Acute Toxicity of Binary Mixtures of Five Cations (Cu2+, Cd2+, Zn2+, Mg2+, and K+) to the Freshwater Amphipod Gammarus lacustris (Sars): Alternative Descriptive Models

1988 ◽  
Vol 45 (4) ◽  
pp. 625-633 ◽  
Author(s):  
B. G. E. de March
Keyword(s):  
Acute Toxicity ◽  
Mixture Toxicity ◽  
Probit Model ◽  
Response Surfaces ◽  
Additive Effects ◽  
Similar Action ◽  
Surface Models ◽  
Complex Linear ◽  
Different Response ◽  
Toxicity Indices

The combined results of 10 acute toxicity experiments, each testing the joint toxicity of two of the ions Cu2+, Cd2+, Zn2+, Mg2+, and K+, were examined in terms of different response surface models which could be used to make decisions about limiting toxic components in mixtures. The classical probit model for simple similar action described experimental results satisfactorily with a model R2 of 0.282; equations in which probit(p) was described directly by a linear combination of toxicant concentrations fit data significantly better, with an R2 of 0.527. Equations with more complex linear terms and appropriate weighting factors applied to the residual sums of squares yielded R2 values up to 0.931. Predicted LC50 values were midrange compared with published values. Based on the linear description of the probit response, K or Mg in combination with either of Cu, Cd, or Zn had additive effects, the combinations Cu and Cd, Cu and Zn, and Cd and Zn had more-than-additive effects, and Mg and K had less-than-additive effects. The relationships between the response surfaces, other described modes of joint action, the toxic units model, and mixture toxicity indices are discussed.

scholarly journals Dose-response surface fits to drought and nitrogen limitation applied together allow mapping of loci that exhibit nonlinear responses

2017 ◽  
Author(s):  
Megan M. Chang ◽  
Danielle Allery Nail ◽  
Toni Kazic ◽  
Susan J. Simmons ◽  
Ann E. Stapleton
Keyword(s):  
Response Surface ◽  
Dose Response ◽  
Genetic Architecture ◽  
Environmental Changes ◽  
Crop Improvement ◽  
Crop Protection ◽  
Three Dimensional ◽  
Response Surfaces ◽  
Protection Measures ◽  
Different Response

ABSTRACTCrop improvement must accelerate to feed an increasing human population in the face of environmental changes. Breeding programs can include anticipated climatic changes and genetic architecture to optimize improvement strategies. We analyzed the genetic architecture underlying the response of Zea mays to combinations of water and nitrogen stresses. Recombinant inbreds were subjected to nine combinations of the two stresses using an optimized response surface design, and their growth was measured. Three-dimensional dose response surfaces were fit globally and to each polymorphic allele to determine which genetic markers were associated with different response surfaces. Three quantitative trait loci that produced nonlinear surfaces were mapped. Alleles that performed better in combinations of mid-range stresses were typically not the alleles that performed best under combinations of extreme stresses. To develop physiologically relevant models for future genetic analyses, we modeled the network that explains the response surfaces. The network contains two components, an elliptical paraboloid and a plane, that each combine the nitrogen and water inputs. The relative weighting of the two components and the inputs is governed by five parameters. We estimated parameter values for the smoothed surfaces from the experimental lines using a set of points that covered the most distinctive regions of the three-dimensional surfaces. Surfaces computed using these values reproduced the smoothed experimental surfaces well, especially in the neighborhood of the peaks, as judged by three different criteria. The parameters exaggerated the amplitudes of the simulated surfaces. Experiments using single stresses could misestimate responses to their combinations and disguise loci that respond nonlinearly. The three-dimensional shape evaluation strategy used here more thoroughly compares nonlinear, nonplanar responses. We encourage the application of our findings and methods to experiments that mix crop protection measures, stresses, or both, on elite and landrace germplasm.

