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Publications (10 of 12) Show all publications
Sjövall, P., Skedung, L., Gregoire, S., Biganska, O., Clément, F. & Luengo, G. S. (2018). Imaging the distribution of skin lipids and topically applied compounds in human skin using mass spectrometry. Scientific Reports, 8(1), Article ID 16683.
Open this publication in new window or tab >>Imaging the distribution of skin lipids and topically applied compounds in human skin using mass spectrometry
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, no 1, article id 16683Article in journal (Refereed) Published
Abstract [en]

The barrier functions of skin against water loss, microbial invasion and penetration of xenobiotics rely, in part, on the spatial distribution of the biomolecular constituents in the skin structure, particularly its horny layer (stratum corneum). However, all skin layers are important to describe normal and dysfunctional skin conditions, and to develop adapted therapies or skin care products. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) combined with scanning electron microscopy (SEM) was used to image the spatial distribution of a variety of molecular species, from stratum corneum down to dermis, in cross-section samples of human abdominal skin. The results demonstrate the expected localization of ceramide and saturated long-chain fatty acids in stratum corneum (SC) and cholesterol sulfate in the upper part of the viable epidermis. The localization of exogenous compounds is demonstrated by the detection and imaging of carvacrol (a constituent of oregano or thyme essential oil) and ceramide, after topical application onto ex vivo human skin. Carvacrol showed pronounced accumulation to triglyceride-containing structures in the deeper parts of dermis. In contrast, the exogenous ceramide was found to be localized in SC. Furthermore, the complementary character of this approach with classical ex vivo skin absorption analysis methods is demonstrated.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36385 (URN)10.1038/s41598-018-34286-x (DOI)30420715 (PubMedID)2-s2.0-85056347342 (Scopus ID)
Available from: 2018-11-22 Created: 2018-11-22 Last updated: 2019-06-19Bibliographically approved
Skedung, L., El Rawadi, C., Arvidsson, M., Farcet, C., Luengo, G. S., Breton, L. & Rutland, M. W. (2018). Mechanisms of tactile sensory deterioration amongst the elderly. Scientific Reports, 8(1), Article ID 5303.
Open this publication in new window or tab >>Mechanisms of tactile sensory deterioration amongst the elderly
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, no 1, article id 5303Article in journal (Refereed) Published
Abstract [en]

It is known that roughness-smoothness, hardness-softness, stickiness-slipperiness and warm-cold are predominant perceptual dimensions in macro-, micro- and nano- texture perception. However, it is not clear to what extent active tactile texture discrimination remains intact with age. The general decrease in tactile ability induces physical and emotional dysfunction in elderly, and has increasing significance for an aging population. We report a method to quantify tactile acuity based on blinded active exploration of systematically varying micro-textured surfaces and a same-different paradigm. It reveals that elderly participants show significantly reduced fine texture discrimination ability. The elderly group also displays statistically lower finger friction coefficient, moisture and elasticity, suggesting a link. However, a subpopulation of the elderly retains discrimination ability irrespective of cutaneous condition and this can be related to a higher density of somatosensory receptors on the finger pads. Skin tribology is thus not the primary reason for decline of tactile discrimination with age. The remediation of cutaneous properties through rehydration, however leads to a significantly improved tactile acuity. This indicates unambiguously that neurological tactile loss can be temporarily compensated by restoring the cutaneous contact mechanics. Such mechanical restoration of tactile ability has the potential to increase the quality of life in elderly. 

Keywords
aged, article, controlled study, deterioration, elasticity, finger, friction, human, moisture, quality of life, rehydration, skin, tactile discrimination
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33788 (URN)10.1038/s41598-018-23688-6 (DOI)2-s2.0-85045892223 (Scopus ID)
Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-08-17Bibliographically approved
Arvidsson, M., Ringstad, L., Skedung, L., Duvefelt, K. & Rutland, M. W. (2017). Feeling fine - the effect of topography and friction on perceived roughness and slipperiness. Biotribology, 11, 92-101
Open this publication in new window or tab >>Feeling fine - the effect of topography and friction on perceived roughness and slipperiness
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2017 (English)In: Biotribology, ISSN 2352-5738, Vol. 11, p. 92-101Article in journal (Refereed) Published
Abstract [en]

(1) Background. To design materials with specific haptic qualities, it is important to understand both the contribution of physical attributes from the surfaces of the materials and the perceptions that are involved in the haptic interaction. (2) Methods. A series of 16 wrinkled surfaces consisting of two similar materials of different elastic modulus and 8 different wrinkle wavelengths were characterized in terms of surface roughness and tactile friction coefficient. Sixteen participants scaled the perceived Roughness and Slipperiness of the surfaces using free magnitude estimation. Friction experiments were performed both by participants and by a trained experimenter with higher control. (3) Results and discussion. The trends in friction properties were similar for the group of participants performing the friction measurements in an uncontrolled way and the experiments performed under well-defined conditions, showing that the latter type of measurements represent the general friction properties well. The results point to slipperiness as the key perception dimension for textures below 100. μm and roughness above 100. μm. Furthermore, it is apparent that roughness and slipperiness perception of these types of structures are not independent. The friction is related to contact area between finger and material. Somewhat surprising was that the material with the higher elastic modulus was perceived as more slippery. A concluding finding was that the flat (high friction) reference surfaces were scaled as rough, supporting the theory that perceived roughness itself is a multidimensional construct with both surface roughness and friction component.

