Measuring skin conductance over clothes.

PubMed

Hong, Ki Hwan; Lee, Seung Min; Lim, Yong Gyu; Park, Kwang Suk

2012-11-01

We propose a new method that measures skin conductance over clothes to nonintrusively monitor the changes in physiological conditions affecting skin conductance during daily activities. We selected the thigh-to-thigh current path and used an indirectly coupled 5-kHz AC current for the measurement. While varying the skin conductance by the Valsalva maneuver method, the results were compared with the traditional galvanic skin response (GSR) measured directly from the fingers. Skin conductance measured using a 5-kHz current displayed a highly negative correlation with the traditional GSR and the current measured over clothes reflected the rate of change of the conductance of the skin beneath.

A quantitative study of nanoparticle skin penetration with interactive segmentation.

PubMed

Lee, Onseok; Lee, See Hyun; Jeong, Sang Hoon; Kim, Jaeyoung; Ryu, Hwa Jung; Oh, Chilhwan; Son, Sang Wook

2016-10-01

In the last decade, the application of nanotechnology techniques has expanded within diverse areas such as pharmacology, medicine, and optical science. Despite such wide-ranging possibilities for implementation into practice, the mechanisms behind nanoparticle skin absorption remain unknown. Moreover, the main mode of investigation has been qualitative analysis. Using interactive segmentation, this study suggests a method of objectively and quantitatively analyzing the mechanisms underlying the skin absorption of nanoparticles. Silica nanoparticles (SNPs) were assessed using transmission electron microscopy and applied to the human skin equivalent model. Captured fluorescence images of this model were used to evaluate degrees of skin penetration. These images underwent interactive segmentation and image processing in addition to statistical quantitative analyses of calculated image parameters including the mean, integrated density, skewness, kurtosis, and area fraction. In images from both groups, the distribution area and intensity of fluorescent silica gradually increased in proportion to time. Since statistical significance was achieved after 2 days in the negative charge group and after 4 days in the positive charge group, there is a periodic difference. Furthermore, the quantity of silica per unit area showed a dramatic change after 6 days in the negative charge group. Although this quantitative result is identical to results obtained by qualitative assessment, it is meaningful in that it was proven by statistical analysis with quantitation by using image processing. The present study suggests that the surface charge of SNPs could play an important role in the percutaneous absorption of NPs. These findings can help achieve a better understanding of the percutaneous transport of NPs. In addition, these results provide important guidance for the design of NPs for biomedical applications.

Skin reflectance as a non-lethal measure of smoltification for juvenile salmonids

USGS Publications Warehouse

Haner, Philip V.; Faler, Joyce C.; Schrock, Robin M.; Rondorf, Dennis W.; Maule, Alec G.

1995-01-01

Our efforts to find nonlethal methods of assessing the parr-smoll transformation of juvenile steelhead Oncorhynchus mykiss and spring and fall chinook salmon O. tshawytscha led to the development of a video system for quantitatively measuring skin silvering using skin reflectance. Gill Na'.K'-ATPase activity, skin guanine concentration, and skin reflectance were recorded from groups of fish marked with freeze brands at hatcheries and downstream sample sites in the Columbia River basin. Skin reflectance of migrants was significantly higher than that of fish before release; nonmigrants (released fish that did not migrate) had significantly lower skin reflectance than migrants from the same groups. Skin reflectance was significantly correlated with gill ATPasc activity and skin guanine concentration. Skin reflectance increased during the parrsmolt transformation and could be used as a nonlethal indicator of smoltification.

Quantitative analysis of dehydration in porcine skin for assessing mechanism of optical clearing

NASA Astrophysics Data System (ADS)

Yu, Tingting; Wen, Xiang; Tuchin, Valery V.; Luo, Qingming; Zhu, Dan

2011-09-01

Dehydration induced by optical clearing agents (OCAs) can improve tissue optical transmittance; however, current studies merely gave some qualitative descriptions. We develop a model to quantitatively evaluate water content with partial least-squares method based on the measurements of near-infrared reflectance spectroscopy and weight of porcine skin. Furthermore, a commercial spectrometer with an integrating sphere is used to measure the transmittance and reflectance of skin after treatment with different OCAs, and then the water content and optical properties of sample are calculated, respectively. The results show that both the reduced scattering coefficient and dehydration of skin decrease with prolongation of action of OCAs, but the relative change in former is larger than that in latter after a 60-min treatment. The absorption coefficient at 1450 nm decreases completely coincident with dehydration of skin. Further analysis illustrates that the correlation coefficient between the relative changes in the reduced scattering coefficient and dehydration is ~1 during the 60-min treatment of agents, but there is an extremely significant difference between the two parameters for some OCAs with more hydroxyl groups, especially, glycerol or D-sorbitol, which means that the dehydration is a main mechanism of skin optical clearing, but not the only mechanism.

Measurements and Characterizations of Mechanical Properties of Human Skins

NASA Astrophysics Data System (ADS)

Song, Han Wook; Park, Yon Kyu

A skin is an indispensible organ for humans because it contributes to metabolism using its own biochemical functions and protects the human body from external stimuli. Recently, mechanical properties such as a thickness, a friction and an elastic coefficient have been used as a decision index in the skin physiology and in the skin care market due to the increased awareness of wellbeing issues. In addition, the use of mechanical properties is known to have good discrimination ability in the classification of human constitutions, which are used in the field of an alternative medicine. In this study, a system that measures mechanical properties such as a friction and an elastic coefficient is designed. The equipment consists of a load cell type (manufactured by the authors) for the measurements of a friction coefficient, a decompression tube for the measurement of an elastic coefficient. Using the proposed system, the mechanical properties of human skins from different constitutions were compared, and the relative repeatability error for measurements of mechanical properties was determined to be less than 2%. Combining the inspection results of medical doctors in the field of an alternative medicine, we could conclude that the proposed system might be applicable to a quantitative constitutional diagnosis between human constitutions within an acceptable level of uncertainty.

Epidermal photonic devices for quantitative imaging of temperature and thermal transport characteristics of the skin

NASA Astrophysics Data System (ADS)

Gao, Li; Zhang, Yihui; Malyarchuk, Viktor; Jia, Lin; Jang, Kyung-In; Chad Webb, R.; Fu, Haoran; Shi, Yan; Zhou, Guoyan; Shi, Luke; Shah, Deesha; Huang, Xian; Xu, Baoxing; Yu, Cunjiang; Huang, Yonggang; Rogers, John A.

2014-09-01

Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we introduce an ultrathin, compliant skin-like, or ‘epidermal’, photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.

Epidermal photonic devices for quantitative imaging of temperature and thermal transport characteristics of the skin.

PubMed

Gao, Li; Zhang, Yihui; Malyarchuk, Viktor; Jia, Lin; Jang, Kyung-In; Webb, R Chad; Fu, Haoran; Shi, Yan; Zhou, Guoyan; Shi, Luke; Shah, Deesha; Huang, Xian; Xu, Baoxing; Yu, Cunjiang; Huang, Yonggang; Rogers, John A

2014-09-19

Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we introduce an ultrathin, compliant skin-like, or 'epidermal', photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.

Quantitative Methods for Measuring Repair Rates and Innate-Immune Cell Responses in Wounded Mouse Skin.

PubMed

Li, Zhi; Gothard, Elizabeth; Coles, Mark C; Ambler, Carrie A

2018-01-01

In skin wounds, innate-immune cells clear up tissue debris and microbial contamination, and also secrete cytokines and other growth factors that impact repair process such as re-epithelialization and wound closure. After injury, there is a rapid influx and efflux of immune cells at wound sites, yet the function of each innate cell population in skin repair is still under investigation. Flow cytometry is a valuable research tool for detecting and quantifying immune cells; however, in mouse back skin, the difficulty in extracting immune cells from small area of skin due to tissue complexity has made cytometric analysis an underutilized tool. In this paper, we provide detailed methods on the digestion of lesion-specific skin without disrupting antigen expression followed by multiplex cell staining that allows for identification of seven innate-immune populations, including rare subsets such as group-3 innate lymphoid cells (ILC3s), by flow-cytometry analysis. Furthermore, when studying the functions of immune cells to tissue repair an important metric to monitor is size of the wound opening. Normal wounds close steadily albeit at non-linear rates, while slow or stalled wound closure can indicate an underlying problem with the repair process. Calliper measurements are difficult and time-consuming to obtain and can require repeated sedation of experimental animals. We provide advanced methods for measuring of wound openness; digital 3D image capture and semi-automated image processing that allows for unbiased, reliable measurements that can be taken repeatedly over time.

Quantitative Methods for Measuring Repair Rates and Innate-Immune Cell Responses in Wounded Mouse Skin

PubMed Central

Li, Zhi; Gothard, Elizabeth; Coles, Mark C.; Ambler, Carrie A.

2018-01-01

In skin wounds, innate-immune cells clear up tissue debris and microbial contamination, and also secrete cytokines and other growth factors that impact repair process such as re-epithelialization and wound closure. After injury, there is a rapid influx and efflux of immune cells at wound sites, yet the function of each innate cell population in skin repair is still under investigation. Flow cytometry is a valuable research tool for detecting and quantifying immune cells; however, in mouse back skin, the difficulty in extracting immune cells from small area of skin due to tissue complexity has made cytometric analysis an underutilized tool. In this paper, we provide detailed methods on the digestion of lesion-specific skin without disrupting antigen expression followed by multiplex cell staining that allows for identification of seven innate-immune populations, including rare subsets such as group-3 innate lymphoid cells (ILC3s), by flow-cytometry analysis. Furthermore, when studying the functions of immune cells to tissue repair an important metric to monitor is size of the wound opening. Normal wounds close steadily albeit at non-linear rates, while slow or stalled wound closure can indicate an underlying problem with the repair process. Calliper measurements are difficult and time-consuming to obtain and can require repeated sedation of experimental animals. We provide advanced methods for measuring of wound openness; digital 3D image capture and semi-automated image processing that allows for unbiased, reliable measurements that can be taken repeatedly over time. PMID:29535723

Adhesion monitoring of skin grafts by photoacoustic measurement: experiment using rat allograft models

NASA Astrophysics Data System (ADS)

Yamazaki, Mutsuo; Sato, Shunichi; Saito, Daizo; Okada, Yoshiaki; Ashida, Hiroshi; Obara, Minoru

2004-07-01

Adhesion monitoring of grafted skins is very important in successful treatment of severe burns and traumas. However, current diagnosis of skin grafting is usually done by visual observation, which is not reliable and gives no quantitative information on the skin graft adhesion. When the grafted skin adheres well, neovascularities will be generated in the grafted skin tissue, and therefore adhesion may be monitored by detecting the neovascularities. In this study, we attempted to measure photoacoustic signals originate from the neovascularities by irradiating the grafted skins with 532-nm nanosecond light pulses in rat autograft and allograft models. The measurement showed that immediately after skin grafting, photoacoustic signal originate from the blood in the dermis was negligibly small, while 6 - 24 hours after skin grafting, signal was observed from the dermis in the graft. We did not observe a significant difference between the signals from the autograft and the allograft models. These results indicate that neovascularization would take place within 6 hours after skin grafting, and the rejection reaction would make little effect on adhesion within early hours after grafting.

Pig and guinea pig skin as surrogates for human in vitro penetration studies: a quantitative review.

PubMed

Barbero, Ana M; Frasch, H Frederick

2009-02-01

Both human and animal skin in vitro models are used to predict percutaneous penetration in humans. The objective of this review is a quantitative comparison of permeability and lag time measurements between human and animal skin, including an evaluation of the intra and inter species variability. We limit our focus to domestic pig and rodent guinea pig skin as surrogates for human skin, and consider only studies in which both animal and human penetration of a given chemical were measured jointly in the same lab. When the in vitro permeability of pig and human skin were compared, the Pearson product moment correlation coefficient (r) was 0.88 (P<0.0001), with an intra species average coefficient of variation of skin permeability of 21% for pig and 35% for human, and an inter species average coefficient of variation of 37% for the set of studied compounds (n=41). The lag times of pig skin and human skin did not correlate (r=0.35, P=0.26). When the in vitro permeability of guinea pig and human skin were compared, r=0.96 (P<0.0001), with an average intra species coefficient of variation of 19% for guinea pig and 24% for human, and an inter species coefficient of variation of permeability of 41% for the set of studied compounds (n=15). Lag times of guinea pig and human skin correlated (r=0.90, P<0.0001, n=12). When permeability data was not reported a factor of difference (FOD) of animal to human skin was calculated for pig skin (n=50) and guinea pig skin (n=25). For pig skin, 80% of measurements fell within the range 0.3skin, 65% fell within that range. Both pig and guinea pig are good models for human skin permeability and have less variability than the human skin model. The skin model of choice will depend on the final purpose of the study and the compound under investigation.

Skin Friction and Transition Location Measurement on Supersonic Transport Models

NASA Technical Reports Server (NTRS)

Kennelly, Robert A., Jr.; Goodsell, Aga M.; Olsen, Lawrence E. (Technical Monitor)

2000-01-01

Flow visualization techniques were used to obtain both qualitative and quantitative skin friction and transition location data in wind tunnel tests performed on two supersonic transport models at Mach 2.40. Oil-film interferometry was useful for verifying boundary layer transition, but careful monitoring of model surface temperatures and systematic examination of the effects of tunnel start-up and shutdown transients will be required to achieve high levels of accuracy for skin friction measurements. A more common technique, use of a subliming solid to reveal transition location, was employed to correct drag measurements to a standard condition of all-turbulent flow on the wing. These corrected data were then analyzed to determine the additional correction required to account for the effect of the boundary layer trip devices.

[Methods for measuring skin aging].

PubMed

Zieger, M; Kaatz, M

2016-02-01

Aging affects human skin and is becoming increasingly important with regard to medical, social and aesthetic issues. Detection of intrinsic and extrinsic components of skin aging requires reliable measurement methods. Modern techniques, e.g., based on direct imaging, spectroscopy or skin physiological measurements, provide a broad spectrum of parameters for different applications.

Infrared spectroscopic measurement of skin hydration and sebum levels and comparison to corneometer and sebumeter

NASA Astrophysics Data System (ADS)

Ezerskaia, Anna; Pereira, S. F.; Urbach, H. P.; Varghese, Babu

2016-05-01

Skin health characterized by a system of water and lipids in Stratum Corneum provide protection from harmful external elements and prevent trans-epidermal water loss. Skin hydration (moisture) and sebum (skin surface lipids) are considered to be important factors in skin health; a right balance between these components is an indication of skin health and plays a central role in protecting and preserving skin integrity. In this manuscript we present an infrared spectroscopic method for simultaneous and quantitative measurement of skin hydration and sebum levels utilizing differential detection with three wavelengths 1720, 1750, and 1770 nm, corresponding to the lipid vibrational bands that lie "in between" the prominent water absorption bands. The skin sebum and hydration values on the forehead under natural conditions and its variations to external stimuli were measured using our experimental set-up. The experimental results obtained with the optical set-up show good correlation with the results obtained with the commercially available instruments Corneometer and Sebumeter.

Quantitative analysis on collagen of dermatofibrosarcoma protuberans skin by second harmonic generation microscopy.

PubMed

Wu, Shulian; Huang, Yudian; Li, Hui; Wang, Yunxia; Zhang, Xiaoman

2015-01-01

Dermatofibrosarcoma protuberans (DFSP) is a skin cancer usually mistaken as other benign tumors. Abnormal DFSP resection results in tumor recurrence. Quantitative characterization of collagen alteration on the skin tumor is essential for developing a diagnostic technique. In this study, second harmonic generation (SHG) microscopy was performed to obtain images of the human DFSP skin and normal skin. Subsequently, structure and texture analysis methods were applied to determine the differences in skin texture characteristics between the two skin types, and the link between collagen alteration and tumor was established. Results suggest that combining SHG microscopy and texture analysis methods is a feasible and effective method to describe the characteristics of skin tumor like DFSP. © Wiley Periodicals, Inc.

Correction for tissue optical properties enables quantitative skin fluorescence measurements using multi-diameter single fiber reflectance spectroscopy.

PubMed

Middelburg, T A; Hoy, C L; Neumann, H A M; Amelink, A; Robinson, D J

2015-07-01

Fluorescence measurements in the skin are very much affected by absorption and scattering but existing methods to correct for this are not applicable to superficial skin measurements. The first use of multiple-diameter single fiber reflectance (MDSFR) and single fiber fluorescence (SFF) spectroscopy in human skin was investigated. MDSFR spectroscopy allows a quantification of the full optical properties in superficial skin (μa, μs' and γ), which can next be used to retrieve the corrected - intrinsic - fluorescence of a fluorophore Qμa,x(f). Our goal was to investigate the importance of such correction for individual patients. We studied this in 22 patients undergoing photodynamic therapy (PDT) for actinic keratosis. The magnitude of correction of fluorescence was around 4 (for both autofluorescence and protoporphyrin IX). Moreover, it was variable between patients, but also within patients over the course of fractionated aminolevulinic acid PDT (range 2.7-7.5). Patients also varied in the amount of protoporphyrin IX synthesis, photobleaching percentages and resynthesis (>100× difference between the lowest and highest PpIX synthesis). The autofluorescence was lower in actinic keratosis than contralateral normal skin (0.0032 versus 0.0052; P<0.0005). Our results clearly demonstrate the importance of correcting the measured fluorescence for optical properties, because these vary considerably between individual patients and also during PDT. Protoporphyrin IX synthesis and photobleaching kinetics allow monitoring clinical PDT which facilitates individual-based PDT dosing and improvement of clinical treatment protocols. Furthermore, the skin autofluorescence can be relevant for diagnostic use in the skin, but it may also be interesting because of its association with several internal diseases. Copyright © 2015 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

The reliability of non-invasive biophysical outcome measures for evaluating normal and hyperkeratotic foot skin.

PubMed

Hashmi, Farina; Wright, Ciaran; Nester, Christopher; Lam, Sharon

2015-01-01

Hyperkeratosis of foot skin is a common skin problem affecting people of different ages. The clinical presentation of this condition can range from dry flaky skin, which can lead to fissures, to hard callused skin which is often painful and debilitating. The purpose of this study was to test the reliability of certain non-invasive skin measurement devices on foot skin in normal and hyperkeratotic states, with a view to confirming their use as quantitative outcome measures in future clinical trials. Twelve healthy adult participants with a range of foot skin conditions (xerotic skin, heel fissures and plantar calluses) were recruited to the study. Measurements of normal and hyperkeratotic skin sites were taken using the following devices: Corneometer® CM 825, Cutometer® 580 MPA, Reviscometer® RVM 600, Visioline® VL 650 Quantiride® and Visioscan® VC 98, by two investigators on two consecutive days. The intra and inter rater reliability and standard error of measurement for each device was calculated. The data revealed the majority of the devices to be reliable measurement tools for normal and hyperkeratotic foot skin (ICC values > 0.6). The surface evaluation parameters for skin: SEsc and SEsm have greater reliability compared to the SEr measure. The Cutometer® is sensitive to soft tissue movement within the probe, therefore measurement of plantar soft tissue areas should be approached with caution. Reviscometer® measures on callused skin demonstrated an unusually high degree of error. These results confirm the intra and inter rater reliability of the Corneometer®, Cutometer®, Visioline® and Visioscan® in quantifying specific foot skin biophysical properties.

A flexible skin piloerection monitoring sensor

NASA Astrophysics Data System (ADS)

Kim, Jaemin; Seo, Dae Geon; Cho, Young-Ho

2014-06-01

We have designed, fabricated, and tested a capacitive-type flexible micro sensor for measurement of the human skin piloerection arisen from sudden emotional and environmental change. The present skin piloerection monitoring methods are limited in objective and quantitative measurement by physical disturbance stimulation to the skin due to bulky size and heavy weight of measuring devices. The proposed flexible skin piloerection monitoring sensor is composed of 3 × 3 spiral coplanar capacitor array using conductive polymer for having high capacitive density and thin enough thickness to be attached to human skin. The performance of the skin piloerection monitoring sensor is characterized using the artificial bump, representing human skin goosebump; thus, resulting in the sensitivity of -0.00252%/μm and the nonlinearity of 25.9% for the artificial goosebump deformation in the range of 0-326 μm. We also verified successive human skin piloerection having 3.5 s duration on the subject's dorsal forearms, thus resulting in the capacitance change of -6.2 fF and -9.2 fF for the piloerection intensity of 145 μm and 194 μm, respectively. It is demonstrated experimentally that the proposed sensor is capable to measure the human skin piloerection objectively and quantitatively, thereby suggesting the quantitative evaluation method of the qualitative human emotional status for cognitive human-machine interfaces applications.

A novel method to measure skin mechanical properties with three-dimensional digital image correlation.

PubMed

Xu, Z; Dela Cruz, J; Fthenakis, C; Saliou, C

2018-06-06

Measuring skin mechanical properties has been of great interest in the skincare industry. It is a high accuracy and non-invasive optical technique which quantitatively tracks skin movement and deformation under mechanical perturbations. A study was conducted with female subjects (25-65 years old). A refined speckle pattern applied onto the skin surface was used for DIC measurements. A unidirectional force pulled the skin at a constant velocity, while the deformation process was quantified by the DIC. Prior to the DIC measurement, Cutometer ® readings were taken on the same area. The DIC protocol's reproducibility across multiple pattern applications, the measurement's repeatability, and the sensitivity in differentiating skin mechanical properties were investigated. Subjects were clustered with statistical significance according to their skin mechanical properties described by six DIC metrics (μ [major strain], σ [major strain], μ [minor strain], σ [minor strain], μ [displacement], and σ [displacement]). Most measurement random errors are below 6%. This is several folds smaller in magnitude than the difference in the mean response between the clusters. Several Cutometer ® parameters also showed good agreement with μ (displacement). DIC was able to differentiate skins of different mechanical qualities. We also proposed the physical significance of the DIC metrics. Some of the DIC metrics potentially offer new insights into skin mechanical properties that complement those revealed by conventional instruments. Accurate measurements, large measurement areas along with ease of direct visualization are substantial advantages of DIC. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Accurate Measurements of the Skin Surface Area of the Healthy Auricle and Skin Deficiency in Microtia Patients

PubMed Central

van Doremalen, Rob F. M.; Melchels, Ferry P. W.; Kolodzynski, Michail N.; Pouran, Behdad; Malda, Jos; Kon, Moshe; Breugem, Corstiaan C.

2016-01-01

Background: The limited cranial skin covering auricular implants is an important yet underrated factor in auricular reconstruction for both reconstruction surgery and tissue engineering strategies. We report exact measurements on skin deficiency in microtia patients and propose an accessible preoperative method for these measurements. Methods: Plaster ear models (n = 11; male:female = 2:1) of lobular-type microtia patients admitted to the University Medical Center Utrecht in The Netherlands were scanned using a micro-computed tomographic scanner or a cone-beam computed tomographic scanner. The resulting images were converted into mesh models from which the surface area could be calculated. Results: The mean total skin area of an adult-size healthy ear was 47.3 cm2, with 49.0 cm2 in men and 44.3 cm2 in women. Microtia ears averaged 14.5 cm2, with 15.6 cm2 in men and 12.6 cm2 in women. The amount of skin deficiency was 25.4 cm2, with 26.7 cm2 in men and 23.1 cm2 in women. Conclusions: This study proposes a novel method to provide quantitative data on the skin surface area of the healthy adult auricle and the amount of skin deficiency in microtia patients. We demonstrate that the microtia ear has less than 50% of skin available compared with healthy ears. Limited skin availability in microtia patients can lead to healing problems after auricular reconstruction and poses a significant challenge in the development of tissue-engineered cartilage implants. The results of this study could be used to evaluate outcomes and investigate new techniques with regard to tissue-engineered auricular constructs. PMID:28293505

Quantitation of peptides from non-invasive skin tapings using isotope dilution and tandem mass spectrometry.

PubMed

Reisdorph, Nichole; Armstrong, Michael; Powell, Roger; Quinn, Kevin; Legg, Kevin; Leung, Donald; Reisdorph, Rick

2018-05-01

Previous work from our laboratories utilized a novel skin taping method and mass spectrometry-based proteomics to discover clinical biomarkers of skin conditions; these included atopic dermatitis, Staphylococcus aureus colonization, and eczema herpeticum. While suitable for discovery purposes, semi-quantitative proteomics is generally time-consuming and expensive. Furthermore, depending on the method used, discovery-based proteomics can result in high variation and inadequate sensitivity to detect low abundant peptides. Therefore, we strove to develop a rapid, sensitive, and reproducible method to quantitate disease-related proteins from skin tapings. We utilized isotopically-labeled peptides and tandem mass spectrometry to obtain absolute quantitation values on 14 peptides from 7 proteins; these proteins had shown previous importance in skin disease. The method demonstrated good reproducibility, dynamic range, and linearity (R 2  > 0.993) when n = 3 standards were analyzed across 0.05-2.5 pmol. The method was used to determine if differences exist between skin proteins in a small group of atopic versus non-atopic individuals (n = 12). While only minimal differences were found, peptides were detected in all samples and exhibited good correlation between peptides for 5 of the 7 proteins (R 2  = 0.71-0.98). This method can be applied to larger cohorts to further establish the relationships of these proteins to skin disease. Copyright © 2017. Published by Elsevier B.V.

Quantitative characterization of mechanically indented in vivo human skin in adults and infants using optical coherence tomography

NASA Astrophysics Data System (ADS)

Huang, Pin-Chieh; Pande, Paritosh; Shelton, Ryan L.; Joa, Frank; Moore, Dave; Gillman, Elisa; Kidd, Kimberly; Nolan, Ryan M.; Odio, Mauricio; Carr, Andrew; Boppart, Stephen A.

2017-03-01

Influenced by both the intrinsic viscoelasticity of the tissue constituents and the time-evolved redistribution of fluid within the tissue, the biomechanical response of skin can reflect not only localized pathology but also systemic physiology of an individual. While clinical diagnosis of skin pathologies typically relies on visual inspection and manual palpation, a more objective and quantitative approach for tissue characterization is highly desirable. Optical coherence tomography (OCT) is an interferometry-based imaging modality that enables in vivo assessment of cross-sectional tissue morphology with micron-scale resolution, which surpasses those of most standard clinical imaging tools, such as ultrasound imaging and magnetic resonance imaging. This pilot study investigates the feasibility of characterizing the biomechanical response of in vivo human skin using OCT. OCT-based quantitative metrics were developed and demonstrated on the human subject data, where a significant difference between deformed and nondeformed skin was revealed. Additionally, the quantified postindentation recovery results revealed differences between aged (adult) and young (infant) skin. These suggest that OCT has the potential to quantitatively assess the mechanically perturbed skin as well as distinguish different physiological conditions of the skin, such as changes with age or disease.

Direct Measurements of Skin Friction

NASA Technical Reports Server (NTRS)

Dhawan, Satish

1953-01-01

A device has been developed to measure local skin friction on a flat plate by measuring the force exerted upon a very small movable part of the surface of the flat plate. These forces, which range from about 1 milligram to about 100 milligrams, are measured by means of a reactance device. The apparatus was first applied to measurements in the low-speed range, both for laminar and turbulent boundary layers. The measured skin-friction coefficients show excellent agreement with Blasius' and Von Karman's results. The device was then applied to high-speed subsonic flow and the turbulent-skin-friction coefficients were determined up to a Mach number of about 0.8. A few measurements in supersonic flow were also made. This paper describes the design and construction of the device and the results of the measurements.

Quantitative risk assessment for skin sensitization: Success or failure?

PubMed

Kimber, Ian; Gerberick, G Frank; Basketter, David A

2017-02-01

Skin sensitization is unique in the world of toxicology. There is a combination of reliable, validated predictive test methods for identification of skin sensitizing chemicals, a clearly documented and transparent approach to risk assessment, and effective feedback from dermatology clinics around the world delivering evidence of the success or failure of the hazard identification/risk assessment/management process. Recent epidemics of contact allergy, particularly to preservatives, have raised questions of whether the safety/risk assessment process is working in an optimal manner (or indeed is working at all!). This review has as its focus skin sensitization quantitative risk assessment (QRA). The core toxicological principles of QRA are reviewed, and evidence of use and misuse examined. What becomes clear is that skin sensitization QRA will only function adequately if two essential criteria are met. The first is that QRA is applied rigourously, and the second is that potential exposure to the sensitizing substance is assessed adequately. This conclusion will come as no surprise to any toxicologist who appreciates the basic premise that "risk = hazard x exposure". Accordingly, use of skin sensitization QRA is encouraged, not least because the essential feedback from dermatology clinics can be used as a tool to refine QRA in situations where this risk assessment tool has not been properly used. Copyright © 2016 Elsevier Inc. All rights reserved.

Pigmentary Markers in Danes – Associations with Quantitative Skin Colour, Nevi Count, Familial Atypical Multiple-Mole, and Melanoma Syndrome

PubMed Central

Johansen, Peter; Andersen, Jeppe Dyrberg; Madsen, Linnea Nørgård; Ullum, Henrik; Glud, Martin; Børsting, Claus; Gniadecki, Robert; Morling, Niels

2016-01-01

To investigate whether pigmentation genes involved in the melanogenic pathway (melanogenesis) contributed to melanoma predisposition, we compared pigmentary genetics with quantitative skin pigmentation measurements, the number of atypical nevi, the total nevus count, and the familial atypical multiple mole and melanoma (FAMMM) syndrome. We typed 32 pigmentary SNP markers and sequenced MC1R in 246 healthy individuals and 116 individuals attending periodic control for malignant melanoma development, 50 of which were diagnosed with FAMMM. It was observed that individuals with any two grouped MC1R variants (missense, NM_002386:c. 456C > A (p.TYR152*), or NM_002386:c.83_84insA (p.Asn29Glnfs*14) had significantly (p<0.001) lighter skin pigmentation of the upper-inner arm than those with none or one MC1R variant. We did not observe any significant association of the MC1R variants with constitutive pigmentation measured on the buttock area. We hypothesize that the effect of MC1R variants on arm pigmentation is primarily reflecting the inability to tan when subjected to UVR. A gender specific effect on skin pigmentation was also observed, and it was found that the skin pigmentation of females on average were darker than that of males (p<0.01). We conclude that MC1R variants are associated with quantitative skin colour in a lightly pigmented Danish population. We did not observe any association between any pigmentary marker and the FAMMM syndrome. We suggest that the genetics of FAMMM is not related to the genetics of the pigmentary pathway. PMID:26938746

Skin condition measurement by using multispectral imaging system (Conference Presentation)

NASA Astrophysics Data System (ADS)

Jung, Geunho; Kim, Sungchul; Kim, Jae Gwan

2017-02-01

There are a number of commercially available low level light therapy (LLLT) devices in a market, and face whitening or wrinkle reduction is one of targets in LLLT. The facial improvement could be known simply by visual observation of face, but it cannot provide either quantitative data or recognize a subtle change. Clinical diagnostic instruments such as mexameter can provide a quantitative data, but it costs too high for home users. Therefore, we designed a low cost multi-spectral imaging device by adding additional LEDs (470nm, 640nm, white LED, 905nm) to a commercial USB microscope which has two LEDs (395nm, 940nm) as light sources. Among various LLLT skin treatments, we focused on getting melanin and wrinkle information. For melanin index measurements, multi-spectral images of nevus were acquired and melanin index values from color image (conventional method) and from multi-spectral images were compared. The results showed that multi-spectral analysis of melanin index can visualize nevus with a different depth and concentration. A cross section of wrinkle on skin resembles a wedge which can be a source of high frequency components when the skin image is Fourier transformed into a spatial frequency domain map. In that case, the entropy value of the spatial frequency map can represent the frequency distribution which is related with the amount and thickness of wrinkle. Entropy values from multi-spectral images can potentially separate the percentage of thin and shallow wrinkle from thick and deep wrinkle. From the results, we found that this low cost multi-spectral imaging system could be beneficial for home users of LLLT by providing the treatment efficacy in a quantitative way.

Genomic ancestry, self-reported "color" and quantitative measures of skin pigmentation in Brazilian admixed siblings.

PubMed

Leite, Tailce K M; Fonseca, Rômulo M C; de França, Nanci M; Parra, Esteban J; Pereira, Rinaldo W

2011-01-01

A current concern in genetic epidemiology studies in admixed populations is that population stratification can lead to spurious results. The Brazilian census classifies individuals according to self-reported "color", but several studies have demonstrated that stratifying according to "color" is not a useful strategy to control for population structure, due to the dissociation between self-reported "color" and genomic ancestry. We report the results of a study in a group of Brazilian siblings in which we measured skin pigmentation using a reflectometer, and estimated genomic ancestry using 21 Ancestry Informative Markers (AIMs). Self-reported "color", according to the Brazilian census, was also available for each participant. This made it possible to evaluate the relationship between self-reported "color" and skin pigmentation, self-reported "color" and genomic ancestry, and skin pigmentation and genomic ancestry. We observed that, although there were significant differences between the three "color" groups in genomic ancestry and skin pigmentation, there was considerable dispersion within each group and substantial overlap between groups. We also saw that there was no good agreement between the "color" categories reported by each member of the sibling pair: 30 out of 86 sibling pairs reported different "color", and in some cases, the sibling reporting the darker "color" category had lighter skin pigmentation. Socioeconomic status was significantly associated with self-reported "color" and genomic ancestry in this sample. This and other studies show that subjective classifications based on self-reported "color", such as the one that is used in the Brazilian census, are inadequate to describe the population structure present in recently admixed populations. Finally, we observed that one of the AIMs included in the panel (rs1426654), which is located in the known pigmentation gene SLC24A5, was strongly associated with skin pigmentation in this sample.

Retrieval of optical properties of skin from measurement and modeling the diffuse reflectance

NASA Astrophysics Data System (ADS)

Douven, Lucien F. A.; Lucassen, Gerald W.

2000-06-01

We present results on the retrieval of skin optical properties obtained by fitting of measurements of the diffuse reflectance of human skin. Reflectance spectra are simulated using an analytical model based on the diffusion approximation. This model is implemented in a simplex fit routine. The skin optical model used consists of five layers representing epidermis, capillary blood plexus, dermis, deep blood plexus and hypodermis. The optical properties of each layer are assumed homogeneously distributed. The main optical absorbers included are melanin in epidermis and blood. The experimental setup consists of a HP photospectrometer equipped with a remote fiber head. Total reflectance spectra were measured in the 400 - 820 nm wavelength range on the volar underarm of 19 volunteers under various conditions influencing the blood content and oxygenation degree. Changes in the reflectance spectra were observed. Using the fit routine changes in blood content in the capillary blood plexus and in the deep blood plexus could be quantified. These showed different influences on the total reflectance. The method can be helpful to quantitatively assess changes in skin color appearance such as occurs in the treatment of port wine stains, blanching, skin irritation and tanning.

Depigmented skin and phantom color measurements for realistic prostheses.

PubMed

Tanner, Paul; Leachman, Sancy; Boucher, Kenneth; Ozçelik, Tunçer Burak

2014-02-01

The purpose of this study was to test the hypothesis that regardless of human skin phototype, areas of depigmented skin, as seen in vitiligo, are optically indistinguishable among skin phototypes. The average of the depigmented skin measurements can be used to develop the base color of realistic prostheses. Data was analyzed from 20 of 32 recruited vitiligo study participants. Diffuse reflectance spectroscopy measurements were made from depigmented skin and adjacent pigmented skin, then compared with 66 pigmented polydimethylsiloxane phantoms to determine pigment concentrations in turbid media for making realistic facial prostheses. The Area Under spectral intensity Curve (AUC) was calculated for average spectroscopy measurements of pigmented sites in relation to skin phototype (P = 0.0505) and depigmented skin in relation to skin phototype (P = 0.59). No significant relationship exists between skin phototypes and depigmented skin spectroscopy measurements. The average of the depigmented skin measurements (AUC 19,129) was the closest match to phantom 6.4 (AUC 19,162). Areas of depigmented skin are visibly indistinguishable per skin phototype, yet spectrometry shows that depigmented skin measurements varied and were unrelated to skin phototype. Possible sources of optical variation of depigmented skin include age, body site, blood flow, quantity/quality of collagen, and other chromophores. The average of all depigmented skin measurements can be used to derive the pigment composition and concentration for realistic facial prostheses. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Development of a quantitative assessment method of pigmentary skin disease using ultraviolet optical imaging.

PubMed

Lee, Onseok; Park, Sunup; Kim, Jaeyoung; Oh, Chilhwan

2017-11-01

The visual scoring method has been used as a subjective evaluation of pigmentary skin disorders. Severity of pigmentary skin disease, especially melasma, is evaluated using a visual scoring method, the MASI (melasma area severity index). This study differentiates between epidermal and dermal pigmented disease. The study was undertaken to determine methods to quantitatively measure the severity of pigmentary skin disorders under ultraviolet illumination. The optical imaging system consists of illumination (white LED, UV-A lamp) and image acquisition (DSLR camera, air cooling CMOS CCD camera). Each camera is equipped with a polarizing filter to remove glare. To analyze images of visible and UV light, images are divided into frontal, cheek, and chin regions of melasma patients. Each image must undergo image processing. To reduce the curvature error in facial contours, a gradient mask is used. The new method of segmentation of front and lateral facial images is more objective for face-area-measurement than the MASI score. Image analysis of darkness and homogeneity is adequate to quantify the conventional MASI score. Under visible light, active lesion margins appear in both epidermal and dermal melanin, whereas melanin is found in the epidermis under UV light. This study objectively analyzes severity of melasma and attempts to develop new methods of image analysis with ultraviolet optical imaging equipment. Based on the results of this study, our optical imaging system could be used as a valuable tool to assess the severity of pigmentary skin disease. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Galvanic skin response measurement device. 882... Galvanic skin response measurement device. (a) Identification. A galvanic skin response measurement device... electrical resistance of the skin and the tissue path between two electrodes applied to the skin. (b...

Self-reported skin colour and erythemal sensitivity vs. objectively measured constitutive skin colour in an African population with predominantly dark skin.

PubMed

Wright, Caradee Y; Wilkes, Marcus; du Plessis, Johan L; Reeder, Anthony I

2015-11-01

Skin colour is an important factor in skin-related diseases. Accurate determination of skin colour is important for disease prevention and supporting healthy sun behaviour, yet such data are lacking for dark skin types. Self-perceived, natural skin colour and sun-skin reaction were compared with objectively measured skin colour among an African population with predominantly dark skin. Unexposed skin of 556 adults (70.1% Black) was measured with a reflectance spectrophotometer to calculate an individual typology angle (°ITA). Participants reported self-perceived skin colour and erythemal sensitivity. There was a strong, positive monotonic correlation between self-reported and measured skin colour (Spearman ρ = 0.6438, P < 0.001), but only a weak correlation between self-reported erythemal sensitivity and measured skin colour (Spearman ρ = 0.2713, P < 0.001). Self-report biases in underestimation and overestimation of skin colour were evident. Many participants with 'dark brown' and 'black' skin had difficulty in classifying erythemal sensitivity. In Africa, self-reported skin colour could potentially be used in lieu of spectrophotometer measurements, but options for questions on sunburn and tanning require suitable adjustment. Our study provides evidence of range in °ITA values among residents in Africa and reinforces previous results that self-report may be reliable for determining skin colour, but not erythemal sensitivity, for dark skin individuals. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Global Skin-Friction Measurements Using Particle Image Surface FLow Visualization and a Luminescent Oil-Film

NASA Technical Reports Server (NTRS)

Husen, Nicholas; Roozeboom, Nettie; Liu, Tianshu; Sullivan, John P.

2015-01-01

A quantitative global skin-friction measurement technique is proposed. An oil-film is doped with a luminescent molecule and thereby made to fluoresce in order to resolve oil-film thickness, and Particle Image Surface Flow Visualization is used to resolve the velocity field of the surface of the oil-film. Skin-friction is then calculated at location x as (x )xh, where x is the displacement of the surface of the oil-film and is the dynamic viscosity of the oil. The data collection procedure and data analysis procedures are explained, and preliminary experimental skin-friction results for flow over the wing of the CRM are presented.

21 CFR 882.1560 - Skin potential measurement device.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Skin potential measurement device. 882.1560... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1560 Skin potential measurement device. (a) Identification. A skin potential measurement device is a general diagnostic device...

21 CFR 882.1560 - Skin potential measurement device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Skin potential measurement device. 882.1560... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1560 Skin potential measurement device. (a) Identification. A skin potential measurement device is a general diagnostic device...

21 CFR 882.1560 - Skin potential measurement device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Skin potential measurement device. 882.1560... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1560 Skin potential measurement device. (a) Identification. A skin potential measurement device is a general diagnostic device...

21 CFR 882.1560 - Skin potential measurement device.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Skin potential measurement device. 882.1560... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1560 Skin potential measurement device. (a) Identification. A skin potential measurement device is a general diagnostic device...

Measuring niacin-associated skin toxicity (NASTy) stigmata along with symptoms to aid development of niacin mimetics[S

PubMed Central

Dunbar, Richard L.; Goel, Harsh; Tuteja, Sony; Song, Wen-Liang; Nathanson, Grace; Babar, Zeeshan; Lalic, Dusanka; Gelfand, Joel M.; Rader, Daniel J.; Grove, Gary L.

2017-01-01

Though cardioprotective, niacin monotherapy is limited by unpleasant cutaneous symptoms mimicking dermatitis: niacin-associated skin toxicity (NASTy). Niacin is prototypical of several emerging drugs suffering off-target rubefacient properties whereby agonizing the GPR109A receptor on cutaneous immune cells provokes vasodilation, prompting skin plethora and rubor, as well as dolor, tumor, and calor, and systemically, heat loss, frigor, chills, and rigors. Typically, NASTy effects are described by subjective patient-reported perception, at best semi-quantitative and bias-prone. Conversely, objective, quantitative, and unbiased methods measuring NASTy stigmata would facilitate research to abolish them, motivating development of several objective methods. In early drug development, such methods might better predict clinical tolerability in larger clinical trials. Measuring cutaneous stigmata may also aid investigations of vasospastic, ischemic, and inflammatory skin conditions. We present methods to measure NASTy physical stigmata to facilitate research into novel niacin mimetics/analogs, detailing characteristics of each technique following niacin, and how NASTy stigmata relate to symptom perception. We gave niacin orally and measured rubor by colorimetry and white-light spectroscopy, plethora by laser Doppler flowmetry, and calor/frigor by thermometry. Surprisingly, each stigma’s abruptness predicted symptom perception, whereas peak intensity did not. These methods are adaptable to study other rubefacient drugs or dermatologic and vascular disorders. PMID:28119443

Control of skin blood flow, sweating, and heart rate - Role of skin vs. core temperature

NASA Technical Reports Server (NTRS)

Wyss, C. R.; Brengelmann, G. L.; Johnson, J. M.; Rowell, L. B.; Niederberger, M.

1974-01-01

A study was conducted to generate quantitative expressions for the influence of core temperature, skin temperature, and the rate of change of skin temperature on sweat rate, skin blood flow, and heart rate. A second goal of the study was to determine whether the use of esophageal temperature rather than the right atrial temperature as a measure of core temperature would lead to different conclusions about the control of measured effector variables.

Genomic Ancestry, Self-Reported “Color” and Quantitative Measures of Skin Pigmentation in Brazilian Admixed Siblings

PubMed Central

Leite, Tailce K. M.; Fonseca, Rômulo M. C.; de França, Nanci M.; Parra, Esteban J.; Pereira, Rinaldo W.

2011-01-01

A current concern in genetic epidemiology studies in admixed populations is that population stratification can lead to spurious results. The Brazilian census classifies individuals according to self-reported “color”, but several studies have demonstrated that stratifying according to “color” is not a useful strategy to control for population structure, due to the dissociation between self-reported “color” and genomic ancestry. We report the results of a study in a group of Brazilian siblings in which we measured skin pigmentation using a reflectometer, and estimated genomic ancestry using 21 Ancestry Informative Markers (AIMs). Self-reported “color”, according to the Brazilian census, was also available for each participant. This made it possible to evaluate the relationship between self-reported “color” and skin pigmentation, self-reported “color” and genomic ancestry, and skin pigmentation and genomic ancestry. We observed that, although there were significant differences between the three “color” groups in genomic ancestry and skin pigmentation, there was considerable dispersion within each group and substantial overlap between groups. We also saw that there was no good agreement between the “color” categories reported by each member of the sibling pair: 30 out of 86 sibling pairs reported different “color”, and in some cases, the sibling reporting the darker “color” category had lighter skin pigmentation. Socioeconomic status was significantly associated with self-reported “color” and genomic ancestry in this sample. This and other studies show that subjective classifications based on self-reported “color”, such as the one that is used in the Brazilian census, are inadequate to describe the population structure present in recently admixed populations. Finally, we observed that one of the AIMs included in the panel (rs1426654), which is located in the known pigmentation gene SLC24A5, was strongly associated with

Skin-Friction Measurements in Incompressible Flow

NASA Technical Reports Server (NTRS)

Smith, Donald W.; Walker, John H.

1959-01-01

Experiments have been conducted to measure the local surface-shear stress and the average skin-friction coefficient in Incompressible flow for a turbulent boundary layer on a smooth flat plate having zero pressure gradient. Data were obtained for a range of Reynolds numbers from 1 million to 45 million. The local surface-shear stress was measured by a floating-element skin-friction balance and also by a calibrated total head tube located on the surface of the test wall. The average skin-friction coefficient was obtained from boundary-layer velocity profiles.

Quantitative Assessment of Skin Stiffness in Localized Scleroderma Using Ultrasound Shear-Wave Elastography.

PubMed

Wang, Liyun; Yan, Feng; Yang, Yujia; Xiang, Xi; Qiu, Li

2017-07-01

The purpose of this study was to evaluate the usefulness of ultrasound shear-wave elastography (US-SWE) in characterization of localized scleroderma (LS), as well as in the disease staging. A total of 21 patients with 37 LS lesions were enrolled in this study. The pathologic stage (edema, sclerosis or atrophy) of the lesions was characterized by pathologic examination. The skin elastic modulus (E-values including E mean , E min , E max and E sd ) and thickness (h) was evaluated both in LS lesions and site-matched unaffected skin (normal controls) using US-SWE. The relative difference of E-values (E RD ) was calculated between each pair of lesions and its normal control for comparison among different pathologic stages. Of the 37 LS lesions, 2 were in edema, 22 were in sclerosis and 13 were in atrophy. US-SWE results showed a significant increase of skin elastic modulus and thickness in all lesions (p < 0.001 in sclerosis and p < 0.05 in atrophy) compared with the normal controls. The measured skin elastic modulus and thickness were greater in sclerosis than in atrophy. However, once normalized by skin thickness, the atrophic lesions, which were on average thinner, appeared significantly stiffer than those of the sclerosis (normalized E RD : an increase of 316.3% in atrophy vs. 50.6% in sclerosis compared with the controls, p = 0.007). These findings suggest that US-SWE allows for quantitative evaluation of the skin stiffness of LS lesions in different stages; however, the E-values directly provided by the US-SWE system alone do not distinguish between the stages, and the normalization by skin thickness is necessary. This non-invasive, real-time imaging technique is an ideal tool for assessing and monitoring LS disease severity and progression. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Skin thickness effects on in vivo LXRF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preiss, I.L.; Washington, W. II

The analysis of lead concentration in bone utilizing LXRF can be adversely effected by overlying issue. A quantitative measure of the attenuation of the 10.5 keV Pb L a x-ray signal by skin and skin equivalent plastic has been conducted. Concentration ranges in plaster of Paris and goat bone from 7 to 90 ppm with attenuators of Lucite{reg_sign} and pig skin were examined. It is concluded that no quantitative or semi quantitative analysis can be achieved if overlying sue thickness exceeds 3 mm for Ph concentrations of less than 30 porn Ph in bone.

Quantitative relationship between the local lymph node assay and human skin sensitization assays.

PubMed

Schneider, K; Akkan, Z

2004-06-01

The local lymph node assay (LLNA) is a new test method which allows for the quantitative assessment of sensitizing potency in the mouse. Here, we investigate the quantitative correlation between results from the LLNA and two human sensitization tests--specifically, human repeat insult patch tests (HRIPTs) and human maximization tests (HMTs). Data for 57 substances were evaluated, of which 46 showed skin sensitizing properties in human tests, whereas 11 yielded negative results in humans. For better comparability data from mouse and human tests were transformed to applied doses per skin area, which ranged over four orders of magnitude for the substances considered. Regression analysis for the 46 human sensitizing substances revealed a significant positive correlation between the LLNA and human tests. The correlation was better between LLNA and HRIPT data (n=23; r=0.77) than between LLNA and HMT data (n=38; r=0.65). The observed scattering of data points is related to various uncertainties, in part associated with insufficiencies of data from older HMT studies. Predominantly negative results in the LLNA for another 11 substances which showed no skin sensitizing activity in human maximization tests further corroborate the correspondence between LLNA and human tests. Based on this analysis, the LLNA can be considered a reliable basis for relative potency assessments for skin sensitizers. Proposals are made for the regulatory exploitation of the LLNA: four potency groups can be established, and assignment of substances to these groups according to the outcome of the LLNA can be used to characterize skin sensitizing potency in substance-specific assessments. Moreover, based on these potency groups, a more adequate consideration of sensitizing substances in preparations becomes possible. It is proposed to replace the current single concentration limit for skin sensitizers in preparations, which leads to an all or nothing classification of a preparation as sensitizing to

High sensitivity optical measurement of skin gloss

PubMed Central

Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F.; Urbach, H. Paul; Varghese, Babu

2017-01-01

We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the improved sensitivity of the two proposed methods using Monte Carlo simulations and experiments performed on ISO gloss calibration standards with an optical prototype. The performance and linearity of the method was compared with different professional gloss measurement devices based on the ratio of specular to diffuse intensity. We demonstrate the feasibility for in-vivo skin gloss measurements by quantifying the temporal evolution of skin gloss after application of standard paraffin cream bases on skin. The presented method opens new possibilities in the fields of cosmetology and dermatopharmacology for measuring the skin gloss and resorption kinetics and the pharmacodynamics of various external agents. PMID:29026683

High sensitivity optical measurement of skin gloss.

PubMed

Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F; Urbach, H Paul; Varghese, Babu

2017-09-01

We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the improved sensitivity of the two proposed methods using Monte Carlo simulations and experiments performed on ISO gloss calibration standards with an optical prototype. The performance and linearity of the method was compared with different professional gloss measurement devices based on the ratio of specular to diffuse intensity. We demonstrate the feasibility for in-vivo skin gloss measurements by quantifying the temporal evolution of skin gloss after application of standard paraffin cream bases on skin. The presented method opens new possibilities in the fields of cosmetology and dermatopharmacology for measuring the skin gloss and resorption kinetics and the pharmacodynamics of various external agents.

