Dust remobilization in fusion plasmas under steady state conditions

The first combined experimental and theoretical studies of dust remobilization by plasma forces are reported. The main theoretical aspects of remobilization in fusion devices under steady state conditions are analyzed. In particular, the dominant role of adhesive forces is highlighted and generic remobilization conditions - direct lift-up, sliding, rolling - are formulated. A novel experimental technique is proposed, based on controlled adhesion of dust grains on tungsten samples combined with detailed mapping of the dust deposition profile prior and post plasma exposure. Proof-of-principle experiments in the TEXTOR tokamak and the EXTRAP-T2R reversed-field pinch are presented. The versatile environment of the linear device Pilot-PSI allowed for experiments with different magnetic field topologies and varying plasma conditions that were complemented with camera observations.Comment: 16 pages, 11 figures, 3 table

Dissociative recombination and electron-impact de-excitation in CH photon emission under ITER divertor-relevant plasma conditions

For understanding carbon erosion and redeposition in nuclear fusion devices, it is important to understand the transport and chemical break-up of hydrocarbon molecules in edge plasmas, often diagnosed by emission of the CH A^2\Delta - X^2\Pi Ger\"o band around 430 nm. The CH A-level can be excited either by electron-impact or by dissociative recombination (D.R.) of hydrocarbon ions. These processes were included in the 3D Monte Carlo impurity transport code ERO. A series of methane injection experiments was performed in the high-density, low-temperature linear plasma generator Pilot-PSI, and simulated emission intensity profiles were benchmarked against these experiments. It was confirmed that excitation by D.R. dominates at T_e < 1.5 eV. The results indicate that the fraction of D.R. events that lead to a CH radical in the A-level and consequent photon emission is at least 10%. Additionally, quenching of the excited CH radicals by electron impact de-excitation was included in the modeling. This quenching is shown to be significant: depending on the electron density, it reduces the effective CH emission by a factor of 1.4 at n_e=1.3*10^20 m^-3, to 2.8 at n_e=9.3*10^20 m^-3. Its inclusion significantly improved agreement between experiment and modeling

Chiral peculiar properties of self-organization of diphenylalanine peptide nanotubes: Modeling of structure and properties

The structure and properties of diphenylalanine peptide nanotubes based on phenylalanine were investigated by various molecular modeling methods. The main approaches were semi-empirical quantum-chemical methods (PM3 and AM1), and molecular mechanical ones. Both the model structures and the structures extracted from their experimental crystallographic databases obtained by X-ray methods were examined. A comparison of optimized model structures and structures obtained by naturally-occurring self-assembly showed their important differences depending on D- and L-chirality. In both the cases, the effect of chirality on the results of self-assembly of diphenylalanine peptide nanotubes was established: peptide nanotubes based on the D-diphenylalanine (D-FF) has high condensation energy E 0 in transverse direction and forms thicker and shorter peptide nanotubes bundles, than that based on L-diphenylalanine (L-FF). A topological difference was established: model peptide nanotubes were optimized into structures consisting of rings, while naturally self-assembled peptide nanotubes consisted of helical coils. The latter were different for the original L-FF and D-FF. They formed helix structures in which the chirality sign changes as the level of the macromolecule hierarchy raises. Total energy of the optimal distances between two units are deeper for L-FF (-1.014 eV) then for D-FF (-0.607 eV) for ring models, while for helix coil are approximately the same and have for L-FF (-6.18 eV) and for D-FF (-6.22 eV) by PM3 method; for molecular mechanical methods energy changes are of the order of 2-3 eV for both the cases. A topological transition between a ring and a helix coil of peptide nanotube structures is discussed: self-assembled natural helix structures are more stable and favourable, they have lower energy in optimal configuration as compared with ring models by a value of the order of 1 eV for molecular mechanical methods and 5 eV for PM3 method. © 2019 Mathematical Biology and Bioinformatics.Part of this work was developed as part of the CICECO-Aveiro Materials Institute project, POCI-01-0145-FEDER-007679 funded from Fundação para a Ciência e a Tecnologia (FCT) Ref. UID/CTM/50011/2013, and funded from national funds through FCT/MEC, and co-funded by FEDER in accordance with the PT2020 Partnership Agreement. P.Z. thanks the project FCT PTDC/QEQ-QAN/6373/2014. S.K. thanks the project FCT PTDC/CTM-CTM/31679/2017

Structures and properties of the self-assembling diphenylalanine peptide nanotubes containing water molecules: Modeling and data analysis

