22 results on '"Charles Fang"'
Search Results
2. Artificial Intelligence System for Automatic Quantitative Analysis and Radiology Reporting of Leg Length Radiographs
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Nathan Larson, Chantal Nguyen, Bao Do, Aryan Kaul, Anna Larson, Shannon Wang, Erin Wang, Eric Bultman, Kate Stevens, Jason Pai, Audrey Ha, Robert Boutin, Michael Fredericson, Long Do, and Charles Fang
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Radiography ,Leg ,Radiological and Ultrasound Technology ,Artificial Intelligence ,Humans ,Radiology, Nuclear Medicine and imaging ,Radiology ,Retrospective Studies ,Computer Science Applications - Abstract
Leg length discrepancies are common orthopedic problems with the potential for poor functional outcomes. These are frequently assessed using bilateral leg length radiographs. The objective was to determine whether an artificial intelligence (AI)-based image analysis system can accurately interpret long leg length radiographic images. We built an end-to-end system to analyze leg length radiographs and generate reports like radiologists, which involves measurement of lengths (femur, tibia, entire leg) and angles (mechanical axis and pelvic tilt), describes presence and location of orthopedic hardware, and reports laterality discrepancies. After IRB approval, a dataset of 1,726 extremities (863 images) from consecutive examinations at a tertiary referral center was retrospectively acquired and partitioned into train/validation and test sets. The training set was annotated and used to train a fasterRCNN-ResNet101 object detection convolutional neural network. A second-stage classifier using a EfficientNet-D0 model was trained to recognize the presence or absence of hardware within extracted joint image patches. The system was deployed in a custom web application that generated a preliminary radiology report. Performance of the system was evaluated using a holdout 220 image test set, annotated by 3 musculoskeletal fellowship trained radiologists. At the object detection level, the system demonstrated a recall of 0.98 and precision of 0.96 in detecting anatomic landmarks. Correlation coefficients between radiologist and AI-generated measurements for femur, tibia, and whole-leg lengths were 0.99, with mean error of 1%. Correlation coefficients for mechanical axis angle and pelvic tilt were 0.98 and 0.86, respectively, with mean absolute error of 1°. AI hardware detection demonstrated an accuracy of 99.8%. Automatic quantitative and qualitative analysis of leg length radiographs using deep learning is feasible and holds potential in improving radiologist workflow.
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- 2022
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3. Global Inclusive and Sustainable Competitive Industrial Performance (ISCIP): An efficiency based spatio-temporal analysis for 139 countries
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Charles Fang Chin Cheng, Qianqian Yuan, Cheng Hua, Yunqing Xu, Nicola Cantore, and Ke Wang
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General Energy ,Mechanical Engineering ,Building and Construction ,Management, Monitoring, Policy and Law - Published
- 2023
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4. Automatic Extraction of Skeletal Maturity from Whole Body Pediatric Scoliosis X-rays Using Regional Proposal and Compound Scaling Convolutional Neural Networks
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Bao Do, David B. Larson, Audrey Ha, Steve Dou, Charles Fang, Emily Wang, John S. Vorhies, Joanna Langner, Safwan Halabi, YongJin Lee, Andrew Campion, Japsimran Kaur, and Michael Fadell
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Orthodontics ,030222 orthopedics ,medicine.medical_specialty ,business.industry ,Intraclass correlation ,Bone age ,02 engineering and technology ,Scoliosis ,medicine.disease ,Surgical planning ,Convolutional neural network ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Orthopedic surgery ,0202 electrical engineering, electronic engineering, information engineering ,Medicine ,020201 artificial intelligence & image processing ,business ,Slipped capital femoral epiphysis ,Pelvis - Abstract
Skeletal maturity assessment plays an important role in the management of pediatric orthopedic conditions such as scoliosis, slipped capital femoral epiphysis (SCFE), and pectus. The most common methods to estimate bone age are the use of hand, shoulder, and pelvis x-rays; however, integrating multi-site data adds cost and ionizing radiation exposure. Whole body pediatric scoliosis x-rays, performed for measuring curvature of the spine, include in the field of view multiple development landmarks such as ossifications of the shoulder, pelvis, and proximal femurs in a single exam, potentially providing a comprehensive survey of skeletal maturity that can assist in surgical planning. Therefore, we propose a system to automatically extract multiple skeletal maturity classifications from a single whole body scoliosis x-ray exam. Since these anatomic regions of significance are as small as 2% of the image, we first apply a multi-class region proposal network to extract the humeral head and five pelvic regions based on the modified Oxford Bone Score. We then apply multiple compound scaling convolutional neural networks (EfficientNet) in parallel to clinically stage each region. Our regional detection achieved an F1-score of 0.99, and our staging models achieved an overall accuracy of 89% and intraclass correlation coefficient of 0.84. Our work holds promise for a skeletal maturity assessment system that uses a single image of the entire axial skeleton. This may enable more data points for surgical planning of orthopedic diseases in pediatric patients while minimizing exposure to harmful radiation.
