Sample records for absorption skin

  1. Skin absorption through atopic dermatitis skin

    DEFF Research Database (Denmark)

    Halling-Overgaard, A-S; Kezic, S; Jakasa, I


    Patients with atopic dermatitis have skin barrier impairment in both lesional and non-lesional skin. They are typically exposed to emollients daily and topical anti-inflammatory medicaments intermittently, hereby increasing the risk of developing contact allergy and systemic exposed to chemicals...... ingredients found in these topical preparations. We systematically searched for studies that investigated skin absorption of various penetrants, including medicaments, in atopic dermatitis patients, but also animals with experimentally induced dermatitis. We identified 40 articles, i.e. 11 human studies...... examining model penetrants, 26 human studies examining atopic dermatitis drugs and 3 animal studies. We conclude that atopic dermatitis patients have nearly two-fold increased skin absorption when compared to healthy controls. There is a need for well-designed epidemiological and dermato...

  2. Epidermal melanin absorption in human skin (United States)

    Norvang Nilsen, Lill T.; Fiskerstrand, Elisanne J.; Nelson, J. Stuart; Berns, Michael W.; Svaasand, Lars O.


    The principle of laser induced selective photothermolysis is to induced thermal damage to specific targets in such a manner that the temperature of the surrounding tissue is maintained below the threshold for thermal damage. The selectivity is obtained by selection of a proper wavelength and pulse duration. The technique is presently being used in the clinic for removal of port-wine stains. The presence of melanin in the epidermal layer can represent a limitation to the selectivity. Melanin absorption drops off significantly with increasing wavelength, but is significant in the entire wavelength region where the blood absorption is high. Treatment of port-wine stain in patients with high skin pigmentation may therefore give overheating of the epidermis, resulting in epidermal necrosis. Melanosomal heating is dependent on the energy and duration of the laser pulse. The heating mechanism for time scales less than typically 1 microsecond(s) corresponds to a transient local heating of the individual melanosomes. For larger time scales, heat diffusion out of the melanosomes become of increased importance, and the temperature distribution will reach a local steady state condition after typically 10 microsecond(s) . For even longer pulse duration, heat diffusing from neighboring melanosomes becomes important, and the temperature rise in a time scale from 100 - 500 microsecond(s) is dominated by this mechanism. The epidermal heating during the typical 450 microsecond(s) pulse used for therapy is thus dependent on the average epidermal melanin content rather than on the absorption coefficient of the individual melanosomes. This study will present in vivo measurements of the epidermal melanin absorption of human skin when exposed to short laser pulses (< 0.1 microsecond(s) ) from a Q-switched ruby laser and with long laser pulses (approximately 500 microsecond(s) ) from a free-running ruby laser or a long pulse length flashlamp pumped dye laser. The epidermal melanin

  3. Role of collagen in terahertz absorption in skin (United States)

    Tewari, Priyamvada; Culjat, Martin O.; Taylor, Zachary D.; Suen, Jonathan Y.; Burt, Benjamin O.; Lee, Hua; Brown, Elliott R.; Grundfest, Warren S.; Singh, Rahul S.


    Reflective terahertz (THz) imaging may potentially become a valuable tool in determining skin hydration due to its non-ionizing photon energy, high sensitivity to water concentration and ability to penetrate through clothing. The high absorption coefficient of water in the THz range is responsible for contrast between substances with lesser or higher degrees of water saturation. Water content, as well as collagen fiber arrangement, varies between different layers of skin. This study sought to determine whether the high THz absorption in water could be exploited to distinguish between these layers. Porcine skin specimens were sectioned into samples of increasing thickness, with the undersides corresponding to different layers in skin. The undersides of the samples were scanned using a THz imaging system operating at a center frequency of 0.5 THz with 0.125 THz of noise-equivalent bandwidth at a standoff of 4 cm and a spot size of 13 mm. Collagen solutions of varying hydrations were also prepared and raster scanned with the same system. The reflectivity of the deeper layers of skin was found to be higher than that of the upper layers, indicating that the deeper layers are more hydrated. The collagen solutions with higher hydration also had higher THz reflectivity. These results suggested that THz is able to distinguish between different layers of skin based on water content and the nature of its association with components in skin.

  4. Near infrared laser penetration and absorption in human skin (United States)

    Nasouri, Babak; Murphy, Thomas E.; Berberoglu, Halil


    For understanding the mechanisms of low level laser/light therapy (LLLT), accurate knowledge of light interaction with tissue is necessary. In this paper, we present a three dimensional, multi-layer Monte Carlo simulation tool for studying light penetration and absorption in human skin. The skin is modeled as a three-layer participating medium, namely epidermis, dermis, and subcutaneous, where its geometrical and optical properties are obtained from the literature. Both refraction and reflection are taken into account at the boundaries according to Snell's law and Fresnel relations. A forward Monte Carlo method was implemented and validated for accurately simulating light penetration and absorption in absorbing and anisotropically scattering media. Local profiles of light penetration and volumetric absorption densities were simulated for uniform as well as Gaussian profile beams with different spreads at 155 mW average power over the spectral range from 1000 nm to 1900 nm. The results show the effects of beam profiles and wavelength on the local fluence within each skin layer. Particularly, the results identify different wavelength bands for targeted deposition of power in different skin layers. Finally, we show that light penetration scales well with the transport optical thickness of skin. We expect that this tool along with the results presented will aid researchers resolve issues related to dose and targeted delivery of energy in tissues for LLLT.

  5. Povidone iodine skin absorption: an ex-vivo study. (United States)

    Nesvadbova, Martina; Crosera, Matteo; Maina, Giovanni; Larese Filon, Francesca


    Povidone iodine is a water-soluble complex used to disinfect the skin surface and it exerts prolonged germicidal action against a broad spectrum of germs. Indeed, it is often applied on burned skin, large wounds, deep tissues or mucosa. Notably some surgical hand-scrub solutions, which are considered safe antiseptics, contain large amounts of iodine that can be absorbed by skin. The aim of present study was to study the skin absorption of iodine after the application on the skin of povidone-iodine solution, used by health care workers during surgical procedure. We use Franz diffusion static cells with human skin. After 24h from the beginning of our measurement the iodine concentration in the receiving compartment was 11.59±6.3μg/cm(2). The medium flux calculated was 0.73±0.33μg/cm(2)/h with a lag time of 8.9±1.5h. These in vitro results confirmed that povidone iodine could pass through the skin in a relevant amount that can explain the clinical findings in burned or surgically treated patients. In professional use the repetitive contact with povidone iodine, also as soap, can cause iodine skin permeation that must be considered when the washing procedures are repeated more than 20 times a day.

  6. Nanoparticles skin absorption: New aspects for a safety profile evaluation. (United States)

    Larese Filon, Francesca; Mauro, Marcella; Adami, Gianpiero; Bovenzi, Massimo; Crosera, Matteo


    Nanoparticles (NPs) skin absorption is a wide issue, which needs to be better understood. The attempt of this review is to summarize the scientific evidence concerning open questions, i.e.: the role of NPs intrinsic characteristics (size, shape, charge, surface properties), the penetration of NPs through the intact or impaired skin barrier, the penetration pathways which should be considered and the role of NPs interaction in physiological media. The outcomes suggest that one main difference should be made between metal and non-metal NPs. Both kinds have a secondary NPs size which is given after interaction in physiological media, and allows a size-dependent skin penetration: NPs⩽4nm can penetrate and permeate intact skin, NPs size between 4 and 20nm can potentially permeate intact and damaged skin, NPs size between 21 and 45nm can penetrate and permeate only damaged skin, NPs size>45nm cannot penetrate nor permeate the skin. Other aspects play an important role, mostly for metal NPs, i.e., dissolution in physiological media, which can cause local and systemic effects, the sensitizing or toxic potential and the tendency to create aggregates. This paper suggests a decision tree to evaluate the potential risk for consumers and workers exposed to NPs.

  7. Dermal absorption and skin damage following hydrofluoric acid exposure in an ex vivo human skin model. (United States)

    Dennerlein, Kathrin; Kiesewetter, Franklin; Kilo, Sonja; Jäger, Thomas; Göen, Thomas; Korinth, Gintautas; Drexler, Hans


    The wide industrial use of hydrofluoric acid (HF) poses a high risk for accidental dermal exposure. Despite local and systemic hazards associated with HF, information on percutaneous penetration and tissue damage is rare. In the present ex vivo study, the dermal absorption of HF (detected in terms of fluoride ions) was quantified and the skin damaging potential as a function of concentration and exposure duration was assessed. Percutaneous penetration of HF (c=5, 30, and 50%) at 3 exposure durations (3, 5, and 10 min) was investigated in a static diffusion cell model using freshly excised human skin. Alterations of skin were histologically evaluated. HF rapidly penetrated through skin under formation of a considerable intradermal reservoir (∼ 13-67% of total absorbed fluoride). Histologically, epidermal alterations were detected already after exposure to 5% HF for 3 min. The degree of skin damage increased with rising concentration and exposure duration leading to coagulation necrosis. For HF concentrations of ≥ 30%, skin damage progressed into deeper skin layers. Topically applied HF concentration was the principal parameter determining HF induced skin effects. The intradermal HF retention capacity associated with progression and prolongation of HF induced skin effects must be considered in the review of skin decontamination procedures.

  8. Skin absorption of six performance amines used in metalworking fluids. (United States)

    Roux, Lauriane N; Brooks, James D; Yeatts, James L; Baynes, Ronald E


    Every year, 10 million workers are exposed to metalworking fluids (MWFs) that may be toxic. There are four types of MWFs: neat oils and three water-based MWFs (soluble oil, semisynthetic and synthetic), which are diluted with water and whose composition varies according to the mineral oils ratio. MWFs also contain various additives. To determine the absorption of six amines used as corrosion inhibitors and biocides in MWFs, porcine skin flow-through diffusion cell experiments were conducted with hydrophilic ethanolamines (mono-, di- and triethanolamine, MEA, DEA and TEA respectively) and a mixture of lipophilic amines (dibutylethanolamine, dicyclohexylamine and diphenylamine). The six amines were dosed in four vehicles (water and three generic water-based MWF formulations) and analyzed using a scintillation counter or gas chromatography/mass spectrometry. These 24 h studies showed that dermal absorption significantly (P < 0.05) increased from water for the six amines (e.g. 1.15 ± 0.29% dose; DEA in water) compared to other formulations (e.g. 0.13 ± 0.01% dose; DEA in semisynthetic MWF) and absorption was greatest for dibutylethanolamine in all the formulations. The soluble oil formulation tended to increase the dermal absorption of the hydrophilic amines. The permeability coefficient was significantly higher (P < 0.05) with TEA relative to the other hydrophilic amines (e.g. 4.22 × 10(-4) ± 0.53 × 10(-4) cm h(-1) [TEA in synthetic MWF] vs. 1.23 × 10(-4) ± 0.10 × 10(-4) cm h(-1) [MEA in synthetic MWF]), except for MEA in soluble oil formulation. Future research will confirm these findings in an in vivo pig model along with dermatotoxicity studies. These results should help MWF industries choose safer additives for their formulations to protect the health of metalworkers.

  9. In vitro absorption of metal powders through intact and damaged human skin. (United States)

    Filon, Francesca Larese; D'Agostin, Flavia; Crosera, Matteo; Adami, Gianpiero; Bovenzi, Massimo; Maina, Giovanni


    The bioavailability of metals, which are known as important contact allergens, is decisive for the development and the maintenance of contact dermatitis. The aim of this study was to evaluate the percutaneous penetration of metal powders of cobalt (Co), nickel (Ni) and chromium (Cr) and the effect of skin lesions on skin absorption. In vitro permeation experiments were performed using the Franz diffusion cells with intact and damaged human skin. Physiological solution was used as receiving phase and metal powders (Co, Ni and Cr) dispersed in synthetic sweat at pH 4.5 were applied as donor phase to the outer surface of the skin for 24h. The amount of each metal permeating the skin was analysed by electro-thermal atomic absorption spectroscopy (ETAAS). Donor solution analysis demonstrated that metals were present as ions. Measurements of metals skin content were also exploited. Median Co and Ni concentrations found in the receiving phase were significantly higher when Co and Ni powders were applied on the abraded skin than after application on the intact skin (3566 and 2631ngcm(-2) vs. 8.4 and 31ngcm(-2), respectively). No significant difference was found in Cr permeation through intact and damaged skin. The measurement of metals skin content showed that Co, Ni and Cr concentrations were significantly higher in the damaged skin than in the intact skin. Co and Ni ions concentrations increased significantly when the donor solutions were applied on the damaged skin, while Cr ions concentrations did not increase. This study demonstrated that Co and Ni powders can permeate through damaged skin more easily than Cr powder, which has probably a stronger skin proteins binding capacity. Therefore, our results suggest that is necessary to prevent skin contamination when using toxic substances because a small injury to the skin barrier can significantly increase skin absorption.

  10. Suitability of skin integrity tests for dermal absorption studies in vitro. (United States)

    Guth, Katharina; Schäfer-Korting, Monika; Fabian, Eric; Landsiedel, Robert; van Ravenzwaay, Ben


    Skin absorption testing in vitro is a regulatory accepted alternative method (OECD Guideline 428). Different tests can be applied to evaluate the integrity of the skin samples. Here, we compared the pre- or post-run integrity tests (transepidermal electrical resistance, TEER; transepidermal water loss, TEWL; absorption of the reference compounds water, TWF, or methylene blue, BLUE) and additionally focused on co-absorption of a (3)H-labeled internal reference standard (ISTD) as integrity parameter. The results were correlated to absorption profiles of various test compounds. Limit values of 2kΩ, 10 gm(-2)h(-1) and 4.5∗10(-3)cmh(-1) for the standard methods TEER, TEWL and TWF, respectively, allowed distinguishing between impaired and intact human skin samples in general. Single skin samples did, however, not, poorly and even inversely correlate with the test-compound absorption. In contrast, results with ISTD (e.g. (3)H-testosterone) were highly correlated to the absorption of (14)C-labeled test compounds. Importantly, ISTD did not influence analytics or absorption of test compounds. Therefore, ISTD, especially when adjusted to the physico-chemical properties of test compounds, is a promising concept to assess the integrity of skin samples during the whole course of absorption experiments. However, a historical control dataset is yet necessary for a potential routine application.

  11. Absorption of human skin and its detecting platform in the process of laser cosmetology (United States)

    Zhang, Yong-Lin; Ouyang, Li; Wang, Yang


    Because of the melanin, hemoglobin and water molecules, etc. contained, light absorption of human skin tissue changes with wavelength of light. This is the principle used in laser cosmetology for treating pigment diseases and vascular lesion diseases as well as skin decoration such as body tattooing, eyebrow tattooing, etc. The parameters of treatment used in laser cosmetology principally come from the research of the skin tissue optical characteristics of whites, and it is not suitable for the Oriental. The absorption spectrum of yellow race alive skin has been researched. The detecting platform for use in the measuring of vivi-tissue absorption spectrum has been developed which using opto-electronic nondestructive testing and virtual instrument techniques. The degree of pathological changes of skin can be detected by this platform also, thus the shortcoming of dosage selection in laser clinical treatments which have been decided only by naked eye observation and past experience of doctors can be solved.

  12. [In vitro percutaneous absorption of chromium powder and the effect of skin cleanser]. (United States)

    D'Agostin, F; Crosera, M; Adami, G; Malvestio, A; Rosani, R; Bovenzi, M; Maina, G; Filon, F Larese


    Occupational chromium dermatitis occurs frequently among cement and metal workers, workers dealing with leather tanning and employees in the ceramic industry. The present study, using an in-vitro system, evaluated percutaneous absorption of chromium powder and the effect of rapid skin decontamination with a common detergent. Experiments were performed using the Franz diffusion cell method with human skin. Physiological solution was used as receiving phase and a suspension of chromium powder in synthetic sweat was used as donor phase. The tests were performed without or with decontamination using the cleanser 30 minutes after the start of exposure. The amount of chromium permeated through the skin was analysed by Inductively Coupled Plasma Atomic Emission Spectroscopy and Electro Thermal Atomic Absorption Spectroscopy. Speciation analysis and measurements of chromium skin content were also performed. We calculated a permeation flux of 0.843 +/- 0.25 ng cm(-2) h(-1) and a lag time of 1.1 +/- 0.7 h. The cleaning procedure significantly increased chromium skin content, whereas skin passage was not increased. These results showed that chromium powder can pass through the skin and that skin decontamination did not decrease skin absorption. Therefore, it is necessary to prevent skin contamination when using toxic agents.

  13. Acoustic absorption measurement of human hair and skin within the audible frequency range. (United States)

    Katz, B F


    Utilizing the two-microphone impedance tube method, the acoustic absorption of human skin and hair is measured in the frequency range 1-6 kHz. Various locations on a number of human subjects are measured to determine if the presence of bone or an air pocket affects the acoustic absorption of human skin. The absorption coefficient of human hair is also measured. Additional techniques are utilized to minimize errors due to sample mounting methods. Techniques are employed to minimize potential errors in sensor and sample locations. The results of these measurements are compared to relevant historical papers on similar investigations. Results for skin measurements compare well with previous work. Measured hair absorption data do not agree with previous work in the area but do coincide with expected trends, which previous works do not.

  14. Anti-melasma codrug of retinoic acid assists cutaneous absorption with attenuated skin irritation. (United States)

    Hsieh, Pei-Wen; Hung, Chi-Feng; Lin, Chih-Hung; Huang, Chang-Wei; Fang, Jia-You


    Melasma treatment with combined retinoic acid (RA) and hydroquinone (HQ) usually causes unsatisfactory outcomes and safety concerns. This study attempted to evaluate the cutaneous absorption and skin tolerance of the codrug conjugated with RA and HQ via ester linkage. The codrug's permeation of the pig skin was estimated using Franz diffusion cell. The codrug and parent drugs were comparatively examined for anti-inflammatory activity and tyrosinase inhibition. In vivo cutaneous irritation was assessed on nude mouse skin. Chemical conjugation of RA with HQ increased the lipophilicity and thus the skin absorption. The codrug absorption produced a 5.5- and a 60.8-fold increment compared to RA skin deposition at an equimolar (1.2mM) and saturated solubility dose, respectively. The cumulative amount of HQ derived from the codrug in the receptor was comparable to or less than that of topically applied HQ. The RA-HQ codrug was partly hydrolyzed on penetrating the skin. The hydrolysis rate in intact skin was significantly lower than that in esterase medium and skin homogenates. The codrug showed an interleukin (IL)-6 inhibition activity comparable to RA. A therapeutic index 6-fold greater than RA was obtained with the topical codrug. The tyrosinase inhibition percentage of the codrug and HQ was 13% and 21%, respectively. The skin tolerance test determined by transepidermal water loss (TEWL), redness, and histopathology had exhibited minor skin irritation caused by the codrug compared to the physical mixture of RA and HQ at an equivalent dose. Topical codrug delivery not only promoted RA absorption, but also diminished the adverse effects of the parent agents.

  15. In vitro percutaneous absorption of chromium powder and the effect of skin cleanser. (United States)

    Larese Filon, Francesca; D'Agostin, Flavia; Crosera, Matteo; Adami, Gianpiero; Bovenzi, Massimo; Maina, Giovanni


    The present study tried to investigate, using a synthetic sweat at pH 4.5, whether metallic chromium can pass through the skin (in vitro) and the effect of rapid skin decontamination with a common detergent. A suspension of chromium powder in synthetic sweat at pH 4.5 was prepared and shaken with a stirring plate at room temperature for 30 min. Human skin membranes were set up in Franz-diffusion cells and 1 ml of the freshly made suspension was applied to the outer surface of the skin for 24h. The tests were performed without and with decontamination using the cleanser 30 min after the start of exposure. The appearance of metal ions in the aqueous receptor phase was quantified by Electro Thermal Atomic Absorption Spectroscopy (ETAAS) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). Speciation analysis and measurements of chromium skin content were also performed. Chromium skin permeation was demonstrated in in vitro experiments using the Franz cell system, giving a permeation flux of 0.84+/-0.25 ng cm(-2)h(-1) and a lag time of 1.1+/-0.7h. The cleaning procedure stop Cr permeation but its concentration into the skin significantly increased (Mann-Whitney U test P<0.03). The results revealed that chromium applied as powder can pass through the skin and that decontamination, done after 30 min of exposure, prevent Cr skin permeation but increase Cr content into the skin.

  16. The Phenion (R) Full-Thickness Skin Model for Percutaneous Absorption Testing



    In recent years many efforts have been made to replace dermal toxicity testing of chemicals in the animal by in vitro assays. As a member of a German research consortium, we have previously contributed to the validation of an in vitro test protocol for percutaneous absorption studies on the basis of reconstructed human epidermis and both human and pig skin ex vivo. Aiming to assess the barrier properties of a newly developed reconstructed skin model, this protocol has now been transferred to ...

  17. Influence of different layers of skin on the percutaneous absorption of drugs with different lipophilicity

    Institute of Scientific and Technical Information of China (English)

    LI Guo-feng; Kamiyama Fumio; LIU Li-jie; Yamamoto Akira; CHEN Jian-hai


    Objectives: To evaluate the barrier function of different skin layers in the process of percutaneous drug absorption. Methods: In vitro permeability via intact or stripped skin of 6 drugs (5-fluorouracil, theophylline, hydroquinone, barbital, isosorbide dinitrate and ketoprofen) with a wide span of lipophilicity were investigated in the patch dosage forms. Results: Characteristic parabolic relations was observed between the permeability (Kp, cm/h) of the drugs with different lipophilicity and their LogPc via either intact or stripped skin. However, due to the absence of the stratum corneum, increased Kp ratio for the tested drugs was proportional to their solubility in water other than their LogKp. When isopropyl myristate was used as absorption promoter of the drugs, the parabolic relationship no longer existed. For the intact skin, increase of Kp ratio of the drugs was enhanced resulting from IPM as drug's LogPc decreased. On the other hand, in the case of stripped skin, this enhancement was positively related to the solubility of the drugs in IPM. Conclusion: These data and methods present a novel approach to describe percutaneous drug absorption via damaged or diseased skin.

  18. Absorption spectra and light penetration depth of normal and pathologically altered human skin (United States)

    Barun, V. V.; Ivanov, A. P.; Volotovskaya, A. V.; Ulashchik, V. S.


    A three-layered skin model (stratum corneum, epidermis, and dermis) and engineering formulas for radiative transfer theory are used to study absorption spectra and light penetration depths of normal and pathologically altered skin. The formulas include small-angle and asymptotic approximations and a layer-addition method. These characteristics are calculated for wavelengths used for low-intensity laser therapy. We examined several pathologies such as vitiligo, edema, erythematosus lupus, and subcutaneous wound, for which the bulk concentrations of melanin and blood vessels or tissue structure (for subcutaneous wound) change compared with normal skin. The penetration depth spectrum is very similar to the inverted blood absorption spectrum. In other words, the depth is minimal at blood absorption maxima. The calculated absorption spectra enable the power and irradiation wavelength providing the required light effect to be selected. Relationships between the penetration depth and the diffuse reflectance coefficient of skin (unambiguously expressed through the absorption coefficient) are analyzed at different wavelengths. This makes it possible to find relationships between the light fields inside and outside the tissue.

  19. P-Glycoprotein in skin contributes to transdermal absorption of topical corticosteroids. (United States)

    Hashimoto, Naoto; Nakamichi, Noritaka; Yamazaki, Erina; Oikawa, Masashi; Masuo, Yusuke; Schinkel, Alfred H; Kato, Yukio


    ATP binding cassette transporters, P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), are expressed in skin, but their involvement in transdermal absorption of clinically used drugs remains unknown. Here, we examined their role in transdermal absorption of corticosteroids. Skin and plasma concentrations of dexamethasone after dermal application were reduced in P-gp and BCRP triple-knockout (Mdr1a/1b/Bcrp(-/-)) mice. The skin concentration in Mdr1a/1b/Bcrp(-/-) mice was reduced in the dermis, but not in the epidermis, indicating that functional expression of these transporters in skin is compartmentalized. Involvement of these transporters in dermal transport of dexamethasone was also supported by the observation of a higher epidermal concentration in Mdr1a/1b/Bcrp(-/-) than wild-type mice during intravenous infusion. Transdermal absorption after dermal application of prednisolone, but not methylprednisolone or ethinyl estradiol, was also lower in Mdr1a/1b/Bcrp(-/-) than in wild-type mice. Transport studies in epithelial cell lines transfected with P-gp or BCRP showed that dexamethasone and prednisolone are substrates of P-gp, but are minimally transported by BCRP. Thus, our findings suggest that P-gp is involved in transdermal absorption of at least some corticosteroids in vivo. P-gp might be available as a target for inhibition in order to deliver topically applied drugs and cosmetics in a manner that minimizes systemic exposure.

  20. Microencapsulation decreases the skin absorption of N,N-diethyl-m-toluamide (DEET). (United States)

    Kasting, Gerald B; Bhatt, Varsha D; Speaker, Tycho J


    The insect repellent N,N-diethyl-3-methylbenzamide (DEET) is widely used and is generally regarded as safe when used according to label instructions. Yet many studies have shown it to be absorbed through the skin. The objective of this study was to determine whether the skin absorption rate of DEET could be decreased while maintaining an evaporation rate consistent with effective repellency. To this end, an aqueous suspension containing 14C-DEET (15%w/w) entrapped in walled polysaccharide microcapsules was prepared and tested for skin absorption in vitro using modified Franz cells maintained in a fume hood. The control formulation was 15%w/w DEET in ethanol. Two doses (3 microL and 5 microL per 0.79 cm2 cell) of each formulation were applied to split-thickness human cadaver skin (n=8/dose), and permeation was monitored for 24h. The microencapsulated DEET formulation lead to a 25-35% reduction of radiolabel permeation compared to the ethanolic DEET formulation. Skin levels of radioactivity at 24h were comparable, indicating that DEET evaporation from the microencapsulated formulation was comparable to or greater than that from ethanol. Hence microencapsulation increased the ratio of DEET evaporation rate to skin penetration rate relative to unencapsulated control in this in vitro study.

  1. The use of reconstructed human epidermis for skin absorption testing: Results of the validation study. (United States)

    Schäfer-Korting, Monika; Bock, Udo; Diembeck, Walter; Düsing, Hans-Jürgen; Gamer, Armin; Haltner-Ukomadu, Eleonore; Hoffmann, Christine; Kaca, Monika; Kamp, Hennicke; Kersen, Silke; Kietzmann, Manfred; Korting, Hans Christian; Krächter, Hans-Udo; Lehr, Claus-Michael; Liebsch, Manfred; Mehling, Annette; Müller-Goymann, Christel; Netzlaff, Frank; Niedorf, Frank; Rübbelke, Maria K; Schäfer, Ulrich; Schmidt, Elisabeth; Schreiber, Sylvia; Spielmann, Horst; Vuia, Alexander; Weimer, Michaela


    A formal validation study was performed, in order to investigate whether the commercially-available reconstructed human epidermis (RHE) models, EPISKIN, EpiDerm and SkinEthic, are suitable for in vitro skin absorption testing. The skin types currently recommended in the OECD Test Guideline 428, namely, ex vivo human epidermis and pig skin, were used as references. Based on the promising outcome of the prevalidation study, the panel of test substances was enlarged to nine substances, covering a wider spectrum of physicochemical properties. The substances were tested under both infinite-dose and finite-dose conditions, in ten laboratories, under strictly controlled conditions. The data were subjected to independent statistical analyses. Intra-laboratory and inter-laboratory variability contributed almost equally to the total variability, which was in the same range as that in preceding studies. In general, permeation of the RHE models exceeded that of human epidermis and pig skin (the SkinEthic RHE was found to be the most permeable), yet the ranking of substance permeation through the three tested RHE models and the pig skin reflected the permeation through human epidermis. In addition, both infinite-dose and finite-dose experiments are feasible with RHE models. The RHE models did not show the expected significantly better reproducibility, as compared to excised skin, despite a tendency toward lower variability of the data. Importantly, however, the permeation data showed a sufficient correlation between all the preparations examined. Thus, the RHE models, EPISKIN, EpiDerm and SkinEthic, are appropriate alternatives to human and pig skin, for the in vitro assessment of the permeation and penetration of substances when applied as aqueous solutions.

  2. Dermal toxicity elicited by phthalates: evaluation of skin absorption, immunohistology, and functional proteomics. (United States)

    Pan, Tai-Long; Wang, Pei-Wen; Aljuffali, Ibrahim A; Hung, Yi-Yun; Lin, Chwan-Fwu; Fang, Jia-You


    The toxicity of phthalates is an important concern in the fields of environmental health and toxicology. Dermal exposure via skin care products, soil, and dust is a main route for phthalate delivery. We had explored the effect of topically-applied phthalates on skin absorption and toxicity. Immunohistology, functional proteomics, and Western blotting were employed as methodologies for validating phthalate toxicity. Among 5 phthalates tested, di(2-ethylhexyl)phthalate (DEHP) showed the highest skin reservoir. Only diethyl phthalate (DEP) and dibutyl phthalate (DBP) could penetrate across skin. Strat-M(®) membrane could be used as permeation barrier for predicting phthalate penetration through skin. The accumulation of DEHP in hair follicles was ∼15nmol/cm(2), which was significantly greater than DBP and DEP. DBP induced apoptosis of keratinocytes and fibroblasts via caspase-3 activation. This result was confirmed by downregulation of 14-3-3 and immunohistology of TUNEL. On the other hand, the HSP60 overexpression and immunostaining of COX-2 suggested inflammatory response induced by DEP and DEHP. The proteomic profiling verified the role of calcium homeostasis on skin inflammation. Some proteins investigated in this study can be sensitive biomarkers for dermal toxicity of phthalates. These included HSPs, 14-3-3, and cytokeratin. This work provided novel platforms for examining phthalate toxicity on skin.

  3. Regional variations in percutaneous absorption of methimazole: an in vitro study on cat skin. (United States)

    Hill, K E; Chambers, J P; Jones, B R; Bolwell, C F; Aberdein, D; Mills, P C


    The use of transdermal gel medications in cats has become popular in veterinary medicine due to the ease of administration compared to oral medication. The research to support systemic absorption of drugs after transdermal gel administration and the preferred skin region to apply these drugs in cats is limited. The aim of this study was to characterize the effect of different skin regions on the percutaneous absorption pharmacokinetics of a commercially available transdermal methimazole after a finite dose was applied to feline skin in vitro. A commercial formulation of methimazole (10 mg) was applied to four skin regions (the inner stratum corneum of the ear, groin, neck, and thorax regions) from six cats. The receptor medium was sampled up to 36 h postapplication, and methimazole concentrations were measured using high-performance liquid chromatography. Methimazole was absorbed more completely across the pinnal skin, compared to the groin, neck, and thorax (P < 0.001), which justifies application to the pinna to maximize efficacy and also to minimize the effects of grooming.

  4. Methamphetamine absorption by skin lipids: accumulated mass, partition coefficients, and the influence of fatty acids. (United States)

    Parker, K; Morrison, G


    Occupants of former methamphetamine laboratories, often residences, may experience increased exposure through the accumulation of the methamphetamine in the organic films that coat skin and indoor surfaces. The objectives of this study were to determine equilibrium partition coefficients of vapor-phase methamphetamine with artificial sebum (AS-1), artificial sebum without fatty acids (AS-2), and real skin surface films, herein called skin oils. Sebum and skin oil-coated filters were exposed to vapor-phase methamphetamine at concentrations ranging from 8 to 159 ppb, and samples were analyzed for exposure time periods from 2 h to 60 days. For a low vapor-phase methamphetamine concentration range of ~8-22 ppb, the equilibrium partition coefficient for AS-1 was 1500 ± 195 μg/g/ppb. For a high concentration range of 98-112 ppb, the partition coefficient was lower, 459 ± 80 μg/g/ppb, suggesting saturation of the available absorption capacity. The low partition coefficient for AS-2 (33 ± 6 μg/g/ppb) suggests that the fatty acids in AS-1 and skin oil are responsible for much high partition coefficients. We predict that the methamphetamine concentration in skin lipids coating indoor surfaces can exceed recommended surface remediation standards even for air concentrations well below 1 ppb.

  5. In vitro skin absorption and metabolism of benzoic acid, p-aminobenzoic acid, and benzocaine in the hairless guinea pig. (United States)

    Nathan, D; Sakr, A; Lichtin, J L; Bronaugh, R L


    The percutaneous absorption and metabolism of three structurally related compounds, benzoic acid, p-aminobenzoic acid (PABA), and ethyl aminobenzoate (benzocaine), were determined in vitro through hairless guinea pig skin. Benzocaine was also studied in human skin. Absorption of benzocaine was rapid and similar through both viable and nonviable skin. The absorption of the two acidic compounds, benzoic acid and PABA, was greater through nonviable skin. A small portion (6.9%) of absorbed benzoic acid was conjugated with glycine to form hippuric acid. Although N-acetyl-benzocaine had not been observed as a metabolite of benzocaine when studied by other routes of administration, both PABA and benzocaine were extensively N-acetylated during percutaneous absorption. Thus, the metabolism of these compounds should be considered in an accurate assessment of absorption after topical application.

  6. Role of transepidermal and transfollicular routes in percutaneous absorption of steroids: in vitro studies on human skin. (United States)

    Hueber, F; Schaefer, H; Wepierre, J


    Percutaneous absorption theoretically comprises two components: the transepidermal and the transfollicular routes. The aim of the present work was to confirm this hypothesis in the human skin by comparing the in vitro percutaneous absorption of four steroids through scar skin without hair follicles and sebaceous glands and through normal adjacent skin from abdominal or mammary plasties. In all cases, the absorption of the four steroids was significantly higher in normal skin than in scar skin. The cumulative percentages of progesterone and testosterone after 8 h of application were, respectively, 3.1- and 2.4-fold higher in normal skin than in scar skin. After 24 h of application, the cumulative percentages of estradiol and hydrocortisone were 1.7- and 2.4-fold higher in normal skin than in scar skin. At the end of the experiments, the quantities of drugs remaining in the skin after 8 or 24 h of application were the same in normal skin and in scar skin except for progesterone for which they were 2-fold greater in normal than in scar skin. In each case, a histological characterization of the scar skin was made in comparison with the normal adjacent skin. The main modifications observed on scar skin were the following: absence of hair follicles and sebaceous glands, thinning of the collagenous fibers with parallel orientation to the dermoepidermal junction and decrease in the number or disappearance of the elastic fibers. These experiments confirmed that human skin appendages, hair follicles and sebaceous glands, constitute a route of penetration for steroids and thus probably for other chemicals of similar molecular weight and properties.

  7. Photoacoustic study of percutaneous absorption of Carbopol and transdermic gels for topic use in skin (United States)

    Rossi, R. C. P.; de Paiva, R. F.; da Silva, M. D.; Barja, P. R.


    Topical medicine application has been used to treat a good number of pathological processes. Its efficacy is associated to an efficient penetration of the drug in the internal skin layers, promoting systemic effects and excluding the possibility of drug degradation by the digestive tract and hepatic elimination. This work analyzes the penetration kinetics of two soluble bases employed as vehicles for topic application: superficial gel (Carbopol 940) and transdermic (transdermal) gel. Analysis was performed with the photoacoustic technique, based upon the absorption of modulated light by a sample with subsequent conversion of the absorbed energy in heat, generating acoustic waves in the air layer adjacent to the sample. Each of the two vehicles was evaluated through in vivo (human skin) and in vitro application. Measurements in vitro employed samples of VitroSkin (synthetic material with properties similar to those of real skin, employed in the pharmaceutical industry research). Results show that the permeation was faster for the transdermal gel, both for in vivo and in vitro measurements, indicating that in vitro measurements may be utilized in qualitative, comparative permeation studies.

  8. LASER METHODS IN MEDICINE: Light absorption in blood during low-intensity laser irradiation of skin (United States)

    Barun, V. V.; Ivanov, A. P.


    An analytical procedure is proposed for describing optical fields in biological tissues inhomogeneous in the depth direction, such as human skin, with allowance for multiple scattering. The procedure is used to investigate the depth distribution of the optical power density in homogeneous and multilayer dermis when the skin is exposed to a laser beam. We calculate the absorbed laser power spectra for oxy- and deoxyhaemoglobin at different depths in relation to the absorption selectivity of these haemoglobin derivatives and the spectral dependence of the optical power density and demonstrate that the spectra vary considerably with depth. A simple exponential approximation is proposed for the depth distribution of the power density in the epidermis and dermis.

  9. In vitro predictions of skin absorption of caffeine, testosterone, and benzoic acid: A multi-centre comparison study

    NARCIS (Netherlands)

    Sandt, J.J.M. van de; Burgsteden, J.A. van; Cage, S.; Carmichael, P.L.; Dick, I.; Kenyon, S.; Korinth, G.; Larese, F.; Limasset, J.C.; Maas, W.J.M.; Montomoli, L.; Nielsen, J.B.; Payan, J.-P.; Robinson, E.; Sartorelli, P.; Schaller, K.H.; Wilkinson, S.C.; Williams, F.M.


    To obtain better insight into the robustness of in vitro percutaneous absorption methodology, the intra- and inter-laboratory variation in this type of study was investigated in 10 European laboratories. To this purpose, the in vitro absorption of three compounds through human skin (9 laboratories)

  10. Absorption and metabolism of 2-chloro-2,6-diethyl-N-(butoxymethyl)acetanilide (butachlor) in human skin in vitro. (United States)

    Ademola, J I; Wester, R C; Maibach, H I


    Studies have demonstrated that several chemicals are absorbed and metabolized during skin permeation. We investigated the absorption and metabolism of the pesticide butachlor. Radiolabeled butachlor was measured in human (n = 5) skin and the unchanged compound and metabolites were quantified by high-pressure liquid chromatography (HPLC) and thin-layer chromatography (TLC). Following a 24-hr exposure, an average butachlor quantity of approximately 5.00% of the applied dose (1.01 micrograms) was absorbed by the skin. The mean peak penetration rate was 0.7% of the applied dose per hour. The skin retained 1.40 to 8.10% of the applied butachlor. The retention of 1.4 to 8.1% of the pesticide by the skin suggests the importance of monitoring human skin following topical exposure. Of the dose recovered in the skin, 0.9% was metabolized to 4-hydroxybutachlor, while 1.8% of the dose in the receptor fluid was recovered as polar conjugates (cysteine, 0.29% dose; glutathione, 0.1% dose; unidentified metabolites, 1.4% dose); 2.8 and 6.8% of the dose absorbed by the skin (approximately 5.0%) were recovered as metabolites in the receptor fluids and skin homogenates, respectively. Similar to metabolism during percutaneous absorption, butachlor was metabolized to its conjugated and hydroxyl derivatives by skin fractions. The rate of butachlor glutathione and butachlor cysteine formation using skin cytosolic fractions were 12.0 +/- 1.5 and 48.0 +/- 3.6 pmol/min/mg protein +/- SD, respectively. When human skin microsomes were incubated with butachlor, 4-hydroxybutachlor was formed at the rate of 55.0 +/- 15.0 pmol/min/mg protein +/- SD. 4-Hydroxybutachlor formation was totally dependent on the presence of NADPH. The biotransformation of butachlor using skin fractions indicates the metabolic capacity of the tissue. The biological significance of these metabolites in the disposition of butachlor requires further investigation.

  11. Percutaneous Absorption and Metabolism of Ketoprofen Isopropyl Ester via Excised Nude Mouse‘s and Monkey’s Skin

    Institute of Scientific and Technical Information of China (English)

    ZHUQuan-gang; HUJin-hong


    Aim:To study percutaneous absorption and metabolism of ketoprofen isopropyl ester (KPE)via excised nude mouse's and monkey's skin.Methods:Excised skin was prepared by surgical excision and enzyme digestion.Sideby-side diffusion cells were used for in vitro permeation studies.The concentrations of KPE and its metabolite in samples were assayed by HPLC.Results:All KPE penetration through whole thickness skin and stripped skin was metabolized to ketoprofen(KP).the concentration of which in the reciiver solution increased linearly with time.As to the nude mouse skin.the steady-state flux of KP through whole thickness skin was 2.5 times that of KPE through the whloe thickness skin,but the KP and KPE remaining in the whole thickness skin after the finishing of KPE penetration was 22.2 times in compered with the KP remaining in the whole thickness skin after the finshing of KP penetration.The rate of formation of the steady state KP from KPE throught dermis was significantly lower than that of KPE through the whole thickness skin.In he monkey skin,the rate of formation of the steady-state KP from KPE through the whole thickness skin was 0.7 times that from KPE through stripped skin.The KP and KPE remaining in the whole thickness skin after the finishing of KPE penetration was 2.0 time that in the stripped skin after the finishing of KPE penetration.The rate of fornation of the steady-state KP from KPE through dermis was lower than that from KPE through the whole thickness skin and the stripped skin.the KP remaining in dermis after the finsihing of KPE penetration was also significantly lower than the KP remaining in the whole thickness skin and the stripped skin after the finishing of KPE penetration.Conclusion:KP esters are of benefit to imporove the local action of KP.and skin esterase metabolism mainly develops in the epidermis.

  12. Absorption of the nerve agent VX (O-ethyl-S-[2(di-isopropylamino)ethyl] methyl phosphonothioate) through pig, human and guinea pig skin in vitro. (United States)

    Dalton, Christopher H; Hattersley, Ian J; Rutter, Stephen J; Chilcott, Robert P


    The physico-chemical properties of VX make the skin the most likely route of absorption into the human body. The development of effective medical countermeasures against such percutaneous threat agents relies on the use of appropriate animal models, as the inherent toxicity of nerve agents precludes the use of human volunteers. Previous studies have characterised the mechanism of nerve agent toxicity in rodent models, however, it is generally accepted that one of the most appropriate animal models for human skin absorption is the domestic pig. The purpose of the present study was to measure and compare the skin absorption kinetics of VX in vitro using pig, human and guinea pig skin to highlight any potential species differences in skin permeability. When undiluted VX was applied directly to the skin, the permeability of guinea pig skin was approximately 7-fold greater than human skin. There was no significant difference in the permeability of pig and human skin. When VX diluted with isopropyl alcohol was applied to the skin, the permeability of guinea pig skin was approximately 4-fold greater than human skin. There was no significant difference in the permeability of pig and human skin. From this data it may be inferred that dermatomed, abdominal pig skin is an appropriate model for the human skin absorption of VX.

  13. In-vitro percutaneous absorption of losartan potassium in human skin and prediction of human skin permeability

    Directory of Open Access Journals (Sweden)

    Petkar K.C.


    Full Text Available This study describes the feasibility of transdermal controlled administration of Losartan potassium (LP across human cadaver skin. Study also defines the influence of capsaicin, sex and site of application on permeation characteristics and determined an appropriate animal model for human skin permeability. The permeation of LP of various formulations was studied using Keshary-Chein diffusion cell. Optimized controlled formulation (without capsaicin released 42.17% (±1.85 of LP in 12 hr whereas treatment formulation (with capsaicin 0.028 % w/v released 48.94% (±1.71 of LP with significant difference on null hypothesis. Influence of sex showed statistically significant difference for permeation of LP through male and female rats, as well as male and female mice across both the abdominal and dorsal sides of the skin (p<0.05. Similarly statistically significant differences were noted for permeation of LP across male and female mice abdomen-dorsal, but not for male rat abdomen-dorsal and female rat abdomen-dorsal. Furthermore, in-vitro permeation of LP across human skin was compared with the permeation across rat and mice skins. Male rat and male mice dorsal skin was found to have closer permeability characteristics to human than other skin membranes, but the Factor of Difference values were < 3 for all membranes which were used suggesting the membranes are good models for human skin permeability. In conclusion simple transdermal adhesive patches formulations incorporating high molecular weight of LP can deliver a dose in-vivo and proposed model skin membranes can be utilized for future pharmacokineic and toxicokinetic studies as well as metabolism studies of LP

  14. The absorption and metabolism of a single L-menthol oral versus skin administration: Effects on thermogenesis and metabolic rate. (United States)

    Valente, Angelica; Carrillo, Andres E; Tzatzarakis, Manolis N; Vakonaki, Elena; Tsatsakis, Aristidis M; Kenny, Glen P; Koutedakis, Yiannis; Jamurtas, Athanasios Z; Flouris, Andreas D


    We investigated the absorption and metabolism pharmacokinetics of a single L-menthol oral versus skin administration and the effects on human thermogenesis and metabolic rate. Twenty healthy adults were randomly distributed into oral (capsule) and skin (gel) groups and treated with 10 mg kg(-1) L-menthol (ORALMENT; SKINMENT) or control (lactose capsule: ORALCON; water application: SKINCON) in a random order on two different days. Levels of serum L-menthol increased similarly in ORALMENT and SKINMENT (p > 0.05). L-menthol glucuronidation was greater in ORALMENT than SKINMENT (p  0.05). Participants reported no cold, shivering, discomfort, stress or skin irritation. We conclude that a single L-menthol skin administration increased thermogenesis and metabolic rate in humans. These effects are minor following L-menthol oral administration probably due to faster glucuronidation and greater blood menthol glucuronide levels.

  15. In vitro Percutaneous Absorption of Niacinamide and Phytosterols and in vivo Evaluation of their Effect on Skin Barrier Recovery. (United States)

    Offerta, Alessia; Bonina, Francesco; Gasparri, Franco; Zanardi, Andrea; Micicche, Lucia; Puglia, Carmelo


    In this study, we evaluated different strategies to optimize the percutaneous absorption of niacinamide (NA) and soy phytosterols (FITO) by making use of solid lipid nanoparticles (SLN) and penetration enhancers, such as the hydrogenated lecithin. The evaluation of the skin permeation of NA and FITO has been effected in vitro using excised human skin (i.e., stratum corneum-epidermis or SCE). Furthermore, we evaluated the in vivo effect that NA and FITO has on skin barrier recovery after the topical application; using the extent of methyl nicotinate (MN)-induced erythema in damaged skin as a parameter to determine the rate of stratum corneum recovery. Results pointed out the importance of these strategies as valid tools for NA and FITO topical delivery. In fact, soy lecithin based formulations were able to increase the percutaneous absorption of the two active ingredients, while SLN guaranteed an interesting delayed and sustained release of FITO. In vivo evaluation showed clearly that the formulation containing both the actives (NA and FITO) is able to recover about 95% of skin barrier integrity eight days after tape stripping. This effect is probably due to the "synergistic effect" of NA and FITO.

  16. Modelling millimetre wave propagation and absorption in a high resolution skin model: the effect of sweat glands

    Energy Technology Data Exchange (ETDEWEB)

    Shafirstein, Gal [Department of Otolaryngology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, 543, Little Rock, AR 72205 (United States); Moros, Eduardo G, E-mail: [Division of Radiation Physics and Informatics, Department of Radiation Oncology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham, 771, Little Rock, AR 72205 (United States)


    The aim of this work was to investigate the potential effect of sweat gland ducts (SGD) on specific absorption rate (SAR) and temperature distributions during mm-wave irradiation. High resolution electromagnetic and bio-heat transfer models of human skin with SGD were developed using a commercially available simulation software package (SEMCAD X(TM)). The skin model consisted of a 30 {mu}m stratum corneum, 350 {mu}m epidermis and papillary dermis (EPD) and 1000 {mu}m dermis. Five SGD of 60 {mu}m radius and 300 {mu}m height were embedded linearly with 370 {mu}m separation. A WR-10 waveguide positioned 20 {mu}m from the skin surface and delivering 94 GHz electromagnetic radiation was included in the model. Saline conductivity was assigned inside SGD. SAR and temperatures were computed with and without SGD. Despite their small scale, SAR was significantly higher within SGD than in the EPD without SGD. Without SGD, SAR and temperature maxima were in the dermis near EPD. With SGD, SAR maximum was inside SGD while temperature maximum moved to the EPD/stratum-corneum junction. Since the EPD participates actively in perception, the effect of SGD should be taken into account in nociceptive studies involving mm-waves. This research represents a significant step towards higher spatial resolution numerical modelling of the skin and shows that microstructures can play a significant role in mm-wave absorption and induced temperature distributions.

  17. Modelling millimetre wave propagation and absorption in a high resolution skin model: the effect of sweat glands (United States)

    Shafirstein, Gal; Moros, Eduardo G.


    The aim of this work was to investigate the potential effect of sweat gland ducts (SGD) on specific absorption rate (SAR) and temperature distributions during mm-wave irradiation. High resolution electromagnetic and bio-heat transfer models of human skin with SGD were developed using a commercially available simulation software package (SEMCAD X™). The skin model consisted of a 30 µm stratum corneum, 350 µm epidermis and papillary dermis (EPD) and 1000 µm dermis. Five SGD of 60 µm radius and 300 µm height were embedded linearly with 370 µm separation. A WR-10 waveguide positioned 20 µm from the skin surface and delivering 94 GHz electromagnetic radiation was included in the model. Saline conductivity was assigned inside SGD. SAR and temperatures were computed with and without SGD. Despite their small scale, SAR was significantly higher within SGD than in the EPD without SGD. Without SGD, SAR and temperature maxima were in the dermis near EPD. With SGD, SAR maximum was inside SGD while temperature maximum moved to the EPD/stratum-corneum junction. Since the EPD participates actively in perception, the effect of SGD should be taken into account in nociceptive studies involving mm-waves. This research represents a significant step towards higher spatial resolution numerical modelling of the skin and shows that microstructures can play a significant role in mm-wave absorption and induced temperature distributions.

  18. Foresight into a new transdermal absorption study of cosmetics: how to evaluate transdermal absorption and skin concentration of cosmetics?


    杉林, 堅次; 押坂, 勇志; 藤堂, 浩明


    Skin permeation experiments have been broadly done since 1970s to 80s as an evaluation method for transdermal drug delivery systems.In cosmetic formulations,skin concentration of active ingredients is more important than their skin permeation,because primary target site of the active ingredients is skin surface or skin tissues.Nevertheless,little investigation was carried out on the test method of skin concentration after application of cosmetic formulations. Recently we investigated an estim...

  19. In vivo skin absorption and distribution of the nerve agent VX (O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate) in the domestic white pig. (United States)

    Chilcott, R P; Dalton, C H; Hill, I; Davison, C M; Blohm, K L; Clarkson, E D; Hamilton, M G


    The purpose of this study was to characterize the skin absorption and distribution of VX (O-ethyl-S-[2 (diisopropylamino)ethyl] methylphosphonothioate) in the domestic pig in order to evaluate the animal as a potential model for assessing pretreatments against toxic anti-cholinesterase compounds. A liquid droplet (equivalent to a 2 x LD50 dose) of radiolabelled VX was applied to the inner ear-skin of each anaesthetized animal. Blood and tissue samples (liver, lung, kidney, heart and skin exposure sites) were obtained post-mortem. The amount of radioactivity in each sample was measured by liquid scintillation counting, from which the skin absorption rate and dose distribution of VX were calculated. A substantial proportion (22 +/- 3%) of the applied dose remained within the skin at the site of application. It is conceivable that strategies to minimize or remove this reservoir may be of benefit in the early treatment of VX-exposed casualties. Image analysis of autoradiographs of exposed skin sites indicated that each milligram of radioactive VX covered an area of 1.2 +/- 0.5 cm2. The average skin absorption rate of 14C-VX was 661 +/- 126 microg/cm2 per hour. Comparison of these data with previous studies suggests that human skin is less permeable to VX than pig skin, but VX spreads over a greater surface area when applied to human skin. Thus, paradoxically, while pig-ear skin is more permeable than human skin, the difference in skin surface spreading may lead to the absorption of an equivalent systemic dose.

  20. Percutaneous absorption of estradiol and progesterone in normal and appendage-free skin of the hairless rat: lack of importance of nutritional blood flow. (United States)

    Hueber, F; Besnard, M; Schaefer, H; Wepierre, J


    Percutaneous absorption occurs after passive diffusion through the different layers of the skin and its appendages. Thereafter, a resorption process into the cutaneous microcirculation brings the compounds into the systemic circulation. The objective of this in vivo study in the hairless rat was to compare the percutaneous absorption of two steroids on normal and appendage-free (scar) skin and to show if differences in absorption result only from the lack of hair follicles and sebaceous glands and/or from a modification of local blood flow. Percutaneous absorption was evaluated with estradiol and progesterone after 30 min, 2 and 6 h. Except after 30 min, the reservoir function of the stratum corneum of scar skin was approximately twice as high as in normal skin. Eighty to ninety percent of the estradiol and progesterone found in the stratum corneum were located in its superficial layers. Inversely, whatever the application time was, the concentrations of both steroids in the epidermis and dermis were significantly higher in normal skin than in scar skin with maximal difference between about 40 and 400 microns, the area of sebaceous gland localization. Cutaneous blood flow in full-thickness skin, assessed by the thallium-201 method, was globally identical in normal and in scar skin. In scar skin, at the level of papillary dermis, a decrease in blood flow due to the thicker viable epidermis and the flat dermoepidermal junction has been shown without implying an accumulation of drug in the epidermis and superficial dermis. Under these conditions, our results clearly demonstrate that the nutritional blood flow does not interfere with the percutaneous absorption of estradiol and progesterone in normal and scar skin. Thus, they confirm the significant contribution of hair follicles and sebaceous glands to drug penetration into the skin and subsequently the systemic circulation.

