Showing papers by "University of Memphis published in 2009"

Prolonged Grief Disorder: Psychometric Validation of Criteria Proposed for DSM-V and ICD-11

Abstract: Background: Bereavement is a universal experience, and its association with excess morbidity and mortality is well established. Nevertheless, grief becomes a serious health concern for a relative few. For such individuals, intense grief persists, is distressing and disabling, and may meet criteria as a distinct mental disorder. At present, grief is not recognized as a mental disorder in the DSM-IV or ICD-10. The goal of this study was to determine the psychometric validity of criteria for prolonged grief disorder (PGD) to enhance the detection and potential treatment of bereaved individuals at heightened risk of persistent distress and dysfunction. Methods and Findings: A total of 291 bereaved respondents were interviewed three times, grouped as 0–6, 6–12, and 12– 24 mo post-loss. Item response theory (IRT) analyses derived the most informative, unbiased PGD symptoms. Combinatoric analyses identified the most sensitive and specific PGD algorithm that was then tested to evaluate its psychometric validity. Criteria require reactions to a significant loss that involve the experience of yearning (e.g., physical or emotional suffering as a result of the desired, but unfulfilled, reunion with the deceased) and at least five of the following nine symptoms experienced at least daily or to a disabling degree: feeling emotionally numb, stunned, or that life is meaningless; experiencing mistrust; bitterness over the loss; difficulty accepting the loss; identity confusion; avoidance of the reality of the loss; or difficulty moving on with life. Symptoms must be present at sufficiently high levels at least six mo from the death and be associated with functional impairment. Conclusions: The criteria set for PGD appear able to identify bereaved persons at heightened risk for enduring distress and dysfunction. The results support the psychometric validity of the criteria for PGD that we propose for inclusion in DSM-V and ICD-11. Please see later in the article for the Editors’ Summary.

Acute exercise and oxidative stress: a 30 year history.

Abstract: The topic of exercise-induced oxidative stress has received considerable attention in recent years, with close to 300 original investigations published since the early work of Dillard and colleagues in 1978. Single bouts of aerobic and anaerobic exercise can induce an acute state of oxidative stress. This is indicated by an increased presence of oxidized molecules in a variety of tissues. Exercise mode, intensity, and duration, as well as the subject population tested, all can impact the extent of oxidation. Moreover, the use of antioxidant supplements can impact the findings. Although a single bout of exercise often leads to an acute oxidative stress, in accordance with the principle of hormesis, such an increase appears necessary to allow for an up-regulation in endogenous antioxidant defenses. This review presents a comprehensive summary of original investigations focused on exercise-induced oxidative stress. This should provide the reader with a well-documented account of the research done within this area of science over the past 30 years.

Predicting Reading Comprehension in Early Elementary School: The Independent Contributions of Oral Language and Decoding Skills

Abstract: The authors examined the development of oral language and decoding skills from preschool to early elementary school and their relation to beginning reading comprehension using a cross-sequential design. Four- and 6-year-old children were tested on oral language and decoding skills and were retested 2 years later. In all age groups, oral language and decoding skills formed distinct clusters. The 2 clusters were related to each other in preschool, but this relation became weaker in kindergarten and 2nd grade. Structural equation modeling showed that both sets of skills in 2nd grade independently predicted a child's reading comprehension. These findings confirm and extend the view that the 2 clusters of skills develop early in a child's life and contribute to reading comprehension activities in early elementary school, with each cluster making a considerable, unique contribution

Chapter 9 Toward a Comprehensive Model of Comprehension

Abstract: The goal of this chapter is to provide the foundation toward developing a more comprehensive model of reading comprehension. To this end, seven prominent comprehension models (Construction–Integration, Structure-Building, Resonance, Event-Indexing, Causal Network, Constructionist, and Landscape) are described, evaluated, and compared. We describe what comprehension models have offered thus far, differences and similarities between them, and what comprehension processes are not included within any of the models, and thus, what should be included in a comprehensive model. Our primary conclusion from the review of this literature is that current models of comprehension are not necessarily contradictory, but rather cover different spectrums of comprehension processes. Further, no one model adequately accounts for a wide variety of reading situations that have been observed and the range of comprehension considered thus far in comprehension models is too limited.

