Library transfer between distinct Laser-Induced Breakdown Spectroscopy systems with shared standards

The mutual incompatibility of distinct spectroscopic systems is among the most limiting factors in Laser-Induced Breakdown Spectroscopy (LIBS). The cost related to setting up a new LIBS system is increased, as its extensive calibration is required. Solving the problem would enable inter-laboratory reference measurements and shared spectral libraries, which are fundamental for other spectroscopic techniques. In this work, we study a simplified version of this challenge where LIBS systems differ only in used spectrometers and collection optics but share all other parts of the apparatus, and collect spectra simultaneously from the same plasma plume. Extensive datasets measured as hyperspectral images of heterogeneous specimens are used to train machine learning models that can transfer spectra between systems. The transfer is realized by a pipeline that consists of a variational autoencoder (VAE) and a fully-connected artificial neural network (ANN). In the first step, we obtain a latent representation of the spectra which were measured on the Primary system (by using the VAE). In the second step, we map spectra from the Secondary system to corresponding locations in the latent space (by the ANN). Finally, Secondary system spectra are reconstructed from the latent space to the space of the Primary system. The transfer is evaluated by several figures of merit (Euclidean and cosine distances, both spatially resolved; k-means clustering of transferred spectra). The methodology is compared to several baseline approaches.Comment: 32 pages, 22 figure

Effects of vitamin D3 derivative--calcitriol on pharmacological reactivity of aortic rings in a rodent PCOS model.

Abstract BACKGROUND: The aim of this study was to examine the effects of the hyperandrogenic state in dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS), the vascular responses to different vasoactive agents, and the modulatory role of vitamin D3. METHODS: APCOS model was induced by DHT application in 20 female Wistar rats. Ten of the DHT treated rats simultaneously received calcitriol treatment. After 10 weeks, myographs were used to test the reactivity of isolated thoracic aortic rings to norepinephrine and acetylcholine. Thereafter, the vascular rings were incubated with the NO-synthase blocker (nitro-L-arginine methyl ester) or the cyclooxygenase inhibitor (indomethacin) for 20 min, and the effects of norepinephrine and acetylcholine were re-evaluated. RESULTS: Norepinephrine-induced vasoconstriction was enhanced after DHT treatment, but this effect was attenuated by calcitriol administration. Vasorelaxation of DHT-treated thoracic aortic rings was impaired, but this could be partly reversed by calcitriol application. Impaired NO-dependent vasorelaxation in DHT-treated animals was mostly reversed by concomitant calcitriol administration, but this effect was diminished by prostanoid-dependent vasoconstriction. CONCLUSIONS: These studies show that the enhanced sensitivity to vasoconstrictors and impaired NO-dependent vasorelaxation in hyperandrogenic PCOS rats could be partially reversed by calcitriol treatment

РАЗРАБОТКА КОНЦЕПЦИИ ПОСТРОЕНИЯ АППАРАТНО-ПРОГРАММНОГО КОМПЛЕКСА МОДУЛЬНОЙ КОНСТРУКЦИИ ДЛЯ ОПРЕДЕЛЕНИЯ ХАРАКТЕРИСТИК АНТЕННЫХ СИСТЕМ ПО ИЗМЕРЕНИЯМ В БЛИЖНЕЙ ЗОНЕ

