76 results on '"Powers TA"'
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2. New algorithm is designed to take the annoyance out of transient noise.
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Chalupper J and Powers TA
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- 2007
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3. Wireless technology designed to provide true binaural amplification.
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Powers TA and Burton P
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- 2005
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4. Three-microphone instrument is designed to extend benefits of directionality.
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Powers TA and Hamacher V
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- 2002
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5. Consideration of auditory acclimatization in the prescriptive fitting of hearing aids.
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Mueller HG and Powers TA
- Published
- 2001
6. Study finds real-world benefit from digital noise reduction.
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Powers TA, Branda E, Hernandez A, and Pool A
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- 2006
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7. Combined Computerized Tomography and Angiography in Evaluation of Hemorrhage Into Pancreatic Pseudocysts
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Powers Ta, O'Leary Jp, Bean D, and Bluett Mk
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Male ,medicine.medical_specialty ,Pancreatic disease ,Pancreatic pseudocyst ,Diagnosis, Differential ,Aneurysm ,Pancreatic Pseudocyst ,medicine ,Humans ,Aged ,medicine.diagnostic_test ,business.industry ,Angiography ,General Medicine ,medicine.disease ,Mesenteric Arteries ,Pancreatitis ,Radiology ,Pancreatic Cyst ,Differential diagnosis ,Gastrointestinal Hemorrhage ,Tomography, X-Ray Computed ,Complication ,business ,Perfusion - Abstract
Hemorrhage into a pancreatic pseudocyst is a rare but frequently lethal complication of pancreatitis, which remains a diagnostic and therapeutic challenge. Angiography alone or in combination with ultrasonography and radionuclide perfusion scans will occasionally fail to identify adequately the source of bleeding. We have presented a case illustrating the superiority of dynamic computerized tomography and angiography in the preoperative evaluation of a patient with pancreatic disease and upper gastrointestinal hemorrhage.
- Published
- 1987
8. Echogenic hepatic abscess without radiographic evidence of gas
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Powers, TA, primary, Jones, TB, additional, and Karl, JH, additional
- Published
- 1981
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9. Hepatic abscesses can be echogenic with or without demonstrable gas
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Jones, TB, primary and Powers, TA, additional
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- 1983
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10. Self-control and grit: associations with weight management and healthy habits.
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Gorin AA, Leahey TM, Cornelius T, Bourgea K, and Powers TA
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- Female, Humans, Male, Exercise, Habits, Weight Loss, Health Behavior, Self-Control
- Abstract
Weight management requires resisting immediate temptations in one's environment (self-control) as well as the ability to persevere towards one's long-term goals despite minor setbacks (grit). This study sought to establish relationships between self-control, grit, and behavioral and health outcomes in the context of a couples-based weight management intervention. Couples (n = 64 dyads) in a behaviorally based intervention completed measures of self-control and grit at study entry and the end of treatment (6 months). Habit automaticity for self-weighing and exercise as well as objective weights were measured at baseline, 6 months, and 12 months (maintenance). Self-control and grit increased during treatment; these increases were significantly associated with greater self-weighing habit automaticity at 6 months. Baseline self-control, changes in self-control, and baseline grit were also associated with 6-month exercise automaticity. Only baseline grit was associated with weight loss maintenance. No partner effects were observed. Findings suggest that self-control and grit are malleable constructs that may play an important role in health behavior habits associated with weight management.ClinicalTrials.gov: NCT02570009, October, 7, 2015., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2024
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11. MarkeTrak and EuroTrak: What We Can Learn by Looking Beyond the U.S. Market.
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Powers TA and Bisgaard N
- Abstract
The MarkeTrak survey of the trends in hearing aid use, satisfaction and adoption in the United States has been conducted since 1989 by the Hearing Industries Association. It provide the hearing aid industry with valuable about the consumers view of the products and services within the industry. The EuroTrak survey is conducted by the European Hearing Instrument Manufactures Association. It is the counterpart to MarkeTrak and provides similar data for over a dozen countries in Europe, and Asia. While there are differences in the distribution models and reimbursement methods for these counties, many of the key metrics concerning hearing aid use and satisfaction can be compared., Competing Interests: Conflict of Interest None declared., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)
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- 2022
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12. Evidence of the Associations between Individual and Partner Autonomy Support and Physiological Stress in the Context of Conversations about Weight among Couples Who are Overweight or Obese during a 6-Month Intervention.
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Denes A, Crowley JP, Ponivas ALP, Cornelius T, Allred RJ, Gettens KM, Powers TA, and Gorin AA
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- Communication, Humans, Obesity, Saliva, Stress, Physiological, Stress, Psychological psychology, Hydrocortisone, Overweight
- Abstract
The aim of the study was to examine the impact of supportive communication on acute physiological stress responses during weight-related conversations taking place throughout a couples' weight loss program. Participants were 47 married or cohabitating couples where each partner had a BMI of 25-40 kg/m
2 . Couples were randomized as a dyad into a traditional weight loss program or a program that also included training in providing support to one's partner throughout the weight loss process. Structured conversations between partners about weight management were videotaped at baseline and 6 months. Participants provided saliva samples before and after the conversations, which were assayed for cortisol and salivary alpha-amylase (sAA) to determine physiological stress and anxiety responses to conversations about weight. The results indicated that receiving support from one's partner when discussing weight-related issues was associated with greater physiological stress, as indicated by higher cortisol and sAA levels, whereas providing support to one's partner was associated with lower cortisol levels and higher sAA levels. The findings suggest that receiving support is not a universally positive experience, especially for populations facing health issues. The mixed findings for support provision align with previous studies identifying a negative association between affectionate communication and cortisol levels, as well as a positive association between sAA and anxiety and emotional arousal. The findings and their implications for understanding the physiological correlates of couples' conversations about weight are discussed.- Published
- 2022
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13. Autonomy support in a couples weight loss trial: Helping yourself while helping others.
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Powers TA, Koestner R, Denes A, Cornelius T, and Gorin AA
- Subjects
- Humans, Male, Personal Satisfaction, Personal Autonomy, Weight Loss
- Abstract
Introduction: Self-determination theory proposes that autonomy-supportive environments produce better health outcomes, and evidence demonstrating the importance of autonomy support for health behavior change has become increasingly clear. The bulk of the previous research has focused on the effects of receiving autonomy support, whereas the present study focuses on the potential impact of providing autonomy support for improving the weight loss and relationship satisfaction of the support provider., Method: Sixty-four couples were randomized to a standard weight loss intervention or to an intervention that included training to enhance autonomy support behavior (e.g., empathic responding, accepting personal choices, etc.). Groups met weekly for 6 months, with assessments at baseline, 3, 6, and 12 months. The assessment of provided autonomy support was based on ratings of videotaped interactions of the couple discussing weight loss issues and on partner report of the autonomy support they received., Results: The results did not show any condition effects; however, the results for both conditions indicated that beyond receiving autonomy support, providing autonomy support was associated with greater sustained weight loss for the support provider, and for men greater relationship satisfaction over time., Discussion: The results confirm the importance of couples-based interventions and autonomy support for behavior change. In addition, it appears that providing autonomy support is useful for both the recipient and the provider. These results point to the need for developing targeted interventions to facilitate the provision of autonomy support. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
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- 2022
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14. Autonomous motivation and support flourishes for individuals higher in collaborative personality factors: Agreeableness, assisted autonomy striving, and secure attachment.
