282 results on '"R. Wojcik"'
Search Results
2. Baicalein Preconditioning Cardioprotection Involves Pro-Oxidant Signaling and Activation of Pyruvate Dehydrogenase
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Jing, Li, Wei-Tien, Chang, Gina, Qin, Kimberly R, Wojcik, Chang-Qing, Li, Chin-Wang, Hsu, Mei, Han, Xiangdong, Zhu, Terry L, Vanden Hoek, and Zuo-Hui, Shao
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Mice ,Complementary and alternative medicine ,Flavanones ,Animals ,General Medicine ,Nitric Oxide ,Pyruvates ,Reactive Oxygen Species ,Proto-Oncogene Proteins c-akt - Abstract
Preconditioning has a powerful protective potential against myocardial ischemia-reperfusion injury (I/R). Our prior work demonstrated that baicalein, a flavonoid derived from the root of Scatellaria baicalensis Georgi (also known as Huangqin), confers this preconditioning protection. This study further explored the mechanisms of baicalein preconditioning (BC-PC) in mouse cardiomyocytes. Cells were treated with baicalein (10 μM) for a brief period of time (10 min) prior to simulated ischemia 90 min/reperfusion for 180 min. Baicalein triggered an induction of a small amount of mitochondrial reactive oxygen species (ROS) prior to the initiation of ischemia, assessed by 6-carboxy-2′, 7′-dichlorodihydrofluorescein diacetate (6-carboxy-H2DCFDA). It also significantly increased cell viability measured by propidium iodide (PI) and lactate dehydrogenase and preserved mitochondrial membrane potential assessed by TMRM fluorescence intensity. Myxothiazol, a mitochondrial electron transport chain complex III inhibitor, partially blocked ROS generation induced by BC-PC and reduced cell viability. BC-PC increased phosphorylation of Akt (Thr308 and Ser473) and eNOS Ser1177, and nitric oxide (NO) production measured using 4,5-diaminofluorescein diacetate (DAF-2 DA, 1 μM). Akt inhibitor API-2 abolished Akt phosphorylation and reduced DAF-2 production and cell viability. In addition, BC-PC decreased phosphorylation of pyruvate dehydrogenase (PDH) reflecting upregulated PDH activity, and increased ATP production at 30 min during reperfusion. Taken together, baicalein preconditioning-induced cardioprotection involves pro-oxidant generation, activates survival signaling Akt/eNOS/NO, and improves metabolic recovery after I/R injury. Our work provides new perspectives on the effect of baicalein on cardiac preconditioning against I/R injury.
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- 2022
3. Physical Activity Surveillance in the United States for Work and Commuting
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Anna Zendell, Russell L Carson, Mary T. Imboden, Elizabeth Ablah, Alan M. Beck, Christina McDonough, Laurie P. Whitsel, Nicolaas P. Pronk, Anne L Escaron, Janet R. Wojcik, Cedric X. Bryant, Jammie Hopkins, David R. Anderson, Frederique Huneycutt, and Rebecca Bucklin
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Population Health ,Best practice ,Public Health, Environmental and Occupational Health ,Transportation ,Population health ,Benchmarking ,United States ,Workforce productivity ,Work (electrical) ,Environmental health ,Well-being ,Life expectancy ,Humans ,Sedentary Behavior ,Workplace ,Psychology ,Exercise ,Inclusion (education) - Abstract
OBJECTIVE To summarize and describe the current US surveillance systems that assess physical activity (PA) for work and commuting. METHODS An expert group conducted an environmental scan, generating a list (n = 18) which was ultimately reduced to 12, based on the inclusion of PA and/or sedentary behavior data. RESULTS The 12 surveys or surveillance systems summarized provide nationally representative data on occupational-level PA or individual-level PA at work, data on active commuting, some are scorecards that summarize workplace health best practices and allow benchmarking, and one is a comprehensive nationally representative survey of employers assessing programs and practices in different worksites. CONCLUSIONS The various surveillance systems and surveys/scorecards are disparate and need to be better analyzed and summarized to understand the impact of occupational-level PA and commuting on population health and well-being, life expectancy, and workforce productivity.
- Published
- 2021
4. Validity and Interinstrument Reliability of a Medical Grade Physical Activity Monitor in Older Adults
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William R. Wojcik, Myles W. O’Brien, and Jonathon R. Fowles
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03 medical and health sciences ,0302 clinical medicine ,business.industry ,Physical activity ,Medicine ,030229 sport sciences ,030212 general & internal medicine ,business ,human activities ,Reliability (statistics) ,Reliability engineering - Abstract
Wearable physical activity monitors are associated with an increase in user’s habitual physical activity levels. Most of the older adult population do not meet the national moderate- to vigorous-intensity physical activity (MVPA) recommendations and may benefit from being prescribed a physical activity monitor. The PiezoRx is a class one medical grade device that uses step rate thresholds to measure MVPA. The validity and reliability of the PiezoRx in measuring MVPA has yet to be determined in older persons. We assessed the validity and interinstrument reliability of the PiezoRx to measure steps and MVPA in older adults. Participants (n = 19; 68.8 ± 2.3 years) wore an Omron HJ-320 pedometer, ActiGraph GT3X accelerometer, and four PiezoRx monitors during a five-stage treadmill walking protocol. The PiezoRx devices were set at moderate physical activity and vigorous physical activity step rate thresholds (steps per minute) of 100/120, 110/130, adjusted for height and adjusted for height + fitness. The PiezoRx exhibited a stronger correlation (intraclass correlation coefficient = .82) with manually counted steps than the ActiGraph (intraclass correlation coefficient = .53) and Omron (intraclass correlation coefficient = .54) and had a low absolute percentage error (3 ± 6%). The PiezoRx with moderate physical activity/vigorous physical activity step thresholds adjusted to 110/130 was strongly correlated to indirect calorimetry (0.84, p
- Published
- 2021
5. Climate Change, Air Pollution, and Physical Inactivity: Is Active Transportation Part of the Solution?
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Melissa Bopp, Helaine M Alessio, Janet Walberg Rankin, Gretchen S Patch, David Rojas-Rueda, David R. Bassett, Melissa W. Roti, Brian B. Parr, and Janet R. Wojcik
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medicine.medical_specialty ,Car ownership ,Natural resource economics ,Public health ,Global warming ,Flooding (psychology) ,Air pollution ,Climate change ,Physical Therapy, Sports Therapy and Rehabilitation ,030229 sport sciences ,Particulates ,medicine.disease_cause ,03 medical and health sciences ,0302 clinical medicine ,Greenhouse gas ,medicine ,Environmental science ,Orthopedics and Sports Medicine - Abstract
Active transportation is defined as self-propelled, human-powered transportation modes, such as walking and bicycling. In this article, we review the evidence that reliance on gasoline-powered transportation is contributing to global climate change, air pollution, and physical inactivity and that this is harmful to human health. Global climate change poses a major threat to human health and in the future could offset the health gains achieved over the last 100 yr. Based on hundreds of scientific studies, there is strong evidence that human-caused greenhouse gas emissions are contributing to global climate change. Climate change is associated with increased severity of storms, flooding, rising sea levels, hotter climates, and drought, all leading to increased morbidity and mortality. Along with increases in atmospheric CO2, other pollutants such as nitrogen dioxide, ozone, and particulate matter (e.g., PM2.5) are released by combustion engines and industry, which can lead to pulmonary and cardiovascular diseases. Also, as car ownership and vehicle miles traveled have increased, the shift toward motorized transport has contributed to physical inactivity. Each of these global challenges has resulted in, or is projected to result in, millions of premature deaths each year. One of the ways that nations can mitigate the health consequences of climate change, air pollution, and chronic diseases is through the use of active transportation. Research indicates that populations that rely heavily on active transportation enjoy better health and increased longevity. In summary, active transportation has tremendous potential to simultaneously address three global public health challenges of the 21st century.
- Published
- 2021
6. The 2019 Conference on Health and Active Transportation: Research Needs and Opportunities
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Calvin P. Tribby, Janet R. Wojcik, Daniel A. Rodriguez, Ann Steedly, Michelle Lee, James F. Sallis, Jennifer D. Roberts, David Berrigan, Behram Wali, Ralph Buehler, Andrew L. Dannenberg, Kelly Rodgers, Binbin Peng, and Yochai Eisenberg
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medicine.medical_specialty ,Emerging technologies ,Health, Toxicology and Mutagenesis ,media_common.quotation_subject ,physical activity ,Transportation ,Review ,Toxicology ,Political science ,Pandemic ,medicine ,Humans ,Relevance (information retrieval) ,active transportation ,Exercise ,Built environment ,media_common ,business.industry ,SARS-CoV-2 ,Public health ,public health ,Public Health, Environmental and Occupational Health ,Equity (finance) ,COVID-19 ,Public relations ,built environment ,Systems analysis ,climate change ,Conceptual model ,Medicine ,business - Abstract
Active transportation (AT) is widely viewed as an important target for increasing participation in aerobic physical activity and improving health, while simultaneously addressing pollution and climate change through reductions in motor vehicular emissions. In recent years, progress in increasing AT has stalled in some countries and, furthermore, the coronavirus (COVID-19) pandemic has created new AT opportunities while also exposing the barriers and health inequities related to AT for some populations. This paper describes the results of the December 2019 Conference on Health and Active Transportation (CHAT) which brought together leaders from the transportation and health disciplines. Attendees charted a course for the future around three themes: Reflecting on Innovative Practices, Building Strategic Institutional Relationships, and Identifying Research Needs and Opportunities. This paper focuses on conclusions of the Research Needs and Opportunities theme. We present a conceptual model derived from the conference sessions that considers how economic and systems analysis, evaluation of emerging technologies and policies, efforts to address inclusivity, disparities and equity along with renewed attention to messaging and communication could contribute to overcoming barriers to development and use of AT infrastructure. Specific research gaps concerning these themes are presented. We further discuss the relevance of these themes considering the pandemic. Renewed efforts at research, dissemination and implementation are needed to achieve the potential health and environmental benefits of AT and to preserve positive changes associated with the pandemic while mitigating negative ones.
