it promotes blood coagulation and offers a recognition signal for clearance by macrophages and other cells of the reticuloendothelial system. As such, PS exposure may form an important early event in the process of apoptosis to ensure rapid removal of these cells in order to avoid release of their inflammatory contents. Defective regulation of transbilayer lipid distribution may result in clinical manifestations such as in the Scott syndrome, a bleeding disorder caused by an impaired scramblase activity. Conversely, excessive PS exposure may lead to thrombosis or may explain formation of so-called antiphospholipid antibodies as occurring in patients with antiphospholipid syndrome.
Antiphospholipid antibodies and myocardial infarction
Authors: Vaarala O
Published: March 2009

In prospective studies, increased levels of cardiolipin-biding antibodies and autoantibodies to oxidized low-density lipoprotein (LDL) have been observed in patients with myocardial infarction (MI). These findings suggest that antiphospholipid antibodies may contribute to the development of MI. The ‘oxidative-modification hypothesis’ in the pathogenesis of atherosclerotic heart disease is based on the oxidation of LDL, its accumulation into arterial wall, and the development of chronic inflammation in the atheroma. Evidence of enhanced lipid peroxidation and its association with antiphospholipid antibodies has been recently reported in SLE patients. There is also epidemiological data showing a remarkably increased risk of MI in SLE. In this review, the role of different types of antiphospholipid antibodies in the development of atherosclerotic heart disease is evaluated with particular attention to their potential pathogenic mechanisms and the possibilities in the prevention of MI associated with antiphospholipid antibodies.
Options for Assessing PPO Quality: Accreditation and Profiling as Accountability Strategies
Authors: Scanlon Dennis P. , Chernew Michael , Doty Hilary E. , Smith Dean G.
Published: March 2009

This article examines and discusses various alternatives for measuring the quality of care and services provided by preferred provider organizations (PPOs). The topic is approached from both a conceptual and a practical perspective, outlining key assumptions that underlie the desire to measure the quality of PPOs, while considering the current limitations and difficulties associated with existing PPO arrangements. Although the article does not provide normative judgments about which approach is best, it attempts to highlight the advantages and disadvantages of possible approaches in an unbiased manner. Significant attention is given to accreditation and profiling as possible methods for assessing the quality of care in PPOs.
Assessing PPO Performance on Prevention and Population Health
Authors: Schauffler Helen Halpin , McMenamin Sara
Published: March 2009

This article compares preferred provider organization (PPO) and health maintenance organization (HMO) performance on the utilization of and consumer satisfaction with preventive care. Surveys were conducted of California health plans, employers, and the insured population collected between 1996 and 1999. The authors found that PPOs were less likely than HMOs to cover some types of preventive care. PPO enrollees were less likely than HMO enrollees to receive blood pressure and mammography screenings or preventive counseling on gun safety, smoking, and sexually transmitted disease or HIV prevention. PPO enrollees were less satisfied with preventive care than HMOsenrollees. The authors concluded that there are significant differences between the rates at which preventive care is delivered in PPOs and HMOs, which can be understood in the context of PPO benefit plan design, and differences in their structural and financial characteristics. This suggests specific strategies through which it might be possible to improve preventive health care and promote population health among employees enrolled in PPOs.
Transient liquid phase bonding of 6061-15 wt-%SiCp in argon environment using Cu powder interlayer
Authors: Maity J. , Pal T. K. , Maiti R.
Published: March 2009

The transient liquid phase bonding of 6061-15 wt-%SiCp composite using 50 μm thick copper powder interlayer at 560°C temperature, 0·2 MPa pressure, with five different holding times (20 min, 1, 2, 3 and 6 h) in argon environment has been investigated. The rejection of oxide at periphery on completion of isothermal solidification and elimination of void at bond interface through solid state diffusion were the main reasons of achieving adequate joint efficiency (89%) with 6 h holding.
Comparison of inpatient vs. outpatient anterior cervical discectomy and fusion: a retrospective case series
Authors: Liu Jeffrey T , Briner Rudy P , Friedman Jonathan A
Published: March 2009

Background

Spinal surgery is increasingly being done in the outpatient setting. We reviewed our experience with inpatient and outpatient single-level anterior cervical discectomy and fusion with plating (ACDF+P).

Methods

All patients undergoing single-level anterior cervical discectomy and fusion with plating between August 2005 and May 2007 by two surgeons (RPB or JAF) were retrospectively reviewed. All patients underwent anterior cervical microdiscectomy, arthrodesis using structural allograft, and titanium plating. A planned change from doing ACDF+P on an inpatient basis to doing ACDF+P on an outpatient basis was instituted at the midpoint of the study. There were no other changes in technique, patient selection, instrumentation, facility, or other factors. All procedures were done in full-service hospitals accommodating outpatient and inpatient care.

