The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Edward J. Calabrese - One of the best experts on this subject based on the ideXlab platform.
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the linear no threshold lnt dose Response Model a comprehensive assessment of its historical and scientific foundations
Chemico-Biological Interactions, 2019Co-Authors: Edward J. CalabreseAbstract:The linear no-threshold (LNT) single-hit (SH) dose Response Model for cancer risk assessment is comprehensively assessed with respect to its historical foundations. This paper also examines how mistakes, ideological biases, and scientific misconduct by key scientists affected the acceptance, validity, and applications of the LNT Model for cancer risk assessment. In addition, the analysis demonstrates that the LNT single-hit Model was inappropriately adopted for governmental risk assessment, regulatory policy, practices, and for risk communication.
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paradigm lost paradigm found the re emergence of hormesis as a fundamental dose Response Model in the toxicological sciences
Environmental Pollution, 2005Co-Authors: Edward J. CalabreseAbstract:Abstract This paper provides an assessment of the toxicological basis of the hormetic dose–Response relationship including issues relating to its reproducibility, frequency, and generalizability across biological Models, endpoints measured and chemical class/physical stressors and implications for risk assessment. The quantitative features of the hormetic dose Response are described and placed within toxicological context that considers study design, temporal assessment, mechanism, and experimental Model/population heterogeneity. Particular emphasis is placed on an historical evaluation of why the field of toxicology rejected hormesis in favor of dose Response Models such as the threshold Model for assessing non-carcinogens and linear no threshold (LNT) Models for assessing carcinogens. The paper argues that such decisions were principally based on complex historical factors that emerged from the intense and protracted conflict between what is now called traditional medicine and homeopathy and the overly dominating influence of regulatory agencies on the toxicological intellectual agenda. Such regulatory agency influence emphasized hazard/risk assessment goals such as the derivation of no observed adverse effect levels (NOAELs) and the lowest observed adverse effect levels (LOAELs) which were derived principally from high dose studies using few doses, a feature which restricted perceptions and distorted judgments of several generations of toxicologists concerning the nature of the dose–Response continuum. Such historical and technical blind spots lead the field of toxicology to not only reject an established dose–Response Model (hormesis), but also the Model that was more common and fundamental than those that the field accepted.
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hormesis from marginalization to mainstream a case for hormesis as the default dose Response Model in risk assessment
Toxicology and Applied Pharmacology, 2004Co-Authors: Edward J. CalabreseAbstract:Abstract The paper provides an account of how the hormetic dose Response has emerged in recent years as a serious dose-Response Model in toxicology and risk assessment after decades of extreme marginalization. In addition to providing the toxicological basis of this dose-Response revival, the paper reexamines the concept of a default dose Model in toxicology and risk assessment and makes the argument that the hormetic Model satisfies criteria (e.g., generalizability, frequency, application to risk assessment endpoints, false positive/negative potential, requirements for hazard assessment, reliability of estimating risks, capacity for validation of risk estimates, public health implications of risk estimates) for such a default Model better than its chief competitors, the threshold and linear at low dose Models. The selection of the hormetic Model as the default Model in risk assessment for noncarcinogens and specifically for carcinogens would have a profound impact on the practice of risk assessment and its societal implications.
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the hormetic dose Response Model is more common than the threshold Model in toxicology
Toxicological Sciences, 2003Co-Authors: Edward J. Calabrese, Linda A BaldwinAbstract:The threshold dose-Response Model is widely viewed as the most dominant Model in toxicology. The present study was designed to test the validity of the threshold Model by assessing the Responses of doses below the toxicological NOAEL (no observed adverse effect level) in relationship to the control Response (i.e., unexposed group). Nearly 1800 doses below the NOAEL, from 664 doseResponse relationships derived from a previously published database that satisfied a priori entry criteria, were evaluated. While the threshold Model predicts a 1:1 ratio of Responses “greater than” to “less than” the control Response (i.e., a random distribution), a 2.5:1 ratio (i.e., 1171:464) was observed, reflecting 31% more Responses above the control value than expected (p < 0.0001). The mean Response (calculated as % control Response) of doses below the NOAEL was 115.0% 1.5 standard error of the mean (SEM). These findings challenge the long-standing belief in the primacy of the threshold Model in toxicology (and other areas of biology involving dose-Response relationships) and provide strong support for the hormetic-like biphasic dose-Response Model characterized by a low-dose stimulation and a high-dose inhibition. These findings may affect numerous aspects of toxicological and biological/ biomedical research related to dose-Response relationships, including study design, risk assessment, as well as chemotherapeutic strategies.
Sharron J Lennon - One of the best experts on this subject based on the ideXlab platform.