- Published
- 2021
7. 30 Year Trends of Reduced Physical Fitness in Undergraduate Students Studying Human Movement
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Myles W. O’Brien, Madeline E. Shivgulam, William R. Wojcik, Brittany A. Barron, Roxanne E. Seaman, and Jonathon R. Fowles
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Adult ,Male ,university students ,kinesiology ,physical education ,physical fitness ,objectively measured physical activity ,Canada ,Physical Fitness ,Health, Toxicology and Mutagenesis ,Public Health, Environmental and Occupational Health ,Humans ,Female ,Sedentary Behavior ,Students ,Exercise - Abstract
The physical fitness of Canadian adults has decreased over the past 30 years, while sedentary time has increased. However, it is unknown if university students studying human movement exhibit similar population declines. Physical fitness (i.e., anthropometrics, musculoskeletal fitness, and aerobic fitness) and habitual activity (e.g., physical activity, stationary time, etc.) was measured in a cohort of kinesiology students (Post30; 2010–2016; n = 129 males, 224 females) using standardized fitness testing and accelerometry, respectively. Physical fitness was compared to data collected on a cohort of students from the same institution and program, 30 years prior (i.e., Pre, 1984–1987, n = 103 males, 73 females). Post30 had greater waist circumference (males: 83.6 ± 9.1 cm vs. 77.8 ± 8.3 cm, females: 77.1 ± 9.7 cm vs. 70.3 ± 5.2 cm, both p < 0.001) and lower estimated maximal aerobic fitness (males: 55 ± 11 vs. 63 ± 7, females: 45 ± 10 vs. 50 ± 7 mLO2/kg/min, both, p < 0.001). Compared to Pre, male Post30 vertical jump (53.6 ± 10.2 vs. 57.0 ± 8.4 cm, p = 0.04) and female Post30 broad jump (178.7 ± 22.1 vs. 186.0 ± 15.5 cm, p < 0.001) were lower. A subsample (n = 65) of Post30 whose habitual activity was assessed, met the aerobic portion of Canadian physical activity guidelines (~400 min/week), but spent excessive amounts of time stationary (10.7 h/day). Current kinesiology students may not be immune to population decreases in physical fitness. Relative to previous group of students interested in movement, fitness was lower in our sample, potentially attributed to excessive stationary time. Regular assessment of physical fitness in kinesiology curriculums may be valuable to understand these declining trends in undergraduate students that mimic population declines in fitness.
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- 2022
8. Development of outdoor learning environments at elementary and middle schools in Rock Hill, South Carolina, USA
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Janet R. Wojcik, Thomas Bell, Danielle Center, and Nicole McAden
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Urban Studies ,South carolina ,Footprint (electronics) ,Geography ,Outdoor learning ,business.industry ,Environmental resource management ,Public Health, Environmental and Occupational Health ,Physical activity ,business - Abstract
When new schools are built in the United States, they are often constructed on large parcels of land in suburban areas to account for the building footprint and automobile parking. Even if the scho...
- Published
- 2019
9. Climate Change, Air Pollution, and Physical Inactivity: Is Active Transportation Part of the Solution?
- Author
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Helaine M, Alessio, David R, Bassett, Melissa J, Bopp, Brian B, Parr, Gretchen S, Patch, Janet W, Rankin, David, Rojas-Rueda, Melissa W, Roti, and Janet R, Wojcik
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Greenhouse Gases ,Cardiorespiratory Fitness ,Air Pollution ,Humans ,Transportation ,Walking ,Sedentary Behavior ,Exercise ,Global Warming ,United States ,Bicycling - Abstract
Active transportation is defined as self-propelled, human-powered transportation modes, such as walking and bicycling. In this article, we review the evidence that reliance on gasoline-powered transportation is contributing to global climate change, air pollution, and physical inactivity and that this is harmful to human health. Global climate change poses a major threat to human health and in the future could offset the health gains achieved over the last 100 yr. Based on hundreds of scientific studies, there is strong evidence that human-caused greenhouse gas emissions are contributing to global climate change. Climate change is associated with increased severity of storms, flooding, rising sea levels, hotter climates, and drought, all leading to increased morbidity and mortality. Along with increases in atmospheric CO2, other pollutants such as nitrogen dioxide, ozone, and particulate matter (e.g., PM2.5) are released by combustion engines and industry, which can lead to pulmonary and cardiovascular diseases. Also, as car ownership and vehicle miles traveled have increased, the shift toward motorized transport has contributed to physical inactivity. Each of these global challenges has resulted in, or is projected to result in, millions of premature deaths each year. One of the ways that nations can mitigate the health consequences of climate change, air pollution, and chronic diseases is through the use of active transportation. Research indicates that populations that rely heavily on active transportation enjoy better health and increased longevity. In summary, active transportation has tremendous potential to simultaneously address three global public health challenges of the 21st century.
- Published
- 2021
10. A Pain in the Neck: An Atypical Presentation of Squamous Cell Carcinoma in Double-Lung Transplant
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J.M. Pilewski, R. Wojcik, and M. Acho
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Pathology ,medicine.medical_specialty ,Double lung transplant ,business.industry ,Medicine ,Basal cell ,Presentation (obstetrics) ,business - Published
- 2020
11. Comparison of Strength Gains in Untrained College-Age Females Using Free Weights and FreeMotion Machines
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Charles J. Bowers, Katherine Milton, Joni M. Boyd, and Janet R. Wojcik
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medicine.medical_specialty ,Strength training ,business.industry ,Physical fitness ,Repeated measures design ,Squat ,Physical strength ,Bench press ,Physical therapy ,medicine ,Dumbbell ,Exercise physiology ,business ,Mathematics - Abstract
Resistance training has become a preferred method for developing muscular strength among various populations. A variety of resistance training modes are available, but there are mixed outcomes regarding strength development among barbells, dumbbells, and weight machines. The purpose of this study was to investigate the differences in strength improvements between dumbbell and FreeMotion machine training. Twenty college-age females were randomly assigned into dumbbell or FreeMotion groups, but only 8 in the dumbbell group completed. Both groups followed a nearly identical progressive strength training program on each of their training modes for 8 weeks. Participants were tested on their one-repetition max (1-RM) on a barbell bench press and barbell back squat before and after the intervention program. A repeated measures ANOVA analysis compared 1-RM changes between groups, and effect sizes were calculated. Significant increases in strength improvements (p < .001) were observed for the dumbbell and FreeMotion groups, with moderate effect size for the 1-RM barbell bench press (d = 0.56) and a moderate to large effect size for the 1-RM barbell back squat (d = 0.73). There was no Group × Time interaction for the strength tests (p = .201 for 1-RM barbell bench press and p = .816 for the 1-RM barbell back squat, respectively). Dumbbells and FreeMotion machines were equally effective in improving strength in college-age females. The findings add to the literature on FreeMotion machines and benefit novice resistance trainers, physical educators, and fitness professionals. The study should be replicated with additional populations. Subscribe to TPE
- Published
- 2018
12. Aging and the Social Cognitive Determinants of Physical Activity Behavior and Behavior Change: Evidence from the Guide to Health Trial
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Eileen Smith Anderson-Bill, Richard A. Winett, Janet R. Wojcik, and David M. Williams
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Geriatrics ,RC952-954.6 - Abstract
Part one of this study investigated the effect of aging on social-cognitive characteristics related to physical activity (PA) among adults in the baseline phase of a health promotion intervention. Participants' questionnaire responses and activity logs indicated PA levels and self-efficacy declined with age, while social support and the use of self-regulatory behaviors (e.g., goal setting, planning, and keeping track) increased. With age participants were also less likely to expect PA to interfere with their daily routines and social obligations. Part two of the study was among overweight/obese, inactive participants completing the intervention; it examined whether improvements in psychosocial variables might counteract declining PA associated with age. After treatment, participants were more active and decreased body weight regardless of age, and improved self-efficacy, outcome expectations, and self-regulatory behaviors. In a causal model, increases in self-efficacy at 7-months lead to increased PA levels and, albeit marginally, weight loss at 16 months; increased PA was associated with greater weight loss. Aging adults who were more confident exercised more and as a result lost more weight. This longitudinal study suggests interventions that offset the effect of aging on self-efficacy may be more successful in helping older participants become more active and avoid weight gain.
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- 2011
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13. A pilot study: Validity and reliability of the CSEP−PATH PASB-Q and a new leisure time physical activity questionnaire to assess physical activity and sedentary behaviours
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Christopher Shields, Lisette d’Entremont, William R. Wojcik, Jonathon R. Fowles, and Myles W. O’Brien
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Male ,Canada ,medicine.medical_specialty ,Physiology ,Endocrinology, Diabetes and Metabolism ,Health Behavior ,Leisure time ,Physical activity ,Validity ,Pilot Projects ,Body Mass Index ,03 medical and health sciences ,Leisure Activities ,Oxygen Consumption ,0302 clinical medicine ,Physical medicine and rehabilitation ,Surveys and Questionnaires ,Physiology (medical) ,Accelerometry ,medicine ,Humans ,030212 general & internal medicine ,Exercise physiology ,Exercise ,Reliability (statistics) ,Aged ,Nutrition and Dietetics ,Reproducibility of Results ,030229 sport sciences ,General Medicine ,Middle Aged ,Path (graph theory) ,Physical therapy ,Female ,Sedentary Behavior ,Waist Circumference ,Psychology - Abstract
The purpose of this study was to evaluate the accuracy of 2 newly developed physical activity questionnaires: the Canadian Society for Exercise Physiology (CSEP) Physical Activity and Sedentary Behaviour Questionnaire (PASB-Q) and a newly modified Leisure-Time Physical Activity Questionnaire (mLTPA-Q). These questionnaires were compared with objective measurements of physical activity and fitness (accelerometry and physiological assessments) in 35 adults, before and after a week of daily living activity. Objectively measured moderate- to vigorous-intensity aerobic physical activity (MVPA) was moderately correlated with the PASB-Q’s physical activity vital sign (PAVS) (r = 0.50, p = 0.004) and the mLTPA-Q (r = 0.56, p = 0.001). Bland−Altman plots suggest minimal bias from self-reported to objective measures of MVPA. The ability of PAVS to accurately distinguish who does and does not achieve Canadian physical activity guidelines was 83% and 60%, respectively, compared with 82% and 73% of the mLTPA-Q. Self-reported sedentary time was greatly underestimated in the PASB-Q compared with the objective measure (6.4 ± 3.5 vs 12.2 ± 1.2 h/day). The results of this study suggest the PASB-Q and mLTPA-Q are valid and reliable measures of adult physical activity and provide reasonable indication of those individuals who meet physical activity guidelines. Future questionnaire development should take into account the underestimation of time spent engaging in sedentary activities.
