2,709 results on '"Peterson, Michael P."'
Search Results
2. Air Population over the Great Plains
- Author
-
Peterson, Michael P. and Hunt, Paul
- Published
- 2018
3. Overview of the Current Challenges in Pulmonary Coccidioidomycosis.
- Author
-
Fayed, Mohamed, Evans, Timothy, Almasri, Eyad, Bilello, Kathryn, Libke, Robert, and Peterson, Michael
- Subjects
coccidioidomycosis ,lung mass ,pulmonary nodules ,pyopneumothorax ,valley fever - Abstract
Coccidioidomycosis is a disease caused by soil fungi of the genus Coccidioides, divided genetically into Coccidioides immitis (California isolates) and Coccidioides posadasii (isolates outside California). Coccidioidomycosis is transmitted through the inhalation of fungal spores, arthroconidia, which can cause disease in susceptible mammalian hosts, including humans. Coccidioidomycosis is endemic to the western part of the United States of America, including the central valley of California, Arizona, New Mexico, and parts of western Texas. Cases have been reported in other regions in different states, and endemic pockets are present in these states. The incidence of reported cases of coccidioidomycosis has notably increased since it became reportable in 1995. Clinically, the infection ranges from asymptomatic to fatal disease due to pneumonia or disseminated states. The recognition of coccidioidomycosis can be challenging, as it frequently mimics bacterial community-acquired pneumonia. The diagnosis of coccidioidomycosis is frequently dependent on serologic testing, the results of which can take several days or longer to obtain. Coccidioidomycosis continues to present challenges for clinicians, and suspected cases can be easily missed. The challenges of coccidioidomycosis disease, from presentation to diagnosis to treatment, remain a hurdle for clinicians, and further research is needed to address these challenges.
- Published
- 2024
4. Maps and the Meaning of the Cloud
- Author
-
Peterson, Michael P.
- Published
- 2015
5. Foraging behavior and age affect maternal transfer of mercury to northern elephant seal pups
- Author
-
Peterson, Sarah H., Peterson, Michael G., Ackerman, Joshua T., Debier, Cathy, Goetsch, Chandra, Holser, Rachel R., Hückstädt, Luis A., Johnson, Jennifer C., Keates, Theresa R., McDonald, Birgitte I., McHuron, Elizabeth A., and Costa, Daniel P.
- Published
- 2024
- Full Text
- View/download PDF
6. Efficient Production of Ferrous Sulfate from Steel Mill Scale Waste
- Author
-
Furmanski, Luana Milak, Muller, Thuani Gesser, Nuernberg, Julia Bortolotto, Martins, Monize Aparecida, Arnt, Ângela Beatriz Coelho, da Rocha, Marcio Roberto, Zaccaron, Alexandre, and Peterson, Michael
- Published
- 2024
- Full Text
- View/download PDF
7. Differentiating Lung Nodules Due to Coccidioides from Those Due to Lung Cancer Based on Radiographic Appearance.
- Author
-
Peterson, Michael W, Jain, Ratnali, Hildebrandt, Kurt, Carson, William Keith, and Fayed, Mohamed A
- Subjects
chest CT scan ,cocci nodule ,incidental nodule ,lung cancer ,lung cancer screening ,lung nodule ,pulmonary coccidioidomycosis ,valley fever ,Cancer ,Prevention ,Lung Cancer ,Biomedical Imaging ,Lung - Abstract
BackgroundCoccidioidomycosis (cocci) is an endemic fungal disease that can cause asymptomatic or post-symptomatic lung nodules which are visible on chest CT scanning. Lung nodules are common and can represent early lung cancer. Differentiating lung nodules due to cocci from those due to lung cancer can be difficult and lead to invasive and expensive evaluations.Materials and methodsWe identified 302 patients with biopsy-proven cocci or bronchogenic carcinoma seen in our multidisciplinary nodule clinic. Two experienced radiologists who were blinded to the diagnosis read the chest CT scans and identified radiographic characteristics to determine their utility in differentiating lung cancer nodules from those due to cocci.ResultsUsing univariate analysis, we identified several radiographic findings that differed between lung cancer and cocci infection. We then entered these variables along with age and gender into a multivariate model and found that age, nodule diameter, nodule cavitation, presence of satellite nodules and radiographic presence of chronic lung disease differed significantly between the two diagnoses. Three findings, cavitary nodules, satellite nodules and chronic lung disease, have sufficient discrimination to potentially be useful in clinical decision-making.ConclusionsCareful evaluation of the three obtained radiographic findings can significantly improve our ability to differentiate benign coccidioidomycosis infection from lung cancer in an endemic region for the fungal disease. Using these data may significantly reduce the cost and risk associated with distinguishing the cause of lung nodules in these patients by preventing unnecessary invasive studies.
- Published
- 2023
8. Association Between Shared Decision-Making During Family Meetings and Surrogates Trust in Their ICU Physician.
- Author
-
Lincoln, Taylor, Buddadhumaruk, Praewpannarai, Arnold, Robert, Scheunemann, Leslie, Ernecoff, Natalie, Chang, Chung-Chou, Carson, Shannon, Hough, Catherine, Curtis, J, Anderson, Wendy, Steingrub, Jay, Peterson, Michael, Lo, Bernard, Matthay, Michael, and White, Douglas
- Subjects
communication ,goals of care ,intensive care ,qualitative methods ,shared decision-making ,trust ,Humans ,Prospective Studies ,Trust ,Decision Making ,Intensive Care Units ,Physicians ,Family - Abstract
BACKGROUND: Although trust is central to successful physician-family relationships in ICUs, little is known about how to promote surrogates trust of ICU physicians in this setting. RESEARCH QUESTION: Does the conduct of family conferences and physicians use of shared decision-making (SDM) within family conferences impact surrogates trust in the physician? STUDY DESIGN AND METHODS: A mixed-methods secondary analysis was done of a multicenter prospective cohort study of 369 surrogate decision-makers of 204 decisionally incapacitated patients at high risk of death or severe functional impairment within 13 ICUs at six US medical centers between 2008 and 2012. Surrogates completed the Abbreviated Wake Forest Physician Trust Scale (range, 5-25) before and after an audio-recorded family conference conducted within 5 days of ICU admission. We qualitatively coded transcribed conferences to determine physicians use of five SDM behaviors: discussing surrogates role, explaining medical condition and prognosis, providing emotional support, assessing understanding, and eliciting patients values and preferences. Using multivariable linear regression with adjustment for clustering, we assessed whether surrogates trust in the physician increased after the family meeting; we also examined whether the number of SDM behaviors used by physicians during the family meeting impacted trust scores. RESULTS: In adjusted models, conduct of a family meeting was associated with increased trust (average change, pre- to post family meeting: 0.91 point [95% CI, 0.4-1.4; P < .01]). Every additional element of SDM used during the family meeting, including discussing surrogates role, providing emotional support, assessing understanding, and eliciting patients values and preferences, was associated with a 0.37-point increase in trust (95% CI, 0.08-0.67; P = .01). If all four elements were used, trust increased by 1.48 points. Explaining medical condition or prognosis was observed in nearly every conference (98.5%) and was excluded from the final model. INTERPRETATION: The conduct of family meetings and physicians use of SDM behaviors during meetings were both associated with increases in surrogates trust in the treating physician.
- Published
- 2023
9. Analysis of Air Pollution from Vehicle Emissions for the Contiguous United States
- Author
-
Filonchyk, Mikalai and Peterson, Michael P.
- Published
- 2024
- Full Text
- View/download PDF
10. Fractional quantum Hall effect at the filling factor $\nu=5/2$
- Author
-
Ma, Ken K. W., Peterson, Michael R., Scarola, V. W., and Yang, Kun
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Strongly Correlated Electrons - Abstract
The fractional quantum Hall (FQH) effect at the filling factor $\nu=5/2$ was discovered in GaAs heterostructures more than 35 years ago. Various topological orders have been proposed as possible candidates to describe this FQH state. Some of them possess non-Abelian anyon excitations, an entirely new type of quasiparticle with fascinating properties. If observed, non-Abelian anyons could offer fundamental building blocks of a topological quantum computer. Nevertheless, the nature of the FQH state at $\nu=5/2$ is still under debate. In this chapter, we provide an overview of the theoretical background, numerical results, and experimental measurements pertaining to this special FQH state. Furthermore, we review some recent developments and their possible interpretations. Possible future directions toward resolving the nature of the $5/2$ state are also discussed., Comment: Updated version; A chapter for Encyclopedia of Condensed Matter Physics, 2nd edition (Elsevier)
- Published
- 2022
- Full Text
- View/download PDF
11. The 2021 SIIM-FISABIO-RSNA Machine Learning COVID-19 Challenge: Annotation and Standard Exam Classification of COVID-19 Chest Radiographs.