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- 2020
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5. The Inclusive and Sustainable Development Index: a Data Envelopment Analysis Approach
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Nicola Cantore and Charles Fang Chin Cheng
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Sustainable development ,Industrialisation ,Ecological footprint ,Index (economics) ,Ranking ,Secondary sector of the economy ,Data envelopment analysis ,Regional science ,Economics ,Developing country - Abstract
Inclusive and Sustainable Industrial Development (ISID) calls for full engagement of policymakers in industrializing countries by minimizing environmental footprint and enhancing social inclusiveness. This study investigates the progress of 118 countries towards ISID (2005-2015) through an input-oriented CCR (Charnes, Cooper, and Rhodes) slack-based (Data Envelopment Analysis) DEA model. The efficiency analyses have been carried out with two approaches: i) the ISID approach represents the aspiration of countries to promote industrialization and consequently sustain economic growth by reducing the adverse environmental and social effects which manifest in the overall economy; ii) ISIDsdg9 approach considers the same aspects of ISID but only focuses on indicators related to the industrial sector. An analytical tool is developed to measure ISID with the two different approaches. This study finds that (i) Denmark, Sweden, and Switzerland are at the top of the ranking with the ISID approach, and the Czech Republic and Switzerland are at the top of the ranking with the ISIDsdg9 approach. Throughout 2005-2013, there is no sign of catching up between developed and developing countries in progress towards ISID and ISIDsdg9.
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- 2020
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6. The Inclusive and Sustainable Development Index: a Data Envelopment Analysis Approach
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Cheng, Charles Fang Chin and Cantore, Nicola
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Slack-Based Model (SBM) ,Inclusive and Sustainable Industrial Development (ISID) Data Envelopment Analysis (DEA) ,United Nations Sustainable Development Goals (UN SDGs) ,Environmental Economics and Policy - Abstract
Inclusive and Sustainable Industrial Development (ISID) calls for full engagement of policymakers in industrializing countries by minimizing environmental footprint and enhancing social inclusiveness. This study investigates the progress of 118 countries towards ISID (2005-2015) through an input-oriented CCR (Charnes, Cooper, and Rhodes) slack-based (Data Envelopment Analysis) DEA model. The efficiency analyses have been carried out with two approaches: i) the ISID approach represents the aspiration of countries to promote industrialization and consequently sustain economic growth by reducing the adverse environmental and social effects which manifest in the overall economy; ii) ISIDsdg9 approach considers the same aspects of ISID but only focuses on indicators related to the industrial sector. An analytical tool is developed to measure ISID with the two different approaches. This study finds that (i) Denmark, Sweden, and Switzerland are at the top of the ranking with the ISID approach, and the Czech Republic and Switzerland are at the top of the ranking with the ISIDsdg9 approach. Throughout 2005-2013, there is no sign of catching up between developed and developing countries in progress towards ISID and ISIDsdg9.
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- 2020
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7. The Inclusive and Sustainable Development Index: a Data Envelopment Analysis Approach
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Cheng, Charles Fang Chin and Cantore, Nicola
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Data Envelopment Analysis (DEA) ,Q54 ,Slack-Based Model (SBM) ,ddc:330 ,United Nations Sustainable Development Goals (UN SDGs) ,Q01 ,Inclusive and Sustainable Industrial Development (ISID) - Abstract
Inclusive and Sustainable Industrial Development (ISID) calls for full engagement of policymakers in industrializing countries by minimizing environmental footprint and enhancing social inclusiveness. This study investigates the progress of 118 countries towards ISID (2005-2015) through an input-oriented CCR (Charnes, Cooper, and Rhodes) slack-based (Data Envelopment Analysis) DEA model. The efficiency analyses have been carried out with two approaches: i) the ISID approach represents the aspiration of countries to promote industrialization and consequently sustain economic growth by reducing the adverse environmental and social effects which manifest in the overall economy; ii) ISIDsdg9 approach considers the same aspects of ISID but only focuses on indicators related to the industrial sector. An analytical tool is developed to measure ISID with the two different approaches. This study finds that (i) Denmark, Sweden, and Switzerland are at the top of the ranking with the ISID approach, and the Czech Republic and Switzerland are at the top of the ranking with the ISIDsdg9 approach. Throughout 2005-2013, there is no sign of catching up between developed and developing countries in progress towards ISID and ISIDsdg9.