- Published
- 2017
14. Effects of Two Warm-up Programs on Balance and Isokinetic Strength in Male High School Soccer Players
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Dana M. Ghareeb, Alice J. McLaine, Janet R. Wojcik, and Joni M. Boyd
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Male ,Leg ,medicine.medical_specialty ,Adolescent ,Warm-Up Exercise ,Isokinetic strength ,Hamstring Muscles ,Physical Therapy, Sports Therapy and Rehabilitation ,030229 sport sciences ,General Medicine ,Quadriceps Muscle ,03 medical and health sciences ,0302 clinical medicine ,Torque ,Soccer ,Physical therapy ,medicine ,Humans ,Orthopedics and Sports Medicine ,Muscle Strength ,030212 general & internal medicine ,Muscle, Skeletal ,Psychology ,Balance (ability) - Abstract
Ghareeb, DM, McLaine, AJ, Wojcik, JR, and Boyd, JM. Effects of two warm-up programs on balance and isokinetic strength in male high school soccer players. J Strength Cond Res 31(2): 372-379, 2017-One of the most common warm-up programs used to prevent injury in soccer, FIFA11+, integrates aerobic, strength, and balance. The purpose of this study was to compare FIFA11+ to a new warm-up program (NWP) on balance and isokinetic strength of the quadriceps and hamstrings at 60, 180, and 300°·s in male high school soccer players. Participants at one school (n = 17) performed the NWP before practice for 6 weeks during one soccer season, whereas participants at another school (n = 17) performed FIFA11+. There were no differences at baseline. At posttest, players in NWP significantly improved (p0.01) in Overall Stability Index Balance, Anterior/Posterior Index Balance, and Medial Lateral Index with large effect sizes (ES)1.3. No changes were seen in FIFA11+. Isokinetic strength peak torque increased at 60°·s in the quadriceps and hamstrings in dominant and nondominant legs in NWP (p0.01, ES, 0.59-1.02) and in hamstrings in FIFA11+ (p ≤ 0.05, ES, 0.32-0.40). At 180°·s, NWP improved peak torque (p0.01, ES, 0.74-0.90) except hamstrings in the nondominant leg, whereas FIFA11+ showed improvements across all muscle groups (p0.01), but with smaller ES, 0.25-0.84. Both programs improved isokinetic peak torque at 300°·s except hamstrings in the nondominant leg in NWP, although ES were higher in NWP (ES, 0.60-1.03) than FIFA11+ (ES, 0.31-0.42). The NWP seems to be effective for soccer conditioning by improving balance and isokinetic strength.
- Published
- 2017
15. Opportunities for Employers to Support Physical Activity Through Policy
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Qaiser Mukhtar, Jessica Grossmeier, Stephenie C. Lemon, Nicolaas P. Pronk, Laurie P. Whitsel, Keshia M. Pollack, Janet R. Wojcik, and Elizabeth Ablah
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Essay ,business.industry ,Health Policy ,Health Behavior ,05 social sciences ,Occupational Health Services ,Public Health, Environmental and Occupational Health ,Physical activity ,Workplace culture ,Health Promotion ,Public relations ,Organizational Culture ,03 medical and health sciences ,Policy ,0302 clinical medicine ,Humans ,Medicine ,0501 psychology and cognitive sciences ,030212 general & internal medicine ,Workplace ,business ,Exercise ,Occupational Health ,050107 human factors - Published
- 2019
16. Age Dependent Differences in Seasonal Versus Perennial Allergen Sensitivity in Association with Severe Asthma
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R. Wojcik, M.L. Fajt, J.V. Fahy, E.R. Bleecker, D.A. Meyers, N.N. Jarjour, M. Castro, E. Israel, B.D. Levy, W. Phipatanakul, A.M. Fitzpatrick, S.C. Erzurum, B.M. Gaston, S.E. Wenzel, W.C. Moore, A.T. Hastie, and null Severe Asthma Research Program III
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Allergen ,Perennial plant ,business.industry ,Severe asthma ,Immunology ,Medicine ,Age dependent ,business ,medicine.disease_cause - Published
- 2019
17. Worksite Policies for Promoting Physical Activity
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Keshia M. Pollack, Jessica Grossmeier, Stephenie C. Lemon, Elizabeth Ablah, Laurie P. Whitsel, Nicolaas P. Pronk, Janet R. Wojcik, and Amanda Walker
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Health (social science) ,Time Factors ,business.industry ,Communication ,Public Health, Environmental and Occupational Health ,Physical activity ,Health Promotion ,United States ,Leadership ,Policy ,Environmental health ,Medicine ,Humans ,business ,Workplace ,Exercise - Published
- 2019
18. Editor's Desk: Promoting Physical Activity in the Workplace
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Laurie P. Whitsel, Russell R. Pate, Elizabeth Ablah, Stephenie C. Lemon, Nicolaas P. Pronk, Janet R. Wojcik, Amanda Walker, Jessica Grossmeier, Keshia M. Pollack, Cedric X. Bryant, Ross Arena, Leonard A. Kaminsky, David Berrigan, Peter T. Katzmarzyk, Chris Calitz, Jim Pshock, and Felipe Lobelo
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World Wide Web ,Health (social science) ,business.industry ,Public Health, Environmental and Occupational Health ,Physical activity ,Medicine ,Humans ,Health Promotion ,business ,Workplace ,Exercise ,United States ,Desk - Published
- 2019
19. PND51 Cladribine Tablets (CT) Versus Other Disease-Modifying Therapies in the Treatment of Relapsing-Remitting Multiple Sclerosis (RRMS) - Cost-Effectiveness Analysis
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J. Wieczorek, P. Zięba, Marcin P. Kaczor, R Wojcik, and D Pawlik
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Oncology ,medicine.medical_specialty ,business.industry ,Health Policy ,Multiple sclerosis ,Public Health, Environmental and Occupational Health ,Disease ,Cost-effectiveness analysis ,medicine.disease ,Relapsing remitting ,Internal medicine ,medicine ,Cladribine ,business ,medicine.drug - Published
- 2020
20. Sequential approach to joint flow-seismic inversion for improved characterization of fractured media
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Xinding Fang, Dennis McLaughlin, Yingcai Zheng, Daniel R. Burns, Michael Fehler, Peter K. Kang, Ruben Juanes, Stephen Brown, and R. Wojcik
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010504 meteorology & atmospheric sciences ,Inversion (geology) ,Inverse problem ,010502 geochemistry & geophysics ,01 natural sciences ,Highly sensitive ,Flow response ,Seismic inversion ,Seismic interpretation ,Petrology ,Geology ,Seismology ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Seismic interpretation of subsurface structures is traditionally performed without any account of flow behavior. Here we present a methodology for characterizing fractured geologic reservoirs by integrating flow and seismic data. The key element of the proposed approach is the identification—within the inversion—of the intimate relation between fracture compliance and fracture transmissivity, which determine the acoustic and flow responses of a fractured reservoir, respectively. Owing to the strong (but highly uncertain) dependence of fracture transmissivity on fracture compliance, the modeled flow response in a fractured reservoir is highly sensitive to the geophysical interpretation. By means of synthetic models, we show that by incorporating flow data (well pressures and tracer breakthrough curves) into the inversion workflow, we can simultaneously reduce the error in the seismic interpretation and improve predictions of the reservoir flow dynamics. While the inversion results are robust with respect to noise in the data for this synthetic example, the applicability of the methodology remains to be tested for more complex synthetic models and field cases.
- Published
- 2016
21. Reservoir characterization in an underground gas storage field using joint inversion of flow and geodetic data
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Birendra Jha, R. Wojcik, F. Bottazzi, M. Coccia, Bradford H. Hager, N. Bechor, Stefano Mantica, Dennis McLaughlin, Thomas A. Herring, and Ruben Juanes
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Natural gas storage ,Petroleum engineering ,Multiphase flow ,Computational Mechanics ,Geotechnical Engineering and Engineering Geology ,Physics::Geophysics ,Permeability (earth sciences) ,Geomechanics ,Mechanics of Materials ,Fluid dynamics ,Compressibility ,Reservoir modeling ,General Materials Science ,Geotechnical engineering ,Subsurface flow ,Geology - Abstract
Summary Characterization of reservoir properties like porosity and permeability in reservoir models typically relies on history matching of production data, well pressure data, and possibly other fluid-dynamical data. Calibrated (history-matched) reservoir models are then used for forecasting production and designing effective strategies for improved oil and gas recovery. Here, we perform assimilation of both flow and deformation data for joint inversion of reservoir properties. Given the coupled nature of subsurface flow and deformation processes, joint inversion requires efficient simulation tools of coupled reservoir flow and mechanical deformation. We apply our coupled simulation tool to a real underground gas storage field in Italy. We simulate the initial gas production period and several decades of seasonal natural gas storage and production. We perform a probabilistic estimation of rock properties by joint inversion of ground deformation data from geodetic measurements and fluid flow data from wells. Using an efficient implementation of the ensemble smoother as the estimator and our coupled multiphase flow and geomechanics simulator as the forward model, we show that incorporating deformation data leads to a significant reduction of uncertainty in the prior distributions of rock properties such as porosity, permeability, and pore compressibility. Copyright © 2015 John Wiley & Sons, Ltd.