Measuring the amplitude-phase distribution of the radiation field of complex antenna systems on a certain surface close to the radiating aperture allows solving the problem of reconstructing the free-space diagram in the far field and also helps in determining the influence of various structural elements and defects of radiating surfaces on formation of directional diagram. The purpose of this work was to develop a universal hardware-software complex of a modular design aimed for determining the characteristics of wide range of antenna systems in respect of measurements of the amplitude-phase distribution of the radiation field in the near zone.The equations that connect the structure of radiation fields of the antenna system at various distances from it in planar, cylindrical and spherical coordinate systems as well as structural diagrams of the hardware part of measuring complexes have been analyzed.As a result, the concept of constructing a universal hardware-software complex for measuring the radiation field of various types of antenna systems with any type of measurement surface for solving a wide range of applied problems has been developed. A modular structure of hardware and software has been proposed; it allows reconfiguring the complex rapidly in order to measure the characteristics of any particular antenna system at all stages of product development and testing, and also makes the complex economically accessible even for small enterprises and organizations.Измерения амплитудно-фазового распределения поля излучения сложных антенных систем на некоторой поверхности вблизи излучающей апертуры позволяют решить задачи восстановления пространственной диаграммы направленности антенных систем в дальней зоне и определить влияние различных конструктивных элементов и дефектов излучающих поверхностей на формирование диаграммы направленности. Целью данной работы явилась разработка универсального аппаратно-программного комплекса модульной конструкции для определения характеристик широкого круга антенных систем по измерениям амплитудно-фазового распределения поля излучения в ближней зоне. Проанализированы описанные в литературе уравнения, связывающие структуру полей излучения антенной системы на различных расстояниях от нее в планарной, цилиндрической и сферической системах координат, а также структурные схемы аппаратной части измерительных комплексов,В результате разработана концепция построения универсального аппаратно-программного комплекса для измерения поля излучения различных типов антенных систем с любым типом поверхности измерения для решения широкого круга прикладных задач. Предложена модульная структура аппаратной части комплекса и программного обеспечения, что позволяет оперативно переконфигурировать комплекс для измерения характеристик любой конкретной антенной системы на всех стадиях разработки и испытаний изделия, а также делает комплекс экономически доступным даже для небольших предприятий и организаций

ПРИМЕНЕНИЕ СТАТИСТИЧЕСКИХ МЕТОДОВ ДЛЯ ОЦЕНКИ МЕТРОЛОГИЧЕСКИХ ХАРАКТЕРИСТИК РАДИОГОЛОГРАФИЧЕСКИХ ИЗМЕРИТЕЛЬНЫХ КОМПЛЕКСОВ

Practical application of the radio-holographic method for measuring the characteristics of antennas, especially when conducting acceptance testing of systems, requires an adequate assessment of the errors in the recovery of long-range characteristics. These errors appear to be a superposition composed of various sources, having different nature, different time characteristics and different degrees of influence on the final result. The purpose of this work was the development of a practical technique for determining the influence of random errors in measuring the amplitude-phase distribution of the field of the antenna required for the accuracy of restoring long-range characteristics (primarily the antenna pattern) of the antenna, the proposed technique being based only on processing the experimental results obtained with this measuring complex.A practical method for determining the influence of random errors in measuring the amplitude-phase distribution of the field of the antenna under study on the accuracy of restoring its long-range characteristics (primarily the directional pattern) on the basis of correlation and spectral analysis has been developed and experimentally confirmed. The main advantage of the developed method in comparison with the use of mathematical modeling is that the estimation of the accuracy of the reconstruction of the directivity diagrams is based on the results of processing experimental data obtained on a specific measuring complex and does not a priori impose any preliminary requirements on the statistical parameters of errors. The developed procedure for estimating the influence of random errors can be used to develop a methodology for metrological certification of measuring systems as measuring instruments.Практическое применение радиоголографического метода измерения характеристик антенн, в особенности при проведении приемочных испытаний систем, требует адекватной оценки погрешностей восстановления дальнезонных характеристик. Указанные погрешности являются суперпозицией слагаемых от различных источников, имеющих различную природу, различные временные характеристики и различные степени влияния на конечный результат. Целью данной работы являлась разработка практической методики определения влияния случайных погрешностей измерения амплитудно-фазового распределения поля иccледуемой антенны на точность восстановления дальнезонных характеристик (в первую очередь диаграммы направленности) антенны, причем предлагаемая методика основана только на обработке экспериментальных результатов, полученных на данном измерительном комплексе.Разработана и экспериментально подтверждена практическая методика определения влияния случайных погрешностей измерения амплитудно-фазового распределения поля исследуемой антенны на точность восстановления ее дальнезонных характеристик (в первую очередь диаграммы направленности) на основе корреляционного и спектрального анализа. Основным преимуществом разработанной методики по сравнению с использованием математического моделирования является то, что оценка точности восстановления диаграмм направленности проводится по результатам обработки экспериментальных данных, полученных на конкретном измерительном комплексе, и не накладывает априори никаких предварительных требований на статистические параметры погрешностей. Разработанная процедура оценки влияния случайных погрешностей может использоваться для разработки методики метрологической аттестации измерительных комплексов как средств измерения

