Molecular Modeling on Berberine Derivatives toward BuChE: An Integrated Study with Quantitative Structure-Activity Relationships Models, Molecular Docking, and Molecular Dynamics Simulations.

PubMed

Fang, Jiansong; Pang, Xiaocong; Wu, Ping; Yan, Rong; Gao, Li; Li, Chao; Lian, Wenwen; Wang, Qi; Liu, Ai-lin; Du, Guan-hua

2016-05-01

A dataset of 67 berberine derivatives for the inhibition of butyrylcholinesterase (BuChE) was studied based on the combination of quantitative structure-activity relationships models, molecular docking, and molecular dynamics methods. First, a series of berberine derivatives were reported, and their inhibitory activities toward butyrylcholinesterase (BuChE) were evaluated. By 2D- quantitative structure-activity relationships studies, the best model built by partial least-square had a conventional correlation coefficient of the training set (R(2)) of 0.883, a cross-validation correlation coefficient (Qcv2) of 0.777, and a conventional correlation coefficient of the test set (Rpred2) of 0.775. The model was also confirmed by Y-randomization examination. In addition, the molecular docking and molecular dynamics simulation were performed to better elucidate the inhibitory mechanism of three typical berberine derivatives (berberine, C2, and C55) toward BuChE. The predicted binding free energy results were consistent with the experimental data and showed that the van der Waals energy term (ΔEvdw) difference played the most important role in differentiating the activity among the three inhibitors (berberine, C2, and C55). The developed quantitative structure-activity relationships models provide details on the fine relationship linking structure and activity and offer clues for structural modifications, and the molecular simulation helps to understand the inhibitory mechanism of the three typical inhibitors. In conclusion, the results of this study provide useful clues for new drug design and discovery of BuChE inhibitors from berberine derivatives. © 2015 John Wiley & Sons A/S.

Toxicity challenges in environmental chemicals: Prediction of human plasma protein binding through quantitative structure-activity relationship (QSAR) models

EPA Science Inventory

The present study explores the merit of utilizing available pharmaceutical data to construct a quantitative structure-activity relationship (QSAR) for prediction of the fraction of a chemical unbound to plasma protein (Fub) in environmentally relevant compounds. Independent model...

A reverse pathway? Actual and perceived skill proficiency and physical activity.

PubMed

Barnett, Lisa M; Morgan, Philip J; Van Beurden, Eric; Ball, Kylie; Lubans, David R

2011-05-01

Motor skills are considered a prerequisite to physical activity, yet the relationship may be reciprocal and perceived sports competence might mediate associations. In 2006/2007, 215 adolescents completed motor skill proficiency (Get Skilled Get Active), perceived sport competence (Physical Self-Perception Profile) and physical activity assessments (Adolescent Physical Activity Recall Questionnaire) as part of the Physical Activity and Skills Study. Using AMOS (Version 7.0), reciprocal relationships were examined between motor skill (object control and locomotor) and moderate to vigorous physical activity (MVPA). Both models were then run in different versions to understand the role of perceived sports competence as a potential mediator. Mean age was 16.4 yr (SD=0.6), 51.6% (111/215) were females. A reciprocal relationship between object control and MVPA and a one-way relationship from MVPA to locomotor skill was found. When perceived sports competence was examined as a mediator, the best-fitting model versions explained 16% (R=0.16) MVPA variation, and 30% object control (R=0.30), and 12% locomotor skill variation (R=0.12) (reverse relationship). Perceived sports competence partially mediates the relationship between object control proficiency and physical activity for both directions and fully mediates the relationship between physical activity and locomotor skill; but only when locomotor skill is the outcome. If the relationship between object control skill and physical activity is viewed as a "positive feedback loop," skill development and increasing physical activity should simultaneously be targeted in physical activity interventions. Increasing perceived sport competence should also be an intervention focus. © 2011 by the American College of Sports Medicine

THE PRACTICE OF STRUCTURE ACTIVITY RELATIONSHIPS (SAR) IN TOXICOLOGY

EPA Science Inventory

Both qualitative and quantitative modeling methods relating chemical structure to biological activity, called structure-activity relationship analyses or SAR, are applied to the prediction and characterization of chemical toxicity. This minireview will discuss some generic issue...

Development of a Conceptual Model for Smoking Cessation: Physical Activity, Neurocognition, and Executive Functioning.

PubMed

Loprinzi, Paul D; Herod, Skyla M; Walker, Jerome F; Cardinal, Bradley J; Mahoney, Sara E; Kane, Christy

2015-01-01

Considerable research has shown adverse neurobiological effects of chronic alcohol use, including long-term and potentially permanent changes in the structure and function of the brain; however, much less is known about the neurobiological consequences of chronic smoking, as it has largely been ignored until recently. In this article, we present a conceptual model proposing the effects of smoking on neurocognition and the role that physical activity may play in this relationship as well as its role in smoking cessation. Pertinent published peer-reviewed articles deposited in PubMed delineating the pathways in the proposed model were reviewed. The proposed model, which is supported by emerging research, demonstrates a bidirectional relationship between smoking and executive functioning. In support of our conceptual model, physical activity may moderate this relationship and indirectly influence smoking behavior through physical activity-induced changes in executive functioning. Our model may have implications for aiding smoking cessation efforts through the promotion of physical activity as a mechanism for preventing smoking-induced deficits in neurocognition and executive function.

Testing Theory of Planned Behavior and Neo-Socioanalytic Theory models of trait activity, industriousness, exercise social cognitions, exercise intentions, and physical activity in a representative U.S. sample.

PubMed

Vo, Phuong T; Bogg, Tim

2015-01-01

Prior research identified assorted relations between trait and social cognition models of personality and engagement in physical activity. Using a representative U.S. sample (N = 957), the goal of the present study was to test two alternative structural models of the relationships among the extraversion-related facet of activity, the conscientiousness-related facet of industriousness, social cognitions from the Theory of Planned Behavior (perceived behavioral control, affective attitudes, subjective norms, intentions), Social Cognitive Theory (self-efficacy, outcome expectancies), and the Transtheoretical Model (behavioral processes of change), and engagement in physical activity. Path analyses with bootstrapping procedures were used to model direct and indirect effects of trait and social cognition constructs on physical activity through two distinct frameworks - the Theory of Planned Behavior and Neo-Socioanalytic Theory. While both models showed good internal fit, comparative model information criteria showed the Theory-of-Planned-Behavior-informed model provided a better fit. In the model, social cognitions fully mediated the relationships from the activity facet and industriousness to intentions for and engagement in physical activity, such that the relationships were primarily maintained by positive affective evaluations, positive expected outcomes, and confidence in overcoming barriers related to physical activity engagement. The resultant model - termed the Disposition-Belief-Motivation model- is proposed as a useful framework for organizing and integrating personality trait facets and social cognitions from various theoretical perspectives to investigate the expression of health-related behaviors, such as physical activity. Moreover, the results are discussed in terms of extending the application of the Disposition-Belief-Motivation model to longitudinal and intervention designs for physical activity engagement.

Hope-inspiring therapeutic relationships, professional expectations and social inclusion for young people with psychosis.

PubMed

Berry, Clio; Greenwood, Kathryn

2015-10-01

Personal recovery accounts suggest that a positive therapeutic relationship with an optimistic mental health professional may facilitate social inclusion. However, little empirical research has investigated the role of the therapeutic relationship in social outcomes or explored potential mechanisms of change within community psychosis care. This study investigated the direct predictive associations of the therapeutic relationship and professional expectancies for social inclusion and vocational activity for young people with psychosis, and indirect associations through hopefulness. Young people with psychosis and their main mental health professional (n=51 dyads) participated across two time points. Measures of therapeutic relationships, professional expectancies, and vocational activity were obtained at baseline. Measures of hopefulness, social inclusion and vocational activity were obtained at follow-up. Direct and indirect associations between variables were analysed using path modelling. Directed path models were consistent with a positive therapeutic relationship and positive professional expectancies predicting social inclusion and vocational activity through mediation by increased patient domain-specific hopefulness. The professional-rated therapeutic relationship more directly predicts change in vocational activity status. Change in vocational activity status predicts increased patient hopefulness. The therapeutic relationship between professionals and young people with psychosis appears hope-inspiring and important to patients' social inclusion and vocational outcomes. Vocational activity may produce reciprocal gains in hopefulness. Copyright © 2015 Elsevier B.V. All rights reserved.

3D-quantitative structure-activity relationship studies on benzothiadiazepine hydroxamates as inhibitors of tumor necrosis factor-alpha converting enzyme.

PubMed

Murumkar, Prashant R; Giridhar, Rajani; Yadav, Mange Ram

2008-04-01

A set of 29 benzothiadiazepine hydroxamates having selective tumor necrosis factor-alpha converting enzyme inhibitory activity were used to compare the quality and predictive power of 3D-quantitative structure-activity relationship, comparative molecular field analysis, and comparative molecular similarity indices models for the atom-based, centroid/atom-based, data-based, and docked conformer-based alignment. Removal of two outliers from the initial training set of molecules improved the predictivity of models. Among the 3D-quantitative structure-activity relationship models developed using the above four alignments, the database alignment provided the optimal predictive comparative molecular field analysis model for the training set with cross-validated r(2) (q(2)) = 0.510, non-cross-validated r(2) = 0.972, standard error of estimates (s) = 0.098, and F = 215.44 and the optimal comparative molecular similarity indices model with cross-validated r(2) (q(2)) = 0.556, non-cross-validated r(2) = 0.946, standard error of estimates (s) = 0.163, and F = 99.785. These models also showed the best test set prediction for six compounds with predictive r(2) values of 0.460 and 0.535, respectively. The contour maps obtained from 3D-quantitative structure-activity relationship studies were appraised for activity trends for the molecules analyzed. The comparative molecular similarity indices models exhibited good external predictivity as compared with that of comparative molecular field analysis models. The data generated from the present study helped us to further design and report some novel and potent tumor necrosis factor-alpha converting enzyme inhibitors.

Testing Theory of Planned Behavior and Neo-Socioanalytic Theory models of trait activity, industriousness, exercise social cognitions, exercise intentions, and physical activity in a representative U.S. sample

PubMed Central

Vo, Phuong T.; Bogg, Tim

2015-01-01

Prior research identified assorted relations between trait and social cognition models of personality and engagement in physical activity. Using a representative U.S. sample (N = 957), the goal of the present study was to test two alternative structural models of the relationships among the extraversion-related facet of activity, the conscientiousness-related facet of industriousness, social cognitions from the Theory of Planned Behavior (perceived behavioral control, affective attitudes, subjective norms, intentions), Social Cognitive Theory (self-efficacy, outcome expectancies), and the Transtheoretical Model (behavioral processes of change), and engagement in physical activity. Path analyses with bootstrapping procedures were used to model direct and indirect effects of trait and social cognition constructs on physical activity through two distinct frameworks – the Theory of Planned Behavior and Neo-Socioanalytic Theory. While both models showed good internal fit, comparative model information criteria showed the Theory-of-Planned-Behavior-informed model provided a better fit. In the model, social cognitions fully mediated the relationships from the activity facet and industriousness to intentions for and engagement in physical activity, such that the relationships were primarily maintained by positive affective evaluations, positive expected outcomes, and confidence in overcoming barriers related to physical activity engagement. The resultant model – termed the Disposition-Belief-Motivation model– is proposed as a useful framework for organizing and integrating personality trait facets and social cognitions from various theoretical perspectives to investigate the expression of health-related behaviors, such as physical activity. Moreover, the results are discussed in terms of extending the application of the Disposition-Belief-Motivation model to longitudinal and intervention designs for physical activity engagement. PMID:26300811

Moderators, mediators, and bidirectional relationships in the International Classification of Functioning, Disability and Health (ICF) framework: An empirical investigation using a longitudinal design and Structural Equation Modeling (SEM).

PubMed

Rouquette, Alexandra; Badley, Elizabeth M; Falissard, Bruno; Dub, Timothée; Leplege, Alain; Coste, Joël

2015-06-01

The International Classification of Functioning, Disability and Health (ICF) published in 2001 describes the consequences of health conditions with three components of impairments in body structures or functions, activity limitations and participation restrictions. Two of the new features of the conceptual model were the possibility of feedback effects between each ICF component and the introduction of contextual factors conceptualized as moderators of the relationship between the components. The aim of this longitudinal study is to provide empirical evidence of these two kinds of effect. Structural equation modeling was used to analyze data from a French population-based cohort of 548 patients with knee osteoarthritis recruited between April 2007 and March 2009 and followed for three years. Indicators of the body structure and function, activity and participation components of the ICF were derived from self-administered standardized instruments. The measurement model revealed four separate factors for body structures impairments, body functions impairments, activity limitations and participation restrictions. The classic sequence from body impairments to participation restrictions through activity limitations was found at each assessment time. Longitudinal study of the ICF component relationships showed a feedback pathway indicating that the level of participation restrictions at baseline was predictive of activity limitations three years later. Finally, the moderating role of personal (age, sex, mental health, etc.) and environmental factors (family relationships, mobility device use, etc.) was investigated. Three contextual factors (sex, family relationships and walking stick use) were found to be moderators for the relationship between the body impairments and the activity limitations components. Mental health was found to be a mediating factor of the effect of activity limitations on participation restrictions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparative Analysis of Predictive Models for Liver Toxicity Using ToxCast Assays and Quantitative Structure-Activity Relationships (MCBIOS)

EPA Science Inventory

Comparative Analysis of Predictive Models for Liver Toxicity Using ToxCast Assays and Quantitative Structure-Activity Relationships Jie Liu1,2, Richard Judson1, Matthew T. Martin1, Huixiao Hong3, Imran Shah1 1National Center for Computational Toxicology (NCCT), US EPA, RTP, NC...

Cookie-Ases: Interactive Models for Teaching Genotype-Phenotype Relationships

ERIC Educational Resources Information Center

Seipelt, Rebecca L.

2006-01-01

Several hands-on and wet laboratory activities have been proposed to model the genetic concepts of genotypes and phenotypes and their relationship. The exercise presented in this article is a novel, time effective, student-centered, role-playing activity in which students learn about the intricate connection between genotype and phenotype by…

Testing a Theoretical Model of Immigration Transition and Physical Activity.

PubMed

Chang, Sun Ju; Im, Eun-Ok

2015-01-01

The purposes of the study were to develop a theoretical model to explain the relationships between immigration transition and midlife women's physical activity and test the relationships among the major variables of the model. A theoretical model, which was developed based on transitions theory and the midlife women's attitudes toward physical activity theory, consists of 4 major variables, including length of stay in the United States, country of birth, level of acculturation, and midlife women's physical activity. To test the theoretical model, a secondary analysis with data from 127 Hispanic women and 123 non-Hispanic (NH) Asian women in a national Internet study was used. Among the major variables of the model, length of stay in the United States was negatively associated with physical activity in Hispanic women. Level of acculturation in NH Asian women was positively correlated with women's physical activity. Country of birth and level of acculturation were significant factors that influenced physical activity in both Hispanic and NH Asian women. The findings support the theoretical model that was developed to examine relationships between immigration transition and physical activity; it shows that immigration transition can play an essential role in influencing health behaviors of immigrant populations in the United States. The NH theoretical model can be widely used in nursing practice and research that focus on immigrant women and their health behaviors. Health care providers need to consider the influences of immigration transition to promote immigrant women's physical activity.

The relationship between particulate pollution levels in Australian cities, meteorology, and landscape fire activity detected from MODIS hotspots.

PubMed

Price, Owen F; Williamson, Grant J; Henderson, Sarah B; Johnston, Fay; Bowman, David M J S

2012-01-01

Smoke from bushfires is an emerging issue for fire managers because of increasing evidence for its public health effects. Development of forecasting models to predict future pollution levels based on the relationship between bushfire activity and current pollution levels would be a useful management tool. As a first step, we use daily thermal anomalies detected by the MODIS Active Fire Product (referred to as "hotspots"), pollution concentrations, and meteorological data for the years 2002 to 2008, to examine the statistical relationship between fire activity in the landscapes and pollution levels around Perth and Sydney, two large Australian cities. Resultant models were statistically significant, but differed in their goodness of fit and the distance at which the strength of the relationship was strongest. For Sydney, a univariate model for hotspot activity within 100 km explained 24% of variation in pollution levels, and the best model including atmospheric variables explained 56% of variation. For Perth, the best radius was 400 km, explaining only 7% of variation, while the model including atmospheric variables explained 31% of the variation. Pollution was higher when the atmosphere was more stable and in the presence of on-shore winds, whereas there was no effect of wind blowing from the fires toward the pollution monitors. Our analysis shows there is a good prospect for developing region-specific forecasting tools combining hotspot fire activity with meteorological data.

Relationship among Phosphorus Circulation Activity, Bacterial Biomass, pH, and Mineral Concentration in Agricultural Soil.

PubMed

Adhikari, Dinesh; Jiang, Tianyi; Kawagoe, Taiki; Kai, Takamitsu; Kubota, Kenzo; Araki, Kiwako S; Kubo, Motoki

2017-12-04

Improvement of phosphorus circulation in the soil is necessary to enhance phosphorus availability to plants. Phosphorus circulation activity is an index of soil's ability to supply soluble phosphorus from organic phosphorus in the soil solution. To understand the relationship among phosphorus circulation activity; bacterial biomass; pH; and Fe, Al, and Ca concentrations (described as mineral concentration in this paper) in agricultural soil, 232 soil samples from various agricultural fields were collected and analyzed. A weak relationship between phosphorus circulation activity and bacterial biomass was observed in all soil samples ( R ² = 0.25), and this relationship became significantly stronger at near-neutral pH (6.0-7.3; R ² = 0.67). No relationship between phosphorus circulation activity and bacterial biomass was observed at acidic (pH < 6.0) or alkaline (pH > 7.3) pH. A negative correlation between Fe and Al concentrations and phosphorus circulation activity was observed at acidic pH ( R ² = 0.72 and 0.73, respectively), as well as for Ca at alkaline pH ( R ² = 0.64). Therefore, bacterial biomass, pH, and mineral concentration should be considered together for activation of phosphorus circulation activity in the soil. A relationship model was proposed based on the effects of bacterial biomass and mineral concentration on phosphorus circulation activity. The suitable conditions of bacterial biomass, pH, and mineral concentration for phosphorus circulation activity could be estimated from the relationship model.

The effects of parental education and family income on mother-child relationships, father-child relationships, and family environments in the People's Republic of China.

PubMed

Zhang, Xiao

2012-12-01

Using a cross-sectional design with 407 Chinese children aged 3-5 years and their parents, this study examined the effects of socioeconomic status, specifically parents' education and family income, on the children's mother-child relationships, father-child relationships, and the social environment in their families. The results indicated that income negatively predicted conflict in father-child relationships and positively predicted family active-recreational environments. Income also positively predicted family cohesion among girls but not boys. Maternal education negatively predicted conflict in mother-child relationships and positively predicted closeness in mother-child and father-child relationships, family cohesion, and the intellectual-cultural and active-recreational environments in the family. Paternal education positively predicted family cohesion and intellectual-cultural and active-recreational environments. Income was found to partially mediate the effects of both maternal and paternal education on family active-recreational environments. Findings are discussed in the frameworks of the family stress model and the family investment model. © FPI, Inc.

Forecasting the Environmental Impacts of New Energetic Materials

DTIC Science & Technology

2010-11-30

Quantitative structure- activity relationships for chemical reductions of organic contaminants. Environmental Toxicology and Chemistry 22(8): 1733-1742. QSARs ...activity relationships [ QSARs ]) and the use of these properties to predict the chemical?s fate with multimedia assessment models. SERDP has recently...has several parts, including the prediction of chemical properties (e.g., with quantitative structure-activity relationships [ QSARs ]) and the use of

The Moderating Effect of Health-Improving Workplace Environment on Promoting Physical Activity in White-Collar Employees: A Multi-Site Longitudinal Study Using Multi-Level Structural Equation Modeling.

PubMed

Watanabe, Kazuhiro; Otsuka, Yasumasa; Shimazu, Akihito; Kawakami, Norito

2016-02-01

This longitudinal study aimed to investigate the moderating effect of health-improving workplace environment on relationships between physical activity, self-efficacy, and psychological distress. Data were collected from 16 worksites and 129 employees at two time-points. Health-improving workplace environment was measured using the Japanese version of the Environmental Assessment Tool. Physical activity, self-efficacy, and psychological distress were also measured. Multi-level structural equation modeling was used to investigate the moderating effect of health-improving workplace environment on relationships between psychological distress, self-efficacy, and physical activity. Psychological distress was negatively associated with physical activity via low self-efficacy. Physical activity was negatively related to psychological distress. Physical activity/fitness facilities in the work environment exaggerated the positive relationship between self-efficacy and physical activity. Physical activity/fitness facilities in the workplace may promote employees' physical activity.

lazar: a modular predictive toxicology framework

PubMed Central

Maunz, Andreas; Gütlein, Martin; Rautenberg, Micha; Vorgrimmler, David; Gebele, Denis; Helma, Christoph

2013-01-01

lazar (lazy structure–activity relationships) is a modular framework for predictive toxicology. Similar to the read across procedure in toxicological risk assessment, lazar creates local QSAR (quantitative structure–activity relationship) models for each compound to be predicted. Model developers can choose between a large variety of algorithms for descriptor calculation and selection, chemical similarity indices, and model building. This paper presents a high level description of the lazar framework and discusses the performance of example classification and regression models. PMID:23761761

Investigating the Relationship among Extracurricular Activities, Learning Approach and Academic Outcomes: A Case Study

ERIC Educational Resources Information Center

Chan, Yiu-Kong

2016-01-01

Learning effectiveness requires an understanding of the relationship among extracurricular activities, learning approach and academic performance and, it is argued, this helps educators develop techniques designed to enrich learning effectiveness. Biggs' Presage-Process-Product model on student learning has identified the relationship among…

On the potential for using immersive virtual environments to support laboratory experiment contextualisation

NASA Astrophysics Data System (ADS)

Machet, Tania; Lowe, David; Gütl, Christian

2012-12-01

This paper explores the hypothesis that embedding a laboratory activity into a virtual environment can provide a richer experimental context and hence improve the understanding of the relationship between a theoretical model and the real world, particularly in terms of the model's strengths and weaknesses. While an identified learning objective of laboratories is to support the understanding of the relationship between models and reality, the paper illustrates that this understanding is hindered by inherently limited experiments and that there is scope for improvement. Despite the contextualisation of learning activities having been shown to support learning objectives in many fields, there is traditionally little contextual information presented during laboratory experimentation. The paper argues that the enhancing laboratory activity with contextual information affords an opportunity to improve students' understanding of the relationship between the theoretical model and the experiment (which is effectively a proxy for the complex real world), thereby improving their understanding of the relationship between the model and reality. The authors propose that these improvements can be achieved by setting remote laboratories within context-rich virtual worlds.

Quantitative structure-activity relationship study of P2X7 receptor inhibitors using combination of principal component analysis and artificial intelligence methods.

PubMed

Ahmadi, Mehdi; Shahlaei, Mohsen

2015-01-01

P2X7 antagonist activity for a set of 49 molecules of the P2X7 receptor antagonists, derivatives of purine, was modeled with the aid of chemometric and artificial intelligence techniques. The activity of these compounds was estimated by means of combination of principal component analysis (PCA), as a well-known data reduction method, genetic algorithm (GA), as a variable selection technique, and artificial neural network (ANN), as a non-linear modeling method. First, a linear regression, combined with PCA, (principal component regression) was operated to model the structure-activity relationships, and afterwards a combination of PCA and ANN algorithm was employed to accurately predict the biological activity of the P2X7 antagonist. PCA preserves as much of the information as possible contained in the original data set. Seven most important PC's to the studied activity were selected as the inputs of ANN box by an efficient variable selection method, GA. The best computational neural network model was a fully-connected, feed-forward model with 7-7-1 architecture. The developed ANN model was fully evaluated by different validation techniques, including internal and external validation, and chemical applicability domain. All validations showed that the constructed quantitative structure-activity relationship model suggested is robust and satisfactory.

Quantitative structure–activity relationship study of P2X7 receptor inhibitors using combination of principal component analysis and artificial intelligence methods

PubMed Central

Ahmadi, Mehdi; Shahlaei, Mohsen

2015-01-01

P2X7 antagonist activity for a set of 49 molecules of the P2X7 receptor antagonists, derivatives of purine, was modeled with the aid of chemometric and artificial intelligence techniques. The activity of these compounds was estimated by means of combination of principal component analysis (PCA), as a well-known data reduction method, genetic algorithm (GA), as a variable selection technique, and artificial neural network (ANN), as a non-linear modeling method. First, a linear regression, combined with PCA, (principal component regression) was operated to model the structure–activity relationships, and afterwards a combination of PCA and ANN algorithm was employed to accurately predict the biological activity of the P2X7 antagonist. PCA preserves as much of the information as possible contained in the original data set. Seven most important PC's to the studied activity were selected as the inputs of ANN box by an efficient variable selection method, GA. The best computational neural network model was a fully-connected, feed-forward model with 7−7−1 architecture. The developed ANN model was fully evaluated by different validation techniques, including internal and external validation, and chemical applicability domain. All validations showed that the constructed quantitative structure–activity relationship model suggested is robust and satisfactory. PMID:26600858

Modeling of the relationship between dipeptide structure and dipeptide stability, permeability, and ACE inhibitory activity.

PubMed

Foltz, Martin; van Buren, Leo; Klaffke, Werner; Duchateau, Guus S M J E

2009-09-01

Selected di- and tripeptides exhibit angiotensin-I converting enzyme (ACE) inhibitory activity in vitro. However, the efficacy in vivo is most likely limited for most peptides due to low bioavailability. The purpose of this study was to identify descriptors of intestinal stability, permeability, and ACE inhibitory activity of dipeptides. A total of 228 dipeptides were synthesized; intestinal stability was obtained by in vitro digestion, intestinal permeability using Caco-2 cells and ACE inhibitory activity by an in vitro assay. Databases were constructed to study the relationship between structure and activity, permeability, and stability. Quantitative structure-activity relationship (QSAR) modeling was performed based on computed models using partial least squares regression based on 400 molecular descriptors. QSAR modeling of dipeptide stability revealed high correlation coefficients (R > 0.65) for models based on Z and X scales. However, amino acid (AA) clustering showed the best results in describing stability of dipeptides. The N-terminal AA residues Asp, Gly, and Pro as well as the C-terminal residues Pro, Ser, Thr, and Asp stabilize dipeptides toward luminal enzymatic peptide hydrolysis. QSAR modeling did not reveal significant correlation models for intestinal permeability. 2D-fingerprint models were identified describing ACE inhibitory activity of dipeptides. The intestinal stability of 12 peptides was predicted. Peptides were synthesized and stability was confirmed in simulated digestion experiments. Based on the results, specific dipeptides can be designed to meet both stability and activity criteria. However, postabsorptive ACE inhibitory activities of dipeptides in vivo are most likely limited due to the very low intestinal permeability of dipeptides.

The relationship of social support with treatment adherence and weight loss in Latinos with type 2 diabetes.

PubMed

Marquez, Becky; Anderson, Andrea; Wing, Rena R; West, Delia S; Newton, Robert L; Meacham, Maria; Hazuda, Helen P; Peters, Anne; Montez, Maria G; Broyles, Stephanie T; Walker, Martha; Evans-Hudsnall, Gina

2016-03-01

Little is known about the effects of social support on weight loss in Latinos. This study determined whether sex moderated and treatment adherence mediated the association between social support and weight loss. Data from 278 Latino males and females with type 2 diabetes in the Intensive Lifestyle Intervention of the Look AHEAD trial were analyzed. Multivariable modeling tested for moderation and parallel multiple mediator modeling simultaneously tested the mediating effects of adherence to physical activity, diet, and session attendance on the relationship between baseline social support and percent weight loss at 1 year. Social support for physical activity (having family and friends join in physical activity) was related to weight loss. Adherence to physical activity was related to both social support for physical activity and weight loss. Sex did not moderate these relationships. Adherence to physical activity completely mediated the relationship between social support for physical activity and weight loss. Increasing companionship for physical activity may be an effective intervention strategy to promote behaviors important for weight loss among Latinos. © 2016 The Obesity Society.

The relationship of social support with treatment adherence and weight loss in Latinos with type 2 diabetes

PubMed Central

Marquez, Becky; Anderson, Andrea; Wing, Rena R.; West, Delia S.; Newton, Robert L.; Meacham, Maria; Hazuda, Helen P.; Peters, Anne; Montez, Maria G.; Broyles, Stephanie T.; Walker, Martha; Evans-Hudsnall, Gina

2016-01-01

Objective Little is known about the effects of social support on weight loss in Latinos. This study determined whether sex moderated and treatment adherence mediated the association between social support and weight loss. Methods Data from 278 Latino males and females with type 2 diabetes in the Intensive Lifestyle Intervention of the Look AHEAD trial were analyzed. Multivariable modeling tested for moderation and parallel multiple mediator modeling simultaneously tested the mediating effects of adherence to physical activity, diet, and session attendance on the relationship between baseline social support and percent weight loss at 1 year. Results Social support for physical activity (having family and friends join in physical activity) was related to weight loss. Adherence to physical activity was related to both social support for physical activity and weight loss. Sex did not moderate these relationships. Adherence to physical activity completely mediated the relationship between social support for physical activity and weight loss. Conclusion Increasing companionship for physical activity may be an effective intervention strategy to promote behaviors important for weight loss among Latinos. PMID:26833676

Development and implementation of (Q)SAR modeling within the CHARMMing web-user interface.

PubMed

Weidlich, Iwona E; Pevzner, Yuri; Miller, Benjamin T; Filippov, Igor V; Woodcock, H Lee; Brooks, Bernard R

2015-01-05

Recent availability of large publicly accessible databases of chemical compounds and their biological activities (PubChem, ChEMBL) has inspired us to develop a web-based tool for structure activity relationship and quantitative structure activity relationship modeling to add to the services provided by CHARMMing (www.charmming.org). This new module implements some of the most recent advances in modern machine learning algorithms-Random Forest, Support Vector Machine, Stochastic Gradient Descent, Gradient Tree Boosting, so forth. A user can import training data from Pubchem Bioassay data collections directly from our interface or upload his or her own SD files which contain structures and activity information to create new models (either categorical or numerical). A user can then track the model generation process and run models on new data to predict activity. © 2014 Wiley Periodicals, Inc.

The Relationship between Particulate Pollution Levels in Australian Cities, Meteorology, and Landscape Fire Activity Detected from MODIS Hotspots

PubMed Central

Price, Owen F.; Williamson, Grant J.; Henderson, Sarah B.; Johnston, Fay; Bowman, David M. J. S.

2012-01-01

Smoke from bushfires is an emerging issue for fire managers because of increasing evidence for its public health effects. Development of forecasting models to predict future pollution levels based on the relationship between bushfire activity and current pollution levels would be a useful management tool. As a first step, we use daily thermal anomalies detected by the MODIS Active Fire Product (referred to as “hotspots”), pollution concentrations, and meteorological data for the years 2002 to 2008, to examine the statistical relationship between fire activity in the landscapes and pollution levels around Perth and Sydney, two large Australian cities. Resultant models were statistically significant, but differed in their goodness of fit and the distance at which the strength of the relationship was strongest. For Sydney, a univariate model for hotspot activity within 100 km explained 24% of variation in pollution levels, and the best model including atmospheric variables explained 56% of variation. For Perth, the best radius was 400 km, explaining only 7% of variation, while the model including atmospheric variables explained 31% of the variation. Pollution was higher when the atmosphere was more stable and in the presence of on-shore winds, whereas there was no effect of wind blowing from the fires toward the pollution monitors. Our analysis shows there is a good prospect for developing region-specific forecasting tools combining hotspot fire activity with meteorological data. PMID:23071788

Potential mediating pathways through which sports participation relates to reduced risk of suicidal ideation.

PubMed

Taliaferro, Lindsay A; Rienzo, Barbara A; Miller, M David; Pigg, R Morgan; Dodd, Virginia J

2010-09-01

Suicide ranks as the third leading cause of death for American youth. Researchers examining sport participation and suicidal behavior have regularly found inverse relationships. This study represents the first effort to test a model depicting potential mechanisms through which sport participation relates to reduced risk of suicidal ideation. The participants were 450 undergraduate students. Measures assessed participants' involvement in university-run sports and other activities; frequency of physical activity; and perceived social support, self-esteem, depression, hopelessness, loneliness, and suicidal ideation. Regression analyses confirmed a path model and tested for mediation effects. Vigorous activity mediated relationships between sport participation and self-esteem and depression; and self-esteem and depression mediated the relationship between vigorous activity and suicidal ideation. Social support mediated relationships between sport participation and depression, hopelessness, and loneliness; and each of these risk factors partially mediated the relationship between social support and suicidal ideation. However no variable fully mediated the relationship between sport participation and suicidal ideation. This study provides a foundation for research designed to examine pathways through which sport participation relates to reduced risk of suicidal behavior.

Developing sensor activity relationships for the JPL electronic nose sensors using molecular modeling and QSAR techniques

NASA Technical Reports Server (NTRS)

Shevade, A. V.; Ryan, M. A.; Homer, M. L.; Jewell, A. D.; Zhou, H.; Manatt, K.; Kisor, A. K.

2005-01-01

We report a Quantitative Structure-Activity Relationships (QSAR) study using Genetic Function Approximations (GFA) to describe the polymer-carbon composite sensor activities in the JPL Electronic Nose, when exposed to chemical vapors at parts-per-million concentration levels.

TOWARDS REFINED USE OF TOXICITY DATA IN ...

EPA Pesticide Factsheets

In 2003, an International Life Sciences Institute (ILSI) Working Group examined the potential of statistically based structure-activity relationship (SAR) models for use in screening environmental contaminants for possible developmental toxicants. In 2003, an International Life Sciences Institute (ILSI) Working Group examined the potential of statistically based structure-activity relationship (SAR) models for use in screening environmental contaminants for possible developmental toxicants.

Toll-like receptor 4-related immunostimulatory polysaccharides: Primary structure, activity relationships, and possible interaction models.

PubMed

Zhang, Xiaorui; Qi, Chunhui; Guo, Yan; Zhou, Wenxia; Zhang, Yongxiang

2016-09-20

Toll-like receptor (TLR) 4 is an important polysaccharide receptor; however, the relationships between the structures and biological activities of TLR4 and polysaccharides remain unknown. Many recent findings have revealed the primary structure of TLR4/MD-2-related polysaccharides, and several three-dimensional structure models of polysaccharide-binding proteins have been reported; and these models provide insights into the mechanisms through which polysaccharides interact with TLR4. In this review, we first discuss the origins of polysaccharides related to TLR4, including polysaccharides from higher plants, fungi, bacteria, algae, and animals. We then briefly describe the glucosidic bond types of TLR4-related heteroglycans and homoglycans and describe the typical molecular weights of TLR4-related polysaccharides. The primary structures and activity relationships of polysaccharides with TLR4/MD-2 are also discussed. Finally, based on the existing interaction models of LPS with TLR4/MD-2 and linear polysaccharides with proteins, we provide insights into the possible interaction models of polysaccharide ligands with TLR4/MD-2. To our knowledge, this review is the first to summarize the primary structures and activity relationships of TLR4-related polysaccharides and the possible mechanisms of interaction for TLR4 and TLR4-related polysaccharides. Copyright © 2016 Elsevier Ltd. All rights reserved.

The role of companionship, esteem, and informational support in explaining physical activity among young women in an online social network intervention.

PubMed

Cavallo, David N; Brown, Jane D; Tate, Deborah F; DeVellis, Robert F; Zimmer, Catherine; Ammerman, Alice S

2014-10-01

The primary objective of the current study was to examine the relationship between social support and physical activity within the theory of planned behavior (TPB) theoretical framework. This study used data from the Internet Support for Healthy Associations Promoting Exercise randomized controlled trial. A total of 134 female undergraduate students participated in the study, which included baseline and post measures of perceived social support for physical activity (esteem, informational, and companionship), TPB variables related to physical activity (perceived behavioral control, intention, and attitude), and physical activity behavior. Path analysis revealed a significant indirect relationship between change in companionship support and physical activity mediated by change in intention (.13, p < .01) and a significant direct relationship between change in esteem support and change in physical activity (.26, p = .03). The model explained 27% of the variance in physical activity and 59% of the variance in intention. Overall, change in social support exerted a small to medium amount of influence on change in physical activity in this modified TPB model when controlling for traditional model constructs. Encouraging companionship and esteem support should be considered as a strategy for increasing physical activity in this population.

Weather and children's physical activity; how and why do relationships vary between countries?

PubMed

Harrison, Flo; Goodman, Anna; van Sluijs, Esther M F; Andersen, Lars Bo; Cardon, Greet; Davey, Rachel; Janz, Kathleen F; Kriemler, Susi; Molloy, Lynn; Page, Angie S; Pate, Russ; Puder, Jardena J; Sardinha, Luis B; Timperio, Anna; Wedderkopp, Niels; Jones, Andy P

2017-05-30

Globally most children do not engage in enough physical activity. Day length and weather conditions have been identified as determinants of physical activity, although how they may be overcome as barriers is not clear. We aim to examine if and how relationships between children's physical activity and weather and day length vary between countries and identify settings in which children were better able to maintain activity levels given the weather conditions they experienced. In this repeated measures study, we used data from 23,451 participants in the International Children's Accelerometry Database (ICAD). Daily accelerometer-measured physical activity (counts per minute; cpm) was matched to local weather conditions and the relationships assessed using multilevel regression models. Multilevel models accounted for clustering of days within occasions within children within study-cities, and allowed us to explore if and how the relationships between weather variables and physical activity differ by setting. Increased precipitation and wind speed were associated with decreased cpm while better visibility and more hours of daylight were associated with increased cpm. Models indicated that increases in these variables resulted in average changes in mean cpm of 7.6/h of day length, -13.2/cm precipitation, 10.3/10 km visibility and -10.3/10kph wind speed (all p < 0.01). Temperature showed a cubic relationship with cpm, although between 0 and 20 degrees C the relationship was broadly linear. Age showed interactions with temperature and precipitation, with the associations larger among younger children. In terms of geographic trends, participants from Northern European countries and Melbourne, Australia were the most active, and also better maintained their activity levels given the weather conditions they experienced compared to those in the US and Western Europe. We found variation in the relationship between weather conditions and physical activity between ICAD studies and settings. Children in Northern Europe and Melbourne, Australia were not only more active on average, but also more active given the weather conditions they experienced. Future work should consider strategies to mitigate the impacts of weather conditions, especially among young children, and interventions involving changes to the physical environment should consider how they will operate in different weather conditions.

The role of Patient Health Engagement Model (PHE-model) in affecting patient activation and medication adherence: A structural equation model

PubMed Central

Graffigna, Guendalina; Bonanomi, Andrea

2017-01-01

Background Increasing bodies of scientific research today examines the factors and interventions affecting patients’ ability to self-manage and adhere to treatment. Patient activation is considered the most reliable indicator of patients’ ability to manage health autonomously. Only a few studies have tried to assess the role of psychosocial factors in promoting patient activation. A more systematic modeling of the psychosocial factors explaining the variance of patient activation is needed. Objective To test the hypothesized effect of patient activation on medication adherence; to test the the hypothesized effects of positive emotions and of the quality of the patient/doctor relationship on patient activation; and to test the hypothesized mediating effect of Patient Health Engagement (PHE-model) in this pathway. Material and methods This cross-sectional study involved 352 Italian-speaking adult chronic patients. The survey included measures of i) patient activation (Patient Activation Measure 13 –short form); ii) Patient Health Engagement model (Patient Health Engagement Scale); iii) patient adherence (4 item-Morinsky Medication Adherence Scale); iv) the quality of the patients’ emotional feelings (Manikin Self Assessment Scale); v) the quality of the patient/doctor relationship (Health Care Climate Questionnaire). Structural equation modeling was used to test the hypotheses proposed. Results According to the theoretical model we hypothesized, research results confirmed that patients’ activation significantly affects their reported medication adherence. Moreover, psychosocial factors, such as the patients’ quality of the emotional feelings and the quality of the patient/doctor relationship were demonstrated to be factors affecting the level of patient activation. Finally, the mediation effect of the Patient Health Engagement model was confirmed by the analysis. Conclusions Consistently with the results of previous studies, these findings demonstrate that the Patient Health Engagement Model is a critical factor in enhancing the quality of care. The Patient Health Engagement Model might acts as a mechanism to increase patient activation and adherence. PMID:28654686

The role of Patient Health Engagement Model (PHE-model) in affecting patient activation and medication adherence: A structural equation model.

PubMed

Graffigna, Guendalina; Barello, Serena; Bonanomi, Andrea

2017-01-01

Increasing bodies of scientific research today examines the factors and interventions affecting patients' ability to self-manage and adhere to treatment. Patient activation is considered the most reliable indicator of patients' ability to manage health autonomously. Only a few studies have tried to assess the role of psychosocial factors in promoting patient activation. A more systematic modeling of the psychosocial factors explaining the variance of patient activation is needed. To test the hypothesized effect of patient activation on medication adherence; to test the the hypothesized effects of positive emotions and of the quality of the patient/doctor relationship on patient activation; and to test the hypothesized mediating effect of Patient Health Engagement (PHE-model) in this pathway. This cross-sectional study involved 352 Italian-speaking adult chronic patients. The survey included measures of i) patient activation (Patient Activation Measure 13 -short form); ii) Patient Health Engagement model (Patient Health Engagement Scale); iii) patient adherence (4 item-Morinsky Medication Adherence Scale); iv) the quality of the patients' emotional feelings (Manikin Self Assessment Scale); v) the quality of the patient/doctor relationship (Health Care Climate Questionnaire). Structural equation modeling was used to test the hypotheses proposed. According to the theoretical model we hypothesized, research results confirmed that patients' activation significantly affects their reported medication adherence. Moreover, psychosocial factors, such as the patients' quality of the emotional feelings and the quality of the patient/doctor relationship were demonstrated to be factors affecting the level of patient activation. Finally, the mediation effect of the Patient Health Engagement model was confirmed by the analysis. Consistently with the results of previous studies, these findings demonstrate that the Patient Health Engagement Model is a critical factor in enhancing the quality of care. The Patient Health Engagement Model might acts as a mechanism to increase patient activation and adherence.

Analysis of stress-strain relationships in silicon ribbon

NASA Technical Reports Server (NTRS)

Dillon, O. W., Jr.

1984-01-01

An analysis of stress-strain relationships in silicon ribbon is presented. A model to present entire process, dynamical Transit Analysis is developed. It is found that knowledge of past-strain history is significant in modeling activities.

Structure-activity relationships between sterols and their thermal stability in oil matrix.

PubMed

Hu, Yinzhou; Xu, Junli; Huang, Weisu; Zhao, Yajing; Li, Maiquan; Wang, Mengmeng; Zheng, Lufei; Lu, Baiyi

2018-08-30

Structure-activity relationships between 20 sterols and their thermal stabilities were studied in a model oil system. All sterol degradations were found to be consistent with a first-order kinetic model with determination of coefficient (R 2 ) higher than 0.9444. The number of double bonds in the sterol structure was negatively correlated with the thermal stability of sterol, whereas the length of the branch chain was positively correlated with the thermal stability of sterol. A quantitative structure-activity relationship (QSAR) model to predict thermal stability of sterol was developed by using partial least squares regression (PLSR) combined with genetic algorithm (GA). A regression model was built with R 2 of 0.806. Almost all sterol degradation constants can be predicted accurately with R 2 of cross-validation equals to 0.680. Four important variables were selected in optimal QSAR model and the selected variables were observed to be related with information indices, RDF descriptors, and 3D-MoRSE descriptors. Copyright © 2018 Elsevier Ltd. All rights reserved.

Quantitative structure-activity relationship (QSAR) for insecticides: development of predictive in vivo insecticide activity models.

PubMed

Naik, P K; Singh, T; Singh, H

2009-07-01

Quantitative structure-activity relationship (QSAR) analyses were performed independently on data sets belonging to two groups of insecticides, namely the organophosphates and carbamates. Several types of descriptors including topological, spatial, thermodynamic, information content, lead likeness and E-state indices were used to derive quantitative relationships between insecticide activities and structural properties of chemicals. A systematic search approach based on missing value, zero value, simple correlation and multi-collinearity tests as well as the use of a genetic algorithm allowed the optimal selection of the descriptors used to generate the models. The QSAR models developed for both organophosphate and carbamate groups revealed good predictability with r(2) values of 0.949 and 0.838 as well as [image omitted] values of 0.890 and 0.765, respectively. In addition, a linear correlation was observed between the predicted and experimental LD(50) values for the test set data with r(2) of 0.871 and 0.788 for both the organophosphate and carbamate groups, indicating that the prediction accuracy of the QSAR models was acceptable. The models were also tested successfully from external validation criteria. QSAR models developed in this study should help further design of novel potent insecticides.

Comparison of 3D quantitative structure-activity relationship methods: Analysis of the in vitro antimalarial activity of 154 artemisinin analogues by hypothetical active-site lattice and comparative molecular field analysis

NASA Astrophysics Data System (ADS)

Woolfrey, John R.; Avery, Mitchell A.; Doweyko, Arthur M.

1998-03-01

Two three-dimensional quantitative structure-activity relationship (3D-QSAR) methods, comparative molecular field analysis (CoMFA) and hypothetical active site lattice (HASL), were compared with respect to the analysis of a training set of 154 artemisinin analogues. Five models were created, including a complete HASL and two trimmed versions, as well as two CoMFA models (leave-one-out standard CoMFA and the guided-region selection protocol). Similar r2 and q2 values were obtained by each method, although some striking differences existed between CoMFA contour maps and the HASL output. Each of the four predictive models exhibited a similar ability to predict the activity of a test set of 23 artemisinin analogues, although some differences were noted as to which compounds were described well by either model.

The changing strength and nature of fire-climate relationships in the northern Rocky Mountains, U.S.A., 1902-2008

USGS Publications Warehouse

Littell, Jeremy

2015-01-01

Time-varying fire-climate relationships may represent an important component of fire-regime variability, relevant for understanding the controls of fire and projecting fire activity under global-change scenarios. We used time-varying statistical models to evaluate if and how fire-climate relationships varied from 1902-2008, in one of the most flammable forested regions of the western U.S.A. Fire-danger and water-balance metrics yielded the best combination of calibration accuracy and predictive skill in modeling annual area burned. The strength of fire-climate relationships varied markedly at multi-decadal scales, with models explaining < 40% to 88% of the variation in annual area burned. The early 20th century (1902-1942) and the most recent two decades (1985-2008) exhibited strong fire-climate relationships, with weaker relationships for much of the mid 20th century (1943-1984), coincident with diminished burning, less fire-conducive climate, and the initiation of modern fire fighting. Area burned and the strength of fire-climate relationships increased sharply in the mid 1980s, associated with increased temperatures and longer potential fire seasons. Unlike decades with high burning in the early 20th century, models developed using fire-climate relationships from recent decades overpredicted area burned when applied to earlier periods. This amplified response of fire to climate is a signature of altered fire-climate-relationships, and it implicates non-climatic factors in this recent shift. Changes in fuel structure and availability following 40+ yr of unusually low fire activity, and possibly land use, may have resulted in increased fire vulnerability beyond expectations from climatic factors alone. Our results highlight the potential for non-climatic factors to alter fire-climate relationships, and the need to account for such dynamics, through adaptable statistical or processes-based models, for accurately predicting future fire activity.

The Changing Strength and Nature of Fire-Climate Relationships in the Northern Rocky Mountains, U.S.A., 1902-2008

PubMed Central

Higuera, Philip E.; Abatzoglou, John T.; Littell, Jeremy S.; Morgan, Penelope

2015-01-01

Time-varying fire-climate relationships may represent an important component of fire-regime variability, relevant for understanding the controls of fire and projecting fire activity under global-change scenarios. We used time-varying statistical models to evaluate if and how fire-climate relationships varied from 1902-2008, in one of the most flammable forested regions of the western U.S.A. Fire-danger and water-balance metrics yielded the best combination of calibration accuracy and predictive skill in modeling annual area burned. The strength of fire-climate relationships varied markedly at multi-decadal scales, with models explaining < 40% to 88% of the variation in annual area burned. The early 20th century (1902-1942) and the most recent two decades (1985-2008) exhibited strong fire-climate relationships, with weaker relationships for much of the mid 20th century (1943-1984), coincident with diminished burning, less fire-conducive climate, and the initiation of modern fire fighting. Area burned and the strength of fire-climate relationships increased sharply in the mid 1980s, associated with increased temperatures and longer potential fire seasons. Unlike decades with high burning in the early 20th century, models developed using fire-climate relationships from recent decades overpredicted area burned when applied to earlier periods. This amplified response of fire to climate is a signature of altered fire-climate-relationships, and it implicates non-climatic factors in this recent shift. Changes in fuel structure and availability following 40+ yr of unusually low fire activity, and possibly land use, may have resulted in increased fire vulnerability beyond expectations from climatic factors alone. Our results highlight the potential for non-climatic factors to alter fire-climate relationships, and the need to account for such dynamics, through adaptable statistical or processes-based models, for accurately predicting future fire activity. PMID:26114580

The Changing Strength and Nature of Fire-Climate Relationships in the Northern Rocky Mountains, U.S.A., 1902-2008.

PubMed

Higuera, Philip E; Abatzoglou, John T; Littell, Jeremy S; Morgan, Penelope

2015-01-01

Time-varying fire-climate relationships may represent an important component of fire-regime variability, relevant for understanding the controls of fire and projecting fire activity under global-change scenarios. We used time-varying statistical models to evaluate if and how fire-climate relationships varied from 1902-2008, in one of the most flammable forested regions of the western U.S.A. Fire-danger and water-balance metrics yielded the best combination of calibration accuracy and predictive skill in modeling annual area burned. The strength of fire-climate relationships varied markedly at multi-decadal scales, with models explaining < 40% to 88% of the variation in annual area burned. The early 20th century (1902-1942) and the most recent two decades (1985-2008) exhibited strong fire-climate relationships, with weaker relationships for much of the mid 20th century (1943-1984), coincident with diminished burning, less fire-conducive climate, and the initiation of modern fire fighting. Area burned and the strength of fire-climate relationships increased sharply in the mid 1980s, associated with increased temperatures and longer potential fire seasons. Unlike decades with high burning in the early 20th century, models developed using fire-climate relationships from recent decades overpredicted area burned when applied to earlier periods. This amplified response of fire to climate is a signature of altered fire-climate-relationships, and it implicates non-climatic factors in this recent shift. Changes in fuel structure and availability following 40+ yr of unusually low fire activity, and possibly land use, may have resulted in increased fire vulnerability beyond expectations from climatic factors alone. Our results highlight the potential for non-climatic factors to alter fire-climate relationships, and the need to account for such dynamics, through adaptable statistical or processes-based models, for accurately predicting future fire activity.

ESTIMATION OF CHEMICAL SPECIFIC PARAMETERS WITHIN PHYSIOLOGICALLY BASED PHARMACOKINETIC/PHARMACODYNAMIC MODELS

EPA Science Inventory

While relationships between chemical structure and observed properties or activities (QSAR - quantitative structure activity relationship) can be used to predict the behavior of unknown chemicals, this method is semiempirical in nature relying on high quality experimental data to...

Mechanistic insights into heterogeneous methane activation

DOE PAGES

Latimer, Allegra A.; Aljama, Hassan; Kakekhani, Arvin; ...

2017-01-11

While natural gas is an abundant chemical fuel, its low volumetric energy density has prompted a search for catalysts able to transform methane into more useful chemicals. This search has often been aided through the use of transition state (TS) scaling relationships, which estimate methane activation TS energies as a linear function of a more easily calculated descriptor, such as final state energy, thus avoiding tedious TS energy calculations. It has been shown that methane can be activated via a radical or surface-stabilized pathway, both of which possess a unique TS scaling relationship. Herein, we present a simple model tomore » aid in the prediction of methane activation barriers on heterogeneous catalysts. Analogous to the universal radical TS scaling relationship introduced in a previous publication, we show that a universal TS scaling relationship that transcends catalysts classes also seems to exist for surface-stabilized methane activation if the relevant final state energy is used. We demonstrate that this scaling relationship holds for several reducible and irreducible oxides, promoted metals, and sulfides. By combining the universal scaling relationships for both radical and surface-stabilized methane activation pathways, we show that catalyst reactivity must be considered in addition to catalyst geometry to obtain an accurate estimation for the TS energy. Here, this model can yield fast and accurate predictions of methane activation barriers on a wide range of catalysts, thus accelerating the discovery of more active catalysts for methane conversion.« less

Mechanistic insights into heterogeneous methane activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latimer, Allegra A.; Aljama, Hassan; Kakekhani, Arvin

While natural gas is an abundant chemical fuel, its low volumetric energy density has prompted a search for catalysts able to transform methane into more useful chemicals. This search has often been aided through the use of transition state (TS) scaling relationships, which estimate methane activation TS energies as a linear function of a more easily calculated descriptor, such as final state energy, thus avoiding tedious TS energy calculations. It has been shown that methane can be activated via a radical or surface-stabilized pathway, both of which possess a unique TS scaling relationship. Herein, we present a simple model tomore » aid in the prediction of methane activation barriers on heterogeneous catalysts. Analogous to the universal radical TS scaling relationship introduced in a previous publication, we show that a universal TS scaling relationship that transcends catalysts classes also seems to exist for surface-stabilized methane activation if the relevant final state energy is used. We demonstrate that this scaling relationship holds for several reducible and irreducible oxides, promoted metals, and sulfides. By combining the universal scaling relationships for both radical and surface-stabilized methane activation pathways, we show that catalyst reactivity must be considered in addition to catalyst geometry to obtain an accurate estimation for the TS energy. Here, this model can yield fast and accurate predictions of methane activation barriers on a wide range of catalysts, thus accelerating the discovery of more active catalysts for methane conversion.« less

The effect of leverage and/or influential on structure-activity relationships.

PubMed

Bolboacă, Sorana D; Jäntschi, Lorentz

2013-05-01

In the spirit of reporting valid and reliable Quantitative Structure-Activity Relationship (QSAR) models, the aim of our research was to assess how the leverage (analysis with Hat matrix, h(i)) and the influential (analysis with Cook's distance, D(i)) of QSAR models may reflect the models reliability and their characteristics. The datasets included in this research were collected from previously published papers. Seven datasets which accomplished the imposed inclusion criteria were analyzed. Three models were obtained for each dataset (full-model, h(i)-model and D(i)-model) and several statistical validation criteria were applied to the models. In 5 out of 7 sets the correlation coefficient increased when compounds with either h(i) or D(i) higher than the threshold were removed. Withdrawn compounds varied from 2 to 4 for h(i)-models and from 1 to 13 for D(i)-models. Validation statistics showed that D(i)-models possess systematically better agreement than both full-models and h(i)-models. Removal of influential compounds from training set significantly improves the model and is recommended to be conducted in the process of quantitative structure-activity relationships developing. Cook's distance approach should be combined with hat matrix analysis in order to identify the compounds candidates for removal.

Modelling the maximum voluntary joint torque/angular velocity relationship in human movement.

PubMed

Yeadon, Maurice R; King, Mark A; Wilson, Cassie

2006-01-01

The force exerted by a muscle is a function of the activation level and the maximum (tetanic) muscle force. In "maximum" voluntary knee extensions muscle activation is lower for eccentric muscle velocities than for concentric velocities. The aim of this study was to model this "differential activation" in order to calculate the maximum voluntary knee extensor torque as a function of knee angular velocity. Torque data were collected on two subjects during maximal eccentric-concentric knee extensions using an isovelocity dynamometer with crank angular velocities ranging from 50 to 450 degrees s(-1). The theoretical tetanic torque/angular velocity relationship was modelled using a four parameter function comprising two rectangular hyperbolas while the activation/angular velocity relationship was modelled using a three parameter function that rose from submaximal activation for eccentric velocities to full activation for high concentric velocities. The product of these two functions gave a seven parameter function which was fitted to the joint torque/angular velocity data, giving unbiased root mean square differences of 1.9% and 3.3% of the maximum torques achieved. Differential activation accounts for the non-hyperbolic behaviour of the torque/angular velocity data for low concentric velocities. The maximum voluntary knee extensor torque that can be exerted may be modelled accurately as the product of functions defining the maximum torque and the maximum voluntary activation level. Failure to include differential activation considerations when modelling maximal movements will lead to errors in the estimation of joint torque in the eccentric phase and low velocity concentric phase.

A prospective examination of the relationship between physical activity and dementia risk in later life.

PubMed

Bowen, Mary Elizabeth

2012-01-01

To examine the relationship between vigorous physical activity and dementia risk. Prospective study design utilizing physical activity data from the Health and Retirement Study and cognitive outcome data from the Aging, Demographics, and Memory Study. Community-based. Adults age 71 and over (N  =  808) with 3 to 7 years of physical activity information prior to dementia/no dementia diagnosis. Physical activity was measured by participation in vigorous activities such as aerobics, sports, running, bicycling, and heavy housework three or more times per week (yes/no). Dementia diagnosis was based on an expert panel (e.g., neuropsychologists, neurologists, geropsychiatrists) who performed and reviewed a battery of neuropsychological tests. Binary logistic regression models were used to account for demographic characteristics, genetic risk factors (one or two apolipoprotein E ε4 alleles), health behaviors (e.g., smoking, drinking alcohol), health indicators (body mass index), and health conditions (e.g., diabetes, heart disease) in a sequential model-building process. The relationship between vigorous physical activity and dementia risk remained robust across models. In the final model, older adults who were physically active were 21% (p ≤ .05) less likely than their counterparts to be diagnosed with dementia. Vigorous physical activity may reduce the risk for dementia independently of the factors examined here. This study's findings are important given that few preventative strategies for dementia have been explored beyond hormonal therapy and anti-inflammatory drugs.

Promoting Teachers' Implementation of Classroom-Based Prevention Programming Through Coaching: The Mediating Role of the Coach-Teacher Relationship.

PubMed

Johnson, Stacy R; Pas, Elise T; Bradshaw, Catherine P; Ialongo, Nicholas S

2018-05-01

There is growing awareness of the importance of implementation fidelity and the supports, such as coaching, to optimize it. This study examined how coaching activities (i.e., check-ins, needs assessment, modeling, and technical assistance) related directly and indirectly to implementation dosage and quality of the PAX Good Behavior Game, via a mediating pathway through working relationship. Mediation analyses of 138 teachers revealed direct effects of modeling and working relationship on implementation dosage, whereas needs assessment was associated with greater dosage indirectly, by higher ratings of the working relationship. Understanding how coaching activities promote implementation fidelity elements has implications for improving program effectiveness.

Quantitative structure activity relationship (QSAR) of piperine analogs for bacterial NorA efflux pump inhibitors.

PubMed

Nargotra, Amit; Sharma, Sujata; Koul, Jawahir Lal; Sangwan, Pyare Lal; Khan, Inshad Ali; Kumar, Ashwani; Taneja, Subhash Chander; Koul, Surrinder

2009-10-01

Quantitative structure activity relationship (QSAR) analysis of piperine analogs as inhibitors of efflux pump NorA from Staphylococcus aureus has been performed in order to obtain a highly accurate model enabling prediction of inhibition of S. aureus NorA of new chemical entities from natural sources as well as synthetic ones. Algorithm based on genetic function approximation method of variable selection in Cerius2 was used to generate the model. Among several types of descriptors viz., topological, spatial, thermodynamic, information content and E-state indices that were considered in generating the QSAR model, three descriptors such as partial negative surface area of the compounds, area of the molecular shadow in the XZ plane and heat of formation of the molecules resulted in a statistically significant model with r(2)=0.962 and cross-validation parameter q(2)=0.917. The validation of the QSAR models was done by cross-validation, leave-25%-out and external test set prediction. The theoretical approach indicates that the increase in the exposed partial negative surface area increases the inhibitory activity of the compound against NorA whereas the area of the molecular shadow in the XZ plane is inversely proportional to the inhibitory activity. This model also explains the relationship of the heat of formation of the compound with the inhibitory activity. The model is not only able to predict the activity of new compounds but also explains the important regions in the molecules in quantitative manner.

The Relationship Between Approach to Activity Engagement, Specific Aspects of Physical Function, and Pain Duration in Chronic Pain.

PubMed

Andrews, Nicole E; Strong, Jenny; Meredith, Pamela J

2016-01-01

To examine: (1) the relationships between habitual approach to activity engagement and specific aspects of physical functioning in chronic pain; and (2) whether or not these relationships differ according to pain duration. Outpatients (N=169) with generalized chronic pain completed a set of written questionnaires. Categories of "approach to activity engagement" were created using the confronting and avoidance subscales of the Pain and Activity Relations Questionnaire. An interaction term between "approach to activity engagement" categories and pain duration was entered into analysis with age, sex, pain intensity, the categorical "approach to activity engagement" variable, and pain duration, in 9 ordinal regression models investigating functioning in a variety of daily activities. The "approach to activity engagement" category predicted the personal care, lifting, sleeping, social life, and traveling aspects of physical functioning but, interestingly, not the performance skills used during these activities, that is, walking, sitting, and standing. The interaction term was significant in 2 models; however, the effect of pain duration on associations was the inverse of that theorized, with the relationship between variables becoming less pronounced with increasing duration of pain. The results of this study do not support the commonly held notion that avoidance and/or overactivity behavior leads to deconditioning and reduced physical capacity over time. Findings do, however, suggest that a relationship exists between avoidance and/or overactivity behavior and reduced participation in activities. Implications for the clinical management of chronic pain and directions for further research are discussed.

Longitudinal Relationships Between Productive Activities and Functional Health in Later Years: A Multivariate Latent Growth Curve Modeling Approach.

PubMed

Choi, Eunhee; Tang, Fengyan; Kim, Sung-Geun; Turk, Phillip

2016-10-01

This study examined the longitudinal relationships between functional health in later years and three types of productive activities: volunteering, full-time, and part-time work. Using the data from five waves (2000-2008) of the Health and Retirement Study, we applied multivariate latent growth curve modeling to examine the longitudinal relationships among individuals 50 or over. Functional health was measured by limitations in activities of daily living. Individuals who volunteered, worked either full time or part time exhibited a slower decline in functional health than nonparticipants. Significant associations were also found between initial functional health and longitudinal changes in productive activity participation. This study provides additional support for the benefits of productive activities later in life; engagement in volunteering and employment are indeed associated with better functional health in middle and old age. © The Author(s) 2016.

Quantitative structure-antifungal activity relationships of some benzohydrazides against Botrytis cinerea.

PubMed

Reino, José L; Saiz-Urra, Liane; Hernandez-Galan, Rosario; Aran, Vicente J; Hitchcock, Peter B; Hanson, James R; Gonzalez, Maykel Perez; Collado, Isidro G

2007-06-27

Fourteen benzohydrazides have been synthesized and evaluated for their in vitro antifungal activity against the phytopathogenic fungus Botrytis cinerea. The best antifungal activity was observed for the N',N'-dibenzylbenzohydrazides 3b-d and for the N-aminoisoindoline-derived benzohydrazide 5. A quantitative structure-activity relationship (QSAR) study has been developed using a topological substructural molecular design (TOPS-MODE) approach to interpret the antifungal activity of these synthetic compounds. The model described 98.3% of the experimental variance, with a standard deviation of 4.02. The influence of an ortho substituent on the conformation of the benzohydrazides was investigated by X-ray crystallography and supported by QSAR study. Several aspects of the structure-activity relationships are discussed in terms of the contribution of different bonds to the antifungal activity, thereby making the relationships between structure and biological activity more transparent.

Quantitative structure-activation barrier relationship modeling for Diels-Alder ligations utilizing quantum chemical structural descriptors.

PubMed

Nandi, Sisir; Monesi, Alessandro; Drgan, Viktor; Merzel, Franci; Novič, Marjana

2013-10-30

In the present study, we show the correlation of quantum chemical structural descriptors with the activation barriers of the Diels-Alder ligations. A set of 72 non-catalysed Diels-Alder reactions were subjected to quantitative structure-activation barrier relationship (QSABR) under the framework of theoretical quantum chemical descriptors calculated solely from the structures of diene and dienophile reactants. Experimental activation barrier data were obtained from literature. Descriptors were computed using Hartree-Fock theory using 6-31G(d) basis set as implemented in Gaussian 09 software. Variable selection and model development were carried out by stepwise multiple linear regression methodology. Predictive performance of the quantitative structure-activation barrier relationship (QSABR) model was assessed by training and test set concept and by calculating leave-one-out cross-validated Q2 and predictive R2 values. The QSABR model can explain and predict 86.5% and 80% of the variances, respectively, in the activation energy barrier training data. Alternatively, a neural network model based on back propagation of errors was developed to assess the nonlinearity of the sought correlations between theoretical descriptors and experimental reaction barriers. A reasonable predictability for the activation barrier of the test set reactions was obtained, which enabled an exploration and interpretation of the significant variables responsible for Diels-Alder interaction between dienes and dienophiles. Thus, studies in the direction of QSABR modelling that provide efficient and fast prediction of activation barriers of the Diels-Alder reactions turn out to be a meaningful alternative to transition state theory based computation.

The relationship between RMS electromyography and thickness change in the skeletal muscles.

PubMed

Kian-Bostanabad, Sharareh; Azghani, Mahmood-Reza

2017-05-01

The knowledge of muscle function may affect prescribing medications and physical treatments. Recently, ultrasound and electromyography (EMG) have been used to assess the skeletal muscles activity. The relationship between these methods has been reported in numerous articles qualitatively. In this paper, the relationship between EMG root-mean-square (RMS) and ultrasound data of muscle thickness has been investigated using Response Surface Methodology in the muscles separately and together and predictive models reported. Results show that to assess the relationship between the changes of thickness and activity (EMG) in muscles, we can use quadratic model for the rectus femoris, tibialis anterior, transverse abdominal, biceps brachii and brachialis muscles (R 2 =0.624-0.891) and linear model for the internal and external oblique abdominal, lumbar multifidus and deep cervical flexor muscles (R 2 =0.348-0.767). Due to the high correlation coefficient for the equations in the bulky muscles, it seems that the correlation between EMG RMS and ultrasound data of muscle thickness on the bulky muscles is higher than the flat muscles. This relationship may depend more on the type of activity than the type of muscle. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Physical activity, self-efficacy, and quality of life in older Czech adults.

