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CT Thresholds for Spinal Bone Mineral Attenuation to Prioritize Eligible Older Women for Osteoporosis Screening

Open Journal of Radiology 2024年第2期14卷 92-101页

作者： Seo Yeon K. Orite Bryn Higuchi hyo-chun yoon Lana H. Gimber St. Elizabeths Medical Center Brighton MA USA University of California Irvine CA USA Kaiser Permanente Division of Research Oakland CA USA Department of Diagnostic Imaging Hawaii Permanente Medical Group Honolulu HI USA

Introduction: Computed tomography (CT) measurements of bone mineral attenuation may be a useful means to identify older women who should be prioritized for bone mineral density screening. Methods: We compared bone mineral attenuation as measured in the L1 vertebra of CT studies to the results of dual-energy x-ray absorptiometry (DEXA) studies to determine what CT attenuation thresholds might yield a reasonable combination of sensitivity and specificity for the detection of osteoporosis. The study was limited to women between the ages of 65 and 75 years who had a DEXA study and a CT that included the L1 or adjacent vertebra performed within 3 years of the DEXA study. Results: There were 1226 women in this study, of whom 452 (38%) had osteoporosis based on a T-score ≤ −2.5 by DEXA. There were 830 CT studies performed with contrast and 396 studies which were performed without contrast. There was a statistically significant difference in the mean HU of those studies performed without contrast compared to those with contrast (unenhanced mean 103 HU versus 125 HU, p < 0.001). Different CT attenuation thresholds provided the most appropriate combination of sensitivity and specificity for the detection of osteoporosis when comparing CT studies performed without or with IV contrast and when all the CT data were used in aggregate. Conclusion: Different thresholds appear necessary when using the mean CT vertebral attenuation to identify older women for preferential referral for DEXA studies.

关键词： Osteoporosis Bone Mineral Attenuation CT Threshold

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Efficacy of adjuvant mitomycin-C and triamcinoloneimpregnated nasal packing for endoscopic dacryocystorhinostomy

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International Journal of Ophthalmology(English edition) 2024年第3期17卷 480-484页

作者： Sang yoon Kim Christopher B Chambers Jung hyo Ahn Department of Ophthalmology Pusan National University Yangsan HospitalPusan National University School of MedicineResearch Institute for Convergence of Biomedical Science and TechnologyYangsanGyeongnam 50612Republic of Korea Department of Ophthalmology Harborview Medical CenterUniversity of Washington MedicineSeattleWashington 98109USA

●AIM:To compare the success rate and complications of adjuvant use of mitomycin C and triamcinoloneimpregnated biodegradable nasal packing(TABP)in endoscopic dacryocystorhinostomy(DCR).And to evaluate the efficacy of combining intraoperative mitomycin C and TABP for endoscopic DCR.●METHODS:A total of 198 eyes of 148 patients who underwent endoscopic DCR for acquired nasolacrimal duct obstruction were retrospectively *** patients were randomly divided into three groups:Group A included patients treated without intraoperative mitomycin C but with TABP,Group B included patients treated without triamcinolone but with intraoperative mitomycin C and normal saline-impregnated nasal packing,and Group C included patients treated with intraoperative mitomycin C and TABP.●RESULTS:The results revealed no significant difference in the overall success rates between Groups A(86.8%)and B(89.2%;P=0.377).However,Group C(97.5%)showed a significantly higher overall success rate than Groups A and *** incidence of granulomas was significantly lower in group C(5%)than in Groups A(20.8%)and B(15.2%;P=0.009).Other complications,such as crust,synechiae,and revision surgery,did not differ significantly among the three groups.●CONCLUSION:The combination of intraoperative mitomycin C and TABP effectively prevents granulomas and enhances surgical success ***,there is no statistically significant difference observed between the use of mitomycin C or TABP alone.

关键词： dacryocystorhinostomy endoscopic mitomycin C triamcinolone biodegradable

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Fracture Rate and Serious Complications of Vena Cava Filters

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Open Journal of Radiology 2013年第2期3卷 85-90页

作者： Myles M. Mitsunaga hyo-chun yoon John A. Burns School of Medicine University of Hawaii Honolulu USA Kaiser Foundation Hospital Honolulu USA