Evaluation of Driver Comprehension and Visual Attention of the Flashing Yellow Arrow Display for Permissive Right Turns

2019 ◽  
Vol 2673 (8) ◽  
pp. 397-407 ◽  
Author(s):  
Hisham Jashami ◽  
David S. Hurwitz ◽  
Christopher Monsere ◽  
Sirisha Kothuri
Keyword(s):  
Visual Attention ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Driving Simulator ◽  
Probit Model ◽  
Flashing Yellow Arrow ◽  
Different Response ◽  
Turning Maneuver ◽  
Yellow Arrow ◽  
Right Turns

This research explored driver comprehension and behaviors in Oregon with respect to right-turn signal displays focusing on the Flashing Yellow Arrow (FYA) in a driving simulator. A counterbalanced, factorial design was chosen to explore three independent variables: signal indication type and active display, length of the right-turn bay, and presence of pedestrians. Driver decision-making and visual attention were considered. Data were obtained from 46 participants (21 women, 25 men) turning right 736 times in 16 experimental scenarios. A Mixed-effects Ordered Probit Model and a Linear mixed model were used to examine the influence of driver demographics on observed performance. Results suggest that the FYA indication improves driver comprehension and behavioral responses to the permissive right-turn condition. When presented with the FYA indication in the presence of pedestrians, nearly all drivers exhibited caution while turning and yielding to pedestrians and stopping when necessary. For the same turning maneuver, drivers presented with a circular green (CG) indication were less likely to exhibit correct behavior. At least for Oregon drivers, another clear finding was a general lack of understanding of the steady red arrow (SRA) display for right turns. Most drivers assume the SRA indication requires a different response than the circular red (CR) and remain stopped during the entire red interval, thus resulting in efficiency losses. These findings suggest that transportation agencies could potentially improve driver yielding behavior and pedestrian safety at signalized intersections with high volumes of permissive right turns from exclusive right-turn lanes by using the FYA display in lieu of a steady CG display.

Interaction of alcohol and drugs in fatal poisonings

2003 ◽  
Vol 22 (5) ◽  
pp. 281-287 ◽  
Author(s):  
Anna Koski ◽  
Ilkka Ojanperä ◽  
Erkki Vuori
Keyword(s):  
Acute Toxicity ◽  
Blood Alcohol Concentration ◽  
Alcohol Concentration ◽  
The Other ◽  
Blood Alcohol ◽  
Single Drug ◽  
Alcohol And Drugs ◽  
Low Concentrations ◽  
Postmortem Blood ◽  
Toxicity Indices

In Finnish data from 1995 / 2000, 1006 fatal poisonings due to alcohol (ethanol), a single drug or both were statistically analysed in retrospect to evaluate the interaction between alcohol and drugs. In 53% of these cases, low concentrations of some common benzodiazepines were present. The median postmortem blood alcohol concentration (BAC) was 3.3 (w/w) in the 615 alcohol poisonings, but significantly lower, ranging from 1.3 to 1.7, when promazine, doxepin, amitriptyline or propoxyphene were found together with alcohol. When levomepromazine, temazepam or zopiclone were present, the median BAC was also significantly lower, 2.5 trations of a drug (excluding citalopram), suggesting a positive concentration / effect relationship. Fatal toxicity indices (FTIs) were calculated by relating the number of deaths caused by a drug to the corresponding sales figures. Promazine had an extremely high FTI, followed by levomepromazine, propoxyphene, doxepin and amitriptyline. The other drugs had relatively low FTIs. The results reflect not only the acute toxicity of a given drug / alcohol combination but also the manners of use and abuse of these drugs.

scholarly journals Effect of the Albumin Corona on the Toxicity of Combined Graphene Oxide and Cadmium to Daphnia magna and Integration of the Datasets into the NanoCommons Knowledge Base

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1936 ◽  
Author(s):  
Diego Stéfani T. Martinez ◽  
Gabriela H. Da Silva ◽  
Aline Maria Z. de Medeiros ◽  
Latif U. Khan ◽  
Anastasios G. Papadiamantis ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Acute Toxicity ◽  
Knowledge Base ◽  
Daphnia Magna ◽  
Colloidal Stability ◽  
Cadmium Toxicity ◽  
Toxicity Testing ◽  
Mixture Toxicity ◽  
Water Quality Monitoring ◽  
Corona Formation