PubMed

Mudrak, Jiri; Stochl, Jan; Slepicka, Pavel; Elavsky, Steriani

2016-03-01

Despite efforts to expand global physical activity (PA) surveillance data to include both low- and high-income countries worldwide, our understanding of the relationship between PA and quality of life (QOL) in older adults from culturally diverse backgrounds is limited. We tested McAuley's social-cognitive model of the PA-QOL relationship in the cultural context of the Czech Republic, a post-communist central European country. A total of 546 older Czech adults (mean age 68 years) completed a battery of questionnaires assessing indicators of PA, self-efficacy, health status, and global QOL. A structural equation model was used to test the relationship between PA and QOL. The model hypothesized an indirect relationship between PA and QOL: PA predicted self-efficacy, which in turn predicted global QOL through mental and physical health status. The analyses indicated an acceptable fit of the proposed model, albeit with different emphases than those of studies from Western countries. Above all, we observed a stronger effect of PA on self-efficacy and a weaker mediating effect of health status on the PA-QOL relationship. Our findings supported the validity of McAuley's PA-QOL social-cognitive model for a non-Western cultural context. However, it seems that self-efficacy and health status may influence the PA-QOL relationship in this population in a manner different from that proposed in McAuley's model.

QSAR Analysis of 2-Amino or 2-Methyl-1-Substituted Benzimidazoles Against Pseudomonas aeruginosa

PubMed Central

Podunavac-Kuzmanović, Sanja O.; Cvetković, Dragoljub D.; Barna, Dijana J.

2009-01-01

A set of benzimidazole derivatives were tested for their inhibitory activities against the Gram-negative bacterium Pseudomonas aeruginosa and minimum inhibitory concentrations were determined for all the compounds. Quantitative structure activity relationship (QSAR) analysis was applied to fourteen of the abovementioned derivatives using a combination of various physicochemical, steric, electronic, and structural molecular descriptors. A multiple linear regression (MLR) procedure was used to model the relationships between molecular descriptors and the antibacterial activity of the benzimidazole derivatives. The stepwise regression method was used to derive the most significant models as a calibration model for predicting the inhibitory activity of this class of molecules. The best QSAR models were further validated by a leave one out technique as well as by the calculation of statistical parameters for the established theoretical models. To confirm the predictive power of the models, an external set of molecules was used. High agreement between experimental and predicted inhibitory values, obtained in the validation procedure, indicated the good quality of the derived QSAR models. PMID:19468332

The morphology of flare phenomena, magnetic fields, and electric currents in active regions. I - Introduction and methods

NASA Technical Reports Server (NTRS)

Canfield, Richard C.; De La Beaujardiere, J.-F.; Fan, Yuhong; Leka, K. D.; Mcclymont, A. N.; Metcalf, Thomas R.; Mickey, Donald L.; Wuelser, Jean-Pierre; Lites, Bruce W.

1993-01-01

Electric current systems in solar active regions and their spatial relationship to sites of electron precipitation and high-pressure in flares were studied with the purpose of providing observational evidence for or against the flare models commonly discussed in the literature. The paper describes the instrumentation, the data used, and the data analysis methods, as well as improvements made upon earlier studies. Several flare models are overviewed, and the predictions yielded by each model for the relationships of flares to the vertical current systems are discussed.

Structure-Thermodynamics-Antioxidant Activity Relationships of Selected Natural Phenolic Acids and Derivatives: An Experimental and Theoretical Evaluation

PubMed Central

Zheng, Jie; Liang, Guizhao

2015-01-01

Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media. PMID:25803685

Structure-thermodynamics-antioxidant activity relationships of selected natural phenolic acids and derivatives: an experimental and theoretical evaluation.

PubMed

Chen, Yuzhen; Xiao, Huizhi; Zheng, Jie; Liang, Guizhao

2015-01-01

Phenolic acids and derivatives have potential biological functions, however, little is known about the structure-activity relationships and the underlying action mechanisms of these phenolic acids to date. Herein we investigate the structure-thermodynamics-antioxidant relationships of 20 natural phenolic acids and derivatives using DPPH• scavenging assay, density functional theory calculations at the B3LYP/6-311++G(d,p) levels of theory, and quantitative structure-activity relationship (QSAR) modeling. Three main working mechanisms (HAT, SETPT and SPLET) are explored in four micro-environments (gas-phase, benzene, water and ethanol). Computed thermodynamics parameters (BDE, IP, PDE, PA and ETE) are compared with the experimental radical scavenging activities against DPPH•. Available theoretical and experimental investigations have demonstrated that the extended delocalization and intra-molecular hydrogen bonds are the two main contributions to the stability of the radicals. The C = O or C = C in COOH, COOR, C = CCOOH and C = CCOOR groups, and orthodiphenolic functionalities are shown to favorably stabilize the specific radical species to enhance the radical scavenging activities, while the presence of the single OH in the ortho position of the COOH group disfavors the activities. HAT is the thermodynamically preferred mechanism in the gas phase and benzene, whereas SPLET in water and ethanol. Furthermore, our QSAR models robustly represent the structure-activity relationships of these explored compounds in polar media.

Quantitative structure-activity relationship of organosulphur compounds as soybean 15-lipoxygenase inhibitors using CoMFA and CoMSIA.

PubMed

Caballero, Julio; Fernández, Michael; Coll, Deysma

2010-12-01

Three-dimensional quantitative structure-activity relationship studies were carried out on a series of 28 organosulphur compounds as 15-lipoxygenase inhibitors using comparative molecular field analysis and comparative molecular similarity indices analysis. Quantitative information on structure-activity relationships is provided for further rational development and direction of selective synthesis. All models were carried out over a training set including 22 compounds. The best comparative molecular field analysis model only included steric field and had a good Q² = 0.789. Comparative molecular similarity indices analysis overcame the comparative molecular field analysis results: the best comparative molecular similarity indices analysis model also only included steric field and had a Q² = 0.894. In addition, this model predicted adequately the compounds contained in the test set. Furthermore, plots of steric comparative molecular similarity indices analysis field allowed conclusions to be drawn for the choice of suitable inhibitors. In this sense, our model should prove useful in future 15-lipoxygenase inhibitor design studies. © 2010 John Wiley & Sons A/S.

Progress with modeling activity landscapes in drug discovery.

PubMed

Vogt, Martin

2018-04-19

Activity landscapes (ALs) are representations and models of compound data sets annotated with a target-specific activity. In contrast to quantitative structure-activity relationship (QSAR) models, ALs aim at characterizing structure-activity relationships (SARs) on a large-scale level encompassing all active compounds for specific targets. The popularity of AL modeling has grown substantially with the public availability of large activity-annotated compound data sets. AL modeling crucially depends on molecular representations and similarity metrics used to assess structural similarity. Areas covered: The concepts of AL modeling are introduced and its basis in quantitatively assessing molecular similarity is discussed. The different types of AL modeling approaches are introduced. AL designs can broadly be divided into three categories: compound-pair based, dimensionality reduction, and network approaches. Recent developments for each of these categories are discussed focusing on the application of mathematical, statistical, and machine learning tools for AL modeling. AL modeling using chemical space networks is covered in more detail. Expert opinion: AL modeling has remained a largely descriptive approach for the analysis of SARs. Beyond mere visualization, the application of analytical tools from statistics, machine learning and network theory has aided in the sophistication of AL designs and provides a step forward in transforming ALs from descriptive to predictive tools. To this end, optimizing representations that encode activity relevant features of molecules might prove to be a crucial step.

Relationship between self-reported and objectively measured physical activity and subjective memory impairment in breast cancer survivors: role of self-efficacy, fatigue and distress.

PubMed

Phillips, Siobhan M; Lloyd, Gillian R; Awick, Elizabeth A; McAuley, Edward

2017-09-01

Many breast cancer survivors report cancer and cancer treatment-associated cognitive change. However, very little is known about the relationship between physical activity and subjective memory impairment (SMI) in this population. The purpose of this study is to examine the relationship between physical activity and SMI and longitudinally test a model examining the role of self-efficacy, fatigue and distress as potential mediators. Post-treatment breast cancer survivors (N = 1477) completed measures of physical activity, self-efficacy, distress (depression, concerns about recurrence, perceived stress, anxiety), fatigue and SMI at baseline and 6-month follow-up. A subsample (n = 362) was randomly selected to wear an accelerometer. It was hypothesized that physical activity indirectly influences SMI via exercise self-efficacy, distress and fatigue. Relationships were examined using panel analysis within a covariance modeling framework. The hypothesized model provided a good fit in the full sample (χ 2  = 1462.5, df = 469, p = <0.001; CFI = 0.96; SRMR = 0.04) and the accelerometer subsample (χ2 = 961.8, df = 535, p = <0.001, CFI = 0.94, SRMR = 0.05) indicating increased physical activity is indirectly associated with reduction in SMI across time, via increased exercise self-efficacy and reduced distress and fatigue. Higher levels of physical activity, lower levels of fatigue and distress and higher exercise self-efficacy may play an important role in understanding SMI in breast cancer survivors across time. Future research is warranted to replicate and explore these relationships further. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Youth participation in organized and informal sports activities across childhood and adolescence: exploring the relationships of motivational beliefs, developmental stage and gender.

PubMed

Dawes, Nickki Pearce; Vest, Andrea; Simpkins, Sandra

2014-08-01

Involvement in physically active pursuits, such as sports, contributes to achieving and maintaining good emotional and physical health. The central goal of this article was to examine the longitudinal relationships between participation (i.e., time spent in the activities) in organized and informal sports contexts and motivational beliefs, and factors that might impact these relationships, such as developmental stage and gender. The data for the current study were drawn from the childhood and beyond longitudinal study, which utilized a cohort sequential design with data collected on three cohorts across four waves. The current study sample included 986 European American youth (51 % female), who t were mostly from working- and middle-class families. Self-report questionnaires were used to collect data from the youth about their participation in sports and their motivational beliefs (i.e., value and perceptions of competence) about this activity. Structural equation modeling was used to examine the relationships between participation and motivational beliefs across childhood and adolescence. The results provide some support for a model of reciprocal relationships between participation and motivational beliefs in organized and informal sports activities. These relationships between participation and motivational beliefs did not vary significantly based on developmental stage or by gender. Overall, the findings suggest that participation in organized and informal sports contexts may be fostered by supporting the development of positive motivational beliefs about the activities across developmental periods.

Chemical Sensor Array Response Modeling Using Quantitative Structure-Activity Relationships Technique

NASA Astrophysics Data System (ADS)

Shevade, Abhijit V.; Ryan, Margaret A.; Homer, Margie L.; Zhou, Hanying; Manfreda, Allison M.; Lara, Liana M.; Yen, Shiao-Pin S.; Jewell, April D.; Manatt, Kenneth S.; Kisor, Adam K.

We have developed a Quantitative Structure-Activity Relationships (QSAR) based approach to correlate the response of chemical sensors in an array with molecular descriptors. A novel molecular descriptor set has been developed; this set combines descriptors of sensing film-analyte interactions, representing sensor response, with a basic analyte descriptor set commonly used in QSAR studies. The descriptors are obtained using a combination of molecular modeling tools and empirical and semi-empirical Quantitative Structure-Property Relationships (QSPR) methods. The sensors under investigation are polymer-carbon sensing films which have been exposed to analyte vapors at parts-per-million (ppm) concentrations; response is measured as change in film resistance. Statistically validated QSAR models have been developed using Genetic Function Approximations (GFA) for a sensor array for a given training data set. The applicability of the sensor response models has been tested by using it to predict the sensor activities for test analytes not considered in the training set for the model development. The validated QSAR sensor response models show good predictive ability. The QSAR approach is a promising computational tool for sensing materials evaluation and selection. It can also be used to predict response of an existing sensing film to new target analytes.

Quantitative studies on structure-DPPH• scavenging activity relationships of food phenolic acids.

PubMed

Jing, Pu; Zhao, Shu-Juan; Jian, Wen-Jie; Qian, Bing-Jun; Dong, Ying; Pang, Jie

2012-11-01

Phenolic acids are potent antioxidants, yet the quantitative structure-activity relationships of phenolic acids remain unclear. The purpose of this study was to establish 3D-QSAR models able to predict phenolic acids with high DPPH• scavenging activity and understand their structure-activity relationships. The model has been established by using a training set of compounds with cross-validated q2 = 0.638/0.855, non-cross-validated r2 = 0.984/0.986, standard error of estimate = 0.236/0.216, and F = 139.126/208.320 for the best CoMFA/CoMSIA models. The predictive ability of the models was validated with the correlation coefficient r2(pred) = 0.971/0.996 (>0.6) for each model. Additionally, the contour map results suggested that structural characteristics of phenolics acids favorable for the high DPPH• scavenging activity might include: (1) bulky and/or electron-donating substituent groups on the phenol ring; (2) electron-donating groups at the meta-position and/or hydrophobic groups at the meta-/ortho-position; (3) hydrogen-bond donor/electron-donating groups at the ortho-position. The results have been confirmed based on structural analyses of phenolic acids and their DPPH• scavenging data from eight recent publications. The findings may provide deeper insight into the antioxidant mechanisms and provide useful information for selecting phenolic acids for free radical scavenging properties.

Premarital Contraceptive Use: A Test of Two Models

ERIC Educational Resources Information Center

Delamater, John; Maccorquodale, Patricia

1978-01-01

Tests the utility of two models for explaining contraceptive use by sexually active women (N=391). Significant relationships were found between use and permissive premarital standards and standard-behavior consistency. Neither model is particularly applicable to the contraceptive reports of sexually active males (N=354). (Author)

78 FR 4186 - Self-Regulatory Organizations; Financial Industry Regulatory Authority, Inc.; Notice of Filing...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-18

... business models, activities and operations. Further, the requested information will inform FINRA's ongoing... business relationships, business model and compensation. FINRA will accord confidential treatment to the... familiar with the proposed business models, activities and operations of funding portals. Further, the...

Social Relationships, Leisure Activity, and Health in Older Adults

PubMed Central

Chang, Po-Ju; Wray, Linda; Lin, Yeqiang

2015-01-01

Objective Although the link between enhanced social relationships and better health has generally been well established, few studies have examined the role of leisure activity in this link. This study examined how leisure influences the link between social relationships and health in older age. Methods Using data from the 2006 and 2010 waves of the nationally representative U.S. Health and Retirement Study and structural equation modelling analyses, we examined data on 2,965 older participants to determine if leisure activities mediated the link between social relationships and health in 2010, controlling for race, education level, and health in 2006. Results The results demonstrated that leisure activities mediate the link between social relationships and health in these age groups. Perceptions of positive social relationships were associated with greater involvement in leisure activities, and greater involvement in leisure activities was associated with better health in older age. Discussion & Conclusions The contribution of leisure to health in these age groups is receiving increasing attention, and the results of this study add to the literature on this topic, by identifying the mediating effect of leisure activity on the link between social relationships and health. Future studies aimed at increasing leisure activity may contribute to improved health outcomes in older adults. PMID:24884905

Social relationships, leisure activity, and health in older adults.

PubMed

Chang, Po-Ju; Wray, Linda; Lin, Yeqiang

2014-06-01

Although the link between enhanced social relationships and better health has generally been well established, few studies have examined the role of leisure activity in this link. This study examined how leisure influences the link between social relationships and health in older age. Using data from the 2006 and 2010 waves of the nationally representative U.S. Health and Retirement Study and structural equation modeling analyses, we examined data on 2,965 older participants to determine if leisure activities mediated the link between social relationships and health in 2010, controlling for race, education level, and health in 2006. The results demonstrated that leisure activities mediate the link between social relationships and health in these age groups. Perceptions of positive social relationships were associated with greater involvement in leisure activities, and greater involvement in leisure activities was associated with better health in older age. The contribution of leisure to health in these age groups is receiving increasing attention, and the results of this study add to the literature on this topic, by identifying the mediating effect of leisure activity on the link between social relationships and health. Future studies aimed at increasing leisure activity may contribute to improved health outcomes in older adults. PsycINFO Database Record (c) 2014 APA, all rights reserved.

A Three-Dimensional Human Atrial Model with Fiber Orientation. Electrograms and Arrhythmic Activation Patterns Relationship

PubMed Central

Tobón, Catalina; Ruiz-Villa, Carlos A.; Heidenreich, Elvio; Romero, Lucia; Hornero, Fernando; Saiz, Javier

2013-01-01

The most common sustained cardiac arrhythmias in humans are atrial tachyarrhythmias, mainly atrial fibrillation. Areas of complex fractionated atrial electrograms and high dominant frequency have been proposed as critical regions for maintaining atrial fibrillation; however, there is a paucity of data on the relationship between the characteristics of electrograms and the propagation pattern underlying them. In this study, a realistic 3D computer model of the human atria has been developed to investigate this relationship. The model includes a realistic geometry with fiber orientation, anisotropic conductivity and electrophysiological heterogeneity. We simulated different tachyarrhythmic episodes applying both transient and continuous ectopic activity. Electrograms and their dominant frequency and organization index values were calculated over the entire atrial surface. Our simulations show electrograms with simple potentials, with little or no cycle length variations, narrow frequency peaks and high organization index values during stable and regular activity as the observed in atrial flutter, atrial tachycardia (except in areas of conduction block) and in areas closer to ectopic activity during focal atrial fibrillation. By contrast, cycle length variations and polymorphic electrograms with single, double and fragmented potentials were observed in areas of irregular and unstable activity during atrial fibrillation episodes. Our results also show: 1) electrograms with potentials without negative deflection related to spiral or curved wavefronts that pass over the recording point and move away, 2) potentials with a much greater proportion of positive deflection than negative in areas of wave collisions, 3) double potentials related with wave fragmentations or blocking lines and 4) fragmented electrograms associated with pivot points. Our model is the first human atrial model with realistic fiber orientation used to investigate the relationship between different atrial arrhythmic propagation patterns and the electrograms observed at more than 43000 points on the atrial surface. PMID:23408928

Inhibitor-based validation of a homology model of the active-site of tripeptidyl peptidase II.

PubMed

De Winter, Hans; Breslin, Henry; Miskowski, Tamara; Kavash, Robert; Somers, Marijke

2005-04-01

A homology model of the active site region of tripeptidyl peptidase II (TPP II) was constructed based on the crystal structures of four subtilisin-like templates. The resulting model was subsequently validated by judging expectations of the model versus observed activities for a broad set of prepared TPP II inhibitors. The structure-activity relationships observed for the prepared TPP II inhibitors correlated nicely with the structural details of the TPP II active site model, supporting the validity of this model and its usefulness for structure-based drug design and pharmacophore searching experiments.

The Trans-Contextual Model of Autonomous Motivation in Education

PubMed Central

Hagger, Martin S.; Chatzisarantis, Nikos L. D.

2015-01-01

The trans-contextual model outlines the processes by which autonomous motivation toward activities in a physical education context predicts autonomous motivation toward physical activity outside of school, and beliefs about, intentions toward, and actual engagement in, out-of-school physical activity. In the present article, we clarify the fundamental propositions of the model and resolve some outstanding conceptual issues, including its generalizability across multiple educational domains, criteria for its rejection or failed replication, the role of belief-based antecedents of intentions, and the causal ordering of its constructs. We also evaluate the consistency of model relationships in previous tests of the model using path-analytic meta-analysis. The analysis supported model hypotheses but identified substantial heterogeneity in the hypothesized relationships across studies unattributed to sampling and measurement error. Based on our meta-analysis, future research needs to provide further replications of the model in diverse educational settings beyond physical education and test model hypotheses using experimental methods. PMID:27274585

The Trans-Contextual Model of Autonomous Motivation in Education: Conceptual and Empirical Issues and Meta-Analysis.

PubMed

Hagger, Martin S; Chatzisarantis, Nikos L D

2016-06-01

The trans-contextual model outlines the processes by which autonomous motivation toward activities in a physical education context predicts autonomous motivation toward physical activity outside of school, and beliefs about, intentions toward, and actual engagement in, out-of-school physical activity. In the present article, we clarify the fundamental propositions of the model and resolve some outstanding conceptual issues, including its generalizability across multiple educational domains, criteria for its rejection or failed replication, the role of belief-based antecedents of intentions, and the causal ordering of its constructs. We also evaluate the consistency of model relationships in previous tests of the model using path-analytic meta-analysis. The analysis supported model hypotheses but identified substantial heterogeneity in the hypothesized relationships across studies unattributed to sampling and measurement error. Based on our meta-analysis, future research needs to provide further replications of the model in diverse educational settings beyond physical education and test model hypotheses using experimental methods.

Design, synthesis and exploring the quantitative structure-activity relationship of some antioxidant flavonoid analogues.

PubMed

Das, Sreeparna; Mitra, Indrani; Batuta, Shaikh; Niharul Alam, Md; Roy, Kunal; Begum, Naznin Ara

2014-11-01

A series of flavonoid analogues were synthesized and screened for the in vitro antioxidant activity through their ability to quench 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical. The activity of these compounds, measured in comparison to the well-known standard antioxidants (29-32), their precursors (38-42) and other bioactive moieties (38-42) resembling partially the flavone skeleton was analyzed further to develop Quantitative Structure-Activity Relationship (QSAR) models using the Genetic Function Approximation (GFA) technique. Based on the essential structural requirements predicted by the QSAR models, some analogues were designed, synthesized and tested for activity. The predicted and experimental activities of these compounds were well correlated. Flavone analogue 20 was found to be the most potent antioxidant. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modeling the relationship between family home environment factors and parental health.

PubMed

Didericksen, Katharine Wickel; Berge, Jerica M

2015-06-01

Understanding parental health is an important part of understanding family health. Previous research suggests that family meals, familial relationship satisfaction, and family physical activity may separately be related to physical health. The current study aims to combine these variables into a structural equation model to determine the collective relationship they have with adult health within a sample of parents (n = 1,435). Most parents were married, White, and highly educated. The relationship between family meals and parental health was significant (β = -.07, t = -2.29, p < .05), with the full model having adequate fit and accounting for some of the overall variance in parental health. Familial relationship satisfaction and family physical activity were not found to be associated with parental health. Exploratory findings of the sample stratified by biological sex are described. Findings from the current study were consistent with a systemic perspective in that parents may have health benefits when they participate in family-level behavior (e.g., family meals). Additional areas for research and limitations to the current study are also discussed. (c) 2015 APA, all rights reserved).

Influence of perceived sport competence and body attractiveness on physical activity and other healthy lifestyle habits in adolescents.

PubMed

Moreno-Murcia, Juan Antonio; Hellín, Pedro; González-Cutre, David; Martínez-Galindo, Celestina

2011-05-01

The purpose of this study was to test an explanatory model of the relationships between physical self-concept and some healthy habits. A sample of 472 adolescents aged 16 to 20 answered different questionnaires assessing physical self-concept, physical activity, intention to be physically active and consumption of alcohol and tobacco. The results of the structural equation model showed that perceived sport competence positively correlated with current physical activity. Body attractiveness positively correlated with physical activity in boys and negatively in girls. Current physical activity positively correlated with the intention to be physically active in the future and negatively with the consumption of alcohol and tobacco. Nevertheless, this last relationship was only significant in boys. The results are discussed in connection with the promotion of healthy lifestyle guidelines among adolescents. This model shows the importance of physical self-concept for engaging in physical activity in adolescence. It also suggests that physical activity is associated with the intention to continue being physically active and with healthy lifestyle habits.

Design of cinnamaldehyde amino acid Schiff base compounds based on the quantitative structure-activity relationship.

PubMed

Wang, Hui; Jiang, Mingyue; Li, Shujun; Hse, Chung-Yun; Jin, Chunde; Sun, Fangli; Li, Zhuo

2017-09-01

Cinnamaldehyde amino acid Schiff base (CAAS) is a new class of safe, bioactive compounds which could be developed as potential antifungal agents for fungal infections. To design new cinnamaldehyde amino acid Schiff base compounds with high bioactivity, the quantitative structure-activity relationships (QSARs) for CAAS compounds against Aspergillus niger ( A. niger ) and Penicillium citrinum (P. citrinum) were analysed. The QSAR models ( R 2  = 0.9346 for A. niger , R 2  = 0.9590 for P. citrinum, ) were constructed and validated. The models indicated that the molecular polarity and the Max atomic orbital electronic population had a significant effect on antifungal activity. Based on the best QSAR models, two new compounds were designed and synthesized. Antifungal activity tests proved that both of them have great bioactivity against the selected fungi.

Design of cinnamaldehyde amino acid Schiff base compounds based on the quantitative structure–activity relationship

PubMed Central

Wang, Hui; Jiang, Mingyue; Hse, Chung-Yun; Jin, Chunde; Sun, Fangli; Li, Zhuo

2017-01-01

Cinnamaldehyde amino acid Schiff base (CAAS) is a new class of safe, bioactive compounds which could be developed as potential antifungal agents for fungal infections. To design new cinnamaldehyde amino acid Schiff base compounds with high bioactivity, the quantitative structure–activity relationships (QSARs) for CAAS compounds against Aspergillus niger (A. niger) and Penicillium citrinum (P. citrinum) were analysed. The QSAR models (R2 = 0.9346 for A. niger, R2 = 0.9590 for P. citrinum,) were constructed and validated. The models indicated that the molecular polarity and the Max atomic orbital electronic population had a significant effect on antifungal activity. Based on the best QSAR models, two new compounds were designed and synthesized. Antifungal activity tests proved that both of them have great bioactivity against the selected fungi. PMID:28989758

Exploring Behavioral Markers of Long-Term Physical Activity Maintenance: A Case Study of System Identification Modeling within a Behavioral Intervention

ERIC Educational Resources Information Center

Hekler, Eric B.; Buman, Matthew P.; Poothakandiyil, Nikhil; Rivera, Daniel E.; Dzierzewski, Joseph M.; Aiken Morgan, Adrienne; McCrae, Christina S.; Roberts, Beverly L.; Marsiske, Michael; Giacobbi, Peter R., Jr.

2013-01-01

Efficacious interventions to promote long-term maintenance of physical activity are not well understood. Engineers have developed methods to create dynamical system models for modeling idiographic (i.e., within-person) relationships within systems. In behavioral research, dynamical systems modeling may assist in decomposing intervention effects…

Pedagogical Catalysts of Civic Competence: The Development of a Critical Epistemological Model for Community-Based Learning

ERIC Educational Resources Information Center

Stokamer, Stephanie

2013-01-01

Democratic problem-solving necessitates an active and informed citizenry, but existing research on service-learning has shed little light on the relationship between pedagogical practices and civic competence outcomes. This study developed and tested a model to represent that relationship and identified pedagogical catalysts of civic competence…

Imidazole derivatives as angiotensin II AT1 receptor blockers: Benchmarks, drug-like calculations and quantitative structure-activity relationships modeling

NASA Astrophysics Data System (ADS)

Alloui, Mebarka; Belaidi, Salah; Othmani, Hasna; Jaidane, Nejm-Eddine; Hochlaf, Majdi

2018-03-01

We performed benchmark studies on the molecular geometry, electron properties and vibrational analysis of imidazole using semi-empirical, density functional theory and post Hartree-Fock methods. These studies validated the use of AM1 for the treatment of larger systems. Then, we treated the structural, physical and chemical relationships for a series of imidazole derivatives acting as angiotensin II AT1 receptor blockers using AM1. QSAR studies were done for these imidazole derivatives using a combination of various physicochemical descriptors. A multiple linear regression procedure was used to design the relationships between molecular descriptor and the activity of imidazole derivatives. Results validate the derived QSAR model.

A test of an expert-based bird-habitat relationship model in South Carolina

Treesearch

John C. Kilgo; David L. Gartner; Brian R. Chapman; John B. Dunnin; Kathleen E. Franzreb; Sidney A. Gauthreaux; Cathryn H. Greenberg; Douglas J. Levey; Karl V. Miller; Scott F. Pearson

2002-01-01

Wildlife-habitat relationships models are used widely by land managers to provide information on which species are likely to occur in an area of interest and may be impacted by a proposed management activity. Few such models have been tested. We used recent avian census data from the Savannah River Site, South Carolina to validate BIRDHAB, a geographic information...

Self-efficacy and pain acceptance as mediators of the relationship between pain and performance of valued life activities in women and men with rheumatoid arthritis.

PubMed

Ahlstrand, Inger; Vaz, Sharmila; Falkmer, Torbjörn; Thyberg, Ingrid; Björk, Mathilda

2017-06-01

To study whether personal factors (self-efficacy and pain acceptance) mediate the relationship between pain and performance of valued life activities in persons with rheumatoid arthritis. Persons with rheumatoid arthritis for at least four years ( n = 737; 73% women) answered a questionnaire measuring self-efficacy, pain acceptance, performance of valued life activities, and self-rated pain. Relationships among these constructs were explored using univariate and multivariate analyses. Structural equation modelling was then used to examine the mediational role of personal factors on the relationship between pain and performance of valued life activities. A direct negative association between pain and performance of valued life activities was identified ( Beta = .34, P < .001). This suggests that people with rheumatoid arthritis who had higher levels of pain has increased difficulties in performing valued life activities. Self-efficacy and activity engagement component of pain acceptance mediated the relationship between pain and performance of valued life activities, however the pain willingness component of pain acceptance did not influence participation in valued life activities. These findings highlight the importance of considering personal factors, such as pain acceptance and self-efficacy, in facilitating participation in valued life activities.

Biological activity of aldose reductase and lipophilicity of pyrrolyl-acetic acid derivatives

NASA Astrophysics Data System (ADS)

Kumari, A.; Kumari, R.; Kumar, R.; Gupta, M.

2011-12-01

Quantitative Structure-Activity Relationship modeling is a powerful approach for correlating an organic compound to its lipophilicity. In this paper QSAR models are established for estimation of correlation of the lipophilicity of a series of pyrrolyl-acetic acid derivatives, inhibitors of the aldose reductase enzyme, in the n-octanol-water system with biological activity of aldose reductase. Lipophilicity, expressed by the logarithm of n-octnol-water partition coefficient log P and biological activity of aldose reductase inhibitory activity by log it. Result obtained by QSAR modeling of compound series reveal a definite trend in biological activity and a further improvement in quantitative relationships are established if, beside log P, Hammett electronic constant σ and connectivity index chi-3 (3 χ) term included in the regression equation. The tri-parametric model with log P, 3 χ and σ as correlating parameters have been found to be the best which gives a variance of 87% ( R 2 = 0.8743). A compound has been found to be serious outlier and when the same has been excluded the model explains about 94% variance of the data set ( R 2 = 0.9447). The topological index (3 χ) has been found to be a good parameter for modeling the biological activity.

Prediction of Environmental Impact of High-Energy Materials with Atomistic Computer Simulations

DTIC Science & Technology

2010-11-01

from a training set of compounds. Other methods include Quantitative Struc- ture-Activity Relationship ( QSAR ) and Quantitative Structure-Property...26 28 the development of QSPR/ QSAR models, in contrast to boiling points and critical parameters derived from empirical correlations, to improve...Quadratic Configuration Interaction Singles Doubles QSAR Quantitative Structure-Activity Relationship QSPR Quantitative Structure-Property

AutoQSAR: an automated machine learning tool for best-practice quantitative structure-activity relationship modeling.

PubMed

Dixon, Steven L; Duan, Jianxin; Smith, Ethan; Von Bargen, Christopher D; Sherman, Woody; Repasky, Matthew P

2016-10-01

We introduce AutoQSAR, an automated machine-learning application to build, validate and deploy quantitative structure-activity relationship (QSAR) models. The process of descriptor generation, feature selection and the creation of a large number of QSAR models has been automated into a single workflow within AutoQSAR. The models are built using a variety of machine-learning methods, and each model is scored using a novel approach. Effectiveness of the method is demonstrated through comparison with literature QSAR models using identical datasets for six end points: protein-ligand binding affinity, solubility, blood-brain barrier permeability, carcinogenicity, mutagenicity and bioaccumulation in fish. AutoQSAR demonstrates similar or better predictive performance as compared with published results for four of the six endpoints while requiring minimal human time and expertise.

An application and extension of the constraints–effects–mitigation model to Minnesota waterfowl hunting

USGS Publications Warehouse

Schroeder, Susan A.; Fulton, David C.; Lawrence, Jeffrey S.; Cordts, Steven D.

2012-01-01

This study extends modeling work on the leisure constraint negotiation process from physically active leisure and celebrity fandom to hunting. We test a model derived from the constraints–effects–mitigation model of leisure participation. The model is examined in the context of continued Minnesota waterfowl hunting among a sample of Minnesota residents who purchased a North Dakota waterfowl stamp. Results are from a mail survey conducted in 2006. In our modeling, successful constraint negotiation fully mediated the constraints–participation relationship, while involvement had both direct and indirect effects on participation. Hunter motivation was positively related to involvement. Results advance understanding of the relationships among factors that influence leisure participation, and suggest that constraint negotiation may differ among recreation activities with different participant profiles.

Explaining the Relationship Between Sexually Explicit Internet Material and Casual Sex: A Two-Step Mediation Model.

PubMed

Vandenbosch, Laura; van Oosten, Johanna M F

2018-07-01

Despite increasing interest in the implications of adolescents' use of sexually explicit Internet material (SEIM), we still know little about the relationship between SEIM use and adolescents' casual sexual activities. Based on a three-wave online panel survey study among Dutch adolescents (N = 1079; 53.1% boys; 93.5% with an exclusively heterosexual orientation; M age  = 15.11; SD = 1.39), we found that watching SEIM predicted engagement in casual sex over time. In turn, casual sexual activities partially predicted adolescents' use of SEIM. A two-step mediation model was tested to explain the relationship between watching SEIM and casual sex. It was partially confirmed. First, watching SEIM predicted adolescents' perceptions of SEIM as a relevant information source from Wave 2 to Wave 3, but not from Wave 1 to Wave 2. Next, such perceived utility of SEIM was positively related to stronger instrumental attitudes toward sex and thus their views about sex as a core instrument for sexual gratification. Lastly, adolescents' instrumental attitudes toward sex predicted adolescents' engagement in casual sex activities consistently across waves. Partial support emerged for a reciprocal relationship between watching SEIM and perceived utility. We did not find a reverse relationship between casual sex activities and instrumental attitudes toward sex. No significant gender differences emerged.

Effects of pretesting with the Adventure Recreation Model instrument

Treesearch

Anderson Young; Lynn Anderson; Dale Anderson

2002-01-01

The Adventure Recreation Model, first proposed and tested by Ewert and Hollenhorst (1989), attempts to describe participant characteristics and patterns of use in adventure recreation activities. The Adventure Recreation Model is based on the relationship of level of engagement in an outdoor recreation activity (ranging from beginner, to development, to commitment)...

Novel Uses of In Vitro Data to Develop Quantitative Biological Activity Relationship Models for in Vivo Carcinogenicity Prediction.

PubMed

Pradeep, Prachi; Povinelli, Richard J; Merrill, Stephen J; Bozdag, Serdar; Sem, Daniel S

2015-04-01

The availability of large in vitro datasets enables better insight into the mode of action of chemicals and better identification of potential mechanism(s) of toxicity. Several studies have shown that not all in vitro assays can contribute as equal predictors of in vivo carcinogenicity for development of hybrid Quantitative Structure Activity Relationship (QSAR) models. We propose two novel approaches for the use of mechanistically relevant in vitro assay data in the identification of relevant biological descriptors and development of Quantitative Biological Activity Relationship (QBAR) models for carcinogenicity prediction. We demonstrate that in vitro assay data can be used to develop QBAR models for in vivo carcinogenicity prediction via two case studies corroborated with firm scientific rationale. The case studies demonstrate the similarities between QBAR and QSAR modeling in: (i) the selection of relevant descriptors to be used in the machine learning algorithm, and (ii) the development of a computational model that maps chemical or biological descriptors to a toxic endpoint. The results of both the case studies show: (i) improved accuracy and sensitivity which is especially desirable under regulatory requirements, and (ii) overall adherence with the OECD/REACH guidelines. Such mechanism based models can be used along with QSAR models for prediction of mechanistically complex toxic endpoints. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physical Activity in Advanced Age: Physical Activity, Function, and Mortality in Advanced Age: A Longitudinal Follow Up (LiLACS NZ).

PubMed

Mace Firebaugh, Casey; Moyes, Simon; Jatrana, Santosh; Rolleston, Anna; Kerse, Ngaire

2018-01-18

The relationship between physical activity, function, and mortality is not established in advanced age. Physical activity, function, and mortality were followed in a cohort of Māori and non-Māori adults living in advanced age for a period of six years. Generalised Linear regression models were used to analyse the association between physical activity and NEADL while Kaplan-Meier survival analysis, and Cox-proportional hazard models were used to assess the association between the physical activity and mortality. The Hazard Ratio for mortality for those in the least active physical activity quartile was 4.1 for Māori and 1.8 for non- Māori compared to the most active physical activity quartile. There was an inverse relationship between physical activity and mortality, with lower hazard ratios for mortality at all levels of physical activity. Higher levels of physical activity were associated with lower mortality and higher functional status in advanced aged adults.

Obscure phenomena in statistical analysis of quantitative structure-activity relationships. Part 1: Multicollinearity of physicochemical descriptors.

PubMed

Mager, P P; Rothe, H

1990-10-01

Multicollinearity of physicochemical descriptors leads to serious consequences in quantitative structure-activity relationship (QSAR) analysis, such as incorrect estimators and test statistics of regression coefficients of the ordinary least-squares (OLS) model applied usually to QSARs. Beside the diagnosis of the known simple collinearity, principal component regression analysis (PCRA) also allows the diagnosis of various types of multicollinearity. Only if the absolute values of PCRA estimators are order statistics that decrease monotonically, the effects of multicollinearity can be circumvented. Otherwise, obscure phenomena may be observed, such as good data recognition but low predictive model power of a QSAR model.

Use it or lose it: engaged lifestyle as a buffer of cognitive decline in aging?

PubMed

Hultsch, D F; Hertzog, C; Small, B J; Dixon, R A

1999-06-01

Data from the Victoria Longitudinal Study were used to examine the hypothesis that maintaining intellectual engagement through participation in everyday activities buffers individuals against cognitive decline in later life. The sample consisted of 250 middle-aged and older adults tested 3 times over 6 years. Structural equation modeling techniques were used to examine the relationships among changes in lifestyle variables and an array of cognitive variables. There was a relationship between changes in intellectually related activities and changes in cognitive functioning. These results are consistent with the hypothesis that intellectually engaging activities serve to buffer individuals against decline. However, an alternative model suggested the findings were also consistent with the hypothesis that high-ability individuals lead intellectually active lives until cognitive decline in old age limits their activities.

Decoding the Semantic Content of Natural Movies from Human Brain Activity

PubMed Central

Huth, Alexander G.; Lee, Tyler; Nishimoto, Shinji; Bilenko, Natalia Y.; Vu, An T.; Gallant, Jack L.

2016-01-01

One crucial test for any quantitative model of the brain is to show that the model can be used to accurately decode information from evoked brain activity. Several recent neuroimaging studies have decoded the structure or semantic content of static visual images from human brain activity. Here we present a decoding algorithm that makes it possible to decode detailed information about the object and action categories present in natural movies from human brain activity signals measured by functional MRI. Decoding is accomplished using a hierarchical logistic regression (HLR) model that is based on labels that were manually assigned from the WordNet semantic taxonomy. This model makes it possible to simultaneously decode information about both specific and general categories, while respecting the relationships between them. Our results show that we can decode the presence of many object and action categories from averaged blood-oxygen level-dependent (BOLD) responses with a high degree of accuracy (area under the ROC curve > 0.9). Furthermore, we used this framework to test whether semantic relationships defined in the WordNet taxonomy are represented the same way in the human brain. This analysis showed that hierarchical relationships between general categories and atypical examples, such as organism and plant, did not seem to be reflected in representations measured by BOLD fMRI. PMID:27781035

Selective CB2 receptor agonists. Part 2: Structure-activity relationship studies and optimization of proline-based compounds.

PubMed

Riether, Doris; Zindell, Renee; Wu, Lifen; Betageri, Raj; Jenkins, James E; Khor, Someina; Berry, Angela K; Hickey, Eugene R; Ermann, Monika; Albrecht, Claudia; Ceci, Angelo; Gemkow, Mark J; Nagaraja, Nelamangala V; Romig, Helmut; Sauer, Achim; Thomson, David S

2015-02-01

Through a ligand-based pharmacophore model (S)-proline based compounds were identified as potent cannabinoid receptor 2 (CB2) agonists with high selectivity over the cannabinoid receptor 1 (CB1). Structure-activity relationship investigations for this compound class lead to oxo-proline compounds 21 and 22 which combine an impressive CB1 selectivity profile with good pharmacokinetic properties. In a streptozotocin induced diabetic neuropathy model, 22 demonstrated a dose-dependent reversal of mechanical hyperalgesia. Copyright © 2014 Elsevier Ltd. All rights reserved.

Investigation on Quantitative Structure Activity Relationships of a Series of Inducible Nitric Oxide.

PubMed

Sharma, Mukesh C; Sharma, S

2016-12-01

A series of 2-dihydro-4-quinazolin with potent highly selective inhibitors of inducible nitric oxide synthase activities was subjected to quantitative structure activity relationships (QSAR) analysis. Statistically significant equations with high correlation coefficient (r 2  = 0.8219) were developed. The k-nearest neighbor model has showed good cross-validated correlation coefficient and external validation values of 0.7866 and 0.7133, respectively. The selected electrostatic field descriptors the presence of blue ball around R1 and R4 in the quinazolinamine moiety showed electronegative groups favorable for nitric oxide synthase activity. The QSAR models may lead to the structural requirements of inducible nitric oxide compounds and help in the design of new compounds.

Proximal and Distal Outcomes of Organizational Socialization among New Teachers: A Mediation Analysis

ERIC Educational Resources Information Center

Tengku Ariffin, Tengku Faekah; Awang Hashim, Rosna; Yusof, Norhafezah

2014-01-01

This study was designed to examine the relationship between socialization experience and the task performance of new teachers. It proposed to do this by testing a structural model. In explicating the relationship between the two constructs, teacher engagement in workplace learning activities and wellbeing were included in the structural model as…

A Comparison of Linear and Systems Thinking Approaches for Program Evaluation Illustrated Using the Indiana Interdisciplinary GK-12

ERIC Educational Resources Information Center

Dyehouse, Melissa; Bennett, Deborah; Harbor, Jon; Childress, Amy; Dark, Melissa

2009-01-01

Logic models are based on linear relationships between program resources, activities, and outcomes, and have been used widely to support both program development and evaluation. While useful in describing some programs, the linear nature of the logic model makes it difficult to capture the complex relationships within larger, multifaceted…

Molecular design of anticancer drug leads based on three-dimensional quantitative structure-activity relationship.

PubMed

Huang, Xiao Yan; Shan, Zhi Jie; Zhai, Hong Lin; Li, Li Na; Zhang, Xiao Yun

2011-08-22

Heat shock protein 90 (Hsp90) takes part in the developments of several cancers. Novobiocin, a typically C-terminal inhibitor for Hsp90, will probably used as an important anticancer drug in the future. In this work, we explored the valuable information and designed new novobiocin derivatives based on a three-dimensional quantitative structure-activity relationship (3D QSAR). The comparative molecular field analysis and comparative molecular similarity indices analysis models with high predictive capability were established, and their reliabilities are supported by the statistical parameters. Based on the several important influence factors obtained from these models, six new novobiocin derivatives with higher inhibitory activities were designed and confirmed by the molecular simulation with our models, which provide the potential anticancer drug leads for further research.

A Logic Model for Community Engagement within the CTSA Consortium: Can We Measure What We Model?

PubMed Central

Eder, Milton Mickey; Carter-Edwards, Lori; Hurd, Thelma C.; Rumala, Bernice B.; Wallerstein, Nina

2013-01-01

The Clinical Translation Science Award (CTSA) initiative calls upon academic health centers to engage communities around a clinical research relationship measured ultimately in terms of public health. Among a few initiatives involving university accountability for advancing public interests, a small CTSA workgroup devised a community engagement (CE) logic model that organizes common activities within a university-community infrastructure to facilitate community engagement in research. While the model focuses on the range of institutional CE inputs, it purposefully does not include an approach for assessing how community engagement influences research implementation and outcomes. Rather, with communities and individuals beginning to transition into new research roles, this article emphasizes studying community engagement through specific relationship types and assessing how expanded research teams contribute to the full spectrum of translational science. The authors propose a typology consisting of three relationship types—engagement, collaboration and shared leadership—to provide a foundation for investigating community–academic contributions to the new CTSA research paradigm. The typology shifts attention from specific community–academic activities and, instead, encourages analyses focused on measuring the strength of relationships through variables like synergy and trust. The collaborative study of CE relationships will inform an understanding of CTSA infrastructure development in support of translational research and its goal, which is expressed in the logic model: better science, better answers, better population health. PMID:23752038

QSAR study of anthranilic acid sulfonamides as inhibitors of methionine aminopeptidase-2 using LS-SVM and GRNN based on principal components.

PubMed

Shahlaei, Mohsen; Sabet, Razieh; Ziari, Maryam Bahman; Moeinifard, Behzad; Fassihi, Afshin; Karbakhsh, Reza

2010-10-01

Quantitative relationships between molecular structure and methionine aminopeptidase-2 inhibitory activity of a series of cytotoxic anthranilic acid sulfonamide derivatives were discovered. We have demonstrated the detailed application of two efficient nonlinear methods for evaluation of quantitative structure-activity relationships of the studied compounds. Components produced by principal component analysis as input of developed nonlinear models were used. The performance of the developed models namely PC-GRNN and PC-LS-SVM were tested by several validation methods. The resulted PC-LS-SVM model had a high statistical quality (R(2)=0.91 and R(CV)(2)=0.81) for predicting the cytotoxic activity of the compounds. Comparison between predictability of PC-GRNN and PC-LS-SVM indicates that later method has higher ability to predict the activity of the studied molecules. Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.

Quantitative structure-property relationship (correlation analysis) of phosphonic acid-based chelates in design of MRI contrast agent.

PubMed

Tiwari, Anjani K; Ojha, Himanshu; Kaul, Ankur; Dutta, Anupama; Srivastava, Pooja; Shukla, Gauri; Srivastava, Rakesh; Mishra, Anil K

2009-07-01

Nuclear magnetic resonance imaging is a very useful tool in modern medical diagnostics, especially when gadolinium (III)-based contrast agents are administered to the patient with the aim of increasing the image contrast between normal and diseased tissues. With the use of soft modelling techniques such as quantitative structure-activity relationship/quantitative structure-property relationship after a suitable description of their molecular structure, we have studied a series of phosphonic acid for designing new MRI contrast agent. Quantitative structure-property relationship studies with multiple linear regression analysis were applied to find correlation between different calculated molecular descriptors of the phosphonic acid-based chelating agent and their stability constants. The final quantitative structure-property relationship mathematical models were found as--quantitative structure-property relationship Model for phosphonic acid series (Model 1)--log K(ML) = {5.00243(+/-0.7102)}- MR {0.0263(+/-0.540)}n = 12 l r l = 0.942 s = 0.183 F = 99.165 quantitative structure-property relationship Model for phosphonic acid series (Model 2)--log K(ML) = {5.06280(+/-0.3418)}- MR {0.0252(+/- .198)}n = 12 l r l = 0.956 s = 0.186 F = 99.256.

Self-efficacy and physical activity in adolescent and parent dyads.

PubMed

Rutkowski, Elaine M; Connelly, Cynthia D

2012-01-01

The study examined the relationships between self-efficacy and physical activity in adolescent and parent dyads. A cross-sectional, correlational design was used to explore the relationships among levels of parent physical activity, parent-adolescent self-efficacy, and adolescent physical activity. Descriptive and multivariate regression analyses were conducted in a purposive sample of 94 adolescent/parent dyads. Regression results indicated the overall model significantly predicted adolescent physical activity (R(2) = .20, R(2)(adj) = .14, F[5, 70]= 3.28, p= .01). Only one of the five predictor variables significantly contributed to the model. Higher levels of adolescent self-efficacy was positively related to greater levels of adolescent physical activity (β= .29, p= .01). Practitioners are encouraged to examine the level of self-efficacy and physical activity in families in an effort to develop strategies that impact these areas and ultimately to mediate obesity-related challenges in families seeking care. © 2011, Wiley Periodicals, Inc.

HomoSAR: bridging comparative protein modeling with quantitative structural activity relationship to design new peptides.

PubMed

Borkar, Mahesh R; Pissurlenkar, Raghuvir R S; Coutinho, Evans C

2013-11-15

Peptides play significant roles in the biological world. To optimize activity for a specific therapeutic target, peptide library synthesis is inevitable; which is a time consuming and expensive. Computational approaches provide a promising way to simply elucidate the structural basis in the design of new peptides. Earlier, we proposed a novel methodology termed HomoSAR to gain insight into the structure activity relationships underlying peptides. Based on an integrated approach, HomoSAR uses the principles of homology modeling in conjunction with the quantitative structural activity relationship formalism to predict and design new peptide sequences with the optimum activity. In the present study, we establish that the HomoSAR methodology can be universally applied to all classes of peptides irrespective of sequence length by studying HomoSAR on three peptide datasets viz., angiotensin-converting enzyme inhibitory peptides, CAMEL-s antibiotic peptides, and hAmphiphysin-1 SH3 domain binding peptides, using a set of descriptors related to the hydrophobic, steric, and electronic properties of the 20 natural amino acids. Models generated for all three datasets have statistically significant correlation coefficients (r(2)) and predictive r2 (r(pred)2) and cross validated coefficient ( q(LOO)2). The daintiness of this technique lies in its simplicity and ability to extract all the information contained in the peptides to elucidate the underlying structure activity relationships. The difficulties of correlating both sequence diversity and variation in length of the peptides with their biological activity can be addressed. The study has been able to identify the preferred or detrimental nature of amino acids at specific positions in the peptide sequences. Copyright © 2013 Wiley Periodicals, Inc.

Smart teens don't have sex (or kiss much either).

PubMed

Halpern, C T; Joyner, K; Udry, J R; Suchindran, C

2000-03-01

To examine the relationship between an intelligence measure and a wide spectrum of partnered sexual activity ranging from holding hands to sexual intercourse among adolescents. Analyses are based on two separate samples of adolescents. The core sample of the National Longitudinal Study of Adolescent Health (Add Health) includes approximately 12,000 adolescents enrolled in the 7th to 12th grades. The Biosocial Factors in Adolescent Development projects followed approximately 100 white males and 200 black and white females over 3- and 2-year periods, respectively. Both studies used the Peabody Picture Vocabulary Test (PPVT) as an intelligence measure, and confidential self-reports of sexual activity. Logistic regression models were used to examine the relationship between PPVT scores and coital status in Add Health data; proportional hazard models were used to examine the timing of initiation of noncoital and coital activities as a function of PPVT scores in the Biosocial Factors sample. Controlling for age, physical maturity, and mother's education, a significant curvilinear relationship between intelligence and coital status was demonstrated; adolescents at the upper and lower ends of the intelligence distribution were less likely to have sex. Higher intelligence was also associated with postponement of the initiation of the full range of partnered sexual activities. An expanded model incorporating a variety of control and mediator variables was tested to identify mechanisms by which the relationship operates. Higher intelligence operates as a protective factor against early sexual activity during adolescence, and lower intelligence, to a point, is a risk factor. More systematic investigation of the implications of individual differences in cognitive abilities for sexual activities and of the processes that underlie those activities is warranted.

Evaluating and Refining the Conceptual Model Used in the Study of Health and Activity in Preschool Environments (SHAPES) Intervention

ERIC Educational Resources Information Center

Saunders, Ruth P.; Pfeiffer, Karin; Brown, William H.; Howie, Erin K.; Dowda, Marsha; O'Neill, Jennifer R.; McIver, Kerry; Pate, Russell R.

2017-01-01

This study investigated the utility of the Study of Health and Activity in Preschool Environments (SHAPES) conceptual model, which targeted physical activity (PA) behavior in preschool children, by examining the relationship between implementation monitoring data and child PA during the school day. We monitored implementation completeness and…

Brain activity and cognition: a connection from thermodynamics and information theory.

PubMed

Collell, Guillem; Fauquet, Jordi

2015-01-01

The connection between brain and mind is an important scientific and philosophical question that we are still far from completely understanding. A crucial point to our work is noticing that thermodynamics provides a convenient framework to model brain activity, whereas cognition can be modeled in information-theoretical terms. In fact, several models have been proposed so far from both approaches. A second critical remark is the existence of deep theoretical connections between thermodynamics and information theory. In fact, some well-known authors claim that the laws of thermodynamics are nothing but principles in information theory. Unlike in physics or chemistry, a formalization of the relationship between information and energy is currently lacking in neuroscience. In this paper we propose a framework to connect physical brain and cognitive models by means of the theoretical connections between information theory and thermodynamics. Ultimately, this article aims at providing further insight on the formal relationship between cognition and neural activity.

Development of a Conceptual Model to Predict Physical Activity Participation in Adults with Brain Injuries

ERIC Educational Resources Information Center

Driver, Simon

2008-01-01

The purpose was to examine psychosocial factors that influence the physical activity behaviors of adults with brain injuries. Two differing models, based on Harter's model of self-worth, were proposed to examine the relationship between perceived competence, social support, physical self-worth, affect, and motivation. Adults numbering 384 with…

Do Perceptions of Competence Mediate The Relationship Between Fundamental Motor Skill Proficiency and Physical Activity Levels of Children in Kindergarten?

PubMed

Crane, Jeff R; Naylor, Patti J; Cook, Ryan; Temple, Viviene A

2015-07-01

Perceptions of competence mediate the relationship between motor skill proficiency and physical activity among older children and adolescents. This study examined kindergarten children's perceptions of physical competence as a mediator of the relationship between motor skill proficiency as a predictor variable and physical activity levels as the outcome variable; and also with physical activity as a predictor and motor skill proficiency as the outcome. Participants were 116 children (mean age = 5 years 7 months, 58% boys) from 10 schools. Motor skills were measured using the Test of Gross Motor Development-2 and physical activity was monitored through accelerometry. Perceptions of physical competence were measured using The Pictorial Scale of Perceived Competence and Social Acceptance for Young Children, and the relationships between these variables were examined using a model of mediation. The direct path between object control skills and moderate-vigorous physical activity (MVPA) was significant and object control skills predicted perceived physical competence. However, perceived competence did not mediate the relationship between object control skills and MVPA. The significant relationship between motor proficiency and perceptions of competence did not in turn influence kindergarten children's participation in physical activity. These findings support concepts of developmental differences in the structure of the self-perception system.

Preconditioning electromyographic data for an upper extremity model using neural networks

NASA Technical Reports Server (NTRS)

Roberson, D. J.; Fernjallah, M.; Barr, R. E.; Gonzalez, R. V.

1994-01-01

A back propagation neural network has been employed to precondition the electromyographic signal (EMG) that drives a computational model of the human upper extremity. This model is used to determine the complex relationship between EMG and muscle activation, and generates an optimal muscle activation scheme that simulates the actual activation. While the experimental and model predicted results of the ballistic muscle movement are very similar, the activation function between the start and the finish is not. This neural network preconditions the signal in an attempt to more closely model the actual activation function over the entire course of the muscle movement.

The gender role motivation model of women's sexually submissive behavior and satisfaction in heterosexual couples.

PubMed

Sanchez, Diana T; Phelan, Julie E; Moss-Racusin, Corinne A; Good, Jessica J

2012-04-01

Previous findings suggest that women are more likely than men to take on the submissive role during sexual activities (e.g., waiting for their partner to initiate and orchestrate sexual activities), often to the detriment of their sexual satisfaction. Extending previous research on gender role motivation, the authors recruited 181 heterosexual couples to examine scripted sexual behavior, motivation for such behavior, and relationship outcomes (sexual satisfaction, perceptions of closeness, and relationship satisfaction) for both women and their partners. Using the actor-partner interdependence model, path analyses revealed that women's submissive behavior had negative links to personal sexual satisfaction and their partner's sexual satisfaction but only when their submission was inconsistent with their sexual preferences. Moreover, the authors show there are negative downstream consequences of diminished sexual satisfaction on perceptions of closeness and overall relationship satisfaction for both partners in the relationship.

Quantitative structure-activity relationship modeling on in vitro endocrine effects and metabolic stability involving 26 selected brominated flame retardants.

PubMed

Harju, Mikael; Hamers, Timo; Kamstra, Jorke H; Sonneveld, Edwin; Boon, Jan P; Tysklind, Mats; Andersson, Patrik L

2007-04-01

In this work, quantitative structure-activity relationships (QSARs) were developed to aid human and environmental risk assessment processes for brominated flame retardants (BFRs). Brominated flame retardants, such as the high-production-volume chemicals polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A, and hexabromocyclododecane, have been identified as potential endocrine disruptors. Quantitative structure-activity relationship models were built based on the in vitro potencies of 26 selected BFRs. The in vitro assays included interactions with, for example, androgen, progesterone, estrogen, and dioxin (aryl hydrocarbon) receptor, plus competition with thyroxine for its plasma carrier protein (transthyretin), inhibition of estradiol sulfation via sulfotransferase, and finally, rate of metabolization. The QSAR modeling, a number of physicochemical parameters were calculated describing the electronic, lipophilic, and structural characteristics of the molecules. These include frontier molecular orbitals, molecular charges, polarities, log octanol/water partitioning coefficient, and two- and three-dimensional molecularproperties. Experimental properties were included and measured for PBDEs, such as their individual ultraviolet spectra (200-320 nm) and retention times on three different high-performance liquid chromatography columns and one nonpolar gas chromatography column. Quantitative structure-activity relationship models based on androgen antagonism and metabolic degradation rates generally gave similar results, suggesting that lower-brominated PBDEs with bromine substitutions in ortho positions and bromine-free meta- and para positions had the highest potencies and metabolic degradation rates. Predictions made for the constituents of the technical flame retardant Bromkal 70-5DE found BDE 17 to be a potent androgen antagonist and BDE 66, which is a relevant PBDE in environmental samples, to be only a weak antagonist.

The Relationship between Pedal Force and Crank Angular Velocity in Sprint Cycling.

PubMed

Bobbert, Maarten Frank; Casius, L J Richard; Van Soest, Arthur J

2016-05-01

Relationships between tangential pedal force and crank angular velocity in sprint cycling tend to be linear. We set out to understand why they are not hyperbolic, like the intrinsic force-velocity relationship of muscles. We simulated isokinetic sprint cycling at crank angular velocities ranging from 30 to 150 rpm with a forward dynamic model of the human musculoskeletal system actuated by eight lower extremity muscle groups. The input of the model was muscle stimulation over time, which we optimized to maximize average power output over a cycle. Peak tangential pedal force was found to drop more with crank angular velocity than expected based on intrinsic muscle properties. This linearizing effect was not due to segmental dynamics but rather due to active state dynamics. Maximizing average power in cycling requires muscles to bring their active state from as high as possible during shortening to as low as possible during lengthening. Reducing the active state is a relatively slow process, and hence must be initiated a certain amount of time before lengthening starts. As crank angular velocity goes up, this amount of time corresponds to a greater angular displacement, so the instant of switching off extensor muscle stimulation must occur earlier relative to the angle at which pedal force was extracted for the force-velocity relationship. Relationships between pedal force and crank angular velocity in sprint cycling do not reflect solely the intrinsic force-velocity relationship of muscles but also the consequences of activation dynamics.

Partitioning and lipophilicity in quantitative structure-activity relationships.

PubMed Central

Dearden, J C

1985-01-01

The history of the relationship of biological activity to partition coefficient and related properties is briefly reviewed. The dominance of partition coefficient in quantitation of structure-activity relationships is emphasized, although the importance of other factors is also demonstrated. Various mathematical models of in vivo transport and binding are discussed; most of these involve partitioning as the primary mechanism of transport. The models describe observed quantitative structure-activity relationships (QSARs) well on the whole, confirming that partitioning is of key importance in in vivo behavior of a xenobiotic. The partition coefficient is shown to correlate with numerous other parameters representing bulk, such as molecular weight, volume and surface area, parachor and calculated indices such as molecular connectivity; this is especially so for apolar molecules, because for polar molecules lipophilicity factors into both bulk and polar or hydrogen bonding components. The relationship of partition coefficient to chromatographic parameters is discussed, and it is shown that such parameters, which are often readily obtainable experimentally, can successfully supplant partition coefficient in QSARs. The relationship of aqueous solubility with partition coefficient is examined in detail. Correlations are observed, even with solid compounds, and these can be used to predict solubility. The additive/constitutive nature of partition coefficient is discussed extensively, as are the available schemes for the calculation of partition coefficient. Finally the use of partition coefficient to provide structural information is considered. It is shown that partition coefficient can be a valuable structural tool, especially if the enthalpy and entropy of partitioning are available. PMID:3905374

Parametric models to relate spike train and LFP dynamics with neural information processing.

PubMed

Banerjee, Arpan; Dean, Heather L; Pesaran, Bijan

2012-01-01

Spike trains and local field potentials (LFPs) resulting from extracellular current flows provide a substrate for neural information processing. Understanding the neural code from simultaneous spike-field recordings and subsequent decoding of information processing events will have widespread applications. One way to demonstrate an understanding of the neural code, with particular advantages for the development of applications, is to formulate a parametric statistical model of neural activity and its covariates. Here, we propose a set of parametric spike-field models (unified models) that can be used with existing decoding algorithms to reveal the timing of task or stimulus specific processing. Our proposed unified modeling framework captures the effects of two important features of information processing: time-varying stimulus-driven inputs and ongoing background activity that occurs even in the absence of environmental inputs. We have applied this framework for decoding neural latencies in simulated and experimentally recorded spike-field sessions obtained from the lateral intraparietal area (LIP) of awake, behaving monkeys performing cued look-and-reach movements to spatial targets. Using both simulated and experimental data, we find that estimates of trial-by-trial parameters are not significantly affected by the presence of ongoing background activity. However, including background activity in the unified model improves goodness of fit for predicting individual spiking events. Uncovering the relationship between the model parameters and the timing of movements offers new ways to test hypotheses about the relationship between neural activity and behavior. We obtained significant spike-field onset time correlations from single trials using a previously published data set where significantly strong correlation was only obtained through trial averaging. We also found that unified models extracted a stronger relationship between neural response latency and trial-by-trial behavioral performance than existing models of neural information processing. Our results highlight the utility of the unified modeling framework for characterizing spike-LFP recordings obtained during behavioral performance.

Does Sedentary Behavior Predict Academic Performance in Adolescents or the Other Way Round? A Longitudinal Path Analysis

PubMed Central

Lizandra, Jorge; Devís-Devís, José; Pérez-Gimeno, Esther; Valencia-Peris, Alexandra; Peiró-Velert, Carmen

2016-01-01

This study examined whether adolescents’ time spent on sedentary behaviors (academic, technological-based and social-based activities) was a better predictor of academic performance than the reverse. A cohort of 755 adolescents participated in a three-year period study. Structural Equation Modeling techniques were used to test plausible causal hypotheses. Four competing models were analyzed to determine which model best fitted the data. The Best Model was separately tested by gender. The Best Model showed that academic performance was a better predictor of sedentary behaviors than the other way round. It also indicated that students who obtained excellent academic results were more likely to succeed academically three years later. Moreover, adolescents who spent more time in the three different types of sedentary behaviors were more likely to engage longer in those sedentary behaviors after the three-year period. The better the adolescents performed academically, the less time they devoted to social-based activities and more to academic activities. An inverse relationship emerged between time dedicated to technological-based activities and academic sedentary activities. A moderating auto-regressive effect by gender indicated that boys were more likely to spend more time on technological-based activities three years later than girls. To conclude, previous academic performance predicts better sedentary behaviors three years later than the reverse. The positive longitudinal auto-regressive effects on the four variables under study reinforce the ‘success breeds success’ hypothesis, with academic performance and social-based activities emerging as the strongest ones. Technological-based activities showed a moderating effect by gender and a negative longitudinal association with academic activities that supports a displacement hypothesis. Other longitudinal and covariate effects reflect the complex relationships among sedentary behaviors and academic performance and the need to explore these relationships in depth. Theoretical and practical implications for school health are outlined. PMID:27055121

Does Sedentary Behavior Predict Academic Performance in Adolescents or the Other Way Round? A Longitudinal Path Analysis.

PubMed

Lizandra, Jorge; Devís-Devís, José; Pérez-Gimeno, Esther; Valencia-Peris, Alexandra; Peiró-Velert, Carmen

2016-01-01

This study examined whether adolescents' time spent on sedentary behaviors (academic, technological-based and social-based activities) was a better predictor of academic performance than the reverse. A cohort of 755 adolescents participated in a three-year period study. Structural Equation Modeling techniques were used to test plausible causal hypotheses. Four competing models were analyzed to determine which model best fitted the data. The Best Model was separately tested by gender. The Best Model showed that academic performance was a better predictor of sedentary behaviors than the other way round. It also indicated that students who obtained excellent academic results were more likely to succeed academically three years later. Moreover, adolescents who spent more time in the three different types of sedentary behaviors were more likely to engage longer in those sedentary behaviors after the three-year period. The better the adolescents performed academically, the less time they devoted to social-based activities and more to academic activities. An inverse relationship emerged between time dedicated to technological-based activities and academic sedentary activities. A moderating auto-regressive effect by gender indicated that boys were more likely to spend more time on technological-based activities three years later than girls. To conclude, previous academic performance predicts better sedentary behaviors three years later than the reverse. The positive longitudinal auto-regressive effects on the four variables under study reinforce the 'success breeds success' hypothesis, with academic performance and social-based activities emerging as the strongest ones. Technological-based activities showed a moderating effect by gender and a negative longitudinal association with academic activities that supports a displacement hypothesis. Other longitudinal and covariate effects reflect the complex relationships among sedentary behaviors and academic performance and the need to explore these relationships in depth. Theoretical and practical implications for school health are outlined.

Mathematical modeling of tetrahydroimidazole benzodiazepine-1-one derivatives as an anti HIV agent

NASA Astrophysics Data System (ADS)

Ojha, Lokendra Kumar

2017-07-01

The goal of the present work is the study of drug receptor interaction via QSAR (Quantitative Structure-Activity Relationship) analysis for 89 set of TIBO (Tetrahydroimidazole Benzodiazepine-1-one) derivatives. MLR (Multiple Linear Regression) method is utilized to generate predictive models of quantitative structure-activity relationships between a set of molecular descriptors and biological activity (IC50). The best QSAR model was selected having a correlation coefficient (r) of 0.9299 and Standard Error of Estimation (SEE) of 0.5022, Fisher Ratio (F) of 159.822 and Quality factor (Q) of 1.852. This model is statistically significant and strongly favours the substitution of sulphur atom, IS i.e. indicator parameter for -Z position of the TIBO derivatives. Two other parameter logP (octanol-water partition coefficient) and SAG (Surface Area Grid) also played a vital role in the generation of best QSAR model. All three descriptor shows very good stability towards data variation in leave-one-out (LOO).

