3D imaging of cleared human skin biopsies using light-sheet microscopy: A new way to visualize in-depth skin structure.

Science.gov (United States)

Abadie, S; Jardet, C; Colombelli, J; Chaput, B; David, A; Grolleau, J-L; Bedos, P; Lobjois, V; Descargues, P; Rouquette, J

2018-05-01

Human skin is composed of the superimposition of tissue layers of various thicknesses and components. Histological staining of skin sections is the benchmark approach to analyse the organization and integrity of human skin biopsies; however, this approach does not allow 3D tissue visualization. Alternatively, confocal or two-photon microscopy is an effective approach to perform fluorescent-based 3D imaging. However, owing to light scattering, these methods display limited light penetration in depth. The objectives of this study were therefore to combine optical clearing and light-sheet fluorescence microscopy (LSFM) to perform in-depth optical sectioning of 5 mm-thick human skin biopsies and generate 3D images of entire human skin biopsies. A benzyl alcohol and benzyl benzoate solution was used to successfully optically clear entire formalin fixed human skin biopsies, making them transparent. In-depth optical sectioning was performed with LSFM on the basis of tissue-autofluorescence observations. 3D image analysis of optical sections generated with LSFM was performed by using the Amira ® software. This new approach allowed us to observe in situ the different layers and compartments of human skin, such as the stratum corneum, the dermis and epidermal appendages. With this approach, we easily performed 3D reconstruction to visualise an entire human skin biopsy. Finally, we demonstrated that this method is useful to visualise and quantify histological anomalies, such as epidermal hyperplasia. The combination of optical clearing and LSFM has new applications in dermatology and dermatological research by allowing 3D visualization and analysis of whole human skin biopsies. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of boundary conditions on the classical skin depth and nonlocal behavior in inductively coupled plasmas

International Nuclear Information System (INIS)

Rehman, Aman-ur; Pu Yikang

2005-01-01

When the finiteness of plasma geometry is taken into account, the expression for classical skin depth is different from the one obtained for an unbounded plasma (for both the planar and cylindrical geometries). This change in the expression of the classical skin depth also changes the nonlocality parameter, which is defined as the square of the ratio of the effective mean free path to the classical skin depth. It is concluded that it is the compactness of the geometry due to the metallic boundary condition (E=0) that impacts nonlocal heating (particularly in the low-frequency regime) rather than the shape of the geometry

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

Science.gov (United States)

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

2017-11-01

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

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

Directory of Open Access Journals (Sweden)

P. Behm

2017-11-01

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

Thermal-depth matching in dynamic scene based on affine projection and feature registration

Science.gov (United States)

Wang, Hongyu; Jia, Tong; Wu, Chengdong; Li, Yongqiang

2018-03-01

This paper aims to study the construction of 3D temperature distribution reconstruction system based on depth and thermal infrared information. Initially, a traditional calibration method cannot be directly used, because the depth and thermal infrared camera is not sensitive to the color calibration board. Therefore, this paper aims to design a depth and thermal infrared camera calibration board to complete the calibration of the depth and thermal infrared camera. Meanwhile a local feature descriptors in thermal and depth images is proposed. The belief propagation matching algorithm is also investigated based on the space affine transformation matching and local feature matching. The 3D temperature distribution model is built based on the matching of 3D point cloud and 2D thermal infrared information. Experimental results show that the method can accurately construct the 3D temperature distribution model, and has strong robustness.

Thermal Depth Profiling Reconstruction by Multilayer Thermal Quadrupole Modeling and Particle Swarm Optimization

International Nuclear Information System (INIS)

Zhao-Jiang, Chen; Shu-Yi, Zhang

2010-01-01

A new hybrid inversion method for depth profiling reconstruction of thermal conductivities of inhomogeneous solids is proposed based on multilayer quadrupole formalism of thermal waves, particle swarm optimization and sequential quadratic programming. The reconstruction simulations for several thermal conductivity profiles are performed to evaluate the applicability of the method. The numerical simulations demonstrate that the precision and insensitivity to noise of the inversion method are very satisfactory. (condensed matter: structure, mechanical and thermal properties)

Approximate relationship between frequency-dependent skin depth resolved from geoelectromagnetic pedotransfer function and depth of investigation resolved from geoelectrical measurements: A case study of coastal formation, southern Nigeria

Science.gov (United States)

George, N. J.; Obiora, D. N.; Ekanem, A. M.; Akpan, A. E.

2016-10-01

The task involved in the interpretation of Vertical Electrical Sounding (VES) data is how to get unique results in the absence/limited number of borehole information, which is usually limited to information on the spot. Geological and geochemical mapping of electrical properties are usually limited to direct observations on the surface and therefore, conclusions and extrapolations that can be drawn about the system electrical characteristics and possible underlying structures may be masked as geology changes with positions. The electrical resistivity study pedotransfer functions (PTFs) have been linked with the electromagnetic (EM) resolved PTFs at chosen frequencies of skin/penetration depth corresponding to the VES resolved investigation depth in order to determine the local geological attributes of hydrogeological repository in the coastal formation dominated with fine sand. The illustrative application of effective skin depth depicts that effective skin depth has direct relation with the EM response of the local source over the layered earth and thus, can be linked to the direct current earth response functions as an aid for estimating the optimum depth and electrical parameters through comparative analysis. Though the VES and EM resolved depths of investigation at appropriate effective and theoretical frequencies have wide gaps, diagnostic relations characterising the subsurface depth of interest have been established. The determining factors of skin effect have been found to include frequency/period, resistivity/conductivity, absorption/attenuation coefficient and energy loss factor. The novel diagnostic relations and their corresponding constants between 1-D resistivity data and EM skin depth are robust PTFs necessary for checking the accuracy associated with the non-unique interpretations that characterise the 1-D resistivity data, mostly when lithostratigraphic data are not available.

Eddy-current inversion in the thin-skin limit: Determination of depth and opening for a long crack

Science.gov (United States)

Burke, S. K.

1994-09-01

A method for crack size determination using eddy-current nondestructive evaluation is presented for the case of a plate containing an infinitely long crack of uniform depth and uniform crack opening. The approach is based on the approximate solution to Maxwell's equations for nonmagnetic conductors in the limit of small skin depth and relies on least-squares polynomial fits to a normalized coil impedance function as a function of skin depth. The method is straightforward to implement and is relatively insensitive to both systematic and random errors. The procedure requires the computation of two functions: a normalizing function, which depends both on the coil parameters and the skin depth, and a crack-depth function which depends only on the coil parameters in addition to the crack depth. The practical perfomance of the method was tested using a set of simulated cracks in the form of electro-discharge machined slots in aluminum alloy plates. The crack depths and crack opening deduced from the eddy-current measurements agree with the actual crack dimensions to within 10% or better. Recommendations concerning the optimum conditions for crack sizing are also made.

Estimation of Skin to Subarachnoid Space Depth: An Observational Study.

Science.gov (United States)

Hazarika, Rajib; Choudhury, Dipika; Nath, Sangeeta; Parua, Samit

2016-10-01

In a patient, the skin to Subarachnoid Space Depth (SSD) varies considerably at different levels of the spinal cord. It also varies from patient to patient at the same vertebral level as per age, sex and Body Mass Index (BMI). Estimation of the skin to SSD reduces complications related to spinal anaesthesia. To measure the skin to SSD in the Indian population and to find a formula for predicting this depth. Three hundred adult patients belonging to American Society of Anaesthesiologist class I and II, undergoing surgery using spinal anaesthesia in various surgical specialities of Gauhati Medical College were selected by systemic sampling for this prospective, observational study. Patients were divided into three groups: Group M containing male patients, Group F containing non-pregnant female patients, and Group PF containing pregnant female's patients. SSD was measured after performing lumbar puncture. The relationship between SSD and patient characteristics were studied, correlated and statistical analysis was used to find a formula for predicting the skin to SSD. Statistical analysis was done using Statistical Package for Social Sciences (SPSS 21.0, Chicago, IL, USA). One-way ANOVA with post-hoc(Bonferroni correction factor) analysis was applied to compare the three groups. Multivariate analysis was done for the covariates followed by a multivariate regression analysis to evaluate the covariates influencing SSD for each group separately. Mean SSD was 4.37±0.31cm in the overall population. SSD in adult males was 4.49±0.19cm which was significantly longer than that observed in female's 4.18±0.39cm which was comparable with SSD in parturient 4.43±0.19 cm. The formula for predicting the skin to SSD in the male population was 1.718+0.077×BMI+0.632×Height, in nonpregnant female population was 1.828+0.077×BMI+0.018×Height+0.007×Age and 0.748+0.209×BMI+4.703×Height-0.054×weight in parturient females, respectively. Skin to SSD correlated with the BMI in all

Thermal analysis of epidermal electronic devices integrated with human skin considering the effects of interfacial thermal resistance

Science.gov (United States)

Li, Yuhang; Zhang, Jianpeng; Xing, Yufeng; Song, Jizhou

2018-05-01

Epidermal electronic devices (EEDs) have similar mechanical properties as those of human skin such that they can be integrated with human skin for potential applications in monitoring of human vital signs for diagnostic, therapeutic or surgical functions. Thermal management is critical for EEDs in these applications since excessive heating may cause discomfort. Comprehensive analytical studies, finite element analysis and experiments are carried out to study the effects of interfacial thermal resistance between EEDs and human skin on thermal properties of the EED/skin system in this paper. The coupling between the Fourier heat transfer in EEDs and the bio-heat transfer in human skin is accounted in the analytical model based on the transfer matrix method to give accurate predictions on temperatures, which agree well with finite element analysis and experimental measurements. It is shown that the maximum temperature increase of the EED for the case of imperfect bonding between EED and skin is much higher than that of perfect bonding. These results may help the design of EEDs in bi-integrated applications and suggest a valuable route to evaluate the bonding condition between EEDs and biological tissues.

The dependence of percentage depth dose on the source-to-skin ...

African Journals Online (AJOL)

The variation of percentage depth dose (PDD) with source-to-skin distance (SSD) for kilovoltage X-rays used in radiotherapy has been investigated. Based on physical parameters of photon fluence, absorption and scatter during interaction of radiation with tissue, a mathematical model was developed to predict the PDDs at ...

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

Science.gov (United States)

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

2013-10-01

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

Sunburn, Thermal, and Chemical Injuries to the Skin.

Science.gov (United States)

Monseau, Aaron J; Reed, Zebula M; Langley, Katherine Jane; Onks, Cayce

2015-12-01

Sunburn, thermal, and chemical injuries to the skin are common in the United States and worldwide. Initial management is determined by type and extent of injury with special care to early management of airway, breathing, and circulation. Fluid management has typically been guided by the Parkland formula, whereas some experts now question this. Each type of skin injury has its own pathophysiology and resultant complications. All primary care physicians should have at least a basic knowledge of management of acute and chronic skin injuries. Copyright © 2015 Elsevier Inc. All rights reserved.

Study of skin model and geometry effects on thermal performance of thermal protective fabrics

Science.gov (United States)

Zhu, Fanglong; Ma, Suqin; Zhang, Weiyuan

2008-05-01

Thermal protective clothing has steadily improved over the years as new materials and improved designs have reached the market. A significant method that has brought these improvements to the fire service is the NFPA 1971 standard on structural fire fighters’ protective clothing. However, this testing often neglects the effects of cylindrical geometry on heat transmission in flame resistant fabrics. This paper deals with methods to develop cylindrical geometry testing apparatus incorporating novel skin bioheat transfer model to test flame resistant fabrics used in firefighting. Results show that fabrics which shrink during the test can have reduced thermal protective performance compared with the qualities measured with a planar geometry tester. Results of temperature differences between skin simulant sensors of planar and cylindrical tester are also compared. This test method provides a new technique to accurately and precisely characterize the thermal performance of thermal protective fabrics.

Preterm infant thermal care: differing thermal environments produced by air versus skin servo-control incubators.

Science.gov (United States)

Thomas, K A; Burr, R

1999-06-01

Incubator thermal environments produced by skin versus air servo-control were compared. Infant abdominal skin and incubator air temperatures were recorded from 18 infants in skin servo-control and 14 infants in air servo-control (26- to 29-week gestational age, 14 +/- 2 days postnatal age) for 24 hours. Differences in incubator and infant temperature, neutral thermal environment (NTE) maintenance, and infant and incubator circadian rhythm were examined using analysis of variance and scatterplots. Skin servo-control resulted in more variable air temperature, yet more stable infant temperature, and more time within the NTE. Circadian rhythm of both infant and incubator temperature differed by control mode and the relationship between incubator and infant temperature rhythms was a function of control mode. The differences between incubator control modes extend beyond temperature stability and maintenance of NTE. Circadian rhythm of incubator and infant temperatures is influenced by incubator control.

Female upper body and breast skin temperature and thermal comfort following exercise.

Science.gov (United States)

Ayres, B; White, J; Hedger, W; Scurr, J

2013-01-01

Breast support reduces breast pain and movement during exercise, however, an extra layer of clothing may affect thermoregulation. This preliminary study investigated female upper body and breast skin temperature and thermal comfort following short-duration exercise. Eight female participants with C-cup breasts had thermal images (infra-red camera, FLIR systems) of the bare breasts, the breasts in two sports bras (composite and polyester) and the abdomen, taken before and after 20 min of exercise at 28(o)C. Following exercise, bare-breast, bra and abdomen temperatures reduced by 0.61(o)C, 0.92(o)C and 2.06(o)C, respectively. The polyester sports bra demonstrated greater thermal comfort and enabled a greater change in skin temperature than the composite sports bra. It is concluded that following short-duration exercise, sports bras reduced the cooling ability of the breast. Material properties of the bras affect thermal comfort and post-exercise skin temperature; this should be an important consideration for sports bra manufacturers. This study investigates the effect of sports bras on thermal regulation of the breast following exercise. Sports bras negatively affected the cooling ability of the skin on the breast, with the material properties of the bra affecting thermal comfort following exercise. These results present important considerations for sports bra manufacturers.

Investigating skin penetration depth and shape following needle-free injection at different pressures: A cadaveric study.

Science.gov (United States)

Seok, Joon; Oh, Chang Taek; Kwon, Hyun Jung; Kwon, Tae Rin; Choi, Eun Ja; Choi, Sun Young; Mun, Seog Kyun; Han, Seung-Ho; Kim, Beom Joon; Kim, Myeung Nam

2016-08-01

The effectiveness of needle-free injection devices in neocollagenesis for treating extended skin planes is an area of active research. It is anticipated that needle-free injection systems will not only be used to inject vaccines or insulin, but will also greatly aid skin rejuvenation when used to inject aesthetic materials such as hyaluronic acid, botulinum toxin, and placental extracts. There has not been any specific research to date examining how materials penetrate the skin when a needle-free injection device is used. In this study, we investigated how material infiltrates the skin when it is injected into a cadaver using a needle-free device. Using a needle-free injector (INNOJECTOR™; Amore Pacific, Seoul, Korea), 0.2 ml of 5% methylene blue (MB) or latex was injected into cheeks of human cadavers. The device has a nozzle diameter of 100 µm and produces a jet with velocity of 180 m/s. This jet penetrates the skin and delivers medicine intradermally via liquid propelled by compressed gasses. Materials were injected at pressures of 6 or 8.5 bars, and the injection areas were excised after the procedure. The excised areas were observed visually and with a phototrichogram to investigate the size, infiltration depth, and shape of the hole created on the skin. A small part of the area that was excised was magnified and stained with H&E (×40) for histological examination. We characterized the shape, size, and depth of skin infiltration following injection of 5% MB or latex into cadaver cheeks using a needle-free injection device at various pressure settings. Under visual inspection, the injection at 6 bars created semi-circle-shaped hole that penetrated half the depth of the excised tissue, while injection at 8.5 bars created a cylinder-shaped hole that spanned the entire depth of the excised tissue. More specific measurements were collected using phototrichogram imaging. The shape of the injection entry point was consistently spherical regardless of the

Thermal Skin Damage During Reirradiation and Hyperthermia Is Time-Temperature Dependent

Energy Technology Data Exchange (ETDEWEB)

Bakker, Akke, E-mail: akke.bakker@amc.uva.nl [Department of Radiation Oncology, Academic Medical Center (AMC), Amsterdam (Netherlands); Kolff, M. Willemijn [Department of Radiation Oncology, Academic Medical Center (AMC), Amsterdam (Netherlands); Holman, Rebecca [Clinical Research Unit, Academic Medical Center (AMC), Amsterdam (Netherlands); Leeuwen, Caspar M. van; Korshuize-van Straten, Linda; Kroon-Oldenhof, Rianne de; Rasch, Coen R.N.; Tienhoven, Geertjan van; Crezee, Hans [Department of Radiation Oncology, Academic Medical Center (AMC), Amsterdam (Netherlands)

2017-06-01

Purpose: To investigate the relationship of thermal skin damage (TSD) to time–temperature isoeffect levels for patients with breast cancer recurrence treated with reirradiation plus hyperthermia (reRT + HT), and to investigate whether the treatment history of previous treatments (scar tissue) is a risk factor for TSD. Methods and Materials: In this observational study, temperature characteristics of hyperthermia sessions were analyzed in 262 patients with recurrent breast cancer treated in the AMC between 2010 and 2014 with reirradiation and weekly hyperthermia for 1 hour. Skin temperature was measured using a median of 42 (range, 29-82) measurement points per hyperthermia session. Results: Sixty-eight patients (26%) developed 79 sites of TSD, after the first (n=26), second (n=17), third (n=27), and fourth (n=9) hyperthermia session. Seventy percent of TSD occurred on or near scar tissue. Scar tissue reached higher temperatures than other skin tissue (0.4°C, P<.001). A total of 102 measurement points corresponded to actual TSD sites in 35 of 79 sessions in which TSD developed. Thermal skin damage sites had much higher maximum temperatures than non-TSD sites (2.8°C, P<.001). Generalized linear mixed models showed that the probability of TSD is related to temperature and thermal dose values (P<.001) and that scar tissue is more at risk (odds ratio 0.4, P<.001). Limiting the maximum temperature of a measurement point to 43.7°C would mean that the probability of observing TSD was at most 5%. Conclusion: Thermal skin damage during reRT + HT for recurrent breast cancer was related to higher local temperatures and time–temperature isoeffect levels. Scar tissue reached higher temperatures than other skin tissue, and TSD occurred at lower temperatures and thermal dose values in scar tissue compared with other skin tissue. Indeed, TSD developed often on and around scar tissue from previous surgical procedures.

Laser-induced thermal damage of skin. Final report, September 1976--April 1977

Energy Technology Data Exchange (ETDEWEB)

Takata, A.N.; Zaneveld, L.; Richter, W.

1977-12-01

A computerized model was developed for predicting thermal damage of skin by laser exposures. Thermal, optical, and physiological data are presented for the model. Model predictions of extent of irreversible damage were compared with histologic determinations of the extent of damage produced in pig skin by carbon dioxide and ruby lasers. (Author)

Comparison of human skin opto-thermal response to near-infrared and visible laser irradiations: a theoretical investigation

Energy Technology Data Exchange (ETDEWEB)

Dai Tianhong [Department of Bioengineering, Rice University, Houston, TX 77251 (United States); Pikkula, Brian M [Department of Bioengineering, Rice University, Houston, TX 77251 (United States); Wang, Lihong V [Department of Biomedical Engineering, Texas A and M University, College Station, TX 77843 (United States); Anvari, Bahman [Department of Bioengineering, Rice University, Houston, TX 77251 (United States)

2004-11-07

Near-infrared wavelengths are absorbed less by epidermal melanin, and penetrate deeper into human skin dermis and blood than visible wavelengths. Therefore, laser irradiation using near-infrared wavelengths may improve the therapeutic outcome of cutaneous hyper-vascular malformations in moderately to heavily pigmented skin patients and those with large-sized blood vessels or blood vessels extending deeply into the skin. A mathematical model composed of a Monte Carlo algorithm to estimate the distribution of absorbed light, numerical solution of a bio-heat diffusion equation to calculate the transient temperature distribution, and a damage integral based on an empirical Arrhenius relationship to quantify the tissue damage was utilized to investigate the opto-thermal response of human skin to near-infrared and visible laser irradiations in conjunction with cryogen spray cooling. In addition, the thermal effects of a single continuous laser pulse and micropulse-composed laser pulse profiles were compared. Simulation results indicated that a 940 nm wavelength induces improved therapeutic outcome compared with a 585 and 595 nm wavelengths for the treatment of patients with large-sized blood vessels and moderately to heavily pigmented skin. On the other hand, a 585 nm wavelength shows the best efficacy in treating small-sized blood vessels, as characterized by the largest laser-induced blood vessel damage depth compared with 595 and 940 nm wavelengths. Dermal blood content has a considerable effect on the threshold incident dosage for epidermal damage, while the effect of blood vessel size is minimal. For the same macropulse duration and incident dosage, a micropulse-composed pulse profile results in higher peak temperature at the basal layer of skin epidermis than an ideal single continuous pulse profile.

SU-E-T-387: Evaluation of Effective Treatment Depth in Skin Cancer Treatments with Xoft Electronic Brachytherapy

International Nuclear Information System (INIS)

Dragojevic, I; Hoisak, J

2015-01-01

Purpose: To evaluate changes in the percent depth dose (PDD) and effective depth of treatment based on exerted force by applicator on the skin during treatments of skin cancer with Xoft Electronic Brachytherapy. Methods: To simulate compressible tissue, 5mm tissue-equivalent bolus was used. An ion chamber (Soft X-ray Chamber, PTW) and electrometer (Max 4000, Standard Imaging) were used for output measurements. Measurements were done for all available Xoft surface applicators (10, 20, 35, and 50mm cones) with plastic endcap. Fig1 shows the experimental setup. The PDD was measured first with no or minimal pressure of the applicator on the bolus, followed by increasing uniform pressure on the applicator applied with custom cerrobend weights. The measurements were used to calculate the effective PDD and effective depth. Results: Force applied with the applicator was plotted against the change in PDD relative to the PDD when no force is applied. For the 10mm cone, moderate force of 5N can change the PDD by more than 20%, (Fig2). The effect is also pronounced for the 20mm cone, while it is minimal for the 35 and 50mm cones. Even when only moderate force is applied, the effective prescription depth can be changed by a several millimeters, which is on the order of the typical prescription depth (Fig3). Conclusion: Based on the results of this simulation, excessive pressure applied on the patient’s skin by the applicator cone can drastically alter the PDD and effective treatment depth. The effect is most pronounced for the 10mm cone, and to a lesser extent, 20mm, which is significant as these cones tend to be used most frequently in the clinic. Applicator placement therefore may Result in significant consequences such as excessive dose to target, severe skin reaction, permanent discoloration, skin indentation, and poor overall cosmesis upon completion of treatment

Photothermal radiometric determination of thermal diffusivity depth profiles in a dental resin

International Nuclear Information System (INIS)

MartInez-Torres, P; Alvarado-Gil, J J; Mandelis, A

2010-01-01

The depth of curing due to photopolymerization in a commercial dental resin is studied using photothermal radiometry. The sample consists of a thick layer of resin on which a thin metallic layer is deposited guaranteeing full opacity of the sample. In this case, purely thermal-wave inverse problem techniques without the interference of optical profiles can be used. Thermal profiles are obtained by heating the coating with a modulated laser beam and performing a modulation frequency scan. Before each frequency scan, photopolymerization was induced using a high power blue LED. However due to the fact that dental resins are highly light dispersive materials, the polymerization process depends strongly on the optical absorption coefficient inducing a depth dependent thermal diffusion in the sample. It is shown that using a robust depth profilometric inverse method one can reconstruct the thermal diffusivity profile of the photopolymerized resin.

Evaluation of Perfusion and Thermal Parameters of Skin Tissue Using Cold Provocation and Thermographic Measurements

Directory of Open Access Journals (Sweden)

Strąkowska Maria

2016-09-01

Full Text Available Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.

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

Science.gov (United States)

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

2014-09-01

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

Effects of Thermal Resistance on One-Dimensional Thermal Analysis of the Epidermal Flexible Electronic Devices Integrated with Human Skin

Science.gov (United States)

Li, He; Cui, Yun

2017-12-01

Nowadays, flexible electronic devices are increasingly used in direct contact with human skin to monitor the real-time health of human body. Based on the Fourier heat conduction equation and Pennes bio-heat transfer equation, this paper deduces the analytical solutions of one - dimensional heat transfer for flexible electronic devices integrated with human skin under the condition of a constant power. The influence of contact thermal resistance between devices and skin is considered as well. The corresponding finite element model is established to verify the correctness of analytical solutions. The results show that the finite element analysis agrees well with the analytical solution. With bigger thermal resistance, temperature increase of skin surface will decrease. This result can provide guidance for the design of flexible electronic devices to reduce the negative impact that exceeding temperature leave on human skin.

The Response of the Ocean Thermal Skin Layer to Air-Sea Surface Heat Fluxes

Science.gov (United States)

Wong, Elizabeth Wing-See

There is much evidence that the ocean is heating as a result of an increase in concentrations of greenhouse gases (GHGs) in the atmosphere from human activities. GHGs absorb infrared radiation and re-emit infrared radiation back to the ocean's surface which is subsequently absorbed. However, the incoming infrared radiation is absorbed within the top micrometers of the ocean's surface which is where the thermal skin layer exists. Thus the incident infrared radiation does not directly heat the upper few meters of the ocean. We are therefore motivated to investigate the physical mechanism between the absorption of infrared radiation and its effect on heat transfer at the air-sea boundary. The hypothesis is that since heat lost through the air-sea interface is controlled by the thermal skin layer, which is directly influenced by the absorption and emission of infrared radiation, the heat flow through the thermal skin layer adjusts to maintain the surface heat loss, assuming the surface heat loss does not vary, and thus modulates the upper ocean heat content. This hypothesis is investigated through utilizing clouds to represent an increase in incoming longwave radiation and analyzing retrieved thermal skin layer vertical temperature profiles from a shipboard infrared spectrometer from two research cruises. The data are limited to night-time, no precipitation and low winds of less than 2 m/s to remove effects of solar radiation, wind-driven shear and possibilities of thermal skin layer disruption. The results show independence of the turbulent fluxes and emitted radiation on the incident radiative fluxes which rules out the immediate release of heat from the absorption of the cloud infrared irradiance back into the atmosphere through processes such as evaporation and increase infrared emission. Furthermore, independence was confirmed between the incoming and outgoing radiative flux which implies the heat sink for upward flowing heat at the air-sea interface is more

Depth distributions of light action spectra for skin chromophores

Science.gov (United States)

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

2010-03-01

Light action spectra over wavelengths of 300-1000 nm are calculated for components of the human cutaneous covering: melanin, basal (bloodless) tissue, and blood oxy- and deoxyhemoglobin. The transformation of the spectra with depth in biological tissue results from two factors. The first is the wavelength dependence of the absorption coefficient corresponding to a particular skin chromophore and the second is the spectral selectivity of the radiation flux in biological tissue. This factor is related to the optical properties of all chromophores. A significant change is found to take place in the spectral distribution of absorbed radiant power with increasing depth. The action spectrum of light for the molecular oxygen contained in all components of biological tissue is also studied in the 625-645 nm range. The spectra are found to change with both the volume fraction of blood vessels and the degree of oxygenation of the blood. These results are useful for analyzing processes associated with optical absorption that are possible mechanisms for the interaction of light with biological tissues: photodissociation of oxyhemoglobin and the light-oxygen effect.

Tri-modal Person Re-identification with RGB, Depth and Thermal Features

DEFF Research Database (Denmark)

Møgelmose, Andreas; Bahnsen, Chris; Moeslund, Thomas B.

2013-01-01

Person re-identification is about recognizing people who have passed by a sensor earlier. Previous work is mainly based on RGB data, but in this work we for the first time present a system where we combine RGB, depth, and thermal data for re-identification purposes. First, from each of the three...... modalities, we obtain some particular features: from RGB data, we model color information from different regions of the body, from depth data, we compute different soft body biometrics, and from thermal data, we extract local structural information. Then, the three information types are combined in a joined...

Confocal Raman Microspectroscopy: The Measurement of VX Depth Profiles in Hairless Guinea Pig Skin and the Evaluation of RSDL

Science.gov (United States)

2015-02-01

USAMRICD-TR-15-01 Confocal Raman Microspectroscopy: The Measurement of VX Depth Profiles in Hairless Guinea Pig Skin and the Evaluation...5a. CONTRACT NUMBER guinea pig skin and the evaluation of RSDL 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Braue, EH...upper skin layers of hairless guinea pigs and to determine the ability of Reactive Skin Decontamination Lotion (RSDL) to remove or degrade VX from

The dependence of skin lesions on the depth-dose distribution from β-irradiation of people in the Chernobyl nuclear power plant accident

International Nuclear Information System (INIS)

Barabanova, A.

1990-01-01

A detailed study was made of conditions of exposure of 56 Chernobyl victims who suffered skin radiation lesions. The most typical conditions were experimentally reconstructed to investigate specific characteristics of dose distribution to the skin according to depth for different exposure conditions. Absorbed doses at depths of 7 mg cm -2 and 150 mg cm -2 were calculated on the basis of measurements with multilayer skin dosemeters. Patients were classified into four groups. Dosimetric characteristics for each group were compared with clinical pictures to establish critical factors in the occurrence of lesions. It was demonstrated that depth-dose distribution of β-radiation to the skin is of great influence not only for early effects of radiation but also for later effects. Radiation lesions in the skin led to death if the area of the lesions exceeded about 50% total body surface, and if doses to the skin were about 200-300 Gy at 7 mg cm -2 and more than about 30 Gy at 150 mg cm -2 . (author)

The use of thermal imaging to monitoring skin temperature during cryotherapy: A systematic review

Science.gov (United States)

Matos, Filipe; Neves, Eduardo Borba; Norte, Marco; Rosa, Claudio; Reis, Victor Machado; Vilaça-Alves, José

2015-11-01

Cryotherapy has been applied on clinical injuries and as a method for exercise recovery. It is aimed to reduce edema, nervous conduction velocity, and tissue metabolism, as well as to accelerate the recovery process of the muscle injury induced by exercise. Objective: This review aim to investigate the applicability of thermal imaging as a method for monitoring skin temperature during cryotherapy. Method: Search the Web of Science database using the terms "Cryotherapy", "Thermography", "Thermal Image" and "Cooling". Results: Nineteen studies met the inclusion criteria and pass the PEDro scale quality evaluation. Evidence support the use of thermal imaging as a method for monitoring the skin temperature during cryotherapy, and it is superior to other contact methods and subjective methods of assessing skin temperature. Conclusion: Thermography seems to be an efficient, trustworthy and secure method in order to monitoring skin temperature during cryotherapy application. Evidence supports the use of thermography in detriment of contact methods as well as other subjective ones.

Using Upper Extremity Skin Temperatures to Assess Thermal Comfort in Office Buildings in Changsha, China.

Science.gov (United States)

Wu, Zhibin; Li, Nianping; Cui, Haijiao; Peng, Jinqing; Chen, Haowen; Liu, Penglong

2017-09-21

Existing thermal comfort field studies are mainly focused on the relationship between the indoor physical environment and the thermal comfort. In numerous chamber experiments, physiological parameters were adopted to assess thermal comfort, but the experiments' conclusions may not represent a realistic thermal environment due to the highly controlled thermal environment and few occupants. This paper focuses on determining the relationships between upper extremity skin temperatures (i.e., finger, wrist, hand and forearm) and the indoor thermal comfort. Also, the applicability of predicting thermal comfort by using upper extremity skin temperatures was explored. Field studies were performed in office buildings equipped with split air-conditioning (SAC) located in the hot summer and cold winter (HSCW) climate zone of China during the summer of 2016. Psychological responses of occupants were recorded and physical and physiological factors were measured simultaneously. Standard effective temperature (SET*) was used to incorporate the effect of humidity and air velocity on thermal comfort. The results indicate that upper extremity skin temperatures are good indicators for predicting thermal sensation, and could be used to assess the thermal comfort in terms of physiological mechanism. In addition, the neutral temperature was 24.7 °C and the upper limit for 80% acceptability was 28.2 °C in SET*.

Using Upper Extremity Skin Temperatures to Assess Thermal Comfort in Office Buildings in Changsha, China

Directory of Open Access Journals (Sweden)

Zhibin Wu

2017-09-01

Full Text Available Existing thermal comfort field studies are mainly focused on the relationship between the indoor physical environment and the thermal comfort. In numerous chamber experiments, physiological parameters were adopted to assess thermal comfort, but the experiments’ conclusions may not represent a realistic thermal environment due to the highly controlled thermal environment and few occupants. This paper focuses on determining the relationships between upper extremity skin temperatures (i.e., finger, wrist, hand and forearm and the indoor thermal comfort. Also, the applicability of predicting thermal comfort by using upper extremity skin temperatures was explored. Field studies were performed in office buildings equipped with split air-conditioning (SAC located in the hot summer and cold winter (HSCW climate zone of China during the summer of 2016. Psychological responses of occupants were recorded and physical and physiological factors were measured simultaneously. Standard effective temperature (SET* was used to incorporate the effect of humidity and air velocity on thermal comfort. The results indicate that upper extremity skin temperatures are good indicators for predicting thermal sensation, and could be used to assess the thermal comfort in terms of physiological mechanism. In addition, the neutral temperature was 24.7 °C and the upper limit for 80% acceptability was 28.2 °C in SET*.

How accurate are measurements of skin-lesion depths on prebiopsy supine chest computed tomography for transthoracic needle biopsies?

International Nuclear Information System (INIS)

Cheung, Joo Yeon; Kim, Yookyung; Shim, Sung Shine; Lee, Jin Hwa; Chang, Jung Hyun; Ryu, Yon Ju; Lee, Rena J.

2012-01-01

Aim: To evaluate the accuracy of depth measurements on supine chest computed tomography (CT) for transthoracic needle biopsy (TNB). Materials and methods: We measured skin-lesion depths from the skin surface to nodules on both prebiopsy supine CT scans and CT scans obtained during cone beam CT-guided TNB in the supine (n = 29) or prone (n = 40) position in 69 patients, and analyzed the differences between the two measurements, based on patient position for the biopsy and lesion location. Results: Skin-lesion depths measured on prebiopsy supine CT scans were significantly larger than those measured on CT scans obtained during TNB in the prone position (p < 0.001; mean difference ± standard deviation (SD), 6.2 ± 5.7 mm; range, 0–18 mm), but the differences showed marginal significance in the supine position (p = 0.051; 3.5 ± 3.9 mm; 0–13 mm). Additionally, the differences were significantly larger for the upper (mean ± SD, 7.8 ± 5.7 mm) and middle (10.1 ± 6.5 mm) lung zones than for the lower lung zones (3.1 ± 3.3 mm) in the prone position (p = 0.011), and were larger for the upper lung zone (4.6 ± 5.0 mm) than for the middle (2.4 ± 2.0 mm) and lower (2.3 ± 2.3 mm) lung zones in the supine position (p = 0.004). Conclusions: Skin-lesion depths measured on prebiopsy supine chest CT scans were inaccurate for TNB in the prone position, particularly for nodules in the upper and middle lung zones.

Magnetic-field enhancement beyond the skin-depth limit

Science.gov (United States)

Shin, Jonghwa; Park, Namkyoo; Fan, Shanhui; Lee, Yong-Hee

2010-02-01

Electric field enhancement has been actively studied recently and many metallic structures that are capable of locally enhancing electric field have been reported. The Babinet's principle can be utilized, especially in the form of Booker's extension, to transform the known electric field enhancing structures into magnetic field enhancing structures. The authors explain this transformation process and discuss the regime in which this principle breaks down. Unless the metals used can be well approximated with a PEC model, the principle's predictions fails to hold true. Authors confirm this aspect using numerical simulations based on realistic material parameters for actual metals. There is large discrepancy especially when the structural dimensions are comparable or less than the skin-depth at the wavelength of interest. An alternative way to achieve magnetic field enhancement is presented and the design of a connected bow-tie structure is proposed as an example. FDTD simulation results confirm the operation of the proposed structure.

Can thermal lasers promote skin wound healing?

Science.gov (United States)

Capon, Alexandre; Mordon, Serge

2003-01-01

Lasers are now widely used for treating numerous cutaneous lesions, for scar revision (hypertrophic and keloid scars), for tissue welding, and for skin resurfacing and remodeling (wrinkle removal). In these procedures lasers are used to generate heat. The modulation of the effect (volatilization, coagulation, hyperthermia) of the laser is obtained by using different wavelengths and laser parameters. The heat source obtained by conversion of light into heat can be very superficial, yet intense, if the laser light is well absorbed (far-infrared:CO(2) or Erbium:Yttrium Aluminum Garnet [Er:YAG] lasers), or it can be much deeper and less intense if the laser light is less absorbed by the skin (visible or near-infrared). Lasers transfer energy, in the form of heat, to surrounding tissues and, regardless of the laser used, a 45-50 degrees C temperature gradient will be obtained in the surrounding skin. If a wound healing process exists, it is a result of live cells reacting to this low temperature increase. The generated supraphysiologic level of heat is able to induce a heat shock response (HSR), which can be defined as the temporary changes in cellular metabolism. These changes are rapid and transient, and are characterized by the production of a small family of proteins termed the heat shock proteins (HSP). Recent experimental studies have clearly demonstrated that HSP 70, which is over-expressed following laser irradiation, could play a role with a coordinated expression of other growth factors such as transforming growth factor (TGF)-beta. TGF-beta is known to be a key element in the inflammatory response and the fibrogenic process. In this process, the fibroblasts are the key cells since they produce collagen and extracellular matrix. In conclusion, the analysis of the literature, and the fundamental considerations concerning the healing process when using thermal lasers, are in favor of a modification of the growth factors synthesis after laser irradiation, induced

Validity of reciprocity rule on mouse skin thermal damage due to CO2 laser irradiation

Science.gov (United States)

Parvin, P.; Dehghanpour, H. R.; Moghadam, M. S.; Daneshafrooz, V.

2013-07-01

CO2 laser (10.6 μm) is a well-known infrared coherent light source as a tool in surgery. At this wavelength there is a high absorbance coefficient (860 cm-1), because of vibration mode resonance of H2O molecules. Therefore, the majority of the irradiation energy is absorbed in the tissue and the temperature of the tissue rises as a function of power density and laser exposure duration. In this work, the tissue damage caused by CO2 laser (1-10 W, ˜40-400 W cm-2, 0.1-6 s) was measured using 30 mouse skin samples. Skin damage assessment was based on measurements of the depth of cut, mean diameter of the crater and the carbonized layer. The results show that tissue damage as assessed above parameters increased with laser fluence and saturated at 1000 J cm-2. Moreover, the damage effect due to high power density at short duration was not equivalent to that with low power density at longer irradiation time even though the energy delivered was identical. These results indicate the lack of validity of reciprocity (Bunsen-Roscoe) rule for the thermal damage.

Thermal Effect of Pulsed Laser on Human Skin

OpenAIRE

N. C. Majumdar; V. K. Kochhar

1985-01-01

An attempt has been made to derive from theoretical considerations, some idea about safety limits of exposure with regard to radiant energy skin burns. This may be regarded as a preliminary enquiry in respect of thermal tissue damage by pulsed laser radiation, since the effects of isolated single pulses from ruby laser only have been considered. The study needs to be extended to other wavelengths as well as to trains of pulses.

Composite depth dose measurement for total skin electron (TSE) treatments using radiochromic film

International Nuclear Information System (INIS)

Gamble, Lisa M; Farrell, Thomas J; Jones, Glenn W; Hayward, Joseph E

2003-01-01

Total skin electron (TSE) radiotherapy is routinely used to treat cutaneous T-cell lymphomas and can be implemented using a modified Stanford technique. In our centre, the composite depth dose for this technique is achieved by a combination of two patient positions per day over a three-day cycle, and two gantry angles per patient position. Due to patient morphology, underdosed regions typically occur and have historically been measured using multiple thermoluminescent dosimeters (TLDs). We show that radiochromic film can be used as a two-dimensional relative dosimeter to measure the percent depth dose in TSE radiotherapy. Composite depth dose curves were measured in a cylindrical, polystyrene phantom and compared with TLD data. Both multiple films (1 film per day) and a single film were used in order to reproduce a realistic clinical scenario. First, three individual films were used to measure the depth dose, one per treatment day, and then compared with TLD data; this comparison showed a reasonable agreement. Secondly, a single film was used to measure the dose delivered over three daily treatments and then compared with TLD data; this comparison showed good agreement throughout the depth dose, which includes doses well below 1 Gy. It will be shown that one piece of radiochromic film is sufficient to measure the composite percent depth dose for a TSE beam, hence making radiochromic film a suitable candidate for monitoring underdosed patient regions

Thermal time constant: optimising the skin temperature predictive modelling in lower limb prostheses using Gaussian processes.

Science.gov (United States)

Mathur, Neha; Glesk, Ivan; Buis, Arjan

2016-06-01

Elevated skin temperature at the body/device interface of lower-limb prostheses is one of the major factors that affect tissue health. The heat dissipation in prosthetic sockets is greatly influenced by the thermal conductive properties of the hard socket and liner material employed. However, monitoring of the interface temperature at skin level in lower-limb prosthesis is notoriously complicated. This is due to the flexible nature of the interface liners used which requires consistent positioning of sensors during donning and doffing. Predicting the residual limb temperature by monitoring the temperature between socket and liner rather than skin and liner could be an important step in alleviating complaints on increased temperature and perspiration in prosthetic sockets. To predict the residual limb temperature, a machine learning algorithm - Gaussian processes is employed, which utilizes the thermal time constant values of commonly used socket and liner materials. This Letter highlights the relevance of thermal time constant of prosthetic materials in Gaussian processes technique which would be useful in addressing the challenge of non-invasively monitoring the residual limb skin temperature. With the introduction of thermal time constant, the model can be optimised and generalised for a given prosthetic setup, thereby making the predictions more reliable.

Influence of laser wavelength on the thermal responses of port wine stain lesions in light, moderate and heavy pigmented skin

International Nuclear Information System (INIS)

Li, D.; Chen, B.; Wu, W.J.; Ying, Z.X.

2017-01-01

Highlights: • Laser surgery for port wine stain (PWS) was studied by local non-equilibrium theory. • Wavelength selection in laser surgery under various skin pigmentation was explored. • High pigmented skin prefers to 585 nm rather then 595 nm. • Dual-wavelength laser (585/595 + 1064 nm) has better clinic effect than single one. • Deep buried blood vessels can be damaged by 595/1064 nm dual-wavelength laser. - Abstract: Pulsed dye laser (PDL) in visible band (e.g. 585 or 595 nm) together with cryogen spray cooling has become the golden standard for treatment of vascular malformation such as port wine stain (PWS). However, due to the limited energy penetration depth of the PDL, deeply buried blood vessels are likely to survive from the laser irradiation. Nd:YAG laser in near infrared (1064 nm) has great potential in the laser treatment of PWS due to its deeper penetration depth. In this study, the influence of laser wavelength in treating PWS lesions with various melanin concentrations in epidermis was theoretically investigated by a two-temperature model following the local thermal non-equilibrium theory of porous media. The results showed that deeply buried blood vessels can be coagulated by dual-wavelength laser combing 585 or 595 nm with 1064 nm laser. Furthermore, the therapeutic results by dual-wavelength laser were highly related to the melanin concentration in epidermis. In the light and moderate pigmented skin, the 595/1064 nm dual-wavelength laser showed better treatment effect in treating PWS with deeply-buried blood vessels than of 585/1064 nm dual-wavelength laser. For a high pigmented skin, the 585/1064 nm dual-wavelength laser showed better treatment effect than 595/1064 nm dual-wavelength laser.

The human thermoneutral and thermal comfort zones: Thermal comfort in your own skin blood flow.

Science.gov (United States)

Schlader, Zachary J

2015-01-01

Human thermoregulation is achieved via autonomic and behavioral responses. Autonomic responses involve 2 synchronous 'components'. One counteracts large thermal perturbations, eliciting robust heat loss or gain (i.e., sweating or shivering). The other fends off smaller insults, relying solely on changes in sensible heat exchange (i.e., skin blood flow). This sensible component occurs within the thermoneutral zone [i.e., the ambient temperature range in which temperature regulation is achieved only by sensible heat transfer, without regulatory increases in metabolic heat production (e.g., shivering) or evaporative heat loss (e.g., sweating)].(1) The combination of behavior and sensible heat exchange permits a range of conditions that are deemed thermally comfortable, which is defined as the thermal comfort zone.(1) Notably, we spend the majority of our lives within the thermoneutral and thermal comfort zones. It is only when we are unable to stay within these zones that deleterious health and safety outcomes can occur (i.e., hypo- or hyperthermia). Oddly, although the thermoneutral zone and thermal preference (a concept similar to the thermal comfort zone) has been extensively studied in non-human animals, our understanding of human thermoregulation within the thermoneutral and thermal comfort zones remains rather crude.

Degree of skin denervation and its correlation to objective thermal sensory test in leprosy patients.

Directory of Open Access Journals (Sweden)

Ismael Alves Rodrigues Júnior

Full Text Available BACKGROUND: Leprosy is an infectious disease affecting skin and peripheral nerves resulting in increased morbidity and physical deformities. Early diagnosis provides opportune treatment and reduces its complications, relying fundamentally on the demonstration of impaired sensation in suggestive cutaneous lesions. The loss of tactile sensitivity in the lesions is preceded by the loss of thermal sensitivity, stressing the importance of the thermal test in the suspicious lesions approach. The gold-standard method for the assessment of thermal sensitivity is the quantitative sensory test (QST. Morphological study may be an alternative approach to access the thin nerve fibers responsible for thermal sensitivity transduction. The few studies reported in leprosy patients pointed out a rarefaction of thin dermo-epidermal fibers in lesions, but used semi-quantitative evaluation methods. METHODOLOGY/PRINCIPAL FINDINGS: This work aimed to study the correlation between the degree of thermal sensitivity impairment measured by QST and the degree of denervation in leprosy skin lesions, evaluated by immunohistochemistry anti-PGP 9.5 and morphometry. Twenty-two patients were included. There were significant differences in skin thermal thresholds among lesions and contralateral skin (cold, warm, cold induced pain and heat induced pain. The mean reduction in the density of intraepidermal and subepidermal fibers in lesions was 79.5% (SD = 19.6 and 80.8% (SD = 24.9, respectively. CONCLUSIONS/SIGNIFICANCE: We observed a good correlation between intraepidermal and subepidermal fibers deficit, but no correlation between these variables and those accounting for the degree of impairment in thermal thresholds, since the thin fibers rarefaction was homogeneously intense in all patients, regardless of the degree of sensory deficit. We believe that the homogeneously intense denervation in leprosy lesions should be objective of further investigations focused on its

Protection of the skin against occupational and operational ultraviolet and thermal radiation

International Nuclear Information System (INIS)

Wiskemann, A.

1980-01-01

When irradiation with short wave ultraviolet (UVB) exceed the threshold doses, the eye as well as the skin react with an acute inflammation. After chronic exposure to both radiations the skin is altered as a farmers skin. Thermal visible and infrared radiation may produce a local combustion or a livedo or a general hyperthermia. Many possibilities of an occupational exposition to natural or artificial optical radiation are listed. Until now no exposure limits have been recommended in the Federal Republic of Germany. The biologic effective radiant exposure can be calculated from the spectral distribution of the irradiance. The resulting value should be clearly lower than the threshold doses for the UV-keratoconjunctivitis and for the UV-erythema of the skin. Artificial light sources have to be closed exept the useful radiation beam. When this is impossible and in case of natural radiation, the skin must be shielded by clothing and/or by sunscreen preparations. Photosensitizers as tar products have to be kept away from the skin. (orig.) 891 MG/orig. 892 HIS [de

In vitro burn model illustrating heat conduction patterns using compressed thermal papers.

Science.gov (United States)

Lee, Jun Yong; Jung, Sung-No; Kwon, Ho

2015-01-01

To date, heat conduction from heat sources to tissue has been estimated by complex mathematical modeling. In the present study, we developed an intuitive in vitro skin burn model that illustrates heat conduction patterns inside the skin. This was composed of tightly compressed thermal papers with compression frames. Heat flow through the model left a trace by changing the color of thermal papers. These were digitized and three-dimensionally reconstituted to reproduce the heat conduction patterns in the skin. For standardization, we validated K91HG-CE thermal paper using a printout test and bivariate correlation analysis. We measured the papers' physical properties and calculated the estimated depth of heat conduction using Fourier's equation. Through contact burns of 5, 10, 15, 20, and 30 seconds on porcine skin and our burn model using a heated brass comb, and comparing the burn wound and heat conduction trace, we validated our model. The heat conduction pattern correlation analysis (intraclass correlation coefficient: 0.846, p < 0.001) and the heat conduction depth correlation analysis (intraclass correlation coefficient: 0.93, p < 0.001) showed statistically significant high correlations between the porcine burn wound and our model. Our model showed good correlation with porcine skin burn injury and replicated its heat conduction patterns. © 2014 by the Wound Healing Society.

Sub?40?fs, 1060?nm Yb?fiber laser enhances penetration depth in nonlinear optical microscopy of human skin

OpenAIRE

Balu, Mihaela; Saytashev, Ilyas; Hou, Jue; Dantus, Marcos; Tromberg, Bruce J.

2015-01-01

© 2015 The Authors. Advancing the practical utility of nonlinear optical microscopy requires continued improvement in imaging depth and contrast. We evaluated second-harmonic generation (SHG) and third-harmonic generation images from ex vivo human skin and showed that a sub-40 fs, 1060-nm Yb-fiber laser can enhance SHG penetration depth by up to 80% compared to a > 100 fs, 800 nm Ti:sapphire source. These results demonstrate the potential of fiber-based laser systems to address a key perform...

Comparison of fabric skins for the simulation of sweating on thermal manikins

Science.gov (United States)

Koelblen, Barbara; Psikuta, Agnes; Bogdan, Anna; Annaheim, Simon; Rossi, René M.

2017-09-01

Sweating is an important thermoregulatory process helping to dissipate heat and, thus, to prevent overheating of the human body. Simulations of human thermo-physiological responses in hot conditions or during exercising are helpful for assessing heat stress; however, realistic sweating simulation and evaporative cooling is needed. To this end, thermal manikins dressed with a tight fabric skin can be used, and the properties of this skin should help human-like sweat evaporation simulation. Four fabrics, i.e., cotton with elastane, polyester, polyamide with elastane, and a skin provided by a manikin manufacturer (Thermetrics) were compared in this study. The moisture management properties of the fabrics have been investigated in basic tests with regard to all phases of sweating relevant for simulating human thermo-physiological responses, namely, onset of sweating, fully developed sweating, and drying. The suitability of the fabrics for standard tests, such as clothing evaporative resistance measurements, was evaluated based on tests corresponding to the middle phase of sweating. Simulations with a head manikin coupled to a thermo-physiological model were performed to evaluate the overall performance of the skins. The results of the study showed that three out of four evaluated fabrics have adequate moisture management properties with regard to the simulation of sweating, which was confirmed in the coupled simulation with the head manikin. The presented tests are helpful for comparing the efficiency of different fabrics to simulate sweat-induced evaporative cooling on thermal manikins.

FEM modeling and histological analyses on thermal damage induced in facial skin resurfacing procedure with different CO2 laser pulse duration

Science.gov (United States)

Rossi, Francesca; Zingoni, Tiziano; Di Cicco, Emiliano; Manetti, Leonardo; Pini, Roberto; Fortuna, Damiano

2011-07-01

Laser light is nowadays routinely used in the aesthetic treatments of facial skin, such as in laser rejuvenation, scar removal etc. The induced thermal damage may be varied by setting different laser parameters, in order to obtain a particular aesthetic result. In this work, it is proposed a theoretical study on the induced thermal damage in the deep tissue, by considering different laser pulse duration. The study is based on the Finite Element Method (FEM): a bidimensional model of the facial skin is depicted in axial symmetry, considering the different skin structures and their different optical and thermal parameters; the conversion of laser light into thermal energy is modeled by the bio-heat equation. The light source is a CO2 laser, with different pulse durations. The model enabled to study the thermal damage induced into the skin, by calculating the Arrhenius integral. The post-processing results enabled to study in space and time the temperature dynamics induced in the facial skin, to study the eventual cumulative effects of subsequent laser pulses and to optimize the procedure for applications in dermatological surgery. The calculated data where then validated in an experimental measurement session, performed in a sheep animal model. Histological analyses were performed on the treated tissues, evidencing the spatial distribution and the entity of the thermal damage in the collageneous tissue. Modeling and experimental results were in good agreement, and they were used to design a new optimized laser based skin resurfacing procedure.

Interaction of 1.319 μm laser with skin: an optical-thermal-damage model and experimental validation

Science.gov (United States)

Jiao, Luguang; Yang, Zaifu; Wang, Jiarui

2014-09-01

With the widespread use of high-power laser systems operating within the wavelength region of approximately 1.3 to 1.4 μm, it becomes very necessary to refine the laser safety guidelines setting the exposure limits for the eye and skin. In this paper, an optical-thermal-damage model was developed to simulate laser propagation, energy deposition, heat transfer and thermal damage in the skin for 1.319 μm laser irradiation. Meanwhile, an experiment was also conducted in vitro to measure the tempreture history of a porcine skin specimen irradiated by a 1.319 μm laser. Predictions from the model included light distribution in the skin, temperature response and thermal damge level of the tissue. It was shown that the light distribution region was much larger than that of the incident laser at the wavelength of 1.319 μm, and the maximum value of the fluence rate located on the interior region of the skin, not on the surface. By comparing the calculated temperature curve with the experimentally recorded temperautre data, good agreement was shown betweeen them, which validated the numerical model. The model also indicated that the damage integral changed little when the temperature of skin tissue was lower than about 55 °C, after that, the integral increased rapidly and denatunation of the tissue would occur. Based on this model, we can further explore the damage mechanisms and trends for the skin and eye within the wavelength region of 1.3 μm to 1.4 μm, incorporating with in vivo experimental investigations.

Comparative study of acute lateral skin damage during radio wave and laser exposure

Directory of Open Access Journals (Sweden)

Dubensky V.V.

2017-09-01

Full Text Available The purpose was to study the depth and nature of the zones of thermal damage to the skin under radio wave and laser skin dissection during experiment. Material and Methods. The model of acute thermal damage was full-liner skin wounds of 20 nonlinear rats that were divided into 2 groups and operated by different methods. In the 1st group, the incisions were made by the apparatus of radio wave surgery (Surgitron DF S5, in the 2nd group the animals were operated with a laser surgical apparatus. The magnitude and structure of the lateral thermal damage was evaluated when analyzing the biopsy material. Results. During the study of experimental wounds, the extent of carbonation in the first group (operated with Surgitron DF S5 was 11.56±3.056 urn, coagulation necrosis 116.5±26.78 urn, and the hyper-thermiazone 148.42±60.171 urn. In the group of animals operated with a laser apparatus, the carbonization zone was 22.58±6.62 urn, the coagulation necrosis zone was 331.1±79.08 urn, and the hyperthermia extent was 376.2±53.27 urn. Conclusion. A comparative study of lateral skin damage in radio wave and laser skin dissection revealed a deeper thermal change in the skin and an increase in the extent of thermally altered structures under laser action: the carbonization zone was larger than for radio waves by 11.02 urn, coagulation necrosis by 214.6 urn, and the hyperthermia zone by 227.78 urn.

Electromagnetic and thermal history during microwave heating

International Nuclear Information System (INIS)

Santos, T.; Valente, M.A.; Monteiro, J.; Sousa, J.; Costa, L.C.

