49 research outputs found
Silicon nanocrystals for nonlinear optics and secure communications
No full textSilicon nanocrystals (Si-nc) are reviewed here for their interesting optical applications. On the one hand, they do exhibit quantum confinement effects. This allows turning silicon into a light-emitting material where luminescence can be excited by electrical injection. On the other hand, small sizes, large surfaces, and dielectric mismatch between the core and the surrounding matrix increase dramatically the nonlinear optical coefficients. This allows using Si-nc as a nonlinear material in different waveguide configurations. In this paper, we discuss specifically two different applications of Si-nc: (i) as a nonlinear material in various devices, e.g., in bistable optical cavities, in waveguide optical mode monitors that are based on two-photon excited luminescence detection, and in wavelength shifters by using four-wave mixing (FWM); (ii) as an entropy source for quantum random number generation, the key device for cryptography
The Concept of Information Asymmetry as a Theoretical Substantiation of the Phenomenon of Public Non-Financial Reporting
No full textThe global trend of widespread of public non-financial reporting makes the researchers face the task of finding its scientific basis. A unified theoretical and methodological basis of the concept of public non-financial reporting can be able to form the system of categories, laws, postulates and allow to implement effectively the processes of norm-setting, standardization and harmonization of public non-financial reporting with financial reporting. The purpose of the article is to provide the rationale for the choice of concept of information asymmetry as a fundamental theoretical basis to justify the phenomenon of public non-financial reporting. In the study the author applied the following research methods: analysis, synthesis, induction, deduction, comparison, generalization, and a systems approach. The article provides the results of analysis of extension of public non-financial reporting and identification of the problems of its application in Russian firms. The author systematizes the theoretical concepts be able to explain a phenomenon of public non-financial reporting: concept of sustainable development, the stakeholder theory, the doctrine of fair contracts. The author also demonstrates that the concept of information asymmetry is unifying for all of them and can be used to explain the voluntary adoption of obligations for additional disclosure of non-financial measurers by business. There is a need for a further scientific discussion of ideas about the implementation of public non-financial reporting as a prescriptive institutional or voluntary signaling mechanism, problem of its standardization, the counteract unfair usage of non-financial reporting to strengthen the negative effects of information asymmetry and the reallocation of market goods
Sensitivity and Limit of Detection of biosensors based on ring resonators
No full textIn this work, we present a study of the Sensitivity (S) and Limit of Detection (LOD) of microring based photonic biosensors as a function of the waveguide composition and dimensions. The target is Aflatoxin, which is a toxin of major concern for south Europe dairy industry. The sensing device is based on an array of multiple SiON microring resonators, fiber-coupled to both an 850 nm VCSEL and a silicon photodetectors, packaged with a microfluidic circuit. Volumetric sensing with glucose–water solutions of various concentrations yields a best sensitivity of 112 nm/RIU. To link these results to the Limit of Detection of the sensors, we also measured the noise of our experimental readout system and then calculated the LOD of our sensors. We found a best value of LOD of 1.6 × 10−6 RIU (referred to volumetric sensing). Finally, we detected Aflatoxin in solutions of various concentrations (down to 1.58 nM) by functionalized sensors. The functionalization is based on a wet silanization and specific DNA-aptamer binding on the chip. Reproducibility and re-usability of the sensor are investigated by several chemical treatments. Optimum procedure allows multiple sequential measurements with a good endurance. This work was supported by the FP7 EU project “Symphony” (Grant agreement no.: 610580). Keywords: Biosensor, Whispering Gallery Mode, Ring resonator, Aflatoxin, Limit of Detection, Sensitivit
Microring Resonators and Silicon Photonics
No full textSilicon Photonics is the technological to face the future challenges in data communications and processing. This technology follows the same paradigm as the technological revolution of the integrated circuit industry, that is, the miniaturization and the standardization. One of the most important building blocks in Silicon Photonics is the microresonator, a circular optical cavity, which enables many different passive and active optical functions. Here, we will describe the new physics of the intermodal coupling, which occurs when multi radial mode resonators are coupled to waveguides, and of the optical chaos, which develops in coupled sequence of resonators. In addition, an application of resonators in the label-free biosensing will be discussed
Теория учета: современные проблемы и структурно-логическаямодель развития
No full textIntroduction, Purpose. The current stage of development in accounting is characterized by the methodological fragmentation of accounting theory, poor link between accounting theory and the development of social sciences, inability of accounting to cope with challenges of modern economy. These may be a reason for denial of scientific foundations of accounting theory. The purpose of the article is to provide a systematic analysis of the contemporary academic papers devoted to the problems of the development of accounting theory and methodology of accounting in order to formulate a structural-logical model for the development of a level of particular theoretical schemes of accounting. Methods. In the study the author applied the following research methods: analysis, synthesis, induction, deduction, comparison, generalization, and a systems approach. Results. The article provides the results of analysis and systemization of modern problems in accounting theory. The author considers the transformation peculiarities of methodology of accounting as a social and applied science, makes a proposal about how to organize research in the field of accounting theory in accordance with the Academician V. Stepin concept of scientific knowledge organization and formulates a structural-logical model of development of accounting theory concepts as a level of particular theoretical schemes. Discussions. There is a need for a further scientific discussion of ideas about the types of accounting as particular theoretical schemes based, on the one hand, on accounting theory, and on judgments and postulates taken from related fields of social sciences, on the other hand
