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Results 351 - 400 of 1528
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Wang Nina Ching Yi - - 2012
Hazard identification and dose-response assessment for chemicals of concern found in various environmental media are typically based on epidemiological and/or animal toxicity data. However, human health risk assessments are often requested for many compounds found at contaminated sites throughout the US that have limited or no available toxicity information from ...
Maranghi Francesca - - 2012
Puberty is a process regulated by the endocrine system which physiological onset is poorly understood. Factors potentially leading to the disruption of this system may seriously affect the reproductive function development. Altered puberty onset can be an unspecific consequence of general toxicity in juvenile rodents; however, several toxicological studies indicate ...
Larsson Maria - - 2012
In the present study, relative potency factors (REPs) of 16 individual polycyclic aromatic hydrocarbons (PAHs) were investigated using the H4IIE-luc bioassay. Exposure time-dependent effects on the REPs were examined using 24, 48, and 72 h of exposure. Seven different mixtures of PAHs were tested for additivity at an exposure time of ...
Dulin Fabienne - - 2012
The widespread use of different pesticides generates adverse effects on non target organisms like honeybees. Organophosphorous and carbamates kill honeybees through the inactivation of acetylcholinesterase (AChE), thereby interfering with nerve signaling and function. For this class of pesticides, it is fundamental to understand the relationship between their structures and the ...
Audebert M - - 2012
Polycyclic Aromatic Hydrocarbons (PAHs) constitute a family of over one hundred compounds and can generally be found in complex mixtures. PAHs metabolites cause DNA damage which can lead to the development of carcinogenesis. Toxicity assessment of PAH complex mixtures is currently expressed in terms of toxic equivalents, based on Toxicity ...
Bhattacharjee Apurba K - - 2012
We earlier reported an in silico pharmacophore model for reactivation of oximes to tabun-inhibited AChE. Since DFP (diisopropylfluorophosphate) like tabun is a G-agent simulator, we utilized the model as a rational strategy to discover non-oxime reactivators of DFP-inhibited AChE in this study. The phramacophore was used for virtual screening of ...
Zhang Jing - - 2012
Recent toxicity studies on ionic liquids (ILs) are challenging their postulation as green solvents. Previous reports on mixtures containing ILs make it urgent to reveal the responsible components for the toxicity interactions. For that purpose, eight ILs, four consisting of 1-ethyl-3-methylimidazolium ([emim]) and the others of 1-butyl-3-methylimidazolium ([bmim]), were selected ...
Combes Robert D - - 2012
The principles and uses of (Q)SAR models and expert systems for predicting toxicity and the biotransformation of foreign chemicals (xenobiotics) are described and illustrated for some key toxicity endpoints, with examples from the published literature. The advantages and disadvantages of the methods and issues concerned with their validation, acceptance and ...
Neurath Markus F - - 2012
Background/Aims: Inflammatory bowel diseases (IBD) are chronic relapsing diseases of unknown origin. In spite of improved options for therapy, many patients with IBD have an impaired quality of life and require hospitalization or surgery. Animal models of IBD might help to obtain new insights into the pathogenesis of these diseases ...
Thai Khac-Minh - - 2012
Benzo[c]phenanthridine (BCP) derivatives were identified as topoisomerase I (TOP-I) targeting agents with pronounced antitumor activity. In this study, a support vector machine model was performed on a series of 73 analogues to classify BCP derivatives according to TOP-I inhibitory activity. The best SVM model with total accuracy of 93% for ...
Xu Tianlei - - 2012
Public resources of chemical compound are in a rapid growth both in quantity and the types of data-representation. To comprehensively understand the relationship between the intrinsic features of chemical compounds and protein targets is an essential task to evaluate potential protein-binding function for virtual drug screening. In previous studies, correlations ...
Ichiji Kei K Graduate School of Engineering, Tohoku University, Sendai, Japan. - - 2012
We develop a new prediction method of respiratory motion for accurate dynamic radiotherapy, called tumor following radiotherapy. The method is based on a time-variant seasonal autoregressive (TVSAR) model and extended to further capture time-variant and complex nature of various respiratory patterns. The extended TVSAR can represent not only the conventional ...