2011-01-01

In microwave heating, the energy is directly introduced into the material resulting in a rapid and volumetric heating process with reduced thermal gradients, when the electromagnetic field is homogeneous. From those reasons, the microwave technology has been widely used in the industry to process dielectric materials. The capacity to heat with microwave radiation is related with the dielectric properties of the materials and the electromagnetic field distribution. The knowledge of the permittivity dependence with the temperature is essential to understand the thermal distribution and to minimize the non-homogeneity of the electromagnetic field. To analyse the history of the heating process, the evolution of the electromagnetic field, the temperature and the skin depth, were simulated dynamically in a ceramic sample. The evaluation of the thermal runaway has also been made. This is the most critical phenomenon observed in the sintering of ceramic materials because it causes deformations, or even melting on certain points in the material, originating the destruction of it. In our study we show that during the heating process the hot spot's have some dynamic, and at high temperatures most of the microwave energy is absorbed at the surface of the material. We also show the existence of a time-delay of the thermal response with the electromagnetic changes. - Highlights: → Electromagnetic field, the temperature and the skin depth were simulated dynamically. → The evaluation of the thermal runaway has been made. → A time-delay of the thermal response with the electromagnetic changes exists.

A new laser Doppler flowmeter prototype for depth dependent monitoring of skin microcirculation

Science.gov (United States)

Figueiras, E.; Campos, R.; Semedo, S.; Oliveira, R.; Requicha Ferreira, L. F.; Humeau-Heurtier, A.

2012-03-01

Laser Doppler flowmetry (LDF) is now commonly used in clinical research to monitor microvascular blood flow. However, the dependence of the LDF signal on the microvascular architecture is still unknown. That is why we propose a new laser Doppler flowmeter for depth dependent monitoring of skin microvascular perfusion. This new laser Doppler flowmeter combines for the first time, in a device, several wavelengths and different spaced detection optical fibres. The calibration of the new apparatus is herein presented together with in vivo validation. Two in vivo validation tests are performed. In the first test, signals collected in the ventral side of the forearm are analyzed; in the second test, signals collected in the ventral side of the forearm are compared with signals collected in the hand palm. There are good indicators that show that different wavelengths and fibre distances probe different skin perfusion layers. However, multiple scattering may affect the results, namely the ones obtained with the larger fibre distance. To clearly understand the wavelength effect in LDF measurements, other tests have to be performed.

Laser-induced thermal coagulation enhances skin uptake of topically applied compounds

DEFF Research Database (Denmark)

Haak, C S; Hannibal, J; Paasch, U

2017-01-01

microchannels surrounded by CZ compared to channels with no CZ (CZ-20 and CZ-80>CZ-0).The thickness of CZ affected PEG distribution in skin. A thin CZ-20 favored significantly higher mean fluorescence intensities inside CZ areas compared to CZ-80 (PEG 350, 1,000, and 5,000; P ...BACKGROUND: Ablative fractional laser (AFL) generates microchannels in skin surrounded by a zone of thermally altered tissue, termed the coagulation zone (CZ). The thickness of CZ varies according to applied wavelength and laser settings. It is well-known that AFL channels facilitate uptake...... of topically applied compounds, but the importance of CZ is unknown. METHODS: Franz Cells were used to investigate skin uptake and permeation of fluorescent labeled polyethylene glycols (PEGs) with mean molecular weights (MW) of 350, 1,000, and 5,000 Da. Microchannels with CZ thicknesses ranging from 0 to 80...

Cell death induced on cell cultures and nude mouse skin by non-thermal, nanosecond-pulsed generated plasma.

Directory of Open Access Journals (Sweden)

Arnaud Duval

Full Text Available Non-thermal plasmas are gaseous mixtures of molecules, radicals, and excited species with a small proportion of ions and energetic electrons. Non-thermal plasmas can be generated with any high electro-magnetic field. We studied here the pathological effects, and in particular cell death, induced by nanosecond-pulsed high voltage generated plasmas homogeneously applied on cell cultures and nude mouse skin. In vitro, Jurkat cells and HMEC exhibited apoptosis and necrosis, in dose-dependent manner. In vivo, on nude mouse skin, cell death occurred for doses above 113 J/cm(2 for the epidermis, 281 J/cm(2 for the dermis, and 394 J/cm(2 for the hypodermis. Using electron microscopy, we characterized apoptosis for low doses and necrosis for high doses. We demonstrated that these effects were not related to thermal, photonic or pH variations, and were due to the production of free radicals. The ability of cold plasmas to generate apoptosis on cells in suspension and, without any sensitizer, on precise skin areas, opens new fields of application in dermatology for extracorporeal blood cell treatment and the eradication of superficial skin lesions.

Histamine is not released in acute thermal injury in human skin in vivo: a microdialysis study

DEFF Research Database (Denmark)

Petersen, Lars Jelstrup; Pedersen, Juri Lindy; Skov, Per Stahl

2009-01-01

BACKGROUND: Animal models have shown histamine to be released from the skin during the acute phase of a burn injury. The role of histamine during the early phase of thermal injuries in humans remains unclear. PURPOSE: The objectives of this trial were to study histamine release in human skin during...

Skin dosimetry - radiological protection aspects of skin dosimetry

International Nuclear Information System (INIS)

Dennis, J.A.

1991-01-01

Following a Workshop in Skin Dosimetry, a summary of the radiological protection aspects is given. Aspects discussed include routine skin monitoring and dose limits, the need for careful skin dosimetry in high accidental exposures, techniques for assessing skin dose at all relevant depths and the specification of dose quantities to be measured by personal dosemeters and the appropriate methods to be used in their calibration. (UK)

WE-FG-202-01: Early Prediction of Radiotherapy Induced Skin Reactions Using Dynamic Infrared Imaging

Energy Technology Data Exchange (ETDEWEB)

Biswal, N [Rutgers Cancer Institute of New Jersey, New Brunswick, NJ (United States); Cifter, G [Boston, MA (United States); Sun, J [Argonne National Laboratory, Lemont, IL (United States); Sen, N; Wang, D; Diaz, A; Griem, K [Rush University Medical Center, Chicago, IL (United States); Chu, J [Rush University Medical Center, Oak Brook, IL (United States)

2016-06-15

Purpose: To predict radiotherapy induced skin reactions using dynamic infrared imaging. Methods: Thermal images were captured by our homebuilt system consisting of two flash lamps and an infrared (IR) camera. The surface temperature of the skin was first raised by ∼ 6 oC from ∼1 ms flashes. The camera then captured a series of IR images for 10 seconds. For each image, a baseline skin temperature was recorded for 0.5sec before heat impulse. The temporal temperature gradients were calculated between a reference point (immediately after the flash) and at a time point 9sec after that. Thermal effusivity, an intrinsic thermal property of a material, was calculated from the surface temperature decay of skin. We present experimental data in five patients undergoing radiation therapy, of which 2 were Head & Neck, 1 was Sarcoma and 2 were Breast cancer patients. The prescribed doses were 45 – 60 Gy in 25 – 30 fractions. Each patient was imaged before treatment and after every fifth fraction until end of the treatment course. An area on the skin, outside the radiation field, was imaged as control region. During imaging, each patient’s irradiated skins were scored based on RTOG skin morbidity scoring criteria. Results: Temperature gradient, which is the temperature recovery rate, depends on the thermal properties of underlying tissue. It was observed that, the skin temperature and temporal temperature gradient increases with delivered radiation dose and skin RTOG score. The treatment does not change effusivity of superficial skin layer, however there was a significant difference in effusivity between treated and control areas at depth of ∼ 1.5 – 1.8 mm, increases with dose. Conclusion: The higher temporal temperature gradient and effusivity from irradiated areas suggest that there is more fluid under the irradiated skin, which causes faster temperature recovery. The mentioned effects may be predictors of Moist Desquamation.

Noninvasive measurement of burn wound depth applying infrared thermal imaging (Conference Presentation)

Science.gov (United States)

Jaspers, Mariëlle E.; Maltha, Ilse M.; Klaessens, John H.; Vet, Henrica C.; Verdaasdonk, Rudolf M.; Zuijlen, Paul P.

2016-02-01

In burn wounds early discrimination between the different depths plays an important role in the treatment strategy. The remaining vasculature in the wound determines its healing potential. Non-invasive measurement tools that can identify the vascularization are therefore considered to be of high diagnostic importance. Thermography is a non-invasive technique that can accurately measure the temperature distribution over a large skin or tissue area, the temperature is a measure of the perfusion of that area. The aim of this study was to investigate the clinimetric properties (i.e. reliability and validity) of thermography for measuring burn wound depth. In a cross-sectional study with 50 burn wounds of 35 patients, the inter-observer reliability and the validity between thermography and Laser Doppler Imaging were studied. With ROC curve analyses the ΔT cut-off point for different burn wound depths were determined. The inter-observer reliability, expressed by an intra-class correlation coefficient of 0.99, was found to be excellent. In terms of validity, a ΔT cut-off point of 0.96°C (sensitivity 71%; specificity 79%) differentiates between a superficial partial-thickness and deep partial-thickness burn. A ΔT cut-off point of -0.80°C (sensitivity 70%; specificity 74%) could differentiate between a deep partial-thickness and a full-thickness burn wound. This study demonstrates that thermography is a reliable method in the assessment of burn wound depths. In addition, thermography was reasonably able to discriminate among different burn wound depths, indicating its potential use as a diagnostic tool in clinical burn practice.

Physical mechanisms of thermal-diffusivity depth-profile generation in a hardened low-alloy Mn, Si, Cr, Mo steel reconstructed by photothermal radiometry

International Nuclear Information System (INIS)

Nicolaides, Lena; Mandelis, Andreas; Beingessner, Clare J.

2001-01-01

It is well established that in hardened steels thermal-diffusivity broadly anticorrelates with microhardness, allowing thermal-wave depth profilometry to be used as a tool to measure microhardness profiles. Nevertheless, the physical mechanisms for this anticorrelation have not been well understood. In this work, the thermal-diffusivity profiles of rough, hardened industrial steels were reconstructed after the elimination of roughness effects from the experimental data. Carburizing and quenching are widely used for the heat treatment of steel components, and it is important to understand their effects on thermal-diffusivity profiles. A thorough examination of the actual mechanism by which thermal-diffusivity depth profiles are affected by first carburizing and then quenching AISI-8620 steels was performed. It was concluded that the variation of thermal diffusivity with depth is dominated by the carbon concentration profile, whereas the absolute value of the thermal diffusivity is a function of microstructure. [copyright] 2001 American Institute of Physics

Sub-40 fs, 1060-nm Yb-fiber laser enhances penetration depth in nonlinear optical microscopy of human skin

Science.gov (United States)

Balu, Mihaela; Saytashev, Ilyas; Hou, Jue; Dantus, Marcos; Tromberg, Bruce J.

2015-12-01

Advancing the practical utility of nonlinear optical microscopy requires continued improvement in imaging depth and contrast. We evaluated second-harmonic generation (SHG) and third-harmonic generation images from ex vivo human skin and showed that a sub-40 fs, 1060-nm Yb-fiber laser can enhance SHG penetration depth by up to 80% compared to a >100 fs, 800 nm Ti:sapphire source. These results demonstrate the potential of fiber-based laser systems to address a key performance limitation related to nonlinear optical microscopy (NLOM) technology while providing a low-barrier-to-access alternative to Ti:sapphire sources that could help accelerate the movement of NLOM into clinical practice.

Protective role of microRNA-29a in denatured dermis and skin fibroblast cells after thermal injury

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Jie Zhou

2016-03-01

Full Text Available Our previous study has suggested that downregulated microRNA (miR-29a in denatured dermis might be involved in burn wound healing. However, the exact role of miR-29a in healing of burn injury still remains unclear. Here, we found that expression of miR-29a was notably upregulated in denatured dermis tissues and skin fibroblast cells after thermal injury, and thereafter gradually downregulated compared with control group. By contrast, the expression of collagen, type I, alpha 2 (COL1A2 and vascular endothelial growth factor (VEGF-A were first reduced and subsequently upregulated in denatured dermis tissues and skin fibroblast cells after thermal injury. We further identified COL1A2 as a novel target of miR-29a, which is involved in type I collagen synthesis, and showed that miR-29a negatively regulated the expression level of COL1A2 in skin fibroblast cells. In addition, VEGF-A, another target gene of miR-29a, was also negatively mediated by miR-29a in skin fibroblast cells. Inhibition of miR-29a expression significantly promoted the proliferation and migration of skin fibroblast cells after thermal injury, and knockdown of COL1A2 and VEGF-A reversed the effects of miR-29a on the proliferation and migration of skin fibroblast cells. Furthermore, we found that Notch2/Jagged2 signaling was involved in miR-29a response to burn wound healing. Our findings suggest that downregulated miR-29a in denatured dermis may help burn wound healing in the later phase, probably via upregulation of COL1A2 and VEGF-A expression, which can further enhance type I collagen synthesis and angiogenesis.

Aging Depth Test of Rubber Blocks by Accelerated Thermal Oxidation Test

International Nuclear Information System (INIS)

Park, Junhee; Choun, Young-Sun; Kim, Min Kyu

2015-01-01

In this study, the accelerated thermal oxidation tests of rubber block were performed to investigate the aging depth of rubber bearing. From the tests, it was found the critical aging depth in rubber block. Also the property variation of rubber was investigated along the depth. The deterioration pattern from the aging depth tests was found from surface to inside and the critical aging depth was to be about 10 mm. The analytical model for rubber bearing with aging can be developed based on the relationship between the property variation and aging depth investigated from this study. The mechanical properties of rubber bearings were changed with time. Because the aging effect of rubber material was generally higher than that of other structure materials it is needed that the aging properties of seismically isolators should be evaluated to ensure the safety of seismically isolated nuclear power plants (NPPs) over the lifetime. NRC and ASCE required the tests of seismically isolators for investigating the aging properties. JNES also required the seismic response analysis for the seismically isolated NPPs when the properties of seismically isolators were extremely changed. If the aging properties of seismically isolators such as rubber bearings are evaluated by analysis the analytical model of seismically isolators should be developed considering aging effect of rubber material. From the previous research, it was reported that the behavior of aged rubber material mainly affected by temperature and oxidation. The material properties between surface and inside can be different by the oxidation of rubber. Therefore, the aging depth should be investigated for exactly evaluating the seismic behavior of aged rubber bearing. The aging depth of rubber baring was not influenced by the size of seismically isolators but environment condition. Therefore, the detail analysis considering aging depth was not required for NPPs with large seismically isolators. But the seismic response

Residual limb skin temperature and thermal comfort in people with amputation during activity in a cold environment.

Science.gov (United States)

Segal, Ava D; Klute, Glenn K

2016-01-01

Thermal comfort remains a common problem for people with lower-limb amputation. Both donning a prosthesis and engaging in activity at room temperature can increase residual limb skin temperature; however, the effects of activity on skin temperature and comfort in more extreme environments remain unknown. We examined residual limb skin temperatures and perceived thermal comfort (PTC; 11-point Likert scale) of participants with unilateral transtibial amputation (n = 8) who were snowshoeing in a cold environment. Residual limb skin temperature increased by 3.9°C [3.0°C to 4.7°C] (mean difference [95% confidence interval (CI)], p < 0.001) after two 30 min exercise sessions separated by a 5 min rest session. Minimal cooling (-0.2°C [-1.1°C to 0.6°C]) occurred during the rest period. Similar changes in PTC were found for the residual limb, intact limb, and whole body, with a mean scale increase of 1.6 [1.1 to 2.1] and 1.3 [0.8 to 1.8] for the first and second exercise sessions, respectively (p < 0.001). Activity in a cold environment caused similar increases in residual limb skin temperature as those found in studies conducted at room temperature. Participants with amputation perceived warming as their skin temperature increased during exercise followed by the perception of cooling during rest, despite minimal associated decreases in skin temperature.

Topical administration of Tetrasodium-Mesotetraphenyl-Porphinesulfonate (TPPS): correlations between drug penetration and depth of necrosis in skin of nude mice following red light irradiation

International Nuclear Information System (INIS)

Marchesini, R.; Melloni, E.; Fava, G.

1987-01-01

The main side effect in photodynamic therapy is photosensitization of the patient's skin following systemic administration of the photosensitizing agent. In the case of superficial lesions, this problem can be avoided by topically applying the drug: in this way a local treatment can be performed. The photosensitizing properties of a 2% solution of TPPS (Tetrasodium-Tetraphenylpophinesulfonate) in a vehicle containing a penetration enhancer, Azone, on skin of nude mice has been tested. An aliquot of 0.1 ml/cm 2 of the solution was painted on the skin overlying an s.c. implanted NMU-1 tumor. Subsequently, animals were sacrificed at different times after applications. Fluorescence microscopy revealed that TPPS penetration depth was related to time elapsed after application and to painting modalities. Solution penetration was enhanced by wiping with ether immediately before painting. Irradiation at 80 mW/cm 2 for 20 min with a dye laser emitting at 640 nm, 4 h after TPPS applications, produced necrosis of the upper skin layers, up to 0.2 mm in depth. These findings suggest that topical TPPS administration, followed by laser irradiation, may be a suitable treatment modality for skin lesions involving epithelial layers, even though several aspects of this methodology need further investigation

Thermal status of saturation divers during operational dives in the North Sea

Energy Technology Data Exchange (ETDEWEB)

Mekjavic, I.B.; Golden, F.St.C.; Eglin, C.M.; Tipton, M.J.

1999-08-01

This report summarises the findings of a study investigating the body temperature responses of divers at different depths, seasons, and locations in order to evaluated the effectiveness of current equipment and diving procedures and especially that of the thermal protection to maintain the safety of the diver. Details of the thermal monitoring system and the field study examining diving suit microclimate temperature, skin temperature, core temperature, thermal comfort, and fluid balance are outlined, and recommendations are given.

Forty-Year Follow-up of Full-Thickness Skin Graft After Thermal Burn Injury to the Volar Hand.

Science.gov (United States)

Weeks, Dexter; Kasdan, Morton L; Wilhelmi, Bradon J

2016-01-01

The hands are commonly affected in severe thermal burn injuries. Resulting contractures lead to significant loss of function. Burn contracture release and skin grafting are necessary to restore hand function. We report a case in which surgical reconstruction of a volar hand burn was performed with full-thickness skin grafting. The patient had a 40-year follow-up to assess the function and cosmesis of the repaired hand. We report a case in which a 15-month-old boy presented after receiving third-degree burns to the left volar hand, including the flexural aspects of the index, long, and ring fingers by placing it on a hot kitchen stove burner. The patient subsequently underwent scar contracture release and full-thickness skin grafting. Eleven years after reconstruction, further contractures developed associated with the patient's growth, which were reconstructed with repeat full-thickness skin graft from the inguinal region. No recurrence was witnessed afterward and 40 years after initial injury, the patient maintains full activities of daily living and use of his hand in his occupation. There is debate regarding the superiority of split-thickness versus full-thickness grafts during reconstruction. Our case strengthens the argument for durability of a full-thickness skin graft following thermal burn injury.

Predication of skin temperature and thermal comfort under two-way transient environments.

Science.gov (United States)

Zhou, Xin; Xiong, Jing; Lian, Zhiwei

2017-12-01

In this study, three transient environmental conditions consisting of one high-temperature phase within two low-temperature phases were developed, thus creating a temperature rise followed by a temperature fall. Twenty-four subjects (including 12 males and 12 females) were recruited and they underwent all three test scenarios. Skin temperature on seven body parts were measured during the whole period of the experiment. Besides, thermal sensation was investigated at specific moments by questionnaires. Thermal sensation models including PMV model, Fiala model and the Chinese model were applied to predict subjects' thermal sensation with comparisons carried out among them. Results show that most predicated thermal sensation by Chinese model lies within the range of 0.5 scale of the observed sensation vote, and it agrees best with the observed thermal sensation in transient thermal environment than PMV and Fiala model. Further studies should be carried out to improve performance of Chinese model for temperature alterations between "very hot" to "hot" environment, for prediction error in the temperature-fall situation of C5 (37-32°C) was over 0.5 scale. Copyright © 2017 Elsevier Ltd. All rights reserved.

Noninvasive radio frequency for skin tightening and body contouring.

Science.gov (United States)

Weiss, Robert A

2013-03-01

The medical use of radio frequency (RF) is based on an oscillating electrical current forcing collisions between charged molecules and ions, which are then transformed into heat. RF heating occurs irrespective of chromophore or skin type and is not dependent on selective photothermolysis. RF can be delivered using monopolar, bipolar, and unipolar devices, and each method has theoretical limits of depth penetration. A variant of bipolar delivery is fractional RF delivery. In monopolar configurations, RF will penetrate deeply and return via a grounding electrode. Multiple devices are available and are detailed later in the text. RF thermal stimulation is believed to result in a microinflammatory process that promotes new collagen. By manipulating skin cooling, RF can also be used for heating and reduction of fat. Currently, the most common uses of RF-based devices are to noninvasively manage and treat skin tightening of lax skin (including sagging jowls, abdomen, thighs, and arms), as well as wrinkle reduction, cellulite improvement, and body contouring.

Skin contamination dosimeter

Science.gov (United States)

Hamby, David M [Corvallis, OR; Farsoni, Abdollah T [Corvallis, OR; Cazalas, Edward [Corvallis, OR

2011-06-21

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.

Comparison of thermal and hemodynamic responses in skin and muscles to heating with electric and magnetic field

Directory of Open Access Journals (Sweden)

Karmen Glažar

2015-06-01

Full Text Available 12.00 Introduction: It has been shown that sufficient amount of energy provided by electromagnetic diathermy induces the increase of skin temperature and underlying tissues. However, scarce information is available on the differences in responses initiated by various techniques of diathermy. The goal of the present study was to compare thermal and hemodynamic responses of the skin and underlying muscles of the forearm to diathermy applied with electric (EF or magnetic field (MF. Methods: Eleven healthy volunteers participated in the study. On two separate occasions, they randomly received 20-minut diathermy with EF or with MF. Skin and tympanic temperature, and heart rate were measured. Further, kinetics of muscle oxyhemoglobin and deoxyhemoglobin kinetics were obtained. Thermal perception and thermal comfort were noted through the application of EF and MF. Results: The skin temperature increased similarly during the administration of EF and MF, by ~ 8.0 ± 1.3°C on both occasions. The thermal perception was more intense during the application of EF. Accordingly, the thermal comfort during the application of EF was perceived as less comfortable as compared with MF. During MF the increase in minute muscle blood flow and oxygen consumption was for ~ 42 % higher compared to the heating with EF. Conclusion: Although the increase in skin temperature was similar between EF and MF, the application of diathermy with MF was perceived more comfortable by the participants. Furthermore, the increase in minute muscle blood flow and oxygen consumption was higher in MF compared with EF. Thus, when muscle is the target tissue for physical therapy, a diathermy with magnetic field is the technique of choice. Normal 0 21 false false false SL X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Navadna tabela"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso

Effects of pressure, cold and gloves on hand skin temperature and manual performance of divers.

Science.gov (United States)

Zander, Joanna; Morrison, James

2008-09-01

Cold water immersion and protective gloves are associated with decreased manual performance. Although neoprene gloves slow hand cooling, there is little information on whether they provide sufficient protection when diving in cold water. Nine divers wearing three-fingered neoprene gloves and dry suits were immersed in water at 25 and 4 degrees C, at depths of 0.4 msw (101 kPa altitude adjusted) and 40 msw (497 kPa) in a hyperbaric chamber. Skin temperatures were measured at the fingers, hand, forearm, chest and head. Grip strength, tactile sensitivity and manual dexterity were measured at three time intervals. There was an exponential decay in finger and back of hand skin temperatures with exposure time in 4 degrees C water. Finger and back of hand skin temperatures were lower at 40 msw than at 0.4 msw (P effect of pressure or temperature on grip strength. Tactile sensitivity decreased linearly with finger skin temperature at both pressures. Manual dexterity was not affected by finger skin temperature at 0.4 msw, but decreased with fall in finger skin temperature at 40 msw. Results show that neoprene gloves do not provide adequate thermal protection in 4 degrees C water and that impairment of manual performance is dependent on the type of task, depth and exposure time.

Thermal Performance of Ventilated Double Skin Façades with Venetian Blinds

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Jordi Parra

2015-05-01

Full Text Available Venetian blinds (VB are shading devices of widespread use in residential and corporate buildings. They can reflect or transmit light into buildings and at the same time allow daylighting and exterior views. They can also efficiently block radiative heat from entering the building, and if combined with a heat dissipation system such as forced ventilation, they can improve the thermal performance of double skin façades (DSF. Computational Fluid Dynamics (CFD has proven to be a useful tool for modeling flow and heat transfer in DSF, including conduction, convection and radiation heat transfer phenomena. The aim of this work is to evaluate, by means of CFD, the influence of several optical, construction and operation parameters of a DSF (such as optical properties of the materials, geometrical relations of the VB or flow stream conditions in terms of energy savings, measured as a reduction of the solar load entering the building. Results obtained show that parameters such as the proximity of the VB to the exterior skin of the façade or a differentiated surface treatment for the exterior and interior faces of the VB louvers can notably affect the thermal performance of the DSF and hence the heat gains experienced by the building.

Experimental Observation of the Stratified Electrothermal Instability on Aluminum with Thickness Greater than a Skin Depth

Energy Technology Data Exchange (ETDEWEB)

Hutchinson, Trevor M. [Univ. of Nevada, Reno, NV (United States); Hutchinson, Trevor M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Awe, Thomas James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Bruno S. [Univ. of Nevada, Reno, NV (United States); Yates, Kevin [Univ. of New Mexico, Albuquerque, NM (United States); Yu, Edmund p. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yelton, William G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fuelling, Stephan [Univ. of Nevada, Reno, NV (United States)

2017-07-01

The first direct observation of the stratified electrothermal instability on the surface of thick metal is reported. Aluminum rods coated with 70 μm Parylene-N were driven to 1 MA in approximately 100 ns, with the metal thicker than the skin depth. The dielectric coating suppressed plasma formation, enabling persistent observation of discrete azimuthally-correlated stratified structures perpendicular to the current. Strata amplitudes grow rapidly, while their Fourier spectrum shifts toward longer wavelength. Assuming blackbody emission, radiometric calculations indicate strata are temperature perturbations that grow exponentially with rate γ = 0.04 ns -1 in 3000- 10,000 K aluminum.

BLEPHAROPLASTY AND PERIOCULAR SKIN RESURFACING WITH NEW GENERATION ER:YAG LASER

Directory of Open Access Journals (Sweden)

Brigita Drnovšek-Olup

2002-12-01

Full Text Available Background. In this study, a new type of Er:YAG laser, emitting irradiation with variable pulse duration, has been used for blepharoplasty and skin resurfacing in periocular region.More than 40 patients have been treated with second generation Er:YAG laser (Fotona Fidelis for blepharoplasty and skin resurfacing. A focused laser beam (diameter 0.4 mm with very short pulse width (100 µs, that is significantly below the thermal relaxation time of skin, leads to a precise cut with no observable thermal effect on surrounding tissue. The depth of the cut is approximately 1–2 mm, precision comparable to a surgical scalpel. The high repetition rate of consecutive laser pulses (50 Hz at 120 mJ energy accounts for accumulation of thermal load in tissue, and thus leads to complete hemostasis of the cut tissue. Due to improved cutting abilities of the Er:YAG laser, excision of orbital fat is also performed with one pass of the laser beam. By changing the laser parameters to short pulses (300 µs, energy 500 mJ, spot diameter 5 mm and repetition rate 12–15 Hz, skin resurfacing was performed. No special pretreatment therapy was used. Anesthesia: 2% Xylocain inj. subcutaneously. Non adhesive dressing for 24 hours was applied after surgery.Epithelisation was complete after ten days. Redness persists up to 5 weeks. Discomfort of patients was mild. Cosmetic results are satisfying.Conclusions. New generation of Er:YAG laser offers a possibility to cut and coagulate the tissue simultaneously, and by changing the parameters to ablate the tissue with heating influence on skin collagen.

Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in the build-up region of therapeutic photon beams

International Nuclear Information System (INIS)

Kim, K. A.; Yoo, W. J.; Jang, K. W.; Moon, J.; Han, K. T.; Jeon, D.; Park, J. Y.; Cha, E. J.; Lee, B.

2013-01-01

In this study, a fibre-optic dosemeter (FOD) using an organic scintillator with a diameter of 0.5 mm for photon-beam therapy dosimetry was fabricated. The fabricated dosemeter has many advantages, including water equivalence, high spatial resolution, remote sensing and real-time measurement. The scintillating light generated from an organic-dosemeter probe embedded in a solid-water stack phantom is guided to a photomultiplier tube and an electrometer via 20 m of plastic optical fibre. Using this FOD, the skin dose and the percentage depth dose in the build-up region according to the depths of a solid-water stack phantom are measured with 6- and 15-MV photon-beam energies with field sizes of 10310 and 20320 cm 2 , respectively. The results are compared with those measured using conventional dosimetry films. It is expected that the proposed FOD can be effectively used in radiotherapy dosimetry for accurate measurement of the skin dose and the depth dose distribution in the build-up region due to its high spatial resolution. (authors)

Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling

Directory of Open Access Journals (Sweden)

D. Mottaghy

2013-01-01

Full Text Available This study focuses on the temperature field observed in boreholes drilled as part of interdisciplinary scientific campaign targeting the El'gygytgyn Crater Lake in NE Russia. Temperature data are available from two sites: the lake borehole 5011-1 located near the center of the lake reaching 400 m depth, and the land borehole 5011-3 at the rim of the lake, with a depth of 140 m. Constraints on permafrost depth and past climate changes are derived from numerical simulation of the thermal regime associated with the lake-related talik structure. The thermal properties of the subsurface needed for these simulations are based on laboratory measurements of representative cores from the quaternary sediments and the underlying impact-affected rock, complemented by further information from geophysical logs and data from published literature. The temperature observations in the lake borehole 5011-1 are dominated by thermal perturbations related to the drilling process, and thus only give reliable values for the lowermost value in the borehole. Undisturbed temperature data recorded over more than two years are available in the 140 m deep land-based borehole 5011-3. The analysis of these observations allows determination of not only the recent mean annual ground surface temperature, but also the ground surface temperature history, though with large uncertainties. Although the depth of this borehole is by far too insufficient for a complete reconstruction of past temperatures back to the Last Glacial Maximum, it still affects the thermal regime, and thus permafrost depth. This effect is constrained by numerical modeling: assuming that the lake borehole observations are hardly influenced by the past changes in surface air temperature, an estimate of steady-state conditions is possible, leading to a meaningful value of 14 ± 5 K for the post-glacial warming. The strong curvature of the temperature data in shallower depths around 60 m can be explained by a

Quantification of change in vocal fold tissue stiffness relative to depth of artificial damage.

Science.gov (United States)

Rohlfs, Anna-Katharina; Schmolke, Sebastian; Clauditz, Till; Hess, Markus; Müller, Frank; Püschel, Klaus; Roemer, Frank W; Schumacher, Udo; Goodyer, Eric

2017-10-01

To quantify changes in the biomechanical properties of human excised vocal folds with defined artificial damage. The linear skin rheometer (LSR) was used to obtain a series of rheological measurements of shear modulus from the surface of 30 human cadaver vocal folds. The tissue samples were initially measured in a native condition and then following varying intensities of thermal damage. Histological examination of each vocal fold was used to determine the depth of artificial alteration. The measured changes in stiffness were correlated with the depth of cell damage. For vocal folds in a pre-damage state the shear modulus values ranged from 537 Pa to 1,651 Pa (female) and from 583 Pa to 1,193 Pa (male). With increasing depth of damage from the intermediate layer of the lamina propria (LP), tissue stiffness increased consistently (compared with native values) following application of thermal damage to the vocal folds. The measurement showed an increase of tissue stiffness when the depth of tissue damage was extending from the intermediate LP layer downwards. Changes in the elastic characteristics of human vocal fold tissue following damage at defined depths were demonstrated in an in vitro experiment. In future, reproducible in vivo measurements of elastic vocal fold tissue alterations may enable phonosurgeons to infer the extent of subepithelial damage from changes in surface elasticity.

Model Predictions and Measured Skin Damage Thresholds for 1.54 Micrometers Laser Pulses in Porcine Skin

National Research Council Canada - National Science Library

Roach, William P; Cain, Clarence; Schuster, Kurt; Stockton, Kevin; Stolarski, David S; Galloway, Robert; Rockwell, Benjamin

2004-01-01

A new source-term thermal model was used to determine the skin temperature rise using porcine skin parameters for various wavelengths, pulse durations, and laser spot sizes and is compared to the Takata thermal model...

Curative effects of microneedle fractional radiofrequency system on skin laxity in Asian patients: A prospective, double-blind, randomized, controlled face-split study.

Science.gov (United States)

Lu, Wenli; Wu, Pinru; Zhang, Zhen; Chen, Jinan; Chen, Xiangdong; Ewelina, Biskup

2017-04-01

To date, no studies compared curative effects of thermal lesions in deep and superficial dermal layers in the same patient (face-split study). To evaluate skin laxity effects of microneedle fractional radiofrequency induced thermal lesions in different dermal layers. 13 patients underwent three sessions of a randomized face-split microneedle fractional radiofrequency system (MFRS) treatment of deep dermal and superficial dermal layer. Skin laxity changes were evaluated objectively (digital images, 2 independent experts) and subjectively (patients' satisfaction numerical rating). 12 of 13 subjects completed a course of 3 treatments and a 1-year follow-up. Improvement of nasolabial folds in deep dermal approach was significantly better than that in superficial approach at three months (P=.0002) and 12 months (P=.0057) follow-up. Effects on infraorbital rhytides were only slightly better (P=.3531). MFRS is an effective method to improve skin laxity. Thermal lesion approach seems to provide better outcomes when applied to deep dermal layers. It is necessary to consider the skin thickness of different facial regions when choosing the treatment depth.

Photothermal Radiometry for Skin Research

Directory of Open Access Journals (Sweden)

Perry Xiao

2016-02-01

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.

Depth of the graft bed influences split-skin graft contraction.

NARCIS (Netherlands)

Mensik, I.; Lamme, E.N.; Brychta, P.

2003-01-01

Contraction of a split-thickness skin graft used for coverage of large defects remains a great problem in plastic, burn and reconstructive surgery. In this study we evaluated healing of split-thickness skin grafts transplanted in wounds on the subcutaneous fat and muscle fascia in pigs. Four young

Simulation study of the thermal and the thermoelastic effects induced by pulsed laser absorption in human skin

Science.gov (United States)

Kim, Jae-Young; Jang, Kyungmin; Yang, Seung-Jin; Baek, Jun-Hyeok; Park, Jong-Rak; Yeom, Dong-Il; Kim, Ji-Sun; Kim, Hyung-Sik; Jun, Jae-Hoon; Chung, Soon-Cheol

2016-04-01

We studied the thermal and the mechanical effects induced by pulsed laser absorption in human skin by numerically solving the heat-transfer and the thermoelastic wave equations. The simulation of the heat-transfer equation yielded the spatiotemporal distribution of the temperature increase in the skin, which was then used in the driving term of the thermoelastic wave equation. We compared our simulation results for the temperature increase and the skin displacements with the measured and numerical results, respectively. For the comparison, we used a recent report by Jun et al. [Sci. Rep. 5, 11016 (2015)], who measured in vivo skin temperature and performed numerical simulation of the thermoelastic wave equation using a simple assumption about the temporal evolution of the temperature distribution, and found their results to be in good agreement with our results. In addition, we obtained solutions for the stresses in the human skin and analyzed their dynamic behaviors in detail.

Biothermomechanical behavior of skin tissue

Institute of Scientific and Technical Information of China (English)

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

2008-01-01

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.

Skin Microbiome in Patients With Psoriasis Before and After Balneotherapy at the Thermal Care Center of La Roche-Posay.

Science.gov (United States)

Martin, Richard; Henley, Jessica B; Sarrazin, Patrick; Seité, Sophie

2015-12-01

Changes in the composition of microbial communities that colonize skin have been linked to several diseases including psoriasis. Nevertheless, the intra-individual dynamics and how these communities respond to balneotherapy remain poorly understood. This open label study was conducted between July and September 2012. Microbial communities of patients with psoriasis vulgaris were characterized prior and post a 3-week selenium-rich water balneotherapy treatment at the thermal care center La Roche-Posay (La Roche-Posay, France). Balneotherapy consisted of high-pressure filiform showers, baths, facial, and body spray treatments as well as La Roche-Posay thermal spring water (LRP-TSW) consumption. Swabs were taken from affected and proximal unaffected skin and the 16S rRNA bacterial gene was used to analyze the composition of bacterial communities. Using the same 16S rRNA gene tool, we tried to describe the LRP-TSW bacterial landscape. This study included 54 patients diagnosed with moderate to severe forms of psoriasis vulgaris. After eliminating individuals lacking paired samples from both visits, 29 individuals were analyzed for their microbiome profile. Shannon Diversity Index and global bacterial landscape indicate similar microbial communities on both unaffected and adjacent affected skin. PASI values decreased post-balneotherapy implying improvement of disease severity. No significant change in the Shannon Diversity Index was noticed at the end of the third week. The average taxonomic composition of skin microbial communities associated with unaffected and affected skin of psoriatic patients post-balneotherapy shows that treatment with LRP-TSW significantly increased the level of Xanthomonas genus and, to a lesser extent, Corynebacterium genus. The Xanthomonas genus belongs to the main Xanthomonadaceae family found in LRP-TSW and also on healthy skin. In psoriatic patients, a poor bacterial biodiversity was noticed and the bacterial communities were similar on

Numerical evaluation and optimization of depth-oriented temperature measurements for the investigation of thermal influences on groundwater

Science.gov (United States)

Köhler, Mandy; Haendel, Falk; Epting, Jannis; Binder, Martin; Müller, Matthias; Huggenberger, Peter; Liedl, Rudolf

2015-04-01

Increasing groundwater temperatures have been observed in many urban areas such as London (UK), Tokyo (Japan) and also in Basel (Switzerland). Elevated groundwater temperatures are a result of different direct and indirect thermal impacts. Groundwater heat pumps, building structures located within the groundwater and district heating pipes, among others, can be addressed to direct impacts, whereas indirect impacts result from the change in climate in urban regions (i.e. reduced wind, diffuse heat sources). A better understanding of the thermal processes within the subsurface is urgently needed for decision makers as a basis for the selection of appropriate measures to reduce the ongoing increase of groundwater temperatures. However, often only limited temperature data is available that derives from measurements in conventional boreholes, which differ in construction and instrumental setup resulting in measurements that are often biased and not comparable. For three locations in the City of Basel models were implemented to study selected thermal processes and to investigate if heat-transport models can reproduce thermal measurements. Therefore, and to overcome the limitations of conventional borehole measurements, high-resolution depth-oriented temperature measurement systems have been introduced in the urban area of Basel. In total seven devices were installed with up to 16 sensors which are located in the unsaturated and saturated zone (0.5 to 1 m separation distance). Measurements were performed over a period of 4 years (ongoing) and provide sufficient data to set up and calibrate high-resolution local numerical heat transport models which allow studying selected local thermal processes. In a first setup two- and three-dimensional models were created to evaluate the impact of the atmosphere boundary on groundwater temperatures (see EGU Poster EGU2013-9230: Modelling Strategies for the Thermal Management of Shallow Rural and Urban Groundwater bodies). For Basel

Photoacoustic detection of neovascularities in skin graft

Science.gov (United States)

Yamazaki, Mutsuo; Sato, Shunichi; Saitoh, Daizo; Ishihara, Miya; Okada, Yoshiaki; Ashida, Hiroshi; Obara, Minoru

2005-04-01

We previously proposed a new method for monitoring adhesion of skin graft by measuring photoacoustic (PA) signal originated from the neovascularities. In this study, immunohistochemical staining (IHC) with CD31 antibody was performed for grafted skin tissue to observe neovascularity, and the results were compared with PA signals. We also used a laser Doppler imaging (LDI) to observe blood flow in the grafted skin, and sensitivity of PA measurement and that of LDI were compared. In rat autograft models, PA signals were measured for the grafted skin at postgrafting times of 0-48 h. At 6 h postgrafting, PA signal was observed in the skin depth region of 500-600 mm, while the results of IHC showed that angiogenesis occurred at the depth of about 600 mm. Depths at which PA signal and angiogenesis were observed decreased with postgrafting time. These indicate that the PA signal observed at 6 h postgrafting originated from the neovascularities in the skin graft. Results of LDI showed no blood-originated signal before 48 h postgrafting. These findings suggest that PA measurement is effective in monitoring the adhesion of skin graft in early stage after transplantation.

Thermal characterisation of gelatin extracted from yellowfin tuna skin and commercial mammalian gelatin.

Science.gov (United States)

Rahman, Mohammad Shafiur; Al-Saidi, Ghalib Said; Guizani, Nejib

2008-05-15

Glass transition and other thermal characteristics of gelatin from different sources were studied by differential scanning calorimetry (DSC) and modulated DSC (MDSC). The initial glass transition temperatures of equilibrated gelatin samples at 11.3% relative humidity, determined from reversible heat flow thermogram of MDSC, were 23, 75 and 59°C, respectively, for tuna skin, bovine and porcine gelatin. When gelatin samples were equilibrated at higher relative humidity of 52.9%, glass transition temperature of fish skin and bovine gelatin decreased to -3 and 57°C, respectively. Further increase of equilibration relative humidity to 75.3% showed increased value in the case of tuna skin, whereas bovine and porcine did not show any significant change. DSC and MDSC results indicated that tuna gelatin showed lower glass transition compared to mammalian source gelatin equilibrated at the same constant relative humidity. In general glass transition measured by DSC was found lower than the values measured by MDSC. The results in this study showed that the degree of plasticization varied with the source of gelatin as well as their extraction methods. Copyright © 2007 Elsevier Ltd. All rights reserved.

Modeling a Naturally Ventilated Double Skin Façade with a Building Thermal Simulation Program

DEFF Research Database (Denmark)

Jensen, Rasmus Lund; Kalyanova, Olena; Heiselberg, Per

2008-01-01

to predict. This is manly due to the very transient and complex air flow in the naturally ventilated double skin façade cavity. In this paper the modelling of the DSF using a thermal simulation program, BSim, is discussed. The simulations are based on the measured weather boundary conditions...

Application of a plasma-jet for skin antisepsis: analysis of the thermal action of the plasma by laser scanning microscopy

International Nuclear Information System (INIS)

Lademann, O; Kramer, A; Richter, H; Patzelt, A; Alborova, A; Humme, D; Weltmann, K-D; Hartmann, B; Hinz, P; Koch, S

2010-01-01

Recently, it was reported that a plasma-jet could be efficiently applied for the antisepsis of wounds. In this case, the discharge in an argon gas stream was used to produce a so-called ''cold plasma'' on the skin surface. The thermal action of the plasma on the skin was investigated in the present study by means of laser scanning microscopy (LSM) and by histological analysis. Consequently, the plasma beam was moved with a definite velocity at an optimal distance over the skin surface. The structural changes of the tissue were analyzed. It was found by LSM that a thermal damage could be detected only in the upper cell layers of the stratum corneum (SC) at moving velocities of the plasma beam, usually applied in clinical practice. Deeper parts of the SC were not damaged. The structural changes were so superficial that they could be detected only by LSM but not by analysis of the histological sections

Strongly anisotropic thermal conductivity and adequate breathability of bilayered films for heat management of on-skin electronics

Science.gov (United States)

Zhou, Tianle; Wei, Hao; Tan, Huaping; Wang, Xin; Zeng, Haibo; Liu, Xiaoheng; Nagao, Shijo; Koga, Hirotaka; Nogi, Masaya; Sugahara, Tohru; Suganuma, Katsuaki

2018-07-01

Thin-film wearable electronics are required to be directly laminated on to human skin for reliable, sensitive bio-sensing but with minimal irritation to the user after long-time use. Excellent heat management films with strongly anisotropic thermal conductivity (K) and adequate breathability are increasingly desirable for shielding the skin from heating while allowing the skin to breathe properly. Here, interfacial self-assembly of a graphene oxide (GO) film covering an ambient-dried bacterial cellulose aerogel (AD-BCA) film followed by laser reduction was proposed to prepare laser-reduced GO (L-rGO)/AD-BCA bilayered films. The AD-BCA substrate provides low cross-plane K (K ⊥  ≈  0.052 W mK‑1), high breathability, and high compressive and tensile resistance by ‘partially’ inheriting the pore structure from bacterial cellulose (BC) gel. The introduction of an upper L-rGO film, which is only 0.31 wt% content, dramatically increases the in-plane K (K // ) from 0.3 W mK‑1 in AD-BCA to 10.72 W mK‑1 owing to the highly in-plane oriented, continuous, uniform assembling geometry of the GO film; while K ⊥ decreases to a lower value of 0.033 W mK‑1, mainly owing to the air pockets between L-rGO multilayers caused by the laser reduction. The bilayered films achieve a K // /K ⊥ of 325, which is substantially larger even than that of graphite and similar polymer composites. They permit high transmission rates for water vapor (416.78 g/m2/day, >204 g/m2/day of normal skin) and O2 (449.35 cm3/m2/day). The combination of strongly anisotropic thermal conductivity and adequate breathability facilitates applications in heat management in on-skin electronics.

Spectra from 2.5-15 μm of tissue phantom materials, optical clearing agents and ex vivo human skin: implications for depth profiling of human skin

International Nuclear Information System (INIS)

Viator, John A; Choi, Bernard; Peavy, George M; Kimel, Sol; Nelson, J Stuart

2003-01-01

Infrared measurements have been used to profile or image biological tissue, including human skin. Usually, analysis of such measurements has assumed that infrared absorption is due to water and collagen. Such an assumption may be reasonable for soft tissue, but introduction of exogenous agents into skin or the measurement of tissue phantoms has raised the question of their infrared absorption spectrum. We used Fourier transform infrared spectroscopy in attenuated total reflection mode to measure the infrared absorption spectra, in the range of 2-15 μm, of water, polyacrylamide, Intralipid, collagen gels, four hyperosmotic clearing agents (glycerol, 1,3-butylene glycol, trimethylolpropane, Topicare TM ), and ex vivo human stratum corneum and dermis. The absorption spectra of the phantom materials were similar to that of water, although additional structure was noted in the range of 6-10 μm. The absorption spectra of the clearing agents were more complex, with molecular absorption bands dominating between 6 and 12 μm. Dermis was similar to water, with collagen structure evident in the 6-10 μm range. Stratum corneum had a significantly lower absorption than dermis due to a lower content of water. These results suggest that the assumption of water-dominated absorption in the 2.5-6 μm range is valid. At longer wavelengths, clearing agent absorption spectra differ significantly from the water spectrum. This spectral information can be used in pulsed photothermal radiometry or utilized in the interpretation of reconstructions in which a constant μ ir is used. In such cases, overestimating μ ir will underestimate chromophore depth and vice versa, although the effect is dependent on actual chromophore depth. (note)

Heat transfer through the thermal skin of a cooling pond with waves

International Nuclear Information System (INIS)

Wesely, M.L.

1979-01-01

The temperature drop measured across the cool skin of a cooling pond is examined for 64 10-min data collection periods taken with wind speeds of 3--8.5 m s -1 (effectively at a height of 10 m) and surface temperatures of 18 0 --37.5 0 C. The total heat transfer through the skin is found with the use of bulk aerodynamic estimates of the latent and sensible heat flux densities and empirical expressions for the long-wave radiation exchange at the surface. Although it is questionable to describe the characteristics of a surface with waves by use of formulae derived partially on the assumption that a rigid boundary exists at the air-water interface, the parameterizations that result seem on the average to perform quite well. For example, values of the numerical proportionally coefficient lambda [Saunders, 1967], which relates the total heat transfer to the temperature drop, increase slightly from 6 to 7 as water temperature increases; these values are near those reported previously. No variation of lambda with wind speed is detected. If lambda is replaced by a numerical coefficient that also takes into account the difference of the thicknesses of the thermal and viscous sublayers, the new coefficient Λapprox. =lambdaPr/sup 1/3/, where Pr is the Prandtl number, does not vary significantly with temperature of the surface skin

Relation between 1m depth temperature and average geothermal gradient at 75cm depth in geothermal fields

OpenAIRE

江原, 幸雄

2009-01-01

Shallow ground temperatures such as 1m depth temperature have been measured to delineate thermal anomalies of geothermal fields and also to estimate heat discharge rates from geothermal fields. As a result, a close linear relation between 1m depth temperature and average geothermal gradient at 75cm depth has been recognized in many geothermal fields and was used to estimate conductive heat discharge rates. However, such a linear relation may show that the shallow thermal regime in geothermal ...

Thermally modulated nano-trampoline material as smart skin for gas molecular mass detection

Science.gov (United States)

Xia, Hua

2012-06-01

Conventional multi-component gas analysis is based either on laser spectroscopy, laser and photoacoustic absorption at specific wavelengths, or on gas chromatography by separating the components of a gas mixture primarily due to boiling point (or vapor pressure) differences. This paper will present a new gas molecular mass detection method based on thermally modulated nano-trampoline material as smart skin for gas molecular mass detection by fiber Bragg grating-based gas sensors. Such a nanomaterial and fiber Bragg grating integrated sensing device has been designed to be operated either at high-energy level (highly thermal strained status) or at low-energy level (low thermal strained status). Thermal energy absorption of gas molecular trigs the sensing device transition from high-thermal-energy status to low-thermal- energy status. Experiment has shown that thermal energy variation due to gas molecular thermal energy absorption is dependent upon the gas molecular mass, and can be detected by fiber Bragg resonant wavelength shift with a linear function from 17 kg/kmol to 32 kg/kmol and a sensitivity of 0.025 kg/kmol for a 5 micron-thick nano-trampoline structure and fiber Bragg grating integrated gas sensing device. The laboratory and field validation data have further demonstrated its fast response characteristics and reliability to be online gas analysis instrument for measuring effective gas molecular mass from single-component gas, binary-component gas mixture, and multi-gas mixture. The potential industrial applications include fouling and surge control for gas charge centrifugal compressor ethylene production, gas purity for hydrogen-cooled generator, gasification for syngas production, gasoline/diesel and natural gas fuel quality monitoring for consumer market.

Ultrasound therapy applicators for controlled thermal modification of tissue

Science.gov (United States)

Burdette, E. Clif; Lichtenstiger, Carol; Rund, Laurie; Keralapura, Mallika; Gossett, Chad; Stahlhut, Randy; Neubauer, Paul; Komadina, Bruce; Williams, Emery; Alix, Chris; Jensen, Tor; Schook, Lawrence; Diederich, Chris J.

2011-03-01

Heat therapy has long been used for treatments in dermatology and sports medicine. The use of laser, RF, microwave, and more recently, ultrasound treatment, for psoriasis, collagen reformation, and skin tightening has gained considerable interest over the past several years. Numerous studies and commercial devices have demonstrated the efficacy of these methods for treatment of skin disorders. Despite these promising results, current systems remain highly dependent on operator skill, and cannot effectively treat effectively because there is little or no control of the size, shape, and depth of the target zone. These limitations make it extremely difficult to obtain consistent treatment results. The purpose of this study was to determine the feasibility for using acoustic energy for controlled dose delivery sufficient to produce collagen modification for the treatment of skin tissue in the dermal and sub-dermal layers. We designed and evaluated a curvilinear focused ultrasound device for treating skin disorders such as psoriasis, stimulation of wound healing, tightening of skin through shrinkage of existing collagen and stimulation of new collagen formation, and skin cancer. Design parameters were examined using acoustic pattern simulations and thermal modeling. Acute studies were performed in 201 freshly-excised samples of young porcine underbelly skin tissue and 56 in-vivo treatment areas in 60- 80 kg pigs. These were treated with ultrasound (9-11MHz) focused in the deep dermis. Dose distribution was analyzed and gross pathology assessed. Tissue shrinkage was measured based on fiducial markers and video image registration and analyzed using NIH Image-J software. Comparisons were made between RF and focused ultrasound for five energy ranges. In each experimental series, therapeutic dose levels (60degC) were attained at 2-5mm depth. Localized collagen changes ranged from 1-3% for RF versus 8-15% for focused ultrasound. Therapeutic ultrasound applied at high

Approximate relationship between frequency-dependent skin depth ...

Indian Academy of Sciences (India)

results in the absence/limited number of borehole information, which is usually limited to information on the spot. ..... 2. /MN) · Ra (7). The processed average geological resistivity and depth of .... gical formation, it gives a clue to the behaviour.

Extraordinary Magnetic Field Enhancement with Metallic Nanowire: Role of Surface Impedance in Babinet's Principle for Sub-Skin-Depth Regime

Science.gov (United States)

Koo, Sukmo; Kumar, M. Sathish; Shin, Jonghwa; Kim, Daisik; Park, Namkyoo

2009-12-01

We propose and analyze the “complementary” structure of a metallic nanogap, namely, the metallic nanowire for magnetic field enhancement. A huge enhancement of the field up to a factor of 300 was achieved. Introducing the surface impedance concept, we also develop and numerically confirm a new analytic theory which successfully predicts the field enhancement factors for metal nanostructures. Compared to the predictions of the classical Babinet principle applied to a nanogap, an order of magnitude difference in the field enhancement factor was observed for the sub-skin-depth regime nanowire.

Fractional CO2 laser resurfacing of photoaged facial and non-facial skin: histologic and clinical results and side effects.

Science.gov (United States)

Sasaki, Gordon H; Travis, Heather M; Tucker, Barbara

2009-12-01

CO(2) fractional ablation offers the potential for facial and non-facial skin resurfacing with minimal downtime and rapid recovery. The purpose of this study was (i) to document the average depths and density of adnexal structures in non-lasered facial and non-facial body skin; (ii) to determine injury in ex vivo human thigh skin with varying fractional laser modes; and (iii) to evaluate the clinical safety and efficacy of treatments. Histologies were obtained from non-lasered facial and non-facial skin from 121 patients and from 14 samples of excised lasered thigh skin. Seventy-one patients were evaluated after varying energy (mJ) and density settings by superficial ablation, deeper penetration, and combined treatment. Skin thickness and adnexal density in non-lasered skin exhibited variable ranges: epidermis (47-105 mum); papillary dermis (61-105 mum); reticular dermis (983-1986 mum); hair follicles (2-14/ HPF); sebaceous glands (2-23/HPF); sweat glands (2-7/HPF). Histological studies of samples from human thigh skin demonstrated that increased fluencies in the superficial, deep and combined mode resulted in predictable deeper levels of ablations and thermal injury. An increase in density settings results in total ablation of the epidermis. Clinical improvement of rhytids and pigmentations in facial and non-facial skin was proportional to increasing energy and density settings. Patient assessments and clinical gradings by the Wilcoxon's test of outcomes correlated with more aggressive settings. Prior knowledge of normal skin depths and adnexal densities, as well as ex vivo skin laser-injury profiles at varying fluencies and densities, improve the safety and efficiency of fractional CO(2) for photorejuvenation of facial and non-facial skin.

Analysis of erythema after Er:YAG laser skin resurfacing.

Science.gov (United States)

Ko, Na Young; Ahn, Hyo-Hyun; Kim, Soo-Nam; Kye, Young-Chul

2007-11-01

Postoperative erythema can be expected to occur in every patient after laser resurfacing, and pigmentary disturbances may be related to the intensity and the duration of erythema. This study was undertaken to assess the clinical features of erythema, the factors that influence its duration, and the relation between the duration of erythema and the incidence of hyperpigmentation and hypopigmentation in skin of Asian persons after Er:YAG laser resurfacing. A total of 218 patients (skin phototypes III to V) were recruited and treated with a short-pulsed Er:YAG laser, a variable-pulsed Er:YAG laser, or a dual-mode Er:YAG laser for skin resurfacing. Clinical assessments were performed retrospectively using medical charts and serial photographs. Postoperative erythema was observed in all patients after Er:YAG laser resurfacing with a mean duration of 4.72 months. In 98.2% of patients, erythema faded completely within 12 months. Postinflammatory hyperpigmentation was observed in 38.1% of patients after Er:YAG laser resurfacing. Skin phototype, level of ablation, and depth of thermal damage caused by a long-pulsed laser appear to be important factors that affect the duration of erythema. Moreover, prolonged erythema was related to the risk of postinflammatory hyperpigmentation.