Mapping recent chikungunya activity in the Americas

USDA-ARS?s Scientific Manuscript database

To better understand chikungunya activity in the America we mapped recent chikungunya activity in the Americas. This activity is needed to better understand that the relationships between climatic factors and disease outbreak patters are critical to the design and constructing of predictive models....

Molecular surface area based predictive models for the adsorption and diffusion of disperse dyes in polylactic acid matrix.

PubMed

Xu, Suxin; Chen, Jiangang; Wang, Bijia; Yang, Yiqi

2015-11-15

Two predictive models were presented for the adsorption affinities and diffusion coefficients of disperse dyes in polylactic acid matrix. Quantitative structure-sorption behavior relationship would not only provide insights into sorption process, but also enable rational engineering for desired properties. The thermodynamic and kinetic parameters for three disperse dyes were measured. The predictive model for adsorption affinity was based on two linear relationships derived by interpreting the experimental measurements with molecular structural parameters and compensation effect: ΔH° vs. dye size and ΔS° vs. ΔH°. Similarly, the predictive model for diffusion coefficient was based on two derived linear relationships: activation energy of diffusion vs. dye size and logarithm of pre-exponential factor vs. activation energy of diffusion. The only required parameters for both models are temperature and solvent accessible surface area of the dye molecule. These two predictive models were validated by testing the adsorption and diffusion properties of new disperse dyes. The models offer fairly good predictive ability. The linkage between structural parameter of disperse dyes and sorption behaviors might be generalized and extended to other similar polymer-penetrant systems. Copyright © 2015 Elsevier Inc. All rights reserved.

PLS-based quantitative structure-activity relationship for substituted benzamides of clebopride type. Application of experimental design in drug design.

PubMed

Norinder, U; Högberg, T

1992-04-01

The advantageous approach of using an experimentally designed training set as the basis for establishing a quantitative structure-activity relationship with good predictive capability is described. The training set was selected from a fractional factorial design scheme based on a principal component description of physico-chemical parameters of aromatic substituents. The derived model successfully predicts the activities of additional substituted benzamides of 6-methoxy-N-(4-piperidyl)salicylamide type. The major influence on activity of the 3-substituent is demonstrated.

Discovery of imidazo[1,2-b]pyridazine derivatives as IKKbeta inhibitors. Part 1: Hit-to-lead study and structure-activity relationship.

PubMed

Shimizu, Hiroki; Tanaka, Shinji; Toki, Tadashi; Yasumatsu, Isao; Akimoto, Toshihiko; Morishita, Kaoru; Yamasaki, Tomonori; Yasukochi, Takanori; Iimura, Shin

2010-09-01

Imidazo[1,2-b]pyridazine derivatives from high-throughput screening were developed as IKKbeta inhibitors. By the optimization of the 3- and 6-position of imidazo[1,2-b]pyridazine scaffold, cell-free IKKbeta inhibitory activity and TNFalpha inhibitory activity in THP-1 cell increased. Also, these compounds showed high kinase selectivity. The structure-activity relationship was revealed and the interaction model of imidazo[1,2-b]pyridazine compounds with IKKbeta was constructed. Copyright 2010. Published by Elsevier Ltd.

Chinese College Students' Physical Activity Correlates and Behavior: A Transtheoretical Model Perspective

ERIC Educational Resources Information Center

Xiong, Shanying; Li, Xianxiong; Tao, Kun; Zeng, Nan; Ayyub, Mohammad; Peng, Qingwen; Yan, Xiaoni; Wang, Junli; Wu, Yizhong; Lei, Mingzhi

2017-01-01

Guided by the Transtheoretical Model (Prochaska & DiClemente, 1982), this study investigated the differences of physical activity levels and correlates (i.e., self-efficacy, decisional balance, process of change) across different stages of change levels among Chinese college students. The relationships between students' physical activity…

Three-dimensional quantitative structure-activity relationship studies on c-Src inhibitors based on different docking methods.

PubMed

Bairy, Santhosh Kumar; Suneel Kumar, B V S; Bhalla, Joseph Uday Tej; Pramod, A B; Ravikumar, Muttineni

2009-04-01

c-Src kinase play an important role in cell growth and differentiation and its inhibitors can be useful for the treatment of various diseases, including cancer, osteoporosis, and metastatic bone disease. Three dimensional quantitative structure-activity relationship (3D-QSAR) studies were carried out on quinazolin derivatives inhibiting c-Src kinase. Molecular field analysis (MFA) models with four different alignment techniques, namely, GLIDE, GOLD, LIGANDFIT and Least squares based methods were developed. glide based MFA model showed better results (Leave one out cross validation correlation coefficient r(2)(cv) = 0.923 and non-cross validation correlation coefficient r(2)= 0.958) when compared with other models. These results help us to understand the nature of descriptors required for activity of these compounds and thereby provide guidelines to design novel and potent c-Src kinase inhibitors.

Passion for an activity and quality of interpersonal relationships: the mediating role of emotions.

PubMed

Philippe, Frederick L; Vallerand, Robert J; Houlfort, Nathalie; Lavigne, Geneviève L; Donahue, Eric G

2010-06-01

Our purpose in this research was to investigate the role of passion (Vallerand et al., 2003) for a given activity in the quality of interpersonal relationships experienced within the context of that activity in 4 studies. Study 1 demonstrated that a harmonious passion was positively associated with the quality of interpersonal relationships within the context of the passionate activity, whereas an obsessive passion was unrelated to it. Furthermore, in line with the broaden-and-build theory (Fredrickson, 2001), results also showed that positive emotions experienced at work fully mediated the relation between harmonious passion and quality of interpersonal relationships. Obsessive passion was not associated with positive emotions. Study 2 replicated the results from Study 1 while controlling for trait extraversion. Also, in Study 2, we examined the negative mediating role of negative emotions between obsessive passion and quality of interpersonal relationships. Finally, Studies 3 and 4 replicated the results of Study 2 with prospective designs and with objective ratings of interpersonal relationships quality. Implications for the dualistic model of passion and the broaden-and-build theory are discussed. (c) 2010 APA, all rights reserved).

Projecting climate-driven increases in North American fire activity

NASA Astrophysics Data System (ADS)

Wang, D.; Morton, D. C.; Collatz, G. J.

2013-12-01

Climate regulates fire activity through controls on vegetation productivity (fuels), lightning ignitions, and conditions governing fire spread. In many regions of the world, human management also influences the timing, duration, and extent of fire activity. These coupled interactions between human and natural systems make fire a complex component of the Earth system. Satellite data provide valuable information on the spatial and temporal dynamics of recent fire activity, as active fires, burned area, and land cover information can be combined to separate wildfires from intentional burning for agriculture and forestry. Here, we combined satellite-derived burned area data with land cover and climate data to assess fire-climate relationships in North America between 2000-2012. We used the latest versions of the Global Fire Emissions Database (GFED) burned area product and Modern-Era Retrospective Analysis for Research and Applications (MERRA) climate data to develop regional relationships between burned area and potential evaporation (PE), an integrated dryness metric. Logistic regression models were developed to link burned area with PE and individual climate variables during and preceding the fire season, and optimal models were selected based on Akaike Information Criterion (AIC). Overall, our model explained 85% of the variance in burned area since 2000 across North America. Fire-climate relationships from the era of satellite observations provide a blueprint for potential changes in fire activity under scenarios of climate change. We used that blueprint to evaluate potential changes in fire activity over the next 50 years based on twenty models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). All models suggest an increase of PE under low and high emissions scenarios (Representative Concentration Pathways (RCP) 4.5 and 8.5, respectively), with largest increases in projected burned area across the western US and central Canada. Overall, near-term climate projections point to pronounced changes in fire season length, total burned area, and the frequency of extreme events across North America by 2050.

Your Face is Your Fortune: Does Adolescent Attractiveness Predict Intimate Relationships Later in Life?

PubMed Central

Sicinski, Kamil; Moynihan, Donald

2017-01-01

Objective: A growing literature documents the importance of physical attractiveness in young and middle adulthood for romantic, marital, and sexual relationships, but little is known about how attractiveness in adolescence matters to intimate relationships in later life. We ask: does attractiveness early in life convey ongoing benefits late in life, or do such benefits erode over time? Methods: We use multivariate regression models and more than 50 years of data from the Wisconsin Longitudinal Study to examine the connections between adolescent physical attractiveness and intimate relationships (i.e., sexual activity and access to potential sexual partners) in later life. Results: We find that adolescent attractiveness facilitates sexual activity in later life. This relationship is largely driven by attractiveness increasing the probability of having access to potential sexual partners. However, attractiveness is not related to sexual activity among married couples, even after controlling for marital duration. Men, those in good health, and wealthier individuals are also more likely to engage in several facets of intimate relationships. Discussion: These findings highlight the importance of relationship context for later life sexual activity and begin to explicate the pathways through which factors across the life course—particularly attractiveness—influence sexual activity in later life. PMID:26655646

[Physical activity, obesity and self-esteem in chilean schoolchildren].

PubMed

Zurita-Ortega, Félix; Castro-Sánchez, Manuel; Rodríguez-Fernández, Sonia; Cofré-Boladós, Cristian; Chacón-Cuberos, Ramón; Martínez-Martínez, Asunción; Muros-Molina, José Joaquín

2017-03-01

Obesity is a worldwide epidemic disease and a problem for the Chilean society. To analyze the relationship between physical condition, body mass index (BMI), level of physical activity and self-esteem. Material ad Methods: Questionnaires to assess self-esteem (Rosemberg scale) and levels of physical activity (Physical Activity Questionnaire for older Children, PAQ-C) were answered by 515 children aged 10.5 ± 0.5 years from 27 schools of Santiago de Chile. BMI was calculated. Course-Navette test was carried out, vertical jump and hand dynamometry were measured. For statistical analysis, structural equations were used. An acceptable goodness of fit for the models was found. There was a positive relationship between BMI and hand dynamometry, as well as a negative relationship between BMI and maximal oxygen consumption, jumping ability, physical activity and self-esteem. Finally, self-esteem was positively related to physical activity engagement. In these children, self-esteem was related to physical activity variables.

Dimensional Model for Estimating Factors influencing Childhood Obesity: Path Analysis Based Modeling

PubMed Central

Kheirollahpour, Maryam; Shohaimi, Shamarina

2014-01-01

The main objective of this study is to identify and develop a comprehensive model which estimates and evaluates the overall relations among the factors that lead to weight gain in children by using structural equation modeling. The proposed models in this study explore the connection among the socioeconomic status of the family, parental feeding practice, and physical activity. Six structural models were tested to identify the direct and indirect relationship between the socioeconomic status and parental feeding practice general level of physical activity, and weight status of children. Finally, a comprehensive model was devised to show how these factors relate to each other as well as to the body mass index (BMI) of the children simultaneously. Concerning the methodology of the current study, confirmatory factor analysis (CFA) was applied to reveal the hidden (secondary) effect of socioeconomic factors on feeding practice and ultimately on the weight status of the children and also to determine the degree of model fit. The comprehensive structural model tested in this study suggested that there are significant direct and indirect relationships among variables of interest. Moreover, the results suggest that parental feeding practice and physical activity are mediators in the structural model. PMID:25097878

Relationship between the Macroscopic and Quantum Characteristics of Dynamic Viscosity for Hydrocarbons upon the Compensation Effect

NASA Astrophysics Data System (ADS)

Dolomatov, M. Yu.; Kovaleva, E. A.; Khamidullina, D. A.

2018-05-01

An approach that allows the calculation of dynamic viscosity for liquid hydrocarbons from quantum (ionization energies) and molecular (Wiener topological indices) parameters is proposed. A physical relationship is revealed between ionization and the energies of viscous flow activation. This relationship is due to the contribution from the dispersion component of Van der Waals forces to intermolecular interaction. A two-parameter dependence of the energy of viscous flow activation, energy of ionization, and Wiener topological indices is obtained. The dynamic viscosities of liquid hydrocarbons can be calculated from the kinetic compensation effect of dynamic viscosity, which indicates a relationship between the energy of activation and the Arrhenius pre-exponental factor of the Frenkel-Eyring hole model. Calculation results are confirmed through statistical processing of the experimental data.

Discovery and structure-activity relationships of a series of pyroglutamic acid amide antagonists of the P2X7 receptor.

PubMed

Abdi, Muna H; Beswick, Paul J; Billinton, Andy; Chambers, Laura J; Charlton, Andrew; Collins, Sue D; Collis, Katharine L; Dean, David K; Fonfria, Elena; Gleave, Robert J; Lejeune, Clarisse L; Livermore, David G; Medhurst, Stephen J; Michel, Anton D; Moses, Andrew P; Page, Lee; Patel, Sadhana; Roman, Shilina A; Senger, Stefan; Slingsby, Brian; Steadman, Jon G A; Stevens, Alexander J; Walter, Daryl S

2010-09-01

A computational lead-hopping exercise identified compound 4 as a structurally distinct P2X(7) receptor antagonist. Structure-activity relationships (SAR) of a series of pyroglutamic acid amide analogues of 4 were investigated and compound 31 was identified as a potent P2X(7) antagonist with excellent in vivo activity in animal models of pain, and a profile suitable for progression to clinical studies. Copyright 2010 Elsevier Ltd. All rights reserved.

The Health Action Process Approach as a motivational model for physical activity self-management for people with multiple sclerosis: a path analysis.

PubMed

Chiu, Chung-Yi; Lynch, Ruth T; Chan, Fong; Berven, Norman L

2011-08-01

To evaluate the Health Action Process Approach (HAPA) as a motivational model for physical activity self-management for people with multiple sclerosis (MS). Quantitative descriptive research design using path analysis. One hundred ninety-five individuals with MS were recruited from the National Multiple Sclerosis Society and a neurology clinic at a university teaching hospital in the Midwest. Outcome was measured by the Physical Activity Stages of Change Instrument, along with measures for nine predictors (severity, action self-efficacy, outcome expectancy, risk perception, perceived barriers, intention, maintenance self-efficacy, action and coping planning, and recovery self-efficacy). The respecified HAPA physical activity model fit the data relatively well (goodness-of-fit index = .92, normed fit index = .91, and comparative fit index = .93) explaining 38% of the variance in physical activity. Recovery self-efficacy, action and coping planning, and perceived barriers directly contributed to the prediction of physical activity. Outcome expectancy significantly influenced intention and the relationship between intention and physical activity is mediated by action and coping planning. Action self-efficacy, maintenance self-efficacy, and recovery self-efficacy directly or indirectly affected physical activity. Severity of MS and action self-efficacy had an inverse relationship with perceived barriers and perceived barriers influenced physical activity. Empirical support was found for the proposed HAPA model of physical activity for people with MS. The HAPA model appears to provide useful information for clinical rehabilitation and health promotion interventions.

Perceived sports competence mediates the relationship between childhood motor skill proficiency and adolescent physical activity and fitness: a longitudinal assessment.

PubMed

Barnett, Lisa M; Morgan, Philip J; van Beurden, Eric; Beard, John R

2008-08-08

The purpose of this paper was to investigate whether perceived sports competence mediates the relationship between childhood motor skill proficiency and subsequent adolescent physical activity and fitness. In 2000, children's motor skill proficiency was assessed as part of a school-based physical activity intervention. In 2006/07, participants were followed up as part of the Physical Activity and Skills Study and completed assessments for perceived sports competence (Physical Self-Perception Profile), physical activity (Adolescent Physical Activity Recall Questionnaire) and cardiorespiratory fitness (Multistage Fitness Test). Structural equation modelling techniques were used to determine whether perceived sports competence mediated between childhood object control skill proficiency (composite score of kick, catch and overhand throw), and subsequent adolescent self-reported time in moderate-to-vigorous physical activity and cardiorespiratory fitness. Of 928 original intervention participants, 481 were located in 28 schools and 276 (57%) were assessed with at least one follow-up measure. Slightly more than half were female (52.4%) with a mean age of 16.4 years (range 14.2 to 18.3 yrs). Relevant assessments were completed by 250 (90.6%) students for the Physical Activity Model and 227 (82.3%) for the Fitness Model. Both hypothesised mediation models had a good fit to the observed data, with the Physical Activity Model accounting for 18% (R2 = 0.18) of physical activity variance and the Fitness Model accounting for 30% (R2 = 0.30) of fitness variance. Sex did not act as a moderator in either model. Developing a high perceived sports competence through object control skill development in childhood is important for both boys and girls in determining adolescent physical activity participation and fitness. Our findings highlight the need for interventions to target and improve the perceived sports competence of youth.

Motor Competence and its Effect on Positive Developmental Trajectories of Health.

PubMed

Robinson, Leah E; Stodden, David F; Barnett, Lisa M; Lopes, Vitor P; Logan, Samuel W; Rodrigues, Luis Paulo; D'Hondt, Eva

2015-09-01

In 2008, Stodden and colleagues took a unique developmental approach toward addressing the potential role of motor competence in promoting positive or negative trajectories of physical activity, health-related fitness, and weight status. The conceptual model proposed synergistic relationships among physical activity, motor competence, perceived motor competence, health-related physical fitness, and obesity with associations hypothesized to strengthen over time. At the time the model was proposed, limited evidence was available to support or refute the model hypotheses. Over the past 6 years, the number of investigations exploring these relationships has increased significantly. Thus, it is an appropriate time to examine published data that directly or indirectly relate to specific pathways noted in the conceptual model. Evidence indicates that motor competence is positively associated with perceived competence and multiple aspects of health (i.e., physical activity, cardiorespiratory fitness, muscular strength, muscular endurance, and a healthy weight status). However, questions related to the increased strength of associations across time and antecedent/consequent mechanisms remain. An individual's physical and psychological development is a complex and multifaceted process that synergistically evolves across time. Understanding the most salient factors that influence health and well-being and how relationships among these factors change across time is a critical need for future research in this area. This knowledge could aid in addressing the declining levels of physical activity and fitness along with the increasing rates of obesity across childhood and adolescence.

Predicting adsorption isotherms for aqueous organic micropollutants from activated carbon and pollutant properties.

PubMed

Li, Lei; Quinlivan, Patricia A; Knappe, Detlef R U

2005-05-01

A method based on the Polanyi-Dubinin-Manes (PDM) model is presented to predict adsorption isotherms of aqueous organic contaminants on activated carbons. It was assumed that trace organic compound adsorption from aqueous solution is primarily controlled by nonspecific dispersive interactions while water adsorption is controlled by specific interactions with oxygen-containing functional groups on the activated carbon surface. Coefficients describing the affinity of water for the activated carbon surface were derived from aqueous-phase methyl tertiary-butyl ether (MTBE) and trichloroethene (TCE) adsorption isotherm data that were collected with 12 well-characterized activated carbons. Over the range of oxygen contents covered by the adsorbents (approximately 0.8-10 mmol O/g dry, ash-free activated carbon), a linear relationship between water affinity coefficients and adsorbent oxygen content was obtained. Incorporating water affinity coefficients calculated from the developed relationship into the PDM model, isotherm predictions resulted that agreed well with experimental data for three adsorbents and two adsorbates [tetrachloroethene (PCE), cis-1,2-dichloroethene (DCE)] that were not used to calibrate the model.

Quantitative Structure-Activity Relationship Modeling Coupled with Molecular Docking Analysis in Screening of Angiotensin I-Converting Enzyme Inhibitory Peptides from Qula Casein Hydrolysates Obtained by Two-Enzyme Combination Hydrolysis.

PubMed

Lin, Kai; Zhang, Lanwei; Han, Xue; Meng, Zhaoxu; Zhang, Jianming; Wu, Yifan; Cheng, Dayou

2018-03-28

In this study, Qula casein derived from yak milk casein was hydrolyzed using a two-enzyme combination approach, and high angiotensin I-converting enzyme (ACE) inhibitory activity peptides were screened by quantitative structure-activity relationship (QSAR) modeling integrated with molecular docking analysis. Hydrolysates (<3 kDa) derived from combinations of thermolysin + alcalase and thermolysin + proteinase K demonstrated high ACE inhibitory activities. Peptide sequences in hydrolysates derived from these two combinations were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). On the basis of the QSAR modeling prediction, a total of 16 peptides were selected for molecular docking analysis. The docking study revealed that four of the peptides (KFPQY, MPFPKYP, MFPPQ, and QWQVL) bound the active site of ACE. These four novel peptides were chemically synthesized, and their IC 50 was determined. Among these peptides, KFPQY showed the highest ACE inhibitory activity (IC 50 = 12.37 ± 0.43 μM). Our study indicated that Qula casein presents an excellent source to produce ACE inhibitory peptides.

A review of the global relationship among freshwater fish, autotrophic activity, and regional climate

USGS Publications Warehouse

Deines, Andrew M.; Bunnell, David B.; Rogers, Mark W.; Beard, T. Douglas; Taylor, William W.

2015-01-01

The relationship between autotrophic activity and freshwater fish populations is an important consideration for ecologists describing trophic structure in aquatic communities, fisheries managers tasked with increasing sustainable fisheries development, and fish farmers seeking to maximize production. Previous studies of the empirical relationships of autotrophic activity and freshwater fish yield have found positive relationships but were limited by small sample sizes, small geographic scopes, and the inability to compare patterns among many types of measurement techniques. Individual studies and reviews have also lacked consistent consideration of regional climate factors which may inform relationships between fisheries and autotrophic activity. We compiled data from over 700 freshwater systems worldwide and used meta-analysis and linear models to develop a comprehensive global synthesis between multiple metrics of autotrophic activity, fisheries, and climate indicators. Our results demonstrate that multiple metrics of fish (i.e., catch per unit effort, yield, and production) increase with autotrophic activity across a variety of fisheries. At the global scale additional variation in this positive relationship can be ascribed to regional climate differences (i.e., temperature and precipitation) across systems. Our results provide a method and proof-of-concept for assessing inland fisheries production at the global scale, where current estimates are highly uncertain, and may therefore inform the continued sustainable use of global inland fishery resources.

Spatial and temporal distribution of chikungunya activity in the Americas

USDA-ARS?s Scientific Manuscript database

To better understand chikungunya activity in the America we mapped recent chikungunya activity in the Americas. This activity is needed to better understand that the relationships between climatic factors and disease outbreak patters are critical to the design and constructing of predictive models....

Neuroimaging explanations of age-related differences in task performance.

PubMed

Steffener, Jason; Barulli, Daniel; Habeck, Christian; Stern, Yaakov

2014-01-01

Advancing age affects both cognitive performance and functional brain activity and interpretation of these effects has led to a variety of conceptual research models without always explicitly linking the two effects. However, to best understand the multifaceted effects of advancing age, age differences in functional brain activity need to be explicitly tied to the cognitive task performance. This work hypothesized that age-related differences in task performance are partially explained by age-related differences in functional brain activity and formally tested these causal relationships. Functional MRI data was from groups of young and old adults engaged in an executive task-switching experiment. Analyses were voxel-wise testing of moderated-mediation and simple mediation statistical path models to determine whether age group, brain activity and their interaction explained task performance in regions demonstrating an effect of age group. Results identified brain regions whose age-related differences in functional brain activity significantly explained age-related differences in task performance. In all identified locations, significant moderated-mediation relationships resulted from increasing brain activity predicting worse (slower) task performance in older but not younger adults. Findings suggest that advancing age links task performance to the level of brain activity. The overall message of this work is that in order to understand the role of functional brain activity on cognitive performance, analysis methods should respect theoretical relationships. Namely, that age affects brain activity and brain activity is related to task performance.

Combinatorial QSAR Modeling of Rat Acute Toxicity by Oral Exposure

EPA Science Inventory

Quantitative Structure-Activity Relationship (QSAR) toxicity models have become popular tools for identifying potential toxic compounds and prioritizing candidates for animal toxicity tests. However, few QSAR studies have successfully modeled large, diverse mammalian toxicity end...

Origin and Consequences of the Relationship between Protein Mean and Variance

PubMed Central

Vallania, Francesco Luigi Massimo; Sherman, Marc; Goodwin, Zane; Mogno, Ilaria; Cohen, Barak Alon; Mitra, Robi David

2014-01-01

Cell-to-cell variance in protein levels (noise) is a ubiquitous phenomenon that can increase fitness by generating phenotypic differences within clonal populations of cells. An important challenge is to identify the specific molecular events that control noise. This task is complicated by the strong dependence of a protein's cell-to-cell variance on its mean expression level through a power-law like relationship (σ2∝μ1.69). Here, we dissect the nature of this relationship using a stochastic model parameterized with experimentally measured values. This framework naturally recapitulates the power-law like relationship (σ2∝μ1.6) and accurately predicts protein variance across the yeast proteome (r2 = 0.935). Using this model we identified two distinct mechanisms by which protein variance can be increased. Variables that affect promoter activation, such as nucleosome positioning, increase protein variance by changing the exponent of the power-law relationship. In contrast, variables that affect processes downstream of promoter activation, such as mRNA and protein synthesis, increase protein variance in a mean-dependent manner following the power-law. We verified our findings experimentally using an inducible gene expression system in yeast. We conclude that the power-law-like relationship between noise and protein mean is due to the kinetics of promoter activation. Our results provide a framework for understanding how molecular processes shape stochastic variation across the genome. PMID:25062021

Retro-binding thrombin active site inhibitors: identification of an orally active inhibitor of thrombin catalytic activity.

PubMed

Iwanowicz, Edwin J; Kimball, S David; Lin, James; Lau, Wan; Han, W-C; Wang, Tammy C; Roberts, Daniel G M; Schumacher, W A; Ogletree, Martin L; Seiler, Steven M

2002-11-04

A series of retro-binding inhibitors of human alpha-thrombin was prepared to elucidate structure-activity relationships (SAR) and optimize in vivo performance. Compounds 9 and 11, orally active inhibitors of thrombin catalytic activity, were identified to be efficacious in a thrombin-induced lethality model in mice.

Further evaluation of quantitative structure--activity relationship models for the prediction of the skin sensitization potency of selected fragrance allergens.

PubMed

Patlewicz, Grace Y; Basketter, David A; Pease, Camilla K Smith; Wilson, Karen; Wright, Zoe M; Roberts, David W; Bernard, Guillaume; Arnau, Elena Giménez; Lepoittevin, Jean-Pierre

2004-02-01

Fragrance substances represent a very diverse group of chemicals; a proportion of them are associated with the ability to cause allergic reactions in the skin. Efforts to find substitute materials are hindered by the need to undertake animal testing for determining both skin sensitization hazard and potency. One strategy to avoid such testing is through an understanding of the relationships between chemical structure and skin sensitization, so-called structure-activity relationships. In recent work, we evaluated 2 groups of fragrance chemicals -- saturated aldehydes and alpha,beta-unsaturated aldehydes. Simple quantitative structure-activity relationship (QSAR) models relating the EC3 values [derived from the local lymph node assay (LLNA)] to physicochemical properties were developed for both sets of aldehydes. In the current study, we evaluated an additional group of carbonyl-containing compounds to test the predictive power of the developed QSARs and to extend their scope. The QSAR models were used to predict EC3 values of 10 newly selected compounds. Local lymph node assay data generated for these compounds demonstrated that the original QSARs were fairly accurate, but still required improvement. Development of these QSAR models has provided us with a better understanding of the potential mechanisms of action for aldehydes, and hence how to avoid or limit allergy. Knowledge generated from this work is being incorporated into new/improved rules for sensitization in the expert toxicity prediction system, deductive estimation of risk from existing knowledge (DEREK).

Physical activity and quality of life in older adults: an 18-month panel analysis.

PubMed

Phillips, Siobhan M; Wójcicki, Thomas R; McAuley, Edward

2013-09-01

Although physical activity has been associated with quality of life (QOL), the empirical evidence regarding the mechanisms underlying this relationship is limited. In the present study, we examined the mediating roles played by self-efficacy and health status in the physical activity-QOL relationship from baseline to 18-month follow-up in a sample of community-dwelling older adults. Community-dwelling adults (N = 321, M age = 63.8 years) were recruited to participate in a cross-sectional study and were later contacted to participate in an 18-month follow-up. Individuals completed a battery of questionnaires assessing physical activity, self-efficacy, physical self-worth, disability limitations, and quality of life. A panel analysis within a covariance modeling framework was used to analyze the data. Overall, the model was a good fit to the data (χ(2) = 61.00, df = 29, p < 0.001, standardized root mean residual = 0.05, Comparative Fit Index = 0.97) with changes in physical activity indirectly influencing change in life satisfaction from baseline to 18 months via changes in exercise self-efficacy, physical self-worth, and disability limitations independent of baseline relationships and demographic factors. Specifically, increases in physical activity were associated with increases in exercise self-efficacy which, in turn, was associated with higher physical self-worth and fewer disability limitations which were associated with greater life satisfaction. The findings from this study suggest the relationship between physical activity and global QOL in older adults may be mediated by more proximal modifiable outcomes that can be targeted in physical activity programs and interventions.

Mothers' Perspectives on the Development of Their Preschoolers' Dietary and Physical Activity Behaviors and Parent-Child Relationship: Implications for Pediatric Primary Care Physicians.

PubMed

Pratt, Keeley J; Van Fossen, Catherine; Cotto-Maisonet, Jennifer; Palmer, Elizabeth N; Eneli, Ihuoma

2017-07-01

The study explores female caregivers' reflections on their relationship with their child (2-5 years old) and the development of their child's dietary and physical activity behaviors. Five, 90-minute semistructured focus groups were conducted to inquire about children's growth, eating behaviors and routines, physical activity, personality, and the parent-child relationship. Nineteen female caregivers diverse in race/ethnicity, age, and educational attainment participated. Participants reported that they maintained a schedule, but needed to be flexible to accommodate daily responsibilities. Family, social factors, and day care routines were influences on their children's behaviors. The main physical activity barriers were safety and time constraints. Guidance from pediatric primary care providers aimed at supporting female caregivers to build a positive foundation in their parent-child relationship, and to adopt and model healthy diet and physical activity behaviors that are respectful of schedules and barriers should be a priority for childhood obesity prevention.

Physical activity, subjective sleep quality and time in bed do not vary by moon phase in German adolescents.

PubMed

Smith, Maia P; Standl, Marie; Schulz, Holger; Heinrich, Joachim

2017-06-01

Lunar periodicity in human biology and behaviour, particularly sleep, has been reported. However, estimated relationships vary in direction (more or less sleep with full moon) if they exist at all, and studies tend to be so small that there is potential for confounding by weekly or monthly cycles. Lunar variation in physical activity has been posited as a driver of this relationship, but is likewise not well studied. We explore the association between lunar cycle, sleep and physical activity in a population-based sample of 1411 Germans age 14-17 years (46% male). Physical activity (daily minutes moderate-to-vigorous activity) was objectively assessed by accelerometry for a total of 8832 days between 2011 and 2014. At the same time, time in bed (h) and subjective sleep quality (1-6) were diaried each morning. In models corrected for confounding, we found that lunar phase was not significantly associated with physical activity, subjective sleep quality or time in bed in either sex, regardless of season. Observed relationships varied randomly in direction between models, suggesting artefact. Thus, this large, objectively-measured and well-controlled population of adolescents displayed no lunar periodicity in objective physical activity, subjective sleep quality or time in bed. © 2016 European Sleep Research Society.

2D-QSAR and 3D-QSAR Analyses for EGFR Inhibitors

PubMed Central

Zhao, Manman; Zheng, Linfeng; Qiu, Chun

2017-01-01

Epidermal growth factor receptor (EGFR) is an important target for cancer therapy. In this study, EGFR inhibitors were investigated to build a two-dimensional quantitative structure-activity relationship (2D-QSAR) model and a three-dimensional quantitative structure-activity relationship (3D-QSAR) model. In the 2D-QSAR model, the support vector machine (SVM) classifier combined with the feature selection method was applied to predict whether a compound was an EGFR inhibitor. As a result, the prediction accuracy of the 2D-QSAR model was 98.99% by using tenfold cross-validation test and 97.67% by using independent set test. Then, in the 3D-QSAR model, the model with q2 = 0.565 (cross-validated correlation coefficient) and r2 = 0.888 (non-cross-validated correlation coefficient) was built to predict the activity of EGFR inhibitors. The mean absolute error (MAE) of the training set and test set was 0.308 log units and 0.526 log units, respectively. In addition, molecular docking was also employed to investigate the interaction between EGFR inhibitors and EGFR. PMID:28630865

A measurement error model for physical activity level as measured by a questionnaire with application to the 1999-2006 NHANES questionnaire.

PubMed

Tooze, Janet A; Troiano, Richard P; Carroll, Raymond J; Moshfegh, Alanna J; Freedman, Laurence S

2013-06-01

Systematic investigations into the structure of measurement error of physical activity questionnaires are lacking. We propose a measurement error model for a physical activity questionnaire that uses physical activity level (the ratio of total energy expenditure to basal energy expenditure) to relate questionnaire-based reports of physical activity level to true physical activity levels. The 1999-2006 National Health and Nutrition Examination Survey physical activity questionnaire was administered to 433 participants aged 40-69 years in the Observing Protein and Energy Nutrition (OPEN) Study (Maryland, 1999-2000). Valid estimates of participants' total energy expenditure were also available from doubly labeled water, and basal energy expenditure was estimated from an equation; the ratio of those measures estimated true physical activity level ("truth"). We present a measurement error model that accommodates the mixture of errors that arise from assuming a classical measurement error model for doubly labeled water and a Berkson error model for the equation used to estimate basal energy expenditure. The method was then applied to the OPEN Study. Correlations between the questionnaire-based physical activity level and truth were modest (r = 0.32-0.41); attenuation factors (0.43-0.73) indicate that the use of questionnaire-based physical activity level would lead to attenuated estimates of effect size. Results suggest that sample sizes for estimating relationships between physical activity level and disease should be inflated, and that regression calibration can be used to provide measurement error-adjusted estimates of relationships between physical activity and disease.

Combining molecular docking and QSAR studies for modeling the anti-tyrosinase activity of aromatic heterocycle thiosemicarbazone analogues

NASA Astrophysics Data System (ADS)

Dong, Huanhuan; Liu, Jing; Liu, Xiaoru; Yu, Yanying; Cao, Shuwen

2018-01-01

A collection of thirty-six aromatic heterocycle thiosemicarbazone analogues presented a broad span of anti-tyrosinase activities were designed and obtained. A robust and reliable two-dimensional quantitative structure-activity relationship model, as evidenced by the high q2 and r2 values (0.848 and 0.893, respectively), was gained based on the analogues to predict the quantitative chemical-biological relationship and the new modifier direction. Inhibitory activities of the compounds were found to greatly depend on molecular shape and orbital energy. Substituents brought out large ovality and high highest-occupied molecular orbital energy values helped to improve the activity of these analogues. The molecular docking results provided visual evidence for QSAR analysis and inhibition mechanism. Based on these, two novel tyrosinase inhibitors O04 and O05 with predicted IC50 of 0.5384 and 0.8752 nM were designed and suggested for further research.

Ice nucleation temperature influences recovery of activity of a model protein after freeze drying.

PubMed

Cochran, Teresa; Nail, Steven L

2009-09-01

The objective of this study was to determine whether a relationship exists between ice nucleation temperature and recovery of activity of a model protein, lactate dehydrogenase, after freeze drying. Aqueous buffer systems containing 50 microg/mL of protein were frozen in vials with externally mounted thermocouples on the shelf of a freeze dryer, then freeze dried. Various methods were used to establish a wide range of ice nucleation temperatures. An inverse relationship was found between the extent of supercooling during freezing and recovery of activity in the reconstituted solution. The data are consistent with a mechanism of inactivation resulting from adsorption of protein at the ice/freeze-concentrate interface during the freezing process.

Effect of inhibitory feedback on correlated firing of spiking neural network.

PubMed

Xie, Jinli; Wang, Zhijie

2013-08-01

Understanding the properties and mechanisms that generate different forms of correlation is critical for determining their role in cortical processing. Researches on retina, visual cortex, sensory cortex, and computational model have suggested that fast correlation with high temporal precision appears consistent with common input, and correlation on a slow time scale likely involves feedback. Based on feedback spiking neural network model, we investigate the role of inhibitory feedback in shaping correlations on a time scale of 100 ms. Notably, the relationship between the correlation coefficient and inhibitory feedback strength is non-monotonic. Further, computational simulations show how firing rate and oscillatory activity form the basis of the mechanisms underlying this relationship. When the mean firing rate holds unvaried, the correlation coefficient increases monotonically with inhibitory feedback, but the correlation coefficient keeps decreasing when the network has no oscillatory activity. Our findings reveal that two opposing effects of the inhibitory feedback on the firing activity of the network contribute to the non-monotonic relationship between the correlation coefficient and the strength of the inhibitory feedback. The inhibitory feedback affects the correlated firing activity by modulating the intensity and regularity of the spike trains. Finally, the non-monotonic relationship is replicated with varying transmission delay and different spatial network structure, demonstrating the universality of the results.

ABO/Rh Blood-Typing Model: A Problem-Solving Activity

ERIC Educational Resources Information Center

Wake, Carol

2005-01-01

An ARO/Rh Blood-Typing kit useful for students to visualize blood-typing activities and practice problem-solving skills with transfusion reactions is presented. The model also enables students to identify relationships between A, B, and Rh antigens and antibodies in blood and to understand molecular mechanisms involved in transfusion agglutination…

"JCE" Classroom Activity #109: My Acid Can Beat Up Your Acid!

ERIC Educational Resources Information Center

Putti, Alice

2011-01-01

In this guided-inquiry activity, students investigate the ionization of strong and weak acids. Bead models are used to study acid ionization on a particulate level. Students analyze seven strong and weak acid models and make generalizations about the relationship between acid strength and dissociation. (Contains 1 table and 2 figures.)

QUANTITATIVE STRUCTURE—PROPERTY RELATIONSHIPS FOR ENHANCING PREDICTIONS OF SYNTHETIC ORGANIC CHEMICAL REMOVAL FROM DRINKING WATER BY GRANULAR ACTIVATED CARBON

EPA Science Inventory

A number of mathematical models have been developed to predict activated carbon column performance using single-solute isotherm data as inputs. Many assumptions are built into these models to account for kinetics of adsorption and competition for adsorption sites. This work...

A new model to study sleep deprivation-induced seizure.

PubMed

Lucey, Brendan P; Leahy, Averi; Rosas, Regine; Shaw, Paul J

2015-05-01

A relationship between sleep and seizures is well-described in both humans and rodent animal models; however, the mechanism underlying this relationship is unknown. Using Drosophila melanogaster mutants with seizure phenotypes, we demonstrate that seizure activity can be modified by sleep deprivation. Seizure activity was evaluated in an adult bang-sensitive seizure mutant, stress sensitive B (sesB(9ed4)), and in an adult temperature sensitive seizure mutant seizure (sei(ts1)) under baseline and following 12 h of sleep deprivation. The long-term effect of sleep deprivation on young, immature sesB(9ed4) flies was also assessed. Laboratory. Drosophila melanogaster. Sleep deprivation. Sleep deprivation increased seizure susceptibility in adult sesB(9ed4)/+ and sei(ts1) mutant flies. Sleep deprivation also increased seizure susceptibility when sesB was disrupted using RNAi. The effect of sleep deprivation on seizure activity was reduced when sesB(9ed4)/+ flies were given the anti-seizure drug, valproic acid. In contrast to adult flies, sleep deprivation during early fly development resulted in chronic seizure susceptibility when sesB(9ed4)/+ became adults. These findings show that Drosophila is a model organism for investigating the relationship between sleep and seizure activity. © 2015 Associated Professional Sleep Societies, LLC.

2D- and 3D-quantitative structure-activity relationship studies for a series of phenazine N,N'-dioxide as antitumour agents.

PubMed

Cunha, Jonathan Da; Lavaggi, María Laura; Abasolo, María Inés; Cerecetto, Hugo; González, Mercedes

2011-12-01

Hypoxic regions of tumours are associated with increased resistance to radiation and chemotherapy. Nevertheless, hypoxia has been used as a tool for specific activation of some antitumour prodrugs, named bioreductive agents. Phenazine dioxides are an example of such bioreductive prodrugs. Our 2D-quantitative structure activity relationship studies established that phenazine dioxides electronic and lipophilic descriptors are related to survival fraction in oxia or in hypoxia. Additionally, statistically significant models, derived by partial least squares, were obtained between survival fraction in oxia and comparative molecular field analysis standard model (r² = 0.755, q² = 0.505 and F = 26.70) or comparative molecular similarity indices analysis-combined steric and electrostatic fields (r² = 0.757, q² = 0.527 and F = 14.93), and survival fraction in hypoxia and comparative molecular field analysis standard model (r² = 0.736, q² = 0.521 and F = 18.63) or comparative molecular similarity indices analysis-hydrogen bond acceptor field (r² = 0.858, q² = 0.737 and F = 27.19). Categorical classification was used for the biological parameter selective cytotoxicity emerging also good models, derived by soft independent modelling of class analogy, with both comparative molecular field analysis standard model (96% of overall classification accuracy) and comparative molecular similarity indices analysis-steric field (92% of overall classification accuracy). 2D- and 3D-quantitative structure-activity relationships models provided important insights into the chemical and structural basis involved in the molecular recognition process of these phenazines as bioreductive agents and should be useful for the design of new structurally related analogues with improved potency. © 2011 John Wiley & Sons A/S.

Building Relationship Communication Skills for Transformational Leadership.

ERIC Educational Resources Information Center

Raiola, Edward O.

1995-01-01

The most important skill for the transformational leader is building relationships through positive and effective communication. Provides guidelines for supporting and encouraging group members, setting the tone for the group, modeling communication behaviors, use of voice patterns, active listening, reflective communication (paraphrasing),…

Design and prediction of new anticoagulants as a selective Factor IXa inhibitor via three-dimensional quantitative structure-property relationships of amidinobenzothiophene derivatives.

PubMed

Gao, Jia-Suo; Tong, Xu-Peng; Chang, Yi-Qun; He, Yu-Xuan; Mei, Yu-Dan; Tan, Pei-Hong; Guo, Jia-Liang; Liao, Guo-Chao; Xiao, Gao-Keng; Chen, Wei-Min; Zhou, Shu-Feng; Sun, Ping-Hua

2015-01-01

Factor IXa (FIXa), a blood coagulation factor, is specifically inhibited at the initiation stage of the coagulation cascade, promising an excellent approach for developing selective and safe anticoagulants. Eighty-four amidinobenzothiophene antithrombotic derivatives targeting FIXa were selected to establish three-dimensional quantitative structure-activity relationship (3D-QSAR) and three-dimensional quantitative structure-selectivity relationship (3D-QSSR) models using comparative molecular field analysis and comparative similarity indices analysis methods. Internal and external cross-validation techniques were investigated as well as region focusing and bootstrapping. The satisfactory q (2) values of 0.753 and 0.770, and r (2) values of 0.940 and 0.965 for 3D-QSAR and 3D-QSSR, respectively, indicated that the models are available to predict both the inhibitory activity and selectivity on FIXa against Factor Xa, the activated status of Factor X. This work revealed that the steric, hydrophobic, and H-bond factors should appropriately be taken into account in future rational design, especially the modifications at the 2'-position of the benzene and the 6-position of the benzothiophene in the R group, providing helpful clues to design more active and selective FIXa inhibitors for the treatment of thrombosis. On the basis of the three-dimensional quantitative structure-property relationships, 16 new potent molecules have been designed and are predicted to be more active and selective than Compound 33, which has the best activity as reported in the literature.

Design and prediction of new anticoagulants as a selective Factor IXa inhibitor via three-dimensional quantitative structure-property relationships of amidinobenzothiophene derivatives

PubMed Central

Gao, Jia-Suo; Tong, Xu-Peng; Chang, Yi-Qun; He, Yu-Xuan; Mei, Yu-Dan; Tan, Pei-Hong; Guo, Jia-Liang; Liao, Guo-Chao; Xiao, Gao-Keng; Chen, Wei-Min; Zhou, Shu-Feng; Sun, Ping-Hua

2015-01-01

Factor IXa (FIXa), a blood coagulation factor, is specifically inhibited at the initiation stage of the coagulation cascade, promising an excellent approach for developing selective and safe anticoagulants. Eighty-four amidinobenzothiophene antithrombotic derivatives targeting FIXa were selected to establish three-dimensional quantitative structure–activity relationship (3D-QSAR) and three-dimensional quantitative structure–selectivity relationship (3D-QSSR) models using comparative molecular field analysis and comparative similarity indices analysis methods. Internal and external cross-validation techniques were investigated as well as region focusing and bootstrapping. The satisfactory q2 values of 0.753 and 0.770, and r2 values of 0.940 and 0.965 for 3D-QSAR and 3D-QSSR, respectively, indicated that the models are available to predict both the inhibitory activity and selectivity on FIXa against Factor Xa, the activated status of Factor X. This work revealed that the steric, hydrophobic, and H-bond factors should appropriately be taken into account in future rational design, especially the modifications at the 2′-position of the benzene and the 6-position of the benzothiophene in the R group, providing helpful clues to design more active and selective FIXa inhibitors for the treatment of thrombosis. On the basis of the three-dimensional quantitative structure–property relationships, 16 new potent molecules have been designed and are predicted to be more active and selective than Compound 33, which has the best activity as reported in the literature. PMID:25848211

Applications of genetic algorithms on the structure-activity relationship analysis of some cinnamamides.

PubMed

Hou, T J; Wang, J M; Liao, N; Xu, X J

1999-01-01

Quantitative structure-activity relationships (QSARs) for 35 cinnamamides were studied. By using a genetic algorithm (GA), a group of multiple regression models with high fitness scores was generated. From the statistical analyses of the descriptors used in the evolution procedure, the principal features affecting the anticonvulsant activity were found. The significant descriptors include the partition coefficient, the molar refraction, the Hammet sigma constant of the substituents on the benzene ring, and the formation energy of the molecules. It could be found that the steric complementarity and the hydrophobic interaction between the inhibitors and the receptor were very important to the biological activity, while the contribution of the electronic effect was not so obvious. Moreover, by construction of the spline models for these four principal descriptors, the effective range for each descriptor was identified.

Modeling the cross-sectional relationships between religion, physical health, social support, and depressive symptoms.

PubMed

Koenig, H G; Hays, J C; George, L K; Blazer, D G; Larson, D B; Landerman, L R

1997-01-01

The authors examined models of the relationships between religious activities, physical health, social support, and depressive symptoms in a sample of 4,000 persons age 65 and over. Religious activity was examined first as a single composite construct and then split into three component variables that were examined individually. Religious activity as a single construct was correlated with both social support and good physical health but was unrelated to depression. Split into the three components, model fit was significantly increased. Frequency of church attendance was positively related to physical health and negatively related to depression, but was surprisingly unrelated to social support. Frequent churchgoers were about half as likely to be depressed. Private prayer/Bible reading was negatively correlated with physical health and positively correlated with social support, but unrelated to depression. Religious TV/radio listening was unrelated to social support, negatively related to good physical health, and, unexpectedly, positively associated with depression.

Prediction of Antibacterial Activity from Physicochemical Properties of Antimicrobial Peptides

PubMed Central

Melo, Manuel N.; Ferre, Rafael; Feliu, Lídia; Bardají, Eduard; Planas, Marta; Castanho, Miguel A. R. B.

2011-01-01

Consensus is gathering that antimicrobial peptides that exert their antibacterial action at the membrane level must reach a local concentration threshold to become active. Studies of peptide interaction with model membranes do identify such disruptive thresholds but demonstrations of the possible correlation of these with the in vivo onset of activity have only recently been proposed. In addition, such thresholds observed in model membranes occur at local peptide concentrations close to full membrane coverage. In this work we fully develop an interaction model of antimicrobial peptides with biological membranes; by exploring the consequences of the underlying partition formalism we arrive at a relationship that provides antibacterial activity prediction from two biophysical parameters: the affinity of the peptide to the membrane and the critical bound peptide to lipid ratio. A straightforward and robust method to implement this relationship, with potential application to high-throughput screening approaches, is presented and tested. In addition, disruptive thresholds in model membranes and the onset of antibacterial peptide activity are shown to occur over the same range of locally bound peptide concentrations (10 to 100 mM), which conciliates the two types of observations. PMID:22194847

QSAR and docking studies on xanthone derivatives for anticancer activity targeting DNA topoisomerase IIα

PubMed Central

Alam, Sarfaraz; Khan, Feroz

2014-01-01

Due to the high mortality rate in India, the identification of novel molecules is important in the development of novel and potent anticancer drugs. Xanthones are natural constituents of plants in the families Bonnetiaceae and Clusiaceae, and comprise oxygenated heterocycles with a variety of biological activities along with an anticancer effect. To explore the anticancer compounds from xanthone derivatives, a quantitative structure activity relationship (QSAR) model was developed by the multiple linear regression method. The structure–activity relationship represented by the QSAR model yielded a high activity–descriptors relationship accuracy (84%) referred by regression coefficient (r2=0.84) and a high activity prediction accuracy (82%). Five molecular descriptors – dielectric energy, group count (hydroxyl), LogP (the logarithm of the partition coefficient between n-octanol and water), shape index basic (order 3), and the solvent-accessible surface area – were significantly correlated with anticancer activity. Using this QSAR model, a set of virtually designed xanthone derivatives was screened out. A molecular docking study was also carried out to predict the molecular interaction between proposed compounds and deoxyribonucleic acid (DNA) topoisomerase IIα. The pharmacokinetics parameters, such as absorption, distribution, metabolism, excretion, and toxicity, were also calculated, and later an appraisal of synthetic accessibility of organic compounds was carried out. The strategy used in this study may provide understanding in designing novel DNA topoisomerase IIα inhibitors, as well as for other cancer targets. PMID:24516330

Augmented multivariate image analysis applied to quantitative structure-activity relationship modeling of the phytotoxicities of benzoxazinone herbicides and related compounds on problematic weeds.

PubMed

Freitas, Mirlaine R; Matias, Stella V B G; Macedo, Renato L G; Freitas, Matheus P; Venturin, Nelson

2013-09-11

Two of major weeds affecting cereal crops worldwide are Avena fatua L. (wild oat) and Lolium rigidum Gaud. (rigid ryegrass). Thus, development of new herbicides against these weeds is required; in line with this, benzoxazinones, their degradation products, and analogues have been shown to be important allelochemicals and natural herbicides. Despite earlier structure-activity studies demonstrating that hydrophobicity (log P) of aminophenoxazines correlates to phytotoxicity, our findings for a series of benzoxazinone derivatives do not show any relationship between phytotoxicity and log P nor with other two usual molecular descriptors. On the other hand, a quantitative structure-activity relationship (QSAR) analysis based on molecular graphs representing structural shape, atomic sizes, and colors to encode other atomic properties performed very accurately for the prediction of phytotoxicities of these compounds against wild oat and rigid ryegrass. Therefore, these QSAR models can be used to estimate the phytotoxicity of new congeners of benzoxazinone herbicides toward A. fatua L. and L. rigidum Gaud.

Analysis of the relationship between end-to-end distance and activity of single-chain antibody against colorectal carcinoma.

PubMed

Zhang, Jianhua; Liu, Shanhong; Shang, Zhigang; Shi, Li; Yun, Jun

2012-08-22

We investigated the relationship of End-to-end distance between VH and VL with different peptide linkers and the activity of single-chain antibodies by computer-aided simulation. First, we developed (G4S)n (where n = 1-9) as the linker to connect VH and VL, and estimated the 3D structure of single-chain Fv antibody (scFv) by homologous modeling. After molecular models were evaluated and optimized, the coordinate system of every protein was built and unified into one coordinate system, and End-to-end distances calculated using 3D space coordinates. After expression and purification of scFv-n with (G4S)n as n = 1, 3, 5, 7 or 9, the immunoreactivity of purified ND-1 scFv-n was determined by ELISA. A multi-factorial relationship model was employed to analyze the structural factors affecting scFv: rn=ABn-ABO2+CDn-CDO2+BCn-BCst2. The relationship between immunoreactivity and r-values revealed that fusion protein structure approached the desired state when the r-value = 3. The immunoreactivity declined as the r-value increased, but when the r-value exceeded a certain threshold, it stabilized. We used a linear relationship to analyze structural factors affecting scFv immunoreactivity.

Modeling Aspects Of Nature Of Science To Preservice Elementary Teachers

NASA Astrophysics Data System (ADS)

Ashcraft, Paul

2007-01-01

Nature of science was modeled using guided inquiry activities in the university classroom with elementary education majors. A physical science content course initially used an Aristotelian model where students discussed the relationship between distance from a constant radiation source and the amount of radiation received based on accepted ``truths'' or principles and concluded that there was an inverse relationship. The class became Galilean in nature, using the scientific method to test that hypothesis. Examining data, the class rejected their hypothesis and concluded that there is an inverse square relationship. Assignments, given before and after the hypothesis testing, show the student's misconceptions and their acceptance of scientifically acceptable conceptions. Answers on exam questions further support this conceptual change. Students spent less class time on the inverse square relationship later when examining electrostatic force, magnetic force, gravity, and planetary solar radiation because the students related this particular experience to other physical relationships.

Brain activity and cognition: a connection from thermodynamics and information theory

PubMed Central

Collell, Guillem; Fauquet, Jordi

2015-01-01

The connection between brain and mind is an important scientific and philosophical question that we are still far from completely understanding. A crucial point to our work is noticing that thermodynamics provides a convenient framework to model brain activity, whereas cognition can be modeled in information-theoretical terms. In fact, several models have been proposed so far from both approaches. A second critical remark is the existence of deep theoretical connections between thermodynamics and information theory. In fact, some well-known authors claim that the laws of thermodynamics are nothing but principles in information theory. Unlike in physics or chemistry, a formalization of the relationship between information and energy is currently lacking in neuroscience. In this paper we propose a framework to connect physical brain and cognitive models by means of the theoretical connections between information theory and thermodynamics. Ultimately, this article aims at providing further insight on the formal relationship between cognition and neural activity. PMID:26136709

Examination of the Relationship between Coach-Athlete Communication Levels and Perceived Motivational Climate for Volleyball Players

ERIC Educational Resources Information Center

Avci, Kübra Seden; Çepikkurt, Fatma; Kale, Esen Kizildag

2018-01-01

The aim of this study was to reveal the relationship between the athlete-coach relationship and the motivational climate created by the coach. In this study, relational survey model was used. The study sample included 96 female volleyball players who are active players at Turkey Women Volleyball 3rd League. "The Coach-Athlete Relationship…

Peptide inhibitors of botulinum neurotoxin serotype A: design, inhibition, cocrystal structures, structure-activity relationship and pharmacophore modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar G.; Swaminathan S.; Kumaran, D.

Clostridium botulinum neurotoxins are classified as Category A bioterrorism agents by the Centers for Disease Control and Prevention (CDC). The seven serotypes (A-G) of the botulinum neurotoxin, the causative agent of the disease botulism, block neurotransmitter release by specifically cleaving one of the three SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins and induce flaccid paralysis. Using a structure-based drug-design approach, a number of peptide inhibitors were designed and their inhibitory activity against botulinum serotype A (BoNT/A) protease was determined. The most potent peptide, RRGF, inhibited BoNT/A protease with an IC{sub 50} of 0.9 {micro}M and a K{sub i} ofmore » 358 nM. High-resolution crystal structures of various peptide inhibitors in complex with the BoNT/A protease domain were also determined. Based on the inhibitory activities and the atomic interactions deduced from the cocrystal structures, the structure-activity relationship was analyzed and a pharmacophore model was developed. Unlike the currently available models, this pharmacophore model is based on a number of enzyme-inhibitor peptide cocrystal structures and improved the existing models significantly, incorporating new features.« less

Peptide inhibitors of botulinum neurotoxin serotype A: design, inhibition, cocrystal structures, structure-activity relationship and pharmacophore modeling.

PubMed

Kumar, Gyanendra; Kumaran, Desigan; Ahmed, S Ashraf; Swaminathan, Subramanyam

2012-05-01

Clostridium botulinum neurotoxins are classified as Category A bioterrorism agents by the Centers for Disease Control and Prevention (CDC). The seven serotypes (A-G) of the botulinum neurotoxin, the causative agent of the disease botulism, block neurotransmitter release by specifically cleaving one of the three SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins and induce flaccid paralysis. Using a structure-based drug-design approach, a number of peptide inhibitors were designed and their inhibitory activity against botulinum serotype A (BoNT/A) protease was determined. The most potent peptide, RRGF, inhibited BoNT/A protease with an IC(50) of 0.9 µM and a K(i) of 358 nM. High-resolution crystal structures of various peptide inhibitors in complex with the BoNT/A protease domain were also determined. Based on the inhibitory activities and the atomic interactions deduced from the cocrystal structures, the structure-activity relationship was analyzed and a pharmacophore model was developed. Unlike the currently available models, this pharmacophore model is based on a number of enzyme-inhibitor peptide cocrystal structures and improved the existing models significantly, incorporating new features. © 2012 International Union of Crystallography

Physical activity and incident type 2 diabetes mellitus: a systematic review and dose-response meta-analysis of prospective cohort studies.

PubMed

Smith, Andrea D; Crippa, Alessio; Woodcock, James; Brage, Søren

2016-12-01

Inverse associations between physical activity (PA) and type 2 diabetes mellitus are well known. However, the shape of the dose-response relationship is still uncertain. This review synthesises results from longitudinal studies in general populations and uses non-linear models of the association between PA and incident type 2 diabetes. A systematic literature search identified 28 prospective studies on leisure-time PA (LTPA) or total PA and risk of type 2 diabetes. PA exposures were converted into metabolic equivalent of task (MET) h/week and marginal MET (MMET) h/week, a measure only considering energy expended above resting metabolic rate. Restricted cubic splines were used to model the exposure-disease relationship. Our results suggest an overall non-linear relationship; using the cubic spline model we found a risk reduction of 26% (95% CI 20%, 31%) for type 2 diabetes among those who achieved 11.25 MET h/week (equivalent to 150 min/week of moderate activity) relative to inactive individuals. Achieving twice this amount of PA was associated with a risk reduction of 36% (95% CI 27%, 46%), with further reductions at higher doses (60 MET h/week, risk reduction of 53%). Results for the MMET h/week dose-response curve were similar for moderate intensity PA, but benefits were greater for higher intensity PA and smaller for lower intensity activity. Higher levels of LTPA were associated with substantially lower incidence of type 2 diabetes in the general population. The relationship between LTPA and type 2 diabetes was curvilinear; the greatest relative benefits are achieved at low levels of activity, but additional benefits can be realised at exposures considerably higher than those prescribed by public health recommendations.

The relationship between physical activity, meaning in life, and subjective vitality in community-dwelling older adults.

PubMed

Ju, Haewon

2017-11-01

The present study examined the potential contribution of meaning in life to the relationship between physical activity and subjective vitality in older adults. Two-hundred and fifty community-dwelling elders completed the instruments assessing physical activity, meaning in life, and subjective vitality. Results from structural equation modeling indicated that physical activity was positively associated with both meaning in life and subjective vitality. Further, the relationship between physical activity and vitality was partially mediated by meaning in life. Although previous studies have consistently found a positive impact of physical activity on vitality, the current study suggested that it is more productive to focus not only on physical activity, but also on meaning in life, in order to vitalize elders. Further, a focus on meaning in life can be a productive way to continue to vitalize older adults who are unable to engage in regular physical activity. Copyright © 2017 Elsevier B.V. All rights reserved.

Activites to Support and Assess Student Understanding of Earth Data

NASA Astrophysics Data System (ADS)

Prothero, W. A.; Regev, J.

2004-12-01

In order to use data effectively, learners must construct a mental model that allows them to understand and express spatial relationships in data, relationships between different data types, and relationships between the data and a theoretical model. Another important skill is the ability to identify gross patterns and distinguish them from details that may require increasingly sophisticated models. Students must also be able to express their understanding, both to help them frame their understanding for themselves, and for assessment purposes. Research in learning unequivocally shows that writing about a subject increases understanding of that subject. In UCSB's general education oceanography class, a series of increasingly demanding activities culminates in two science papers that use earth data. These activities are: 1) homework problems, 2) in-class short writing activities, 3) lab section exploration activities and presentations, and 4) the science paper. The subjects of the two papers are: Plate Tectonics and Ocean and Climate. Each student is a member of a group that adopts a country and must relate their paper to the environment of their country. Data are accessed using the "Our Dynamic Planet" and "Global Ocean Data Viewer" (GLODV) CD's. These are integrated into EarthEd Online, a software package which supports online writing, review, commenting, and return to the student. It also supports auto-graded homework assignments, grade calculation, and other class management functions. The writing assignments emphasize the construction of a scientific argument. This process is explained explicitly, requiring statements that: 1) include an observation or description of an observation (e.g. elevation profiles, quakes), 2) name features based on the observation (e.g. trench, ridge), 3) describe of features (e.g. trends NW, xxxkm long), 4) describe relationships between features (e.g. quakes are parallel to trench), 5) describe a model or theory (e.g. cartoon type representation of a subduction zone), and 6) describe the relationship between the model/theory and the data. Students generate and select data representations with the appropriate data display software, which seamlessly uploads each generated image to the student's personal storage area (on the class server). There they are available to be linked to the writing text. The assignment is "handed in" online, where it is commented, graded according to a rubric, and returned. Students rate the writing assignment as one of the most effective activities that contributes to their learning in the course.

Your Face is Your Fortune: Does Adolescent Attractiveness Predict Intimate Relationships Later in Life?

PubMed

Karraker, Amelia; Sicinski, Kamil; Moynihan, Donald

2017-01-01

A growing literature documents the importance of physical attractiveness in young and middle adulthood for romantic, marital, and sexual relationships, but little is known about how attractiveness in adolescence matters to intimate relationships in later life. We ask: does attractiveness early in life convey ongoing benefits late in life, or do such benefits erode over time? We use multivariate regression models and more than 50 years of data from the Wisconsin Longitudinal Study to examine the connections between adolescent physical attractiveness and intimate relationships (i.e., sexual activity and access to potential sexual partners) in later life. We find that adolescent attractiveness facilitates sexual activity in later life. This relationship is largely driven by attractiveness increasing the probability of having access to potential sexual partners. However, attractiveness is not related to sexual activity among married couples, even after controlling for marital duration. Men, those in good health, and wealthier individuals are also more likely to engage in several facets of intimate relationships. These findings highlight the importance of relationship context for later life sexual activity and begin to explicate the pathways through which factors across the life course-particularly attractiveness-influence sexual activity in later life. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

After-School Activities, Misbehavior in School, and Delinquency from the End of Elementary School through the Beginning of High School: A Test of Social Development Model Hypotheses

ERIC Educational Resources Information Center

Fleming, Charles B.; Catalano, Richard F.; Mazza, James J.; Brown, Eric C.; Haggerty, Kevin P.; Harachi, Tracy W.

2008-01-01

Annual survey data on 776 students from sixth through ninth grade were used to examine the relationships among after-school activities, misbehavior in school, and delinquency. The social development model hypothesizes that antisocial behavior in one developmental time period leads to less involvement in activities and interactions that have…

Relationship beliefs and illness appraisals are differentially associated with specific ways of coping in spouses of patients with type 2 diabetes.

PubMed

Johnson, Matthew D; Anderson, Jared R; Wilcox, Allison; Walker, Ann; Robbins, David C; Lewis, Virginia L

2013-01-01

Using data from 117 spouses of patients diagnosed with type 2 diabetes and multiple-group path analysis, the current study explored the association of four relationship beliefs (satisfaction, sacrifice, confidence and instability) and four diabetes appraisals (consequences, distress, control and efficacy) with illness-specific coping behaviour: active engagement, protective buffering and overprotection. The potential moderating effect of gender was also tested. Results indicated gender did moderate the associations among the variables in the model, with the association of relationship satisfaction and active engagement being significantly stronger for men, while diabetes control was more strongly related to protective buffering for women. The only variables associated with active engagement were three relationship-specific cognitions: higher levels of relationship satisfaction (for men only), satisfaction with sacrifice and relationship confidence were all related to higher active engagement. The diabetes appraisals were the only variables associated with protective buffering and overprotection. Higher diabetes distress and diabetes control (for women only) and lower diabetes efficacy were predictive of greater protective buffering. Lower diabetes efficacy and higher diabetes control were associated with greater overprotection. Implications for theory, research and practice are discussed.

Physical activity and neighborhood resources in high school girls.

PubMed

Pate, Russell R; Colabianchi, Natalie; Porter, Dwayne; Almeida, Maria J; Lobelo, Felipe; Dowda, Marsha

2008-05-01

Physical activity behavior is influenced by a person's physical environment, but few studies have used objective measures to study the influences of the physical environment on physical activity behavior in youth. The purpose of this study was to examine the relationship between selected neighborhood physical activity resources and physical activity levels in high school girls. Participants were students in schools that had participated in a large physical activity intervention trial. The 3-Day Physical Activity Recall was completed by 1506 12th-grade girls. Data on physical activity facilities and resources in the participating communities were collected using a variety of methods. Physical activity resources within a 0.75-mile street-network buffer around each girl's home were counted using ArcGIS, version 9.1. Mixed-model regression models were used to determine if there was a relationship between three physical activity variables and the number of physical activity resources within the 0.75-mile buffer. Data were collected in 2002-2003 and analyzed in 2006-2007. On average, 3.5 physical activity resources (e.g., schools, parks, commercial facilities) were located within the 0.75-mile street-network buffer. Thirty-six percent of the girls had no physical activity resource within the buffer. When multiple physical activity resources were considered, the number of commercial physical activity facilities was significantly associated with reported vigorous physical activity, and the number of parks was associated with total METs in white girls. Multiple physical activity resources within a 0.75-mile street-network buffer around adolescent girls' homes are associated physical activity in those girls. Several types of resources are associated with vigorous physical activity and total activity in adolescent girls. Future studies should examine the temporal and causal relationships between the physical environment, physical activity, and health outcomes related to physical activity.

Representation of activity in images using geospatial temporal graphs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brost, Randolph; McLendon, III, William C.; Parekh, Ojas D.

Various technologies pertaining to modeling patterns of activity observed in remote sensing images using geospatial-temporal graphs are described herein. Graphs are constructed by representing objects in remote sensing images as nodes, and connecting nodes with undirected edges representing either distance or adjacency relationships between objects and directed edges representing changes in time. Activity patterns may be discerned from the graphs by coding nodes representing persistent objects like buildings differently from nodes representing ephemeral objects like vehicles, and examining the geospatial-temporal relationships of ephemeral nodes within the graph.

A brain-region-based meta-analysis method utilizing the Apriori algorithm.

