Omnichannel and Experience Approach as a Post-COVID-19 Economic Reactivation Mechanism

The aim of this chapter is to show how omnichannel tools must be applied through the process of creating experiences for the consumers. During the literature review, some authors make approaches to the key concepts connecting omnichannels and consumer experiences; therefore, they explain through the analysis of data the reality of the Ecuadorian environment and global trends. With this context, this chapter will present how, by using macro environment and accessibility, a unique experience may be created in the customer journey in omnichannel.

Mechanism for the reactivation of the peroxidase activity of human cyclooxygenases: investigation using phenol as a reducing cosubstrate

It has been known for many years that the peroxidase activity of cyclooxygenase 1 and 2 (COX-1 and COX-2) can be reactivated in vitro by the presence of phenol, which serves as a reducing compound, but the underlying mechanism is still poorly understood. In the present study, we use phenol as a model compound to investigate the mechanism by which the peroxidase activity of human COXs is reactivated after each catalytic cycle. Molecular docking and quantum mechanics calculations are carried out to probe the interaction of phenol with the peroxidase site of COXs and the reactivation mechanism. It is found that the oxygen atom associated with the Fe ion in the heme group (i.e., the complex of Fe ion and porphyrin) of COXs can be removed by addition of two protons. Following its removal, phenol can readily bind inside the peroxidase active sites of the COX enzymes, and directly interact with Fe in heme to facilitate electron transfer from phenol to heme. This investigation provides theoretical evidence for several intermediates formed in the COX peroxidase reactivation cycle, thereby unveiling mechanistic details that would aid in future rational design of drugs that target the peroxidase site.

A practical fracability evaluation for tight sandstone reservoir with natural interface

Hydraulic fracturing has been widely applied to enhance the conductivity in tight sandstone reservoirs, i.e. reservoirs with low porosity and permeability. The interaction between a hydraulic fracture (HF) and a natural fracture (NF), including crossing, arresting and opening (tensile or dilation), are crucial for controlling the fracability of a reservoir. Previous studies have elucidated that shear dilation is the main mechanism for enhancing the permeability of an unconventional reservoir. Moreover, the brittleness index (BI) is considered another critical parameter that controls the fracability of candidates. However, the fracability of candidates with respect to both shear dilation and BI have not been fully investigated. We performed a practical fracability evaluation by integrating the shear dilation mechanism and BI quantification. We obtained the mechanical parameters from mechanical tests conducted on synthetic tight sandstone samples, and we manufactured specimens with different friction coefficients and shear strengths. Next, we performed scaled hydraulic fracturing experiments on 15 identical 10 cm cubic samples using a true tri-axial stress cell, and the interaction mechanisms between HFs and NFs were investigated. We also evaluated the brittleness of each specimen based on a previous BI model and our own novel BI model. We found that a weak interface cohesion with an interaction (between HF and NF) angle of 60° exhibited a shear dilation (or reactivation) mechanism and a higher BI. We thus conclude that such conditions are more favourable for reservoir stimulation (i.e. hydraulic fracturing) in the field.

Structure of a prereaction complex between the nerve agent sarin, its biological target acetylcholinesterase, and the antidote HI-6

Organophosphorus nerve agents interfere with cholinergic signaling by covalently binding to the active site of the enzyme acetylcholinesterase (AChE). This inhibition causes an accumulation of the neurotransmitter acetylcholine, potentially leading to overstimulation of the nervous system and death. Current treatments include the use of antidotes that promote the release of functional AChE by an unknown reactivation mechanism. We have used diffusion trap cryocrystallography and density functional theory (DFT) calculations to determine and analyze prereaction conformers of the nerve agent antidote HI-6 in complex with Mus musculus AChE covalently inhibited by the nerve agent sarin. These analyses reveal previously unknown conformations of the system and suggest that the cleavage of the covalent enzyme–sarin bond is preceded by a conformational change in the sarin adduct itself. Together with data from the reactivation kinetics, this alternate conformation suggests a key interaction between Glu202 and the O-isopropyl moiety of sarin. Moreover, solvent kinetic isotope effect experiments using deuterium oxide reveal that the reactivation mechanism features an isotope-sensitive step. These findings provide insights into the reactivation mechanism and provide a starting point for the development of improved antidotes. The work also illustrates how DFT calculations can guide the interpretation, analysis, and validation of crystallographic data for challenging reactive systems with complex conformational dynamics.