Point-spread imaging for measurement of skin translucency and scattering.

PubMed

Jiang, Zhi-xing; Kaplan, Peter D

2008-08-01

The translucency of skin has long been identified as an important cue for healthy and youthful looking skin. There is currently no universal definition for skin translucency let alone a measurement method. We propose that skin translucency is the light scattering beneath skin surface. We demonstrate the use of polarization gated point spreading imaging for non-invasive, in vivo measurement of the translucency and the reduced scattering coefficient m's of skin. We developed a polarization-gated point-spread imaging system to measure the spread of the incident pencil-thin laser beam on the skin. Skin translucency was calculated as the spread of the laser beam. From the measurement of the shift of the light diffuse center from the light injection point, the reduced scattering coefficient m's of the skin was calculated. We validated the measurement technique with milk as an in vitro model for skin. The measured m's of milk solution was found to be linearly proportional to the milk concentration, in agreement with Beer's law. The calculated translucency decreased as the milk concentration increased or as the reduced scattering coefficient m's increased. It was also found that the translucency decreased as the absorption coefficient of the milk solution increased. The measured translucency of a set of custom made clay tiles correlated well with the consumer perception of the incremental ranking of the translucency. In vivo measurement of skin translucency and the reduced scattering coefficient m's were carried out on several volunteers. The measured reduced scattering coefficient m's was in agreement with those in the literature. The measured skin translucency for different skin ethnicities of Caucasian, North Asian, South Asian and African American were in line with the expectation that skin translucency decreases as the skin color gets darker.

Automatic measurement of skin textures of the dorsal hand in evaluating skin aging.

PubMed

Gao, Qian; Yu, Jiaming; Wang, Fang; Ge, Tiantian; Hu, Liwen; Liu, Yang

2013-05-01

Changes in skin textures have been used to evaluate skin aging in many studies. In our previous study, we built some skin texture parameters, which can be used to evaluate skin aging of human dorsal hand. However, it will take too much time and need to work arduously to get the information from digital skin image by manual work. So, we want to build a simple and effective method to automatically count some of those skin texture parameters by using digital image-processing technology. A total of 100 subjects aged 30 years and above were involved. Sun exposure history and demographic information were collected by using a questionnaire. The skin image of subjects' dorsal hand was obtained by using a portable skin detector. The number of grids, which is one of skin texture parameters built in our previous study, was measured manually and automatically. Automated image analysis program was developed by using Matlab 7.1 software. The number of grids counted automatically (NGA) was significantly correlated with the number of grids counted manually (NGM) (r = 0.9287, P < 0.0001). And in each age group, there were no significant differences between NGA and NGM. The NGA was negatively correlated with age and lifetime sun exposure, and decreased with increasing Beagley-Gibson score from 3 to 6. In addition, even after adjusting for NGA, the standard deviation of grid areas for each image was positively correlated with age, sun exposure, and Bealey-Gibson score. The method introduced in present study can be used to measure some skin aging parameters automatically and objectively. And it will save much time, reduce labor, and avoid measurement errors of deferent investigators when evaluating a great deal of skin images in a short time. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Measurement of erythema and tanning responses in human skin using a tri-stimulus colorimeter.

PubMed

Seitz, J C; Whitmore, C G

1988-01-01

A 'Minolta Tri-Stimulus Colorimeter II' was evaluated for obtaining objective measurements of early changes in erythema and tanning. The meter showed a subtle, continuous transition between the primary erythematous response and the delayed tanning of skin which was below the visual threshold for detection. Thereafter, the a* (redness) value of the meter showed a significant linear correlation with the dermatologist's perception of erythema while the b* (yellow) value showed a significant correlation with the perception of tanning. This capability of the tri-stimulus colorimeter to simultaneously evaluate the hue and saturation of skin color affords an improved opportunity to quantitate the transition from erythema to tanning without subjective bias.

In vitro fluorescence measurements and Monte Carlo simulation of laser irradiation propagation in porcine skin tissue.

PubMed

Drakaki, E; Makropoulou, M; Serafetinides, A A

2008-07-01

In dermatology, the in vivo spectral fluorescence measurements of human skin can serve as a valuable supplement to standard non-invasive techniques for diagnosing various skin diseases. However, quantitative analysis of the fluorescence spectra is complicated by the fact that skin is a complex multi-layered and inhomogeneous organ, with varied optical properties and biophysical characteristics. In this work, we recorded, in vitro, the laser-induced fluorescence emission signals of healthy porcine skin, one of the animals, which is considered as one of the most common models for investigations related to medical diagnostics of human cutaneous tissues. Differences were observed in the form and intensity of the fluorescence signal of the porcine skin, which can be attributed to the different concentrations of the native fluorophores and the variable physical and biological conditions of the skin tissue. As the light transport in the tissue target is directly influencing the absorption and the fluorescence emission signals, we performed Monte Carlo simulation of the light distribution in a five-layer model of human skin tissue, with a pulsed ultraviolet laser beam.

Comparing Alternative Methods of Measuring Skin Color and Damage

PubMed Central

Daniel, Lauren C.; Heckman, Carolyn J.; Kloss, Jacqueline D.; Manne, Sharon L.

2009-01-01

Objective: The current study investigated the reliability and validity of several skin color and damage measurement strategies and explored their applicability among participants of different races, skin types, and sexes. Methods: One hundred college-aged participants completed an online survey about their perceived skin damage and skin protection. They also attended an in-person session in which an observer rated their skin color; additionally, UV photos and spectrophotometry readings were taken. Results: Trained research assistants rated the damage depicted in the UV photos reliably. Moderate to high correlations emerged between skin color self-report and spectrophotometry readings. Observer rating correlated with spectrophotometry rating of current but not natural skin color. Lighter-skinned individuals reported more cumulative skin damage, which was supported by UV photography. Although women's current skin color was lighter and their UV photos showed similar damage to men's, women reported significantly more damaged skin than men did. Conclusions: These findings suggest that self-report continues to be a valuable measurement strategy when skin reflectance measurement is not feasible or appropriate and that UV photos and observer ratings may be useful but need to be tested further. The results also suggest that young women and men may benefit from different types of skin cancer prevention interventions. PMID:18931926

Softness sensor system for simultaneously measuring the mechanical properties of superficial skin layer and whole skin.

PubMed

Nakatani, Masashi; Fukuda, Toru; Arakawa, Naomi; Kawasoe, Tomoyuki; Omata, Sadao

2013-02-01

Few attempts have been made to distinguish the softness of different skin layers, though specific measurement of the superficial layer would be useful for evaluating the emollient effect of cosmetics and for diagnosis of skin diseases. We developed a sensor probe consisting of a piezoelectric tactile sensor and a load cell. To evaluate it, we firstly measured silicone rubber samples with different softness. Then, it was applied to human forearm skin before and after tape-stripping. A VapoMeter and skin-surface hygrometer were used to confirm removal of the stratum corneum. A Cutometer was used to obtain conventional softness data for comparison. Both the piezoelectric tactile sensor and the load cell could measure the softness of silicone rubber samples, but the piezoelectric tactile sensor was more sensitive than the load cell when the reaction force of the measured sample was under 100 mN in response to a 2-mm indentation. For human skin in vivo, transepidermal water loss and skin conductance were significantly changed after tape-stripping, confirming removal of the stratum corneum. The piezoelectric tactile sensor detected a significant change after tape-stripping, whereas the load cell did not. Thus, the piezoelectric tactile sensor can detect changes of mechanical properties at the skin surface. The load cell data were in agreement with Cutometer measurements, which showed no change in representative skin elasticity parameters after tape-stripping. These results indicate that our sensor can simultaneously measure the mechanical properties of the superficial skin layer and whole skin. © 2012 John Wiley & Sons A/S.

A novel method for real-time skin impedance measurement during radiofrequency skin tightening treatments.

PubMed

Harth, Yoram; Lischinsky, Daniel

2011-03-01

The thermal effects of monopolar and bipolar radiofrequency (RF) have been proven to be beneficial in skin tightening. Nevertheless, these effects were frequently partial or unpredictable because of the uncontrolled nature of monopolar or unipolar RF and the superficial nature of energy flow for bipolar or tripolar configurations. One of the hypotheses for lack or predictability of efficacy of the first-generation RF therapy skin tightening systems is lack of adaptation of delivered power to differences in individual skin impedance. A novel multisource phase-controlled system was used (1 MHz, power range 0-65 W) for treatment and real-time skin impedance measurements in 24 patients (EndyMed PRO™; EndyMed, Cesarea, Israel). This system allows continuous real-time measurement of skin impedance delivering constant energy to the patient skin independent of changes in its impedance. More than 6000 unique skin impedance measurements on 22 patients showed an average session impedance range was 215-584 Ohm with an average of 369 Ohm (standard deviation of 49 Ohm). Analyzing individual pulses (total of 600 readings) showed a significant decrease in impedance during the pulse. These findings validate the expected differences in skin impedance between individual patients and in the same patients during the treatment pulse. Clinical study on 30 patients with facial skin aging using the device has shown high predictability of efficacy (86.7% of patients had good results or better at 3 months' follow-up [decrease of 2 or more grades in Fitzpatrick's wrinkle scale]). The real-time customization of energy according to skin impedance allows a significantly more accurate and safe method of nonablative skin tightening with more consistent and predictable results. © 2011 Wiley Periodicals, Inc.

In-vivo Reflectance Measurements from Human Skin

NASA Astrophysics Data System (ADS)

Delgado, J. A.; Cornejo, A.; Cunill, M.; Báez, J. J.; Matos, R.; Anasagasti, L.; Santiago, C.

2006-09-01

We evaluate the potential of using a standard commercial spectrophotometer, specifically designed to meet the growing requirement for color control in the digital-imaging application field, to perform in-vivo diffuse reflectance measurements from adult human skin. We report and discuss diffuse reflectance spectra for three practical situations: a) reflectance versus skin type, b) reflectance from normal skin with different grade of solar exposition, c) reflectance from normal skin versus reflectance from seborrheic keratosis. Results show, that using the above spectrophotometer we can easily differentiate two sites of different solar exposition. Besides, significant differences are found in the normal skin diffuse reflectance for patients with different skin types.

Advanced haptic sensor for measuring human skin conditions

NASA Astrophysics Data System (ADS)

Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

2009-12-01

This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

Advanced haptic sensor for measuring human skin conditions

NASA Astrophysics Data System (ADS)

Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

2010-01-01

This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

A handheld optical device for skin profile measurement

NASA Astrophysics Data System (ADS)

Sun, Jiuai; Liu, Xiaojin

2018-04-01

This paper describes a portable optical scanning device designed for skin surface measurement on both colour and 3D geometry through a relative easy and cost effective multiple light source photometric stereo method. The validation of colour recovered had been verified through its application on skin lesion segmentation in our early work. This paper focuses on the reconstructed topographic data which are subject to further evaluation and advancement. The evaluation work takes the skin in vitro as an application scenario and compares the experimental result to that obtained by using a commercial product. The experiments show that this handheld device can measure the skin profile significantly closer to that of the ground truth and have the additional function of skin colour recovery.

Multimode optical dermoscopy (SkinSpect) analysis for skin with melanocytic nevus

NASA Astrophysics Data System (ADS)

Vasefi, Fartash; MacKinnon, Nicholas; Saager, Rolf; Kelly, Kristen M.; Maly, Tyler; Chave, Robert; Booth, Nicholas; Durkin, Anthony J.; Farkas, Daniel L.

2016-04-01

We have developed a multimode dermoscope (SkinSpect™) capable of illuminating human skin samples in-vivo with spectrally-programmable linearly-polarized light at 33 wavelengths between 468nm and 857 nm. Diffusely reflected photons are separated into collinear and cross-polarized image paths and images captured for each illumination wavelength. In vivo human skin nevi (N = 20) were evaluated with the multimode dermoscope and melanin and hemoglobin concentrations were compared with Spatially Modulated Quantitative Spectroscopy (SMoQS) measurements. Both systems show low correlation between their melanin and hemoglobin concentrations, demonstrating the ability of the SkinSpect™ to separate these molecular signatures and thus act as a biologically plausible device capable of early onset melanoma detection.

Noninvasive measurement of advanced glycation end-products in the facial skin: New data for skin aging studies.

PubMed

Qu, Di; Venzon, Dawna; Murray, Mary; Depauw, Mathew

Using skin autofluorescence (SAF) as a marker of advanced glycation end-products (AGEs) has been extensively studied in the last decade since the introduction of the noninvasive in vivo measurement technique. Data have shown the level of skin AGEs increases with chronological age in healthy human beings, and this increase is substantially higher in age-matched diabetic patients. In skin research, glycation with the accompanying accumulation of skin AGEs has been regarded as one of the primary skin aging mechanisms that contribute to skin wrinkling and the loss of skin elasticity. To date, the totality of SAF data reported in literature has been obtained from measurements on the arm, and noninvasive measurement of facial skin AGE accumulation would add great value to skin aging research. In this study, we report the levels of facial and forearm skin AGEs in 239 men and women of 21-65 year of age. Significantly lower levels of AGEs were detected in the facial skin than in the forearm skin from the young Caucasian groups, and the difference was much larger for men than for women. The rate of change in skin AGE level over age was found to be about 50% higher in men than in women, which further highlights the gender difference. A statistically significant correlation between the levels of skin AGE and facial wrinkling was also observed. The facial skin AGE data may provide new insight into skin aging research.

A quantitative and non-contact technique to characterise microstructural variations of skin tissues during photo-damaging process based on Mueller matrix polarimetry.

PubMed

Dong, Yang; He, Honghui; Sheng, Wei; Wu, Jian; Ma, Hui

2017-10-31

Skin tissue consists of collagen and elastic fibres, which are highly susceptible to damage when exposed to ultraviolet radiation (UVR), leading to skin aging and cancer. However, a lack of non-invasive detection methods makes determining the degree of UVR damage to skin in real time difficult. As one of the fundamental features of light, polarization can be used to develop imaging techniques capable of providing structural information about tissues. In particular, Mueller matrix polarimetry is suitable for detecting changes in collagen and elastic fibres. Here, we demonstrate a novel, quantitative, non-contact and in situ technique based on Mueller matrix polarimetry for monitoring the microstructural changes of skin tissues during UVR-induced photo-damaging. We measured the Mueller matrices of nude mouse skin samples, then analysed the transformed parameters to characterise microstructural changes during the skin photo-damaging and self-repairing processes. Comparisons between samples with and without the application of a sunscreen showed that the Mueller matrix-derived parameters are potential indicators for fibrous microstructure in skin tissues. Histological examination and Monte Carlo simulations confirmed the relationship between the Mueller matrix parameters and changes to fibrous structures. This technique paves the way for non-contact evaluation of skin structure in cosmetics and dermatological health.

Intrinsic, solar and sunbed-induced skin aging measured in vivo by multiphoton laser tomography and biophysical methods.

PubMed

Koehler, Martin Johannes; Preller, Anja; Kindler, Nadja; Elsner, Peter; König, Karsten; Bückle, Rainer; Kaatz, Martin

2009-08-01

Skin aging is accelerated by extrinsic factors, particularly actinic damage. Over the last decades, both clinical and pathological differences between intrinsic and actinic aging have been characterized. In this work, we aimed at quantifying skin aging by non-invasive in vivo methods. Young healthy volunteers using indoor tanning facilities and aged people were compared with appropriate controls by measurements of skin elasticity with the Cutometer and the Reviscometer and by semi-quantitative evaluation of the dermal matrix composition by the multiphoton laser tomograph DermaInspect. We found differences between the sun-protected volar forearm and the dorsal side as well as between young and old test persons with all three methods. No significant differences were found between the skin of indoor-tanned test persons and control. Also, gender had no influence on the severity of skin aging. The most consistent results were obtained with the DermaInspect. The considerable inter-individual variation due to the cross-sectional design of the study may have disguised the factual skin damage caused by tanning beds.

Use of SkinFibrometer® to measure skin elasticity and its correlation with Cutometer® and DUB® Skinscanner.

PubMed

Kim, M A; Kim, E J; Lee, H K

2018-02-06

Skin elasticity is an important indicator of skin aging. The aim of this study was to demonstrate that the SkinFibrometer ® is appropriate for measuring skin biomechanical properties, and to correlate it with elasticity parameters measured using the Cutometer ® and with dermis structural properties measured using DUB ® Skinscanner. Twenty-one individuals participated in this study. The skin of the cheek, around the eye, and the volar forearm were evaluated. To analyze correlations of elasticity parameters, the induration value against the indenter pressure of SkinFibrometer ® and R, Q parameters of Cutometer ® were compared. Dermal echogenicity using DUB ® Skinscanner was compared with the induration value of SkinFibrometer ® . The younger age group showed more firm and elastic skin properties compared to the older age group, and the elasticity values of the volar forearm were significantly higher than those of the cheek and around the eye region. Even though the measuring principle is different, both SkinFibrometer ® and Cutometer ® demonstrated the same trends of skin elasticity differences according to age and anatomical regions. There were significant correlations between the induration value of SkinFibrometer ® , representing skin firmness, and R0, Q0 and R2, R5, R7, Q1, Q2 of Cutometer ® , which represent skin firmness and resilience, respectively (P < .01). In addition, dermal echogenicity positively correlated with skin firmness determined by SkinFibrometer ® (P < .01). We identified correlations between skin elasticity parameters evaluated by two different methods of suction and indentation, and demonstrated that the SkinFibrometer ® is an objective, non-invasive evaluation tool for skin stiffness and elasticity. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Skin-friction measurements by laser interferometry

NASA Technical Reports Server (NTRS)

Kim, K.-S.; Settles, G. S.

1989-01-01

The measurement of skin friction in rapidly distorted compressible flows is difficult, and very few reliable techniques are available. A recent development, the laser interferometer skin friction (LISF) meter, promises to be useful for this purpose. This technique interferometrically measures the time rate of thinning of an oil film applied to an aerodynamic surface. Under the proper conditions the wall shear stress may thus be found directly, without reference to flow properties. The applicability of the LISF meter to supersonic boundary layers is examined experimentally. Its accuracy and repeatability are assessed, and conditions required for its successful application are considered.

In vivo skin imaging for hydration and micro relief-measurement.

PubMed

Kardosova, Z; Hegyi, V

2013-01-01

We present the results of our work with device used for measurement of skin capacitance before and after application of moisturizing creams and results of experiment performed on cellulose filter papers soaked with different solvents. The measurements were performed by a device built on capacitance sensor, which provides an investigator with a capacitance image of the skin. The capacitance values are coded in a range of 256 gray levels then the skin hydration can be characterized using parameters derived from gray level histogram by specific software. The images obtained by device allow a highly precise observation of skin topography. Measuring of skin capacitance brings new, objective, reliable information about topographical, physical and chemical parameters of the skin. The study shows that there is a good correlation between the average grayscale values and skin hydration. In future works we need to complete more comparison studies, interpret the average grayscale values to skin hydration levels and use it for follow-up of dynamics of skin micro-relief and hydration changes (Fig. 6, Ref. 15).

Non-invasive, investigative methods in skin aging.

PubMed

Longo, C; Ciardo, S; Pellacani, G

2015-12-01

A precise and noninvasive quantification of aging is of outmost importance for in vivo assessment of the skin aging "stage", and thus acts to minimize it. Several bioengineering methods have been proposed to objectively, precisely, and non-invasively measure skin aging, and to detect early skin damage, that is sub-clinically observable. In this review we have described the most relevant methods that have emerged from recently introduced technologies, aiming at quantitatively assessing the effects of aging on the skin.

In vivo skin dose measurement in breast conformal radiotherapy.

PubMed

Soleymanifard, Shokouhozaman; Aledavood, Seyed Amir; Noghreiyan, Atefeh Vejdani; Ghorbani, Mahdi; Jamali, Farideh; Davenport, David

2016-01-01

Accurate skin dose assessment is necessary during breast radiotherapy to assure that the skin dose is below the tolerance level and is sufficient to prevent tumour recurrence. The aim of the current study is to measure the skin dose and to evaluate the geometrical/anatomical parameters that affect it. Forty patients were simulated by TIGRT treatment planning system and treated with two tangential fields of 6 MV photon beam. Wedge filters were used to homogenise dose distribution for 11 patients. Skin dose was measured by thermoluminescent dosimeters (TLD-100) and the effects of beam incident angle, thickness of irradiated region, and beam entry separation on the skin dose were analysed. Average skin dose in treatment course of 50 Gy to the clinical target volume (CTV) was 36.65 Gy. The corresponding dose values for patients who were treated with and without wedge filter were 35.65 and 37.20 Gy, respectively. It was determined that the beam angle affected the average skin dose while the thickness of the irradiated region and the beam entry separation did not affect dose. Since the skin dose measured in this study was lower than the amount required to prevent tumour recurrence, application of bolus material in part of the treatment course is suggested for post-mastectomy advanced breast radiotherapy. It is more important when wedge filters are applied to homogenize dose distribution.

Two-dimensional auto-correlation analysis and Fourier-transform analysis of second-harmonic-generation image for quantitative analysis of collagen fiber in human facial skin

NASA Astrophysics Data System (ADS)

Ogura, Yuki; Tanaka, Yuji; Hase, Eiji; Yamashita, Toyonobu; Yasui, Takeshi

2018-02-01

We compare two-dimensional auto-correlation (2D-AC) analysis and two-dimensional Fourier transform (2D-FT) for evaluation of age-dependent structural change of facial dermal collagen fibers caused by intrinsic aging and extrinsic photo-aging. The age-dependent structural change of collagen fibers for female subjects' cheek skin in their 20s, 40s, and 60s were more noticeably reflected in 2D-AC analysis than in 2D-FT analysis. Furthermore, 2D-AC analysis indicated significantly higher correlation with the skin elasticity measured by Cutometer® than 2D-AC analysis. 2D-AC analysis of SHG image has a high potential for quantitative evaluation of not only age-dependent structural change of collagen fibers but also skin elasticity.

High temperature skin friction measurement

NASA Technical Reports Server (NTRS)

Tcheng, Ping; Holmes, Harlan K.; Supplee, Frank H., Jr.

1989-01-01

Skin friction measurement in the NASA Langley hypersonic propulsion facility is described. The sensor configuration utilized an existing balance, modified to provide thermal isolation and an increased standoff distance. For test run times of about 20 sec and ambient-air cooling of the test section and balance, the modified balance performed satisfactorily, even when it was subjected to acoustic and structural vibration. The balance is an inertially balanced closed-loop servo system where the current to a moving-coil motor needed to restore or null the output from the position sensor is a measure of the force or skin friction tending to displace the moving element. The accuracy of the sensor is directly affected by the position sensor in the feedback loop, in this case a linear-variable differential transformer which has proven to be influenced by temperature gradients.

Elastic fibers in human skin: quantitation of elastic fibers by computerized digital image analyses and determination of elastin by radioimmunoassay of desmosine.

PubMed

Uitto, J; Paul, J L; Brockley, K; Pearce, R H; Clark, J G

1983-10-01

The elastic fibers in the skin and other organs can be affected in several disease processes. In this study, we have developed morphometric techniques that allow accurate quantitation of the elastic fibers in punch biopsy specimens of skin. In this procedure, the elastic fibers, visualized by elastin-specific stains, are examined through a camera unit attached to the microscope. The black and white images sensing various gray levels are then converted to binary images after selecting a threshold with an analog threshold selection device. The binary images are digitized and the data analyzed by a computer program designed to express the properties of the image, thus allowing determination of the volume fraction occupied by the elastic fibers. As an independent measure of the elastic fibers, alternate tissue sections were used for assay of desmosine, an elastin-specific cross-link compound, by a radioimmunoassay. The clinical applicability of the computerized morphometric analyses was tested by examining the elastic fibers in the skin of five patients with pseudoxanthoma elasticum or Buschke-Ollendorff syndrome. In the skin of 10 healthy control subjects, the elastic fibers occupied 2.1 +/- 1.1% (mean +/- SD) of the dermis. The volume fractions occupied by the elastic fibers in the lesions of pseudoxanthoma elasticum or Buschke-Ollendorff syndrome were increased as much as 6-fold, whereas the values in the unaffected areas of the skin in the same patients were within normal limits. A significant correlation between the volume fraction of elastic fibers, determined by computerized morphometric analyses, and the concentration of desmosine, quantitated by radioimmunoassay, was noted in the total material. These results demonstrate that computerized morphometric techniques are helpful in characterizing disease processes affecting skin. This methodology should also be applicable to other tissues that contain elastic fibers and that are affected in various heritable and

Large-scale human skin lipidomics by quantitative, high-throughput shotgun mass spectrometry.

PubMed

Sadowski, Tomasz; Klose, Christian; Gerl, Mathias J; Wójcik-Maciejewicz, Anna; Herzog, Ronny; Simons, Kai; Reich, Adam; Surma, Michal A

2017-03-07

The lipid composition of human skin is essential for its function; however the simultaneous quantification of a wide range of stratum corneum (SC) and sebaceous lipids is not trivial. We developed and validated a quantitative high-throughput shotgun mass spectrometry-based platform for lipid analysis of tape-stripped SC skin samples. It features coverage of 16 lipid classes; total quantification to the level of individual lipid molecules; high reproducibility and high-throughput capabilities. With this method we conducted a large lipidomic survey of 268 human SC samples, where we investigated the relationship between sampling depth and lipid composition, lipidome variability in samples from 14 different sampling sites on the human body and finally, we assessed the impact of age and sex on lipidome variability in 104 healthy subjects. We found sebaceous lipids to constitute an abundant component of the SC lipidome as they diffuse into the topmost SC layers forming a gradient. Lipidomic variability with respect to sampling depth, site and subject is considerable, and mainly accredited to sebaceous lipids, while stratum corneum lipids vary less. This stresses the importance of sampling design and the role of sebaceous lipids in skin studies.

Skin-friction measurements in high-enthalpy hypersonic boundary layers

NASA Astrophysics Data System (ADS)

Goyne, C. P.; Stalker, R. J.; Paull, A.

2003-06-01

Skin-friction measurements are reported for high-enthalpy and high-Mach-number laminar, transitional and turbulent boundary layers. The measurements were performed in a free-piston shock tunnel with air-flow Mach number, stagnation enthalpy and Reynolds numbers in the ranges of 4.4 6.7, 3 13 MJ kg(-1) and 0.16× 10(6) 21× 10(6) , respectively. Wall temperatures were near 300 K and this resulted in ratios of wall enthalpy to flow-stagnation enthalpy in the range of 0.1 0.02. The experiments were performed using rectangular ducts. The measurements were accomplished using a new skin-friction gauge that was developed for impulse facility testing. The gauge was an acceleration compensated piezoelectric transducer and had a lowest natural frequency near 40 kHz. Turbulent skin-friction levels were measured to within a typical uncertainty of ± 7%. The systematic uncertainty in measured skin-friction coefficient was high for the tested laminar conditions; however, to within experimental uncertainty, the skin-friction and heat-transfer measurements were in agreement with the laminar theory of van Driest (1952). For predicting turbulent skin-friction coefficient, it was established that, for the range of Mach numbers and Reynolds numbers of the experiments, with cold walls and boundary layers approaching the turbulent equilibrium state, the Spalding & Chi (1964) method was the most suitable of the theories tested. It was also established that if the heat transfer rate to the wall is to be predicted, then the Spalding & Chi (1964) method should be used in conjunction with a Reynolds analogy factor near unity. If more accurate results are required, then an experimentally observed relationship between the Reynolds analogy factor and the skin-friction coefficient may be applied.

MALDI imaging facilitates new topical drug development process by determining quantitative skin distribution profiles.

PubMed

Bonnel, David; Legouffe, Raphaël; Eriksson, André H; Mortensen, Rasmus W; Pamelard, Fabien; Stauber, Jonathan; Nielsen, Kim T

2018-04-01

Generation of skin distribution profiles and reliable determination of drug molecule concentration in the target region are crucial during the development process of topical products for treatment of skin diseases like psoriasis and atopic dermatitis. Imaging techniques like mass spectrometric imaging (MSI) offer sufficient spatial resolution to generate meaningful distribution profiles of a drug molecule across a skin section. In this study, we use matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to generate quantitative skin distribution profiles based on tissue extinction coefficient (TEC) determinations of four different molecules in cross sections of human skin explants after topical administration. The four drug molecules: roflumilast, tofacitinib, ruxolitinib, and LEO 29102 have different physicochemical properties. In addition, tofacitinib was administrated in two different formulations. The study reveals that with MALDI-MSI, we were able to observe differences in penetration profiles for both the four drug molecules and the two formulations and thereby demonstrate its applicability as a screening tool when developing a topical drug product. Furthermore, the study reveals that the sensitivity of the MALDI-MSI techniques appears to be inversely correlated to the drug molecules' ability to bind to the surrounding tissues, which can be estimated by their Log D values. Graphical abstract.

Skin sensitization quantitative risk assessment for occupational exposure of hairdressers to hair dye ingredients.

PubMed

Goebel, Carsten; Diepgen, Thomas L; Blömeke, Brunhilde; Gaspari, Anthony A; Schnuch, Axel; Fuchs, Anne; Schlotmann, Kordula; Krasteva, Maya; Kimber, Ian

2018-06-01

Occupational exposure of hairdressers to hair dyes has been associated with the development of allergic contact dermatitis (ACD) involving the hands. p-Phenylenediamine (PPD) and toluene-2,5-diamine (PTD) have been implicated as important occupational contact allergens. To conduct a quantitative risk assessment for the induction of contact sensitization to hair dyes in hairdressers, available data from hand rinsing studies following typical occupational exposure conditions to PPD, PTD and resorcinol were assessed. By accounting for wet work, uneven exposure and inter-individual variability for professionals, daily hand exposure concentrations were derived. Secondly, daily hand exposure was compared with the sensitization induction potency of the individual hair dye defined as the No Expected Sensitization Induction Levels (NESIL). For PPD and PTD hairdresser hand exposure levels were 2.7 and 5.9 fold below the individual NESIL. In contrast, hand exposure to resorcinol was 50 fold below the NESIL. Correspondingly, the risk assessment for PPD and PTD indicates that contact sensitization may occur, when skin protection and skin care are not rigorously applied. We conclude that awareness of health risks associated with occupational exposure to hair dyes, and of the importance of adequate protective measures, should be emphasized more fully during hairdresser education and training. Copyright © 2018 Elsevier Inc. All rights reserved.

Instrumentation for the measurement of autofluorescence in human skin

NASA Astrophysics Data System (ADS)

Graaff, Reindert; Meerwaldt, Robbert; Lutgers, Helen L.; Baptist, Rene; de Jong, Ed D.; Zijp, Jaap R.; Links, Thera P.; Smit, Andries J.; Rakhorst, Gerhard

2005-04-01

A setup to measure skin autofluorescence was developed to assess accumulation of advanced glycation endproducts (AGE) in patients noninvasively. The method applies direct blacklight tube illumination of the skin of the lower arm, and spectrometry. The setup displays skin autofluorescence (AF) as a ratio of mean intensities detected from the skin between 420-600 nm and 300-420 nm, respectively. In an early clinical application in 46 and control subjects matched for age and gender, AF was significantly increased in the patients (p = 0.015), and highly correlated with skin AGE's that were determined from skin biopsies in both groups. A large follow-up study on type 2 diabetes mellitus, ongoing since 2001 with more than 1000 subjects, aims to assess the value of the instrument in predicting chronic complications of diabetes. At baseline, a relation with age, glycemic status and with complications present was found. In a study in patients with end stage renal disease on dialysis AF was a strong and independent predictor of total and cardiovascular mortality. A commercial version of this AGE-reader is now under development and becomes available early 2005 (DiagnOptics B.V., Groningen, The Netherlands). One of the remaining questions, that will be answered by measuring so-called Exciation-Emission Matrices (EEM's) of the skin tissue in vivo, is whether a more selective choice of wavelengths is more strongly related to clinical characteristics. An experimental instrument to measure these EEM's was, therefore, developed as well. Clinical measurements are underway of EEM's in patient groups with diabetes mellitus and in healthy volunteers.

Technical note: comparing von Luschan skin color tiles and modern spectrophotometry for measuring human skin pigmentation.

PubMed

Swiatoniowski, Anna K; Quillen, Ellen E; Shriver, Mark D; Jablonski, Nina G

2013-06-01

Prior to the introduction of reflectance spectrophotometry into anthropological field research during the 1950s, human skin color was most commonly classified by visual skin color matching using the von Luschan tiles, a set of 36 standardized, opaque glass tiles arranged in a chromatic scale. Our goal was to establish a conversion formula between the tile-based color matching method and modern reflectance spectrophotometry to make historical and contemporary data comparable. Skin pigmentation measurements were taken on the forehead, inner upper arms, and backs of the hands using both the tiles and a spectrophotometer on 246 participants showing a broad range of skin pigmentation. From these data, a second-order polynomial conversion formula was derived by jackknife analysis to estimate melanin index (M-index) based on tile values. This conversion formula provides a means for comparing modern data to von Luschan tile measurements recorded in historical reports. This is particularly important for populations now extinct, extirpated, or admixed for which tile-based measures of skin pigmentation are the only data available. Copyright © 2013 Wiley Periodicals, Inc.

Facial skin color measurement based on camera colorimetric characterization

NASA Astrophysics Data System (ADS)

Yang, Boquan; Zhou, Changhe; Wang, Shaoqing; Fan, Xin; Li, Chao

2016-10-01

The objective measurement of facial skin color and its variance is of great significance as much information can be obtained from it. In this paper, we developed a new skin color measurement procedure which includes following parts: first, a new skin tone color checker made of pantone Skin Tone Color Checker was designed for camera colorimetric characterization; second, the chromaticity of light source was estimated via a new scene illumination estimation method considering several previous algorithms; third, chromatic adaption was used to convert the input facial image into output facial image which appears taken under canonical light; finally the validity and accuracy of our method was verified by comparing the results obtained by our procedure with these by spectrophotometer.

Measuring hemoglobin amount and oxygen saturation of skin with advancing age

NASA Astrophysics Data System (ADS)

Watanabe, Shumpei; Yamamoto, Satoshi; Yamauchi, Midori; Tsumura, Norimichi; Ogawa-Ochiai, Keiko; Akiba, Tetsuo

2012-03-01

We measured the oxygen saturation of skin at various ages using our previously proposed method that can rapidly simulate skin spectral reflectance with high accuracy. Oxygen saturation is commonly measured by a pulse oximeter to evaluate oxygen delivery for monitoring the functions of heart and lungs at a specific time. On the other hand, oxygen saturation of skin is expected to assess peripheral conditions. Our previously proposed method, the optical path-length matrix method (OPLM), is based on a Monte Carlo for multi-layered media (MCML), but can simulate skin spectral reflectance 27,000 times faster than MCML. In this study, we implemented an iterative simulation of OPLM with a nonlinear optimization technique such that this method can also be used for estimating hemoglobin concentration and oxygen saturation from the measured skin spectral reflectance. In the experiments, the skin reflectance spectra of 72 outpatients aged between 20 and 86 years were measured by a spectrophotometer. Three points were measured for each subject: the forearm, the thenar eminence, and the intermediate phalanx. The result showed that the oxygen saturation of skin remained constant at each point as the age varied.

Quantitative proteomics of the human skin secretome reveal a reduction in immune defense mediators in ectodermal dysplasia patients.

PubMed

Burian, Marc; Velic, Ana; Matic, Katarina; Günther, Stephanie; Kraft, Beatrice; Gonser, Lena; Forchhammer, Stephan; Tiffert, Yvonne; Naumer, Christian; Krohn, Michael; Berneburg, Mark; Yazdi, Amir S; Maček, Boris; Schittek, Birgit

2015-03-01

In healthy human skin host defense molecules such as antimicrobial peptides (AMPs) contribute to skin immune homeostasis. In patients with the congenital disease ectodermal dysplasia (ED) skin integrity is disturbed and as a result patients have recurrent skin infections. The disease is characterized by developmental abnormalities of ectodermal derivatives and absent or reduced sweating. We hypothesized that ED patients have a reduced skin immune defense because of the reduced ability to sweat. Therefore, we performed a label-free quantitative proteome analysis of wash solution of human skin from ED patients or healthy individuals. A clear-cut difference between both cohorts could be observed in cellular processes related to immunity and host defense. In line with the extensive underrepresentation of proteins of the immune system, dermcidin, a sweat-derived AMP, was reduced in its abundance in the skin secretome of ED patients. In contrast, proteins involved in metabolic/catabolic and biosynthetic processes were enriched in the skin secretome of ED patients. In summary, our proteome profiling provides insights into the actual situation of healthy versus diseased skin. The systematic reduction in immune system and defense-related proteins may contribute to the high susceptibility of ED patients to skin infections and altered skin colonization.

21 CFR 882.1560 - Skin potential measurement device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Skin potential measurement device. 882.1560 Section 882.1560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1560 Skin potential...

Skin Friction Measurements by a Dual-Laser-Beam Interferometer Technique

NASA Technical Reports Server (NTRS)

Monson, D. J.; Higuchi, H.

1981-01-01

A portable dual-laser-beam interferometer that nonintrusively measures skin friction by monitoring the thickness change of an oil film subject to shear stress is described. The method is an advance over past versions in that the troublesome and error-introducing need to measure the distance to the oil leading edge and the starting time for the oil flow has been eliminated. The validity of the method was verified by measuring oil viscosity in the laboratory, and then using those results to measure skin friction beneath the turbulent boundary layer in a low speed wind tunnel. The dual-laser-beam skin friction measurements are compared with Preston tube measurements, with mean velocity profile data in a "law-of-the-well" coordinate system, and with computations based on turbulent boundary-layer theory. Excellent agreement is found in all cases. (This validation and the aforementioned improvements appear to make the present form of the instrument usable to measure skin friction reliably and nonintrusively in a wide range of flow situations in which previous methods are not practical.)

GC-MS quantitation of fragrance compounds suspected to cause skin reactions. 1.

PubMed

Chaintreau, Alain; Joulain, Daniel; Marin, Christophe; Schmidt, Claus-Oliver; Vey, Matthias

2003-10-22

Recent changes in European legislation require monitoring of 24 volatile compounds in perfumes as they might elicit skin sensitization. This paper reports a GC-MS quantitation procedure for their determination in fragrance concentrates. GC and MS conditions were optimized for a routine use: analysis within 30 min, solvent and internal standard selection, and stock solution stability. Calibration curves were linear in the range of 2-100 mg/L with coefficients of determination in excess of 0.99. The method was tested using real perfumes spiked with known amounts of reference compounds.

Effectiveness of skin protection measures in prevention of occupational hand eczema: results of a prospective randomized controlled trial over a follow-up period of 1 year.

PubMed

Kütting, B; Baumeister, T; Weistenhöfer, W; Pfahlberg, A; Uter, W; Drexler, H

2010-02-01

We recently found a very low adherence to a generally recommended skin protection regimen in a sample of 1355 metalworkers. The present study assessed the effectiveness of skin protection as presently recommended, especially the differential contribution of skin care and skin protection, to the prevention of occupational hand eczema. Methods Of 1355 metalworkers screened, 1020 male volunteers, all fit for work, were recruited for a prospective intervention study with four arms (skin care, skin protection, both combined, and control group, i.e. no recommendation). The study was performed from winter 2006/2007 to spring 2008, following each subject for up for 12 months. Both hands were examined using a quantitative skin score, and a standardized personal interview was performed three times. The change of the objective skin score from baseline to 12 months was used as primary outcome measure. After 12 months 800 subjects were included (78.4% of those recruited). The compliance to follow the randomized measure depended on the recommended measure and ranged from 73.7% to 88.7%. While in the control group a significant deterioration was found, the largest and significant improvement was noted in the group following the generally recommended skin protection programme (skin care + skin protection) followed by skin protection alone as second best. The generally recommended skin protection regimen seems to provide effective prevention of occupational skin disease. Therefore, the compliance to follow the skin protection regimen, especially the use of skin protection, should be enhanced.

Local effect of compression stockings on skin microcirculatory activity through the measurement of skin effective thermal conductivity.

PubMed

Grenier, Etienne; Gehin, Claudine; Lun, Bertrand; McAdams, Eric

2013-01-01

This paper presents a preliminary study to demonstrate the instantaneous local effect of compression stocking (Class 2) on skin microcirculatory activity. The measurement needs to be carefully performed as the sensor is placed under the garment. To assess the local effect of compression stockings, we use the ambulatory device Hematron located on the calf under the garment. Skin microcirculatory activity is assessed through the skin's effective thermal conductivity measurement. A specific housing for the sensor has been designed to avoid excessive pressure induced by the sensor when squeezed by stockings. The experiment, conducted on ten healthy subjects, comprised two stages: without and with compression stockings. Skin effective thermal conductivity was recorded at three successive positions (supine, sitting and standing). Significant improvement in skin microcirculatory activity was recorded by the Hematron device for the three positions. We have also demonstrated that Hematron sensor can be used under compression stockings.

Quantitative Proteomic Profiling of Low Dose Ionizing Radiation Effects in a Human Skin Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hengel, Shawna; Aldrich, Joshua T.; Waters, Katrina M.

2014-07-29

To assess molecular responses to low doses of radiation that may be encountered during medical diagnostic procedures, nuclear accidents, or terrorist acts, a quantitative global proteomic approach was used to identify protein alterations in a reconstituted human skin tissue treated with 10 cGy of ionizing radiation. Subcellular fractionation was employed to remove highly abundant structural proteins and provide insight on radiation induced alterations in protein abundance and localization. In addition, peptides were post-fractionated using high resolution 2-dimensional liquid chromatography to increase the dynamic range of detection of protein abundance and translocation changes. Quantitative data was obtained by labeling peptides withmore » 8-plex isobaric iTRAQ tags. A total of 207 proteins were detected with statistically significant alterations in abundance and/or subcellular localization compared to sham irradiated tissues. Bioinformatics analysis of the data indicated that the top canonical pathways affected by low dose radiation are related to cellular metabolism. Among the proteins showing alterations in abundance, localization and proteolytic processing was the skin barrier protein filaggrin which is consistent with our previous observation that ionizing radiation alters profilaggrin processing with potential effects on skin barrier functions. In addition, a large number of proteases and protease regulators were affected by low dose radiation exposure indicating that altered proteolytic activity may be a hallmark of low dose radiation exposure. While several studies have demonstrated altered transcriptional regulation occurs following low dose radiation exposures, the data presented here indicates post-transcriptional regulation of protein abundance, localization, and proteolytic processing play an important role in regulating radiation responses in complex human tissues.« less

Skin Color and Pigmentation in Ethnic Skin.

PubMed

Visscher, Marty O

2017-02-01

Skin coloration is highly diverse, partly due to the presence of pigmentation. Color variation is related to the extent of ultraviolet radiation exposure, as well as other factors. Inherent skin coloration arises from differences in basal epidermal melanin amount and type. Skin color is influenced by both the quantity and distribution of melanocytes. The effectiveness of inherent pigmentation for protecting living cells also varies. This article discusses skin color, pigmentation, and ethnicity in relation to clinical practice. Color perception, skin typing/classification, and quantitation of pigmentation are reviewed in relation to ethnicity, environmental stresses/irritants, and potential treatment effects. Copyright © 2016 Elsevier Inc. All rights reserved.

An 8-channel skin impedance measurement system for acupuncture research.

PubMed

Thong, Tran; Colbert, Agatha P; Larsen, Adrian P

2009-01-01

An 8-channel skin impedance measurement system for acupuncture research has been developed. The underlying model of the skin used is a parallel R & C network. Pulses are used to measure the R and C values. The measurement circuit is time multiplexed across the 8 channels at the rate of 2 measurements per second, leading to a complete set of measurements every 4 seconds. In static tests, the system has been operational for over 2 days of continuous measurements. In preliminary human tests, measurements over 2 hours have been collected per subject.

In-Vivo Human Skin to Textiles Friction Measurements

NASA Astrophysics Data System (ADS)

Pfarr, Lukas; Zagar, Bernhard

2017-10-01

We report on a measurement system to determine highly reliable and accurate friction properties of textiles as needed for example as input to garment simulation software. Our investigations led to a set-up that allows to characterize not just textile to textile but also textile to in-vivo human skin tribological properties and thus to fundamental knowledge about genuine wearer interaction in garments. The method of test conveyed in this paper is measuring concurrently and in a highly time resolved manner the normal force as well as the resulting shear force caused by a friction subject intending to slide out of the static friction regime and into the dynamic regime on a test bench. Deeper analysis of various influences is enabled by extending the simple model following Coulomb's law for rigid body friction to include further essential parameters such as contact force, predominance in the yarn's orientation and also skin hydration. This easy-to-use system enables to measure reliably and reproducibly both static and dynamic friction for a variety of friction partners including human skin with all its variability there might be.

Objective measurements of excess skin in post bariatric patients--inter-rater reliability.

PubMed

Biörserud, Christina; Fagevik Olsén, Monika; Elander, Anna; Wiklund, Malin

2016-01-01

An ability to reliably assess excess skin after massive weight loss using well-described and transferrable methods is important. The aim of this trial was to evaluate inter-rater reliability of ptosis and circumference measurements in patients with excess skin after bariatric surgery. Twenty-five postbariatric patients were included in the study, and their excess skin was measured 18 months after surgery. A protocol was designed to measure excess skin in a standardised way. To evaluate the inter-rater reliability in the measuring protocol, all patients were measured twice, by a specialist nurse and a specialist physiotherapist. All circumference measurements on different body parts had an ICC > 0.9, indicating high reliability. Furthermore, all breast and abdominal ptosis measurements had high reliability. In contrast, visual evaluation of abdominal ptosis had poor reliability. Measurements of ptoses on different body parts had an ICC > 0.6. There were no systematic differences between the results of the two testers, except for measurements of the buttocks and maximal knee circumference. The measuring protocol presented in this study has high reliability and, therefore, represents a useful instrument to provide a consistent and objective assessment of excess skin in the postbariatric patient.

Measurement of lidocaine and 2,6-dimethylaniline in minipig plasma, skin, and dermal tapes using UHPLC with electrospray MS/MS.

PubMed

Li, Qian; Magers, Tobias; King, Brad; Engel, Brian J; Bakhtiar, Ray; Green, Charisse; Shoup, Ronald

2018-06-15

Sensitive LC-MS/MS methods were developed to measure lidocaine and its metabolite 2,6-dimethylaniline (2,6-DMA) with application to transdermal studies. The methods for lidocaine in minipig plasma, tissue biopsies, and dermal tapes utilized mixed mode/SCX solid phase extraction, with lower quantitation limits of 25 pg/mL in plasma, 15 ng/g tissue, and 5 ng/tape. 2,6-DMA was measured in plasma and skin tissue homogenates by ultrafiltration and (for tissue) by further derivatization with 4-methoxybenzoyl chloride to form the corresponding benzamide derivative, which extended the lower limit of quantitation to 200 pg/mL. The methods allowed local measurement of lidocaine in stratum corneum, punch biopsies, and plasma and of 2,6-DMA in plasma and biopsies obtained from minipigs dosed with experimental transdermal formulations. Quantitation limits were approximately 7-fold lower than previously reported for lidocaine and 3-fold lower for 2,6-DMA. Copyright © 2018 Elsevier B.V. All rights reserved.

Quantitative description of human skin water dynamics by a disposition-decomposition analysis (DDA) of trans-epidermal water loss and epidermal capacitance.

PubMed

Rodrigues, Luis Monteiro; Pinto, Pedro Contreiras; Pereira, Luis Marcelo

2003-02-01

In vivo water assessment would greatly benefit from a dynamical approach since the evaluation of common related variables such as trans-epidermal water loss or "capacitance" measurements is always limited to instantaneous data. Mathematical modelling is still an attractive alternative already attempted with bi-exponential empirical models. A classical two-compartment interpretation of such models raises a number of questions about the underlying fundamentals, which can hardly be experimentally confirmed. However, in a system analysis sense, skin water dynamics may be approached as an ensemble of many factors, impossible to discretize, but conceptually grouped in terms of feasible properties of the system. The present paper explores the applicability of this strategy to the in vivo water dynamics assessment. From the plastic occlusion stress test (POST) skin water balance is assessed by modelling trans-epidermal water loss (TEWL) and "capacitance" data obtained at skin's surface. With system analysis (disposition-decomposition analysis) the distribution function, H(t), modelled as a sum of exponential terms, covers only the distribution characteristics of water molecules traversing the skin. This may correspond macroscopically to the experimental data accessed by "corneometry". Separately, the hyperbolic elimination function Q(TEWL) helps to characterise the dynamic aspects of water influx through the skin. In the observable range there seems to be a linear relationship between the net amount of water lost at the surface by evaporation, and the capability of the system to replenish that loss. This may be a specific characteristic of the system related to what may be described as the skin's "intrinsic hydration capacity" (IHC) a new functional parameter only identified by this strategy. These new quantitative tools are expected to find different applicabilities (from the in vivo skin characterisation to efficacy testing) contributing to disclose the dynamical nature

Uncertainty Analysis for Oil-Film Interferometry Skin-Friction Measurement Techniques

NASA Technical Reports Server (NTRS)

Naughton, Jonathan W.; Brown, James L.; Merriam, Marshal (Technical Monitor)

1996-01-01

Over the past 20 years, the use of oil-film interferometry to measure the skin friction coefficient (C(sub f) = tau/q where tau is the surface shear stress and q is the dynamic pressure) has increased. Different forms of this oil-film technique with various levels of accuracy and ease of use have been successfully applied in a wide range of flows. The method's popularity is growing due to its relative ease of implementation and minimal intrusiveness as well as an increased demand for C(sub f) measurements. Nonetheless, the accuracy of these methods has not been rigorously addressed to date. Most researchers have simply shown that the skin-friction measurements made using these techniques compare favorably with other measurements and theory, most of which are only accurate to within 5-20%. The use of skin-friction data in the design of commercial aircraft, whose drag at cruise is 50% skin-friction drag, and in the validation of computational fluid dynamics programs warrants better uncertainty estimates. Additional information is contained in the original extended abstract.

Improved electrode paste provides reliable measurement of galvanic skin response

NASA Technical Reports Server (NTRS)

Day, J. L.

1966-01-01

High-conductivity electrode paste is used in obtaining accurate skin resistance or skin potential measurements. The paste is isotonic to perspiration, is nonirritating and nonsensitizing, and has an extended shelf life.

Skin Temperature Measurement Using Contact Thermometry: A Systematic Review of Setup Variables and Their Effects on Measured Values.