PubMed

Niu, Zhendong; Nie, Yaoxin; Zhou, Qian; Zhu, Linlin; Wei, Jieyao

2016-05-18

Brain network connectivity modeling is a crucial method for studying the brain's cognitive functions. Meta-analyses can unearth reliable results from individual studies. Meta-analytic connectivity modeling is a connectivity analysis method based on regions of interest (ROIs) which showed that meta-analyses could be used to discover brain network connectivity. In this paper, we propose a new meta-analysis method that can be used to find network connectivity models based on the Apriori algorithm, which has the potential to derive brain network connectivity models from activation information in the literature, without requiring ROIs. This method first extracts activation information from experimental studies that use cognitive tasks of the same category, and then maps the activation information to corresponding brain areas by using the automatic anatomical label atlas, after which the activation rate of these brain areas is calculated. Finally, using these brain areas, a potential brain network connectivity model is calculated based on the Apriori algorithm. The present study used this method to conduct a mining analysis on the citations in a language review article by Price (Neuroimage 62(2):816-847, 2012). The results showed that the obtained network connectivity model was consistent with that reported by Price. The proposed method is helpful to find brain network connectivity by mining the co-activation relationships among brain regions. Furthermore, results of the co-activation relationship analysis can be used as a priori knowledge for the corresponding dynamic causal modeling analysis, possibly achieving a significant dimension-reducing effect, thus increasing the efficiency of the dynamic causal modeling analysis.

Development of an in Silico Model of DPPH• Free Radical Scavenging Capacity: Prediction of Antioxidant Activity of Coumarin Type Compounds.

PubMed

Goya Jorge, Elizabeth; Rayar, Anita Maria; Barigye, Stephen J; Jorge Rodríguez, María Elisa; Sylla-Iyarreta Veitía, Maité

2016-06-07

A quantitative structure-activity relationship (QSAR) study of the 2,2-diphenyl-l-picrylhydrazyl (DPPH•) radical scavenging ability of 1373 chemical compounds, using DRAGON molecular descriptors (MD) and the neural network technique, a technique based on the multilayer multilayer perceptron (MLP), was developed. The built model demonstrated a satisfactory performance for the training ( R 2 = 0.713 ) and test set ( Q ext 2 = 0.654 ) , respectively. To gain greater insight on the relevance of the MD contained in the MLP model, sensitivity and principal component analyses were performed. Moreover, structural and mechanistic interpretation was carried out to comprehend the relationship of the variables in the model with the modeled property. The constructed MLP model was employed to predict the radical scavenging ability for a group of coumarin-type compounds. Finally, in order to validate the model's predictions, an in vitro assay for one of the compounds (4-hydroxycoumarin) was performed, showing a satisfactory proximity between the experimental and predicted pIC50 values.

SOD activity of carboxyfullerenes predicts their neuroprotective efficacy: A structure-activity study

PubMed Central

Ali, Sameh Saad; Hardt, Joshua I.; Dugan, Laura L.

2008-01-01

Superoxide radical anion is a biologically important oxidant that has been linked to tissue injury and inflammation in several diseases. Here we carried out a structure-activity study on 6 different carboxyfullerene superoxide dismutase (SOD) mimetics with distinct electronic and biophysical characteristics. Neurotoxicity via NMDA receptors, which involves intracellular superoxide, was used as a model to evaluate structure-activity relationships between reactivity towards superoxide and neuronal rescue by these drugs. A significant correlation between neuroprotection by carboxyfullerenes and their ki towards superoxide radical was observed. Computer-assistant molecular modeling demonstrated that the reactivity towards superoxide is sensitive to changes in dipole moment which are dictated not only by the number of carboxyl groups, but also by their distribution on the fullerene ball. These results indicate that the SOD activity of these cell-permeable compounds predicts neuroprotection, and establishes a structure-activity relationship to aid in future studies on the biology of superoxide across disciplines. PMID:18656425

Forest growth and timber quality: crown models and simulation methods for sustainable forest management

Treesearch

Dennis P. Dykstra; Robert A. Monserud

2009-01-01

The purpose of the international conference from which these proceedings are drawn was to explore relationships between forest management activities and timber quality. Sessions were organized to explore models and simulation methodologies that contribute to an understanding of tree development over time and the ways that management and harvesting activities can...

A New Model to Study Sleep Deprivation-Induced Seizure

PubMed Central

Lucey, Brendan P.; Leahy, Averi; Rosas, Regine; Shaw, Paul J.

2015-01-01

Background and Study Objectives: A relationship between sleep and seizures is well-described in both humans and rodent animal models; however, the mechanism underlying this relationship is unknown. Using Drosophila melanogaster mutants with seizure phenotypes, we demonstrate that seizure activity can be modified by sleep deprivation. Design: Seizure activity was evaluated in an adult bang-sensitive seizure mutant, stress sensitive B (sesB9ed4), and in an adult temperature sensitive seizure mutant seizure (seits1) under baseline and following 12 h of sleep deprivation. The long-term effect of sleep deprivation on young, immature sesB9ed4 flies was also assessed. Setting: Laboratory. Participants: Drosophila melanogaster. Interventions: Sleep deprivation. Measurements and Results: Sleep deprivation increased seizure susceptibility in adult sesB9ed4/+ and seits1 mutant flies. Sleep deprivation also increased seizure susceptibility when sesB was disrupted using RNAi. The effect of sleep deprivation on seizure activity was reduced when sesB9ed4/+ flies were given the anti-seizure drug, valproic acid. In contrast to adult flies, sleep deprivation during early fly development resulted in chronic seizure susceptibility when sesB9ed4/+ became adults. Conclusions: These findings show that Drosophila is a model organism for investigating the relationship between sleep and seizure activity. Citation: Lucey BP, Leahy A, Rosas R, Shaw PJ. A new model to study sleep deprivation-induced seizure. SLEEP 2015;38(5):777–785. PMID:25515102

On the Relationship between Variational Level Set-Based and SOM-Based Active Contours

PubMed Central

Abdelsamea, Mohammed M.; Gnecco, Giorgio; Gaber, Mohamed Medhat; Elyan, Eyad

2015-01-01

Most Active Contour Models (ACMs) deal with the image segmentation problem as a functional optimization problem, as they work on dividing an image into several regions by optimizing a suitable functional. Among ACMs, variational level set methods have been used to build an active contour with the aim of modeling arbitrarily complex shapes. Moreover, they can handle also topological changes of the contours. Self-Organizing Maps (SOMs) have attracted the attention of many computer vision scientists, particularly in modeling an active contour based on the idea of utilizing the prototypes (weights) of a SOM to control the evolution of the contour. SOM-based models have been proposed in general with the aim of exploiting the specific ability of SOMs to learn the edge-map information via their topology preservation property and overcoming some drawbacks of other ACMs, such as trapping into local minima of the image energy functional to be minimized in such models. In this survey, we illustrate the main concepts of variational level set-based ACMs, SOM-based ACMs, and their relationship and review in a comprehensive fashion the development of their state-of-the-art models from a machine learning perspective, with a focus on their strengths and weaknesses. PMID:25960736

Relationship between self-efficacy and physical activity among patients with type 2 diabetes.

PubMed

Dutton, Gareth R; Tan, Fei; Provost, Bridgette C; Sorenson, Jamie L; Allen, Brandon; Smith, Dawn

2009-06-01

While previous studies indicate a significant relationship between self-efficacy and physical activity, less research has focused on this relationship among patients with type 2 diabetes. The purpose of this investigation was to examine whether self-efficacy mediated the relationship between participation in a 1-month, print-based physical activity intervention and improvements in activity levels. Participants (N = 85; mean age = 57; 73% Caucasian; 69% female) were recruited from a community diabetes center. The intervention was individually-tailored based on theoretical constructs, including self-efficacy. After controlling for age, baseline activity, and baseline self-efficacy, the tailored intervention was associated with significant improvements in physical activity, 95% CI [23.01, 271.68] as well as self-efficacy, CI [0.02, 3.48]. There was an indirect effect of treatment on physical activity through self-efficacy, CI [0.77, 73.11], and the direct effect of treatment on physical activity was no longer significant, CI [-7.33, 253.40], after the influences of self-efficacy change were accounted for in the model. Results supported a mediation effect, such that the treatment effect on physical activity was completely mediated by changes in self-efficacy. Although replication is needed, results support the theoretical rationale for targeting self-efficacy to promote physical activity among patients with type 2 diabetes.

A Multifaceted Model of Training in Psychological Assessment.

ERIC Educational Resources Information Center

Levy, Leon H.

Much of the controversy over training in diagnostic testing between internship training centers and universities results from the implicit producer-consumer relationship which exists between them. A collaborative relationship is proposed as an alternative, in which the training activities of universities and internship centers are seen as…

Does community type moderate the relationship between parent perceptions of the neighborhood and physical activity in children?

PubMed

Durand, Casey P; Dunton, Genevieve F; Spruijt-Metz, Donna; Pentz, Mary Ann

2012-01-01

To examine whether residing in a community designed to promote physical activity moderates the relationship between parent perceptions of the neighborhood and general physical activity or active commuting to school in their children. Cross-sectional. San Bernardino County, California. Three hundred sixty-five families (one parent and one child in grades four through eight). Eighty-five reside in a smart growth community designed to be more conducive to physical activity. Parent perceptions assessed using the Neighborhood Environment Walkability Scale (NEWS). General child physical activity was measured using accelerometers, and active commuting was self-reported by children. Two sets of regressions were performed: one for general physical activity, and one for active commuting. Separate models were run in the two sets for each of the 14 NEWS factors, while controlling for demographics. For general physical activity, walking infrastructure, lack of cul-de-sacs, and social interaction had significant main effect associations (p ≤ .05). No factors were moderated by community. The relationships between active commuting to school and perceived crime, traffic hazards, hilliness, physical barriers, cul-de-sac connectivity, aesthetics, and walking infrastructure were significant for those in the smart growth community only (p ≤ .05). Living in an activity-friendly environment is associated with positive relationships between parent perceptions and active commuting behaviors in children. Future interventions should account for both the perceived neighborhood environment and available physical activity infrastructure.

Longitudinal associations between physical activity and depression scores in Swedish women followed 32 years.

PubMed

Gudmundsson, P; Lindwall, M; Gustafson, D R; Östling, S; Hällström, T; Waern, M; Skoog, I

2015-12-01

Physical activity is negatively associated with depressive symptoms. However, few studies consider dynamic associations of changes in physical activity and reciprocal relationships. This study aimed to perform comprehensive evaluations of relationships between physical activity and depression scores in women followed from mid- to late life. The Prospective Population Study of Women in Gothenburg, Sweden, provided repeated measures of self-reported physical activity and depressive symptoms between 1974 and 2005 (baseline N = 676, 84.5% response rate). Depressive symptoms were assessed using the Montgomery-Åsberg Depression Rating Scale, and physical activity was evaluated by the Saltin-Grimby Physical Activity Level Scale. Latent growth curve analyses were used to evaluate associations of change, and cross-lagged models were used to study the reciprocal relationship between physical activity and depression scores. At baseline, lower levels of physical activity were related to higher depression scores. Individuals with decreasing physical activity over time evidenced higher depression scores at 32-year follow-up. Higher average baseline depression score was related to declining levels of physical activity at subsequent examinations. Reduced physical activity may be a long-term consequence of depression. It is important to address individual changes in physical activity and not merely absolute levels of physical activity in relationship to depression. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Physical activity and the mediating effect of fear, depression, anxiety, and catastrophizing on pain related disability in people with chronic low back pain.

PubMed

Marshall, Paul W M; Schabrun, Siobhan; Knox, Michael F

2017-01-01

Chronic low back pain is a worldwide burden that is not being abated with our current knowledge and treatment of the condition. The fear-avoidance model is used to explain the relationship between pain and disability in patients with chronic low back pain. However there are gaps in empirical support for pathways proposed within this model, and no evidence exists as to whether physical activity moderates these pathways. This was a cross-sectional study of 218 people with chronic low back pain. Multiple mediation analyses were conducted to determine the role of fear, catastrophizing, depression, and anxiety in the relationship between pain and disability. Separate analyses were performed with physical activity as the moderator. Individuals were classified as performing regular structured physical activity if they described on average once per week for > 30-minutes an activity classified at least moderate intensity (≥ 4-6 METs), activity prescribed by an allied health professional for their back pain, leisure time sport or recreation, or self-directed physical activity such as resistance exercise. Fear, catastrophizing, and depression significantly mediated the relationship between pain and disability (p<0.001). However the mediating effect of catastrophizing was conditional upon weekly physical activity. That is, the indirect effect for catastrophizing mediating the relationship between pain and disability was only significant for individuals reporting weekly physical activity (B = 1.31, 95% CI 0.44 to 2.23), compared to individuals reporting no weekly physical activity (B = 0.21, 95% CI -0.50 to 0.97). Catastrophizing also mediated the relationship between pain and fear (B = 0.37, 95% CI 0.15 to 0.62), with higher scores explaining 53% of the total effect of pain on fear. These results support previous findings about the importance of fear and depression as factors that should be targeted in low back pain patients to reduce back pain related disability. We have also extended understanding for the mediating effect of catastrophizing on back pain related disability. Back pain patients engaged with regular physical activity may require counselling with regards to negative pain perceptions.

Physical activity and the mediating effect of fear, depression, anxiety, and catastrophizing on pain related disability in people with chronic low back pain

PubMed Central

Marshall, Paul W. M.; Schabrun, Siobhan; Knox, Michael F.

2017-01-01

Background Chronic low back pain is a worldwide burden that is not being abated with our current knowledge and treatment of the condition. The fear-avoidance model is used to explain the relationship between pain and disability in patients with chronic low back pain. However there are gaps in empirical support for pathways proposed within this model, and no evidence exists as to whether physical activity moderates these pathways. Methods This was a cross-sectional study of 218 people with chronic low back pain. Multiple mediation analyses were conducted to determine the role of fear, catastrophizing, depression, and anxiety in the relationship between pain and disability. Separate analyses were performed with physical activity as the moderator. Individuals were classified as performing regular structured physical activity if they described on average once per week for > 30-minutes an activity classified at least moderate intensity (≥ 4–6 METs), activity prescribed by an allied health professional for their back pain, leisure time sport or recreation, or self-directed physical activity such as resistance exercise. Results Fear, catastrophizing, and depression significantly mediated the relationship between pain and disability (p<0.001). However the mediating effect of catastrophizing was conditional upon weekly physical activity. That is, the indirect effect for catastrophizing mediating the relationship between pain and disability was only significant for individuals reporting weekly physical activity (B = 1.31, 95% CI 0.44 to 2.23), compared to individuals reporting no weekly physical activity (B = 0.21, 95% CI -0.50 to 0.97). Catastrophizing also mediated the relationship between pain and fear (B = 0.37, 95% CI 0.15 to 0.62), with higher scores explaining 53% of the total effect of pain on fear. Conclusions These results support previous findings about the importance of fear and depression as factors that should be targeted in low back pain patients to reduce back pain related disability. We have also extended understanding for the mediating effect of catastrophizing on back pain related disability. Back pain patients engaged with regular physical activity may require counselling with regards to negative pain perceptions. PMID:28686644

Reduction in leisure activity and well-being during the transition to widowhood.

PubMed

Janke, Megan C; Nimrod, Galit; Kleiber, Douglas A

2008-01-01

There is relatively little evidence available about how leisure involvement changes with the death of a spouse and even less about how leisure activity is associated with the health and well-being of widows during this transition. Using data from the Americans Changing Lives (ACL) dataset, this study of 154 widows investigated change in leisure involvement during the transition to widowhood and examined the relationship between leisure activity reduction and widows' well-being. Results indicated a majority of widows reduced their involvement in leisure activity. Path models revealed that depressive symptoms and recovery from spousal loss were predictors of activity reduction, providing more support for the causal relationship of well-being influencing activity involvement than for activity influencing well-being.

Changes in physical activity, self-efficacy and depressive symptoms in adolescent girls.

PubMed

Neissaar, Inga; Raudsepp, Lennart

2011-08-01

The purpose of this study was to examine the longitudinal relationships between naturally occurring changes in leisure-time physical activity, depressive symptoms and self-efficacy in adolescent girls. We also aimed to test whether depressive symptoms would moderate the self-efficacy-physical activity relationship. Participants were 181 urban adolescent girls. Physical activity was measured using the 3-Day Physical Activity Recall. Self-efficacy and depressive symptoms were assessed using questionnaires. Body height and body mass were measured and body mass index (BMI) was calculated. Data were collected on three occasions over a 2-year period. There was a decrease in physical activity and self-efficacy and increase in depressive symptoms across three measurement occasions. There were statistically significant and negative relationships between initial level and change for physical activity and depressive symptoms. Initially higher levels of physical activity were related with initially lower levels of depressive symptoms, and change in physical activity across time was inversely associated with change in levels of depressive symptoms across measurements. There were statistically significant and positive relationships between initial level and change for physical activity and self-efficacy after controlling effect of BMI. Latent growth modeling (LGM) also indicated a moderating effect of depressive symptoms on the self-efficacy-physical activity relationship. Girls who had high initial levels of self-efficacy and smaller increases in depressive symptoms had the lowest decline in physical activity participation. Our results encourage the design of interventions that reduce depressive symptoms and increase self-efficacy as a possible of means of increasing adolescent girls' physical activity.

Non-linear quantitative structure-activity relationship for adenine derivatives as competitive inhibitors of adenosine deaminase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadat Hayatshahi, Sayyed Hamed; Abdolmaleki, Parviz; Safarian, Shahrokh

2005-12-16

Logistic regression and artificial neural networks have been developed as two non-linear models to establish quantitative structure-activity relationships between structural descriptors and biochemical activity of adenosine based competitive inhibitors, toward adenosine deaminase. The training set included 24 compounds with known k {sub i} values. The models were trained to solve two-class problems. Unlike the previous work in which multiple linear regression was used, the highest of positive charge on the molecules was recognized to be in close relation with their inhibition activity, while the electric charge on atom N1 of adenosine was found to be a poor descriptor. Consequently, themore » previously developed equation was improved and the newly formed one could predict the class of 91.66% of compounds correctly. Also optimized 2-3-1 and 3-4-1 neural networks could increase this rate to 95.83%.« less

Three-dimensional quantitative structure-activity relationship study on anti-cancer activity of 3,4-dihydroquinazoline derivatives against human lung cancer A549 cells

NASA Astrophysics Data System (ADS)

Cho, Sehyeon; Choi, Min Ji; Kim, Minju; Lee, Sunhoe; Lee, Jinsung; Lee, Seok Joon; Cho, Haelim; Lee, Kyung-Tae; Lee, Jae Yeol

2015-03-01

A series of 3,4-dihydroquinazoline derivatives with anti-cancer activities against human lung cancer A549 cells were subjected to three-dimensional quantitative structure-activity relationship (3D-QSAR) studies using the comparative molecular similarity indices analysis (CoMSIA) approaches. The most potent compound, 1 was used to align the molecules. As a result, the best prediction was obtained with CoMSIA combined the steric, electrostatic, hydrophobic, hydrogen bond donor, and hydrogen bond acceptor fields (q2 = 0.720, r2 = 0.897). This model was validated by an external test set of 6 compounds giving satisfactory predictive r2 value of 0.923 as well as the scrambling stability test. This model would guide the design of potent 3,4-dihydroquinazoline derivatives as anti-cancer agent for the treatment of human lung cancer.

The Challenge Posed by Geomagnetic Activity to Electric Power Reliability: Evidence From England and Wales

NASA Astrophysics Data System (ADS)

Forbes, Kevin F.; St. Cyr, O. C.

2017-10-01

This paper addresses whether geomagnetic activity challenged the reliability of the electric power system during part of the declining phase of solar cycle 23. Operations by National Grid in England and Wales are examined over the period of 11 March 2003 through 31 March 2005. This paper examines the relationship between measures of geomagnetic activity and a metric of challenged electric power reliability known as the net imbalance volume (NIV). Measured in megawatt hours, NIV represents the sum of all energy deployments initiated by the system operator to balance the electric power system. The relationship between geomagnetic activity and NIV is assessed using a multivariate econometric model. The model was estimated using half-hour settlement data over the period of 11 March 2003 through 31 December 2004. The results indicate that geomagnetic activity had a demonstrable effect on NIV over the sample period. Based on the parameter estimates, out-of-sample predictions of NIV were generated for each half hour over the period of 1 January to 31 March 2005. Consistent with the existence of a causal relationship between geomagnetic activity and the electricity market imbalance, the root-mean-square error of the out-of-sample predictions of NIV is smaller; that is, the predictions are more accurate, when the statistically significant estimated effects of geomagnetic activity are included as drivers in the predictions.

On the virtues of automated quantitative structure-activity relationship: the new kid on the block.

PubMed

de Oliveira, Marcelo T; Katekawa, Edson

2018-02-01

Quantitative structure-activity relationship (QSAR) has proved to be an invaluable tool in medicinal chemistry. Data availability at unprecedented levels through various databases have collaborated to a resurgence in the interest for QSAR. In this context, rapid generation of quality predictive models is highly desirable for hit identification and lead optimization. We showcase the application of an automated QSAR approach, which randomly selects multiple training/test sets and utilizes machine-learning algorithms to generate predictive models. Results demonstrate that AutoQSAR produces models of improved or similar quality to those generated by practitioners in the field but in just a fraction of the time. Despite the potential of the concept to the benefit of the community, the AutoQSAR opportunity has been largely undervalued.

Modeling the Prospective Relationships of Impairment, Injury Severity, and Participation to Quality of Life Following Traumatic Brain Injury

PubMed Central

Kalpinski, Ryan J.; Williamson, Meredith L. C.; Elliott, Timothy R.; Berry, Jack W.; Underhill, Andrea T.; Fine, Philip R.

2013-01-01

Identifying reliable predictors of positive adjustment following traumatic brain injury (TBI) remains an important area of inquiry. Unfortunately, much of available research examines direct relationships between predictor variables and outcomes without attending to the contextual relationships that can exist between predictor variables. Relying on theoretical models of well-being, we examined a theoretical model of adjustment in which the capacity to engage in intentional activities would be prospectively associated with greater participation, which in turn would predict subsequent life satisfaction and perceived health assessed at a later time. Structural equation modeling of data collected from 312 individuals (226 men, 86 women) with TBI revealed that two elements of participation—mobility and occupational activities—mediated the prospective influence of functional independence and injury severity to optimal adjustment 60 months following medical discharge for TBI. The model accounted for 21% of the variance in life satisfaction and 23% of the variance in self-rated health. Results indicate that the effects of functional independence and injury severity to optimal adjustment over time may be best understood in the context of participation in meaningful, productive activities. Implications for theoretical models of well-being and for clinical interventions that promote adjustmentafter TBI are discussed. PMID:24199186

Toxicity of ionic liquids: database and prediction via quantitative structure-activity relationship method.

PubMed

Zhao, Yongsheng; Zhao, Jihong; Huang, Ying; Zhou, Qing; Zhang, Xiangping; Zhang, Suojiang

2014-08-15

A comprehensive database on toxicity of ionic liquids (ILs) is established. The database includes over 4000 pieces of data. Based on the database, the relationship between IL's structure and its toxicity has been analyzed qualitatively. Furthermore, Quantitative Structure-Activity relationships (QSAR) model is conducted to predict the toxicities (EC50 values) of various ILs toward the Leukemia rat cell line IPC-81. Four parameters selected by the heuristic method (HM) are used to perform the studies of multiple linear regression (MLR) and support vector machine (SVM). The squared correlation coefficient (R(2)) and the root mean square error (RMSE) of training sets by two QSAR models are 0.918 and 0.959, 0.258 and 0.179, respectively. The prediction R(2) and RMSE of QSAR test sets by MLR model are 0.892 and 0.329, by SVM model are 0.958 and 0.234, respectively. The nonlinear model developed by SVM algorithm is much outperformed MLR, which indicates that SVM model is more reliable in the prediction of toxicity of ILs. This study shows that increasing the relative number of O atoms of molecules leads to decrease in the toxicity of ILs. Copyright © 2014 Elsevier B.V. All rights reserved.

Is there a relationship between primary school children's enjoyment of recess physical activities and health-related quality of life? A cross-sectional exploratory study.

PubMed

Hyndman, Brendon; Benson, Amanda C; Lester, Leanne; Telford, Amanda

2017-03-01

Issue addressed An important strategy for increasing children's physical activity is to enhance children's opportunities for school recess physical activities, yet little is known about the influence of school recess physical activities on children's health-related quality of life (HRQOL). The purpose of the present study was to explore the relationship between Australian primary school children's enjoyment of recess physical activities and HRQOL. Methods The study consisted of children at two Australian primary schools (n=105) aged 8-12 years. The Lunchtime Enjoyment Activity and Play questionnaire was used to measure school children's enjoyment of school recess physical activities. The Pediatric Quality of Life Inventory 4.0 was used to measure children's HRQOL. Researchers applied linear regression modelling in STATA (ver. 13.0) to investigate the relationship between children's enjoyment of school recess physical activities and HRQOL. Results It was discovered that primary school children's enjoyment of more vigorous-type school recess physical activities and playing in a range of weather conditions was associated with children's improved HRQOL. Conclusion The findings from this study suggest that health providers and researchers should consider providing primary school children with opportunities and facilities for more vigorous-intensity school recess physical activities as a key strategy to enhance children's HRQOL. So what? Considering a social-ecological model framework of the key predictors of children's enjoyment of school recess physical activities may provide valuable insight for school health providers into the multiple levels of influence on children's HRQOL when developing school settings and activities for school recess.

SimRiver: Environmental Modeling Software for the Science Classroom

ERIC Educational Resources Information Center

Hoffer, Jeannette; Mayama, Shigeki; Lingle, Kristin; Conroy, Kathryn; Julius, Matthew

2011-01-01

While students may acknowledge the impact that land use and development have on our environment, they do not necessarily understand the relationship between human activities and ecosystem responses. Therefore, the nature of the relationships leaves the science teacher to most often present information in a purely narrative form without any…

A framework for identifying public research priorities: an application in forestry research.

Treesearch

Glenn Fox

1986-01-01

Discusses attempts to model and measure the relationship between research and development activity and the rate and nature of technological change in recent decades. Reviews efforts to model optimal research resource allocation, and presents a model for southern pine forestry research.

The power of an ontology-driven developmental toxicity database for data mining and computational modeling

EPA Science Inventory

Modeling of developmental toxicology presents a significant challenge to computational toxicology due to endpoint complexity and lack of data coverage. These challenges largely account for the relatively few modeling successes using the structure–activity relationship (SAR) parad...

Temperature sensitivity of soil microbial activity modeled by the square root equation as a unifying model to differentiate between direct temperature effects and microbial community adaptation.

PubMed

Bååth, Erland

2018-07-01

Numerous models have been used to express the temperature sensitivity of microbial growth and activity in soil making it difficult to compare results from different habitats. Q10 still is one of the most common ways to express temperature relationships. However, Q10 is not constant with temperature and will differ depending on the temperature interval used for the calculation. The use of the square root (Ratkowsky) relationship between microbial activity (A) and temperature below optimum temperature, √A = a × (T-T min ), is proposed as a simple and adequate model that allow for one descriptor, T min (a theoretical minimum temperature for growth and activity), to estimate correct Q10-values over the entire in situ temperature interval. The square root model can adequately describe both microbial growth and respiration, allowing for an easy determination of T min . Q10 for any temperature interval can then be calculated by Q10 = [(T + 10 - T min )/(T-T min )] 2 , where T is the lowest temperature in the Q10 comparison. T min also describes the temperature adaptation of the microbial community. An envelope of T min covering most natural soil habitats varying between -15°C (cold habitats like Antarctica/Arctic) to 0°C (tropical habitats like rain forests and deserts) is suggested, with an 0.3°C increase in T min per 1°C increase in mean annual temperature. It is shown that the main difference between common temperature relationships used in global models is differences in the assumed temperature adaptation of the soil microbial community. The use of the square root equation will allow for one descriptor, T min , determining the temperature response of soil microorganisms, and at the same time allow for comparing temperature sensitivity of microbial activity between habitats, including future projections. © 2018 John Wiley & Sons Ltd.

Perceived sports competence mediates the relationship between childhood motor skill proficiency and adolescent physical activity and fitness: a longitudinal assessment

PubMed Central

Barnett, Lisa M; Morgan, Philip J; van Beurden, Eric; Beard, John R

2008-01-01

Background The purpose of this paper was to investigate whether perceived sports competence mediates the relationship between childhood motor skill proficiency and subsequent adolescent physical activity and fitness. Methods In 2000, children's motor skill proficiency was assessed as part of a school-based physical activity intervention. In 2006/07, participants were followed up as part of the Physical Activity and Skills Study and completed assessments for perceived sports competence (Physical Self-Perception Profile), physical activity (Adolescent Physical Activity Recall Questionnaire) and cardiorespiratory fitness (Multistage Fitness Test). Structural equation modelling techniques were used to determine whether perceived sports competence mediated between childhood object control skill proficiency (composite score of kick, catch and overhand throw), and subsequent adolescent self-reported time in moderate-to-vigorous physical activity and cardiorespiratory fitness. Results Of 928 original intervention participants, 481 were located in 28 schools and 276 (57%) were assessed with at least one follow-up measure. Slightly more than half were female (52.4%) with a mean age of 16.4 years (range 14.2 to 18.3 yrs). Relevant assessments were completed by 250 (90.6%) students for the Physical Activity Model and 227 (82.3%) for the Fitness Model. Both hypothesised mediation models had a good fit to the observed data, with the Physical Activity Model accounting for 18% (R2 = 0.18) of physical activity variance and the Fitness Model accounting for 30% (R2 = 0.30) of fitness variance. Sex did not act as a moderator in either model. Conclusion Developing a high perceived sports competence through object control skill development in childhood is important for both boys and girls in determining adolescent physical activity participation and fitness. Our findings highlight the need for interventions to target and improve the perceived sports competence of youth. PMID:18687148

Effects of current physical activity on affective response to exercise: physical and social-cognitive mechanisms.

PubMed

Magnan, Renee E; Kwan, Bethany M; Bryan, Angela D

2013-01-01

Affective responses during exercise are often important determinants of exercise initiation and maintenance. Current physical activity may be one individual difference that is associated with the degree to which individuals have positive (or negative) affective experiences during exercise. The objective of this study was to explore physical and cognitive explanations of the relationship between current activity status (more versus less active) and affective response during a 30-minute bout of moderate-intensity exercise. Participants reported their current level of physical activity, exercise self-efficacy and affect during a 30-minute bout of moderate-intensity exercise. More active individuals experienced higher levels of positive affect and tranquillity and lower levels of negative affect and fatigue during exercise. Multivariate models for each affective state indicated separate processes through which physical activity may be associated with changes in affect during exercise. These models indicate that affect experienced during physical activity is related to the current activity level and these relationships can be partially explained by the physical and cognitive factors explored in this study. Recommendations for future research to elucidate whether positive affective response to physical activity improves as a function of becoming more active over time are discussed.

ANXIETY AND ATTACHMENT TO THE MOTHER IN PRESCHOOLERS RECEIVING PSYCHIATRIC CARE: THE FATHER-CHILD ACTIVATION RELATIONSHIP AS A PROTECTIVE FACTOR.

PubMed

Gaumon, Sébastien; Paquette, Daniel; Cyr, Chantal; Émond-Nakamura, Mutsuko; St-André, Martin

2016-07-01

This 49-family study is the first to explore the father-child relationship in a clinical population of preschoolers (at a tertiary care child psychiatry clinic) and to examine its relation to child anxiety and attachment to the mother. A moderation model of the father-child activation relationship on the relation between attachment to the mother and child anxiety was tested and discussed. Analyses confirmed the expected independence between mother-child attachment and father-child activation as well as the association between mother-child attachment and anxiety. The highest levels of anxiety were found in insecure children, and more specifically, in insecure-ambivalent children and insecure disorganized-controlling children of the caregiving subtype. Hypotheses regarding the relation between anxiety and activation were only partially confirmed. Finally, the activation relationship with the father was shown to have a moderating effect on the relation between attachment to the mother and child anxiety; activation by the father may be considered either a protective or a risk factor. Results for this clinical population of young children are discussed in the light of attachment theory and activation relationship theory. The study's findings have the potential to contribute to the development of preventative, diagnostic, and intervention programs that take both parental figures into account. © 2016 Michigan Association for Infant Mental Health.

Bio-mimicking galactose oxidase and hemocyanin, two dioxygen-processing copper proteins.

PubMed

Gamez, Patrick; Koval, Iryna A; Reedijk, Jan

2004-12-21

The modelling of the active sites of metalloproteins is one of the most challenging tasks in bio-inorganic chemistry. Copper proteins form part of this stimulating field of research as copper enzymes are mainly involved in oxidation bio-reactions. Thus, the understanding of the structure-function relationship of their active sites will allow the design of effective and environmental friendly oxidation catalysts. This perspective illustrates some outstanding structural and functional synthetic models of the active site of copper proteins, with special attention given to models of galactose oxidase and hemocyanin.

The Impact of Smoking in Adolescence on Early Adult Anxiety Symptoms and the Relationship between Infant Vulnerability Factors for Anxiety and Early Adult Anxiety Symptoms: The TOPP Study

PubMed Central

Moylan, Steven; Gustavson, Kristin; Karevold, Evalill; Øverland, Simon; Jacka, Felice N.; Pasco, Julie A.; Berk, Michael

2013-01-01

Cigarette smoking is increased in people with trait anxiety and anxiety disorders, however no longitudinal data exist illuminating whether smoking in adolescence can influence the developmental trajectory of anxiety symptoms from early vulnerability in infancy to adult anxiety expression. Using The Tracing Opportunities and Problems in Childhood and Adolescence (TOPP) Study, a community-based cohort of children and adolescents from Norway who were observed from the age of 18months to age 18–19years, we explored the relationship between adolescent smoking, early vulnerability for anxiety in infancy (e.g. shyness, internalizing behaviors, emotional temperaments) and reported early adult anxiety. Structural equation modeling demonstrated that adolescent active smoking was positively associated with increased early adulthood anxiety (β = 0.17, p<0.05), after controlling for maternal education (proxy for socioeconomic status). Adolescent anxiety did not predict early adult smoking. Adolescent active smoking was a significant effect modifier in the relationship between some infant vulnerability factors and later anxiety; smoking during adolescence moderated the relationship between infant internalizing behaviors (total sample: active smokers: β = 0.85,p<0.01, non-active smokers: ns) and highly emotional temperament (total sample: active smokers: β = 0.55,p<0.01,non-active smokers: ns), but not shyness, and anxiety in early adulthood. The results support a model where smoking acts as an exogenous risk factor in the development of anxiety, and smoking may alter the developmental trajectory of anxiety from infant vulnerability to early adult anxiety symptom expression. Although alternative non-mutually exclusive models may explain these findings, the results suggest that adolescent smoking may be a risk factor for adult anxiety, potentially by influencing anxiety developmental trajectories. Given the known adverse health effects of cigarette smoking and significant health burden imposed by anxiety disorders, this study supports the importance of smoking prevention and cessation programs targeting children and adolescence. PMID:23696803

TOWARDS REFINED USE OF TOXICITY DATA IN STATISTICALLY BASED SAR MODELS FOR DEVELOPMENTAL TOXICITY.

EPA Science Inventory

In 2003, an International Life Sciences Institute (ILSI) Working Group examined the potential of statistically based structure-activity relationship (SAR) models for use in screening environmental contaminants for possible developmental toxicants.

VERIFICATION AND VALIDATION OF THE SPARC MODEL

EPA Science Inventory

Mathematical models for predicting the transport and fate of pollutants in the environment require reactivity parameter values--that is, the physical and chemical constants that govern reactivity. Although empirical structure-activity relationships that allow estimation of some ...

A Way Forward Commentary

EPA Science Inventory

Models for predicting adverse outcomes can help reduce and focus animal testing with new and existing chemicals. This short "thought starter" describes how quantitative-structure activity relationship and systems biology models can be used to help define toxicity pathways and li...

Task allocation model for minimization of completion time in distributed computer systems

NASA Astrophysics Data System (ADS)

Wang, Jai-Ping; Steidley, Carl W.

1993-08-01

A task in a distributed computing system consists of a set of related modules. Each of the modules will execute on one of the processors of the system and communicate with some other modules. In addition, precedence relationships may exist among the modules. Task allocation is an essential activity in distributed-software design. This activity is of importance to all phases of the development of a distributed system. This paper establishes task completion-time models and task allocation models for minimizing task completion time. Current work in this area is either at the experimental level or without the consideration of precedence relationships among modules. The development of mathematical models for the computation of task completion time and task allocation will benefit many real-time computer applications such as radar systems, navigation systems, industrial process control systems, image processing systems, and artificial intelligence oriented systems.

Objective vs. self-reported physical activity and sedentary time: effects of measurement method on relationships with risk biomarkers.

PubMed

Celis-Morales, Carlos A; Perez-Bravo, Francisco; Ibañez, Luis; Salas, Carlos; Bailey, Mark E S; Gill, Jason M R

2012-01-01

Imprecise measurement of physical activity variables might attenuate estimates of the beneficial effects of activity on health-related outcomes. We aimed to compare the cardiometabolic risk factor dose-response relationships for physical activity and sedentary behaviour between accelerometer- and questionnaire-based activity measures. Physical activity and sedentary behaviour were assessed in 317 adults by 7-day accelerometry and International Physical Activity Questionnaire (IPAQ). Fasting blood was taken to determine insulin, glucose, triglyceride and total, LDL and HDL cholesterol concentrations and homeostasis model-estimated insulin resistance (HOMA(IR)). Waist circumference, BMI, body fat percentage and blood pressure were also measured. For both accelerometer-derived sedentary time (<100 counts.min(-1)) and IPAQ-reported sitting time significant positive (negative for HDL cholesterol) relationships were observed with all measured risk factors--i.e. increased sedentary behaviour was associated with increased risk (all p ≤ 0.01). However, for HOMA(IR) and insulin the regression coefficients were >50% lower for the IPAQ-reported compared to the accelerometer-derived measure (p<0.0001 for both interactions). The relationships for moderate-to-vigorous physical activity (MVPA) and risk factors were less strong than those observed for sedentary behaviours, but significant negative relationships were observed for both accelerometer and IPAQ MVPA measures with glucose, and insulin and HOMA(IR) values (all p<0.05). For accelerometer-derived MVPA only, additional negative relationships were seen with triglyceride, total cholesterol and LDL cholesterol concentrations, BMI, waist circumference and percentage body fat, and a positive relationship was evident with HDL cholesterol (p = 0.0002). Regression coefficients for HOMA(IR), insulin and triglyceride were 43-50% lower for the IPAQ-reported compared to the accelerometer-derived MVPA measure (all p≤0.01). Using the IPAQ to determine sitting time and MVPA reveals some, but not all, relationships between these activity measures and metabolic and vascular disease risk factors. Using this self-report method to quantify activity can therefore underestimate the strength of some relationships with risk factors.

Detailed Anatomical and Electrophysiological Models of Human Atria and Torso for the Simulation of Atrial Activation

PubMed Central

Ferrer, Ana; Sebastián, Rafael; Sánchez-Quintana, Damián; Rodríguez, José F.; Godoy, Eduardo J.; Martínez, Laura; Saiz, Javier

2015-01-01

Atrial arrhythmias, and specifically atrial fibrillation (AF), induce rapid and irregular activation patterns that appear on the torso surface as abnormal P-waves in electrocardiograms and body surface potential maps (BSPM). In recent years both P-waves and the BSPM have been used to identify the mechanisms underlying AF, such as localizing ectopic foci or high-frequency rotors. However, the relationship between the activation of the different areas of the atria and the characteristics of the BSPM and P-wave signals are still far from being completely understood. In this work we developed a multi-scale framework, which combines a highly-detailed 3D atrial model and a torso model to study the relationship between atrial activation and surface signals in sinus rhythm. Using this multi scale model, it was revealed that the best places for recording P-waves are the frontal upper right and the frontal and rear left quadrants of the torso. Our results also suggest that only nine regions (of the twenty-one structures in which the atrial surface was divided) make a significant contribution to the BSPM and determine the main P-wave characteristics. PMID:26523732

Departmental Contexts and Faculty Research Activity in Norway

ERIC Educational Resources Information Center

Smeby, Jens-Christian; Try, Sverre

2005-01-01

The aim of the paper is to examine the relationship between departmental attributes and university faculty research activity. Since individual and departmental factors are highly interrelated, individual attributes are included in a hierarchical linear model taking into consideration the nested structure of the data. Research activity is measured…

Space station functional relationships analysis

NASA Technical Reports Server (NTRS)

Tullis, Thomas S.; Bied, Barbra R.

1988-01-01

A systems engineering process is developed to assist Space Station designers to understand the underlying operational system of the facility so that it can be physically arranged and configured to support crew productivity. The study analyzes the operational system proposed for the Space Station in terms of mission functions, crew activities, and functional relationships in order to develop a quantitative model for evaluation of interior layouts, configuration, and traffic analysis for any Station configuration. Development of the model involved identification of crew functions, required support equipment, criteria of assessing functional relationships, and tools for analyzing functional relationship matrices, as well as analyses of crew transition frequency, sequential dependencies, support equipment requirements, potential for noise interference, need for privacy, and overall compatability of functions. The model can be used for analyzing crew functions for the Initial Operating Capability of the Station and for detecting relationships among these functions. Note: This process (FRA) was used during Phase B design studies to test optional layouts of the Space Station habitat module. The process is now being automated as a computer model for use in layout testing of the Space Station laboratory modules during Phase C.

Advantages and limitations of classic and 3D QSAR approaches in nano-QSAR studies based on biological activity of fullerene derivatives

DOE PAGES

Jagiello, Karolina; Grzonkowska, Monika; Swirog, Marta; ...

2016-08-29

In this contribution, the advantages and limitations of two computational techniques that can be used for the investigation of nanoparticles activity and toxicity: classic nano-QSAR (Quantitative Structure–Activity Relationships employed for nanomaterials) and 3D nano-QSAR (three-dimensional Quantitative Structure–Activity Relationships, such us Comparative Molecular Field Analysis, CoMFA/Comparative Molecular Similarity Indices Analysis, CoMSIA analysis employed for nanomaterials) have been briefly summarized. Both approaches were compared according to the selected criteria, including: efficiency, type of experimental data, class of nanomaterials, time required for calculations and computational cost, difficulties in the interpretation. Taking into account the advantages and limitations of each method, we provide themore » recommendations for nano-QSAR modellers and QSAR model users to be able to determine a proper and efficient methodology to investigate biological activity of nanoparticles in order to describe the underlying interactions in the most reliable and useful manner.« less

Multi-criteria optimization for ultrasonic-assisted extraction of antioxidants from Pericarpium Citri Reticulatae using response surface methodology, an activity-based approach.

PubMed

Zeng, Shanshan; Wang, Lu; Zhang, Lei; Qu, Haibin; Gong, Xingchu

2013-06-01

An activity-based approach to optimize the ultrasonic-assisted extraction of antioxidants from Pericarpium Citri Reticulatae (Chenpi in Chinese) was developed. Response surface optimization based on a quantitative composition-activity relationship model showed the relationships among product chemical composition, antioxidant activity of extract, and parameters of extraction process. Three parameters of ultrasonic-assisted extraction, including the ethanol/water ratio, Chenpi amount, and alkaline amount, were investigated to give optimum extraction conditions for antioxidants of Chenpi: ethanol/water 70:30 v/v, Chenpi amount of 10 g, and alkaline amount of 28 mg. The experimental antioxidant yield under the optimum conditions was found to be 196.5 mg/g Chenpi, and the antioxidant activity was 2023.8 μmol Trolox equivalents/g of the Chenpi powder. The results agreed well with the second-order polynomial regression model. This presented approach promised great application potentials in both food and pharmaceutical industries. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advantages and limitations of classic and 3D QSAR approaches in nano-QSAR studies based on biological activity of fullerene derivatives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jagiello, Karolina; Grzonkowska, Monika; Swirog, Marta

In this contribution, the advantages and limitations of two computational techniques that can be used for the investigation of nanoparticles activity and toxicity: classic nano-QSAR (Quantitative Structure–Activity Relationships employed for nanomaterials) and 3D nano-QSAR (three-dimensional Quantitative Structure–Activity Relationships, such us Comparative Molecular Field Analysis, CoMFA/Comparative Molecular Similarity Indices Analysis, CoMSIA analysis employed for nanomaterials) have been briefly summarized. Both approaches were compared according to the selected criteria, including: efficiency, type of experimental data, class of nanomaterials, time required for calculations and computational cost, difficulties in the interpretation. Taking into account the advantages and limitations of each method, we provide themore » recommendations for nano-QSAR modellers and QSAR model users to be able to determine a proper and efficient methodology to investigate biological activity of nanoparticles in order to describe the underlying interactions in the most reliable and useful manner.« less

Longitudinal relationships between resources, motivation, and functioning.

PubMed

Hess, Thomas M; Emery, Lisa; Neupert, Shevaun D

2012-05-01

We investigated how fluctuations and linear changes in health and cognitive resources influence the motivation to engage in complex cognitive activity and the extent to which motivation mediated the relationship between changing resources and cognitively demanding activities. Longitudinal data from 332 adults aged 20-85 years were examined. Motivation was assessed using a composite of Need for Cognition and Personal Need for Structure and additional measures of health, sensory functioning, cognitive ability, and self-reported activity engagement. Multilevel modeling revealed that age-typical changes in health, sensory functions, and ability were associated with changes in motivation, with the impact of declining health on motivation being particularly strong in older adulthood. Changes in motivation, in turn, predicted involvement in cognitive and social activities as well as changes in cognitive ability. Finally, motivation was observed to partially mediate the relationship between changes in resources and cognitively demanding activities. Our results suggest that motivation may play an important role in determining the course of cognitive change and involvement in cognitively demanding everyday activities in adulthood.

Exploring Third-Grade Student Model-Based Explanations about Plant Relationships within an Ecosystem

NASA Astrophysics Data System (ADS)

Zangori, Laura; Forbes, Cory T.

2015-12-01

Elementary students should have opportunities to develop scientific models to reason and build understanding about how and why plants depend on relationships within an ecosystem for growth and survival. However, scientific modeling practices are rarely included within elementary science learning environments and disciplinary content is often treated as discrete pieces separate from scientific practice. Elementary students have few, if any, opportunities to reason about how individual organisms, such as plants, hold critical relationships with their surrounding environment. The purpose of this design-based research study is to build a learning performance to identify and explore the third-grade students' baseline understanding of and their reasoning about plant-ecosystem relationships when engaged in the practices of modeling. The developed learning performance integrated scientific content and core scientific activity to identify and measure how students build knowledge about the role of plants in ecosystems through the practices of modeling. Our findings indicate that the third-grade students' ideas about plant growth include abiotic and biotic relationships. Further, they used their models to reason about how and why these relationships were necessary to maintain plant stasis. However, while the majority of the third-grade students were able to identify and reason about plant-abiotic relationships, a much smaller group reasoned about plant-abiotic-animal relationships. Implications from the study suggest that modeling serves as a tool to support elementary students in reasoning about system relationships, but they require greater curricular and instructional support in conceptualizing how and why ecosystem relationships are necessary for plant growth and development. This paper is based on data from a doctoral dissertation. An earlier version of this paper was presented at the 2015 international conference for the National Association for Research in Science Teaching (NARST) Zangori, L., & Forbes, C. T. (2015). Exploring 3rd-grade student model-based explanations about plant process interactions within the hydrosphere Portions of this paper are based on that work.

Protective activity of (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol analogues against diisopropylfluorophosphate neurotoxicity: preliminary structure-activity relationship and pharmacophore modeling.

PubMed

Eterović, Vesna A; Del Valle-Rodriguez, Angelie; Pérez, Dinely; Carrasco, Marimée; Khanfar, Mohammad A; El Sayed, Khalid A; Ferchmin, Pedro A

2013-08-01

Diisopropylfluorophosphate (DFP) is an organophosphorous insecticide used as a surrogate for the more toxic chemical warfare nerve agent sarin. DFP produces neurotoxicity in vivo and irreversibly decreases the area of population spikes recorded from the CA1 region of acute hippocampal slices. (1S,2E,4R,6R,7E,11E)-2,7,11-Cembratriene-4,6-diol (1) is a neuroprotective natural cembranoid that reverses DFP-induced damage both in vivo and in the hippocampal slice. Cembranoid 1 acts by noncompetitive inhibition of the α7 nicotinic acetylcholine receptor. This study aims at establishing a preliminary structure-activity relationship to define the neuroprotective cembranoid pharmacophores using the hippocampal slice assay and pharmacophore modeling. Fourteen natural, semisynthetic, or biocatalytic cembranoid analogues 2-15 related to 1 were tested for their capacity to protect the population spikes from DFP-induced damage and intrinsic toxicity. Twelve cembranoids caused significant reversal of DFP toxicity; only 3 active analogues displayed minor intrinsic toxicity at 10 μM. The C-4 epimer of 1 (2) and the 4-O-methyl ether analogue of 1 (3), were totally devoid of neuroprotective activity. The results suggested a model for cembranoid binding where the hydrophobic ring surface binds to a hydrophobic (Hbic) patch on the receptor molecule and an electronegative atom (oxygen or sulfur) in proper spatial relationship to the ring surface interacts with an electropositive group in the receptor binding site. A pharmacophore model consisting of 1 hydrogen bond acceptor (HBA), 2 Hbic, and 10 exclusion spheres was established using HipHop-REFINE and supported the above mentioned pharmacophoric hypothesis. Copyright © 2013 Elsevier Ltd. All rights reserved.

On the controls of deep convection and lightning in the Amazon

NASA Astrophysics Data System (ADS)

Albrecht, R. I.; Giangrande, S. E.; Wang, D.; Morales, C. A.; Pereira, R. F. O.; Machado, L.; Silva Dias, M. A. F.

2017-12-01

Local observations and remote sensing have been extensively used to unravel cloud distribution and life cycle but yet their representativeness in cloud resolve models (CRMs) and global climate models (GCMs) are still very poor. In addition, the complex cloud-aerosol-precipitation interactions (CAPI), as well as thermodynamics, dynamics and large scale controls on convection have been the focus of many studies in the last two decades but still no final answer has been reached on the overall impacts of these interactions and controls on clouds, especially on deep convection. To understand the environmental and CAPI controls of deep convection, cloud electrification and lightning activity in the pristine region of Amazon basin, in this study we use long term satellite and field campaign measurements to depict the characteristics of deep convection and the relationships between lightning and convective fluxes in this region. Precipitation and lightning activity from the Tropical Rainfall Measuring Mission (TRMM) satellite are combined with estimates of aerosol concentrations and reanalysis data to delineate the overall controls on thunderstorms. A more detailed analysis is obtained studying these controls on the relationship between lightning activity and convective mass fluxes using radar wind profiler and 3D total lightning during GoAmazon 2014/15 field campaign. We find evidences that the large scale conditions control the distribution of the precipitation, with widespread and more frequent mass fluxes of moderate intensity during the wet season, resulting in less vigorous convection and lower lightning activity. Under higher convective available potential energy, lightning is enhanced in polluted and background aerosol conditions. The relationships found in this study can be used in model parameterizations and ensemble evaluations of both lightning activity and lightning NOx from seasonal forecasting to climate projections and in a broader sense to Earth Climate System Modeling.

Evaluation of analgesic and anti-inflammatory activities of Rubia cordifolia L. by spectrum-effect relationships.

PubMed

Shen, Cai-Hong; Liu, Cui-Ting; Song, Xiao-Juan; Zeng, Wei-Ya; Lu, Xiao-Ying; Zheng, Zuo-Liang; Jie-Pan; Zhan, Ruo-Ting; Ping-Yan

2018-07-15

The objective of the current work was to evaluate the spectrum-effect relationships between high-performance liquid chromatography fingerprints and analgesic and anti-inflammatory effects of Rubia cordifolia L. extract (RCE), and to identify active components of RCE. Chemical fingerprints of ten batches of RC from various sources were obtained by HPLC, and similarity and hierarchical clustering analyses were carried out. Pharmacodynamic assays were performed in adjuvant-induced arthritis rat model to assess the analgesic and anti-inflammatory properties of RCE. The spectrum-effect relationships between chemical fingerprints and the analgesic and anti-inflammatory effects of RCE were established by gray correlation analysis. UPLC-ESI-MS was used to identify the structures of potential active components, by reference standards comparison. The results showed that a close correlation existed between chemical fingerprints with analgesic and anti-inflammatory activities, and alizarin, 6-hydroxyrubiadin, purpurin and rubiadin might be the active constituents of RCE. In addition, RCE attenuated pathological changes in adjuvant-induced arthritis. The current findings provide a strong basis for combining chemical fingerprints with analgesic and anti-inflammatory activities in assessing the spectrum-effect relationships of RCE. Copyright © 2018. Published by Elsevier B.V.

Change in physical education motivation and physical activity behavior during middle school.

PubMed

Cox, Anne E; Smith, Alan L; Williams, Lavon

2008-11-01

To test a mediational model of the relationships among motivation-related variables in middle-school physical education and leisure-time physical activity behavior. Sixth- and seventh-grade physical education students from five middle schools in the midwest United States completed a survey containing measures of study variables on two occasions, 1 year apart. Motivation-related constructs positively predicted leisure-time physical activity behavior. Enjoyment of activities in physical education and physical activity during class mediated the relationship between self-determined motivation in physical education and leisure-time physical activity. Perceived competence, autonomy, and relatedness were important antecedent variables in the model, with autonomy and relatedness showing less stability over time and positively predicting self-determined motivation. Students' leisure-time physical activity is linked to motivation-related experiences in physical education. Perceptions of competence, autonomy, and relatedness, self-determined motivation, enjoyment, and physical activity in the physical education setting directly or indirectly predict leisure-time physical activity. The associations suggest that more adaptive motivation corresponds to transfer of behavior across contexts. Also, the findings suggest that the efficacy of school-based physical activity interventions, within and outside of school, is linked to the degree of support for students' self-determined motivation.

Phototransduction early steps model based on Beer-Lambert optical law.

PubMed

Salido, Ezequiel M; Servalli, Leonardo N; Gomez, Juan Carlos; Verrastro, Claudio

2017-02-01

The amount of available rhodopsin on the photoreceptor outer segment and its change over time is not considered in classic models of phototransduction. Thus, those models do not take into account the absorptance variation of the outer segment under different brightness conditions. The relationship between the light absorbed by a medium and its absorptance is well described by the Beer-Lambert law. This newly proposed model implements the absorptance variation phenomenon in a set of equations that admit photons per second as input and results in active rhodopsins per second as output. This study compares the classic model of phototransduction developed by Forti et al. (1989) to this new model by using different light stimuli to measure active rhodopsin and photocurrent. The results show a linear relationship between light stimulus and active rhodopsin in the Forti model and an exponential saturation in the new model. Further, photocurrent values have shown that the new model behaves equivalently to the experimental and theoretical data as published by Forti in dark-adapted rods, but fits significantly better under light-adapted conditions. The new model successfully introduced a physics optical law to the standard model of phototransduction adding a new processing layer that had not been mathematically implemented before. In addition, it describes the physiological concept of saturation and delivers outputs in concordance to input magnitudes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Parent-child relationships of boys in different offending trajectories. A developmental perspective

PubMed Central

Keijsers, Loes; Loeber, Rolf; Branje, Susan; Meeus, Wim

2012-01-01

Background This study tested the theoretical assumption that transformations of parent-child relationships in late childhood and adolescence would differ for boys following different offending trajectories. Methods Using longitudinal multiinformant data of 503 boys (ages 7–19), we conducted Growth Mixture Modeling to extract offending trajectories. Developmental changes in child reports of parent-child joint activities and relationship quality were examined using Latent Growth Curves. Results Five offending trajectories were found: non-offenders, moderate childhood offenders, adolescent-limited offenders, serious childhood offenders, and serious persistent offenders. Non-offenders reported high and stable levels of relationship quality between age 10 and 16. Adolescent-limited offenders reported a similarly high relationship quality as non-offenders at ages 7 and 10, but a lower and decreasing relationship quality in adolescence. Compared with non-offenders, serious persistent offenders reported poorer parent-child relationship quality at all ages, and a decreasing relationship quality in adolescence. Serious persistent offenders and adolescent-limited offenders reported similar levels and changes in parent-child relationship quality in adolescence. Although serious persistent offenders reported fewer joint activities at age 10 and 13 than non-offenders, a similar linear decrease in joint activities in early to middle adolescence was found for boys in each trajectory. Conclusion Developmental changes in parent-child relationship quality differ for different types of offenders. This finding has scientific and practical implications. PMID:22816682

Comparison of three approaches to model grapevine organogenesis in conditions of fluctuating temperature, solar radiation and soil water content.

PubMed

Pallas, B; Loi, C; Christophe, A; Cournède, P H; Lecoeur, J

2011-04-01

There is increasing interest in the development of plant growth models representing the complex system of interactions between the different determinants of plant development. These approaches are particularly relevant for grapevine organogenesis, which is a highly plastic process dependent on temperature, solar radiation, soil water deficit and trophic competition. The extent to which three plant growth models were able to deal with the observed plasticity of axis organogenesis was assessed. In the first model, axis organogenesis was dependent solely on temperature, through thermal time. In the second model, axis organogenesis was modelled through functional relationships linking meristem activity and trophic competition. In the last model, the rate of phytomer appearence on each axis was modelled as a function of both the trophic status of the plant and the direct effect of soil water content on potential meristem activity. The model including relationships between trophic competition and meristem behaviour involved a decrease in the root mean squared error (RMSE) for the simulations of organogenesis by a factor nine compared with the thermal time-based model. Compared with the model in which axis organogenesis was driven only by trophic competition, the implementation of relationships between water deficit and meristem behaviour improved organogenesis simulation results, resulting in a three times divided RMSE. The resulting model can be seen as a first attempt to build a comprehensive complete plant growth model simulating the development of the whole plant in fluctuating conditions of temperature, solar radiation and soil water content. We propose a new hypothesis concerning the effects of the different determinants of axis organogenesis. The rate of phytomer appearance according to thermal time was strongly affected by the plant trophic status and soil water deficit. Furthermore, the decrease in meristem activity when soil water is depleted does not result from source/sink imbalances.

Rational design, synthesis, biologic evaluation, and structure-activity relationship studies of novel 1-indanone alpha(1)-adrenoceptor antagonists.

PubMed

Li, Minyong; Xia, Lin

2007-11-01

In the present report, a novel series of 1-indanone alpha(1)-adrenoceptor antagonists were designed and synthesized based on 3D-pharmacophore model. Their in vitro alpha(1)-adrenoceptor antagonistic assay showed that three compounds (2a, 2m, and 2o) had similar or improved alpha(1)-adrenoceptor antagonistic activities relative to the positive control prazosin. Based on these results, a three-dimensional quantitative structure-activity relationship study was performed using a Self-Organizing Molecular Field Analysis method to provide insight for the future development of alpha(1)-adrenoceptor antagonists.

Sedentary Activity and Body Composition of Middle School Girls: The Trial of Activity for Adolescent Girls

ERIC Educational Resources Information Center

Pratt, Charlotte; Webber, Larry S.; Baggett, Chris D.; Ward, Dianne; Pate, Russell R.; Murray, David; Lohman, Timothy; Lytle, Leslie; Elder, John P.

2008-01-01

This study describes the relationships between sedentary activity and body composition in 1,458 sixth-grade girls from 36 middle schools across the United States. Multivariate associations between sedentary activity and body composition were examined with regression analyses using general linear mixed models. Mean age, body mass index, and…

An Examination of the Relationship between Passion and Subjective Well-Being in Older Adults

ERIC Educational Resources Information Center

Rousseau, Francois L.; Vallerand, Robert J.

2008-01-01

Activity engagement has long been linked to improved subjective well-being (SWB) in old age. However, recent studies testing Vallerand et al.'s (2003) Dualistic Model of Passion suggest that the type of passionate activity that underlies activity engagement might influence the extent to which individuals benefit from an active lifestyle. In the…

Activity interference and noise annoyance

NASA Astrophysics Data System (ADS)

Hall, F. L.; Taylor, S. M.; Birnie, S. E.

1985-11-01

Debate continues over differences in the dose-response functions used to predict the annoyance at different sources of transportation noise. This debate reflects the lack of an accepted model of noise annoyance in residential communities. In this paper a model is proposed which is focussed on activity interference as a central component mediating the relationship between noise exposure and annoyance. This model represents a departure from earlier models in two important respects. First, single event noise levels (e.g., maximum levels, sound exposure level) constitute the noise exposure variables in place of long-term energy equivalent measures (e.g., 24-hour Leq or Ldn). Second, the relationships within the model are expressed as probabilistic rather than deterministic equations. The model has been tested by using acoustical and social survey data collected at 57 sites in the Toronto region exposed to aircraft, road traffic or train noise. Logit analysis was used to estimate two sets of equations. The first predicts the probability of activity interference as a function of event noise level. Four types of interference are included: indoor speech, outdoor speech, difficulty getting to sleep and awakening. The second set predicts the probability of annoyance as a function of the combination of activity interferences. From the first set of equations, it was possible to estimate a function for indoor speech interference only. In this case, the maximum event level was the strongest predictor. The lack of significant results for the other types of interference is explained by the limitations of the data. The same function predicts indoor speech interference for all three sources—road, rail and aircraft noise. The results for the second set of equations show strong relationships between activity interference and the probability of annoyance. Again, the parameters of the logit equations are similar for the three sources. A trial application of the model predicts a higher probability of annoyance for aircraft than for road traffic situations with the same 24-hour Leq. This result suggests that the model may account for previously reported source differences in annoyance.

Using avian radar to examine relationships among avian activity, bird strikes, and meteorological factors

USGS Publications Warehouse

Coates, Peter S.; Casazza, Michael L.; Halstead, Brian J.; Fleskes, Joseph P.; Laughlin, James A.

2011-01-01

Radar systems designed to detect avian activity at airfields are useful in understanding factors that influence the risk of bird and aircraft collisions (bird strikes). We used an avian radar system to measure avian activity at Beale Air Force Base, California, USA, during 2008 and 2009. We conducted a 2-part analysis to examine relationships among avian activity, bird strikes, and meteorological and time-dependent factors. We found that avian activity around the airfield was greater at times when bird strikes occurred than on average using a permutation resampling technique. Second, we developed generalized linear mixed models of an avian activity index (AAI). Variation in AAI was first explained by seasons that were based on average migration dates of birds at the study area. We then modeled AAI by those seasons to further explain variation by meteorological factors and daily light levels within a 24-hour period. In general, avian activity increased with decreased temperature, wind, visibility, precipitation, and increased humidity and cloud cover. These effects differed by season. For example, during the spring bird migration period, most avian activity occurred before sunrise at twilight hours on clear days with low winds, whereas during fall migration, substantial activity occurred after sunrise, and birds generally were more active at lower temperatures. We report parameter estimates (i.e., constants and coefficients) averaged across models and a relatively simple calculation for safety officers and wildlife managers to predict AAI and the relative risk of bird strike based on time, date, and meteorological values. We validated model predictability and assessed model fit. These analyses will be useful for general inference of avian activity and risk assessment efforts. Further investigation and ongoing data collection will refine these inference models and improve our understanding of factors that influence avian activity, which is necessary to inform management decisions aimed at reducing risk of bird strikes.

Application of Quantitative Structure–Activity Relationship Models of 5-HT1A Receptor Binding to Virtual Screening Identifies Novel and Potent 5-HT1A Ligands

PubMed Central

2015-01-01

The 5-hydroxytryptamine 1A (5-HT1A) serotonin receptor has been an attractive target for treating mood and anxiety disorders such as schizophrenia. We have developed binary classification quantitative structure–activity relationship (QSAR) models of 5-HT1A receptor binding activity using data retrieved from the PDSP Ki database. The prediction accuracy of these models was estimated by external 5-fold cross-validation as well as using an additional validation set comprising 66 structurally distinct compounds from the World of Molecular Bioactivity database. These validated models were then used to mine three major types of chemical screening libraries, i.e., drug-like libraries, GPCR targeted libraries, and diversity libraries, to identify novel computational hits. The five best hits from each class of libraries were chosen for further experimental testing in radioligand binding assays, and nine of the 15 hits were confirmed to be active experimentally with binding affinity better than 10 μM. The most active compound, Lysergol, from the diversity library showed very high binding affinity (Ki) of 2.3 nM against 5-HT1A receptor. The novel 5-HT1A actives identified with the QSAR-based virtual screening approach could be potentially developed as novel anxiolytics or potential antischizophrenic drugs. PMID:24410373

Novel approaches to determine contractile function of the isolated adult zebrafish ventricular cardiac myocyte.

PubMed

Dvornikov, Alexey V; Dewan, Sukriti; Alekhina, Olga V; Pickett, F Bryan; de Tombe, Pieter P

2014-05-01

The zebrafish (Danio rerio) has been used extensively in cardiovascular biology, but mainly in the study of heart development. The relative ease of its genetic manipulation may indicate the suitability of this species as a cost-effective model system for the study of cardiac contractile biology. However, whether the zebrafish heart is an appropriate model system for investigations pertaining to mammalian cardiac contractile structure-function relationships remains to be resolved. Myocytes were isolated from adult zebrafish hearts by enzymatic digestion, attached to carbon rods, and twitch force and intracellular Ca(2+) were measured. We observed the modulation of twitch force, but not of intracellular Ca(2+), by both extracellular [Ca(2+)] and sarcomere length. In permeabilized cells/myofibrils, we found robust myofilament length-dependent activation. Moreover, modulation of myofilament activation-relaxation and force redevelopment kinetics by varied Ca(2+) activation levels resembled that found previously in mammalian myofilaments. We conclude that the zebrafish is a valid model system for the study of cardiac contractile structure-function relationships.

Sorafenib Dose Recommendation in Acute Myeloid Leukemia Based on Exposure-FLT3 Relationship.

