Journal articles on the topic 'Skin layers'
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1
Chaudhary, Rajneesh Kumar, Dinesh Kumar, Kabindra Nath Rai, and Jitendra Singh. "Analysis of thermal injuries using classical Fourier and DPL models for multi-layer of skin under different boundary conditions." International Journal of Biomathematics 14, no. 06 (May 28, 2021): 2150040. http://dx.doi.org/10.1142/s1793524521500406.
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In this paper, the temperature distribution in the multi-layer of the skin is studied when the skin surface is subjected to most generalized boundary condition. Our skin model consists of three layers known as the epidermis, dermis, and subcutaneous layers. All layers of skin are assumed to be connected with point of interface condition and taking the barrier in between each of the two layers by symmetric flux condition and analyzing each layer separately. The classical Fourier and non-Fourier (DPL) models are extended to analyze the behavior of heat transfer in the multi-layer of the skin. The Laplace transform technique is used to derive analytical solutions for the multi-layer of skin models. The effects of the variability of different parameters such as relaxation time, layer thickness, and different types of boundary conditions on the behavior of temperature distribution in the multi-layer of skin are analyzed and discussed in detail. All the effects are shown graphically. It has been observed that during temperature distribution in the multi-layer of skin, the measurement of skin damage is less on the DPL model ([Formula: see text]) in comparison to the classical Fourier model.
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Leow, E. L., B. P. Pereira, A. K. Kour, and R. W. H. Pho. "Lifelikeness in multilayered digital prostheses." Prosthetics and Orthotics International 21, no. 1 (April 1997): 40–51. http://dx.doi.org/10.3109/03093649709164529.
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The appearance of the skin is dependent on the optical properties of the various layers of tissue and the presence of pigments. In order to reproduce the lifelikeness of the skin in developing digital prostheses, a multiple layered moulding technique was utilised. The prosthesis was moulded in two coloured layers, an outer layer and an inner layer. Four combinations of multiple coloured layers and two single coloured layers varying in their optical properties and base colours were assessed. In two groups an additional intermediate layer of detailed colours was added between the two layers, to enhance the creaselines, nails, blood vessels, and other features. All prosthesis were moulded to a total thickness of 0.6 mm. This method of moulding was based on the anatomical characteristics of the epidermal and dermal layers of the skin and their optical characteristics. The aim was to determine which combination of multiple layers gave the best outcome and made the prosthesis look lifelike in appearance. The appearance and lifelikeness of the prostheses were qualitatively assessed by a panel of assessers divided according to their vocation. The study showed that the best combination for moulding the prosthesis in multiple layers was to have the outer layer translucent and the inner layer opaque. An intermediate layer should be incorporated to enhance the more prominent surface features and the nails. The base colour of the inner layer should be darker than the outer layer to allow the intermediate layer to have a reflective background.
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Yan, Jian, Wayne G. Wamer, Paul C. Howard, Mary D. Boudreau, and Peter P. Fu. "Levels of retinyl palmitate and retinol in the stratum corneum, epidermis, and dermis of female SKH-1 mice topically treated with retinyl palmitate." Toxicology and Industrial Health 22, no. 4 (May 2006): 181–91. http://dx.doi.org/10.1191/0748233706th253oa.
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Retinyl esters are the storage form of vitamin A in skin, and retinyl palmitate (RP) accounts for the majority of the retinyl esters endogenously formed in skin. RP is also obtained exogenously through the topical application of cosmetic and skin care products that contain RP. There is limited information on the penetration and distribution of RP and vitamin Awithin the stratified layers of the skin. The purpose of these studies was to determine the time course for accumulation and disappearance of RP and retinol in the stratified layers of skin from female SKH-1 mice that received single or repeated topical applications of creams containing 0.5 or 2% of RP. We developed an HPLC method with detection limits of 5.94 and 1.62 ng, to simultaneously quantify the amount of RP and retinol, respectively, in skin samples. Our results showed that RP rapidly diffuses into the stratum corneum and epidermal skin layers within 24 h following the application of RP-containing creams. Of the three skin layers, the highest level of RP and retinol per weight unit (ng/mg) at all time points was found in the epidermis. Levels of RP and retinol were lowest in the dermal layer and intermediate in the stratum corneum. The levels of RP and retinol in the separated skin layers and in the intact skin decreased with time, but levels of RP remained higher than control values for a period of up to 18 days. Our results indicate that the application of RP to mouse skin alters the normal physiological levels of RP and retinol in the skin.
4
Journal, Baghdad Science. "Histological Structure of the Integument in Mastacembelus mastacembelus (Solander)." Baghdad Science Journal 8, no. 1 (March 6, 2011): 13–22. http://dx.doi.org/10.21123/bsj.8.1.13-22.