Theoretical, conceptual, methodological, and instructional issues in research on metacognition and self-regulated learning: A discussion

Abstract: Learning typically involves the use of numerous self-regulatory processes such as planning, knowledge activation, metacognitive monitoring and regulation, and reflection (Azevedo 2009; Azevedo and Hadwin 2005; Graesser et al. 2005; Schraw 2006; Veenman et al. 2006; Zimmerman 2008). According to Pintrich (2000), self-regulated learning (SRL) is an active, constructive process whereby students set goals for their learning and then attempt to monitor, regulate, and control their cognition, motivation, and behavior guided and constrained by their goals and the contextual features in the environment. Most models of SRL propose a general time-ordered sequence that students follow as they perform a task, but there is no strong assumption that the various phases (such as planning, monitoring, control) are hierarchically or linearly structured such that earlier phases must occur before later phases (see Ainley and Patrick 2006; Azevedo and Witherspoon 2009; Boekaerts et al. 2000; Butler and Winne 1995; Efklides 2008; Flavell 1979; Greene and Azevedo 2007; Hacker et al. 1998, 2007; Pintrich 2000; Schraw 2006; Schraw and Moshman 1995; Schunk 2001, 2005; Winne 2001; Winne and Hadwin 1998, 2008; Zimmerman 1989, 2001, 2006, 2008; Zimmerman and Schunk 2001). As an example, imagine a student using a computer simulation to learn about the cardiovascular system. One could imagine this self-regulated learner would analyze the learning situation, set meaningful goals, and determine which strategies to use given the task conditions. In addition, the student may generate motivational beliefs based on prior experience with the topic, ability to use a non-traditional computerized environment, Metacognition Learning (2009) 4:87–95 DOI 10.1007/s11409-009-9035-7

Role of Platelets in Atherothrombosis

Abstract: Platelets play a pivotal role in atherothrombosis and therefore are primary targets of antithrombotic therapy. They release an array of agonists, such as adenosine diphosphate (ADP); adhesive molecules, such as P-selectin, thrombospondin, fibrinogen, and von Willebrand factor; coagulation factors; and growth factors. In turn, they present transmembrane receptors for a plethora of agonists and ligands. Heterodimeric glycoproteins of the integrin family bind extracellular matrix and plasma proteins; mediate adhesion, activation, spreading, and aggregation; and facilitate intercellular bidirectional signal transduction. Glycoprotein IIb/IIIa is the most abundant platelet integrin and membrane surface glycoprotein. Glycolipids, heparins, proteoglycans, tetraspanins, and a multitude of other molecules, such as tumor necrosis factor–α, CD40L, growth arrest–specific 6, Eph receptor tyrosine kinases, and signaling lymphocytic activation molecule receptors, have been implicated in atherothrombosis. ADP promotes platelet aggregation by binding to platelet surface receptors P2Y 1 and P2Y 12 ; the thienopyridines inhibit aggregation by binding covalently to P2Y 12 . Thrombin, a potent initiator of platelet aggregation, activates platelets by cleaving protease-activated receptors (PARs) PAR-1 and PAR-4 and further propagates its effect by activating nearby platelets. A number of pharmacologic agents with antiplatelet actions have been developed, but the search continues for agents that strike an optimal balance between control of thrombosis and serious bleeding.

Conversation and Coordinative Structures

Abstract: People coordinate body postures and gaze patterns during conversation. We review literature showing that (1) action embodies cognition, (2) postural coordination emerges spontaneously when two people converse, (3) gaze patterns influence postural coordination, (4) gaze coordination is a function of common ground knowledge and visual information that conversants believe they share, and (5) gaze coordination is causally related to mutual understanding. We then consider how coordination, generally, can be understood as temporarily coupled neuromuscular components that function as a collective unit known as a coordinative structure in the motor control literature. We speculate that the coordination of gaze and body sway found in conversation may be understood as a cross-person coordinative structure that embodies the goals of the joint action system.