ПРАКТИЧЕСКАЯ РЕАЛИЗАЦИЯ АППАРАТНО-ПРОГРАММНОГО КОМПЛЕКСА ДЛЯ ПЛАНАРНЫХ ИЗМЕРЕНИЙ ХАРАКТЕРИСТИК АНТЕНН В БЛИЖНЕЙ ЗОНЕ

Directional patterns measurement of antennas is carried out by the methods of far and near zone. Measurements in the far zone are straightforward; however they have a number of disadvantages. Near zone measurement methods are free from measurement shortcomings in the far zone, but it requires complex and expensive equipment for its implementation.Earlier, the authors have developed a concept of hardware and software modular design complex to determine antenna system characteristics as per measurements in the near zone. This concept assumes creation of a universal measuring complex to investigate various types of antenna systems with any type of measurement surface (plane, cylinder, sphere) in order to solve a wide range of applied problems. The purpose of this work lies in practical implementation of a variant of this measuring complex for measurement along the plane and determination of its metrological (hardware and software) capabilities.A working experimental sample of hardware and software complex for measuring the characteristics of antenna systems that realizes a radio-holographic method for measuring along a plane has been developed, created and practically tested. A preliminary estimation of errors in amplitude and phase measurements in the dynamic range of 45 dB and a comparison of the characteristics of several types of antennas measured in far and near zones have been made. Algorithms have been developed, a software for processing, storing and graphical display of measurement results has been created.Измерение диаграмм направленности антенн проводится методами дальней и ближней зоны. Измерения в дальней зоне являются прямыми, однако обладают рядом недостатков. Ближнезонные способы измерения свободны от недостатков измерений в дальней зоне, но требует для своей реализации сложной и дорогостоящей аппаратуры и оборудования.Ранее авторами разработана концепция построения аппаратно-программного комплекса модульной конструкции для определения характеристик антенных систем по измерениям в ближней зоне. Концепция предполагает создание универсального измерительного комплекса для исследования различных типов антенных систем с любым типом поверхности измерения (плоскость, цилиндр, сфера) для решения широкого круга прикладных задач. Целью данной работы явилась практическая реализация варианта измерительного комплекса для измерения по плоскости и определение его метрологических (аппаратных и программных) возможностей.Разработан, создан и практически опробован действующий экспериментальный образец аппаратно-программного комплекса для измерения характеристик антенных систем, реализующий радиоголографический метод измерения по плоскости. Проведена предварительная оценка погрешностей измерения амплитуды и фазы в динамическом диапазоне 45 дБ и сравнение характеристик нескольких типов антенн, измеренных в дальней и ближней зонах. Разработаны алгоритмы, создано программное обеспечение по обработке, хранению и графическому отображению результатов измерения

Reduced Estradiol-Induced Vasodilation and Poly-(ADP-Ribose) Polymerase (PARP) Activity in the Aortas of Rats with Experimental Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder characterized by hyperandrogenism and insulin resistance, both of which have been connected to atherosclerosis. Indeed, an increased risk of clinical manifestations of arterial vascular diseases has been described in PCOS. On the other hand endothelial dysfunction can be detected early on, before atherosclerosis develops. Thus we assumed that vascular dysfunction is also related directly to the hormonal imbalance rather than to its metabolic consequences. To detect early functional changes, we applied a novel rodent model of PCOS: rats were either sham operated or hyperandrogenism was achieved by implanting subcutaneous pellets of dihydrotestosterone (DHT). After ten weeks, myograph measurements were performed on isolated aortic rings. Previously we described an increased contractility to norepinephrine (NE). Here we found a reduced immediate relaxation to estradiol treatment in pre-contracted aortic rings from hyperandrogenic rats. Although the administration of vitamin D3 along with DHT reduced responsiveness to NE, it did not restore relaxation to estradiol. Poly-(ADP-ribose) polymerase (PARP) activity was assessed by poly-ADP-ribose immunostaining. Increased PAR staining in ovaries and circulating leukocytes from DHT rats showed enhanced DNA damage, which was reduced by concomitant vitamin D3 treatment. Surprisingly, PAR staining was reduced in both the endothelium and vascular smooth muscle cells of the aorta rings from hyperandrogenic rats. Thus in the early phase of PCOS, vascular tone is already shifted towards vasoconstriction, characterized by reduced vasorelaxation and vascular dysfunction is concomitant with altered PARP activity. Based on our findings, PARP inhibitors might have a future perspective in restoring metabolic disorders in PCOS