  1. Extrapolation of systemic bioavailability assessing skin absorption and epidermal and hepatic metabolism of aromatic amine hair dyes in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Manwaring, John, E-mail: [Procter & Gamble Inc., Mason Business Center, Mason, OH 45040 (United States); Rothe, Helga [Procter & Gamble Service GmbH, Sulzbacher Str. 40, 65823 Schwalbach am Taunus (Germany); Obringer, Cindy; Foltz, David J.; Baker, Timothy R.; Troutman, John A. [Procter & Gamble Inc., Mason Business Center, Mason, OH 45040 (United States); Hewitt, Nicola J. [SWS, Erzhausen (Germany); Goebel, Carsten [Procter & Gamble Service GmbH, Sulzbacher Str. 40, 65823 Schwalbach am Taunus (Germany)


    Approaches to assess the role of absorption, metabolism and excretion of cosmetic ingredients that are based on the integration of different in vitro data are important for their safety assessment, specifically as it offers an opportunity to refine that safety assessment. In order to estimate systemic exposure (AUC) to aromatic amine hair dyes following typical product application conditions, skin penetration and epidermal and systemic metabolic conversion of the parent compound was assessed in human skin explants and human keratinocyte (HaCaT) and hepatocyte cultures. To estimate the amount of the aromatic amine that can reach the general circulation unchanged after passage through the skin the following toxicokinetically relevant parameters were applied: a) Michaelis–Menten kinetics to quantify the epidermal metabolism; b) the estimated keratinocyte cell abundance in the viable epidermis; c) the skin penetration rate; d) the calculated Mean Residence Time in the viable epidermis; e) the viable epidermis thickness and f) the skin permeability coefficient. In a next step, in vitro hepatocyte K{sub m} and V{sub max} values and whole liver mass and cell abundance were used to calculate the scaled intrinsic clearance, which was combined with liver blood flow and fraction of compound unbound in the blood to give hepatic clearance. The systemic exposure in the general circulation (AUC) was extrapolated using internal dose and hepatic clearance, and C{sub max} was extrapolated (conservative overestimation) using internal dose and volume of distribution, indicating that appropriate toxicokinetic information can be generated based solely on in vitro data. For the hair dye, p-phenylenediamine, these data were found to be in the same order of magnitude as those published for human volunteers. - Highlights: • An entirely in silico/in vitro approach to predict in vivo exposure to dermally applied hair dyes • Skin penetration and epidermal conversion assessed in human

  2. Evaluation of 3D-human skin equivalents for assessment of human dermal absorption of some brominated flame retardants. (United States)

    Abdallah, Mohamed Abou-Elwafa; Pawar, Gopal; Harrad, Stuart


    Ethical and technical difficulties inherent to studies in human tissues are impeding assessment of the dermal bioavailability of brominated flame retardants (BFRs). This is further complicated by increasing restrictions on the use of animals in toxicity testing, and the uncertainties associated with extrapolating data from animal studies to humans due to inter-species variations. To overcome these difficulties, we evaluate 3D-human skin equivalents (3D-HSE) as a novel in vitro alternative to human and animal testing for assessment of dermal absorption of BFRs. The percutaneous penetration of hexabromocyclododecanes (HBCD) and tetrabromobisphenol-A (TBBP-A) through two commercially available 3D-HSE models was studied and compared to data obtained for human ex vivo skin according to a standard protocol. No statistically significant differences were observed between the results obtained using 3D-HSE and human ex vivo skin at two exposure levels. The absorbed dose was low (less than 7%) and was significantly correlated with log Kow of the tested BFR. Permeability coefficient values showed increasing dermal resistance to the penetration of γ-HBCD>β-HBCD>α-HBCD>TBBPA. The estimated long lag times (>30 min) suggests that frequent hand washing may reduce human exposure to HBCDs and TBBPA via dermal contact.

  3. Effects of polarization and absorption on laser induced optical breakdown threshold for skin rejuvenation (United States)

    Varghese, Babu; Bonito, Valentina; Turco, Simona; Verhagen, Rieko


    Laser induced optical breakdown (LIOB) is a non-linear absorption process leading to plasma formation at locations where the threshold irradiance for breakdown is surpassed. In this paper we experimentally demonstrate the influence of polarization and absorption on laser induced breakdown threshold in transparent, absorbing and scattering phantoms made from water suspensions of polystyrene microspheres. We demonstrate that radially polarized light yields a lower irradiance threshold for creating optical breakdown compared to linearly polarized light. We also demonstrate that the thermal initiation pathway used for generating seed electrons results in a lower irradiance threshold compared to multiphoton initiation pathway used for optical breakdown.

  4. Absorption and metabolism of triclosan after application to the skin of B6C3F1 mice. (United States)

    Fang, Jia-Long; Vanlandingham, Michelle; da Costa, Gonçalo Gamboa; Beland, Frederick A


    Triclosan is used as an antimicrobial agent in personal care products, household items, medical devices, and clinical settings. Humans can receive lifelong exposures to triclosan; however, data on the toxicity and carcinogenicity after topical application are lacking. This study determined the absorption, distribution, metabolism, and excretion of triclosan after application to the skin of B6C3F1 mice. [(14)C(U)]triclosan (10 or 100 mg triclosan/kg body weight) was administered topically to mice in two separate experiments: a vehicle selection experiment using propylene glycol, ethanol, and a generic cosmetic cream, and a toxicokinetic experiment. Mice were killed up to 72 h after triclosan administration, and excreta and tissues were analyzed for radioactivity. Ethanol had the best properties of the vehicles evaluated. Maximum absorption was obtained at approximately 12 h after dosing. Radioactivity appeared in the excreta and in all tissues examined, with the highest levels in the gall bladder and the lowest levels in the brain. Triclosan was metabolized to triclosan sulfate, triclosan glucuronide, 2,4-dichlorophenol, and hydroxytriclosan. The metabolite profile was tissue-dependent and the predominant route of excretion was fecal. The AUC(0-∞) and the Cmax of plasma and liver in females were greater than those in males. Slightly lower absorption was observed in mice with Elizabethan collars.

  5. A new Monte Carlo code for absorption simulation of laser-skin tissue interaction

    Institute of Scientific and Technical Information of China (English)

    Afshan Shirkavand; Saeed Sarkar; Marjaneh Hejazi; Leila Ataie-Fashtami; Mohammad Reza Alinaghizadeh


    In laser clinical applications, the process of photon absorption and thermal energy diffusion in the target tissue and its surrounding tissue during laser irradiation are crucial. Such information allows the selection of proper operating parameters such as laser power, and exposure time for optimal therapeutic. The Monte Carlo method is a useful tool for studying laser-tissue interaction and simulation of energy absorption in tissue during laser irradiation. We use the principles of this technique and write a new code with MATLAB 6.5, and then validate it against Monte Carlo multi layer (MCML) code. The new code is proved to be with good accuracy. It can be used to calculate the total power bsorbed in the region of interest. This can be combined for heat modelling with other computerized programs.

  6. Noninvasive determination of absorption coefficient and reduced scattering coefficient of human skin tissues in vivo with oblique-incidence reflectometry

    Institute of Scientific and Technical Information of China (English)

    Ping Sun; Yu Wang; Xiaoli Mo; Jinghui Xie


    A spatial distribution of diffuse reflectance produced by obliquely incident light is not centered about the point of light entry. The value of shift in the center of diffuse reflectance is directly related to the absorption coefficient μa and the effective attenuation coefficient μeff. μa and the reduced scattering coefficient μ's of human skin tissues in vivo are measured by oblique-incidence reflectometry based on the two-source diffuse theory model. For ten Chinese volunteers aged 15-63 years, μa and μ's are noninvasively determined to be 0.029 - 0.075 and 0.52 - 0.97 mm-1, respectively.

  7. The effects of heat on skin barrier function and in vivo dermal absorption. (United States)

    Oliveira, Gabriela; Leverett, Jesse C; Emamzadeh, Mandana; Lane, Majella E


    Enhanced delivery of ingredients across the stratum corneum (SC) is of great interest for improving the efficacy of topically applied formulations. Various methods for improving dermal penetration have been reported including galvanic devices and micro-needles. From a safety perspective it is important that such approaches do not compromise SC barrier function. This study investigates the influence of topically applied heat in vivo on the dermal uptake and penetration of a model active, allantoin from gel and lotion formulations. A custom designed device was used to deliver 42°C for 30s daily to human subjects after application of two formulations containing allantoin. The results were compared with sites treated with formulations containing no active and no heat, and a control site. In addition to penetration of allantoin, the integrity of the SC was monitored using trans-epidermal water loss (TEWL) measurements. The results showed that just 30s of 42°C topically applied heat was enough to cause significantly more penetration of allantoin from the lotion formulation compared with no application of heat. TEWL data indicated that the integrity of the skin was not compromised by the treatment. However, the application of heat did not promote enhanced penetration of the active from the gel formulation. Vehicle composition is therefore an important factor when considering thermal enhancement strategies for targeting actives to the skin.

  8. Human systemic exposure to a [14C]-para-phenylenediamine- containing oxidative hair dye and correlation with in vitro percutaneous absorption in human or pig skin

    NARCIS (Netherlands)

    Hueber-Becker, F.; Nohynek, G.J.; Meuling, W.J.A.; Benech-Kieffer, F.; Toutain, H.


    We investigated the absorption of a commercial [14C]-PPD- containing oxidative dark-shade hair dye in human volunteers as well as in vitro using human or pig ear skin. The hair of eight male volunteers was cut to a standard length, dyed, washed, dried, clipped and collected. Hair, washing water, mat

  9. Absorption of ethanol, acetone, benzene and 1,2-dichloroethane through human skin in vitro: a test of diffusion model predictions. (United States)

    Gajjar, Rachna M; Kasting, Gerald B


    The overall goal of this research was to further develop and improve an existing skin diffusion model by experimentally confirming the predicted absorption rates of topically-applied volatile organic compounds (VOCs) based on their physicochemical properties, the skin surface temperature, and the wind velocity. In vitro human skin permeation of two hydrophilic solvents (acetone and ethanol) and two lipophilic solvents (benzene and 1,2-dichloroethane) was studied in Franz cells placed in a fume hood. Four doses of each (14)C-radiolabed compound were tested - 5, 10, 20, and 40μLcm(-2), corresponding to specific doses ranging in mass from 5.0 to 63mgcm(-2). The maximum percentage of radiolabel absorbed into the receptor solutions for all test conditions was 0.3%. Although the absolute absorption of each solvent increased with dose, percentage absorption decreased. This decrease was consistent with the concept of a stratum corneum deposition region, which traps small amounts of solvent in the upper skin layers, decreasing the evaporation rate. The diffusion model satisfactorily described the cumulative absorption of ethanol; however, values for the other VOCs were underpredicted in a manner related to their ability to disrupt or solubilize skin lipids. In order to more closely describe the permeation data, significant increases in the stratum corneum/water partition coefficients, Ksc, and modest changes to the diffusion coefficients, Dsc, were required. The analysis provided strong evidence for both skin swelling and barrier disruption by VOCs, even by the minute amounts absorbed under these in vitro test conditions.

  10. Skin absorption studies of octyl-methoxycinnamate loaded poly(D,L-lactide) nanoparticles: estimation of the UV filter distribution and release behaviour in skin layers. (United States)

    Vettor, M; Bourgeois, S; Fessi, H; Pelletier, J; Perugini, P; Pavanetto, F; Bolzinger, M A


    New formulation strategies have to be developed to limit the skin penetration of UV-filter. Nanoparticles (NP) are very suitable for that purpose. In this study, the skin distribution, at different times (1, 2 and 3 h), of octyl-methoxycinnamate (OMC) from loaded PLA-nanoparticles was compared to a classical formulation containing non-encapsulated OMC, using the Franz cell method. The results showed that the OMC penetration was clearly impeded by stratum corneum and that the major part of the OMC-NP was accumulated at the skin surface (> 80%). A significant lower OMC amount was quantified in viable skin with NP compared to the OMC emulgel. To accurately determine the real OMC amount in close contact with viable skin layers two solvents were used to extract OMC from the skin compartments. Acetone (ACET) allowed quantifying both OMC in NP and OMC released from the particles, while isopropylmyristate (IPM), a non-solvent of the NP polymer (PLA), allowed quantifying only OMC released from the particles. Using IPM as an extraction solvent, it appeared that the OMC released from NP, in contact with viable skin, was 3-fold lower than free OMC diffused from the emulgel. Lastly, a sustained release was observed when nanoparticles were used.

  11. Efficacy of skin wash on dermal absorption: an in vitro study on four model compounds of varying solubility

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo


    that percutaneous penetration continues after end of exposure due to the reservoir present in the skin. However, penetration rate will decrease significantly, and it is evident that simple hand-wash after end of exposure not only reduces the amount of residue present in the upper skin compartment but also......PURPOSE: Following dermal exposure to chemicals causing systemic toxicity, the general advice to avoid further systemic exposure is to wash the skin. The present study uses four model compounds (benzoic acid, glyphosat, caffeine, malathion) with varying size and solubility to substantiate...... this advice and quantify the effect of skin wash following 6 h dermal exposure on subsequent extent of skin penetration and deposition within the skin compartment. METHOD: Percutaneous penetration through human skin is studied in an in vitro model with static diffusion cells. RESULTS: The study demonstrates...

  12. Percutaneous Absorption of Salicylic Acid after Administration of Trolamine Salicylate Cream in Rats with Transcutol® and Eucalyptus Oil Pre-Treated Skin

    Directory of Open Access Journals (Sweden)

    Paniz Sajjadi


    Full Text Available Purpose: This study was conducted to assess the effect of skin pre-treatment with Transcutol® and eucalyptus oil on systemic absorption of topical trolamine salicylate in rat. Methods: Pharmacokinetic parameters of salicylic acid following administration of trolamine salicylate on rat skin pre-treated with either Transcutol® or eucalyptus oil were determined using both non-compartmental and non-linear mixed effect modeling approaches and compared with those of control group. Results: Median (% of interquartile range/median of salicylic acid AUC0-8hr (ng/mL/hr values in Transcutol® or eucalyptus oil treated rats were 2522(139% and 58976(141%, respectively as compared to the 3023(327% of the control group. Skin pre-treatment with eucalyptus oil could significantly decrease extravascular volume of distribution (V/F and elimination rate constant (k of salicylic acid. Conclusion: Unlike Transcutol®, eucalyptus oil lead to enhanced transdermal absorption of trolamine salicylate through rat skin.

  13. Prediction of formulation effects on dermal absorption of topically applied ectoparasiticides dosed in vitro on canine and porcine skin using a mixture-adjusted quantitative structure permeability relationship. (United States)

    Riviere, J E; Brooks, J D; Collard, W T; Deng, J; de Rose, G; Mahabir, S P; Merritt, D A; Marchiondo, A A


    Topical application of ectoparasiticides for flea and tick control is a major focus for product development in animal health. The objective of this work was to develop a quantitative structure permeability relationship (QSPeR) model sensitive to formulation effects for predicting absorption and skin deposition of five topically applied drugs administered in six vehicle combinations to porcine and canine skin in vitro. Saturated solutions (20 μL) of (14) C-labeled demiditraz, fipronil, permethrin, imidacloprid, or sisapronil were administered in single or binary (50:50 v/v) combinations of water, ethanol, and transcutol (6 formulations, n = 4-5 replicates per treatment) nonoccluded to 0.64 cm(2) disks of dermatomed pig or dog skin mounted in flow-through diffusion cells. Perfusate flux over 24 h and skin deposition at termination were determined. Permeability (logKp), absorption, and penetration endpoints were modeled using a four-term Abrahams and Martin (hydrogen-bond donor acidity and basicity, dipolarity/polarizability, and excess molar refractivity) linear free energy QSPeR equation with a mixture factor added to compensate for formulation ingredient interactions. Goodness of fit was judged by r(2) , cross-validation coefficient, coefficients (q(2) s), and Williams Plot to visualize the applicability domain. Formulation composition was the primary determinant of permeation. Compounds generally penetrated dog skin better than porcine skin. The vast majority of permeated penetrant was deposited within the dosed skin relative to transdermal flux, an attribute for ectoparasiticides. The best QSPeR logKp model for pig skin permeation (r(2) = 0.86, q(2) s = 0.85) included log octanol/water partition coefficient as the mixture factor, while for dogs (r(2) = 0.91, q(2) s = 0.90), it was log water solubility. These studies clearly showed that the permeation of topical ectoparasiticides could be well predicted using QSPeR models that account for both the physical

  14. Effect of vehicles and penetration enhancers on the in vitro percutaneous absorption of tenoxicam through hairless mouse skin. (United States)

    Gwak, Hye Sun; Chun, In Koo


    The effects of vehicles and penetration enhancers on the in vitro permeation of tenoxicam from saturated solutions through dorsal hairless mouse skin were investigated. Various types of vehicles, including ester-, alcohol-, and ether-types and their mixtures, were used as vehicles, and then a series of fatty acids and amines were employed as enhancers, respectively. Even though the fluxes of tenoxicam from saturated pure vehicles were generally low (0.1-1.1 microg/cm2 per h), the skin permeability of tenoxicam was significantly increased by the combination of diethylene glycol monoethyl ether (DGME) and propylene glycol monolaurate (PGML) or propylene glycol monocaprylate (PGMC); the highest fluxes were achieved at 40% of DGME in both of the two cosolvents. The marked synergistic enhancement was also obtained by using propylene glycol (PG)-oleyl alcohol (OAl) cosolvent. The greatest flux was attained by the addition of unsaturated fatty acids at 3% concentration to PG. But saturated fatty acids failed to show a significant enhancing effect. The enhancement factors with the addition of oleic acid (OA) or linoleic acid (LOA) to PG were 348 and 238, respectively. Tromethamine (TM) showed an enhancing effect by the increased solubility; however, triethanolamine (TEA) did not show a significant enhancing effect. Rather, it decreased the fluxes of tenoxicam when added to PG with fatty acids. The above results indicate that the combinations of lipophilic vehicles like OA, LOA or OAl and hydrophilic vehicles like PG can be used for enhancing the skin permeation of tenoxicam.

  15. Absorption of bacampicillin and ampicillin and penetration into body fluids (skin blister fluid, saliva, tears) in healthy volunteers. (United States)

    Simon, C; Malerczyk, V; Klaus, M


    Equimolar doses of bacampicillin, which is rapidly converted to ampicillin in the body by hydrolysis, and ampicillin were administered orally, in the case of ampicillin also by intravenous injection, to 10 healthy subjects (cross-over study). Comparison of the areas under the serum concentrations curves after intravenous and oral administration showed that bacampillin was absorbed to 95% and orally given ampicillin to 35%. The mean peak serum levels (Cmax) after 0.8 g of oral bacampicillin were higher (15.9 microgram/ml) and appeared earlier (tmax 60 min) than after 0.556 g of oral ampicillin (3.2 microgram/ml, tmax 150 min). One and three hours after oral administration skin blister fluid contained four times more ampicillin after doses of bacampicillin than after oral ampicillin. One hour after intravenous injection of ampicillin the skin blister concentrations were 20 times higher than after oral administration of this antibiotic and three to four times higher than after oral administration of bacampicillin. The levels in saliva and tears were also determined and showed similar relationships. Since higher peaks serum levels resulted in higher and longer lasting concentrations in the extravascular space, bacampicillin is to be preferred for oral therapy.

  16. In vitro percutaneous absorption of tenoxicam from pressure-sensitive adhesive matrices across the hairless mouse skin. (United States)

    Gwak, H S; Chun, I K


    To investigate the feasibility of developing a new tenoxicam plaster, the effects of vehicles and penetration enhancers on the in vitro permeation of tenoxicam from a pressure-sensitive adhesive (PSA) matrices across the dorsal hairless mouse skin were studied. Vehicles employed in this study were propylene glycol (PG)-oleyl alcohol (OAI), PG-oleic acid (OA), and diethylene glycol monoethyl ether (DGME)-propylene glycol monolaurate (PGML) cosolvents with/without fatty acids. In this study, amines such as triethanolamine (TEA) and tromethamine (TM) were additionally used as a solubilizer. Among PSAs used, Duro-Tak 87-2510 showed much higher release rate than either Duro-Tak 87-2100 or Duro-Tak 87-2196. The relatively high flux rate was obtained with the formulation of DGME-PGML (40:60, v/v) with 3% OA and 5% TM, and the flux increased as a function of the dose; the initial flux up to 12 h was 4.98 +/- 1.38 microg/cm2/h at the tenoxicam dose of 50 mg/70 cm2. This flux was much higher than that of a commercial piroxicam patch (Trast) (1.24 +/- 0.73 microg/ cm2/hr) with almost only one-third that of the commercial patch. Therefore, these observations indicated that these composition of tenoxicam plaster may be practically applicable.

  17. Nanostructured lipid carriers-based flurbiprofen gel after topical administration: acute skin irritation, pharmacodynamics, and percutaneous absorption mechanism. (United States)

    Song, Aihua; Su, Zhen; Li, Sanming; Han, Fei


    In order to assess the preliminary safety and effectiveness of nanostructured lipid carriers-based flurbiprofen gel (FP NLC-gel), the acute irritation test, in vivo pharmacodynamics evaluation and pharmacokinetic study were investigated after topical application. No dropsy and erythema were observed after continuous dosing 7 d of FP NLC-gel on the rabbit skin, and the xylene-induced ear drossy could be inhibited by FP NLC-gel at different dosages. The maximum concentration of FP in rats muscle was 2.03 μg/g and 1.55 μg/g after oral and topical administration, respectively. While the peak concentration in untreated muscle after topical administration was only 0.37 μg/mL. And at any time, following topical administration the mean muscle-plasma concentration ratio Cmuscle/CPlasma was obviously higher than that following oral administration. Results indicated that FP could directly penetrate into the subcutaneous muscle tissue from the administration site. Thus, the developed FP NLC-gel could be a safe and effective vehicle for topical delivery of FP.

  18. New formulation of chemical peeling agent: 30% salicylic acid in polyethylene glycol. Absorption and distribution of 14C-salicylic acid in polyethylene glycol applied topically to skin of hairless mice. (United States)

    Ueda, Setsuko; Mitsugi, Koichi; Ichige, Kazumi; Yoshida, Kenji; Sakuma, Tomoko; Ninomiya, Shin-ichi; Sudou, Tetsuji


    Salicylic acid is used in chemical peeling procedures. However, they have caused many side effects, even salicylism. To achieve a salicylic acid peeling that would be safer for topical use, we recently developed a new formulation consisting of 30% salicylic acid in polyethylene glycol (PEG) vehicle. In an extension of our previous research, we studied the absorption of 30% salicylic acid labeled with 14C in PEG vehicle applied topically to the intact and damaged skin of male hairless mice. An ointment containing 3 mg salicylic acid in 10 mg vehicle was applied to both groups. In animals with intact skin, 1 h after application the plasma concentration of radioactivity was 1665.1 ng eq/ml, significantly lower than the 21437.6 ng eq/ml observed in mice with damaged skin. Microautoradiograms of intact skin showed that the level of radioactivity in the cornified cell layer was similar at 6 h after application. However, in damaged skin, the overall level of radioactivity showed a decrease by 3 h after application. In the carcasses remaining after the treated intact and damaged skin had been removed, 0.09 and 11.38% of the applied radioactivity remained, respectively. These findings confirm that 30% salicylic acid in PEG vehicle is little absorbed through the intact skin of hairless mice, and suggest that salicylism related to absorption through the skin of quantities of topically applied salicylic acid is not likely to occur in humans with intact skin during chemical peeling with this preparation. This new preparation of 30% salicylic acid in PEG vehicle is believed to be safe for application as a chemical peeling agent.

  19. Anti-HepG-2 Cell Properties of Rare Earth Tungstosilicic Polyoxometalates Containing 5-Fluorouracil%The Study of Absorption Efficiency and Restoring Effects of Collagen and Ascorbic Acid on Aged Skin by Fluorescence and Reflection Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    LIU Xia; WANG Shuai-shuai; FENG Chang-gen


    Collagen is one of the main structural proteins in human dermis. The lack and atrophy of collagen induces the appearance of wrinkles and beginning of aging. L-ascorbic acid has significant effects on skin-whitening and anti-oxidation, which helps keep skin beautiful and healthy, respectively. With auto-fluorescence, the amount of collagen is in proportion to the strength of its fluorescence spectrum. Therefore, a new method is proposed to determine the content of collagen and the health of skin through the analysis of fluorescence and reflection spectra. Compared with conventional chemical analysis, this method needs less time, and is much more noninvasive. Solutions of different concentration of external collagen and L-ascorbic acid were applied on healthy, spotted and wrinkled skin in this study. By the time dependence of fluorescence and reflection spectra, the effects of skin absorption and restoration of collagen and L-ascorbic acid were derived, respectively. The experiment shows that the collagen or L-ascorbic acid solution of adequate concentration is best for skin absorption. Admixed with suitable concentration of L-ascorbic acid, the collagen solution was well absorbed and results in effect of smoothing wrinkles; the effect of L-ascorbic acid to clear up the spots was also demonstrated. By scientific explorations shown above, the restoration effects of cosmetic materials were validated, and people's confusion and myth about skincare products were avoided. Consequently, this study helps advance cosmetic industry.

  20. Silver percutaneous absorption after exposure to silver nanoparticles: a comparison study of three human skin graft samples used for clinical applications. (United States)

    Bianco, C; Adami, G; Crosera, M; Larese, F; Casarin, S; Castagnoli, C; Stella, M; Maina, G


    Silver nanoparticles (AgNPs) are increasingly applied to a wide range of materials for biomedical use. These enable a close contact with human skin, thanks to the large release of silver ions that is responsible for a broad spectrum of antimicrobial activity. Silver can permeate the skin; however, there are no data available on silver permeation through skin grafts commonly used in burns recovery. The aim of our study was to evaluate silver penetration using fresh, cryopreserved, and glycerolized human skin grafts after exposure to a suspension of AgNPs in synthetic sweat using a Franz diffusion cell apparatus for 24 h. Silver permeation profiles revealed a significantly higher permeation through glycerolized skin compared with both fresh and cryopreserved skin: 24-h silver flux penetration was 0.2 ng cm(-2) h(-1) (lag time: 8.2 h) for fresh skin, 0.3 ng cm(-2) h(-1) (lag time: 10.9 h) for cryopreserved skin, and 3.8 ng cm(-2) h(-1) (lag time: 6.3 h) for glycerolized skin. Permeation through glycerolized skin is significantly higher compared to both fresh and cryopreserved skin. This result can generate relevant clinical implications for burns treatment with products containing AgNPs.

  1. Correlation of skin blanching and percutaneous absorption for glucocorticoid receptor agonists by matrix-assisted laser desorption ionization mass spectrometry imaging and liquid extraction surface analysis with nanoelectrospray ionization mass spectrometry. (United States)

    Marshall, Peter; Toteu-Djomte, Valerie; Bareille, Philippe; Perry, Hayley; Brown, Gillian; Baumert, Mark; Biggadike, Keith


    Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) and liquid extraction surface analysis (LESA) with nanoelectrospray ionization mass spectrometry (nESI-MS) have both been successfully employed to determine the degree of percutaneous absorption of three novel nonsteroid glucocorticoid receptor (GR) agonists in porcine ear sections. Historically, the ability of a glucocorticoid to elicit a skin blanching response when applied at low dose in ethanol solution to the forearms of healthy human volunteers has been a reliable predictor of their topical anti-inflammatory activity. While all three nonsteroidal GR agonists under investigation caused a skin blanching effect, the responses did not correlate with in vitro GR agonist potencies and different time courses were also observed for the skin blanching responses. MALDI MSI and LESA with nESI-MS were used to investigate and understand these different responses. The findings of the investigation was that the depth of porcine skin penetration correlates to the degree of skin blanching obtained for the same three compounds in human volunteers.

  2. Skin Diseases: Skin Health and Skin Diseases (United States)

    Skip Navigation Bar Home Current Issue Past Issues Skin Diseases Skin Health and Skin Diseases Past Issues / Fall 2008 Table of Contents ... acne to wrinkles Did you know that your skin is the largest organ of your body? It ...

  3. Development of a nanogel formulation for transdermal delivery of tenoxicam: a pharmacokinetic-pharmacodynamic modeling approach for quantitative prediction of skin absorption. (United States)

    Elkomy, Mohammed H; El Menshawe, Shahira F; Eid, Hussein M; Ali, Ahmed M A


    This study investigates potentials of solid lipid nanoparticles (SLN)-based gel for transdermal delivery of tenoxicam (TNX) and describes a pharmacokinetic-pharmacodynamic (PK-PD) modeling approach for predicting concentration-time profile in skin. A 2(3) factorial design was adopted to study the effect of formulation factors on SLN properties and determine the optimal formulation. SLN-gel tolerability was investigated using rabbit skin irritation test. Its anti-inflammatory activity was assessed by carrageenan-induced rat paw edema test. A published Hill model for in vitro inhibition of COX-2 enzyme was fitted to edema inhibition data. Concentration in skin was represented as a linear spline function and coefficients were estimated using non-linear regression. Uncertainty in predicted concentrations was assessed using Monte Carlo simulations. The optimized SLN was spherical vesicles (58.1 ± 3.1 nm) with adequate entrapment efficiency (69.6 ± 2.6%). The SLN-gel formulation was well-tolerated. It increased TNX activity and skin level by 40 ± 13.5, and 227 ± 116%, respectively. Average Cmax and AUC0-24 predicted by the model were 2- and 3.6-folds higher than the corresponding values computed using in vitro permeability data. SLN-gel is a safe and efficient carrier for TNX across skin in the treatment of inflammatory disorders. PK-PD modeling is a promising approach for indirect quantitation of skin deposition from PD activity data.

  4. Your Skin (United States)

    ... Room? What Happens in the Operating Room? Your Skin KidsHealth > For Kids > Your Skin Print A A ... are really dead skin cells. continue Bye-Bye Skin Cells These old cells are tough and strong, ...

  5. Skin Conditions (United States)

    Your skin is your body's largest organ. It covers and protects your body. Your skin Holds body fluids in, preventing dehydration Keeps harmful ... it Anything that irritates, clogs, or inflames your skin can cause symptoms such as redness, swelling, burning, ...

  6. Study of surfactant-skin interactions by skin impedance measurements. (United States)

    Lu, Guojin; Moore, David J


    The stratum corneum (SC) plays a very critical physiological role as skin barrier in regulating water loss through the skin and protects the body from a wide range of physical and chemical exogenous insults. Surfactant-containing formulations can induce skin damage and irritation owing to surfactant absorption and penetration. It is generally accepted that reduction in skin barrier properties occurs only after surfactants have penetrated/permeated into the skin barrier. To mitigate the harshness of surfactant-based cleansing products, penetration/permeation of surfactants should be reduced. Skin impedance measurements have been taken in vitro on porcine skin using vertical Franz diffusion cells to investigate the impact of surfactants, temperature and pH on skin barrier integrity. These skin impedance results demonstrate excellent correlation with other published methods for assessing skin damage and irritation from different surfactant chemistry, concentration, pH, time of exposure and temperature. This study demonstrates that skin impedance can be utilized as a routine approach to screen surfactant-containing formulations for their propensity to compromise the skin barrier and hence likely lead to skin irritation.

  7. Skin Infections (United States)

    ... Old Feeding Your 8- to 12-Month-Old Feeding Your 1- to 2-Year-Old First Aid: Skin ... (bacterial infection of the deeper layers of the skin and tissues beneath) are typical childhood skin infections. The usual bacterial culprits in skin ...

  8. Skin Biomes. (United States)

    Fyhrquist, N; Salava, A; Auvinen, P; Lauerma, A


    The cutaneous microbiome has been investigated broadly in recent years and some traditional perspectives are beginning to change. A diverse microbiome exists on human skin and has a potential to influence pathogenic microbes and modulate the course of skin disorders, e.g. atopic dermatitis. In addition to the known dysfunctions in barrier function of the skin and immunologic disturbances, evidence is rising that frequent skin disorders, e.g. atopic dermatitis, might be connected to a dysbiosis of the microbial community and changes in the skin microbiome. As a future perspective, examining the skin microbiome could be seen as a potential new diagnostic and therapeutic target in inflammatory skin disorders.

  9. Skin Cancer (United States)

    ... are round and lie directly under squamous cells. Melanocytes are specialized skin cells that produce pigment called melanin. The melanin pigment produced by melanocytes gives skin its color. It also protects the ...

  10. Skin Cancer (United States)

    ... the head, face, neck, hands, and arms. Another type of skin cancer, melanoma, is more dangerous but less common. Anyone ... cancer is found early. If not treated, some types of skin cancer cells can spread to other tissues and organs. ...

  11. Sagging Skin (United States)

    ... Dermatologic Surgery Expertise for the life of your skin (TM) Public Resources Dermatologic Surgery Conditions Treatments and ... learn-more"> 3 million Americans are diagnosed with skin cancer every year Any suspicious new growths or ...

  12. Skin tears. (United States)

    Baranoski, S


    Skin tears are a serious, painful problem for older patients. Find out how your staff can recognize patients at risk, what they can do to prevent skin tears, and how to manage them effectively if they occur.

  13. Skin turgor (United States)

    ... arm or abdomen is checked. The skin is held for a few seconds then released. Skin with ... University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the ...

  14. Skin Aging (United States)

    Your skin changes as you age. You might notice wrinkles, age spots and dryness. Your skin also becomes thinner and loses fat, making it ... heal, too. Sunlight is a major cause of skin aging. You can protect yourself by staying out ...

  15. Your Skin (United States)

    ... your body. Without skin, people's muscles, bones, and organs would be hanging out all over the place. Skin holds everything together. It also: protects our bodies helps keep our bodies at just the right temperature allows us to have the sense of touch Don't Miss Your Epidermis The ...

  16. Oily skin (United States)

    ... keep your skin clean using warm water and soap, or a soapless cleanser. Clean your face with astringent pads if frequent face washing causes irritation. Use only water-based or oil-free cosmetics if you have oily skin. Your ...

  17. Influence of metabolism in skin on dosimetry after topical exposure.



    Metabolism of chemicals occurs in skin and therefore should be taken into account when one determines topical exposure dose. Skin metabolism is difficult to measure in vivo because biological specimens may also contain metabolites from other tissues. Metabolism in skin during percutaneous absorption can be studied with viable skin in flow-through diffusion cells. Several compounds metabolized by microsomal enzymes in skin (benzo[a]pyrene and 7-ethoxycoumarin) penetrated human and hairless gui...

  18. Porcine skin flow-through diffusion cell system. (United States)

    Baynes, R E


    Porcine Skin Flow-Through Diffusion Cell System (Ronald E. Baynes, North Carolina State University, Raleigh, North Carolina). Porcine skin can be used in a diffusion cell apparatus to study the rate and extent of absorption of topically applied chemicals through the skin. Although the skin of a number of animals can be used in this system, that of the pig most closely approximates human skin anatomically and physiologically.

  19. Dermal absorption and toxicological risk assessment

    NARCIS (Netherlands)

    Buist, H.


    Absorption of toxic substances via the skin is an important phenomenon in the assessment of the risk of exposure to these substances. People are exposed to a variety of substances and products via the skin, either directly or indirectly, while at work, at home or in public space. Pesticides, organic

  20. Electrophysiological evidence for an ATP-gated ion channel in the principal cells of the frog skin epithelium

    DEFF Research Database (Denmark)

    Brodin, Birger; Nielsen, Robert


    P2X receptor, Na+ absorption, Short circuit current, Cell potential, Microelectrodes, Frog skin, Cytosolic Ca2+......P2X receptor, Na+ absorption, Short circuit current, Cell potential, Microelectrodes, Frog skin, Cytosolic Ca2+...

  1. Aging skin. (United States)

    Bolognia, J L


    Aging of the skin is a composite of actinic damage, chronologic aging, and hormonal influences. The majority of changes associated with aging, such as wrinkles and solar lentigines ("liver spots"), are due to photoaging and reflect cumulative sun exposure as well as skin pigmentation. Classically, chronologic aging includes those cutaneous changes that occur in non-sun-exposed areas, such as the buttocks, and are observed in both men and women. A clinical example would be soft tissue sagging due to elastic fiber degeneration. In women, investigations into the effect of hormones on aging of the skin have concentrated on estrogens; in men, there have been a limited number of studies on the influence of testosterone. The latter have shown an age-dependent decrease in tissue androgens in pubic skin, but not scrotal or thigh skin. To date, age has not been shown to have an effect on androgen receptor binding, although a decrease in foreskin 5 alpha-reductase activity with increasing age has been described. In fibroblast cultures from foreskins, there have been conflicting results as to whether 5 alpha-reductase activity decreases in an age-dependent manner. Some of the skin changes that have been categorized as secondary to chronologic aging, such as decreased sebaceous gland activity and decreased hair growth, may actually represent a decline in the concentration of tissue androgens with increasing age. The influence of androgens on age-related changes in keratinocyte and fibroblast function remains speculative.

  2. Skin Cancer Prevention (United States)

    ... Genetics of Skin Cancer Skin Cancer Screening Research Skin Cancer Prevention (PDQ®)–Patient Version What is prevention? ... prevent cancer are being studied. General Information About Skin Cancer Key Points Skin cancer is a disease ...

  3. Skin Cancer Screening (United States)

    ... Genetics of Skin Cancer Skin Cancer Screening Research Skin Cancer Screening (PDQ®)–Patient Version What is screening? ... These are called diagnostic tests . General Information About Skin Cancer Key Points Skin cancer is a disease ...

  4. Dry Skin (Xerosis) (United States)

    ... Kids’ zone Video library Find a dermatologist Dry skin Overview Dry, ashy skin: People who had atopic ... often have very dry skin as adults. Dry skin: Overview Also called xerosis Dry skin is common. ...

  5. Influence of metabolism in skin on dosimetry after topical exposure. (United States)

    Bronaugh, R L; Collier, S W; Macpherson, S E; Kraeling, M E


    Metabolism of chemicals occurs in skin and therefore should be taken into account when one determines topical exposure dose. Skin metabolism is difficult to measure in vivo because biological specimens may also contain metabolites from other tissues. Metabolism in skin during percutaneous absorption can be studied with viable skin in flow-through diffusion cells. Several compounds metabolized by microsomal enzymes in skin (benzo[a]pyrene and 7-ethoxycoumarin) penetrated human and hairless guinea pig skin predominantly unmetabolized. However, compounds containing a primary amino group (p-aminobenzoic acid, benzocaine, and azo color reduction products) were substrates for acetyltransferase activity in skin and were substantially metabolized during absorption. A physiologically based pharmacokinetic model has been developed with an input equation, allowing modeling after topical exposure. Plasma concentrations in the hairless guinea pig were accurately predicted for the model compound, benzoic acid, from in vitro absorption, metabolism, and other pharmacokinetic parameters.

  6. Metabolism of skin-absorbed resveratrol into its glucuronized form in mouse skin. (United States)

    Murakami, Itsuo; Chaleckis, Romanas; Pluskal, Tomáš; Ito, Ken; Hori, Kousuke; Ebe, Masahiro; Yanagida, Mitsuhiro; Kondoh, Hiroshi


    Resveratrol (RESV) is a plant polyphenol, which is thought to have beneficial metabolic effects in laboratory animals as well as in humans. Following oral administration, RESV is immediately catabolized, resulting in low bioavailability. This study compared RESV metabolites and their tissue distribution after oral uptake and skin absorption. Metabolomic analysis of various mouse tissues revealed that RESV can be absorbed and metabolized through skin. We detected sulfated and glucuronidated RESV metabolites, as well as dihydroresveratrol. These metabolites are thought to have lower pharmacological activity than RESV. Similar quantities of most RESV metabolites were observed 4 h after oral or skin administration, except that glucuronidated RESV metabolites were more abundant in skin after topical RESV application than after oral administration. This result is consistent with our finding of glucuronidated RESV metabolites in cultured skin cells. RESV applied to mouse ears significantly suppressed inflammation in the TPA inflammation model. The skin absorption route could be a complementary, potent way to achieve therapeutic effects with RESV.

  7. How to improve skin notation

    DEFF Research Database (Denmark)

    Sartorelli, Pietro; Ahlers, Heinz W.; Alanko, Kristiina


    The ICOH Scientific Committee on Occupational and Environmental Dermatoses organized an International Workshop on “Dermal risk assessment at workplace” with the aim of focussing on the different ways of approaching the concept of skin notation (S) for chemicals. The Workshop participants presented...... their ideas on several aspects of S such as the problems related to the absorption through the compromised skin, the different approaches to S and models that can be used as alternatives to S. Participants agreed to produce a position paper with the goal of exploring the actions needed to improve the S system...

  8. Skin Cancer (United States)

    ... you ever get a bad sunburn that caused blisters when you were a child?Does your skin ... Cancer InstituteMelanoma International FoundationAmerican Cancer Society ResourcesDiagnosis and Management of Malignant Melanoma by BG Goldstein, AO Goldstein( ...

  9. Millimeter wave dosimetry of human skin. (United States)

    Alekseev, S I; Radzievsky, A A; Logani, M K; Ziskin, M C


    To identify the mechanisms of biological effects of mm waves it is important to develop accurate methods for evaluating absorption and penetration depth of mm waves in the epidermis and dermis. The main characteristics of mm wave skin dosimetry were calculated using a homogeneous unilayer model and two multilayer models of skin. These characteristics included reflection, power density (PD), penetration depth (delta), and specific absorption rate (SAR). The parameters of the models were found from fitting the models to the experimental data obtained from measurements of mm wave reflection from human skin. The forearm and palm data were used to model the skin with thin and thick stratum corneum (SC), respectively. The thin SC produced little influence on the interaction of mm waves with skin. On the contrary, the thick SC in the palm played the role of a matching layer and significantly reduced reflection. In addition, the palmar skin manifested a broad peak in reflection within the 83-277 GHz range. The viable epidermis plus dermis, containing a large amount of free water, greatly attenuated mm wave energy. Therefore, the deeper fat layer had little effect on the PD and SAR profiles. We observed the appearance of a moderate SAR peak in the therapeutic frequency range (42-62 GHz) within the skin at a depth of 0.3-0.4 mm. Millimeter waves penetrate into the human skin deep enough (delta = 0.65 mm at 42 GHz) to affect most skin structures located in the epidermis and dermis.

  10. Squamous cell skin cancer (United States)

    ... that reflect light more, such as water, sand, concrete, and areas that are painted white. The higher ... - skin - squamous cell; Skin cancer - squamous cell; Nonmelanoma skin cancer - squamous ...

  11. Filaggrin and Skin Barrier Function. (United States)

    Kezic, Sanja; Jakasa, Ivone


    The skin barrier function is greatly dependent on the structure and composition of the uppermost layer of the epidermis, the stratum corneum (SC), which is made up of flattened anucleated cells surrounded by highly organized and continuous lipid matrix. The interior of the corneocytes consists mainly of keratin filaments aggregated by filaggrin (FLG) protein. Next, together with several other proteins, FLG is cross-linked into a mechanically robust cornified cell envelope providing a scaffold for the extracellular lipid matrix. In addition to its role for the SC structural and mechanical integrity, FLG degradation products account in part for the water-holding capacity and maintenance of acidic pH of the SC, both crucial for the epidermal barrier homoeostasis by regulating activity of multiple enzymes that control desquamation, lipid synthesis and inflammation. The major determinant of FLG expression in the skin are loss-of-function mutations in FLG, the strongest genetic risk factor for atopic dermatitis (AD), an inflammatory skin disease characterized by a reduced skin barrier function. The prevalence of FLG mutations varies greatly among different populations and ranges from about 10% in Northern Europeans to less than 1% in the African populations. An impaired skin barrier facilitates absorption of potentially hazardous chemicals, which might cause adverse effects in the skin, such as contact dermatitis, or systemic toxicity after their passage into blood. In another direction, a leaky epidermal barrier will lead to enhanced loss of water from the skin. A recent study has shown that even subtle increase in epidermal water loss in newborns increases the risk for AD. Although there are multiple modes of action by which FLG might affect skin barrier it is still unclear whether and how FLG deficiency leads to the reduced skin barrier function. This chapter summarizes the current knowledge in this field obtained from clinical studies, and animal and in vitro models

  12. Skin-light interaction of three main chromofores in skin affected by Port Wine Stain (United States)

    Mújica Ascencio, S.; Velázquez González, J. S.; Álvarez Chávez, J. A.


    In this paper, simulation and mathematical analysis of the absorption, dispersion and dynamics of laser light generated at 690nm and its interaction with skin affected by the Port Wine Stain is presented. The absorption coefficient and penetration depth of water, hemoglobin and oxy-hemoglobin, as key chromophores are calculated. A suitable wavelength for possible treatment on Port Wine Stain located in the skin layers such as Dermis and Hypodermis is determined. The presentation will include a full fiber laser design description, detailed skin affectation explanation and preliminary results.

  13. Skin Cancer Foundation (United States)

    ... Host a Fundraising Event | About Us | Store The Skin Cancer Foundation The Skin Cancer Foundation is the ... A "Sunscreen Gene"? Skin Cancer Facts & Statistics The Skin Cancer Foundation's Champions for Change Gala 2016 Learn ...

  14. Skin Pigmentation Disorders (United States)

    Pigmentation means coloring. Skin pigmentation disorders affect the color of your skin. Your skin gets its color from a pigment called melanin. Special cells in the skin make melanin. When these cells become damaged or ...

  15. Skin Bleaching


    Ahmed, Samira M.


    In this project, I aim to investigate the reasoning behind the practice of skin bleaching by analyzing the documentary ”Dark Girls”, to gain a better understanding of race and colorism issues. Also this project tries to see if there is a connection with history and if this has been a part of making the european beauty ideal determine the choices black’s make in regards to beauty.

  16. Meloxicam transdermal delivery: effect of eutectic point on the rate and extent of skin permeation

    Directory of Open Access Journals (Sweden)

    Soliman Mohammadi-Samani


    Conclusion: This study set out to determine that thymol plays as a skin permeation enhancer and increases the meloxicam skin absorption and this enhancement is significant at the eutectic point of drug-enhancer mixture.

  17. Cutaneous skin tag (United States)

    Skin tag; Acrochordon; Fibroepithelial polyp ... have diabetes. They are thought to occur from skin rubbing against skin. ... The tag sticks out of the skin and may have a short, narrow stalk connecting it to the surface of the skin. Some skin tags are as long as ...

  18. Influence of metabolism in skin on dosimetry after topical exposure

    Energy Technology Data Exchange (ETDEWEB)

    Bronaugh, R.L.; Collier, S.W.; Macpherson, S.E.; Kraeling, M.E.K. [Food and Drug Administration, Washington, DC (United States)


    Metabolism of chemicals occurs in skin and therefore should be taken into account when one determines topical exposure dose. Skin metabolism is difficult to measure in vivo because biological specimens may also contain metabolites from other tissues. Metabolism in skin during percutaneous absorption can be studied with viable skin in flow-through diffusion cells. Several compounds metabolized by microsomal enzymes in skin (benzo[a]pyrene and 7-ethoxycoumarin) penetrated human and hairless guinea pig skin predominantly unmetabolized. However, compounds containing a primary amino group (p-aminobenzoic acid, benzocaine, and azo color reduction products) were substrates for acetyltransferase activity in skin and were substantially metabolized during absorption. A physiologically based pharmacokinetic model has been developed with an input equation, allowing modeling after topical exposure. 14 refs., 3 figs., 4 tabs.

  19. 两种盐酸特比萘芬乳膏经离体小型猪皮渗透吸收的比较研究%The Comparative Studies on Percutaneous Absorption for Two Kind of Terbinafine Hydrochloride Cream by in vitro Tibet Minipig's Skin

    Institute of Scientific and Technical Information of China (English)

    罗荣; 周临; 陈卫


    目的 比较研究两家企业生产的盐酸特比萘芬乳膏对离体小型猪皮的透皮吸收性能.方法 采用改良的Franz扩散池,离体小型猪皮片涂药后不同时间采样,用高效液相色谱法测定接收液和皮片中盐酸特比萘芬的浓度.结果 盐酸特比萘芬乳膏透皮释放量很低,在80%乙醇生理盐水释放液中,某企业生产的乳膏产品和中美天津史克制药有限公司生产的乳膏产品在48h时累积透皮渗透量分别为55.23 mg/cm2和63.33 mg/cm2,48 h的累积透过率分别为:1.09%、1.19%.结论 两家企业生产的乳膏产品在相同渗透介质下,对于离体小型猪皮的透皮无显著性差别,二者透皮情况相当.盐酸特比萘芬乳膏主成分大部分滞留在皮肤上,只有极少数透过皮肤屏障,有利于其发挥局部治疗作用.%Objective To study the percutaneous absorption of terbinafine hydrochloride cream through in vitro Tibet minipig's skins, and compare the penetration absorption of domestic certain enterprise product with GlaxoSmithKline china product. Methods Using the modified Franz diffusion cell, samples were collected at different time after the drug was applied. The concentration of terbinafine hydrochloride in the samples was measured by HPLC. Results The penetration release quantities of terbinafine hydrochloride across Tibet minipig skins in 80% ethanol saline solution in 48h were very low, only 63.33 mg · cm2 for GlaxoSmithKline China product, and 55.23 mg · cm2 for certain enterprise product, and the percolation rate were 1.19% and 1.09%, respectively. Conclusion The percutaneous absorption of terbinafine hydrochloride cream was very low between two products without significant difference. The penetration absorbency through Tibet minipig skins of certain enterprise cream is similar to GlaxoSmithKline china product. The most of the main components of terbinafine hydrochloride cream remain in the surface of the skins, only a few through the

  20. Skin Keratins. (United States)

    Wang, Fengrong; Zieman, Abigail; Coulombe, Pierre A


    Keratins comprise the type I and type II intermediate filament-forming proteins and occur primarily in epithelial cells. They are encoded by 54 evolutionarily conserved genes (28 type I, 26 type II) and regulated in a pairwise and tissue type-, differentiation-, and context-dependent manner. Keratins serve multiple homeostatic and stress-enhanced mechanical and nonmechanical functions in epithelia, including the maintenance of cellular integrity, regulation of cell growth and migration, and protection from apoptosis. These functions are tightly regulated by posttranslational modifications as well as keratin-associated proteins. Genetically determined alterations in keratin-coding sequences underlie highly penetrant and rare disorders whose pathophysiology reflects cell fragility and/or altered tissue homeostasis. Moreover, keratin mutation or misregulation represents risk factors or genetic modifiers for several acute and chronic diseases. This chapter focuses on keratins that are expressed in skin epithelia, and details a number of basic protocols and assays that have proven useful for analyses being carried out in skin.

  1. [In vitro percutaneous absorption of silver nanoparticles]. (United States)

    Filon, F Larese; D'Agostin, F; Crosera, M; Adami, G; Rosani, R; Romano, C; Bovenzi, M; Maina, G


    There is a growing interest in the debate on nanoparticle safety for topical use. The benefits of nanoparticles have been shown in several scientific fields, but little is known about their potential to penetrate the skin lies. This study aims at evaluating in vitro silver nanoparticles skin penetration. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin. Physiological solution was used as receiving phase and 70 microg/cm2 of silver nanoparticles dispersed in synthetic sweat were applied as donor phase to the outer surface of the skin for 24h. The receptor fluid measurements were performed by Electro Thermal Atomic Absorption Spectroscopy (ETAAS). Silver concentration of 0.2 microg/L was found in the receiving solutions of two cells, in which damaged skin membranes were set up. In the other tests, we obtained a silver concentration below the limit of detection in the receiving cells. Our experimental data show that silver nanoparticles permeation through intact and damaged skin is negligible. These findings are consistent with previously published results. Further researches are necessary to explore skin absorption of silver nanoparticles.

  2. Skin color - patchy (United States)

    ... page: // Skin color - patchy To use the sharing features on this page, please enable JavaScript. Patchy skin color is areas where the skin color is irregular. ...