Sverdlova Nina S - - 2012
Various parts of the respiratory system play an important role in temperature control in birds. We create a simplified computational fluid dynamics (CFD) model of heat exchange in the trachea and air sacs of the domestic fowl (Gallus domesticus) in order to investigate the boundary conditions for the convective and ...
Casciano Daniel A - - 2012
Traditional toxicological tests generally provide descriptive information regarding the potential toxicity of chemicals, drugs and physical agents and are limited in their ability to assess risk to humans because they use model systems that are nonhuman in origin. Upon completion of the sequencing of the human genome, new tools were ...
Lipscomb John C - - 2012
Physiologically-based pharmacokinetic (PBPK) modeling offers a scientifically-sound framework for integrating mechanistic data on absorption, distribution, metabolism and elimination to predict the time-course of parent chemical, metabolite(s) or biomarkers in the exposed organism. A major advantage of PBPK models is their ability to forecast the impact of specific mechanistic processes and ...
Benner Steven A SA Foundation for Applied Molecular Evolution, Gainesville, Florida 32601, USA. - - 2012
No community-accepted scientific methods are available today to guide studies on what role RNA played in the origin and early evolution of life on Earth. Further, a definition-theory for life is needed to develop hypotheses relating to the "RNA First" model for the origin of life. Four approaches are currently ...
Thai Khac-Minh - - 2012
Benzo[<em>c</em>]phenanthridine (BCP) derivatives were identified as topoisomerase I (TOP-I) targeting agents with pronounced antitumor activity. In this study, hologram-QSAR, 2D-QSAR and 3D-QSAR models were developed for BCPs on topoisomerase I inbibitory activity and cytotoxicity against seven tumor cell lines including RPMI8402, CPT-K5, P388, CPT45, KB3-1, KBV-1and KBH5.0. The hologram, 2D, ...
Roy K - - 2012
Modern industrialisation has led to the production of millions of toxic chemicals having hazardous effects on the ecosystem. It is impracticable to determine the toxic potential of a large number of chemicals in animal models, making the use of quantitative structure-toxicity relationship (QSTR) models an alternative strategy for toxicity prediction. ...
McNally Kevin - - 2012
There are numerous biomonitoring programs, both recent and ongoing, to evaluate environmental exposure of humans to chemicals. Due to the lack of exposure and kinetic data, the correlation of biomarker levels with exposure concentrations leads to difficulty in utilizing biomonitoring data for biological guidance values. Exposure reconstruction or reverse dosimetry ...
Swarnkar V V School of ITEE, The University of Queensland, 4072, Australia. - - 2012
Cough is the most common symptom of several respiratory diseases. It is a defense mechanism of the body to clear the respiratory tract from foreign materials inhaled accidentally or produced internally by infections. The identification of wet and dry cough is an important clinical finding, aiding in the differential diagnosis. ...
Lundblad Lennart K A - - 2012
Airways hyperresponsiveness (AHR) is frequently a primary outcome in mouse models of asthma. There are, however, a number of variables that may affect the outcome of such measurements and the interpretation of the results. This article highlights issues that should be kept in mind when designing experiments using AHR as ...
Rutherford Grant - - 2012
This work uses agent-based modelling (ABM) to simulate sexually transmitted infection (STIs) spread within a population of 1000 agents over a 10-year period, as a preliminary investigation of the suitability of ABM methodology to simulate STI spread. The work contrasts compartmentalized mathematical models that fail to account for individual agents, ...
Chiew Yeong Shiong - - 2012
Mechanical ventilation (MV) is the primary form of support for acute respiratory distress syndrome (ARDS) patients. However, intra- and inter- patient-variability reduce the efficacy of general protocols. Model-based approaches to guide MV can be patient-specific. A physiological relevant minimal model and its patient-specific performance are tested to see if it ...
Videlier Benjamin B UJF-Grenoble 1, CNRS, TIMC-IMAG UMR 5525, PRETA Team, Grenoble, F-38041, - - 2012
We investigate Respiratory Inductive Plethysmography (RIP) to estimate cardiac activity from thoracic volume variations and study cardio-respiratory interactions. The objective of the present study is to evaluate the ability of RIP to monitor stroke volume (SV) variations, with reference to impedance cardiography (IMP). Five healthy volunteers in seated and supine ...
