物理最新文献

{"title":"Conformational properties of strictly two-dimensional equilibrium polymers.","authors":"J P Wittmer, A Cavallo, A Johner","doi":"10.1140/epje/s10189-025-00505-3","DOIUrl":"https://doi.org/10.1140/epje/s10189-025-00505-3","url":null,"abstract":"<p><p>Two-dimensional monodisperse linear polymer chains are known to adopt for sufficiently large chain lengths N and surface fractions <math><mi>ϕ</mi></math> compact configurations with fractal perimeters. We show here by means of Monte Carlo simulations of reversibly connected hard disks (without branching, ring formation and chain intersection) that polydisperse self-assembled equilibrium polymers with a finite scission energy E are characterized by the same universal exponents as their monodisperse peers. Consistently with a Flory-Huggins mean-field approximation, the polydispersity is characterized by a Schulz-Zimm distribution with a susceptibility exponent <math><mrow><mi>γ</mi> <mo>=</mo> <mn>19</mn> <mo>/</mo> <mn>16</mn></mrow> </math> for all not dilute systems and the average chain length <math> <mrow><mfenced><mi>N</mi></mfenced> <mo>∝</mo> <mo>exp</mo> <mrow><mo>(</mo> <mi>δ</mi> <mi>E</mi> <mo>)</mo></mrow> <msup><mi>ϕ</mi> <mi>α</mi></msup> </mrow> </math> thus increases with an exponent <math><mrow><mi>δ</mi> <mo>=</mo> <mn>16</mn> <mo>/</mo> <mn>35</mn></mrow> </math> . Moreover, it is shown that <math><mrow><mi>α</mi> <mo>=</mo> <mn>3</mn> <mo>/</mo> <mn>5</mn></mrow> </math> for semidilute solutions and <math><mrow><mi>α</mi> <mo>≈</mo> <mn>1</mn></mrow> </math> for larger densities. The intermolecular form factor F(q) reveals for sufficiently large <math><mfenced><mi>N</mi></mfenced> </math> a generalized Porod scattering with <math><mrow><mi>F</mi> <mrow><mo>(</mo> <mi>q</mi> <mo>)</mo></mrow> <mo>∝</mo> <mn>1</mn> <mo>/</mo> <msup><mi>q</mi> <mrow><mn>11</mn> <mo>/</mo> <mn>4</mn></mrow> </msup> </mrow> </math> for intermediate wavenumbers q consistently with a fractal perimeter dimension <math> <mrow><msub><mi>d</mi> <mi>s</mi></msub> <mo>=</mo> <mn>5</mn> <mo>/</mo> <mn>4</mn></mrow> </math> .</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 6-7","pages":"41"},"PeriodicalIF":1.8,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144688561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Effect of photothermal therapy using PANI-Fe₂O₃-Cys nanocomposites on breast cancer cells with antibacterial activity and cytotoxicity study.","authors":"Huda Abdul Redha Abdullah, Mohanad Q Fahem, Zahraa T Turki, Mohammed H Jawad","doi":"10.1140/epje/s10189-025-00507-1","DOIUrl":"10.1140/epje/s10189-025-00507-1","url":null,"abstract":"<p><p>This study discusses the effect of photothermal therapy using PANI-conductive polymer composites with iron oxide and the amino acid cysteine ​​(Cys) on breast cancer cells. The study focused on the biological and toxicological effects associated with the treatment process and its impact on these cancer cells. The materials were prepared using a very simple chemical oxidation method to produce polymer nanoparticles to which iron and cysteine ​​molecules are attached. These composites were used as therapeutic agents in photothermal therapy, which relies primarily on the process of converting light into heat energy to kill cancer cells. The results showed that photothermal therapy using PANI-Fe₂O₃-Cys composites with near-infrared (NIR) light was significantly more effective in inhibiting breast cancer cells (MDA-MB-231) than using the composites without a laser. Significant changes in the morphology of the cancer cells were observed after treatment, demonstrating the treatment's effectiveness in destroying cancer cells. On the other hand, there was a slight and negligible effect on healthy cells, demonstrating the successful formulation and targeting of the treatment for cancerous tumors. Antibacterial evaluations also demonstrated effective activity against Staphylococcus aureus and Klebsiella bacteria. This study supports the use of composite nanomaterials in photothermal therapy as a targeted treatment for breast cancer, as well as enhancing the effectiveness of this treatment with lasers. It also explains how these materials could be used in future medical applications, particularly in cancer treatment, using methods that are considered less invasive and safer.