bluuebunny/crossref_metadata_2025 huggingface dataset:
Linear hash functions
Authors: Alon Noga , Dietzfelbinger Martin , Miltersen Peter Bro , Petrank Erez , Tardos Gábor
Published: July 2002

Consider the set ℋ of all linear (or affine) transformations between two vector spaces over a finite field
F
. We study how good ℋ is as a class of hash functions, namely we consider hashing a set
S
of size
n
into a range having the same cardinality
n
by a randomly chosen function from ℋ and look at the expected size of the largest hash bucket. ℋ is a universal class of hash functions for any finite field, but with respect to our measure different fields behave differently.

If the finite field
F
has
n
elements, then there is a bad set
S
⊂
F
2
of size
n
with expected maximal bucket size Ω(
n
1/3
). If
n
is a perfect square, then there is even a bad set with largest bucket size
always
at least √n. (This is worst possible, since with respect to a universal class of hash functions every set of size
n
has expected largest bucket size below √ + 1/2.)

If, however, we consider the field of two elements, then we get much better bounds. The best previously known upper bound on the expected size of the largest bucket for this class was
O
(2
√ log n
). We reduce this upper bound to
O
(log
n
log log
n
). Note that this is not far from the guarantee for a random function. There, the average largest bucket would be Θ (log
n
/ log log
n
).

In the course of our proof we develop a tool which may be of independent interest. Suppose we have a subset
S
of a vector space
D
over
Z
2
, and consider a random linear mapping of
D
to a smaller vector space
R
. If the cardinality of
S
is larger than
c
ε
|
R
|log|
R
|, then with probability 1 - ϵ, the image of
S
will cover all elements in the range.
A numbering system for combinations
Authors: Knott Gary D.
Published: July 2002

It is often necessary to generate the sequence of combinations of
s
things chosen from among
n
things, or to generate a random member of this sequence. Various algorithms have been given for these tasks. Algorithm 94 [1] is a good combination generator, and methods for generating a random combination are discussed in [2, pp. 121-125].
On compiling algorithms for arithmetic expressions
Authors: Nakata Ikuo
Published: July 2002

This paper deals with algorithms concerning arithmetic expressions used in a FORTRAN IV compiler for a HITAC-5020 computer having
n
accumulators. The algorithms generate an object code which minimizes the frequency of storing and recovering the partial results of the arithmetic expressions in cases where there are several accumulators.
Using temporal hierarchies to efficiently maintain large temporal databases
Authors: Dean Thomas
Published: July 2002

Many real-world applications involve the management of large amounts of time-dependent information. Temporal database systems maintain this information in order to support various sorts of inference (e.g., answering questions involving propositions that are true over some intervals and false over others). For any given proposition, there are typically many different occasions on which that proposition becomes true and persists for some length of time. In this paper, these occasions are referred to as time tokens. Many routine database operations must search through the database for time tokens satisfying certain temporal constraints. To expedite these operations, this paper describes a set of techniques for organizing temporal information by exploiting the local and global structure inherent in a wide class of temporal reasoning problems. The global structure of time is exemplified in conventions for partitioning time according to the calendar and the clock. This global structure is used to partition the set of time tokens to facilitate retrieval. The local structure of time is exemplified in the causal relationships between events and the dependencies between planned activities. This local structure is used as part of a strategy for reducing the computation required during constraint propagation. The organizational techniques described in this paper are quite general, and have been used to support a variety of powerful inference mechanisms. Integrating these techniques into an existing temporal database system has increased, by an order of magnitude or more in most applications, the number of time tokens that can be efficiently handled. —
Author's Abstract
PARASITES AND PATHOGENS OF MITES
Authors: Poinar G. , Poinar R.
Published: July 2002

▪ Abstract  Mites are an ancient group of arachnids that have had some 400 million years to adapt to a variety of conditions on Earth. Microorganisms have had the same amount of time to form symbiotic relationships with mites, with results ranging from phoresy to parasitism. This review covers the still fragmentary information on the groups of parasites and pathogens that are associated with mites. The known mite-associated bacteria, rickettsiae, fungi, Protozoa, viruses, and nematodes represent the tip of the iceberg, and few details of their host-parasite relationships have been recorded. Mites offer an opportunity to investigate new pathogens and new types of associations. Pathogens can be a boon when they affect mites that are detrimental to crops, livestock, or ourselves, and the diseases they cause probably play an important role in controlling mites, at least under certain conditions. However, pathogens can also cause crop failure and economic loss when they occur in biological control agents of pests.
DIET, NUTRITION, AND PROSTATE CANCER
Authors: Clinton Steven K. , Giovannucci Edward
Published: July 2002

▪ Abstract  Cancer of the prostate gland is one of the most common malignancies in affluent nations, in part due to the application of new screening and diagnostic tools. The development of life-threatening prostate cancer is the culmination of a complex series of initiation and promotional events over a period of decades and under the influence of many interacting genetic and environmental factors. A rapidly accumulating scientific literature provides compelling evidence for the hypothesis that diet and nutrition are important factors modifying risk of prostate cancer. Additional resources devoted to interactive research efforts by laboratory scientists and epidemiologists will provide further enlightenment and continued refinement of our assessment of risks and benefits for specific nutrients and dietary patterns. These studies provide hope that evidence-based dietary interventions will significantly impact the risk of prostate cancer and enhance the efficacy of therapeutic interventions.
ENVIRONMENTAL RISK FACTORS AND FEMALE BREAST CANCER
Authors: Laden Francine , Hunter David J.
Published: July 2002

