Maintenance; Elasticity; Principle - Cortexa Technology DermaLab Mini Instructions For Use Manual

7.6 Maintenance

Except for keeping the probes clean, there is no preventive maintenance associated with the use
of the hydration probes. To clean the probe front, simply wipe it off using a dry cloth. Should more
thorough cleaning be necessary, a drop of alcohol may be applied to the cloth.
Instrument performance in terms of calibration may be checked by obtaining an optional calibra-
tion checker (phantom). Press the phantom against the probe making sure to establish good elec-
trical contact to the probe face (two pins in case of pin-probe) and perform a normal measure-
ment. A moisture reading of 1000  3% is considered normal.

8 Elasticity

8.1 Principle

The elasticity measurement of the DermaLab
face. The probe provides a suction chamber and uses adhesive tape to prevent creeping and fold-
ing of the skin under the edge surrounding the measurement chamber. It is connected to the main
unit, which accommodates an integrated negative pressure cylinder. This cylinder holds a preset
negative pressure of 150/400/650 mbar reflecting the Soft/Normal/Firm setting in the software.
By pressing "Sample", this negative pressure is instantly applied to the skin surface and, conse-
quently, the skin response is a direct function of the skin properties.
The suction method features an elevation phase and a retraction phase, the properties of which
both contribute to the "feel" of the skin.
As an example, young and smooth delicate skin, which is well moisturized, will normally be rela-
tively easy to elevate by applying suction, and it will retract rapidly.
Old and loose skin will also be easy to elevate, however, it will not retract rapidly. Therefore, what
is usually considered to be skin elasticity (or smoothness, softness, firmness) is of a more com-
plex nature and is best measured by taking both the elevation and retraction phase into account.
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The DermaLab Mini offers three descriptive parameters for the skin elasticity:
1. Young´s elasticity modulus (E),
2. Skin retraction time (R)
3. ViscoElasticity (VE) combining both the elevation and
retraction phase.
The three parameters are explained below. Which parameter(s) to choose may depend on study
design and personal preference.
1) Young´s elasticity modulus.
Calculation of Youngs elasticity modulus (E) is based on measuring the distance the skin can be
lifted, when applying a specific and preset vacuum to the skin inside the probe chamber. The
Young's modulus is calculated using the following equation:
x = elevation of the skin measured at the middle of surface (in m)

= constant (here set to 0.5)
p = surface pressure (in Pa)
E = elasticity modulus (in MPa)
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Mini is based on suction applied to the skin sur-
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  
E = p where:
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