  3. Antioxidant cosmeto-textiles: skin assessment. (United States)

    Alonso, Cristina; Martí, Meritxell; Martínez, Vanessa; Rubio, Laia; Parra, José L; Coderch, Luisa


    Resveratrol, a natural product, has been reported to have antioxidant activities such as the scavenging of free radicals. This compound could be used in the dermocosmetic field to protect the skin from oxidative stress. In this work, the percutaneous profile of resveratrol in ethanol solutions through pig skin was determinated by an in vitro methodology. The percutaneous absorption of resveratrol was measured and compared with trolox, an analogous of Vitamin E. Both antioxidants were found in all skin sections (stratum corneum, epidermis, and dermis). Besides, the free radical scavenging activity of resveratrol and trolox has been evaluated using DPPH method. The effective dose (ED₅₀) of compounds and DPPH radical inhibition in each skin layer were evaluated. Under the conditions used for these experiments, it can be deduced that resveratrol is more efficient than trolox as an antioxidant, also in the inner skin layers. The cosmeto-textiles with an active substance incorporated into their structure are increasingly used in the cosmetics and pharmaceutical industries. The action of several cosmeto-textiles on the skin was assessed by in vitro and in vivo methodologies. Samples of these cosmeto-textiles were prepared with resveratrol incorporated into cotton and polyamide fabrics. An in vitro percutaneous absorption was used to demonstrate the delivery of the resveratrol from the textile to the different skin layers (stratum corneum, epidermis, and dermis). Additionally, these cosmeto-textiles containing the antioxidant were applied onto the forearms of volunteers to evaluate the textiles' efficacy in skin penetration. The antioxidant's antiradical capacity was evaluated using the DPPH method. Results showed that resveratrol could be detected in the dermis, epidermis, and stratum corneum (SC) by an in vitro percutaneous absorption method and was also detected in the outermost layers of the SC by an in vivo method (stripping). A smaller amount of resveratrol was

  4. Human skin penetration of silver nanoparticles through intact and damaged skin. (United States)

    Larese, Francesca Filon; D'Agostin, Flavia; Crosera, Matteo; Adami, Gianpiero; Renzi, Nadia; Bovenzi, Massimo; Maina, Giovanni


    There is a growing interest on nanoparticle safety for topical use. The benefits of nanoparticles have been shown in several scientific fields, but little is known about their potential to penetrate the skin. This study aims at evaluating in vitro skin penetration of silver nanoparticles. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin. Physiological solution was used as receiving phase and 70 microg/cm2 of silver nanoparticles coated with polyvinylpirrolidone dispersed in synthetic sweat were applied as donor phase to the outer surface of the skin for 24h. The receptor fluid measurements were performed by electro thermal atomic absorption spectroscopy (ETAAS). Human skin penetration was also determined by using transmission electron microscope (TEM) to verify the location of silver nanoparticles in exposed membranes. Median silver concentrations of 0.46 ng cm(-2) (range skin (eight cells) and on damaged skin (eight cells), respectively. Twenty-four hours silver flux permeation in damaged skin was 0.62+/-0.2 ng cm(-2) with a lag time <1h. Our experimental data showed that silver nanoparticles absorption through intact and damaged skin was very low but detectable, and that in case of damaged skin it was possible an increasing permeation of silver applied as nanoparticles. Moreover, silver nanoparticles could be detected in the stratum corneum and the outermost surface of the epidermis by electron microscopy. We demonstrated for the first time that silver applied as nanoparticles coated with polyvinylpirrolidone is able to permeate the damaged skin in an in vitro diffusion cell system.

  5. Human Skin Penetration of Cobalt Nanoparticles Through Intact and Damaged Skin


    LARESE FILON Francesca; Crosera, Matteo; TIMEUS Elena; Adami, Gianpiero; Bovenzi, Massimo; Ponti, Jessica; Maina, Giovanni


    Cobalt nanoparticles (CoNPs) are produced for many applications but there is a lack of data on human absorption. The aim of our study was to evaluate the CoNPs skin absorption. Experiments were performed using Franz cells with human skin. Physiological solution was used as receiving phase and 1.0 mg cm-2 of CoNPs was applied as donor phase for 24 h. Mean Co content of 8.3 ± 1.5 ng cm-2 and 1.87 ± 0.86 ug cm-2 were found in the receiving solutions of cells where the CoNPs suspension was app...

  6. Terahertz spectroscopy of human skin constituents in suspension (United States)

    Joseph, Cecil; Yaroslavsky, Anna; Al-Arashi, Munir; Gatesman, Andrew; Goyette, Thomas; Giles, Robert


    Continuous wave terahertz imaging has the potential to offer a non-invasive medical imaging modality for detecting different types of human cancers. The aim of this study was to identify frequencies of interest for continuous wave terahertz imaging of skin cancer. The absorption characteristics of water, collagen, and elastin were studied in the range between 20 and 100cm-1. In addition, we have recorded and analyzed the teraherz absorption spectra of several substances that are present in human skin (i.e. tryptophan, tyrosine, melanin, urocanic acid, keratin) and their water suspensions with the goal of using them as biomarkers for skin cancer detection.

  7. Skin Care and Aging (United States)

    ... version of this page please turn Javascript on. Skin Care and Aging How Aging Affects Skin Your skin changes with age. It becomes thinner, ... to make it feel and look better. Dry Skin and Itching Click for more information Many older ...

  8. An improved model for studies on transdermal drug absorption invivo in rats

    NARCIS (Netherlands)

    VOLLMER, U; MULLER, BW; WILFFERT, B; Peters, Thies


    In rats, transdermal drug absorption can be studied under physiological conditions by cannulating the peripheral skin vein, draining the area of the skin which is used for drug application, and collecting the blood. This method leads to decreased blood volume, which causes a reduction in skin blood

  9. An improved model for studies on transdermal drug absorption in-vivo in rats

    NARCIS (Netherlands)

    Vollmer, U.; Muller, B.W.; Wilffert, B.; Peters, Thies


    In rats, transdermal drug absorption can be studied under physiological conditions cannulating the peripheral skin vein, draining the area of the skin which is used for drug application, and collecting the blood. This method leads to decreased blood volume, which causes a reduction in skin blood flo

  10. What Is Melanoma Skin Cancer? (United States)

    ... Skin Cancer About Melanoma Skin Cancer What Is Melanoma Skin Cancer? Cancer starts when cells in the ... pigment, causing the skin to tan or darken. Melanoma skin cancers Melanoma is a cancer that begins ...

  11. Human skin penetration of cobalt nanoparticles through intact and damaged skin. (United States)

    Larese Filon, Francesca; Crosera, Matteo; Timeus, Elisa; Adami, Gianpiero; Bovenzi, Massimo; Ponti, Jessica; Maina, Giovanni


    Cobalt nanoparticles (CoNPs) are produced for several industrial and biomedical applications but there is a lack of data on human cutaneous absorption. Cobalt is also a skin sensitizer that can cause allergic contact dermatitis. Co applied as NPs, due to their small size and high surface, can penetrate into the skin in higher amount that bulk material. The aim of this study was to evaluate the absorption of Co applied as NPs in both intact and damaged skin. Experiments were performed using Franz cells and 1.0 mg cm(-2) of CoNPs was applied as donor phase for 24h. Mean Co content of 8.5 ± 1.2 ng cm(-2) and 1.87 ± 0.86 μg cm(-2) were found in the receiving solutions of Franz cells when the CoNPs suspension was applied on intact skin and on damaged skin, respectively. Twenty-four hours Co flux permeation was 76 ± 49 ng cm(-2)h(-1) in damaged skin with a lag time of 2.8 ± 2.1h. This study suggests that Co applied as NPs is able to penetrate the human skin in an in vitro diffusion cell system.

  12. [Sarcoidosis of the skin]. (United States)

    Suga, Y; Ogawa, H


    Sarcoidosis is characterized by formation of epithelioid-cell tubercules, without caseation, of the affected organ systems. The mediastinum, peripheral lymph nodes and eyes, in addition to the skin, are most frequently affected. Between 10% and 30% of patients with systemic sarcoidosis in Japan have skin lesions. Skin sarcoidosis is morphologically classified into three basic groups, erythema nodosum, scar sarcoidosis and skin sarcoid. Skin sarcoid is characterized by specific cutaneous lesions of sarcoidosis, and may take nodular, plaque, angiolupoid, subcutaneous and some other forms. Clinical manifestations of the cutaneous lesions are usually asymptomatic and polymorphous. Skin biopsy is, however, often highly useful for confirming a diagnosis of sarcoidosis.

  13. Human skin penetration of gold nanoparticles through intact and damaged skin. (United States)

    Filon, Francesca Larese; Crosera, Matteo; Adami, Gianpiero; Bovenzi, Massimo; Rossi, Federica; Maina, Giovanni


    Gold nanoparticles (AuNPs) are produced for many applications but there is a lack of available data on their skin absorption. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin. A physiological solution was used as receiving phase and 0.5 mL (1st exp) and 1.5 mL (2nd exp) of a solution containing 100 mg L⁻¹ of AuNPs (15 and 45 μg cm⁻², respectively) was applied as donor phase to the outer surface of the skin for 24 h. Skin absorption was dose dependent. Mean gold content of 214.0 ± 43.7 ng cm⁻² and 187.7 ± 50.2 ng cm⁻² were found in the receiving solutions of cells where the AuNPs solution was applied in higher concentration on intact skin (8 Franz cells) and on damaged skin (8 Franz cells), respectively. Twenty-four hours gold flux permeation was 7.8 ± 2.0 ng cm⁻² h⁻¹ and 7.1 ± 2.5 ng cm⁻² h⁻¹ in intact and damaged skin, respectively, with a lag time less than 1 hour. Transmission Electron Microscope analysis on skin samples and chemical analysis using Inductively Coupled Plasma-Mass Spectrometry demonstrated the presence of AuNPs into epidermis and dermis. This study showed that AuNPs are able to penetrate the human skin in an in vitro diffusion cell system.

  14. Relative absorption and dermal loading of chemical substances: Consequences for risk assessment

    NARCIS (Netherlands)

    Buist, H.E.; Schaafsma, G.; Sandt, J.J.M. van de


    Quantification of skin absorption is an essential step in reducing the uncertainty of dermal risk assessment. Data from literature indicate that the relative dermal absorption of substances is dependent on dermal loading. Therefore, an internal exposure calculated with absorption data determined at

  15. Skin Stem Cells in Skin Cell Therapy

    Directory of Open Access Journals (Sweden)

    Mollapour Sisakht


    Full Text Available Context Preclinical and clinical research has shown that stem cell therapy is a promising therapeutic option for many diseases. This article describes skin stem cells sources and their therapeutic applications. Evidence Acquisition Compared with conventional methods, cell therapy reduces the surgical burden for patients because it is simple and less time-consuming. Skin cell therapy has been developed for variety of diseases. By isolation of the skin stem cell from the niche, in vitro expansion and transplantation of cells offers a surprising healing capacity profile. Results Stem cells located in skin cells have shown interesting properties such as plasticity, transdifferentiation, and specificity. Mesenchymal cells of the dermis, hypodermis, and other sources are currently being investigated to promote regeneration. Conclusions Because skin stem cells are highly accessible from autologous sources and their immunological profile is unique, they are ideal for therapeutic approaches. Optimization of administrative routes requires more investigation own to the lack of a standard protocol.

  16. Metabolism of skin-absorbed resveratrol into its glucuronized form in mouse skin.

    Directory of Open Access Journals (Sweden)

    Itsuo Murakami

    Full Text Available Resveratrol (RESV is a plant polyphenol, which is thought to have beneficial metabolic effects in laboratory animals as well as in humans. Following oral administration, RESV is immediately catabolized, resulting in low bioavailability. This study compared RESV metabolites and their tissue distribution after oral uptake and skin absorption. Metabolomic analysis of various mouse tissues revealed that RESV can be absorbed and metabolized through skin. We detected sulfated and glucuronidated RESV metabolites, as well as dihydroresveratrol. These metabolites are thought to have lower pharmacological activity than RESV. Similar quantities of most RESV metabolites were observed 4 h after oral or skin administration, except that glucuronidated RESV metabolites were more abundant in skin after topical RESV application than after oral administration. This result is consistent with our finding of glucuronidated RESV metabolites in cultured skin cells. RESV applied to mouse ears significantly suppressed inflammation in the TPA inflammation model. The skin absorption route could be a complementary, potent way to achieve therapeutic effects with RESV.

  17. Examine Your Skin

    Medline Plus

    Full Text Available ... Store In Memory Melanoma Info Melanoma Facts Melanoma Prevention Sunscreen Suggestions Examine Your Skin Newly Diagnosed? Understanding ... video. UPDATED: November 23, 2016 Melanoma Facts Melanoma Prevention Sunscreen Suggestions Examine Your Skin Newly Diagnosed? Understanding ...

  18. Examine Your Skin

    Medline Plus

    Full Text Available ... Support Donate Share Facebook Twitter Newsletter Examine Your Skin Watch the video below and in only two minutes, you can learn to examine your skin. A special thanks to Dr. Martin Weinstock, MD, ...

  19. Neuromodulators for Aging Skin (United States)

    ... Dermatologic Surgery Expertise for the life of your skin (TM) Public Resources Dermatologic Surgery Conditions Treatments and ... learn-more"> 3 million Americans are diagnosed with skin cancer every year Any suspicious new growths or ...

  20. Skin Cancer Trends (United States)

    ... Trends Behavior Rates What CDC Is Doing Skin Cancer Prevention Progress Report The Burning Truth Initiative A Base Tan Is Not a Safe Tan Tanned Skin Is Not Healthy Skin Controlled Tanning Is Not Safe Tanning Guidelines for School ... Melanoma Surveillance in the U.S. Related Links ...

  1. On skin expansion. (United States)

    Pamplona, Djenane C; Velloso, Raquel Q; Radwanski, Henrique N


    This article discusses skin expansion without considering cellular growth of the skin. An in vivo analysis was carried out that involved expansion at three different sites on one patient, allowing for the observation of the relaxation process. Those measurements were used to characterize the human skin of the thorax during the surgical process of skin expansion. A comparison between the in vivo results and the numerical finite elements model of the expansion was used to identify the material elastic parameters of the skin of the thorax of that patient. Delfino's constitutive equation was chosen to model the in vivo results. The skin is considered to be an isotropic, homogeneous, hyperelastic, and incompressible membrane. When the skin is extended, such as with expanders, the collagen fibers are also extended and cause stiffening in the skin, which results in increasing resistance to expansion or further stretching. We observed this phenomenon as an increase in the parameters as subsequent expansions continued. The number and shape of the skin expanders used in expansions were also studied, both mathematically and experimentally. The choice of the site where the expansion should be performed is discussed to enlighten problems that can lead to frustrated skin expansions. These results are very encouraging and provide insight into our understanding of the behavior of stretched skin by expansion. To our knowledge, this study has provided results that considerably improve our understanding of the behavior of human skin under expansion.

  2. Skin self-exam (United States)

    Skin cancer - self-exam; Melanoma - self-exam; Basal cell cancer - self-exam; Squamous cell - self-exam; Skin mole - self-exam ... Experts do not agree on whether or not skin self-exams should be performed. So there is ...

  3. Microbiome and skin diseases

    NARCIS (Netherlands)

    Zeeuwen, P.L.J.M.; Kleerebezem, M.; Timmerman, H.M.; Schalkwijk, J.


    PURPOSE OF REVIEW: This article reviews recent findings on the skin microbiome. It provides an update on the current understanding of the role of microbiota in healthy skin and in inflammatory and allergic skin diseases. RECENT FINDINGS: Advances in computing and high-throughput sequencing technolog

  4. Microbiome and skin diseases

    NARCIS (Netherlands)

    Zeeuwen, P.L.; Kleerebezem, M.; Timmerman, H.M.; Schalkwijk, J.


    Purpose of review: This article reviews recent findings on the skin microbiome. It provides an update on the current understanding of the role of microbiota in healthy skin and in inflammatory and allergic skin diseases. Recent findings: Advances in computing and high-throughput sequencing technolog

  5. Ultrasound skin imaging. (United States)

    Alfageme Roldán, F


    The interaction of high-frequency ultrasound waves with the skin provides the basis for noninvasive, fast, and accessible diagnostic imaging. This tool is increasingly used in skin cancer and inflammatory conditions as well as in cosmetic dermatology. This article reviews the basic principles of skin ultrasound and its applications in the different areas of dermatology.

  6. Psychoneuroimmunology and the Skin. (United States)

    Honeyman, Juan F


    The nervous, immune, endocrine and integumentary systems are closely related and interact in a number of normal and pathological conditions. Nervous system mediators may bring about direct changes to the skin or may induce the release of immunological or hormonal mediators that cause pathological changes to the skin. This article reviews the psychological mechanisms involved in the development of skin diseases.

  7. Permeation of chromium salts through human skin in vitro

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Fullerton, A; Avnstorp, C


    Chromium permeation studies were performed on full thickness human skin in diffusion cells. All samples were analysed for the total chromium content by graphite furnace Zeeman-corrected atomic absorption spectrometry. Some samples were analysed by an ion chromatographic method permitting...... the simultaneous determination of Cr(VI) and Cr(III) as well. The amounts of chromium found in all skin layers were significantly higher when potassium dichromate was applied to the skin compared with chromium chloride or chromium nitrate. Chromium could only be detected in the recipient phase after application...... of the dichromate solution. Chromium skin levels increased with increasing concentrations of applied chromium salts up to 0.034 M Cr. The amount of chromium in recipient phase and skin layers increased with increasing pH when the applied solution contained potassium dichromate. This was ascribed to a decreased skin...

  8. Pursuing prosthetic electronic skin (United States)

    Chortos, Alex; Liu, Jia; Bao, Zhenan


    Skin plays an important role in mediating our interactions with the world. Recreating the properties of skin using electronic devices could have profound implications for prosthetics and medicine. The pursuit of artificial skin has inspired innovations in materials to imitate skin's unique characteristics, including mechanical durability and stretchability, biodegradability, and the ability to measure a diversity of complex sensations over large areas. New materials and fabrication strategies are being developed to make mechanically compliant and multifunctional skin-like electronics, and improve brain/machine interfaces that enable transmission of the skin's signals into the body. This Review will cover materials and devices designed for mimicking the skin's ability to sense and generate biomimetic signals.

  9. Photoreactivation in bacteria and in skin

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, B M


    In many procaryotic and eucaryotic cells, photoreactivating enzyme mediates light-dependent repair of uv-induced damage; the enzyme binds to a pyrimidine dimer in DNA, and, on absorption of a photon (300 to 600 nm), specifically monomerizes the dimer, thus repairing the DNA. Photoreactivating enzyme has been found in human tissues and human cells in culture can photoreactivate cellular dimers, and can mediate photoreactivation of Herpes (human fibroblasts) and Epstein-Barr virus (human leukocytes). Measurements of pyrimidine dimer formation and repair in human skin indicate that detectable numbers of dimers are formed at 1 minimal erythemal dose, that the dimiers are rapidly removed in skin kept in the absence of light, and they are more rapidly removed when the skin is exposed to visible light. Whether this apparent photorecovery is true, enzymatic photoreactivation is yet to be determined.

  10. [Assessment of ultraviolet radiation penetration into human skin. I. Theoretical analysis]. (United States)

    Cader, A; Jankowski, J


    This is one of the two articles under the same title "Assessment of ultraviolet radiation penetrating into human skin" which are aimed at presenting a part of broader studies in this area. They drive at identifying biophysical aspects of the effects of ultraviolet radiation on human skin. In order to characterise such parameters as UV reflectance from the skin surface of UV absorption and dispersion coefficients, it is necessary to develop appropriate methods. In Part I--"Theoretical analysis", theoretical principles for interpreting measurements of radiation dispersed in different geometrical configurations are presented. They can serve as a basis for estimating the values of UV linear absorption and dispersion coefficients in skin tissues.

  11. D-xylose absorption (United States)

    ... this page: // D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  12. Physicochemical and functional properties of gelatin extracted from Yak skin. (United States)

    Xu, Mengqi; Wei, Lixin; Xiao, Yuancan; Bi, Hongtao; Yang, Hongxia; Du, Yuzhi


    Different molecular weight distribution (MWD) gelatin was extracted from Yak skin after enzymatic pretreatments and their physicochemical and functional properties (SDS-PAGE, UV-vis absorption spectra, DSC, FT-IR, Amino acid analysis, AFM, emulsibility and foamability) were analyzed. The gelatin was extracted by pepsin and got different MWD of Yak skin gelatin by controlling the enzymolysis time. The SDS-PAGE showed the MWD of the Yak skin gelatin. The UV-vis absorption turned out that the broad MWD of Yak skin gelatin had a higher maximum absorption peaks. The FT-IR and AFM indicated that the gelatin structures and microstructures changed with the change of the MWD. The broad MWD of the Yak skin gelatin had a higher denaturation temperature (TD), and it was higher than most of the other mammals and marine biological gelatin. The broad MWD gelatin also had higher imino acids (proline and hydroxyproline) contents and lower foamability and emulsibility compared to the narrow MWD gelatin. These findings, obtained for the first time for Yak skin gelatin, showed that it has great potential for application as an alternative to commercial gelatin due to its good thermotolerance, particularly in the applications of the biological materials, stabilizer of thermo-tolerant and so on.

  13. Skin barrier function

    DEFF Research Database (Denmark)


    Renowned experts present the latest knowledge Although a very fragile structure, the skin barrier is probably one of the most important organs of the body. Inward/out it is responsible for body integrity and outward/in for keeping microbes, chemicals, and allergens from penetrating the skin. Since...... the role of barrier integrity in atopic dermatitis and the relationship to filaggrin mutations was discovered a decade ago, research focus has been on the skin barrier, and numerous new publications have become available. This book is an interdisciplinary update offering a wide range of information...... on the subject. It covers new basic research on skin markers, including results on filaggrin and on methods for the assessment of the barrier function. Biological variation and aspects of skin barrier function restoration are discussed as well. Further sections are dedicated to clinical implications of skin...

  14. Basophils and skin disorders. (United States)

    Borriello, Francesco; Granata, Francescopaolo; Marone, Gianni


    Since their discovery in 1879, basophils have been viewed as circulating blood granulocytes with limited immune function. New research tools for their functional analysis in vivo have revealed previously unrecognized roles for basophils in several skin disorders. Human basophils infiltrate different skin lesions and have been implicated in the pathogenesis of diseases ranging from chronic idiopathic urticaria to systemic lupus erythematosus. In mouse models, basophils participate in IgE-mediated chronic allergic inflammation of the skin and have a protective role in tick infestation. In this review, we discuss critical advances in our understanding of basophil biology and their roles in the pathophysiology of skin disorders.

  15. Skin Images Segmentation

    Directory of Open Access Journals (Sweden)

    Ali E. Zaart


    Full Text Available Problem statement: Image segmentation is a fundamental step in many applications of image processing. Skin cancer has been the most common of all new cancers detected each year. At early stage detection of skin cancer, simple and economic treatment can cure it mostly. An accurate segmentation of skin images can help the diagnosis to define well the region of the cancer. The principal approach of segmentation is based on thresholding (classification that is lied to the problem of the thresholds estimation. Approach: The objective of this study is to develop a method to segment the skin images based on a mixture of Beta distributions. We assume that the data in skin images can be modeled by a mixture of Beta distributions. We used an unsupervised learning technique with Beta distribution to estimate the statistical parameters of the data in skin image and then estimate the thresholds for segmentation. Results: The proposed method of skin images segmentation was implemented and tested on different skin images. We obtained very good results in comparing with the same techniques with Gamma distribution. Conclusion: The experiment showed that the proposed method obtained very good results but it requires more testing on different types of skin images.

  16. 光动力疗法治疗鲜红斑痣的基础研究 ——血啉甲醚与血卟啉衍生物吸收特性的比较%Absorptive Characteristics of HMME and HpD in Chicken Comb Skin and Vascular Endothelial Cells

    Institute of Scientific and Technical Information of China (English)

    刘凡光; 顾瑛; 富秋涛; 潘玉明; 李峻亨


    Objective Port wine stain (PWS) is a congenital vascular malformatio n of capillaries in the superficial layers of the skin. A new photosensitiz er, Hematoporphyrin monomethyl ether(HMME), has been used for photodynamic thera py of PWS. But the absorptive characteristics of HMME in vascular endothelial ce ll (EC) are still unknown. The purpose of this study is to provide a basis for p hotodynamic therapy using HMME. Methods 12 Leghorn chickens were divided into 2 groups and HMME or H pD were injected intravenously at a dose of 10 mg/kg. The blood and comb skin s ample were taken at 10 min intervals after injection. Human vascular endothelia l cells (EC) were cultured and HMME or HpD were added into culture medium in different concentration. Then, EC were incubated for different time. The content s of HMME or HpD in blood, comb skin and EC samples were measured by using spect rofluorophotometer. Results The blood clearance of HMME and HpD were rapid and similar. But the content of HMME in comb skin was significantly higher than that of HpD ( P<0.01), especially in 10, 20, 30 min after injection. HMME and HpD can be absorbed rapidly by EC and 89% of the uptake peak value were reached at 30 min after incubation. The uptake quantities of HMME and HpD w ere positively related with their incubating concentrations and the mean value o f HMME absorbed by EC was 155% higher than that of HpD (P <0.01). Conclusions HMME can be absorbed by EC of vascular network more rapidly and easely than HpD. This is advantageous to photodynamic therapy of PWS .%目的 观察新型光敏剂——血啉甲醚(HMME)在鸡冠皮肤组织和血管内皮细胞(EC )的吸收特点。 方法 莱亨鸡12只,分为HMME组和血卟啉衍生物(HpD)组,每组6只。分别静脉 注射HMME或HpD 10 mg/kg,每隔10 min取血2.5 ml 和鸡冠皮肤组织2.5 g。培养新生儿脐带EC,培养液中加入HMME或HpD,孵育浓度分 别为20、40、60、80和100 μg

  17. An overview of skin penetration enhancers: penetration enhancing activity, skin irritation potential and mechanism of action

    Directory of Open Access Journals (Sweden)

    Sarunyoo Songkro


    Full Text Available Transdermal drug delivery has attracted considerable attention over the past 2-3 decades in regard of its many potentialadvantages. However, the role of the skin as a protective barrier renders skin absorption of most drugs problematic. Therefore,skin penetration enhancers are frequently used in the field of transdermal drug delivery in order to reversibly reduce thebarrier function of the stratum corneum, the outermost layer of the skin. To date, a wide range of chemical compounds havebeen shown to enhance the skin penetration of therapeutic drugs. This review presents a critical account of the most commonlyused chemical penetration enhancers (fatty acids and surfactants, and some newer classes of chemical enhancers (terpenes,polymers, monoolein, oxazolidinones, with emphasis on their efficacy, mechanism of action, and skin irritation potential. Thisreview also discusses the traditional and more recently developed methods for the screening and evaluation of chemical penetration enhancers, and addresses the continuing problems in the rational selection of a chemical penetration enhancer for a specific drug to be delivered via the transdermal route.

  18. Skin tribology: Science friction?

    NARCIS (Netherlands)

    Heide, van der E.; Zeng, X.; Masen, M.A.


    The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems. In fact, effective solutions to friction and wear related questions can be found in our everyday life. An important part is related to skin tribology, as the human skin is fre

  19. Deformable skinning on bones

    DEFF Research Database (Denmark)

    Larsen, Bent Dalgaard; Petersen, Kim Steen; Jakobsen, Bjarke


    Applying skin to a model is a relatively simple task to implement. Nonetheless it seems that no good resource exists that describes both the concepts and math necessary to understand and implement skinning. The intention of this article is an attempt to give a thoroughly description of the theore...

  20. Skin Diseases: Skin and Sun—Not a good mix (United States)

    Skip Navigation Bar Home Current Issue Past Issues Skin Diseases Skin and Sun —Not a good mix Past Issues / ... of this page please turn Javascript on. Good skin care begins with sun safety. Whether it is ...

  1. Cobalt Oxide Nanoparticles: Behavior towards Intact and Impaired Human Skin and Keratinocytes Toxicity


    Marcella Mauro; Matteo Crosera; Marco Pelin; Chiara Florio; Francesca Bellomo; Gianpiero Adami; Piero Apostoli; Giuseppe Palma; Massimo Bovenzi; Marco Campanini; Francesca Larese Filon


    Skin absorption and toxicity on keratinocytes of cobalt oxide nanoparticles (Co3O4NPs) have been investigated. Co3O4NPs are commonly used in industrial products and biomedicine. There is evidence that these nanoparticles can cause membrane damage and genotoxicity in vitro, but no data are available on their skin absorption and cytotoxicity on keratinocytes. Two independent 24 h in vitro experiments were performed using Franz diffusion cells, using intact (experiment 1) and needle-abraded huma...

  2. Bionanomaterials for skin regeneration

    CERN Document Server

    Leonida, Mihaela D


    This book gives a concise overview of bionanomaterials with applications for skin regeneration. The advantages and challenges of nanoscale materials are covered in detail, giving a basic view of the skin structure and conditions that require transdermal or topical applications. Medical applications, such as wound healing, care for burns, skin disease, and cosmetic care, such as aging of the skin and photodamage, and how they benefit from bionanomaterials, are described in detail. A final chapter is devoted to the ethical and social issues related to the use of bionanomaterials for skin regeneration. This is an ideal book for researchers in materials science, medical scientists specialized in dermatology, and cosmetic chemists working in formulations. It can also serve as a reference for nanotechnologists, dermatologists, microbiologists, engineers, and polymer chemists, as well as students studying in these fields.

  3. Infrared spectroscopic measurement of skin hydration and sebum levels and comparison to corneometer and sebumeter (United States)

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


    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.

  4. Percutaneous absorption of methimazole: an in vitro study of the absorption pharmacokinetics for two different vehicles. (United States)

    Hill, K E; Mills, P C; Jones, B R; Bolwell, C F; Aberdein, D; Chambers, J P


    The use of transdermal medications in cats has become popular in veterinary medicine due to the ease of administration compared to oral medication. However, the research to support systemic absorption of drugs applied to the pinna after transdermal administration in cats is limited. The aim of this study was to characterize the percutaneous absorption pharmacokinetics of methimazole in a lipophilic vehicle compared to methimazole in Pluronic(®) lecithin organogel (PLO) using a finite dose applied to feline ear skin in an in vitro Franz cell model. The two formulations of methimazole (10 mg) were applied to the inner stratum corneum of six pairs of feline ears. The receptor medium was sampled up to 30 h post-administration, and methimazole concentrations were measured using high-performance liquid chromatography (HPLC). Histological examination of all ears was undertaken as small differences in the thickness of ear skin may have contributed to inter-individual differences in methimazole absorption between six cats. Methimazole was absorbed more completely across the pinnal skin when administered in the lipophilic vehicle compared to administration in the PLO gel (P < 0.001).

  5. Comparative in vitro-in vivo percutaneous absorption of the pesticide propoxur

    NARCIS (Netherlands)

    Sandt, J.J.M. van de; Meuling, W.J.A.; Elliott, G.R.; Cnubben, N.H.P.; Hakkert, B.C.


    In vitro and in vivo skin absorption of the pesticide propoxur (2-isopropoxyphenyl N-methyl carbamate, commercially Baygon(TM) and Unden(TM); log Po/w 1.56, MW 209.2) was investigated. In vivo studies were performed in rats and human volunteers, applying the test compound to the dorsal skin and the

  6. Tips for Relieving Dry Skin (United States)

    ... skin is dry, stop using: Deodorant soaps Skin care products that contain alcohol, fragrance, retinoids, or alpha-hydroxy acid (AHA) Avoiding these products will help your skin retain its natural oils. 6. Wear gloves. Our hands are often ...

  7. 6 Common Cancers - Skin Cancer (United States)

    ... Bar Home Current Issue Past Issues 6 Common Cancers - Skin Cancer Past Issues / Spring 2007 Table of Contents For ... AP Photo/Herald-Mail, Kevin G. Gilbert Skin Cancer Skin cancer is the most common form of ...

  8. Interactions of skin thickness and physicochemical properties of test compounds in percutaneous penetration studies

    NARCIS (Netherlands)

    Wilkinson, S.C.; Maas, W.J.M.; Nielsen, J.B.; Greaves, L.C.; Sandt, J.J.M. van de; Williams, F.M.


    Objectives: To determine the effect of skin thickness on the percutaneous penetration and distribution of test compounds with varying physicochemical properties using in vitro systems. Studies were carried out in accordance with OECD guidelines on skin absorption tests. Methods: Percutaneous penetra

  9. Skin Picking Disorder

    Directory of Open Access Journals (Sweden)

    Pinar Cetinay Aydin


    Full Text Available Skin picking disorder is not a dermatological disorder and it is a table characterized with picking skin excessively and repetitively, leading to damage in skin tissue. Unlike normal picking behaviour, psychogenic skin picking is repetitive and it can lead to severe damage in the skin and even complications which constitute vital danger. While some patients define frequent but short lasting picking attacks, others define rarer attacks which last a few hours. Skin picking disorder, which is not included in the classification systems up to DSM-5 as a separate diagnosis category, is included as an independent diagnosis in Obsessive Compulsive Disorder and Associated Disorders category in DSM-5. In case reports, open label studies and double blind studies selective serotonin reuptake inhibitors are shown to be effective in the treatment of skin picking disorder. Mostly, cognitive-behaviourial techniques are used and have been proven to be useful in psychotherapy. Habit reversal is one of the behaviourial techniques which are frequently applied, give positive results in which well-being state can be maintained. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(4.000: 401-428

  10. Archaea on human skin.

    Directory of Open Access Journals (Sweden)

    Alexander J Probst

    Full Text Available The recent era of exploring the human microbiome has provided valuable information on microbial inhabitants, beneficials and pathogens. Screening efforts based on DNA sequencing identified thousands of bacterial lineages associated with human skin but provided only incomplete and crude information on Archaea. Here, we report for the first time the quantification and visualization of Archaea from human skin. Based on 16 S rRNA gene copies Archaea comprised up to 4.2% of the prokaryotic skin microbiome. Most of the gene signatures analyzed belonged to the Thaumarchaeota, a group of Archaea we also found in hospitals and clean room facilities. The metabolic potential for ammonia oxidation of the skin-associated Archaea was supported by the successful detection of thaumarchaeal amoA genes in human skin samples. However, the activity and possible interaction with human epithelial cells of these associated Archaea remains an open question. Nevertheless, in this study we provide evidence that Archaea are part of the human skin microbiome and discuss their potential for ammonia turnover on human skin.

  11. Skin and antioxidants. (United States)

    Poljsak, Borut; Dahmane, Raja; Godic, Aleksandar


    It is estimated that total sun exposure occurs non-intentionally in three quarters of our lifetimes. Our skin is exposed to majority of UV radiation during outdoor activities, e.g. walking, practicing sports, running, hiking, etc. and not when we are intentionally exposed to the sun on the beach. We rarely use sunscreens during those activities, or at least not as much and as regular as we should and are commonly prone to acute and chronic sun damage of the skin. The only protection of our skin is endogenous (synthesis of melanin and enzymatic antioxidants) and exogenous (antioxidants, which we consume from the food, like vitamins A, C, E, etc.). UV-induced photoaging of the skin becomes clinically evident with age, when endogenous antioxidative mechanisms and repair processes are not effective any more and actinic damage to the skin prevails. At this point it would be reasonable to ingest additional antioxidants and/or to apply them on the skin in topical preparations. We review endogenous and exogenous skin protection with antioxidants.

  12. Skin delivery by block copolymer nanoparticles (block copolymer micelles). (United States)

    Laredj-Bourezg, Faiza; Bolzinger, Marie-Alexandrine; Pelletier, Jocelyne; Valour, Jean-Pierre; Rovère, Marie-Rose; Smatti, Batoule; Chevalier, Yves


    Block copolymer nanoparticles often referred to as "block copolymer micelles" have been assessed as carriers for skin delivery of hydrophobic drugs. Such carriers are based on organic biocompatible and biodegradable materials loaded with hydrophobic drugs: poly(lactide)-block-poly(ethylene glycol) copolymer (PLA-b-PEG) nanoparticles that have a solid hydrophobic core made of glassy poly(d,l-lactide), and poly(caprolactone)-block-poly(ethylene glycol) copolymer (PCL-b-PEG) nanoparticles having a liquid core of polycaprolactone. In vitro skin absorption of all-trans retinol showed a large accumulation of retinol in stratum corneum from both block copolymer nanoparticles, higher by a factor 20 than Polysorbate 80 surfactant micelles and by a factor 80 than oil solution. Additionally, skin absorption from PLA-b-PEG nanoparticles was higher by one order of magnitude than PCL-b-PEG, although their sizes (65nm) and external surface (water-swollen PEG layer) were identical as revealed by detailed structural characterizations. Fluorescence microscopy of histological skin sections provided a non-destructive picture of the storage of Nile Red inside stratum corneum, epidermis and dermis. Though particle cores had a different physical states (solid or liquid as measured by (1)H NMR), the ability of nanoparticles for solubilization of the drug assessed from their Hildebrand solubility parameters appeared the parameter of best relevance regarding skin absorption.

  13. Leishmania Skin Test (United States)


    2009, a dose of 50µg will be used in the design of a phase III clinical trial. 15. SUBJECT TERMS LtSTA = Leishmania tropica Skin Test Antigen 16...2010 on a Leishmania Skin Test (LtSTA) developed from the promastigotes of Leishmania tropica . During this period a phase IIB study was in progress...diluent. The final product is referred to as Leishmania tropica Skin Test Antigen (LtSTA). Figure 3 is a schematic diagram of the Drug Product

  14. Ultrasound skin tightening. (United States)

    Minkis, Kira; Alam, Murad


    Ultrasound skin tightening is a noninvasive, nonablative method that allows for energy deposition into the deep dermal and subcutaneous tissue while avoiding epidermal heating. Ultrasound coagulation is confined to arrays of 1-mm(3) zones that include the superficial musculoaponeurotic system and connective tissue. This technology gained approval from the Food and Drug Administration as the first energy-based skin "lifting" device, specifically for lifting lax tissue on the neck, submentum, and eyebrows. Ultrasound has the unique advantage of direct visualization of treated structures during treatment. Ultrasound is a safe and efficacious treatment for mild skin tightening and lifting.

  15. Eicosanoids in skin inflammation. (United States)

    Nicolaou, Anna


    Eicosanoids play an integral part in homeostatic mechanisms related to skin health and structural integrity. They also mediate inflammatory events developed in response to environmental factors, such as exposure to ultraviolet radiation, and inflammatory and allergic disorders, including psoriasis and atopic dermatitis. This review article discusses biochemical aspects related to cutaneous eicosanoid metabolism, the contribution of these potent autacoids to skin inflammation and related conditions, and considers the importance of nutritional supplementation with bioactives such as omega-3 and omega-6 polyunsaturated fatty acids and plant-derived antioxidants as means of addressing skin health issues.

  16. Skin strain and its influence on systemic exposure to a glycol ether in offset printing workers. (United States)

    Korinth, G; Göen, T; Lakemeyer, M; Broding, H C; Drexler, H


    Under workplace conditions, it is difficult to prove the influence of skin lesions on skin penetration by chemical substances. The aim of the present study was to show whether systemic exposure to glycol ether increases due to lesions of the skin in printing workers. 28 male printers, exposed to 2-(2-butoxyethoxy)ethanol (BEE), were interviewed about the workplace exposure by a standardized questionnaire. The systemic exposure in printers was determined by biological monitoring of the main metabolite of BEE butoxyethoxyacetic acid (BEAA) in urine. Furthermore, clinical examination of the skin, transepidermal water loss, capacitance and skin surface pH measurements were carried out. Erythema and scaliness were the most important factors showing an effect on dermal absorption. The mean urinary BEAA excretions for printers with skin lesions on the hands were higher (20.62 mg/l for scaliness and 14.40 mg/l for erythema) compared to that for printers without detectable skin lesions (12.08 mg/l for scaliness and 13.03 mg/l for erythema). Bioengineering measurements to predict skin strain and percutaneous absorption were only supportive. We were able to show that by using a multiple spectrum of methods an enhancement of percutaneous absorption of BEE could be demonstrated in workers with skin lesions.

  17. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy (United States)

    Zonios, George; Dimou, Aikaterini; Galaris, Dimitrios


    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H2O2 solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  18. Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zonios, George [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Dimou, Aikaterini [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Galaris, Dimitrios [Laboratory of Biological Chemistry, School of Medicine, University of Ioannina, 45110 Ioannina (Greece)


    Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H{sub 2}O{sub 2} solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.

  19. Nutrition and magnesium absorption.

    NARCIS (Netherlands)

    Brink, E.J.


    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true magnesium abs

  20. Bioacoustic Absorption Spectroscopy (United States)


    frequencies (Ching and Weston, 1971). RESULTS Measured resonance frequencies of absorption lines, which were attributed to adult (~ 1.3 khz) and juvenile ...of adult and juvenile sardines. These results suggest that bioacoustic absorption spectroscopy measurements permit isolation of juvenile from adult...from broadband tomographic transmission loss measurements over large areas . 2. Depths of sardines and contours of phytoplankton concentrations vs. time

  1. The HI absorption "Zoo"

    NARCIS (Netherlands)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.


    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis o

  2. In Vitro Dermal Absorption of Insensitive Munitions Explosive 101 (IMX-101) and Components (United States)


    absorption of M30A1 propellant powder (500 mg; nitroguanidine, 47.7%; nitrocellulose , 28%; nitroglycerine, 22.5%) used in the modular artillery...human skin. J Appl Toxicol 18:387-392. McDougal JN and GW Jepson. 1998. Assessment of dermal absorption potential of modified M1 propellants , WC

  3. Aging changes in skin (United States)

    ... Stress Other causes of skin changes: Allergies to plants and other substances Climate Clothing Exposures to industrial and household chemicals Indoor heating Sunlight can cause: Loss of elasticity (elastosis) ...

  4. [Skin-picking disorder]. (United States)

    Niemeier, V; Peters, E; Gieler, U


    The disorder is characterized by compulsive repetitive skin-picking (SP), resulting in skin lesions. The patients must have undertaken several attempts to reduce or stop SP. The disorder must have led to clinically significant limitations in social, professional, or other important areas of life. The symptoms cannot be better explained by another emotional disorder or any other dermatological disease. In the new DSM-V, skin-picking disorder has been included in the diagnostic system as an independent disorder and describes the self-injury of the skin by picking or scratching with an underlying emotional disorder. SP is classified among the impulse-control disorders and is, thus, differentiated from compulsive disorders as such. There are often emotional comorbidities. In cases of pronounced psychosocial limitation, interdisciplinary cooperation with a psychotherapist and/or psychiatrist is indicated.

  5. Skin picking disorder. (United States)

    Grant, Jon E; Odlaug, Brian L; Chamberlain, Samuel R; Keuthen, Nancy J; Lochner, Christine; Stein, Dan J


    Although skin picking has been documented in the medical literature since the 19th century, only now is it receiving serious consideration as a DSM psychiatric disorder in discussions for DSM-5. Recent community prevalence studies suggest that skin picking disorder appears to be as common as many other psychiatric disorders, with reported prevalences ranging from 1.4% to 5.4%. Clinical evaluation of patients with skin picking disorder entails a broad physical and psychiatric examination, encouraging an interdisciplinary approach to evaluation and treatment. Approaches to treatment should include cognitive-behavioral therapy (including habit reversal or acceptance-enhanced behavior therapy) and medication (serotonin reuptake inhibitors, N-acetylcysteine, or naltrexone). Based on clinical experience and research findings, the authors recommend several management approaches to skin picking disorder.

  6. Designing pliable structural Skins

    DEFF Research Database (Denmark)

    Tamke, Martin; Peters, Brady; Nielsen, Stig Anton;


    Structural stability can be formed through structured or seemingly unstructured approaches to fold, plead or crumble paper. This paper reports on two projects that showcase how computational design approaches can help to widen the understanding and use of structural skins....

  7. Skin or nail culture (United States)

    Mucosal culture; Culture - skin; Culture - mucosal; Nail culture; Culture - fingernail; Fingernail culture ... There, it is placed in a special dish (culture). It is then watched to see if bacteria, ...

  8. Skin, Hair, and Nails (United States)

    ... Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & Behavior School & Family Life First Aid & Safety Doctors & ... produce melanin, the pigment that gives skin its color. All people have roughly the same number of ...

  9. An elastic second skin (United States)

    Yu, Betty; Kang, Soo-Young; Akthakul, Ariya; Ramadurai, Nithin; Pilkenton, Morgan; Patel, Alpesh; Nashat, Amir; Anderson, Daniel G.; Sakamoto, Fernanda H.; Gilchrest, Barbara A.; Anderson, R. Rox; Langer, Robert


    We report the synthesis and application of an elastic, wearable crosslinked polymer layer (XPL) that mimics the properties of normal, youthful skin. XPL is made of a tunable polysiloxane-based material that can be engineered with specific elasticity, contractility, adhesion, tensile strength and occlusivity. XPL can be topically applied, rapidly curing at the skin interface without the need for heat- or light-mediated activation. In a pilot human study, we examined the performance of a prototype XPL that has a tensile modulus matching normal skin responses at low strain (<40%), and that withstands elongations exceeding 250%, elastically recoiling with minimal strain-energy loss on repeated deformation. The application of XPL to the herniated lower eyelid fat pads of 12 subjects resulted in an average 2-grade decrease in herniation appearance in a 5-point severity scale. The XPL platform may offer advanced solutions to compromised skin barrier function, pharmaceutical delivery and wound dressings.

  10. Radiation therapy -- skin care (United States)

    ... this page: // Radiation therapy - skin care To use the sharing features ... this page, please enable JavaScript. When you have radiation treatment for cancer, you may have some changes ...

  11. Allergy testing - skin (United States)

    Patch tests - allergy; Scratch tests - allergy; Skin tests - allergy; RAST test; Allergic rhinitis - allergy testing; Asthma - allergy testing; Eczema - allergy testing; Hayfever - allergy testing; Dermatitis - allergy testing; Allergy testing; ...

  12. Scalded skin syndrome (United States)

    ... Severe bloodstream infection ( septicemia ) Spread to deeper skin infection ( cellulitis ) When to Contact a Medical Professional Call your provider or go to the emergency room if you have symptoms of this disorder. Prevention ... Alternative Names Ritter disease; Staphylococcal ...

  13. Skin lesion biopsy (United States)

    ... procedure will leave a small indented area. This type of biopsy is often done when a skin cancer is ... may have stitches to close the area. This type of biopsy is often done to diagnose rashes . EXCISIONAL BIOPSY ...

  14. Spiritual and religious aspects of skin and skin disorders

    Directory of Open Access Journals (Sweden)

    Shenefelt PD


    Full Text Available Philip D Shenefelt,1 Debrah A Shenefelt2 1Dermatology and Cutaneous Surgery, University of South Florida, Tampa, 2Congregation Or Ahavah, Lutz, FL, USA Abstract: Skin and skin disorders have had spiritual aspects since ancient times. Skin, hair, and nails are visible to self and others, and touchable by self and others. The skin is a major sensory organ. Skin also expresses emotions detectable by others through pallor, coldness, "goose bumps", redness, warmth, or sweating. Spiritual and religious significances of skin are revealed through how much of the skin has been and continues to be covered with what types of coverings, scalp and beard hair cutting, shaving and styling, skin, nail, and hair coloring and decorating, tattooing, and intentional scarring of skin. Persons with visible skin disorders have often been stigmatized or even treated as outcasts. Shamans and other spiritual and religious healers have brought about healing of skin disorders through spiritual means. Spiritual and religious interactions with various skin disorders such as psoriasis, leprosy, and vitiligo are discussed. Religious aspects of skin and skin diseases are evaluated for several major religions, with a special focus on Judaism, both conventional and kabbalistic. Keywords: skin, skin disorders, spiritual, religious

  15. Skin Diseases: Cross-section of human skin (United States)

    Skip Navigation Bar Home Current Issue Past Issues Skin Diseases Cross-section of human skin Past Issues / Fall 2008 Table of Contents For ... Logical Images, Inc. I n the areas of skin health and skin diseases, the NIH's National Institute ...

  16. Mantoux Tuberculin Skin Test

    Centers for Disease Control (CDC) Podcasts


    Learn how to evaluate people for latent TB infection with the Mantoux tuberculin skin test. This podcast includes sections on administering and reading the Mantoux tuberculin skin test, the standard method for detecting latent TB infection since the 1930s.  Created: 11/22/2006 by National Center for HIV, STD and TB Prevention (NCHHSTP).   Date Released: 12/12/2006.

  17. Nicotinamide and the skin. (United States)

    Chen, Andrew C; Damian, Diona L


    Nicotinamide, an amide form of vitamin B3, boosts cellular energy and regulates poly-ADP-ribose-polymerase 1, an enzyme with important roles in DNA repair and the expression of inflammatory cytokines. Nicotinamide shows promise for the treatment of a wide range of dermatological conditions, including autoimmune blistering disorders, acne, rosacea, ageing skin and atopic dermatitis. In particular, recent studies have also shown it to be a potential agent for reducing actinic keratoses and preventing skin cancers.

  18. Have we observed the skin vibration of realistic strange stars (ReSS) ?

    CERN Document Server

    Sinha, M N; Dey, M; Ray, S; Bhowmick, S; Sinha, Monika; Dey, Jishnu; Dey, Mira; Ray, Subharthi; Bhowmick, Siddhartha


    Skin vibration of ReSS and consequent resonance absorption can account for the absorption lines in the spectrum of X-ray emission from many compact stellar objects and in particular, the stars J1210$-$5226 and RXJ1856$-$3754. Observations of the X-ray spectrum of these stars is difficult to explain, if they are neutron stars.


    Directory of Open Access Journals (Sweden)

    Shivprasad Chiplunkar


    Full Text Available The balance of dosha  represents the healthy state and imbalance will cause various diseases. In normalcy doshas will be performing their own functions and individual doshas will be having their own specific sites. By telling the various sthana of each dosha, different function that is taken up by individual dosha in different sites has been highlighted.By mentioning ‘sparshanendriyam’ as one of the sthana of vata dosha the sensory functions of skin to vata dosha has been emphasised. By mentioning ‘sparshanam’ as one of the sthana of pittadosha, the function of colouring/pigmentation of skin, which is majorly carried out  by melanocytes by secreting melanin pigment has been highlighted. Meda is one among the sthanas of kapha dosha; this can be considered as the adipose tissue of skin/below skin. Since sweda is mala of meda it can be also considered as the secretions from the eccrine glands.With respect to skin, sensory functions, both tactile and thermal is carried out by vata dosha more specifically vyana vata, pigmentation to the skin carried out by meloncytes by secreting melanin, it is nothing but function of pitta dosha more specifically brajaka pitta with the help of udana vata and finally production of sweat in sweat glands is the function of kapha. So there is the need for further study and research regarding the sthanas of all three doshas in different structures/organs in the body and its physiology.

  20. Ultraflexible organic photonic skin. (United States)

    Yokota, Tomoyuki; Zalar, Peter; Kaltenbrunner, Martin; Jinno, Hiroaki; Matsuhisa, Naoji; Kitanosako, Hiroki; Tachibana, Yutaro; Yukita, Wakako; Koizumi, Mari; Someya, Takao


    Thin-film electronics intimately laminated onto the skin imperceptibly equip the human body with electronic components for health-monitoring and information technologies. When electronic devices are worn, the mechanical flexibility and/or stretchability of thin-film devices helps to minimize the stress and discomfort associated with wear because of their conformability and softness. For industrial applications, it is important to fabricate wearable devices using processing methods that maximize throughput and minimize cost. We demonstrate ultraflexible and conformable three-color, highly efficient polymer light-emitting diodes (PLEDs) and organic photodetectors (OPDs) to realize optoelectronic skins (oe-skins) that introduce multiple electronic functionalities such as sensing and displays on the surface of human skin. The total thickness of the devices, including the substrate and encapsulation layer, is only 3 μm, which is one order of magnitude thinner than the epidermal layer of human skin. By integrating green and red PLEDs with OPDs, we fabricate an ultraflexible reflective pulse oximeter. The device unobtrusively measures the oxygen concentration of blood when laminated on a finger. On-skin seven-segment digital displays and color indicators can visualize data directly on the body.

  1. Recent Progress in Electronic Skin


    Wang, Xiandi; Dong, Lin; Zhang, Hanlu; Yu, Ruomeng; Pan, Caofeng; Wang, Zhong Lin


    The skin is the largest organ of the human body and can sense pressure, temperature, and other complex environmental stimuli or conditions. The mimicry of human skin's sensory ability via electronics is a topic of innovative research that could find broad applications in robotics, artificial intelligence, and human–machine interfaces, all of which promote the development of electronic skin (e‐skin). To imitate tactile sensing via e‐skins, flexible and stretchable pressure sensor arrays are co...

  2. Skin aging and oxidative stress


    Sayeeda Ahsanuddin; Minh Lam; Baron, Elma D.


    Skin aging occurs through two main pathways, intrinsic and extrinsic. These pathways have significant interaction in contributing to the aging phenotype, which includes skin laxity, wrinkling, pigmentation irregularities, and the appearance of neoplastic skin lesions. Here, we review the critical role that oxidative stress plays in skin aging, including its effects on signaling pathways involved in skin matrix formation and degradation, proteasome activity, as well as DNA structure. Furthermo...

  3. Skin involvement in Dupuytren's disease.


    Wade, R.; Igali, L; Figus, A


    Whether the palmar skin has a role in the development, propagation or recurrence of Dupuytren's disease remains unclear. Clinical assessment for skin involvement is difficult and its correlation with histology uncertain. We prospectively biopsied the palmar skin of consecutive patients undergoing single digit fasciectomy (for primary Dupuytren's disease without clinically involved skin) and dermofasciectomy (for clinically involved skin or recurrence) in order to investigate this relationship...