Results

64 patients underwent ACDF+P as inpatients, while 45 underwent ACDF+P as outpatients. When outpatient surgery was planned, 17 patients were treated as inpatients due to medical comorbidities (14), older age (1), and patient preference (2). At a mean follow-up of 62.4 days, 90 patients had an excellent outcome, 19 patients had a good outcome, and no patients had a fair or poor outcome. There was no significant difference in outcome between inpatients and outpatients. There were 4 complications, all occurring in inpatients: a hematoma one week post-operatively requiring drainage, a cerebrospinal fluid leak treated with lumbar drainage, syncope of unknown etiology, and moderate dysphagia.

Conclusion

In this series, outpatient ACDF+P was safe and was not associated with a significant difference in outcome compared with inpatient ACDF+P.
Thin film flow over flexible membranes containing surface texturing: Bio-inspired solutions
Authors: Lee Y C , Thompson H M , Gaskell P H
Published: March 2009

Gravity-driven continuous thin liquid film flow over a flexible membrane containing surface topography is modelled using lubrication theory. The associated coupled non-linear equation set, for the film thickness, pressure and membrane deflection, is solved using a state-of-the-art full approximation storage multi-grid algorithm with automatic mesh refinement and adaptive time-stepping, in order to maximize computational efficiency when fine-scale resolution is required while ensuring accurate mesh-independent solutions at the micro-scale. The robustness of the approach is demonstrated through the solution of a series of problems and comparisons drawn with the same flow on an equivalent completely rigid membrane. It is shown that the former differs considerably from the latter in that the film thickness affects the shape of the flexible membrane, the compliance of which in turn impinges on the profile of the resulting free-surface disturbance.
Staphylococcal cysteine protease staphopain B (SspB) induces rapid engulfment of human neutrophils and monocytes by macrophages
Authors: Smagur Jan , Guzik Krzysztof , Bzowska Malgorzata , Kuzak Mateusz , Zarebski Miroslaw , Kantyka Tomasz , Walski Michal , Gajkowska Barbara , Potempa Jan
Published: March 2009

Circulating neutrophils and monocytes constitute the first line of antibacterial defence, which is responsible for the phagocytosis and killing of microorganisms. Previously, we have described that the staphylococcal cysteine proteinase staphopain B (SspB) cleaves CD11b on peripheral blood phagocytes, inducing the rapid development of features of atypical cell death in protease-treated cells. Here, we report that exposure of phagocytes to SspB critically impairs their antibacterial functions. Specifically, SspB blocks phagocytosis ofStaphylococcus aureusby both neutrophils and monocytes, represses their chemotactic activity and induces extensive, nonphlogistic clearance of SspB-treated cells by macrophages. The proteinase also cleaves CD31, a major repulsion (‘do not-eat-me’) signal, on the surface of neutrophils. We suggest that both proteolytic degradation of repulsion signals and induction of ‘eat-me’ signals on the surface of leukocytes are responsible for the observed intensive phagocytosis of SspB-treated neutrophils by human monocyte-derived macrophages. Collectively, this may lead to the depletion of functional neutrophils at the site of infection, thus facilitating staphylococcal colonisation and spreading.
Composite Materials: Fatigue and Fracture: Fifth Volume
Authors: Martin RH
Published: March 2009

Description

Features the latest information on methods for predicting how composite materials and composite material structures fail. 27 peer-reviewed papers from the world's leading professionals in the field. Five key areas:

Delamination Characterization -- Eight papers explore the challenges of characterizing delamination fracture of laminated composite materials in terms of interlaminar fracture toughness.

Damage Modeling -- Developing appropriate models for predicting composite damage such as matrix cracking, fiber failure and delamination are considered in five papers.

Material Damage Characterization -- Five papers investigate how environmental exposure and mechanical loads damage composite materials.

Impact -- Methods to predict the effect of impact on laminated composite materials are explained in four papers.

Structural Damage Characterization -- Five papers describe failure or damage issues in specific structures.
Atmospheric Corrosion
Authors: Kirk WW , Lawson HH
Published: March 2009

Description

This comprehensive publication presents 16 international papers on atmospheric corrosion and corrosion testing. Provides an understanding of atmospheric corrosion concerns from the standpoint of economics, safety, and aesthetics, and what is being done about them on four continents.

Topics include:

• Corrosion on basic metals and alloys used in construction, including: carbon steel, stainless steel, weathering steel, zinc, copper, and aluminum

• Results of an ISO program to characterize different atmospheres as to corrosivity

• Acid deposition and its effects on corrosion Marine corrosion.
The Use of Chemicals in Oil Spill Response
Authors: Lane P
Published: March 2009

Description

The latest research and design developments in the area of oilspill control dispersants and other chemicals. This comprehensive volume provides up-to-date information on how best to deal with this environmental concern, with a special focus on three categories:

Laboratory Work: Testing oil spill dispersants, water-in-oil emulsion breakers, and performance evaluation methods for oil spill chemical dispersants.