- Published
- 2015
22. Beyond the Chief Complaint: Our Patients' Worries
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K J Tanabe, V M Staley, M A Melton, V M Chau, J To, J T Engeln, S J Khatter, S Axelrath, R Kwon, R Wojcik, and M C Reinsvold
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Male ,medicine.medical_specialty ,Health (social science) ,Patients ,Primary Health Care ,business.industry ,Health Policy ,education ,030208 emergency & critical care medicine ,Emergency department ,Patient-centered care ,Humanism ,03 medical and health sciences ,0302 clinical medicine ,Family medicine ,Surveys and Questionnaires ,Patient experience ,Complaint ,Medicine ,Humans ,Female ,030212 general & internal medicine ,business ,Emergency Service, Hospital ,Stress, Psychological - Abstract
Fourth-year medical students at the University of Colorado School of Medicine distributed cards to patients in the emergency department asking, "What Worries You Most?" The patients' responses provided insight about their most pressing concerns, often unrelated to their "chief complaints."
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- 2017
23. Design and characterization of a low profile NaI(Tl) gamma camera for dedicated molecular breast tomosynthesis
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Stan Majewski, Alexander Stolin, Justin Niestroy, Andrew M. Polemi, R. Wojcik, Mark B. Williams, and Gangadhar Jaliparthi
- Subjects
Physics ,Photomultiplier ,business.industry ,Detector ,X-ray detector ,Field of view ,Tomosynthesis ,Collimated light ,Article ,030218 nuclear medicine & medical imaging ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Optics ,law ,030220 oncology & carcinogenesis ,business ,Image resolution ,Gamma camera - Abstract
A new low profile gamma camera is being developed for use in a dual modality (x-ray transmission and gamma-ray emission) tomosynthesis system. Compared to the system’s current gamma camera, the new camera has a larger field of view (~20x25 cm) to better match the system’s x-ray detector (~23x29 cm), and is thinner (7.3 cm instead of 10.3 cm) permitting easier camera positioning near the top surface of the breast. It contains a pixelated NaI(Tl) array with a crystal pitch of 2.2 mm, which is optically coupled to a 4x5 array of Hamamatsu H8500C position sensitive photomultiplier tubes (PSPMTs). The manufacturer-provided connector board of each PSPMT was replaced with a custom designed board that a) reduces the 64 channel readout of the 8x8 electrode anode of the H8500C to 16 channels (8X and 8Y), b) performs gain non-uniformity correction, and c) reduces the height of the PSPMT-base assembly, 37.7 mm to 27.87 mm. The X and Y outputs of each module are connected in a lattice framework, and at two edges of this lattice, the X and Y outputs (32Y by 40X) are coupled to an amplifier/output board whose signals are fed via shielded ribbon cables to external ADCs. The camera uses parallel hole collimation. We describe the measured camera imaging performance, including intrinsic and extrinsic spatial resolution, detection sensitivity, uniformity of response, energy resolution for 140 keV gamma rays, and geometric linearity.
- Published
- 2017
24. Ensemble-based characterization of uncertain environmental features
- Author
-
Dara Entekhabi, R. Wojcik, Seyed Hamed Alemohammad, and Dennis McLaughlin
- Subjects
Ground truth ,Image fusion ,Pixel ,Computer science ,business.industry ,Dimensionality reduction ,Bayesian probability ,Pattern recognition ,Distinctive feature ,computer.software_genre ,Artificial intelligence ,Multidimensional scaling ,Data mining ,business ,computer ,Importance sampling ,Water Science and Technology - Abstract
This paper considers the characterization of uncertain spatial features that cannot be observed directly but must be inferred from noisy measurements. Examples of interest in environmental applications include rainfall patterns, solute plumes, and geological features. We formulate the characterization process as a Bayesian sampling problem and solve it with a non-parametric version of importance sampling. All images are concisely described with a small number of image attributes. These are derived from a multidimensional scaling procedure that maps high dimensional vectors of image pixel values to much lower dimensional vectors of attribute values. The importance sampling procedure is carried out entirely in terms of attribute values. Posterior attribute probabilities are derived from non-parametric estimates of the attribute likelihood and proposal density. The likelihood is inferred from an archive of noisy operational images that are paired with more accurate ground truth images. Proposal samples are generated from a non-stationary multi-point statistical algorithm that uses training images to convey distinctive feature characteristics. To illustrate concepts we carry out a virtual experiment that identifies rainy areas on the Earth’s surface from either one or two remote sensing measurements. The two sensor case illustrates the method’s ability to merge measurements with different error properties. In both cases, the importance sampling procedure is able to identify the proposals that most closely resemble a specified true image.
- Published
- 2014
25. Influence of Anthropometrics on Step-Rate Thresholds for Moderate and Vigorous Physical Activity in Older Adults: Scientific Modeling Study
- Author
-
Matthew J Kivell, William R. Wojcik, Myles W. O’Brien, Jonathon R. Fowles, Ghislain d'Entremont, and Derek S. Kimmerly
- Subjects
medicine.medical_specialty ,Health (social science) ,Physical activity ,STRIDE ,Health Informatics ,Metabolic equivalent ,walking ,03 medical and health sciences ,0302 clinical medicine ,Aerobic exercise ,Medicine ,030212 general & internal medicine ,Treadmill ,Original Paper ,business.industry ,aging ,public health ,030229 sport sciences ,Anthropometry ,physical activity intensity ,Physical therapy ,cadence ,Geriatrics and Gerontology ,business ,Cadence ,Gerontology ,Body mass index - Abstract
Background Adults and older adults are recommended to engage in 150 minutes of moderate (MPA) to vigorous (VPA) aerobic physical activity (MVPA) per week, with the heuristic message of 3000 steps in 30 minutes (100 steps per minute [spm]). However, this message is based on adult populations, with a paucity of research on step-rate thresholds that correspond to absolute MVPA (moderate=3 metabolic equivalents [METs], vigorous=6 METs) and relative MVPA (moderate=40% estimated METmax, vigorous=60% estimated METmax) in older persons, who have lower stride lengths and a lower exercise capacity. Also, there is a need to consider the influence of anthropometric differences when quantifying the relationship between step rate and intensity-related physical activity. Objective This study assessed absolute and relative MVPA step-rate thresholds and anthropometric factors (ie, height, leg length, and body mass index [BMI]) in older adults. Methods Nineteen older adults (7 females; age 69 years, SD 2, BMI 26 kg/m2, SD 4) completed a staged treadmill walking protocol: six minutes at 2.4, 3.2, 4.0, 5.6, and 6.4 km/h. Steps were manually counted and volume rate of oxygen consumed (VO2) was measured via indirect calorimetry. Aerobic fitness was estimated via the submaximal single-stage treadmill protocol. Results When BMI was considered, mixed effects modeling revealed absolute and relative MPA step-rate thresholds of 108 spm and 117 spm, respectively. Absolute and relative VPA corresponded to step rates of 135 spm and 132 spm, respectively. Neither height nor leg length improved the ability of the model to predict stepping cadence from METs. Conclusions In general, older adults need to walk faster than 100 spm (ie, approximately 110 spm) to reach MPA and in excess of approximately 130 spm to achieve VPA, depending on BMI status. Health care professionals and researchers should adjust cadence-based recommendations for differences in BMI in their older patients and consider using relative intensity to most appropriately tailor their physical activity recommendations.
- Published
- 2018
26. Sports Nutrition Knowledge among Mid-Major Division I University Student-Athletes
- Author
-
Joni M. Boyd, Ashley Andrews, Charles J. Bowers, and Janet R. Wojcik
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Article Subject ,Endocrinology, Diabetes and Metabolism ,education ,Certification ,Affect (psychology) ,Sports nutrition ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Track and field athletics ,lcsh:RC620-627 ,Medical education ,030109 nutrition & dietetics ,Nutrition and Dietetics ,business.industry ,030229 sport sciences ,Nutrition risk ,lcsh:Nutritional diseases. Deficiency diseases ,Coursework ,Physical therapy ,Lean body mass ,Student athletes ,business ,human activities ,Food Science ,Research Article - Abstract
Competitive athletes have goals to optimize performance and to maintain healthy body composition. Sports nutrition is a component of training programs often overlooked by student-athletes and their coaches. The purpose of this study was to examine student-athletes’ sports nutrition knowledge across sex, class level, team, and completion of prior nutrition coursework. Participants included 123 mid-major Division I university student-athletes (47 females and 76 males) from baseball, softball, men’s soccer, track and field, and tennis. The student-athletes completed a survey questionnaire to determine adequate sports nutrition knowledge (mean ≥ 75%). The overall mean sports nutrition knowledge score for the student-athletes was 56.9% which was considered inadequate sports nutrition knowledge (mean < 75%). Only 12 student-athletes achieved adequate sports nutrition knowledge score of 75% or higher. There were no differences by sex, class level, team, and completion of prior nutrition coursework. Student-athletes’ inadequate sports nutrition knowledge may place them at nutrition risk, lead to impaired performance, and affect their lean body mass and energy levels. Athletics personnel should not assume student-athletes have adequate sports nutrition knowledge. Athletic departments may make available a board certified Sports Dietitian or Registered Dietitian and offer classroom or online courses facilitating student-athletes to optimize nutrition knowledge and behaviors.