Grb2 monomer-dimer equilibrium determines normal versus oncogenic function

The adaptor protein growth factor receptor-bound protein 2 (Grb2) is ubiquitously expressed in eukaryotic cells and involved in a multitude of intracellular protein interactions. Grb2 plays a pivotal role in tyrosine kinase-mediated signal transduction including linking receptor tyrosine kinases to the Ras/mitogen-activated protein (MAP) kinase pathway, which is implicated in oncogenic outcome. Grb2 exists in a constitutive equilibrium between monomeric and dimeric states. Here we show that only monomeric Grb2 is capable of binding to SOS and upregulating MAP kinase signalling and that the dimeric state is inhibitory to this process. Phosphorylation of tyrosine 160 (Y160) on Grb2, or binding of a tyrosylphosphate-containing ligand to the SH2 domain of Grb2, results in dimer dissociation. Phosphorylation of Y160 on Grb2 is readily detectable in the malignant forms of human prostate, colon and breast cancers. The self-association/dissociation of Grb2 represents a switch that regulates MAP kinase activity and hence controls cancer progression

Novel regulation of Ras proteins by direct tyrosine phosphorylation and dephosphorylation

Somatic mutations in the RAS genes are frequent in human tumors, especially in pancreatic, colorectal, and non-small-cell lung cancers. Such mutations generally decrease the ability of Ras to hydrolyze GTP, maintaining the protein in a constitutively active GTP-bound form that drives uncontrolled cell proliferation. Efforts to develop drugs that target Ras oncoproteins have been unsuccessful. Recent emerging data suggest that Ras regulation is more complex than the scientific community has believed for decades. In this review, we summarize advances in the "textbook" view of Ras activation. We also discuss a novel type of Ras regulation that involves direct phosphorylation and dephosphorylation of Ras tyrosine residues. The discovery that pharmacological inhibition of the tyrosine phosphoprotein phosphatase SHP2 maintains mutant Ras in an inactive state suggests that SHP2 could be a novel drug target for the treatment of Ras-driven human cancers

Intrinsic Structural Disorder Confers Cellular Viability on Oncogenic Fusion Proteins

Chromosomal translocations, which often generate chimeric proteins by fusing segments of two distinct genes, represent the single major genetic aberration leading to cancer. We suggest that the unifying theme of these events is a high level of intrinsic structural disorder, enabling fusion proteins to evade cellular surveillance mechanisms that eliminate misfolded proteins. Predictions in 406 translocation-related human proteins show that they are significantly enriched in disorder (43.3% vs. 20.7% in all human proteins), they have fewer Pfam domains, and their translocation breakpoints tend to avoid domain splitting. The vicinity of the breakpoint is significantly more disordered than the rest of these already highly disordered fusion proteins. In the unlikely event of domain splitting in fusion it usually spares much of the domain or splits at locations where the newly exposed hydrophobic surface area approximates that of an intact domain. The mechanisms of action of fusion proteins suggest that in most cases their structural disorder is also essential to the acquired oncogenic function, enabling the long-range structural communication of remote binding and/or catalytic elements. In this respect, there are three major mechanisms that contribute to generating an oncogenic signal: (i) a phosphorylation site and a tyrosine-kinase domain are fused, and structural disorder of the intervening region enables intramolecular phosphorylation (e.g., BCR-ABL); (ii) a dimerisation domain fuses with a tyrosine kinase domain and disorder enables the two subunits within the homodimer to engage in permanent intermolecular phosphorylations (e.g., TFG-ALK); (iii) the fusion of a DNA-binding element to a transactivator domain results in an aberrant transcription factor that causes severe misregulation of transcription (e.g. EWS-ATF). Our findings also suggest novel strategies of intervention against the ensuing neoplastic transformations