Ecological Considerations: Marine life response to dispersed oil; resolving related ecological issues; and how dispersants perform under arctic conditions.

Operational Considerations: Dispersant application by Fire Monitor; a shoreline cleaner evaluation; oil droplet size measurements at sea; oil spill testing agents; and how breaking wave conditions impact chemical dispersants.
Nonmetric Clustering and Association Analysis: Implications for the Evaluation of Multispecies Toxicity Tests and Field Monitoring
Authors: Matthews GB , Matthews RA , Landis WG
Published: March 2009

Many techniques developed by computer scientists in the field of artificial intelligence (AI) are currently being used as standard, state-of-the-art technology. These techniques have proven their value and validity in medicine, geology, agronomy, and astronomy time and again, often beating human experts at their own game. We present here an analysis tool for multispecies data based on nonmetric clustering, an AI technique developed specifically to aid in the interpretation of complex ecological data sets. This technique uses AI search to find an appropriate and meaningful characterization of a multivariate system. After appropriately characterizing the system in this fashion, the relationship between this characterization of the system and the critical environmental variables (pollution, toxicity, etc.) can be quantitatively analyzed to aid in the assessment of the effects of the environment on the system. A priori endpoints or indices are not necessary; the data are allowed to determine the variables that best separate treatment from controls.

We have now tested this methodology over a series of multispecies toxicity tests using a variety of Stressors. During the initial blind testing the methodologies could pick treatment groups with high accuracy. When knowledge of treatment group is available, oscillations in the similarity of the treatments to the controls are apparent.

Much recent debate in toxicological studies has focussed on appropriate endpoints for multispecies toxicity tests and biomonitoring schemes. We suggest that the search for endpoints appropriate to the entire field of toxicity testing is a fruitless search. We recommend instead an approach that standardizes the common sense approach: different situations, even within a single experiment, call for different endpoints. Typically, the toxicologist, if called upon for an expert opinion, will examine multivariate data, and extract from that data a few critical species. The behavior of these species will give an adequate (though perhaps not complete) picture of the toxic effects. Which species are selected, and whether it is their mortality, behavior, or biomass that is important, will always vary from case to case. We call, therefore, for more research into the automation of the process typically performed by the expert. The selection of species, as well as other parameters, as significant for a particular experiment or field study, can be done automatically by computer algorithms. To be blind to the utility of these tools in the field of toxicology is to work by hand, over and over again, problems which could be solved in a twinkling with their aid.
Dredging, Remediation, and Containment of Contaminated Sediments
Authors: Demars KR , Richardson GN , Yong RN , Chaney RC
Published: March 2009

Description

The first publication of its kind to focus on the problems of contaminated dredged material disposal.

22 peer-reviewed papers are presented in the following wide-ranging categories:

• Sediment Characterization

• Dredging Transport and Handling

• Restoration/Remediation

• Containment and Isolation

• and Management Strategies.
Denatonium Benzoate Use to Mitigate Pesticide Ingestion
Authors: Payne HAS , Tracy MJ
Published: March 2009

Denatonium Benzoate (DB), an extremely bitter lignocaine derivative, has been used world wide as an alcohol denaturant for over 30 years. Recent recognition of its application for deterring ingestion of potentially toxic products has led to its introduction as an inert ingredient in pesticides, automotive chemicals and household goods. To determine the applicability of DB use in particular formulations, a standard research protocol has been developed. This assures compatibility, stability and optimum DB concentration to effect a bitter taste in the formulated product. This paper discusses compatibility issues, presents data on product stability and the use of human subjects for taste trials.
Phytotoxic Evaluation of Commercial Pesticide Products Formulated with Low and High Flash Point Hydrocarbon Fluids
Authors: Sandler RL , Chambers GV , Verbelen RA , Herold A
Published: March 2009

Low flash point (⩽ 60°C) aromatic hydrocarbon fluids are still widely used in the Agricultural Chemical Industry. The pending HM181 DOT regulation will greatly increase the costs (i.e. handling, shipping, storage, insurance, relabeling) associated with using a 60°C and lower flash point hydrocarbon fluid. Formulators can avoid these cost increases by replacing the low flash hydrocarbon fluids with higher flash material, provided additional phytotoxicity concerns are not posed. A field trial study was designed to measure the change in crop response (phytotoxicity) with respect to a change in flash point.
Effects of Nonionic Surfactants on Properties of Water Dispersible Granule Formulations
Authors: Utz CG , Sekmistrz JM , Hollis RP
Published: March 2009

Nonionic surfactants are not generally used in water dispersible granule formulations. Common dispersants for these systems include lignin sulfonates and naphthalene sulfonates. Recent studies have shown that ethylene oxide/propylene oxide (EO/PO) block copolymers can also be used to stabilize atrazine dry flowables in both pan granulation and extrusion processes. In laboratory tests, they impart better granule hardness and provide markedly improved suspensibility compared to the anionic dispersants. Most of the formulations tested show good particle size stability over time at room and elevated temperatures. Some particle size increase was seen in some formulations at 45°C.

