Article
Engineering, Electrical & Electronic
Hui Li, Wenrui Zheng, Qi Wu, Guo-Lin Liu
Summary: In this article, a pattern synthesis methodology for lossy antennas is proposed based on N-port characteristic mode analysis (CMA), with the radiation efficiency of the antenna guaranteed at the same time. Reactive loads are chosen as physical implementations. The method is applied to an arm-worn smartwatch antenna operating at GPS L1 band, which aims at radiating toward the sky direction for reliable link with satellites. The power radiated toward the target area has been increased by more than 40% compared with the original design, and the prototype of the proposed antenna has been fabricated and measured, which showed similar performances to the simulated one both in free space and in the arm-worn scenario.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Xiaoming Chen, Ming-Chun Tang, Dajiang Li, Mei Li
Summary: This paper presents the design and optimization of a flexible, bandwidth-enhanced, electrically small, electric near-field resonant parasitic (NFRP) filtering antenna. By adjusting the relative position of the NFRP element and the driven dipole, the antenna achieves excellent bandpass-filtering response and enhanced bandwidth. Experimental results confirm the stable performance of the antenna under different bending conditions.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Astronomy & Astrophysics
Jonathan Wernersson, Jochen Zahn
Summary: The study explores the impact of boundary conditions on vacuum polarization for charged scalar fields in two-dimensional space-time. It is found that both Dirichlet and Neumann boundary conditions result in screening effects. The vacuum polarization charge density vanishes at the boundary under Dirichlet conditions, while reaching its maximum under Neumann conditions. At a critical field strength, the vacuum polarization diverges for Neumann boundary conditions due to the instability of the lowest energy mode in the presence of an external field.
Article
Engineering, Electrical & Electronic
Ruizhi Liu, Ke Wu
Summary: Electromagnetic waves are widely used in modern communication systems, but traditional electromagnetic circuits may encounter issues in large-scale systems. Therefore, a new method based on wave or field interference is proposed to achieve interaction among devices. This method can spatially accomplish signal processing and has universal applicability to various physical wave devices and systems.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Hamid Reza Behjoo, Abbas Pirhadi, Reza Asvadi
Summary: This article proposes an efficient method that uses information-theoretic tools to determine the minimum number of samples and their locations for measuring the spherical near-field of antennas. The study investigates spherical harmonics from an information-theoretic perspective and provides a validation tool for assessing the ability of a sampling scheme to recover antenna characteristics. An optimum sampling scheme is proposed by clustering the energy of vector spherical harmonics using the frame theory, resulting in a highly efficient measurement procedure.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Miloslav Capek, Lukas Jelinek, Michal Masek
Summary: This study focuses on a numerically effective description of the total active reflection coefficient and realized gain for multiport antennas, taking into account material losses. The approach is based on operators represented in an entire-domain port-mode basis, with matrices of small dimensions. Optimal excitation and matching conditions are investigated, along with solving the combinatorial problem of optimal ports' placement and feeding synthesis. Numerical examples highlight the advantages of the proposed method, which can be easily implemented in existing electromagnetic simulators.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Astronomy & Astrophysics
Cristina Manuel, Juan M. Torres-Rincon
Summary: The study investigates the impact of a small fermion mass in the formulation of the on-shell effective field theory (OSEFT) and the subsequent derivation of small mass corrections to the chiral kinetic theory. It is found that in the presence of mass corrections, tensorial components are required in addition to vectorial components, while scalar components strictly vanish in OSEFT. Furthermore, the study reveals that up to second order in the energy expansion, vectorial and tensorial components are decoupled and follow the same dispersion law and transport equation based on their respective chirality.
Article
Mechanics
Yang Shi, Jin Xu, Junjie Ye
Summary: This paper designs a new acoustic-actuated antenna using embedded magnetoelectric (ME) composites, which improve the radiations of ME antennas through enhanced strain transfer. The performance of the ME antenna is evaluated using a multiphysics finite element method. Three optimum schemes are proposed for improving the ME antenna and are verified by simulation results. The embedded ME composite shows effective improvement in electromagnetic radiations by changing its sizes or configuration.