  4. Spiritual and religious aspects of skin and skin disorders (United States)

    Shenefelt, Philip D; Shenefelt, Debrah A


    Skin and skin disorders have had spiritual aspects since ancient times. Skin, hair, and nails are visible to self and others, and touchable by self and others. The skin is a major sensory organ. Skin also expresses emotions detectable by others through pallor, coldness, “goose bumps”, redness, warmth, or sweating. Spiritual and religious significances of skin are revealed through how much of the skin has been and continues to be covered with what types of coverings, scalp and beard hair cutting, shaving and styling, skin, nail, and hair coloring and decorating, tattooing, and intentional scarring of skin. Persons with visible skin disorders have often been stigmatized or even treated as outcasts. Shamans and other spiritual and religious healers have brought about healing of skin disorders through spiritual means. Spiritual and religious interactions with various skin disorders such as psoriasis, leprosy, and vitiligo are discussed. Religious aspects of skin and skin diseases are evaluated for several major religions, with a special focus on Judaism, both conventional and kabbalistic. PMID:25120377

  5. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...... learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning...

  6. The application of skin metabolomics in the context of transdermal drug delivery. (United States)

    Li, Jinling; Xu, Weitong; Liang, Yibiao; Wang, Hui


    Metabolomics is a powerful emerging tool for the identification of biomarkers and the exploration of metabolic pathways in a high-throughput manner. As an administration site for percutaneous absorption, the skin has a variety of metabolic enzymes, except other than hepar. However, technologies to fully detect dermal metabolites remain lacking. Skin metabolomics studies have mainly focused on the regulation of dermal metabolites by drugs or on the metabolism of drugs themselves. Skin metabolomics techniques include collection and preparation of skin samples, data collection, data processing and analysis. Furthermore, studying dermal metabolic effects via metabolomics can provide novel explanations for the pathogenesis of some dermatoses and unique insights for designing targeted prodrugs, promoting drug absorption and controlling drug concentration. This paper reviews current progress in the field of skin metabolomics, with a specific focus on dermal drug delivery systems and dermatosis.

  7. A two-dimensional mathematical model of percutaneous drug absorption

    Directory of Open Access Journals (Sweden)

    Kubota K


    Full Text Available Abstract Background When a drug is applied on the skin surface, the concentration of the drug accumulated in the skin and the amount of the drug eliminated into the blood vessel depend on the value of a parameter, r. The values of r depend on the amount of diffusion and the normalized skin-capillary clearence. It is defined as the ratio of the steady-state drug concentration at the skin-capillary boundary to that at the skin-surface in one-dimensional models. The present paper studies the effect of the parameter values, when the region of contact of the skin with the drug, is a line segment on the skin surface. Methods Though a simple one-dimensional model is often useful to describe percutaneous drug absorption, it may be better represented by multi-dimensional models. A two-dimensional mathematical model is developed for percutaneous absorption of a drug, which may be used when the diffusion of the drug in the direction parallel to the skin surface must be examined, as well as in the direction into the skin, examined in one-dimensional models. This model consists of a linear second-order parabolic equation with appropriate initial conditions and boundary conditions. These boundary conditions are of Dirichlet type, Neumann type or Robin type. A finite-difference method which maintains second-order accuracy in space along the boundary, is developed to solve the parabolic equation. Extrapolation in time is applied to improve the accuracy in time. Solution of the parabolic equation gives the concentration of the drug in the skin at a given time. Results Simulation of the numerical methods described is carried out with various values of the parameter r. The illustrations are given in the form of figures. Conclusion Based on the values of r, conclusions are drawn about (1 the flow rate of the drug, (2 the flux and the cumulative amount of drug eliminated into the receptor cell, (3 the steady-state value of the flux, (4 the time to reach the steady

  8. In vivo study of human skin using pulsed terahertz radiation

    Energy Technology Data Exchange (ETDEWEB)

    Pickwell, E [Semiconductor Physics Group, Cavendish Laboratory, Cambridge University, Madingley Road, Cambridge CB3 0HE (United Kingdom); Cole, B E [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom); Fitzgerald, A J [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom); Pepper, M [Semiconductor Physics Group, Cavendish Laboratory, Cambridge University, Madingley Road, Cambridge CB3 0HE (United Kingdom); Wallace, V P [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom)


    Studies in terahertz (THz) imaging have revealed a significant difference between skin cancer (basal cell carcinoma) and healthy tissue. Since water has strong absorptions at THz frequencies and tumours tend to have different water content from normal tissue, a likely contrast mechanism is variation in water content. Thus, we have previously devised a finite difference time-domain (FDTD) model which is able to closely simulate the interaction of THz radiation with water. In this work we investigate the interaction of THz radiation with normal human skin on the forearm and palm of the hand in vivo. We conduct the first ever systematic in vivo study of the response of THz radiation to normal skin. We take in vivo reflection measurements of normal skin on the forearm and palm of the hand of 20 volunteers. We compare individual examples of THz responses with the mean response for the areas of skin under investigation. Using the in vivo data, we demonstrate that the FDTD model can be applied to biological tissue. In particular, we successfully simulate the interaction of THz radiation with the volar forearm. Understanding the interaction of THz radiation with normal skin will form a step towards developing improved imaging algorithms for diagnostic detection of skin cancer and other tissue disorders using THz radiation.

  9. Mass transport model through the skin by microencapsulation system. (United States)

    Carreras, Núria; Alonso, Cristina; Martí, Meritxell; Lis, Manel J


    Skin drug delivery can be subdivided into topical and transdermal administration. Transdermal administration can take advantage of chemical and physical strategies that can improve skin permeability and allow drug penetration. In this study, the development of a skin penetration profile was carried out by an in vitro technique for a microencapsulated system of ibuprofen. Release experiments were performed using percutaneous absorption tests to determine the evolution of the principle present in each of the different skin compartments as a function of time. A general kinetic model for a microencapsulated structure as a mass transport system through the skin was applied: [Formula: see text] This model could predict the penetration profile of encapsulated substances through skin from biofunctional textiles as well as estimate the dosage profile of the active principle. The apparent diffusion coefficients found were 1.20 × 10(-7 )cm/s for the stratum corneum and higher for the rest of the skin 6.67 × 10(-6 )cm/s.

  10. Novel biodegradable porous scaffold applied to skin regeneration.

    Directory of Open Access Journals (Sweden)

    Hui-Min Wang

    Full Text Available Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments.

  11. Alkylglycerol Derivatives, a New Class of Skin Penetration Modulators

    Directory of Open Access Journals (Sweden)

    Sergio Alberto Bernal-Chávez


    Full Text Available The absorption modulating activity of two alkylglycerol derivatives (batyl and chimyl alcohol on skin barrier properties was evaluated. Biophysical tests such as transepidermal water loss (TEWL and attenuated total reflectance–Fourier transform infrared (ATR-FTIR spectroscopy, as well as in vitro skin permeation studies, were performed in order to determine the effect of these compounds as chemical absorption modulators. Four drugs were used as models: three NSAIDS (diclofenac, naproxen, and piroxicam and glycyrrhizic acid. The results showed that treatment of the skin with alkylglycerols caused (i a reduction on the amount of drug permeated; (ii a reduction in TEWL; and (iii changes in the ATR-FTIR peaks of stratum corneum lipids, indicative of a more ordered structure. All of these findings confirm that alkyl glycerols have an absorption retarding effect on the drugs tested. Such effects are expected to give rise to important applications in the pharmaceutical and cosmetic sectors, in cases where it is desirable for the drug to remain in the superficial layers of the skin to achieve a local effect.

  12. Sprayed skin turbine component (United States)

    Allen, David B


    Fabricating a turbine component (50) by casting a core structure (30), forming an array of pits (24) in an outer surface (32) of the core structure, depositing a transient liquid phase (TLP) material (40) on the outer surface of the core structure, the TLP containing a melting-point depressant, depositing a skin (42) on the outer surface of the core structure over the TLP material, and heating the assembly, thus forming both a diffusion bond and a mechanical interlock between the skin and the core structure. The heating diffuses the melting-point depressant away from the interface. Subsurface cooling channels (35) may be formed by forming grooves (34) in the outer surface of the core structure, filling the grooves with a fugitive filler (36), depositing and bonding the skin (42), then removing the fugitive material.

  13. Extreme skin depth waveguides

    CERN Document Server

    Jahani, Saman


    Recently, we introduced a paradigm shift in light confinement strategy and introduced a class of extreme skin depth (e-skid) photonic structures (S. Jahani and Z. Jacob, "Transparent sub-diffraction optics: nanoscale light confinement without metal," Optica 1, 96-100 (2014)). Here, we analytically establish that figures of merit related to light confinement in dielectric waveguides are fundamentally tied to the skin depth of waves in the cladding. We contrast the propagation characteristics of the fundamental mode of e-skid waveguides and conventional waveguides to show that the decay constant in the cladding is dramatically larger in e-skid waveguides, which is the origin of sub-diffraction confinement. Finally, we propose an approach to verify the reduced skin depth in experiment using the decrease in the Goos-H\\"anchen phase shift.

  14. Skin Cancer Detection

    Directory of Open Access Journals (Sweden)

    N. Durga Rao


    Full Text Available : In recent days, skin cancer is seen as one of the most Hazardous form of the Cancers found in Humans. Skin cancer is found in various types such as Melanoma, Basal and Squamous cell Carcinoma among which Melanoma is the most unpredictable. The detection of Melanoma cancer in early stage can be helpful to cure it. Computer vision can play important role in Medical Image Diagnosis and it has been proved by many existing systems. In this paper, we present a survey on different steps which are being to detect the Melanoma Skin Cancer using Image Processing tools. In every step, what are the different methods are be included in our paper

  15. Smoking and skin disease

    DEFF Research Database (Denmark)

    Thomsen, S F; Sørensen, L T


    Tobacco smoking is a serious and preventable health hazard that can cause or exacerbate a number of diseases and shorten life expectancy, but the role of smoking as an etiologic factor in the development of skin disease is largely unknown. Although epidemiological evidence is sparse, findings...... suggest that tobacco smoking is a contributing factor in systemic lupus erythematosus, psoriasis, palmoplantar pustulosis, cutaneous squamous cell carcinoma, hidradenitis suppurativa, and genital warts. In contrast, smoking may confer some protective effects and mitigate other skin diseases, notably...... pemphigus vulgaris, pyoderma gangrenosum, aphthous ulcers, and Behçet's disease. Various degenerative dermatologic conditions are also impacted by smoking, such as skin wrinkling and dysregulated wound healing, which can result in post-surgical complications and delayed or even arrested healing of chronic...

  16. Transdermal nicotine absorption handling e-cigarette refill liquids. (United States)

    Maina, Giovanni; Castagnoli, Carlotta; Passini, Valter; Crosera, Matteo; Adami, Gianpiero; Mauro, Marcella; Filon, Francesca Larese


    The concentrated nicotine in e-cigarette refill liquids can be toxic if inadvertently ingested or absorbed through the skin. Reports of poisonings due to accidental ingestion of nicotine on refill liquids are rapidly increasing, while the evaluation of nicotine dermally absorbed still lacks. For that reason we studied transdermal nicotine absorption after the skin contamination with e-liquid. Donor chambers of eight Franz diffusion cells were filled with 1 mL of 0.8 mg/mL nicotine e-liquid for 24 h. The concentration of nicotine in the receiving phase was determined by high-performance liquid chromatography (LOD:0.1 μg/mL). Nicotine was detectable in receiving solution 2 h after the start of exposure and increased progressively. The medium flux calculated was 4.82 ± 1.05 μg/cm(2)/h with a lag time of 3.9 ± 0.1 h. After 24 h, the nicotine concentration in the receiving compartment was 101.02 ± 22.35 μg/cm(2) corresponding to 3.04 mg of absorbed nicotine after contamination of a skin surface of 100 cm(2). Skin contamination with e-liquid can cause nicotine skin absorption: caution must be paid when handling refill e-liquids.

  17. Skin tears: prevention and treatment. (United States)

    Wick, Jeannette Y; Zanni, Guido R


    While skin tears are common among the elderly in general, and residents of long-term care facilities in particular, there has been limited research into their treatment. Many facilities voluntarily track skin tears, and some states require facilities to report these events. Risk factors include age, xerosis (abnormal eye, skin, or mouth dryness), need for help in activities of daily living, presence of senile purpura, visual impairment, and poor nutrition. Plans to prevent skin tears that employ skin sleeves, padded side rails, gentle skin cleansers, moisturizing lotions, as well as staff education, can decrease by half the number of skin tears incurred in a long-term care facility. Although the treatment process seems simple, it is time consuming and can be painful for the patient. Residents with dementia or agitation often try to remove bulky dressings used to cover skin tears. Dressing changes may injure the fragile wound via skin stripping.

  18. Skin innate immune system

    Directory of Open Access Journals (Sweden)

    Berna Aksoy


    Full Text Available All multicellular organisms protect themselves from external universe and microorganisms by innate immune sytem that is constitutively present. Skin innate immune system has several different components composed of epithelial barriers, humoral factors and cellular part. In this review information about skin innate immune system and its components are presented to the reader. Innate immunity, which wasn’t adequately interested in previously, is proven to provide a powerfull early protection system, control many infections before the acquired immunity starts and directs acquired immunity to develop optimally

  19. About Skin-to-Skin Care (Kangaroo Care) (United States)

    ... Size Email Print Share About Skin-to-Skin Care Page Content Article Body You may be able ... care, also called kangaroo care. What is Kangaroo Care? Kangaroo care was developed in South America as ...

  20. Central cooling: absorptive chillers

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.


    This technology evaluation covers commercially available single-effect, lithium-bromide absorption chillers ranging in nominal cooling capacities of 3 to 1,660 tons and double-effect lithium-bromide chillers from 385 to 1,060 tons. The nominal COP measured at operating conditions of 12 psig input steam for the single-effect machine, 85/sup 0/ entering condenser water, and 44/sup 0/F exiting chilled-water, ranges from 0.6 to 0.65. The nominal COP for the double-effect machine varies from 1.0 to 1.15 with 144 psig entering steam. Data are provided to estimate absorption-chiller performance at off-nominal operating conditions. The part-load performance curves along with cost estimating functions help the system design engineer select absorption equipment for a particular application based on life-cycle costs. Several suggestions are offered which may be useful for interfacing an absorption chiller with the remaining Integrated Community Energy System. The ammonia-water absorption chillers are not considered to be readily available technology for ICES application; therefore, performance and cost data on them are not included in this evaluation.

  1. Preventing Skin Cancer

    Centers for Disease Control (CDC) Podcasts


    A man and a woman talk about how they’ve learned to protect their skin from the sun over the years. .  Created: 5/18/2016 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 5/18/2016.

  2. Cryoglobulin induced skin ulceration

    Directory of Open Access Journals (Sweden)

    Fatima Razvi


    Full Text Available Lupus Erythematosus (LE is a multi-organ auto-immune disease which results from complex interaction of genetic and environmental factors. The clinical spectrum ranges from minor cutaneous lesions to life threatening multi-organ dysfunction. The skin manifestations are variable and common and range from LE specific to LE non-specific cutaneous disease. Vasculitis is one of the most common non-specific skin lesion of Systemic lupus erythematosus (SLE and appears as purpuric lesions, infarcts along lateral nail folds, peripheral gangrene, sub-cutaneous nodules and ulcers. Mixed cryoglobulinaemia (type II is associated with connective tissue disorders including SLE. Skin manifestations are seen in 60-100% patients and are more common in females. The most common manifestation is palpable purpura of lower extremities seen in 30-100% which often is triggered in winter or on cold exposure. Skin infarction, hemorrhagic crusts and ulcers are seen in 25% of patients. Wide spread necrotic ulcers are seen in 10-25% of patients which are often exacerbated by cold.

  3. Tuberculin Skin Testing (United States)

    ... the Facts Tuberculosis - The Connection between TB and HIV 12-Dose Regimen for Latent TB Infection-Patient Education Brochure Posters Mantoux Tuberculin Skin Test Wall Chart World TB Day Think TB Stop TB Reports & Articles Morbidity and Mortality Weekly Reports (MMWRs) DTBE Authored ...

  4. Immunopathology of skin lesions

    Directory of Open Access Journals (Sweden)

    Khan Nazoora


    Full Text Available A study was conducted on 130 patients suffering from skin lesions which included psoriasis, lichen planus, DLE, pemphigus, vitiligo and alopecia areata. Forty age-and-sex-matched healthy individuals served as control. Serum IgG, IgM, and circulating immune complexes (CIC were estimated. Significant increase in serum IgG (1937.2 ± 1030.43 mg% and IgM (232.12 ± 136.98 mg% was observed in all the skin lesions when compared with controls except in lichen planus where they were significantly lowered, values being 580.61± 77.35 mg% and 66.88 ± 6.59mg% respectively. CIC levels were significantly raised (P<0.00 1 in various skin lesions (40.49±23.29 when compared with controls (17.68± 3.21, but no significance was observed in lichen planus( 17.72 ± 4.28. Serum IgG, IgM and CIC were statistically significantly altered depending on the extent of the lesion and lowered significantly to almost normal values following treatment, thereby confirming the role of immunity in the pathogenesis of these skin disorders.

  5. Coumarin derivatives, but not coumarin itself, cause skin irritation via topical delivery. (United States)

    Pan, Tai-Long; Wang, Pei-Wen; Aljuffali, Ibrahim A; Leu, Yann-Lii; Hung, Yi-Yun; Fang, Jia-You


    Coumarin and its derivatives are widely employed as a fragrance in cosmetics and skin care products. The skin absorption level and possible disruption to the skin by topical application of coumarins were evaluated in this study. Percutaneous absorption of osthole, daphnoretin, coumarin, byakangelicin, and 7-hydroxycoumarin was assessed in vitro and in vivo. Skin physiology measurements and immunoblotting were utilized as methodologies for validating toxicity. The relationship between structures and permeation/toxicity of coumarins was elucidated. Both equimolar concentration and saturated solubility in 30% ethanol were used as the applied dose. Osthole with the most lipophilic characteristic demonstrated the greatest skin accumulation, followed by coumarin and 7-hydroxycoumarin. Coumarin was the permeant with the highest flux across the skin. The trend of in vivo deposition was consistent with that of the in vitro profiles. Skin uptake of osthole was 8-fold higher than that of coumarin. Hair follicles played a significant role as a pathway for transport of coumarin according to the examination of follicular accumulation. Osthole and 7-hydroxycoumarin slightly, but significantly, enhanced transepidermal water loss after a consecutive 5-day administration. The immunoblotting profiling verified the role of proliferation in skin damage induced by osthole, byakangelicin, and 7-hydroxycoumarin. The proliferation-related proteins examined in this work included glucose-regulated proteins, cytokeratin, and C-myc. Daphnoretin and coumarin showed a negligible alteration on protein biomarkers. The experimental results suggested that skin irritation caused by coumarins was mainly derived from the analogs but not from coumarin itself.

  6. Further development of an in vitro model for studying the penetration of chemicals through compromised skin. (United States)

    Davies, Diane J; Heylings, Jon R; Gayes, Heather; McCarthy, Timothy J; Mack, M Catherine


    A new in vitro model based on the electrical resistance properties of the skin barrier has been established in this laboratory. The model utilises a tape stripping procedure in dermatomed pig skin that removes a specific proportion of the stratum corneum, mimicking impaired barrier function observed in humans with damaged skin. The skin penetration and distribution of chemicals with differing physicochemical properties, namely; Benzoic acid, 3-Aminophenol, Caffeine and Sucrose has been assessed in this model. Although, skin penetration over 24h differed for each chemical, compromising the skin did not alter the shape of the time course profile, although absorption into receptor fluid was higher for each chemical. Systemic exposure (receptor fluid, epidermis and dermis), was marginally higher in compromised skin following exposure to the fast penetrant, Benzoic acid, and the slow penetrant Sucrose. The systemically available dose of 3-Aminophenol increased to a greater extent and the absorption of Caffeine was more than double in compromised skin, suggesting that Molecular Weight and Log Pow, are not the only determinants for assessing systemic exposure under these conditions. Although further investigations are required, this in vitro model may be useful for prediction of dermal route exposure under conditions where skin barrier is impaired.

  7. Percutaneous absorption enhancers: mechanisms and potential

    Directory of Open Access Journals (Sweden)

    Letícia Norma Carpentieri-Rodrigues


    Full Text Available Transdermal applications of drugs present many advantages in terms of absorption, however this is not easily obtained through the transdermal route. The principle barrier is the stratum corneum and one of the strategies that have been found to promote cutaneous drug penetration is through the use of absorption enhancers. Many substances have been identified as absorption enhancers. Although the list of substances that promote absorption is growing, in most cases, there is a direct correlation between the effects of absorption enhancers and their skin toxicity. The use of these substances depends therefore on studies which focus on local and systemic toxicity, as well as action mechanisms.A via transdérmica para a absorção de fármacos apresenta várias vantagens, porém a absorção através desta via não é fácil de ser obtida. A principal barreira encontrada é o estrato córneo e uma das estratégias encontradas para promover a permeação cutânea de fármacos é o uso de promotores de absorção. Há uma variedade de substâncias identificadas como promotores de absorção. Enquanto a lista de substâncias de promotores de absorção percutânea vem aumentando, na maioria dos casos, há uma correlação entre o efeito promotor e a toxicidade para a pele. O emprego destas substâncias depende, portanto, de estudos enfocando a toxicidade local e sistêmica, bem como o mecanismo de ação.

  8. Skin color independent assessment of aging using skin autofluorescence

    NARCIS (Netherlands)

    Koetsier, M.; Nur, E.; Chunmao, H.; Lutgers, H.L.; Links, T.P.; Smit, A.J.; Rakhorst, G.; de Graaff, R.


    Skin autofluorescence (AF) for the non-invasive assessment of the amount of accumulated tissue Advanced Glycation Endproducts (AGEs) increases with aging. In subjects with darker skin colors, measurements typically result in lower AF values than in subjects with fair skin colors, e. g. due to select

  9. Vascular aspects of water uptake mechanisms in the toad skin: perfusion, diffusion, confusion

    DEFF Research Database (Denmark)

    Willumsen, Niels; Viborg, Arne L; Hillyard, Stanley D


    Blood cell flow (BCF) in the water absorbing "seat patch" region of toad skin was measured with laser Doppler flow cytometry. BCF of dehydrated toads increased by a factor of 6-8 when water contact was made and declined gradually as toads rehydrated. Water absorption was initially stimulated...... and declined in parallel with BCF. Water absorption measured during the initial rehydration period did not correlate with BCF and hydrated toads injected with AVT increased water absorption without an increase in BCF indicating the lack of an obligate relation between blood flow and water absorption...... coupling explains the greater absorption from dilute salt solutions. Rehydration from 10 mM CaCl2 was stimulated above that of DI water by a similar degree as with 50 mM NaCl suggesting the anion might control water permeability of the skin....


    Directory of Open Access Journals (Sweden)

    Kazi Tanvir Ahmed Siddiqui


    Full Text Available The increasing popularity of animes makes it vulnerable to unwanted usages like copyright violations and pornography. That’s why, we need to develop a method to detect and recognize animation characters. Skin detection is one of the most important steps in this way. Though there are some methods to detect human skin color, but those methods do not work properly for anime characters. Anime skin varies greatly from human skin in color, texture, tone and in different kinds of lighting. They also vary greatly among themselves. Moreover, many other things (for example leather, shirt, hair etc., which are not skin, can have color similar to skin. In this paper, we have proposed three methods that can identify an anime character’s skin more successfully as compared with Kovac, Swift, Saleh and Osman methods, which are primarily designed for human skin detection. Our methods are based on RGB values and their comparative relations.

  11. Tissue Engineered Human Skin Equivalents

    Directory of Open Access Journals (Sweden)

    Zheng Zhang


    Full Text Available Human skin not only serves as an important barrier against the penetration of exogenous substances into the body, but also provides a potential avenue for the transport of functional active drugs/reagents/ingredients into the skin (topical delivery and/or the body (transdermal delivery. In the past three decades, research and development in human skin equivalents have advanced in parallel with those in tissue engineering and regenerative medicine. The human skin equivalents are used commercially as clinical skin substitutes and as models for permeation and toxicity screening. Several academic laboratories have developed their own human skin equivalent models and applied these models for studying skin permeation, corrosivity and irritation, compound toxicity, biochemistry, metabolism and cellular pharmacology. Various aspects of the state of the art of human skin equivalents are reviewed and discussed.

  12. Eldercare at Home: Skin Problems (United States)

    ... disorders that give rise to serious medical problems. Older skin is less oily, less elastic, and thinner. It ... of old age." Response Yes, it is true older skin is less oily and it is thinner than ...

  13. Skin - abnormally dark or light (United States)

    ... ency/article/003242.htm Skin - abnormally dark or light To use the sharing features on this page, ... the hands. The bronze color can range from light to dark (in fair-skinned people) with the ...

  14. Maintaining Healthy Skin -- Part 2 (United States)

    ... from seams or elastic binding. Check also for blisters, bumps, insect bites, dry flaky skin or pimples. ... always check your skin carefully after wearing new shoes or clothing. Too loose — Loose clothing can form ...

  15. The management of skin tears. (United States)

    Meuleneire, Frans

    During the ageing process the layers of the skin start to atrophy; the epidermis becomes thin and fragile, and dermal thickness decreases by 20 per cent (White et al, 1994). This makes skin tears a common problem among older people.

  16. Staining of skin with dihydroxyacetone. (United States)



    The reaction of skin with dihydroxyacetone to produce a brown "artificial tan" appears to proceed through combination with free amino groups in skin proteins, and particularly by combination of dihydroxyacetone with the free guanido group in arginine.

  17. Mixture component effects on the in vitro dermal absorption of pentachlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Riviere, J.E.; Qiao, G.; Baynes, R.E.; Brooks, J.D. [Coll. of Veterinary Medicine, North Carolina State Univ., Raleigh, NC (United States); Mumtaz, M. [Agency for Toxic Substances and Disease Registry (ATSDR), Atlanta, GA (United States)


    Interactions between chemicals in a mixture and interactions of mixture components with the skin can significantly alter the rate and extent of percutaneous absorption, as well as the cutaneous disposition of a topically applied chemical. The predictive ability of dermal absorption models, and consequently the dermal risk assessment process, would be greatly improved by the elucidation and characterization of these interactions. Pentachlorophenol (PCP), a compound known to penetrate the skin readily, was used as a marker compound to examine mixture component effects using in vitro porcine skin models. PCP was administered in ethanol or in a 40% ethanol/60% water mixture or a 40% ethanol/60% water mixture containing either the rubefacient methyl nicotinate (MNA) or the surfactant sodium lauryl sulfate (SLS), or both MNA and SLS. Experiments were also conducted with {sup 14}C-labelled 3,3',4,4'-tetrachlorobiphenyl (TCB) and 3,3',4,4',5-pentachlorobiphenyl (PCB). Maximal PCP absorption was 14.12% of the applied dose from the mixture containing SLS, MNA, ethanol and water. However, when PCP was administered in ethanol only, absorption was only 1.12% of the applied dose. There were also qualitative differences among the absorption profiles for the different PCP mixtures. In contrast with the PCP results, absorption of TCB or PCB was negligible in perfused porcine skin, with only 0.14% of the applied TCB dose and 0.05% of the applied PCB dose being maximally absorbed. The low absorption levels for the PCB congeners precluded the identification of mixture component effects. These results suggest that dermal absorption estimates from a single chemical exposure may not reflect absorption seen after exposure as a chemical mixture and that absorption of both TCB and PCB are minimal in this model system. (orig.)

  18. Nicotinamide for skin cancer chemoprevention. (United States)

    Damian, Diona L


    Nicotinamide (vitamin B3 ) has a range of photoprotective effects in vitro and in vivo; it enhances DNA repair, reduces UV radiation-induced suppression of skin immune responses, modulates inflammatory cytokine production and skin barrier function and restores cellular energy levels after UV exposure. Pharmacological doses of nicotinamide have been shown to reduce actinic keratoses and nonmelanoma skin cancer incidence in high-risk individuals, making this a nontoxic and accessible option for skin cancer chemoprevention in this population.



    S. Ramya Silpa; Chidvila V


    Skin cancer can be of 2 types mainly. They are malignant melanoma and non-malignant melanoma. Skin cancer mainly occurs due to exposure of sunlight. Ozone depletion and chemical exposures are other factors involved in precipitating skin cancer. Mutations of p53 gene are involved in UV- induced carcinogenesis. P53 gene acts vital in development of SCC. So, prevention of skin cancer is the main criteria. Regular application of sunscreens could be one of the primary prevention. The purpose of pr...

  20. Skin cancer: Etiology and management. (United States)

    Qadir, Muhammad Imran


    Nowadays, occurrence of skin cancer is very common in humans. It is reported that the most common cause of the skin cancer is excessive exposure to sunlight as it contains harmful radiations; the ultra violet rays. Different management strategies are used for different types of skin cancers, which are chemotherapy, radiation therapy.

  1. Skin Pedagogies and Abject Bodies (United States)

    Kenway, Jane; Bullen, Elizabeth


    How does the beauty industry "narrate the skin"? What does it teach women from different cultural groups about the female body? How does skin function as a site where female subjection and abjection are produced and reproduced? In this paper we examine the skin industry pointing to its extreme commodification of the female body and to the…

  2. Comparison of atmospheric microplasma and plasma jet irradiation for increasing of skin permeability (United States)

    Shimizu, K.; Tran, N. A.; Hayashida, K.; Blajan, M.


    Atmospheric plasma is attracting interest for medical applications such as sterilization, treatment of cancer cells and blood coagulation. Application of atmospheric plasma in dermatology has potential as a novel tool for wound healing, skin rejuvenation and treatment of wrinkles. In this study, we investigated the enhancement of percutaneous absorption of dye as alternative agents of transdermal drugs. Hypodermic needles are often the only way to deliver large-molecule drugs into the dermis, although a safe transdermal drug delivery method that does not require needles would be desirable. We therefore explored the feasibility of using atmospheric microplasma irradiation to enhance percutaneous absorption of drugs, as an alternative delivery method to conventional hypodermic needles. Pig skin was used as a biological sample, exposed to atmospheric microplasma, and analyzed by attenuated total reflection-Fourier transform infrared spectroscopy. A tape stripping test, a representative method for evaluating skin barrier performance, was also conducted for comparison. Transepidermal water loss (TEWL) was measured and compared with and without atmospheric microplasma irradiation, to quantify water evaporation from the inner body through the skin barrier. The results show that the stratum corneum, the outermost skin layer, could be chemically and physically modified by atmospheric microplasma irradiation. Physical damage to the skin by microplasma irradiation and an atmospheric plasma jet was also assessed by observing the skin surface. The results suggest that atmospheric microplasma has the potential to enhance percutaneous absorption.

  3. In vitro permeation and disposition of niacinamide in silicone and porcine skin of skin barrier-mimetic formulations. (United States)

    Haque, Tasnuva; Lane, Majella E; Sil, Bruno C; Crowther, Jonathan M; Moore, David J


    Niacinamide (NIA) is an amide form of vitamin B3 which is used in cosmetic formulations to improve various skin conditions and it has also been shown to increase stratum corneum thickness following repeated application. In this study, three doses (5, 20 and 50μL per cm(2)) of two NIA containing oil-in-water skin barrier-mimetic formulations were evaluated in silicone membrane and porcine ear skin and compared with a commercial control formulation. Permeation studies were conducted over 24h in Franz cells and at the end of the experiment membranes were washed and niacinamide was extracted. For the three doses, retention or deposition of NIA was generally higher in porcine skin compared with silicone membrane, consistent with the hydrophilic nature of the active. Despite the control containing a higher amount of active, comparable amounts of NIA were deposited in skin for all formulations for all doses; total skin absorption values (permeation and retention) of NIA were also comparable across all formulations. For infinite (50μL) and finite (5μL) doses the absolute permeation of NIA from the control formulation was significantly higher in porcine skin compared with both test formulations. This likely reflects differences in formulation components and/or presence of skin penetration enhancers in the formulations. Higher permeation for the 50 and 20μL dose was also evident in porcine skin compared with silicone membrane but the opposite is the case for the finite dose. The findings point to the critical importance of dose and occlusion when evaluating topical formulations in vitro and also the likelihood of exaggerated effects of excipients on permeation at infinite and pseudo-finite dose applications.

  4. Pre-treatment effects of trichloroethylene on the dermal absorption of the biocide, triazine. (United States)

    Baynes, Ronald E; Yeatts, James L; Brooks, James D; Riviere, Jim E


    Triazine is often added to cutting-fluid formulations in the metal-machining industry as a preservative. Trichloroethylene (TCE) is a solvent used for cleaning the cutting fluid or oil from the metal product. The purpose of this study was to examine the effect of TCE on the dermal absorption of triazine in an in vitro flow-through diffusion cell system. Skin sections were dosed topically with aqueous mixtures containing mineral oil or polyethylene glycol (PEG) spiked with (14)C-triazine. Some skin sections were simultaneously exposed to TCE while other skin sections were pre-treated with TCE daily for 4 days in vivo and then exposed to these mixtures in vitro. TCE pre-treatment almost doubled triazine permeability, but this pre-treatment had no effect on triazine diffusivity. The pre-treatment effects of TCE on triazine permeability appear to be more important in PEG-based mixtures than in the mineral oil-based mixtures. Simultaneous single exposure to TCE had little or no effect on triazine absorption. TCE absorption was significantly less than triazine absorption; however, cutting fluid additives had a more significant effect on TCE absorption than on triazine absorption. In summary, this study demonstrated that TCE pre-treatment can significantly alter the dermal permeability to triazine, and workers who are chronically exposed to this or similar cleansers may be at increased risk of absorbing related skin irritants.

  5. Melanin and blood concentration in human skin studied by multiple regression analysis: experiments (United States)

    Shimada, M.; Yamada, Y.; Itoh, M.; Yatagai, T.


    Knowledge of the mechanism of human skin colour and measurement of melanin and blood concentration in human skin are needed in the medical and cosmetic fields. The absorbance spectrum from reflectance at the visible wavelength of human skin increases under several conditions such as a sunburn or scalding. The change of the absorbance spectrum from reflectance including the scattering effect does not correspond to the molar absorption spectrum of melanin and blood. The modified Beer-Lambert law is applied to the change in the absorbance spectrum from reflectance of human skin as the change in melanin and blood is assumed to be small. The concentration of melanin and blood was estimated from the absorbance spectrum reflectance of human skin using multiple regression analysis. Estimated concentrations were compared with the measured one in a phantom experiment and this method was applied to in vivo skin.

  6. Three-dimensional multispectral optoacoustic mesoscopy reveals melanin and blood oxygenation in human skin in vivo. (United States)

    Schwarz, Mathias; Buehler, Andreas; Aguirre, Juan; Ntziachristos, Vasilis


    Optical imaging plays a major role in disease detection in dermatology. However, current optical methods are limited by lack of three-dimensional detection of pathophysiological parameters within skin. It was recently shown that single-wavelength optoacoustic (photoacoustic) mesoscopy resolves skin morphology, i.e. melanin and blood vessels within epidermis and dermis. In this work we employed illumination at multiple wavelengths for enabling three-dimensional multispectral optoacoustic mesoscopy (MSOM) of natural chromophores in human skin in vivo operating at 15-125 MHz. We employ a per-pulse tunable laser to inherently co-register spectral datasets, and reveal previously undisclosed insights of melanin, and blood oxygenation in human skin. We further reveal broadband absorption spectra of specific skin compartments. We discuss the potential of MSOM for label-free visualization of physiological biomarkers in skin in vivo.

  7. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj


    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  8. Iron deposition in skin of patients with haemochromatosis

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, T. E-mail:; Silva, J.N.; Alves, L.C.; Filipe, P


    Haemochromatosis is the most common inherited liver disease in Caucasians and the most common autosomal recessive genetic disorder. It is characterized by inappropriately high iron absorption resulting in progressive iron overload in parenchymal organs such as liver, heart, pancreas, pituitary, joints, and skin. Upon early detection, haemochromatosis can be a manageable chronic disease but, if undetected, is potentially fatal. Skin biopsies were obtained from patients and from healthy donors. Images of the elemental distributions in skin were obtained using nuclear microscopy techniques (nuclear microprobe, NMP). Elemental profiles along skin, and intra-, and extra-cellular iron concentrations, were determined. Results for patients with haemochromatosis were cross-examined with morphologic features and with data obtained for healthy skin. Skin iron content is much increased in patients with haemochromatosis when compared with healthy subjects. Extensive iron deposits are observed at dermis, at the dermo-epidermal interface, at upper epidermis layers and at stratum corneum. Iron deposition was observed preferentially at cell boundaries or at the interstitial matrix.

  9. Serotonin in human skin

    Institute of Scientific and Technical Information of China (English)

    Jianguo Huang; Qiying Gong; Guiming Li


    In this review the authors summarize data of a potential role for serotonin in human skin physiology and pathology. The uncovering of endogenous serotonin synthesis and its transformation to melatonin underlines a putative important role of this pathway in melanocyte physiology and pathology. Pathways of the biosynthesis and biodegradation of serotonin have been characterized in human beings and its major cellular populations. Moreover, receptors of serotonin are expressed on keratinocytes, melanocytes, and fibroblasts and these mediate phenotypic actions on cellular proliferation and differentiation. And the widespread expression of a cutaneous seorotoninergic system indicates considerable selectivity of action to facilitate intra-, auto-, or paracrine mechanisms that define and influence skin function in a highly compartmentalized manner. Melatonin, in turn, can also act as a hormone, neurotransmitter, cytokine, biological modifier and immunomodulator. Thus, Serotonin local synthesis and cellular localization could thus become of great importance in the diagnosis and management of cutaneous pathology.

  10. Skin contamination dosimeter (United States)

    Hamby, David M.; Farsoni, Abdollah T.; Cazalas, Edward


    A technique and device provides absolute skin dosimetry in real time at multiple tissue depths simultaneously. The device uses a phoswich detector which has multiple scintillators embedded at different depths within a non-scintillating material. A digital pulse processor connected to the phoswich detector measures a differential distribution (dN/dH) of count rate N as function of pulse height H for signals from each of the multiple scintillators. A digital processor computes in real time from the differential count-rate distribution for each of multiple scintillators an estimate of an ionizing radiation dose delivered to each of multiple depths of skin tissue corresponding to the multiple scintillators embedded at multiple corresponding depths within the non-scintillating material.

  11. Double-Skin Facade

    DEFF Research Database (Denmark)

    Kalyanova, Olena

    difficulties experienced by scientists when attempting to model DSF thermal and energy performance were examined. In addition, the lack of experimental studies and empirical validation of models was realized, many numerical models have not been empirically validated and most of them require an expert knowledge...... IEA Annex 34/43, subtask E "Double-Skin Facade". The results of empirical validation are discussed in this work. Discussion and analysis of experimental results is carried out. It has lead to hypothesis of recirculation flow phenomenon in the DSF cavity. Finally, a suggestion of a new numerical model......Double-Skin Facades (DSF) are gaining popularity that, in fact, appears to be independent from sturdy critics of the concept in the past years. DSF buildings are being built in Europe and worldwide, DSF concept is being taught at schools of architecture and fully glazed office buildings are being...

  12. Skin Cancer: Biology, Risk Factors & Treatment (United States)

    ... turn Javascript on. Feature: Skin Cancer Skin Cancer: Biology, Risk Factors & Treatment Past Issues / Summer 2013 Table ... Articles Skin Cancer Can Strike Anyone / Skin Cancer: Biology, Risk Factors & Treatment / Timely Healthcare Checkup Catches Melanoma ...

  13. Skin changes in menopause. (United States)

    Bolognia, J L; Braverman, I M; Rousseau, M E; Sarrel, P M


    Skin signs and symptoms were examined in 46 menopausal women prior to estrogen replacement therapy. Several symptoms such as pruritus, bruising, dryness and thinning were seen more frequently in sun-exposed skin emphasizing the contribution of photoaging. At the end of a 6-mth treatment period, no significant difference was observed in the prevalence or severity of the cutaneous signs and symptoms when patients receiving transdermal 17 beta-estradiol (Estraderm) were compared with controls (the only exception was cutaneous flushing). Elastic fibers from sun-protected (buttock) skin of menopausal women were studied by light and electron microscopy. In 3 women (ages 30-37) with a history of premature menopause, the elastic fibers had several degenerative changes including coalescence of cystic spaces into lacunae, peripheral fragmentation, granular degeneration and splitting of the fibers into strands. Similar age-related ultrastructural changes are normally found in individuals that are at least 20 yrs older than these patients. These findings are suggestive of a relationship between premature aging of the dermal elastic fibers and estrogen deprivation.


    Directory of Open Access Journals (Sweden)

    Herry Irawan


    Full Text Available Dental panoramic radiograph in Indonesia has been widely used. Modern diagnostic imaging equipment with minimum radiation is still very limited. One of the conditions in nuclear safety law, UU 10/1997, is an optimization of all radiation sources with DRL through skin dose measurements. In Indonesia, the national DRL has not been established yet, and there were no reports on the study of panoramic skin dose in Indonesia. The aim of this preliminary study was to obtain a panoramic skin dose radiation as reference to establish DRL in Indonesia. Panoramic radiographs of sixteen female and fifteen male patients, aged 4 – 48 years, were taken using the standard conventional method, with TLD chips attached in location groups. The chips were then read with the detector and integrator of BATAN, in high and low temperature condition at the same time. It was revealed that behind the right and left ear were the regions with the highest radiation dose received, followed by the back of the neck, left jaw, right jaw, and chin. The result of this study has shown the importance of DRL in Indonesia since the use of modern diagnostic imaging equipement that limits radiation dose to the minimum level is still very limited.

  15. Development of human skin equivalents to unravel the impaired skin barrier in atopic dermatitis skin

    NARCIS (Netherlands)

    Eweje, M.O.


    The studies in this thesis describes the barrier defects in Atopic Dermatitis (AD) skin and various techniques to develop AD Human Skin Equivalents (HSEs) which can be used to better understand the role of several factors in the pathogenesis of AD skin. The results described show that Inflammation p

  16. TXA497 as a topical antibacterial agent: comparative antistaphylococcal, skin deposition, and skin permeation studies with mupirocin. (United States)

    Dorrani, Mania; Kaul, Malvika; Parhi, Ajit; LaVoie, Edmond J; Pilch, Daniel S; Michniak-Kohn, Bozena


    TXA497 is representative of a new class of guanidinomethyl biaryl compounds that exhibit potent bactericidal behavior against methicillin-resistant Staphylococcus aureus (MRSA). In this study, we compared the anti-staphylococcal, skin deposition, and skin permeation properties of TXA497 and the topical anti-MRSA antibiotic mupirocin. The results of minimum inhibitory concentration (MIC) assays revealed that TXA497 retains potent activity against MRSA that is highly resistant to mupirocin. Using Franz diffusion cells, compound deposition into human cadaver skin was evaluated, and the results showed the skin deposition of TXA497 to be significantly greater than that of mupirocin. Moreover, unlike mupirocin, TXA497 does not pass through the entire skin layer, suggesting a minimal potential for the systemic absorption of the compound upon topical administration. Additionally, antibacterial concentrations of TXA497 showed no significant toxicity to primary human keratinocytes. Given the rising levels of mupirocin resistance among MRSA populations, our results are significant in that they highlight TXA497 as a potentially useful alternative therapy for treating MRSA skin infections that are resistant to mupirocin.

  17. Photothermal Radiometry for Skin Research

    Directory of Open Access Journals (Sweden)

    Perry Xiao


    Full Text Available Photothermal radiometry is an infrared remote sensing technique that has been used for skin and skin appendages research, in the areas of skin hydration, hydration gradient, skin hydration depth profiling, skin thickness measurements, skin pigmentation measurements, effect of topically applied substances, transdermal drug delivery, moisture content of bio-materials, membrane permeation, and nail and hair measurements. Compared with other technologies, photothermal radiometry has the advantages of non-contact, non-destructive, quick to make a measurement (a few seconds, and being spectroscopic in nature. It is also colour blind, and can work on any arbitrary sample surfaces. It has a unique depth profiling capability on a sample surface (typically the top 20 µm, which makes it particularly suitable for skin measurements. In this paper, we present a review of the photothermal radiometry work carried out in our research group. We will first introduce the theoretical background, then illustrate its applications with experimental results.

  18. Terapia fotodinâmica com ftalocianina de zinco tópica: avaliação da intensidade de fluorescência, absorção cutânea, alterações histológicas e imuno-histoquímicas na pele do modelo animal Topical photodynamic therapy with zinc phthalocyanine: evaluation of fluorescence intensity, skin absorption, skin histological and immunohistochemical changes in animal model

    Directory of Open Access Journals (Sweden)

    Marília Vannuchi Tomazini


    Full Text Available FUNDAMENTOS - Ftalocianinas são promissores agentes fotossensibilizadores na terapia fotodinâmica (TFD. OBJETIVOS - Avaliar intervalos, veículos e a incorporação de promotor de absorção na formulação tópica da ftalocianina de zinco (FC-Zn. Avaliar alterações macro e micromorfológicas e a expressão de Fas promovidas pela TFD com FC-Zn tópica no modelo murino. MÉTODOS - Por meio da espectrometria de fluorescência, foram avaliadas combinações de diferentes períodos de oclusão tópica das formulações gel ou emulsão de FC-Zn (1mg/dl, com ou sem monoleína 5%, no dorso do camundongo hairless. Após oito horas das diferentes formulações, os camundongos foram expostos ao laser de diodo de 670nm, dose de 50J/cm-². RESULTADOS - A fluorescência foi discretamente superior após oito horas e com a emulsão nos intervalos de uma, duas e quatro horas de oclusão. A intensidade do edema e da erosão correspondeu à necrose da epiderme e à imunoexpressão de Fas nos cortes histológicos de pele. CONCLUSÕES - Os achados indicam a ação fotodinâmica promovida pela interação entre FC-Zn e fonte de luz de 670nm. As alterações macro e micromorfológicas foram correspondentes e mais substanciais com a emulsão FC-Zn e monoleína, sugerindo a acentuação dos efeitos com essa formulação. A imunoexpressão de Fas e as alterações histológicas sugeriram a apoptose como mecanismo de morte celular na TFD com FC-Zn tópica.BACKGROUND - Phthalocyanines are promising photosensitizers used in photodynamic therapy (PDT. OBJECTIVES - To evaluate the following parameters: intervals, vehicles and enhancer using topical zinc-phthalocyanine (Zn-PC formulation. To examine macro and micromorphological changes and Fas expression induced by topical Zn-PC-PDT on murine skin. MATERIAL AND METHODS - Using fluorescence spectrometry, different intervals of topical occlusion employing Zn-PC gel or emulsion, with or without monolein 5% were studied

  19. Development of human skin equivalents to unravel the impaired skin barrier in atopic dermatitis skin


    Eweje, M.O.


    The studies in this thesis describes the barrier defects in Atopic Dermatitis (AD) skin and various techniques to develop AD Human Skin Equivalents (HSEs) which can be used to better understand the role of several factors in the pathogenesis of AD skin. The results described show that Inflammation plays a pivotal role in the development of epidermal and SC features of AD skin and that AD epidermal features can be maintained in vitro when AD skin biopsies are used to generate explant-HSEs. The...

  20. Acoustic absorption by sunspots (United States)

    Braun, D. C.; Labonte, B. J.; Duvall, T. L., Jr.


    The paper presents the initial results of a series of observations designed to probe the nature of sunspots by detecting their influence on high-degree p-mode oscillations in the surrounding photosphere. The analysis decomposes the observed oscillations into radially propagating waves described by Hankel functions in a cylindrical coordinate system centered on the sunspot. From measurements of the differences in power between waves traveling outward and inward, it is demonstrated that sunspots appear to absorb as much as 50 percent of the incoming acoustic waves. It is found that for all three sunspots observed, the amount of absorption increases linearly with horizontal wavenumber. The effect is present in p-mode oscillations with wavelengths both significantly larger and smaller than the diameter of the sunspot umbrae. Actual absorption of acoustic energy of the magnitude observed may produce measurable decreases in the power and lifetimes of high-degree p-mode oscillations during periods of high solar activity.

  1. Chaotic systems with absorption

    CERN Document Server

    Altmann, Eduardo G; Tél, Tamás


    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate $\\kappa$ in terms of the natural conditionally-invariant measure of the system; (ii) an increased multifractality when compared to the spectrum of dimensions $D_q$ obtained without taking absorption and return times into account; and (iii) a generalization of the Kantz-Grassberger formula that expresses $D_1$ in terms of $\\kappa$, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results.

  2. Hydrogen Absorption by Niobium. (United States)


    incorporate an independent means for ascertaining surface cleanliness (e.g. AES). The form of the absorption curve in Fig. 7 appears to agree with that...very interesting study and is well within the capabilities of the systen designed, if the surface cleanliness can be assured. Wire specimens have a...assessing surface cleanliness would be an important supporting technique for understanding the results of these measurements. The simple kinetic

  3. Photoinduced absorption of polyalkylthienylenevinylenes

    Energy Technology Data Exchange (ETDEWEB)

    Botta, C. (Ist. di Chimica delle Macromolecole (CNR), Milano (Italy)); Bradley, D.D.C. (Cambridge Univ. (United Kingdom). Cavendish Lab.); Friend, R.H. (Cambridge Univ. (United Kingdom). Cavendish Lab.); Musco, A. (Ist. di Scienze Chimiche, Univ. di Urbino (Italy))


    We present a photoinduced absorption study of alkyl substituted poly(2,5-thienylenevinylene)s. Three photoinduced states are detected in both the solid state and in solution. The two low-energy bands are assigned to bipolarons, while a third band peaked near the band edge has a different origin. In solution photoexcitated states are very long-lived and we propose that photoexcitation recombine via a solvent-assisted photo-doping mechanism. (orig.)

  4. Infrared irradiation of skin for the development of non-invasive health monitoring technologies (United States)

    Abdussamad Abbas, Hisham; Triplett, Gregory


    Infrared radiation was employed to study the optical transmission properties of pigskin and the factors that influence transmission at room temperature. The skin samples from the forehead of piglets were irradiated using an infrared-pulsed source by varying the beam properties such as optical power, power density, duty cycle, as well as sample thickness. Because infrared radiation in select instances can penetrate through thick-fleshy skin more easily than visible radiation, temperature fluctuations observed within the skin samples stemming from exposure-dependent absorption revealed interesting transmission properties and the limits of optical exposure. Pigskin was selected for this study since its structure most closely resembles that of human skin. Furthermore, the pulsed beam technique compared to continuous operation offers more precise control of heat generation within the skin. Through this effort, the correlated pulsed-beam parameters that influence infrared transmission were identified and varied to minimize the internal absorption losses through the dermis layers. The two most significant parameters that reduce absorption losses were frequency and duty cycle of the pulsed beam. Using the Bouger-Beer-Lambert Law, the absorption coefficient from empirical data is approximated, while accepting that the absorption coefficient is neither uniform nor linear. Given that the optical source used in this study was single mode, the infrared spectra obtained from irradiated samples also reveal characteristics of the skin structure. Realization of appropriate sample conditions and exposure parameters that reduce light attenuation within the skin and sample degradation could give way to novel non-invasive measuring techniques for health monitoring purposes.

  5. Skin moisturization mechanisms: new data. (United States)

    Bonté, F


    The main function of the skin is to protect the body against exogenous substances and excessive water loss. The skin barrier is located in the outermost layer of the skin, called the stratum corneum, which is composed of corneocytes, originating from the keratinocytes differentiation process, embedded in organized complex lipid domains. Moisturizing of the skin is recognized as the first anti-aging skin care. Skin moisturization is essential for its appearance, protection, complexion, softness and the reinforcement of its barrier properties against deleterious and exogenous environmental factors. The intrinsic water binding capacity of skin is not only due to the complex natural moisturizing factor present in corneocytes, but also to hyaluronic acid and a regulated water transport within the skin. Recent data shows that the water movements between the cells at the different levels of the epidermis are due to dedicated water and glycerol transport proteins named aquaporins. Their role in the skin moisturization is completed by corneodesmosomes and tight junctions. Water and pH are now shown to be of prime importance in the regulation of the epidermal enzymes linked to corneocytes desquamation and lipid synthesis. Furthermore, the level of moisturization of the skin is important in its protection against repeated exposure to various irritant agents or phenomena such as very frequent washing with strong tensioactive materials.

  6. Influence of External Magnetic Field on Anomalous Skin Effects in Inductively Coupled Plasmas

    Institute of Scientific and Technical Information of China (English)

    MAO Ming; WANG You-Nian


    @@ Using a one-dimensional slab model, we study the influence of the external static magnetic field on the anomalous skin effects in the inductively coupled plasma. The rf electromagnetic field in the plasma is determined by solving the linearized Boltzmann equation incorporating with the Maxwell equations. The numerical results show that,due to the existence of the external magnetic field, the anomalous skin effects are greatly enhanced and the number of regions with negative absorption is decreased.