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 6-7","pages":"40"},"PeriodicalIF":1.8,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144688563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Density-dependent cell migration in the absence of social interactions: a case study of Acanthamoeba castellanii.","authors":"Nasser Ghazi, Mete Demircigil, Olivier Cochet-Escartin, Amandine Chauviat, Sabine Favre-Bonté, Christophe Anjard, Jean-Paul Rieu","doi":"10.1140/epje/s10189-025-00502-6","DOIUrl":"https://doi.org/10.1140/epje/s10189-025-00502-6","url":null,"abstract":"<p><p>Cell migration is often influenced by intercellular or social interactions, ranging from long-range diffusive cues to direct contacts that can trigger biochemical signaling within the cell and affect the cell protruding activity or direction of turns. Here we study the density-dependent migration of the amoeba Acanthamoeba castellanii (Ac), a unicellular eukaryote that moves without social interactions. Using experiments and mean free path theory, we characterize how collisions affect motility parameters in crowded environments. We identify the collision rate as a key parameter linking cell density to the collision-induced reorientation rate, and we show its consistency across multiple independent approaches. Our findings reveal that the intrinsic migration speed remains constant, while persistence time and effective diffusion are entirely governed by collisions. At high densities, cells exhibit nearly ballistic trajectories between collisions, a behavior rarely reported in eukaryotes. These results establish Ac as a minimal model for motility in the absence of biochemical signaling, with implications for testing behaviors in complex crowded environments and pre-jamming dynamics.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 6-7","pages":"42"},"PeriodicalIF":1.8,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144688562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Optically assisted ultrafast spintronics: A review","authors":"Surya Narain Dikshit ,&nbsp;Arshid Nisar ,&nbsp;Brahmdutta Dixit ,&nbsp;Baljinder Kaur ,&nbsp;Alok Kumar Shukla ,&nbsp;Ashutosh Kumar ,&nbsp;Junyang Chen ,&nbsp;Jian-Ping Wang ,&nbsp;Himanshu Fulara ,&nbsp;Brajesh Kumar Kaushik","doi":"10.1016/j.physrep.2025.07.002","DOIUrl":"10.1016/j.physrep.2025.07.002","url":null,"abstract":"<div><div>All-optical switching (AOS) has emerged as a promising technique, utilizing ultrafast lasers with femto or picosecond-pulse durations for modulating magnetization without the use of magnetic fields. This article reviews the state-of-the-art in AOS, focusing on achieving sub-picosecond magnetization reversal in a diverse range of materials, including ferri-magnetic alloys, synthetic ferri-magnets, ferromagnetic multilayers, Heusler alloys, and 2D materials. These materials exhibit remarkable potential for the development of optically driven spintronics devices, offering ultrafast and energy-efficient solutions for circuits and systems, and promising avenues for future photonic integrated circuits. This article also delves into recent advances in opto-spintronic devices, examining their utilization in energy-efficient memory, logic circuits, neuromorphic computing, and terahertz applications. Despite the promising prospects, the integration of opto-spintronic systems into mainstream microelectronic platforms faces several challenges. This review comprehensively discusses these challenges at both the device and system levels, offering insights into potential solutions and future perspectives. By consolidating recent developments and identifying ongoing challenges, this review aims to contribute to the understanding and advancement of AOS in the context of opto-spintronics, paving the way for the next generation of ultrafast and energy-efficient spintronic devices.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1140 ","pages":"Pages 1-46"},"PeriodicalIF":23.9,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144653832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Subharmonic modulational instabilities","authors":"Wen-Rong Sun ,&nbsp;Boris A. Malomed","doi":"10.1016/j.physrep.2025.07.001","DOIUrl":"10.1016/j.physrep.2025.07.001","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Benjamin and Feir in 1967 demonstrated that Stokes waves in deep water are unstable against longitudinal sideband perturbations, and this instability leads to the transformation of an initial periodic wave train into a chain of wave packets. Nowadays, this phenomenon is known as the Benjamin–Feir or modulational instability (MI), with a more general definition. In particular, it may be the &lt;em&gt;subharmonic instability&lt;/em&gt;, when periodic wave trains are unstable against perturbations whose spatial period is a multiple of the underlying wave-train’s period. MI is well known as a ubiquitous effect occurring in diverse fields, such as water waves, plasmas, optics and photonics, and Bose–Einstein condensates (BECs). One can examine the initial (i.e., linear) stage of the MI development by the linearization of the governing equations for small perturbations around the initial (unperturbed) periodic wave train. The linearization ceases to be valid when the growing amplitude of the perturbations becomes comparable to the amplitude of the unperturbed periodic wave trains, which makes investigation of the nonlinear stage of the MI-driven dynamics necessary. It is well known that the nonlinear evolution of MI leads to the formation of localized structures, such as solitons, breathers and rogue waves (RWs). Another essential type of the instability is the high-frequency MI (HFMI), which also originates from the