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Artikel ; Online: Analysis of Delayed Vaccination Regimens

Gilberto Gonzalez-Parra

Epidemiologia, Vol 2, Iss 21, Pp 271-

A Mathematical Modeling Approach

2021 Band 293

Abstract: The first round of vaccination against coronavirus disease 2019 (COVID-19) began in early December of 2020 in a few countries. There are several vaccines, and each has a different efficacy and mechanism of action. Several countries, for example, the ... ...

Abstract	The first round of vaccination against coronavirus disease 2019 (COVID-19) began in early December of 2020 in a few countries. There are several vaccines, and each has a different efficacy and mechanism of action. Several countries, for example, the United Kingdom and the USA, have been able to develop consistent vaccination programs where a great percentage of the population has been vaccinated (May 2021). However, in other countries, a low percentage of the population has been vaccinated due to constraints related to vaccine supply and distribution capacity. Countries such as the USA and the UK have implemented different vaccination strategies, and some scholars have been debating the optimal strategy for vaccine campaigns. This problem is complex due to the great number of variables that affect the relevant outcomes. In this article, we study the impact of different vaccination regimens on main health outcomes such as deaths, hospitalizations, and the number of infected. We develop a mathematical model of COVID-19 transmission to focus on this important health policy issue. Thus, we are able to identify the optimal strategy regarding vaccination campaigns. We find that for vaccines with high efficacy (>70%) after the first dose, the optimal strategy is to delay inoculation with the second dose. On the other hand, for a low first dose vaccine efficacy, it is better to use the standard vaccination regimen of 4 weeks between doses. Thus, under the delayed second dose option, a campaign focus on generating a certain immunity in as great a number of people as fast as possible is preferable to having an almost perfect immunity in fewer people first. Therefore, based on these results, we suggest that the UK implemented a better vaccination campaign than that in the USA with regard to time between doses. The results presented here provide scientific guidelines for other countries where vaccination campaigns are just starting, or the percentage of vaccinated people is small.
Schlagwörter	SARS-CoV-2 virus ; vaccination ; delayed dose ; mathematical modeling ; simulation ; Internal medicine ; RC31-1245
Sprache	Englisch
Erscheinungsdatum	2021-07-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Retraction

Gilberto Gonzalez / Lizhen Chen

Cells, Vol 11, Iss 1721, p

Gonzalez, G.; Chen, L. EFA6 in Axon Regeneration, as a Microtubule Regulator and as a Guanine Nucleotide Exchange Factor. Cells 2021, 10 , 1325

2022 Band 1721

Abstract: The journal retracts the article “Retraction: Gonzalez, G.; Chen, L. EFA6 in Axon Regeneration, as a Microtubule Regulator and as a Guanine Nucleotide Exchange Factor” [.] ...

Abstract	The journal retracts the article “Retraction: Gonzalez, G.; Chen, L. EFA6 in Axon Regeneration, as a Microtubule Regulator and as a Guanine Nucleotide Exchange Factor” [.]
Schlagwörter	n/a ; Biology (General) ; QH301-705.5
Sprache	Englisch
Erscheinungsdatum	2022-05-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: EFA6 in Axon Regeneration, as a Microtubule Regulator and as a Guanine Nucleotide Exchange Factor

Gilberto Gonzalez / Lizhen Chen

Cells, Vol 10, Iss 1325, p

2021 Band 1325

Abstract: Axon regeneration after injury is a conserved biological process that involves a large number of molecular pathways, including rapid calcium influx at injury sites, retrograde injury signaling, epigenetic transition, transcriptional reprogramming, ... ...

Abstract	Axon regeneration after injury is a conserved biological process that involves a large number of molecular pathways, including rapid calcium influx at injury sites, retrograde injury signaling, epigenetic transition, transcriptional reprogramming, polarized transport, and cytoskeleton reorganization. Despite the numerous efforts devoted to understanding the underlying cellular and molecular mechanisms of axon regeneration, the search continues for effective target molecules for improving axon regeneration. Although there have been significant historical efforts towards characterizing pro-regenerative factors involved in axon regeneration, the pursuit of intrinsic inhibitors is relatively recent. EFA6 (exchange factor for ARF6) has been demonstrated to inhibit axon regeneration in different organisms. EFA6 inhibition could be a promising therapeutic strategy to promote axon regeneration and functional recovery after axon injury. This review summarizes the inhibitory role on axon regeneration through regulating microtubule dynamics and through affecting ARF6 (ADP-ribosylation factor 6) GTPase-mediated integrin transport.
Schlagwörter	EFA6 ; axon injury ; axon regeneration ; microtubule dynamics ; integrin ; ARF6 ; Biology (General) ; QH301-705.5
Thema/Rubrik (Code)	306
Sprache	Englisch
Erscheinungsdatum	2021-05-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Impact of a New SARS-CoV-2 Variant on the Population

Gilberto Gonzalez-Parra / David Martínez-Rodríguez / Rafael J. Villanueva-Micó

Mathematical and Computational Applications, Vol 26, Iss 25, p

A Mathematical Modeling Approach

2021 Band 25

Abstract: Several SARS-CoV-2 variants have emerged around the world, and the appearance of other variants depends on many factors. These new variants might have different characteristics that can affect the transmissibility and death rate. The administration of ... ...