COMPOSITE STRUCTURES
(2023)
Article
Engineering, Electrical & Electronic
Hailun Wu, Maryam Ravan, Reza K. Amineh
Summary: Holographic microwave imaging is a fast and robust technique adapted for near-field applications like biomedical imaging and nondestructive testing. Antenna arrays are utilized to expedite data acquisition along the azimuthal direction, while different holographic imaging approaches are evaluated to deal with limited and nonuniform samples. The system is made low-cost and portable by using off-the-shelf components for constructing a data acquisition system, with simulation and experimental studies conducted to validate its performance.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2021)
Review
Physics, Multidisciplinary
Marcela Pelaez, Urko Reinosa, Julien Serreau, Matthieu Tissier, Nicolas Wschebor
Summary: Lattice simulations in the Landau gauge have shown that the coupling constant in the QCD sector remains finite and moderate at all scales, while the gluon propagator reaches a finite nonzero value at vanishing momentum. Studies have successfully described infrared QCD dynamics using the perturbative Curci-Ferrari model, with calculations showing good agreement with lattice simulations. The approach has also been applied to scenarios with dynamical quarks, showing controlled approximation schemes can account for chiral symmetry breaking. Applications to nonzero temperature and chemical potential have also been explored.
REPORTS ON PROGRESS IN PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Yang Mi, Jin Deng, Xiaomin Wang, Shunfu Lin, Xiangjing Su, Yang Fu
Summary: A multiagent distributed secondary control strategy is proposed to manage the energy storage system (ESS) with lossy communication networks in a DC microgrid. This strategy includes the construction of a multiagent dynamic-tracking consensus protocol (DCP) based on a random packet loss model, the design of an adaptive current sharing algorithm (ACSA) to balance the state of charge (SoC), and the proposal of a data-driven model-free adaptive control (MFAC) scheme for accurate voltage tracking and current sharing. Real-time simulation tests are conducted to verify the effectiveness of the designed control strategy, showing favorable capabilities in current sharing, voltage regulation, and robustness to communication packet loss and faults.
IEEE TRANSACTIONS ON SMART GRID
(2023)
Article
Engineering, Electrical & Electronic
Alessandro Felaco, Kamil Yavuz Kapusuz, Hendrik Rogier, Dries Vande Ginste
Summary: A novel method is proposed to accurately determine the operational range of an on-body, passive UHF RFID system operating in the radiative near field based on its far-field radiation patterns. By combining the new algorithm with the simulated or measured stand-alone far-field radiation patterns of the on-body RFID system, a comprehensive and accurate range determination is obtained. The accuracy and improved speed of the novel technique are demonstrated compared to commercial software tools and measurements.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Shang Guo, Deshuang Zhao, Bing-Zhong Wang
Summary: This paper presents a novel optimization method to quickly synthesize the uniform near fields of irregular arrays by significantly reducing the optimizing dimension. The proposed method uses smooth reference masks (SRMs) as the optimization parameters instead of the direct element excitations, making the synthesis much more efficient and faster.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2022)
Article
Microscopy
Guangbin Dai, Jie Wang, Xiaoxuan Zhang, Tianying Chang, Hong-Liang Cui
Summary: This study introduces a scattering-type scanning near-field microscope operating in the low terahertz band for nanoscopic investigations of sample surfaces and interfaces in the microwave and millimeter wave bands. By employing a nano-tip antenna and subharmonic mixer receiver with demodulation algorithms, high-resolution amplitude and phase images were achieved while scanning an Au-Si step structure, demonstrating the potential of this new instrument for micro/nano-resolution studies in the millimeter wave band.
Article
Optics
Y. U. A. N. S. H. E. N. G. Shi, K. A. N. G. Ouyang, W. U. Ren, W. E. I. M. I. N. G. LI, M. E. N. G. Cao, Z. H. E. N. G. H. U. Xue, M. E. N. G. Shi
Summary: Current near-field antenna measurement methods based on metal probes have limitations in accuracy and optimization due to their drawbacks such as large volume, metal reflection/interference, and complex circuit signal processing. This study proposes a novel method using Rydberg atoms in near-field antenna measurement, which offers higher accuracy due to their traceability to electric field. The method replaces the metal probe with Rydberg atoms contained in a vapor cell, achieving accurate amplitude and phase measurements of a 2.389 GHz signal.
Article
Rheumatology
Mercedes E. Quinones, Joyce K. Joseph, Sharon Dowell, Hans J. Moore, Pamela E. Karasik, Gregg C. Fonarow, Ross D. Fletcher, Yan Cheng, Qing Zeng-Treitler, Cherinne Arundel, Angelike P. Liappis, Helen M. Sheriff, Sijian Zhang, Daniel D. Taub, Michael S. Heimall, Charles Faselis, Gail S. Kerr, Ali Ahmed
Summary: This study examined the long-term risk of hydroxychloroquine use in patients with rheumatoid arthritis. The results showed that there was no association between hydroxychloroquine use and LQTS risk during the first 2 years of therapy. However, the risk increased significantly after 5 years of treatment. Nevertheless, the overall risk was low and attenuated with longer follow-up. These findings support the long-term safety of hydroxychloroquine in patients with rheumatoid arthritis.