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Levine SL, Milyavskaya M, Powers TA, Holding AC, and Koestner R
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- Achievement, Humans, Personality, Personality Disorders, Motivation, Personal Autonomy
- Abstract
Introduction: Individuals who strive autonomously for their goals, and who perceive autonomy supportive environments are more successful during goal pursuit. What dispositional factors predict autonomy flourishing during goal pursuit?, Methods: Four longitudinal studies were conducted over an 8-month academic year, and university students (N
total = 1,544) completed surveys on motivation, support, and personality. Structural equation models were created using Mplus software to test whether collaborative personality factors were related to growth in autonomous motivation and autonomy support., Results: All three distinct collaborative personality factors, trait Agreeableness, assisted autonomy striving, and secure parental attachment, were related to increases in autonomous motivation over the academic year. Conscientiousness, assisted autonomy, and secure attachment were related to increases in perceived autonomy support. A higher order latent collaborative traits factor, composed of Agreeableness, assisted autonomy, and secure attachment was found to be related to increased autonomous motivation and support over the academic year and resulted in increased goal progress., Conclusion: These results suggest that individuals higher in collaborative personality factors experience growth in personal autonomy during goal pursuit. Future research is needed to determine how to promote collaboration in goal pursuit to further help individuals successfully strive for their goals., (© 2021 Wiley Periodicals LLC.)- Published
- 2021
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15. The role of goal-related autonomy: A self-determination theory analysis of perfectionism, poor goal progress, and depressive symptoms.
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Moore E, Holding AC, Moore A, Levine SL, Powers TA, Zuroff DC, and Koestner R
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- Adolescent, Adult, Depression diagnosis, Female, Follow-Up Studies, Humans, Longitudinal Studies, Male, Middle Aged, Young Adult, Depression psychology, Depression therapy, Goals, Motivation physiology, Perfectionism, Personal Autonomy
- Abstract
Adopting a self-determination theory perspective, this 3-wave longitudinal study explores the role of perfectionism in goal pursuit and the experience of depressive symptoms. The findings highlight the role of goal-related autonomy in mediating the opposite effects of self-critical and personal standards perfectionism on goal progress and depressive symptoms over the course of an academic year. The results suggest a way of understanding the pathway to depressive symptoms and poor goal progress in perfectionists. They point to a number of implications for clinical practice when working with self-critical perfectionists. Specifically, they indicate that interventions aimed at promoting autonomous motivation, may not only bolster goal progress but also act as a protective factor against depressive symptoms. Together, the results indicate that autonomous motivation is central to goal progress and suggest that low goal-related autonomy can be linked to negative outcomes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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- 2021
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16. MarkeTrak 10: History and Methodology.
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Powers TA and Rogin C
- Abstract
MarkeTrak has been conducted on a regular schedule for over 30 years to take the pulse of the hearing health care market and of consumers with hearing loss. The current version, MarkeTrak 10 (MT10), builds on the successful completion of MarkeTrak 9, with the same two objectives: to estimate hearing difficulty, hearing aid usage, and adoption of hearing aids in the United States and to gain insights into the consumer's journey through the hearing health care delivery system. In addition, MarkeTrak 10 added additional questions regarding use and satisfaction with Personal Sound Amplification Products (PSAPs) by both owners and nonowners of hearing aids., (© Thieme Medical Publishers.)
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- 2020
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17. A randomized controlled trial of a theory-based weight-loss program for couples.
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Gorin AA, Powers TA, Gettens K, Cornelius T, Koestner R, Mobley AR, Pescatello LS, and Huedo-Medina TB
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- Adolescent, Adult, Aged, Female, Humans, Male, Middle Aged, Social Support, Spouses psychology, Young Adult, Weight Reduction Programs methods
- Abstract
Objective: Weight gain occurs during marriage, yet obesity treatment is focused on individuals. Outcomes may be improved by targeting joint weight loss and the interpersonal milieu that fosters spousal interdependence. Self-determination theory (SDT) posits that autonomy-supportive environments (e.g., promote meaningful choice, minimize control) produce better health outcomes. This trial tested an SDT-informed weight-loss intervention intended to facilitate autonomy support in couples., Method: Sixty-four couples were randomized to standard behavioral weight loss (BWL) that couples attended together or to a SDT-informed weight-loss intervention (SDT-WL) that aimed to bolster autonomy support (AS). Groups met weekly for 6 months with assessments at 0, 3, 6, and 12 months., Results: Percent weight loss at 6 and 12 months was 10.4% ± 6.5% and 9.2% ± 8.2%. No differences were observed between the BWL and SDT-WL conditions in percent weight loss or changes in AS. Across conditions, higher baseline AS predicted greater weight loss at 6 and 12 months (ps <.001). Increases in AS over time predicted greater weight loss at 6 and 12 months (ps ≤ .02). Post hoc moderation analysis indicated that only participants with low (but not high) baseline AS achieved greater gains in AS at 12 months in SDT-WL than in the BWL conditions (p < .02)., Conclusions: Although no differences were found between conditions on weight loss or changes in autonomy support behavior, autonomy support from one's spouse predicted weight loss in both couples-based weight-loss approaches. For couples with low levels of AS, an SDT-informed approach was effective at increasing this desirable interpersonal behavior. (PsycINFO Database Record (c) 2020 APA, all rights reserved).
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- 2020
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18. Searching for the Source of the Leak: PIE and the Macklin Effect.
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Russell DW, Watts JR Jr, and Powers TA
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- Female, Humans, Lung Diseases, Interstitial therapy, Mediastinal Emphysema therapy, Pulmonary Emphysema therapy, Tomography, X-Ray Computed, Young Adult, Lung Diseases, Interstitial diagnostic imaging, Lung Diseases, Interstitial etiology, Mediastinal Emphysema diagnostic imaging, Mediastinal Emphysema etiology, Pulmonary Emphysema diagnostic imaging, Pulmonary Emphysema etiology
- Published
- 2018
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19. The role of partner autonomy support in motivation, well-being, and weight loss among women with higher baseline BMI.
