84 results on '"Samuel C Johnson"'
Search Results
2. Ultrafast infrared nano-imaging of far-from-equilibrium carrier and vibrational dynamics
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Jun Nishida, Samuel C. Johnson, Peter T. S. Chang, Dylan M. Wharton, Sven A. Dönges, Omar Khatib, and Markus B. Raschke
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Science - Abstract
Ultrafast infrared nano-imaging has enabled the study of nanoscale dynamics, but has been limited to probing short-lived carrier lifetimes. Here, the authors present pump-probe nano-spectroscopy with enhanced sensitivity to image both carrier and vibrational dynamics associated with long-lived excitations.
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- 2022
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3. The economic and reliability impacts of grid-scale storage in a high penetration renewable energy system
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Samuel C. Johnson, Dimitri J. Papageorgiou, Michael R. Harper, Joshua D. Rhodes, Kevin Hanson, and Michael E. Webber
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Grid reliability ,Rotational inertia ,Renewable energy ,Energy storage ,Unit commitment & dispatch ,Non-Synchronous generation ,Energy industries. Energy policy. Fuel trade ,HD9502-9502.5 - Abstract
As variable renewable energy generation in Texas increases over the next decade, flexibility and system inertia needs are likely to increase. Although natural gas peakers and combined cycle plants have met these demands in the past, grid-scale energy storage might be able to provide similar benefits. We compare the capacity for different energy storage technologies to provide grid inertia to maintain grid reliability and meet peak energy demand with a linearly-relaxed unit commitment and dispatch model of the Electric Reliability Council of Texas (ERCOT) grid that features fifteen transmission zones and sub-hourly intervals (i.e. 15 minutes). In this model, three energy storage technologies—Lithium-ion batteries, flywheels, and compressed air energy storage—are represented with different storage durations, ramp rates, and costs. Single-zone, 1 GW penetrations of each energy storage technology were modeled with a renewable energy penetration greater than 50% to identify the transmission zones where energy storage might have the greatest impact on the total cost of energy generation. Then, scenarios with 10 GW of energy storage either divided across the five transmission zones or concentrated in one zone at a time were modeled to analyze the impact of energy storage on inertia prices (reliability support) and total system costs (flexibility support) at scale. Energy storage built in transmission zones with high penetrations of variable renewable energy generation brought about the greatest reductions in system costs, so the 10 GW of storage were divided between five storage zones—transmission zones where building energy storage was most favorable—according to each zone’s economic impact. Our model showed that compressed air energy storage generated the lowest average inertia price and produced the lowest system costs. With deep penetrations of grid-scale energy storage, new peakers built in transmission zones where energy storage was added might become stranded assets in a high renewable energy future. In conclusion, compressed air energy storage systems most effectively supported the grid’s system inertia while simultaneously meeting the grid’s flexibility needs. Therefore, grid-scale energy storage offers a low-carbon solution to the variability of renewable energy generation.
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- 2021
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4. Acamprosate: Genes Associated With Response (ACAM)
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Samuel C. Johnson Foundation and David Mrazek, M.D.
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- 2013
5. Dynamic Maneuvers: A Useful Augmentation for Pelvic Sonography
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Samuel C. Johnson, Faysal A. Saksouk, and Patricia Balcacer
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Humans ,Radiology, Nuclear Medicine and imaging ,Sensitivity and Specificity ,Ultrasonography - Published
- 2022
6. Ultrafast infrared nano-thermometry: imaging thermal transport at semiconducting heterointerfaces
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Samuel C. Johnson, Shiqian Hu, Jun Nishida, Peter A. Chabal, Baowen Li, and Markus B. Raschke
- Abstract
We perform ultrafast pump-probe nano-spectroscopic imaging of WSe2-SiO2 interfaces. From transient phonon softening as a local probe of substrate temperature, we resolve heterogeneity in ps thermalization and quantify interfacial boundary conductance.
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- 2022
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7. Semi-empirical Quantum Optics for Mid-Infrared Molecular Nanophotonics
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Johan F. Triana, Mauricio Arias, Jun Nishida, Eric A. Muller, Roland Wilcken, Samuel C. Johnson, Aldo Delgado, Markus B. Raschke, and Felipe Herrera
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Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,FOS: Physical sciences ,General Physics and Astronomy ,Physical and Theoretical Chemistry ,Quantum Physics (quant-ph) ,Optics (physics.optics) ,Physics - Optics - Abstract
Nanoscale infrared (IR) resonators with sub-diffraction limited mode volumes and open geometries have emerged as new platforms for implementing cavity quantum electrodynamics (QED) at room temperature. The use of infrared (IR) nano-antennas and tip nanoprobes to study strong light-matter coupling of molecular vibrations with the vacuum field can be exploited for IR quantum control with nanometer and femtosecond resolution. In order to accelerate the development of molecule-based quantum nano-photonic devices in the mid-IR, we develop a generally applicable semi-empirical quantum optics approach to describe light-matter interaction in systems driven by mid-IR femtosecond laser pulses. The theory is shown to reproduce recent experiments on the acceleration of the vibrational relaxation rate in infrared nanostructures, and also provide physical insights for the implementation of coherent phase rotations of the near-field using broadband nanotips. We then apply the quantum framework to develop general tip-design rules for the experimental manipulation of vibrational strong coupling and Fano interference effects in open infrared resonators. We finally propose the possibility of transferring the natural anharmonicity of molecular vibrational levels to the resonator near-field in the weak coupling regime, to implement intensity-dependent phase shifts of the coupled system response with strong pulses. Our semi-empirical quantum theory is equivalent to first-principles techniques based on Maxwell's equations, but its lower computational cost suggests its use a rapid design tool for the development of strongly-coupled infrared nanophotonic hardware for applications ranging from quantum control of materials to quantum information processing., 18 pages, 7 figures
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- 2021
8. Evaluating rotational inertia as a component of grid reliability with high penetrations of variable renewable energy
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Joshua D. Rhodes, Michael E. Webber, Samuel C. Johnson, Thomas A. Deetjen, Dimitri J. Papageorgiou, and Dharik S. Mallapragada
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020209 energy ,media_common.quotation_subject ,02 engineering and technology ,Inertia ,Industrial and Manufacturing Engineering ,Automotive engineering ,Variable renewable energy ,Power system simulation ,020401 chemical engineering ,0202 electrical engineering, electronic engineering, information engineering ,0204 chemical engineering ,Electrical and Electronic Engineering ,Civil and Structural Engineering ,media_common ,business.industry ,Mechanical Engineering ,Building and Construction ,Nuclear power ,Moment of inertia ,Grid ,Pollution ,Renewable energy ,General Energy ,Electricity generation ,Environmental science ,business - Abstract
Growth of electricity generation from variable renewable resources like wind and solar has raised questions about future grid stability. This paper used several renewable energy penetration scenarios to determine when an electric grid might be more vulnerable to frequency contingencies, such as a generator outage. Unit commitment and dispatch modeling was used to quantify system inertia, an established proxy for grid stability. A case study of the Electric Reliability Council of Texas grid was used to illustrate the method. Results from the modeled scenarios showed that the Texas grid is resilient to major grid changes, even with relatively high penetrations ( ∼ 30% of annual energy generation compared to 18% in 2017) of renewable energy. However, retiring nuclear power plants and private-use networks in the model led to unstable inertia levels in our results. When the system inertia was constrained to meet a minimum threshold in our model, multiple coal and natural gas combined-cycle plants were dispatched at part-load or at their minimum operating level to maintain stable system inertia levels. This behavior is expected to expand with higher renewable energy penetrations and could occur on other electric grids that are reliant on synchronous generators for inertia support.