PubMed

Liu, Tao; Ivaturi, Vijay; Sabato, Philip; Gobburu, Jogarao V S; Greer, Jacqueline M; Wright, John J; Smith, B Douglas; Pratz, Keith W; Rudek, Michelle A

2018-04-27

Sorafenib administered at the approved dose continuously is not tolerated long-term in patients with acute myeloid leukemia (AML). The purpose of this study was to optimize the dosing regimen by characterizing the sorafenib exposure-response relationship in patients with AML. A one-compartment model with a transit absorption compartment and enterohepatic recirculation described the exposure. The relationship between sorafenib exposure and target modulation of kinase targets (FMS-like tyrosine kinase 3 (FLT3)-ITD and extracellular signal-regulated kinase (ERK)) were described by an inhibitory maximum effect (E max ) model. Sorafenib could inhibit FLT3-ITD activity by 100% with an IC 50 of 69.3 ng/mL and ERK activity by 84% with an IC 50 of 85.7 ng/mL (both adjusted for metabolite potency). Different dosing regimens utilizing 200 or 400 mg at varying frequencies were simulated based on the exposure-response relationship. Simulations demonstrate that a 200 mg twice daily (b.i.d.) dosing regimen showed similar FLT3-ITD and ERK inhibitory activity compared with 400 mg b.i.d. and is recommended in further clinical trials in patients with AML. © 2018 The Authors. Clinical and Translational Science published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.

Online health consultation: examining uses of an interactive cancer communication tool by low-income women with breast cancer.

PubMed

Lu, Hsueh-Yi; Shaw, Bret R; Gustafson, David H

2011-07-01

To examine how psychosocial variables predicted use of an online health consultation service among low-income breast cancer patients and in turn how using this service affected these same psychosocial outcomes. This retrospective study included 231 recently diagnosed, low-income (at or below 250% of the federal poverty level) breast cancer patients provided a free computer with 16 weeks of access to the Internet-based 'Ask an Expert' service offered as part of the Comprehensive Health Enhancement Support System (CHESS) "Living with Breast Cancer" program. The use activity included a total of 502 messages submitted to the online health consultation service. The data included five psychosocial variables: information seeking, social support, health self efficacy, participation in health care, and doctor-patient relationship, were collected at both the pre-test and 16-week post-test after using the service. Correlation tests were conducted to examine the relationship between pre- and post-test, and use activity. A multiple regression model was formed for each of five psychosocial variables to examine how use activity of the consultation service was associated with various psychosocial measurements. In total, 865 distinct consulting queries from 502 messages were identified as measurement of patients' use activities (3.74 consulting queries per participant). Use activity had significant negative relationships with pre-test scores across all five psychosocial variables. The regression models found significant positive main effects (use activity) associated with three of these psychosocial variables: health self efficacy, participation in health care and doctor-patient relationship. Use activity of the online consultation service did not have significant relationships with the dependent variables of information seeking and perceived social support. Low-income breast cancer patients sought out information from an online cancer information expert. Patients with more negative perceptions at pre-test tended to use the service more. Greater use of the service was associated with improvement in patients' perception of health self-efficacy, participation in health care and doctor-patient relationship. Moreover, use of online health consultation appears to level the differences, narrowing the gaps between those who were worse and better off at pre-test. These findings suggest that online health consultation can serve as an effective complement to other resources, which help low-income, breast cancer patients feel more confident to participate more actively in their health care, become more actively involved in making decisions about their treatments and enhance the relationship with their doctors. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Neuronal synchrony and the relation between the blood-oxygen-level dependent response and the local field potential

PubMed Central

Nguyen, Mai; Winawer, Jonathan

2017-01-01

The most widespread measures of human brain activity are the blood-oxygen-level dependent (BOLD) signal and surface field potential. Prior studies report a variety of relationships between these signals. To develop an understanding of how to interpret these signals and the relationship between them, we developed a model of (a) neuronal population responses and (b) transformations from neuronal responses into the functional magnetic resonance imaging (fMRI) BOLD signal and electrocorticographic (ECoG) field potential. Rather than seeking a transformation between the two measures directly, this approach interprets each measure with respect to the underlying neuronal population responses. This model accounts for the relationship between BOLD and ECoG data from human visual cortex in V1, V2, and V3, with the model predictions and data matching in three ways: across stimuli, the BOLD amplitude and ECoG broadband power were positively correlated, the BOLD amplitude and alpha power (8–13 Hz) were negatively correlated, and the BOLD amplitude and narrowband gamma power (30–80 Hz) were uncorrelated. The two measures provide complementary information about human brain activity, and we infer that features of the field potential that are uncorrelated with BOLD arise largely from changes in synchrony, rather than level, of neuronal activity. PMID:28742093

Selection of appropriate training and validation set chemicals for modelling dermal permeability by U-optimal design.

PubMed

Xu, G; Hughes-Oliver, J M; Brooks, J D; Yeatts, J L; Baynes, R E

2013-01-01

Quantitative structure-activity relationship (QSAR) models are being used increasingly in skin permeation studies. The main idea of QSAR modelling is to quantify the relationship between biological activities and chemical properties, and thus to predict the activity of chemical solutes. As a key step, the selection of a representative and structurally diverse training set is critical to the prediction power of a QSAR model. Early QSAR models selected training sets in a subjective way and solutes in the training set were relatively homogenous. More recently, statistical methods such as D-optimal design or space-filling design have been applied but such methods are not always ideal. This paper describes a comprehensive procedure to select training sets from a large candidate set of 4534 solutes. A newly proposed 'Baynes' rule', which is a modification of Lipinski's 'rule of five', was used to screen out solutes that were not qualified for the study. U-optimality was used as the selection criterion. A principal component analysis showed that the selected training set was representative of the chemical space. Gas chromatograph amenability was verified. A model built using the training set was shown to have greater predictive power than a model built using a previous dataset [1].

Understanding the Hysteresis Loop Conundrum in Pharmacokinetic / Pharmacodynamic Relationships

PubMed Central

Louizos, Christopher; Yáñez, Jaime A.; Forrest, Laird; Davies, Neal M.

2015-01-01

Hysteresis loops are phenomena that sometimes are encountered in the analysis of pharmacokinetic and pharmacodynamic relationships spanning from pre-clinical to clinical studies. When hysteresis occurs it provides insight into the complexity of drug action and disposition that can be encountered. Hysteresis loops suggest that the relationship between drug concentration and the effect being measured is not a simple direct relationship, but may have an inherent time delay and disequilibrium, which may be the result of metabolites, the consequence of changes in pharmacodynamics or the use of a non-specific assay or may involve an indirect relationship. Counter-clockwise hysteresis has been generally defined as the process in which effect can increase with time for a given drug concentration, while in the case of clockwise hysteresis the measured effect decreases with time for a given drug concentration. Hysteresis loops can occur as a consequence of a number of different pharmacokinetic and pharmacodynamic mechanisms including tolerance, distributional delay, feedback regulation, input and output rate changes, agonistic or antagonistic active metabolites, uptake into active site, slow receptor kinetics, delayed or modified activity, time-dependent protein binding and the use of racemic drugs among other factors. In this review, each of these various causes of hysteresis loops are discussed, with incorporation of relevant examples of drugs demonstrating these relationships for illustrative purposes. Furthermore, the effect that pharmaceutical formulation has on the occurrence and potential change in direction of the hysteresis loop, and the major pharmacokinetic / pharmacodynamic modeling approaches utilized to collapse and model hysteresis are detailed. PMID:24735761

Space-Time Fusion Under Error in Computer Model Output: An Application to Modeling Air Quality

EPA Science Inventory

In the last two decades a considerable amount of research effort has been devoted to modeling air quality with public health objectives. These objectives include regulatory activities such as setting standards along with assessing the relationship between exposure to air pollutan...

Does Rational Selection of Training and Test Sets Improve the Outcome of QSAR Modeling?

EPA Science Inventory

Prior to using a quantitative structure activity relationship (QSAR) model for external predictions, its predictive power should be established and validated. In the absence of a true external dataset, the best way to validate the predictive ability of a model is to perform its s...

MOAtox: A comprehensive mode of action and acute aquatic toxicity database for predictive model development (SETAC abstract)

EPA Science Inventory

The mode of toxic action (MOA) has been recognized as a key determinant of chemical toxicity and as an alternative to chemical class-based predictive toxicity modeling. However, the development of quantitative structure activity relationship (QSAR) and other models has been limit...

MOAtox: A Comprehensive Mode of Action and Acute Aquatic Toxicity Database for Predictive Model Development

EPA Science Inventory

tThe mode of toxic action (MOA) has been recognized as a key determinant of chemical toxicity andas an alternative to chemical class-based predictive toxicity modeling. However, the development ofquantitative structure activity relationship (QSAR) and other models has been limite...

Intermittent pair-housing, pair relationship qualities, and HPA activity in adult female rhesus macaques.

PubMed

Hannibal, Darcy L; Cassidy, Lauren C; Vandeleest, Jessica; Semple, Stuart; Barnard, Allison; Chun, Katie; Winkler, Sasha; McCowan, Brenda

2018-05-02

Laboratory rhesus macaques are often housed in pairs and may be temporarily or permanently separated for research, health, or management reasons. While both long-term social separations and introductions can stimulate a stress response that impacts inflammation and immune function, the effects of short-term overnight separations and whether qualities of the pair relationship mediate these effects are unknown. In this study, we investigated the effects of overnight separations on the urinary cortisol concentration of 20 differentially paired adult female rhesus macaques (Macaca mulatta) at the California National Primate Research Center. These females were initially kept in either continuous (no overnight separation) or intermittent (with overnight separation) pair-housing and then switched to the alternate pair-housing condition part way through the study. Each study subject was observed for 5 weeks, during which we collected measures of affiliative, aggressive, anxious, abnormal, and activity-state behaviors in both pair-housing conditions. Additionally, up to three urine samples were collected from each subject per week and assayed for urinary free cortisol and creatinine. Lastly, the behavioral observer scored each pair on four relationship quality attributes ("Anxious," "Tense," "Well-meshed," and "Friendly") using a seven-point scale. Data were analyzed using a generalized linear model with gamma distribution and an information theoretic approach to determine the best model set. An interaction between the intermittent pairing condition and tense pair adjective rating was in the top three models of the best model set. Dominance and rates of affiliation were also important for explaining urinary cortisol variation. Our results suggest that to prevent significant changes in HPA-axis activation in rhesus macaque females, which could have unintended effects on research outcomes, pairs with "Tense" relationships and overnight separations preventing tactile contact should be avoided. © 2018 Wiley Periodicals, Inc.

Exploring the relationships between International Classification of Functioning, Disability and Health (ICF) constructs of Impairment, Activity Limitation and Participation Restriction in people with osteoarthritis prior to joint replacement.

PubMed

Pollard, Beth; Johnston, Marie; Dieppe, Paul

2011-05-16

The International Classification of Functioning, Disability and Health (ICF) proposes three main constructs, impairment (I), activity limitation (A) and participation restriction (P). The ICF model allows for all paths between the constructs to be explored, with significant paths likely to vary for different conditions. The relationships between I, A and P have been explored in some conditions but not previously in people with osteoarthritis prior to joint replacement. The aim of this paper is to examine these relationships using separate measures of each construct and structural equation modelling. A geographical cohort of 413 patients with osteoarthritis about to undergo hip and knee joint replacement completed the Aberdeen measures of Impairment, Activity Limitation and Participation Restriction (Ab-IAP). Confirmatory factor analysis was used to test the three factor (I, A, P) measurement model. Structural equation modelling was used to explore the I, A and P pathways in the ICF model. There was support from confirmatory factor analysis for the three factor I, A, P measurement model. The structural equation model had good fit [S-B Chi-square = 439.45, df = 149, CFI robust = 0.91, RMSEA robust = 0.07] and indicated significant pathways between I and A (standardised coefficient = 0.76 p < 0.0001) and between A and P (standardised coefficient = 0.75 p < 0.0001). However, the path between I and P was not significant (standardised coefficient = 0.01). The significant pathways suggest that treatments and interventions aimed at reducing impairment, such as joint replacement, may only affect P indirectly, through A, however, longitudinal data would be needed to establish this.

Structure- and ligand-based structure-activity relationships for a series of inhibitors of aldolase.

PubMed

Ferreira, Leonardo G; Andricopulo, Adriano D

2012-12-01

Aldolase has emerged as a promising molecular target for the treatment of human African trypanosomiasis. Over the last years, due to the increasing number of patients infected with Trypanosoma brucei, there is an urgent need for new drugs to treat this neglected disease. In the present study, two-dimensional fragment-based quantitative-structure activity relationship (QSAR) models were generated for a series of inhibitors of aldolase. Through the application of leave-one-out and leave-many-out cross-validation procedures, significant correlation coefficients were obtained (r²=0.98 and q²=0.77) as an indication of the statistical internal and external consistency of the models. The best model was employed to predict pKi values for a series of test set compounds, and the predicted values were in good agreement with the experimental results, showing the power of the model for untested compounds. Moreover, structure-based molecular modeling studies were performed to investigate the binding mode of the inhibitors in the active site of the parasitic target enzyme. The structural and QSAR results provided useful molecular information for the design of new aldolase inhibitors within this structural class.

Antimicrobial Peptides Containing Unnatural Amino Acid Exhibit Potent Bactericidal Activity against ESKAPE Pathogens

DTIC Science & Technology

2013-01-01

compositions of these twobacteria’s cellmembranes are very differ- ent. The results of two 3D- QSARs (quantitative structure–activity relationship) studies...determined that there are five major physico- chemical descriptors necessary to define the activity of these AMPs in the S. aureus QSAR model.62 Five

Effects of change in physical activity on physical function limitations in older women: mediating roles of physical function performance and self-efficacy.

PubMed

McAuley, Edward; Morris, Katherine S; Doerksen, Shawna E; Motl, Robert W; Liang, Hu; White, Siobhan M; Wójcicki, Thomas R; Rosengren, Karl

2007-12-01

To examine the hypothesis that changes in self-efficacy and functional performance mediate, in part, the beneficial effect of physical activity on functional limitations over time. Prospective, observational study. Community-based. Two hundred forty-nine community-dwelling older women. Participants completed measures of self-reported physical activity, functional limitations, and self-efficacy. Four measures of physical function performance were also assessed. Measures were completed at baseline and 24 months. Data were analyzed using a panel model within a covariance modeling framework. Results indicated that increases in physical activity over time were associated with greater improvements in self-efficacy, which was associated in turn with improved physical function performance, both of which mediated the association between physical activity and functional limitations. Fewer functional limitations at baseline were also associated with higher levels of self-efficacy at 24 months. Age, race, and health status covariates did not significantly change these relationships. The findings support the mediating roles of self-efficacy and physical function performance in the relationship between longitudinal changes in physical activity and functional limitations in older women.

Integrated Modeling for Watershed Ecosystem Services Assessment and Forecasting

EPA Science Inventory

Regional scale watershed management decisions must be informed by the science-based relationship between anthropogenic activities on the landscape and the change in ecosystem structure, function, and services that occur as a result. We applied process-based models that represent...

QSAR Modeling: Where Have You Been? Where Are You Going To?.

EPA Science Inventory

Quantitative structure–activity relationship modeling is one of the major computational tools employed in medicinal chemistry. However, throughout its entire history it has drawn both praise and criticism concerning its reliability, limitations, successes, and failures. In this...

Total Charge Movement per Channel

PubMed Central

Sigg, Daniel; Bezanilla, Francisco

1997-01-01

One measure of the voltage dependence of ion channel conductance is the amount of gating charge that moves during activation and vice versa. The limiting slope method, introduced by Almers (Almers, W. 1978. Rev. Physiol. Biochem. Pharmacol. 82:96–190), exploits the relationship of charge movement and voltage sensitivity, yielding a lower limit to the range of single channel gating charge displacement. In practice, the technique is plagued by low experimental resolution due to the requirement that the logarithmic voltage sensitivity of activation be measured at very low probabilities of opening. In addition, the linear sequential models to which the original theory was restricted needed to be expanded to accommodate the complexity of mechanisms available for the activation of channels. In this communication, we refine the theory by developing a relationship between the mean activation charge displacement (a measure of the voltage sensitivity of activation) and the gating charge displacement (the integral of gating current). We demonstrate that recording the equilibrium gating charge displacement as an adjunct to the limiting slope technique greatly improves accuracy under conditions where the plots of mean activation charge displacement and gross gating charge displacement versus voltage can be superimposed. We explore this relationship for a wide variety of channel models, which include those having a continuous density of states, nonsequential activation pathways, and subconductance states. We introduce new criteria for the appropriate use of the limiting slope procedure and provide a practical example of the theory applied to low resolution simulation data. PMID:8997663

Appraisals to affect: Testing the integrative cognitive model of bipolar disorder.

PubMed

Palmier-Claus, Jasper E; Dodd, Alyson; Tai, Sara; Emsley, Richard; Mansell, Warren

2016-09-01

Cognitive models have suggested that extreme appraisals of affective states and maladaptive affect regulation strategies are important in the development of bipolar symptomatology. Little is known about the pathway by which these appraisals and behaviours interact in the formation of activated and depressed affective states. This study tested the predictions that (1) ascent behaviours mediate the relationship between positive appraisals of activated mood and activation; and (2) descent behaviours mediate the relationship between negative appraisals of activated mood and depression. A total of 52 individuals with a DSM-IV diagnosis of bipolar I or II disorder (confirmed by structured interview) completed biweekly assessments of affect regulation behaviours and mood for 4 weeks. Positive and negative appraisals of affective states were assessed at baseline through the Hypomanic Attitudes and Positive Prediction Inventory. Multilevel mediation analysis was used to explore the data. Ascent behaviours partially mediated the relationship between positive appraisals of activated mood and activation. Descent behaviours, but not negative appraisals of activated mood, predicted levels of depression indicating the absence of a mediation effect. The results suggest that positive appraisals of activated mood can escalate activation in individuals with bipolar disorder. Such appraisals may be inherently rewarding and reinforcing directly elevating levels of activation, whilst increasing individuals' use of ascent behaviours. The results are consistent with the view that appraisals and behaviours should be targeted during cognitive behavioural therapy for bipolar disorder. It may be beneficial to target positive appraisals of activated mood in cognitive behavioural therapy for mania. Cognitive behavioural therapists may also wish to focus on identifying and targeting individuals' use of ascent behaviours to reduce highly activated states. © 2015 The British Psychological Society.

THE FUTURE OF TOXICOLOGY-PREDICTIVE TOXICOLOGY: AN EXPANDED VIEW OF CHEMICAL TOXICITY

EPA Science Inventory

A chemistry approach to predictive toxicology relies on structure−activity relationship (SAR) modeling to predict biological activity from chemical structure. Such approaches have proven capabilities when applied to well-defined toxicity end points or regions of chemical space. T...

Application of quantitative structure activity relationship (QSAR) models to predict ozone toxicity in the lung.

PubMed

Kafoury, Ramzi M; Huang, Ming-Ju

2005-08-01

The sequence of events leading to ozone-induced airway inflammation is not well known. To elucidate the molecular and cellular events underlying ozone toxicity in the lung, we hypothesized that lipid ozonation products (LOPs) generated by the reaction of ozone with unsaturated fatty acids in the epithelial lining fluid and cell membranes play a key role in mediating ozone-induced airway inflammation. To test our hypothesis, we ozonized 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) and generated LOPs. Confluent human bronchial epithelial cells were exposed to the derivatives of ozonized POPC-9-oxononanoyl, 9-hydroxy-9-hydroperoxynonanoyl, and 8-(5-octyl-1,2,4-trioxolan-3-yl-)octanoyl-at a concentration of 10 muM, and the activity of phospholipases A2 (PLA2), C (PLC), and D (PLD) was measured (1, 0.5, and 1 h, respectively). Quantitative structure-activity relationship (QSAR) models were utilized to predict the biological activity of LOPs in airway epithelial cells. The QSAR results showed a strong correlation between experimental and computed activity (r = 0.97, 0.98, 0.99, for PLA2, PLC, and PLD, respectively). The results indicate that QSAR models can be utilized to predict the biological activity of the various ozone-derived LOP species in the lung. Copyright 2005 Wiley Periodicals, Inc.

Physical activity and quality of life in breast cancer survivors: the role of self-efficacy and health status.

PubMed

Phillips, Siobhan M; McAuley, Edward

2014-01-01

Mechanisms underlying the relationship between physical activity and quality of life (QOL) in breast cancer survivors are not well understood. The purpose of the present study was to longitudinally test a model examining self-efficacy and health status as potential mediators of this relationship. At baseline and 6 months, breast cancer survivors (n = 1527) completed physical activity, self-efficacy, health status, and QOL measures, and a subsample (n = 370) wore an accelerometer. Panel analysis within a covariance modeling framework was used to test the hypothesis that physical activity indirectly influences QOL across time. The hypothesized model provided a good fit in the full sample (χ(2)  = 409.06; d.f. = 91, p < 0.001; comparative fit index (CFI) = 0.98; standardized root mean residual (SRMR) = 0.04) and the accelerometer subsample (χ(2)  = 320.96, d.f. = 134, p < 0.001; CFI = 0.95; SRMR = 0.05), indicating that physical activity indirectly, via self-efficacy and health status indicators, influences QOL across time. Physical activity may influence QOL in breast cancer survivors through more proximal, modifiable factors. Copyright © 2013 John Wiley & Sons, Ltd.

A Novel Two-Step Hierarchical Quantitative Structure–Activity Relationship Modeling Work Flow for Predicting Acute Toxicity of Chemicals in Rodents

PubMed Central

Zhu, Hao; Ye, Lin; Richard, Ann; Golbraikh, Alexander; Wright, Fred A.; Rusyn, Ivan; Tropsha, Alexander

2009-01-01

Background Accurate prediction of in vivo toxicity from in vitro testing is a challenging problem. Large public–private consortia have been formed with the goal of improving chemical safety assessment by the means of high-throughput screening. Objective A wealth of available biological data requires new computational approaches to link chemical structure, in vitro data, and potential adverse health effects. Methods and results A database containing experimental cytotoxicity values for in vitro half-maximal inhibitory concentration (IC50) and in vivo rodent median lethal dose (LD50) for more than 300 chemicals was compiled by Zentralstelle zur Erfassung und Bewertung von Ersatz- und Ergaenzungsmethoden zum Tierversuch (ZEBET; National Center for Documentation and Evaluation of Alternative Methods to Animal Experiments). The application of conventional quantitative structure–activity relationship (QSAR) modeling approaches to predict mouse or rat acute LD50 values from chemical descriptors of ZEBET compounds yielded no statistically significant models. The analysis of these data showed no significant correlation between IC50 and LD50. However, a linear IC50 versus LD50 correlation could be established for a fraction of compounds. To capitalize on this observation, we developed a novel two-step modeling approach as follows. First, all chemicals are partitioned into two groups based on the relationship between IC50 and LD50 values: One group comprises compounds with linear IC50 versus LD50 relationships, and another group comprises the remaining compounds. Second, we built conventional binary classification QSAR models to predict the group affiliation based on chemical descriptors only. Third, we developed k-nearest neighbor continuous QSAR models for each subclass to predict LD50 values from chemical descriptors. All models were extensively validated using special protocols. Conclusions The novelty of this modeling approach is that it uses the relationships between in vivo and in vitro data only to inform the initial construction of the hierarchical two-step QSAR models. Models resulting from this approach employ chemical descriptors only for external prediction of acute rodent toxicity. PMID:19672406

A novel two-step hierarchical quantitative structure-activity relationship modeling work flow for predicting acute toxicity of chemicals in rodents.

PubMed

Zhu, Hao; Ye, Lin; Richard, Ann; Golbraikh, Alexander; Wright, Fred A; Rusyn, Ivan; Tropsha, Alexander

2009-08-01

Accurate prediction of in vivo toxicity from in vitro testing is a challenging problem. Large public-private consortia have been formed with the goal of improving chemical safety assessment by the means of high-throughput screening. A wealth of available biological data requires new computational approaches to link chemical structure, in vitro data, and potential adverse health effects. A database containing experimental cytotoxicity values for in vitro half-maximal inhibitory concentration (IC(50)) and in vivo rodent median lethal dose (LD(50)) for more than 300 chemicals was compiled by Zentralstelle zur Erfassung und Bewertung von Ersatz- und Ergaenzungsmethoden zum Tierversuch (ZEBET; National Center for Documentation and Evaluation of Alternative Methods to Animal Experiments). The application of conventional quantitative structure-activity relationship (QSAR) modeling approaches to predict mouse or rat acute LD(50) values from chemical descriptors of ZEBET compounds yielded no statistically significant models. The analysis of these data showed no significant correlation between IC(50) and LD(50). However, a linear IC(50) versus LD(50) correlation could be established for a fraction of compounds. To capitalize on this observation, we developed a novel two-step modeling approach as follows. First, all chemicals are partitioned into two groups based on the relationship between IC(50) and LD(50) values: One group comprises compounds with linear IC(50) versus LD(50) relationships, and another group comprises the remaining compounds. Second, we built conventional binary classification QSAR models to predict the group affiliation based on chemical descriptors only. Third, we developed k-nearest neighbor continuous QSAR models for each subclass to predict LD(50) values from chemical descriptors. All models were extensively validated using special protocols. The novelty of this modeling approach is that it uses the relationships between in vivo and in vitro data only to inform the initial construction of the hierarchical two-step QSAR models. Models resulting from this approach employ chemical descriptors only for external prediction of acute rodent toxicity.

Sleep Disturbance and Depression Symptoms Mediate the Relationship between Pain and Cognitive Dysfunction in Lupus Patients.

PubMed

Lillis, Teresa A; Tirone, Vanessa; Gandhi, Nisarg; Weinberg, Stacy; Nika, Ailda; Sequeira, Winston; Hobfoll, Stevan E; Block, Joel A; Jolly, Meenakshi

2018-05-04

The current study explored whether sleep disturbance and depression symptoms mediated the relationship between pain and Cognitive Dysfunction (CD) in a sample of 115 patients with Systemic Lupus Erythematosus (SLE). 115 consenting SLE patients completed questionnaires on pain, perceived stress, depression, sleep, and CD. Relationships among pain, sleep, depression and CD were assessed with bootstrapped mediation models controlling for race/ethnicity, fibromyalgia diagnosis, current corticosteroid use, disease activity and damage, and perceived stress. Mediation analyses indicated that the effect of pain on CD was mediated by sleep disturbance (β = 0.30) and depression symptoms (β = 0.33). These effects were maintained even after controlling for aforementioned covariates, of which, only disease activity (β= 0.20) and stress (β=.22) remained significantly linked to CD [Overall Model R 2 = .53; all p's <.05). Even after controlling for disease activity and perceived stress, the relationship between pain and CD was explained by sleep disturbance and depression symptoms. Although these relationships need validation in longitudinal studies with additional measurement modalities, our findings may indicate promising, non-pharmacologic intervention avenues for SLE patients with pain and CD. Specifically, cognitive-behavioral therapies for depression and sleep are known to reduce distress and enhance functioning across various psychosocial domains. Given the symptom burden of SLE, interventions that maximize potential benefits without additional pharmacologic treatments may be of particular utility. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

A novel simple QSAR model for the prediction of anti-HIV activity using multiple linear regression analysis.

PubMed

Afantitis, Antreas; Melagraki, Georgia; Sarimveis, Haralambos; Koutentis, Panayiotis A; Markopoulos, John; Igglessi-Markopoulou, Olga

2006-08-01

A quantitative-structure activity relationship was obtained by applying Multiple Linear Regression Analysis to a series of 80 1-[2-hydroxyethoxy-methyl]-6-(phenylthio) thymine (HEPT) derivatives with significant anti-HIV activity. For the selection of the best among 37 different descriptors, the Elimination Selection Stepwise Regression Method (ES-SWR) was utilized. The resulting QSAR model (R (2) (CV) = 0.8160; S (PRESS) = 0.5680) proved to be very accurate both in training and predictive stages.

Predictors of body appearance cognitive distraction during sexual activity in a sample of men with ED.

PubMed

Pascoal, P M; Raposo, C F; Oliveira, L B

2015-01-01

Our aim is to scrutinize the extent to which aspects of body dissatisfaction and relationship variables predict body appearance cognitive distraction during sexual activity (BACDSA) in a sample of men diagnosed with ED. A total of 65 heterosexual Portuguese participants with ED completed a survey that included questions on socio-demographic data as well as body-related and relationship measures. We used the Global Body Dissatisfaction (GBD) Subscale of the Body Attitudes Test; a version of the Contour Drawing Rating Scale; a single item on partner's opinion perceived about one's body appearance; the Global Measure of Relationship Satisfaction; and the Inclusion of Other in Self Scale. Open questions assessed focus on specific body parts during sexual activity and relationship length. Hierarchical multiple regression indicated that only GBD was a significant predictor of BACDSA, contrary to the relationship measures that showed no significant predictive effect (R(2) =0.47). Our results support the important role of individual factors on explanatory models of sexual dysfunctions, suggesting that interventions addressing individual factors that affect BACDSA may be of preference.

Synthesis, Antifungal Activity and Structure-Activity Relationships of Novel 3-(Difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic Acid Amides.

PubMed

Du, Shijie; Tian, Zaimin; Yang, Dongyan; Li, Xiuyun; Li, Hong; Jia, Changqing; Che, Chuanliang; Wang, Mian; Qin, Zhaohai

2015-05-08

A series of novel 3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid amides were synthesized and their activities were tested against seven phytopathogenic fungi by an in vitro mycelia growth inhibition assay. Most of them displayed moderate to excellent activities. Among them N-(2-(5-bromo-1H-indazol-1-yl)phenyl)-3-(difluoro-methyl)-1-methyl-1H-pyrazole-4-carboxamide (9m) exhibited higher antifungal activity against the seven phytopathogenic fungi than boscalid. Topomer CoMFA was employed to develop a three-dimensional quantitative structure-activity relationship model for the compounds. In molecular docking, the carbonyl oxygen atom of 9m could form hydrogen bonds towards the hydroxyl of TYR58 and TRP173 on SDH.

Quantitative Structure-Antifungal Activity Relationships for cinnamate derivatives.

PubMed

Saavedra, Laura M; Ruiz, Diego; Romanelli, Gustavo P; Duchowicz, Pablo R

2015-12-01

Quantitative Structure-Activity Relationships (QSAR) are established with the aim of analyzing the fungicidal activities of a set of 27 active cinnamate derivatives. The exploration of more than a thousand of constitutional, topological, geometrical and electronic molecular descriptors, which are calculated with Dragon software, leads to predictions of the growth inhibition on Pythium sp and Corticium rolfsii fungi species, in close agreement to the experimental values extracted from the literature. A set containing 21 new structurally related cinnamate compounds is prepared. The developed QSAR models are applied to predict the unknown fungicidal activity of this set, showing that cinnamates like 38, 28 and 42 are expected to be highly active for Pythium sp, while this is also predicted for 28 and 34 in C. rolfsii. Copyright © 2015 Elsevier Inc. All rights reserved.

Structure-Activity Relationships for the Antifungal Activity of Selective Estrogen Receptor Antagonists Related to Tamoxifen

PubMed Central

Butts, Arielle; Martin, Jennifer A.; DiDone, Louis; Bradley, Erin K.; Mutz, Mitchell; Krysan, Damian J.

2015-01-01

Cryptococcosis is one of the most important invasive fungal infections and is a significant contributor to the mortality associated with HIV/AIDS. As part of our program to repurpose molecules related to the selective estrogen receptor modulator (SERM) tamoxifen as anti-cryptococcal agents, we have explored the structure-activity relationships of a set of structurally diverse SERMs and tamoxifen derivatives. Our data provide the first insights into the structural requirements for the antifungal activity of this scaffold. Three key molecular characteristics affecting anti-cryptococcal activity emerged from our studies: 1) the presence of an alkylamino group tethered to one of the aromatic rings of the triphenylethylene core; 2) an appropriately sized aliphatic substituent at the 2 position of the ethylene moiety; and 3) electronegative substituents on the aromatic rings modestly improved activity. Using a cell-based assay of calmodulin antagonism, we found that the anti-cryptococcal activity of the scaffold correlates with calmodulin inhibition. Finally, we developed a homology model of C. neoformans calmodulin and used it to rationalize the structural basis for the activity of these molecules. Taken together, these data and models provide a basis for the further optimization of this promising anti-cryptococcal scaffold. PMID:26016941

Antitumor activity of 3,4-ethylenedioxythiophene derivatives and quantitative structure-activity relationship analysis

NASA Astrophysics Data System (ADS)

Jukić, Marijana; Rastija, Vesna; Opačak-Bernardi, Teuta; Stolić, Ivana; Krstulović, Luka; Bajić, Miroslav; Glavaš-Obrovac, Ljubica

2017-04-01

The aim of this study was to evaluate nine newly synthesized amidine derivatives of 3,4- ethylenedioxythiophene (3,4-EDOT) for their cytotoxic activity against a panel of human cancer cell lines and to perform a quantitative structure-activity relationship (QSAR) analysis for the antitumor activity of a total of 27 3,4-ethylenedioxythiophene derivatives. Induction of apoptosis was investigated on the selected compounds, along with delivery options for the optimization of activity. The best obtained QSAR models include the following group of descriptors: BCUT, WHIM, 2D autocorrelations, 3D-MoRSE, GETAWAY descriptors, 2D frequency fingerprint and information indices. Obtained QSAR models should be relieved in elucidation of important physicochemical and structural requirements for this biological activity. Highly potent molecules have a symmetrical arrangement of substituents along the x axis, high frequency of distance between N and O atoms at topological distance 9, as well as between C and N atoms at topological distance 10, and more C atoms located at topological distances 6 and 3. Based on the conclusion given in the QSAR analysis, a new compound with possible great activity was proposed.

Time with friends and physical activity as mechanisms linking obesity and television viewing among youth.

PubMed

Vandewater, Elizabeth A; Park, Seoung Eun; Hébert, Emily T; Cummings, Hope M

2015-07-27

Though bivariate relationships between childhood obesity, physical activity, friendships and television viewing are well documented, empirical assessment of the extent to which links between obesity and television may be mediated by these factors is scarce. This study examines the possibility that time with friends and physical activity are potential mechanisms linking overweight/obesity to television viewing in youth. Data were drawn from children ages 10-18 years old (M = 13.81, SD = 2.55) participating in the 2002 wave of Child Development Supplement (CDS) to the Panel Study of Income Dynamics (PSID) (n = 1,545). Data were collected both directly and via self-report from children and their parents. Path analysis was employed to examine a model whereby the relationships between youth overweight/obesity and television viewing were mediated by time spent with friends and moderate-to-vigorous physical activity (MVPA). Overweight/obesity was directly related to less time spent with friends, but not to MVPA. Time spent with friends was directly and positively related to MVPA, and directly and negatively related to time spent watching television without friends. In turn, MVPA was directly and negatively related to watching television without friends. There were significant indirect effects of both overweight/obesity and time with friends on television viewing through MVPA, and of overweight/obesity on MVPA through time with friends. Net of any indirect effects, the direct effect of overweight/obesity on television viewing remained. The final model fit the data extremely well (χ2 = 5.77, df = 5, p<0.0001, RMSEA = 0.01, CFI = 0.99, TLI =0.99). We found good evidence that the positive relationships between time with friends and physical activity are important mediators of links between overweight/obesity and television viewing in youth. These findings highlight the importance of moving from examinations of bivariate relationships between weight status and television viewing to more nuanced explanatory models which attempt to identify and unpack the possible mechanisms linking them.

Physical Activity Among Female Adolescents in Jeddah, Saudi Arabia: A Health Promotion Model-Based Path Analysis.

PubMed

Bajamal, Eman; Robbins, Lorraine B; Ling, Jiying; Smith, Barbara; Pfeiffer, Karin A; Sharma, Dhruv

In Saudi Arabia, about 14.8% of female children and adolescents of less than 20 years old are obese, compared with only 9.4% of male children and adolescents. One major factor linked to the high prevalence of obesity and related chronic illnesses involves inadequate physical activity (PA). Only 25% of female adolescents in Saudi Arabia meet the recommendation calling for 60 minutes of moderate to vigorous PA per day. The aim of this research was to examine relationships among self-reported PA and cognitive and affective variables, including perceived barriers to PA, PA self-efficacy, enjoyment of PA, social support for PA, and commitment to PA. Female Saudi adolescents 13-18 years of age were recruited from 10 public intermediate and high schools in Jeddah, Saudi Arabia. Female adolescents who met the inclusion criteria completed surveys and participated in height and weight measurements at schools. A structural equation model based on the health promotion model was estimated, with commitment to PA hypothesized to mediate relationships between health promotion model (HPM) predictors and self-reported PA. A total of 405 female adolescents with a mean age of 15.4 years took part in the study, of whom 25.3% were overweight or obese. Mean PA level measured via the Physical Activity Questionnaire for Adolescents was 2.1 (SD = 0.66), which is low. Commitment to PA partially mediated the relationships of PA self-efficacy, enjoyment of PA, and social support for PA; 25.4% of the variance in PA was explained. The model did not support the indirect relationship of perceived barriers through commitment or the direct relationship between enjoyment and PA. This study indicates that Saudi female adolescents are in need of interventions to increase their PA. The findings suggest that addressing perceived barriers to PA and targeting PA self-efficacy, enjoyment of PA, and social support for PA to enhance commitment to PA may be a fruitful approach in nursing interventions to increase PA among Saudi female adolescents.

Predicting physical activity and fruit and vegetable intake in adolescents: a test of the information, motivation, behavioral skills model.

PubMed

Kelly, Stephanie; Melnyk, Bernadette Mazurek; Belyea, Michael

2012-04-01

Most adolescents do not meet national recommendations regarding physical activity and/or the intake of fruits and vegetables. The purpose of this study was to explore whether variables in the information, motivation, behavioral skills (IMB) model of health promotion predicted physical activity and fruit and vegetable intake in 404 adolescents from 2 high schools in the Southwest United States using structural equation modeling (SEM). The SEM models included theoretical constructs, contextual variables, and moderators. The theoretical relationships in the IMB model were confirmed and were moderated by gender and race. Interventions that incorporate cognitive-behavioral skills building may be a key factor for promoting physical activity as well as fruit and vegetable intake in adolescents. Copyright © 2012 Wiley Periodicals, Inc.

The Distributed Lambda (?) Model (DLM): A 3-D, Finite-Element Muscle Model Based on Feldman's ? Model; Assessment of Orofacial Gestures

ERIC Educational Resources Information Center

Nazari, Mohammad Ali; Perrier, Pascal; Payan, Yohan

2013-01-01

Purpose: The authors aimed to design a distributed lambda model (DLM), which is well adapted to implement three-dimensional (3-D), finite-element descriptions of muscles. Method: A muscle element model was designed. Its stress-strain relationships included the active force-length characteristics of the ? model along the muscle fibers, together…

Quantitative structure activity relationship studies of mushroom tyrosinase inhibitors

NASA Astrophysics Data System (ADS)

Xue, Chao-Bin; Luo, Wan-Chun; Ding, Qi; Liu, Shou-Zhu; Gao, Xing-Xiang

2008-05-01

Here, we report our results from quantitative structure-activity relationship studies on tyrosinase inhibitors. Interactions between benzoic acid derivatives and tyrosinase active sites were also studied using a molecular docking method. These studies indicated that one possible mechanism for the interaction between benzoic acid derivatives and the tyrosinase active site is the formation of a hydrogen-bond between the hydroxyl (aOH) and carbonyl oxygen atoms of Tyr98, which stabilized the position of Tyr98 and prevented Tyr98 from participating in the interaction between tyrosinase and ORF378. Tyrosinase, also known as phenoloxidase, is a key enzyme in animals, plants and insects that is responsible for catalyzing the hydroxylation of tyrosine into o-diphenols and the oxidation of o-diphenols into o-quinones. In the present study, the bioactivities of 48 derivatives of benzaldehyde, benzoic acid, and cinnamic acid compounds were used to construct three-dimensional quantitative structure-activity relationship (3D-QSAR) models using comparative molecular field (CoMFA) and comparative molecular similarity indices (CoMSIA) analyses. After superimposition using common substructure-based alignments, robust and predictive 3D-QSAR models were obtained from CoMFA ( q 2 = 0.855, r 2 = 0.978) and CoMSIA ( q 2 = 0.841, r 2 = 0.946), with 6 optimum components. Chemical descriptors, including electronic (Hammett σ), hydrophobic (π), and steric (MR) parameters, hydrogen bond acceptor (H-acc), and indicator variable ( I), were used to construct a 2D-QSAR model. The results of this QSAR indicated that π, MR, and H-acc account for 34.9, 31.6, and 26.7% of the calculated biological variance, respectively. The molecular interactions between ligand and target were studied using a flexible docking method (FlexX). The best scored candidates were docked flexibly, and the interaction between the benzoic acid derivatives and the tyrosinase active site was elucidated in detail. We believe that the QSAR models built here provide important information necessary for the design of novel tyrosinase inhibitors.

Effects of current physical activity on affective response to exercise: Physical and social-cognitive mechanisms

PubMed Central

Magnan, Renee E.; Kwan, Bethany M.; Bryan, Angela D.

2012-01-01

Objective Affective responses during exercise are often important determinants of exercise initiation and maintenance. Current physical activity may be one individual difference that is associated with the degree to which individuals have positive (or negative) affective experiences during exercise. The objective of this investigation was to explore physical and cognitive explanations of the relationship between current activity status (more versus less active) and affective response during a 30-minute bout of moderate-intensity exercise. Method Participants reported their current level of physical activity, exercise self-efficacy, and affect during a 30-minute bout of moderate-intensity exercise. Results More active individuals experienced higher levels of positive affect and tranquility and lower levels of negative affect and fatigue during exercise. Multivariate models for each affective state indicated separate processes through which physical activity may be associated with changes in affect during exercise. Conclusions These models indicate that affect experienced during physical activity is related to current activity level and these relationships can be partially explained by the physical and cognitive factors explored in this study. Recommendations for future research to elucidate whether positive affective response to physical activity improves as a function of becoming more active over time are discussed. PMID:23088712

SAR STUDY OF NASAL TOXICITY: LESSONS FOR MODELING SMALL TOXICITY DATASETS

EPA Science Inventory

Most toxicity data, particularly from whole animal bioassays, are generated without the needs or capabilities of structure-activity relationship (SAR) modeling in mind. Some toxicity endpoints have been of sufficient regulatory concern to warrant large scale testing efforts (e.g....

CALCULATING PHYSICAL PROPERTIES OF ORGANIC COMPOUNDS FOR ENVIRONMENTAL MODELING FROM MOLECULAR STRUCTURE

EPA Science Inventory

Mathematical models for predicting the transport and fate of pollutants in the environment require reactivity parameter values-- that is value of the physical and chemical constants that govern reactivity. Although empirical structure activity relationships have been developed t...

Estimating the Potential Toxicity of Chemicals Associated with Hydraulic Fracturing Operations Using Quantitative Structure-Activity Relationship Modeling

EPA Pesticide Factsheets

Researchers facilitated evaluation of chemicals that lack chronic oral toxicity values using a QSAR model to develop estimates of potential toxicity for chemicals used in HF fluids or found in flowback or produced water

Quantitative structure-activity relationships of selective antagonists of glucagon receptor using QuaSAR descriptors.

PubMed

Manoj Kumar, Palanivelu; Karthikeyan, Chandrabose; Hari Narayana Moorthy, Narayana Subbiah; Trivedi, Piyush

2006-11-01

In the present paper, quantitative structure activity relationship (QSAR) approach was applied to understand the affinity and selectivity of a novel series of triaryl imidazole derivatives towards glucagon receptor. Statistically significant and highly predictive QSARs were derived for glucagon receptor inhibition by triaryl imidazoles using QuaSAR descriptors of molecular operating environment (MOE) employing computer-assisted multiple regression procedure. The generated QSAR models revealed that factors related to hydrophobicity, molecular shape and geometry predominantly influences glucagon receptor binding affinity of the triaryl imidazoles indicating the relevance of shape specific steric interactions between the molecule and the receptor. Further, QSAR models formulated for selective inhibition of glucagon receptor over p38 mitogen activated protein (MAP) kinase of the compounds in the series highlights that the same structural features, which influence the glucagon receptor affinity, also contribute to their selective inhibition.

Validation of the Soil Moisture Active Passive (SMAP) satellite soil moisture retrieval in an Arctic tundra environment

NASA Astrophysics Data System (ADS)

Wrona, Elizabeth; Rowlandson, Tracy L.; Nambiar, Manoj; Berg, Aaron A.; Colliander, Andreas; Marsh, Philip

2017-05-01

This study examines the Soil Moisture Active Passive soil moisture product on the Equal Area Scalable Earth-2 (EASE-2) 36 km Global cylindrical and North Polar azimuthal grids relative to two in situ soil moisture monitoring networks that were installed in 2015 and 2016. Results indicate that there is no relationship between the Soil Moisture Active Passive (SMAP) Level-2 passive soil moisture product and the upscaled in situ measurements. Additionally, there is very low correlation between modeled brightness temperature using the Community Microwave Emission Model and the Level-1 C SMAP brightness temperature interpolated to the EASE-2 Global grid; however, there is a much stronger relationship to the brightness temperature measurements interpolated to the North Polar grid, suggesting that the soil moisture product could be improved with interpolation on the North Polar grid.

Progress in the Visualization and Mining of Chemical and Target Spaces.

PubMed

Medina-Franco, José L; Aguayo-Ortiz, Rodrigo

2013-12-01

Chemogenomics is a growing field that aims to integrate the chemical and target spaces. As part of a multi-disciplinary effort to achieve this goal, computational methods initially developed to visualize the chemical space of compound collections and mine single-target structure-activity relationships, are being adapted to visualize and mine complex relationships in chemogenomics data sets. Similarly, the growing evidence that clinical effects are many times due to the interaction of single or multiple drugs with multiple targets, is encouraging the development of novel methodologies that are integrated in multi-target drug discovery endeavors. Herein we review advances in the development and application of approaches to generate visual representations of chemical space with particular emphasis on methods that aim to explore and uncover relationships between chemical and target spaces. Also, progress in the data mining of the structure-activity relationships of sets of compounds screened across multiple targets are discussed in light of the concept of activity landscape modeling. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigating the Relationship between Job Satisfaction Levels of the Teachers in Educational Institutions and Their Attitudes towards Teaching Profession

ERIC Educational Resources Information Center

Üredi, Lütfi

2017-01-01

The basic purpose of this research was to investigate the relationship between job satisfaction levels of the teachers in educational institutions and their attitudes towards teaching profession. Obtained results provided significant contributions for improving the quality of educational activities. Relational screening model as one of the…

Synthesis, structure-activity relationships, and in vivo evaluation of N3-phenylpyrazinones as novel corticotropin-releasing factor-1 (CRF1) receptor antagonists.

PubMed

Hartz, Richard A; Ahuja, Vijay T; Arvanitis, Argyrios G; Rafalski, Maria; Yue, Eddy W; Denhart, Derek J; Schmitz, William D; Ditta, Jonathan L; Deskus, Jeffrey A; Brenner, Allison B; Hobbs, Frank W; Payne, Joseph; Lelas, Snjezana; Li, Yu-Wen; Molski, Thaddeus F; Mattson, Gail K; Peng, Yong; Wong, Harvey; Grace, James E; Lentz, Kimberley A; Qian-Cutrone, Jingfang; Zhuo, Xiaoliang; Shu, Yue-Zhong; Lodge, Nicholas J; Zaczek, Robert; Combs, Andrew P; Olson, Richard E; Bronson, Joanne J; Mattson, Ronald J; Macor, John E

2009-07-23

Evidence suggests that corticotropin-releasing factor-1 (CRF(1)) receptor antagonists may offer therapeutic potential for the treatment of diseases associated with elevated levels of CRF such as anxiety and depression. A pyrazinone-based chemotype of CRF(1) receptor antagonists was discovered. Structure-activity relationship studies led to the identification of numerous potent analogues including 12p, a highly potent and selective CRF(1) receptor antagonist with an IC(50) value of 0.26 nM. The pharmacokinetic properties of 12p were assessed in rats and Cynomolgus monkeys. Compound 12p was efficacious in the defensive withdrawal test (an animal model of anxiety) in rats. The synthesis, structure-activity relationships and in vivo properties of compounds within the pyrazinone chemotype are described.

Alignment-independent technique for 3D QSAR analysis

NASA Astrophysics Data System (ADS)

Wilkes, Jon G.; Stoyanova-Slavova, Iva B.; Buzatu, Dan A.

2016-04-01

Molecular biochemistry is controlled by 3D phenomena but structure-activity models based on 3D descriptors are infrequently used for large data sets because of the computational overhead for determining molecular conformations. A diverse dataset of 146 androgen receptor binders was used to investigate how different methods for defining molecular conformations affect the performance of 3D-quantitative spectral data activity relationship models. Molecular conformations tested: (1) global minimum of molecules' potential energy surface; (2) alignment-to-templates using equal electronic and steric force field contributions; (3) alignment using contributions "Best-for-Each" template; (4) non-energy optimized, non-aligned (2D > 3D). Aggregate predictions from models were compared. Highest average coefficients of determination ranged from R Test 2 = 0.56 to 0.61. The best model using 2D > 3D (imported directly from ChemSpider) produced R Test 2 = 0.61. It was superior to energy-minimized and conformation-aligned models and was achieved in only 3-7 % of the time required using the other conformation strategies. Predictions averaged from models built on different conformations achieved a consensus R Test 2 = 0.65. The best 2D > 3D model was analyzed for underlying structure-activity relationships. For the compound strongest binding to the androgen receptor, 10 substructural features contributing to binding were flagged. Utility of 2D > 3D was compared for two other activity endpoints, each modeling a medium sized data set. Results suggested that large scale, accurate predictions using 2D > 3D SDAR descriptors may be produced for interactions involving endocrine system nuclear receptors and other data sets in which strongest activities are produced by fairly inflexible substrates.

Antecedents and mediators of physical activity in endometrial cancer survivors: Increasing physical activity through Steps to Health

PubMed Central

Cox, Matthew; Carmack, Cindy; Hughes, Daniel; Baum, George; Brown, Jubilee; Jhingran, Anuja; Lu, Karen; Basen-Engquist, Karen

2015-01-01

OBJECTIVE Research shows that physical activity (PA) has a positive effect on cancer survivors including improving quality of life, improving physical fitness, and decreasing risk for cancer recurrence in some cancer types. Theory-based intervention approaches have identified self-efficacy as a potential mediator of PA interventions. This study examines the temporal relationships at four time points (T1–T4) between several social cognitive theory constructs and PA among a group of endometrial cancer survivors receiving a PA intervention. METHOD A sample of 98 sedentary women who were at least six months post treatment for endometrial cancer were given an intervention to increase their PA. The study tested whether modeling, physiological somatic sensations, and social support at previous time points predicted self-efficacy at later time points, which in turn predicted PA at later time points. RESULTS Results indicate that as physiological somatic sensations at T2 decrease, self-efficacy at T3 increases, which leads to an increase in PA at T4. This suggests that self-efficacy is a significant mediator between physiological somatic sensations and PA. Exploratory follow up models suggest model fit can be improved with the addition of contemporaneous effects between self-efficacy and PA at T3 and T4, changing the timing of the mediational relationships. CONCLUSIONS Physiological somatic sensations appear to be an important construct to target in order to increase PA in this population. While self-efficacy appeared to mediate the relationship between physiological somatic sensations and PA, the timing of this relationship is requires further study. PMID:25642840

Toward the identification of a reliable 3D-QSAR model for the protein tyrosine phosphatase 1B inhibitors

NASA Astrophysics Data System (ADS)

Wang, Fangfang; Zhou, Bo

2018-04-01

Protein tyrosine phosphatase 1B (PTP1B) is an intracellular non-receptor phosphatase that is implicated in signal transduction of insulin and leptin pathways, thus PTP1B is considered as potential target for treating type II diabetes and obesity. The present article is an attempt to formulate the three-dimensional quantitative structure-activity relationship (3D-QSAR) modeling of a series of compounds possessing PTP1B inhibitory activities using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques. The optimum template ligand-based models are statistically significant with great CoMFA (R2cv = 0.600, R2pred = 0.6760) and CoMSIA (R2cv = 0.624, R2pred = 0.8068) values. Molecular docking was employed to elucidate the inhibitory mechanisms of this series of compounds against PTP1B. In addition, the CoMFA and CoMSIA field contour maps agree well with the structural characteristics of the binding pocket of PTP1B active site. The knowledge of structure-activity relationship and ligand-receptor interactions from 3D-QSAR model and molecular docking will be useful for better understanding the mechanism of ligand-receptor interaction and facilitating development of novel compounds as potent PTP1B inhibitors.

Application of the Transtheoretical Model of behavior change to the physical activity behavior of WIC mothers.

PubMed

Fahrenwald, Nancy L; Walker, Susan Noble

2003-01-01

This descriptive-correlational study examined the Transtheoretical Model (TTM) of behavior change in relationship to the physical activity behavior of mothers receiving assistance from the Women, Infants, and Children program. A purposive sample (N = 30) of six women at each of the five stages of readiness for behavior change was used. Relationships between stage of behavior change (measured using the Stage of Exercise Adoption tool) and other TTM constructs were examined. The constructs and corresponding instruments included physical activity behavior (Seven-Day Physical Activity Recall), pros, cons, decisional balance (Exercise Benefits/Barriers Scale and two open-ended questions), self-efficacy (Self-efficacy for Exercise scale), and processes of behavior change (Processes of Exercise Adoption tool and the Social Support for Exercise scale). Significant relationships were found between stage of behavior change and two physical activity energy expenditure indices (rs = 0.71-0.73, p < 0.01), daily minutes of moderate to very hard physical activity (rs = 0.81, p < 0.01), pros (rs = 0.56, p < 0.01), cons (rs = -0.52, p < 0.05), decisional balance (rs = 0.56, p < 0.01), and self-efficacy (rs = 0.56, p < 0.01). Use of the 10 processes of change differed by stage of change. Pros to physical activity included a sense of accomplishment, increased strength, stress relief, and getting in shape after pregnancy. Cons included fatigue, childcare, and cold weather. Results support the TTM as relevant to WIC mothers and suggest strategies to increase physical activity in this population.

A Comparative Study of Successful Central Nervous System Drugs Using Molecular Modeling

ERIC Educational Resources Information Center

Kim, Hyosub; Sulaimon, Segun; Menezes, Sandra; Son, Anne; Menezes, Warren J. C.

2011-01-01

Molecular modeling is a powerful tool used for three-dimensional visualization and for exploring electrostatic forces involved in drug transport. This tool enhances student understanding of structure-property relationships, as well as actively engaging them in class. Molecular modeling of several central nervous system (CNS) drugs is used to…

Heuristic-Leadership Model: Adapting to Current Training and Changing Times.

ERIC Educational Resources Information Center

Danielson, Mary Ann

A model was developed for training individuals to adapt better to the changing work environment by focusing on the subordinate to supervisor relationship and providing a heuristic approach to leadership. The model emphasizes a heuristic approach to decision-making through the active participation of both members of the dyad. The demand among…

INFLUENCE OF MATRIX FORMULATION ON DERMAL PERCUTANEOUS ABSORPTION OF TRIAZOLE FUNGICIDES USING QSAR AND PBPK / PD MODELS

EPA Science Inventory

The objective of this work is to use the Exposure Related Dose Estimating Model (ERDEM) and quantitative structure-activity relationship (QSAR) models to develop an assessment tool for human exposure assessment to triazole fungicides. A dermal exposure route is used for the physi...

Toxic Hazards Research Unit Annual Report: 1987

DTIC Science & Technology

1988-03-01

Low Density Lipoproteins and in Model Membranes 14 Sep Is Cigarette Smoking Neurotoric? Mr. Steven Goden Dr. R. Kutzman 4> ’October 1986 through September 1987 2I ...based pharmcokinetic model phosphoniteo,o-diethylmethyl quantitative structure activity relationship respiratory epithelium Salmonella sensitization j...in Cultured Respiratory Epithelial Cells ----------------------- ------------ 73 6 PHARMACOKINETIC AND PHARMACODYNAMIC MODELING .------------------ 78

Clustered multistate models with observation level random effects, mover-stayer effects and dynamic covariates: modelling transition intensities and sojourn times in a study of psoriatic arthritis.

PubMed

Yiu, Sean; Farewell, Vernon T; Tom, Brian D M

2018-02-01

In psoriatic arthritis, it is important to understand the joint activity (represented by swelling and pain) and damage processes because both are related to severe physical disability. The paper aims to provide a comprehensive investigation into both processes occurring over time, in particular their relationship, by specifying a joint multistate model at the individual hand joint level, which also accounts for many of their important features. As there are multiple hand joints, such an analysis will be based on the use of clustered multistate models. Here we consider an observation level random-effects structure with dynamic covariates and allow for the possibility that a subpopulation of patients is at minimal risk of damage. Such an analysis is found to provide further understanding of the activity-damage relationship beyond that provided by previous analyses. Consideration is also given to the modelling of mean sojourn times and jump probabilities. In particular, a novel model parameterization which allows easily interpretable covariate effects to act on these quantities is proposed.

Database Technology Activities and Assessment for Defense Modeling and Simulation Office (DMSO) (August 1991-November 1992). A Documented Briefing

DTIC Science & Technology

1994-01-01

databases and identifying new data entities, data elements, and relationships . - Standard data naming conventions, schema, and definition processes...management system. The use of such a tool could offer: (1) structured support for representation of objects and their relationships to each other (and...their relationships to related multimedia objects such as an engineering drawing of the tank object or a satellite image that contains the installation

Varic acid analogues from fungus as PTP1B inhibitors: Biological evaluation and structure-activity relationships.

PubMed

Sun, Wenlong; Zhuang, Chunlin; Li, Xia; Zhang, Bowei; Lu, Xinhua; Zheng, Zhihui; Dong, Yuesheng

2017-08-01

Protein tyrosine phosphatase 1B (PTP1B) inhibitors as potential therapies for diabetes and obesity have attracted much attention in recent years. Six varic acid analogues were isolated from two strains of fungi and evaluated for PTP1B inhibition activities. The structure-activity relationships were also characterized and predicted by molecular modeling. Further kinetic studies indicated the reversible and competitive inhibition manner of varic acid analogues. Trivaric acid showed insulin-sensitizing effect not only in vitro but also in vivo, representing a promising lead compound for further optimization. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Mediating Effect of Innovation between Total Quality Management (TQM) and Business Performance

NASA Astrophysics Data System (ADS)

Shan, Ang Wei; Fauzi Ahmad, Mohd; Hisyamudin Muhd Nor, Nik

2016-11-01

Both TQM and Innovation are the competitive key factors that intensely embedded into organizational products, service and process. In order to achieve higher business performance, organizations are needed to adopt both quality and innovation. Therefore, the main objective of this paper is to identify the relationship between TQM and business performance with a mediator's effect of Innovation. After detailed review the extensive literature, a new TQM model is presented. The proposed model integrates the TQM practices and different type of innovation attempt to develop a theoretical knowledge to help academician and manufacturer to understand the relationship that design quality in product and service and engaging innovation in the activities. To this end, the SEM-PLS (Structural Equation Modelling - Partial Least Squares Structural) is used to identify and evaluate the relationship among TQM, Innovation and business performance in establishing a new TQM model.

Relationships among measures of physical activity and hearing in African Americans: The Jackson Heart Study.

PubMed

Haas, Patrick J; Bishop, Charles E; Gao, Yan; Griswold, Michael E; Schweinfurth, John M

2016-10-01

To evaluate the relationships among measures of physical activity and hearing in the Jackson Heart Study. Prospective cohort study. We assessed hearing on 1,221 Jackson Heart Study participants who also had validated physical activity questionnaire data on file. Hearing thresholds were measured across frequency octaves from 250 to 8,000 Hz, and various frequency pure-tone averages (PTAs) were constructed, including PTA4 (average of 500, 1,000, 2,000, and 4,000 Hz), PTA-high (average of 4,000 and 8,000 Hz), PTA-mid (average of 1,000 and 2,000 Hz), and PTA-low (average of 250 and 500 Hz). Hearing loss was defined for pure tones and pure-tone averages as >25 dB HL in either ear and averaged between the ears. Associations between physical activity and hearing were estimated using linear regression, reporting changes in decibel hearing level, and logistic regression, reporting odds ratios (OR) of hearing loss. Physical activity exhibited a statistically significant but small inverse relationship with PTA4, -0.20 dB HL per doubling of activity (95% confidence interval [CI]: -0.35, -0.04; P = .016), as well as with PTA-low and pure tones at 250, 2,000, and 4,000 Hz in adjusted models. Multivariable logistic regression modeling supported a decrease in the odds of high-frequency hearing loss among participants who reported at least some moderate weekly physical activity (PTA-high, OR: 0.69 [95% CI: 0.52, 0.92]; P = .011 and 4000 Hz, OR: 0.75 [95% CI: 0.57, 0.99]; P = .044). Our study provides further evidence that physical activity is related to better hearing; however, the clinical significance of this relationship cannot be estimated given the nature of the cross-sectional study design. 2b Laryngoscope, 126:2376-2381, 2016. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

The association between anthropometric measures and lung function in a population-based study of Canadian adults.

PubMed

Rowe, A; Hernandez, P; Kuhle, S; Kirkland, S

2017-10-01

Decreased lung function has health impacts beyond diagnosable lung disease. It is therefore important to understand the factors that may influence even small changes in lung function including obesity, physical fitness and physical activity. The aim of this study was to determine the anthropometric measure most useful in examining the association with lung function and to determine how physical activity and physical fitness influence this association. The current study used cross-sectional data on 4662 adults aged 40-79 years from the Canadian Health Measures Survey Cycles 1 and 2. Linear regression models were used to examine the association between the anthropometric and lung function measures (forced expiratory volume in 1 s [FEV 1 ] and forced vital capacity [FVC]); R 2 values were compared among models. Physical fitness and physical activity terms were added to the models and potential confounding was assessed. Models using sum of 5 skinfolds and waist circumference consistently had the highest R 2 values for FEV 1 and FVC, while models using body mass index consistently had among the lowest R 2 values for FEV 1 and FVC and for men and women. Physical activity and physical fitness were confounders of the relationships between waist circumference and the lung function measures. Waist circumference remained a significant predictor of FVC but not FEV 1 after adjustment for physical activity or physical fitness. Waist circumference is an important predictor of lung function. Physical activity and physical fitness should be considered as potential confounders of the relationship between anthropometric measures and lung function. Copyright © 2017. Published by Elsevier Ltd.

An ontology-based exploration of the concepts and relationships in the activities and participation component of the international classification of functioning, disability and health.

PubMed

Della Mea, Vincenzo; Simoncello, Andrea

2012-02-28

The International Classification of Functioning, Disability and Health (ICF) is a classification of health and health-related issues, aimed at describing and measuring health and disability at both individual and population levels. Here we discuss a preliminary qualitative and quantitative analysis of the relationships used in the Activities and Participation component of ICF, and a preliminary mapping to SUMO (Suggested Upper Merged Ontology) concepts. The aim of the analysis is to identify potential logical problems within this component of ICF, and to understand whether activities and participation might be defined more formally than in the current version of ICF. In the relationship analysis, we used four predicates among those available in SUMO for processes (Patient, Instrument, Agent, and subProcess). While at the top level subsumption was used in most cases (90%), at the lower levels the percentage of other relationships rose to 41%. Chapters were heterogeneous in the relationships used and some of the leaves of the tree seemed to represent properties or parts of the parent concept rather than subclasses. Mapping of ICF to SUMO proved partially feasible, with the activity concepts being mapped mostly (but not totally) under the IntentionalProcess concept in SUMO. On the other hand, the participation concept has not been mapped to any upper level concept. Our analysis of the relationships within ICF revealed issues related to confusion between classes and their properties, incorrect classifications, and overemphasis on subsumption, confirming what already observed by other researchers. However, it also suggested some properties for Activities that could be included in a more formal model: number of agents involved, the instrument used to carry out the activity, the object of the activity, complexity of the task, and an enumeration of relevant subtasks.

Modelling the effect of structural QSAR parameters on skin penetration using genetic programming

NASA Astrophysics Data System (ADS)

Chung, K. K.; Do, D. Q.

2010-09-01

In order to model relationships between chemical structures and biological effects in quantitative structure-activity relationship (QSAR) data, an alternative technique of artificial intelligence computing—genetic programming (GP)—was investigated and compared to the traditional method—statistical. GP, with the primary advantage of generating mathematical equations, was employed to model QSAR data and to define the most important molecular descriptions in QSAR data. The models predicted by GP agreed with the statistical results, and the most predictive models of GP were significantly improved when compared to the statistical models using ANOVA. Recently, artificial intelligence techniques have been applied widely to analyse QSAR data. With the capability of generating mathematical equations, GP can be considered as an effective and efficient method for modelling QSAR data.

The Relationships Between Modelling and Argumentation from the Perspective of the Model of Modelling Diagram

NASA Astrophysics Data System (ADS)

Cardoso Mendonça, Paula Cristina; Justi, Rosária

2013-09-01

Some studies related to the nature of scientific knowledge demonstrate that modelling is an inherently argumentative process. This study aims at discussing the relationship between modelling and argumentation by analysing data collected during the modelling-based teaching of ionic bonding and intermolecular interactions. The teaching activities were planned from the transposition of the main modelling stages that constitute the 'Model of Modelling Diagram' so that students could experience each of such stages. All the lessons were video recorded and their transcriptions supported the elaboration of case studies for each group of students. From the analysis of the case studies, we identified argumentative situations when students performed all of the modelling stages. Our data show that the argumentative situations were related to sense making, articulating and persuasion purposes, and were closely related to the generation of explanations in the modelling processes. They also show that representations are important resources for argumentation. Our results are consistent with some of those already reported in the literature regarding the relationship between modelling and argumentation, but are also divergent when they show that argumentation is not only related to the model evaluation phase.

Design, synthesis, antiviral bioactivity and three-dimensional quantitative structure-activity relationship study of novel ferulic acid ester derivatives containing quinazoline moiety.

PubMed

Wu, Zengxue; Zhang, Jian; Chen, Jixiang; Pan, Jianke; Zhao, Lei; Liu, Dengyue; Zhang, Awei; Chen, Jin; Hu, Deyu; Song, Baoan

2017-10-01

Ferulic acid and quinazoline derivatives possess good antiviral activities. In order to develop novel compounds with high antiviral activities, a series of ferulic acid ester derivatives containing quinazoline were synthesized and evaluated for their antiviral activities. Bioassays indicated that some of the compounds exhibited good antiviral activities in vivo against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV). One of the compounds demonstrated significant curative and protective activities against TMV and CMV, with EC 50 values of 162.14, 114.61 and 255.49, 138.81 mg L -1 , respectively, better than those of ningnanmycin (324.51, 168.84 and 373.88, 272.70 mg L -1 ). The values of q 2 and r 2 for comparative molecular field analysis and comparative molecular similarity index analysis in the TMV (0.508, 0.663 and 0.992, 0.930) and CMV (0.530, 0.626 and 0.997, 0.981) models presented good predictive abilities. Some of the title compounds demonstrated good antiviral activities. Three-dimensional quantitative structure-activity relationship models revealed that the antiviral activities depend on steric and electrostatic properties. These results could provide significant structural insights for the design of highly active ferulic acid derivatives. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The Developmental Pathway From Pubertal Timing to Delinquency and Sexual Activity From Early to Late Adolescence

PubMed Central

Negriff, Sonya; Elizabeth, J. Susman; Trickett, Penelope K.