Blends of these dispersants can be used to provide desired performance characteristics. Combining different ratios of nonionic and anionic dispersants impart varying properties to the granules. Increasing the amount of anionic surfactant can lower the particle size and reduce settling while maintaining the hardness and suspensibility obtained from the nonionic component. The performance of the anionic/nonionic blend in the granules is favorable when compared to the classical anionic formulation.

The molecular weight of the EO/PO block can also influence particle size (measured via wet screen analysis). As the total molecular weight is raised and the EO chain length thus increased, particle size decreases and suspensibility is improved. This result indicates a better dispersive capacity for the larger molecules.

In extruded granules, EO/PO blocks offer not only improved suspensibility and hardness but also equivalent particle size to an anionic dispersant. Obvious differences exist between surfactant performance in extrusion as opposed to that in pan granulation.
Nonionic Surfactant Properties Affect Enhancement of Herbicides
Authors: Manthey FA , Czajka M , Nalewaja JD
Published: March 2009

Research was conducted to determine the effect of nonionic surfactant properties on herbicide phytotoxicity to green foxtail. Herbicides evaluated were commercially formulated imazethapyr, nicosulfuron, quinclorac, rimsulfuron, and sethoxydim. Hydrophilic: lipophilic balance (HLB) was the only surfactant property that affected phytotoxicity enhancement of imazethapyr, quinclorac, rimsulfuron, or sethoxydim. Surfactant enhancement of nicosulfuron was affected by surfactant HLB, cloud point temperature, and pour point temperature. Optimum octoxynol HLB value for sethoxydim enhancement was 13.4 and for imazethapyr, nicosulfuron, quinclorac, and rimsulfuron between 15 and 16. Surfactants having similar HLB values but different chemistry differed in their enhancement of herbicide phytotoxicity to green foxtail. Surfactant efficacy was herbicide dependent. The results of these experiments indicate that surfactant efficacy is determined by the physical and chemical properties of the surfactant and the herbicide.
Improving Insecticide Activity and Rain-Fastness with Polyethylenimine
Authors: Feigenbaum HN
Published: March 2009

Many surfactant or polymer-based adjuvants designed to improve the adhesion of active ingredients on plants function through mechanisms involving surface tension modification or hydrogen bonding. Polyethylenimine, a branched polyamine with high molecular weight and cationic charge density, offers a different adhesion promotion mechanism based on the formation of ionic bonds with anionic substrates combined with an ability to orient itself with organic active ingredients.

The product is particularly beneficial with pesticide actives which function through a contact mechanism and demonstrates an ability to improve pesticide efficacy particularly in terms of rain-fastness, adhesion, heavy metal complexation, biodegradation, and initial fixation level.
Enzyme-Linked Immunosorbent Assay for Quantification of Bacillus Thuringiensis Var. Kurstaki Crystalline Protein in Some Commercial Formulations
Authors: Sundaram KMS , Sundaram A , Gee SJ , Harrison RO , Hammock BD
Published: March 2009

The widespread use of microbial pesticides for forest insect control necessitates determination of the delta-endotoxin protein levels in commercial formulations to optimize their use-patterns in the field. As the analyte is biochemical and/or biological in nature, classical analytical procedures are often not applicable for this purpose, and new types of analytical methods need to be developed. A sandwich type enzyme-linked immunosorbent assay (ELISA) was developed to detect and quantify Bacillus thuringiensis var. kurstaki delta-endotoxin in nine commercial formulations that are being used for forest insect control in North America. Formulation ingredients (formulants) interfered with the toxin response in three of the nine formulations, and the total protein needed to be separated from formulants for ELISA. Total protein levels were consistently higher (about 40 to 60%), in all formulations than the delta-endotoxin content because of the presence of inactive proteins. Results of three types of force-feeding bioassays [using spruce budworm, Choristoneura fumiferana (Clemens.)] viz., with diluted formulations, formulation extracts, and redissolved protein precipitates, showed that the formulants contributed to bioactivity and had to be removed to assess toxicity of the BTK protein alone. The delta-endotoxin content of formulations correlated better with the LD50's (ng of total protein/larva required for 50% mortality) of the redissolved protein precipitates of formulations than with those of the diluted formulations and formulation extracts. As more microbial pesticides are being introduced for forest insect control, it is crucial that analytical methods are in place for quality control of commercial formulations, both from the standpoint of improved efficacy and environmental safety.
The influence of pH on the Performance of Organosilicone Surfactants
Authors: Policello GA , Stevens PJG , Forster WA , Murphy GJ
Published: March 2009