▪ Abstract  The increasing incidence of breast cancer in the United States and the international variation in risk have led to speculation that environmental risk factors are an important cause of breast cancer. We review the epidemiologic evidence on the breast cancer risk associated with ambient environmental exposures experienced passively by the US population, and discuss the difficulties associated with measurement of specific exposures in environmental studies. We review geographic variation of breast cancer rates in the United States, and exposure to organochlorines, ionizing and electromagnetic radiation, and passive smoking. Results are inconclusive but do not support a major role of environmental risk factors in the etiology of breast cancer.
Differential Impact of the FMR-1 Full Mutation on Memory and Attention Functioning: A Neuropsychological Perspective
Authors: Cornish Kim M. , Munir Fehmidah , Cross Gareth
Published: July 2002

Memory and attention processing were examined in a group of 15 adult Fragile-X syndrome (FXS) males with Fragile-X mental retardation 1 (FMR-1) full mutation and compared to two control groups: a learning disabled (LD) control and a normal functioning control. Performance was assessed across a wide range of tasks including working memory, recognition memory, selective attention, sustained attention, and attentional switching. All three groups performed at a comparable level on recognition memory tasks, and the Fragile-X males and LD control group performed worse than the control group on tasks of working memory and sustained attention. On a task of executive function, the Fragile-X males demonstrated a significant deficit in comparison to the LD control group and the normal control group, but performed better than the LD control group and at a comparable level to the control group on tasks of selective attention. Molecular analyses of the lymphocyte DNA provided little evidence for a correlation between expansion size and performance on tasks of memory and attention. The findings from the present study are discussed in the context of functional neuroimaging and brain-behavior-molecular correlates.
Learning Hough Transform: A Neural Network Model
Authors: Basak Jayanta
Published: July 2002

A single-layered Hough transform network is proposed that accepts image coordinates of each object pixel as input and produces a set of outputs that indicate the belongingness of the pixel to a particular structure (e.g., a straight line). The network is able to learn adaptively the parametric forms of the linear segments present in the image. It is designed for learning and identification not only of linear segments in two-dimensional images but also the planes and hyperplanes in the higher-dimensional spaces. It provides an efficient representation of visual information embedded in the connection weights. The network not only reduces the large space requirement, as in the case of classical Hough transform, but also represents the parameters with high precision.
No Free Lunch for Early Stopping
Authors: Cataltepe Zehra , Abu-Mostafa Yaser S. , Magdon-Ismail Malik
Published: July 2002

We show that with a uniform prior on models having the same training error, early stopping at some fixed training error above the training error minimum results in an increase in the expected generalization error.
Magmatic and metasomatic processes during formation of the Nb-Zr-REE deposits Khaldzan Buregte and Tsakhir (Mongolian Altai): Indications from a combined CL-SEM Study
Authors: Kempe U. , Götze J. , Dandar S. , Habermann D.
Published: July 2002

Cathodoluminescence (CL) imaging and spectroscopy, as well as backscattered electron imaging, were used to assign the occurrence of several mineral phases and rock structures in altered nordmarkites and calcite-bearing granites from the Nb-Zr-REE deposits from Khaldzan Buregte and Tsakhir (Mongolian Altai) to three events: (1) intrusion of barren nordmarkites; (2) intrusion of small bodies of calcite-bearing granites with metasomatic alteration of the wall-rocks; and (3) alteration by F-rich fluids.

Unusual red and yellow CL caused by Fe3+ and Mn2+ emission centres were detected in microcline and albite. Fe3+ centres were also established (along with others) in quartz, zircon, and possibly in fluorite.

Magmatic and metasomatic rock structures and internal structures of the minerals coexist in the samples. The primary magmatic features were in part preserved during alteration. In contrast, the internal and the centre structures may be changed during alteration even in non-replaced mineral phases. Euhedral minerals may be formed by secondary processes as shown for lath-shaped albite. The occurrence of pseudomorphs, the inheritance of elements during replacement, and the mechanical effects of secondary minerals on earlier mineral phases during metasomatic growth are proposed as criteria for the reconstruction of the mineral succession in altered rocks. Snowball structures may be formed as a result of metasomatic alteration rather than as a magmatic intergrowth.
Increases in circulating and lymphoid tissue interleukin-10 in autoimmune lymphoproliferative syndrome are associated with disease expression
Authors: Lopatin Uri , Yao Xu , Williams Richard K. , Bleesing Jack J. H. , Dale Janet K. , Wong David , Teruya-Feldstein Julie , Fritz Scott , Morrow Matthew R. , Fuss Ivan , Sneller Michael C. , Raffeld Mark , Fleisher Thomas A. , Puck Jennifer M. , Strober Warren , Jaffe Elaine S. , Straus Stephen E.
Published: July 2002

