Dynamic fracture of a dissimilar chain

International audienceIn this paper, we study the dynamic fracture of a dissimilar chain composed of two different mass-spring chains and connected with other springs. The propagation of the fault (crack) is realized under externally applied moving forces. In comparison with a homogeneous double chain, the considered structure displays some new essential features of steady-state crack propagation. Specifically, the externally applied forces are of a different strength, unlike a static case, and should be appropriately chosen to satisfy the equilibrium of the structure. Moreover, there exists a gap in the range of crack speeds where the steady-state fracture cannot occur. We analyse the admissibility of solutions for different model parameters and crack speeds. We complement analytical findings with numerical simulations to validate our results

Frictionless Motion of Lattice Defects

Energy dissipation by fast crystalline defects takes place mainly through the resonant interaction of their cores with periodic lattice. We show that the resultant effective friction can be reduced to zero by appropriately tuned acoustic sources located on the boundary of the body. To illustrate the general idea, we consider three prototypical models describing the main types of strongly discrete defects: dislocations, cracks and domain walls. The obtained control protocols, ensuring dissipation-free mobility of topological defects, can be also used in the design of meta-material systems aimed at transmitting mechanical information

On stress singularity near the tip of a crack with surface stresses

In the framework of the simplified linear Gurtin–Murdoch surface elasticity we discuss a singularity of stresses and displacements in the vicinity of a mode III crack. We show that inhomogeneity in surface elastic properties may significantly affect the solution and to change the order of singularity. We also demonstrate that implicitly or explicitly assumed symmetry of the problem may also lead to changes in solutions. Considering various loading and symmetry conditions we show that the stresses may have logarithmic or square root singularity or be bounded in the vicinity of a crack tip

Аптамеры для диагностики и лечения глиальных опухолей человека

Purpose of the study: to evaluate the feasibility of using functional analogues of protein antibodies – dNa/ RNa aptamers in diagnostics, treatment and prognosis of human brain glial tumors.Material and Methods. The relevant literature sources were searched in scopus, Web of science, pubmed, elibrary with inclusion of publications from 2000 to 2023. sixty articles are presented in the review.Results. The analysis of the literature devoted to classification, diagnostics and therapy of brain glioblastomas was carried out and the feasibility of using for in vivo diagnostics and therapy of this disease aptamers, which are molecular recognition elements based on DNA/RNA oligonucleotides, capable of binding to the given molecular targets and distinguishing even separate functional groups in them, was studied. A list of aptamers to human glial brain tumors and their molecular targets that can be used for diagnostics and therapy of glioblastoma, including tumor imaging by pet/ct, mRi, plasmon resonance, fluorescence and confocal microscopy, etc., is presented. literature data suggest that DNA/RNA aptamers can be used to search for circulating tumor cells in the blood of glioblastoma patients, to target therapeutic drugs to the tumor and to inhibit tumor growth.Conclusion. Brain glioblastoma is a heterogeneous tumor consisting of cells at different stages of malignancy and, accordingly, with a different set of oncogenes. For this reason, a multitarget strategy that includes combined suppression of angiogenesis, invasion, metastasis, proliferation and survival of tumor cells should be proposed for the therapy of this disease. DNA/RNA aptamers tailored to key proteins involved in oncogenic transformation may be suitable candidates for the implementation of multitarget therapy for brain glioblastoma.Цель исследования – оценить возможность использования функциональных аналогов белковых антител – ДНК/РНК-аптамеров в диагностике, лечении и прогнозировании развития глиальных опухолей головного мозга человека.Материал и методы. Поиск соответствующих источников литературы проводили в системах scopus, Web of science, pubmed, elibrary с включением публикаций с 2000 по 2023 г. В обзоре представлены данные из 60 статей.Результаты. Проведен анализ литературы, посвященной классификации, диагностике и терапии глиобластом головного мозга и изучению возможности использования для in vivo диагностики и терапии этого заболевания аптамеров, которые представляют собой молекулярные распознающие элементы на основе ДНК/РНК-олигонуклеотидов, способных связываться с заданными молекулярными мишенями и различать в них даже отдельные функциональные группы. Приведен список из аптамеров к глиальным опухолям головного мозга человека и их молекулярных мишеней, которые могут быть использованы для диагностики и терапии глиобластомы, в том числе для визуализации опухоли методами ПЭТ/КТ, МРТ, плазмонного резонанса, флуоресцентной и конфокальной микроскопии и др. Данные литературы свидетельствуют о том, что с помощью ДНК/РНК-аптамеров можно осуществлять поиск циркулирующих опухолевых клеток в крови больных глиобластомой, адресную доставку к опухоли терапевтических препаратов и подавлять опухолевый рост.Заключение. Глиобластома головного мозга – гетерогенная опухоль, состоящая из клеток, находящихся на разной стадии злокачественности и, соответственно, с различным набором онкогенов. Именно поэтому для терапии этого заболевания должна быть предложена мультитаргетная стратегия, которая включает в себя комбинированное подавление ангиогенеза, инвазии, метастазирования, пролиферации и выживаемости опухолевых клеток. Подходящими кандидатами для реализации мультитаргетной терапии глиобластомы головного мозга могут стать ДНК/РНК-аптамеры, подобранные к ключевым белкам, участвующим в онкогенной трансформации