- Published
- 2020
8. International trade of environmental goods in gravity models
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Nicola Cantore and Charles Fang Chin Cheng
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Sustainable development ,Conservation of Natural Resources ,Gravity (chemistry) ,Environmental Engineering ,business.industry ,020209 energy ,Developing country ,02 engineering and technology ,General Medicine ,International trade ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,01 natural sciences ,Gravity model of trade ,Income ,0202 electrical engineering, electronic engineering, information engineering ,Industry ,Production (economics) ,Environmental regulation ,Substitution effect ,Literature study ,business ,Developing Countries ,Waste Management and Disposal ,0105 earth and related environmental sciences - Abstract
Environmental goods are goods used or produced by industry that reduce air and water pollution and optimize the use of resources in production. Despite several Sustainable Development Goals explicitly calling for resilient and sustainable development, the diffusion of such goods is still low, especially in developing countries. Only sporadic research on the determinants of international trade of environmental goods is available. Based on the OECD classification of environmental goods, this gap is filled by adopting a gravity model, using trade data over a time span of 15 years from 1999 to 2014 across 71 countries. The central message of this paper is that environmental regulatory stringency is a key determinant of environmental goods trade. It is specifically provided evidence that a substitution effect exists between environmental regulation stringency and trade of environmental goods. In line with empirical literature on traditional gravity models, increased capacity to innovate, cultural ties, geographical proximity and financial uncertainty also play a role.
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- 2018
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9. Developing pro-environmental behaviour: ecotourism fieldtrip and experiences
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Charles Fang Chin Cheng and Ding Hooi Ting
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Value (ethics) ,Guiding Principles ,Higher education ,business.industry ,05 social sciences ,Behavior change ,Applied psychology ,050301 education ,050109 social psychology ,Human Factors and Ergonomics ,Experiential learning ,Focus group ,Education ,Ecotourism ,Pedagogy ,Normative ,0501 psychology and cognitive sciences ,Psychology ,business ,0503 education - Abstract
PurposeThis study aims to assess the effectiveness of a student participatory approach and assessment to achieve an environmentally friendly behaviour and change strategy.Design/methodology/approachThree time-phase studies employed a participatory and experiential case in the form of ecotourism experiential learning and assessment using a sample of 100 higher education students.FindingsThe findings suggest that students’ participations through the development, implementation and maintenance of nature-based experiences, combined with professional guides in educating students about sustainable practices has significant and positive effects on pro-environmental behaviour (PEB). The study reveals that social-psychological constructs (except environmental awareness) and socio-demographic variables account for variances in PEB intentions and provides managerial implications for marketers on the use of student participation to enhance behaviour.Practical implicationsExperiential and guided learning adds value to PEB through performance accomplishments and instrumental support.Social implicationsThe guiding principles of moral norms and acting in favour of the community (general social pressure and the underlying normative beliefs) lead to a higher tendency to perform according to the ideal behaviour.Originality/valueThis study is the first to use student participation, guided learning, tour guides and experiences to transfer the knowledge of PEB to individuals.
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- 2017
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10. Measuring the marginal effect of pro-environmental behaviour: Guided learning and behavioural enhancement
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Ding Hooi Ting and Charles Fang Chin Cheng
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Positive education ,education ,05 social sciences ,050301 education ,050109 social psychology ,Citizen journalism ,Ordered probit ,Outcome (game theory) ,Education ,Ecotourism ,Tourism, Leisure and Hospitality Management ,Sustainability ,ComputingMilieux_COMPUTERSANDEDUCATION ,Mathematics education ,Position (finance) ,0501 psychology and cognitive sciences ,Psychology ,0503 education ,Curriculum ,Social psychology - Abstract
This paper aims to examine the pro-environmental behaviour (PEB) outcome and change through student participation and guided learning in an ecotourism-education-based study setting. The authors collected responses from 100 students who visited ecotourism sites as part of their learning curriculum at the end of a semester. The ordered probit model was employed to predict the variables under study. The findings suggest that students’ participations, coupled with professional guides, has significant and positive effects on PEB. The findings have the potential to position participatory and guided learning as effective solutions in promoting positive education outcome among individuals.
