Frontiers in Physics最新文献

{"title":"Assessment of a method for manufacturing realistic breast lesions for experimental investigations","authors":"Kristina Bliznakova, Nikolay Dukov, Olina Toshkova-Velikova, Zhivko Bliznakov","doi":"10.3389/fphy.2024.1441740","DOIUrl":"https://doi.org/10.3389/fphy.2024.1441740","url":null,"abstract":"IntroductionThe development and optimization of novel diagnostic imaging prototypes heavily rely on experimental work. In radiology, this experimental work involves the use of phantoms. When testing novel techniques to demonstrate their advantages, anthropomorphic phantoms are utilized. The aim of this study was to investigate seven materials for 3D printing to replicate the radiological properties of breast lesions.MethodsTo achieve this objective, we utilized three fused filament fabrication materials, namely, polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and polyethylene terephthalate glycol (PET-G), along with resins such as White v4 Resin, Flexible 80A v1 Resin, Model v2 Resin, and Wax40 v1 Resin, to 3D print seven irregularly shaped lesions. These lesions were used to prepare a set of seven physical phantoms, each filled with either water or liquid paraffin, and one of the printed lesions. The phantoms were then scanned using a mammography unit at 28 kVp. Additionally, six computational breast phantoms, replicating the shape of the physical phantoms, were generated. These computational models were assigned the attenuating properties of various breast tissues, including glandular tissue, adipose tissue, skin, and lesions. Mammography images were generated under the same experimental conditions as the physical scans. Both the simulated and experimental images were evaluated for their contrast-to-noise ratio (CNR) and contrast (C).DiscussionThe results indicated that the studied resins and filament-based materials are all suitable for replicating breast lesions. Among these, PLA and White v4 Resin exhibited the densest formations and can effectively approximate breast lesions that are slightly less attenuating than glandular tissue, while ABS and Flexible 80A v1 Resin were the least dense and can represent fat-containing breast lesions. The remaining materials provided good approximations for malignant lesions. These materials can be utilized for constructing phantoms for experimental work, rendering the model a valuable tool for optimizing mammography protocols, ensuring quality control of mammography X-ray equipment, and aiding in the diagnosis and assessment of breast cancer.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"10 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observation of critical scaling in spin glasses below Tc using thermoremanent magnetization","authors":"G. G. Kenning, M. Brandt, R. Brake, M. Hepler, D. Tennant","doi":"10.3389/fphy.2024.1443298","DOIUrl":"https://doi.org/10.3389/fphy.2024.1443298","url":null,"abstract":"Time-dependent thermoremanent magnetization (TRM) studies have been instrumental in probing energy dynamics within the spin glass phase. In this paper, we review the evolution of the TRM experiment over the last half century and discuss some aspects related to how it has been used in the understanding of spin glasses. We also report on recent experiments using high-resolution DC SQUID magnetometry to probe the TRM at temperatures less than but near to the transition temperature <jats:italic>T</jats:italic><jats:sub><jats:italic>c</jats:italic></jats:sub>. These experiments have been performed as a function of waiting time, temperature, and five different magnetic fields. We find that as the transition temperature is approached from below, the characteristic time scale of TRM is suppressed up to several orders of magnitude in time. In the highest-temperature region, we find that the waiting time effect subsides, and a waiting time-independent crossover line is reached. We also find that increasing the magnetic field further suppresses the crossover line. Using a first-principles energy argument across the crossover line, we derive an equation that is an excellent fit to the crossover lines for all magnetic fields probed. The data show strong evidence for critical slowing down and an <jats:italic>H</jats:italic> = <jats:italic>0 Oe</jats:italic> phase transition.