PubMed

MacRae, Braid A; Annaheim, Simon; Spengler, Christina M; Rossi, René M

2018-01-01

Background: Skin temperature ( T skin ) is commonly measured using T skin sensors affixed directly to the skin surface, although the influence of setup variables on the measured outcome requires clarification. Objectives: The two distinct objectives of this systematic review were (1) to examine measurements from contact T skin sensors considering equilibrium temperature and temperature disturbance, sensor attachments, pressure, environmental temperature, and sensor type, and (2) to characterise the contact T skin sensors used, conditions of use, and subsequent reporting in studies investigating sports, exercise, and other physical activity. Data sources and study selection: For the measurement comparison objective, Ovid Medline and Scopus were used (1960 to July 2016) and studies comparing contact T skin sensor measurements in vivo or using appropriate physical models were included. For the survey of use, Ovid Medline was used (2011 to July 2016) and studies using contact temperature sensors for the measurement of human T skin in vivo during sport, exercise, and other physical activity were included. Study appraisal and synthesis methods: For measurement comparisons, assessments of risk of bias were made according to an adapted version of the Cochrane Collaboration's risk of bias tool. Comparisons of temperature measurements were expressed, where possible, as mean difference and 95% limits of agreement (LoA). Meta-analyses were not performed due to the lack of a common reference condition. For the survey of use, extracted information was summarised in text and tabular form. Results: For measurement comparisons, 21 studies were included. Results from these studies indicated minor (<0.5°C) to practically meaningful (>0.5°C) measurement bias within the subgroups of attachment type, applied pressure, environmental conditions, and sensor type. The 95% LoA were often within 1.0°C for in vivo studies and 0.5°C for physical models. For the survey of use, 172 studies

A novel image-based BRDF measurement system and its application to human skin

NASA Astrophysics Data System (ADS)

Bintz, Jeffrey R.; Mendenhall, Michael J.; Marciniak, Michael A.; Butler, Samuel D.; Lloyd, James Tommy

2016-09-01

Human skin detection is an important first step in search and rescue (SAR) scenarios. Previous research performed human skin detection through an application specific camera system that ex- ploits the spectral properties of human skin at two visible and two near-infrared (NIR) wavelengths. The current theory assumes human skin is diffuse; however, it is observed that human skin exhibits specular and diffuse reflectance properties. This paper presents a novel image-based bidirectional reflectance distribution function (BRDF) measurement system, and applies it to the collection of human skin BRDF. The system uses a grid projecting laser and a novel signal processing chain to extract the surface normal from each grid location. Human skin BRDF measurements are shown for a variety of melanin content and hair coverage at the four spectral channels needed for human skin detection. The NIR results represent a novel contribution to the existing body of human skin BRDF measurements.

Elevated Skin Blood Flow Influences Near Infrared Spectroscopy Measurements During Supine Rest

NASA Technical Reports Server (NTRS)

Lee, Stuart M. C.; Clarke, Mark S. F.

2004-01-01

Near infrared spectroscopy is a non-invasive technique that allows determination of tissue oxygenation/blood flow based on spectrophotometric quantitation of oxy- and deoxyhemoglobin present within a tissue. This technique has gained acceptance as a means of detecting and quantifying changes in tissue blood flow due to physiological perturbation, such as that which is elicited in skeletal muscle during exercise. Since the NIRS technique requires light to penetrate the skin and subcutaneous fat in order to reach the muscle of interest, changes in skin blood flow may alter the NIRS signal in a fashion unrelated to blood flow in the muscle of interest. The aim of this study was to determine the contribution of skin blood flow to the NIRS signal obtained from resting vastus lateralis muscle of the thigh.

Thermistor holder for skin-temperature measurements

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Williams, B. A.

1974-01-01

Sensing head of thermistor probe is supported in center area of plastic ring which has tabs so that it can be anchored in place by rubber bands or adhesive tapes. Device attaches probes to human subjects practically, reliably, and without affecting characteristics of skin segment being measured.

Evaluating the consistency of location of the most severe acute skin reaction and highest skin dose measured by thermoluminescent dosimeter during radiotherapy for breast cancer.

PubMed

Sun, Li-Min; Huang, Chih-Jen; Chen, Hsiao-Yun; Chang, Gia-Hsin; Tsao, Min-Jen

2016-01-01

We conducted this prospective study to evaluate whether the location of the most severe acute skin reaction matches the highest skin dose measured by thermoluminescent dosimeter (TLD) during adjuvant radiotherapy (RT) for patients with breast cancer after breast conservative surgery. To determine whether TLD measurement can reflect the location of the most severe acute skin reaction, 80 consecutive patients were enrolled in this prospective study. We divided the irradiated field into breast, axillary, inframammary fold, and areola/nipple areas. In 1 treatment session when obvious skin reaction occurred, we placed the TLD chips onto the 4 areas and measured the skin dose. We determined whether the highest measured skin dose area is consistent with the location of the most severe skin reaction. The McNemar test revealed that the clinical skin reaction and TLD measurement are more consistent when the most severe skin reaction occurred at the axillary area, and the p = 0.0108. On the contrary, TLD measurement of skin dose is less likely consistent with clinical observation when the most severe skin reaction occurred at the inframammary fold, breast, and areola/nipple areas (all the p > 0.05). Considering the common site of severe skin reaction over the axillary area, TLD measurement may be an appropriate way to predict skin reaction during RT. Copyright © 2016 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

Automatic 3D segmentation of multiphoton images: a key step for the quantification of human skin.

PubMed

Decencière, Etienne; Tancrède-Bohin, Emmanuelle; Dokládal, Petr; Koudoro, Serge; Pena, Ana-Maria; Baldeweck, Thérèse

2013-05-01

Multiphoton microscopy has emerged in the past decade as a useful noninvasive imaging technique for in vivo human skin characterization. However, it has not been used until now in evaluation clinical trials, mainly because of the lack of specific image processing tools that would allow the investigator to extract pertinent quantitative three-dimensional (3D) information from the different skin components. We propose a 3D automatic segmentation method of multiphoton images which is a key step for epidermis and dermis quantification. This method, based on the morphological watershed and graph cuts algorithms, takes into account the real shape of the skin surface and of the dermal-epidermal junction, and allows separating in 3D the epidermis and the superficial dermis. The automatic segmentation method and the associated quantitative measurements have been developed and validated on a clinical database designed for aging characterization. The segmentation achieves its goals for epidermis-dermis separation and allows quantitative measurements inside the different skin compartments with sufficient relevance. This study shows that multiphoton microscopy associated with specific image processing tools provides access to new quantitative measurements on the various skin components. The proposed 3D automatic segmentation method will contribute to build a powerful tool for characterizing human skin condition. To our knowledge, this is the first 3D approach to the segmentation and quantification of these original images. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Quantitative comparison of inflammatory infiltrate and linear contraction in human skin treated with 90-microsecond pulsed and 900-microsecond dwell time carbon dioxide lasers.

PubMed

Bucalo, B D; Moy, R L

1998-12-01

Skin resurfacing with 90-microsecond pulse duration carbon dioxide (CO2) resurfacing lasers has been reported to have shorter duration of erythema compared with skin resurfacing with 900-microsecond dwell time lasers. The presence of inflammatory infiltrate following resurfacing may correlate with the persistence of this erythema. Furthermore, skin treated with the 90-microsecond pulse duration laser and the 900-microsecond dwell time lasers both result in equivalent improvement of rhytids in the treated skin. To quantitative the inflammatory cell infiltrate and linear contraction of skin treated with the 90-microsecond pulsed and 900-microsecond dwell time CO2 lasers at intervals of 2 and 4 weeks after treatment. Volunteers were recruited from patients who were planning to undergo full face laser resurfacing under general anesthesia. Informed consent was obtained from all volunteers. In the posterior auricular areas of all volunteers, four separate rectangular areas were marked using a skin marking pen and a template. Two rectangular areas behind the right ear were treated with 6 passes of the 90-microsecond laser and two rectangular areas behind the left ear were treated with the 900-microsecond dwell time laser. The resurfaced areas were wiped with a moist cotton swab and then patted dry with dry gauze between passes. Contraction measurements of the resurfaced areas were taken before and immediately after laser treatment and again at 2 and 4 weeks following treatment. Punch biopsies were also performed at 2 and 4 weeks after treatment in an area of skin different from where contraction measurements were taken. The number of inflammatory cells present in the skin at 2 and 4 weeks after laser resurfacing are greater for skin resurfaced with a 900-microsecond dwell time laser than a 90-microsecond pulse time laser. Linear contraction of skin immediately after treatment was 18% greater with the 900-microsecond dwell time laser than with the 90-microsecond pulsed

Image analysis of skin color heterogeneity focusing on skin chromophores and the age-related changes in facial skin.

PubMed

Kikuchi, Kumiko; Masuda, Yuji; Yamashita, Toyonobu; Kawai, Eriko; Hirao, Tetsuji

2015-05-01

Heterogeneity with respect to skin color tone is one of the key factors in visual perception of facial attractiveness and age. However, there have been few studies on quantitative analyses of the color heterogeneity of facial skin. The purpose of this study was to develop image evaluation methods for skin color heterogeneity focusing on skin chromophores and then characterize ethnic differences and age-related changes. A facial imaging system equipped with an illumination unit and a high-resolution digital camera was used to develop image evaluation methods for skin color heterogeneity. First, melanin and/or hemoglobin images were obtained using pigment-specific image-processing techniques, which involved conversion from Commission Internationale de l'Eclairage XYZ color values to melanin and/or hemoglobin indexes as measures of their contents. Second, a spatial frequency analysis with threshold settings was applied to the individual images. Cheek skin images of 194 healthy Asian and Caucasian female subjects were acquired using the imaging system. Applying this methodology, the skin color heterogeneity of Asian and Caucasian faces was characterized. The proposed pigment-specific image-processing techniques allowed visual discrimination of skin redness from skin pigmentation. In the heterogeneity analyses of cheek skin color, age-related changes in melanin were clearly detected in Asian and Caucasian skin. Furthermore, it was found that the heterogeneity indexes of hemoglobin were significantly higher in Caucasian skin than in Asian skin. We have developed evaluation methods for skin color heterogeneity by image analyses based on the major chromophores, melanin and hemoglobin, with special reference to their size. This methodology focusing on skin color heterogeneity should be useful for better understanding of aging and ethnic differences. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluating the consistency of location of the most severe acute skin reaction and highest skin dose measured by thermoluminescent dosimeter during radiotherapy for breast cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Li-Min, E-mail: limin.sun@yahoo.com; Huang, Chih-Jen; Department of Faculty of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

We conducted this prospective study to evaluate whether the location of the most severe acute skin reaction matches the highest skin dose measured by thermoluminescent dosimeter (TLD) during adjuvant radiotherapy (RT) for patients with breast cancer after breast conservative surgery. To determine whether TLD measurement can reflect the location of the most severe acute skin reaction, 80 consecutive patients were enrolled in this prospective study. We divided the irradiated field into breast, axillary, inframammary fold, and areola/nipple areas. In 1 treatment session when obvious skin reaction occurred, we placed the TLD chips onto the 4 areas and measured the skinmore » dose. We determined whether the highest measured skin dose area is consistent with the location of the most severe skin reaction. The McNemar test revealed that the clinical skin reaction and TLD measurement are more consistent when the most severe skin reaction occurred at the axillary area, and the p = 0.0108. On the contrary, TLD measurement of skin dose is less likely consistent with clinical observation when the most severe skin reaction occurred at the inframammary fold, breast, and areola/nipple areas (all the p > 0.05). Considering the common site of severe skin reaction over the axillary area, TLD measurement may be an appropriate way to predict skin reaction during RT.« less

The physiological and phenotypic determinants of human tanning measured as change in skin colour following a single dose of ultraviolet B radiation.

PubMed

Wong, Terence H; Jackson, Ian J; Rees, Jonathan L

2010-07-01

Experimental study of the in vivo kinetics of tanning in human skin has been limited by the difficulties in measuring changes in melanin pigmentation independent of the ultravioletinduced changes in erythema. The present study attempted to experimentally circumvent this issue. We have studied erythemal and tanning responses following a single exposure to a range of doses of ultraviolet B irradiation on the buttock and the lower back in 98 subjects. Erythema was assessed using reflectance techniques at 24 h and tanning measured as the L* spectrophotometric score at 7 days following noradrenaline iontophoresis. We show that dose (P < 0.0001), body site (P < 0.0001), skin colour (P < 0.0001), ancestry (P = 0.0074), phototype (P = 0.0019) and sex (P = 0.04) are all independent predictors of erythema. Quantitative estimates of the effects of these variables are reported, but the effects of ancestry and phototype do not appear solely explainable in terms of L* score. Dose (P < 0.0001), body site (P < 0.0001) and skin colour (P = 0.0365) or, as an alternative to skin colour, skin type (P = 0.0193) predict tanning, with those with lighter skin tanning slightly more to a defined UVB dose. If erythema is factored into the regression, then only dose and body site remain significant predictors of tanning: therefore neither phototype nor pigmentary factors, such as baseline skin colour, or eye or hair colour, predict change in skin colour to a unit erythemal response.

A new, objective, quantitative scale for measuring local skin responses following topical actinic keratosis therapy with ingenol mebutate.

PubMed

Rosen, Robert; Marmur, Ellen; Anderson, Lawrence; Welburn, Peter; Katsamas, Janelle

2014-12-01

Local skin responses (LSRs) are the most common adverse effects of topical actinic keratosis (AK) therapy. There is currently no method available that allows objective characterization of LSRs. Here, the authors describe a new scale developed to quantitatively and objectively assess the six most common LSRs resulting from topical AK therapy with ingenol mebutate. The LSR grading scale was developed using a 0-4 numerical rating, with clinical descriptors and representative photographic images for each rating. Good inter-observer grading concordance was demonstrated in peer review during development of the tool. Data on the use of the scale are described from four phase III double-blind studies of ingenol mebutate (n = 1,005). LSRs peaked on days 4 (face/scalp) or 8 (trunk/extremities), with mean maximum composite LSR scores of 9.1 and 6.8, respectively, and a rapid return toward baseline by day 15 in most cases. Mean composite LSR score at day 57 was generally lower than at baseline. The LSR grading scale is an objective tool allowing practicing dermatologists to characterize and compare LSRs to existing and, potentially, future AK therapies.

Objective measures for quality assessment of automatic skin enhancement algorithms

NASA Astrophysics Data System (ADS)

Ciuc, Mihai; Capata, Adrian; Florea, Corneliu

2010-01-01

Automatic portrait enhancement by attenuating skin flaws (pimples, blemishes, wrinkles, etc.) has received considerable attention from digital camera manufacturers thanks to its impact on the public. Subsequently, a number of algorithms have been developed to meet this need. One central aspect to developing such an algorithm is quality assessment: having a few numbers that precisely indicate the amount of beautification brought by an algorithm (as perceived by human observers) is of great help, as it works on circumvent time-costly human evaluation. In this paper, we propose a method to numerically evaluate the quality of a skin beautification algorithm. The most important aspects we take into account and quantize to numbers are the quality of the skin detector, the amount of smoothing performed by the method, the preservation of intrinsic skin texture, and the preservation of facial features. We combine these measures into two numbers that assess the quality of skin detection and beautification. The derived measures are highly correlated with human perception, therefore they constitute a helpful tool for tuning and comparing algorithms.

Optical skin friction measurement technique in hypersonic wind tunnel

NASA Astrophysics Data System (ADS)

Chen, Xing; Yao, Dapeng; Wen, Shuai; Pan, Junjie

2016-10-01

Shear-sensitive liquid-crystal coatings (SSLCCs) have an optical characteristic that they are sensitive to the applied shear stress. Based on this, a novel technique is developed to measure the applied shear stress of the model surface regarding both its magnitude and direction in hypersonic flow. The system of optical skin friction measurement are built in China Academy of Aerospace Aerodynamics (CAAA). A series of experiments of hypersonic vehicle is performed in wind tunnel of CAAA. Global skin friction distribution of the model which shows complicated flow structures is discussed, and a brief mechanism analysis and an evaluation on optical measurement technique have been made.

Tissue dielectric constant (TDC) as an index of localized arm skin water: differences between measuring probes and genders.

PubMed

Mayrovitz, H N; Weingrad, D N; Brlit, F; Lopez, L B; Desfor, R

2015-03-01

An easily measured, non-invasive, quantitative estimate of local skin tissue water is useful to assess local lymphedema and its change. One method uses skin tissue dielectric constant (TDC) values that at 300 MHz TDC depend on free and bound water within the measurement volume. In practice such measurements have been done with a research-type multi-probe, but recently a hand-held compact-probe has become available that may be more clinically convenient. Because most available published data is based on multiprobe measurements it is important to characterize possible differences between devices that unless known might lead to ambiguous quantitative comparisons between TDC values. Thus, our purpose was to evaluate potential differences in measured TDC values between multi-probe and compact-probe devices with respect to probe effective sampling depth, anatomical site, and gender and also to compare compact-probe TDC values measured on women with and without breast cancer (BC). TDC was measured bilaterally on forearms and biceps of 32 male and 32 female volunteers and on 12 female patients awaiting surgery for breast cancer. Results show that 1) TDC values at 2.5 mm depth were significantly less than at 1.5 mm; 2) Female TDC values were significantly less than male values; 3) TDC values were not different between females with and without BC; and 4) dominant/non-dominant arm TDC ratios were not significantly different for any probe among genders or arm anatomical site. These findings indicate that probe type differences in absolute TDC values are present and should be taken into account when TDC values are compared. However, comparisons based on inter-arm TDC ratios are not statistically different among probes with respect to gender or anatomical location.

A critical analysis of single-frequency LCR databridge impedance measurements of human skin.

PubMed

White, Erick A; Orazem, Mark E; Bunge, Annette L

2011-06-01

Testing whether the barrier of skin samples has sufficient integrity for meaningful measurements of in-vitro chemical permeability is usually required when data are generated for regulatory purposes. Recently, skin integrity has been assessed using LCR databridge measurements, which are reported as resistances determined in either series (SER) or parallel (PAR) modes at a single frequency, typically 100 or 1000Hz. Measurements made at different combinations of mode and frequency are known to differ, although the skin literature reveals confusion over the meaning of these differences and the impact on the interpretation of integrity test results. Here, the theoretical meanings of resistance and capacitance measurements in PAR and SER mode are described and confirmed experimentally. SER-mode resistances are equal to the real part of the complex impedance; whereas, PAR-mode resistances are the inverse of the real part of the admittance. Capacitance measurements reported in SER and PAR modes are similar manipulations of the imaginary parts of the complex impedance and admittance. A large body of data from human cadaver skin is used to show that the PAR-mode resistance and SER-mode capacitance measured at 100Hz are sensitive to skin resistivity, which is the electrical measurement most closely related to skin integrity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of an improved fiberoptics luminescence skin monitor with background correction.

PubMed

Vo-Dinh, T

1987-06-01

In this work, an improved version of a fiberoptics luminescence monitor, the prototype luminoscope II, is evaluated for in situ quantitative measurements. The instrument was developed to detect traces of luminescing organic contaminants on skin. An electronic background-nulling system was designed and incorporated into the instrument to compensate for various skin background emissions. A dose-response curve for a coal liquid spotted on mouse skin was established. The results illustrated the usefulness of the instrument for in vivo detection of organic materials on laboratory mouse skin.

Predicting human skin absorption of chemicals: development of a novel quantitative structure activity relationship.

PubMed

Luo, Wen; Medrek, Sarah; Misra, Jatin; Nohynek, Gerhard J

2007-02-01

The objective of this study was to construct and validate a quantitative structure-activity relationship model for skin absorption. Such models are valuable tools for screening and prioritization in safety and efficacy evaluation, and risk assessment of drugs and chemicals. A database of 340 chemicals with percutaneous absorption was assembled. Two models were derived from the training set consisting 306 chemicals (90/10 random split). In addition to the experimental K(ow) values, over 300 2D and 3D atomic and molecular descriptors were analyzed using MDL's QsarIS computer program. Subsequently, the models were validated using both internal (leave-one-out) and external validation (test set) procedures. Using the stepwise regression analysis, three molecular descriptors were determined to have significant statistical correlation with K(p) (R2 = 0.8225): logK(ow), X0 (quantification of both molecular size and the degree of skeletal branching), and SsssCH (count of aromatic carbon groups). In conclusion, two models to estimate skin absorption were developed. When compared to other skin absorption QSAR models in the literature, our model incorporated more chemicals and explored a large number of descriptors. Additionally, our models are reasonably predictive and have met both internal and external statistical validations.

High-definition optical coherence tomography intrinsic skin ageing assessment in women: a pilot study.

PubMed

Boone, M A L M; Suppa, M; Marneffe, A; Miyamoto, M; Jemec, G B E; Del Marmol, V

2015-10-01

Several non-invasive two-dimensional techniques with different lateral resolution and measurable depth range have proved to be useful in assessing and quantifying morphological changes in skin ageing. Among these, only in vivo microscopy techniques permit histometric measurements in vivo. Qualitative and quantitative assessment of chronological (intrinsic) age-related (IAR) morphological changes of epidermis, dermo-epidermal junction (DEJ), papillary dermis (PD), papillary-reticular dermis junction and reticular dermis (RD) have been performed by high-definition optical coherence tomography in real time 3-D. HD-OCT images were taken at the internal site of the right upper arm. Qualitative HD-OCT IAR descriptors were reported at skin surface, at epidermal layer, DEJ, PD and upper RD. Quantitative evaluation of age-related compaction and backscattered intensity or brightness of different skin layers was performed by using the plugin plot z-axis profile of ImageJ(®) software permitting intensity assessment of HD-OCT (DICOM) images (3-D images). Analysis was in blind from all clinical information. Sixty, fair-skinned (Fitzpatrick types I-III) healthy females were analysed retrospectively in this study. The subjects belonged to three age groups: twenty in group I aged 20-39, twenty in group II aged 40-59 and twenty in group III aged 60-79. Only intrinsic ageing in women has been studied. Significant age-related qualitative and quantitative differences could be noticed. IAR changes in dermal matrix fibers morphology/organisation and in microvasculature were observed. The brightness and compaction of the different skin layers increased significantly with intrinsic skin ageing. The depth of visibility of fibers in RD increased significantly in the older age group. In conclusion, HD-OCT allows 3-D in vivo and real time qualitative and quantitative assessment of chronological (intrinsic) age-related morphological skin changes at high resolution from skin surface to a depth

Reliability Concerns in Measuring Respondent Skin Tone by Interviewer Observation

PubMed Central

Hannon, Lance; DeFina, Robert

2016-01-01

The current study assesses the intercoder reliability of one of the most important skin tone measurement instruments—the Massey–Martin scale. This scale is used in several high-profile social surveys, but has not yet been psychometrically evaluated. The current evaluation is only possible because, for the first time, the General Social Survey’s 2010–2014 panel used the instrument to guide interviewers’ skin tone observation of the same respondents in two different years (2012 and 2014). Despite the widespread use of the Massey–Martin scale to investigate potential effects of skin tone on social attitudes and outcomes, the data suggest that the measure has low intercoder reliability. Implications for researchers and survey practitioners are discussed. PMID:27274576

Jet fuel toxicity: skin damage measured by 900-MHz MRI skin microscopy and visualization by 3D MR image processing.

PubMed

Sharma, Rakesh; Locke, Bruce R

2010-09-01

The toxicity of jet fuels was measured using noninvasive magnetic resonance microimaging (MRM) at 900-MHz magnetic field. The hypothesis was that MRM can visualize and measure the epidermis exfoliation and hair follicle size of rat skin tissue due to toxic skin irritation after skin exposure to jet fuels. High-resolution 900-MHz MRM was used to measure the change in size of hair follicle, epidermis thickening and dermis in the skin after jet fuel exposure. A number of imaging techniques utilized included magnetization transfer contrast (MTC), spin-lattice relaxation constant (T1-weighting), combination of T2-weighting with magnetic field inhomogeneity (T2*-weighting), magnetization transfer weighting, diffusion tensor weighting and chemical shift weighting. These techniques were used to obtain 2D slices and 3D multislice-multiecho images with high-contrast resolution and high magnetic resonance signal with better skin details. The segmented color-coded feature spaces after image processing of the epidermis and hair follicle structures were used to compare the toxic exposure to tetradecane, dodecane, hexadecane and JP-8 jet fuels. Jet fuel exposure caused skin damage (erythema) at high temperature in addition to chemical intoxication. Erythema scores of the skin were distinct for jet fuels. The multicontrast enhancement at optimized TE and TR parameters generated high MRM signal of different skin structures. The multiple contrast approach made visible details of skin structures by combining specific information achieved from each of the microimaging techniques. At short echo time, MRM images and digitized histological sections confirmed exfoliated epidermis, dermis thickening and hair follicle atrophy after exposure to jet fuels. MRM data showed correlation with the histopathology data for epidermis thickness (R(2)=0.9052, P<.0002) and hair root area (R(2)=0.88, P<.0002). The toxicity of jet fuels on skin structures was in the order of tetradecane

Friction coefficient of skin in real-time.

PubMed

Sivamani, Raja K; Goodman, Jack; Gitis, Norm V; Maibach, Howard I

2003-08-01

Friction studies are useful in quantitatively investigating the skin surface. Previous studies utilized different apparatuses and materials for these investigations but there was no real-time test parameter control or monitoring. Our studies incorporated the commercially available UMT Series Micro-Tribometer, a tribology instrument that permits real-time monitoring and calculation of the important parameters in friction studies, increasing the accuracy over previous tribology and friction measurement devices used on skin. Our friction tests were performed on four healthy volunteers and on abdominal skin samples. A stainless steel ball was pressed on to the skin with at a pre-set load and then moved across the skin at a constant velocity of 5 mm/min. The UMT continuously monitored the friction force of the skin and the normal force of the ball to calculate the friction coefficient in real-time. Tests investigated the applicability of Amonton's law, the impact of increased and decreased hydration, and the effect of the application of moisturizers. The friction coefficient depends on the normal load applied, and Amonton's law does not provide an accurate description for the skin surface. Application of water to the skin increased the friction coefficient and application of isopropyl alcohol decreased it. Fast acting moisturizers immediately increased the friction coefficient, but did not have the prolonged effect of the slow, long lasting moisturizers. The UMT is capable of making real-time measurements on the skin and can be used as an effective tool to study friction properties. Results from the UMT measurements agree closely with theory regarding the skin surface.

Raman spectroscopy of human skin: looking for a quantitative algorithm to reliably estimate human age

NASA Astrophysics Data System (ADS)

Pezzotti, Giuseppe; Boffelli, Marco; Miyamori, Daisuke; Uemura, Takeshi; Marunaka, Yoshinori; Zhu, Wenliang; Ikegaya, Hiroshi

2015-06-01

The possibility of examining soft tissues by Raman spectroscopy is challenged in an attempt to probe human age for the changes in biochemical composition of skin that accompany aging. We present a proof-of-concept report for explicating the biophysical links between vibrational characteristics and the specific compositional and chemical changes associated with aging. The actual existence of such links is then phenomenologically proved. In an attempt to foster the basics for a quantitative use of Raman spectroscopy in assessing aging from human skin samples, a precise spectral deconvolution is performed as a function of donors' ages on five cadaveric samples, which emphasizes the physical significance and the morphological modifications of the Raman bands. The outputs suggest the presence of spectral markers for age identification from skin samples. Some of them appeared as authentic "biological clocks" for the apparent exactness with which they are related to age. Our spectroscopic approach yields clear compositional information of protein folding and crystallization of lipid structures, which can lead to a precise identification of age from infants to adults. Once statistically validated, these parameters might be used to link vibrational aspects at the molecular scale for practical forensic purposes.

Towards quantitative assessment of calciphylaxis

NASA Astrophysics Data System (ADS)

Deserno, Thomas M.; Sárándi, István.; Jose, Abin; Haak, Daniel; Jonas, Stephan; Specht, Paula; Brandenburg, Vincent

2014-03-01

Calciphylaxis is a rare disease that has devastating conditions associated with high morbidity and mortality. Calciphylaxis is characterized by systemic medial calcification of the arteries yielding necrotic skin ulcerations. In this paper, we aim at supporting the installation of multi-center registries for calciphylaxis, which includes a photographic documentation of skin necrosis. However, photographs acquired in different centers under different conditions using different equipment and photographers cannot be compared quantitatively. For normalization, we use a simple color pad that is placed into the field of view, segmented from the image, and its color fields are analyzed. In total, 24 colors are printed on that scale. A least-squares approach is used to determine the affine color transform. Furthermore, the card allows scale normalization. We provide a case study for qualitative assessment. In addition, the method is evaluated quantitatively using 10 images of two sets of different captures of the same necrosis. The variability of quantitative measurements based on free hand photography is assessed regarding geometric and color distortions before and after our simple calibration procedure. Using automated image processing, the standard deviation of measurements is significantly reduced. The coefficients of variations yield 5-20% and 2-10% for geometry and color, respectively. Hence, quantitative assessment of calciphylaxis becomes practicable and will impact a better understanding of this rare but fatal disease.

Measuring skin aging using optical coherence tomography in vivo: a validation study

NASA Astrophysics Data System (ADS)

Trojahn, Carina; Dobos, Gabor; Richter, Claudia; Blume-Peytavi, Ulrike; Kottner, Jan

2015-04-01

Dermal and epidermal structures in human skin change during intrinsic and extrinsic aging. Epidermal thickness is one of the most often reported parameters for the assessment of skin aging in cross-sectional images captured by optical coherence tomography (OCT). We aimed to identify further parameters for the noninvasive measurement of skin aging of sun-exposed and sun-protected areas utilizing OCT. Based on a literature review, seven parameters were inductively developed. Three independent raters assessed these parameters using four-point scales on images of female subjects of two age groups. All items could be detected and quantified in our sample. Interrater agreement ranged between 25.0% and 83.3%. The item scores "stratum corneum reflectivity," "upper dermal reflectivity," and "dermoepidermal contrast" showed significant differences between age groups on the volar and dorsal forearm indicating that they were best able to measure changes during skin aging. "Surface unevenness" was associated with the skin roughness parameters, Rz and Rmax, on the inner upper arm and volar forearm supporting the criterion validity of this parameter on sun-protected skin areas. Based on the interrater agreement and the ability to differentiate between age groups, these four parameters are being considered as the best candidates for measuring skin aging in OCT images.

Measuring skin aging using optical coherence tomography in vivo: a validation study.

PubMed

Trojahn, Carina; Dobos, Gabor; Richter, Claudia; Blume-Peytavi, Ulrike; Kottner, Jan

2015-04-01

Dermal and epidermal structures in human skin change during intrinsic and extrinsic aging. Epidermal thickness is one of the most often reported parameters for the assessment of skin aging in cross-sectional images captured by optical coherence tomography (OCT). We aimed to identify further parameters for the noninvasive measurement of skin aging of sun-exposed and sun-protected areas utilizing OCT. Based on a literature review, seven parameters were inductively developed. Three independent raters assessed these parameters using four-point scales on images of female subjects of two age groups. All items could be detected and quantified in our sample. Interrater agreement ranged between 25.0% and 83.3%. The item scores “stratum corneum reflectivity,” “upper dermal reflectivity,” and “dermoepidermal contrast” showed significant differences between age groups on the volar and dorsal forearm indicating that they were best able to measure changes during skin aging. “Surface unevenness” was associated with the skin roughness parameters, Rz and Rmax, on the inner upper arm and volar forearm supporting the criterion validity of this parameter on sun-protected skin areas. Based on the interrater agreement and the ability to differentiate between age groups, these four parameters are being considered as the best candidates for measuring skin aging in OCT images.

Quantitative measurement of hypertrophic scar: intrarater reliability, sensitivity, and specificity.

PubMed

Nedelec, Bernadette; Correa, José A; Rachelska, Grazyna; Armour, Alexis; LaSalle, Léo

2008-01-01

The comparison of scar evaluation over time requires measurement tools with acceptable intrarater reliability and the ability to discriminate skin characteristics of interest. The objective of this study was to evaluate the intrarater reliability and sensitivity and specificity of the Cutometer, the Mexameter, and the DermaScan C relative to the modified Vancouver Scar Scale (mVSS) in patient-matched normal skin, normal scar (donor sites), and hypertrophic scar (HSc). A single investigator evaluated four tissue types (severe HSc, less severe HSc, donor site, and normal skin) in 30 burn survivors with all four measurement tools. The intraclass correlation coefficient (ICC) for the Cutometer was acceptable (> or =0.75) for the maximum deformation measure for the donor site and normal skin (>0.78) but was below the acceptable range for the HSc sites and all other parameters. The ICC for the Mexameter erythema (>0.75) and melanin index (>0.89) and the DermaScan C total thickness measurement (>0.82) were acceptable for all sites. The ICC for the total of the height, pliability, and vascularity subscales of the mVSS was acceptable (0.81) for normal scar but below the acceptable range for the scar sites. The DermaScan C was clearly able to discriminate HSc from normal scar and normal skin based on the total thickness measure. The Cutometer was less discriminating but was still able to discriminate HSc from normal scar and normal skin. The Mexameter erythema index was not a good discriminator of HSc and normal scar. Receiver operating characteristic curves were generated to establish the best cutoff point for the DermaScan C total thickness and the Cutometer maximum deformation, which were 2.034 and 0.387 mm, respectively. This study showed that although the Cutometer, the DermaScan C, and the Mexameter have measurement properties that make them attractive substitutes for the mVSS, caution must be used when interpreting results since the Cutometer has a ceiling effect when

Skin dose measurements using MOSFET and TLD for head and neck patients treated with tomotherapy.

PubMed

Kinhikar, Rajesh A; Murthy, Vedang; Goel, Vineeta; Tambe, Chandrashekar M; Dhote, Dipak S; Deshpande, Deepak D

2009-09-01

The purpose of this work was to estimate skin dose for the patients treated with tomotherapy using metal oxide semiconductor field-effect transistors (MOSFETs) and thermoluminescent dosimeters (TLDs). In vivo measurements were performed for two head and neck patients treated with tomotherapy and compared to TLD measurements. The measurements were subsequently carried out for five days to estimate the inter-fraction deviations in MOSFET measurements. The variation between skin dose measured with MOSFET and TLD for first patient was 2.2%. Similarly, the variation of 2.3% was observed between skin dose measured with MOSFET and TLD for second patient. The tomotherapy treatment planning system overestimated the skin dose as much as by 10-12% when compared to both MOSFET and TLD. However, the MOSFET measured patient skin doses also had good reproducibility, with inter-fraction deviations ranging from 1% to 1.4%. MOSFETs may be used as a viable dosimeter for measuring skin dose in areas where the treatment planning system may not be accurate.

Automated skin segmentation in ultrasonic evaluation of skin toxicity in breast cancer radiotherapy.

PubMed

Gao, Yi; Tannenbaum, Allen; Chen, Hao; Torres, Mylin; Yoshida, Emi; Yang, Xiaofeng; Wang, Yuefeng; Curran, Walter; Liu, Tian

2013-11-01

Skin toxicity is the most common side effect of breast cancer radiotherapy and impairs the quality of life of many breast cancer survivors. We, along with other researchers, have recently found quantitative ultrasound to be effective as a skin toxicity assessment tool. Although more reliable than standard clinical evaluations (visual observation and palpation), the current procedure for ultrasound-based skin toxicity measurements requires manual delineation of the skin layers (i.e., epidermis-dermis and dermis-hypodermis interfaces) on each ultrasound B-mode image. Manual skin segmentation is time consuming and subjective. Moreover, radiation-induced skin injury may decrease image contrast between the dermis and hypodermis, which increases the difficulty of delineation. Therefore, we have developed an automatic skin segmentation tool (ASST) based on the active contour model with two significant modifications: (i) The proposed algorithm introduces a novel dual-curve scheme for the double skin layer extraction, as opposed to the original single active contour method. (ii) The proposed algorithm is based on a geometric contour framework as opposed to the previous parametric algorithm. This ASST algorithm was tested on a breast cancer image database of 730 ultrasound breast images (73 ultrasound studies of 23 patients). We compared skin segmentation results obtained with the ASST with manual contours performed by two physicians. The average percentage differences in skin thickness between the ASST measurement and that of each physician were less than 5% (4.8 ± 17.8% and -3.8 ± 21.1%, respectively). In summary, we have developed an automatic skin segmentation method that ensures objective assessment of radiation-induced changes in skin thickness. Our ultrasound technology offers a unique opportunity to quantify tissue injury in a more meaningful and reproducible manner than the subjective assessments currently employed in the clinic. Copyright © 2013 World

Skin Parameter Map Retrieval from a Dedicated Multispectral Imaging System Applied to Dermatology/Cosmetology

PubMed Central

2013-01-01

In vivo quantitative assessment of skin lesions is an important step in the evaluation of skin condition. An objective measurement device can help as a valuable tool for skin analysis. We propose an explorative new multispectral camera specifically developed for dermatology/cosmetology applications. The multispectral imaging system provides images of skin reflectance at different wavebands covering visible and near-infrared domain. It is coupled with a neural network-based algorithm for the reconstruction of reflectance cube of cutaneous data. This cube contains only skin optical reflectance spectrum in each pixel of the bidimensional spatial information. The reflectance cube is analyzed by an algorithm based on a Kubelka-Munk model combined with evolutionary algorithm. The technique allows quantitative measure of cutaneous tissue and retrieves five skin parameter maps: melanin concentration, epidermis/dermis thickness, haemoglobin concentration, and the oxygenated hemoglobin. The results retrieved on healthy participants by the algorithm are in good accordance with the data from the literature. The usefulness of the developed technique was proved during two experiments: a clinical study based on vitiligo and melasma skin lesions and a skin oxygenation experiment (induced ischemia) with healthy participant where normal tissues are recorded at normal state and when temporary ischemia is induced. PMID:24159326

Skin-Friction Measurements in a 3-D, Supersonic Shock-Wave/Boundary-Layer Interaction

NASA Technical Reports Server (NTRS)

Wideman, J. K.; Brown, J. L.; Miles, J. B.; Ozcan, O.

1994-01-01

The experimental documentation of a three-dimensional shock-wave/boundary-layer interaction in a nominal Mach 3 cylinder, aligned with the free-stream flow, and 20 deg. half-angle conical flare offset 1.27 cm from the cylinder centerline. Surface oil flow, laser light sheet illumination, and schlieren were used to document the flow topology. The data includes surface-pressure and skin-friction measurements. A laser interferometric skin friction data. Included in the skin-friction data are measurements within separated regions and three-dimensional measurements in highly-swept regions. The skin-friction data will be particularly valuable in turbulence modeling and computational fluid dynamics validation.

Skin friction measurements in high temperature high speed flows

NASA Technical Reports Server (NTRS)

Schetz, J. A.; Diller, Thomas E.; Wicks, A. L.

1992-01-01

An experimental investigation was conducted to measure skin friction along the chamber walls of supersonic combustors. A direct force measurement device was used to simultaneously measure an axial and transverse component of the small tangential shear force passing over a non-intrusive floating element. The floating head is mounted to a stiff cantilever beam arrangement with deflection due to the flow on the order of 0.00254 mm (0.0001 in.). This allowed the instrument to be a non-nulling type. A second gauge was designed with active cooling of the floating sensor head to eliminate non-uniform temperature effects between the sensor head and the surrounding wall. Samples of measurements made in combustor test facilities at NASA Langley Research Center and at the General Applied Science Laboratory (GASL) are presented. Skin friction coefficients between 0.001 - 0.005 were measured dependent on the facility and measurement location. Analysis of the measurement uncertainties indicate an accuracy to within +/- 10-15 percent of the streamwise component.

Comparison of intradermal dilutional testing, skin prick testing, and modified quantitative testing for common allergens.

PubMed

Peltier, Jacques; Ryan, Matthew W

2007-08-01

To compare and correlate wheal size using the Multi-Test II applicator with the endpoint obtained by intradermal dilutional testing (IDT) for 5 common allergens. To examine the safety of modified quantitative testing (MQT) for determining immunotherapy starting doses. Prospective comparative clinical study. A total of 134 subjects were simultaneously skin tested for immediate hypersensitivity using the Multi-Test II device and IDT. There was a 77% concordance between results from IDT and results from MQT. When there was a difference, MQT predicted a safer endpoint for starting immunotherapy in all but 2 cases. Wheal size by SPT is predictive of endpoint by IDT. MQT is nearly as effective as formal IDT in determining endpoint. Modified quantitative testing appears to be a safe alternative to IDT for determining starting doses for immunotherapy.

Age and Hydration dependence of jowl and forearm skin firmness in young and mature women.

PubMed

Mayrovitz, Harvey N; Wong, Jennifer; Fasen, Madeline

2017-12-27

Quantitative assessment of possible linkages between skin's firmness and water content is useful for cosmetic and clinical purposes and to better understand features of advancing age. Our goals were to characterize age-related differential features in skin firmness in women and determine the relationship between skin firmness and indices of skin water. Skin firmness was quantified using handheld devices that measure the force to indent skin 0.3 and 1.3 mm (F0.3 and F1.3). Skin hydration was quantified using handheld devices that measured tissue dielectric constant (TDC) at 300 MHz to skin depths of 0.5 and 2.0-2.5 mm. All parameters were measured bilaterally in the jowl area and volar forearm of 60 women grouped by age <45 years (YOUNG) and ≥45 years old (MATURE). All measured parameters were bilaterally symmetrical at jowl and forearm. Forearm and jowl indentation forces were greater in YOUNG with statistically significant declines with advancing age with regression relations most evident at shallower indentation depths (P < .001). Quantitative relations for arm and jowl were F 0.3 = 0.256 × AGE + 32.7 mN and F 0.3 = -0.07 × AGE + 17.7 mN. Firmness was related to TDC values only when indentation force and TDC were assessed on the arm at the shallowest skin depths, as weakly related to firmness and was observed to change with age only when measured to a depth of 0.5 mm represented by TDC5 = 0.096 × AGE + 32.7. Experimental finding show clear differences in skin firmness between age-groups with skin hydration playing a minor role. Possible explanations and suggestions for further studies are provided. © 2017 Wiley Periodicals, Inc.

A new quantitative evaluation method for age-related changes of individual pigmented spots in facial skin.

PubMed

Kikuchi, K; Masuda, Y; Yamashita, T; Sato, K; Katagiri, C; Hirao, T; Mizokami, Y; Yaguchi, H

2016-08-01

Facial skin pigmentation is one of the most prominent visible features of skin aging and often affects perception of health and beauty. To date, facial pigmentation has been evaluated using various image analysis methods developed for the cosmetic and esthetic fields. However, existing methods cannot provide precise information on pigmented spots, such as variations in size, color shade, and distribution pattern. The purpose of this study is the development of image evaluation methods to analyze individual pigmented spots and acquire detailed information on their age-related changes. To characterize the individual pigmented spots within a cheek image, we established a simple object-counting algorithm. First, we captured cheek images using an original imaging system equipped with an illumination unit and a high-resolution digital camera. The acquired images were converted into melanin concentration images using compensation formulae. Next, the melanin images were converted into binary images. The binary images were then subjected to noise reduction. Finally, we calculated parameters such as the melanin concentration, quantity, and size of individual pigmented spots using a connected-components labeling algorithm, which assigns a unique label to each separate group of connected pixels. The cheek image analysis was evaluated on 643 female Japanese subjects. We confirmed that the proposed method was sufficiently sensitive to measure the melanin concentration, and the numbers and sizes of individual pigmented spots through manual evaluation of the cheek images. The image analysis results for the 643 Japanese women indicated clear relationships between age and the changes in the pigmented spots. We developed a new quantitative evaluation method for individual pigmented spots in facial skin. This method facilitates the analysis of the characteristics of various pigmented facial spots and is directly applicable to the fields of dermatology, pharmacology, and esthetic

SU-E-I-53: Variation in Measurements of Breast Skin Thickness Obtained Using Different Imaging Modalities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, U; Kumaraswamy, N; Markey, M

Purpose: To investigate variation in measurements of breast skin thickness obtained using different imaging modalities, including mammography, computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI). Methods: Breast skin thicknesses as measured by mammography, CT, ultrasound, and MRI were compared. Mammographic measurements of skin thickness were obtained from published studies that utilized standard positioning (upright) and compression. CT measurements of skin thickness were obtained from a published study of a prototype breast CT scanner in which the women were in the prone position and the breast was uncompressed. Dermatological ultrasound exams of the breast skin were conducted at our institution,more » with the subjects in the upright position and the breast uncompressed. Breast skin thickness was calculated from breast MRI exams at our institution, with the patient in the prone position and the breast uncompressed. Results: T tests for independent samples demonstrated significant differences in the mean breast skin thickness as measured by different imaging modalities. Repeated measures ANOVA revealed significant differences in breast skin thickness across different quadrants of the breast for some modalities. Conclusion: The measurement of breast skin thickness is significantly different across different imaging modalities. Differences in the amount of compression and differences in patient positioning are possible reasons why measurements of breast skin thickness vary by modality.« less

Quantitative determination of a-Arbutin, ß-Arbutin, Kojic acid, nicotinamide, hydroquinone, resorcinol, 4-methoxyphenol, 4-ethoxyphenol and ascorbic acid from skin whitening Products by HPLC-UV

USDA-ARS?s Scientific Manuscript database

Development of an analytical method for the simultaneous determination of multifarious skin whitening agents will provide an efficient tool to analyze skin whitening cosmetics. An HPLC-UV method was developed for quantitative analysis of six commonly used whitening agents, a-arbutin, ß-arbutin, koji...

Quantitative skin prick and bronchial provocation tests with platinum salt.

PubMed Central

Merget, R; Schultze-Werninghaus, G; Bode, F; Bergmann, E M; Zachgo, W; Meier-Sydow, J

1991-01-01

Occupational asthma due to platinum salts is a frequent disease in platinum refineries. The diagnosis is based upon a history of work related symptoms and a positive skin prick test with platinum salts. Bronchial provocation tests have not been performed in epidemiological studies because the skin test is believed to be highly specific and sensitive. As no reliable data about this issue currently exist, this study assesses the use of skin prick and bronchial provocation tests with methacholine and platinum salt in platinum refinery workers. Twenty seven of 35 workers, who were referred to our clinic with work related symptoms and nine control subjects with bronchial hyperreactivity underwent a skin prick test and bronchial provocation with methacholine and platinum salt. For skin prick and bronchial provocation tests with platinum salt a 10(-2)-10(-8) mol/l hexachloroplatinic acid solution, in 10-fold dilutions was used. Four of the 27 subjects and all controls showed neither a bronchial reaction nor a skin reaction. Twenty three subjects were considered allergic to platinum salt; 22 of these showed a fall of 50% or more in specific airway conductance after inhalation of the platinum salt solution. Four workers experienced a positive bronchial reaction despite a negative skin prick test. No correlation of responsiveness to methacholine with responsiveness to platinum salt was found, but the skin prick test correlated with the bronchial reaction to platinum salt (rs = 0.50, p less than 0.023, n = 22). One dual reaction was seen in bronchial provocation tests. Side effects of both skin tests and bronchial provocation tests with platinum salt were rare and were not encountered in workers without a skin reaction to platinum salt. It is concluded that bronchial provocation tests with platinum salts should be performed on workers with work related symptoms but negative skin tests with platinum salts. PMID:1772797

Method and apparatus to measure the depth of skin burns

DOEpatents

Dickey, Fred M.; Holswade, Scott C.

2002-01-01

A new device for measuring the depth of surface tissue burns based on the rate at which the skin temperature responds to a sudden differential temperature stimulus. This technique can be performed without physical contact with the burned tissue. In one implementation, time-dependent surface temperature data is taken from subsequent frames of a video signal from an infrared-sensitive video camera. When a thermal transient is created, e.g., by turning off a heat lamp directed at the skin surface, the following time-dependent surface temperature data can be used to determine the skin burn depth. Imaging and non-imaging versions of this device can be implemented, thereby enabling laboratory-quality skin burn depth imagers for hospitals as well as hand-held skin burn depth sensors the size of a small pocket flashlight for field use and triage.

Boundary-layer transition and global skin friction measurement with an oil-fringe imaging technique

NASA Technical Reports Server (NTRS)

Monson, Daryl J.; Mateer, George G.; Menter, Florian R.

1993-01-01

A new oil-fringe imaging system skin friction (FISF) technique to measure skin friction on wind tunnel models is presented. In the method used to demonstrate the technique, lines of oil are applied on surfaces that connect the intended sets of measurement points, and then a wind tunnel is run so that the oil thins and forms interference fringes that are spaced in proportion to local skin friction. After a run the fringe spacings are imaged with a CCD-array digital camera and measured on a computer. Skin friction and transition measurements on a two-dimensional wing are presented and compared with computational predictions.

Comparison of protocols for measuring cosmetic ingredient distribution in human and pig skin.

PubMed

Gerstel, D; Jacques-Jamin, C; Schepky, A; Cubberley, R; Eilstein, J; Grégoire, S; Hewitt, N; Klaric, M; Rothe, H; Duplan, H

2016-08-01

The Cosmetics Europe Skin Bioavailability and Metabolism Task Force aims to improve the measurement and prediction of the bioavailability of topically-exposed compounds for risk assessment. Key parameters of the experimental design of the skin penetration studies were compared. Penetration studies with frozen human and pig skin were conducted in two laboratories, according to the SCCS and OECD 428 guidelines. The disposition in skin was measured 24h after finite topical doses of caffeine, resorcinol and 7-ethoxycoumarin. The bioavailability distribution in skin layers of cold and radiolabelled chemicals were comparable. Furthermore, the distribution of each chemical was comparable in human and pig skin. The protocol was reproducible across the two laboratories. There were small differences in the amount of chemical detected in the skin layers, which were attributed to differences in washing procedures and anatomical sites of the skin used. In conclusion, these studies support the use of pig skin as an alternative source of skin should the availability of human skin become a limiting factor. If radiolabelled chemicals are not available, cold chemicals can be used, provided that the influence of chemical stability, reactivity or metabolism on the experimental design and the relevance of the data obtained is considered. Copyright © 2016. Published by Elsevier Ltd.

A laser interferometer for measuring skin friction in three-dimensional flows

NASA Technical Reports Server (NTRS)

Monson, D. J.

1983-01-01

A new, nonintrusive method is described for measuring skin friction in three-dimensional flows with unknown direction. The method uses a laser interferometer to measure the changing slope of a thin oil film applied to a surface experiencing shear stress. The details of the method are described, and skin friction measurements taken in a swirling three-dimensional boundary-layer flow are presented. Comparisons between analytical results and experimental values from the laser interferometer method and from a bidirectional surface-fence gauge are made.

The Impact of Quantitative Data Provided by a Multi-spectral Digital Skin Lesion Analysis Device on Dermatologists'Decisions to Biopsy Pigmented Lesions.