  7. Corrosion Problems in Absorption Chillers (United States)

    Stetson, Bruce


    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  8. Climate change and skin. (United States)

    Balato, N; Ayala, F; Megna, M; Balato, A; Patruno, C


    Global climate appears to be changing at an unprecedented rate. Climate change can be caused by several factors that include variations in solar radiation received by earth, oceanic processes (such as oceanic circulation), plate tectonics, and volcanic eruptions, as well as human-induced alterations of the natural world. Many human activities, such as the use of fossil fuel and the consequent accumulation of greenhouse gases in the atmosphere, land consumption, deforestation, industrial processes, as well as some agriculture practices are contributing to global climate change. Indeed, many authors have reported on the current trend towards global warming (average surface temperature has augmented by 0.6 °C over the past 100 years), decreased precipitation, atmospheric humidity changes, and global rise in extreme climatic events. The magnitude and cause of these changes and their impact on human activity have become important matters of debate worldwide, representing climate change as one of the greatest challenges of the modern age. Although many articles have been written based on observations and various predictive models of how climate change could affect social, economic and health systems, only few studies exist about the effects of this change on skin physiology and diseases. However, the skin is the most exposed organ to environment; therefore, cutaneous diseases are inclined to have a high sensitivity to climate. For example, global warming, deforestation and changes in precipitation have been linked to variations in the geographical distribution of vectors of some infectious diseases (leishmaniasis, lyme disease, etc) by changing their spread, whereas warm and humid environment can also encourage the colonization of the skin by bacteria and fungi. The present review focuses on the wide and complex relationship between climate change and dermatology, showing the numerous factors that are contributing to modify the incidence and the clinical pattern of many

  9. Epidemiology of skin cancer. (United States)

    Leiter, Ulrike; Eigentler, Thomas; Garbe, Claus


    Melanoma and nonmelanoma skin cancer (NMSC) are now the most common types of cancer in white populations. Both tumor entities show an increasing incidence rate worldwide but a stable or decreasing mortality rate. NMSC is the most common cancer in white-skinned individuals with a worldwide increasing incidence. NMSC is an increasing problem for health care services worldwide which causes significant morbidity. The rising incidence rates of NMSC are probably caused by a combination of increased exposure to ultraviolet (UV) or sun light, increased outdoor activities, changes in clothing style, increased longevity, ozone depletion, genetics and in some cases, immune suppression. An intensive UV exposure in childhood and adolescence was causative for the development of basal cell carcinoma (BCC) whereas for the etiology of SCC a chronic UV exposure in the earlier decades was accused. Cutaneous melanoma is the most rapidly increasing cancer in white populations, in the last 3 decades incidence rates have risen up to 5-fold. In 2008 melanoma was on place 5 in women and on place 8 in men of the most common solid tumor entities in Germany. The frequency of its occurrence is closely associated with the constitutive color of the skin, and the geographical zone. Changes in outdoor activities and exposure to sunlight during the past 50 years are an important factor for the increasing incidence of melanoma. Mortality rates of melanoma show a stabilization in the USA, Australia and also in European countries. In contrast to SCC, melanoma risk seems to be associated with an intermittent exposure to sunlight. Prevention campaigns aim on reducing incidence and achieving earlier diagnosis, which resulted in an ongoing trend toward thin melanoma since the last two decades. However, the impact of primary prevention measures on incidence rates of melanoma is unlikely to be seen in the near future, rather increasing incidence rates to 40-50/100,000 inhabitants/year should be expected in

  10. In vitro percutaneous absorption of ketoprofen and testosterone: comparison of pluronic lecithin organogel vs. pentravan cream. (United States)

    Lehman, Paul A; Raney, Sam G


    An in vitro human percutaneous absorption study was conducted to assess the delivery of ketoprofen and testosterone from two base formulations, a Pluronic lecithin organogel and Pentravan Cream. Each formulation was applied to ex vivo human trunk skin (from three skin donors) on triplicate sections mounted onto Franz Diffusion Cells. Following a 5-mcL/cm2 applied dose, serial dermal receptor solutions were collected over 48 hours. For both compounds, a greater rate and extent of absorption was found from the Pentravan formulation than from the Pluronic lecithin organogel formulation: 3.8-fold greater for ketoprofen, 1.7-fold greater for testosterone, for amount absorbed.

  11. Skin and bones. I. (United States)

    Orlow, S J; Watsky, K L; Bolognia, J L


    Skin disorders in which a radiograph may detect associated bony changes or abnormalities of calcification are discussed. They are grouped into eight categories: (1) inherited diseases (e.g., alkaptonuria, neurofibromatosis); (2) congenital disorders (e.g., Sturge-Weber and Proteus syndromes); (3) inflammatory conditions (e.g., dermatomyositis, sarcoidosis); (4) infections (e.g., dental sinus, syphilis); (5) neoplasias (e.g., histiocytosis, mastocytosis); (6) drug- and environment-induced (e.g., acroosteolysis, retinoid toxicity); (7) calcinosis cutis; and (8) osteoma cutis. Part I of our review discusses the first two categories.

  12. Skin and bones. II. (United States)

    Orlow, S J; Watsky, K L; Bolognia, J L


    Skin disorders in which a radiograph may detect associated bony changes or abnormalities of calcification are discussed. They are grouped into eight categories: (1) inherited diseases (e.g., alkaptonuria, neurofibromatosis); (2) congenital disorders (e.g., Sturge-Weber and Proteus syndromes); (3) inflammatory conditions (e.g., dermatomyositis, sarcoidosis); (4) infections (e.g., dental sinus, syphilis); (5) neoplasias (e.g., histiocytosis, mastocytosis); (6) drug- and environment-induced (e.g., acroosteolysis, retinoid toxicity); (7) calcinosis cutis; and (8) osteoma cutis. The first part of this review, published in the August 1991 issue of this JOURNAL, dealt with the first two categories; part II discusses categories 3 through 8.

  13. Shedding skin and tears. (United States)

    Hammlerschlag, Carl A


    I am a purported expert in change and personal growth; that's the work I do with patients, and what I lecture and write about. I say that growth has nothing to do with adding on; it's always about letting go. Alas, it's always easier to tell others how to welcome shedding their skins than it is for me to do it myself. Letting go of the old and familiar is a necessary prerequisite for growth, but it's hard to do because no matter how much we may know, we have to move on. It always makes us feel vulnerable, which can inspire fear.

  14. Is skin penetration a determining factor in skin sensitization ... (United States)

    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 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 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

  15. Converting Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho


    Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a sample and non-uniform intensity in the reverberation chambers under test. In this study, conversion methods from Sabine absorption...... coefficients to random incidence absorption coefficients are proposed. The overestimations of the Sabine absorption coefficient are investigated theoretically based on Miki's model for porous absorbers backed by a rigid wall or an air cavity, resulting in conversion factors. Additionally, three optimizations...

  16. Determination of human skin optical properties in vivo from reflectance spectroscopic measurements

    Institute of Scientific and Technical Information of China (English)

    Hongqin Yang; Shusen Xie; Hui Li; Zukang Lu


    A novel approach has been proved to quickly and non-invasively determine the optical properties of human skin in vivo. It is based on the diffuse reflectance approximation model and subjected to the well established library of absorption spectra of water and hemoglobin. Under the nonlinear least-square algorithm, fitting the measured spectra in the range of 400-1000 nm to the diffusion approximation model, the reduced scattering coefficient and absorption coefficient of skin tissue can be quickly determined in vivo. The results show that this method is convenient and suitable for the real-time clinical application.

  17. Acoustic Absorption Characteristics of People. (United States)

    Kingsbury, H. F.; Wallace, W. J.


    The acoustic absorption characteristics of informally dressed college students in typical classroom seating are shown to differ substantially from data for formally dressed audiences in upholstered seating. Absorption data, expressed as sabins per person or absorption coefficient per square foot, shows that there is considerable variation between…

  18. Annette Bunge: developing the principles in percutaneous absorption using chemical engineering principles. (United States)

    Stinchcomb, A L


    Annette Bunge and her research group have had the central theme of mathematically modeling the dermal absorption process. Most of the research focus has been on estimating dermal absorption for the purpose of risk assessment, for exposure scenarios in the environment and in the occupational setting. Her work is the basis for the United States Environmental Protection Agency's estimations for dermal absorption from contaminated water. It is also the basis of the dermal absorption estimates used in determining if chemicals should be assigned a 'skin notation' for potential systemic toxicity following occupational skin exposure. The work is truly translational in that it started with mathematical theory, is validated with preclinical and human experiments, and then is used in guidelines to protect human health. Her valued research has also extended into the topical drug bioavailability and bioequivalence assessment field.

  19. The 'beauty' of skin neurobiology. (United States)

    Pincelli, C; Bonté, F


    The skin is the most densely innervated organ in the body and there is a close relationship between the skin and the nervous system. Most skin cells express receptors for neuromediators (NM) and skin cells themselves are an important source of NM. In particular, human keratinocytes synthesize neurotrophins and endorphins and express their receptors. In addition to neurotrophic activity, NM are involved in skin homeostasis, trophism and stress responses. NM released from keratinocytes also function in a paracrine fashion on other skin cells, such as Langerhans cells, melanocytes and fibroblasts. We discuss the influence of NM on these cells, which may be involved in major cosmetic problems like ageing, baldness and dyspigmentation. Based on this correlation, it seems reasonable to target neural factors for cosmetic purposes.

  20. Pathophysiological Study of Sensitive Skin. (United States)

    Buhé, Virginie; Vié, Katell; Guéré, Christelle; Natalizio, Audrey; Lhéritier, Céline; Le Gall-Ianotto, Christelle; Huet, Flavien; Talagas, Matthieu; Lebonvallet, Nicolas; Marcorelles, Pascale; Carré, Jean-Luc; Misery, Laurent


    Sensitive skin is a clinical syndrome characterized by the occurrence of unpleasant sensations, such as pruritus, burning or pain, in response to various factors, including skincare products, water, cold, heat, or other physical and/or chemical factors. Although these symptoms suggest inflammation and the activation of peripheral innervation, the pathophysiogeny of sensitive skin remains unknown. We systematically analysed cutaneous biopsies from 50 healthy women with non-sensitive or sensitive skin and demonstrated that the intraepidermal nerve fibre density, especially that of peptidergic C-fibres, was lower in the sensitive skin group. These fibres are involved in pain, itching and temperature perception, and their degeneration may promote allodynia and similar symptoms. These results suggest that the pathophysiology of skin sensitivity resembles that of neuropathic pruritus within the context of small fibre neuropathy, and that environmental factors may alter skin innervation.

  1. Protecting the skin during thyroidectomy

    Directory of Open Access Journals (Sweden)

    Renan Bezerra Lira


    Full Text Available In this note we describe the standard technical maneuver used in our department to protect the skin during thyroidectomy in order to get the best aesthetic result. We use surgical gloves to protect the skin during these operations to reduce the negative impact of thermal trauma and mechanical retractors and energy delivery devices at the edges of the skin incised. This practice is effective, inexpensive, rapid, reproducible and showed no complication in our experience of over 2,500 thyroidectomies.

  2. Effect of ointment bases on topical and transdermal delivery of salicylic acid in rats: evaluation by skin microdialysis. (United States)

    Murakami, T; Yoshioka, M; Okamoto, I; Yumoto, R; Higashi, Y; Okahara, K; Yata, N


    Microdialysis has been used to determine the concentration of salicylic acid in skin tissue and plasma periodically for 4 h to evaluate the effect of ointment bases on topical and transdermal delivery of salicylic acid. The ointment bases examined were solbase (water-soluble), poloid and white petrolatum (oleaginous), hydrophilic poloid (water in oil (w/o) type emulsion lacking water) and absorptive ointment (w/o-type emulsion containing water). The ointments (0.1 g) containing 25 micromol salicylic acid were applied for 2 h to the surface of rat skin (1 cm2) with (intact) or without the stratum corneum. For intact skin, the extent of topical delivery from different ointments, evaluated by the area under the concentration-time curve (AUC) of salicylic acid in the skin tissue (AUCskin), increased in the order solbase salicylic acid in plasma (AUCplasma, transdermal delivery) varied remarkably among the different bases, the greatest ratio being observed for absorptive ointment. When the ointments were applied to skin surface without stratum corneum, AUCskin for solbase was much higher (about 45 times that for intact skin), whereas only a small (two-fold) increase was observed for poloid and hydrophilic poloid and the increase was negligible for white petrolatum and absorptive ointment. For skin without the stratum corneum, the ratio AUCskin/AUCplasma for the different ointments was comparable, although the magnitudes of AUCskin and AUCplasma still varied substantially. The variance of AUC values arises as a result of the different rates of release of salicylic acid from the bases. These results indicate that: the topical and transdermal delivery of salicylic acid in intact skin varies substantially among different ointment bases, and the greatest topical delivery is observed for absorptive ointment; use of absorptive ointment increases the retention of salicylic acid in the stratum corneum; and the stratum corneum functions strongly as a penetration barrier for

  3. Absorption heat pumps (United States)

    Huhtinen, M.; Heikkilae, M.; Andersson, R.


    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  4. Skin decontamination: principles and perspectives. (United States)

    Chan, Heidi P; Zhai, Hongbo; Hui, Xiaoying; Maibach, Howard I


    Skin decontamination is the primary intervention needed in chemical, biological and radiological exposures, involving immediate removal of the contaminant from the skin performed in the most efficient way. The most readily available decontamination system on a practical basis is washing with soap and water or water only. Timely use of flushing with copious amounts of water may physically remove the contaminant. However, this traditional method may not be completely effective, and contaminants left on the skin after traditional washing procedures can have toxic consequences. This article focuses on the principles and practices of skin decontamination.

  5. HOX genes in the skin

    Institute of Scientific and Technical Information of China (English)

    YANG Mei; LI Qing-feng; ZHANG Feng


    @@ Deep skin wounds heal by scar formation with a loss of its original appearance, structure and function.However, when the same damage occurs to the skin of an early gestational fetus, complete regeneration can be observed. Despite significant research in the field of skin regeneration, many mysteries remain, such as the loss of wound healing ability with maturity, the differences in healing at different parts of the body, and the presence of hypertrophic scars and keloids in some races but not in others. The finding of HOX genes in the skin provides new explanations to these conundrums.

  6. The future of skin metagenomics. (United States)

    Mathieu, Alban; Vogel, Timothy M; Simonet, Pascal


    Metagenomics, the direct exploitation of environmental microbial DNA, is complementary to traditional culture-based approaches for deciphering taxonomic and functional microbial diversity in a plethora of ecosystems, including those related to the human body such as the mouth, saliva, teeth, gut or skin. DNA extracted from human skin analyzed by sequencing the PCR-amplified rrs gene has already revealed the taxonomic diversity of microbial communities colonizing the human skin ("skin microbiome"). Each individual possesses his/her own skin microbial community structure, with marked taxonomic differences between different parts of the body and temporal evolution depending on physical and chemical conditions (sweat, washing etc.). However, technical limitations due to the low bacterial density at the surface of the human skin or contamination by human DNA still has inhibited extended use of the metagenomic approach for investigating the skin microbiome at a functional level. These difficulties have been overcome in part by the new generation of sequencing platforms that now provide sequences describing the genes and functions carried out by skin bacteria. These methodological advances should help us understand the mechanisms by which these microorganisms adapt to the specific chemical composition of each skin and thereby lead to a better understanding of bacteria/human host interdependence. This knowledge will pave the way for more systemic and individualized pharmaceutical and cosmetic applications.

  7. Infrared sensing based sensitive skin

    Institute of Scientific and Technical Information of China (English)

    CAO Zheng-cai; FU Yi-li; WANG Shu-guo; JIN Bao


    Developed robotics sensitive skin is a modularized, flexible, mini-type array of infrared sensors with data processing capabilities, which can be used to cover the body of a robot. Depending on the infrared sensors and periphery processing circuit, robotics sensitive skin can in real-time provide existence and distance information about obstacles for robots within sensory areas. The methodology of designing sensitive skin and the algorithm of a mass of IR data fusion are presented. The experimental results show that the multi-joint robot with this sensitive skin can work autonomously in an unknown environment.

  8. Absorption in dielectric models

    CERN Document Server

    Churchill, R J


    We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.

  9. Geospatial Absorption and Regional Effects

    Directory of Open Access Journals (Sweden)



    Full Text Available The geospatial absorptions are characterized by a specific complexity both in content and in their phenomenological and spatial manifestation fields. Such processes are differentiated according to their specificity to pre-absorption, absorption or post-absorption. The mechanisms that contribute to absorption are extremely numerous: aggregation, extension, diffusion, substitution, resistivity (resilience, stratification, borrowings, etc. Between these mechanisms frequent relations are established determining an amplification of the process and of its regional effects. The installation of the geographic osmosis phenomenon in a given territory (a place for example leads to a homogenization of the geospatial state and to the installation of the regional homogeneity.

  10. Sun protection factor persistence on human skin during a day without physical activity or ultraviolet exposure

    DEFF Research Database (Denmark)

    Beyer, Ditte Maria; Faurschou, Annesofie; Philipsen, Peter Alshede


    Recently, we showed that the sun protection factor (SPF) decreases by a constant factor to reach 55% during a day with activities. Organic sunscreens but not inorganic ones are absorbed through the skin. We wished to determine the SPF decrease caused by absorption by investigating the difference...... in SPF decreases between an organic and an inorganic sunscreen, assuming that the sunscreens are stable, and that the SPF decrease is time dependent if caused by absorption....

  11. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas


    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  12. Trophic skin ulceration of leprosy: skin and serum zinc concentrations. (United States)

    Oon, B B; Khong, K Y; Greaves, M W; Plummer, V M


    Skin and serum zinc measurements have been made in patients with leprosy with and without trophic skin ulceration and in several other groups. Serum zinc concentrations were decreased in leprosy irrespective of the presence or absence of skin ulceration. Serum zinc concentrations in leprosy were also unrelated to smears positive for Mycobacterium leprae and to the clinical type of leprosy. Since a decrease of the serum zinc was also found in patients with dermatitis herpetiformis and pulmonary tuberculosis it seems likely that the decreased serum zinc in leprosy is a nonspecific metabolic consequence of chronic skin and internal disease. The mean skin zinc concentration in leprosy did not differ significantly from the corresponding value in control subjects, the lack of agreement between serum and skin concentrations being possibly related to the presence of nonexchangeable keratin-bound zinc in skin. Though the clinical significance of lowered serum zinc concentrations in leprosy is uncertain therapeutic trials of zinc treatment in leprosy with trophic skin ulceration seem justifiable.

  13. Hospital celebrates skin to skin contact to raise awareness. (United States)


    NEONATAL nurses at Birmingham's City Hospital have been celebrating the benefits of skin to skin contact with premature babies. They held a week of celebrations in the unit last month, in which they promoted the kangaroo care technique and breastfeeding to parents.

  14. Species-specific cutaneous biotransformation of the pesticide propoxur during percutaneous absorption in vitro. (United States)

    van de Sandt, J J; Rutten, A A; van Ommen, B


    Propoxur (2-isopropoxyphenyl N-methylcarbamate) is a pesticide with a wide spectrum of applications, including use in agriculture and greenhouses. Percutaneous absorption and concurrent cutaneous metabolism of propoxur were studied in a two-compartment organ culture model. Nontoxic concentrations of [14C]propoxur were applied topically to skin discs from human, rabbit, and porcine origin. Permeation rates were comparable in human and rabbit skin, while pig skin was found to be twice as permeable. Furthermore, it was demonstrated that skin tissue of all three species had the capacity to metabolize propoxur. Hydrolysis of propoxur yielded 2-isopropoxyphenol (IPP), followed by phase II conjugation reactions. Interestingly, the type of IPP conjugation appeared to be species specific. In porcine skin cultures, glucuronides and sulfates were detected in equal amounts, whereas in human skin only sulfate conjugation was observed. For rabbit skin, glucuronidation was the major route of conjugation, with minor amounts of the sulfate conjugate and an unidentified metabolite. The percentage of propoxur metabolism in rabbit skin was not influenced by the dose in the range of 25-200 micrograms/cm2; in contrast, human skin metabolism was virtually saturated at 100 micrograms/cm2.

  15. The HI absorption 'Zoo'

    CERN Document Server

    Gereb, K; Morganti, R; Oosterloo, T A


    We present an analysis of the HI absorption in a sample of 101 flux-selected radio AGN (S_1.4 GHz > 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). HI absorption is detected in 32 galaxies, showing a broad variety of widths, shapes and kinematical properties. We characterize the HI spectra of the individual detections using the busy function (Westmeier et al. 2014). With the goal of identifying different morphological structures of HI, we study the kinematical and radio source properties of the detections as function of their width. Narrow lines (FWHM = 500 km/s). These detections are good candidates for being HI outflows. The detection rate of HI outflows is 5 percent in the total radio AGN sample. This fraction represents a lower limit, however it could suggests that, if outflows are a characteristic phenomenon of all radio sources, they would have a short depletion timescale compared to the lifetime of the AGN. Blueshifted and broad/asymmetric lines are more often present among young...

  16. Optical coherence tomography for imaging of skin and skin diseases

    DEFF Research Database (Denmark)

    Mogensen, Mette; Thrane, Lars; Jørgensen, Thomas Martini


    Optical coherence tomography (OCT) is an emerging imaging technology based on light reflection. It provides real-time images with up to 2-mm penetration into the skin and a resolution of approximately 10 μm. It is routinely used in ophthalmology. The normal skin and its appendages have been studied......, as have many diseases. The method can provide accurate measures of epidermal and nail changes in normal tissue. Skin cancer and other tumors, as well as inflammatory diseases, have been studied and good agreement found between OCT images and histopathological architecture. OCT also allows noninvasive...... monitoring of morphologic changes in skin diseases and may have a particular role in the monitoring of medical treatment of nonmelanoma skin cancer. The technology is however still evolving and continued technological development will necessitate an ongoing evaluation of its diagnostic accuracy. Several...

  17. How to Choose the Best Skin Care Products (United States)

    ... Lines and Forehead Furrows Hair Loss Hyperpigmentation Melasma Sagging Skin Scars Skin Growths Skin Lesions Spider Veins ... Lines and Forehead Furrows Hair Loss Hyperpigmentation Melasma Sagging Skin Scars Skin Growths Skin Lesions Spider Veins ...

  18. Pygmies, Giants, and Skins

    CERN Document Server

    Piekarewicz, J


    Understanding the equation of state (EOS) of neutron-rich matter is a central goal of nuclear physics that cuts across a variety of disciplines. Indeed, the limits of nuclear existence, the collision of energetic heavy ions, the structure of neutron stars, and the dynamics of core-collapse supernova all depend critically on the nuclear-matter EOS. In this contribution I focus on the EOS of cold baryonic matter with special emphasis on its impact on the structure, dynamics, and composition of neutron stars. In particular, I discuss how laboratory experiments on neutron skins as well as on Pygmy and Giant resonances can help us elucidate the structure of these fascinating objects.

  19. Spaceship with heat-isolating outer skin

    NARCIS (Netherlands)

    Van Baten, T.J.; Buursink, J.


    A spaceship provided with a skin layer and cooling member for the skin layer that comprises a liquid-holding layer provided behind the skin layer, with an empty space being present between the liquid holding layer and the skin layer, so as to prevent heat transfer due to conduction between the skin

  20. Measurement of the optical properties of skin using terahertz time-domain spectroscopic techniques (United States)

    Wilmink, Gerald J.; Ibey, Bennett L.; Tongue, Thomas; Schulkin, Brian; Peralta, Xomalin; Rivest, Benjamin D.; Haywood, Eric C.; Roach, William P.


    Terahertz (THz) radiation is increasingly being used in biomedical imaging and spectroscopy applications. These techniques show tremendous promise to provide new sophisticated tools for the improved detection of skin cancer. However, despite recent efforts to develop these applications, few studies have been conducted to characterize the optical properties of skin at THz frequencies. Such information is required to better understand THz-tissue interactions, and is critical for determining the feasibility of proposed applications. In this study, we have developed and tested a THz time-domain spectroscopy system. We used this system to acquire the optical properties for fresh and frozen/thawed excised porcine skin from 0.1 to 2.0 THz. Results show that the index of refraction (n) for both frozen and fresh skin decreases with frequency. For frozen skin, n equals 2.5 at 0.1 THz and 2.0 at 2.0 THz, and for fresh skin equals 2.0 at 0.1 THz and 1.7 at 2.0 THz. Values for the absorption coefficient (μa) increase with frequency for both frozen and fresh skin. Frozen skin exhibits μa values equal to 56 cm-1 at 0.1 THz and 550 cm-1 at 2.0 THz, whereas fresh skin exhibits values of 56 cm-1 at 0.1 THz and 300 cm-1 at 2.0 THz. Assuming the optical penetration depth (δ) is inversely proportional to μa (absorption-dominated interactions), THz radiation has limited δ in skin (200 μm at 0.1 THz to 40 μm at 2.0 THz). These results suggest that applications exploiting THz radiation show the most promise for investigating superficial tissues.

  1. Pain-induced skin autoimmunity


    Odoardi, Francesca; Neuhuber, Winfried; Flügel, Alexander


    A recent paper published in Nature reports sensory nerve fibers in the skin that give local immune cells important instructions for the organization of an immune response; in this particular case the cooperation between the nervous and immune systems had disastrous consequences, namely an auto-destruction of the skin.

  2. Hereditary skin diseases of hemidesmosomes

    NARCIS (Netherlands)

    Jonkman, MF


    Studies of hereditary blistering skin diseases (epidermolysis bullosa) and targeted gene mutation experiments in knockout mice have greatly improved our understanding of hemidesmosomes and their associated structures in the cytoskeleton and basement membrane of the skin and mucous membranes. At leas

  3. Co-drug strategy for promoting skin targeting and minimizing the transdermal diffusion of hydroquinone and tranexamic acid. (United States)

    Hsieh, Pei-Wen; Chen, Wei-Yu; Aljuffali, Ibrahim A; Chen, Chun-Che; Fang, Jia-You


    Hydroquinone and tranexamic acids (TXA) are skin-lightening agents with a hydrophilic nature and low skin absorption. A high dose is needed for clinical use, resulting in a high incidence of skin irritation. Co-drugs formed by conjugating hydroquinone and TXA were synthesized and their in vitro and in vivo skin absorption characteristics were evaluated. The two synthesized co-drugs were 4-hydroxyphenyl 4-(aminomethyl)cyclohexanecarboxylate (HAC) and 1,4- phenylene bis(aminomethyl)cyclohexanecarboxylate (BAC). The co-drugs were chemically stable in aqueous solution, but rapidly degraded to the respective parent drug in esterases and skin homogenates. Compared to hydroquinone application, 7.2- and 2.4-fold increments in the hydroquinone skin deposition were obtained with the in vitro application of HAC and BAC. HAC and BAC led to 3- and 2-fold enhancements of equivalent TXA deposition compared to TXA administration. The in vivo experiment showed a further enhancement of co-drugs compared to the in vitro setup. The transdermal penetration of co-drugs, especially BAC, was much lower than that of hydroquinone and TXA. This indicated high-level skin targeting by the co-drugs. HAC and BAC revealed strong affinities for the viable epidermis/dermis. Hair follicles are important reservoirs for co-drug delivery. Daily administration of co-drugs to the skin did not generate irritation for up to 7 days. Both co-drugs are superior candidates for treating skin hyperpigmentation.

  4. Interactions between novel terpenes and main components of rat and human skin: mechanistic view for transdermal delivery of propranolol hydrochloride. (United States)

    Ahad, Abdul; Aqil, Mohammed; Kohli, Kanchan; Sultana, Yasmin; Mujeeb, Mohd; Ali, Asgar


    The purpose of this study was to investigate the effectiveness and mechanism(s) of percutaneous absorption of propranolol hydrochloride (PHCL) across rat and human cadaver skin using seven novel terpenes with reference to marker terpene 1,8-cineole. In-vitro skin permeation studies were carried out via rat and human skin models. The mechanism of skin permeation of PHCL by terpenes was evaluated by FTIR, DSC, activation energy measurement and histopathological examination. Amongst the new terpenes, 1,4-cineole was found to be most effective enhancer for diffusion of PHCL through rat skin (ER=3.07) and human cadaver skin (ER=2.42) as compared to control. FTIR spectra and DSC thermogram of skin treated with aforesaid terpenes indicated that permeation occurred due to the disruption of lipid bilayers. No apparent skin irritation (erythema, edema) was observed on treatment of skin with terpenes, the irritation was higher with the β-citronellene and rose oxide. It was concluded that 1,4-cineole can be successfully used as potential permeation enhancer for PHCL. It enhanced the absorption of hydrophilic drug by extraction and disruption of lipid bilayers and keratin denaturation of stratum corneum.

  5. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho


    Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a specimen and non-uniform intensity in the test chamber. In this study, several methods that convert Sabine absorption coefficients...... into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods...

  6. The HI absorption "Zoo" (United States)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.


    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis on the radio sources, while here we characterize the absorption spectra of the individual detections using the recently presented busy function. The H I absorption spectra show a broad variety of widths, shapes, and kinematical properties. The full width half maximum (FWHM) of the busy function fits of the detected H I lines lies in the range 32 km s-1 200 km s-1). We study the kinematical and radio source properties of each group, with the goal of identifying different morphological structures of H I. Narrow lines mostly lie at the systemic velocity and are likely produced by regularly rotating H I disks or gas clouds. More H I disks can be present among galaxies with lines of intermediate widths; however, the H I in these sources is more unsettled. We study the asymmetry parameter and blueshift/redshift distribution of the lines as a function of their width. We find a trend for which narrow profiles are also symmetric, while broad lines are the most asymmetric. Among the broadest lines, more lines appear blueshifted than redshifted, similarly to what was found by previous studies. Interestingly, symmetric broad lines are absent from the sample. We argue that if a profile is broad, it is also asymmetric and shifted relative to the systemic velocity because it is tracing unsettled H I gas. In particular, besides three of the broadest (up to FW20 = 825 km s-1) detections, which are associated with gas-rich mergers, we find three new cases of profiles with blueshifted broad wings (with FW20 ≳ 500 km s-1) in high radio power AGN. These detections are good candidates for being HI outflows. Together with the known cases of outflows already included in the sample (3C 293 and

  7. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)

    XIANG FuYuan; LIANG ShunLin; LI AiGen


    The diffuse interstellar bands (DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s, the exact nature of DIBs still remains unclear. This article reviews the history of the detec-tions of DIBs in the Milky Way and external galaxies, the major observational characteristics of DIBs, the correlations or anti-correlations among DIBs or between DIBs and other interstellar features (e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise), and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  8. Diffuse interstellar absorption bands

    Institute of Scientific and Technical Information of China (English)


    The diffuse interstellar bands(DIBs) are a large number of absorption bands that are superposed on the interstellar extinction curve and are of interstellar origin. Since the discovery of the first two DIBs in the 1920s,the exact nature of DIBs still remains unclear. This article reviews the history of the detections of DIBs in the Milky Way and external galaxies,the major observational characteristics of DIBs,the correlations or anti-correlations among DIBs or between DIBs and other interstellar features(e.g. the prominent 2175 Angstrom extinction bump and the far-ultraviolet extinction rise),and the proposed candidate carriers. Whether they are also present in circumstellar environments is also discussed.

  9. Dosimetry for Total Skin Electron Beam Therapy in Skin Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Sung Sil; Loh, John J. K.; Kim, Gwi Eon [Yonsei University College of Medicine, Seoul (Korea, Republic of)


    Increasing frequency of skin cancer, mycosis fungoides, Kaposi sarcoma etc, it need to treatment dose planning for total skin electron beam (TSEB) therapy. Appropriate treatment planning for TSEB therapy is needed to give homogeneous dose distribution throughout the entire skin surface. The energy of 6 MeV electron from the 18 MeV medical linear accelerator was adapted for superficial total skin electron beam therapy. The energy of the electron beam was reduced to 4.2 MeV by a 0.5cmx90cmx180cm acryl screen placed in a feet front of the patient. Six dual field beam was adapted for total skin irradiation to encompass the entire body surface from head to toe simultaneously. The patients were treated behind the acryl screen plate acted as a beam scatterer and contained a parallel-plate shallow ion chamber for dosimetry and beam monitoring. During treatment, the patient was placed in six different positions due to be homogeneous dose distribution for whole skin around the body. One treatment session delivered 400 cGy to the entire skin surface and patients were treated twice a week for eight consecutive weeks, which is equivalent to TDF value 57. Instrumentation and techniques developed in determining the depth dose, dose distribution and bremsstrahlung dose are discussed.

  10. Skin protection in the prevention of skin diseases. (United States)

    Elsner, Peter


    Occupational skin diseases comprise a wide spectrum of conditions. Under epidemiological aspects, occupational contact dermatitis that is usually manifested on the hands is the most frequent occupational skin disease with an estimated average incidence rate of 0.7-1.5 cases per 1,000 workers per year. Irritant dermatitis is due to individual susceptibility and the exposure to irritants such as wet work combined with detergents or other hydrophilic irritants or solvents at the workplace. Chronic irritant dermatitis is a risk factor for delayed-type sensitization and subsequently allergic contact dermatitis. It is therefore the prevention of chronic or cumulative irritant dermatitis that is the decisive factor in the prevention of occupational skin disease. Within prevention programs at the workplace, skin protection plays an important, but limited role. Others are technical and organizational means to avoid or reduce skin exposure to irritants and allergens. Educational measures to increase the awareness of workers for workplace hazards and to motivate them to use skin protection measures appropriately are just as important as the careful selection of skin protection materials.

  11. Periostin in Skin Tissue Skin-Related Diseases

    Directory of Open Access Journals (Sweden)

    Yukie Yamaguchi


    Recently, periostin—a matricellular protein—has been highlighted for its pivotal functions in the skin. Analysis of periostin null mice has revealed that periostin contributes to collagen fibrillogenesis, collagen cross-linking, and the formation of ECM meshwork via interactions with other ECM components. Periostin expression is enhanced by mechanical stress or skin injury; this is indicative of the physiologically protective functions of periostin, which promotes wound repair by acting on keratinocytes and fibroblasts. Along with its physiological functions, periostin plays pathogenic roles in skin fibrosis and chronic allergic inflammation. In systemic sclerosis (SSc patients, periostin levels reflect the severity of skin fibrosis. Periostin null mice have shown reduced skin fibrosis in a bleomycin-induced SSc mouse model, indicating a key role of periostin in fibrosis. Moreover, in atopic dermatitis (AD, attenuated AD phenotype has been observed in periostin null mice in a house dust mite extract-induced AD mouse model. Th2 cytokine-induced periostin acts on keratinocytes to produce inflammatory cytokines that further enhance the Th2 response, thereby sustaining and amplifying chronic allergic inflammation. Thus, periostin is deeply involved in the pathogenesis of AD and other inflammation-related disorders affecting the skin. Understanding the dynamic actions of periostin would be key to dissecting pathogenesis of skin-related diseases and to developing novel therapeutic strategies.

  12. Dermal absorption of a dilute aqueous solution of malathion

    Directory of Open Access Journals (Sweden)

    Scharf John


    Full Text Available Malathion is an organophosphate pesticide commonly used on field crops, fruit trees, livestock, agriculture, and for mosquito and medfly control. Aerial applications can result in solubilized malathion in swimming pools and other recreational waters that may come into contact with human skin. To evaluate the human skin absorption of malathion for the assessment of risk associated with human exposures to aqueous solutions, human volunteers were selected and exposed to aqueous solutions of malathion. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred state. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human exposure for various periods of time. No measurable skin absorption was detected in 42% of the participants; the remaining 58% of participants measured minimal absorbed doses of malathion. Analyzing these results through the Hazard Index model for recreational swimmer and bather exposure levels typically measured in contaminated swimming pools and surface waters after bait application indicated that these exposures are an order of magnitude less than a minimal dose known to result in a measurable change in acetylcholinesterase activity. It is concluded that exposure to aqueous malathion in recreational waters following aerial bait applications is not appreciably absorbed, does not result in an effective dose, and therefore is not a public health hazard.

  13. Noninvasive evaluation of collagen and hemoglobin contents and scattering property of in vivo keloid scars and normal skin using diffuse reflectance spectroscopy: pilot study (United States)

    Tseng, Sheng-Hao; Hsu, Chao-Kai; Yu-Yun Lee, Julia; Tzeng, Shih-Yu; Chen, Wan-Rung; Liaw, Yu-Kai


    Collagen is a rich component in skin that provides skin structure integrity; however, its contribution to the absorption and scattering properties of various types of skin has not been extensively studied. We considered the contribution of the collagen to the absorption spectrum of in vivo normal skin and keloids of 12 subjects derived from our diffuse reflectance spectroscopy (DRS) system in the wavelength range from 550 to 860 nm. It was found that the collagen concentration, the hemoglobin oxygen saturation, and the reduced scattering coefficient of keloids were remarkably different from that of normal skin. Our results suggest that our DRS system could assist clinicians in understanding the functional and structural condition of keloid scars. In the future, we will evaluate the accuracy of our system in the keloid diagnosis and investigate the applicability of our system for other skin-collagen-related studies.

  14. Skin Exposures & Effects in the Workplace (United States)

    ... Topics Publications and Products Programs Contact NIOSH NIOSH SKIN EXPOSURES & EFFECTS Recommend on Facebook Tweet Share Compartir ... currently lacking for measuring and assessing skin exposures. Skin Notation (SK) Profiles NIOSH has developed a strategy ...

  15. Absorption intestinale des vitamines liposolubles


    Reboul Emmanuelle


    The molecular mechanisms of fat-soluble vitamin intestinal absorption remain partly unknown, despite the fact that a better understanding of this process would certainly allow to improve their bioavailability. If their digestion-absorption process follows the fate of lipids globally, the recent discovery of membranes proteins involved in their absorption questioned the established dogmas. These new data should be taken into account to avoid dietary or drug interactions that may limit some fat...

  16. Absorption intestinale des vitamines liposolubles

    Directory of Open Access Journals (Sweden)

    Reboul Emmanuelle


    Full Text Available The molecular mechanisms of fat-soluble vitamin intestinal absorption remain partly unknown, despite the fact that a better understanding of this process would certainly allow to improve their bioavailability. If their digestion-absorption process follows the fate of lipids globally, the recent discovery of membranes proteins involved in their absorption questioned the established dogmas. These new data should be taken into account to avoid dietary or drug interactions that may limit some fatsoluble vitamin bioavailability.

  17. Analytical model of diffuse reflectance spectrum of skin tissue

    Energy Technology Data Exchange (ETDEWEB)

    Lisenko, S A; Kugeiko, M M; Firago, V A [Belarusian State University, Minsk (Belarus); Sobchuk, A N [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk (Belarus)


    We have derived simple analytical expressions that enable highly accurate calculation of diffusely reflected light signals of skin in the spectral range from 450 to 800 nm at a distance from the region of delivery of exciting radiation. The expressions, taking into account the dependence of the detected signals on the refractive index, transport scattering coefficient, absorption coefficient and anisotropy factor of the medium, have been obtained in the approximation of a two-layer medium model (epidermis and dermis) for the same parameters of light scattering but different absorption coefficients of layers. Numerical experiments on the retrieval of the skin biophysical parameters from the diffuse reflectance spectra simulated by the Monte Carlo method show that commercially available fibre-optic spectrophotometers with a fixed distance between the radiation source and detector can reliably determine the concentration of bilirubin, oxy- and deoxyhaemoglobin in the dermis tissues and the tissue structure parameter characterising the size of its effective scatterers. We present the examples of quantitative analysis of the experimental data, confirming the correctness of estimates of biophysical parameters of skin using the obtained analytical expressions. (biophotonics)

  18. Use of optical skin phantoms for calibration of dermatological lasers (United States)

    Wróbel, M. S.; Sekowska, A.; Marchwiński, M.; Galla, S.; Cenian, A.


    A wide range of dermatological diseases can be efficiently treated using laser heating. Nevertheless, before the new laser is introduced into clinical practice, its parameters and ability to interact with human skin have to be carefully examined. In order to do that optical skin phantoms can be used. Such phantoms closely imitate the scattering and absorption properties of real human skin tissue along with its thermal properties, such as capacitance and conductivity specific heat. We have fabricated a range of optical tissue phantoms based on polyvinylchloride-plastisol PVC-P with varying optical properties, including the absorption, scattering and density of the matrix material. We have utilized a pre-clinical dermatological laser system with a 975 nm diode laser module. A range of laser settings were tested, such as laser pulse duration, laser power and number of pulses. We have studied laser irradiation efficiency on fabricated optical tissue phantoms. Measurements of the temporal and spatial temperature distribution on the phantoms' surface were performed using thermographic imaging. The comparison of results between tissues' and phantoms' optical and thermal response prove that they can be used for approximate evaluation of laser heating efficiency. This study presents a viable approach for calibration of dermatological lasers which can be utilized in practice.

  19. Analytical model of diffuse reflectance spectrum of skin tissue (United States)

    Lisenko, S. A.; Kugeiko, M. M.; Firago, V. A.; Sobchuk, A. N.


    We have derived simple analytical expressions that enable highly accurate calculation of diffusely reflected light signals of skin in the spectral range from 450 to 800 nm at a distance from the region of delivery of exciting radiation. The expressions, taking into account the dependence of the detected signals on the refractive index, transport scattering coefficient, absorption coefficient and anisotropy factor of the medium, have been obtained in the approximation of a two-layer medium model (epidermis and dermis) for the same parameters of light scattering but different absorption coefficients of layers. Numerical experiments on the retrieval of the skin biophysical parameters from the diffuse reflectance spectra simulated by the Monte Carlo method show that commercially available fibre-optic spectrophotometers with a fixed distance between the radiation source and detector can reliably determine the concentration of bilirubin, oxy- and deoxyhaemoglobin in the dermis tissues and the tissue structure parameter characterising the size of its effective scatterers. We present the examples of quantitative analysis of the experimental data, confirming the correctness of estimates of biophysical parameters of skin using the obtained analytical expressions.

  20. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.


    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  1. Two-photon absorption and transient photothermal imaging of pigments in tissues (United States)

    Ye, Tong; Fu, Dan; Matthews, Thomas E.; Hong, Lian; Simon, John D.; Warren, Warren S.


    As a main pigment in skin tissues, melanin plays an important role in photo-protecting skin from UV radiation. However, melanogenesis may be altered due to disease or environmental factors; for example, sun exposure may cause damage and mutation of melanocytes and induce melanoma. Imaging pigmentation changes may provide invaluable information to catch the malignant transformation in its early stage and in turn improve the prognosis of patients. We have demonstrated previously that transmission mode, two-photon, one- or two-color absorption microscopy could provide remarkable contrast in imaging melanin in skin. In this report we demonstrate significantly improved sensitivity, so that we are now able to image in epi-mode (or back reflection) in two-photon absorption. This improvement makes possible for us to characterize the different types of pigmentation on the skin in vivo at virtually any location. Another finding is that we can also image transient photothermal dynamics due to the light absorption of melanin. By carefully choosing excitation and probe wavelengths, we might be able to image melanin in different structures under different micro-environments in skin, which could provide useful photochemical and photophysical insights in understanding how pigments are involved in photoprotection and photodamage of cells.

  2. DNA adducts in skin biopsies and 1-hydroxypyrene in urine of psoriasis patients and healthy volunteers following treatment with coal tar.

    NARCIS (Netherlands)

    Hendricksen-Roelofzen, J.H.J.; Valk, P.G.M. van der; Godschalk, R.; Dettbarn, G.; Seidel, A.; Golsteijn, L.; Anzion, R.B.; Aben, K.K.H.; Schooten, F.J.L. van; Kiemeney, L.A.L.M.; Scheepers, P.T.J.


    Coal tar ointments (CTO) are frequently used in the treatment of psoriasis and eczema, but CTO contain carcinogenic polycyclic aromatic hydrocarbons (PAH). PAH are absorbed and metabolized in the skin. In psoriasis, the skin barrier is altered and therefore, absorption and metabolism of PAH may diff

  3. Age-related skin changes

    Directory of Open Access Journals (Sweden)

    Božanić Snežana


    Full Text Available Age-related skin changes can be induced by chronological ageing, manifested in subcutaneous fat reduction, and photo-ageing eliciting increased elastotic substance in the upper dermis, destruction of its fibrilar structure, augmented intercellular substance and moderate inflammatory infiltrate. Forty-five biopsy skin samples of the sun-exposed and sun-protected skin were analyzed. The patients were both males and females, aged from 17 to 81 years. The thickness of the epidermal layers and the number of cellular living layers is greater in younger skin. The amount of keratohyaline granules is enlarged in older skin. Dermoepidermal junction is flattened and the presence of elastotic material in the dermis is pronounced with age. The amount of inflammatory infiltrate is increased, the fibrous trabeculae are thickened in older skin and the atrophy of the hypodermis is observed. Chronological ageing alters the fibroblasts metabolism by reducing their life span, capacity to divide and produce collagen. During ageing, the enlargement of collagen fibrils diminishes the skin elasticity.

  4. Biothermomechanical behavior of skin tissue

    Institute of Scientific and Technical Information of China (English)

    F.Xu; T.J.Lu; K.A.Seffen


    Advances in laser,microwave and similar tech nologies have led to recent developments of thermal treatments involving skin tissue.The effectiveness of these treatments is governed by the coupled thermal,mechanical,biological and neural responses of the affected tissue:a favorable interaction results in a procedure with relatively little pain and no lasting side effects.Currently,even though each behavioral facet is to a certain extent established and understood,none exists to date in the interdisciplinarv area.A highly interdisciplinary approach is required for studying the biothermomechanical behavior of skin,involving bioheat transfer.biomechanics and physiology.A comprehensive literature review penrtinent to the subject is presented in this paper,covering four subject areas:(a)skin structure,(b)skin bioheat transfer and thermal damage,(c)skin biomechanics,and(d)skin biothermomechanics.The major problems,issues,and topics for further studies are also outlined.This review finds that significant advances in each of these aspects have been achieved in recent years.Although focus is placed upon the biothermomechanical behavior of skin tissue,the fundamental concepts and methodologies reviewed in this paper may also be applicable for studying other soft tissues.

  5. Human skin volatiles: a review. (United States)

    Dormont, Laurent; Bessière, Jean-Marie; Cohuet, Anna


    Odors emitted by human skin are of great interest to biologists in many fields; applications range from forensic studies to diagnostic tools, the design of perfumes and deodorants, and the ecology of blood-sucking insect vectors of human disease. Numerous studies have investigated the chemical composition of skin odors, and various sampling methods have been used for this purpose. The literature shows that the chemical profile of skin volatiles varies greatly among studies, and the use of different sampling procedures is probably responsible for some of these variations. To our knowledge, this is the first review focused on human skin volatile compounds. We detail the different sampling techniques, each with its own set of advantages and disadvantages, which have been used for the collection of skin odors from different parts of the human body. We present the main skin volatile compounds found in these studies, with particular emphasis on the most frequently studied body regions, axillae, hands, and feet. We propose future directions for promising experimental studies on odors from human skin, particularly in relation to the chemical ecology of blood-sucking insects.

  6. Sun protection factor persistence on human skin during a day without physical activity or ultraviolet exposure

    DEFF Research Database (Denmark)

    Beyer, Ditte Maria; Faurschou, Annesofie; Philipsen, Peter Alshede


    Recently, we showed that the sun protection factor (SPF) decreases by a constant factor to reach 55% during a day with activities. Organic sunscreens but not inorganic ones are absorbed through the skin. We wished to determine the SPF decrease caused by absorption by investigating the difference...

  7. Provesicular Niosomes Gel: A Novel Absorption Modulator for Transdermal Delivery

    Directory of Open Access Journals (Sweden)



    Full Text Available Skin has become an impressive and idealistic platform for the delivery of drugs compared to other routes. However, the stratum corneum “dead, impermeable barrier devoid of biological activity” to skin had challenged the development of transdermal product, which delivers the drugs directly to the systemic circulation at a controlled rate[1]. Several approaches put forward to enhance the penetration of drug through skin for transdermal drug delivery and one among them are provesicular niosomes (proniosomes, which ideally possess the sole property of reversibly reducing the barrier resistance of the horny layer, allowing the drug to reach the living tissues at a greater rate. The provesicular niosomes (non-ionic surfactant based vesicles; colloid carrier is still in its infancy and need to exploit more in field of drug delivery. These vesicles are formed from the self-assembly of non-ionic amphiphiles in aqueous medium results in closed bilayer structure which can entraps both lipophilic and hydrophilic drugs[2]. They are non-toxic and non-immunogenic bilayer that be converted to niosomes when applied to skin by in-situ absorption of water and interacts with the strong hydrogen bond of stratum corneum and loosens it, thereby allowing the diffusion of drug into the skin. It also possesses enhanced stability compared to other vesicular carrier. This review is an insight into the exploitation of the various properties of drug to encapsulated, preparation, mechanism of penetration and application in transdermal drug delivery. The factor affecting the entrapment and penetration of drug through the skin also reviewed.

  8. Chemokines in the skin

    Directory of Open Access Journals (Sweden)

    Prasad D


    Full Text Available In last few years, focus has shifted from cytokines which have pleiotropic biologic properties to chemokines with target cell selective activity. The separation has led frequently espoused proposition that chemokines are involved in the pathogenesis of disease having specific infiltrates and point to possible role in Chronic skin diseases. Depending upon the structure these chemokines are divided into three subfamilies, two major subfamilies: CXC and CC, and one putative subfamily C with only one member known as lymphotactin. A recent insight into chemokine physiology comes from demonstration of interaction between chemokines and their cloned receptors. These chemokine receptors are members of the transmembrane spanning (7-TMS, G-protein- coupled receptor family. So far CXC chemokine receptors and seven CC receptors have been cloned. Recently, the importance of selective chemoattractant activity of chemokines has been overshadowed by chemokine receptors emerging as new targets for anti-HIV therapy as the connection between chemokines and HIV-I had been established. Among the CXC chemokine receptors, CXCR4, and among the CC chemokines receptors, CCRI, CCR2b, CCR3, and CCR5 have been implicated as HIV-1 coreceptors.

  9. Development of prosthetic skin (United States)

    Kilaru, Rohit

    The objective of this research was to embed tactile sensors in polyimides. This novel method could be utilized to realize prosthetic skin for sensing different kinds of mechanical stimuli. Tactile sensors have an increasing demand in medical sectors: upper and lower-limb prosthetics and in the industrial sectors: robot end-effectors, grippers and manipulators. The sensors developed are targeted for prosthetic arm tactile sensing applications. Current work presents piezoresistive differential pressure sensors fabricated on flexible polyimide film or substrate. A unique technique to bond a flexible superstrate polyimide layer to a MEMS tactile sensor array is presented in this thesis. The sensor is made of aluminium oxide membrane layer with nichrome piezoresistors as the half-Wheatstone bridge elements. Four different types of sensor designs have been characterized to obtain gauge factor of thin film nichrome. The sensor arrays with and without the superstrate film were simulated for obtaining the maximum stress, average strain and deflection of the membrane. The maximum change in output voltage was 0.8 mV. The gauge factors calculated for tactile sensor with superstrate range between 2.2 to 7.8 and without superstrate range 1.5 to 5.7.

  10. Revertant mosaicism in the skin. (United States)

    Lai-Cheong, J E; McGrath, J A


    Revertant mosaicism is a naturally occurring phenomenon involving the spontaneous correction of a pathogenic mutation in a somatic cell. Revertant mosaicism is not a rare event and has been described in several inherited skin conditions, including various subtypes of epidermolysis bullosa. The recognition of revertant mosaicism paves the way for revertant therapy which represents a potentially exciting "natural gene therapy" option for genetic disorders. The skin provides a useful model for studying revertant mosaicism because it is readily accessible and easy to examine. In this paper, we provide an overview of revertant mosaicism and its relevance in genetic skin disorders.

  11. Skin-inspired electronic devices

    Directory of Open Access Journals (Sweden)

    Alex Chortos


    Full Text Available Electronic devices that mimic the properties of skin have potential important applications in advanced robotics, prosthetics, and health monitoring technologies. Methods for measuring tactile and temperature signals have progressed rapidly due to innovations in materials and processing methods. Imparting skin-like stretchability to electronic devices can be accomplished by patterning traditional electronic materials or developing new materials that are intrinsically stretchable. The incorporation of sensing methods with transistors facilitates large-area sensor arrays. While sensor arrays have surpassed the properties of human skin in terms of sensitivity, time response, and device density, many opportunities remain for future development.

  12. Sulfate transport in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Simonsen, K


    1. In short-circuited toad skin preparations exposed bilaterally to NaCl-Ringer's containing 1 mM SO2(-4), influx of sulfate was larger than efflux showing that the skin is capable of transporting sulfate actively in an inward direction. 2. This active transport was not abolished by substituting...... apical Na+ for K+. 3. Following voltage activation of the passive Cl- permeability of the mitochondria-rich (m.r.) cells sulfate flux-ratio increased to a value predicted from the Ussing flux-ratio equation for a monovalent anion. 4. In such skins, which were shown to exhibit vanishingly small leakage...

  13. [Non-irritating skin protector]. (United States)

    Gago Fornells, Manuel; García González, R Fernando; Gaztelu Valdés, Victoriana


    In this article, the authors describe the multiple uses a non irritating cutaneous protector has as an effective tool against the aggressions which peri-lesion skin and other at risk skins suffer when they are subject to constant and direct contact with secretions and liquids resulting from the use of dressings based on wet cures, or systems of continence related to ostomias, or in those patients who suffer mixed incontinence where diaper rash makes it difficult to maintain and care for the skin.