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- 2019
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9. Ultrafast infrared nano-imaging of far-from-equilibrium carrier and vibrational dynamics
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Jun, Nishida, Samuel C, Johnson, Peter T S, Chang, Dylan M, Wharton, Sven A, Dönges, Omar, Khatib, and Markus B, Raschke
- Abstract
Ultrafast infrared nano-imaging has demonstrated access to ultrafast carrier dynamics on the nanoscale in semiconductor, correlated-electron, or polaritonic materials. However, mostly limited to short-lived transient states, the contrast obtained has remained insufficient to probe important long-lived excitations, which arise from many-body interactions induced by strong perturbation among carriers, lattice phonons, or molecular vibrations. Here, we demonstrate ultrafast infrared nano-imaging based on excitation modulation and sideband detection to characterize electron and vibration dynamics with nano- to micro-second lifetimes. As an exemplary application to quantum materials, in phase-resolved ultrafast nano-imaging of the photoinduced insulator-to-metal transition in vanadium dioxide, a distinct transient nano-domain behavior is quantified. In another application to lead halide perovskites, transient vibrational nano-FTIR spatially resolves the excited-state polaron-cation coupling underlying the photovoltaic response. These examples show how heterodyne pump-probe nano-spectroscopy with low-repetition excitation extends ultrafast infrared nano-imaging to probe elementary processes in quantum and molecular materials in space and time.
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- 2021
10. Smart Scattering Scanning Near-Field Optical Microscopy
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Hans A. Bechtel, Rafael Piestun, Samuel C. Johnson, Markus B. Raschke, and Simon Labouesse
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Adaptive sampling ,Materials science ,Physics::Optics ,Near and far field ,02 engineering and technology ,Optical Physics ,01 natural sciences ,law.invention ,010309 optics ,Optics ,Optical microscope ,law ,0103 physical sciences ,Electrical and Electronic Engineering ,Image resolution ,Quantum ,Quantum Physics ,Scattering ,business.industry ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Compressed sensing ,Nanometre ,0210 nano-technology ,business ,Biotechnology - Abstract
Scattering scanning near-field optical microscopy (s-SNOM) provides spectroscopic imaging from molecular to quantum materials with few nanometer deep subdiffraction limited spatial resolution. However, in its conventional implementation s-SNOM is slow to effectively acquire a series of spatio-spectral images, especially with large fields of view. This problem is further exacerbated for weak resonance contrast or when using light sources with limited spectral irradiance. Indeed, the generally limited signal-to-noise ratio prevents sampling a weak signal at the Nyquist sampling rate. Here, we demonstrate how acquisition time and sampling rate can be significantly reduced by using compressed sampling, matrix completion, and adaptive random sampling, while maintaining or even enhancing the physical or chemical image content. We use fully sampled real data sets of molecular, biological, and quantum materials as ground-truth physical data and show how deep under-sampling with a corresponding reduction of acquisition time by 1 order of magnitude or more retains the core s-SNOM image information. We demonstrate that a sampling rate of up to 6× smaller than the Nyquist criterion can be applied, which would provide a 30-fold reduction in the data required under typical experimental conditions. Our smart s-SNOM approach is generally applicable and provides systematic full spatio-spectral s-SNOM imaging with a large field of view at high spectral resolution and reduced acquisition time.
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- 2020
11. The 'Speckle Sign' in the Diagnosis of Posterior Compartment Endometriosis
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Koenraad J. Mortele, Samuel C. Johnson, Adrian Jaramillo-Cardoso, Patricia Balcacer, and Sonia Gupta
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Adult ,medicine.medical_specialty ,Endometriosis ,030218 nuclear medicine & medical imaging ,Douglas' Pouch ,03 medical and health sciences ,Speckle pattern ,Young Adult ,0302 clinical medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Adenomyosis ,Pelvic compartment ,Compartment (pharmacokinetics) ,Aged ,Retrospective Studies ,Ultrasonography ,030219 obstetrics & reproductive medicine ,Radiological and Ultrasound Technology ,Pelvic free fluid ,business.industry ,Medical record ,Retrospective cohort study ,Middle Aged ,medicine.disease ,Female ,Radiology ,business - Abstract
Objective To determine usefulness of the "speckle sign" in the diagnosis of deep invasive endometriosis. Materials and methods This HIPAA-compliant, institutional review board-approved retrospective study with informed consent waived included 25 women (mean age 20-69 years) with histopathologically confirmed posterior cul-de-sac endometriosis between 2013 and 2018. Transvaginal ultrasound exams of these patients were reviewed by 2 expert radiologists searching for the "speckle sign," defined as irregular obliteration of the posterior cul-de-sac and bright (hyperechoic) internal echoes. The frequency of additional findings such as "kissing ovaries," endometriomas in the adnexa, bowel tethering in the posterior pelvic compartment, retroflexed uterus, adenomyosis, and pelvic free fluid were also analyzed. Data regarding clinical features, histopathologic findings and management were collected through a review of the medical record. Results Reader one identified posterior compartment endometriosis in 20/25 patients, and reader two in 22/25 patients, with 96% agreement. Adnexal endometriomas were found in 21/25 patients for both readers (k = 0.70) and were bilateral in 23% of patients. The ovaries were adherent to each other in the midline ("kissing ovaries") in 50% of patients; the bowel was tethered anteriorly in 20%; the presence of adenomyosis was seen in about 27%, and a retroflexed uterus was seen in 24% of patients. Conclusions The speckle sign could be helpful in making the diagnosis of posterior compartment endometriosis, and the sign is often found in conjunction with other imaging features of endometriosis.
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- 2020
12. Amniotic sheets
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null Samuel C. Johnson, MD and null Walter Villalobos
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- 2020
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13. Stretching and Heating Single DNA Molecules with Optically Trapped Gold–Silica Janus Particles
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Samuel C. Johnson, Jan Lipfert, Sabrina Simoncelli, Franziska Kriegel, and Jochen Feldmann
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0301 basic medicine ,Quantitative Biology::Biomolecules ,Range (particle radiation) ,Materials science ,Nanotechnology ,Janus particles ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Optical tweezers ,chemistry ,Chemical physics ,Thermal ,Molecule ,Particle ,Electrical and Electronic Engineering ,0210 nano-technology ,Nanoscopic scale ,DNA ,Biotechnology - Abstract
Self-propelled micro- and nanoscale motors are capable of autonomous motion typically by inducing local concentration gradients or thermal gradients in their surrounding medium. This is a result of the heterogeneous surface of the self-propelled structures that consist of materials with different chemical or physical properties. Here we present a self-thermophoretically driven Au–silica Janus particle that can simultaneously stretch and partially melt a single double-stranded DNA molecule. We show that the effective force acting on the DNA molecule is in the ∼pN range, well suited to probe the entropic stretching regime of DNA, and we demonstrate that the local temperature enhancement around the gold side of the particle produces partial DNA dehybridization.
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- 2017
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14. Endometriosis and Imaging
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Elizabeth E. Puscheck, Luis R. Hoyos, and Samuel C. Johnson
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medicine.medical_specialty ,Endometriosis ,Computed tomography ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,X ray computed ,Medical imaging ,Humans ,Medicine ,Ultrasonography ,030219 obstetrics & reproductive medicine ,medicine.diagnostic_test ,business.industry ,Obstetrics and Gynecology ,Magnetic resonance imaging ,medicine.disease ,Magnetic Resonance Imaging ,Ultrasound techniques ,Transvaginal ultrasound ,Female ,Radiology ,Tomography ,Tomography, X-Ray Computed ,business - Abstract
Endometriosis is a condition with variable location, size, and lesion composition which poses a diagnostic imaging challenge for the practicing gynecologist. Transvaginal ultrasound and magnetic resonance imaging are the most frequent imaging techniques used for its evaluation, but transvaginal ultrasound should be the first-line approach, as it is often sufficient, followed by modified ultrasound techniques. Magnetic resonance imaging should be considered when a diagnosis has not been achieved by sonographic means or when the renal system needs to be concurrently evaluated. Computed tomography has no role in the routine evaluation of endometriosis except in very few particular scenarios.