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The histological structure of integument in Mastacembelus mastacembelus have been investigated from skin fragments cut from nine regions at body surface. The results revealed that the integument of the fish investigated comprises three principal layers- the epidermis, the dermis (corium) and the subcutis-All the three principal layers may further be divided into secondary layers according to the function performed by their cells. The epidermis may further divided into three layers- the outermost epithelial coverage, the middle layer and the basal layer (stratum germinatiuum)-The dermis consists of a relatively thin upper layer of loose vascular connective tissue called the stratum laxum and a thick lower compact layer- the stratum compactum. The upper loose layer contains blood capillaries, nerve fibers and scale pockets. The subcutis is the innermost and the thinnest layer of the skin and is situated in between the stratum compactum and the muscles. All the above main layers showed great extend in their thickness.
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Silveira, F. E. M. "Rayleigh-Taylor Instability with Finite Skin Depth." PLASMA PHYSICS AND TECHNOLOGY 5, no. 3 (2018): 95–98. http://dx.doi.org/10.14311/ppt.2018.3.95.
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In this work, the Rayleigh-Taylor instability is addressed in a viscous-resistive current slab, by assuming a finite electron skin depth. The formulation is developed on the basis of an extended form of Ohm’s law, which includes a term proportional to the explicit time derivative of the current density. In the neighborhood of the rational surface, a viscous-resistive boundary-layer is defined in terms of a resistive and a viscous boundary layers. As expected, when viscous effects are negligible, it is shown that the viscous-resistive boundary-layer is given by the resistive boundary-layer. However, when viscous effects become important, it is found that the viscous-resistive boundary-layer is given by the geometric mean of the resistive and viscous boundary-layers. Scaling laws of the time growth rate of the Rayleigh-Taylor instability with the plasma resistivity, fluid viscosity, and electron number density are discussed.
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Kyrylovskyy, S. M. "Comparative histomorphometry of postnatal skin development of heifers of 4 breeds of base and initial genotypes." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 24, no. 108 (November 28, 2022): 119–29. http://dx.doi.org/10.32718/nvlvet10818.
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The total thickness of the skin of the heifers of the four groups increased from 3 to 18 months of postnatal ontogenesis, depending on the breed, by 16–27 %. In the heifers of the base and original genotype breeds, different periods of completion of the growth of the skin thickness were established. In all four groups of heifers, there were fundamental differences in the dynamics of the growth of the thickness of the outer integument. The thickness of the epidermal layer of the skin reached maximum values in the early postnatal ontogeny of heifers. The thickness of the layers of the dermis of the heifers of the four groups increased with age, depending on the breed, by 33–43 % – papillary and 9–24 % – reticular. In the postnatal ontogenesis of the heifers of the four groups, the noticeable increase (more than 50 %) of the papillary layer of the dermis occurred in the early age period of 3–6 months, and the dynamics of changes in the thickness of the reticular layer depended on the breed of heifers. Structural transformations of its internal organization accompanied the postnatal development of the skin of the heifers of the four groups – the ratio of skin layers changed within 5–8 %, depending on the breed. In the dynamics of postnatal ontogenesis of heifers of the base and original genotype breeds, reliable differences in the thickness of the epidermis and the reticular (together with the subcutaneous base) skin layer was manifested, as well as the parameters of the growth ratio of the papillary/reticular layers of the dermis. The dependence of the parameters of the thickness of the epidermal barrier of the skin of heifers of the four groups on the period of the year and the seasonal differences in the growth of the papillary and reticular (together with the subcutaneous base) layers of the skin of heifers of the base and original genotype breeds indicate the probable corrective effect of environmental factors on the morphology of the skin of heifers and the difference in the manifestations of adaptation.
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Radovanovic, Mira, Predrag Pudja, Vladimir Pavlovic, Jelena Miocinovic, and Aleksandar Nedeljkovic. "Microstructure of kajmak skin layer made during kajmak production." Mljekarstvo 70, no. 3 (June 18, 2020): 150–61. http://dx.doi.org/10.15567/mljekarstvo.2020.0302.
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Kajmak is a unique dairy product with a long tradition in Balkan countries and the Middle East. Kajmak skin layers are formed during 60 minutes of kajmak production, influencing the quality and determining the structure of the final product. The influence of milk composition and heat treatments (75-95 °C/5min) on the composition, microstructure and protein distribution of kajmak skin layers was investigated in this study. Microstructure was determined using scanning electron microscopy (SEM), while the distribution of protein fractions was studied by SDS PAGE in reducing and non-reducing conditions. Kajmak skin layers obtained from milk treated at common intense heat regime were characterized with β-LG and α-LA mainly as disulfide-linked complexes, while lower temperature (75 °C) caused the presence of whey proteins in dominantly individual form. More severe treatments (85 °C, 90 °C and 95 °C) caused the full involvement of β-LG in the complexes, since a certain amount of α-LA was found as a monomer. The kajmak skin layer composition, severity of the applied milk heat treatment and the linked whey proteins exhibited a very strong influence on kajmak skin layer microstructure. The microstructure of kajmak skin layer with a low fat content and fat/protein (F/P) ratio was characterized by a compact structure with a dense protein matrix. High fat content and F/P ratio resulted in a dispersive form of the stretched protein network. Kajmak skin layers produced from milk with added whey proteins were characterized by fibrous, thread-like segments, due to the incorporated denatured whey proteins, especially linked β-LG.
