Identifying Promising Candidate Radiotherapy Protocols via GPU-GA in-silico

Around half of all cancer patients, world-wide, will receive some form of radiotherapy (RT) as part of their treatment. And yet, despite the rapid advance of high-throughput screening to identify successful chemotherapy drug candidates, there is no current analogue for RT protocol screening or discovery at any scale. Here we introduce and demonstrate the application of a high-throughput/high-fidelity coupled tumour-irradiation simulation approach, we call "GPU-GA", and apply it to human breast cancer analogue - EMT6/Ro spheroids. By analysing over 9.5 million candidate protocols, GPU-GA yields significant gains in tumour suppression versus prior state-of-the-art high-fidelity/-low-throughput computational search under two clinically relevant benchmarks. By extending the search space to hypofractionated areas (> 2 Gy/day) yet within total dose limits, further tumour suppression of up to 33.7% compared to state-of-the-art is obtained. GPU-GA could be applied to any cell line with sufficient empirical data, and to many clinically relevant RT considerations

High-energy-resolution grazing emission X-ray fluorescence applied to the characterization of thin Al films on Si

The grazing emission X-ray fluorescence (GEXRF) technique was applied to the analysis of different Al films, with nominal thicknesses in the range of 1 nm to 150 nm, on Si wafers. In GEXRF the sample volume from which the fluorescence intensity is detected is restricted to a near-surface region whose thickness can be tuned by varying the observation angle. This is possible because of the refraction of the fluorescence X-rays and the quite long emission paths within the probed sample. By recording the X-ray fluorescence signal for different shallow emission angles, defined relatively to the flat, smooth sample surface, the deposited Al surface layers of the different samples could be well characterized in terms of layer thickness, layer density, oxidation and surface roughness. The advantages offered by synchrotron radiation and the employed wavelength-dispersive detection setup were profited from. The GEXRF results retrieved were confirmed by complementary measurements. The experimental setup, the principles and advantages of GEXRF and the analysis of the recorded angular intensity profiles will be discussed in details

Grazing angle X-ray fluorescence from periodic structures on silicon and silica surfaces

Various 3-dimensional nano-scaled periodic structures with different configurations and periods deposited on the surface of silicon and silica substrates were investigated by means of the grazing incidence and grazing emission X-ray fluorescence techniques. Apart from the characteristics which are typical for particle- and layer-like samples, the measured angular intensity profiles show additional periodicity-related features. The latter could be explained by a novel theoretical approach based on simple geometrical optics (GO) considerations. The new GO-based calculations were found to yield results in good agreement with experiment, also in cases where other theoretical approaches are not valid, e.g., periodic particle distributions with an increased surface coverage

Research into ultrasonic and hydrodynamic cavitation phenomena in a hydraulic system