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- 2017
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15. Sonovaginography: A Useful Technique in the Assessment of the Lower Genital Tract
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Samuel C. Johnson, N. Tugce Yegul, and Patricia Balcacer
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medicine.medical_specialty ,030219 obstetrics & reproductive medicine ,Radiological and Ultrasound Technology ,business.industry ,Transperineal approach ,Ultrasound ,Anatomy ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Vaginal canal ,030220 oncology & carcinogenesis ,medicine ,Vagina ,Radiology, Nuclear Medicine and imaging ,Physical exam ,Radiology ,Lower genital tract ,Abnormality ,business ,Cervix - Abstract
Conventional sonographic evaluation of the cervix and vagina is compromised by inattention, poor subject contrast, and obscuring artifacts. We describe a technique involving distention of the vaginal canal and fornices with ultrasound gel, providing an acoustic window for improved definition of the cervix and vagina. This exam is usually performed in concert with transvaginal sonography, but a transabdominal or transperineal approach may be more useful in selected scenarios. A wide variety of formerly sonographically inconspicuous conditions are demonstrable with this technique, many of which were undetected or inadequately characterized on the physical exam. Cervical polyps were the most commonly seen abnormality.
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- 2017
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16. How different power plant types contribute to electric grid reliability, resilience, and vulnerability: a comparative analytical framework
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Thomas A. Deetjen, Samuel C. Johnson, W. Neal Mann, Katrina Ramirez-Meyers, Michael E. Webber, and Joshua D. Rhodes
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Electricity generation ,Power station ,Vulnerability ,Environmental science ,General Medicine ,Grid ,Resilience (network) ,Reliability (statistics) ,Reliability engineering - Abstract
This work explores the dependability tradeoffs provided by the most common types of central power plants in the United States. Historically, the electricity sector has lacked consensus on how reliability, resilience, and vulnerability differ and how those metrics change depending on the power plant fleet composition. We propose distinct definitions for these metrics and an analytical framework to evaluate power plant fleet dependability. Using data analysis and literature review, we identify fifteen dependability attributes across which we rank eleven power plant types relative to natural gas combined-cycle (NGCC) plants. We use NGCC as the benchmark because it is common to many locations and is of relatively recent vintage. The framework shows that each power plant type has unique dependability benefits and drawbacks. We provide examples of how researchers may use the framework to evaluate grid dependability qualitatively under different scenarios. We find that assuming all attributes that contribute to grid dependability are equally important and additive, electric grid dependability is best supported when power plant fleets include a mixture of power generation technologies. Then, we discuss scenario characteristics that could alter the prioritization and relationships of attributes. We also find that if current capacity installation trends continue to favor low- and zero-carbon power plants, US power grids may benefit from increased resilience and reduced vulnerability at the cost of decreased reliability. We conclude by recommending methods for adapting the framework and quantifying relationships between attributes in individual scenarios.
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- 2021
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17. Reply to The ‘Speckle Sign’ in the Diagnosis of Posterior Compartment Endometriosis
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Samuel C. Johnson and Patricia Balcacer
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Pathology ,medicine.medical_specialty ,Speckle pattern ,Radiological and Ultrasound Technology ,business.industry ,medicine ,Endometriosis ,Radiology, Nuclear Medicine and imaging ,Compartment (pharmacokinetics) ,business ,medicine.disease - Published
- 2021
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18. Synchrotron infrared nano-spectroscopy and -imaging
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Hans A. Bechtel, Eric A. Muller, Omar Khatib, Markus B. Raschke, and Samuel C. Johnson
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Materials science ,Infrared ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,law.invention ,Scanning probe microscopy ,Optics ,law ,Materials Chemistry ,Imaging science ,Fourier transform infrared spectroscopy ,Spectroscopy ,business.industry ,Surface plasmon ,Analytical technique ,Metals and Alloys ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Synchrotron ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Astrophysics::Earth and Planetary Astrophysics ,0210 nano-technology ,business - Abstract
Infrared (IR) spectroscopy has evolved into a powerful analytical technique to probe molecular and lattice vibrations, low-energy electronic excitations and correlations, and related collective surface plasmon, phonon, or other polaritonic resonances. In combination with scanning probe microscopy, near-field infrared nano-spectroscopy and -imaging techniques have recently emerged as a frontier in imaging science, enabling the study of complex heterogeneous materials with simultaneous nanoscale spatial resolution and chemical and quantum state spectroscopic specificity. Here, we describe synchrotron infrared nano-spectroscopy (SINS), which takes advantage of the low-noise, broadband, high spectral irradiance, and coherence of synchrotron infrared radiation for near-field infrared measurements across the mid- to far-infrared with nanometer spatial resolution. This powerful combination provides a qualitatively new form of broadband spatio-spectral analysis of nanoscale, mesoscale, and surface phenomena that were previously difficult to study with IR techniques, or even any form of micro-spectroscopy in general. We review the development of SINS, describe its technical implementations, and highlight selected examples representative of the rapidly growing range of applications in physics, chemistry, biology, materials science, geology, and atmospheric and space sciences.
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- 2020
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19. Selecting Favorable Energy Storage Technologies for Nuclear Power
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Samuel C. Johnson, Justin Coleman, Joshua D. Rhodes, Eric J. Dufek, F. Todd Davidson, Shannon Bragg-Sitton, and Michael E. Webber
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business.industry ,Water storage ,Nuclear power ,Thermal energy storage ,Potential energy ,Energy storage ,law.invention ,law ,Nuclear power plant ,Environmental science ,Environmental impact assessment ,Heuristics ,business ,Process engineering - Abstract
Energy storage technologies can enable nuclear power plants to follow electricity demand throughout the day and minimize cycling costs. Several dynamic performance requirements and heuristics (such as cost and environmental impact) are presented in this chapter to compare energy storage technologies that could be integrated with nuclear power. These characteristics are compared to suggest potential energy storage integration options for Plant Vogtle units 3 and 4, two pressurized-water nuclear reactors being built in the United States. This chapter suggests that thermal energy storage technologies such as hot and cold water storage might be the most favorable for integration with a nuclear power plant due to their low cost and limited environmental impact.
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- 2019
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20. Contributors
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Hitesh Bindra, Shannon M. Bragg-Sitton, Haisheng Chen, Justin L. Coleman, Lin Cong, Yulong Ding, Eric J. Dufek, Abhinav Gairola, Kathryn D. Huff, Samuel C. Johnson, Yongliang Li, Xiaodong Peng, Shripad T. Revankar, Joshua D. Rhodes, null Rizwan-uddin, Piyush Sabharwal, Sudhansu Sahoo, Xiaohui She, F. Todd Davidson, Lige Tong, Li Wang, Michael E. Webber, Graham Wilson, Qinghua Yu, Tongtong Zhang, Xiaosong Zhang, and Xinjing Zhang
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- 2019
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21. IN-SITU CHEMICAL ANALYSIS OF HYDROCARBONS AT A NANOPORE SCALE, CRETACEOUS NIOBRARA FORMATION, DENVER BASIN, COLORADO
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Omar Khatib, Samuel C. Johnson, Rebekah E. Simon, Markus B. Raschke, and David A. Budd
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In situ ,Nanopore ,Scale (ratio) ,Geochemistry ,Structural basin ,Geology ,Cretaceous ,Niobrara Formation - Published
- 2019
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22. Understanding the impact of non-synchronous wind and solar generation on grid stability and identifying mitigation pathways
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Samuel C. Johnson, Michael E. Webber, and Joshua D. Rhodes
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business.industry ,020209 energy ,Mechanical Engineering ,media_common.quotation_subject ,02 engineering and technology ,Building and Construction ,Management, Monitoring, Policy and Law ,Moment of inertia ,Inertia ,Grid ,Energy storage ,Automotive engineering ,Renewable energy ,General Energy ,Power system simulation ,Electricity generation ,020401 chemical engineering ,Limit (music) ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,0204 chemical engineering ,business ,media_common - Abstract
High penetrations of non-synchronous renewable energy generation can decrease overall grid stability because these units do not provide rotational inertia in the same way as traditional synchronously-connected generators. Many recent studies have investigated 100% renewable energy generation scenarios, but few have explored the trade-offs associated with an electricity grid dominated by non-synchronous generation (i.e. wind and solar). Fast frequency response from grid-forming inverters—along with other technology changes—could help mitigate low system inertia levels, but the impact of this response is unknown. An inertia-constrained unit commitment and dispatch model was used to study the stability of future grid scenarios with high penetrations of non-synchronous renewable energy generation under a variety of technology scenarios. The Texas grid (the Electric Reliability Council of Texas – ERCOT) was used as a test case and instances when the system inertia fell below 100 GW · s (the grid’s current minimum level) were recorded. When the modeled critical inertia limit was reduced to 80 GW · s to represent changes in grid operation, no critical inertia hours occurred for renewable energy penetrations up to 93% of annual energy. The critical inertia limit could drop to 60 GW · s if the largest generators in ERCOT (two co-located nuclear plants) were retired, but emissions increased by ~ 25% in these scenarios. If the critical inertia limit was kept the same (100 GW · s), adding 525 MW of fast frequency response from wind, solar, and energy storage could reduce the number of critical inertia hours by up to 95%. These results show that changes to grid operating practices and generator retirements reduced critical inertia hours more than fast frequency response from inverter-connected resources. Each of these mitigation pathways has associated trade-offs, so the transition to a grid dominated by non-synchronous energy generation should be handled with care, but high renewable energy penetrations (i.e. >80%) might be feasible in Texas.