Quality control criteria for solid-contact, solvent polymeric membrane ion-selective electrodes

Abstract: After a long history and conflicting views, solid-contact (SC) solvent polymeric membrane ion-selective electrodes (ISEs) emerged as reliable potentometric-sensing devices with unique advantages. From the large variety of proposed SCs inherently conductive polymers emerged as the materials of choice. In our view, the most attractive feature of SC ISEs is their compatibility with thin- and thick-film microfabrication technologies that can provide cheap, mass-produced sensors and sensor arrays that can be integrated with the measuring, data acquisition, and control electronics in a straightforward way. However, despite the impressive properties of certain SC electrodes and their potential advantages, they remained primarily in the research laboratories. To make the jump from the research laboratories into commercial devices, it would be essential to prove that miniaturized SC ISEs can indeed match or surpass the performance characteristics of the conventional, liquid-contact macroelectrodes. In addition, it would be important to settle on the quality control criteria and testing protocols for assessing the performance characteristics of SC electrodes. It could help in interpreting the sometimes-inconsistent experimental data. Once cheap, miniaturized, SC ISEs will mach the performance characteristics of macroscopic-size electrodes, it is expected to have an important impact in a variety of applications requiring robust, maintenance-free, or single-use ISEs, e.g., in homecare or bedside diagnostics, environmental analysis, and quality control assessment. In addition, reliable SC ISEs are expected to revitalize the field of ion-selective field effect transistors and open new possibilities in combination with nanowire-based devices.

Marriage amendments and psychological distress in lesbian, gay, and bisexual (LGB) adults.

Abstract: An online survey of lesbian, gay, and bisexual (LGB) adults (N = 1,552) examined minority stress (I. H. Meyer, 2003) and psychological distress following the 2006 general election in which constitutional amendments to limit marriage to 1 man and 1 woman were on the ballot in 9 states. Following the November election, participants living in states that passed a marriage amendment reported significantly more minority stress (i.e., exposure to negative media messages and negative conversations, negative amendment-related affect, and LGB activism) and higher levels of psychological distress (negative affect, stress, and depressive symptoms) than participants living in the other states. Multiple hierarchical regression analyses revealed significant positive main effects of minority stress factors and state ballot status on psychological distress. In addition, the association between amendment-related affect and psychological distress was significantly higher in states that had passed a marriage amendment compared with other states. Discussion of these findings emphasizes that marriage amendments create an environment associated with negative psychological outcomes for LGB individuals.

Genetic versus chemoprotective activation of Nrf2 signaling: overlapping yet distinct gene expression profiles between Keap1 knockout and triterpenoid-treated mice

Abstract: Loss of NF-E2-related factor 2 (Nrf2) signaling increases susceptibility to acute toxicity, inflammation and carcinogenesis in mice due to the inability to mount adaptive responses. In contrast, disruption of Keap1 (a cytoplasmic modifier of Nrf2 turnover) protects against these stresses in mice, although inactivating mutations in Keap1 have been identified recently in some human cancers. Global characterization of Nrf2 activation is important to exploit this pathway for chemoprevention in healthy, yet at-risk individuals and also to elucidate the consequences of hijacking the pathway in Keap1-mutant human cancers. Liver-targeted conditional Keap1-null, Albumin-Cre:Keap1(flox/−) (CKO) mice provide a model of genetic activation of Nrf2 signaling. By coupling global gene expression analysis of CKO mice with analysis of pharmacologic activation using the synthetic oleanane triterpenoid 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im), we are able to gain insight into pathways affected by Nrf2 activation. CDDO-Im is an extremely potent activator of Nrf2 signaling. CKO mice were used to identify genes modulated by genetic activation of Nrf2 signaling. The CKO response was compared with hepatic global gene expression changes in wild-type mice treated with CDDO-Im at a maximal Nrf2 activating dose. The results show that genetic and pharmacologic activation of Nrf2 signaling modulates pathways beyond detoxication and cytoprotection, with the largest cluster of genes associated with lipid metabolism. Genetic activation of Nrf2 results in much larger numbers of detoxication and lipid metabolism gene changes. Additionally, analysis of pharmacologic activation suggests that Nrf2 is the primary mediator of CDDO-Im activity, though other cell-signaling targets are also modulated following an oral dose of 30 μmol/kg.