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"182 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling network motifs as higher order interactions: a statistical inference based approach","authors":"Anatol E. Wegner","doi":"10.3389/fphy.2024.1429731","DOIUrl":"https://doi.org/10.3389/fphy.2024.1429731","url":null,"abstract":"The prevalent approach to motif analysis seeks to describe the local connectivity structure of networks by identifying subgraph patterns that appear significantly more often in a network then expected under a null model that conserves certain features of the original network. In this article we advocate for an alternative approach based on statistical inference of generative models where nodes are connected not only by edges but also copies of higher order subgraphs. These models naturally lead to the consideration of latent states that correspond to decompositions of networks into higher order interactions in the form of subgraphs that can have the topology of any simply connected motif. Being based on principles of parsimony the method can infer concise sets of motifs from within thousands of candidates allowing for consistent detection of larger motifs. The inferential approach yields not only a set of statistically significant higher order motifs but also an explicit decomposition of the network into these motifs, which opens new possibilities for the systematic study of the topological and dynamical implications of higher order connectivity structures in networks. After briefly reviewing core concepts and methods, we provide example applications to empirical data sets and discuss how the inferential approach addresses current problems in motif analysis and explore how concepts and methods common to motif analysis translate to the inferential framework.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"3 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical clearing: an alternative sample preparation method for propagation based phase contrast μCT","authors":"Md Motiur Rahman Sagar, Angelika Svetlove, Lorenzo D’Amico, Diana Pinkert-Leetsch, Jeannine Missbach-Guentner, Elena Longo, Giuliana Tromba, Hanibal Bohnenberger, Frauke Alves, Christian Dullin","doi":"10.3389/fphy.2024.1433895","DOIUrl":"https://doi.org/10.3389/fphy.2024.1433895","url":null,"abstract":"Synchrotron radiation propagation-based phase-contrast micro-computed tomography (SR<jats:inline-formula><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mi mathvariant=\"normal\">μ</mml:mi></mml:math></jats:inline-formula>CT) has been used increasingly for detailed characterization of tissue specimens, alternative to classical histology. It allows rapid and non-destructive three-dimensional (3D) virtual histology of unstained specimens. Although many studies show that standard protocols for formalin-fixation and paraffin-embedded (FFPE) tissue specimens are well suited for propagation based phase-contrast imaging (PBI), refinement of sample preparation protocols for this relatively recent development is still in its early stage. There are several limitations using FFPE blocks including air-bubble inclusion, and crack formation, which affect the quality of the micro-CT scans. In this study we demonstrate that optical clearing of colon cancer specimen followed by embedding in Phytagel, as an alternative sample preparation protocol yields comparable PBI micro-CT image quality and mitigates the aforementioned drawbacks of FFPE specimens. Moreover, since single-distance phase retrieval algorithms for PBI image reconstruction expect scanned materials to be either weakly-absorbing or having a fixed ratio between absorption and phase shift, we hypothesize that optical clearing will result in specimens that are well in line with these mathematical assumption of the applied phase retrieval algorithm (homogeneous form of the Transport-of-Intensity equation TIE-HOM). In addition, we show that classical histological analysis is still possible after re-embedding of the specimen in paraffin. Thus, the proposed novel workflow to scan optical cleared specimens using SR<jats:inline-formula><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mi mathvariant=\"normal\">μ</mml:mi></mml:math></jats:inline-formula>CT can be used in combination with light sheet microscopy and can be integrated in a classical pipeline for pathological tissue characterization.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"37 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum-enhanced photoprotection in neuroprotein architectures emerges from collective light-matter interactions","authors":"Hamza Patwa, Nathan S. Babcock, Philip Kurian","doi":"10.3389/fphy.2024.1387271","DOIUrl":"https://doi.org/10.3389/fphy.2024.1387271","url":null,"abstract":"BackgroundSuperradiance is the phenomenon of many identical quantum systems absorbing and/or emitting photons collectively at a higher rate than any one system can individually. This phenomenon has been studied analytically in idealized distributions of electronic two-level systems (TLSs), each with a ground and excited state, as well as numerically in realistic photosynthetic nanotubes and cytoskeletal architectures.MethodsSuperradiant effects are studied here in idealized toy model systems and realistic biological mega-networks of tryptophan (Trp) molecules, which are strongly fluorescent amino acids found in many proteins. Each Trp molecule acts as a chromophore absorbing in the ultraviolet spectrum and can be treated approximately as a TLS, with its &lt;jats:inline-formula&gt;&lt;mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;mml:mn&gt;1&lt;/mml:mn&gt;&lt;mml:msub&gt;&lt;mml:mrow&gt;&lt;mml:mi&gt;L&lt;/mml:mi&gt;&lt;/mml:mrow&gt;&lt;mml:mrow&gt;&lt;mml:mi&gt;a&lt;/mml:mi&gt;&lt;/mml:mrow&gt;&lt;/mml:msub&gt;&lt;/mml:math&gt;&lt;/jats:inline-formula&gt; excited