Quasi-two-dimensional NaCl crystals encapsulated between graphene sheets and their decomposition under an electron beam.

Quasi-two-dimensional (2D) sodium chloride (NaCl) crystals of various lateral sizes between graphene sheets were manufactured supersaturation from a saline solution. Aberration-corrected transmission electron microscopy was used for systematic investigations of the crystals and their decomposition under an 80 kV electron beam. Counterintuitively, bigger clusters were found to disintegrate faster under electron irradiation, but in general no correlation between crystal sizes and electron doses at which the crystals decompose was found.

The Effect of Face Mask Use on COVID-19 Models.

We begin with a simple model for the COVID-19 epidemic and add face mask usages and testing and quarantine of infectives. We estimate the effect on the reproduction number and discuss the question of whether the epidemic can be controlled by increased use of face masks.

A co-interaction model of HIV and syphilis infection among gay, bisexual and other men who have sex with men.

We developed a mathematical model to study the co-interaction of HIV and syphilis infection among gay, bisexual and other men who have sex with men (gbMSM). We qualitatively analysed the model and established necessary conditions under which disease-free and endemic equilibria are asymptotically stable. We gave analytical expressions for the reproduction number, and showed that whenever the reproduction numbers of sub-models and co-interaction model are less than unity, the epidemics die out, while epidemics persist when they are greater than unity.

A novel approach to modelling the spatial spread of airborne diseases: an epidemic model with indirect transmission.

We formulated and analyzed a class of coupled partial and ordinary differential equation (PDE-ODE) model to study the spread of airborne diseases. Our model describes human populations with patches and the movement of pathogens in the air with linear diffusion. The diffusing pathogens are coupled to the SIR dynamics of each population patch using an integro-differential equation.

Modelling and simulating Chikungunya spread with an unstructured triangular cellular automata.

In this work we propose a mathematical model to simulate Chikungunya spread; the spread model is implemented in a C++ cellular automata code defined on unstructured triangular grids and space visualizations are performed with Python. In order to simulate the time space spread of the Chikungunya diseases we include assumptions such as: heterogeneous human and vector densities, population mobility, geographically localized points of infection using geographical information systems, changes in the probabilities of infection, extrinsic incubation and mosquito death rate due to environmental variables. Numerical experiments reproduce the qualitative behavior of diseases spread and provide an insight to develop strategies to prevent the diseases spread.