A computational approach to model gliding motion of an organism on a sticky slime layer over a solid substrate

Bacteria are microscopic single-celled microbes that can only be spotted via a microscope. They occur in a variety of shapes and sizes, and their dimensions are measured in micrometers (one-millionth of a meter). Bacterial categorization is based on a variety of features such as morphology, DNA sequencing, presence of flagella, cell structure, staining techniques, oxygen, and carbon-dioxide requirements. Due to these classifications, gliding bacteria are a miscellaneous class of rodlike microorganisms that cling and propel over ooze slime connected with a substrate. Without the assistance of flagella, which are essential parts of bacterial motility, the organism movement is adopted by waves streaming down the outer layer of this microorganism. To simulate the locomotion of such gliding microorganisms, a wavy sheet over Oldroyd-4 constant fluid is utilized. Under the long wavelength assumption, the equations regulating the flow of slime (modeled as Oldroyd-4 constant slime) beneath the cell/organism are developed. The quantities such as slime flow rate, cell speed, and propulsion power are computed by using bvp4c (MATLAB routine) integrated with the modified Newton-Rasphson technique. Furthermore, the flow patterns and velocity of the slime are graphically shown and thoroughly described using precise (calculated) values of the cell speed and velocity of the slime.

A bioconvection model for viscoelastic nanofluid confined by tapered asymmetric channel: implicit finite difference simulations

As part of the growing evolution in nanotechnology and thermal sciences, nanoparticles are considered as an alternative solution for the energy depletion due to their ultra-high thermal effectives. Nanofluids reflect inclusive and broad-spectrum significances in engineering, industrial and bio-engineering like power plants, energy source, air conditioning systems, surface coatings, evaporators, power consumptions, nano-medicine, cancer treatment, etc. The present study describes the bio-convective peristaltic flow of a third-grade nanofluid in a tapered asymmetric channel. Basic conservation laws of mass, momentum, energy, and concentration as well as the microorganism diffusion equation are utilized to model the problem. The simplified form of the modeled expressions is accounted with long wavelength assumptions. For solving the resulting coupled and nonlinear equations, a well-known numerical method implicit finite difference scheme has been utilized. The graphical results describe the velocity, temperature and concentration profiles, and the density of motile microorganisms at the nanoscale. Furthermore, microorganism concentration lines are analyzed.

Silica Mesoporous Structures: Effective Nanocarriers in Drug Delivery and Nanocatalysts

The application of silica mesoporous structures in drug delivery and the removal of pollutants and organic compounds through catalytic reactions is increasing due to their unique characteristics, including high loading capacities, tunable pores, large surface areas, sustainability, and so on. This review focuses on very well-studied class of different construction mesoporous silica nano(particles), such as MCM-41, SBA-15, and SBA-16. We discuss the essential parameters involved in the synthesis of these materials with providing a diverse set of examples. In addition, the recent advances in silica mesoporous structures for drug delivery and catalytic applications are presented to fill the existing gap in the literature with providing some promising examples on this topic for the scientists in both industry and academia active in the field. Regarding the catalytic applications, mesoporous silica particles have shown some promises to remove the organic pollutants and to synthesize final products with high yields due to the ease with which their surfaces can be modified with various ligands to create appropriate interactions with target molecules. In the drug delivery process, as nanocarriers, they have also shown very good performance thanks to the easy surface functionalization but also adjustability of their porosities to providing in-vivo and in-vitro cargo delivery at the target site with appropriate rate.