bluuebunny/crossref_metadata_2025_split huggingface dataset:
Management of delirium at an academic medical center: Plans for antipsychotic prescribing upon discharge
Authors: Halavonich Lauren , Robert Sophie , McGraw Dan , Weeda Erin , Mullinax Kristen , Bass Bailey 
Published: January 2020

Abstract

Introduction
Delirium is an acute, fluctuating change in mental status, often associated with behavioral manifestations such as agitation. Literature suggests that many patients who continue on antipsychotics for extended management of delirium are not provided instructions for discontinuation. However, there is a positive correlation between consult services and instructions for discontinuation. The objective of this study was to determine the frequency at which patients with delirium were prescribed an antipsychotic at hospital discharge and to characterize discharge antipsychotic prescribing for psychiatric consult and nonconsult cohorts.

Methods
This study was a retrospective chart review of adult patients with an International Classification of Diseases 10th revision code of delirium who received at least 1 dose of antipsychotic during their admission. Inclusion criteria were all patients aged 18 years or older with a diagnosis of or relating to delirium who were administered antipsychotics during their admission.

Results
A total of 152 patients were included, of which 43 received a psychiatric consult. Antipsychotics were prescribed at discharge for management of delirium for 52 (34.2%) of 152 total patients. More patients in the psychiatric consult cohort were discharged with an antipsychotic as compared to those in the nonconsult cohort (53.3% vs 26.6%, P =  .02).

Discussion
Compared to previous studies, patients in this retrospective review were more likely to be discharged on an antipsychotic that was initiated during admission for management of delirium. Findings from this study also align with prior research demonstrating a positive association between antipsychotic discharge instructions and specialty consult recommendations.
Mirtazapine's effect on the QT interval in medically hospitalized patients
Authors: Allen Nicholas D. , Leung Jonathan G. , Palmer Brian A. 
Published: January 2020

Abstract

Introduction
Mirtazapine is generally well tolerated in medically ill patients with and without formal psychiatric comorbidity to target sleep, appetite, nausea, and pain. However, there is little data regarding mirtazapine's potential to prolong the corrected QT interval (QTc) in this population.

Methods
From a retrospective cohort of patients hospitalized on a variety of medical units for whom a psychiatric consult recommended mirtazapine, electrocardiogram (ECG) data were extracted for ECGs obtained up to 3 days before and 6 days after the initial consult. Descriptive statistics were used to characterize the QTc changes and adverse cardiac outcomes, including incident ventricular tachycardia, torsades de pointes, and sudden cardiac death. Multiple linear regression models were completed to assess the effect of potential confounding variables on QTc changes.

Results
Complete premirtazapine and postmirtazapine ECG data were available for 61 patients, and the average change in QTc was –0.31 ms (SD = 36.62 ms). No incidental adverse cardiac outcomes were found. QTc changes were not significantly affected by patient age and sex, initial and maximum mirtazapine dose, days between ECGs, number of concomitant QTc prolonging medications, Charlson comorbidity scores, and electrolyte abnormalities. Due to incomplete potassium, magnesium, and ionized calcium data, electrolytes were excluded from the final regression model.

Discussion
Despite the limitations of this retrospective study, these data suggest that modest doses of mirtazapine may not significantly affect the QTc in medically ill patients. Retrospective cohorts are more feasibly analyzed, but prospective controlled trials could more systematically assess QTc changes with higher doses of mirtazapine in medical settings.
Coronary Microvascular Dysfunction Years After Cessation of Anabolic Androgenic Steroid Use
Authors: Bulut Yeliz , Rasmussen Jon Jarløv , Brandt-Jacobsen Niels , Frystyk Jan , Thevis Mario , Schou Morten , Gustafsson Finn , Hasbak Philip , Kistorp Caroline 
Published: December 2024