ARTHRITIS CARE & RESEARCH
(2023)
Article
Cardiac & Cardiovascular Systems
Elizabeth Bierbower, Nayrana Griffith, Venkatesh K. Raman, Vijaywant Brar, Jeffrey Roseman, Prakash Deedwania, Gregg C. Fonarow, Richard M. Allman, Charles Faselis, Sijian Zhang, George Howard, Ali Ahmed, Phillip H. Lam
Summary: Heart failure (HF) is a risk factor for incident stroke, and the time to first stroke is shorter in older adults with HF. However, this extra risk appears to be primarily mediated by four cardiovascular diseases that are also risk factors for HF. These findings highlight the importance of primary prevention of these HF risk factors to reduce the extra risk of stroke in HF patients.
AMERICAN JOURNAL OF CARDIOLOGY
(2023)
Article
Health Care Sciences & Services
Yijun Shao, Ali Ahmed, Edward Y. Zamrini, Yan Cheng, Joseph L. Goulet, Qing Zeng-Treitler
Summary: Deep neural network (DNN) is a powerful technology used in disease risk prediction models. We developed a novel method called interaction scores for measuring the covariate interactions captured by DNN models. The method is model-agnostic and can be applied to other types of machine learning models.
JOURNAL OF PERSONALIZED MEDICINE
(2023)
Article
Clinical Neurology
Yan Cheng, Edward Zamrini, Charles Faselis, Douglas Redd, Yijun Shao, Charity J. Morgan, Helen M. Sheriff, Ali Ahmed, Peter Kokkinos, Qing Zeng-Treitler
Summary: This study found that cardiorespiratory fitness is associated with the incidence of Alzheimer's disease and related dementias. Moderate and high levels of cardiorespiratory fitness are related to a lower risk of dementia.
ALZHEIMERS & DEMENTIA
(2023)
Article
Pharmacology & Pharmacy
Jay Patel, Negin Rassekh, Gregg C. Fonarow, Prakash Deedwania, Farooq H. Sheikh, Ali Ahmed, Phillip H. Lam
Summary: Guideline-directed medical therapy (GDMT) is the cornerstone of pharmacological treatment for patients with heart failure with reduced ejection fraction (HFrEF) and includes four main drug classes: renin-angiotensin system inhibitors, evidence-based beta-blockers, mineralocorticoid inhibitors, and sodium glucose cotransporter 2 inhibitors. The recommendation for GDMT use is based on multiple large randomized controlled trials that have shown improved clinical outcomes in HFrEF patients. However, there is underutilization of GDMT due to a lack of knowledge on how to initiate and titrate these medications safely and effectively. This review article aims to describe the different drug classes in GDMT and provide guidance on initiation and titration in both inpatient and outpatient settings.
Article
Cardiac & Cardiovascular Systems
Alexander Smith, Sant Kumar, Hans J. Moore, Ami E. Iskandrian, Navin C. Nanda, Venkatesh K. Raman, Steven Singh, Ross D. Fletcher, Prakash Deedwania, Gregg C. Fonarow, Michael D. Greenberg, Ali Ahmed, Phillip H. Lam
Summary: This study aimed to examine whether the effect of implantable cardioverter-defibrillators (ICDs) on mortality in heart failure patients varied based on the noninvasive imaging method used to measure left ventricular ejection fraction (LVEF). The study found that there was no evidence that the effect of ICD on mortality varied based on the imaging method used.
Article
Medicine, General & Internal
Mo-Kyung Sin, Yan Cheng, Jeffrey M. Roseman, Caitlin Latimer, Ali Ahmed, Edward Zamrini
Summary: This study focuses on the characteristics and predictors of resilience to cognitive impairment in individuals with neuropathological evidence of Alzheimer's disease (AD). The study found that resilience to cognitive impairment was uncommon in older adults with AD neuropathology. Older age, diuretic use, and APOE-e2 carrier status were independently associated with higher odds of the resilience phenotype.