PubMed

Farberg, Aaron S; Winkelmann, Richard R; Tucker, Natalie; White, Richard; Rigel, Darrell S

2017-09-01

BACKGROUND: Early diagnosis of melanoma is critical to survival. New technologies, such as a multi-spectral digital skin lesion analysis (MSDSLA) device [MelaFind, STRATA Skin Sciences, Horsham, Pennsylvania] may be useful to enhance clinician evaluation of concerning pigmented skin lesions. Previous studies evaluated the effect of only the binary output. OBJECTIVE: The objective of this study was to determine how decisions dermatologists make regarding pigmented lesion biopsies are impacted by providing both the underlying classifier score (CS) and associated probability risk provided by multi-spectral digital skin lesion analysis. This outcome was also compared against the improvement reported with the provision of only the binary output. METHODS: Dermatologists attending an educational conference evaluated 50 pigmented lesions (25 melanomas and 25 benign lesions). Participants were asked if they would biopsy the lesion based on clinical images, and were asked this question again after being shown multi-spectral digital skin lesion analysis data that included the probability graphs and classifier score. RESULTS: Data were analyzed from a total of 160 United States board-certified dermatologists. Biopsy sensitivity for melanoma improved from 76 percent following clinical evaluation to 92 percent after quantitative multi-spectral digital skin lesion analysis information was provided ( p <0.0001). Specificity improved from 52 percent to 79 percent ( p <0.0001). The positive predictive value increased from 61 percent to 81 percent ( p <0.01) when the quantitative data were provided. Negative predictive value also increased (68% vs. 91%, p<0.01), and overall biopsy accuracy was greater with multi-spectral digital skin lesion analysis (64% vs. 86%, p <0.001). Interrater reliability improved (intraclass correlation 0.466 before, 0.559 after). CONCLUSION: Incorporating the classifier score and probability data into physician evaluation of pigmented lesions led to both

Imaging-guided two-photon excitation-emission-matrix measurements of human skin tissues

NASA Astrophysics Data System (ADS)

Yu, Yingqiu; Lee, Anthony M. D.; Wang, Hequn; Tang, Shuo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

2012-07-01

There are increased interests on using multiphoton imaging and spectroscopy for skin tissue characterization and diagnosis. However, most studies have been done with just a few excitation wavelengths. Our objective is to perform a systematic study of the two-photon fluorescence (TPF) properties of skin fluorophores, normal skin, and diseased skin tissues. A nonlinear excitation-emission-matrix (EEM) spectroscopy system with multiphoton imaging guidance was constructed. A tunable femtosecond laser was used to vary excitation wavelengths from 730 to 920 nm for EEM data acquisition. EEM measurements were performed on excised fresh normal skin tissues, seborrheic keratosis tissue samples, and skin fluorophores including: NADH, FAD, keratin, melanin, collagen, and elastin. We found that in the stratum corneum and upper epidermis of normal skin, the cells have large sizes and the TPF originates from keratin. In the lower epidermis, cells are smaller and TPF is dominated by NADH contributions. In the dermis, TPF is dominated by elastin components. The depth resolved EEM measurements also demonstrated that keratin structure has intruded into the middle sublayers of the epidermal part of the seborrheic keratosis lesion. These results suggest that the imaging guided TPF EEM spectroscopy provides useful information for the development of multiphoton clinical devices for skin disease diagnosis.

Non-invasive method for quantitative evaluation of exogenous compound deposition on skin.

PubMed

Stamatas, Georgios N; Wu, Jeff; Kollias, Nikiforos

2002-02-01

Topical application of active compounds on skin is common to both pharmaceutical and cosmetic industries. Quantification of the concentration of a compound deposited on the skin is important in determining the optimum formulation to deliver the pharmaceutical or cosmetic benefit. The most commonly used techniques to date are either invasive or not easily reproducible. In this study, we have developed a noninvasive alternative to these techniques based on spectrofluorimetry. A mathematical model based on diffusion approximation theory is utilized to correct fluorescence measurements for the attenuation caused by endogenous skin chromophore absorption. The limitation is that the compound of interest has to be either fluorescent itself or fluorescently labeled. We used the method to detect topically applied salicylic acid. Based on the mathematical model a calibration curve was constructed that is independent of endogenous chromophore concentration. We utilized the method to localize salicylic acid in epidermis and to follow its dynamics over a period of 3 d.

Thermal Transport Characteristics of Human Skin Measured In Vivo Using Ultrathin Conformal Arrays of Thermal Sensors and Actuators

PubMed Central

Webb, R. Chad; Pielak, Rafal M.; Bastien, Philippe; Ayers, Joshua; Niittynen, Juha; Kurniawan, Jonas; Manco, Megan; Lin, Athena; Cho, Nam Heon; Malyrchuk, Viktor; Balooch, Guive; Rogers, John A.

2015-01-01

Measurements of the thermal transport properties of the skin can reveal changes in physical and chemical states of relevance to dermatological health, skin structure and activity, thermoregulation and other aspects of human physiology. Existing methods for in vivo evaluations demand complex systems for laser heating and infrared thermography, or they require rigid, invasive probes; neither can apply to arbitrary regions of the body, offers modes for rapid spatial mapping, or enables continuous monitoring outside of laboratory settings. Here we describe human clinical studies using mechanically soft arrays of thermal actuators and sensors that laminate onto the skin to provide rapid, quantitative in vivo determination of both the thermal conductivity and thermal diffusivity, in a completely non-invasive manner. Comprehensive analysis of measurements on six different body locations of each of twenty-five human subjects reveal systematic variations and directional anisotropies in the characteristics, with correlations to the thicknesses of the epidermis (EP) and stratum corneum (SC) determined by optical coherence tomography, and to the water content assessed by electrical impedance based measurements. Multivariate statistical analysis establishes four distinct locations across the body that exhibit different physical properties: heel, cheek, palm, and wrist/volar forearm/dorsal forearm. The data also demonstrate that thermal transport correlates negatively with SC and EP thickness and positively with water content, with a strength of correlation that varies from region to region, e.g., stronger in the palmar than in the follicular regions. PMID:25658947

Thermal transport characteristics of human skin measured in vivo using ultrathin conformal arrays of thermal sensors and actuators.

PubMed

Webb, R Chad; Pielak, Rafal M; Bastien, Philippe; Ayers, Joshua; Niittynen, Juha; Kurniawan, Jonas; Manco, Megan; Lin, Athena; Cho, Nam Heon; Malyrchuk, Viktor; Balooch, Guive; Rogers, John A

2015-01-01

Measurements of the thermal transport properties of the skin can reveal changes in physical and chemical states of relevance to dermatological health, skin structure and activity, thermoregulation and other aspects of human physiology. Existing methods for in vivo evaluations demand complex systems for laser heating and infrared thermography, or they require rigid, invasive probes; neither can apply to arbitrary regions of the body, offers modes for rapid spatial mapping, or enables continuous monitoring outside of laboratory settings. Here we describe human clinical studies using mechanically soft arrays of thermal actuators and sensors that laminate onto the skin to provide rapid, quantitative in vivo determination of both the thermal conductivity and thermal diffusivity, in a completely non-invasive manner. Comprehensive analysis of measurements on six different body locations of each of twenty-five human subjects reveal systematic variations and directional anisotropies in the characteristics, with correlations to the thicknesses of the epidermis (EP) and stratum corneum (SC) determined by optical coherence tomography, and to the water content assessed by electrical impedance based measurements. Multivariate statistical analysis establishes four distinct locations across the body that exhibit different physical properties: heel, cheek, palm, and wrist/volar forearm/dorsal forearm. The data also demonstrate that thermal transport correlates negatively with SC and EP thickness and positively with water content, with a strength of correlation that varies from region to region, e.g., stronger in the palmar than in the follicular regions.

Inter- and intra-individual differences in skin hydration and surface lipids measured with mid-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Ezerskaia, A.; Pereira, S. F.; Urbach, H. P.; Varghese, B.

2016-03-01

Skin health is characterized by heterogeneous system of water and lipids in upper layers providing protection from external environment and preventing loss of vital components of the body. Skin hydration (moisture) and sebum (skin surface lipids) are considered to be important factors in skin health; a right balance between these components is an indication of healthy skin and plays a central role in protecting and preserving skin integrity. In this manuscript we present inter- and intra-individual variation in skin hydration and surface lipids measured with a home-built experimental prototype based on infrared spectroscopy. Results show good agreement with measurements performed by commercially available instruments Corneometer and Sebumeter used for skin hydration and sebum measurements respectively.

Measurement of skin dose from cone-beam computed tomography imaging.

PubMed

Akyalcin, Sercan; English, Jeryl D; Abramovitch, Kenneth M; Rong, Xiujiang J

2013-10-09

To measure surface skin dose from various cone-beam computed tomography (CBCT) scanners using point-dosimeters. A head anthropomorphic phantom was used with nanoDOT optically stimulated luminescence (OSL) dosimeters (Landauer Corp., Glenwood, IL) attached to various anatomic landmarks. The phantom was scanned using multiple exposure protocols for craniofacial evaluations in three different CBCT units and a conventional x-ray imaging system. The dosimeters were calibrated for each of the scan protocols on the different imaging systems. Peak skin dose and surface doses at the eye lens, thyroid, submandibular and parotid gland levels were measured. The measured skin doses ranged from 0.09 to 4.62 mGy depending on dosimeter positions and imaging systems. The average surface doses to the lens locations were ~4.0 mGy, well below the threshold for cataractogenesis (500 mGy). The results changed accordingly with x-ray tube output (mAs and kV) and also were sensitive to scan field of view (SFOV). As compared to the conventional panoramic and cephalometric imaging system, doses from all three CBCT systems were at least an order of magnitude higher. Peak skin dose and surface doses at the eye lens, thyroid, and salivary gland levels measured from the CBCT imaging systems were lower than the thresholds to induce deterministic effects. However, our findings do not justify the routine use of CBCT imaging in orthodontics considering the lifetime-attributable risk to the individual.

Measurement of skin dose from cone-beam computed tomography imaging

PubMed Central

2013-01-01

Objective To measure surface skin dose from various cone-beam computed tomography (CBCT) scanners using point-dosimeters. Materials & methods A head anthropomorphic phantom was used with nanoDOT optically stimulated luminescence (OSL) dosimeters (Landauer Corp., Glenwood, IL) attached to various anatomic landmarks. The phantom was scanned using multiple exposure protocols for craniofacial evaluations in three different CBCT units and a conventional x-ray imaging system. The dosimeters were calibrated for each of the scan protocols on the different imaging systems. Peak skin dose and surface doses at the eye lens, thyroid, submandibular and parotid gland levels were measured. Results The measured skin doses ranged from 0.09 to 4.62 mGy depending on dosimeter positions and imaging systems. The average surface doses to the lens locations were ~4.0 mGy, well below the threshold for cataractogenesis (500 mGy). The results changed accordingly with x-ray tube output (mAs and kV) and also were sensitive to scan field of view (SFOV). As compared to the conventional panoramic and cephalometric imaging system, doses from all three CBCT systems were at least an order of magnitude higher. Conclusions Peak skin dose and surface doses at the eye lens, thyroid, and salivary gland levels measured from the CBCT imaging systems were lower than the thresholds to induce deterministic effects. However, our findings do not justify the routine use of CBCT imaging in orthodontics considering the lifetime-attributable risk to the individual. PMID:24192155

Skin elasticity as a measure of radiation fibrosis: is it reproducible and does it correlate with patient and physician-reported measures?

PubMed

Nguyen, Nhu-Tram A; Roberge, David; Freeman, Carolyn R; Wong, Cindy; Hines, Jerod; Turcotte, Robert E

2014-10-01

Current means of measuring RT-induced fibrosis are subjective. We evaluated the DermaLab suction cup system to measure objectively skin deflection as a surrogate for fibrosis. Sixty-nine patients with E-STS were treated with limb-sparing surgery and 50-66 Grays (Gy) of RT. Using a "scleroderma" DermaLab Suction Cup, the skin stiffness was measured by two clinicians. The National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) scale, the Musculoskeletal Tumor Rating Scale (MSTS) and Toronto Extremity Salvage Score (TESS) questionnaires were completed for each patient. Levels of agreement between measurers were estimated using the Kappa (k) coefficient and the concordance correlation coefficient (CCC). All sixty-nine patients were included. The level of agreement between measurers for NCI-CTCAE grading was moderate (range k = 0.41-0.59). The CCC for the elasticity measurements were higher, with CCC = 0.82 for fibrotic skin and CCC 5 0.84 for normal skin. The elasticity measurements were significantly higher when MSTS scores were <30 and or TESS scores were <90. Suction Cup measurement of skin elasticity is more reproducible than CTCAE grading and shows promise in generating reproducible measurements for radiation-induced skin fibrosis. Furthermore, it correlates well with the MSTS and TESS.

Reduction of shading-derived artifacts in skin chromophore imaging without measurements or assumptions about the shape of the subject

NASA Astrophysics Data System (ADS)

Yoshida, Kenichiro; Nishidate, Izumi; Ojima, Nobutoshi; Iwata, Kayoko

2014-01-01

To quantitatively evaluate skin chromophores over a wide region of curved skin surface, we propose an approach that suppresses the effect of the shading-derived error in the reflectance on the estimation of chromophore concentrations, without sacrificing the accuracy of that estimation. In our method, we use multiple regression analysis, assuming the absorbance spectrum as the response variable and the extinction coefficients of melanin, oxygenated hemoglobin, and deoxygenated hemoglobin as the predictor variables. The concentrations of melanin and total hemoglobin are determined from the multiple regression coefficients using compensation formulae (CF) based on the diffuse reflectance spectra derived from a Monte Carlo simulation. To suppress the shading-derived error, we investigated three different combinations of multiple regression coefficients for the CF. In vivo measurements with the forearm skin demonstrated that the proposed approach can reduce the estimation errors that are due to shading-derived errors in the reflectance. With the best combination of multiple regression coefficients, we estimated that the ratio of the error to the chromophore concentrations is about 10%. The proposed method does not require any measurements or assumptions about the shape of the subjects; this is an advantage over other studies related to the reduction of shading-derived errors.

Effects of wall temperature on skin-friction measurements by oil-film interferometry

NASA Astrophysics Data System (ADS)

Bottini, H.; Kurita, M.; Iijima, H.; Fukagata, K.

2015-10-01

Wind-tunnel skin-friction measurements with thin-oil-film interferometry have been taken on an aluminum sample to investigate the effects of wall temperature on the accuracy of the technique. The sample has been flush-mounted onto a flat plate with an electric heater at its bottom and mirror-smooth temperature-sensitive paint sprayed on its top. The heater has varied the sample temperature from ambient to 328 K, and the paint has permitted wall temperature measurements on the same area of the skin-friction measurements and during the same test. The measured wall temperatures have been used to calculate the correct oil viscosities, and these viscosities and the constant nominal viscosity at 298 K have been used to calculate two different sets of skin-friction coefficients. These sets have been compared to each other and with theoretical values. This comparison shows that the effects of wall temperature on the accuracy of skin-friction measurements are sensible, and more so as wall temperature differs from 298 K. Nonetheless, they are effectively neutralized by the use of wall temperature measurements in combination with the correct oil viscosity-temperature law. In this regard, the special temperature-sensitive paint developed for this study shows advantages with respect to more traditional wall temperature measurement techniques.

Findings toward the miniaturization of a laser speckle contrast device for skin roughness measurements

NASA Astrophysics Data System (ADS)

Louie, Daniel C.; Tchvialeva, Lioudmilla; Zeng, Haishan; Lee, Tim K.

2017-02-01

Skin roughness is an important parameter in the characterization of skin and skin lesions, particularly for the purposes of skin cancer detection. Our group had previously constructed a laser speckle device that can detect the roughness in microrelief of the skin. This paper reports on findings made for the further miniaturization of our existing portably-sized device. These findings include the feasibility of adopting a laser diode without temperature control, and the use of a single CCD camera for detection. The coherence length of a laser is a crucial criterion for speckle measurements as it must be within a specific range. The coherence length of a commercial grade 405 nm laser diode was found to be of an appropriate length. Also, after a short warm-up period the coherence length of the laser was found to remain relatively stable, even without temperature control. Although the laser's temperature change during operation may affect its power output and the shape of its spectrum, these are only minor factors in speckle contrast measurements. Our second finding covers a calibration curve to relate speckle measurements to roughness using only parallel polarization from one CCD camera. This was created using experimental data from skin phantoms and tested on in-vivo skin. These improvements are important steps forward in the ongoing development of the laser speckle device, especially towards a clinical device to measure skin roughness and evaluate skin lesions.

Two-wavelength Raman detector for noninvasive measurements of carotenes and lycopene in human skin

NASA Astrophysics Data System (ADS)

Ermakov, Igor V.; Ermakova, Maia R.; Gellermann, Werner

2005-04-01

Carotenoids are an important part of the antioxidant system in human skin. Carotenoid molecules, provided by fruits and vegetables, are potent free radical quenchers that accumulate in the body. If not balanced by carotenoids and other antioxidants, free radicals may cause premature skin aging, oxidative cell damage, and even skin cancers. As carotenoids depletion may predispose a person to cancer or other disease, rapid and noninvasive measurement of carotenoid level in skin may be of preventive or diagnostic help. At the very least, such measurement can be used to obtain a biomarker for healthy levels of fruit and vegetable consumption. Recently we have developed noninvasive optical technique based on Raman spectroscopy. In this paper we describe compact optical detector for clinical applications that utilizes two-wavelength excitation. It selectively measures the two most prominent skin carotenoids found in the human skin, lycopene and carotenes. According to the medical literature, these two compounds may play different roles in the human body and be part of different tissue defense mechanisms. Dual-wavelength Raman measurements reveal significant differences in the carotenoid composition of different subjects.

[Study on objectively evaluating skin aging according to areas of skin texture].

PubMed

Shan, Gaixin; Gan, Ping; He, Ling; Sun, Lu; Li, Qiannan; Jiang, Zheng; He, Xiangqian

2015-02-01

Skin aging principles play important roles in skin disease diagnosis, the evaluation of skin cosmetic effect, forensic identification and age identification in sports competition, etc. This paper proposes a new method to evaluate the skin aging objectively and quantitatively by skin texture area. Firstly, the enlarged skin image was acquired. Then, the skin texture image was segmented by using the iterative threshold method, and the skin ridge image was extracted according to the watershed algorithm. Finally, the skin ridge areas of the skin texture were extracted. The experiment data showed that the average areas of skin ridges, of both men and women, had a good correlation with age (the correlation coefficient r of male was 0.938, and the correlation coefficient r of female was 0.922), and skin texture area and age regression curve showed that the skin texture area increased with age. Therefore, it is effective to evaluate skin aging objectively by the new method presented in this paper.

Quantitative assessment of combination bathing and moisturizing regimens on skin hydration in atopic dermatitis.

PubMed

Chiang, Charles; Eichenfield, Lawrence F

2009-01-01

Standard recommendations for skin care for patients with atopic dermatitis stress the importance of skin hydration and the application of moisturizers. However, objective data to guide recommendations regarding the optimal practice methods of bathing and emollient application are scarce. This study quantified cutaneous hydration status after various combination bathing and moisturizing regimens. Four bathing/moisturizer regimens were evaluated in 10 subjects, five pediatric subjects with atopic dermatitis and five subjects with healthy skin. The regimens consisted of bathing alone without emollient application, bathing and immediate emollient application, bathing and delayed application, and emollient application alone. Each regimen was evaluated in all subjects, utilizing a crossover design. Skin hydration was assessed with standard capacitance measurements. In atopic dermatitis subjects, emollient alone yielded a significantly (p < 0.05) greater mean hydration over 90 minutes (206.2% baseline hydration) than bathing with immediate emollient (141.6%), bathing and delayed emollient (141%), and bathing alone (91.4%). The combination bathing and emollient application regimens demonstrated hydration values at 90 minutes not significantly greater than baseline. Atopic dermatitis subjects had a decreased mean hydration benefit compared with normal skin subjects. Bathing without moisturizer may compromise skin hydration. Bathing followed by moisturizer application provides modest hydration benefits, though less than that of simply applying moisturizer alone.

The impact of epidermal melanin on objective measurements of human skin colour.

PubMed

Alaluf, Simon; Atkins, Derek; Barrett, Karen; Blount, Margaret; Carter, Nik; Heath, Alan

2002-04-01

Objective measurements of human skin colour were made with a tristimulus (L*a*b*) chromameter in a range of different ethnic skin types. These were compared with biochemical measurements of melanin content, melanin composition and melanosome size in skin biopsies obtained from the same sites. L*, a* and b* values were found to vary significantly with ethnicity. In general, constitutively dark skin types have lower L* values, higher a* values and higher b* values than constitutively light skin types. Total epidermal melanin content appears to be the primary determinant of L* values in human skin (r = -0.88; P < 0.00001), whilst melanosome size also has a significant but more subtle influence on L* values (r = -0.73; P < 0.00001). There is also a strong positive contribution to a* values from epidermal melanin (r = 0.66, P < 0.00001), which accounts for the ethnic variation in a* values observed in this study. Melanin is also a major contributor to b* values in lighter skin types (r = 0.71, P < 0.00001). However, this relationship breaks down in darker skin types where b* values actually reach a maximum and then decrease as the concentration of melanin in the skin increases. This appears to be because of optical masking of yellow light by high concentrations of melanin in the epidermis. Analysis of the relationships between L*, a* and b* values in human skin indicate that they are very closely interrelated, and suggest that the optical properties of melanin in the epidermis are very similar to those of a dye on a fabric substrate.

Hot Films on Ceramic Substrates for Measuring Skin Friction

NASA Technical Reports Server (NTRS)

Noffz, Greg; Leiser, Daniel; Bartlett, Jim; Lavine, Adrienne

2003-01-01

Hot-film sensors, consisting of a metallic film on an electrically nonconductive substrate, have been used to measure skin friction as far back as 1931. A hot film is maintained at an elevated temperature relative to the local flow by passing an electrical current through it. The power required to maintain the specified temperature depends on the rate at which heat is transferred to the flow. The heat transfer rate correlates to the velocity gradient at the surface, and hence, with skin friction. The hot-film skin friction measurement method is most thoroughly developed for steady-state conditions, but additional issues arise under transient conditions. Fabricating hot-film substrates using low-thermal-conductivity ceramics can offer advantages over traditional quartz or polyester-film substrates. First, a low conductivity substrate increases the fraction of heat convected away by the fluid, thus increasing sensitivity to changes in flow conditions. Furthermore, the two-part, composite nature of the substrate allows the installation of thermocouple junctions just below the hot film, which can provide an estimate of the conduction heat loss.

Use of primary cell cultures to measure the late effects in the skins of rhesus monkeys irradiated with protons

NASA Astrophysics Data System (ADS)

Cox, A. B.; Wood, D. H.; Lett, J. T.

Previous pilot investigations of the uses of primary cell cultures to study late damage in stem cells of the skin of the New Zealand white (NZW) rabbit and the rhesus monkey /1-3/, have been extended to individual monkeys exposed to 55 MeV protons. Protons of this energy have a larger range in tissue of (~2.6 cm) than the 32 MeV protons (~0.9 cm) to which the animals in our earlier studies had been exposed. Although the primary emphases in the current studies were improvement and simplification in the techniques and logistics of transportation of biopsies to a central analytical facility, comparison of the quantitative measurements obtained thus far for survival of stem cells in the skins from animals irradiated 21 years ago reveals that the effects of both proton energies are similar.

Histopathology of laser skin resurfacing

NASA Astrophysics Data System (ADS)

Thomsen, Sharon L.; Baldwin, Bonnie; Chi, Eric; Ellard, Jeff; Schwartz, Jon A.

1997-05-01

Pulsed carbon-dioxide laser skin resurfacing is a purportedly 'non-thermal' procedure enjoying wide application as a cosmetic treatment for skin wrinkles. Treatment success has been based on clinical assessments of skin smoothness. Skin lesions (1 cm2) created by one, two or three superimposed carbon-dioxide laser passes were placed on the backs of 28 'fuzzy' Harlan Sprague Dawley rats. The variable laser irradiation parameters included measured energies ranging from 112 to 387/pulse with pulse widths of 65 and 125 microseconds and a repetition rate of 8 Hz. The square, flat laser beam measured 3 mm2 at the focal point. The lesions were collected from 0 to 10 days after treatment for qualitative and quantitative histopathology. Thermal damage and treatment effect tended to increase in severity and, to a lesser extent, depth with increased delivery parameters. In acute lesions, the vacuolated and fragmented, desiccated and thermally coagulated epidermis was partially removed exposing the underlying thermally coagulated dermal collagen and cells. Epidermal and dermal necrosis and slough occurred between 24 to 72 hours after treatment. Epithelial regeneration originated from the adnexa and the lesion edges. Dermal fibrous scar formation began at 5 days below the regenerated epidermis and became more prominent at 7 and 10 days.

Correlation between near infrared spectroscopy and electrical techniques in measuring skin moisture content

NASA Astrophysics Data System (ADS)

Mohamad, M.; Sabbri, A. R. M.; Mat Jafri, M. Z.; Omar, A. F.

2014-11-01

Near infrared (NIR) spectroscopy technique serves as an important tool for the measurement of moisture content of skin owing to the advantages it has over the other techniques. The purpose of the study is to develop a correlation between NIR spectrometer with electrical conventional techniques for skin moisture measurement. A non-invasive measurement of moisture content of skin was performed on different part of human face and hand under control environment (temperature 21 ± 1 °C, relative humidity 45 ± 5 %). Ten healthy volunteers age between 21-25 (male and female) participated in this study. The moisture content of skin was measured using DermaLab® USB Moisture Module, Scalar Moisture Checker and NIR spectroscopy (NIRQuest). Higher correlation was observed between NIRQuest and Dermalab moisture probe with a coefficient of determination (R2) above 70 % for all the subjects. However, the value of R2 between NIRQuest and Moisture Checker was observed to be lower with the R2 values ranges from 51.6 to 94.4 %. The correlation of NIR spectroscopy technique successfully developed for measuring moisture content of the skin. The analysis of this correlation can help to establish novel instruments based on an optical system in clinical used especially in the dermatology field.

Relationship between skin color and solar elastosis in aged Asian skin: A colorimetric-pathologic correlation.

PubMed

Kim, Dai Hyun; Oh, Ga Na; Kwon, In Hyuk; Seo, Soo Hong; Kye, Young Chul; Ahn, Hyo Hyun

2017-10-01

Aged skin is reported to be associated with unattractive skin color changes and solar elastosis. However, comparative studies have not documented the possible correlation between the two factors. This study investigated the plausible relationship between the facial skin color of elderly Asians and solar elastosis. A total of 22 skin specimens were collected from 22 Korean patients who underwent cheek skin biopsies. Skin color was quantitatively measured using colorimetric photography techniques to produce CIE L*a*b* values; the degree of solar elastosis was quantifiably assessed using a histologic grading scale. These values were used to investigate a correlation between the CIE L*a*b* coordinates and solar elastosis grade. The solar elastosis grade increased according to patient age (r = 0.67, p = .0006). However, the extent of solar elastosis was not statistically correlated with the CIE L*a*b* values, including L*, a*, and b* (r = 0.02, p = .95; r = 0.15, p = 0.50; r = -0.07, p = 0.76, respectively). The results showed that the solar elastosis grade increased, according to patient age, because of cumulative actinic damage. However, colorimetric skin color data did not correlate with the degree of solar elastosis. Therefore, cutaneous color changes and solar elastosis are separate, age-related phenomena. Physicians should be aware of the possible histologic changes in actinically damaged facial skin, regardless of the skin color. © 2017 Wiley Periodicals, Inc.

Non-invasive laser Raman detection of lycopene and ž-carotene antioxidants in skin

NASA Astrophysics Data System (ADS)

Ermakov, Igor V.; Ermakova, Maia R.; Gellermann, Werner

2003-07-01

The predominant long-chain carotenoids found in the human skin are lycopene and β-carotene. They are powerful antioxidants and thought to act as scavengers for free radicals and single oxygen that are formed by excessive exposure of skin to sunlight. However the role of the particular representatives of the carotenoid antioxidants family in the skin defense mechanism is still unclear and has to be clarified. We demonstrate the opportunity for fast non-invasive selective quantitative detection of β-carotene and lycopene in human skin employing Raman spectroscopy. Analyzing Raman signals originating from the carbon-carbon double bond stretch vibrations of the molecules under blue and green laser excitation we were able to characterize quantitativly the concentrations of each carotenoid in alive human skin. In this method we take an advantage of different Raman cross-section spectral profile for β-carotene and lycopene molecules. This novel technique allows the quantitative assessment of individual carotenoid species in the skin rather then the cumulative level of long-chain carotenoids mixture as we could measure in our previous works. The required laser light exposure levels are well within safety standards. Prelimininary dichoromatic Raman measurements reveal significant differences in the carotenoid composition of different volunteer's skin: even in statistically small group of seven subjects the ratio of β-carotene-to-lycopene in their skin vary from 0.5 to 1.6. This technique holds promise as a method of rapid screening of carotenoids composition of human skin in large populations and suitable in clinical studies for assessing the risk for cutaneous diseases.

Electrode-Skin contact impedance: In vivo measurements on an ovine model

NASA Astrophysics Data System (ADS)

Nguyen, D. T.; Kosobrodov, R.; Barry, M. A.; Chik, W.; Jin, C.; Oh, T. I.; Thiagalingam, A.; McEwan, A.

2013-04-01

The problem of electrical impedance between the skin and the electrode is an on-going challenge in bio-electronics. This is particularly true in the case of Electrical Impedance Tomography (EIT), which uses a large number of skin-contact electrodes and is very sensitive to noise. In the present article, contact impedance is measured and compared for a range of electrodes placed on the thorax of an ovine model. The study has been approved by the Westmead Hospital Animal Ethics Committee. The electrode models that were employed in the research are Ag/AgCl electrodes (E1), commonly used for ECG and EIT measurements in both humans and animal models, stainless steel crocodile clips (E2), typically used on animal models, and novel multi-point dry electrodes in two modifications: bronze plated (E3) and nickel plated (E4). Further, since the contact impedance is mostly attributed to the acellular outer layer of the skin, in our experiment, we attempted to study the effect of this layer by comparing the results when the skin is intact and when electrodes are introduced underneath the skin through small cuts. This boundary effect was assessed by comparison of measurements obtained during E2 skin surface contact, and sub-cutaneous contact (E5). Twelve gauge intradermal needles were also tested as an electrode (E6). The full impedance spectrum, from 500 Hz to 300 kHz, was recorded, analysed and compared. As expected, the contact impedance in the more invasive cases, i.e the electrodes under the skin, is significantly lower than in the non-invasive cases. At the frequency of 50 kHz which is commonly used in lung EIT acquisition, electrodes E3, E4 and E6 demonstrated contact impedance of less than 200 Ω, compared to more than 400 Ω measured for electrodes E1, E2 and E5. In conclusion, the novel multipoint electrodes proved to be best suited for EIT purposes, because they are non-invasive and have lower contact impedance than Ag/AgCl and crocodile clips, in both invasive and

Quantitative second-harmonic generation imaging to detect osteogenesis imperfecta in human skin samples

NASA Astrophysics Data System (ADS)

Adur, J.; Ferreira, A. E.; D'Souza-Li, L.; Pelegati, V. B.; de Thomaz, A. A.; Almeida, D. B.; Baratti, M. O.; Carvalho, H. F.; Cesar, C. L.

2012-03-01

Osteogenesis Imperfecta (OI) is a genetic disorder that leads to bone fractures due to mutations in the Col1A1 or Col1A2 genes that affect the primary structure of the collagen I chain with the ultimate outcome in collagen I fibrils that are either reduced in quantity or abnormally organized in the whole body. A quick test screening of the patients would largely reduce the sample number to be studied by the time consuming molecular genetics techniques. For this reason an assessment of the human skin collagen structure by Second Harmonic Generation (SHG) can be used as a screening technique to speed up the correlation of genetics/phenotype/OI types understanding. In the present work we have used quantitative second harmonic generation (SHG) imaging microscopy to investigate the collagen matrix organization of the OI human skin samples comparing with normal control patients. By comparing fibril collagen distribution and spatial organization, we calculated the anisotropy and texture patterns of this structural protein. The analysis of the anisotropy was performed by means of the two-dimensional Discrete Fourier Transform and image pattern analysis with Gray-Level Co-occurrence Matrix (GLCM). From these results, we show that statistically different results are obtained for the normal and disease states of OI.

Genetic Algorithm for Opto-thermal Skin Hydration Depth Profiling Measurements

NASA Astrophysics Data System (ADS)

Cui, Y.; Xiao, Perry; Imhof, R. E.

2013-09-01

Stratum corneum is the outermost skin layer, and the water content in stratum corneum plays a key role in skin cosmetic properties as well as skin barrier functions. However, to measure the water content, especially the water concentration depth profile, within stratum corneum is very difficult. Opto-thermal emission radiometry, or OTTER, is a promising technique that can be used for such measurements. In this paper, a study on stratum corneum hydration depth profiling by using a genetic algorithm (GA) is presented. The pros and cons of a GA compared against other inverse algorithms such as neural networks, maximum entropy, conjugate gradient, and singular value decomposition will be discussed first. Then, it will be shown how to use existing knowledge to optimize a GA for analyzing the opto-thermal signals. Finally, these latest GA results on hydration depth profiling of stratum corneum under different conditions, as well as on the penetration profiles of externally applied solvents, will be shown.

Diffusing wave spectroscopy and its application for monitoring of skin blood microcirculation

NASA Astrophysics Data System (ADS)

Meglinski, Igor V.

2003-10-01

Diffusing Wave Spectroscopy (DWS) is a novel modern technique uniquely suited for the non-invasive measurements of the particles size and their motion within the randomly inhomogeneous highly scattering and absorbing media, including biological tissues as a human skin. The technique is based on the illuminating the media (tissues) with a coherent laser light, and analyzing the loss of coherence of the scattered field arises from motion of the scattering particles with respect to each other. Both theoretical and experimental results has shown the potentialities and viability of DWS application for the express non-invasive quantitative monitoring and functional diagnostics of skin blood microcirculation, with down to 1 μm/sec resolution. This is likely lead to quantitative monitoring in general diagnostics, diabetes studies, pharmacological intervention for the failing surgical skin flaps or replants, blood microcirculation monitoring during sepsis, assess burn depth, diagnose atherosclerotic disease, and investigate mechanisms of photodynamic therapy for cancer treatment. In frame of current report we describe the recent developments of DWS further to the point that skin blood micro-flow can be routinely and accurately obtained in a separate skin vascular bed on normal skin tissues.

Raman spectroscopic measurements of beta-carotene and lycopene in human skin

NASA Astrophysics Data System (ADS)

Darvin, M. E.; Gerzonde, I.; Ey, S.; Brandt, Nikolai N.; Albrecht, Hansjoerg; Gonchukov, Sergei A.; Sterry, Wolfram; Lademann, Juergen

2004-08-01

The antioxidant β-carotene and lycopene substances were detected non-invasively, in vivo in human skin using resonance Raman spectroscopy. Both substances were detected simultaneously. To distinguish between the substances, the Raman signals were excited at 488 nm and 514,5 nm simultaneously using a multilane Ar+ laser. The application of a fiber based optical imaging system allowed the detection of β-carotene and lycopene on any skin area. The disturbance of the measurements because of non-homogeneous skin pigmentation was avoided by using a measuring area of 28 mm2. The minimum power density for registration of the Raman signals and their optimum relation was determined. The Raman spectroscopic method is well suited for the evaluation of the efficacy of topically or systematically applied amounts of β-carotene and lycopene.

The importance of optical methods for non-invasive measurements in the skin care industry

NASA Astrophysics Data System (ADS)

Stamatas, Georgios N.

2010-02-01

Pharmaceutical and cosmetic industries are concerned with treating skin disease, as well as maintaining and promoting skin health. They are dealing with a unique tissue that defines our body in space. As such, skin provides not only the natural boundary with the environment inhibiting body dehydration as well as penetration of exogenous aggressors to the body, it is also ideally situated for optical measurements. A plurality of spectroscopic and imaging methods is being used to understand skin physiology and pathology and document the effects of topically applied products on the skin. The obvious advantage of such methods over traditional biopsy techniques is the ability to measure the cutaneous tissue in vivo and non-invasively. In this work, we will review such applications of various spectroscopy and imaging methods in skin research that is of interest the cosmetic and pharmaceutical industry. Examples will be given on the importance of optical techniques in acquiring new insights about acne pathogenesis and infant skin development.

Understanding effects of topical ingredients on electrical measurement of skin hydration.

PubMed

Crowther, J M

2016-12-01

Methods that assess skin hydration based on changes in its electrical properties are widely used in both cosmetic and medical research. However, the devices themselves often give results which are significantly different to each other. Although some work has previously been carried out to try and understand what these devices are actually reading, it was based on a technique for measuring the devices' responses to filter discs impregnated with different liquids, which could in itself be influencing the measurements. Presented here is a new method for measuring the devices' direct responses to different materials and solutions which removes any other confounding effects, thereby providing a clearer insight into their operation. The responses of a variety of different liquids and solutions were measured using the Corneometer ® and Skicon ® . A new method is presented, based on the use of a custom-designed PTFE block to hold the liquids, allowing their measurement without using a filter paper. This method was developed and tested against the existing filter paper-based approach. Differences were observed in results between filter paper- and PTFE block-based approach, indicating that the filter paper itself is capable of influencing the measurements and as such is not to be recommended for assessing how different liquids impact on results from the devices. A positive correlation was observed between Corneometer ® and Skicon ® readings for certain solutions and under certain conditions. A large influence of salt concentration was noted for the Skicon ® device with no or minimal impact from the actual water itself, humectants and emollients. Salts, emollients, water and humectants were observed to have an effect on Corneometer ® readings. Both the Corneometer ® and Skicon ® were influenced to different extents by chemicals other than water and therefore cannot be seen purely as measures of skin 'hydration'. Although there is strong evidence that the devices do

Skin friction measurements by a new nonintrusive double-laser-beam oil viscosity balance technique

NASA Technical Reports Server (NTRS)

Monson, D. J.; Higuchi, H.

1980-01-01

A portable dual-laser-beam interferometer that nonintrusively measures skin friction by monitoring the thickness change of an oil film subject to shear stress is described. The method is an advance over past versions in that the troublesome and error-introducing need to measure the distance to the oil leading edge and the starting time for the oil flow has been eliminated. The validity of the method was verified by measuring oil viscosity in the laboratory, and then using those results to measure skin friction beneath the turbulent boundary layer in a low-speed wind tunnel. The dual-laser-beam skin friction measurements are compared with Preston tube measurements, with mean velocity profile data in a 'law-of-the-wall' coordinate system, and with computations based on turbulent boundary-layer theory. Excellent agreement is found in all cases. This validation and the aforementioned improvements appear to make the present form of the instrument usable to measure skin friction reliably and nonintrusively in a wide range of flow situations in which previous methods are not practical.

Using a portable terahertz spectrometer to measure the optical properties of in vivo human skin

NASA Astrophysics Data System (ADS)

Echchgadda, Ibtissam; Grundt, Jessica A.; Tarango, Melissa; Ibey, Bennett L.; Tongue, Thomas; Liang, Min; Xin, Hao; Wilmink, Gerald J.

2013-12-01

Terahertz (THz) time-domain spectroscopy systems permit the measurement of a tissue's hydration level. This feature makes THz spectrometers excellent tools for the noninvasive assessment of skin; however, current systems are large, heavy and not ideal for clinical settings. We previously demonstrated that a portable, compact THz spectrometer permitted measurement of porcine skin optical properties that were comparable to those collected with conventional systems. In order to move toward human use of this system, the goal for this study was to measure the absorption coefficient (μa) and index of refraction (n) of human subjects in vivo. Spectra were collected from 0.1 to 2 THz, and measurements were made from skin at three sites: the palm, ventral and dorsal forearm. Additionally, we used a multiprobe adapter system to measure each subject's skin hydration levels, transepidermal water loss, and melanin concentration. Our results suggest that the measured optical properties varied considerably for skin tissues that exhibited dissimilar hydration levels. These data provide a framework for using compact THz spectrometers for clinical applications.

The colour of blood in skin: a comparison of Allen's test and photonics simulations.

PubMed

Välisuo, Petri; Kaartinen, Ilkka; Kuokkanen, Hannu; Alander, Jarmo

2010-11-01

The colour of the skin reflects many physiological and pathological states of an individual. Usually, the skin colour is examined by the bare eye alone. Several scaling systems have been developed to quantify the sensory evaluation of skin colour. In this work, the reflectance of the skin is measured directly using an objective instrument. Haemoglobin inside the dermal circulation is one of the key factors of skin colour and it also has a major role in the appearance of many skin lesions and scars. To quantitatively measure and analyse such conditions, the relation between the skin colour and the haemoglobin concentration in the skin needs to be resolved. To examine the effect of blood concentration on the skin colour, five Allen's tests were performed on 20 persons. The skin colour change was measured using a spectrophotometer by changing the blood concentration by the Allen's test. Light interaction with the skin was simulated with a Monte Carlo model, tuning the blood concentration parameter until the simulated and the measured spectra matched, yielding the relationship between the skin colour and the blood concentration. The simulation produced spectra similar to those measured. The change in the blood concentration in the simulation model and in the skin produced changes similar to the spectra. The reflectance of the skin was found to be a nonlinear function of the blood concentration. The relationship found between skin colour and blood concentration makes it possible to quantify those skin conditions expressed by blood volume better than plain colour. © 2010 John Wiley & Sons A/S.

Measurement of skin colors of world population and its application for preparing make-up products

NASA Astrophysics Data System (ADS)

Takata, Sadaki; Akimoto, Makio; Kawada, Kiyoshi; Takahashi, Motoji; Kumagai, Shigenori

2002-06-01

We attempted to analyze the skin color of women from the world using identical apparatuses and under identical conditions. The data was used for developing cosmetic products. The skin colors of a total of 1703 women over the world were measured to clarify the characteristics of skin color. Skin color measurement was done by using a spectrometric colorimeter. We modified the conventional erythema and melanin indices and established new respective indices which can reflect various spectral information of whole visible region. The present results were used to design new cosmetics in consideration of the optical properties of skin.

Optical Interferometric Measurement of Skin Vibration for the Diagnosis of Cardiovascular Diseases.

NASA Astrophysics Data System (ADS)

Hong, Hyundae

A system has been developed based on the measurement of skin surface vibration which is related to the underlying vascular wall motion for the superficial arteries and coronary movement for the chest wall. Data obtained suggests that the information detected by such measurements can be related to the derivative of the intravascular pressure, an important physiological parameter. These results are in contrast to conventional optical Doppler techniques which have been utilized to measure blood perfusion in the skin layers and blood flow within the superficial arteries. These techniques relied on the interaction between incident photons and moving red blood cells. The present system uses an optical interferometer with a 633 nm HeNe laser to detect μm displacements of the skin surface. A photodiode detects an optical Doppler shift signal of frequency, 2 v/ lambda, where v and lambda are the skin vibration velocity and the wavelength of the laser, respectively. The electronic processing system we developed enhances, cleans and processes the raw Doppler signal to produce two main outputs: Doppler audio, and a time domain profile of the skin velocity. The audio signal changes its tone according to the velocity of skin movement which is related to the first derivative of the intravascular pressure, and the internal structure of the intervening tissue layers between the vessel and the surface. The results obtained demonstrated that the skin velocity waveforms near each artery and the chest signals at the auscultation points for the four heart valve sounds were unique in their profiles. It also proved to be possible to measure the magnitude, harmonics, and the cardiovascular propagation delay for pulse waves. The theoretical and experimental results demonstrated that the system detected the skin velocity, which is related to the time derivative of the pressure. It also reduces the loading effect on the pulsation signals and heart sounds produced by the conventional

Quantitative analysis of four EMG amplifiers.

PubMed

Perreault, E J; Hunter, I W; Kearney, R E

1993-09-01

Four typical EMG amplifiers were tested quantitatively to observe the diversity and specificity of available equipment. Gain, phase, common mode rejection ratio (CMRR) and noise characteristics were measured for each device. Various gain and phase responses were observed, each best suited to specific application areas. For all amplifiers, the CMRR was shown to decrease dramatically in the presence of input impedance mismatches of more than 10 k omega between the two electrodes. Because such impedance mismatches are common on the skin surface, these results indicate that proper skin preparation is required to maximize the noise rejection capabilities of the tested amplifiers.

The relationship between dermal papillary structure and skin surface properties, color, and elasticity.

PubMed

Mizukoshi, K; Nakamura, T; Oba, A

2016-08-01

The skin contains an undulating structure called the dermal papillary structure between the border of the epidermis and dermis. The physiological importance of the dermal papillary structures has been discussed, however, the dermal papillary structures have never been evaluated for their contribution to skin appearance. In this study, we investigated the correlation between the dermal papillary structure and skin color and elasticity. In addition, the relationship was validated with skin model experiments. The dermal papillary structures in the skin of the female cheek were quantitatively measured by in vivo confocal laser scanning microscopy images. In addition, the skin color and elasticity were measured at the same site. A skin model with dermal papilla-like structures was created by referring to the optical and shape properties of the skin using agar gel and a scattering sheet. Correlations were found between the dermal papillary structures and skin color irregularity and skin elasticity. These relationships were verified by the experiments employing a skin model. The results of this study indicated that the dermal papillary structure is also an important factor for skin appearance such as color and elasticity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A device for the color measurement and detection of spots on the skin.

PubMed

Pladellorens, Josep; Pintó, Agustí; Segura, Jordi; Cadevall, Cristina; Antó, Joan; Pujol, Jaume; Vilaseca, Meritxell; Coll, Joaquín

2008-02-01

In this work, we present a new and fast easy-to-use device that allows the measurement of color and the detection of spots on the human skin. The developed device is highly practical for relatively untrained operators and uses inexpensive consumer equipment, such as a CCD color camera, a light source composed of LEDs and a laptop. The knowledge of the color of the skin and the detection of spots can be useful in several areas such as in dermatology applications, the cosmetics industry, the biometrics field, health care, etc. In order to perform these measurements the system takes a picture of the skin. After that, the operator selects the region of the skin to be analyzed on the displayed image and the system provides the CIELAB color coordinates, the chroma and the ITA parameter (Individual Tipology Angle), allowing the comparison with other reference images by means of CIELAB color differences. The system also detects spots, such as freckles, age spots, sunspots, pimples, black heads, etc., in a determined region, allowing the objective measurement of their size and area. The colorimetric information provided by a conventional spectrophotometer for the tested samples and the computed values obtained with the new developed system are quite similar, meaning that the developed system can be used to perform color measurements with relatively high accuracy. On the other hand, the feasibility of the system in order to detect and measure spots on the human skin has also been checked over a great amount of images, obtaining results with high precision. In this work, we present a new system that may be very useful in order to measure the color and to detect spots of the skin. Its portability and easy applicability will be very useful in dermatologic and cosmetic studies.

A paired comparison between human skin and hairless guinea pig skin in vitro permeability and lag time measurements for 6 industrial chemicals.

PubMed

Frasch, H Frederick; Barbero, Ana M

2009-01-01

The purpose of the present study was to measure and compare permeability coefficients (k(p)) and lag times (tau) in human skin and hairless guinea pig (HGP) skin. Paired experiments employed heat-separated epidermal membranes from human and HGP sources mounted on static in vitro diffusion cells. Infinite-dose, saturated aqueous solutions of 6 industrial chemicals were used as donors: aniline, benzene, 1,2- dichloroethane, diethyl phthalate, naphthalene, and tetrachloroethylene. No significant differences were found between human and HGP skin for either k(p) or tau for any of these chemicals (p >or= .24). HGP vs. human k(p) measurements, and HGP vs. human tau measurements, were highly correlated. For k(p), the slope of the linear correlation was close to unity (1.080 +/- 0.182) and the intercept close to 0 (0.015 +/- 0. 029 cm/h), with a correlation coefficient (r(2)) = 0.898. For tau, the slope was also close to unity (0.818 +/- 0.030) and the intercept close to 0 (-0.014 +/- 0.023 h), with r(2) = 0.994. These results suggest that HGP skin may serve as an excellent surrogate for human skin in in vitro dermal penetration studies.

Quantitative analysis of skin flap blood flow in the rat using laser Doppler velocimetry.

PubMed Central

Marks, N J

1985-01-01

Two experiments carried out on rat skin flaps are described, where microvascular flow has been measured noninvasively by a laser Doppler velocimeter. Using this technique it is possible to define the limits of an axial pattern flap in terms of microvascular flow; this was found to increase when the flap is elevated. 'Random-pattern' perfusion is defined by a fall in flow. This recovers sequentially along the flap, and at a constant rate at all sites. A differential in microvascular perfusion is thus maintained along a random-pattern flap for at least the first postoperative week. In a second experiment it is shown that there appears to be a linear relationship between the reduction in skin blood flow in a random-pattern flap and the distance from the base at which the measurements are made. It is suggested that these data support the view that the blood flow in a skin flap recovers primarily from its base rather than via peripheral neovascularization, and that this is due to vascular collaterals opening within the flap rather than to a relaxation of sympathetic tone. PMID:3156992

Ultrathin conformal devices for precise and continuous thermal characterization of human skin

NASA Astrophysics Data System (ADS)

Webb, R. Chad; Bonifas, Andrew P.; Behnaz, Alex; Zhang, Yihui; Yu, Ki Jun; Cheng, Huanyu; Shi, Mingxing; Bian, Zuguang; Liu, Zhuangjian; Kim, Yun-Soung; Yeo, Woon-Hong; Park, Jae Suk; Song, Jizhou; Li, Yuhang; Huang, Yonggang; Gorbach, Alexander M.; Rogers, John A.

2013-10-01

Precision thermometry of the skin can, together with other measurements, provide clinically relevant information about cardiovascular health, cognitive state, malignancy and many other important aspects of human physiology. Here, we introduce an ultrathin, compliant skin-like sensor/actuator technology that can pliably laminate onto the epidermis to provide continuous, accurate thermal characterizations that are unavailable with other methods. Examples include non-invasive spatial mapping of skin temperature with millikelvin precision, and simultaneous quantitative assessment of tissue thermal conductivity. Such devices can also be implemented in ways that reveal the time-dynamic influence of blood flow and perfusion on these properties. Experimental and theoretical studies establish the underlying principles of operation, and define engineering guidelines for device design. Evaluation of subtle variations in skin temperature associated with mental activity, physical stimulation and vasoconstriction/dilation along with accurate determination of skin hydration through measurements of thermal conductivity represent some important operational examples.

A study on electrode gels for skin conductance measurements.