Thermal transport across solid-solid interfaces enhanced by pre-interface isotope-phonon scattering

Science.gov (United States)

Lee, Eungkyu; Luo, Tengfei

2018-01-01

Thermal transport across solid interfaces can play critical roles in the thermal management of electronics. In this letter, we use non-equilibrium molecular dynamics simulations to investigate the isotope effect on the thermal transport across SiC/GaN interfaces. It is found that engineered isotopes (e.g., 10% 15N or 71Ga) in the GaN layer can increase the interfacial thermal conductance compared to the isotopically pure case by as much as 23%. Different isotope doping features, such as the isotope concentration, skin depth of the isotope region, and its distance from the interface, are investigated, and all of them lead to increases in thermal conductance. Studies of spectral temperatures of phonon modes indicate that interfacial thermal transport due to low-frequency phonons (transport. This work may provide insights into interfacial thermal transport and useful guidance to practical material design.

Numerical analysis for the conjugate heat transfer of skin under various temperature conditions of contrast therapy

Energy Technology Data Exchange (ETDEWEB)

Park, Da Ae; Oh, Han Nah; Choi, Hyoung Gwon [Dept. of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of); Jeon, Byoung Jin; Kim, Eun Jeoung; Lee, Seung Deok [Yonsei University, Seoul (Korea, Republic of)

2015-11-15

In this paper, the contrast therapy of skin was numerically investigated by solving the conjugate heat transfer problem. A finite volume method based on the SIMPLE algorithm was adopted to solve the axisymmetric incompressible Navier-Stokes equations, coupled with an energy equation. These equations are strongly coupled with the Pennes bio-heat equation in order to consider the effect of blood perfusion rate. We investigated the thermal response of skin at some selected depths for various input temperature profiles of a stimulator for contrast therapy. From the numerical simulations, the regions with cold/hot threshold temperatures were found for five input temperature profiles. It was shown that the temperature varies mildly for different input profiles as the depth increases, owing to the Pennes effect. The input temperatures for effective hot/cold stimulation of dermis layer were found to be 47 degrees C and 7 degrees C, respectively. The present numerical results will be used for finding an optimal temperature profile of a stimulator for contrast therapy.

Fractional laser skin resurfacing.

Science.gov (United States)

Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

2012-11-01

Laser skin resurfacing (LSR) has evolved over the past 2 decades from traditional ablative to fractional nonablative and fractional ablative resurfacing. Traditional ablative LSR was highly effective in reducing rhytides, photoaging, and acne scarring but was associated with significant side effects and complications. In contrast, nonablative LSR was very safe but failed to deliver consistent clinical improvement. Fractional LSR has achieved the middle ground; it combined the efficacy of traditional LSR with the safety of nonablative modalities. The first fractional laser was a nonablative erbium-doped yttrium aluminum garnet (Er:YAG) laser that produced microscopic columns of thermal injury in the epidermis and upper dermis. Heralding an entirely new concept of laser energy delivery, it delivered the laser beam in microarrays. It resulted in microscopic columns of treated tissue and intervening areas of untreated skin, which yielded rapid reepithelialization. Fractional delivery was quickly applied to ablative wavelengths such as carbon dioxide, Er:YAG, and yttrium scandium gallium garnet (2,790 nm), providing more significant clinical outcomes. Adjustable laser parameters, including power, pitch, dwell time, and spot density, allowed for precise determination of percent surface area, affected penetration depth, and clinical recovery time and efficacy. Fractional LSR has been a significant advance to the laser field, striking the balance between safety and efficacy.

Determination of Flaw Size and Depth From Temporal Evolution of Thermal Response

Science.gov (United States)

Winfree, William P.; Zalameda, Joseph N.; Cramer, Elliott; Howell, Patricia A.

2015-01-01

Simple methods for reducing the pulsed thermographic responses of flaws have tended to be based on either the spatial or temporal response. This independent assessment limits the accuracy of characterization. A variational approach is presented for reducing the thermographic data to produce an estimated size for a flaw that incorporates both the temporal and spatial response to improve the characterization. The size and depth are determined from both the temporal and spatial thermal response of the exterior surface above a flaw and constraints on the length of the contour surrounding the delamination. Examples of the application of the technique to simulation and experimental data acquired are presented to investigate the limitations of the technique.

Putative photoacoustic damage in skin induced by pulsed ArF excimer laser

Energy Technology Data Exchange (ETDEWEB)

Watanabe, S.; Flotte, T.J.; McAuliffe, D.J.; Jacques, S.L.

1988-05-01

Argon-fluoride excimer laser ablation of guinea pig stratum corneum causes deeper tissue damage than expected for thermal or photochemical mechanisms, suggesting that photoacoustic waves have a role in tissue damage. Laser irradiation (193 nm, 14-ns pulse) at two different radiant exposures, 62 and 156 mJ/cm2 per pulse, was used to ablate the 15-microns-thick stratum corneum of the skin. Light and electron microscopy of immediate biopsies demonstrated damage to fibroblasts as deep as 88 and 220 microns, respectively, below the ablation site. These depths are far in excess of the optical penetration depth of 193-nm light (1/e depth = 1.5 micron). The damage is unlikely to be due to a photochemical mechanism because (a) the photons will not penetrate to these depths, (b) it is a long distance for toxic photoproducts to diffuse, and (c) damage is proportional to laser pulse intensity and not the total dose that accumulates in the residual tissue; therefore, reciprocity does not hold. Damage due to a thermal mechanism is not expected because there is not sufficient energy deposited in the tissue to cause significant heating at such depths. The damage is most likely due to a photoacoustic mechanism because (a) photoacoustic waves can propagate deep into tissue, (b) the depth of damage increases with increasing laser pulse intensity rather than with increasing total residual energy, and (c) the effects are immediate. These effects should be considered in the evaluation of short pulse, high peak power laser-tissue interactions.

OCT imaging of skin cancer and other dermatological diseases

DEFF Research Database (Denmark)

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

2009-01-01

Optical coherence tomography (OCT) provides clinicians and researchers with micrometer-resolution, in vivo, cross-sectional images of human skin up to several millimeter depth. This review of OCT imaging applied within dermatology covers the application of OCT to normal skin, and reports on a lar...... number of applications in the fields of non-melanoma skin cancer, malignant melanomas, psoriasis and dermatitis, infestations, bullous skin diseases, tattoos, nails, haemangiomas, and other skin diseases. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)......Optical coherence tomography (OCT) provides clinicians and researchers with micrometer-resolution, in vivo, cross-sectional images of human skin up to several millimeter depth. This review of OCT imaging applied within dermatology covers the application of OCT to normal skin, and reports on a large...

On dependence of thermal transport on the safety factor q in tokamaks

International Nuclear Information System (INIS)

Hirose, A.; Singh, A.; Livingstone, S.; Liu, D.

2005-01-01

Mixing length estimates of the anomalous ion and electron thermal diffusivities caused by the ITG and ETG mode, respectively, have revealed that both diffusivities are proportional to the safety factor q. In the case of ITG mode, the maximum χ i occurs at long wavelengths where coupling to the ion acoustic mode is dominant while ETG driven χ e peaks at wavelengths comparable to the electron skin depth. (author)

Ingestion of an Oral Hyaluronan Solution Improves Skin Hydration, Wrinkle Reduction, Elasticity, and Skin Roughness: Results of a Clinical Study.

Science.gov (United States)

Göllner, Imke; Voss, Werner; von Hehn, Ulrike; Kammerer, Susanne

2017-10-01

Intake of oral supplements with the aim of a cutaneous antiaging effect are increasingly common. Hyaluronic acid (HA) is a promising candidate, as it is the key factor for preserving tissue hydration. In our practice study, we evaluated the effect of an oral HA preparation diluted in a cascade-fermented organic whole food concentrate supplemented with biotin, vitamin C, copper, and zinc (Regulatpro Hyaluron) on skin moisture content, elasticity, skin roughness, and wrinkle depths. Twenty female subjects with healthy skin in the age group of 45 to 60 years took the product once daily for 40 days. Different skin parameters were objectively assessed before the first intake, after 20 and after 40 days. Intake of the HA solution led to a significant increase in skin elasticity, skin hydration, and to a significant decrease in skin roughness and wrinkle depths. The supplement was well tolerated; no side effects were noted throughout the study.

Photothermal depth profiling: Comparison between genetic algorithms and thermal wave backscattering (abstract)

Science.gov (United States)

Li Voti, R.; Sibilia, C.; Bertolotti, M.

2003-01-01

Photothermal depth profiling has been the subject of many papers in the last years. Inverse problems on different kinds of materials have been identified, classified, and solved. A first classification has been done according to the type of depth profile: the physical quantity to be reconstructed is the optical absorption in the problems of type I, the thermal effusivity for type II, and both of them for type III. Another classification may be done depending on the time scale of the pump beam heating (frequency scan, time scan), or on its geometrical symmetry (one- or three-dimensional). In this work we want to discuss two different approaches, the genetic algorithms (GA) [R. Li Voti, C. Melchiorri, C. Sibilia, and M. Bertolotti, Anal. Sci. 17, 410 (2001); R. Li Voti, Proceedings, IV Int. Workshop on Advances in Signal Processing for Non-Destructive Evaluation of Materials, Quebec, August 2001] and the thermal wave backscattering (TWBS) [R. Li Voti, G. L. Liakhou, S. Paoloni, C. Sibilia, and M. Bertolotti, Anal. Sci. 17, 414 (2001); J. C. Krapez and R. Li Voti, Anal. Sci. 17, 417 (2001)], showing their performances and limits of validity for several kinds of photothermal depth profiling problems: The two approaches are based on different mechanisms and exhibit obviously different features. GA may be implemented on the exact heat diffusion equation as follows: one chromosome is associated to each profile. The genetic evolution of the chromosome allows one to find better and better profiles, eventually converging towards the solution of the inverse problem. The main advantage is that GA may be applied to any arbitrary profile, but several disadvantages exist; for example, the complexity of the algorithm, the slow convergence, and consequently the computer time consumed. On the contrary, TWBS uses a simplified theoretical model of heat diffusion in inhomogeneous materials. According to such a model, the photothermal signal depends linearly on the thermal effusivity

Effect of mechanical tissue properties on thermal damage in skin after IR-laser ablation

Energy Technology Data Exchange (ETDEWEB)

Frenz, M.; Romano, V.; Forrer, M.; Weber, H.P. (Inst. of Applied Physics, Bern Univ. (Switzerland)); Mischler, C.; Mueller, O.M. (Anatomical Inst., Bern Univ. (Switzerland))

1991-04-01

The damage created instantaneously in dorsal skin and in the subjacent skeletal muscle layer after CO{sub 2} and Er{sup 3+} laser incisions is histologically and ultrastructurally investigated. Light microscopical examinations show an up to three times larger damage zone in the subcutaneous layer of skeletal muscle than in the connective tissue above. The extent of thermally altered muscle tissue is classified by different zones and characterized by comparison to long time heating injuries. The unexpectedly large damage is a result of the change of elastic properties occurring abruptly at the transition between different materials. This leads to a discontinuity of the cutting dynamics that reduces the ejection of tissue material. We show that the degree of thermal damage originates from the amount of hot material that is not ejected out of the crater acting as a secondary heat source. (orig.).

Study of the skin effect in superconducting materials

Energy Technology Data Exchange (ETDEWEB)

Szeftel, Jacob, E-mail: jszeftel@lpqm.ens-cachan.fr [ENS Cachan, LPQM, 61 avenue du Président Wilson, 94230 Cachan (France); Sandeau, Nicolas [Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille (France); Khater, Antoine [Université du Maine, UMR 6087 Laboratoire PEC, F-72000 Le Mans (France)

2017-05-03

Highlights: • Comprehensive theoretical study of the skin effect in superconductors. • Based on Newton and Maxwell's equations. • Usual and anomalous skin effects dealt with in the same framework. - Abstract: The skin effect is analyzed to provide the numerous measurements of the penetration depth of the electromagnetic field in superconducting materials with a theoretical basis. Both the normal and anomalous skin effects are accounted for within a single framework, focusing on frequencies less than the superconducting gap. The emphasis is laid on the conditions required for the penetration depth to be equal to London's length, which enables us to validate an assumption widely used in the interpretation of all current experimental results.

Lock-in thermal imaging for the early-stage detection of cutaneous melanoma: a feasibility study.

Science.gov (United States)

Bonmarin, Mathias; Le Gal, Frédérique-Anne

2014-04-01

This paper theoretically evaluates lock-in thermal imaging for the early-stage detection of cutaneous melanoma. Lock-in thermal imaging is based on the periodic thermal excitation of the specimen under test. Resulting surface temperature oscillations are recorded with an infrared camera and allow the detection of variations of the sample's thermophysical properties under the surface. In this paper, the steady-state and transient skin surface temperatures are numerically derived for a different stage of development of the melanoma lesion using a two-dimensional axisymmetric multilayer heat-transfer model. The transient skin surface temperature signals are demodulated according to the digital lock-in principle to compute both a phase and an amplitude image of the lesions. The phase image can be advantageously used to accurately detect cutaneous melanoma at an early stage of development while the maximal phase shift can give precious information about the lesion invasion depth. The ability of lock-in thermal imaging to suppress disturbing subcutaneous thermal signals is demonstrated. The method is compared with the previously proposed pulse-based approaches, and the influence of the modulation frequency is further discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of Thermal Equilibrium in a Sealed Cell Based on Optical Depth

Energy Technology Data Exchange (ETDEWEB)

Zou, Sheng; Zhang, Hong; Chen, Xi-yuan [Southeast University, Nanjing (China); Shan, Guang-cun; Quan, Wei [Beihang University, Beijing (China)

2017-01-15

An effective method based on optical depth (OD) is presented to measure thermal equilibrium in a cell. First, the principle of determining the temperature distribution in the cell by using the OD is demonstrated. Subsequently, relevant experiments are carried out. Original experimental results showed that some gradients of OD distributions in the cell at different wavelengths and variations of the OD increased slowly along the direction of motion of the beam at a fixed wavelength. At a wavelength of 766.6839 nm, which is about 7 GHz blue shifted with respect to the potassium resonance, the average value of the OD was about 0.764 and the maximal and the minimum inhomogeneity biases among all location points were about 6.07% and 0.56%, respectively. As for the corresponding wavelengths of 766.67785 nm and 766.73004 nm, some deviations from previous results, which were caused by different absorptions of the alkali-metal atoms at different frequencies of the laser beam, were observed. The nonuniform OD values along the direction of motion of the beam reflected an inhomogeneous distribution of the temperature in the cell, which may have been caused by layout of the oven. When the layout of the oven was modified, comparative experiments comparable to these with the previous layout of the oven demonstrated that the uniformity of the temperature distribution in the cell was improved and that thermal equilibrium time was shorter by about 10 minutes. This method played an important role in determining the thermal equilibrium time in the cell.

Three-dimensional morphological characterization of the skin surface micro-topography using a skin replica and changes with age.

Science.gov (United States)

Masuda, Y; Oguri, M; Morinaga, T; Hirao, T

2014-08-01

Skin surface micro-topography (SSMT), consisting of pores, ridges and furrows, reflects the skin condition and is an important factor determining the aesthetics of the skin. Most previous studies evaluating SSMT have employed two-dimensional image analysis of magnified pictures captured by a video microscope. To improve the accuracy of SSMT analysis, we established a three-dimensional (3D) analysis method for SSMT and developed various parameters including the skin ridge number, and applied the method to study the age-dependent change in skin. Confocal laser scanning microscopy was used for 3D measurement of the surface morphology of silicon replicas taken from the cheek. We then used these data to calculate the parameters that reflect the nature of SSTM including the skin ridge number using originally developed software. Employing a superscription technique, we investigated the variation in SSMT with age for replicas taken from the cheeks of 103 Japanese females (5-85 years old). The skin surface area and roughness, the area of pores, the area, length, depth and width of skin furrows and the number of skin ridges were examined. The surface roughness, the area of pores and the depth of skin furrows increased with age. The area and length of skin furrows and the number of skin ridges decreased with age. The method proposed to analyse SSMT three dimensionally is an effective tool with which to characterize the condition of the skin. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Skin histology and its role in heat dissipation in three pinniped species

Directory of Open Access Journals (Sweden)

Khamas Wael A

2012-08-01

Full Text Available Abstract Background Pinnipeds have a thick blubber layer and may have difficulty maintaining their body temperature during hot weather when on land. The skin is the main thermoregulatory conduit which emits excessive body heat. Methods Thorough evaluation of the skin histology in three pinniped species; the California sea lion-Zalophus californianus, the Pacific harbor seal-Phoca vitulina richardsi, and the Northern elephant seal-Mirounga angustirostris, was conducted to identify the presence, location and distribution of skin structures which contribute to thermoregulation. These structures included hair, adipose tissue, sweat glands, vasculature, and arteriovenous anastomoses (AVA. Thermal imaging was performed on live animals of the same species to correlate histological findings with thermal emission of the skin. Results The presence and distribution of skin structures directly relates to emissivity of the skin in all three species. Emissivity of skin in phocids (Pacific harbor and Northern elephant seals follows a different pattern than skin in otariids (California sea lions. The flipper skin in phocids tends to be the most emissive region during hot weather and least emissive during cold weather. On the contrary in otariids, skin of the entire body has a tendency to be emissive during both hot and cold weather. Conclusion Heat dissipation of the skin directly relates to the presence and distribution of skin structures in all three species. Different skin thermal dissipation patterns were observed in phocid versus otariid seals. Observed thermal patterns can be used for proper understanding of optimum thermal needs of seals housed in research facilities, rescue centers and zoo exhibits.

Assessing burn depth in tattooed burn lesions with LASCA Imaging

Science.gov (United States)

Krezdorn, N.; Limbourg, A.; Paprottka, F.J.; Könneker; Ipaktchi, R.; Vogt, P.M

2016-01-01

Summary Tattoos are on the rise, and so are patients with tattooed burn lesions. A proper assessment with regard to burn depth is often impeded by the tattoo dye. Laser speckle contrast analysis (LASCA) is a technique that evaluates burn lesions via relative perfusion analysis. We assessed the effect of tattoo skin pigmentation on LASCA perfusion imaging in a multicolour tattooed patient. Depth of burn lesions in multi-coloured tattooed and untattooed skin was assessed using LASCA. Relative perfusion was measured in perfusion units (PU) and compared to various pigment colours, then correlated with the clinical evaluation of the lesion. Superficial partial thickness burn (SPTB) lesions showed significantly elevated perfusion units (PU) compared to normal skin; deep partial thickness burns showed decreased PU levels. PU of various tattoo pigments to normal skin showed either significantly lower values (blue, red, pink) or significantly increased values (black) whereas orange and yellow pigment showed values comparable to normal skin. In SPTB, black and blue pigment showed reduced perfusion; yellow pigment was similar to normal SPTB burn. Deep partial thickness burn (DPTB) lesions in tattoos did not show significant differences to normal DPTB lesions for black, green and red. Tattoo pigments alter the results of perfusion patterns assessed with LASCA both in normal and burned skin. Yellow pigments do not seem to interfere with LASCA assessment. However proper determination of burn depth both in SPTB and DPTB by LASCA is limited by the heterogenic alterations of the various pigment colours. PMID:28149254

Thermal neutron dose calculation in synovium membrane for BNCS

International Nuclear Information System (INIS)

Abdalla, Khalid; Naqvi, A.A.; Maalej, N.; El-Shahat, B.

2006-01-01

A D(d,n) reaction based setup has been optimized for Boron Neutron Capture Synovectomy (BNCS). The polyethylene moderator and graphite reflector sizes were optimized to deliver the highest ratio of thermal to fast neutron yield. The neutron dose was calculated at various depths in a knee phantom loaded with boron to determine therapeutic ratios of synovium dose/skin dose and synovium dose/bone dose. Normalized to same boron loading in synovium, the values of the therapeutic ratios obtained in the present study are 12-30 times higher than the published values. (author)

ANALYSIS OF NON-FOURIER THERMAL BEHAVIOUR FOR MULTI-LAYER SKIN MODEL

Directory of Open Access Journals (Sweden)

Kuo-Chi Liu

2011-01-01

Full Text Available This paper studies the effect of micro-structural interaction on bioheat transfer in skin, which was stratified into epidermis, dermis, and subcutaneous. A modified non-Fourier equation of bio-heat transfer was developed based on the second-order Taylor expansion of dual-phase-lag model and can be simplified as the bio-heat transfer equations derived from Pennes' model, thermal wave model, and the linearized form of dual-phase-lag model. It is a fourth order partial differential equation, and the boundary conditions at the interface between two adjacent layers become complicated. There are mathematical difficulties in dealing with such a problem. A hybrid numerical scheme is extended to solve the present problem. The numerical results are in a good agreement with the contents of open literature. It evidences the rationality and reliability of the present results.

Histological case-control study of peeling-induced skin changes by different peeling agents in surgically subcutaneous undermined skin flaps in facelift patients.

Science.gov (United States)

Gonser, P; Kaestner, S; Jaminet, P; Kaye, K

2017-11-01

A histological evaluation of peeling-induced skin changes in subcutaneous undermined preauricular facial skin flaps of nine patients was performed. There were three treatment groups: Trichloroacetic acid (TCA) 25%, TCA 40% and phenol/croton oil; one group served as control. Two independent evaluators determined the epidermal and dermal thickness and the depth of necrosis (micrometre). The percentual tissue damage due to the peeling was calculated, and a one-sample t-test for statistical significance was performed. On the basis of the histomorphological changes, peeling depth was classified as superficial, superficial-partial, deep-partial and full thickness chemical burn. The histological results revealed a progression of wound depth for different peeling agents without full thickness necrosis. TCA peels of up to 40% can be safely applied on subcutaneous undermined facial skin flaps without impairing the vascular patency, producing a predictable chemical burn, whereas deep peels such as phenol/croton oil peels should not be applied on subcutaneous undermined skin so as to not produce skin slough or necrosis by impairing vascular patency. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Electronic equilibrium as a function of depth in tissue from cobalt-60 point source exposures

International Nuclear Information System (INIS)

Myrick, J.A.

1994-08-01

The Nuclear Regulatory Commission has set the basic criteria for assessing skin dose stemming from hot particle contaminations. Compliance with 10 CFR 20.101 requires that exposure to the skin be evaluated over a 1 cm 2 area at a depth of 0.007 cm. Skin exposure can arise from both the beta and gamma components of radioactive particles and gamma radiation can contribute significantly to skin doses. The gamma component of dose increases dramatically when layers of protective clothing are interposed between the hot particle source and the skin, and in cases where the hot particle is large in comparison to the range of beta particles. Once the protective clothing layer is thicker than the maximum range of the beta particles, skin dose is due solely to gamma radiation. Charged particle equilibrium is not established at shallow depths. The degree of electronic equilibrium establishment must be assessed for shallow doses to prevent the over-assessment of skin dose because conventional fluence-to-dose conversion factors are not applicable. To assess the effect of electronic equilibrium, selected thicknesses of tissue equivalent material were interposed between radiochromic dye film and a 60 Co hot particle source and dose was measured as a function of depth. These measured values were then compared to models which are used to calculate charged particle equilibrium. The Miller-Reece model was found to agree closely with the experimental data while the Lantz-Lambert model overestimated dose at shallow depths

Comparative performance analysis of the artificial-intelligence-based thermal control algorithms for the double-skin building

International Nuclear Information System (INIS)

Moon, Jin Woo

2015-01-01

This study aimed at developing artificial-intelligence-(AI)-theory-based optimal control algorithms for improving the indoor temperature conditions and heating energy efficiency of the double-skin buildings. For this, one conventional rule-based and four AI-based algorithms were developed, including artificial neural network (ANN), fuzzy logic (FL), and adaptive neuro fuzzy inference systems (ANFIS), for operating the surface openings of the double skin and the heating system. A numerical computer simulation method incorporating the matrix laboratory (MATLAB) and the transient systems simulation (TRNSYS) software was used for the comparative performance tests. The analysis results revealed that advanced thermal-environment comfort and stability can be provided by the AI-based algorithms. In particular, the FL and ANFIS algorithms were superior to the ANN algorithm in terms of providing better thermal conditions. The ANN-based algorithm, however, proved its potential to be the most energy-efficient and stable strategy among the four AI-based algorithms. It can be concluded that the optimal algorithm can be differently determined according to the major focus of the strategy. If comfortable thermal condition is the principal interest, then the FL or ANFIS algorithm could be the proper solution, and if energy saving for space heating and system operation stability is the main concerns, then the ANN-based algorithm may be applicable. - Highlights: • Integrated control algorithms were developed for the heating system and surface openings. • AI theories were applied to the control algorithms. • ANN, FL, and ANFIS were the applied AI theories. • Comparative performance tests were conducted using computer simulation. • AI algorithms presented superior temperature environment.

The interrealtionship between locally applied heat, ageing and skin blood flow on heat transfer into and from the skin.

Science.gov (United States)

Petrofsky, Jerrold; Alshahmmari, Faris; Yim, Jong Eun; Hamdan, Adel; Lee, Haneul; Neupane, Sushma; Shetye, Gauri; Moniz, Harold; Chen, Wei-Ti; Cho, Sungkwan; Pathak, Kunal; Malthane, Swapnil; Shenoy, Samruddha; Somanaboina, Karunakar; Alshaharani, Mastour; Nevgi, Bhakti; Dave, Bhargav; Desai, Rajavi

2011-07-01

In response to a thermal stress, skin blood flow (BF) increases to protect the skin from damage. When a very warm, noxious, heat source (44 °C) is applied to the skin, the BF increases disproportionately faster than the heat stress that was applied, creating a safety mechanism for protecting the skin. In the present investigation, the rate of rise of BF in response to applied heat at temperatures between 32 °C and 40 °C was examined as well as the thermal transfer to and from the skin with and without BF in younger and older subjects to see how the skin responds to a non-noxious heat source. Twenty male and female subjects (10 - 20-35 years, 10 - 40-70 years) were examined. The arms of the subjects were passively heated for 6 min with and without vascular occlusion by a thermode at temperatures of 32, 36, 38 or 40 °C. When occlusion was not used during the 6 min exposure to heat, there was an exponential rise in skin temperature and BF in both groups of subjects over the 6-min period. However, the older subjects achieved similar skin temperatures but with the expenditure of fewer calories from the thermode than was seen for the younger subjects (p<0.05). BF was significantly less in the older group than the younger group at rest and after exposure to each of the three warmest thermode temperatures (p<0.05). As was seen for noxious temperatures, after a delay, the rate of rise of BF at the three warmest thermode temperatures was faster than the rise in skin temperature in the younger group but less in the older group of subjects. Thus, a consequence of ageing is reduced excess BF in response to thermal stress increasing susceptibility to thermal damage. This must be considered in modelling of BF. Copyright © 2011 Informa UK, Ltd.

Rock-Eval analysis of French forest soils: the influence of depth, soil and vegetation types on SOC thermal stability and bulk chemistry

Science.gov (United States)

Soucemarianadin, Laure; Cécillon, Lauric; Baudin, François; Cecchini, Sébastien; Chenu, Claire; Mériguet, Jacques; Nicolas, Manuel; Savignac, Florence; Barré, Pierre

2017-04-01

Soil organic matter (SOM) is the largest terrestrial carbon pool and SOM degradation has multiple consequences on key ecosystem properties like nutrients cycling, soil emissions of greenhouse gases or carbon sequestration potential. With the strong feedbacks between SOM and climate change, it becomes particularly urgent to develop reliable routine methodologies capable of indicating the turnover time of soil organic carbon (SOC) stocks. Thermal analyses have been used to characterize SOM and among them, Rock-Eval 6 (RE6) analysis of soil has shown promising results in the determination of in-situ SOC biogeochemical stability. This technique combines a phase of pyrolysis followed by a phase of oxidation to provide information on both the SOC bulk chemistry and thermal stability. We analyzed with RE6 a set of 495 soils samples from 102 permanent forest sites of the French national network for the long-term monitoring of forest ecosystems (''RENECOFOR'' network). Along with covering pedoclimatic variability at a national level, these samples include a range of 5 depths up to 1 meter (0-10 cm, 10-20 cm, 20-40 cm, 40-80 cm and 80-100 cm). Using RE6 parameters that were previously shown to be correlated to short-term (hydrogen index, HI; T50 CH pyrolysis) or long-term (T50 CO2 oxidation and HI) SOC persistence, and that characterize SOM bulk chemical composition (oxygen index, OI and HI), we tested the influence of depth (n = 5), soil class (n = 6) and vegetation type (n = 3; deciduous, coniferous-fir, coniferous-pine) on SOM thermal stability and bulk chemistry. Results showed that depth was the dominant discriminating factor, affecting significantly all RE6 parameters. With depth, we observed a decrease of the thermally labile SOC pool and an increase of the thermally stable SOC pool, along with an oxidation and a depletion of hydrogen-rich moieties of the SOC. Soil class and vegetation type had contrasted effects on the RE6 parameters but both affected significantly T

Thermal inactivation of Salmonella Enteritidis on chicken skin previously exposed to acidified Sodium chlorite or tri-sodium phosphate.

Science.gov (United States)

Karuppasamy, K; Yadav, Ajit S; Saxena, Gaurav K

2015-12-01

Thermal inactivation of normal and starved cells of Salmonella Enteritidis on chicken skin previously exposed to different concentrations of acidified sodium chlorite (ASC) or tri-sodium phosphate (TSP) was investigated. Inoculated skin was pretreated with different concentration of ASC or TSP, packaged in bags, and then immersed in a circulating water bath at 60 to 68 °C. The recovery medium was Hektoen enteric agar. D-values, determined by linear regression, for normal cells on chicken skin, were 2.79, 1.17 and 0.53 min whereas D-values for starved cells were 4.15, 1.83 and 0.66 at 60, 64 and 68 °C, respectively. z-values for normal cells were 3.54 and for starved cells were 2.29. Pretreatment of Salmonella Enteritidis cells with 0 to 200 ppm of ASC or 0 to 1.0 % TSP resulted in lower D-values at all temperatures. Sensory results indicated no significance differences for control and treatments. Thus, results of this study indicated that pretreatment of chicken skin with ASC or TSP increased sensitivity of Salmonella Enteritidis to heat without affecting organoleptic quality of chicken meat.

Contribution of human skin topography to the characterization of dynamic skin tension during senescence: morpho-mechanical approach

International Nuclear Information System (INIS)

Zahouani, H; Djaghloul, M; Vargiolu, R; Mezghani, S; Mansori, M E L

2014-01-01

The structuring of the dermis with a network of collagen and elastic fibres gives a three-dimensional structure to the skin network with directions perpendicular and parallel to the skin surface. This three-dimensional morphology prints on the surface of the stratum corneum a three dimensional network of lines which express the mechanical tension of the skin at rest. To evaluate the changes of skin morphology, we used a three-dimensional confocal microscopy and characterization of skin imaging of volar forearm microrelief. We have accurately characterize the role of skin line network during chronological aging with the identification of depth scales on the network of lines (z ≤ 60μm) and the network of lines covering Langer's lines (z > 60 microns). During aging has been highlighted lower rows for elastic fibres, the decrease weakened the tension and results in enlargement of the plates of the microrelief, which gives us a geometric pertinent indicator to quantify the loss of skin tension and assess the stage of aging. The study of 120 Caucasian women shows that ageing in the volar forearm zone results in changes in the morphology of the line network organisation. The decrease in secondary lines (z ≤ 60 μm) is counterbalanced by an increase in the depth of the primary lines (z > 60 μm) and an accentuation of the anisotropy index

Composition of minerals and trace elements at Mamasani thermal source: A possible preventive treatment for some skin diseases

Science.gov (United States)

Hamidizadeh, Nasrin; Simaeetabar, Shima; Handjani, Farhad; Ranjbar, Sara; Moghadam, Mohammad Gohari; Parvizi, Mohammad Mahdi

2017-01-01

INTRODUCTION: Some skin diseases are incurable and modern medicine can only control them. In addition, alternative treatment remedies including balneotherapy can be effective in improving skin conditions. However, there are only a limited number of studies on particular mineral or trace elements of mineral sources that have been identified in Iran. In this respect, the amount of minerals and trace elements in Mamasani thermal source, Fars Province, Iran, was measured using electrochemical, titration, and spectrophotometric methods and evaluated. MATERIALS AND METHODS: The amount of minerals and trace elements in Mamasani thermal source, Fars Province, Iran, was measured using electrochemical, titration, and spectrophotometric methods. RESULTS: The concentrations of natural gases such as H2S and NO3 in Mamasani thermal source were measured to be 22.10 mg/L and 42.79 mg/L, respectively. The source also contained major ions such as chloride, sulfate, sodium, calcium, magnesium, potassium, and carbonate. Due to the high concentration of chloride, sulfate, and sodium ions in comparison with other major ions, the water source is also classified as sulfide water. The existing trace elements in this thermal water source are iron, zinc, copper, selenium, cobalt, chromium, boron, silisium, aluminum, magnesium, and molybdenum. CONCLUSION: We concluded that bathing in this source could be beneficial. As nitrate concentration is close to the highest standard concentration for drinking water, it can be used in chronic dermatitis, psoriasis, burns, and allergy. Furthermore, the antibacterial and antifungal effects of sulfur-containing water in this source can be helpful in the treatment of leg ulcers, tinea versicolor, tinea corporis, and tinea capitis. PMID:29296611

Skin Bioprinting: Impending Reality or Fantasy?

Science.gov (United States)

Ng, Wei Long; Wang, Shuai; Yeong, Wai Yee; Naing, May Win

2016-09-01

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Skin and psyche--from the surface to the depth of the inner world.

Science.gov (United States)

Beltraminelli, Helmut; Itin, Peter

2008-01-01

About 30% of dermatology patients have signs or symptoms of psychological problems. Dermatologists should be familiar with the basics needed to identify, advise and treat these patients. Because of the complex interaction between skin and psyche, it is difficult to distinguish whether the primary problem is the skin or the psyche. Sometimes the clinical picture is a consequence of interactions between them and other factors. The interactions between skin and psyche are well known in history, art and literature--perhaps better known today because the marked emphasis on such images in our modern multimedia society. Aging is increasingly perceived as an illness and not as a physiological process. Through globalization, many different cultural approaches to the skin have entered in our daily life and influence our communication. This article considers the most important dermatoses which often show primary or secondary interaction with the psyche.

Evaluating local and overall thermal comfort in buildings using thermal manikins

Energy Technology Data Exchange (ETDEWEB)

Foda, E.

2012-07-01

Evaluation methods of human thermal comfort that are based on whole-body heat balance with its surroundings may not be adequate for evaluations in non-uniform thermal conditions. Under these conditions, the human body's segments may experience a wide range of room physical parameters and the evaluation of the local (segmental) thermal comfort becomes necessary. In this work, subjective measurements of skin temperature were carried out to investigate the human body's local responses due to a step change in the room temperature; and the variability in the body's local temperatures under different indoor conditions and exposures as well as the physiological steady state local temperatures. Then, a multi-segmental model of human thermoregulation was developed based on these findings to predict the local skin temperatures of individuals' body segments with a good accuracy. The model predictability of skin temperature was verified for steady state and dynamic conditions using measured data at uniform neutral, cold and warm as well as different asymmetric thermal conditions. The model showed very good predictability with average absolute deviation ranged from 0.3-0.8 K. The model was then implemented onto the control system of the thermal manikin 'THERMINATOR' to adjust the segmental skin temperature set-points based on the indoor conditions. This new control for the manikin was experimentally validated for the prediction of local and overall thermal comfort using the equivalent temperature measure. THERMINATOR with the new control mode was then employed in the evaluation of localized floor-heating system variants towards maximum energy efficiency. This aimed at illustrating a design strategy using the thermal manikin to find the optimum geometry and surface area of a floor-heater for a single seated person. Furthermore, a psychological comfort model that is based on local skin temperature was adapted for the use with the model of human

Temperature modulation of the visible and near infrared absorption and scattering coefficients of human skin.

Science.gov (United States)

Khalil, Omar S; Yeh, Shu-Jen; Lowery, Michael G; Wu, Xiaomao; Hanna, Charles F; Kantor, Stanislaw; Jeng, Tzyy-Wen; Kanger, Johannes S; Bolt, Rene A; de Mul, Frits F

2003-04-01

We determine temperature effect on the absorption and reduced scattering coefficients (mu(a) and mu(s)(')) of human forearm skin. Optical and thermal simulation data suggest that mu( a) and mu(s)(') are determined within a temperature-controlled depth of approximately 2 mm. Cutaneous mu(s)(') change linearly with temperature. Change in mu(a) was complex and irreversible above body normal temperatures. Light penetration depth (delta) in skin increased on cooling, with considerable person-to-person variations. We attribute the effect of temperature on mu(s)(') to change in refractive index mismatch, and its effect on mu(a) to perfusion changes. The reversible temperature effect on mu (s)(' ) was maintained during more than 90 min. contact between skin and the measuring probe, where temperature was modulated between 38 and 22 degrees C for multiple cycles While temperature modulated mu(s)(' ) instantaneously and reversibly, mu(a) exhibited slower response time and consistent drift. There was a statistically significant upward drift in mu(a) and a mostly downward drift in mu( s)(') over the contact period. The drift in temperature-induced fractional change in mu(s)(') was less statistically significant than the drift in mu(s)('). Deltamu( s)(') values determined under temperature modulation conditions may have less nonspecific drift than mu(s)(') which may have significance for noninvasive determination of analytes in human tissue.

Adaptive Neuro-Fuzzy Inference System (ANFIS)-Based Models for Predicting the Weld Bead Width and Depth of Penetration from the Infrared Thermal Image of the Weld Pool

Science.gov (United States)

Subashini, L.; Vasudevan, M.

2012-02-01

Type 316 LN stainless steel is the major structural material used in the construction of nuclear reactors. Activated flux tungsten inert gas (A-TIG) welding has been developed to increase the depth of penetration because the depth of penetration achievable in single-pass TIG welding is limited. Real-time monitoring and control of weld processes is gaining importance because of the requirement of remoter welding process technologies. Hence, it is essential to develop computational methodologies based on an adaptive neuro fuzzy inference system (ANFIS) or artificial neural network (ANN) for predicting and controlling the depth of penetration and weld bead width during A-TIG welding of type 316 LN stainless steel. In the current work, A-TIG welding experiments have been carried out on 6-mm-thick plates of 316 LN stainless steel by varying the welding current. During welding, infrared (IR) thermal images of the weld pool have been acquired in real time, and the features have been extracted from the IR thermal images of the weld pool. The welding current values, along with the extracted features such as length, width of the hot spot, thermal area determined from the Gaussian fit, and thermal bead width computed from the first derivative curve were used as inputs, whereas the measured depth of penetration and weld bead width were used as output of the respective models. Accurate ANFIS models have been developed for predicting the depth of penetration and the weld bead width during TIG welding of 6-mm-thick 316 LN stainless steel plates. A good correlation between the measured and predicted values of weld bead width and depth of penetration were observed in the developed models. The performance of the ANFIS models are compared with that of the ANN models.

Effect of compression stockings on cutaneous microcirculation: Evaluation based on measurements of the skin thermal conductivity.

Science.gov (United States)

Grenier, E; Gehin, C; McAdams, E; Lun, B; Gobin, J-P; Uhl, J-F

2016-03-01

To study of the microcirculatory effects of elastic compression stockings. In phlebology, laser Doppler techniques (flux or imaging) are widely used to investigate cutaneous microcirculation. It is a method used to explore microcirculation by detecting blood flow in skin capillaries. Flux and imaging instruments evaluate, non-invasively in real-time, the perfusion of cutaneous micro vessels. Such tools, well known by the vascular community, are not really suitable to our protocol which requires evaluation through the elastic compression stockings fabric. Therefore, we involve another instrument, called the Hematron (developed by Insa-Lyon, Biomedical Sensor Group, Nanotechnologies Institute of Lyon), to investigate the relationship between skin microcirculatory activities and external compression provided by elastic compression stockings. The Hematron measurement principle is based on the monitoring of the skin's thermal conductivity. This clinical study examined a group of 30 female subjects, aged 42 years ±2 years, who suffer from minor symptoms of chronic venous disease, classified as C0s, and C1s (CEAP). The resulting figures show, subsequent to the pressure exerted by elastic compression stockings, an improvement of microcirculatory activities observed in 83% of the subjects, and a decreased effect was detected in the remaining 17%. Among the total population, the global average increase of the skin's microcirculatory activities is evaluated at 7.63% ± 1.80% (p compression stockings has a direct influence on the skin's microcirculation within this female sample group having minor chronic venous insufficiency signs. Further investigations are required for a deeper understanding of the elastic compression stockings effects on the microcirculatory activity in venous diseases at other stages of pathology. © The Author(s) 2014.

Skin Sensitive Difference of Human Body Sections under Clothing-Smirnov Test of Skin Surface Temperatures' Dynamic Changing

Institute of Scientific and Technical Information of China (English)

LI Jun; WU Hai-yan; WANG Yun-yi

2004-01-01

Skin sensitive difference of human body sections under clothing is the theoretic foundation of thermal insulation clothing design.By a new method of researching on clothing comfort perception,the skin temperature live changing procedure of human body sections affected by the same cold stimulation is inspected.Furthermore with the Smirnov test the skin temperatures dynamic changing patterns of main human body sections are obtained.

Multilayer detector for measuring absorbed dose in skin

International Nuclear Information System (INIS)

Osanov, D.P.; Panova, V.P.; Shaks, A.I.

1985-01-01

A method of skin dosimetry using multilayer dosimeters is described that allows the skin-depth distribution of absorbed dose to be estimated. A method of quantitative estimation and prediction of the degree of skin radiation damage using a three-layer dosimeter is demonstrated. Dosimeters are holders of tissue-equivalent material that contain photographic film, a scintillator, thermoluminophor, or any other radiation-sensitive element

SU-E-J-273: Skin Temperature Recovery Rate as a Potential Predictor for Radiation-Induced Skin Reactions

Energy Technology Data Exchange (ETDEWEB)

Biswal, N C; Wu, Z; Chu, J [Rush University Medical Center, Chicago, IL (United States); Sun, J [Argonne National Laboratory, Lemont, IL (United States)

2015-06-15

Purpose: To assess the potential of dynamic infrared imaging to evaluate early skin reactions during radiation therapy in cancer patients. Methods: Thermal images were captured by our home-built system consisting of two flash lamps and an infrared (IR) camera. The surface temperature of the skin was first raised by ∼ 6 °C from ∼1 ms short flashes; the camera then captured a series of IR images for 10 seconds. For each image series, a basal temperature was recorded for 0.5 seconds before flash was triggered. The temperature gradients (ε) were calculated between a reference point (immediately after the flash) and at a time point of 2sec, 4sec and 9sec after that. A 1.0 cm region of interest (ROI) on the skin was drawn; the mean and standard deviations of the ROIs were calculated. The standard ε values for normal human skins were evaluated by imaging 3 healthy subjects with different skin colors. All of them were imaged on 3 separate days for consistency checks. Results: The temperature gradient, which is the temperature recovery rate, depends on the thermal properties of underlying tissue, i.e. thermal conductivity. The average ε for three volunteers averaged over 3 measurements were 0.64±0.1, 0.72±0.2 and 0.80±0.3 at 2sec, 4sec and 9sec respectively. The standard deviations were within 1.5%–3.2%. One of the volunteers had a prior small skin burn on the left wrist and the ε values for the burned site were around 9% (at 4sec) and 13% (at 9sec) lower than that from the nearby normal skin. Conclusion: The temperature gradients from the healthy subjects were reproducible within 1.5%–3.2 % and that from a burned skin showed a significant difference (9%–13%) from the normal skin. We have an IRB approved protocol to image head and neck patients scheduled for radiation therapy.

SU-E-J-273: Skin Temperature Recovery Rate as a Potential Predictor for Radiation-Induced Skin Reactions

International Nuclear Information System (INIS)

Biswal, N C; Wu, Z; Chu, J; Sun, J

2015-01-01

Purpose: To assess the potential of dynamic infrared imaging to evaluate early skin reactions during radiation therapy in cancer patients. Methods: Thermal images were captured by our home-built system consisting of two flash lamps and an infrared (IR) camera. The surface temperature of the skin was first raised by ∼ 6 °C from ∼1 ms short flashes; the camera then captured a series of IR images for 10 seconds. For each image series, a basal temperature was recorded for 0.5 seconds before flash was triggered. The temperature gradients (ε) were calculated between a reference point (immediately after the flash) and at a time point of 2sec, 4sec and 9sec after that. A 1.0 cm region of interest (ROI) on the skin was drawn; the mean and standard deviations of the ROIs were calculated. The standard ε values for normal human skins were evaluated by imaging 3 healthy subjects with different skin colors. All of them were imaged on 3 separate days for consistency checks. Results: The temperature gradient, which is the temperature recovery rate, depends on the thermal properties of underlying tissue, i.e. thermal conductivity. The average ε for three volunteers averaged over 3 measurements were 0.64±0.1, 0.72±0.2 and 0.80±0.3 at 2sec, 4sec and 9sec respectively. The standard deviations were within 1.5%–3.2%. One of the volunteers had a prior small skin burn on the left wrist and the ε values for the burned site were around 9% (at 4sec) and 13% (at 9sec) lower than that from the nearby normal skin. Conclusion: The temperature gradients from the healthy subjects were reproducible within 1.5%–3.2 % and that from a burned skin showed a significant difference (9%–13%) from the normal skin. We have an IRB approved protocol to image head and neck patients scheduled for radiation therapy

Evaluation of carburization depth in service exposed ferritic steel using magnetic Barkhausen noise analysis

International Nuclear Information System (INIS)

Vaidyanathan, S.; Moorthy, V.; Jayakumar, T.; Baldev Raj

1996-01-01

The feasibility of using magnetic Barkhausen (MBN) measurement for the evaluation of carburization depth in ferritic steels has been reported in this paper. MBN measurements were carried out on samples from service exposed 0.5Cr-0.5Mo ferritic steel tube at different depths (cross section) from carburised ID surface to simulate the variation in carbon concentration gradient within the skin depth of MBN with increasing time of exposure to carburization. It has been observed that the MBN level increases with increasing depth of measurement. An inverse relation between MBN level and carbon content/hardness value has been observed. This study suggests that, the MBN measurements on the carburised surface can be correlated with the concentration gradient within the skin depth of the MBN which would help in predicting the approximate depth of the carburised layer with proper prior calibration. (author)

Evaluation of skin firmness by the DynaSKIN, a novel non-contact compression device, and its use in revealing the efficacy of a skincare regimen featuring a novel anti-ageing ingredient, acetyl aspartic acid.

Science.gov (United States)

Kearney, E M; Messaraa, C; Grennan, G; Koeller, G; Mavon, A; Merinville, E

2017-05-01

One of the key strategies for anti-ageing in the cosmetics industry today is to target the structural changes responsible for ptosis of the skin, given its impact on age perception. Several objective and non-invasive methods are available to characterise the biomechanical properties of the skin, which are operator-dependent, involving skin contact and providing single-dimensional numerical descriptions of skin behaviour. The research introduces the DynaSKIN, a device using non-contact mechanical pressure in combination with fringe projection to quantify and visualise the skin response in 3-dimensions. We examine the age correlation of the measurements, how they compare with the Cutometer ® , and measure skin dynamics following application of a skincare regimen containing established anti-ageing ingredients. DynaSKIN and Cutometer ® measurements were made on the cheek of 80 Caucasian women (18-64 years). DynaSKIN volume, mean depth and maximum depth parameters were correlated with age and 15 Cutometer ® parameters. Subsequently, the firming efficacy of a skincare regimen featuring acetyl aspartic acid (AAA) and a peptide complex was examined in a cohort of 41 volunteers. DynaSKIN volume, mean depth and maximum depth parameters correlate with age and the Cutometer ® parameters that are associated with the skin relaxation phase (R1, R2, R4, R5, R7 and F3). Furthermore, the DynaSKIN captured significant improvements in skin firmness delivered by the skincare regimen. The DynaSKIN is a novel device capable of capturing skin biomechanics at a high level of specificity and successfully detected the firming properties of a skincare regimen. Its independent measuring principle, consumer relevance and skin firmness 3D visualisation capabilities bring objectivity and novelty to product efficacy substantiation evaluation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Thermal mapping on male genital and skin tissues of laptop thermal sources and electromagnetic interaction.

Science.gov (United States)

Safari, Mahdi; Mosleminiya, Navid; Abdolali, Ali

2017-10-01

Since the development of communication devices and expansion of their applications, there have been concerns about their harmful health effects. The main aim of this study was to investigate laptop thermal effects caused by exposure to electromagnetic fields and thermal sources simultaneously; propose a nondestructive, replicable process that is less expensive than clinical measurements; and to study the effects of positioning any new device near the human body in steady state conditions to ensure safety by U.S. and European standard thresholds. A computer simulation was designed to obtain laptop heat flux from SolidWorks flow simulation. Increase in body temperature due to heat flux was calculated, and antenna radiation was calculated using Computer Simulation Technology (CST) Microwave Studio software. Steady state temperature and specific absorption rate (SAR) distribution in user's body, and heat flux beneath the laptop, were obtained from simulations. The laptop in its high performance mode caused 420 (W/m 2 ) peak two-dimensional heat flux beneath it. The cumulative effect of laptop in high performance mode and 1 W antenna radiation resulted in temperatures of 42.9, 38.1, and 37.2 °C in lap skin, scrotum, and testis, that is, 5.6, 2.1, and 1.4 °C increase in temperature, respectively. Also, 1 W antenna radiation caused 0.37 × 10 -3 and 0.13 × 10 -1 (W/kg) peak three-dimensional SAR at 2.4 and 5 GHz, respectively, which could be ignored in reference to standards and temperature rise due to laptop use. Bioelectromagnetics. 38:550-558, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

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

Science.gov (United States)

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

2017-12-27

Quantitative assessment of possible linkages between skin's firmness and water content is useful for cosmetic and clinical purposes and to better understand features of advancing age. Our goals were to characterize age-related differential features in skin firmness in women and determine the relationship between skin firmness and indices of skin water. Skin firmness was quantified using handheld devices that measure the force to indent skin 0.3 and 1.3 mm (F0.3 and F1.3). Skin hydration was quantified using handheld devices that measured tissue dielectric constant (TDC) at 300 MHz to skin depths of 0.5 and 2.0-2.5 mm. All parameters were measured bilaterally in the jowl area and volar forearm of 60 women grouped by age skin depths, as weakly related to firmness and was observed to change with age only when measured to a depth of 0.5 mm represented by TDC5 = 0.096 × AGE + 32.7. Experimental finding show clear differences in skin firmness between age-groups with skin hydration playing a minor role. Possible explanations and suggestions for further studies are provided. © 2017 Wiley Periodicals, Inc.

Light absorption in blood during low-intensity laser irradiation of skin

International Nuclear Information System (INIS)

Barun, V V; Ivanov, A P

2010-01-01

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. (laser methods in medicine)

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.

Influence of crosslinking agents on the pore structure of skin.

Science.gov (United States)

Fathima, N Nishad; Dhathathreyan, Aruna; Ramasami, T

2007-05-15

Analysis of pore structure of skin is important to understand process of diffusion and adsorption involved during any application of the skin matrix. In this study, the effect of thermal shrinkage on the pore structure of chromium and vegetable treated skin has been analyzed as these tanning agents are known to bring about thermal stability to the matrix. The changes brought about in the pore structure have been studied using mercury intrusion porosimetry and scanning electron microscopy. Response of the chromium treated and vegetable tanning treated skin structure to heat has been found to be quite different from each other. About 41% decrease in porosity is observed for chromium treated skin as against 97% decrease for the skin treated with vegetable tannins. This is primarily attributed to the basic nature of these materials and the nature of interaction of them towards skin.

Effect of skin tumor properties on laser penetration

CSIR Research Space (South Africa)

Karsten, AE

2009-06-01

Full Text Available Computer modeling can be a valuable tool to determine the absorption of laser light in different skin layers. For this study, the optical properties of three different skin tumors were used in the model to evaluate the effect on penetration depth...

"Why not bathe the baby today?": A qualitative study of thermal care beliefs and practices in four African sites.

Science.gov (United States)

Adejuyigbe, Ebunoluwa Aderonke; Bee, Margaret Helen; Amare, Yared; Omotara, Babatunji Abayomi; Iganus, Ruth Buus; Manzi, Fatuma; Shamba, Donat Dominic; Skordis-Worrall, Jolene; Odebiyi, Adetanwa; Hill, Zelee Elizabeth

2015-10-14

Recommendations for care in the first week of a newborn's life include thermal care practices such as drying and wrapping, skin to skin contact, immediate breastfeeding and delayed bathing. This paper examines beliefs and practices related to neonatal thermal care in three African countries. Data were collected in the same way in each site and included 16-20 narrative interviews with recent mothers, eight observations of neonatal bathing, and in-depth interviews with 12-16 mothers, 9-12 grandmothers, eight health workers and 0-12 birth attendants in each site. We found similarities across sites in relation to understanding the importance of warmth, a lack of opportunities for skin to skin care, beliefs about the importance of several baths per day and beliefs that the Vernix caseosa was related to poor maternal behaviours. There was variation between sites in beliefs and practices around wrapping and drying after delivery, and the timing of the first bath with recent behavior change in some sites. There was near universal early bathing of babies in both Nigerian sites. This was linked to a deep-rooted belief about body odour. When asked about keeping the baby warm, respondents across the sites rarely mentioned recommended thermal care practices, suggesting that these are not perceived as salient. More effort is needed to promote appropriate thermal care practices both in facilities and at home. Programmers should be aware that changing deep rooted practices, such as early bathing in Nigeria, may take time and should utilize the current beliefs in the importance of neonatal warmth to facilitate behaviour change.

Plasma skin resurfacing: personal experience and long-term results.

Science.gov (United States)

Bentkover, Stuart H

2012-05-01

This article presents a comprehensive clinical approach to plasma resurfacing for skin regeneration. Plasma technology, preoperative protocols, resurfacing technique, postoperative care, clinical outcomes, evidence-based results, and appropriate candidates for this procedure are discussed. Specific penetration depth and specific laser energy measurements are provided. Nitrogen plasma skin regeneration is a skin-resurfacing technique that offers excellent improvement of mild to moderate skin wrinkles and overall skin rejuvenation. It also provides excellent improvement in uniformity of skin color and texture in patients with hyperpigmentation with Fitzpatrick skin types 1 through 4. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of thermal energy harvesting on the human - clothing - environment microsystem

Science.gov (United States)

Myers, A. C.; Jur, J. S.

2017-10-01

The objective of this work is to perform an in depth investigation of garment-based thermal energy harvesting. The effect of human and environmental factors on the working efficiency of a thermal energy harvesting devices, or a thermoelectric generator (TEG), placed on the body is explored.. Variables that strongly effect the response of the TEG are as follows: skin temperature, human motion or speed, body location, environmental conditions, and the textile properties surrounding the TEG. In this study, the use of textiles for managing thermal comfort of wearable technology and energy harvesting are defined. By varying the stitch length and/or knit structure, one can manipulate the thermal conductivity of the garment in a specific location. Another method of improving TEG efficiency is through the use of a heat spreader, which increases the effective collection area of heat on the TEG hot side. Here we show the effect of a TEG on the thermal properties of a garment with regard to two knit stitches, jersey and 1 × 1 rib.

Beyond the classic thermoneutral zone: Including thermal comfort.

Science.gov (United States)

Kingma, Boris Rm; Frijns, Arjan Jh; Schellen, Lisje; van Marken Lichtenbelt, Wouter D

2014-01-01

The thermoneutral zone is defined as the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced. That means that heat transport from body core to skin must equal heat transport from skin to the environment. This study focuses on what combinations of core and skin temperature satisfy the biophysical requirements of being in the thermoneutral zone for humans. Moreover, consequences are considered of changes in insulation and adding restrictions such as thermal comfort (i.e. driver for thermal behavior). A biophysical model was developed that calculates heat transport within a body, taking into account metabolic heat production, tissue insulation, and heat distribution by blood flow and equates that to heat loss to the environment, considering skin temperature, ambient temperature and other physical parameters. The biophysical analysis shows that the steady-state ambient temperature range associated with the thermoneutral zone does not guarantee that the body is in thermal balance at basal metabolic rate per se. Instead, depending on the combination of core temperature, mean skin temperature and ambient temperature, the body may require significant increases in heat production or heat loss to maintain stable core temperature. Therefore, the definition of the thermoneutral zone might need to be reformulated. Furthermore, after adding restrictions on skin temperature for thermal comfort, the ambient temperature range associated with thermal comfort is smaller than the thermoneutral zone. This, assuming animals seek thermal comfort, suggests that thermal behavior may be initiated already before the boundaries of the thermoneutral zone are reached.