Autoimmune lymphoproliferative syndrome (ALPS) is an inherited disorder in which genetic defects in proteins that mediate lymphocyte apoptosis, most often Fas, are associated with enlargement of lymph nodes and the spleen and a variety of autoimmune manifestations. Some patients with ALPS have relatives with these same apoptotic defects, however, who are clinically well. This study showed that the circulating levels of interleukin 10 (IL-10) were significantly higher (P < .001) in 21 patients with ALPS than in healthy controls. Moreover, the peripheral blood mononuclear cells (PBMCs) and lymphoid tissues of these patients with ALPS contained significantly higher levels of IL-10 messenger RNA (mRNA;P < .001 and P < .01, respectively). By fractionating PBMC populations, disproportionately high concentrations of IL-10 mRNA were found in the CD4−CD8−T-cell population, expansion of which is virtually pathognomonic for ALPS. Immunohistochemical staining showed intense IL-10 protein signals in lymph node regions known to contain CD4−CD8− T cells. Nonetheless, in vitro studies showed no influence of IL-10 on the survival of CD4−CD8− T cells. Overexpression of IL-10 in patients with inherited apoptotic defects is strongly associated with the overt manifestations of ALPS.
Altered T-cell receptor + CD28-mediated signaling and blocked cell cycle progression in interleukin 10 and transforming growth factor-β–treated alloreactive T cells that do not induce graft-versus-host disease
Authors: Boussiotis Vassiliki A. , Chen Zong-Ming , Zeller Jay C. , Murphy William J. , Berezovskaya Alla , Narula Satwant , Roncarolo Maria G. , Blazar Bruce R.
Published: July 2002

The induction of anergy in T cells, although widely accepted as critical for the maintenance of tolerance, is still poorly understood at the molecular level. Recent evidence demonstrates that in addition to blockade of costimulation using monoclonal antibodies (mAbs) directed against cell surface determinants, treatment of mixed lymphocyte reaction (MLR) cultures with interleukin 10 (IL-10) and transforming growth factor-β (TGF-β) results in induction of tolerance, rendering alloreactive murine CD4+ T cells incapable of inducing graft-versus-host disease (GVHD) after in vivo transfer to histoincompatible recipients. The present study, using these cells prior to adoptive transfer, determined that IL-10 + TGF-β–tolerant CD4+ T cells exhibit an altered pattern of T-cell receptor (TCR) + CD28-mediated signaling and are incapable of progressing out of the G1 phase of the cell cycle during stimulation with HLA class II disparate antigen-presenting cells. TGFβ + IL-10–tolerant cells were incapable of phosphorylating TCR-ζ, or activating ZAP-70, Ras, and MAPK, similarly to T-cell tolerized by blockade of B7/CD28 and CD40/CD40L pathways. Moreover, these cells were incapable of clonal expansion due to defective synthesis of cyclin D3 and cyclin A, and defective activation of cyclin-dependent kinase (cdk)4, cdk6, and cdk2. These cells also exhibited defective down-regulation of p27kip1 cdk inhibitor and lack of cyclin D2-cdk4 activation, Rb hyperphosphorylation, and progression to the S phase of the cell cycle. These data link anergy-specific proximal biochemical alterations and the downstream nuclear pathways that control T-cell expansion and provide a biochemical profile of IL-10 + TGF-β–tolerant alloreactive T cells that do not induce GVHD when transferred into MHC class II disparate recipients in vivo.
Caspase 8 activation independent of Fas (CD95/APO-1) signaling may mediate killing of B-chronic lymphocytic leukemia cells by cytotoxic drugs or γ radiation
Authors: Jones Dylan T. , Ganeshaguru Kanagasabai , Virchis Andres E. , Folarin Najeem I. , Lowdell Mark W. , Mehta Atul B. , Prentice H. Grant , Hoffbrand A. Victor , Wickremasinghe R. Gitendra
Published: July 2002

Ligation of the cell-surface Fas molecule by its ligand (Fas-L) or agonistic anti-Fas monoclonal antibodies results in the cleavage and activation of the cysteine protease procaspase 8 followed by the activation of procaspase 3 and by apoptosis. In some leukemia cell lines, cytotoxic drugs induce expression of Fas-L, which may contribute to cell killing through the ligation of Fas. The involvement of Fas, Fas-L, and caspase 8 was studied in the killing of B-cell chronic lymphocytic leukemia (B-CLL) cells by chlorambucil, fludarabine, or γ radiation. Spontaneous apoptosis was observed at 24-hour incubation, with additional apoptosis induced by each of the cytotoxic treatments. Although Fas mRNA expression was elevated after exposure to chlorambucil, fludarabine, or γ radiation, Fas protein levels only increased after irradiation. Therefore, Fas expression may be regulated by multiple mechanisms that allow the translation of Fas mRNA only in response to restricted cytotoxic stimuli. None of the cytotoxic stimuli studied here induced Fas-L expression. An agonistic anti-Fas monoclonal antibody (CH-11) did not significantly augment apoptosis induction by any of the death stimuli. A Fas-blocking antibody (ZB4) did not inhibit spontaneous, chlorambucil-, fludarabine-, or radiation-induced apoptosis. However, procaspase 8 processing was induced by all cytotoxic stimuli. These data suggest that the Fas/Fas-L signaling system does not play a major role in the induction of apoptosis in B-CLL cells treated with cytotoxic drugs or radiation. However, Fas-independent activation of caspase 8 may play a crucial role in the regulation of apoptosis in these cells.
Experience of Older Adults and Their Family Members in the Kidney Transplant Evaluation
Authors: Butler Catherine R. , Gaughran Olivia A. , Taylor Janelle S. , Gee Patrick O. , O’Hare Ann M.
Published: December 2024

Importance

Transplant can be a valuable treatment option for older adults with kidney failure, and recent initiatives encourage more frequent referral to transplant centers. However, the evaluation process can be challenging, and most older adults do not ultimately receive a kidney.