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- 2020
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23. Optical Probe Thermometry Using Optically Trapped Erbium Oxide Nanoparticles
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Susil Baral, Samuel C. Johnson, Hugh H. Richardson, and Arwa A. Alaulamie
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Materials science ,Spinodal decomposition ,Nucleation ,Nanowire ,Nanoparticle ,chemistry.chemical_element ,Laser ,Molecular physics ,law.invention ,Erbium ,chemistry ,law ,Melting point ,Water vapor - Abstract
A new thermal imaging technique is characterized that uses an optically trapped erbium oxide nanoparticle cluster of approximately 150 nm. This technique can measure absolute temperature and has an imaging spatial resolution of the trapped particle. Scanning optical probe thermometry has been used to thermally image a cluster of gold nanowires that were excited with the trapping laser. Following a deconvolution of the measured thermal profile, a point spread function of the imaging technique has been determined to be a Gaussian with a FWHM of 165 nm. This width is a function of the clustering of Er2O3 nanoparticles used to image the nanowire. Optical probe thermometry has further been used to measure the temperature of nucleation events where a dichotomy of temperature for nucleated water occurs from degassed water and native water. Degassed water has been measured to nucleate at 555K confirming water adjacent to the gold nanoparticle superheats to the spinodal decomposition temperature before nucleating into a water vapor bubble. Following this event, the temperature inside the vapor bubble rises to the melting point of the gold nanoparticle, 1300 K which is followed by temperature stabilization. The rapid and significant temperature increase is attributed to the loss of a thermal dissipation pathway, to the surrounding water, previously available to the gold nanoparticle due to the insulator nature of the growing vapor envelope around the gold nanoparticle.
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- 2015
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24. Delayed debridement of severe open fractures is associated with a higher rate of deep infection
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Peter Hull, Samuel C Johnson, David Stephen, Hans J. Kreder, and Richard Jenkinson
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Adult ,Aged, 80 and over ,Male ,medicine.medical_specialty ,Open fracture ,Time Factors ,Debridement ,Adolescent ,business.industry ,medicine.medical_treatment ,Surgical debridement ,Delayed treatment ,Middle Aged ,Surgery ,Fractures, Open ,Risk Factors ,Wound Infection ,Humans ,Medicine ,Female ,Orthopedics and Sports Medicine ,business ,Aged - Abstract
This study explores the relationship between delay to surgical debridement and deep infection in a series of 364 consecutive patients with 459 open fractures treated at an academic level one trauma hospital in North America. The mean delay to debridement for all fractures was 10.6 hours (0.6 to 111.5). There were 46 deep infections (10%). There were no infections among the 55 Gustilo-Anderson grade I open fractures. Among the grade II and III injuries, a statistically significant increase in the rate of deep infection was found for each hour of delay (OR = 1.033: 95% CI 1.01 to 1.057). This relationship shows a linear increase of 3% per hour of delay. No distinct time cut-off points were identified. Deep infection was also associated with tibial fractures (OR = 2.44: 95% CI 1.26 to 4.73), a higher Gustilo-Anderson grade (OR = 1.99: 95% CI 1.004 to 3.954), and contamination of the fracture (OR = 3.12: 95% CI 1.36 to 7.36). These individual effects are additive, which suggests that delayed debridement will have a clinically significant detrimental effect on more severe open fractures. Delayed treatment appeared safe for grade 1 open fractures. However, when the negative prognostic factors of tibial site, high grade of fracture and/or contamination are present we recommend more urgent operative debridement. Cite this article: Bone Joint J 2014;96-B:379–84.
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- 2014
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25. Sonovaginography: A Useful Technique in the Assessment of the Lower Genital Tract
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Samuel C, Johnson, N Tugce, Yegul, and Patricia, Balcacer
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Adult ,Uterine Cervical Diseases ,Vagina ,Vaginal Diseases ,Humans ,Female ,Cervix Uteri ,Sensitivity and Specificity ,Ultrasonography - Abstract
Conventional sonographic evaluation of the cervix and vagina is compromised by inattention, poor subject contrast, and obscuring artifacts. We describe a technique involving distention of the vaginal canal and fornices with ultrasound gel, providing an acoustic window for improved definition of the cervix and vagina. This exam is usually performed in concert with transvaginal sonography, but a transabdominal or transperineal approach may be more useful in selected scenarios. A wide variety of formerly sonographically inconspicuous conditions are demonstrable with this technique, many of which were undetected or inadequately characterized on the physical exam. Cervical polyps were the most commonly seen abnormality.
- Published
- 2016
26. Nanothermometry using optically trapped erbium oxide nanoparticle
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Hugh H. Richardson, Samuel C. Johnson, Arwa A. Alaulamie, and Susil Baral
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Materials science ,Nanostructure ,business.industry ,Spinodal decomposition ,Nucleation ,Analytical chemistry ,Physics::Optics ,Nanoparticle ,02 engineering and technology ,General Chemistry ,Thermal transfer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Superheating ,Melting point ,Optoelectronics ,General Materials Science ,Nanodot ,0210 nano-technology ,business - Abstract
A new optical probe technique using a laser-trapped erbium oxide nanoparticle (size ~150 nm) is introduced that can measure absolute temperature with a spatial resolution on the size of the trapped nanoparticle. This technique (scanning optical probe thermometry) is used to collect a thermal image of a gold nanodot prepared with hole-mask colloidal lithography. A convolution analysis of the thermal profile shows that the point spread function of our measurement is a Gaussian with a FWHM of 165 nm. We attribute the width of this function to clustering of Er2O3 nanoparticles in solution. The scanning optical probe thermometer is used to measure the temperature where vapor nucleation occurs in degassed water (555 K), confirming that a nanoscale object heated in water will superheat the surrounding water to the spinodal decomposition temperature. Subsequently, the temperature inside the vapor bubble rises to the melting point of the gold nanostructure (~1300) where a temperature plateau is observed. The rise in temperature is attributed to inhibition of thermal transfer to the surrounding liquid by the thermal insulating vapor cocoon.