Abstract	Several SARS-CoV-2 variants have emerged around the world, and the appearance of other variants depends on many factors. These new variants might have different characteristics that can affect the transmissibility and death rate. The administration of vaccines against the coronavirus disease 2019 (COVID-19) started in early December of 2020 and in some countries the vaccines will not soon be widely available. For this article, we studied the impact of a new more transmissible SARS-CoV-2 strain on prevalence, hospitalizations, and deaths related to the SARS-CoV-2 virus. We studied different scenarios regarding the transmissibility in order to provide a scientific support for public health policies and bring awareness of potential future situations related to the COVID-19 pandemic. We constructed a compartmental mathematical model based on differential equations to study these different scenarios. In this way, we are able to understand how a new, more infectious strain of the virus can impact the dynamics of the COVID-19 pandemic. We studied several metrics related to the possible outcomes of the COVID-19 pandemic in order to assess the impact of a higher transmissibility of a new SARS-CoV-2 strain on these metrics. We found that, even if the new variant has the same death rate, its high transmissibility can increase the number of infected people, those hospitalized, and deaths. The simulation results show that health institutions need to focus on increasing non-pharmaceutical interventions and the pace of vaccine inoculation since a new variant with higher transmissibility, such as, for example, VOC-202012/01 of lineage B.1.1.7, may cause more devastating outcomes in the population.
Schlagwörter	SARS-CoV-2 variant ; mutation ; scenarios ; mathematical modeling ; simulation ; Applied mathematics. Quantitative methods ; T57-57.97 ; Mathematics ; QA1-939 ; Electronic computers. Computer science ; QA75.5-76.95
Sprache	Englisch
Erscheinungsdatum	2021-03-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Analysis of Key Factors of a SARS-CoV-2 Vaccination Program

David Martínez-Rodríguez / Gilberto Gonzalez-Parra / Rafael-J. Villanueva

Epidemiologia, Vol 2, Iss 12, Pp 140-

A Mathematical Modeling Approach

2021 Band 161

Abstract: The administration of vaccines against the coronavirus disease 2019 (COVID-19) started in early December of 2020. Currently, there are only a few approved vaccines, each with different efficacies and mechanisms of action. Moreover, vaccination programs ... ...

Abstract	The administration of vaccines against the coronavirus disease 2019 (COVID-19) started in early December of 2020. Currently, there are only a few approved vaccines, each with different efficacies and mechanisms of action. Moreover, vaccination programs in different regions may vary due to differences in implementation, for instance, simply the availability of the vaccine. In this article, we study the impact of the pace of vaccination and the intrinsic efficacy of the vaccine on prevalence, hospitalizations, and deaths related to the SARS-CoV-2 virus. Then we study different potential scenarios regarding the burden of the COVID-19 pandemic in the near future. We construct a compartmental mathematical model and use computational methodologies to study these different scenarios. Thus, we are able to identify some key factors to reach the aims of the vaccination programs. We use some metrics related to the outcomes of the COVID-19 pandemic in order to assess the impact of the efficacy of the vaccine and the pace of the vaccine inoculation. We found that both factors have a high impact on the outcomes. However, the rate of vaccine administration has a higher impact in reducing the burden of the COVID-19 pandemic. This result shows that health institutions need to focus on increasing the vaccine inoculation pace and create awareness in the population about the importance of COVID-19 vaccines.
Schlagwörter	SARS-CoV-2 virus ; vaccination ; mathematical modeling ; simulation ; Internal medicine ; RC31-1245
Sprache	Englisch
Erscheinungsdatum	2021-04-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Impact of Infective Immigrants on COVID-19 Dynamics

Stéphane Yanick Tchoumi / Herieth Rwezaura / Mamadou Lamine Diagne / Gilberto González-Parra / Jean Tchuenche

Mathematical and Computational Applications, Vol 27, Iss 11, p

2022 Band 11

Abstract: The COVID-19 epidemic is an unprecedented and major social and economic challenge worldwide due to the various restrictions. Inflow of infective immigrants have not been given prominence in several mathematical and epidemiological models. To investigate ... ...