Optimum Application of Thermal Factors to Artificial Neural Network Models for Improvement of Control Performance in Double Skin-Enveloped Buildings

Directory of Open Access Journals (Sweden)

Kyung-Il Chin

2013-08-01

Full Text Available This study proposes an artificial neural network (ANN-based thermal control method for buildings with double skin envelopes that has rational relationships between the ANN model input and output. The relationship between the indoor air temperature and surrounding environmental factors was investigated based on field measurement data from an actual building. The results imply that the indoor temperature was not significantly influenced by vertical solar irradiance, but by the outdoor and cavity temperature. Accordingly, a new ANN model developed in this study excluded solar irradiance as an input variable for predicting the future indoor temperature. The structure and learning method of this new ANN model was optimized, followed by the performance tests of a variety of internal and external envelope opening strategies for the heating and cooling seasons. The performance tests revealed that the optimized ANN-based logic yielded better temperature conditions than the non-ANN based logic. This ANN-based logic increased overall comfortable periods and decreased the frequency of overshoots and undershoots out of the thermal comfort range. The ANN model proved that it has the potential to be successfully applied in the temperature control logic for double skin-enveloped buildings. The ANN model, which was proposed in this study, effectively predicted future indoor temperatures for the diverse opening strategies. The ANN-based logic optimally determined the operation of heating and cooling systems as well as opening conditions for the double skin envelopes.

Effects of hair removal alexandrite laser on biometric parameters of the skin.

Science.gov (United States)

Alavi, Shiva; Abolhasani, Ehsan; Nilforoushzadeh, Mohammadali

2016-04-01

The effects of alexandrite laser (AL) on skin parameters such as melanin content, skin layer depth, elasticity, and density have not been investigated through biometric methods. We aim to assess the effect of AL on the skin parameters through biometric devices to determine whether it has positive effects on treated region. In this pretest-posttest study, we recruited patients who attended Laser Clinic of Skin and Stem Cell Research Center, Tehran University of Medical Sciences, Tehran, Iran, from January through December 2014. Patients had to be free of any dermatologic conditions and lesion at the site of treatment or any contraindication to laser therapy. Baseline measurements were performed and patients received four sessions of AL therapy (spot size, 12 mm; fluence, 12 J/cm(2); and pulse width, 5 Hz) with 4-week intervals. Four weeks after the last treatment session, the same parameters were assessed that included skin color, transepidermal water loss (TEWL), dermis and epidermis density and depth (through skin ultrasonography), melanin content, erythema intensity, and skin elasticity. Biometric parameters of 33 patients (27 females [81.8%]), with mean (SD) age of 35.7 (9.5) years were evaluated. The mean percent changes of skin parameters were as follows: skin color, 5.88% through Visioface and by 56.8% through Colorimeter devices (became lighter); melanin content, -15.95%; TEWL, -2.96%; elasticity, +14.88%; dermis depth -19.01%; and dermis density, +1580.11% (P < 0.001 for changes in each parameter). AL could decrease melanin content of the skin and make the skin thinner while it could increase elasticity and density of epidermis and dermis, which might indicate increased collagen content of skin.

Hand and goods judgment algorithm based on depth information

Science.gov (United States)

Li, Mingzhu; Zhang, Jinsong; Yan, Dan; Wang, Qin; Zhang, Ruiqi; Han, Jing

2016-03-01

A tablet computer with a depth camera and a color camera is loaded on a traditional shopping cart. The inside information of the shopping cart is obtained by two cameras. In the shopping cart monitoring field, it is very important for us to determine whether the customer with goods in or out of the shopping cart. This paper establishes a basic framework for judging empty hand, it includes the hand extraction process based on the depth information, process of skin color model building based on WPCA (Weighted Principal Component Analysis), an algorithm for judging handheld products based on motion and skin color information, statistical process. Through this framework, the first step can ensure the integrity of the hand information, and effectively avoids the influence of sleeve and other debris, the second step can accurately extract skin color and eliminate the similar color interference, light has little effect on its results, it has the advantages of fast computation speed and high efficiency, and the third step has the advantage of greatly reducing the noise interference and improving the accuracy.

Erbium:YAG laser resurfacing increases skin permeability and the risk of excessive absorption of antibiotics and sunscreens: the influence of skin recovery on drug absorption.

Science.gov (United States)

Lee, Woan-Ruoh; Shen, Shing-Chuan; Al-Suwayeh, Saleh A; Li, Yi-Ching; Fang, Jia-You

2012-06-01

While laser skin resurfacing is expected to result in reduced barrier function and increased risk of drug absorption, the extent of the increment has not yet been systematically investigated. We aimed to establish the skin permeation profiles of tetracycline and sunscreens after exposure to the erbium:yttrium-aluminum-garnet (Er:YAG) laser during postoperative periods. Physiological and histopathological examinations were carried out for 5 days after laser treatment on nude mice. Percutaneous absorption of the permeants was determined by an in vitro Franz cell. Ablation depths varied in reaching the stratum corneum (10 μm, 2.5 J/cm²) to approach the epidermis (25 μm, 6.25 J/cm²) and upper dermis (40 μm, 10 J/cm²). Reepithelialization evaluated by transepidermal water loss was complete within 2-4 days and depended on the ablation depth. Epidermal hyperplasia was observed in the 40-μm-treated group. The laser was sufficient to disrupt the skin barrier and allow the transport of the permeants into and across the skin. The laser fluence was found to play an important role in modulating skin absorption. A 25-μm ablation depth increased tetracycline flux 84-fold. A much smaller enhancement (3.3-fold) was detected for tetracycline accumulation within the skin. The laser with different fluences produced enhancement of oxybenzone skin deposition of 3.4-6.4-fold relative to the untreated group. No penetration across the skin was shown regardless of whether titanium dioxide was applied to intact or laser-treated skin. However, laser resurfacing increased the skin deposition of titanium dioxide from 46 to 109-188 ng/g. Tetracycline absorption had recovered to the level of intact skin after 5 days, while more time was required for oxybenzone absorption. The in vivo skin accumulation and plasma concentration revealed that the laser could increase tetracycline absorption 2-3-fold. The experimental results indicated that clinicians should be cautious when determining the

Polymer scaffolds with no skin-effect for tissue engineering applications fabricated by thermally induced phase separation

International Nuclear Information System (INIS)

Kasoju, Naresh; Kubies, Dana; Sedlačík, Tomáš; Kumorek, Marta M.; Rypáček, František; Janoušková, Olga; Koubková, Jana

2016-01-01

Thermally induced phase separation (TIPS) based methods are widely used for the fabrication of porous scaffolds for tissue engineering and related applications. However, formation of a less-/non-porous layer at the scaffold’s outer surface at the air–liquid interface, often known as the skin-effect, restricts the cell infiltration inside the scaffold and therefore limits its efficacy. To this end, we demonstrate a TIPS-based process involving the exposure of the just quenched poly(lactide-co-caprolactone):dioxane phases to the pure dioxane for a short time while still being under the quenching strength, herein after termed as the second quenching (2Q). Scanning electron microscopy, mercury intrusion porosimetry and contact angle analysis revealed a direct correlation between the time of 2Q and the gradual disappearance of the skin, followed by the widening of the outer pores and the formation of the fibrous filaments over the surface, with no effect on the internal pore architecture and the overall porosity of scaffolds. The experiments at various quenching temperatures and polymer concentrations revealed the versatility of 2Q in removing the skin. In addition, the in vitro cell culture studies with the human primary fibroblasts showed that the scaffolds prepared by the TIPS based 2Q process, with the optimal exposure time, resulted in a higher cell seeding and viability in contrast to the scaffolds prepared by the regular TIPS. Thus, TIPS including the 2Q step is a facile, versatile and innovative approach to fabricate the polymer scaffolds with a skin-free and fully open porous surface morphology for achieving a better cell response in tissue engineering and related applications. (paper)

Echosonography and surgical therapy of facial skin tumors

Directory of Open Access Journals (Sweden)

Pešić Zoran U.

2002-01-01

Full Text Available In the second half of the 20 century, echosonography has been used in many medical specialties. In 1992 and 1993 highfrequencies echosonography was used in the examination of irritant and allergic skin lesions in order to examine the effects of different therapeuthical agents on the skin lesions [1-4]. Hoffmann used highfrequencies echosonography in the examination of healing of skin lesions [3]. By their incidence skin tumors are the largest group of newly discovered tumors, and their usual location is on the face [5-7]. By clinical examination it is not possible to precisely determine the depth of tumor border; therefore, the radically performed surgical excision is the only correct surgical treatment. The aim of this study was to estimate the results of preoperatively performed high frequencies echosonography in order to reduce the number of incorrectly performed surgical excisions of skin tumors. The group was composed of 40 patients with 45 tumors, who first underwent echosonographic diagnostic procedure (20 MHz, Hadsund electronic, Hadsund Technology, Denmark and then surgical excision; patients in control group (45 patients with 45 tumors were only subjected to surgical excision. Excised tumors were then pathohistologically analyzed, and measurements of tumor depth progression were performed. Margins of pathohistological specimen were controlled for the presence of tumor cells. Results of measurements of tumor depth obtained by echosonography and pathohistological measurements were compared. By Jate's modification of c2 test results regarding correct and incorrect surgical excision in patients and control group were compared. By linear regression analysis results of tumor depth obtained by echosonographic and pathohistologic examinations were compared. Hypoechogen zone echosonographic results were used like criteria for tumor expansion. Results of tumor depth measurements are presented in Table 1. Linear regression analysis showed (R = 0

Penetration and delivery characteristics of repetitive microjet injection into the skin.

Science.gov (United States)

Römgens, Anne M; Rem-Bronneberg, Debbie; Kassies, Roel; Hijlkema, Markus; Bader, Dan L; Oomens, Cees W J; van Bruggen, Michel P B

2016-07-28

Drugs can be delivered transdermally using jet injectors, which can be an advantageous route compared to oral administration. However, these devices inject large volumes deep into the skin or tissues underneath the skin often causing bruising and pain. This may be prevented by injecting smaller volumes at lower depth in a repetitive way using a microjet injection device. Such a device could be used to apply drugs in a controllable and sustainable manner. However, the efficacy of microjet injection has been rarely examined. In this study, the penetration and delivery capacity was examined of a repetitive microjet injection device. Various experiments were performed on epidermal and full-thickness ex vivo human as well as ex vivo porcine skin samples. Results revealed that microjets with a velocity exceeding 90m/s penetrated an epidermal skin sample with a delivery efficiency of approximately 96%. In full-thickness human skin, the delivery efficiency drastically decreased to a value of approximately 12%. Experiments on full-thickness skin revealed that the microjets penetrated to a depth corresponding to the transition between the papillary and reticular dermis. This depth did not further increase with increasing number of microjets. In vivo studies on rats indicated that intact insulin was absorbed into the systemic circulation. Hence, the microjet injection device was able to deliver medication into the skin, although the drug delivery efficiency should be increased. Copyright © 2016 Elsevier B.V. All rights reserved.

Accurate laser skin perforation technique aimed at promoting bleeding and reducing pain

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Han-Chao Chang

2015-11-01

Full Text Available Laser skin perforation is an effective and promising technique for use in blood collection. In this study, the relation between the perforation profile of skin and laser irradiation at various energies is discussed. Increasing laser energy does not uniformly expand the size and depth of a hole because the shallow depth of field (DOF of the focused light primarily concentrates energy on the skin surface. In practice, the hole gradually transforms from a semielliptical shape to an upside-down avocado shape as the laser energy increases. This phenomenon can increase the amount of bleeding and reduce pain. The findings support the feasibility of developing an accurate laser skin perforation method.

London penetration depth and thermal fluctuations in the sulphur hydride 203 K superconductor

Energy Technology Data Exchange (ETDEWEB)

Talantsev, E.F.; Crump, W.P. [Robinson Research Institute, Victoria University of Wellington, Lower Hutt (New Zealand); Storey, J.G.; Tallon, J.L. [Robinson Research Institute, Victoria University of Wellington, Lower Hutt (New Zealand); MacDiarmid Institute for Advanced Materials and Nanotechnology, Lower Hutt (New Zealand)

2017-03-15

Recently, compressed H{sub 2}S has been shown to become superconducting at 203 K under a pressure of 155 GPa. One might expect fluctuations to dominate at such temperatures. Using the magnetisation critical current, we determine the ground-state London penetration depth, λ{sub 0} = 189 nm, and the superconducting energy gap, Δ{sub 0} = 27.8 meV, and find these parameters are similar to those of cuprate superconductors. We also determine the fluctuation temperature scale, T{sub fluc} = 1470 K, which shows that, unlike the cuprates, T{sub c} of the hydride is not limited by fluctuations. This is due to its three dimensionality and suggests the search for better superconductors should refocus on three-dimensional systems where the inevitable thermal fluctuations are less likely to reduce the observed T{sub c}. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Investigation of the shallow depth explosions

International Nuclear Information System (INIS)

Kamegai, M.

1976-01-01

An investigation of the nuclear explosions at shallow depth is made. A combination of an explosion code and an effects code proves to be an excellent tool for this study. A numerical simulation of ''Johnie Boy'' shows that the energy coupling to the air takes place in two stages; first by a rising mound, and then by a vented source. The thermal effects are examined for a 1 kt source at three depths of burial. The ''mushroom effect'' leaves a hot radiative plasma in the upper level and cold materials in the lower region of the debris. The temperature and the energy density of the debris can give an upper limit on the thermal output

Remotely sensed soil temperatures beneath snow-free skin-surface using thermal observations from tandem polar-orbiting satellites: An analytical three-time-scale model

DEFF Research Database (Denmark)

Zhan, Wenfeng; Zhou, Ji; Ju, Weimin

2014-01-01

Subsurface soil temperature is a key variable of land surface processes and not only responds to but also modulates the interactions of energy fluxes at the Earth's surface. Thermal remote sensing has traditionally been regarded as incapable of detecting the soil temperature beneath the skin-surf...

Hydrothermal alteration at the Roosevelt Hot Springs thermal area, Utah: Petrographic characterization of the alteration to 2 kilometers depth

Energy Technology Data Exchange (ETDEWEB)

Ballantyne, J.M.; Parry, W.T.

1978-04-01

Hydrothermal alteration in drill cuttings from Thermal Power drillhole 14-2, Roosevelt Hot Springs Thermal area, has been studied petrographically. The hole is sited in alluvium approximately 1.6 km southeast of the old Resort and was rotary drilled to a depth of 1866.0 m. The exact hole location is 2310 FNL, 350 FWL, Sec. 2, Twp 27S, Rge 9W, elevation 1908.5 m. Core was extracted from 792.5 to 795.5 m. Thin sections were made from samples at 15.2 m intervals of drill cuttings collected at 1.5 or 3.0 m intervals during drilling. Thin sections were made of 1.5 or 3.0 m intervals from 274.3 to 304.8 m, 487.9 to 581.2 m, and 868.7 to 899.2 m. These intervals were chosen for close spaced sampling on the basis of increases in temperature, porosity, conductivity and acoustic velocity shown in geophysical logs. A total of 153 thin sections of cuttings were made, and an additional 9 sections were made from the core. Depths of thin section samples are listed in the appendix. A visual estimate of the percentage of each rock type was made for each thin section.

Quantitative detection of caffeine in human skin by confocal Raman spectroscopy--A systematic in vitro validation study.

Science.gov (United States)

Franzen, Lutz; Anderski, Juliane; Windbergs, Maike

2015-09-01

For rational development and evaluation of dermal drug delivery, the knowledge of rate and extent of substance penetration into the human skin is essential. However, current analytical procedures are destructive, labor intense and lack a defined spatial resolution. In this context, confocal Raman microscopy bares the potential to overcome current limitations in drug depth profiling. Confocal Raman microscopy already proved its suitability for the acquisition of qualitative penetration profiles, but a comprehensive investigation regarding its suitability for quantitative measurements inside the human skin is still missing. In this work, we present a systematic validation study to deploy confocal Raman microscopy for quantitative drug depth profiling in human skin. After we validated our Raman microscopic setup, we successfully established an experimental procedure that allows correlating the Raman signal of a model drug with its controlled concentration in human skin. To overcome current drawbacks in drug depth profiling, we evaluated different modes of peak correlation for quantitative Raman measurements and offer a suitable operating procedure for quantitative drug depth profiling in human skin. In conclusion, we successfully demonstrate the potential of confocal Raman microscopy for quantitative drug depth profiling in human skin as valuable alternative to destructive state-of-the-art techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

Antecedent thermal injury worsens split-thickness skin graft quality: A clinically relevant porcine model of full-thickness burn, excision and grafting.

Science.gov (United States)

Carlsson, Anders H; Rose, Lloyd F; Fletcher, John L; Wu, Jesse C; Leung, Kai P; Chan, Rodney K

2017-02-01

Current standard of care for full-thickness burn is excision followed by autologous split-thickness skin graft placement. Skin grafts are also frequently used to cover surgical wounds not amenable to linear closure. While all grafts have potential to contract, clinical observation suggests that antecedent thermal injury worsens contraction and impairs functional and aesthetic outcomes. This study evaluates the impact of antecedent full-thickness burn on split-thickness skin graft scar outcomes and the potential mediating factors. Full-thickness contact burns (100°C, 30s) were created on the backs of anesthetized female Yorkshire Pigs. After seven days, burn eschar was tangentially excised and covered with 12/1000th inch (300μm) split-thickness skin graft. For comparison, unburned wounds were created by sharp excision to fat before graft application. From 7 to 120days post-grafting, planimetric measurements, digital imaging and biopsies for histology, immunohistochemistry and gene expression were obtained. At 120days post-grafting, the Observer Scar Assessment Scale, colorimetry, contour analysis and optical graft height assessments were performed. Twenty-nine porcine wounds were analyzed. All measured metrics of clinical skin quality were significantly worse (pskin graft quality, likely by multiple mechanisms including burn-related inflammation, microscopically inadequate excision, and dysregulation of tissue remodeling. A valid, reliable, clinically relevant model of full-thickness burn, excision and skin replacement therapy has been demonstrated. Future research to enhance quality of skin replacement therapies should be directed toward modulation of inflammation and assessments for complete excision. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

In vivo confocal Raman microscopic determination of depth profiles of the stratum corneum lipid organization influenced by application of various oils.

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Choe, ChunSik; Schleusener, Johannes; Lademann, Jürgen; Darvin, Maxim E

2017-08-01

The intercellular lipids (ICL) of stratum corneum (SC) play an important role in maintaining the skin barrier function. The lateral and lamellar packing order of ICL in SC is not homogenous, but rather depth-dependent. This study aimed to analyze the influence of the topically applied mineral-derived (paraffin and petrolatum) and plant-derived (almond oil and jojoba oil) oils on the depth-dependent ICL profile ordering of the SC in vivo. Confocal Raman microscopy (CRM), a unique tool to analyze the depth profile of the ICL structure non-invasively, is employed to investigate the interaction between oils and human SC in vivo. The results show that the response of SC to oils' permeation varies in the depths. All oils remain in the upper layers of the SC (0-20% of SC thickness) and show predominated differences of ICL ordering from intact skin. In these depths, skin treated with plant-derived oils shows more disordered lateral and lamellar packing order of ICL than intact skin (p0.1), except plant-derived oils at the depth 30% of SC thickness. In the deeper layers of the SC (60-100% of SC thickness), no difference between ICL lateral packing order of the oil-treated and intact skin can be observed, except that at the depths of 70-90% of the SC thickness, where slight changes with more disorder states are measured for plant-derived oil treated skin (p<0.1), which could be explained by the penetration of free fatty acid fractions in the deep-located SC areas. Both oil types remain in the superficial layers of the SC (0-20% of the SC thickness). Skin treated with mineral- and plant-derived oils shows significantly higher disordered lateral and lamellar packing order of ICL in these layers of the SC compared to intact skin. Plant-derived oils significantly changed the ICL ordering in the depths of 30% and 70-90% of the SC thickness, which is likely due to the penetration of free fatty acids in the deeper layers of the SC. Copyright © 2017 Japanese Society for

Multilayer detector for skin absorbed dose measuring

International Nuclear Information System (INIS)

Osanov, D.P.; Panova, V.P.; Shaks, A.I.

1985-01-01

A method for skin dosimetry based on utilization of multilayer detectors and permitting to estimate distribution of absorbed dose by skin depth is described. The detector represents a set of thin sensitive elements separated by tissue-equivalent absorbers. Quantitative evaluation and forecasting the degree of radiation injury of skin are determined by the formula based on determination of the probability of the fact that cells are not destroyed and they can divide further on. The given method ensures a possibility of quantitative evaluation of radiobiological effect and forecasting clinical consequences of skin irradiation by results of corresponding measurements of dose by means of the miultilayer detector

Human skin wetness perception: psychophysical and neurophysiological bases

Science.gov (United States)

Filingeri, Davide; Havenith, George

2015-01-01

The ability to perceive thermal changes in the surrounding environment is critical for survival. However, sensing temperature is not the only factor among the cutaneous sensations to contribute to thermoregulatory responses in humans. Sensing skin wetness (i.e. hygrosensation) is also critical both for behavioral and autonomic adaptations. Although much has been done to define the biophysical role of skin wetness in contributing to thermal homeostasis, little is known on the neurophysiological mechanisms underpinning the ability to sense skin wetness. Humans are not provided with skin humidity receptors (i.e., hygroreceptors) and psychophysical studies have identified potential sensory cues (i.e. thermal and mechanosensory) which could contribute to sensing wetness. Recently, a neurophysiological model of human wetness sensitivity has been developed. In helping clarifying the peripheral and central neural mechanisms involved in sensing skin wetness, this model has provided evidence for the existence of a specific human hygrosensation strategy, which is underpinned by perceptual learning via sensory experience. Remarkably, this strategy seems to be shared by other hygroreceptor-lacking animals. However, questions remain on whether these sensory mechanisms are underpinned by specific neuromolecular pathways in humans. Although the first study on human wetness perception dates back to more than 100 years, it is surprising that the neurophysiological bases of such an important sensory feature have only recently started to be unveiled. Hence, to provide an overview of the current knowledge on human hygrosensation, along with potential directions for future research, this review will examine the psychophysical and neurophysiological bases of human skin wetness perception. PMID:27227008

Complications of medium depth and deep chemical peels

Directory of Open Access Journals (Sweden)

Nanma Nikalji

2012-01-01

Full Text Available Superficial and medium depth peels are dynamic tools when used as part of office procedures for treatment of acne, pigmentation disorders, and photo-aging. Results and complications are generally related to the depth of wounding, with deeper peels providing more marked results and higher incidence of complications. Complications are also more likely with darker skin types, certain peeling agents, and sun exposure. They can range from minor irritations, uneven pigmentation to permanent scarring. In very rare cases, complications can be life-threatening.

Dye-enhanced laser welding for skin closure.

Science.gov (United States)

DeCoste, S D; Farinelli, W; Flotte, T; Anderson, R R

1992-01-01

The use of a laser to weld tissue in combination with a topical photosensitizing dye permits selective delivery of energy to the target tissue. A combination of indocyanine green (IG), absorption peak 780 nm, and the near-infrared (IR) alexandrite laser was studied with albino guinea pig skin. IG was shown to bind to the outer 25 microns of guinea pig dermis and appeared to be bound to collagen. The optical transmittance of full-thickness guinea pig skin in the near IR was 40% indicating that the alexandrite laser should provide adequate tissue penetration. Laser "welding" of skin in vivo was achieved at various concentrations of IG from 0.03 to 3 mg/cc using the alexandrite at 780 nm, 250-microseconds pulse duration, 8 Hz, and a 4-mm spot size. A spectrum of welds was obtained from 1- to 20-W/cm2 average irradiance. Weak welds occurred with no thermal damage obtained at lower irradiances: stronger welds with thermal damage confined to the weld site occurred at higher irradiances. At still higher irradiances, local vaporization occurred with failure to "weld." Thus, there was an optimal range of irradiances for "welding," which varied inversely with dye concentration. Histology confirmed the thermal damage results that were evident clinically. IG dye-enhanced laser welding is possible in skin and with further optimization may have practical application.

Analysis of the in vivo confocal Raman spectral variability in human skin

Science.gov (United States)

Mogilevych, Borys; dos Santos, Laurita; Rangel, Joao L.; Grancianinov, Karen J. S.; Sousa, Mariane P.; Martin, Airton A.

2015-06-01

Biochemical composition of the skin changes in each layer and, therefore, the skin spectral profile vary with the depth. In this work, in vivo Confocal Raman spectroscopy studies were performed at different skin regions and depth profile (from the surface down to 10 μm) of the stratum corneum, to verify the variability and reproducibility of the intra- and interindividual Raman data. The Raman spectra were collected from seven healthy female study participants using a confocal Raman system from Rivers Diagnostic, with 785 nm excitation line and a CCD detector. Measurements were performed in the volar forearm region, at three different points at different depth, with the step of 2 μm. For each depth point, three spectra were acquired. Data analysis included the descriptive statistics (mean, standard deviation and residual) and Pearson's correlation coefficient calculation. Our results show that inter-individual variability is higher than intraindividual variability, and variability inside the SC is higher than on the skin surface. In all these cases we obtained r values, higher than 0.94, which correspond to high correlation between Raman spectra. It reinforces the possibility of the data reproducibility and direct comparison of in vivo results obtained with different study participants of the same age group and phototype.

Phosphor-Doped Thermal Barrier Coatings Deposited by Air Plasma Spray for In-Depth Temperature Sensing

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Di Peng

2016-09-01

Full Text Available Yttria-stabilized zirconia (YSZ-based thermal barrier coating (TBC has been integrated with thermographic phosphors through air plasma spray (APS for in-depth; non-contact temperature sensing. This coating consisted of a thin layer of Dy-doped YSZ (about 40 µm on the bottom and a regular YSZ layer with a thickness up to 300 µm on top. A measurement system has been established; which included a portable; low-cost diode laser (405 nm; a photo-multiplier tube (PMT and the related optics. Coating samples with different topcoat thickness were calibrated in a high-temperature furnace from room temperature to around 900 °C. The results convincingly showed that the current sensor and the measurement system was capable of in-depth temperature sensing over 800 °C with a YSZ top layer up to 300 µm. The topcoat thickness was found to have a strong effect on the luminescent signal level. Therefore; the measurement accuracy at high temperatures was reduced for samples with thick topcoats due to strong light attenuation. However; it seemed that the light transmissivity of YSZ topcoat increased with temperature; which would improve the sensor’s performance at high temperatures. The current sensor and the measurement technology have shown great potential in on-line monitoring of TBC interface temperature.

Human skin penetration of silver nanoparticles through intact and damaged skin

International Nuclear Information System (INIS)

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

2009-01-01

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 μg/cm 2 of silver nanoparticles coated with polyvinylpirrolidone dispersed in synthetic sweat were applied as donor phase to the outer surface of the skin for 24 h. 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 -2 (range 0.43-11.6) were found in the receiving solutions of cells where the nanoparticles solution was applied on intact 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 <1 h. 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

The effect of repeated laser stimuli to ink-marked skin on skin temperature—recommendations for a safe experimental protocol in humans

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Victoria J. Madden

2016-01-01

Full Text Available Background. Nd:YAP laser is widely used to investigate the nociceptive and pain systems, generating perpetual and laser-evoked neurophysiological responses. A major procedural concern for the use of Nd:YAP laser stimuli in experimental research is the risk of skin damage. The absorption of Nd:YAP laser stimuli is greater in darker skin, or in pale skin that has been darkened with ink, prompting some ethics boards to refuse approval to experimenters wishing to track stimulus location by marking the skin with ink. Some research questions, however, require laser stimuli to be delivered at particular locations or within particular zones, a requirement that is very difficult to achieve if marking the skin is not possible. We thoroughly searched the literature for experimental evidence and protocol recommendations for safe delivery of Nd:YAP laser stimuli over marked skin, but found nothing.Methods. We designed an experimental protocol to define safe parameters for the use of Nd:YAP laser stimuli over skin that has been marked with black dots, and used thermal imaging to assess the safety of the procedure at the forearm and the back.Results. Using thermal imaging and repeated laser stimulation to ink-marked skin, we demonstrated that skin temperature did not increase progressively across the course of the experiment, and that the small change in temperature seen at the forearm was reversed during the rest periods between blocks. Furthermore, no participant experienced skin damage due to the procedure.Conclusion. This protocol offers parameters for safe, confident and effective experimentation using repeated Nd:YAP laser on skin marked with ink, thus paving the way for investigations that depend on it.

Laser heat stimulation of tiny skin areas adds valuable information to quantitative sensory testing in postherpetic neuralgia.

Science.gov (United States)

Franz, Marcel; Spohn, Dorothee; Ritter, Alexander; Rolke, Roman; Miltner, Wolfgang H R; Weiss, Thomas

2012-08-01

Patients suffering from postherpetic neuralgia often complain about hypo- or hypersensation in the affected dermatome. The loss of thermal sensitivity has been demonstrated by quantitative sensory testing as being associated with small-fiber (Aδ- and C-fiber) deafferentation. We aimed to compare laser stimulation (radiant heat) to thermode stimulation (contact heat) with regard to their sensitivity and specificity to detect thermal sensory deficits related to small-fiber dysfunction in postherpetic neuralgia. We contrasted detection rate of laser stimuli with 5 thermal parameters (thresholds of cold/warm detection, cold/heat pain, and sensory limen) of quantitative sensory testing. Sixteen patients diagnosed with unilateral postherpetic neuralgia and 16 age- and gender-matched healthy control subjects were tested. Quantitative sensory testing and laser stimulation of tiny skin areas were performed in the neuralgia-affected skin and in the contralateral homologue of the neuralgia-free body side. Across the 5 thermal parameters of thermode stimulation, only one parameter (warm detection threshold) revealed sensory abnormalities (thermal hypoesthesia to warm stimuli) in the neuralgia-affected skin area of patients but not in the contralateral area, as compared to the control group. In contrast, patients perceived significantly less laser stimuli both in the affected skin and in the contralateral skin compared to controls. Overall, laser stimulation proved more sensitive and specific in detecting thermal sensory abnormalities in the neuralgia-affected skin, as well as in the control skin, than any single thermal parameter of thermode stimulation. Thus, laser stimulation of tiny skin areas might be a useful diagnostic tool for small-fiber dysfunction. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Regional thermal comfort zone in males and females.

Science.gov (United States)

Ciuha, Ursa; Mekjavic, Igor B

2016-07-01

Skin regions differ in their sensitivity to temperature stimuli. The present study examined whether such regional differences were also evident in the perception of thermal comfort. Regional thermal comfort was assessed in males (N=8) and females (N=8), by having them regulate the temperature of the water delivered to a water-perfused suit (WPS), within a temperature range considered thermally comfortable. In separate trials, subjects regulated the temperature of the WPS, or specific regions of the suit covering different skin areas (arms, legs, front torso and back torso). In the absence of subjective temperature regulation (TR), the temperature changed in a sinusoidal manner from 10°C to 50°C; by depressing a switch and reversing the direction of the temperature at the limits of the thermal comfort zone (TCZ), each subject defined TCZ for each body region investigated. The range of regulated temperatures did not differ between genders and skin regions. Local Tsk at the lower and upper limits of the TCZ was similar for both genders. Higher (pthermally comfortable conditions, the well-established regional differences in thermosensitivity are not reflected in the TCZ, with similar temperature preferences by both genders. Thermal comfort of different skin regions and overall body is not achieved at a single skin temperature, but at range of temperatures, defined as the TCZ. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of techniques for the measurement of skin temperature during exercise in a hot, humid environment

Directory of Open Access Journals (Sweden)

Brian K McFarlin

2014-10-01

Full Text Available Exercising or working in a hot, humid environment can results in the onset of heat-related illness when an individual’s temperature is not carefully monitored. The purpose of the present study was to compare three techniques (data loggers, thermal imaging, and wired electrodes for the measurement of peripheral (bicep and central (abdominal skin temperature. Young men and women (N=30 were recruited to complete the present study. The three skin temperature measurements were made at 0 and every 10-min during 40-min (60% VO 2 max of cycling in a hot (39±2°C, humid (45±5% RH environment. Data was statistically analyzed using the Bland-Altman method and correlation analysis. For abdominal skin temperature, the Bland-Altman limits of agreement indicated that data loggers (1.5 were a better index of wired than was thermal imaging (3.5, For the bicep skin temperature the limits of agreement was similar between data loggers (1.9 and thermal (1.9, suggesting the both were suitable measurements. We also found that when skin temperature exceeded 35ºC, we observed progressively better prediction between data loggers, thermal imaging, and wired skin sensors. This report describes the potential for the use of data loggers and thermal imaging to be used as alternative measures of skin temperature in exercising, human subjects

Penile Inversion Vaginoplasty with or without Additional Full-Thickness Skin Graft: To Graft or Not to Graft?

Science.gov (United States)

Buncamper, Marlon E; van der Sluis, Wouter B; de Vries, Max; Witte, Birgit I; Bouman, Mark-Bram; Mullender, Margriet G

2017-03-01

Penile inversion vaginoplasty is considered to be the gold standard for gender reassignment surgery in transgender women. The use of additional full-thickness skin graft as neovaginal lining is controversial. Some believe that having extra penile skin for the vulva gives better aesthetic results. Others believe that it gives inferior functional results because of insensitivity and skin graft contraction. Transgender women undergoing penile inversion vaginoplasty were studied prospectively. The option to add full-thickness skin graft is offered in patients where the penile skin length lies between 7 and 12 cm. Neovaginal depth was measured at surgery and during follow-up (3, 13, 26, and 52 weeks postoperatively). Satisfaction with the aesthetic result, neovaginal depth, and dilation regimen during follow-up were recorded. Satisfaction, sexual function, and genital self-image were assessed using questionnaires. A total of 100 patients were included (32 with and 68 without additional full-thickness skin graft). Patient-reported aesthetic outcome, overall satisfaction with the neovagina, sexual function, and genital self-image were not significantly associated with surgical technique. The mean intraoperative neovaginal depth was 13.8 ± 1.4 cm. After 1 year, this was 11.5 ± 2.5 cm. The largest decline (-15 percent) in depth is observed in the first 3 postoperative weeks (p skin graft use, in penile inversion vaginoplasty. The additional use of full-thickness skin graft does not influence neovaginal shrinkage, nor does it affect the patient- and physician-reported aesthetic or functional outcome. Therapeutic, IV.

Plasma heating by ultrashort laser pulse in the regime of anomalous skin-effect

International Nuclear Information System (INIS)

Gamaly, E.G.; Kiselev, A.E.; Tikhonchuk, V.T.

1991-01-01

The problem of interaction of short laser pulse (light frequency ω 0 pulse duration, τ s /V Ti ; 1 s , skin depth, V Ti , ion velocity) with dense (ω 0 much-lt ω pe ) semi-infinite plasm was solved. The authors formulated the self-consistent problem of obtaining the electron distribution function and space dependence of electric field in skin layer, and solved the problem for the case of absence of the energy losses from the skin layer. The authors found self-similar nonstationary electron distribution function and space dependence of electric field in this case, and basing on these solutions, have calculated mean electron energy, absorption coefficient, bremsstrahlung radiation, time dependent skin depth. This paper discusses the limitations of our theory

Optical coherence tomography applied to tests of skin care products in humans--a case study.

Science.gov (United States)

Vasquez-Pinto, L M C; Maldonado, E P; Raele, M P; Amaral, M M; de Freitas, A Z

2015-02-01

When evaluating skin care products for human skin, quantitative test methods need to be simple, precise and reliable. Optical coherence tomography (OCT), provides high-resolution sectional images of translucent materials to a depth of a few millimeters, a technique usually applied to medical measurements in ophthalmology and dermatology. This study aimed to demonstrate the application of OCT as the main technique for monitoring changes in skin topography during tests of a wrinkle-reduction product in humans. We used a commercial OCT apparatus to perform clinical examinations of skin roughness in treated and non-treated sites in the periorbital region of thirty human voluntaries who were using an anti-aging product commercially available: Natura Chronos® Flavonóides de Passiflora 45+ FPS15, from Natura Cosméticos, Brazil. Measurements were performed days 0, 7, 14 and 28 of treatment. Equipment and software allowed real-time recording of skin roughness parameters and wrinkle depths. The OCT measurements have allowed the monitoring of changes in skin roughness, which have shown reduction in treated sites around 10%. The obtained depth distributions also indicate reduction in the occurrence of wrinkles deeper than 170 μm. The verified results are consistent with those typically obtained after successful treatment with modern anti-aging products. By using the OCT technique, it was possible to quantify changes in skin roughness and in the distribution of depths of skin wrinkles, with adequate sensitivity. OCT imaging allows the direct visualization of the skin topography with resolution of micrometers, a reliable and interactive tool for clinical use. Therefore, for the first time, we demonstrated the use of OCT technique to verify the efficacy of cosmetic products in real time. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Thermal comfort following immersion.

Science.gov (United States)

Guéritée, Julien; Redortier, Bernard; House, James R; Tipton, Michael J

2015-02-01

Unlike thermal comfort in air, little research has been undertaken exploring thermal comfort around water sports. We investigated the impact of swimming and cooling in air after swimming on thermal comfort. After 10 min of swimming-and-resting cycles in 28°C water, volunteers wearing two types of garments or in swim briefs, faced winds in 24°C air, at rest or when stepping. Thermal comfort was significantly higher during swimming than resting. Post-immersion, following maximum discomfort, in 45 of 65 tests thermal comfort improved although mean skin temperature was still cooling (0.26 [SD 0.19] °C·min(-1) - max was 0.89°C·min(-1)). When thermal comfort was re-established mean skin temperature was lower than at maximal discomfort in 39 of 54 tests (0.81 [SD 0.58] °C - max difference was 2.68°C). The reduction in thermal discomfort in this scenario could be due to the adaptation of thermoreceptors, or to reductions in cooling rates to levels where discomfort was less stimulated. The relief from the recent discomfort may explain why, later, thermal comfort returned to initial levels in spite of poorer thermal profiles. Copyright © 2014 Elsevier Inc. All rights reserved.

Dose factors for contamination of skin and clothing

International Nuclear Information System (INIS)

Henrichs, K.; Eiberweiser, C.; Paretzke, H.G.

1985-11-01

Methods are described for quantifying the radiation dose administered through radioactive contamination of the skin (and of clothing, in an approximative manner). The calculated results are presented in tables. The dose values established are of significance with regard to radiological assessment of contamination for the definition of dose limits, and for use as a criterion to select appropriate decontamination activities. Alpha, beta and monoenergetic electrons are of importance for estimating the absorbed dose in various skin depths, whereas for other body regions (as e.g. body organs) photon radiation has to be considered. The calculations are based on the assumption of homogeneous exposure of the skin, with the linear extension being large compared to the range of the emitted particle radiation. In order to be able to take into account potential penetration of radioactivity into deeper skin layers by diffusion or solution processes, the calculations have been made for contamination into various depths of the horny layers of the epidermis. The scheme of specific absorbed fraction (SAF) served as a basis for the uniform treatment of different radiation types for the calculation of dose values. (orig./HP) [de

A new polarized neutrons method for studying depth-inhomogeneously magnetized magnetic films

International Nuclear Information System (INIS)

Korneev, D.A.

1990-01-01

The main specific features of the process of polarized thermal neutrons specular reflection from the surface of depth-inhomogeneously magnetic films are considered theoretically. It is shown how using the method of specular reflection of polarized thermal neutrons from such a films surface, one may restore the depth distribution of the local magnetization vector M-vector(z). 9 refs

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

Science.gov (United States)

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

2010-07-01

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

Protective Skins for Composite Airliners

Science.gov (United States)

Johnson, Vicki S.; Boone, Richard L.; Jones, Shannon; Pendse, Vandana; Hayward, Greg

2014-01-01

Traditional composite aircraft structures are designed for load bearing and then overdesigned for impact damage and hot humid environments. Seeking revolutionary improvement in the performance and weight of composite structures, Cessna Aircraft Company, with sponsorship from the NASA Fundamental Aeronautics Program/Subsonic Fixed Wing Project, has developed and tested a protective skin concept which would allow the primary composite structure to carry only load and would meet the impact, hot and humid, and other requirements through protective skins. A key requirement for the protective skins is to make any impact damage requiring repair visible. Testing from the first generation of skins helped identify the most promising materials which were used in a second generation of test articles. This report summarizes lessons learned from the first generation of protective skins, the design and construction of the second-generation test articles, test results from the second generation for impact, electromagnetic effects, aesthetics and smoothing, thermal, and acoustic (for the first time), and an assessment of the feasibility of the protective skin concept.

Hydrogel-forming microneedles increase in volume during swelling in skin, but skin barrier function recovery is unaffected

Science.gov (United States)

Donnelly, Ryan F.; Mooney, Karen; McCrudden, Maelíosa T.C.; Vicente-Pérez, Eva M.; Belaid, Luc; González-Vázquez, Patricia; McElnay, James C.; Woolfson, A. David

2014-01-01

We describe, for the first time, quantification of in-skin swelling and fluid uptake by hydrogel-forming microneedle arrays (MN) and skin barrier recovery in human volunteers. Such MN, prepared from aqueous blends of hydrolysed poly(methylvinylether/maleicanhydride) (15% w/w) and the crosslinker poly(ethyleneglycol) 10,000 daltons (7.5% w/w), were inserted into the skin of human volunteers (n = 15) to depths of approximately 300 μm by gentle hand pressure. The MN swelled in skin, taking up skin interstitial fluid, such that their mass had increased by approximately 30% after 6 hours in skin. Importantly, however, skin barrier function recovered within 24 hours post microneedle removal, regardless of how long the MN had been in skin or how much their volume had increased with swelling. Further research on closure of MN-induced micropores is required, since transepidermal water loss measurements suggested micropore closure, while optical coherence tomography indicated that MN-induced micropores had not closed over, even 24 hours after MN had been removed. There were no complaints of skin reactions, adverse events or strong views against MN use by any of the volunteers. Only some minor erythema was noted after patch removal, although this always resolved within 48 hours and no adverse events were present on follow-up. PMID:24633895

Greenhouse effect in double-skin facade

Energy Technology Data Exchange (ETDEWEB)

Gratia, E.; Herde, A. de [Universite Catholique de Louvain, Architecture et Climat, Louvain-La-Neuve (Belgium)

2007-02-15

In these last years, a great deal of interest has been devoted to double-skin facades due to the advantages claimed by this technology (in terms of energy saving in the cold season, high-tech image, protection from external noise and wind loads). One of the great characteristics of the double-skin facade is the greenhouse effect. We identify the factors that influence the greenhouse effect. The identified parameters are solar radiation level, orientation and shading devices use, opaque wall/window proportion of the interior facade, wind speed, colour of shading devices and of interior facade, depth of the cavity of the double-skin, glazing type in the interior facade and openings in the double-skin. We analyze the impact of these parameters on the mean air temperature evolution in the cavity. After that analyse, the article answers the question: is greenhouse effect favourable? The answer is moderate according to the double-skin orientation. (author)

Electroosmotic pore transport in human skin.

Science.gov (United States)

Uitto, Olivia D; White, Henry S

2003-04-01

To determine the pathways and origin of electroosmotic flow in human skin. Iontophoretic transport of acetaminophen in full thickness human cadaver skin was visualized and quantified by scanning electrochemical microscopy. Electroosmotic flow in the shunt pathways of full thickness skin was compared to flow in the pores of excised stratum corneum and a synthetic membrane pore. The penetration of rhodamine 6G into pore structures was investigated by laser scanning confocal microscopy. Electroosmotic transport is observed in shunt pathways in full thickness human skin (e.g., hair follicles and sweat glands), but not in pore openings of freestanding stratum corneum. Absolute values of the diffusive and iontophoretic pore fluxes of acetaminophen in full thickness human skin are also reported. Rhodamine 6G is observed to penetrate to significant depths (approximately 200 microm) along pore pathways. Iontophoresis in human cadaver skin induces localized electroosmotic flow along pore shunt paths. Electroosmotic forces arise from the passage of current through negatively charged mesoor nanoscale pores (e.g., gap functions) within cellular regions that define the pore structure beneath the stratum corneum.

Skin optical clearing for improvement of laser tattoo removal

Science.gov (United States)

Bashkatov, A. N.; Genina, E. A.; Tuchin, V. V.; Altshuler, G. B.

2009-06-01

The possibility of improvement of laser tattoo removal due to the optical clearing of human skin is investigated. It is shown experimentally that previously perforation of skin stratum corneum allows increasing tattoo image contrast at topical administration of immersion agent in contrast with non-perforated skin. Computer Monte Carlo simulation shows that at the optical clearing of upper skin layers the tattoo image contrast and the photon fraction absorbed in the tattoo area at the depths of 0.5 or 1.0 mm increase, that allows significant decreasing of the power of laser radiation used at laser thermolysis.

An antiaging skin care system containing alpha hydroxy acids and vitamins improves the biomechanical parameters of facial skin.

Science.gov (United States)

Tran, Diana; Townley, Joshua P; Barnes, Tanya M; Greive, Kerryn A

2015-01-01

The demand for antiaging products has dramatically increased in recent years, driven by an aging population seeking to maintain the appearance of youth. This study investigates the effects of an antiaging skin care system containing alpha hydroxy acids (AHAs) in conjunction with vitamins B3, C, and E on the biomechanical parameters of facial skin. Fifty two volunteers followed an antiaging skin care regimen comprising of cleanser, eye cream, day moisturizer, and night moisturizer for 21 days. Wrinkle depth (Ry ) and skin roughness (Ra ) were measured by skin surface profilometry of the crow's feet area, and skin elasticity parameters R2 (gross elasticity), R5 (net elasticity), R6 (viscoelastic portion), and R7 (recovery after deformation) were determined for facial skin by cutometer, preapplication and after 7, 14, and 21 days. Volunteers also completed a self-assessment questionnaire. Compared to baseline, Ry and Ra significantly improved by 32.5% (Pskin care treatment. These results were observed by the volunteers with 9 out of 10 discerning an improvement in skin texture and smoothness. Compared to baseline, R2 and R5 significantly increased by 15.2% (Pskin care system containing AHAs and vitamins significantly improves the biomechanical parameters of the skin including wrinkles and skin texture, as well as elasticity without significant adverse effects.

CALCULATED TEMPERATURE RISE AND THERMAL ELONGATION OF STRUCTURAL COMPONENTS, DEPENDING ON ACTION INTEGRAL OF INJECTED LIGHTNING CURRENTS

DEFF Research Database (Denmark)

Madsen, Søren Find

2005-01-01

expressions established, accounts for the geometry of the structure (round conductor, rectangular cross section, pipe, plane sheet, etc), the material properties (Aluminum, Copper, Carbon Fiber Composites, etc.), the frequency of the current (skin depth) and the Specific Energy (Action Integral). For linear...... structures (wires, bars etc.), the result is the resistance of the structure, the final temperature, and the thermal elongation depending on geometry and material properties. Regarding arc injection in the centre of plane specimens the equations enables calculation of the temperature as a function...

In vitro investigation of the follicular penetration of porcine ear skin using a nanoparticle-emulsion containing the antiseptic polihexanide In vitro investigation of the follicular penetration of porcine ear skin

Science.gov (United States)

Ulmer, M.; Patzelt, A.; Vergou, T.; Lademann, J.; Richter, H.; Kramer, A.; Müller, G.; Sterry, W.; Lange-Asschenfeldt, B.

2012-05-01

Earlier investigations regarding the distribution of the bacterial flora on the human skin demonstrate that the hair follicle acts as a bacterial reservoir, providing a quick source for secondary recontamination. These findings highlight the importance of the hair follicle as a target for modern antiseptics. In the present study, we have assessed the follicular penetration of a curcumin-labeled particle-associated antiseptic into porcine skin by laser scanning microscopy. Therefore, the follicular penetration depth of the curcumin-labeled particle-associated antiseptic was compared to the follicular penetration depth of curcumin-labeled particles without antiseptic. The investigation was performed in vitro using porcine skin biopsies. By superposition of the images acquired in the transmission and the fluorescent modus, it was possible to visualize the distribution of the fluorescent dye inside the hair follicles. Quantitative and qualitative results showed that both dispersions penetrated efficiently into the hair follicles. The average penetration depth of the particles with attached antiseptic polihexanide was significantly higher than that of particles without the attached antiseptic. Also, whilst very little sample preparation was needed, laser scanning microscopy was found to be an efficient tool to visualize the skin relief and in particular the hair follicle shaft and localize fluorescent markers within the skin tissue and hair follicles.

Fractional laser microablation of skin aimed at enhancing its permeability for nanoparticles

International Nuclear Information System (INIS)

Genina, Elina A; Dolotov, L E; Bashkatov, A N; Terentyuk, G S; Maslyakova, G N; Zubkina, E A; Tuchin, Valerii V; Yaroslavsky, I V; Altshuler, G B

2011-01-01

A new method for delivering nanoparticles into the skin using the fractional laser microablation of its surface and the ultrasonic treatment is proposed. As a result of in vitro and in vivo studies, it is shown that the 290-nm laser pulses with the energy from 0.5 to 3.0 J provide the penetration of nanoparticles of titanium dioxide with the diameter ∼100 nm from the skin surface to the depth, varying from 150 to 400 μm. Histological testing of the skin areas, subjected to the treatment, shows that the particles stay in the dermis at the depth up to 400 μm no less than for three weeks. (optical technologies in biophysics and medicine)

Characterizing human skin blood flow regulation in response to different local skin temperature perturbations

NARCIS (Netherlands)

Wu, Y.; Nieuwenhoff, M.D.; Huygen, Frank J.P.M.; van der Helm, F. C.T.; Niehof, S.P.; Schouten, A. C.

2017-01-01

Small nerve fibers regulate local skin blood flow in response to local thermal perturbations. Small nerve fiber function is difficult to assess with classical neurophysiological tests. In this study, a vasomotor response model in combination with a heating protocol was developed to quantitatively

Opto-thermal transient emission radiometry for rapid, non-destructive and non-contact determination of hydration and hydration depth profile in the skin of a grape

NARCIS (Netherlands)

Guo, X.; Bicanic, D.D.; Keijser, K.; Imhof, R.

2003-01-01

.The concept of optothermal transient emission radiometry at a wavelength of 2.94 µm was applied to non-destructively determine the level of hydration and the profile of hydration in the skin of intact fresh grapes taken from top and bottom sections of the same bunch.

Contribution of human skin topography to the characterization of dynamic skin tension during senescence: morpho-mechanical approach

Science.gov (United States)

Zahouani, H.; Djaghloul, M.; Vargiolu, R.; Mezghani, S.; Mansori, M. E. L.

2014-03-01

The structuring of the dermis with a network of collagen and elastic fibres gives a three-dimensional structure to the skin network with directions perpendicular and parallel to the skin surface. This three-dimensional morphology prints on the surface of the stratum corneum a three dimensional network of lines which express the mechanical tension of the skin at rest. To evaluate the changes of skin morphology, we used a three-dimensional confocal microscopy and characterization of skin imaging of volar forearm microrelief. We have accurately characterize the role of skin line network during chronological aging with the identification of depth scales on the network of lines (z 60 microns). During aging has been highlighted lower rows for elastic fibres, the decrease weakened the tension and results in enlargement of the plates of the microrelief, which gives us a geometric pertinent indicator to quantify the loss of skin tension and assess the stage of aging. The study of 120 Caucasian women shows that ageing in the volar forearm zone results in changes in the morphology of the line network organisation. The decrease in secondary lines (z 60 μm) and an accentuation of the anisotropy index.

Use of multiphoton tomography and fluorescence lifetime imaging to investigate skin pigmentation in vivo

Science.gov (United States)

Dancik, Yuri; Favre, Amandine; Loy, Chong Jin; Zvyagin, Andrei V.; Roberts, Michael S.

2013-02-01

There is a growing body of literature showing the usefulness of multiphoton tomography (MPT) and fluorescence lifetime imaging for in situ characterization of skin constituents and the ensuing development of noninvasive diagnostic tools against skin diseases. Melanin and pigmentation-associated skin cancers constitute some of the major applications. We show that MPT and fluorescence lifetime imaging can be used to measure changes in cutaneous melanin concentration and that these can be related to the visible skin color. Melanin in the skin of African, Indian, Caucasian, and Asian volunteers is detected on the basis of its emission wavelength and fluorescence lifetimes in solution and in a melanocyte-keratinocyte cell culture. Fluorescence intensity is used to characterize the melanin content and distribution as a function of skin type and depth into the skin (stratum granulosum and stratum basale). The measured fluorescence intensities in given skin types agree with melanin amounts reported by others using biopsies. Our results suggest that spatial distribution of melanin in skin can be studied using MPT and fluorescence lifetime imaging, but further studies are needed to ascertain that the method can resolve melanin amount in smaller depth intervals.

Diffuse reflectance imaging for non-melanoma skin cancer detection using laser feedback interferometry

Science.gov (United States)

Mowla, Alireza; Taimre, Thomas; Lim, Yah L.; Bertling, Karl; Wilson, Stephen J.; Prow, Tarl W.; Soyer, H. P.; Rakić, Aleksandar D.

2016-04-01

We propose a compact, self-aligned, low-cost, and versatile infrared diffuse-reflectance laser imaging system using a laser feedback interferometry technique with possible applications in in vivo biological tissue imaging and skin cancer detection. We examine the proposed technique experimentally using a three-layer agar skin phantom. A cylindrical region with a scattering rate lower than that of the surrounding normal tissue was used as a model for a non-melanoma skin tumour. The same structure was implemented in a Monte Carlo computational model. The experimental results agree well with the Monte Carlo simulations validating the theoretical basis of the technique. Results prove the applicability of the proposed technique for biological tissue imaging, with the capability of depth sectioning and a penetration depth of well over 1.2 mm into the skin phantom.

Monte Carlo skin dose simulation in intraoperative radiotherapy of breast cancer using spherical applicators

Science.gov (United States)

Moradi, F.; Ung, N. M.; Khandaker, M. U.; Mahdiraji, G. A.; Saad, M.; Malik, R. Abdul; Bustam, A. Z.; Zaili, Z.; Bradley, D. A.

2017-08-01

The relatively new treatment modality electronic intraoperative radiotherapy (IORT) is gaining popularity, irradiation being obtained within a surgically produced cavity being delivered via a low-energy x-ray source and spherical applicators, primarily for early stage breast cancer. Due to the spatially dramatic dose-rate fall off with radial distance from the source and effects related to changes in the beam quality of the low keV photon spectra, dosimetric account of the Intrabeam system is rather complex. Skin dose monitoring in IORT is important due to the high dose prescription per treatment fraction. In this study, modeling of the x-ray source and related applicators were performed using the Monte Carlo N-Particle transport code. The dosimetric characteristics of the model were validated against measured data obtained using an ionization chamber and EBT3 film as dosimeters. By using a simulated breast phantom, absorbed doses to the skin for different combinations of applicator size (1.5-5 cm) and treatment depth (0.5-3 cm) were calculated. Simulation results showed overdosing of the skin (>30% of prescribed dose) at a treatment depth of 0.5 cm using applicator sizes larger than 1.5 cm. Skin doses were significantly increased with applicator size, insofar as delivering 12 Gy (60% of the prescribed dose) to skin for the largest sized applicator (5 cm diameter) and treatment depth of 0.5 cm. It is concluded that the recommended 0.5-1 cm distance between the skin and applicator surface does not guarantee skin safety and skin dose is generally more significant in cases with the larger applicators. Highlights: • Intrabeam x-ray source and spherical applicators were simulated and skin dose was calculated. • Skin dose for constant skin to applicator distance strongly depends on applicator size. • Use of larger applicators generally results in higher skin dose. • The recommended 0.5-1 cm skin to applicator distance does not guarantee skin

Quantitative subsurface analysis using frequency modulated thermal wave imaging

Science.gov (United States)

Subhani, S. K.; Suresh, B.; Ghali, V. S.