2013-01-01

There is strong evidence that early pubertal timing is associated with adolescent problem behaviors. However, there has been limited investigation of the mechanisms or developmental relationships. The present study examined longitudinal models incorporating pubertal timing, delinquency, and sexual activity in a sample of 454 adolescents (9–13 years old at enrollment; 47% females). Participants were seen for three assessments approximately 1 year apart. Characteristics of friendship networks (older friends, male friends, older male friends) were examined as mediators. Structural equation modeling was used to test these associations as well as temporal relationships between sexual activity and delinquency. Results showed that early pubertal timing at Time 1 was related to more sexual activity at Time 2, which was related to higher delinquency at Time 3, a trend mediation effect. None of the friendship variables mediated these associations. Gender or maltreatment status did not moderate the meditational pathways. The results also supported the temporal sequence of sexual activity preceding increases in delinquency. These findings reveal that early maturing adolescents may actively seek out opportunities to engage in sexual activity which appears to be risk for subsequent delinquency. PMID:21191640

The developmental pathway from pubertal timing to delinquency and sexual activity from early to late adolescence.

PubMed

Negriff, Sonya; Susman, Elizabeth J; Trickett, Penelope K

2011-10-01

There is strong evidence that early pubertal timing is associated with adolescent problem behaviors. However, there has been limited investigation of the mechanisms or developmental relationships. The present study examined longitudinal models incorporating pubertal timing, delinquency, and sexual activity in a sample of 454 adolescents (9-13 years old at enrollment; 47% females). Participants were seen for three assessments approximately 1 year apart. Characteristics of friendship networks (older friends, male friends, older male friends) were examined as mediators. Structural equation modeling was used to test these associations as well as temporal relationships between sexual activity and delinquency. Results showed that early pubertal timing at Time 1 was related to more sexual activity at Time 2, which was related to higher delinquency at Time 3, a trend mediation effect. None of the friendship variables mediated these associations. Gender or maltreatment status did not moderate the meditational pathways. The results also supported the temporal sequence of sexual activity preceding increases in delinquency. These findings reveal that early maturing adolescents may actively seek out opportunities to engage in sexual activity which appears to be risk for subsequent delinquency.

Longitudinal Relationships Between Resources, Motivation, and Functioning

PubMed Central

Emery, Lisa; Neupert, Shevaun D.

2012-01-01

Objectives. We investigated how fluctuations and linear changes in health and cognitive resources influence the motivation to engage in complex cognitive activity and the extent to which motivation mediated the relationship between changing resources and cognitively demanding activities. Method. Longitudinal data from 332 adults aged 20–85 years were examined. Motivation was assessed using a composite of Need for Cognition and Personal Need for Structure and additional measures of health, sensory functioning, cognitive ability, and self-reported activity engagement. Results. Multilevel modeling revealed that age-typical changes in health, sensory functions, and ability were associated with changes in motivation, with the impact of declining health on motivation being particularly strong in older adulthood. Changes in motivation, in turn, predicted involvement in cognitive and social activities as well as changes in cognitive ability. Finally, motivation was observed to partially mediate the relationship between changes in resources and cognitively demanding activities. Discussion. Our results suggest that motivation may play an important role in determining the course of cognitive change and involvement in cognitively demanding everyday activities in adulthood. PMID:21926400

Routine activities and victimization at school: the significance of gender.

PubMed

Popp, Ann Marie; Peguero, Anthony A

2011-08-01

Routine activities theory has not fully considered the role of gender in shaping victimization and yet, the research literature clearly demonstrates that gender is associated with an individual's risk of victimization. In addition to the pervasive effect of gender on victimization, gender shapes an individual's daily routines and thus may create a gender-specific relationship with victimization. This article explores the importance of gender in understanding the relationship between student's participation in extracurricular routine activities (e.g., student government, clubs, sports, and etc.) and the risk of victimization. From the Education Longitudinal Study of 2002, a sample of 10th-grade students was drawn for analyses. Hierarchical Generalized Linear Modeling was employed to explore the role of gender in the relationship between extracurricular routine activities and victimization at school. The results reveal that students' gender indeed interacts with several of the extracurricular routine activities creating gender-specific risks of victimization. This article highlights the importance of gender in explaining victimization and suggests researchers should consider how gender may interact with other routine activities and victimization.

Design and prediction of new acetylcholinesterase inhibitor via quantitative structure activity relationship of huprines derivatives.

PubMed

Zhang, Shuqun; Hou, Bo; Yang, Huaiyu; Zuo, Zhili

2016-05-01

Acetylcholinesterase (AChE) is an important enzyme in the pathogenesis of Alzheimer's disease (AD). Comparative quantitative structure-activity relationship (QSAR) analyses on some huprines inhibitors against AChE were carried out using comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and hologram QSAR (HQSAR) methods. Three highly predictive QSAR models were constructed successfully based on the training set. The CoMFA, CoMSIA, and HQSAR models have values of r (2) = 0.988, q (2) = 0.757, ONC = 6; r (2) = 0.966, q (2) = 0.645, ONC = 5; and r (2) = 0.957, q (2) = 0.736, ONC = 6. The predictabilities were validated using an external test sets, and the predictive r (2) values obtained by the three models were 0.984, 0.973, and 0.783, respectively. The analysis was performed by combining the CoMFA and CoMSIA field distributions with the active sites of the AChE to further understand the vital interactions between huprines and the protease. On the basis of the QSAR study, 14 new potent molecules have been designed and six of them are predicted to be more active than the best active compound 24 described in the literature. The final QSAR models could be helpful in design and development of novel active AChE inhibitors.

Physical activity and calorie intake mediate the relationship from depression to body fat mass among female Mexican health workers.

PubMed

Quezada, Amado D; Macías-Waldman, Nayeli; Salmerón, Jorge; Swigart, Tessa; Gallegos-Carrillo, Katia

2017-11-17

Depression is a foremost cause of morbidity throughout the world and the prevalence of depression in women is about twice as high as men. Additionally, overweight and obesity are major global health concerns. We explored the relationship between depression and body fat, and the role of physical activity and diet as mediators of this relationship in a sample of 456 adult female Mexican health workers. Longitudinal and cross-sectional analyses using data from adult women of the Health Workers Cohort Study (HWCS) Measures of body fat mass (kg from DEXA), dietary intake (kcal from FFQ), leisure time activity (METs/wk) and depression (CES-D) were determined in two waves (2004-2006 and 2010-2011). We explored the interrelation between body fat, diet, leisure time, physical activity, and depression using a cross-lagged effects model fitted to longitudinal data. We also fitted a structural equations model to cross-sectional data with body fat as the main outcome, and dietary intake and physical activity from leisure time as mediators between depression and body fat. Baseline depression was significantly related to higher depression, higher calorie intake, and lower leisure time physical activity at follow-up. From our cross-sectional model, each standard deviation increase in the depression score was associated with an average increase of 751 ± 259 g (± standard error) in body fat through the mediating effects of calorie intake and physical activity. The results of this study show how depression may influence energy imbalance between calories consumed and calories expended, resulting in higher body fat among those with a greater depression score. Evaluating the role of mental conditions like depression in dietary and physical activity behaviors should be positioned as a key research goal for better designed and targeted public health interventions. The HealthWorkers Cohort Study (HWCS) has been approved by the Institutional IRB. Number: 2005-785-012.

2D-QSAR study of fullerene nanostructure derivatives as potent HIV-1 protease inhibitors

NASA Astrophysics Data System (ADS)

Barzegar, Abolfazl; Jafari Mousavi, Somaye; Hamidi, Hossein; Sadeghi, Mehdi

2017-09-01

The protease of human immunodeficiency virus1 (HIV-PR) is an essential enzyme for antiviral treatments. Carbon nanostructures of fullerene derivatives, have nanoscale dimension with a diameter comparable to the diameter of the active site of HIV-PR which would in turn inhibit HIV. In this research, two dimensional quantitative structure-activity relationships (2D-QSAR) of fullerene derivatives against HIV-PR activity were employed as a powerful tool for elucidation the relationships between structure and experimental observations. QSAR study of 49 fullerene derivatives was performed by employing stepwise-MLR, GAPLS-MLR, and PCA-MLR models for variable (descriptor) selection and model construction. QSAR models were obtained with higher ability to predict the activity of the fullerene derivatives against HIV-PR by a correlation coefficient (R2training) of 0.942, 0.89, and 0.87 as well as R2test values of 0.791, 0.67and 0.674 for stepwise-MLR, GAPLS-MLR, and PCA -MLR models, respectively. Leave-one-out cross-validated correlation coefficient (R2CV) and Y-randomization methods confirmed the models robustness. The descriptors indicated that the HIV-PR inhibition depends on the van der Waals volumes, polarizability, bond order between two atoms and electronegativities of fullerenes derivatives. 2D-QSAR simulation without needing receptor's active site geometry, resulted in useful descriptors mainly denoting ;C60 backbone-functional groups; and ;C60 functional groups; properties. Both properties in fullerene refer to the ligand fitness and improvement van der Waals interactions with HIV-PR active site. Therefore, the QSAR models can be used in the search for novel HIV-PR inhibitors based on fullerene derivatives.

Assessing the relationship between alcohol outlets and domestic violence: routine activities and the neighborhood environment.

PubMed

Roman, Caterina G; Reid, Shannon E

2012-01-01

Studies have consistently found a positive relationship between alcohol outlet density and assault, but only a handful of studies have examined whether outlet density has an influence on domestic violence. Using a framework based in crime opportunity theories, this study estimates spatial econometric regression models to test whether the density of alcohol outlets across neighborhoods is positively associated with police calls for service for domestic violence. Models also were developed to test whether the relationships found were consistent across time periods associated with the use of alcohol outlets (weeknights and weekends). The findings indicate that off-premise outlets were associated with a significant increase in domestic violence, but on-premise outlets (specifically restaurants and nightclubs) were associated with a decrease in domestic violence. The risk for domestic violence in areas of high densities of off-premise outlets was found to be high during the weekend but not during the weeknight, suggesting different routine activities for domestic violence offenders during the week.

His and Hers: Economic Factors and Relationship Quality in Germany

PubMed Central

Hardie, Jessica Halliday; Geist, Claudia; Lucas, Amy

2014-01-01

Research has linked economic factors to relationship quality in the United States, primarily using cross-sectional data. In the current study, 2 waves of the Panel Analysis of Intimate Relationships and Family Dynamics data (n = 2,937) were used to test the gendered association between economic factors and relationship satisfaction among young German couples. In contrast to U.S.-based studies, the findings showed striking gender differences in the association between economic factors and relationship satisfaction for Germans. In cross-sectional models, women’s relationship satisfaction was positively associated with receiving government economic support, and men’s satisfaction was positively associated with poverty status and negatively associated with being a breadwinner. Longitudinal models revealed that changes in poverty status are associated with women’s satisfaction, but men’s satisfaction remains tied to their role as family provider. These unexpected results suggest that men’s satisfaction is positively associated with a more equal division of labor market activity between partners. PMID:25045175

Adolescents' social environment and depression: social networks, extracurricular activity, and family relationship influences.

PubMed

Mason, Michael J; Schmidt, Christopher; Abraham, Anisha; Walker, Leslie; Tercyak, Kenneth

2009-12-01

The present study examined components of adolescents' social environment (social network, extracurricular activities, and family relationships) in association with depression. A total of 332 adolescents presenting for a routine medical check-up were self-assessed for social network risk (i.e., smoking habits of best male and female friends), extracurricular activity level (i.e., participation in organized sports teams, clubs, etc.), family relationship quality (i.e., cohesion and conflict), and symptoms of depression (i.e., minimal, mild, moderate/severe). Results of a forward linear regression modeling indicate that social environment components were associated with a significant proportion of the variance in adolescent depression (Adjusted R (2) = .177, p < or = .05). Specifically, adolescent females (beta = .166, p < .01) and those having more smokers in their social network (beta = .107, p < .05) presented with significantly greater depression symptoms. Conversely, adolescents who engaged in more extracurricular activities (beta = -.118, p < .05) and experienced higher quality family relationships (beta = -.368, p < .001) presented with significantly lower depressive symptoms. These findings highlight the important role that the social environment plays in adolescent depression, as well as yields new insights into socially-based intervention targets that may ameliorate adolescent depression. These intervention targets may be gender-specific, include positive social network skills training, increase adolescents' engagement in organized activities, and attend to the quality of their family relationships.

Logic Models: A Tool for Designing and Monitoring Program Evaluations. REL 2014-007

ERIC Educational Resources Information Center

Lawton, Brian; Brandon, Paul R.; Cicchinelli, Louis; Kekahio, Wendy

2014-01-01

introduction to logic models as a tool for designing program evaluations defines the major components of education programs--resources, activities, outputs, and short-, mid-, and long-term outcomes--and uses an example to demonstrate the relationships among them. This quick…

20180312 - Structure-based QSAR Models to Predict Systemic Toxicity Points of Departure (SOT)

EPA Science Inventory

Human health risk assessment associated with environmental chemical exposure is limited by the tens of thousands of chemicals with little or no experimental in vivo toxicity data. Data gap filling techniques, such as quantitative structure activity relationship (QSAR) models base...

Examining the Disability Model From the International Classification of Functioning, Disability, and Health Using a Large Data Set of Community-Dwelling Malaysian Older Adults

PubMed Central

Loke, Seng Cheong; Lim, Wee Shiong; Someya, Yoshiko; Hamid, Tengku A.; Nudin, Siti S. H.

2015-01-01

Objective: This study examines the International Classification of Functioning, Disability, and Health model (ICF) using a data set of 2,563 community-dwelling elderly with disease-independent measures of mobility, physical activity, and social networking, to represent ICF constructs. Method: The relationship between chronic disease and disability (independent and dependent variables) was examined using logistic regression. To demonstrate variability in activity performance with functional impairment, graphing was used. The relationship between functional impairment, activity performance, and social participation was examined graphically and using ANOVA. The impact of cognitive deficits was quantified through stratifying by dementia. Results: Disability is strongly related to chronic disease (Wald 25.5, p < .001), functional impairment with activity performance (F = 34.2, p < .001), and social participation (F= 43.6, p < .001). With good function, there is considerable variability in activity performance (inter-quartile range [IQR] = 2.00), but diminishes with high impairment (IQR = 0.00) especially with cognitive deficits. Discussion: Environment modification benefits those with moderate functional impairment, but not with higher grades of functional loss. PMID:26472747

An experience sampling study of learning, affect, and the demands control support model.

PubMed

Daniels, Kevin; Boocock, Grahame; Glover, Jane; Holland, Julie; Hartley, Ruth

2009-07-01

The demands control support model (R. A. Karasek & T. Theorell, 1990) indicates that job control and social support enable workers to engage in problem solving. In turn, problem solving is thought to influence learning and well-being (e.g., anxious affect, activated pleasant affect). Two samples (N = 78, N = 106) provided data up to 4 times per day for up to 5 working days. The extent to which job control was used for problem solving was assessed by measuring the extent to which participants changed aspects of their work activities to solve problems. The extent to which social support was used to solve problems was assessed by measuring the extent to which participants discussed problems to solve problems. Learning mediated the relationship between changing aspects of work activities to solve problems and activated pleasant affect. Learning also mediated the relationship between discussing problems to solve problems and activated pleasant affect. The findings indicated that how individuals use control and support to respond to problem-solving demands is associated with organizational and individual phenomena, such as learning and affective well-being.

PREDICTING THE ADSORPTION CAPACITY OF ACTIVATED CARBON FOR ORGANIC CONTAMINANTS FROM ADSORBENT AND ADSORBATE PROPERTIES

EPA Science Inventory

A quantitative structure-property relationship (QSPR) was developed and combined with the Polanyi-Dubinin-Manes model to predict adsorption isotherms of emerging contaminants on activated carbons with a wide range of physico-chemical properties. Affinity coefficients (β_l

Occupational Characteristics and Marital Leisure Involvement.

ERIC Educational Resources Information Center

Crawford, Duane W.

1999-01-01

Results of a study that examined the relationship between husbands' and wives' (n=66) occupational characteristics, their extent of their involvement in different types of leisure activities, and whether they engaged in these activities together revealed no consistent support for any models but indicated that wives' characteristics were important…

Identifying Metabolically Active Chemicals Using a Consensus Quantitative Structure Activity Relationship Model for Estrogen Receptor Binding

EPA Science Inventory

Traditional toxicity testing provides insight into the mechanisms underlying toxicological responses but requires a high investment in a large number of resources. The new paradigm of testing approaches involves rapid screening studies able to evaluate thousands of chemicals acro...

The effects of physically active leisure on stress-health relationships.

PubMed

Iwasaki, Y; Zuzanek, J; Mannell, R C

2001-01-01

In this article, the effects of physically active leisure on the relationships between stress and health are examined using structural equation modeling (SEM). The analyses are based on data from Canada's 1994 National Population Health Survey (n = 17,626). Overall, physically active leisure was found to directly contribute to higher levels of physical health and wellbeing, and lower levels of mental ill-health among Canadians. When the respondents experienced higher levels of chronic stress, life event stress, and/or work stress, involvement in physically active leisure appeared to help them maintain good health and wellbeing. Also, higher levels of participation in physically active leisure helped paid workers suppress levels of work stress. Agencies involved in health promotion and lifestyle intervention should give greater consideration to physically active leisure. As a significant component of an active lifestyle, physically active leisure can contribute to better health, and provide a valuable resource for coping with stress.

The Role of the Lateral Intraparietal Area in (the Study of) Decision Making.

PubMed

Huk, Alexander C; Katz, Leor N; Yates, Jacob L

2017-07-25

Over the past two decades, neurophysiological responses in the lateral intraparietal area (LIP) have received extensive study for insight into decision making. In a parallel manner, inferred cognitive processes have enriched interpretations of LIP activity. Because of this bidirectional interplay between physiology and cognition, LIP has served as fertile ground for developing quantitative models that link neural activity with decision making. These models stand as some of the most important frameworks for linking brain and mind, and they are now mature enough to be evaluated in finer detail and integrated with other lines of investigation of LIP function. Here, we focus on the relationship between LIP responses and known sensory and motor events in perceptual decision-making tasks, as assessed by correlative and causal methods. The resulting sensorimotor-focused approach offers an account of LIP activity as a multiplexed amalgam of sensory, cognitive, and motor-related activity, with a complex and often indirect relationship to decision processes. Our data-driven focus on multiplexing (and de-multiplexing) of various response components can complement decision-focused models and provides more detailed insight into how neural signals might relate to cognitive processes such as decision making.

A mechanistic stress model of protein evolution accounts for site-specific evolutionary rates and their relationship with packing density and flexibility

PubMed Central

2014-01-01

Background Protein sites evolve at different rates due to functional and biophysical constraints. It is usually considered that the main structural determinant of a site’s rate of evolution is its Relative Solvent Accessibility (RSA). However, a recent comparative study has shown that the main structural determinant is the site’s Local Packing Density (LPD). LPD is related with dynamical flexibility, which has also been shown to correlate with sequence variability. Our purpose is to investigate the mechanism that connects a site’s LPD with its rate of evolution. Results We consider two models: an empirical Flexibility Model and a mechanistic Stress Model. The Flexibility Model postulates a linear increase of site-specific rate of evolution with dynamical flexibility. The Stress Model, introduced here, models mutations as random perturbations of the protein’s potential energy landscape, for which we use simple Elastic Network Models (ENMs). To account for natural selection we assume a single active conformation and use basic statistical physics to derive a linear relationship between site-specific evolutionary rates and the local stress of the mutant’s active conformation. We compare both models on a large and diverse dataset of enzymes. In a protein-by-protein study we found that the Stress Model outperforms the Flexibility Model for most proteins. Pooling all proteins together we show that the Stress Model is strongly supported by the total weight of evidence. Moreover, it accounts for the observed nonlinear dependence of sequence variability on flexibility. Finally, when mutational stress is controlled for, there is very little remaining correlation between sequence variability and dynamical flexibility. Conclusions We developed a mechanistic Stress Model of evolution according to which the rate of evolution of a site is predicted to depend linearly on the local mutational stress of the active conformation. Such local stress is proportional to LPD, so that this model explains the relationship between LPD and evolutionary rate. Moreover, the model also accounts for the nonlinear dependence between evolutionary rate and dynamical flexibility. PMID:24716445

The relationship between vigorous physical activity and juvenile delinquency: a mediating role for self-esteem?

PubMed

Faulkner, Guy E J; Adlaf, Edward M; Irving, Hyacinth M; Allison, Kenneth R; Dwyer, John J M; Goodman, Jack

2007-04-01

Many policy-related reviews of the potential social value of sport and physical activity list the prevention of juvenile delinquency. We examined the relationships among vigorous physical activity, self-esteem, and delinquent behavior among adolescents in a large cross-sectional survey of Ontario adolescents. Data are based on questionnaires from 3,796 students (range 11-20 years) derived from the 2005 Ontario Student Drug Use Survey. Negative binominal regression methods were used to estimate both additive and interactive models predicting delinquent behavior. Vigorous physical activity was positively associated with delinquent behavior; however, this pattern of association was observed only among male adolescents. There was no evidence of a mediating role for self-esteem. Our findings suggest that physical activity is not the solution for reducing juvenile delinquency.

A Novel Two-Step Hierarchial Quantitative Structure-Activity ...

EPA Pesticide Factsheets

Background: Accurate prediction of in vivo toxicity from in vitro testing is a challenging problem. Large public–private consortia have been formed with the goal of improving chemical safety assessment by the means of high-throughput screening. Methods and results: A database containing experimental cytotoxicity values for in vitro half-maximal inhibitory concentration (IC50) and in vivo rodent median lethal dose (LD50) for more than 300 chemicals was compiled by Zentralstelle zur Erfassung und Bewertung von Ersatz- und Ergaenzungsmethoden zum Tierversuch (ZEBET ; National Center for Documentation and Evaluation of Alternative Methods to Animal Experiments) . The application of conventional quantitative structure–activity relationship (QSAR) modeling approaches to predict mouse or rat acute LD50 values from chemical descriptors of ZEBET compounds yielded no statistically significant models. The analysis of these data showed no significant correlation between IC50 and LD50. However, a linear IC50 versus LD50 correlation could be established for a fraction of compounds. To capitalize on this observation, we developed a novel two-step modeling approach as follows. First, all chemicals are partitioned into two groups based on the relationship between IC50 and LD50 values: One group comprises compounds with linear IC50 versus LD50 relationships, and another group comprises the remaining compounds. Second, we built conventional binary classification QSAR models t

Annual and seasonal tornado activity in the United States and the global wind oscillation

NASA Astrophysics Data System (ADS)

Moore, Todd W.

2018-06-01

Previous studies have searched for relationships between tornado activity and atmospheric teleconnections to provide insight on the relationship between tornadoes, their environments, and larger scale patterns in the climate system. Knowledge of these relationships is practical because it can improve seasonal and sub-seasonal predictions of tornado probability and, therefore, help mitigate tornado-related losses. This study explores the relationships between the annual and seasonal tornado activity in the United States and the Global Wind Oscillation. Time series herein show that phases of the Global Wind Oscillation, and atmospheric angular momentum anomalies, vary over a period of roughly 20-25 years. Rank correlations indicate that tornado activity is weakly correlated with phases 2, 3, and 4 (positive) and 6, 7, and 8 (negative) of the Global Wind Oscillation in winter, spring, and fall. The correlation is not as clear in summer or at the annual scale. Non-parametric Mann-Whitney U tests indicate that winters and springs with more phase 2, 3, and 4 and fewer phase 6, 7, and 8 days tend to have more tornadoes. Lastly, logistic regression models indicate that winters and springs with more phase 2, 3, and 4 days have greater likelihoods of having more than normal tornado activity. Combined, these analyses suggest that seasons with more low atmospheric angular momentum days, or phase 2, 3, and 4 days, tend to have greater tornado activity than those with fewer days, and that this relationship is most evident in winter and spring.

Annual and seasonal tornado activity in the United States and the global wind oscillation

NASA Astrophysics Data System (ADS)

Moore, Todd W.

2017-08-01

Previous studies have searched for relationships between tornado activity and atmospheric teleconnections to provide insight on the relationship between tornadoes, their environments, and larger scale patterns in the climate system. Knowledge of these relationships is practical because it can improve seasonal and sub-seasonal predictions of tornado probability and, therefore, help mitigate tornado-related losses. This study explores the relationships between the annual and seasonal tornado activity in the United States and the Global Wind Oscillation. Time series herein show that phases of the Global Wind Oscillation, and atmospheric angular momentum anomalies, vary over a period of roughly 20-25 years. Rank correlations indicate that tornado activity is weakly correlated with phases 2, 3, and 4 (positive) and 6, 7, and 8 (negative) of the Global Wind Oscillation in winter, spring, and fall. The correlation is not as clear in summer or at the annual scale. Non-parametric Mann-Whitney U tests indicate that winters and springs with more phase 2, 3, and 4 and fewer phase 6, 7, and 8 days tend to have more tornadoes. Lastly, logistic regression models indicate that winters and springs with more phase 2, 3, and 4 days have greater likelihoods of having more than normal tornado activity. Combined, these analyses suggest that seasons with more low atmospheric angular momentum days, or phase 2, 3, and 4 days, tend to have greater tornado activity than those with fewer days, and that this relationship is most evident in winter and spring.

Developmental coordination disorder, generalized self-efficacy toward physical activity, and participation in organized and free play activities.

PubMed

Cairney, John; Hay, John A; Faught, Brent E; Wade, Terrance J; Corna, Laurie; Flouris, Andreas

2005-10-01

To test a theoretical model linking developmental coordination disorder (DCD) to reduced physical activity (PA) through the mediating influence of generalized self-efficacy regarding PA. This was a cross-sectional investigation of students in grades 4 through 8 from 5 elementary schools in the Niagara region of Ontario, Canada (n=590). Motor proficiency was evaluated using the short-form Bruininks-Oseretsky Test of Motor Proficiency. Generalized self-efficacy was assessed using the Children's Self-Perceptions of Adequacy in and Predilection for Physical Activity scale, and PA levels were evaluated using a 61-item Participation Questionnaire. Structural equation modeling was used to test the influence of generalized self-efficacy on the relationship between DCD and PA. In this sample, 7.5% (n=44) of the children met the requirements for probable DCD. The effect of DCD on PA was mediated by generalized self-efficacy. In this model, 28% of the variance in children's PA was predicted by generalized self-efficacy and DCD. Our results suggest that children with DCD are less likely to be physically active and that generalized self-efficacy can account for a considerable proportion of this relationship. The implications for appropriate interventions to increase PA among children with DCD are discussed.

Population Genetic-Based Pharmacokinetic Modeling of Methadone and its Relationship with the QTc Interval in Opioid-Dependent Patients.

PubMed

Csajka, Chantal; Crettol, Séverine; Guidi, Monia; Eap, Chin B

2016-12-01

Methadone is a μ-opioid agonist widely used for the treatment of pain, and for detoxification or maintenance treatment in opioid addiction. It has been shown to exhibit large pharmacokinetic variability and concentration-QTc relationships. In this study we investigated the relative influence of genetic polymorphism and other variables on the dose concentration-QTc relationship. A population model for methadone enantiomers in 251 opioid-dependent patients was developed using non-linear mixed effect modeling (NONMEM ® ). Various models were tested to characterize the pharmacokinetics of (R)- and (S)-methadone and the pharmacokinetic-pharmacodynamic relationship, while including demographics, physiological conditions, co-medications, and genetic variants as covariates. Model-based simulations were performed to assess the relative increase in QTc with dose upon stratification according to genetic polymorphisms involved in methadone disposition. A two-compartment model with first-order absorption and lag time provided the best model fit for (R)- and (S)-methadone pharmacokinetics. (S)-methadone clearance was influenced by cytochrome P450 (CYP) 2B6 activity, ABCB1 3435C>T, and α-1 acid glycoprotein level, while (R)-methadone clearance was influenced by CYP2B6 activity, POR*28, and CYP3A4*22. A linear model described the methadone concentration-QTc relationship, with a mean QTc increase of 9.9 ms and 19.2 ms per 1000 ng/ml of (R)- and (S)-methadone, respectively. Simulations with different methadone doses up to 240 mg/day showed that <8 % of patients presented with a QTc interval above 450 ms; however, this might reach 12 to 18 % for (R)- and (S)-methadone, respectively, in patients with a genetic status associated with a decreased methadone elimination at doses exceeding 240 mg/day. Risk factor assessment, electrocardiogram monitoring, and therapeutic drug monitoring are beneficial to optimize treatment in methadone patients, especially for those who have low levels despite high methadone doses, or who are at risk of overdosing.

Linear and non-linear quantitative structure-activity relationship models on indole substitution patterns as inhibitors of HIV-1 attachment.

PubMed

Nirouei, Mahyar; Ghasemi, Ghasem; Abdolmaleki, Parviz; Tavakoli, Abdolreza; Shariati, Shahab

2012-06-01

The antiviral drugs that inhibit human immunodeficiency virus (HIV) entry to the target cells are already in different phases of clinical trials. They prevent viral entry and have a highly specific mechanism of action with a low toxicity profile. Few QSAR studies have been performed on this group of inhibitors. This study was performed to develop a quantitative structure-activity relationship (QSAR) model of the biological activity of indole glyoxamide derivatives as inhibitors of the interaction between HIV glycoprotein gp120 and host cell CD4 receptors. Forty different indole glyoxamide derivatives were selected as a sample set and geometrically optimized using Gaussian 98W. Different combinations of multiple linear regression (MLR), genetic algorithms (GA) and artificial neural networks (ANN) were then utilized to construct the QSAR models. These models were also utilized to select the most efficient subsets of descriptors in a cross-validation procedure for non-linear log (1/EC50) prediction. The results that were obtained using GA-ANN were compared with MLR-MLR and MLR-ANN models. A high predictive ability was observed for the MLR, MLR-ANN and GA-ANN models, with root mean sum square errors (RMSE) of 0.99, 0.91 and 0.67, respectively (N = 40). In summary, machine learning methods were highly effective in designing QSAR models when compared to statistical method.

Is the relationship between the built environment and physical activity moderated by perceptions of crime and safety?

PubMed

Bracy, Nicole L; Millstein, Rachel A; Carlson, Jordan A; Conway, Terry L; Sallis, James F; Saelens, Brian E; Kerr, Jacqueline; Cain, Kelli L; Frank, Lawrence D; King, Abby C

2014-02-24

Direct relationships between safety concerns and physical activity have been inconsistently patterned in the literature. To tease out these relationships, crime, pedestrian, and traffic safety were examined as moderators of built environment associations with physical activity. Exploratory analyses used two cross-sectional studies of 2068 adults ages 20-65 and 718 seniors ages 66+ with similar designs and measures. The studies were conducted in the Baltimore, Maryland-Washington, DC and Seattle-King County, Washington regions during 2001-2005 (adults) and 2005-2008 (seniors). Participants were recruited from areas selected to sample high- and low- income and walkability. Independent variables perceived crime, traffic, and pedestrian safety were measured using scales from validated instruments. A GIS-based walkability index was calculated for a street-network buffer around each participant's home address. Outcomes were total physical activity measured using accelerometers and transportation and leisure walking measured with validated self-reports (IPAQ-long). Mixed effects regression models were conducted separately for each sample. Of 36 interactions evaluated across both studies, only 5 were significant (p< .05). Significant interactions did not consistently support a pattern of highest physical activity when safety was rated high and environments were favorable. There was not consistent evidence that safety concerns reduced the beneficial effects of favorable environments on physical activity. Only pedestrian safety showed evidence of a consistent main effect with physical activity outcomes, possibly because pedestrian safety items (e.g., crosswalks, sidewalks) were not as subjective as those on the crime and traffic safety scales. Clear relationships between crime, pedestrian, and traffic safety with physical activity levels remain elusive. The development of more precise safety variables and the use of neighborhood-specific physical activity outcomes may help to elucidate these relationships.

Is the relationship between the built environment and physical activity moderated by perceptions of crime and safety?

PubMed Central

2014-01-01

Background Direct relationships between safety concerns and physical activity have been inconsistently patterned in the literature. To tease out these relationships, crime, pedestrian, and traffic safety were examined as moderators of built environment associations with physical activity. Methods Exploratory analyses used two cross-sectional studies of 2068 adults ages 20–65 and 718 seniors ages 66+ with similar designs and measures. The studies were conducted in the Baltimore, Maryland-Washington, DC and Seattle-King County, Washington regions during 2001–2005 (adults) and 2005–2008 (seniors). Participants were recruited from areas selected to sample high- and low- income and walkability. Independent variables perceived crime, traffic, and pedestrian safety were measured using scales from validated instruments. A GIS-based walkability index was calculated for a street-network buffer around each participant’s home address. Outcomes were total physical activity measured using accelerometers and transportation and leisure walking measured with validated self-reports (IPAQ-long). Mixed effects regression models were conducted separately for each sample. Results Of 36 interactions evaluated across both studies, only 5 were significant (p < .05). Significant interactions did not consistently support a pattern of highest physical activity when safety was rated high and environments were favorable. There was not consistent evidence that safety concerns reduced the beneficial effects of favorable environments on physical activity. Only pedestrian safety showed evidence of a consistent main effect with physical activity outcomes, possibly because pedestrian safety items (e.g., crosswalks, sidewalks) were not as subjective as those on the crime and traffic safety scales. Conclusions Clear relationships between crime, pedestrian, and traffic safety with physical activity levels remain elusive. The development of more precise safety variables and the use of neighborhood-specific physical activity outcomes may help to elucidate these relationships. PMID:24564971

Modeling the relationship between physical activity and quality of life in menopausal-aged women: a cross-sectional study.

PubMed

Javadivala, Zeinab; Kousha, Ahmad; Allahverdipour, Hamid; Asghari Jafarabadi, Mohammad; Tallebian, Hossein

2013-09-17

The purpose of the present study was (a) to assess the relationship between physical activity and the intensity and duration of menopausal symptoms, (b) to investigate the relationship between physical activity and the four domains of health-related quality of life (HRQOL) and (c) to assess the relationship between physical activity and chronic diseases. This descriptive-analytical study that was conducted in Tabriz City, Iran. Data were collected in 2012 by personal home-based interviews, using structured questionnaires. All participants (n= 273), who were middle-aged (age range of 40-60 yr) were recruited from two of the 25 urban health service centers' clients, by clustered random sampling allocation. There was a positive significant relationship between Psychological, Social, and Environmental domains of HRQOL with physical activity (P<0.001). In addition, a negative significant relation was found between somatic complaints including sexual problems (P< 0.017) and vaginal dryness (P<0.030) as well as joint-muscular discomfort (P<0.018), and the level of physical activity. Diabetic (P<0.047) and women with history of heart disease (P<0.040) performed 2.670 and 3.548 hours more than who were not. Regular physical activity would be effective in decreasing menopausal symptoms as well as improving healthy aging and also physical activity promotion as a part of healthy life style promotion programs needs to be improved in communities where women are physically inactive. In addition, women need to be informed about importance of physical activity on their life which it leads to feel healthy aging and pre and post- menopausal stages.

The Communication, Awareness, Relationships and Empowerment (C.A.R.E.) Model: An Effective Tool for Engaging Urban Communities in Community-Based Participatory Research.

PubMed

Ceasar, Joniqua; Peters-Lawrence, Marlene H; Mitchell, Valerie; Powell-Wiley, Tiffany M

2017-11-21

Little is known about recruitment methods for racial/ethnic minority populations from resource-limited areas for community-based health and needs assessments, particularly assessments that incorporate mobile health (mHealth) technology for characterizing physical activity and dietary intake. We examined whether the Communication, Awareness, Relationships and Empowerment (C.A.R.E.) model could reduce challenges recruiting and retaining participants from faith-based organizations in predominantly African American Washington, D.C. communities for a community-based assessment. Employing C.A.R.E. model elements, our diverse research team developed partnerships with churches, health organizations, academic institutions and governmental agencies. Through these partnerships, we cultivated a visible presence at community events, provided cardiovascular health education and remained accessible throughout the research process. Additionally, these relationships led to the creation of a community advisory board (CAB), which influenced the study's design, implementation, and dissemination. Over thirteen months, 159 individuals were recruited for the study, 99 completed the initial assessment, and 81 used mHealth technology to self-monitor physical activity over 30 days. The culturally and historically sensitive C.A.R.E. model strategically engaged CAB members and study participants. It was essential for success in recruitment and retention of an at-risk, African American population and may be an effective model for researchers hoping to engage racial/ethnic minority populations living in urban communities.

Vigorous physical activity, mental health, perceived stress, and socializing among college students.

PubMed

Vankim, Nicole A; Nelson, Toben F

2013-01-01

To examine cross-sectional associations between vigorous physical activity, mental health, perceived stress, and socializing among 4-year college students. A national cross-sectional sample of 4-year colleges in the United States. Ninety-four 4-year colleges in the United States. A total of 14,804 undergraduate students. Self-report vigorous physical activity, perceived stress (measured using the Cohen Perceived Stress Scale), mental health (measured using the SF-36), and socializing (assessed using self-report number of friends and hours spent socializing). Logistic regression models accounting for clustering within schools were estimated to examine the association between vigorous physical activity, mental health, perceived stress, and socializing. Adjusted models included high school vigorous physical activity and sociodemographic characteristics. Students who met vigorous physical activity recommendations were less likely to report poor mental health (adjusted odds ratio [OR]: .79; 95% confidence interval [CI]: .69, .90) and perceived stress (adjusted OR: .75; 95% CI: .67, .83) than students who did not meet recommendations. In addition, socializing partially mediated the relationship between vigorous physical activity, mental health, and perceived stress; however, race and sex did not moderate the relationship. Interventions aiming to improve mental well-being of college students should also consider promoting physical activity. At least some of the positive benefits of physical activity may arise from social interactions.

The relationship between actual motor competence and physical activity in children: mediating roles of perceived motor competence and health-related physical fitness.

PubMed

Khodaverdi, Zeinab; Bahram, Abbas; Stodden, David; Kazemnejad, Anoshirvan

2016-08-01

The purpose of this study was to investigate whether perceived motor competence and components of health-related physical fitness mediated the relationship between actual motor competence and physical activity in 8- to 9-year-old Iranian girls. A convenience sample of 352 girls (mean age = 8.7, SD = 0.3 years) participated in the study. Actual motor competence, perceived motor competence and children's physical activity were assessed using the Test of Gross Motor Development-2, the physical ability sub-scale of Marsh's Self-Description Questionnaire and Physical Activity Questionnaire for Older Children, respectively. Body mass index, the 600 yard run/walk, curl-ups, push-ups, and back-saver sit and reach tests assessed health-related physical fitness. Preacher & Hayes (2004) bootstrap method was used to assess the potential mediating effects of fitness and perceived competence on the direct relationship between actual motor competence and physical activity. Regression analyses revealed that aerobic fitness (b = .28, 95% CI = [.21, .39]), as the only fitness measure, and perceived competence (b = .16, 95% CI = [.12, .32]) were measures that mediated the relationship between actual motor competence and physical activity with the models. Development of strategies targeting motor skill acquisition, children's self-perceptions of competence and cardiorespiratory fitness should be targeted to promote girls' moderate-to-vigorous physical activity.

Correlation of tissue concentrations of the pyrethroid bifenthrin with neurotoxicity in the rat.

PubMed

Scollon, Edward J; Starr, James M; Crofton, Kevin M; Wolansky, Marcelo J; DeVito, Michael J; Hughes, Michael F

2011-11-28

The potential for human exposure to pyrethroid pesticides has prompted pharmacodynamic and pharmacokinetic research to better characterize risk. This work tested the hypothesis that blood and brain concentrations of the pyrethroid bifenthrin are predictive of neurotoxic effects. Adult male Long Evans rats received a single oral dose of bifenthrin dissolved in corn oil. Using figure-eight mazes, motor activity was measured for 1h at 4- and 7-h following exposure to bifenthrin (0-16mg/kg or 0-9mg/kg, respectively; n=4-8/group). Whole blood and brains were collected immediately following motor activity assays. Bifenthrin concentrations in blood and brain were quantified using HPLC/MS/MS. Bifenthrin exposure decreased motor activity from 20% to 70% in a dose-dependent manner at both time points. The relationship between motor activity data and administered dose, and blood and brain bifenthrin concentrations were described using a sigmoidal E(max) model. The relationships between motor activity and administered dose or blood concentrations were different between the 4- and 7-h time points. The relationship between motor activity and brain concentration was not significantly different between the two time points. These data suggest that momentary brain concentration of bifenthrin may be a more precise dose metric for predicting behavioral effects because the relationship between brain concentration and locomotor activity is independent of the time of exposure. Published by Elsevier Ireland Ltd.

Cross-sectional and prospective relationship between physical activity and chronic diseases in European older adults.

PubMed

Marques, Adilson; Peralta, Miguel; Martins, João; de Matos, Margarida Gaspar; Brownson, Ross C

2017-05-01

This study examined the relationship between physical activity (PA) and chronic diseases in European older adults, using a prospective analysis with data from 2011 and 2013. Participants were 37,524 older adults (16,204 men) who responded to the fourth (in 2011) and fifth (in 2013) wave of SHARE project, from 13 European countries. Participants' answers to interview questions about the presence of chronic conditions and PA. The cross-sectional and prospective association between PA and the number of chronic diseases was assessed using general linear models. Among men and women, moderate or vigorous physical activity (MVPA) in 2011 was associated with fewer reported chronic diseases in 2011 and 2013. In prospective analysis, MVPA in 2011 was inversely associated with the number of chronic diseases in 2013 in the unadjusted model. In the adjusted model MVPA more than once a week remained as a significant predictor of fewer chronic diseases. PA should be prescribed to older adults in order to prevent and reduce the number of chronic diseases, and, when possible, vigorous intensity PA should be recommended.

On the interannual oscillations in the northern temperate total ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krzyscin, J.W.

1994-07-01

The interannual variations in total ozone are studied using revised Dobson total ozone records (1961-1990) from 17 stations located within the latitude band 30 deg N - 60 deg N. To obtain the quasi-biennial oscillation (QBO), El Nino-Southern Oscillation (ENSO), and 11-year solar cycle manifestation in the `northern temperate` total ozone data, various multiple regression models are constructed by the least squares fitting to the observed ozone. The statistical relationships between the selected indices of the atmospheric variabilities and total ozone are described in the linear and nonlinear regression models. Nonlinear relationships to the predictor variables are found. That is,more » the total ozone variations are statistically modeled by nonlinear terms accounting for the coupling between QBO and ENSO, QBO and solar activity, and ENSO and solar activity. It is suggested that large reduction of total ozone values over the `northern temperate` region occurs in cold season when a strong ENSO warm event meets the west phase of the QBO during the period of high solar activity.« less

What We Know About the Brain Structure-Function Relationship.

PubMed

Batista-García-Ramó, Karla; Fernández-Verdecia, Caridad Ivette

2018-04-18

How the human brain works is still a question, as is its implication with brain architecture: the non-trivial structure–function relationship. The main hypothesis is that the anatomic architecture conditions, but does not determine, the neural network dynamic. The functional connectivity cannot be explained only considering the anatomical substrate. This involves complex and controversial aspects of the neuroscience field and that the methods and methodologies to obtain structural and functional connectivity are not always rigorously applied. The goal of the present article is to discuss about the progress made to elucidate the structure–function relationship of the Central Nervous System, particularly at the brain level, based on results from human and animal studies. The current novel systems and neuroimaging techniques with high resolutive physio-structural capacity have brought about the development of an integral framework of different structural and morphometric tools such as image processing, computational modeling and graph theory. Different laboratories have contributed with in vivo, in vitro and computational/mathematical models to study the intrinsic neural activity patterns based on anatomical connections. We conclude that multi-modal techniques of neuroimaging are required such as an improvement on methodologies for obtaining structural and functional connectivity. Even though simulations of the intrinsic neural activity based on anatomical connectivity can reproduce much of the observed patterns of empirical functional connectivity, future models should be multifactorial to elucidate multi-scale relationships and to infer disorder mechanisms.

Invasive wisteria in the Southeastern United StateS: genetic diversity, hybridization and the role of urban centers

Treesearch

Jennifer L. Trusty; Leslie R. Goertzen; Wayne C. Zipperer; B Graeme Lockaby

2007-01-01

The increasing numbers and negative impacts of invasive species have prompted research on the relationship between human activities and the success of invasive horticultural plants. In this study, we use population genetic relationships to model the escape of a common garden vine, exotic Wisteria, into natural habitats. Urban and naturalized Wisteria populations in...

Establishing a relationship between maximum torque production of isolated joints to simulate EVA ratchet push-pull maneuver: A case study

NASA Technical Reports Server (NTRS)

Pandya, Abhilash; Maida, James; Hasson, Scott; Greenisen, Michael; Woolford, Barbara

1993-01-01

As manned exploration of space continues, analytical evaluation of human strength characteristics is critical. These extraterrestrial environments will spawn issues of human performance which will impact the designs of tools, work spaces, and space vehicles. Computer modeling is an effective method of correlating human biomechanical and anthropometric data with models of space structures and human work spaces. The aim of this study is to provide biomechanical data from isolated joints to be utilized in a computer modeling system for calculating torque resulting from any upper extremity motions: in this study, the ratchet wrench push-pull operation (a typical extravehicular activity task). Established here are mathematical relationships used to calculate maximum torque production of isolated upper extremity joints. These relationships are a function of joint angle and joint velocity.

Predicting passenger seat comfort and discomfort on the basis of human, context and seat characteristics: a literature review.

PubMed

Hiemstra-van Mastrigt, Suzanne; Groenesteijn, Liesbeth; Vink, Peter; Kuijt-Evers, Lottie F M

2017-07-01

This literature review focused on passenger seat comfort and discomfort in a human-product-context interaction. The relationships between anthropometric variables (human level), activities (context level), seat characteristics (product level) and the perception of comfort and discomfort were studied through mediating variables, such as body posture, movement and interface pressure. It is concluded that there are correlations between anthropometric variables and interface pressure variables, and that this relationship is affected by body posture. The results of studies on the correlation between pressure variables and passenger comfort and discomfort are not in line with each other. Only associations were found between the other variables (e.g. activities and seat characteristics). A conceptual model illustrates the results of the review, but relationships could not be quantified due to a lack of statistical evidence and large differences in research set-ups between the reviewed papers. Practitioner Summary: This literature review set out to quantify the relationships between human, context and seat characteristics, and comfort and discomfort experience of passenger seats, in order to build a predictive model that can support seat designers and purchasers to make informed decisions. However, statistical evidence is lacking from existing literature.

Obesity, Physical Activity, and Sedentary Behavior of Youth with Learning Disabilities and ADHD

ERIC Educational Resources Information Center

Cook, Bryan G.; Li, Dongmei; Heinrich, Katie M.

2015-01-01

Obesity, physical activity, and sedentary behavior in childhood are important indicators of present and future health and are associated with school-related outcomes such as academic achievement, behavior, peer relationships, and self-esteem. Using logistic regression models that controlled for gender, age, ethnicity/race, and socioeconomic…

PREDICTING THE ADSORPTION CAPACITY OF ACTIVATED CARBON FOR EMERGING ORGANIC CONTAMINANTS FROM FUNDAMENTAL ADSORBENT AND ADSORBATE PROPERTIES - PRESENTATION

EPA Science Inventory

A quantitative structure-property relationship (QSPR) was developed and combined with the Polanyi-Dubinin-Manes model to predict adsorption isotherms of emerging contaminants on activated carbons with a wide range of physico-chemical properties. Affinity coefficients (β_l

INTER-SPECIES COMPARISONS AND SAR MODELLING OF ESTROGENICITY USING RAINBOW TROUT ER BINDING DATA

EPA Science Inventory

The U.S. EPA has been mandated to screen industrial chemicals and pesticides for potential endocrine activity. Structure-activity relationships (SARs) to predict receptor binding are being developed as a first step to rank and prioritize chemicals for testing in bioassays. First ...

Developing Interdisciplinary Units: Strategies and Examples.

ERIC Educational Resources Information Center

McDonald, Jacqueline; Czerniak, Charlene

1994-01-01

A theme of sharks is used to illustrate the process of developing interdisciplinary units for middle school instruction, including a model for teams of teachers to follow. As activities evolve, a concept map is created to illustrate relationships and integration of ideas and activities for various disciplines. (Contains 10 references.) (MKR)

Departments of Defense and Agriculture Team Up to Develop New Insecticides for Mosquito Control

DTIC Science & Technology

2010-01-01

archives of insecticide data by quantita- tive structure-activity relationship ( QSAR ) modeling to predict and synthesize new insecticides. This...blood- sucking arthropods. The key thrust of IIBBL’s approach involves QSAR -based modeling of fast-acting pyrethroid insecticides to predict and

Comparison of Global and Mode of Action-Based Models for Aquatic Toxicity

EPA Science Inventory

The ability to estimate aquatic toxicity for a wide variety of chemicals is a critical need for ecological risk assessment and chemical regulation. The consensus in the literature is that mode of action (MOA) based QSAR (Quantitative Structure Activity Relationship) models yield ...

Estimation of Physical Properties and Chemical Reactivity Parameters of Organic Compounds for Environmental Modeling by SPARC

EPA Science Inventory

Mathematical models for predicting the transport and fate of pollutants in the environment require reactivity parameter values that is value of the physical and chemical constants that govern reactivity. Although empirical structure activity relationships have been developed th...

Modeling Relationships among Learning, Attitude, Self-Perception, and Science Achievement for Grade 8 Saudi Students

ERIC Educational Resources Information Center

Tighezza, M'Hamed

2014-01-01

The purpose of the present study was to examine the validity of modeling science achievement in terms of 3 social psychological variables (school connectedness, science attitude, and active learning) and 2 self-perception variables (self-confidence and science value). Two models were tested: full mediation and partial mediation. In the…

Using the Scientific Method to Engage Mathematical Modeling: An Investigation of pi

ERIC Educational Resources Information Center

Archer, Lester A. C.; Ng, Karen E.

2016-01-01

The purpose of this paper is to explain how to use the scientific method as the framework to introduce mathematical model. Two interdisciplinary activities, targeted for students in grade 6 or grade 7, are explained to show the application of the scientific method while building a mathematical model to investigate the relationship between the…

Do non-native plant species affect the shape of productivity-diversity relationships?

USGS Publications Warehouse

Drake, J.M.; Cleland, E.E.; Horner-Devine, M. C.; Fleishman, E.; Bowles, C.; Smith, M.D.; Carney, K.; Emery, S.; Gramling, J.; Vandermast, D.B.; Grace, J.B.

2008-01-01

The relationship between ecosystem processes and species richness is an active area of research and speculation. Both theoretical and experimental studies have been conducted in numerous ecosystems. One finding of these studies is that the shape of the relationship between productivity and species richness varies considerably among ecosystems and at different spatial scales, though little is known about the relative importance of physical and biological mechanisms causing this variation. Moreover, despite widespread concern about changes in species' global distributions, it remains unclear if and how such large-scale changes may affect this relationship. We present a new conceptual model of how invasive species might modulate relationships between primary production and species richness. We tested this model using long-term data on relationships between aboveground net primary production and species richness in six North American terrestrial ecosystems. We show that primary production and abundance of non-native species are both significant predictors of species richness, though we fail to detect effects of invasion extent on the shapes of the relationship between species richness and primary production.

Alcohol Use and Crime: Findings from a Longitudinal Sample of U.S. Adolescents and Young Adults

PubMed Central

Popovici, Ioana; Homer, Jenny F.; Fang, Hai; French, Michael T.

2011-01-01

Background A positive relationship between alcohol use and criminal activity has been well documented among adults, but fewer studies explore this relationship among adolescents. Methods Using data from four waves of the National Longitudinal Study of Adolescent Health (Add Health), we examine alcohol use patterns and criminal activity from adolescence to young adulthood. Fixed-effects models partially address the potential endogeneity of alcohol use, and, because numerous studies indicate that males are more likely than females to engage in drinking and criminal activity, the analyses are segmented by gender. Results We find a strong positive relationship between alcohol consumption, the commission of crimes, and criminal victimization for both genders. Various sensitivity analyses and robustness checks support this core finding. Conclusions Our results have important policy implications, as public policy tools that aim to reduce drinking among adolescents could also reduce criminal activity. Moreover, effective alcohol abuse treatment may indirectly reduce delinquency and thus have greater long-term economic benefits than previously estimated. PMID:22168924

Alcohol use and crime: findings from a longitudinal sample of U.S. adolescents and young adults.

PubMed

Popovici, Ioana; Homer, Jenny F; Fang, Hai; French, Michael T

2012-03-01

A positive relationship between alcohol use and criminal activity has been well documented among adults, but fewer studies explore this relationship among adolescents. Using data from 4 waves of the National Longitudinal Study of Adolescent Health (Add Health), we examine alcohol use patterns and criminal activity from adolescence to young adulthood. Fixed-effects models partially address the potential endogeneity of alcohol use, and, because numerous studies indicate that males are more likely than females to engage in drinking and criminal activity, the analyses are segmented by gender. We find a strong positive relationship between alcohol consumption, the commission of crimes, and criminal victimization for both genders. Various sensitivity analyses and robustness checks support this core finding. Our results have important policy implications, as public policy tools that aim to reduce drinking among adolescents could also reduce criminal activity. Moreover, effective alcohol abuse treatment may indirectly reduce delinquency and thus have greater long-term economic benefits than previously estimated. Copyright © 2011 by the Research Society on Alcoholism.

Active and passive characteristics of muscle tone and their relationship to models of subluxation/joint dysfunction

PubMed Central

Knutson, Gary A.; Owens, Edward F.

2003-01-01

The relationship of muscles to the causes and effects of the pathophysiologic entity referred to as chiropractic subluxation or joint dysfunction is critical. Part I of this paper reviewed the complexities of skeletal muscle in regards to anatomy, active and passive tone, detection of muscle tone, neurophysiology, and how muscle function fits into a variety of subluxation/joint dysfunction models. The concluding part of the review culminates in a hypothesis to describe and explain varying degrees of muscle tone that may be encountered clinically. It is hoped that knowledge of the differing levels of muscle tone and their causes will help the clinician to better determine the underlying cause of a neuromusculoskeletal problem allowing application of necessary and proper intervention.

Small molecule non-peptide inhibitors of botulinum neurotoxin serotype E: Structure-activity relationship and a pharmacophore model.

PubMed

Kumar, Gyanendra; Agarwal, Rakhi; Swaminathan, Subramanyam

2016-09-15

Botulinum neurotoxins (BoNTs) are the most poisonous biological substance known to humans. They cause flaccid paralysis by blocking the release of acetylcholine at the neuromuscular junction. Here, we report a number of small molecule non-peptide inhibitors of BoNT serotype E. The structure-activity relationship and a pharmacophore model are presented. Although non-peptidic in nature, these inhibitors mimic key features of the uncleavable substrate peptide Arg-Ile-Met-Glu (RIME) of the SNAP-25 protein. Among the compounds tested, most of the potent inhibitors bear a zinc-chelating moiety connected to a hydrophobic and aromatic moiety through a carboxyl or amide linker. All of them show low micromolar IC50 values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metal Oxide Nanomaterial QNAR Models: Available Structural Descriptors and Understanding of Toxicity Mechanisms

PubMed Central

Ying, Jiali; Zhang, Ting; Tang, Meng

2015-01-01

Metal oxide nanomaterials are widely used in various areas; however, the divergent published toxicology data makes it difficult to determine whether there is a risk associated with exposure to metal oxide nanomaterials. The application of quantitative structure activity relationship (QSAR) modeling in metal oxide nanomaterials toxicity studies can reduce the need for time-consuming and resource-intensive nanotoxicity tests. The nanostructure and inorganic composition of metal oxide nanomaterials makes this approach different from classical QSAR study; this review lists and classifies some structural descriptors, such as size, cation charge, and band gap energy, in recent metal oxide nanomaterials quantitative nanostructure activity relationship (QNAR) studies and discusses the mechanism of metal oxide nanomaterials toxicity based on these descriptors and traditional nanotoxicity tests. PMID:28347085

Small molecule non-peptide inhibitors of botulinum neurotoxin serotype E: Structure–activity relationship and a pharmacophore model

DOE PAGES

Kumar, Gyanendra; Agarwal, Rakhi; Swaminathan, Subramanyam

2016-06-18

Botulinum neurotoxins (BoNTs) are the most poisonous biological substance known to humans. They cause flaccid paralysis by blocking the release of acetylcholine at the neuromuscular junction. Here, we report a number of small molecule non-peptide inhibitors of BoNT serotype E. In addition, the structure–activity relationship and a pharmacophore model are presented. Although non-peptidic in nature, these inhibitors mimic key features of the uncleavable substrate peptide Arg-Ile-Met-Glu (RIME) of the SNAP-25 protein. Among the compounds tested, most of the potent inhibitors bear a zinc-chelating moiety connected to a hydrophobic and aromatic moiety through a carboxyl or amide linker. All of themmore » show low micromolar IC 50 values.« less

Quantitative structure-activity relationships studies of CCR5 inhibitors and toxicity of aromatic compounds using gene expression programming.

PubMed

Shi, Weimin; Zhang, Xiaoya; Shen, Qi

2010-01-01

Quantitative structure-activity relationship (QSAR) study of chemokine receptor 5 (CCR5) binding affinity of substituted 1-(3,3-diphenylpropyl)-piperidinyl amides and ureas and toxicity of aromatic compounds have been performed. The gene expression programming (GEP) was used to select variables and produce nonlinear QSAR models simultaneously using the selected variables. In our GEP implementation, a simple and convenient method was proposed to infer the K-expression from the number of arguments of the function in a gene, without building the expression tree. The results were compared to those obtained by artificial neural network (ANN) and support vector machine (SVM). It has been demonstrated that the GEP is a useful tool for QSAR modeling. Copyright 2009 Elsevier Masson SAS. All rights reserved.

Gender Similarities and Differences in Factors Associated with Adolescent Moderate-Vigorous Physical Activity

PubMed Central

Wenthe, Phyllis J.; Janz, Kathleen F; Levy, Stephen M.

2010-01-01

This study investigated the relationship between predisposing, reinforcing, and enabling factors conceptualized within the Youth Physical Activity Promotion Model (YPAP) and moderate to vigorous physical activity (MVPA) of adolescent males and females. Specifically, self-efficacy to overcome barriers, enjoyment of physical activity; family support, peer support, perceived school climate, neighborhood safety and access to physical activity were examined. The Physical Activity Questionnaire for Adolescents (PAQ-A) and the Actigraph 7164 were used to obtain three different measures of MVPA in 205 adolescents (102 males, 103 females). Family support emerged as the most significant and consistent factor associated with the MVPA of both adolescent males and females. This relationship was noted even when different methods of measuring MVPA were employed. These findings should increase the confidence of public health officials that family support has the potential to positively alter the physical activity behavior of adolescents. PMID:19827453

Correlation between structure, retention, property, and activity of biologically relevant 1,7-bis(aminoalkyl)diazachrysene derivatives.

PubMed

Šegan, Sandra; Trifković, Jelena; Verbić, Tatjana; Opsenica, Dejan; Zlatović, Mario; Burnett, James; Šolaja, Bogdan; Milojković-Opsenica, Dušanka

2013-01-01

The physicochemical properties, retention parameters (R(M)(0)), partition coefficients (logP(OW)), and pK(a) values for a series of thirteen 1,7-bis(aminoalkyl) diazachrysene (1,7-DAAC) derivatives were determined in order to reveal the characteristics responsible for their biological behavior. The investigated compounds inhibit three unrelated pathogens (the Botulinum neurotoxin serotype A light chain (BoNT/A LC), Plasmodium falciparum malaria, and Ebola filovirus) via three different mechanisms of action. To determine the most influential factors governing the retention and activities of the investigated diazachrysenes, R(M)(0), logP(OW), and biological activity values were correlated with 2D and 3D molecular descriptors, using a partial least squares regression. The resulting quantitative structure-retention (property) relationships indicate the importance of descriptors related to the hydrophobicity of the molecules (e.g., predicted partition coefficients and hydrophobic surface area). Quantitative structure-activity relationship models for describing biological activity against the BoNT/A LC and malarial strains also include overall compound polarity, electron density distribution, and proton donor/acceptor potential. Furthermore, models for Ebola filovirus inhibition are presented qualitatively to provide insights into parameters that may contribute to the compounds' antiviral activities. Overall, the models form the basis for selecting structural features that significantly affect the compound's absorption, distribution, metabolism, excretion, and toxicity profiles. Copyright © 2012 Elsevier B.V. All rights reserved.

Building chemistry one atom at a time: An investigation of the effects of two curricula in students' understanding of covalent bonding and atomic size

NASA Astrophysics Data System (ADS)

Bull, Barbara Jeanne

Chemists have to rely on models to aid in the explanation of phenomena they experience. Instruction of atomic theory has been used as the introduction and primary model for many concepts in chemistry. Therefore, it is important for students to have a robust understanding of the different atomic models, their relationships and their limitations. Previous research has shown that students have alternative conceptions concerning their interpretation of atomic models, but there is less exploration into how students apply their understanding of atomic structure to other chemical concepts. Therefore, this research concentrated on the development of three Model Eliciting Activities to investigate the most fundamental topic of the atom and how students applied their atomic model to covalent bonding and atomic size. Along with the investigation into students' use of their atomic models, a comparison was included between a traditional chemistry curriculum using an Atoms First approach and Chemistry, Life, the Universe and Everything (CLUE), a NSF-funded general chemistry curriculum. Treatment and Control groups were employed to determine the effectiveness of the curricula in conveying the relationship between atoms, covalent bonds and atomic size. The CLUE students developed a Cloud representation on the Atomic Model Eliciting Activity and maintained this depiction through the Covalent Bonding Model Eliciting Activity. The traditional students more often illustrated the atom using a Bohr representation and continued to apply the same model to their portrayal of covalent bonding. During the analysis of the Atomic Size Model Eliciting Activity, students had difficulty fully supporting their explanation of the atomic size trend. Utilizing the beSocratic platform, an activity was designed to aid students' construction of explanations using Toulmin's Argumentation Pattern. In order to study the effectiveness of the activity, the students were asked questions relating to a four-week long investigation into the identity of an inorganic salt during their laboratory class. Students who completed the activity exhibited an improvement in their explanation of the identity of their salt's cation. After completing the activity, another question was posed about the identity of their anion. Both groups saw a decrease in the percentage of students who included reasoning in their answer; however, the activity group maintained a significantly higher percentage of responses with a reasoning than the control group.

Brief report: Association between socio-demographic factors, screen media usage and physical activity by type of day in Spanish adolescents.

PubMed

Devís-Devís, José; Peiró-Velert, Carmen; Beltrán-Carrillo, Vicente J; Tomás, José Manuel

2012-02-01

This study examined the relationship between socio-demographic factors, screen media time usage, and light, moderate and vigorous activities on weekdays and weekends. Cross-sectional data was collected from 323 Spanish adolescents (mean age 13.59 years) who completed an interview administered recall questionnaire. Structural equation models indicated that male and younger adolescents spent more time on vigorous activities at the weekend, while females and older adolescents showed a greater involvement in light activities both on weekdays and weekends. State school students reported engaging in light and vigorous activities for longer periods than private school students on weekends. TV viewing was negatively linked to vigorous activities during weekdays and to light and moderate activities on weekends. The amount of mobile phone usage, however, was positively linked to light activities during weekdays, but negatively on weekends. The negative relationship between adolescents' use of screen media (TV and mobile phone) and physical activity and its possible displacement, depending on the type of day, added useful comparable knowledge for policies promoting an active lifestyle. Further research is required to provide evidence of the causality in the observed relationships. Copyright © 2010 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Sport Education and Social Goals in Physical Education: Relationships with Enjoyment, Relatedness, and Leisure-Time Physical Activity

ERIC Educational Resources Information Center

Wallhead, Tristan L.; Garn, Alex C.; Vidoni, Carla

2013-01-01

Background: Adolescents' decisions to engage in physical activities are influenced by the social aspects of the activity, including opportunity for affiliation, being part of a team, and the social status it offers. A curriculum and instructional model that has been shown to embed the student social system within a positive program of action is…

Relationships between Health-Related Fitness Knowledge, Perceived Competence, Self- Determination, and Physical Activity Behaviors of High School Students

ERIC Educational Resources Information Center

Haslem, Liz; Wilkinson, Carol; Prusak, Keven A.; Christensen, William F.; Pennington, Todd

2016-01-01

The purpose of this study was (a) to test a hypothesized model of motivation within the context of conceptual physical education (CPE), and (b) to explore the strength and directionality of perceived competence for physical activity as a possible mediator for health-related fitness knowledge (HRFK) and physical activity behaviors. High school…

Distributed Structure Searchable Toxicity

EPA Pesticide Factsheets

The Distributed Structure Searchable Toxicity (DSSTox) online resource provides high quality chemical structures and annotations in association with toxicity data. It helps to build a data foundation for improved structure-activity relationships and predictive toxicology. DSSTox publishes summarized chemical activity representations for structure-activity modeling and provides a structure browser. This tool also houses the chemical inventories for the ToxCast and Tox21 projects.

Structure-Activity Relationship and Molecular Mechanics Reveal the Importance of Ring Entropy in the Biosynthesis and Activity of a Natural Product.

PubMed

Tran, Hai L; Lexa, Katrina W; Julien, Olivier; Young, Travis S; Walsh, Christopher T; Jacobson, Matthew P; Wells, James A

2017-02-22

Macrocycles are appealing drug candidates due to their high affinity, specificity, and favorable pharmacological properties. In this study, we explored the effects of chemical modifications to a natural product macrocycle upon its activity, 3D geometry, and conformational entropy. We chose thiocillin as a model system, a thiopeptide in the ribosomally encoded family of natural products that exhibits potent antimicrobial effects against Gram-positive bacteria. Since thiocillin is derived from a genetically encoded peptide scaffold, site-directed mutagenesis allows for rapid generation of analogues. To understand thiocillin's structure-activity relationship, we generated a site-saturation mutagenesis library covering each position along thiocillin's macrocyclic ring. We report the identification of eight unique compounds more potent than wild-type thiocillin, the best having an 8-fold improvement in potency. Computational modeling of thiocillin's macrocyclic structure revealed a striking requirement for a low-entropy macrocycle for activity. The populated ensembles of the active mutants showed a rigid structure with few adoptable conformations while inactive mutants showed a more flexible macrocycle which is unfavorable for binding. This finding highlights the importance of macrocyclization in combination with rigidifying post-translational modifications to achieve high-potency binding.

