[Skin and Soft Tissue Infections Due to Corynebacterium ulcerans - Case Reports].

Science.gov (United States)

Jenssen, Christian; Schwede, Ilona; Neumann, Volker; Pietsch, Cristine; Handrick, Werner

2017-10-01

History and clinical findings  We report on three patients suffering from skin and soft tissue infections of the legs due to toxigenic Corynebacterium ulcerans strains. In all three patients, there was a predisposition due to chronic diseases. Three patients had domestic animals (cat, dog) in their households. Investigations and diagnosis  A mixed bacterial flora including Corynebacterium ulcerans was found in wound swab samples. Diphtheric toxin was produced by the Corynebacterium ulcerans strains in all three cases. Treatment and course  In all three patients, successful handling of the skin and soft tissue infections was possible by combining local treatment with antibiotics. Diphtheria antitoxin was not administered in any case. Conclusion  Based on a review of the recent literature pathogenesis, clinical symptoms and signs, diagnostics and therapy of skin and soft tissue infections due to Corynebacterium ulcerans are discussed. Corynebacterium ulcerans should be considered as a potential cause of severe skin and soft tissue infections. Occupational or domestic animal contacts should be evaluated. © Georg Thieme Verlag KG Stuttgart · New York.

Field enhancement due to anomalous skin effect inside a target

International Nuclear Information System (INIS)

Ma, G.; Tan, W.

1996-01-01

A new method based on Fourier transformation to study the skin effects is presented. Using this method, the field amplitude in plasma is represented in terms of electric conductivity, and the normal and anomalous skin effects are described through one formula by omitting the plasma dispersion or not. The results are in agreement with other publications [e.g., J. P. Matte and K. Aguenaou, Phys. Rev. A 45, 2558 (1992)] for equivalent parameters. But for deeper positions inside a target, which have not been studied by others, it is found that the field amplitude is considerably enhanced due to an anomalous skin effect, even for constant collision frequency. In addition, the skin absorptions and some calculations on an anomalous skin effect for different collision frequencies are also presented. copyright 1996 American Institute of Physics

The effects of titanium dioxide coatings on light-derived heating and transdermal heat transfer in bovine skin

Science.gov (United States)

Bartle, S. J.; Thomson, D. U.; Gehring, R.; van der Merwe, D.

2017-11-01

The effects of titanium dioxide coatings of bovine hides on light absorption and transdermal transfer of light-derived heat were investigated. Four hair-on rug hides from Holstein cattle were purchased. Twelve samples about 20 cm on a side were cut from each hide; nine from the black-colored areas, and three from the white areas. Samples were randomized and assigned to four coating treatments: (1) white hide with no coating (White), (2) black hide with no coating (Black), (3) black hide with 50% coating (Mid), and (4) black hide with 100% coating (High). Coatings were applied to the black hide samples using a hand sprayer. Lux measurements were taken using a modified lux meter at three light intensities generated with a broad spectrum, cold halogen light source. Reflectance over a wavelength range of 380 to 900 nm was measured using a spectroradiometer. The transdermal transfer of heat derived from absorbed light was measured by applying a broad spectrum, cold halogen light source to the stratum corneum (coated) side of the sample and recording the temperature of the dermis-side using a thermal camera for 10 min at 30-s intervals. At the high light level, the White, Black, Mid, and High coating treatments had different ( P 400 to 750 nm), Black hides reflected 10 to 15% of the light energy, hides with the Mid coating treatment reflected 35 to 40%, and hides with the High coating treatment reflected 70 to 80% of the light energy. The natural White hide samples reflected 60 to 80% of the light energy. The average maximum temperatures at the dermis-side of the hides due to transferred heat were 34.5, 70.1, 55.0, and 31.7, for the White, Black, Mid, and High treatments, respectively. Reflective coatings containing titanium dioxide on cattle hides were effective in reducing light energy absorption and reduced light-derived heat transfer from the skin surface to deeper skin layers.

β-Adrenergic blockade does not impair the skin blood flow sensitivity to local heating in burned and nonburned skin under neutral and hot environments in children.

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Rivas, Eric; McEntire, Serina J; Herndon, David N; Mlcak, Ronald P; Suman, Oscar E

2017-05-01

We tested the hypothesis that propranolol, a drug given to burn patients to reduce hypermetabolism/cardiac stress, may inhibit heat dissipation by changing the sensitivity of skin blood flow (SkBF) to local heating under neutral and hot conditions. In a randomized double-blind study, a placebo was given to eight burned children, while propranolol was given to 13 burned children with similar characteristics (mean±SD: 11.9±3 years, 147±20 cm, 45±23 kg, 56±12% Total body surface area burned). Nonburned children (n=13, 11.4±3 years, 152±15 cm, 52±13 kg) served as healthy controls. A progressive local heating protocol characterized SkBF responses in burned and unburned skin and nonburned control skin under the two environmental conditions (23 and 34°C) via laser Doppler flowmetry. Resting SkBF was greater in burned and unburned skin compared to the nonburned control (main effect: skin, Pburned; 38±36 unburned vs 9±8 control %SkBF max ). No difference was found for maximal SkBF capacity to local heating between groups. Additionally, dose-response curves for the sensitivity of SkBF to local heating were not different among burned or unburned skin, and nonburned control skin (EC 50 , P>.05) under either condition. Therapeutic propranolol does not negatively affect SkBF under neutral or hot environmental conditions and further compromise temperature regulation in burned children. © 2017 John Wiley & Sons Ltd.

Treatment of skin damage due to irradiation and post-irradiation skin tumours, at the Hornheide special clinic

International Nuclear Information System (INIS)

Drepper, H.

1987-01-01

A short precis of 54 years of history of the Hornheide special clinic for tumours, tuberculosis, and plastic surgery of face and skin is followed by a description of the current tasks of the clinic as an interdisciplinary center for plastic surgery and rehabilitation with facilities for tumour surgery, radiotherapy, skin and tissue pathology, and psychotherapy. Important special areas of this interdisciplinary cooperation are the treatment of skin disorders due to radiation and of tumours on irradiated skin, as well as treatment and plastic surgery after removal of tumours by irradiation in order to make the affected areas fit for renewed irradiation. (TRV) [de

β-adrenergic blockade does not impair the skin blood flow sensitivity to local heating in burned and non-burned skin under neutral and hot environments in children

Science.gov (United States)

Rivas, Eric; McEntire, Serina J.; Herndon, David N.; Mlcak, Ronald P.; Suman, Oscar E.

2017-01-01

Objective Tested the hypothesis that propranolol, a drug given to burn patients to reduce hypermetabolism/cardiac stress, may inhibit heat dissipation by changing the sensitivity of skin blood flow (SkBF) to local heating under neutral and hot conditions. Methods In a randomized double-blind study, a placebo was given to 8 burned children while propranolol was given to 13 burned children with similar characteristics (mean ± SD: 11.9±3y, 147±20cm, 45±23kg, 56±12% TBSA). Non-burned children (n=13, 11.4±3y, 152±15cm, 52±13kg) served as healthy controls. A progressive local heating protocol characterized SkBF responses in burned and unburned skin and non-burned control skin under the two environmental conditions (23°C and 34°C) via laser-Doppler flowmetry. Results Resting SkBF was greater in burned and unburned skin compared to the non-burned control (main effect: skin, Pburned; 38±36 unburned vs 9±8 control %SkBFmax). No difference was found for maximal SkBF capacity to local heating between groups. Additionally, dose response curves for the sensitivity of SkBF to local heating were not different among burned or unburned skin, and non-burned control skin (EC50, P>0.05) under either condition. Conclusion Therapeutic propranolol does not negatively affect SkBF under neutral or hot environmental conditions and further compromise temperature regulation in burned children. PMID:28071840

Skin cooling maintains cerebral blood flow velocity and orthostatic tolerance during tilting in heated humans

Science.gov (United States)

Wilson, Thad E.; Cui, Jian; Zhang, Rong; Witkowski, Sarah; Crandall, Craig G.

2002-01-01

Orthostatic tolerance is reduced in the heat-stressed human. The purpose of this project was to identify whether skin-surface cooling improves orthostatic tolerance. Nine subjects were exposed to 10 min of 60 degrees head-up tilting in each of four conditions: normothermia (NT-tilt), heat stress (HT-tilt), normothermia plus skin-surface cooling 1 min before and throughout tilting (NT-tilt(cool)), and heat stress plus skin-surface cooling 1 min before and throughout tilting (HT-tilt(cool)). Heating and cooling were accomplished by perfusing 46 and 15 degrees C water, respectively, though a tube-lined suit worn by each subject. During HT-tilt, four of nine subjects developed presyncopal symptoms resulting in the termination of the tilt test. In contrast, no subject experienced presyncopal symptoms during NT-tilt, NT-tilt(cool), or HT-tilt(cool). During the HT-tilt procedure, mean arterial blood pressure (MAP) and cerebral blood flow velocity (CBFV) decreased. However, during HT-tilt(cool), MAP, total peripheral resistance, and CBFV were significantly greater relative to HT-tilt (all P heat-stressed humans.

Treatment of Implant Exposure due to Skin Necroses after Skin Sparing Mastectomy: Initial Experiences Using a Not Selective Random Epigastric Flap.

Science.gov (United States)

Echazarreta-Gallego, Estíbaliz; Pola-Bandrés, Guillermo; Arribas-Del Amo, María Dolores; Gil-Romea, Ismael; Sousa-Domínguez, Ramón; Güemes-Sánchez, Antonio

2017-10-01

Breast prostheses exposure is probably the most devastating complication after a skin sparing mastectomy (SSM) and implant-based, one-stage, breast reconstruction. This complication may occur in the immediate post-operative period or in the weeks and even months after the procedure. In most cases, the cause is poor skin coverage of the implant due to skin necrosis. Eight consecutive cases of implant exposure (or risk of exposure) due to skin necrosis in SSM patients over a period of 5 years, all patients were treated using a random epigastric rotation flap, executed by the same medical team. A random epigastric flap (island or conventional rotation flap) was used to cover the skin defect. All the patients completed the procedure and all prostheses were saved; there were no cases of flap necrosis or infection. Cases of skin necrosis after SSM and immediate implant reconstruction, in which the implant is at risk of exposure, can be successfully treated with a random epigastric rotation flap.

Molecular action mechanisms of solar infrared radiation and heat on human skin.

Science.gov (United States)

Akhalaya, M Ya; Maksimov, G V; Rubin, A B; Lademann, J; Darvin, M E

2014-07-01

The generation of ROS underlies all solar infrared-affected therapeutic and pathological cutaneous effects. The signaling pathway NF-kB is responsible for the induced therapeutic effects, while the AP-1 for the pathological effects. The different signaling pathways of infrared-induced ROS and infrared-induced heat shock ROS were shown to act independently multiplying the influence on each other by increasing the doses of irradiation and/or increasing the temperature. The molecular action mechanisms of solar infrared radiation and heat on human skin are summarized and discussed in detail in the present paper. The critical doses are determined. Protection strategies against infrared-induced skin damage are proposed. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitative assessment of skin erythema due to radiotherapy--evaluation of different measurements

International Nuclear Information System (INIS)

Wengstroem, Yvonne; Forsberg, Christina; Naeslund, Ingemar; Bergh, Jonas

2004-01-01

Background and purpose: Visual assessment is the most common clinical investigation of skin reactions in radiotherapy. Due to the unquantitative and subjective nature of this method additional non-invasive methods are needed for more accurate evaluation of the visible acute adverse skin reactions due to radiotherapy. The purpose of this study was to evaluate a new objective measure with regard to reliability and validity and compare it with an established objective measure and a visual assessment. Patients and methods: A sample of 53 consecutive patients commencing curative tangential radiation therapy to the breast parenchyma were included in the study. The skin area of the treated breast was divided into five sections and assessed individually at 0, 24 and 50 Gy. The RTOG scoring system was used for the visual assessment of the skin reactions. The first objective measure included reflectance spectrometry (DermaSpectrometer) measures at fixed points within the treatment area. For the second objective measure digital images (Camera) were taken with a system using a digital camera and software. The images were analyzed using the Adobe Photoshop 5.0 software program. Results: The results provided significant evidence of the test-retest reliability of the camera. The correlation between the objective measures proved to be significant as the treatment progressed. Conclusions: The results suggest that the camera may be used in a reliable and valid way to measure skin erythema due to radiotherapy

Mechano-sensitive nociceptors are required to detect heat pain thresholds and cowhage itch in human skin.

Science.gov (United States)

Weinkauf, B; Dusch, M; van der Ham, J; Benrath, J; Ringkamp, M; Schmelz, M; Rukwied, R

2016-02-01

Mechano-sensitive and mechano-insensitive C-nociceptors in human skin differ in receptive field sizes and electrical excitation thresholds, but their distinct functional roles are yet unclear. After blocking the lateral femoral cutaneous nerve (NCFL) in eight healthy male subjects (3-mL Naropin(®) 1%), we mapped the skin innervation territory being anaesthetic to mechanical pin prick but sensitive to painful transcutaneous electrical stimuli. Such 'differentially anaesthetic zones' indicated that the functional innervation with mechano-sensitive nociceptors was absent but the innervation with mechano-insensitive nociceptors remained intact. In these areas, we explored heat pain thresholds, low pH-induced pain, cowhage- and histamine-induced itch, and axon reflex flare. In differentially anaesthetic skin, heat pain thresholds were above the cut-off of 50°C (non-anaesthetized skin 47 ± 0.4°C). Pain ratings to 30 μL pH 4 injections were reduced compared to non-anaesthetized skin (48 ± 9 vs. 79 ± 6 VAS; p pain. The mechano-sensitive nociceptors are crucial for cowhage-induced itch and for the assessment of heat pain thresholds. © 2015 European Pain Federation - EFIC®

Skin tightening.

Science.gov (United States)

Woolery-Lloyd, Heather; Kammer, Jenna N

2011-01-01

Skin tightening describes the treatment of skin laxity via radiofrequency (RF), ultrasound, or light-based devices. Skin laxity on the face is manifested by progressive loss of skin elasticity, loosening of the connective tissue framework, and deepening of skin folds. This results in prominence of submandibular and submental tissues. Genetic factors (chronological aging) and extrinsic factors (ultraviolet radiation) both contribute to skin laxity. There are many RF, ultrasound, and light-based devices directed at treating skin laxity. All of these devices target and heat the dermis to induce collagen contraction. Heating of the dermis causes collagen denaturation and immediate collagen contraction in addition to long-term collagen remodeling. Via RF, light, or ultrasound, these skin tightening devices deliver heat to the dermis to create new collagen and induce skin tightening. This chapter will provide an overview of the various skin tightening devices. Copyright © 2011 S. Karger AG, Basel.

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

Observation of the skin-like profiles of electron temperature and density of turbulently heated plasmas in the TRIAM-1 tokamak

International Nuclear Information System (INIS)

Hiraki, Naoji; Nakamura, Kazuo; Toi, Kazuo; Itoh, Satoshi

1980-01-01

The time evolution of electron temperature and density profiles are measured on the turbulent heating experiment in the TRIAM-1 tokamak. The skin-like profiles of electron temperature and density are observed just after the application of the pulsed electric field for turbulent heating. The width of the skin layer of the electron temperature profile is about 1 cm, and agrees well with the theoretical value. The above mentioned skin heating of electrons just after the heating pulse is also spectroscopically confirmed by the remarkable decrease of the volume emission of visible lines which is localized at the outer plasma region. (author)

Observation of the skin-like profiles of electron temperature and density of turbulently heated plasmas in the TRIAM-1 tokamak

Energy Technology Data Exchange (ETDEWEB)

Hiraki, N; Nakamura, K; Toi, K; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1980-07-01

The time evolution of electron temperature and density profiles are measured on the turbulent heating experiment in the TRIAM-1 tokamak. The skin-like profiles of electron temperature and density are observed just after the application of the pulsed electric field for turbulent heating. The width of the skin layer of the electron temperature profile is about 1 cm, and agrees well with the theoretical value. The above mentioned skin heating of electrons just after the heating pulse is also spectroscopically confirmed by the remarkable decrease of the volume emission of visible lines which is localized at the outer plasma region.

Modeling skin temperature to assess the effect of air velocity to mitigate heat stress among growing pigs

DEFF Research Database (Denmark)

Bjerg, Bjarne; Pedersen, Poul; Morsing, Svend

2017-01-01

It is generally accepted that increased air velocity can help to mitigate heat stress in livestock housing, however, it is not fully clear how much it helps and significant uncertainties exists when the air temperature approaches the animal body temperature. This study aims to develop a skin...... temperature model to generated data for determining the potential effect of air velocity to mitigate heat stress among growing pigs housed in warm environment. The model calculates the skin temperature as function of body temperature, air temperature and the resistances for heat transfer from the body...

Heating of a dense plasma by an ultrashort laser pulse in the anomalous skin-effect regime

International Nuclear Information System (INIS)

Andreev, A.A.; Gamalii, E.G.; Novikov, V.N.; Semakhin, A.N.; Tikhonchuk, V.T.

1992-01-01

The absorption of laser light in an overdense plasma with a sharp boundary and the heating of the plasma under conditions corresponding to the anomalous skin effect are studied. Heat transfer from the absorption region near the surface into the interior of the plasma is studied in the kinetic approximation. At high intensities of the laser pulse, the electron distribution function is deformed, and the plasma is heated at a rate tens of times that predicted by classical heat-transfer theory, because of the severe limitation on thermal conductivity. The anisotropy of the electron distribution function in the skin layer leads to an increase in the absorption coefficient. The angular distribution and the polarization dependence of the absorption coefficient are discussed

Assessing complexity of skin blood flow oscillations in response to locally applied heating and pressure in rats: Implications for pressure ulcer risk

Science.gov (United States)

Liao, Fuyuan; O'Brien, William D.; Jan, Yih-Kuen

2013-10-01

The objective of this study was to investigate the effects of local heating on the complexity of skin blood flow oscillations (BFO) under prolonged surface pressure in rats. Eleven Sprague-Dawley rats were studied: 7 rats underwent surface pressure with local heating (△t=10 °C) and 4 rats underwent pressure without heating. A pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin blood flow was measured using laser Doppler flowmetry. The loading period was divided into nonoverlapping 30 min epochs. For each epoch, multifractal detrended fluctuation analysis (MDFA) was utilized to compute DFA coefficients and complexity of endothelial related metabolic, neurogenic, and myogenic frequencies of BFO. The results showed that under surface pressure, local heating led to a significant decrease in DFA coefficients of myogenic frequency during the initial epoch of loading period, a sustained decrease in complexity of myogenic frequency, and a significantly higher degree of complexity of metabolic frequency during the later phase of loading period. Surrogate tests showed that the reduction in complexity of myogenic frequency was associated with a loss of nonlinearity whereas increased complexity of metabolic frequency was associated with enhanced nonlinearity. Our results indicate that increased metabolic activity and decreased myogenic response due to local heating manifest themselves not only in magnitudes of metabolic and myogenic frequencies but also in their structural complexity. This study demonstrates the feasibility of using complexity analysis of BFO to monitor the ischemic status of weight-bearing skin and risk of pressure ulcers.

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.

Local heat stress and skin blood flowmotion in subjects with familial predisposition or newly diagnosed hypertension.

Science.gov (United States)

Gryglewska, Barbara; Nęcki, Mirosław; Cwynar, Marcin; Baron, Tomasz; Grodzicki, Tomasz

2010-12-01

The aim of the study was to investigate the skin microcirculation blood flow and flowmotion response to heat stress in normotensive subjects with familial predisposition to hypertension and in hypertensive patients. Normotensives without [NT(-)] or with [NT(+)] familial predisposition and subjects with newly diagnosed hypertension (HT) were studied. Clinic blood pressure (BP) measurements and ambulatory BP monitoring as well as laboratory assessments were performed. Resting (RF), heat (HF) and maximal heat (MHF) blood flows were measured using PeriFlux laser Doppler flowmetry (LDF) and expressed as absolute units (AU) and as index of cutaneous vascular conductance (CVC). Spectral analysis of the skin LDF signal was performed by means of the Perisoft dedicated software. Kruskall-Wallis analysis of variance, χ(2) statistic and multivariate reverse regression analysis were used for calculation. The studied population consisted of 70 persons (mean age 36.1 ± 10.3 years, 44.3% women): 17 NT(-), 22 NT(+) and 31 HT, age and gender matched. Higher values of body mass index (BMI), and insulin, glucose and triglyceride levels were observed in HT than in NT groups. RF, HF and MHF were similar in all study groups, but CVC of maximal heat flow differed (p=0.02); in particular, lower values were observed in the HT than in NT(-) group (p=0.01). The study groups differed with regard to total power (p=0.01) and myogenic (p=0.03) origin flowmotion with the lowest values in the NT(+) group. BMI and night BP characteristics were strong predictors of reduction of CVC, MHF and myogenic origin flowmotion. Skin microcirculation response to local heat stress is altered in hypertensive patients with decrease in maximal heat CVC values. Moreover, normotensive subjects with familial predisposition to hypertension are characterized by diminished myogenic origin of skin blood flowmotion.

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.

Personalized Hydration Strategy Attenuates the Rise in Heart Rate and in Skin Temperature Without Altering Cycling Capacity in the Heat.

Science.gov (United States)

de Melo-Marins, Denise; Souza-Silva, Ana Angélica; da Silva-Santos, Gabriel Lucas Leite; Freire-Júnior, Francisco de Assis; Lee, Jason Kai Wei; Laitano, Orlando

2018-01-01

The optimal hydration plan [i.e., drink to thirst, ad libitum (ADL), or personalized plan] to be adopted during exercise in recreational athletes has recently been a matter of debate and, due to conflicting results, consensus does not exist. In the present investigation, we tested whether a personalized hydration strategy based on sweat rate would affect cardiovascular and thermoregulatory responses and exercise capacity in the heat. Eleven recreational male cyclists underwent two familiarization cycling sessions in the heat (34°C, 40% RH) where sweat rate was also determined. A fan was used to enhance sweat evaporation. Participants then performed three randomized time-to-exhaustion (TTE) trials in the heat with different hydration strategies: personalized volume (PVO), where water was consumed, based on individual sweat rate, every 10 min; ADL, where free access to water was allowed; and a control (CON) trial with no fluids. Blood osmolality and urine-specific gravity were measured before each trial. Heart rate (HR), rectal, and skin temperatures were monitored throughout trials. Time to exhaustion at 70% of maximal workload was used to define exercise capacity in the heat, which was similar in all trials ( p  = 0.801). Body mass decreased after ADL ( p  = 0.008) and CON ( p  skin temperature during PVO trial in comparison with CON (2.1 ± 0.6 vs. 2.9 ± 0.5°C, p  = 0.0038). HR was lower toward the end of TTE in PVO (162 ± 8 bpm) in comparison with ADL (168 ± 12 bpm) and CON (167 ± 10 bpm), p  hydration strategy can reduce HR during a moderate to high intensity exercise session in the heat and halt the increase in skin temperature. Despite these advantages, cycling capacity in the heat remained unchanged.

Neural and non-neural control of skin blood flow during isometric handgrip exercise in the heat stressed human

DEFF Research Database (Denmark)

Shibasaki, M.; Rasmussen, P.; Secher, Niels H.

2009-01-01

as an absence of sweating and cutaneous vasodilatation during a whole-body heat stress. Upon this confirmation, adenosine was perfused through one of the microdialysis probes to increase skin blood flow similar to that of the unblocked site. After internal temperature increased approximately 0.7 degrees C......During heat stress, isometric handgrip (IHG) exercise causes cutaneous vasoconstriction, but it remains controversial whether neural mechanisms are responsible for this observation. The objective of this study was to test the hypothesis that cutaneous vasoconstriction during IHG exercise in heat...... stressed individuals occurs via a neural mechanism. An axillary nerve blockade was performed to block efferent nerve traffic to the left forearm in seven healthy subjects. Two intradermal microdialysis probes were placed within forearm skin of the blocked area. Forearm skin blood flow was measured by laser...

Arteriographic features of rare skin complications due to chronic osteomyelitis

International Nuclear Information System (INIS)

Boehm, E.; Wiebe, V.; Oelenberg, W.; Berufsgenossenschaftliche Krankenanstalten 'Bergmannsheil' Bochum

1984-01-01

In the period between 1970 and 1982, 6 carcinomas in scar tissue and 2 pseudocarcinomatous skin papillomatoses were found on the basis of chronic osteomyelitides. Amputation specimens of two carcinomas and one papillomatosis were examined by arteriography. Macroscopically carcinomas in scar tissue showed an unspecific appearance and microscopically a scarefied and partly pathological vascular appearance. Pseudocarcinomatous skin papillomatosis was distinctly hypervascular. Therefore, indications with regard to the localisation of an required exploratory excision can only be obtained from the vascular appearance of papillomatosis but not in case of a scar tissue carcinoma after osteomyelitis. Due to the overall bad blood circulation osteomyelitic scar tissue carcinoma scarcely reacts positively to a chemotherapeutic treatment. (orig.) [de

Influence of angle between the nozzle and skin surface on the heat flux and overall heat extraction during cryogen spray cooling

International Nuclear Information System (INIS)

Aguilar, Guillermo; Vu, Henry; Nelson, J Stuart

2004-01-01

High speed video imaging and an inverse heat conduction problem algorithm were used to observe and measure the effect of the angle between the nozzle and surface of a skin phantom on: (a) surface temperature; (b) heat flux q; and (c) overall heat extraction Q during cryogen spray cooling (CSC). A skin phantom containing a fast-response temperature sensor was sprayed with 50 ms cryogen spurts from a commercial nozzle placed 30 mm from the surface. The nozzle was systematically positioned at angles ranging from 5 deg. to 90 deg. (perpendicular) with respect to the phantom surface. It is shown that angles as low as 15 deg. have an insignificant impact on the surface temperature, q and Q. Only exaggerated angles of 5 deg. show up to 10% lower q and 30% lower Q with respect to the maximal values measured when nozzles are aimed perpendicularly. This study proves that the slight angle that many commercial nozzles have does not affect significantly the CSC efficiency. (note)

The effect of nerve blockade on forearm and finger skin blood flow during body heating and cooling.

Science.gov (United States)

Saumet, J L; Degoute, C S; Saumet, M; Abraham, P

1992-08-01

To determine the role of the active cutaneous vasodilatator response in forearm and finger skin, direct assessment of only skin blood flow was performed before and after musculocutaneous and median nerve blockade during whole body heating and cooling. Forearm laser Doppler flow (LDF forearm), forearm heat thermal clearance (HTC forearm), and finger laser Doppler flow (LDF finger) were monitored in the nerve blocked skin and contralateral untreated skin (control). In the pre-blockade period, no significant differences were found between experimental and control arm skin. After nerve block a significant increase occurred only in LDF finger, which rose from 4.3 +/- 0.6 to 6.0 +/- 0.5 volts (p less than 0.05). During whole body heating LDF forearm and HTC forearm increased significantly on both arms. The increase in LDF forearm was greater (p less than 0.05) in control (18.3 +/- 1.2 volts) than in nerve blocked skin (14.6 +/- 1.8 volts) and occurred earlier. The same tendency was observed in HTC forearm between nerve blocked skin (0.522 +/- 0.06 W.m-1.degrees C-1) and control 0.671 +/- 0.037 W.m-1.degrees C-1) (NS). LDF raise up to 6.6 +/- 0.5 and 6.8 +/- 0.5 volts in the blocked finger and in the control respectively. During cooling LDF finger in the control decreased to 1.3 +/- 0.1 volt and was significantly (p less than 0.05) lower than in the resting period, and lower than that in the nerve blocked finger (3.4 +/- 0.8 volts) (p less than 0.05). We conclude that the active vasodilatator system plays an important role as far as the timing and the amplitude of the cutaneous vasodilatator response to whole body heating in the forearm but not in the finger. At thermal neutrality, the vascular vasoconstrictor tone is high to the finger but not to the forearm. The vasoconstrictor response to cooling occurred only in the finger.

Microwave Heating of Synthetic Skin Samples for Potential Treatment of Gout Using the Metal-Assisted and Microwave-Accelerated Decrystallization Technique.

Science.gov (United States)

Toker, Salih; Boone-Kukoyi, Zainab; Thompson, Nishone; Ajifa, Hillary; Clement, Travis; Ozturk, Birol; Aslan, Kadir

2016-11-30

Physical stability of synthetic skin samples during their exposure to microwave heating was investigated to demonstrate the use of the metal-assisted and microwave-accelerated decrystallization (MAMAD) technique for potential biomedical applications. In this regard, optical microscopy and temperature measurements were employed for the qualitative and quantitative assessment of damage to synthetic skin samples during 20 s intermittent microwave heating using a monomode microwave source (at 8 GHz, 2-20 W) up to 120 s. The extent of damage to synthetic skin samples, assessed by the change in the surface area of skin samples, was negligible for microwave power of ≤7 W and more extensive damage (>50%) to skin samples occurred when exposed to >7 W at initial temperature range of 20-39 °C. The initial temperature of synthetic skin samples significantly affected the extent of change in temperature of synthetic skin samples during their exposure to microwave heating. The proof of principle use of the MAMAD technique was demonstrated for the decrystallization of a model biological crystal (l-alanine) placed under synthetic skin samples in the presence of gold nanoparticles. Our results showed that the size (initial size ∼850 μm) of l-alanine crystals can be reduced up to 60% in 120 s without damage to synthetic skin samples using the MAMAD technique. Finite-difference time-domain-based simulations of the electric field distribution of an 8 GHz monomode microwave radiation showed that synthetic skin samples are predicted to absorb ∼92.2% of the microwave radiation.

Microwave Heating of Synthetic Skin Samples for Potential Treatment of Gout Using the Metal-Assisted and Microwave-Accelerated Decrystallization Technique

Science.gov (United States)

2016-01-01

Physical stability of synthetic skin samples during their exposure to microwave heating was investigated to demonstrate the use of the metal-assisted and microwave-accelerated decrystallization (MAMAD) technique for potential biomedical applications. In this regard, optical microscopy and temperature measurements were employed for the qualitative and quantitative assessment of damage to synthetic skin samples during 20 s intermittent microwave heating using a monomode microwave source (at 8 GHz, 2–20 W) up to 120 s. The extent of damage to synthetic skin samples, assessed by the change in the surface area of skin samples, was negligible for microwave power of ≤7 W and more extensive damage (>50%) to skin samples occurred when exposed to >7 W at initial temperature range of 20–39 °C. The initial temperature of synthetic skin samples significantly affected the extent of change in temperature of synthetic skin samples during their exposure to microwave heating. The proof of principle use of the MAMAD technique was demonstrated for the decrystallization of a model biological crystal (l-alanine) placed under synthetic skin samples in the presence of gold nanoparticles. Our results showed that the size (initial size ∼850 μm) of l-alanine crystals can be reduced up to 60% in 120 s without damage to synthetic skin samples using the MAMAD technique. Finite-difference time-domain-based simulations of the electric field distribution of an 8 GHz monomode microwave radiation showed that synthetic skin samples are predicted to absorb ∼92.2% of the microwave radiation. PMID:27917407

The Clinical Test of Nano gold Cosmetic for Recovering Skin Damage Due to Chemicals: Special Case

Science.gov (United States)

Taufikurohmah, T.; Wardana, A. P.; Tjahjani, S.; Sanjaya, I. G. M.; Baktir, A.; Syahrani, A.

2018-01-01

Manufacturing of Nano gold cosmetics was done at PT. Gizi Indonesia. Clinical trials to cosmetics data supported that cosmetics are able to treat skin health which has been reported partially. For special cases, the recovery process of facial skin damage should also receive attention including cases of facial skin damage caused by chemicals such as phenol, HCl, aqua regia or other harsh chemicals. The problem determined whether the Nano gold is able to recover skin damage due to the harsh chemicals. This clinical trial data on the forms of early skin damage caused by phenol was delivered in the forms of facial photos patients. The recovery progress of facial skin condition was obtained every week for two months. The data included the forms of widespread wounds during the recovery process. This statement supported by anova statistical analysis of the widespread wound changing every week for 8 times. The conclusion is skin damage due to Phenol impregnation can be recovered with the use of Nano gold cosmetics for 8 weeks. This results support the manufacturing of Nano gold cosmetics for the needs of society. It also suggest that Nano gold material can be used for medicine manufacturing in the future.

Time course of primary and secondary hyperalgesia after heat injury to the skin

DEFF Research Database (Denmark)

Møiniche, S; Dahl, J B; Kehlet, H

1993-01-01

the injury in any volunteer. These findings suggest post-injury development of secondary hyperalgesia to be a dynamic process, closely related in time to a peripheral nociceptive input, with reversal to normal when the peripheral lesion disappears. These observations may be relevant to the concept of "pre......We have examined the time course of, and relationship between, primary and secondary hyperalgesia after thermal injury to the skin in humans. Burn injuries (15 x 25 mm rectangular thermode, 49 degrees C, 5 min) were produced in eight healthy, unmedicated male volunteers, on the medial side...... of the right calf, on two occasions at least 8 days apart. Heat pain detection thresholds (HPDT), heat pain tolerance (HPT), mechanical pain detection threshold (MPDT) and the intensity of burn-injury induced erythema (skin erythema index, SEI) were assessed inside the burn injury. HPT was assessed only in one...

Responses to hyperthermia. Optimizing heat dissipation by convection and evaporation: Neural control of skin blood flow and sweating in humans.

Science.gov (United States)

Smith, Caroline J; Johnson, John M

2016-04-01

Under normothermic, resting conditions, humans dissipate heat from the body at a rate approximately equal to heat production. Small discrepancies between heat production and heat elimination would, over time, lead to significant changes in heat storage and body temperature. When heat production or environmental temperature is high the challenge of maintaining heat balance is much greater. This matching of heat elimination with heat production is a function of the skin circulation facilitating heat transport to the body surface and sweating, enabling evaporative heat loss. These processes are manifestations of the autonomic control of cutaneous vasomotor and sudomotor functions and form the basis of this review. We focus on these systems in the responses to hyperthermia. In particular, the cutaneous vascular responses to heat stress and the current understanding of the neurovascular mechanisms involved. The available research regarding cutaneous active vasodilation and vasoconstriction is highlighted, with emphasis on active vasodilation as a major responder to heat stress. Involvement of the vasoconstrictor and active vasodilator controls of the skin circulation in the context of heat stress and nonthermoregulatory reflexes (blood pressure, exercise) are also considered. Autonomic involvement in the cutaneous vascular responses to direct heating and cooling of the skin are also discussed. We examine the autonomic control of sweating, including cholinergic and noncholinergic mechanisms, the local control of sweating, thermoregulatory and nonthermoregulatory reflex control and the possible relationship between sudomotor and cutaneous vasodilator function. Finally, we comment on the clinical relevance of these control schemes in conditions of autonomic dysfunction. Copyright © 2016 Elsevier B.V. All rights reserved.

Calculation of heat generation due to nuclear radiation in nuclear reactors

International Nuclear Information System (INIS)

Torres, L.M.R.; Gomes, I.C.; Maiorino, J.R.

1986-01-01

The study is performed for caculating nuclear heating due to the interaction of neutrons and gamma-rays with matter. Modifications were implemented in the ANISN code, that solves the one-dimensional transport equation using the discrete ordinate method, to include nuclear heating calculations. Tests of the implemented modifications were performed in problems of nuclear heating due to radiation energy deposition in a fusion reactor. (Author) [pt

Personalized Hydration Strategy Attenuates the Rise in Heart Rate and in Skin Temperature Without Altering Cycling Capacity in the Heat

Directory of Open Access Journals (Sweden)

Denise de Melo-Marins

2018-04-01

Full Text Available The optimal hydration plan [i.e., drink to thirst, ad libitum (ADL, or personalized plan] to be adopted during exercise in recreational athletes has recently been a matter of debate and, due to conflicting results, consensus does not exist. In the present investigation, we tested whether a personalized hydration strategy based on sweat rate would affect cardiovascular and thermoregulatory responses and exercise capacity in the heat. Eleven recreational male cyclists underwent two familiarization cycling sessions in the heat (34°C, 40% RH where sweat rate was also determined. A fan was used to enhance sweat evaporation. Participants then performed three randomized time-to-exhaustion (TTE trials in the heat with different hydration strategies: personalized volume (PVO, where water was consumed, based on individual sweat rate, every 10 min; ADL, where free access to water was allowed; and a control (CON trial with no fluids. Blood osmolality and urine-specific gravity were measured before each trial. Heart rate (HR, rectal, and skin temperatures were monitored throughout trials. Time to exhaustion at 70% of maximal workload was used to define exercise capacity in the heat, which was similar in all trials (p = 0.801. Body mass decreased after ADL (p = 0.008 and CON (p < 0.001 and was maintained in PVO trials (p = 0.171. Participants consumed 0 ml in CON, 166 ± 167 ml in ADL, and 1,080 ± 166 ml in PVO trials. The increase in mean body temperature was similar among trials despite a lower increase in skin temperature during PVO trial in comparison with CON (2.1 ± 0.6 vs. 2.9 ± 0.5°C, p = 0.0038. HR was lower toward the end of TTE in PVO (162 ± 8 bpm in comparison with ADL (168 ± 12 bpm and CON (167 ± 10 bpm, p < 0.001. In conclusion, a personalized hydration strategy can reduce HR during a moderate to high intensity exercise session in the heat and halt the increase in skin

Reproducibility of the heat/capsaicin skin sensitization model in healthy volunteers

Directory of Open Access Journals (Sweden)

Cavallone LF

2013-11-01

Full Text Available Laura F Cavallone,1 Karen Frey,1 Michael C Montana,1 Jeremy Joyal,1 Karen J Regina,1 Karin L Petersen,2 Robert W Gereau IV11Department of Anesthesiology, Washington University in St Louis, School of Medicine, St Louis, MO, USA; 2California Pacific Medical Center Research Institute, San Francisco, CA, USAIntroduction: Heat/capsaicin skin sensitization is a well-characterized human experimental model to induce hyperalgesia and allodynia. Using this model, gabapentin, among other drugs, was shown to significantly reduce cutaneous hyperalgesia compared to placebo. Since the larger thermal probes used in the original studies to produce heat sensitization are now commercially unavailable, we decided to assess whether previous findings could be replicated with a currently available smaller probe (heated area 9 cm2 versus 12.5–15.7 cm2.Study design and methods: After Institutional Review Board approval, 15 adult healthy volunteers participated in two study sessions, scheduled 1 week apart (Part A. In both sessions, subjects were exposed to the heat/capsaicin cutaneous sensitization model. Areas of hypersensitivity to brush stroke and von Frey (VF filament stimulation were measured at baseline and after rekindling of skin sensitization. Another group of 15 volunteers was exposed to an identical schedule and set of sensitization procedures, but, in each session, received either gabapentin or placebo (Part B.Results: Unlike previous reports, a similar reduction of areas of hyperalgesia was observed in all groups/sessions. Fading of areas of hyperalgesia over time was observed in Part A. In Part B, there was no difference in area reduction after gabapentin compared to placebo.Conclusion: When using smaller thermal probes than originally proposed, modifications of other parameters of sensitization and/or rekindling process may be needed to allow the heat/capsaicin sensitization protocol to be used as initially intended. Standardization and validation of

Vasomotion in human skin before and after local heating recorded with laser Doppler flowmetry. A method for induction of vasomotion

DEFF Research Database (Denmark)

Kastrup, J; Bülow, J; Lassen, N A

1989-01-01

neurogenic origin. A method for induction of regular amplified alpha-oscillations was discovered and evaluated. When heating the skin locally to 42 degrees C the blood cell flux increased and the pre-heating alpha- and beta-oscillations disappeared. During the post-heating period, amplified regular rhythmic......Rhythmical variations in blood cell flux in human skin have been studied using laser Doppler flowmetry. The fluctuations in blood cell flux could be divided into two different categories named alpha- and beta-oscillations with a median frequency of 6.8 min-1 and 1.5 min-1, respectively...... alpha-oscillations appeared. At the end of the post-heating period beta-oscillations re-appeared....

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.

Determination of skin blood flow by 133Xe washout and by heat flux from a heated tc-Po2 electrode

International Nuclear Information System (INIS)

Jaszczak, P.; Sejrsen, P.

1984-01-01

133 Xe washout measurements were used to determine cutaneous and subcutaneous blood flow beneath a specially designed double-thermostated tc-Po 2 electrode. The skin blood flow was determined using thermal methods based on reduced heat dissipation during blood flow cessation. A total of 20 measurements were performed on two healthy volunteers, using the volar side of the right forearm as the experimental area. Cutaneous as well as subcutaneous blood flow increased with increasing electrode temperature. The cutaneous blood flow increased from 12.3 +- 1.3 ml (100 g) -1 . min -1 (37degC) to 49.1 +- 5.4 ml (100g) -1 . min -1 (45degC) and the subcutaneous values from 20.9 +- 0.2 ml (100 g) -1 . min -1 to 57.3 +- 0.5 ml(100 g) -1 . min -1 . Preheating of the measuring area or injection of papaverine as blood flow accelerator did not increase the maximum blood flow values. A considerable inter-individual difference between cutaneous and subcutaneous blood flow was observed, but in spite of that a good overall correlation between the 133 Xe washout measurements and the two thermal flow measurements was found (r = 0.932 and 0.945, respectively). It is concluded that in some cases, but not always, measurements of tc-Po 2 at electrode temperatures of 45degC take place on a maximally perfused skin and that it is possible to determine skin blood flow by means of determinations of the heat dissipated from the tc-Po 2 electrode to the underlying skin. (author)

Microwave Heating of Synthetic Skin Samples for Potential Treatment of Gout Using the Metal-Assisted and Microwave-Accelerated Decrystallization Technique

OpenAIRE

Toker, Salih; Boone-Kukoyi, Zainab; Thompson, Nishone; Ajifa, Hillary; Clement, Travis; Ozturk, Birol; Aslan, Kadir

2016-01-01

Physical stability of synthetic skin samples during their exposure to microwave heating was investigated to demonstrate the use of the metal-assisted and microwave-accelerated decrystallization (MAMAD) technique for potential biomedical applications. In this regard, optical microscopy and temperature measurements were employed for the qualitative and quantitative assessment of damage to synthetic skin samples during 20 s intermittent microwave heating using a monomode microwave source (at 8 G...

Cold-induced vasoconstriction at forearm and hand skin sites: the effect of age

OpenAIRE

Kingma, B.R.M.; Frijns, A.J.H.; Saris, W.H.M.; Steenhoven, van, A.A.; Marken Lichtenbelt, van, W.D.

2010-01-01

During mild cold exposure, elderly are at risk of hypothermia. In humans, glabrous skin at the hands is well adapted as a heat exchanger. Evidence exists that elderly show equal vasoconstriction due to local cooling at the ventral forearm, yet no age effects on vasoconstriction at hand skin have been studied. Here, we tested the hypotheses that at hand sites (a) elderly show equal vasoconstriction due to local cooling and (b) elderly show reduced response to noradrenergic stimuli. Skin perfus...

Microwave Heating of Crystals with Gold Nanoparticles and Synovial Fluid under Synthetic Skin Patches.

Science.gov (United States)

McLemore, Gabrielle L; Toker, Salih; Boone-Kukoyi, Zainab; Ajifa, Hillary; Lansiquot, Carisse; Nwawulu, Chinenye; Onyedum, Stanley; Kioko, Bridgit M; Aslan, Kadir

2017-09-30

Gout is a disease with elusive treatment options. Reduction of the size of l-alanine crystals as a model crystal for gouty tophi with the use of a monomode solid-state microwave was examined as a possible therapeutic aid. The effect of microwave heating on l-alanine crystals in the presence of gold nanoparticles (Au NPs) in solution and synovial fluid (SF) in a plastic pouch through a synthetic skin patch was investigated. In this regard, three experimental paradigms were employed: Paradigm 1 includes the effect of variable microwave power (5-10 W) and variable heating time (5-60 s) and Au NPs in water (20 nm size, volume of 10 μL) in a plastic pouch (1 × 2 cm 2 in size). Paradigm 2 includes the effect of a variable volume of 20 nm Au NPs in a variable volume of SF up to 100 μL in a plastic pouch at a constant microwave power (10 W) for 30 s. Paradigm 3 includes the effect of constant microwave power (10 W) and microwave heating time (30 s), constant volume of Au NPs (100 μL), and variable size of Au NPs (20-200 nm) placed in a plastic pouch through a synthetic skin patch. In these experiments, an average of 60-100% reduction in the size of an l-alanine crystal (initial size = 450 μm) without damage to the synthetic skin or increasing the temperature of the samples beyond the physiological range was reported.

Skin necrosis in a critically ill patient due to a blood pressure cuff

Directory of Open Access Journals (Sweden)

Devbhandari Mohan

2006-01-01

Full Text Available The non-invasive method of blood pressure measurement is regarded as a safe procedure and the reports of any serious complications are rare. We report a unique case of extensive skin necrosis due to an intermittently inflating blood pressure cuff in a 65-year-old critically ill lady following a third time redo mitral valve surgery. A brief review of the literature on complications associated with noninvasive method of measurement of blood pressure is presented along with possible mechanisms of skin injury and ways to avoid it.

Effect of short-term heat acclimation on endurance time and skin blood flow in trained athletes

Directory of Open Access Journals (Sweden)

Chen TI

2013-06-01

Full Text Available Tsung-I Chen,1,2 Pu-Hsi Tsai,3 Jui-Hsing Lin,4 Ning-Yuean Lee,5 Michael TC Liang61Graduate Institute of Sport Science, National Taiwan Sport University, Taoyuan, 2Center for Physical Education, Tzu Chi University, Hualien, 3Department of Sport and Leisure, National Quemoy University, Kinmen, 4Department of Physical Education, National Pingtung University of Education, Pingtung, 5College of Living Technology, Tainan University of Technology, Tainan, Taiwan; 6Department of Kinesiology and Health Promotion, California State Polytechnic University, Pomona, CA, USABackground: To examine whether short-term, ie, five daily sessions, vigorous dynamic cycling exercise and heat exposure could achieve heat acclimation in trained athletes and the effect of heat acclimation on cutaneous blood flow in the active and nonactive limb.Methods: Fourteen male badminton and table tennis athletes (age = 19.6 ± 1.2 years were randomized into a heat acclimation (EXP, n = 7 or nonheat acclimation (CON, n = 7 group. For 5 consecutive days, the EXP group was trained using an upright leg cycle ergometer in a hot environment (38.4°C ± 0.4°C, while the CON group trained in a thermoneutral environment (24.1°C ± 0.3°C. For both groups, the training intensity and duration increased from a work rate of 10% below ventilatory threshold (VT and 25 minutes per session on day 1, to 10% above VT and 45 minutes per session on day 5. Subjects performed two incremental leg cycle exercise tests to exhaustion at baseline and post-training in both hot and thermoneutral conditions. Study outcome measurements include: maximum oxygen uptake (VO2max; exercise heart rate (HR; O2 pulse; exercise time to exhaustion (tmax; skin blood flow in the upper arm (SkBFa and quadriceps (SkBFq; and mean skin (Tsk.Results: The significant heat-acclimated outcome measurements obtained during high-intensity leg cycling exercise in the high ambient environment are: (1 56%–100% reduction in cutaneous

Resistive wall heating due to image current on the beam chamber for a superconducting undulator.