- Author
-
Lakhani, Paras, Mongan, J, Singhal, C, Zhou, Q, Andriole, K, Auffermann, W, Prasanna, P, Pham, T, Peterson, Michael, Bergquist, P, Cook, T, Ferraciolli, S, Corradi, G, Takahashi, M, Workman, C, Parekh, M, Kamel, S, Galant, J, Mas-Sanchez, A, Benítez, E, Sánchez-Valverde, M, Jaques, L, Panadero, M, Vidal, M, Culiañez-Casas, M, Angulo-Gonzalez, D, Langer, S, de la Iglesia-Vayá, María, and Shih, G
- Subjects
Artificial Intelligence ,COVID-19 ,Machine Learning ,Pneumonia ,Radiography ,Thorax ,Humans ,COVID-19 ,Artificial Intelligence ,Radiography ,Machine Learning ,Radiologists ,Radiography ,Thoracic - Abstract
We describe the curation, annotation methodology, and characteristics of the dataset used in an artificial intelligence challenge for detection and localization of COVID-19 on chest radiographs. The chest radiographs were annotated by an international group of radiologists into four mutually exclusive categories, including typical, indeterminate, and atypical appearance for COVID-19, or negative for pneumonia, adapted from previously published guidelines, and bounding boxes were placed on airspace opacities. This dataset and respective annotations are available to researchers for academic and noncommercial use.
- Published
- 2023
12. Estimating air pollutant emissions from the 2024 wildfires in Canada and the impact on air quality
- Author
-
Filonchyk, Mikalai, Peterson, Michael P., Zhang, Liming, Zhang, Lifeng, and He, Yi
- Published
- 2025
- Full Text
- View/download PDF
13. Changes in aerosol properties at the El Arenosillo site in Southern Europe as a result of the 2023 Canadian forest fires
- Author
-
Filonchyk, Mikalai and Peterson, Michael P.
- Published
- 2024
- Full Text
- View/download PDF
14. Greenhouse gas emissions and reduction strategies for the world's largest greenhouse gas emitters
- Author
-
Filonchyk, Mikalai, Peterson, Michael P., Yan, Haowen, Gusev, Andrei, Zhang, Lifeng, He, Yi, and Yang, Shuwen
- Published
- 2024
- Full Text
- View/download PDF
15. Composite fermion mass enhancement and particle-hole symmetry of fractional quantum Hall states in the lowest Landau level under realistic conditions
- Author
-
Palacios, Eduardo and Peterson, Michael R.
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Particle-hole symmetry breaking in the fractional quantum Hall effect has recently been studied both theoretically and experimentally with most works focusing on non-Abelian states in the second electronic Landau level. In this work, we theoretically investigate particle-hole symmetry breaking of incompressible fractional quantum Hall states in the lowest Landau level under the influence of the realistic effect of a finite magnetic field strength. A finite magnetic field induces Landau level and sub-band mixing which are known to break particle-hole symmetry at the level of the Hamiltonian. We analyze the Haldane pseudopotentials, energy spectra and energy gaps, and the wave functions themselves, under realistic conditions. We find that particle-hole symmetry is broken, as determined by energy gaps, between states related via particle-hole conjugation, however, we find that particle-hole symmetry is largely maintained as determined by the effective mass of composite fermions. Finally, we comment and make connection to recent experimental observations regarding particle-hole symmetry in the lowest Landau level fractional quantum Hall effect [Pan et al. Phys. Rev. Lett. 124, 156801 (2020)], Comment: 9 pages, 8 figures, 4 tables
- Published
- 2021
- Full Text
- View/download PDF
16. Greenhouse gases emissions and global climate change: Examining the influence of CO2, CH4, and N2O
- Author
-
Filonchyk, Mikalai, Peterson, Michael P., Zhang, Lifeng, Hurynovich, Volha, and He, Yi
- Published
- 2024
- Full Text
- View/download PDF
17. An analysis of air pollution associated with the 2023 sand and dust storms over China: Aerosol properties and PM10 variability
- Author
-
Filonchyk, Mikalai, Peterson, Michael P., Zhang, Lifeng, and Yan, Haowen
- Published
- 2024
- Full Text
- View/download PDF
18. NO2 emissions from oil refineries in the Mississippi Delta
- Author
-
Filonchyk, Mikalai and Peterson, Michael P.
- Published
- 2023
- Full Text
- View/download PDF
19. Depression in Heart Failure: A Systematic Review.
- Author
-
Ishak, Waguih William, Edwards, Gabriel, Herrera, Nathalie, Lin, Tiffany, Hren, Kathryn, Peterson, Michael, Ngor, Ashley, Liu, Angela, Kimchi, Asher, Spiegel, Brennan, Hedrick, Rebecca, Chernoff, Robert, Diniz, Marcio, Mirocha, James, Manoukian, Vicki, Ong, Michael, Harold, John, Danovitch, Itai, and Hamilton, Michele
- Subjects
Health Services ,Heart Disease ,Cardiovascular ,Behavioral and Social Science ,Mental Health ,Brain Disorders ,Clinical Research ,Depression ,Mental health ,Adult attention-deficit/hyperactivity disorder ,comorbid disorders ,externalizing disorder ,internalizing disorder ,nosology - Abstract
Objective: This paper sought to identify the instruments used to measure depression in heart failure (HF) and elucidate the impact of treatment interventions on depression in HF. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed. Studies published from 1988 to 2018 covering depression and HF were identified through the review of the PubMed and PsycINFO databases using the keywords: "depres*" AND "heart failure." Two authors independently conducted a focused analysis, identifying 27 studies that met the specific selection criteria and passed the study quality checks. Results: Patient-reported questionnaires were more commonly adopted than clinician-rated questionnaires, including the Beck Depression Inventory, the Patient Health Questionnaire (PHQ-9), and the Hospital Anxiety and Depression Scale. Six common interventions were observed: antidepressant medications, collaborative care, psychotherapy, exercise, education, and other nonpharmacological interventions. Except for paroxetine, selective serotonin reuptake inhibitors failed to show a significant difference from placebo. However, the collaborative care model including the use of antidepressants showed a significant decrease in PHQ-9 score after one year. All of the psychotherapy studies included a variation of cognitive behavioral therapy and patients showed significant improvements. The evidence was mixed for exercise, education, and other nonpharmacological interventions. Conclusion: This study suggests which types of interventions are more effective in addressing depression in heart failure patients.
- Published
- 2020
20. An integrated analysis of air pollution from US coal-fired power plants
- Author
-
Filonchyk, Mikalai and Peterson, Michael P.