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Gettens KM, Carbonneau N, Koestner R, Powers TA, and Gorin AA
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- Adult, Aged, Body Mass Index, Cross-Sectional Studies, Female, Humans, Male, Middle Aged, Quebec, Surveys and Questionnaires, Feeding Behavior psychology, Motivation, Personal Autonomy, Weight Loss
- Abstract
Introduction: The association of partner autonomy support with women's motivation for healthy eating, weight-related health behavior change, and psychological well-being has been largely overlooked. Results of 2 studies showed that the positive association between autonomy support and a variety of motivational and psychological outcomes was especially pronounced for women with high body mass index (BMI) (+1 SD ) compared to low BMI (-1 SD )., Method: In Study 1, autonomy support was measured as male partners' report of their behavior in a cross-sectional design. In Study 2, autonomy support was measured as female participants' perceptions of their partners' behavior in a longitudinal home environment-based behavioral weight loss intervention., Results: Study 1 showed that autonomy support from partners was associated with greater self-determined motivation for healthy eating and self-reported well-being among women with higher BMI. Study 2 showed that changes in partner autonomy support over 18 months of a home-based weight loss intervention were associated with increases in motivation for treatment and greater weight loss, especially for women who had higher baseline BMI., Discussion: Both studies demonstrated that autonomy support was associated with adaptive functioning across weight status but that it was especially potent for women with higher BMI. This pattern of findings is explained in terms of the pressures women with higher BMI may feel about their weight-related behaviors. (PsycINFO Database Record, ((c) 2018 APA, all rights reserved).)
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- 2018
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20. Project TEAMS (Talking about Eating, Activity, and Mutual Support): a randomized controlled trial of a theory-based weight loss program for couples.
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Gorin AA, Powers TA, Gettens K, Cornelius T, Koestner R, Mobley AR, Pescatello L, and Medina TH
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- Adolescent, Adult, Aged, Behavior Therapy, Eating psychology, Exercise psychology, Female, Follow-Up Studies, Humans, Male, Middle Aged, Personal Autonomy, Psychological Theory, Social Support, Spouses statistics & numerical data, Treatment Outcome, Weight Loss, Young Adult, Communication, Interpersonal Relations, Obesity therapy, Spouses psychology, Weight Reduction Programs methods
- Abstract
Background: Obesity risk is shared between spouses, yet existing weight loss programs focus on individuals and not the marital dyad. Given the interdependence of weight in couples, weight management outcomes might be improved by targeting joint weight loss and the creation of an interpersonal milieu that supports long-term behavior change. According to Self-Determination Theory (SDT), greater autonomous self-regulation of behaviors, and subsequently better treatment outcomes, are observed in needs supportive environments in which personally meaningful choice is supported and criticism and control are minimized. Correlational analyses confirm these pathways in weight management, with needs support from one's spouse or partner emerging as a distinct predictor of weight loss success. Research is now needed to establish causal links and to develop and test weight loss interventions designed to facilitate the needs supportive behavior of spouses., Methods: Project TEAMS (Talking about Eating, Activity, and Mutual Support) is a randomized controlled trial testing a couples-based intervention, grounded in SDT, designed to change the social context of weight loss by training spouses to provide needs support for each other's eating and physical activity behavior. Sixty-four couples will be randomized to either 6 months of behavioral weight loss treatment informed by SDT (SDT-WL) or to 6 months of standard behavioral weight loss treatment (BWL). Couples will attend weekly sessions for 6 months and will be assessed at 0, 3, 6, and 12 months. By bolstering needs support, SDT-WL is predicted to increase autonomous self-regulation and perceived competence and produce greater weight loss and maintenance than standard behavioral treatment. Exploratory analyses will examine the SDT process model prediction that the influence of needs support on treatment outcomes will be mediated by autonomous self-regulation and perceived competence., Discussion: This study addresses the fundamental importance of interpersonal support in weight management by focusing on couples rather than individuals and using a rich theoretical framework to train spouses in supportive behaviors., Trial Registration: Clinicaltrials.gov ; NCT02570009 .
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- 2017
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21. Goal internalization and persistence as a function of autonomous and directive forms of goal support.
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Koestner R, Powers TA, Milyavskaya M, Carbonneau N, and Hope N
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- Adolescent, Adult, Female, Humans, Male, Prospective Studies, Young Adult, Goals, Personal Autonomy, Social Support
- Abstract
Two prospective studies examined the relations of autonomy support and directive support to goal internalization and goal persistence over a year. Study 1 examined the role of support and internalization in semester-long goals set by college students and whether the goals were reset in the following semester. Study 2 examined semester-long goals and long-term developmental goals. Study 1 showed that autonomy support was not only significantly associated with greater internalization and goal success in the fall semester, but it was also significantly associated with actually resetting and subsequently succeeding at goals that one had failed to reach. Study 2 showed that autonomy support was significantly associated with progress for short-term goals over the semester, whereas directive support was unrelated to progress. For long-term goals, autonomy support was significantly related to greater internalization of goals and to greater goal satisfaction, whereas directive support was significantly negatively related to these outcomes. These studies point to the beneficial effects of autonomy support on goal internalization and resilient persistence. The effects of directive support (null vs. negative) were moderated by the timeline of the goals., (© 2014 Wiley Periodicals, Inc.)
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- 2015
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22. Autonomy support, self-regulation, and weight loss.
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Gorin AA, Powers TA, Koestner R, Wing RR, and Raynor HA
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- Adult, Aged, Female, Follow-Up Studies, Humans, Male, Middle Aged, Program Evaluation, Young Adult, Personal Autonomy, Social Control, Informal, Social Support, Weight Loss, Weight Reduction Programs methods
- Abstract
Objective: Social support is believed to contribute to weight loss success, yet the type of support received is rarely assessed. To develop more effective weight loss interventions, examinations of the types of support that are associated with positive outcomes are needed. Self-Determination Theory suggests that support for an individual's autonomy is beneficial and facilitates internalization of autonomous self-regulation. We examined whether autonomy support and directive forms of support were associated with weight loss outcomes in a larger randomized controlled trial., Method: Adults (N = 201; 48.9 ± 10.5 years; 78.1% women) participating in a weight loss trial were assessed at 0, 6, and 18 months. Autonomy support (AS), directive support, and autonomous self-regulation (ASR) were measured at 0 and 6 months and examined in relation to 18-month weight loss outcomes., Results: Baseline AS and ASR did not predict outcomes; however, AS and ASR at 6 months positively predicted 18-month weight losses (ps < .05), encouragement of healthy eating at 6 months was negatively related to 18-month weight losses (p < .01), and other forms of directive support were not associated with outcomes., Conclusions: Autonomy support predicted better weight loss outcomes while some forms of directive support hindered progress. Weight loss trials are needed to determine whether family members and friends can be trained to provide autonomy support and whether this is more effective than programs targeting more general or directive forms of support.