Energy Technology Data Exchange (ETDEWEB)

Kim, S. H. (Accelerator Systems Division (APS))

2012-03-27

The image-current heating on the resistive beam chamber of a superconducting undulator (SCU) was calculated based on the normal and anomalous skin effects. Using the bulk resistivity of copper for the beam chamber, the heat loads were calculated for the residual resistivity ratios (RRRs) of unity at room temperature to 100 K at a cryogenic temperature as the reference. Then, using the resistivity of the specific aluminum alloy 6053-T5, which will be used for the SCU beam chamber, the heat loads were calculated. An electron beam stored in a storage ring induces an image current on the inner conducting wall, mainly within a skin depth, of the beam chamber. The image current, with opposite charge to the electron beam, travels along the chamber wall in the same direction as the electron beam. The average current in the storage ring consists of a number of bunches. When the pattern of the bunched beam is repeated according to the rf frequency, the beam current may be expressed in terms of a Fourier series. The time structure of the image current is assumed to be the same as that of the beam current. For a given resistivity of the chamber inner wall, the application ofthe normal or anomalous skin effect will depend on the harmonic numbers of the Fourier series of the beam current and the temperature of the chamber. For a round beam chamber with a ratius r, much larger than the beam size, one can assume that the image current density as well as the density square, may be uniform around the perimeter 2{pi}r. For the SCU beam chamber, which has a relatively narrow vertical gap compared to the width, the effective perimeter was estimated since the heat load should be proportional to the inverse of the perimeter.

Thermoregulatory responses to skin wetting during prolonged treadmill running.

Science.gov (United States)

Bassett, D R; Nagle, F J; Mookerjee, S; Darr, K C; Ng, A V; Voss, S G; Napp, J P

1987-02-01

We examined the physiological responses to skin wetting during a 120-min level treadmill run to assess whether skin wetting would reduce the dehydration and the increase in core temperature associated with prolonged exercise. Testing was conducted in an environmental chamber (T = 29.5 degrees C, wind velocity = 3 m X sec-1) under two different humidity conditions (33 or 66% relative humidity). Ten male subjects performed two runs in each humidity condition; one served as a control run. The other included spraying the body with 50 ml of water (T = 29.5 degrees C) every 10 min. Spraying had no effect on rectal temperature (Tre), heart rate, oxygen consumption, perceived exertion, sweat loss, or percent change in plasma volume in both the humid and the dry conditions. Spraying produced a significant reduction in mean skin temperature (Tsk), which increased the (Tre - Tsk) gradient. At the same time, overall skin conductance (K) was decreased, presumably as a result of cutaneous vasoconstriction due to the low Tsk. Since heat transfer from the body's core to the skin is expressed by the equation: heat transfer = K X (Tre - Tsk) the spraying had no effect on heat transfer away from the core, and Tre remained unchanged.

Modeling Skin Injury from Hot Rice Porridge Spills

Directory of Open Access Journals (Sweden)

Torgrim Log

2018-04-01

Full Text Available The present work analyzes skin burns from spills of hot rice and milk products. The traditional Norwegian rice porridge serves as an example. By testing spills on objects emulating an arm, it was concluded that spills were seldom thinner than 3 mm, and stayed in place due to the viscosity of the porridge for more than one minute. The Pennes bioheat equation was solved numerically for such spills, including heat conduction to the skin and convective heat losses from the porridge surface. Temperatures were analyzed in the porridge and skin layers, and the resulting skin injury was calculated based on the basal layer temperature. Parameters influencing burn severity, such as porridge layer thickness, porridge temperature, removal of the porridge and thermal effects of post scald tempered (15 °C water cooling were analyzed. The spilled porridge resulted in a prolonged heat supply to the skin, and the skin injury developed significantly with time. The porridge temperature turned out to be the most important injury parameter. A 70 °C porridge temperature could develop superficial partial-thickness burns. Porridge temperatures at processing temperatures nearly instantly developed severe burns. It was demonstrated that prompt removal of the hot porridge significantly reduced the injury development. The general advice is to avoid serving porridge and similar products at temperatures above 65 °C and, if spilled on the skin, to remove it quickly. After such scald incidents, it is advised to cool the injured area by tempered water for a prolonged period to stimulate healing.

Spread of smoke and heat along narrow air cavity in double-skin façade fires

Directory of Open Access Journals (Sweden)

Chow Lun Cheuk

2014-01-01

Full Text Available A scenario on double-skin façade fire was identified earlier for hazard assessment. A flashover room fire occurred next to the façade, broke the interior glass pane and spread to the façade cavity. As observed in experiments, hot gas moved up as a vertical channel flow for narrow façade cavity. Heat and smoke spread along the narrow air cavity of a double-skin façade will be studied in this paper. A simple mathematical model is developed from basic heat transfer theory for studying the vertical air temperature profiles of the hot gas flowing along the cavity. Assuming one-dimensional flow for hot gas moving up the façade cavity, conservation equations on mass and enthalpy were solved. Experimental results on two double-skin façade rigs of height 6 m and 15 m with narrow cavity depth were used to justify the results. A total of 11 tests were carried out. Correlation expressions between cavity air temperature and the height above ceiling of the fire room were derived.

A comparison between conductive and infrared devices for measuring mean skin temperature at rest, during exercise in the heat, and recovery.

Science.gov (United States)

Bach, Aaron J E; Stewart, Ian B; Disher, Alice E; Costello, Joseph T

2015-01-01

Skin temperature assessment has historically been undertaken with conductive devices affixed to the skin. With the development of technology, infrared devices are increasingly utilised in the measurement of skin temperature. Therefore, our purpose was to evaluate the agreement between four skin temperature devices at rest, during exercise in the heat, and recovery. Mean skin temperature ([Formula: see text]) was assessed in thirty healthy males during 30 min rest (24.0 ± 1.2°C, 56 ± 8%), 30 min cycle in the heat (38.0 ± 0.5°C, 41 ± 2%), and 45 min recovery (24.0 ± 1.3°C, 56 ± 9%). [Formula: see text] was assessed at four sites using two conductive devices (thermistors, iButtons) and two infrared devices (infrared thermometer, infrared camera). Bland-Altman plots demonstrated mean bias ± limits of agreement between the thermistors and iButtons as follows (rest, exercise, recovery): -0.01 ± 0.04, 0.26 ± 0.85, -0.37 ± 0.98°C; thermistors and infrared thermometer: 0.34 ± 0.44, -0.44 ± 1.23, -1.04 ± 1.75°C; thermistors and infrared camera (rest, recovery): 0.83 ± 0.77, 1.88 ± 1.87°C. Pairwise comparisons of [Formula: see text] found significant differences (p heat and recovery. These results indicate poor agreement between conductive and infrared devices at rest, during exercise in the heat, and subsequent recovery. Infrared devices may not be suitable for monitoring [Formula: see text] in the presence of, or following, metabolic and environmental induced heat stress.

Cold-induced vasoconstriction at forearm and hand skin sites: the effect of age

NARCIS (Netherlands)

Kingma, B.R.M.; Frijns, A.J.H.; Saris, W.H.M.; Steenhoven, van A.A.; Marken Lichtenbelt, van W.D.

2010-01-01

During mild cold exposure, elderly are at risk of hypothermia. In humans, glabrous skin at the hands is well adapted as a heat exchanger. Evidence exists that elderly show equal vasoconstriction due to local cooling at the ventral forearm, yet no age effects on vasoconstriction at hand skin have

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.

Transient pool boiling heat transfer due to increasing heat inputs in subcooled water at high pressures

International Nuclear Information System (INIS)

Fukuda, K.; Shiotsu, M.; Sakurai, A.

1995-01-01

Understanding of transient boiling phenomenon caused by increasing heat inputs in subcooled water at high pressures is necessary to predict correctly a severe accident due to a power burst in a water-cooled nuclear reactor. Transient maximum heat fluxes, q max , on a 1.2 mm diameter horizontal cylinder in a pool of saturated and subcooled water for exponential heat inputs, q o e t/T , with periods, τ, ranging from about 2 ms to 20 s at pressures from atmospheric up to 2063 kPa for water subcoolings from 0 to about 80 K were measured to obtain the extended data base to investigate the effect of high subcoolings on steady-state and transient maximum heat fluxes, q max . Two main mechanisms of q max exist depending on the exponential periods at low subcoolings. One is due to the time lag of the hydrodynamic instability which starts at steady-state maximum heat flux on fully developed nucleate boiling (FDNB), and the other is due to the heterogenous spontaneous nucleations (HSN) in flooded cavities which coexist with vapor bubbles growing up from active cavities. The shortest period corresponding to the maximum q max for long period range belonging to the former mechanism becomes longer and the q max mechanism for long period range shifts to that due the HSN on FDNB with the increase of subcooling and pressure. The longest period corresponding to the minimum q max for the short period range belonging to the latter mechanism becomes shorter with the increase in saturated pressure. On the contrary, the longest period becomes longer with the increase in subcooling at high pressures. Correlations for steady-state and transient maximum heat fluxes were presented for a wide range of pressure and subcooling

Transient pool boiling heat transfer due to increasing heat inputs in subcooled water at high pressures

Energy Technology Data Exchange (ETDEWEB)

Fukuda, K. [Kobe Univ. of Mercantile Marine (Japan); Shiotsu, M.; Sakurai, A. [Kyoto Univ. (Japan)

1995-09-01

Understanding of transient boiling phenomenon caused by increasing heat inputs in subcooled water at high pressures is necessary to predict correctly a severe accident due to a power burst in a water-cooled nuclear reactor. Transient maximum heat fluxes, q{sub max}, on a 1.2 mm diameter horizontal cylinder in a pool of saturated and subcooled water for exponential heat inputs, q{sub o}e{sup t/T}, with periods, {tau}, ranging from about 2 ms to 20 s at pressures from atmospheric up to 2063 kPa for water subcoolings from 0 to about 80 K were measured to obtain the extended data base to investigate the effect of high subcoolings on steady-state and transient maximum heat fluxes, q{sub max}. Two main mechanisms of q{sub max} exist depending on the exponential periods at low subcoolings. One is due to the time lag of the hydrodynamic instability which starts at steady-state maximum heat flux on fully developed nucleate boiling (FDNB), and the other is due to the heterogenous spontaneous nucleations (HSN) in flooded cavities which coexist with vapor bubbles growing up from active cavities. The shortest period corresponding to the maximum q{sub max} for long period range belonging to the former mechanism becomes longer and the q{sub max}mechanism for long period range shifts to that due the HSN on FDNB with the increase of subcooling and pressure. The longest period corresponding to the minimum q{sub max} for the short period range belonging to the latter mechanism becomes shorter with the increase in saturated pressure. On the contrary, the longest period becomes longer with the increase in subcooling at high pressures. Correlations for steady-state and transient maximum heat fluxes were presented for a wide range of pressure and subcooling.

Body segment differences in surface area, skin temperature and 3D displacement and the estimation of heat balance during locomotion in hominins.

Science.gov (United States)

Cross, Alan; Collard, Mark; Nelson, Andrew

2008-06-18

The conventional method of estimating heat balance during locomotion in humans and other hominins treats the body as an undifferentiated mass. This is problematic because the segments of the body differ with respect to several variables that can affect thermoregulation. Here, we report a study that investigated the impact on heat balance during locomotion of inter-segment differences in three of these variables: surface area, skin temperature and rate of movement. The approach adopted in the study was to generate heat balance estimates with the conventional method and then compare them with heat balance estimates generated with a method that takes into account inter-segment differences in surface area, skin temperature and rate of movement. We reasoned that, if the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement affect heat balance during locomotion is correct, the estimates yielded by the two methods should be statistically significantly different. Anthropometric data were collected on seven adult male volunteers. The volunteers then walked on a treadmill at 1.2 m/s while 3D motion capture cameras recorded their movements. Next, the conventional and segmented methods were used to estimate the volunteers' heat balance while walking in four ambient temperatures. Lastly, the estimates produced with the two methods were compared with the paired t-test. The estimates of heat balance during locomotion yielded by the two methods are significantly different. Those yielded by the segmented method are significantly lower than those produced by the conventional method. Accordingly, the study supports the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement impact heat balance during locomotion. This has important implications not only for current understanding of heat balance during locomotion in hominins but also for how future research on this topic should be approached.

Body segment differences in surface area, skin temperature and 3D displacement and the estimation of heat balance during locomotion in hominins.

Directory of Open Access Journals (Sweden)

Alan Cross

Full Text Available The conventional method of estimating heat balance during locomotion in humans and other hominins treats the body as an undifferentiated mass. This is problematic because the segments of the body differ with respect to several variables that can affect thermoregulation. Here, we report a study that investigated the impact on heat balance during locomotion of inter-segment differences in three of these variables: surface area, skin temperature and rate of movement. The approach adopted in the study was to generate heat balance estimates with the conventional method and then compare them with heat balance estimates generated with a method that takes into account inter-segment differences in surface area, skin temperature and rate of movement. We reasoned that, if the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement affect heat balance during locomotion is correct, the estimates yielded by the two methods should be statistically significantly different. Anthropometric data were collected on seven adult male volunteers. The volunteers then walked on a treadmill at 1.2 m/s while 3D motion capture cameras recorded their movements. Next, the conventional and segmented methods were used to estimate the volunteers' heat balance while walking in four ambient temperatures. Lastly, the estimates produced with the two methods were compared with the paired t-test. The estimates of heat balance during locomotion yielded by the two methods are significantly different. Those yielded by the segmented method are significantly lower than those produced by the conventional method. Accordingly, the study supports the hypothesis that inter-segment differences in surface area, skin temperature and rate of movement impact heat balance during locomotion. This has important implications not only for current understanding of heat balance during locomotion in hominins but also for how future research on this topic should be

Natural convection in an adiabatic vertical channel due to a dissipated heat element

International Nuclear Information System (INIS)

Ramos, M.A.M.S.

1986-01-01

An experimental study was perfomed on natural convection heat transfer to air in a vertical channel due to an isothermal heated element attached in one of the walls of the channel. The heated element dissipates heat due to the Joule effect. To determine the heat transfer coefficient, it is necessary to evaluate the heat transferred to air by natural convenction alone. Hence, the heat lost by the element due to conduction and radiation is evaluated in order to correct the measured heat transfer. The natural-convenction heat transfer coefficient is a function of the following parameters: the temperature difference between the element and the ambient air, the position of the element in the channel, and the channel spacing. An optimal value of the channel spacing, when the heat transfer coefficient attains its maximum value, was observed for each of the temperature difference investigated. These maximum values may be up to 25% higher than the value for the case of infinite spacing. Comparisons are made with results available in the literature for similar configurations, and the values found in this work are higher. (author) [pt

Temperature distribution due to the heat generation in nuclear reactor shielding

International Nuclear Information System (INIS)

Torres, L.M.R.

1985-01-01

A study is performed for calculating nuclear heating due to the interaction of neutrons and gamma-rays with matter. Modifications were implemented in the ANISN and DOT 3.5 codes, that solve the transport equation using the discrete ordinate method, in one two-dimensions respectively, to include nuclear heating calculations in these codes. In order to determine the temperature distribution, using the finite difference method, a numerical model was developed for solving the heat conduction equation in one-dimension, in plane, cylindrical and spherical geometries, and in two-dimensions, X-Y and R-Z geometries. Based on these models, computer programs were developed for calculating the temperature distribution. Tests and applications of the implemented modifications were performed in problems of nuclear heating and temperature distribution due to radiation energy deposition in fission and fusion reactor shields. (Author) [pt

Nonlinear gain suppression in semiconductor lasers due to carrier heating

International Nuclear Information System (INIS)

Willatzen, M.; Uskov, A.; Moerk, J.; Olesen, H.; Tromborg, B.; Jauho, A.P.

1991-01-01

We present a simple model for carrier heating in semiconductor lasers, from which the temperature dynamics of the electron and hole distributions can be calculated. Analytical expressions for two new contributions to the nonlinear gain coefficient ε are derived, which reflect carrier heating due to stimulated emission and free carrier absorption. In typical cases, carrier heating and spectral holeburning are found to give comparable contributions to nonlinear gain suppression. The results are in good agreement with recent measurements on InGaAsP laser diodes. (orig.)

Effect of coating material on heat transfer and skin friction due to impinging jet onto a laser producedhole

Science.gov (United States)

Shuja, S. Z.; Yilbas, B. S.

2013-07-01

Jet impingement onto a two-layer structured hole in relation to laser drilling is investigated. The hole consists of a coating layer and a base material. The variations in the Nusselt number and the skin friction are predicted for various coating materials. The Reynolds stress turbulent model is incorporated to account for the turbulence effect of the jet flow and nitrogen is used as the working fluid. The study is extended to include two jet velocities emanating from the conical nozzle. It is found that coating material has significant effect on the Nusselt number variation along the hole wall. In addition, the skin friction varies considerably along the coating thickness in thehole.

Temporal evolutions of electron temperature and density of turbulently-heated tokamak plasmas in TRIAM-1

Energy Technology Data Exchange (ETDEWEB)

Hiraki, N; Nakamura, K; Nakamura, Y; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1981-04-01

The temporal evolution of the electron temperature and density are measured in a turbulent heating experiment in TRIAM-1. Skin-like profiles of the electron temperature and density are clearly observed. The anomality in the electrical resistivity of the plasma in this skin-layer is estimated, and the plasma heating in this skin-layer is regarded as being due to anomalous joule heating arising from this anomalous resistivity. The ratio of drift velocity to electron thermal velocity in the layer is also calculated, and it is shown that the conditions needed to make the current-driven ion-acoustic instability triggerable are satisfied.

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.

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.

Double skin façade: Modelling technique and influence of venetian blinds on the airflow and heat transfer

International Nuclear Information System (INIS)

Iyi, Draco; Hasan, Reaz; Penlington, Roger; Underwood, Chris

2014-01-01

The demand to reduce building cooling load and annual energy consumption can be optimised with the use of Double Skin Facade (DSF). Computational Fluid Dynamics (CFD) methods are frequently used for the analysis of heat transfer through DSF. However, considerable uncertainty exists regarding few key parameters, such as modelling strategies and the solar heat transmitted to the indoor space as a function of the blind tilt angles and positioning within the façade channel. In this paper we have investigated four modelling strategies and the influence of blind tilt angle and their proximity to the façade walls. The DSF system used in this investigation is equipped with venetian blinds and facades that absorb and reflect the incident solar radiation and transfer the direct solar heat gain into the building. A finite volume discretization method with the SIMPLE solution algorithm of the velocity-pressure coupling involving the low-turbulence k–ε model is used. A ray-traced solar model is coupled with long wave radiation model to solve the complete solar and radiation fields along with convection and conduction fields. On the modelling strategies, three dimensional domains were cast over three computational zones; external zone with solar radiation entering the outer skin of glass; buoyancy-driven air cavity zone with convection and transmitted solar radiation; and an internal zone. Also investigated is the thermal behaviour of the DSF due to the blind tilt angles (30°, 45°, 60°, and 75°) and its position from the facade walls (104 mm, 195 mm, 287 mm and 379 mm). Validations of the results are based on experimental data from the literature and the predicted trends compared very well with the experimental measurements. The heat gain due to direct solar radiation and convection through the facades to the internal space are presented. Comparative analysis of the four modelling strategies shows little variation of the results. The implication is a reduction in

Discomfort due to skin humidity with different fabric textures and materials

DEFF Research Database (Denmark)

Toftum, Jørn; Rasmussen, Leif Winsnes; Mackeprang, Jørgen

2000-01-01

This study investigated the possible effects of material and texture of the inner clothing layer on human comfort. A highly hygroscopic material (cotton) and a material of low hygroscopicity (polyester) were tested. Also, it was tested whether fabric texture (knitted/woven) influenced the perceived...... due to humid skin or clothing for persons engaged in office work, wearing woven or knitted inner layers made of polyester or cotton. The model allows upper limits for air humidity to be determined for indoor environments. In the comfort zone of temperatures, the model predicts only a moderate...

A real-time heat strain risk classifier using heart rate and skin temperature

International Nuclear Information System (INIS)

Buller, Mark J; Latzka, William A; Yokota, Miyo; Tharion, William J; Moran, Daniel S

2008-01-01

Heat injury is a real concern to workers engaged in physically demanding tasks in high heat strain environments. Several real-time physiological monitoring systems exist that can provide indices of heat strain, e.g. physiological strain index (PSI), and provide alerts to medical personnel. However, these systems depend on core temperature measurement using expensive, ingestible thermometer pills. Seeking a better solution, we suggest the use of a model which can identify the probability that individuals are 'at risk' from heat injury using non-invasive measures. The intent is for the system to identify individuals who need monitoring more closely or who should apply heat strain mitigation strategies. We generated a model that can identify 'at risk' (PSI ≥ 7.5) workers from measures of heart rate and chest skin temperature. The model was built using data from six previously published exercise studies in which some subjects wore chemical protective equipment. The model has an overall classification error rate of 10% with one false negative error (2.7%), and outperforms an earlier model and a least squares regression model with classification errors of 21% and 14%, respectively. Additionally, the model allows the classification criteria to be adjusted based on the task and acceptable level of risk. We conclude that the model could be a valuable part of a multi-faceted heat strain management system. (note)

Jet impinging onto a laser drilled tapered hole: Influence of tapper location on heat transfer and skin friction at hole surface

Science.gov (United States)

Shuja, S. Z.; Yilbas, B. S.

2013-02-01

Jet emerging from a conical nozzle and impinging onto a tapered hole in relation to laser drilling is investigated and the influence taper location on the heat transfer and skin friction at the hole wall surface is examined. The study is extended to include four different gases as working fluid. The Reynolds stress model is incorporated to account for the turbulence effect in the flow field. The hole wall surface temperature is kept at 1500 K to resemble the laser drilled hole. It is found that the location of tapering in the hole influences the heat transfer rates and skin friction at the hole wall surface. The maximum skin friction coefficient increases for taper location of 0.25 H, where H is the thickness of the workpiece, while Nusselt number is higher in the hole for taper location of 0.75 H.

Skin vasomotor hemiparesis followed by overactivity: characteristic thermography findings in a patient with Horner syndrome due to spinal cord infarction.

Science.gov (United States)

Kobayashi, Makoto

2016-04-01

We present a 21-year-old female with Horner syndrome due to spinal cord infarction. In this patient, infrared thermography revealed a hemibody skin temperature increase followed by excessive focal decreases, indicating skin vasomotor hemiparesis and overactivity.

Experimental study of heat transfer enhancement due to the surface vibrations in a flexible double pipe heat exchanger

Science.gov (United States)

Hosseinian, A.; Meghdadi Isfahani, A. H.

2018-04-01

In this study, the heat transfer enhancement due to the surface vibration for a double pipe heat exchanger, made of PVDF, is investigated. In order to create forced vibrations (3-9 m/s2, 100 Hz) on the outer surface of the heat exchanger electro-dynamic vibrators are used. Experiments were performed at inner Reynolds numbers ranging from 2533 to 9960. The effects of volume flow rate and temperature on heat transfer performance are evaluated. Results demonstrated that heat transfer coefficient increases by increasing vibration level and mass flow rate. The most increase in heat transfer coefficient is 97% which is obtained for the highest vibration level (9 m/s2) in the experiment range.

Simulation of stretch forming with intermediate heat treatments of aircraft skins - A physically based modeling approach

NARCIS (Netherlands)

Kurukuri, S.; Miroux, Alexis; Wisselink, H.H.; van den Boogaard, Antonius H.

2011-01-01

In the aerospace industry stretch forming is often used to produce skin parts. During stretch forming a sheet is clamped at two sides and stretched over a die, such that the sheet gets the shape of the die. However for complex shapes it is necessary to use expensive intermediate heat-treatments in

Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans.

Science.gov (United States)

Wingo, Jonathan E; Low, David A; Keller, David M; Brothers, R Matthew; Shibasaki, Manabu; Crandall, Craig G

2010-11-01

Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ~1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.

Numerical modelling of transient heat and moisture transport in protective clothing

International Nuclear Information System (INIS)

Łapka, P; Furmański, P; Wisniewski, T S

2016-01-01

The paper presents a complex model of heat and mass transfer in a multi-layer protective clothing exposed to a flash fire and interacting with the human skin. The clothing was made of porous fabric layers separated by air gaps. The fabrics contained bound water in the fibres and moist air in the pores. The moist air was also present in the gaps between fabric layers or internal fabric layer and the skin. Three skin sublayers were considered. The model accounted for coupled heat transfer by conduction, thermal radiation and associated with diffusion of water vapour in the clothing layers and air gaps. Heat exchange due to phase transition of the bound water were also included in the model. Complex thermal and mass transfer conditions at internal or external boundaries between fabric layers and air gaps as well as air gap and skin were assumed. Special attention was paid to modelling of thermal radiation which was coming from the fire, penetrated through protective clothing and absorbed by the skin. For the first time non-grey properties as well as optical phenomena at internal or external boundaries between fabric layers and air gaps as well as air gap and skin were accounted for. A series of numerical simulations were carried out and the risk of heat injures was estimated. (paper)

Numerical study of unsteady MHD oblique stagnation point flow and heat transfer due to an oscillating stream

Science.gov (United States)

Javed, T.; Ghaffari, A.; Ahmad, H.

2016-05-01

The unsteady stagnation point flow impinging obliquely on a flat plate in presence of a uniform applied magnetic field due to an oscillating stream has been studied. The governing partial differential equations are transformed into dimensionless form and the stream function is expressed in terms of Hiemenz and tangential components. The dimensionless partial differential equations are solved numerically by using well-known implicit finite difference scheme named as Keller-box method. The obtained results are compared with those available in the literature. It is observed that the results are in excellent agreement with the previous studies. The effects of pertinent parameters involved in the problem namely magnetic parameter, Prandtl number and impinging angle on flow and heat transfer characteristics are illustrated through graphs. It is observed that the influence of magnetic field strength increases the fluid velocity and by the increase of obliqueness parameter, the skin friction increases.

Significant skin burns may occur with the use of a water balloon in HIFU treatment

Science.gov (United States)

Ritchie, Robert; Collin, Jamie; Wu, Feng; Coussios, Constantin; Leslie, Tom; Cranston, David

2012-10-01

HIFU is a minimally-invasive therapy suitable for treating selected intra-abdominal tumors. Treatment is safe although skin burns may occur due to pre-focal heating. HIFU treatment of a renal transplant tumor located in the left lower abdomen was undertaken in our centre. Treatment was performed prone, requiring displacement of the abdominal wall away from the treatment field using a water balloon, constructed of natural rubber latex and filled with degassed water. Intra-operatively, ultrasound imaging and physical examination of the skin directly over the focal region was normal. Immediately post-operative, a full-thickness skin burn was evident at the periphery of the balloon location, outside the expected HIFU path. Three possibilities may account for this complication. Firstly, the water balloon may have acted as a lens, focusing the HIFU to a neo-focus off axis. Secondly, air bubbles may have been entrapped between the balloon and the skin, causing heating at the interface. Finally, heating of the isolated water within the balloon may have been sufficient to cause burning. In this case, the placement of a water balloon caused a significant skin burn. Care should be taken in their use as burns, situated off axis, may occur even if the overlying skin appears normal.

Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures in residential buildings

International Nuclear Information System (INIS)

Åberg, M.; Henning, D.

2011-01-01

The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. In Sweden, co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linköping is calculated. The impact of HD reduction on heat and electricity production in the Linköping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production. The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO 2 emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO 2 emissions in the analysed DH system. - Highlights: ► A MODEST optimisation model of the Linköping district heating system is used. ► The impact of heat demand reduction on heat and electricity production is examined. ► Model results show that heat demand reductions decrease heat-only production. ► Local and global CO 2 emissions are reduced. ► The system electricity-to-heat output increases for reduced heat demand up to 30%.

Beam heat load due to geometrical and resistive wall impedance in COLDDIAG

Science.gov (United States)

Casalbuoni, S.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Spataro, B.

2012-11-01

One of the still open issues for the development of superconductive insertion devices is the understanding of the heat intake from the electron beam. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the underlying mechanisms, a cold vacuum chamber for diagnostics (COLDDIAG) was built. It is equipped with the following instrumentation: retarding field analyzers to measure the electron flux, temperature sensors to measure the beam heat load, pressure gauges, and mass spectrometers to measure the gas content. Possible beam heat load sources are: synchrotron radiation, wakefield effects due to geometrical and resistive wall impedance and electron/ion bombardment. The flexibility of the engineering design will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG was first installed in the Diamond Light Source (DLS) in 2011. Due to a mechanical failure of the thermal transition of the cold liner, the cryostat had to be removed after one week of operation. After having implemented design changes in the thermal liner transition, COLDDIAG has been reinstalled in the DLS at the end of August 2012. In order to understand the beam heat load mechanism it is important to compare the measured COLDDIAG parameters with theoretical expectations. In this paper we report on the analytical and numerical computation of the COLDDIAG beam heat load due to coupling impedances deriving from unavoidable step transitions, ports used for pumping and diagnostics, surface roughness, and resistive wall. The results might have an important impact on future technological solutions to be applied to cold bore devices.

Increased dose near the skin due to electromagnetic surface beacon transponder.

Science.gov (United States)

Ahn, Kang-Hyun; Manger, Ryan; Halpern, Howard J; Aydogan, Bulent

2015-05-08

The purpose of this study was to evaluate the increased dose near the skin from an electromagnetic surface beacon transponder, which is used for localization and tracking organ motion. The bolus effect due to the copper coil surface beacon was evaluated with radiographic film measurements and Monte Carlo simulations. Various beam incidence angles were evaluated for both 6 MV and 18 MV experimentally. We performed simulations using a general-purpose Monte Carlo code MCNPX (Monte Carlo N-Particle) to supplement the experimental data. We modeled the surface beacon geometry using the actual mass of the glass vial and copper coil placed in its L-shaped polyethylene terephthalate tubing casing. Film dosimetry measured factors of 2.2 and 3.0 enhancement in the surface dose for normally incident 6 MV and 18 MV beams, respectively. Although surface dose further increased with incidence angle, the relative contribution from the bolus effect was reduced at the oblique incidence. The enhancement factors were 1.5 and 1.8 for 6 MV and 18 MV, respectively, at an incidence angle of 60°. Monte Carlo simulation confirmed the experimental results and indicated that the epidermal skin dose can reach approximately 50% of the dose at dmax at normal incidence. The overall effect could be acceptable considering the skin dose enhancement is confined to a small area (~ 1 cm2), and can be further reduced by using an opposite beam technique. Further clinical studies are justified in order to study the dosimetric benefit versus possible cosmetic effects of the surface beacon. One such clinical situation would be intact breast radiation therapy, especially large-breasted women.

On the possibility of the patient's skin overheating during low-intensive phototherapy

Science.gov (United States)

Kokodii, Mykola G.; Korobov, Anatoliy M.; Timaniyk, Vladimir A.; Titova, Natalia V.; Burlibay, Aron; Omiotek, Zbigniew; Szatkowska, Małgorzata; Luganskaya, Saule

2017-08-01

This paper proposes a simple mathematical model of heating process of the human skin and adjacent inner layers with the LED radiation used in the prevention and treatment devices for various diseases. The problem takes into account the heat removal by blood flow to the vessels. It is shown that abnormal blood flow due to the compression of tissue can lead to severe heating of the body and its burn. This may result even from using small LEDs of 2,5-30 mW.

Dermatoses due to Indian cultural practices.

Science.gov (United States)

Gupta, Divya; Thappa, Devinder Mohan

2015-01-01

A wide prevalence of socio-religious and cultural practices in the Asian subcontinent often leads to multitude of skin diseases which may be missed by the dermatologists because of a lack of awareness. 'Henna' use causes IgE-mediated hypersensitivity reactions and contact dermatitis. 'Kumkum' application can result in pigmented contact dermatitis and lichen planus pigmentosus. Sticker 'bindis' and 'alta' induce contact leukoderma. Irritant and allergic contact dermatitis occurs after playing with 'Holi' colors. Threading and drawstring dermatitis lead to koebnerization of pre-existing dermatoses, infections and even squamous cell carcinoma of skin. Mild irritant reactions and contact sensitization occur secondary to balm and hair oil use. 'Mudichood' represents the comedogenic effect of hair oils combined with occlusion and humidity. Aromatherapy oils can cause contact dermatitis and photosensitive reactions. Heavy metal and steroid toxicity along with severe cutaneous adverse effects like erythroderma can occur as a consequent to the use of alternative medicines. Squamous cell carcinoma due to chronic heat exposure from the heating device "kangri" is seen in Kashmiris. Prayer nodules in Muslims and traction alopecia in Sikhs illustrate how religious practices can negatively affect the skin. With increasing globalization and migration, the practice of indigenous customs and traditions is no longer limited to regional territories, making it imperative for the dermatologists to be acquainted with the cutaneous side effects they can cause.

Measuring skin necrosis in a randomised controlled feasibility trial of heat preconditioning on wound healing after reconstructive breast surgery: study protocol and statistical analysis plan for the PREHEAT trial.

Science.gov (United States)

Cro, Suzie; Mehta, Saahil; Farhadi, Jian; Coomber, Billie; Cornelius, Victoria

2018-01-01

Essential strategies are needed to help reduce the number of post-operative complications and associated costs for breast cancer patients undergoing reconstructive breast surgery. Evidence suggests that local heat preconditioning could help improve the provision of this procedure by reducing skin necrosis. Before testing the effectiveness of heat preconditioning in a definitive randomised controlled trial (RCT), we must first establish the best way to measure skin necrosis and estimate the event rate using this definition. PREHEAT is a single-blind randomised controlled feasibility trial comparing local heat preconditioning, using a hot water bottle, against standard care on skin necrosis among breast cancer patients undergoing reconstructive breast surgery. The primary objective of this study is to determine the best way to measure skin necrosis and to estimate the event rate using this definition in each trial arm. Secondary feasibility objectives include estimating recruitment and 30 day follow-up retention rates, levels of compliance with the heating protocol, length of stay in hospital and the rates of surgical versus conservative management of skin necrosis. The information from these objectives will inform the design of a larger definitive effectiveness and cost-effectiveness RCT. This article describes the PREHEAT trial protocol and detailed statistical analysis plan, which includes the pre-specified criteria and process for establishing the best way to measure necrosis. This study will provide the evidence needed to establish the best way to measure skin necrosis, to use as the primary outcome in a future RCT to definitively test the effectiveness of local heat preconditioning. The pre-specified statistical analysis plan, developed prior to unblinded data extraction, sets out the analysis strategy and a comparative framework to support a committee evaluation of skin necrosis measurements. It will increase the transparency of the data analysis for the

Nonlinear behavior of micro bubbles under ultrasound due to heat transfer

International Nuclear Information System (INIS)

Lim, Chan Soo; Kwak, Ho Young; Kim, Jeong Eun; Lee, Jae Young

2009-01-01

We investigated the nonlinear behavior of a microbubble under ultrasound, taking into account the heat transfer inside the bubble and through the bubble wall. The polytropic relation, which has been used for the process of pressure change depending on the volume variation of ideal gases, cannot properly treat heat transfer involving the oscillating bubble under ultrasound. In this study, a set of solutions of the Navier-Stokes equations for the gas inside the bubble along with an analytical treatment of the Navier-Stokes equations for the liquid adjacent to the bubble wall was used to treat properly the heat transfer process for the oscillating bubble under ultrasound. Entropy generation due to finite heat transfer, which induces the lost work during bubble evolution, reduces the collapsing process and considerably affects the nonlinear behavior of the bubble

Postponement of incipient collapse due to work-induced heat stress by limited cooling

Science.gov (United States)

Blockley, W. V.

1973-01-01

Four subjects completed five treadmill training sessions under comfortable to cool conditions and were calibrated to find an optimum combination of speed and grade on the treadmill which would produce a metabolic rate of 2000 Btu-hr. Dressed in an Apollo liquid cooling garment, each man underwent a total of four experiments in which the rate of heat extraction from the liquid cooling garment was adjusted to an amount which would cause a storage within the body of 1000 Btu/hr. Physiological measurements included skin temperature at 9 locations, rectal and ear canal probes, and heart rate. The increases in tolerance time for the various subjects and the various methods of emergency cooling, ranged from a low of six minutes to a high of 48 minutes, or from 8 to 102% of the baseline tolerance times. The largest gains were achieved in a subject whose tolerance endpoint was atypical, and whose baseline heat tolerance was unsually low.

Skin temperature during sunbathing--relevance for skin cancer

DEFF Research Database (Denmark)

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

2014-01-01

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

Degradation of the performance of microchannel heat exchangers due to flow maldistribution

DEFF Research Database (Denmark)

Nielsen, Kaspar Kirstein; Engelbrecht, Kurt; Christensen, Dennis

2012-01-01

The effect of flow maldistribution on the performance of microchannel parallel plate heat exchangers is investigated using an established single blow numerical model and cyclic steady-state regenerator experiments. It is found that as the variation of the individual channel thickness...... in a particular stack (heat exchanger) increases the actual performance of the heat exchanger decreases significantly, deviating from the expected nominal performance. We show that this is due to both the varying fluid flow velocities in each individual channel and the thermal cross talk between the channels...

Unsteady mixed convection of a micropolar fluid past a circular cylinder due to time-dependent free stream velocity and temperature

Directory of Open Access Journals (Sweden)

Nepal C. Roy

2016-06-01

Full Text Available Unsteady mixed convection boundary-layer flow of an electrically conducting micropolar fluid past a circular cylinder is investigated taking into account the effect of thermal radiation and heat generation or absorption. The reduced non-similar boundary-layer equations are solved using the finite difference method. It is found that the magnitude of the friction factor and the couple stress significantly increases due to the increase of the mixed convection parameter, the conduction-radiation parameter, the surface temperature parameter, the heat absorption parameter and the frequency parameter. However the magnitude of the heat transfer rate decreases with these parameters. The converse characteristics are observed for the Prandtl number. The magnitude of the couple stress and the heat transfer rate is seen to decrease whereas the magnitude of the skin factor increases with increasing the vortex viscosity parameter. The magnetic field parameter reduces the skin factor, couple stress and heat transfer rate. The amplitude of oscillation of the transient skin factor and couple stress gradually increases owing to an increase of $\\xi$. But the transient heat transfer rate is found to be oscillating with almost the same amplitude for any value of $\\xi$. The amplitude of oscillation of the transient skin factor and couple stress increases with an increase of $S$ and $\\xi$ while the amplitude of the transient heat transfer rate increases with increasing Pr and $S$.

Small scale changes of geochemistry and flow field due to transient heat storage in aquifers

Science.gov (United States)

Bauer, S.; Boockmeyer, A.; Li, D.; Beyer, C.

2013-12-01

Heat exchangers in the subsurface are increasingly installed for transient heat storage due to the need of heating or cooling of buildings as well as the interim storage of heat to compensate for the temporally fluctuating energy production by wind or solar energy. For heat storage to be efficient, high temperatures must be achieved in the subsurface. Significant temporal changes of the soil and groundwater temperatures however effect both the local flow field by temperature dependent fluid parameters as well as reactive mass transport through temperature dependent diffusion coefficients, geochemical reaction rates and mineral equilibria. As the use of heat storage will be concentrated in urban areas, the use of the subsurface for (drinking) water supply and heat storage will typically coincide and a reliable prognosis of the processes occurring is needed. In the present work, the effects of a temporal variation of the groundwater temperature, as induced by a local heat exchanger introduced into a groundwater aquifer, are studied. For this purpose, the coupled non-isothermal groundwater flow, heat transport and reactive mass transport is simulated in the near filed of such a heat exchanger. By explicitly discretizing and incorporating the borehole, the borehole cementation and the heat exchanger tubes, a realistic geometrical and process representation is obtained. The numerical simulation code OpenGeoSys is used in this work, which incorporates the required processes of coupled groundwater flow, heat and mass transport as well as temperature dependent geochemistry. Due to the use of a Finite Element Method, a close representation of the geometric effects can be achieved. Synthetic scenario simulations for typical settings of salt water formations in northern Germany are used to investigate the geochemical effects arising from a high temperature heat storage by quantifying changes in groundwater chemistry and overall reaction rates. This work presents the

Contamination of a church ceiling due to the burning of candles in combination with floor heating

NARCIS (Netherlands)

Schellen, H.L.; Deelman, J.; Aarle, van M.A.P.

2005-01-01

An air heating system originally heated St. Martinus’ church in Weert. Together with a large restoration in 1984 a floor heating system replaced this heating system. After this major renovation a number of problems arose: due to the floor heating system and massive granite floor the church could

Contamination of a church ceiling due to the burning of candles in combination with floor heating

NARCIS (Netherlands)

Schellen, H.L.; Aarle, van M.A.P.

2005-01-01

An air heating system originally heated St. Martin's church in Weert. Together with an extensive restoration in 1984 a floor heating system replaced this heating system. After this major renovation a number of problems arose: due to the floor heating System and massive granite floor the church could

Dermatoses due to indian cultural practices

Directory of Open Access Journals (Sweden)

Divya Gupta

2015-01-01

Full Text Available A wide prevalence of socio-religious and cultural practices in the Asian subcontinent often leads to multitude of skin diseases which may be missed by the dermatologists because of a lack of awareness. ′Henna′ use causes IgE-mediated hypersensitivity reactions and contact dermatitis. ′Kumkum′ application can result in pigmented contact dermatitis and lichen planus pigmentosus. Sticker ′bindis′ and ′alta′ induce contact leukoderma. Irritant and allergic contact dermatitis occurs after playing with ′Holi′ colors. Threading and drawstring dermatitis lead to koebnerization of pre-existing dermatoses, infections and even squamous cell carcinoma of skin. Mild irritant reactions and contact sensitization occur secondary to balm and hair oil use. ′Mudichood′ represents the comedogenic effect of hair oils combined with occlusion and humidity. Aromatherapy oils can cause contact dermatitis and photosensitive reactions. Heavy metal and steroid toxicity along with severe cutaneous adverse effects like erythroderma can occur as a consequent to the use of alternative medicines. Squamous cell carcinoma due to chronic heat exposure from the heating device "kangri" is seen in Kashmiris. Prayer nodules in Muslims and traction alopecia in Sikhs illustrate how religious practices can negatively affect the skin. With increasing globalization and migration, the practice of indigenous customs and traditions is no longer limited to regional territories, making it imperative for the dermatologists to be acquainted with the cutaneous side effects they can cause.

Sprayed skin turbine component

Science.gov (United States)

Allen, David B

2013-06-04

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

Development of a Skin Burn Predictive Model adapted to Laser Irradiation

Science.gov (United States)

Sonneck-Museux, N.; Scheer, E.; Perez, L.; Agay, D.; Autrique, L.

2016-12-01

Laser technology is increasingly used, and it is crucial for both safety and medical reasons that the impact of laser irradiation on human skin can be accurately predicted. This study is mainly focused on laser-skin interactions and potential lesions (burns). A mathematical model dedicated to heat transfers in skin exposed to infrared laser radiations has been developed. The model is validated by studying heat transfers in human skin and simultaneously performing experimentations an animal model (pig). For all experimental tests, pig's skin surface temperature is recorded. Three laser wavelengths have been tested: 808 nm, 1940 nm and 10 600 nm. The first is a diode laser producing radiation absorbed deep within the skin. The second wavelength has a more superficial effect. For the third wavelength, skin is an opaque material. The validity of the developed models is verified by comparison with experimental results (in vivo tests) and the results of previous studies reported in the literature. The comparison shows that the models accurately predict the burn degree caused by laser radiation over a wide range of conditions. The results show that the important parameter for burn prediction is the extinction coefficient. For the 1940 nm wavelength especially, significant differences between modeling results and literature have been observed, mainly due to this coefficient's value. This new model can be used as a predictive tool in order to estimate the amount of injury induced by several types (couple power-time) of laser aggressions on the arm, the face and on the palm of the hand.

Maxwell-Cattaneo Heat Convection and Thermal Stresses Responses of a Semi-Infinite Medium to High-Speed Laser Heating due to High Speed Laser Heating

Directory of Open Access Journals (Sweden)

Abdallah I. A.

2009-07-01

Full Text Available Based on Maxwell-Cattaneo convection equation, the thermoelasticity problem is in- vestigated in this paper. The analytic solution of a boundary value problem for a semi- infinite medium with traction free surface heated by a high-speed laser-pulses have Dirac temporal profile is solved. The temperature, the displacement and the stresses distributions are obtained analytically using the Laplace transformation, and discussed at small time duration of the laser pulses. A numerical study for Cu as a target is performed. The results are presented graphically. The obtained results indicate that the small time duration of the laser pulses has no e ect on the finite velocity of the heat con- ductivity, but the behavior of the stress and the displacement distribution are affected due to the pulsed heating process and due to the structure of the governing equations.

Ion heating due to rotation and collision in magnetized plasma

International Nuclear Information System (INIS)

Anderegg, F.; Stern, R.A.; Skiff, F.; Hammel, B.A.; Tran, M.Q.; Paris, P.J.; Kohler, P.

1986-01-01

The E x B rotation and associated collisional ion heating of noble-gas magnetized plasmas are investigated with high resolution by means of laser-induced fluorescence and electrical probes. Plasma rotation results from a radial potential gradient which can be controlled by biasing of the discharge electrodes. The time and space evolution of the potential, the rotation velocity v/sub t//sub h//sub e//sub t//sub a/, and the ion perpendicular temperature indicate that heating is due to the randomization of v/sub t//sub h//sub e//sub t//sub a/ by ion-neutral collisions, and leads to temperature increases as high as a factor of 50 over initial values

On the influence of electron heat transport on generation of the third harmonic of laser radiation in a dense plasma skin layer

International Nuclear Information System (INIS)

Isakov, Vladimir A; Kanavin, Andrey P; Uryupin, Sergey A

2005-01-01

The flux density is determined for radiation emitted by a plasma at the tripled frequency of an ultrashort laser pulse, which produces weak high-frequency modulations of the electron temperature in the plasma skin layer. It is shown that heat removal from the skin layer can reduce high-frequency temperature modulations and decrease the nonlinear plasma response. The optimum conditions for the third harmonic generation are found. (interaction of laser radiation with matter. laser plasma)

Skin granulomas due to Mycobacterium gordonae.

Science.gov (United States)

Gengoux, P; Portaels, F; Lachapelle, J M; Minnikin, D E; Tennstedt, D; Tamigneau, P

1987-04-01

A 38-year-old woman presented with small, ulcerated, red or bluish nodules on the right hand, clinically resembling mycobacterial granulomas; these appeared a few months after a bite by a rat, while the patient was collecting frogs in a pond in the Belgian Ardennes. The histopathologic picture was compatible with a diagnosis of mycobacterial infection and rare acid-fast bacilli could be found. Repeated bacteriologic investigations were performed and these led to the identification of a strain displaying characteristics of Mycobacterium gordonae. The skin condition responded well to rifampicin (300 mg/day) within 6 months.