Objective

To elucidate the perspectives and experiences of older adults with advanced kidney disease and their family members regarding the kidney transplant evaluation process.

Design, Setting, and Participants

This qualitative study, conducted between December 19, 2022, and February 5, 2024, included adults aged 65 years or older with advanced kidney disease (estimated glomerular filtration rate ≤20 mL/min/1.73 m2, receiving dialysis, or with a functioning kidney transplant) and their family members in Seattle, Washington.

Main Outcomes and Measures

Perspectives and experiences of patients and family members, identified through inductive thematic analysis of semi-structured interviews.

Results

A total of 26 older adults (16 [61.5%] men; median age, 68 years [range, 65-74 years]) with advanced kidney disease and 7 of their family members (4 [57.1%] women; median age, 65 years [range, 36-75 years]) were interviewed. Three dominant themes pertaining to the kidney transplant evaluation process were identified: (1) committed to transplant, (2) a complex and protracted process, and (3) responsibility without power. Because receiving a kidney was such an important priority, most participants were willing to engage in what could be a demanding process of testing and treatment narrowly focused on this future goal. However, the transplant evaluation could be lengthy, demanding, opaque, and fragmented, and patients often put other aspects of their lives on hold while awaiting an uncertain result. Patients and families often felt personally responsible for navigating and completing the transplant evaluation despite having little power to shape this process. Feeling responsible for the continued progress of a high-stakes evaluation process while remaining dependent on clinical teams and family members for support could strain relationships.

Conclusions and Relevance

This qualitative study found that older adults with advanced kidney disease and their family members were highly motivated to receive a kidney transplant but engagement in an evaluation process, over which they had little control, could have far-reaching implications for patients and families. These findings underline the importance of making the transplant evaluation process more transparent and person centered and of helping patients and families who are contemplating or engaged in the process to understand what to expect.
Adaptive Antenna Arrays
Authors: Sun Chen , Karmakar Nemai C. , Zomorodi Mohammad , Nguyen Dong H.
Published: December 2024

Adaptive array antennas play an important role in wireless communications systems. The article begins with a brief introduction to the evolution of wireless communications systems and demands for adaptive array antennas. After that, the current and future applications of adaptive array antennas in wireless communications systems are described. Next, the structures and implementations of the adaptive array antenna systems, including switched‐beam antennas, phased‐array antennas, digital beamforming (DBF) array antennas, parasitic array antennas, diversity antennas, and multiple input multiple output (MIMO), are discussed. The article concludes with a comparison of different adaptive array antenna architectures.
Radiation Patterns
Authors: Chryssomallis Michael , Christodoulou Christos
Published: December 2024

The radiation pattern of an antenna is one of its basic properties since it shows the way the antenna distributes its energy in space. It generally consists of a number of lobes, and if it is measured far away from the antenna, it is independent of distance. It is a function of angles and can be expressed as field or power pattern. It usually can be completely specified from the patterns in two planes, perpendicular to each other, the
E
‐ and
H
‐plane, respectively. Related to the radiation pattern of an antenna, a number of important parameters exist, such as radiation power density, beamwidth, radiation and beam efficiency, directivity, gain, and antenna polarization.

The subject of this article is to provide an introduction to radiation patterns and all the related important parameters. The content is organized in four sections. The first section introduces several antenna patterns, giving the necessary definitions and presenting the common types. The field regions of an antenna are also pointed out. In the second section, after the introduction of Poynting vector and radiation power density, radiation performance measures such as the beam solid angle, directivity, and gain of an antenna are defined. In the third section, the concepts of wave and antenna polarization are discussed. Finally, in the fourth section, a general case of antenna pattern calculation is considered, and numerical solutions are suggested for radiation patterns that are not available in simple closed‐form expressions.
Chirality
Authors: Lakhtakia Akhlesh
Published: December 2024

Chiral media have the ability to discriminate between left‐ and right‐handed electromagnetic fields. These media can be classified into two types: (1) isotropic chiral media and (2) structurally chiral media. The molecules of a naturally occurring isotropic chiral medium are handed, while an artificial chiral medium can be made by randomly dispersing electrically small, handed inclusions (such as springs) in an isotropic achiral host medium. The molecules or inclusions in a structurally chiral medium, such as a chiral nematic liquid crystal, are randomly positioned but have helicoidal orientational order. Structurally chiral media can also be artificially fabricated either as stacks of uniaxial laminae or using thin‐film technology. Formulations for electromagnetic fields in both classes of chiral media are succinctly presented here.
Frequency Independent Antennas
Authors: Cencich Thomas P. , Samson Timothy
Published: December 2024

