The present protocol describes the capabilities and the essential culture modalities of the Open-Top Organ-Chip for the successful establishment and maturation of full-thickness organ-on-chip cultures of primary tissues (skin, alveolus, airway, and intestine), providing the opportunity to investigate different functional aspects of the human epithelial/mesenchymal and vascular niche interface in...

Opportunity cost refers to the value of the next best alternative that must be forgone when making a decision. It represents the potential benefits or opportunities sacrificed when choosing one option over another. Understanding opportunity cost is essential in decision-making as it helps individuals, businesses, and societies assess the true cost of their choices.
In life, every decision involves trade-offs, where opting for one alternative means giving up another. For example, pursuing higher...

The frequency-domain technique, commonly used in analyzing and designing feedback control systems, is effective for linear, time-invariant systems. However, it falls short when dealing with nonlinear, time-varying, and multiple-input multiple-output systems. The time-domain or state-space approach addresses these limitations by utilizing state variables to construct simultaneous, first-order differential equations, known as state equations, for an nth-order system.
Consider an RLC circuit, a...

A space truss is a three-dimensional counterpart of a planar truss. These structures consist of members connected at their ends, often utilizing ball-and-socket joints to create a stable and versatile framework. The space truss is widely used in various construction projects due to its adaptability and capacity to withstand complex loads.
At the core of a space truss lies the fundamental unit known as the tetrahedron. This structure is composed of six members that form a three-dimensional shape...

Sunk costs are expenditures already made and cannot be recovered, irrespective of future choices. These costs are essentially "sunk" because they are irretrievable and should not influence future decision-making. On the contrary, opportunity costs denote the value of the best alternative forgone when a decision is taken.
For example, if a company invests in a failing project, the money already spent on it is considered a sunk cost. However, the opportunity cost of continuing with the...

Simple and reproducible procedures are described for making three structurally distinct collagen assemblies from a common commercially available Type I collagen monomer. Native type, fibrous long spacing or segmental long spacing collagen can be constructed by varying the conditions to which the 300 nm long and 1.4 nm diameter monomer building block is...