- Published
- 2023
- Full Text
- View/download PDF
21. A Particle-Hole-Symmetric Model for a Paired Fractional Quantum Hall State in a Half-filled Landau Level
- Author
-
Hutzel, William, McCord, John J., Raum, P. T., Stern, Ben, Wang, Hao, Scarola, V. W., and Peterson, Michael R.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
The fractional quantum Hall effect (FQHE) observed at half filling of the second Landau level is believed to be caused by a pairing of composite fermions captured by the Moore-Read Pfaffian wave function. The generating Hamiltonian for the Moore-Read Pfaffian is a purely three-body model that breaks particle-hole symmetry and lacks other properties, such as dominate two-body repulsive interactions, expected from a physical model of the FQHE. We use exact diagonalization to study the low energy states of a more physical two-body generator model derived from the three-body model. We find that the two-body model exhibits the essential features expected from the Moore-Read Pfaffian: pairing, non-Abelian anyon excitations, and a neutral fermion mode. The model also satisfies constraints expected for a physical model of the FQHE at half-filling because it is: short range, spatially decaying, particle-hole symmetric, and supports a roton mode with a robust spectral gap in the thermodynamic limit. Hence, this two-body model offers a bridge between artificial three-body generator models for paired states and the physical Coulomb interaction and can be used to further explore properties of non-Abelian physics in the FQHE., Comment: 11 pages, 11 figures, 3 appendices; Version 3 corrects a mislabeled Grant number in the Acknowledgments
- Published
- 2018
- Full Text
- View/download PDF
22. Cx3cr1-deficient microglia exhibit a premature aging transcriptome.
- Author
-
Gyoneva, Stefka, Hosur, Raghavendra, Gosselin, David, Zhang, Baohong, Ouyang, Zhengyu, Cotleur, Anne C, Peterson, Michael, Allaire, Norm, Challa, Ravi, Cullen, Patrick, Roberts, Chris, Miao, Kelly, Reynolds, Taylor L, Glass, Christopher K, Burkly, Linda, and Ransohoff, Richard M
- Subjects
Microglia ,Neurons ,Animals ,Mice ,Inbred C57BL ,Mice ,Transgenic ,Mice ,Knockout ,Mice ,Disease Models ,Animal ,Inflammation ,Aging ,Premature ,Lipopolysaccharides ,Receptors ,Chemokine ,Signal Transduction ,Gene Deletion ,Female ,Male ,Transcriptome ,CX3C Chemokine Receptor 1 ,Genetic Profile ,Inbred C57BL ,Transgenic ,Knockout ,Disease Models ,Animal ,Aging ,Premature ,Receptors ,Chemokine - Abstract
CX3CR1, one of the highest expressed genes in microglia in mice and humans, is implicated in numerous microglial functions. However, the molecular mechanisms underlying Cx3cr1 signaling are not well understood. Here, we analyzed transcriptomes of Cx3cr1-deficient microglia under varying conditions by RNA-sequencing (RNA-seq). In 2-mo-old mice, Cx3cr1 deletion resulted in the down-regulation of a subset of immune-related genes, without substantial epigenetic changes in markers of active chromatin. Surprisingly, Cx3cr1-deficient microglia from young mice exhibited a transcriptome consistent with that of aged Cx3cr1-sufficient animals, suggesting a premature aging transcriptomic signature. Immunohistochemical analysis of microglia in young and aged mice revealed that loss of Cx3cr1 modulates microglial morphology in a comparable fashion. Our results suggest that CX3CR1 may regulate microglial function in part by modulating the expression levels of a subset of inflammatory genes during chronological aging, making Cx3cr1-deficient mice useful for studying aged microglia.
- Published
- 2019
23. A Multicenter Study of the Causes and Consequences of Optimistic Expectations About Prognosis by Surrogate Decision-Makers in ICUs.
- Author
-
White, Douglas B, Carson, Shannon, Anderson, Wendy, Steingrub, Jay, Bird, Garrett, Curtis, J Randall, Matthay, Michael, Peterson, Michael, Buddadhumaruk, Praewpannarai, Shields, Anne-Marie, Ernecoff, Natalie, Shotsberger, Kaitlin, Weissfeld, Lisa, Chang, Chung-Chou H, Pike, Francis, Lo, Bernard, and Hough, Catherine L
- Subjects
Health Services and Systems ,Biomedical and Clinical Sciences ,Health Sciences ,Clinical Research ,Prevention ,Management of diseases and conditions ,7.3 Management and decision making ,APACHE ,Adult ,Aged ,Communication ,Decision Making ,Female ,Humans ,Intensive Care Units ,Length of Stay ,Male ,Middle Aged ,Optimism ,Physicians ,Professional-Family Relations ,Prognosis ,Prospective Studies ,Proxy ,Survival Analysis ,United States ,Withholding Treatment ,Clinical Sciences ,Nursing ,Public Health and Health Services ,Emergency & Critical Care Medicine ,Clinical sciences - Abstract
ObjectivesOptimistic expectations about prognosis by surrogate decision-makers in ICUs are common, but there are few data about the causes and clinical consequences. Our objective was to determine the causes of optimistic expectations about prognosis among surrogates and whether it is associated with more use of life support at the end of life.DesignProspective, multicenter cohort study from 2009 to 2012.SettingTwelve ICUs from multiple regions of the United States.SubjectsThe surrogates and physicians of 275 incapacitated ICU patients at high risk of death.InterventionsNone.Measurements and main resultsSurrogates and physicians completed a validated instrument assessing their prognostic expectations for hospital survival. We determined the proportion of surrogates with optimistic expectations, defined as a prognostic estimate that was at least 20% more optimistic than the physician's, then determined how frequently this arose from surrogates miscomprehending the physicians' prognosis versus holding more hopeful beliefs compared with the physician. We used multivariable regression to examine whether optimistic expectations were associated with length of stay, stratified by survival status, and time to withdrawal of life support among nonsurvivors. Overall, 45% of surrogates (95% CI, 38-51%) held optimistic expectations about prognosis, which arose from a combination of misunderstanding the physician's prognostic expectations and from holding more hopeful beliefs compared with the physician. Optimistic expectations by surrogates were associated with significantly longer duration of ICU treatment among nonsurvivors before death (β coefficient = 0.44; 95% CI, 0.05-0.83; p = 0.027), corresponding to a 56% longer ICU stay. This difference was associated with a significantly longer time to withdrawal of life support among dying patients whose surrogates had optimistic prognostic expectations compared with those who did not (β coefficient = 0.61; 95% CI, 0.16-1.07; p = 0.009).ConclusionsThe prevalent optimism about prognosis among surrogates in ICUs arises both from surrogates' miscomprehension of physicians' prognostications and from surrogates holding more hopeful beliefs. This optimism is associated with longer duration of life support at the end of life.
- Published
- 2019
24. The Rise of Valley Fever: Prevalence and Cost Burden of Coccidioidomycosis Infection in California
- Author
-
Wilson, Leslie, Ting, Jie, Lin, Harold, Shah, Rahil, MacLean, Michael, Peterson, Michael W, Stockamp, Nathan, Libke, Robert, and Brown, Paul
- Subjects
Infectious Diseases ,Comparative Effectiveness Research ,Burden of Illness ,Emerging Infectious Diseases ,2.4 Surveillance and distribution ,Aetiology ,Infection ,Good Health and Well Being ,California ,Coccidioidomycosis ,Cost of Illness ,Health Expenditures ,Humans ,Incidence ,Male ,Prevalence ,United States ,coccidioidomycosis ,cost-of-illness ,economic analysis ,Valley fever ,infection ,cost ,prevalence ,Toxicology - Abstract
Coccidioidomycosis (CM) is a fungal infection endemic in the southwestern United States (US). In California, CM incidence increased more than 213% (from 6.0/100,000 (2014) to 18.8/100,000 (2017)) and continues to increase as rates in the first half of 2018 are double that of 2017 during the same period. This cost-of-illness study provides essential information to be used in health planning and funding as CM infections continue to surge. We used a "bottom-up" approach to determine lifetime costs of 2017 reported incident CM cases in California. We defined CM natural history and used a societal approach to determine direct and discounted indirect costs using literature, national datasets, and expert interviews. The total lifetime cost burden of CM cases reported in 2017 in California is just under $700 million US dollars, with $429 million in direct costs and $271 million in indirect costs. Per person direct costs were highest for disseminated disease ($1,023,730), while per person direct costs were lowest for uncomplicated CM pneumonia ($22,039). Cost burden varied by county. This is the first study to estimate total costs of CM, demonstrating its huge cost burden for California.