- Published
- 2014
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23. Distinguishing autonomous and directive forms of goal support: their effects on goal progress, relationship quality, and subjective well-being.
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Koestner R, Powers TA, Carbonneau N, Milyavskaya M, and Chua SN
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- Achievement, Adolescent, Adult, Female, Friends, Humans, Male, Multilevel Analysis, Peer Group, Prospective Studies, Quality of Life, Social Support, Surveys and Questionnaires, Time Factors, Young Adult, Goals, Interpersonal Relations, Motivation, Personal Autonomy, Personal Satisfaction, Self Concept
- Abstract
Three studies examined the relations of autonomy support and directive support to goal progress over 3 months. Autonomy support was defined in terms of empathic perspective-taking, whereas directive support was defined in terms of the provision of positive guidance. Results from Study 1 revealed that autonomy support between romantic partners was significantly positively related to goal progress over 3 months, and that the beneficial effect of autonomy support was mediated by enhanced autonomous goal motivation. Study 2 involved female friend dyads and extended the goal progress results to include both self-reports and reports by peers. Study 3 showed that autonomy support similarly promoted progress at vicarious goals. Across three studies, autonomy support was also significantly associated with improved relationship quality and subjective well-being. Directive support was marginally associated with better goal progress across the three studies and unrelated to relationship quality or well-being.
- Published
- 2012
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24. The effects of self-criticism and self-oriented perfectionism on goal pursuit.
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Powers TA, Koestner R, Zuroff DC, Milyavskaya M, and Gorin AA
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- Adolescent, Adult, Female, Humans, Male, Quebec, Young Adult, Goals, Personality, Self-Assessment
- Abstract
Five separate studies examined the associations of self-criticism and self-oriented perfectionism with goal pursuit across a variety of domains. Although self-criticism has previously been shown to be related to diminished goal progress, a controversy remains regarding the potential association between aspects of "positive perfectionism," such as self-oriented perfectionism, and enhanced goal progress. The results of the five studies demonstrated a consistent pattern of negative association between self-criticism and goal progress. The results also showed a positive association between self-oriented perfectionism and goal progress when self-criticism was controlled. The important role of self-criticism for understanding the impact of perfectionistic concerns is highlighted by these results. Implications for the debate concerning the possible positive effects of perfectionistic strivings are also discussed., (© 2011 by the Society for Personality and Social Psychology, Inc)
- Published
- 2011
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25. Battery power comparison to charge medical devices in developing countries.
- Author
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Casanova AM, Bray AS, Powers TA, Nimunkar AJ, and Webster JG
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- Computer-Aided Design, Energy Transfer, Equipment Design, Equipment Failure Analysis, Reproducibility of Results, Sensitivity and Specificity, Developing Countries, Electric Power Supplies, Equipment and Supplies
- Abstract
Many people in developing countries cannot afford or rely on certain modes of electricity. We establish the reasonability of relying on lead-acid batteries, 9 V alkaline batteries, and lithium-ion batteries for charging low-voltage medical equipment. Based on the research and tests we conducted, we determined that using these battery types to charge medical devices truly is a reasonable solution.
- Published
- 2009
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26. Autonomous motivation, controlled motivation, and goal progress.
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Koestner R, Otis N, Powers TA, Pelletier L, and Gagnon H
- Subjects
- Achievement, Adolescent, Adult, Female, Humans, Intention, Male, Weight Loss, Young Adult, Goals, Individuality, Internal-External Control, Motivation, Problem Solving
- Abstract
Although the self-concordance of goals has been repeatedly shown to predict better goal progress, recent research suggests potential problems with aggregating autonomous and controlled motivations to form a summary index of self-concordance (Judge, Bono, Erez, & Locke, 2005). The purpose of the present investigation was to further examine the relations among autonomous motivation, controlled motivation, and goal progress to determine the relative importance of autonomous motivation and controlled motivation in the pursuit of personal goals. The results of three studies and a meta-analysis indicated that autonomous motivation was substantially related to goal progress whereas controlled motivation was not. Additionally, the relation of autonomous motivation to goal progress was shown to involve implementation planning. Together, the three studies highlight the importance for goal setters of having autonomous motivation and developing implementation plans, especially ones formulated in terms of approach strategies rather than avoidance strategies. The present research suggests that individuals pursuing goals should focus relatively greater attention on enhancing their autonomous motivation rather than reducing their controlled motivation.
- Published
- 2008
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27. Implementation intentions, perfectionism, and goal progress: perhaps the road to hell is paved with good intentions.
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Powers TA, Koestner R, and Topciu RA
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- Adolescent, Adult, Affect, Female, Humans, Male, Middle Aged, Self Efficacy, Goals, Intention, Motivation, Personality
- Abstract
Two studies explored whether perfectionism moderates the impact of implementation intentions on goal progress. Study 1 used an implementation intention manipulation to examine the effects of these plans in interaction with perfectionism on the progress of New Year's resolutions. Study 2 added a repeated implementation intention condition and monitored affect and monthly goal progress. The results of both studies revealed a significant backfire effect of the implementation intentions on goal progress for participants high on a particular dimension of perfectionism (socially prescribed perfectionism). These perfectionists reported doing significantly worse at reaching their personal goals when they were asked to formulate implementation intentions than when they completed a control exercise. There also was evidence that implementation planning aroused negative affect for socially prescribed perfectionists. These results are the first to suggest that implementation planning may be contra-indicated for individuals with self-critical tendencies.
- Published
- 2005
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28. Attaining personal goals: self-concordance plus implementation intentions equals success.
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Koestner R, Lekes N, Powers TA, and Chicoine E
- Subjects
- Adolescent, Adult, Female, Humans, Male, Achievement, Goals, Intention, Self Concept
- Abstract
The present article includes separate meta-analyses showing that self-concordance and implementation intentions are significantly positively associated with goal progress. Study 1 confirmed the positive relations of both self-concordance and implementation intentions to weekend goal progress. Study 2 confirmed the positive relation of self-concordance with monthly progress on New Year's resolutions but failed to find a direct benefit for implementation intentions. Both studies, however, obtained a significant interaction effect indicating that goal self-concordance and implementation intentions combined synergistically to facilitate goal progress. The article also reports a meta-analysis and results from the 2 studies that demonstrated that goal progress was associated with improved affect over time.
- Published
- 2002
29. Prospective comparison of radiologic, thoracoscopic, and pathologic staging in patients with early non-small cell lung cancer.