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- 2017
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11. The Importance of Manufacturing in Economic Development: Has This Changed?
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Eveline Smeets, Nobuya Haraguchi, and Charles Fang Chin Cheng
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Deindustrialization ,Economics and Econometrics ,Manufacturing employment ,Economic growth ,Sociology and Political Science ,020209 energy ,Geography, Planning and Development ,Developing country ,02 engineering and technology ,Development ,Backwardness ,Manufacturing sector ,Mature stage ,Industrialisation ,Value (economics) ,0202 electrical engineering, electronic engineering, information engineering ,Economics - Abstract
Summary Manufacturing has traditionally played a key role in the economic development of developing countries. In recent years, it has been argued that the importance of manufacturing has diminished over the last 20–25 years, resulting in premature deindustrialization or non-industrialization in developing countries. This study explores whether the low levels of industrialization in developing countries are attributable to long-term changes in opportunities available to the sector around the globe. The study’s findings show that the manufacturing sector’s value added and employment contribution to world GDP and employment, respectively, have not changed significantly since 1970. The declining manufacturing value added and manufacturing employment share in many developing countries has not been caused by changes in the sector’s development potential but has instead resulted from a shift of manufacturing activities to a relatively small number of populous countries, thus resulting in a concentration of manufacturing activities in specific developing countries. As was the case in the last millennium, industrialization has continued to play a key role in the growth of developing countries, which have sustained rapid and long-term growth for the last 25 years. Achieving economic development by following the path of industrialization will likely remain important for low-income countries because they are able to take advantage of their backwardness relative to those countries which have already experienced rapid industrialization with a disproportionately large share of manufacturing activities, and could soon enter a mature stage of industrialization.
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- 2017
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12. Switching it up: The effect of energy price reforms in Oman
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Massimiliano Calì, Charles Fang Chin Cheng, Valentin Todorov, Nicola Cantore, and Juergen Amann
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Economics and Econometrics ,Sociology and Political Science ,Transparency (market) ,business.industry ,050204 development studies ,05 social sciences ,Geography, Planning and Development ,Factor price ,Public debate ,Subsidy ,Energy consumption ,Development ,Manufacturing ,0502 economics and business ,Economics ,050207 economics ,business ,Productivity ,Industrial organization ,Externality - Abstract
For the most part the public debate on fossil fuel energy subsidies has been governed by two arguments. From the position of the profit-maximizing firm, the economic rationale has gravitated towards the issue of cost-competitiveness: The reduction of emissions requires a cutback of energy consumption which, when operating through the pricing mechanism, drives up the cost of inputs; increases in fossil fuel prices may therefore harm competitiveness. On the other hand, the environmental argument stresses the importance of cost transparency and externalities. However, there has also emerged a body of research which introduces a second layer to the argument of cost-competitiveness by emphazising that an increase in energy prices may not necessarily be detrimental to economic performance. This study provides novel evidence on this insight by examining the effect of a change in fossil fuel subsidies on the manufacturing industry of an oil-rich Middle Eastern economy. Using a novel firm-level micro data set on Omani manufacturing enterprises, our work shows that increases in fossil fuel energy factor prices lead to improvements in productivity as well as efficiency and notable business upgrading. The findings in this paper indicate that subsidy reforms may not only be used to achieve environmental goals but may also drive upgrading and modernization processes of firms that can, ultimately, also improve economic performance.
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- 2021
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13. Study on the leachable behavior of cation exchange resins
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Tung-Jen Wen, Charles-Fang Chu, Dah-Yu Kao, and Liang-Cheng Chen
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Total organic carbon ,Nuclear and High Energy Physics ,Chromatography ,Ion exchange ,Chemistry ,technology, industry, and agriculture ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Gel permeation chromatography ,chemistry.chemical_compound ,020401 chemical engineering ,Nuclear Energy and Engineering ,Environmental chemistry ,Water chemistry ,Leachate ,0204 chemical engineering ,Sulfate ,0210 nano-technology - Abstract
The amount of total organic carbon (TOC) leached from cation exchange resins (CERs) in condensate demineralizers are related to the quality of reactor water in nuclear power plants (NPPs). In the recent years, quality problems of CERs used by ChinShan and KuoSheng NPPs have been identified. Prior to use, TOC and sulfate concentrations must be reduced to meet the criteria; however, this involves an extended purification process and heavy use of water resources. Even in cases where resin can be used, the quality of the water in the reactor remains poor. This study, therefore, investigated the leachates of resins from these NPPs in order to establish a reference for the quality of deep bed CERs. Gel permeation chromatography and ion-pair chromatography were used to identify molecular peaks in the CER leachates in order to elucidate the molecular distributions. We also sought to determine TOC and sulfate concentrations of post-UV treatment using long-term soaking tests, in which the solutions used to soak res...