- Published
- 2016
27. A Comparison of the Fitness, Obesity, and Physical Activity Levels of High School Physical Education Students Across Race and Gender
- Author
-
Christi S. DeWaele, Janet R. Wojcik, and Kathryn L. Davis
- Subjects
Gerontology ,030505 public health ,business.industry ,education ,Physical fitness ,Physical activity ,Racial group ,030229 sport sciences ,medicine.disease ,Obesity ,Body fat percentage ,Physical activity level ,Physical education ,03 medical and health sciences ,Race (biology) ,0302 clinical medicine ,medicine ,0305 other medical science ,business - Abstract
Introduction: Little is known about the physical fitness, obesity, and physical activity (PA) levels of high school students in physical education classes when comparing racial and gender groups. Purpose : To compare the fitness, obesity, and PA levels of female and male students of different racial groups in 6 high schools in the southeastern United States. Methods : Three fitness measures (PACER, Modified Curl-Ups, and the Back-Saver Sit and Reach), as well as BMI, body fat percentage, and PA data, were obtained from 413 youth (216 females, 197 males, 14.8 ± .84 years). Additionally, fitness levels, prevalence of obesity, and PA patterns of genders and races were compared between groups. Results : Fitness, body fat, and PA data were significantly better for males than for females other than back-saver sit and reach, for which females performed higher. There were no gender differences in BMI. White students scored significantly better than Black students on fitness, body fat, PA, and BMI except back-saver sit and reach right side. Conclusions : The study suggests a strong need for more active physical education programs that are appropriate for developing the fitness and PA levels of high school students, especially females and Black students, and for programs that motivate students to improve their fitness and PA levels beyond and outside of high school.
- Published
- 2016
28. Blockade of Caspase-2 Activity Inhibits Ischemia/ Reperfusion-Induced Mitochondrial Reactive Oxygen Burst and Cell Death in Cardiomyocytes
- Author
-
Zuo-Hui Shao, Kimberly R. Wojcik, Yimin Qin, Chang-Qing Li, Terry L. Vanden Hoek, and Kimm J. Hamann
- Subjects
lcsh:Cytology ,lcsh:QH573-671 - Published
- 2011
29. Step Rate Thresholds Associated with Moderate and Vigorous Physical Activity in Adults
- Author
-
William R. Wojcik, Jonathon R. Fowles, Myles W. O’Brien, Ghislain d'Entremont, Derek S. Kimmerly, and Matthew J Kivell
- Subjects
Adult ,Male ,medicine.medical_specialty ,relative intensity ,Health, Toxicology and Mutagenesis ,Physical activity ,lcsh:Medicine ,Walking ,Treadmill walking ,Article ,03 medical and health sciences ,0302 clinical medicine ,Physical medicine and rehabilitation ,medicine ,Humans ,Body Weights and Measures ,030212 general & internal medicine ,absolute intensity ,Exercise ,Monitoring, Physiologic ,Relative intensity ,business.industry ,lcsh:R ,Public Health, Environmental and Occupational Health ,Calorimetry, Indirect ,030229 sport sciences ,Middle Aged ,Models, Theoretical ,Anthropometry ,step rate ,Female ,business ,human activities - Abstract
Adults are recommended to engage in 150 min of moderate (MPA) to vigorous (VPA) aerobic physical activity per week, with the public health message of obtaining 3000 steps in 30 min. There is a paucity of research on step rate thresholds that correspond to absolute MVPA (moderate = 3 METs, vigorous = 6 METs) with no research evaluating adult relative MVPA (moderate = 40% VO2max, vigorous = 60% VO2max). Anthropometric differences also influence intensity-related step rate thresholds. The purpose of this study was to identify step rates across a range of walking intensities so that mathematical models incorporating anthropometric factors could be used to identify individualized MVPA step rate thresholds. Forty-three adults (25♀, age = 39.4 ±, 15.2 years) completed a staged treadmill walking protocol with pedometers and indirect calorimetry: six-minutes at 2.4, 3.2, 4.0, 5.6, 6.4, 7.2 km/h. Mathematical modelling revealed absolute and relative MPA step rate thresholds of ~100 steps/minute (spm) and ~125 spm, respectively. VPA corresponded to step rates of ~133 spm and ~139 spm for absolute and relative thresholds respectively. The current public message of 3000 steps in 30 min is valid for absolute MPA. However, VPA is achieved at higher thresholds than previously reported, more than 130 spm for healthy adults.
- Published
- 2018
30. Conditioning Stochastic Rainfall Replicates on Remote Sensing Data
- Author
-
Alexandra G. Konings, Dara Entekhabi, Dennis McLaughlin, and R. Wojcik
- Subjects
Meteorology ,Ensemble forecasting ,Cloud top ,Ensemble learning ,law.invention ,Data assimilation ,law ,Geostationary orbit ,General Earth and Planetary Sciences ,Environmental science ,Weather radar ,Precipitation ,Electrical and Electronic Engineering ,Radar ,Remote sensing - Abstract
Temporally and spatially variable rainfall replicates are frequently required in hydrologic applications of ensemble forecasting and data assimilation. Ensemble methods can be expected to work better when the rainfall replicates more closely resemble observed storms. In particular, the replicates should capture the intermittency and variability that are dominant features of rainfall events. In this paper, we present a new probabilistic procedure for generating realistic rainfall replicates that are constrained by (or conditioned on) remote sensing measurements. The procedure uses remotely sensed cloud top temperatures to identify potentially rainy regions. The cloud top temperatures are obtained from visible/infrared instruments in geostationary orbit. A multipoint geostatistical algorithm generates areas of nonzero rain (rain clusters) within each cloudy region. This algorithm relies on statistics derived from ground-based weather radar [National Operational Weather Radar (NOWRAD)] data. A truncated multiplicative cascade generates rain rates within each rain cluster. A computational experiment based on summer 2004 data from the Central U.S. indicates that the rainfall replicates simulated by the procedure are visually and statistically similar to individual NOWRAD images and to a large ensemble of NOWRAD images collected throughout the summer simulation period.
- Published
- 2009
31. Prescribing Physical Activity: Applying the ACSM Protocols for Exercise Type, Intensity, and Duration Across 3 Training Frequencies
- Author
-
Richard A. Winett, James J. Annesi, Wayne L. Westcott, Eileen S. Anderson, Patrick J. Madden, and Janet R. Wojcik
- Subjects
Adult ,Male ,medicine.medical_specialty ,Time Factors ,Sports medicine ,Strength training ,Physical fitness ,Physical Therapy, Sports Therapy and Rehabilitation ,Physical medicine and rehabilitation ,medicine ,Humans ,Aerobic exercise ,Orthopedics and Sports Medicine ,Exercise physiology ,Exercise ,Societies, Medical ,Aged ,Aged, 80 and over ,Analysis of Variance ,business.industry ,Resistance Training ,Middle Aged ,United States ,Treatment Outcome ,Blood pressure ,Patient Satisfaction ,Physical Fitness ,Practice Guidelines as Topic ,Basal metabolic rate ,Body Composition ,Exercise intensity ,Physical therapy ,Patient Compliance ,Female ,business - Abstract
When physicians advise patients to attain more physical activity, they usually recommend a walking program. However, in a similar way to no exercise, those embarking on a walking program will typically lose 4 to 6 lb of lean weight and reduce their resting metabolic rate 2% to 3% every decade. These effects may be mitigated by the inclusion of resistance exercise. The American College of Sports Medicine (ACSM) minimum exercise guidelines recommend 20 minutes of aerobic activity 3 days per week, and 1 set (8-12 repetitions) of 8 to 10 resistance exercises to train the major muscle groups 2 days per week. However, large-scale testing of these recommendations in a field setting has been minimal. Men and women between 21 and 80 years (N = 1725) [corrected] participated in a 10-week combined strength and aerobic activity program based on the ACSM protocols for exercise intensity and duration across 3 training frequencies (1, 2, or 3 sessions/week). Across all training frequencies, mean changes included a reduction in body fat of 1.97%, a decrease in fat weight of 1.7 kg, an increase in lean weight of 1.35 kg, a reduction in systolic blood pressure of 3.83 mm Hg, and a reduction in diastolic blood pressure of 1.73 mm Hg. More frequent weekly training sessions were associated with greater improvements in body fat percent, fat weight, and lean weight. Participants responded favorably to the ACSM exercise program with a 91% completion rate and a 95% satisfaction rating. This article presents recommendations for prescribing safe, effective, and time-efficient exercise programs.
- Published
- 2009
32. Guide to health: Nutrition and physical activity outcomes of a group-randomized trial of an internet-based intervention in churches
- Author
-
Sheila G. Winett, Todd Bowden, Richard A. Winett, Eileen S. Anderson, and Janet R. Wojcik
- Subjects
Male ,Religion and Psychology ,medicine.medical_specialty ,Health Status ,Health Behavior ,Physical activity ,Psychological intervention ,Nutritional Status ,Guidelines as Topic ,Health Promotion ,Motor Activity ,Body weight ,law.invention ,Cognition ,Randomized controlled trial ,law ,Internet based ,Surveys and Questionnaires ,Intervention (counseling) ,medicine ,Humans ,Obesity ,Social Behavior ,General Psychology ,Internet ,business.industry ,Social Control, Informal ,Middle Aged ,Psychiatry and Mental health ,Pedometer ,Physical therapy ,Female ,business ,Body mass index ,Follow-Up Studies - Abstract
Theory-based interventions accessible to large groups of people are needed to induce favorable shifts in health behaviors and body weight.The aim was to assess nutrition; physical activity; and, secondarily, body weight in the tailored, social cognitive Guide to Health (GTH) Internet intervention delivered in churches.Participants (N = 1,071; 33% male, 23% African American, 57% with body mass indexor = 25, 60% sedentary, Mdn age = 53 years) within 14 Baptist or United Methodist churches were randomized to the GTH intervention only (GTH-Only; 5 churches), with church-based supports (GTH-Plus; 5 churches), or to a waitlist (control; 4 churches). Verified pedometer step counts, measured body weight, fat, fiber, and fruit and vegetable (FV) servings from food frequency and supermarket receipts were collected at pretest, posttest (7 months after pretest), and follow-up (16 months after pretest).Participants in GTH-Only increased FV at post (approximately 1.50 servings) compared to control (approximately 0.50 servings; p = .005) and at follow-up (approximately 1.20 vs. approximately 0.50 servings; p m = .038) and increased fiber at post (approximately 3.00 g) compared to control (approximately 1.5 g; p = .006) and follow-up (approximately 3.00 g vs. approximately 2.00 g; p = .040). GTH-Plus participants compared to control increased steps at post (approximately 1,500 steps/day vs. approximately 400 steps/day; p = .050) and follow-up (approximately 1,000 steps/day vs. approximately - 50 steps/day; p = .010), increased FV at post (approximately 1.5 servings; p = .007) and follow-up (approximately 1.3 servings; p = .014), increased fiber at post (approximately 3.00A g; p = .013), and follow-up (approximately 3.00; p = .050) and decreased weight at post (approximately - 0.30 kg vs. approximately + 0.60 kg; p = .030).Compared to control, both GTH treatments improved nutrition at posttest, but church supports improved physical activity and nutrition at posttest and follow-up, suggesting environmental supports may improve Internet-based interventions.