Frequency‐independent (FI) antennas are radiating structures capable of maintaining consistent impedance and pattern characteristics over multiple‐decade bandwidths. Their finite size limits the lowest frequency of operation, and the finite precision of the center region bounds the highest frequency of operation. The geometry of an FI antenna must be specified by angles alone, and principles such as truncation and self‐complementarity are necessary and desired, respectively. In this chapter, Rumsey's theory of FI antennas, developed in the mid‐1950s, is thoroughly discussed, and historical highlights listing the most important contributions in this area are given. A mathematical derivation for a general FI structure is provided, and some special cases are considered both theoretically and practically. A description and an explanation of the underlying theory of operation for several FI antenna types, including equiangular spirals, conventional and unconventional sinuous antennas, and log‐periodic folded slot arrays, are also provided. A view of frequency independence through the modal content and contamination of the radiated far field is emphasized. Considerations for flush/conformal mounting are briefly discussed, including the use of log‐periodic lossless cavities and broadband conical cavities. Several examples of FI antenna hardware are shown.
Lens Antennas
Authors: Malherbe Johannes A. G.
Published: December 2024

Lenses can be employed to act as high‐gain scannable antennas. The optical principles that apply to lens antennas are discussed, as well as the materials used in the construction of lenses. The basic lens function is discussed, and examples given of simple planoconvex and planoconcave lenses, together with the equations that describe the lens surfaces. In order to reduce the lens size, lenses are zoned, and equations for lens zoning are given. Other lens parameters such as gain, sidelobe level, reflections, loss, and bandwidth are treated. Lens systems for scannable or multibeam antennas are described, and design and analysis procedures for Rotman lenses given. Other lenses discussed include Luneburg,
R
‐2
R
, integrated dielectric, and Fresnel zone lenses. Physical construction methods for Rotman, Luneburg, and Fresnel zone plate lenses are discussed. This includes three‐dimensional (3D) printing and use of metamaterials.
Yagi–Uda Antenna
Authors: Kaneda Noriaki , Deal William R.
Published: December 2024

The Yagi–Uda antenna is one of the most practical and commonly used antennas. It features high gain, low weight and profile, and is inexpensive to manufacture. In this article, the fundamental operation of the Yagi–Uda, as well as a classic graphical technique for obtaining a fixed gain design, is discussed. Several modern versions of the Yagi–Uda antenna are also described, which permit the antenna to be operated at microwave frequencies and allow for simple integration into planar arrays in various applications including modern wireless communications.
Finite‐Difference Time‐Domain Analysis Advances
Authors: Yu Wenhua , Zhang Xin
Published: December 2024

The finite‐difference time‐domain (FDTD) method is one of key numerical techniques to solve Maxwell's equations, which has the broad applications for a variety of electromagnetic problems such as electromagnetic propagation, electromagnetic compatibility (EMC), and electromagnetic interference (EMI). This article first reviews the basic FDTD techniques such as update equations, numerical dispersion, stability properties, boundary conditions and conformal techniques, and then focuses on some enhanced FDTD techniques such as parallelization techniques and hardware acceleration techniques that can be greatly used to extend applications of the regular FDTD methods.
RF MOSFETs
Authors: Kumari Vandana , Gupta Mridula , Saxena Manoj
Published: December 2024

In this article, the RF performance of different MOSFET architectures such as Silicon‐On‐Insulator (SOI), Lightly Doped Drain (LDD) MOSFET, Graphene FET, and Negative Capacitance (NC) FET have been reported based on the previously reported work in the form of equivalent circuits. Using the data reported in the literature, the cutoff frequency and maximum frequency of oscillation have been summarized with varying channel lengths. Compared results show that multigate architecture results in higher cutoff frequency and a maximum frequency of oscillation, which can be further increased by decreasing the channel length of the MOSFET architecture. However, the deterioration in the resulting device gain at lower channel length has also been reported. Furthermore, the performance of SOI, Silicon‐on‐Nothing (SON), Double Gate (DG), Double‐Gate Silicon‐On‐Insulator (DGSOI), and Empty Space in Double‐Gate (ESDG) architectures have been explored using ATLAS TCAD software tool for RF and digital parameters investigation. The various parameters explored in this article are current density, electric field, breakdown voltage, impact ionization rate, scattering parameters, noise conductance, minimum noise figure, and cross‐correlation factor. The presented results show that, for the same drain current value, ESDG architecture has higher device gain compared to other devices used for comparison along with higher cutoff frequency. However, this higher device gain comes at the cost of a slightly higher minimum noise figure but with improved noise conductance and cross‐correlation factor (slightly higher than DG). Thus, ESDG is a reliable candidate for LNA design compared to other devices.
Stability of Nonlinear Systems
Authors: Chen Guanrong
Published: December 2024

This chapter briefly presents the notion of stability of nonlinear systems in both continuous‐time and discrete‐time settings. Basic concepts and fundamental theorems of various system stabilities are introduced. These mainly include the important Lyapunov stability theory, along with some others particularly the orbital stability and the structural stability. The bounded‐input bounded‐output stability of maps is also discussed.
Antenna Testing and Measurements
Authors: Kefauver W. Neill , Samson Timothy
Published: December 2024

Antenna measurements have a wide range of end uses; in many cases, the need is to verify as‐built performance against the evermore sophisticated design tools. These electromagnetic design tools now include details on surface roughness and dielectric loading with computational speeds that make these problem easily completed on engineering workstation that would have required supercomputers a decade ago. In addition, the resulting simulations can be tied from RF (radio frequency) fields into detailed physics associated with power handling due to heat, corona breakdown, saturation, and multipaction. Properly verifying the performance has hence become more complex as the margins continue to be reduced on as‐built designs, and the antennas have more embedded electronics.

