Ion irradiation effect (Аr+, E = 20-40 keV) on the mechanical properties and microstructure of aluminum V95 alloy

The effect of 20-40 keV Ar+ ion irradiation on the mechanical properties and structural and phase state of hot-pressed profiles 6 mm thick made of an V95 alloy (Al-Zn-Mg-Cu system) after artificial aging has been studied. Irradiation (without causing heating) at fluences of 2∙1015 cm-2 and 1∙1016 cm-2 has been revealed to increase the relative elongation by 5%, without changing the strength characteristics. Electron microscopy examination has showed that irradiation has an effect on the state of the subgrain structure of the alloy. Irradiation at these fluences results in partial enlargement of the subgrain structure, and at higher fluence of 9.4∙1016 cm-2 it completely transforms the structure into coarse-grained one. At a distance of 150 µm from the irradiated surface, there is a slight increase in the subgrain size. The irradiation changes the morphology of Al6(Fe,Mn) intermetallic compounds in both the surface layer and the sample volume; namely, it sharply decreases the bulk density of lath-shaped intermetallic compounds and increases the density of the equiaxed ones. The degree of influence depend on the irradiation mode. © 2020 Institute of Physics Publishing. All rights reserved.This work was supported in part by RFBR grant № 19-08-00802-а

Microstructure of 1469 aluminum alloy after severe plastic deformation and ion irradiation

The effect of accelerated Ar+ ion beams with an energy of 10 keV on the microstructure and phase composition in 1469 alloy (Al-Cu-Li-Ag-Mg-Zr-Sc) initially subjected to severe plastic deformation (SPD) has been investigated by transmission electron microscopy. Irradiation has been found to result in the formation of a predominantly recrystallized nanocrystalline or fully recrystallized submicrocrystalline structure in the alloy, depending on the ion fluence. The irradiation liquidates the banded structure found in the alloy after SPD. Therefore, the structural elements (nanofragments, nanograins, submicrocrystals) are distributed uniformly in the volume of the irradiated sample. In addition, irradiation increases the volume fraction and the size bimodality of heterogeneously-generated Т2-phase particles. The mechanism of nucleation and growth of excess phases has been proposed. The structure changes at a higher rate than it does during a long low-temperature annealing process, and structural changes are observed at a distance of ~200 μm from the surface, which considerably exceeds the projected ion range (~ 10 nm). © 2020 Institute of Physics Publishing. All rights reserved.This work was supported in part by RFBR grant № 18-08-00942-а