ImportanceLong-term use of anabolic androgenic steroids (AASs) is associated with a high risk of left ventricular hypertrophy, heart failure with reduced systolic function, and early sudden death, with the mechanism of progression being understudied. Early and persistent impaired myocardial microcirculation could be of clinical importance and a potential underlying mechanism of frequent and early cardiac disease among individuals with AAS use and a future potential target for intervention.ObjectiveTo investigate coronary microcirculation by measuring myocardial flow reserve (MFR) in men with current and former AAS use compared with controls with no prior AAS use, using cardiac rubidium 82 (82Rb) positron emission tomography/computed tomography (PET/CT).Design, Setting, and ParticipantsThis cross-sectional study included men involved in recreational strength training without established cardiovascular disease grouped according to their history of AAS use. The study was conducted November 24, 2021, to August 16, 2023.ExposureCardiac PET/CT with 82Rb was performed at rest and after adenosine-induced stress.Main Outcome and MeasureThe primary outcome of this study was the MFR among the study groups; a secondary outcome was the coronary calcium score. By definition, impaired myocardial microcirculation was determined using a cutoff of MFR less than 2, and subclinically impaired microcirculation was determined using a cutoff of MFR less than 2.5.ResultsA total of 90 men (32 with current AAS use, 31 with former AAS use, and 27 controls) were included. Mean (SD) age was 35.1 (8.7) years. Elapsed duration since AAS cessation was a geometric mean of 1.5 (95% CI, 0.9-2.5) years. Eighteen men (58.1%) with former use discontinued AAS use more than 1 year before enrollment. Impaired MFR was present in those with current (6 [18.8%]) and former (1 [3.2%]) use, whereas no impairment was observed among the controls (P = .02). Subclinically impaired MFR was higher among men with current (9 [28.1%]) and former (8 [25.8%]) AAS use than the controls (1 [3.7%]) (P = .02). In a multivariable logistic regression model among men with former AAS use, every doubling of the accumulated weekly duration of AAS use (log2) was independently associated with a factor 2 increase in the risk of impaired MFR less than 2.5 (odds ratio, 2.1; 95% CI, 1.03-4.35; P = .04).Conclusions and RelevanceIn this study, men with former AAS use displayed impaired MFR years after AAS cessation, suggesting impaired coronary microcirculation persists beyond active use.
Anechoic Chambers
Authors: Chung Boon‐Kuan 
Published: December 2024

Abstract
The geometric shape of the anechoic chamber can be optimized to achieve better performance. Microwave absorbers to be installed over the entire inner surfaces of the anechoic chamber must be properly selected. The selection criteria may include the reflectivity levels for normal and oblique incident angles, operating frequency, bandwidth, type of bulk materials, size, shape, weight, mechanical stability, mounting method, fire retardant, and lifespan. The anechoic chamber must be sufficiently large to provide the required dimensions of the quiet zone. Shielding enclosure is provided to prevent extraneous energy from masking measurements of the intended signals. Ventilation, access doors, lighting, cabling, and heating–ventilation–air conditioning (HVAC) will be incorporated in the design according to the operational purpose of the facility. Different construction methods will give rise to varying degrees of imperfection that determine the shielding effectiveness. The performance of the anechoic environment may be evaluated in terms of amplitude ripple and phase change across the quiet zone. There is much interest in trying to reduce the required investment in constructing an anechoic chamber while still maintaining adequate performance. With a suitable computer simulation tool, together with a reasonable absorber model, the design of anechoic chamber can be made more economical.
Application of Wavelets and Machine Learning Techniques to Electromagnetic Problems
Authors: Goswami Jaideva C. , Tentzeris Manos M. 
Published: December 2024

Abstract
In this article, we discuss some wavelet applications to electromagnetic problems, provide an overview of wavelet theory, solve integral equations developing from electromagnetic scattering and transmission‐line problems, and consider differential equations. Examples from geophysical applications are also included. Combined wavelet‐machine learning technique is presented for numerical modeling.
Dielectric Resonator Antennas
Authors: Yang Nan , Leung Kwok W. 
Published: December 2024