Reliability and validity of a demand curve measure of alcohol reinforcement.

Abstract: Recent clinical research suggests that several self-report behavioral economic measures of relative reinforcing efficacy (RRE) may show utility as indices of substance abuse problem severity. The goal of the present study was to evaluate the reliability and validity of the Alcohol Purchase Task (APT), a RRE measure that uses hypothetical choices regarding alcohol purchases at varying prices (demand curves) to generate several indices of alcohol-related reinforcement. Participants were 38 college students who reported recent alcohol consumption. Both the raw alcohol purchase/consumption values and several of the computed reinforcement parameters (intensity & Omax) showed good to excellent 2-week test-retest reliability. Reinforcement parameters derived from both a linear-elasticity (Hursh, Raslear, Bauman, & Black, 1989) and an exponential (Hursh & Silberberg, 2008) demand curve equation were generally less reliable, despite the fact that both equations provided a good fit to participants' reported consumption data. The APT measures of demand intensity (number of drinks consumed when price = 0), Omax (maximum expenditure), and elasticity (alpha) were correlated with weekly drinking, alcohol-related problems, and other self-report RRE measures (relative discretionary monetary expenditures toward alcohol and/or relative substance-related activity participation and enjoyment). Demand intensity was uniquely associated with problem drinking in a regression model that controlled for weekly consumption. These results provide support for the reliability and validity of the RRE indices generated with the APT.

Strategies for online communities

Abstract: This study examines the participation of firms in online communities as a means to enhance demand for their products. We begin with theoretical arguments and then develop a simulation model to illustrate how demand evolves as a function of interpersonal communication and a firm's chosen strategy. In this model, the firm's strategy involves allocating advocates who promote its product in online communities. Our model results point to some key parameters informing firms' strategies when social learning processes shape demand. Copyright © 2008 John Wiley & Sons, Ltd.

The Role of Teachers' Psychological Experiences and Perceptions of Curriculum Supports on the Implementation of a Social and Emotional Learning Curriculum