Abstract	The COVID-19 epidemic is an unprecedented and major social and economic challenge worldwide due to the various restrictions. Inflow of infective immigrants have not been given prominence in several mathematical and epidemiological models. To investigate the impact of imported infection on the number of deaths, cumulative infected and cumulative asymptomatic, we formulate a mathematical model with infective immigrants and considering vaccination. The basic reproduction number of the special case of the model without immigration of infective people is derived. We varied two key factors that affect the transmission of COVID-19, namely the immigration and vaccination rates. In addition, we considered two different SARS-CoV-2 transmissibilities in order to account for new more contagious variants such as Omicron. Numerical simulations using initial conditions approximating the situation in the US when the vaccination program was starting show that increasing the vaccination rate significantly improves the outcomes regarding the number of deaths, cumulative infected and cumulative asymptomatic. Other factors are the natural recovery rates of infected and asymptomatic individuals, the waning rate of the vaccine and the vaccination rate. When the immigration rate is increased significantly, the number of deaths, cumulative infected and cumulative asymptomatic increase. Consequently, accounting for the level of inflow of infective immigrants may help health policy/decision-makers to formulate policies for public health prevention programs, especially with respect to the implementation of the stringent preventive lock down measure.
Schlagwörter	COVID-19 ; infected immigrants ; vaccination ; basic reproduction number ; Applied mathematics. Quantitative methods ; T57-57.97 ; Mathematics ; QA1-939 ; Electronic computers. Computer science ; QA75.5-76.95
Sprache	Englisch
Erscheinungsdatum	2022-01-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Mathematical Modeling of Physical Capital Diffusion Using a Spatial Solow Model

Gilberto González-Parra / Benito Chen-Charpentier / Abraham J. Arenas / Miguel Díaz-Rodríguez

Economies, Vol 10, Iss 164, p

Application to Smuggling in Venezuela

2022 Band 164

Abstract: This study proposes a mathematical modeling approach for the physical capital diffusion through the borders of countries. Physical capital is considered a crucial variable for the economic growth of a nation. Here, we use an extension of the economic ... ...

Abstract	This study proposes a mathematical modeling approach for the physical capital diffusion through the borders of countries. Physical capital is considered a crucial variable for the economic growth of a nation. Here, we use an extension of the economic Solow model to describe how smuggling affects the economic growth of countries. In particular, we focus on the situation in Venezuela from 2012 to 2015. In this regard, we rely on a nonconcave production function instead of the classical Cobb–Douglas production function. Moreover, we investigate the effect of different physical capital fluxes on economic growth. The physical capital diffusion through the borders of a country is modeled based on a parabolic partial differential equation describing the dynamics of physical capital and boundary conditions of the Neumann type. Smuggling is present at numerous borders between countries and may include fuel, machinery, and food. This smuggling through the borders places challenges on a particular country’s economy. The smuggling problem usually is related to a non-official exchange rate different from the official rate or subsidies. We study the effect of smuggling on the physical capital of a country using an extended Solow model. Numerical simulations are obtained using an explicit finite difference scheme describing how the physical capital diffusion through the border of a country affects its economic growth. The study of physical capital is a paramount aspect of the economic growth of several countries. The results show that when boundary conditions of Neumann type are different from zero, the dynamics of the physical capital differ from the classical economic behavior observed in the classical spatial Solow model without physical capital flux through the borders of countries. In particular, the numerical results show that the physical capital of a country decreases faster as the flux increases on the boundaries. Thus, we can conclude that avoiding smuggling through the frontiers is a crucial factor affecting ...
Schlagwörter	Solow model ; mathematical modeling ; physical capital ; numerical simulation ; Neumann boundary conditions ; Economics as a science ; HB71-74
Thema/Rubrik (Code)	339
Sprache	Englisch
Erscheinungsdatum	2022-07-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: An East Coast Perspective on Artificial Intelligence and Machine Learning: Part 1: Hemorrhagic Stroke Imaging and Triage.

Gupta, Rajiv / Krishnam, Sanjith Prahas / Schaefer, Pamela W / Lev, Michael H / Gilberto Gonzalez, R

Neuroimaging clinics of North America

2020 Band 30, Heft 4, Seite(n) 459–466

Abstract: Hemorrhagic stroke is a medical emergency. Artificial intelligence techniques and algorithms may be used to automatically detect and quantitate intracranial hemorrhage in a semiautomated fashion. This article reviews the use of deep learning ... ...