Antenna measurements have thus become more detailed with the increasing complexity of antennas. In the 1950s, the phase or quadrature response of the antenna was not required for many systems, only power detection was necessary. As the systems started to use techniques of phase and frequency modulation, the measurement of phase became more essential to characterizing system performance and improving polarization data also. Next, the need for knowledge extended to frequency and eventually time domain as increasingly the antenna became another electronic component in the microwave designers' tool kit. In the 2000s, the antenna has evolved into a shaped multibeam, polarization, and frequency agile device, not just for the military but for communications systems as well. In application, the next generation, from the 2020s onward, will see the concept of an antenna become blurred as the digital realm begins to reach down into the final layers of RF devices to the antenna itself.

Not all antenna testing is providing measurements of fields, but for this article, the author will not investigate testing that is not unique to antennas, such as temperature, vibration, shock, humidity, stress, wind, and other possibilities. Unless the RF properties are part of the performance evaluated during these other types of tests, the testing methods would be the same as for any black box taken to an environmental test facility.
Radar Target Recognition
Authors: Eom Kie B.
Published: December 2024

Recent advances in radar target recognition are presented. Modern radar systems provide information not available in other sensors with sufficient details for target recognition. Target recognition approaches using different types of radar systems are presented, and recent advances in target recognition approaches are discussed. Approaches to improve the performance of target detection by the fusion of information from different types of radars are presented. The reduction of speckle noise in radar images is important as imaging radar is inherently noisy. Recent advances in speckle noise reduction approaches are also presented.
Safety of RF Energy to Humans
Authors: Foster Kenneth R.
Published: December 2024

This article reviews considerations related to exposure assessment and biological effects of radiofrequency energy with emphasis on health and safety. The rationale for two major exposure limits is described. Major areas of controversy about health effects of low‐level radiofrequency energy are described, both as related to uncertainties in the scientific data and in large variations in exposure limits around the world.
Radio Astronomy
Authors: Davidson David B.
Published: December 2024

This chapter addresses radio astronomy. Following a brief history by way of introduction, the historical impact of radio astronomy on astrophysics is discussed, as is its contemporary role in multi‐wavelength astronomy. Major contemporary science cases motivating the development of future radio telescopes are outlined. Sensitivity and resolution are introduced as two of the most fundamental metrics of a radio telescope, and the improvement over time of these metrics is documented. Thereafter, design considerations for radio telescopes are discussed. These include single‐dish systems and interferometric synthesis arrays. Design issues for both dish and aperture arrays are considered. The basic principles of interferometry and aperture synthesis are outlined, as well as very long baseline interferometry. New technologies impacting on current designs are highlighted, including phased array feeds, very low noise amplifiers, and electromagnetic simulation methods. Radio frequency interference is briefly considered. The chapter concludes with a look to the future of radio astronomy, in particular the Square Kilometer Array; construction of this international project was starting as this book was going to press.
Reconfigurable Evanescent Cavity Mode Filters
Authors: Khater Mohammad Abu , Peroulis Dimitrios
Published: December 2024

Evanescent‐mode resonators offer a plethora of advantages including high tuning range, quality factor, linearity, and power handling in a mobile form factor. This chapter presents the basic resonator design concept along with advanced tunable RF filters with excellent performance. The versatility of the available couplings also makes evanescent‐mode resonators ideal for many others circuits and systems beyond filters. This article also discusses a number of such circuits that cover a wide frequency range (100 GHz) and high power levels (about 90 W). We review circuits commonly found in receivers (LNAs), transmitters (PAs), and lab‐scale testing (e.g., synthesizers). Evanescent‐mode‐based circuits and systems can be implemented with commercially available low‐cost technologies such as PCB, microfabrication, and injection molding. These features make the presented technology attractive to a wide variety of applications.
MicroRNAs in seminal plasma are able to discern infertile men at increased risk of developing testicular cancer
Authors: Ferrara Carmen , Battaglia Rosalia , Caponnetto Angela , Fazzio Anna , Stella Michele , Barbagallo Cristina , Musso Nicolò , Lunelio Federica , Vento Maria Elena , Borzì Placido , Scollo Paolo , Barbagallo Davide , Ragusa Marco , Pernagallo Salvatore , Di Pietro Cinzia
Published: December 2024