The structures and properties of the diphenylalanine (FF) peptide nanotubes (PNTs), both L-chiral and D-chiral (L-FF and D-FF) and empty and filled with water/ice clusters, are presented and analyzed. DFT (VASP) and semi-empirical calculations (HyperChem) to study these structural and physical properties of PNTs (including ferroelectric) were used. The results obtained show that after optimization the dipole moment and polarization of both chiral type L-FF and D-FF PNT and embedded water/ice cluster are enhanced; the water/ice cluster acquire the helix-like structure similar as L-FF and D-FF PNT. Ferroelectric properties of tubular water/ice helix-like cluster, obtained after optimization inside L-FF and D-FF PNT, as well of the total L-FF and D-FF PNT with embedded water/ice cluster, are discussed. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.This work was partially supported by the Fundacão para a Ciência e a Tecnologia (FCT, Portugal) through project UID/CTM/50025/2013 and UIDB/50011/2020 & UIDP/50011/2020. P.Z. and S.K. are grateful to the FCT (Portugal) through the project “BioPiezo,” PTDC/CTM–CTM/31679/2017 (CENTRO-01-0145-FEDER-031679). The theoretical and computational parts of the study was completed within the framework of the non-commercial Agreement on scientific and technical cooperation between Institute of Mathematical Problems of Biology (IMPB) of KIAM RAS and Department of Physics and I3N institution of the University of Aveiro, Portugal. Part of this work was funded by national funds (OE), through FCT (Portugal), in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19

Photoelectronic Properties of Chiral Self-Assembled Diphenylalanine Nanotubes: A Computational Study

Peptide nanotubes (PNT) of diphenylalanine (FF) have attracted considerable attention from researchers in the last decades. The chirality of FF monomers determines the kinetics of PNTs’ self-assembly and their morphology. The helical symmetry of PNTs causes significant intrinsic polarization and endows them with a unique combination of mechanical, electronic, and optical properties, as well as a strong piezoelectric effect useful for various applications. In this work, we used a combination of computer modeling and quantum chemical calculations to study the photoelectronic properties of FF PNTs of different chiralities. Using semiempirical methods implemented in the HyperChem and MOPAC packages, we calculated HOMO and LUMO energy levels and a band gap and their variations under the action of external and internal electric fields. We demonstrated that the photoelectronic properties of l- and d-FF PNTs are slightly different and may be related to the intrinsic electric field arising due to the internal polarization. The band gap of FF PNTs is within the ultraviolet range (400–250 nm) and can be tuned by an external electric field. These results open a way to create FF PNT-based solar-blind ultraviolet photodetectors and other electro-optic and electronic devices. © 2023 by the authors.Fundação para a Ciência e a Tecnologia, FCT; Russian Foundation for Basic Research, РФФИ: 19-01-00519_A, 20-51-53014_GFEN_AThe authors are grateful to the Russian Foundation for Basic Research, RFBR (grants 19-01-00519_A and 20-51-53014_GFEN_A). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020, supported through the FCT/MEC (PIDDAC). Part of this work was supported by national funds (OE), through FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of article 23, of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July. The computational parts of the study were completed within the framework of the noncommercial agreement on scientific and technical cooperation between the Institute of Mathematical Problems of Biology (IMPB)—branch of KIAM RAS, Russia and the Department of Physics of the University of Aveiro, Portugal. The authors are grateful for the opportunity to perform calculations using the computer cluster of IMPB RAS and the K-60 hybrid supercomputer installed at the KIAM RAS Shared Use Center

Preoperative 3D modeling splenectomy in patients with primary immune thrombocytopenia

