Mathematical modeling of fluid movement inside the eyeball during intravitreal injection

2021 ◽  
pp. 106-109
Author(s):  
D.V. Lipatov ◽  
◽  
S.A. Skladchikov ◽  
N.P. Savenkova ◽  
V.V. Novoderezkin ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Residence Time ◽  
Complex Structure ◽  
Posterior Vitreous Detachment ◽  
Vitreous Body ◽  
Complete Removal ◽  
Intravitreal Injections ◽  
The World

Background. The avalanche-like growth of intravitreal injections in the world has significantly increased interest in the hemodynamics of the processes that occur in the eye when a drug is injected into the vitreous cavity. Every year, the number of intravitreally used drugs and promising areas in which they can be used is growing. This also applies to the creation of new combined medicines and the development of drugs with a long-term therapeutic effect. Aims. Create mathematical model of eyeball to evaluate the movement of the drug substance in it; to estimate the time of the drug's presence in the eye cavity before its complete removal, to characterize the ways of its removal from the eye cavity; to assess the significance of posterior vitreous detachment during the time when the drug is present in the eye cavity; to evaluate the effect on the hydrodynamics of the depth of drug administration. Results. When the drug is administered closer to the center of the eyeball, its residence time increases in comparison with the parietal administration. With a complete posterior detachment of the vitreous body, the time of finding the drug in the eye is prolonged compared to its absence. The obtained results of mathematical modeling of the movement of the drug administered intravitreally cannot be mechanically transferred to the human eye, due to the more complex structure of the latter. Key words: intravitreal injections, vitreous body, mathematic computing.

Application of the method of mathematical modeling for forecasting channel deformations at the underwater crossing of the main pipeline

2020 ◽  
Vol 10 (6) ◽  
pp. 599-609
Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Roughness Coefficient ◽  
Computational Domain ◽  
Channel Deformations ◽  
Geological Surveys ◽  
Kuban River ◽  
The Stability ◽  
Protective Structures

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

scholarly journals COMPLEXITY-BASED ANALYSIS OF THE ALTERATIONS IN THE STRUCTURE OF CORONAVIRUSES

Fractals ◽  
2021 ◽  
Vol 29 (02) ◽  
pp. 2150123
Author(s):  
HAMIDREZA NAMAZI ◽  
ALI SELAMAT ◽  
ONDREJ KREJCAR
Keyword(s):  
Hurst Exponent ◽  
Complex Structure ◽  
Approximate Entropy ◽  
Sample Entropy ◽  
Long Term Memory ◽  
Complex Structures ◽  
Term Memory ◽  
The World ◽  
First Time

The coronavirus has influenced the lives of many people since its identification in 1960. In general, there are seven types of coronavirus. Although some types of this virus, including 229E, NL63, OC43, and HKU1, cause mild to moderate illness, SARS-CoV, MERS-CoV, and SARS-CoV-2 have shown to have severer effects on the human body. Specifically, the recent known type of coronavirus, SARS-CoV-2, has affected the lives of many people around the world since late 2019 with the disease named COVID-19. In this paper, for the first time, we investigated the variations among the complex structures of coronaviruses. We employed the fractal dimension, approximate entropy, and sample entropy as the measures of complexity. Based on the obtained results, SARS-CoV-2 has a significantly different complex structure than SARS-CoV and MERS-CoV. To study the high mutation rate of SARS-CoV-2, we also analyzed the long-term memory of genome walks for different coronaviruses using the Hurst exponent. The results demonstrated that the SARS-CoV-2 shows the lowest memory in its genome walk, explaining the errors in copying the sequences along the genome that results in the virus mutation.

scholarly journals Mathematical Modeling to Perform an Analysis of Social Isolation Periods in the Dissemination of COVID-19

2021 ◽  
Vol 22 (4) ◽  
pp. 595-608
Author(s):  
A. Molter ◽  
R. S. Quadros ◽  
M. Rafikov ◽  
D. Buske ◽  
G. A. Gonçalves
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Mathematical Models ◽  
Social Isolation ◽  
Computer Simulations ◽  
The Other ◽  
Stable Level ◽  
The Social ◽  
The World ◽  
Second Peak

The outbreak of COVID-19 has made scientists from all over the world do not measureefforts to understand the dynamics of the disease caused by this coronavirus. Several mathematical models have been proposed to describe the dynamics and make predictions. This work proposes a mathematical model that includes social isolation of susceptible individuals as a strategy of suppression and mitigation of the disease. The Susceptible-Infectious-Isolated-Recovered-Dead (SIQRD) model is proposed to analyze three important issues about the dynamics of the disease taking into account social isolation: when the isolation should begin? How long to keep the isolation? How to get out of this isolation? To get answers, computer simulations are provided and their results discussed. The results obtained show that beginning social isolation on the 10th or 15th days, after confirmation of the 50th case, and with 70% of the population in isolation, seems to be promising, since the infected curve does not grow much until it enters the isolation and remains at a stable level during the isolation. On the other hand an abrupt release of the social isolation will imply a second peak of infected individuals above the first one, which is not desired. Therefore, the release from social isolation should be gradual.