Trisiloxane based spreading agents are a unique class of surfactants that enhance spray coverage and, in many cases, increase the uptake of agrochemicals into plant tissue through stomatal flooding. The degree of uptake is closely related to the spreading ability of these surfactants. Solution pH is a key influence on the performance of trisiloxanes. These materials undergo rapid hydrolysis at extremes in pH, and therefore show a marked decrease in spreading and uptake of chemicals into leaf tissue. Buffering solutions of the trisiloxane surfactants to a neutral pH increases their hydrolytic stability from hours to > 2 years.
Feasibility Studies of Bioremediation of Hydrocarbon-Contaminated Soils
Authors: Elektorowicz M , Yong RN
Published: March 2009

In-situ and ex-situ bioremediation of contaminated soil should be a priori tested during feasibility studies. Three cases of feasibility studies are presented in this paper. Each one concerns a different type of soil contaminated by various hydrocarbons. Different techniques of bioremediation have been chosen in every case. The natural clayey soil and clayey fill soil were provided for the ex-situ treatment but in-situ treatment was applied to sandy soil. The clayey soil was pretreated before subjection to bioremediation. The final results of feasibility studies for all cases show a limited possibility of bio-treatment. The bioremediation needs supplementary optimisation of technological parameters before its application on site.
In Situ Bioremediation Pilot Study at a Former Manufactured Gas Plant Site
Authors: English DA , Nelson JR , Hargens DA
Published: March 2009

A one-year in situ bioremediation pilot study was implemented in January 1992 at a site contaminated with polynuclear aromatic hydrocarbons, benzene, ethyl benzene, toluene, and xylenes from former manufactured gas plant operations. The objective of the study was to evaluate the effectiveness of in situ bioremediation on high molecular weight hydrocarbons under site conditions.

The pilot study involved injecting treated groundwater amended with nutrients and oxygen (in the form of hydrogen peroxide) into the subsurface via an injection well, extracting groundwater through a downgradient extraction well, and periodically monitoring the system using monitoring wells and soil borings.

Results indicate that the site hydrogeology, the high concentrations of target and non-target organics, and the presence of pure-phase coal tar in the subsurface limit the cost-effective application of in situ bioremediation at this site.
An In-Situ Slurry-Phase Bioremediation Case with Emphasis on Selection and Design of a Pure Oxygen Dissolution System
Authors: Bergman TJ , Greene JM , Davis TR
Published: March 2009

A field-scale, in-situ, slurry-phase bioremediation demonstration was conducted at the French Ltd. Superfund Site in Crosby, Texas. As part of this study, several aeration technologies were compared, based on reliability, organic chemical emissions levels, mixing, and oxygenation characteristics. An economic and technical comparison was drawn between these technologies and several high-purity oxygen-based technologies, including Praxair's (formerly, Union Carbide Industrial Gases) Mixflo™ system. Based on cost and air emissions, the Mixflo™ system was selected, and a field-scale system was designed for the French Ltd. Site. This system is currently operating.
Rhizosphere Microbial Communities of Herbicide-Tolerant Plants As Potential Bioremedients of Soils Contaminated with Agrochemicals
Authors: Anderson TA , Kruger EL , Coats JR
Published: March 2009

Plant roots influence the soil in which they grow in a variety of ways, making the soil more conducive for microbial growth and activity, as well as cometabolic reactions. Studies examining the fate of pesticides in plant-soil systems have revealed a marked decrease in persistence of these compounds. Additionally, similar observations have recently been made for oil residues, polycyclic aromatic hydrocarbons, trichloroethylene, and surfactants. These previous studies suggest that the root zone could potentially be managed to effect bioremediation of surface soils containing hazardous organic compounds through enhanced biochemical transformation of these organic constituents at waste sites by indigenous rhizosphere microorganisms. In order to further test this hypothesis, a study was initiated using soil and vegetation from an existing pesticide-contaminated site in Iowa. Initial characterization of this site revealed several herbicide-tolerant plant species including Kochia sp., knotweed (Polygonum sp.), and crabgrass (Digitaria sp.). Experiments testing the influence of these tolerant varieties on microbial degradation of a mixture of herbicides are reported. By facilitating microbial degradation of pesticide wastes, vegetation could provide a cost-effective and ecological approach to restoration of contaminated surface soils in situ.
Mechanisms of Heavy Metal Uptake in a Mixed Microbial Ecosystem
Authors: Ibeanusi VM , Archibold EA
Published: March 2009

