The Standing Acoustic Wave Principle within the Frequency Analysis of Acoustic Signals in the Cochlea

The frequency analysis of auditory perceptions takes place in the cochlea of the inner ear. The cochlea’s task is to transform the entrance vibrations of the oval window into individual frequency components of the acoustic signal entering the outer ear. This frequency analysis is provided by a coupling between the overall acoustic wave in the perilymph and the vibrations of the basilar membrane. 

With regard to the analyzed transformation of signals, the scala vestibuli, scale tympani, basilar membrane and organ of Corti are of the highest importance, the latter of which transforms deformations of the basilar membrane into tension pulses that are further conveyed to the relevant part of the brain. The cavities of the scala vestibuli and scale tympani are filled with the same liquid-perilymph. They are interconnected with a narrow opening called the helicotrema.

Understanding Dive Computers

Modern digital dive computers date to the early 80s, though analog devices simulating tissue gas uptake and elimination through porous membranes date back to the 70s. Analog devices were limited to nonstop diving and had a short shelf life. 

Digital dive computers proved highly successful and very useful right from the start, progressing from just table emulators to full up algorithmic staging devices across mixed gas, open circuit (OC), re breather (RB), nonstop, decompression, deep, and shallow diving. Dive computers are moderately expensive items these days, and high end units range beyond $1500. Basically, a decompression computer is a microprocessor consisting of a power source, pressure transducer, analog to digital signal converter, internal clock, chip with RAM (random access memory) and ROM (read only memory), and pixel display screen.

A Multi-Layer Non-Newtonian Model of Cardiovascular Inflammation

We found that such locations are correlated to the vulnerable plaque phenotype, which is prone to rupture. Our results demonstrate that at locations of high particle concentration, blood particles change the shear stress distribution and magnitude. Therefore, the non-Newtonian blood flow assumption provides new insights in the characterization of plaque built up. 

These results are combined to in-vitro experiments that suggest the influence of blood particles in the activity of cytokines. An unbalance in pro and anti-inflammatory cytokines has been associated to an increase in inflammation and, consequently, in the volume of plaques forming. We anticipate our work to be a starting point for a more sophisticated multi-scale model, which combines experimental findings and computational modelling to characterize arterial segments affected by atherosclerosis. Such model includes a coupling between the distending arterial wall and the non-Newtonian blood flow.

Human-Organoid Models: Accomplishments to Salvage Test-Animals

Late stage attritions in drug discovery are costly and consuming. Improbable response of test molecules acquired in non-human systems is attributed to be the major cause of clinical failures. While conventional in vitro methods of drug discovery do not truly represent the human system, the animal models used for in vivo validation are also genetically and phenotypically distant from humans. However, recent developments in organoid culture are motivating and elevate hopes for replacing test animals with artificial human tissue models. 

Possibility of creating functional tissue ex vivo has a potential to revolutionize the way human therapeutics is perceived. Not only will it bridge the gap between drug development and its clinical efficacy but also help strategizing regenerative medicine. Successful human-tissue surrogates would liberate test animals or at least minimize their use for research purposes. Potential drug candidates tested on human-tissue equivalents are expected to generate clinically much more relevant data. Here we deliberate upon the options and possibilities of accomplishing human organoid models for in vitro testing and their significance in therapeutics.

Human-Organoid Models: Accomplishments to Salvage Test-Animals

Late stage attritions in drug discovery are costly and consuming. Improbable response of test molecules acquired in non-human systems is attributed to be the major cause of clinical failures. While conventional in vitro methods of drug discovery do not truly represent the human system, the animal models used for in vivo validation are also genetically and phenotypically distant from humans. However, recent developments in organoid culture are motivating and elevate hopes for replacing test animals with artificial human tissue models. 

Possibility of creating functional tissue ex vivo has a potential to revolutionize the way human therapeutics is perceived. Not only will it bridge the gap between drug development and its clinical efficacy but also help strategizing regenerative medicine. Successful human-tissue surrogates would liberate test animals or at least minimize their use for research purposes. Potential drug candidates tested on human-tissue equivalents are expected to generate clinically much more relevant data. Here we deliberate upon the options and possibilities of accomplishing human organoid models for in vitro testing and their significance in therapeutics.