Mori Masahiko - - 2012
Class I HLA's polymorphism has hampered CTL epitope mapping with laborious experiments. Objectives are 1) to evaluate the novel in silico model in predicting previously reported epitopes in comparison with existing program, and 2) to apply the model to predict optimal epitopes with HLA using experimental results. We have developed ...
Ling Tristan - - 2012
Significant amounts of medical data are being archived, in the hope that they can be analysed and provide insight. A critical problem with analysing such data is the amount of existing knowledge required to produce effective results. This study tests a method that seeks to overcome these problems with analysis, ...
Lee Chia-Lin - - 2012
In a structure-activity relationship (SAR) study, 3-methoxy-1,4-phenanthrenequinones, calanquinone A (6a), denbinobin (6b), 5-OAc-calanquinone A (7a) and 5-OAc-denbinobin (7b), have significantly promising cytotoxicity against various human cancer cell lines (IC(50) 0.08-1.66 µg/mL). Moreover, we also established a superior pharmacophore model for cytotoxicity (r = 0.931) containing three hydrogen bond acceptors (HBA1, ...
Robles-Rubio Carlos A CA Department of Biomedical Engineering, McGill University, Montreal QC, H3A 2B4, Canada. - - 2012
The typical approach for analysis of respiratory records consists of detection of respiratory pauses and elimination of segments corrupted by movement artifacts. This is motivated by established rules used for manual scoring of respiratory events, which focus on pause segmentation and do not define criteria to identify breathing segments. With ...
O'Connor Russell - - 2012
Data-driven computational neural network models have been used to study mechanisms for generating the motor patterns for breathing and breathing related behaviors such as coughing. These models have commonly been evaluated in open loop conditions or with feedback of lung volume simply represented as a filtered version of phrenic motor ...
Kumar Mahto Sanjeev S Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa 32000, - - 2012
Our current understanding of respiratory physiology and pathophysiological mechanisms of lung diseases is often limited by challenges in developing in vitro models faithful to the respiratory environment, both in cellular structure and physiological function. The recent establishment and adaptation of microfluidic-based in vitro devices (μFIVDs) of lung airways have enabled ...
Ruiz Patricia - - 2012
Predicting toxicity quantitatively, using Quantitative Structure Activity Relationships (QSAR), has matured over recent years to the point that the predictions can be used to help identify missing comparison values in a substance's database. In this manuscript we investigate using the lethal dose that kills fifty percent of a test population ...
Kumar Rakesh K - - 2012
Whether mouse models of chronic asthma can be used to investigate the relationship between airway inflammation/remodeling and airway hyper-responsiveness (AHR) is a vexed question. It raises issues about the extent to which such models replicate key features of the human disease. Here, we review some of the characteristic pathological features ...
Goeminne Pieter C - - 2012
Chronic pulmonary infection is the hallmark of cystic fibrosis lung disease. Searching for faster and easier screening may lead to faster diagnosis and treatment of Pseudomonas aeruginosa (P. aeruginosa). Our aim was to analyze and build a model to predict the presence of P. aeruginosa in sputa. Sputa from 28 ...
Diekman Casey O CO Mathematical Biosciences Institute, The Ohio State University, Columbus, OH 43210, USA. - - 2012
We introduce a closed-loop model of respiratory control incorporating a conductance-based central pattern generator (CPG), low-pass filtering of CPG output by the respiratory musculature, gas exchange in the lung, metabolic oxygen demand, and chemosensation. The CPG incorporates Butera, Rinzel and Smith (BRS)'s (1999) conditional pacemaker model. BRS model cells can ...
Judson Richard S - - 2012
Computational toxicology combines data from high-throughput test methods, chemical structure analyses and other biological domains (e.g., genes, proteins, cells, tissues) with the goals of predicting and understanding the underlying mechanistic causes of chemical toxicity and for predicting toxicity of new chemicals and products. A key feature of such approaches is ...
Bates Jason H T - - 2011
The mechanical impedance of the respiratory system defines the pressure profile required to drive a unit of oscillatory flow into the lungs. Impedance is a function of oscillation frequency, and is measured using the forced oscillation technique. Digital signal processing methods, most notably the Fourier transform, are used to calculate ...
Knudsen Lars L Institute of Functional and Applied Anatomy , Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover , Germany - - 2011
Stereology provides a set of methods that are appropriate for a microscopy-based quantitative assessment of lung structure. In general, the aim of stereology is to obtain information on three-dimensional structures from two-dimensional sections of these structures. The inherent impartiality of stereological principles is critical in order to meet the requirements ...