Skin color independent assessment of aging using skin autofluorescence

NARCIS (Netherlands)

Koetsier, M.; Nur, Erfan; Chunmao, Han; Lutgers, Helen L.; Links, Thera P.; Smit, Andries J.; Rakhorst, Gerhard; Graaff, Reindert

2010-01-01

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

Skin color independent assessment of aging using skin autofluorescence

NARCIS (Netherlands)

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

2010-01-01

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

Synergistic skin heat shock protein expression in response to combined laser treatment with a diode laser and ablative fractional lasers.

Science.gov (United States)

Paasch, Uwe; Sonja, Grunewald; Haedersdal, Merete

2014-06-01

Diode laser-based skin heating has been shown to minimise scars by interfering with wound healing responses through the induction of heat shock proteins (HSP). HSP are also induced after ablative fractional laser (AFXL) wound healing. AFXL itself is highly recommended for scar treatment. Therefore, the sequential combination of both modalities may produce superior outcomes. The aim of this study was to examine the pretreatment effects of a diode laser before AFXL on wound healing responses in terms of HSP up-regulation in an in vitro model. Immediate responses and responses on days 1, 3 or 6 post-procedure were studied in an in vitro porcine skin model (n = 240). Untreated samples served as control. Immunohistochemical investigation (Hsp70) was performed in all untreated controls, diode laser-, AFXL-, and in diode laser + AFXL-treated samples. Hsp70 was shown to be up-regulated by all interventions between days 1 and 6 after interventions. The largest effect was caused by the combination of a diode laser and an AFXL procedure. Diode laser exposure induces a skin HSP response that can be further enhanced by sequential AFXL treatment. Clinical studies are necessary to investigate the dose response of HSP on scar formation and refine suitable laser exposure settings.

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

Effects on heat transfer of multiphase magnetic fluid due to circular magnetic field over a stretching surface with heat source/sink and thermal radiation

Directory of Open Access Journals (Sweden)

A. Zeeshan

Full Text Available The purpose of the current article is to explore the boundary layer heat transport flow of multiphase magnetic fluid with solid impurities suspended homogeneously past a stretching sheet under the impact of circular magnetic field. Thermal radiation effects are also taken in account. The equations describing the flow of dust particles in fluid along with point dipole are modelled by employing conservation laws of mass, momentum and energy, which are then converted into non-linear coupled differential equations by mean of similarity approach. The transformed ODE’s are tackled numerically with the help of efficient Runga-Kutta method. The influence of ferromagnetic interaction parameter, viscous dissipation, fluid-particle interaction parameter, Eckert number, Prandtl number, thermal radiation parameter and number of dust particles, heat production or absorption parameter with the two thermal process namely, prescribed heat flux (PHF or prescribed surface temperature (PST are observed on temperature and velocity profiles. The value of skin-friction coefficient and Nusselt number are calculated for numerous physical parameters. Present results are correlated with available for a limited case and an excellent agreement is found. Keywords: Ferromagnetic interaction parameter, Dusty magnetic fluid, stretching sheet, Magnetic dipole, Heat source/sink, Thermal radiation

Chromospheric Heating due to Cancellation of Quiet Sun Internetwork Fields

Science.gov (United States)

Gošić, M.; de la Cruz Rodríguez, J.; De Pontieu, B.; Bellot Rubio, L. R.; Carlsson, M.; Esteban Pozuelo, S.; Ortiz, A.; Polito, V.

2018-04-01

The heating of the solar chromosphere remains one of the most important questions in solar physics. Our current understanding is that small-scale internetwork (IN) magnetic fields play an important role as a heating agent. Indeed, cancellations of IN magnetic elements in the photosphere can produce transient brightenings in the chromosphere and transition region. These bright structures might be the signature of energy release and plasma heating, probably driven by the magnetic reconnection of IN field lines. Although single events are not expected to release large amounts of energy, their global contribution to the chromosphere may be significant due to their ubiquitous presence in quiet Sun regions. In this paper, we study cancellations of IN elements and analyze their impact on the energetics and dynamics of the quiet Sun atmosphere. We use high-resolution, multiwavelength, coordinated observations obtained with the Interface Region Imaging Spectrograph and the Swedish 1 m Solar Telescope (SST) to identify cancellations of IN magnetic flux patches and follow their evolution. We find that, on average, these events live for ∼3 minutes in the photosphere and ∼12 minutes in the chromosphere and/or transition region. Employing multi-line inversions of the Mg II h and k lines, we show that cancellations produce clear signatures of heating in the upper atmospheric layers. However, at the resolution and sensitivity accessible to the SST, their number density still seems to be one order of magnitude too low to explain the global chromospheric heating.

Heat Loads Due To Small Penetrations In Multilayer Insulation Blankets

Science.gov (United States)

Johnson, W. L.; Heckle, K. W.; E Fesmire, J.

2017-12-01

The main penetrations (supports and piping) through multilayer insulation systems for cryogenic tanks have been previously addressed by heat flow measurements. Smaller penetrations due to fasteners and attachments are now experimentally investigated. The use of small pins or plastic garment tag fasteners to ease the handling and construction of multilayer insulation (MLI) blankets goes back many years. While it has long been understood that penetrations and other discontinuities degrade the performance of the MLI blanket, quantification of this degradation has generally been lumped into gross performance multipliers (often called degradation factors or scale factors). Small penetrations contribute both solid conduction and radiation heat transfer paths through the blanket. The conduction is down the stem of the structural element itself while the radiation is through the hole formed during installation of the pin or fastener. Analytical models were developed in conjunction with MLI perforation theory and Fourier’s Law. Results of the analytical models are compared to experimental testing performed on a 10 layer MLI blanket with approximately 50 small plastic pins penetrating the test specimen. The pins were installed at ∼76-mm spacing inches in both directions to minimize the compounding of thermal effects due to localized compression or lateral heat transfer. The testing was performed using a liquid nitrogen boil-off calorimeter (Cryostat-100) with the standard boundary temperatures of 293 K and 78 K. Results show that the added radiation through the holes is much more significant than the conduction down the fastener. The results are shown to be in agreement with radiation theory for perforated films.

Ultrastructural observations of chemical peeling for skin rejuvenation (ultrastructural changes of the skin due to chemical peeling).

Science.gov (United States)

Omi, Tokuya; Sato, Shigeru; Numano, Kayoko; Kawana, Seiji

2010-02-01

Chemical peeling of the skin is commonly used as a means to treat photoaging, but the mechanism underlying its efficacy has not yet been fully clarified. We recently conducted chemical peeling of the skin with glycolic acid and lactic acid and observed it at the ultrastructural level. No changes in the horny layer or the upper epidermal layer were observed but there was dissociation and vacuolation between the basal cells and increases in vimentin filaments within fibroblasts and endothelial cells were seen. These findings suggest that chemical peeling of the skin with this type of agent directly induces collagen formation within the dermis and thus directly stimulates remodeling of the dermis.

How do Greenhouse Gases Warm the Ocean? Investigation of the Response of the Ocean Thermal Skin Layer to Air-Sea Surface Heat Fluxes.

Science.gov (United States)

Wong, E.; Minnett, P. J.

2016-12-01

There is much evidence that the ocean is heating due to an increase in concentrations of greenhouse gases (GHG) in the atmosphere from human activities. GHGs absorbs infrared (IR) radiation and re-emits the radiation back to the ocean's surface which is subsequently absorbed resulting in a rise in the ocean heat content. However, the incoming longwave radiation, LWin, is absorbed within the top micrometers of the ocean's surface, where the thermal skin layer (TSL) exists and does not directly heat the upper few meters of the ocean. We are therefore motivated to investigate the physical mechanism between the absorption of IR 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 TSL, which is directly influenced by the absorption and emission of IR radiation, the heat flow through the TSL adjusts to maintain the surface heat loss, and thus modulates the upper ocean heat content. This hypothesis is investigated through utilizing clouds to represent an increase in LWin and analyzing retrieved TSL vertical profiles from a shipboard IR spectrometer from two research cruises. The data is limited to night-time, no precipitation and low winds of heat from the absorption of the cloud infrared irradiance back into the atmosphere through processes such as evaporation. Instead, we observe the surplus energy, from absorbing increasing levels of LWin, adjusts the curvature of the TSL such that there is a lower gradient at the interface between the TSL and the mixed layer. The release of heat stored within the mixed layer is therefore hindered while the additional energy within the TSL is cycled back into the atmosphere. This results in heat beneath the TSL, which is a product of the absorption of solar radiation during the day, to be retained and cause an increase in upper ocean heat content.

Cold-induced vasoconstriction at forearm and hand skin sites: the effect of age.

Science.gov (United States)

Kingma, B R M; Frijns, A J H; Saris, W H M; van Steenhoven, A A; van Marken Lichtenbelt, W D

2010-07-01

During mild cold exposure, elderly are at risk of hypothermia. In humans, glabrous skin at the hands is well adapted as a heat exchanger. Evidence exists that elderly show equal vasoconstriction due to local cooling at the ventral forearm, yet no age effects on vasoconstriction at hand skin have been studied. Here, we tested the hypotheses that at hand sites (a) elderly show equal vasoconstriction due to local cooling and (b) elderly show reduced response to noradrenergic stimuli. Skin perfusion and mean arterial pressure were measured in 16 young adults (Y: 18-28 years) and 16 elderly (E: 68-78 years). To study the effect of local vasoconstriction mechanisms local sympathetic nerve terminals were blocked by bretylium (BR). Baseline local skin temperature was clamped at 33 degrees C. Next, local temperature was reduced to 24 degrees C. After 15 min of local cooling, noradrenaline (NA) was administered to study the effect of neural vasoconstriction mechanisms. No significant age effect was observed in vasoconstriction due to local cooling at BR sites. After NA, vasoconstriction at the forearm showed a significant age effect; however, no significant age effect was found at the hand sites. [Change in CVC (% from baseline): Forearm Y: -76 +/- 3 vs. E: -60 +/- 5 (P forearm, elderly did not show a blunted response to local cooling and noradrenaline at hand skin sites. This indicates that at hand skin the noradrenergic mechanism of vasoconstriction is maintained with age.

Biomarkers of neuropathic pain in skin nerve degeneration neuropathy: contact heat-evoked potentials as a physiological signature.

Science.gov (United States)

Wu, Shao-Wei; Wang, Yi-Chia; Hsieh, Paul-Chen; Tseng, Ming-Tsung; Chiang, Ming-Chang; Chu, Chih-Pang; Feng, Fang-Ping; Lin, Yea-Huey; Hsieh, Sung-Tsang; Chao, Chi-Chao

2017-03-01

Contact heat-evoked potentials (CHEPs) have become an established method of assessing small-fiber sensory nerves; however, their potential as a physiological signature of neuropathic pain symptoms has not been fully explored. To investigate the diagnostic efficacy in examining small-fiber sensory nerve degeneration, the relationship with skin innervations, and clinical correlates with sensory symptoms, we recruited 188 patients (115 men) with length-dependent sensory symptoms and reduced intraepidermal nerve fiber (IENF) density at the distal leg to perform CHEP, quantitative sensory testing, and nerve conduction study. Fifty-seven age- and sex-matched controls were enrolled for comparison of CHEP and skin innervation. Among patients with neuropathy, 144 patients had neuropathic pain and 64 cases had evoked pain. Compared with quantitative sensory testing and nerve conduction study parameters, CHEP amplitudes showed the highest sensitivity for diagnosing small-fiber sensory nerve degeneration and exhibited the strongest correlation with IENF density in multiple linear regression. Contact heat-evoked potential amplitudes were strongly correlated with the degree of skin innervation in both patients with neuropathy and controls, and the slope of the regression line between CHEP amplitude and IENF density was higher in patients with neuropathy than in controls. Patients with evoked pain had higher CHEP amplitude than those without evoked pain, independent of IENF density. Receiver operating characteristic analysis showed that CHEP had better performance in diagnosing small-fiber sensory nerve degeneration than thermal thresholds. Furthermore, CHEPs showed superior classification accuracy with respect to evoked pain. In conclusion, CHEP is a sensitive tool to evaluate pathophysiology of small-fiber sensory nerve and serves as a physiological signature of neuropathic pain symptoms.

Numerical study for Darcy-Forchheimer flow due to a curved stretching surface with Cattaneo-Christov heat flux and homogeneous-heterogeneous reactions

Directory of Open Access Journals (Sweden)

Tasawar Hayat

Full Text Available The current investigation presents Darcy-Forchheimer flow of viscous fluid caused by a curved stretching sheet. Flow for porous space is characterized by Darcy-Forchheimer relation. Concept of homogeneous and heterogeneous reactions is also utilized. Heat transfer for Cattaneo–Christov theory characterizing the feature of thermal relaxation is incorporated. Nonlinear differential systems are derived. Shooting algorithm is employed to construct the solutions for the resulting nonlinear system. The characteristics of various sundry parameters are studied and discussed. Skin friction coefficient and heat transfer rate are numerically described. Keywords: 2D flow, Curved stretching surface, Darcy-Forchheimer porous medium, Cattaneo-Christov heat flux, Homogeneous-heterogeneous reactions

New Approach to Simulation of Heat State of Compartments from Lattice Composite Shells for Space Engineering Products

Directory of Open Access Journals (Sweden)

Razin Alexander F.

2017-01-01

Full Text Available A new approach to the simulation of the heat state of the compartment of lattice polymer composite materials (PCM, not providing for the use of known commercial software packages, has been proposed. The simulation has been performed using the PCM interstage of the Proton rocket as an example with due account of aerodynamic heating, solar radiation and acting of jets of auxiliary propulsion units. At the first stage of numerical analysis, a problem of unsteady heat conduction in the system “skin-air gap-heat insulation” has been solved. An effect of changing a pressure inside a compartment on thermal conductivity of heat insulation was taken into account. The effective thermal conductivity in gaps was used. An effect of a temperature of equipment on a value of radiant heat flux was also taken into account. At the second stage, the heat state of the system “skin-rib” was analyzed. A mathematical model in the form of a system of nonlinear equations for heat balance of control elements on which a rib and a skin section were partitioned, including an information about a temperature of heat insulation received at the first stage of the simulation, was used.

Protective effects of oleum curcumae wenchowensis on skin damage due to UVB

International Nuclear Information System (INIS)

Wang Zhicheng; Zhao Hongguang; Du Xiang; Li Yanbo; Guo Wei; Gong Shouliang; Xiao Jian; Yao Chongshun; Li Xiaokun

2006-01-01

Objective: To study the protective effects of oleum curcumae wenchowensis on skin damage exposed to UVB and its mechanism, and to provide the experimental basis for the protection of skin damage exposed to UVB. Methods: The skin of guinea pigs was exposed to UVB (28.38 J/cm 2 · 30 d) to establish the oxidative damage model. The skin erythema and the rough were observed during the experiment; the thickness of epiderm and the number of fibroblast were observed under light microscope after the experiment. The activities of GSH-Px, SOD, CAT and T-AOC and the contain of MDA in the supernate of skin homogenate were detected with biochemical methods. Results: The epiderm in UVB exposure group and blank group thickened, but that in protective group weren't observed; the number of fibroblast in UVB exposure group and blank group decreased, while that in protective group increased, but that in control group didn't. The content of MDA in the supemate of skin homogenate in UVB exposure group and blank group increased, but that in protective group deceased, and the activities of GSH-Px, SOD, CAT and T-AOC in UVB exposure group and blank group decreased, but those in protective group increased, and control group had no change. Conclusions: Oleum curcumae wenchowensis has the protective effects on skin damage exposed to UVB, which may be mediated by increasing the contain of antioxidases and eliminating the flee radical. (authors)

Heat: A Highly Efficient Skin Enhancer for Transdermal Drug Delivery.

Science.gov (United States)

Szunerits, Sabine; Boukherroub, Rabah

2018-01-01

Advances in materials science and bionanotechnology have allowed the refinements of current drug delivery systems, expected to facilitate the development of personalized medicine. While dermatological topical pharmaceutical formulations such as foams, creams, lotions, gels, etc., have been proposed for decades, these systems target mainly skin-based diseases. To treat systemic medical conditions as well as localized problems such as joint or muscle concerns, transdermal delivery systems (TDDSs), which use the skin as the main route of drug delivery, are very appealing. Over the years, these systems have shown to offer important advantages over oral as well as intravenous drug delivery routes. Besides being non-invasive and painless, TDDSs are able to deliver drugs with a short-half-life time more easily and are well adapted to eliminate frequent administrations to maintain constant drug delivery. The possibility of self-administration of a predetermined drug dose at defined time intervals makes it also the most convenient personalized point-of-care approach. The transdermal market still remains limited to a narrow range of drugs. While small and lipophilic drugs have been successfully delivered using TDDSs, this approach fails to deliver therapeutic macromolecules due to size-limited transport across the stratum corneum , the outermost layer of the epidermis. The low permeability of the stratum corneum to water-soluble drugs as well as macromolecules poses important challenges to transdermal administration. To widen the scope of drugs for transdermal delivery, new procedures to enhance skin permeation to hydrophilic drugs and macromolecules are under development. Next to iontophoresis and microneedle-based concepts, thermal-based approaches have shown great promise to enhance transdermal drug delivery of different therapeutics. In this inaugural article for the section "Frontiers in Bioengineering and Biotechnology," the advances in this field and the handful of

Buoyancy driven flow in a hot water tank due to standby heat loss

DEFF Research Database (Denmark)

Fan, Jianhua; Furbo, Simon

2012-01-01

Results of experimental and numerical investigations of thermal behavior in a vertical cylindrical hot water tank due to standby heat loss of the tank are presented. The effect of standby heat loss on temperature distribution in the tank is investigated experimentally on a slim 150l tank...... show that the CFD model predicts satisfactorily water temperatures at different levels of the tank during cooling by standby heat loss. It is elucidated how the downward buoyancy driven flow along the tank wall is established by the heat loss from the tank sides and how the natural convection flow...... with a height to diameter ratio of 5. A tank with uniform temperatures and with thermal stratification is studied. A detailed computational fluid dynamics (CFD) model of the tank is developed to calculate the natural convection flow in the tank. The distribution of the heat loss coefficient for the different...

Free water content and monitoring of healing processes of skin burns studied by microwave dielectric spectroscopy in vivo

International Nuclear Information System (INIS)

Hayashi, Yoshihito; Miura, Nobuhiro; Shinyashiki, Naoki; Yagihara, Shin

2005-01-01

We have investigated the dielectric properties of human skin in vivo at frequencies up to 10 GHz using a time-domain reflectometry method with open-ended coaxial probes. Since γ-dispersion results from the reorientation of free water molecules, the free water content of skin is quantitatively determined by dielectric measurements. The free water content of finger skin increased by about 10% after soaking in 37 0 C water for 30 min, and it systematically decreased again through the drying process, as expected. Thus this analytical method has been applied to the study of skin burns. The free water content of burned human cheek skin due to hydrofluoric acid was significantly lower than that of normal skin, and the burned skin recovered through the healing process. In the case of a human hand skin burn due to heat, although the free water content was almost the same as that of normal skin at the beginning, it decreased during the healing process for the first 10 days, then began to increase. Although the number of test subjects was one for each experiment, it was shown that free water content is a good indicator for evaluating skin health and can be well monitored by dielectric spectroscopy

Heat-Related Illnesses

Medline Plus

Full Text Available ... exhaustion symptoms include cool, moist, pale or flushed skin; headache; dizziness; weakness; feeling exhausted; heavy sweating; nausea; ... stage of heat illness) include flushed, hot, dry skin; fainting; a rapid, weak pulse; rapid, shallow breathing; ...

Ultrasound skin tightening.

Science.gov (United States)

Minkis, Kira; Alam, Murad

2014-01-01

Ultrasound skin tightening is a noninvasive, nonablative method that allows for energy deposition into the deep dermal and subcutaneous tissue while avoiding epidermal heating. Ultrasound coagulation is confined to arrays of 1-mm(3) zones that include the superficial musculoaponeurotic system and connective tissue. This technology gained approval from the Food and Drug Administration as the first energy-based skin "lifting" device, specifically for lifting lax tissue on the neck, submentum, and eyebrows. Ultrasound has the unique advantage of direct visualization of treated structures during treatment. Ultrasound is a safe and efficacious treatment for mild skin tightening and lifting. Copyright © 2014 Elsevier Inc. All rights reserved.

Impaired Skin Barrier Due to Sebaceous Gland Atrophy in the Latent Stage of Radiation-Induced Skin Injury: Application of Non-Invasive Diagnostic Methods

Directory of Open Access Journals (Sweden)

Hyosun Jang

2018-01-01

Full Text Available Radiation-induced skin injury can take the form of serious cutaneous damage and have specific characteristics. Asymptomatic periods are classified as the latent stage. The skin barrier plays a critical role in the modulation of skin permeability and hydration and protects the body against a harsh external environment. However, an analysis on skin barrier dysfunction against radiation exposure in the latent stage has not been conducted. Thus, we investigated whether the skin barrier is impaired by irradiation in the latent stage and aimed to identify the molecules involved in skin barrier dysfunction. We analyzed skin barrier function and its components in SKH1 mice that received 20 and 40 Gy local irradiation. Increased transepidermal water loss and skin pH were observed in the latent stage of the irradiated skin. Skin barrier components, such as structural proteins and lipid synthesis enzymes in keratinocyte, increased in the irradiated group. Interestingly, we noted sebaceous gland atrophy and increased serine protease and inflammatory cytokines in the irradiated skin during the latent period. This finding indicates that the main factor of skin barrier dysfunction in the latent stage of radiation-induced skin injury is sebaceous gland deficiency, which could be an intervention target for skin barrier impairment.

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

Heat dissipation due to ferromagnetic resonance in a ferromagnetic metal monitored by electrical resistance measurement

International Nuclear Information System (INIS)

Yamanoi, Kazuto; Yokotani, Yuki; Kimura, Takashi

2015-01-01

The heat dissipation due to the resonant precessional motion of the magnetization in a ferromagnetic metal has been investigated. We demonstrated that the temperature during the ferromagnetic resonance can be simply detected by the electrical resistance measurement of the Cu strip line in contact with the ferromagnetic metal. The temperature change of the Cu strip due to the ferromagnetic resonance was found to exceed 10 K, which significantly affects the spin-current transport. The influence of the thermal conductivity of the substrate on the heating was also investigated

Heat deposition on the first wall due to ICRF-induced loss of fast ions in JT-60U

International Nuclear Information System (INIS)

Kusama, Y.; Tobita, K.; Kimura, H.; Hamamatsu, K.; Fujii, T.; Nemoto, M.; Saigusa, M.; Moriyama, S.; Tani, K.; Koide, Y.; Sakasai, A.; Nishitani, T.; Ushigusa, K.

1995-01-01

In JT-60U, the heat deposition on the first wall due to the ICRF-induced loss of fast ions was investigated by changing the position of the resonance layer in the ripple-trapping region. A heat spot appears on the first wall of the same major radius as the resonance layer of the ICRF waves. The broadening of the heat spot in the major radius direction is consistent with that of the resonance layer due to the Doppler broadening. The heat spot is considered to be formed by the ICRF-induced ripple-trapped loss of fast ions. Although the total ICRF-induced loss power to the heat spot is as low as 2% of the total ICRF power, the additional heat flux will become a new issue because of the localized heat deposition on the first wall. ((orig.))

Impairment of Heat Transfer in the Passive Cooling System due to Mixed Convection

Energy Technology Data Exchange (ETDEWEB)

Chae Myeong Seon; Chung, Bum Jin [Kyunghee University, Yongin (Korea, Republic of); Kim, Jong Hwan [KAERI, Daejeon (Korea, Republic of)

2016-05-15

In the passive cooling devices, the buoyant flows are induced. However the local Nusselt number of natural convective flow can be partly impaired due to the development of the mixed convective flows. This paper discusses impairment of heat transfer in the passive cooling system in relation to the development of mixed convection. The present work describes the preliminary plan to explore the phenomena experimentally. This paper is to discuss and make the plan to experiment the impairment of heat transfer in the passive cooling system due to mixed convection. In the sufficiently high passive cooling devices, the natural convection flow behavior can be mixed convection. The local Nusselt number distribution exhibits the non-monotonic behavior as axial position, since the buoyancy-aided with mixed convection was appeared. This is the part of the experimental work.

Mixed convection and heat generation/absorption aspects in MHD flow of tangent-hyperbolic nanoliquid with Newtonian heat/mass transfer

Science.gov (United States)

Qayyum, Sajid; Hayat, Tasawar; Shehzad, Sabir Ali; Alsaedi, Ahmed

2018-03-01

This article concentrates on the magnetohydrodynamic (MHD) stagnation point flow of tangent hyperbolic nanofluid in the presence of buoyancy forces. Flow analysis caused due to stretching surface. Characteristics of heat transfer are examined under the influence of thermal radiation and heat generation/absorption. Newtonian conditions for heat and mass transfer are employed. Nanofluid model includes Brownian motion and thermophoresis. The governing nonlinear partial differential systems of the problem are transformed into a systems of nonlinear ordinary differential equations through appropriate variables. Impact of embedded parameters on the velocity, temperature and nanoparticle concentration fields are presented graphically. Numerical computations are made to obtain the values of skin friction coefficient, local Nusselt and Sherwood numbers. It is concluded that velocity field enhances in the frame of mixed convection parameter while reverse situation is observed due to power law index. Effect of Brownian motion parameter on the temperature and heat transfer rate is quite reverse. Moreover impact of solutal conjugate parameter on the concentration and local Sherwood number is quite similar.

Potential increases in natural radon emissions due to heating of the Yucca Mountain rock mass

International Nuclear Information System (INIS)

Pescatore, C.; Sullivan, T.M.

1992-01-01

Heating of the rock mass by the spent fuel in the proposed repository at Yucca Mountain will cause extra amounts of natural radon to diffuse into the fracture system and to migrate faster to the accessible environment. Indeed, free-convection currents due to heating will act to shorten the radon travel times and will cause larger releases than would be possible under undistributed conditions. To estimate the amount of additional radon released due to heating of the Yucca Mountain rock mass, we obtain an expression for the release enhancement factor, E. This factor is defined as the ratio between the total flux of radon at the surface of the mountain before and after closure of the repository assuming the only cause of disturbance to be the heating of the rock mass. With appropriate approximations and using a heat load representative of that expected at Yucca Mountain, the present calculations indicate that the average enhancement factor over the first 10,000 years will be 4.5 as a minimum. These calculations are based on the assumption that barometric pumping does not significantly influence radon release. The latter assumption will need to be substantiated

Modeling skin blood flow: a neuro-physiological approach

NARCIS (Netherlands)

Kingma, B.R.M.; Saris, W.H.M.; Frijns, A.J.H.; Steenhoven, van A.A.; Marken Lichtenbelt, van W.D.

2010-01-01

In humans skin blood flow (SBF) plays a major role in body heat loss. Therefore the accuracy of models ofhuman thermoregulation depends for a great deal on their ability to predict skin blood flow. Most SBFmodelsuse body temperatures directly for calculation of skin perfusion. However, humans do not

Heat defense control in an experimental heat disorder

Science.gov (United States)

Romanovsky, A. A.; Blatteis, C. M.

Both whole-body heat exposure and intraperitoneal heating (IPH) result in a body temperature (Tb) fall that occurs once heating is abated (''hyperthermia- induced hypothermia''). This phenomenon involves a decrease in the threshold Tb (Tb-thresh) for activation of metabolic heat production (cold defense). Whether the Tb-thresh for ear skin vasodilation (heat defense) also changes during hyperthermia-induced hypothermia remains unknown. In experiment 1, we applied IPH to guinea pigs by perfusing water through a preimplanted intraperitoneal thermode and delivered the total heat load of either approximately 1.5 kJ (''short'' IPH; perfusion duration: 14 min) or approximately 3.0 kJ (''long'' IPH; 40 min). Short IPH caused skin vasodilation and a 1.1°C rise in Tb; no hypothermia occurred when IPH ceased. Long IPH caused vasodilation and hyperthermia of a comparable magnitude (1.4°C) that were followed by a Tb fall to 1.9°C below the preheating value. In experiment 2, the Tb-thresh for skin vasodilation was measured twice: at the beginning of long IPH and at the nadir of the post-IPH hypothermia. The two Tb-thresh values were 39.0 (SEM 0.1)°C and 39.2 (SEM 0.2)°C respectively. In the controls, the Tb-thresh was measured at the beginning and after short IPH; both control values were 39.0 (SEM 0.2)°C. We conclude that the hyperthermia- induced hypothermia, although previously shown to be coupled with a decrease in the Tb-thresh for cold defense, occurs without any substantial change in the Tb-thresh for heat defense. We speculate that postheating thermoregulatory disorders are associated with threshold dissociation, thus representing the poikilothermic (wide dead-band) type of Tb control.

Preventing skin injury during MR imaging for gamma knife surgery. Necessity and verification of insulated posts for fixation of leksell G-frame

International Nuclear Information System (INIS)

Kenai, Hiroyuki; Yamashita, Masanori; Yamada, Akira; Asano, Tomoshige; Wakabayashi, Yukihiro; Nagatomi, Hirofumi

2011-01-01

conventional posts. It is important to consider that performing MR imaging may induce heating of human tissues and that the risk of heat generation is increased especially when a patient is wearing a metal frame around his or her head for GKS or other purposes, due to loop formation. With the wide spread use of high-magnetic field MR apparatuses, IFP should be used on a routine basis for frame fixation during GKS to completely avoid the risk of heat generation and subsequent skin injury. (author)

Differential Response to Heat Stress in Outer and Inner Onion Bulb Scales.

Science.gov (United States)

Galsurker, Ortal; Doron-Faigenboim, Adi; Teper-Bamnolker, Paula; Daus, Avinoam; Lers, Amnon; Eshel, Dani

2018-05-18

Brown protective skin formation in onion bulbs can be induced by rapid postharvest heat treatment. Onions that were peeled to different depths and were exposed to heat stress showed that only the outer scale formed dry brown skin, whereas the inner scales maintained high water content and did not change color. Our results reveal that browning of the outer scale during heat treatment is due to an enzymatic process that is associated with high levels of oxidation components, such as peroxidase and quercetin glucoside. De-novo transcriptome analysis revealed differential molecular responses of the outer and inner scales to the heat stress. Genes involved in lipid metabolism, oxidation pathways and cell-wall modification were highly expressed in the outer scale during heating. Defense-response-related genes such as those encoding heat-shock proteins, antioxidative stress defense or production of osmoprotectant metabolites were mostly induced in the inner scale in response to the heat exposure. These transcriptomic data led to a conceptual model that suggests sequential processes for browning development and desiccation of the outer scales versus processes associated with defense response and heat tolerance in the inner scale. Thus, the observed physiological differences between the outer and inner scales is supported by the identified molecular differences.

Roman Lyariev, How to Skin Your Kill

OpenAIRE

Gedeeva, Darina; Ubushieva, Bamba; Babaev, Andrei

2016-01-01

Roman explains how to skin a fox. First, one needs to prepare the ground by trampling it. Skinning should be done with a small sharp knife. A freshly killed fox skins easily. Then one needs to treat the skin with an anti-flea spray. At home the skin should be stretched on a triangular wooden panel called in Russian pravilka and left in a dry room for up to five days. People usually go hunting when foxes are on heat and are busy fighting with each other for females. When the wind is strong, fo...

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.

Infrared thermography based studies on mobile phone induced heating

Science.gov (United States)

Lahiri, B. B.; Bagavathiappan, S.; Soumya, C.; Jayakumar, T.; Philip, John

2015-07-01

Here, we report the skin temperature rise due to the absorption of radio frequency (RF) energy from three handheld mobile phones using infrared thermography technique. Experiments are performed under two different conditions, viz. when the mobile phones are placed in soft touch with the skin surface and away from the skin surface. Additionally, the temperature rise of mobile phones during charging, operation and simultaneous charging and talking are monitored under different exposure conditions. It is observed that the temperature of the cheek and ear regions monotonically increased with time during the usage of mobile phones and the magnitude of the temperature rise is higher for the mobile phone with higher specific absorption rate. The increase in skin temperature is higher when the mobile phones are in contact with the skin surface due to the combined effect of absorption of RF electromagnetic power and conductive heat transfer. The increase in the skin temperature in non-contact mode is found to be within the safety limit of 1 °C. The measured temperature rise is in good agreement with theoretical predictions. The empirical equation obtained from the temperature rise on the cheek region of the subjects correlates well with the specific absorption rate of the mobile phones. Our study suggests that the use of mobile phones in non-contact mode can significantly lower the skin temperature rise during its use and hence, is safer compared to the contact mode.

Contribution of natural ventilation in a double skin envelope to heating load reduction in winter

Energy Technology Data Exchange (ETDEWEB)

Kim, Yu-Min; Sohn, Jang-Yeul [Department of Architectural Engineering, Hanyang University, Seoul (Korea); Kim, Soo-Young [Department of Housing and Interior Design, Yonsei University, Seoul (Korea); Shin, Sung-Woo [Department of Architectural Engineering, Hanyang University, Ansan (Korea)

2009-11-15

This study examined the contribution of a double skin envelope (DSE) to the heating energy savings brought about by natural ventilation in office buildings. A DSE was applied to the east- and west-facing walls on an actual three-floor building. Field measurements and computer simulations were performed in winter. The results implied that the DSE on the west-facing wall contributed to energy savings when natural ventilation was supplied from the cavity to the indoor space. The DSE facing east was not recommended for energy savings by natural ventilation because of its smaller exposure to solar irradiance. Multiple linear regression models were developed based on field measurements to predict the temperature variation in the cavities, and effective control logics will be discussed in a future study. Of all variables, the outdoor air temperature was the most significant factor influencing the air temperature in the cavity. Computer simulation indicated that the air in the cavity was heated to the required temperature without consuming additional energy when the ratio of the diffused irradiance to global irradiance was smaller than 0.69. The cavity in the DSE worked as a thermal buffer zone and contributed to reducing heating energy consumption by 14.71% in January. (author)

Heat: A Highly Efficient Skin Enhancer for Transdermal Drug Delivery

Directory of Open Access Journals (Sweden)

Sabine Szunerits

2018-02-01

Full Text Available Advances in materials science and bionanotechnology have allowed the refinements of current drug delivery systems, expected to facilitate the development of personalized medicine. While dermatological topical pharmaceutical formulations such as foams, creams, lotions, gels, etc., have been proposed for decades, these systems target mainly skin-based diseases. To treat systemic medical conditions as well as localized problems such as joint or muscle concerns, transdermal delivery systems (TDDSs, which use the skin as the main route of drug delivery, are very appealing. Over the years, these systems have shown to offer important advantages over oral as well as intravenous drug delivery routes. Besides being non-invasive and painless, TDDSs are able to deliver drugs with a short-half-life time more easily and are well adapted to eliminate frequent administrations to maintain constant drug delivery. The possibility of self-administration of a predetermined drug dose at defined time intervals makes it also the most convenient personalized point-of-care approach. The transdermal market still remains limited to a narrow range of drugs. While small and lipophilic drugs have been successfully delivered using TDDSs, this approach fails to deliver therapeutic macromolecules due to size-limited transport across the stratum corneum, the outermost layer of the epidermis. The low permeability of the stratum corneum to water-soluble drugs as well as macromolecules poses important challenges to transdermal administration. To widen the scope of drugs for transdermal delivery, new procedures to enhance skin permeation to hydrophilic drugs and macromolecules are under development. Next to iontophoresis and microneedle-based concepts, thermal-based approaches have shown great promise to enhance transdermal drug delivery of different therapeutics. In this inaugural article for the section “Frontiers in Bioengineering and Biotechnology,” the advances in this field

Heat: A Highly Efficient Skin Enhancer for Transdermal Drug Delivery

Science.gov (United States)

Szunerits, Sabine; Boukherroub, Rabah

2018-01-01

Advances in materials science and bionanotechnology have allowed the refinements of current drug delivery systems, expected to facilitate the development of personalized medicine. While dermatological topical pharmaceutical formulations such as foams, creams, lotions, gels, etc., have been proposed for decades, these systems target mainly skin-based diseases. To treat systemic medical conditions as well as localized problems such as joint or muscle concerns, transdermal delivery systems (TDDSs), which use the skin as the main route of drug delivery, are very appealing. Over the years, these systems have shown to offer important advantages over oral as well as intravenous drug delivery routes. Besides being non-invasive and painless, TDDSs are able to deliver drugs with a short-half-life time more easily and are well adapted to eliminate frequent administrations to maintain constant drug delivery. The possibility of self-administration of a predetermined drug dose at defined time intervals makes it also the most convenient personalized point-of-care approach. The transdermal market still remains limited to a narrow range of drugs. While small and lipophilic drugs have been successfully delivered using TDDSs, this approach fails to deliver therapeutic macromolecules due to size-limited transport across the stratum corneum, the outermost layer of the epidermis. The low permeability of the stratum corneum to water-soluble drugs as well as macromolecules poses important challenges to transdermal administration. To widen the scope of drugs for transdermal delivery, new procedures to enhance skin permeation to hydrophilic drugs and macromolecules are under development. Next to iontophoresis and microneedle-based concepts, thermal-based approaches have shown great promise to enhance transdermal drug delivery of different therapeutics. In this inaugural article for the section “Frontiers in Bioengineering and Biotechnology,” the advances in this field and the handful of

[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).

Numerical simulation of the transport phenomena due to sudden heating in porous media

Energy Technology Data Exchange (ETDEWEB)

Lei, S.Y.; Zheng, G.Y.; Wang, B.X.; Yang, R.G.; Xia, C.M.

1997-07-01

Such process as wet porous media suddenly heated by hot fluids frequently occurs in nature and in industrial applications. The three-variable simulation model was developed to predict violent transport phenomena due to sudden heating in porous media. Two sets of independent variables were applied to different regions in porous media in the simulation. For the wet zone, temperature, wet saturation and air pressure were used as the independent variables. For the dry zone, the independent variables were temperature, vapor pressure and air pressure. The model simulated two complicated transport processes in wet unsaturated porous media which is suddenly heated by melting metal or boiling water. The effect of the gas pressure is also investigated on the overall transport phenomena.

Beyond UV radiation: a skin under challenge.

Science.gov (United States)

Dupont, E; Gomez, J; Bilodeau, D

2013-06-01

Since ancient times, human beings have been trying to protect their skin against the adverse effects of the sun. From the first mineral sunscreens used by Egyptians, to the current more sophisticated ultraviolet (UVA/UVB) organic sunscreens, progress has been made in terms of sun protection and deeper knowledge of skin physiology has been acquired in the process. The solar spectrum is composed of radiations of various wavelengths having specific, as well as overlapping effects on skin. UVB is mainly responsible for sunburn and DNA dimer formation that can lead to mutation. UVA generates oxidative reactions affecting DNA, proteins and lipids, and is also immunosuppressive. Recently, visible light and infrared radiation (IR) have been associated with oxidative damage and IR has been additionally linked to adverse heat effects on skin. Numerous other extrinsic factors, related to environment and lifestyle, also affect the appearance of skin, precipitating ageing. New molecular mechanisms linking sun and environmental factors to skin ageing have been identified: IR affects mitochondrial integrity and specific heat receptors also mediate some of its effects, tryptophan is a chromophore for UVB, and the aryl hydrocarbon receptor (AhR) is activated by light and xenobiotics to alter skin physiology. Integrating all these new elements is changing the way we think about skin extrinsic ageing. Is UVA/UVB sunscreen protection still enough for our skin? © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Solar Heat Gain Reduction of Ventilated Double Skin Windows without a Shading Device

Directory of Open Access Journals (Sweden)

Bokyoung Koo

2017-12-01

Full Text Available With global efforts to strengthen various energy-saving policies for buildings to reduce greenhouse gas emissions, in South Korea, new laws and regulations have been in force since May 2015 to install shading devices in public buildings and to include the solar heat gain coefficient (SHGC reduction performance of shading devices in the evaluation of building performance. By making a ventilated air layer outer glass and inner glass to lower the temperatures of the air layer and glass surface, it is possible to reduce the amount of heat flowing into the building while maintaining the same level of light transmission as plain window systems. This study proposes a double-skin façade window with a 20 mm ventilated air cavity, and assumes that insolation inflow indoors would be reduced through ventilation in the air cavity. The artificial solar lab test results show that the SHGC can be lowered through ventilation by 28% to 52.9%. Additionally, in an outdoor test cell experiment, the results show that the mean temperature was 0.6 K and the peak temperature was 0.9 K lower with ventilation in the air cavity than that without ventilation in the air cavity.

Intermittent cryogen spray cooling for optimal heat extraction during dermatologic laser treatment

Science.gov (United States)

Majaron, Boris; Svaasand, Lars O.; Aguilar, Guillermo; Nelson, J. Stuart

2002-09-01

Fast heat extraction is critically important to obtain the maximal benefit of cryogen spray cooling (CSC) during laser therapy of shallow skin lesions, such as port wine stain birthmarks. However, a film of liquid cryogen can build up on the skin surface, impairing heat transfer due to the relatively low thermal conductivity and higher temperature of the film as compared to the impinging spray droplets. In an attempt to optimize the cryogen mass flux, while minimally affecting other spray characteristics, we apply a series of 10 ms spurts with variable duty cycles. Heat extraction dynamics during such intermittent cryogen sprays were measured using a custom-made metal-disc detector. The highest cooling rates were observed at moderate duty cycle levels. This confirms the presence, and offers a practical way to eliminate the adverse effect of liquid cryogen build-up on the sprayed surface. On the other hand, lower duty cycles allow a substantial reduction in the average rate of heat extraction, enabling less aggressive and more efficient CSC for treatment of deeper targets, such as hair follicles.

Extra Heat Loss Through Light Weight Roofs Due to Latent Heat

DEFF Research Database (Denmark)

Rode, Carsten

1996-01-01

that changes phase at the terminals of its passage.Note however, that convection of air most often will have an important effect on the overall heat flow - but that is a different topic.Macroscopic latent heat transferConsider the following scenario: Initially, moisture is present in its condensed or frozen......This report is one in a series of papers in Task 5 of IEA Annex 24 on how moisture and air movements affect the energy performance of building constructions. The effect of latent heat flow will be demonstrated by means of an example: a light weight flat roof.Latent heat flow is one of three...... processes by which moisture affects energy performance:Higher thermal conductivityMoist materials have higher thermal con-ductivity than when they are dry. This is because thermally conducting moisture replaces the better insulating air in the pores of the materials. Moisture also enhan-ces the thermal...

Analytical prediction of the heat transfer from a blood vessel near the skin surface when cooled by a symmetrical cooling strip

Science.gov (United States)

Chato, J. C.; Shitzer, A.

1971-01-01

An analytical method was developed to estimate the amount of heat extracted from an artery running close to the skin surface which is cooled in a symmetrical fashion by a cooling strip. The results indicate that the optimum width of a cooling strip is approximately three times the depth to the centerline of the artery. The heat extracted from an artery with such a strip is about 0.9 w/m-C which is too small to affect significantly the temperature of the blood flow through a main blood vessel, such as the carotid artery. The method is applicable to veins as well.

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

Time behaviours of visible lines in turbulently heated TRIAM-1 plasma

Energy Technology Data Exchange (ETDEWEB)

Hiraki, N; Nakamura, K; Nakamura, Y; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1981-08-01

Spectroscopic studies were carried out on turbulently heated TRIAM-1 tokamak plasma. The temporal evolutions of the line radiance of visible lines were measured and two types of time behaviours of the line radiance were identified. The observed remarkable reduction of the line radiance of visible lines which have low ionization potential and are localized in the skin-layer due to the application of a pulsed electric-field for turbulent heating is attributed to the strong plasma heating in the peripherical region. Spatial profiles of neutrals and ions which are related to these lines are calculated, and the temporal variations of these profiles caused by the application of the heating pulse are discussed.

Occupational skin cancer due to UV-irradiation--Analyses of notified cases as "virtually-certain" occupational disease in Germany between 2005 and 2011.

Science.gov (United States)

Schmitt, Jochen; Diepgen, Thomas L

2014-06-01

UV-induced skin cancer is not yet included in the German ordinance on occupational diseases and can only be notified and recognized acknowledged as "virtually-certain" occupational disease. The objective of the study was to analyze notified and acknowledged cases of occupational skin cancer due to UV-irradiation in Germany between 2005 and 2011. All notified cases of occupational skin cancer due to UV-irradiation have been analyzed which have been registered by the German Statutory accident insurance as of May 2012 were analyzed. The data analyze was descriptive stratified annually for presenting time trends.Data analysis was descriptive, stratified by year to defect time trends. Notified cases have increased annually with a total of 548 registered cases of occupational skin cancer induced by UV-irradiation between 2005 and 2011, and 74 recognized acknowledged cases. In 56 cases the procedure was not yet finished. Squamous cell carcinoma (SCC) and in-situ squamous cell carcinoma (actinic keratosis, Bowen's disease) were most frequent and have been the most frequentlyobserved in 333 notified cases. and between 15.6 % and 24.9 % have been recognizedof cases with SCC and actinic keratosis were recognized, respectively. 184 patients with basal cell carcinoma were notified but only 6.5 % recognized acknowledged and only 3 cases with exclusive basal cell carcinoma. Out of 50 notified patients with Mmelanoma only one was recognizedacknowledged. The results are in good agreement with the proposal of the German Minister of labor to establish UV-induced skin cancer as a new occupational disease. © 2014 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

On the Road to Development of an in Vitro Permeation Test (IVPT) Model to Compare Heat Effects on Transdermal Delivery Systems: Exploratory Studies with Nicotine and Fentanyl.

Science.gov (United States)

Shin, Soo Hyeon; Ghosh, Priyanka; Newman, Bryan; Hammell, Dana C; Raney, Sam G; Hassan, Hazem E; Stinchcomb, Audra L

2017-09-01

At elevated temperatures, the rate of drug release and skin permeation from transdermal delivery systems (TDS) may be higher than at a normal skin temperature. The aim of this study was to compare the effect of heat on the transdermal delivery of two model drugs, nicotine and fentanyl, from matrix-type TDSs with different formulations, using in vitro permeation tests (IVPT). IVPT experiments using pig skin were performed on two nicotine and three fentanyl TDSs. Both continuous and transient heat exposures were investigated by applying heat either for the maximum recommended TDS wear duration or for short duration. Continuous heat exposure for the two nicotine TDSs resulted in different effects, showing a prolonged heat effect for one product but not the other. The J max enhancement ratio due to the continuous heat effect was comparable between the two nicotine TDS, but significantly different (p drug from the skin depot after TDS removal differently for two drugs, with fentanyl exhibiting a longer heat effect. This exploratory work suggests that an IVPT study may be able to discriminate differences in transdermal drug delivery when different TDS are exposed to elevated temperatures. However, the clinical significance of IVPT heat effects studies should be further explored by conducting in vivo clinical studies with similar study designs.

Influence of porous PTFE/LDPE/PP composite electret in skin ultrastructure

International Nuclear Information System (INIS)

Jiang, J; Liang, Y Y; Tang, Y; Ye, X T; Yang, Y J; Song, M H; Cui, L L; Hou, X M

2008-01-01

Corona charging and heat melting method were used to prepare porous PTFE electret and porous PTFE/LDPE/PP composite electret, respectively. After 0.5, 1, 1.5, 3 and 4 hour's action of fluorescein sodium (FINa) and -300V porous PTFE/LDPE/PP composite electret on the excised abdominal skin of rat, the skin structure was studied by means of scanning electron microscopy, transmission electron microscopy and confocal laser scanning microscopy, respectively, to probe the mechanism of electret on transdermal drug delivery. The results indicated that negative electret could increase the transdermal delivery of FINa due to its effect on changing the organized structure of stratum corneum, enlarging the hair follicles, which may be the mechanism of electret in enhancing transdermal drug delivery.