PubMed

Tronstad, Christian; Johnsen, Gorm Krogh; Grimnes, Sverre; Martinsen, Ørjan G

2010-10-01

Low-frequency skin conductance is used within several clinical applications and is mainly sensitive to sweating and the moisture content of the stratum corneum, but also how electrodes introduce changes in the electrical properties. Four electrode gels were investigated with regard to sorption characteristics and electrical properties. Skin conductance time series were collected from 18 test subjects during relaxation, exercise and recovery, wearing different pairs of electrodes contralaterally on the hypothenar and the T9 dermatome. Pressure test was applied on the T9 electrodes. Impedance frequency sweeps were taken on the T9 electrodes the same day and the next, parameterized to the Cole model. ANOVA on the initial skin conductance level change, exercise response amplitude, recovery offset and pressure-induced changes revealed significant differences among gel types. The wetter gels caused a higher positive level change, a greater response amplitude, larger recovery offset and greater pressure-induced artifacts compared to the solid gels. Sweating on the T9 site led to negative skin conductance responses for the wetter gels. Correlations were found between the desorption measurements and the initial skin conductance level change (hypothenar: R = 0.988 T9: R = 0.901) RM-ANOVA on the Cole parameters revealed a significant decrease in R(s) of the most resistive gel. Clinical implications are discussed.

Measurement and effects of MOSKIN detectors on skin dose during high energy radiotherapy treatment.

PubMed

Alnawaf, Hani; Butson, Martin; Yu, Peter K N

2012-09-01

During in vivo dosimetry for megavoltage X-ray beams, detectors such as diodes, Thermo luminescent dosimeters (TLD's) and MOSFET devices are placed on the patient's skin. This of course will affect the skin dose delivered during that fraction of the treatment. Whilst the overall impact on increasing skin dose would be minimal, little has been quantified concerning the level of increase in absorbed dose, in vivo dosimeters produce when placed in the beams path. To this extent, measurements have been made and analysis performed on dose changes caused by MOSKIN, MOSFET, skin dose detectors. Maximum increases in skin dose were measured as 15 % for 6 MV X-rays and 10 % for 10 MV X-rays at the active crystal of the MOSKIN device which is the thickest part of the detector. This is compared to 32 and 26 % for a standard 1 mm thick LiF TLD at 10 × 10 cm(2) field size for 6 and 10 MV X-rays respectively. Radiochromic film, EBT2 has been shown to provide a high resolution 2 dimensional map of skin dose from these detectors and measures the effects of in vivo dosimeters used for radiotherapy dose assessment.

Simultaneous measurement of skin potential and conductance in electrodermal response monitoring

NASA Astrophysics Data System (ADS)

Jabbari, A.; Johnsen, B.; Grimnes, S.; Martinsen, Ø. G.

2010-04-01

Measurement of electrodermal activity (EDA) has been an important tool in psychophysiological research. The emotional sweat activity is very sensitive to psychological stimuli or conditions. The changes are easily detected by means of electrical measurements and since the sweat ducts are predominantly resistive, a low-frequency conductance measurement is appropriate for measurement of skin conductance in electrodermal response. The main purpose of this study was to develop a measuring system where DC current was replaced by a small AC current in a system so the DC potential and AC conductance could be measured simultaneously at the same skin site. A small, battery operated, PDA based instrument has been developed. The preliminary results of this ongoing study show that there is additional information in the DC potential channel and that different stimuli seem to produce slightly different response patterns.

Validity, Reliability, and Feasibility of Durometer Measurements of Scleroderma Skin Disease in a Multicenter Treatment Trial

PubMed Central

MERKEL, PETER A.; SILLIMAN, NANCY P.; DENTON, CHRISTOPHER P.; FURST, DANIEL E.; KHANNA, DINESH; EMERY, PAUL; HSU, VIVIEN M.; STREISAND, JAMES B.; POLISSON, RICHARD P.; ÅKESSON, ANITA; COPPOCK, JOHN; van den HOOGEN, FRANK; HERRICK, ARIANE; MAYES, MAUREEN D.; VEALE, DOUGLAS; SEIBOLD, JAMES R.; BLACK, CAROL M.; KORN, JOSEPH H.

2013-01-01

Objective To determine the validity, reliability, and feasibility of durometer measurements of skin hardness as an outcome measure in clinical trials of scleroderma. Methods Skin hardness was measured during a multicenter treatment trial for scleroderma using handheld digital durometers with a continuous scale. Skin thickness was measured by modified Rodnan skin score (MRSS). Other outcome data collected included the Scleroderma Health Assessment Questionnaire. In a reliability exercise in advance of the trial, 9 investigators examined the same 5 scleroderma patients by MRSS and durometry. Results Forty-three patients with early diffuse cutaneous systemic sclerosis were studied at 11 international centers (mean age 49 years [range 24–76], median disease duration 6.4 months [range 0.3–23], and median baseline MRSS 22 [range 11–38]). The reliability of durometer measurements was excellent, with high interobserver intraclass correlation coefficients (ICCs) (0.82–0.92), and each result was greater than the corresponding skin site ICCs for MRSS (0.54–0.85). Baseline durometer scores correlated well with MRSS (r = 0.69, P < 0.0001), patient self-assessments of skin disease (r = 0.69, P < 0.0001), and Health Assessment Questionnaire (HAQ) disability scores (r = 0.34, P = 0.03). Change in durometer scores correlated with change in MRSS (r = 0.70, P < 0.0001), change in patient self-assessments of skin disease (r = 0.52, P = 0.003), and change in HAQ disability scores (r = 0.42, P = 0.017). The effect size was greater for durometry than for MRSS or patient self-assessment. Conclusion Durometer measurements of skin hardness in patients with scleroderma are reliable, simple, accurate, demonstrate good sensitivity to change compared with traditional skin scoring, and reflect patients' self-assessments of their disease. Durometer measurements are valid, objective, and scalable, and should be considered for use as a complementary outcome measure to skin scoring in

Electrical measurement of the hydration state of the skin surface in vivo.

PubMed

Tagami, H

2014-09-01

Healthy skin surface is smooth and soft, because it is covered by the properly hydrated stratum corneum (SC), an extremely thin and soft barrier membrane produced by the underlying normal epidermis. By contrast, the skin surfaces covering pathological lesions exhibit dry and scaly changes and the SC shows poor barrier function. The SC barrier function has been assessed in vivo by instrumentally measuring transepidermal water loss (TEWL). However, there was a lack of any appropriate method for evaluating the hydration state of the skin surface in vivo until 1980 when we reported the feasibility of employing high-frequency conductance or capacitance to evaluate it quickly and accurately. With such measurements, we can assess easily the moisturizing efficacy of various topical agents in vivo as well as the distribution pattern of water in the SC by combining it with a serial tape-stripping procedure of the skin surface. © 2014 The Author BJD © 2014 British Association of Dermatologists.

Development and Measurement of Preschoolers' Quantitative Knowledge

ERIC Educational Resources Information Center

Geary, David C.

2015-01-01

The collection of studies in this special issue make an important contribution to our understanding and measurement of the core cognitive and noncognitive factors that influence children's emerging quantitative competencies. The studies also illustrate how the field has matured, from a time when the quantitative competencies of infants and young…

Using a portable terahertz spectrometer to measure the optical properties of in vivo human skin

NASA Astrophysics Data System (ADS)

Echchgadda, Ibtissam; Grundt, Jessica E.; Tarango, Melissa; Ibey, Bennett L.; Tongue, Thomas; Liang, Min; Xin, Hao; Wilmink, Gerald J.

2013-02-01

Terahertz time-domain spectroscopy (THz-TDS) systems are capable of detecting small differences in water concentration levels in biological tissues. This feature makes THz devices excellent tools for the noninvasive assessment of skin; however, most conventional systems prove too cumbersome for limited-space environments. We previously demonstrated that a portable, compact THz spectrometer permitted measurement of porcine skin optical properties that were comparable to those collected with conventional systems. In order to move toward human use of this system, the goal for this study was to collect the optical properties, specifically the absorption coefficient (μa) and index of refraction (n), of human subjects in vivo. Spectra were collected from 0.1-2 THz, and measurements were made on the palm, ventral (inner) and dorsal (outer) forearm. Prior to each THz measurement, we used a multiprobe adapter system to measure each subject's skin hydration levels, transepidermal waterloss (TEWL), skin color, and degree of melanin pigmentation. Our results suggest that the measured optical properties were wide-ranging, and varied considerably for skin tissues with different hydration and melanin levels. These data provide a novel framework for accurate human tissue measurements using THz spectrometers in limited-space environments.

Connecting qualitative observation and quantitative measurement for enhancing quantitative literacy in plant anatomy course

NASA Astrophysics Data System (ADS)

Nuraeni, E.; Rahmat, A.

2018-05-01

Forming of cognitive schemes of plant anatomy concepts is performed by processing of qualitative and quantitative data obtained from microscopic observations. To enhancing student’s quantitative literacy, strategy of plant anatomy course was modified by adding the task to analyze quantitative data produced by quantitative measurement of plant anatomy guided by material course. Participant in this study was 24 biology students and 35 biology education students. Quantitative Literacy test, complex thinking in plant anatomy test and questioner used to evaluate the course. Quantitative literacy capability data was collected by quantitative literacy test with the rubric from the Association of American Colleges and Universities, Complex thinking in plant anatomy by test according to Marzano and questioner. Quantitative literacy data are categorized according to modified Rhodes and Finley categories. The results showed that quantitative literacy of biology education students is better than biology students.

Measurement of conformability and adhesion energy of polymeric ultrathin film to skin model

NASA Astrophysics Data System (ADS)

Sugano, Junki; Fujie, Toshinori; Iwata, Hiroyasu; Iwase, Eiji

2018-06-01

We measured the conformability and adhesion energy of a polymeric ultrathin film “nanosheet” with hundreds of nanometer thickness to a skin model with epidermal depressions. To compare the confirmability of the nanosheets with different thicknesses and/or under different attaching conditions, we proposed a measurement method using skin models with the same surface profile and defined the surface strain εS as the quantified value of the conformability. Then, we measured the adhesion energy of the nanosheet at each conformability through a vertical tensile test. Experimental results indicate that the adhesion energy does not depend on the liquid used in wetting the nanosheet before attaching to the skin model and increases monotonously as the surface strain εS increases.

Impact of inflammation on iron stores in involved and non-involved psoriatic skin

NASA Astrophysics Data System (ADS)

Pinheiro, T.; Ynsa, M. D.; Alves, L. C.; Teixeira, P.; Ferreira, J.; Filipe, P.

2015-04-01

Accumulating evidence supports a role for cellular Fe in cell proliferation, inflammation, and disease tolerance. Psoriasis is a severe inflammatory and hyper proliferative condition of human skin whose aetiology remains poorly understood. Herein, we performed nuclear microscopy techniques to quantify with cellular resolution and high sensitivity the concentration of Fe in lesional (psoriatic plaques) and non-lesional adjacent skin of psoriatic patients. Fe contents were measured across skin depth and along epidermal strata either by quantitatively imaging Fe distribution in regions of interest, or by determining Fe profiles through analysis of sequential points along selected transepts. Both procedures require deconvolution of spectra to project quantitative elemental data through the application of different software codes. Using these approaches a detailed quantitative distribution of Fe was resolved. We show that in both lesional and non-lesional skin, the epidermal profiles of Fe contents showed a peak at the basal layer and that Fe concentration along the basal layer was not uniformly distributed. Typically, Fe levels were significantly higher in epidermal ridges relative to regions above dermal papillae. Lesional skin displayed excess Fe over extended regions above basal layer. In conclusion, we found significantly increased Fe deposits in the epidermis of psoriatic patients, particularly in areas of epidermal hyper proliferation. These findings suggest an important role for Fe in the pathogenesis of psoriasis. They also raise the possibility that manipulation of Fe levels in the skin may become relevant for the clinical management of psoriasis.

Combined use of laser Doppler flowmetry and skin thermometry for functional diagnostics of intradermal finger vessels.

PubMed

Zherebtsov, Evgeny A; Zherebtsova, Angelina I; Doronin, Alexander; Dunaev, Andrey V; Podmasteryev, Konstantin V; Bykov, Alexander; Meglinski, Igor

2017-04-01

We introduce a noninvasive diagnostic approach for functional monitoring of blood microflows in capillaries and thermoregulatory vessels within the skin. The measuring system is based on the combined use of laser Doppler flowmetry and skin contact thermometry. The obtained results suggest that monitoring of blood microcirculation during the occlusion, performed in conjunction with the skin temperature measurements in the thermally stabilized medium, has a great potential for quantitative assessment of angiospatic dysfunctions of the peripheral blood vessels. The indices of blood flow reserve and temperature response were measured and used as the primarily parameters of the functional diagnostics of the peripheral vessels of skin. Utilizing these parameters, a simple phenomenological model has been suggested to identify patients with angiospastic violations in the vascular system.

Combined use of laser Doppler flowmetry and skin thermometry for functional diagnostics of intradermal finger vessels

NASA Astrophysics Data System (ADS)

Zherebtsov, Evgeny A.; Zherebtsova, Angelina I.; Doronin, Alexander; Dunaev, Andrey V.; Podmasteryev, Konstantin V.; Bykov, Alexander; Meglinski, Igor

2017-04-01

We introduce a noninvasive diagnostic approach for functional monitoring of blood microflows in capillaries and thermoregulatory vessels within the skin. The measuring system is based on the combined use of laser Doppler flowmetry and skin contact thermometry. The obtained results suggest that monitoring of blood microcirculation during the occlusion, performed in conjunction with the skin temperature measurements in the thermally stabilized medium, has a great potential for quantitative assessment of angiospatic dysfunctions of the peripheral blood vessels. The indices of blood flow reserve and temperature response were measured and used as the primarily parameters of the functional diagnostics of the peripheral vessels of skin. Utilizing these parameters, a simple phenomenological model has been suggested to identify patients with angiospastic violations in the vascular system.

Cultured Skin Substitutes Reduce Donor Skin Harvesting for Closure of Excised, Full-Thickness Burns

PubMed Central

Boyce, Steven T.; Kagan, Richard J.; Yakuboff, Kevin P.; Meyer, Nicholas A.; Rieman, Mary T.; Greenhalgh, David G.; Warden, Glenn D.

2002-01-01

Objective Comparison of cultured skin substitutes (CSS) and split-thickness skin autograft (AG) was performed to assess whether donor-site harvesting can be reduced quantitatively and whether functional and cosmetic outcome is similar qualitatively in the treatment of patients with massive cutaneous burns. Summary Background Data Cultured skin substitutes consisting of collagen-glycosaminoglycan substrates populated with autologous fibroblasts and keratinocytes have been shown to close full-thickness skin wounds in preclinical and clinical studies with acceptable functional and cosmetic results. Methods Qualitative outcome was compared between CSS and AG in 45 patients on an ordinal scale (0, worst; 10, best) with primary analyses at postoperative day 28 and after about 1 year for erythema, pigmentation, pliability, raised scar, epithelial blistering, and surface texture. In the latest 12 of the 45 patients, tracings were performed of donor skin biopsies and wounds treated with CSS at postoperative days 14 and 28 to calculate percentage engraftment, the ratio of closed wound:donor skin areas, and the percentage of total body surface area closed with CSS. Results Measures of qualitative outcome of CSS or AG were not different statistically at 1 year after grafting. Engraftment at postoperative day 14 exceeded 75% in the 12 patients evaluated. The ratio of closed wound:donor skin areas for CSS at postoperative day 28 was significantly greater than for conventional 4:1 meshed autografts. The percentage of total body surface area closed with CSS at postoperative day 28 was significantly less than with AG. Conclusions The requirement for harvesting of donor skin for CSS was less than for conventional skin autografts. These results suggest that acute-phase recovery of patients with extensive burns is facilitated and that complications are reduced by the use of CSS together with conventional skin grafting. PMID:11807368

Cultured skin substitutes reduce donor skin harvesting for closure of excised, full-thickness burns.

PubMed

Boyce, Steven T; Kagan, Richard J; Yakuboff, Kevin P; Meyer, Nicholas A; Rieman, Mary T; Greenhalgh, David G; Warden, Glenn D

2002-02-01

Comparison of cultured skin substitutes (CSS) and split-thickness skin autograft (AG) was performed to assess whether donor-site harvesting can be reduced quantitatively and whether functional and cosmetic outcome is similar qualitatively in the treatment of patients with massive cutaneous burns. Cultured skin substitutes consisting of collagen-glycosaminoglycan substrates populated with autologous fibroblasts and keratinocytes have been shown to close full-thickness skin wounds in preclinical and clinical studies with acceptable functional and cosmetic results. Qualitative outcome was compared between CSS and AG in 45 patients on an ordinal scale (0, worst; 10, best) with primary analyses at postoperative day 28 and after about 1 year for erythema, pigmentation, pliability, raised scar, epithelial blistering, and surface texture. In the latest 12 of the 45 patients, tracings were performed of donor skin biopsies and wounds treated with CSS at postoperative days 14 and 28 to calculate percentage engraftment, the ratio of closed wound:donor skin areas, and the percentage of total body surface area closed with CSS. Measures of qualitative outcome of CSS or AG were not different statistically at 1 year after grafting. Engraftment at postoperative day 14 exceeded 75% in the 12 patients evaluated. The ratio of closed wound:donor skin areas for CSS at postoperative day 28 was significantly greater than for conventional 4:1 meshed autografts. The percentage of total body surface area closed with CSS at postoperative day 28 was significantly less than with AG. The requirement for harvesting of donor skin for CSS was less than for conventional skin autografts. These results suggest that acute-phase recovery of patients with extensive burns is facilitated and that complications are reduced by the use of CSS together with conventional skin grafting.

Electric Field Quantitative Measurement System and Method

NASA Technical Reports Server (NTRS)

Generazio, Edward R. (Inventor)

2016-01-01

A method and system are provided for making a quantitative measurement of an electric field. A plurality of antennas separated from one another by known distances are arrayed in a region that extends in at least one dimension. A voltage difference between at least one selected pair of antennas is measured. Each voltage difference is divided by the known distance associated with the selected pair of antennas corresponding thereto to generate a resulting quantity. The plurality of resulting quantities defined over the region quantitatively describe an electric field therein.

Warm layer and cool skin corrections for bulk water temperature measurements for air-sea interaction studies

NASA Astrophysics Data System (ADS)

Alappattu, Denny P.; Wang, Qing; Yamaguchi, Ryan; Lind, Richard J.; Reynolds, Mike; Christman, Adam J.

2017-08-01

The sea surface temperature (SST) relevant to air-sea interaction studies is the temperature immediately adjacent to the air, referred to as skin SST. Generally, SST measurements from ships and buoys are taken at depths varies from several centimeters to 5 m below the surface. These measurements, known as bulk SST, can differ from skin SST up to O(1°C). Shipboard bulk and skin SST measurements were made during the Coupled Air-Sea Processes and Electromagnetic ducting Research east coast field campaign (CASPER-East). An Infrared SST Autonomous Radiometer (ISAR) recorded skin SST, while R/V Sharp's Surface Mapping System (SMS) provided bulk SST from 1 m water depth. Since the ISAR is sensitive to sea spray and rain, missing skin SST data occurred in these conditions. However, SMS measurement is less affected by adverse weather and provided continuous bulk SST measurements. It is desirable to correct the bulk SST to obtain a good representation of the skin SST, which is the objective of this research. Bulk-skin SST difference has been examined with respect to meteorological factors associated with cool skin and diurnal warm layers. Strong influences of wind speed, diurnal effects, and net longwave radiation flux on temperature difference are noticed. A three-step scheme is established to correct for wind effect, diurnal variability, and then for dependency on net longwave radiation flux. Scheme is tested and compared to existing correction schemes. This method is able to effectively compensate for multiple factors acting to modify bulk SST measurements over the range of conditions experienced during CASPER-East.

Objective color measurements: clinimetric performance of three devices on normal skin and scar tissue.

PubMed

van der Wal, Martijn; Bloemen, Monica; Verhaegen, Pauline; Tuinebreijer, Wim; de Vet, Henrica; van Zuijlen, Paul; Middelkoop, Esther

2013-01-01

Color measurements are an essential part of scar evaluation. Thus, vascularization (erythema) and pigmentation (melanin) are common outcome parameters in scar research. The aim of this study was to investigate the clinimetric properties and clinical feasibility of the Mexameter, Colorimeter, and the DSM II ColorMeter for objective measurements on skin and scars. Fifty scars with a mean age of 6 years (2 months to 53 years) were included. Reliability was tested using the single-measure interobserver intraclass correlation coefficient. Validity was determined by measuring the Pearson correlation with the Fitzpatrick skin type classification (for skin) and the Patient and Observer Scar Assessment Scale (for scar tissue). All three instruments provided reliable readings (intraclass correlation coefficient ≥ 0.83; confidence interval: 0.71-0.90) on normal skin and scar tissue. Parameters with the highest correlations with the Fitzpatrick classification were melanin (Mexameter), 0.72; ITA (Colorimeter), -0.74; and melanin (DSM II), 0.70. On scars, the highest correlations with the Patient and Observer Scar Assessment Scale vascularization scores were the following: erythema (Mexameter), 0.59; LAB2 (Colorimeter), 0.69; and erythema (DSM II), 0.66. For hyperpigmentation, the highest correlations were melanin (Mexameter), 0.75; ITA (Colorimeter), -0.80; and melanin (DSM II), 0.83. This study shows that all three instruments can provide reliable color data on skin and scars with a single measurement. The authors also demonstrated that they can assist in objective skin type classification. For scar assessment, the most valid parameters in each instrument were identified.

Relations between acoustic cavitation and skin resistance during intermediate- and high-frequency sonophoresis.

PubMed

Rich, Kyle T; Hoerig, Cameron L; Rao, Marepalli B; Mast, T Douglas

2014-11-28

Enhanced skin permeability is known to be achieved during sonophoresis due to ultrasound-induced cavitation. However, the mechanistic role of cavitation during sonophoresis has been extensively investigated only for low-frequency (LFS, <100 kHz) applications. Here, mechanisms of permeability-enhancing stable and inertial cavitation were investigated by passively monitoring subharmonic and broadband emissions arising from cavitation isolated within or external to porcine skin in vitro during intermediate- (IFS, 100-700 kHz) and high-frequency sonophoresis (HFS, >1 MHz). The electrical resistance of skin, a surrogate measure of the permeability of skin to a variety of compounds, was measured to quantify the reduction and subsequent recovery of the skin barrier during and after exposure to pulsed (1 second pulse, 20% duty cycle) 0.41 and 2.0 MHz ultrasound over a range of acoustic powers (0-21.7 W) for 30 min. During IFS, significant skin resistance reductions and acoustic emissions from cavitation were measured exclusively when cavitation was isolated outside of the skin. Time-dependent skin resistance reductions measured during IFS correlated significantly with subharmonic and broadband emission levels. During HFS, significant skin resistance reductions were accompanied by significant acoustic emissions from cavitation measured during trials that isolated cavitation activity either outside of skin or within skin. Time-dependent skin resistance reductions measured during HFS correlated significantly greater with subharmonic than with broadband emission levels. The reduction of the skin barrier due to sonophoresis was reversible in all trials; however, effects incurred during IFS recovered more slowly and persisted over a longer period of time than HFS. These results quantitatively demonstrate the significance of cavitation during sonophoresis and suggest that the mechanisms and post-treatment longevity of permeability enhancement due to IFS and HFS treatments are

Ultrathin conformal devices for precise and continuous thermal characterization of human skin

PubMed Central

Webb, R. Chad; Bonifas, Andrew P.; Behnaz, Alex; Zhang, Yihui; Yu, Ki Jun; Cheng, Huanyu; Shi, Mingxing; Bian, Zuguang; Liu, Zhuangjian; Kim, Yun-Soung; Yeo, Woon-Hong; Park, Jae Suk; Song, Jizhou; Li, Yuhang; Huang, Yonggang; Gorbach, Alexander M.; Rogers, John A.

2013-01-01

Precision thermometry of the skin can, together with other measurements, provide clinically relevant information about cardiovascular health, cognitive state, malignancy and many other important aspects of human physiology. Here, we introduce an ultrathin, compliant skin-like sensor/actuator technology that can pliably laminate onto the epidermis to provide continuous, accurate thermal characterizations that are unavailable with other methods. Examples include non-invasive spatial mapping of skin temperature with millikelvin precision, and simultaneous quantitative assessment of tissue thermal conductivity. Such devices can also be implemented in ways that reveal the time-dynamic influence of blood flow and perfusion on these properties. Experimental and theoretical studies establish the underlying principles of operation, and define engineering guidelines for device design. Evaluation of subtle variations in skin temperature associated with mental activity, physical stimulation and vasoconstriction/dilation along with accurate determination of skin hydration through measurements of thermal conductivity represent some important operational examples. PMID:24037122

Quantitative Proteomic Profiling of Low-Dose Ionizing Radiation Effects in a Human Skin Model

PubMed Central

Hengel, Shawna M.; Aldrich, Joshua T.; Waters, Katrina M.; Pasa-Tolic, Ljiljana; Stenoien, David L.

2014-01-01

To assess responses to low-dose ionizing radiation (LD-IR) exposures potentially encountered during medical diagnostic procedures, nuclear accidents or terrorist acts, a quantitative proteomic approach was used to identify changes in protein abundance in a reconstituted human skin tissue model treated with 0.1 Gy of ionizing radiation. To improve the dynamic range of the assay, subcellular fractionation was employed to remove highly abundant structural proteins and to provide insight into radiation-induced alterations in protein localization. Relative peptide quantification across cellular fractions, control and irradiated samples was performing using 8-plex iTRAQ labeling followed by online two-dimensional nano-scale liquid chromatography and high resolution MS/MS analysis. A total of 107 proteins were detected with statistically significant radiation-induced change in abundance (>1.5 fold) and/or subcellular localization compared to controls. The top biological pathways identified using bioinformatics include organ development, anatomical structure formation and the regulation of actin cytoskeleton. From the proteomic data, a change in proteolytic processing and subcellular localization of the skin barrier protein, filaggrin, was identified, and the results were confirmed by western blotting. This data indicate post-transcriptional regulation of protein abundance, localization and proteolytic processing playing an important role in regulating radiation response in human tissues. PMID:28250387

Quantitative prediction of ionization effect on human skin permeability.

PubMed

Baba, Hiromi; Ueno, Yusuke; Hashida, Mitsuru; Yamashita, Fumiyoshi

2017-04-30

Although skin permeability of an active ingredient can be severely affected by its ionization in a dose solution, most of the existing prediction models cannot predict such impacts. To provide reliable predictors, we curated a novel large dataset of in vitro human skin permeability coefficients for 322 entries comprising chemically diverse permeants whose ionization fractions can be calculated. Subsequently, we generated thousands of computational descriptors, including LogD (octanol-water distribution coefficient at a specific pH), and analyzed the dataset using nonlinear support vector regression (SVR) and Gaussian process regression (GPR) combined with greedy descriptor selection. The SVR model was slightly superior to the GPR model, with externally validated squared correlation coefficient, root mean square error, and mean absolute error values of 0.94, 0.29, and 0.21, respectively. These models indicate that Log D is effective for a comprehensive prediction of ionization effects on skin permeability. In addition, the proposed models satisfied the statistical criteria endorsed in recent model validation studies. These models can evaluate virtually generated compounds at any pH; therefore, they can be used for high-throughput evaluations of numerous active ingredients and optimization of their skin permeability with respect to permeant ionization. Copyright © 2017 Elsevier B.V. All rights reserved.

Measuring the arterial-induced skin vibration by geometrical moiré fringe

NASA Astrophysics Data System (ADS)

Chiu, Shih-Yung; Wang, Chun-Hsiung; Lee, Shu-Sheng; Wu, Wen-Jong; Hsu, Yu-Hsiang; Lee, Chih-Kung

2018-02-01

The demand for self-measured blood pressure self-monitoring device has much increased due to cardiovascular diseases have become leading causes of death for aging population. Currently, the primary non-invasive blood pressure monitoring method is cuff-based. It is well developed and accurate. However, the measuring process is not comfortable, and it cannot provide a continuous measurement. To overcome this problem, methods such as tonometry, volume clamp method, photoplethysmography, pulse wave velocity, and pulse transit time are reported. However, the limited accuracy hindered its application for diagnostics. To perform sequential blood pressure measurement with a high accuracy and long-term examination, we apply moiré interferometry to measure wrist skin vibration induced by radial artery. To achieve this goal, we developed a miniaturized device that can perform moiré interferometry around the wrist region. The 0.4-mm-pitched binary grating and tattoo sticker with 0.46 mm-pitched stripe pattern are used to perform geometric moiré. We demonstrated that the sensitivity and accuracy of this integrated system were sufficient to monitor arterialinduced skin vibration non-invasively. Our developed system was validated with ECG signals collected by a commercial system. According to our studies from measurement, the repeatability of wrist pulsation measurement was achieved with an accuracy of 99.1% in heart rate. A good repeatability of wrist pulse measurement was achieved. Simulations and experiments are both conducted in this paper and prove of geometrical moiré method a suitable technique for arterial-induced skin vibration monitoring.

In vitro human skin permeation and decontamination of 2-chloroethyl ethyl sulfide (CEES) using Dermal Decontamination Gel (DDGel) and Reactive Skin Decontamination Lotion (RSDL).

PubMed

Cao, Yachao; Hui, Xiaoying; Zhu, Hanjiang; Elmahdy, Akram; Maibach, Howard

2018-07-01

This study compared the efficiency for in vitro human skin decontamination using DDGel and RSDL. Experiments were performed using in vitro human skin models, in which skin was mounted onto Flow-Through diffusion cells. The mass of 14 -C CEES removed from skin surface after decontamination was quantitated by measuring radioactivity with a liquid scintillation spectrometer. Both decontaminants removed more than 82% of CEES from skin. DDGel skin decontamination significantly reduced toxicant amount when compared to RSDL. Mean CEES remaining in stratum corneum (SC), viable epidermis, dermis, and systemic absorption of DDGel and RSDL were, 0.12 and 0.55% (P < 0.01), 0.31 and 0.95% (p < 0.01), 1.08 and 2.92% (p < 0.05), 3.13 and 6.34% (p < 0.05), respectively. DDGel showed higher decontamination efficiency (twice decontamination efficacy factor, DEF) than RSDL and efficiently removed chemicals from the skin surface, importantly back-extracted from the SC, and significantly reduced both chemical penetration into skin and systemic absorption. Thus, DDGel can offer a potential as a next generation skin decontamination platform technology for military and civilian applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Validation of image analysis techniques to measure skin aging features from facial photographs.

PubMed

Hamer, M A; Jacobs, L C; Lall, J S; Wollstein, A; Hollestein, L M; Rae, A R; Gossage, K W; Hofman, A; Liu, F; Kayser, M; Nijsten, T; Gunn, D A

2015-11-01

Accurate measurement of the extent skin has aged is crucial for skin aging research. Image analysis offers a quick and consistent approach for quantifying skin aging features from photographs, but is prone to technical bias and requires proper validation. Facial photographs of 75 male and 75 female North-European participants, randomly selected from the Rotterdam Study, were graded by two physicians using photonumeric scales for wrinkles (full face, forehead, crow's feet, nasolabial fold and upper lip), pigmented spots and telangiectasia. Image analysis measurements of the same features were optimized using photonumeric grades from 50 participants, then compared to photonumeric grading in the 100 remaining participants stratified by sex. The inter-rater reliability of the photonumeric grades was good to excellent (intraclass correlation coefficients 0.65-0.93). Correlations between the digital measures and the photonumeric grading were moderate to excellent for all the wrinkle comparisons (Spearman's rho ρ = 0.52-0.89) bar the upper lip wrinkles in the men (fair, ρ = 0.30). Correlations were moderate to good for pigmented spots and telangiectasia (ρ = 0.60-0.75). These comparisons demonstrate that all the image analysis measures, bar the upper lip measure in the men, are suitable for use in skin aging research and highlight areas of improvement for future refinements of the techniques. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons.

In vivo skin moisturizing measurement by high-resolution 3 Tesla magnetic resonance imaging.

PubMed

Mesrar, J; Ognard, J; Garetier, M; Chechin, D; Misery, L; Ben Salem, D

2017-08-01

Magnetic resonance imaging (MRI) is rarely used for the exploration of skin, even if studies have validated both feasibility of skin MRI and its interest for anatomical, physiological, and biochemical study of the skin. The purpose of this study is to explore moisturizing of the different skin layers using 3-T scan. An MRI of the heel's skin was performed using a 23 mm coil diameter on a 3T scan with a FFE (Fast Field Echo) 3D T1-weighted sequence and a TSE (Turbo Spin Echo) calculation T2-weighted sequence (pixels size of respectively 60 and 70 μm). This study was conducted on 35 healthy volunteers, who were scanned before applying moisturizer topic and 1 h after applying it. Region of interest in the stratum corneum, the epidermis and the dermis were generated on the T2 mapping. The thickness of each layer was measured. The T1 sequence allowed accurate cross-examination repositioning to ensure the comparability of the measurements. Among the 35 cases, two were excluded from the analysis because of movement artifacts. Measurements before and after moisturizer topic application displayed a T2 increase of 48.94% (P < 0.0001) in the stratum corneum and of 5.45% (P < 0.0001) in the epidermis yet without significant difference in the dermis. There was no significant link between the thickness of the stratum corneum and the T2 increase. However, there was a strong correlation between the thickness of the stratum corneum and the thickness of the epidermis (P < 0.001; rhô=0.72). High-resolution MRI allows fine exploration of anatomical and physiological properties of the skin and can further be used to extend the studies of skin hydration. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Quantitative analysis of macrophages in wound healing of rat skin subjected to loud noise stress.

PubMed

Rafi, Aisha; Khan, Muhammad Yunus; Minhas, Liaqat Ali

2014-01-01

Factors affecting skin wound healing have always been a central consideration in medical practice. Loud noise is biological stressor affecting the body systems at various levels. The present study was taken to study the effect of loud noise stress on the macrophages during wound healing process in male rat skin. One hundred and eighty male Sprague Dawley rats were randomly divided into control group-A and experimental group-B. Each group comprised 90 animals. Control and experimental groups were further subdivided into three subgroups of 30 animals each, corresponding to the day of sacrifice of animals, i.e., day 3, 5 and 7 after surgery. After induction of local anaesthesia a linear full thickness incision paravertebral to thoracic spine was made on the dorsum of rat. The experimental group B was exposed to loud noise stimulus (recorded noise of aero planes and gun fire) set at 97dBA to 102 dBA with a sound level meter. The animals were decapitated on day 3, 5 and 7 after surgery. Tissue was processed for paraffin embedding and stained by Hematoxylin and Eosin and Mallory's trichrome stain. Data was collected for the incisional space of the wound. Quantitative data of number of macrophages was analysed by Student's' test for the detection of any significant differences between the mean number in the experimental and control groups. All the quantitative data was expressed as means ± SE. A p-value of ≤ 0.05 was considered statistically significant. In this study macrophages were decreased statistically significantly at day 3 after surgery and thereafter increased significantly on day 5 and 7 after surgery in the experimental subgroups as compared to their match control subgroups. These results show that loud noise stress affects the cells (macrophages) involved in the healing of the wound therefore it is expected to have impact on the stages of wound healing.

Skin findings in Williams syndrome.

PubMed

Kozel, Beth A; Bayliss, Susan J; Berk, David R; Waxler, Jessica L; Knutsen, Russell H; Danback, Joshua R; Pober, Barbara R

2014-09-01

Previous examination in a small number of individuals with Williams syndrome (also referred to as Williams-Beuren syndrome) has shown subtly softer skin and reduced deposition of elastin, an elastic matrix protein important in tissue recoil. No quantitative information about skin elasticity in individuals with Williams syndrome is available; nor has there been a complete report of dermatologic findings in this population. To fill this knowledge gap, 94 patients with Williams syndrome aged 7-50 years were recruited as part of the skin and vascular elasticity (WS-SAVE) study. They underwent either a clinical dermatologic assessment by trained dermatologists (2010 WSA family meeting) or measurement of biomechanical properties of the skin with the DermaLab™ suction cup (2012 WSA family meeting). Clinical assessment confirmed that soft skin is common in this population (83%), as is premature graying of the hair (80% of those 20 years or older), while wrinkles (92%), and abnormal scarring (33%) were detected in larger than expected proportions. Biomechanical studies detected statistically significant differences in dP (the pressure required to lift the skin), dT (the time required to raise the skin through a prescribed gradient), VE (viscoelasticity), and E (Young's modulus) relative to matched controls. The RT (retraction time) also trended longer but was not significant. The biomechanical differences noted in these patients did not correlate with the presence of vascular defects also attributable to elastin insufficiency (vascular stiffness, hypertension, and arterial stenosis) suggesting the presence of tissue specific modifiers that modulate the impact of elastin insufficiency in each tissue. © 2014 Wiley Periodicals, Inc.

Altered expression of antimicrobial peptide genes in the skin of dogs with atopic dermatitis and other inflammatory skin conditions.

PubMed

Lancto, Cheryl A; Torres, Sheila M F; Hendrickson, Julie A; Martins, Kyra V; Rutherford, Mark S

2013-08-01

Reports indicate that human and canine patients with atopic dermatitis (AD) have reduced production of several skin antimicrobial peptides, but more recent data have called those results into question. To compare the mRNA expression of seven antimicrobial peptide genes in lesional and adjacent nonlesional skin biopsy specimens from dogs with AD with those from normal dogs and from dogs experiencing other inflammatory skin conditions. Normal dogs and patients with AD or other inflammatory skin conditions were enrolled with owner permission and approval of the Institutional Animal Care and Use Committee. Transcripts were measured by quantitative RT-PCR using a standard curve assessment. Normal transcript levels for all seven antimicrobial peptides varied depending on the body site assessed. Transcripts for secretory leukocyte proteinase inhibitor (SLPI) and skin-derived antileucoproteinase (SKALP; also known as elafin) were typically ~10-fold greater in number than transcripts for the canine β-defensins (CBD)-1, -102, -103, -122 and -124. Transcripts for SKALP, SLPI, CBD-1, CBD-103 and CBD-122 were lower in both lesional and adjacent nonlesional skin from dogs with AD in comparison to normal skin. Transcripts were reduced to a similar extent versus normal dogs in skin of dogs with inflammatory skin conditions from both lesional and nonlesional biopsies, except for CBD-122, which was reduced only in lesional skin. Compared with normal dog skin, transcripts for CBD-102 and CBD-124 were unaffected in dogs with AD. Both SKALP and SLPI may be important contributors to skin innate immunity, but their decreased expression in AD patients does not account for increased skin infections compared with other skin conditions. © 2013 The Authors. Veterinary Dermatology © 2013 ESVD and ACVD.

Biophysical effects of repetitive removal of adhesive dressings on peri-ulcer skin.

PubMed

Zillmer, R; Agren, M S; Gottrup, F; Karlsmark, T

2006-05-01

To study the effect of repeated removal of four different adhesive dressings on peri-ulcer skin using quantitative non-invasive techniques. Forty-five patients with open (n = 29) or healed (n = 16) venous leg ulcers were included. Peri-ulcer skin was treated for 14 days with patches of two different hydrocolloid-based adhesive dressings, one polyurethane adhesive and one soft silicone adhesive dressing. Normal skin of the patients' ventral forearm was also treated identically. Adhesive patches of the dressings were replaced every second day. The skin barrier function was assessed by measuring transepidermal water loss and stratum corneum hydration by measuring electrical conductance. Thirty-nine patients completed the study. The hydrocolloid adhesives increased transepidermal water loss and conductance while the polyurethane and soft silicone adhesives did not influence these parameters significantly compared with adjacent non-treated peri-ulcer skin. For normal forearm skin, similar relative effects among the four adhesives were found. Repetitive treatment with hydrocolloid-based adhesive dressings induced major functional alterations of the stratum corneum. In contrast, a polyurethane adhesive and a soft silicone adhesive dressing did not alter transepidermal water loss or conductance of peri-ulcer skin.

21 CFR 882.1540 - Galvanic skin response measurement device.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Galvanic skin response measurement device. 882.1540 Section 882.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1540...

Tissue viability imaging for quantification of skin erythema and blanching

NASA Astrophysics Data System (ADS)

Nilsson, Gert E.; Leahy, Martin J.

2010-02-01

Naked eye observation has up to recently been the main method of determining skin erythema (vasodilatation) and blanching (vasoconstriction) in skin testing. Since naked eye observation is a highly subjective and investigatordependent method, it is difficult to attain reproducibility and to compare results reported by different researchers performing their studies at different laboratories. Consequently there is a need for more objective, quantitative and versatile methods in the assessment of alterations in skin erythema and blanching caused by internal and external factors such as the intake of vasoactive drugs, application of agents on the skin surface and by constituents in the environment. Since skin microcirculation is sensitive to applied pressure and heat, such methods should preferably be noninvasive and designed for remote use without touching the skin. As skin microcirculation further possesses substantial spatial variability, imaging techniques are to be preferred before single point measurements. An emerging technology based on polarization digital camera spectroscopy - Tissue Viability Imaging (TiVi) - fulfills these requirements. The principles of TiVi (1) and some of its early applications (2-5) are addressed in this paper.

[Assessment of skin aging grading based on computer vision].

PubMed

Li, Lingyu; Xue, Jinxia; He, Xiangqian; Zhang, Sheng; Fan, Chu

2017-06-01

Skin aging is the most intuitive and obvious sign of the human aging processes. Qualitative and quantitative determination of skin aging is of particular importance for the evaluation of human aging and anti-aging treatment effects. To solve the problem of subjectivity of conventional skin aging grading methods, the self-organizing map (SOM) network was used to explore an automatic method for skin aging grading. First, the ventral forearm skin images were obtained by a portable digital microscope and two texture parameters, i.e. , mean width of skin furrows and the number of intersections were extracted by image processing algorithm. Then, the values of texture parameters were taken as inputs of SOM network to train the network. The experimental results showed that the network achieved an overall accuracy of 80.8%, compared with the aging grading results by human graders. The designed method appeared to be rapid and objective, which can be used for quantitative analysis of skin images, and automatic assessment of skin aging grading.

SU-F-T-151: Measurement Evaluation of Skin Dose in Scanning Proton Beam Therapy for Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, J; Nichols, E; Strauss, D

Purpose: To measure the skin dose and compare it with the calculated dose from a treatment planning system (TPS) for breast cancer treatment using scanning proton beam therapy (SPBT). Methods: A single en-face-beam SPBT plan was generated by a commercial TPS for two breast cancer patients. The treatment volumes were the entire breasts (218 cc and 1500 cc) prescribed to 50.4 Gy (RBE) in 28 fractions. A range shifter of 5 cm water equivalent thickness was used. The organ at risk (skin) was defined to be 5 mm thick from the surface. The skin doses were measured in water withmore » an ADCL calibrated parallel plate (PP) chamber. The measured data were compared with the values calculated in the TPS. Skin dose calculations can be subject to uncertainties created by the definition of the external contour and the limitations of the correction based algorithms, such as proton convolution superposition. Hence, the external contours were expanded by 0, 3 mm and 1 cm to include additional pixels for dose calculation. In addition, to examine the effects of the cloth gown on the skin dose, the skin dose measurements were conducted with and without gown. Results: On average the measured skin dose was 4% higher than the calculated values. At deeper depths, the measured and calculated doses were in better agreement (< 2%). Large discrepancy occur for the dose calculated without external expansion due to volume averaging. The addition of the gown only increased the measured skin dose by 0.4%. Conclusion: The implemented TPS underestimated the skin dose for breast treatments. Superficial dose calculation without external expansion would result in large errors for SPBT for breast cancer.« less

Quantitative measures for redox signaling.

PubMed

Pillay, Ché S; Eagling, Beatrice D; Driscoll, Scott R E; Rohwer, Johann M

2016-07-01

Redox signaling is now recognized as an important regulatory mechanism for a number of cellular processes including the antioxidant response, phosphokinase signal transduction and redox metabolism. While there has been considerable progress in identifying the cellular machinery involved in redox signaling, quantitative measures of redox signals have been lacking, limiting efforts aimed at understanding and comparing redox signaling under normoxic and pathogenic conditions. Here we have outlined some of the accepted principles for redox signaling, including the description of hydrogen peroxide as a signaling molecule and the role of kinetics in conferring specificity to these signaling events. Based on these principles, we then develop a working definition for redox signaling and review a number of quantitative methods that have been employed to describe signaling in other systems. Using computational modeling and published data, we show how time- and concentration- dependent analyses, in particular, could be used to quantitatively describe redox signaling and therefore provide important insights into the functional organization of redox networks. Finally, we consider some of the key challenges with implementing these methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Quantification of texture match of the skin graft: function and morphology of the stratum corneum.

PubMed

Inoue, K; Matsumoto, K

1986-01-01

In an attempt to analyze the "texture match" of grafted skin, functional and morphological aspects of the stratum corneum were studied using the Skin Surface Hydrometer (IBS Inc.) and the scanning electron microscope. The results showed that hygroscopicity and water holding capacity of the stratum corneum played a crucial role in making the skin surface soft and smooth. Morphologically there were regional differences in the surface pattern and the mean area of corneocytes, suggesting that these differences affect skin texture. It is suggested that the present functional and morphological studies of the stratum corneum can provide a quantitative measure of the "texture match".

The Relationship between Quantitative and Qualitative Measures of Writing Skills.

ERIC Educational Resources Information Center

Howerton, Mary Lou P.; And Others

The relationships of quantitative measures of writing skills to overall writing quality as measured by the E.T.S. Composition Evaluation Scale (CES) were examined. Quantitative measures included indices of language productivity, vocabulary diversity, spelling, and syntactic maturity. Power of specific indices to account for variation in overall…

Quantitative Determination of α-Arbutin, β-Arbutin, Kojic Acid, Nicotinamide, Hydroquinone, Resorcinol, 4-Methoxyphenol, 4-Ethoxyphenol, and Ascorbic Acid from Skin Whitening Products by HPLC-UV.

PubMed

Wang, Yan-Hong; Avonto, Cristina; Avula, Bharathi; Wang, Mei; Rua, Diego; Khan, Ikhlas A

2015-01-01

An HPLC-UV method was developed for the quantitative analysis of nine skin whitening agents in a single injection. These compounds are α-arbutin, β-arbutin, kojic acid, nicotinamide, resorcinol, ascorbic acid, hydroquinone, 4-methoxyphenol, and 4-ethoxyphenol. The separation was achieved on a reversed-phase C18 column within 30 min. The mobile phase was composed of water and methanol, both containing 0.1% acetic acid (v/v). The stability of the analytes was evaluated at different pH values between 2.3 and 7.6, and the extraction procedure was validated for different types of skin whitening product matrixes, which included two creams, a soap bar, and a capsule. The best solvent system for sample preparation was 20 mM NaH2PO4 containing 10% methanol at pH 2.3. The analytical method was validated for accuracy, precision, LOD, and LOQ. The developed HPLC-UV method was applied for the quantitation of the nine analytes in 59 skin whitening products including creams, lotions, sera, foams, gels, mask sheets, soap bars, tablets, and capsules.

Temperature measurements during laser skin welding

NASA Astrophysics Data System (ADS)

Fried, Nathaniel M.; Choi, Bernard; Welch, Ashley J.; Walsh, Joseph T., Jr.

1999-06-01

A thermal camera was used to measure surface temperatures during laser skin welding to provide feedback for optimization of the laser parameters. Two-cm-long, full- thickness incisions were made in guinea pig skin. India ink was used as an absorber. Continuous-wave, 1.06-μm, Nd:YAG laser radiation was scanned over the incisions, producing a pulse duration of approximately 100 ms. Cooling durations between scans of 1.6, 4.0, and 8.0 s were studied with total operation times of 3, 5, and 10 min, respectively. A laser spot diameter of 5 mm was used with the power constant at 10 W. Thermal images were obtained at 30 frames per second with a thermal camera detecting 3.5 micrometers radiation. Surface temperatures were recorded at 0, 1, and 6 mm from the center line of the incision. Cooling durations between scans of 1.6 s and 4.0 s in vitro resulted in temperatures at the weld site remaining above ~65°C for prolonged periods of time. Cooling durations between scans as long as 8.0 s were sufficient both in vitro and in vivo to prevent a significant rise in baseline temperatures at the weld site over time.

In vivo measurements of skin barrier: comparison of different methods and advantages of laser scanning microscopy

NASA Astrophysics Data System (ADS)

Patzelt, A.; Sterry, W.; Lademann, J.

2010-12-01

A major function of the skin is to provide a protective barrier at the interface between external environment and the organism. For skin barrier measurement, a multiplicity of methods is available. As standard methods, the determination of the transepidermal water loss (TEWL) as well as the measurement of the stratum corneum hydration, are widely accepted, although they offer some obvious disadvantages such as increased interference liability. Recently, new optical and spectroscopic methods have been introduced to investigate skin barrier properties in vivo. Especially, laser scanning microscopy has been shown to represent an excellent tool to study skin barrier integrity in many areas of relevance such as cosmetology, occupation, diseased skin, and wound healing.

Methodology for diagnosing of skin cancer on images of dermatologic spots by spectral analysis.

PubMed

Guerra-Rosas, Esperanza; Álvarez-Borrego, Josué

2015-10-01

In this paper a new methodology for the diagnosing of skin cancer on images of dermatologic spots using image processing is presented. Currently skin cancer is one of the most frequent diseases in humans. This methodology is based on Fourier spectral analysis by using filters such as the classic, inverse and k-law nonlinear. The sample images were obtained by a medical specialist and a new spectral technique is developed to obtain a quantitative measurement of the complex pattern found in cancerous skin spots. Finally a spectral index is calculated to obtain a range of spectral indices defined for skin cancer. Our results show a confidence level of 95.4%.

Advanced NDE techniques for quantitative characterization of aircraft

NASA Technical Reports Server (NTRS)

Heyman, Joseph S.; Winfree, William P.

1990-01-01

Recent advances in nondestructive evaluation (NDE) at NASA Langley Research Center and their applications that have resulted in quantitative assessment of material properties based on thermal and ultrasonic measurements are reviewed. Specific applications include ultrasonic determination of bolt tension, ultrasonic and thermal characterization of bonded layered structures, characterization of composite materials, and disbonds in aircraft skins.

A nonintrusive laser interferometer method for measurement of skin friction

NASA Technical Reports Server (NTRS)

Monson, D. J.

1982-01-01

A method is described for monitoring the changing thickness of a thin oil film subject to an aerodynamic shear stress using two focused laser beams. The measurement is then simply analyzed in terms of the surface skin friction of the flow. The analysis includes the effects of arbitrarily large pressure and skin friction gradients, gravity, and time varying oil temperature. It may also be applied to three dimensional flows with unknown direction. Applications are presented for a variety of flows including two dimensional flows, three dimensional swirling flows, separated flow, supersonic high Reynolds number flows, and delta wing vortical flows.

Better understanding of digital photography for skin color measurement: With a special emphasis on light characteristics.