JOURNAL OF CLINICAL MEDICINE
(2023)
Article
Medicine, General & Internal
Mo-Kyung Sin, Yan Cheng, Jeffrey M. Roseman, Edward Zamrini, Ali Ahmed
Summary: Cerebral microinfarcts are associated with cognitive impairment and dementia. Small vessel diseases such as cerebral arteriolosclerosis and cerebral amyloid angiopathy (CAA) have been found to be significantly correlated with the presence, numbers, and location (cortical and subcortical) of microinfarcts. However, the association with arteriolosclerosis is stronger than that with CAA.
JOURNAL OF CLINICAL MEDICINE
(2023)
Article
Medicine, General & Internal
Samir Patel, Phillip H. Lam, Evangelos I. Kanonidis, Amiya A. Ahmed, Venkatesh K. Raman, Wen-Chih Wu, Patrick Rossignol, Cherinne Arundel, Charles Faselis, Ioannis E. Kanonidis, Prakash Deedwania, Richard M. Allman, Farooq H. Sheikh, Gregg C. Fonarow, Bertram Pitt, Ali Ahmed
Summary: The study shows that renin-angiotensin system inhibitors are beneficial for patients with heart failure with reduced ejection fraction and advanced kidney disease. These drugs reduce the risk of heart failure readmission and all-cause mortality.
AMERICAN JOURNAL OF MEDICINE
(2023)
Article
Urology & Nephrology
Samir Patel, Eduardo Trujillo A. Rivera, Venkatesh K. Raman, Charles Faselis, Virginia Wang, Jeffrey C. Fink, Jeffrey M. Roseman, Charity J. Morgan, Sijian Zhang, Helen M. Sheriff, Michael S. Heimall, Wen-Chih Wu, Qing Zeng-Treitler, Ali Ahmed
Summary: This study examined the impact of the COVID-19 pandemic on the delivery of maintenance hemodialysis treatment and death rates in patients with end-stage kidney disease (ESKD) in Veterans Health Administration (VHA) facilities. The findings suggest that there was no disruption in the delivery of maintenance hemodialysis treatment during the pandemic, and the modest increase in death rates is unlikely to be due to missed dialysis.
AMERICAN JOURNAL OF NEPHROLOGY
(2023)
Article
Geriatrics & Gerontology
Mo-Kyung Sin, Jung-Ah Lee, Patrick J. M. Murphy, Charles Faselis, Ali Ahmed
Summary: Aging-associated upper extremity weakness is associated with adverse health outcomes in older adults. However, the association between impaired upper extremity function and cause-specific mortality is less known. This study found that upper extremity weakness is weakly associated with all-cause mortality, primarily driven by a higher risk of non-cardiovascular mortality.
ARCHIVES OF GERONTOLOGY AND GERIATRICS
(2023)
Article
Health Care Sciences & Services
Yijun Shao, Yan Cheng, Stuart J. Nelson, Peter Kokkinos, Edward Y. Zamrini, Ali Ahmed, Qing Zeng-Treitler
Summary: Transformer is a cutting-edge deep neural network architecture that has revolutionized natural language processing. To adapt Transformer to the healthcare domain, a new DNN architecture called Hybrid Value-Aware Transformer (HVAT) has been designed, which can effectively learn from both longitudinal and non-longitudinal clinical data. HVAT is unique in its ability to incorporate numerical values associated with clinical codes/concepts and utilize a flexible longitudinal data representation. A prototype HVAT model trained on a case-control dataset achieved high performance in predicting Alzheimer's disease and related dementias, demonstrating the potential of HVAT for clinical data learning tasks.
JOURNAL OF PERSONALIZED MEDICINE
(2023)
Meeting Abstract
Cardiac & Cardiovascular Systems
Samir Patel, Wen-Chih Hank Wu, Sijian Zhang, Venkatesh K. Raman, Prakash C. Deedwania, Paul A. Heidenreich, Jeffrey Jeffrey, Craig Fink, Charles Faselis, Phillip Hong Lam, Helen Sheriff, Gregg C. Fonarow, Qing Zeng, Ali Ahmed
JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY
(2023)
Meeting Abstract
Cardiac & Cardiovascular Systems
Charles Faselis, Phillip Hong Lam, Prakash C. Deedwania, Ioannis Kanonidis, Evangelos Kanonidis, Amiya Ahmed, Samir Patel, Venkatesh K. Raman, Wen-Chih Wu, Michael Doumas, Richard M. Allman, Gregg C. Fonarow, Ali Ahmed
JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Behrooz Rezvani, Babak Hassibi, Fredrik Brannstrom, Majid Manteghi