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- 2016
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27. The role of sonographic endometrial patterns and endometrial thickness in the differential diagnosis of ectopic pregnancy
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Michael P. Diamond, Emmanuel Bujold, Bernard Gonik, Ihab Hammoud, Samuel C. Johnson, and Ahmad O. Hammoud
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Adult ,medicine.medical_specialty ,Uterus ,Endometrium ,Sensitivity and Specificity ,Cohort Studies ,Diagnosis, Differential ,Pregnancy ,medicine ,Humans ,Chorionic Gonadotropin, beta Subunit, Human ,Retrospective Studies ,Ultrasonography ,Gynecology ,Receiver operating characteristic ,Ectopic pregnancy ,business.industry ,Obstetrics and Gynecology ,Retrospective cohort study ,medicine.disease ,Pregnancy, Ectopic ,medicine.anatomical_structure ,ROC Curve ,In utero ,Female ,Differential diagnosis ,business - Abstract
Objective The purpose of this study was to examine the usefulness of the endometrial trilaminar pattern and thickness in the diagnosis of ectopic pregnancy. Study design We reviewed patient records for clinical and ultrasonographic data for patients with the suspicion of ectopic pregnancy. The trilaminar pattern and endometrial thickness were tested as predictors for the diagnosis of ectopic pregnancy. Results The trilaminar pattern had a specificity of 94% and sensitivity of 38% (n=403 women). The mean endometrial thickness was thinner in patients with ectopic, compared with normal pregnancy (9.5 ± 5.7 mm vs 12.4 ± 5.9 mm; P =.035). Patients with normal pregnancy or first-trimester losses had comparable thicknesses (12.4 ± 5.9 mm vs 12.5 ± 8.0 mm). The receiver operator curve showed that there was no thickness value useful for the diagnosis of ectopic pregnancy. Conclusion The trilaminar pattern is specific for the diagnosis of ectopic pregnancy, but it is associated with low sensitivity. The endometrial thickness tends to be thinner in patients with an ectopic pregnancy.
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- 2005
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28. Recognition of the Ovaries and Ovarian Origin of Pelvic Masses with CT
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Samuel C. Johnson and Faysal A. Saksouk
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Adult ,medicine.medical_specialty ,endocrine system diseases ,Iliac Lymph Node ,business.industry ,Suspensory ligament ,Ovary ,Uterus ,Anatomy ,Middle Aged ,Pelvis ,medicine.anatomical_structure ,Ureter ,Abdominal Neoplasms ,Ligament ,Humans ,Medicine ,Female ,Radiology, Nuclear Medicine and imaging ,Radiology ,Tomography, X-Ray Computed ,business ,Ovarian vein - Abstract
Knowledge of the morphologic features and ligamentous attachments of the ovaries, the relationship of the ovary to the ureter, and the course of the ovarian vein and artery is necessary for confident recognition of the ovaries and differentiation between ovarian and nonovarian masses with computed tomography (CT). The suspensory ligament attaches the ovary to the pelvic sidewall and transmits the ovarian vein and artery. This ligament may be seen at CT as a linear or fan-shaped soft-tissue band leading to the ovary. The utero-ovarian ligament is occasionally visualized with CT as a soft-tissue band between the uterus and ovary. The ovaries are usually located anterior or anteromedial to the pelvic ureters, whereas iliac lymph nodes are lateral or posterolateral to the ureters. Therefore, an ovarian mass displaces the ureter posteriorly or posterolaterally, whereas a large lymph node mass displaces the ureter medially or anteromedially. An ovarian mass may be draped by ovarian parenchyma, thus revealing the origin of the mass. Tracking the ovarian vein from near the level of the renal vessels caudally to the pelvis leads to the suspensory ligament region and is often helpful in identifying the ovary and differentiating ovarian and nonovarian masses.
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- 2004
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29. Postarthroplasty Hip Dysfunction: Imaging and Intervention
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Sam Nasser, Samuel C. Johnson, David R. Lucas, and Peter R. Miller
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musculoskeletal diseases ,medicine.medical_specialty ,business.industry ,Implant failure ,Perioperative ,equipment and supplies ,Surgery ,Review article ,surgical procedures, operative ,Intervention (counseling) ,medicine ,Radiology, Nuclear Medicine and imaging ,Implant ,Aseptic processing ,business - Abstract
This review article divides postarthroplasty hip dysfunction into four subsets of complications: aseptic implant loosening, septic implant loosening, structural implant failure, and tumor. These subsets usually develop as late postoperative complications. The serious perioperative complications of w
- Published
- 2003
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30. Merkel cell carcinoma in a patient with noninvasive vulvar Paget's disease
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Gunter Deppe, Samuel C. Johnson, Ira Winer, and Fulvio Lonardo
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medicine.medical_specialty ,Pathology ,Skin Neoplasms ,Vulvar Neoplasms ,integumentary system ,business.industry ,Merkel cell carcinoma ,Obstetrics and Gynecology ,Neoplasms, Second Primary ,Disease ,Groin ,medicine.disease ,Dermatology ,Metastasis ,Carcinoma, Merkel Cell ,Paget Disease, Extramammary ,Vulvar Paget's Disease ,Unknown primary ,Humans ,Neoplasms, Unknown Primary ,Medicine ,Female ,business ,Aged - Abstract
We present the first case of inguinal Merkel cell carcinoma of unknown primary origin in a patient with vulvar Paget's disease. Correlation with immune suppression of both entities warrants further investigation. Additionally, this case highlights the value of ultrasound scanning in the detection of inguinal metastasis.
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- 2012
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31. Ultrasound imaging of fibroids and infertility
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Elizabeth E. Puscheck, Samuel C. Johnson, and Terri L. Woodard
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Infertility ,medicine.medical_specialty ,business.industry ,Ultrasound imaging ,medicine ,Radiology ,medicine.disease ,business - Published
- 2014
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32. Müllerian anomaly and ultrasonographic diagnosis
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Samuel C. Johnson, Awoniyi O. Awonuga, Elizabeth E. Puscheck, and M. Singh
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Gynecology ,Bicornuate uterus ,medicine.medical_specialty ,medicine.diagnostic_test ,Arcuate uterus ,business.industry ,Unicornuate uterus ,medicine.disease ,Müllerian agenesis ,Obstetrics and gynaecology ,medicine ,3D ultrasound ,Hysterosalpingography ,Differential diagnosis ,business - Published
- 2014
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33. Delayed wound closure increases deep-infection rate associated with lower-grade open fractures: a propensity-matched cohort study
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Samuel C Johnson, Hans J. Kreder, David Stephen, Richard Jenkinson, and Alexander Kiss
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Adult ,Male ,medicine.medical_specialty ,Time Factors ,medicine.medical_treatment ,Cohort Studies ,Fractures, Open ,McNemar's test ,Injury Severity Score ,medicine ,Humans ,Surgical Wound Infection ,Orthopedics and Sports Medicine ,Orthopedic Procedures ,Propensity Score ,Retrospective Studies ,Wound Healing ,Debridement ,business.industry ,Trauma center ,Retrospective cohort study ,General Medicine ,Confidence interval ,Surgery ,Propensity score matching ,Female ,business ,Algorithms ,Cohort study - Abstract