water-wave theory and has been extended to other fields of physics. Similar to the classical MI (alias the low-frequency MI (LFMI)), HFMI may also be viewed as a subharmonic instability of periodic wave trains, but with a very small growth rate and narrow intervals of the Floquet exponents in which HFMI occurs. In this review, we mainly focus on the linear and nonlinear dynamics of periodic wave trains in integrable and nearly integrable systems, including the linear and nonlinear stage of the MI development and investigation of the subharmonic MI. &lt;strong&gt;First&lt;/strong&gt;, we review findings concerning HFMI in fluid dynamics. Subsequently, we address outcomes of HFMI in various physical fields produced by the universal nonlinear Schrödinger (NLS) equation, complemented by a spatially periodic potential. &lt;strong&gt;Second&lt;/strong&gt;, we review discoveries regarding MI of cnoidal waves in nearly integrable and non-integrable systems, drawing insights from the consideration of the long-wave-short-wave resonance equation and universal &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; equation. In addition to that, we summarize analytical results pertaining to MI and modulational stability of cnoidal waves in some integrable systems. &lt;strong&gt;Third&lt;/strong&gt;, we review results for the nonlinear stage of the MI development, by introducing exact correspondence between MI and the formation of localized waves, including RWs with ultra-high peak amplitudes in the baseband-MI regime, and the formation of RWs in the zero-wave","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1139 ","pages":"Pages 1-62"},"PeriodicalIF":23.9,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"On degree-dependent topological study of line graph of some antiviral COVID-19 drugs.","authors":"Shibsankar Das, Arti Kumari, Jayjit Barman","doi":"10.1140/epje/s10189-025-00503-5","DOIUrl":"https://doi.org/10.1140/epje/s10189-025-00503-5","url":null,"abstract":"<p><p> A topological index is a numerical value that correlates with a chemical structure. A degree-based topological index of drug molecular structures is beneficial for researchers investigating in the fields of medicals and pharmaceuticals because it is significant for testing the physicochemical properties of drugs. Graph theory has proven to be quite useful in this field of study. Graph analysis reveals insights into chemical structures. In physical chemistry, a line graph has multiple applications. This article focuses on the topological characterization of a line graph for antiviral COVID-19 drugs, namely Nirmatrelvir, Molnupiravir, Thalidomide, Theaflavin, Remdesivir, Ritonavir, Chloroquine, Hydroxychloroquine, Arbidol and Lopinavir. The computation of degree-based topological indices is carried out using their M-polynomials. Numerical values of topological indices of line graphs and geometric representations of the polynomials are shown graphically. A comparative study between the obtained values of the line graph and the values of an actual graph is presented through numerical and graphical representation. Furthermore, we conduct a QSPR analysis between the degree-based topological indices of the line graph of certain COVID-19 drugs and their physicochemical properties using curvilinear regression models. A comparison is made between the squared correlation coefficients derived from our curvilinear regression models and those obtained from earlier research. These findings may aid the applicability of newly developed drugs of similar kind, in predicting their physicochemical properties and in improving the associated QSPR studies and hence pave a way to improve treatments against the COVID-19 disease.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 6-7","pages":"39"},"PeriodicalIF":1.8,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Label-free metabolic imaging and energy costs in Chlamydomonas.","authors":"Martine Boccara, Katia Wostrikoff, Benjamin Bailleuil, Claude Boccara","doi":"10.1140/epje/s10189-025-00499-y","DOIUrl":"10.1140/epje/s10189-025-00499-y","url":null,"abstract":"<p><p>We developed a label-free optical microscopy method to study movements of different frequencies and amplitudes within a cell. We use optical transmission tomography (OTT) that operates in transmission, and we record the changes of signal values of all the pixels of movies taken for a few seconds (dynamic signal). This signal is a metabolic signal in algae as it decreased in the presence of photosystem II inhibitors or when samples were illuminated at wavelengths where the photoreceptors are poorly operative. We used as model organism Chlamydomonas for which mutants are available. We used a mutant deleted of the chloroplastic gene encoding the large subunit of the Rubisco, ΔrbcL. This mutant is unable to fix atmospheric CO₂ and is devoid of pyrenoid. We compared the dynamic signal between wild-type strain and ΔrbcL mutant of Chlamydomonas grown in dark condition and found it to be 5 to 10 times higher. This mutant overproduced starch, and we tempted to associate the metabolic signal to the cost in ATP_eq consumption for building starch. The method is easy to implement and could be very valuable for studies of phytoplankton in situ or virus-infected cells.