- Author
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Roberts JR, Blum MG, Arildsen R, Drinkwater DC Jr, Christian KR, Powers TA, and Merrill WH
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- Adult, Aged, Carcinoma, Non-Small-Cell Lung surgery, Female, Humans, Lung pathology, Lung Neoplasms surgery, Lymphatic Metastasis, Male, Middle Aged, Neoplasm Invasiveness, Neoplasm Staging, Pleural Effusion, Malignant pathology, Pleural Effusion, Malignant surgery, Precancerous Conditions surgery, Prognosis, Prospective Studies, Sensitivity and Specificity, Carcinoma, Non-Small-Cell Lung pathology, Lung Neoplasms pathology, Precancerous Conditions pathology, Thoracoscopy, Tomography, X-Ray Computed
- Abstract
Background: More accurate staging at the time of initial presentation could improve design of clinical trials and avoid inappropriate surgical decisions in individual patients. Preresection staging of patients with non-small cell lung cancer (NSCLC) is not straightforward, especially in patients with negative mediastinal nodes. The purpose of this study was to compare the results of radiologic, thoracoscopic, and pathologic staging in patients with NSCLC and negative mediastinoscopy., Methods: All patients with NSCLC underwent computed tomographic (CT) scanning before surgical staging with mediastinoscopy. Patients with negative mediastinoscopy then underwent thoracoscopic staging with examination of pleural surfaces, and identification of T (visceral and parietal pleural invasion, sampling of pleural fluid, and pleural lavage) and N (intraparenchymal and inferior mediastinal nodal sampling, if possible) stage descriptors before resection., Results: Thoracoscopy was more accurate than CT scanning in the staging of 50 patients with early lung cancer (stages IA, IB, IIA, and IIB), especially as regards T stage. Further, thoracoscopic examination ruled out malignant pleural effusions in 7 (14%) patients with radiologically obvious effusions, and identified radiologically silent malignant pleural effusions in 3 (6%) patients. Chest wall invasion was accurately identified at thoracoscopy in most patients. Finally, 3 patients with T1 lower lobe lesions and negative mediastinoscopy were found to have involvement of inferior mediastinal nodes (level 8 or 9) at thoracoscopy. However, thoracoscopy did not allow sampling of aortopulmonary window nodes in some patients with bulky left upper lobe lesions., Conclusions: Errors in thoracoscopic staging resulted in no inappropriate operations. However, errors in CT staging would have resulted in operations unlikely to help the patients, or would have inappropriately excluded patients from surgery. Thoracoscopic staging was more accurate than CT staging in this cohort of patients with NSCLC and negative mediastinoscopy.
- Published
- 1999
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30. Staging recurrent metastatic colorectal carcinoma with PET.
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Delbeke D, Vitola JV, Sandler MP, Arildsen RC, Powers TA, Wright JK Jr, Chapman WC, and Pinson CW
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- Algorithms, Female, Fluorodeoxyglucose F18, Humans, Male, Middle Aged, Neoplasm Staging, Portography methods, Sensitivity and Specificity, Tomography, X-Ray Computed, Adenocarcinoma diagnostic imaging, Adenocarcinoma secondary, Colorectal Neoplasms pathology, Deoxyglucose analogs & derivatives, Fluorine Radioisotopes, Liver Neoplasms diagnostic imaging, Liver Neoplasms secondary, Radiopharmaceuticals, Tomography, Emission-Computed
- Abstract
Unlabelled: Accurate detection of recurrent colorectal carcinoma remains a diagnostic challenge. The purposes of this study were to assess the accuracy of 18FDG-PET in patients with recurrent colorectal carcinoma in detecting liver metastases compared with computed tomography (CT) and CT portography, detecting extrahepatic metastases compared with CT and evaluating the impact on patient management., Methods: Fifty-two patients previously treated for colorectal carcinoma presented on 61 occasions with suspected recurrence and underwent 18FDG-PET of the entire body. PET, CT and CT portography images were analyzed visually. The final diagnosis was obtained by pathology (n = 44) or clinical and radiological follow-up (n = 17). The impact on management was reviewed retrospectively., Results: A total of 166 suspicious lesions were identified. Of the 127 intrahepatic lesions, 104 were malignant, and of the 39 extrahepatic lesions, 34 were malignant. Fluorine-18-fluorodeoxyglucose imaging was more accurate (92%) than CT and CT portography (78% and 80%, respectively) in detecting liver metastases and more accurate than CT for extrahepatic metastases (92% and 71%, respectively). Fluorine-18-fluorodeoxyglucose detected unsuspected metastases in 17 patients and altered surgical management in 28% of patients., Conclusion: These data identify that 18FDG-PET is the most accurate noninvasive method for staging patients with recurrent metastatic colorectal carcinoma and plays an important role in management decisions in this setting.
- Published
- 1997
31. Positron emission tomography to stage suspected metastatic colorectal carcinoma to the liver.
- Author
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Vitola JV, Delbeke D, Sandler MP, Campbell MG, Powers TA, Wright JK, Chapman WC, and Pinson CW
- Subjects
- Deoxyglucose analogs & derivatives, Female, Fluorine Radioisotopes, Fluorodeoxyglucose F18, Follow-Up Studies, Humans, Liver Neoplasms surgery, Male, Middle Aged, Sensitivity and Specificity, Tomography, X-Ray Computed, Colorectal Neoplasms pathology, Liver Neoplasms diagnostic imaging, Liver Neoplasms secondary, Neoplasm Staging methods, Tomography, Emission-Computed
- Abstract
Background: Accurate detection of recurrent colorectal carcinoma remains a clinical challenge. Positron emission tomography (PET) using 18F-fluorodeoxyglucose (18FDG) is an imaging technique that allows direct evaluation of cellular metabolism. 18F-fluorodeoxyglucose PET was compared to computed tomography (CT) and CT portography for staging metastatic colorectal carcinoma., Patients and Methods: Twenty-four patients previously treated for colorectal carcinoma who had suspected recurrence to the liver underwent an 18FDG PET scan of the entire body. All patients had either a CT scan of the abdomen (n = 17), a CT portogram (n = 18), or both (n = 11). The final diagnosis was obtained by tissue pathology in 19 patients and clinical follow-up in 5 patients., Results: A total of 60 suspicious lesions were identified. Of the 55 intrahepatic lesions, 39 were malignant and 16 were benign. Of the 5 extra-hepatic lesions, 4 were malignant. The 18FDG PET imaging had a higher accuracy (93%) than CT and CT portography (both 76%) in detecting metastatic disease to the liver, and detected unsuspected extrahepatic recurrence in 4 patients. Although the sensitivity of 18FDG PET (90%) was slightly lower than that of CT portography (97%), the specificity was much higher (100% versus 9%), including postsurgical sites. 18FDG PET altered surgical plans in 6 (25%) of 24 patients., Conclusions: 18FDG PET is extremely useful in staging patients with suspected metastatic colorectal carcinoma to the liver.