Purpose: To retrospectively evaluate the prevalence of fracture and fragment embolization of inferior vena cava (IVC) filters. Methods: Electronic medical records and imaging studies of all Kaiser Permanente patients who received IVC filters from August 2000 until August 2010 were retrospectively reviewed for filter complications. Results: 283 patients received an IVC filter during the study period. 143 patients were deceased, while 140 are living. Among deceased patients, the average age at the time of death was 69.8 ± 15.3 [range: 24.7 - 99.2] years;55.9% were men;the mean implantation-to-image time was 13.6 ± 20.6 [range: 0 - 92.4] months, and there were no reported major complications attributable to filter migration or fracture at a mean of 16.8 ± 24.8 [range: 0 - 119.6] months following implantation. One of 14 (7.1%) G2 filters perforated the aorta, which already had a stent graft in place. Among those patients still living, the average age was 67.3 ± 15.2 [range: 15.2 - 97.3] years, 47.1% were men, the mean implantation-to-image time was 33.3 ± 36.5 [range: 0.1-141.7] months, and there were no reported major complications at a mean of 35.3 ± 36.5 [range: 0 - 141.7] months following implantation. Three of 60 (5.0%) Trapease filters were found to have at least 1 strut fracture. There were no cases of filter migration or fragment embolization. The overall fracture rate of all filters with an implantation-to-image-time greater than two years (mean implantation-to-image time 4.7 ± 2.7 [range: 2.0 - 11.8] years) was 3 of 67 (4.5%). Bard G2 and G2X filters had a 0% fracture and embolization rate at a mean of 19.0 ± 16.6 [range: 0.07 - 49.5] months after implantation. Conclusions: IVC filters, regardless of type, have a low prevalence of fracture and we found no cases of fragment embolization.

关键词： Venous Thromboembolism Inferior Vena Cava IVC Filters Pulmonary Embolism Deep Venous Thrombosis Complications

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Avoiding Unnecessary Pulmonary CT Angiography by Using a Combination of Clinical Criteria and D-Dimer Thresholds

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Open Journal of Radiology 2013年第2期3卷 78-84页

作者： Lana Hirai Gimber Jamie Leong Lauren Todoki hyo-chun yoon Department of Diagnostic Imaging Kaiser Foundation Hospital Los Angeles USA Department of Medical Imaging University of Arizona Tucson USA

Objective: To evaluate what specific combination of clinical criteria and d-dimer values may yield at least a 10% positive pulmonary embolism (PE) rate in patients undergoing pulmonary CT angiography (CTA). Materials and Methods: Retrospective review of all patients presenting to the Emergency Department with possible PE who underwent pulmonary CTA and had a d-dimer drawn. Wells scores were retrospectively assigned based on data gathered through medical records. Results: During a 29-month period, 1110 patients underwent pulmonary CTA. Of these, 773 also had a d-dimer drawn. These subjects were stratified based on serum d-dimer levels into negative (≤4 μg/ml), nonpositive (0.41 - 1.0 μg/ml), or positive (>1.0 μg/ml) d-dimer categories. The prevalence of positive CTA studies was >10% only in the positive d-dimer group. Subjects were also stratified based on their Wells score into three clinical categories: low (score 2), intermediate (score = 2 - 6), and high risk of pulmonary embolism (score > 6). The prevalence of positive CTA was > 10% only in the group of subjects with high clinical risk. When stratified according to both Wells criteria and d-dimer, only those patients with intermediate or high clinical risk combined with a positive d-dimer (>1.0 μg/ml) had a prevalence of positive pulmonary CTA > 10%. By limiting the use of CTA studies to those patients with positive d-dimer values or high clinical risk, 438 (55.4%) patients could have avoided CTA imaging. Conclusion: Utilizing CTA only in patients suspected of PE with a combination of high clinical risk based on a Wells criteria threshold score > 6 and a serum d-dimer cutoff of 1 μg/ml would increase the prevalence of positive pulmonary CTA studies above 10% and avoid a large number of CTA imaging studies.

关键词： Pulmonary CT Angiography Pulmonary Embolism Wells Scores D-Dimer Values

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A Dynamical System-Based Framework for Dimension Reduction

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Communications on Applied Mathematics and Computation 2024年第2期6卷 757-789页

作者： Ryeongkyung yoon Braxton Ostin Department of Mathematics University of UtahSalt Lake CityUTUSA

We propose a novel framework for learning a low-dimensional representation of data based on nonlinear dynamical systems,which we call the dynamical dimension reduction(DDR).In the DDR model,each point is evolved via a nonlinear flow towards a lower-dimensional subspace;the projection onto the subspace gives the low-dimensional *** the model involves identifying the nonlinear flow and the *** the equation discovery method,we represent the vector field that defines the flow using a linear combination of dictionary elements,where each element is a pre-specified linear/nonlinear candidate function.A regularization term for the average total kinetic energy is also introduced and motivated by the optimal transport *** prove that the resulting optimization problem is well-posed and establish several properties of the DDR *** also show how the DDR method can be trained using a gradient-based optimization method,where the gradients are computed using the adjoint method from the optimal control *** DDR method is implemented and compared on synthetic and example data sets to other dimension reduction methods,including the PCA,t-SNE,and Umap.