- Published
- 2019
25. Measuring air pollution from the 2021 Canary Islands volcanic eruption
- Author
-
Filonchyk, Mikalai, Peterson, Michael P., Gusev, Andrei, Hu, Fengning, Yan, Haowen, and Zhou, Liang
- Published
- 2022
- Full Text
- View/download PDF
26. Performance analysis of paver blocks manufactured with an incorporation of waste from the disposable straw industry
- Author
-
de Oliveira, Elis Machado, Machado de Oliveira, Elen, de Oliveira, Camila Machado, Dal-Bó, Alexandre Gonçalves, and Peterson, Michael
- Published
- 2022
- Full Text
- View/download PDF
27. Deterioration of air quality associated with the 2020 US wildfires
- Author
-
Filonchyk, Mikalai, Peterson, Michael P., and Sun, Dongqi
- Published
- 2022
- Full Text
- View/download PDF
28. The enigmatic 12/5 fractional quantum Hall effect
- Author
-
Pakrouski, Kiryl, Troyer, Matthias, Wu, Yang-Le, Sarma, Sankar Das, and Peterson, Michael R.
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We numerically study the fractional quantum Hall effect at filling factors $\nu=12/5$ and 13/5 (the particle-hole conjugate of 12/5) in high-quality two-dimensional GaAs heterostructures via exact diagonalization including finite well width and Landau level mixing. We find that Landau level mixing suppresses $\nu=13/5$ fractional quantum Hall effect relative to $\nu=12/5$. By contrast, we find both $\nu=2/5$ and (its particle-hole conjugate) $\nu=3/5$ fractional quantum Hall effects in the lowest Landau level to be robust under Landau level mixing and finite well-width corrections. Our results provide a possible explanation for the experimental absence of the 13/5 fractional quantum Hall state as caused by Landau level mixing effects., Comment: 7 pages, 8 figures; v2 is published version
- Published
- 2016
- Full Text
- View/download PDF
29. Accuracy of magnitude- and complex-reconstruction chemical-shift-encoded magnetic resonance imaging proton density fat fraction for diagnosis of hepatic steatosis in subjects with severe obesity using histology as reference
- Author
-
Thai, Tydus T., Hamilton, Gavin, Covarrubias, Yesenia, Hooker, Jonathan C., Schlein, Alex N., Middleton, Michael S., Ballanay, Michelle L., Haufe, William M., Wiens, Curtis N., Artz, Nathan S., Funk, Luke M., McMillan, Alan, Agni, Rashmi, Peterson, Michael, Campos, Guilherme M., Greenberg, Jacob, Horgan, Santiago, Jacobson, Garth, Wolfson, Tanya, Gamst, Anthony, Schwimmer, Jeffrey, Reeder, Scott B., and Sirlin, Claude B.
- Abstract
To assess and compare the diagnostic performance of magnitude-reconstruction chemical-shift-encoded magnetic resonance imaging (MRI-M) and complex-reconstruction chemical-shift-encoded magnetic resonance imaging (MRI-C) for diagnosis of hepatic steatosis in subjects with severe obesity without known non-alcoholic fatty liver disease (NAFLD), using contemporaneous histology as reference. This is an IRB-approved, HIPAA-compliant, two-center, cross-sectional study of a larger prospective trail that recruited patients without known NAFLD consecutively between October 2010 and March 2015 to undergo research MRI exams 1-2 days prior to clinical-care weight-loss surgery. Proton denisty fat fraction (PDFF) was estimated using MRI-M and MRI-C. Liver biopsies were obtained intraoperatively. Using histologically-determined presence of steatosis as the reference standard, receiver operating characteristics (ROC) analyses were used to identify MRI-M- and MRI-C-derived PDFF thresholds for diagnosing steatosis. Bootstrapped-based tests were used to compare their diagnostic performace. A total of 81 patients (67 female, 14 maile, average age 48.2) were recruited for this study. MRI-M and MRI-C had areas under the ROC curve of 0.951 and 0.947, respectively, for diagnosing hepatic steatosis. for MRI-M, the Youden-index-based PDFF threshold of 6.5% provided 0.87 sensitivity (95% confidence internal: 0/75, 0.95), 0.96 specificity (0.81, 0.99), and 0.90 total accuracy (0.82, 0.96). For MRI-C, a PDFF threshold of 6.8%, provided a 0.90 sensitivity (0.77, 0.96), 0.96 specificity (0.81, 0.99), and 0.91 total accuracy (0.83, 0.97). Differences in performance parameters between MRI-M and MRI-C were not statistically significant. Conclusion: MRI-M- and MRI-C-derived PDFF is accurate for non-invasive diagnosis of hepatic steatosis in subjects with severe obesity.
- Published
- 2018
30. Highly efficient neuronal gene knockout in vivo by CRISPR-Cas9 via neonatal intracerebroventricular injection of AAV in mice
- Author
-
Hana, Sam, Peterson, Michael, McLaughlin, Helen, Marshall, Eric, Fabian, Attila J., McKissick, Olivia, Koszka, Kathryn, Marsh, Galina, Craft, Michael, Xu, Shanqin, Sorets, Alexander, Torregrosa, Tess, Sun, Chao, Henderson, Chris E., and Lo, Shih-Ching
- Published
- 2021
- Full Text
- View/download PDF
31. Landau level quantization for massless Dirac fermions in the spherical geometry: graphene fractional quantum Hall effect on the Haldane sphere
- Author
-
Arciniaga, Michael and Peterson, Michael R.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We derive the single-particle eigenenergies and eigenfunctions for massless Dirac fermions confined to the surface of a sphere in the presence of a magnetic monopole, i.e., we solve the Landau level problem for electrons in graphene on the Haldane sphere. With the single-particle eigenfunctions and eigenenergies we calculate the Haldane pseudopotentials for the Coulomb interaction in the second Landau level and calculate the effective pseudopotentials characterizing an effective Landau level mixing Hamiltonian entirely in the spherical geometry to be used in theoretical studies of the fractional quantum Hall effect in graphene. Our treatment is analogous to the formalism in the planar geometry and reduces to the planar results in the thermodynamic limit., Comment: 14 pages, 9 figures; v2 is published version with additional references and an additional section "Many-body exact diagonalization" with 2 new figures
- Published
- 2016
- Full Text
- View/download PDF
32. Abelian and Non-Abelian States in $\nu=2/3$ Bilayer Fractional Quantum Hall Systems
- Author
-
Peterson, Michael R., Wu, Yang-Le, Cheng, Meng, Barkeshli, Maissam, Wang, Zhenghan, and Sarma, Sankar Das
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
There are several possible theoretically allowed non-Abelian fractional quantum Hall (FQH) states that could potentially be realized in one- and two- component FQH systems at total filling fraction $\nu = n+ 2/3$, for integer $n$. Some of these states even possess quasiparticles with non-Abelian statistics that are powerful enough for universal topological quantum computation, and are thus of particular interest. Here, we initiate a systematic numerical study, using both exact diagonalization and variational Monte Carlo, to investigate the phase diagram of FQH systems at total filling fraction $\nu = n+2/3$, including in particular the possibility of the non-Abelian $Z_4$ parafermion state. In $\nu = 2/3$ bilayers, we determine the phase diagram as a function of interlayer tunneling and repulsion, finding only three competing Abelian states, without the $Z_4$ state. On the other hand, in single-component systems at $\nu = 8/3$, we find that the $Z_4$ parafermion state has significantly higher overlap with the exact ground state than the Laughlin state, together with a larger gap, suggesting that the experimentally observed $\nu = 8/3$ state may be non-Abelian. Our results from the two complementary numerical techniques agree well with each other qualitatively., Comment: 5 pages, 4 figures; v2 is the expanded published version with 7 pages, 6 figures, and additional references
- Published
- 2015
- Full Text
- View/download PDF
33. The Phase Diagram of the $\nu=5/2$ Fractional Quantum Hall Effect: Effects of Landau Level Mixing and Non-Zero Width
- Author
-
Pakrouski, Kiryl, Peterson, Michael R., Jolicoeur, Thierry, Scarola, Vito W., Nayak, Chetan, and Troyer, Matthias