Возможности фотодинамической терапии при эритроплазии Кейра

The review is dedicated to the analysis of the effectiveness of the treatment of erythroplasia of Queyrat (EQ) using photodynamic therapy (PDT). Particular attention is paid to the relationship between EQ and human papillomavirus (HPV) infection. The data of various researchers are presented, confirming the correlation between the development of the EQ and the HPV infection, however, it is noted that due to the small number of studies it is difficult to draw reliable conclusions on the presence and strength of this connection. The mechanisms of PDT involved in the implementation of both the antitumor effect in the treatment of EQ and the antiviral effect against HPV are considered. The data of 12 clinical studies and observations of the results of PDT of the EQ conducted in recent years are analyzed. An analysis of literature data showed that in the treatment of EQ, one of the two photosensitizers is usually used locally: 5-aminolevulinic acid or 5-aminolevulinic acid methyl ester. The treatment parameters in all the analyzed studies were similar: exposure to the ointment for 3–5 hours followed by irradiation with a light dose of 37–105 J/cm2. The number of PDT courses in different studies varied from 1 to 19. The effectiveness of treatment varied widely in different studies and clinical observations. Most studies have demonstrated high efficacy of PDT with complete regression in 36–83% (100% in one study) and a relapse-free follow-up period of up to 51 months. However, there were also individual clinical observations of patients in whom the treatment with the method of PDT was ineffective. It is possible that the described results were associated with improperly selected regimes of PDT or a large lesion area. Most authors especially note a very good cosmetic effect and a complete absence of scars after the treatment. Thus, PDT is an effective and promising method for the treatment of EQ that requires, however, a more thorough development of the application regimen and a deeper study of the antitumor and antiviral components of the mechanism of action.Обзор посвящен анализу эффективности лечения эритроплазии Кейра методом фотодинамической терапии (ФДТ). Особое внимание уделено вопросам взаимосвязи эритроплазии Кейра с инфицированием вирусом папилломы человека (ВПЧ). Приведены данные исследований, подтверждающие корреляцию между развитием заболевания и инфицированием ВПЧ, отмечено, что в связи с небольшим количеством исследований сложно делать достоверные выводы о наличии и силе этой связи. Рассмотрены механизмы ФДТ, участвующие в реализации как противоопухолевого эффекта при лечении эритроплазии Кейра, так и противовирусного действия в отношении ВПЧ. Проанализированы данные 12 клинических исследований и наблюдений результатов ФДТ при эритроплазии Кейра, проведенных в последние годы. Установлено, что при лечении заболевания, как правило, используют местно один из двух фотосенсибилизаторов: 5-аминолевулиновую кислоту (5-АЛК) или ее метиловый эфир. Параметры лечения во всех исследованиях были близки: экспозиция мази продолжительностью от 3 до 5 ч с последующим облучением со световой дозой 37 - 105 Дж/см2 . Количество курсов ФДТ в разных исследованиях составляло от 1 до 19. Эффективность лечения широко варьировала в разных исследованиях и клинических наблюдениях. Большинство исследований демонстрировало высокую эффективность ФДТ с полной регрессией образования в 36 - 83% наблюдений и продолжительностью безрецидивного периода до 51 мес. Имелись и отдельные клинические наблюдения, в которых ФДТ оказалась неэффективна. Возможно, описанные результаты были связаны с неправильно подобранными режимами ФДТ или большой площадью поражения. Большинство авторов отмечают хороший косметический эффект ФДТ и полное отсутствие рубцов после проведенного лечения. Таким образом, ФДТ является эффективным и перспективным методом лечения эритроплазии Кейра, однако, требующим тщательной отработки режимов применения и более глубокого изучения противоопухолевого и противовирусного компонентов механизма действия

Photodynamic therapy opportunities for the treatment of erythroplasia of Queyrat

The review is dedicated to the analysis of the effectiveness of the treatment of erythroplasia of Queyrat (EQ) using photodynamic therapy (PDT). Particular attention is paid to the relationship between EQ and human papillomavirus (HPV) infection. The data of various researchers are presented, confirming the correlation between the development of the EQ and the HPV infection, however, it is noted that due to the small number of studies it is difficult to draw reliable conclusions on the presence and strength of this connection. The mechanisms of PDT involved in the implementation of both the antitumor effect in the treatment of EQ and the antiviral effect against HPV are considered. The data of 12 clinical studies and observations of the results of PDT of the EQ conducted in recent years are analyzed. An analysis of literature data showed that in the treatment of EQ, one of the two photosensitizers is usually used locally: 5-aminolevulinic acid or 5-aminolevulinic acid methyl ester. The treatment parameters in all the analyzed studies were similar: exposure to the ointment for 3–5 hours followed by irradiation with a light dose of 37–105 J/cm2. The number of PDT courses in different studies varied from 1 to 19. The effectiveness of treatment varied widely in different studies and clinical observations. Most studies have demonstrated high efficacy of PDT with complete regression in 36–83% (100% in one study) and a relapse-free follow-up period of up to 51 months. However, there were also individual clinical observations of patients in whom the treatment with the method of PDT was ineffective. It is possible that the described results were associated with improperly selected regimes of PDT or a large lesion area. Most authors especially note a very good cosmetic effect and a complete absence of scars after the treatment. Thus, PDT is an effective and promising method for the treatment of EQ that requires, however, a more thorough development of the application regimen and a deeper study of the antitumor and antiviral components of the mechanism of action