DEFINING THE SUBJECT AND OBJECTS OF MANAGEMENT ACCOUNTING IN THE CONTEXT OF ACCOUNTING THEORY DEVELOPMENT
No full textThe current stage of management accounting development is characterized by the lack of balance between its theory and practical applications. One of the key features of this process is that management accounting theory along with its development in the context of the accounting theory and related science is not researched deep enough. The purpose of the article is to define the subject of the management accounting and its objects through the development of accounting theory. In the study the following research methods were used: analysis, synthesis, induction, deduction, comparison, generalization, and a system approach. The author studies the evolution of capital as a subject of accounting theory, considers a modern approach to capital as an object of integratedreporting, defines the subject of management accounting. The article proves that management accounting is a research direction of accounting theory as a science of higher level, provides the classification of management accounting objects based on the forms of capital and the way they are related to the state and changes in capital. This classification can be used to make charts of accounts for management accounting, based on the forms and transformations of capital in the system of double-entry or triple-entry bookkeeping
Experimental bladder regeneration using a poly-L-lactide/silk fibroin scaffold seeded with nanoparticle-labeled allogenic bone marrow stromal cells
No full textNatalia M Yudintceva,1 Yulia A Nashchekina,1,2 Miralda I Blinova,1 Nadezhda V Orlova,3 Alexandr N Muraviov,3 Tatiana I Vinogradova,3 Magomed G Sheykhov,3 Elena Y Shapkova,3 Dmitriy V Emeljannikov,3 Petr K Yablonskii,3,4 Igor A Samusenko,5 Anastasiya L Mikhrina,6 Artem V Pakhomov,7 Maxim A Shevtsov1,7,8 1Department of Cell Culture, Institute of Cytology of the Russian Academy of Sciences (RAS), 2Nanotechnology and Telecommunications, Institute of Physics, Peter the Great St Petersburg Polytechnic University, 3Department of Urology, Federal State Institution Saint Petersburg Research Institute of Phthisiopulmonology, Ministry of Health of Russia, 4Faculty of Medicine, Federal State Budgetary Institute, 5Department of Pathology, Federal State Budgetary Institute “Nikiforov Russian Centre of Emergency and Radiation Medicine” of the Ministry of Health of Russia, 6Department of Pathomorphology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Science, 7Department of Radiology, Federal Almazov North-West Medical Research Center, 8Department of Experimental Medicine, First I.P. Pavlov State Medical University of St Petersburg, St Petersburg, Russia Abstract: In the present study, a poly-L-lactide/silk fibroin (PL-SF) bilayer scaffold seeded with allogenic bone marrow stromal cells (BMSCs) was investigated as a potential approach for bladder tissue engineering in a model of partial bladder wall cystectomy in rabbits. The inner porous layer of the scaffold produced from silk fibroin was designed to promote cell proliferation and the outer layer produced from poly-L-lactic acid to serve as a waterproof barrier. To compare the feasibility and efficacy of BMSC application in the reconstruction of bladder defects, 12 adult male rabbits were divided into experimental and control groups (six animals each) that received a scaffold seeded with BMSCs or an acellular one, respectively. For BMSC tracking in the graft in in vivo studies using magnetic resonance imaging, cells were labeled with superparamagnetic iron oxide nanoparticles. In vitro studies demonstrated high intracellular incorporation of nanoparticles and the absence of a toxic influence on BMSC viability and proliferation. Following implantation of the graft with BMSCs into the bladder, we observed integration of the scaffold with surrounding bladder tissues (as detected by magnetic resonance imaging). During the follow-up period of 12 weeks, labeled BMSCs resided in the implanted scaffold. The functional activity of the reconstructed bladder was confirmed by electromyo­graphy. Subsequent histological assay demonstrated enhanced biointegrative properties of the PL-SF scaffold with cells in comparison to the control graft, as related to complete regener­ation of the smooth muscle and urothelium tissues in the implant. Confocal microscopy studies confirmed the presence of the superparamagnetic iron oxide nanoparticle-labeled BMSCs in newly formed bladder layers, thus indicating the role of stem cells in bladder regeneration. The results of this study demonstrate that application of a PL-SF scaffold seeded with allogenic BMSCs can enhance biointegration of the graft in vivo and support bladder tissue regeneration and function. Keywords: bladder, bone marrow stromal cells, scaffold, superparamagnetic iron oxide nanoparticles, tissue engineering, stem cell
Integrated Assessment of Economic Security in a Resource Region
No full textThe article provides a comparative analysis of existing approaches to assessing regional economic
security and proposes an original procedure for integrated assessment of economic security in resource
regions. It includes an assessment of economic security thresholds based on Russia’s strategic development
priorities in comparison to the level of developed countries, as well as trend and multivariate statistical analyses
that help to identify crucial imbalances that threaten economic development in a region. The assessment
is based on data from Krasnoyarsk krai. We have identified several economic security paradoxes, namely, an
imbalanced development of human assets and the environment, the industrial sector and hi-tech business, as
well as disequilibrium in financial security, which are forcing the region to transform from an advanced industrial
territory with a diversified economy into a “national storehouse” that has predominantly mining monoenterprises
and to end up in the trap of technological inferiority
Integrated Assessment of Economic Security in a Resource Region
No full textThe article provides a comparative analysis of existing approaches to assessing regional economic
security and proposes an original procedure for integrated assessment of economic security in resource
regions. It includes an assessment of economic security thresholds based on Russia’s strategic development
priorities in comparison to the level of developed countries, as well as trend and multivariate statistical analyses
that help to identify crucial imbalances that threaten economic development in a region. The assessment
is based on data from Krasnoyarsk krai. We have identified several economic security paradoxes, namely, an
imbalanced development of human assets and the environment, the industrial sector and hi-tech business, as
well as disequilibrium in financial security, which are forcing the region to transform from an advanced industrial
territory with a diversified economy into a “national storehouse” that has predominantly mining monoenterprises
and to end up in the trap of technological inferiority