Keywords
Friction, Roughness, Slipperiness, Tactile perception
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-31183 (URN)10.1016/j.biotri.2017.01.002 (DOI)2-s2.0-85023162786 (Scopus ID)
Note

Export Date: 23 August 2017; Article in Press

Available from: 2017-08-23 Created: 2017-08-23 Last updated: 2019-07-05Bibliographically approved
Duvefelt, K., Olofsson, U., Johannesson, C. M. & Skedung, L. (2016). Model for contact between finger and sinusoidal plane to evaluate adhesion and deformation component of friction. Tribology International, 96, 389-394
Open this publication in new window or tab >>Model for contact between finger and sinusoidal plane to evaluate adhesion and deformation component of friction
2016 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 96, p. 389-394Article in journal (Refereed) Published
Abstract [en]

One of the main parameters affecting finger friction, friction-induced vibrations in the finger, and consequently tactility is surface topography. Recently Skedung et al. performed finger friction measurements on fine controlled surfaces. These surfaces were sinusoidal with wavelengths from 0.27 to 8.8 μm and amplitudes from 0.007 to 6 μm. Building on those tests an analytical model for the contact was developed to explain the differences in friction coefficient. The contact was modelled as trapezoids in a circular pattern pressed against a sinusoidal plane. Results showed that the calculated contact area and therefore friction coefficient corresponded well with the measurements. This model can be used to see how the different surface parameters influence friction.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
adhesion, contact area, finger, friction
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear) Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:ri:diva-77 (URN)10.1016/j.triboint.2014.12.020 (DOI)2-s2.0-84959542022 (Scopus ID)
Available from: 2016-04-28 Created: 2016-04-28 Last updated: 2019-06-17Bibliographically approved
Skedung, L., Buraczewska-Norin, I., Dawood, N., Rutland, M. W. & Ringstad, L. (2016). Tactile friction of topical formulations. Skin research and technology, 22(1), 46-54
Open this publication in new window or tab >>Tactile friction of topical formulations
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2016 (English)In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 22, no 1, p. 46-54Article in journal (Refereed) Published
Abstract [en]

Background: The tactile perception is essential for all types of topical formulations (cosmetic, pharmaceutical, medical device) and the possibility to predict the sensorial response by using instrumental methods instead of sensory testing would save time and cost at an early stage product development. Here, we report on an instrumental evaluation method using tactile friction measurements to estimate perceptual attributes of topical formulations. Methods: Friction was measured between an index finger and an artificial skin substrate after application of formulations using a force sensor. Both model formulations of liquid crystalline phase structures with significantly different tactile properties, as well as commercial pharmaceutical moisturizing creams being more tactile-similar, were investigated. Friction coefficients were calculated as the ratio of the friction force to the applied load. The structures of the model formulations and phase transitions as a result of water evaporation were identified using optical microscopy. Results: The friction device could distinguish friction coefficients between the phase structures, as well as the commercial creams after spreading and absorption into the substrate. In addition, phase transitions resulting in alterations in the feel of the formulations could be detected. A correlation was established between skin hydration and friction coefficient, where hydrated skin gave rise to higher friction. Also a link between skin smoothening and finger friction was established for the commercial moisturizing creams, although further investigations are needed to analyse this and correlations with other sensorial attributes in more detail. Conclusion: The present investigation shows that tactile friction measurements have potential as an alternative or complement in the evaluation of perception of topical formulations.

Place, publisher, year, edition, pages
Blackwell Publishing, 2016
Keywords
finger/tactile friction, hydration, moisturizers, skin friction, tactile perception, topical formulations
National Category
Condensed Matter Physics Other Chemistry Topics
Identifiers
urn:nbn:se:ri:diva-98 (URN)10.1111/srt.12227 (DOI)2-s2.0-84952838395 (Scopus ID)
Available from: 2016-05-31 Created: 2016-04-28 Last updated: 2019-06-19Bibliographically approved
Duvefelt, K., Olofsson, U., Johannesson, C. M. & Skedung, L. (2014). Model for contact between finger and sinusoidal plane to evaluate adhesion and deformation component of friction (ed.). Tribology International, 389-394
Open this publication in new window or tab >>Model for contact between finger and sinusoidal plane to evaluate adhesion and deformation component of friction
2014 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, p. 389-394Article in journal (Refereed) Published
Abstract [en]