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effects of reputation and website quality on online consumers emotion perceived risk and purchase intention based on the stimulus organism Response Model
Journal of Research in Interactive Marketing, 2013Co-Authors: Jiyoung Kim, Sharron J LennonAbstract:Purpose – This research extends Mehrabian and Russell's Stimulus‐Organism‐Response Model to include both external (i.e. reputation) and internal source of information (i.e. website quality) as stimuli which affect consumers' Response systems. The purpose of this paper is to test a more comprehensive Model consisting of reputation and website quality (stimuli), cognition and emotion (organism) and purchase intention (Response).Design/methodology/approach – In total, 219 usable questionnaires were obtained at a large Midwestern university through online survey. Structural equation Modeling (SEM) was employed for data analyses.Findings – Reputation had a significant positive effect on consumers' emotion and significant negative effect on perceived risk. All four website quality dimensions had significant negative effects on perceived risk and significant positive effects on emotion, except for customer service. Perceived risk had a significant negative effect on consumers' emotion, and both perceived risk an...
Alan Murray - One of the best experts on this subject based on the ideXlab platform.
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an implementation of a spike Response Model with escape noise using an avalanche diode
IEEE Transactions on Biomedical Circuits and Systems, 2011Co-Authors: Thomas Clayton, Katherine Cameron, Nancy Sabatier, Edoardo Charbon, Robert Henderson, Gareth Leng, Alan MurrayAbstract:This paper introduces a novel probabilistic spike-Response Model through the combination of avalanche diode-generated Poisson distributed noise, and a standard exponential decay-based spike-Response curve. The noise source, which is derived from a 0.35-μm single-photon avalanche diode (kept in the dark), was tested experimentally to verify its characteristics, before being combined with a field-programmable gate-array implementation of a spike-Response Model. This simple Model was then analyzed, and shown to reproduce seven of eight behaviors recorded during an extensive study of the ventral medial hypothalamic (VMH) region of the brain. It is thought that many of the cell types found within the VMH are fed from a tonic noise synaptic input, where the patterns generated are a product of their spike Response and not their interconnection. This paper shows how this tonic noise source can be Modelled, and due to the independent nature of the noise sources, provides an avenue for the exploration of networks of noise-fueled neurons, which play a significant role in pattern generation within the brain.
Jiyoung Kim - One of the best experts on this subject based on the ideXlab platform.
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effects of reputation and website quality on online consumers emotion perceived risk and purchase intention based on the stimulus organism Response Model
Journal of Research in Interactive Marketing, 2013Co-Authors: Jiyoung Kim, Sharron J LennonAbstract:Purpose – This research extends Mehrabian and Russell's Stimulus‐Organism‐Response Model to include both external (i.e. reputation) and internal source of information (i.e. website quality) as stimuli which affect consumers' Response systems. The purpose of this paper is to test a more comprehensive Model consisting of reputation and website quality (stimuli), cognition and emotion (organism) and purchase intention (Response).Design/methodology/approach – In total, 219 usable questionnaires were obtained at a large Midwestern university through online survey. Structural equation Modeling (SEM) was employed for data analyses.Findings – Reputation had a significant positive effect on consumers' emotion and significant negative effect on perceived risk. All four website quality dimensions had significant negative effects on perceived risk and significant positive effects on emotion, except for customer service. Perceived risk had a significant negative effect on consumers' emotion, and both perceived risk an...
Thomas Clayton - One of the best experts on this subject based on the ideXlab platform.
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an implementation of a spike Response Model with escape noise using an avalanche diode
IEEE Transactions on Biomedical Circuits and Systems, 2011Co-Authors: Thomas Clayton, Katherine Cameron, Nancy Sabatier, Edoardo Charbon, Robert Henderson, Gareth Leng, Alan MurrayAbstract:This paper introduces a novel probabilistic spike-Response Model through the combination of avalanche diode-generated Poisson distributed noise, and a standard exponential decay-based spike-Response curve. The noise source, which is derived from a 0.35-μm single-photon avalanche diode (kept in the dark), was tested experimentally to verify its characteristics, before being combined with a field-programmable gate-array implementation of a spike-Response Model. This simple Model was then analyzed, and shown to reproduce seven of eight behaviors recorded during an extensive study of the ventral medial hypothalamic (VMH) region of the brain. It is thought that many of the cell types found within the VMH are fed from a tonic noise synaptic input, where the patterns generated are a product of their spike Response and not their interconnection. This paper shows how this tonic noise source can be Modelled, and due to the independent nature of the noise sources, provides an avenue for the exploration of networks of noise-fueled neurons, which play a significant role in pattern generation within the brain.