singlet state; thus, organized Trp networks can exhibit superradiance. Such networks are found, for example, in microtubules, actin filaments, and amyloid fibrils. Microtubules and actin filaments are spiral-cylindrical protein polymers that play significant biological roles as primary constituents of the eukaryotic cytoskeleton, while amyloid fibrils have been targeted in a variety of neurodegenerative diseases. We treat these proteinaceous Trp networks as open quantum systems, using a non-Hermitian Hamiltonian to describe interactions of the chromophore network with the electromagnetic field. We numerically diagonalize the Hamiltonian to obtain its complex eigenvalues, where the real part is the energy and the imaginary part is its associated enhancement rate. We also consider multiple realizations of increasing static disorder in either the site energies or the decay rates.ResultsWe obtained the energies and enhancement rates for realistic microtubules, actin filament bundles, and amyloid fibrils of differing lengths, and we use these values to calculate the quantum yield, which is the ratio of the number of photons emitted to the number of photons absorbed. We find that all three of these structures exhibit highly superradiant states near the low-energy portion of the spectrum, which enhances the magnitude and robustness of the quantum yield to static disorder and thermal noise.ConclusionThe high quantum yield and stable superradiant states in these biological architectures may play a photoprotective role &lt;jats:italic&gt;in vivo&lt;/jats:italic&gt;, downconverting energetic ultraviolet photons—absorbed from those emitted by reactive free radical species—to longer, safer wavelengths and thereby mitigating biochemical stress and photophysical damage. Contrary to conventional assumptions that quantum effects cannot survive in large biosystems at high temperatures, our results suggest that macropolymeric collectives of TLSs in microtubules, actin filaments, and amyloid fibr","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"3 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Josephson parametric amplifier based quantum noise limited amplifier development for axion search experiments in CAPP","authors":"Sergey V. Uchaikin, Jinmyeong Kim, Caǧlar Kutlu, Boris I. Ivanov, Jinsu Kim, Arjan F. van Loo, Yasunobu Nakamura, Saebyeok Ahn, Seonjeong Oh, Minsu Ko, Yannis K. Semertzidis","doi":"10.3389/fphy.2024.1437680","DOIUrl":"https://doi.org/10.3389/fphy.2024.1437680","url":null,"abstract":"This paper provides a comprehensive overview of the development of flux-driven Josephson Parametric Amplifiers (JPAs) as Quantum Noise Limited Amplifier for axion search experiments conducted at the Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science. It focuses on the characterization, and optimization of JPAs, which are crucial for achieving the highest sensitivity in axion particle detection. We discuss various characterization techniques, methods for improving bandwidth, and the attainment of ultra-low noise temperatures. JPAs have emerged as indispensable tools in CAPP’s axion search endeavors, playing a significant role in advancing our understanding of fundamental physics and unraveling the mysteries of the Universe.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"5 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variance and skewness of the multiplication gain distribution in uniform avalanche diodes","authors":"P. Zambon","doi":"10.3389/fphy.2024.1452279","DOIUrl":"https://doi.org/10.3389/fphy.2024.1452279","url":null,"abstract":"We derived exact analytical expressions for the variance, the third central moment, and the skewness of the multiplication gain distribution in uniform avalanche structures. The model assumes Poissonianity and locality of the ionization process and is valid for arbitrary values of the electron and hole ionization coefficients, <jats:inline-formula><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mi>α</mml:mi></mml:math></jats:inline-formula> and <jats:inline-formula><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mi>β</mml:mi></mml:math></jats:inline-formula>, respectively, as functions of the space coordinate. Expressions are also provided for the particular case where the ionization coefficients are related by a constant ratio <jats:inline-formula><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mi>k</mml:mi><mml:mo>=</mml:mo><mml:mi>β</mml:mi><mml:mo>/</mml:mo><mml:mi>α</mml:mi></mml:math></jats:inline-formula>. The skewness is found to be always positive and greater than 2, indicating statistically relevant. Finally, the implications for spectral measurements of ionizing radiation are reviewed.