  14. Skin Treatments and Dermatological Procedures to Promote Youthful Skin


    Sator, Paul G


    The skin, the largest organ of the body, is the organ in which changes associated with aging are most visible. With increasing frequency, patients are requesting information and treatments that improve the appearance of their skin. Corresponding to this trend, there is an increasing number of products and methods available that claim to aid this pursuit. First, a change of the patient's lifestyle (eg, sun behavior, nicotine abuse, and nutrition) must take place. Only then may other methods be...

  15. Skin nonpenetrating sunscreens for cosmetic and pharmaceutical formulations. (United States)

    Touitou, Elka; Godin, Biana


    Ultraviolet (UV) solar radiation produces harmful effects on the skin including sunburn, local immunosuppression, skin photoaging, and cutaneous malignancies. Although application of sunscreens is the "gold standard" for protecting the skin from UV radiation, studies have shown that currently used sunscreens can cause adverse skin and systemic reactions, owing to their penetration into the viable cutaneous strata and to transdermal absorption. This paper presents new nonpermeating sunscreens (NPSUN) suitable for use in cosmetic and pharmaceutical products. The basic idea behind the design of the new photoprotectors was to immobilize UV-absorbing moieties in the Jojoba oil chemical backbone. The physicochemical characteristics of NPSUNs allow these derivatives to remain confined to the upper stratum corneum where the sunscreen molecule acts, with no further clearance to deeper dermal strata or systemic circulation. As an example, no permeation across the skin of methoxycinnamate-NPSUN was observed during 24-hour in vitro experiments, after topical application of either unformulated substances or of methoxycinnamate-NPSUNs formulated in oil-in-water cream, in water-in-oil cream, or in Jojoba oil. Another approach to increase the photoprotective effect against the UV radiation is targeting the delivery of alpha tocopherol into the deeper skin layers and across the cell membranes. This is necessary for optimal photoprotection and prevention of malignant processes. For this purpose, ethosomal vitamin E compositions were designed, characterized, and tested. Efficient intracellular and dermal accumulation of vitamin E from ethosomes was demonstrated. A good clinical strategy could be the use of NPSUNs during direct UV exposure followed by the application of alpha-tocopherol compositions after short- or long-term solar radiation.

  16. Skin temperature during sunbathing--relevance for skin cancer. (United States)

    Petersen, Bibi; Philipsen, Peter Alshede; Wulf, Hans Christian


    It has been found that exposure to heat and infrared radiation (IR) can be carcinogenic, and that a combination of ultraviolet radiation (UVR) and IR possibly amplifies carcinogenesis. To investigate how the skin temperature is affected by sunbathing, we measured the skin temperature on 20 healthy volunteers over 6 days' sun holiday in Egypt. Temperatures were measured with an infrared thermometer gun at 8 skin sites on the volunteers while they were indoors in the morning and when sunbathing during the day. Skin temperatures were higher during sunbathing (33.5 °C ± 2.1 °C) (mean ± SD) than when indoors in the morning (32.6 °C ± 1.4 °C) (mean ± SD) (P < 0.0001). The average skin temperature for men was higher than for women by 0.40 °C in the morning (P = 0.02) and by 0.44 °C during sunbathing (P < 0.0001). Our results show that sunbathing has an impact on skin temperature, which possibly by activation of the heat shock response, is likely to contribute to the immediate and delayed effects of UV in a way that has to be found out in future studies.

  17. Skin temperature during sunbathing--relevance for skin cancer

    DEFF Research Database (Denmark)

    Petersen, Bibi; Philipsen, Peter Alshede; Wulf, Hans Christian


    It has been found that exposure to heat and infrared radiation (IR) can be carcinogenic, and that a combination of ultraviolet radiation (UVR) and IR possibly amplifies carcinogenesis. To investigate how the skin temperature is affected by sunbathing, we measured the skin temperature on 20 healthy...... volunteers over 6 days' sun holiday in Egypt. Temperatures were measured with an infrared thermometer gun at 8 skin sites on the volunteers while they were indoors in the morning and when sunbathing during the day. Skin temperatures were higher during sunbathing (33.5 °C ± 2.1 °C) (mean ± SD) than when...... indoors in the morning (32.6 °C ± 1.4 °C) (mean ± SD) (P skin temperature for men was higher than for women by 0.40 °C in the morning (P = 0.02) and by 0.44 °C during sunbathing (P skin temperature, which possibly...

  18. Skin microbiome and skin disease: the example of rosacea. (United States)

    Picardo, Mauro; Ottaviani, Monica


    The imbalance and/or the perturbation of the microbial populations that colonize the skin and that contribute to its defense may represent one of the causes of the development of noninfectious skin diseases. Atopic dermatitis, psoriasis, acne, and rosacea can be listed among these kinds of pathologies. In particular, considering that microbes have been long addressed as having a role in rosacea, this common dermatosis can be an interesting model to evaluate the correlation between microbiome alterations and the occurrence of clinical manifestations. Different microorganisms have been suggested to have a role in rosacea, but no direct correlation with the incidence of the pathology has been clearly defined. Skin microbiome composition is crucial for the correct skin immune functions and recent findings indicate an abnormal activation of innate immune system associated with the rosacea. The enhanced expression of toll-like receptor 2 in the epidermis of rosacea patients can represent a possible explanation for the amplified inflammatory response to external stimuli observed during the disease. In addition, significantly higher small intestinal bacterial overgrowth prevalence in rosacea subjects has been found and its eradication has been associated with a regression of the skin lesions. In conclusion, both skin and gut microbiome seem to have a role, even if synergistic with other factors, in the pathogenesis of rosacea. A deeper knowledge of human microbiome composition and microbe-host interactions will contribute to clarify the mechanism of development of rosacea and possibly will provide innovative therapeutic approaches.

  19. Chronological age affects the permeation of fentanyl through human skin in vitro

    DEFF Research Database (Denmark)

    Holmgaard, R; Benfeldt, E; Sorensen, J A


    AIM: To study the influence of chronological age on fentanyl permeation through human skin in vitro using static diffusion cells. Elderly individuals are known to be more sensitive to opioids and obtain higher plasma concentrations following dermal application of fentanyl compared to younger...... individuals. The influence of age - as an isolated pharmacokinetic term - on the absorption of fentanyl has not been previously studied. METHOD: Human skin from 30 female donors was mounted in static diffusion cells, and samples were collected during 48 h. Donors were divided into three age groups: ... and old age groups: 5,922 and 4,050 ng, respectively). Furthermore, the lag time and absorption rate were different between the three groups, with a significantly higher rate in the young participants versus the oldest participants. CONCLUSION: We demonstrate that fentanyl permeates the skin of young...

  20. A diffusion approximation model of light transport in multilayered skin tissue (United States)

    Makropoulou, M.; Kaselouris, E.; Drakaki, E.; Serafetinides, A. A.; Sianoudis, J. A.


    In dermatology, biophotonic methods offer high sensitivity and non-invasive measurements of skin tissue optical properties, in various physiological and pathological conditions. There are numerous skin processes, which can be examined and characterized using diagnostic optical spectroscopy, as the monitoring of skin aging, diagnosis of benign and malignant cutaneous lesions, dosimetry in photodynamic therapy (PDT), etc. Several mathematical models have been used to calculate the tissue optical properties from experimental measurements and to predict the light propagation in soft tissues, like skin, based on transport theory or Monte Carlo modeling. This work analyses the phenomena which are observed experimentally during the irradiation of skin, such as the absorption, reflectance, scattering, fluorescence and transmission of laser light. The study was carried out on animal skin samples, extracted post-mortem. In this work we also tried to evaluate the utility of diffusion approximation modeling for measuring the light intensity distribution in the skin samples with cw visible laser beam (λ=632.8 nm). The diffusion theory model was tested for the simulation results of the spatial light distribution within a five-layer model of animal skin tissue. We have studied the dependence towards the depth and the radial distance of the photon density of the incident radiation.

  1. Phytases for improved iron absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Meyer, Anne S.


    Phytase enzymes present an alternative to iron supplements, because they have been shown to improve iron absorption by means of catalysing the degradation of a potent iron absorption inhibitor: phytic acid. Phytic acid is a hexaphosphate of inositol and is particularly prevalent in cereal grains,...

  2. Multifunctional hybrids for electromagnetic absorption

    Energy Technology Data Exchange (ETDEWEB)

    Huynen, I. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Quievy, N. [Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bailly, C. [Research Center in Micro and Nanoscopic Materials and Electronic Devices, CeRMiN, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Bollen, P. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Condensed Matter and Nanosciences (IMCN), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Mechanics, Materials and Civil Engineering (iMMC), Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Detrembleur, C. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium); Eggermont, S.; Molenberg, I. [Information and Communications Technologies, Electronics and Applied Mathematics (ICTEAM), Microwave Laboratory, Universite catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Thomassin, J.M.; Urbanczyk, L. [Center for Education and Research on Macromolecules (CERM), University of Liege, Sart-Tilman B6a, 4000 Liege (Belgium)


    Highlights: > EM absorption requires low dielectric constant and {approx}1 S/m electrical conductivity. > New hybrids were processed with CNT-filled polymer foam inserted in Al honeycomb. > The EM absorption in the GHz range is superior to any known material. > A closed form model is used to guide the design of the hybrid. > The architectured material is light with potential for thermal management. - Abstract: Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management.

  3. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.


    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in

  4. Percutaneous characterization of the insect repellent DEET and the sunscreen oxybenzone from topical skin application. (United States)

    Kasichayanula, Sreeneeranj; House, James D; Wang, Tao; Gu, Xiaochen


    The synergistic percutaneous enhancement between insect repellent DEET and sunscreen oxybenzone has been proven in our laboratory using a series of in vitro diffusion studies. In this study, we carried out an in vivo study to characterize skin permeation profiles from topical skin application of three commercially available repellent and sunscreen preparations. The correlation between skin disposition and drug metabolism was attempted by using data collected. Both DEET and oxybenzone permeated across the skin after the application and achieved substantial systemic absorption. Combined use of DEET and oxybenzone significantly enhanced the percutaneous penetration percentages (ranging 36-108%) due to mutual enhancement effects. Skin disposition indicated that DEET produced a faster transdermal permeation rate and higher systemic absorption extent, but oxybenzone formed a concentrated depot within the skin and delivered the content slowly over the time. In vivo AUCP/MRT of DEET and oxybenzone was increased by 37%/17% and 63%/10% when the two compounds were used together. No DEET was detected from the urine samples 48 h after the application. Tape stripping seemed to be a satisfactory approach for quantitative assessment of DEET and oxybenzone penetration into the stratum corneum. It was also concluded that pharmacological and toxicological perspectives from concurrent application of insect repellent and sunscreen products require further evaluation to ensure use efficacy and safety of these common consumer healthcare products.

  5. The skin-blanching assay. (United States)

    Smit, P; Neumann, H A M; Thio, H B


    The skin-blanching assay is used for the determination and bioequivalence of dermatologic glucocorticoids (GCs). The exact mechanism of the production of blanching is not fully understood, but it is considered that local vasoconstriction of the skin microvasculature and the consequent blood-flow reduction cause this phenomenon. Several factors influence skin blanching, including drug concentration, duration of application, nature of vehicle, occlusion, posture and location. The intensity of vasoconstriction can be measured in several ways: visual or quantitative methods, such as reflectance spectroscopy, thermography, laser Doppler velocimetry and chromametry. In literature, contradicting results in the correlation of the skin-blanching assay with different tests to determine GC sensitivity have been reported, limiting its clinical usefulness.

  6. Dry skin - self-care (United States)

    ... moisture Hot, dry air in desert environments Air conditioners that cool the air and remove moisture Taking ... scrubbing your skin. Shave right after bathing, when hair is soft. Wear soft, comfortable clothing next to ...

  7. Drugs Approved for Skin Cancer (United States)

    This page lists cancer drugs approved by the Food and Drug Administration (FDA) for skin cancer. The list includes generic names and brand names. The drug names link to NCI's Cancer Drug Information summaries.

  8. [Vitamin D and the skin]. (United States)

    Libon, F; Cavalier, E; Nikkels, A F


    Vitamin D is well known for its beneficial effects on phosphocalcic homeostasis. The discovery of the role of vitamin D in cancers, infections, cardiovascular or autoimmune pathologies have promoted interest for this molecule. Skin and vitamin D are closely related. The skin is not only the site of vitamin D synthesis, but also a target organ as calcitriol plays an important hormonal and regulatory role, acting on cell proliferation, differentiation and immunomodulation. Furthermore, vitamin D influences the incidence and therapeutic response of certain dermatoses. In addition, many medical situations, mainly dermatological, require strict photoprotection and may therefore indirectly be responsible for a vitamin D deficiency in patients. The current role of vitamin D in skin cancers, inflammatory and autoimmune skin diseases is summarized.

  9. Radiation Therapy for Skin Cancer (United States)

    ... make sure they are safe to use during radiation therapy. • Eat a balanced diet. If food tastes ... your fluid intake. • Treat the skin exposed to radiation with special care. Stay out of the sun, ...

  10. Skin Barrier Function and Allergens

    DEFF Research Database (Denmark)

    Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan


    The skin is an important barrier protecting us from mechanical insults, microorganisms, chemicals and allergens, but, importantly, also reducing water loss. A common hallmark for many dermatoses is a compromised skin barrier function, and one could suspect an elevated risk of contact sensitization...... and skin barrier status. Psoriasis has traditionally been regarded a Th1-dominated disease, but the discovery of Th17 cells and IL-17 provides new and interesting information regarding the pathogenesis of the disease. Research suggests an inverse relationship between psoriasis and CA, possibly due......) and Th2 (AD) have been proposed as an explanation. Finally, there is convincing evidence that exposure to irritants increases the risk of CS, and patients with ICD are, therefore, at great risk of developing CA. Skin irritation leads to the release of IL-1 and TNF-α, which affects the function of antigen...

  11. Vitamin D and skin cancer. (United States)

    Burns, Erin M; Elmets, Craig A; Yusuf, Nabiha


    Vitamin D signaling plays a key role in many important processes, including cellular proliferation, differentiation and apoptosis, immune regulation, hormone secretion and skeletal health. Furthermore, vitamin D production and supplementation have been shown to exert protective effects via an unknown signaling mechanism involving the vitamin D receptor (VDR) in several diseases and cancer types, including skin cancer. With over 3.5 million new diagnoses in 2 million patients annually, skin cancer is the most common cancer type in the United States. While ultraviolet B (UVB) radiation is the main etiologic factor for nonmelanoma skin cancer (NMSC), UVB also induces cutaneous vitamin D production. This paradox has been the subject of contradictory findings in the literature in regards to amount of sun exposure necessary for appropriate vitamin D production, as well as any beneficial or detrimental effects of vitamin D supplementation for disease prevention. Further clinical and epidemiological studies are necessary to elucidate the role of vitamin D in skin carcinogenesis.

  12. Moisturizers: Options for Softer Skin (United States)

    ... producing glands become less active. To keep your skin soft and well-hydrated, choose an oil-based moisturizer that contains petrolatum as the base, along with antioxidants or alpha hydroxy acids to combat wrinkles. These ...

  13. Discovery – Preventing Skin Cancer (United States)

    Cancer research includes stopping cancer before it spreads. NCI funded the development of the Melanoma Risk Assessment Tool and the ABC method. Both help to diagnose high-risk patients and prevent melanoma earlier in the fight against skin cancer.

  14. In vivo comparative documentation of skin hydration by confocal Raman microscopy, SkinSensor, Skicon, and NovaMeter (United States)

    Zhang, Guojin; Papillon, Aline; Ruvolo, Eduardo, Jr.; Bargo, Paulo R.; Kollias, Nikiforos


    The stratum corneum provides a vital physical barrier that protects against external insults and excessive internal water loss. Water activity is thought as a key factor to maintain proper skin barrier integrity via regulating enzyme activities and lipid phase behavior. Consequently, maintenance of an optimal hydration level in SC becomes an important clinical and cosmetic concern. The objective methods to assess SC hydration are based on either electrical or optical measurements. Electrical techniques used in the current study include high frequency conductance (Skicon), impedance (Nova DPM) and DC I-V curve (Skinsensor). Confocal Raman Microscopy was utilized to document water profile versus depth, and this technique is based on inelastic scattering of monochromatic light from different chemical species of skin. Water patches were applied on the 14 subjects' forearm for 20 minutes and 1.5 hrs. Skin hydration levels for individuals were documented by utilizing the mentioned above instruments in vivo. Results show that patterns of water profiles upon the hydration are significantly different among the individuals and these differences may be related to skin barrier function integrity. The intrinsic water content and water absorption upon the hydration were summed corresponding to different depths (3 μm and 15 μm) from the data obtained by confocal Raman microscopy. These results were correlated to the readings from electrical approaches. Superficial (3 μm) but not deeper layer (15 μm) water contents correlated well with the readings from SkinSensor. Neither depth measurements correlate well with the Skicon. There is strong correlation between the data acquired with Skicon and SkinSensor.

  15. Sexual hormones in human skin. (United States)

    Zouboulis, C C; Chen, W-C; Thornton, M J; Qin, K; Rosenfield, R


    The skin locally synthesizes significant amounts of sexual hormones with intracrine or paracrine actions. The local level of each sexual steroid depends upon the expression of each of the androgen- and estrogen-synthesizing enzymes in each cell type, with sebaceous glands and sweat glands being the major contributors. Sebocytes express very little of the key enzyme, cytochrome P450c17, necessary for synthesis of the androgenic prohormones dehydroepiandrosterone and androstenedione, however, these prohormones can be converted by sebocytes and sweat glands, and probably also by dermal papilla cells, into more potent androgens like testosterone and dihydrotestosterone. Five major enzymes are involved in the activation and deactivation of androgens in skin. Androgens affect several functions of human skin, such as sebaceous gland growth and differentiation, hair growth, epidermal barrier homeostasis and wound healing. Their effects are mediated by binding to the nuclear androgen receptor. Changes of isoenzyme and/or androgen receptor levels may have important implications in the development of hyperandrogenism and the associated skin diseases such as acne, seborrhoea, hirsutism and androgenetic alopecia. On the other hand, estrogens have been implicated in skin aging, pigmentation, hair growth, sebum production and skin cancer. Estrogens exert their actions through intracellular receptors or via cell surface receptors, which activate specific second messenger signaling pathways. Recent studies suggest specific site-related distribution of ERalpha and ERbeta in human skin. In contrast, progestins play no role in the pathogenesis of skin disorders. However, they play a major role in the treatment of hirsutism and acne vulgaris, where they are prescribed as components of estrogen-progestin combination pills and as anti-androgens. These combinations enhance gonadotropin suppression of ovarian androgen production. Estrogen-progestin treatment can reduce the need for shaving

  16. 19 CFR 12.63 - Seal-skin or sea-otter-skin waste. (United States)


    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Seal-skin or sea-otter-skin waste. 12.63 Section... OF THE TREASURY SPECIAL CLASSES OF MERCHANDISE Fur-Seal Or Sea-Otter Skins § 12.63 Seal-skin or sea-otter-skin waste. Seal-skin or sea-otter-skin waste composed of small pieces not large enough to...

  17. [New views about the skin]. (United States)

    Guimberteau, J-C; Delage, J-P; Wong, J


    As the follow up article to "Introduction to the knowledge of subcutaneous sliding system in humans" published in the "Annales de chirurgie plastique" we further investigate the architecture of the skin and comment on the subcutaneous multifibrillar and microvacuolar arrangements that provide form, mobility, adaptability and resistance to force of gravity. The study aimed to highlight the direct link between the skin and subcutaneous environment in dynamic living tissue. Through high resolution endoscopic observations made during live surgery it is revealed how microvacuoles and microspaces can provide dynamic structure and form during movement between the epidermis, dermis and hypodermis. The study reveals intriguing morphodynamics which are necessary to maintain mobility and continuity to neighboring tissues. The polyhedric design of the skin surface directly relates to multifibrillar pillars beneath the skin which dictate their patterning and movement. The concept of tissue continuity is realised by the chaotic and fractal organisation of multifibrils interlaced with cellular components which characteristics alter depending on the state of hydration. Understanding the integral arrangement that provides continuity of all the structures below the skin provides an appreciation to how skin behaves in relation to movement of the rest of the body.

  18. Pickering emulsions for skin decontamination. (United States)

    Salerno, Alicia; Bolzinger, Marie-Alexandrine; Rolland, Pauline; Chevalier, Yves; Josse, Denis; Briançon, Stéphanie


    This study aimed at developing innovative systems for skin decontamination. Pickering emulsions, i.e. solid-stabilized emulsions, containing silica (S-PE) or Fuller's earth (FE-PE) were formulated. Their efficiency for skin decontamination was evaluated, in vitro, 45min after an exposure to VX, one of the most highly toxic chemical warfare agents. Pickering emulsions were compared to FE (FE-W) and silica (S-W) aqueous suspensions. PE containing an oil with a similar hydrophobicity to VX should promote its extraction. All the formulations reduced significantly the amount of VX quantified on and into the skin compared to the control. Wiping the skin surface with a pad already allowed removing more than half of VX. FE-W was the less efficient (85% of VX removed). The other formulations (FE-PE, S-PE and S-W) resulted in more than 90% of the quantity of VX removed. The charge of particles was the most influential factor. The low pH of formulations containing silica favored electrostatic interactions of VX with particles explaining the better elimination from the skin surface. Formulations containing FE had basic pH, and weak interactions with VX did not improve the skin decontamination. However, these low interactions between VX and FE promote the transfer of VX into the oil droplets in the FE-PE.

  19. Radiation sterilization of skin allograft (United States)

    Kairiyama, E.; Horak, C.; Spinosa, M.; Pachado, J.; Schwint, O.


    In the treatment of burns or accidental loss of skin, cadaveric skin allografts provide an alternative to temporarily cover a wounded area. The skin bank facility is indispensable for burn care. The first human skin bank was established in Argentina in 1989; later, 3 more banks were established. A careful donor selection is carried out according to the national regulation in order to prevent transmissible diseases. As cadaveric human skin is naturally highly contaminated, a final sterilization is necessary to reach a sterility assurance level (SAL) of 10 -6. The sterilization dose for 106 batches of processed human skin was determined on the basis of the Code of Practice for the Radiation Sterilization of Tissue Allografts: Requirements for Validation and Routine Control (2004) and ISO 11137-2 (2006). They ranged from 17.6 to 33.4 kGy for bioburdens of >10-162.700 CFU/100 cm 2. The presence of Gram negative bacteria was checked for each produced batch. From the analysis of the experimental results, it was observed that the bioburden range was very wide and consequently the estimated sterilization doses too. If this is the case, the determination of a tissue-specific dose per production batch is necessary to achieve a specified requirement of SAL. Otherwise if the dose of 25 kGy is preselected, a standardized method for substantiation of this dose should be done to confirm the radiation sterilization process.

  20. Systemic antioxidants and skin health. (United States)

    Nguyen, Gloria; Torres, Abel


    Most dermatologists agree that antioxidants help fight free radical damage and can help maintain healthy skin. They do so by affecting intracellular signaling pathways involved in skin damage and protecting against photodamage, as well as preventing wrinkles and inflammation. In today's modern world of the rising nutraceutical industry, many people, in addition to applying topical skin care products, turn to supplementation of the nutrients missing in their diets by taking multivitamins or isolated, man-made nutraceuticals, in what is known as the Inside-Out approach to skin care. However, ingestion of large quantities of isolated, fragmented nutrients can be harmful and is a poor representation of the kind of nutrition that can be obtained from whole food sources. In this comprehensive review, it was found that few studies on oral antioxidants benefiting the skin have been done using whole foods, and that the vast majority of current research is focused on the study of compounds in isolation. However, the public stands to benefit greatly if more research were to be devoted toward the impact that physiologic doses of antioxidants (obtained from fruits, vegetables, and whole grains) can have on skin health, and on health in general.

  1. Estimation of skin phototypes with optical parameters: an experimental study using newly developed fibre optic detection device. (United States)

    Ries, F; Kapoustina, V; Kron, A; Fink, A; Rädle, M


    In an experimental study (October 2010 Mannheim Germany) with 99 Caucasian volunteers, the skin colour (L*, a*, b*) and the reflectance spectra of human skin were compared to the Fitzpatrick's sun-reactive skin photo types (SPT). For this purpose, the skin colour and the reflectance spectra of human skin were determined using non-invasive method with a newly developed fibre optic detection device. The device, based on reflectance spectroscopy, was designed and optimized using a commercial optical analysis Software. By means of the measured spectra of scattered light, the colour values and the absorption spectra of the skin were calculated. Neither any of the L*, a*, b* colour values nor any of the parameters of the absorbance spectra can be used alone to assess the skin type properly. Therefore, an ordinal logistic regression analysis was performed, using the statistical computing software r, to correlate the skin types with the measured optical parameters. It turned out that the detection device combined with the extended statistical analysis gives a better estimate of skin type in respect of the measured optical parameters than a procedure with only L*, a*, b* colour values. Even with the extended methodology, the procedure gives only a rough estimation of the skin type.

  2. Autoimmune Skin Diseases in the Dog


    Parker, W. M.


    Diagnoses of autoimmune skin diseases require very careful observation of the skin lesions, and selection of an intact vesicle for histopathological examination. If available, immunofluorescent studies can be very useful in confirming the diagnosis of autoimmune skin disease. Seven autoimmune skin diseases are briefly reviewed. Therapy must be aggressive and owner warned of the guarded prognosis.

  3. 7 CFR 51.1549 - Skinning. (United States)


    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Skinning. 51.1549 Section 51.1549 Agriculture... Standards for Grades of Potatoes 1 Skinning § 51.1549 Skinning. (a) The following definitions provide a basis for describing lots of potatoes as to the degree of skinning whenever description may...

  4. Gastrointestinal citrate absorption in nephrolithiasis (United States)

    Fegan, J.; Khan, R.; Poindexter, J.; Pak, C. Y.


    Gastrointestinal absorption of citrate was measured in stone patients with idiopathic hypocitraturia to determine if citrate malabsorption could account for low urinary citrate. Citrate absorption was measured directly from recovery of orally administered potassium citrate (40 mEq.) in the intestinal lavage fluid, using an intestinal washout technique. In 7 stone patients citrate absorption, serum citrate levels, peak citrate concentration in serum and area under the curve were not significantly different from those of 7 normal subjects. Citrate absorption was rapid and efficient in both groups, with 96 to 98% absorbed within 3 hours. The absorption of citrate was less efficient from a tablet preparation of potassium citrate than from a liquid preparation, probably due to a delayed release of citrate from wax matrix. However, citrate absorption from solid potassium citrate was still high at 91%, compared to 98% for a liquid preparation. Thus, hypocitraturia is unlikely to be due to an impaired gastrointestinal absorption of citrate in stone patients without overt bowel disease.

  5. Application of atomic absorption spectroscopy for detection of multimetal traces in low-voltage electrical marks. (United States)

    Jakubeniene, Marija; Zakaras, Algirdas; Minkuviene, Zita Nijole; Benoshys, Alvydas


    Application of atomic absorption spectroscopy to detect multimetal traces in injured skin is a promising tool for investigation of fatalities caused by electrocution. The present paper is aimed at testing the reliability of this method for metal traces detection in electric current marks and is focused on study of peculiarities of metal penetration into the skin exposed to a current impact. Bare aluminum wire, tin-lead coated copper multistrand wire, and zinc-plated steel rope were used to make electrical marks on pig skin. It is demonstrated that amount of copper, zinc, lead, and iron may serve as statistically reliable indicators for the type of wire, which caused the electrical mark, in spite of the background content of these metals in the skin without injury. Different penetration rates for different metals contained in the wire inflicting an electrical mark were observed.

  6. Quantity of ethanol absorption after excessive hand disinfection using three commercially available hand rubs is minimal and below toxic levels for humans


    Toma Cyril D; Kampf Guenter; Bieber Nora; Below Harald; Kramer Axel; Huebner Nils-Olaf; Assadian Ojan


    Abstract Background Despite the increasing promotion of alcohol-based hand rubs and the worldwide use of ethanol-based hand rubs in hospitals only few studies have specifically addressed the issue of ethanol absorption when repeatedly applied to human skin. The aim of this study was to assess if ethanol absorption occurs during hygienic and surgical hand disinfection using three different alcohol-based hand-rubs, and to quantify absorption levels in humans. Methods Twelve volunteers applied t...

  7. Skin interaction with absorbent hygiene products. (United States)

    Runeman, Bo


    Skin problems due to the use of absorbent hygiene products, such as diapers, incontinence pads, and feminine sanitary articles, are mostly due to climate or chafing discomfort. If these conditions are allowed to prevail, these may develop into an irritant contact dermatitis and eventually superficial skin infections. Skin humidity and aging skin are among the most significant predisposing and aggravating factors for dermatitis development. Improved product design features are believed to explain the decline in observed diaper dermatitis among infants. Where adult incontinence-related skin problems are concerned, it is very important to apply a holistic perspective to understand the influences due to the individual's incontinence level and skin condition, as well as the hygiene and skin care measures provided. Individuals with frail, sensitive skin or with skin diseases may preferably have to use high-quality products, equipped with superabsorbent polymers and water vapor-permeable back sheets, to minimize the risk of skin complications.

  8. Self-reported skin morbidity in Denmark

    DEFF Research Database (Denmark)

    Miller, Iben Marie; Zarchi, Kian; Ellervik, Christina


    Skin diseases are thought to be common in the general population. In 2004, a cross-sectional study in Norway, using a validated questionnaire for 18,770 individuals, revealed a high prevalence of skin diseases in the general population. To describe the prevalence of self-reported skin morbidities...... questionnaire. In total, 17.2% self-reported skin complaints. The most prominent self-reported skin complaint was itch with an overall prevalence of 6.5%. The skin morbidity most influenced by age was pimples. There was a uniform pattern showing fewer skin complaints with increasing education. Women reported...... skin morbidities more frequently than men. Participants in employment reported fewer skin morbidities compared to unemployed participants. Skin morbidities in Denmark are common, and the distribution of prevalence estimates in the Danish population parallel those of the Norwegian population, although...

  9. Total light absorption in graphene

    CERN Document Server

    Thongrattanasiri, Sukosin; de Abajo, F Javier Garcia


    We demonstrate that 100% light absorption can take place in a single patterned sheet of doped graphene. General analysis shows that a planar array of small lossy particles exhibits full absorption under critical-coupling conditions provided the cross section of each individual particle is comparable to the area of the lattice unit-cell. Specifically, arrays of doped graphene nanodisks display full absorption when supported on a substrate under total internal reflection, and also when lying on a dielectric layer coating a metal. Our results are relevant for infrared light detectors and sources, which can be made tunable via electrostatic doping of graphene.

  10. Quantitative and simultaneous non-invasive measurement of skin hydration and sebum levels (United States)

    Ezerskaia, Anna; Pereira, S. F.; Urbach, H. Paul; Verhagen, Rieko; Varghese, Babu


    We report a method on quantitative and simultaneous non-contact in-vivo hydration and sebum measurements of the skin using an infrared optical spectroscopic set-up. The method utilizes differential detection with three wavelengths 1720, 1750, and 1770 nm, corresponding to the lipid vibrational bands that lay “in between” the prominent water absorption bands. We have used an emulsifier containing hydro- and lipophilic components to mix water and sebum in various volume fractions which was applied to the skin to mimic different oily-dry skin conditions. We also measured the skin sebum and hydration values on the forehead under natural conditions and its variations to external stimuli. Good agreement was found between our experimental results and reference values measured using conventional biophysical methods such as Corneometer and Sebumeter. PMID:27375946

  11. Reactive skin decontamination lotion (RSDL) for the decontamination of chemical warfare agent (CWA) dermal exposure. (United States)

    Schwartz, M D; Hurst, C G; Kirk, M A; Reedy, S J D; Braue, E H


    Rapid decontamination of the skin is the single most important action to prevent dermal absorption of chemical contaminants in persons exposed to chemical warfare agents (CWA) and toxic industrial chemicals (TICs) as a result of accidental or intentional release. Chemicals on the skin may be removed by mechanical means through the use of dry sorbents or water. Recent interest in decontamination systems which both partition contaminants away from the skin and actively neutralize the chemical has led to the development of several reactive decontamination solutions. This article will review the recently FDA-approved Reactive Skin Decontamination Lotion (RSDL) and will summarize the toxicity and efficacy studies conducted to date. Evidence of RSDL's superior performance against vesicant and organophosphorus chemical warfare agents compared to water, bleach, and dry sorbents, suggests that RSDL may have a role in mass human exposure chemical decontamination in both the military and civilian arenas.

  12. In Vitro Skin Permeation of Osthol from Hydro-Alcohofic Gel Formulations

    Institute of Scientific and Technical Information of China (English)

    YUANZhen-ting; DINGPing-tian; LuBo; CHENDa-wei


    Aim To evaluate the in vitro percutaneous absorption behavior of osthol from a series of hydro-alcoholic gel formulations containing three penetration enhancers through excised human skin (stratum cormeum and epidermis,SCE). Methods Excised human skin was mounted in Franz-type diffusion cells. The samples withdrawn from the receptor cell were analyzed for osthol content by high-performance liquid chromatography (HPLC). Results The enhancers azone, menthol and chenopodium increased the osthol percutaneous steady-state fluxes 3.12, 2.00 and 1.25 times those of the enhancer-free formulations (controls), separately. Conclusions The main enhancement mechanism of the skin penetration enhancers azone, menthol and chenopodium is to destroy the barrier fimction of stratum corneum, reducing the resistance of drug transport through the skin and increasing the diffusion coefficients of osthol.

  13. Reconstruction of the penile skin loss due to 'radical' circumcision with a full thickness skin graft

    Directory of Open Access Journals (Sweden)

    Ignjatović Ivan


    Full Text Available Background. Excessive resection of penile skin is a rare but important complication of circumcision. Penis 'trapping' under the skin and consequent sexual dysfunction occur as a result. Case report. Excessive circumcision with complete resection of the penile skin is shown. Penis, trapped under the skin, was deliberated and skin defect was substituted with the full thickness skin graft. One year after the surgery penis has a good cosmetic appearance, adequate size and sexual function. Conclusion. Full thickness skin graft is a good option for augmentation of the penile skin loss in cases with intact hypodermal tissue and extensive skin loss, for the reconstruction in a single act.

  14. Validation model for Raman based skin carotenoid detection. (United States)

    Ermakov, Igor V; Gellermann, Werner


    Raman spectroscopy holds promise as a rapid objective non-invasive optical method for the detection of carotenoid compounds in human tissue in vivo. Carotenoids are of interest due to their functions as antioxidants and/or optical absorbers of phototoxic light at deep blue and near UV wavelengths. In the macular region of the human retina, carotenoids may prevent or delay the onset of age-related tissue degeneration. In human skin, they may help prevent premature skin aging, and are possibly involved in the prevention of certain skin cancers. Furthermore, since carotenoids exist in high concentrations in a wide variety of fruits and vegetables, and are routinely taken up by the human body through the diet, skin carotenoid levels may serve as an objective biomarker for fruit and vegetable intake. Before the Raman method can be accepted as a widespread optical alternative for carotenoid measurements, direct validation studies are needed to compare it with the gold standard of high performance liquid chromatography. This is because the tissue Raman response is in general accompanied by a host of other optical processes which have to be taken into account. In skin, the most prominent is strongly diffusive, non-Raman scattering, leading to relatively shallow light penetration of the blue/green excitation light required for resonant Raman detection of carotenoids. Also, sizable light attenuation exists due to the combined absorption from collagen, porphyrin, hemoglobin, and melanin chromophores, and additional fluorescence is generated by collagen and porphyrins. In this study, we investigate for the first time the direct correlation of in vivo skin tissue carotenoid Raman measurements with subsequent chromatography derived carotenoid concentrations. As tissue site we use heel skin, in which the stratum corneum layer thickness exceeds the light penetration depth, which is free of optically confounding chromophores, which can be easily optically accessed for in vivo RRS

  15. Skin Cancer and UV Protection

    Directory of Open Access Journals (Sweden)

    Tarbuk Anita


    Full Text Available The incidence of skin cancer is increasing by epidemic proportions. Basal cell cancer remains the most common skin neoplasm, and simple excision is generally curative. On the other hand, aggressive local growth and metastasis are common features of malignant melanoma, which accounts for 75% of all deaths associated with skin cancer. The primary cause of skin cancer is long exposure to solar ultraviolet radiation (UV-R crossed with the amount of skin pigmentation and family genetics. It is believed that in childhood and adolescence, 80% of UV-R gets absorbed while in the remaining, 20 % gets absorbed later in the lifetime. This suggests that proper and early photoprotection may reduce the risk of subsequent occurrence of skin cancer. Reducing the exposure time to sunlight, using sunscreens and protective textiles are the three ways of UV protection. Most people think that all the clothing will protect them, but it does not provide full sun screening properties. Literature sources claim that only 1/3 of the spring and summer collections tested give off proper UV protection. This is very important during the summer months, when UV index is the highest. Fabric UV protection ability highly depends on large number of factors such as type of fiber, fabric surface, construction, porosity, density, moisture content, type and concentration of dyestuff, fluorescent whitening agents, UV-B protective agents (UV absorbers, as well as nanoparticles, if applied. For all of these reasons, in the present paper, the results of UV protecting ability according to AS/NZS 4399:1996 will be discussed to show that standard clothing materials are not always adequate to prevent effect of UV-R to the human skin; and to suggest the possibilities for its improvement for this purpose enhancing light conversion and scattering. Additionally, the discrepancy in UV protection was investigated in distilled water as well as Adriatic Sea water.

  16. Skin Findings in Williams Syndrome (United States)

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


    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. PMID:24920525

  17. The current management of skin tears. (United States)

    Xu, Xiaoti; Lau, Kwan; Taira, Breena R; Singer, Adam J


    Each year, there are more than 1 million skin tears among the elderly and disabled. Because of their fragile nature, management of skin tears can be very challenging. Methods of wound closure should minimize additional trauma to the skin and promote an optimal wound healing environment while minimizing the risk of infection. The current article reviews the etiology, risk factors, classification, and therapeutic options for treating skin tears. We also review preventive measures to help reduce the incidence of skin tears.

  18. MR imaging manifestations of skin tumors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong-hyon; Kim, Jee Young [The Catholic University of Korea, Department of Diagnostic Radiology, St. Vincent' s Hospital, Suwon, Gyeonggi-do (Korea); Chun, Kyung Ah [The Catholic University of Korea, Department of Diagnostic Radiology, Uijeongbu St. Mary Hospital, Uijeongbu, Gyeonggi-do (Korea); Jee, Won-Hee [The Catholic University of Korea, Department of Diagnostic Radiology, Kangnam St. Mary' s Hospital, Seoul (Korea); Sung, Mi-Sook [The Catholic University of Korea, Department of Diagnostic Radiology, Holy family Hospital, Bucheon, Gyeonggi-do (Korea)


    In this study, we evaluated MR imaging findings of skin tumors and categorized them into four types: (1) discrete mass lesions of the dermis and epidermis, (2) mass lesions of the subcutis with or without abutment to the skin, (3) diffuse or localized skin thickening without a true mass, and (4) a skin mass with bone destruction. The categorization of MR images may be useful in the differential diagnosis of skin tumors. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Vinicius M. [Laboratory of Molecular Modeling and Design, Faculty of Pharmacy, Federal University of Goiás, Goiânia, GO 74605-220 (Brazil); Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Muratov, Eugene [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Laboratory of Theoretical Chemistry, A.V. Bogatsky Physical–Chemical Institute NAS of Ukraine, Odessa 65080 (Ukraine); Fourches, Denis [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States); Strickland, Judy; Kleinstreuer, Nicole [ILS/Contractor supporting the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM), P.O. Box 13501, Research Triangle Park, NC 27709 (United States); Andrade, Carolina H. [Laboratory of Molecular Modeling and Design, Faculty of Pharmacy, Federal University of Goiás, Goiânia, GO 74605-220 (Brazil); Tropsha, Alexander, E-mail: [Laboratory for Molecular Modeling, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599 (United States)


    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 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 skin

  20. Fatty acid transport protein 4 is dispensable for intestinal lipid absorption in mice. (United States)

    Shim, Jien; Moulson, Casey L; Newberry, Elizabeth P; Lin, Meei-Hua; Xie, Yan; Kennedy, Susan M; Miner, Jeffrey H; Davidson, Nicholas O


    FA transport protein 4 (FATP4), one member of a multigene family of FA transporters, was proposed as a major FA transporter in intestinal lipid absorption. Due to the fact that Fatp4(-/-) mice die because of a perinatal skin defect, we rescued the skin phenotype using an FATP4 transgene driven by a keratinocyte-specific promoter (Fatp4(-/-);Ivl-Fatp4(tg/+) mice) to elucidate the role of intestinal FATP4 in dietary lipid absorption. Fatp4(-/-);Ivl-Fatp4(tg/+) mice and wild-type littermates displayed indistinguishable food consumption, growth, and weight gain on either low or high fat (Western) diets, with no differences in intestinal triglyceride (TG) absorption or fecal fat losses. Cholesterol absorption and intestinal TG absorption kinetics were indistinguishable between the genotypes, although Western diet fed Fatp4(-/-);Ivl-Fatp4(tg/+) mice showed a significant increase in enterocyte TG and FA content. There was no compensatory upregulation of other FATP family members or any other FA or cholesterol transporters in Fatp4(-/-);Ivl-Fatp4(tg/+) mice. Furthermore, although serum cholesterol levels were lower in Fatp4(-/-);Ivl-Fatp4(tg/+) mice, there was no difference in hepatic VLDL secretion in-vivo or in hepatic lipid content on either a chow or Western diet. Taken together, our studies find no evidence for a physiological role of intestinal FATP4 in dietary lipid absorption in mice.

  1. Palladium nanoparticles exposure: Evaluation of permeation through damaged and intact human skin. (United States)

    Larese Filon, Francesca; Crosera, Matteo; Mauro, Marcella; Baracchini, Elena; Bovenzi, Massimo; Montini, Tiziano; Fornasiero, Paolo; Adami, Gianpiero


    The intensified use of palladium nanoparticles (PdNPs) in many chemical reactions, jewellery, electronic devices, in car catalytic converters and in biomedical applications lead to a significant increase in palladium exposure. Pd can cause allergic contact dermatitis when in contact with the skin. However, there is still a lack of toxicological data related to nano-structured palladium and information on human cutaneous absorption. In fact, PdNPs, can be absorbed through the skin in higher amounts than bulk Pd because NPs can release more ions. In our study, we evaluated the absorption of PdNPs, with a size of 10.7 ± 2.8 nm, using intact and damaged human skin in Franz cells. 0.60 mg cm(-2) of PdNPs were applied on skin surface for 24 h. Pd concentrations in the receiving solutions at the end of experiments were 0.098 ± 0.067 μg cm(-2) and 1.06 ± 0.44 μg cm(-2) in intact skin and damaged skin, respectively. Pd flux permeation after 24 h was 0.005 ± 0.003 μg cm(-2) h(-1) and 0.057 ± 0.030 μg cm(-2) h(-1) and lag time 4.8 ± 1.7 and 4.2 ± 3.6 h, for intact and damaged skin respectively. This study indicates that Pd can penetrate human skin.

  2. Ultrasound biomicroscopy measurement of skin thickness change induced by cosmetic treatment with ultrasound stimulation. (United States)

    Mak, Tak-Man; Huang, Yan-Ping; Wang, Li-Ke; Zheng, Yong-Ping


    Moisturizing creams and lotions are commonly used in daily life for beauty and treatment of different skin conditions such as dryness and wrinkling, and ultrasound stimulation has been used to enhance the delivery of ingredients into skin. However, there is a lack of convenient methods to study the effect of ultrasound stimulation on lotion absorption by skin in vivo. Ultrasound biomicroscopy was adopted as a viable tool in this study to investigate the effectiveness of ultrasound stimulation on the enhancement of lotion delivery into skin. The forearm skin of 10 male and 10 female young subjects was tested at three different sites, including two lotion treatment sites with (Ultrasound Equipment - UE ON) and without (UE OFF) ultrasound stimulation and a control site without any lotion treatment. 1 MHz ultrasound with a duty cycle of 1.7%, a spatial peak temporal peak pressure of 195 kPa and an average power of 0.43 W was used for the stimulation. The skin thickness before, immediately after (0 min), and 15 and 30 min after the treatment was measured by an ultrasound biomicroscopic system (55 MHz). It was found that the skin thickness significantly increased immediately after the lotion treatment for both UE ON (from 1.379 ± 0.187 mm to 1.466 ± 0.182 mm, pultrasound stimulation was more effective for the female subjects than the male subjects (7.6 ± 2.3% vs. 5.4 ± 2.0% immediately after treatment, p=0.017). In conclusion, this study demonstrated that ultrasound biomicroscopy was a feasible method for studying the effectiveness of lotion treatment in vivo, and ultrasound stimulation was effective to enhance the rate of lotion absorption into skin.

  3. Bent Electro-Absorption Modulator

    DEFF Research Database (Denmark)


    The present invention relates to a method and a device for modulating optical signals based on modulating bending losses in bend, quantum well semiconductor waveguide sections. The complex refractive index of the optical active semiconducting components of the waveguide section is modulated...... components and the applied electric field in relation to the frequency of the modulated radiation, the bending losses (and possibly coupling losses) will provide extinction of light guided by the bent waveguide section. The refractive index contract may be modulated while keeping the absorption coefficient...... substantially constant and small, whereby the guided light can be modulated only by bending losses. Alternatively, the invention may be applied to enhance the extinction ratio of existing absorption modulators such as Electro-Absorption Modulators (EAMs) in which case extinction by absorption and extinction...

  4. Circadian Regulation of Macronutrient Absorption. (United States)

    Hussain, M Mahmood; Pan, Xiaoyue


    Various intestinal functions exhibit circadian rhythmicity. Disruptions in these rhythms as in shift workers and transcontinental travelers are associated with intestinal discomfort. Circadian rhythms are controlled at the molecular level by core clock and clock-controlled genes. These clock genes are expressed in intestinal cells, suggesting that they might participate in the circadian regulation of intestinal functions. A major function of the intestine is nutrient absorption. Here, we will review absorption of proteins, carbohydrates, and lipids and circadian regulation of various transporters involved in their absorption. A better understanding of circadian regulation of intestinal absorption might help control several metabolic disorders and attenuate intestinal discomfort associated with disruptions in sleep-wake cycles.

  5. Perforating disorders of the skin

    Directory of Open Access Journals (Sweden)

    Kalpana Arora


    Full Text Available Background: Perforating disorders of the skin, is an often overlooked entity characterized by transepidermal elimination of material from the upper dermis and are classified histopathologically according to the type of epidermal disruption and the nature of the eliminated material. They include Kyrle′s disease, perforating folliculitis, reactive perforating collagenosis, and elastosis perforans serpiginosa. Aim: The aim of this study was to delineate the clinical and histopathological features of perforating disorders of the skin. Materials and Methods: In our study, we reviewed last 2 years skin biopsies received by us. Hematoxylin and eosin sections were re-examined and histochemical stainings (elastic van Gieson and Masson trichrome stains were also used for histopathological evaluation. Results: We reviewed five cases of perforating disorders of skin which included two cases of Kyrle′s disease, two cases of reactive perforating collagenosis and a single case of perforating folliculitis. Two patients had family history of perforating dermatosis in their siblings and three had associated systemic disease. Conclusion: Perforating disorders of the skin should be considered when ulcer with keratotic plugs is found.


    Directory of Open Access Journals (Sweden)



    Full Text Available The ozone absorption in raw water entering the main ozonization step at the Belgrade drinking water supply plant was investigated in a continuous stirred tank reactor (CSTR. A slow chemical reaction rate of dissolved ozone and pollutants present in raw water have been experimentally determined. The modified Hatta number was defined and calculated as a criterion which determines whether and to which extent the reactions of ozone and pollutants influence the rate of the pure physical ozone absorption.

  7. Absorption Of Dietary Lipid Components


    Abdulkadir Hurşit


    Although the digestion and absorption of lipids that are necessary for the survival of living organisms are well known in general terms, nevertheless how different lipids to be digested, how it is distributed into the bloodstream, and how to be used by the cells, are unknown issues by most non specialist people. In recent years, knowledge of lipid digestion and absorption has expanded considerably. More insight has been gained in the mechanism of action of H + pump as a transport system in fa...

  8. Subgap Absorption in Conjugated Polymers (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.


    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  9. Femtosecond pulsed laser ablation to enhance drug delivery across the skin. (United States)

    Garvie-Cook, Hazel; Stone, James M; Yu, Fei; Guy, Richard H; Gordeev, Sergey N


    Laser poration of the skin locally removes its outermost, barrier layer, and thereby provides a route for the diffusion of topically applied drugs. Ideally, no thermal damage would surround the pores created in the skin, as tissue coagulation would be expected to limit drug diffusion. Here, a femtosecond pulsed fiber laser is used to porate mammalian skin ex vivo. This first application of a hollow core negative curvature fiber (HC-NCF) to convey a femtosecond pulsed, visible laser beam results in reproducible skin poration. The effect of applying ink to the skin surface, prior to ultra-short pulsed ablation, has been examined and Raman spectroscopy reveals that the least, collateral thermal damage occurs in inked skin. Pre-application of ink reduces the laser power threshold for poration, an effect attributed to the initiation of plasma formation by thermionic electron emission from the dye in the ink. Poration under these conditions significantly increases the percutaneous permeation of caffeine in vitro. Dye-enhanced, plasma-mediated ablation of the skin is therefore a potentially advantageous approach to enhance topical/transdermal drug absorption. The combination of a fiber laser and a HC-NCF, capable of emitting and delivering femtosecond pulsed, visible light, may permit a compact poration device to be developed.

  10. Cutaneous absorption of Oleander: Fact or fiction

    Directory of Open Access Journals (Sweden)

    Senthilkumaran S


    Full Text Available Cardiac conduction disorders following oral ingestion of Oleander plant materials were documented earlier. Transcutaneous absorption of yellow oleander (Thevetia peruviana leaf extract applied over non intact skin (raw wound resulting in reversible cardiac conduction disorder observed in four healthy males who were free from any other systemic or electrolyte or metabolic disorders or exposure to pesticide or toxins is reported for the first time. Their hematological, biochemical, clinical, and echocardiogram status were within normal limits and free of any abnormalities. One among the four, presented for weakness and breathlessness (class II. He had bradycardia with Mobitz II block and hypotension without any other demonstrable localizing signs. The other three were identified in the community and without any symptoms. However, their ECG revealed bradycardia with Mobitz I block in two and complete heart block in the other. All of the four recovered well without any untoward events. Hence, it is suggested that physicians and practitioners have to elicit history and route of administration of unconventional therapy, whenever they are confronted with clinical challenges and during medical emergencies before embarking final decision.

  11. The optical properties of mouse skin in the visible and near infrared spectral regions. (United States)

    Sabino, Caetano P; Deana, Alessandro M; Yoshimura, Tania M; da Silva, Daniela F T; França, Cristiane M; Hamblin, Michael R; Ribeiro, Martha S


    Visible and near-infrared radiation is now widely employed in health science and technology. Pre-clinical trials are still essential to allow appropriate translation of optical methods into clinical practice. Our results stress the importance of considering the mouse strain and gender when planning pre-clinical experiments that depend on light-skin interactions. Here, we evaluated the optical properties of depilated albino and pigmented mouse skin using reproducible methods to determine parameters that have wide applicability in biomedical optics. Light penetration depth (δ), absorption (μa), reduced scattering (μ's) and reduced attenuation (μ't) coefficients were calculated using the Kubelka-Munk model of photon transport and spectrophotometric measurements. Within a broad wavelength coverage (400-1400nm), the main optical tissue interactions of visible and near infrared radiation could be inferred. Histological analysis was performed to correlate the findings with tissue composition and structure. Disperse melanin granules present in depilated pigmented mouse skin were shown to be irrelevant for light absorption. Gender mostly affected optical properties in the visible range due to variations in blood and abundance of dense connective tissue. On the other hand, mouse strains could produce more variations in the hydration level of skin, leading to changes in absorption in the infrared spectral region. A spectral region of minimal light attenuation, commonly referred as the "optical window", was observed between 600 and 1350nm.

  12. Ectodermal Dysplasia Skin Fragility Syndrome

    Directory of Open Access Journals (Sweden)

    Ayça Alan Atalay


    Full Text Available Ectodermal dysplasia-skin fragility syndrome (EDSFS is a rare autosomal recessive genodermatosis first described in 1997 by Mc Grath. EDSFS results from loss of function mutations in plakophilin-1 (PKP1. PKP1 is a structural component of desmosomes, cellcell adhesion complexes. It is also found as a nuclear protein in several cell types that are lack of desmosomes. In skin, however, PKP1 expression is confined mainly to suprabasal keratinocytes and the outer root sheath of hair follicules. Loss of function mutation in PKP1 leads to extensive skin fragility, bullae and erosions following minor trauma, focal keratoderma with painful fissures, alopecia, and nail dystrophy. In some patients hypohidrosis may also be seen. EDSFS is now considered as a specific suprabasal form of epidermolysis bullosa simplex. In this report we describe a 20 year old EDSFS case.