Insights into the innate immunity of the Mediterranean mussel Mytilus galloprovincialis

<p>Abstract</p> <p>Background</p> <p>Sessile bivalves of the genus <it>Mytilus </it>are suspension feeders relatively tolerant to a wide range of environmental changes, used as sentinels in ecotoxicological investigations and marketed worldwide as seafood. Mortality events caused by infective agents and parasites apparently occur less in mussels than in other bivalves but the molecular basis of such evidence is unknown. The arrangement of Mytibase, interactive catalogue of 7,112 transcripts of <it>M. galloprovincialis</it>, offered us the opportunity to look for gene sequences relevant to the host defences, in particular the innate immunity related genes.</p> <p>Results</p> <p>We have explored and described the Mytibase sequence clusters and singletons having a putative role in recognition, intracellular signalling, and neutralization of potential pathogens in <it>M. galloprovincialis</it>. Automatically assisted searches of protein signatures and manually cured sequence analysis confirmed the molecular diversity of recognition/effector molecules such as the antimicrobial peptides and many carbohydrate binding proteins. Molecular motifs identifying complement C1q, C-type lectins and fibrinogen-like transcripts emerged as the most abundant in the Mytibase collection whereas, conversely, sequence motifs denoting the regulatory cytokine MIF and cytokine-related transcripts represent singular and unexpected findings. Using a cross-search strategy, 1,820 putatively immune-related sequences were selected to design oligonucleotide probes and define a species-specific Immunochip (DNA microarray). The Immunochip performance was tested with hemolymph RNAs from mussels injected with <it>Vibrio splendidus </it>at 3 and 48 hours post-treatment. A total of 143 and 262 differentially expressed genes exemplify the early and late hemocyte response of the <it>Vibrio</it>-challenged mussels, respectively, with AMP trends confirmed by qPCR and clear modulation of interrelated signalling pathways.</p> <p>Conclusions</p> <p>The Mytibase collection is rich in gene transcripts modulated in response to antigenic stimuli and represents an interesting window for looking at the mussel immunome (transcriptomes mediating the mussel response to non-self or abnormal antigens). On this basis, we have defined a new microarray platform, a mussel Immunochip, as a flexible tool for the experimental validation of immune-candidate sequences, and tested its performance on <it>Vibrio</it>-activated mussel hemocytes. The microarray platform and related expression data can be regarded as a step forward in the study of the adaptive response of the <it>Mytilus </it>species to an evolving microbial world.</p

Supersonic kinks and solitons in active solids

International audienc