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- 2015
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14. Comparative analyses of clinical and environmental populations of Cryptococcus neoformans in Botswana
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Charles Muthoga, Miriam Haverkamp, Thomas G. Mitchell, Aubrey E. Frazzitta, John R. Perfect, Anastasia P. Litvintseva, Liuyang Wang, Charles Fang, and Yuan Chen
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Molecular Sequence Data ,Zoology ,Environment ,Population and Conservation Genetics ,Trees ,Genetic variation ,Genotype ,Genetics ,medicine ,Humans ,Allele ,DNA, Fungal ,Genotyping ,Ecology, Evolution, Behavior and Systematics ,Alleles ,Cryptococcus neoformans ,Genetic diversity ,Botswana ,biology ,Geography ,fungi ,Genetic Variation ,population structure ,Cryptococcosis ,Sequence Analysis, DNA ,biology.organism_classification ,medicine.disease ,Genes, Mating Type, Fungal ,recombination ,Genetics, Population ,genotyping ,Multilocus sequence typing ,Original Article ,ORIGINAL ARTICLES ,Multilocus Sequence Typing - Abstract
Cryptococcus neoformans var. grubii (Cng) is the most common cause of fungal meningitis, and its prevalence is highest in sub‐Saharan Africa. Patients become infected by inhaling airborne spores or desiccated yeast cells from the environment, where the fungus thrives in avian droppings, trees and soil. To investigate the prevalence and population structure of Cng in southern Africa, we analysed isolates from 77 environmental samples and 64 patients. We detected significant genetic diversity among isolates and strong evidence of geographic structure at the local level. High proportions of isolates with the rare MATa allele were observed in both clinical and environmental isolates; however, the mating‐type alleles were unevenly distributed among different subpopulations. Nearly equal proportions of the MATa and MATα mating types were observed among all clinical isolates and in one environmental subpopulation from the eastern part of Botswana. As previously reported, there was evidence of both clonality and recombination in different geographic areas. These results provide a foundation for subsequent genomewide association studies to identify genes and genotypes linked to pathogenicity in humans.
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- 2015
15. Next generation multilocus sequence typing (NGMLST) and the analytical software program MLSTEZ enable efficient, cost-effective, high-throughput, multilocus sequencing typing
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John R. Perfect, Anastasia P. Litvintseva, Thomas G. Mitchell, Yun Ding, Charles Fang, Deborah J. Springer, Yuan Chen, George Yuan, and Aubrey E. Frazzitta
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Genotype ,Cost-Benefit Analysis ,Biology ,Polymerase Chain Reaction ,Microbiology ,Article ,Genetics ,PacBio CCS sequencing ,Humans ,Typing ,Clade ,Genotyping ,Phylogeny ,Whole genome sequencing ,Phylogenetic tree ,High-Throughput Nucleotide Sequencing ,Multiplex PCR ,Amplicon ,bacterial infections and mycoses ,genomic DNA ,Next generation sequencing (NGS) ,Cryptococcus neoformans ,Multilocus sequence typing ,Software ,MLST ,Multilocus Sequence Typing - Abstract
Multilocus sequence typing (MLST) has become the preferred method for genotyping many biological species, and it is especially useful for analyzing haploid eukaryotes. MLST is rigorous, reproducible, and informative, and MLST genotyping has been shown to identify major phylogenetic clades, molecular groups, or subpopulations of a species, as well as individual strains or clones. MLST molecular types often correlate with important phenotypes. Conventional MLST involves the extraction of genomic DNA and the amplification by PCR of several conserved, unlinked gene sequences from a sample of isolates of the taxon under investigation. In some cases, as few as three loci are sufficient to yield definitive results. The amplicons are sequenced, aligned, and compared by phylogenetic methods to distinguish statistically significant differences among individuals and clades. Although MLST is simpler, faster, and less expensive than whole genome sequencing, it is more costly and time-consuming than less reliable genotyping methods (e.g. amplified fragment length polymorphisms). Here, we describe a new MLST method that uses next-generation sequencing, a multiplexing protocol, and appropriate analytical software to provide accurate, rapid, and economical MLST genotyping of 96 or more isolates in single assay. We demonstrate this methodology by genotyping isolates of the well-characterized, human pathogenic yeast Cryptococcus neoformans.