- Published
- 1996
- Full Text
- View/download PDF
32. Right ventricular performance and mass by use of cine MRI late after atrial repair of transposition of the great arteries.
- Author
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Lorenz CH, Walker ES, Graham TP Jr, and Powers TA
- Subjects
- Adolescent, Adult, Blood Volume, Cardiac Output, Child, Preschool, Female, Heart Atria surgery, Heart Ventricles anatomy & histology, Humans, Infant, Male, Postoperative Period, Stroke Volume, Transposition of Great Vessels pathology, Transposition of Great Vessels physiopathology, Ventricular Function, Left, Heart Ventricles pathology, Magnetic Resonance Imaging, Cine, Transposition of Great Vessels surgery, Ventricular Function, Ventricular Function, Right
- Abstract
Background: The long-term adaptation of the right ventricle after atrial repair of transposition of the great arteries (TGA) remains a subject of major concern. Cine magnetic resonance imaging (MRI), with its tomographic capabilities, allows unique quantitative evaluation of both right and left ventricular function and mass. Our purpose was to use MRI and an age-matched normal population to examine the typical late adaptation of the right and left ventricles after atrial repair of TGA., Methods and Results: Cine MRI was used to study ventricular function and mass in 22 patients after atrial repair of TGA. Images were obtained in short-axis sections from base to apex to derive normalized right and left ventricular mass (RVM and LVM, g/m2), interventricular septal mass (IVSM, g/m2), RV and LV end-diastolic volumes (EDV, mL/m2), and ejection fractions (EF). Results 8 to 23 years after repair were compared with analysis of 24 age- and sex-matched normal volunteers and revealed markedly elevated RVM, decreased LVM and IVSM, normal RV size, and only mildly depressed RVEF. Only 1 of 22 patients had clinical RV dysfunction, and this patient had increased RVM., Conclusions: Cine MRI allows quantitative evaluation of both RV and LV mass and function late after atrial repair of TGA. Longitudinal studies that include these measurements should prove useful in determining the mechanism of late RV failure in these patients. On the basis of these early data, inadequate hypertrophy does not appear to be the cause of late dysfunction in this patient group.
- Published
- 1995
- Full Text
- View/download PDF
33. MRI of the knee in sarcoidosis: synovial and marrow involvement.
- Author
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Powers TA and Limbird TJ
- Subjects
- Adult, Female, Humans, Image Enhancement, Joint Diseases diagnosis, Bone Marrow Diseases diagnosis, Femur pathology, Knee Joint pathology, Magnetic Resonance Imaging methods, Sarcoidosis diagnosis, Synovial Membrane pathology, Tibia pathology
- Published
- 1994
- Full Text
- View/download PDF
34. Quantitative imaging of renal blood flow and function.
- Author
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Lorenz CH, Powers TA, and Partain CL
- Subjects
- Animals, Contrast Media, Humans, Image Enhancement methods, Kidney Function Tests methods, Radioactive Tracers, Diagnostic Imaging methods, Kidney physiology, Renal Artery pathology, Renal Circulation physiology
- Abstract
Noninvasive renal blood flow quantitation has been historically difficult, although radionuclide imaging methods for measuring related parameters of renal function such as glomerular filtration rate and effective renal plasma flow have been successful. Radionuclide methods have long played an important role in the evaluation of renal function, but recent advances in other modalities such as positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging (MRI) have the potential to provide information not available with nuclear medicine techniques. The high spatial resolution provided by these modalities, coupled with dynamic imaging of contrast agents or radioactive tracers, potentially could allow detailed clinical evaluation of regional renal function and blood flow. A specialized MR technique, diffusion-weighted imaging, also shows promise for providing information not otherwise available concerning the renal microcirculation. This report provides a brief review of the available clinical techniques for the evaluation of renal blood flow and function as well as new methods under investigation.
- Published
- 1992
- Full Text
- View/download PDF
35. Staging lung carcinoma with a Tc-99m labeled monoclonal antibody.
- Author
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Vansant JP, Johnson DH, O'Donnell DM, Stewart JR, Sonin AH, McCook BM, Powers TA, Salk DJ, Frist WH, and Sandler MP
- Subjects
- Carcinoma, Non-Small-Cell Lung pathology, Carcinoma, Non-Small-Cell Lung secondary, Carcinoma, Small Cell pathology, Carcinoma, Small Cell secondary, Female, Humans, Lung Neoplasms pathology, Male, Middle Aged, Neoplasm Staging, Technetium, Tomography, Emission-Computed, Single-Photon, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Small Cell diagnostic imaging, Lung Neoplasms diagnostic imaging, Radioimmunodetection
- Abstract
Thirty-three patients with biopsy-proven lung cancer and a total of 150 lesions diagnosed by conventional staging procedures were imaged using a Tc-99m labeled monoclonal Fab fragment of an IgG2B murine monoclonal antibody (MoAb) (NR-LU-10, NeoRx Corporation). Immunoscintigraphy demonstrated 100% of primary and 78% of metastatic lesions. MoAb imaging detected 88% of lesions in 12 small cell lung cancer (SCLC) patients and 77% of lesions in 21 non-small cell lung cancer (NSCLC) patients. Based on initial evaluation by other methods, 29 sites of MoAb activity were not associated with evidence of disease. Eleven of these were subsequently shown to represent sites of metastases; 18 remain unconfirmed. Four of ten patients studied with limited NSCLC had eight unsuspected lesions on MoAb imaging. Confirmation of unsuspected lesions in two patients altered initial clinical staging, and surgical therapy was abandoned. This study demonstrates that Tc-99m labeled NR-LU-10 can accurately stage patients with lung cancer.
- Published
- 1992
- Full Text
- View/download PDF
36. Abdominal case of the day. Interruption of the inferior vena cava with azygos continuation.
- Author
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Powers TA
- Subjects
- Adult, Azygos Vein diagnostic imaging, Female, Humans, Radiography, Vena Cava, Inferior diagnostic imaging, Azygos Vein abnormalities, Vena Cava, Inferior abnormalities
- Published
- 1992
- Full Text
- View/download PDF
37. A measure of overt self-criticism: validation and correlates.
- Author
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Powers TA and Zuroff DC
- Subjects
- Depressive Disorder diagnosis, Depressive Disorder psychology, Female, Humans, Male, Psychometrics, Social Desirability, Personality Inventory statistics & numerical data, Self Concept
- Abstract
A measure of overt self-criticism was constructed and validated for 38 high and low scorers out of 300 undergraduates, using reports by knowledgeable others.