scholarly journals Determination of the Course of COVID-19 Pandemic Using Modified Logistic Modeling

2021 ◽  
pp. 17-26
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Mortality Rate ◽  
Tract Infection ◽  
Large Population ◽  
High Rate ◽  
The World ◽  
New Type ◽  
Short Time

Introduction: COVID-19 appeared in China at the end of 2019. It then spread all over the world very quickly. The new type of corona virus COVID-19, which causes respiratory tract infection, is destructive with its high rate of transmission and mortality rate. Materials and Methods: In this study, determining the course of the COVID-19 pandemic for next 4 months in Afghanistan with the help of a specially modified mathematical modeling is intended to reveal. Results: results of our study show that the COVID-19 pandemic can affect a large population in Afghanistan in a short time. However, it is possible to reduce the number of cases and deaths very effectively with easy measures. Keywords: COVID-19, precautions, pandemic, logistic mathematical model, Afghanistan.

scholarly journals Analysis and simulation of a mathematical model of tuberculosis transmission in Democratic Republic of the Congo

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Selain Kasereka Kabunga ◽  
Emile F. Doungmo Goufo ◽  
Vinh Ho Tuong
Keyword(s):  
Mathematical Model ◽  
Democratic Republic ◽  
World Health ◽  
Tuberculosis Transmission ◽  
Modeling Analysis ◽  
The World ◽  
Republic Of The Congo ◽  
Health Organization ◽  
Lost To Follow Up

AbstractAccording to the World Health Organization reports, tuberculosis (TB) remains one of the top 10 deadly diseases of recent decades in the world. In this paper, we present the modeling, analysis and simulation of a mathematical model of TB transmission in a population incorporating several factors and study their impact on the disease dynamics. The spread of TB is modeled by eight compartments including different groups, which are too often not taken into account in the projections of tuberculosis incidence. The rigorous mathematical analysis of this model is provided, the basic reproduction number ($\mathcal{R}_{0}$ R 0 ) is obtained and used for TB dynamics control. The results obtained show that lost to follow-up and transferred individuals constitute a risk, but less than the cases carrying germs. Rapidly evolving latent/exposed cases are responsible for the incidence increasing in the short and medium term, while slower evolving latent/exposed cases will be responsible for the persistent long-term incidence and maintenance of TB and delay elimination in the population. The numerical simulations of the model show that, with certain parameters, TB will die out or sensibly reduce in the entire Democratic Republic of the Congo (DRC) population. The strategies on which the DRC’s health system is currently based to fight this disease show their weaknesses because the TB situation in the DRC remains endemic. But monitoring contact, detection of latent individuals and their treatment are actions to be taken to reduce the incidence of the disease and thus effectively control it in the population.

scholarly journals The connection of growth and medication of COVID-19 affected people after 30 days of lock down in India

2020 ◽  
Author(s):  
Achintya Bhattacharyya ◽  
Debosmita Bhattacharyya ◽  
Joy Mukherjee
Keyword(s):  
Mathematical Model ◽  
Large Population ◽  
Simple Mathematical Model ◽  
Recovery Coefficient ◽  
Corona Virus ◽  
The People ◽  
The World ◽  
Different Types ◽  
Minimum Number

The COVID-19 pandemic has already consumed few months of indolence all over the world. Almost every part of the world from which the victim of COVID 19 are, have not yet been able to find out a strong way to combat corona virus. Therefore, the main aim is to minimize the spreading of the COVID-19 by detecting most of the affected people during lockdown. Hence, it is necessary to understand what the nature of growth is of spreading of this corona virus with time after almost one month (30 days) of lockdown. In this paper we have developed a very simple mathematical model to describe the growth of spreading of corona virus in human being. This model is based on realistic fact and the statistics we have so far. For controlling the spread of the COVID-19, minimization of the growth with minimum number of days of lockdown is necessary. We have established a relation between the long-term recovery coefficient and the long-term infected coefficient. The growth can be minimized if such condition satisfies. We have also discussed how the different age of the people can be cured by applying different types of medicine. We have presented the data of new cases, recovery and deaths per day to visualize the different coefficient for India and establish our theory. We have also explained how the medicine could be effective to sustain and improve such condition for country having large population like India.

scholarly journals New methodical approaches to justify selection explosive for destruction of solid rocks