In this work, we evaluated the effect of protein corona formation on graphene oxide (GO) mixture toxicity testing (i.e., co-exposure) using the Daphnia magna model and assessing acute toxicity determined as immobilisation. Cadmium (Cd2+) and bovine serum albumin (BSA) were selected as co-pollutant and protein model system, respectively. Albumin corona formation on GO dramatically increased its colloidal stability (ca. 60%) and Cd2+ adsorption capacity (ca. 4.5 times) in reconstituted water (Daphnia medium). The acute toxicity values (48 h-EC50) observed were 0.18 mg L−1 for Cd2+-only and 0.29 and 0.61 mg L−1 following co-exposure of Cd2+ with GO and BSA@GO materials, respectively, at a fixed non-toxic concentration of 1.0 mg L−1. After coronation of GO with BSA, a reduction in cadmium toxicity of 110 % and 238% was achieved when compared to bare GO and Cd2+-only, respectively. Integration of datasets associated with graphene-based materials, heavy metals and mixture toxicity is essential to enable re-use of the data and facilitate nanoinformatics approaches for design of safer nanomaterials for water quality monitoring and remediation technologies. Hence, all data from this work were annotated and integrated into the NanoCommons Knowledge Base, connecting the experimental data to nanoinformatics platforms under the FAIR data principles and making them interoperable with similar datasets.

Individual and combined effects of zinc, cadmium and copper on the marine amphipod Allorchestes compressa

1988 ◽  
Vol 39 (1) ◽  
pp. 33 ◽  
Author(s):  
M Ahsanullah ◽  
MC Mobley ◽  
P Rankin
Keyword(s):  
Acute Toxicity ◽  
Combined Effects ◽  
Toxic Unit ◽  
Similar Action ◽  
Zinc Cadmium ◽  
Action Model ◽  
Marine Amphipod ◽  
Action Models

The acute toxicity of zinc, cadmium and copper to A. compressa was assessed in single, paired and triad combinations. Copper was 1.6 times more toxic than cadmium and 4 times more toxic than zinc. When tested in combinations of paired metals, independent dissimilar and simple similar action models, both of which are non-interactive in their classification, were rejected. In one case, the expected mortalities were lower (antagonism) which suggested that paired metals acted interactively. For the combination of three metals, the mortalities were predictable by the simple similar action model (non- interactive). Except for the Zn-Cd combination, the toxic unit concept underestimated the expected mortalities in the test combinations.

Modeling and Evaluation of Centrifugal Compressor Performance Variations Using Probabilistic Analysis

2005 ◽  
Author(s):  
Joseph Tecza ◽  
Peter Menegay ◽  
Jay Koch
Keyword(s):  
Response Surface ◽  
Probabilistic Analysis ◽  
Probability Distributions ◽  
Response Surfaces ◽  
Monte Carlo Integration ◽  
Surface Models ◽  
Dimensional Variation ◽  
Key Variables ◽  
Compressor Performance ◽  
Performance Variations

This paper presents a methodology for analyzing the variation in compressor stage performance due to component dimensional variations for a range of flows, speeds, gas compositions and scale factors. Due to the large number of input parameters involved, a Design of Experiments (DOE) approach was used to develop key variables, and to develop response surface models of head coefficient and efficiency in terms of these key variables. These response surface-based performance models then are used for a probabilistic analysis of head coefficient and efficiency as functions of dimensional variations, for a range of compressor sizes. The variations in dimensions are expressed as probability distributions and evaluated using a Monte-Carlo integration technique. The techniques for developing the response surfaces and performing the probabilistic analysis are described, as are methods for evaluating both the effects of dimensional variation on performance and for evaluating how much dimensional variation can be tolerated before the variation exceeds established limits.

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