- Published
- 2007
33. Performance Evaluation of a Dedicated Camera Suitable for Dynamic Radiopharmaceuticals Evaluation in Small Animals
- Author
-
R. Wojcik, George Loudos, Konstantina S. Nikita, Alexandra D. Varvarigou, Stavros Xanthopoulos, S. Majewski, Nikolaos K. Uzunoglu, N. Sakellios, Penelope Bouziotis, and Andrew G. Weisenberger
- Subjects
Nuclear and High Energy Physics ,Technetium compounds ,Materials science ,Detector ,Collimator ,Scintillator ,Imaging phantom ,law.invention ,Nuclear Energy and Engineering ,law ,Technical university ,Medical imaging ,Electrical and Electronic Engineering ,Preclinical imaging ,Biomedical engineering - Abstract
As the result of a collaboration between the Detector and Imaging Group of Thomas Jefferson National Accelerator Facility (US), the Institute of Radioisotopes and Radiodiagnostic Products (IRRP) of N.C.S.R. ldquoDemokritosrdquo and the Biomedical Simulations and Imaging Applications Laboratory (BIOSIM) of National Technical University of Athens (Greece), a mouse sized camera optimized for Tc99m imaging was developed. The detector was built in Jefferson Lab and transferred to Greece, where it was evaluated with phantoms and small animals. The system will be used initially for planar dynamic studies in small animals, in order to assess the performance of new radiolabeled biomolecules for oncological studies. The active area of the detector is approximately 48 mm times 96 mm. It is based on two flat-panel Hamamatsu H8500 position sensitive photomultiplier tubes (PSPMT), a pixelated NaI(Tl) scintillator and a high resolution lead parallel-hole collimator. The system was developed to optimize both sensitivity and resolution for in vivo imaging of small animals injected with technetium compounds. The results of system evaluation in planar mode with phantoms are reported. Results are presented for in vivo dynamic studies of mice injected with > 100 muCi of two conventional and novel radiopharmaceuticals, namely Tc99m-MDP and Tc99m -Bombesin.
- Published
- 2007
34. Performance evaluation of a mouse-sized camera for dynamic studies in small animals
- Author
-
R. Wojcik, Andrew G. Weisenberger, Nikolaos K. Uzunoglu, Penelope Bouziotis, Konstantina S. Nikita, Alexandra D. Varvarigou, Stan Majewski, George Loudos, and Nicolas Sakellios
- Subjects
Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Photomultiplier ,business.industry ,Resolution (electron density) ,Detector ,Collimator ,Scintillator ,law.invention ,Optics ,Single view ,Mockup ,law ,medicine ,Medical physics ,Sensitivity (control systems) ,business ,Instrumentation - Abstract
A mouse sized camera has been built in terms of collaboration between the presenting institutions. The system is used for the performance of dynamic studies in small animals, in order to evaluate novel radiopharmaceuticals. The active area of the detector is approximately 48×96 mm allowing depiction of the entire mouse in a single view. The system is based on two flat-panel Hamamatsu H8500 position sensitive photomultiplier tubes (PSPMT), a pixellated NaI(Tl) scintillator and a copper–beryllium (CuBe) parallel-hole collimator. In this work, the evaluation results of the system are presented, using phantoms and small animals injected with conventional radiophrmaceuticals. Average resolution was ∼1.6 mm on the collimator surface and increased to ∼4.1 mm in 12 cm distance from the detector. The average energy resolution was measured and found to be ∼15.6% for Tc99m. Results from imaging thin capillaries demonstrated system's high resolution and sensitivity in activity variations was shown. Initial dynamic studies have been carried out in small animals injected with Tc99m-DTPA and Tc99m-MDP. The results show system's ability to perform kinetic imaging in small animals.
- Published
- 2007
35. Initial tests of a prototype MRI-compatible PET imager
- Author
-
S. Sendhil Velan, Andrew G. Weisenberger, Vladimir Popov, Susan K. Lemieux, Mark F. Smith, Stan Majewski, R. Wojcik, Raymond R. Raylman, and Brain Kross
- Subjects
Physics ,Nuclear and High Energy Physics ,Scanner ,Optical fiber ,medicine.diagnostic_test ,business.industry ,Instrumentation ,Detector ,Magnetic resonance imaging ,Imaging phantom ,law.invention ,Optics ,Nuclear magnetic resonance ,Mockup ,law ,Electromagnetic shielding ,medicine ,business - Abstract
Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5×5×4 cm3. Each MRI–PET detector module consists of an array of LSO detector elements (2.5×2.5×15 mm3) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of ∼60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to ∼85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy .
- Published
- 2006
36. Book reviews (2 books reviewed)
- Author
-
Z. Papir and R. Wojcik
- Subjects
Delay-tolerant networking ,Computer Networks and Communications ,Computer science ,Wireless network ,business.industry ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Communications system ,WiMAX ,Computer Science Applications ,Wireless broadband ,Wireless ,The Internet ,Electrical and Electronic Engineering ,business ,Telecommunications ,Wireless sensor network - Abstract
The following books are reviewed: Fundamentals of WiMAX: Understanding Broadband Wireless Networking (J.G. Andrews et al.; 2007); Delay- and Disruption-Tolerant Networking (S. Farrell and V. Cahill; 2006); and Wireless Sensor Networks: Technology, Protocols, and Applications (K. Sohraby et al.; 2007).
- Published
- 2006
37. Airway epithelial wound repair: role of carbohydrate sialyl Lewisx
- Author
-
Sima Allahverdian, Delbert R. Dorscheid, and Kimberly R. Wojcik
- Subjects
Adult ,Pulmonary and Respiratory Medicine ,Fucosyltransferase ,Physiology ,Glycoconjugate ,Carbohydrates ,Lewis X Antigen ,Oligosaccharides ,Bronchi ,Wounds, Nonpenetrating ,Antibodies ,Epithelium ,Lewis Blood Group Antigens ,Epidermal growth factor ,Physiology (medical) ,Humans ,Sialyl Lewis X Antigen ,Cells, Cultured ,chemistry.chemical_classification ,Wound Healing ,Epidermal Growth Factor ,biology ,Drug Synergism ,Epithelial Cells ,Cell Biology ,Carbohydrate ,Fucosyltransferases ,Cell function ,Cell biology ,chemistry ,Biochemistry ,biology.protein ,Carbohydrate Metabolism ,Respiratory epithelium ,E-Selectin ,Airway ,Selectin - Abstract
Epithelial repair is a complex cellular and molecular process, the details of which are still not clearly understood. Plasma membrane glycoconjugates can modulate cell function by altering the function of protein and lipids. Sialyl Lewisx(sLex), a fucose-containing tetrasaccharide, decorates membrane-bound and secreted proteins and mediates cell-cell interaction. In the present study we investigated the role of sLexin airway epithelial repair. Using immunohistochemistry, we showed an increased expression of sLexin areas of damaged bronchial epithelium compared with intact regions. Confluent monolayers of airway epithelial cells were mechanically wounded and allowed to close. Wounded monolayers were photographed for wound closure kinetics, fixed for immunocytochemical studies, or subjected to RNA extraction. Examining the expression of different α1,3-fucosyltransferases (FucT), enzymes that mediate the final step in the synthesis of sLex, we found that FucT-IV was the common gene expressed in all cell lines and primary airway epithelial cells. We demonstrated an increased expression of sLexover time after mechanical injury. Blocking of sLexwith an inhibitory antibody completely prevented epithelial repair. Our data suggest an essential functional role for sLexin epithelial repair. Further studies are necessary to explore the exact mechanism for sLexin mediating cell-cell interaction in bronchial epithelial cells to facilitate epithelial migration and repair.
- Published
- 2006
38. Gamma-Guided Stereotactic Breast Biopsy System
- Author
-
Vladimir Popov, R. Brem, B. Welch, S. Majewski, R. Wojcik, and Brian Kross
- Subjects
Breast biopsy ,Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Stereotactic biopsy ,medicine.diagnostic_test ,Point source ,business.industry ,Field of view ,Imaging phantom ,law.invention ,Nuclear Energy and Engineering ,law ,medicine ,Mammography ,Computer vision ,Medical physics ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Image resolution ,Gamma camera - Abstract
A gamma-ray imaging system has been developed for acquiring stereo images of the distribution of radiopharmaceuticals in breast tissue. The system consists of a small field-of-view gamma-ray camera mounted to a stereotactic biopsy table. The camera is mounted on a rotational arm such that it can be used to image the breast from two 15deg stereo views. These stereo images can be used to determine the three dimensional spatial location of a region of focal uptake. Once the location of this region is determined, this information can be used as a guide for stereotactic core needle biopsy. The accuracy that the spatial location of a source can be determined was investigated by moving a point source within the field of view. A center-of gravity calculation was used to localize the centroid of the image of the source and this was used to determine the spatial location. Measurements indicate that the source can be localized to within 1 mm. A comparison of the operation of the gamma imaging system and an x-ray imaging system has been done using a dual modality phantom. These measurements indicated that the spatial location of an isolated source can be determined by the gamma imaging system to within approximately the same performance criteria as required for the X-ray system (1 mm). Collimators were tested to determine the spatial resolution in the transverse dimension and the impact of this transverse resolution on the axial resolution was investigated. The performance of this gamma-guided stereotactic biopsy system will be presented
- Published
- 2006
39. Tri-modality small animal imaging system
- Author
-
L. Baumgart, Bijoy Kundu, Carl Zorn, M. Fontaine, J. Pole, Stanislaw Majewski, A.V. Stolin, Mark B. Williams, Brian Kross, and R. Wojcik
- Subjects
Physics ,Nuclear and High Energy Physics ,Scanner ,Modality (human–computer interaction) ,genetic structures ,medicine.diagnostic_test ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Attenuation ,Physics::Medical Physics ,Analytical chemistry ,Context (language use) ,Single-photon emission computed tomography ,Signal ,Light intensity ,Optics ,Nuclear Energy and Engineering ,medicine ,Electrical and Electronic Engineering ,business ,Preclinical imaging - Abstract
Our group is developing a scanner that combines x-ray, single gamma, and optical imaging on the same rotating gantry. Two functional modalities (SPECT and optical) are included because they have different strengths and weaknesses in terms of spatial and temporal decay lengths in the context of in vivo imaging, and because of the recent advent of multiple reporter gene constructs. The effect of attenuation by biological tissue on the detected intensity of the emitted signal was measured for both gamma and optical imaging. Attenuation by biological tissue was quantified for both the bioluminescent emission of luciferace and for the emission light of the near infrared fluorophore cyanine 5.5, using a fixed excitation light intensity. Experiments were performed to test the feasibility of using either single gamma or x-ray imaging to make depth-dependent corrections to the measured optical signal. Our results suggest that significant improvements in quantitation of optical emission are possible using straightforward correction techniques based on information from other modalities. Development of an integrated scanner in which data from each modality are obtained with the animal in a common configuration will greatly simplify this process.