The potential use of a mixed microbial ecosystem for the bioremediation, and removal of heavy metals from contaminated water and soil was investigated. The study included the development of metal-tolerant microbial strains for increased metal recovery, and the investigation of the uptake dynamics of (CrVI), Pb, and Se. The results indicated that the microbial growth dynamics towards a stable mat structure resulted in a typical two microbial phase pattern: (1) a mixed bacterial bloom, during which the metal ions were enzymatically detoxified, and mobilized towards the pond surface, and (2) a cyanobacterial phase, a period marked by the stabilization of the metal species in the floating microbial mat. Investigation of the bioremediation processes suggested that reduction by microbial sulfate reactions, precipitation of metal ions, adsorption at bacterial membrane sites, reduction by change of oxidation states, and chelation played major roles in describing the strategies of bacterial response to the heavy metals investigated.
Bioremediation Application in the Cleanup of the 1989 Alaska Oil Spill
Authors: Lessard RR , Wilkinson JB , Prince RC , Bragg JR , Clark JR , Atlas RM
Published: March 2009

Following the Valdez spill in Alaska in 1989, Exxon scientists worked closely with the U. S. Environmental Protection Agency (EPA) and the State of Alaska, to conduct the most extensive bioremediation study on oiled shoreline ever carried out. Over $10 million was spent conducting this research. The process involved applying fertilizers on intertidal shorelines to stimulate the growth of indigenous oil-degrading microbes and accelerate the rate of natural degradation of the oil. In analyzing the data from this program, Exxon developed unique approaches, focusing on specific changes in the oil chemistry to verify the degradation rate increase provided by the added nutrient. Such a sophisticated approach was required because of the problems inherent with measurement of total petroleum hydrocarbon in the sediment to define the degradation rate. Results show that the rate of oil biodegradation on fertilized beaches was from three to more than five times faster than on unfertilized beaches.

This paper summarizes the bioremediation research conducted, and the extensive information obtained. The experience gained by Exxon, including pioneering work on internal markers, applies directly to bioremediation studies in other environments. Some of this experience is being extended to the remediation of inland contaminated sites and there is a major effort now underway to identify low-cost bioremediation techniques for in-situ restoration of such sites.
Establishment of Fatigue Test Method for Turbine Blade Fastener
Authors: Endo T , Kondo Y , Kadoya Y
Published: March 2009

The design of a long, wide blade for a large-sized steam turbine required the development of new design methodology. The most important consideration to ensure the integrity of a blade attachment is to evaluate the stress at the local point of a blade root. The major difficulties in stress evaluation are the three-dimensional effects and the contact problem at the fastening point between the blade root and the disk steeple. Because of these complexities, the design method based on the linear elastic finite-element method (FEM) analysis has to be verified experimentally.

For this purpose, a new fatigue testing apparatus was developed that simulates the operating loads for the steam turbine, including centrifugal forces, untwisting moments, and bending moments. The results of the strain measurement and the low-cycle fatigue tests verified the use of the peak stress, which was calculated by three-dimensional elastic FEM analysis using linear elastic connection of blade root and disk steeple and Neuber's rule for the evaluation of the strain range. If the strain is evaluated correctly, the low-cycle fatigue life can be obtained using a Langer's-type equation.
Failure Criteria and Limiting States of Stress for Cracked Bolts/Studs
Authors: Kagan V
Published: March 2009

Service time and the strength of high-stressed threaded connections under cyclic nonlinear stress-strain conditions are determined by the behavior of the fatigue crack's initiation and propagation stages in local stress-strain concentration areas of threaded components. The ultimate states and failure criterion of cracked bolts/studs have been determined by analysis of the parameters of linear and nonlinear deformation and fracture mechanics. Evaluation of the number of cycles of fatigue crack initiation Nc and the number of cycles to final failure Nf for different design joints required an all-round consideration of cyclic nonelastic (nonlinear) stress-strain behavior. It also needed the further study of the influence of the conditions of cyclic, mechanical, and thermal loadings, as well as assembly and manufacturing based on the theoretical stress concentration factor Kt, (elastic deformation), stress Kσ, and strain Kϵ (nonelastic deformation) factors' values in the mated-loaded (engaged) and nonloaded (free) thread turns. The analysis indicated a linear relation between critical value hmax of the fatigue crack's depth and the cycle amplitude's stress σa, as well as a correlation with the limiting value of the stress (strain) intensity factor. The remaining strength and fatigue life of the cracked threaded components are evaluated taking into consideration the values of the current thresholds and the limiting stress and strain intensity factor. The conditions of their applicability depend on the applicability of linear (elastic) or nonlinear (elastic-plastic) fracture mechanics criteria.
Stress Intensity Factors for Surface and Corner-Cracked Fastener Holes by the Weight Function Method
Authors: Zhao W , Atluri SN
Published: March 2009