СПЛЕНЭКТОМИЯТРОМБОЦИТОПЕНИЯ /ХИРТОМОГРАФИЯ РЕНТГЕНОВСКАЯ КОМПЬЮТЕРНАЯ3D МОДЕЛИРОВАНИЕГЕМОСТАЗВАСКУЛЯРИЗАЦИЯЦель. Изучить эффективность предоперационного 3-D моделирования на основе анализа данных мультиспиральной компьютерной томографии при выполнении лапароскопической спленэктомии по поводу первичной иммунной тромбоцитопении. Материал и методы. Пациентка, 55 лет с диагнозом идиопатическая тромбоцитопеническая пурпура, рецидивирующее течение. В течение 10 лет она наблюдалась и проходила неоднократные курсы консервативного лечения, принимала ежедневно до 60 мг преднизолона. Уровень тромбоцитов крови снижался ниже 30?109 /л. В связи с неэффективностью консервативного лечения была показана спленэктомия. Выполнена мультиспиральная компьютерная томография с болюсным контрастированием. На основе полученных данных в системе "Автоплан" была построена цветная 3-D модель области оперативного вмешательства. Система по планированию оперативного вмешательства объединяет медицинское оборудование, внутристационарную сеть архивирования и обмена данными с рабочими станциями врачей с возможностью использования на компьютерах и мобильных устройствах непосредственно в операционной. Пациентке выполнена лапароскопическая гибридная спленэктомия. Результаты. Согласно 3-D модели, у пациентки выявлен магистральный тип васкуляризации селезенки. Дистальная часть хвоста поджелудочной железы не доходила до ворот селезенки на 1,5 см. Добавочные селезенки и перипроцесс отсутствовали. Данные модели 3-D подтвердились интраоперационно и позволили выполнить лапароскопическую гибридную спленэктомию без технических трудностей прецизионно с минимальной кровопотерей. Послеоперационный период протекал без осложнений. Пациентка выписана на 5 сутки в удовлетворительном состоянии. Показатели уровня тромбоцитов достигли референтных значений (356?109 /л). Заключение. Предоперационное 3-D моделирование позволяет хирургу заранее планировать оперативное вмешательство с учетом знания индивидуальных топографо-анатомических особенностей области предстоящей операции. Знание индивидуальных особенностей васкуляризации селезенки и топографии поджелудочной железы в ее воротах позволяет прецизионно выделять и легировать сосуды, что повышает качество гемостаза, а также уменьшает вероятность травмы поджелудочной железы. Дооперационная визуализация добавочных селезенок повышает радикальность операции.Objectives. To explore the possibilities of preoperative 3D modelling and analysis system based on multislice computed tomography data, to evaluate its effectiveness in performing laparoscopic splenectomy for the primary immune thrombocytopenia. Methods. A female patient, (55 yrs) with the diagnosis of idiopathic thrombocytopenic purpura, recurrent course. For 10 years she had been observed and underwent the numerous courses of conservative treatment; she also took daily 60 mg of prednisolone. The blood platelet levels reduced below 30?109/l. The splenectomy was indicated due to the failure of conservative treatment. Multislice computed tomography with contrast bolus was performed. For preoperative planning a color 3D model of the surgical site was created on the basis of the obtained data in the "Autoplan" system. Systems giving the ability to plan surgical intervention combines the medical equipment, PACS system (picture archiving and communication system) available onsite advanced image-viewing workstations that can guide physicians; the ability to view images from various workstations via the network including the navigation enabling physicians to create the accurate and realistic models from stereo cameras, and to use computers as well as mobile computing devices directly in the operating room. The patient was underwent laparoscopic hybrid splenectomy. Results. According to the 3D model a main type of vascularization of the spleen was revealed. The distal part of the pancreatic tail did not reach (1.5 cm) the gate of the spleen. Accessory spleens and periprotsess were absent. The data of 3D model were confirmed intraoperatively and allowed performing a laparoscopic hybrid splenectomy without technical difficulties precisely with a minimal blood loss. The postoperative period was uneventful. The patient was discharged on the 5th day in a satisfactory condition. The parameters of platelet level have reached the reference values (356?109/l). Conclusion. Preoperative 3D modelling permits the surgeon to make pre-operative planning and provides him with important information on individual topographic and anatomic features in forthcoming operation sites. The information about the individual characteristics of the splenic vascularization and pancreatic topography in its gate lets to allocate and ligate vessels precisely, that improves the quality of hemostasis and also reduces the probability of the pancreatic injury. Preoperative visualization of accessory spleens increases the radicalism of the surgery

Modeling of Self-Assembled Peptide Nanotubes and Determination of Their Chirality Sign Based on Dipole Moment Calculations

The chirality quantification is of great importance in structural biology, where the differ-ences in proteins twisting can provide essentially different physiological effects. However, this aspect of the chirality is still poorly studied for helix-like supramolecular structures. In this work, a method for chirality quantification based on the calculation of scalar triple products of dipole moments is suggested. As a model structure, self-assembled nanotubes of diphenylalanine (FF) made of L-and D-enantiomers were considered. The dipole moments of FF molecules were calculated using semi-empirical quantum-chemical method PM3 and the Amber force field method. The obtained results do not depend on the used simulation and calculation method, and show that the D-FF nanotubes are twisted tighter than L-FF. Moreover, the type of chirality of the helix-like nanotube is opposite to that of the initial individual molecule that is in line with the chirality alternation rule general for different levels of hierarchical organization of molecular systems. The proposed method can be applied to study other helix-like supramolecular structures. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgments: The authors are grateful to the Russian Foundation for Basic Researches (RFBR): grants №№ 19–01–00519_A and 20-51-53014_GFEN_A. Part of this work (A.K.) was supported by the Ministry of Science and Higher Education of the Russian Federation (grant No. 075-15-2021-588). P.Z., S.K. and A.K. are grateful to the FCT project “BioPiezo”—PTDC/CTM−CTM/31679/2017 (CENTRO-01-0145-FEDER-031679) and to the project CICECO-Aveiro Institute of Materials, refs. UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. Part of this work was funded by national funds (OE), through FCT–Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. A.S. and E.M. are grateful to the the Interdisciplinary Scientific and Educational School of Moscow University “Fundamental and Applied Space Research”