- Published
- 2006
40. Social-cognitive determinants of physical activity: The influence of social support, self-efficacy, outcome expectations, and self-regulation among participants in a church-based health promotion study
- Author
-
Janet R. Wojcik, David M. Williams, Eileen S. Anderson, and Richard A. Winett
- Subjects
Adult ,Male ,Gerontology ,Adolescent ,Health Promotion ,Motor Activity ,Christianity ,Body Mass Index ,Social support ,Cognition ,Social cognition ,Surveys and Questionnaires ,Ethnicity ,Humans ,Sociology ,Applied Psychology ,Aged ,Demography ,Social influence ,Aged, 80 and over ,Self-efficacy ,Social perception ,Social Support ,Social environment ,Social Control, Informal ,Middle Aged ,Self Efficacy ,Psychiatry and Mental health ,Health promotion ,Social Perception ,Female ,Attitude to Health ,Social cognitive theory ,Clinical psychology - Abstract
A social-cognitive model of physical activity was tested, using structural equation analysis of data from 999 adults (21% African American; 66% female; 38% inactive) recruited from 14 southwestern Virginia churches participating in the baseline phase of a health promotion study. Within the model, age, race, social support, self-efficacy, and self-regulation contributed to participants' physical activity levels, but outcome expectations did not. Of the social-cognitive variables, self-regulation exerted the strongest effect on physical activity. Independent of self-regulation, self-efficacy had little effect. Social support influenced physical activity as a direct precursor to self-efficacy and self-regulation. The model provided a good fit to the data and explained 46% of the variance in physical activity among the diverse group of adults.
- Published
- 2006
41. A restraint-free small animal SPECT imaging system with motion tracking
- Author
-
Andrew G. Weisenberger, Shaun S. Gleason, Brian Kross, James S. Goddard, Vladimir Popov, R. Wojcik, Michael J. Paulus, B. Welch, Mark F. Smith, S. Majewski, Martin G. Pomper, and Steven R. Meikle
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Tracking system ,Iterative reconstruction ,Single-photon emission computed tomography ,law.invention ,Optics ,Nuclear Energy and Engineering ,Match moving ,law ,Spect imaging ,medicine ,Medical physics ,Electrical and Electronic Engineering ,business ,Image resolution ,Gamma camera - Abstract
We report on an approach toward the development of a high-resolution single photon emission computed tomography (SPECT) system to image the biodistribution of radiolabeled tracers such as Tc-99m and I-125 in unrestrained/unanesthetized mice. An infrared (IR)-based position tracking apparatus has been developed and integrated into a SPECT gantry. The tracking system is designed to measure the spatial position of a mouse's head at a rate of 10-15 frames per second with submillimeter accuracy. The high-resolution, gamma imaging detectors are based on pixellated NaI(Tl) crystal scintillator arrays, position-sensitive photomultiplier tubes, and novel readout circuitry requiring fewer analog-digital converter (ADC) channels while retaining high spatial resolution. Two SPECT gamma camera detector heads based upon position-sensitive photomultiplier tubes have been built and installed onto the gantry. The IR landmark-based pose measurement and tracking system is under development to provide animal position data during a SPECT scan. The animal position and orientation data acquired by the tracking system will be used for motion correction during the tomographic image reconstruction.
- Published
- 2005
42. Linear beam raster for cryogenic targets
- Author
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N. Sinkine, C. Yan, and R. Wojcik
- Subjects
Physics ,Nuclear and High Energy Physics ,business.industry ,Linearity ,Particle accelerator ,Cryogenics ,computer.file_format ,H bridge ,law.invention ,Nuclear magnetic resonance ,Optics ,Density distribution ,law ,Beam shaping ,Raster graphics ,Raster scan ,business ,Instrumentation ,computer - Abstract
Based on the H-bridge switch technique a linear beam raster system was developed in 2002. The system generates a rectangular raster pattern with highly uniform ( ∼ 95 % ) raster density distribution on cryogenic targets. The two raster frequencies are 24.96 and 25.08 kHz. The turning time at the vertex is 200 ns and the scan linearity is 98%. The beam-heating effect on the target is effectively eliminated. The new raster system allows the use of higher beam current toward 200 μ A in many of the experimental proposals at end station Hall A and Hall C of the Jefferson lab.
- Published
- 2005
43. Incorporation of a fluoroscopic X-ray modality in a small animal imaging system
- Author
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Vladimir Popov, Mark F. Smith, Paul E. Brewer, Amoreena Ranck, Stanislaw Majewski, K.K. Gleason, Eric L. Bradley, R. Wojcik, B. Kross, J Qian, Margaret S. Saha, Robert E. Welsh, Andrew G. Weisenberger, and K. Smith
- Subjects
Nuclear and High Energy Physics ,medicine.medical_specialty ,Photomultiplier ,Biodistribution ,Materials science ,Modality (human–computer interaction) ,medicine.diagnostic_test ,Fluoroscope ,X-ray ,Scintillator ,Nuclear Energy and Engineering ,medicine ,Fluoroscopy ,Medical physics ,Electrical and Electronic Engineering ,Image resolution ,Biomedical engineering - Abstract
The authors have developed a multimodality system for imaging the biodistribution of biologically interesting ligands tagged with /sup 125/I. By incorporating a small fluoroscope as an additional modality, they have enhanced their small animal nuclear imaging system to include both X-rays and images from two Hamamatsu R3292 5" diameter position sensitive photomultiplier tubes (PSPMT) viewing pixelated scintillators with image co-registration of 1.5 mm or better. Collimators placed between the animal and the scintillators can easily be interchanged and include CuBe parallel-hole collimators with a range of resolution and sensitivity combinations. The small X-ray fluoroscope provides 5 cm diameter images, several of which can readily be combined to provide structural anatomical information from the animal under study. The system has been tested by comparing the uptake of /sup 125/I (in NaI) in control mice and mice previously fed a solution of KI (potassium iodide) designed specifically to block uptake of the radiolabeled iodine in the thyroid. This system not only provides an effective approach for the analysis of KI dose and toxicity issues but also allows for detection of individual variation in animals, an important issue in contemporary pharmacology and genomics.
- Published
- 2003
44. Phantom study of radiotracer concentration quantification in breast scintigraphy
- Author
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Stanislaw Majewski, D. Kieper, D. Narayanan, Mark B. Williams, R. Wojcik, B. Welch, and M.J. More
- Subjects
Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Scanner ,medicine.diagnostic_test ,Breast imaging ,business.industry ,media_common.quotation_subject ,Attenuation ,Scintigraphy ,Imaging phantom ,law.invention ,Nuclear Energy and Engineering ,law ,medicine ,Contrast (vision) ,Mammography ,Medical physics ,Electrical and Electronic Engineering ,Nuclear medicine ,business ,media_common ,Gamma camera - Abstract
The authors are developing a breast imaging system that combines digital X-ray mammography and gamma emission scintigraphy in an integrated unit. One potential value of such a combination is the ability to quickly obtain information about breast shape and lesion position within the breast via X-ray and then to use this information to perform corrections to the gamma image(s). In particular, the effects of gamma ray attenuation, gamma camera resolution, and scatter can be taken into account so as to better estimate the difference between the image contrast and true radioactivity contrast. The authors present results of a phantom study designed to test how well the lesion-to-background contrast can be predicted by this method. The preliminary results indicate that the effects of attenuation, partial volume averaging, and scatter on lesion image contrast can be modeled and suggest that the model might be usefully employed in the dual modality breast scanner to correct the breast scintigram for these effects.
- Published
- 2003
45. SPECT-CT system for small animal imaging
- Author
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R. Wojcik, Paul E. Brewer, Margaret S. Saha, Eric L. Bradley, Andrew G. Weisenberger, K. Smith, Mark F. Smith, Robert E. Welsh, Amoreena Ranck, J Qian, and Stan Majewski
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,medicine.diagnostic_test ,business.industry ,Radiography ,Detector ,X-ray detector ,Iterative reconstruction ,Single-photon emission computed tomography ,Scintillator ,Optics ,Data acquisition ,Nuclear Energy and Engineering ,medicine ,Electrical and Electronic Engineering ,business - Abstract
The Detector Group at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) and the Biology, Physics, and Applied Sciences Departments at the College of William and Mary are collaborating on the development of a miniature dual modality SPECT-CT system for mouse imaging. The detector heads of the SPECT sub-system are designed to be capable of imaging the gamma- and X-ray emissions (28-35 keV) of the radioactive isotope iodine-125 (I-125). Two different sets of I-125 imaging detectors are configured on a gantry that has an open-barrel type design. One set of detector heads is based on the 1-in square Hamamatsu R5900-M64 position sensitive photomultiplier tube coupled to crystal scintillator arrays. The other detector heads configured on the gantry are two 5-in diameter Hamamatsu R3292-based compact gamma cameras. The X-ray radiographic projections are obtained using a LIXI Inc. model LF-85-503-OS X-ray imaging system that has an active area of 5.5 cm in diameter. The open-barrel shaped gantry facilitates the positioning of various mini gamma-ray imaging detectors and the X-ray system. The data acquisition and gantry control is interfaced through a Macintosh G3 workstation. Preliminary SPECT reconstruction results using the R5900 based detector are presented.