Unsteady Flow of Reactive Viscous, Heat Generating/Absorbing Fluid with Soret and Variable Thermal Conductivity

Directory of Open Access Journals (Sweden)

I. J. Uwanta

2014-01-01

Full Text Available This study investigates the unsteady natural convection and mass transfer flow of viscous reactive, heat generating/absorbing fluid in a vertical channel formed by two infinite parallel porous plates having temperature dependent thermal conductivity. The motion of the fluid is induced due to natural convection caused by the reactive property as well as the heat generating/absorbing nature of the fluid. The solutions for unsteady state temperature, concentration, and velocity fields are obtained using semi-implicit finite difference schemes. Perturbation techniques are used to get steady state expressions of velocity, concentration, temperature, skin friction, Nusselt number, and Sherwood number. The effects of various flow parameters such as suction/injection (γ, heat source/sinks (S, Soret number (Sr, variable thermal conductivity δ, Frank-Kamenetskii parameter λ, Prandtl number (Pr, and nondimensional time t on the dynamics are analyzed. The skin friction, heat transfer coefficients, and Sherwood number are graphically presented for a range of values of the said parameters.

Nonsurgical tightening of skin laxity: a new radiofrequency approach.

Science.gov (United States)

Rusciani, Antonio; Curinga, Giuseppe; Menichini, Giulio; Alfano, Carmine; Rusciani, Luigi

2007-04-01

Improvement in skin laxity can be difficult to achieve without invasive surgical procedures. Monopolar radiofrequency (RF) treatment is used by physicians to heat skin and promote tissue tightening and contouring. RF technology produces an electric current that generates heat through resistance in the dermis and subcutaneous tissue. The thermal effect depends on the conductivity features of the treated tissue. When heated, collagen fibrils will denature and contract, which is believed to lead to the observed tissue tightening. Ninety-three consecutive patients with mild to moderate laxity were included in the study. The Surgitron Dual Frequency RF (Radiowave technology, Ellman International) was used to treat skin laxity. The application of RF energy took place in an ambulatory setting with no need for skin sterilization or anesthesia. Patients immediately noticed a microlifting retraction in the treated tissues according to the vectors mapped in the area. There were no significant complications and the majority of patients were satisfied with the procedure and able to return to their daily routine after leaving the office, thereby substantiating the popularity of noninvasive rejuvenating procedures.

Calculation of skin dose due to beta contamination using the new quantity of the ICRP 116: the local skin dose

International Nuclear Information System (INIS)

Bourgois, L.; Menard, S.; Comte, N.

2017-01-01

Values of the new protection quantity Local Skin Dose 'LSD', introduced by the International Commission on Radiological Protection (ICRP) Publication 116, were calculated for 134 β - or β + emitting radionuclides, using the Monte Carlo code MCNP6. Two types of source geometry are considered: a point source and disc-type surface contamination (the source is placed in contact with the skin). This new protection quantity is compared with the operational quantity H2 (0.07, 0 deg.), leading us to conclude that, in accordance with the rules of the ICRP, the operational quantity over-estimates the protection quantity to a reasonable extent, except in very rare cases for very low average beta energies. Thus, with the new skin model described in ICRP 116, there are no longer any major differences between the operational quantities and protection quantities estimated with the skin model described in ICRP 74. (authors)

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.

Resonance localization and poloidal electric field due to cyclo- tron wave heating in tokamak plasmas

International Nuclear Information System (INIS)

Hsu, J.Y.; Chan, V.S.; Harvey, R.W.; Prater, R.; Wong, S.K.

1984-01-01

The perpendicular heating in cyclotron waves tends to pile up the resonant particles toward the low magnetic field side with their banana tips localized to the resonant surface. A poloidal electric field with an E x B drift comparable to the ion vertical drift in a toroidal magnetic field may result. With the assumption of anomalous electron and neoclassical ion transport, density variations due to wave heating are discussed

Heat generation and temperature-rise in ordinary concrete due to capture of thermal neutrons

International Nuclear Information System (INIS)

Abdo, E.A.; Amin, E.

1997-01-01

The aim of this work is the evaluation of the heat generation and temperature-rise in local ordinary concrete as a biological shield due to capture of total thermal and reactor thermal neutrons. The total thermal neutron fluxes were measured and calculated. The channel number 2 of the ETRR-1 reactor was used in the measurements as a neutron source. Computer code ANISN (VAX version) and neutron multigroup cross-section library EURLiB-4 was used in the calculations. The heat generation and temperature-rise in local ordinary concrete were evaluated and calculated. The results were displayed in curves to show the distribution of thermal neutron fluxes and heat generation as well as temperature-rise with the shield thickness. The results showed that, the heat generation as well as the temperature-rise have their maximum values in the first layers of the shield thickness. 4 figs., 12 refs

Nonlinear radiated MHD flow of nanoliquids due to a rotating disk with irregular heat source and heat flux condition

Science.gov (United States)

Mahanthesh, B.; Gireesha, B. J.; Shehzad, S. A.; Rauf, A.; Kumar, P. B. Sampath

2018-05-01

This research is made to visualize the nonlinear radiated flow of hydromagnetic nano-fluid induced due to rotation of the disk. The considered nano-fluid is a mixture of water and Ti6Al4V or AA7072 nano-particles. The various shapes of nanoparticles like lamina, column, sphere, tetrahedron and hexahedron are chosen in the analysis. The irregular heat source and nonlinear radiative terms are accounted in the law of energy. We used the heat flux condition instead of constant surface temperature condition. Heat flux condition is more relativistic and according to physical nature of the problem. The problem is made dimensionless with the help of suitable similarity constraints. The Runge-Kutta-Fehlberg scheme is adopted to find the numerical solutions of governing nonlinear ordinary differential systems. The solutions are plotted by considering the various values of emerging physical constraints. The effects of various shapes of nanoparticles are drawn and discussed.

Temperature distribution of a simplified rotor due to a uniform heat source

Science.gov (United States)

Welzenbach, Sarah; Fischer, Tim; Meier, Felix; Werner, Ewald; kyzy, Sonun Ulan; Munz, Oliver

2018-03-01

In gas turbines, high combustion efficiency as well as operational safety are required. Thus, labyrinth seal systems with honeycomb liners are commonly used. In the case of rubbing events in the seal system, the components can be damaged due to cyclic thermal and mechanical loads. Temperature differences occurring at labyrinth seal fins during rubbing events can be determined by considering a single heat source acting periodically on the surface of a rotating cylinder. Existing literature analysing the temperature distribution on rotating cylindrical bodies due to a stationary heat source is reviewed. The temperature distribution on the circumference of a simplified labyrinth seal fin is calculated using an available and easy to implement analytical approach. A finite element model of the simplified labyrinth seal fin is created and the numerical results are compared to the analytical results. The temperature distributions calculated by the analytical and the numerical approaches coincide for low sliding velocities, while there are discrepancies of the calculated maximum temperatures for higher sliding velocities. The use of the analytical approach allows the conservative estimation of the maximum temperatures arising in labyrinth seal fins during rubbing events. At the same time, high calculation costs can be avoided.

Occupational skin cancers

Energy Technology Data Exchange (ETDEWEB)

Gawkrodger, D.J. [Royal Hallamshire Hospital, Sheffield (United Kingdom). Dept. of Dermatology

2004-10-01

Skin cancer due to occupation is more common than is generally recognized, although it is difficult to obtain an accurate estimate of its prevalence. Over the past two centuries, occupational skin cancers have particularly been due to industrial exposure of men (it seems more so than women) to chemical carcinogens such as polycyclic hydrocarbons (e.g. from coal tar products) or to arsenic. Industrial processes have improved in most Western countries to limit this type of exposure, but those with outdoor occupations are still exposed to solar ultraviolet irradiation without this being widely recognized as an industrial hazard. Ionizing radiation such as X-rays can also cause skin cancer. Occupational skin cancers often resemble skin tumours found in non-occupational subjects, e.g. basal cell carcinoma, squamous cell carcinoma and malignant melanoma, but some pre-malignant lesions can be more specific and point to an occupational origin, e.g. tar keratoses or arsenical keratoses. An uncommon but well-recognized cause of occupational skin cancer is that which results from scar formation following an industrial burn. In the future it will be necessary to focus on preventative measures, e.g. for outdoor workers, the need to cover up in the sun and use sun protective creams and a campaign for earlier recognition of skin cancers, which are usually curable if treated in their early stages.

Hot Films on Ceramic Substrates for Measuring Skin Friction

Science.gov (United States)

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

2003-01-01

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

Transient thermal stresses in composite hollow circular cylinder due to partial heat generation

International Nuclear Information System (INIS)

Goshima, Takahito; Miyao, Kaju

1979-01-01

Clad materials are adopted for the machines and structures used in contact with high temperature, corrosive atmosphere in view of their strength and economy. Large thermal stress sometimes arises in clad cylinders due to uneaven temperature field and the difference in linear thermal expansion. Vessels are often heated uneavenly, and shearing stress occurs, which is not observed in uniform heating. In this study, infinitely long, concentric cylinders of two layers were analyzed, when the internal heat changing in stepped state is generated in cylindrical form. The unsteady thermal stress occurred was determined, using thermo-elastic potential and stress functions, and assuming the thermal properties and elastic modulus of materials as constant regardless of the temperature. Laplace transformation was used, and the basic equations for thermo-elastic displacement were employed as the basis of calculation. The analysis of the temperature distribution and stress is explained. Numerical calculation was carried out on the example of an internal cylinder of SUS 304 stainless steel and an external cylinder of mild steel. The maximum shearing stress occurred in the direction of 40 deg from the heat source, and was affected largely by the position of heat generation. The effect became remarkable as time elapsed. (Kako, I.)

Regional relation between skin blood flow and sweating to passive heating and local administration of acetylcholine in young, healthy humans.

Science.gov (United States)

Smith, Caroline J; Kenney, W Larry; Alexander, Lacy M

2013-04-01

Regional variation in sweating over the human body is widely recognized yet variation in vasomotor responses and mechanisms causing this variation remain unclear. This study aimed to explore the relation between regional sweating rates (RSR) and skin blood flow (SkBF) responses to thermal and pharmacological stimuli in young, healthy subjects. In nine subjects (23 ± 3 yr), intradermal microdialysis (MD) probes were inserted into the ventral forearm, abdomen, thigh, and lower back and perfused with lactated Ringer solution. RSR over each MD membrane were measured using ventilated capsules with a laser Doppler probe housed in each capsule for measurement of red cell flux (laser Doppler flux, LDF) as an index of SkBF. Subjects completed a whole body heating protocol to 1°C rise in oral temperature and an acetylcholine dose response (ACh 1 × 10(-7)-0.1 M; mean skin temperature 34°C). Maximal LDF were obtained at the end of both protocols (50 mM sodium nitroprusside).During heating RSR varied among sites (P back versus other sites (P back: r = 0.86 ± 0.04) but not latter stages of heating. No differences in RSR (P = 0.160) or SkBF (LDF, P = 0.841) were observed between sites during ACh perfusion. Taken together, these data suggest that increases in SkBF are necessary to initiate and increase sweating, but further rises in RSR are not fully dependent on SkBF in a dose-response manner. Furthermore, RSR cannot be explained by cholinergic sensitivity or variation in SkBF.

Heat exchanger nozzle stresses due to pipe vibration

International Nuclear Information System (INIS)

Wolgemuth, G.A.

1983-01-01

A large diameter pipe in a heavy water production plant was excited into a low frequency vibration due to void collapse of the pipe contents at a sharp vertical drop in the pipe run. Fears that this vibration would fatigue the inlet nozzle to the heat exchanger prompted the introduction of a flow of cold water into the pipe to prevent the two-phase flow from developing but at the cost of reduced heat exchanger efficiency. An investigation was carried out to determine the stress levels in the nozzle with the quenching flow off and suggest means of reducing them if excessive. A finite element dynamic simulation of the pipe run was performed to determine the likely mode shapes. This information was used to optimize the placement of velocity probes on the pipe. Field measurements of vibration were taken for several operating conditions. This data was analyzed and the results used to refine the support stiffness used in the finite element simulation. The finite element model was then used to predict the nozzle forces and moments. In turn this data was used to determine the local stresses in the nozzle. The ASME Section III code was used to determine the allowable fully reversing stresses for the unit in question. It was found that the endurance limit of 83 MPa was exceeded in the analysis only when using the most conservative estimates for each uncertainty. It was recommended that if the safety factor was not deemed high enough, the nozzle should be built up with a reinforcing pad no thicker than 12 mm

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.

Modeling Skin Injury from Hot Spills on Clothing

Directory of Open Access Journals (Sweden)

Torgrim Log

2017-11-01

Full Text Available The present work analyzes scald burns from hot beverages, such as coffee and tea, spilled on the lap, i.e., an incident that may occur in daily life. The Pennes bioheat equation is solved numerically for small spills wetting the clothing, i.e., the fabric prevents the spilled liquid from draining away. Temperatures are analyzed in the wetted fabric and the skin layers and the resulting skin injury is calculated based on the basal layer temperature. Parameters influencing burn severity, such as clothing thickness, liquid temperature, removal of fabric and thermal effects of post scald water cooling are analyzed. The fabric cools the water some but represents a threat since the entrapped water results in a prolonged heat supply. The liquid temperature turned out to be the most important injury parameter, where liquid temperature of about 80–85 °C seems to be a limit for developing superficial partial-thickness burns in the present minimum case, i.e., where the liquid just wets the fabric. Spilling water in excess of just wetting the fabric, more severe burns will develop at lower liquid temperatures due to the prolonged heat supply. Higher liquid temperatures will nearly instantly develop more severe burns. It is demonstrated that removal of the clothing within the first seconds after the spill may significantly reduce the scalding severity. The general advice is therefore to avoid excessive heating of beverages and, if the beverage is spilled, to quickly remove the wetted clothing. Prolonged tempered water cooling is advised to improve the healing processes.

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

Skin painting studies

International Nuclear Information System (INIS)

Witschi, H.P.; Smith, L.H.; Goad, M.E.; Anthony, W.B.; Gipson, L.C.; Stephens, T.J.; Whitaker, M.S.

1987-01-01

In order to estimate eventual risks to human health as a consequence of incidental and prolonged skin contact, it is necessary to obtain some information on the potential of coal-derived liquids to elicit skin cancer. In addition, it also must be established whether prolonged dermal exposure will produce signs of toxicity not only on the skin but to internal organs. During the past 2 years, they completed a life-long skin painting study with mice designed to answer some of these questions. The following materials were tested: Raw H-coal blend, containing 5700 ppm N; H-coal blend after low hydrotreatment (2650 ppm N); H-coal blend after high hydrotreatment (0.2 ppm N); H-coal home heating oil, a devolatilized version of the high-hydrotreatment H-coal blend; and an H-coal reformed naphtha. Two petroleum-derived references samples were used: Petroleum No. 2 fuel oil and high catalytically cracked naphtha. Benzo(a)pyrene was used as reference substance. Experimental animals were male and female C3H mice

The Pelleve procedure: an effective method for facial wrinkle reduction and skin tightening.

Science.gov (United States)

Stampar, Michael

2011-05-01

Devices using radiofrequency (RF) energy and electrical energy to deliver a controlled thermal injury to heat skin have proliferated within the nonablative skin treatment market since the introduction of Thermage in 2002. By delivering continuous monopolar RF energy, rather than pulsed heating, and repeatedly bringing the skin to therapeutic temperatures until maximal contraction is obtained, the Pelleve Procedure can give obvious cosmetic results confluently over all treated areas painlessly and with no downtime. In this article, the technique, mechanism of continuous RF heating, and apparent treatment requirements to produce these results are presented. Some controversies are also addressed. Copyright © 2011 Elsevier Inc. All rights reserved.

Improved energy efficiency in juice production through waste heat recycling

International Nuclear Information System (INIS)

Anderson, J.-O.; Elfgren, E.; Westerlund, L.

2014-01-01

Highlights: • A heating system at a juice production was investigated and improved. • Different impacts of drying cycle improvements at the energy usage were explored. • The total heat use for drying could thereby be decreased with 52%. • The results point out a significant decrease of heat consumption with low investment costs. - Abstract: Berry juice concentrate is produced by pressing berries and heating up the juice. The by-products are berry skins and seeds in a press cake. Traditionally, these by-products have been composted, but due to their valuable nutrients, it could be profitable to sell them instead. The skins and seeds need to be separated and dried to a moisture content of less than 10 %wt (on dry basis) in order to avoid fermentation. A berry juice plant in the north of Sweden has been studied in order to increase the energy and resource efficiency, with special focus on the drying system. This was done by means of process integration with mass and energy balance, theory from thermodynamics and psychrometry along with measurements of the juice plant. Our study indicates that the drying system could be operated at full capacity without any external heat supply using waste heat supplied from the juice plant. This would be achieved by increasing the efficiency of the dryer by recirculation of the drying air and by heat supply from the flue gases of the industrial boiler. The recirculation would decrease the need of heat in the dryer with about 52%. The total heat use for the plant could thereby be decreased from 1262 kW to 1145 kW. The improvements could be done without compromising the production quality

Projected changes in atmospheric heating due to changes in fire disturbance and the snow season in the western Arctic, 2003–2100

Science.gov (United States)

Euskirchen, E.S.; McGuire, A. David; Rupp, T.S.; Chapin, F. S.; Walsh, J.E.

2009-01-01

In high latitudes, changes in climate impact fire regimes and snow cover duration, altering the surface albedo and the heating of the regional atmosphere. In the western Arctic, under four scenarios of future climate change and future fire regimes (2003–2100), we examined changes in surface albedo and the related changes in regional atmospheric heating due to: (1) vegetation changes following a changing fire regime, and (2) changes in snow cover duration. We used a spatially explicit dynamic vegetation model (Alaskan Frame-based Ecosystem Code) to simulate changes in successional dynamics associated with fire under the future climate scenarios, and the Terrestrial Ecosystem Model to simulate changes in snow cover. Changes in summer heating due to the changes in the forest stand age distributions under future fire regimes showed a slight cooling effect due to increases in summer albedo (mean across climates of −0.9 W m−2 decade−1). Over this same time period, decreases in snow cover (mean reduction in the snow season of 4.5 d decade−1) caused a reduction in albedo, and a heating effect (mean across climates of 4.3 W m−2 decade−1). Adding both the summer negative change in atmospheric heating due to changes in fire regimes to the positive changes in atmospheric heating due to changes in the length of the snow season resulted in a 3.4 W m−2 decade−1 increase in atmospheric heating. These findings highlight the importance of gaining a better understanding of the influences of changes in surface albedo on atmospheric heating due to both changes in the fire regime and changes in snow cover duration.

Electrocutaneous sensitivity: effects of skin temperature.

Science.gov (United States)

Larkin, W D; Reilly, J P

1986-01-01

The effect of human skin temperature on electrocutaneous sensitivity was examined using brief capacitive discharges. Stimuli were designed to ensure that sensory effects would be independent of skin resistance and would reflect underlying neural excitability as closely as possible. Skin temperature was manipulated by immersing the forearm in circulating hot or cold air. Detection thresholds on the arm and fingertip were raised by cooling, but were not altered by heating. Temperature-related sensitivity shifts were described by the same multiplicative factors for both threshold and suprathreshold levels. The temperature coefficient (Q10) for cutaneous sensitivity under these conditions was approximately 1.3.

Skin moisturization mechanisms: new data.

Science.gov (United States)

Bonté, F

2011-05-01

The main function of the skin is to protect the body against exogenous substances and excessive water loss. The skin barrier is located in the outermost layer of the skin, called the stratum corneum, which is composed of corneocytes, originating from the keratinocytes differentiation process, embedded in organized complex lipid domains. Moisturizing of the skin is recognized as the first anti-aging skin care. Skin moisturization is essential for its appearance, protection, complexion, softness and the reinforcement of its barrier properties against deleterious and exogenous environmental factors. The intrinsic water binding capacity of skin is not only due to the complex natural moisturizing factor present in corneocytes, but also to hyaluronic acid and a regulated water transport within the skin. Recent data shows that the water movements between the cells at the different levels of the epidermis are due to dedicated water and glycerol transport proteins named aquaporins. Their role in the skin moisturization is completed by corneodesmosomes and tight junctions. Water and pH are now shown to be of prime importance in the regulation of the epidermal enzymes linked to corneocytes desquamation and lipid synthesis. Furthermore, the level of moisturization of the skin is important in its protection against repeated exposure to various irritant agents or phenomena such as very frequent washing with strong tensioactive materials. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Self-cleaning skin-like prosthetic polymer surfaces

Science.gov (United States)

Simpson, John T [Clinton, TN; Ivanov, Ilia N [Knoxville, TN; Shibata, Jason [Manhattan Beach, CA

2012-03-27

An external covering and method of making an external covering for hiding the internal endoskeleton of a mechanical (e.g., prosthetic) device that exhibits skin-like qualities is provided. The external covering generally comprises an internal bulk layer in contact with the endoskeleton of the prosthetic device and an external skin layer disposed about the internal bulk layer. The external skin layer is comprised of a polymer composite with carbon nanotubes embedded therein. The outer surface of the skin layer has multiple cone-shaped projections that provide the external skin layer with superhydrophobicity. The carbon nanotubes are preferably vertically aligned between the inner surface and outer surface of the external skin layer in order to provide the skin layer with the ability to transmit heat. Superhydrophobic powders may optionally be used as part of the polymer composite or applied as a coating to the surface of the skin layer to enhance superhydrophobicity.

Skin Lesion Analysis towards Melanoma Detection Using Deep Learning Network

Science.gov (United States)

2018-01-01

Skin lesions are a severe disease globally. Early detection of melanoma in dermoscopy images significantly increases the survival rate. However, the accurate recognition of melanoma is extremely challenging due to the following reasons: low contrast between lesions and skin, visual similarity between melanoma and non-melanoma lesions, etc. Hence, reliable automatic detection of skin tumors is very useful to increase the accuracy and efficiency of pathologists. In this paper, we proposed two deep learning methods to address three main tasks emerging in the area of skin lesion image processing, i.e., lesion segmentation (task 1), lesion dermoscopic feature extraction (task 2) and lesion classification (task 3). A deep learning framework consisting of two fully convolutional residual networks (FCRN) is proposed to simultaneously produce the segmentation result and the coarse classification result. A lesion index calculation unit (LICU) is developed to refine the coarse classification results by calculating the distance heat-map. A straight-forward CNN is proposed for the dermoscopic feature extraction task. The proposed deep learning frameworks were evaluated on the ISIC 2017 dataset. Experimental results show the promising accuracies of our frameworks, i.e., 0.753 for task 1, 0.848 for task 2 and 0.912 for task 3 were achieved. PMID:29439500

Skin Lesion Analysis towards Melanoma Detection Using Deep Learning Network

Directory of Open Access Journals (Sweden)

Yuexiang Li

2018-02-01

Full Text Available Skin lesions are a severe disease globally. Early detection of melanoma in dermoscopy images significantly increases the survival rate. However, the accurate recognition of melanoma is extremely challenging due to the following reasons: low contrast between lesions and skin, visual similarity between melanoma and non-melanoma lesions, etc. Hence, reliable automatic detection of skin tumors is very useful to increase the accuracy and efficiency of pathologists. In this paper, we proposed two deep learning methods to address three main tasks emerging in the area of skin lesion image processing, i.e., lesion segmentation (task 1, lesion dermoscopic feature extraction (task 2 and lesion classification (task 3. A deep learning framework consisting of two fully convolutional residual networks (FCRN is proposed to simultaneously produce the segmentation result and the coarse classification result. A lesion index calculation unit (LICU is developed to refine the coarse classification results by calculating the distance heat-map. A straight-forward CNN is proposed for the dermoscopic feature extraction task. The proposed deep learning frameworks were evaluated on the ISIC 2017 dataset. Experimental results show the promising accuracies of our frameworks, i.e., 0.753 for task 1, 0.848 for task 2 and 0.912 for task 3 were achieved.

Skin Lesion Analysis towards Melanoma Detection Using Deep Learning Network.

Science.gov (United States)

Li, Yuexiang; Shen, Linlin

2018-02-11

Skin lesions are a severe disease globally. Early detection of melanoma in dermoscopy images significantly increases the survival rate. However, the accurate recognition of melanoma is extremely challenging due to the following reasons: low contrast between lesions and skin, visual similarity between melanoma and non-melanoma lesions, etc. Hence, reliable automatic detection of skin tumors is very useful to increase the accuracy and efficiency of pathologists. In this paper, we proposed two deep learning methods to address three main tasks emerging in the area of skin lesion image processing, i.e., lesion segmentation (task 1), lesion dermoscopic feature extraction (task 2) and lesion classification (task 3). A deep learning framework consisting of two fully convolutional residual networks (FCRN) is proposed to simultaneously produce the segmentation result and the coarse classification result. A lesion index calculation unit (LICU) is developed to refine the coarse classification results by calculating the distance heat-map. A straight-forward CNN is proposed for the dermoscopic feature extraction task. The proposed deep learning frameworks were evaluated on the ISIC 2017 dataset. Experimental results show the promising accuracies of our frameworks, i.e., 0.753 for task 1, 0.848 for task 2 and 0.912 for task 3 were achieved.

Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

Biophysical behavior of Scomberoides commersonianus skin collagen.

Science.gov (United States)

Kolli, Nagamalleswari; Joseph, K Thomas; Ramasami, T

2002-06-01

Some biophysical characteristics of the skin collagen from Scomberoides commersonianus were measured and compared to those of rat tail tendon. Stress-strain data indicate that the strain at break as well as the tensile strength of the fish skin without scales increased significantly. The maximum tension in case of rat skin is at least a factor of two higher than that observed in fish skin. The much lower hydrothermal isometric tension measurements observed in fish skin are attributable to a lesser number of heat stable crosslinks. Stress relaxation measurements in the fish skin indicate that more than one relaxation process may be involved in the stabilization of collagenous matrix. The observed differences in the biophysical behavior of fish skin may well arise from combination of changes in extent of hydroxylation of proline in collagen synthesis, hydrogen bond network and fibril orientation as compared to rat tail tendon.

Facial and Periorbital Cellulitis due to Skin Peeling with Jet Stream by an Unauthorized Person.

Science.gov (United States)

Kaptanoglu, Asli Feride; Mullaaziz, Didem; Suer, Kaya

2014-01-01

Technologies and devices for cosmetic procedures are developing with each passing day. However, increased and unauthorized use of such emerging technologies may also lead to increases in unexpected results and complications as well. Here, we report a case of facial cellulitis after a "beauty parlor" session of skin cleaning with jet stream peeling device in 19-year old female patient for the first time. Complications due to improper and unauthorized use of jet stream peeling devices may also cause doubts about the safety and impair the reputation of the technology as well. In order to avoid irreversible complications, local authorities should follow the technology and update the regulations where the dermatologists should take an active role.

Linear modeling of turbulent skin-friction reduction due to spanwise wall motion

Science.gov (United States)

Duque-Daza, Carlos; Baig, Mirza; Lockerby, Duncan; Chernyshenko, Sergei; Davies, Christopher; University of Warwick Team; Imperial College Team; Cardiff University Team

2012-11-01

We present a study on the effect of streamwise-travelling waves of spanwise wall velocity on the growth of near-wall turbulent streaks using a linearized formulation of the Navier-Stokes equations. The changes in streak amplification due to the travelling waves induced by the wall velocity are compared to published results of direct numerical simulation (DNS) predictions of the turbulent skin-friction reduction over a range of parameters; a clear correlation between these two sets of results is observed. Additional linearized simulations but at a much higher Reynolds numbers, more relevant to aerospace applications, produce results that show no marked differences to those obtained at low Reynolds number. It is also observed that a close correlation exists between DNS data of drag reduction and a very simple characteristic of the ``generalized'' Stokes layer generated by the streamwise-travelling waves. Carlos.Duque-Daza@warwick.ac.uk - School of Engineering, University of Warwick, Coventry CV4 7AL, UK caduqued@unal.edu.co - Department of Mechanical and Mechatronics Engineering, Universidad Nacional de Colombia.

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

Protection during production: Problems due to prevention? Nail and skin condition after prolonged wearing of occlusive gloves.

Science.gov (United States)

Weistenhöfer, Wobbeke; Uter, Wolfgang; Drexler, Hans

2017-01-01

Wearing of occlusive gloves during the whole working shift is considered a risk factor for developing hand eczema, similar to wet work. Moreover, the increased hydration due to glove occlusion may lead to brittle nails. Two hundred and seventy clean room workers, wearing occlusive gloves for prolonged periods, and 135 administrative employees not using gloves were investigated. This included a dermatological examination of the nails and the hands, using the Hand Eczema ScoRe for Occupational Screening (HEROS), measurement of transepidermal water loss (TEWL), and a standardized interview. Of the clean room workers, 39%, mainly women, reported nail problems, mostly brittle nails with onychoschisis. Skin score values showed no significant differences between HEROS values of both groups. TEWL values of exposed subjects were similar to TEWL values of controls 40 min after taking off the occlusive gloves. In a multiple linear regression analysis, male gender and duration of employment in the clean room were associated with a significant increase in TEWL values. The effect of occlusion on TEWL seems to be predominantly transient and not be indicative of a damaged skin barrier. This study confirmed the results of a previous investigation showing no serious adverse effect of wearing of occlusive gloves on skin condition without exposure to additional hazardous substances. However, occlusion leads to softened nails prone to mechanical injury. Therefore, specific prevention instructions are required to pay attention to this side effect of occlusion.

Temperature field due to time-dependent heat sources in a large rectangular grid - Derivation of analytical solution

International Nuclear Information System (INIS)

Claesson, J.; Probert, T.

1996-01-01

The temperature field in rock due to a large rectangular grid of heat releasing canisters containing nuclear waste is studied. The solution is by superposition divided into different parts. There is a global temperature field due to the large rectangular canister area, while a local field accounts for the remaining heat source problem. The global field is reduced to a single integral. The local field is also solved analytically using solutions for a finite line heat source and for an infinite grid of point sources. The local solution is reduced to three parts, each of which depends on two spatial coordinates only. The temperatures at the envelope of a canister are given by a single thermal resistance, which is given by an explicit formula. The results are illustrated by a few numerical examples dealing with the KBS-3 concept for storage of nuclear waste. 8 refs

Utilization of reconstructed cultured human skin models as an alternative skin for permeation studies of chemical compounds

OpenAIRE

Kano, Satoshi; 藤堂, 浩明; 杉江, 謙一; 藤本, 英哲; 中田, 圭一; 徳留, 嘉寛; 橋本, フミ惠; 杉林, 堅次

2010-01-01

Two reconstructed human skin models, EpiskinSM and EpiDermTM, have been approved as alternative membranes for skin corrosive/irritation experiments due to their close correlation with animal skin. Such reconstructed human skin models were evaluated as alternative membranes for skin permeation experiments. Seven drugs with different lipophilicities and almost the same molecular weight were used as test penetrants. Relationships were investigated between permeability coefficients (P values) of ...

A General Evaluation on Double Skin Facades

Directory of Open Access Journals (Sweden)

Tuğba İNAN

2014-05-01

Full Text Available This study examines the literature of double-skin facade systems over the last decade, and, with the help of tables and graphics, investigates their advantages and disadvantages. Moreover, a detailed comparison is made between double skin façade systems. The results of the study show that the greatest advantage (95% of double skin facade systems is their provision of natural ventilation. Other advantages are highlighted according to their percentage as follows: An increase in interaction between user and environment because of the high proportion of transparency, support of heat and sound insulation, reduction in heat transmission and solar heat gain coefficient, an increase in thermal comfort, allowance of solar control elements between the two facade spaces, and protection of these elements from external environment conditions. The most commonly accepted disadvantage (72% is overheating in the air space of the two facades. Other disadvantages are highlighted according to their percentage as follows: Problems related to a decrease in the amount of daylight entering the building, high investment costs, additional maintenance and repair costs, fire, and acoustic problems. In our country, architectural design decisions related to overheating must be taken so as to provide a positive contribution to energy performance and the applicability of these systems.

Safety of long-term subcutaneous free flap skin banking after skin-sparing mastectomy.

Science.gov (United States)

Verstappen, Ralph; Djedovic, Gabriel; Morandi, Evi Maria; Heiser, Dietmar; Rieger, Ulrich Michael; Bauer, Thomas

2018-03-01

A persistent problem in autologous breast reconstruction in skin-sparing mastectomies is skin restoration after skin necrosis or secondary oncological resection. As a solution to facilitate reconstruction, skin banking of free-flap skin has been proposed in cases where the overlying skin envelope must be resected, as this technique spares the patient an additional donor site. Herein, we present the largest series to date in which this method was used. We investigated its safety and the possibility of skin banking for prolonged periods of time. All skin-sparing mastectomies and immediate autologous breast reconstructions from December 2009 until June 2013 at our institution were analysed. We identified 31 patients who underwent 33 free flap reconstructions in which skin banking was performed. Our median skin banking period was 7 days, with a maximum duration of 171 days. In 22.5% of cases, the banked skin was used to reconstruct overlying skin defects, and in 9.6% of cases to reconstruct the nipple-areolar complex. Microbiological and histological investigations of the banked skin revealed neither clinical infections nor malignancies. In situ skin banking, even for prolonged periods of time, is a safe and cost-effective method to ensure that skin defects due to necrosis or secondary oncological resection can be easily reconstructed.

Shelf-life evaluation of bilayered human skin equivalent, MyDerm™.

Directory of Open Access Journals (Sweden)

Wan Tai Seet

Full Text Available Skin plays an important role in defense against infection and other harmful biological agents. Due to its fragile structure, skin can be easily damaged by heat, chemicals, traumatic injuries and diseases. An autologous bilayered human skin equivalent, MyDerm™, was engineered to provide a living skin substitute to treat critical skin loss. However, one of the disadvantages of living skin substitute is its short shelf-life, hence limiting its distribution worldwide. The aim of this study was to evaluate the shelf-life of MyDerm™ through assessment of cell morphology, cell viability, population doubling time and functional gene expression levels before transplantation. Skin samples were digested with 0.6% Collagenase Type I followed by epithelial cells dissociation with TrypLE Select. Dermal fibroblasts and keratinocytes were culture-expanded to obtain sufficient cells for MyDerm™ construction. MyDerm™ was constructed with plasma-fibrin as temporary biomaterial and evaluated at 0, 24, 48 and 72 hours after storage at 4°C for its shelf-life determination. The morphology of skin cells derived from MyDerm™ remained unchanged across storage times. Cells harvested from MyDerm™ after storage appeared in good viability (90.5%±2.7% to 94.9%±1.6% and had short population doubling time (58.4±8.7 to 76.9±19 hours. The modest drop in cell viability and increased in population doubling time at longer storage duration did not demonstrate a significant difference. Gene expression for CK10, CK14 and COL III were also comparable between different storage times. In conclusion, MyDerm™ can be stored in basal medium at 4°C for at least 72 hours before transplantation without compromising its functionality.

Shelf-life evaluation of bilayered human skin equivalent, MyDerm™.

Science.gov (United States)

Seet, Wan Tai; Manira, Maarof; Maarof, Manira; Khairul Anuar, Khairoji; Chua, Kien-Hui; Ahmad Irfan, Abdul Wahab; Ng, Min Hwei; Aminuddin, Bin Saim; Ruszymah, Bt Hj Idrus

2012-01-01

Skin plays an important role in defense against infection and other harmful biological agents. Due to its fragile structure, skin can be easily damaged by heat, chemicals, traumatic injuries and diseases. An autologous bilayered human skin equivalent, MyDerm™, was engineered to provide a living skin substitute to treat critical skin loss. However, one of the disadvantages of living skin substitute is its short shelf-life, hence limiting its distribution worldwide. The aim of this study was to evaluate the shelf-life of MyDerm™ through assessment of cell morphology, cell viability, population doubling time and functional gene expression levels before transplantation. Skin samples were digested with 0.6% Collagenase Type I followed by epithelial cells dissociation with TrypLE Select. Dermal fibroblasts and keratinocytes were culture-expanded to obtain sufficient cells for MyDerm™ construction. MyDerm™ was constructed with plasma-fibrin as temporary biomaterial and evaluated at 0, 24, 48 and 72 hours after storage at 4°C for its shelf-life determination. The morphology of skin cells derived from MyDerm™ remained unchanged across storage times. Cells harvested from MyDerm™ after storage appeared in good viability (90.5%±2.7% to 94.9%±1.6%) and had short population doubling time (58.4±8.7 to 76.9±19 hours). The modest drop in cell viability and increased in population doubling time at longer storage duration did not demonstrate a significant difference. Gene expression for CK10, CK14 and COL III were also comparable between different storage times. In conclusion, MyDerm™ can be stored in basal medium at 4°C for at least 72 hours before transplantation without compromising its functionality.

Heat Transfer in Metal Foam Heat Exchangers at High Temperature

Science.gov (United States)

Hafeez, Pakeeza

Heat transfer though open-cell metal foam is experimentally studied for heat exchanger and heat shield applications at high temperatures (˜750°C). Nickel foam sheets with pore densities of 10 and 40 pores per linear inch (PPI), have been used to make the heat exchangers and heat shields by using thermal spray coating to deposit an Inconel skin on a foam core. Heat transfer measurements were performed on a test rig capable of generating hot gas up to 1000°C. The heat exchangers were tested by exposing their outer surface to combustion gases at a temperature of 550°C and 750°C while being cooled by air flowing through them at room temperature at velocities up to 5 m/s. The temperature rise of the air, the surface temperature of the heat exchangers and the air temperature inside the heat exchanger were measured. The volumetric heat transfer coefficient and Nusselt number were calculated for different velocities. The heat transfer performance of the 40PPI sample brazed with the foil is found to be the most efficient. Pressure drop measurements were also performed for 10 and 40PPI metal foam. Thermographic measurements were done on 40PPI foam heat exchangers using a high temperature infrared camera. A high power electric heater was used to produce hot air at 300°C that passed over the foam heat exchanger while the cooling air was blown through it. Heat shields were made by depositing porous skins on metal foam and it was observed that a small amount of coolant leaking through the pores notably reduces the heat transfer from the hot gases. An analytical model was developed based assuming local thermal non-equilibrium that accounts for the temperature difference between solid and fluid phase. The experimental results are found to be in good agreement with the predicted values of the model.

A study on the flow field and local heat transfer performance due to geometric scaling of centrifugal fans

International Nuclear Information System (INIS)

Stafford, Jason; Walsh, Ed; Egan, Vanessa

2011-01-01

Highlights: ► Velocity field and local heat transfer trends of centrifugal fans. ► Time-averaged vortices are generated by flow separation. ► Local vortex and impingement regions are evident on surface heat transfer maps. ► Miniature centrifugal fans should be designed with an aspect ratio below 0.3. ► Theory under predicts heat transfer due to complex, unsteady outlet flow. - Abstract: Scaled versions of fan designs are often chosen to address thermal management issues in space constrained applications. Using velocity field and local heat transfer measurement techniques, the thermal performance characteristics of a range of geometrically scaled centrifugal fan designs have been investigated. Complex fluid flow structures and surface heat transfer trends due to centrifugal fans were found to be common over a wide range of fan aspect ratios (blade height to fan diameter). The limiting aspect ratio for heat transfer enhancement was 0.3, as larger aspect ratios were shown to result in a reduction in overall thermal performance. Over the range of fans examined, the low profile centrifugal designs produced significant enhancement in thermal performance when compared to that predicted using classical laminar flow theory. The limiting non-dimensional distance from the fan, where this enhancement is no longer apparent, has also been determined. Using the fundamental information inferred from local velocity field and heat transfer measurements, selection criteria can be determined for both low and high power practical applications where space restrictions exist.

Estimation of core body temperature from skin temperature, heat flux, and heart rate using a Kalman filter.

Science.gov (United States)

Welles, Alexander P; Xu, Xiaojiang; Santee, William R; Looney, David P; Buller, Mark J; Potter, Adam W; Hoyt, Reed W

2018-05-18

Core body temperature (T C ) is a key physiological metric of thermal heat-strain yet it remains difficult to measure non-invasively in the field. This work used combinations of observations of skin temperature (T S ), heat flux (HF), and heart rate (HR) to accurately estimate T C using a Kalman Filter (KF). Data were collected from eight volunteers (age 22 ± 4 yr, height 1.75 ± 0.10 m, body mass 76.4 ± 10.7 kg, and body fat 23.4 ± 5.8%, mean ± standard deviation) while walking at two different metabolic rates (∼350 and ∼550 W) under three conditions (warm: 25 °C, 50% relative humidity (RH); hot-humid: 35 °C, 70% RH; and hot-dry: 40 °C, 20% RH). Skin temperature and HF data were collected from six locations: pectoralis, inner thigh, scapula, sternum, rib cage, and forehead. Kalman filter variables were learned via linear regression and covariance calculations between T C and T S , HF, and HR. Root mean square error (RMSE) and bias were calculated to identify the best performing models. The pectoralis (RMSE 0.18 ± 0.04 °C; bias -0.01 ± 0.09 °C), rib (RMSE 0.18 ± 0.09 °C; bias -0.03 ± 0.09 °C), and sternum (RMSE 0.20 ± 0.10 °C; bias -0.04 ± 0.13 °C) were found to have the lowest error values when using T S , HF, and HR but, using only two of these measures provided similar accuracy. Copyright © 2018. Published by Elsevier Ltd.

Observation of bulk-ion heating in a tokamak plasma by application of positive and negative current pulses in TRIAM-1

Energy Technology Data Exchange (ETDEWEB)

Toi, K; Hiraki, N; Nakamura, K; Mitarai, O; Kawai, Y; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1980-09-01

A positive of negative current pulse induced by a pulsed toroidal electric field much higher than the Dreicer field increases the bulk-ion temperature of the plasma centre two to three times, without macroscopic plasma destruction. The decay time of the raised ion temperature agrees well with the prediction from neoclassical transport theory. The magnitude of the positive current pulse is limited by violent current disruption, and that of the negative current by a lack of MHD equilibrium which is due to a marked reduction of the total plasma current. The relevant current-driven instabilities in the turbulent heating of a tokamak plasma, skin heating and inward transfer of the energy deposition in the skin layer are briefly discussed.

Facial and Periorbital Cellulitis due to Skin Peeling with Jet Stream by an Unauthorized Person

Directory of Open Access Journals (Sweden)

Asli Feride Kaptanoglu

2014-01-01

Full Text Available Technologies and devices for cosmetic procedures are developing with each passing day. However, increased and unauthorized use of such emerging technologies may also lead to increases in unexpected results and complications as well. Here, we report a case of facial cellulitis after a “beauty parlor” session of skin cleaning with jet stream peeling device in 19-year old female patient for the first time. Complications due to improper and unauthorized use of jet stream peeling devices may also cause doubts about the safety and impair the reputation of the technology as well. In order to avoid irreversible complications, local authorities should follow the technology and update the regulations where the dermatologists should take an active role.

Scaling of heat transfer augmentation due to mechanical distortions in hypervelocity boundary layers

Science.gov (United States)

Flaherty, W.; Austin, J. M.

2013-10-01

We examine the response of hypervelocity boundary layers to global mechanical distortions due to concave surface curvature. Surface heat transfer and visual boundary layer thickness data are obtained for a suite of models with different concave surface geometries. Results are compared to predictions using existing approximate methods. Near the leading edge, good agreement is observed, but at larger pressure gradients, predictions diverge significantly from the experimental data. Up to a factor of five underprediction is reported in regions with greatest distortion. Curve fits to the experimental data are compared with surface equations. We demonstrate that reasonable estimates of the laminar heat flux augmentation may be obtained as a function of the local turning angle for all model geometries, even at the conditions of greatest distortion. This scaling may be explained by the application of Lees similarity. As a means of introducing additional local distortions, vortex generators are used to impose streamwise structures into the boundary layer. The response of the large scale vortices to an adverse pressure gradient is investigated. Surface streak evolution is visualized over the different surface geometries using fast response pressure sensitive paint. For a flat plate baseline case, heat transfer augmentation at similar levels to turbulent flow is measured. For the concave geometries, increases in heat transfer by factors up to 2.6 are measured over the laminar values. The scaling of heat transfer with turning angle that is identified for the laminar boundary layer response is found to be robust even in the presence of the imposed vortex structures.

Modeling of Heat Transfer and Ablation of Refractory Material Due to Rocket Plume Impingement

Science.gov (United States)

Harris, Michael F.; Vu, Bruce T.

2012-01-01

CR Tech's Thermal Desktop-SINDA/FLUINT software was used in the thermal analysis of a flame deflector design for Launch Complex 39B at Kennedy Space Center, Florida. The analysis of the flame deflector takes into account heat transfer due to plume impingement from expected vehicles to be launched at KSC. The heat flux from the plume was computed using computational fluid dynamics provided by Ames Research Center in Moffet Field, California. The results from the CFD solutions were mapped onto a 3-D Thermal Desktop model of the flame deflector using the boundary condition mapping capabilities in Thermal Desktop. The ablation subroutine in SINDA/FLUINT was then used to model the ablation of the refractory material.

Simple Theory of Thermal Fatigue Caused by RF Pulse Heating

CERN Document Server

Kuzikov, S

2004-01-01

The projects of electron-positron linear colliders imply that accelerating structures and other RF components will undergo action of extremely high RF fields. Except for breakdown threat there is an effect of the damage due to multi-pulse mechanical stress caused by Ohmic heating of the skin layer. A new theory of the thermal fatigue is considered. The theory is based on consideration of the quasi-elastic interaction between neighbor grains of metal due to the expansion of the thermal skin-layer. The developed theory predicts a total number of the RF pulses needed for surface degradation in dependence on temperature rise, pulse duration, and average temperature. The unknown coefficients in the final formula were found, using experimental data obtained at 11.4 GHz for the copper. In order to study the thermal fatigue at higher frequencies and to compare experimental and theoretical results, the experimental investigation of degradation of the copper cavity exposed to 30 GHz radiation is carried out now, basing...

Heating Augmentation Due to Compression Pad Cavities on the Project Orion CEV Heat Shield

Science.gov (United States)

Hollis, Brian R.

2009-01-01

An experimental study has been conducted to assess the effects of compression pad cavities on the aeroheating environment of the Project Orion CEV heat-shield. Testing was conducted in Mach 6 and Mach 10 perfect-gas wind tunnels to obtain heating measurements in and around the compression pads cavities using global phosphor thermography. Data were obtained over a wide range of Reynolds numbers that produced laminar, transitional, and turbulent flow within and downstream of the cavities. The effects of cavity dimensions on boundary-layer transition and heating augmentation levels were studied. Correlations were developed for transition onset and for the average cavity-heating augmentation.