Abstract: . The present study examined how teachers' psychological experiences of burnout and efficacy as well as perceptions of curriculum supports (e.g., coaching) were associated with their implementation dosage and quality of Promoting Alternative Thinking Strategies, a social-emotional curriculum. Results revealed that teachers' psychological experiences and perceptions of curriculum supports were associated with implementation. Teacher burnout was negatively associated and efficacy was positively associated with implementation dosage. Teachers who perceived their school administration as more supportive reported higher implementation quality, and positive perceptions of training and coaching were associated with higher levels of implementation dosage and quality. Teachers who reported the highest levels of burnout and the most negative perceptions of curriculum supports reported the lowest levels of implementation dosage and quality. The findings suggest that both individual and organizational factors are related to self-reported implementation and may be important to address in order to maximize the effectiveness of school-based curricula. ********** The role of teachers has changed and expanded over the past few decades. As a result, teachers' rates of stress and burnout are believed to have increased, particularly in urban schools, and in turn may be influencing teachers' effectiveness (Jennings & Greenberg, 2009). When asked to implement new curricula, it is likely that teachers who have these psychological experiences in the workplace, and who perceive low levels of support for the innovation, will be the most vulnerable to poor implementation quality. Guided by an ecological systems framework (Bronfenbrenner, 1986) and recent conceptualization of individual and organizational factors that influence school-based implementation efforts (Greenberg, Domitrovich, Graczyk, & Zins, 2004), the present study examined how teachers' psychological experiences of burnout and efficacy as well as their perceptions of curriculum supports (e.g., school administration, training, and coaching) were associated with teachers' self-reported implementation of an evidence-based, social-emotional curriculum. The Changing Roles and Conditions for American Teachers Teachers' roles have evolved with new demands that result, in part, from federal legislation. Most recently, the No Child Left Behind (NCLB) Act (2001) has placed additional pressures and accountability on teachers and schools. For instance, teachers must ensure that all students make adequate progress in core academic areas. Under NCLB, districts that fail to make adequate yearly progress for multiple consecutive years become subject to increasingly serious consequences and interventions (No Child Left Behind Act, 2001). Although many occupations require their employees to demonstrate ongoing competence in their roles and adapt to new job requirements, the recent changes for teachers are without precedent. Given the fact that students' performance is determined by a variety of factors that lie outside of teachers' control, the pressure regarding student performance can cause a high degree of stress (Huberman, 2005). Even prior to NCLB, heightened expectations, broader demands, and the implementation of multiple reforms had already led to significant job intensification in teachers' work lives (Hargreaves, 1994). In the current economy, teachers are pressed to do more work with fewer resources, and many face persistent and chronic overload (Vandenberghe & Huberman, 1999). In the most recent report of the nationally representative School and Staffing Survey (2003-2004), public school teachers reported that they were contracted to work 37.7 hr per week, but when they were asked to also take into account time spent on school-related work outside of the school day, teachers reported actually working an average of 52.8 hr per week (Strizek, Pittsonberger, Riordan, Lyter, & Orlofsky, 2006). …

First decade of Organizational Research Methods: Trends in design, measurement, and data-analysis topics.

Abstract: The authors conducted a content analysis of the 193 articles published in the first 10 volumes (1998 to 2007) of Organizational Research Methods (ORM). The most popular quantitative topics are surv...

Epidemiology of Incident Heart Failure in a Contemporary Elderly Cohort : The Health, Aging, and Body Composition Study

Abstract: Background The race- and sex-specific epidemiology of incident heart failure (HF) among a contemporary elderly cohort are not well described. Methods We studied 2934 participants without HF enrolled in the Health, Aging, and Body Composition Study (mean [SD] age, 73.6 [2.9] years; 47.9% men; 58.6% white; and 41.4% black) and assessed the incidence of HF, population-attributable risk (PAR) of independent risk factors for HF, and outcomes of incident HF. Results During a median follow-up of 7.1 years, 258 participants (8.8%) developed HF (13.6 cases per 1000 person-years; 95% confidence interval, 12.1-15.4). Men and black participants were more likely to develop HF. No significant sex-based differences were observed in risk factors. Coronary heart disease (PAR, 23.9% for white participants and 29.5% for black participants) and uncontrolled blood pressure (PAR, 21.3% for white participants and 30.1% for black participants) carried the highest PAR in both races. Among black participants, 6 of 8 risk factors assessed (smoking, increased heart rate, coronary heart disease, left ventricular hypertrophy, uncontrolled blood pressure, and reduced glomerular filtration rate) had more than 5% higher PAR compared with that among white participants, leading to a higher overall proportion of HF attributable to modifiable risk factors in black participants vs white participants (67.8% vs 48.9%). Participants who developed HF had higher annual mortality (18.0% vs 2.7%). No racial difference in survival after HF was noted; however, rehospitalization rates were higher among black participants (62.1 vs 30.3 hospitalizations per 100 person-years, P Conclusions Incident HF is common in older persons; a large proportion of HF risk is attributed to modifiable risk factors. Racial differences in risk factors for HF and in hospitalization rates after HF need to be considered in prevention and treatment efforts.