  13. Animal models of skin regeneration. (United States)

    Gawronska-Kozak, Barbara; Grabowska, Anna; Kopcewicz, Marta; Kur, Anna


    Cutaneous injury in the majority of vertebrate animals results in the formation of a scar in the post-injured area. Scar tissues, although beneficial for maintaining integrity of the post-wounded region often interferes with full recovery of injured tissues. The goal of wound-healing studies is to identify mechanisms to redirect reparative pathways from debilitating scar formation to regenerative pathways that lead to normal functionality. To perform such studies models of regeneration, which are rare in mammals, are required. In this review we discussed skin regenerative capabilities present in lower vertebrates and in models of skin scar-free healing in mammals, e.g. mammalian fetuses. However, we especially focused on the attributes of two unusual models of skin scar-free healing capabilities that occur in adult mammals, that is, those associated with nude, FOXN1-deficient mice and in wild-type African spiny mice.

  14. Management of Acute Skin Trauma

    Institute of Scientific and Technical Information of China (English)

    Joel W. Beam


    @@ Acute skin trauma (ie, abrasions, avulsions, blisters, incisions, lacerations, and punctures) is common among individuals involved in work, recreational, and athletic activities. Appropriate management of these wounds is important to promote healing and lessen the risk of cross-contamination and infection. Wound management techniques have undergone significant changes in the past 40 years but many clinicians continue to manage acute skin trauma with long-established, traditional techniques (ie, use of hydrogen peroxide, adhesive strips/patches, sterile gauze, or no dressing) that can delay healing and increase the risk of infection. The purpose of this review is to discuss evidence-based cleansing, debridement, and dressing techniques for the management of acute skin trauma.

  15. Surgical skin-marking techniques. (United States)

    Granick, M S; Heckler, F R; Jones, E W


    Surgical skin-marking inks and dyes are in everyday use for designing and planning incisions in plastic and reconstructive surgery. We have traced the historical development of surgical skin-marking techniques from ancient times to the present. The biochemical characteristics of the commonly used marking agents are discussed. A three-part experiment utilizing a pig model was carried out to test the tissue inflammatory response to the various dyes and inks when used intradermally as tattoos, the persistence of such tattoos, and the ease of skin erasure for each of eight stains. Methylene blue and gentian violet are recommended as the best all-purpose marking agents. The use of proprietary inks is discouraged.

  16. Skin Ultrasound in Kaposi Sarcoma. (United States)

    Carrascosa, R; Alfageme, F; Roustán, G; Suarez, M D


    The use of ultrasound imaging has recently been increasing in numerous dermatologic diseases. This noninvasive technique provides additional details on the structure and vascularization of skin lesions. Kaposi sarcoma is a vascular tumor that typically arises in the skin and mucosas. It can spread to lymph nodes and internal organs. We performed B-mode and color Doppler ultrasound studies in 3 patients with a clinical diagnosis of Kaposi sarcoma confirmed by histological examination. We found differences in the ultrasound pattern between nodular and plaque lesions, in both B-mode and color Doppler. We believe that skin ultrasound imaging could be a useful technique for studying cutaneous Kaposi sarcoma, providing additional information on the structural and vascular characteristics of the lesion.

  17. Development of an in vivo animal model for skin penetration in hairless rats assessed by mass balance

    DEFF Research Database (Denmark)

    Simonsen, Lene; Petersen, Mads B; Benfeldt, Eva


    acid and (14)C-butyl salicylate were topically applied. Rapid and differentiated percutaneous absorption of both compounds were shown by urinary excretion data. For (14)C-salicylic acid the amount on the skin surface, in the stratum corneum and in the viable skin was determined. Total mass balance...... rat and free mobility throughout the test period. By consecutive tape stripping, monitored by measurements of transepidermal water loss and confirmed by histological examination of skin biopsies, 10 tape strippings were found to remove the stratum corneum completely. For assessment of the model, (14)C-salicylic...

  18. Influence of Clothing Fabrics on Skin Microcirculation

    Institute of Scientific and Technical Information of China (English)

    CHENG Ling; PAN Ning; ZHAO Lian-ying; HUAUNG Gu


    This study investigated the effects of clothing fabric on human skin microcirculation. Once skin is covered with a clothing fabric, human sensations, namely, coolness, warmth, softness, and roughness, are amused immediately, and the cutaneous micrecireulation may be changed consequently. Since the complex relationships of the human skin, the environment, and the clothing, there is few publication focusing on the physiological responses of the skin to the fabrics. In this paper, a Laser Doppler Flowmetry (LDF) was used to test the dynamic responses of the skin blood flow when the fabric was placed on the skin. Effects of different fabrics on the skin blood flux were investigated. The results show that cold stimulation of fabric has remarkable influences on the skin blood flux, and the surface properties of fabric are of importance to affect the human skin blood flow.

  19. Fat-soluble vitamin intestinal absorption: absorption sites in the intestine and interactions for absorption. (United States)

    Goncalves, Aurélie; Roi, Stéphanie; Nowicki, Marion; Dhaussy, Amélie; Huertas, Alain; Amiot, Marie-Josèphe; Reboul, Emmanuelle


    The interactions occurring at the intestinal level between the fat-soluble vitamins A, D, E and K (FSVs) are poorly documented. We first determined each FSV absorption profile along the duodenal-colonic axis of mouse intestine to clarify their respective absorption sites. We then investigated the interactions between FSVs during their uptake by Caco-2 cells. Our data show that vitamin A was mostly absorbed in the mouse proximal intestine, while vitamin D was absorbed in the median intestine, and vitamin E and K in the distal intestine. Significant competitive interactions for uptake were then elucidated among vitamin D, E and K, supporting the hypothesis of common absorption pathways. Vitamin A also significantly decreased the uptake of the other FSVs but, conversely, its uptake was not impaired by vitamins D and K and even promoted by vitamin E. These results should be taken into account, especially for supplement formulation, to optimise FSV absorption.

  20. Skin scoring in systemic sclerosis

    DEFF Research Database (Denmark)

    Zachariae, Hugh; Bjerring, Peter; Halkier-Sørensen, Lars


    Forty-one patients with systemic sclerosis were investigated with a new and simple skin score method measuring the degree of thickening and pliability in seven regions together with area involvement in each region. The highest values were, as expected, found in diffuse cutaneous systemic sclerosis...... (type III SS) and the lowest in limited cutaneous systemic sclerosis (type I SS) with no lesions extending above wrists and ancles. A positive correlation was found to the aminoterminal propeptide of type III procollagen, a serological marker for synthesis of type III collagen. The skin score...

  1. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke


    The skin is a strong and flexible organ with barrier properties essential for maintaining homeostasis and thereby human life. Characterizing this barrier is the ability to prevent some chemicals from crossing the barrier while allowing others, including medicinal products, to pass at varying rates......-through diffusion cells) as well as in vivo methods (microdialysis and microperfusion). Then follows a discussion with examples of how different characteristics of the skin (age, site and integrity) and of the penetrants (size, solubility, ionization, logPow and vehicles) affect the kinetics of percutaneous...

  2. Clinical utility of skin karyotype

    Directory of Open Access Journals (Sweden)

    Luiza E. Dorfman


    Full Text Available ABSTRACTWe report the case of a patient with Patau syndrome, diagnosed by skin karyotype, emphasizing the applications and importance of this test. The pregnancy morphology ultrasound showed face defects and of central nervous system and heart chambers asymmetry. In the postnatal evaluation it was identified microcephaly, single central nostril, and other malformations. We performed skin karyotype that resulted in full trisomy 13. Our report highlights the possibility of performing karyotype examination in cases when it is no longer possible to obtain a blood sample, thus providing the correct diagnosis and genetic counseling for the family.

  3. Percutaneous absorption of several chemicals, some pesticides included, in the red-winged blackbird (United States)

    Rogers, J.G.; Cagan, R.H.; Kare, M.R.


    Percutaneous absorption in vivo through the skin of the feet of the red-winged blackbird (Agelaius phoeniceus) has been investigated. Absorption after 18-24 hours exposure to 0.01 M solutions of salicylic acid, caffeine, urea, 2,4-D, dieldrin, diethylstilbesterol, and DDT was measured. Of these, only DDT and diethylstilbesterol were not absorbed to a measurable degree. The solvents ethanol, dimethylsulfoxide (DMSO), and vegetable oil were compared with water in their effects on the absorption ofcaffeine, urea, and salicylic acid. Ethanol, DMSO,and oil each decreased percutaneous absorption of salicylic acid. DMSO increased absorption of caffeine, and ethanol had no effect on it. Neither DMSO nor ethanol affected penetration of urea. Partition coefficients (K) (epidermis/water) were determined for all seven penetrants. Compounds with higher values of K showed lower percutaneous absorption. These findings suggest that K may be useful to predict percutaneous absorption in vivo. It appears unlikely that percutaneous absorption contributes greatly to the body burden of 2,4-D and dieldrin in A. phoeniceus.

  4. [Skin-sparing mastectomies: how to avoid skin necrosis?]. (United States)

    Delbaere, M; Delaporte, T; Toussoun, G; Delay, E


    Skin-sparing mastectomy (SSM) has emerged as the surgical technique best adapted to the treatment of early breast cancers or breast cancer recurrences after conservative treatment; the technique is particularly appreciated by the patients who had been expecting the development of immediate, high-quality breast reconstruction for over 15 years. SSM preserves anatomical landmarks on the skin surface (notably the under-breast fold and the conical shape of the breast). The procedure must be performed by a skilled surgical team in order to maximize the quality of breast resection and reconstruction, particularly to avoid postoperative complications, notably damage to blood vessels within the skin flap and prosthesis infection. These complications generally affect the cosmetic outcome of the reconstruction, with serious short-term and long-term consequences for the acceptability of the surgical procedure, and may sometimes compromise the delivery of adjuvant treatments (either chemo- or radiotherapy). Based on our previous experience (1000 new cases since 1992), we will compare the advantages and drawbacks of the procedure, discuss its indications, describe the clinical situations encountered and the various specific interventions available, as well as the methods to reduce the risks of tissue damage and skin necrosis.

  5. [Occupational skin diseases in medical personnel]. (United States)


    Occupational skin diseases develop mostly in certain occupational groups at risk. The authors studied features of occupational skin diseases in medical personnel examined over 2003-2007. During this time, occupational skin disease was diagnosed in 118 individuals out of which 24 (20.3%) were medical staffers. All 24 examinees suffered from occupational allergic skin conditions. Most common causes of these were medicines, latex, desinfectants. Nurses are most prone to skin conditions (91.67%). Special risk group covers surgeons, psychiatrists and dentists. As medical staffers are occupational risk group for occupational skin conditions, diagnosed allergic dermatoses in them should be considered as having possible occupational occupational origin.

  6. Skin health promotion effects of natural beta-glucan derived from cereals and microorganisms: a review. (United States)

    Du, Bin; Bian, Zhaoxiang; Xu, Baojun


    β-Glucans are natural cell wall polysaccharides found in yeast, fungi (including mushrooms), some bacteria, seaweeds and cereals. Natural β-glucans possess many health promotion effects on human health, such as anti-tumor, anti-diabetes, anti-infection, lowering blood cholesterol and immune-modulating properties. These effects have been reviewed previously. However, skin health promotion of β-glucan derived from cereals and microorganisms has received little attention. This review focuses on antioxidant activity, anti-wrinkle activity, anti-ultraviolet light, wound healing, and moisturizing effect and skin permeation absorption of β-glucan. Furthermore, applications of β-glucan in cosmetics are also discussed.

  7. Vitamin D and the skin. (United States)

    Shahriari, Mona; Kerr, Philip E; Slade, Karren; Grant-Kels, Jane E


    Vitamin D is a fat-soluble nutrient that humans obtain through the diet and by synthesis in the skin upon exposure to ultraviolet B. Vitamin D is then converted by the liver to 25-hydroxyvitamin D, its major circulating form. This form is the best indicator of vitamin D nutritional status and is easily measured. Under the influence of parathyroid hormone, the kidney then converts 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D, the biologically active, hormonal form of the nutrient that is important in the metabolism of calcium and phosphorus and is critical in building and maintaining healthy bones. Many cell types outside of the skeletal system, including various cells in the skin, also express the vitamin D receptor. In addition, many cell types convert circulating 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D for local use. This metabolite has been shown to exert potent effects on cellular differentiation, cellular proliferation, and immune regulation. It is theorized that by these mechanisms vitamin D and its analogues are effective treatment options for psoriasis and other skin diseases. Insufficient vitamin D nutritional status has been associated with a host of other diseases, most notably cancer. There is evidence that supplementation with vitamin D reduces the overall incidence of cancer, although current evidence is insufficient to prove a causative effect. Sunscreen use blocks the ability of the skin to photosynthesize vitamin D, although the effect this has on the vitamin D status of the general population is unclear.

  8. A disappearing neonatal skin lesion.

    LENUS (Irish Health Repository)

    Hawkes, Colin Patrick


    A preterm baby girl was noted at birth to have a firm, raised, non-tender skin lesion located over her right hip. She developed three similar smaller lesions on her ear, buttock and right knee. All lesions had resolved by 2 months of age.

  9. Skin Rashes and Other Problems (United States)

    ... glands overproduce.Self CareTry using hydrocortisone cream or selenium sulfide shampoo on the sore areas. See your ... your doctor. Actinic keratoses may lead to skin cancer.Start OverDiagnosisThis may be a KELOID, an overgrown ...

  10. Chloride channels in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E


    A study of the voltage and time dependence of a transepithelial Cl- current in toad skin (Bufo bufo) by the voltage-clamp method leads to the conclusion that potential has a dual role for Cl- transport. One is to control the permeability of an apical membrane Cl-pathway, the other is to drive Cl...

  11. Self-inflicted skin lesions

    DEFF Research Database (Denmark)

    Ring, Hans Christian; Smith, Matthias Nybro; Jemec, Gregor B E


    The current literature on the management of self-inflicted skin lesions points to an overall paucity of treatments with a high level of evidence (randomized controlled trials, controlled trials, or meta-analyses). In order to improve the communication between dermatologists and mental health...

  12. Skin Autofluorescence and Glycemic Variability

    NARCIS (Netherlands)

    Noordzij, M. J.; Lefrandt, J. D.; Graaff, R.; Smit, A. J.


    Background: Accumulation of advanced glycation end products (AGEs) is accelerated during glycemic and oxidative stress and is an important predictor of complications in diabetes mellitus (DM). Study Design: Here we both review and present original data on the relationship between skin autofluorescen

  13. Reference Values of Skin Autofluorescence

    NARCIS (Netherlands)

    Koetsier, M.; Lutgers, H. L.; de Jonge, C.; Links, T. P.; Smit, A. J.; Graaff, R.


    Background: Skin autofluorescence (AF) as measured with the AGE Reader (DiagnOptics Technologies, Groningen, The Netherlands) is a noninvasive prognostic marker in diabetes mellitus and other diseases with increased cardiovascular risk. This study provides reference values of healthy Caucasian contr

  14. Enhanced chlorhexidine skin penetration with eucalyptus oil

    Directory of Open Access Journals (Sweden)

    Worthington Tony


    Full Text Available Abstract Background Chlorhexidine digluconate (CHG is a widely used skin antiseptic, however it poorly penetrates the skin, limiting its efficacy against microorganisms residing beneath the surface layers of skin. The aim of the current study was to improve the delivery of chlorhexidine digluconate (CHG when used as a skin antiseptic. Method Chlorhexidine was applied to the surface of donor skin and its penetration and retention under different conditions was evaluated. Skin penetration studies were performed on full-thickness donor human skin using a Franz diffusion cell system. Skin was exposed to 2% (w/v CHG in various concentrations of eucalyptus oil (EO and 70% (v/v isopropyl alcohol (IPA. The concentration of CHG (μg/mg of skin was determined to a skin depth of 1500 μm by high performance liquid chromatography (HPLC. Results The 2% (w/v CHG penetration into the lower layers of skin was significantly enhanced in the presence of EO. Ten percent (v/v EO in combination with 2% (w/v CHG in 70% (v/v IPA significantly increased the amount of CHG which penetrated into the skin within 2 min. Conclusion The delivery of CHG into the epidermis and dermis can be enhanced by combination with EO, which in turn may improve biocide contact with additional microorganisms present in the skin, thereby enhancing antisepsis.

  15. The Microbiota of the Human Skin. (United States)

    Egert, Markus; Simmering, Rainer


    The aim of this chapter is to sum up important progress in the field of human skin microbiota research that was achieved over the last years.The human skin is one of the largest and most versatile organs of the human body. Owing to its function as a protective interface between the largely sterile interior of the human body and the highly microbially contaminated outer environment, it is densely colonized with a diverse and active microbiota. This skin microbiota is of high importance for human health and well-being. It is implicated in several severe skin diseases and plays a major role in wound infections. Many less severe, but negatively perceived cosmetic skin phenomena are linked with skin microbes, too. In addition, skin microorganisms, in particular on the human hands, are crucial for the field of hygiene research. Notably, apart from being only a potential source of disease and contamination, the skin microbiota also contributes to the protective functions of the human skin in many ways. Finally, the analysis of structure and function of the human skin microbiota is interesting from a basic, evolutionary perspective on human microbe interactions.Key questions in the field of skin microbiota research deal with (a) a deeper understanding of the structure (species inventory) and function (physiology) of the healthy human skin microbiota in space and time, (b) the distinction of resident and transient skin microbiota members,

  16. Cleansing Formulations That Respect Skin Barrier Integrity

    Directory of Open Access Journals (Sweden)

    Russel M. Walters


    Full Text Available Surfactants in skin cleansers interact with the skin in several manners. In addition to the desired benefit of providing skin hygiene, surfactants also extract skin components during cleansing and remain in the stratum corneum (SC after rinsing. These side effects disrupt SC structure and degrade its barrier properties. Recent applications of vibrational spectroscopy and two-photon microscopy in skin research have provided molecular-level information to facilitate our understanding of the interaction between skin and surfactant. In the arena of commercial skin cleansers, technologies have been developed to produce cleansers that both cleanse and respect skin barrier. The main approach is to minimize surfactant interaction with skin through altering its solution properties. Recently, hydrophobically modified polymers (HMPs have been introduced to create skin compatible cleansing systems. At the presence of HMP, surfactants assemble into larger, more stable structures. These structures are less likely to penetrate the skin, thereby resulting in less aggressive cleansers and the integrity of the skin barrier is maintained. In this paper, we reviewed our recent findings on surfactant and SC interactions at molecular level and provided an overview of the HM technology for developing cleansers that respect skin barrier.

  17. Biologic activities of molecular chaperones and pharmacologic chaperone imidazole-containing dipeptide-based compounds: natural skin care help and the ultimate challenge: implication for adaptive responses in the skin. (United States)

    Babizhayev, Mark A; Nikolayev, Gennady M; Nikolayeva, Juliana G; Yegorov, Yegor E


    Accumulation of molecular damage and increased molecular heterogeneity are hallmarks of photoaged skin and pathogenesis of human cutaneous disease. Growing evidence demonstrates the ability of molecular chaperone proteins and of pharmacologic chaperones to decrease the environmental stress and ameliorate the oxidation stress-related and glycation disease phenotypes, suggesting that the field of chaperone therapy might hold novel treatments for skin diseases and aging. In this review, we examine the evidence suggesting a role for molecular chaperone proteins in the skin and their inducer and protecting agents: pharmacologic chaperone imidazole dipeptide-based agents (carcinine and related compounds) in cosmetics and dermatology. Furthermore, we discuss the use of chaperone therapy for the treatment of skin photoaging diseases and other skin pathologies that have a component of increased glycation and/or free radical-induced oxidation in their genesis. We examine biologic activities of molecular and pharmacologic chaperones, including strategies for identifying potential chaperone compounds and for experimentally demonstrating chaperone activity in in vitro and in vivo models of human skin disease. This allows the protein to function and traffic to the appropriate location in the skin, thereby increasing protein activity and cellular function and reducing stress on skin cells. The benefits of imidazole dipeptide antioxidants with transglycating activity (such as carcinine) in skin care are that they help protect and repair cell membrane damage and help retain youthful, younger-looking skin. All skin types will benefit from daily, topical application of pharmacologic chaperone antioxidants, anti-irritants, in combination with water-binding protein agents that work to mimic the structure and function of healthy skin. General strategies are presented addressing ground techniques to improve absorption of usually active chaperone proteins and dipeptide compounds, include

  18. Simulation of fluorescent measurements in the human skin (United States)

    Meglinski, Igor V.; Sinichkin, Yurii P.; Utz, Sergei R.; Pilipenko, Helena A.


    Reflectance and fluorescence spectroscopy are successfully used for skin disease diagnostics. Human skin optical parameters are defined by its turbid, scattering properties with nonuniform absorption and fluorescence chromophores distribution, its multilayered structure, and variability under different physiological and pathological conditions. Theoretical modeling of light propagation in skin could improve the understanding of these condition and may be useful in the interpretation of in vivo reflectance and autofluorescence (AF) spectra. Laser application in medical optical tomography, tissue spectroscopy, and phototherapy stimulates the development of optical and mathematical light-tissue interaction models allowing to account the specific features of laser beam and tissue inhomogeneities. This paper presents the version of a Monte Carlo method for simulating of optical radiation propagation in biotissue and highly scattering media, allowing for 3D geometry of a medium. The simulation is based on use of Green's function of medium response to single external pulse. The process of radiation propagation is studied in the area with given boundary conditions, taking into account the processes of reflection and refraction at the boundaries of layers inside the medium under study. Results of Monte Carlo simulation were compared with experimental investigations and demonstrated good agreement.

  19. Dietary Hyaluronic Acid Migrates into the Skin of Rats

    Directory of Open Access Journals (Sweden)

    Mariko Oe


    Full Text Available Hyaluronic acid is a constituent of the skin and helps to maintain hydration. The oral intake of hyaluronic acid increases water in the horny layer as demonstrated by human trials, but in vivo kinetics has not been shown. This study confirmed the absorption, migration, and excretion of 14C-labeled hyaluronic acid (14C-hyaluronic acid. 14C-hyaluronic acid was orally or intravenously administered to male SD rats aged 7 to 8 weeks. Plasma radioactivity after oral administration showed the highest level 8 hours after administration, and orally administered 14C-hyaluronic acid was found in the blood. Approximately 90% of 14C-hyaluronic acid was absorbed from the digestive tract and used as an energy source or a structural constituent of tissues based on tests of the urine, feces, expired air, and cadaver up to 168 hours (one week after administration. The autoradiographic results suggested that radioactivity was distributed systematically and then reduced over time. The radioactivity was higher in the skin than in the blood at 24 and 96 hours after administration. The results show the possibility that orally administered hyaluronic acid migrated into the skin. No excessive accumulation was observed and more than 90% of the hyaluronic acid was excreted in expired air or urine.

  20. Mercury Levels in Locally Manufactured Mexican Skin-Lightening Creams

    Directory of Open Access Journals (Sweden)

    Luz O. Leal


    Full Text Available Mercury is considered one of the most toxic elements for plants and animals. Nevertheless, in the Middle East, Asia and Latin America, whitening creams containing mercury are being manufactured and purchased, despite their obvious health risks. Due to the mass distribution of these products, this can be considered a global public health issue. In Mexico, these products are widely available in pharmacies, beauty aid and health stores. They are used for their skin lightening effects. The aim of this work was to analyze the mercury content in some cosmetic whitening creams using the cold vapor technique coupled with atomic absorption spectrometry (CV-AAS. A total of 16 skin-lightening creams from the local market were investigated. No warning information was noted on the packaging. In 10 of the samples, no mercury was detected. The mercury content in six of the samples varied between 878 and 36,000 ppm, despite the fact that the U.S. Food and Drug Administration (FDA has determined that the limit for mercury in creams should be less than 1 ppm. Skin creams containing mercury are still available and commonly used in Mexico and many developing countries, and their contents are poorly controlled.

  1. Absorption characteristics of bacteriorhodopsin molecules

    Indian Academy of Sciences (India)

    H K T Kumar; K Appaji Gowda


    The bacteriorhodopsin molecule absorbs light and undergoes a series of structural transformation following a well-defined photocycle. The complex photocycle is transformed to an equivalent level diagram by considering the lifetime of the intermediate states. Assuming that only and states are appreciably populated at any instant of time, the level diagram is further simplified to two-level system. Based on the rate equations for two-level system, an analytic expression for the absorption coefficient of bacteriorhodopsin molecule is derived. It is applied to study the behaviour of absorption coefficient of bacteriorhodopsin film in the visible wavelength region of 514 nm. The dependence of absorption coefficient of bacteriorhodopsin film on the thickness of the film, total number density of active molecules and initial number density of molecules in -state is presented in the graphical form.

  2. How Is Melanoma Skin Cancer Diagnosed? (United States)

    ... Cancer Early Detection, Diagnosis, and Staging Tests for Melanoma Skin Cancer Most melanomas are brought to a ... New in Melanoma Skin Cancer Research? Biopsies of melanoma that may have spread Biopsies of areas other ...

  3. Turbine vane with high temperature capable skins

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Jay A [Oviedo, FL


    A turbine vane assembly includes an airfoil extending between an inner shroud and an outer shroud. The airfoil can include a substructure having an outer peripheral surface. At least a portion of the outer peripheral surface is covered by an external skin. The external skin can be made of a high temperature capable material, such as oxide dispersion strengthened alloys, intermetallic alloys, ceramic matrix composites or refractory alloys. The external skin can be formed, and the airfoil can be subsequently bi-cast around or onto the skin. The skin and the substructure can be attached by a plurality of attachment members extending between the skin and the substructure. The skin can be spaced from the outer peripheral surface of the substructure such that a cavity is formed therebetween. Coolant can be supplied to the cavity. Skins can also be applied to the gas path faces of the inner and outer shrouds.

  4. Skin Segmentation Based on Graph Cuts

    Institute of Scientific and Technical Information of China (English)

    HU Zhilan; WANG Guijin; LIN Xinggang; YAN Hong


    Skin segmentation is widely used in many computer vision tasks to improve automated visualiza-tion. This paper presents a graph cuts algorithm to segment arbitrary skin regions from images. The detected face is used to determine the foreground skin seeds and the background non-skin seeds with the color probability distributions for the foreground represented by a single Gaussian model and for the background by a Gaussian mixture model. The probability distribution of the image is used for noise suppression to alle-viate the influence of the background regions having skin-like colors. Finally, the skin is segmented by graph cuts, with the regional parameter y optimally selected to adapt to different images. Tests of the algorithm on many real wodd photographs show that the scheme accurately segments skin regions and is robust against illumination variations, individual skin variations, and cluttered backgrounds.

  5. Skin Bioprinting: Impending Reality or Fantasy? (United States)

    Ng, Wei Long; Wang, Shuai; Yeong, Wai Yee; Naing, May Win


    Bioprinting provides a fully automated and advanced platform that facilitates the simultaneous and highly specific deposition of multiple types of skin cells and biomaterials, a process that is lacking in conventional skin tissue-engineering approaches. Here, we provide a realistic, current overview of skin bioprinting, distinguishing facts from myths. We present an in-depth analysis of both current skin bioprinting works and the cellular and matrix components of native human skin. We also highlight current limitations and achievements, followed by design considerations and a future outlook for skin bioprinting. The potential of bioprinting with converging opportunities in biology, material, and computational design will eventually facilitate the fabrication of improved tissue-engineered (TE) skin constructs, making bioprinting skin an impending reality.

  6. Diabetic lipohypertrophy delays insulin absorption. (United States)

    Young, R J; Hannan, W J; Frier, B M; Steel, J M; Duncan, L J


    The effect of lipohypertrophy at injection sites on insulin absorption has been studied in 12 insulin-dependent diabetic patients. The clearance of 125I-insulin from sites with lipohypertrophy was significantly slower than from complementary nonhypertrophied sites (% clearance in 3 h, 43.8 +/- 3.5 +/- SEM) control; 35.3 +/- 3.9 lipohypertrophy, P less than 0.05). The degree of the effect was variable but sufficient in several patients to be of clinical importance. Injection-site lipohypertrophy is another factor that modifies the absorption of subcutaneously injected insulin.

  7. Quasistellar Objects Intervening Absorption Lines

    CERN Document Server

    Charlton, J C; Charlton, Jane C.; Churchill, Christopher W.


    We briefly review, at a level appropriate for graduate students and non-specialists, the field of quasar absorption lines (QALs). Emphasis is on the intervening absorbers. We present the anatomy of a quasar spectrum due to various classes of intervening absorption systems, and a brief historical review of each absorber class (Lyman-alpha forest and Lyman limit systems, and metal-line and damped Lyman-alpha absorbers). We also provide several heuristic examples on how the physical properties of both the intergalactic medium and the gaseous environments associated with earlier epoch galaxies can be inferred from QALs. The evolution of these environments from z=4 are discussed.

  8. Facial skin care products and cosmetics. (United States)

    Draelos, Zoe Diana


    Facial skin care products and cosmetics can both aid or incite facial dermatoses. Properly selected skin care can create an environment for barrier repair aiding in the re-establishment of a healing biofilm and diminution of facial redness; however, skin care products that aggressively remove intercellular lipids or cause irritation must be eliminated before the red face will resolve. Cosmetics are an additive variable either aiding or challenging facial skin health.

  9. Forensic identification using skin bacterial communities


    FIERER Noah; Lauber, Christian L.; Zhou, Nick; McDonald, Daniel; Costello, Elizabeth K.; Knight, Rob


    Recent work has demonstrated that the diversity of skin-associated bacterial communities is far higher than previously recognized, with a high degree of interindividual variability in the composition of bacterial communities. Given that skin bacterial communities are personalized, we hypothesized that we could use the residual skin bacteria left on objects for forensic identification, matching the bacteria on the object to the skin-associated bacteria of the individual who touched the object....

  10. Nanoscale alterations of corneocytes indicate skin disease

    DEFF Research Database (Denmark)

    Franz, J; Beutel, M; Gevers, K


    BACKGROUND: The skin barrier protects the organism against exogenous stressors and simultaneously prevents excessive water loss. While the delicate regulation of skin barrier is not completely understood, morphological and histological evaluation remain key features of clinical investigations. Here...... dermatitis, a common inflammatory skin condition. CONCLUSION: The presence of these corneocyte-nanostructures might be used as a diagnostic parameter for skin disorders - even in cases below a clinical threshold....

  11. Occupational skin cancer may be underreported

    DEFF Research Database (Denmark)

    Carøe, Tanja Korfitsen; Ebbehøj, Niels Erik; Wulf, Hans Christian


    Skin cancer may, in some cases, be caused by occupational exposures. The aim of this study was to investigate the prevalence of and exposures leading to occupationally induced skin cancers in Denmark during a ten-year period.......Skin cancer may, in some cases, be caused by occupational exposures. The aim of this study was to investigate the prevalence of and exposures leading to occupationally induced skin cancers in Denmark during a ten-year period....

  12. Skin Cancer of the Head and Neck


    Ouyang, Yun-Hsuan


    The majority of skin cancers of the head and neck are nonmelanoma skin cancers (NMSC). Basal cell carcinoma and squamous cell carcinoma are the most frequent types of NMSC. Malignant melanoma is an aggressive neoplasm of skin, and the ideal adjuvant therapy has not yet been found, although various options for treatment of skin cancer are available to the patient and physician, allowing high cure rate and excellent functional and cosmetic outcomes. Sunscreen protection and early evaluation of ...

  13. Ceramides and barrier function in healthy skin


    Jungerstedt, J; Hellgren, Lars; Drachmann, Tue; Høgh, Julie Kaae; Jemec, GBE; Agner, T


    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal ...

  14. Nanocarriers for skin delivery of cosmetic antioxidants


    Lucia Montenegro


    The demand of natural skin care products is steadily growing since consumers perceive them as safe. Currently, cosmetic manufacturers are focusing their efforts on developing innovative natural products to address skin-aging signs, thus meeting consumers’ needs of healthy appearance and well-being. To prevent or treat skin aging, topical supplementation with antioxidant is regarded as one of the most promising strategies. However, most antioxidants presently used in skin care formulations sho...

  15. Whole-skin electron treatment: patient skin dose distribution

    Energy Technology Data Exchange (ETDEWEB)

    Fraass, B.A.; Roberson, P.L.; Glatstein, E.


    Low-energy electron irradiation of the whole skin is used to treat skin diseases such as mycosis fungoides. The literature on the related dosimetry concentrates almost exclusively on idealized conditions, such as the ''in-air'' distribution of radiation and the dose received by body-shaped phantoms. The results of a detailed study of dose to five patients, using measurements from thermoluminescent dosimeters, are reported. The dose to different points on the trunk was fairly uniform, while there were significant deviations from uniformity for the arms, legs, and head. The data show that in-air measurements are of limited value as a measure of the uniformity of the dose received by the patient.

  16. Aerosol Absorption Measurements in MILAGRO. (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.


    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  17. Electrochemical Skin Conductance Correlates with Skin Nerve Fiber Density

    Directory of Open Access Journals (Sweden)

    Peter Novak


    Full Text Available Purpose: Electrochemical skin conductance (ESC using reverse iontophoresis and chronoamperometry has been used to evaluate abnormal function of small fibers. How ESC correlates with loss of small fibers in skin is unclear.Methods: This was a prospective, blinded study. The primary outcome measure was the correlation between ESC at the feet and results of skin biopsies including epidermal nerve fiber density (ENFD and sweat gland nerve fiber density (SGNFD at the distal leg. ESC, ENFD and SGNFD data were normalized by adjusting for weight. The secondary outcome measures were the correlation between ESC and the following variables: quantitative sudomotor axon reflex test (QSART and symptom scales (neuropathy, pain and autonomic.Results: 81 patients ((mean±sd: age=53.3±17.3, men/women=25/56 were enrolled in the study. ESC was reduced in subjects with abnormally low ENFD (ENFD normal/abnormal, ESC = 1.17±0.27/0.87±0.34 µSiemens/kg, p<0.0008 and abnormally low SGNFD (SGNFD normal/abnormal ESC=1.09±0.34/,0.78±0.3 µSiemens/kg,p<0.0003. ESC correlated with ENFD (ρ=0.73, p=0.0001 and SGNFD (ρ=0.64, p=0.0001. ESC did not correlate with symptom scales. Conclusion: ESC is diminished in subjects who have a reduced number of small fibers in the skin and the ESC reduction is proportional to ENFD and SGNFD. ESC can be useful in detecting loss of small nerve fibers.

  18. Skin Cancer Rates by Race and Ethnicity (United States)

    ... Trends Behavior Rates What CDC Is Doing Skin Cancer Prevention Progress Report The Burning Truth Initiative A Base Tan Is Not a Safe Tan Tanned Skin Is Not Healthy Skin Controlled Tanning Is Not Safe Tanning Guidelines for School ... Melanoma Surveillance in the U.S. Related Links ...

  19. What Causes Our Skin to Age? (United States)

    ... may help prevent damage that leads to premature skin aging. Findings from research studies also suggest that a diet containing lots of ... dehydrates the skin, and in time, damages the skin. This can make us look ... from a few studies suggest that moderate exercise can improve circulation and ...

  20. In vitro and in vivo percutaneous absorption of seleno-L-methionine, an antioxidant agent, and other selenium species

    Institute of Scientific and Technical Information of China (English)

    Chih-hung LIN; Chia-lang FANG; Saleh A AL-SUWAYEH; Shih-yun YANG; Jia-you FANG


    To investigate the in vitro and in vivo percutaneous absorption of seleno-L-methionine (Se-L-M),an ultraviolet (UV)-protecting agent,from aqueous solutions.Methods:Aqueous solutions of Se-L-M were prepared in pH 4,8,and 10.8 buffers.The pH 8 buffer contained 30% glycerol,propylene glycol (PG) and polyethylene glycol (PEG) 400.The in vitro skin permeation of Se-L-M via porcine skin and nude mouse skin was measured and compared using Franz diffusion cells.The in vivo skin tolerance study was performed,which examined transepidermal water loss (TEWL),skin pH and erythema.Results:In the excised porcine skin,the flux was 0.1,11.4 and 8.2 μg·cm-2·h-1 for the pH 4,8,and 10.8 buffers,respectively.A linear correlation between the flux and skin deposition was determined.According to permeation across skin with different treatments (stripping,delipidation,and ethanol treatments),it was determined that the intracellular route comprised the predominant pathway for Se-L-M permeation from pH 8 buffer.Aqueous solutions of seleno-DL-methionine (Se-DL-M),selenium sulfide and selenium-containing quantum dot nanoparticles were also used as donor systems.The DL form showed a lower flux (7.0 vs 11.4 μg·cm2·h-1) and skin uptake (23.4 vs 47.3 μg/g) as compared to the L form,indicating stereoselective permeation of this compound.There was no or only negligible permeation of selenium sulfide and quantum dots into and across the skin.With in vivo topical application for 4 and 8 h,the skin deposition of Se-L-M was about 7 μg/g,and values were comparable to each other.The topical application of Se-L-M for up to 5 d did not caused apparent skin irritation.However,slight inflammation of the dermis was noted according to the histopathological examination.Conclusion:Se-L-M was readily absorbed by the skin in both the in vitro and in vivo experiments.The established profiles of Se-L-M skin absorption will be helpful in developing topical products of this compound.

  1. An increase in [Ca2+]i activates basolateral chloride channels and inhibits apical sodium channels in frog skin epithelium

    DEFF Research Database (Denmark)

    Brodin, Birger; Rytved, K A; Nielsen, R


    The aim of this study was to investigate the mechanisms by which increases in free cytosolic calcium ([Ca2+]i) cause a decrease in macroscopic sodium absorption across principal cells of the frog skin epithelium. [Ca2+]i was measured with fura-2 in an epifluorescence microscope set-up, sodium...

  2. [Skin to skin contact and breast-feeding after birth: not always without risk!

    NARCIS (Netherlands)

    Matthijsse, P.R.; Semmekrot, B.A.; Liem, K.D.


    Skin-to-skin contact after birth is propagated to facilitate breast-feeding and mother-child bonding. We describe two term infants with sudden unexpected postnatal collapse (SUPC) during skin-to-skin contact. The infants were found with abnormal colour, hypotonia and apnoea, in a prone position on t

  3. Xenobiotic metabolism in human skin and 3D human skin reconstructs: A review

    NARCIS (Netherlands)

    Gibbs, S.; Sandt, J.J.M. van de; Merk, H.F.; Lockley, D.J.; Pendlington, R.U.; Pease, C.K.


    In this review, we discuss and compare studies of xenobiotic metabolism in both human skin and 3D human skin reconstructs. In comparison to the liver, the skin is a less studied organ in terms of characterising metabolic capability. While the skin forms the major protective barrier to environmental

  4. Dermatology of the head and neck: skin cancer and benign skin lesions. (United States)

    Halem, Monica; Karimkhani, Chanté


    Skin lesions are extremely common, and early detection of dangerous lesions makes skin cancer one of the most highly curable malignancies. By simply becoming aware of common lesions and their phenotypic presentation, dental professionals are empowered to detect suspicious dermatologic lesions in unaware patients. This article serves as an introduction to skin cancer and benign skin lesions for dental professionals.

  5. Exercise, Intestinal Absorption, and Rehydration

    Institute of Scientific and Technical Information of China (English)


    @@ KEYPOINTS 1. The proximal small intestine (duodenum & jejunum) is the primary site of fluid absorption. It absorbs about 50% to 60% of any given fluid load. The colon or large intestine absorbs approximately 80 to 90% of the fluid it receives, but accounts for only about 15% of the total fluid load.

  6. Migrant labor absorption in Malaysia. (United States)

    Nayagam, J


    The use of migrant workers to ease labor shortages caused by rapid industrialization in Malaysia during the twentieth century is examined. "This paper will focus on: (1) the extent, composition and distribution of migrant workers; (2) the labor shortage and absorption of migrant workers; and (3) the role of migrant workers in the government's economic restructuring process."

  7. Neutron Absorption in Geological Material (United States)

    Løvhøiden, G.; Andersen, E.


    Thermal neutron absorption cross section of geological samples is determined with the steady state neutron source method. Cross section measurements of North Sea sediments demonstrate that also materials with high contents of clay minerals may be investigated with the steady state method.

  8. Oxygen Absorption in Cooling Flows. (United States)



    The inhomogeneous cooling flow scenario predicts the existence of large quantities of gas in massive elliptical galaxies, groups, and clusters that have cooled and dropped out of the flow. Using spatially resolved, deprojected X-ray spectra from the ROSAT PSPC, we have detected strong absorption over energies approximately 0.4-0.8 keV intrinsic to the central approximately 1&arcmin; of the galaxy NGC 1399, the group NGC 5044, and the cluster A1795. These systems have among the largest nearby cooling flows in their respective classes and low Galactic columns. Since no excess absorption is indicated for energies below approximately 0.4 keV, the most reasonable model for the absorber is warm, collisionally ionized gas with T=105-106 K in which ionized states of oxygen provide most of the absorption. Attributing the absorption only to ionized gas reconciles the large columns of cold H and He inferred from Einstein and ASCA with the lack of such columns inferred from ROSAT and also is consistent with the negligible atomic and molecular H inferred from H i and CO observations of cooling flows. The prediction of warm ionized gas as the product of mass dropout in these and other cooling flows can be verified by Chandra and X-Ray Multimirror Mission.

  9. Absorption Efficiency of Receiving Antennas

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Frandsen, Aksel


    A receiving antenna with a matched load will always scatter some power. This paper sets an upper and a lower bound on the absorption efficiency (absorbed power over sum of absorbed and scattered powers), which lies between 0 and 100% depending on the directivities of the antenna and scatter...

  10. Clustering of absorption line systems

    CERN Document Server

    Petitjean, P


    Absorption line systems are luminosity unbiased tracers of the spatial distribution of baryons over most of the history of the Universe. I review the importance of studying the clustering properties of the absorbers and the impact of VLT in this subject. The primary aim of the project is to track the evolution of the structures of the Universe back in time.

  11. Electromodulated absorption in smoky quartz

    NARCIS (Netherlands)

    Brom, W.E. van den; Volger, J.


    The optical absorption coefficient of “smoky” quartz (containing aluminium) can be modulated by applying an electric field. The effect saturates at high fields and low temperatures and reaches a maximum at 535 nm. The results are discussed in terms of a model consisting of a colour centre, dipolar i

  12. Absorptive capacity and smart companies

    Directory of Open Access Journals (Sweden)

    Patricia Moro González


    Full Text Available Purpose: The current competitive environment is substantially modifying the organizations’ learning processes due to a global increase of available information allowing this to be transformed into knowledge. This opportunity has been exploited since the nineties by the tools of “Business Analytics” and “Business Intelligence” but, nevertheless, being integrated in the study of new organizational capacities engaged in the process of creating intelligence inside organizations is still an outstanding task. The review of the concept of absorptive capacity and a detailed study from the perspective of this new reality will be the main objective of study of this paper.Design/methodology/approach: By comparing classical absorptive capacity and absorptive capacity from the point of view of information management tools in each one of the three stages of the organizational learning cycle, some gaps of the former are overcome/fulfilled. The academic/bibliographical references provided in this paper have been obtained from ISI web of knowledge, Scopus and Dialnet data bases, supporting the state of affairs on absorptive capacity and thereafter filtering by "Business Intelligence" and "Business Analytics". Specialized websites and Business Schools` Publications there have also been included, crowning the content on information management tools used that are currently used in the strategic consulting.Findings: Our contribution to the literature is the development of "smart absorptive capacity". This is a new capacity emerging from the reformulation of the classical concept of absorptive capacity wherein some aspects of its definition that might have been omitted are emphasized. The result of this new approach is the creation of a new Theoretical Model of Organizational Intelligence, which aims to explain, within the framework of the Resources and Capabilities Theory, the competitive advantage achieved by the so-called smart companies

  13. Aerosol absorption and radiative forcing

    Directory of Open Access Journals (Sweden)

    P. Stier


    Full Text Available We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006 significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA radiative forcing clear-sky from –0.79 to –0.53 W m−2 (33% and all-sky from –0.47 to –0.13 W m−2 (72%. Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36% clear-sky and of 0.12 W m−2 (92% all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W

  14. Differences in thermal optical response between intact diabetic and nondiabetic human skin (United States)

    Yeh, Shu-Jen; Hanna, Charles F.; Kantor, Stan; Hohs, Ronald; Khalil, Omar S.


    We observed a difference in the thermal response of localized reflectance signal of human skin between type-2 diabetic and non-diabetic volunteers. We investigated the use of this thermo-optical behavior as a basis for a non-invasive method for the determination of the diabetic status of a subject. We used a two-site temperature differential method, which is predicated upon the measurement of localized reflectance from two areas on the surface of the skin, each of these areas is subjected to a different thermal perturbation. The response of skin localized reflectance to temperature was measured and used in a classification algorithm. We used a discriminant function to classify subjects as diabetics or non-diabetics. In a prediction set of 24 non-invasive tests collected from 6 diabetics and 6 non-diabetics, the sensitivity ranged between 73% and 100%, and the specificity ranged between 75% and 100%, depending on the thermal conditions and probe-skin contact time. The difference in thermo-optical response of the skin of the two groups may be explained in terms of difference in response of cutaneous microcirculation to temperature, which is manifested as a difference in the near infrared light absorption and scattering. Another factor is the difference in the temperature response of the scattering coefficient between the two groups, which may be caused by cutaneous structural differences induced by non-enzymatic glycation of skin protein fibers, and/or by the difference in blood cell aggregation.

  15. Influence of anatomical site and topical formulation on skin penetration of sunscreens. (United States)

    Benson, Heather Ae; Sarveiya, Vikram; Risk, Stacey; Roberts, Michael S


    Sunscreen products are widely used to protect the skin from sun-related damage. Previous studies have shown that some sunscreen chemicals are absorbed across the skin to the systemic circulation. The current study shows that absorption into the skin of sunscreen chemicals applied to the face is up to four times greater than that of the same product applied to the back. This has implications for the way sunscreen products are formulated and may allow the use of less potent products on the face compared with the rest of the body. The effect of formulation vehicles on the release and skin penetration of the common sunscreen agent benzophenone-3 (common name oxybenzone) was also assessed. Penetration of benzophenone-3 across excised human epidermis and high-density polyethylene (HDPE) membrane was measured using in vitro Franz-type diffusion cells. Penetration and epidermal retention was measured following application of infinite and finite (epidermis only) doses of benzophenone-3 in five vehicles: liquid paraffin, coconut oil, 50:50 ethanol:coconut oil, aqueous cream BP, and oily cream BP. Highest benzophenone-3 skin retention was observed for the ethanol:coconut oil combination. Maximal and minimal benzophenone-3 fluxes were observed from liquid paraffin and coconut oil, respectively. The alcohol-based vehicle exhibited low benzophenone-3 release from the vehicle but high skin penetration and retention.

  16. Photoacoustic evaluation of the penetration of piroxicam gel applied with phonophoresis into human skin

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, F L F D; Barja, P R [Research and Development Institute, UNIVAP, Av. Shishima Hifumi 2911, Sao Jose dos Campos, SP, 12209-010 (Brazil); Acosta-Avalos, D, E-mail: barja@univap.b [Centro Brasileiro de Pesquisas Fisicas (CBPF), R.Xavier Sigaud 150, Rio de Janeiro, RJ, 22290-180 (Brazil)


    The photoacoustic (PA) technique has been increasingly employed in biomedical studies, allowing in vivo skin measurements not easily performed with other techniques. It is possible to use PA measurements to evaluate transdermal delivery of products topically applied through manual massage or phonophoresis, that is the utilization of ultrasound waves to enhance drug absorption. The aim of this study was to analyze the influence of the period of phonophoresis application in the transdermal penetration of piroxicam gel. In vivo PA measurements employed a tungsten lamp as light source and a thin aluminum foil closing the PA chamber. The PA signals of the arm (i) clean; and (ii) after phonophoresis were utilized to estimate the concentration of piroxicam into skin. For all (4) volunteers, drug concentration in skin after phonophoresis application was the same for the different application times employed; in this way, phonophoresis for one minute seemed to be sufficient to enhance piroxicam penetration into skin. The actual amount of drug delivered into tissue depends on the person, suggesting a dependency with the skin type, which affects the PA signal level [2]. We conclude that drug delivery depends not only on the application method, but also on the specific skin type.

  17. A strategy for skin irritation testing. (United States)

    Robinson, Michael K; Perkins, Mary A


    Skin irritation safety testing and risk assessment for new products, and the ingredients they contain, is a critical requirement before market introduction. In the past, much of this skin testing required the use of experimental animals. However, new current best approaches for skin corrosion and skin irritation testing and risk assessment are being defined, obviating the need for animal test methods. Several in vitro skin corrosion test methods have been endorsed after successful validation and are gaining acceptance by regulatory authorities. In vitro test methods for acute, cumulative (repeat exposure), and chronic (prolonged exposure) skin irritation are under development. Though not yet validated, many are being used successfully for testing and risk assessment purposes as documented through an expanding literature. Likewise, a novel acute irritation patch test in human subjects is providing a valid and ethical alternative to animal testing for prediction of chemical skin irritation potential. An array of other human test methods also have been developed and used for the prediction of cumulative/chronic skin irritation and the general skin compatibility of finished products. The development of instrumental methods (e.g., transepidermal water loss, capacitance, and so on) has provided the means for analyzing various biophysical properties of human skin and changes in these properties caused by exposure to irritants. However, these methods do not directly measure skin inflammation. A recently introduced skin surface tape sampling procedure has been shown to detect changes in skin surface cytokine recovery that correlate with inflammatory skin changes associated with chemical irritant exposures or existing dermatitis. It holds promise for more objective quantification of skin irritation events, including subclinical (sensory) irritation, in the future.

  18. Computed effects of sweat gland ducts on the propagation of 94 GHz waves in skin (United States)

    Shafirstein, Gal; Moros, Eduardo G.


    The effects of sweat gland ducts (SGD) on specific absorption rate and temperatures during millimeter wave irradiation of skin were investigated with a high resolution finite differences time domain model consisting of a 30 μm stratum corneum (SC), a 350 μm epidermis, 1000 μm dermis and five SGD (60 μm radius, 300 μm height, 370 μm separation). The source was a WR-10 waveguide irradiating at 94 GHz. Without SGD, specific absorption rate (SAR) and temperature maximum were in the dermis near epidermis. With SGD, a higher SAR maximum was inside SGD in the epidermis while temperature maximum moved to the epidermis/stratumcorneum junction. SGD significantly affected how GHz waves were absorbed in the skin. Implications of these finding in nociceptive research will be discussed as well as other potential medical applications.

  19. High temperature skin friction measurement (United States)

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


    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.

  20. The percutaneous permeation of a combination of 0.1% octenidine dihydrochloride and 2% 2-phenoxyethanol (octenisept® through skin of different species in vitro

    Directory of Open Access Journals (Sweden)

    Kietzmann Manfred


    Full Text Available Abstract Background A water based combination of 0.1% octenidine dihydrochloride and 2% 2 - phenoxyethanol is registered in many European countries as an antiseptic solution (octenisept® for topical treatment with high antimicrobial activity for human use, but octenidine based products have not been registered for veterinary use yet. The aim of the present study was to investigate whether octenidine dihydrochloride or 2 -phenoxyethanol, the two main components of this disinfectant, permeate through animal skin in vitro. Therefore, permeation studies were conducted using Franz-type diffusion cells. 2 ml of the test compound were applied onto 1.77 cm2 split skin of cats, dogs, cows and horses. To simulate wounded skin, cattle skin was treated with adhesive tapes 100 times, as well. Up to an incubation time of 28 hours samples of the acceptor chamber were taken and were analysed by UV-HPLC. Using the method of the external standard, the apparent permeability coefficient, the flux Jmax, and the recovery were calculated. Furthermore, the residues of both components in the skin samples were determined after completion of the diffusion experiment. Results After 28 hours no octenidine dihydrochloride was found in the receptor chamber of intact skin samples, while 2.7% of the topical applied octenidine dihydrochloride permeated through barrier disrupted cattle skin. 2 - phenoxyethanol permeated through all skin samples with the highest permeability in equine, followed by bovine, canine to feline skin. Furthermore, both components were found in the stratum corneum and the dermis of all split skin samples with different amounts in the examined species. Conclusion For 2-phenoxyethanol the systemic impact of the high absorption rate and a potential toxicological risk have to be investigated in further studies. Due to its low absorption rates through the skin, octenidine dihydrochloride is suitable for superficial skin treatment in the examined species.

  1. Skin melanocytes: biology and development


    Cichorek, Mirosława; Wachulska, Małgorzata; Stasiewicz, Aneta; Tymińska, Agata


    In the human skin, melanocytes are present in the epidermis and hair follicles. The basic features of these cells are the ability to melanin production and the origin from neural crest cells. This last element is important because there are other cells able to produce melanin but of different embryonic origin (pigmented epithelium of retina, some neurons, adipocytes). The life cycle of melanocyte consists of several steps including differentiation of melanocyte lineage/s from neural crest, mi...