Representing Heterogeneity in Structural Relationships Among Multiple Choice Variables Using a Latent Segmentation Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garikapati, Venu; Astroza, Sebastian; Pendyala, Ram M.

Travel model systems often adopt a single decision structure that links several activity-travel choices together. The single decision structure is then used to predict activity-travel choices, with those downstream in the decision-making chain influenced by those upstream in the sequence. The adoption of a singular sequential causal structure to depict relationships among activity-travel choices in travel demand model systems ignores the possibility that some choices are made jointly as a bundle as well as the possible presence of structural heterogeneity in the population with respect to decision-making processes. As different segments in the population may adopt and follow different causalmore » decision-making mechanisms when making selected choices jointly, it would be of value to develop simultaneous equations model systems relating multiple endogenous choice variables that are able to identify population subgroups following alternative causal decision structures. Because the segments are not known a priori, they are considered latent and determined endogenously within a joint modeling framework proposed in this paper. The methodology is applied to a national mobility survey data set to identify population segments that follow different causal structures relating residential location choice, vehicle ownership, and car-share and mobility service usage. It is found that the model revealing three distinct latent segments best describes the data, confirming the efficacy of the modeling approach and the existence of structural heterogeneity in decision-making in the population. Future versions of activity-travel model systems should strive to incorporate such structural heterogeneity to better reflect varying decision processes across population subgroups.« less

Neural Population Dynamics during Reaching Are Better Explained by a Dynamical System than Representational Tuning

PubMed Central

Dann, Benjamin

2016-01-01

Recent models of movement generation in motor cortex have sought to explain neural activity not as a function of movement parameters, known as representational models, but as a dynamical system acting at the level of the population. Despite evidence supporting this framework, the evaluation of representational models and their integration with dynamical systems is incomplete in the literature. Using a representational velocity-tuning based simulation of center-out reaching, we show that incorporating variable latency offsets between neural activity and kinematics is sufficient to generate rotational dynamics at the level of neural populations, a phenomenon observed in motor cortex. However, we developed a covariance-matched permutation test (CMPT) that reassigns neural data between task conditions independently for each neuron while maintaining overall neuron-to-neuron relationships, revealing that rotations based on the representational model did not uniquely depend on the underlying condition structure. In contrast, rotations based on either a dynamical model or motor cortex data depend on this relationship, providing evidence that the dynamical model more readily explains motor cortex activity. Importantly, implementing a recurrent neural network we demonstrate that both representational tuning properties and rotational dynamics emerge, providing evidence that a dynamical system can reproduce previous findings of representational tuning. Finally, using motor cortex data in combination with the CMPT, we show that results based on small numbers of neurons or conditions should be interpreted cautiously, potentially informing future experimental design. Together, our findings reinforce the view that representational models lack the explanatory power to describe complex aspects of single neuron and population level activity. PMID:27814352

Neural Population Dynamics during Reaching Are Better Explained by a Dynamical System than Representational Tuning.

PubMed

Michaels, Jonathan A; Dann, Benjamin; Scherberger, Hansjörg

2016-11-01

Recent models of movement generation in motor cortex have sought to explain neural activity not as a function of movement parameters, known as representational models, but as a dynamical system acting at the level of the population. Despite evidence supporting this framework, the evaluation of representational models and their integration with dynamical systems is incomplete in the literature. Using a representational velocity-tuning based simulation of center-out reaching, we show that incorporating variable latency offsets between neural activity and kinematics is sufficient to generate rotational dynamics at the level of neural populations, a phenomenon observed in motor cortex. However, we developed a covariance-matched permutation test (CMPT) that reassigns neural data between task conditions independently for each neuron while maintaining overall neuron-to-neuron relationships, revealing that rotations based on the representational model did not uniquely depend on the underlying condition structure. In contrast, rotations based on either a dynamical model or motor cortex data depend on this relationship, providing evidence that the dynamical model more readily explains motor cortex activity. Importantly, implementing a recurrent neural network we demonstrate that both representational tuning properties and rotational dynamics emerge, providing evidence that a dynamical system can reproduce previous findings of representational tuning. Finally, using motor cortex data in combination with the CMPT, we show that results based on small numbers of neurons or conditions should be interpreted cautiously, potentially informing future experimental design. Together, our findings reinforce the view that representational models lack the explanatory power to describe complex aspects of single neuron and population level activity.

Directionality in the Relationship of Self-regulation, Self-efficacy, and Mood Changes in Facilitating Improved Physical Activity and Nutrition Behaviors: Extending Behavioral Theory to Improve Weight-Loss Treatment Effects.

PubMed

Annesi, James J; Vaughn, Linda L

2017-06-01

To improve understanding of directionality in the dynamic relationships among psychosocial predictors of behavioral changes associated with weight loss. In women with obesity participating in a new behavioral weight-loss treatment that emphasizes physical activity (n = 53; body mass index = 34.7 ± 3.3 kg/m 2 ), mediation and moderated-mediation models were fit to assess directionality in the self-efficacy-self-regulation change relationship and additional effects of mood change and its basis on fruit/vegetable intake and physical activity behaviors through month 6 and from months 6 to 24. Self-regulation was a stronger predictor of change in self-efficacy than vice versa. Mood change did not moderate the relationships significantly between changes in self-efficacy and/or self-regulation, and weight loss behavior. Emotional eating significantly changed mediated relationships between changes in mood and fruit/vegetable intake through month 6 (95% confidence interval, -0.05 to 0.00). Findings clarified relationships of self-efficacy, self-regulation, and mood in the prediction of weight loss behaviors, and informed behavioral treatments for improved outcomes. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

Investigation on Quantitative Structure Activity Relationships and Pharmacophore Modeling of a Series of mGluR2 Antagonists

PubMed Central

Zhang, Meng-Qi; Zhang, Xiao-Le; Li, Yan; Fan, Wen-Jia; Wang, Yong-Hua; Hao, Ming; Zhang, Shu-Wei; Ai, Chun-Zhi

2011-01-01

MGluR2 is G protein-coupled receptor that is targeted for diseases like anxiety, depression, Parkinson’s disease and schizophrenia. Herein, we report the three-dimensional quantitative structure–activity relationship (3D-QSAR) studies of a series of 1,3-dihydrobenzo[ b][1,4]diazepin-2-one derivatives as mGluR2 antagonists. Two series of models using two different activities of the antagonists against rat mGluR2, which has been shown to be very similar to the human mGluR2, (activity I: inhibition of [3H]-LY354740; activity II: mGluR2 (1S,3R)-ACPD inhibition of forskolin stimulated cAMP.) were derived from datasets composed of 137 and 69 molecules respectively. For activity I study, the best predictive model obtained from CoMFA analysis yielded a Q2 of 0.513, R2 ncv of 0.868, R2 pred = 0.876, while the CoMSIA model yielded a Q2 of 0.450, R2 ncv = 0.899, R2 pred = 0.735. For activity II study, CoMFA model yielded statistics of Q2 = 0.5, R2 ncv = 0.715, R2 pred = 0.723. These results prove the high predictability of the models. Furthermore, a combined analysis between the CoMFA, CoMSIA contour maps shows that: (1) Bulky substituents in R7, R3 and position A benefit activity I of the antagonists, but decrease it when projected in R8 and position B; (2) Hydrophilic groups at position A and B increase both antagonistic activity I and II; (3) Electrostatic field plays an essential rule in the variance of activity II. In search for more potent mGluR2 antagonists, two pharmacophore models were developed separately for the two activities. The first model reveals six pharmacophoric features, namely an aromatic center, two hydrophobic centers, an H-donor atom, an H-acceptor atom and an H-donor site. The second model shares all features of the first one and has an additional acceptor site, a positive N and an aromatic center. These models can be used as guidance for the development of new mGluR2 antagonists of high activity and selectivity. This work is the first report on 3D-QSAR modeling of these mGluR2 antagonists. All the conclusions may lead to a better understanding of the mechanism of antagonism and be helpful in the design of new potent mGluR2 antagonists. PMID:22016641

Investigation on quantitative structure activity relationships and pharmacophore modeling of a series of mGluR2 antagonists.

PubMed

Zhang, Meng-Qi; Zhang, Xiao-Le; Li, Yan; Fan, Wen-Jia; Wang, Yong-Hua; Hao, Ming; Zhang, Shu-Wei; Ai, Chun-Zhi

2011-01-01

MGluR2 is G protein-coupled receptor that is targeted for diseases like anxiety, depression, Parkinson's disease and schizophrenia. Herein, we report the three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of a series of 1,3-dihydrobenzo[ b][1,4]diazepin-2-one derivatives as mGluR2 antagonists. Two series of models using two different activities of the antagonists against rat mGluR2, which has been shown to be very similar to the human mGluR2, (activity I: inhibition of [(3)H]-LY354740; activity II: mGluR2 (1S,3R)-ACPD inhibition of forskolin stimulated cAMP.) were derived from datasets composed of 137 and 69 molecules respectively. For activity I study, the best predictive model obtained from CoMFA analysis yielded a Q(2) of 0.513, R(2) (ncv) of 0.868, R(2) (pred) = 0.876, while the CoMSIA model yielded a Q(2) of 0.450, R(2) (ncv) = 0.899, R(2) (pred) = 0.735. For activity II study, CoMFA model yielded statistics of Q(2) = 0.5, R(2) (ncv) = 0.715, R(2) (pred) = 0.723. These results prove the high predictability of the models. Furthermore, a combined analysis between the CoMFA, CoMSIA contour maps shows that: (1) Bulky substituents in R(7), R(3) and position A benefit activity I of the antagonists, but decrease it when projected in R(8) and position B; (2) Hydrophilic groups at position A and B increase both antagonistic activity I and II; (3) Electrostatic field plays an essential rule in the variance of activity II. In search for more potent mGluR2 antagonists, two pharmacophore models were developed separately for the two activities. The first model reveals six pharmacophoric features, namely an aromatic center, two hydrophobic centers, an H-donor atom, an H-acceptor atom and an H-donor site. The second model shares all features of the first one and has an additional acceptor site, a positive N and an aromatic center. These models can be used as guidance for the development of new mGluR2 antagonists of high activity and selectivity. This work is the first report on 3D-QSAR modeling of these mGluR2 antagonists. All the conclusions may lead to a better understanding of the mechanism of antagonism and be helpful in the design of new potent mGluR2 antagonists.

Fish biomarkers for environmental monitoring: An integrated model supporting enzyme activity and histopathological lesions

NASA Astrophysics Data System (ADS)

Neta, Raimunda Nonata Fortes Carvalho; Torres Junior, Audalio Rebelo

2014-10-01

We present a mathematical model describing the association between glutathione-S-transferase activity and brachial lesions in the catfish, Sciades herzbergii (Ariidae) from a polluted port. The catfish were sampled from a port known to be contaminated with heavy metals and organic compounds and from a natural reserve in São Marcos Bay, Brazil. Two biomarkers, hepatic glutathione S-transferase (GST) activity and histopathological lesions, in gills tissue were measured. The values for GST activity were modeled with the occurrence of branchial lesions by fitting a third order polynomial. Results from the mathematical model indicate that GST activity has a strong polynomial relationship with the occurrence of branchial lesions in both the wet and the dry seasons, but only at the polluted port site. The model developed in this study indicates that branchial and hepatic lesions are initiated when GST activity reaches 2.15 μmol min-1 mg protein-1. Beyond this limit, GST activity decreased to very low levels and irreversible histopathological lesions occurred. This mathematical model provides a realistic approach to analyze predictive biomarkers of environmental health status.

Real-World Usage of Educational Media Does Not Promote Parent-Child Cognitive Stimulation Activities.

PubMed

Choi, Jason H; Mendelsohn, Alan L; Weisleder, Adriana; Cates, Carolyn Brockmeyer; Canfield, Caitlin; Seery, Anne; Dreyer, Benard P; Tomopoulos, Suzy

2018-03-01

To determine whether educational media as actually used by low-income families promote parent-child cognitive stimulation activities. We performed secondary analysis of the control group of a longitudinal cohort of mother-infant dyads enrolled postpartum in an urban public hospital. Educational media exposure (via a 24-hour recall diary) and parent-child activities that may promote cognitive stimulation in the home (using StimQ) were assessed at 6, 14, 24, and 36 months. Data from 149 mother-child dyads, 93.3% Latino, were analyzed. Mean (standard deviation) educational media exposure at 6, 14, 24, and 36 months was, respectively, 25 (40), 42 (58), 39 (49), and 39 (50) minutes per day. In multilevel model analyses, prior educational media exposure had small positive relationship with subsequent total StimQ scores (β = 0.11, P = .03) but was nonsignificant (β = 0.08, P = .09) after adjusting for confounders (child: age, gender, birth order, noneducational media exposure, language; mother: age, ethnicity, marital status, country of origin, language, depressive symptoms). Educational media did predict small increases in verbal interactions and toy provision (adjusted models, respectively: β = 0.13, P = .02; β = 0.11; P = .03). In contrast, more consistent relationships were seen for models of the relationship between prior StimQ (total, verbal interactions and teaching; adjusted models, respectively: β = 0.20, P = .002; β = 0.15, P = .006; β = 0.20, P = .001) and predicted subsequent educational media. Educational media as used by this sample of low-income families does not promote cognitive stimulation activities important for early child development or activities such as reading and teaching. Copyright © 2017 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Computational ligand-based rational design: Role of conformational sampling and force fields in model development.

PubMed

Shim, Jihyun; Mackerell, Alexander D

2011-05-01

A significant number of drug discovery efforts are based on natural products or high throughput screens from which compounds showing potential therapeutic effects are identified without knowledge of the target molecule or its 3D structure. In such cases computational ligand-based drug design (LBDD) can accelerate the drug discovery processes. LBDD is a general approach to elucidate the relationship of a compound's structure and physicochemical attributes to its biological activity. The resulting structure-activity relationship (SAR) may then act as the basis for the prediction of compounds with improved biological attributes. LBDD methods range from pharmacophore models identifying essential features of ligands responsible for their activity, quantitative structure-activity relationships (QSAR) yielding quantitative estimates of activities based on physiochemical properties, and to similarity searching, which explores compounds with similar properties as well as various combinations of the above. A number of recent LBDD approaches involve the use of multiple conformations of the ligands being studied. One of the basic components to generate multiple conformations in LBDD is molecular mechanics (MM), which apply an empirical energy function to relate conformation to energies and forces. The collection of conformations for ligands is then combined with functional data using methods ranging from regression analysis to neural networks, from which the SAR is determined. Accordingly, for effective application of LBDD for SAR determinations it is important that the compounds be accurately modelled such that the appropriate range of conformations accessible to the ligands is identified. Such accurate modelling is largely based on use of the appropriate empirical force field for the molecules being investigated and the approaches used to generate the conformations. The present chapter includes a brief overview of currently used SAR methods in LBDD followed by a more detailed presentation of issues and limitations associated with empirical energy functions and conformational sampling methods.

In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush).

PubMed

Ottinger, Christopher A; Honeyfield, Dale C; Densmore, Christine L; Iwanowicz, Luke R

2014-05-01

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP--biologically inactive form) to thiamine pyrophosphate (TPP--biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state. Published by Elsevier Ltd.

In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush)

USGS Publications Warehouse

Ottinger, Christopher A.; Honeyfield, Dale C.; Densmore, Christine L.; Iwanowicz, Luke R.

2014-01-01

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP – biologically inactive form) to thiamine pyrophosphate (TPP – biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state.

Circadian typology and the Alternative Five-Factor Model of personality.

PubMed

Tonetti, Lorenzo; Pascalis, Vilfredo De; Fabbri, Marco; Martoni, Monica; Russo, Paolo Maria; Natale, Vincenzo

2016-10-01

Two studies were carried out to explore the relationship between circadian typology and the Alternative Five-Factor Model of personality. In the first study, 379 participants (232 females) were administered the reduced version of the Morningness-Eveningness Questionnaire and the Zuckerman-Kuhlman Personality Questionnaire. Evening types reported higher impulsive sensation-seeking scores than morning and intermediate types, whereas morning types scored higher than evening types on activity factor. In the second study, the association between morningness and activity personality factor was verified through the objective-actigraphic monitoring of the rest-activity cycle. Actigraphy allowed us to operationalise both circadian typology, through the computing of midpoint of sleep (early values, expressed in hours and minutes, correspond to an advanced phase of the sleep/wake cycle), and activity factor by the means of motor activity recording. Fifty-one individuals (30 females) wore an actigraph on the nondominant wrist continuously for 1 week. A negative correlation was observed between midpoint of sleep and mean diurnal motor activity, demonstrating that an early phase of the sleep/wake cycle (i.e. morningness preference) was related to higher diurnal motor activity. Assessed both subjectively and objectively, the results of both studies highlight a significant relationship between morningness and activity personality factor. © 2015 International Union of Psychological Science.

Trajectories of Emotional Symptoms and Peer Relationship Problems in Children after Nuclear Disaster: Evidence from the Fukushima Health Management Survey.

PubMed

Oe, Misari; Maeda, Masaharu; Ohira, Tetsuya; Itagaki, Shuntaro; Harigane, Mayumi; Suzuki, Yuriko; Yabe, Hirooki; Yasumura, Seiji; Kamiya, Kenji; Ohto, Hitoshi

2018-01-06

The Fukushima Daiichi Nuclear Power Plant accident, which occurred in March 2011, is having long-term effects on children. We planned this study to describe the trajectories of emotional symptoms and peer relationship problems in children and to examine potential risks and protective factors over the 35 months following the accident. The sample was 11,791 children in the first to sixth elementary grades. We identified four patterns for emotional symptoms and three patterns for peer relationship problems, using group-based trajectory modelling. For emotional symptoms, female gender, experience of tsunami and nuclear plant accident, out-of-prefecture evacuees, and insufficient physical activity were associated with the very severe trajectory. In contrast, for peer relationship problems, male gender, experience of nuclear plant accident, and insufficient physical activity were associated with the very severe trajectory. Different factors might be related to the very severe trajectories of emotional symptoms and peer relationship problems.

Trajectories of Emotional Symptoms and Peer Relationship Problems in Children after Nuclear Disaster: Evidence from the Fukushima Health Management Survey

PubMed Central

Maeda, Masaharu; Itagaki, Shuntaro; Harigane, Mayumi; Suzuki, Yuriko; Yabe, Hirooki; Yasumura, Seiji; Kamiya, Kenji; Ohto, Hitoshi

2018-01-01

The Fukushima Daiichi Nuclear Power Plant accident, which occurred in March 2011, is having long-term effects on children. We planned this study to describe the trajectories of emotional symptoms and peer relationship problems in children and to examine potential risks and protective factors over the 35 months following the accident. The sample was 11,791 children in the first to sixth elementary grades. We identified four patterns for emotional symptoms and three patterns for peer relationship problems, using group-based trajectory modelling. For emotional symptoms, female gender, experience of tsunami and nuclear plant accident, out-of-prefecture evacuees, and insufficient physical activity were associated with the very severe trajectory. In contrast, for peer relationship problems, male gender, experience of nuclear plant accident, and insufficient physical activity were associated with the very severe trajectory. Different factors might be related to the very severe trajectories of emotional symptoms and peer relationship problems. PMID:29316618

Altered medial temporal activation related to local glutamate levels in subjects with prodromal signs of psychosis.

PubMed

Valli, Isabel; Stone, James; Mechelli, Andrea; Bhattacharyya, Sagnik; Raffin, Marie; Allen, Paul; Fusar-Poli, Paolo; Lythgoe, David; O'Gorman, Ruth; Seal, Marc; McGuire, Philip

2011-01-01

Both medial temporal cortical dysfunction and perturbed glutamatergic neurotransmission are regarded as fundamental pathophysiological features of psychosis. However, although animal models of psychosis suggest that these two abnormalities are interrelated, their relationship in humans has yet to be investigated. We used a combination of functional magnetic resonance imaging and magnetic resonance spectroscopy to investigate the relationship between medial temporal activation during an episodic memory task and local glutamate levels in 22 individuals with an at-risk mental state for psychosis and 14 healthy volunteers. We observed a significant between-group difference in the coupling of medial temporal activation with local glutamate levels. In control subjects, medial temporal activation during episodic encoding was positively associated with medial temporal glutamate. However, in the clinical population, medial temporal activation was reduced, and the relationship with glutamate was absent. In individuals at high risk of psychosis, medial temporal dysfunction seemed related to a loss of the normal relationship with local glutamate levels. This study provides the first evidence that links medial temporal dysfunction with the central glutamate system in humans and is consistent with evidence that drugs that modulate glutamatergic transmission might be useful in the treatment of psychosis. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Prediction-error in the context of real social relationships modulates reward system activity.

PubMed

Poore, Joshua C; Pfeifer, Jennifer H; Berkman, Elliot T; Inagaki, Tristen K; Welborn, Benjamin L; Lieberman, Matthew D

2012-01-01

The human reward system is sensitive to both social (e.g., validation) and non-social rewards (e.g., money) and is likely integral for relationship development and reputation building. However, data is sparse on the question of whether implicit social reward processing meaningfully contributes to explicit social representations such as trust and attachment security in pre-existing relationships. This event-related fMRI experiment examined reward system prediction-error activity in response to a potent social reward-social validation-and this activity's relation to both attachment security and trust in the context of real romantic relationships. During the experiment, participants' expectations for their romantic partners' positive regard of them were confirmed (validated) or violated, in either positive or negative directions. Primary analyses were conducted using predefined regions of interest, the locations of which were taken from previously published research. Results indicate that activity for mid-brain and striatal reward system regions of interest was modulated by social reward expectation violation in ways consistent with prior research on reward prediction-error. Additionally, activity in the striatum during viewing of disconfirmatory information was associated with both increases in post-scan reports of attachment anxiety and decreases in post-scan trust, a finding that follows directly from representational models of attachment and trust.

Flow of Funds Modeling for Localized Financial Markets: An Application of Spatial Price and Allocation Activity Analysis Models.

DTIC Science & Technology

1981-01-01

on modeling the managerial aspects of the firm. The second has been the application to economic theory led by ...individual portfolio optimization problems which were embedded in a larger global optimization problem. In the global problem, portfolios were linked by market ...demand quantities or be given by linear demand relationships. As in~ the source markets , the model

Illinois Programs of Study Guide: 2009

ERIC Educational Resources Information Center

Taylor, Jason L.; Kirby, Catherine L., Bragg, Debra D.; Oertle, Kathleen M.; Jankowski, Natasha A.; Khan, Sadya S.

2009-01-01

This guide begins with background information useful to understanding Illinois' framework for implementation and evaluation of Programs of Study. It starts with a visual depiction of the relationships between activity at the federal, state and local levels that evolved to the creation of Illinois' Career Cluster Model. This Model, which is based…

Relative Chemical Binding Affinities for Trout and Human Estrogen Receptor Using Different Competitive Binding Assays

EPA Science Inventory

Rainbow trout-based assays for estrogenicity are currently being used for development of predictive models based upon quantitative structure activity relationships. A predictive model based on a single species raises the question of whether this information is valid for other spe...

Collective Academic Supervision: A Model for Participation and Learning in Higher Education

ERIC Educational Resources Information Center

Nordentoft, Helle Merete; Thomsen, Rie; Wichmann-Hansen, Gitte

2013-01-01

Supervision of graduate students is a core activity in higher education. Previous research on graduate supervision focuses on individual and relational aspects of the supervisory relationship rather than collective, pedagogical and methodological aspects of the supervision process. In presenting a collective model we have developed for academic…

Abdominal obesity as a mediator of the influence of physical activity on insulin resistance in Spanish adults.

PubMed

García-Hermoso, Antonio; Martínez-Vizcaíno, Vicente; Recio-Rodriguez, Jose I; Díez-Fernández, Ana; Gómez-Marcos, Manuel A; García-Ortiz, Luis

2016-01-01

The aim of the study was to analyze the relationship between moderate-to-vigorous physical activity (MVPA) and insulin resistance (IR) in Spanish adults and to examine whether this relationship is mediated by abdominal obesity (waist circumference - WC). The cross-sectional study included 1162 healthy subjects belonging to the EVIDENT study (mean age 55.0±13.3years; 61.8% women) from six different Spanish provinces. Moderate-to-vigorous physical activity (MVPA) was measured objectively over 7days using Actigraph accelerometers, collecting data in 60-second epochs, and retaining respondents with ≥4 valid days for the analysis. The homeostasis model of assessment (HOMA-IR) was used to determine IR, and its individual components - fasting glucose and insulin - were determined using standard protocols. Linear regression models were fitted according to Baron and Kenny's procedures for mediation analysis. Fasting insulin and HOMA-IR levels were significantly worse in adults who spent fewer minutes in MVPA (first quartile≤30.1 and 22.7min/day in men and women, respectively) after adjusting for age, sex, smoking habits, drinking habits, accelerometer wear time, sedentary time, and Mediterranean diet adherence. However, when WC was added to the ANCOVA models as a covariate, the effects disappeared. Mediation analysis reported that WC acts as a full mediator in the relationship between MVPA and IR (HOMA-IR and fasting insulin). These findings show that WC plays a pivotal role in the relationship between MVPA and IR, and therefore highlights that decreasing abdominal obesity might be considered as an intermediate outcome for evaluating interventions aimed at preventing diabetes mellitus. Copyright © 2015 Elsevier Inc. All rights reserved.

Capturing the Interrelationship between Objectively Measured Physical Activity and Sedentary Behaviour in Children in the Context of Diverse Environmental Exposures.

PubMed

Katapally, Tarun R; Muhajarine, Nazeem

2015-09-07

Even though physical activity and sedentary behaviour are two distinct behaviours, their interdependent relationship needs to be studied in the same environment. This study examines the influence of urban design, neighbourhood built and social environment, and household and individual factors on the interdependent relationship between objectively measured physical activity and sedentary behaviour in children in the Canadian city of Saskatoon. Saskatoon's built environment was assessed by two validated observation tools. Neighbourhood socioeconomic variables were derived from 2006 Statistics Canada Census and 2010 G5 Census projections. A questionnaire was administered to 10-14 year old children to collect individual and household data, followed by accelerometry to collect physical activity and sedentary behaviour data. Multilevel logistic regression models were developed to understand the interrelationship between physical activity and sedentary behaviour in the context of diverse environmental exposures. A complex set of factors including denser built environment, positive peer relationships and consistent parental support influenced the interrelationship between physical activity and sedentary behaviour. In developing interventions to facilitate active living, it is not only imperative to delineate pathways through which diverse environmental exposures influence physical activity and sedentary behaviour, but also to account for the interrelationship between physical activity and sedentary behaviour.

QSAR Study of p56lck Protein Tyrosine Kinase Inhibitory Activity of Flavonoid Derivatives Using MLR and GA-PLS

PubMed Central

Fassihi, Afshin; Sabet, Razieh

2008-01-01

Quantitative relationships between molecular structure and p56lck protein tyrosine kinase inhibitory activity of 50 flavonoid derivatives are discovered by MLR and GA-PLS methods. Different QSAR models revealed that substituent electronic descriptors (SED) parameters have significant impact on protein tyrosine kinase inhibitory activity of the compounds. Between the two statistical methods employed, GA-PLS gave superior results. The resultant GA-PLS model had a high statistical quality (R2 = 0.74 and Q2 = 0.61) for predicting the activity of the inhibitors. The models proposed in the present work are more useful in describing QSAR of flavonoid derivatives as p56lck protein tyrosine kinase inhibitors than those provided previously. PMID:19325836

Filipino Americans and racism: A multiple mediation model of coping.

PubMed

Alvarez, Alvin N; Juang, Linda P

2010-04-01

Although the literature on Asian Americans and racism has been emerging, few studies have examined how coping influences one's encounters with racism. To advance the literature, the present study focused on the psychological impact of Filipino Americans' experiences with racism and the role of coping as a mediator using a community-based sample of adults (N = 199). Two multiple mediation models were used to examine the mediating effects of active, avoidance, support-seeking, and forbearance coping on the relationship between perceived racism and psychological distress and self-esteem, respectively. Separate analyses were also conducted for men and women given differences in coping utilization. For men, a bootstrap procedure indicated that active, support-seeking, and avoidance coping were mediators of the relationship between perceived racism and psychological distress. Active coping was negatively associated with psychological distress, whereas both support seeking and avoidance were positively associated with psychological distress. A second bootstrap procedure for men indicated that active and avoidance coping mediated the relationship between perceived racism and self-esteem such that active coping was positively associated with self-esteem, and avoidance was negatively associated with self-esteem. For women, only avoidance coping had a significant mediating effect that was associated with elevations in psychological distress and decreases in self-esteem. The results highlight the importance of examining the efficacy of specific coping responses to racism and the need to differentiate between the experiences of men and women. PsycINFO Database Record (c) 2010 APA, all rights reserved.

Negative influence of pKa on activation energy barrier: A case study for double proton transfer reaction in inorganic acid dimers.

PubMed

Parida, Rakesh; Giri, Santanab

2018-06-15

Strength of acid can be determined by means of pK a value. Attempts have been made to find a relationship between pK a and activation energy barrier for a double proton transfer (DPT) reaction in inorganic acid dimers. Negative influence of pK a is observed on activation energy (E a ) which is contrary to the general convention of pK a . Four different levels of theories with two different basis sets have been used to calculate the activation energy barrier of the DPT reaction in inorganic acid dimers. A model based on first and second order polynomial has been created to find the relationship between activation energy for DPT reaction. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Structure-activity relationship of antiparasitic and cytotoxic indoloquinoline alkaloids, and their tricyclic and bicyclic analogues.

PubMed

Van Baelen, Gitte; Hostyn, Steven; Dhooghe, Liene; Tapolcsányi, Pál; Mátyus, Péter; Lemière, Guy; Dommisse, Roger; Kaiser, Marcel; Brun, Reto; Cos, Paul; Maes, Louis; Hajós, György; Riedl, Zsuzsanna; Nagy, Ildikó; Maes, Bert U W; Pieters, Luc

2009-10-15

Based on the indoloquinoline alkaloids cryptolepine (1), neocryptolepine (2), isocryptolepine (3) and isoneocryptolepine (4), used as lead compounds for new antimalarial agents, a series of tricyclic and bicyclic analogues, including carbolines, azaindoles, pyrroloquinolines and pyrroloisoquinolines was synthesized and biologically evaluated. None of the bicyclic compounds was significantly active against the chloroquine-resistant strain Plasmodium falciparum K1, in contrast to the tricyclic derivatives. The tricyclic compound 2-methyl-2H-pyrido[3,4-b]indole (9), or 2-methyl-beta-carboline, showed the best in vitro activity, with an IC(50) value of 0.45 microM against P. falciparum K1, without apparent cytotoxicity against L6 cells (SI>1000). However, this compound was not active in the Plasmodium berghei mouse model. Structure-activity relationships are discussed and compared with related naturally occurring compounds.

Relationship between total and segmental bone mineral density and different domains of physical activity among children and adolescents: cross-sectional study.

PubMed

Diniz, Tiego Aparecido; Agostinete, Ricardo Ribeiro; Costa, Paulo; Saraiva, Bruna Thamyres Ciccotti; Sonvenso, Diego Kanashiro; Freitas, Ismael Forte; Fernandes, Rômulo Araujo; Christofaro, Diego Giulliano Destro

2017-01-01

This study aimed to investigate the relationship between total and segmental bone mineral density (BDM) and physical activity (PA) in different domains (school, leisure and sports) among adolescents and children. Cross-sectional study in the Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP). The study sample consisted of 173 children and adolescents (10.31 ± 1.87 years). The BMDs for the whole body (WB) and the regions of the trunk and legs were measured using dual energy X-ray absorptiometry (DXA). PA was measured using the Baecke questionnaire. A regression model was used to analyze the relationship between all the BMDs and the different domains of PA. 41.5% of the adolescents had high percentages of body fat. Regarding the comparison between physically active and insufficiently active adolescents, there were no statistically significant differences in any BMD variables (P > 0.05). The BMD of the legs showed positive relationships with the total PA (β = 0.009; P = 0.013) and sports PA (β = 0.010; P = 0.049) after insertion of the confounders. Similarly, the WB BMD showed the same relationships (total PA: β = 0.005; P = 0.045; and sports PA: β = 0.008; P = 0.049). No relationship was found between leisure and school PA and any of the BMDs (P > 0.05). The results indicated that practice of sport was related to higher BMD values, independent of sex, age and body fatness.

Design, synthesis, antiviral activity and three-dimensional quantitative structure-activity relationship study of novel 1,4-pentadien-3-one derivatives containing the 1,3,4-oxadiazole moiety.

PubMed

Gan, Xiuhai; Hu, Deyu; Li, Pei; Wu, Jian; Chen, Xuewen; Xue, Wei; Song, Baoan

2016-03-01

1,4-Pentadien-3-one and 1,3,4-oxadiazole derivatives possess good antiviral activities, and their substructure units are usually used in antiviral agent design. In order to discover novel molecules with high antiviral activities, a series of 1,4-pentadien-3-one derivatives containing the 1,3,4-oxadiazole moiety were designed and synthesised. Bioassays showed that most of the title compounds exhibited good inhibitory activities against tobacco mosaic virus (TMV) in vivo. The compound 8f possessing the best protective activity against TMV had an EC50 value of 135.56 mg L(-1) , which was superior to that of ribavirin (435.99 mg L(-1) ). Comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) techniques were used in three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of protective activities, with values of q(2) and r(2) for the CoMFA and CoMSIA models of 0.751 and 0.775 and 0.936 and 0.925 respectively. Compound 8k with higher protective activity (EC50 = 123.53 mg L(-1) ) according to bioassay was designed and synthesised on the basis of the 3D-QSAR models. Some of the title compounds displayed good antiviral activities. 3D-QSAR models revealed that the appropriate compact electron-withdrawing and hydrophobic group at the benzene ring could enhance antiviral activity. These results could provide important structural insights for the design of highly active 1,4-pentadien-3-one derivatives. © 2015 Society of Chemical Industry.

From QSAR to QSIIR: Searching for Enhanced Computational Toxicology Models

PubMed Central

Zhu, Hao

2017-01-01

Quantitative Structure Activity Relationship (QSAR) is the most frequently used modeling approach to explore the dependency of biological, toxicological, or other types of activities/properties of chemicals on their molecular features. In the past two decades, QSAR modeling has been used extensively in drug discovery process. However, the predictive models resulted from QSAR studies have limited use for chemical risk assessment, especially for animal and human toxicity evaluations, due to the low predictivity of new compounds. To develop enhanced toxicity models with independently validated external prediction power, novel modeling protocols were pursued by computational toxicologists based on rapidly increasing toxicity testing data in recent years. This chapter reviews the recent effort in our laboratory to incorporate the biological testing results as descriptors in the toxicity modeling process. This effort extended the concept of QSAR to Quantitative Structure In vitro-In vivo Relationship (QSIIR). The QSIIR study examples provided in this chapter indicate that the QSIIR models that based on the hybrid (biological and chemical) descriptors are indeed superior to the conventional QSAR models that only based on chemical descriptors for several animal toxicity endpoints. We believe that the applications introduced in this review will be of interest and value to researchers working in the field of computational drug discovery and environmental chemical risk assessment. PMID:23086837

Screening bioactive quality control markers of QiShenYiQi dripping pills based on the relationship between the ultra-high performance liquid chromatography fingerprint and vascular protective activity.

PubMed

Zhuo, Limeng; Peng, Jingjing; Zhao, Yunli; Li, Dongxiang; Xie, Xiuman; Tong, Ling; Yu, Zhiguo

2017-10-01

Traditional Chinese medicine consists of complex phytochemical constituents. Selecting appropriate analytical markers of traditional Chinese medicine is a critical step in quality control. Currently, the combination of fingerprinting and efficacy evaluation is considered as a useful method for screening active ingredients in complex mixtures. This study was designed to develop an orthogonal partial least squares model for screening bioactive quality control markers of QishenYiqi dripping pills based on the fingerprint-efficacy relationship. First, the chemical fingerprints of 49 batches of QishenYiqi dripping pill samples were established by ultra-high performance liquid chromatography coupled with a photodiode array detector. Second, ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry was exploited to systematically investigate the 36 copossessing fingerprint components in QishenYiqi dripping pills. The vascular protective activity of QishenYiqi dripping pills was determined by using a cell counting kit-8 assay. Finally, fingerprint-efficacy relationship was established by orthogonal partial least squares model. The results indicated that ten components exhibited strong correlation with vascular protective activity, and these were preliminarily screened as quality control markers. The present study provided a novel idea for the study of the pharmacodynamic material basis and quality evaluation of QishenYiqi dripping pills. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simple stochastic model for El Niño with westerly wind bursts

PubMed Central

Thual, Sulian; Majda, Andrew J.; Chen, Nan; Stechmann, Samuel N.

2016-01-01

Atmospheric wind bursts in the tropics play a key role in the dynamics of the El Niño Southern Oscillation (ENSO). A simple modeling framework is proposed that summarizes this relationship and captures major features of the observational record while remaining physically consistent and amenable to detailed analysis. Within this simple framework, wind burst activity evolves according to a stochastic two-state Markov switching–diffusion process that depends on the strength of the western Pacific warm pool, and is coupled to simple ocean–atmosphere processes that are otherwise deterministic, stable, and linear. A simple model with this parameterization and no additional nonlinearities reproduces a realistic ENSO cycle with intermittent El Niño and La Niña events of varying intensity and strength as well as realistic buildup and shutdown of wind burst activity in the western Pacific. The wind burst activity has a direct causal effect on the ENSO variability: in particular, it intermittently triggers regular El Niño or La Niña events, super El Niño events, or no events at all, which enables the model to capture observed ENSO statistics such as the probability density function and power spectrum of eastern Pacific sea surface temperatures. The present framework provides further theoretical and practical insight on the relationship between wind burst activity and the ENSO. PMID:27573821

Relationship between Mind and Brain: A Proposal of Solution Based on Forms of Intra- and Extra-Individual Negentropy

ERIC Educational Resources Information Center

Alegre, Alberto A.; Zumaeta, Pablo A.

2015-01-01

It is proposed that the problem of the mind-brain relationship can be overcome by a non-classical materialistic model of personality based on the information defined as a special form of negentropy with a structure and activity, which in five intra-individual categories, organizes all and each of the levels of the personality, and, in an…

Impact of childhood maltreatment on physical health-related quality of life in U.S. active duty military personnel and combat veterans.

PubMed

Aversa, Laura H; Lemmer, Jennifer; Nunnink, Sarah; McLay, Robert N; Baker, Dewleen G

2014-08-01

Previous studies have found an association between childhood maltreatment (CM) and health-related quality of life (HRQoL), and to a lesser extent have considered whether psychiatric symptoms may explain the relationship. This study aimed to further our understanding of the link between CM and HRQoL by testing whether posttraumatic stress disorder (PTSD) or depressive symptoms mediate the relationship between childhood maltreatment and physical HRQoL. Mediation models were examined in a sample of male Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) active duty and combat veterans (n=249). PTSD and depressive symptoms mediated the relationship between CM and overall physical HRQoL, as well as participation in daily activities due to physical health, bodily pain, and social functioning. Mediation of the relationship between childhood maltreatment and physical and social functioning by depression and PTSD symptoms may lend support to neurobiological hypotheses that childhood maltreatment sensitizes the nervous system and after repeated trauma may lead to the development of psychiatric symptoms, which have a major impact on morbidity and mortality. Published by Elsevier Ltd.

Neural electrical activity and neural network growth.

PubMed

Gafarov, F M

2018-05-01

The development of central and peripheral neural system depends in part on the emergence of the correct functional connectivity in its input and output pathways. Now it is generally accepted that molecular factors guide neurons to establish a primary scaffold that undergoes activity-dependent refinement for building a fully functional circuit. However, a number of experimental results obtained recently shows that the neuronal electrical activity plays an important role in the establishing of initial interneuronal connections. Nevertheless, these processes are rather difficult to study experimentally, due to the absence of theoretical description and quantitative parameters for estimation of the neuronal activity influence on growth in neural networks. In this work we propose a general framework for a theoretical description of the activity-dependent neural network growth. The theoretical description incorporates a closed-loop growth model in which the neural activity can affect neurite outgrowth, which in turn can affect neural activity. We carried out the detailed quantitative analysis of spatiotemporal activity patterns and studied the relationship between individual cells and the network as a whole to explore the relationship between developing connectivity and activity patterns. The model, developed in this work will allow us to develop new experimental techniques for studying and quantifying the influence of the neuronal activity on growth processes in neural networks and may lead to a novel techniques for constructing large-scale neural networks by self-organization. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Lifespan Perspective on Entrepreneurship: Perceived Opportunities and Skills Explain the Negative Association between Age and Entrepreneurial Activity.

PubMed

Bohlmann, Clarissa; Rauch, Andreas; Zacher, Hannes

2017-01-01

Researchers and practitioners are increasingly interested in entrepreneurship as a means to fight youth unemployment and to improve financial stability at higher ages. However, only few studies so far have examined the association between age and entrepreneurial activity. Based on theories from the lifespan psychology literature and entrepreneurship, we develop and test a model in which perceived opportunities and skills explain the relationship between age and entrepreneurial activity. We analyzed data from the 2013 Global Entrepreneurship Monitor (GEM), while controlling for gender and potential variation between countries. Results showed that age related negatively to entrepreneurial activity, and that perceived opportunities and skills for entrepreneurship mediated this relationship. Overall, these findings suggest that entrepreneurship research should treat age as a substantial variable.

A Lifespan Perspective on Entrepreneurship: Perceived Opportunities and Skills Explain the Negative Association between Age and Entrepreneurial Activity

PubMed Central

Bohlmann, Clarissa; Rauch, Andreas; Zacher, Hannes

2017-01-01

Researchers and practitioners are increasingly interested in entrepreneurship as a means to fight youth unemployment and to improve financial stability at higher ages. However, only few studies so far have examined the association between age and entrepreneurial activity. Based on theories from the lifespan psychology literature and entrepreneurship, we develop and test a model in which perceived opportunities and skills explain the relationship between age and entrepreneurial activity. We analyzed data from the 2013 Global Entrepreneurship Monitor (GEM), while controlling for gender and potential variation between countries. Results showed that age related negatively to entrepreneurial activity, and that perceived opportunities and skills for entrepreneurship mediated this relationship. Overall, these findings suggest that entrepreneurship research should treat age as a substantial variable. PMID:29250004

The Relationship between Big Data and Mathematical Modeling: A Discussion in a Mathematical Education Scenario

ERIC Educational Resources Information Center

Dalla Vecchia, Rodrigo

2015-01-01

This study discusses aspects of the association between Mathematical Modeling (MM) and Big Data in the scope of mathematical education. We present an example of an activity to discuss two ontological factors that involve MM. The first is linked to the modeling stages. The second involves the idea of pedagogical objectives. The main findings…

The Relationship between Shared Mental Models and Task Performance in an Online Team- Based Learning Environment

ERIC Educational Resources Information Center

Johnson, Tristan E.; Lee, Youngmin

2008-01-01

In an effort to better understand learning teams, this study examines the effects of shared mental models on team and individual performance. The results indicate that each team's shared mental model changed significantly over the time that subjects participated in team-based learning activities. The results also showed that the shared mental…

Switch On Student Interest.

ERIC Educational Resources Information Center

Nelson, Jane B.

2000-01-01

Describes a set of laboratory activities in which students construct a model for the relationship between potential difference (measured in volts) and current (measured in amperes) in a DC circuit with a single resistor. (SAH)

Towards a physics-based multiscale modelling of the electro-mechanical coupling in electro-active polymers.

PubMed

Cohen, Noy; Menzel, Andreas; deBotton, Gal

2016-02-01

Owing to the increasing number of industrial applications of electro-active polymers (EAPs), there is a growing need for electromechanical models which accurately capture their behaviour. To this end, we compare the predicted behaviour of EAPs undergoing homogeneous deformations according to three electromechanical models. The first model is a phenomenological continuum-based model composed of the mechanical Gent model and a linear relationship between the electric field and the polarization. The electrical and the mechanical responses according to the second model are based on the physical structure of the polymer chain network. The third model incorporates a neo-Hookean mechanical response and a physically motivated microstructurally based long-chains model for the electrical behaviour. In the microstructural-motivated models, the integration from the microscopic to the macroscopic levels is accomplished by the micro-sphere technique. Four types of homogeneous boundary conditions are considered and the behaviours determined according to the three models are compared. For the microstructurally motivated models, these analyses are performed and compared with the widely used phenomenological model for the first time. Some of the aspects revealed in this investigation, such as the dependence of the intensity of the polarization field on the deformation, highlight the need for an in-depth investigation of the relationships between the structure and the behaviours of the EAPs at the microscopic level and their overall macroscopic response.

Simplified molecular input line entry system-based: QSAR modelling for MAP kinase-interacting protein kinase (MNK1).

PubMed

Begum, S; Achary, P Ganga Raju

2015-01-01

Quantitative structure-activity relationship (QSAR) models were built for the prediction of inhibition (pIC50, i.e. negative logarithm of the 50% effective concentration) of MAP kinase-interacting protein kinase (MNK1) by 43 potent inhibitors. The pIC50 values were modelled with five random splits, with the representations of the molecular structures by simplified molecular input line entry system (SMILES). QSAR model building was performed by the Monte Carlo optimisation using three methods: classic scheme; balance of correlations; and balance correlation with ideal slopes. The robustness of these models were checked by parameters as rm(2), r(*)m(2), [Formula: see text] and randomisation technique. The best QSAR model based on single optimal descriptors was applied to study in vitro structure-activity relationships of 6-(4-(2-(piperidin-1-yl) ethoxy) phenyl)-3-(pyridin-4-yl) pyrazolo [1,5-a] pyrimidine derivatives as a screening tool for the development of novel potent MNK1 inhibitors. The effects of alkyl group, -OH, -NO2, F, Cl, Br, I, etc. on the IC50 values towards the inhibition of MNK1 were also reported.

The Influence of Race-Ethnicity and Physical Activity Levels on Elementary School Achievement

ERIC Educational Resources Information Center

Caldas, Stephen J.; Reilly, Monique S.

2018-01-01

The authors used structural equation modeling to map the relationships between student race-ethnicity via the mediating variable physical activity on English language arts (ELA) and mathematics achievement among 964 fourth- and fifth-grade students. The students attended a New York City Metropolitan area school district and completed the Physical…

Hyperactivity in Boys with Attention-Deficit/Hyperactivity Disorder (ADHD): A Ubiquitous Core Symptom or Manifestation of Working Memory Deficits?

ERIC Educational Resources Information Center

Rapport, Mark D.; Bolden, Jennifer; Kofler, Michael J.; Sarver, Dustin E.; Raiker, Joseph S.; Alderson, R. Matt

2009-01-01

Hyperactivity is currently considered a core and ubiquitous feature of attention-deficit/hyperactivity disorder (ADHD); however, an alternative model challenges this premise and hypothesizes a functional relationship between working memory (WM) and activity level. The current study investigated whether children's activity level is functionally…

Do Specific Classroom Reading Activities Predict English Language Learners' Later Reading Achievement?

ERIC Educational Resources Information Center

Swanson, H. Lee; Orosco, Michael J.; Kudo, Milagros Fatima

2017-01-01

This study investigated the relationship between elementary classroom (N = 50) reading activities in Year 1 and reading performance (i.e., passage comprehension, letter-word identification, and word attack) 1 year later for English language learners (ELLs; N = 270). A cross-classification hierarchical model indicated that compared to other reading…

Influence of lipophilicity in O-acyl and O-alkyl derivatives of juglone and lawsone: a structure-activity relationship study in the search for natural herbicide models.

PubMed

Durán, Alexandra G; Chinchilla, Nuria; Molinillo, José Mg; Macías, Francisco A

2018-03-01

Naphthoquinones are known for their broad range of biological activities. Given the increasing demands of consumers in relation to food quality and growing concerns about the impact of synthetic herbicides, it is necessary to search for new agrochemicals. Natural products and allelopathy provide new alternatives for the development of pesticides with lower toxicity and greater environmental compatibility. A structure-activity relationship to evaluate the effect of bioavailability was performed. A total of 44 O-acyl and O-alkyl derivatives of juglone and lawsone with different linear chain lengths were prepared. These compounds were tested on etiolated wheat coleoptiles, standard target species (STS) and four weeds, Echinochloa crus-galli L., Lolium rigidum Gaud., Lolium perenne L. and Avena fatua L. The results showed a strong influence of lipophilicity and, in most cases, the data fitted a logP-dependent quadratic mathematical model. The effects produced were mostly stunting and necrosis caused by growth inhibition. The potential structure and activity behaviour is described. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Fathers’ Participation in Parenting and Maternal Parenting Stress: Variation by Relationship Status

PubMed Central

Nomaguchi, Kei; Brown, Susan L.; Leyman, Tanya M.

2015-01-01

The growing diversity in mother-father relationship status has led to a debate over the role of fathers in parenting. Little is known, however, about how fathers’ participation in parenting is linked to maternal well-being across different mother-father relationship statuses. Using data from the Fragile Families and Child Wellbeing Study (N = 2,062), fixed-effects as well as random-effects regression models show that overall fathers’ engagement with children and sharing in child-related chores are negatively related to maternal parenting stress. Fathers’ cooperative coparenting is negatively related to maternal parenting stress only in the random-effects model, suggesting that the association is driven by selection factors. There is little variation in these associations by mother-father relationship status, once selection factors are controlled for. These findings extend support for the current cultural emphasis on benefits of fathers’ active participation in parenting for mothers and children even after the mother-father relationship dissolved. PMID:28479649

New Look at Social Support: A Theoretical Perspective on Thriving through Relationships

PubMed Central

Feeney, Brooke C.; Collins, Nancy L.

2017-01-01

Close and caring relationships are undeniably linked to health and well-being at all stages in the lifespan. Yet the specific pathways through which close relationships promote optimal well-being are not well understood. In this article, we present a model of thriving through relationships to provide a theoretical foundation for identifying the specific interpersonal processes that underlie the effects of close relationships on thriving. This model highlights two life contexts through which people may potentially thrive (coping successfully with life’s adversities and actively pursuing life opportunities for growth and development), it proposes two relational support functions that are fundamental to the experience of thriving in each life context, and it identifies mediators through which relational support is likely to have long-term effects on thriving. This perspective highlights the need for researchers to take a new look at social support by conceptualizing it as an interpersonal process with a focus on thriving. PMID:25125368

Automatic prediction of solar flares and super geomagnetic storms

NASA Astrophysics Data System (ADS)

Song, Hui

Space weather is the response of our space environment to the constantly changing Sun. As the new technology advances, mankind has become more and more dependent on space system, satellite-based services. A geomagnetic storm, a disturbance in Earth's magnetosphere, may produce many harmful effects on Earth. Solar flares and Coronal Mass Ejections (CMEs) are believed to be the major causes of geomagnetic storms. Thus, establishing a real time forecasting method for them is very important in space weather study. The topics covered in this dissertation are: the relationship between magnetic gradient and magnetic shear of solar active regions; the relationship between solar flare index and magnetic features of solar active regions; based on these relationships a statistical ordinal logistic regression model is developed to predict the probability of solar flare occurrences in the next 24 hours; and finally the relationship between magnetic structures of CME source regions and geomagnetic storms, in particular, the super storms when the D st index decreases below -200 nT is studied and proved to be able to predict those super storms. The results are briefly summarized as follows: (1) There is a significant correlation between magnetic gradient and magnetic shear of active region. Furthermore, compared with magnetic shear, magnetic gradient might be a better proxy to locate where a large flare occurs. It appears to be more accurate in identification of sources of X-class flares than M-class flares; (2) Flare index, defined by weighting the SXR flares, is proved to have positive correlation with three magnetic features of active region; (3) A statistical ordinal logistic regression model is proposed for solar flare prediction. The results are much better than those data published in the NASA/SDAC service, and comparable to the data provided by the NOAA/SEC complicated expert system. To our knowledge, this is the first time that logistic regression model has been applied in solar physics to predict flare occurrences; (4) The magnetic orientation angle [straight theta], determined from a potential field model, is proved to be able to predict the probability of super geomagnetic storms (D= st <=-200nT). The results show that those active regions associated with | [straight theta]| < 90° are more likely to cause a super geomagnetic storm.

Childhood EEG frontal alpha power as a predictor of adolescent antisocial behavior: A twin heritability study

PubMed Central

Niv, Sharon; Ashrafulla, Syed; Tuvblad, Catherine; Joshi, Anand; Raine, Adrian; Leahy, Richard; Baker, Laura A.

2015-01-01

High EEG frontal alpha power (FAP) is thought to represent a state of low arousal in the brain, which has been related in past research to antisocial behavior (ASB). We investigated a longitudinal sample of 900 twins in two assessments in late childhood and mid-adolescence to verify whether relationships exist between FAP and both aggressive and nonaggressive ASB. ASB was measured by the Child Behavioral Checklist, and FAP was calculated using connectivity analysis methods that used principal components analysis to derive power of the most dominant frontal activation. Significant positive predictive relationships emerged in males between childhood FAP and adolescent aggressive ASB using multilevel mixed modeling. No concurrent relationships were found. Using bivariate biometric twin modeling analysis, the relationship between childhood FAP and adolescent aggressive ASB in males was found to be entirely due to genetic factors, which were correlated r = 0.22. PMID:25456277

Motivation Mediates the Perfectionism-Burnout Relationship: A Three-Wave Longitudinal Study With Junior Athletes.

PubMed

Madigan, Daniel J; Stoeber, Joachim; Passfield, Louis

2016-08-01

Perfectionism in sports has been shown to predict longitudinal changes in athlete burnout. What mediates these changes over time, however, is still unclear. Adopting a self-determination theory perspective and using a three-wave longitudinal design, the current study examined perfectionistic strivings, perfectionistic concerns, autonomous motivation, controlled motivation, and athlete burnout in 141 junior athletes (mean age = 17.3 years) over 6 months of active training. When multilevel structural equation modeling was employed to test a mediational model, a differential pattern of between- and within-person relationships emerged. Whereas autonomous motivation mediated the negative relationship that perfectionistic strivings had with burnout at the between- and within-person level, controlled motivation mediated the positive relationship that perfectionistic concerns had with burnout at the between-persons level only. The present findings suggest that differences in autonomous and controlled motivation explain why perfectionism predicts changes in athlete burnout over time.

Computational studies of novel chymase inhibitors against cardiovascular and allergic diseases: mechanism and inhibition.

PubMed

Arooj, Mahreen; Thangapandian, Sundarapandian; John, Shalini; Hwang, Swan; Park, Jong K; Lee, Keun W

2012-12-01

To provide a new idea for drug design, a computational investigation is performed on chymase and its novel 1,4-diazepane-2,5-diones inhibitors that explores the crucial molecular features contributing to binding specificity. Molecular docking studies of inhibitors within the active site of chymase were carried out to rationalize the inhibitory properties of these compounds and understand their inhibition mechanism. The density functional theory method was used to optimize molecular structures with the subsequent analysis of highest occupied molecular orbital, lowest unoccupied molecular orbital, and molecular electrostatic potential maps, which revealed that negative potentials near 1,4-diazepane-2,5-diones ring are essential for effective binding of inhibitors at active site of enzyme. The Bayesian model with receiver operating curve statistic of 0.82 also identified arylsulfonyl and aminocarbonyl as the molecular features favoring and not favoring inhibition of chymase, respectively. Moreover, genetic function approximation was applied to construct 3D quantitative structure-activity relationships models. Two models (genetic function approximation model 1 r(2) = 0.812 and genetic function approximation model 2 r(2) = 0.783) performed better in terms of correlation coefficients and cross-validation analysis. In general, this study is used as example to illustrate how combinational use of 2D/3D quantitative structure-activity relationships modeling techniques, molecular docking, frontier molecular orbital density fields (highest occupied molecular orbital and lowest unoccupied molecular orbital), and molecular electrostatic potential analysis may be useful to gain an insight into the binding mechanism between enzyme and its inhibitors. © 2012 John Wiley & Sons A/S.

Models of physician-patient relationships in pharmaceutical direct-to-consumer advertising and consumer interviews.

PubMed

Arney, Jennifer; Lewin, Benjamin

2013-07-01

The rise of direct-to-consumer advertising (DTCA) has mirrored, if not facilitated, the shift toward more active health care consumers. We used content analysis to identify models of physician-patient interaction in DTCA from the 1997 to 2006 issues of a broad sample of women's, men's, and common readership magazines. We also conducted 36 in-depth interviews to examine the ways consumers receive and regard advertising messages, and to explore their preferences for clinical communication and decision making. We identified four models of physician-patient relationships that vary in their locus of control (physician, patient, or shared) and the form of support sought or obtained in the relationship (emotional or instrumental). Whereas consumer interviews reflected references to all four models of interaction, only two appeared in DTCA. The limited range of interactions seen in these advertisements creates a lack of congruity between interaction styles found in advertisements vs. styles reported by actual consumers.

Attachment, childhood abuse, and IBD-related quality of life and disease activity outcomes.

PubMed

Caplan, Rachel A; Maunder, Robert G; Stempak, Joanne M; Silverberg, Mark S; Hart, Tae L

2014-05-01

This study examined attachment style as a moderator of the relationship between childhood abuse and inflammatory bowel disease (IBD)-related outcomes. Study participants were 205 patients with IBD from Mount Sinai Hospital in Toronto. Participants completed self-report questionnaires regarding personal relationships, abuse history, and IBD-related information. Multiple regression models were fit using 3 outcome variables: disease-related quality of life (QOL), disease activity for ulcerative colitis, and disease activity for Crohn's disease. Patients reporting less severe abuse and low levels of avoidant attachment had the highest levels of QOL, whereas patients reporting high levels of avoidant attachment had the lowest levels of QOL, regardless of abuse severity. Patients reporting greater anxious attachment had lower QOL scores. Patients reporting less severe abuse and low levels of avoidant attachment had the lowest levels of disease activity, whereas patients reporting high levels of avoidant attachment had the highest levels of ulcerative colitis-related disease activity, regardless of abuse severity. However, for anxious attachment, there was no significant main effect or significant interaction of abuse by anxious attachment on ulcerative colitis-related disease activity. Childhood abuse and attachment style were not found to be associated with Crohn's disease-related disease activity. Adult attachment style may moderate the relationship between childhood abuse and IBD-related outcomes, by impacting one's QOL and disease activity. Distinct types of insecure attachment styles may impact these relationships differently. Psychological interventions focusing on attachment styles of patients with IBD have the potential to improve IBD-related QOL and disease activity.

Time with friends and physical activity as mechanisms linking obesity and television viewing among youth

PubMed Central

2015-01-01

Background Though bivariate relationships between childhood obesity, physical activity, friendships and television viewing are well documented, empirical assessment of the extent to which links between obesity and television may be mediated by these factors is scarce. This study examines the possibility that time with friends and physical activity are potential mechanisms linking overweight/obesity to television viewing in youth. Methods Data were drawn from children ages 10-18 years old (M = 13.81, SD = 2.55) participating in the 2002 wave of Child Development Supplement (CDS) to the Panel Study of Income Dynamics (PSID) (n = 1,545). Data were collected both directly and via self-report from children and their parents. Path analysis was employed to examine a model whereby the relationships between youth overweight/obesity and television viewing were mediated by time spent with friends and moderate-to-vigorous physical activity (MVPA). Results Overweight/obesity was directly related to less time spent with friends, but not to MVPA. Time spent with friends was directly and positively related to MVPA, and directly and negatively related to time spent watching television without friends. In turn, MVPA was directly and negatively related to watching television without friends. There were significant indirect effects of both overweight/obesity and time with friends on television viewing through MVPA, and of overweight/obesity on MVPA through time with friends. Net of any indirect effects, the direct effect of overweight/obesity on television viewing remained. The final model fit the data extremely well (χ2 = 5.77, df = 5, p<0.0001, RMSEA = 0.01, CFI = 0.99, TLI =0.99). Conclusions We found good evidence that the positive relationships between time with friends and physical activity are important mediators of links between overweight/obesity and television viewing in youth. These findings highlight the importance of moving from examinations of bivariate relationships between weight status and television viewing to more nuanced explanatory models which attempt to identify and unpack the possible mechanisms linking them. PMID:26221737

Insight into the Structural Determinants of Imidazole Scaffold-Based Derivatives as TNF-α Release Inhibitors by in Silico Explorations

PubMed Central

Wang, Yuan; Wu, Mingwei; Ai, Chunzhi; Wang, Yonghua

2015-01-01

Presently, 151 widely-diverse pyridinylimidazole-based compounds that show inhibitory activities at the TNF-α release were investigated. By using the distance comparison technique (DISCOtech), comparative molecular field analysis (CoMFA), and comparative molecular similarity index analysis (CoMSIA) methods, the pharmacophore models and the three-dimensional quantitative structure-activity relationships (3D-QSAR) of the compounds were explored. The proposed pharmacophore model, including two hydrophobic sites, two aromatic centers, two H-bond donor atoms, two H-bond acceptor atoms, and two H-bond donor sites characterizes the necessary structural features of TNF-α release inhibitors. Both the resultant CoMFA and CoMSIA models exhibited satisfactory predictability (with Q2 (cross-validated correlation coefficient) = 0.557, R2ncv (non-cross-validated correlation coefficient) = 0.740, R2pre (predicted correlation coefficient) = 0.749 and Q2 = 0.598, R2ncv = 0.767, R2pre = 0.860, respectively). Good consistency was observed between the 3D-QSAR models and the pharmacophore model that the hydrophobic interaction and hydrogen bonds play crucial roles in the mechanism of actions. The corresponding contour maps generated by these models provide more diverse information about the key intermolecular interactions of inhibitors with the surrounding environment. All these models have extended the understanding of imidazole-based compounds in the structure-activity relationship, and are useful for rational design and screening of novel 2-thioimidazole-based TNF-α release inhibitors. PMID:26307982

Insight into the Structural Determinants of Imidazole Scaffold-Based Derivatives as TNF-α Release Inhibitors by in Silico Explorations.

PubMed

Wang, Yuan; Wu, Mingwei; Ai, Chunzhi; Wang, Yonghua

2015-08-25

Presently, 151 widely-diverse pyridinylimidazole-based compounds that show inhibitory activities at the TNF-α release were investigated. By using the distance comparison technique (DISCOtech), comparative molecular field analysis (CoMFA), and comparative molecular similarity index analysis (CoMSIA) methods, the pharmacophore models and the three-dimensional quantitative structure-activity relationships (3D-QSAR) of the compounds were explored. The proposed pharmacophore model, including two hydrophobic sites, two aromatic centers, two H-bond donor atoms, two H-bond acceptor atoms, and two H-bond donor sites characterizes the necessary structural features of TNF-α release inhibitors. Both the resultant CoMFA and CoMSIA models exhibited satisfactory predictability (with Q(2) (cross-validated correlation coefficient) = 0.557, R(2)ncv (non-cross-validated correlation coefficient) = 0.740, R(2)pre (predicted correlation coefficient) = 0.749 and Q(2) = 0.598, R(2)ncv = 0.767, R(2)pre = 0.860, respectively). Good consistency was observed between the 3D-QSAR models and the pharmacophore model that the hydrophobic interaction and hydrogen bonds play crucial roles in the mechanism of actions. The corresponding contour maps generated by these models provide more diverse information about the key intermolecular interactions of inhibitors with the surrounding environment. All these models have extended the understanding of imidazole-based compounds in the structure-activity relationship, and are useful for rational design and screening of novel 2-thioimidazole-based TNF-α release inhibitors.

STRUCTURE-ACTIVITY RELATIONSHIPS--COMPUTERIZED SYSTEMS

EPA Science Inventory

This report discusses some important general strategies and issuesrelative to the application of computational SAR techniques formodeling genotoxicity and carcinogenicity endpoints. roblemsparticular to the SAR modeling of such endpoints pertain to: hecomplexity of the carcinogen...

Phenotypic variation in metabolism and morphology correlating with animal swimming activity in the wild: relevance for the OCLTT (oxygen- and capacity-limitation of thermal tolerance), allocation and performance models

PubMed Central

Baktoft, Henrik; Jacobsen, Lene; Skov, Christian; Koed, Anders; Jepsen, Niels; Berg, Søren; Boel, Mikkel; Aarestrup, Kim; Svendsen, Jon C.

2016-01-01

Ongoing climate change is affecting animal physiology in many parts of the world. Using metabolism, the oxygen- and capacity-limitation of thermal tolerance (OCLTT) hypothesis provides a tool to predict the responses of ectothermic animals to variation in temperature, oxygen availability and pH in the aquatic environment. The hypothesis remains controversial, however, and has been questioned in several studies. A positive relationship between aerobic metabolic scope and animal activity would be consistent with the OCLTT but has rarely been tested. Moreover, the performance model and the allocation model predict positive and negative relationships, respectively, between standard metabolic rate and activity. Finally, animal activity could be affected by individual morphology because of covariation with cost of transport. Therefore, we hypothesized that individual variation in activity is correlated with variation in metabolism and morphology. To test this prediction, we captured 23 wild European perch (Perca fluviatilis) in a lake, tagged them with telemetry transmitters, measured standard and maximal metabolic rates, aerobic metabolic scope and fineness ratio and returned the fish to the lake to quantify individual in situ activity levels. Metabolic rates were measured using intermittent flow respirometry, whereas the activity assay involved high-resolution telemetry providing positions every 30 s over 12 days. We found no correlation between individual metabolic traits and activity, whereas individual fineness ratio correlated with activity. Independent of body length, and consistent with physics theory, slender fish maintained faster mean and maximal swimming speeds, but this variation did not result in a larger area (in square metres) explored per 24 h. Testing assumptions and predictions of recent conceptual models, our study indicates that individual metabolism is not a strong determinant of animal activity, in contrast to individual morphology, which is correlated with in situ activity patterns. PMID:27382465

A DOUBLE-RING ALGORITHM FOR MODELING SOLAR ACTIVE REGIONS: UNIFYING KINEMATIC DYNAMO MODELS AND SURFACE FLUX-TRANSPORT SIMULATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Munoz-Jaramillo, Andres; Martens, Petrus C. H.; Nandy, Dibyendu

The emergence of tilted bipolar active regions (ARs) and the dispersal of their flux, mediated via processes such as diffusion, differential rotation, and meridional circulation, is believed to be responsible for the reversal of the Sun's polar field. This process (commonly known as the Babcock-Leighton mechanism) is usually modeled as a near-surface, spatially distributed {alpha}-effect in kinematic mean-field dynamo models. However, this formulation leads to a relationship between polar field strength and meridional flow speed which is opposite to that suggested by physical insight and predicted by surface flux-transport simulations. With this in mind, we present an improved double-ring algorithmmore » for modeling the Babcock-Leighton mechanism based on AR eruption, within the framework of an axisymmetric dynamo model. Using surface flux-transport simulations, we first show that an axisymmetric formulation-which is usually invoked in kinematic dynamo models-can reasonably approximate the surface flux dynamics. Finally, we demonstrate that our treatment of the Babcock-Leighton mechanism through double-ring eruption leads to an inverse relationship between polar field strength and meridional flow speed as expected, reconciling the discrepancy between surface flux-transport simulations and kinematic dynamo models.« less

A Quantitative Structure Activity Relationship for acute oral toxicity of pesticides on rats: Validation, domain of application and prediction.