关键词： Dimension reduction Equation discovery Dynamical systems Adjoint method Optimal transportation

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Negative Stiffness Mechanism on An Asymmetric Wave Energy Converter by Using A Weakly Nonlinear Potential Model

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China Ocean Engineering 2024年第4期38卷 689-700页

作者： Sunny Kumar POGULURI Dongeun KIM yoon Hyeok BAE Department of Ocean Engineering IIT MadrasChennaiIndia Multidisciplinary Graduate School Program for Wind Energy Jeju National UniversityJejuRepublic of Korea Mechanical and System Design Engineering Hongik UniversitySeoulRepublic of Korea

Salter's duck,an asymmetrical wave energy converter(WEC)device,showed high efficiency in extracting energy from 2D regular waves in the past;yet,challenges remain for fluctuating wave *** can potentially be addressed by adopting a negative stiffness mechanism(NSM)in WEC devices to enhance system efficiency,even in highly nonlinear and steep 3D waves.A weakly nonlinear model was developed which incorporated a nonlinear restoring moment and NSM into the linear formulations and was applied to an asymmetric WEC using a time domain potential flow *** model was initially validated by comparing it with published experimental and numerical computational fluid dynamics *** current results were in good agreement with the published *** was found that the energy extraction increased in the range of 6%to 17%during the evaluation of the effectiveness of the NSM in regular *** irregular wave conditions,specifically at the design wave conditions for the selected test site,the energy extraction increased by 2.4%,with annual energy production increments of approximately *** findings highlight the potential of NSM in enhancing the performance of asymmetric WEC devices,indicating more efficient energy extraction under various wave conditions.

关键词： asymmetric wave energy converter negative stiffness mechanism weakly nonlinear potential flow power

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100 W-class green hydrogen production from ammonia at a dual-layer electrode containing a Pt-Ir catalyst for an alkaline electrolytic process

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Journal of Energy Chemistry 2024年第6期93卷 352-360,I0009页

作者： Donghyun yoon Sunki chung Minjun Choi Eunhyeok Yang Jaeyoung Lee School of Earth Sciences and Environmental Engineering Gwangju Institute of Science and Technology(GIST)Gwangju 61005Republic of Korea International Future Research Center of Chemical Energy Storage and Conversion Processes GISTGwangju 61005Republic of Korea Ertl Center for Electrochemistry and Catalysis GISTGwangju 61005Republic of Korea TKG Huchems Co.Ltd 963Sangam-roYeosu-siJeollanam-do 59614Republic of Korea

Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen *** decomposition has recently been used for the conversion of ammonia to hydrogen and is regarded as a future technology for production of CO_(2)-free pure ***,a heterostructural Pt-Ir dual-layer electrode is developed and shown to achieve successful long-term operation in an ammonia electrolyzer with an anion exchange membrane(AEM).This electrolyzer consisted of eight membra ne electrode assemblies(MEAs)with a total geometric area of 200 cm~2 on the anode side,which resulted in a hydrogen production rate of 25 L h~(-1).We observed the degradation in MEA performance attributed to changes in the anode catalyst layer during hydrogen production via ammonia ***,we demonstrated the relationship between the ammonia oxidation reaction(AOR)and the oxygen evolution reaction(OER).

关键词： Ammonia oxidation Dual-layer catalyst Green hydrogen Electrolytic process Oxygen evolution reaction

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Modification strategies improving the electrochemical and structural stability of high-Ni cathode materials

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Journal of Energy Chemistry 2024年第9期96卷 185-205页

作者： yoon Bo Sim Hami Lee Junyoung Mun Ki Jae Kim Department of Energy Science Sungkyunkwan UniversitySuwon 16419Republic of Korea School of Advanced Materials Sciencend Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea SKKU Institute of Energy Sciencend Technology(SIEST) Sungkyunkwan UniversitySuwon 16419Republic of Korea