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"21 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FSE-RBFNN-based LPF-AILC of finite time complete tracking for a class of time-varying NPNL systems with initial state errors","authors":"Chunli Zhang, Lei Yan, Yangjie Gao, Junliang Yao, Fucai Qian","doi":"10.3389/fphy.2024.1442486","DOIUrl":"https://doi.org/10.3389/fphy.2024.1442486","url":null,"abstract":"The paper proposes a low-pass filter adaptive iterative learning control (LPF-AILC) strategy for unmatched, uncertain, time-varying, non-parameterized nonlinear systems (NPNL systems). To address the difficulty of nonlinear parameterization terms in system models, a new function approximator (FSE-RBFNN), which combines the radial basis function neural network (RBFNN) and Fourier series expansion (FSE), is introduced to model each time-varying nonlinear parameterized function. The adaptive backstepping method is used to design control laws and parameter adaptive laws. In the process of controller design, we may encounter the problem of too many derivatives, which can cause parameter explosions after derivatives. Therefore, we introduce a first-order low-pass filter to solve this problem and simplify the structure of the controller. As the number of iterations increases, the maximum tracking error gradually decreases until it converges to the nearby region, approaching zero within the entire given interval <jats:inline-formula><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mo stretchy=\"false\">[</mml:mo><mml:mrow><mml:mn>0</mml:mn><mml:mo>,</mml:mo><mml:mi>T</mml:mi></mml:mrow><mml:mo stretchy=\"false\">]</mml:mo></mml:mrow></mml:math></jats:inline-formula>, according to the Lyapunov-like synthesis. To mitigate the impact of initial state errors, a dynamically changing boundary layer is introduced, along with a series to deal with the unknown error upper bounds. Finally, two simulation examples prove the correctness of the proposed control method.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"8 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Requirement analysis in medical phantom development: a survey tool approach with an illustrative example of a multimodal deformable pelvic phantom","authors":"Marie Wegner, Jonte Schmiech, Eve Sobirey, Dieter Krause, Elisabetta Gargioni","doi":"10.3389/fphy.2024.1416601","DOIUrl":"https://doi.org/10.3389/fphy.2024.1416601","url":null,"abstract":"IntroductionMedical phantoms play a crucial role in medical imaging and therapy. However, the successful development of these phantoms heavily relies on a comprehensive understanding of the requirements specific to each application.MethodsIn this paper, we emphasize the significance of requirement analysis in medical phantom development and develop a novel approach for gathering and classifying requirements specific for phantom development.ResultsThe implemented survey tool is designed to accommodate the diverse needs of stakeholders involved in phantom development, including medical staff, physicists, engineers, and product developers. To validate the effectiveness of the approach, we conduct the development of a multimodal deformable pelvic phantom, providing insights into the process and its applicability.DiscussionThe results demonstrate the utility and reliability of our approach in systematically gathering, categorizing, and prioritizing requirements, thus facilitating the streamlined and efficient development of medical phantoms.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"10 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compact freeform near-eye display system design enabled by optical-digital joint optimization","authors":"Huiming Xu, Tong Yang, Dewen Cheng, Yongtian Wang","doi":"10.3389/fphy.2024.1440129","DOIUrl":"https://doi.org/10.3389/fphy.2024.1440129","url":null,"abstract":"The near-eye display (NED) systems, designed to project content into the human eye, are pivotal in the realms of augmented reality (AR) and virtual reality (VR), offering users immersive experiences. A small volume is the key for a fashionable, easy-to-wear, comfortable NED system for industrial and consumer use. Freeform surfaces can significantly reduce the system volume and weight while improving the system specifications. However, great challenges still exist in further reducing the volume of near-eye display systems as there is also a limit when using only freeform optics. This paper introduces a novel method for designing compact freeform NED systems through a powerful optical–digital joint design. The method integrates a geometrical freeform optical design with deep learning of an image compensation neural network, addressing off-axis nonsymmetric structures with complex freeform surfaces. A design example is presented to demonstrate the effectiveness of the proposed method. Specifically, the volume of a freeform NED system is reduced by approximately 63% compared to the system designed by the traditional method, while still maintaining high-quality display performance. The proposed method opens a new pathway for the design of a next-generation ultra-compact NED system.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":"1 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}