PubMed Health⌕ Search

Biomedical subjects

Jean Luc Lévêque

Publications and source records attributed to Jean Luc Lévêque.

6 recordsLinked to original sources
PubMed2006

Capacitance imaging of the skin surface.

BACKGROUND/AIMS: A new device allowing recording capacitance images of the skin surface was recently presented. Parameters, extracted from the gray-level histogram of the images, are tested for a new approach of skin surface hydration measurement in comparison with the classical capacitance method. Illustration of the interest of having both images and parameters for studying the homogeneity and the level of skin surface hydration are presented. METHODS: Software for selecting a region of interest from an image and measuring the parameters derived from its gray-level histogram was used to characterize skin hydration. RESULTS: There is a very close correlation between a Corneometer and the parameters extracted from the SkinChip measurements. The importance of having capacitance images of skin is demonstrated in case of non-homogeneity of the skin hydration, either because of photoaging or following an inflammation process. CONCLUSION: Capacitance imaging is a necessary tool for both completely describing and quantifying skin surface hydration.

Dermatitis↗
PubMed2005

Silicon image sensor technology for in vivo detection of surfactant-induced corneocyte swelling and drying.

BACKGROUND: Several instrumental methods can indirectly assess some specific aspects of cutaneous irritation at the level of the stratum corneum (SC). OBJECTIVE: There is a need for developing more sensitive approaches in this field. METHODS: We assessed a recently introduced innovative tool (SkinChip) based on capacitive pixel-sensing technology in its potential to detect early discrete manifestations of skin irritation. The sensor generates a detailed non-optical picture corresponding to a capacitance map of the skin surface reaching 50 microm pixel resolution. Some topographical details can be easily disclosed and the SC hydration as well. Two surfactant solutions were tested on volunteers. These solutions were applied under test patches for 2 days on the volar forearms. Clinical and SkinChip assessments were performed 3 h after removing the patch. RESULTS: The generated images allowed a precise observation of skin irritation which appeared as a two-step process. Early changes consisted of darker pixels corresponding to overhydrated swollen corneocytes at the irritated sites. Two days later, the same area appeared as white pixels, indicating the loss of corneocyte hydration. CONCLUSION: The SkinChip device appears to be a very sensitive tool for detecting the early steps of surfactant-induced skin irritation affecting the SC.

Dermatitis, Irritant↗
PubMed2003

The "Haptic Finger"- a new device for monitoring skin condition.

BACKGROUND/AIMS: Touching the skin is of great importance for the Clinician for assessing roughness, softness, firmness, etc. This type of clinical assessment is very subjective and therefore non-reproducible from one Clinician to another one or even from time to time for the same Clinician. In order to objectively monitor skin texture, we developed a new sensor, placed directly on the Clinician's finger, which generate some electric signal when slid over the skin surface. MATERIAL AND METHODS: The base of this Haptic Finger sensor is a thin stainless steel plate on which sponge rubber, PVDF foil, acetate film and gauze are layered. The signal generated by the sensor was filtered and digitally stored before processing. In a first in vitro experiment, the sensor was moved over different skin models (sponge rubber covered by silicon rubber) of varying hardness and roughness. These experiments allowed the definition of two parameters characterizing textures. The first parameter is variance of the signal processed using wavelet analysis, representing an index of roughness. The second parameter is dispersion of the power spectrum density in the frequency domain, corresponding to hardness. To validate these parameters, the Haptic Finger was used to scan skin surfaces of 30 people, 14 of whom displayed a skin disorder: xerosis (n = 5), atopic dermatitis (n = 7), and psoriasis (n = 2). RESULTS AND CONCLUSION: The results obtained by means of the sensor were compared with subjective, clinical evaluations by a Clinician who scored both roughness and hardness of the skin. Good agreement was observed between clinical assessment of the skin and the two parameters generated using the Haptic Finger. Use of this sensor could prove extremely valuable in cosmetic research where skin surface texture (in terms of tactile properties) is difficult to measure.

Dermatology↗
PubMed2003

SkinChip, a new tool for investigating the skin surface in vivo.

BACKGROUND/AIMS: Non-invasive methods used for characterizing skin micro-relief and skin surface hydration were developed in the 1980s. Although they allowed some progress in the knowledge of skin properties, they are not completely satisfactory in many aspects. Today, new technologies are emerging that may address such issues. METHODS: We adapted the technology produced by the ST Microelectronics Company for sensing fingerprint for the measurement of skin surface properties. Accordingly, we developed acquisition software for obtaining routinely the distribution of skin surface capacitance along different body sites. Image analysis softwares were also processed for collecting both the main orientations of the micro-relief lines and their density. The average value of skin capacitance is also obtained. RESULTS: The images allow a highly precise observation of the skin topography that can be easily quantified in terms of line density and line orientation. The mean gray levels of the images appear much closely correlated to the Corneometer values. CONCLUSION: This new device appears to be a very convenient way for characterizing the properties of the skin surface. With regard to hydration, it usefully provides both the average value and the hydration chart of the investigated skin zones.

Face↗
PubMed2002

A computational skin model: fold and wrinkle formation.

This paper presents a computational model for studying the mechanical properties of skin with aging. In particular, attention is given to the folding capacity of skin, which may be manifested as wrinkles. The simulation provides visual results demonstrating the form and density of folds under the various conditions. This can help in the consideration of proper measures for a cosmetic product for the skin.

Aging↗