- Published
- 1992
- Full Text
- View/download PDF
38. Obstruction of the inferior vena cava: a multiple-modality demonstration of causes, manifestations, and collateral pathways.
- Author
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Sonin AH, Mazer MJ, and Powers TA
- Subjects
- Collateral Circulation, Constriction, Pathologic diagnosis, Constriction, Pathologic diagnostic imaging, Constriction, Pathologic etiology, Humans, Magnetic Resonance Imaging, Tomography, X-Ray Computed, Vascular Diseases diagnosis, Vascular Diseases diagnostic imaging, Vascular Diseases etiology, Vena Cava, Inferior diagnostic imaging, Vena Cava, Inferior pathology
- Abstract
This article explores the causes and manifestations of obstruction of the inferior vena cava (IVC) with a multiple-modality approach. Caval obstruction may be due to thrombus, extension of a tumor, extrinsic compression, or intrinsic caval disease. Evaluation of the IVC should be tailored to the individual circumstance; no single modality is best in all situations. Although magnetic resonance offers multiplanar imaging, vena cavography or ultrasound are often necessary to exclude intraluminal tumor extension. Computed tomography is sensitive for intracaval thrombus and compression but does not delineate the hepatic IVC well. Nuclear venography demonstrates well the resultant collateral pathways, which can be separated into the deep, intermediate, superficial, and portal systems. Despite the clear visualization of these pathways with this modality, congenital caval anomalies, such as caval interruption with azygos continuation, can be confused with acquired caval disease.
- Published
- 1992
- Full Text
- View/download PDF
39. Family origins of adolescent self-criticism and its continuity into adulthood.
- Author
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Koestner R, Zuroff DC, and Powers TA
- Subjects
- Adolescent, Adult, Aggression psychology, Child, Child Development, Child, Preschool, Depressive Disorder etiology, Humans, Longitudinal Studies, Mother-Child Relations, Prospective Studies, Regression Analysis, Self Concept, Sex Factors, Aging psychology, Parent-Child Relations, Personality Development, Self-Assessment
- Abstract
We used a prospective longitudinal design to examine the relation between parenting experiences at age 5 and level of self-criticism at age 12 and the stability of self-criticism from age 12 to age 31 in 156 subjects. The results showed that mothers' reports of parenting behaviors that reflect restrictiveness and rejection were related to the development of self-criticism, particularly when received from the same-sex parent. Partial correlational analyses revealed that the parenting-self-criticism relations remained significant when the mother's report of the child's early temperament was statistically controlled. The results also showed that for women, self-criticism was very stable from early adolescence to young adulthood. By contrast, there was no relation between self-criticism at ages 12 and 31 for men; however, there was a strong relation for men between age 12 self-criticism and inhibited aggressive impulses at age 31.
- Published
- 1991
- Full Text
- View/download PDF
40. Renal artery stenosis: in vivo perfusion MR imaging.
- Author
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Powers TA, Lorenz CH, Holburn GE, and Price RR
- Subjects
- Animals, Constriction, Pathologic, Dogs, Renal Artery Obstruction physiopathology, Renal Circulation, Magnetic Resonance Imaging, Renal Artery Obstruction diagnosis
- Abstract
The intravoxel incoherent motion (IVIM) model of perfusion and diffusion imaging was applied to an in vivo canine model of unilateral renal artery stenosis and was compared with relative renal blood flow determination with radioactive microspheres. The percentage relative renal blood flow as determined with radioactive microspheres correlated closely with the percentage apparent diffusion coefficient. If this method can be adapted to human imaging, it may provide a noninvasive means for detecting renal artery stenosis.
- Published
- 1991
- Full Text
- View/download PDF
41. Imaging of the temporomandibular joint.
- Author
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Nance EP Jr and Powers TA
- Subjects
- Arthrography, Humans, Magnetic Resonance Imaging, Temporomandibular Joint Disorders diagnostic imaging, Temporomandibular Joint Disorders diagnosis
- Abstract
Both arthrography and MR imaging are of proven value in the evaluation of internal derangements of the TMJ. Arthrography provides the advantages of a dynamic display of joint mechanics and the easy detection of disc perforation. Its disadvantages include its technical difficulty and its poor visualization of the disc in the medial-lateral plane. MR imaging of the TMJ provides excellent soft-tissue detail and more readily demonstrates medial and lateral displacements of the disc. Unfortunately, perforations of the disc or ligaments are not usually visualized, and bony detail is not seen as well as on plain radiographs or computed tomography. In addition, real-time dynamic imaging of joint mechanics is not readily available. Currently, the choice of imaging modality is based on the specific diagnostic question, and availability of arthrography and MR imaging.
- Published
- 1990
42. Hepatic abscesses can be echogenic with or without demonstrable gas.
- Author
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Jones TB and Powers TA
- Subjects
- Humans, Liver physiology, Gases, Liver Abscess diagnosis, Ultrasonography
- Published
- 1983
- Full Text
- View/download PDF
43. Radionuclide measurement of differential glomerular filtration rate.
- Author
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Powers TA, Stone WJ, Grove RB, Plunkett JM, Kadir S, Patton JA, and Bowen RD
- Subjects
- Animals, Creatinine metabolism, Dogs, Female, Infarction diagnostic imaging, Infarction physiopathology, Iothalamic Acid metabolism, Kidney blood supply, Kidney Glomerulus physiopathology, Pentetic Acid, Radionuclide Imaging, Technetium Tc 99m Dimercaptosuccinic Acid, Technetium Tc 99m Pentetate, Glomerular Filtration Rate, Succimer, Sulfhydryl Compounds, Technetium
- Abstract
The authors sought to determine whether radionuclides could provide a reasonable estimate of differential renal function in five normal dogs and six dogs with unilateral segmental renal infarction. Glomerular filtration rate (GFR) of each kidney was measured by the standard technique using constant infusions of 99mTc-DTPA, iothalamate, and creatinine following ureteral catheterization. These results were correlated with total GFR estimated by bolus injection of 99mTc-DTPA and analysis of the plasma 99mTc-DTPA disappearance curve obtained by blood sampling. Differential GFR was then calculated by multiplying the total GFR from double exponential analysis of this curve (DTPA2) by each of three measures of differential function. These include the percent differential uptake of 99mTc-DTPA and 99mTc-DMSA in the posterior projection as well as the geometric mean of 99mTc-DMSA uptake. There were good correlations between differential GFR calculated from iothalamate clearances obtained at ureteral catheterization and all noninvasive methods involving radionuclides and DTPA2 (r = 0.85 - 0.99). Single exponential analysis of the 99mTc-DTPA plasma disappearance curve was less satisfactory. The authors suggest that measurement of total and differential GFR calculated from plasma clearance of 99mTc-DTPA and external counting may be a useful method with potential clinical applications.