Abstract
Dielectric resonator (DR) antenna (DRA) has been studied for decades, for its compact size, various radiation modes and radiation patterns, high efficiency, high design flexibility, and so on. As a fabrication‐friendly shape, cylindrical DRA is investigated in this chapter. To begin, the fundamentals of cylindrical DRA have been introduced first, including its mode nomenclature, resonant frequency calculation, field distribution, and various excitation methods. Especially, two kinds of planar feeding methods for exciting TM modes of a cylindrical DRA were developed recently and introduced. Researchers all over the world are exploring the diversity potential of DRA, including pattern diversity. However, it can be found that the resonant frequencies of the and modes cannot coincide, implying there are theoretical limitations for pattern‐diversity designs using fundamental modes. In this chapter, two pattern‐diversity designs are presented with the fundamental modes. The first wideband design uses a cylindrical DRA with a centrally loaded high‐permittivity material. This kind of material can lengthen the electrical length of the mode and therefore lower its resonant frequency. At the same time, the resonant frequency of the mode can be affected little. This design features an overlapping impedance bandwidth of 23.6%. For the latter compact design, a meanderline‐loaded ring slot is employed to excite the mode. By lengthening the current paths on the ground plane with the meander lines, the resonant frequency of the mode can be reduced, whereas that of the mode can be found to be unchanged. This compact design has a volume of and a profile of , where is the resonant wavelength in the dielectric. Both of the designs have low envelope correlation coefficients (ECCs), proving to be good diversity antennas.
Fractal Antennas
Authors: Anguera Jaume , Puente Carles , Borja Carmen , Soler Jordi 
Published: December 2024

Abstract

The combination of fractal geometry with electromagnetic theory opens an interesting window for research to find new antenna designs and applications. Fractal antenna technology applications can be divided into six main groups:

Multifrequency: antenna elements, frequency‐selective surfaces (FSSs), and arrays.

Miniaturization: electrically small antennas, decoupling structures, and metamaterials.

High directivity radiating elements.

Low‐sidelobe arrays.

Undersampled arrays.

Fast computational methods.

This chapter reviews salient results of the work done in the fractal technology field covering the last six fields.
Frequency Selective Surfaces
Authors: Wu Te‐Kao 
Published: December 2024

Abstract
A summary description of frequency‐selective surface (FSS) is provided. Subjects covered include various kinds of FSS and characteristics, bandpass and bandstop FSS, aperture and patch element FSS, thin/thick‐screen FSS, FSS analysis techniques and design tools, dielectric loading effects, grating lobe and Wood's anomaly, as well as various FSS applications and developments. An FSS bibliography is also provided listing all the references necessary for further research on the subject of FSS.
Orthomode Transducers
Authors: Gentili Gian Guido , Nesti Renzo , Pelosi Giuseppe , Selleri Stefano 
Published: December 2024

Abstract
In the present work, orthomode transducers (OMTs) and polarizers are presented. First, field configurations and propagation properties in common waveguides, which are extensively used in OMTs and polarizers, are analyzed to provide the reader with the necessary background to understand both devices.
As a second step, some OMTs and polarizers are described in an attempt to highlight their electromagnetic features; this is not intended as a full review of all the known OMT and polarizer configurations, which is beyond the scope of this work, but to provide the reader with a basic knowledge of the principles of their operation. This is done by choosing a small, but representative, set of configurations largely used in practice that analyzed in depth, in the author's opinion, gives the reader a fundamental understanding and a broad knowledge of the argument.
Finally, three example designs of two OMTs and one polarizer are presented.
Radiowave Propagation Concepts
Authors: Yi Cheng , He Yaping , Wang Haiming 
Published: December 2024