Solutions to mitigate heat loads due to electrons on sensitive components of ITER HNB beamlines

Energy Technology Data Exchange (ETDEWEB)

Sartori, Emanuele, E-mail: emanuele.sartori@gmail.com [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova (Italy); Veltri, Pierluigi; Dalla Palma, Mauro; Agostinetti, Piero [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova (Italy); Hemsworth, Ronald; Singh, Mahendrajit [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Serianni, Gianluigi [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), C.so Stati Uniti 4, 35127 Padova (Italy)

2016-11-01

Highlights: • Energetic electrons leaking out of the ITER HNB accelerator are simulated. • Electrons generated along the ITER HNB beamline are simulated. • Heat loads and heat load maps on cryopumps are calculated for ITER HNB and test facility. • Protection solutions that will be installed are presented and their effect discussed. - Abstract: The operation of neutral beam injectors for plasma heating and current drive in a fusion device provides challenges in the thermal management of beamline components. Sensitive components such as the cryogenic pumps at beamline periphery shall be protected from the heat flux due to stray electrons. These are emitted by the negative ion accelerator or generated along the beamline by interaction of fast electrons, ions or atoms with background gas and surfaces. In this article the case of the ITER Heating Neutral Beam (HNB) and its test facility MITICA is discussed, for which the beam parameters and the required pulse length of one hour is a major leap forward with respect to the present experience with neutral beam systems. The engineering solutions adopted for effective cryopump protection against the heat load from electrons are described. The use of three-dimensional numerical simulations of particle trajectories in the complex geometry of the beamline was needed for the quantitative estimations of the heat loads. The presented solutions were optimized to minimize the impact on gas pumping and on the functionality of other components.

Differences in response to heat stress due to production level and breed of dairy cows

Science.gov (United States)

Gantner, Vesna; Bobic, Tina; Gantner, Ranko; Gregic, Maja; Kuterovac, Kresimir; Novakovic, Jurica; Potocnik, Klemen

2017-09-01

The climatic conditions in Croatia are deteriorating which significantly increases the frequency of heat stress. This creates a need for an adequate dairy farming strategy. The impact of heat stress can be reduced in many ways, but the best long-term solution includes the genetic evaluation and selection for heat stress resistance. In order to create the basis for genetic evaluation, this research determined the variation in daily milk yield (DMY) and somatic cell count (SCC) as well as the differences in resistance to heat stress due to production level (high, low) and breed (Holstein, Simmental) of dairy cattle breed in Croatia. For statistical analysis, 1,070,554 test-day records from 70,135 Holsteins reared on 5679 farms and 1,300,683 test-day records from 86,013 Simmentals reared on 8827 farms in Croatia provided by the Croatian Agricultural Agency were used. The results of this research indicate that the high-producing cows are much more susceptible to heat stress than low-producing especially Holsteins. Also, the results of this research indicate that Simmental breed, in terms of daily milk production and somatic cell count, could be more resistant to heat stress than Holstein. The following research should determine whether Simmentals are genetically more appropriate for the challenges that are in store for the future milk production in this region. Furthermore, could an adequate production level be achieved with Simmentals by maintaining the heat resistance?

FDTD analysis of temperature elevation in the lens of human and rabbit models due to near-field and far-field exposures at 2.45 GHz

International Nuclear Information System (INIS)

Oizumi, T.; Laakso, I.; Hirata, A.; Fujiwara, O.; Watanabe, S.; Taki, M.; Kojima, M.; Sasaki, H.; Sasaki, K.

2013-01-01

The eye is said to be one of the most sensitive organs to microwave heating. According to previous studies, the possibility of microwave-induced cataract formation has been experimentally investigated in rabbit and monkey eyes, but not for the human eye due to ethical reasons. In the present study, the temperature elevation in the lens, the skin around the eye and the core temperature of numerical human and rabbit models for far-field and near-field exposures at 2.45 GHz are investigated. The temperature elevations in the human and rabbit models were compared with the threshold temperatures for inducing cataracts, thermal pain in the skin and reversible health effects such as heat exhaustion or heat stroke. For plane-wave exposure, the core temperature elevation is shown to be essential both in the human and in the rabbit models as suggested in the international guidelines and standards. For localised exposure of the human eye, the temperature elevation of the skin was essential, and the lens temperature did not reach its threshold for thermal pain. On the other hand, the lens temperature elevation was found to be dominant for the rabbit eye. (authors)

FDTD analysis of temperature elevation in the lens of human and rabbit models due to near-field and far-field exposures at 2.45 GHz.

Science.gov (United States)

Oizumi, Takuya; Laakso, Ilkka; Hirata, Akimasa; Fujiwara, Osamu; Watanabe, Soichi; Taki, Masao; Kojima, Masami; Sasaki, Hiroshi; Sasaki, Kazuyuki

2013-07-01

The eye is said to be one of the most sensitive organs to microwave heating. According to previous studies, the possibility of microwave-induced cataract formation has been experimentally investigated in rabbit and monkey eyes, but not for the human eye due to ethical reasons. In the present study, the temperature elevation in the lens, the skin around the eye and the core temperature of numerical human and rabbit models for far-field and near-field exposures at 2.45 GHz are investigated. The temperature elevations in the human and rabbit models were compared with the threshold temperatures for inducing cataracts, thermal pain in the skin and reversible health effects such as heat exhaustion or heat stroke. For plane-wave exposure, the core temperature elevation is shown to be essential both in the human and in the rabbit models as suggested in the international guidelines and standards. For localised exposure of the human eye, the temperature elevation of the skin was essential, and the lens temperature did not reach its threshold for thermal pain. On the other hand, the lens temperature elevation was found to be dominant for the rabbit eye.

Safety of long-term subcutaneous free flap skin banking after skin-sparing mastectomy

Directory of Open Access Journals (Sweden)

Ralph Verstappen

2018-03-01

Full Text Available Background A persistent problem in autologous breast reconstruction in skin-sparing mastectomies is skin restoration after skin necrosis or secondary oncological resection. As a solution to facilitate reconstruction, skin banking of free-flap skin has been proposed in cases where the overlying skin envelope must be resected, as this technique spares the patient an additional donor site. Herein, we present the largest series to date in which this method was used. We investigated its safety and the possibility of skin banking for prolonged periods of time. Methods All skin-sparing mastectomies and immediate autologous breast reconstructions from December 2009 until June 2013 at our institution were analysed. Results We identified 31 patients who underwent 33 free flap reconstructions in which skin banking was performed. Our median skin banking period was 7 days, with a maximum duration of 171 days. In 22.5% of cases, the banked skin was used to reconstruct overlying skin defects, and in 9.6% of cases to reconstruct the nipple-areolar complex. Microbiological and histological investigations of the banked skin revealed neither clinical infections nor malignancies. Conclusions In situ skin banking, even for prolonged periods of time, is a safe and cost-effective method to ensure that skin defects due to necrosis or secondary oncological resection can be easily reconstructed.

Advances in the optimisation of apparel heating products: A numerical approach to study heat transport through a blanket with an embedded smart heating system

International Nuclear Information System (INIS)

Neves, S.F.; Couto, S.; Campos, J.B.L.M.; Mayor, T.S.

2015-01-01

The optimisation of the performance of products with smart/active functionalities (e. g. in protective clothing, home textiles products, automotive seats, etc.) is still a challenge for manufacturers and developers. The aim of this study was to optimise the thermal performance of a heating product by a numerical approach, by analysing several opposing requirements and defining solutions for the identified limitations, before the construction of the first prototype. A transfer model was developed to investigate the transport of heat from the skin to the environment, across a heating blanket with an embedded smart heating system. Several parameters of the textile material and of the heating system were studied, in order to optimise the thermal performance of the heating blanket. Focus was put on the effects of thickness and thermal conductivity of each layer, and on parameters associated with the heating elements, e.g. position of the heating wires relative to the skin, distance between heating wires, applied heating power, and temperature range for operation of the heating system. Furthermore, several configurations of the blanket (and corresponding heating powers) were analysed in order to minimise the heat loss from the body to the environment, and the temperature distribution along the skin. The results show that, to ensure an optimal compromise between the thermal performance of the product and the temperature oscillation along its surface, the distance between the wires should be small (and not bigger than 50 mm), and each layer of the heating blanket should have a specific thermal resistance, based on the expected external conditions during use and the requirements of the heating system (i.e. requirements regarding energy consumption/efficiency and capacity to effectively regulate body exchanges with surrounding environment). The heating system should operate in an ON/OFF mode based on the body heating needs and within a temperature range specified based on

A study on the flow field and local heat transfer performance due to geometric scaling of centrifugal fans

Energy Technology Data Exchange (ETDEWEB)

Stafford, Jason, E-mail: jason.stafford@ul.ie [Stokes Institute, Mechanical, Aeronautical and Biomedical Engineering Department, University of Limerick, Limerick (Ireland); Walsh, Ed; Egan, Vanessa [Stokes Institute, Mechanical, Aeronautical and Biomedical Engineering Department, University of Limerick, Limerick (Ireland)

2011-12-15

Highlights: Black-Right-Pointing-Pointer Velocity field and local heat transfer trends of centrifugal fans. Black-Right-Pointing-Pointer Time-averaged vortices are generated by flow separation. Black-Right-Pointing-Pointer Local vortex and impingement regions are evident on surface heat transfer maps. Black-Right-Pointing-Pointer Miniature centrifugal fans should be designed with an aspect ratio below 0.3. Black-Right-Pointing-Pointer Theory under predicts heat transfer due to complex, unsteady outlet flow. - Abstract: Scaled versions of fan designs are often chosen to address thermal management issues in space constrained applications. Using velocity field and local heat transfer measurement techniques, the thermal performance characteristics of a range of geometrically scaled centrifugal fan designs have been investigated. Complex fluid flow structures and surface heat transfer trends due to centrifugal fans were found to be common over a wide range of fan aspect ratios (blade height to fan diameter). The limiting aspect ratio for heat transfer enhancement was 0.3, as larger aspect ratios were shown to result in a reduction in overall thermal performance. Over the range of fans examined, the low profile centrifugal designs produced significant enhancement in thermal performance when compared to that predicted using classical laminar flow theory. The limiting non-dimensional distance from the fan, where this enhancement is no longer apparent, has also been determined. Using the fundamental information inferred from local velocity field and heat transfer measurements, selection criteria can be determined for both low and high power practical applications where space restrictions exist.

Segmented phantoms reconstruction for skin dosimetry

International Nuclear Information System (INIS)

Antunes, Paula C.G.; Siqueira, Paulo T.D.; Yoriyaz, Helio; Fonseca, Gabriel P.; Furnari, Laura; Reis, Gabriela S.

2009-01-01

There are several radio-sensitive skin diseases. Skin dosimetry is a difficult task to be properly performed, not only due to skin extension and small thickness, but also because it is usually submitted to high dose gradients. High-resolution medical images along with methods that simulate the interaction of radiation with matter, as the Monte Carlo radiation transport codes, have been widely used in medical physics procedures. These images provide the construction of realistic computational anatomical models, which after being coupled to these codes, retrieve reliable dosimetric assessments. However, present day regular images are unsuitable to correctly perform skin dose distribution evaluations. This inability is due to improper skin discrimination in most of current medical images, once its thickness stands below image resolution, i.e. pixel characteristic sizes are larger than skin thickness. This paper proposes a methodology of voxelized phantom reconstruction and segmentation, by subdividing their basic elements - voxels. It is done in order to better discriminate the skin by assigning more adequate value for skin thickness and its actual localization. Aiming at a more realistic skin modeling one is expected to get more accurate skin dose evaluations. This task is an important issue in many radiotherapy procedures. A particular interest lays in Total Skin Electron Therapy (TSET), which highlights the treatment of the whole body irradiation, a radiotherapy procedure under implementation in the Hospital das Clinicas da Universidade de Sao Paulo (HC-USP). (author)

Biologic changes due to long-wave ultraviolet irradiation on human skin: ultrastructural study

International Nuclear Information System (INIS)

Kumakiri, M.; Hashimoto, K.; Willis, I.

1977-01-01

Alteration of the skin induced by single and repeated long-wave ultraviolet (UVA) exposures was studied. Following a single exposure to relatively large doses of UVA, pronounced dermal damage was observed. In the papillary dermis, superficial dermal vessels showed widely open endothelial gaps and extravasation of blood cells. Marked changes of fibroblasts were also seen in the superficial dermis. In the reticular dermis, extravascular fibrin deposition was seen. After repeated exposures to UVA the formation of cross-banded filamentous aggregations (''Zebra bodies'') was observed in the superficial and reticular dermis. These were often found in amorphous masses surrounding the blood vessels. These striking dermal alterations were absent in skin irradiated by solar stimulating radiation and in control skin. Dyskeratotic ''sunburn cells'' were occasionally seen in the epidermis after single as well as repeated exposures to UVA. The number of these cells was less than that seen after a single exposure to solar simulating radiation

In Vitro Drug Transfer Due to Drug Retention in Human Epidermis Pretreated with Application of Marketed Estradiol Transdermal Systems.

Science.gov (United States)

Krishnaiah, Yellela S R; Pavurala, Naresh; Yang, Yang; Manda, Prashanth; Katragadda, Usha; Yang, Yongsheng; Shah, Rakhi; Fang, Guodong; Khan, Mansoor A

2017-08-01

Study objective was to assess skin-to-skin drug transfer potential that may occur due to drug retention in human epidermis (DRE) pretreated with application of estradiol transdermal drug delivery systems (TDDS) and other estradiol transdermal dosage forms (gels and sprays). TDDS (products-A, B, and C) with varying formulation design and composition, and other estradiol transdermal products (gel and spray) were applied to heat separated human epidermis (HSE) and subjected to in vitro drug permeation study. Amounts of DRE were quantified after 24 h. The DRE with product-B was significantly (P  0.05) amounts of DRE. A separate in vitro permeation study was carried out to determine amounts of drug transferred from drug-retaining epidermis to untreated HSE. The amounts of drug transferred, due to DRE after 8 h, with product-C were significantly (P drug transfer due to the DRE after labeled period of using estradiol TDDS, though the clinical relevance of these findings is yet to be determined.

A review of heat transfer phenomena and the impact of moisture on firefighters' clothing and protection.

Science.gov (United States)

Morel, Aude; Bedek, Gauthier; Salaün, Fabien; Dupont, Daniel

2014-01-01

Protective clothing with high insulation properties helps to keep the wearer safe from flames and other types of hazards. Such protection presents some drawbacks since it hinders movement and decreases comfort, in particular due to heat stress. In fact, sweating causes the accumulation of moisture which directly influences firefighters' performance, decreasing protection due to the increase in radiant heat flux. Vaporisation and condensation of hot moisture also induces skin burn. To evaluate the heat protection of protective clothing, Henrique's equation is used to predict the time leading to second-degree burn. The influence of moisture on protection is complex, i.e., at low radiant heat flux, an increase in moisture content increases protection, and also changes thermal properties. Better understanding of heat and mass transfer in protective clothing is required to develop enhanced protection and to prevent burn injuries. This paper aims to contribute to a better understanding of heat and mass transfer inside firefighters' protective clothing to enhance safety. The focus is on the influence of moisture content and the prevention of steam burn.

Gamma ray heating rates due to chromium isotopes in stellar core during late stages of high mass stars (>10M⊙

Directory of Open Access Journals (Sweden)

Nabi Jameel-Un

2017-01-01

Full Text Available Gamma ray heating rates are thought to play a crucial role during the pre-supernova stage of high mass stars. Gamma ray heating rates, due to β±-decay and electron (positron capture on chromium isotopes, are calculated using proton-neutron quasiparticle random phase approximation theory. The electron capture significantly affects the lepton fraction (Ye and accelerates the core contraction. The gamma rays emitted as a result of weak processes heat the core and tend to hinder the cooling and contraction due to electron capture and neutrino emission. The emitted gamma rays tend to produce enormous entropy and set the convection to play its role at this stage. The gamma heating rates, on 50-60Cr, are calculated for the density range 10 < ρ (g.cm-3 < 1011 and temperature range 107 < T (K < 3.0×1010.

Heat-Related Illnesses

Medline Plus

Full Text Available ... moist, pale skin, rapid pulse, elevated or lowered blood pressure, nausea, loss of consciousness, vomiting or a high body temperature. For late stage heat stroke symptoms, cool the person further by positioning ...

Entropy Generation Due to Natural Convection in a Partially Heated Cavity by Local RBF-DQ Method

DEFF Research Database (Denmark)

Soleimani, S.; Qajarjazi, A.; Bararnia, H.

2011-01-01

The Local Radial Basis Function-Differential Quadrature (RBF-DQ) method is applied to twodimensional incompressible Navier-Stokes equations in primitive form. Numerical results of heatlines and entropy generation due to heat transfer and fluid friction have been obtained for laminar natural...

A Phase 3, Randomized, Double-Blind, Multicenter Study To Evaluate the Safety and Efficacy of Intravenous Iclaprim versus Vancomycin for Treatment of Acute Bacterial Skin and Skin Structure Infections Suspected or Confirmed To Be Due to Gram-Positive Pathogens (REVIVE-2 Study).

Science.gov (United States)

Holland, Thomas L; O'Riordan, William; McManus, Alison; Shin, Elliot; Borghei, Ali; File, Thomas M; Wilcox, Mark H; Torres, Antoni; Dryden, Matthew; Lodise, Thomas; Oguri, Toyoko; Corey, G Ralph; McLeroth, Patrick; Shukla, Rajesh; Huang, David B

2018-05-01

Iclaprim is a novel diaminopyrimidine antibiotic that may be an effective and safe treatment for serious skin infections. The safety and effectiveness of iclaprim were assessed in a global phase 3, double-blind, randomized, active-controlled trial. Six hundred thirteen adults with acute bacterial skin and skin structure infections (ABSSSIs) suspected or confirmed to be due to Gram-positive pathogens were randomized to iclaprim (80 mg) or vancomycin (15 mg/kg of body weight), both of which were administered intravenously every 12 h for 5 to 14 days. The primary endpoint was a ≥20% reduction in lesion size compared with that at the baseline at 48 to 72 h after the start of administration of study drug in the intent-to-treat population. Among patients randomized to iclaprim, 78.3% (231 of 295) met this primary endpoint, whereas 76.7% (234 of 305) of those receiving vancomycin met this primary endpoint (difference, 1.58%; 95% confidence interval, -5.10% to 8.26%). This met the prespecified 10% noninferiority margin. Iclaprim was well tolerated, with most adverse events being categorized as mild. In conclusion, iclaprim was noninferior to vancomycin in this phase 3 clinical trial for the treatment of acute bacterial skin and skin structure infections. On the basis of these results, iclaprim may be an efficacious and safe treatment for skin infections suspected or confirmed to be due to Gram-positive pathogens. (This trial has been registered at ClinicalTrials.gov under identifier NCT02607618.). Copyright © 2018 American Society for Microbiology.

Transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations

International Nuclear Information System (INIS)

Sugano, Y.

1980-01-01

The transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations on two edges are studied by means of the Airy stress function. The purposes of this paper are to present a method of determing the transient thermal stresses in an orthographic rectangular plate with four edges of distinct thermal boundary condition of the third kind which exactly satisfy the traction-free conditions of shear stress over all boundaries including four corners of the plate, and to consider the effects of the anisotropies of material properties and the convective heat transfer on the upper and lower surfaces on the thermal stress distribution. (orig.)

Future heat waves due to climate change threaten the survival of Posidonia oceanica seedlings.

Science.gov (United States)

Guerrero-Meseguer, Laura; Marín, Arnaldo; Sanz-Lázaro, Carlos

2017-11-01

Extreme weather events are major drivers of ecological change, and their occurrence is likely to increase due to climate change. The transient increases in atmospheric temperatures are leading to a greater occurrence of heat waves, extreme events that can produce a substantial warming of water, especially in enclosed basins such as the Mediterranean Sea. Here, we tested the effects of current and predicted heat waves on the early stages of development of the seagrass Posidonia oceanica. Temperatures above 27 °C limited the growth of the plant by inhibiting its photosynthetic system. It suffered a reduction in leaf growth and faster leaf senescence, and in some cases mortality. This study demonstrates that the greater frequency of heat waves, along with anticipated temperature rises in coming decades, are expected to negatively affect the germination of P. oceanica seedlings. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Skin changes in `screen dermatitis` versus classical UV- and ionizing irradiation-related damage - similarities and differences

Energy Technology Data Exchange (ETDEWEB)

Gangi, S.; Johansson, O. [Karolinska Inst., Dept. of Neuroscience, Experimental Dermatology Unit, stockholm (Sweden)

1997-12-01

An increasing number of persons say that they get cutaneous problems as well as symptoms from certain internal organs, such as the central nervous system (CNS) and the heart, when being close to electric equipment. A major group of these patients are the users of video display terminals (VDTs), who claim to have subjective and objective skin- and mucosa-related symptoms, such as pain, itch, heat sensation, ery-therma, papules, and pustules. The CNS symptoms are, e.g. dizziness, tiredness, and headache. Erythema, itch, heat sensation, edema and pain are also common symptoms of sunburn (UV dermatitis). Alterations have been observed in cell populations of the skin of patients suffering from so-called `screen dermatitis` similar to those observed in the skin damaged due to ultraviolet (UV) light or ionizing radiation. In `screen dermatitis` patients a much higher number of mast cells have been observed. It is known that UVE irradiation induces mast cell degranulation and release of TNF-{alpha}. The high number of mast cells present in the `screen dermatitis` patients and the possible release of specific substances, such as histamine, may explain their clinical symptoms of itch, pain, edema and erythema. The most remarkable change among cutaneous cells, after exposure with the above-mentioned irradiation sources, is the disappearance of the Langerhans` cells. This change has also been observed in `screen dermatitis` patients, again pointing to a common cellular and molecular basis. The results of this literature study demonstrate that highly similar changes exist in the skin of `screen dermatitis` patients, as regard the clinical manifestations as well as alterations in the cell populations, and in skin damaged by UV light or ionizing radiation. (au) 93 refs.

Skin changes in 'screen dermatitis' versus classical UV- and ionizing irradiation-related damage - similarities and differences

International Nuclear Information System (INIS)

Gangi, S.; Johansson, O.

1997-01-01

An increasing number of persons say that they get cutaneous problems as well as symptoms from certain internal organs, such as the central nervous system (CNS) and the heart, when being close to electric equipment. A major group of these patients are the users of video display terminals (VDTs), who claim to have subjective and objective skin- and mucosa-related symptoms, such as pain, itch, heat sensation, ery-therma, papules, and pustules. The CNS symptoms are, e.g. dizziness, tiredness, and headache. Erythema, itch, heat sensation, edema and pain are also common symptoms of sunburn (UV dermatitis). Alterations have been observed in cell populations of the skin of patients suffering from so-called 'screen dermatitis' similar to those observed in the skin damaged due to ultraviolet (UV) light or ionizing radiation. In 'screen dermatitis' patients a much higher number of mast cells have been observed. It is known that UVE irradiation induces mast cell degranulation and release of TNF-α. The high number of mast cells present in the 'screen dermatitis' patients and the possible release of specific substances, such as histamine, may explain their clinical symptoms of itch, pain, edema and erythema. The most remarkable change among cutaneous cells, after exposure with the above-mentioned irradiation sources, is the disappearance of the Langerhans' cells. This change has also been observed in 'screen dermatitis' patients, again pointing to a common cellular and molecular basis. The results of this literature study demonstrate that highly similar changes exist in the skin of 'screen dermatitis' patients, as regard the clinical manifestations as well as alterations in the cell populations, and in skin damaged by UV light or ionizing radiation. (au)

Imaging mass spectrometry visualizes ceramides and the pathogenesis of dorfman-chanarin syndrome due to ceramide metabolic abnormality in the skin.

Directory of Open Access Journals (Sweden)

Naoko Goto-Inoue

Full Text Available Imaging mass spectrometry (IMS is a useful cutting edge technology used to investigate the distribution of biomolecules such as drugs and metabolites, as well as to identify molecular species in tissues and cells without labeling. To protect against excess water loss that is essential for survival in a terrestrial environment, mammalian skin possesses a competent permeability barrier in the stratum corneum (SC, the outermost layer of the epidermis. The key lipids constituting this barrier in the SC are the ceramides (Cers comprising of a heterogeneous molecular species. Alterations in Cer composition have been reported in several skin diseases that display abnormalities in the epidermal permeability barrier function. Not only the amounts of different Cers, but also their localizations are critical for the barrier function. We have employed our new imaging system, capable of high-lateral-resolution IMS with an atmospheric-pressure ionization source, to directly visualize the distribution of Cers. Moreover, we show an ichthyotic disease pathogenesis due to abnormal Cer metabolism in Dorfman-Chanarin syndrome, a neutral lipid storage disorder with ichthyosis in human skin, demonstrating that IMS is a novel diagnostic approach for assessing lipid abnormalities in clinical setting, as well as for investigating physiological roles of lipids in cells/tissues.

Characterising the variations in ethnic skin colours: a new calibrated data base for human skin.

Science.gov (United States)

Xiao, K; Yates, J M; Zardawi, F; Sueeprasan, S; Liao, N; Gill, L; Li, C; Wuerger, S

2017-02-01

Accurate skin colour measurements are important for numerous medical applications including the diagnosis and treatment of cutaneous disorders and the provision of maxillofacial soft tissue prostheses. In this study, we obtained accurate skin colour measurements from four different ethnic groups (Caucasian, Chinese, Kurdish, Thai) and at four different body locations (Forehead, cheek, inner arm, back of hand) with a view of establishing a new skin colour database for medical and cosmetic applications. Skin colours are measured using a spectrophotometer and converted to a device-independent standard colour appearance space (CIELAB) where skin colour is expressed as values along the three dimensions: Lightness L*, Redness a* and Yellowness b*. Skin colour differences and variation are then evaluated as a function of ethnicity and body location. We report three main results: (1) When plotted in a standard colour appearance space (CIELAB), skin colour distributions for the four ethnic groups overlap significantly, although there are systematic mean differences. Between ethnicities, the most significant skin colour differences occur along the yellowness dimension, with Thai skin exhibiting the highest yellowness (b*) value and Caucasian skin the lowest value. Facial redness (a*) is invariant across the four ethnic groups. (2) Between different body locations, there are significant variations in redness (a*), with the forehead showing the highest redness value and the inner arm the lowest. (3) The colour gamut is smallest in the Chinese sample and largest in the Caucasian sample, with the Chinese gamut lying entirely the Caucasian gamut. Similarly, the largest variability in skin tones is found in the Caucasian group, and the smallest in the Chinese group. Broadly speaking, skin colour variation can be explained by two main factors: individual differences in lightness and yellowness are mostly due to ethnicity, whereas differences in redness are primarily due to

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

Modeling ambipolar potential formation due to ICRF heating effects on electrons

International Nuclear Information System (INIS)

Johnson, J.W.; Callen, J.D.; Hershkowitz, N.

1985-08-01

A mechanism for the potential bump observed near the region of ICRF heating in the endplugs of the Phaedrus tandem mirror experiment is investigated by numerical simulation of electron orbits in a simple mirror geometry. Given initial magnetic and ambipolar potential wells that trap the electrons, the ''near field'' parallel electric field E-tilde/sub z/e/sup -iωt/, which is localized near and due to the ICRF heating, tends to eject electrons from the region where E-tilde/sub z/ is nonzero. This depletion of the local electron population causes a local increase in the ambipolar potential. The rate at which the electrons are ejected, (dn/dt), is calculated from the electron orbit computation for a given potential well depth. The rate at which passing particles ''fill in'' the potential well can also be calculated. An estimate of how large the bump in the ambipolar potential becomes is obtained by finding the well depth at which (dn/dt) approximately equals the ''filling'' rate. For Phaedrus parameters (n 0 approx. = 4.0 x 10 12 cm -3 , T/sub e/ = 20 eV, E-tilde/sub z/ approx. = 1.0 V/cm) the electron pumping rate balances the ''filling'' rate at a potential well depth of approximately 40 V, consistent with experimental results

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

Science.gov (United States)

Tsankov, N; Mateev, D; Darlenski, R

2018-03-01

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

Skin color and tissue thickness effects on transmittance, reflectance, and skin temperature when using 635 and 808 nm lasers in low intensity therapeutics.

Science.gov (United States)

Souza-Barros, Leanna; Dhaidan, Ghaith; Maunula, Mikko; Solomon, Vaeda; Gabison, Sharon; Lilge, Lothar; Nussbaum, Ethne L

2018-04-01

To examine the role of skin color and tissue thickness on transmittance, reflectance, and skin heating using red and infrared laser light. Forty volunteers were measured for skin color and skin-fold thickness at a standardized site near the elbow. Transmittance, reflectance and skin temperature were recorded for energy doses of 2, 6, 9, and 12 Joules using 635 nm (36 mW) and 808 nm (40 mW) wavelength laser diodes with irradiances within American National Standards Institute safety guidelines (4.88 mm diameter, 0.192 W/cm 2 and 4.88 mm diameter, 0.214 W/cm 2 , respectively). The key factors affecting reflectance to an important degree were skin color and wavelength. However, the skin color effects were different for the two wavelengths: reflectance decreased for darker skin with a greater decrease for red light than near infrared light. Transmittance was greater using 808 nm compared with 635 nm. However, the effect was partly lost when the skin was dark rather than light, and was increasingly lost as tissue thickness increased. Dose had an increasing effect on temperature (0.7-1.6°C across the 6, 9, and 12 J doses); any effects of wavelength, skin color, and tissue thickness were insignificant compared to dose effects. Subjects themselves were not aware of the increased skin temperature. Transmittance and reflectance changes as a function of energy were very small and likely of no clinical significance. Absorption did not change with higher energy doses and increasing temperature. Skin color and skin thickness affect transmittance and reflectance of laser light and must be accounted for when selecting energy dose to ensure therapeutic effectiveness at the target tissue. Skin heating appears not to be a concern when using 635 and 808 nm lasers at energy doses of up to 12 J and irradiance within American National Standards Institute standards. Photobiomodulation therapy should never exceed the American National Standards Institute

An improved model of heat-induced hyperalgesia--repetitive phasic heat pain causing primary hyperalgesia to heat and secondary hyperalgesia to pinprick and light touch.

Science.gov (United States)

Jürgens, Tim P; Sawatzki, Alexander; Henrich, Florian; Magerl, Walter; May, Arne

2014-01-01

This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (-31%) and in particular of secondary hyperalgesia (-59%) as well as the magnitude of hyperalgesia (-59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input.

An Improved Model of Heat-Induced Hyperalgesia—Repetitive Phasic Heat Pain Causing Primary Hyperalgesia to Heat and Secondary Hyperalgesia to Pinprick and Light Touch

Science.gov (United States)

Henrich, Florian; Magerl, Walter; May, Arne

2014-01-01

This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (−31%) and in particular of secondary hyperalgesia (−59%) as well as the magnitude of hyperalgesia (−59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input. PMID:24911787

Temperature field due to time-dependent heat sources in a large rectangular grid. Application for the KBS-3 repository

International Nuclear Information System (INIS)

Probert, T.; Claesson, Johan

1997-04-01

In the KBS-3 concept canisters containing nuclear waste are deposited along parallel tunnels over a large rectangular area deep below the ground surface. The temperature field in rock due to such a rectangular grid of heat-releasing canisters is studied. An analytical solution for this problem for any heat source has been presented in a preceding paper. The complete solution is summarized in this paper. The solution is by superposition divided into two main parts. There is a global temperature field due to the large rectangular canister area, while a local field accounts for the remaining heat source problem. In this sequel to the first report, the local solution is discussed in detail. The local solution consists of three parts corresponding to line heat sources along tunnels, point heat sources along a tunnel and a line heat source along a canister. Each part depends on two special variables only. These parts are illustrated in dimensionless form. Inside the repository the local temperature field is periodic in the horizontal directions and has a short extent in the vertical direction. This allows us to look at the solution in a parallelepiped around a canister. The solution in the parallelepiped is valid for all canisters that are not too close to the repository edges. The total temperature field is calculated for the KBS-3 case. The temperature field is calculated using a heat release that is valid for the first 10 000 years after deposition. The temperature field is shown in 23 figures in order to illustrate different aspects of the complex thermal process

Thermometry, calorimetry, and mean body temperature during heat stress.

Science.gov (United States)

Kenny, Glen P; Jay, Ollie

2013-10-01

Heat balance in humans is maintained at near constant levels through the adjustment of physiological mechanisms that attain a balance between the heat produced within the body and the heat lost to the environment. Heat balance is easily disturbed during changes in metabolic heat production due to physical activity and/or exposure to a warmer environment. Under such conditions, elevations of skin blood flow and sweating occur via a hypothalamic negative feedback loop to maintain an enhanced rate of dry and evaporative heat loss. Body heat storage and changes in core temperature are a direct result of a thermal imbalance between the rate of heat production and the rate of total heat dissipation to the surrounding environment. The derivation of the change in body heat content is of fundamental importance to the physiologist assessing the exposure of the human body to environmental conditions that result in thermal imbalance. It is generally accepted that the concurrent measurement of the total heat generated by the body and the total heat dissipated to the ambient environment is the most accurate means whereby the change in body heat content can be attained. However, in the absence of calorimetric methods, thermometry is often used to estimate the change in body heat content. This review examines heat exchange during challenges to heat balance associated with progressive elevations in environmental heat load and metabolic rate during exercise. Further, we evaluate the physiological responses associated with heat stress and discuss the thermal and nonthermal influences on the body's ability to dissipate heat from a heat balance perspective.

Comparative investigation of five nanoparticles in flow of viscous fluid with Joule heating and slip due to rotating disk

Science.gov (United States)

Qayyum, Sumaira; Khan, Muhammad Ijaz; Hayat, Tasawar; Alsaedi, Ahmed

2018-04-01

Present article addresses the comparative study for flow of five water based nanofluids. Flow in presence of Joule heating is generated by rotating disk with variable thickness. Nanofluids are suspension of Silver (Ag), Copper (Cu), Copper oxide (CuO), Aluminum oxide or Alumina (Al2O3), Titanium oxide or titania (TiO2) and water. Boundary layer approximation is applied to partial differential equations. Using Von Karman transformations the partial differential equations are converted to ordinary differential equations. Convergent series solutions are obtained. Graphical results are presented to examine the behaviors of axial, radial and tangential velocities, temperature, skin friction and Nusselt number. It is observed that radial, axial and tangential velocities decay for slip parameters. Axial velocity decays for larger nanoparticle volume fraction. Effect of nanofluids on velocities dominant than base material. Temperature rises for larger Eckert number and temperature of silver water nanofluid is more because of its higher thermal conductivity. Surface drag force reduces for higher slip parameters. Transfer of heat is more for larger disk thickness index.

Methodological assessment of skin and limb blood flows in the human forearm during thermal and baroreceptor provocations

OpenAIRE

Brothers, R. Matthew; Wingo, Jonathan E.; Hubing, Kimberly A.; Crandall, Craig G.

2010-01-01

Skin blood flow responses in the human forearm, assessed by three commonly used technologies—single-point laser-Doppler flowmetry, integrated laser-Doppler flowmetry, and laser-Doppler imaging—were compared in eight subjects during normothermic baseline, acute skin-surface cooling, and whole body heat stress (Δ internal temperature = 1.0 ± 0.2°C; P < 0.001). In addition, while normothermic and heat stressed, subjects were exposed to 30-mmHg lower-body negative pressure (LBNP). Skin blood flow...

Third degree skin burns caused by a MRI conditional electrocardiographic monitoring system

Directory of Open Access Journals (Sweden)

Brix L

2016-10-01

Full Text Available Two unusual cases of third degree skin burns are reported using MRI approved electrocardiographic leads. This is very uncommon as it is most often the electrodes which are the source of heat related issues. Both patients were sedated due to pain related issues of their lower spine. The burns were caused by a combination of using a 3 Tesla MRI scanner and the inability to cry out during scanning. We would like to bring forward a message that even when using MRI conditional equipment, clinical staff must be extremely careful in order to secure safe image acquisition using MRI.

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.

Parametric investigation of heating due to magnetic fluid hyperthermia in a tumor with blood perfusion

Energy Technology Data Exchange (ETDEWEB)

Liangruksa, Monrudee [Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Ganguly, Ranjan [Department of Power Engineering, Jadavpur University, Kolkata 700098 (India); Puri, Ishwar K., E-mail: ikpuri@vt.ed [Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States)

2011-03-15

Magnetic fluid hyperthermia (MFH) is a cancer treatment that can selectively elevate the tumor temperature without significantly damaging the surrounding healthy tissue. Optimal MFH design requires a fundamental parametric investigation of the heating of soft materials by magnetic fluids. We model the problem of a spherical tumor and its surrounding healthy tissue that are heated by exciting a homogeneous dispersion of magnetic nanoparticles infused only into the tumor with an external AC magnetic field. The key dimensionless parameters influencing thermotherapy are the Peclet, Fourier, and Joule numbers. Analytical solutions for transient and steady hyperthermia provide correlations between these parameters and the portions of tumor and healthy tissue that are subjected to a threshold temperature beyond which they are damaged. Increasing the ratio of the Fourier and Joule numbers also increases the tumor temperature, but doing so can damage the healthy tissue. Higher magnetic heating is required for larger Peclet numbers due to the larger convection heat loss that occurs through blood perfusion. A comparison of the model predictions with previous experimental data for MFH applied to rabbit tumors shows good agreement. The optimal MFH conditions are identified based on two indices, the fraction I{sub T} of the tumor volume in which the local temperature is above a threshold temperature and the ratio I{sub N} of the damaged normal tissue volume to the tumor tissue volume that also lies above it. The spatial variation in the nanoparticle concentration is also considered. A Gaussian distribution provides efficacy while minimizing the possibility of generating a tumor hot spot. Varying the thermal properties of tumor and normal tissue alters I{sub T}and I{sub N} but the nature of the temperature distribution remains unchanged. - Research highlights: > Analytical model of magnetic fluid hyperthermia of tumor tissue perfused with magnetic nanoparticles that is surrounded

Parametric investigation of heating due to magnetic fluid hyperthermia in a tumor with blood perfusion

International Nuclear Information System (INIS)

Liangruksa, Monrudee; Ganguly, Ranjan; Puri, Ishwar K.

2011-01-01

Magnetic fluid hyperthermia (MFH) is a cancer treatment that can selectively elevate the tumor temperature without significantly damaging the surrounding healthy tissue. Optimal MFH design requires a fundamental parametric investigation of the heating of soft materials by magnetic fluids. We model the problem of a spherical tumor and its surrounding healthy tissue that are heated by exciting a homogeneous dispersion of magnetic nanoparticles infused only into the tumor with an external AC magnetic field. The key dimensionless parameters influencing thermotherapy are the Peclet, Fourier, and Joule numbers. Analytical solutions for transient and steady hyperthermia provide correlations between these parameters and the portions of tumor and healthy tissue that are subjected to a threshold temperature beyond which they are damaged. Increasing the ratio of the Fourier and Joule numbers also increases the tumor temperature, but doing so can damage the healthy tissue. Higher magnetic heating is required for larger Peclet numbers due to the larger convection heat loss that occurs through blood perfusion. A comparison of the model predictions with previous experimental data for MFH applied to rabbit tumors shows good agreement. The optimal MFH conditions are identified based on two indices, the fraction I T of the tumor volume in which the local temperature is above a threshold temperature and the ratio I N of the damaged normal tissue volume to the tumor tissue volume that also lies above it. The spatial variation in the nanoparticle concentration is also considered. A Gaussian distribution provides efficacy while minimizing the possibility of generating a tumor hot spot. Varying the thermal properties of tumor and normal tissue alters I T and I N but the nature of the temperature distribution remains unchanged. - Research Highlights: →Analytical model of magnetic fluid hyperthermia of tumor tissue perfused with magnetic nanoparticles that is surrounded by healthy tissue

Internal (Annular) and Compressible External (Flat Plate) Turbulent Flow Heat Transfer Correlations.

Energy Technology Data Exchange (ETDEWEB)

Dechant, Lawrence [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, Justin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-01-01

Here we provide a discussion regarding the applicability of a family of traditional heat transfer correlation based models for several (unit level) heat transfer problems associated with flight heat transfer estimates and internal flow heat transfer associated with an experimental simulation design (Dobranich 2014). Variability between semi-empirical free-flight models suggests relative differences for heat transfer coefficients on the order of 10%, while the internal annular flow behavior is larger with differences on the order of 20%. We emphasize that these expressions are strictly valid only for the geometries they have been derived for e.g. the fully developed annular flow or simple external flow problems. Though, the application of flat plate skin friction estimate to cylindrical bodies is a traditional procedure to estimate skin friction and heat transfer, an over-prediction bias is often observed using these approximations for missile type bodies. As a correction for this over-estimate trend, we discuss a simple scaling reduction factor for flat plate turbulent skin friction and heat transfer solutions (correlations) applied to blunt bodies of revolution at zero angle of attack. The method estimates the ratio between axisymmetric and 2-d stagnation point heat transfer skin friction and Stanton number solution expressions for sub-turbulent Reynolds numbers %3C1x10 4 . This factor is assumed to also directly influence the flat plate results applied to the cylindrical portion of the flow and the flat plate correlations are modified by

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.

Laser heat hyperalgesia is not a feature of non-specific chronic low back pain.

Science.gov (United States)

Franz, M; Ritter, A; Puta, C; Nötzel, D; Miltner, W H R; Weiss, T

2014-11-01

Based upon studies using mechanical pin-prick, pressure, electrical or heat stimuli applied to painful and/or pain-free parts of the body, chronic low back pain (CLBP) has been shown to be associated with generalized and enhanced pain sensitivity and altered brain responses to noxious stimuli. To date, no study examined the processing of noxious laser heat pulses, which are known to selectively excite thermal nociceptors located in the superficial skin layers, in CLBP. We studied laser heat pain thresholds (LHPTs) and nociceptive laser-evoked brain electrical potentials (LEPs) following skin stimulation of the pain-affected back and the pain-free abdomen using noxious laser heat stimulation in 16 CLBP patients and 16 age- and gender-matched healthy controls (HCs). We observed no statistically significant differences in LHPTs between CLBP patients and HCs, neither on the back nor on the abdomen. Furthermore, we found no evidence for altered brain responses between CLBP patients and HCs in response to stimulation of the back and abdomen in single-trial latencies and amplitudes of LEP components (N2, P2). The results are in contrast to previous studies showing hypersensitivity to different experimental noxious stimuli (e.g., contact heat). We argue that these discrepancies may be due to low spatial and temporal summation within the central nervous system following laser heat stimulation. Our results indicate important methodological differences between laser heat and thermode stimulation that should be taken into account when interpreting results, such as from thermal quantitative sensory testing. © 2014 European Pain Federation - EFIC®

Skin denervation does not alter cortical potentials to surface concentric electrode stimulation: A comparison with laser evoked potentials and contact heat evoked potentials.

Science.gov (United States)

La Cesa, S; Di Stefano, G; Leone, C; Pepe, A; Galosi, E; Alu, F; Fasolino, A; Cruccu, G; Valeriani, M; Truini, A

2018-01-01

In the neurophysiological assessment of patients with neuropathic pain, laser evoked potentials (LEPs), contact heat evoked potentials (CHEPs) and the evoked potentials by the intraepidermal electrical stimulation via concentric needle electrode are widely agreed as nociceptive specific responses; conversely, the nociceptive specificity of evoked potentials by surface concentric electrode (SE-PREPs) is still debated. In this neurophysiological study we aimed at verifying the nociceptive specificity of SE-PREPs. We recorded LEPs, CHEPs and SE-PREPs in eleven healthy participants, before and after epidermal denervation produced by prolonged capsaicin application. We also used skin biopsy to verify the capsaicin-induced nociceptive nerve fibre loss in the epidermis. We found that whereas LEPs and CHEPs were suppressed after capsaicin-induced epidermal denervation, the surface concentric electrode stimulation of the same denervated skin area yielded unchanged SE-PREPs. The suppression of LEPs and CHEPs after nociceptive nerve fibre loss in the epidermis indicates that these techniques are selectively mediated by nociceptive system. Conversely, the lack of SE-PREP changes suggests that SE-PREPs do not provide selective information on nociceptive system function. Capsaicin-induced epidermal denervation abolishes laser evoked potentials (LEPs) and contact heat evoked potentials (CHEPs), but leaves unaffected pain-related evoked potentials by surface concentric electrode (SE-PREPs). These findings suggest that unlike LEPs and CHEPs, SE-PREPs are not selectively mediated by nociceptive system. © 2017 European Pain Federation - EFIC®.

Higher Atmosphere Heating due to black carbon Over the Northern Part of India

Science.gov (United States)

Tiwari, S.; Singh, S., , Dr

2017-12-01

Light-absorbing, atmospheric particles have gained greater attention in recent years because of their direct and indirect impacts on regional and global climate. Atmospheric black carbon (BC) aerosol (also called soot particle) is a leading climate warming agent, yet uncertainties in the global direct aerosol radiative forcing remain large. Based on a year of aerosol absorption measurements at seven wavelengths, BC concentrations were investigated in Dhanbad, the coal capital of India. Coal is routinely burned for cooking and residential heat as well as in small industries. The mean daily concentrations of ultraviolet-absorbing black carbon measured at 370 nm (UVBC) and black carbon measured at 880 nm (BC) were 9.8 ± 5.7 and 6.5 ± 3.8 μg m-3, respectively. The difference between UVBC and BC, Delta-C, is an indicator of biomass or residential coal burning and averaged 3.29 ± 4.61 μg m-3. An alternative approach uses the calculation of the Angstrom Exponent (AE) to estimate the amounts of biomass/coal and traffic BC. Biomass/coal burning contributed 87% and fossil fuel combustion contributed 13% to the annual average BC concentration. In the post-monsoon season, potential source contribution function analysis showed that air masses came from the central and northwestern Indo-Gangetic Plains resulting in mean UVBC values of 10.9 μg m-3 and BC of 7.2 μg m-3. The mean winter UVBC and BC concentrations were 15.0 and 10.1 μg m-3, respectively. These highest values were largely driven by local sources under conditions of poor dispersion. The direct radiative forcing (DRF) due to UVBC and BC at the surface (SFC) and the top of the atmosphere (TOA) were calculated. The mean atmospheric heating rates due to UVBC and BC were estimated to be 1.40°K day-1 and 1.18°K day-1, respectively. This high heating rate may affect the monsoon circulation in this region.

Potential skin involvement in ALS: revisiting Charcot's observation - a review of skin abnormalities in ALS.

Science.gov (United States)

Paré, Bastien; Gros-Louis, François

2017-07-26

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients' skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel in vitro ALS tissue-engineered skin model, derived from patients, for the study of ALS.

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.

Effect of heat transfer on unsteady MHD flow of blood in a permeable vessel in the presence of non-uniform heat source

Directory of Open Access Journals (Sweden)

A. Sinha

2016-09-01

Full Text Available This paper presents a theoretical analysis of blood flow and heat transfer in a permeable vessel in the presence of an external magnetic field. The unsteadiness in the coupled flow and temperature fields is considered to be caused due to the time-dependent stretching velocity and the surface temperature of the vessel. The non-uniform heat source/sink effect on blood flow and heat transfer is taken into account. This study is of potential value in the clinical treatment of cardiovascular disorders accompanied by accelerated circulation. The problem is treated mathematically by reducing it to a system of coupled nonlinear differential equations, which have been solved by using similarity transformation and boundary layer approximation. The resulting nonlinear coupled ordinary differential equations are solved numerically by using an implicit finite difference scheme. Computational results are obtained for the velocity, temperature, the skin-friction coefficient and the rate of heat transfer in the vessel. The estimated results are compared with another analytical study reported earlier in scientific literatures. The present study reveals that the heat transfer rate is enhanced as the value of the unsteadiness parameter increases, but it reduces as the space-dependence parameter for heat source/sink increases.