Background: Primary closure of skin wounds after debridement of open fractures is controversial. The purpose of the present study was to determine whether primary skin closure for grade-IIIA or lower-grade open extremity fractures is associated with a lower deep-infection rate. Methods: We identified 349 Gustilo-Anderson grade-I, II, or IIIA fractures treated at our level-I academic trauma center from 2003 to 2007. Eighty-seven injuries were treated with delayed primary closure, and 262 were treated with immediate closure after surgical debridement. After application of a propensity score-matching algorithm to balance prognostic factors, 146 open fractures (seventy-three matched pairs) were analyzed. Results: After application of a propensity score-matching algorithm with adjustment for age, sex, time to debridement, American Society of Anesthesiologists (ASA) class, fracture grade, evidence of gross contamination, and a tibial fracture rather than a fracture at another anatomic site, the two treatment groups were compared with respect to the prevalence of infection. Deep infection developed at the sites of three of the seventy-three fractures treated with immediate closure (infection rate, 4.1%; 95% confidence interval [CI], 0.86 to 11.5) compared with thirteen in the matched group of seventy-three fractures treated with delayed primary closure (infection rate, 17.8%; 95% CI, 9.8 to 28.5) (McNemar test, p = 0.0001). Conclusions: Immediate closure of carefully selected wounds by experienced surgeons treating grade-I, II, and IIIA open fractures is safe and is associated with a lower infection rate compared with delayed primary closure. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
- Published
- 2014
34. Transvaginal ultrasound-guided aspiration of pelvic abscesses
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Bernard Gonik, Michael P. Diamond, S.G. McNeeley, P.J. Corsi, S.L. Hendrix, and Samuel C. Johnson
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Adult ,Suction (medicine) ,medicine.medical_specialty ,Tuboovarian abscess ,Less invasive ,Dermatology ,Suction ,lcsh:Gynecology and obstetrics ,Pelvic abscess ,lcsh:Infectious and parasitic diseases ,Endosonography ,Pregnancy ,Pelvic inflammatory disease ,Humans ,Medicine ,lcsh:RC109-216 ,Ovarian Diseases ,Abscess ,lcsh:RG1-991 ,Aged ,Retrospective Studies ,business.industry ,Obstetrics and Gynecology ,Retrospective cohort study ,Fallopian Tube Diseases ,Middle Aged ,bacterial infections and mycoses ,medicine.disease ,humanities ,Surgery ,body regions ,Treatment Outcome ,Infectious Diseases ,Transvaginal ultrasound ,Female ,business ,Follow-Up Studies ,Pelvic Inflammatory Disease ,Research Article - Abstract
Objective: To assess the utility of a less invasive approach to the care of women with a pelvic abscess, we retrospectively reviewed the outcome of women with pelvic abscesses managed by transvaginal ultrasound-guided aspiration.Methods: A retrospective analysis of 27 pelvic abscesses in 22 consecutive women undergoing transvaginal drainage, including 13 tuboovarian abscesses (TOAs) and 14 postoperative abscesses (POAs). All patients received broad-spectrum intravenous antibiotics from the time infection was diagnosed to resolution of signs and symptoms. Chart review and examination of ultrasound files were utilized to extract demographic clinical, laboratory, and outcome data.Results: The mean age for the study group was 30 years old. Mean duration from diagnosis to drainage was 5.6 days (TOA) and 2.0 days (POA), P < 0.01. The mean diameter of the abscesses was 86 mm. The volume of purulent material drained ranged from 70–750 mL. Perceived adequacy of drainage was correlated with lack of abscess septation. Cultures for aerobic and anaerobic pathogens were positive in 51% of cases (79% POA versus 23% TOA, P < 0.05) with 1.9 organisms/ positive culture. Transvaginal drainage was successful in 25 of 27 abscesses. No complications were reported.Conclusion: In skilled hands, transvaginal guided aspiration of pelvic abscess is a highly successful technique with minimal risk to the patient. Follow-up studies are needed to assess the long-term sequelae, such as frequency of infertility, ectopic pregnancy, and chronic pelvic pain. Infect. Dis. Obstet. Gynecol. 7:216–221, 1999.
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- 1999
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35. Sonography of postpartum ovarian vein thrombophlebitis
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Maribel Esclapes and Samuel C. Johnson
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medicine.medical_specialty ,business.industry ,Vascular disease ,Medical record ,medicine.disease ,Thrombophlebitis ,Inferior vena cava ,Surgery ,Phlegmon ,medicine.vein ,cardiovascular system ,Medicine ,Radiology, Nuclear Medicine and imaging ,Radiology ,Thrombus ,business ,Hydronephrosis ,Ovarian vein - Abstract
Purpose We report the gray-scale, color, and power Doppler findings in 3 cases of postpartum ovarian vein thrombophlebitis (PPOVT), an uncommon but potentially lethal disorder. Methods A retrospective review of medical records revealed 3 patients with PPOVT who had pelvic sonography performed during the disease course. Results The sonographic findings of PPOVT included a tubular, hypoechoic mass identified anterior to the psoas muscle in all cases. Perivenous phlegmon formation resulted in hydronephrosis and obstructive periureteritis in 1 case. Inferior vena cava involvement was detected in 2 cases. Decreases in the sizes of the thrombus and the phlegmon were seen on post-treatment studies. Conclusions The long course of the thrombosed ovarian vein and the presence of inferior vena cava thrombus are sonographic signs helpful in distinguishing PPOVT from other inflammatory conditions. Sonography cannot be proposed as a primary tool in the diagnosis of PPOVT because it successfully diagnosed only 1 of our 3 cases. However, sonography may be useful in monitoring the response to anticoagulant therapy. © 1998 John Wiley & Sons, Inc. J Clin Ultrasound26:143–149, 1998.
- Published
- 1998
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36. Targeted Nanoparticle Thermometry: A Method to Measure Local Temperature at the Nanoscale Point Where Water Vapor Nucleation Occurs
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Samuel C. Johnson, Susil Baral, Hugh H. Richardson, and Arwa A. Alaulamie
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Chemistry ,Bubble ,Nucleation ,Physics::Optics ,Nanoparticle ,Thermodynamics ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Biomaterials ,Superheating ,Boiling point ,Chemical physics ,General Materials Science ,Nanorod ,Liquid bubble ,0210 nano-technology ,Physics::Atmospheric and Oceanic Physics ,Water vapor ,Biotechnology - Abstract
An optical nanothermometer technique based on laser trapping, moving and targeted attaching an erbium oxide nanoparticle cluster is developed to measure the local temperature. The authors apply this new nanoscale temperature measuring technique (limited by the size of the nanoparticles) to measure the temperature of vapor nucleation in water. Vapor nucleation is observed after superheating water above the boiling point for degassed and nondegassed water. The average nucleation temperature for water without gas is 560 K but this temperature is lowered by 100 K when gas is introduced into the water. The authors are able to measure the temperature inside the bubble during bubble formation and find that the temperature inside the bubble spikes to over 1000 K because the heat source (optically-heated nanorods) is no longer connected to liquid water and heat dissipation is greatly reduced.
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- 2016
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37. Complete septate uterus, obstructed hemivagina, and ipsilateral renal anomaly: pregnancy course complicated by a rare urogenital anomaly
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Jay M. Berman, Michael P. Diamond, Samuel C. Johnson, Samantha E. Montgomery, and Valerie I. Shavell
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medicine.medical_specialty ,UROGENITAL ANOMALY ,Kidney ,Obstructed hemivagina ,Young Adult ,Pregnancy ,medicine ,Humans ,Complicated pregnancy ,reproductive and urinary physiology ,Obstetrics ,business.industry ,Cesarean Section ,Uterus ,Obstetrics and Gynecology ,General Medicine ,medicine.disease ,Pregnancy Complications ,Renal anomaly ,Urogenital Abnormalities ,Vagina ,Female ,Female Reproductive Tract ,Kidney abnormalities ,business ,Septate uterus - Abstract
Abnormalities of the female reproductive tract are associated with a multitude of intrapartum complications. In the case that follows, we report the complicated pregnancy course of a woman diagnosed postpartum with the uncommon syndrome of obstructed hemivagina and ipsilateral renal anomaly (OHVIRA) associated with a complete septate uterus.A 19-year-old nulliparous woman with a history of a right nephrectomy secondary to multicystic dysplastic kidney disease presented with premature rupture of membranes at 30 weeks' gestation. After failed induction of labor at 34 weeks' gestation, a uterine anomaly was discovered at the time of cesarean section. Magnetic resonance imaging performed postpartum revealed a complete septate uterus, longitudinal vaginal septum, and obstructed right hemivagina.The OHVIRA syndrome is classically associated with uterus didelphys, not complete septate uterus as in this woman. This case illustrates the potential for intrapartum complications in women with abnormalities of the urogenital tract.