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Interesting non-Abelian states, e.g., the Moore-Read Pfaffian and the anti-Pfaffian, offer candidate descriptions of the $\nu = 5/2$ fractional quantum Hall state. But the significant controversy surrounding the nature of the $\nu = 5/2$ state has been hampered by the fact that the competition between these and other states is affected by small parameter changes. To study the phase diagram of the $\nu = 5/2$ state we numerically diagonalize a comprehensive effective Hamiltonian describing the fractional quantum Hall effect of electrons under realistic conditions in GaAs semiconductors. The effective Hamiltonian takes Landau level mixing into account to lowest-order perturbatively in $\kappa$, the ratio of the Coulomb energy scale to the cyclotron gap. We also incorporate non-zero width $w$ of the quantum well and sub-band mixing. We find the ground state in both the torus and spherical geometries as a function of $\kappa$ and $w$. To sort out the non-trivial competition between candidate ground states we analyze the following 4 criteria: its overlap with trial wave functions; the magnitude of energy gaps; the sign of the expectation value of an order parameter for particle-hole symmetry breaking; and the entanglement spectrum. We conclude that the ground state is in the universality class of the Moore-Read Pfaffian state, rather than the anti-Pfaffian, for $\kappa < {\kappa_c}(w)$, where ${\kappa_c}(w)$ is a $w$-dependent critical value $0.6 \lesssim{\kappa_c}(w)\lesssim 1$. We observe that both Landau level mixing and non-zero width suppress the excitation gap, but Landau level mixing has a larger effect in this regard. Our findings have important implications for the identification of non-Abelian fractional quantum Hall states., Comment: 16 pages, 17 figures. Added: 1) Appendix D + Fig. 2 discussing planar vs spherical pseudopotentials and thermodynamic limit 2) Fig 8 showing topological gap 3) ancillary text files containing the numerical data for most of the figures
- Published
- 2014
- Full Text
- View/download PDF
34. Identifying topological order in the Shastry-Sutherland model via entanglement entropy
- Author
-
Ronquillo, David C. and Peterson, Michael R.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
It is known that for a topologically ordered state the area law for the entanglement entropy shows a negative universal additive constant contribution, $-\gamma$, called the topological entanglement entropy. We theoretically study the entanglement entropy of the two-dimensional Shastry-Sutherland quantum antiferromagnet using exact diagonalization on clusters of 16 and 24 spins. By utilizing the Kitaev-Preskill construction [A. Kitaev and J. Preskill, Phys. Rev. Lett. {\bf 96}, 110404 (2006)] we extract a finite topological term, $-\gamma$, in the region of bond-strength parameter space corresponding to high geometrical frustration. Thus, we provide strong evidence for the existence of an exotic topologically ordered state and shed light on the nature of this model's strongly frustrated, and long controversial, intermediate phase., Comment: 4 pages, 4 figures; v2 is published version with additional references
- Published
- 2014
- Full Text
- View/download PDF
35. The Effects of Landau level mixing on the fractional quantum Hall effect in monolayer Graphene
- Author
-
Peterson, Michael R. and Nayak, Chetan
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We report results of exact diagonalization studies of the spin- and valley-polarized fractional quantum Hall effect in the $N=0$ and 1 Landau levels in graphene. We use an effective model that incorporates Landau level mixing to lowest-order in the parameter $\kappa = \frac{e^2/\epsilon\ell}{\hbar v_F/\ell}=\frac{e^2}{\epsilon v_F\hbar}$ which is magnetic field independent and can only be varied through the choice of substrate. We find Landau level mixing effects are negligible in the $N=0$ Landau level for $\kappa\lesssim 2$. In fact, the lowest Landau level projected Coulomb Hamiltonian is a better approximation to the real Hamiltonian for graphene than it is for semiconductor based quantum wells. Consequently, the principal fractional quantum Hall states are expected in the $N=0$ Landau level over this range of $\kappa$. In the $N=1$ Landau level, fractional quantum Hall states are expected for a smaller range of $\kappa$ and Landau level mixing strongly breaks particle-hole symmetry producing qualitatively different results compared to the $N=0$ Landau level. At half-filling of the $N=1$ Landau level, we predict the anti-Pfaffian state will occur for $\kappa \sim 0.25$-$0.75$., Comment: 4 pages, 3 figures; v2 is published version with additional references
- Published
- 2014
- Full Text
- View/download PDF
36. Effects of partial sleep deprivation on slow waves during non-rapid eye movement sleep: A high density EEG investigation
- Author
-
Plante, David T, Goldstein, Michael R, Cook, Jesse D, Smith, Richard, Riedner, Brady A, Rumble, Meredith E, Jelenchick, Lauren, Roth, Andrea, Tononi, Giulio, Benca, Ruth M, and Peterson, Michael J
- Subjects
Medical Physiology ,Biomedical and Clinical Sciences ,Clinical Research ,Sleep Research ,Adolescent ,Adult ,Electroencephalography ,Female ,Humans ,Male ,Sleep ,Sleep Deprivation ,Sleep Stages ,Sleep ,REM ,Young Adult ,Electroencephalogram ,Sleep deprivation ,Sleep homeostasis ,Slow wave ,Synaptic plasticity ,Engineering ,Medical and Health Sciences ,Psychology and Cognitive Sciences ,Neurology & Neurosurgery ,Neurosciences - Abstract
ObjectiveChanges in slow waves during non-rapid eye movement (NREM) sleep in response to acute total sleep deprivation are well-established measures of sleep homeostasis. This investigation utilized high-density electroencephalography (hdEEG) to examine topographic changes in slow waves during repeated partial sleep deprivation.MethodsTwenty-four participants underwent a 6-day sleep restriction protocol. Spectral and period-amplitude analyses of sleep hdEEG data were used to examine changes in slow wave energy, count, amplitude, and slope relative to baseline.ResultsChanges in slow wave energy were dependent on the quantity of NREM sleep utilized for analysis, with widespread increases during sleep restriction and recovery when comparing data from the first portion of the sleep period, but restricted to recovery sleep if the entire sleep episode was considered. Period-amplitude analysis was less dependent on the quantity of NREM sleep utilized, and demonstrated topographic changes in the count, amplitude, and distribution of slow waves, with frontal increases in slow wave amplitude, numbers of high-amplitude waves, and amplitude/slopes of low amplitude waves resulting from partial sleep deprivation.ConclusionsTopographic changes in slow waves occur across the course of partial sleep restriction and recovery.SignificanceThese results demonstrate a homeostatic response to partial sleep loss in humans.
- Published
- 2016
37. Neural Correlates of Schizophrenia Negative Symptoms: Distinct Subtypes Impact Dissociable Brain Circuits.
- Author
-
Shaffer, Joseph J, Peterson, Michael J, McMahon, Mary Agnes, Bizzell, Joshua, Calhoun, Vince, van Erp, Theo GM, Ford, Judith M, Lauriello, John, Lim, Kelvin O, Manoach, Dara S, McEwen, Sarah C, Mathalon, Daniel H, O'Leary, Daniel, Potkin, Steven G, Preda, Adrian, Turner, Jessica, Voyvodic, Jim, Wible, Cynthia G, and Belger, Aysenil
- Subjects
Auditory oddball ,Functional Biomedical Informatics Research Network ,Functional magnetic resonance imaging ,Negative symptoms ,Schizophrenia ,Brain Disorders ,Behavioral and Social Science ,Clinical Research ,Neurosciences ,Mental Health ,Serious Mental Illness ,Underpinning research ,Aetiology ,2.1 Biological and endogenous factors ,1.1 Normal biological development and functioning ,Neurological ,Mental health - Abstract
BackgroundThe negative symptoms of schizophrenia include deficits in emotional expression and motivation. These deficits are stable over the course of illness and respond poorly to current medications. Previous studies have focused on negative symptoms as a single category; however, individual symptoms might be related to separate neurological disturbances. We analyzed data from the Functional Biomedical Informatics Research Network dataset to explore the relationship between individual negative symptoms and functional brain activity during an auditory oddball task.MethodsFunctional magnetic resonance imaging was conducted on 89 schizophrenia patients and 106 healthy controls during a two-tone auditory oddball task. Blood oxygenation level-dependent (BOLD) signal during the target tone was correlated with severity of five negative symptom domains from the Scale for the Assessment of Negative Symptoms.ResultsThe severity of alogia, avolition/apathy and anhedonia/asociality was negatively correlated with BOLD activity in distinct sets of brain regions associated with processing of the target tone, including basal ganglia, thalamus, insular cortex, prefrontal cortex, posterior cingulate and parietal cortex.ConclusionsIndividual symptoms were related to different patterns of functional activation during the oddball task, suggesting that individual symptoms might arise from distinct neural mechanisms. This work has potential to inform interventions that target these symptom-related neural disruptions.