Male infertility is a risk factor for the development of testicular germ cell tumors. In this study, we investigated microRNA profiles in seminal plasma to identify potential noninvasive biomarkers able to discriminate the men at highest risk of developing cancer among the infertile population. We compared the microRNA profiles of individuals affected by testicular germ cell tumors and healthy individuals with normal or impaired spermiograms using high‐throughput technology and confirmed the results by single‐assay digital PCR. We found that miR‐221‐3p and miR‐222‐3p were downregulated and miR‐126‐3p was upregulated in cancer patients compared to both infertile and fertile men. ROC curve analysis confirmed that miR‐126 upregulation is able to identify cancer patients among the infertile male population. In addition, in‐depth bioinformatics analysis based on weighted gene co‐expression networks showed that the identified miRNAs regulate cellular pathways involved in cancer.
19.5%‐Efficiency Organic Solar Cells with High Thickness Tolerance and Exceptional Device Stability Enabled by TEMPO‐Functionalized Perylene Diimide as a Cathode Interface Layer
Authors: Guo Yawen , Ma Xueqing , Song Haoming , Chen Jieni , Zhang Wenkai , Xu Xinjun , Li Cuihong , Liu Yuqiang , Liu Yahui , Bo Zhishan
Published: December 2024

The cathode interface material is pivotal for achieving excellent photovoltaic performance and device stability in organic solar cells (OSCs). However, currently, few interface materials can simultaneously satisfy multiple criteria such as low cost, high efficiency, insensitivity to film thickness, and good stability. To address this challenge, a novel perylene diimide (PDI) derivative, P‐C3T is designed and synthesized, by incorporating stable free radical unit TEMPO and polar quaternary ammonium salt as side chains. P‐C3T is facile to synthesize and cost‐effective, while also exhibiting good conductivity and excellent ohmic contact characteristics in OSCs. When utilized as the cathode interface material, the device based on D18:L8‐BO achieves a remarkable power conversion efficiency (PCE) of 19.52%, which is one of the highest levels reported for binary single‐junction OSCs. Notably, devices based on P‐C3T exhibit remarkable insensitivity to film thickness, with the PCE remaining at 95% of the initial efficiency even at a thickness of 40 nm. Furthermore, P‐C3T‐based OSCs demonstrate exceptional storage stability and improved light stability. In summary, with its high PCE, excellent thickness insensitivity, and good stability, P‐C3T is anticipated to be a promising candidate material for large‐area roll‐to‐roll processing of OSCs.
A Halogen‐free and Universally Volatile Solid Additive Enables Binary Organic Solar Cells to Exceed 19% Efficiency
Authors: Han Chenyu , Cheng Bo , Guo Qing , Fu Zhen , Qiao Jiawei , Cheng Sixuan , Huo Yumiao , Xia Xinxin , Wang Hao , Fu Yuang , Guo Xia , Lu Xinhui , Hao Xiaotao , Li Yongfang , Zhang Maojie
Published: December 2024

Additive processing is widely employed for regulating physical morphology to improve the performance of organic solar cells (OSCs). However, the dosage of commonly used solvent additives is problematic to control, leading to poor reproducibility of devices. Thus, this work innovatively introduces a low‐cost and commercialized material, dibenzoylmethane (DBM), as a volatile solid additive in OSCs based on PM6:Y6. DBM is well mixed with polymer donor and non‐fullerene acceptor, simultaneously facilitating the ordered molecular orientation and stacking of both the donor and acceptor, which leads to an improved double‐fibril network, thereby prolonging exciton diffusion length and suppressing charge carrier recombination. Ultimately, a champion power conversion efficiency (PCE) of 18.7% is achieved for DBM‐processed devices, which is the highest value reported in PM6:Y6‐based binary OSCs, and also achieved excellent thermal stability (T80 > 200 h, 85 °C) and storage stability (T80 > 5000 h). Moreover, the effect of DBM also exhibits decent universality in diverse blend systems, such as PM6:BTP‐eC9, PTQ10:m‐TEH, D18:N3, and D18:L8‐BO, and an impressive PCE of 19.4% is achieved. These findings demonstrate that DBM, as a low‐cost, halogen‐free solid additive with excellent universality, is promising for effectively improving device performances in future OSC applications.
Recent Advances and Challenges in Perovskite‐Based Protonic Ceramic Electrolytes: Design Strategies and Fabrication Innovations
Authors: Nie Haoyu , Liu Zuoqing , Xiao Ming , Yang Guangming , Li Tao , Starostina Inna A. , Medvedev Dmitry A. , Wang Wei , Zhou Wei , Ran Ran
Published: December 2024

Protonic ceramic electrochemical cells (PCECs) have received extensive research attention as full solid‐state, electrochemical devices that can interconvert electrical and chemical energies via rapid proton conduction at reduced temperatures. Nonetheless, the practical application of PCECs still faces numerous challenges. In addition to the development of electrode materials, the protonic ceramic electrolytes (PCEs), which are crucial for the performance and stability of PCECs, encounter issues such as poor sinterability, low ionic conductivity, and inadequate thermochemical matching. To address these obstacles, the design and optimization of protonic ceramic electrolytes have recently become essential research focuses in the field of PCECs. To achieve effective customization of the elemental composition, crystal structure, defect structure, ionic conductivity, and chemical stability, many candidates for electrolyte materials with various compositions have been proposed. This review also covers state‐of‐the‐art developments in PCE fabrication technologies, including powder synthesis, thin‐film deposition, more controllable sintering processes and interface treatments for structural integrity and ionic conductivity. This review comprehensively summarizes the most recent design approaches and optimization strategies for perovskite‐based protonic ceramic electrolyte materials and is crucial for advancing the commercialization of PCECs.
Membrane Fusion Strategy Boosts Immune Homeostasis, Mobilizing Macrophages to Eliminate Bacteria and Accelerate Skin Regeneration in Infected Burn Wound
Authors: Wang Xingyou , Sun Xiaoqing , Zeng Yating , Liu Shuyao , Yi Qiangying , Wu Yao
Published: December 2024