PubMed

Seo, Soo Hong; Kim, Jae Hwan; Kim, Ji Woong; Kye, Young Chul; Ahn, Hyo Hyun

2011-02-01

Digital photography can be used to measure skin color colorimetrically when combined with proper techniques. To better understand the settings of digital photography for the evaluation and measurement of skin colors, we used a tungsten lamp with filters and the custom white balance (WB) function of a digital camera. All colored squares on a color chart were photographed with each original and filtered light, analyzed into CIELAB coordinates to produce the calibration method for each given light setting, and compared statistically with reference coordinates obtained using a reflectance spectrophotometer. They were summarized as to the typical color groups, such as skin colors. We compared these results according to the fixed vs. custom WB of a digital camera. The accuracy of color measurement was improved when using light with a proper color temperature conversion filter. The skin colors from color charts could be measured more accurately using a fixed WB. In vivo measurement of skin color was easy and possible with our method and settings. The color temperature conversion filter that produced daylight-like light from the tungsten lamp was the best choice when combined with fixed WB for the measurement of colors and acceptable photographs. © 2010 John Wiley & Sons A/S.

SU-E-I-06: Measurement of Skin Dose from Dental Cone-Beam CT Scans.

PubMed

Akyalcin, S; English, J; Abramovitch, K; Rong, J

2012-06-01

To directly measure skin dose using point-dosimeters from dental cone-beam CT (CBCT) scans. To compare the results among three different dental CBCT scanners and compare the CBCT results with those from a conventional panoramic and cephalomic dental imaging system. A head anthropomorphic phantom was used with nanoDOT dosimeters attached to specified anatomic landmarks of selected radiosensitive tissues of interest. To ensure reliable measurement results, three dosimeters were used for each location. The phantom was scanned under various modes of operation and scan protocols for typical dental exams on three dental CBCT systems plus a conventional dental imaging system. The Landauer OSL nanoDOT dosimeters were calibrated under the same imaging condition as the head phantom scan protocols, and specifically for each of the imaging systems. Using nanoDOT dosimeters, skin doses at several positions on the surface of an adult head anthropomorphic phantom were measured for clinical dental imaging. The measured skin doses ranged from 0.04 to 4.62mGy depending on dosimeter positions and imaging systems. The highest dose location was at the parotid surface for all three CBCT scanners. The surface doses to the locations of the eyes were ∼4.0mGy, well below the 500mGy threshold for possibly causing cataract development. The results depend on x-ray tube output (kVp and mAs) and also are sensitive to SFOV. Comparing to the conventional dental imaging system operated in panoramic and cephalometric modes, doses from all three CBCT systems were at least an order of magnitude higher. No image artifact was caused by presence of nanoDOT dosimeters in the head phantom images. Direct measurements of skin dose using nanoDOT dosimeters provided accurate skin dose values without any image artifacts. The results of skin dose measurements serve as dose references in guiding future dose optimization efforts in dental CBCT imaging. © 2012 American Association of Physicists in Medicine.

SILAC-based quantitative proteomic analysis reveals widespread molecular alterations in human skin keratinocytes upon chronic arsenic exposure.

PubMed

Mir, Sartaj Ahmad; Pinto, Sneha M; Paul, Somnath; Raja, Remya; Nanjappa, Vishalakshi; Syed, Nazia; Advani, Jayshree; Renuse, Santosh; Sahasrabuddhe, Nandini A; Prasad, T S Keshava; Giri, Ashok K; Gowda, Harsha; Chatterjee, Aditi

2017-03-01

Chronic exposure to arsenic is associated with dermatological and nondermatological disorders. Consumption of arsenic-contaminated drinking water results in accumulation of arsenic in liver, spleen, kidneys, lungs, and gastrointestinal tract. Although arsenic is cleared from these sites, a substantial amount of residual arsenic is left in keratin-rich tissues including skin. Epidemiological studies suggest the association of skin cancer upon arsenic exposure, however, the mechanism of arsenic-induced carcinogenesis is not completely understood. We developed a cell line based model to understand the molecular mechanisms involved in arsenic-mediated toxicity and carcinogenicity. Human skin keratinocyte cell line, HaCaT, was chronically exposed to 100 nM sodium arsenite over a period of 6 months. We observed an increase in basal ROS levels in arsenic-exposed cells. SILAC-based quantitative proteomics approach resulted in identification of 2111 proteins of which 42 proteins were found to be overexpressed and 54 downregulated (twofold) upon chronic arsenic exposure. Our analysis revealed arsenic-induced overexpression of aldo-keto reductase family 1 member C2 (AKR1C2), aldo-keto reductase family 1 member C3 (AKR1C3), glutamate-cysteine ligase catalytic subunit (GCLC), and NAD(P)H dehydrogenase [quinone] 1 (NQO1) among others. We observed downregulation of several members of the plakin family including periplakin (PPL), envoplakin (EVPL), and involucrin (IVL) that are essential for terminal differentiation of keratinocytes. MRM and Western blot analysis confirmed differential expression of several candidate proteins. Our study provides insights into molecular alterations upon chronic arsenic exposure on skin. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical applicability domain of the local lymph node assay (LLNA) for skin sensitisation potency. Part 4. Quantitative correlation of LLNA potency with human potency.

PubMed

Roberts, David W; Api, Anne Marie

2018-07-01

Prediction of skin sensitisation potential and potency by non-animal methods is the target of many active research programmes. Although the aim is to predict sensitisation potential and potency in humans, data from the murine local lymph node assay (LLNA) constitute much the largest source of quantitative data on in vivo skin sensitisation. The LLNA has been the preferred in vivo method for identification of skin sensitising chemicals and as such is potentially valuable as a benchmark for assessment of non-animal approaches. However, in common with all predictive test methods, the LLNA is subject to false positives and false negatives with an overall level of accuracy said variously to be approximately 80% or 90%. It is also necessary to consider the extent to which, for true positives, LLNA potency correlates with human potency. In this paper LLNA potency and human potency are compared so as to express quantitatively the correlation between them, and reasons for non-agreement between LLNA and human potency are analysed. This leads to a better definition of the applicability domain of the LLNA, within which LLNA data can be used confidently to predict human potency and as a benchmark to assess the performance of non-animal approaches. Copyright © 2018. Published by Elsevier Inc.

Gravimetric method for in vitro calibration of skin hydration measurements.

PubMed

Martinsen, Ørjan G; Grimnes, Sverre; Nilsen, Jon K; Tronstad, Christian; Jang, Wooyoung; Kim, Hongsig; Shin, Kunsoo; Naderi, Majid; Thielmann, Frank

2008-02-01

A novel method for in vitro calibration of skin hydration measurements is presented. The method combines gravimetric and electrical measurements and reveals an exponential dependency of measured electrical susceptance to absolute water content in the epidermal stratum corneum. The results also show that absorption of water into the stratum corneum exhibits three different phases with significant differences in absorption time constant. These phases probably correspond to bound, loosely bound, and bulk water.

Correlates and responsiveness to change of measures of skin and musculoskeletal disease in early diffuse systemic sclerosis.

PubMed

Wiese, Alexandra B; Berrocal, Veronica J; Furst, Daniel E; Seibold, James R; Merkel, Peter A; Mayes, Maureen D; Khanna, Dinesh

2014-11-01

Skin and musculoskeletal involvement are frequently present early in diffuse cutaneous systemic sclerosis (dcSSc). The current study examined the correlates for skin and musculoskeletal measures in a 1-year longitudinal observational study. Patients with dcSSc were recruited at 4 US centers and enrolled in a 1-year study. Prespecified and standardized measures included physician and patient assessments of skin involvement, modified Rodnan skin score (MRSS), durometer score, Health Assessment Questionnaire disability index, serum creatine phosphokinase, tender joint counts, and presence/absence of tendon friction rubs, small joint contractures, and large joint contractures. Additionally, physician and patient global health assessments and health-related quality of life assessments were recorded. Correlations were computed among the baseline global assessments, skin variables, and musculoskeletal variables. Using the followup physician and patient anchors, effect sizes were calculated. A total of 200 patients were studied: 75% were women, mean ± SD age was 50.0 ± 11.9 years, and mean ± SD disease duration from first non-Raynaud's phenomenon symptom was 1.6 ± 1.4 years. Physician global health assessment had large correlations with MRSS (r = 0.60) and physician-reported skin involvement visual analog scale in the last month (r = 0.74), whereas patient global assessment had large correlations with MRSS, the Short Form 36 health survey physical component scale, skin interference, and skin involvement in the last month (r = 0.37-0.72). Four of 9 skin variables had moderate to large effect sizes (0.51-1.09). Physician and patient global assessments have larger correlations with skin measures compared to musculoskeletal measures. From a clinical trial perspective, skin variables were more responsive to change than musculoskeletal variables over a 1-year period, although both provide complementary information. Copyright © 2014 by the American College of Rheumatology.

Correlates and Responsiveness to Change of Measures of Skin and Musculoskeletal Disease in Early Diffuse Systemic Sclerosis

PubMed Central

Wiese, Alexandra B.; Berrocal, Veronica J.; Furst, Daniel E.; Seibold, James R.; Merkel, Peter A.; Mayes, Maureen D.; Khanna, Dinesh

2015-01-01

Objective Skin and musculoskeletal involvement are frequently present early in diffuse cutaneous systemic sclerosis (dcSSc). The current study examined the correlates for skin and musculoskeletal measures in a 1-year longitudinal observational study. Methods Patients with dcSSc were recruited at 4 US centers and enrolled in a 1-year study. Prespecified and standardized measures included physician and patient assessments of skin involvement, modified Rodnan skin score (MRSS), durometer score, Health Assessment Questionnaire disability index, serum creatine phosphokinase, tender joint counts, and presence/absence of tendon friction rubs, small joint contractures, and large joint contractures. Additionally, physician and patient global health assessments and health-related quality of life assessments were recorded. Correlations were computed among the baseline global assessments, skin variables, and musculoskeletal variables. Using the followup physician and patient anchors, effect sizes were calculated. Results A total of 200 patients were studied: 75% were women, mean ± SD age was 50.0 ± 11.9 years, and mean ± SD disease duration from first non–Raynaud’s phenomenon symptom was 1.6 ± 1.4 years. Physician global health assessment had large correlations with MRSS (r = 0.60) and physician-reported skin involvement visual analog scale in the last month (r = 0.74), whereas patient global assessment had large correlations with MRSS, the Short Form 36 health survey physical component scale, skin interference, and skin involvement in the last month (r = 0.37–0.72). Four of 9 skin variables had moderate to large effect sizes (0.51–1.09). Conclusion Physician and patient global assessments have larger correlations with skin measures compared to musculoskeletal measures. From a clinical trial perspective, skin variables were more responsive to change than musculoskeletal variables over a 1-year period, although both provide complementary information. PMID:24692361

Smartphone-based multispectral imaging: system development and potential for mobile skin diagnosis

PubMed Central

Kim, Sewoong; Cho, Dongrae; Kim, Jihun; Kim, Manjae; Youn, Sangyeon; Jang, Jae Eun; Je, Minkyu; Lee, Dong Hun; Lee, Boreom; Farkas, Daniel L.; Hwang, Jae Youn

2016-01-01

We investigate the potential of mobile smartphone-based multispectral imaging for the quantitative diagnosis and management of skin lesions. Recently, various mobile devices such as a smartphone have emerged as healthcare tools. They have been applied for the early diagnosis of nonmalignant and malignant skin diseases. Particularly, when they are combined with an advanced optical imaging technique such as multispectral imaging and analysis, it would be beneficial for the early diagnosis of such skin diseases and for further quantitative prognosis monitoring after treatment at home. Thus, we demonstrate here the development of a smartphone-based multispectral imaging system with high portability and its potential for mobile skin diagnosis. The results suggest that smartphone-based multispectral imaging and analysis has great potential as a healthcare tool for quantitative mobile skin diagnosis. PMID:28018743

Smartphone-based multispectral imaging: system development and potential for mobile skin diagnosis.

PubMed

Kim, Sewoong; Cho, Dongrae; Kim, Jihun; Kim, Manjae; Youn, Sangyeon; Jang, Jae Eun; Je, Minkyu; Lee, Dong Hun; Lee, Boreom; Farkas, Daniel L; Hwang, Jae Youn

2016-12-01

We investigate the potential of mobile smartphone-based multispectral imaging for the quantitative diagnosis and management of skin lesions. Recently, various mobile devices such as a smartphone have emerged as healthcare tools. They have been applied for the early diagnosis of nonmalignant and malignant skin diseases. Particularly, when they are combined with an advanced optical imaging technique such as multispectral imaging and analysis, it would be beneficial for the early diagnosis of such skin diseases and for further quantitative prognosis monitoring after treatment at home. Thus, we demonstrate here the development of a smartphone-based multispectral imaging system with high portability and its potential for mobile skin diagnosis. The results suggest that smartphone-based multispectral imaging and analysis has great potential as a healthcare tool for quantitative mobile skin diagnosis.

[Development of a system for static measurement of skin-muscle hardness and a fundamental study on its applications].

PubMed

Honda, T

1990-10-01

There have been many attempts to quantitatively measure the hardness of skin-muscle, but no objective method for doing so has been established, because there is no universal standard for the hardness of organisms. The author considered elasticity and viscosity as the most important mechanical properties of the hardness of skin-muscle and applied the Maxwell model, in which a spring and a dash-pot are arranged in a series, to the static mechanical behavior of skin-muscle. A relatively large globular pressing body with a radius of 5 mm was set as a transducer in the measuring system, so that the conformity of the practically measured values to those calculated theoretically by the model was increased. Strain of skin-muscle is expressed as a function of the load, which includes indices of elasticity (1/M) (M(N/mm2) = E/(1-lambda 2) (E: Young's modulus, lambda:Poisson's ratio)) and viscosity (1/eta) (eta:modulus of viscosity) in a particular region. Because hardness is defined as the degree of resistance against transformation by loading, decreases in the indices of both elasticity and viscosity mean increases of hardness. With 150 male and female office workers chosen as the subjects, the model was examined and the indices were calculated. The results were as follows. 1) Very good conformity of practically measured values to those calculated theoretically by the Maxwell model was recognized within the range of load velocity from 0.3 G to 3.0 G (N/sec). 2) In both males and females the regions with values nearest to those of a Newtonian fluid were, in descending order, the distal phalanxes of digiti 2-4, the palm, the distal phalanx of the first digitus and the arm. In reverse order these regions approached complete elasticity. 3) In males it was suggested that the element of viscosity in the region of the biceps brachii muscle and the hardness in the regions of the brachioradialis, the flexor carpi radialis and palmalis longus muscles and the distal phalanxes of the 4

Soft, skin-mounted microfluidic systems for measuring secretory fluidic pressures generated at the surface of the skin by eccrine sweat glands.

PubMed

Choi, Jungil; Xue, Yeguang; Xia, Wei; Ray, Tyler R; Reeder, Jonathan T; Bandodkar, Amay J; Kang, Daeshik; Xu, Shuai; Huang, Yonggang; Rogers, John A

2017-07-25

During periods of activity, sweat glands produce pressures associated with osmotic effects to drive liquid to the surface of the skin. The magnitudes of these pressures may provide insights into physiological health, the intensity of physical exertion, psychological stress factors and/other information of interest, yet they are currently unknown due to absence of means for non-invasive measurement. This paper introduces a thin, soft wearable microfluidic system that mounts onto the surface of the skin to enable precise and routine measurements of secretory fluidic pressures generated at the surface of the skin by eccrine sweat glands (surface SPSG, or s-SPSG) at nearly any location on the body. These platforms incorporate an arrayed collection of unit cells each of which includes an opening to the skin, an inlet through which sweat can flow, a capillary bursting valve (CBV) with a unique bursting pressure (BP), a corresponding microreservoir to receive sweat and an outlet to the surrounding ambient to allow release of backpressure. The BPs systematically span the physiologically relevant range, to enable a measurement precision approximately defined by the ratio of the range to the number of unit cells. Human studies demonstrate measurements of s-SPSG under different conditions, from various regions of the body. Average values in healthy young adults lie between 2.4 and 2.9 kPa. Sweat associated with vigorous exercise have s-SPSGs that are somewhat higher than those associated with sedentary activity. For all conditions, the forearm and lower back tend to yield the highest and lowest s-SPSGs, respectively.

Laser Interferometer Skin-Friction measurements of crossing-shock wave/turbulent boundary-layer interactions

NASA Technical Reports Server (NTRS)

Garrison, T. J.; Settles, G. S.

1993-01-01

Wall shear stress measurements beneath crossingshock wave/turbulent boundary-layer interactions have been made for three interactions of different strengths. The interactions are generated by two sharp fins at symmetric angles of attack mounted on a flat plate. The shear stress measurements were made for fin angles of 7 and 11 degrees at Mach 3 and 15 degrees at Mach 4. The measurements were made using a Laser Interferometer Skin Friction (LISF) meter; a device which determines the wail shear by optically measuring the time rate of thinning of an oil film placed on the test model surface. Results of the measurements reveal high skin friction coefficients in the vicinity of the fin/plate junction and the presence of quasi-two-dimensional flow separation on the interaction centerline. Additionally, two Navier-Stokes computations, one using a Baldwin-Lomax turbulence model and one using a k- model, are compared to the experimental results for the Mach 4, 15 degree interaction case. While the k- model did a reasonable job of predicting the overall trend in portions of the skin friction distribution, neither computation fully captured the physics of the near surface flow in this complex interaction.

Modelling the effect of mixture components on permeation through skin.

PubMed

Ghafourian, T; Samaras, E G; Brooks, J D; Riviere, J E

2010-10-15

A vehicle influences the concentration of penetrant within the membrane, affecting its diffusivity in the skin and rate of transport. Despite the huge amount of effort made for the understanding and modelling of the skin absorption of chemicals, a reliable estimation of the skin penetration potential from formulations remains a challenging objective. In this investigation, quantitative structure-activity relationship (QSAR) was employed to relate the skin permeation of compounds to the chemical properties of the mixture ingredients and the molecular structures of the penetrants. The skin permeability dataset consisted of permeability coefficients of 12 different penetrants each blended in 24 different solvent mixtures measured from finite-dose diffusion cell studies using porcine skin. Stepwise regression analysis resulted in a QSAR employing two penetrant descriptors and one solvent property. The penetrant descriptors were octanol/water partition coefficient, logP and the ninth order path molecular connectivity index, and the solvent property was the difference between boiling and melting points. The negative relationship between skin permeability coefficient and logP was attributed to the fact that most of the drugs in this particular dataset are extremely lipophilic in comparison with the compounds in the common skin permeability datasets used in QSAR. The findings show that compounds formulated in vehicles with small boiling and melting point gaps will be expected to have higher permeation through skin. The QSAR was validated internally, using a leave-many-out procedure, giving a mean absolute error of 0.396. The chemical space of the dataset was compared with that of the known skin permeability datasets and gaps were identified for future skin permeability measurements. Copyright 2010 Elsevier B.V. All rights reserved.

Quantitative force measurements using frequency modulation atomic force microscopy—theoretical foundations

NASA Astrophysics Data System (ADS)

Sader, John E.; Uchihashi, Takayuki; Higgins, Michael J.; Farrell, Alan; Nakayama, Yoshikazu; Jarvis, Suzanne P.

2005-03-01

Use of the atomic force microscope (AFM) in quantitative force measurements inherently requires a theoretical framework enabling conversion of the observed deflection properties of the cantilever to an interaction force. In this paper, the theoretical foundations of using frequency modulation atomic force microscopy (FM-AFM) in quantitative force measurements are examined and rigorously elucidated, with consideration being given to both 'conservative' and 'dissipative' interactions. This includes a detailed discussion of the underlying assumptions involved in such quantitative force measurements, the presentation of globally valid explicit formulae for evaluation of so-called 'conservative' and 'dissipative' forces, discussion of the origin of these forces, and analysis of the applicability of FM-AFM to quantitative force measurements in liquid.

Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models

PubMed Central

Brendtke, Rico; Wiehl, Michael; Groeber, Florian; Schwarz, Thomas; Walles, Heike; Hansmann, Jan

2016-01-01

Tissue dehydration results in three major types of exsiccosis—hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring. PMID:27046226

Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models.

PubMed

Brendtke, Rico; Wiehl, Michael; Groeber, Florian; Schwarz, Thomas; Walles, Heike; Hansmann, Jan

2016-01-01

Tissue dehydration results in three major types of exsiccosis--hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring.

Systematic study of error sources in supersonic skin-friction balance measurements

NASA Technical Reports Server (NTRS)

Allen, J. M.

1976-01-01

An experimental study was performed to investigate potential error sources in data obtained with a self-nulling, moment-measuring, skin-friction balance. The balance was installed in the sidewall of a supersonic wind tunnel, and independent measurements of the three forces contributing to the balance output (skin friction, lip force, and off-center normal force) were made for a range of gap size and element protrusion. The relatively good agreement between the balance data and the sum of these three independently measured forces validated the three-term model used. No advantage to a small gap size was found; in fact, the larger gaps were preferable. Perfect element alignment with the surrounding test surface resulted in very small balance errors. However, if small protrusion errors are unavoidable, no advantage was found in having the element slightly below the surrounding test surface rather than above it.

A nonintrusive laser interferometer method for measurement of skin friction

NASA Technical Reports Server (NTRS)

Monson, D. J.

1983-01-01

A method is described for monitoring the changing thickness of a thin oil film subject to an aerodynamic shear stress using two focused laser beams. The measurement is then simply analyzed in terms of the surface skin friction of the flow. The analysis includes the effects of arbitrarily large pressure and skin friction gradients, gravity, and time varying oil temperature. It may also be applied to three dimensional flows with unknown direction. Applications are presented for a variety of flows, including two dimensional flows, three dimensional swirling flows, separated flow, supersonic high Reynolds number flows, and delta wing vortical flows. Previously announced in STAR as N83-12393

Quantitative wound healing measurement and monitoring system based on an innovative 3D imaging system

NASA Astrophysics Data System (ADS)

Yi, Steven; Yang, Arthur; Yin, Gongjie; Wen, James

2011-03-01

In this paper, we report a novel three-dimensional (3D) wound imaging system (hardware and software) under development at Technest Inc. System design is aimed to perform accurate 3D measurement and modeling of a wound and track its healing status over time. Accurate measurement and tracking of wound healing enables physicians to assess, document, improve, and individualize the treatment plan given to each wound patient. In current wound care practices, physicians often visually inspect or roughly measure the wound to evaluate the healing status. This is not an optimal practice since human vision lacks precision and consistency. In addition, quantifying slow or subtle changes through perception is very difficult. As a result, an instrument that quantifies both skin color and geometric shape variations would be particularly useful in helping clinicians to assess healing status and judge the effect of hyperemia, hematoma, local inflammation, secondary infection, and tissue necrosis. Once fully developed, our 3D imaging system will have several unique advantages over traditional methods for monitoring wound care: (a) Non-contact measurement; (b) Fast and easy to use; (c) up to 50 micron measurement accuracy; (d) 2D/3D Quantitative measurements;(e) A handheld device; and (f) Reasonable cost (< $1,000).

Methodology for diagnosing of skin cancer on images of dermatologic spots by spectral analysis

PubMed Central

Guerra-Rosas, Esperanza; Álvarez-Borrego, Josué

2015-01-01

In this paper a new methodology for the diagnosing of skin cancer on images of dermatologic spots using image processing is presented. Currently skin cancer is one of the most frequent diseases in humans. This methodology is based on Fourier spectral analysis by using filters such as the classic, inverse and k-law nonlinear. The sample images were obtained by a medical specialist and a new spectral technique is developed to obtain a quantitative measurement of the complex pattern found in cancerous skin spots. Finally a spectral index is calculated to obtain a range of spectral indices defined for skin cancer. Our results show a confidence level of 95.4%. PMID:26504638

Optical diffuse reflectance accessory for measurements of skin tissue by near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Marbach, R.; Heise, H. M.

1995-02-01

An optimized accessory for measuring the diffuse reflectance spectra of human skin tissue in the near-infrared spectral range is presented. The device includes an on-axis ellipsoidal collecting mirror with efficient illumination optics for small sampling areas of bulky body specimens. The optical design is supported by the results of a Monte Carlo simulation study of the reflectance characteristics of skin tissue. Because the results evolved from efforts to measure blood glucose noninvasively, the main emphasis is placed on the long-wavelength near-infrared range where sufficient penetration depth for radiation into tissue is still available. The accessory is applied for in vivo diffuse reflectance measurements.

Stress Evaluation while Prolonged Driving Operation Using the Facial Skin Temperature

NASA Astrophysics Data System (ADS)

Asano, Hirotoshi; Muto, Takumi; Ide, Hideto

There is a relation to the accident of a car and the physiological and psychological state of a driver. The stress may lead to the fall of a fatigue or attentiveness. Therefore, it is an important subject from viewpoint such as accident prevention to evaluate the mental state of a driver. The study aimed at the development of a quantitative instrumentation technology of the stress when a subject is driving for a long time. First of all, we measured the physiological and psychological stress of a driver. The facial skin temperature and ventricular rate that was driver's physiological amount were measured and compared it with visual analog scale of the subjective amount. It was able to be obtaining of the high correlation in facial skin temperature and visual analog scale from the outcome of the experiment. Therefore, the possibility of appreciable of driver's stress at a facial skin temperature was shown. As a result of the experiment, we showed a possibility that facial skin temperature could evaluate long driving stress.

Skin friction measurement in complex flows using thin oil film techniques

NASA Technical Reports Server (NTRS)

1994-01-01

The NASA Grant NAG2-261 was initiated to support a program of research to study complex flows that occur in flight and laboratory experiments by building, testing and optimizing an on-board technique for direct measurement of surface shear stress using thin oil film techniques. The program of research has proceeded under the supervision of the NASA Ames Research Center and with further cooperation from the NASA Ames-Dryden and NASA Langley Research Centers. In accordance with the original statement of work, the following research milestones were accomplished: (1) design and testing of an internally mounted one-directional skin friction meter to demonstrate the feasibility of the concept; (2) design and construction of a compact instrument capable of measuring skin friction in two directions; (3) study of transitional and fully turbulent boundary layers over a flat plate with and without longitudinal pressure gradients utilizing the compact two-directional skin friction meter; (4) study of the interaction between a turbulent boundary layer and a shock wave generated by a compression corner using the two-directional meter; and (5) flight qualification of the compact meter and accompanying electronic and pneumatic systems, preliminary installation into flight test fixture.

The use of optical coherence tomography to analyze the efficacy of skin care products

NASA Astrophysics Data System (ADS)

Irani, Sarosh; Turani, Zahra; Fotouhi, Audrey; Daveluy, Steven; Mehregan, Darius; Chen, Wei; Gelovani, Juri; Nasiriavanaki, Mohammadreza

2018-02-01

In this study, we assess the applicability of optical coherence tomography (OCT) for non-invasive imaging of skin morphology for the assessment of efficacy of cosmetic skin wrinkle-reduction products in humans. Evaluation of skin care products for reduction of facial wrinkles is largely limited to photographic (non-quantitative) comparison of skin surface texture before and after either single or prolonged application of skin care product. OCT could be a technique for monitoring changes in cross-sectional skin morphology. An optical attenuation coefficient analysis is also carried out to quantitatively study the changes in different layers of the skin.

Smile line assessment comparing quantitative measurement and visual estimation.

PubMed

Van der Geld, Pieter; Oosterveld, Paul; Schols, Jan; Kuijpers-Jagtman, Anne Marie

2011-02-01

Esthetic analysis of dynamic functions such as spontaneous smiling is feasible by using digital videography and computer measurement for lip line height and tooth display. Because quantitative measurements are time-consuming, digital videography and semiquantitative (visual) estimation according to a standard categorization are more practical for regular diagnostics. Our objective in this study was to compare 2 semiquantitative methods with quantitative measurements for reliability and agreement. The faces of 122 male participants were individually registered by using digital videography. Spontaneous and posed smiles were captured. On the records, maxillary lip line heights and tooth display were digitally measured on each tooth and also visually estimated according to 3-grade and 4-grade scales. Two raters were involved. An error analysis was performed. Reliability was established with kappa statistics. Interexaminer and intraexaminer reliability values were high, with median kappa values from 0.79 to 0.88. Agreement of the 3-grade scale estimation with quantitative measurement showed higher median kappa values (0.76) than the 4-grade scale estimation (0.66). Differentiating high and gummy smile lines (4-grade scale) resulted in greater inaccuracies. The estimation of a high, average, or low smile line for each tooth showed high reliability close to quantitative measurements. Smile line analysis can be performed reliably with a 3-grade scale (visual) semiquantitative estimation. For a more comprehensive diagnosis, additional measuring is proposed, especially in patients with disproportional gingival display. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Skin hydration, microrelief and greasiness of normal skin in Antarctica.

PubMed

Tsankov, N; Mateev, D; Darlenski, R

2018-03-01

The skin is the primary defence of the human body against external factors from physical, chemical, mechanical and biologic origin. Climatic factors together with low temperature and sun radiation affect the skin. The effect of climatic conditions in Antarctica on healthy skin has not been previously addressed. The aim of this study was to evaluate the changes in the skin hydration, greasiness and microrelief due to the extreme climatic environmental factors during the stay of the members of the Bulgarian Antarctic expedition. Fifty-nine Caucasian healthy subjects, 42 men and 17 women with mean age 50.9 years (27-68), were enrolled. The study was performed in five consecutive years from 2011 to 2016 at the Bulgarian Antarctic base camp at Livingston Island. The study protocol consisted of two parts: study A: duration of 15 days with measurement of skin physiology parameters on a daily basis, and study B: five measurements at baseline and at days 14, 30, 45 and 50 upon arrival in Antarctica. We measured three biophysical parameters related to skin physiology at cheek skin by an impedance measuring device. No statistically significant difference between parameters at the different measurement points. There is a variation in skin hydration reaching its lower point at day 11 and then returning to values similar to baseline. Initially, an increase in skin greasiness was witnessed with a sharp depression at day 11 and final values at day 15 resembling the ones at baseline. An increase, although not statistically significant, in skin roughness was observed in the first 15 days of the study. Study B showed no statistically significant variances between values of the three parameters. Our studies show the pioneer results of the effect of Antarctic climate on human skin physiology. © 2017 European Academy of Dermatology and Venereology.

Human age and skin physiology shape diversity and abundance of Archaea on skin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moissl-Eichinger, Christine; Probst, Alexander J.; Birarda, Giovanni

The human skin microbiome acts as an important barrier protecting our body from pathogens and other environmental influences. Recent investigations have provided evidence that Archaea are a constant but highly variable component of the human skin microbiome, yet factors that determine their abundance changes are unknown. Here, we tested the hypothesis that the abundance of archaea on human skin is influenced by human age and skin physiology by quantitative PCR of 51 different skin samples taken from human subjects of various age. Our results reveal that archaea are more abundant in human subjects either older than 60 years or youngermore » than 12 years as compared to middle-aged human subjects. These results, together with results obtained from spectroscopy analysis, allowed us gain first insights into a potential link of lower sebum levels and lipid content and thus reduced skin moisture with an increase in archaeal signatures. In conclusion, amplicon sequencing of selected samples revealed the prevalence of specific eury- and mainly thaumarchaeal taxa, represented by a core archaeome of the human skin.« less

Human age and skin physiology shape diversity and abundance of Archaea on skin

DOE PAGES

Moissl-Eichinger, Christine; Probst, Alexander J.; Birarda, Giovanni; ...

2017-06-22

The human skin microbiome acts as an important barrier protecting our body from pathogens and other environmental influences. Recent investigations have provided evidence that Archaea are a constant but highly variable component of the human skin microbiome, yet factors that determine their abundance changes are unknown. Here, we tested the hypothesis that the abundance of archaea on human skin is influenced by human age and skin physiology by quantitative PCR of 51 different skin samples taken from human subjects of various age. Our results reveal that archaea are more abundant in human subjects either older than 60 years or youngermore » than 12 years as compared to middle-aged human subjects. These results, together with results obtained from spectroscopy analysis, allowed us gain first insights into a potential link of lower sebum levels and lipid content and thus reduced skin moisture with an increase in archaeal signatures. In conclusion, amplicon sequencing of selected samples revealed the prevalence of specific eury- and mainly thaumarchaeal taxa, represented by a core archaeome of the human skin.« less

Mapping tissue shear modulus on Thiel soft-embalmed mouse skin with shear wave optical coherence elastography

NASA Astrophysics Data System (ADS)

Song, Shaozhen; Joy, Joyce; Wang, Ruikang K.; Huang, Zhihong

2015-03-01

A quantitative measurement of the mechanical properties of biological tissue is a useful assessment of its physiologic conditions, which may aid medical diagnosis and treatment of, e.g., scleroderma and skin cancer. Traditional elastography techniques such as magnetic resonance elastography and ultrasound elastography have limited scope of application on skin due to insufficient spatial resolution. Recently, dynamic / transient elastography are attracting more applications with the advantage of non-destructive measurements, and revealing the absolute moduli values of tissue mechanical properties. Shear wave optical coherence elastography (SW-OCE) is a novel transient elastography method, which lays emphasis on the propagation of dynamic mechanical waves. In this study, high speed shear wave imaging technique was applied to a range of soft-embalmed mouse skin, where 3 kHz shear waves were launched with a piezoelectric actuator as an external excitation. The shear wave velocity was estimated from the shear wave images, and used to recover a shear modulus map in the same OCT imaging range. Results revealed significant difference in shear modulus and structure in compliance with gender, and images on fresh mouse skin are also compared. Thiel embalming technique is also proven to present the ability to furthest preserve the mechanical property of biological tissue. The experiment results suggest that SW-OCE is an effective technique for quantitative estimation of skin tissue biomechanical status.

Evaluation of airway protection: Quantitative timing measures versus penetration/aspiration score.

PubMed

Kendall, Katherine A

2017-10-01

Quantitative measures of swallowing function may improve the reliability and accuracy of modified barium swallow (MBS) study interpretation. Quantitative study analysis has not been widely instituted, however, secondary to concerns about the time required to make measures and a lack of research demonstrating impact on MBS interpretation. This study compares the accuracy of the penetration/aspiration (PEN/ASP) scale (an observational visual-perceptual assessment tool) to quantitative measures of airway closure timing relative to the arrival of the bolus at the upper esophageal sphincter in identifying a failure of airway protection during deglutition. Retrospective review of clinical swallowing data from a university-based outpatient clinic. Swallowing data from 426 patients were reviewed. Patients with normal PEN/ASP scores were identified, and the results of quantitative airway closure timing measures for three liquid bolus sizes were evaluated. The incidence of significant airway closure delay with and without a normal PEN/ASP score was determined. Inter-rater reliability for the quantitative measures was calculated. In patients with a normal PEN/ASP score, 33% demonstrated a delay in airway closure on at least one swallow during the MBS study. There was no correlation between PEN/ASP score and airway closure delay. Inter-rater reliability for the quantitative measure of airway closure timing was nearly perfect (intraclass correlation coefficient = 0.973). The use of quantitative measures of swallowing function, in conjunction with traditional visual perceptual methods of MBS study interpretation, improves the identification of airway closure delay, and hence, potential aspiration risk, even when no penetration or aspiration is apparent on the MBS study. 4. Laryngoscope, 127:2314-2318, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Quantitative endoscopy: initial accuracy measurements.

PubMed

Truitt, T O; Adelman, R A; Kelly, D H; Willging, J P

2000-02-01

The geometric optics of an endoscope can be used to determine the absolute size of an object in an endoscopic field without knowing the actual distance from the object. This study explores the accuracy of a technique that estimates absolute object size from endoscopic images. Quantitative endoscopy involves calibrating a rigid endoscope to produce size estimates from 2 images taken with a known traveled distance between the images. The heights of 12 samples, ranging in size from 0.78 to 11.80 mm, were estimated with this calibrated endoscope. Backup distances of 5 mm and 10 mm were used for comparison. The mean percent error for all estimated measurements when compared with the actual object sizes was 1.12%. The mean errors for 5-mm and 10-mm backup distances were 0.76% and 1.65%, respectively. The mean errors for objects <2 mm and > or =2 mm were 0.94% and 1.18%, respectively. Quantitative endoscopy estimates endoscopic image size to within 5% of the actual object size. This method remains promising for quantitatively evaluating object size from endoscopic images. It does not require knowledge of the absolute distance of the endoscope from the object, rather, only the distance traveled by the endoscope between images.

The local lymph node assay and skin sensitization testing.

PubMed

Kimber, Ian; Dearman, Rebecca J

2010-01-01

The mouse local lymph node assay (LLNA) is a method for the identification and characterization of skin sensitization hazards. In this context the method can be used both to identify contact allergens, and also determine the relative skin sensitizing potency as a basis for derivation of effective risk assessments.The assay is based on measurement of proliferative responses by draining lymph node cells induced following topical exposure of mice to test chemicals. Such responses are known to be causally and quantitatively associated with the acquisition of skin sensitization and therefore provide a relevant marker for characterization of contact allergic potential.The LLNA has been the subject of exhaustive evaluation and validation exercises and has been assigned Organization for Economic Cooperation and Development (OECD) test guideline 429. Herein we describe the conduct and interpretation of the LLNA.

Indium adhesion provides quantitative measure of surface cleanliness

NASA Technical Reports Server (NTRS)

Krieger, G. L.; Wilson, G. J.

1968-01-01

Indium tipped probe measures hydrophobic and hydrophilic contaminants on rough and smooth surfaces. The force needed to pull the indium tip, which adheres to a clean surface, away from the surface provides a quantitative measure of cleanliness.

Laser interferometer skin-friction measurements of crossing-shock-wave/turbulent-boundary-layer interactions

NASA Technical Reports Server (NTRS)

Garrison, T. J.; Settles, G. S.; Narayanswami, N.; Knight, D. D.

1994-01-01

Wall shear stress measurements beneath crossing-shock-wave/turbulent boundary-layer interactions have been made for three interactions of different strengths. The interactions are generated by two sharp fins at symetric angles of attack mounted on a flat plate. The shear stress measurements were made for fin angles of 7 and 11 deg at Mach 3 and 15 deg at Mach 3.85. The measurements were made using a laser interferometer skin-friction meter, a device that determines the wall shear by optically measuring the time rate of thinning of an oil film placed on the test model surface. Results of the measurements reveal high skin-friction coefficients in the vicinity of the fin/plate junction and the presence of quasi-two-dimensional flow separation on the interaction center line. Additionally, two Navier-Stokes computations, one using a Baldwin-Lomax turbulence model and one using a k-epsilon model, are compared with the experimental results for the Mach 3.85, 15-deg interaction case. Although the k-epsilon model did a reasonable job of predicting the overall trend in portions of the skin-friction distribution, neither computation fully captured the physics of the near-surface flow in this complex interaction.

Quantitative dermal measurements following treatment with AirGent.

PubMed

Kobus, Kazimierz F; Dydymski, Tomasz

2010-09-01

As an alternative to other minimally-invasive approaches to facial rejuvenation, enhancement and treatment of the dermis with a compressed air molecule of hyaluronic acid (HA) is a promising method in that it lacks some of the drawbacks of other procedures. The novelty of these systems, one of which is tested in this study, is based on the supposition that jet lateral dispersion of HA produces both instant dermal augmentation and specific wound-healing processes, leading to its long-term dermal thickening. The authors report on the efficacy and safety of the AirGent system (PerfAction, Rehovot, Israel), which is a renewal system designed to initiate a wound-healing process in the dermal layer. It is a computer-guided system that delivers treatment through compressed air molecules of HA to the dermal layer of the skin. The authors treated 20 patients (a total of 105 treatment sessions) with the AirGent system between May 2008 and November 2008. Each patient received three treatments at three- to four-week intervals. Each patient's skin thickness was measured with ultrasonography pretreatment, immediately after each session, and at six months posttreatment. Seven days after the last procedure, an increase in skin thickness was observed in all patients. The most significant differences were noted in the upper lip area, where the thickness had increased by an average of 1.3 mm. Six months after the last session, an increase in skin thickness was still noted in most patients, at which time the biggest difference was noted around the eyes, where the skin remained thicker by an average of 0.77 mm over baseline. According to the results of the Global Improvement Assessment questionnaire, at the six-month follow-up to evaluate their satisfaction with the long-term results, at least 59.9% of patients still noted at least a slight improvement in their appearance. Although a small group of patients and a relatively short period of observation limit the scope of our conclusions

Is skin penetration a determining factor in skin sensitization ...

EPA Pesticide Factsheets

Summary:Background. It is widely accepted that substances that cannot penetrate through the skin will not be sensitisers. Thresholds based on relevant physicochemical parameters such as a LogKow > 1 and a MW 1 is a true requirement for sensitisation.Methods. A large dataset of substances that had been evaluated for their skin sensitisation potential, together with measured LogKow values was compiled from the REACH database. The incidence of skin sensitisers relative to non-skin sensitisers below and above the LogKow = 1 threshold was evaluated. Results. 1482 substances with associated skin sensitisation outcomes and measured LogKow values were identified. 305 substances had a measured LogKow < 0 and of those, 38 were sensitisers.Conclusions. There was no significant difference in the incidence of skin sensitisation above and below the LogKow = 1 threshold. Reaction chemistry considerations could explain the skin sensitisation observed for the 38 sensitisers with a LogKow < 0. The LogKow threshold is a self-evident truth borne out from the widespread misconception that the ability to efficiently penetrate the stratum corneum is a key determinant of skin sensitisation potential and potency. Using the REACH data extracted to test out the validity of common assumptions in the skin sensitization AOP. Builds on trying to develop a proof of concept IATA

Skin color and makeup strategies of women from different ethnic groups.

PubMed

Caisey, L; Grangeat, F; Lemasson, A; Talabot, J; Voirin, A

2006-12-01

The development of a world-wide makeup foundation range requires a thorough understanding of skin color features of women around the world. To understand the cosmetic needs of women from different ethnic groups, we measured skin color in five different groups (French and American Caucasian, Japanese, African-American, and Hispanic-American) and compared the data obtained with women's self-perception of skin color, before or after applying their usual foundation product. Skin color was measured using a spectro-radiometer and a spheric lighting device with CCD camera ensuring a highly reliable imaging and data acquisition. The diversity of skin types involved in the study lead to define a large, continuous color space where color spectra from various ethnic groups overlap. Three types of complexion - dark, medium, or light - were distinguished in each group. Only Japanese women did not identify with this lightness scale and considered it makes more sense to classify their skin according to a pink-ocher-beige color scale. The approach however revealed the great variety of skin colors within each ethnic group and the extent of unevenness. A fairly good agreement appeared between women's self-perception and data from color measurements but in Hispanic-American group. Data recorded, after foundation was applied, showed overall consistency with makeup strategy as described by volunteers except for the latter group whose approach looked more uncertain and variable. The findings of the study demonstrate the advantage of combining qualitative and quantitative approach for assessing the cosmetic needs and expectations of women from different ethnic origin and cultural background.

Skin color measurement in Chinese female population: analysis of 407 cases from 4 major cities of China.

PubMed

Wei, Liu; Xuemin, Wang; Wei, Lai; Li, Li; Ping, Zhang; Yanyu, Wu; Ying, Lu; Yan, Li; Yan, Tian; Yan, Wu; Li, Chen

2007-08-01

Color assessment of human skin is an important index both in dermatology and in cosmetology. Skin color measured in 407 Chinese women selected from four different cities in China is reported in the 1976 Commission International de L'eclairage (CIE)-color space, according to the skin color typing method proposed by Chardon et al. in 1991. The skin color of buttocks and hands, which represent sun unexposed and exposed sites, respectively, were measured with a Minolta 2500d chromameter. Individual typology angle (ITA degrees) of each volunteer was calculated based on the measured L* and b* values and her skin complexion was graded accordingly. The results show that most of the volunteers had a "light" skin color at their unexposed sites, namely grade II (65.5%), and then grade III (intermediate, 23.1%), and I (very light, 9.6%). The skin colors at exposed sites of the studied group were mainly grade III (intermediate, 45.7%), followed by grade IV (tan, 42.0%) and II (light, 7.9%). The difference among the investigated cities, the relationship between skin color and ages, and the complexion changes from unexposed site to exposed site were analyzed based on the data from the research. The authors believed that the present results might basically represent the complexion conditions of Chinese women.

Analyses of volatile organic compounds from human skin

PubMed Central

Gallagher, M.; Wysocki, C.J.; Leyden, J.J.; Spielman, A.I.; Sun, X.; Preti, G.

2008-01-01

Summary Background Human skin emits a variety of volatile metabolites, many of them odorous. Much previous work has focused upon chemical structure and biogenesis of metabolites produced in the axillae (underarms), which are a primary source of human body odour. Nonaxillary skin also harbours volatile metabolites, possibly with different biological origins than axillary odorants. Objectives To take inventory of the volatile organic compounds (VOCs) from the upper back and forearm skin, and assess their relative quantitative variation across 25 healthy subjects. Methods Two complementary sampling techniques were used to obtain comprehensive VOC profiles, viz., solid-phase micro extraction and solvent extraction. Analyses were performed using both gas chromatography/mass spectrometry and gas chromatography with flame photometric detection. Results Nearly 100 compounds were identified, some of which varied with age. The VOC profiles of the upper back and forearm within a subject were, for the most part, similar, although there were notable differences. Conclusions The natural variation in nonaxillary skin odorants described in this study provides a baseline of compounds we have identified from both endogenous and exogenous sources. Although complex, the profiles of volatile constituents suggest that the two body locations share a considerable number of compounds, but both quantitative and qualitative differences are present. In addition, quantitative changes due to ageing are also present. These data may provide future investigators of skin VOCs with a baseline against which any abnormalities can be viewed in searching for biomarkers of skin diseases. PMID:18637798

4D-Fingerprint Categorical QSAR Models for Skin Sensitization Based on Classification Local Lymph Node Assay Measures

PubMed Central

Li, Yi; Tseng, Yufeng J.; Pan, Dahua; Liu, Jianzhong; Kern, Petra S.; Gerberick, G. Frank; Hopfinger, Anton J.

2008-01-01

Currently, the only validated methods to identify skin sensitization effects are in vivo models, such as the Local Lymph Node Assay (LLNA) and guinea pig studies. There is a tremendous need, in particular due to novel legislation, to develop animal alternatives, eg. Quantitative Structure-Activity Relationship (QSAR) models. Here, QSAR models for skin sensitization using LLNA data have been constructed. The descriptors used to generate these models are derived from the 4D-molecular similarity paradigm and are referred to as universal 4D-fingerprints. A training set of 132 structurally diverse compounds and a test set of 15 structurally diverse compounds were used in this study. The statistical methodologies used to build the models are logistic regression (LR), and partial least square coupled logistic regression (PLS-LR), which prove to be effective tools for studying skin sensitization measures expressed in the two categorical terms of sensitizer and non-sensitizer. QSAR models with low values of the Hosmer-Lemeshow goodness-of-fit statistic, χHL2, are significant and predictive. For the training set, the cross-validated prediction accuracy of the logistic regression models ranges from 77.3% to 78.0%, while that of PLS-logistic regression models ranges from 87.1% to 89.4%. For the test set, the prediction accuracy of logistic regression models ranges from 80.0%-86.7%, while that of PLS-logistic regression models ranges from 73.3%-80.0%. The QSAR models are made up of 4D-fingerprints related to aromatic atoms, hydrogen bond acceptors and negatively partially charged atoms. PMID:17226934

Quantitative tomographic measurements of opaque multiphase flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

GEORGE,DARIN L.; TORCZYNSKI,JOHN R.; SHOLLENBERGER,KIM ANN

2000-03-01

An electrical-impedance tomography (EIT) system has been developed for quantitative measurements of radial phase distribution profiles in two-phase and three-phase vertical column flows. The EIT system is described along with the computer algorithm used for reconstructing phase volume fraction profiles. EIT measurements were validated by comparison with a gamma-densitometry tomography (GDT) system. The EIT system was used to accurately measure average solid volume fractions up to 0.05 in solid-liquid flows, and radial gas volume fraction profiles in gas-liquid flows with gas volume fractions up to 0.15. In both flows, average phase volume fractions and radial volume fraction profiles from GDTmore » and EIT were in good agreement. A minor modification to the formula used to relate conductivity data to phase volume fractions was found to improve agreement between the methods. GDT and EIT were then applied together to simultaneously measure the solid, liquid, and gas radial distributions within several vertical three-phase flows. For average solid volume fractions up to 0.30, the gas distribution for each gas flow rate was approximately independent of the amount of solids in the column. Measurements made with this EIT system demonstrate that EIT may be used successfully for noninvasive, quantitative measurements of dispersed multiphase flows.« less

Rapid, noninvasive quantitation of skin disease in systemic sclerosis using optical coherence elastography

NASA Astrophysics Data System (ADS)

Du, Yong; Liu, Chih-Hao; Lei, Ling; Singh, Manmohan; Li, Jiasong; Hicks, M. John; Larin, Kirill V.; Mohan, Chandra

2016-04-01

Systemic sclerosis (SSc) is a connective tissue disease that results in excessive accumulation of collagen in the skin and internal organs. Overall, SSc has a rare morbidity (276 cases per million adults in the United States), but has a 10-year survival rate of 55%. Currently, the modified Rodnan skin score (mRSS) is assessed by palpation on 17 sites on the body. However, the mRSS assessed score is subjective and may be influenced by the experience of the rheumatologists. In addition, the inherent elasticity of skin may bias the mRSS assessment in the early stage of SSc, such as oedematous. Optical coherence elastography (OCE) is a rapidly emerging technique, which can assess mechanical contrast in tissues with micrometer spatial resolution. In this work, the OCE technique is applied to assess the mechanical properties of skin in both control and bleomycin (BLM) induced SSc-like disease noninvasively. Young's modulus of the BLM-SSc skin was found be significantly higher than that of normal skin, in both the in vivo and in vitro studies (p<0.05). Thus, OCE is able to differentiate healthy and fibrotic skin using mechanical contrast. It is a promising new technology for quantifying skin involvement in SSc in a rapid, unbiased, and noninvasive manner.

Comparative study on skin dose measurement using MOSFET and TLD for pediatric patients with acute lymphatic leukemia.