Modeling and simulation of heat distribution in human skin caused by laser irradiation

NARCIS (Netherlands)

Luan, Y.; Dams, S.D.

2009-01-01

Study of light-based skin rejuvenation needs prospective insights of mechanism of laser tissue interaction. A well-built model plays a key role in predicting temperature distribution in human skin exposed to laser irradiation. Therefore, it not only provides guidance for in vitro experiment, but

MHD Convective Flow of Jeffrey Fluid Due to a Curved Stretching Surface with Homogeneous-Heterogeneous Reactions.

Directory of Open Access Journals (Sweden)

Maria Imtiaz

Full Text Available This paper looks at the flow of Jeffrey fluid due to a curved stretching sheet. Effect of homogeneous-heterogeneous reactions is considered. An electrically conducting fluid in the presence of applied magnetic field is considered. Convective boundary conditions model the heat transfer analysis. Transformation method reduces the governing nonlinear partial differential equations into the ordinary differential equations. Convergence of the obtained series solutions is explicitly discussed. Characteristics of sundry parameters on the velocity, temperature and concentration profiles are analyzed by plotting graphs. Computations for pressure, skin friction coefficient and surface heat transfer rate are presented and examined. It is noted that fluid velocity and temperature through curvature parameter are enhanced. Increasing values of Biot number correspond to the enhancement in temperature and Nusselt number.

Method of making self-cleaning skin-like prosthetic polymer surfaces

Science.gov (United States)

Simpson, John T.; Ivanov, Ilia N.; Shibata, Jason

2017-06-06

An external covering and method of making an external covering for hiding the internal endoskeleton of a mechanical (e.g., prosthetic) device that exhibits skin-like qualities is provided. The external covering generally comprises an internal bulk layer in contact with the endoskeleton of the prosthetic device and an external skin layer disposed about the internal bulk layer. The external skin layer is comprised of a polymer composite with carbon nanotubes embedded therein. The outer surface of the skin layer has multiple cone-shaped projections that provide the external skin layer with superhydrophobicity. The carbon nanotubes are preferably vertically aligned between the inner surface and outer surface of the external skin layer in order to provide the skin layer with the ability to transmit heat. Superhydrophobic powders may optionally be used as part of the polymer composite or applied as a coating to the surface of the skin layer to enhance superhydrophobicity.

New bioprinted skin, cosmetic in vitro model.

Science.gov (United States)

Cadau, Sebastien; Rival, Delphine; Andre-Frei, Valerie; Chavan M, Manasi; Fayol, Delphine; Salducci, Marine; Brisson, Bruno; Guillemot, Fabien

We developed a new evolution of three-dimensional skin equivalent due to the optimization of four-dimensional laser-assisted bioprinting and skin equivalent culture protocols. This allowed us to produce fully bioprinted skin equivalents that are closed to current skin equivalents and suitable to test cosmetic ingredients. Particularly, we performed preliminary evaluation of maturogens to improve the dermis maturation before the epidermal seeding and we designed a specific "micropattern" to reproduce the nonlinear aspect of the dermal-epidermal junction. Finally an active ingredient was applied during the production of the bioprinted skin equivalent.

Thermal stress analysis of space shuttle orbiter wing skin panel and thermal protection system

Science.gov (United States)

Ko, William L.; Jenkins, Jerald M.

1987-01-01

Preflight thermal stress analysis of the space shuttle orbiter wing skin panel and the thermal protection system (TPS) was performed. The heated skin panel analyzed was rectangular in shape and contained a small square cool region at its center. The wing skin immediately outside the cool region was found to be close to the state of elastic instability in the chordwise direction based on the conservative temperature distribution. The wing skin was found to be quite stable in the spanwise direction. The potential wing skin thermal instability was not severe enough to tear apart the strain isolation pad (SIP) layer. Also, the preflight thermal stress analysis was performed on the TPS tile under the most severe temperature gradient during the simulated reentry heating. The tensile thermal stress induced in the TPS tile was found to be much lower than the tensile strength of the TPS material. The thermal bending of the TPS tile was not severe enough to cause tearing of the SIP layer.

Ethyl cellulose nanocarriers and nanocrystals differentially deliver dexamethasone into intact, tape-stripped or sodium lauryl sulfate-exposed ex vivo human skin - assessment by intradermal microdialysis and extraction from the different skin layers.

Science.gov (United States)

Döge, Nadine; Hönzke, Stefan; Schumacher, Fabian; Balzus, Benjamin; Colombo, Miriam; Hadam, Sabrina; Rancan, Fiorenza; Blume-Peytavi, Ulrike; Schäfer-Korting, Monika; Schindler, Anke; Rühl, Eckart; Skov, Per Stahl; Church, Martin K; Hedtrich, Sarah; Kleuser, Burkhard; Bodmeier, Roland; Vogt, Annika

2016-11-28

Understanding penetration not only in intact, but also in lesional skin with impaired skin barrier function is important, in order to explore the surplus value of nanoparticle-based drug delivery for anti-inflammatory dermatotherapy. Herein, short-term ex vivo cultures of (i) intact human skin, (ii) skin pretreated with tape-strippings and (iii) skin pre-exposed to sodium lauryl sulfate (SLS) were used to assess the penetration of dexamethasone (Dex). Intradermal microdialysis was utilized for up to 24h after drug application as commercial cream, nanocrystals or ethyl cellulose nanocarriers applied at the therapeutic concentration of 0.05%, respectively. In addition, Dex was assessed in culture media and extracts from stratum corneum, epidermis and dermis after 24h, and the results were compared to those in heat-separated split skin from studies in Franz diffusion cells. Providing fast drug release, nanocrystals significantly accelerated the penetration of Dex. In contrast to the application of cream and ethyl cellulose nanocarriers, Dex was already detectable in eluates after 6h when applying nanocrystals on intact skin. Disruption of the skin barrier further accelerated and enhanced the penetration. Encapsulation in ethyl cellulose nanocarriers delayed Dex penetration. Interestingly, for all formulations highly increased concentrations in the dialysate were observed in tape-stripped skin, whereas the extent of enhancement was less in SLS-exposed skin. The results were confirmed in tissue extracts and were in line with the predictions made by in vitro release studies and ex vivo Franz diffusion cell experiments. The use of 45kDa probes further enabled the collection of inflammatory cytokines. However, the estimation of glucocorticoid efficacy by Interleukin (IL)-6 and IL-8 analysis was limited due to the trauma induced by the probe insertion. Ex vivo intradermal microdialysis combined with culture media analysis provides an effective, skin-sparing method for

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 ...

Investigation on Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can...... solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out....

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.

Electrophysiological and psychophysical correlates of spatial summation to noxious heat: the possible role of A-delta fibers.

Science.gov (United States)

Granovsky, Y; Raz, N; Defrin, R

2017-02-01

Although spatial summation of pain (SSP) is central to the processing of pain intensity and quality, its mechanism is not fully understood. We previously found greater heat SSP in hairy than in glabrous skin, suggesting that perhaps A-mechano-heat II (AMH-II) nociceptors are the dominant subserving system. In order to further explore the role of A-delta fibers in heat-induced SSP, we analyzed the electrophysiological correlates of SSP under conditions that minimize the influence of skin thicknesses. Among 17 subjects, fast rate of rise (70 °C/sec) heat stimuli that induced a pre-fixed, similar, SSP magnitude for hairy and glabrous skin were repeatedly administered using large and small probes, during which time the contact heat-evoked potentials (CHEPs) and pain ratings were recorded. Both N2 and P2 amplitudes were larger in hairy than in glabrous skin, but a differential effect of SSP was found on the CHEPs. Despite similar psychophysical SSP in hairy and glabrous skin, the electrophysiological SSP reflected in N2 but not P2 amplitude was larger in hairy skin. Nevertheless, regardless of skin type, SSP was manifested by an increase in P2 amplitudes. Considering the uniform psychophysical SSP for the two skin types, the fast stimulation rate and lower activity of AMH-II in glabrous skin, a greater electrophysiological SSP in hairy than in glabrous skin may suggest that SSP is mainly subserved by AMH nociceptors. The overall SSP effect, manifested in greater P2 amplitude, may reflect specific brain responses aimed to prepare the individual to an increased potential tissue damage.

Use of the novel contact heat evoked potential stimulator (CHEPS for the assessment of small fibre neuropathy: correlations with skin flare responses and intra-epidermal nerve fibre counts

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Chizh Boris A

2007-08-01

Full Text Available Abstract Background The Contact Heat Evoked Potential Stimulator (CHEPS rapidly stimulates cutaneous small nerve fibres, and resulting evoked potentials can be recorded from the scalp. We have studied patients with symptoms of sensory neuropathy and controls using CHEPS, and validated the findings using other objective measures of small nerve fibres i.e. the histamine-induced skin flare response and intra-epidermal fibres (IEF, and also quantitative sensory testing (QST, a subjective measure. Methods In patients with symptoms of sensory neuropathy (n = 41 and healthy controls (n = 9 we performed clinical examination, QST (monofilament, vibration and thermal perception thresholds, nerve conduction studies, histamine-induced skin flares and CHEPS. Skin punch biopsies were immunostained using standard ABC immunoperoxidase for the nerve marker PGP 9.5 or the heat and capsaicin receptor TRPV1. Immunoreactive IEF were counted per length of tissue section and epidermal thickness recorded. Results Amplitudes of Aδ evoked potentials (μV following face, arm or leg stimulation were reduced in patients (e.g. for the leg: mean ± SEM – controls 11.7 ± 1.95, patients 3.63 ± 0.85, p = 0.0032. Patients showed reduced leg skin flare responses, which correlated with Aδ amplitudes (rs = 0.40, p = 0.010. In patient leg skin biopsies, PGP 9.5- and TRPV1-immunoreactive IEF were reduced and correlated with Aδ amplitudes (PGP 9.5, rs = 0.51, p = 0.0006; TRPV1, rs = 0.48, p = 0.0012. Conclusion CHEPS appears a sensitive measure, with abnormalities observed in some symptomatic patients who did not have significant IEF loss and/or QST abnormalities. Some of the latter patients may have early small fibre dysfunction or ion channelopathy. CHEPS provides a clinically practical, non-invasive and objective measure, and can be a useful additional tool for the assessment of sensory small fibre neuropathy. Although further evaluation is required, the technique shows

Skin-friction measurements in high-enthalpy hypersonic boundary layers

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

2003-06-01

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

Cows exposed to heat stress during fetal life exhibit improved thermal tolerance.

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Ahmed, B M S; Younas, U; Asar, T O; Dikmen, S; Hansen, P J; Dahl, G E

2017-08-01

Maternal heat stress during late gestation affects calf function during postnatal life. The objective of the present study was to evaluate whether calves that experience heat stress in utero have altered thermoregulatory responses to acute heat stress later in life. Specifically, the hypothesis was that heat stress in utero would improve the response to acute heat stress at maturity. Females were born to dams exposed to heat stress or cooled during late gestation preceding their birth. All animals were raised postnatally under identical management. Twelve lactating Holstein cows that were exposed to in utero heat stress (HT) and 12 that were exposed to in utero control (CON) were used. A heat stress challenge was conducted in 3 blocks using 4 HT and 4 CON cows matched according to milk yield, stage of lactation, and parity. Each challenge consisted of transfer from a barn with shade and evaporative cooling to one with shade but no additional cooling for 48 h. The challenge was replicated twice for each block. Sweating rate, respiration rate, rectal temperature (RT), and skin temperature were measured on each cow at 0900, 1100, 1300, 1500, and 1700 h for 2 consecutive days. Mean ambient temperature across 6 challenge days was 26.15 ± 4.75°C. Tendencies for differences at 1700 h were observed between treatments for RT (HT: 39.5 ± 0.1; CON: 39.6 ± 0.1°C; = 0.065), however, there was no difference in respiration rate (HT: 77.6 ± 1.6; CON: 79.5 ± 1.6 bpm; = 0.85). Sweating rate for shaved skin (HT: 29.4 ± 2.0; CON: 36.0 ± 2.0 g/mh; = 0.057) and for non-shaved skin (HT: 22.5 ± 1.5; CON: 29.2 ± 1.2 g/mh; = 0.01) differed between groups. However, there was no effect on skin temperature at the shaved location (HT: 36.2 ± 0.2; CON: 36.0 ± 0.2°C; = 0.81), but there was a tendency for differences for the non-shaved area (HT: 35.4 ± 0.2; CON: 34.9 ± 0.2°C; = 0.097). Cows that underwent in utero heat stress had greater skin temperature at 1700 h vs. in utero

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

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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.

Immunologic changes in children with egg allergy ingesting extensively heated egg.

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Lemon-Mulé, Heather; Sampson, Hugh A; Sicherer, Scott H; Shreffler, Wayne G; Noone, Sally; Nowak-Wegrzyn, Anna

2008-11-01

Prior studies have suggested that heated egg might be tolerated by some children with egg allergy. We sought to confirm tolerance of heated egg in a subset of children with egg allergy, to evaluate clinical and immunologic predictors of heated egg tolerance, to characterize immunologic changes associated with continued ingestion of heated egg, and to determine whether a diet incorporating heated egg is well tolerated. Subjects with documented IgE-mediated egg allergy underwent physician-supervised oral food challenges to extensively heated egg (in the form of a muffin and a waffle), with tolerant subjects also undergoing regular egg challenges (in a form of scrambled egg or French toast). Heated egg-tolerant subjects incorporated heated egg into their diets. Skin prick test wheal diameters and egg white, ovalbumin, and ovomucoid IgE levels, as well as ovalbumin and ovomucoid IgG4 levels, were measured at baseline for all subjects and at 3, 6, and 12 months for those tolerant of heated egg. Sixty-four of 117 subjects tolerated heated egg, 23 tolerated regular egg, and 27 reacted to heated egg. Heated egg-reactive subjects had larger skin test wheals and greater egg white-specific, ovalbumin-specific, and ovomucoid-specific IgE levels compared with heated egg- and egg-tolerant subjects. Continued ingestion of heated egg was associated with decreased skin test wheal diameters and ovalbumin-specific IgE levels and increased ovalbumin-specific and ovomucoid-specific IgG4 levels. The majority of subjects with egg allergy were tolerant of heated egg. Continued ingestion of heated egg was well tolerated and associated with immunologic changes that paralleled the changes observed with the development of clinical tolerance to regular egg.

Microfocused ultrasound for skin tightening.

Science.gov (United States)

MacGregor, Jennifer L; Tanzi, Elizabeth L

2013-03-01

The demand for noninvasive skin tightening procedures is increasing as patients seek safe and effective alternatives to aesthetic surgical procedures of the face, neck, and body. Over the past decade, radiofrequency and infrared laser devices have been popularized owing to their ability to deliver controlled heat to the dermis, stimulate neocollagenesis, and effect modest tissue tightening with minimal recovery. However, these less invasive approaches are historically associated with inferior efficacy so that surgery still remains the treatment of choice to address moderate to severe tissue laxity. Microfocused ultrasound was recently introduced as a novel energy modality for transcutaneous heat delivery that reaches the deeper subdermal connective tissue in tightly focused zones at consistent programmed depths. The goal is to produce a deeper wound healing response at multiple levels with robust collagen remodeling and a more durable clinical response. The Ulthera device (Ulthera, Inc, Meza, AZ), with refined microfocused ultrasound technology, has been adapted specifically for skin tightening and lifting with little recovery or risk of complications since its introduction in 2009. As clinical parameters are studied and optimized, enhanced efficacy and consistency of clinical improvement is expected.

An oral TRPV1 antagonist attenuates laser radiant-heat-evoked potentials and pain ratings from UV(B)-inflamed and normal skin.

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Schaffler, Klaus; Reeh, Peter; Duan, W Rachel; Best, Andrea E; Othman, Ahmed A; Faltynek, Connie R; Locke, Charles; Nothaft, Wolfram

2013-02-01

Laser (radiant-heat) evoked potentials (LEPs) from vertex-EEG peak-to-peak (PtP) amplitude were used to determine acute antinociceptive/antihyperalgesic efficacy of ABT-102, a novel TRPV1 antagonist efficacious in preclinical pain models, compared with active controls and placebo in normal and UV(B)-inflamed skin. This was a randomized, placebo- and active-controlled, double-blind, intra-individual, crossover trial. Twenty-four healthy subjects received six sequences of single doses of ABT-102 (0.5, 2, 6 mg), etoricoxib 90 mg, tramadol 100 mg and placebo. Painful stimuli were induced by CO(2) -laser on normal and UV(B) -inflamed skin. LEPs and visual analogue scale (VAS-pain) ratings were taken at baseline and hourly up to 8 h post-dose from both skin types. Compared with placebo, significant mean decreases in the primary variable of LEP PtP-amplitude from UV(B)-inflamed skin were observed with ABT-102 6 mg (P < 0.001), ABT-102 2 mg (P = 0.002), tramadol 100 mg (P < 0.001), and etoricoxib 90 mg (P = 0.001) over the 8 h period; ABT-102 0.5 mg was similar to placebo. ABT-102 6 mg was superior to active controls over the 8 h period (P < 0.05) whereas ABT-102 2 mg was comparable. Improvements in VAS scores compared with placebo were observed with ABT-102 6 mg (P < 0.001) and ABT-102 2 mg (P = 0.002). ABT-102 average plasma concentrations were 1.3, 4.4 and 9.4 ng ml(-1) for the 0.5, 2 and 6 mg doses, respectively. There were no clinically significant safety findings. TRPV-1 antagonism appears promising in the management of clinical pain, but requires further investigation. © 2012 Abbott. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

Human reconstructed skin xenografts on mice to model skin physiology.

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Salgado, Giorgiana; Ng, Yi Zhen; Koh, Li Fang; Goh, Christabelle S M; Common, John E

Xenograft models to study skin physiology have been popular for scientific use since the 1970s, with various developments and improvements to the techniques over the decades. Xenograft models are particularly useful and sought after due to the lack of clinically relevant animal models in predicting drug effectiveness in humans. Such predictions could in turn boost the process of drug discovery, since novel drug compounds have an estimated 8% chance of FDA approval despite years of rigorous preclinical testing and evaluation, albeit mostly in non-human models. In the case of skin research, the mouse persists as the most popular animal model of choice, despite its well-known anatomical differences with human skin. Differences in skin biology are especially evident when trying to dissect more complex skin conditions, such as psoriasis and eczema, where interactions between the immune system, epidermis and the environment likely occur. While the use of animal models are still considered the gold standard for systemic toxicity studies under controlled environments, there are now alternative models that have been approved for certain applications. To overcome the biological limitations of the mouse model, research efforts have also focused on "humanizing" the mice model to better recapitulate human skin physiology. In this review, we outline the different approaches undertaken thus far to study skin biology using human tissue xenografts in mice and the technical challenges involved. We also describe more recent developments to generate humanized multi-tissue compartment mice that carry both a functioning human immune system and skin xenografts. Such composite animal models provide promising opportunities to study drugs, disease and differentiation with greater clinical relevance. Copyright © 2017 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Changes occurring in vegetable oils composition due to microwave heating

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Hassan El-Mallah, M.

2003-12-01

Full Text Available The effect of microwave heating on three vegetable oils having different lipid compositions was studied. Sunflower, soybean and peanut oils in comparison with oil admixture of soybean and peanut oil (1:1, w/w, were selected for this study. Each oil was heated for 2, 4, 6, 8, 10, 12, 15 and 18 minutes in microwave oven. Peroxide value, free acidity and colour absorbance (at 420 nm were proportionally increasing with the increase of heating period. Colour absorption threw light on the formation of browning products arising from phospholipids during microwave heating. Total tocopherol contents were determined by preparative thin layer chromatography, whereas the fatty acid compositions and formed epoxy acid were analyzed by capillary gas liquid chromatography. The formed conjugated dienes and trienes were determined by UV spectrophotometry. It was found that the total tocopherols of the microwave heated oils, decreased depending on the type of the predominating tocopherols. Also a relation of peroxide formation, during microwave heating, with changes in total tocopherol composition was discussed. It was found that polyunsaturated fatty acids generally decreased by increasing the heating period. The results obtained from the heated oil admixture helped interpret the results obtained from other heated individual oils.Se estudia el efecto del calentamiento en horno de microondas sobre aceites de diferente composición en ácidos grasos. Aceites de girasol, soja, cacahuete y una mezcla de soja y cacahuete al 50%, se calentaron durante 2, 4, 6, 8 10, 12, 15 y 18 minutos. Los valores de índice de peróxidos, acidez libre y absorbancia a 420 nm fueron proporcionales al tiempo de calentamiento. Otras determinaciones incluyeron el contenido total en tocoferoles mediante cromatografía en capa fina, la composición en ácidos grasos y en epoxiácidos mediante cromatografía gas líquido, y la formación de dienos y trienos conjugados mediante

Heat transfer improvement due to the imposition of non-uniform wall heating for in-tube laminar forced convection

International Nuclear Information System (INIS)

Hajmohammadi, M.R.; Poozesh, S.; Rahmani, M.; Campo, A.

2013-01-01

This paper explores the bearing that a non-uniform distribution of heat flux used as a wall boundary condition exerts on the heat transfer improvement in a round pipe. Because the overall heat load is considered fixed, the heat transfer improvement is viewed through a reduction in the maximum temperature (‘hot spot’) by imposing optimal distribution of heat flux. Two cases are studied in detail 1) fully developed and 2) developing flow. Peak temperatures in the heated pipe wall are calculated via an analytical approach for the fully developed case, while a numerical simulation based on CFD is employed for the developing case. By relaxing the heat flux distribution on the pipe wall, the numerical results imply that the optimum distribution of heat flux, which minimizes the peak temperatures corresponds with the ‘descending’ distribution. Given that the foregoing approach is quite different from the ‘ascending’ heat flux distribution recommended in the literature by means of the entropy generation minimization (EGM) method, it is inferred that the optimization of heat transfer and fluid flow, in comparison with the thermodynamic optimization, may bring forth quite different guidelines for the designs of thermal systems under the same constraints and circumstances. -- Highlights: • Considered the bearing of non-uniform distribution of heat flux on the hot spots. • Determined the optimal distribution of heat flux that minimizes the hot spots. • Results are compared with those obtained by EGM method

Touraine Solente Gole syndrome: The elephant skin disease

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T. M. Sheeja Rajan

2013-01-01

Full Text Available Touraine Solente Gole syndrome is a rare hereditary syndrome of primary pachydermoperiostosis, with the characteristic triad of pachydermia (or elephant like skin, periostosis and acropachia. A 27-year-old patient presented with aesthetic deformity of forehead due to deep skin folds and coarsening of facial features due to progressive thickening of skin. Associated palmoplantar hyperkeratosis with broadened of finger and toe tips and digital clubbing were noticed. Dermatologic evaluation revealed cutis verticis gyrata of scalp, seborrhoeic hyperplasia of face and hyperhidrosis. Natural history of the disease and aetiopathogenesis were reviewed. Aesthetic correction of forehead through frontal rhytidectomy was attempted.

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

Skin Manifestations of Endocrine Diseases.

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Demirkesen, Cuyan

2015-01-01

Endocrine diseases may result in changes in cutaneous function and morphology, which cause various skin manifestations, including nonspecific or pathognomonic signs. Some of these manifestations are already known dermatologic diseases with only increased frequency in this patient group. As a result the skin may the play role of a screen displaying endocrine disorders, either due to hormone excess or deficiency. Awareness of the skin manifestations may permit prompt and adequate approach to the patients, and therefore facilitate the early diagnosis of the endocrine disease and even be life saving. Some of these manifestations may be recognized clinically, but sometimes they need to be confirmed histopathologically. In this article, many endocrine diseases and their associated skin lesions will be reviewed briefly.

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.

In vitro methods for evaluating skin hydration under diapers and incontinence products.

Science.gov (United States)

Tate, M L; Wright, A S

2017-11-01

Excessive skin hydration from wearing wet undergarments, such as infant diapers and adult incontinence products, has been historically problematic. Skin damage occurs from wetness (urine) and limited product breathability. Evaporative water loss has been measured on adult arms (armband method) or infant torsos (on-baby method), after wearing a saline-insulted diaper product. The current study developed a reliable in vitro method of evaluating diaper and incontinence products for improvements in skin dryness. A simulated skin substrate was applied to a heated mechanical arm or baby torso. A disposable diaper or incontinence product was wrapped around the arm or baby torso, and loaded with saline. Hydration of the simulated skin was measured by evaporimetry and compared with clinical data from adult armband evaluations. The heated mechanical arm and baby torso accurately distinguished products for skin dryness. Eight diaper products were evaluated and compared to human test results. The torso in vitro and mechanical arm evaluations demonstrated strong correlations to human epidermal water loss evaluations, with repeatable results. Additionally, the bench test has been used for adult incontinence products, and it proved to differentiate those products as well as infant products. A rapid and reliable means of evaluation has been developed, and it is predictive of human subject testing. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Heat transfer coefficient: Medivance Arctic Sun Temperature Management System vs. water immersion.

Science.gov (United States)

English, M J; Hemmerling, T M

2008-07-01

To improve heat transfer, the Medivance Arctic Sun Temperature Management System (Medivance, Inc., Louisville, CO, USA) features an adhesive, water-conditioned, highly conductive hydrogel pad for intimate skin contact. This study measured and compared the heat transfer coefficient (h), i.e. heat transfer efficiency, of this pad (hPAD), in a heated model and in nine volunteers' thighs; and of 10 degrees C water (hWATER) in 33 head-out immersions by 11 volunteers. Volunteer studies had ethical approval and written informed consent. Calibrated heat flux transducers measured heat flux (W m-2). Temperature gradient (DeltaT) was measured between skin and pad or water temperatures. Temperature gradient was changed through the pad's water temperature controller or by skin cooling on immersion. The heat transfer coefficient is the slope of W m-2/DeltaT: its unit is W m-2 degrees C-1. Average with (95% CI) was: model, hPAD = 110.4 (107.8-113.1), R2 = 0.99, n = 45; volunteers, hPAD = 109.8 (95.5-124.1), R2 = 0.83, n = 51; and water immersion, hWATER = 107.1 (98.1-116), R2 = 0.86, n = 94. The heat transfer coefficient for the pad was the same in the model and volunteers, and equivalent to hWATER. Therefore, for the same DeltaT and heat transfer area, the Arctic Sun's heat transfer rate would equal water immersion. This has important implications for body cooling/rewarming rates.

Skin Necrosis with Oculomotor Nerve Palsy Due to a Hyaluronic Acid Filler Injection

Directory of Open Access Journals (Sweden)

Jae Il Lee

2017-07-01

Full Text Available Performing rhinoplasty using filler injections, which improve facial wrinkles or soft tissues, is relatively inexpensive. However, intravascular filler injections can cause severe complications, such as skin necrosis and visual loss. We describe a case of blepharoptosis and skin necrosis caused by augmentation rhinoplasty and we discuss the patient’s clinical progress. We describe the case of a 25-year-old female patient who experienced severe pain, blepharoptosis, and decreased visual acuity immediately after receiving a filler injection. Our case suggests that surgeons should be aware of nasal vascularity before performing an operation, and that they should avoid injecting fillers at a high pressure and/or in excessive amounts. Additionally, filler injections should be stopped if the patient complains of severe pain, and appropriate measures should be taken to prevent complications caused by intravascular filler injections.

A Case of Peeling Skin Syndrome.

Science.gov (United States)

Singhal, Anil K; Yadav, Devendra K; Soni, Bajrang; Arya, Savita

2017-01-01

Peeling skin syndrome is a very rare autosomal recessive disease characterized by widespread painless peeling of the skin in superficial sheets. Etiology is still unknown with an autosomal recessive inheritance. Less than 100 cases have been reported in the medical literature. We present a 32-year-old man having asymptomatic peeling of skin since birth. Sheets of skin were peeling from his neck, trunk, and extremities, following friction or rubbing especially if pre-soaked in water but sparing palm and soles. Histologically, there was epidermal separation at the level of stratum corneum, just above the stratum granulosum. This case is being presented due to its rarity.

A case of peeling skin syndrome

Directory of Open Access Journals (Sweden)

Anil K Singhal

2017-01-01

Full Text Available Peeling skin syndrome is a very rare autosomal recessive disease characterized by widespread painless peeling of the skin in superficial sheets. Etiology is still unknown with an autosomal recessive inheritance. Less than 100 cases have been reported in the medical literature. We present a 32-year-old man having asymptomatic peeling of skin since birth. Sheets of skin were peeling from his neck, trunk, and extremities, following friction or rubbing especially if pre-soaked in water but sparing palm and soles. Histologically, there was epidermal separation at the level of stratum corneum, just above the stratum granulosum. This case is being presented due to its rarity.

Projected changes in atmospheric heating due to changes in fire disturbance and the snow season in the western Arctic, 2003-2100

Science.gov (United States)

E.S. Euskirchen; A.D. McGuire; T.S. Rupp; F.S. Chapin; J.E. Walsh

2009-01-01

In high latitudes, changes in climate impact fire regimes and snow cover duration, altering the surface albedo and the heating of the regional atmosphere. In the western Arctic, under four scenarios of future climate change and future fire regimes (2003-2100), we examined changes in surface albedo and the related changes in regional atmospheric heating due to: (1)...

MONITORING SPATIOTEMPORAL CHANGES OF HEAT ISLAND IN BABOL CITY DUE TO LAND USE CHANGES

Directory of Open Access Journals (Sweden)

S. K. Alavi Panah

2017-09-01

Full Text Available Urban heat island is one of the most vital environmental risks in urban areas. The advent of remote sensing technology provides better visibility due to the integrated view, low-cost, fast and effective way to study and monitor environmental and humanistic changes. The aim of this study is a spatiotemporal evaluation of land use changes and the heat island in the time period of 1985-2015 for the studied area in the city of Babol. For this purpose, multi-temporal Landsat images were used in this study. For calculating the land surface temperature (LST, single-channel and maximum likelihood algorithms were used, to classify Images. Therefore, land use changes and LST were examined, and thereby the relationship between land-use changes was analyzed with the normalized LST. By using the average and standard deviation of normalized thermal images, the area was divided into five temperature categories, inter alia, very low, low, medium, high and very high and then, the heat island changes in the studied time period were investigated. The results indicate that land use changes for built-up lands increased by 92%, and a noticeable decrease was observed for agricultural lands. The Built-up land changes trend has direct relation with the trend of normalized surface temperature changes. Low and very low-temperature categories which follow a decreasing trend, are related to lands far away from the city. Also, high and very high-temperature categories whose areas increase annually, are adjacent to the city center and exit ways of the town. The results emphasize on the importance of attention of urban planners and managers to the urban heat island as an environmental risk.

Monitoring Spatiotemporal Changes of Heat Island in Babol City due to Land Use Changes

Science.gov (United States)

Alavi Panah, S. K.; Kiavarz Mogaddam, M.; Karimi Firozjaei, M.

2017-09-01

Urban heat island is one of the most vital environmental risks in urban areas. The advent of remote sensing technology provides better visibility due to the integrated view, low-cost, fast and effective way to study and monitor environmental and humanistic changes. The aim of this study is a spatiotemporal evaluation of land use changes and the heat island in the time period of 1985-2015 for the studied area in the city of Babol. For this purpose, multi-temporal Landsat images were used in this study. For calculating the land surface temperature (LST), single-channel and maximum likelihood algorithms were used, to classify Images. Therefore, land use changes and LST were examined, and thereby the relationship between land-use changes was analyzed with the normalized LST. By using the average and standard deviation of normalized thermal images, the area was divided into five temperature categories, inter alia, very low, low, medium, high and very high and then, the heat island changes in the studied time period were investigated. The results indicate that land use changes for built-up lands increased by 92%, and a noticeable decrease was observed for agricultural lands. The Built-up land changes trend has direct relation with the trend of normalized surface temperature changes. Low and very low-temperature categories which follow a decreasing trend, are related to lands far away from the city. Also, high and very high-temperature categories whose areas increase annually, are adjacent to the city center and exit ways of the town. The results emphasize on the importance of attention of urban planners and managers to the urban heat island as an environmental risk.

Visualizing radiofrequency-skin interaction using multiphoton microscopy in vivo.

Science.gov (United States)

Tsai, Tsung-Hua; Lin, Sung-Jan; Lee, Woan-Ruoh; Wang, Chun-Chin; Hsu, Chih-Ting; Chu, Thomas; Dong, Chen-Yuan

2012-02-01

Redundant skin laxity is a major feature of aging. Recently, radiofrequency has been introduced for nonablative tissue tightening by volumetric heating of the deep dermis. Despite the wide range of application based on this therapy, the effect of this technique on tissue and the subsequent tissue remodeling have not been investigated in detail. Our objective is to evaluate the potential of non-linear optics, including multiphoton autofluorescence and second harmonic generation (SHG) microscopy, as a non-invasive imaging modality for the real-time study of radiofrequency-tissue interaction. Electro-optical synergy device (ELOS) was used as the radiofrequency source in this study. The back skin of nude mouse was irradiated with radiofrequency at different passes. We evaluated the effect on skin immediately and 1 month after treatment with multiphoton microscopy. Corresponding histology was performed for comparison. We found that SHG is negatively correlated to radiofrequency passes, which means that collagen structural disruption happens immediately after thermal damage. After 1 month of collagen remodeling, SHG signals increased above baseline, indicating that collagen regeneration has occurred. Our findings may explain mechanism of nonablative skin tightening and were supported by histological examinations. Our work showed that monitoring the dermal heating status of RF and following up the detailed process of tissue reaction can be imaged and quantified with multiphoton microscopy non-invasively in vivo. Copyright © 2011. Published by Elsevier Ireland Ltd.

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.

Natural considerations for skin of color.

Science.gov (United States)

Baumann, Leslie; Rodriguez, David; Taylor, Susan C; Wu, Jessica

2006-12-01

Changing US demographics indicate that dermatologists will treat an increasing number of individuals of color. Early research on cutaneous anatomy and physiology was performed mostly in white populations. However, new research is elucidating similarities and differences in skin of color and white skin with regard to skin barrier, pigmentation, and sensitivity. Two of the most important issues are skin lightening and brightening. Products for use on skin of color typically should be gentle because of the proclivity of more deeply pigmented skin to develop pigmentary abnormalities in response to skin irritation or trauma. Increasing patient interest in natural remedies has been matched by research on the use of natural ingredients in dermatology. The relative gentleness of many of these products, coupled with excellent efficacy, makes natural ingredients such as soy and licorice excellent choices in the treatment of disorders such as postinflammatory hyperpigmentation (PIH) and melasma. For daily skin care, ingredients such as oatmeal and feverfew are good choices for gentle cleansing and moisturizing of dry, sensitive, or ashy skin. Sun protection is an increasing concern due to rising rates of melanoma. Several botanical products are useful in augmenting photoprotection with conventional sunscreens.

Skin tightening technologies.

Science.gov (United States)

Greene, Ryan M; Green, Jeremy B

2014-02-01

Radiofrequency (RF) and intense focused ultrasound (IFUS) are increasingly used to address skin laxity of the face and neck. Both nonablative RF and ultrasound create a heat-induced tissue response that leads to collagen remodeling and other ultrastructural changes. Although these treatments are not meant to replace surgical procedures, patient satisfaction in the majority of studies has been consistently high. This article discusses the various RF and IFUS technologies currently in use and reviews pertinent clinical studies evaluating their efficacy and safety. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Electrochemical monitoring of native catalase activity in skin using skin covered oxygen electrode.

Science.gov (United States)

Nocchi, Sarah; Björklund, Sebastian; Svensson, Birgitta; Engblom, Johan; Ruzgas, Tautgirdas

2017-07-15

A skin covered oxygen electrode, SCOE, was constructed with the aim to study the enzyme catalase, which is part of the biological antioxidative system present in skin. The electrode was exposed to different concentrations of H 2 O 2 and the amperometric current response was recorded. The observed current is due to H 2 O 2 penetration through the outermost skin barrier (referred to as the stratum corneum, SC) and subsequent catalytic generation of O 2 by catalase present in the underlying viable epidermis and dermis. By tape-stripping the outermost skin layers we demonstrate that SC is a considerable diffusion barrier for H 2 O 2 penetration. Our experiments also indicate that skin contains a substantial amount of catalase, which is sufficient to detoxify H 2 O 2 that reaches the viable epidermis after exposure of skin to high concentrations of peroxide (0.5-1mM H 2 O 2 ). Further, we demonstrate that the catalase activity is reduced at acidic pH, as compared with the activity at pH 7.4. Finally, experiments with often used penetration enhancer thymol shows that this compound interferes with the catalase reaction. Health aspect of this is briefly discussed. Summarizing, the results of this work show that the SCOE can be utilized to study a broad spectrum of issues involving the function of skin catalase in particular, and the native biological antioxidative system in skin in general. Copyright © 2017 Elsevier B.V. All rights reserved.

Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans

OpenAIRE

Wingo, Jonathan E.; Low, David A.; Keller, David M.; Brothers, R. Matthew; Shibasaki, Manabu; Crandall, Craig G.

2010-01-01

Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdial...

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.

Skin Cancer Concerns in People of Color: Risk Factors and Prevention

Science.gov (United States)

Gupta, Alpana K; Bharadwaj, Mausumi; Mehrotra, Ravi

2016-01-01

Background: Though people of color (POC) are less likely to become afflicted with skin cancer, they are much more likely to die from it due to delay in detection or presentation. Very often, skin cancer is diagnosed at a more advanced stage in POC, making treatment difficult. The purpose of this research was to improve awareness regarding skin cancers in people of color by providing recommendations to clinicians and the general public for early detection and photo protection preventive measures. Methods: Data on different types of skin cancers were presented to POC. Due to limited research, there are few resources providing insights for evaluating darkly pigmented lesions in POC. Diagnostic features for different types of skin cancers were recorded and various possible risk factors were considered. Results: This study provided directions for the prevention and early detection of skin cancer in POC based on a comprehensive review of available data. Conclusions: The increased morbidity and mortality rate associated with skin cancer in POC is due to lack of awareness, diagnosis at a more advanced stage and socioeconomic barriers hindering access to care. Raising public health concerns for skin cancer prevention strategies for all people, regardless of ethnic background and socioeconomic status, is the key to timely diagnosis and treatment. PMID:28125871

Light and skin disease

International Nuclear Information System (INIS)

Bauer, R.

1991-01-01

Because of the depletion of ozone in the stratosphere due to chlorofluorocarbons, the screening effect of this ozone layer on ultraviolet radiation (especially the so-called UV-B component) is reduced. This paper describes the impact of increased UV radiation on the human skin. Because of the 'ozone-hole', a distinct increase in the rate of skin cancer is to be expected which will affect all living beings but most of all man - an indirect consequence of the climate development. What makes the increased intensity of UV-B radiation so harmful is the fact that light-induced skin damage accumulates for the period of the life-time of the individual and cannot be reversed. A further thinning of stratospheric ozone would let through, in addition, the more short-waved ('harder') UV-C radiation. The latter, though clinically not significant currently, would then account for a further increase in the rate of malignant skin disease world-wide. (orig.) [de

Infrared reflectometry of skin: Analysis of backscattered light from different skin layers

Science.gov (United States)

Pleitez, Miguel A.; Hertzberg, Otto; Bauer, Alexander; Lieblein, Tobias; Glasmacher, Mathias; Tholl, Hans; Mäntele, Werner

2017-09-01

We have recently reported infrared spectroscopy of human skin in vivo using quantum cascade laser excitation and photoacoustic or photothermal detection for non-invasive glucose measurement . Here, we analyze the IR light diffusely reflected from skin layers for spectral contributions of glucose. Excitation of human skin by an external cavity tunable quantum cascade laser in the spectral region from 1000 to 1245 cm- 1, where glucose exhibits a fingerprint absorption, yields reflectance spectra with some contributions from glucose molecules. A simple three-layer model of skin was used to calculate the scattering intensities from the surface and from shallow and deeper layers using the Boltzmann radiation transfer equation. Backscattering of light at wavelengths around 10 μm from the living skin occurs mostly from the Stratum corneum top layers and the shallow layers of the living epidermis. The analysis of the polarization of the backscattered light confirms this calculation. Polarization is essentially unchanged; only a very small fraction (light is due to specular reflectance and to scattering from layers close to the surface. Diffusely reflected light from deeper layers undergoing one or more scattering processes would appear with significantly altered polarization. We thus conclude that a non-invasive glucose measurement based on backscattering of IR light from skin would have the drawback that only shallow layers containing some glucose at concentrations only weakly related to blood glucose are monitored.

Keratinocytes propagated in serum-free, feeder-free culture conditions fail to form stratified epidermis in a reconstituted skin model.

Directory of Open Access Journals (Sweden)

Rebecca Lamb

Full Text Available Primary human epidermal stem cells isolated from skin tissues and subsequently expanded in tissue culture are used for human therapeutic use to reconstitute skin on patients and to generate artificial skin in culture for academic and commercial research. Classically, epidermal cells, known as keratinocytes, required fibroblast feeder support and serum-containing media for serial propagation. In alignment with global efforts to remove potential animal contaminants, many serum-free, feeder-free culture methods have been developed that support derivation and growth of these cells in 2-dimensional culture. Here we show that keratinocytes grown continually in serum-free and feeder-free conditions were unable to form into a stratified, mature epidermis in a skin equivalent model. This is not due to loss of cell potential as keratinocytes propagated in serum-free, feeder-free conditions retain their ability to form stratified epidermis when re-introduced to classic serum-containing media. Extracellular calcium supplementation failed to improve epidermis development. In contrast, the addition of serum to commercial, growth media developed for serum-free expansion of keratinocytes facilitated 3-dimensional stratification in our skin equivalent model. Moreover, the addition of heat-inactivated serum improved the epidermis structure and thickness, suggesting that serum contains factors that both aid and inhibit stratification.

Modeling and analyzing flow of third grade nanofluid due to rotating stretchable disk with chemical reaction and heat source

Science.gov (United States)

Hayat, T.; Ahmad, Salman; Khan, M. Ijaz; Alsaedi, A.

2018-05-01

This article addresses flow of third grade nanofluid due to stretchable rotating disk. Mass and heat transports are analyzed through thermophoresis and Brownian movement effects. Further the effects of heat generation and chemical reaction are also accounted. The obtained ODE's are tackled computationally by means of homotopy analysis method. Graphical outcomes are analyzed for the effects of different variables. The obtained results show that velocity reduces through Reynolds number and material parameters. Temperature and concentration increase with Brownian motion and these decrease by Reynolds number.

Entropy generation due to external fluid flow and heat transfer from a cylinder between parallel planes

Directory of Open Access Journals (Sweden)

Melhem Omar A.

2017-01-01

Full Text Available In the present study, second law analysis is introduced for circular cylinder confined between parallel planes. An analytical approach is adopted to study the effects of block age, Reynolds and Prandtl numbers on the entropy generation due to the laminar flow and heat transfer. Four different fluids are considered in the present analysis for comparison purposes. Heat transfer for the cylinder at an isothermal boundary condition is incorporated. In general, the entropy generation rate decreases as the blockage ratio decreases. In addition, the entropy generation rate increases with increasing Reynolds and Prandtl numbers. At a fixed Reynolds number, the effect of block age becomes more notice able for higher Prandtl number fluid. Similarly, for the same fluid, the effect of block age becomes more no tice able as the Reynolds number increases.

Heat transfer

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Heat transfer. Heat conduction in solid slab. Convective heat transfer. Non-linear temperature. variation due to flow. HEAT FLUX AT SURFACE. conduction/diffusion.

Shock-induced heating and millisecond boiling in gels and tissue due to high intensity focused ultrasound

Science.gov (United States)

Canney, Michael S.; Khokhlova, Vera A.; Bessonova, Olga V.; Bailey, Michael R.; Crum, Lawrence A.

2009-01-01

Nonlinear propagation causes high intensity ultrasound waves to distort and generate higher harmonics, which are more readily absorbed and converted to heat than the fundamental frequency. Although such nonlinear effects have previously been investigated and found not to significantly alter high intensity focused ultrasound (HIFU) treatments, two results reported here change this paradigm. One is that at clinically relevant intensity levels, HIFU waves not only become distorted but form shock waves in tissue. The other is that the generated shock waves heat the tissue to boiling in much less time than predicted for undistorted or weakly distorted waves. In this study, a 2-MHz HIFU source operating at peak intensities up to 25,000 W/cm2 was used to heat transparent tissue-mimicking phantoms and ex vivo bovine liver samples. Initiation of boiling was detected using high-speed photography, a 20-MHz passive cavitation detector, and fluctuation of the drive voltage at the HIFU source. The time to boil obtained experimentally was used to quantify heating rates and was compared to calculations using weak shock theory and the shock amplitudes obtained from nonlinear modeling and from measurements with a fiber optic hydrophone. As observed experimentally and predicted by calculations, shocked focal waveforms produced boiling in as little as 3 ms and the time to initiate boiling was sensitive to small changes in HIFU output. Nonlinear heating due to shock waves is therefore important to HIFU and clinicians should be aware of the potential for very rapid boiling since it alters treatments. PMID:20018433

Bizarre behavior of heat capacity in crystals due to interplay between two types of anharmonicities.

Science.gov (United States)

Yurchenko, Stanislav O; Komarov, Kirill A; Kryuchkov, Nikita P; Zaytsev, Kirill I; Brazhkin, Vadim V

2018-04-07

The heat capacity of classical crystals is determined by the Dulong-Petit value C V ≃ D (where D is the spatial dimension) for softly interacting particles and has the gas-like value C V ≃ D/2 in the hard-sphere limit, while deviations are governed by the effects of anharmonicity. Soft- and hard-sphere interactions, which are associated with the enthalpy and entropy of crystals, are specifically anharmonic owing to violation of a linear relation between particle displacements and corresponding restoring forces. Here, we show that the interplay between these two types of anharmonicities unexpectedly induces two possible types of heat capacity anomalies. We studied thermodynamics, pair correlations, and collective excitations in 2D and 3D crystals of particles with a limited range of soft repulsions to prove the effect of interplay between the enthalpy and entropy types of anharmonicities. The observed anomalies are triggered by the density of the crystal, changing the interaction regime in the zero-temperature limit, and can provide about 10% excess of the heat capacity above the Dulong-Petit value. Our results facilitate understanding effects of complex anharmonicity in molecular and complex crystals and demonstrate the possibility of new effects due to the interplay between different types of anharmonicities.

Excessive heat removal due to feedwater system malfunction

International Nuclear Information System (INIS)

Beader, D.; Peterlin, G.