Immunotherapy holds promise as an alternative to antibiotics in treating burn infections. However, the inadequacy of immune response or excessive inflammation both hinder effective bacterial clearance through immunotherapy, therefore necessitating a comprehensive approach that not only enhances immunotherapy against bacteria but also maintains immune homeostasis and promotes skin regeneration. Here, a membrane fusion‐driven combination immunotherapy is reported that mobilizes macrophages to address abovementioned limitations. The core–shell structured membrane fusion‐liposomes (MFL‐Gal‐Mal/Cur) can fuse their functional phospholipid shells with macrophages and bacteria, resulting in the remodeling of targets' surfaces with the galactose‐maltotriose (Gal‐Mal) moieties, and delivering their cores (curcumin‐loaded mesoporous polydopamine, MPDA/Cur) into targets. The embedded Gal‐Mal on membranes enhances macrophages' ability to phagocytize bacteria, as well as increases bacteria's sensitivity to immune cell‐mediated killing. The intracellular MPDA/Cur evade lysosomal degradation, exerting antibacterial effects while also enhancing macrophage lysosomal bactericidal activity through autophagy promotion. This immunotherapy enhances macrophages’ capacity to phagocytize (increase rate for S. aureus: 21%; E. coli: 29%) and eliminate intracellular bacteria (clearance rate for S. aureus: 98%; E. coli: 99%), without exacerbating inflammatory responses. The release of MFL‐Gal‐Mal/Cur from the polysaccharide composite hydrogel can alleviate pain and itching sensations in infected burns, while activating the regeneration of skin appendages.
Selective Electrochemical Amine‐to‐Nitrile Conversion on Nickel−Cobalt Hydrogen Phosphate Nanowires Coupled with Hydrogen Generation
Authors: Dong Yuan , Wei Enhui , Yang Xu , Gao Hongtao , Luo Xiliang , Yang Wenlong
Published: December 2024

Developing highly active electrocatalysts for the benzylamine oxidation reaction (BOR) is very imperative for organic compounds upgrading. Meanwhile, clarifying the underlying BOR mechanism is of remarkable significance but still confronts challenges. Herein, bimetallic nickel‐cobalt hydrogen phosphate nanowires (NiCo‐HPNWs) are put forward as a high‐performance anodic catalyst for selective BOR. Furthermore, NiCo‐HPNWs is used as a proof‐of‐concept model to understand the synergistic effects between Ni and Co atoms during the BOR process. It is found that NiCo‐HPNWs catalyst shows excellent electrocatalytic BOR performance, with a small onset potential of 0.265 V versus. Ag/AgCl and a high faradic efficiency (FE) of 93.0% for benzonitrile (BN) production at 0.40 V versus. Ag/AgCl. Also, the FEs for BN production can reach ≈80% at voltages from 1.50 to 1.65 V by coupling the BOR with the hydrogen evolution reaction in a two‐electrode electrolyzer. Potential‐dependent in situ Raman spectroscopy sheds light on the direct electro‐oxidation mechanism of benzylamine (BA) over the NiCo‐HPNWs catalyst. In combination with X‐ray photoelectron spectroscopy and density functional theory calculations, the charge transfer behavior between Ni and Co atoms is revealed, which endows NiCo‐HPNWs with a favorable charge distribution to promote BA adsorption and BN desorption on the catalyst surface, thereby leading to expedited reaction kinetics and enhanced electrochemical BOR activity.
Design Principles for High‐Capacity, Long‐Life Cation‐Disordered Rocksalt Cathodes
Authors: Liu Fanjun , He Jia , Chen Hao , Yang Wei , Yu Runze , Lun Zhengyan
Published: December 2024

Lithium‐excess cation disordered rocksalt (DRX) cathodes have gained wide attention because of their capability of delivering high energy densities solely relying on inexpensive and earth‐abundant transition metal (TM) species. To date, various strategies have been proposed for their intrinsic performance optimization, including designing high‐entropy compositions to suppress cation short‐range order (SRO), incorporating high Mn content to promote the in situ phase transformation to a partially‐disordered spinel phase (δ phase) or Cr doping to enhance the Li‐ion mobility; however, the compatibility of these strategies remains unexplored. In this study, the interplay among the three strategies is systematically investigated when applied concurrently via the design of a series of DRX cathode compounds. The findings demonstrate that compared to the other two strategies, DRX‐to‐δ phase transformation induced by high Mn content plays a more significant role in improving the electrochemical performance of DRX cathodes, which simultaneously elevates the capacity and cycle life. Cr or multi‐elemental doping will inevitably dilute the Mn concentration, limiting the performance enhancement. These insights ultimately contribute to the design of an optimal composition that combines high capacity and long cycle life.