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 6-7","pages":"38"},"PeriodicalIF":1.8,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12254062/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144606985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Undecidability in physics: A review","authors":"Álvaro Perales-Eceiza ,&nbsp;Toby Cubitt ,&nbsp;Mile Gu ,&nbsp;David Pérez-García ,&nbsp;Michael M. Wolf","doi":"10.1016/j.physrep.2025.06.004","DOIUrl":"10.1016/j.physrep.2025.06.004","url":null,"abstract":"<div><div>The study of undecidability in problems arising from physics has experienced a renewed interest, mainly in connection with quantum information problems. The goal of this review is to survey this recent development. After a historical introduction, we first explain the necessary results about undecidability in mathematics and computer science. Then we briefly review the first results about undecidability in physics which emerged mostly in the 80s and early 90s. Finally, we focus on the most recent contributions, which we divide in two main categories: many body systems and quantum information problems.</div></div>","PeriodicalId":404,"journal":{"name":"Physics Reports","volume":"1138 ","pages":"Pages 1-29"},"PeriodicalIF":23.9,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Stochastic dynamics in determining fertilization outcomes in plants: effect of gamete number and pollen tube travel path length.","authors":"Aneesa Manzoor, Mahima, Pushkin Kachroo, R Uma Shaanker, Ajeet K Sharma","doi":"10.1140/epje/s10189-025-00501-7","DOIUrl":"https://doi.org/10.1140/epje/s10189-025-00501-7","url":null,"abstract":"<p><p>Plants may enhance seed fitness by favoring fertilization by pollen grains with superior genetic qualities. Pistil traits, such as style length and stigmatic area, are thought to influence this selection, but the mechanisms remain unclear. The impact of stochastic factors on pollen germination time variations is also not fully understood. To investigate this, we simulated a biophysical model using the Monte Carlo method to study how gamete number and pollen tube travel path length affect pollen selection. Our results show that longer travel paths (style lengths) and greater pollen loads on the stigma increase the probability of genetically superior pollen fertilizing ovules. It is because longer styles and more pollen load suppress stochastic effects, promoting seed fitness by favoring superior pollen. We also identify a tradeoff between the benefits of increased path length or pollen load and the resource costs incurred.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 6-7","pages":"37"},"PeriodicalIF":1.8,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144590132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"A python-based novel vertex-edge-weighted modeling framework for enhanced QSPR analysis of cardiovascular and diabetes drug molecules.","authors":"Sezer Sorgun, Asad Ullah","doi":"10.1140/epje/s10189-025-00500-8","DOIUrl":"https://doi.org/10.1140/epje/s10189-025-00500-8","url":null,"abstract":"<p><p>This study advances the quantitative structure-property relationship analysis by leveraging novel vertex-edge-weighted (VEW) molecular graphs to investigate 19 drug molecules commonly used to treat cardiovascular diseases and diabetes. The graphs are constructed by assigning weights to vertices and edges based on atomic properties, enabling a detailed and chemically meaningful representation of molecular structures. Python-based programs were developed to compute degree-based topological indices, which were then analyzed through robust linear regression models to uncover correlations with key physicochemical properties. The results reveal strong and consistent relationships between the computed indices and the physicochemical properties, validating the predictive capability of the proposed approach. Notably, the VEW model demonstrates significant improvements in accuracy and correlation strength over traditional unweighted molecular graph models, underscoring its enhanced ability to capture intricate molecular interactions. This work provides novel insights into the utility of degree-based topological indices in drug design, particularly for cardiovascular and diabetic treatments. By bridging theoretical modeling with practical pharmaceutical applications, it lays a solid foundation for optimizing molecular properties, improving drug efficacy, and accelerating the drug development pipeline. These findings reaffirm the growing significance of computational strategies in advancing precision medicine and pharmaceutical innovation.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"48 6-7","pages":"36"},"PeriodicalIF":1.8,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}