Dual Activity Lysophosphatidic Acid Receptor Pan-Antagonist/Autotaxin Inhibitor Reduces Breast Cancer Cell Migration In vitro and Causes Tumor Regression In vivo

Abstract: Signal transduction modifiers that modulate the lysophosphatidic acid (LPA) pathway have potential as anticancer agents. Herein, we describe metabolically stabilized LPA analogues that reduce cell migration and invasion and cause regression of orthotopic breast tumors in vivo. Two diastereoisomeric alpha-bromophosphonates (BrP-LPA) were synthesized, and the pharmacology was determined for five LPA G protein-coupled receptors (GPCRs). The syn and anti diastereomers of BrP-LPA are pan-LPA GPCR antagonists and are also nanomolar inhibitors of the lysophospholipase D activity of autotaxin, the dominant biosynthetic source of LPA. Computational models correctly predicted the diastereoselectivity of antagonism for three GPCR isoforms. The anti isomer of BrP-LPA was more effective than syn isomer in reducing migration of MDA-MB-231 cells, and the anti isomer was superior in reducing invasion of these cells. Finally, orthotopic breast cancer xenografts were established in nude mice by injection of MB-231 cells in an in situ cross-linkable extracellular matrix. After 2 weeks, mice were treated with the BrP-LPA alone (10 mg/kg), Taxol alone (10 mg/kg), or Taxol followed by BrP-LPA. All treatments significantly reduced tumor burden, and BrP-LPA was superior to Taxol in reducing blood vessel density in tumors. Moreover, both the anti- and syn-BrP-LPA significantly reduced tumors at 3 mg/kg.

Corruption, Political Connections, and Municipal Finance

Abstract: We show that state corruption and political connections have strong effects on municipal bond sales and underwriting. Higher state corruption is associated with greater credit risk and higher bond yields. Corrupt states can eliminate the corruption yield penalty by purchasing credit enhancements. Underwriting fees were significantly higher during an era when underwriters made political contributions to win underwriting business. This pay-to-play underwriting fee premium exists only for negotiated bid bonds where underwriting business can be allocated on the basis of political favoritism. Overall, our results show a strong impact of corruption and political connections on financial market outcomes. The Author 2009. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org, Oxford University Press.

Design and characterization of a novel chitosan/nanocrystalline calcium phosphate composite scaffold for bone regeneration

Abstract: To meet the challenge of regenerating bone lost to disease or trauma, biodegradable scaffolds are being investigated as a way to regenerate bone without the need for an auto- or allograft. Here, we have developed a novel microsphere-based chitosan/nanocrystalline calcium phosphate (CaP) composite scaffold and investigated its potential compared to plain chitosan scaffolds to be used as a bone graft substitute. Composite and chitosan scaffolds were prepared by fusing microspheres of 500-900 microm in diameter, and porosity, degradation, compressive strength, and cell growth were examined. Both scaffolds had porosities of 33-35% and pore sizes between 100 and 800 . However, composite scaffolds were much rougher and, as a result, had 20 times more surface area/unit mass than chitosan scaffolds. The compressive modulus of hydrated composite scaffolds was significantly higher than chitosan scaffolds (9.29 +/- 0.8 MPa vs. 3.26 +/- 2.5 MPa), and composite scaffolds were tougher and more flexible than what has been reported for other chitosan-CaP composites or CaP scaffolds alone. Using X-ray diffraction, scaffolds were shown to contain partially crystalline hydroxyapatite with a crystallinity of 16.7% +/- 6.8% and crystallite size of 128 +/- 55 nm. Fibronection adsorption was increased on composite scaffolds, and cell attachment was higher on composite scaffolds after 30 min, although attachment rates were similar after 1 h. Osteoblast proliferation (based on dsDNA measurements) was significantly increased after 1 week of culture. These studies have demonstrated that composite scaffolds have mechanical properties and porosity sufficient to support ingrowth of new bone tissue, and cell attachment and proliferation data indicate composite scaffolds are promising for bone regeneration.

Latent structure of facets of alcohol reinforcement from a behavioral economic demand curve

Abstract: Rationale Behavioral economic demand curves are quantitative representations of the relationship between consumption of a drug and its cost. Demand curves provide a multidimensional assessment of reinforcement, but the relationships among the various indices of reinforcement have been largely unstudied.