У статті описано процеси ультразвукової кавітації в гідравлічному резервуарі та гідродинамічної кавітації у шестеренному насосі. Виникнення зазначених процесів підтверджено експериментальними дослідженнями при використанні резервуара і насоса з прозорої пластмаси. Доведено, що кавітаційна система, створена за оригінальним проектом, є корисною для генерування явища ультразвукової кавітації. Також показано, що метод PIV-візуалізації, який полягає в спеціальному освітленні прозорих об'єктів і записи структури потоку крізь ці об'єкти за допомогою швидкісної відеокамери, при вивченні явища кавітації досить ефективний. Візуально встановлено взаємодію ультразвуку та гідродинамічної кавітації. У свою чергу, виникнення ультразвукової кавітації в резервуарі викликає дегазацію масла, що подається в насос, яке зменшує гидродинамическую кавітацію у внутрішніх каналах і зазорах. Це свідчить про позитивний вплив ультразвукової кавітації на роботу насоса та гідравлічної системи в цілому. Представлена робота є прикладом ефективної співпраці між дослідниками Вроцлавського університету науки і технологій (Польська Республіка) і Національного технічного університету України “Київського політехнічного інституту імені Ігоря Сікорського”.The article describes the course of the ultrasonic cavitation in a hydraulic tank and the hydrodynamic cavitation in a gear pump. The course of those phenomena was confirmed in experimental tests carried out with the use of a tank and a pump made of transparent plastics. It has been proved that the oscillator-cavitation system made according to the original project is useful to in-duce the phenomenon of ultrasonic cavitation. It has also been shown that the PIV visualization method, consisting in a special sys-tem of illuminating transparent objects and recording the flow through those objects with a fast camera, is useful for the studying of the cavitation phenomena. A visible interaction between the ultrasonic and the hydrodynamic cavitation was observed. The induction of ultrasonic cavitation in the tank causes degassing of the oil, and the degassed oil supplying the pump reduces the hydrodynamic cavitation in its internal channels and clearances. This is an example of beneficial effects of the ultrasonic cavitation on the operation of a pump and a hy-draulic system. The presented work is an example of effective co-operation between the communities of Wroclaw University of Science and Technol-ogy and Igor Sikorsky Kiyv Politechnic Institute, National Technical University of Ukraine.В статье описываются процессы ультразвуковой кавитации в гидравлическом резервуаре и гидродинамической кавитации в шестеренном насосе. Возникновение указанных процессов подтверждено экспериментальными исследованиями при использовании резервуара и насоса из прозрачной пластмассы. Доказано, что кавитационная система, созданная по оригинальному проекту, полезна для генерирования явления ультразвуковой кавитации. Также показано, что метод PIV-визуализации, который заключается в специальном освещении прозрачных объектов и записи структуры потока через эти объекты с помощью скоростной видео камеры, при изучении явления кавитации весьма эффективен. Визуально установлено взаимодействие ультразвука и гидродинамической кавитации. В свою очередь, возникновение ультразвуковой кавитации в резервуаре вызывает дегазацию масла, подаваемого в насос, которое уменьшает гидродинамическую к авитацию во внутренних каналах и зазорах. Это свидетельствует о положительном воздействииу льтразвуковой кавитации на работу насоса и гидравлической системы в целом. Представленная работа является примером эффективного сотрудничества между исследователями Вроцлавского университета науки и технологий (Польская Республика) и Национального технического университета Украины “Киевского политехнического института имени Игоря Сикорского”

The basic propositions on defect numbers, root numbers and indices of linear operators

Abstract: In this work, we use the notion of the measure of noncompactness in order to establish some results concerning the class of semi-Fredholm and Fredholm operators. Further, we apply the results we obtained to prove the invariance of the Schechter essential spectrum on Banach spaces by means of polynomially compact perturbations

Subshell-selective x-ray studies of radiative recombination of U92+{\mathrm{U}}^{92+} ions with electrons for very low relative energies

Radiative recombination (RR) into the K shell and L subshells of U92+ ions interacting with cooling electrons has been studied in an x-ray RR experiment at the electron cooler of the Experimental Storage Ring at GSI. The measured radiative recombination rate coefficients for electron-ion relative energies in the range 0–1000 meV demonstrate the importance of relativistic effects. The observed asymmetry of the measured K-RR x-ray emission with respect to the cooling energy, i.e., zero average relative velocity (⟨vrel⟩=0), are explained by fully relativistic RR calculations. With our new approach, we show that the study of the angular distribution of RR photons for different relative energies opens new perspectives for detailed understanding of the RR of ions with cooling electrons in cold magnetized plasma

Application of the high-resolution grazing-emission x-ray fluorescence method for impurities control in semiconductor nanotechnology

We report on the application of synchrotron radiation based high-resolution grazing-emission x-ray fluorescence (GEXRF) method to measure low-level impurities on silicon wafers. The presented high-resolution GEXRF technique leads to direct detection limits of about 10¹²  atoms/cm². The latter can be presumably further improved down to 10⁷  atoms/cm² by combining the synchrotron radiation-based GEXRF method with the vapor phase decomposition preconcentration technique. The capability of the high-resolution GEXRF method to perform surface-sensitive elemental mappings with a lateral resolution of several tens of micrometers was probed