PubMed

Al-Mohammed, Huda I; Mahyoub, Fareed H; Moftah, Belal A

2010-07-01

The object of this study was to compare the difference of skin dose measured in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using metal oxide semiconductor field-effect transistors (mobile MOSFET dose verification system (TN-RD-70-W) and thermoluminescent dosimeters (TLD-100 chips, Harshaw/ Bicron, OH, USA). Because TLD has been the most-commonly used technique in the skin dose measurement of TBI, the aim of the present study is to prove the benefit of using the mobile MOSFET (metal oxide semiconductor field effect transistor) dosimeter, for entrance dose measurements during the total body irradiation (TBI) over thermoluminescent dosimeters (TLD). The measurements involved 10 pediatric patients ages between 3 and 14 years. Thermoluminescent dosimeters and MOSFET dosimetry were performed at 9 different anatomic sites on each patient. The present results show there is a variation between skin dose measured with MOSFET and TLD in all patients, and for every anatomic site selected, there is no significant difference in the dose delivered using MOSFET as compared to the prescribed dose. However, there is a significant difference for every anatomic site using TLD compared with either the prescribed dose or MOSFET. The results indicate that the dosimeter measurements using the MOSFET gave precise measurements of prescribed dose. However, TLD measurement showed significant increased skin dose of cGy as compared to either prescribed dose or MOSFET group. MOSFET dosimeters provide superior dose accuracy for skin dose measurement in TBI as compared with TLD.

Human facial skin detection in thermal video to effectively measure electrodermal activity (EDA)

NASA Astrophysics Data System (ADS)

Kaur, Balvinder; Hutchinson, J. Andrew; Leonard, Kevin R.; Nelson, Jill K.

2011-06-01

In the past, autonomic nervous system response has often been determined through measuring Electrodermal Activity (EDA), sometimes referred to as Skin Conductance (SC). Recent work has shown that high resolution thermal cameras can passively and remotely obtain an analog to EDA by assessing the activation of facial eccrine skin pores. This paper investigates a method to distinguish facial skin from non-skin portions on the face to generate a skin-only Dynamic Mask (DM), validates the DM results, and demonstrates DM performance by removing false pore counts. Moreover, this paper shows results from these techniques using data from 20+ subjects across two different experiments. In the first experiment, subjects were presented with primary screening questions for which some had jeopardy. In the second experiment, subjects experienced standard emotion-eliciting stimuli. The results from using this technique will be shown in relation to data and human perception (ground truth). This paper introduces an automatic end-to-end skin detection approach based on texture feature vectors. In doing so, the paper contributes not only a new capability of tracking facial skin in thermal imagery, but also enhances our capability to provide non-contact, remote, passive, and real-time methods for determining autonomic nervous system responses for medical and security applications.

Quantitative comparison of the spreading and invasion of radial growth phase and metastatic melanoma cells in a three-dimensional human skin equivalent model.

PubMed

Haridas, Parvathi; McGovern, Jacqui A; McElwain, Sean D L; Simpson, Matthew J

2017-01-01

tissues. Interestingly, both the WM35 and SK-MEL-28 melanoma cells lead to a breakdown of the basement membrane and eventually enter the dermis. However, these two cell lines invade at different rates, with the SK-MEL-28 melanoma cells invading faster than the WM35 cells. The MSE and HSE models are a reliable platform for studying melanoma invasion in a 3D tissue that is similar to native human skin. Interestingly, we find that the WM35 cell line, that is thought to be associated with radial spreading only, is able to invade into the dermis. The vertical invasion of melanoma cells into the dermal region appears to be associated with a localised disruption of the basement membrane. Presenting our results in terms of time course data, along with images and quantitative measurements of the depth of invasion extends previous 3D work that has often been reported without these details.

Quantitative comparison of the spreading and invasion of radial growth phase and metastatic melanoma cells in a three-dimensional human skin equivalent model

PubMed Central

Haridas, Parvathi; McGovern, Jacqui A.; McElwain, Sean D.L.

2017-01-01

invade deeper into the tissues. Interestingly, both the WM35 and SK-MEL-28 melanoma cells lead to a breakdown of the basement membrane and eventually enter the dermis. However, these two cell lines invade at different rates, with the SK-MEL-28 melanoma cells invading faster than the WM35 cells. Discussion The MSE and HSE models are a reliable platform for studying melanoma invasion in a 3D tissue that is similar to native human skin. Interestingly, we find that the WM35 cell line, that is thought to be associated with radial spreading only, is able to invade into the dermis. The vertical invasion of melanoma cells into the dermal region appears to be associated with a localised disruption of the basement membrane. Presenting our results in terms of time course data, along with images and quantitative measurements of the depth of invasion extends previous 3D work that has often been reported without these details. PMID:28890854

System and Method for Measuring Skin Movement and Strain and Related Techniques

NASA Technical Reports Server (NTRS)

Newman, Dava J. (Inventor); Wessendorf, Ashley M. (Inventor)

2015-01-01

Described herein are systems and techniques for a motion capture system and a three-dimensional (3D) tracking system used to record body position and/or movements/motions and using the data to measure skin strain (a strain field) all along the body while a joint is in motion (dynamic) as well as in a fixed position (static). The data and technique can be used to quantify strains, calculate 3D contours, and derive patterns believed to reveal skin's properties during natural motions.

Advances in Measurement of Skin Friction in Airflow

NASA Technical Reports Server (NTRS)

Brown, James L.; Naughton, Jonathan W.

2006-01-01

The surface interferometric skin-friction (SISF) measurement system is an instrument for determining the distribution of surface shear stress (skin friction) on a wind-tunnel model. The SISF system utilizes the established oil-film interference method, along with advanced image-data-processing techniques and mathematical models that express the relationship between interferograms and skin friction, to determine the distribution of skin friction over an observed region of the surface of a model during a single wind-tunnel test. In the oil-film interference method, a wind-tunnel model is coated with a thin film of oil of known viscosity and is illuminated with quasi-monochromatic, collimated light, typically from a mercury lamp. The light reflected from the outer surface of the oil film interferes with the light reflected from the oil-covered surface of the model. In the present version of the oil-film interference method, a camera captures an image of the illuminated model and the image in the camera is modulated by the interference pattern. The interference pattern depends on the oil-thickness distribution on the observed surface, and this distribution can be extracted through analysis of the image acquired by the camera. The oil-film technique is augmented by a tracer technique for observing the streamline pattern. To make the streamlines visible, small dots of fluorescentchalk/oil mixture are placed on the model just before a test. During the test, the chalk particles are embedded in the oil flow and produce chalk streaks that mark the streamlines. The instantaneous rate of thinning of the oil film at a given position on the surface of the model can be expressed as a function of the instantaneous thickness, the skin-friction distribution on the surface, and the streamline pattern on the surface; the functional relationship is expressed by a mathematical model that is nonlinear in the oil-film thickness and is known simply as the thin-oil-film equation. From the

In vivo measurement of skin microrelief using photometric stereo in the presence of interreflections.

PubMed

Sohaib, Ali; Farooq, Abdul R; Atkinson, Gary A; Smith, Lyndon N; Smith, Melvyn L; Warr, Robert

2013-03-01

This paper proposes and describes an implementation of a photometric stereo-based technique for in vivo assessment of three-dimensional (3D) skin topography in the presence of interreflections. The proposed method illuminates skin with red, green, and blue colored lights and uses the resulting variation in surface gradients to mitigate the effects of interreflections. Experiments were carried out on Caucasian, Asian, and African American subjects to demonstrate the accuracy of our method and to validate the measurements produced by our system. Our method produced significant improvement in 3D surface reconstruction for all Caucasian, Asian, and African American skin types. The results also illustrate the differences in recovered skin topography due to the nondiffuse bidirectional reflectance distribution function (BRDF) for each color illumination used, which also concur with the existing multispectral BRDF data available for skin.

A new skin friction balance and selected measurements

NASA Technical Reports Server (NTRS)

Vakili, A. D.

1992-01-01

A new skin friction balance with moving belt has been developed for measurement of the surface shear stress component in the direction of belt motion. The device is described in this paper with typical measurement results. This instrument is symmetric in design with small moving mass negligible internal friction. It is 3.8 cm high, 3.8 cm long and 2.1 cm wide, with the sensing surface 0.7 cm wide and 1.5 cm long, and it can be made in various sizes. The unique design of this instrument has reduced some of the errors associated with conventional floating-element balances. The instrument can use various sensing systems and the output signal is a linear function of the wall shear stress. Measurements show good agreement with data obtained by the floating element balances and flat plate prediction techniques. Dynamic measurements have been made in a limited range. The overall uncertainty of measurement is estimated to be +/- 2 percent.

In-vivo dynamic characterization of microneedle skin penetration using optical coherence tomography

NASA Astrophysics Data System (ADS)

Enfield, Joey; O'Connell, Marie-Louise; Lawlor, Kate; Jonathan, Enock; O'Mahony, Conor; Leahy, Martin

2010-07-01

The use of microneedles as a method of circumventing the barrier properties of the stratum corneum is receiving much attention. Although skin disruption technologies and subsequent transdermal diffusion rates are being extensively studied, no accurate data on depth and closure kinetics of microneedle-induced skin pores are available, primarily due to the cumbersome techniques currently required for skin analysis. We report on the first use of optical coherence tomography technology to image microneedle penetration in real time and in vivo. We show that optical coherence tomography (OCT) can be used to painlessly measure stratum corneum and epidermis thickness, as well as microneedle penetration depth after microneedle insertion. Since OCT is a real-time, in-vivo, nondestructive technique, we also analyze skin healing characteristics and present quantitative data on micropore closure rate. Two locations (the volar forearm and dorsal aspect of the fingertip) have been assessed as suitable candidates for microneedle administration. The results illustrate the applicability of OCT analysis as a tool for microneedle-related skin characterization.

Farmers sun exposure, skin protection and public health campaigns: An Australian perspective.

PubMed

Smit-Kroner, Christel; Brumby, Susan

2015-01-01

Non-melanoma skin cancer is a common and costly cancer in agricultural populations. Prevention and early detection are an effective way to decrease the burden of disease and associated costs. To examine sun exposure and skin protection practices in agricultural workers and farmers a thematic review of the literature between 1983 and 2014 was undertaken. Comparison between studies was complicated by differences in study design, definitions of skin protection, and analytic methods used. Farmers are the most exposed to harmful ultraviolet (UV) radiation of all outdoor workers and the level of reported skin protection by farmers is suboptimal. Years of public health campaigns have failed to adequately address farmers' specific needs. Increased rates of skin cancer and subsequent higher costs are expected. Estimates of sun exposure and skin protection practice indicate that protective clothing is the most promising avenue to improve on farmers' skin protection. Early detection needs to be part of public health campaigns. This review explores the quantitative data about Australian farmers and their skin protective behaviours. We investigate what the documented measurable effect of the public health campaign Slip!Slop!Slap! has had on agricultural workers and farmers and make recommendations for future focus.

Quantitative measurement of marginal disintegration of ceramic inlays.

PubMed

Hayashi, Mikako; Tsubakimoto, Yuko; Takeshige, Fumio; Ebisu, Shigeyuki

2004-01-01

The objectives of this study include establishing a method for quantitative measurement of marginal change in ceramic inlays and clarifying their marginal disintegration in vivo. An accurate CCD optical laser scanner system was used for morphological measurement of the marginal change of ceramic inlays. The accuracy of the CCD measurement was assessed by comparing it with microscopic measurement. Replicas of 15 premolars restored with Class II ceramic inlays at the time of placement and eight years after restoration were used for morphological measurement by means of the CCD laser scanner system. Occlusal surfaces of the restored teeth were scanned and cross-sections of marginal areas were computed with software. Marginal change was defined as the area enclosed by two profiles obtained by superimposing two cross-sections of the same location at two different times and expressing the maximum depth and mean area of the area enclosed. The accuracy of this method of measurement was 4.3 +/- 3.2 microm in distance and 2.0 +/- 0.6% in area. Quantitative marginal changes for the eight-year period were 10 x 10 microm in depth and 50 x 10(3) microm2 in area at the functional cusp area and 7 x 10 microm in depth and 28 x 10(3) microm2 in area at the non-functional cusp area. Marginal disintegration at the functional cusp area was significantly greater than at the non-functional cusp area (Wilcoxon signed-ranks test, p < 0.05). This study constitutes a quantitative measurement of in vivo deterioration in marginal adaptation of ceramic inlays and indicates that occlusal force may accelerate marginal disintegration.

Supraclavicular skin temperature as a measure of 18F-FDG uptake by BAT in human subjects.

PubMed

Boon, Mariëtte R; Bakker, Leontine E H; van der Linden, Rianne A D; Pereira Arias-Bouda, Lenka; Smit, Frits; Verberne, Hein J; van Marken Lichtenbelt, Wouter D; Jazet, Ingrid M; Rensen, Patrick C N

2014-01-01

Brown adipose tissue (BAT) has emerged as a novel player in energy homeostasis in humans and is considered a potential new target for combating obesity and related diseases. The current 'gold standard' for quantification of BAT volume and activity is cold-induced 18F-FDG uptake in BAT. However, use of this technique is limited by cost and radiation exposure. Given the fact that BAT is a thermogenic tissue, mainly located in the supraclavicular region, the aim of the current study was to investigate whether cold-induced supraclavicular skin temperature and core body temperature may be alternative markers of BAT activation in humans. BAT volume and activity were measured in 24 healthy lean adolescent males (mean age 24.1±0.8 years), using cold-induced 18F-FDG uptake with PET-CT. Core body temperature was measured continuously in the small intestine with use of an ingestible telemetric capsule and skin temperature was measured by eighteen wireless iButtons attached to the skin following ISO-defined locations. Proximal and distal (hand/feet) skin temperatures markedly decreased upon cold exposure, while supraclavicular skin temperature significantly increased (35.2±0.1 vs. 35.5±0.1°C, p = 0.001). Furthermore, cold-induced supraclavicular skin temperature positively correlated with both total (R2 = 0.28, P = 0.010) and clavicular BAT volume (R2 = 0.20, P = 0.030) and clavicular SUVmax (R2 = 0.27, P = 0.010), while core body temperature did not. Supraclavicular skin temperature as measured by iButtons may have predictive value for BAT detection in adult humans. This is highly desirable considering the increasing interest in pharmacological interventions to stimulate BAT in human subjects. NTR 2473.

Supraclavicular Skin Temperature as a Measure of 18F-FDG Uptake by BAT in Human Subjects

PubMed Central

van der Linden, Rianne A. D.; Pereira Arias-Bouda, Lenka; Smit, Frits; Verberne, Hein J.; van Marken Lichtenbelt, Wouter D.

2014-01-01

Background Brown adipose tissue (BAT) has emerged as a novel player in energy homeostasis in humans and is considered a potential new target for combating obesity and related diseases. The current ‘gold standard’ for quantification of BAT volume and activity is cold-induced 18F-FDG uptake in BAT. However, use of this technique is limited by cost and radiation exposure. Given the fact that BAT is a thermogenic tissue, mainly located in the supraclavicular region, the aim of the current study was to investigate whether cold-induced supraclavicular skin temperature and core body temperature may be alternative markers of BAT activation in humans. Subjects/Methods BAT volume and activity were measured in 24 healthy lean adolescent males (mean age 24.1±0.8 years), using cold-induced 18F-FDG uptake with PET-CT. Core body temperature was measured continuously in the small intestine with use of an ingestible telemetric capsule and skin temperature was measured by eighteen wireless iButtons attached to the skin following ISO-defined locations. Results Proximal and distal (hand/feet) skin temperatures markedly decreased upon cold exposure, while supraclavicular skin temperature significantly increased (35.2±0.1 vs. 35.5±0.1°C, p = 0.001). Furthermore, cold-induced supraclavicular skin temperature positively correlated with both total (R2 = 0.28, P = 0.010) and clavicular BAT volume (R2 = 0.20, P = 0.030) and clavicular SUVmax (R2 = 0.27, P = 0.010), while core body temperature did not. Conclusions Supraclavicular skin temperature as measured by iButtons may have predictive value for BAT detection in adult humans. This is highly desirable considering the increasing interest in pharmacological interventions to stimulate BAT in human subjects. Trial Registration NTR 2473 PMID:24922545

The radiation dose from a proposed measurement of arsenic and selenium in human skin

NASA Astrophysics Data System (ADS)

Gherase, Mihai R.; Mader, Joanna E.; Fleming, David E. B.

2010-09-01

Dose measurements following 10 min irradiations with a portable x-ray fluorescence spectrometer composed of a miniature x-ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table-top setup of the spectrometer was used for all measurements. The setup included a stainless steel lid which served as a radiation shield. Two rectangular polyethylene skin/soft tissue phantoms with two cylindrical plaster of Paris bone phantoms were used to study the effect of x-ray beam attenuation and backscatter on the measured dose. Eight different irradiation experiments were performed. The average dose rate values measured with TLD chips within a 1 × 1 cm2 area were between 4.8 and 12.8 mGy min-1. The equivalent dose for a 1 × 1 cm2 skin area was estimated to be 13.2 mSv. The maximum measured dose rate values with a single TLD chip were between 7.5 and 25.1 mGy min-1. The effective dose corresponding to a proposed arsenic/selenium skin measurement was estimated to be 0.13 µSv for a 2 min irradiation.

Skin friction under pressure. The role of micromechanics

NASA Astrophysics Data System (ADS)

Leyva-Mendivil, Maria F.; Lengiewicz, Jakub; Limbert, Georges

2018-03-01

The role of contact pressure on skin friction has been documented in multiple experimental studies. Skin friction significantly raises in the low-pressure regime as load increases while, after a critical pressure value is reached, the coefficient of friction of skin against an external surface becomes mostly insensitive to contact pressure. However, up to now, no study has elucidated the qualitative and quantitative nature of the interplay between contact pressure, the material and microstructural properties of the skin, the size of an indenting slider and the resulting measured macroscopic coefficient of friction. A mechanistic understanding of these aspects is essential for guiding the rational design of products intended to interact with the skin through optimally-tuned surface and/or microstructural properties. Here, an anatomically-realistic 2D multi-layer finite element model of the skin was embedded within a computational contact homogenisation procedure. The main objective was to investigate the sensitivity of macroscopic skin friction to the parameters discussed above, in addition to the local (i.e. microscopic) coefficient of friction defined at skin asperity level. This was accomplished via the design of a large-scale computational experiment featuring 312 analyses. Results confirmed the potentially major role of finite deformations of skin asperities on the resulting macroscopic friction. This effect was shown to be modulated by the level of contact pressure and relative size of skin surface asperities compared to those of a rigid slider. The numerical study also corroborated experimental observations concerning the existence of two contact pressure regimes where macroscopic friction steeply and non-linearly increases up to a critical value, and then remains approximately constant as pressure increases further. The proposed computational modelling platform offers attractive features which are beyond the reach of current analytical models of skin

Skin autofluorescence reflects individual seasonal UV exposure, skin photodamage and skin cancer development in organ transplant recipients.

PubMed

Togsverd-Bo, Katrine; Philipsen, Peter Alshede; Hædersdal, Merete; Wulf, Hans Christian Olsen

2018-01-01

Ultraviolet radiation (UVR)-induced skin cancers varies among organ transplant recipients (OTRs). To improve individual risk assessment of skin cancer, objectively quantified skin photodamage is needed. We measured personal UVR-exposure dose in OTRs and assessed the relation between individual UVR exposure, skin cancer and objectively measured photodamage in terms of skin autofluorescence, pigmentation, and black light-evaluated solar lentigines. Danish OTRs with (n=15) and without a history of skin cancer (n=15) kept sun diaries from May to September and wore personal dosimeters recording time-stamped UVR doses in standard erythema doses (SED). Photodamage was quantified as skin autofluorescence with excitation at 370nm (F370) and 430nm (F430), skin pigmentation (pigment protection factor, PPF), and black light-evaluated solar lentigines. OTRs with skin cancer received a higher UVR dose than OTRs without skin cancer (median 116 SED vs. 67 SED, p=0.07) and UVR exposure doses were correlated with increased PPF (p=0.052) and F370 on the shoulder (F370 shoulder ) (p=0.04). We found that skin cancer was associated with F370 shoulder (OR 10.53, CI 3.3-31,938; p=0.018) and time since transplantation (OR 1.34, CI 0.95-1.91, p=0.097). A cut-off at 7.2 arbitrary units, 89% of OTRs with skin cancer had F370 shoulder values above 7.2 arbitrary units and F370 shoulder was additionally related to patient age (p=0.09) and black light-evaluated solar lentigines (p=0.04). F370 autofluorescence indicates objectively measured photodamage and may be used for individual risk assessment of skin cancer development in OTRs. Copyright © 2017. Published by Elsevier B.V.

Measurements of Skin Friction of the Compressible Turbulent Boundary Layer on a Cone with Foreign Gas Injection

NASA Technical Reports Server (NTRS)

Pappas, Constantine C.; Ukuno, Arthur F.

1960-01-01

Measurements of average skin friction of the turbulent boundary layer have been made on a 15deg total included angle cone with foreign gas injection. Measurements of total skin-friction drag were obtained at free-stream Mach numbers of 0.3, 0.7, 3.5, and 4.7 and within a Reynolds number range from 0.9 x 10(exp 6) to 5.9 x 10(exp 6) with injection of helium, air, and Freon-12 (CCl2F2) through the porous wall. Substantial reductions in skin friction are realized with gas injection within the range of Mach numbers of this test. The relative reduction in skin friction is in accordance with theory-that is, the light gases are most effective when compared on a mass flow basis. There is a marked effect of Mach number on the reduction of average skin friction; this effect is not shown by the available theories. Limited transition location measurements indicate that the boundary layer does not fully trip with gas injection but that the transition point approaches a forward limit with increasing injection. The variation of the skin-friction coefficient, for the lower injection rates with natural transition, is dependent on the flow Reynolds number and type of injected gas; and at the high injection rates the skin friction is in fair agreement with the turbulent boundary layer results.

Measurement of contaminant removal from skin using a portable fluorescence scanning system.

PubMed

Hession, Helena; Byrne, Miriam; Cleary, S; Andersson, K G; Roed, J

2006-01-01

The residence time of particulate contamination on the human body is a factor that has an important impact on the accuracy of exposure assessment in the aftermath of an accidental release of radionuclides to the atmosphere. Measurements of particle clearance from human skin were made using an illumination system to excite fluorescence in labelled silica particles and a CCD camera and image processing system to detect this fluorescence. The illumination system consists of high-intensity light emitting diodes (LEDS) of suitable wavelengths arranged on a portable stand. The physically small size of the LEDs allows them to be positioned close to the fluorescing surface, thus maximising the fluorescent signal that can be obtained. The limit of detection was found to be 50 microg of tracer particle per cm2. Experiments were carried out to determine the clearance rates of 10 microm and 3 microm particles from the skin. Results show that, in the absence of any mechanical rubbing of the skin, the clearance of particles from the skin followed an approximately exponential decay with a half-time of 1.5-7.8 h. Skin hairiness and degree of human movement were found, in addition to particle size, to have an important influence on particle fall-off rate.

In multiple situational light settings, visual observation for skin colour assessment is comparable with colorimeter measurement.

PubMed

Wright, C Y; Wilkes, M; du Plessis, J L; Reeder, A I; Albers, P N

2016-08-01

Finding inexpensive and reliable techniques for assessing skin colour is important, given that it is related to several adverse human health outcomes. Visual observation is considered a subjective approach assessment and, even when made by trained assessor, concern has been raised about the need for controlled lighting in the study venue. The aim of this study is to determine whether visual skin colour assessments correlate with objective skin colour measurements in study venues with different lighting types and configurations. Two trained investigators, with confirmed visual acuity, visually classified the inner, upper arm skin colour of 556 adults using Munsell(®) colour classifications converted to Individual Typology Angle (°ITA) values based on published data. Skin colour at the same anatomic site was also measured using a colorimeter. Each participant was assessed in one of 10 different buildings, each with a different study day. Munsell(®) -derived °ITA values were compared to colorimeter °ITA values for the full sample and by building/day. We found a strong positive, monotonic correlation between Munsell(®) derived °ITA values and colorimeter °ITA values for all participants (Spearman ρ = 0.8585, P < 0.001). Similar relationships were found when Munsell(®) and colorimeter °ITA values were compared for participants assessed in the same building for all 10 buildings (Spearman ρ values ranged from 0.797 to 0.934, all correlations were statistically significant at P < 0.001). It is possible to visually assess individual skin colour in multiple situational lighting settings and retrieve results that are comparable with objective measurements of skin colour. This was true for individuals of varying population groups and skin pigmentation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Quantitative force measurements in liquid using frequency modulation atomic force microscopy

NASA Astrophysics Data System (ADS)

Uchihashi, Takayuki; Higgins, Michael J.; Yasuda, Satoshi; Jarvis, Suzanne P.; Akita, Seiji; Nakayama, Yoshikazu; Sader, John E.

2004-10-01

The measurement of short-range forces with the atomic force microscope (AFM) typically requires implementation of dynamic techniques to maintain sensitivity and stability. While frequency modulation atomic force microscopy (FM-AFM) is used widely for high-resolution imaging and quantitative force measurements in vacuum, quantitative force measurements using FM-AFM in liquids have proven elusive. Here we demonstrate that the formalism derived for operation in vacuum can also be used in liquids, provided certain modifications are implemented. To facilitate comparison with previous measurements taken using surface forces apparatus, we choose a model system (octamethylcyclotetrasiloxane) that is known to exhibit short-ranged structural ordering when confined between two surfaces. Force measurements obtained are found to be in excellent agreement with previously reported results. This study therefore establishes FM-AFM as a powerful tool for the quantitative measurement of forces in liquid.

Direct measurement of skin friction with a new instrument

NASA Technical Reports Server (NTRS)

Vakili, A. D.; Wu, J. M.

1986-01-01

The design and performance of a small belt-type skin-friction gage to measure wall shear-stress coefficients in wind-tunnel testing are described, summarizing the report of Vakili and Wu (1982). The sensor employs a flexible belt of variable surface characteristics; this belt, wrapped tightly around two cylinders mounted on frictionless flexures, is equipped with strain gages to estimate the deflection of the belt by the flow. An alternative approach uses IR illumination, optical fibers, and a photosensitive transistor, permitting direct measurement of the belt deflection. Drawings, diagrams, and graphs of sample data are provided.

Relation between skin micro-topography, roughness, and skin age.

PubMed

Trojahn, C; Dobos, G; Schario, M; Ludriksone, L; Blume-Peytavi, U; Kottner, J

2015-02-01

The topography of the skin surface consists of lines, wrinkles, and scales. Primary and secondary lines form a network like structure that may be identified as polygons. Skin surface roughness measurements are widely applied in dermatological research and practice but the relation between roughness parameters and their anatomical equivalents are unclear. This study aimed to investigate whether the number of closed polygons (NCP) per measurement field can be used as a reliable parameter to measure skin surface topography. For this purpose, we analysed the relation between skin surface roughness parameters and NCP in different age groups. Images of the volar forearm skin of 38 subjects (14 children, 12 younger, and 12 older adults) were obtained with the VisioScan VC98. The NCP was counted by three independent researchers and selected roughness parameters were measured. Interrater reliability of counting the number of closed polygons and correlations between NCP, roughness parameters, and age were calculated. The mean NCP/mm² in children was 3.1 (SD 1.1), in younger adults 1.0 (SD 0.7), and in older adults 1.0 (SD 0.9). The interrater reliability was 0.9. A negative correlation of NCP/mm² with age was observed, whereas measured roughness parameters were positively associated with age. NCP/mm² was weakly related to skin roughness. The NCP/mm² is a reproducible parameter for characterizing the skin surface topography. It is proposed as an additional parameter in dermatological research and practice because it represents distinct aspects of the cutaneous profile not covered by established roughness parameters. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A general way for quantitative magnetic measurement by transmitted electrons

NASA Astrophysics Data System (ADS)

Song, Dongsheng; Li, Gen; Cai, Jianwang; Zhu, Jing

2016-01-01

EMCD (electron magnetic circular dichroism) technique opens a new door to explore magnetic properties by transmitted electrons. The recently developed site-specific EMCD technique makes it possible to obtain rich magnetic information from the Fe atoms sited at nonequivalent crystallographic planes in NiFe2O4, however it is based on a critical demand for the crystallographic structure of the testing sample. Here, we have further improved and tested the method for quantitative site-specific magnetic measurement applicable for more complex crystallographic structure by using the effective dynamical diffraction effects (general routine for selecting proper diffraction conditions, making use of the asymmetry of dynamical diffraction for design of experimental geometry and quantitative measurement, etc), and taken yttrium iron garnet (Y3Fe5O12, YIG) with more complex crystallographic structure as an example to demonstrate its applicability. As a result, the intrinsic magnetic circular dichroism signals, spin and orbital magnetic moment of iron with site-specific are quantitatively determined. The method will further promote the development of quantitative magnetic measurement with high spatial resolution by transmitted electrons.

Seasonal skin colour changes in a sample teenage population measured by reflection spectrophotometry

NASA Astrophysics Data System (ADS)

Stringer, M. R.; Cruse-Sawyer, J. E.

2007-11-01

As part of a classroom-based research project, reflectance spectra from the skin of a group of teenage school students were recorded over a four-month period, from early spring to mid-summer. The relative changes in skin colour during the course of the study were quantified by integrating over the full wavelength range of the normalized reflectance spectra. Measurements made upon the inner forearm and the back of the hand produce results which indicate a decrease in total reflectance (increase in absorption) corresponding to different levels of tanning for limited and extended exposure to ambient sunlight, respectively. The rate of change of skin colour qualitatively matches that of the solar illuminance.

Skin sensitisation quantitative risk assessment (QRA) based on aggregate dermal exposure to methylisothiazolinone in personal care and household cleaning products.

PubMed

Ezendam, J; Bokkers, B G H; Bil, W; Delmaar, J E

2018-02-01

Contact allergy to preservatives is an important public health problem. Ideally, new substances should be evaluated for the risk on skin sensitisation before market entry, for example by using a quantitative risk assessment (QRA) as developed for fragrances. As a proof-of-concept, this QRA was applied to the preservative methylisothiazolinone (MI), a common cause of contact allergy. MI is used in different consumer products, including personal care products (PCPs) and household cleaning products (HCPs). Aggregate exposure to MI in PCPs and HCPs was therefore assessed with the Probabilistic Aggregated Consumer Exposure Model (PACEM). Two exposure scenarios were evaluated: scenario 1 calculated aggregate exposure on actual MI product concentrations before the restricted use in PCPs and scenario 2 calculated aggregate exposure using the restrictions for MI in PCPs. The QRA for MI showed that in scenarios 1 and 2, the proportion of the population at risk for skin sensitisation is 0.7% and 0.5%, respectively. The restricted use of MI in PCPs does not seem very effective in lowering the risk on skin sensitization. To conclude, it is important to consider aggregate exposure from the most important consumer products into consideration in the risk assessment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modeling Electronic Skin Response to Normal Distributed Force.

PubMed

Seminara, Lucia

2018-02-03

The reference electronic skin is a sensor array based on PVDF (Polyvinylidene fluoride) piezoelectric polymers, coupled to a rigid substrate and covered by an elastomer layer. It is first evaluated how a distributed normal force (Hertzian distribution) is transmitted to an extended PVDF sensor through the elastomer layer. A simplified approach based on Boussinesq's half-space assumption is used to get a qualitative picture and extensive FEM simulations allow determination of the quantitative response for the actual finite elastomer layer. The ultimate use of the present model is to estimate the electrical sensor output from a measure of a basic mechanical action at the skin surface. However this requires that the PVDF piezoelectric coefficient be known a-priori. This was not the case in the present investigation. However, the numerical model has been used to fit experimental data from a real skin prototype and to estimate the sensor piezoelectric coefficient. It turned out that this value depends on the preload and decreases as a result of PVDF aging and fatigue. This framework contains all the fundamental ingredients of a fully predictive model, suggesting a number of future developments potentially useful for skin design and validation of the fabrication technology.

Registered report: measuring unconscious deception detection by skin temperature

PubMed Central

van ’ t Veer, Anna E.; Stel, Mariëlle; van Beest, Ilja; Gallucci, Marcello

2014-01-01

Findings from the deception detection literature suggest that although people are not skilled in consciously detecting a liar, they may intuit that something about the person telling a lie is off. In the current proposal, we argue that observing a liar influences the observer’s physiology even though the observer may not be consciously aware of being lied to (i.e., the observers’ direct deception judgment does not accurately differentiate between liars and truth-tellers). To test this hypothesis, participants’ finger temperature will be measured while they watch videos of persons who are either honest or dishonest about their identity. We hypothesize that skin temperature will be lower when observing a liar than when observing a truth-teller. Additionally, we test whether perceiving a liar influences finger skin temperature differently when an individual is, or is not, alerted to the possibility of deceit. We do this by varying participants’ awareness of the fact that they might be lied to. Next to measuring physiological responses to liars and truth-tellers, self-reported direct and indirect veracity judgments (i.e., trustworthiness and liking) of the target persons will be assessed. We hypothesize that indirect veracity judgments will better distinguish between liars and truth-tellers than direct veracity judgments. PMID:24904461

The calibration of video cameras for quantitative measurements

NASA Technical Reports Server (NTRS)

Snow, Walter L.; Childers, Brooks A.; Shortis, Mark R.

1993-01-01

Several different recent applications of velocimetry at Langley Research Center are described in order to show the need for video camera calibration for quantitative measurements. Problems peculiar to video sensing are discussed, including synchronization and timing, targeting, and lighting. The extension of the measurements to include radiometric estimates is addressed.

In vivo measurements of the influence of the skin on cerebral oxygenation changes measured with near-infrared spectrophotometry (NIRS)

NASA Astrophysics Data System (ADS)

Klaessens, John H. G. M.; van Os, Sandra H. G.; Hopman, Jeroen C. W.; Liem, K. D.; van de Bor, Margot; Thijssen, Johan M.

2004-07-01

Goal: To investigate the influence of skin on the accuracy and precision of regional cerebral oxygenation measurements using CW-NIRS and to reduce the inter individual variability of NIRS measurements by normalization with data from an extra wavelength. Method: Three piglets (7.8-9.3 kg) were anesthetized, paralyzed and mechanically ventilated. Receiving optodes were placed over the left and right hemisphere (C3, C4 EEG placement code) and one emitting optode on Cz position (optode distance=1.8cm). Optical densities (OD) were measured for 3 wavelengths (767, 850, 905 nm) (OXYMON) during stable normoxic, mild and deep hypoxemic conditions (SaO2=100%, 80% and 60%) of one minute in each region. This was repeated 3 times: all optodes with skin (condition 1); one receiving optode directly on the skull (2); emitting and also receiving optode on the skull (3). The absolute cO2Hb, cHHb, ctHb concentrations (μmol/L) were calculated from the OD's and changes with respect to the SaO2=100% condition were estimated. Because ODs varied over a large range, the light intensity was externally attenuated to adapt to the range of the spectrophotometer. The data were then corrected for these attenuation effects and for pathlength changes caused by skin removal using the OD at the independent wavelength (λ=975nm). Results: Removal of the skin resulted in an increase of the absorption values (average 0.25 OD in condition 2 and 0.42 OD in condition 3 with respect to condition 1). The change from normoxic to medium, and to deep hypoxic conditions produced a decrease of cO2Hb (-15, and -29 μmol/L, respectively), an increase in cHHb (+16, and +35 μmol/L) and in ctHb (+1, and +5 μmol/L). Total skin removal yielded an extra change in cO2Hb (-5, -1 μmol/L), cHHb (+8, +9 μmol/L), and ctHb (+3, +8 μmol /L). The coefficient of variability of the absolute concentration changes was considerably decreased by the normalization of densities by the density obtained at 795 nm. Conclusion: Skin

Biomedical engineering meets acupuncture - development of a miniaturized 48-channel skin impedance measurement system for needle and laser acupuncture

PubMed Central

2010-01-01

Background Due to controversially discussed results in scientific literature concerning changes of electrical skin impedance before and during acupuncture a new measurement system has been developed. Methods The prototype measures and analyzes the electrical skin impedance computer-based and simultaneously in 48 channels within a 2.5×3.5 cm matrix. Preliminary measurements in one person were performed using metal needle and violet laser (405 nm) acupuncture at the acupoint Kongzui (LU6). The new system is an improvement on devices previously developed by other researchers for this purpose. Results Skin impedance in the immediate surroundings of the acupoint was lowered reproducibly following needle stimulation and also violet laser stimulation. Conclusions A new instrumentation for skin impedance measurements is presented. The following hypotheses suggested by our results will have to be tested in further studies: Needle acupuncture causes significant, specific local changes of electrical skin impedance parameters. Optical stimulation (violet laser) at an acupoint causes direct electrical biosignal changes. PMID:21092296

The investigation of the skin characteristics of males focusing on gender differences, skin perception, and skin care habits.

PubMed

Mizukoshi, Koji; Akamatsu, Hisashi

2013-05-01

Various studies have examined the properties of male skin. However, because these studies mostly involved simple measurement with non-invasive devices, a lack of understanding of the properties of male skin remains. In this study, we focused and investigated not only on simple instrumental measurements but also on gender differences and men's subjective perceptions of skin and daily skin care habits. Barrier function depends on corneocyte maturation level as well as sebum amount. Irrespective of the skin type, a high percentage of male subjects perceived a 'tacky feeling'. However, the percentage of men perceiving a 'shiny feeling' differed by skin type. Furthermore, there was a relationship between skin care habits and skin function. Men who did not perform a daily skincare regimen demonstrated a significantly higher sebum amount and transepidermal water loss value than those who did perform a daily skincare regimen. The results of this study indicate that male skin has two specific characteristics: impaired barrier function because of the excess amount of sebum and a lack of an appropriate skin care regimen because of the 'tacky feeling' caused by excess sebum. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

The NPe6 fluorescence measurements by using a fluorescence sensing system for skin photosensitivity risk assessment after photodynamic therapy

NASA Astrophysics Data System (ADS)

Ohtani, Keishi; Usuda, Jitsu; Ogawa, Emiyu; Maehara, Sachio; Imai, Kentaro; Inoue, Tatsuya; Hagiwara, Masaru; Kakihana, Masatoshi; Kajiwara, Naohiro; Ohira, Tatsuo; Arai, Tsunenori; Ikeda, Norihiko

2018-02-01

Background: Skin photosensitivity is a major side effect of photodynamic therapy (PDT). It is induced by the photosensitizer remaining in the skin. It is usually rapidly metabolized by the liver, but the pharmacokinetic profile varies widely among individuals. This makes it difficult to predict the incidence of skin photosensitivity. Therefore, we conducted a prospective study to investigate whether the NPe6 fluorescence intensity in skin after NPe6-PDT could be measured safely in human patients using a fluorescence sensing system for judging the risk of skin photosensitivity. Methods: The NPe6 fluorescence measurements using a constructed fluorescence sensing system at the inside of the arm were acquired prior to and 5 and 10 minutes after NPe6 administration as well as at the time of PDT (4-5 hours after administration), at discharge (2 or 3 days after PDT), and at 1 or 2 weeks after PDT. Participants were interviewed as to whether they had any complications at 2 weeks after PDT. Results: Nine male patients and one female patient entered this study. All of the measurements of NPe6 fluorescence in the skin could be obtained without any complications. The spectral peak was detected at the time of discharge (2-3 days after administration) in most cases and it decreased at 1 or 2 weeks after PDT. Conclusions: The fluorescence of NPe6 in the skin could be detected feasibly using the fluorescence sensing system in human patients. Measuring fluorescence intensity in the skin might be useful to predict the incidence of skin photosensitivity after PDT.

Ionic skin.

PubMed

Sun, Jeong-Yun; Keplinger, Christoph; Whitesides, George M; Suo, Zhigang

2014-12-03

Electronic skins (i.e., stretchable sheets of distributed sensors) report signals using electrons, whereas natural skins report signals using ions. Here, ionic conductors are used to create a new type of sensory sheet, called "ionic skin". Ionic skins are highly stretchable, transparent, and biocompatible. They readily measure strains from 1% to 500%, and pressures as low as 1 kPa. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design and validation of a questionnaire for measuring perceived risk of skin cancer.

PubMed

Morales-Sánchez, M A; Peralta-Pedrero, M L; Domínguez-Gómez, M A

2014-04-01

A perceived risk of cancer encourages preventive behavior while the lack of such a perception is a barrier to risk reduction. There are no instruments in Spanish to measure this perceived risk and thus quantify response to interventions for preventing this disease at a population level. The aim of this study was to design and validate a self-administered questionnaire for measuring the perceived risk of skin cancer. A self-administered questionnaire with a visual Likert-type scale was designed based on the results of the analysis of the content of a survey performed in 100 patients in the Dr. Ladislao de la Pascua Skin Clinic, Distrito Federal México, Mexico. Subsequently, the questionnaire was administered to a sample of 359 adult patients who attended the clinic for the first time. As no gold standard exists for measuring the perceived risk of skin cancer, the construct was validated through factor analysis. The final questionnaire had 18 items. The internal consistency measured with Cronbach α was 0.824 overall. In the factor analysis, 4 factors (denoted as affective, behavioral, severity, and susceptibility) and an indicator of risk accounted for 65.133% of the variance. The psychometric properties of the scale were appropriate for measuring the perception of risk in adult patients (aged 18 years or more) who attended the dermatology clinic. Copyright © 2013 Elsevier España, S.L. and AEDV. All rights reserved.

3-D profilometer using a CCD linear image sensor: application to skin surface topography measurement.

PubMed

Nita, D; Mignot, J; Chuard, M; Sofa, M

1998-08-01

Measurement of cutaneous surface topography can be made by three-dimensional (3-D) profilometry. Different equipment is used for this measurement. The magnitude of the vertical scale required, which can vary from several tens of micrometers (microrelief) to several millimeters (skin pathologies), depends also on the precision required and the duration of acquisition time. Over the last few years, different apparatuses have been produced, with a vertical range that is most frequently used for classical industrial applications, i.e., 0-1000 μm. The system developed here has a wide range of about 7 mm and is accurate enough to analyse each of the different skin surfaces that fall in this range without changing magnification. An optical principle, operating without any contact with a skin replica, allows a precise measurement with a high scanning speed. The profilometer has a vertical sensitivity of 4 μm within a vertical range of 7 mm. This sensitivity is lower than that of a mechanical or focusing profilometer, but the vertical range is wider. The system has several advantages: because of its verticale range, it can measure large surfaces with great roughness variations; the initial position of the replica beneath the profilometer must be within the 7 mm vertical range; and skin topography can be quantified, without contact, in a short time.

Correlation of Handheld Infrared Skin Thermometer and Infrared Videothermography Device for Measurement of Corneal Temperature.

PubMed

Oztas, Zafer; Barut Selver, Ozlem; Akkin, Cezmi; Canturk, Ecem; Afrashi, Filiz

2016-05-01

In our study, we aimed to investigate the correlation of handheld infrared skin thermometer and videothermography device for the measurement of corneal temperature. Forty healthy individuals (80 eyes) were enrolled to the study. Participants underwent a detailed ophthalmologic examination and medical history review for excluding any ocular and systemic diseases. The measurements of the central corneal temperature were performed in a room having constant temperature, humidity, and brightness levels. To avoid any variability, all the temperature measurements were performed in the same examination room by a single examiner. The temperature was measured with a handheld infrared skin thermometer (MEDISANA, FTN) from the corneal surface. The same instrument was also used to measure the subjects' body temperature. Moreover, the subjects underwent the corneal temperature measurement by a noncontact videothermography device (Optris PI 450; Optris GmbH). The male to female ratio was 19:21 among the subjects. The mean age was 25.1±4.7 years. The mean body temperature was 36.93±0.33°C. The mean corneal temperatures measured by the handheld infrared skin thermometer and the ocular videothermography device were 36.94±0.28°C and 35.61±0.61°C, respectively (P<0.01). The mean temperature difference was 1.34±0.57°C, with a 95% confidence interval. There was a moderate correlation between the corneal temperatures measured by the 2 devices in the right, the left eyes, and both eyes, respectively (P=0.450, 0.539, 0.490). Handheld infrared skin thermometers can be used for the evaluation of the corneal temperature. These devices may provide a simple, practical, and cheaper way to detect the corneal temperature, and the widely performed corneal temperature measurements may afford us to understand the temperature variability in numerous ocular conditions in a better way.

Confocal spectroscopic imaging measurements of depth dependent hydration dynamics in human skin in-vivo

NASA Astrophysics Data System (ADS)

Behm, P.; Hashemi, M.; Hoppe, S.; Wessel, S.; Hagens, R.; Jaspers, S.; Wenck, H.; Rübhausen, M.

2017-11-01

We present confocal spectroscopic imaging measurements applied to in-vivo studies to determine the depth dependent hydration profiles of human skin. The observed spectroscopic signal covers the spectral range from 810 nm to 2100 nm allowing to probe relevant absorption signals that can be associated with e.g. lipid and water-absorption bands. We employ a spectrally sensitive autofocus mechanism that allows an ultrafast focusing of the measurement spot on the skin and subsequently probes the evolution of the absorption bands as a function of depth. We determine the change of the water concentration in m%. The water concentration follows a sigmoidal behavior with an increase of the water content of about 70% within 5 μm in a depth of about 14 μm. We have applied our technique to study the hydration dynamics of skin before and after treatment with different concentrations of glycerol indicating that an increase of the glycerol concentration leads to an enhanced water concentration in the stratum corneum. Moreover, in contrast to traditional corneometry we have found that the application of Aluminium Chlorohydrate has no impact to the hydration of skin.

Some effects of finite spatial resolution on skin friction measurements in turbulent boundary layers

NASA Technical Reports Server (NTRS)

Westphal, Russell V.

1988-01-01

The effects of finite spatial resolution often cause serious errors in measurements in turbulent boundary layers, with particularly large effects for measurements of fluctuating skin friction and velocities within the sublayer. However, classical analyses of finite spatial resolution effects have generally not accounted for the substantial inhomogeneity and anisotropy of near-wall turbulence. The present study has made use of results from recent computational simulations of wall-bounded turbulent flows to examine spatial resolution effects for measurements made at a wall using both single-sensor probes and those employing two sensing volumes in a V shape. Results are presented to show the effects of finite spatial resolution on a variety of quantitites deduced from the skin friction field.

Quantitative angle-insensitive flow measurement using relative standard deviation OCT

NASA Astrophysics Data System (ADS)

Zhu, Jiang; Zhang, Buyun; Qi, Li; Wang, Ling; Yang, Qiang; Zhu, Zhuqing; Huo, Tiancheng; Chen, Zhongping

2017-10-01

Incorporating different data processing methods, optical coherence tomography (OCT) has the ability for high-resolution angiography and quantitative flow velocity measurements. However, OCT angiography cannot provide quantitative information of flow velocities, and the velocity measurement based on Doppler OCT requires the determination of Doppler angles, which is a challenge in a complex vascular network. In this study, we report on a relative standard deviation OCT (RSD-OCT) method which provides both vascular network mapping and quantitative information for flow velocities within a wide range of Doppler angles. The RSD values are angle-insensitive within a wide range of angles, and a nearly linear relationship was found between the RSD values and the flow velocities. The RSD-OCT measurement in a rat cortex shows that it can quantify the blood flow velocities as well as map the vascular network in vivo.

Quantitative angle-insensitive flow measurement using relative standard deviation OCT.

PubMed

Zhu, Jiang; Zhang, Buyun; Qi, Li; Wang, Ling; Yang, Qiang; Zhu, Zhuqing; Huo, Tiancheng; Chen, Zhongping

2017-10-30

Incorporating different data processing methods, optical coherence tomography (OCT) has the ability for high-resolution angiography and quantitative flow velocity measurements. However, OCT angiography cannot provide quantitative information of flow velocities, and the velocity measurement based on Doppler OCT requires the determination of Doppler angles, which is a challenge in a complex vascular network. In this study, we report on a relative standard deviation OCT (RSD-OCT) method which provides both vascular network mapping and quantitative information for flow velocities within a wide range of Doppler angles. The RSD values are angle-insensitive within a wide range of angles, and a nearly linear relationship was found between the RSD values and the flow velocities. The RSD-OCT measurement in a rat cortex shows that it can quantify the blood flow velocities as well as map the vascular network in vivo .

Quantitative Species Measurements In Microgravity Combustion Flames

NASA Technical Reports Server (NTRS)

Chen, Shin-Juh; Pilgrim, Jeffrey S.; Silver, Joel A.; Piltch, Nancy D.

2003-01-01

The capability of models and theories to accurately predict and describe the behavior of low gravity flames can only be verified by quantitative measurements. Although video imaging, simple temperature measurements, and velocimetry methods have provided useful information in many cases, there is still a need for quantitative species measurements. Over the past decade, we have been developing high sensitivity optical absorption techniques to permit in situ, non-intrusive, absolute concentration measurements for both major and minor flames species using diode lasers. This work has helped to establish wavelength modulation spectroscopy (WMS) as an important method for species detection within the restrictions of microgravity-based measurements. More recently, in collaboration with Prof. Dahm at the University of Michigan, a new methodology combining computed flame libraries with a single experimental measurement has allowed us to determine the concentration profiles for all species in a flame. This method, termed ITAC (Iterative Temperature with Assumed Chemistry) was demonstrated for a simple laminar nonpremixed methane-air flame at both 1-g and at 0-g in a vortex ring flame. In this paper, we report additional normal and microgravity experiments which further confirm the usefulness of this approach. We also present the development of a new type of laser. This is an external cavity diode laser (ECDL) which has the unique capability of high frequency modulation as well as a very wide tuning range. This will permit the detection of multiple species with one laser while using WMS detection.

Evaluation of sex-related changes in skin topography and structure using innovative skin testing equipment.

PubMed

Dąbrowska, M; Mielcarek, A; Nowak, I

2018-04-29

Evaluation of skin condition on the basis of parametrization and objective measurements of the parameters has become obligatory. The aim of this study was to assess sex-related changes in skin topography and structure using the skin testing equipment. The study was carried out on the group of 40 volunteers (20 females and 20 males) of the mean age 24 ± 3 years. The skin parameters were measured using 3 devices: Visioscan ®  VC 98 (skin topography), Visioline ® VL 650 (skin macro relief) and Ultrascan UC22 (ultrasound imaging of the skin). All measurements were performed on the inner part of the left forearm. The skin parameters measured revealed significant differences in skin surface and structure between females and males. The skin of all women subjects was more homogenous in its structure with the presence of more abundant superficial skin lines and wrinkles in comparison to male skin. The higher number of skin furrows in the skin of women is in agreement with literature reports claiming that men's skin has lower number of wrinkles which are deeper and more pronounced. Ultrasound imaging of the skin indicated greater thickness and lower density of the dermis of men subjects compared to those of females. Non-invasive methods of skin testing using new and advanced equipment have provided a possibility of objective parametrization and evaluation of sex-related changes in skin topography and structure. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Analysis of hemodynamics in human skin using photothermal radiometry and diffuse reflectance spectroscopy

NASA Astrophysics Data System (ADS)

Verdel, Nina; Marin, Ana; Vidovič, Luka; Milanič, Matija; Majaron, Boris

2017-07-01

We present a novel methodology for quantitative analysis of hemodynamics in human skin in vivo. Our approach combines pulsed photothermal radiometry (i.e., time-resolved measurements of midinfrared emission from sample surface after exposure to a short light pulse) and diffuse reflectance spectroscopy in visible part of the spectrum. Experimental data are fitted with predictions of a numerical model of light transport in a four-layer skin model (i.e., inverse Monte Carlo), which allows assessment of the layer thicknesses, chromophore contents (e.g., melanin, oxy- and deoxy-hemoglobin), as well as scattering properties. The performance is tested in comparison analysis of healthy skin before and during application of a blood pressure cuff (at 200 mm Hg) for 5 minutes.