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- 2015
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16. Jejunal arterial access for retrograde mesenteric stenting
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Uttara Nag, Mitchell W. Cox, Ryan S. Turley, Richard L. McCann, Brian F. Gilmore, Megan C. Turner, and Charles Fang
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medicine.medical_specialty ,medicine.medical_treatment ,Population ,Arteriotomy ,Dissection (medical) ,Punctures ,030204 cardiovascular system & hematology ,030230 surgery ,03 medical and health sciences ,0302 clinical medicine ,Mesenteric Artery, Superior ,Laparotomy ,medicine.artery ,Mesenteric Vascular Occlusion ,medicine ,Humans ,Superior mesenteric artery ,Splanchnic Circulation ,education ,Vascular Patency ,Aged ,Aged, 80 and over ,education.field_of_study ,business.industry ,Endovascular Procedures ,Angiography ,Limiting ,Middle Aged ,medicine.disease ,Surgery ,Jejunum ,Treatment Outcome ,Mesenteric ischemia ,Mesenteric Ischemia ,Stents ,Cardiology and Cardiovascular Medicine ,business ,Surgical revascularization - Abstract
Endovascular approaches have replaced open surgical revascularization in most patients with mesenteric ischemia; however, flush ostial occlusions may not be amenable to traditional antegrade access. Retrograde mesenteric stenting has been previously described, but this technique requires a formal laparotomy and dissection of the proximal superior mesenteric artery. We present here a modification of this technique that requires only a "mini-laparotomy" and no open vascular repair of the superior mesenteric artery as well as a review of our initial institutional experience with this procedure. Our approach differs from previously described work by minimizing mesenteric dissection, avoiding the need for repair of an arteriotomy, and limiting the size of the laparotomy incision in this population of profoundly comorbid patients.
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- 2017
17. Immediate Access Arteriovenous Grafts Decrease Catheter Days and Complications
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Ellen D. Dillavou, Uttara Nag, Efthimios D. Avgerinos, Jason K. Wagner, Kavi Devulapalli, Charles Fang, and Mitchell W. Cox
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medicine.medical_specialty ,Catheter ,business.industry ,Medicine ,Surgery ,Arteriovenous grafts ,Cardiology and Cardiovascular Medicine ,business - Published
- 2019
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18. IP159. Use of Hemodialysis Reliable Outflow (HeRO) With Immediate Access Arteriovenous Grafts
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Jason K. Wagner, Megan C. Turner, Uttara Nag, Efthymios D. Avgerinos, Mitchell W. Cox, Charles Fang, Kavi Devulapalli, and Ellen D. Dillavou
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medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,medicine ,HERO ,Surgery ,Outflow ,Hemodialysis ,Arteriovenous grafts ,Cardiology and Cardiovascular Medicine ,business - Published
- 2017
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19. Evaluation of correction methods for coil-induced intensity inhomogeneities and their influence on trabecular bone structure parameters from MR images
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Janet Goldenstein, Thomas M. Link, Charles Fang, Sharmila Majumdar, Roland Krug, Ahi Sema Issever, and Jenny Folkesson
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Reproducibility ,Materials science ,medicine.diagnostic_test ,business.industry ,Osteoporosis ,Biomechanics ,Magnetic resonance imaging ,General Medicine ,medicine.disease ,Intensity (physics) ,Trabecular bone ,Electromagnetic coil ,medicine ,Medical imaging ,Nuclear medicine ,business ,Biomedical engineering - Abstract
Magnetic resonance(MR)imaging-based quantitative trabecular bone structure analysis has gained increasing interest in osteoporotic fracture risk assessment and treatment evaluation related to osteoporosis. In vivoMRimages of anatomic regions such as the proximal femur and distal tibia are generally acquired with a surface coil in order to obtain sufficient sensitivity and resolution for quantification of the trabeculae. However, these coils introduce intensity inhomogeneities which affect the trabecular bone structure analysis. This work evaluates the applicability of a fully automatic coil correction by nonparametric nonuniform intensity normalization (N3) in the analysis of trabecular bone parameters. The ability to correct for coil-induced intensity inhomogeneity was evaluated ex vivo on proximal femur specimens scanned with both a surface coil and a volume coil, which allowed for a direct evaluation of the performance of the coil correction methods without any major confounding factors. In addition, trabecular bone parameter values were correlated with values from high-resolution peripheral computed tomography (HR-pQCT) scans, and the reproducibility of trabecular bone parameters was evaluated in an in vivo study of repeat hip MR scans. The trabecular bone parameters determined from MRsurface coil scans processed with the N3 coil correction method showed significant correlation ( p 0.05 ) with corresponding values from homogeneous intensity data in the ex vivo study. This can be compared to the correlation without coil correction ( p 0.5 ) , and coil correction using low-pass filtering (LPF) ( p 0.53 ) . The in vivo interscan variability was reduced from 8.9% to 12.8% using LPF-based to 3.6%–8.4% (CV) using N3 coil correction; hence the results showed that N3 is advantageous to LPF-based coil correction. No significant differences in correlation to HR-pQCT data were found for the coil correction methods. The significant correlations with volume coil data and high reproducibility of the N3 processed data imply that N3 coil correction preserve image information while accurately correcting for coil-induced intensity inhomogeneities, which makes it suitable for quantitative analysis of trabecular bone structure from MRimages acquired with surface coils.