- Published
- 2008
38. First-trimester Doppler investigation of the uterine circulation
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Elizabeth E. Puscheck, Laura Detti, Michael P. Diamond, and Samuel C. Johnson
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medicine.medical_specialty ,symbols.namesake ,Pre-Eclampsia ,Predictive Value of Tests ,Pregnancy ,Placenta ,medicine ,Humans ,Fetus ,Fetal Growth Retardation ,Obstetrics ,business.industry ,Uterus ,Obstetrics and Gynecology ,Ultrasonography, Doppler ,Laser Doppler velocimetry ,medicine.disease ,Placentation ,Pregnancy Complications ,Uterine circulation ,First trimester ,Pregnancy Trimester, First ,medicine.anatomical_structure ,Regional Blood Flow ,symbols ,Gestation ,Female ,business ,Doppler effect ,Blood Flow Velocity - Abstract
There is now strong evidence that fetal events can significantly impact postnatal health and disease development. Doppler velocimetry can identify some early pathologic changes in pregnancy. Many investigators have tried to delineate the normal and pathologic models of the uterine circulation in the first trimester, but much has yet to be defined. A discrete amount of confusion derives from the incomplete knowledge of the initial placental development, and particularly the development of the intervillous circulation. This article comprehensively reviews the literature on first-trimester Doppler in both normal and complicated pregnancies, and briefly discusses potential future areas of application.
- Published
- 2005
39. Sonographic diagnosis of multiple unilateral ovarian teratomas
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Samuel C. Johnson and George L. Jordan
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Ovarian Neoplasms ,Pathology ,medicine.medical_specialty ,Radiological and Ultrasound Technology ,business.industry ,Teratoma ,Ovary ,Semiology ,Middle Aged ,medicine.disease ,medicine.anatomical_structure ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Female ,Ovarian Teratoma ,business ,Ultrasonography - Published
- 2001
40. Successful Management of an Intramural Cervical Ectopic Pregnancy
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M. Singh, Samuel C. Johnson, R. Roberts, T. Woodard, and Valerie I. Shavell
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medicine.medical_specialty ,Ectopic pregnancy ,business.industry ,Obstetrics ,Obstetrics and Gynecology ,Medicine ,business ,medicine.disease - Published
- 2011
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41. Factors influencing fine-needle aspiration cytology in the management of recurrent gynecologic malignancies
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Eva M. Wojcik, Samuel C. Johnson, Suzanne M. Selvaggi, Susan S. Martier, and Joel W. Ager
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Target lesion ,Adult ,medicine.medical_specialty ,Genital Neoplasms, Female ,Uterine Cervical Neoplasms ,Sensitivity and Specificity ,Vulva ,Cytology ,Biopsy ,medicine ,Humans ,Stage (cooking) ,Cervix ,Aged ,Neoplasm Staging ,Aged, 80 and over ,Ovarian Neoplasms ,medicine.diagnostic_test ,Vulvar Neoplasms ,business.industry ,Biopsy, Needle ,Obstetrics and Gynecology ,Middle Aged ,Primary Neoplasm ,Surgery ,Endometrial Neoplasms ,medicine.anatomical_structure ,Oncology ,Genital neoplasm ,Female ,Radiology ,Neoplasm Recurrence, Local ,business - Abstract
Over a period of 6.5 years (January 1983 through August 1989) 124 fine-needle aspirations (FNAs) were performed on 95 patients with prior documented primary malignancies of the cervix, ovary, endometrium, and vulva. The significance of clinicopathologic factors which influenced the FNA results was analyzed by statistical methods. The factors studied included the initial patient clinical stage, the time interval between staging and disease recurrence, the treatment modalities, the neoplasm type, the aspiration site, the target lesion size, and the type of radiologic guidance. Primary aspiration sites were pelvic wall and organs (40%), lymph nodes (36%), and liver (21%); 64% were positive, 5% suspicious, 15% negative, and 16% unsatisfactory. The specificity was 100%; sensitivity, 96.3%; predictive value of a positive test, 100%; and predictive value of a negative test, 84.2%. Statistically significant clinicopathologic factors which influenced the FNA results included the target lesion size (P = 0.026) and the aspiration site (P = 0.033). The primary neoplasm type, the time interval between staging and disease recurrence, the initial patient clinical stage, the treatment modalities, and the type of radiologic guidance were not statistically significant. FNA is a reliable procedure in the management of gynecologic malignancy and its results are influenced by clinicopathologic factors.
- Published
- 1992
42. Instrumentation And Calibration Of Track And Field Starting Blocks For The Measurement Of Kinetic Data
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David W. Bacharach, Samuel C. Johnson, and Glenn M. Street
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Calibration (statistics) ,Environmental science ,Physical Therapy, Sports Therapy and Rehabilitation ,Orthopedics and Sports Medicine ,Instrumentation (computer programming) ,Kinetic energy ,Remote sensing - Published
- 2009
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43. Europlant revisited
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F.Newton Parks and Samuel C. Johnson
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Marketing ,Pride ,media_common.quotation_subject ,Control (management) ,Business environment ,Distribution system ,Economics ,Production (economics) ,Business and International Management ,Sales management ,Architecture ,Projection (set theory) ,media_common - Abstract
A five-year sales projection in 1961 showed considerable growth potential for S. C. Johnson & Son's European operations. After considering several alternatives, and keeping in mind the changing business environment, the firm decided to build a single facility—Europlant—to supply the. EEC market. Accordingly, a uniquely designed plant was constructed in the Netherlands How has Europlant fared since its opening. in 1964? There were, of course, some early problems. With these overcome, Johnson's EEC sales went on to exceed the planning forecasts. A key feature in Europlant is a production. planning control and distribution system. linked to a computer. The labor climate is sound, and the. striking architecture is a source of pride to both company and community.
- Published
- 1969
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44. How common is the common market?
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John B. Rhodes, Samuel C. Johnson, and F.Newton Parks
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Marketing ,Market economy ,Business ,Single market ,Business and International Management - Published
- 1963
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45. Ultrafast Optical Switching and Power Limiting in Intersubband Polaritonic Metasurfaces
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Samuel C. Johnson, Mikhail A. Belkin, Sander A. Mann, N. Nookala, Ahmed Mekkawy, Markus B. Raschke, Andrea Alù, Igal Brener, and John F. Klem
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Materials science ,business.industry ,Response time ,02 engineering and technology ,Limiting ,021001 nanoscience & nanotechnology ,01 natural sciences ,Optical switch ,010309 optics ,Resonator ,Nonlinear system ,0103 physical sciences ,Optoelectronics ,0210 nano-technology ,business ,Saturation (magnetic) ,Ultrashort pulse ,Plasmon - Abstract
We experimentally demonstrate a nonlinear metasurface comprising plasmonic resonators coupled to multi-quantum well transition. Due to MQW saturation, the metasurface provides a giant j(3) on the order of 3x10-13 m2/V2 with ~2 ps response time.
46. 'Karamu Album '62' [program]
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Bell, Nolan D.; Grimes, Charles; Pickett, Henry; White, Dianne; Dick, John; McMurray, Peggy; Martin, Patricia Ann; Price, Carolyn; Richards, Jean; Wilburn, Jonnie Belle; Moser, James; Strain, Frank; Caldwell, Harry D.; Levels, Servalin; Titus, Maxine; Morgan, Clyde; Grady, Virginia; Kleinfeld, George; White, Dianne; Wilson, LaMar; Finney, Henry, Jr.; Purcell, Robin; Yarnell, Gwen; Gordon, Michael; Ricks, Samuel C.; Johnson, Frank; Curtis, Patricia; Capko, John; McCann, Delores; Palivoda, Betty Lou; Faris, Judith, Karamu House, Bell, Nolan D.; Grimes, Charles; Pickett, Henry; White, Dianne; Dick, John; McMurray, Peggy; Martin, Patricia Ann; Price, Carolyn; Richards, Jean; Wilburn, Jonnie Belle; Moser, James; Strain, Frank; Caldwell, Harry D.; Levels, Servalin; Titus, Maxine; Morgan, Clyde; Grady, Virginia; Kleinfeld, George; White, Dianne; Wilson, LaMar; Finney, Henry, Jr.; Purcell, Robin; Yarnell, Gwen; Gordon, Michael; Ricks, Samuel C.; Johnson, Frank; Curtis, Patricia; Capko, John; McCann, Delores; Palivoda, Betty Lou; Faris, Judith, and Karamu House
- Abstract
Program of "Karamu Album '62", which ran from June 8-30, 1962. Performers: Nolan Bell, Charles Grimes, Henry Pickett, Dianne White, John Dick, Peggy McMurray, Patricia Martin, Carolyn Price, Jean Richards, Johnnie Wilburne, James Moser, Frank Strain, Harry Caldwell, Servalin, Levels, Maxine Titus, Clyde Morgan, Virginia Grady, George Kleinfeld, Dianne White, LeMar Wilson, Henry Finney, Robin Purcell, Gwen Yarnell, Michael Gordon, Samuel Ricks, Frank Johnson, Patricia Curtis, John Capko, Dolores McCann, Betty Lou Palivoda, and Judith Faris.