A force balance system for the measurement of skin friction drag force

NASA Technical Reports Server (NTRS)

Moore, J. W.; Mcvey, E. S.

1971-01-01

Research on force balance instrumentation to measure the skin friction of hypersonic vehicles at extreme temperatures, high altitudes and in a vibration field is discussed. A rough overall summary and operating instructions for the equipment are presented.

An Ultrasound Surface Wave Technique for Assessing Skin and Lung Diseases.

PubMed

Zhang, Xiaoming; Zhou, Boran; Kalra, Sanjay; Bartholmai, Brian; Greenleaf, James; Osborn, Thomas

2018-02-01

Systemic sclerosis (SSc) is a multi-organ connective tissue disease characterized by immune dysregulation and organ fibrosis. Severe organ involvement, especially of the skin and lung, is the cause of morbidity and mortality in SSc. Interstitial lung disease (ILD) includes multiple lung disorders in which the lung tissue is fibrotic and stiffened. The purpose of this study was to translate ultrasound surface wave elastography (USWE) for assessing patients with SSc and/or ILD via measuring surface wave speeds of both skin and superficial lung tissue. Forty-one patients with both SSc and ILD and 30 healthy patients were enrolled in this study. An external harmonic vibration was used to generate the wave propagation on the skin or lung. Three excitation frequencies of 100, 150 and 200 Hz were used. An ultrasound probe was used to measure the wave propagation in the tissue non-invasively. Surface wave speeds were measured on the forearm and upper arm of both left and right arm, as well as the upper and lower lungs, through six intercostal spaces of patients and healthy patients. Viscoelasticity of the skin was calculated by the wave speed dispersion with frequency using the Voigt model. The magnitudes of surface wave speed and viscoelasticity of patients' skin were significantly higher than those of healthy patients (p <0.0001) for each location and each frequency. The surface wave speeds of patients' lung were significantly higher than those of healthy patients (p <0.0001) for each location and each frequency. USWE is a non-invasive and non-ionizing technique for measuring both skin and lung surface wave speed and may be useful for quantitative assessment of SSc and/or ILD. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

On Measuring Quantitative Interpretations of Reasonable Doubt

ERIC Educational Resources Information Center

Dhami, Mandeep K.

2008-01-01

Beyond reasonable doubt represents a probability value that acts as the criterion for conviction in criminal trials. I introduce the membership function (MF) method as a new tool for measuring quantitative interpretations of reasonable doubt. Experiment 1 demonstrated that three different methods (i.e., direct rating, decision theory based, and…

Measuring the penetration of a skin sensitizer and its delivery vehicles simultaneously with confocal Raman spectroscopy.

PubMed

Bonnist, E Y M; Gorce, J-P; Mackay, C; Pendlington, R U; Pudney, P D A

2011-01-01

Among the factors determining the propensity of a chemical to induce skin allergy are the penetration into skin and the kinetics of ingress. Confocal Raman spectroscopy can provide such information as it enables direct, spatially resolved measurement of the skin and of any chemical uptake. Several chemicals can be monitored at once, and the method is non-destructive (light in, light out) so that the skin can be kept intact for repeated and continuous measurement. Raman spectroscopy was used to follow the penetration of 2.5 weight percent trans-cinnamaldehyde and its delivery vehicle into skin in vitro, up to 24 h after topical application. A custom-made Bronaugh-type diffusion cell that was suitable for the Raman experiment was used. Four different vehicles were tested: absolute ethanol, 50% aqueous ethanol, propylene glycol and acetone:olive oil (4:1); these gave different time scales for cinnamaldehyde penetration. The acetone:olive oil vehicle phase-separated on the skin surface and the cinnamaldehyde penetrated at different rates in the different phases, which may be of significance since this is the preferred solvent for the local lymph node assay (an in vivo animal test used to generate hazard information on skin sensitization). In conclusion, the Raman method gives valuable detailed information on chemical ingress, clearly differentiates between different delivery rates and allows solvent monitoring alongside the chemical of interest. Copyright © 2011 S. Karger AG, Basel.

Prediction of Coronal Mass Ejections From Vector Magnetograms: Quantitative Measures as Predictors

NASA Technical Reports Server (NTRS)

Falconer, D. A.; Moore, R. L.; Gary, G. A.; Rose, M. Franklin (Technical Monitor)

2001-01-01

We derived two quantitative measures of an active region's global nonpotentiality from the region's vector magnetogram, 1) the net current (I(sub N)), and 2) the length of strong-shear, strong-field main neutral line (Lss), and used these two measures in a pilot study of the CME productivity of 4 active regions. We compared the global nonpotentiality measures to the active regions' CME productivity determined from GOES and Yohkoh/SXT observations. We found that two of the active regions were highly globally nonpotential and were CME productive, while the other two active regions had little global nonpotentiality and produced no CMEs. At the Fall 2000 AGU, we reported on an expanded study (12 active regions and 17 magnetograms) in which we evaluated four quantitative global measures of an active region's magnetic field and compared these measures with the CME productivity. The four global measures (all derived from MSFC vector magnetograms) included our two previous measures (I(sub N) and L(sub ss)) as well as two new ones, the total magnetic flux (PHI) (a measure of an active region's size), and the normalized twist (alpha (bar)= muIN/PHI). We found that the three quantitative measures of global nonpotentiality (I(sub N), L(sub ss), alpha (bar)) were all well correlated (greater than 99% confidence level) with an active region's CME productivity within plus or minus 2 days of the day of the magnetogram. We will now report on our findings of how good our quantitative measures are as predictors of active-region CME productivity, using only CMEs that occurred after the magnetogram. We report the preliminary skill test of these quantitative measures as predictors. We compare the CME prediction success of our quantitative measures to the CME prediction success based on an active region's past CME productivity. We examine the cases of the handful of false positive and false negatives to look for improvements to our predictors. This work is funded by NSF through the Space

Verification of echo amplitude envelope analysis method in skin tissues for quantitative follow-up of healing ulcers

NASA Astrophysics Data System (ADS)

Omura, Masaaki; Yoshida, Kenji; Akita, Shinsuke; Yamaguchi, Tadashi

2018-07-01

We aim to develop an ultrasonic tissue characterization method for the follow-up of healing ulcers by diagnosing collagen fibers properties. In this paper, we demonstrated a computer simulation with simulation phantoms reflecting irregularly distributed collagen fibers to evaluate the relationship between physical properties, such as number density and periodicity, and the estimated characteristics of the echo amplitude envelope using the homodyned-K distribution. Moreover, the consistency between echo signal characteristics and the structures of ex vivo human tissues was verified from the measured data of normal skin and nonhealed ulcers. In the simulation study, speckle or coherent signal characteristics are identified as periodically or uniformly distributed collagen fibers with high number density and high periodicity. This result shows the effectiveness of the analysis using the homodyned-K distribution for tissues with complicated structures. Normal skin analysis results are characterized as including speckle or low-coherence signal components, and a nonhealed ulcer is different from normal skin with respect to the physical properties of collagen fibers.

Quantitative measurement of hypertrophic scar: interrater reliability and concurrent validity.

PubMed

Nedelec, Bernadette; Correa, José A; Rachelska, Grazyna; Armour, Alexis; LaSalle, Léo

2008-01-01

Research into the pathophysiology and treatment of hypertrophic scar (HSc) remains limited by the heterogeneity of scar and the imprecision with which its severity is measured. The objective of this study was to test the interrater reliability and concurrent validity of the Cutometer measurement of elasticity, the Mexameter measurement of erythema and pigmentation, and total thickness measure of the DermaScan C relative to the modified Vancouver Scar Scale (mVSS) in patient-matched normal skin, normal scar, and HSc. Three independent investigators evaluated 128 sites (severe HSc, moderate or mild HSc, donor site, and normal skin) on 32 burn survivors using all of the above measurement tools. The intraclass correlation coefficient, which was used to measure interrater reliability, reflects the inherent amount of error in the measure and is considered acceptable when it is >0.75. Interrater reliability of the totals of the height, pliability, and vascularity subscales of the mVSS fell below the acceptable limit ( congruent with0.50). The individual subscales of the mVSS fell well below the acceptable level (< or =0.3). The Cutometer reading of elasticity provided acceptable reliability (>0.89) for each study site with the exception of severe scar. Mexameter and DermaScan C reliability measurements were acceptable for all sites (>0.82). Concurrent validity correlations with the mVSS were significant except for the comparison of the mVSS pliability subscale and the Cutometer maximum deformation measure comparison in severe scar. In conclusion, the Mexameter and DermaScan C measurements of scar color and thickness of all sites, as well as the Cutometer measurement of elasticity in all but the most severe scars shows high interrater reliability. Their significant concurrent validity with the mVSS confirms that these tools are measuring the same traits as the mVSS, and in a more objective way.

Use of dew-point detection for quantitative measurement of sweating rate

NASA Technical Reports Server (NTRS)

Brengelmann, G. L.; Mckeag, M.; Rowell, L. B.

1975-01-01

A method of measuring sweat rate (SR) based on detection of dew point (DP) is proposed which has advantages that may be attractive to other laboratories concerned with recording SR from selected areas of skin. It is similar to other methods in that dry gas is passed through a capsule which isolates several square centimeters of skin surface. The difference is in the means of determining how much gaseous water is carried off in the effluent moist gas. The DP detector used is free of the drawbacks of previous devices. DP is obtained through the fundamental technique of determining the temperature at which condensate forms on a mirror. Variations in DP are tracked rapidly, and accurately (+ or - 0.8 C nominal, sensitivity + or - 0.05 C) over a wide range ( -40 C to +50 C) without measurable hysteresis. The detector asembly is rugged and readily opened for cleaning and inspection.

Modeling Electronic Skin Response to Normal Distributed Force

PubMed Central

Seminara, Lucia

2018-01-01

The reference electronic skin is a sensor array based on PVDF (Polyvinylidene fluoride) piezoelectric polymers, coupled to a rigid substrate and covered by an elastomer layer. It is first evaluated how a distributed normal force (Hertzian distribution) is transmitted to an extended PVDF sensor through the elastomer layer. A simplified approach based on Boussinesq’s half-space assumption is used to get a qualitative picture and extensive FEM simulations allow determination of the quantitative response for the actual finite elastomer layer. The ultimate use of the present model is to estimate the electrical sensor output from a measure of a basic mechanical action at the skin surface. However this requires that the PVDF piezoelectric coefficient be known a-priori. This was not the case in the present investigation. However, the numerical model has been used to fit experimental data from a real skin prototype and to estimate the sensor piezoelectric coefficient. It turned out that this value depends on the preload and decreases as a result of PVDF aging and fatigue. This framework contains all the fundamental ingredients of a fully predictive model, suggesting a number of future developments potentially useful for skin design and validation of the fabrication technology. PMID:29401692

Measurement of diffusion coefficient of propylene glycol in skin tissue

NASA Astrophysics Data System (ADS)

Genin, Vadim D.; Bashkatov, Alexey N.; Genina, Elina A.; Tuchin, Valery V.

2015-03-01

Optical clearing of the rat skin under the action of propylene glycol was studied ex vivo. It was found that collimated transmittance of skin samples increased, whereas weight and thickness of the samples decreased during propylene glycol penetration in skin tissue. A mechanism of the optical clearing under the action of propylene glycol is discussed. Diffusion coefficient of propylene glycol in skin tissue ex vivo has been estimated as (1.35±0.95)×10-7 cm2/s with the taking into account of kinetics of both weight and thickness of skin samples. The presented results can be useful for enhancement of many methods of laser therapy and optical diagnostics of skin diseases and localization of subcutaneous neoplasms.

A multivariable model for predicting the frictional behaviour and hydration of the human skin.

PubMed

Veijgen, N K; van der Heide, E; Masen, M A

2013-08-01

The frictional characteristics of skin-object interactions are important when handling objects, in the assessment of perception and comfort of products and materials and in the origins and prevention of skin injuries. In this study, based on statistical methods, a quantitative model is developed that describes the friction behaviour of human skin as a function of the subject characteristics, contact conditions, the properties of the counter material as well as environmental conditions. Although the frictional behaviour of human skin is a multivariable problem, in literature the variables that are associated with skin friction have been studied using univariable methods. In this work, multivariable models for the static and dynamic coefficients of friction as well as for the hydration of the skin are presented. A total of 634 skin-friction measurements were performed using a recently developed tribometer. Using a statistical analysis, previously defined potential influential variables were linked to the static and dynamic coefficient of friction and to the hydration of the skin, resulting in three predictive quantitative models that descibe the friction behaviour and the hydration of human skin respectively. Increased dynamic coefficients of friction were obtained from older subjects, on the index finger, with materials with a higher surface energy at higher room temperatures, whereas lower dynamic coefficients of friction were obtained at lower skin temperatures, on the temple with rougher contact materials. The static coefficient of friction increased with higher skin hydration, increasing age, on the index finger, with materials with a higher surface energy and at higher ambient temperatures. The hydration of the skin was associated with the skin temperature, anatomical location, presence of hair on the skin and the relative air humidity. Predictive models have been derived for the static and dynamic coefficient of friction using a multivariable approach. These

Considerations for the measurement of core, skin and mean body temperatures.

PubMed

Taylor, Nigel A S; Tipton, Michael J; Kenny, Glen P

2014-12-01

Despite previous reviews and commentaries, significant misconceptions remain concerning deep-body (core) and skin temperature measurement in humans. Therefore, the authors have assembled the pertinent Laws of Thermodynamics and other first principles that govern physical and physiological heat exchanges. The resulting review is aimed at providing theoretical and empirical justifications for collecting and interpreting these data. The primary emphasis is upon deep-body temperatures, with discussions of intramuscular, subcutaneous, transcutaneous and skin temperatures included. These are all turnover indices resulting from variations in local metabolism, tissue conduction and blood flow. Consequently, inter-site differences and similarities may have no mechanistic relationship unless those sites have similar metabolic rates, are in close proximity and are perfused by the same blood vessels. Therefore, it is proposed that a gold standard deep-body temperature does not exist. Instead, the validity of each measurement must be evaluated relative to one's research objectives, whilst satisfying equilibration and positioning requirements. When using thermometric computations of heat storage, the establishment of steady-state conditions is essential, but for clinically relevant states, targeted temperature monitoring becomes paramount. However, when investigating temperature regulation, the response characteristics of each temperature measurement must match the forcing function applied during experimentation. Thus, during dynamic phases, deep-body temperatures must be measured from sites that track temperature changes in the central blood volume. Copyright © 2014 Elsevier Ltd. All rights reserved.

Measuring Skin Temperatures with the IASI Hyperspectral Mission

NASA Astrophysics Data System (ADS)

Safieddine, S.; George, M.; Clarisse, L.; Clerbaux, C.

2017-12-01

Although the role of satellites in observing the variability of the Earth system has increased in recent decades, remote-sensing observations are still underexploited to accurately assess climate change fingerprints, in particular temperature variations. The IASI - Flux and Temperature (IASI-FT) project aims at providing new benchmarks for temperature observations using the calibrated radiances measured twice a day at any location by the IASI thermal infrared instrument on the suite of MetOp satellites (2006-2025). The main challenge is to achieve the accuracy and stability needed for climate studies, particularly that required for climate trends. Time series for land and sea skin surface temperatures are derived and compared with in situ measurements and atmospheric reanalysis. The observed trends are analyzed at seasonal and regional scales in order to disentangle natural (weather/dynamical) variability and human-induced climate forcings.

Predicting chemically-induced skin reactions. Part II: QSAR models of skin permeability and the relationships between skin permeability and skin sensitization

PubMed Central

Alves, Vinicius M.; Muratov, Eugene; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Andrade, Carolina H.; Tropsha, Alexander

2015-01-01

Skin permeability is widely considered to be mechanistically implicated in chemically-induced skin sensitization. Although many chemicals have been identified as skin sensitizers, there have been very few reports analyzing the relationships between molecular structure and skin permeability of sensitizers and non-sensitizers. The goals of this study were to: (i) compile, curate, and integrate the largest publicly available dataset of chemicals studied for their skin permeability; (ii) develop and rigorously validate QSAR models to predict skin permeability; and (iii) explore the complex relationships between skin sensitization and skin permeability. Based on the largest publicly available dataset compiled in this study, we found no overall correlation between skin permeability and skin sensitization. In addition, cross-species correlation coefficient between human and rodent permeability data was found to be as low as R2=0.44. Human skin permeability models based on the random forest method have been developed and validated using OECD-compliant QSAR modeling workflow. Their external accuracy was high (Q2ext = 0.73 for 63% of external compounds inside the applicability domain). The extended analysis using both experimentally-measured and QSAR-imputed data still confirmed the absence of any overall concordance between skin permeability and skin sensitization. This observation suggests that chemical modifications that affect skin permeability should not be presumed a priori to modulate the sensitization potential of chemicals. The models reported herein as well as those developed in the companion paper on skin sensitization suggest that it may be possible to rationally design compounds with the desired high skin permeability but low sensitization potential. PMID:25560673

Predicting chemically-induced skin reactions. Part II: QSAR models of skin permeability and the relationships between skin permeability and skin sensitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alves, Vinicius M.; Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599; Muratov, Eugene

Skin permeability is widely considered to be mechanistically implicated in chemically-induced skin sensitization. Although many chemicals have been identified as skin sensitizers, there have been very few reports analyzing the relationships between molecular structure and skin permeability of sensitizers and non-sensitizers. The goals of this study were to: (i) compile, curate, and integrate the largest publicly available dataset of chemicals studied for their skin permeability; (ii) develop and rigorously validate QSAR models to predict skin permeability; and (iii) explore the complex relationships between skin sensitization and skin permeability. Based on the largest publicly available dataset compiled in this study, wemore » found no overall correlation between skin permeability and skin sensitization. In addition, cross-species correlation coefficient between human and rodent permeability data was found to be as low as R{sup 2} = 0.44. Human skin permeability models based on the random forest method have been developed and validated using OECD-compliant QSAR modeling workflow. Their external accuracy was high (Q{sup 2}{sub ext} = 0.73 for 63% of external compounds inside the applicability domain). The extended analysis using both experimentally-measured and QSAR-imputed data still confirmed the absence of any overall concordance between skin permeability and skin sensitization. This observation suggests that chemical modifications that affect skin permeability should not be presumed a priori to modulate the sensitization potential of chemicals. The models reported herein as well as those developed in the companion paper on skin sensitization suggest that it may be possible to rationally design compounds with the desired high skin permeability but low sensitization potential. - Highlights: • It was compiled the largest publicly-available skin permeability dataset. • Predictive QSAR models were developed for skin permeability. • No concordance between

Quantitative color measurement for black walnut wood.

Treesearch

Ali A. Moslemi

1967-01-01

Black walnut (Juglans nigra L.) veneer specimens with wide variations in color were evaluated by a quantitative method of color measurement. The internationally adopted CIE system of colorimetry was used to analyze the data. These data were converted to also show them in the Munsell system. Color differences among the walnut veneer specimens were also numerically...

Correlation between skin color evaluation by skin color scale chart and narrowband reflectance spectrophotometer.

PubMed

Treesirichod, Arucha; Chansakulporn, Somboon; Wattanapan, Pattra

2014-07-01

Various methods are available for the evaluation of skin color. A skin color scale chart is a convenient and inexpensive tool. However, the correlation between a skin color scale chart and objective measurement has not been evaluated. To assess the correlation between skin color evaluation done by a skin color scale chart (Felix von Luschan skin color chart) and a narrowband reflectance spectrophotometer (Mexameter MX18). The participants were evaluated for skin color by using the Felix von Luschan skin color chart (range 1-36) and a narrowband reflectance spectrophotometer (Mexameter MX18) in which the results of the measurements were expressed as Erythema (E) and Melanin (M) indices. Skin color was measured on four different anatomical skin sites from each participant on the medial aspect of the volar and the dorsal regions of both forearms. A total of 208 records from 52 participants were established. The majority of participants (19.2%) were rated with the skin color scale at the number 16 (range 14-33). The mean M plus E, M, and E indices were 498.9 ± 143.9, 230.4 ± 74.4, and 268.5 ± 73.2, respectively. The correlation coefficient between the number on the skin color scale and each index: M plus E, M, and E indices were 0.90, 0.90, and 0.86, respectively, with a statistical significance of P < 0.001. Skin color evaluation using a skin color scale chart has shown a high correlation with skin color evaluation done by the narrowband reflectance spectrophotometer.

Use of Munsell color charts to measure skin tone objectively in nursing home residents at risk for pressure ulcer development.

PubMed

McCreath, Heather E; Bates-Jensen, Barbara M; Nakagami, Gojiro; Patlan, Anabel; Booth, Howard; Connolly, Dana; Truong, Cyndi; Woldai, Agazi

2016-09-01

To assess the feasibility of classifying skin tone using Munsell color chart values and to compare Munsell-based skin tone categories to ethnicity/race to predict pressure ulcer risk. Pressure ulcer classification uses level of visible tissue damage, including skin discoloration over bony prominences. Prevention begins with early detection of damage. Skin discoloration in those with dark skin tones can be difficult to observe, hindering early detection. Observational cohort of 417 nursing home residents from 19 nursing homes collected between 2009-2014, with weekly skin assessments for up to 16 weeks. Assessment included forearm and buttocks skin tone based on Munsell values (Dark, Medium, Light) at three time points, ethnicity/race medical record documentation, and weekly skin assessment on trunk and heels. Inter-rater reliability was high for forearm and buttock values and skin tone. Mean Munsell buttocks values differed significantly by ethnicity/race. Across ethnicity/race, Munsell value ranges overlapped, with the greatest range among African Americans. Trunk pressure ulcer incidence varied by skin tone, regardless of ethnicity/race. In multinomial regression, skin tone was more predictive of skin damage than ethnicity/race for trunk locations but ethnicity/race was more predictive for heels. Given the overlap of Munsell values across ethnicity/race, color charts provide more objective measurement of skin tone than demographic categories. An objective measure of skin tone can improve pressure ulcer risk assessment among patients for whom current clinical guidelines are less effective. © 2016 John Wiley & Sons Ltd.

Model-based approach for quantitative estimates of skin, heart, and lung toxicity risk for left-side photon and proton irradiation after breast-conserving surgery.

PubMed

Tommasino, Francesco; Durante, Marco; D'Avino, Vittoria; Liuzzi, Raffaele; Conson, Manuel; Farace, Paolo; Palma, Giuseppe; Schwarz, Marco; Cella, Laura; Pacelli, Roberto

2017-05-01

Proton beam therapy represents a promising modality for left-side breast cancer (BC) treatment, but concerns have been raised about skin toxicity and poor cosmesis. The aim of this study is to apply skin normal tissue complication probability (NTCP) model for intensity modulated proton therapy (IMPT) optimization in left-side BC. Ten left-side BC patients undergoing photon irradiation after breast-conserving surgery were randomly selected from our clinical database. Intensity modulated photon (IMRT) and IMPT plans were calculated with iso-tumor-coverage criteria and according to RTOG 1005 guidelines. Proton plans were computed with and without skin optimization. Published NTCP models were employed to estimate the risk of different toxicity endpoints for skin, lung, heart and its substructures. Acute skin NTCP evaluation suggests a lower toxicity level with IMPT compared to IMRT when the skin is included in proton optimization strategy (0.1% versus 1.7%, p < 0.001). Dosimetric results show that, with the same level of tumor coverage, IMPT attains significant heart and lung dose sparing compared with IMRT. By NTCP model-based analysis, an overall reduction in the cardiopulmonary toxicity risk prediction can be observed for all IMPT compared to IMRT plans: the relative risk reduction from protons varies between 0.1 and 0.7 depending on the considered toxicity endpoint. Our analysis suggests that IMPT might be safely applied without increasing the risk of severe acute radiation induced skin toxicity. The quantitative risk estimates also support the potential clinical benefits of IMPT for left-side BC irradiation due to lower risk of cardiac and pulmonary morbidity. The applied approach might be relevant on the long term for the setup of cost-effectiveness evaluation strategies based on NTCP predictions.

SERS quantitative urine creatinine measurement of human subject

NASA Astrophysics Data System (ADS)

Wang, Tsuei Lian; Chiang, Hui-hua K.; Lu, Hui-hsin; Hung, Yung-da

2005-03-01

SERS method for biomolecular analysis has several potentials and advantages over traditional biochemical approaches, including less specimen contact, non-destructive to specimen, and multiple components analysis. Urine is an easily available body fluid for monitoring the metabolites and renal function of human body. We developed surface-enhanced Raman scattering (SERS) technique using 50nm size gold colloidal particles for quantitative human urine creatinine measurements. This paper shows that SERS shifts of creatinine (104mg/dl) in artificial urine is from 1400cm-1 to 1500cm-1 which was analyzed for quantitative creatinine measurement. Ten human urine samples were obtained from ten healthy persons and analyzed by the SERS technique. Partial least square cross-validation (PLSCV) method was utilized to obtain the estimated creatinine concentration in clinically relevant (55.9mg/dl to 208mg/dl) concentration range. The root-mean square error of cross validation (RMSECV) is 26.1mg/dl. This research demonstrates the feasibility of using SERS for human subject urine creatinine detection, and establishes the SERS platform technique for bodily fluids measurement.

Mathematical modeling and fluorescence imaging to study the Ca2+ turnover in skinned muscle fibers.

PubMed Central

Uttenweiler, D; Weber, C; Fink, R H

1998-01-01

A mathematical model was developed for the simulation of the spatial and temporal time course of Ca2+ ion movement in caffeine-induced calcium transients of chemically skinned muscle fiber preparations. Our model assumes cylindrical symmetry and quantifies the radial profile of Ca2+ ion concentration by solving the diffusion equations for Ca2+ ions and various mobile buffers, and the rate equations for Ca2+ buffering (mobile and immobile buffers) and for the release and reuptake of Ca2+ ions by the sarcoplasmic reticulum (SR), with a finite-difference algorithm. The results of the model are compared with caffeine-induced spatial Ca2+ transients obtained from saponin skinned murine fast-twitch fibers by fluorescence photometry and imaging measurements using the ratiometric dye Fura-2. The combination of mathematical modeling and digital image analysis provides a tool for the quantitative description of the total Ca2+ turnover and the different contributions of all interacting processes to the overall Ca2+ transient in skinned muscle fibers. It should thereby strongly improve the usage of skinned fibers as quantitative assay systems for many parameters of the SR and the contractile apparatus helping also to bridge the gap to the intact muscle fiber. PMID:9545029

Noninvasive detection of skin cancers by measuring optical properties of tissues

NASA Astrophysics Data System (ADS)

Wang, Lihong V.; Jacques, Steven L.

1995-05-01

Skin cancer is the most frequently occurring cancer of all cancers. Each yea rover 500,000 new cases of skin cancer will be detected. A high percentage of skin cancers are diseases in which fatalities can be all but eliminated and morbidity reduced if detected early and treated properly. These skin lesions are distinguished generally by subjective visual inspection and their definitive diagnosis requires time-consuming expensive histopathological evaluation of excisional or incisional biopsies. In vivo experimental evidence published in the literature has shown that cancerous skin lesions have different total diffuse reflectance spectra than non- cancerous lesions or normal skin. Therefore, cancerous skin lesions may be differentiated from non-cancerous skin lesions by comparing the optical properties of the skin lesions with those of the surrounding normal skin sites, where the optical properties of the normal skin sites are used to account for different types of skin or different areas of skin. We have demonstrated that the effect of melanin concentration on the diffuse reflectance may be removed by extrapolating the reflectance at different wavelengths to an apparent pivot point. Because the concentration of melanin does not indicate malignancy, the removal of its effect is important to avoid false detection. The total diffuse reflectance depends on the albedo and anisotropy of tissues. Therefore, the total diffuse reflectance will remain the same as long as the anisotropy and the ratio between the absorption coefficient and the reduced scattering coefficient remain the same. Separating the absorption and scattering effects should enhance the detection sensitivity of skin cancers.

Design, fabrication and experimental validation of a novel dry-contact sensor for measuring electroencephalography signals without skin preparation.

PubMed

Liao, Lun-De; Wang, I-Jan; Chen, Sheng-Fu; Chang, Jyh-Yeong; Lin, Chin-Teng

2011-01-01

In the present study, novel dry-contact sensors for measuring electro-encephalography (EEG) signals without any skin preparation are designed, fabricated by an injection molding manufacturing process and experimentally validated. Conventional wet electrodes are commonly used to measure EEG signals; they provide excellent EEG signals subject to proper skin preparation and conductive gel application. However, a series of skin preparation procedures for applying the wet electrodes is always required and usually creates trouble for users. To overcome these drawbacks, novel dry-contact EEG sensors were proposed for potential operation in the presence or absence of hair and without any skin preparation or conductive gel usage. The dry EEG sensors were designed to contact the scalp surface with 17 spring contact probes. Each probe was designed to include a probe head, plunger, spring, and barrel. The 17 probes were inserted into a flexible substrate using a one-time forming process via an established injection molding procedure. With these 17 spring contact probes, the flexible substrate allows for high geometric conformity between the sensor and the irregular scalp surface to maintain low skin-sensor interface impedance. Additionally, the flexible substrate also initiates a sensor buffer effect, eliminating pain when force is applied. The proposed dry EEG sensor was reliable in measuring EEG signals without any skin preparation or conductive gel usage, as compared with the conventional wet electrodes.

Design, Fabrication and Experimental Validation of a Novel Dry-Contact Sensor for Measuring Electroencephalography Signals without Skin Preparation

PubMed Central

Liao, Lun-De; Wang, I-Jan; Chen, Sheng-Fu; Chang, Jyh-Yeong; Lin, Chin-Teng

2011-01-01

In the present study, novel dry-contact sensors for measuring electro-encephalography (EEG) signals without any skin preparation are designed, fabricated by an injection molding manufacturing process and experimentally validated. Conventional wet electrodes are commonly used to measure EEG signals; they provide excellent EEG signals subject to proper skin preparation and conductive gel application. However, a series of skin preparation procedures for applying the wet electrodes is always required and usually creates trouble for users. To overcome these drawbacks, novel dry-contact EEG sensors were proposed for potential operation in the presence or absence of hair and without any skin preparation or conductive gel usage. The dry EEG sensors were designed to contact the scalp surface with 17 spring contact probes. Each probe was designed to include a probe head, plunger, spring, and barrel. The 17 probes were inserted into a flexible substrate using a one-time forming process via an established injection molding procedure. With these 17 spring contact probes, the flexible substrate allows for high geometric conformity between the sensor and the irregular scalp surface to maintain low skin-sensor interface impedance. Additionally, the flexible substrate also initiates a sensor buffer effect, eliminating pain when force is applied. The proposed dry EEG sensor was reliable in measuring EEG signals without any skin preparation or conductive gel usage, as compared with the conventional wet electrodes. PMID:22163929

Development of optical near-infrared spectroscopy instruments for human skin sebum measurement

NASA Astrophysics Data System (ADS)

Msabbri, A. R.; Mohamad, M.; MatJafri, M. Z.; Omar, A. F.

2014-05-01

There are many techniques and instruments that are currently available to give better results for measuring the quality of human skin. In this study, two non-invasive spectroscopy instruments have been used namely NIRQuest spectrometer and ASD FieldSpec® 3 Spectroradiometer. Both of these spectroscopy instruments were used to find the correlation technique with the commercial instruments (DermaLab® USB Sebum Module). Initially an experiment was conducted to find intensities peak of the absorption of oleic acid as a part of sebum composition. From the spectra peak of the absorbance, the wavelength will be determined. Next step was to measure the reflectance of human skin sebum by using two spectroscopic instruments. The analysis will carry on at the wavelength that have been chosen from the previous study and also from the wavelength of the fatty acid to find the best wavelength that contribute in sebum composition. From several analyses, the wavelengths that contribute in sebum were 1208, 1414, 1726, and 1758 nm that obtained the value of R2 0.8444 for NIRQuest Spectrometer and 0.8532 for ASD FieldSpec® 3 Spectroradiometer. For future research this non- invasive techniques can be used in dermatology field for the use of various skin analysis. Besides that, the less wavelength used is an advantage to develop instruments with less amount of wavelength sensor. It can reduce the cost of development.

Skin-interfaced systems for sweat collection and analytics

PubMed Central

Choi, Jungil; Ghaffari, Roozbeh; Baker, Lindsay B.; Rogers, John A.

2018-01-01

Recent interdisciplinary advances in materials, mechanics, and microsystem designs for biocompatible electronics, soft microfluidics, and electrochemical biosensors establish the foundations for emerging classes of thin, skin-interfaced platforms capable of capturing, storing, and performing quantitative, spatiotemporal measurements of sweat chemistry, instantaneous local sweat rate, and total sweat loss. This review summarizes scientific and technical progress in this area and highlights the implications in real time and ambulatory modes of deployment during physical activities across a broad range of contexts in clinical health, physiology research, fitness/wellness, and athletic performance. PMID:29487915

Construction, in vitro and in vivo evaluation of an in-house conductance meter for measurement of skin hydration.

PubMed

Hamed, Saja H; Altrabsheh, Bilal; Assa'd, Tareq; Jaradat, Said; Alshra'ah, Mohammad; Aljamal, Abdulfattah; Alkhatib, Hatim S; Almalty, Abdul-Majeed

2012-12-01

Different probes are used in dermato-cosmetic research to measure the electrical properties of the skin. The principle governing the choice of the geometry and material of the measuring probe is not well defined in the literature and some device's measuring principles are not accessible for the scientific community. The purpose of this work was to develop a simple inexpensive conductance meter for the objective in vivo evaluation of skin hydration. The conductance meter probe was designed using the basic equation governing wave propagation along Transverse Electromagnetic transmission lines. It consisted of two concentric copper circular electrodes printed on FR4 dielectric material. The performance of the probe was validated by evaluating its measurement depth, its ability to monitor in vitro water sorption-desorption and in vivo skin hydration effect in comparison to that of the Corneometer CM 825. The measurement depth of the probe, 15 μm, was comparable to that of CM 825. The in vitro readings of the probe correlated strongly with the amount of water adsorbed on filter paper. Skin hydration after application of a moisturizer was monitored effectively by the new probe with good correlation to the results of CM 825. In conclusion, a simple probe for evaluating skin hydration was made from off-the-shelf materials and its performance was validated in comparison to a commercially available probe. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

Skin-to-skin contact by fathers and the impact on infant and paternal outcomes: an integrative review.

PubMed

Shorey, Shefaly; He, Hong-Gu; Morelius, Evalotte

2016-09-01

to summarise research evidence on the impact of father-infant skin-to-skin contact on infant and paternal outcomes. an integrative literature review. PubMed, ScienceDirect, PsycINFO, and Cumulative Index to Nursing & Allied Health. studies included were: (1) published in English between January 1995 to September 2015; (2) primary researches; and (3) focused on fathers providing skin-to-skin contact with their infants and its impact on infant and paternal outcomes. The Joanna Briggs Institute's Critical Appraisal Checklists were used to appraise the scientific rigour of the studies. twelve studies (10 quantitative and two qualitative) were included in this review. Father-infant skin-to-skin contact had positive impacts on infants' outcomes, including temperature and pain, bio-physiological markers, behavioural response, as well as paternal outcomes, which include parental role attainment, paternal interaction behaviour, and paternal stress and anxiety. a father's involvement in providing skin-to-skin contact seems to be feasible and beneficial to both infants and fathers. However, there has been a scarcity of literature that exclusively examines fathers' involvement and perceptions related to skin-to-skin contact in the postpartum period. Future research should examine skin-to-skin contact by fathers and its associated benefits, as well as fathers' perceptions on father-infant SSC among varied populations. a father's involvement in providing skin-to-skin contact should be promoted during the postnatal period. Father-infant skin-to-skin contact is a valuable alternative, especially during the unavailability of mothers due to special circumstances, including medical emergencies and caesarean section. Copyright © 2016 Elsevier Ltd. All rights reserved.

Error analysis on spinal motion measurement using skin mounted sensors.

PubMed

Yang, Zhengyi; Ma, Heather Ting; Wang, Deming; Lee, Raymond

2008-01-01

Measurement errors of skin-mounted sensors in measuring forward bending movement of the lumbar spines are investigated. In this investigation, radiographic images capturing the entire lumbar spines' positions were acquired and used as a 'gold' standard. Seventeen young male volunteers (21 (SD 1) years old) agreed to participate in the study. Light-weight miniature sensors of the electromagnetic tracking systems-Fastrak were attached to the skin overlying the spinous processes of the lumbar spine. With the sensors attached, the subjects were requested to take lateral radiographs in two postures: neutral upright and full flexion. The ranges of motions of lumbar spine were calculated from two sets of digitized data: the bony markers of vertebral bodies and the sensors and compared. The differences between the two sets of results were then analyzed. The relative movement between sensor and vertebrae was decomposed into sensor sliding and titling, from which sliding error and titling error were introduced. Gross motion range of forward bending of lumbar spine measured from bony markers of vertebrae is 67.8 degrees (SD 10.6 degrees ) and that from sensors is 62.8 degrees (SD 12.8 degrees ). The error and absolute error for gross motion range were 5.0 degrees (SD 7.2 degrees ) and 7.7 degrees (SD 3.9 degrees ). The contributions of sensors placed on S1 and L1 to the absolute error were 3.9 degrees (SD 2.9 degrees ) and 4.4 degrees (SD 2.8 degrees ), respectively.

Predicting skin deficits through surface area measurements in ear reconstruction and adult ear surface area norms.

PubMed

Yazar, Memet; Sevim, Kamuran Zeynep; Irmak, Fatih; Yazar, Sevgi Kurt; Yeşilada, Ayşin Karasoy; Karşidağğ, Semra Hacikerim; Tatlidede, Hamit Soner

2013-07-01

Ear reconstruction is one of the most challenging procedures in plastic surgery practice. Many studies and techniques have been described in the literature for carving a well-pronounced framework. However, just as important as the cartilage framework is the ample amount of delicate skin coverage of the framework. In this report, we introduce an innovative method of measuring the skin surface area of the auricle from a three-dimensional template created from the healthy ear.The study group consisted of 60 adult Turkish individuals who were randomly selected (30 men and 30 women). The participant ages ranged from 18 to 45 years (mean, 31.5 years), and they had no history of trauma or congenital anomalies. The template is created by dividing the ear into aesthetic subunits and using ImageJ software to estimate the necessary amount of total skin surface area required.Reconstruction of the auricle is a complicated process that requires experience and patience to provide the auricular details. We believe this estimate will shorten the learning curve for residents and surgeons interested in ear reconstruction and will help surgeons obtain adequate skin to drape over the well-sculpted cartilage frameworks by providing a reference list of total ear skin surface area measurements for Turkish men and women.

Quantitative Measurement of Trans-Fats by Infrared Spectroscopy

ERIC Educational Resources Information Center

Walker, Edward B.; Davies, Don R.; Campbell, Mike

2007-01-01

Trans-fat is a general term, which is mainly used to describe the various trans geometric isomers present in unsaturated fatty acids. Various techniques are now used for a quantitative measurement of the amount of trans-fats present in foods and cooking oil.

Effect of perspiration on skin temperature measurements by infrared thermography and contact thermometry during aerobic cycling

NASA Astrophysics Data System (ADS)

Priego Quesada, Jose Ignacio; Martínez Guillamón, Natividad; Cibrián Ortiz de Anda, Rosa M.^a.; Psikuta, Agnes; Annaheim, Simon; Rossi, René Michel; Corberán Salvador, José Miguel; Pérez-Soriano, Pedro; Salvador Palmer, Rosario

2015-09-01

The aim of the present study was to compare infrared thermography and thermal contact sensors for measuring skin temperature during cycling in a moderate environment. Fourteen cyclists performed a 45-min cycling test at 50% of peak power output. Skin temperatures were simultaneously recorded by infrared thermography and thermal contact sensors before and immediately after cycling activity as well as after 10 min cooling-down, representing different skin wetness and blood perfusion states. Additionally, surface temperature during well controlled dry and wet heat exchange (avoiding thermoregulatory responses) using a hot plate system was assessed by infrared thermography and thermal contact sensors. In human trials, the inter-method correlation coefficient was high when measured before cycling (r = 0.92) whereas it was reduced immediately after the cycling (r = 0.82) and after the cooling-down phase (r = 0.59). Immediately after cycling, infrared thermography provided lower temperature values than thermal contact sensors whereas it presented higher temperatures after the cooling-down phase. Comparable results as in human trials were observed for hot plate tests in dry and wet states. Results support the application of infrared thermography for measuring skin temperature in exercise scenarios where perspiration does not form a water film.

Near-infrared optical properties of ex-vivo human skin and subcutaneous tissues using reflectance and transmittance measurements

NASA Astrophysics Data System (ADS)

Simpson, Rebecca; Laufer, Jan G.; Kohl-Bareis, Matthias; Essenpreis, Matthias; Cope, Mark

1997-08-01

The vast majority of 'non-invasive' measurements of human tissues using near infrared spectroscopy rely on passing light through the dermis and subdermis of the skin. Accurate knowledge of the optical properties of these tissues is essential to put into models of light transport and predict the effects of skin perfusion on measurements of deep tissue. Additionally, the skin could be a useful accessible organ for non-invasively determining the constituents of blood flowing through it. Samples of abdominal human skin (including subdermal tissue) were obtained from either post mortem examinations or plastic surgery. The samples were separated into a dermal layer (epidermis and dermis, 1.5 to 2 mm tick), and a sub-cutaneous layer comprised largely of fat. They were enclosed between two glass coverslips and placed in an integrating sphere to measure their reflectance and transmittance over a range of wavelengths from 600 to 1000 nm. The reflectance and transmittance values were converted into average absorption and reduced scattering coefficients by comparison with a Monte Carlo model of light transport. Improvements to the Monte Carlo model and measurement technique removed some previous uncertainties. The results show excellent separation of reduced scattering and absorption coefficient, with clear absorption peaks of hemoglobin, water and lipid. The effect of tissue storage upon measured optical properties was investigated.

Measurement of transepidermal water loss (TEWL) in cats with experimental skin barrier dysfunction using a closed chamber system.

PubMed

Momota, Yutaka; Shimada, Kenichiro; Gin, Azusa; Matsubara, Takako; Azakami, Daigo; Ishioka, Katsumi; Nakamura, Yuka; Sako, Toshinori

2016-10-01

A closed chamber evaporimeter is suitable for measuring transepidermal water loss (TEWL) in cats because of the compact device size, tolerance to sudden movement and short measuring time. TEWL is a representative parameter for skin barrier dysfunction, which is one of the clinical signs of atopic dermatitis in humans and dogs. Measurement of feline TEWL has been reported, but applicability of this parameter has not been validated. The aims of this study were to determine if tape stripping is a valid experimental model in cats for studying TEWL and to determine if a closed chambered system is a suitable measurement tool for cats. Ten clinically normal cats. In order to evaluate variation of the measured values, TEWL was measured at the right and left side of the three clipped regions (axillae, lateral thigh and groin). Subsequently, TEWL was measured using sequential tape stripping of the stratum corneum as a model of acute barrier disruption. The variations between both sides of the three regions showed no significant difference. Sequential tape stripping was associated with increasing values for TEWL. Feline TEWL was shown to reflect changes in the skin barrier in an experimental model using a closed chamber system and has the potential for evaluating skin barrier function in cats with skin diseases. © 2016 ESVD and ACVD.

Influence of probe pressure on diffuse reflectance spectra of human skin measured in vivo

NASA Astrophysics Data System (ADS)

Popov, Alexey P.; Bykov, Alexander V.; Meglinski, Igor V.

2017-11-01

Mechanical pressure superficially applied on the human skin surface by a fiber-optic probe influences the spatial distribution of blood within the cutaneous tissues. Upon gradual load of weight on the probe, a stepwise increase in the skin reflectance spectra is observed. The decrease in the load follows the similar inverse staircase-like tendency. The observed stepwise reflectance spectra changes are due to, respectively, sequential extrusion of blood from the topical cutaneous vascular beds and their filling afterward. The obtained results are confirmed by Monte Carlo modeling. This implies that pressure-induced influence during the human skin diffuse reflectance spectra measurements in vivo should be taken into consideration, in particular, in the rapidly developing area of wearable gadgets for real-time monitoring of various human body parameters.

Correlation Between Skin Color Evaluation by Skin Color Scale Chart and Narrowband Reflectance Spectrophotometer

PubMed Central

Treesirichod, Arucha; Chansakulporn, Somboon; Wattanapan, Pattra

2014-01-01

Context: Various methods are available for the evaluation of skin color. A skin color scale chart is a convenient and inexpensive tool. However, the correlation between a skin color scale chart and objective measurement has not been evaluated. Aims: To assess the correlation between skin color evaluation done by a skin color scale chart (Felix von Luschan skin color chart) and a narrowband reflectance spectrophotometer (Mexameter MX18). Materials and Methods: The participants were evaluated for skin color by using the Felix von Luschan skin color chart (range 1-36) and a narrowband reflectance spectrophotometer (Mexameter MX18) in which the results of the measurements were expressed as Erythema (E) and Melanin (M) indices. Skin color was measured on four different anatomical skin sites from each participant on the medial aspect of the volar and the dorsal regions of both forearms. Results: A total of 208 records from 52 participants were established. The majority of participants (19.2%) were rated with the skin color scale at the number 16 (range 14-33). The mean M plus E, M, and E indices were 498.9 ± 143.9, 230.4 ± 74.4, and 268.5 ± 73.2, respectively. The correlation coefficient between the number on the skin color scale and each index: M plus E, M, and E indices were 0.90, 0.90, and 0.86, respectively, with a statistical significance of P < 0.001. Conclusions: Skin color evaluation using a skin color scale chart has shown a high correlation with skin color evaluation done by the narrowband reflectance spectrophotometer. PMID:25071249

Measurement and comparison of skin dose using OneDose MOSFET and Mobile MOSFET for patients with acute lymphoblastic leukemia.

PubMed

Mattar, Essam H; Hammad, Lina F; Al-Mohammed, Huda I

2011-07-01

Total body irradiation is a protocol used to treat acute lymphoblastic leukemia in patients prior to bone marrow transplant. It is involved in the treatment of the whole body using a large radiation field with extended source-skin distance. Therefore measuring and monitoring the skin dose during the treatment is important. Two kinds of metal oxide semiconductor field effect transistor (OneDose MOSFET and mobile MOSEFT) dosimeter are used during the treatment delivery to measure the skin dose to specific points and compare it with the target prescribed dose. The objective of this study was to compare the variation of skin dose in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using OneDose MOSFET detectors and Mobile MOSFET, and then compare both results with the target prescribed dose. The measurements involved 32 patient's (16 males, 16 females), aged between 14-30 years, with an average age of 22.41 years. One-Dose MOSFET and Mobile MOSFET dosimetry were performed at 10 different anatomical sites on every patient. The results showed there was no variation between skin dose measured with OneDose MOSFET and Mobile MOSFET in all patients. Furthermore, the results showed for every anatomical site selected there was no significant difference in the dose delivered using either OneDose MOSFET detector or Mobile MOSFET as compared to the prescribed dose. The study concludes that One-Dose MOSFET detectors and Mobile MOSFET both give a direct read-out immediately after the treatment; therefore both detectors are suitable options when measuring skin dose for total body irradiation treatment.

In vivo classification of human skin burns using machine learning and quantitative features captured by optical coherence tomography

NASA Astrophysics Data System (ADS)

Singla, Neeru; Srivastava, Vishal; Singh Mehta, Dalip

2018-02-01

We report the first fully automated detection of human skin burn injuries in vivo, with the goal of automatic surgical margin assessment based on optical coherence tomography (OCT) images. Our proposed automated procedure entails building a machine-learning-based classifier by extracting quantitative features from normal and burn tissue images recorded by OCT. In this study, 56 samples (28 normal, 28 burned) were imaged by OCT and eight features were extracted. A linear model classifier was trained using 34 samples and 22 samples were used to test the model. Sensitivity of 91.6% and specificity of 90% were obtained. Our results demonstrate the capability of a computer-aided technique for accurately and automatically identifying burn tissue resection margins during surgical treatment.

The transfer of technology to measure skin burn depth in humans

NASA Technical Reports Server (NTRS)

Yost, William T.; Cantrell, John H.

1991-01-01

Discussed here is the use of ultrasonic techniques originally used to locate cracks in metal structues to measure burn wound depth in humans. Acoustic impedance, performance tests, and the theoretical model are discussed. Measurements of skin burns on anesthetized pigs made with the the ultrasonic instrumentation were in agreement with diagnoses made by a physician, and subsequently confirmed by the healing process. Researchers felt that the concept proved useful in a clinical setting and that the instrument and concept were ready to extend to the manufacturer.

High-resolution compact shear stress sensor for direct measurement of skin friction in fluid flow

NASA Astrophysics Data System (ADS)

Xu, Muchen; Kim, Chang-Jin ``Cj''

2015-11-01

The high-resolution measurement of skin friction in complex flows has long been of great interest but also a challenge in fluid mechanics. Compared with indirect measurement methods (e.g., laser Doppler velocimetry), direct measurement methods (e.g., floating element) do not involve any analogy and assumption but tend to suffer from instrumentation challenges, such as low sensing resolution or misalignments. Recently, silicon micromachined floating plates showed good resolution and perfect alignment but were too small for general purposes and too fragile to attach other surface samples repeatedly. In this work, we report a skin friction sensor consisting of a monolithic floating plate and a high-resolution optical encoder to measure its displacement. The key for the high resolution is in the suspension beams, which are very narrow (e.g., 0.25 mm) to sense small frictions along the flow direction but thick (e.g., 5 mm) to be robust along all other directions. This compact, low profile, and complete sensor is easy to use and allows repeated attachment and detachment of surface samples. The sheer-stress sensor has been tested in water tunnel and towing tank at different flow conditions, showing high sensing resolution for skin friction measurement. Supported by National Science Foundation (NSF) (No. 1336966) and Defense Advanced Research Projects Agency (DARPA) (No. HR0011-15-2-0021).

Probe pressure effects on human skin diffuse reflectance and fluorescence spectroscopy measurements

PubMed Central

Lim, Liang; Nichols, Brandon; Rajaram, Narasimhan; Tunnell, James W.