Abstract	Hemorrhagic stroke is a medical emergency. Artificial intelligence techniques and algorithms may be used to automatically detect and quantitate intracranial hemorrhage in a semiautomated fashion. This article reviews the use of deep learning convolutional neural networks for managing hemorrhagic stroke. Such a capability may be used to alert appropriate care teams, make decisions about patient transport from a primary care center to a comprehensive stroke center, and assist in treatment selection. This article reviews artificial intelligence algorithms for intracranial hemorrhage detection, quantification, and prognostication. Multiple algorithms currently being explored are described and illustrated with the help of examples.
Mesh-Begriff(e)	Artificial Intelligence ; Brain/diagnostic imaging ; Diagnostic Imaging/methods ; Hemorrhagic Stroke/diagnostic imaging ; Humans ; Image Interpretation, Computer-Assisted/methods ; Machine Learning ; Neuroimaging/methods ; Triage/methods ; United States
Sprache	Englisch
Erscheinungsdatum	2020-09-17
Erscheinungsland	United States
Dokumenttyp	Journal Article ; Review
ZDB-ID	1314594-0
ISSN	1557-9867 ; 1052-5149
ISSN (online)	1557-9867
ISSN	1052-5149
DOI	10.1016/j.nic.2020.07.005
Datenquelle	MEDical Literature Analysis and Retrieval System OnLINE

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Artikel ; Online: Effect of stochasticity on coinfection dynamics of respiratory viruses

Lubna Pinky / Gilberto Gonzalez-Parra / Hana M. Dobrovolny

BMC Bioinformatics, Vol 20, Iss 1, Pp 1-

2019 Band 12

Abstract: Abstract Background Respiratory viral infections are a leading cause of mortality worldwide. As many as 40% of patients hospitalized with influenza-like illness are reported to be infected with more than one type of virus. However, it is not clear ... ...

Abstract	Abstract Background Respiratory viral infections are a leading cause of mortality worldwide. As many as 40% of patients hospitalized with influenza-like illness are reported to be infected with more than one type of virus. However, it is not clear whether these infections are more severe than single viral infections. Mathematical models can be used to help us understand the dynamics of respiratory viral coinfections and their impact on the severity of the illness. Most models of viral infections use ordinary differential equations (ODE) that reproduce the average behavior of the infection, however, they might be inaccurate in predicting certain events because of the stochastic nature of viral replication cycle. Stochastic simulations of single virus infections have shown that there is an extinction probability that depends on the size of the initial viral inoculum and parameters that describe virus-cell interactions. Thus the coinfection dynamics predicted by the ODE might be difficult to observe in reality. Results In this work, a continuous-time Markov chain (CTMC) model is formulated to investigate probabilistic outcomes of coinfections. This CTMC model is based on our previous coinfection model, expressed in terms of a system of ordinary differential equations. Using the Gillespie method for stochastic simulation, we examine whether stochastic effects early in the infection can alter which virus dominates the infection. Conclusions We derive extinction probabilities for each virus individually as well as for the infection as a whole. We find that unlike the prediction of the ODE model, for similar initial growth rates stochasticity allows for a slower growing virus to out-compete a faster growing virus.
Schlagwörter	Viral coinfection ; Respiratory virus ; Within-host model ; Continuous-time Markov chain ; Multi-type branching process ; Extinction probability ; Computer applications to medicine. Medical informatics ; R858-859.7 ; Biology (General) ; QH301-705.5
Thema/Rubrik (Code)	519
Sprache	Englisch
Erscheinungsdatum	2019-04-01T00:00:00Z
Verlag	BMC
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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Artikel ; Online: Optimization of the Controls against the Spread of Zika Virus in Populations

Gilberto González-Parra / Miguel Díaz-Rodríguez / Abraham J. Arenas

Computation, Vol 8, Iss 76, p

2020 Band 76

Abstract: In this paper, we study and explore two control strategies to decrease the spread of Zika virus in the human and mosquito populations. The control strategies that we consider in this study are awareness and spraying campaigns. We solve several optimal ... ...

Abstract	In this paper, we study and explore two control strategies to decrease the spread of Zika virus in the human and mosquito populations. The control strategies that we consider in this study are awareness and spraying campaigns. We solve several optimal control problems relying on a mathematical epidemic model of Zika that considers both human and mosquito populations. The first control strategy is broad and includes using information campaigns, encouraging people to use bednetting, wear long-sleeve shirts, or similar protection actions. The second control is more specific and relies on spraying insecticides. The control system relies on a Zika mathematical model with control functions. To develop the optimal control problem, we use Pontryagins’ maximum principle, which is numerically solved as a boundary value problem. For the mathematical model of the Zika epidemic, we use parameter values extracted from real data from an outbreak in Colombia. We study the effect of the costs related to the controls and infected populations. These costs are important in real life since they can change the outcomes and recommendations for health authorities dramatically. Finally, we explore different options regarding which control measures are more cost-efficient for society.
Schlagwörter	Zika virus ; optimal control dynamical systems ; Pontryagins’ maximum principle ; epidemiological models ; Electronic computers. Computer science ; QA75.5-76.95
Thema/Rubrik (Code)	510
Sprache	Englisch
Erscheinungsdatum	2020-08-01T00:00:00Z
Verlag	MDPI AG
Dokumenttyp	Artikel ; Online
Datenquelle	BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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