- Published
- 2015
38. Deep-ocean foraging northern elephant seals bioaccumulate persistent organic pollutants
- Author
-
Peterson, Sarah H, Peterson, Michael G, Debier, Cathy, Covaci, Adrian, Dirtu, Alin C, Malarvannan, Govindan, Crocker, Daniel E, Schwarz, Lisa K, and Costa, Daniel P
- Subjects
Environmental Sciences ,Pollution and Contamination ,Adipose Tissue ,Animals ,Environmental Monitoring ,Female ,Food Chain ,Halogenated Diphenyl Ethers ,Hazardous Substances ,Male ,Pacific Ocean ,Polychlorinated Biphenyls ,Seals ,Earless ,Water Pollutants ,Chemical ,Pinniped ,Ecotoxicology ,Blubber burden ,Foraging ecology ,Mesopelagic ,Contaminants - Abstract
As top predators in the northeast Pacific Ocean, northern elephant seals (Mirounga angustirostris) are vulnerable to bioaccumulation of persistent organic pollutants (POPs). Our study examined a suite of POPs in blubber (inner and outer) and blood (serum) of free-ranging northern elephant seals. For adult females (N=24), we satellite tracked and sampled the same seals before and after their approximately seven month long foraging trip. For males, we sampled different adults and sub-adults before (N=14) and after (N=15) the same foraging trip. For females, we calculated blubber burdens for all compounds. The highest POP concentrations in males and females were found for ∑DDTs and ∑PCBs. In blubber and serum, males had significantly greater concentrations than females for almost all compounds. For males and females, ∑DDT and ∑PBDEs were highly correlated in blubber and serum. While ∑PCBs were highly correlated with ∑DDTs and ∑PBDEs in blubber and serum for males, ∑PCBs showed weaker correlations with both compounds in females. As females gained mass while foraging, concentrations of nearly all POPs in inner and outer blubber significantly decreased; however, the absolute burden in blubber significantly increased, indicating ingestion of contaminants while foraging. Additionally, we identified three clusters of seal foraging behavior, based on geography, diving behavior, and stable carbon and nitrogen isotopes, which corresponded with differences in ∑DDTs, ∑PBDEs, MeO-BDE 47, as well as the ratio of ∑DDTs to ∑PCBs, indicating the potential for behavior to heighten or mitigate contaminant exposure. The greatest concentrations of ∑DDTs and ∑PBDEs were observed in the cluster that foraged closer to the coast and had blood samples more enriched in (13)C. Bioaccumulation of POPs by elephant seals supports mesopelagic food webs as a sink for POPs and highlights elephant seals as a potential sentinel of contamination in deep ocean food webs.
- Published
- 2015
39. Diagnostic Accuracy of Preoperative Gadoxetic Acid–enhanced 3-T MR Imaging for Malignant Liver Lesions by Using Ex Vivo MR Imaging–matched Pathologic Findings as the Reference Standard
- Author
-
Costa, Eduardo AC, Cunha, Guilherme M, Smorodinsky, Emmanuil, Cruite, Irene, Tang, An, Marks, Robert M, Clark, Lisa, Wolfson, Tanya, Gamst, Anthony, Sicklick, Jason K, Hemming, Alan, Peterson, Michael R, Middleton, Michael S, and Sirlin, Claude B
- Subjects
Cancer ,Clinical Research ,Digestive Diseases ,Biomedical Imaging ,Detection ,screening and diagnosis ,4.2 Evaluation of markers and technologies ,Adult ,Aged ,Aged ,80 and over ,Contrast Media ,Cross-Sectional Studies ,Female ,Gadolinium DTPA ,Humans ,Liver Neoplasms ,Magnetic Resonance Imaging ,Male ,Middle Aged ,Predictive Value of Tests ,Preoperative Care ,Prospective Studies ,Reference Standards ,Reproducibility of Results ,Sensitivity and Specificity ,Young Adult ,Medical and Health Sciences ,Nuclear Medicine & Medical Imaging - Abstract
PurposeTo determine per-lesion sensitivity and positive predictive value (PPV) of gadoxetic acid-enhanced 3-T magnetic resonance (MR) imaging for the diagnosis of malignant lesions by using matched (spatially correlated) hepatectomy pathologic findings as the reference standard. Materials andMethodsIn this prospective, institutional review board-approved, HIPAA-compliant study, 20 patients (nine men, 11 women; mean age, 59 years) with malignant liver lesions who gave written informed consent underwent preoperative gadoxetic acid-enhanced 3-T MR imaging for surgical planning. Two image sets were independently analyzed by three readers to detect liver lesions (set 1 without and set 2 with hepatobiliary phase [HBP] images). Hepatectomy specimen ex vivo MR imaging assisted in matching gadoxetic acid-enhanced 3-T MR imaging findings with pathologic findings. Interreader agreement was assessed by using the Cohen κ coefficient. Per-lesion sensitivity and PPV were calculated.ResultsCohen κ values were 0.64-0.76 and 0.57-0.84, and overall per-lesion sensitivity was 45% (42 of 94 lesions) to 56% (53 of 94 lesions) and 58% (55 of 94 lesions) to 64% (60 of 94 lesions) for sets 1 and 2, respectively. The addition of HBP imaging did not affect interreader agreement but significantly improved overall sensitivity for one reader (P < .05) and almost for another (P = .05). Sensitivity for 0.2-0.5-cm lesions was 0% (0 of 26 lesions) to 8% (two of 26 lesions) for set 1 and 4% (one of 26 lesions) to 12% (three of 26 lesions) for set 2. Sensitivity for 0.6-1.0-cm lesions was 28% (nine of 32 lesions) to 59% (19 of 32 lesions) for set 1 and 66% (21 of 32 lesions) to 69% (22 of 32 lesions) for set 2. Sensitivity for lesions at least 1.0 cm in diameter was at least 81% (13 of 16 lesions) for set 1 and was not improved for set 2. PPV was 98% (56 of 57 lesions) to 100% (60 of 60 lesions) for all readers without differences between image sets or lesion size.ConclusionGadoxetic acid-enhanced 3-T MR imaging provides high per-lesion sensitivity and PPV for preoperative malignant liver lesion detection overall, although sensitivity for 0.2-0.5-cm malignant lesions is poor.
- Published
- 2015
40. Associations between histologic features of nonalcoholic fatty liver disease (NAFLD) and quantitative diffusion‐weighted MRI measurements in adults
- Author
-
Murphy, Paul, Hooker, Jonathan, Ang, Brandon, Wolfson, Tanya, Gamst, Anthony, Bydder, Mark, Middleton, Michael, Peterson, Michael, Behling, Cynthia, Loomba, Rohit, and Sirlin, Claude
- Subjects
Biomedical and Clinical Sciences ,Oncology and Carcinogenesis ,Liver Disease ,Chronic Liver Disease and Cirrhosis ,Biomedical Imaging ,Clinical Research ,Digestive Diseases ,Adult ,Aged ,Biopsy ,Cross-Sectional Studies ,Diffusion Magnetic Resonance Imaging ,Female ,Humans ,Image Interpretation ,Computer-Assisted ,Male ,Middle Aged ,Non-alcoholic Fatty Liver Disease ,Prospective Studies ,liver ,diffusion ,NAFLD ,NASH ,DWI ,IVIM ,Physical Sciences ,Engineering ,Medical and Health Sciences ,Nuclear Medicine & Medical Imaging ,Clinical sciences - Abstract
PurposeTo investigate in adults the associations between histologic features of nonalcoholic fatty liver disease (NAFLD) and quantitative measures derived from diffusion-weighted imaging (DWI).Materials and methodsEighty-nine adults undergoing standard-of-care liver biopsy for NAFLD were recruited for DWI. Biopsies were scored for histologic features of NAFLD. DWI was performed using b-values of 0, 100, and 500 s/mm(2) . Images were reconstructed using either conventional magnitude averaging (CMA) or a method to address bulk motion artifacts (Beta*LogNormal, BLN). The apparent diffusion coefficient (ADC) and the diffusivity (D) and perfusion fraction (F) of the intravoxel incoherent motion (IVIM) model were measured in the right hepatic lobe using both reconstructions. Associations between histologic features and DWI-derived measures were tested statistically with several methods including multiple linear regression.ResultsUsing CMA and BLN reconstructions, respectively, the means (and ranges) were 1.7 (1.1-3.5) and 1.4 (1.0-3.2) × 10(-3) mm(2) /s for ADC, 1.1 (0.84-1.4) and 0.84 (0.53-1.1) × 10(-3) mm(2) /s for D, and 17 and 18 (2.3-35)% for F. For both reconstruction methods, D decreased with steatosis and F decreased with fibrosis (P < 0.05). ADC was not independently associated with any histologic feature.ConclusionSteatosis and fibrosis have significant independent effects on D and F in adults undergoing biopsy for NAFLD.
