Uncontrolled cell proliferation is one of the key features leading to cancer. Seminal works in chronobiology have revealed that disruption of the circadian timing system in mice, either by surgical, ...genetic, or environmental manipulation, increased tumor development. In humans, shift work is a risk factor for cancer. Based on these observations, the link between the circadian clock and cell cycle has become intuitive. But despite identification of molecular connections between the two processes, the influence of the clock on the dynamics of the cell cycle has never been formally observed. Recently, two studies combining single live cell imaging with computational methods have shed light on robust coupling between clock and cell cycle oscillators. We recapitulate here these novel findings and integrate them with earlier results in both healthy and cancerous cells. Moreover, we propose that the cell cycle may be synchronized or slowed down through coupling with the circadian clock, which results in reduced tumor growth. More than ever, systems biology has become instrumental to understand the dynamic interaction between the circadian clock and cell cycle, which is critical in cellular coordination and for diseases such as cancer.
Excelet for Simulation of Indium DSC Graph Catangiu, Adrian; Ungureanu, Dan Nicolae; Nicolescu, Cristina ...
The Scientific Bulletin of "Valahia" University, Materials and Mechanics,
10/2023, Volume:
19, Issue:
21
Journal Article
Peer reviewed
Open access
Spreadsheets have amazing facilities for graphical representation of data. The computing power and the possibility to get the results without programming, interactivity by using controls make ...spreadsheets a powerful learning tool. Having as starting point an DSC curve for Indium performed between 120°C and 180°C, the shape of curve was modeled, by using Excel, under assumption that, before and after peak corresponding to melting transition, there is no dependence between specific heat of metal and temperature. Even the peak shape it not perfect symmetrical, it was modeled considering a gaussian distribution. Linear regression has been used for computing the medium values of specific heat in solid and liquid state and was used a spinner as interactive tool for peak shape control. Despite the model deficiencies, starting from specific heats, latent heat of melting and peak apex temperature it has been possible the simulation of DSC curve which was in a good correlation with the real one.
COVID-19 pandemic has underlined the impact of emergent pathogens as a major threat to human health. The development of quantitative approaches to advance comprehension of the current outbreak is ...urgently needed to tackle this severe disease.
Considering different starting times of infection, mathematical models are proposed to represent SARS-CoV-2 dynamics in infected patients. Based on the target cell limited model, the within-host reproductive number for SARS-CoV-2 is consistent with the broad values of human influenza infection. The best model to fit the data was including immune cell response, which suggests a slow immune response peaking between 5 to 10 days post-onset of symptoms. The model with the eclipse phase, time in a latent phase before becoming productively infected cells, was not supported. Interestingly, model simulations predict that SARS-CoV-2 may replicate very slowly in the first days after infection, and viral load could be below detection levels during the first 4 days post infection.
A quantitative comprehension of SARS-CoV-2 dynamics and the estimation of standard parameters of viral infections is the key contribution of this pioneering work. These models can serve for future evaluation of control theoretical approaches to tailor new drugs against COVID-19.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper analyses numerical efforts regarding nanosecond (NS) surface dielectric barrier discharge (SDBD) modelling in atmospheric air. Numerical results of the discharge structure for positive and ...negative applied voltage pulse polarity, and the features of the physical models and boundary conditions used, are discussed. The results of 2D simulations of the quasi-uniform SDBD mode are presented and compared with the results of other research teams, and with experimental data, to reveal the most appropriate approaches. New results of numerical simulations and analytical estimations of the energy into gas deposition due to NS SDBD driven by a single NS voltage pulse are presented. The problems relating to NS SDBD modelling are discussed.
The World Health Organization on 11 March 2020, declared COVID-19 as a pandemic. India initiated social distancing measures to combat the epidemic of COVID-19. The course of the epidemic of COVID-19 ...for India was predicted using stochastic probability–based mathematical modeling.
Data synthesis for the top few countries affected was studied for various factors affecting the epidemic. For projections of infected cases for India, the modified susceptible-exposed-infectious-removed/recovered framework modified for the effect of social distancing (Rho) was used. Simulation was carried out for 10,000 runs using Python. Projections for infected cases and hospitalization requirement were estimated.
The epidemic curve will peak in the third week of June in India with 17,525,869 and 2,153,200 infected people with reproduction number of 1.8 and Rho of 0.7 and 0.6, respectively. Compared with the baseline scenario of no social distancing, for transmissibility with R0 = 1.8, the reduction in infections due to social distancing measure is 78% (Rho = 0.7) and 97% (Rho = 0.6). Similarly for R0 = 2.2 and 2.4, the reduction in infected numbers slightly lowers to 62% and 66% with Rho = 0.7 and 92% and 75% with Rho = 0.6, respectively. With R0 = 1.8 and Rho = 0.6, the Intensive Care Unit (ICU) bed requirement is 107,660, whereas if transmissibility is high, the ICU bed requirement would increase to 1,994,682.