2018-01-01

Quantitative depth analysis of the anomaly with an enhanced depth resolution is a challenging task towards the estimation of depth of the subsurface anomaly using thermography. Frequency modulated thermal wave imaging introduced earlier provides a complete depth scanning of the object by stimulating it with a suitable band of frequencies and further analyzing the subsequent thermal response using a suitable post processing approach to resolve subsurface details. But conventional Fourier transform based methods used for post processing unscramble the frequencies with a limited frequency resolution and contribute for a finite depth resolution. Spectral zooming provided by chirp z transform facilitates enhanced frequency resolution which can further improves the depth resolution to axially explore finest subsurface features. Quantitative depth analysis with this augmented depth resolution is proposed to provide a closest estimate to the actual depth of subsurface anomaly. This manuscript experimentally validates this enhanced depth resolution using non stationary thermal wave imaging and offers an ever first and unique solution for quantitative depth estimation in frequency modulated thermal wave imaging.

Multiphoton spectroscopy of human skin in vivo

Science.gov (United States)

Breunig, Hans G.; Weinigel, Martin; König, Karsten

2012-03-01

In vivo multiphoton-intensity images and emission spectra of human skin are reported. Optical sections from different depths of the epidermis and dermis have been measured with near-infrared laser-pulse excitation. While the intensity images reveal information on the morphology, the spectra show emission characteristics of main endogenous skin fluorophores like keratin, NAD(P)H, melanin, elastin and collagen as well as of second harmonic generation induced by the excitation-light interaction with the dermal collagen network.

Probe depth matters in dermal microdialysis sampling of benzoic acid after topical application

DEFF Research Database (Denmark)

Holmgaard, R; Benfeldt, E; Bangsgaard, N

2012-01-01

-2 mm) and deep (>2 mm) positioning of the linear MD probe in the dermis of human abdominal skin, followed by topical application of 4 mg/ml of benzoic acid (BA) in skin chambers overlying the probes. Dialysate was sampled every hour for 12 h and analysed for BA content by high-performance liquid...... chromatography. Probe depth was measured by 20-MHz ultrasound scanning. The area under the time-versus-concentration curve (AUC) describes the drug exposure in the tissue during the experiment and is a relevant parameter to compare for the 3 dermal probe depths investigated. The AUC(0-12) were: superficial...... significantly different from each other (p value paper demonstrates that there is an inverse relationship between the depth of the probe in the dermis and the amount of drug sampled following topical penetration ex vivo. The result is of relevance to the in vivo situation, and it can...

Microneedle-Mediated Delivery of Copper Peptide Through Skin.

Science.gov (United States)

Li, Hairui; Low, Yong Sheng Jason; Chong, Hui Ping; Zin, Melvin T; Lee, Chi-Ying; Li, Bo; Leolukman, Melvina; Kang, Lifeng

2015-08-01

Copper peptide (GHK-Cu) plays an important role in skin regeneration and wound healing. However, its skin absorption remains challenging due to its hydrophilicity. Here we use polymeric microneedle array to pre-treat skin to enhance GHK-Cu skin penetration. Two in vitro skin models were used to assess the capability of microneedles in facilitating skin delivery of GHK-Cu. Histological assay and confocal laser scanning microscopy were performed to characterize and quantify the microconduits created by the microneedles inside skin. Cellular and porcine models were used to evaluate the safety of microneedle-assisted copper peptide delivery. The depth and percentage of microneedle penetration were correlated with application forces, which in turn influenced the extent of enhancement in the skin permeability of GHK-Cu. In 9 h, 134 ± 12 nanomoles of peptide and 705 ± 84 nanomoles of copper permeated though the microneedle treated human skin, while almost no peptide or copper permeated through intact human skin. No obvious signs of skin irritation were observed with the use of GHK-Cu after microneedle pretreatment. It is effective and safe to enhance the skin permeation of GHK-Cu by using microneedles. This approach may be useful to deliver similar peptides or minerals through skin.

Dose characteristics of total-skin electron-beam irradiation with six-dual electron fields

International Nuclear Information System (INIS)

Choi, Tae Jin; Kim, Jin Hee; Kim, Ok Bae

1998-01-01

To obtain the uniform dose at limited depth to entire surface of the body, the dose characteristics of degraded electron beam of the large target-skin distance and the dose distribution of the six-dual electron fields were investigated. The experimental dose distributions included the depth dose curve, spatial dose and attenuated electron beam were determined with 300 cm of Target-Skin Distance (TSD) and full collimator size (35x35 cm 2 on TSD 100 cm) in 4 MeV electron beam energy. Actual collimated field size of 105 cmx105 cm at the distance of 300 cm could include entire hemibody. A patient was standing on step board with hands up and holding the pole to stabilize his/her positions for the six-dual fields technique. As a scatter-degrader, 0.5 cm of acrylic plate was inserted at 20 cm from the body surface on the electron beam path to induce ray scattering and to increase the skin dose. The Full Width at Half Maximum(FWHM) of dose profile was 130 cm in large field of 105x105 cm 2 . The width of 100±10% of the resultant dose from two adjacent fields which were separated at 25 cm from field edge for obtaining the dose uniformity was extended to 186 cm. The depth of maximum dose lies at 5 mm and the 80% depth dose lies between 7 and 8 mm for the degraded electron beam by using the 0.5 cm thickness of acrylic absorber. Total skin electron beam irradiation (TSEBI) was carried out using the six dual fields has been developed at Stanford University. The dose distribution in TSEBI showed relatively uniform around the flat region of skin except the protruding and deeply curvatured portion of the body, which showed excess of dose at the former and less dose at the latter. The percent depth dose, profile curves and superimposed dose distribution were investigated using the degraded using the degraded electron beam through the beam absorber. The dose distribution obtained by experiments of TSEBI showed within±10% difference excepts the protruding area of skin which needs a

Unscheduled DNA synthesis after β-irradiation of mouse skin in situ

International Nuclear Information System (INIS)

Ootsuyama, Akira; Tanooka, Hiroshi

1986-01-01

The skin of ICR mouse was irradiated with β-rays from 90 Sr- 90 Y with surface doses up to 30 krad. Unscheduled DNA synthesis (UDS) was measured by autoradiography after labeling the skin with radioactive thymidine using the forceps-clamping method. The level of UDS in epithelial cells of the skin was detected as an increasing function of radiation dose. Fibroblastic cells, compared with epithelial cells and hair follicle cells at the same depth of the skin, showed a lower level of UDS, indicating a lower DNA repair activity in fibroblasts. Cancer risk of the skin was discussed. (Auth.)

Skin cancers in elderly patients.

Science.gov (United States)

Malaguarnera, Giulia; Giordano, Maria; Cappellani, Alessandro; Berretta, Massimiliano; Malaguarnera, Michele; Perrotta, Rosario Emanuele

2013-11-01

Cancer in older people is a common problem worldwide. Among various types of cancer, skin cancers represent an important percentage. The principal risk factors are sun exposure, family history of skin cancer, fair skin color, but also the age plays an important role in the genesis of skin cancers. In older people there are a more prolonged exposure to carcinogenesis and a decreased functionality of reparation mechanisms of the cells so they acquire a selective advantage of growing and proliferating. At the same time age causes alteration in immune system by increasing NK-cells absolute number and decreasing both the endogenous and the lymphokine-induced lytic activities. The anti-tumor immune response is also mediated by the cytotoxic T- lymphocytes and in the elderly a strong reduction of T-cell function has been demonstrated. In elderly patients the diagnosis and the treatment of skin cancers can be different from younger counterpart. For example in older patients with melanoma is important to evaluate Breslow depth while higher mitotic rate has major value in younger patients. Moreover, the treatment should consider the performance status of patients and their compliance.

Evaluation of dermal-epidermal skin equivalents ('composite-skin') of human keratinocytes in a collagen-glycosaminoglycan matrix(Integra artificial skin).

Science.gov (United States)

Kremer, M; Lang, E; Berger, A C

2000-09-01

Integra artificial skin (Integra LifeSciences Corp., Plainsboro, NJ, USA) is a dermal template consisting of bovine collagen, chondroitin-6-sulphate and a silastic membrane manufactured as Integra. This product has gained widespread use in the clinical treatment of third degree burn wounds and full thickness skin defects of different aetiologies. The product was designed to significantly reduce the time needed to achieve final wound closure in the treatment of major burn wounds, to optimise the sparse autologous donor skin resources and to improve the durable mechanical quality of the skin substitute. The clinical procedure requires two stages. The first step creates a self neodermis, the second creates a self epidermis on the neodermis. However, it is desirable to cover major burn wounds early in a single step by a skin substitute consisting of a dermal equivalent seeded in vitro with autologous keratinocytes ('composite-skin') out of which a full thickness skin develops in vivo.The goal of this experimental study was to develop a method to integrate human keratinocytes in homogeneous distribution and depth into Integra Artificial Skin. The seeded cell-matrix composites were grafted onto athymic mice in order to evaluate their potential to reconstitute a human epidermis in vivo. We were able to demonstrate that the inoculated human keratinocytes reproducibly displayed a homogeneous pattern of distribution, adherence, proliferation and confluence. The cell-matrix composites grafted in this model exhibited good wound adherence, complete healing, minor wound contraction and had the potential to reconstitute an elastic, functional and durable human skin. Histologically we were able to show that the inoculated human keratinocytes in vivo colonised the matrix in a histomorphologically characteristic epidermal pattern (keratomorula, keratinocyte bubbling) and developed a persisting, stratified, keratinising epidermis which immunohistologically proved to be of human

Fathers' experiences with the skin-to-skin method in NICU

DEFF Research Database (Denmark)

Helth, Theresa Dall; Jarden, Mary

2013-01-01

-depth, semi-structured interviews with five fathers of premature infants in the NICU, Copenhagen University Hospital, Hvidovre Hospital, Denmark. Findings: Three themes emerged: 1) “The competent parenthood”. 2) The paternal role and the division of roles between the parents. 3) Balance between working life......Abstract Aim: To explore how fathers of premature infants experience and potentially benefit from using the skin-to-skin (STS) method during their infants’ admission to the neonatal intensive care unit (NICU). Methods, participants and setting: Hermeneutic phenomenological qualitative study. In...... and time spent with the infant. Conclusion: STS enhances the fathers’ ability to play a caring role in their infant’s life. Fathers consider themselves less important, as compared to the mother in relation to their infant. STS enhances an understanding of their own role as a father. Health professionals...

Stressed skin panels

Energy Technology Data Exchange (ETDEWEB)

Anon

2001-07-01

Advantages and disadvantages of stressed skin panels, also known as structural insulated panels (SIPs), are discussed as material and labour-saving alternatives to traditional stick framing. Stressed skin panels are manufactured 'sandwich' assemblies with a rigid insulating polystyrene foam core, whose interior and exterior surfaces are bonded into panels. The skins distribute and carry the structural loading while the bonded foam core provides insulation and keeps the two skins aligned. Since there are fewer framing members, there is little thermal bridging and the R-value remains high. SIPs are usually manufactured in four feet by eight feet panels, although some manufacturers can produce panels up to eight feet by forty feet. SIPs are resource efficient as they use less wood than conventional framing (about 25 per cent less); can structurally cover large spans, requiring less supplementary framing. Use of SIPs eliminate the need for headers over small openings; provide the ability to nail anywhere; create less scrap and waste; lessen vulnerability to unfavourable weather and other job-site hazards, can reduce delays, and often can produce significant savings in material and labour costs. Limitations include the more complex approaches to plumbing and electrical systems, although this can be minimized by designers by incorporating much of the plumbing and electrical work on interior (non-panel) walls. Most stressed skin panels require one-half inch interior gypsum drywall. If become wet, stressed skin panels take a long time to dry out and may harbour mold growth. Larger stressed-skin panels used in floors and roofs, may require cranes or other machinery for handling because of their weight. Although not without some environmental impact, overall, stressed skin panels are judged to be a resource-efficient building technology with significant energy-efficiency benefits and distinct advantages over stick framing. 3 photos.

Skin fluorescence model based on the Monte Carlo technique

Science.gov (United States)

Churmakov, Dmitry Y.; Meglinski, Igor V.; Piletsky, Sergey A.; Greenhalgh, Douglas A.

2003-10-01

The novel Monte Carlo technique of simulation of spatial fluorescence distribution within the human skin is presented. The computational model of skin takes into account spatial distribution of fluorophores following the collagen fibers packing, whereas in epidermis and stratum corneum the distribution of fluorophores assumed to be homogeneous. The results of simulation suggest that distribution of auto-fluorescence is significantly suppressed in the NIR spectral region, while fluorescence of sensor layer embedded in epidermis is localized at the adjusted depth. The model is also able to simulate the skin fluorescence spectra.

Chemical peeling in ethnic/dark skin.

Science.gov (United States)

Roberts, Wendy E

2004-01-01

Chemical peeling for skin of color arose in ancient Egypt, Mesopotamia, and other ancient cultures in and around Africa. Our current fund of medical knowledge regarding chemical peeling is a result of centuries of experience and research. The list of agents for chemical peeling is extensive. In ethnic skin, our efforts are focused on superficial and medium-depth peeling agents and techniques. Indications for chemical peeling in darker skin include acne vulgaris, postinflammatory hyperpigmentation, melasma, scarring, photodamage, and pseudofolliculitis barbae. Careful selection of patients for chemical peeling should involve not only identification of Fitzpatrick skin type, but also determining ethnicity. Different ethnicities may respond unpredictably to chemical peeling regardless of skin phenotype. Familiarity with the properties each peeling agent used is critical. New techniques discussed for chemical peeling include spot peeling for postinflammatory hyperpigmentation and combination peels for acne and photodamage. Single- or combination-agent chemical peels are shown to be efficacious and safe. In conclusion, chemical peeling is a treatment of choice for numerous pigmentary and scarring disorders arising in dark skin tones. Familiarity with new peeling agents and techniques will lead to successful outcomes.

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

Science.gov (United States)

Harth, Yoram; Lischinsky, Daniel

2011-03-01

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

Thermal Analysis of the Fastrac Chamber/Nozzle

Science.gov (United States)

Davis, Darrell

2001-01-01

This paper will describe the thermal analysis techniques used to predict temperatures in the film-cooled ablative rocket nozzle used on the Fastrac 60K rocket engine. A model was developed that predicts char and pyrolysis depths, liner thermal gradients, and temperatures of the bondline between the overwrap and liner. Correlation of the model was accomplished by thermal analog tests performed at Southern Research, and specially instrumented hot fire tests at the Marshall Space Flight Center. Infrared thermography was instrumental in defining nozzle hot wall surface temperatures. In-depth and outboard thermocouple data was used to correlate the kinetic decomposition routine used to predict char and pyrolysis depths. These depths were anchored with measured char and pyrolysis depths from cross-sectioned hot-fire nozzles. For the X-34 flight analysis, the model includes the ablative Thermal Protection System (TPS) material that protects the overwrap from the recirculating plume. Results from model correlation, hot-fire testing, and flight predictions will be discussed.

Thermal Imaging of Skin Changes on the Feet of Type II Diabetics

National Research Council Canada - National Science Library

Ammer, K

2001-01-01

.... Increased temperature of the feet of diabetics is another frequent finding. We investigated the relationship between skin changes and areas of increased skin temperature recorded with an Infrared Scanner ACEMA 870...

A prospective observational study of skin to subarachnoid space depth in the Indian population

Directory of Open Access Journals (Sweden)

Smita Prakash

2014-01-01

Full Text Available Background and Aims: A pre-puncture estimate of skin to subarachnoid space depth (SSD may guide spinal needle placement and reduce complications associated with lumbar puncture. Our aim was to determine (1 The SSD in Indian males, females, parturients and the overall population; (2 To derive formulae for predicting SSD and (3 To determine which previously suggested formula best suited our population. Methods: In this prospective, observational study, 800 adult Indian patients undergoing surgery under spinal anaesthesia were divided into three groups: Males (Group M, females (Group F and parturients (Group PF. SSD was measured after lumbar puncture. The relationship between SSD and patient characteristics was studied and statistical models were used to derive formula for predicting SSD. Statistical analysis included One-way ANOVA with post hoc analysis, forward stepwise multivariate regression analysis and paired t-tests. Results: Mean SSD was 4.71 ± 0.70 cm in the overall population. SSD in adult males (4.81 ± 0.68 cm was significantly longer than that observed in females (4.55 ± 0.66 cm but was comparable with SSD in parturients (4.73 ± 0.73 cm. Formula for predicting SSD in the overall population was 2.71 + 0.09 × Body Mass Index (BMI. Stocker′s formula when applied correlated best with the observed SSD. Formulae were derived for the three groups. Conclusions: We found gender-based differences in SSD, with SSD in males being significantly greater than that observed in the female population. SSD correlated with BMI in the parturient and the overall population. Amongst the previously proposed formulae, Stocker′s formula was most accurate in predicting SSD in our population.

Small cryotherapy devices for the treatment of skin warts.

Science.gov (United States)

Zouboulis, Viktor A; Zouboulis, Christos C

2017-12-01

Effectiveness of cryotherapy on skin wart models. Two small cryotherapy devices, Wartner and Wortie, were administered for 10″-60″ on tomatoes and potatoes used as skin wart models. Frozen surface and depth were evaluated by standardized photography and computer analysis. Tissue temperature at depths of 0.1-10 mm was assessed by an electronic thermometer during treatment. Cryotherapy induced a transient freezing of the tomato surface. The devices produced similar tomato tissue temperature reduction at all depths examined. At 5 mm, Wortie induced lower tissue temperatures than Wartner. Both devices induced potato tissue destruction to a depth of 0.5-1.2 mm at 40″ and 50″. Wartner induced a maximum destruction at 40″, Wortie led to a partially linear destruction depth with freezing time. The devices produced similar reduction of potato tissue temperature at all depths tested. Wartner induced more rapidly lower temperatures (1.5 mm, 10″, p = .001). Wortie induced lower tissue temperatures with time (0.1 mm, 50″, p = .025; 60″, p = .039; 5 mm, 60″, p = .05). None of the devices reached the lethal temperature of -22 °C. Both cryotherapy devices produced sufficient tissue damage, at least in the potatoes, to a depth of 0.5-1.2 mm when applied for 40″ (commercially proposed time).

High resolution SAW elastography for ex-vivo porcine skin specimen

Science.gov (United States)

Zhou, Kanheng; Feng, Kairui; Wang, Mingkai; Jamera, Tanatswa; Li, Chunhui; Huang, Zhihong

2018-02-01

Surface acoustic wave (SAW) elastography has been proven to be a non-invasive, non-destructive method for accurately characterizing tissue elastic properties. Current SAW elastography technique tracks generated surface acoustic wave impulse point by point which are a few millimeters away. Thus, reconstructed elastography has low lateral resolution. To improve the lateral resolution of current SAW elastography, a new method was proposed in this research. A M-B scan mode, high spatial resolution phase sensitive optical coherence tomography (PhS-OCT) system was employed to track the ultrasonically induced SAW impulse. Ex-vivo porcine skin specimen was tested using this proposed method. A 2D fast Fourier transform based algorithm was applied to process the acquired data for estimating the surface acoustic wave dispersion curve and its corresponding penetration depth. Then, the ex-vivo porcine skin elastogram was established by relating the surface acoustic wave dispersion curve and its corresponding penetration depth. The result from the proposed method shows higher lateral resolution than that from current SAW elastography technique, and the approximated skin elastogram could also distinguish the different layers in the skin specimen, i.e. epidermis, dermis and fat layer. This proposed SAW elastography technique may have a large potential to be widely applied in clinical use for skin disease diagnosis and treatment monitoring.

Numerical simulation of time fractional dual-phase-lag model of heat transfer within skin tissue during thermal therapy.

Science.gov (United States)

Kumar, Dinesh; Rai, K N

2017-07-01

In this paper, we investigated the thermal behavior in living biological tissues using time fractional dual-phase-lag bioheat transfer (DPLBHT) model subjected to Dirichelt boundary condition in presence of metabolic and electromagnetic heat sources during thermal therapy. We solved this bioheat transfer model using finite element Legendre wavelet Galerkin method (FELWGM) with help of block pulse function in sense of Caputo fractional order derivative. We compared the obtained results from FELWGM and exact method in a specific case, and found a high accuracy. Results are interpreted in the form of standard and anomalous cases for taking different order of time fractional DPLBHT model. The time to achieve hyperthermia position is discussed in both cases as standard and time fractional order derivative. The success of thermal therapy in the treatment of metastatic cancerous cell depends on time fractional order derivative to precise prediction and control of temperature. The effect of variability of parameters such as time fractional derivative, lagging times, blood perfusion coefficient, metabolic heat source and transmitted power on dimensionless temperature distribution in skin tissue is discussed in detail. The physiological parameters has been estimated, corresponding to the value of fractional order derivative for hyperthermia treatment therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermal injury secondary to laparoscopic fiber-optic cables.

Science.gov (United States)

Hindle, A Katharine; Brody, Fred; Hopkins, Vernon; Rosales, Greg; Gonzalez, Florencia; Schwartz, Arnold

2009-08-01

Laparoscopy requires a reliable light source to provide adequate visualization. However, thermal energy is produced as a by-product from the optical cable. This study attempts to quantify the degree of possible thermal damage secondary to the fiber-optic light source. Using a digital thermometer, temperature measurements were recorded at the tip of optical cables from five different light sources (Karl Storz, Inc., Tuttlingen, Germany). Temperature measurements were recorded with new and old bulbs. The tip of the cable was applied to surgical drapes and the time to charring was recorded. Subsequently, the tip of the optical cable was applied to a porcine model and tissue samples were obtained after varying amounts of time (5, 15, 30, 60, and 90 s). Sections of the damaged tissue were prepared for microscopic evaluation. Parameters for thermal injury included extent of epidermal, dermal, and subcutaneous fat damage and necrosis. The lateral extent and depth of injury were measured. The maximum temperature at the tip of the optical cable varied between 119.5 degrees C and 268.6 degrees C. When surgical drapes were exposed to the tip of the light source, the time to char was 3-6 s. The degree and volume of injury increased with longer exposure times, and significant injury was recorded with the optical cable 3 mm from the skin. This study demonstrates that the temperature at the tip of the optical light cord can induce extensive damage. The by-product of light, heat, can produce immediate superficial tissue necrosis that can extend into the subcutaneous fat even when the optical tip is not in direct contact with the skin. In addition, our study shows the variation in temperature that exists between light sources and bulb status. Overall, surgeons must realize and respect the potential complications associated with optical technology.

Problems associated with localised skin exposures

International Nuclear Information System (INIS)

Wells, J.

1986-01-01

The possible sources of localised skin exposure include small commercial sources (for radiotherapy, for example), radiopharmaceuticals, collimated microbeams, and both fission and activation products from nuclear reactors, neutron generators and associated facilities. Each of these sources has its own particular characteristics and associated problems. Recommendations and regulations relating to limits on skin dose for such exposures have been constrained by inadequate radiobiological data and the limitations inherent in personal dosimetric techniques. A growing body of data is now available for beta-emitters which allows a preliminary reassessment of some aspects of the currently recommended dose limits for localised skin exposures. How the skin dose is measured is particularly important for such exposures, as doses often have to be averaged over a specific area. The area chosen for dose measurement and the depth at which the measurement is made are crucial to understanding the possible biological consequences and for formulating appropriate protection criteria. (author)

In vivo assessment of the structure of skin microcirculation by reflectance confocal-laser-scanning microscopy

Science.gov (United States)

Sugata, Keiichi; Osanai, Osamu; Kawada, Hiromitsu

2012-02-01

One of the major roles of the skin microcirculation is to supply oxygen and nutrition to the surrounding tissue. Regardless of the close relationship between the microcirculation and the surrounding tissue, there are few non-invasive methods that can evaluate both the microcirculation and its surrounding tissue at the same site. We visualized microcapillary plexus structures in human skin using in vivo reflectance confocal-laser-scanning microscopy (CLSM), Vivascope 3000® (Lucid Inc., USA) and Image J software (National Institutes of Health, USA) for video image processing. CLSM is a non-invasive technique that can visualize the internal structure of the skin at the cellular level. In addition to internal morphological information such as the extracellular matrix, our method reveals capillary structures up to the depth of the subpapillary plexus at the same site without the need for additional optical systems. Video images at specific depths of the inner forearm skin were recorded. By creating frame-to-frame difference images from the video images using off-line video image processing, we obtained images that emphasize the brightness depending on changes of intensity coming from the movement of blood cells. Merging images from different depths of the skin elucidates the 3-dimensional fine line-structure of the microcirculation. Overall our results show the feasibility of a non-invasive, high-resolution imaging technique to characterize the skin microcirculation and the surrounding tissue.

Translocation of Cell Penetrating Peptide Engrafted Nanoparticles Across Skin Layers

Science.gov (United States)

Patlolla, Ram R; Desai, Pinaki; Belay, Kalayu; Singh, Mandip

2010-01-01

The objective of the current study was to evaluate the ability of cell penetrating peptides (CPP) to translocate the lipid payload into the skin layers. Fluorescent dye (DID-oil) encapsulated nano lipid crystal nanoparticles (FNLCN) were prepared using Compritol, Miglyol and DOGS-NTA-Ni lipids by hot melt homogenization technique. The FNLCN surface was coated with TAT peptide (FNLCNT) or control YKA peptide (FNLCNY) and in vitro rat skin permeation studies were performed using Franz diffusion cells. Observation of lateral skin sections obtained using cryotome with a confocal microscope demonstrated that skin permeation of FNLCNT was time dependent and after 24 h, fluorescence was observed upto a depth of 120 µm which was localized in the hair follicles and epidermis. In case of FNLCN and FNLCNY formulations fluorescence was mainly observed in the hair follicles. This observation was further supported by confocal Raman spectroscopy where higher fluorescence signal intensity was observed at 80 and 120 µm depth with FNLCNT treated skin and intensity of fluorescence peaks was in the ratio of 2:1:1 and 5:3:1 for FNLCNT, FNLCN, and FNLCNY treated skin sections, respectively. Furthermore, replacement of DID-oil with celecoxib (Cxb), a model lipophilic drug showed similar results and after 24 h, the CXBNT formulation increased the Cxb concentration in SC by 3 and 6 fold and in epidermis by 2 and 3 fold as compared to CXBN and CXBNY formulations respectively. Our results strongly suggest that CPP can translocate nanoparticles with their payloads into deeper skin layers. PMID:20413152

Adjacent field separations for homogenous dose distribution at particular depth and associated hot and cold spots

International Nuclear Information System (INIS)

Supe, S.S.; Deka, A.C.; Deka, B.C.; Sathiyanaranyanan, V.K.

1991-01-01

In radiotherapy treatment planning we come across many situations when treatment is given by using two adjacent fields, for e.g. for treatment of Hodgkin's disease. A pair of adjacent field have been used regularly for the treatment of ovarian tumours. A small separation is given at the skin level, otherwise hot spots are observed at the depth of interest. The separation depend upon tumour depths, and source to skin distance (SSD). Formulae have been derived for the separation as well as for hot and cold spots. The case of adjacent field becomes more complicated when anterior as well as posterior adjacent fields are used. It is not completely possible to avoid the hot and cold spots in such cases. This is partially avoided by shifting the gap on the skin surface during the course of treatment. (author). 2 refs., 2 tabs

Understanding of CO{sub 2} interaction with thermally grown SiO{sub 2} on Si using IBA depth profiling techniques

Energy Technology Data Exchange (ETDEWEB)

Deokar, Geetanjali; D’Angelo, Marie; Briand, Emrick [INSP, UPMC, CNRS UMR 7588, 4 Place Jussieu, Paris F-75005 (France); Deville Cavellin, Catherine, E-mail: deville@univ-paris12.fr [INSP, UPMC, CNRS UMR 7588, 4 Place Jussieu, Paris F-75005 (France); Faculté des Sciences et Technologie UPEC, 61 Av., De Gaulle, Créteil F-94010 (France)

2013-06-01

Interactions between CO{sub 2} and SiO{sub 2} films thermally grown on Si have been studied using {sup 18}O and {sup 13}C as isotopic tracers associated with ion beam analysis (IBA) depth profiling techniques. From secondary ion mass spectrometry (SIMS) measurements no carbon from CO{sub 2} is detected in the silica while it is found in Si. These results suggest that CO{sub 2} diffuses through the silica. Exchanges of oxygen between CO{sub 2} and silica can be observed from {sup 18}O to {sup 16}O SIMS signals variation. The oxygen concentration depth profiles were determined quantitatively using the narrow resonance near 151 keV in the {sup 18}O(p,α){sup 15}N nuclear reaction (Narrow Resonance Profiling, NRP). We demonstrate that two distinct oxygen exchanges processes co-exist and we determine the diffusion coefficient of the CO{sub 2} molecule in the silica at 1100 °C.

Experimental study on occupant's thermal responses under the non-uniform conditions in vehicle cabin during the heating period

Science.gov (United States)

Zhang, Wencan; Chen, Jiqing; Lan, Fengchong

2014-03-01

The existing investigations on thermal comfort mostly focus on the thermal environment conditions, especially of the air-flow field and the temperature distributions in vehicle cabin. Less attention appears to direct to the thermal comfort or thermal sensation of occupants, even to the relationship between thermal conditions and thermal sensation. In this paper, a series of experiments were designed and conducted for understanding the non-uniform conditions and the occupant's thermal responses in vehicle cabin during the heating period. To accurately assess the transient temperature distribution in cabin in common daily condition, the air temperature at a number of positions is measured in a full size vehicle cabin under natural winter environment in South China by using a discrete thermocouples network. The occupant body is divided into nine segments, the skin temperature at each segment and the occupant's local thermal sensation at the head, body, upper limb and lower limb are monitored continuously. The skin temperature is observed by using a discrete thermocouples network, and the local thermal sensation is evaluated by using a seven-point thermal comfort survey questionnaire proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc(ASHRAE) Standard. The relationship between the skin temperature and the thermal sensation is discussed and regressed by statistics method. The results show that the interior air temperature is highly non-uniform over the vehicle cabin. The locations where the occupants sit have a significant effect on the occupant's thermal responses, including the skin temperature and the thermal sensation. The skin temperature and thermal sensation are quite different between body segments due to the effect of non-uniform conditions, clothing resistance, and the human thermal regulating system. A quantitative relationship between the thermal sensation and the skin temperature at each body segment of occupant in

Comparison of Alexandrite and Diode Lasers for Hair Removal in Dark and Medium Skin: Which is Better?

Science.gov (United States)

Mustafa, Farhad Hamad; Jaafar, Mohamad Suhimi; Ismail, Asaad Hamid; Mutter, Kussay Nugamesh

2014-01-01

To improve laser hair removal (LHR) for dark skin, the fluence rate reaching the hair follicle in LHR is important. This paper presents the results of a comparative study examining the function of wavelength on dark skin types using 755 nm alexandrite and 810 nm diode lasers. The structure of the skin was created using a realistic skin model by the Advanced Systems Analysis Program. In this study, the alexandrite laser (755 nm) and diode laser (810 nm) beam-skin tissue interactions were simulated. The simulation results for both lasers differed. The transmission ratio of the diode laser to the dark skin dermis was approximately 4% more than that of the alexandrite laser for the same skin type. For the diode laser at skin depth z = 0.67 mm, the average transmission ratios of both samples were 36% and 27.5%, but those for the alexandrite laser at the same skin depth were 32% and 25%. Both lasers were suitable in LHR for dark skin types, but the diode laser was better than the alexandrite laser because the former could penetrate deeper into the dermis layer.

Comparison of rat epidermal keratinocyte organotypic culture (ROC) with intact human skin

DEFF Research Database (Denmark)

Pappinen, Sari; Hermansson, Martin; Kuntsche, Judith

2008-01-01

study was to compare the stratum corneum lipid content of ROC with the corresponding material from human skin. The lipid composition was determined by thin-layer chromatography (TLC) and mass-spectrometry, and the thermal phase transitions of stratum corneum were studied by differential scanning...... calorimetry (DSC). All major lipid classes of the stratum corneum were present in ROC in a similar ratio as found in human stratum corneum. Compared to human skin, the level of non-hydroxyacid-sphingosine ceramide (NS) was increased in ROC, while alpha-hydroxyacid-phytosphingosine ceramide (AP) and non...... compared to human skin, in agreement with the results from DSC. ROC underwent a lipid lamellar order to disorder transition (T2) at a slightly lower temperature (68 degrees C) than human skin (74 degrees C). These differences in stratum corneum lipid composition and the thermal phase transitions may...

Skin Rejuvenation with Non-Invasive Pulsed Electric Fields

Science.gov (United States)

Golberg, Alexander; Khan, Saiqa; Belov, Vasily; Quinn, Kyle P.; Albadawi, Hassan; Felix Broelsch, G.; Watkins, Michael T.; Georgakoudi, Irene; Papisov, Mikhail; Mihm, Martin C., Jr.; Austen, William G., Jr.; Yarmush, Martin L.

2015-05-01

Degenerative skin diseases affect one third of individuals over the age of sixty. Current therapies use various physical and chemical methods to rejuvenate skin; but since the therapies affect many tissue components including cells and extracellular matrix, they may also induce significant side effects, such as scarring. Here we report on a new, non-invasive, non-thermal technique to rejuvenate skin with pulsed electric fields. The fields destroy cells while simultaneously completely preserving the extracellular matrix architecture and releasing multiple growth factors locally that induce new cells and tissue growth. We have identified the specific pulsed electric field parameters in rats that lead to prominent proliferation of the epidermis, formation of microvasculature, and secretion of new collagen at treated areas without scarring. Our results suggest that pulsed electric fields can improve skin function and thus can potentially serve as a novel non-invasive skin therapy for multiple degenerative skin diseases.

In-depth investigation on physicochemical and thermal properties of magnesium (II gluconate using spectroscopic and thermoanalytical techniques

Directory of Open Access Journals (Sweden)

Mahendra Kumar Trivedi

2017-10-01

Full Text Available Magnesium gluconate is a classical organometallic pharmaceutical compound used for the prevention and treatment of hypomagnesemia as a source of magnesium ion. The present research described the in-depth study on solid state properties viz. physicochemical and thermal properties of magnesium gluconate using sophisticated analytical techniques like PXRD, PSA, FT-IR, UV–Vis spectroscopy, TGA/DTG, and DSC. Magnesium gluconate was found to be crystalline in nature along with the crystallite size ranging from 14.10 to 47.35 nm. The particle size distribution was at d(0.1=6.552 µm, d(0.5=38.299 µm, d(0.9=173.712 µm and D(4,3=67.122 µm along with the specific surface area of 0.372 m2/g. The wavelength for the maximum absorbance was at 198.0 nm. Magnesium gluconate exhibited 88.51% weight loss with three stages of thermal degradation process up to 895.18 °C from room temperature. The TGA/DTG thermograms of the analyte indicated that magnesium gluconate was thermally stable up to around 165 °C. Consequently, the melting temperature of magnesium gluconate was found to be 169.90 °C along with the enthalpy of fusion of 308.7 J/g. Thus, the authors conclude that the achieved results from this study are very useful in pharmaceutical and nutraceutical industries for the identification, characterization and qualitative analysis of magnesium gluconate for preformulation studies and also for developing magnesium gluconate based novel formulation.

Assessment of the Use of Venetian Blinds as Solar Thermal Collectors in Double Skin Facades in Mediterranean Climates

Directory of Open Access Journals (Sweden)

Abel Velasco

2017-11-01

Full Text Available The global trend on energy integration and building efficiency is making both researchers and building developers look for technical solutions to use facade surfaces for energy harvesting. In this work, the assessment of the thermal performance of a double-skin facade (DSF with a venetian blind-type of structure used as a solar thermal collector by means of computational fluid dynamics (CFD is presented. A Venetian blind collector would allow for heat rejection/energy harvesting and exterior views simultaneously and can be easily integrated into the DSF aesthetical design. For the purposes of this study, the modeled facades (south, west, and east-oriented were set to be located in Barcelona (Spain, where large solar gains are a constant condition throughout the year, and such large semi-transparent envelopes lead to interior over-heating in buildings, even during the winter. For the studied facades, both the reductions in radiative heat gains entering the building and the heat recovery in the Venetian blind collector were evaluated for a yearlong operation.

Effects of thermal underwear on thermal and subjective responses in winter.

Science.gov (United States)

Choi, Jeong-Wha; Lee, Joo-Young; Kim, So-Young

2003-01-01

This study was conducted to obtain basic data in improving the health of Koreans, saving energy and protecting environments. This study investigated the effects of wearing thermal underwear for keeping warm in the office in winter where temperature is not as low as affecting work efficiency, on thermoregulatory responses and subjective sensations. In order to create an environment where every subject feels the same thermal sensation, two experimental conditions were selected through preliminary experiments: wearing thermal underwear in 18 degrees C air (18-condition) and not wearing thermal underwear in 23 degrees C air (23-condition). Six healthy male students participated in this study as experiment subjects. Measurement items included rectal temperature (T(re)), skin temperature (T(sk)), clothing microclimate temperature (T(cm)), thermal sensation and thermal comfort. The results are as follows: (1) T(re) of all subjects was maintained constant at 37.1 degrees C under both conditions, indicating no significant differences. (2) (T)(sk) under the 18-condition and the 23-condition were 32.9 degrees C and 33.7 degrees C, respectively, indicating a significant level of difference (pcomfortable under both conditions. It was found (T)(sk) decreased due to a drop in the skin temperature of hands and feet, and the subjects felt cooler wearing only one layer of normal thermal underwear at 18 degrees C. Yet, the thermal comfort level, T(re) and T(cm) of chest part under the 18-condition were the same as those under the 23-condition. These results show that the same level of comfort, T(re) and T(cm) can be maintained as that of an environment about 5 degrees C higher in the office in winter, by wearing one layer of thermal underwear. In this regard, this study suggests that lowering indoor temperature by wearing thermal underwear in winter can contribute to saving energy and improving health.

Thermal Analysis of the MC-1 Chamber/Nozzle

Science.gov (United States)

Davis, Darrell W.; Phelps, Lisa H. (Technical Monitor)

2001-01-01

This paper will describe the thermal analysis techniques used to predict temperatures in the film-cooled ablative rocket nozzle used on the MC-1 60K rocket engine. A model was developed that predicts char and pyrolysis depths, liner thermal gradients, and temperatures of the bondline between the overwrap and liner. Correlation of the model was accomplished by thermal analog tests performed at Southern Research, and specially instrumented hot fire tests at the Marshall Space Flight Center. Infrared thermography was instrumental in defining nozzle hot wall surface temperatures. In-depth and outboard thermocouple data was used to correlate the kinetic decomposition routine used to predict char and pyrolysis depths. These depths were anchored with measured char and pyrolysis depths from cross-sectioned hot-fire nozzles. For the X-34 flight analysis, the model includes the ablative Thermal Protection System (TPS) material that protects the overwrap from the recirculating plume. Results from model correlation, hot-fire testing, and flight predictions will be discussed.

Estimating the time and temperature relationship for causation of deep-partial thickness skin burns.

Science.gov (United States)

Abraham, John P; Plourde, Brian; Vallez, Lauren; Stark, John; Diller, Kenneth R

2015-12-01

The objective of this study is to develop and present a simple procedure for evaluating the temperature and exposure-time conditions that lead to causation of a deep-partial thickness burn and the effect that the immediate post-burn thermal environment can have on the process. A computational model has been designed and applied to predict the time required for skin burns to reach a deep-partial thickness level of injury. The model includes multiple tissue layers including the epidermis, dermis, hypodermis, and subcutaneous tissue. Simulated exposure temperatures ranged from 62.8 to 87.8°C (145-190°F). Two scenarios were investigated. The first and worst case scenario was a direct exposure to water (characterized by a large convection coefficient) with the clothing left on the skin following the exposure. A second case consisted of a scald insult followed immediately by the skin being washed with cool water (20°C). For both cases, an Arrhenius injury model was applied whereby the extent and depth of injury were calculated and compared for the different post-burn treatments. In addition, injury values were compared with experiment data from the literature to assess verification of the numerical methodology. It was found that the clinical observations of injury extent agreed with the calculated values. Furthermore, inundation with cool water decreased skin temperatures more quickly than the clothing insulating case and led to a modest decrease in the burn extent. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Geothermal properties of Swiss Molasse Basin (depth range 0-500 m) - 2006 upgrade of the thermal conductivity, heat capacity, rock density and porosity data base

International Nuclear Information System (INIS)

Leu, W.; Megel, T.; Schaerli, U.

2006-01-01

The main aim of this project is the preparation of a specific data base of geothermal properties for typical rocks of the Swiss Molasse Basin (depth interval 0-500 m). The project includes the development of a new laboratory tool for efficient heat capacity measurements on rock samples, numerous new measurements of geothermal rock properties in the laboratory and calculation of such data from geophysical borehole logs. In the geographical area under review, 282 rock samples, mainly from deep boreholes, were analyzed with the successfully calibrated new heat capacity device and conventional thermal conductivity measuring techniques (cuttings and cores). Based on sonic and density log data from exploration wells, 374 additional data points were generated. This new data base characterizes in detail the six main lithological rock types in the three Molasse groups OSM, OMM and USM within the Swiss Plateau Molasse. The statistical evaluation of all data illustrates the regional variation of the petrophysical and geothermal parameters. For most data groups bulk rock density and thermal conductivity increase, whereas heat capacity decreases in the direction towards the Alpine front. Thermal conductivity shows a distinct increase with depth. Based on this new information and with the aid of the evaluation software tool SwEWS, the costs of planned geothermal installations can be optimized thanks to more precise heat extraction simulations with existing software packages like COSOND, TRNSYS, EWS or WPcalc. (author)

Ablative skin resurfacing.

Science.gov (United States)

Agrawal, Nidhi; Smith, Greg; Heffelfinger, Ryan

2014-02-01

Ablative laser resurfacing has evolved as a safe and effective treatment for skin rejuvenation. Although traditional lasers were associated with significant thermal damage and lengthy recovery, advances in laser technology have improved safety profiles and reduced social downtime. CO2 lasers remain the gold standard of treatment, and fractional ablative devices capable of achieving remarkable clinical improvement with fewer side effects and shorter recovery times have made it a more practical option for patients. Although ablative resurfacing has become safer, careful patient selection and choice of suitable laser parameters are essential to minimize complications and optimize outcomes. This article describes the current modalities used in ablative laser skin resurfacing and examines their efficacy, indications, and possible side effects. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Plasma skin regeneration technology.

Science.gov (United States)

Bogle, M A

2006-09-01

Plasma skin regeneration (PSR) technology uses energy delivered from plasma rather than light or radiofrequency. Plasma is the fourth state of matter in which electrons are stripped from atoms to form an ionized gas. The plasma is emitted in a millisecond pulse to deliver energy to target tissue upon contact without reliance on skin chromophores. The technology can be used at varying energies for different depths of effect, from superficial epidermal sloughing to deeper dermal heating. With the Portrait PSR device (Rhytec, Inc.) there are three treatment guidelines termed PSR1, PSR2, and PSR3. The PSR1 protocol uses a series of low-energy treatments (1.0,1.2 Joules) spaced 3 weeks apart. The PSR2 protocol uses one high-energy pass (3.0, 4.0 Joules) performed in a single treatment, and the PSR3 protocol uses two high-energy passes (3.0 4.0 Joules) performed in a single treatment. All protocols improve fine lines, textural irregularities, and dyspigmentation; however, skin tightening is probably more pronounced with the high-energy treatments.

THERMAL TOMOGRAPHY OF ASTEROID SURFACE STRUCTURE

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Harris, Alan W.; Drube, Line, E-mail: alan.harris@dlr.de [German Aerospace Center (DLR) Institute of Planetary Research, Rutherfordstrasse 2, D-12489 Berlin (Germany)

2016-12-01

Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

Case depth in SAE 1020 steel using barkhausen noise

Directory of Open Access Journals (Sweden)

Alessandra Drehmer

2013-01-01

Full Text Available The most widely used thermochemical process for surface hardening of steels is case hardening. Using several different heat treatments, martensitic surface layers were formed on SAE 1020 steel into which carbon had been diffused. Case depths were measured by traditional destructive techniques. Barkhausen noise measurements were made and both the RMS Barkhausen pulse envelope and the fast Fourier transform (FFT were obtained from numerical calculation. The FFT amplitudes, functions of frequency, were associated with distance from the sample surface using the skin depth equation δ = 1/ (πfσµ½ , where f is the frequency of the electromagnetic wave, s is the electrical conductivity, and µ is the magnetic permeability. We define a normalized power index (NPI which can be used to estimate case depths. The NPI is discussed in relation to the sample microstructure and it is shown that the case depth is most easily determined when the magnetic properties of the surface layer and core are substantially different.

Chimney Effect Assessment of the Double-skin Facade

Institute of Scientific and Technical Information of China (English)

QIU Zhong-zhu; LI Peng; CHOW Tin-tai; REN Jian-xing; WANG Wen-huan

2009-01-01

The mathematic model of heat transfer through ventihted double glazing was verified with themeasured data,which were from a test chamber equipped with glass face temperature,solar radiation,ambient temperature,and wind speed measurement facility.Mter the model validation,the double-skin facade assess-ment was carried out through simulation with ESP-r software integrating thermal simulation and air low net work module.The air flow situation in the air gap was analyzed on the basis of the hourly air velocity simulation data within typical winter week,summer week,spring week and autumn week.The differences of chimney ef-fect in different seasons were discussed,and the thermal loads resulted from the ventilated and unventihted dou-ble skin facade were presented.

Ultrasound-mediated transdermal drug delivery of fluorescent nanoparticles and hyaluronic acid into porcine skin in vitro

International Nuclear Information System (INIS)

Wang Huan-Lei; Fan Peng-Fei; Guo Xia-Sheng; Tu Juan; Zhang Dong; Ma Yong

2016-01-01

Transdermal drug delivery (TDD) can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, amplitude, and exposure time. The delivery of yellow–green fluorescent nanoparticles and high molecular weight hyaluronic acid (HA) in the skin samples was observed by laser confocal microscopy and ultraviolet spectrometry, respectively. The results showed that, with the application of ultrasound exposures, the permeability of the skin to these markers (e.g., their penetration depth and concentration) could be raised above its passive diffusion permeability. Moreover, ultrasound-facilitated TDD was also tested with/without the presence of ultrasound contrast agents (UCAs). When the ultrasound was applied without UCAs, low ultrasound frequency will give a better drug delivery effect than high frequency, but the penetration depth was less likely to exceed 200 μm. However, with the help of the ultrasound-induced microbubble cavitation effect, both the penetration depth and concentration in the skin were significantly enhanced even more. The best ultrasound-facilitated TDD could be achieved with a drug penetration depth of over 600 μm, and the penetration concentrations of fluorescent nanoparticles and HA increased up to about 4–5 folds. In order to get better understanding of ultrasound-facilitated TDD, scanning electron microscopy was used to examine the surface morphology of skin samples, which showed that the skin structure changed greatly under the treatment of ultrasound and UCA. The present work suggests that, for TDD applications (e.g., nanoparticle drug carriers, transdermal patches and cosmetics), protocols and methods presented in this paper are potentially useful. (special topic)

Penetration of ASM 981 in canine skin: a comparative study.

Science.gov (United States)

Gutzwiller, Meret E Ricklin; Reist, Martin; Persohn, Elke; Peel, John E; Roosje, Petra J

2006-01-01

ASM 981 has been developed for topical treatment of inflammatory skin diseases. It specifically inhibits the production and release of pro-inflammatory cytokines. We measured the skin penetration of ASM 981 in canine skin and compared penetration in living and frozen skin. To make penetration of ASM 981 visible in dog skin, tritium labelled ASM 981 was applied to a living dog and to defrosted skin of the same dog. Using qualitative autoradiography the radioactive molecules were detected in the lumen of the hair follicles until the infundibulum, around the superficial parts of the hair follicles and into a depth of the dermis of 200 to 500 microm. Activity could not be found in deeper parts of the hair follicles, the dermis or in the sebaceous glands. Penetration of ASM 981 is low in canine skin and is only equally spread in the upper third of the dermis 24 hours after application. Penetration in frozen skin takes even longer than in living canine skin but shows the same distribution.

A global reference model of Curie-point depths based on EMAG2

Science.gov (United States)

Li, Chun-Feng; Lu, Yu; Wang, Jian

2017-03-01

In this paper, we use a robust inversion algorithm, which we have tested in many regional studies, to obtain the first global model of Curie-point depth (GCDM) from magnetic anomaly inversion based on fractal magnetization. Statistically, the oceanic Curie depth mean is smaller than the continental one, but continental Curie depths are almost bimodal, showing shallow Curie points in some old cratons. Oceanic Curie depths show modifications by hydrothermal circulations in young oceanic lithosphere and thermal perturbations in old oceanic lithosphere. Oceanic Curie depths also show strong dependence on the spreading rate along active spreading centers. Curie depths and heat flow are correlated, following optimal theoretical curves of average thermal conductivities K = ~2.0 W(m°C)-1 for the ocean and K = ~2.5 W(m°C)-1 for the continent. The calculated heat flow from Curie depths and large-interval gridding of measured heat flow all indicate that the global heat flow average is about 70.0 mW/m2, leading to a global heat loss ranging from ~34.6 to 36.6 TW.

The response of human thermal sensation and its prediction to temperature step-change (cool-neutral-cool.

Directory of Open Access Journals (Sweden)

Xiuyuan Du

Full Text Available This paper reports on studies of the effect of temperature step-change (between a cool and a neutral environment on human thermal sensation and skin temperature. Experiments with three temperature conditions were carried out in a climate chamber during the period in winter. Twelve subjects participated in the experiments simulating moving inside and outside of rooms or cabins with air conditioning. Skin temperatures and thermal sensation were recorded. Results showed overshoot and asymmetry of TSV due to the step-change. Skin temperature changed immediately when subjects entered a new environment. When moving into a neutral environment from cool, dynamic thermal sensation was in the thermal comfort zone and overshoot was not obvious. Air-conditioning in a transitional area should be considered to limit temperature difference to not more than 5°C to decrease the unacceptability of temperature step-change. The linear relationship between thermal sensation and skin temperature or gradient of skin temperature does not apply in a step-change environment. There is a significant linear correlation between TSV and Qloss in the transient environment. Heat loss from the human skin surface can be used to predict dynamic thermal sensation instead of the heat transfer of the whole human body.

The Response of Human Thermal Sensation and Its Prediction to Temperature Step-Change (Cool-Neutral-Cool)

Science.gov (United States)

Du, Xiuyuan; Li, Baizhan; Liu, Hong; Yang, Dong; Yu, Wei; Liao, Jianke; Huang, Zhichao; Xia, Kechao

2014-01-01

This paper reports on studies of the effect of temperature step-change (between a cool and a neutral environment) on human thermal sensation and skin temperature. Experiments with three temperature conditions were carried out in a climate chamber during the period in winter. Twelve subjects participated in the experiments simulating moving inside and outside of rooms or cabins with air conditioning. Skin temperatures and thermal sensation were recorded. Results showed overshoot and asymmetry of TSV due to the step-change. Skin temperature changed immediately when subjects entered a new environment. When moving into a neutral environment from cool, dynamic thermal sensation was in the thermal comfort zone and overshoot was not obvious. Air-conditioning in a transitional area should be considered to limit temperature difference to not more than 5°C to decrease the unacceptability of temperature step-change. The linear relationship between thermal sensation and skin temperature or gradient of skin temperature does not apply in a step-change environment. There is a significant linear correlation between TSV and Qloss in the transient environment. Heat loss from the human skin surface can be used to predict dynamic thermal sensation instead of the heat transfer of the whole human body. PMID:25136808

Retrieval of Saharan desert dust optical depth from thermal infrared measurements by IASI

Science.gov (United States)

Vandenbussche, S.; Kochenova, S.; Vandaele, A.-C.; Kumps, N.; De Mazière, M.

2012-04-01

Aerosols are a major actor in the climate system. They are responsible for climate forcing by both direct (by emission, absorption and scattering) and indirect effects (for example, by altering cloud microphysics). A better knowledge of aerosol optical properties, of the atmospheric aerosol load and of aerosol sources and sinks may therefore significantly improve the modeling of climate changes. Aerosol optical depth and other properties are retrieved on an operational basis from daytime measurements in the visible and near infrared spectral range by a number of instruments, like the satellite instruments MODIS, CALIOP, POLDER, MISR and ground-based sunphotometers. Aerosol retrievals from day and night measurements at thermal infrared (TIR) wavelengths (for example, from SEVIRI, AIRS and IASI satellite instruments) are less common, but they receive growing interest in more recent years. Among those TIR measuring instruments, IASI on METOP has one major advantage for aerosol retrievals: its large continuous spectral coverage, allowing to better capture the broadband signature of aerosols. Furthermore, IASI has a high spectral resolution (0.5cm-1 after apodization) which allows retrieving a large number of trace gases at the same time, it will nominally be in orbit for 15 years and offers a quasi global Earth coverage twice a day. Here we will show recently obtained results of desert aerosol properties (concentration, altitude, optical depth) retrieved from IASI TIR measurements, using the ASIMUT software (BIRA-IASB, Belgium) linked to (V)LIDORT (R. Spurr, RTsolutions Inc, US) and to SPHER (M. Mishchenko, NASA GISS, USA). In particular, we will address the case of Saharan desert dust storms, which are a major source of desert dust particles in the atmosphere. Those storms frequently transport sand to Europe, Western Asia or even South America. We will show some test-case comparisons between our retrievals and measurements from other instruments like those listed

Skin Rejuvenation with Non-Invasive Pulsed Electric Fields

Science.gov (United States)

Golberg, Alexander; Khan, Saiqa; Belov, Vasily; Quinn, Kyle P.; Albadawi, Hassan; Felix Broelsch, G.; Watkins, Michael T.; Georgakoudi, Irene; Papisov, Mikhail; Mihm Jr., Martin C.; Austen Jr., William G.; Yarmush, Martin L.

2015-01-01

Degenerative skin diseases affect one third of individuals over the age of sixty. Current therapies use various physical and chemical methods to rejuvenate skin; but since the therapies affect many tissue components including cells and extracellular matrix, they may also induce significant side effects, such as scarring. Here we report on a new, non-invasive, non-thermal technique to rejuvenate skin with pulsed electric fields. The fields destroy cells while simultaneously completely preserving the extracellular matrix architecture and releasing multiple growth factors locally that induce new cells and tissue growth. We have identified the specific pulsed electric field parameters in rats that lead to prominent proliferation of the epidermis, formation of microvasculature, and secretion of new collagen at treated areas without scarring. Our results suggest that pulsed electric fields can improve skin function and thus can potentially serve as a novel non-invasive skin therapy for multiple degenerative skin diseases. PMID:25965851

Thermal detection thresholds of Aδ- and C-fibre afferents activated by brief CO2 laser pulses applied onto the human hairy skin.

Directory of Open Access Journals (Sweden)

Maxim Churyukanov

Full Text Available Brief high-power laser pulses applied onto the hairy skin of the distal end of a limb generate a double sensation related to the activation of Aδ- and C-fibres, referred to as first and second pain. However, neurophysiological and behavioural responses related to the activation of C-fibres can be studied reliably only if the concomitant activation of Aδ-fibres is avoided. Here, using a novel CO(2 laser stimulator able to deliver constant-temperature heat pulses through a feedback regulation of laser power by an online measurement of skin temperature at target site, combined with an adaptive staircase algorithm using reaction-time to distinguish between responses triggered by Aδ- and C-fibre input, we show that it is possible to estimate robustly and independently the thermal detection thresholds of Aδ-fibres (46.9±1.7°C and C-fibres (39.8±1.7°C. Furthermore, we show that both thresholds are dependent on the skin temperature preceding and/or surrounding the test stimulus, indicating that the Aδ- and C-fibre afferents triggering the behavioural responses to brief laser pulses behave, at least partially, as detectors of a change in skin temperature rather than as pure level detectors. Most importantly, our results show that the difference in threshold between Aδ- and C-fibre afferents activated by brief laser pulses can be exploited to activate C-fibres selectively and reliably, provided that the rise in skin temperature generated by the laser stimulator is well-controlled. Our approach could constitute a tool to explore, in humans, the physiological and pathophysiological mechanisms involved in processing C- and Aδ-fibre input, respectively.