One of the main parameters affecting finger friction, friction-induced vibrations in the finger, and consequently tactility is surface topography. Recently Skedung et al. performed finger frictionmeasurements on fine controlled surfaces. These surfaces were sinusoidal with wavelengths from 0.27 to 8.8 μm and amplitudes from 0.007 to 6 μm. Building on those tests an analytical model for the contact was developed to explain the differences in friction coefficient. The contact was modelled as trapezoids in a circular pattern pressed against a sinusoidal plane. Results showed that the calculated contact area and therefore friction coefficient corresponded well with the measurements. This model can be used to see how the different surface parameters influence friction.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6739 (URN)10.1016/j.triboint.2014.12.020 (DOI)2-s2.0-84959542022 (Scopus ID)23760 (Local ID)23760 (Archive number)23760 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2019-08-14Bibliographically approved
Skedung, L. & Rutland, M. (2013). Feeling small: Exploring the tactile perception limits (ed.). Scientific Reports, 3, 2617
Open this publication in new window or tab >>Feeling small: Exploring the tactile perception limits
2013 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, p. 2617-Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6541 (URN)23821 (Local ID)23821 (Archive number)23821 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2018-08-15Bibliographically approved
Skedung, L., Ringstad, L. & Rutland, M. (2013). Tactile friction of topical formulations (ed.). In: 5th World Tribology Congress, WTC 2013: . Paper presented at 5th World Tribology Congress, WTC 2013; The Palaolimpico Isozaki TorinoC.so SebastopoliTorino; Italy; Sept. 8 through 13 Sept. 13, 2013.
Open this publication in new window or tab >>Tactile friction of topical formulations
2013 (English)In: 5th World Tribology Congress, WTC 2013, 2013, , p. 2249-2251Conference paper, Published paper (Refereed)
Publisher
p. 2249-2251
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-12456 (URN)23663 (Local ID)23663 (Archive number)23663 (OAI)
Conference
5th World Tribology Congress, WTC 2013; The Palaolimpico Isozaki TorinoC.so SebastopoliTorino; Italy; Sept. 8 through 13 Sept. 13, 2013
Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2018-08-15Bibliographically approved
Skedung, L. & Rutland, M. (2013). Tribology, texture and touch (ed.). In: 5th World Tribology Congress, WTC 2013: . Paper presented at 5th World Tribology Congress, WTC 2013. The Palaolimpico Isozaki TorinoC.so SebastopoliTorino; Italy; Sept. 8 through Sept. 13, 2013.
Open this publication in new window or tab >>Tribology, texture and touch
2013 (English)In: 5th World Tribology Congress, WTC 2013, 2013, , p. 2270-2273Conference paper, Published paper (Refereed)
Publisher
p. 2270-2273
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-12455 (URN)23662 (Local ID)23662 (Archive number)23662 (OAI)
Conference
5th World Tribology Congress, WTC 2013. The Palaolimpico Isozaki TorinoC.so SebastopoliTorino; Italy; Sept. 8 through Sept. 13, 2013
Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2018-08-15Bibliographically approved
Hansson, P. M., Skedung, L., Claesson, P. M., Swerin, A., Schoelkopf, J. & Gane, P. A. (2011). Robust hydrophobic surfaces displaying different surface roughness scales while maintaining the same wettability (ed.). Langmuir, 27(13), 8153-8159
Open this publication in new window or tab >>Robust hydrophobic surfaces displaying different surface roughness scales while maintaining the same wettability
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2011 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, no 13, p. 8153-8159Article in journal (Refereed) Published
Abstract [en]

A range of surfaces coated with spherical silica particles, covering the size range from nanometer to micrometer, have been produced using Langmuir-Blodgett (LB) deposition. The particles were characterized both in suspension and in the Langmuir trough to optimize the surface preparation procedure. By limiting the particle aggregation and surface layer failures during the preparation steps, well-defined monolayers with a close-packed structure have been obtained for all particle sizes. Thus, this procedure led to structured surfaces with a characteristic variation in the amplitude and spatial roughness parameters. In order to obtain robust surfaces, a sintering protocol and an AFM-based wear test to determine the stability of the deposited surface layer were employed. Hydrophobization of the LB films followed by water contact angle measurements showed, for all tested particle sizes, the same increase in contact angle compared to the contact angle of a flat hydrophobic surface. This indicates nearly hexagonal packing and gives evidence for nearly, complete surface wetting of the surface features.

Keywords
Robust hydrophobic surfaces displaying different surface roughness scales while maintaining the same wettability
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-27106 (URN)10.1021/la201121p (DOI)
Note

A3007

Available from: 2016-12-08 Created: 2016-12-08 Last updated: 2018-08-15Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6657-1592

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