We explore properties of the class of Bekolle-Bonami weights B.sub.infinity introduced by the authors in a previous work. Although Bekolle-Bonami weights are known to be ill-behaved because they do ...not satisfy a reverse Holder property, we prove that when restricting to a class of weights that are "nearly constant on top halves", one recovers some of the classical properties of Muckenhoupt weights. We also provide an application of this result to the study of the spectra of certain integral operators.
We study a version of the Lebesgue differentiation theorem in which the integral averages are replaced with medians over Busemann-Feller differentiation bases. Our main result gives several ...characterizations for the differentiation property in terms of the corresponding median maximal function. As an application, we study pointwise behaviour in Besov and Triebel-Lizorkin spaces, where functions are not necessarily locally integrable. Most of our results apply also for functions defined on metric measure spaces. KEY WORDS: Lebesgue differentiation theorem, differentiation bases, median maximal function
Display omitted
•This paper summarizes diverse perspectives from researchers on binder aging.•This paper explores binder aging’s chemical, morphological, and rheological aspects.•This paper urges ...better methods for understanding binder aging phenomenon.
Asphalt binders, an indispensable component in road infrastructure construction and maintenance, have been utilized for centuries in the roads. While binders have demonstrated durability and resilience to growing climatic and traffic stressors, concerns persist regarding their susceptibility to aging, a factor that can significantly affect the performance and longevity of asphalt pavements. To address these concerns, extensive research is ongoing to continuously improve our understanding of aging on asphalt binders, employing a multi-aspect characterization approach. In this review paper, we aim to offer a comprehensive and insightful summary of the diverse perspectives provided by researchers on the intricate effects of aging on asphalt binders. We study the chemical, morphological, and rheological aspects of asphalt binder aging, shedding light on the multifaceted changes that occur as these materials mature over time. This cutting-edge approach provides a deeper understanding of the complex processes that underlie asphalt binder aging, keeping the industry up-to-date with the latest findings and breakthroughs. The overarching goal of this review paper is to inspire and motivate asphalt binder researchers to adopt a more holistic approach to characterization, one that considers multiple aspects of the aging phenomenon. By doing so, we can better understand how asphalt binders evolve and degrade over time, ultimately leading to more effective and long-lasting pavements. Furthermore, this review paper highlights the limitations of current methods and technologies, emphasizing the necessity for advancements in the field of asphalt binder aging characterization.
Microplastics (MPs) have globally been detected in aquatic and marine environments, which has raised scientific interests and public health concerns during the past decade. MPs are those polymeric ...particles with at least one dimension <5 mm. MPs possess complex physicochemical properties that vary their mobility, bioavailability and toxicity toward organisms and interactions with their surrounding pollutants. Similar to nanomaterials and nanoparticles, accurate and reliable detection and measurement of MPs or nanoplastics and their characteristics are important to warrant a comprehensive understanding of their environmental and ecological impacts. This review elaborates the principles and applications of diverse analytical instruments or techniques for separation, characterization and quantification of MPs in the environment. The strength and weakness of different instrumental methods in separation, morphological, physical classification, chemical characterization and quantification for MPs are critically compared and analyzed. There is a demand for standardized experimental procedures and characterization analysis due to the complex transformation, cross-contamination and heterogeneous properties of MPs in size and chemical compositions. Moreover, this review highlights emerging and promising characterization techniques that may have been overlooked by research communities to study MPs. The future research efforts may need to develop and implement new analytical tools and combinations of hyphenated technologies to complement respective limitations of detection and yield reliable characterization information for MPs. The goal of this critical review is to facilitate the research of plastic particles and pollutants in the environment and understanding of their environmental and human health effects.
Display omitted
•Separation, characterization and identification approaches for microplastics are summarized.•Principles, applications, advantages and limitations of each approach are discussed.•AFM and hybrid AFM techniques are proposed as emerging characterization platforms.•Standard experimental procedures and reliable characterization methods are on demand.
The shell of Hermetia illucens L. contains considerable amounts of chitin, which has various biological activities. So far, few studies have focused on chitin of Hermetia illucens L. as a source of ...chitosan and oligosaccharides. There is great potential for utilizing Hermetia illucens L. chitin to produce chitosan films in biomaterials. We studied different extraction conditions for chitin and extracted it from black soldier fly (BSF) (Hermetia illucens L.). Three processing steps were adopted: (1) demineralization, (2) deproteinization, and (3) decolorization. The chemical components (moisture, ash, protein, fat, residual protein, and residual mineral contents) and physicochemical characteristics of the chitin and chitosan extracted under these three conditions were determined. In addition, Fourier transform infrared spectroscopy and X-ray diffraction were used to analyze the extracted chitin and commercial samples, and the results showed that demineralization–deproteinization–decolorization treatments could achieve the highest chitin yield (7.18 ± 0.11 %), chitosan yield (64.22 ± 0.79 %), and the best purity (residual protein 0.56 ± 0.01 % and residual ash 0.58 ± 0.04 %), making it the best treatment method. Using this method, the residues produced from farmed BSF can be recycled and used as a new source of chitin.
The goals of this review paper on deep learning (DL) in medical imaging and radiation therapy are to (a) summarize what has been achieved to date; (b) identify common and unique challenges, and ...strategies that researchers have taken to address these challenges; and (c) identify some of the promising avenues for the future both in terms of applications as well as technical innovations. We introduce the general principles of DL and convolutional neural networks, survey five major areas of application of DL in medical imaging and radiation therapy, identify common themes, discuss methods for dataset expansion, and conclude by summarizing lessons learned, remaining challenges, and future directions.
•Overview of characterization techniques for molecularly imprinted polymers.•Several techniques are supported by own results.•Conventional techniques are covered such as EM, particle size analyzers, ...LC-MS/MS.•Advanced characterization techniques include NMR, TGA, DSC.•Specific characterization techniques exist for MIP on surfaces and sensors.
Molecularly imprinted polymers (MIP) represent synthetic recognition elements capable of interacting with a target analyte to obtain selective binding and/or detection and/or removal thereof. Various characterization techniques have been explored and evaluated. A first group concerns morphological characterization methods such as electron microscopy (EM), particle size analysis and pore size determination. Secondly, techniques have evolved for analysis of chemical structure characteristics (nuclear magnetic resonance, infrared investigation) and thermal features (thermogravimetric analysis, differential scanning calorimetry). Additionally, selective target binding is mostly studied by liquid chromatography coupled to different detectors. Finally, MIP structures on surfaces such as immobilized particles and films are frequently investigated by EM, atomic force microscopy, static contact angle measurements, X-ray photoelectron spectroscopy, quartz crystal microbalance and surface plasmon resonance.
The current review provides an overview of the above mentioned MIP characterization techniques. In most cases, the techniques covered are illustrated with data obtained for MIP against ergot alkaloids.
PDF