Protective Skins for Aerogel Monoliths

Science.gov (United States)

Leventis, Nicholas; Johnston, James C.; Kuczmarski, Maria A.; Meador, Ann B.

2007-01-01

A method of imparting relatively hard protective outer skins to aerogel monoliths has been developed. Even more than aerogel beads, aerogel monoliths are attractive as thermal-insulation materials, but the commercial utilization of aerogel monoliths in thermal-insulation panels has been inhibited by their fragility and the consequent difficulty of handling them. Therefore, there is a need to afford sufficient protection to aerogel monoliths to facilitate handling, without compromising the attractive bulk properties (low density, high porosity, low thermal conductivity, high surface area, and low permittivity) of aerogel materials. The present method was devised to satisfy this need. The essence of the present method is to coat an aerogel monolith with an outer polymeric skin, by painting or spraying. Apparently, the reason spraying and painting were not attempted until now is that it is well known in the aerogel industry that aerogels collapse in contact with liquids. In the present method, one prevents such collapse through the proper choice of coating liquid and process conditions: In particular, one uses a viscous polymer precursor liquid and (a) carefully controls the amount of liquid applied and/or (b) causes the liquid to become cured to the desired hard polymeric layer rapidly enough that there is not sufficient time for the liquid to percolate into the aerogel bulk. The method has been demonstrated by use of isocyanates, which, upon exposure to atmospheric moisture, become cured to polyurethane/polyurea-type coats. The method has also been demonstrated by use of commercial epoxy resins. The method could also be implemented by use of a variety of other resins, including polyimide precursors (for forming high-temperature-resistant protective skins) or perfluorinated monomers (for forming coats that impart hydrophobicity and some increase in strength).

The abdominal skin of female Sprague-Dawley rats is more sensitive than the back skin to drug-induced phototoxicity.

Science.gov (United States)

Kuga, Kazuhiro; Yasuno, Hironobu; Sakai, Yumi; Harada, Yumiko; Shimizu, Fumi; Miyamoto, Yumiko; Takamatsu, Yuki; Miyamoto, Makoto; Sato, Keiichiro

2017-11-01

In vivo phototoxicity studies are important to predict drug-induced phototoxicity in humans; however, a standard methodology has not established. To determine differences in sensitivity to drug-induced phototoxicity among various skin sites, we evaluated phototoxic reactions in the back and abdominal skin of female Sprague-Dawley rats orally dosed with phototoxic drugs (pirfenidone, 8-methoxysoraren, doxycycline, and lomefloxacin) or a non-phototoxic drug (gatifloxacin) followed by solar-simulated light irradiation comprising 18J/cm 2 ultraviolet A. Tissue reactions were evaluated by macroscopic and microscopic examination and immunohistochemistry for γ-H2AX, and tissue concentrations of pirfenidone, doxycycline, and lomefloxacin were measured by tandem mass spectrometry. In addition, the thicknesses of the skin layers at both sites were measured in drug-naïve rats. The abdominal skin showed more severe reactions to all phototoxic drugs than the back skin, whereas the minimal erythema dose in drug-naïve rats and skin concentrations of each drug were comparable between the sites. Furthermore, histopathological lesions and γ-H2AX-positive cells in the abdominal skin were detected in deeper layers than in the back skin. The stratum corneum and dermis in the abdominal skin were significantly thinner than in the back skin, indicating a difference in the depth of light penetration and potentially contributing to the site differences observed in sensitivity to phototoxicity. Gatifloxacin did not induce any phototoxic reactions at either site. In conclusion, the abdominal skin is more sensitive to drug-induced phototoxicity than the back skin and may represent a preferable site for irradiation in this rat phototoxicity model. Copyright © 2017 Elsevier Inc. All rights reserved.

Raman spectroscopy: in vivo quick response code of skin physiological status

Science.gov (United States)

Vyumvuhore, Raoul; Tfayli, Ali; Piot, Olivier; Le Guillou, Maud; Guichard, Nathalie; Manfait, Michel; Baillet-Guffroy, Arlette

2014-11-01

Dermatologists need to combine different clinically relevant characteristics for a better understanding of skin health. These characteristics are usually measured by different techniques, and some of them are highly time consuming. Therefore, a predicting model based on Raman spectroscopy and partial least square (PLS) regression was developed as a rapid multiparametric method. The Raman spectra collected from the five uppermost micrometers of 11 healthy volunteers were fitted to different skin characteristics measured by independent appropriate methods (transepidermal water loss, hydration, pH, relative amount of ceramides, fatty acids, and cholesterol). For each parameter, the obtained PLS model presented correlation coefficients higher than R2=0.9. This model enables us to obtain all the aforementioned parameters directly from the unique Raman signature. In addition to that, in-depth Raman analyses down to 20 μm showed different balances between partially bound water and unbound water with depth. In parallel, the increase of depth was followed by an unfolding process of the proteins. The combinations of all these information led to a multiparametric investigation, which better characterizes the skin status. Raman signal can thus be used as a quick response code (QR code). This could help dermatologic diagnosis of physiological variations and presents a possible extension to pathological characterization.

An antiaging skin care system containing alpha hydroxy acids and vitamins improves the biomechanical parameters of facial skin

Directory of Open Access Journals (Sweden)

Tran D

2014-12-01

Full Text Available Diana Tran, Joshua P Townley, Tanya M Barnes, Kerryn A Greive Ego Pharmaceuticals, Braeside, Victoria, Australia Background: The demand for antiaging products has dramatically increased in recent years, driven by an aging population seeking to maintain the appearance of youth. This study investigates the effects of an antiaging skin care system containing alpha hydroxy acids (AHAs in conjunction with vitamins B3, C, and E on the biomechanical parameters of facial skin. Methods: Fifty two volunteers followed an antiaging skin care regimen comprising of cleanser, eye cream, day moisturizer, and night moisturizer for 21 days. Wrinkle depth (Ry and skin roughness (Ra were measured by skin surface profilometry of the crow's feet area, and skin elasticity parameters R2 (gross elasticity, R5 (net elasticity, R6 (viscoelastic portion, and R7 (recovery after deformation were determined for facial skin by cutometer, preapplication and after 7, 14, and 21 days. Volunteers also completed a self-assessment questionnaire. Results: Compared to baseline, Ry and Ra significantly improved by 32.5% (P<0.0001 and 42.9% (P<0.0001, respectively, after 21 days of antiaging skin care treatment. These results were observed by the volunteers with 9 out of 10 discerning an improvement in skin texture and smoothness. Compared to baseline, R2 and R5 significantly increased by 15.2% (P<0.0001 and 12.5% (P=0.0449, respectively, while R6 significantly decreased by 17.7% (P<0.0001 after 21 days. R7 increased by 9.7% after 21 days compared to baseline but this was not significant over this time period. Conclusion: An antiaging skin care system containing AHAs and vitamins significantly improves the biomechanical parameters of the skin including wrinkles and skin texture, as well as elasticity without significant adverse effects. Keywords: alpha hydroxy acids, antiaging, nicotinamide, vitamin C, vitamin E, profilometry, cutometer

An antiaging skin care system containing alpha hydroxy acids and vitamins improves the biomechanical parameters of facial skin

Science.gov (United States)

Tran, Diana; Townley, Joshua P; Barnes, Tanya M; Greive, Kerryn A

2015-01-01

Background The demand for antiaging products has dramatically increased in recent years, driven by an aging population seeking to maintain the appearance of youth. This study investigates the effects of an antiaging skin care system containing alpha hydroxy acids (AHAs) in conjunction with vitamins B3, C, and E on the biomechanical parameters of facial skin. Methods Fifty two volunteers followed an antiaging skin care regimen comprising of cleanser, eye cream, day moisturizer, and night moisturizer for 21 days. Wrinkle depth (Ry) and skin roughness (Ra) were measured by skin surface profilometry of the crow’s feet area, and skin elasticity parameters R2 (gross elasticity), R5 (net elasticity), R6 (viscoelastic portion), and R7 (recovery after deformation) were determined for facial skin by cutometer, preapplication and after 7, 14, and 21 days. Volunteers also completed a self-assessment questionnaire. Results Compared to baseline, Ry and Ra significantly improved by 32.5% (P<0.0001) and 42.9% (P<0.0001), respectively, after 21 days of antiaging skin care treatment. These results were observed by the volunteers with 9 out of 10 discerning an improvement in skin texture and smoothness. Compared to baseline, R2 and R5 significantly increased by 15.2% (P<0.0001) and 12.5% (P=0.0449), respectively, while R6 significantly decreased by 17.7% (P<0.0001) after 21 days. R7 increased by 9.7% after 21 days compared to baseline but this was not significant over this time period. Conclusion An antiaging skin care system containing AHAs and vitamins significantly improves the biomechanical parameters of the skin including wrinkles and skin texture, as well as elasticity without significant adverse effects. PMID:25552908

#%In-depth investigation on physicochemical and thermal properties of magnesium (II) gluconate using spectroscopic and thermoanalytical techniques

Institute of Scientific and Technical Information of China (English)

#

2017-01-01

Magnesium gluconate is a classical organometallic pharmaceutical compound used for the prevention and treatment of hypomagnesemia as a source of magnesium ion. The present research described the in-depth study on solid state properties viz. physicochemical and thermal properties of magnesium gluconate using sophisticated analytical techniques like Powder X-ray diffraction (PXRD), particle size analysis ( PSA), Fourier transform infrared (FT-IR) spectrometry, ultraviolet–visible (UV–Vis) spectroscopy, thermogravimetric analysis (TGA)/differential thermogravimetric analysis (DTG), and differential scanning calorimetry (DSC). Magnesium gluconate was found to be crystalline in nature along with the crystallite size ranging from 14.10 to 47.35 nm. The particle size distribution was at d(0.1)=6.552 μm, d(0.5)=38.299 μm, d(0.9)=173.712 μm and D(4,3)=67.122 μm along with the specific surface area of 0.372 m2/g. The wavelength for the maximum absorbance was at 198.0 nm. Magnesium gluconate exhibited 88.51% weight loss with three stages of thermal degradation process up to 895.18 ℃ from room temperature. The TGA/DTG thermograms of the analyte indicated that magnesium gluconate was thermally stable up to around 165 ℃. Consequently, the melting temperature of magnesium gluconate was found to be 169.90 ℃ along with the enthalpy of fusion of 308.7 J/g. Thus, the authors conclude that the achieved results from this study are very useful in pharmaceutical and nutraceutical industries for the identification, characterization and qualitative analysis of magnesium gluconate for preformulation studies and also for developing magnesium gluconate based novel formulation.

Numerical investigation on thermal performance and correlations of double skin facade with buoyancy-driven airflow

Energy Technology Data Exchange (ETDEWEB)

Pappas, Alexandra; Zhai, Zhiqiang [Department of Civil, Environmental and Architectural Engineering, University of Colorado, UCB 428, ECOT 441, Boulder, CO 80309-0428 (United States)

2008-07-01

This paper briefly reviews the primary parameters for a double skin facade (DSF) design. The research presents an integrated and iterative modeling process for analyzing the thermal performance of DSF cavities with buoyancy-driven airflow by using a building energy simulation program (BESP) along with a computational fluid dynamics (CFD) package. A typical DSF cavity model has been established and simulated. The model and the modeling process have been calibrated and validated against the experimental data. The validated model was used to develop correlations that can be implemented in a BESP, allowing users to take advantage of the accuracy gained from CFD simulations without the required computation time. Correlations were developed for airflow rate through cavity, average and peak cavity air temperature, cavity air pressure, and interior convection coefficient. The correlations are valuable for 'back of the envelope' calculation and for examining accuracy of zonal-model-based energy and airflow simulation programs. (author)

Phase change material thermal capacitor clothing

Science.gov (United States)

Buckley, Theresa M. (Inventor)

2005-01-01

An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Fractional Microneedling: A Novel Method for Enhancement of Topical Anesthesia Before Skin Aesthetic Procedures.

Science.gov (United States)

El-Fakahany, Hasan; Medhat, Walid; Abdallah, Fahd; Abdel-Raouf, Hamza; Abdelhakeem, Mohammed

2016-01-01

Skin microneedling or fractional microneedle therapy is a recent approach used for skin rejuvenation or to enhance transdermal delivery of topical medications. The authors evaluated the efficacy of skin microneedling, using an automated device, to enhance the numbing effect of topical anesthesia, used before minimally invasive aesthetic approaches. Fifteen patients, looking for treatment of atrophic acne scars, were subjected to randomized split-face study comparing automated fractional skin microneedling (0.5 mm depth) followed by application of topical anesthetic cream (Lidocaine 2.5% + Prilocaine 2.5%) on one side of face, with topical anesthesia alone on the other side, followed by full face fractional microneedling treatment for postacne scars (2.5 mm depth). The treated sides (fractional needling + topical anesthesia) had significantly lower pain scores when compared with the nontreated sides (topical anesthesia alone). The scores of pain sensation, during the whole procedure, were statistically significantly (p aesthetic procedures can be enhanced with fractional microneedling pretreatment.

Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation

Directory of Open Access Journals (Sweden)

Arendt-Nielsen Lars

2010-11-01

Full Text Available Abstract Background CO2 lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial to deeper skin layers. Methods In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO2 laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were compared to the subjective pain intensity ratings from 16 subjects and to the surface skin temperature distributions measured by an infrared camera. Results The stimulations were sensed significantly slower and less intense in glabrous skin than they were in hairy skin (MANOVA, p 0.90, p 2 (5 W, 0.12 s, d1/e2 = 11.4 mm only two reported pain to glabrous skin stimulation using the same stimulus intensity. The temperature at the epidermal-dermal junction (depth 50 μm in hairy and depth 133 μm in glabrous skin was estimated to 46°C for hairy skin stimulation and 39°C for glabrous skin stimulation. Conclusions As compared to previous one dimensional heat distribution models, the current two dimensional model provides new possibilities for detailed studies regarding CO2 laser stimulation intensity, temperature levels and nociceptor activation.

Using fractal analysis of thermal signatures for thyroid disease evaluation

Science.gov (United States)

Gavriloaia, Gheorghe; Sofron, Emil; Gavriloaia, Mariuca-Roxana; Ghemigean, Adina-Mariana

2010-11-01

The skin is the largest organ of the body and it protects against heat, light, injury and infection. Skin temperature is an important parameter for diagnosing diseases. Thermal analysis is non-invasive, painless, and relatively inexpensive, showing a great potential research. Since the thyroid regulates metabolic rate it is intimately connected to body temperature, more than, any modification of its function generates a specific thermal image on the neck skin. The shapes of thermal signatures are often irregular in size and shape. Euclidean geometry is not able to evaluate their shape for different thyroid diseases, and fractal geometry is used in this paper. Different thyroid diseases generate different shapes, and their complexity are evaluated by specific mathematical approaches, fractal analysis, in order to the evaluate selfsimilarity and lacunarity. Two kinds of thyroid diseases, hyperthyroidism and papillary cancer are analyzed in this paper. The results are encouraging and show the ability to continue research for thermal signature to be used in early diagnosis of thyroid diseases.

Nociceptive sensations evoked from 'spots' in the skin by mild cooling and heating.

Science.gov (United States)

Green, Barry G; Roman, Carolyn; Schoen, Kate; Collins, Hannah

2008-03-01

It was recently found that nociceptive sensations (stinging, pricking, or burning) can be evoked by cooling or heating the skin to innocuous temperatures (e.g., 29 and 37 degrees C). Here, we show that this low-threshold thermal nociception (LTN) can be traced to sensitive 'spots' in the skin equivalent to classically defined warm spots and cold spots. Because earlier work had shown that LTN is inhibited by simply touching a thermode to the skin, a spatial search procedure was devised that minimized tactile stimulation by sliding small thermodes (16 and 1mm(2)) set to 28 or 36 degrees C slowly across the lubricated skin of the forearm. The procedure uncovered three types of temperature-sensitive sites (thermal, bimodal, and nociceptive) that contained one or more thermal, nociceptive, or (rarely) bimodal spots. Repeated testing indicated that bimodal and nociceptive sites were less stable over time than thermal sites, and that mechanical contact differentially inhibited nociceptive sensations. Intensity ratings collected over a range of temperatures showed that LTN increased monotonically on heat-sensitive sites but not on cold-sensitive sites. These results provide psychophysical evidence that stimulation from primary afferent fibers with thresholds in the range of warm fibers and cold fibers is relayed to the pain pathway. However, the labile nature of LTN implies that these low-threshold nociceptive inputs are subject to inhibitory controls. The implications of these findings for the roles of putative temperature receptors and nociceptors in innocuous thermoreception and thermal pain are discussed.

Depth resolved investigations of boron implanted silicon

Science.gov (United States)

Sztucki, M.; Metzger, T. H.; Milita, S.; Berberich, F.; Schell, N.; Rouvière, J. L.; Patel, J.

2003-01-01

We have studied the depth distribution and structure of defects in boron implanted silicon (0 0 1). Silicon wafers were implanted with a boron dose of 6×10 15 ions/cm -2 at 32 keV and went through different annealing treatments. Using diffuse X-ray scattering at grazing incidence and exit angles we are able to distinguish between different kinds of defects (point defect clusters and extrinsic stacking faults on {1 1 1} planes) and to determine their depth distribution as a function of the thermal budget. Cross-section transmission electron microscopy was used to gain complementary information. In addition we have determined the strain distribution caused by the boron implantation as a function of depth from rocking curve measurements.

Modeling laser speckle imaging of perfusion in the skin (Conference Presentation)

Science.gov (United States)

Regan, Caitlin; Hayakawa, Carole K.; Choi, Bernard

2016-02-01

Laser speckle imaging (LSI) enables visualization of relative blood flow and perfusion in the skin. It is frequently applied to monitor treatment of vascular malformations such as port wine stain birthmarks, and measure changes in perfusion due to peripheral vascular disease. We developed a computational Monte Carlo simulation of laser speckle contrast imaging to quantify how tissue optical properties, blood vessel depths and speeds, and tissue perfusion affect speckle contrast values originating from coherent excitation. The simulated tissue geometry consisted of multiple layers to simulate the skin, or incorporated an inclusion such as a vessel or tumor at different depths. Our simulation used a 30x30mm uniform flat light source to optically excite the region of interest in our sample to better mimic wide-field imaging. We used our model to simulate how dynamically scattered photons from a buried blood vessel affect speckle contrast at different lateral distances (0-1mm) away from the vessel, and how these speckle contrast changes vary with depth (0-1mm) and flow speed (0-10mm/s). We applied the model to simulate perfusion in the skin, and observed how different optical properties, such as epidermal melanin concentration (1%-50%) affected speckle contrast. We simulated perfusion during a systolic forearm occlusion and found that contrast decreased by 35% (exposure time = 10ms). Monte Carlo simulations of laser speckle contrast give us a tool to quantify what regions of the skin are probed with laser speckle imaging, and measure how the tissue optical properties and blood flow affect the resulting images.

Development of a test device to characterize thermal protective performance of fabrics against hot steam and thermal radiation

International Nuclear Information System (INIS)

Su, Yun; Li, Jun

2016-01-01

Steam burns severely threaten the life of firefighters in the course of their fire-ground activities. The aim of this paper was to characterize thermal protective performance of flame-retardant fabrics exposed to hot steam and low-level thermal radiation. An improved testing apparatus based on ASTM F2731-11 was developed in order to simulate the routine fire-ground conditions by controlling steam pressure, flow rate and temperature of steam box. The thermal protective performance of single-layer and multi-layer fabric system with/without an air gap was studied based on the calibrated tester. It was indicated that the new testing apparatus effectively evaluated thermal properties of fabric in hot steam and thermal radiation. Hot steam significantly exacerbated the skin burn injuries while the condensed water on the skin’s surface contributed to cool down the skin tissues during the cooling. Also, the absorbed thermal energy during the exposure and the cooling was mainly determined by the fabric’s configuration, the air gap size, the exposure time and the existence of hot steam. The research provides a effective method to characterize the thermal protection of fabric in complex conditions, which will help in optimization of thermal protection performance of clothing and reduction of steam burn. (paper)

Three-dimensional in-situ subsurface density estimations and the seismic skin depth

CSIR Research Space (South Africa)

Fourie, CJS

2008-01-01

Full Text Available All electromagnetic geophysical methods, but the frequency domain methods in particular, depend on the skindepth as a guide to the depth of investigation or penetration from the surface. By definition the skindepth is the distance where the initial...

Imaging photoplethysmography for clinical assessment of cutaneous microcirculation at two different depths

Science.gov (United States)

Marcinkevics, Zbignevs; Rubins, Uldis; Zaharans, Janis; Miscuks, Aleksejs; Urtane, Evelina; Ozolina-Moll, Liga

2016-03-01

The feasibility of bispectral imaging photoplethysmography (iPPG) system for clinical assessment of cutaneous microcirculation at two different depths is proposed. The iPPG system has been developed and evaluated for in vivo conditions during various tests: (1) topical application of vasodilatory liniment on the skin, (2) skin local heating, (3) arterial occlusion, and (4) regional anesthesia. The device has been validated by the measurements of a laser Doppler imager (LDI) as a reference. The hardware comprises four bispectral light sources (530 and 810 nm) for uniform illumination of skin, video camera, and the control unit for triggering of the system. The PPG signals were calculated and the changes of perfusion index (PI) were obtained during the tests. The results showed convincing correlations for PI obtained by iPPG and LDI at (1) topical liniment (r=0.98) and (2) heating (r=0.98) tests. The topical liniment and local heating tests revealed good selectivity of the system for superficial microcirculation monitoring. It is confirmed that the iPPG system could be used for assessment of cutaneous perfusion at two different depths, morphologically and functionally different vascular networks, and thus utilized in clinics as a cost-effective alternative to the LDI.

Analysis of the Tikhonov regularization to retrieve thermal conductivity depth-profiles from infrared thermography data

Science.gov (United States)

Apiñaniz, Estibaliz; Mendioroz, Arantza; Salazar, Agustín; Celorrio, Ricardo

2010-09-01

We analyze the ability of the Tikhonov regularization to retrieve different shapes of in-depth thermal conductivity profiles, usually encountered in hardened materials, from surface temperature data. Exponential, oscillating, and sigmoidal profiles are studied. By performing theoretical experiments with added white noises, the influence of the order of the Tikhonov functional and of the parameters that need to be tuned to carry out the inversion are investigated. The analysis shows that the Tikhonov regularization is very well suited to reconstruct smooth profiles but fails when the conductivity exhibits steep slopes. We check a natural alternative regularization, the total variation functional, which gives much better results for sigmoidal profiles. Accordingly, a strategy to deal with real data is proposed in which we introduce this total variation regularization. This regularization is applied to the inversion of real data corresponding to a case hardened AISI1018 steel plate, giving much better anticorrelation of the retrieved conductivity with microindentation test data than the Tikhonov regularization. The results suggest that this is a promising way to improve the reliability of local inversion methods.

Interpreting Repeated Temperature-Depth Profiles for Groundwater Flow

NARCIS (Netherlands)

Bense, Victor F.; Kurylyk, Barret L.; Daal, van Jonathan; Ploeg, van der Martine J.; Carey, Sean K.

2017-01-01

Temperature can be used to trace groundwater flows due to thermal disturbances of subsurface advection. Prior hydrogeological studies that have used temperature-depth profiles to estimate vertical groundwater fluxes have either ignored the influence of climate change by employing steady-state

Nonablative lightweight thermal protection system for Mars Aeroflyby Sample collection mission

Science.gov (United States)

Suzuki, Toshiyuki; Aoki, Takuya; Ogasawara, Toshio; Fujita, Kazuhisa

2017-07-01

In this study, the concept of a nonablative lightweight thermal protection system (NALT) were proposed for a Mars exploration mission currently under investigation in Japan. The NALT consists of a carbon/carbon (C/C) composite skin, insulator tiles, and a honeycomb sandwich panel. Basic thermal characteristics of the NALT were obtained by conducting heating tests in high-enthalpy facilities. Thermal conductivity values of the insulator tiles as well as the emissivity values of the C/C skin were measured to develop a numerical analysis code for predicting NALT's thermal performance in flight environments. Finally, a breadboard model of a 600-mm diameter NALT aeroshell was developed and qualified through vibration and thermal vacuum tests.

What is the effect of different skin types on the required dose for photodynamic therapy?

CSIR Research Space (South Africa)

Karsten, AE

2008-11-01

Full Text Available For effective laser treatment it is very important to provide the correct dose at the required treatment depth. In South Africa we have a richness of ethnic groups contributing to a large variety in skin tones. Effective laser treatment of skin...

Clinical optical coherence tomography combined with multiphoton tomography for evaluation of several skin disorders

Science.gov (United States)

König, Karsten; Speicher, Marco; Bückle, Rainer; Reckfort, Julia; McKenzie, Gordon; Welzel, Julia; Koehler, Martin J.; Elsner, Peter; Kaatz, Martin

2010-02-01

The first clinical trial of optical coherence tomography (OCT) combined with multiphoton tomography (MPT) and dermoscopy is reported. State-of-the-art (i) OCT systems for dermatology (e.g. multibeam swept source OCT), (ii) the femtosecond laser multiphoton tomograph DermaInspectTM, and (iii) digital dermoscopes were applied to 47 patients with a diversity of skin diseases and disorders such as skin cancer, psoriasis, hemangioma, connective tissue diseases, pigmented lesions, and autoimmune bullous skin diseases. Dermoscopy, also called 'epiluminescent microscopy', provides two-dimensional color images of the skin surface. OCT imaging is based on the detection of optical reflections within the tissue measured interferometrically whereas nonlinear excitation of endogenous fluorophores and the second harmonic generation are the bases of MPT images. OCT cross sectional "wide field" image provides a typical field of view of 5 x 2 mm2 and offers fast information on the depth and the volume of the investigated lesion. In comparison, multiphoton tomography presents 0.36 x 0.36 mm2 horizontal or diagonal sections of the region of interest within seconds with submicron resolution and down to a tissue depth of 200 μm. The combination of OCT and MPT provides a synergistic optical imaging modality for early detection of skin cancer and other skin diseases.

Thermal behavior and ice-table depth within the north polar erg of Mars

Science.gov (United States)

Putzig, Nathaniel E.; Mellon, Michael T.; Herkenhoff, Kenneth E.; Phillips, Roger J.; Davis, Brian J.; Ewer, Kenneth J.; Bowers, Lauren M.

2014-01-01

We fully resolve a long-standing thermal discrepancy concerning the north polar erg of Mars. Several recent studies have shown that the erg’s thermal properties are consistent with normal basaltic sand overlying shallow ground ice or ice-cemented sand. Our findings bolster that conclusion by thoroughly characterizing the thermal behavior of the erg, demonstrating that other likely forms of physical heterogeneity play only a minor role, and obviating the need to invoke exotic materials. Thermal inertia as calculated from orbital temperature observations of the dunes has previously been found to be more consistent with dust-sized materials than with sand. Since theory and laboratory data show that dunes will only form out of sand-sized particles, exotic sand-sized agglomerations of dust have been invoked to explain the low values of thermal inertia. However, the polar dunes exhibit the same darker appearance and color as that of dunes found elsewhere on the planet that have thermal inertia consistent with normal sand-sized basaltic grains, whereas Martian dust deposits are generally lighter and redder. The alternative explanation for the discrepancy as a thermal effect of a shallow ice table is supported by our analysis of observations from the Mars Global Surveyor Thermal Emission Spectrometer and the Mars Odyssey Thermal Emission Imaging System and by forward modeling of physical heterogeneity. In addition, our results exclude a uniform composition of dark dust-sized materials, and they show that the thermal effects of the dune slopes and bright interdune materials evident in high-resolution images cannot account for the erg’s thermal behavior.

Thermal behavior and ice-table depth within the north polar erg of Mars

Science.gov (United States)

Putzig, Nathaniel E.; Mellon, Michael T.; Herkenhoff, Kenneth E.; Phillips, Roger J.; Davis, Brian J.; Ewer, Kenneth J.; Bowers, Lauren M.

2014-02-01

We fully resolve a long-standing thermal discrepancy concerning the north polar erg of Mars. Several recent studies have shown that the erg's thermal properties are consistent with normal basaltic sand overlying shallow ground ice or ice-cemented sand. Our findings bolster that conclusion by thoroughly characterizing the thermal behavior of the erg, demonstrating that other likely forms of physical heterogeneity play only a minor role, and obviating the need to invoke exotic materials. Thermal inertia as calculated from orbital temperature observations of the dunes has previously been found to be more consistent with dust-sized materials than with sand. Since theory and laboratory data show that dunes will only form out of sand-sized particles, exotic sand-sized agglomerations of dust have been invoked to explain the low values of thermal inertia. However, the polar dunes exhibit the same darker appearance and color as that of dunes found elsewhere on the planet that have thermal inertia consistent with normal sand-sized basaltic grains, whereas Martian dust deposits are generally lighter and redder. The alternative explanation for the discrepancy as a thermal effect of a shallow ice table is supported by our analysis of observations from the Mars Global Surveyor Thermal Emission Spectrometer and the Mars Odyssey Thermal Emission Imaging System and by forward modeling of physical heterogeneity. In addition, our results exclude a uniform composition of dark dust-sized materials, and they show that the thermal effects of the dune slopes and bright interdune materials evident in high-resolution images cannot account for the erg's thermal behavior.

In-vitro Investigations of Skin Closure using Diode Laser and Protein Solder Containing Gold Nanoshells

Directory of Open Access Journals (Sweden)

Mohammad Sadegh Nourbakhsh

2010-12-01

Full Text Available Introduction: Laser tissue soldering is a new technique for repair of various tissues including the skin, liver, articular cartilage and nerves and is a promising alternative to suture. To overcome the problems of thermal damage to surrounding tissues and low laser penetration depth, some exogenous chromophores such as gold nanoshells, a new class of nanoparticles consisting of a dielectric core surrounded by a thin metal shell, are used. The aims of this study were to use two different concentrations of gold nanoshells as the exogenous material for skin tissue soldering and also to examine the effects of laser soldering parameters on the properties of the repaired skin. Material and Methods: Two mixtures of albumin solder and different concentrations of gold nanoshells were prepared. A full thickness incision of 2×20 mm2 was made on the surface and after placing 50 μl of the solder mixture on the incision, an 810 nm diode laser was used to irradiate it at different power densities. The changes of tensile strength, σt, due to temperature rise, number of scan (Ns, and scan velocity (Vs were investigated. Results: The results showed that the tensile strength of the repaired skin increased with increasing irradiance for both gold nanoshell concentrations. In addition, at constant laser irradiance (I, the tensile strength of the repaired incision increased with increasing Ns and decreasing Vs. In our case, this corresponded to st = 1610 g/cm2 at I ~ 60 Wcm-2, T ~ 65ºC, Ns = 10 and Vs = 0.2 mms-1. Discussion and Conclusion: Gold nanoshells can be used as an indocyanine green dye (ICG alterative for laser tissue soldering.  Although by increasing the laser power density, the tensile strength of the repaired skin increases, an optimum power density must be considered due to the resulting increase in tissue temperature.

Signal filtering algorithm for depth-selective diffuse optical topography

International Nuclear Information System (INIS)

Fujii, M; Nakayama, K

2009-01-01

A compact filtered backprojection algorithm that suppresses the undesirable effects of skin circulation for near-infrared diffuse optical topography is proposed. Our approach centers around a depth-selective filtering algorithm that uses an inverse problem technique and extracts target signals from observation data contaminated by noise from a shallow region. The filtering algorithm is reduced to a compact matrix and is therefore easily incorporated into a real-time system. To demonstrate the validity of this method, we developed a demonstration prototype for depth-selective diffuse optical topography and performed both computer simulations and phantom experiments. The results show that the proposed method significantly suppresses the noise from the shallow region with a minimal degradation of the target signal.

Anti-inflammatory activity of Punica granatum L. (Pomegranate) rind extracts applied topically to ex vivo skin.

Science.gov (United States)

Houston, David M J; Bugert, Joachim; Denyer, Stephen P; Heard, Charles M

2017-03-01

Coadministered pomegranate rind extract (PRE) and zinc (II) produces a potent virucidal activity against Herpes simplex virus (HSV); however, HSV infections are also associated with localised inflammation and pain. Here, the objective was to determine the anti-inflammatory activity and relative depth penetration of PRE, total pomegranate tannins (TPT) and zinc (II) in skin, ex vivo. PRE, TPT and ZnSO 4 were dosed onto freshly excised ex vivo porcine skin mounted in Franz diffusion cells and analysed for COX-2, as a marker for modulation of the arachidonic acid inflammation pathway, by Western blotting and immunohistochemistry. Tape stripping was carried out to construct relative depth profiles. Topical application of PRE to ex vivo skin downregulated expression of COX-2, which was significant after just 6h, and maintained for up to 24h. This was achieved with intact stratum corneum, proving that punicalagin penetrated skin, further supported by the depth profiling data. When PRE and ZnSO 4 were applied together, statistically equal downregulation of COX-2 was observed when compared to the application of PRE alone; no effect followed the application of ZnSO 4 alone. TPT downregulated COX-2 less than PRE, indicating that tannins alone may not be entirely responsible for the anti-inflammatory activity of PRE. Punicalagin was found throughout the skin, in particular the lower regions, indicating appendageal delivery as a significant route to the viable epidermis. Topical application of TPT and PRE had significant anti-inflammatory effects in ex vivo skin, confirming that PRE penetrates the skin and modulates COX-2 regulation in the viable epidermis. Pomegranates have potential as a novel approach in ameliorating the inflammation and pain associated with a range of skin conditions, including cold sores and herpetic stromal keratitis. Copyright © 2016 Elsevier B.V. All rights reserved.

Skin Diseases: Skin Health and Skin Diseases

Science.gov (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 ...

Thermal characteristics of thermobrachytherapy surface applicators for treating chest wall recurrence

International Nuclear Information System (INIS)

Arunachalam, K; Maccarini, P F; Craciunescu, O I; Stauffer, P R; Schlorff, J L

2010-01-01

The aim of this study was to investigate temperature and thermal dose distributions of thermobrachytherapy surface applicators (TBSAs) developed for concurrent or sequential high dose rate (HDR) brachytherapy and microwave hyperthermia treatment of chest wall recurrence and other superficial diseases. A steady-state thermodynamics model coupled with the fluid dynamics of a water bolus and electromagnetic radiation of the hyperthermia applicator is used to characterize the temperature distributions achievable with TBSAs in an elliptical phantom model of the human torso. Power deposited by 915 MHz conformal microwave array (CMA) applicators is used to assess the specific absorption rate (SAR) distributions of rectangular (500 cm 2 ) and L-shaped (875 cm 2 ) TBSAs. The SAR distribution in tissue and fluid flow distribution inside the dual-input dual-output (DIDO) water bolus are coupled to solve the steady-state temperature and thermal dose distributions of the rectangular TBSA (R-TBSA) for superficial tumor targets extending 10-15 mm beneath the skin surface. Thermal simulations are carried out for a range of bolus inlet temperature (T b = 38-43 deg. C), water flow rate (Q b = 2-4 L min -1 ) and tumor blood perfusion (ω b = 2-5 kg m -3 s -1 ) to characterize their influence on thermal dosimetry. Steady-state SAR patterns of the R- and L-TBSA demonstrate the ability to produce conformal and localized power deposition inside the tumor target sparing surrounding normal tissues and nearby critical organs. Acceptably low variation in tissue surface cooling and surface temperature homogeneity was observed for the new DIDO bolus at a 2 L min -1 water flow rate. Temperature depth profiles and thermal dose volume histograms indicate bolus inlet temperature (T b ) to be the most influential factor on thermal dosimetry. A 42 deg. C water bolus was observed to be the optimal choice for superficial tumors extending 10-15 mm from the surface even under significant blood perfusion

Distribution and depth of bottom-simulating reflectors in the Nankai subduction margin

Science.gov (United States)

Ohde, Akihiro; Otsuka, Hironori; Kioka, Arata; Ashi, Juichiro

2018-04-01

Surface heat flow has been observed to be highly variable in the Nankai subduction margin. This study presents an investigation of local anomalies in surface heat flows on the undulating seafloor in the Nankai subduction margin. We estimate the heat flows from bottom-simulating reflectors (BSRs) marking the lower boundaries of the methane hydrate stability zone and evaluate topographic effects on heat flow via two-dimensional thermal modeling. BSRs have been used to estimate heat flows based on the known stability characteristics of methane hydrates under low-temperature and high-pressure conditions. First, we generate an extensive map of the distribution and subseafloor depths of the BSRs in the Nankai subduction margin. We confirm that BSRs exist at the toe of the accretionary prism and the trough floor of the offshore Tokai region, where BSRs had previously been thought to be absent. Second, we calculate the BSR-derived heat flow and evaluate the associated errors. We conclude that the total uncertainty of the BSR-derived heat flow should be within 25%, considering allowable ranges in the P-wave velocity, which influences the time-to-depth conversion of the BSR position in seismic images, the resultant geothermal gradient, and thermal resistance. Finally, we model a two-dimensional thermal structure by comparing the temperatures at the observed BSR depths with the calculated temperatures at the same depths. The thermal modeling reveals that most local variations in BSR depth over the undulating seafloor can be explained by topographic effects. Those areas that cannot be explained by topographic effects can be mainly attributed to advective fluid flow, regional rapid sedimentation, or erosion. Our spatial distribution of heat flow data provides indispensable basic data for numerical studies of subduction zone modeling to evaluate margin parallel age dependencies of subducting plates.[Figure not available: see fulltext.

Skin, eye, and testis: current exposure problems and recent advances in radiobiology

International Nuclear Information System (INIS)

Charles, M.W.

1986-01-01

Three organs, the skin, eye and testis are potentially at risk from poorly penetrating radiations such as beta particles or low energy X-Rays. They may be preferentially irradiated in fields with steep depth - dose gradients and thereby dictate radiological protection procedures. Since there is not a wide margin of safety in the annual permissible dose limits for these organs it is important to have clearly defensible methods of dose assessment. This requires both an adequate understanding of the radiobiology of these organs and the availability of experimental techniques for measuring doses at various depths near the surface of the body. This paper reviews the current state of knowledge in this field, drawing partly on information from two recent CEC workshops on the 'Dosimetry of Beta Particles and Low Energy X-Rays' and 'Radiation Damage to the Skin'. It is concluded that protection criteria for the limitation of skin dose are in need of revision. (author)

Skin dose variation: influence of energy

International Nuclear Information System (INIS)

Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

2004-01-01

Full text: This research aimed to quantitatively evaluate the differences in percentage dose of maximum for 6MV and 18MV x-ray beams within the first lcm of interactions. Thus provide quantitative information regarding the basal, dermal and subcutaneous dose differences achievable with these two types of high-energy x-ray beams. Percentage dose of maximum build up curves are measured for most clinical field sizes using 6MV and 18MV x-ray beams. Calculations are performed to produce quantitative results highlighting the percentage dose of maximum differences delivered to various depths within the skin and subcutaneous tissue region by these two beams Results have shown that basal cell layer doses are not significantly different for 6MV and 18Mv x-ray beams At depths beyond the surface and basal cell layer there is a measurable and significant difference in delivered dose. This variation increases to 20% of maximum and 22% of maximum at Imm and 1cm depths respectively. The percentage variations are larger for smaller field sizes where the photon in phantom component of the delivered dose is the most significant contributor to dose By producing graphs or tables of % dose differences in the build up region we can provide quantitative information to the oncologist for consideration (if skin and subcutaneous tissue doses are of importance) during the beam energy selection process for treatment. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

Storage Conditions of Skin Affect Tissue Structure and Subsequent in vitro Percutaneous Penetration

DEFF Research Database (Denmark)

Nielsen, Jesper Bo; Plasencia Gil, Maria Inés; Sørensen, Jens Ahm

2011-01-01

fluorescence microscopy) and in vitro percutaneous penetration of caffeine under four different storage conditions using skin samples from the same donors: fresh skin, skin kept at -20°C for 3 weeks (with or without the use of polyethylene glycol) and at -80°C. Our results show a correlation between increasing...... permeation of caffeine and tissue structural damage caused by the storage conditions, most so after skin storage at -80°C. The presented approach, which combines imaging techniques with studies on percutaneous penetration, enables the link between tissue damage at selected depths and penetration...

Temperature and depth error in the mechanical bathythermograph data from the Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Gautham, S.; Pankajakshan, T.

are used to understand the observed errors in temperature and depth of MBT data. The estimated error from the match up data shows that both temperature and depth measurement of MBT are over estimated, compared to CTD measurements. Estimated thermal bias...

Skin optical clearing potential of disaccharides

Science.gov (United States)

Feng, Wei; Shi, Rui; Ma, Ning; Tuchina, Daria K.; Tuchin, Valery V.; Zhu, Dan

2016-08-01

Skin optical clearing can significantly enhance the ability of biomedical optical imaging. Some alcohols and sugars have been selected to be optical clearing agents (OCAs). In this work, we paid attention to the optical clearing potential of disaccharides. Sucrose and maltose were chosen as typical disaccharides to compare with fructose, an excellent monosaccharide-OCA, by using molecular dynamics simulation and an ex vivo experiment. The experimental results indicated that the optical clearing efficacy of skin increases linearly with the concentration for each OCA. Both the theoretical predication and experimental results revealed that the two disaccharides exerted a better optical clearing potential than fructose at the same concentration, and sucrose is optimal. Since maltose has an extremely low saturation concentration, the other two OCAs with saturation concentrations were treated topically on rat skin in vivo, and optical coherence tomography imaging was applied to monitor the optical clearing process. The results demonstrated that sucrose could cause a more significant increase in imaging depth and signal intensity than fructose.

Comparative characteristics of the results of fractional photothermolysis used for neck skin of women in different age groups

Directory of Open Access Journals (Sweden)

L. V. Kirsanova

2014-01-01

Full Text Available The purpose of this research is scientific rationale for fractional photothermolysis usage to correct age-related changes of neck skin of women in different age groups. Materials and Methods. A comparative study of the results for fractional photothermolysis (FP treatment in order to correct involutional changes in neck skin of 60 women in different age groups has been carried out (first group - 40-49 years old, second group - 50-60 years old. Skin moisture, its smoothness (relief, the width of the mouths of the pilosebaceous unit, the severity of pigmentation, the depth and width of wrinkles before the treatment, 1 week after and 1 month after the procedure have been investigated. Main results. After a week of having FP it affected all investigated functional skin parameters more in the 2nd age group than in the 1st one. Decreasing in moisture and smoothness of the skin, increasing the width and the depth of wrinkles, pores and pigmentation width have been marked. In one month there was more significant positive dynamics in parameters of smoothness, wrinkles width in the 2nd group (p -8, p -7 than in the 1st group (p = 0.002, p -5. Hydration of the skin, the width of the mouths of the pilosebaceous unit, the depth of wrinkles and pigmentation changed more significantly among patients in group 1 (p -7, p = 0.001, p -5, p -8. Conclusion. Skin functional parameters of patients from the first group deteriorated significantly less in comparison with the second group one week after PF procedure was carried out. 1 month after the 1st group is indicated with significant improvement in moisture, the width of the pilosebaceous unit, the depth of wrinkles and pigmentation, and the 2nd group is indicated with improvement of smoothness and width of wrinkles. The differences discovered in skin condition dynamics in different age groups should be considered when planning the aesthetic outcome of FP procedure.

Skin Tattoos Alter Sweat Rate and Na+ Concentration.

Science.gov (United States)

Luetkemeier, Maurie Joe; Hanisko, Joseph Michael; Aho, Kyle Mathiew

2017-07-01

The popularity of tattoos has increased tremendously in the last 10 yr particularly among athletes and military personnel. The tattooing process involves permanently depositing ink under the skin at a similar depth as eccrine sweat glands (3-5 mm). The purpose of this study was to compare the sweat rate and sweat Na concentration of tattooed versus nontattooed skin. The participants were 10 healthy men (age = 21 ± 1 yr), all with a unilateral tattoo covering a circular area at least 5.2 cm. Sweat was stimulated by iontophoresis using agar gel disks impregnated with 0.5% pilocarpine nitrate. The nontattooed skin was located contralateral to the position of the tattooed skin. The disks used to collect sweat were composed of Tygon® tubing wound into a spiral so that the sweat was pulled into the tubing by capillary action. The sweat rate was determined by weighing the disk before and after sweat collection. The sweat Na concentration was determined by flame photometry. The mean sweat rate from tattooed skin was significantly less than nontattooed skin (0.18 ± 0.15 vs 0.35 ± 0.25 mg·cm·min; P = 0.001). All 10 participants generated less sweat from tattooed skin than nontattooed skin and the effect size was -0.79. The mean sweat Na concentration from tattooed skin was significantly higher than nontattooed skin (69.1 ± 28.9 vs 42.6 ± 15.2 mmol·L; P = 0.02). Nine of 10 participants had higher sweat Na concentration from tattooed skin than nontattooed skin, and the effect size was 1.01. Tattooed skin generated less sweat and a higher Na concentration than nontattooed skin when stimulated by pilocarpine iontophoresis.

Beginning DotNetNuke Skinning and Design

CERN Document Server

Hay, Andrew

2011-01-01

DotNetNuke is an open source framework built on top of the ASP.Net platform. While this system offers an impressive set of out-of-the-box features for public and private sites, it also includes a compelling story for folks who want to present a unique look and feel to visitors. The skinning engine inside of DotNetNuke has strengthened over the course of several years and hundreds of thousands of registered users. The success of its skin and module developer community is another key indicator of the depth and breadth of this technology. The Core Team responsible for the DotNetNuke brand has gon

[Effect of ionizing radiation and other factors on the thermal sensitivity of mouse skin].

Science.gov (United States)

Kurpeshev, O K; Konopliannikov, A G

1987-03-01

A study was made of the effect of various agents on skin injury by hyperthermia in experiments on noninbred albino mice. The effects of heating were assessed by the frequency of skin necrosis development. The results of the study showed that irradiation of the skin (30 Gy) before heating did not influence its thermosensitivity whereas heating 45-180 days after irradiation proved more effective. Ethanol, metronidazole, thyrocalcitonin and actinomycin D decreased skin thermosensitivity, and cyclohexamide, serotonin, hyperglycemia and applying a tourniquet increased it. The DMF value for actinomycin D depended on the temperature of heating. One should distinguish between true modification of tissue thermosensitivity (determined by cellular factors) and indirect modification (associated with change in volumetric circulation rate).

Biological Rhythms in the Skin

Directory of Open Access Journals (Sweden)

Mary S. Matsui

2016-05-01

Full Text Available Circadian rhythms, ≈24 h oscillations in behavior and physiology, are reflected in all cells of the body and function to optimize cellular functions and meet environmental challenges associated with the solar day. This multi-oscillatory network is entrained by the master pacemaker located in the suprachiasmatic nucleus (SCN of the hypothalamus, which directs an organism’s rhythmic expression of physiological functions and behavior via a hierarchical system. This system has been highly conserved throughout evolution and uses transcriptional–translational autoregulatory loops. This master clock, following environmental cues, regulates an organism’s sleep pattern, body temperature, cardiac activity and blood pressure, hormone secretion, oxygen consumption and metabolic rate. Mammalian peripheral clocks and clock gene expression have recently been discovered and are present in all nucleated cells in our body. Like other essential organ of the body, the skin also has cycles that are informed by this master regulator. In addition, skin cells have peripheral clocks that can function autonomously. First described in 2000 for skin, this review summarizes some important aspects of a rapidly growing body of research in circadian and ultradian (an oscillation that repeats multiple times during a 24 h period cutaneous rhythms, including clock mechanisms, functional manifestations, and stimuli that entrain or disrupt normal cycling. Some specific relationships between disrupted clock signaling and consequences to skin health are discussed in more depth in the other invited articles in this IJMS issue on Sleep, Circadian Rhythm and Skin.

Proof-of-concept: 3D bioprinting of pigmented human skin constructs.

Science.gov (United States)

Ng, Wei Long; Qi, Jovina Tan Zhi; Yeong, Wai Yee; Naing, May Win

2018-01-23

Three-dimensional (3D) pigmented human skin constructs have been fabricated using a 3D bioprinting approach. The 3D pigmented human skin constructs are obtained from using three different types of skin cells (keratinocytes, melanocytes and fibroblasts from three different skin donors) and they exhibit similar constitutive pigmentation (pale pigmentation) as the skin donors. A two-step drop-on-demand bioprinting strategy facilitates the deposition of cell droplets to emulate the epidermal melanin units (pre-defined patterning of keratinocytes and melanocytes at the desired positions) and manipulation of the microenvironment to fabricate 3D biomimetic hierarchical porous structures found in native skin tissue. The 3D bioprinted pigmented skin constructs are compared to the pigmented skin constructs fabricated by conventional a manual-casting approach; in-depth characterization of both the 3D pigmented skin constructs has indicated that the 3D bioprinted skin constructs have a higher degree of resemblance to native skin tissue in term of the presence of well-developed stratified epidermal layers and the presence of a continuous layer of basement membrane proteins as compared to the manually-cast samples. The 3D bioprinting approach facilitates the development of 3D in vitro pigmented human skin constructs for potential toxicology testing and fundamental cell biology research.

Estimation of thermal sensation during varied air temperature conditions.

Science.gov (United States)

Katsuura, T; Tabuchi, R; Iwanaga, K; Harada, H; Kikuchi, Y

1998-03-01

Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.

Histologic analyses on the response of the skin to 1,927-nm fractional thulium fiber laser treatment.

Science.gov (United States)

Kwon, In Ho; Bae, Youin; Yeo, Un-Cheol; Lee, Jin Yong; Kwon, Hyuck Hoon; Choi, Young Hee; Park, Gyeong-Hun

2018-02-01

The histologic responses to varied parameters of 1,927-nm fractional thulium fiber laser treatment have not yet been sufficiently elucidated. This study sought to evaluate histologic changes immediately after 1,927-nm fractional thulium fiber laser session at various parameters. The dorsal skin of Yucatan mini-pig was treated with 1,927-nm fractional thulium fiber laser at varied parameters, with or without skin drying. The immediate histologic changes were evaluated to determine the effects of varying laser parameters on the width and the depth of treated zones. The increase in the level of pulse energy widened the area of epidermal changes in the low power level, but increased the dermal penetration depth in the high power level. As the pulse energy level increased, the increase in the power level under the given pulse energy level more evidently made dermal penetration deeper and the treatment area smaller. Skin drying did not show significant effects on epidermal changes, but evidently increased the depth of dermal denaturation under both high and low levels of pulse energy. These results may provide important information to establish treatment parameters of the 1,927-nm fractional thulium fiber laser for various skin conditions.

Surface applicator calibration and commissioning of an electronic brachytherapy system for nonmelanoma skin cancer treatment

International Nuclear Information System (INIS)

Rong, Yi; Welsh, James S.

2010-01-01

Purpose: The Xoft Axxent x-ray source has been used for treating nonmelanoma skin cancer since the surface applicators became clinically available in 2009. The authors report comprehensive calibration procedures for the electronic brachytherapy (eBx) system with the surface applicators. Methods: The Xoft miniature tube (model S700) generates 50 kVp low-energy x rays. The new surface applicators are available in four sizes of 10, 20, 35, and 50 mm in diameter. The authors' tests include measurements of dose rate, air-gap factor, output stability, depth dose verification, beam flatness and symmetry, and treatment planning with patient specific cutout factors. The TG-61 in-air method was used as a guideline for acquiring nominal dose-rate output at the skin surface. A soft x-ray parallel-plate chamber (PTW T34013) and electrometer was used for the output commissioning. GafChromic EBT films were used for testing the properties of the treatment fields with the skin applicators. Solid water slabs were used to verify the depth dose and cutout factors. Patients with basal cell or squamous cell carcinoma were treated with eBx using a calibrated Xoft system with the low-energy x-ray source and the skin applicators. Results: The average nominal dose-rate output at the skin surface for the 35 mm applicator is 1.35 Gy/min with ±5% variation for 16 sources. The dose-rate output and stability (within ±5% variation) were also measured for the remaining three applicators. For the same source, the output variation is within 2%. The effective source-surface distance was calculated based on the air-gap measurements for four applicator sizes. The field flatness and symmetry are well within 5%. Percentage depth dose in water was provided by factory measurements and can be verified using solid water slabs. Treatment duration was calculated based on the nominal dose rate, the prescription fraction size, the depth dose percentage, and the cutout factor. The output factor needs to be

Surface applicator calibration and commissioning of an electronic brachytherapy system for nonmelanoma skin cancer treatment

Energy Technology Data Exchange (ETDEWEB)

Rong, Yi; Welsh, James S. [Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 and University of Wisconsin Cancer Center-Riverview, Riverview Hospital Association, Wisconsin Rapids, Wisconsin 54494 (United States); Department of Human Oncology and Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792 and University of Wisconsin Cancer Center-Riverview, Riverview Hospital Association, Wisconsin Rapids, Wisconsin 54494 (United States)

2010-10-15

Purpose: The Xoft Axxent x-ray source has been used for treating nonmelanoma skin cancer since the surface applicators became clinically available in 2009. The authors report comprehensive calibration procedures for the electronic brachytherapy (eBx) system with the surface applicators. Methods: The Xoft miniature tube (model S700) generates 50 kVp low-energy x rays. The new surface applicators are available in four sizes of 10, 20, 35, and 50 mm in diameter. The authors' tests include measurements of dose rate, air-gap factor, output stability, depth dose verification, beam flatness and symmetry, and treatment planning with patient specific cutout factors. The TG-61 in-air method was used as a guideline for acquiring nominal dose-rate output at the skin surface. A soft x-ray parallel-plate chamber (PTW T34013) and electrometer was used for the output commissioning. GafChromic EBT films were used for testing the properties of the treatment fields with the skin applicators. Solid water slabs were used to verify the depth dose and cutout factors. Patients with basal cell or squamous cell carcinoma were treated with eBx using a calibrated Xoft system with the low-energy x-ray source and the skin applicators. Results: The average nominal dose-rate output at the skin surface for the 35 mm applicator is 1.35 Gy/min with {+-}5% variation for 16 sources. The dose-rate output and stability (within {+-}5% variation) were also measured for the remaining three applicators. For the same source, the output variation is within 2%. The effective source-surface distance was calculated based on the air-gap measurements for four applicator sizes. The field flatness and symmetry are well within 5%. Percentage depth dose in water was provided by factory measurements and can be verified using solid water slabs. Treatment duration was calculated based on the nominal dose rate, the prescription fraction size, the depth dose percentage, and the cutout factor. The output factor needs

Surface applicator calibration and commissioning of an electronic brachytherapy system for nonmelanoma skin cancer treatment.

Science.gov (United States)

Rong, Yi; Welsh, James S

2010-10-01

The Xoft Axxent x-ray source has been used for treating nonmelanoma skin cancer since the surface applicators became clinically available in 2009. The authors report comprehensive calibration procedures for the electronic brachytherapy (eBx) system with the surface applicators. The Xoft miniature tube (model S700) generates 50 kVp low-energy x rays. The new surface applicators are available in four sizes of 10, 20, 35, and 50 mm in diameter. The authors' tests include measurements of dose rate, air-gap factor, output stability, depth dose verification, beam flatness and symmetry, and treatment planning with patient specific cutout factors. The TG-61 in-air method was used as a guideline for acquiring nominal dose-rate output at the skin surface. A soft x-ray parallel-plate chamber (PTW T34013) and electrometer was used for the output commissioning. GafChromic EBT films were used for testing the properties of the treatment fields with the skin applicators. Solid water slabs were used to verify the depth dose and cutout factors. Patients with basal cell or squamous cell carcinoma were treated with eBx using a calibrated Xoft system with the low-energy x-ray source and the skin applicators. The average nominal dose-rate output at the skin surface for the 35 mm applicator is 1.35 Gy/min with +/- 5% variation for 16 sources. The dose-rate output and stability (within +/- 5% variation) were also measured for the remaining three applicators. For the same source, the output variation is within 2%. The effective source-surface distance was calculated based on the air-gap measurements for four applicator sizes. The field flatness and symmetry are well within 5%. Percentage depth dose in water was provided by factory measurements and can be verified using solid water slabs. Treatment duration was calculated based on the nominal dose rate, the prescription fraction size, the depth dose percentage, and the cutout factor. The output factor needs to be measured for each case with

Skin-effect in a dense ionizing plasma

International Nuclear Information System (INIS)

Ivanenkov, G.V.; Taranenko, S.B.