PubMed

Hamadache, Mabrouk; Benkortbi, Othmane; Hanini, Salah; Amrane, Abdeltif; Khaouane, Latifa; Si Moussa, Cherif

2016-02-13

Quantitative Structure Activity Relationship (QSAR) models are expected to play an important role in the risk assessment of chemicals on humans and the environment. In this study, we developed a validated QSAR model to predict acute oral toxicity of 329 pesticides to rats because a few QSAR models have been devoted to predict the Lethal Dose 50 (LD50) of pesticides on rats. This QSAR model is based on 17 molecular descriptors, and is robust, externally predictive and characterized by a good applicability domain. The best results were obtained with a 17/9/1 Artificial Neural Network model trained with the Quasi Newton back propagation (BFGS) algorithm. The prediction accuracy for the external validation set was estimated by the Q(2)ext and the root mean square error (RMS) which are equal to 0.948 and 0.201, respectively. 98.6% of external validation set is correctly predicted and the present model proved to be superior to models previously published. Accordingly, the model developed in this study provides excellent predictions and can be used to predict the acute oral toxicity of pesticides, particularly for those that have not been tested as well as new pesticides. Copyright © 2015 Elsevier B.V. All rights reserved.

Predicting human skin absorption of chemicals: development of a novel quantitative structure activity relationship.

PubMed

Luo, Wen; Medrek, Sarah; Misra, Jatin; Nohynek, Gerhard J

2007-02-01

The objective of this study was to construct and validate a quantitative structure-activity relationship model for skin absorption. Such models are valuable tools for screening and prioritization in safety and efficacy evaluation, and risk assessment of drugs and chemicals. A database of 340 chemicals with percutaneous absorption was assembled. Two models were derived from the training set consisting 306 chemicals (90/10 random split). In addition to the experimental K(ow) values, over 300 2D and 3D atomic and molecular descriptors were analyzed using MDL's QsarIS computer program. Subsequently, the models were validated using both internal (leave-one-out) and external validation (test set) procedures. Using the stepwise regression analysis, three molecular descriptors were determined to have significant statistical correlation with K(p) (R2 = 0.8225): logK(ow), X0 (quantification of both molecular size and the degree of skeletal branching), and SsssCH (count of aromatic carbon groups). In conclusion, two models to estimate skin absorption were developed. When compared to other skin absorption QSAR models in the literature, our model incorporated more chemicals and explored a large number of descriptors. Additionally, our models are reasonably predictive and have met both internal and external statistical validations.

Linking water quality and quantity in environmental flow assessment in deteriorated ecosystems: a food web view.

PubMed

Chen, He; Ma, Lekuan; Guo, Wei; Yang, Ying; Guo, Tong; Feng, Cheng

2013-01-01

Most rivers worldwide are highly regulated by anthropogenic activities through flow regulation and water pollution. Environmental flow regulation is used to reduce the effects of anthropogenic activities on aquatic ecosystems. Formulating flow alteration-ecological response relationships is a key factor in environmental flow assessment. Traditional environmental flow models are characterized by natural relationships between flow regimes and ecosystem factors. However, food webs are often altered from natural states, which disturb environmental flow assessment in such ecosystems. In ecosystems deteriorated by heavy anthropogenic activities, the effects of environmental flow regulation on species are difficult to assess with current modeling approaches. Environmental flow management compels the development of tools that link flow regimes and food webs in an ecosystem. Food web approaches are more suitable for the task because they are more adaptive for disordered multiple species in a food web deteriorated by anthropogenic activities. This paper presents a global method of environmental flow assessment in deteriorated aquatic ecosystems. Linkages between flow regimes and food web dynamics are modeled by incorporating multiple species into an ecosystem to explore ecosystem-based environmental flow management. The approach allows scientists and water resources managers to analyze environmental flows in deteriorated ecosystems in an ecosystem-based way.

Built Environment Influences of Children's Physical Activity: Examining Differences by Neighbourhood Size and Sex.

PubMed

Mitchell, Christine A; Clark, Andrew F; Gilliland, Jason A

2016-01-15

Neighbourhoods can facilitate or constrain moderate-to-vigorous physical activity (MVPA) among children by providing or restricting opportunities for MVPA. However, there is no consensus on how to define a child's neighbourhood. This study examines the influence of the neighbourhood built environment on objectively measured MVPA among 435 children (aged 9-14 years) in London (ON, Canada). As there is no consensus on how to delineate a child's neighbourhood, a geographic information system was used to generate measures of the neighbourhood built environment at two buffer sizes (500 m and 800 m) around each child's home. Linear regression models with robust standard errors (cluster) were used to analyze the relationship between built environment characteristics and average daily MVPA during non-school hours on weekdays. Sex-stratified models assessed sex-specific relationships. When accounting for individual and neighbourhood socio-demographic variables, park space and multi-use path space were found to influence children's MVPA. Sex-stratified models found significant associations between MVPA and park space, with the 800 m buffer best explaining boys' MVPA and the 500 m buffer best explaining girls' MVPA. Findings emphasize that, when designing built environments, programs, and policies to facilitate physical activity, it is important to consider that the size of the neighbourhood influencing a child's physical activity may differ according to sex.

Quantitative structure--property relationships for enhancing predictions of synthetic organic chemical removal from drinking water by granular activated carbon.

PubMed

Magnuson, Matthew L; Speth, Thomas F

2005-10-01

Granular activated carbon is a frequently explored technology for removing synthetic organic contaminants from drinking water sources. The success of this technology relies on a number of factors based not only on the adsorptive properties of the contaminant but also on properties of the water itself, notably the presence of substances in the water which compete for adsorption sites. Because it is impractical to perform field-scale evaluations for all possible contaminants, the pore surface diffusion model (PSDM) has been developed and used to predict activated carbon column performance using single-solute isotherm data as inputs. Many assumptions are built into this model to account for kinetics of adsorption and competition for adsorption sites. This work further evaluates and expands this model, through the use of quantitative structure-property relationships (QSPRs) to predict the effect of natural organic matter fouling on activated carbon adsorption of specific contaminants. The QSPRs developed are based on a combination of calculated topographical indices and quantum chemical parameters. The QSPRs were evaluated in terms of their statistical predictive ability,the physical significance of the descriptors, and by comparison with field data. The QSPR-enhanced PSDM was judged to give results better than what could previously be obtained.

Outdoor time, physical activity, sedentary time, and health indicators at ages 7 to 14: 2012/2013 Canadian Health Measures Survey.

PubMed

Larouche, Richard; Garriguet, Didier; Gunnell, Katie E; Goldfield, Gary S; Tremblay, Mark S

2016-09-21

International data show that the majority of children and youth are not sufficiently active. According to recent research, children who spend more time outdoors accumulate more daily moderate-to-vigorous physical activity and engage in less sedentary behaviour. However, the generalizability of these findings is uncertain, and few studies investigated whether outdoor time is associated with other physical and psychosocial health indicators. This study examined associations between outdoor time and measures of physical activity, sedentary time, and physical and psychosocial health in a nationally representative sample of 7-to-14-year-olds (n = 1,159) who participated in the 2012/2013 Canadian Health Measures Survey. Physical activity and sedentary time were measured with Actical accelerometers. Direct measures of height, weight, waist circumference, grip strength, blood pressure, cholesterol, and glycohemoglobin were obtained. The Strengths and Difficulties Questionnaire was used to assess psychosocial health. Relationships between outdoor time and physical health measures were examined with multi-variable linear regression models adjusted for age, sex, parental education, and household income. Logistic regression models controlling for the same variables were used for psychosocial health. Each additional hour spent outdoors per day was associated with 7.0 more minutes of moderate-to-vigorous physical activity, 762 more steps, and 13 fewer minutes of sedentary time. As well, each hour outdoors was associated with lower odds of negative psychosocial outcomes (specifically, peer relationship problems and total difficulties score). Outdoor time was not associated with any of the measures of physical health. Children reporting more time outdoors are more active, less sedentary, and less likely to have peer relationship problems, compared with those who spend less time outdoors.

Quantitative structure property relationships for the adsorption of pharmaceuticals onto activated carbon.

PubMed

Dickenson, E R V; Drewes, J E

2010-01-01

Isotherms were determined for the adsorption of five pharmaceutical residues, primidone, carbamazepine, ibuprofen, naproxen and diclofenac, to Calgon Filtrasorb 300 powdered activated carbon (PAC). The sorption behavior was examined in ultra-pure and wastewater effluent organic matter (EfOM) matrices, where more sorption was observed in the ultra-pure water for PAC doses greater than 10 mg/L suggesting the presence of EfOM hinders the sorption of the pharmaceuticals to the PAC. Adsorption behaviors were described by the Freundlich isotherm model. Quantitative structure property relationships (QSPRs) in the form of polyparameter linear solvation energy relationships were developed for simulating the Freundlich adsorption capacity in both ultra-pure and EfOM matrices. The significant 3D-based descriptors for the QSPRs were the molar volume, polarizability and hydrogen-bond donor parameters.

In vitro-in vivo activity relationship of substituted benzimidazole cell division inhibitors with activity against Mycobacteria tuberculosis

PubMed Central

Knudson, Susan E.; Kumar, Kunal; Awasthi, Divya; Ojima, Iwao; Slayden, Richard A.

2014-01-01

Structure based drug design was used to develop a compound library of novel 2,5,6- and 2,5,7-trisubstituted benzimidazoles. Three structural analogs, SB-P1G10, SB-P8B2 and SB-P3G2 were selected from this library based on previous studies for advanced study. In vitro studies revealed that SB-P8B2 and SB-P3G2 had sigmoidal kill-curves while in contrast SB-P1G10 showed a narrow zonal susceptibility. The in vitro studies also demonstrated that exposure to SB-P8B2 or SB-P3G2 was bactericidal, while SB-P1G10 treatment never resulted in complete killing. The dose curves for the three compounds against clinical isolates were comparable to their respective dose curves in the laboratory strain of M. tuberculosis. SB-P8B2 and SB-P3G2 exhibited antibacterial activity against non-replicating bacilli under low oxygen conditions. SB-P3G2 and SB-P1G10 were assessed in acute short-term animal models of tuberculosis, which showed that SB-P3G2 treatment demonstrated activity against M. tuberculosis. Together, these studies reveal an in vitro- in vivo relationship of the 2,5,6-trisubstituted benzimidazoles that serves as a criterion for advancing this class of cell division inhibitors into more resource intensive in vivo efficacy models such as the long-term murine model of tuberculosis and Pre-IND PK/PD studies. Specifically, these studies are the first demonstration of efficacy and an in vitro–in vivo activity relationship for 2,5,6-trisubstituted benzimidazoles. The in vivo activity presented in this manuscript substantiates this class of cell division inhibitors as having potency and efficacy against M. tuberculosis. PMID:24746463

New Coumarin Derivatives as Potent Selective COX-2 Inhibitors: Synthesis, Anti-Inflammatory, QSAR, and Molecular Modeling Studies.

PubMed

Dawood, Dina H; Batran, Rasha Z; Farghaly, Thoraya A; Khedr, Mohammed A; Abdulla, Mohamed M

2015-12-01

Two new series of coumarin derivatives incorporating thiazoline and thiazolidinone moieties were designed, synthesized, and investigated in vivo for their anti-inflammatory activities using the carrageenan-induced rat paw edema model and in vitro for their inhibitory activities against the human cyclooxygenase (COX)-1 and COX-2 isoforms. Most of the synthesized compounds demonstrated exceptionally high in vivo anti-inflammatory activity and displayed superior GI safety profiles (0-7% ulceration) as compared to indomethacin. All the bioactive compounds showed in vitro high affinity and selectivity toward the COX-2 isoenzyme, compared to the reference celecoxib with IC50 values ranging from 0.31 to 0.78 μM. The ethyl thiosemicarbazone 2b, thiazoline derivatives 3a, 3b, 5b, 6a, and 7f, and the thiazolidinone compounds 8b and 9a showed the highest in vivo and in vitro anti-inflammatory activities with remarkable COX-2 selectivity. Quantitative structure-activity relationship study (QSAR) was done and resulted in a highly predictive power R(2) (0.908). A molecular docking study revealed a relationship between the docking affinity and the biological results. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selective interference with image retention and generation: evidence for the workspace model.

PubMed

van der Meulen, Marian; Logie, Robert H; Della Sala, Sergio

2009-08-01

We address three types of model of the relationship between working memory (WM) and long-term memory (LTM): (a) the gateway model, in which WM acts as a gateway between perceptual input and LTM; (b) the unitary model, in which WM is seen as the currently activated areas of LTM; and (c) the workspace model, in which perceptual input activates LTM, and WM acts as a separate workspace for processing and temporary retention of these activated traces. Predictions of these models were tested, focusing on visuospatial working memory and using dual-task methodology to combine two main tasks (visual short-term retention and image generation) with two interference tasks (irrelevant pictures and spatial tapping). The pictures selectively disrupted performance on the generation task, whereas the tapping selectively interfered with the retention task. Results are consistent with the predictions of the workspace model.

Quantification of Covariance in Tropical Cyclone Activity across Teleconnected Basins

NASA Astrophysics Data System (ADS)

Tolwinski-Ward, S. E.; Wang, D.

2015-12-01

Rigorous statistical quantification of natural hazard covariance across regions has important implications for risk management, and is also of fundamental scientific interest. We present a multivariate Bayesian Poisson regression model for inferring the covariance in tropical cyclone (TC) counts across multiple ocean basins and across Saffir-Simpson intensity categories. Such covariability results from the influence of large-scale modes of climate variability on local environments that can alternately suppress or enhance TC genesis and intensification, and our model also simultaneously quantifies the covariance of TC counts with various climatic modes in order to deduce the source of inter-basin TC covariability. The model explicitly treats the time-dependent uncertainty in observed maximum sustained wind data, and hence the nominal intensity category of each TC. Differences in annual TC counts as measured by different agencies are also formally addressed. The probabilistic output of the model can be probed for probabilistic answers to such questions as: - Does the relationship between different categories of TCs differ statistically by basin? - Which climatic predictors have significant relationships with TC activity in each basin? - Are the relationships between counts in different basins conditionally independent given the climatic predictors, or are there other factors at play affecting inter-basin covariability? - How can a portfolio of insured property be optimized across space to minimize risk? Although we present results of our model applied to TCs, the framework is generalizable to covariance estimation between multivariate counts of natural hazards across regions and/or across peril types.

The Communication, Awareness, Relationships and Empowerment (C.A.R.E.) Model: An Effective Tool for Engaging Urban Communities in Community-Based Participatory Research

PubMed Central

Ceasar, Joniqua; Peters-Lawrence, Marlene H.; Mitchell, Valerie; Powell-Wiley, Tiffany M.

2017-01-01

Little is known about recruitment methods for racial/ethnic minority populations from resource-limited areas for community-based health and needs assessments, particularly assessments that incorporate mobile health (mHealth) technology for characterizing physical activity and dietary intake. We examined whether the Communication, Awareness, Relationships and Empowerment (C.A.R.E.) model could reduce challenges recruiting and retaining participants from faith-based organizations in predominantly African American Washington, D.C. communities for a community-based assessment. Employing C.A.R.E. model elements, our diverse research team developed partnerships with churches, health organizations, academic institutions and governmental agencies. Through these partnerships, we cultivated a visible presence at community events, provided cardiovascular health education and remained accessible throughout the research process. Additionally, these relationships led to the creation of a community advisory board (CAB), which influenced the study’s design, implementation, and dissemination. Over thirteen months, 159 individuals were recruited for the study, 99 completed the initial assessment, and 81 used mHealth technology to self-monitor physical activity over 30 days. The culturally and historically sensitive C.A.R.E. model strategically engaged CAB members and study participants. It was essential for success in recruitment and retention of an at-risk, African American population and may be an effective model for researchers hoping to engage racial/ethnic minority populations living in urban communities. PMID:29160826

Vigorous Physical Activity, Mental Health, Perceived Stress, and Socializing Among College Students

PubMed Central

VanKim, Nicole A.; Nelson, Toben F.

2013-01-01

Purpose To examine cross-sectional associations between vigorous physical activity, mental health, perceived stress, and socializing among 4-year college students. Design A national cross-sectional sample of 4-year colleges in the United States. Setting Ninety-four 4-year colleges in the United States. Subjects A total of 14,804 undergraduate students. Measures Self-report vigorous physical activity, perceived stress (measured using the Cohen Perceived Stress Scale), mental health (measured using the SF-36), and socializing (assessed using self-report number of friends and hours spent socializing). Analysis Logistic regression models accounting for clustering within schools were estimated to examine the association between vigorous physical activity, mental health, perceived stress, and socializing. Adjusted models included high school vigorous physical activity and sociodemographic characteristics. Results Students who met vigorous physical activity recommendations were less likely to report poor mental health (adjusted odds ratio [OR]: .79; 95% confidence interval [CI]: .69, .90) and perceived stress (adjusted OR: .75; 95% CI: .67, .83) than students who did not meet recommendations. In addition, socializing partially mediated the relationship between vigorous physical activity, mental health, and perceived stress; however, race and sex did not moderate the relationship. Conclusion Interventions aiming to improve mental well-being of college students should also consider promoting physical activity. At least some of the positive benefits of physical activity may arise from social interactions. PMID:23470187

Examination of a muscular activity estimation model using a Bayesian network for the influence of an ankle foot orthosis.

PubMed

Inoue, Jun; Kawamura, Kazuya; Fujie, Masakatsu G

2012-01-01

In the present paper, we examine the appropriateness of a new model to examine the activity of the foot in gait. We developed an estimation model for foot-ankle muscular activity in the design of an ankle-foot orthosis by means of a statistical method. We chose three muscles for measuring muscular activity and built a Bayesian network model to confirm the appropriateness of the estimation model. We experimentally examined the normal gait of a non-disabled subject. We measured the muscular activity of the lower foot muscles using electromyography, the joint angles, and the pressure on each part of the sole. From these data, we obtained the causal relationship at every 10% level for these factors and built models for the stance phase, control term, and propulsive term. Our model has three advantages. First, it can express the influences that change during gait because we use 10% level nodes for each factor. Second, it can express the influences of factors that differ for low and high muscular-activity levels. Third, we created divided models that are able to reflect the actual features of gait. In evaluating the new model, we confirmed it is able to estimate all muscular activity level with an accuracy of over 90%.

Externalizing religious health beliefs and health and well-being outcomes.

PubMed

Hayward, R David; Krause, Neal; Ironson, Gail; Pargament, Kenneth I

2016-10-01

Certain religious beliefs related to perceptions of internal or external health control (including belief in the existence of miraculous healing, and beliefs deferring responsibility for health outcomes from the self and onto God) may be related to health behaviors and in turn to health outcomes. Using data from a nationally representative US survey of religion and health (N = 2948) this study evaluates a series of two structural equation models of the relationships between religious activity, externalizing religious health beliefs (belief in healing miracles and divine health deferral), health outcomes, and life satisfaction. Believing in healing miracles was related to greater divine health deferral. Greater divine health deferral was associated with poorer symptoms of physical health. Belief in miracles was related to greater life satisfaction. Comparison of coefficients across models indicated that externalizing beliefs had a significant suppressor effect on the relationship between religious activity and physical symptoms, but did not significantly mediate its relationship with life satisfaction. Religious beliefs emphasizing divine control over health outcomes may have negative consequences for health outcomes, although the same beliefs may contribute to a better sense of life satisfaction.

Do relationships exist between the scope and intensity of quality improvement activities and hospital operation performance? A 10-year observation in Taiwan.

PubMed

Chung, Kuo-Piao; Yu, Tsung-Hsien

2015-08-14

The relationship between the scope and intensity of quality improvement (QI) activities and hospital performance remains unclear. This study investigated the relationship between performance, external environment, and the scope and intensity of QI activities in hospitals. The study used a longitudinal observation. Data regarding the scope and intensity of QI activities were collected using a questionnaire survey among the administrative deputy superintendents / directors of quality management center in 139 hospitals. Hospital performance indicators were abstracted from the 2000-2009 national hospitals profiles. We adopted year 2000 as the baseline, and divided the study period into three 3-year periods. The Generalized Estimating Equations (GEE) model was used for the statistical analysis. Seventy-two hospitals responded to the survey, giving a response rate of 52%. The results showed a significant increase in the scope and intensity of QI activities between 2000 and 2009. The results also showed that the scope and intensity of a hospital's QI activities were associated with the scope and intensity of its competitors' QI activities in the previous period and its own prior performance. The scope of QI activities in the previous period was not significantly related to the selected hospital performance measures. However, the intensity of QI activities in the previous period showed a significant and positive relationship with the number of inpatients and the turnover of beds. The study demonstrates that the intensity of QI activities is associated with the external environment and the hospital's own performance in the previous period. Furthermore, some performance measures are associated with the intensity of the QI activities in the previous period.

Application of an in vitro OAT assay in drug design and optimization of renal clearance.

PubMed

Soars, Matthew G; Barton, Patrick; Elkin, Lisa L; Mosure, Kathleen W; Sproston, Joanne L; Riley, Robert J

2014-07-01

1. Optimization of renal clearance is a complex balance between passive and active processes mediated by renal transporters. This work aimed to characterize the interaction of a series of compounds with rat and human organic anion transporters (OATs) and develop quantitative structure-activity relationships (QSARs) to optimize renal clearance. 2. In vitro inhibition assays were established for human OAT1 and rat Oat3 and rat in vivo renal clearance was obtained. Statistically significant quantitative relationships were explored between the compounds' physical properties, their affinity for OAT1 and oat3 and the inter-relationship with unbound renal clearance (URC) in rat. 3. Many of the compounds were actively secreted and in vitro analysis demonstrated that these were ligands for rat and human OAT transporters (IC50 values ranging from <1 to >100 µM). Application of resultant QSAR models reduced renal clearance in the rat from 24 to <0.1 ml/min/kg. Data analysis indicated that the properties associated with increasing affinity at OATs are the same as those associated with reducing URC but orthogonal in nature. 4. This study has demonstrated that OAT inhibition data and QSAR models can be successfully used to optimize rat renal clearance in vivo and provide confidence of translation to humans.

QSAR, QSPR and QSRR in Terms of 3-D-MoRSE Descriptors for In Silico Screening of Clofibric Acid Analogues.

PubMed

Di Tullio, Maurizio; Maccallini, Cristina; Ammazzalorso, Alessandra; Giampietro, Letizia; Amoroso, Rosa; De Filippis, Barbara; Fantacuzzi, Marialuigia; Wiczling, Paweł; Kaliszan, Roman

2012-07-01

A series of 27 analogues of clofibric acid, mostly heteroarylalkanoic derivatives, have been analyzed by a novel high-throughput reversed-phase HPLC method employing combined gradient of eluent's pH and organic modifier content. The such determined hydrophobicity (lipophilicity) parameters, log kw , and acidity constants, pKa , were subjected to multiple regression analysis to get a QSRR (Quantitative StructureRetention Relationships) and a QSPR (Quantitative Structure-Property Relationships) equation, respectively, describing these pharmacokinetics-determining physicochemical parameters in terms of the calculation chemistry derived structural descriptors. The previously determined in vitro log EC50 values - transactivation activity towards PPARα (human Peroxisome Proliferator-Activated Receptor α) - have also been described in a QSAR (Quantitative StructureActivity Relationships) equation in terms of the 3-D-MoRSE descriptors (3D-Molecule Representation of Structures based on Electron diffraction descriptors). The QSAR model derived can serve for an a priori prediction of bioactivity in vitro of any designed analogue, whereas the QSRR and the QSPR models can be used to evaluate lipophilicity and acidity, respectively, of the compounds, and hence to rational guide selection of structures of proper pharmacokinetics. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Symptom variability, affect and physical activity in ambulatory persons with multiple sclerosis: Understanding patterns and time-bound relationships.

PubMed

Kasser, Susan L; Goldstein, Amanda; Wood, Phillip K; Sibold, Jeremy

2017-04-01

Individuals with multiple sclerosis (MS) experience a clinical course that is highly variable with daily fluctuations in symptoms significantly affecting functional ability and quality of life. Yet, understanding how MS symptoms co-vary and associate with physical and psychological health is unclear. The purpose of the study was to explore variability patterns and time-bound relationships across symptoms, affect, and physical activity in individuals with MS. The study employed a multivariate, replicated, single-subject repeated-measures (MRSRM) design and involved four individuals with MS. Mood, fatigue, pain, balance confidence, and losses of balance were measured daily over 28 days by self-report. Physical activity was also measured daily over this same time period via accelerometry. Dynamic factor analysis (DFA) was used to determine the dimensionality and lagged relationships across the variables. Person-specific models revealed considerable time-dependent co-variation patterns as well as pattern variation across subjects. Results also offered insight into distinct variability structures at varying levels of disability. Modeling person-level variability may be beneficial for addressing the heterogeneity of experiences in individuals with MS and for understanding temporal and dynamic interrelationships among perceived symptoms, affect, and health outcomes in this group. Copyright © 2016 Elsevier Inc. All rights reserved.

Cause-and-effect relationships in tandem swimmer models using transfer entropy

NASA Astrophysics Data System (ADS)

Peterson, Sean; Rosen, Maxwell; Gementzopoulos, Antonios; Zhang, Peng; Porfiri, Maurizio

2017-11-01

Swimming in a group affords a number of advantages to fish, including an enhanced ability to escape from predators, search for food, and mate. To study coordinated movements of fish, principled approaches are needed to unravel cause-and-effect relationships from raw-time series of multiple bodies moving in an encompassing fluid. In this work, we aim at demonstrating the validity of transfer entropy to elucidate cause-and-effect relationships in a fluid-structure interaction problem. Specifically, we consider two tandem airfoils in a uniform flow, wherein the pitching angle of one airfoil is actively controlled while the other is allowed to passively rotate. The active control alternates the pitch angle based upon an underlying two-state ergodic Markov process. We monitor the pitch angle of both the active and passive airfoils in time and demonstrate that transfer entropy can detect causality independent of which airfoil is actuated. The influence estimated by transfer entropy is found to be modulated by the distance between the two airfoils. The proposed data-driven technique offers a model-free perspective on fluid-structure interactions that can help illuminate the mechanisms of swimming in coordination. This work was supported by the National Science Foundation under Grant Numbers CBET-1332204 and CMMI-1433670.

The exercise and affect relationship: evidence for the dual-mode model and a modified opponent process theory.

PubMed

Markowitz, Sarah M; Arent, Shawn M

2010-10-01

This study examined the relationship between exertion level and affect using the framework of opponent-process theory and the dual-mode model, with the Activation-Deactivation Adjective Checklist and the State Anxiety Inventory among 14 active and 14 sedentary participants doing 20 min of treadmill exercise at speeds of 5% below, 5% above, and at lactate threshold (LT). We found a significant effect of time, condition, Time × Condition, and Time × Group, but no group, Group × Condition, or Time × Group × Condition effects, such that the 5% above LT condition produced a worsening of affect in-task compared with all other conditions whereas, across conditions, participants experienced in-task increases in energy and tension, and in-task decreases in tiredness and calmness relative to baseline. Posttask, participants experienced mood improvement (decreased tension, anxiety, and increased calmness) across conditions, with a 30-min delay in the above LT condition. These results partially support the dual-mode model and a modified opponent-process theory.

Poromechanics Parameters of Fluid-Saturated Chemically Active Fibrous Media Derived from a Micromechanical Approach.

PubMed

Misra, Anil; Parthasarathy, Ranganathan; Singh, Viraj; Spencer, Paulette

2013-01-01

The authors have derived macroscale poromechanics parameters for chemically active saturated fibrous media by combining microstructure-based homogenization with Hill's volume averaging. The stress-strain relationship of the dry fibrous media is first obtained by considering the fiber behavior. The constitutive relationships applicable to saturated media are then derived in the poromechanics framework using Hill's Lemmas. The advantage of this approach is that the resultant continuum model assumes a form suited to study porous materials, while retaining the effect of discrete fiber deformation. As a result, the model is able to predict the influence of microscale phenomena such as fiber buckling on the overall behavior, and in particular, on the poromechanics constants. The significance of the approach is demonstrated using the effect of drainage and fiber nonlinearity on monotonic compressive stress-strain behavior. The model predictions conform to the experimental observations for articular cartilage. The method can potentially be extended to other porous materials such as bone, clays, foams, and concrete.

Establishment of quantitative retention-activity model by optimized microemulsion liquid chromatography.

PubMed

Xu, Liyuan; Gao, Haoshi; Li, Liangxing; Li, Yinnong; Wang, Liuyun; Gao, Chongkai; Li, Ning

2016-12-23

The effective permeability coefficient is of theoretical and practical importance in evaluation of the bioavailability of drug candidates. However, most methods currently used to measure this coefficient are expensive and time-consuming. In this paper, we addressed these problems by proposing a new measurement method which is based on the microemulsion liquid chromatography. First, the parallel artificial membrane permeability assays model was used to determine the effective permeability of drug so that quantitative retention-activity relationships could be established, which were used to optimize the microemulsion liquid chromatography. The most effective microemulsion system used a mobile phase of 6.0% (w/w) Brij35, 6.6% (w/w) butanol, 0.8% (w/w) octanol, and 86.6% (w/w) phosphate buffer (pH 7.4). Next, support vector machine and back-propagation neural networks are employed to develop a quantitative retention-activity relationships model associated with the optimal microemulsion system, and used to improve the prediction ability. Finally, an adequate correlation between experimental value and predicted value is computed to verify the performance of the optimal model. The results indicate that the microemulsion liquid chromatography can serve as a possible alternative to the PAMPA method for determination of high-throughput permeability and simulation of biological processes. Copyright © 2016. Published by Elsevier B.V.

Synthetic cannabinoids: In silico prediction of the cannabinoid receptor 1 affinity by a quantitative structure-activity relationship model.

PubMed

Paulke, Alexander; Proschak, Ewgenij; Sommer, Kai; Achenbach, Janosch; Wunder, Cora; Toennes, Stefan W

2016-03-14

The number of new synthetic psychoactive compounds increase steadily. Among the group of these psychoactive compounds, the synthetic cannabinoids (SCBs) are most popular and serve as a substitute of herbal cannabis. More than 600 of these substances already exist. For some SCBs the in vitro cannabinoid receptor 1 (CB1) affinity is known, but for the majority it is unknown. A quantitative structure-activity relationship (QSAR) model was developed, which allows the determination of the SCBs affinity to CB1 (expressed as binding constant (Ki)) without reference substances. The chemically advance template search descriptor was used for vector representation of the compound structures. The similarity between two molecules was calculated using the Feature-Pair Distribution Similarity. The Ki values were calculated using the Inverse Distance Weighting method. The prediction model was validated using a cross validation procedure. The predicted Ki values of some new SCBs were in a range between 20 (considerably higher affinity to CB1 than THC) to 468 (considerably lower affinity to CB1 than THC). The present QSAR model can serve as a simple, fast and cheap tool to get a first hint of the biological activity of new synthetic cannabinoids or of other new psychoactive compounds. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Reduced density gradient as a novel approach for estimating QSAR descriptors, and its application to 1, 4-dihydropyridine derivatives with potential antihypertensive effects.

PubMed

Jardínez, Christiaan; Vela, Alberto; Cruz-Borbolla, Julián; Alvarez-Mendez, Rodrigo J; Alvarado-Rodríguez, José G

2016-12-01

The relationship between the chemical structure and biological activity (log IC 50 ) of 40 derivatives of 1,4-dihydropyridines (DHPs) was studied using density functional theory (DFT) and multiple linear regression analysis methods. With the aim of improving the quantitative structure-activity relationship (QSAR) model, the reduced density gradient s( r) of the optimized equilibrium geometries was used as a descriptor to include weak non-covalent interactions. The QSAR model highlights the correlation between the log IC 50 with highest molecular orbital energy (E HOMO ), molecular volume (V), partition coefficient (log P), non-covalent interactions NCI(H4-G) and the dual descriptor [Δf(r)]. The model yielded values of R 2 =79.57 and Q 2 =69.67 that were validated with the next four internal analytical validations DK=0.076, DQ=-0.006, R P =0.056, and R N =0.000, and the external validation Q 2 boot =64.26. The QSAR model found can be used to estimate biological activity with high reliability in new compounds based on a DHP series. Graphical abstract The good correlation between the log IC 50 with the NCI (H4-G) estimated by the reduced density gradient approach of the DHP derivatives.

The ISO Edi Conceptual Model Activity and Its Relationship to OSI.

ERIC Educational Resources Information Center

Fincher, Judith A.

1990-01-01

The edi conceptual model is being developed to define common structures, services, and processes that syntax-specific standards like X12 and EDIFACT could adopt. Open Systems Interconnection (OSI) is of interest to edi because of its potential to help enable global interoperability across Electronic Data Interchange (EDI) functional groups. A…

Investigation of antigen-antibody interactions of sulfonamides with a monoclonal antibody in a fluorescence polarization immunoassay using 3D-QSAR models

USDA-ARS?s Scientific Manuscript database

A three-dimensional quantitative structure-activity relationship (3D-QSAR) model of sulfonamide analogs binding a monoclonal antibody (MAbSMR) produced against sulfamerazine was carried out by Distance Comparison (DISCOtech), comparative molecular field analysis (CoMFA), and comparative molecular si...

Toxicity challenges in environmental chemicals: Prediction of human plasma protein binding through quantitative structure-activity relationship (QSAR) models (2016 IVIVE Workshop Proceedings)

EPA Science Inventory

Physiologically based pharmacokinetic (PBPK) models bridge the gap between in vitro assays and in vivo effects by accounting for the adsorption, distribution, metabolism, and excretion of xenobiotics, which is especially useful in the assessment of human toxicity. Quantitative st...

Testing a Model Linking Environmental Hope and Self-Control with Students' Positive Emotions and Environmental Behavior

ERIC Educational Resources Information Center

Kerret, Dorit; Orkibi, Hod; Ronen, Tammie

2016-01-01

This study examined a moderated mediation model with 254 Israeli junior high school students, hypothesizing that students' environmental hope would simultaneously mediate the relationship between their engagement in school-based environmental activities (green engagement) and their environmental behavior as well as their positivity ratio, but that…

The impact of social support, unit cohesion, and trait resilience on PTSD in treatment-seeking military personnel with PTSD: The role of posttraumatic cognitions.

PubMed

Zang, Yinyin; Gallagher, Thea; McLean, Carmen P; Tannahill, Hallie S; Yarvis, Jeffrey S; Foa, Edna B

2017-03-01

The personal resources of social support, unit cohesion, and trait resilience have been found to be associated with posttraumatic stress disorder (PTSD) severity among military personnel. However, the underlying mechanisms of these relationships are unclear. We hypothesized that negative posttraumatic cognitions, which are associated with PTSD, mediate the relationships between these personal resources and PTSD. The relationship between PTSD symptom severity and a latent factor comprised of social support, unit cohesion, and trait resilience was evaluated using cross-sectional data from 366 treatment-seeking active duty military personnel with PTSD following deployments to or near Iraq or Afghanistan. Structural equation modeling (SEM) was used to test whether posttraumatic cognitions mediated this relationship. The SEM model indicated that (1) a robust latent variable named personal resources (indicated by social support, unit cohesion, and trait resilience) was negatively associated with PTSD severity; (2) personal resources were negatively associated with negative posttraumatic cognitions; (3) negative posttraumatic cognitions fully mediated the association between personal resources and PTSD severity. The final SEM mediation model showed a highly satisfactory fit [χ 2 (22) = 16.344, p = 0.798; χ 2 /df = 0.743; CFI = 1; RMSEA = 0.000]. These findings suggest that among active duty military personnel seeking treatment for PTSD, personal resources (social support, unit cohesion, and trait resilience) may mitigate PTSD severity by reducing negative posttraumatic cognitions. Copyright © 2016 Elsevier Ltd. All rights reserved.

The mechanics of fault-bend folding and tear-fault systems in the Niger Delta

NASA Astrophysics Data System (ADS)

Benesh, Nathan Philip

This dissertation investigates the mechanics of fault-bend folding using the discrete element method (DEM) and explores the nature of tear-fault systems in the deep-water Niger Delta fold-and-thrust belt. In Chapter 1, we employ the DEM to investigate the development of growth structures in anticlinal fault-bend folds. This work was inspired by observations that growth strata in active folds show a pronounced upward decrease in bed dip, in contrast to traditional kinematic fault-bend fold models. Our analysis shows that the modeled folds grow largely by parallel folding as specified by the kinematic theory; however, the process of folding over a broad axial surface zone yields a component of fold growth by limb rotation that is consistent with the patterns observed in natural folds. This result has important implications for how growth structures can he used to constrain slip and paleo-earthquake ages on active blind-thrust faults. In Chapter 2, we expand our DEM study to investigate the development of a wider range of fault-bend folds. We examine the influence of mechanical stratigraphy and quantitatively compare our models with the relationships between fold and fault shape prescribed by the kinematic theory. While the synclinal fault-bend models closely match the kinematic theory, the modeled anticlinal fault-bend folds show robust behavior that is distinct from the kinematic theory. Specifically, we observe that modeled structures maintain a linear relationship between fold shape (gamma) and fault-horizon cutoff angle (theta), rather than expressing the non-linear relationship with two distinct modes of anticlinal folding that is prescribed by the kinematic theory. These observations lead to a revised quantitative relationship for fault-bend folds that can serve as a useful interpretation tool. Finally, in Chapter 3, we examine the 3D relationships of tear- and thrust-fault systems in the western, deep-water Niger Delta. Using 3D seismic reflection data and new map-based structural restoration techniques, we find that the tear faults have distinct displacement patterns that distinguish them from conventional strike-slip faults and reflect their roles in accommodating displacement gradients within the fold-and-thrust belt.

Antimalarial Pyrido[1,2-a]benzimidazoles: Lead Optimization, Parasite Life Cycle Stage Profile, Mechanistic Evaluation, Killing Kinetics, and in Vivo Oral Efficacy in a Mouse Model.

PubMed

Singh, Kawaljit; Okombo, John; Brunschwig, Christel; Ndubi, Ferdinand; Barnard, Linley; Wilkinson, Chad; Njogu, Peter M; Njoroge, Mathew; Laing, Lizahn; Machado, Marta; Prudêncio, Miguel; Reader, Janette; Botha, Mariette; Nondaba, Sindisiwe; Birkholtz, Lyn-Marie; Lauterbach, Sonja; Churchyard, Alisje; Coetzer, Theresa L; Burrows, Jeremy N; Yeates, Clive; Denti, Paolo; Wiesner, Lubbe; Egan, Timothy J; Wittlin, Sergio; Chibale, Kelly

2017-02-23

Further structure-activity relationship (SAR) studies on the recently identified pyrido[1,2-a]benzimidazole (PBI) antimalarials have led to the identification of potent, metabolically stable compounds with improved in vivo oral efficacy in the P. berghei mouse model and additional activity against parasite liver and gametocyte stages, making them potential candidates for preclinical development. Inhibition of hemozoin formation possibly contributes to the mechanism of action.

Bifurcation analysis of the regulation of nociceptive neuronal activity

NASA Astrophysics Data System (ADS)

Dik, O. E.

2017-11-01

A model of the membrane of a nociceptive neuron from a rat dorsal ganglion has been used to address the problem of analyzing the regulation of nociceptive signals by 5-hydroxy-γ-pyrone-2-carboxylic acid, which is the active pharmaceutic ingredient of the analgesic Anoceptin. The study has applied bifurcation analysis to report the relationship between the values of model parameters and the type of problem solution before and after the parameters change in response to analgesic modulation.

Assessment of Cognitively Stimulating Activity in a Spanish Population.

PubMed

Morales Ortiz, Manuel; Fernández, Aaron

2018-05-01

Theoretical models of active ageing and cognitive reserve emphasize the importance of leading an active life to delay age-related cognitive deterioration and maintain good levels of well-being and personal satisfaction in the elderly. The objective of this research was to construct a scale to measure cognitively stimulating activities (CSA) in the Spanish language. The sample consisted of a total of 453 older persons. The scale was constructed from a list of 28 items and validated using structural equation models. The scale obtained showed a negative correlation with age and a positive correlation with education and physical activity. Using hierarchical regression models, CSAs were found to have a significant effect on attention when controlling for the effect of age and education. Likewise, a significant interaction between age and CSA was found on the measure of episodic memory. The validated CSA scale will enable the relationships between changes in cognitive functions and stimulating activities to be studied.

Sexual risk behavior among youth: modeling the influence of prosocial activities and socioeconomic factors.

PubMed

Ramirez-Valles, J; Zimmerman, M A; Newcomb, M D

1998-09-01

Sexual activity among high-school-aged youths has steadily increased since the 1970s, emerging as a significant public health concern. Yet, patterns of youth sexual risk behavior are shaped by social class, race, and gender. Based on sociological theories of financial deprivation and collective socialization, we develop and test a model of the relationships among neighborhood poverty; family structure and social class position; parental involvement; prosocial activities; race; and gender as they predict youth sexual risk behavior. We employ structural equation modeling to test this model on a cross-sectional sample of 370 sexually active high-school students from a midwestern city; 57 percent (n = 209) are males and 86 percent are African American. We find that family structure indirectly predicts sexual risk behavior through neighborhood poverty, parental involvement, and prosocial activities. In addition, family class position indirectly predicts sexual risk behavior through neighborhood poverty and prosocial activities. We address implications for theory and health promotion.

Biomacromolecular quantitative structure-activity relationship (BioQSAR): a proof-of-concept study on the modeling, prediction and interpretation of protein-protein binding affinity.

PubMed

Zhou, Peng; Wang, Congcong; Tian, Feifei; Ren, Yanrong; Yang, Chao; Huang, Jian

2013-01-01

Quantitative structure-activity relationship (QSAR), a regression modeling methodology that establishes statistical correlation between structure feature and apparent behavior for a series of congeneric molecules quantitatively, has been widely used to evaluate the activity, toxicity and property of various small-molecule compounds such as drugs, toxicants and surfactants. However, it is surprising to see that such useful technique has only very limited applications to biomacromolecules, albeit the solved 3D atom-resolution structures of proteins, nucleic acids and their complexes have accumulated rapidly in past decades. Here, we present a proof-of-concept paradigm for the modeling, prediction and interpretation of the binding affinity of 144 sequence-nonredundant, structure-available and affinity-known protein complexes (Kastritis et al. Protein Sci 20:482-491, 2011) using a biomacromolecular QSAR (BioQSAR) scheme. We demonstrate that the modeling performance and predictive power of BioQSAR are comparable to or even better than that of traditional knowledge-based strategies, mechanism-type methods and empirical scoring algorithms, while BioQSAR possesses certain additional features compared to the traditional methods, such as adaptability, interpretability, deep-validation and high-efficiency. The BioQSAR scheme could be readily modified to infer the biological behavior and functions of other biomacromolecules, if their X-ray crystal structures, NMR conformation assemblies or computationally modeled structures are available.

The relationship between physical activity levels and pain in children with juvenile idiopathic arthritis.

PubMed

Limenis, Elizaveta; Grosbein, Haddas A; Feldman, Brian M

2014-02-01

Pain and reduced physical activity levels are common in children with juvenile idiopathic arthritis (JIA). Currently, there is no consensus about the role of physical activity in managing pain in JIA. The purpose of our study was to assess the relationship between physical activity level and pain in children ages 11 to 18 years with JIA. A random sample of 50 patients with JIA were approached by mailed questionnaires. Physical activity was determined using the Physical Activity Questionnaire (PAQ). Pain measures included the Numerical Rating Scale (pain severity), SUPER-KIDZ body diagram (number of painful areas), and the Child Activities Limitations Inventory-21 (pain interference). Generalized linear models were used to assess the relationship between physical activity and pain, as well as the roles of sex and age. The response rate was 84%. Thirty-four respondents completed the questionnaire package. The median age was 15 years. The mean PAQ score was 2.16/5. Physical activity declines with increasing age in youth with JIA (r = 0.53, p = 0.0014). Lower physical activity is associated with greater pain interference (r = 0.39, p = 0.0217) and more severe pain (r = 0.35, p = 0.0422). Children with JIA report significantly less activity than healthy children based on PAQ scores, with physical activity declining throughout adolescence. Physical activity is inversely related to pain interference and severity in children with JIA. Our findings suggest that physical activity interventions may play an important role in the management of pain in JIA.

The quantitative structure-insecticidal activity relationships from plant derived compounds against chikungunya and zika Aedes aegypti (Diptera:Culicidae) vector.

PubMed

Saavedra, Laura M; Romanelli, Gustavo P; Rozo, Ciro E; Duchowicz, Pablo R

2018-01-01

The insecticidal activity of a series of 62 plant derived molecules against the chikungunya, dengue and zika vector, the Aedes aegypti (Diptera:Culicidae) mosquito, is subjected to a Quantitative Structure-Activity Relationships (QSAR) analysis. The Replacement Method (RM) variable subset selection technique based on Multivariable Linear Regression (MLR) proves to be successful for exploring 4885 molecular descriptors calculated with Dragon 6. The predictive capability of the obtained models is confirmed through an external test set of compounds, Leave-One-Out (LOO) cross-validation and Y-Randomization. The present study constitutes a first necessary computational step for designing less toxic insecticides. Copyright © 2017 Elsevier B.V. All rights reserved.

The relationship between depressive symptoms, diabetes symptoms, and self-management among an urban, low-income Latino population.

PubMed

Nguyen, Annie L; Green, Janelle; Enguidanos, Susan

2015-01-01

To investigate the prevalence of depression symptoms among Latinos with diabetes following transition from hospital to home and the relationship of depressive symptoms to diabetes symptom severity and self-management activities. 203 Latino patients with diagnosed diabetes completed a survey assessing depressive symptoms (PHQ-9), diabetes symptom severity, and diabetes self-management activities (SDSCA). Characteristics and diabetes outcomes between patients with and without probable major depression were compared. Associations between PHQ-9 scores and diabetes outcomes were assessed. Multivariate regression models evaluated the relationship between depressive symptoms and diabetes outcomes and exercise after controlling for patient characteristics. 31.5% of participants indicated probable major depression (PHQ-9≥10). More severe diabetes symptoms and less reported exercise were associated with higher PHQ-9 scores. Regression models showed no relationship between self-management and depression. More severe diabetes symptoms were significantly associated with being female, married, and having probable major depression. Odds of exercising were reduced by 6% for every one-unit increase in PHQ-9 score. The prevalence of probable depressive symptoms is high in this population. Having depressive symptoms is an indicator of poorer diabetes symptoms. Screening for depressive symptoms may help identify individuals who need additional support with diabetes symptom and self-management. Copyright © 2015 Elsevier Inc. All rights reserved.

A review of the 11-year solar cycle, the QBO, and the atmosphere relationship

NASA Technical Reports Server (NTRS)

Chanin, M. L.

1989-01-01

The papers published by Labitzke (1987) and by Labitzke and Van Loon (1988) indicated that the separation of Winter stratospheric data according to the phase of the Quasi-Biennial Oscillation (Q.B.O.) led to a largely improved relationship with the 11 year solar cycle. Since then, this possible relationship has been studied and extended from the surface to the lower thermosphere and its extension to other seasons is in progress. An opportunity is provided to review the state of the problem and to attempt to give a general view of the experimentally observed responses of the atmosphere to solar activity, when considering the phases of the Q.B.O. After a brief recall of the relationship discovered in the winter stratosphere, its extension downwards, upwards and to the other seasons are successively reviewed. The existing models are not adequate right now to represent the solar influence as they only take into account the change in UV flux, but before being able to use the large scale dynamics in a coupled radiative photochemical model, one needs to understand the mechanism able to explain the forcing from the lower atmosphere or the surface which could be induced by a change in solar activity.

Psychometric properties of the Spanish version of the Passion Scale.

PubMed

Chamarro, Andrés; Penelo, Eva; Fornieles, Albert; Oberst, Ursula; Vallerand, Robert J; Fernández-Castro, Jordi

2015-01-01

Passion has been shown to be involved in psychological processes that emerge in diverse human activities like physical activity and sports, work, leisure, videogaming, pathological gambling, and interpersonal relationships. We aimed to present evidence of validity and internal consistency of the Passion Scale in Spanish based on the Dualistic Model of Passion, comprising harmonious and obsessive dimensions. The sample comprised 1,007 participants (350 females and 657 males), aged 16-65 (Md= 30.0 years). Exploratory Structural Equation Modeling (ESEM), measurement invariance and Multiple-Cause-Multiple-Indicator models (MIMIC) were used. Fit for the ESEM 2-factor solution was acceptable. Near full or partial measurement invariance across sex, type of activity, and age was supported. Relationships between both harmonious and obsessive dimensions and the external variables considered (age, sex, and criterion items) reasonably replicated those found in previous studies. Both scale scores showed adequate internal consistency (α = .81). Empirical evidence for the validity and internal consistency of the Spanish version of the Passion Scale is satisfactory and reveals that the scale is comparable to the English and French versions. Therefore, the Passion Scale can be used in research conducted in Spanish.

The morphology of flare phenomena, magnetic fields, and electric currents in active regions. III - NOAA active region 6233 (1990 August)

NASA Technical Reports Server (NTRS)

De La Beaujardiere, J.-F.; Canfield, Richard C.; Leka, K. D.

1993-01-01

We investigate the spatial relationship between vertical electric currents and flare phenomena in NOAA Active Region 6233, which was observed 1990, August 28-31 at Mees Solar Observatory. The two flares studied are the 1N/M1.8 flare on August 28, 22:30 UT and the 1N/M1.6 flare on August 29, 20:35 UT. Using Stokes polarimetry we make magnetograms of the region and compute the vertical current density. Using H-alpha imaging spectroscopy we identify sites of intense nonthermal electron precipitation or of high coronal pressure. The precipitation in these flares is barely strong enough to be detectable. We find that both precipitation and high pressure tend to occur near vertical currents, but that neither phenomenon is cospatial with current maxima. In contrast with the conclusion of other authors, we argue that these observations do not support a current-interruption model for flares, unless the relevant currents are primarily horizontal. The magnetic morphology and temporal evolution of these flares suggest that an erupting filament model may be relevant, but this model does not explicitly predict the relationship between precipitation, high pressure, and vertical currents.

Social influences on eating and physical activity behaviours of urban, minority youths.

PubMed

Anderson Steeves, Elizabeth T; Johnson, Katherine A; Pollard, Suzanne L; Jones-Smith, Jessica; Pollack, Keshia; Lindstrom Johnson, Sarah; Hopkins, Laura; Gittelsohn, Joel

2016-12-01

Social relationships can impact youths' eating and physical activity behaviours; however, the best strategies for intervening in the social environment are unknown. The objectives of the present study were to provide in-depth information on the social roles that youths' parents and friends play related to eating and physical activity behaviours and to explore the impact of other social relationships on youths' eating and physical activity behaviours. Convergent parallel mixed-methods design. Low-income, African American, food desert neighbourhoods in Baltimore City, MD, USA. Data were collected from 297 youths (53 % female, 91 % African American, mean age 12·3 (sd 1·5) years) using structured questionnaires and combined with in-depth interviews from thirty-eight youths (42 % female, 97 % African American, mean age 11·4 (sd 1·5) years) and ten parents (80 % female, 50 % single heads of house, 100 % African American). Combined interpretation of the results found that parents and caregivers have multiple, dynamic roles influencing youths' eating and physical activity behaviours, such as creating health-promoting rules, managing the home food environment and serving as a role model for physical activity. Other social relationships have specific, but limited roles. For example, friends served as partners for physical activity, aunts provided exposure to novel food experiences, and teachers and doctors provided information related to eating and physical activity. Obesity prevention programmes should consider minority youths' perceptions of social roles when designing interventions. Specifically, future research is needed to test the effectiveness of intervention strategies that enhance or expand the supportive roles played by social relationships.

Parental Perceptions of the Social Environment Are Inversely Related to Constraint of Adolescents’ Neighborhood Physical Activity

PubMed Central

Kepper, Maura; Broyles, Stephanie; Scribner, Richard; Tseng, Tung-Sung; Zabaleta, Jovanny; Griffiths, Lauren; Sothern, Melinda

2016-01-01

Background: The current study examined relationships between the neighborhood social environment (parental perceived collective efficacy (PCE)), constrained behaviors (e.g., avoidance or defensive behaviors) and adolescent offspring neighborhood physical activity in low- versus high-incivility neighborhoods. Methods: Adolescents (n = 71; 11–18 years (14.2, SD ± 1.6); male = 37 (52%); non-white = 24 (33.8%); low-income = 20 (29%); overweight/obese = 40 (56%)) and their parents/guardians enrolled in the Molecular and Social Determinants of Obesity in Developing Youth study were included in the current study. Questionnaires measured parents’/guardians’ PCE, constrained outdoor play practices and offspring neighborhood physical activity. Systematic social observation performed at the parcel-level using Google Street View assessed neighborhood incivilities. t-tests and chi-square tests determined differences by incivilities. Multilevel regression models examined relationships between PCE and: (1) constrained behaviors; and (2) neighborhood physical activity. The Hayes (2013) macro determined the mediating role of constrained behaviors. Results: Parents who had higher PCE reported lower levels of avoidance (p = 0.04) and defensive (p = 0.05) behaviors. However, demographic variables (i.e., gender, race and annual household income) limited these results. The direct relationship between PCE and parent-reported neighborhood physical activity was statistically significant in high-incivility neighborhoods only. Neither avoidance nor defensive behavior mediated the relationship between PCE and neighborhood physical activity. Conclusions: PCE influences parenting behaviors related to youth physical activity. Community-based programs that seek to facilitate social cohesion and control may be needed to increase adolescents’ physical activity. PMID:28009839

QSAR modeling of cumulative environmental end-points for the prioritization of hazardous chemicals.

PubMed

Gramatica, Paola; Papa, Ester; Sangion, Alessandro

2018-01-24

The hazard of chemicals in the environment is inherently related to the molecular structure and derives simultaneously from various chemical properties/activities/reactivities. Models based on Quantitative Structure Activity Relationships (QSARs) are useful to screen, rank and prioritize chemicals that may have an adverse impact on humans and the environment. This paper reviews a selection of QSAR models (based on theoretical molecular descriptors) developed for cumulative multivariate endpoints, which were derived by mathematical combination of multiple effects and properties. The cumulative end-points provide an integrated holistic point of view to address environmentally relevant properties of chemicals.

Effects of Activation Energy to Transient Response of Semiconductor Gas Sensor

NASA Astrophysics Data System (ADS)

Fujimoto, Akira; Ohtani, Tatsuki

The smell classifiable gas sensor will be desired for many applications such as gas detection alarms, process controls for food production and so on. We have tried to realize the sensor using transient responses of semiconductor gas sensor consisting of tin dioxide and pointed out that the sensor gave us different transient responses for kinds of gas. Results of model calculation showed the activation energy of chemical reaction on the sensor surface strongly depended on the transient response. We tried to estimate the activation energies by molecular orbital calculation with SnO2 Cluster. The results show that there is a liner relationship between the gradient of the transient responses and activation energies for carboxylic and alcoholic gases. Transient response will be predicted from activation energy in the same kind of gas and the smell discrimination by single semiconductor gas sensor will be realized by this relationship.

Gender differences in the relationship of weight-based stigmatisation with motivation to exercise and physical activity in overweight individuals

PubMed Central

Sattler, Krystal M; Deane, Frank P; Tapsell, Linda; Kelly, Peter J

2018-01-01

Weight stigma is related to lower levels of motivation to exercise in overweight and obesity. This study explored the nature of the relationship between stigma, motivation to exercise and physical activity while accounting for gender differences. Participants were 439 adults with overweight and obesity (mean body mass index = 32.18 kg/m2, standard deviation = 4.09 kg/m2). Females reported significantly more frequent stigma experiences than males. Mediation models found a conditional direct effect of weight stigma for males, with higher frequency of stigma experiences related to higher levels of walking and vigorous physical activity. A conditional indirect effect was found for females for walking, moderate and vigorous levels of physical activity, with higher weight stigma related to lower autonomous motivation, and lower levels of physical activity. Findings suggest that males and females are affected differently by weight-stigma experiences. PMID:29552349

Parabolic quantitative structure-activity relationships and photodynamic therapy: application of a three-compartment model with clearance to the in vivo quantitative structure-activity relationships of a congeneric series of pyropheophorbide derivatives used as photosensitizers for photodynamic therapy.

PubMed

Potter, W R; Henderson, B W; Bellnier, D A; Pandey, R K; Vaughan, L A; Weishaupt, K R; Dougherty, T J

1999-11-01

An open three-compartment pharmacokinetic model was applied to the in vivo quantitative structure-activity relationship (QSAR) data of a homologous series of pyropheophorbide photosensitizers for photodynamic therapy (PDT). The physical model was a lipid compartment sandwiched between two identical aqueous compartments. The first compartment was assumed to clear irreversibly at a rate K0. The measured octanol-water partition coefficients, P(i) (where i is the number of carbons in the alkyl chain) and the clearance rate K0 determined the clearance kinetics of the drugs. Solving the coupled differential equations of the three-compartment model produced clearance kinetics for each of the sensitizers in each of the compartments. The third compartment was found to contain the target of PDT. This series of compounds is quite lipophilic. Therefore these drugs are found mainly in the second compartment. The drug level in the third compartment represents a small fraction of the tissue level and is thus not accessible to direct measurement by extraction. The second compartment of the model accurately predicted the clearance from the serum of mice of the hexyl ether of pyropheophorbide a, one member of this series of compounds. The diffusion and clearance rate constants were those found by fitting the pharmacokinetics of the third compartment to the QSAR data. This result validated the magnitude and mechanistic significance of the rate constants used to model the QSAR data. The PDT response to dose theory was applied to the kinetic behavior of the target compartment drug concentration. This produced a pharmacokinetic-based function connecting PDT response to dose as a function of time postinjection. This mechanistic dose-response function was fitted to published, single time point QSAR data for the pheophorbides. As a result, the PDT target threshold dose together with the predicted QSAR as a function of time postinjection was found.

A unified internal model theory to resolve the paradox of active versus passive self-motion sensation

PubMed Central

Angelaki, Dora E

2017-01-01

Brainstem and cerebellar neurons implement an internal model to accurately estimate self-motion during externally generated (‘passive’) movements. However, these neurons show reduced responses during self-generated (‘active’) movements, indicating that predicted sensory consequences of motor commands cancel sensory signals. Remarkably, the computational processes underlying sensory prediction during active motion and their relationship to internal model computations during passive movements remain unknown. We construct a Kalman filter that incorporates motor commands into a previously established model of optimal passive self-motion estimation. The simulated sensory error and feedback signals match experimentally measured neuronal responses during active and passive head and trunk rotations and translations. We conclude that a single sensory internal model can combine motor commands with vestibular and proprioceptive signals optimally. Thus, although neurons carrying sensory prediction error or feedback signals show attenuated modulation, the sensory cues and internal model are both engaged and critically important for accurate self-motion estimation during active head movements. PMID:29043978

Modeling Coronal Response in Decaying Active Regions with Magnetic Flux Transport and Steady Heating

NASA Astrophysics Data System (ADS)

Ugarte-Urra, Ignacio; Warren, Harry P.; Upton, Lisa A.; Young, Peter R.

2017-09-01

We present new measurements of the dependence of the extreme ultraviolet (EUV) radiance on the total magnetic flux in active regions as obtained from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. Using observations of nine active regions tracked along different stages of evolution, we extend the known radiance—magnetic flux power-law relationship (I\\propto {{{Φ }}}α ) to the AIA 335 Å passband, and the Fe xviii 93.93 Å spectral line in the 94 Å passband. We find that the total unsigned magnetic flux divided by the polarity separation ({{Φ }}/D) is a better indicator of radiance for the Fe xviii line with a slope of α =3.22+/- 0.03. We then use these results to test our current understanding of magnetic flux evolution and coronal heating. We use magnetograms from the simulated decay of these active regions produced by the Advective Flux Transport model as boundary conditions for potential extrapolations of the magnetic field in the corona. We then model the hydrodynamics of each individual field line with the Enthalpy-based Thermal Evolution of Loops model with steady heating scaled as the ratio of the average field strength and the length (\\bar{B}/L) and render the Fe xviii and 335 Å emission. We find that steady heating is able to partially reproduce the magnitudes and slopes of the EUV radiance—magnetic flux relationships and discuss how impulsive heating can help reconcile the discrepancies. This study demonstrates that combined models of magnetic flux transport, magnetic topology, and heating can yield realistic estimates for the decay of active region radiances with time.

The mediational role of physical activity, social contact and stroke on the association between age, education, employment and dementia in an Asian older adult population.

PubMed

Abdin, Edimansyah; Chong, Siow Ann; Peh, Chao Xu; Vaingankar, Janhavi Ajit; Chua, Boon Yiang; Verma, Swapna; Jeyagurunathan, Anitha; Shafie, Saleha; Subramaniam, Mythily

2017-03-20

Our study aimed to investigate the pathways by which socio-demographic factors, modifiable health and lifestyle risk factors influence each other, and subsequently, lead to dementia. We used data from the Well-being of the Singapore Elderly study, a nationally representative survey of the older adult population aged 60 years and above in Singapore. Dementia diagnosis was established using 10/66 dementia criteria. Structural equation modelling (SEM) without latent variable was applied to confirm the hypothesized model. The results of SEM supported the hypothesized model (χ 2 = 14.999, df = 10, p = 0.132). The final model showed that those aged 75-84 years and 85 years and over (vs. 60-74 years), having no formal education, who had completed primary or secondary education (vs. completed tertiary), who were homemakers and retired (vs. paid work), and with a history of stroke were directly associated with higher odds of having dementia, while those who had more frequent contact with friends and neighbors as well as being physically active were directly associated with lower odds of having dementia diagnosis. The study also found that physical activity, more frequent contact with friends and stroke played a significant role as mediators in these relationships. The overall pathways model explained 57.7% of the variance in dementia. Our results suggest that physical activity, social contact and stroke were potential mediators in the relationship between age, education, employment and dementia. Intervention programmes focusing on physical activity such as exercise and social contact may be useful in reducing the risk of dementia among older adults.

How Object, Situation and Personality Shape Human Attitude in Learning: An Activity Perspective and a Multilevel Modeling Approach

ERIC Educational Resources Information Center

Sun, Jun

2009-01-01

Based on Activity Theory, this article examines attitude formation in human learning as shaped by the experiences of individual learners with various learning objects in particular learning contexts. It hypothesizes that a learner's object-related perceptions, personality traits and situational perceptions may have different relationships with the…

Peers' Perceived Support, Student Engagement in Academic Activities and Life Satisfaction: A Structural Equation Modeling Approach

ERIC Educational Resources Information Center

Hakimzadeh, Rezvan; Besharat, Mohammad-Ali; Khaleghinezhad, Seyed Ali; Ghorban Jahromi, Reza

2016-01-01

This study investigates the relationships among peers' perceived support, life satisfaction, and student engagement in academic activities. Three hundred and fifteen Iranian students (172 boys and 143 girls) who were studying in one suburb of Tehran participated in this study. All participants were asked to complete Peers' Perceived Support scale…

Modeling a Neural Network as a Teaching Tool for the Learning of the Structure-Function Relationship

ERIC Educational Resources Information Center

Salinas, Dino G.; Acevedo, Cristian; Gomez, Christian R.

2010-01-01

The authors describe an activity they have created in which students can visualize a theoretical neural network whose states evolve according to a well-known simple law. This activity provided an uncomplicated approach to a paradigm commonly represented through complex mathematical formulation. From their observations, students learned many basic…

Predicting Adolescents' Organized Activity Involvement: The Role of Maternal Depression History, Family Relationship Quality, and Adolescent Cognitions

ERIC Educational Resources Information Center

Bohnert, Amy M.; Martin, Nina C.; Garber, Judy

2007-01-01

Although the potential benefits of organized activity involvement during high school have been documented, little is known about what familial and individual characteristics are associated with higher levels of participation. Using structural equation modeling, this longitudinal study examined the extent to which maternal depression history (i.e.,…

College Students' Physical Activity and Health-Related Quality of Life: An Achievement Goal Perspective

ERIC Educational Resources Information Center

Zhang, Tao; Xiang, Ping; Gu, Xiangli; Rose, Melanie

2016-01-01

Purpose: The 2 × 2 achievement goal model, including the mastery-approach, mastery-avoidance, performance-approach, and performance-avoidance goal orientations, has recently been used to explain motivational outcomes in physical activity. This study attempted to examine the relationships among 2 × 2 achievement goal orientations, physical…

Structure-affinity relationship of the interaction between phenolic acids and their derivatives and β-lactoglobulin and effect on antioxidant activity.

PubMed

Wu, Simin; Zhang, Yunyue; Ren, Fazheng; Qin, Yinghui; Liu, Jiaxin; Liu, Jingwen; Wang, Qingyu; Zhang, Hao

2018-04-15

In this study, 71 phenolic acids and their derivatives were used to investigate the structure-affinity relationship of β-lactoglobulin binding, and the effect of this interaction on antioxidant activity. Based on a fluorescence quenching method, an improved mathematical model was adopted to calculate the binding constants, with a correction for the inner-filter effect. Hydroxylation at the 3-position increased the affinity of the phenolic acids for β-lactoglobulin, while hydroxylation at the 2- or 4-positions had a negative effect. Complete methylation of all hydroxy groups, except at the 3-position, enhanced the binding affinity. Replacing the hydroxy groups with methyl groups at the 2-position also had a positive effect. Hydrogen bonding was one of the binding forces for the interaction. The antioxidant activity of phenolic acid-β-lactoglobulin complexes was higher than that of phenolic acids alone. These findings provide an understanding of the structure-activity relationship of the interaction between β-lactoglobulin and phenolic acids. Copyright © 2017 Elsevier Ltd. All rights reserved.