With the increasing spotlight in electric vehicles,there is a growing demand for high-energy-density batteries to enhance driving ***,several studies have been conducted on high-energy-density LiNi_(x)Co_(y)Mn_(z)O_(2)***,there is a limit to permanent performance deterioration because of side reactions caused by moisture in the atmosphere and continuous microcracks during cycling as the Ni content to express high energy increases and the content of Mn and Co that maintain structural and electrochemical stabilization *** direct modification of the surface and bulk regions aims to enhance the capacity and long-term performance of high-Ni cathode ***,an efficient modification requires a study based on a thorough understanding of the degradation mechanisms in the surface and bulk *** this review,a comprehensive analysis of various modifications,including doping,coating,concentration gradient,and single crystals,is conducted to solve degradation issues along with an analysis of the overall degradation mechanism occurring in high-Ni cathode *** also summarizes recent research developments related to the following modifications,aims to provide notable points and directions for post-studies,and provides valuable references for the commercialization of stable high-energy-density cathode materials.

关键词： High energy density High-Ni cathode materials Degradation Structural stability Lithium-ion battery

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Synaptic a-Si:H/a-Ga_(2)O_(3)phototransistor inspired by the phototaxis behavior of organisms with all-optical and all-electrical stimulation modes

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Nano Research 2024年第8期17卷 7631-7642页

作者： Youngbin yoon Youngki Kim Soowon Choi Jungdae Kwon Myunghun Shin School of Electronics and Information Engineering Korea Aerospace UniversityGoyang10540Republic of Korea Nano Materials Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Engineering Pusan National UniversityBusan 46241Republic of Korea

To improve neuromorphic computing performance,neuromorphic system components should mimic the behaviors of organic *** this study,a synaptic a-Si:H/a-Ga_(2)O_(3)phototransistor featuring all-optical and-electrical emulation is fabricated in a manner advantageous for complementary metal-oxide-semiconductor process *** phototransistor exhibits excitatory and inhibitory synaptic behaviors under stimulation by both optical and electrical *** mimics several essential synaptic functions,including excitatory postsynaptic current,inhibitory postsynaptic current,short-term memory,long-term memory,pairedpulse facilitation,and spike-timing-dependent *** optical and electrical modulation mechanisms are confirmed to arise from the a-Si:H/a-Ga_(2)O_(3)heterojunction structure and interface effects,and the device is shown to operate at low power in both optical and electrical *** all-optical weight modulation function is applied to the wavelength-differential behavior response of zebrafish,successfully mimicking the color perception process of the ***,to verify the translation of the optoelectrical-derived synaptic behaviors of the phototransistor into artificial neuromorphic computation,handwritten digit image recognition of the Modified National Institute of Standards and Technology dataset is performed by a convolutional neural network,with a demonstrated average learning accuracy of 98.46%.These findings verify the applicability of the synaptic a-Si:H/a-Ga_(2)O_(3)phototransistor in neuromorphic computing.

关键词： synaptic phototransistor artificial synapse phototaxis neuromorphic computing interface charge state optoelectronic synaptic device

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Advances in Wireless,Batteryless,Implantable Electronics for Real‑Time,Continuous Physiological Monitoring

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Nano-Micro Letters 2024年第3期16卷 254-302页

作者： Hyeonseok Kim Bruno Rigo Gabriella Wong yoon Jae Lee Woon‑Hong Yeo IEN Center for Wearable Intelligent Systems and Healthcare Georgia Institute of TechnologyAtlantaGA 30332USA George W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA 30332USA School of Electrical and Computer Engineering Georgia Institute of TechnologyAtlantaGA 30332USA Wallace H.Coulter Department of Biomedical Engineering Georgia Tech and Emory University School of MedicineAtlantaGA 30332USA Parker H.Petit Institute for Bioengineering and Biosciences Institute for MaterialsInstitute for Robotics and Intelligent MachinesGeorgia Institute of TechnologyAtlantaGA 30332USA

This review summarizes recent progress in developing wireless,batteryless,fully implantable biomedical devices for real-time continuous physiological signal monitoring,focusing on advancing human health *** considerations,such as biological constraints,energy sourcing,and wireless communication,are discussed in achieving the desired performance of the devices and enhanced interface with human *** addition,we review the recent achievements in materials used for developing implantable systems,emphasizing their importance in achieving multi-functionalities,biocompatibility,and *** wireless,batteryless devices offer minimally invasive device insertion to the body,enabling portable health monitoring and advanced disease ***,we summarize the most recent practical applications of advanced implantable devices for human health care,highlighting their potential for immediate commercialization and clinical uses.

关键词： Implantable electronics Biomedical systems Batteryless devices Wireless electronics Physiological signal monitoring

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