Abstract
Although radiowaves also propagate in waveguides, cables, and transmission lines, the term radiowave propagation is used generally, and specifically in this chapter, for signal travel between a source and a receiver without guidance by such artificial devices. Examples of such systems are radio and television broadcasting, radio point‐to‐point communication, radar, radio navigation, and remote sensing. Much has been learned about radiowave propagation since Hertz first demonstrated wireless transmission from one room to another. Now, radiowave propagation is considered a moderately mature science, yet new understanding continues to emerge. This chapter presents an overview of radiowave propagation concepts.
An advantage of electronic communication is that an artificial link (e.g., transmission line, cable, or waveguide) is not necessarily required between the signal source and the receiver. Indeed, the term “wireless” is used in many parts of the world in preference to “radio,” and even in the United States, “wireless” is often used to describe commercial personal communication by radio. Although radiowaves also propagate in waveguides, cables, and transmission lines, the term “radiowave propagation” is used generally, and specifically in this chapter, for signal travel between a source and a receiver without guidance by such artificial devices. Examples of such systems are radio and television broadcasting, radio point‐to‐point communication, radar, radio navigation, and remote sensing.
The concept of radiowave propagation allows the division of the total system problem into three separate parts: the transmitter or signal source, the receiver, and propagation. Thus, propagation is defined as what happens between the source and the receiver. For this concept to be valid, the distances must be such that far‐field criteria for the antennas are satisfied; this allows separating antenna effects from propagation effects. In radar, two propagation paths are involved: from the transmitter to the target and from the target to the receiver.
Much has been learned about radiowave propagation since Hertz first demonstrated wireless transmission from one room to another. Now radiowave propagation is considered a moderately mature science, yet new understanding continues to emerge. This chapter presents an overview of radiowave propagation concepts. More detailed information will be found in articles on specific topics in radiowave propagation.
Reflector Antennas
Authors: Terada Marco A. B. 
Published: December 2024

Abstract
This chapter presents a glimpse into the universe of reflector antennas. The initial sections offer an overview of reflector antennas and their main applications at a level suitable for high school and lower‐division college students, as well as the basic principles necessary for the proper understanding of their functionality. The following sections present a more in‐depth treatment of the subject, including methodologies for analyzing and designing practical reflector systems. Finally, advanced topics covering the current state of the art within the field are discussed at a level targeting both graduate students and researchers, as well as the practicing engineer. An effort is made to illustrate the theory and discussions with examples of reflector antennas embedded in real‐world scenarios, from digital communication systems to astronomical measurements.
Spiral Antennas
Authors: Cencich Thomas , Samson Timothy 
Published: December 2024

Abstract

Spiral antennas were introduced in the mid‐1950s. They were the first antennas to exhibit uniform impedance and pattern performance over multioctave bandwidths. Spirals were the cornerstone and mathematical quintessence of a new concept in antenna theory termed
frequency‐independent antennas
. In this chapter, various aspects related to the analysis and design of spiral antennas are discussed. The theory of spiral operation, often referred to as
band theory
, is discussed. Also included are characteristic geometries and shapes including equiangular and Archimedean planar and conical spirals. Theoretical and practical aspects needed for successful design and understanding of spiral antennas are reviewed. Special attention is given to understanding the modal performance of multiarm spiral antennas and its importance to overall antenna characteristics, analysis theory, mode‐forming networks, multimode excitations, etc. Various feeding methods including infinite and tapered baluns, as well as coaxial bundles are described. Dual‐polarized spiral designs including inside/outside‐fed spirals and modulated armwidth (MAW) spirals, and bandwidths of various spiral geometries are discussed. The chapter also includes some aspects of spiral miniaturization; discussions of the challenges of nondissipative cavity backing, utilization of spirals as reflector feeds, the modal decomposition technique; and an overview of numerical methods utilized for successful design of spiral antennas. The chapter is organized into several sections, each devoted to a separate topic, with illustrations and tables utilized for further clarification and demonstration of discussed concepts.
Submarine Antennas
Authors: Rivera David F. , Bansal Rajeev 
Published: December 2024

Abstract
The design of a submarine antenna differs from its commercial counterpart in two important respects. The antenna must be (1) physically smaller yet able be accommodate numerous electrical functions simultaneously and (2) rugged enough to survive the effects of an unforgiving ocean environment. The successful design of an antenna for such a demanding application is thus an outgrowth of cross‐disciplinary efforts from diverse fields such as materials science, electrochemistry, fluid mechanics, and other allied areas. This article briefly summarizes those aspects of submarine antenna design of importance to the engineer, with an emphasis on its implementation above, beneath, or on the sea surface.
Quadrature Phase Shift Keying (QPSK) with Applications to Six‐Port Technology
Authors: Tatu Serioja O. , Bosisio Renato G. 
Published: December 2024