The paper presents stress intensity factor solutions for surface and corner-cracked fastener holes by using an efficient and accurate three-dimensional weight function method. The approach is briefly described. Stress intensity factors for crack-face pressure loads of the type (x/r)n are provided, where n varies from 0 to 4. The geometry parameters considered are as follows: the ratio of the hole radius to plate thickness r/T = 1.5 (T = t for corner cracks, T = 2t for surface cracks); the crack aspect ratio a/c = 0.5, 1, and 1.5; the ratio of crack depth-to-plate thickness a/t = 0.1, 0.3, and 0.5. Based on the given solutions and the superposition principle, stress intensity factors for other load cases may be easily obtained. Examples are given for remote tension, biaxial tension, wedge loading in the hole, and simulated pin loading. Also, the effect of the residual stress field following cold expansion is considered for the remote tension loading condition.
The Representation of Concept Systems
Authors: Riggs FW
Published: March 2009

The Compilation of ASTM Standard Definitions [1] is an admirable work that helps members identify the concepts they need and find approved terms to designate them. Unfortunately, it has two major limitations, but they can be corrected quite easily, especially if the information is put into machine readable form via a low (or no) cost hypertext system. The first limitation involves a lack of the symbols needed to indicate how these concepts are related to each other in a system. Such symbols could easily be developed and displayed through an index. The second limitation arises from the potential for ambiguity created by the use of some keywords to designate more than one concept. This problem can easily be overcome by adding supplementary terms that represent only one concept in this system. An important obstacle to doing this arises from the confusing use of some technical terms borrowed from lexicography, notably polysemy and homonymy. If they could be replaced by more appropriate terms, rooted in the requirements of terminology work, this second difficulty could more easily be overcome.
Implementing the Terminology Interchange Format
Authors: Melby AK
Published: March 2009

This paper suggests how one might use the Electronic Terminology Interchange Format (ETIF) to import and export terminology files. ETIF is currently under development in ISO Technical Committee 37, Terminology: principles and coordination, Sub-committee 3 for Computational Aids in Terminology. It is available as ISO DIS 12200, Computational Aids in Terminology — Terminology Interchange Format (TIF) — An SGML Application. The paper proposes a set of scenarios in which an individual or organization would desire to interchange terminology with other sources using different software and/or hardware platforms to record, store and manipulate terminological data. The discussion outlines the specific problems involved in converting such data from one environment to another and details the specific steps that a user would have to follow to implement such an interchange. The paper concludes by listing important addresses and resources that would be useful for anyone approaching this problem for the first time.
Mixed Mode Interlaminar Fracture Toughness of Unidirectional Glass/Epoxy Composite
Authors: Gong X-J , Benzeggagh M
Published: March 2009

The objective of this work is to evaluate the interlaminar fracture toughness, in terms of the total critical strain energy release rate (GTc), for unidirectional glass/epoxy composites under mixed Mode I + II loading. Several bending tests proposed in the literature, such as the DCB, MMF, ENF, and CLS tests, were performed. In addition, the mixed mode CBON and IDCB tests were developed. The combination of these tests gave fracture toughness results that covered a complete mixed mode range: 0 ≤ GII/GTc ≤ 1. The GTc and the individual components, GI and GII, were determined analytically by the beam theory and by finite element calculation. Measurements of these parameters using experimental compliance calibration were compared with the analytical results to ensure their validity. Both the testing and analytical methodologies are discussed. The influence of specimen configuration on the GTc values was also investigated. Fractography provided a way to understand the fracture mechanisms and to associate the fracture surface morphology with the variation of the GTc.

Based on experimental data obtained, a new mixed mode delamination criterion has been proposed.
Prediction of Energy Release Rate for Edge Delamination Using a Crack Tip Element Approach
Authors: Davidson BD
Published: March 2009

Edge delamination in composite laminates is analyzed using a closed form, crack tip element approach. Classical laminated plate theory is utilized for the crack tip element formulation. Energy release rates and fracture mode ratios as found by this new approach are shown to agree with finite element results for mechanical, hygrothermal, and combined loadings. For those cases where a linear elastic solution predicts a near-field oscillatory singularity, a relatively simple method is proposed that allows a unique value of fracture mode ratio to be defined.
Non-Penetrating Impact Behavior of CFRP at Low and Intermediate Velocities
Authors: Delfosse D , Poursartip A , Coxon BR , Dost EF
Published: March 2009

A series of instrumented impact tests have been carried out using two different CFRP laminates, IM6/937 with a relatively brittle matrix and T800H/3900-2 with a toughened matrix. Two impactor masses differing from each other by a factor of 20 were used to study the effect of impact velocity and rate of loading.