- Published
- 2003
46. Comparison of scintillators for positron emission mammography (PEM) systems
- Author
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Raymond R. Raylman, Stanislaw Majewski, Mark F. Smith, B. Kross, J.J. Derakhshan, Vladimir Popov, Andrew G. Weisenberger, and R. Wojcik
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,medicine.medical_specialty ,business.industry ,Resolution (electron density) ,Compton scattering ,Scintillator ,Optics ,Positron ,Nuclear Energy and Engineering ,medicine ,Positron emission mammography ,Gadolinium oxyorthosilicate ,Medical physics ,Electrical and Electronic Engineering ,business ,Image resolution - Abstract
Positron emission mammography (PEM) has promise as an effective method for the detection of breast lesions. Perhaps the most significant design feature of a PEM system is the choice of scintillator material. In this investigation we compared three scintillators for use in PEM: NaI(Tl), gadolinium oxyorthosilicate (GSO), and lutetium-gadolinium oxyorthosilicate (LGSO). The PEM systems consisted of two 30/spl times/30 arrays of pixelated scintillators (3/spl times/3/spl times/10 mm/sup 3/ for GSO and LGSO and 3/spl times/3/spl times/19 mm/sup 3/ for NaI(Tl)) coupled to arrays of square position-sensitive photomultiplier tubes. The Compton scatter fraction, system energy resolution, spatial resolution, spatial resolution uniformity, and detection sensitivity were compared. Compton scatter fractions for the systems were comparable, between 8% and 9%. The NaI(Tl) system produced the best system energy resolution (18.2%), the GSO system had the worst system energy resolution (28.7%). Spatial resolution for each system was relatively uniform across the face of the detectors, though the magnitude was dependent upon scintillator material. The NaI(Tl) system produced the lowest mean resolution (3.54/spl plusmn/0.05 mm for horizontal profiles and 3.51/spl plusmn/0.04 mm for vertical profiles), while the LGSO system produced the greatest mean spatial resolution (3.19/spl plusmn/0.04 mm for horizontal profiles and 3.20/spl plusmn/0.03 mm for vertical profiles). Detection sensitivity varied among the three systems: NaI(Tl)=217.7 c/s/kBq/ml, GSO=383.9 c/s/kBq/ml and LGSO=646.9 c/s/kBq/ml. Imaging of a simulated breast containing various sized spheres demonstrated that the LGSO system produced the greatest detectability for small spheres (as gauged by the contrast-to-noise ratio), while the NaI(Tl) system had the worst detectability. These differences were due mainly to the lower sensitivity of the NaI(Tl) system compared to the LGSO and GSO imagers. This investigation demonstrated the very important connection between scintillator selection and performance of PEM systems.
- Published
- 2003
47. Optimization of breast imaging procedure with dedicated compact gamma cameras
- Author
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D. Kieper, S. Majewski, R. Wojcik, M.J. More, Andrew G. Weisenberger, Allen R. Goode, G. Zhang, Vladimir Popov, Mark B. Williams, Brian Kross, and B. Welch
- Subjects
Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Scintimammography ,Planar Imaging ,Breast imaging ,business.industry ,media_common.quotation_subject ,Visibility (geometry) ,Detector ,law.invention ,Planar ,law ,medicine ,Contrast (vision) ,Medical physics ,Computer vision ,Artificial intelligence ,business ,Instrumentation ,Gamma camera ,media_common - Abstract
Results are presented on studies conducted with various prototypes of a dedicated small field-of-view (SFOV) gamma camera for use in radiopharmaceutical studies of the breast. Since the experience in the clinical use of such instruments is limited, these experiments were conducted to test various clinical imaging implementations. Both planar and tomographic techniques were utilized to image various compressed and noncompressed breast phantoms. Lesion contrast was used to quantify the lesion visibility of each case. The results of this study indicate that lesion contrast is optimized with planar imaging of the compressed breast and that contrast is also dependent on lesion-to-detector distance. Based on these observations, planar imaging conducted with a system comprised of two opposed detectors providing compression to the breast would be optimal. The opposed views would ensure the minimization of lesion-to-detector distance, especially for lesions whose location is not known a-priori.
- Published
- 2003
48. [Untitled]
- Author
-
Lesley D. Fox, William G. Herbert, Richard A. Winett, Janet R. Wojcik, Jennifer S. Blevins, and Ralph N. Carpinelli
- Subjects
medicine.medical_specialty ,business.industry ,Hemodynamics ,Physical exercise ,Cardiorespiratory fitness ,Surgery ,Psychiatry and Mental health ,Rate pressure product ,Blood pressure ,Internal medicine ,Heart rate ,medicine ,Cardiology ,Lung volumes ,business ,General Psychology ,Aerobic capacity - Abstract
A threshold model postulates that prescriptively applying the appropriate cardiorespiratory and strength stimulus at a designated threshold of intensity for a brief time results in the targeted adaptations. A randomized control group design was used with 17 unfit males and females (mean age = 37.1 ± 6.5 year) assigned to an exercise group (n = 9) who performed a progressive cardiovascular graded exercise protocol and resistance training twice a week for 12 weeks or a nonexercising control group (n = 8). The intervention included a graded exercise protocol involving a 3-min warm-up, exercising 3–4 min at 70–80% of maximum heart rate, and a 3-min cooldown. Progressive resistance exercise consisted of one set of six repetitions on each of six resistance machines. Results showed that the exercise group increased predicted aerobic capacity by 13.4% (p < 0.05), decreased submaximal rate pressure product by 17.2% (p < 0.05), and increased strength by 34% (p < 0.01). The results support a threshold model and show that time for effective exercise can be substantially reduced.
- Published
- 2003
49. Small field of view scintimammography gamma camera integrated to a stereotactic core biopsy digital X-ray system
- Author
-
B. Kross, Vladimir Popov, C. E. Keppel, Stanislaw Majewski, R. Wojcik, F. Barbosa, R. Hoefer, T.D. Green, Andrew G. Weisenberger, and D.C. Wymer
- Subjects
Physics ,Nuclear and High Energy Physics ,medicine.medical_specialty ,Photomultiplier ,Scintimammography ,medicine.diagnostic_test ,business.industry ,Radiography ,Collimator ,law.invention ,Optics ,Nuclear Energy and Engineering ,law ,medicine ,Mammography ,Medical physics ,Electrical and Electronic Engineering ,business ,Image resolution ,Digital radiography ,Gamma camera - Abstract
A small field of view gamma camera has been developed for integration with a commercial stereotactic core biopsy system. The goal is to develop and implement a dual-modality imaging system utilizing scintimammography and digital radiography to evaluate the reliability of scintimammography in predicting the malignancy of suspected breast lesions from conventional X-ray mammography. The scintimammography gamma camera is a custom-built mini gamma camera with an active area of 5.3 cm /spl times/ 5.3 cm and is based on a 2 /spl times/ 2 array of Hamamatsu R7600-C8 position-sensitive photomultiplier tubes. The spatial resolution of the gamma camera at the collimator surface is < 4 mm full-width at half-maximum and a sensitivity of /spl sim/ 4000 Hz/mCi. The system is also capable of acquiring dynamic scintimammographic data to allow for dynamic uptake studies. Sample images of preliminary clinical results are presented to demonstrate the performance of the system.
- Published
- 2002
50. A prototype coded aperture detector for small animal SPECT
- Author
-
Michael J. Fulham, Roger Fulton, R. Wojcik, Andrew G. Weisenberger, Stefan Eberl, Steven R. Meikle, Anatoly B. Rosenfeld, Mark F. Smith, Peter L. Kench, and Stan Majewski
- Subjects
Physics ,Nuclear and High Energy Physics ,Photomultiplier ,business.industry ,Detector ,Iterative reconstruction ,Imaging phantom ,Optics ,Nuclear Energy and Engineering ,Signal-to-noise ratio (imaging) ,Pinhole (optics) ,Coded aperture ,Electrical and Electronic Engineering ,business ,Image resolution - Abstract
In a previous simulation study, we demonstrated the feasibility of using coded apertures together with pixelated detectors tors for small animal SPECT. In this paper; we further explore the potential of this approach with a prototype detector and simulated multipinhole apertures. We also investigated the effect of multiplexing due to overlapped projections on convergence properties, image signal-to-noise ratio (SNR) and spatial resolution. The detector comprises a 48/spl times/44 array of NaI(Tl) crystals, each 1 mm/spl times/1 mm/spl times/5 mm on a 1.25-mm pitch. The crystal array is directly coupled to a Hamamatsu R3941 8 cm position sensitive photomultiplier tube. Multipinhole apertures were simulated by performing repeated SPECT acquisitions of the same object with a single tungsten pinhole translated to different positions in the aperture plane. Image reconstruction is based on a three-dimensional ray driven projector which is an extension of a method described for single pinhole SPECT with a displaced center of rotation. Image estimates are updated using the maximum likelihood expectation maximization (ML-EM) algorithm. The effect of multiplexing was to slow convergence and reduce the achievable SNR by approximately 15% compared with nonmultiplexed data (but the result may be achieved in a fraction of the time). The reconstructed resolution obtained with a resolution phantom was 1.5-mm full width at half maximum and there was no appreciable difference between the resolution of multiplexed and nonmultiplexed data. These results encourage us to develop a prototype coded aperture system for high sensitivity, high resolution small animal SPECT.
- Published
- 2002
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