Abstract
Quadrature phase shift keying (QPSK) is a modulation technique used for sending data over radio or cable networks.
This article presents in detail the QPSK principle, as well as modulators and demodulators, using the conventional approach. A new concept to modulate or demodulate a QPSK signal using the six‐port circuit at microwave/millimeter‐wave frequencies is also presented.
The coherent carrier‐recovery circuit for the demodulation of QPSK signals is an important aspect to be considered. Three regeneration schemes (Costas loop, multiplication loop, and reverse‐modulation loop) are presented.
The probability of error for QPSK in the presence of noise is derived using the equations of I‐ and Q‐demodulated signals.
Nonlinear Circuit Analysis
Authors: Suárez Almudena 
Published: December 2024

Abstract
The reliable prediction of the circuit response prior to manufacturing demands realistic element models and accurate analysis methods. This analysis has added difficulties in the case of nonlinear circuits, such as those based on transistors and diodes, in which the superposition principle does not hold. This gives rise to a dependence of the circuit response on the input amplitude and the generation of harmonic and intermodulation frequencies, among other phenomena. The special characteristics of nonlinear circuits are often undesired, but they also make them the only choice to obtain essential functions such as frequency mixing, frequency multiplication, oscillation, and frequency division. This article presents a detailed summary of numerical simulation methods in both the time and frequency domains, highlighting their advantages, limitations, and providing application examples.
Phase‐Locked Loops
Authors: Kolumbán Géza 
Published: December 2024

Abstract
Phase‐locked loops (PLLs) are used everywhere in information and communication technology (ICT) and measurement engineering to implement various applications such as modulators and demodulators, frequency synthesizers, and clock recovery circuits, just to mention a few examples. Depending on the operation principle of their building blocks, analog, digital, and hybrid‐type PLLs are distinguished. This article starts with the analog PLL theory in order to introduce the PLL terminology and analysis, and then it discusses the theory and implementation of more complex PLL configurations such as zero‐crossing digital, sampling, and charge‐pump PLLs. Because the key PLL building block is the phase detector, its variants are also analyzed. Finally, the various PLL applications are surveyed.
Electromagnetic Materials
Authors: Choudhury Pankaj K. 
Published: December 2024

Abstract
This article describes the electromagnetic properties of certain types of mediums or materials in which the process of electromagnetics takes place. The introductory part discusses the evolution of electromagnetics based on theories and experiments by the pioneering scientists in the past. The following portions of the article deal with the different types of mediums, including isotropic and anisotropic dielectrics, conductors, semiconductors, superconductors, electrooptic, and optically active mediums. The fundamentals of magnetic materials are described in greater detail, explaining the mechanisms of magnetization and special materials such as ferrites. Bianisotropic materials and their constitutive equations are also discussed. Here, the focus is on some of the fundamental aspects of the constitutive characterization of bianisotropic mediums. The last three sections describe the basics and important applications of the phenomena of magnetostriction, piezoelectricity, and metamaterials.
Coulomb Gauge in Electromagnetics
Authors: Nevels Robert D. , Michalski Krzysztof A. 
Published: December 2024

Abstract
Problems in high frequency electromagnetic scattering and diffraction, where the fields are expressed in terms of magnetic vector and scalar potentials, have in the past almost exclusively been solved with the Lorenz gauge. However, in this chapter it will be shown that any wave guidance or scattering problem that can be found through an application of the Lorenz gauge can as well be solved subject to the Coulomb gauge. It will be shown that the Coulomb gauge formulation displays some unique mathematical characteristics that provide insight into the meaning and structure of potentials. Also, the component parts of the mathematical expressions for the field arising from an application of the Coulomb gauge provide a way of directly determining how the field changes with a change in frequency.