Media Exchange
Media Exchange - Related Videos
11:38
Heat Exchanger Analysis
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2023
Source: Alexander S Rattner and Christopher J Greer; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA Heat exchangers transfer thermal energy between two fluid streams, and are ubiquitous in energy systems. Common applications include car radiators (heat transfer from hot engine coolant to surrounding air), refrigerator evaporators (air inside refrigerator compartment to evaporating refrigerant), and cooling towers in power plants...
02:06
Social Exchange Theory
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2020
We have discussed why we form relationships, what attracts us to others, and different types of love. But what determines whether we are satisfied with and stay in a relationship? One theory that provides an explanation is social exchange theory. According to social exchange theory, we act as naïve economists in keeping a tally of the ratio of costs and benefits of forming and maintaining a relationship with others (Rusbult & Van Lange, 2003). People are motivated to maximize the benefits...
01:20
Gas Exchange and Transport
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2019
Gas exchange, the intake of molecular oxygen (O2) from the environment and the outflow of carbon dioxide (CO2) into the environment, is necessary for cellular function. Gas exchange during respiration occurs largely via the movement of gas molecules along pressure gradients. Gas travels from areas of higher partial pressure to areas of lower partial pressure. In mammals, gas exchange occurs in the alveoli of the lungs, which are adjacent to capillaries and share a membrane with them. When the...
08:52
Ion-Exchange Chromatography
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2023
Source: Laboratory of Dr. B. Jill Venton - University of Virginia Ion-exchange chromatography is a type of chromatography that separates analytes based on charge. A column is used that is filled with a charged stationary phase on a solid support, called an ion-exchange resin. Strong cation-exchange chromatography preferentially separates out cations by using a negatively-charged resin while strong anion-exchange chromatography preferentially selects out anions by using a positively-charged...
01:28
Capillary Exchange
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2024
The cardiovascular system's chief role is to disseminate gases, nutrients, waste, and other substances to the body's cells. Small molecules like gases, lipids, and lipid-soluble substances directly diffuse through capillary wall endothelial cell membranes. Glucose, amino acids, and ions, including sodium, potassium, calcium, and chloride, use transporters for facilitated diffusion via membrane-specific channels. Glucose, ions, and bigger molecules may also pass through intercellular clefts.
FAQs
As cells consume nutrients and release metabolic waste, the culture environment can move away from conditions that support growth. Replacing spent medium restores available nutrients while reducing accumulated waste, helping maintain pH, osmolarity, and related chemical conditions. This balance is important because environmental instability can affect cell viability, growth consistency, and the interpretation of experimental results.
The appropriate timing depends on how quickly a system changes its medium environment and on the needs of the experiment. Mammalian cells, primary cells, stem cells, organoids, and microbial systems may differ in their sensitivity to depleted nutrients or accumulated waste. Careful scheduling therefore supports stable growth while reducing unnecessary handling and culture stress.
Aseptic handling protects the culture while spent medium is removed and fresh medium is introduced. Because the exchange directly opens or contacts the culture environment, poor handling can compromise the controlled conditions needed for reliable growth. Maintaining aseptic conditions helps preserve cell viability and strengthens reproducibility in studies that depend on consistent culture performance.
A basic workflow consists of withdrawing the spent medium, replacing it with fresh medium, and maintaining aseptic conditions throughout the operation. The exchange should be performed with timing appropriate to the culture and experiment, while preserving the chemical environment needed for growth. Consistent execution helps limit avoidable variation between cultures and experimental runs.
The main conditions include nutrient availability, accumulated metabolic waste, pH, osmolarity, and overall growth suitability. After an exchange, these factors provide a framework for judging whether the culture environment has been stabilized. Outcomes of interest may include improved cell viability, more consistent growth, and greater reproducibility across drug testing or other biological experiments.
This practice supports a broad range of systems, including mammalian cell cultures, primary cells, stem cells, organoids, and microbial cultures. It is relevant to drug testing, tissue engineering, and bioprocessing because these applications require controlled growth conditions and dependable experimental performance. In each setting, exchange timing and handling influence how consistently the system can be maintained and studied.