  2. Gene therapy for skin diseases. (United States)

    Gorell, Emily; Nguyen, Ngon; Lane, Alfred; Siprashvili, Zurab


    The skin possesses qualities that make it desirable for gene therapy, and studies have focused on gene therapy for multiple cutaneous diseases. Gene therapy uses a vector to introduce genetic material into cells to alter gene expression, negating a pathological process. This can be accomplished with a variety of viral vectors or nonviral administrations. Although results are promising, there are several potential pitfalls that must be addressed to improve the safety profile to make gene therapy widely available clinically.

  3. Gene Therapy for Skin Diseases



    The skin possesses qualities that make it desirable for gene therapy, and studies have focused on gene therapy for multiple cutaneous diseases. Gene therapy uses a vector to introduce genetic material into cells to alter gene expression, negating a pathological process. This can be accomplished with a variety of viral vectors or nonviral administrations. Although results are promising, there are several potential pitfalls that must be addressed to improve the safety profile to make gene thera...

  4. Diabetes mellitus and the skin* (United States)

    Mendes, Adriana Lucia; Miot, Helio Amante; Haddad Junior, Vidal


    Several dermatoses are routinely associated with diabetes mellitus, especially in patients with chronic disease. This relationship can be easily proven in some skin disorders, but it is not so clear in others. Dermatoses such necrobiosis lipoidica, granuloma annulare, acanthosis nigricans and others are discussed in this text, with an emphasis on proven link with the diabetes or not, disease identification and treatment strategy used to control those dermatoses and diabetes. PMID:28225950

  5. Study of the vitamins A, E and C esters penetration into the skin by confocal Raman spectroscopy in vivo (United States)

    Mogilevych, Borys; Isensee, Debora; Rangel, Joao L.; Dal Pizzol, Carine; Martinello, Valeska C. A.; Dieamant, Gustavo C.; Martin, Airton A.


    Vitamins A, E and C play important role in skin homeostasis and protection. Hence, they are extensively used in many cosmetic and cosmeceutic products. However, their molecules are unstable, and do not easily penetrate into the skin, which drastically decreases its efficiency in topical formulations. Liposoluble derivative of the vitamin A - retinyl palmitate, vitamin E - tocopheryl acetate, and vitamin C - tetraisopalmitoyl ascorbic acid, are more stable, and are frequently used as an active ingredient in cosmetic products. Moreover, increased hydrophobicity of these molecules could lead to a higher skin penetration. The aim of this work is to track and compare the absorption of the liposoluble derivatives of the vitamins and their encapsulated form, into the healthy human skin in vivo. We used Confocal Raman Spectroscopy (CRS) that is proven to be helpful in label-free non-destructive investigation of the biochemical composition and molecular conformational analysis of the biological samples. The measurements were performed in the volar forearm of the 10 healthy volunteers. Skin was treated with both products, and Raman spectra were obtained after 15 min, 3 hours, and 6 hours after applying the formulation. 3510 Skin Composition Analyzer (River Diagnostics, The Netherlands) with 785 nm laser excitation was used to acquire information in the fingerprint region. Significant difference in permeation of the products was observed. Whereas only free form of retinyl palmitate penetrate the skin within first 15 minutes, all three vitamin derivatives were present under the skin surface in case of nanoparticulated form.

  6. You are what you eat: within-subject increases in fruit and vegetable consumption confer beneficial skin-color changes.

    Directory of Open Access Journals (Sweden)

    Ross D Whitehead

    Full Text Available BACKGROUND: Fruit and vegetable consumption and ingestion of carotenoids have been found to be associated with human skin-color (yellowness in a recent cross-sectional study. This carotenoid-based coloration contributes beneficially to the appearance of health in humans and is held to be a sexually selected cue of condition in other species. METHODOLOGY AND PRINCIPAL FINDINGS: Here we investigate the effects of fruit and vegetable consumption on skin-color longitudinally to determine the magnitude and duration of diet change required to change skin-color perceptibly. Diet and skin-color were recorded at baseline and after three and six weeks, in a group of 35 individuals who were without makeup, self-tanning agents and/or recent intensive UV exposure. Six-week changes in fruit and vegetable consumption were significantly correlated with changes in skin redness and yellowness over this period, and diet-linked skin reflectance changes were significantly associated with the spectral absorption of carotenoids and not melanin. We also used psychophysical methods to investigate the minimum color change required to confer perceptibly healthier and more attractive skin-coloration. Modest dietary changes are required to enhance apparent health (2.91 portions per day and attractiveness (3.30 portions. CONCLUSIONS: Increased fruit and vegetable consumption confers measurable and perceptibly beneficial effects on Caucasian skin appearance within six weeks. This effect could potentially be used as a motivational tool in dietary intervention.

  7. The isolated perfused human skin flap model: A missing link in skin penetration studies?


    Ternullo, Selenia; de Weerd, Louis; Flaten, Gøril Eide; Holsæter, Ann Mari; Skalko-Basnet, Natasa


    Development of effective (trans)dermal drug delivery systems requires reliable skinmodels to evaluate skin drug penetration. The isolated perfused human skin flap remainsmetabolically active tissue for up to 6 h during in vitro perfusion. We introduce the isolated perfused human skin flap as a close-to-in vivo skin penetration model. To validate the model's ability to evaluate skin drug penetration the solutions of a hydrophilic (calcein) and a lipophilic (rhodamine) fluorescence ...

  8. [E-health: the Skin House]. (United States)

    Hennekam, Michèle; Totté, Joan E E; Pasmans, Suzanne G M A


    The Dutch Skin House ( is an innovative and interactive online platform for patients with skin conditions and others involved, including health care professionals. Currently the platform is primarily aimed at skin disease in children and adolescents. It offers reliable and specialist information about everything from diagnosis to treatment. Patients can also create their own online protected, personal health record in which they can start a diagnostic or treatment plan. The aim of the Skin House is to create transmural continuation of care which is centred upon the patient. Additionally, the Skin House is focusing on scientific research by means of fellow platform the Research House.

  9. Ceramides and barrier function in healthy skin

    DEFF Research Database (Denmark)

    Jungerstedt, J; Hellgren, Lars; Drachmann, Tue;


    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups...... and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically...

  10. Skin cancer in patients with psoriasis

    DEFF Research Database (Denmark)

    Egeberg, A; Thyssen, J P; Gislason, G H


    BACKGROUND: Psoriasis is a chronic inflammatory skin disease that is commonly treated with ultraviolet phototherapy and systemic immunosuppressant drugs, which may confer a risk of skin cancer. Previous studies on the risk of skin cancer in patients with psoriasis have shown conflicting results....... OBJECTIVES: We investigated the risk of new-onset melanoma and non-melanoma skin cancer (NMSC), respectively, in a large cohort of patients with psoriasis and psoriatic arthritis. METHODS: Data on all Danish individuals aged ≥18 years between 1 January 1997 and 31 December 2012 were linked at individual...... of skin cancer is only modestly increased in patients with psoriasis, clinicians should remain vigilant....

  11. Quantification of thermal damage in skin tissue

    Institute of Scientific and Technical Information of China (English)

    Xu Feng; Wen Ting; Lu Tianjian; Seffen Keith


    Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great problem for burn patients. Thus, it is of great importance to quantify the thermal damage in skin tissue. In this paper, the available models and experimental methods for quantification of thermal damage in skin tissue are discussed.

  12. Skin immune sentinels in health and disease. (United States)

    Nestle, Frank O; Di Meglio, Paola; Qin, Jian-Zhong; Nickoloff, Brian J


    Human skin and its immune cells provide essential protection of the human body from injury and infection. Recent studies reinforce the importance of keratinocytes as sensors of danger through alert systems such as the inflammasome. In addition, newly identified CD103(+) dendritic cells are strategically positioned for cross-presentation of skin-tropic pathogens and accumulating data highlight a key role of tissue-resident rather than circulating T cells in skin homeostasis and pathology. This Review focuses on recent progress in dissecting the functional role of skin immune cells in skin disease.

  13. Mechanisms regulating skin immunity and inflammation. (United States)

    Pasparakis, Manolis; Haase, Ingo; Nestle, Frank O


    Immune responses in the skin are important for host defence against pathogenic microorganisms. However, dysregulated immune reactions can cause chronic inflammatory skin diseases. Extensive crosstalk between the different cellular and microbial components of the skin regulates local immune responses to ensure efficient host defence, to maintain and restore homeostasis, and to prevent chronic disease. In this Review, we discuss recent findings that highlight the complex regulatory networks that control skin immunity, and we provide new paradigms for the mechanisms that regulate skin immune responses in host defence and in chronic inflammation.

  14. Border preserving skin lesion segmentation (United States)

    Kamali, Mostafa; Samei, Golnoosh


    Melanoma is a fatal cancer with a growing incident rate. However it could be cured if diagnosed in early stages. The first step in detecting melanoma is the separation of skin lesion from healthy skin. There are particular features associated with a malignant lesion whose successful detection relies upon accurately extracted borders. We propose a two step approach. First, we apply K-means clustering method (to 3D RGB space) that extracts relatively accurate borders. In the second step we perform an extra refining step for detecting the fading area around some lesions as accurately as possible. Our method has a number of novelties. Firstly as the clustering method is directly applied to the 3D color space, we do not overlook the dependencies between different color channels. In addition, it is capable of extracting fine lesion borders up to pixel level in spite of the difficulties associated with fading areas around the lesion. Performing clustering in different color spaces reveals that 3D RGB color space is preferred. The application of the proposed algorithm to an extensive data-base of skin lesions shows that its performance is superior to that of existing methods both in terms of accuracy and computational complexity.

  15. Neutron Skins and Halo Orbits

    CERN Document Server

    Bonnard, J; Zuker, A P


    The strong dependence of Coulomb energies on nuclear radii makes it possible to extract the latter from calculations of the former. The resulting estimates of neutron skins indicate that two mechanisms are involved. The first one---isovector monopole polarizability---amounts to noting that when a particle is added to a system it drives the radii of neutrons and protons in different directions, tending to equalize the radii of both fluids independently of the neutron excess. This mechanism is well understood and the Duflo-Zuker (small) neutron skin values derived 14 years ago are consistent with recent measures and estimates. The alternative mechanism involves halo orbits whose huge sizes tend to make the neutron skins larger and have a subtle influence on the radial behavior of $sd$ and $pf$ shell nuclei. In particular, they account for the sudden rise in the isotope shifts of nuclei beyond $N=28$ and the near constancy of radii in the $A=40-56$ region. This mechanism, detected here for the first time, is not...

  16. Spectrum of pediatric skin biopsies

    Directory of Open Access Journals (Sweden)

    Grace D′costa


    Full Text Available Background: Skin diseases are common in childhood and they are common reasons for pediatric visits to the hospital. In spite of this high occurrence, there are very few prospective studies addressing this issue. Aims: The present study was directed at determining the spectrum of dermato-pathological lesions encountered in a large general tertiary care hospital, over a two-year period. Materials and Methods: 107 cases formed the total sample studied, in a part prospective and part retrospective study. A detailed clinical history was recorded on a proforma prepared for the purpose and gross photographs were taken wherever possible. Results: Skin biopsies accounted for 7.29% of the total surgical pathology load, 55.44% of the total pediatric biopsies and 10.82% of the total number of skin biopsies. The age and sex distribution pattern revealed that the maximum number of biopsies (62.61% were of older children, with a male preponderance (57.94%. The anatomic distribution pattern indicated predominant involvement of the limbs (59.82%. The maximum numbers of cases were of infectious nature (24.29%; the most frequently encountered being borderline tuberculoid Hansen′s disease (8.4%. A positive correlation with the clinical diagnosis was obtained in 56.07% cases. Conclusions: Histopathology contributed to the diagnosis in a significant number of (82.23% cases, indicating its importance and utility.

  17. Human papillomaviruses and skin cancer. (United States)

    Smola, Sigrun


    Human papillomaviruses (HPVs) infect squamous epithelia and can induce hyperproliferative lesions. More than 120 different HPV types have been characterized and classified into five different genera. While mucosal high-risk HPVs have a well-established causal role in anogenital carcinogenesis, the biology of cutaneous HPVs is less well understood. The clinical relevance of genus beta-PV infection has clearly been demonstrated in patients suffering from epidermodysplasia verruciformis (EV), a rare inherited disease associated with ahigh rate of skin cancer. In the normal population genus beta-PV are suspected to have an etiologic role in skin carcinogenesis as well but this is still controversially discussed. Their oncogenic potency has been investigated in mouse models and in vitro. In 2009, the International Agency for Research on Cancer (IARC) classified the genus beta HPV types 5 and 8 as "possible carcinogenic" biological agents (group 2B) in EV disease. This chapter will give an overview on the knowns and unknowns of infections with genus beta-PV and discuss their potential impact on skin carcinogenesis in the general population.

  18. Permeation of tecnazene through human skin in vitro as assessed by HS-SPME and GC-MS. (United States)

    Bhatt, Varsha D; Soman, Rajiv S; Miller, Matthew A; Kasting, Gerald B


    Permeation of tecnazene into and through human cadaver skin in vitro was assessed using a CC-MS method employing HS-SPME for receptor solution analyses. Two doses of tecnazene dissolved in acetone, corresponding to 103 and 864 microg/cm2 of tecnazene, were applied to skin mounted on Franz diffusion cells and placed in a fume hood. Cells were either occluded with aluminum foil or left unoccluded. Total absorption of tecnazene (dermis + receptor fluid) after 48 h was 2.2-6.1% of the applied dose for the unoccluded treatments and 22-33% for the occluded treatments. Potentially absorbed dose including all tecnazene that may have eventually permeated the skin ranged from 10% unoccluded to 42-53% occluded. Accumulation in the receptor solutions was satisfactorily described by a working diffusion model after upward adjustment of the partition coefficient for tecnazene in all skin layers by a factor of 5-16 versus a priori values. However, residual amounts of tecnazene in both the epidermis and dermis were higher than those estimated from the model, suggesting the existence of tissue binding not accounted for in the calculation. The results indicate that the diffusion model as presently calibrated may significantly underestimate both systemic absorption and skin concentrations of highly lipophilic compounds, as predicted from data generated from in vitro skin permeation assays. Model predictions could be improved by better accounting for partitioning into the epidermis and dermis.

  19. Evaluation of the intake of radon through skin from thermal water. (United States)

    Sakoda, Akihiro; Ishimori, Yuu; Tschiersch, Jochen


    The biokinetics of radon in the body has previously been studied with the assumption that its absorption through the skin is negligibly small. This assumption would be acceptable except in specific situations, such as bathing in a radon hot spring where the radon concentration in thermal water is far higher than that in air. The present study focused on such a situation in order to better understand the biokinetics of radon. To mathematically express the entry of radon through the skin into the body, we first modified the latest sophisticated biokinetic model for noble gases. Values of an important parameter for the model-the skin permeability coefficient K (m s(-1))-were derived using data from previous human studies. The analysis of such empirical data, which corresponded to radon concentrations in the air exhaled by subjects during and following bathing in radon-rich thermal water, revealed that the estimated K values had a log-normal distribution. The validity of the K values and the characteristics of the present model are then discussed. Furthermore, the impact of the intake of radon or its progeny via inhalation or skin absorption on radiation dose was also assessed for possible exposure scenarios in a radon hot spring. It was concluded that, depending on the radon concentration in thermal water, there might be situations in which the dose contribution resulting from skin absorption of radon is comparable to that resulting from inhalation of radon and its progeny. This conclusion can also apply to other therapeutic situations (e.g. staying in the pool for a longer period).

  20. Evaluation of the intake of radon through skin from thermal water (United States)

    Sakoda, Akihiro; Ishimori, Yuu; Tschiersch, Jochen


    The biokinetics of radon in the body has previously been studied with the assumption that its absorption through the skin is negligibly small. This assumption would be acceptable except in specific situations, such as bathing in a radon hot spring where the radon concentration in thermal water is far higher than that in air. The present study focused on such a situation in order to better understand the biokinetics of radon. To mathematically express the entry of radon through the skin into the body, we first modified the latest sophisticated biokinetic model for noble gases. Values of an important parameter for the model—the skin permeability coefficient K (m s−1)—were derived using data from previous human studies. The analysis of such empirical data, which corresponded to radon concentrations in the air exhaled by subjects during and following bathing in radon-rich thermal water, revealed that the estimated K values had a log-normal distribution. The validity of the K values and the characteristics of the present model are then discussed. Furthermore, the impact of the intake of radon or its progeny via inhalation or skin absorption on radiation dose was also assessed for possible exposure scenarios in a radon hot spring. It was concluded that, depending on the radon concentration in thermal water, there might be situations in which the dose contribution resulting from skin absorption of radon is comparable to that resulting from inhalation of radon and its progeny. This conclusion can also apply to other therapeutic situations (e.g. staying in the pool for a longer period). PMID:26983980

  1. The optical properties and spectral features of malignant skin melanocytes in the terahertz frequency range (United States)

    Goryachuk, A. A.; Begaeva, V. A.; Khodzitsky, M. K.; Truloff, A. S.


    The samples of cells of mice's melanocytes have been investigated. Their optical properties and spectral features were investigated by terahertz time-domain spectroscopy (TDS) in transmission mode. It was found that the optical properties of oncological melanocytes and normal cells are different and oncological cells have spectral features of absorption coefficient so it can be concluded that it is easy to discriminate mice's oncological skin melanocytes by using THz TDS.

  2. Near real-time skin deformation mapping (United States)

    Kacenjar, Steve; Chen, Suzie; Jafri, Madiha; Wall, Brian; Pedersen, Richard; Bezozo, Richard


    A novel in vivo approach is described that provides large area mapping of the mechanical properties of the skin in human patients. Such information is important in the understanding of skin health, cosmetic surgery[1], aging, and impacts of sun exposure. Currently, several methods have been developed to estimate the local biomechanical properties of the skin, including the use of a physical biopsy of local areas of the skin (in vitro methods) [2, 3, and 4], and also the use of non-invasive methods (in vivo) [5, 6, and 7]. All such methods examine localized areas of the skin. Our approach examines the local elastic properties via the generation of field displacement maps of the skin created using time-sequence imaging [9] with 2D digital imaging correlation (DIC) [10]. In this approach, large areas of the skin are reviewed rapidly, and skin displacement maps are generated showing the contour maps of skin deformation. These maps are then used to precisely register skin images for purposes of diagnostic comparison. This paper reports on our mapping and registration approach, and demonstrates its ability to accurately measure the skin deformation through a described nulling interpolation process. The result of local translational DIC alignment is compared using this interpolation process. The effectiveness of the approach is reported in terms of residual RMS, image entropy measures, and differential segmented regional errors.


    Directory of Open Access Journals (Sweden)



    Full Text Available Aging is a continuous, dynamic, and an irreversible process. Direct exposure to ultra-violet radiations, skin is particularly prone to early aging, known as photo aging. Skin aging is particularly important because of its visibility and social impact. As women age we will notice changes to our skin and hair during the menopause. Dry, thinning, fragile, less tolerant and sagging skin are common complaints. The main reasons for the change in skin is the loss of estrogen, testosterone and dehydroepiandrosterone (DHEA etc, 1, 2, 3 from the age of 35 onwards up to menopause, the more we have had long-term exposure to the elements, such as sun and wind the more this becomes evident. Estrogen is very involved in the normal function of the skin. It directly affects the function of key cells in the skin, like the fibroblast (produces collagen and elastin, keratinocyte (closely involved in skin protection and melanocytes (involved in evenness of skin color, etc.. It also helps regulate hair follicle function (hair production as well as sebaceous gland activity (producing skin oils. After the age of forty most of women enters menopause, during which estrogens levels decreases, which leads to different types of hair and skin changes which has been described in this article.

  4. Developing Skin Analogues for a Robotic Octopus

    Institute of Scientific and Technical Information of China (English)

    Jinping Hou; Richard H.C.Bonser; George Jeronimidis


    In order to fabricate a biomimetic skin for an octopus inspired robot,a new process was developed based on mechanical properties measured from real octopus skin.Various knitted nylon textiles were tested and the one of 10-denier nylon was chosen as reinforcement.A combination of Ecoflex 0030 and 0010 silicone rubbers was used as matrix of the composite to obtain the right stiffness for the skin-analogue system.The open mould fabrication process developed allows air bubble to escape easily and the artificial skin produced was thin and waterproof.Material properties of the biomimetic skin were characterised using static tensile and instrumented scissors cutting tests.The Young's moduli of the artificial skin are 0.08 MPa and 0.13 MPa in the longitudinal and transverse directions,which are much lower than those of the octopus skin.The strength and fracture toughness of the artificial skin,on the other hand are higher than those of real octopus skins.Conically-shaped skin prototypes to be used to cover the robotic arm unit were manufactured and tested.The biomimetic skin prototype was stiff enough to maintain it conical shape when filled with water.The driving force for elongation was reduced significantly compared with previous prototypes.

  5. Vehicle effects on in vitro transdermal absorption of sevoflurane in the bullfrog, Rana catesbeiana. (United States)

    Ardente, Amanda J; Barlow, Beth M; Burns, Patrick; Goldman, Rebecca; Baynes, Ronald E


    The experimental objectives were to identify a vehicle which produces a homogenous formulation when combined with the anesthetic solution sevoflurane and understand the dermal absorption of sevoflurane in silastic membranes and amphibian skin in vitro utilizing a flow-through diffusion system. Seven vehicles were evaluated in varying ratios with 5 formulations resulting in the desired homogenous consistency for practical application. Sevoflurane diffusion across silastic membranes was influenced by pluronic/lecithin organogel (PLO), pluronic F 127 20% gel, and sterile lube. Flux and permeability across silastic membranes were significantly greater in sterile lube than in the other formulations. While no significant vehicle effects were observed in bullfrog skin, the flux-time profiles suggest that sevoflurane diffusion in bullfrog skin may be positively influenced by PLO. Future in vivo studies are required to assess sevoflurane retention after removal of these formulations to more accurately control the plane of anesthesia in amphibians.

  6. In-vitro methods for testing dermal absorption and penetration of toxic gases. (United States)

    Gaskin, Sharyn; Pisaniello, Dino; Edwards, John W; Bromwich, David; Reed, Sue; Logan, Michael; Baxter, Christina


    This technical note provides details of an experimental technique for in-vitro skin studies with atmospheric chemical challenge. There appear to be major evidence gaps in relation to dermal exposure of gases. We describe a modification of standard OECD protocols for an atmospheric delivery system which can be used to understand interaction of toxic gases and the skin. The system can be used to examine the mechanisms by which skin uptake occurs. Auxiliary components which allow for parameter variation such as temperature and relative humidity are also described. Methodology presented in this technical note uses examples of gas challenges (ammonia, chlorine) to illustrate its application to gases of differing physicochemical properties. This adapted protocol can be applied in the context of HAZMAT scenarios involving atmospheric toxic chemical release and dermal absorption potential under variable exposure conditions.

  7. Predicting dermal absorption of gas-phase chemicals: transient model development, evaluation, and application

    DEFF Research Database (Denmark)

    Gong, M.; Zhang, Y.; Weschler, Charles J.


    for scenarios in which (A) a previously unexposed occupant encounters gas-phase phthalates in three different environments over a single 24-h period; (B) the same as 'A', but the pattern is repeated for seven consecutive days. In the 24-h scenario, the transient model predicts more phthalate absorbed into skin......A transient model is developed to predict dermal absorption of gas-phase chemicals via direct air-to-skin-to-blood transport under non-steady-state conditions. It differs from published models in that it considers convective mass-transfer resistance in the boundary layer of air adjacent to the skin...... and less absorbed into blood than would a steady-state model. In the 7-day scenario, results calculated by the transient and steady-state models converge over a time period that varies between 3 and 4days for all but the largest phthalate (DEHP). Dermal intake is comparable to or larger than inhalation...

  8. Percutaneous penetration through slightly damaged skin

    DEFF Research Database (Denmark)

    Nielsen, Jesper B


    Guidelines for experimental studies of percutaneous penetration prescribe optimal barrier integrity of the skin. The barrier integrity of the skin exposed in occupational or household situations is, however, not always ideal, and skin problems are among the most dominant reasons for absence from...... work. We have therefore evaluated an experimental model for percutaneous penetration through slightly damaged skin. The influence of a slight damage to the skin was evaluated using five pesticides covering a wide range of solubilities. We used an experimental model with static diffusion cells mounted...... with human skin. A slight damage to the barrier integrity was induced by pre-treatment of the skin with sodium lauryl sulphate (SLS) before pesticide exposure. The experimental model with 3 h pre-treatment with SLS (0.1% or 0.3%) assured a significant but controlled damage to the barrier integrity, a damage...

  9. Skin deposits in hereditary cystatin C amyloidosis

    DEFF Research Database (Denmark)

    Benedikz, Eirikur; Blöndal, H; Gudmundsson, G


    Clinically normal skin from 47 individuals aged 9-70 years was investigated. Cystatin C amyloid deposits were found in various locations of the skin by light and/or electron microscopy, in all 12 patients with a clinical history of hereditary cystatin C amyloidosis (HCCA). Six asymptomatic...... individuals, who had the Alu 1 restriction fragment length polymorphism (RFLP) marker reported to cosegregate with the disease, also had cystatin C amyloid deposits in the skin. Three asymptomatic individuals (age 17-46) belonging to the HCCA families were without amyloid in the skin but had Alu 1 RFLP marker....... Skin from 12 individuals who served as controls and skin from 14 close relatives of the patients was negative for amyloid. Punch biopsy of the skin is a simple procedure which is of value for the diagnosis of HCCA, even before the appearance of clinical symptoms. This method might also be of use...

  10. Ceramides and barrier function in healthy skin

    DEFF Research Database (Denmark)

    Mutanu Jungersted, Jakob; Hellgren, Lars; Høgh, Julie Kaae


    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups...... and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically...... significant differences were found between young and old skin for ceramide subgroups or ceramide/cholesterol ratios, and there was no statistically significant correlation between answers about dry skin and ceramide levels. Interestingly, a statistically significant higher ceramide/cholesterol ratio was found...

  11. Ceramides and barrier function in healthy skin. (United States)

    Mutanu Jungersted, Jakob; Hellgren, Lars I; Høgh, Julie K; Drachmann, T; Jemec, Gregor B E; Agner, Tove


    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically significant differences were found between young and old skin for ceramide subgroups or ceramide/cholesterol ratios, and there was no statistically significant correlation between answers about dry skin and ceramide levels. Interestingly, a statistically significant higher ceramide/cholesterol ratio was found for men than for women (p = 0.02).

  12. Friction and durability of virgin and damaged skin with and without skin cream treatment using atomic force microscopy


    Bharat Bhushan; Si Chen; Shirong Ge


    Skin can be damaged by the environment easily. Skin cream is an effective and rapid way to moisten the skin by changing the skin surface properties. Rat skin and pig skin are common animal models for studies and were used as skin samples in this study. The nano- and macroscale friction and durability of damaged skin were measured and compared with those of virgin (intact/undamaged) skin. The effect of skin cream on friction and durability of damaged and virgin skin samples is discussed. The e...

  13. Silver-resistance, allergy, and blue skin: truth or urban legend? (United States)

    Sterling, Jose P


    Medical and non-medical uses of silver are increasing. While the health benefits of silver therapy are widely claimed, few studies address the possible side effects of resistance, allergy, or skin discoloration. In this manuscript, a review of silver absorption, mechanism of action, allergy, microbial resistance and skin changes is presented. The ideal silver-delivery system is unknown. Most studies of side effects are animal or laboratory studies, which may not correlate with human experience. There is little correlation between serum silver levels, end-organ deposition and cytotoxic effects. The multiple mechanisms of antimicrobial action make true resistance unlikely. In microbes, genotypic resistance does not necessarily confer phenotypic resistance. Most cases of argyria occur from occupational exposure or from ingestion of colloidal silver rather than from topical application. Although toxicity, resistance and chronic skin changes are a theoretic concern, the lack of reported side effects despite widespread silver use is reassuring.

  14. Evaluation of Barrier Skin Cream Effectiveness Against JP-8 Jet Fuel Absorption and Irritation (United States)


    trichromatic color matching of spectral lights, which is a function of their wavelengths from 380 to 780 nm ( Broadbent , 2004). METHODS...sufficient protection provided by candidate barrier creams in the animal model. REFERENCES Broadbent , A. D. "A critical review of the

  15. Development of In Vitro Isolated Perfused Porcine Skin Flaps for Study of Percutaneous Absorption of Xenobiotics (United States)


    single pedicle, axial pattern tubed flaps (Figure 1). In the stage 1 procedure, each female pig was premedicated with atropine sulfate (0.04 mg/kg IM...R.H., and Hadgraft, J. (1985). Pharmacokinetic interpretation of the plasma levels of clonidine following transdermal delivery. J. Pharm. Sci. 74...Pigs weighing 18 to 32 kg are premedicated with atropine sulfate (0.04 mg/kg I .m.) and xylazine hydrochloridee (0.2 mg/kg i.m.). Anesthesia is

  16. Development of In Vitro Isolated Perfused Porcine Skin Flaps for Study of Percutaneous Absorption of Xenobiotics (United States)


    itopiedo the vene comitantes iswhied ponsibe),andi prian eril, sred to the surte rgn prounding tupbred fla p sa.s fl wn a u othcadlsuperficial ei ti artery...and its pare tevenae comitantesis raised ponsbl) wandn prianfri~, sred to the ssltergnprroundiong tubedafapt shreseus.oio~nnlto *.11 a single-pedicle

  17. Sound absorption property of openpore aluminum foams

    Directory of Open Access Journals (Sweden)

    WANG Fang


    Full Text Available This paper presents a study on sound absorption property of aluminum foam by evaluating its sound absorption coefficients using standing wave tube method. Experimental results showed that the average values of sound absorption coefficients (over the test frequency range are all above 0.4, which indicate very good sound absorption property of the aluminum foams. The sound absorption coefficient is affected by frequency and pore structure, and reaches its maximum value at around 1 000 Hz. With the increase of porosity and decrease of cell diameter, the sound absorption coefficient values increase.

  18. Physicochemical determinants of linear alkylbenzene sulfonate (LAS) disposition in skin exposed to aqueous cutting fluid mixtures. (United States)

    Baynes, Ronald E; Brooks, James D; Barlow, Beth M; Riviere, Jim E


    Linear alkylbenzene sulfonate (LAS) is added to cutting fluid formulations to enhance the performance of metal machining operations, but this surfactant can cause contact dermatitis in workers involved in these operations. The purpose of this study was to determine how cutting fluid additives influence dermal disposition of 14C-LAS in mineral oil- or polyethylene glycol 200 (PEG)-based mixtures when topically applied to silastic membranes and porcine skin in an in vitro flow-through diffusion cell system. 14C-LAS mixtures were formulated with three commonly used cutting fluid additives; 0 or 2% triazine (TRI), 0 or 5% triethanolamine (TEA), and 0 or 5% sulfurized ricinoleic acid (SRA). LAS absorption was limited to less than a 0.5% dose and the additives in various combinations influenced the physicochemical characteristics of the dosing mixture. LAS was more likely to partition into the stratum corneum (SC) in mineral oil mixtures, and LAS absorption was significantly greater in the complete mixture. TRI enhanced LAS transport, and the presence of SRA decreased LAS critical micelle concentration (CMC) which reduced LAS monomers available for transport. TEA increased mixture viscosity, and this may have negated the apparent enhancing properties of TRI in several mixtures. In summary, physicochemical interactions in these mixtures influenced availability of LAS for absorption and distribution in skin, and could ultimately influence toxicological responses in skin.

  19. Fluorescence excitation-emission matrix spectroscopy of vitiligo skin in vivo (Conference Presentation) (United States)

    Zhao, Jianhua; Richer, Vincent; Al Jasser, Mohammed; Zandi, Soodabeh; Kollias, Nikiforos; Kalia, Sunil; Zeng, Haishan; Lui, Harvey


    Fluorescence signals depend on the intensity of the exciting light, the absorption properties of the constituent molecules, and the efficiency with which the absorbed photons are converted to fluorescence emission. The optical features and appearance of vitiligo have been explained primarily on the basis of reduced epidermal pigmentation, which results in abnormal white patches on the skin. The objective of this study is to explore the fluorescence properties of vitiligo and its adjacent normal skin using fluorescence excitation-emission matrix (EEM) spectroscopy. Thirty five (35) volunteers with vitiligo were acquired using a double-grating spectrofluorometer with excitation and emission wavelengths of 260-450 nm and 300-700 nm respectively. As expected, the most pronounced difference between the spectra obtained from vitiligo lesions compared to normally pigmented skin was that the overall fluorescence was much higher in vitiligo; these differences increased at shorter wavelengths, thus matching the characteristic spectral absorption of epidermal melanin. When comparing the fluorescence spectra from vitiligo to normal skin we detected three distinct spectral bands centered at 280nm, 310nm, and 335nm. The 280nm band may possibly be related to inflammation, whereas the 335 nm band may arise from collagen or keratin cross links. The source of the 310 nm band is uncertain; it is interesting to note its proximity to the 311 nm UV lamps used for vitiligo phototherapy. These differences are accounted for not only by changes in epidermal pigment content, but also by other optically active cutaneous biomolecules.

  20. Theory of graphene saturable absorption

    CERN Document Server

    Marini, A; de Abajo, F J Garcia


    Saturable absorption is a non-perturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a non-perturbative single-particle approach, describing conduction-electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics non-perturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. The results are in excellent agreement with atomistic quantum-mechanical simulations including high...

  1. Geometrical interpretation of optical absorption

    Energy Technology Data Exchange (ETDEWEB)

    Monzon, J. J.; Barriuso, A. G.; Sanchez-Soto, L. L. [Departamento de Optica, Facultad de Fisica, Universidad Complutense, E-28040 Madrid (Spain); Montesinos-Amilibia, J. M. [Departamento de Geometria y Topologia, Facultad de Matematicas, Universidad Complutense, E-28040 Madrid (Spain)


    We reinterpret the transfer matrix for an absorbing system in very simple geometrical terms. In appropriate variables, the system appears as performing a Lorentz transformation in a (1 + 3)-dimensional space. Using homogeneous coordinates, we map that action on the unit sphere, which is at the realm of the Klein model of hyperbolic geometry. The effects of absorption appear then as a loxodromic transformation, that is, a rhumb line crossing all the meridians at the same angle.

  2. Photodetector with enhanced light absorption (United States)

    Kane, James


    A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

  3. Practical absorption limits of MPP absorber

    Institute of Scientific and Technical Information of China (English)

    MAA Dah-You


    The construction and properties of microperforated panel (MPP) absorber are discussed. The absorption limit of the absorber had been shown that low values of the perforate constant k = d(f/10)1/2 and the orifice diameter d (in mm) are essential for MPP to have high absorption in wide frequency band. To find the exact limits, take 1 for k as a start, because both specific resistance and high absorption require k around one. And the orifice diameter d is chosen as 0.1 mm, so that the peak absorption coefficient (resonance absorption) is at 1000 Hz,and high sound frequency may be in the absorption region. Is it possible for a single layer of such an MPP to cover the whole absorption region required in practice? The half-absorption limit is not a good criterion, because low absorption comes in also in some cases. The 0.5 absorption coefficient limit is suggested for practical region, as a standard for comparison. Absorption curves were drawn for different load resistances, of absorption coefficients versus frequency.Ordinary MPP absorber absorbs in slightly over two octaves, and the new absorber with r = 1 (specific resistance equal to the characteristic impedance in air)is slightly better than these, 2.5 octaves. The new absorbers with r > 1, are much better than these, and some satisfies high absorption in broad frequency range. Realization of these will mean great progress of MPP absorbers.

  4. QED-driven laser absorption

    CERN Document Server

    Levy, M C; Ratan, N; Sadler, J; Ridgers, C P; Kasim, M; Ceurvorst, L; Holloway, J; Baring, M G; Bell, A R; Glenzer, S H; Gregori, G; Ilderton, A; Marklund, M; Tabak, M; Wilks, S C; Norreys, P A


    Absorption covers the physical processes which convert intense photon flux into energetic particles when a high-power laser illuminates optically-thick matter. It underpins important petawatt-scale applications today, e.g., medical-quality proton beam production. However, development of ultra-high-field applications has been hindered since no study so far has described absorption throughout the entire transition from the classical to the quantum electrodynamical (QED) regime of plasma physics. Here we present a model of absorption that holds over an unprecedented six orders-of-magnitude in optical intensity and lays the groundwork for QED applications of laser-driven particle beams. We demonstrate 58% efficient \\gamma-ray production at $1.8\\times 10^{25}~\\mathrm{W~ cm^{-2}}$ and the creation of an anti-matter source achieving $4\\times 10^{24}\\ \\mathrm{positrons}\\ \\mathrm{cm^{-3}}$, $10^{6}~\\times$ denser than of any known photonic scheme. These results will find applications in scaled laboratory probes of bla...

  5. The isolated perfused human skin flap model: A missing link in skin penetration studies? (United States)

    Ternullo, Selenia; de Weerd, Louis; Flaten, Gøril Eide; Holsæter, Ann Mari; Škalko-Basnet, Nataša


    Development of effective (trans)dermal drug delivery systems requires reliable skin models to evaluate skin drug penetration. The isolated perfused human skin flap remains metabolically active tissue for up to 6h during in vitro perfusion. We introduce the isolated perfused human skin flap as a close-to-in vivo skin penetration model. To validate the model's ability to evaluate skin drug penetration the solutions of a hydrophilic (calcein) and a lipophilic (rhodamine) fluorescence marker were applied. The skin flaps were perfused with modified Krebs-Henseleit buffer (pH7.4). Infrared technology was used to monitor perfusion and to select a well-perfused skin area for administration of the markers. Flap perfusion and physiological parameters were maintained constant during the 6h experiments and the amount of markers in the perfusate was determined. Calcein was detected in the perfusate, whereas rhodamine was not detectable. Confocal images of skin cross-sections shoved that calcein was uniformly distributed through the skin, whereas rhodamine accumulated in the stratum corneum. For comparison, the penetration of both markers was evaluated on ex vivo human skin, pig skin and cellophane membrane. The proposed perfused flap model enabled us to distinguish between the penetrations of the two markers and could be a promising close-to-in vivo tool in skin penetration studies and optimization of formulations destined for skin administration.

  6. Expert System For Diagnosis Of Skin Diseases

    Directory of Open Access Journals (Sweden)

    A.A.L.C. Amarathunga


    Full Text Available Abstract Dermatology is a one of major session of medicine that concerned with the diagnosis and treatment of skin diseases. Skin diseases are the most common form of disease in humans. Recently many of researchers have advocated and developed the imaging of human vision or in the loop approach to visual object recognition. This research paper presents a development of a skin diseases diagnosis system which allows user to identify diseases of the human skin and to provide advises or medical treatments in a very short time period. For this purpose user will have to upload an image of skin disease to our system and answer questions based on their skin condition or symptoms. It will be used to detect diseases of the skin and offer a treatment recommendation. This system uses technologies such as image processing and data mining for the diagnosis of the disease of the skin. The image of skin disease is taken and it must be subjected to various preprocessing for noise eliminating and enhancement of the image. This image is immediately segmentation of images using threshold values. Finally data mining techniques are used to identify the skin disease and to suggest medical treatments or advice for users. This expert system exhibits disease identification accuracy of 85 for Eczema 95 for Impetigo and 85 for Melanoma.

  7. Preparation of Inactivated Human Skin Using High Hydrostatic Pressurization for Full-Thickness Skin Reconstruction.

    Directory of Open Access Journals (Sweden)

    Pham Hieu Liem

    Full Text Available We have reported that high-hydrostatic-pressure (HHP technology is safe and useful for producing various kinds of decellularized tissue. However, the preparation of decellularized or inactivated skin using HHP has not been reported. The objective of this study was thus to prepare inactivated skin from human skin using HHP, and to explore the appropriate conditions of pressurization to inactivate skin that can be used for skin reconstruction. Human skin samples of 8 mm in diameter were packed in bags filled with normal saline solution (NSS or distilled water (DW, and then pressurized at 0, 100, 150, 200 and 1000 MPa for 10 minutes. The viability of skin after HHP was evaluated using WST-8 assay. Outgrowth cells from pressurized skin and the viability of pressurized skin after cultivation for 14 days were also evaluated. The pressurized skin was subjected to histological evaluation using hematoxylin and eosin staining, scanning electron microscopy (SEM, immunohistochemical staining of type IV collagen for the basement membrane of epidermis and capillaries, and immunohistochemical staining of von Willebrand factor (vWF for capillaries. Then, human cultured epidermis (CE was applied on the pressurized skin and implanted into the subcutis of nude mice; specimens were subsequently obtained 14 days after implantation. Skin samples pressurized at more than 200 MPa were inactivated in both NSS and DW. The basement membrane and capillaries remained intact in all groups according to histological and immunohistological evaluations, and collagen fibers showed no apparent damage by SEM. CE took on skin pressurized at 150 and 200 MPa after implantation, whereas it did not take on skin pressurized at 1000 MPa. These results indicate that human skin could be inactivated after pressurization at more than 200 MPa, but skin pressurized at 1000 MPa had some damage to the dermis that prevented the taking of CE. Therefore, pressurization at 200 MPa is optimal for

  8. Drug hypersensitivity reactions involving skin. (United States)

    Hausmann, Oliver; Schnyder, Benno; Pichler, Werner J


    Immune reactions to drugs can cause a variety of diseases involving the skin, liver, kidney, lungs, and other organs. Beside immediate, IgE-mediated reactions of varying degrees (urticaria to anaphylactic shock), many drug hypersensitivity reactions appear delayed, namely hours to days after starting drug treatment, showing a variety of clinical manifestations from solely skin involvement to fulminant systemic diseases which may be fatal. Immunohistochemical and functional studies of drug-specific T cells in patients with delayed reactions confirmed a predominant role for T cells in the onset and maintenance of immune-mediated delayed drug hypersensitivity reactions (type IV reactions). In these reactions, drug-specific CD4+ and CD8+ T cells are stimulated by drugs through their T cell receptors (TCR). Drugs can stimulate T cells in two ways: they can act as haptens and bind covalently to larger protein structures (hapten-carrier model), inducing a specific immune response. In addition, they may accidentally bind in a labile, noncovalent way to a particular TCR of the whole TCR repertoire and possibly also major histocompatibility complex (MHC)-molecules - similar to their pharmacologic action. This seems to be sufficient to reactivate certain, probably in vivo preactivated T cells, if an additional interaction of the drug-stimulated TCR with MHC molecules occurs. The mechanism was named pharmacological interaction of a drug with (immune) receptor and thus termed the p-i concept. This new concept may explain the frequent skin symptoms in drug hypersensitivity to oral or parenteral drugs. Furthermore, the various clinical manifestations of T cell-mediated drug hypersensitivity may be explained by distinct T cell functions leading to different clinical phenotypes. These data allowed a subclassification of the delayed hypersensitivity reactions (type IV) into T cell reactions which, by releasing certain cytokines and chemokines, preferentially activate and recruit

  9. In vivo photothermal optical coherence tomography for non-invasive imaging of endogenous absorption agents. (United States)

    Makita, Shuichi; Yasuno, Yoshiaki


    In vivo photothermal optical coherence tomography (OCT) is demonstrated for cross-sectional imaging of endogenous absorption agents. In order to compromise the sensitivity, imaging speed, and sample motion immunity, a new photothermal detection scheme and phase processing method are developed. Phase-resolved swept-source OCT and fiber-pigtailed laser diode (providing excitation at 406 nm) are combined to construct a high-sensitivity photothermal OCT system. OCT probe and excitation beam coaxially illuminate and are focused on tissues. The photothermal excitation and detection procedure is designed to obtain high efficiency of photothermal effect measurement. The principle and method of depth-resolved cross-sectional imaging of absorption agents with photothermal OCT has been derived. The phase-resolved thermal expansion detection algorithm without motion artifact enables in vivo detection of photothermal effect. Phantom imaging with a blood phantom and in vivo human skin imaging are conducted. A phantom with guinea-pig blood as absorber has been scanned by the photothermal OCT system to prove the concept of cross-sectional absorption agent imaging. An in vivo human skin measurement is also performed with endogenous absorption agents.

  10. Research on Skin Diseases - USSR - (United States)


    group 6, Today Tilth the introduction of mandatory accounting on form 25-v, wre have begun to enter information on the morbidity of the infantile ...34 population. Table 2 illustrates preliminary data on the morbidity of the infantile population in the first half of 1958 for Leningrad but does not...Skin cancer 0.01 16« Acute eczema 5.6 33. Non-malignant tumor 1.9 17. Chronic eczema 2.7 . 39, Other diseases .’. 2.0 18. Eczemotization

  11. Hair bleaching and skin burning. (United States)

    Forster, K; Lingitz, R; Prattes, G; Schneider, G; Sutter, S; Schintler, M; Trop, M


    Hairdressing-related burns are preventable and therefore each case is one too many. We report a unique case of a 16-yr-old girl who suffered full-thickness chemical and thermal burns to the nape of her neck and superficial burns to the occiput after her hair had been dyed blond and placed under a dryer to accelerate the highlighting procedure. The wound on the nape of the neck required surgical debridement and skin grafting. The grafted area resulted in subsequent scar formation.

  12. Resonant Optical Absorption in Semiconductor Quantum Wells

    Institute of Scientific and Technical Information of China (English)

    YU Li-Yuan; CAO Jun-Cheng


    @@ We have calculated the intraband photon absorption coefficients of hot two-dimensional electrons interacting with polar-optical phonon modes in quantum wells. The dependence of the photon absorption coefficients on the photon wavelength λ is obtained both by using the quantum mechanical theory and by the balance-equation theory. It is found that the photon absorption spectrum displays a local resonant maximum, corresponding to LO energy, and the absorption peak vanishes with increasing the electronic temperature.

  13. Evolution of absorption machines; Evolution des machines a absorption

    Energy Technology Data Exchange (ETDEWEB)

    Soide, I.; Klemsdal, E. [Gaz de France (GDF), 75 - Paris (France); Le Goff, P.; Hornut, J.M. [LSGC-ENSIC, 54 - Nancy (France)


    Most of todays absorption air-conditioning machineries use the lithium bromide-water pair. The most performing can operate at a 150-160 deg. C, the temperature being limited by the corrosion resistance of metals with respect to LiBr solutions. Also, there is a revival of interest for water-ammonia systems. These systems require the use of a rectification column which reduces the coefficient of performance. Higher thermal performances are reached with hydrocarbon pairs and ternary mixtures (water-methanol-LiBr etc..). This paper presents different schemes of refrigerating heat pumps based on these different systems. (J.S.)

  14. Unmixing chromophores in human skin with a 3D multispectral optoacoustic mesoscopy system (United States)

    Schwarz, Mathias; Aguirre, Juan; Soliman, Dominik; Buehler, Andreas; Ntziachristos, Vasilis


    The absorption of visible light by human skin is governed by a number of natural chromophores: Eumelanin, pheomelanin, oxyhemoglobin, and deoxyhemoglobin are the major absorbers in the visible range in cutaneous tissue. Label-free quantification of these tissue chromophores is an important step of optoacoustic (photoacoustic) imaging towards clinical application, since it provides relevant information in diseases. In tumor cells, for instance, there are metabolic changes (Warburg effect) compared to healthy cells, leading to changes in oxygenation in the environment of tumors. In malignant melanoma changes in the absorption spectrum have been observed compared to the spectrum of nonmalignant nevi. So far, optoacoustic imaging has been applied to human skin mostly in single-wavelength mode, providing anatomical information but no functional information. In this work, we excited the tissue by a tunable laser source in the spectral range from 413-680 nm with a repetition rate of 50 Hz. The laser was operated in wavelengthsweep mode emitting consecutive pulses at various wavelengths that allowed for automatic co-registration of the multispectral datasets. The multispectral raster-scan optoacoustic mesoscopy (MSOM) system provides a lateral resolution of <60 μm independent of wavelength. Based on the known absorption spectra of melanin, oxyhemoglobin, and deoxyhemoglobin, three-dimensional absorption maps of all three absorbers were calculated from the multispectral dataset.

  15. Influence of absorption induced thermal initiation pathway on irradiance threshold for laser induced breakdown (United States)

    Varghese, Babu; Bonito, Valentina; Jurna, Martin; Palero, Jonathan; Verhagen, Margaret Hortonand Rieko


    We investigated the influence of thermal initiation pathway on the irradiance threshold for laser induced breakdown in transparent, absorbing and scattering phantoms. We observed a transition from laser-induced optical breakdown to laser-induced thermal breakdown as the absorption coefficient of the medium is increased. We found that the irradiance threshold after correction for the path length dependent absorption and scattering losses in the medium is lower due to the thermal pathway for the generation of seed electrons compared to the laser-induced optical breakdown. Furthermore, irradiance threshold gradually decreases with the increase in the absorption properties of the medium. Creating breakdown with lower irradiance threshold that is specific at the target chromophore can provide intrinsic target selectivity and improve safety and efficacy of skin treatment methods that use laser induced breakdown. PMID:25909007

  16. TRP Channels in Skin Biology and Pathophysiology (United States)

    Caterina, Michael J.; Pang, Zixuan


    Ion channels of the Transient Receptor Potential (TRP) family mediate the influx of monovalent and/or divalent cations into cells in response to a host of chemical or physical stimuli. In the skin, TRP channels are expressed in many cell types, including keratinocytes, sensory neurons, melanocytes, and immune/inflammatory cells. Within these diverse cell types, TRP channels participate in physiological processes ranging from sensation to skin homeostasis. In addition, there is a growing body of evidence implicating abnormal TRP channel function, as a product of excessive or deficient channel activity, in pathological skin conditions such as chronic pain and itch, dermatitis, vitiligo, alopecia, wound healing, skin carcinogenesis, and skin barrier compromise. These diverse functions, coupled with the fact that many TRP channels possess pharmacologically accessible sites, make this family of proteins appealing therapeutic targets for skin disorders. PMID:27983625

  17. Antioxidants in skin ageing - Future of dermatology

    Directory of Open Access Journals (Sweden)

    Shamika M Salavkar


    Full Text Available The formation of free radicals is a widely accepted pivotal mechanism leading to skin ageing. Skin ageing is a complex, progressive, time-dependent deterioration caused by intrinsic and extrinsic factors or environmental factors. Skin is equipped with an elaborate antioxidant system that protects it from oxidative damage due to intrinsic and extrinsic factors. However, the natural antioxidant pool can be compromised or overwhelmed by oxidative stress of excess UV exposure, as well as cigarette smoke and other airborne pollutants. Topical antioxidants have been demonstrated to protect the skin from free radical damage and its regular application can actually reverse pervious photodamage. Topical antioxidants are available in over-the-counter skin care products that are aimed at preventing the clinical signs of photoageing. The present review summarises scientific literature regarding efficacy of topical antioxidants and significance of novel delivery systems for topical antioxidant delivery for combating skin ageing.

  18. Morphine metabolism in human skin microsomes. (United States)

    Heilmann, S; Küchler, S; Schäfer-Korting, M


    For patients with severe skin wounds, topically applied morphine is an option to induce efficient analgesia due to the presence of opioid receptors in the skin. However, for topical administration it is important to know whether the substance is biotransformed in the skin as this can eventually reduce the concentration of the active agent considerably. We use skin microsomes to elucidate the impact of skin metabolism on the activity of topically applied morphine. We are able to demonstrate that morphine is only glucuronidated in traces, indicating that the biotransformation in the skin can be neglected when morphine is applied topically. Hence, there is no need to take biotransformation into account when setting up the treatment regimen.

  19. TRP Channels in Skin Biology and Pathophysiology

    Directory of Open Access Journals (Sweden)

    Michael J. Caterina


    Full Text Available Ion channels of the Transient Receptor Potential (TRP family mediate the influx of monovalent and/or divalent cations into cells in response to a host of chemical or physical stimuli. In the skin, TRP channels are expressed in many cell types, including keratinocytes, sensory neurons, melanocytes, and immune/inflammatory cells. Within these diverse cell types, TRP channels participate in physiological processes ranging from sensation to skin homeostasis. In addition, there is a growing body of evidence implicating abnormal TRP channel function, as a product of excessive or deficient channel activity, in pathological skin conditions such as chronic pain and itch, dermatitis, vitiligo, alopecia, wound healing, skin carcinogenesis, and skin barrier compromise. These diverse functions, coupled with the fact that many TRP channels possess pharmacologically accessible sites, make this family of proteins appealing therapeutic targets for skin disorders.

  20. Adaptive skin detection based on online training (United States)

    Zhang, Ming; Tang, Liang; Zhou, Jie; Rong, Gang


    Skin is a widely used cue for porn image classification. Most conventional methods are off-line training schemes. They usually use a fixed boundary to segment skin regions in the images and are effective only in restricted conditions: e.g. good lightness and unique human race. This paper presents an adaptive online training scheme for skin detection which can handle these tough cases. In our approach, skin detection is considered as a classification problem on Gaussian mixture model. For each image, human face is detected and the face color is used to establish a primary estimation of skin color distribution. Then an adaptive online training algorithm is used to find the real boundary between skin color and background color in current image. Experimental results on 450 images showed that the proposed method is more robust in general situations than the conventional ones.