1986-01-01

Excessive heat removal transient of the Krsko Nuclear Power Plant, caused by steam generators feedwater system malfunctions was simulated by RELAP5/MOD1 computer code. The results are increase of power and reactor scram caused by high-high steam generator level. (author)

Cutaneous C-polymodal fibers lacking TRPV1 are sensitized to heat following inflammation, but fail to drive heat hyperalgesia in the absence of TPV1 containing C-heat fibers

Directory of Open Access Journals (Sweden)

Koerber H Richard

2010-09-01

Full Text Available Abstract Background Previous studies have shown that the TRPV1 ion channel plays a critical role in the development of heat hyperalgesia after inflammation, as inflamed TRPV1-/- mice develop mechanical allodynia but fail to develop thermal hyperalgesia. In order to further investigate the role of TRPV1, we have used an ex vivo skin/nerve/DRG preparation to examine the effects of CFA-induced-inflammation on the response properties of TRPV1-positive and TRPV1-negative cutaneous nociceptors. Results In wildtype mice we found that polymodal C-fibers (CPMs lacking TRPV1 were sensitized to heat within a day after CFA injection. This sensitization included both a drop in average heat threshold and an increase in firing rate to a heat ramp applied to the skin. No changes were observed in the mechanical response properties of these cells. Conversely, TRPV1-positive mechanically insensitive, heat sensitive fibers (CHs were not sensitized following inflammation. However, results suggested that some of these fibers may have gained mechanical sensitivity and that some previous silent fibers gained heat sensitivity. In mice lacking TRPV1, inflammation only decreased heat threshold of CPMs but did not sensitize their responses to the heat ramp. No CH-fibers could be identified in naïve nor inflamed TRPV1-/- mice. Conclusions Results obtained here suggest that increased heat sensitivity in TRPV1-negative CPM fibers alone following inflammation is insufficient for the induction of heat hyperalgesia. On the other hand, TRPV1-positive CH fibers appear to play an essential role in this process that may include both afferent and efferent functions.

Emerging treatment options for acute bacterial skin and skin structure infections: focus on intravenous delafloxacin

Directory of Open Access Journals (Sweden)

Righi E

2018-04-01

Full Text Available Elda Righi, Alessia Carnelutti, Antonio Vena, Matteo Bassetti Infectious Diseases Division, Santa Maria della Misericordia University Hospital, Udine, Italy Abstract: The increase in hospitalization due to acute bacterial skin and skin structure infections (ABSSSI caused by resistant pathogens supports the need for new treatment options. Antimicrobial options for ABSSSI that provide broad-spectrum coverage, including gram-negative pathogens and multidrug-resistant gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA, are limited. Delafloxacin is a novel fluoroquinolone available as intravenous and oral formulations and is characterized by an increased efficacy in acidic environments and activity on bacterial biofilm. Delafloxacin displays enhanced in vitro activity against MRSA, and enterococci, while maintaining efficacy against gram-negative pathogens and anaerobes. Delafloxacin has been studied for the treatment of ABSSSI and respiratory infections. Phase III studies have demonstrated noninferiority of delafloxacin compared to vancomycin, linezolid, tigecycline, and the combination of vancomycin plus aztreonam in the treatment of ABSSSI. Due to its favorable pharmacokinetic characteristics, the wide spectrum of action, and the potential for sequential therapy, delafloxacin represents a promising option in the empirical and targeted treatment of ABSSSI, both in hospital- and in community-based care. Keywords: bacterial skin and skin structure infections, multidrug-resistant bacteria, methicillin-resistant Staphylococcus aureus, delafloxacin

A model for allometric scaling of mammalian metabolism with ambient heat loss

KAUST Repository

Kwak, Ho Sang

2016-02-02

Background Allometric scaling, which represents the dependence of biological trait or process relates on body size, is a long-standing subject in biological science. However, there has been no study to consider heat loss to the ambient and an insulation layer representing mammalian skin and fur for the derivation of the scaling law of metabolism. Methods A simple heat transfer model is proposed to analyze the allometry of mammalian metabolism. The present model extends existing studies by incorporating various external heat transfer parameters and additional insulation layers. The model equations were solved numerically and by an analytic heat balance approach. Results A general observation is that the present heat transfer model predicted the 2/3 surface scaling law, which is primarily attributed to the dependence of the surface area on the body mass. External heat transfer effects introduced deviations in the scaling law, mainly due to natural convection heat transfer which becomes more prominent at smaller mass. These deviations resulted in a slight modification of the scaling exponent to a value smaller than 2/3. Conclusion The finding that additional radiative heat loss and the consideration of an outer insulation fur layer attenuate these deviation effects and render the scaling law closer to 2/3 provides in silico evidence for a functional impact of heat transfer mode on the allometric scaling law in mammalian metabolism.

Skin Barrier Function and Allergens

DEFF Research Database (Denmark)

Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan

2016-01-01

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

Relationship between physical attributes and heat stress in dairy cattle from different genetic groups

Science.gov (United States)

Alfonzo, Evelyn Priscila München; Barbosa da Silva, Marcos Vinicius Gualberto; dos Santos Daltro, Darlene; Stumpf, Marcelo Tempel; Dalcin, Vanessa Calderaro; Kolling, Giovani; Fischer, Vivian; McManus, Concepta Margaret

2016-02-01

Dairy cattle raised under harsh conditions have to adapt and prevent heat stress. The aim of this study was to evaluate physical characteristics and their association with heat tolerance in different genetic groups of dairy cattle. Thickness of the skin and coat, length and number of hairs, body measurements, as well as physiological parameters and body temperatures by infrared thermography were determined in 19 Holstein and 19 Girolando (½ and ¾ Holstein) cows. The Holstein cattle were less tolerant to heat stress than Girolando (GH50 and GH75 Holstein), because of the difficulty in dissipating heat due to the larger body size, as well as thicker and longer hairs. The correlations between physical characteristics, physiological parameters, and thermographic measurements prove to be inconsistent among genetic groups and therefore are not predictive of heat tolerance, while the regressions of morphometric characteristics on physiological and thermographic measures were not significant. Thus, the physical characteristics were not good predictors of physiological indices and thermographic temperature and so should not be used.

Radon dose to the skin and the possible induction of skin cancers

International Nuclear Information System (INIS)

Eatough, J.P.; Henshaw, D.L.

1991-01-01

The radon related alpha particle dose equivalent to the basal layer of the epidermis has been calculated and found to be at least 2 mSv.y -1 , for exposed skin at the UK average radon exposure of 20 Bq.m -3 . A considerably greater dose equivalent may be received at this same radon concentration depending on the plateout conditions. Using standard risk factors 13% of skin cancers would theoretically be attributed to radon at the UK average exposure of 20 Bq.m -3 . Direct studies of skin cancer and radon in the home are needed before the validity of this prediction can be established. There is little evidence from high dose studies suggesting the induction of malignant melanoma by ionising radiation, although some circumstantial evidence exists, and the possibility that radon may be a co-factor with UV light in the induction of malignant melanoma, should not be dismissed. Due to the nature of the radiation risk factors the majority of any skin cancers linked to radon will simultaneously be linked to ultraviolet light exposure. (author)

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.

Evaluation of heat transfer tube failure propagation due to sodium-water reaction in steam generator

International Nuclear Information System (INIS)

Nei, Hiromichi

1978-01-01

An evaluation was made of heat transfer tube failure propagation due to sodium-water reaction wastage in a sodium heated steam generator, by comparing an empirically derived wastage equation with leak detector responses. The experimental data agreed well with the wastage equation even for different values of distance-to-nozzle diameter ratio, though the formula had been based on wastage data obtained for only one given distance. The time taken for failure propagation was estimated for a prototype steam generator, and compared with the responses characteristics of acoustic detectors and level gages. It was found that there exists a range of leak rate between 0.5 and 100 g/sec, where the level gage can play a useful role in leak detection. The acoustic detector can be expected to respond more rapidly than the cover gas pressure gage, if noise is kept below ten times the value observed in an experimental facility, SWAT-2. (auth.)

Advanced tools for in vivo skin analysis.

Science.gov (United States)

Cal, Krzysztof; Zakowiecki, Daniel; Stefanowska, Justyna

2010-05-01

A thorough examination of the skin is essential for accurate disease diagnostics, evaluation of the effectiveness of topically applied drugs and the assessment of the results of dermatologic surgeries such as skin grafts. Knowledge of skin parameters is also important in the cosmetics industry, where the effects of skin care products are evaluated. Due to significant progress in the electronics and computer industries, sophisticated analytic devices are increasingly available for day-to-day diagnostics. The aim of this article is to review several advanced methods for in vivo skin analysis in humans: magnetic resonance imaging, electron paramagnetic resonance, laser Doppler flowmetry and time domain reflectometry. The molecular bases of these techniques are presented, and several interesting applications in the field are discussed. Methods for in vivo assessment of the biomechanical properties of human skin are also reviewed.

Opportunities for Skin Cancer Prevention Education among Individuals Attending a Community Skin Cancer Screening in a High-Risk Catchment Area.

Science.gov (United States)

Parsons, Bridget Grahmann; Gren, Lisa H; Simonsen, Sara E; Harding, Garrett; Grossman, Douglas; Wu, Yelena P

2018-04-01

Despite the highly preventable nature of skin cancer, it remains the most commonly diagnosed form of cancer in the United States. Recommendations for a complete skin cancer prevention regimen include engaging in photoprotection (e.g., sunscreen use), avoiding skin cancer risk behaviors (e.g., tanning), and receiving total body skin exams from a health care provider. The current study examined reported engagement in these behaviors among participants attending a community skin cancer screening (N = 319) in a high-risk catchment area to assess the need for increased health education on skin cancer prevention. Participants' responses indicate a history of suboptimal avoidance of skin cancer risk behaviors. Over half of participants (52%) reported four or more blistering sunburns before age 20, and 46% reported indoor tanning at least one during their lifetime. There is a need among this population for education regarding a complete skin cancer prevention regimen, which could improve adherence to photoprotection and avoidance of skin cancer risk behaviors, thereby reducing morbidity and mortality due to skin cancer.

Thermoregulatory efficiency is increased after heat acclimation in tropical natives.

Science.gov (United States)

Magalhães, Flávio C; Passos, Renata L F; Fonseca, Michele A; Oliveira, Kenya P M; Ferreira-Júnior, João B; Martini, Angelo R P; Lima, Milene R M; Guimarães, Juliana B; Baraúna, Valério G; Silami-Garcia, Emerson; Rodrigues, Luiz O C

2010-01-01

To evaluate the effects of heat acclimation on sweat rate redistribution and thermodynamic parameters, 9 tropical native volunteers were submitted to 11 days of exercise-heat exposures (40+/-0 degrees C and 45.1+/-0.2% relative humidity). Sudomotor function was evaluated by measuring total and local (forehead, chest, arm, forearm, and thigh) sweat rates, local sweat sodium concentration, and mean skin and rectal temperatures. We also calculated heat production (H), heat storage (S), heat exchange by radiation (R) and by convection (C), evaporated sweat (E(sw)), sweating efficiency (eta(sw)), skin wettedness (w(sk)), and the ratio between the heat storage and the sum of heat production and heat gains by radiation and convection (S/(H+R+C)). The heat acclimation increased the whole-body sweat rate and reduced the mean skin temperature. There were changes in the local sweat rate patterns: on the arm, forearm, and thigh it increased significantly from day 1 to day 11 (all p<0.05) and the sweat rates from the forehead and the chest showed a small nonsignificant increase (p=0.34 and 0.17, respectively). The relative increase of local sweat rates on day 11 was not different among the sites; however, when comparing the limbs (arm, forearm, and thigh) with the trunk (forehead and chest), there was a significant higher increase in the limbs (32+/-5%) in comparison to the trunk (11+/-2%, p=0.001). After the heat acclimation period we observed higher w(sk) and E(sw) and reduced S/(H+R+C), meaning greater thermoregulatory efficiency. The increase in the limb sweat rate, but not the increase in the trunk sweat rate, correlated with the increased w(sk), E(sw), and reduced S/(H+R+C) (p<0.05 to all). Altogether, it can be concluded that heat acclimation increased the limbs' sweat rates in tropical natives and that this increase led to increased loss of heat through evaporation of sweat and this higher sweat evaporation was related to higher thermoregulatory efficiency.

Newtonian heating effect on unsteady hydromagnetic Casson fluid flow past a flat plate with heat and mass transfer

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M. Das

2015-12-01

Full Text Available The influence of Newtonian heating on heat and mass transfer in unsteady hydromagnetic flow of a Casson fluid past a vertical plate in the presence of thermal radiation and chemical reaction is studied. The Casson fluid model is used to distinguish the non-Newtonian fluid behavior. The fluid flow is induced due to periodic oscillations of the plate along its length and a uniform transverse magnetic field is applied in a direction which is normal to the direction of fluid flow. The partial differential equations governing the flow, heat, and mass transfer are transformed to non-dimensional form using suitable non-dimensional variables which are then solved analytically by using Laplace transform technique. The numerical values of the fluid velocity, fluid temperature, and species concentration are depicted graphically whereas the values of skin-friction, Nusselt number, and Sherwood number are presented in tabular form. It is noticed that the fluid velocity and temperature decrease with increasing values of Casson parameter while concentration decreases with increasing values of chemical reaction parameter and Schmidt number. Such a fluid flow model has several industrial and medical applications such as in glass manufacturing, paper production, purification of crude oil and study of blood flow in the cardiovascular system.

Skin decontamination of G, V, H L agents by Canadian reactive skin decontaminant lotion

Energy Technology Data Exchange (ETDEWEB)

Bide, R.W.; Sawyer, T.W.; DiNinno, V.L.; Armour, S.J.; Risk, D.J.

1993-05-13

The Canadian Reactive Skin Decontaminant Lotion (RSDL) is a reactive solution designed to be applied directly to skin for the decontamination and destruction of the classical chemical warfare agents. The solvent of the RSDL is very effective in dissolving liquid agents from the skin surface and the differential solubility of agents in the RSDL and the skin strongly favors retention of agents in the lotion. The active ingredient in the RSDL reacts rapidly and completely with G-agents, V-agents, mustard Lewisite producing relatively nontoxic products. The RSDL will dissolve and destroy agent thickened with acrylate polymers. The lotion is water soluble and readily removed from the skin. Since the RSDL is water soluble, it is active against water soluble agents even at high dilutions. For water insoluble agents, the activity is reduced as the water content rises above abrasive 50% due to insolubility of the agents. Skin and eye irritancy trials indicate that the RSDL is only a mild irritant to the eyes (equivalent to a chlorinated swimming pool) and to abraded skin. Acute toxicity trials showed that large oral and intraperitoneal doses were essentially non-toxic. The RSDL was fielded by the Canadian Forces for the Gulf Conflict. The RSDL may be used in open wounds for short periods. Wound decontamination and irrigation with RSDL diluted 1:1 with isotonic saline was recommended for the Gulf conflict.

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

Skin Protective Nutraceuticals: The Current Evidence in Brief

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Oroma Nwanodi

2018-05-01

Full Text Available Nutraceuticals are important for healthy skin maintenance. Probiotics, phenolics, and vitamins are just a few of the nutraceuticals meant to potentially prevent and assist medical management of dermatologic conditions. Among these, probiotics, vitamin E, and green tea catechins may offer the broadest array of skin protective mechanisms with probiotics having the greatest clinical range. Probiotics’ amelioration of atopic dermatitis and opportunistic infections of skin burns has been targeted in recent research efforts. This includes the improvement of Scoring Atopic Dermatitis index scores, p = 0.02, with intact Lactobacillus rhamnosus Goldin and Gorbach (LGG in comparison to heat inactivated LGG or placebo. Lactobacillus reuteri used prior to or concurrently with Staphylococcus aureus infection can increase epidermal keratinocyte survival, p < 0.01. Phenolics may not have been extensively studied for atopic dermatitis or skin burns. However, phenolics do have a role in photoprotection. The phenolic rutin increases ultraviolet B radiation filter reactive oxygen species scavenging at 75%, p < 0.002, and peak wavelength absorption, p < 0.001. While oral and topical probiotics have untapped potential for atopic dermatitis amelioration and skin infection prevention, phenolics will be increasingly used for photoprotection. With optimized bioavailability, dosage, and formulation, nutraceuticals will become crucial for healthy skin maintenance.

Hyperalgesia and temporal summation of pain after heat injury in man

DEFF Research Database (Denmark)

Pedersen, J L; Andersen, O K; Arendt-Nielsen, L

1998-01-01

of pain in normal skin with summation of pain in skin with primary and secondary hyperalgesia evoked by a heat injury. A heat injury was produced on the crus of 12 volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min). Measurements were made before, and 0, 1, 2, and 4 h after the heat injury......, in three areas: primary and secondary mechanical hyperalgesia induced by the heat injury, and in a mirror image of the injury on the opposite leg. Temporal summation of pain was induced by repeated electrical stimuli (five stimuli at 2 Hz) and assessed by visual analog scale (VAS). Primary hyperalgesia...... was evaluated by von Frey hairs and electrical stimuli, and the areas of secondary hyperalgesia with a rigid von Frey hair (314 mN). Significant primary (P heat injury. The pain threshold to single electrical stimuli was reduced...

Numerical simulations of the effect of an isotropic heat field on the entropy generation due to natural convection in a square cavity

International Nuclear Information System (INIS)

El-Maghlany, Wael M.; Saqr, Khalid M.; Teamah, Mohamed A.

2014-01-01

Highlights: • Entropy generation in laminar natural convection in square cavity numerically studied. • The cavity subjected to an isotropic heat field with different intensities. • Study ranges 10 3 ⩽ Ra ⩽ 10 5 , 0 ⩽ ϕ ⩽ 10 and Pr = 0.7. • Entropy generation drastically affected by the superposition of an isotropic heat field. • CFD based empirical were derived for entropy generation as a function of Ra and φ. - Abstract: Entropy generation associated with laminar natural convection in an infinite square cavity, subjected to an isotropic heat field with different intensities; was numerically investigated for different values of Rayleigh number. The numerical work was carried out using, an in-house CFD code written in FORTRAN, which discretizes non-dimensional forms of the governing equations using the finite volume method and solves the resulting system of equations using Gauss-Seidal method utilizing a TDMA algorithm. Proper code validation was undertaken in order to establish the entropy generation calculations. It was found that the increase in the isotropic heat field intensity resulted in a corresponding exponential increase of the entropy augmentation number, and promoted high values of Bejan number within the flow. The entropy generation due to heat transfer was approximately one order of magnitude higher than the entropy generation due to fluid friction. The spatial uniformity of the Bejan number was more sensitive to the change in Rayleigh number than to the heat field intensity. The thermodynamic penalty of the isotropic heat field is shown by means of global integrals of the entropy source terms over the entire flow domain

Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

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M. R. Monazzam Esmaielpour

2015-09-01

Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. . Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. .Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. .Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is

Non-enzymatic NO production in human skin: effect of UVA on cutaneous NO stores

NARCIS (Netherlands)

Suschek, C.; Opländer, C.; van Faassen, E.E.H.

2009-01-01

Nitric oxide (NO) in human skin has been under investigation since first reports of NOS expression in skin tissue in 1992 [1]. NO plays a key role in the dermal response to external stimuli such as heat, ultraviolet (UV) light, or infection, and in healing of abrasions, lesions or burns. Recently, a

From topical antidote against skin irritants to a novel counter-irritating and anti-inflammatory peptide

International Nuclear Information System (INIS)

Brodsky, Berta; Erlanger-Rosengarten, Avigail; Proscura, Elena; Shapira, Elena; Wormser, Uri

2008-01-01

The primary purpose of the present study was to investigate the mechanism of the counter-irritating activity of topical iodine against skin lesions induced by chemical and thermal stimuli. The hypothesis that iodine exerts its activity by inducing an endogenous anti-inflammatory factor was confirmed by exposing guinea pig skin to heat stimulus followed by topical iodine treatment and skin extraction. Injection of the extract into naive guinea pigs reduced heat-induced irritation by 69%. The protective factor, identified as a new nonapeptide (histone H2A 36-44, H-Lys-Gly-Asn-Tyr-Ala-Glu-Arg-Ileu-Ala-OH), caused reduction of 40% in irritation score in heat-exposed guinea pigs. The murine analog (H-Lys-Gly-His-Tyr-Ala-Glu-Arg-Val-Gly-OH, termed IIIM1) reduced sulfur mustard (SM)-induced ear swelling at a dose-dependent bell-shape manner reaching peak activity of 1 mg/kg. Cultured keratinocytes transfected with the peptide were more resistant towards SM than the control cells. The peptide suppressed oxidative burst in activated neutrophils in a concentration-dependent manner. In addition, the peptide reduced glucose oxidase-induced skin edema in mice at a dose-dependent bell-shape manner. Apart from thermal and chemical-induced skin irritation this novel peptide might be of potential use in chronic dermal disorders such as psoriasis and pemphigus as well as non-dermal inflammatory diseases like multiple sclerosis, arthritis and colitis

Study of skin markers for magnetic resonance imaging examinations

International Nuclear Information System (INIS)

Takatsu, Yasuo; Umezaki, Yoshie; Miyati, Tosiaki; Yamamura, Kenichirou

2013-01-01

In magnetic resonance imaging (MRI), skin markers are used as a landmark in order to make plans for examinations. However, there isn't a lot of research about the material and shape of skin markers. The skin marker's essential elements are safety, good cost performance, high signal intensity for T 1 weighted image (T 1 WI) and T 2 weighted image (T 2 WI), and durable. In order to get a high signal-to-noise ratio (SNR) of T 1 WI and T 2 WI, baby oil, salad oil and olive oil were chosen, because these materials were easy to obtain and safe for the skin. The SNR of baby oil was the best. Baby oil was injected into the infusion tube, and the tube was solvent welded and cut by a heat sealer. In order to make ring shaped skin markers, both ends of the tube were stuck with adhesive tape. Three different diameters of markers were made (3, 5, 10 cmφ). Ring shaped skin markers were put on to surround the examination area, therefore, the edge of the examination area could be seen at every cross section. Using baby oil in the ring shaped infusion tube is simple, easy, and a highly useful skin marker. (author)

Tumors of the skin and soft tissues

Energy Technology Data Exchange (ETDEWEB)

Weller, R.E.

1991-10-01

The majority of the body surface is covered by the skin. Many internal disorders are reflected in the condition of the skin. One of the major functions of the skin is protection of the other organ systems from a variety of environmental insults. In this role, the skin itself is exposed to factors that can ultimately cause chronic diseases and cancer. Since it is relatively easy to recognize skin abnormalities, most skin cancers are brought to professional attention sooner than other types of cancer. However, due to the close resemblance between many skin neoplasms and noncancerous dermatologic disorders, these neoplasms may be mistreated for months or even years. In veterinary oncology, as in human medicine, most cancers can be effectively treated or cured following an accurate diagnosis. Once diagnosed, skin neoplasms should be aggressively treated. If causal factors are known, exposure to these factors should be limited through removal of the agent (for chemical carcinogens) or limiting exposure to the agent (for other carcinogens such as sunlight). 10 tabs. (MHB)

Heat Waves

Science.gov (United States)

Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and spasms due ... that the body is having trouble with the heat. If a heat wave is predicted or happening… - ...

The effect of skin temperature on performance during a 7.5-km cycling time trial

NARCIS (Netherlands)

Levels, K.; de Koning, J.J.; Foster Jr., C.C.; Daanen, H.A.M.

2012-01-01

Aerobic exercise performance is seriously compromised in the heat. Possibly, a high skin temperature causes a rating of perceived exertion (RPE)-mediated decrease in exercise intensity. The purpose of this study was to determine the effect of skin temperature on power output during a 7.5-km cycling

Experimental and numerical study of back-cooling car-seat system using embedded heat pipes to improve passenger’s comfort

International Nuclear Information System (INIS)

Hatoum, Omar; Ghaddar, Nesreen; Ghali, Kamel; Ismail, Nagham

2017-01-01

Graphical abstract: Heat pipe assembly (a) with the insulation layer (b) without the insulation layer; and (c) thermal manikin test on the heat pipe chair. - Highlights: • A new back cooling system for a car seat using embedded heat pipes was modeled numerically. • The heat-pipe seat model was experimentally validated using heated thermal manikin. • An integrated heat pipe model and bio-heat model was used to predict local thermal comfort. • The heat pipe system reduced the back skin temperature by 1 °C compared to seat without heat pipes. • The heat pipe system increased the overall thermal comfort of the passenger by 30%. - Abstract: This work develops a back-cooling system for a car seat using seat embedded heat pipes to improve passenger comfort. The heat pipe system utilizes the temperature difference between the passenger back and the car cabin air to remove heat from the human body and enhance the comfort state. The developed seat heat-pipe model was validated experimentally using a thermal manikin with controlled constant skin temperature mode in a climatic chamber. Good agreement was found between the measured and the numerically predicted values of base panel temperature. By integrating the validated heat pipe with a bio-heat model, the back segmental skin temperature as well as the overall thermal comfort was predicted and compared with the conventional seat case without the heat pipe system. The heat pipes were able to reduce the skin temperature by 1 °C and to increase the overall thermal comfort of the body by 30%. In addition, a parametric study was performed to determine the optimal number of heat pipes that ensure the thermal comfort of the passenger.

Thermoregulation and thermal perception in the cold and heat before and after intermittent heat adaptation

Science.gov (United States)

Issing, K.; Fuhr, E.

1986-09-01

Students wearing swim suits were exposed for 30 min to neutral room temperature (TR=28‡C). During the following 60 min they were subjected to gradual decreases or increases of room temperature reaching 12‡C or 45‡C, respectively. Static thermal stimuli were applied to the palms of the right (38‡C) and left (25‡C) hands. Hands and feet of all subjects were thermally isolated at 22‡C ambient temperature. General thermal comfort (GTC), local thermal comfort (LTC), skin blood flow (which is proportional to heat transport index λ) several body temperatures, oxygen-consumption(dot V_{O_2 } ), and sweat rate (S), were measured. After moderate intermittent heat exposures (7 times for 1h at TR=42.5‡C) the experiments started again. From GTC, LTC, or λ as functions of TR, no new knowledge about thermoregulatory or adaptive mechanisms was available. The high λ in the cold stimulated left hand, however, and the oscillatory thresholds (λOSC) for rhythmic vasomotion indicated the peripheral influence of skin temperature, as well as local, mean skin temperature (¯Ts) and core temperature. When exposed to moderate temperature decreases or increases the body seems to react only with increasing thermal resistance by vasoconstriction or an increase of sweat rate, respectively. Moderate heat adaptation is only able to raise sweat rate, but not the thresholds and gain of the S-function. We assume that functional studies of adaptive modifications in humans must be conducted at temperatures greatly beyond those used in these experiments.

Can intradermal administration of angiotensin II influence human heat loss responses during whole body heat stress?

Science.gov (United States)

Fujii, Naoto; Meade, Robert D; Paull, Gabrielle; McGinn, Ryan; Foudil-bey, Imane; Akbari, Pegah; Kenny, Glen P

2015-05-01

It is unclear if angiotensin II, which can increase the production of reactive oxygen species (oxidative stress), modulates heat loss responses of cutaneous blood flow and sweating. We tested the hypothesis that angiotensin II-induced increases in oxidative stress impair cutaneous perfusion and sweating during rest and exercise in the heat. Eleven young (24 ± 4 yr) healthy adults performed two 30-min cycling bouts at a fixed rate of metabolic heat production (400 W) in the heat (35°C). The first and second exercises were followed by a 20- and 40-min recovery. Four microdialysis fibers were placed in the forearm skin for continuous administration of either: 1) lactated Ringer (control), 2) 10 μM angiotensin II, 3) 10 mM ascorbate (an antioxidant), or 4) a combination of 10 μM angiotensin II + 10 mM ascorbate. Cutaneous vascular conductance (CVC; laser-Doppler perfusion units/mean arterial pressure) and sweating (ventilated capsule) were evaluated at each skin site. Compared with control, angiotensin II reduced both CVC and sweating at baseline resting and during each recovery in the heat (all P 0.05). When ascorbate was coinfused with angiotensin II, the effect of angiotensin II on sweating was abolished (all P > 0.05); however, its effect on CVC at baseline resting and during each recovery remained intact (all P stress, while it impairs sweating through increasing oxidative stress during exposure to an ambient heat stress before and following exercise. Copyright © 2015 the American Physiological Society.

A flexible skin piloerection monitoring sensor

Science.gov (United States)

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

2014-06-01

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

Nonlinear convective flow of Powell-Erying magneto nanofluid with Newtonian heating

Directory of Open Access Journals (Sweden)

Sajid Qayyum

Full Text Available Objective of present article is to describe magnetohydrodynamic (MHD non-linear convective flow of Powell-Erying nanofluid over a stretching surface. Characteristics of Newtonian heat and mass conditions in this attempt is given attention. Heat and mass transfer analysis is examined in the frame of thermal radiation and chemical reaction. Brownian motion and thermophoresis concept is introduced due to presence of nanoparticles. Nonlinear equations of momentum, energy and concentration are transformed into dimensionless expression by invoking suitable variables. The series solutions are obtained through homotopy analysis method (HAM. Impact of embedded variables on the velocity, temperature and nanoparticles concentration is graphically presented. Numerical values of skin friction coefficient, local Nusselt and Sherwood numbers are computed and analyzed. It is concluded that velocity field enhances for fluid variable while reverse situation is noticed regarding Hartman number. Temperature and heat transfer rate behave quite reverse for Prandtl number. It is also noted that the concentration and local Sherwood number have opposite behavior in the frame of Brownian motion. Keywords: Powell-Erying nanofluid, Magnetohydrodynamic (MHD, Nonlinear convection, Thermal radiation, Chemical reaction, Newtonian heat and mass conditions

Application of Universal Thermal Climate Index (UTCI) for assessment of occupational heat stress in open-pit mines.

Science.gov (United States)

Nassiri, Parvin; Monazzam, Mohammad Reza; Golbabaei, Farideh; Dehghan, Somayeh Farhang; Rafieepour, Athena; Mortezapour, Ali Reza; Asghari, Mehdi

2017-10-07

The purpose of this article is to examine the applicability of Universal Thermal Climate Index (UTCI) index as an innovative index for evaluating of occupational heat stress in outdoor environments. 175 workers of 12 open-pit mines in Tehran, Iran were selected for this research study. First, the environmental variables such as air temperature, wet-bulb temperature, globe temperature, relative humidity and air flow rate were measured; then UTCI, wet-bulb globe temperature (WBGT) and heat stress index (HSI) indices were calculated. Simultaneously, physiological parameters including heart rate, oral temperature, tympanic temperature and skin temperature of workers were measured. UTCI and WBGT are positively significantly correlated with all environmental parameters (p0.05). Moreover, a strong significant relationship was found between UTCI and WBGT (r=0.95; p<0.001). The significant positive correlations exist between physiological parameters including oral temperature, tympanic and skin temperatures and heart rate and both the UTCI and WBGT indices (p<0.029). The highest correlation coefficient has been found between the UTCI and physiological parameters. Due to the low humidity and air velocity (~<1 m/s) in understudied mines, UTCI index appears to be appropriate to assess the occupational heat stress in these outdoor workplaces.

In Vivo Radiofrequency Heating in Swine in a 3T (123.2 MHz) Birdcage Whole-Body Coil

Science.gov (United States)

Shrivastava, Devashish; Utecht, Lynn; Tian, Jinfeng; Hughes, John; Vaughan, J. Thomas

2014-01-01

Purpose To study in vivo radiofrequency (RF) heating produced due to power deposition from a 3T (Larmour frequency = 123.2 MHz), birdcage, whole-body coil. Methods The RF heating was simulated in a digital swine by solving the mechanistic generic bioheat transfer model (GBHTM) and the conventional, empirical Pennes bioheat transfer equation for the following two cases: (1) when the porcine head was in the isocenter, and (2) when the porcine trunk was in the isocenter. The simulation results were validated by making direct fluoroptic temperature measurements in the skin, brain, simulated hot regions, and rectum of ten swine (Case 1, N= 5, mean animal weight = 84.03 ± 6.85 kg, Whole-body average SAR = 2.65 ± 0.22 W/kg; Case 2, N= 5, mean animal weight = 81.59 ± 6.23 kg, Whole-body average SAR = 2.77 ± 0.26 W/kg) during one hour of exposure to a turbo spin echo sequence. Results The GBHTM simulated the RF heating more accurately compared to the Pennes equation. In vivo temperatures exceeded safe temperature thresholds with allowable SAR exposures. Hot regions may be produced deep inside the body, away from the skin. Conclusion SAR exposures to produce safe temperature thresholds may need re-investigation. PMID:24259413

A novel non-invasive radiofrequency dermal heating device for skin tightening of the face and neck.

Science.gov (United States)

Nelson, Andrew A; Beynet, David; Lask, Gary P

2015-01-01

Loose, lax skin is a common cosmetic complaint. Previous non-invasive skin tightening devices had modest efficacy and were associated with pain or downtime. New technologies may allow for effective skin tightening with a series of radiofrequency (RF) treatments with no downtime. To evaluate the efficacy and safety of a novel bipolar RF device for skin tightening. Fifteen consecutive female patients were enrolled in the case series; 14 completed the study and were included in the analysis. The device under investigation is a novel, bipolar RF device allowing for achievement and maintenance of optimal dermal temperatures to stimulate collagen remodeling and skin tightening. Patients underwent a series of 4-6 weekly treatments. Three blinded, experienced cosmetic physicians evaluated paired pre-treatment and post-treatment photographs and determined the associated improvement, if any. All patients (14/14) were determined to have a clinical improvement, as the pre-treatment and post-treatment photographs were correctly identified by the evaluators. It was observed that 21% (3/14) of patients had significant improvement, 50% (7/14) had moderate improvement, and 29% (4/14) had mild improvement. No pain, side effects, or adverse events were observed. This novel bipolar RF device represents a safe, effective treatment option for non-invasive skin tightening.

Analysis of the passive heat removal enhancement for AP1000 containment due to the partially wetted coverage

Energy Technology Data Exchange (ETDEWEB)

Li, Cheng, E-mail: 510395453@qq.com [State Nuclear Power Technology Research & Development Center, 102209 Beijing (China); Li, Le [Tsinghua University, Institute of Nuclear and New Energy Technology, 100084 Beijing (China); Li, Junming [Tsinghua University, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Beijing 100084 (China); Zhang, Yajun [Tsinghua University, Institute of Nuclear and New Energy Technology, 100084 Beijing (China); Li, Zhihui [State Nuclear Power Technology Research & Development Center, 102209 Beijing (China)

2017-03-15

Highlights: • Heat removal by steam condensation, thermal conduction and evaporation is the most important scheme for AP1000 PCCS. Traditionally, studies on containment wall condensation and evaporation have been widely made, while it lacks studies on the shell two-dimension (2-D) thermal conduction. Currently, based on the known heat and mass transfer correlations and the phenomenon from water wetted coverage test, the physical model for 2-D thermal conduction is given and numerical simulation is then made. By discussions, it forms the following highlights. • The partially wetted surface can enhance the whole heat transfer process (including inner condensation, wall thermal conduction and outside cooling) and the maximum enhancement factor can be as large as 63%. There is an enhancement peak at around dry strip fraction a = 90%. When L is less than 0.03 m, its influence on heat transfer is small and the enhancement is mainly affected by dry coverage. However, for larger L, both α and L contribute much to larger enhancement. • Location at the spring line is often used for safety analysis and the dry strip fraction there for AP1000 is mainly at 10%–80%. Accordingly, further analysis is made on L (0.03 < L < 0.3) and a fitting expression is given for α = 10%–80%. It could be used to improve the corresponding software and it could also be used for containment scaling-down criteria analysis. - Abstract: AP1000 containment uses the water film evaporation, coupled with containment inner condensation, to remove the core decay heat. However, water film cannot fully cover heat transfer surface and dry-wetted strips appear. As a result, heat transfer within the containment shell is a two-dimension thermal conduction. Current work numerically studied the AP1000 heat removal enhancement due to the partially wetted coverage phenomenon. It used the evaporation and condensation boundary conditions and Fluent software to calculate the local heat fluxes and their

Analysis of the passive heat removal enhancement for AP1000 containment due to the partially wetted coverage

International Nuclear Information System (INIS)

Li, Cheng; Li, Le; Li, Junming; Zhang, Yajun; Li, Zhihui

2017-01-01

Highlights: • Heat removal by steam condensation, thermal conduction and evaporation is the most important scheme for AP1000 PCCS. Traditionally, studies on containment wall condensation and evaporation have been widely made, while it lacks studies on the shell two-dimension (2-D) thermal conduction. Currently, based on the known heat and mass transfer correlations and the phenomenon from water wetted coverage test, the physical model for 2-D thermal conduction is given and numerical simulation is then made. By discussions, it forms the following highlights. • The partially wetted surface can enhance the whole heat transfer process (including inner condensation, wall thermal conduction and outside cooling) and the maximum enhancement factor can be as large as 63%. There is an enhancement peak at around dry strip fraction a = 90%. When L is less than 0.03 m, its influence on heat transfer is small and the enhancement is mainly affected by dry coverage. However, for larger L, both α and L contribute much to larger enhancement. • Location at the spring line is often used for safety analysis and the dry strip fraction there for AP1000 is mainly at 10%–80%. Accordingly, further analysis is made on L (0.03 < L < 0.3) and a fitting expression is given for α = 10%–80%. It could be used to improve the corresponding software and it could also be used for containment scaling-down criteria analysis. - Abstract: AP1000 containment uses the water film evaporation, coupled with containment inner condensation, to remove the core decay heat. However, water film cannot fully cover heat transfer surface and dry-wetted strips appear. As a result, heat transfer within the containment shell is a two-dimension thermal conduction. Current work numerically studied the AP1000 heat removal enhancement due to the partially wetted coverage phenomenon. It used the evaporation and condensation boundary conditions and Fluent software to calculate the local heat fluxes and their

Hyperpigmentation of the skin associated with minocycline therapy

International Nuclear Information System (INIS)

Gordon, G.; Sparano, B.M.; Iatropoulos, M.J.

1985-01-01

Skin biopsy specimens and discolored fingernails from minocycline-treated patients were examined by light and electron microscopy, histochemistry, and energy-dispersive x-ray analysis. Both hyperpigmented and adjacent normally pigmented skin samples contained pigment-laden macrophages in the dermis, although these cells were more numerous in the hyperpigmented skin samples. Elemental analysis showed that both pigment deposits and stratum corneum of hyperpigmented skin samples contained iron and calcium. Discolored areas of fingernails from a minocycline-treated patient also contained iron and calcium. Both skin and nail discoloration were possibly due to the presence of an iron chelate of minocycline and/or quinoid derivatives of minocycline. The presence of iron-containing pigment in normal as well as hyperpigmented skin may have predisposed to formation of minocycline-associated pigment in these patients

Effects of cryogen spray cooling and high radiant exposures on selective vascular injury during laser irradiation of human skin.

Science.gov (United States)

Tunnell, James W; Chang, David W; Johnston, Carol; Torres, Jorge H; Patrick, Charles W; Miller, Michael J; Thomsen, Sharon L; Anvari, Bahman

2003-06-01

Increasing radiant exposure offers a means to increase treatment efficacy during laser-mediated treatment of vascular lesions, such as port-wine stains; however, excessive radiant exposure decreases selective vascular injury due to increased heat generation within the epidermis and collateral damage to perivascular collagen. To determine if cryogen spray cooling could be used to maintain selective vascular injury (ie, prevent epidermal and perivascular collagen damage) when using high radiant exposures (16-30 J/cm2). Observational study. Academic hospital and research laboratory. Twenty women with normal abdominal skin (skin phototypes I-VI). Skin was irradiated with a pulsed dye laser (wavelength = 585 nm; pulse duration = 1.5 milliseconds; 5-mm-diameter spot) using various radiant exposures (8-30 J/cm2) without and with cryogen spray cooling (50- to 300-millisecond cryogen spurts). Hematoxylin-eosin-stained histologic sections from each irradiated site were examined for the degree of epidermal damage, maximum depth of red blood cell coagulation, and percentage of vessels containing perivascular collagen coagulation. Long cryogen spurt durations (>200 milliseconds) protected the epidermis in light-skinned individuals (skin phototypes I-IV) at the highest radiant exposure (30 J/cm2); however, epidermal protection could not be achieved in dark-skinned individuals (skin phototypes V-VI) even at the lowest radiant exposure (8 J/cm2). The red blood cell coagulation depth increased with increasing radiant exposure (to >2.5 mm for skin phototypes I-IV and to approximately 1.2 mm for skin phototypes V-VI). In addition, long cryogen spurt durations (>200 milliseconds) prevented perivascular collagen coagulation in all skin types. Cryogen spurt durations much longer than those currently used in therapy (>200 milliseconds) may be clinically useful for protecting the epidermis and perivascular tissues when using high radiant exposures during cutaneous laser therapies

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.

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)

Lithospheric stresses due to radiogenic heating of an ice-silicate planetary body - Implications for Ganymede's tectonic evolution

Science.gov (United States)

Zuber, M. T.; Parmentier, E. M.

1984-01-01

Thermal evolution models of differentiated and undifferentiated ice-silicate bodies containing long-lived radiogenic heat sources are examined. Lithospheric sresses arise due to volume change of the interior and temperature change in the lithosphere. For an undifferentiated body, the surface stress peaks early in the evolution, while in the differentiated case, stresses peak later and continue to accumulate for longer periods of time. The variation of near-surface stress with depth shows that stresses for the undifferentiated body initially penetrate to great depths, but rapidly concentrate within a few kilometers of the surface. For the differentiated body, elastic stresses never accumulate at a depth greater than a few kilometers. These models are applied to consider long-term rdioactive heating as a possible mechanism of tectonic activity and bright terrain formation on Ganymede.

Ectodermal dysplasia-skin fragility syndrome

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Vijay S Adhe

2011-01-01

Full Text Available Ectodermal dysplasia-skin fragility (EDSF syndrome is a rare and first described inherited disorder of desmosomes. It occurs due to loss-of-function mutations in PKP1 gene resulting in poorly formed desmosomes and loss of desmosomal and epidermal integrity. We report a case of a 2-year-old Indian male child who presented with palmoplantar hyperkeratosis with fissuring, short, sparse, and easily pluckable scalp hair, nail dystrophy, and multiple erosions over the skin. Skin biopsy showed epidermal hyperplasia with widening of intercellular spaces. His developmental milestones were delayed but intelligence was normal. Echocardiography, X-ray chest, and electrocardiogram were normal. Very few cases of this syndrome have been reported in the literature. We consider this as the first case report from India.

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.

Clinical picture of delayed radiation effects in the skin

International Nuclear Information System (INIS)

Hundeiker, M.

1987-01-01

Chronic radiation injuries of the skin develop over years or decades. Gradually increasing atrophy, sclerosis, telangiectasis, possibly - in highly exposed parts of the skin - keratosis due to radiation ulcers, carcinomas and basilomas occur after a latency period of decades, not so much in X-ray-injured skin after tumour therapy as in diffusely altered X-ray-injured skin after multiple exposure to low doses. Radiotherapy is indispensable, but like other effective methods of treatment it requires stringent indications, accurate execution and careful after-treatment. (TRV) [de

Skin too thin? The developing utility of zebrafish skin (neuro)pharmacology for CNS drug discovery research.

Science.gov (United States)

Nguyen, Michael; Poudel, Manoj K; Stewart, Adam Michael; Kalueff, Allan V

2013-09-01

Skin coloration can be affected by many genetic, environmental and pharmacological factors. Zebrafish (Danio rerio) are a useful and versatile model organism in biomedical research due to their genetic tractability, physiological homology to mammals, low cost, reproducibility and high throughput. Zebrafish coloration is mediated by chromatophores - the skin color pigment cells largely controlled by endocrine and neural mechanisms. The characteristic darkening of zebrafish skin is caused by the dispersion (and paling - by aggregation) of melanosomes (pigment-containing organelles), which show high homology to mammalian structures. Various pharmacological agents potently affect zebrafish coloration - the phenotype that often accompanies behavioral effects of the drugs, and may be used for drug discovery. Although zebrafish behavior and skin responses are usually not directly related, they share common regulatory (neural, endocrine) mechanisms, and therefore may be assessed in parallel during psychotropic drug screening. For example, some psychoactive drugs can potently affect zebrafish skin coloration. Can we use this knowledge to refine phenotype-driven psychotropic drug discovery? Here, we present current models using zebrafish skin coloration assays, and discuss how these models may be applied to enhance in vivo CNS drug discovery. Copyright © 2013 Elsevier Inc. All rights reserved.

The Use of Matriderm and Autologous Skin Graft in the Treatment of Full Thickness Skin Defects

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Jang Hwan Min

2014-07-01

Full Text Available Background For patients with full thickness skin defects, autologous Split-thickness skin grafts (STSG are generally regarded as the mainstay of treatment. However, skin grafts have some limitations, including undesirable outcomes resulting from scars, poor elasticity, and limitations in joint movement due to contractures. In this study, we present outcomes of Matriderm grafts used for various skin tissue defects whether it improves on these drawbacks. Methods From January 2010 to March 2012, a retrospective review of patients who had undergone autologous STSG with Matriderm was performed. We assessed graft survival to evaluate the effectiveness of Matriderm. We also evaluated skin quality using a Cutometer, Corneometer, Tewameter, or Mexameter, approximately 12 months after surgery. Results A total of 31 patients underwent STSG with Matriderm during the study period. The success rate of skin grafting was 96.7%. The elasticity value of the portion on which Matriderm was applied was 0.765 (range, 0.635-0.800, the value of the trans-epidermal water loss (TEWL was 10.0 (range, 8.15-11.00 g/hr/m2, and the humidification value was 24.0 (range, 15.5-30.0. The levels of erythema and melanin were 352.0 arbitrary unit (AU (range, 299.25-402.75 AU and 211.0 AU (range, 158.25-297.00 AU, respectively. When comparing the values of elasticity and TEWL of the skin treated with Matriderm to the values of the surrounding skin, there was no statistically significant difference between the groups. Conclusions The results of this study demonstrate that a dermal substitute (Matriderm with STSG was adopted stably and with minimal complications. Furthermore, comparing Matriderm grafted skin to normal skin using Cutometer, Matriderm proved valuable in restoring skin elasticity and the skin barrier.

Fabrication of Non-Implant 3D Printed Skin

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Chuan Yong Leng

2018-01-01

Full Text Available Many bandages tend to be harmful when being removed from the human skin. This is a crucial issue, especially faced by burn victims. When bandages are removed from the burn wound, they tend to be harmful by peeling off the newly formed layer of skin over the burn wound. Such nature causes the patient to endure a longer recovery time with additional pain. The objective of this project is to 3D print artificial skin for the victims of burn wounds by using natural gelation. The main aim for creating the artificial skin will be used in place of the current burn wound treatment techniques of dressing the wounds in bandages. The inner layer of this skin was lined with a natural adhesive, a thin layer of agar-agar, which has been reinforced with crushed eggshells to increase its adhesive strength and durability. The synthesized gel contained non adhesive behavior, yet aids in wound healing abilities. Applying hydrocolloids ensures that the wound is kept cool and the gel also ensures efficient heat transfer. This was done so that less sweating occurs on the patient. Based on the experiments that were conducted, the results conclude that the best ratio of artificial skin layer would be 2:1 of agar gel: crushed eggshells. This golden ratio of gel: crushed eggshells for the longest period of time for attachment on the skin without sweating, is achieved. The skin will be printed using Acrylonitrile-Butadiene-Styrene (ABS. The colour of the skin and the shape of the skin was individually designed for each specific patient. The inner gel has the capabilities of reducing the rehabilitation time, without compromising the comfort of the patient. This approach has the potential to be used as a new method to treat burn wounds..