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- 2009
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20. The Cryptococcus neoformans transcriptome at the site of human meningitis
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Thomas G. Mitchell, Dena L. Toffaletti, Jennifer L. Tenor, David R. Boulware, Tihana Bicanic, Charles Fang, Yuan Chen, Tami R. McDonald, Kirsten Nielsen, John R. Perfect, and Anastasia P. Litvintseva
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Fungal meningitis ,HIV Infections ,Meningitis, Cryptococcal ,Biology ,Microbiology ,Transcriptome ,In vivo ,Gene Expression Regulation, Fungal ,Virology ,medicine ,Humans ,Gene ,Cerebrospinal Fluid ,Cryptococcus neoformans ,Gene Expression Profiling ,Fungal genetics ,High-Throughput Nucleotide Sequencing ,RNA, Fungal ,medicine.disease ,biology.organism_classification ,QR1-502 ,Gene expression profiling ,Ex vivo ,Research Article - Abstract
Cryptococcus neoformans is the leading cause of fungal meningitis worldwide. Previous studies have characterized the cryptococcal transcriptome under various stress conditions, but a comprehensive profile of the C. neoformans transcriptome in the human host has not been attempted. Here, we extracted RNA from yeast cells taken directly from the cerebrospinal fluid (CSF) of two AIDS patients with cryptococcal meningitis prior to antifungal therapy. The patients were infected with strains of C. neoformans var. grubii of molecular type VNI and VNII. Using RNA-seq, we compared the transcriptional profiles of these strains under three environmental conditions (in vivo CSF, ex vivo CSF, and yeast extract-peptone-dextrose [YPD]). Although we identified a number of differentially expressed genes, single nucleotide variants, and novel genes that were unique to each strain, the overall expression patterns of the two strains were similar under the same environmental conditions. Specifically, yeast cells obtained directly from each patient’s CSF were more metabolically active than cells that were incubated ex vivo in CSF. Compared with growth in YPD, some genes were identified as significantly upregulated in both in vivo and ex vivo CSF, and they were associated with genes previously recognized for contributing to pathogenicity. For example, genes with known stress response functions, such as RIM101, ENA1, and CFO1, were regulated similarly in the two clinical strains. Conversely, many genes that were differentially regulated between the two strains appeared to be transporters. These findings establish a platform for further studies of how this yeast survives and produces disease., IMPORTANCE Cryptococcus neoformans, an environmental, opportunistic yeast, is annually responsible for an estimated million cases of meningitis and over 600,000 deaths, mostly among HIV-infected patients in sub-Saharan Africa and Asia. Using RNA-seq, we analyzed the gene expression of two strains of C. neoformans obtained from the cerebrospinal fluid (CSF) of infected patients, thus creating a comprehensive snapshot of the yeasts’ genetic responses within the human body. By comparing the gene expression of each clinical strain under three conditions (in vivo CSF, ex vivo CSF, and laboratory culture), we identified genes and pathways that were uniquely regulated by exposure to CSF and likely crucial for the survival of C. neoformans in the central nervous system. Further analyses revealed genetic diversity between the strains, providing evidence for cryptococcal evolution and strain specificity. This ability to characterize transcription in vivo enables the elucidation of specific genetic responses that promote disease production and progression.
