Extensive Properties
Extensive Properties - Related Videos
28:40
Proboscis Extension Response (PER) Assay in Drosophila
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Cited by 114 •
2007
Proboscis extension response or PER is a taste behavior assay that has been used in flies as well as in honeybees. When the proboscis makes contact with an attractive substance, the fly extends its proboscis to consume the substance. Solutions of various sugars are very attractive to the fly.
03:32
Using a Macrophage Conditioned Medium to Promote Neuron Extensions
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2025
This video demonstrates an assay for promoting the growth of neuron projections known as neurite outgrowth using the macrophage-conditioned medium. Co-culture neurons and macrophages with cAMP and harvest the macrophage-derived conditioned medium. Growing the neurons with the conditioned medium promotes neurite outgrowths. These outgrowths are fluorescently labeled and visualized using a fluorescence microscope.
09:51
Measuring Plant Cell Wall Extension (Creep) Induced by Acidic pH and by Alpha-Expansin
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Cited by 41 •
2009
We demonstrate the use of a constant-force extensometer to measure long-term extension (creep) of plant cell wall specimens induced by acidic buffers and expansin protein.
07:03
Initiating Rapid Neurite Extension and Formation Functional Neuronal Connections
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2025
This video demonstrates a technique for the rapid initiation and extension of a neuron and creation of new connections with a target neuron using a microfluidic device and micromanipulation. This could be used for therapies that aim to reconnect neuronal circuits after trauma or in neurodegenerative diseases.
15:28
Primer Extension Capture: Targeted Sequence Retrieval from Heavily Degraded DNA Sources
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Cited by 43 •
2009
We present a method of targeted ancient DNA sequence retrieval, which we used to reconstruct the complete mitochondrial genomes of five Neandertal individuals. Comparison of these sequences with present day humans suggests that Neandertals had a long term low effective population size.
FAQs
Additivity follows when a quantity is defined for the combined system and contributions from the individual portions can be included in the whole. For example, the total mass, volume, amount of substance, or energy can be obtained by summing the corresponding values for the separate systems. This provides a direct way to connect component measurements with whole-system descriptions.
Dividing an extensive quantity by mass, amount of substance, or another measure of system size removes dependence on how much material is present. The resulting intensive quantity supports comparisons between samples of different sizes. This conversion is useful when two chemical systems contain unequal amounts but need to be evaluated using a common basis.
Extensive properties describe the total content or size of a system, whereas intensive properties provide a size-independent basis for comparison. A total value can therefore be converted into a normalized value by dividing by mass, moles, or another size measure. Choosing between these forms helps determine whether a calculation concerns an entire sample or a comparable portion of it.
A material balance starts with whole-system quantities and relates them to the quantities entering, leaving, or forming within the system. Because extensive amounts can be combined, measurements for individual streams or components can be summed to describe the system total. This approach helps organize chemical information and connect measured amounts with the overall composition of a process.
Stoichiometric calculations often require totals such as mass or amount of substance for reactants and products. Extensive quantities let the calculation represent the actual quantity of material in a sample rather than only a normalized value. By relating component amounts to the whole system, chemists can use measured material quantities to evaluate chemical composition and reaction relationships.
Thermodynamic analysis frequently concerns total energy and other quantities associated with an entire chemical system. Extensive values allow separate portions or components to be related to the system total, which supports analysis of combined materials and system-level changes. When useful comparisons require different sample sizes, dividing by mass or amount of substance provides a normalized perspective.