1989-01-01

Effect of multiple ionization and radiation (bremmstrahlung and photorecombination) on skin effect in a dense plasma is investigated. Limiting cases are considered: 1) fast skin-effect, when plasma movement and any types of losses (radiation, electron thermal conductivity) have no time to manifest themselves during short heating times; 2) deceleration of skinning under effect of radiation achieving equilibrium with Joule heating. Self-simulating solutions of the problem for half-space are investigated. The results are applied to analysing experiments with exploding wires. It is shown that under conditions, typical of heavy-current decelerators tubular structures are produced as a result of heat and current skinning under free dispersion of plasma produced during the explosion. Their dimensions are of the order of dozens of microns, and the temperature exceeds 50 eV. The linear power and complete ''tube'' radiation yield at this stage are able to make a substantial contribution to the energy balance in the group

Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation

Science.gov (United States)

2010-01-01

Background CO2 lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial to deeper skin layers. Methods In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO2 laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were compared to the subjective pain intensity ratings from 16 subjects and to the surface skin temperature distributions measured by an infrared camera. Results The stimulations were sensed significantly slower and less intense in glabrous skin than they were in hairy skin (MANOVA, p 0.90, p < 0.001). Of the 16 subjects tested; eight subjects reported pricking pain in the hairy skin following a stimulus of 0.6 J/cm2 (5 W, 0.12 s, d1/e2 = 11.4 mm) only two reported pain to glabrous skin stimulation using the same stimulus intensity. The temperature at the epidermal-dermal junction (depth 50 μm in hairy and depth 133 μm in glabrous skin) was estimated to 46°C for hairy skin stimulation and 39°C for glabrous skin stimulation. Conclusions As compared to previous one dimensional heat distribution models, the current two dimensional model provides new possibilities for detailed studies regarding CO2 laser stimulation intensity, temperature levels and nociceptor activation. PMID:21059226

Ultraviolet-laser ablation of skin

Energy Technology Data Exchange (ETDEWEB)

Lane, R.J.; Linsker, R.; Wynne, J.J.; Torres, A.; Geronemus, R.G.

1985-05-01

The authors report on the use of pulsed ultraviolet-laser irradiation at 193 nm from an argon-fluoride laser and at 248 nm from a krypton-fluoride laser to ablate skin. In vitro, both wavelengths performed comparably, removing tissue precisely and cleanly, and leaving minimal thermal damage to the surrounding tissue. In vivo, the 193-nm laser radiation failed to remove tissue after bleeding began. The 248-nm radiation, however, continued to remove tissue despite bleeding and left a clean incision with only minimal thermal damage. The krypton-fluoride excimer laser beam at 248 nm, which should be deliverable through a quartz optical fiber, has great potential as a surgical instrument.

Advances in plasma skin regeneration.

Science.gov (United States)

Foster, K Wade; Moy, Ronald L; Fincher, Edgar F

2008-09-01

Plasma skin regeneration (PSR) is a novel method of resurfacing that uses plasma energy to create a thermal effect on the skin. PSR is different from lasers, light sources, and ablative lasers in that it is not chromophore dependent and does not vaporize tissue, but leaves a layer of intact, desiccated epidermis that acts as a natural biologic dressing and promotes wound healing and rapid recovery. Histological studies performed on plasma resurfacing patients have confirmed continued collagen production, reduction of elastosis, and progressive skin rejuvenation beyond 1 year after treatment. PSR has received US Food and Drug Administration 510 (k) clearance for treatment of rhytides of the body, superficial skin lesions, actinic keratoses, viral papillomata, and seborrheic keratoses. PSR also has beneficial effects in the treatment of other conditions including dyschromias, photoaging, skin laxity, and acne scars. The safety profile of PSR is excellent, and there have been no reports of demarcation lines in perioral, periorbital, or jawline areas, as can sometimes be observed following CO2 resurfacing. PSR is effective in improving facial and periorbital rhytides and can be used on nonfacial sites, including the hands, neck, and chest. Numerous treatment protocols with variable energy settings allow for individualized treatments and provide the operator with fine control over the degree of injury and length of subsequent recovery time.

Further search for selectivity of positron annihilation in the skin and cancerous systems

International Nuclear Information System (INIS)

Liu Guang; Chen Hongmin; Chakka, Lakshmi; Cheng Meiling; Gadzia, Joseph E.; Suzuki, R.; Ohdaira, T.; Oshima, N.; Jean, Y.C.

2008-01-01

Positronium annihilation lifetime (PAL) spectroscopy and Doppler broadening energy spectra (DBES) have been used to search for selectivity and sensitivity for cancerous skin samples with and without cancer. This study is to further explore the melanoma cancerous system and other different types of skin samples. We found that the S parameter in melanoma skin samples cut at 0.39 mm depth from the same patient's skin is smaller than near the skin surface. However in 10 melanoma samples from different patients, the S parameters vary significantly. Similarly, among 10 normal skin samples without cancer, the S parameters also vary largely among different patients. To understand the sensitivity of PAS as a tool to detect cancer formation at the early stage, we propose a controlled and systematic study of in vivo experiments using UV-induced cancer skin from living animals

Characterization of Skin Allograft Use in Thermal Injury

Science.gov (United States)

2013-01-01

of burn surgery. New York: Marcel Dekker; 2004. 6. Burd A, Lam PK, Lau H. Allogenic skin: transplant or dressing? Burns 2002;28:358–66. 7...with CPA, and the feet (1.4%) and groin (0.5%) together have CPA placed at ɚ% of all engraftments (Figure 5). When propensity matched for TBSA ( N = 72...nonallografted and allografted patients propensity matched on TBSA Variable No. Nonallograft N Allograft P TBSA 36 34.83 ± 18.74 (0.5–90) 36 35.14

Flexible composite material with phase change thermal storage

Science.gov (United States)

Buckley, Theresa M. (Inventor)

2001-01-01

A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, ,gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Thermal screening of facial skin arterial hot spots using non-contact infrared radiometry

International Nuclear Information System (INIS)

Williams, E M; Heusch, A I; McCarthy, P W

2008-01-01

Non-contact infrared thermometry of facial skin offers advantages over less accessible internal body sites, especially when considering mass screening for febrile infectious disease. The forehead offers an obvious site, but does not present an isothermic surface, as various small arteries passing close to the surface create 'hot-spots'. The aim of this study is to use non-contact infrared (IR) thermometry to determine the link between the temperature at specific facial skin sites and clinical body temperature. A sample of 169 asymptomatic adults (age range 18–54 years) was screened with IR thermometers (Braun Thermoscan proLT for auditory meatus (AM) temperature representing clinical body temperature, and a Raytek, Raynger MX for skin surface temperature). Peak IR skin temperature was measured over the course of each posterior auricular artery (PAA) and each superficial temporal artery (STA). In a sub-group (n = 54) the peak skin temperature of the forehead's metopic region (MR) was also recorded. There were no differences (P > 0.05) between the PAA and STA at 34.2 ± 0.9 °C and 34.2 ± 0.7 °C, respectively, which were 2.5 °C cooler than the AM temperature (36.7 ± 0.5 °C, p 2 = 0.63, p < 0.001) between PAA and STA. There were no asymmetric temperature differences between the left and right sides and males had warmer skin over the MR (F, 33.6 ± 0.7 °C versus M, 34.4 ± 0.6 °C, p < 0.001). Although a lack of correlation between either PAA or STA and AM was apparent in asymptomatics, further research in symptomatics is required to determine the usefulness of these measurements in mass screening of conditions such as fever

Skin Wound Healing: An Update on the Current Knowledge and Concepts.

Science.gov (United States)

Sorg, Heiko; Tilkorn, Daniel J; Hager, Stephan; Hauser, Jörg; Mirastschijski, Ursula

2017-01-01

The integrity of healthy skin plays a crucial role in maintaining physiological homeostasis of the human body. The skin is the largest organ system of the body. As such, it plays pivotal roles in the protection against mechanical forces and infections, fluid imbalance, and thermal dysregulation. At the same time, it allows for flexibility to enable joint function in some areas of the body and more rigid fixation to hinder shifting of the palm or foot sole. Many instances lead to inadequate wound healing which necessitates medical intervention. Chronic conditions such as diabetes mellitus or peripheral vascular disease can lead to impaired wound healing. Acute trauma such as degloving or large-scale thermal injuries are followed by a loss of skin organ function rendering the organism vulnerable to infections, thermal dysregulation, and fluid loss. For this update article, we have reviewed the actual literature on skin wound healing purposes focusing on the main phases of wound healing, i.e., inflammation, proliferation, epithelialization, angiogenesis, remodeling, and scarring. The reader will get briefed on new insights and up-to-date concepts in skin wound healing. The macrophage as a key player in the inflammatory phase will be highlighted. During the epithelialization process, we will present the different concepts of how the wound will get closed, e.g., leapfrogging, lamellipodial crawling, shuffling, and the stem cell niche. The neovascularization represents an essential component in wound healing due to its fundamental impact from the very beginning after skin injury until the end of the wound remodeling. Here, the distinct pattern of the neovascularization process and the special new functions of the pericyte will be underscored. At the end, this update will present 3 topics of high interest in skin wound healing issues, dealing with scarring, tissue engineering, and plasma application. Although wound healing mechanisms and specific cell functions in wound

A global reference model of Moho depths based on WGM2012

Science.gov (United States)

Zhou, D.; Li, C.

2017-12-01

The crust-mantle boundary (Moho discontinuity) represents the largest density contrast in the lithosphere, which can be detected by Bouguer gravity anomaly. We present our recent inversion of global Moho depths from World Gravity Map 2012. Because oceanic lithospheres increase in density as they cool, we perform thermal correction based on the plate cooling model. We adopt a temperature Tm=1300°C at the bottom of lithosphere. The plate thickness is tested by varying by 5 km from 90 to 140 km, and taken as 130 km that gives a best-fit crustal thickness constrained by seismic crustal thickness profiles. We obtain the residual Bouguer gravity anomalies by subtracting the thermal correction from WGM2012, and then estimate Moho depths based on the Parker-Oldenburg algorithm. Taking the global model Crust1.0 as a priori constraint, we adopt Moho density contrasts of 0.43 and 0.4 g/cm3 , and initial mean Moho depths of 37 and 20 km in the continental and oceanic domains, respectively. The number of iterations in the inversion is set to be 150, which is large enough to obtain an error lower than a pre-assigned convergence criterion. The estimated Moho depths range between 0 76 km, and are averaged at 36 and 15 km in continental and oceanic domain, respectively. Our results correlate very well with Crust1.0 with differences mostly within ±5.0 km. Compared to the low resolution of Crust1.0 in oceanic domain, our results have a much larger depth range reflecting diverse structures such as ridges, seamounts, volcanic chains and subduction zones. Base on this model, we find that young(95mm/yr) we observe relatively thicker crust. Conductive cooling of lithosphere may constrain the melting of the mantle at ultraslow spreading centers. Lower mantle temperatures indicated by deeper Curie depths at slow and fast spreading ridges may decrease the volume of magmatism and crustal thickness. This new global model of gravity-derived Moho depth, combined with geochemical and Curie

Integrated fiber optical and thermal sensor for noninvasive monitoring of blood and human tissue

Science.gov (United States)

Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schiffner, Gerhard

2007-05-01

A novel concept of noninvasive monitoring of human tissue and blood based on optical diffuse reflective spectroscopy combined with metabolic heat measurements has been under development. A compact integrated fiber optical and thermal sensor has been developed. The idea of the method was to evaluate by optical spectroscopy haemoglobin and derivative concentrations and supplement with data associated with the oxidative metabolism of glucose. Body heat generated by glucose oxidation is based on the balance of capillary glucose and oxygen supply to the cells. The variation in glucose concentration is followed also by a difference from a distance (or depth) of scattered through the body radiation. So, blood glucose can be estimated by measuring the body heat and the oxygen supply. The sensor pickup contains of halogen lamp and LEDs combined with fiber optical bundle to deliver optical radiation inside and through the patient body, optical and thermal detectors. Fiber optical probe allows diffuse scattering measurement down to a depth of 2.5 mm in the skin including vascular system, which contributes to the control of the body temperature. The sensor pickup measures thermal generation, heat balance, blood flow rate, haemoglobin and derivative concentrations, environmental conditions. Multivariate statistical analysis was applied to convert various signals from the sensor pickup into physicochemical variables. By comparing the values from the noninvasive measurement with the venous plasma result, analytical functions for patient were obtained. Cluster analysis of patient groups was used to simplify a calibration procedure. Clinical testing of developed sensor is being performed.

Skin temperature increase mediated by wearable, long duration, low-intensity therapeutic ultrasound

Science.gov (United States)

Langer, Matthew D.; Huang, Wenyi; Ghanem, Angi; Guo, Yuan; Lewis, George K.

2017-03-01

One of the safety concerns with the delivery of therapeutic ultrasound is overheating of the transducer-skin interface due to poor or improper coupling. The objective of this research was to define a model that could be used to calculate the heating in the skin as a result of a novel, wearable long-duration ultrasound device. This model was used to determine that the maximum heating in the skin remained below the minimum threshold necessary to cause thermal injury over multiple hours of use. In addition to this model data, a human clinical study used wire thermocouples on the skin surface to measure heating characteristics during treatment with the sustained ultrasound system. Parametric analysis of the model determined that the maximum temperature increase is at the surface of the skin ranged from 40-41.8° C when perfusion was taken into account. The clinical data agreed well with the model predictions. The average steady state temperature observed across all 44 subjects was 40°C. The maximum temperature observed was less than 44° C, which is clinically safe for over 5 hours of human skin contact. The resultant clinical temperature data paired well with the model data suggesting the model can be used for future transducer and ultrasound system design simulation. As a result, the device was validated for thermal safety for typical users and use conditions.

Tissue responses to fractional transient heating with sinusoidal heat flux condition on skin surface.

Science.gov (United States)

Ezzat, Magdy A; El-Bary, Alaa A; Al-Sowayan, Noorah S

2016-10-01

A fractional model of Bioheat equation for describing quantitatively the thermal responses of skin tissue under sinusoidal heat flux conditions on skin surface is given. Laplace transform technique is used to obtain the solution in a closed form. The resulting formulation is applied to one-dimensional application to investigate the temperature distribution in skin with instantaneous surface heating for different cases. According to the numerical results and its graphs, conclusion about the fractional bioheat transfer equation has been constructed. Sensitivity analysis is performed to explore the thermal effects of various control parameters on tissue temperature. The comparisons are made with the results obtained in the case of the absence of time-fractional order. © 2016 Japanese Society of Animal Science. © 2016 Japanese Society of Animal Science.

Study on the dose distribution of the mixed field with thermal and epi-thermal neutrons for neutron capture therapy

International Nuclear Information System (INIS)

Kobayashi, Tooru; Sakurai, Yoshinori; Kanda, Keiji

1994-01-01

Simulation calculations using DOT 3.5 were carried out in order to confirm the characteristics of depth-dependent dose distribution in water phantom dependent on incident neutron energy. The epithermal neutrons mixed to thermal neutron field is effective improving the thermal neutron depth-dose distribution for neutron capture therapy. A feasibility study on the neutron energy spectrum shifter was performed using ANISN-JR for the KUR Heavy Water Facility. The design of the neutron spectrum shifter is feasible, without reducing the performance as a thermal neutron irradiation field. (author)

Point-of-care instrument for monitoring tissue health during skin graft repair

Science.gov (United States)

Gurjar, R. S.; Seetamraju, M.; Zhang, J.; Feinberg, S. E.; Wolf, D. E.

2011-06-01

We have developed the necessary theoretical framework and the basic instrumental design parameters to enable mapping of subsurface blood dynamics and tissue oxygenation for patients undergoing skin graft procedures. This analysis forms the basis for developing a simple patch geometry, which can be used to map by diffuse optical techniques blood flow velocity and tissue oxygenation as a function of depth in subsurface tissue.skin graft, diffuse correlation analysis, oxygen saturation.

Thermal wave propagation in blood perfused tissues under hyperthermia treatment for unique oscillatory heat flux at skin surface and appropriate initial condition

Science.gov (United States)

Dutta, Jaideep; Kundu, Balaram

2018-05-01

This paper aims to develop an analytical study of heat propagation in biological tissues for constant and variable heat flux at the skin surface correlated with Hyperthermia treatment. In the present research work we have attempted to impose two unique kind of oscillating boundary condition relevant to practical aspect of the biomedical engineering while the initial condition is constructed as spatially dependent according to a real life situation. We have implemented Laplace's Transform method (LTM) and Green Function (GFs) method to solve single phase lag (SPL) thermal wave model of bioheat equation (TWMBHE). This research work strongly focuses upon the non-invasive therapy by employing oscillating heat flux. The heat flux at the skin surface is considered as constant, sinusoidal, and cosine forms. A comparative study of the impact of different kinds of heat flux on the temperature field in living tissue explored that sinusoidal heat flux will be more effective if the time of therapeutic heating is high. Cosine heating is also applicable in Hyperthermia treatment due to its precision in thermal waveform. The result also emphasizes that accurate observation must be required for the selection of phase angle and frequency of oscillating heat flux. By possible comparison with the published experimental research work and published mathematical study we have experienced a difference in temperature distribution as 5.33% and 4.73%, respectively. A parametric analysis has been devoted to suggest an appropriate procedure of the selection of important design variables in viewpoint of an effective heating in hyperthermia treatment.

Use of fractional laser microablation of skin for improvement of its immersion clearing

Science.gov (United States)

Kolesnikova, Ekaterina A.; Kolesnikov, Aleksandr S.; Genina, Elina A.; Dolotov, Leonid E.; Tuchina, Darya K.; Bashkatov, Alexey N.; Tuchin, Valery V.

2013-02-01

We are proposing a new method for enhancement of optical clearing agent delivery into the skin using fractional laser microablation of the skin surface. The Palomar Lux2940 erbium laser with the wavelength 2940 nm and pulse duration of 5 ms was used as a light source. Two regimes of laser action were used in the experiments: the first one realized microablation of skin upper layer and the second one created microchannels in skin. As optical clearing agents mineral oil and PEG-300 were used. In vivo studies were carried out with white outbred rats. Both parameters: the permeability coefficient of the agents in the tissue and the optical probing depth were measured using the OCT system at a wavelength of 930 nm. The following values of the permeability coefficient of the skin with microablation were obtained: (3.41+/-0.46)×10-5 cm/s and (2.35+/-0.30)×10-5 cm/s for mineral oil and PEG-300, respectively, at the use of the surface microablation and (3.32+/-0.09)×10-5 cm/s and (3.61+/-0.34)×10-5 cm/s for mineral oil and PEG-300, respectively, at the use of the microporation. The results have shown that the joint application of mineral oil with microablation in the first regime promotes maximal (nearly 2-folds) increasing of optical probing depth in 30 min. Obtained data can be used for development of optical diagnostic methods of skin diseases.

In vitro investigation of the follicular penetration of porcine ear skin using a nanoparticle-emulsion containing the antiseptic polihexanide

International Nuclear Information System (INIS)

Ulmer, M; Patzelt, A; Lademann, J; Richter, H; Sterry, W; Lange-Asschenfeldt, B; Vergou, T; Kramer, A; Mueller, G

2012-01-01

Earlier investigations regarding the distribution of the bacterial flora on the human skin demonstrate that the hair follicle acts as a bacterial reservoir, providing a quick source for secondary recontamination. These findings highlight the importance of the hair follicle as a target for modern antiseptics. In the present study, we have assessed the follicular penetration of a curcumin-labeled particle-associated antiseptic into porcine skin by laser scanning microscopy. Therefore, the follicular penetration depth of the curcumin-labeled particle-associated antiseptic was compared to the follicular penetration depth of curcumin-labeled particles without antiseptic. The investigation was performed in vitro using porcine skin biopsies. By superposition of the images acquired in the transmission and the fluorescent modus, it was possible to visualize the distribution of the fluorescent dye inside the hair follicles. Quantitative and qualitative results showed that both dispersions penetrated efficiently into the hair follicles. The average penetration depth of the particles with attached antiseptic polihexanide was significantly higher than that of particles without the attached antiseptic. Also, whilst very little sample preparation was needed, laser scanning microscopy was found to be an efficient tool to visualize the skin relief and in particular the hair follicle shaft and localize fluorescent markers within the skin tissue and hair follicles

Erbium-yttrium-aluminum-garnet laser irradiation ameliorates skin permeation and follicular delivery of antialopecia drugs.

Science.gov (United States)

Lee, Woan-Ruoh; Shen, Shing-Chuan; Aljuffali, Ibrahim A; Li, Yi-Ching; Fang, Jia-You

2014-11-01

Alopecia usually cannot be cured because of the available drug therapy being unsatisfactory. To improve the efficiency of treatment, erbium-yttrium-aluminum-garnet (Er-YAG) laser treatment was conducted to facilitate skin permeation of antialopecia drugs such as minoxidil (MXD), diphencyprone (DPCP), and peptide. In vitro and in vivo percutaneous absorption experiments were carried out by using nude mouse skin and porcine skin as permeation barriers. Fluorescence and confocal microscopies were used to visualize distribution of permeants within the skin. Laser ablation at a depth of 6 and 10 μm enhanced MXD skin accumulation twofold to ninefold depending on the skin barriers selected. DPCP absorption showed less enhancement by laser irradiation as compared with MXD. An ablation depth of 10 μm could increase the peptide flux from zero to 4.99 and 0.33 μg cm(-2) h(-1) for nude mouse skin and porcine skin, respectively. The laser treatment also promoted drug uptake in the hair follicles, with DPCP demonstrating the greatest enhancement (sixfold compared with the control). The imaging of skin examined by microscopies provided evidence of follicular and intercellular delivery assisted by the Er-YAG laser. Besides the ablative effect of removing the stratum corneum, the laser may interact with sebum to break up the barrier function, increasing the skin delivery of antialopecia drugs. The minimally invasive, well-controlled approach of laser-mediated drug permeation offers a potential way to treat alopecia. This study's findings provide the basis for the first report on laser-assisted delivery of antialopecia drugs. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Allogeneic cultured keratinocytes vs. cadaveric skin to cover wide-mesh autogenous split-thickness skin grafts.

Science.gov (United States)

Monstrey, S; Beele, H; Kettler, M; Van Landuyt, K; Blondeel, P; Matton, G; Naeyaert, J M

1999-09-01

Improved shock therapy has extended the limits of survival in patients with massive burns, and nowadays skin coverage has become the major problem in burn management. The use of mesh skin grafts is still the simplest technique to expand the amount of available donor skin. However, very wide-mesh skin grafts take a very long time to heal, often resulting in unaesthetic scar formation. On the other hand, allogeneic cultured keratinocytes have been reported as a natural source of growth factors and thus could be useful to improve wound healing of these wide-mesh grafts. A clinical study was performed to compare the use of cryopreserved allogeneic cultured keratinocytes vs. the traditional cadaveric skin as a double layer over widely expanded autogenous skin grafts. This procedure was performed in 18 pairs of full-thickness burn wounds (with similar depth and location) in 11 severely burned patients. Early clinical evaluation was made at 2, 3, and 4 to 5 weeks. Parameters such as epithelialization, granulation tissue formation, infection, and scar formation were evaluated. Biopsies were taken to compare the histological characteristics of the epidermis, the epidermal-dermal junction, and the dermis. Late evaluations were performed at 6 and 12 months regarding color, softness, thickness, and subjective feeling of the scar tissue. Aside from a faster (p keratinocyte group at 2 weeks, there were no statistically different results in any of the early evaluated parameters, neither clinically nor histologically. At long-term follow-up, clinical results and scar characteristics were not significantly different in the two compared groups. It is concluded from the results of this study that, during the early phase, epithelialization was faster with allogeneic cultured keratinocytes compared with cadaveric skin. However, taking into account the substantial difference in costs, the described use of cryopreserved allogeneic cultured keratinocytes as a double layer on meshed

Fractional nonablative laser resurfacing: is there a skin tightening effect?

Science.gov (United States)

Kauvar, Arielle N B

2014-12-01

Fractional photothermolysis, an approach to laser skin resurfacing that creates microscopic thermal wounds in skin separated by islands of spared tissue, was developed to overcome the high incidence of adverse events and prolonged healing times associated with full coverage ablative laser procedures. To examine whether fractional nonablative laser resurfacing induces skin tightening. A literature review was performed to evaluate the clinical and histologic effects of fractional nonablative laser resurfacing and full coverage ablative resurfacing procedures. Fractional nonablative lasers produce excellent outcomes with minimal risk and morbidity for a variety of clinical conditions, including photodamaged skin, atrophic scars, surgical and burn scars. Efforts to induce robust fibroplasia in histologic specimens and skin tightening in the clinical setting have yielded inconsistent results. A better understanding of the histology of fractional laser resurfacing will help to optimize clinical outcomes.

Analysis and reduction of thermal magnetic noise in liquid-He dewar for sensitive low-field nuclear magnetic resonance measurements

International Nuclear Information System (INIS)

Hwang, S. M.; Yu, K. K.; Lee, Y. H.; Kang, C. S.; Kim, K.; Lee, S. J.

2013-01-01

For sensitive measurements of micro-Tesla nuclear magnetic resonance (μT-NMR) signal, a low-noise superconducting quantum interference device (SQUID) system is needed. We have fabricated a liquid He dewar for an SQUID having a large diameter for the pickup coil. The initial test of the SQUID system showed much higher low-frequency magnetic noise caused by the thermal magnetic noise of the aluminum plates used for the vapor-cooled thermal shield material. The frequency dependence of the noise spectrum showed that the noise increases with the decrease of frequency. This behavior could be explained from a two-layer model; one generating the thermal noise and the other one shielding the thermal noise by eddy-current shielding. And the eddy-current shielding effect is strongly dependent on the frequency through the skin-depth. To minimize the loop size for the fluctuating thermal noise current, we changed the thermal shield material into insulated thin Cu mesh. The magnetic noise of the SQUID system became flat down to 0.1 Hz with a white noise of 0.3 fT√ Hz, including the other noise contributions such as SQUID electronics and magnetically shielded room, etc, which is acceptable for low-noise μT-NMR experiments.

Quantum dot imaging in the second near-infrared optical window: studies on reflectance fluorescence imaging depths by effective fluence rate and multiple image acquisition

Science.gov (United States)

Jung, Yebin; Jeong, Sanghwa; Nayoun, Won; Ahn, Boeun; Kwag, Jungheon; Geol Kim, Sang; Kim, Sungjee

2015-04-01

Quantum dot (QD) imaging capability was investigated by the imaging depth at a near-infrared second optical window (SOW; 1000 to 1400 nm) using time-modulated pulsed laser excitations to control the effective fluence rate. Various media, such as liquid phantoms, tissues, and in vivo small animals, were used and the imaging depths were compared with our predicted values. The QD imaging depth under excitation of continuous 20 mW/cm2 laser was determined to be 10.3 mm for 2 wt% hemoglobin phantom medium and 5.85 mm for 1 wt% intralipid phantom, which were extended by more than two times on increasing the effective fluence rate to 2000 mW/cm2. Bovine liver and porcine skin tissues also showed similar enhancement in the contrast-to-noise ratio (CNR) values. A QD sample was inserted into the abdomen of a mouse. With a higher effective fluence rate, the CNR increased more than twofold and the QD sample became clearly visualized, which was completely undetectable under continuous excitation. Multiple acquisitions of QD images and averaging process pixel by pixel were performed to overcome the thermal noise issue of the detector in SOW, which yielded significant enhancement in the imaging capability, showing up to a 1.5 times increase in the CNR.

General considerations of the choice of dose limits, averaging areas and weighting factors for the skin in the light of revised skin cancer risk figures and experimental data on non-stochastic effects

International Nuclear Information System (INIS)

Charles, M.W.

1990-01-01

Recent biological data from man and pig on the non-stochastic effects following exposure with a range of β-emitters are combined with recent epidemiological analyses of skin cancer risks in man to form a basis for suggested improved protection criteria following whole- or partial-body skin exposures. Specific consideration is given to the choice of an organ weighting factor for evaluation of effective dose-equivalent. Since stochastic and non-stochastic end-points involve different cell types at different depths in the skin, the design of an ideal physical dosemeter may depend on the proportion of the body skin exposed and the radiation penetrating power. Possible choices of design parameters for skin dosemeters are discussed. Limitation of skin exposure from small radioactive sources ('hot particles') is addressed using animal data. (author)

The influence of outdoor thermal environment on young Japanese females

Science.gov (United States)

Kurazumi, Yoshihito; Ishii, Jin; Kondo, Emi; Fukagawa, Kenta; Bolashikov, Zhecho Dimitrov; Sakoi, Tomonori; Tsuchikawa, Tadahiro; Matsubara, Naoki; Horikoshi, Tetsumi

2014-07-01

The influence of short wave solar radiation appears to be strong outdoors in summer, and the influence of airflow appears to be strong outdoors in winter. The purpose of this paper was to clarify the influence of the outdoor environment on young Japanese females. This research shows the relationship between the physiological and psychological responses of humans and the enhanced conduction-corrected modified effective temperature (ETFe). Subjective experiments were conducted in an outdoor environment. Subjects were exposed to the thermal environment in a standing posture. Air temperature, humidity, air velocity, short wave solar radiation, long wave radiation, ground surface temperature, sky factor, and the green solid angle were measured. The temperatures of skin exposed to the atmosphere and in contact with the ground were measured. Thermal sensation and thermal comfort were measured by means of rating the whole-body thermal sensation (cold-hot) and the whole body thermal comfort (comfortable-uncomfortable) on a linear scale. Linear rating scales are given for the hot (100) and cold (0), and comfortable (100) and uncomfortable (0) directions only. Arbitrary values of 0 and 100 were assigned to each endpoint, the reported values read in, and the entire length converted into a numerical value with an arbitrary scale of 100 to give a linear rating scale. The ETFe considered to report a neither hot nor cold, thermally neutral sensation of 50 was 35.9 °C, with 32.3 °C and 42.9 °C, respectively, corresponding to the low and high temperature ends of the ETFe considered to report a neither comfortable nor uncomfortable comfort value of 50. The mean skin temperature considered to report a neither hot nor cold, thermally neutral sensation of 50 was 33.3 °C, with 31.0 °C and 34.3 °C, respectively, corresponding to the low and high temperature ends of the mean skin temperature considered to report a neither comfortable nor uncomfortable comfort value of 50. The

Studies on the relationship between epidermal cell turnover kinetics and permeability of hairless mouse skin

International Nuclear Information System (INIS)

Han, S.R.

1988-01-01

The primary aim of this study was to develop non-invasive, physical means to quantitatively assess the epidermal turnover kinetics and barrier properties of the skin and relate these to the cutaneous irritation which results from ultraviolet light irradiation and mold thermal burns. After systematically injecting radiolabeled glycine, the appearance of radioactivity at the skin's surface indicated the transit time of radiolabeled cells through the skin. By plotting the data as the cumulative specific activity against time and then fitting them with a third order polynomial equation, it is possible to estimate the turnover time of the stratum corneum. The skin turnover was coordinated with non-invasive transepidermal water loss (TEWL) studies determined with an evaporimeter. In vitro diffusion studies of the permeability of hydrocortisone through UVB irradiated and thermally burned skin were also performed. The studies indicated that irritated skin offers a relatively low diffusional resistance to hydrocortisone. Depending on the severity of the trauma, the increases in hydrocortisone's permeability coefficient through irritated skin ranged from a low of about 2 times normal to a high of about 210 times normal. Trauma-induced changes in hydrocortisone permeability parallel changes in TEWL, proving that the barrier deficient state resulting from rapid epidermal turnover is a general phenomenon

Optimal operation of a south double-skin facade

Energy Technology Data Exchange (ETDEWEB)

Gratia, E.; De Herde, A. [Universite Catholique de Louvain (Belgium). Architecture et Climat

2004-01-01

There is an increasing demand for higher quality office buildings. Occupants and developers of office buildings ask for a healthy and stimulating working environment. Double-skin facades are appropriate when buildings are subject to great external noise and wind loads. A further area of application is in rehabilitation work, when existing facades cannot be renewed, or where this is not desirable. Double-skin facades have a special esthetic of their own, and this can be exploited architecturally to great advantage. However there are still relatively few buildings in which double-skin facades have actually been realized, and there is still too little experience of their behaviour in operation. In this matter, we choose to study a multi-storey double-skin facades behaviour. Simulations were realized with TAS software on the building proposed in the frame of the subtask A of the Task 27 (performance of solar facade components) of the International Energy Agency. Simulations were performed on the chosen building with and without double-skin facades. We decide to study eight types of days; and we analyze the double-skin facade behaviour for various operations. The thermal behaviours of the building with and without double-skin are compared. The study of these eight cases showed the importance of the dynamic use of the double-skin. The operation of this one must be obligatorily related to the climatic conditions as well external as interior and a bad operation of the double-skin could lead to catastrophic results. (author)

Noxious heat and scratching decrease histamine-induced itch and skin blood flow.

Science.gov (United States)

Yosipovitch, Gil; Fast, Katharine; Bernhard, Jeffrey D

2005-12-01

The aim of this study was to assess the effect of thermal stimuli or distal scratching on skin blood flow and histamine-induced itch in healthy volunteers. Twenty-one healthy volunteers participated in the study. Baseline measurements of skin blood flow were obtained on the flexor aspect of the forearm. These measurements were compared with skin blood flow after various stimuli: heating the skin, cooling the skin, noxious cold 2 degrees C, noxious heat 49 degrees C, and scratching via a brush with controlled pressure. Afterwards histamine iontophoresis was performed and skin blood flow and itch intensity were measured immediately after the above-mentioned stimuli. Scratching reduced mean histamine-induced skin blood flow and itch intensity. Noxious heat pain increased basal skin blood flow but reduced histamine-induced maximal skin blood flow and itch intensity. Cold pain and cooling reduced itch intensity, but neither affected histamine-induced skin blood flow. Sub-noxious warming the skin did not affect the skin blood flow or itch intensity. These findings suggest that heat pain and scratching may inhibit itch through a neurogenic mechanism that also affects skin blood flow.

Anomalous Skin Effect for Anisotropic Electron Velocity Distribution Function

International Nuclear Information System (INIS)

Igor Kaganovich; Edward Startsev; Gennady Shvets

2004-01-01

The anomalous skin effect in a plasma with a highly anisotropic electron velocity distribution function (EVDF) is very different from skin effect in a plasma with the isotropic EVDF. An analytical solution was derived for the electric field penetrated into plasma with the EVDF described as a Maxwellian with two temperatures Tx >> Tz, where x is the direction along the plasma boundary and z is the direction perpendicular to the plasma boundary. The skin layer was found to consist of two distinctive regions of width of order nTx/w and nTz/w, where nTx,z/w = (Tx,z/m)1/2 is the thermal electron velocity and w is the incident wave frequency

Visualization of the microcirculatory network in skin by high frequency optoacoustic mesoscopy

Science.gov (United States)

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

2015-07-01

Optoacoustic (photoacoustic) imaging has a high potential for imaging melanin-rich structures in skin and the microvasculature of the dermis due to the natural chromophores (de)oxyhemoglobin, and melanin. The vascular network in human dermis comprises a large network of arterioles, capillaries, and venules, ranging from 5 μm to more than 100 μm in diameter. The frequency spectrum of the microcirculatory network in human skin is intrinsically broadband, due to the large variety in size of absorbers. In our group we have developed raster-scan optoacoustic mesoscopy (RSOM) that applies a 100 MHz transducer with ultra-wide bandwidth in raster-scan mode achieving lateral resolution of 18 μm. In this study, we applied high frequency RSOM to imaging human skin in a healthy volunteer. We analyzed the frequency spectrum of anatomical structures with respect to depth and show that frequencies >60 MHz contain valuable information of structures in the epidermis and the microvasculature of the papillary dermis. We illustrate that RSOM is capable of visualizing the fine vascular network at and beneath the epidermal-dermal junction, revealing the vascular fingerprint of glabrous skin, as well as the larger venules deeper inside the dermis. We evaluate the ability of the RSOM system in measuring epidermal thickness in both hairy and glabrous skin. Finally, we showcase the capability of RSOM in visualizing benign nevi that will potentially help in imaging the penetration depth of melanoma.

Development of Cold Neutron Depth Profiling System at HANARO

International Nuclear Information System (INIS)

Park, B. G.; Choi, H. D.; Sun, G. M.

2012-01-01

The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. A number of analytical techniques for depth profiling have been developed. Neutron Depth Profiling (NDP) system which was developed by Ziegler et al. is one of the leading analytical techniques. In NDP, a thermal or cold neutron beam passes through a material and interacts with certain isotopes that are known to emit monoenergetic-charged particle remaining a recoil nucleus after neutron absorption. The depth is obtained from the energy loss of those charged particles escaping surface of substrate material. For various applications of NDP technique, the Cold Neutron Depth Profiling System (CN-NDP) was developed at a neutron guide CG1 installed at the HANARO cold neutron source. In this study the design features of the cold neutron beam and target chamber for the CN-NDP system are given. Also, some experiments for the performance tests of the CN-NDP system are described

Long-term three-dimensional volumetric assessment of skin tightening using a sharply tapered non-insulated microneedle radiofrequency applicator with novel fractionated pulse mode in asians.

Science.gov (United States)

Tanaka, Yohei

2015-10-01

Non-insulated microneedle radiofrequency (NIMNRF) is a novel method that allows non-thermal penetration of the epidermis followed by radiofrequency (RF) coagulation at selected depths of the dermis that are surrounded by a zone of non-coagulative volumetric heating. The objective of this study was to investigate subjectively and objectively the efficacy of a single fractional NIMNRF treatment. Twenty Japanese patients underwent full face skin tightening using a sharply tapered NIMNRF applicator with a novel fractionated pulse mode. The system platform (1MHZ) incorporated six independent phase controlled RF generators coupled to RF microneedles that induced skin remodeling via controlled dermal coagulation. Patients received from 500 to 1000 pulses that were 80-110 milliseconds in duration at a power of 10-14 W, and a 1.5-2.5 mm penetration depth. Topical anesthetic cream was applied before the treatment. Monthly three-dimensional (3-D) volumetric assessments were performed for 6 months after treatment. Patients rated their satisfaction using a 5-point scale. During the study patients showed significant skin tightening on the lower two-thirds of the face. Objective assessments with superimposed 3-D color images showed significant median volumetric reduction of 12.1 ml at 6 months post-treatment. Ninety percent of the patients were either "satisfied" or "very satisfied" with the treatment results. The treatments were well tolerated with minimal discomfort. Complications included a slight burning sensation and mild erythema that were minor and transitory; both resolved within 5 hours. Side effects such as post-inflammatory hyperpigmentation, epidermal burns, and scar formation were not observed. The advantages of this NIMNRF treatment for skin tightening are its long-lasting high efficacy as shown through 3-D volumetric assessments. Moreover, NIMNRF produced minimal complications and downtime as well as few side effects. This non-invasive novel fractional NIMNRF

Phase change thermal control materials, method and apparatus

Science.gov (United States)

Buckley, Theresa M. (Inventor)

2001-01-01

An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Quantification of changes in skin hydration and sebum after tape stripping using infrared spectroscopy

Science.gov (United States)

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

2017-02-01

Skin barrier function relies on well balanced water and lipid system of stratum corneum. Optimal hydration and oiliness levels are indicators of skin health and integrity. We demonstrate an accurate and sensitive depth profiling of stratum corneum sebum and hydration levels using short wave infrared spectroscopy in the spectral range around 1720 nm. We demonstrate that short wave infrared spectroscopic technique combined with tape stripping can provide morequantitative and more reliable skin barrier function information in the low hydration regime, compared to conventional biophysical methods.

Transport lattice models of heat transport in skin with spatially heterogeneous, temperature-dependent perfusion

Directory of Open Access Journals (Sweden)

Martin Gregory T

2004-11-01

Full Text Available Abstract Background Investigation of bioheat transfer problems requires the evaluation of temporal and spatial distributions of temperature. This class of problems has been traditionally addressed using the Pennes bioheat equation. Transport of heat by conduction, and by temperature-dependent, spatially heterogeneous blood perfusion is modeled here using a transport lattice approach. Methods We represent heat transport processes by using a lattice that represents the Pennes bioheat equation in perfused tissues, and diffusion in nonperfused regions. The three layer skin model has a nonperfused viable epidermis, and deeper regions of dermis and subcutaneous tissue with perfusion that is constant or temperature-dependent. Two cases are considered: (1 surface contact heating and (2 spatially distributed heating. The model is relevant to the prediction of the transient and steady state temperature rise for different methods of power deposition within the skin. Accumulated thermal damage is estimated by using an Arrhenius type rate equation at locations where viable tissue temperature exceeds 42°C. Prediction of spatial temperature distributions is also illustrated with a two-dimensional model of skin created from a histological image. Results The transport lattice approach was validated by comparison with an analytical solution for a slab with homogeneous thermal properties and spatially distributed uniform sink held at constant temperatures at the ends. For typical transcutaneous blood gas sensing conditions the estimated damage is small, even with prolonged skin contact to a 45°C surface. Spatial heterogeneity in skin thermal properties leads to a non-uniform temperature distribution during a 10 GHz electromagnetic field exposure. A realistic two-dimensional model of the skin shows that tissue heterogeneity does not lead to a significant local temperature increase when heated by a hot wire tip. Conclusions The heat transport system model of the

Nonablative fractional laser resurfacing in Asian skin--a review.

Science.gov (United States)

Sachdeva, Silonie

2010-12-01

Skin resurfacing has been a part of cosmetic dermatology for more than two decades now, and most of it has been ablative with traditional aggressive lasers including the CO(2) and erbium. The last few years have seen a revolutionary change with the invention of nonablative lasers for skin tightening. Fractional resurfacing is a new concept of cutaneous remodeling whereby laser-induced zones of microthermal injury are surrounded by normal untreated tissue that helps in quicker healing. The various wavelengths used are 1320, 1440, and 2940 nm with depth of penetration ranging from 25 μ to 1.2 mm. This article reviews the history of nonablative fractional laser resurfacing, its indications, contraindications, and a review of use in Asian skin with Fitzpatrick type III-VI. © 2010 Wiley Periodicals, Inc.

Human thermal sensation and comfort in a non-uniform environment with personalized heating.

Science.gov (United States)

Deng, Qihong; Wang, Runhuai; Li, Yuguo; Miao, Yufeng; Zhao, Jinping

2017-02-01

Thermal comfort in traditionally uniform environment is apparent and can be improved by increasing energy expenses. To save energy, non-uniform environment implemented by personalized conditioning system attracts considerable attention, but human response in such environment is unclear. To investigate regional- and whole-body thermal sensation and comfort in a cool environment with personalized heating. In total 36 subjects (17 males and 19 females) including children, adults and the elderly, were involved in our experiment. Each subject was first asked to sit on a seat in an 18°C chamber (uniform environment) for 40min and then sit on a heating seat in a 16°C chamber (non-uniform environment) for another 40min after 10min break. Subjects' regional- and whole-body thermal sensation and comfort were surveyed by questionnaire and their skin temperatures were measured by wireless sensors. We statistically analyzed subjects' thermal sensation and comfort and their skin temperatures in different age and gender groups and compared them between the uniform and non-uniform environments. Overall thermal sensation and comfort votes were respectively neutral and just comfortable in 16°C chamber with personalized heating, which were significantly higher than those in 18°C chamber without heating (pthermal sensation and comfort was consistent in subjects of different age and gender. However, adults and the females were more sensitive to the effect of personalized heating and felt cooler and less comfort than children/elderly and the males respectively. Variations of the regional thermal sensation/comfort across human body were consistent with those of skin temperature. Personalized heating significantly improved human thermal sensation and comfort in non-uniform cooler environment, probably due to the fact that it increased skin temperature. However, the link between thermal sensation/comfort and variations of skin temperature is rather complex and warrant further

Application of waterproof breathable fabric in thermal protective clothing exposed to hot water and steam

Science.gov (United States)

Su, Y.; Li, R.; Song, G.; Li, J.

2017-10-01

A hot water and steam tester was used to examine thermal protective performance of waterproof and breathable fabric against hot water and steam hazards. Time to cause skin burn and thermal energy absorbed by skin during exposure and cooling phases was employed to characterize the effect of configuration, placing order and properties of waterproof and breathable fabric on the thermal protective performance. The difference of thermal protective performance due to hot water and steam hazards was discussed. The result showed that the configuration of waterproof and breathable fabric presented a significant effect on the thermal protective performance of single- and double-layer fabric system, while the difference between different configurations in steam hazard was greater than that in hot water hazard. The waterproof and breathable fabric as outer layer provided better protection than that as inner layer. Increasing thickness and moisture regain improved the thermal protective performance of fabric system. Additionally, the thermal energy absorbed by skin during the cooling phase was affected by configuration, thickness and moisture regain of fabric. The findings will provide technical data to improve performance of thermal protective clothing in hot water and steam hazards.

Under Water Thermal Cutting of the Moderator Vessel and Thermal Shield

International Nuclear Information System (INIS)

Loeb, A.; Sokcic-Kostic, M.; Eisenmann, B.; Prechtl, E.

2007-01-01

This paper presents the segmentation of the in 8 meter depth of water and for cutting through super alloyed moderator vessel and of the thermal shield of the MZFR stainless steel up to 130 mm wall thickness. Depending on the research reactor by means of under water plasma and contact arc metal cutting. The moderator vessel and the thermal shield are the most essential parts of the MZFR reactor vessel internals. These components have been segmented in 2005 by means of remotely controlled under water cutting utilizing a special manipulator system, a plasma torch and CAMC (Contact Arc Metal Cutting) as cutting tools. The engineered equipment used is a highly advanced design developed in a two years R and D program. It was qualified to cut through steel walls of more than 100 mm thickness in 8 meters water depth. Both the moderator vessel and the thermal shield had to be cut into such size that the segments could afterwards be packed into shielded waste containers each with a volume of roughly 1 m 3 . Segmentation of the moderator vessel and of the thermal shield was performed within 15 months. (author)

All Organic Polymers Based Morphing Skin with Controllable Surface Texture

KAUST Repository

Favero Bolson, Natanael

2018-05-01

Smart skins are integrating an increasing number of functionalities in order to improve the interaction between the systems they equip and their ambient environment. Here we have developed an electromechanical soft actuator with controlled surface texture due to applied thermal gradient via electrical voltage. The device was fabricated and integrated with optimized process parameters for a prepared heater element [doped PEDOT: PSS (poly-(3, 4 ethylenedioxythiophene): poly (styrene sulfonic acid))], a soft actuator (Ecoflex 00-50/ethanol) and overall packaging case [PDMS (polydimethylsiloxane)]. To study a potential application of the proposed smart skin, we analyze the fluid drag reduction in a texture controlled water flow unit. As a result, we obtained a reduction of approximately 14% in the skin drag friction coefficient during the actuation. We conclude that the proposed soft actuator device is a preferred option for a texture-controlled skin that reduces the skin drag friction coefficient.

Shave-off depth profiling: Depth profiling with an absolute depth scale

International Nuclear Information System (INIS)

Nojima, M.; Maekawa, A.; Yamamoto, T.; Tomiyasu, B.; Sakamoto, T.; Owari, M.; Nihei, Y.

2006-01-01

Shave-off depth profiling provides profiling with an absolute depth scale. This method uses a focused ion beam (FIB) micro-machining process to provide the depth profile. We show that the shave-off depth profile of a particle reflected the spherical shape of the sample and signal intensities had no relationship to the depth. Through the introduction of FIB micro-sampling, the shave-off depth profiling of a dynamic random access memory (DRAM) tip was carried out. The shave-off profile agreed with a blue print from the manufacturing process. Finally, shave-off depth profiling is discussed with respect to resolutions and future directions

Technical specification of the NRPB thermoluminescent dosemeter used for the measurement of body dose and skin dose

CERN Document Server

Shaw, K B

1977-01-01

This report specifies the NRPB thermoluminescent dosemeter used for the measurement of radiation dose in tissue at a depth of 700 mg cm sup - sup 2 (body dose) and at a depth of 5-10 mg cm sup - sup 2 (skin dose).

Properties and Types of Significant Thermal Skin Burn Injuries

Science.gov (United States)

2018-02-01

The deep burn category includes deep second, deep third and deep fourth-degree burns. Table 2: Burn Classification and Injury Outcome ( Rice ...Subcutaneous tissue  Entire dermis destroyed  No to low pain due to nerve destruction  Waxy white to leathery gray to charred black skin  Dry...Richard R.L. (2009) Rehabilitation of the Burned Hand. Hand Clinics, 25, 529- 541 Rice P.L. & Orgill, D.P. (2015).Classification of burns. (Ed

The contribution of skin blood flow in warming the skin after the application of local heat; the duality of the Pennes heat equation.

Science.gov (United States)

Petrofsky, Jerrold; Paluso, Dominic; Anderson, Devyn; Swan, Kristin; Yim, Jong Eun; Murugesan, Vengatesh; Chindam, Tirupathi; Goraksh, Neha; Alshammari, Faris; Lee, Haneul; Trivedi, Moxi; Hudlikar, Akshay N; Katrak, Vahishta

2011-04-01

As predicted by the Pennes equation, skin blood flow is a major contributor to the removal of heat from an external heat source. This protects the skin from erythema and burns. But, for a person in a thermally neutral room, the skin is normally much cooler than arterial blood. Therefore, if skin blood flow (BF) increases, it should initially warm the skin paradoxically. To examine this phenomenon, 10 young male and female subjects participated in a series of experiments to examine the contribution of skin blood flow in the initial warming the skin after the application of local heat. Heat flow was measured by the use of a thermode above the brachioradialis muscle. The thermode was warmed by constant temperature water at 44°C entering the thermode at a water flow rate of 100 cm(3)/min. Skin temperature was measured by a thermistor and blood flow in the underlying skin was measured by a laser Doppler imager in single point mode. The results of the experiments showed that, when skin temperature is cool (31-32°C), the number of calories being transferred to the skin from the thermode cannot account for the rise in skin temperature alone. A significant portion of the rise in skin temperature is due to the warm arterialized blood traversing the skin from the core areas of the body. However, as skin temperature approaches central core temperature, it becomes less of a heat source and more of a heat sync such that when skin temperature is at or above core temperature, the blood flow to the skin, as predicted by Pennes, becomes a heat sync pulling heat from the thermode. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

Medical diagnosis system and method with multispectral imaging. [depth of burns and optical density of the skin

Science.gov (United States)

Anselmo, V. J.; Reilly, T. H. (Inventor)

1979-01-01

A skin diagnosis system includes a scanning and optical arrangement whereby light reflected from each incremental area (pixel) of the skin is directed simultaneously to three separate light filters, e.g., IR, red, and green. As a result, the three devices simultaneously produce three signals which are directly related to the reflectance of light of different wavelengths from the corresponding pixel. These three signals for each pixel after processing are used as inputs to one or more output devices to produce a visual color display and/or a hard copy color print, for one usable as a diagnostic aid by a physician.

MR determination of neonatal spinal canal depth.

Science.gov (United States)

Arthurs, Owen; Thayyil, Sudhin; Wade, Angie; Chong, W K Kling; Sebire, Neil J; Taylor, Andrew M

2012-08-01

Lumbar punctures (LPs) are frequently performed in neonates and often result in traumatic haemorrhagic taps. Knowledge of the distance from the skin to the middle of the spinal canal (mid-spinal canal depth - MSCD) may reduce the incidence of traumatic taps, but there is little data in extremely premature or low birth weight neonates. Here, we determined the spinal canal depth at post-mortem in perinatal deaths using magnetic resonance imaging (MRI). Spinal canal depth was measured in 78 post-mortem foetuses and perinatal cases (mean gestation 26 weeks; mean weight 1.04kg) at the L3/L4 inter-vertebral space at post-mortem MRI. Both anterior (ASCD) and posterior (PSCD) spinal canal depth were measured; MSCD was calculated and modelled against weight and gestational age. ASCD and PSCD (mm) correlated significantly with weight and gestational age (all r>0.8). A simple linear model MSCD (mm)=3×Weight (kg)+5 was the best fit, identifying an SCD value within the correct range for 87.2% (68/78) (95% CI (78.0, 92.9%)) cases. Gestational age did not add significantly to the predictive value of the model. There is a significant correlation between MSCD and body weight at post-mortem MRI in foetuses and perinatal deaths. If this association holds in preterm neonates, use of the formula MSCD (mm)=3×Weight (kg)+5 could result in fewer traumatic LPs in this population. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

MR determination of neonatal spinal canal depth

Energy Technology Data Exchange (ETDEWEB)

Arthurs, Owen, E-mail: owenarthurs@uk2.net [Centre for Cardiovascular MR, Great Ormond Street Hospital for Children, London WC1N 3JH (United Kingdom); Thayyil, Sudhin, E-mail: s.thayyil@ucl.ac.uk [Academic Neonatology, Institute for Women' s Health, London WC1E 6AU (United Kingdom); Wade, Angie, E-mail: a.wade@ucl.ac.uk [Centre for Paediatric Epidemiology and Biostatistics, UCL Institute of Child Health, London (United Kingdom); Chong, W.K., E-mail: Kling.Chong@gosh.nhs.uk [Paediatric Neuroradiology, Great Ormond Street Hospital for Children, London (United Kingdom); Sebire, Neil J., E-mail: Neil.Sebire@gosh.nhs.uk [Histopathology, Great Ormond Street Hospital for Children, London WC1E 6AU (United Kingdom); Taylor, Andrew M., E-mail: a.taylor76@ucl.ac.uk [Centre for Cardiovascular MR, Cardiorespiratory Unit, Great Ormond Street Hospital for Children and UCL Institute of Cardiovascular Science, London WC1E 6AU (United Kingdom)

2012-08-15

Objectives: Lumbar punctures (LPs) are frequently performed in neonates and often result in traumatic haemorrhagic taps. Knowledge of the distance from the skin to the middle of the spinal canal (mid-spinal canal depth - MSCD) may reduce the incidence of traumatic taps, but there is little data in extremely premature or low birth weight neonates. Here, we determined the spinal canal depth at post-mortem in perinatal deaths using magnetic resonance imaging (MRI). Patients and methods: Spinal canal depth was measured in 78 post-mortem foetuses and perinatal cases (mean gestation 26 weeks; mean weight 1.04 kg) at the L3/L4 inter-vertebral space at post-mortem MRI. Both anterior (ASCD) and posterior (PSCD) spinal canal depth were measured; MSCD was calculated and modelled against weight and gestational age. Results: ASCD and PSCD (mm) correlated significantly with weight and gestational age (all r > 0.8). A simple linear model MSCD (mm) = 3 Multiplication-Sign Weight (kg) + 5 was the best fit, identifying an SCD value within the correct range for 87.2% (68/78) (95% CI (78.0, 92.9%)) cases. Gestational age did not add significantly to the predictive value of the model. Conclusion: There is a significant correlation between MSCD and body weight at post-mortem MRI in foetuses and perinatal deaths. If this association holds in preterm neonates, use of the formula MSCD (mm) = 3 Multiplication-Sign Weight (kg) + 5 could result in fewer traumatic LPs in this population.

Rehealable, fully recyclable, and malleable electronic skin enabled by dynamic covalent thermoset nanocomposite.