- Published
- 2015
41. Immunodeficiency and Autoimmune Enterocolopathy Linked to NFAT5 Haploinsufficiency
- Author
-
Boland, Brigid S, Widjaja, Christella E, Banno, Asoka, Zhang, Bing, Kim, Stephanie H, Stoven, Samantha, Peterson, Michael R, Jones, Marilyn C, Su, H Irene, Crowe, Sheila E, Bui, Jack D, Ho, Samuel B, Okugawa, Yoshinaga, Goel, Ajay, Marietta, Eric V, Khosroheidari, Mahdieh, Jepsen, Kristen, Aramburu, Jose, López-Rodríguez, Cristina, Sandborn, William J, Murray, Joseph A, Harismendy, Olivier, and Chang, John T
- Subjects
Biomedical and Clinical Sciences ,Immunology ,Rare Diseases ,Health Disparities ,Genetics ,Pediatric ,Clinical Research ,Autoimmune Disease ,2.1 Biological and endogenous factors ,Inflammatory and immune system ,Animals ,Autoimmune Diseases ,CD8-Positive T-Lymphocytes ,Cells ,Cultured ,Cytokines ,DNA Mutational Analysis ,Gastrointestinal Diseases ,Gene Expression ,Haploinsufficiency ,Humans ,Immunoblotting ,Immunologic Deficiency Syndromes ,Jurkat Cells ,Killer Cells ,Natural ,Male ,Mice ,129 Strain ,Mice ,Knockout ,Reverse Transcriptase Polymerase Chain Reaction ,Transcription Factors ,Young Adult ,Biochemistry and cell biology - Abstract
The link between autoimmune diseases and primary immunodeficiency syndromes has been increasingly appreciated. Immunologic evaluation of a young man with autoimmune enterocolopathy and unexplained infections revealed evidence of immunodeficiency, including IgG subclass deficiency, impaired Ag-induced lymphocyte proliferation, reduced cytokine production by CD8(+) T lymphocytes, and decreased numbers of NK cells. Genetic evaluation identified haploinsufficiency of NFAT5, a transcription factor regulating immune cell function and cellular adaptation to hyperosmotic stress, as a possible cause of this syndrome. Inhibition or deletion of NFAT5 in normal human and murine cells recapitulated several of the immune deficits identified in the patient. These results provide evidence of a primary immunodeficiency disorder associated with organ-specific autoimmunity linked to NFAT5 deficiency.
- Published
- 2015
42. Development of a Real-Time PCR Assay for Identification of Coccidioides immitis by Use of the BD Max System
- Author
-
Mitchell, Marilyn, Dizon, Dominic, Libke, Robert, Peterson, Michael, Slater, David, and Dhillon, Akashdeep
- Subjects
Medical Microbiology ,Biomedical and Clinical Sciences ,Clinical Sciences ,Lung ,Biotechnology ,4.2 Evaluation of markers and technologies ,4.1 Discovery and preclinical testing of markers and technologies ,Body Fluids ,Coccidioides ,Coccidioidomycosis ,Humans ,Molecular Diagnostic Techniques ,Real-Time Polymerase Chain Reaction ,Sensitivity and Specificity ,Time Factors ,Biological Sciences ,Agricultural and Veterinary Sciences ,Medical and Health Sciences ,Microbiology ,Clinical sciences ,Medical microbiology - Abstract
Rapid real-time PCR (RT-PCR) can be performed in a community hospital setting to identify Coccidioides species using the new Becton Dickinson molecular instrument BD Max. Following sample preparation, DNA extraction and PCR were performed on the BD Max using the BD Max extraction kit ExK-DNA-1 test strip and a master mix prepared by BioGX (Birmingham, AL). Sample preparation took 2 h, and testing on the BD Max took an additional 2 h. Method sensitivity and specificity were evaluated along with the limits of detection to confirm that this convenient method would provide medically useful information. Using serial dilutions, the lower limit of detection was determined to be 1 CFU/μl. Testing with this method was validated using samples from various body sites, including bronchial alveolar lavage (BAL) fluid; sputum and lung tissue samples; and pleural and spinal fluids. Safety protocols were established, and specimen preparation processes were developed for the various types of specimens. The range for the cycle threshold (CT) indicating adequate fluorescent signal to signify a positive result was established along with the acceptable range for the internal standard. Positive controls run with each batch were prepared by spiking a pooled BAL fluid specimen with a known dilution of Coccidioides immitis organism. Our experience with testing >330 patient samples shows that clinically relevant information can be available within 4 h using an RT-PCR method on the BD Max to identify Coccidioides spp., with sensitivity equivalent to culture.
- Published
- 2015
43. Effect of Weight Loss on Magnetic Resonance Imaging Estimation of Liver Fat and Volume in Patients With Nonalcoholic Steatohepatitis
- Author
-
Patel, Niraj S, Doycheva, Iliana, Peterson, Michael R, Hooker, Jonathan, Kisselva, Tatiana, Schnabl, Bernd, Seki, Ekihiro, Sirlin, Claude B, and Loomba, Rohit
- Subjects
Biomedical and Clinical Sciences ,Clinical Sciences ,Nutrition ,Chronic Liver Disease and Cirrhosis ,Biomedical Imaging ,Liver Disease ,Hepatitis ,Digestive Diseases ,Obesity ,Clinical Research ,Oral and gastrointestinal ,Adult ,Aged ,Biopsy ,Body Mass Index ,Fats ,Female ,Histocytochemistry ,Humans ,Liver ,Magnetic Resonance Imaging ,Male ,Middle Aged ,Non-alcoholic Fatty Liver Disease ,Radiography ,Randomized Controlled Trials as Topic ,Weight Loss ,Noninvasive ,Steatosis ,Biomarker ,Response to Treatment ,Gastroenterology & Hepatology ,Clinical sciences - Abstract
Background & aimsLittle is known about how weight loss affects magnetic resonance imaging (MRI) of liver fat and volume or liver histology in patients with nonalcoholic steatohepatitis (NASH). We measured changes in liver fat and liver volume associated with weight loss by using an advanced MRI method.MethodsWe analyzed data collected from a previous randomized controlled trial in which 43 adult patients with biopsy-proven NASH underwent clinical evaluation, biochemical tests, and MRI and liver biopsy analyses at the start of the study and after 24 weeks. We compared data between patients who did and did not have at least 5% decrease in body mass index (BMI) during the study period.ResultsTen of 43 patients had at least a 5% decrease in BMI during the study period. These patients had a significant decrease in liver fat, which was based on MRI proton density fat fraction estimates (18.3% ± 7.6% to 13.6% ± 13.6%, P = .03), a relative 25.5% reduction. They also had a significant decrease in liver volume (5.3%). However, no significant changes in levels of alanine aminotransferase or aspartate aminotransferase were observed with weight loss. Thirty-three patients without at least 5% decrease in BMI had insignificant increases in estimated liver fat fraction and liver volume.ConclusionsA reduction in BMI of at least 5% is associated with significant decrease in liver fat and volume in patients with biopsy-proven NASH. These data should be considered in assessing effect size in studies of patients with nonalcoholic fatty liver disease or obesity that use MRI-estimated liver fat and volume as end points.