The social distancing measures seem to have been working for India in absence of treatment in sight for COVID-19. Although with the government's response strategy of social distancing, the peak of the epidemic is extended giving more months for preparedness to the country; however, the sustainability of these measures is uncertain.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Uncertainties in the relative biological effectiveness (RBE) of protons remains a major barrier to the biological optimisation of proton therapy. While a constant value of 1.1 is widely used in ...treatment planning, extensive preclinical in vitro and in vivo data suggests that proton RBE is variable, depending on proton energy, target tissue, and endpoint. A number of phenomenological models have been developed to try and explain this variation, but agreement between these models is often poor. This has been attributed to both the models' underlying assumptions and the data to which they are fit. In this brief note, we investigate the underlying trends in these models by comparing their predictions as a function of relevant biological and physical parameters, to determine where models are in conceptual agreement or disagreement. By doing this, it can be seen that the primary differences between models arise from how they handle biological parameters (i.e. Formula: see text and Formula: see text from the linear-quadratic model for photon exposures). By contrast, when specifically explored for linear energy transfer-dependence, all models show extremely good correlation. These observations suggest that there is a pressing need for more systematic exploration of biological variation in RBE across different cells in well-controlled conditions to help distinguish between these different models and identify the true behaviour.
This work aims to apply the SIR-type compartmental model (Susceptible - Infected - Removed) in the evolution of Covid-19 in Paraíba's State and Campina Grande City. For that, the parameters of the ...model were considered to be variable during time evolution, within an appropriate range. The system of differential equations was solved numerically using the Euler method. The parameters were obtained by adjusting the model to the infected data provided by the Paraíba Health Department. According to the results obtained, the model describes the infected population well. There was a reduction in the effective reproduction number in Paraíba and the town of Campina Grande. It is noteworthy that understanding the dynamics of infection transmission and evaluating the effectiveness of control measures is crucial to assess the potential for sustained transmission to occur in new areas. The model can also be applied to describe epidemic dynamics in other regions and countries.
The new coronavirus has spread around the world at an unprecedented speed. Understanding patterns of disease spread is an important contribution to controlling any epidemic, and today’s mathematical ...methods offer a plethora of proven models to choose from. We provide a brief overview of epidemiological concepts, papers pertaining to mathematical modelling, and present a robust, simple mathematical model to model incidence of COVID-19 cases in Croatia during the first year of the disease. For our models, we chose logistic, Gumbel and Richards functions, with parameters generated using the Levenberg-Marquardt iterative method of nonlinear regression. In conclusion, all three models provided adequate estimation of incidence curve and final number of infected during the chosen time period, with relatively minor differences depending on chosen parameters of significance. The model using the logistic function proved to be the most applicable to available data. While no model can give the answers to ending the pandemic, this approach can provide a simple prognostic tool to evaluate interventions and estimate disease spread.
In vivo experiments on broilers were conducted in order to elaborate a mathematical model for body synthesis, the experimental data being processed with Gompertz time functions and linear functions. ...The experiment used 166, Ross 308 day-old chicks through an experimental period of 42 days. The broilers received diets according to the growth period (1 – 14, 15 – 28, 29 – 42 days). The dietary energy and nutrient supply for group 1 (control) were according to the recommendation of Ross Breeders. The birds had free access to the feed. Group 2 received 90% and group 3 received 80% of the amount of feed received by group 1; the dietary energy supply was 90% in group 4 and 80% in group 5, also related to group 1. Mathematical modelling was used to evaluate the evolution of the body chemical composition (water, protein and lipid content), starting from the protein content at hatching.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The students who study biology often develop fear from mathematical concepts and tend to avoid the pages of biology textbook where mathematical details are included. The students often perceive ...Mathematics and Biology as two separate disciplines of study. One of the main reasons for this perception is that biology textbooks do not include relevant mathematical details in biological concepts. Moreover, biology teachers often have little or no mathematical academic background while mathematics is taught by teachers with least or no interest in biology. This often leads to the lack of understanding among students that both subjects are actually linked to each other. So, the students study them in parallel and there are hardly any cross talks between these two subjects. But, the myth is debunked later when biology students reach the undergraduate and postgraduate level wherein they are expected to apply the mathematical skills to understand the biological concepts. So, if the realization is sparked at an early stage during schooling years that both Mathematics and Biology are related to each other, then the ‘Maths phobia’ among Biology students can be easily overcome. In this article, illustrative examples have been presented with detailed explanation wherein the biology students can appreciate mathematical concepts efficiently in a teaching-learning environment at the senior secondary level.
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