2019 ◽  
Vol 109 ◽  
pp. 00032
Author(s):  
Kostiantyn Ishchenko ◽  
Svitlana Us ◽  
Oleksii Ishchenko ◽  
Dmytro Koba
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Systematic Approach ◽  
Complex Structure ◽  
Reasonable Approach ◽  
Social Environmental ◽  
Selection Of

The article developed a mathematical model to justify selection the type of explosive for destruction of solid rocks. The problem is solved using the analytical hierarchy method (AHM). In the process, many criteria, both quantitative and qualitative, were considered, their importance in selecting the type of explosives and their consistency with the opinions of experts. The following indicators were used as criteria: technological, economic, social, environmental, etc. According to the results, priority vectors were obtained for each hierarchy, which contributed to a reasonable approach to selection type of explosives. The established priorities made it possible to carry out a systematic approach to solve the problem, considering not only technological advantages, but also the costs of using various types of explosives. The factors characterizing the costs in the formation of well charges with various types of explosives are also considered. The results of mathematical modeling showed the adequacy of chosen model for selection of alternative types of explosives for the destruction of solid rocks of complex structure.

Thoughts on the Long-Term Strategy, Science and Democracy

2006 ◽  
pp. 4-19 ◽  
Author(s):  
L. Abalkin
Keyword(s):  
Strategy Development ◽  
Russian Science ◽  
Global Trends ◽  
The World ◽  
World Development ◽  
Crucial Condition

The article covers unified issues of the long-term strategy development, the role of science as well as democracy development in present-day Russia. The problems of budget proficit, the Stabilization Fund issues, implementation of the adopted national projects, an increasing role of regions in strengthening the integrity and prosperity of the country are analyzed. The author reveals that the protection of businessmen and citizens from the all-embracing power of bureaucrats is the crucial condition of democratization of the society. Global trends of the world development and expert functions of the Russian science are presented as well.

Coal's Persistence in the Capitalist World-Economy

2020 ◽  
Vol 6 (2) ◽  
pp. 194-221 ◽  
Author(s):  
Paul K. Gellert ◽  
Paul S. Ciccantell
Keyword(s):  
World Economy ◽  
Industrial Revolution ◽  
Energy Transition ◽  
Ecological Modernization ◽  
World Systems ◽  
Coal Consumption ◽  
The World ◽  
Capitalist World Economy ◽  
Capitalist World

Predominant analyses of energy offer insufficient theoretical and political-economic insight into the persistence of coal and other fossil fuels. The dominant narrative of coal powering the Industrial Revolution, and Great Britain's world dominance in the nineteenth century giving way to a U.S.- and oil-dominated twentieth century, is marred by teleological assumptions. The key assumption that a complete energy “transition” will occur leads some to conceive of a renewable-energy-dominated twenty-first century led by China. After critiquing the teleological assumptions of modernization, ecological modernization, energetics, and even world-systems analysis of energy “transition,” this paper offers a world-systems perspective on the “raw” materialism of coal. Examining the material characteristics of coal and the unequal structure of the world-economy, the paper uses long-term data from governmental and private sources to reveal the lack of transition as new sources of energy are added. The increases in coal consumption in China and India as they have ascended in the capitalist world-economy have more than offset the leveling-off and decline in some core nations. A true global peak and decline (let alone full substitution) in energy generally and coal specifically has never happened. The future need not repeat the past, but technical, policy, and movement approaches will not get far without addressing the structural imperatives of capitalist growth and the uneven power structures and processes of long-term change of the world-system.

Biomedical Materials to Repair Retinal Detachments

1985 ◽  
Vol 55 ◽  
Author(s):  
Miguel F. Refojo
Keyword(s):  
Retinal Detachment ◽  
Silicone Rubber ◽  
Methyl Acrylate ◽  
Silicone Oil ◽  
Vitreous Body ◽  
Light Sensitivity ◽  
Scleral Buckling ◽  
Intraocular Injection ◽  
Other Substances

ABSTRACTImplants are essential for the repair of retinal detachments. The implant buckles the wall of the eye and apposes the detached retina with the choroid, thus restoring light sensitivity to the retina. The scleral buckling also relieves traction on the retina from a shrinking vitreous body. The implant materials most commonly used are solid silicone rubber and silicone sponges, but both types have some disadvantages. A poly(hydroxyethyl acrylate-co-methyl acrylate) hydrogel implant with improved properties of softness and antibiotic absorption is also available for retinal detachment surgery. Proliferative vitreoretinopathy involves various conditions of retinal detachment complicated by vitreous fibrosis, which, after vitrectomy, may be treated with intraocular injection of fluids that support the retina against the choroid. For conditions requiring a long-term implant, silicone oil although controversial is the material of choice. Many other substances have been investigated but none better has yet been found.

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