47. Individual, interpersonal, and community factors associated with health outcomes in patients with type 2 diabetes mellitus treated at federally qualified health centers.
- Author
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Ali AM, Cobran EK, and Young HN
- Abstract
Purpose: To examine factors of influence in diabetes management and their association with self-reported health outcomes in patients with type 2 diabetes treated at Federally Qualified Health Centers (FQHCs)., Methods: This cross-sectional study examined data from the 2014 Health Center Patient Survey (HCPS). Predictor variables were categorized across three levels of the National Institute on Minority Health and Health Disparities research framework. Outcome variables retrieved from HCPS included self-reports of blood glucose levels, and diabetes-related emergency department (ED)/hospital visits during past year., Results: A total of 936 patients with diabetes were included. Most (65%) participants received a diabetes self-management plan. During the previous year, 72% received > = 2 A1C checks, 52% reported high blood glucose levels, and 12% visited an ED/hospital. Multivariable results showed that insulin use and receiving a self-management plan were associated with high blood glucose levels and ED/hospital visits. Community factors of being unable to get medications and receiving a specialist foot exam were respectively associated with high blood glucose levels and ED/hospital visits., Conclusion: Different factors were associated with health outcomes in patients with diabetes treated at FQHCs. Identifying these factors can help with targeted screening and follow-up and assessing potential interventions to improve health outcomes., Supplementary Information: The online version contains supplementary material available at 10.1007/s40200-024-01388-5., Competing Interests: Competing interestsThe authors have no competing interests to declare that are relevant to the content of this article., (© The Author(s), under exclusive licence to Tehran University of Medical Sciences 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
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- 2024
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48. Who will have Sustainable Employment After a Back Injury? The Development of a Clinical Prediction Model in a Cohort of Injured Workers.
- Author
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Shearer HM, Côté P, Boyle E, Hayden JA, Frank J, and Johnson WG
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- Adult, Chi-Square Distribution, Female, Humans, Job Satisfaction, Male, Outcome Assessment, Health Care, Proportional Hazards Models, Prospective Studies, Time Factors, Workers' Compensation, Disability Evaluation, Low Back Pain rehabilitation, Occupational Injuries rehabilitation, Return to Work statistics & numerical data
- Abstract
Purpose Our objective was to develop a clinical prediction model to identify workers with sustainable employment following an episode of work-related low back pain (LBP). Methods We used data from a cohort study of injured workers with incident LBP claims in the USA to predict employment patterns 1 and 6 months following a workers' compensation claim. We developed three sequential models to determine the contribution of three domains of variables: (1) basic demographic/clinical variables; (2) health-related variables; and (3) work-related factors. Multivariable logistic regression was used to develop the predictive models. We constructed receiver operator curves and used the c-index to measure predictive accuracy. Results Seventy-nine percent and 77 % of workers had sustainable employment at 1 and 6 months, respectively. Sustainable employment at 1 month was predicted by initial back pain intensity, mental health-related quality of life, claim litigation and employer type (c-index = 0.77). At 6 months, sustainable employment was predicted by physical and mental health-related quality of life, claim litigation and employer type (c-index = 0.77). Adding health-related and work-related variables to models improved predictive accuracy by 8.5 and 10 % at 1 and 6 months respectively. Conclusion We developed clinically-relevant models to predict sustainable employment in injured workers who made a workers' compensation claim for LBP. Inquiring about back pain intensity, physical and mental health-related quality of life, claim litigation and employer type may be beneficial in developing programs of care. Our models need to be validated in other populations.
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- 2017
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49. Analysis of the effect of sentiment analysis on extracting adverse drug reactions from tweets and forum posts.
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Korkontzelos I, Nikfarjam A, Shardlow M, Sarker A, Ananiadou S, and Gonzalez GH
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- Humans, Internet, Public Health, Drug-Related Side Effects and Adverse Reactions, Pharmacovigilance, Social Media
- Abstract
Objective: The abundance of text available in social media and health related forums along with the rich expression of public opinion have recently attracted the interest of the public health community to use these sources for pharmacovigilance. Based on the intuition that patients post about Adverse Drug Reactions (ADRs) expressing negative sentiments, we investigate the effect of sentiment analysis features in locating ADR mentions., Methods: We enrich the feature space of a state-of-the-art ADR identification method with sentiment analysis features. Using a corpus of posts from the DailyStrength forum and tweets annotated for ADR and indication mentions, we evaluate the extent to which sentiment analysis features help in locating ADR mentions and distinguishing them from indication mentions., Results: Evaluation results show that sentiment analysis features marginally improve ADR identification in tweets and health related forum posts. Adding sentiment analysis features achieved a statistically significant F-measure increase from 72.14% to 73.22% in the Twitter part of an existing corpus using its original train/test split. Using stratified 10×10-fold cross-validation, statistically significant F-measure increases were shown in the DailyStrength part of the corpus, from 79.57% to 80.14%, and in the Twitter part of the corpus, from 66.91% to 69.16%. Moreover, sentiment analysis features are shown to reduce the number of ADRs being recognized as indications., Conclusion: This study shows that adding sentiment analysis features can marginally improve the performance of even a state-of-the-art ADR identification method. This improvement can be of use to pharmacovigilance practice, due to the rapidly increasing popularity of social media and health forums., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)
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- 2016
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50. Predictive modeling using a nationally representative database to identify patients at risk of developing microalbuminuria.
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Villa-Zapata L, Warholak T, Slack M, Malone D, Murcko A, Runger G, and Levengood M
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- Adult, Albuminuria blood, Albuminuria epidemiology, Databases, Factual, Female, Humans, Male, Middle Aged, Predictive Value of Tests, Prospective Studies, ROC Curve, Risk Factors, United States epidemiology, Albuminuria diagnosis, Biomarkers analysis, Models, Statistical, Nutrition Surveys methods, Risk Assessment methods
- Abstract
Purpose: Predictive models allow clinicians to identify higher- and lower-risk patients and make targeted treatment decisions. Microalbuminuria (MA) is a condition whose presence is understood to be an early marker for cardiovascular disease. The aims of this study were to develop a patient data-driven predictive model and a risk-score assessment to improve the identification of MA., Methods: The 2007-2008 National Health and Nutrition Examination Survey (NHANES) was utilized to create a predictive model. The dataset was split into thirds; one-third was used to develop the model, while the other two-thirds were utilized for internal validation. The 2012-2013 NHANES was used as an external validation database. Multivariate logistic regression was performed to create the model. Performance was evaluated using three criteria: (1) receiver operating characteristic curves; (2) pseudo-R (2) values; and (3) goodness of fit (Hosmer-Lemeshow). The model was then used to develop a risk-score chart., Results: A model was developed using variables for which there was a significant relationship. Variables included were systolic blood pressure, fasting glucose, C-reactive protein, blood urea nitrogen, and alcohol consumption. The model performed well, and no significant differences were observed when utilized in the validation datasets. A risk score was developed, and the probability of developing MA for each score was calculated., Conclusion: The predictive model provides new evidence about variables related with MA and may be used by clinicians to identify at-risk patients and to tailor treatment. The risk score developed may allow clinicians to measure a patient's MA risk.
- Published
- 2016
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