Exercise and the brain: a mechanical model for pulsation on flow of cerebrospinal fluid

Exchange of molecules between cerebrospinal fluid (CSF) and brain cells contributes to brain function and protection from dementia, but the route by which CSF is brought close enough to the neural tissue to be exchanged by extracellular diffusion is not clear. Exogenous molecules injected into CSF are carried along channels outside arteries and reach the basement lamina that surrounds the dense capillary network. Transport of solutes by diffusion along the basement lamina, a gel of macromolcules about 100 nm thick, would be too slow; bulk flow in a static geometry would require unphysiologically high pressures. However, it is known that the pulsation of blood aids transport of CSF, and we hypothesized that this is because the pulsation intermittently squeezes the pericapillary lamina. In a primitive mimicry, we have tested whether intermittent squeezing increases flow through an agar gel. In all but one of 216 tests, pulsation caused a reversible increase, sometimes by a factor of 100 or more. The enhancement was greatest for frequencies 5-11 Hz and, over the tested range of pressure heads (20 - 50 cmH2O), was greatest for the lowest pressure. The results suggest one reason why exercise slows the aging of the brain.

Rate control for therapeutic applications in Internet of Bio-Nano Things using molecular communication: A survey

Molecular communication is transmitting and receiving chemical signals using molecules and is an interdisciplinary field between nanotechnology, biology, and communication. Molecular communication can be used for connecting bio-nano things. The connected nano-things build a nano-network. Transport mechanisms in molecular communication include free diffusion, gap junction channels, molecular motors, self-propelling microorganisms like bacteria and random collision of mobile nano-things. Free diffusion is the most widely used transport mechanism in the literature. Brownian motion is always available and its energy consumption is zero. This paper explores the therapeutic applications of rate control in the Internet of Bio-Nano Things and reviews the recent trends and advancements in the field of molecular communication. These methods aim to guarantee the desired rate of drug molecules at the target site and overcome the side effects of excessive emission.

MODERN METHODS OF TESTING AND INFORMATION SECURITY PROBLEMS IN IoT

This article analyzes the technology of the internet of things, ie its architecture, communication standards, threats to security and safety, methods and types of testing devices of the internet of things. In short, the architectures proposed by ITU-T and IWF, IEEE standards for Internet of Things, LPWAN standards, four levels of security (devices/gateways, network/transport, services and applications), components according to test methods, performance, loading, security, etc.

DYNAMICS OF POLLUTION LEVEL OF URBANIZED TERRITORIES

The article is devoted to the study of changes in the intensity of traffic flows in the street canyons of Kyiv and to determine the dynamics of the intensity of emissions of major pollutants during the day. Due to the rapid growth of the vehicle fleet, there is a significant congestion of the street and road network of cities, which leads to a set of environmental problems. One of the such problems is air pollution with harmful substances. Object of the study: dynamics of pollution of city streets Purpose of the study: study of changes in traffic intensity during the day and assessment of the dynamics of the level pollution of the cities road network. Method of the study: statistical methods, cluster analysis. The change in the level of pollution of city streets during the day depends on dynamic factors, namely the intensity and quality of the traffic flow, meteorological conditions and so on. It is established that the most dangerous intervals of the day will be "peak" periods during which the maximum values of traffic intensity are observed. The article examines the patterns of distribution of traffic intensity during the day and on the basis of determining the environmental performance of real vehicles, technical and operational characteristics of which correspond to the characteristics of "efficient" cars of the corresponding category, determines the daily distribution of emissions of major pollutants. Thus, the obtained results can be used in determining the concentrations of pollutants in the street canyons of cities, which will make operational predictions of the level of air pollution. KEY WORDS: STREET ROAD NETWORK, TRANSPORT FLOWS, TRAFFIC INTENSITY, STREET CANYON, VEHICLE, POLLUTION LEVEL.

The Problem of Shaping the Capacity of Sovereign Powers of a State in the Digital Age

The global architecture of computer networks poses a security dilemma: while modern information and communication technologies allow adversaries to challenge the exclusive power of states over “his own” cyberspace, following traditional notions of sovereignty, respectively, may limit the ability of states to actively counter challenges and threats in global networks. The aim of the study is to determine the possible scope of application of the traditional territorial concept of sovereignty to the activities of states in cyberspace. The article shows that regarding the activities of states and individuals in cyberspace, the scope of the principle of sovereignty is determined by the practical imperatives of states and depends on the sphere of interstate and cross-border interactions affected. Therefore, for example, for the purposes of warfare, there are three levels at which objects for destruction will be determined: physical network, logical network, network user. Other criteria are important for developers, operators and network analysts, and, according to a number of proposals, a global network can include up to seven levels (physical, data transfer, network, transport, session, data, applications). The article demonstrates that despite the exceptional nature of the powers and jurisdictions of the state in relation to the physical level of cyberspace, its logical and social levels are open to cross-border manifestations of the jurisdiction of other states on the basis of the proximity criterion. That is, for those cases when states can establish a real connection with digital objects or online personalities, and, accordingly, exercise authority.

Análise de precisão e acurácia de métodos de posicionamento em tempo real na determinação de desníveis

O uso do GNSS (Global Navigation Satellite System) vem se difundindo nas mais distintas aplicações, e o método de posicionamento em tempo real tem sido uma forma de determinação de coordenadas de veemente importância em diversas áreas da engenharia. Com o progresso da ciência e da tecnologia, novos equipamentos vêm sendo desenvolvidos, proporcionando uma melhora na precisão e a acurácia destes levantamentos, permitindo sua aplicação em monitoramento de linhas de costa, execução de levantamentos hidrográficos e cadastrais, entre outros. O presente artigo avalia a acurácia e precisão de alguns destes métodos de posicionamento em tempo real, como: o o RTK via NTRIP (Network Transport of RTCM Via Internet Protocol) e o RTG (Real Time Gipsy). A área de pesquisa localizou-se na Diretoria de Hidrografia e Navegação (DHN), em Niterói/RJ, permitindo a realização de levantamentos simultâneos com 03 equipamentos. Como resultado dos desníveis realizados, os erros altimétricos médios apresentados foram de 0,0608m para o NTRIP e 0,4332m para o RTG. Em relação as precisões, os valores médios calculados foram de 0,0869m para o NTRIP e 0,4246m para o RTG. Dessa forma, o NTRIP obteve melhores resultados para o experimento realizado, tanto na precisão quanto na acurácia, considerando-se todas as variáveis impostas pela metodologia adotada. O rastreio NTRIP perdeu algumas correções diferenciais devido a problemas de conectividade do telefone celular com o rastreador. O rastreio RTG não apresentou problemas quanto ao recebimento das correções diferenciais em todo o experimento.