Skin dose assessment in routine personnel beta/gamma dosimetry

International Nuclear Information System (INIS)

Christensen, P.

1980-01-01

Three alternative methods are outlined by which substantial improvements of the capabilities of existing routine monitoring systems for skin dose assessment can be obtained. The introduction of a supplementary skin dosemeter may be an attractive method for systems with badges that have a capability for an additional dosemeter already built-in. The two-side reading method has limited possibilities because of reduced accuracy for mixed radiation and technical difficulties in using it for TLD systems with planchet heating. The use of a boron diffused LiF layer for skin dose assessment seems to be most attractive method since the only modification needed here is replacement of a dosemeter. However the study of this method is so far only in a preliminary stage and further investigations are needed. (U.K.)

Random regression models to account for the effect of genotype by environment interaction due to heat stress on the milk yield of Holstein cows under tropical conditions.

Science.gov (United States)

Santana, Mário L; Bignardi, Annaiza Braga; Pereira, Rodrigo Junqueira; Menéndez-Buxadera, Alberto; El Faro, Lenira

2016-02-01

The present study had the following objectives: to compare random regression models (RRM) considering the time-dependent (days in milk, DIM) and/or temperature × humidity-dependent (THI) covariate for genetic evaluation; to identify the effect of genotype by environment interaction (G×E) due to heat stress on milk yield; and to quantify the loss of milk yield due to heat stress across lactation of cows under tropical conditions. A total of 937,771 test-day records from 3603 first lactations of Brazilian Holstein cows obtained between 2007 and 2013 were analyzed. An important reduction in milk yield due to heat stress was observed for THI values above 66 (-0.23 kg/day/THI). Three phases of milk yield loss were identified during lactation, the most damaging one at the end of lactation (-0.27 kg/day/THI). Using the most complex RRM, the additive genetic variance could be altered simultaneously as a function of both DIM and THI values. This model could be recommended for the genetic evaluation taking into account the effect of G×E. The response to selection in the comfort zone (THI ≤ 66) is expected to be higher than that obtained in the heat stress zone (THI > 66) of the animals. The genetic correlations between milk yield in the comfort and heat stress zones were less than unity at opposite extremes of the environmental gradient. Thus, the best animals for milk yield in the comfort zone are not necessarily the best in the zone of heat stress and, therefore, G×E due to heat stress should not be neglected in the genetic evaluation.

Biologic and synthetic skin substitutes: An overview.

Science.gov (United States)

Halim, Ahmad Sukari; Khoo, Teng Lye; Mohd Yussof, Shah Jumaat

2010-09-01

The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. Skin substitutes have important roles in the treatment of deep dermal and full thickness wounds of various aetiologies. At present, there is no ideal substitute in the market. Skin substitutes can be divided into two main classes, namely, biological and synthetic substitutes. The biological skin substitutes have a more intact extracellular matrix structure, while the synthetic skin substitutes can be synthesised on demand and can be modulated for specific purposes. Each class has its advantages and disadvantages. The biological skin substitutes may allow the construction of a more natural new dermis and allow excellent re-epithelialisation characteristics due to the presence of a basement membrane. Synthetic skin substitutes demonstrate the advantages of increase control over scaffold composition. The ultimate goal is to achieve an ideal skin substitute that provides an effective and scar-free wound healing.

Biologic and synthetic skin substitutes: An overview

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Halim Ahmad

2010-10-01

Full Text Available The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. Skin substitutes have important roles in the treatment of deep dermal and full thickness wounds of various aetiologies. At present, there is no ideal substitute in the market. Skin substitutes can be divided into two main classes, namely, biological and synthetic substitutes. The biological skin substitutes have a more intact extracellular matrix structure, while the synthetic skin substitutes can be synthesised on demand and can be modulated for specific purposes. Each class has its advantages and disadvantages. The biological skin substitutes may allow the construction of a more natural new dermis and allow excellent re-epithelialisation characteristics due to the presence of a basement membrane. Synthetic skin substitutes demonstrate the advantages of increase control over scaffold composition. The ultimate goal is to achieve an ideal skin substitute that provides an effective and scar-free wound healing.

Estimation of shutdown heat generation rates in GHARR-1 due to ...

African Journals Online (AJOL)

Fission products decay power and residual fission power generated after shutdown of Ghana Research Reactor-1 (GHARR-1) by reactivity insertion accident were estimated by solution of the decay and residual heat equations. A Matlab program code was developed to simulate the heat generation rates by fission product ...

Effects of menthol application on the skin during prolonged immersion in cool and cold water.

Science.gov (United States)

Botonis, P G; Kounalakis, S N; Cherouveim, E D; Koskolou, M D; Geladas, N D

2018-03-01

The aim of the study was to compare the effect of skin surface menthol application on rectal temperature (Tre) during prolonged immersion in cool and cold water. We hypothesized that menthol application would lead to a slower Tre decline due to the reduced heat loss as a consequence of the menthol-induced vasoconstriction and that this effect would be attenuated during cold-water immersion. Six male subjects were immersed for 55 minutes in stirred cool (24°C) or cold (14°C) water immediately after attaining a Tre of 38°C by cycling at 60% of maximum heart rate on two occasions: without (ΝM) and with (M) whole-body skin application of menthol cream. Tre, the proximal-distal skin temperature gradient, and oxygen uptake were continuously measured. ANOVA with repeated measures was employed to detect differences among variables. Significance level was set at 0.05. The area under the curve for Tre was calculated and was greater in 24°C M (-1.81 ± 8.22 a.u) compared to 24°C NM (-27.09 ± 19.09 a.u., P = .03, r = .90), 14°C NM (-18.08 ± 10.85 a.u., P = .03, r = .90), and 14°C M (-11.71 ± 12.58 a.u, P = .05, r = .81). In cool water, oxygen uptake and local vasoconstriction were increased (P ≤ .05) by 39 ± 25% and 56 ± 37%, respectively, with menthol compared to ΝM, while no differences were observed in cold water. Menthol application on the skin before prolonged immersion reduces heat loss resulting in a blunted Tre decline. However, such a response is less obvious at 14°C water immersion, possibly because high-threshold cold-sensitive fibers are already maximally recruited and the majority of cold receptors saturated. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Digital dermoscopy to determine skin melanin index as an objective indicator of skin pigmentation

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Sara Majewski

2016-04-01

Full Text Available Clinical assessment of skin photosensitivity is subjectively determined by erythema and tanning responses to sunlight recalled by the subject, alternatively known as Fitzpatrick Skin Phototype (SPT. Responses may be unreliable due to recall bias, subjective bias by clinicians and subjects, and lack of cultural sensitivity of the questions. Analysis of red-green-blue (RGB color spacing of digital images may provide an objective determination of SPT. This paper presents the studies to assess the melanin index (MI, as determined by RGB images obtained by both standard digital camera as well as by videodermoscope, and to correlate the MI with SPT based upon subjects’ verbal responses to standardized questions administered by a dermatologist.A sample of subjects representing all SPTs I–VI was selected. Both the digital camera and videodermoscope were calibrated at standard illumination, light source and white balance. Images of constitutive skin of the upper ventral arm were taken of each subject using both instruments.The studies showed that 58 subjects (20 M, 38 F were enrolled in the study (mean age: 47 years; range: 20–89, stratified to skin phototype I–VI. MI obtained by using both digital camera and videodermoscope increased significantly as the SPT increased p = 0.004 and p < 0.0001, respectively and positively correlated with dermatologist-assessed SPT (Spearman correlation, r = 0.48 and r = 0.84, respectively.Digital imaging can quantify melanin content in order to quantitatively approximate skin pigmentation in all skin phototypes including Type VI skin. This methodology holds promise as a simple, non-invasive, rapid and objective approach to reliably determine skin phototype and, with further investigation, may prove to be both practical and useful in the prediction of skin cancer risk.

Polycomponent mesotherapy formulations for the treatment of skin aging and improvement of skin quality

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Prikhnenko S

2015-04-01

Full Text Available Sergey Prikhnenko Private Practice, Novosibirsk, Russia Abstract: Skin aging can largely be attributed to dermal fibroblast dysfunction and a decrease in their biosynthetic activity. Regardless of the underlying causes, aging fibroblasts begin to produce elements of the extracellular matrix in amounts that are insufficient to maintain the youthful appearance of skin. The goal of mesopreparations is primarily to slow down and correct changes in skin due to aging. The rationale for developing complex polycomponent mesopreparations is based on the principle that aging skin needs to be supplied with the various substrates that are key to the adequate functioning of the fibroblast. The quintessential example of a polycomponent formulation – NCTF® (New Cellular Treatment Factor – includes vitamins, minerals, amino acids, nucleotides, coenzymes and antioxidants, as well as hyaluronic acid, designed to help fibroblasts function more efficiently by providing a more optimal environment for biochemical processes and energy generation, as well as resisting the effects of oxidative stress. In vitro experiments suggest that there is a significant increase in the synthetic and prophylactic activity of fibroblasts with treated NCTF, and a significant increase in the ability of cells to resist oxidative stress. The current article looks at the rationale behind the development of polycomponent mesopreparations, using NCTF as an example. Keywords: mesotherapy, skin aging, skin quality

Let the sun shine in: mechanisms and potential for therapeutics in skin photodamage.

Science.gov (United States)

Wondrak, Georg T

2007-05-01

Photoaging and photocarcinogenesis are the two Janus faces of skin photodamage. Reactivity-based design of prototype agents that antagonize, modulate and reverse the chemistry of skin photodamage holds promise in delivering unprecedented therapeutic benefit. In contrast to structure-based approaches that use selective ligands to target macromolecules, reactivity-based drug discovery uses chemical reagents as therapeutics to target reactive chemical species as key mediators of skin photo-oxidative stress. The following classes of reactivity-based agents for skin photoprotection can be distinguished based on their mechanism of action: direct antagonists of photo-oxidative stress (sunscreens, quenchers of photo-excited states, antioxidants, redox modulators and glycation inhibitors) and skin photo-adaptation inducers (nuclear factor erythroid 2-related factor 2 [Nrf2] activators, heat-shock response inducers and metallothionein inducers).

MINIVER: Miniature version of real/ideal gas aero-heating and ablation computer program

Science.gov (United States)

Hendler, D. R.

1976-01-01

Computer code is used to determine heat transfer multiplication factors, special flow field simulation techniques, different heat transfer methods, different transition criteria, crossflow simulation, and more efficient thin skin thickness optimization procedure.

Analysis of temperature profile and electric field in natural rubber glove due to microwave heating: effects of waveguide position

Science.gov (United States)

Keangin, P.; Narumitbowonkul, U.; Rattanadecho, P.

2018-01-01

Natural rubber (NR) is the key raw material used in the manufacture of other products such as rubber band, tire and shoes. Recently, the NR is used in natural rubber glove ( NRG) manufacturing in the industrial and medical fields. This research aims to investigate the electromagnetic wave propagation and heat transfer in NRG due to heating with microwave energy within the microwave oven at a microwave frequency of 2.45 GHz. Three-dimensional model of NRG and microwave oven are considered in this work. The comparative effects of waveguide position on the electric field and temperature profile in NRG when subjected to microwave energy are discussed. The finite element method (FEM) is used to solve the transient Maxwell’s equation coupled with the transient heat transfer equation. The simulation results with computer programs are validated with experimental results. The placement of waveguides in three cases are left hand side of microwave oven, right hand side of microwave oven and left and right hand sides of microwave oven are investigated. The findings revealed that the placing the waveguide on the right side of the microwave oven gives the highest electric field and temperature profile. The values obtained provide an indication toward understanding the study of heat transfer in NRG during microwave heating in the industry.

Marangoni convection in Casson liquid flow due to an infinite disk with exponential space dependent heat source and cross-diffusion effects

Science.gov (United States)

Mahanthesh, B.; Gireesha, B. J.; Shashikumar, N. S.; Hayat, T.; Alsaedi, A.

2018-06-01

Present work aims to investigate the features of the exponential space dependent heat source (ESHS) and cross-diffusion effects in Marangoni convective heat mass transfer flow due to an infinite disk. Flow analysis is comprised with magnetohydrodynamics (MHD). The effects of Joule heating, viscous dissipation and solar radiation are also utilized. The thermal and solute field on the disk surface varies in a quadratic manner. The ordinary differential equations have been obtained by utilizing Von Kármán transformations. The resulting problem under consideration is solved numerically via Runge-Kutta-Fehlberg based shooting scheme. The effects of involved pertinent flow parameters are explored by graphical illustrations. Results point out that the ESHS effect dominates thermal dependent heat source effect on thermal boundary layer growth. The concentration and temperature distributions and their associated layer thicknesses are enhanced by Marangoni effect.

Reduction of birefringence in a skin-layer of injection molded polymer strips using CO{sub 2} laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Kurosaki, Yasuo; Satoh, Isao; Saito, Takushi [Tokyo Inst. of Tech. (Japan). Dept. of Mechanical Intelligent Systems Engineering

1995-12-31

Injection molding of polymers is currently utilized for numerous industrial applications. Because of high productivity and stable quality of molded products, the injection-molding process makes the production costs lower, and therefore, is expected to spread more widely in the future. This paper deals with a technique for improving the optical quality of injection molded polymer products using radiative heating. The birefringence frozen in a skin-layer of the molded part was reduced by CO{sub 2} laser heating, and the efficiency of this technique was investigated experimentally. Namely, a simple numerical calculation was performed to estimate the heating efficiency of CO{sub 2} laser in the polymer, effects of radiation heating on the skin-layer of the molded polymer were observed by using a mold with transparent windows, and the residual birefringence frozen in the final molded specimen was measured. The results clearly showed that the birefringence in the skin-layer of injection molded polymer strips was reduced with CO{sub 2} laser heating. The authors believe that the proposed method for reducing the birefringence frozen in injection-molded polymer products is suitable for practical molding, because process time required for the injection-molding is only slightly increased with this method.

XML Survey of the productivity loss due to heat stress in different tasks of farmers in Darreh Shahr city

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M. R. Monazzam Esmaielpou

2015-09-01

Full Text Available Introduction: Heat is one of the hazardous physical agents in the workplace. Exposure to heat and consequent thermal stress influence workers productivity in addition to adverse health effects. The aim of this study was to determine the heat stress induced productivity loss related to different tasks of farmers in Darreh Shahr city, during summer. Material and Method: This cross-sectional study was conducted in summer, 2014, among farmers in Darreh Shahr city. After determining the sample size, farmers’ activities were determined using hierarchical task analysis (HTA, and WBGT measurements were done according to the ISO7243. Metabolism was estimated by the ISO8996. Following, the type of activities were identified according their required metabolism. Knowing WBGT and workload and using the work capacity model, the productivity loss in different tasks and ultimately total productivity loss were calculated. Result: The mean WBGT activities for plowing, terracing, planting seeds, watering, fertilizing, weeding, spraying, and harvesting were 29.98 °C, 31.28 °C,30.66 °C,31.39 °C,31.99 °C,31.75 °C,31.08 °C, and 30.3 °C, respectively. WBGT values were higher than the permissible level provided by ISO7243 in all farming activities. Maximum value of WBGT was belonged to fertilizing activity (31.99 °C and the lowest value was for plowing (29.98 °C. ANOVA test results did not show a significant difference in WBGT at head, waist, and ankle height. The highest and lowest amount of productivity loss was estimated respectively for weeding and plowing activities. The total productivity loss for farming was calculated 69.3 percent in an hour which is due to high physical activity, working outdoor, with exposure to direct solar radiation, and consequent heat stress imposed to workers. Conclusion: Productivity is a factor which is affected by the workplace heat stress. According to results of the present research, the amount of productivity is reduced

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

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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.

[Data mining analysis of professor Li Fa-zhi AIDS itchy skin medical record].

Science.gov (United States)

Wang, Dan-Ni; Li, Zhen; Xu, Li-Ran; Guo, Hui-Jun

2013-08-01

Analysis of professor Li Fa-zhi in the treatment of AIDS drug laws of itchy skin, provide the corresponding drug reference basis for Chinese medicine treatment of AIDS, skin itching. By using the method of analyzing the complex network of Weishi county, Henan in 2007 October to 2011 July during an interview with professor Li Fa-zhi treatment of AIDS patients with skin pruritus, etiology and pathogenesis analysis, skin itching AIDS syndrome differentiation of old Chinese medicine treatment and medication rule. The use of multi-dimensional query analysis, core drug skin itching AIDS treatment in this study as a windbreak, cicada slough, bupleurum, Qufeng solution table drug, licorice detoxification efficacy of drugs, Radix Scutellariae, Kochia scoparia, clearing away heat and promoting diuresis medicine; core prescription for Jingfang San streak virus. Professor Li Fa-zhi treatment of AIDS in the skin itching Qufeng solution table dehumidification antipruritic treatment.

Heat-transfer dynamics during cryogen spray cooling of substrate at different initial temperatures

International Nuclear Information System (INIS)

Jia Wangcun; Aguilar, Guillermo; Wang Guoxiang; Nelson, J Stuart

2004-01-01

Cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatologic therapy. However, the dominant mechanisms of heat transfer during the transient cooling process are incompletely understood. The objective of this study is to elucidate the physics of CSC by measuring the effect of initial substrate temperature (T 0 ) on cooling dynamics. Cryogen was delivered by a straight-tube nozzle onto a skin phantom. A fast-response thermocouple was used to record the phantom temperature changes before, during and after the cryogen spray. Surface heat fluxes (q'') and heat-transfer coefficients (h) were computed using an inverse heat conduction algorithm. The maximum surface heat flux (q'' max ) was observed to increase with T 0 . The surface temperature corresponding to q'' max also increased with T 0 but the latter has no significant effect on h. It is concluded that heat transfer between the cryogen spray and skin phantom remains in the nucleate boiling region even if T 0 is 80 0 C

Low power radiofrequency electromagnetic radiation for the treatment of pain due to osteoarthritis of the knee

OpenAIRE

U. Santosuosso; M. Maresca; E. Beneforti; L. Alcidi; M. Zoppi

2011-01-01

Different techniques have been used in some rheumatic diseases to induce a therapeutic effect by heating deep tissues. These techniques are commonly known as ‘thermotherapy’ (1-4). It should be observed that adequate heating of deep tissues cannot be obtained by conduction or convection of heat because the skin and subcutaneous fat are good thermal insulators and because heating is reduced by blood flow in superficial vessels. Heating of deep tissues can instead be obtained by conversion of o...

Can Aerosol Offset Urban Heat Island Effect?

Science.gov (United States)

Jin, M. S.; Shepherd, J. M.

2009-12-01

The Urban Heat Island effect (UHI) refers to urban skin or air temperature exceeding the temperatures in surrounding non-urban regions. In a warming climate, the UHI may intensify extreme heat waves and consequently cause significant health and energy problems. Aerosols reduce surface insolation via the direct effect, namely, scattering and absorbing sunlight in the atmosphere. Combining the National Aeronautics and Space Administration (NASA) AERONET (AErosol RObotic NETwork) observations over large cities together with Weather Research and Forecasting Model (WRF) simulations, we find that the aerosol direct reduction of surface insolation range from 40-100 Wm-2, depending on seasonality and aerosol loads. As a result, surface skin temperature can be reduced by 1-2C while 2-m surface air temperature by 0.5-1C. This study suggests that the aerosol direct effect is a competing mechanism for the urban heat island effect (UHI). More importantly, both aerosol and urban land cover effects must be adequately represented in meteorological and climate modeling systems in order to properly characterize urban surface energy budgets and UHI.

Changes In The Heating Degree-days In Norway Due Toglobal Warming

Science.gov (United States)

Skaugen, T. E.; Tveito, O. E.; Hanssen-Bauer, I.

A continuous spatial representation of temperature improves the possibility topro- duce maps of temperature-dependent variables. A temperature scenario for the period 2021-2050 is obtained for Norway from the Max-Planck-Institute? AOGCM, GSDIO ECHAM4/OPEC 3. This is done by an ?empirical downscaling method? which in- volves the use of empirical links between large-scale fields and local variables to de- duce estimates of the local variables. The analysis is obtained at forty-six sites in Norway. Spatial representation of the anomalies of temperature in the scenario period compared to the normal period (1961-1990) is obtained with the use of spatial interpo- lation in a GIS. The temperature scenario indicates that we will have a warmer climate in Norway in the future, especially during the winter season. The heating degree-days (HDD) is defined as the accumulated Celsius degrees be- tween the daily mean temperature and a threshold temperature. For Scandinavian countries, this threshold temperature is 17 Celsius degrees. The HDD is found to be a good estimate of accumulated cold. It is therefore a useful index for heating energy consumption within the heating season, and thus to power production planning. As a consequence of the increasing temperatures, the length of the heating season and the HDD within this season will decrease in Norway in the future. The calculations of the heating season and the HDD is estimated at grid level with the use of a GIS. The spatial representation of the heating season and the HDD can then easily be plotted. Local information of the variables being analysed can be withdrawn from the spatial grid in a GIS. The variable is prepared for further spatial analysis. It may also be used as an input to decision making systems.

Anaphylaxis due to caffeine

OpenAIRE

Sugiyama, Kumiya; Cho, Tatsurai; Tatewaki, Masamitsu; Onishi, Shogo; Yokoyama, Tatsuya; Yoshida, Naruo; Fujimatsu, Takayoshi; Hirata, Hirokuni; Fukuda, Takeshi; Fukushima, Yasutsugu

2015-01-01

We report a rare case of anaphylaxis due to caffeine intake. A 27-year-old woman suffered her first episode of anaphylaxis and a positive skin prick test suggested that the anaphylaxis was due to an IgE-mediated hypersensitivity reaction to caffeine. She was diagnosed with caffeine allergy and has not had an allergic reaction after avoiding foods and drinks containing caffeine. Although caffeine is known to have antiallergic effects, this case shows that caffeine can be an allergen and cause ...

Heat dissipation during hovering and forward flight in hummingbirds.

Science.gov (United States)

Powers, Donald R; Tobalske, Bret W; Wilson, J Keaton; Woods, H Arthur; Corder, Keely R

2015-12-01

Flying animals generate large amounts of heat, which must be dissipated to avoid overheating. In birds, heat dissipation is complicated by feathers, which cover most body surfaces and retard heat loss. To understand how birds manage heat budgets during flight, it is critical to know how heat moves from the skin to the external environment. Hummingbirds are instructive because they fly at speeds from 0 to more than 12 m s(-1), during which they transit from radiative to convective heat loss. We used infrared thermography and particle image velocimetry to test the effects of flight speed on heat loss from specific body regions in flying calliope hummingbirds (Selasphorus calliope). We measured heat flux in a carcass with and without plumage to test the effectiveness of the insulation layer. In flying hummingbirds, the highest thermal gradients occurred in key heat dissipation areas (HDAs) around the eyes, axial region and feet. Eye and axial surface temperatures were 8°C or more above air temperature, and remained relatively constant across speeds suggesting physiological regulation of skin surface temperature. During hovering, birds dangled their feet, which enhanced radiative heat loss. In addition, during hovering, near-body induced airflows from the wings were low except around the feet (approx. 2.5 m s(-1)), which probably enhanced convective heat loss. Axial HDA and maximum surface temperature exhibited a shallow U-shaped pattern across speeds, revealing a localized relationship with power production in flight in the HDA closest to the primary flight muscles. We conclude that hummingbirds actively alter routes of heat dissipation as a function of flight speed.

Doubly stratified MHD tangent hyperbolic nanofluid flow due to permeable stretched cylinder

Science.gov (United States)

Nagendramma, V.; Leelarathnam, A.; Raju, C. S. K.; Shehzad, S. A.; Hussain, T.

2018-06-01

An investigation is exhibited to analyze the presence of heat source and sink in doubly stratified MHD incompressible tangent hyperbolic fluid due to stretching of cylinder embedded in porous space under nanoparticles. To develop the mathematical model of tangent hyperbolic nanofluid, movement of Brownian and thermophoretic are accounted. The established equations of continuity, momentum, thermal and solutal boundary layers are reassembled into sets of non-linear expressions. These assembled expressions are executed with the help of Runge-Kutta scheme with MATLAB. The impacts of sundry parameters are illustrated graphically and the engineering interest physical quantities like skin friction, Nusselt and Sherwood number are examined by computing numerical values. It is clear that the power-law index parameter and curvature parameter shows favorable effect on momentum boundary layer thickness whereas Weissennberg number reveals inimical influence.

Natural Oils for Skin-Barrier Repair: Ancient Compounds Now Backed by Modern Science.

Science.gov (United States)

Vaughn, Alexandra R; Clark, Ashley K; Sivamani, Raja K; Shi, Vivian Y

2018-02-01

Natural plant oils are commonly used as topical therapy worldwide. They are usually easily accessible and are relatively inexpensive options for skin care. Many natural oils possess specific compounds with antimicrobial, antioxidant, anti-inflammatory, and anti-itch properties, making them attractive alternative and complementary treatments for xerotic and inflammatory dermatoses associated with skin-barrier disruption. Unique characteristics of various oils are important when considering their use for topical skin care. Differing ratios of essential fatty acids are major determinants of the barrier repair benefits of natural oils. Oils with a higher linoleic acid to oleic acid ratio have better barrier repair potential, whereas oils with higher amounts of irritating oleic acid may be detrimental to skin-barrier function. Various extraction methods for oils exist, including cold pressing to make unrefined oils, heat and chemical distillation to make essential oils, and the addition of various chemicals to simulate a specific scent to make fragranced oils. The method of oil processing and refinement is an important component of selecting oil for skin care, and cold pressing is the preferred method of oil extraction as the heat- and chemical-free process preserves beneficial lipids and limits irritating byproducts. This review summarizes evidence on utility of natural plant-based oils in dermatology, particularly in repairing the natural skin-barrier function, with the focus on natural oils, including Olea europaea (olive oil), Helianthus annus (sunflower seed oil), Cocos nucifera (coconut oil), Simmondsia chinesis (jojoba oil), Avena sativa (oat oil), and Argania spinosa (argan oil).

Cattaneo-Christov double-diffusion theory for three-dimensional flow of viscoelastic nanofluid with the effect of heat generation/absorption

Science.gov (United States)

Hayat, Tasawar; Qayyum, Sajid; Shehzad, Sabir Ali; Alsaedi, Ahmed

2018-03-01

The present research article focuses on three-dimensional flow of viscoelastic(second grade) nanofluid in the presence of Cattaneo-Christov double-diffusion theory. Flow caused is due to stretching sheet. Characteristics of heat transfer are interpreted by considering the heat generation/absorption. Nanofluid theory comprises of Brownian motion and thermophoresis. Cattaneo-Christov double-diffusion theory is introduced in the energy and concentration expressions. Such diffusions are developed as a part of formulating the thermal and solutal relaxation times framework. Suitable variables are implemented for the conversion of partial differential systems into a sets of ordinary differential equations. The transformed expressions have been explored through homotopic algorithm. Behavior of sundry variables on the velocities, temperature and concentration are scrutinized graphically. Numerical values of skin friction coefficients are also calculated and examined. Here thermal field enhances for heat generation parameter while reverse situation is noticed for heat absorption parameter.

Modeling heat loss from the udder of a dairy cow.

Science.gov (United States)

Gebremedhin, Kifle G; Wu, Binxin

2016-07-01

A mechanistic model that predicts sensible and latent heat fluxes from the udder of a dairy cow was developed. The prediction of the model was spot validated against measured data from the literature, and the result agreed within 7% of the measured value for the same ambient temperature. A dairy cow can lose a significant amount of heat (388W/m(2)) from the udder. This suggests that the udder could be considered as a heat sink. The temperature profile through the udder tissue (core to skin) approached the core temperature for an air temperature ≥37°C whereas the profile decreased linearly from the core to skin surface for an air temperature less than 37°C. Sensible heat loss was dominant when ambient air temperature was less than 37.5°C but latent heat loss was greater than sensible heat loss when air temperature was ≥37.5°C. The udder could lose a total (sensible + latent) heat flux of 338W/m(2) at an ambient temperature of 35°C and blood-flow rate of 3.2×10(-3)m(3)/(sm(3) tissue). The results of this study suggests that, in time of heat stress, a dairy cow could be cooled by cooling the udder only (e.g., using an evaporative cooling jacket). Copyright © 2016 Elsevier Ltd. All rights reserved.

Defense against dermal exposures is only skin deep

DEFF Research Database (Denmark)

Nielsen, Jesper Bo; Nielsen, Flemming; Sørensen, Jens Ahm

2007-01-01

study demonstrates that a limited damage to the skin significantly increases the permeability coefficient (K (p)) as well as total percutaneous penetration of chemicals, and most significantly for those compounds that due to their physicochemical characteristics (the most hydrophilic as well as the most...... compartments is affected by the physicochemical characteristics of the chemicals as well as by the integrity of the skin. This observation may have implications when evaluating the possibility of removing chemicals from the skin through different cleansing procedures following unintended dermal exposures....

Unsteady Hydromagnetic Flow of Radiating Fluid Past a Convectively Heated Vertical Plate with the Navier Slip

Directory of Open Access Journals (Sweden)

O. D. Makinde

2014-01-01

Full Text Available This paper investigates the unsteady hydromagnetic-free convection of an incompressible electrical conducting Boussinesq’s radiating fluid past a moving vertical plate in an optically thin environment with the Navier slip, viscous dissipation, and Ohmic and Newtonian heating. The nonlinear partial differential equations governing the transient problem are obtained and tackled numerically using a semidiscretization finite difference method coupled with Runge-Kutta Fehlberg integration technique. Numerical data for the local skin friction coefficient and the Nusselt number have been tabulated for various values of parametric conditions. Graphical results for the fluid velocity, temperature, skin friction, and the Nusselt number are presented and discussed. The results indicate that the skin friction coefficient decreases while the heat transfer rate at the plate surface increases as the slip parameter and Newtonian heating increase.

Unscheduled DNA synthesis in human skin after in vitro ultraviolet-excimer laser ablation

International Nuclear Information System (INIS)

Green, H.A.; Margolis, R.; Boll, J.; Kochevar, I.E.; Parrish, J.A.; Oseroff, A.R.

1987-01-01

DNA damage repaired by the excision repair system and measured as unscheduled DNA synthesis (UDS) was assessed in freshly excised human skin after 193 and 248 nm ultraviolet (UV)-excimer laser ablative incisions. Laser irradiation at 248 nm induced DNA damage throughout a zone of cells surrounding the ablated and heat-damaged area. In contrast, with 193 nm irradiation UDS was not detected in cells adjacent to the ablated area, even though DNA strongly absorbs this wavelength. Our results suggest that the lack of UDS after 193 nm irradiation is due to: ''shielding'' of DNA by the cellular interstitium, membrane, and cytoplasm, DNA damage that is not repaired by excision repair, or thermal effects that either temporarily or permanently inhibit the excision repair processes

Acute skin lesions due to localized ''hot particle'' radiation exposures

International Nuclear Information System (INIS)

Baum, J.W.; Carsten, A.L.; Kaurin, D.G.L.; Schaefer, C.W.

1996-01-01

Purpose of the studies was to determine incidence and severity of lesions resulting from localized deposition of dose to the skin from small ( 2 at 70μm depth) from isotopes having max beta particle energies from about 0.3-3 MeV. Incidence of erythema and scabs (indicating ulceration) were scored routinely for up to 71 days post-irradiation. Responses followed normal probability distributions, and thus, no true threshold could be defined. Ten and 50% incidence rates were deduced using probit analyses. Lowest dose producing 10% incidence was about 1 Gy for exposures to Yb-175 (0.5 MeV max energy) beta particles. Severity of lesions was estimated using diameters and persistence. From preliminary considerations of probability of induction, size, and persistence of acute lesions, a special limit for hot particle exposures in the range of 5-50 Gy may be reasonable, with an action level between about 1 Gy and the limit

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-04-15

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

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Skin design studies for variable camber morphing airfoils

International Nuclear Information System (INIS)

Gandhi, Farhan; Anusonti-Inthra, Phuriwat

2008-01-01

This paper identifies the desirable attributes of a flexible skin of a morphing wing. The study is conducted using airfoil camber morphing as an example. The ideal flex-skin would be highly anisotropic, having a low in-plane axial stiffness but a high out-of-plane flexural stiffness. Reduced skin axial stiffness allows morphing at low actuation cost. However, for some substructure and actuation designs, a lower limit on the skin's in-plane axial stiffness may be required to prevent unacceptable global camber deformation under aerodynamic loads. High flexural stiffness prevents local deformation of skin sections between supports due to aerodynamic pressure loads, and avoids buckling of skin sections under compression as the airfoil cambers under actuation force. For the camber morphing application the strain levels in the flex-skin are not expected to exceed around 2%. If the axial stiffness of the flex-skin is reduced significantly, it may be necessary to consider aerodynamic stiffness (negligible vis-à-vis structural stiffness for classical airfoils) to accurately calculate deformation under loading. The approach followed in the study can be used to identify specifications for the skin and then reverse engineer and design highly anisotropic composite skins that meet the specifications

Red tattoos, ultraviolet radiation and skin cancer in mice

DEFF Research Database (Denmark)

Lerche, Catharina M.; Heerfordt, Ida M.; Serup, Jørgen

2017-01-01

Ultraviolet radiation (UVR) induces skin cancer. The combination of UVR and red tattoos may be associated with increased risk of skin cancer due to potential carcinogens in tattoo inks. This combination has not been studied previously. Immunocompetent C3.Cg/TifBomTac hairless mice (n=99) were...

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 analysis of heat removal during cryogen spray cooling and effects of simultaneous airflow application.

Science.gov (United States)

Torres, J H; Tunnell, J W; Pikkula, B M; Anvari, B

2001-01-01

Cryogen spray cooling (CSC) is a method used to protect the epidermis from non-specific thermal injury that may occur as a result of various dermatological laser procedures. However, better understanding of cryogen deposition and skin thermal response to CSC is needed to optimize the technique. Temperature measurements and video imaging were carried out on an epoxy phantom as well as human skin during CSC with and without simultaneous application of airflow which was intended to accelerate cryogen evaporation from the substrate surface. An inverse thermal conduction model was used to estimate heat flux and total heat removed. Lifetime of the cryogen film deposited on the surface of skin and epoxy phantom lasted several hundred milliseconds beyond the spurt, but could be reduced to the spurt duration by application of airflow. Values over 100 J/cm(3) were estimated for volumetric heat removed from the epidermis using CSC. "Film cooling" instead of "evaporative cooling" appears to be the dominant mode of CSC on skin. Estimated values of heat removed from the epidermis suggest that a cryogen spurt as long as 200 milliseconds is required to counteract heat generated by high laser fluences (e.g., in treatment of port wine stains) in patients with high concentration of epidermal melanin. Additional cooling beyond spurt termination can be avoided by simultaneous application of airflow, although it is unclear at the moment if avoiding the additional cooling would be beneficial in the actual clinical situation. Copyright 2001 Wiley-Liss, Inc.

The theoretical risk of non-melanoma skin cancer from environmental radon exposure

International Nuclear Information System (INIS)

Eatough, J.P.; Henshaw, D.L.

1995-01-01

The skin cancer risk theoretically attributable to radon associated alpha particle radiation is calculated on the basis of recent dosimetry, and published radiation risk factors. The results suggest that of the order of 2% (range 1%-10%) of non-melanoma skin cancers in the UK may be associated with radon exposure at the average UK radon concentration of 20 Bq m -3 . The range quoted is due solely to uncertainties in the estimate of the radon dose to the basal layer of the skin, and additional sources of uncertainty are discussed. The estimate is dependent on the assumption that the target cells for radiation induced skin cancer lie in the basal layer of the epidermis, and that irradiation of the dermis is not necessary for skin cancer induction. Due to the effect of ultraviolet radiation on the risk factors for ionising radiation, ultraviolet radiation exposure must also be involved in the induction of the majority of any skin cancer cases linked to radon exposure. (author)

Skin Findings in Renal Transplantation Patients

Directory of Open Access Journals (Sweden)

Demet Kartal

2013-03-01

Full Text Available Objective: It was aimed to identify skin findings those were seen in patients who undergone renal transplantation. Methods: Patients who have been followed in Erciyes University Nephrology Hospital renal transplantation outpatient clinic were included in the study. They were evaluated for dermatologic findings during routine controls. Age, gender, transplantation date, identity of organ donor, history of medications, dermatological history and dermatological findings during examination were recorded. Biopsy was performed when needed. Results: In total 94 patients, 25 female (26.6% and 69 male (73.4%, were recruited to the study. Mean age was 36±10 years. The most frequent skin finding was drug-related acne (n=20. Most common infectious disease was verruca (n=17. There were viral disease other than verruca such as herpes zoster (n=3, superficial mycosis such as onychomycosis (n=5, tinea versicolor, tinea pedis and bacterial skin disease (n=2, and paronychia (n=1 and pre-malign lesions such as actinic cheilitis and bowenoid papulosis. Besides these, stria (n=3, kserosis (n=2, cornu cutaneum, café-au-lait spots, sebaceous hyperplasia and seborrheic dermatitis, skin tag, hypertrichosis, unguis incarinatus and calcinosis were other skin findings those were seen. No malign skin lesion was observed in any of patients. Conclusion: Miscellaneous skin lesions should develop in patients those undergone renal transplantation due to long-term utilization of various immunosuppressive drugs.

A new wall function boundary condition including heat release effect for supersonic combustion flows

International Nuclear Information System (INIS)

Gao, Zhen-Xun; Jiang, Chong-Wen; Lee, Chun-Hian

2016-01-01

Highlights: • A new wall function including heat release effect is theoretically derived. • The new wall function is a unified form holding for flows with/without combustion. • The new wall function shows good results for a supersonic combustion case. - Abstract: A new wall function boundary condition considering combustion heat release effect (denoted as CWFBC) is proposed, for efficient predictions of skin friction and heat transfer in supersonic combustion flows. Based on a standard flow model including boundary-layer combustion, the Shvab–Zeldovich coupling parameters are introduced to derive a new velocity law-of-the-wall including the influence of combustion. For the temperature law-of-the-wall, it is proposed to use the enthalpy–velocity relation, instead of the Crocco–Busemann equation, to eliminate explicit influence of chemical reactions. The obtained velocity and temperature law-of-the-walls constitute the CWFBC, which is a unified form simultaneously holding for single-species, multi-species mixing and multi-species reactive flows. The subsequent numerical simulations using this CWFBC on an experimental case indicate that the CWFBC could accurately reflect the influences on the skin friction and heat transfer by the chemical reactions and heat release, and show large improvements compared to previous WFBC. Moreover, the CWFBC can give accurate skin friction and heat flux for a coarse mesh with y"+ up to 200 for the experimental case, except for slightly larger discrepancy of the wall heat flux around ignition position.

Skin graft

Science.gov (United States)

Skin transplant; Skin autografting; FTSG; STSG; Split thickness skin graft; Full thickness skin graft ... donor site. Most people who are having a skin graft have a split-thickness skin graft. This takes ...

In vivo radiofrequency heating in swine in a 3T (123.2-MHz) birdcage whole body coil.

Science.gov (United States)

Shrivastava, Devashish; Utecht, Lynn; Tian, Jinfeng; Hughes, John; Vaughan, J Thomas

2014-10-01

To study in vivo radiofrequency (RF) heating produced due to power deposition from a 3T (Larmour frequency = 123.2 MHz), birdcage, whole body coil. The RF heating was simulated in a digital swine by solving the mechanistic generic bioheat transfer model (GBHTM) and the conventional, empirical Pennes bioheat transfer equation for two cases: 1) when the swine head was in the isocenter and 2) when the swine trunk was in the isocenter. The simulation results were validated by making direct fluoroptic temperature measurements in the skin, brain, simulated hot regions, and rectum of 10 swine (case 1: n = 5, mean animal weight = 84.03 ± 6.85 kg, whole body average SAR = 2.65 ± 0.22 W/kg; case 2: n = 5, mean animal weight = 81.59 ± 6.23 kg, whole body average SAR = 2.77 ± 0.26 W/kg) during 1 h of exposure to a turbo spin echo sequence. The GBHTM simulated the RF heating more accurately compared with the Pennes equation. In vivo temperatures exceeded safe temperature thresholds with allowable SAR exposures. Hot regions may be produced deep inside the body, away from the skin. SAR exposures that produce safe temperature thresholds need reinvestigation. Copyright © 2013 Wiley Periodicals, Inc.

Increased expression of heat shock protein 70 and heat shock factor 1 in chronic dermal ulcer tissues treated with laser-aided therapy.

Science.gov (United States)

Zhou, Jian-da; Luo, Cheng-qun; Xie, Hui-qing; Nie, Xin-min; Zhao, Yan-zhong; Wang, Shao-hua; Xu, Yi; Pokharel, Pashupati Babu; Xu, Dan

2008-07-20

Chronic dermal ulcers are also referred to as refractory ulcers. This study was conducted to elucidate the therapeutic effect of laser on chronic dermal ulcers and the induced expression of heat shock factor 1 (HSF1) and heat shock protein 70 (HSP70) in wound tissues. Sixty patients with 84 chronic dermal ulcers were randomly divided into traditional therapy and laser therapy groups. Laser treatment was performed in addition to traditional therapy in the laser therapy group. The treatment efficacy was evaluated after three weeks. Five tissue sections of healing wounds were randomly collected along with five normal skin sections as controls. HSP70-positive cells from HSP70 immunohistochemical staining were counted and the gray scale of positive cells was measured for statistical analysis. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were performed to determine the mRNA and protein expressions of HSF1 and HSP70. The cure rate of the wounds and the total efficacy in the laser therapy group were significantly higher than those in the traditional therapy group (P ulcers plays a facilitating role in healing due to the mechanism of laser-activated endogenous heat shock protection in cells in wound surfaces.

Rotating ferro-nanofluid over stretching plate under the effect of hall current and joule heating

Energy Technology Data Exchange (ETDEWEB)

Abdel-Wahed, Mohamed S., E-mail: eng_moh_sayed@live.com

2017-05-01

The behavior of boundary layer over a stretching plate filled with ferromagnetic Fe{sub 3}O{sub 4} nanoparticles and subjected to magnetic field with hall current, joule heating and nonlinear thermal radiation has been investigated. The modeling based on nonlinear partial differential equations due to continuity, momentum and heat equations, these equations transformed to a system of nonlinear ordinary differential equations using similarity transformation technique then solved numerically. The effect of hall current, joule heating and thermal radiation on the physical quantities such as surface shear stress and heat flux have been investigated and discussed. Moreover, the velocities and temperature profiles of the boundary layer under the influence of the presented external forces plotted and discussed. - Highlights: • The existence of the hall current increases the transverse velocity, as well as has a limited impact on the longitudinal velocity. • Boundary layer temperature exposed to nonlinear thermal radiation is higher than that exposed to linear thermal radiation. • Joule heating increases the boundary layer temperature near the surface especially in the linear model of thermal radiation. • Magnetic field with hall current increases the x-direction skin friction and reduces it in the y-direction.

Skin Diseases: Cross-section of human skin

Science.gov (United States)

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

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.

Fabrication of High-Temperature Heat Exchangers by Plasma Spraying Exterior Skins on Nickel Foams

Science.gov (United States)

Hafeez, P.; Yugeswaran, S.; Chandra, S.; Mostaghimi, J.; Coyle, T. W.

2016-06-01

Thermal-sprayed heat exchangers were tested at high temperatures (750 °C), and their performances were compared to the foam heat exchangers made by brazing Inconel sheets to their surface. Nickel foil was brazed to the exterior surface of 10-mm-thick layers of 10 and 40 PPI nickel foam. A plasma torch was used to spray an Inconel coating on the surface of the foil. A burner test rig was built to produce hot combustion gases that flowed over exposed face of the heat exchanger. Cooling air flowed through the foam heat exchanger at rates of up to 200 SLPM. Surface temperature and air inlet/exit temperature were measured. Heat transfer to air flowing through the foam was significantly higher for the thermally sprayed heat exchangers than for the brazed heat exchangers. On an average, thermally sprayed heat exchangers show 36% higher heat transfer than conventionally brazed foam heat exchangers. At low flow rates, the convective resistance is large (~4 × 10-2 m2 K/W), and the effect of thermal contact resistance is negligible. At higher flow rates, the convective resistance decreases (~2 × 10-3 m2 K/W), and the lower contact resistance of the thermally sprayed heat exchanger provides better performance than the brazed heat exchangers.

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

Science.gov (United States)

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

2015-01-01

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

Thermal interaction of short-pulsed laser focused beams with skin tissues

International Nuclear Information System (INIS)

Jiao Jian; Guo Zhixiong

2009-01-01

Time-dependent thermal interaction is developed in a skin tissue cylinder subjected to the irradiation of a train of short laser pulses. The skin embedded with a small tumor is stratified as three layers: epidermis, dermis and subcutaneous fat with different optical, thermal and physiological properties. The laser beam is focused to the tumor site by an objective lens for thermal therapy. The ultrafast radiation heat transfer of the focused beam is simulated by the transient discrete ordinates method. The transient Pennes bio-heat equation is solved numerically by the finite volume method with alternating direction implicit scheme. Emphasis is placed on the characterization of the focused beam propagation and absorption and the temperature rise in the focal spot. The effects of the focal spot size and location, the laser power, and the bio-heat equation are investigated. Comparisons with collimated irradiation are conducted. The focused beam can penetrate a greater depth and produce higher temperature rise at the target area, and thus reduce the possibility of thermal damage to the surrounding healthy tissue. It is ideal for killing cancerous cells and small tumors.

Thermal interaction of short-pulsed laser focused beams with skin tissues

Energy Technology Data Exchange (ETDEWEB)

Jiao Jian; Guo Zhixiong [Department of Mechanical and Aerospace Engineering, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States)], E-mail: guo@jove.rutgers.edu

2009-07-07

Time-dependent thermal interaction is developed in a skin tissue cylinder subjected to the irradiation of a train of short laser pulses. The skin embedded with a small tumor is stratified as three layers: epidermis, dermis and subcutaneous fat with different optical, thermal and physiological properties. The laser beam is focused to the tumor site by an objective lens for thermal therapy. The ultrafast radiation heat transfer of the focused beam is simulated by the transient discrete ordinates method. The transient Pennes bio-heat equation is solved numerically by the finite volume method with alternating direction implicit scheme. Emphasis is placed on the characterization of the focused beam propagation and absorption and the temperature rise in the focal spot. The effects of the focal spot size and location, the laser power, and the bio-heat equation are investigated. Comparisons with collimated irradiation are conducted. The focused beam can penetrate a greater depth and produce higher temperature rise at the target area, and thus reduce the possibility of thermal damage to the surrounding healthy tissue. It is ideal for killing cancerous cells and small tumors.

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

DEFF Research Database (Denmark)

Frahm, Ken Steffen; Andersen, Ole K.; Arendt-Nielsen, Lars

2010-01-01

Background: CO(2) 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 CO(2) 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