Science.gov (United States)

Zou, Zhanan; Zhu, Chengpu; Li, Yan; Lei, Xingfeng; Zhang, Wei; Xiao, Jianliang

2018-02-01

Electronic skin (e-skin) mimicking functionalities and mechanical properties of natural skin can find broad applications. We report the first dynamic covalent thermoset-based e-skin, which is connected through robust covalent bonds, rendering the resulting devices good chemical and thermal stability at service condition. By doping the dynamic covalent thermoset with conductive silver nanoparticles, we demonstrate a robust yet rehealable, fully recyclable, and malleable e-skin. Tactile, temperature, flow, and humidity sensing capabilities are realized. The e-skin can be rehealed when it is damaged and can be fully recycled at room temperature, which has rarely, if at all, been demonstrated for e-skin. After rehealing or recycling, the e-skin regains mechanical and electrical properties comparable to the original e-skin. In addition, malleability enables the e-skin to permanently conform to complex, curved surfaces without introducing excessive interfacial stresses. These properties of the e-skin yield an economical and eco-friendly technology that can find broad applications in robotics, prosthetics, health care, and human-computer interface.

Fossil intermediate-depth earthquakes in subducting slabs linked to differential stress release

Science.gov (United States)

Scambelluri, Marco; Pennacchioni, Giorgio; Gilio, Mattia; Bestmann, Michel; Plümper, Oliver; Nestola, Fabrizio

2017-12-01

The cause of intermediate-depth (50-300 km) seismicity in subduction zones is uncertain. It is typically attributed either to rock embrittlement associated with fluid pressurization, or to thermal runaway instabilities. Here we document glassy pseudotachylyte fault rocks—the products of frictional melting during coseismic faulting—in the Lanzo Massif ophiolite in the Italian Western Alps. These pseudotachylytes formed at subduction-zone depths of 60-70 km in poorly hydrated to dry oceanic gabbro and mantle peridotite. This rock suite is a fossil analogue to an oceanic lithospheric mantle that undergoes present-day subduction. The pseudotachylytes locally preserve high-pressure minerals that indicate an intermediate-depth seismic environment. These pseudotachylytes are important because they are hosted in a near-anhydrous lithosphere free of coeval ductile deformation, which excludes an origin by dehydration embrittlement or thermal runaway processes. Instead, our observations indicate that seismicity in cold subducting slabs can be explained by the release of differential stresses accumulated in strong dry metastable rocks.

Numerical experiments on thermal convection of highly compressible fluids with variable viscosity and thermal conductivity: Implications for mantle convection of super-Earths

Science.gov (United States)

Kameyama, Masanori; Yamamoto, Mayumi

2018-01-01

We conduct a series of numerical experiments of thermal convection of highly compressible fluids in a two-dimensional rectangular box, in order to study the mantle convection on super-Earths. The thermal conductivity and viscosity are assumed to exponentially depend on depth and temperature, respectively, while the variations in thermodynamic properties (thermal expansivity and reference density) with depth are taken to be relevant for the super-Earths with 10 times the Earth's. From our experiments we identified a distinct regime of convecting flow patterns induced by the interplay between the adiabatic temperature change and the spatial variations in viscosity and thermal conductivity. That is, for the cases with strong temperature-dependent viscosity and depth-dependent thermal conductivity, a "deep stratosphere" of stable thermal stratification is formed at the base of the mantle, in addition to thick stagnant lids at their top surfaces. In the "deep stratosphere", the fluid motion is insignificant particularly in the vertical direction in spite of smallest viscosity owing to its strong dependence on temperature. Our finding may further imply that some of super-Earths which are lacking in mobile tectonic plates on their top surfaces may have "deep stratospheres" at the base of their mantles.

Fractional sunburn threshold UVR doses generate equivalent vitamin D and DNA damage in skin types I-VI, but with epidermal DNA damage gradient correlated to skin darkness.

Science.gov (United States)

Shih, Barbara B; Farrar, Mark D; Cooke, Marcus S; Osman, Joanne; Langton, Abigail K; Kift, Richard; Webb, Ann R; Berry, Jacqueline L; Watson, Rachel E B; Vail, Andy; de Gruijl, Frank R; Rhodes, Lesley E

2018-05-03

Public health guidance recommends limiting sun-exposure to sub-sunburn levels, but it's unknown whether these can gain vitamin D (for musculoskeletal health) whilst avoiding epidermal DNA damage (initiates skin cancer). Well-characterised healthy humans of all skin types (I-VI; lightest to darkest skin) were exposed to a low dose-series of solar simulated UVR of 20-80% their individual sunburn threshold dose (minimal erythemal dose, MED). Significant UVR dose-responses were seen for serum 25(OH)D and whole epidermal CPD, with as little as 0.2 MED concurrently producing 25(OH)D and CPD. Notably, fractional MEDs generated equivalent levels of whole epidermal CPD and 25(OH)D across all skin types. Crucially, we demonstrated an epidermal gradient of CPD formation strongly correlated with skin darkness (r=0.74; Pskin types, ranging from darkest skin, where high CPD levels occurred superficially with none in the germinative basal layer, through to lightest skin where CPD were induced evenly across the epidermal depth. Darker skin people can be encouraged to utilise sub-sunburn UVR-exposure to enhance their vitamin D. In lighter skin people, basal cell damage occurs concurrent with vitamin D synthesis at exquisitely low UVR levels, providing an explanation for their high skin cancer incidence; greater caution is required. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Effect of insertion depth on helical antenna performance in a muscle-equivalent phantom

Energy Technology Data Exchange (ETDEWEB)

Reeves, J W; Meeson, S; Birch, M J [Department of Clinical Physics, Royal London Hospital, 56-76 Ashfield Street, London, E1 1BB (United Kingdom)

2005-06-21

Barrett's oesophagus is considered to increase the risk of cancer 30 fold. A set of helical microwave antennas was designed to investigate their potential use in the thermal therapy of Barrett's oesophagus. For treatment, a balloon filled with muscle-equivalent material encapsulates the antenna. The effects of insertion depth and coil-spacing on the thermal distribution produced by the antennas (20-35 mm) were characterized. The 35 mm helical antenna, with a coil-spacing of 3.6 mm resulted in uniform heating for an insertion depth of 40 mm. It was observed that the resultant temperature distribution produced, by the antennas, was dependent on the insertion depth within the phantom. For all antennas studied, deeper insertion resulted in two high intensity regions, approximately 1/4 and 3/4 along the antenna length. In contrast, shallow insertion resulted in predominant tip heating with undesirable heating at the phantom entry point. However, by manipulating the coil-spacing of the helix, uniform temperature profiles were achieved for a range of insertion depths.

Tumor induction and hair follicle damage for different electron penetrations in rat skin

International Nuclear Information System (INIS)

Burns, F.J.; Sinclair, I.P.; Albert, R.E.; Vanderlaan, M.

1976-01-01

The penetration and dose of an electron beam were varied in an attempt to locate the depth in growing-phase rat skin where irradiation was most effective in inducing tumors and morphological damage to the hair follicles. The hair was plucked to initiate the growing phase of the hair cycle, and 12 days later the dorsal skin was irradiated with electrons penetrating 0.5, 1.0, or 2.0 mm at doses from 500 to 4000 rad. Differences in the curves of tumor incidence as a function of dose for different penetrations were best resolved by plotting the results against the 0.4 mm dose, while comparable curves for destruction of the follicles were best resolved by the 0.8 mm dose. Since 0.8 mm corresponded approximately to the depth of the follicles, these results indicated that the target tissues for follicular damage and tumor induction were separated in depth and that the target for tumor induction was probably located in the region above or near the midpoint of the follicles. When the radiation penetrated sufficiently to reach the entire follicle, the number of tumors produced was not significantly greater than the number observed previously in resting-phase skin, and it was inferred that the additional size and greater mitotic activity of the growing-phase follicles at the time of irradiation did not increase the probability of tumor induction

Crack propagation under thermal cycling loading inducing a thermal gradient in the specimen thickness

International Nuclear Information System (INIS)

Le, H.N.

2009-05-01

This study aims to figure out the crack growth phenomenon by thermal fatigue induced by thermal gradient through thickness of specimen. Firstly, an experimental facility has been developed: a rectangular parallelepiped specimen is subjected to thermal cycling between 350 C and 100 C; the specimen is freed to expand and contract. Two semi-circular notches (0,1 mm depth and 4 mm length) have been machined on the surface of the specimen. A series of interrupted tests has been carried out to characterize and quantify the crack growth in depth and surface of the pre-existing crack. Next, a three-dimensional crack growth simulation has been implemented in ABAQUS. Automation using Python was used to simulate the propagation of a crack under thermal cycling, with re-meshing at crack front after each calculation step. No assumption has been taken on the crack front during the crack propagation. A comparison with test results showed very good agreement on the evolution of crack front shape and on the kinetics of propagation on the edge and the heart of pre-existing crack. An analytical approach was also developed based on the calculation of stress intensity factors (SIC). A two-dimensional approach was first introduced enabling us to better understand the influence of various thermal and geometric parameters. Finally, a three dimensional approach, with an elliptical assumption crack shape during the propagation, leading to a prediction of crack growth on the surface and in depth which is very similar to that obtained numerically, but with computational time much lower. (author)

Penetration of gold nanoparticles across the stratum corneum layer of thick-Skin.

Science.gov (United States)

Raju, Gayathri; Katiyar, Neeraj; Vadukumpully, Sajini; Shankarappa, Sahadev A

2018-02-01

Transdermal particulate penetration across thick-skin, such as that of palms and sole, is particularly important for drug delivery for disorders such as small fiber neuropathies. Nanoparticle-based drug delivery across skin is believed to have much translational applications, but their penetration especially through thick-skin, is not clear. This study specifically investigates the effectiveness of gold nanoparticles (AuNPs) for thick-skin penetration, especially across the stratum corneum (SC) as a function of particle size. The thick-skinned hind-paw of rat was used to characterize depth and distribution of AuNPs of varying sizes, namely, 22±3, 105±11, and 186±20nm. Epidermal penetration of AuNPs was characterized both, in harvested skin from the hind-paw using a diffusion chamber, as well as in vivo. Harvested skin segments exposed to 22nm AuNPs for only 3h demonstrated higher penetration (pthick-skin allows nanoparticle penetration and acts as a depot for release of AuNPs into circulation long after the initial exposure has ceased. Copyright © 2017 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

Development and Applications of Time of Flight Neutron Depth Profiling

International Nuclear Information System (INIS)

Cady, Bingham; Unlu, Kenan

2005-01-01

The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. For example, the subtle differences in spatial distribution and composition of many chemical species in the near surface region and across interfacial boundaries can significantly alter the electronic and optical properties of materials. A number of analytical techniques for depth profiling have been developed during the last two decades. neutron Depth Profiling (NDP) is one of the leading analytical techniques. The NDP is a nondestructive near surface technique that utilizes thermal/cold neutron beam to measure the concentration of specific light elements versus their depth in materials. The depth is obtained from the energy loss of protons, alphas or recoil atoms in substrate materials. Since the charged particle energy determination using surface barrier detector is used for NDP, the depth resolution is highly dependent on the detectors an d detection instruments. The depth resolutions of a few tens of nm are achieved with available NDP facilities in the world. However, the performance of NDP needs to be improved in order to obtain a few A depth resolutions

The Superficial Dermis May Initiate Keloid Formation: Histological Analysis of the Keloid Dermis at Different Depths

Directory of Open Access Journals (Sweden)

Hu Jiao

2017-11-01

Full Text Available Several studies have reported on certain aspects of the characteristics of different sites within a keloid lesion, but detailed studies on the keloid dermis at different depths within a keloid lesion are scarce. The aim of this study was to investigate the histology of the keloid dermis at different depths. This study included 19 keloid tissue samples that were collected from 19 patients and 19 normal skin samples, which were harvested from subjects without keloids or hypertrophic scar. Samples were studied by light microscopy using routine hematoxylin and eosin histochemical staining, and immunohistochemistry to detect CD20-positive B-lymphocytes and CD3-positive T-lymphocytes. Sirius Red histochemical staining was used to determine the type of collagen in keloid tissue and normal skin samples. The migratory properties of fibroblasts within the keloid dermis at different depths was compared, using an in vitro migration assay. The findings of this study showed that although the papillary and reticular dermis could be clearly distinguished in normal skin, three tissue layers were identified in the keloid dermis. The superficial dermis of keloid was characterized by active fibroblasts and lymphocytes; the middle dermis contained dense extracellular matrix (ECM with large numbers fibroblasts, and the deep dermis was poorly cellular and characterized by hyalinized collagen bundles. In the keloid samples, from the superficial to the deep dermis, type I collagen increased and type III collagen decreased, and fibroblasts from the superficial dermis of the keloid were found to migrate more rapidly. In conclusion, the findings of this study showed that different depths within the keloid dermis displayed different biological features. The superficial dermis may initiate keloid formation, in which layer intralesional injection of pharmaceuticals and other treatments should be performed for keloid.

Human transient response under local thermal stimulation

Directory of Open Access Journals (Sweden)

Wang Lijuan

2017-01-01

Full Text Available Human body can operate physiological thermoregulation system when it is exposed to cold or hot environment. Whether it can do the same work when a local part of body is stimulated by different temperatures? The objective of this paper is to prove it. Twelve subjects are recruited to participate in this experiment. After stabilizing in a comfort environment, their palms are stimulated by a pouch of 39, 36, 33, 30, and 27°C. Subject’s skin temperature, heart rate, heat flux of skin, and thermal sensation are recorded. The results indicate that when local part is suffering from harsh temperature, the whole body is doing physiological thermoregulation. Besides, when the local part is stimulated by high temperature and its thermal sensation is warm, the thermal sensation of whole body can be neutral. What is more, human body is more sensitive to cool stimulation than to warm one. The conclusions are significant to reveal and make full use of physiological thermoregulation.

Semi-automated algorithm for localization of dermal/epidermal junction in reflectance confocal microscopy images of human skin

Science.gov (United States)

Kurugol, Sila; Dy, Jennifer G.; Rajadhyaksha, Milind; Gossage, Kirk W.; Weissmann, Jesse; Brooks, Dana H.

2011-03-01

The examination of the dermis/epidermis junction (DEJ) is clinically important for skin cancer diagnosis. Reflectance confocal microscopy (RCM) is an emerging tool for detection of skin cancers in vivo. However, visual localization of the DEJ in RCM images, with high accuracy and repeatability, is challenging, especially in fair skin, due to low contrast, heterogeneous structure and high inter- and intra-subject variability. We recently proposed a semi-automated algorithm to localize the DEJ in z-stacks of RCM images of fair skin, based on feature segmentation and classification. Here we extend the algorithm to dark skin. The extended algorithm first decides the skin type and then applies the appropriate DEJ localization method. In dark skin, strong backscatter from the pigment melanin causes the basal cells above the DEJ to appear with high contrast. To locate those high contrast regions, the algorithm operates on small tiles (regions) and finds the peaks of the smoothed average intensity depth profile of each tile. However, for some tiles, due to heterogeneity, multiple peaks in the depth profile exist and the strongest peak might not be the basal layer peak. To select the correct peak, basal cells are represented with a vector of texture features. The peak with most similar features to this feature vector is selected. The results show that the algorithm detected the skin types correctly for all 17 stacks tested (8 fair, 9 dark). The DEJ detection algorithm achieved an average distance from the ground truth DEJ surface of around 4.7μm for dark skin and around 7-14μm for fair skin.

Evaluation of Elastin/Collagen Content in Human Dermis in-Vivo by Multiphoton Tomography—Variation with Depth and Correlation with Aging

Directory of Open Access Journals (Sweden)

Jean-Christophe Pittet

2014-08-01

Full Text Available The aim of this study was to evaluate the influence of the depth of the dermis on the measured collagen and elastin levels and to establish the correlation between the amount of these two extracellular matrix (ECM components and age. Multiphoton Microscopy (MPM that measures the autofluorescence (AF and second harmonic generation (SHG was used to quantify the levels of elastin and collagen and to determine the SAAID (SHG-to-AF Aging Index of Dermis at two different skin depths. A 50 MHz ultrasound scanner was used for the calculation of the Sub Epidermal Non Echogenic Band (SENEB. The measurements of the skin mechanical properties were done with a cutometer. All measurements were performed on two groups of 30 healthy female volunteers. The MPM showed a decrease of the quantity of collagen and elastin as a function of depth of the dermis as well as age. The SAAID was lower for the older skin in the deeper dermis. Ultrasound imaging revealed a significant decrease of SENEB as a function of aging. The mechanical properties confirmed a loss of cutaneous elasticity and firmness. Although multiphoton microscopy is a powerful technique to study the characteristics of the dermis and its age-related damage, the location of the measurements (depth remains very important for the validation of these variations. These variations do not seem to be homogeneous according to the part of the dermis that is studied.

Estimation of deep, eye lens and skin doses for high energy electron beams for dosimetry and protection purpose

International Nuclear Information System (INIS)

Reena Kumari; Rakesh, R.B.

2018-01-01

In the radiological protection especially for individual as well as area monitoring, it is generally considered that beta sources deposit skin and eye lens doses only as they do not have enough energy for depositing doses at 10 mm depth. Also, the skin and eye lens doses differ substantially due to attenuation of beta particles at 0.07 mm (skin) and 3 mm (eye lens) depths and the surface doses are always greater than eye lens doses even for the highest energy beta source used in brachytherapy applications. However, worldwide increase in the use of high energy electron accelerators, new challenges are being posed for radiological protection and the operational quantities defined previously by ICRU are being reviewed. In view of these developments, studies have been performed for different electron beams in the energy range from (4 - 20) MeV generated using a medical linear accelerator. The aim of the study is to measure doses deposited at various depths as defined by ICRU 39 for individual and area monitoring purposes

Skin dose from radiotherapy X-ray beams: the influence of energy

International Nuclear Information System (INIS)

Butson, M.J.; Metcalfe, P.E.; University of Wollongong, Wollongong, NSW; Mathur, J.N.

1997-01-01

Skin-sparing properties of megavoltage photon beams are compromised by electron contamination. Higher energy beams do not necessarily produce lower surface and basal cell layer doses due to this electron contamination. For a 5x5 cm field size the surface doses for 6 MVp and 18 M)p X-ray beams are 10% and 7% of their respective maxima. However, at a field size of 40 x 40cm the percentage surface dose is 42% for both 6 MVp and 18 MVp beams. The introduction of beam modifying devices such as block trays can further reduce the skin-sparing advantages of high energy photon beams. Using a 10 mm perspex block tray, the surface doses for 6 MVp and 18 MVp beams with a 5 x 5 cm field size are 10% and 8%, respectively. At 40 x 40cm, surface doses are 61% and 63% for 6 MVp and 18 MVp beams, respectively. This trend is followed at the basal cell layer depth. At a depth of 1 mm, 18 MVp beam doses are always at least 5% smaller than 6 MVp doses for the same depth at all field sizes when normalized to their respective Dmax values. Results have shown that higher energy photon beams produce a negligible reduction of the delivered dose to the basal cell layer (0.1 mm). Only a small increase in skin sparing is seen at the dermal layer (1 mm), which can be negated by the increased exit dose from an opposing field. (authors)

Clinical use of carbon-loaded thermoluminescent dosimeters for skin dose determination

International Nuclear Information System (INIS)

Ostwald, Patricia M.; Kron, Tomas; Hamilton, Christopher S.; Denham, James W.

1995-01-01

Purpose: Carbon-loaded thermoluminescent dosimeters (TLDs) are designed for surface/skin dose measurements. Following 4 years in clinical use at the Mater Hospital, the accuracy and clinical usefulness of the carbon-loaded TLDs was assessed. Methods and Materials: Teflon-based carbon-loaded lithium fluoride (LiF) disks with a diameter of 13 mm were used in the present study. The TLDs were compared with ion chamber readings and TLD extrapolation to determine the effective depth of the TLD measurement. In vivo measurements were made on patients receiving open-field treatments to the chest, abdomen, and groin. Skin entry dose or entry and exit dose were assessed in comparison with doses estimated from phantom measurements. Results: The effective depth of measurement in a 6 MV therapeutic x-ray beam was found to be about 0.10 mm using TLD extrapolation as a comparison. Entrance surface dose measurements made on a solid water phantom agreed well with ion chamber and TLD extrapolation measurements, and black TLDs provide a more accurate exit dose than the other methods. Under clinical conditions, the black TLDs have an accuracy of ± 5% (± 2 SD). The dose predicted from black TLD readings correlate with observed skin reactions as assessed with reflectance spectroscopy. Conclusion: In vivo dosimetry with carbon-loaded TLDs proved to be a useful tool in assessing the dose delivered to the basal cell layer in the skin of patients undergoing radiotherapy

Tenskinmetric Evaluation of Surface Energy Changes in Adult Skin: Evidence from 834 Normal Subjects Monitored in Controlled Conditions

Directory of Open Access Journals (Sweden)

Camilla Dal Bosco

2014-03-01

Full Text Available To evaluate the influence of the skin aging critical level on the adult skin epidermal functional state, an improved analytical method based on the skin surface energetic measurement (TVS modeling was developed. Tenskinmetric measurements were carried out non-invasively in controlled conditions by contact angle method using only a water-drop as reference standard liquid. Adult skin was monitored by TVS Observatory according to a specific and controlled thermal protocol (Camianta protocol in use at the interconnected “Mamma Margherita Terme spa” of Terme Euganee. From June to November 2013, the surface free energy and the epidermal hydration level of adult skin were evaluated on arrival of 265 male and 569 female adult volunteers (51–90 years of age and when they departed 2 weeks later. Sensitive measurements were carried out at 0.1 mN/m. High test compliance was obtained (93.2% of all guests. Very interesting results are obtained. The high sensitivity and discrimination power of tenskinmetry combined with a thermal Camianta protocol demonstrate the possibility to evaluate at baseline level the surface energetic changes and the skin reactivity which occurs on adult skin.

Thermal skin damage and mobile phone use

OpenAIRE

Elabbassi , Elmountacer-Billah; De Seze , René

2005-01-01

International audience; Mobile phone "cell phone" use has dramatically increased over th last decade, but doubts remain over its safety. Epidemiological investigation of mobile phone (MP) users reported symptoms of discomfort feeling, warmth behind/around or on the ear and heat sensation of the cheek. These symptoms may be due to thermal insulation, conduction of the heat produced in the phone by the battery currents and running of the radiofrequency (RF) electronic circuits, and electromagne...

Depth profiling of hydrogen in ferritic/martensitic steels by means of a tritium imaging plate technique

International Nuclear Information System (INIS)

Otsuka, Teppei; Tanabe, Tetsuo

2013-01-01

Highlights: ► We applied a tritium imaging plate technique to depth profiling of hydrogen in bulk. ► Changes of hydrogen depth profiles in the steel by thermal annealing were examined. ► We proposed a release model of plasma-loaded hydrogen in the steel. ► Hydrogen is trapped at trapping sites newly developed by plasma loading. ► Hydrogen is also trapped at surface oxides and hardly desorbed by thermal annealing. -- Abstract: In order to understand how hydrogen loaded by plasma in F82H is removed by annealing at elevated temperatures in vacuum, depth profiles of plasma-loaded hydrogen were examined by means of a tritium imaging plate technique. Owing to large hydrogen diffusion coefficients in F82H, the plasma-loaded hydrogen easily penetrates into a deeper region becoming solute hydrogen and desorbs by thermal annealing in vacuum. However the plasma-loading creates new hydrogen trapping sites having larger trapping energy than that for the intrinsic sites beyond the projected range of the loaded hydrogen. Some surface oxides also trap an appreciable amount of hydrogen which is more difficult to remove by the thermal annealing

Factors of skin decontamination as derived from experimental studies

International Nuclear Information System (INIS)

Pratzel, H.G.

1992-01-01

The processes occuring during radioactive contamination of the skin are reminiscent of those observed in connection with skin penetration by drugs. Explained are the laws determining the penetration of substances through the skin surface, their spreading between the corneocystes into the deeper layers of the stratum corneum and their final concentrations, the decrease of which with the depth of the corneal layer can be described by an exponential curve. The extent to which the penetrating substances are transferred from the solvent to the corneal layer's lipid phase depends on their relative solubility. The intercellular lipid layer in the lower third of the stratum corneum creates the greatest obstacle to permeation through the skin. The lipid content in this part of the corneal layer is seen to be inversely proportional to the degree of natural barrier dysfunction and, thus, to permeation. For measurements of skin permeation, experiments were performed in young pigs using aqueous radioactive solutions. Part of the substances penetrated into the organism through the follicles, where the corneal layer is more permeable. In cases of very hairy skin the amount of substance deposited as a result of additional follicle penetration is seen to be higher. The greatest proportion of radioactivity by far is taken up into the stratum corneum, while only little is seen to reach the follicles and even less the deeper layers of the skin. Decontamination of the skin cannot be carried out for areas beyond the boundary of the corneal layer. (orig./HP) [de

Evaluation of transdermal delivery of nanoemulsions in ex vivo porcine skin using two-photon microscopy and confocal laser-scanning microscopy

Science.gov (United States)

Choi, Sanghoon; Kim, Jin Woong; Lee, Yong Joong; Delmas, Thomas; Kim, Changhwan; Park, Soyeun; Lee, Ho

2014-10-01

This study experimentally evaluates the self-targeting ability of asiaticoside-loaded nanoemulsions compared with nontargeted nanoemulsions in ex vivo experiments with porcine skin samples. Homebuilt two-photon and confocal laser-scanning microscopes were employed to noninvasively examine the transdermal delivery of two distinct nanoemulsions. Prior to the application of nanoemulsions, we noninvasively observed the morphology of porcine skin using two-photon microscopy. We have successfully visualized the distributions of the targeted and nontargeted nanoemulsions absorbed into the porcine skin samples. Asiaticoside-loaded nanoemulsions showed an improved ex vivo transdermal delivery through the stratum corneum compared with nonloaded nanoemulsions. As a secondary measure, nanoemulsions-applied samples were sliced in the depth direction with a surgical knife in order to obtain the complete depth-direction distribution profile of Nile red fluorescence. XZ images demonstrated that asiaticoside-loaded nanoemulsion penetrated deeper into the skin compared with nontargeted nanoemulsions. The basal layer boundary is clearly visible in the case of the asiaticoside-loaded skin sample. These results reaffirm the feasibility of using self-targeting ligands to improve permeation through the skin barrier for cosmetics and topical drug applications.

Development of ultraviolet- and visible-light one-shot spectral domain optical coherence tomography and in situ measurements of human skin

Science.gov (United States)

Hirayama, Heijiro; Nakamura, Sohichiro

2015-07-01

We have developed ultraviolet (UV)- and visible-light one-shot spectral domain (SD) optical coherence tomography (OCT) that enables in situ imaging of human skin with an arbitrary wavelength in the UV-visible-light region (370-800 nm). We alleviated the computational burden for each color OCT image by physically dispersing the irradiating light with a color filter. The system consists of SD-OCT with multicylindrical lenses; thus, mechanical scanning of the mirror or stage is unnecessary to obtain an OCT image. Therefore, only a few dozens of milliseconds are necessary to obtain single-image data. We acquired OCT images of one subject's skin in vivo and of a skin excision ex vivo for red (R, 650±20 nm), green (G, 550±20 nm), blue (B, 450±20 nm), and UV (397±5 nm) light. In the visible-light spectrum, R light penetrated the skin and was reflected at a lower depth than G or B light. On the skin excision, we demonstrated that UV light reached the dermal layer. We anticipated that basic knowledge about the spectral properties of human skin in the depth direction could be acquired with this system.

Advanced thermal management materials

CERN Document Server

Jiang, Guosheng; Kuang, Ken

2012-01-01

""Advanced Thermal Management Materials"" provides a comprehensive and hands-on treatise on the importance of thermal packaging in high performance systems. These systems, ranging from active electronically-scanned radar arrays to web servers, require components that can dissipate heat efficiently. This requires materials capable of dissipating heat and maintaining compatibility with the packaging and dye. Its coverage includes all aspects of thermal management materials, both traditional and non-traditional, with an emphasis on metal based materials. An in-depth discussion of properties and m

Revision Vaginoplasty: A Comparison of Surgical Outcomes of Laparoscopic Intestinal versus Perineal Full-Thickness Skin Graft Vaginoplasty.

Science.gov (United States)

Van der Sluis, Wouter B; Bouman, Mark-Bram; Buncamper, Marlon E; Mullender, Margriet G; Meijerink, Wilhelmus J

2016-10-01

Vaginal (re)construction can greatly improve the quality of life of indicated patients. If primary vaginoplasty fails, multiple surgical approaches exist for revision. The authors compared surgical results of laparoscopic intestinal versus full-thickness skin graft revision vaginoplasty. A retrospective chart review of patients who underwent revision vaginoplasty at the authors' institution was conducted. Patient demographics, surgical characteristics, complications, hospitalization, reoperations, and neovaginal depth for both surgical techniques were recorded and compared. The authors studied a consecutive series of 50 transgender and three biological women who underwent revision vaginoplasty, of which 21 were laparoscopic intestinal and 32 were perineal full-thickness skin graft vaginoplasties, with a median clinical follow-up of 3.2 years (range, 0.5 to 19.7 years). Patient demographics did not differ significantly. There was no mortality. Two intraoperative rectal perforations (10 percent) occurred in the intestinal group versus six (19 percent) in the full-thickness skin graft group. Operative time was shorter for the full-thickness skin graft vaginoplasty group (131 ± 35 minutes versus 191 ± 45 minutes; p skin graft (81 percent) vaginoplasty procedures. A deeper neovagina was achieved with intestinal vaginoplasty (15.9 ± 1.4 cm versus 12.5 ± 2.8 cm; p skin graft vaginoplasty can be used as secondary vaginal reconstruction. Intraoperative and postoperative complications do not differ significantly, but rectal perforation was more prevalent in the full-thickness skin graft vaginoplasty group. Although the operative time of laparoscopic intestinal vaginoplasty is longer, adequate neovaginal depth was more frequently achieved than in secondary perineal full-thickness skin graft vaginoplasty. Therapeutic, III.

Evaluate depth of field limits of fixed focus lens arrangements in thermal infrared

Science.gov (United States)

Schuster, Norbert

2016-05-01

More and more modern thermal imaging systems use uncooled detectors. High volume applications work with detectors that have a reduced pixel count (typically between 200x150 and 640x480). This reduces the usefulness of modern image treatment procedures such as wave front coding. On the other hand, uncooled detectors demand lenses with fast fnumbers, near f/1.0, which reduces the expected Depth of Field (DoF). What are the limits on resolution if the target changes distance to the camera system? The desire to implement lens arrangements without a focusing mechanism demands a deeper quantification of the DoF problem. A new approach avoids the classic "accepted image blur circle" and quantifies the expected DoF by the Through Focus MTF of the lens. This function is defined for a certain spatial frequency that provides a straightforward relation to the pixel pitch of imaging device. A certain minimum MTF-level is necessary so that the complete thermal imaging system can realize its basic functions, such as recognition or detection of specified targets. Very often, this technical tradeoff is approved with a certain lens. But what is the impact of changing the lens for one with a different focal length? Narrow field lenses, which give more details of targets in longer distances, tighten the DoF problem. A first orientation is given by the hyperfocal distance. It depends in a square relation on the focal length and in a linear relation on the through focus MTF of the lens. The analysis of these relations shows the contradicting requirements between higher thermal and spatial resolution, faster f-number and desired DoF. Furthermore, the hyperfocal distance defines the DoF-borders. Their relation between is such as the first order imaging formulas. A calculation methodology will be presented to transfer DoF-results from an approved combination lens and camera to another lens in combination with the initial camera. Necessary input for this prediction is the accepted DoF of

In-vitro investigations of skin closure using diode laser and protein solder containing gold nano shells

International Nuclear Information System (INIS)

Nourbakhsh, M. S.; Etrati Khosroshahi, M.

2011-01-01

Laser tissue soldering is a new technique for repair of various tissues including the skin, liver, articular cartilage and nerves and is a promising alternative to suture. To overcome the problems of thermal damage to surrounding tissues and low laser penetration depth, some exogenous chromophores such as gold nano shells, a new class of nanoparticles consisting of a dielectric core surrounded by a thin metal shell, are used. The aims of this study were to use two different concentrations of gold nano shells as the exogenous material for skin tissue soldering and also to examine the effects of laser soldering parameters on the properties of the repaired skin. Material and Methods: Two mixtures of albumin solder and different concentrations of gold nano shells were prepared. A full thickness incision of 2*20 mm 2 was made on the surface and after placing 50 μ1 of the solder mixture on the incision, an 810 nm diode laser was used to irradiate it at different power densities. The changes of tensile strength, σt, due to temperature rise, number of scan (Ns), and scan velocity (Vs) were investigated. Results: The results showed that the tensile strength of the repaired skin increased with increasing irradiance for both gold nano shell concentrations. In addition, at constant laser irradiance (I), the tensile strength of the repaired incision increased with increasing Ns and decreasing Vs. In our case, this corresponded to σt = 1610 g/cm 2 at I ∼ 60 W cm-2, T ∼ 65 d egree C , Ns = 10 and Vs = 0.2 mms-1. Discussion and Conclusion: Gold nano shells can be used as an indocyanine green dye alterative for laser tissue soldering. Although by increasing the laser power density, the tensile strength of the repaired skin increases, an optimum power density must be considered due to the resulting increase in tissue temperature.

A synchrotron X-ray diffraction deconvolution method for the measurement of residual stress in thermal barrier coatings as a function of depth.

Science.gov (United States)

Li, C; Jacques, S D M; Chen, Y; Daisenberger, D; Xiao, P; Markocsan, N; Nylen, P; Cernik, R J

2016-12-01

The average residual stress distribution as a function of depth in an air plasma-sprayed yttria stabilized zirconia top coat used in thermal barrier coating (TBC) systems was measured using synchrotron radiation X-ray diffraction in reflection geometry on station I15 at Diamond Light Source, UK, employing a series of incidence angles. The stress values were calculated from data deconvoluted from diffraction patterns collected at increasing depths. The stress was found to be compressive through the thickness of the TBC and a fluctuation in the trend of the stress profile was indicated in some samples. Typically this fluctuation was observed to increase from the surface to the middle of the coating, decrease a little and then increase again towards the interface. The stress at the interface region was observed to be around 300 MPa, which agrees well with the reported values. The trend of the observed residual stress was found to be related to the crack distribution in the samples, in particular a large crack propagating from the middle of the coating. The method shows promise for the development of a nondestructive test for as-manufactured samples.

Safety Evaluation of Cosmetic Ingredients Regarding Their Skin Sensitization Potential

Directory of Open Access Journals (Sweden)

Winfried Steiling

2016-03-01

Full Text Available Up to today, product safety evaluation in the EU is predominantly based on data/information on their individual ingredients. Consequently, the quality and reliability of individual ingredient data is of vital interest. In this context, the knowledge about skin sensitization potential is an explicit need for both hazard and risk assessment. Proper skin sensitization data of the individual chemicals is essential, especially when dermal contact is intended, like for cosmetics. In some cases, e.g., in the presence of irritating chemicals, the combination of individual ingredients may also need to be evaluated to cover possible mixture effects. Today, it seems unlikely or even impossible that skin sensitization in humans can be adequately described by a single test result or even by a simple combination of a few data points (in vivo or in vitro. It is becoming evident that a set of data (including human data and market data and knowledge about the ingredient’s specific sensitizing potency needs to be taken into account to enable a reliable assessment of skin sensitization. A more in-depth understanding on mechanistic details of the Adverse-Outcome-Pathway of skin sensitization could contribute key data for a robust conclusion on skin sensitization.

Functional and physiological characteristics of the aging skin.

Science.gov (United States)

Farage, Miranda A; Miller, Kenneth W; Elsner, Peter; Maibach, Howard I

2008-06-01

As life expectancy in the U.S. increases - and with it the proportion of the aged in the population - appropriate care of elderly skin becomes a medical concern of increasing importance. As skin ages, the intrinsic structural changes that are a natural consequence of passing time are inevitably followed by subsequent physiological changes that affect the skin's ability to function as the interface between internal and external environments. The pH of the skin surface increases with age, increasing its susceptibility to infection. Neurosensory perception of superficial pain is diminished both in intensity and speed of perception (increasing the risk of thermal injury); deep tissue pain, however, may be enhanced. A decline in lipid content as the skin ages inhibits the permeability of nonlipophilic compounds, reducing the efficacy of some topical medications. Allergic and irritant reactions are blunted, as is the inflammatory response, compromising the ability of the aged skin to affect wound repair. These functional impairments (although a predictable consequence of intrinsic structural changes) have the potential to cause significant morbidity in the elderly patient and may, as well, be greatly exacerbated by extrinsic factors like photodamage. As numbers of the elderly increase, medical as well as cosmetic dermatological interventions will be necessary to optimize the quality of life for this segment of the population.

Vascular thermal adaptation in tumors and normal tissue in rats

International Nuclear Information System (INIS)

Nah, Byung Sik; Choi, Ihl-Bohng; Oh, Won Young; Osborn, James L.; Song, Chang W.

1996-01-01

Purpose: The vascular thermal adaptation in the R3230 adenocarcinoma, skin and muscle in the legs of Fischer rats was studied. Methods and Materials: The legs of Fischer rats bearing the R3230 AC adenocarcinoma (subcutaneously) were heated once or twice with a water bath, and the blood flow in the tumor, skin and muscle of the legs was measured with the radioactive microsphere method. Results: The blood flow in control R3230 AC tumors was 23.9 ml/100 g/min. The tumor blood flow increased about 1.5 times in 30 min and then markedly decreased upon heating at 44.5 deg. C for 90 min. In the tumors preheated 16 h earlier at 42.5 deg. C for 60 min, reheating at 44.5 deg. C increased the tumor blood flow by 2.5-fold in 30 min. Contrary to the decline in blood flow following an initial increase during the 44.5 deg. C heating without preheating, the tumor blood flow remained elevated throughout the 90 min reheating at 44.5 deg. C. These results indicated that thermal adaptation or thermotolerance developed in the tumor vasculatures after the preheating at 42.5 deg. C for 60 min. The magnitude of vascular thermal adaptation in the tumors 24 h and 48 h after the preheating, as judged from the changes in blood flow, were smaller than that 16 h after the preheating. Heating at 42.5 deg. C for 60 min induced vascular thermal adaptation also in the skin and muscle, which peaked in 48 h and 24 h, respectively, after the heating. Conclusion: Heating at 42.5 deg. C for 1 h induced vascular thermal adaptation in the R3230 AC tumor, skin, and muscle of rats that peaked 16-48 h after the heating. When the tumor blood vessels were thermally adapted, the tumor blood flow increased upon heating at temperatures that would otherwise reduce the tumor blood flow. Such an increase in tumor blood flow may hinder raising the tumor temperature while it may increase tumor oxygenation.

A study on the utilization of hyper-thermal neutrons for neutron capture therapy

International Nuclear Information System (INIS)

Sakurai, Yoshinori; Kobayashi, Tooru; Kanda, Keiji

1993-01-01

The utilization of hyper-thermal neutrons, which have an energy spectrum of a Maxwellian distribution of a higher temperature than the room temperature of 300 K, was studied in order to improve the thermal neutron flux distribution at the deeper part in a living body for neutron capture therapy. Simulation calculations were carried out using MCNP-V3 in order to confirm the characteristics of hyper-thermal neutrons, i.e., (1) depth dependence of neutron energy spectrum, and (2) depth distribution of the reaction rate in a water phantom for materials with 1/v neutron absorption. It is confirmed that the hyper-thermal neutron irradiation can improve the thermal neutron flux distribution in the deeper and wider area in a living body compared with the thermal neutron irradiation. Practically, by the incidence of the hyper-thermal neutrons with a 3000 K Maxwellian distribution, the thermal neutron flux at 5 cm depth can be given about four times larger than by the incidence of the thermal neutrons of 300 K. (author)

The spectrum of laser skin resurfacing: nonablative, fractional, and ablative laser resurfacing.

Science.gov (United States)

Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

2008-05-01

The drive to attain cosmetic facial enhancement with minimal risk and rapid recovery has inspired the field of nonsurgical skin rejuvenation. Laser resurfacing was introduced in the 1980s with continuous wave carbon dioxide (CO(2)) lasers; however, because of a high rate of side effects, including scarring, short-pulse, high-peak power, and rapidly scanned, focused-beam CO(2) lasers and normal-mode erbium-doped yttrium aluminium garnet lasers were developed, which remove skin in a precisely controlled manner. The prolonged 2-week recovery time and small but significant complication risk prompted the development of non-ablative and, more recently, fractional resurfacing in order to minimize risk and shorten recovery times. Nonablative resurfacing produces dermal thermal injury to improve rhytides and photodamage while preserving the epidermis. Fractional resurfacing thermally ablates microscopic columns of epidermal and dermal tissue in regularly spaced arrays over a fraction of the skin surface. This intermediate approach increases efficacy as compared to nonablative resurfacing, but with faster recovery as compared to ablative resurfacing. Neither nonablative nor fractional resurfacing produces results comparable to ablative laser skin resurfacing, but both have become much more popular than the latter because the risks of treatment are limited in the face of acceptable improvement. At the completion of this learning activity, participants should be familiar with the spectrum of lasers and light technologies available for skin resurfacing, published studies of safety and efficacy, indications, methodologies, side effects, complications, and management.

Hair bleaching and skin burning

OpenAIRE

Forster, K.; Lingitz, R.; Prattes, G.; Schneider, G.; Sutter, S.; Schintler, M.; Trop, M.

2012-01-01

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.

Bioinspired microneedle insertion for deep and precise skin penetration with low force: Why the application of mechanophysical stimuli should be considered.

Science.gov (United States)

Kim, Jonghun; Park, Sungmin; Nam, Gyungmok; Choi, Young; Woo, Seungpyo; Yoon, Sang-Hee

2018-02-01

A mosquito is known to precisely and easily insert its proboscis to the human skin by pressing down a labium and vibrating a fascicle bundle. Its advanced skin-piercing mechanisms indicate that skin resistance to the insertion of needle-like objects can be changed by the application of mechanophysical stimuli. Here, we characterize the effect of the application of mechanophysical stimuli on skin resistance to microneedle insertion to find clues for inserting a microneedle in a deep and precise fashion with low force. Microneedles with a diameter of 60-140µm are inserted at a velocity of 0.1-2.0mm/s to full-thickness porcine skins while either uniaxial/equibiaxial stretch of 0-20% or mechanical vibration at a frequency of 1 to 1000Hz and an amplitude of 1-10µm is applied to the skins as static or dynamic mechanophysical stimulus, respectively. The values of force and depth at two events of skin puncture and maximum penetration are measured to explore changes in skin resistance induced by the application of external stimuli. The static mechanophysical stimulus applied to the skin mainly affects the precision of microneedle insertion; the application of dynamic mechanophysical stimulus controls the value and deviation of skin resistance to microneedle insertion. The application of mechanophysical stimuli, inspired from a mosquito, therefore allows a microneedle to be deeply and easily inserted to the skin in a controlled way. The findings will have broad impacts on microneedle-mediated applications and lead to an in-depth understanding of skin biomechanics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Source to Skin Distance (SSD) Characteristics from Varian CX Linear Accelerator

Science.gov (United States)

Bahari Nurdin, Wira; Purnomo, Aji; Dewang, Syamsir

2018-03-01

This study aims to describe the characteristics of the source to skin distance (SSD) of Varian CX linear accelerator (LINAC) using the X-ray beam of 6 MV and 10 MV. The variation of the source to the SSD are 90, 100 and 110 cms; the depth of the water phantom used are 5, 10, 15, 20, and 25 cms, respectively. The depth of the water phantom was created for analysis of percentage depth dose (PDD) and profile dose. It can be concluded from the tests that from the measured SSD, SSD of 110 cm with the depth water phantom of 20-25 cm for energy beam of 6 MV and at all levels of depth for 10 MV energy corresponding tolerance limits to be used in clinical radiotherapy. For the SSD 90 and 100, the values beam symmetry and flatness obtained slightly beyond the limits of tolerance.

Unique Presentation of Orf Virus Infection in a Thermal-Burn Patient After Receiving an Autologous Skin Graft.

Science.gov (United States)

Hsu, Christopher H; Rokni, Ghasem Rahmatpour; Aghazadeh, Nessa; Brinster, Nooshin; Li, Yu; Muehlenbachs, Atis; Goldsmith, Cynthia S; Zhao, Hui; Petersen, Brett; McCollum, Andrea M; Reynolds, Mary G

2016-10-15

We describe a burn patient who developed skin lesions on her skin-graft harvest and skin-graft recipient (burn) sites. Orf virus infection was confirmed by a combination of diagnostic assays, including molecular tests, immunohistochemical analysis, pathologic analysis, and electron microscopy. DNA sequence analysis grouped this orf virus isolate among isolates from India. Although no definitive source of infection was determined from this case, this is the first reported case of orf virus infection in a skin graft harvest. Skin graft recipients with exposures to animals may be at risk for this viral infection. Published by Oxford University Press for the Infectious Diseases Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

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

Science.gov (United States)

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

2012-07-01

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

Steam generator thermal-hydraulics

International Nuclear Information System (INIS)

Inch, W.W.; Scott, D.A.; Carver, M.B.

1980-01-01

This paper discusses a code for detailed numerical modelling of steam generator thermal-hydraulics, and describes related experimental programs designed to promote in-depth understanding of three-dimensional two-phase flow. (auth)

Thermal Performance of a Scramjet Combustor Operating at Mach 5.6 Flight Conditions

National Research Council Canada - National Science Library

Stouffer, Scott

1997-01-01

.... The objective of the thermal loads testing was to map the thermal and mechanical loads, including heat transfer, dynamic and static pressures, and skin friction in a scramjet combustor during direct...

The influence of corneocyte structure on the interpretation of permeation profiles of nanoparticles across skin

Energy Technology Data Exchange (ETDEWEB)

Pinheiro, T. [LFI, Instituto Tecnologico Nuclear, and Centro de Fisica Nuclear, Universidade Lisboa E.N. 10, 2685-953 Sacavem (Portugal)]. E-mail: murmur@itn.pt; Pallon, J. [Lund Institute of Technology, Physics Department, Lund University, Lund (Sweden)]. E-mail: Jan.Pallon@pixe.lth.se; Alves, L.C. [LFI, Instituto Tecnologico Nuclear, and Centro de Fisica Nuclear, Universidade Lisboa E.N. 10, 2685-953 Sacavem (Portugal)]. E-mail: lcalves@itn.pt; Verissimo, A. [LFI, Instituto Tecnologico Nuclear, and Centro de Fisica Nuclear, Universidade Lisboa E.N. 10, 2685-953 Sacavem (Portugal)]. E-mail: averissimo@vims.edu; Filipe, P. [Departamento Dermatologia, Hospital Sta. Maria, Lisbon (Portugal)]. E-mail: pfilipe@fm.ul.pt; Silva, J.N. [Departamento Dermatologia, Hospital Sta. Maria, Lisbon (Portugal)]. E-mail: maiasilva@fm.ul.pt; Silva, R. [Departamento Dermatologia, Hospital Sta. Maria, Lisbon (Portugal)]. E-mail: rpalminhas@netcabo.pt

2007-07-15

The permeability of skin to nanoparticles of titanium dioxide (TiO{sub 2}) used in sunscreens as a reflector of the UV wavelengths of sunlight, was examined using nuclear microscopy techniques. Special attention was given to the permeation characteristics of these nanoparticles across the outer layers of skin, the stratum corneum, in healthy and psoriatic skin condition. Aspects that may influence the interpretation of results such as sample preparation difficulties and skin condition were focused. Sample preparation can damage the integrity of the corneocyte layers inducing unwanted artefacts that may bias the evaluation of results. Irradiation conditions may also introduce distortions in the labile structures of human skin. Skin condition, such as loss of corneocyte cohesion occurring in psoriasis also influence the permeation profile of the nanoparticles. Weighing and accounting for these features in the examination of skin by nuclear microscopy is crucial to accurately assess the TiO{sub 2} nanoparticles permeation depth.

Ballistic Phonon Penetration Depth in Amorphous Silicon Dioxide.

Science.gov (United States)

Yang, Lin; Zhang, Qian; Cui, Zhiguang; Gerboth, Matthew; Zhao, Yang; Xu, Terry T; Walker, D Greg; Li, Deyu

2017-12-13

Thermal transport in amorphous silicon dioxide (a-SiO 2 ) is traditionally treated as random walks of vibrations owing to its greatly disordered structure, which results in a mean free path (MFP) approximately the same as the interatomic distance. However, this picture has been debated constantly and in view of the ubiquitous existence of thin a-SiO 2 layers in nanoelectronic devices, it is imperative to better understand this issue for precise thermal management of electronic devices. Different from the commonly used cross-plane measurement approaches, here we report on a study that explores the in-plane thermal conductivity of double silicon nanoribbons with a layer of a-SiO 2 sandwiched in-between. Through comparing the thermal conductivity of the double ribbon samples with that of corresponding single ribbons, we show that thermal phonons can ballistically penetrate through a-SiO 2 of up to 5 nm thick even at room temperature. Comprehensive examination of double ribbon samples with various oxide layer thicknesses and van der Waals bonding strengths allows for extraction of the average ballistic phonon penetration depth in a-SiO 2 . With solid experimental data demonstrating ballistic phonon transport through a-SiO 2 , this work should provide important insight into thermal management of electronic devices.

Skin graft fixation in severe burns: use of topical negative pressure.

Science.gov (United States)

Kamolz, L P; Lumenta, D B; Parvizi, D; Wiedner, M; Justich, I; Keck, M; Pfurtscheller, K; Schintler, M

2014-09-30

Over the last 50 years, the evolution of burn care has led to a significant decrease in mortality. The biggest impact on survival has been the change in the approach to burn surgery. Early excision and grafting has become a standard of care for the majority of patients with deep burns; the survival of a given patient suffering from major burns is invariably linked to the take rate and survival of skin grafts. The application of topical negative pressure (TNP) therapy devices has demonstrated improved graft take in comparison to conventional dressing methods alone. The aim of this study was to analyze the impact of TNP therapy on skin graft fixation in large burns. In all patients, we applied TNP dressings covering a %TBSA of >25. The following parameters were recorded and documented using BurnCase 3D: age, gender, %TBSA, burn depth, hospital length-of-stay, Baux score, survival, as well as duration and incidence of TNP dressings. After a burn depth adapted wound debridement, coverage was simultaneously performed using split-thickness skin grafts, which were fixed with staples and covered with fatty gauzes and TNP foam. The TNP foam was again fixed with staples to prevent displacement and finally covered with the supplied transparent adhesive film. A continuous subatmospheric pressure between 75-120 mm Hg was applied (VAC®, KCI, Vienna, Austria). The first dressing change was performed on day 4. Thirty-six out of 37 patients, suffering from full thickness burns, were discharged with complete wound closure; only one patient succumbed to their injuries. The overall skin graft take rate was over 95%. In conclusion, we consider that split thickness skin graft fixation by TNP is an efficient method in major burns, notably in areas with irregular wound surfaces or subject to movement (e.g. joint proximity), and is worth considering for the treatment of aged patients.

Variscan deformation along the Teisseyre-Tornquist Zone in SE Poland: Thick-skinned structural inheritance or thin-skinned thrusting?

Science.gov (United States)

Krzywiec, P.; Gągała, Ł.; Mazur, S.; Słonka, Ł.; Kufrasa, M.; Malinowski, M.; Pietsch, K.; Golonka, J.

2017-10-01

Recently acquired seismic reflection data provide better insight in the structural style of extensive sedimentary series overlying the SW slope of the East European Craton (EEC) in Poland. The two main seismic datasets - the POLCRUST-01 profile and PolandSPAN survey - yielded contrasting thick - and thin-skinned structural models for the same structural units in SE Poland. We reattempt an interpretation of the POLCRUST-01 profile using techniques of cross-section balancing and restoration aided by 2D forward seismic modelling. An outcome is the thin-skinned structural model is. This solution relies on a continuous top of the EEC crystalline basement well represented in the seismic data as well as on fragmentary, yet conclusive seismic geometries in shallow depth intervals proving the Ediacaran-Palaeozoic series to be thrust and folded. A Variscan (late Carboniferous) compressional regime is consequently invoked to explain thin-skinned structuring of the pre-Permian sedimentary pile and > 20 km of calculated shortening. We demonstrate an ambiguous nature of the top-basement irregularities previously used as indicators of basement-rooted vertical faulting. The tilt and abrupt increase of the top-basement taper under the thin-skinned belt are attributed to pre-Ordovician tectonic processes operating along the SW margin of the EEC. Post-rift subsidence and/or flexural loading giving rise to a broken foreland plate are invoked.

Effect of controlled laser microporation on drug transport kinetics into and across the skin.

Science.gov (United States)

Bachhav, Y G; Summer, S; Heinrich, A; Bragagna, T; Böhler, C; Kalia, Y N

2010-08-17

The objectives of this study were to investigate a novel laser microporation technology ( P.L.E.A.S.E. Painless Laser Epidermal System) and to determine the effect of pore number and depth on the rate and extent of drug delivery across the skin. In addition, the micropores were visualized by confocal laser scanning microscopy and histological studies were used to determine the effect of laser fluence (energy applied per unit area) on pore depth. Porcine ear skin was used as the membrane for both the pore characterization and drug transport studies. Confocal images in the XY-plane revealed that the pores were typically 150-200 microm in diameter. Histological sections confirmed that fluence could be used to effectively control pore depth - low energy application (4.53 and 13.59 J/cm(2)) resulted in selective removal of the stratum corneum (20-30 microm), intermediate energies (e.g., 22.65 J/cm(2)) produced pores that penetrated the viable epidermis (60-100 microm) and higher application energies created pores that reached the dermis (>150-200 microm). The effects of pore number and pore depth on molecular transport were quantified by comparing lidocaine delivery kinetics across intact and porated skin samples. After 24h, cumulative skin permeation of lidocaine with 0 (control), 150, 300, 450 and 900 pores was 107+/-46, 774+/-110, 1400+/-344, 1653+/-437 and 1811+/-642 microg/cm(2), respectively; there was no statistically significant difference between 300, 450 and 900 pore data - probably due to the effect of drug depletion since >50% of the applied dose was delivered. Importantly, increasing fluence did not produce a statistically significant increase in lidocaine permeation; after 24h, cumulative lidocaine permeation was 1180+/-448, 1350+/-445, 1240+/-483 and 1653+/-436 microg/cm(2) at fluences of 22.65, 45.3, 90.6 and 135.9 J/cm(2), respectively. Thus, shallow pores were equally effective in delivering lidocaine. Increasing lidocaine concentration in the

Quantitative evaluation of enhanced laser tattoo removal by skin optical clearing

Directory of Open Access Journals (Sweden)

Caihua Liu

2015-05-01

Full Text Available Lasers have been widely used for tattoo removal, but the limited light penetration depth caused by high skin scattering property restricts the therapeutic outcome of deep tattoo. Skin optical clearing method, by introducing optical clearing agent (OCA into skin, has shown some improvement in the effect of laser tattoo removal. In this study, the enhanced laser tattoo removal has been quantitatively assessed. OCA was applied to the skin of tattoo animal model and Q-switched Nd:YAG laser (1064 nm irradiation was used to remove the tattoo. The skin evaluation instrument (Mexameter probe, MPA580 was applied to measure the content of tattoo pigment before and after laser treatment, and then the clearance rate of pigment was calculated. Further, Monte Carlo (MC method was utilized to simulate the effect of skin optical clearing on light transmission in tattoo skin model. By comparing the pigment change of tattoo areas respectively treated with OCA plus laser and single laser, it was found that pigment clearance of the former tattoo area was increased by 1.5-fold. Further, the MC simulation verified that the reduced light scattering in skin could increase the effective dose of luminous flux reaching to the deep tattoo regions. It can be concluded from both experiment and theoretical simulations that skin optical clearing technique could improve the outcome of laser tattoo removal, which should be beneficial for clinical laser tattoo removal and other laser pigment elimination.

Hardness depth profiling of case hardened steels using a three-dimensional photothermal technique

International Nuclear Information System (INIS)

Qu Hong; Wang Chinhua; Guo Xinxin; Mandelis, Andreas