- Published
- 1981
- Full Text
- View/download PDF
44. Pseudoaneurysm of the left ventricle. Diagnosis by first pass scintigraphy.
- Author
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Dickinson CZ, Christenberry RH, Ertzner TW, Powers TA, Friesinger GC, Sandler MP, and Partain CL
- Subjects
- Heart Ventricles diagnostic imaging, Humans, Male, Middle Aged, Radionuclide Imaging, Technetium, Tin Polyphosphates, Heart Aneurysm diagnostic imaging, Technetium Tc 99m Pyrophosphate
- Abstract
False aneurysm of the left ventricle is a rare complication of myocardial infarction with a high propensity for late rupture. Timely diagnosis is important and surgical repair is curative in a high percentage of patients. A case in which a false left ventricular aneurysm was recognized by first pass radionuclide angiography and confirmed by contrast ventriculography is reported. Surgery was then performed successfully. The diagnosis of false left ventricular aneurysm using radionuclide angiography, as well as other diagnostic imaging modalities, is discussed.
- Published
- 1984
- Full Text
- View/download PDF
45. Re: defining renal anatomy and function with 99m Technetium dimercaptosuccinic acid: clinical and renographic correlation.
- Author
-
Powers TA and Stone WJ
- Subjects
- Humans, Pentetic Acid, Radionuclide Imaging, Technetium Tc 99m Dimercaptosuccinic Acid, Technetium Tc 99m Pentetate, Kidney diagnostic imaging, Succimer, Sulfhydryl Compounds, Technetium
- Published
- 1982
- Full Text
- View/download PDF
46. Gallbladder visualization with technetium-99m glucoheptonate: concise communication.
- Author
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Tyler JL and Powers TA
- Subjects
- Humans, Radionuclide Imaging, Gallbladder diagnostic imaging, Organotechnetium Compounds, Sugar Acids, Technetium
- Published
- 1982
47. Detection of obstructive uropathy using 99mtechnetium diethylenetriaminepentaacetic acid.
- Author
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Powers TA, Grove RB, Bauriedel JK, Orr SC, Melton RE, and Bowen RD
- Subjects
- Aged, Evaluation Studies as Topic, False Positive Reactions, Humans, Kidney Calculi diagnostic imaging, Male, Middle Aged, Radionuclide Imaging, Ureteral Obstruction diagnostic imaging, Urethral Obstruction diagnostic imaging, Urography, Urologic Diseases etiology, Pentetic Acid, Technetium, Urinary Tract diagnostic imaging, Urologic Diseases diagnostic imaging
- Abstract
A simple, accurate test with no morbidity and effective for the detection of urinary tract obstruction in patients with normal and impaired renal function would be of significant clinical use. We herein evaluate the ability of 99mtechnetium diethylenetriaminepentaacetic acid to detect the presence or absence of obstruction. Of 107 patients who underwent recent studies 31 had confirmation of the presence or absence of obstruction by excretory urography, retrograde pyelography or other definitive procedures. Patients were studied in the posterior projection wtih perfusion images after intravenous injection of 20 millicuries 99mtechnetium diethylenetriaminepentaacetic acid. Static images of the urinary tract were obtained from 1 to 30 minutes after injection with delayed images up to 24 hours. Obstruction were defined as abnormal retention of activity in the collecting system persisting in the delayed images. Diethylentriaminepentaacetic acid identified correctly 13 of 13 patients proved to have obstruction and 17 of 18 without obstruction. One falsely positive result was owing to pyelocaliectasis. These data indicate a sensitivity of 100 per cent, specificity of 94 per cent and accuracy of 97 per cent.
- Published
- 1980
- Full Text
- View/download PDF
48. Radionuclide measurement of differential glomerular filtration rate in urinary tract obstruction.
- Author
-
Powers TA, Stone WJ, Lowe BA, Patton JA, and Bowen RD
- Subjects
- Animals, Creatinine, Dogs, Female, Iothalamic Acid, Radionuclide Imaging, Technetium Tc 99m Dimercaptosuccinic Acid, Technetium Tc 99m Pentetate, Ureteral Obstruction physiopathology, Glomerular Filtration Rate, Pentetic Acid, Succimer, Sulfhydryl Compounds, Technetium, Ureteral Obstruction diagnostic imaging
- Abstract
In a previous study using dogs whose renal function was rendered asymmetric by unilateral infarction, the efficacy of technetium-99m (99mTc) DTPA and DMSA in measuring differential glomerular filtration rate (GFR) was demonstrated. The present study was undertaken to determine whether the same techniques were applicable to unilateral ureteral obstruction. Five normal dogs and nine dogs with partial unilateral ureteral obstruction had determination of glomerular filtration rate by standard techniques using constant infusions of iothalamate and creatinine after ureteral catheterization. These results were compared with total GFR as measured by single injection of 99mTc DTPA and analysis of the plasma disappearance curve. Calculated differential GFR was obtained by multiplying total GFR from double exponential analysis of this curve (DTPA2) by each of three measures of differential function. These included the percent differential uptake of 99mTc DTPA and 99mTC DMSA in the posterior projection as well as the geometric mean of 99mTc DMSA uptake. There were good correlations between differential GFR determined by iothalamate clearances at ureteral catheterization and all noninvasive methods involving radionuclides and DTPA2 ( r = 0.93-0.99). Single exponential analysis of the 99mTc DTPA plasma disappearance curve was less satisfactory than double exponential analysis. These results and those reported previously support the use of radionuclides in the determination of differential GFR in a variety of clinical situations.
- Published
- 1982
- Full Text
- View/download PDF
49. Diagnosis of gallbladder perforation by Tc-99m disofenin cholescintigraphy.
- Author
-
Powers TA and Melton RE
- Subjects
- Aged, Cholelithiasis complications, Gallbladder Diseases complications, Humans, Male, Radionuclide Imaging, Technetium Tc 99m Disofenin, Gallbladder Diseases diagnostic imaging, Imino Acids, Technetium
- Published
- 1982
- Full Text
- View/download PDF
50. Bone scanning after marrow biopsy: concise communication.
- Author
-
Tyler JL and Powers TA
- Subjects
- Bone and Bones diagnostic imaging, Diphosphonates, Humans, Radionuclide Imaging, Technetium, Biopsy, Needle adverse effects, Bone Marrow Examination methods, Bone and Bones injuries, Technetium Tc 99m Medronate analogs & derivatives
- Published
- 1982
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