- Published
- 2015
44. Variational Monte Carlo study of spin polarization stability of fractional quantum Hall states against realistic effects in half-filled Landau levels
- Author
-
Biddle, J., Peterson, Michael R., and Sarma, S. Das
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We compare ground state energies by variational Monte Carlo of the spin unpolarized Halperin 331 and the spin polarized Moore-Read (MR) Pfaffian fractional quantum Hall states at half-filling of the lowest Landau level (LLL) and the second Landau level (SLL) as a function of small deviations around the Coulomb point via the finite thickness effect and direct alterations to the the first two Haldane pseudopotentials. In the comparison we find that in the LLL, either the 331 state or the MR Pfaffian may be lower in energy depending on the deviations. In the SLL, however, the MR Pfaffian is consistently lower in energy except for large deviations. These results suggest that even under moderate deviations in the interaction potential (through various physical processes such as finite thickness, Landau level mixing, etc.), the MR Pfaffian description is more energetically favorable than the Halperin 331 state in the half-filled SLL (i.e. $\nu = 5/2$), consistent with recent experimental investigations., Comment: 9 pages, 4 figures, 1 table
- Published
- 2013
- Full Text
- View/download PDF
45. More Realistic Hamiltonians for the Fractional Quantum Hall Regime in GaAs and Graphene
- Author
-
Peterson, Michael R. and Nayak, Chetan
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We construct an effective Hamiltonian for electrons in the fractional quantum Hall regime for GaAs and graphene that takes into account Landau level mixing (for both GaAs and graphene) and subband mixing (for GaAs, due to the nonzero width of the quantum well). This mixing has the important qualitative effect of breaking particle-hole symmetry as well as renormalizing the strength of the interparticle interactions. Both effects could have important consequences for the prospect that the fractional quantum Hall effect at $\nu=5/2$ is described by states that support non-Abelian excitations such as the Moore-Read Pfaffian or anti-Pfaffian states. For GaAs, Landau level and subband mixing break particle-hole symmetry in all Landau levels and subband mixing, due to finite thickness, causes additional short-distance softening of the Coulomb interaction, further renormalizing the Hamiltonian; additionally, the Landau level and subband energy spacings are comparable so it is crucial to consider both effects simultaneously. We find that in graphene, Landau level mixing only breaks particle-hole symmetry outside of the lowest Landau level ($N\neq0$). Landau level mixing is likely to be especially important in graphene since the Landau level mixing parameter is independent of the external magnetic field and is of order one. Our realistic Hamiltonians will serve as starting points for future numerical studies., Comment: 18 pages, 11 figures
- Published
- 2013
- Full Text
- View/download PDF
46. Entanglement Measures for Quasi-Two-Dimensional Fractional Quantum Hall States
- Author
-
Biddle, J., Peterson, Michael R., and Sarma, S. Das
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Quantum Physics - Abstract
We theoretically examine entanglement in fractional quantum hall states, explicitly taking into account and emphasizing the quasi-two-dimensional nature of experimental quantum Hall systems. In particular, we study the entanglement entropy and the entanglement spectrum as a function of the finite layer thickness $d$ of the quasi-two-dimensional system for a number of filling fractions $\nu$ in the lowest and the second Landau levels: $\nu$ = 1/3, 7/3, 1/2, and 5/2. We observe that the entanglement measures are dependent on which Landau level the electrons fractionally occupy, and find that filling factions 1/3 and 7/3, which are considered to be Laughlin states, weaken with $d$ in the lowest Landau level ($\nu$=1/3) and strengthen with $d$ in the second Landau level ($\nu$=7/3). For the enigmatic even-denominator $\nu=5/2$ state, we find that entanglement in the ground state is consistent with that of the non-Abelian Moore-Read Pfaffian state at an optimal thickness $d$. We also find that the single-layer $\nu = 1/2$ system is not a fractional quantum Hall state consistent with the experimental observation. In general, our theoretical findings based on entanglement considerations are completely consistent with the results based on wavefunction overlap calculations., Comment: 24 pages, 26 figures
- Published
- 2011
- Full Text
- View/download PDF
47. Towards Whole Schools: Building a Movement for Dialogue and Action in the 21st Century
- Author
-
Peterson, Michael
- Abstract
In this article, the author introduces whole schooling and its role within: to work towards positive change in schooling. The author discusses what led educators to the idea of creating schools that are more effective, engaging, and joyful places of growth and development for children.
- Published
- 2004
48. Analysis of the American Cancer Society's Generation Fit Project
- Author
-
Peterson, Michael, Goodwin, Steve, and Ellenberg, Deborah
- Abstract
This study examined the impact of the American Cancer Society's (ACS's) media based peer education program, Message Magic: Selling Healthy Eating and Physical Activity, on participant self-reported dietary and physical activity behaviors and advocacy skill development. High school students participating in the program were required to work as a team to examine advertising techniques and then develop a media-based message to be presented to peers. Results indicated that significant nutritional improvements in girls and physical activity improvements in boys were realized. The majority (76%) of participants expressed that their media messages had made a positive difference in their school and the program enhanced their advocacy skills. Students rated their experience in the program favorably. Findings suggest the ACS media-based program may be a viable option for a high school health curriculum. (Contains 3 tables.)
- Published
- 2004
49. Fractional quantum Hall effects in bilayers in the presence of inter-layer tunneling and charge imbalance
- Author
-
Peterson, Michael R., Papic, Z., and Sarma, S. Das
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Two-component fractional quantum Hall systems are providing a major motivation for a large section of the physics community. Here we study two-component fractional quantum Hall systems in the spin-polarized half-filled lowest Landau level (filling factor 1/2) and second Landau level (filling factor 5/2) with exact diagonalization utilizing both the spherical and torus geometries. The two distinct two-component systems we consider are the true bilayer and effective bilayers (wide-quantum-well). In each model (bilayer and wide-quantum-well) we completely take into account inter-layer tunneling and charge imbalancing terms. We find that in the half-filled lowest Landau level, the FQHE is described by the two-component Abelian Halperin 331 state which is remarkably robust to charge imbalancing. In the half-filled second Landau, we find that the FQHE is likely described by the non-Abelian Moore-Read Pfaffian state which is also quite robust to charge imbalancing. Furthermore, we suggest the possibility of experimentally tuning from an Abelian to non-Abelian FQHE state in the second Landau level, and comment on recent experimental studies of FQHE in wide quantum well structures., Comment: 25 pages, 27 figures
- Published
- 2010
- Full Text
- View/download PDF
50. Quantum Hall Phase Diagram of Half-filled Bilayers in the Lowest and the Second Orbital Landau Levels: Abelian versus Non-Abelian Incompressible Fractional Quantum Hall States
- Author
-
Peterson, Michael R. and Sarma, S. Das
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Strongly Correlated Electrons - Abstract
We examine the quantum phase diagram of the fractional quantum Hall effect (FQHE) in the lowest two Landau levels in half-filled bilayer structures as a function of tunneling strength and layer separation, i.e., we revisit the lowest Landau level filling factor 1/2 bilayer problem and make new predictions involving bilayers in the half-filled second Landau level (i.e., filling factor 5/2). Using numerical exact diagonalization we investigate the important question of whether this system supports a FQHE described by the non-Abelian Moore-Read Pfaffian state in the strong tunneling regime. In the lowest Landau level, we find that although in principle, increasing (decreasing) tunneling strength (layer separation) could lead to a transition from the Abelian two-component Halperin 331 to non-Abelian one-component Moore-Read Pfaffian state, the FQHE excitation gap is relatively small in the lowest Landau level Pfaffian regime--we establish that all so far observed FQHE states in half-filled lowest Landau level bilayers are most likely described by the Abelian Halperin 331 state. In the second Landau level we make the prediction that bilayer structures would manifest two distinct branches of incompressible FQHE corresponding to the Abelian 331 state (at moderate to low tunneling and large layer separation) and the non-Abelian Moore-Read Pfaffian state (at large tunneling and small layer separation). The observation of these two FQHE branches and the possible quantum phase transition between them will be compelling evidence supporting the existence of the non-Abelian Moore-Read Pfaffian state in the second Landau level. We discuss our results in the context of existing experiments and theoretical works., Comment: 23 pages, 18 figures. Updated version has fixed typos and updated and added reference.
- Published
- 2010
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.