- Published
- 2014
21. Relationship between knee kinetics during jumping tasks and knee articular cartilage MRI T1rho and T2 relaxation times
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Richard B. Souza, Charles Fang, Anthony Luke, Samuel Wu, Sharmila Majumdar, and Xiaojuan Li
- Subjects
Adult ,Cartilage, Articular ,Knee Joint ,Biophysics ,Articular cartilage ,Osteoarthritis ,medicine.disease_cause ,Article ,Jumping ,Medicine ,Humans ,Orthopedics and Sports Medicine ,Range of Motion, Articular ,Orthodontics ,business.industry ,Cartilage ,Biomechanics ,Anatomy ,medicine.disease ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Healthy individuals ,T2 relaxation ,Female ,business ,Range of motion ,Locomotion - Abstract
Articular cartilage of young healthy individuals is dynamic and responsive to loading behaviors. The purpose of this study was to evaluate the relationship of cartilage T(1ρ) and T(2) relaxation times with loading kinetics during jumping tasks in healthy young individuals.Fourteen healthy subjects underwent: 1) motion analysis while performing a unilateral hopping task and bilateral drop jumping task; and 2) quantitative imaging using a 3 Tesla MRI for T(1ρ) and T(2) relaxation time analysis. Three dimensional net joint moments and angular impulse was calculated using standard inverse dynamics equations. Average T(1ρ) and T(2) relaxation times and medial-lateral ratios for each were calculated. Multiple regression was used to identify predictors of cartilage relaxation times.Average knee flexion moment during hopping was observed to best predict overall T(1ρ) (R(2)=.185) and T(2) (R(2)=.154) values. Peak knee adduction moment during a drop jump was the best predictor of the T(1ρ) medial-lateral ratio (R(2)=.220). The T(2) medial-lateral ratio was best predicted by average internal rotation moment during the drop jump (R(2)=.174).These data suggest that loads across the knee may affect the biochemistry of the cartilage. In young healthy individuals, higher flexion moments were associated with decreased T(1ρ) and T(2) values, suggesting a potentially beneficial effect. The medial-to-lateral ratio of T(1ρ) and T(2) times appears to be related to the frontal and transverse plane joint mechanics. These data offer promising findings of potentially modifiable parameters associated with cartilage composition.
- Published
- 2011
22. Evaluation of correction methods for coil-induced intensity inhomogeneities and their influence on trabecular bone structure parameters from MR images
- Author
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Jenny, Folkesson, Roland, Krug, Janet, Goldenstein, Ahi S, Issever, Charles, Fang, Thomas M, Link, and Sharmila, Majumdar
- Subjects
Aged, 80 and over ,Male ,Risk ,Phantoms, Imaging ,Equipment Design ,Magnetic Resonance Imaging ,Bone and Bones ,Fractures, Bone ,Cadaver ,Image Processing, Computer-Assisted ,Humans ,Female ,Femur ,Tomography, X-Ray Computed ,Aged - Abstract
Magnetic resonance (MR) imaging-based quantitative trabecular bone structure analysis has gained increasing interest in osteoporotic fracture risk assessment and treatment evaluation related to osteoporosis. In vivo MR images of anatomic regions such as the proximal femur and distal tibia are generally acquired with a surface coil in order to obtain sufficient sensitivity and resolution for quantification of the trabeculae. However, these coils introduce intensity inhomogeneities which affect the trabecular bone structure analysis. This work evaluates the applicability of a fully automatic coil correction by nonparametric nonuniform intensity normalization (N3) in the analysis of trabecular bone parameters. The ability to correct for coil-induced intensity inhomogeneity was evaluated ex vivo on proximal femur specimens scanned with both a surface coil and a volume coil, which allowed for a direct evaluation of the performance of the coil correction methods without any major confounding factors. In addition, trabecular bone parameter values were correlated with values from high-resolution peripheral computed tomography (HR-pQCT) scans, and the reproducibility of trabecular bone parameters was evaluated in an in vivo study of repeat hip MR scans. The trabecular bone parameters determined from MR surface coil scans processed with the N3 coil correction method showed significant correlation (p0.05) with corresponding values from homogeneous intensity data in the ex vivo study. This can be compared to the correlation without coil correction (p0.5), and coil correction using low-pass filtering (LPF) (p0.53). The in vivo interscan variability was reduced from 8.9% to 12.8% using LPF-based to 3.6%-8.4% (CV) using N3 coil correction; hence the results showed that N3 is advantageous to LPF-based coil correction. No significant differences in correlation to HR-pQCT data were found for the coil correction methods. The significant correlations with volume coil data and high reproducibility of the N3 processed data imply that N3 coil correction preserve image information while accurately correcting for coil-induced intensity inhomogeneities, which makes it suitable for quantitative analysis of trabecular bone structure from MR images acquired with surface coils.
- Published
- 2009
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