Mehta Sumi - - 2013
Acute lower respiratory infections (ALRI) account for nearly one fifth of mortality in young children worldwide and have been associated with exposures to indoor and outdoor sources of combustion-derived air pollution. A systematic review was conducted to identify relevant articles on air pollution and ALRI in children. Using a Bayesian ...
Suki Béla - - 2011
Complex biological systems operate under non-equilibrium conditions and exhibit emergent properties associated with correlated spatial and temporal structures. These properties may be individually unpredictable, but tend to be governed by power-law probability distributions and/or correlation. This article reviews the concepts that are invoked in the treatment of complex systems through ...
Ritter Kerry J - - 2011
Toxicity-based sediment quality guidelines (SQGs) are often used to assess the potential of sediment contamination to adversely affect benthic macrofauna, yet the correspondence of these guidelines to benthic community condition is poorly documented. This study compares the performance of five toxicity-based SQG approaches to a new benthos-based SQG approach relative ...
Lebeau Marc A - - 2011
Segmental analysis of hair for drugs, metabolites, and poisons has been widely reported in the scientific literature over the past two decades. Two fundamental assumptions in interpreting results of such analyses are (1) an average linear growth rate of head hair of 1cm/month and (2) that sample collections occur with ...
Becker William J - - 2011
Previous research pertaining to job performance and voluntary turnover has been guided by 2 distinct theoretical perspectives. First, the push-pull model proposes that there is a quadratic or curvilinear relationship existing between these 2 variables. Second, the unfolding model of turnover posits that turnover is a dynamic process and that ...
Ionescu C M - - 2011
The self similar branching arrangement of the airways makes the respiratory system an ideal candidate for the application of fractional calculus theory. The fractal geometry is typically characterized by a recurrent structure. This study investigates the identification of a model for the respiratory tree by means of its electrical equivalent ...
Valko Michal M INRIA Lille - Nord Europe, SequeL project, 40 avenue Halley, Villeneuve d'Ascq, France, - - 2011
In this paper, we consider the problem of conditional anomaly detection that aims to identify data instances with an unusual response or a class label. We develop a new non-parametric approach for conditional anomaly detection based on the soft harmonic solution, with which we estimate the confidence of the label ...
Sussman R W RW Department of Anthropology, Washington University, St. Louis, MO 63130, USA. - - 2011
This is a reply to Richard Lawler's commentary on our previous work [Lawler, 2011; this issue] in which he develops a set of operational models to test socioecological theories of the evolutionary importance of feeding competition. We strongly agree that we need to critically re-evaluate the basic assumptions of all ...
Kuperman M N - - 2010
In this work, we present a model based on a competitive dynamics that intends to imitate the processes leading to some characteristics of the geopolitical division. The model departs from very simple principles of geopolitical theory and geometrical considerations, but succeeds in explaining the general features related to the actual ...
Field Andy P - - 2010
Clinical and experimental theories assume that processing biases in attention and interpretation are a causal mechanism through which anxiety develops. Despite growing evidence that these processing biases are present in children and, therefore, develop long before adulthood, these theories ignore the potential role of child development. This review attempts to ...
Francis Jill J JJ Health Services Research Unit, University of Aberdeen, Aberdeen, UK. - - 2010
In interview studies, sample size is often justified by interviewing participants until reaching 'data saturation'. However, there is no agreed method of establishing this. We propose principles for deciding saturation in theory-based interview studies (where conceptual categories are pre-established by existing theory). First, specify a minimum sample size for initial ...
Lombrozo Tania - - 2010
Both philosophers and psychologists have argued for the existence of distinct kinds of explanations, including teleological explanations that cite functions or goals, and mechanistic explanations that cite causal mechanisms. Theories of causation, in contrast, have generally been unitary, with dominant theories focusing either on counterfactual dependence or on physical connections. ...
Doane Tennyson L - - 2010
Electromigration of nanoparticles (NPs) is relevant to many technological and biological applications. We correlate the experimentally observed electromigration of Au NPs with a closed-form theoretical model that furnishes key NP characteristics, including the previously unknown values of Au NP core ζ-potential, PEG-corona permeability, and particle-hydrogel friction coefficient. More generally, the ...
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