Differences in the target impact response were found when the panels were impacted with the same energy but at different velocities. The higher velocities led consistently to slightly higher measured peak forces, but lower maximum deflections. This difference is reflected in the resultant damage state. The measured delamination area is larger for the high-mass impacts at the same incident impact energy, particularly for the tough matrix system. However, when the delamination size is correlated with the impactor energy loss, the mass effect disappears. The low-mass, high-velocity impacts create large contact forces, which leads to significant fiber breakage on the impact face. Fiber breakage throughout the rest of a panel is lower, which can be explained by the lower maximum panel deflections observed in low-mass impacts. An energy balance that takes into account the work done in delamination and fiber breakage gives good agreement with the measured impactor energy loss over the complete range of impact energies tested.
Post-Impact Fatigue Response of Stitched Composites
Authors: Moon DG , Kennedy JM
Published: March 2009

The post-impact fatigue response of stitch-reinforced carbon/epoxy composite materials was evaluated. Five different material configurations, all based on a 48-ply quasi-isotropic laminate, were used in this study. Three different stitch densities and two separate resin systems were used in combination with AS4 fiber uniwoven lamina for these composites. An unstitched baseline laminate was also evaluated. After the samples were impacted using a drop tower, tension-compression fatigue tests were conducted with a 4-Hz frequency and a stress ratio of R = -5. Damage progression was monitored by radiographic techniques and extensometers mounted over the impact site. All the stitched materials developed a narrow self-similar damage zone transverse to the loading direction, which emanated from the damage site. Only very minor damage developed in the longitudinal loading direction of any of the stitched samples. While the lightly stitched tougher resin material had the best fatigue performance, a highly stitched brittle system behaved comparably. The current generation of stitched material was found to provide twice the fatigue load-carrying capability of the baseline unstitched laminate. Reinforcement was also determined to improve the impact damage tolerance of the materials while incurring no undamaged static compressive strength penalty.
Damage Tolerance and Arrest Characteristics of Pressurized Graphite/Epoxy Tape Cylinders
Authors: Ranniger CU , Lagace PA , Graves MJ
Published: March 2009

An investigation of the damage tolerance and damage arrest characteristics of internally pressurized graphite/epoxy tape cylinders with axial notches was conducted. An existing failure prediction methodology, developed and verified for quasi-isotropic graphite/epoxy fabric cylinders, was investigated for applicability to general tape layups. In addition, the effect of external circumferential stiffening bands on the direction of fracture path propagation and possible damage arrest was examined. Quasi-isotropic [90/0/±45]s and structurally anisotropic [±45/0]s and [±45/90]s coupons and cylinders were constructed from AS4/3501-6 graphite/epoxy tape. Notched and unnotched coupons were tested in tension and the data correlated using the equation of Mar and Lin. Cylinders with through-thickness axial slits were pressurized to failure achieving a far-field two-to-one biaxial stress state. Experimental failure pressures of the [90/0/±45]s cylinders agreed with predicted values for all cases but the specimen with the smallest slit. However, the failure pressures of the structurally anisotropic cylinders, [±45/0]s and [±45/90]s, were above the values predicted utilizing the predictive methodology in all cases. Possible factors neglected by the predictive methodology include structural coupling in the laminates and axial loading of the cylindrical specimens. Furthermore, applicability of the predictive methodology depends on the similarity of initial fracture modes in the coupon specimens and the cylinder specimens of the same laminate type. The existence of splitting, which may be exacerbated by the axial loading in the cylinders, shows that this condition is not always met. The circumferential stiffeners were generally able to redirect fracture propagation from longitudinal to circumferential. A quantitative assessment for stiffener effectiveness in containing the fracture, based on cylinder radius, slit size, and bending stiffnesses of the laminates, is proposed. Suggestions for further work in these areas to better understand the mechanisms at work, and thus provide a better predictive methodology, are offered.
Influence of Realistic Ply-Drop Geometries on Interlaminar Stresses in Tapered Laminates
Authors: Vizzini AJ
Published: March 2009

A finite element model of a tapered specimen was developed that incorporates naturally occurring realistic geometries such as ill-formed resin pockets, unsymmetric and offset ply-drop locations, varying ply thickness, and voids. Parametric studies were performed to determine the effects of these geometries, which occur naturally in a manufactured specimen. Illformed resin pockets increase the effective taper angle at the ply drop and cause a corresponding increase in the interlaminar stresses. In addition, the onset of damage location is dependent on the geometry of the ill-formed pocket. The effect of ply drops occurring unsymmetrically about the midplane is significant for offset values that occur as a result of the manufacturing process. Again the location for damage onset is dependent on the amount of the offset of the resin pocket. Voids or fracture within the resin pockets significantly increase the interlaminar stress at the ply drop and thus decrease the damage onset load within the tapered element.