ОПТИМИЗАЦИЯ РАЗМЕЩЕНИЯ ОБЪЕКТОВ С УЧЕТОМ ИХ РЕПЛИКАЦИЙ НА УЗЛАХ РАСПРЕДЕЛЕННОЙ ИНФОРМАЦИОННО-ВЫЧИСЛИТЕЛЬНОЙ СИСТЕМЫ

Предлагается модель размещения объектов на узлах распределенной системы, учитывающаявведение репликаций, параметры объектов и потоков запросов к объектам, характеристики каналов передачи данных и узлов обработки запросов. Формулируется оптимизационная задача распределения объектов на узлах, предлагается алгоритм наискорейшего спуска решения задачи. Проводятся эксперименты, выявляющие закономерности и тренды в изменении параметров функционирования оптимизированной системы

Molecular modeling and computational study of the chiral-dependent structures and properties of the self-assembling diphenylalanine peptide nanotubes, containing water molecules

DFT (VASP) and semi-empirical (HyperChem) calculations for the l- and d-chiral diphenylalanine (l-FF and d-FF) nanotube (PNT) structures, empty and filled with water/ice clusters, are presented and analyzed. The results obtained show that after optimization, the dipole moment and polarization of both chiral type l-FF and d-FF PNT and embedded water/ice cluster are enhanced; the water/ice cluster acquire the helix-like structure similar as l-FF and d-FF PNT. Ferroelectric properties of tubular water/ice helix-like-cluster obtained after optimization inside l-FF and d-FF PNT and total l-FF and d-FF PNT with embedded water/ice cluster are discussed. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.This work was partially supported by the Fundacão para a Ciência e a Tecnologia(FCT, Portugal) through project UID/CTM/50025/2013 and UIDB/50011/2020 & UIDP/50011/2020. P.Z. and S.K. are grateful to the FCT (Portugal) through the project “BioPiezo,” PTDC/CTM–CTM/31679/2017 (CENTRO-01-0145-FEDER-031679). The computational parts of the study was completed within the framework of the non-commercial Agreement on scientific-technical cooperation between Institute of Mathematical Problems of Biology (IMPB) of the Keldysh Institute of Applied Mathematics RAS (KIAM RAS) and Department of Physics and I3N Institution of the University of Aveiro, Portugal

Аналоги соматостатина в лечении кастрационно-резистентного рака предстательной железы: эффективность и переносимость

Castrate-resistant prostate cancer (CRPC) is one of the most complex and currently completely unsolved problems of oncourology. Possible novel treatment of CRPC is administration of Octreotide Long, long-acting somatostatin analogue.In this paper we have shown an experience of treatment with Octreotide Long 30 mg and dexamethasone in 69 CRPC patients from February 2014 to March 2016. We have assessed an efficacy and safety of the therapy. Age of patients ranged from 56 to 89 years, all patients had continued androgen deprivation. Response to the treatment was assessed clinically by the following factors: change in the level of prostate specific antigen (PSA) in serum, dynamics of indicators of general and biochemical blood tests, the level of pain syndrome and improvement in the patient’s quality of life. Total response to reduction and stabilization of PSA level was achieved in 70.9 % of patients. In general, the best results were observed in the group of patients treated with Octreotide Long before first-line chemotherapy with docetaxel. Tolerability of Octreotide Long in combination with dexamethasone in all cases was good. No significant side effects – neither hematological, nor clinical were noted. We also did not register any cases of drug discontinuation due to its intolerance. Одной из наиболее сложных и окончательно не решенных проблем онкоурологии в настоящее время является кастрационно-резистентный рак предстательной железы (КРРПЖ). Возможное направление в его лечении – назначение аналога соматостатина пролонгированного действия Октреотида-лонг.В настоящей работе представлен опыт лечения Октреотидом-лонг 30 мг и дексаметазоном 69 пациентов с КРРПЖ с февраля 2014 г. по март 2016 г., проведена оценка эффективности и безопасности терапии. Возраст пациентов варьировал от 56 до 89 лет, у всех продолжалась андрогенная депривация в постоянном режиме. Ответ на лечение оценивали клинически: по изменению уровня простатического специфического антигена (ПСА) сыворотки крови, динамике показателей общего и биохимического анализов крови, уровню болевого синдрома и улучшению качества жизни пациента. Суммарный ответ по снижению и стабилизации уровня ПСА был достигнут у 70,9 % больных, в целом лучшие результаты наблюдались в группе пациентов, получавших Октреотид-лонг до химиотерапии 1-й линии доцетакселом. Переносимость Октреотида-лонг в комбинации с дексаметазоном во всех случаях была хорошая. Значимых побочных эффектов, как гематологических, так и клинических, не отмечено. Не зарегистрировано отмены препарата из-за непереносимости.