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Suresh Shimpi, Jitendra, and Anupama Jitendra Shimpi. "A CONCEPTUAL REVIEW ARTICLE ON TWAK W.S.R. SKIN." International Journal of Advanced Research 11, no. 04 (April 30, 2023): 1209–13. http://dx.doi.org/10.21474/ijar01/16782.
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In Ayurveda the word Twak or Charma is used for skin. Twak is referred to as due to the fact its miles that which covers the frame. This also suggests the moves of skin within the shape of pulsatility and responsiveness. Twak is the Updhatu of Mamsa. at some point of the formation of Garbha, differentiation of the layers of the skin takes region and is produced by means of all of the 3 Dosha, particularly through the Pitta Dosha. Charaka described Twacha because the Matruja Bhava (maternal issue) that is one of the six Bhava crucial in the development of foetus. Twak is Upadhatuof Mans Dhatu which paperwork the outer protecting of the frame and protects frame from outside factors such as heat, bloodless and many others. its far an important organ of the integumentary machine envelops underlying tissues and organs. Ayurveda point out the Twak as Sparshanaindrya. The layers of the Twak has been cited through extraordinary Acharyas, but the know-how of the each layer isnt always so much clear with respect to the layer stated inside the modern technology. Acharya explained the thickness of the Twak layers in as compared with the Vreehi grain and each layer has distinct thickness. concerning the formation of Twak, it was correlated with simile of formation of casein over milk. there may be a want to understand the extraordinary layer of Twak and pores and skin, their structural, useful & developmental interpretation to correlate in among them. Aims & Objectives: To review Twak from various Ayurvedic Samhita.To study and correlate twaksthara with layers of skin. Materials and methods: The literary resources for the existing have a look at was amassed by means of ayurvedic samhitaslike Charaka Samhita, Sushruta Samhita, AstangSangrah,Bhavprakasha&Sharangdharaetc. it will likely be correlated with the contemporary available books, literature, journals, web sites, and studies paper as according to correlate the possible layer of skin and its formation with the layer of the Twak and its formation process on the basis of classical information. Conclusion-The classical description regarding the Pramana of each TwakSthara has lacuna of evidence so, it can be the issue for similarly have a look at and have to be matched with the modern-day descriptions. The layer of the Twak corresponds with the layer of skin within the purposeful and structural element.
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BAUER, AARON M., ANTHONY P. RUSSELL, and ROBERT E. SHADWICK. "Mechanical Properties and Morphological Correlates of Fragile Skin in Gekkonid Lizards." Journal of Experimental Biology 145, no. 1 (September 1, 1989): 79–102. http://dx.doi.org/10.1242/jeb.145.1.79.
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The mechanical properties of gekkonid lizard skin are investigated for the first time. Although the skin of certain geckos, such as Gekko gecko, behaves in ‘typical’ vertebrate fashion, that of others, such as Ailuronyx seychellensis, exhibits unusual properties associated with identifiable morphological specializations. Light and scanning electron microscopy reveal that Ailuronyx dermis is functionally bilayered; the stratum compactum is divided into inner and outer layers by intervening loose connective tissue. The inner layer is strong and tough and does not differ significantly in its properties from that of Gekko gecko whole skin. The much thicker outer layer, however, is only 1/20 as strong and 1/50 as tough as the inner layer, and exhibits preformed zones of weakness. In nature, Ailuronyx parts with considerable portions of the outer components of the skin as an antipredator escape mechanism. Skin samples from 17 additional gecko species varied considerably in their strength, stiffness and toughness. None of the forms with tough skin employs regional integumentary loss as a predator escape strategy. Weak skin alone is not sufficient to permit regional integumentary loss, as the capability to lose the skin involves not only inherent properties of the tissue, but also features of the mechanical interaction of skin layers with one another and with the underlying body wall.
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Cao, Na, Yanhua Li, Ruoyu Zhang, Shubin Liu, Yuping Xiong, and Hui Cao. "Theoretical analysis of photoacoustic effects in a multilayered skin tissue model." AIP Advances 13, no. 3 (March 1, 2023): 035007. http://dx.doi.org/10.1063/5.0136208.
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Due to its noninvasiveness, high resolution, and high sensitivity, photoacoustic imaging has developed rapidly in the field of biomedicine. However, research on dermatosis detection by photoacoustic imaging is still lacking. In this paper, the skin is modeled as a multilayer planar medium based on the non-homogeneous, complex layered structure of the skin tissue. Then, the analytical expression for the photoacoustic signal of multilayer skin tissue was derived under the assumption that the thermal and optical parameters of the skin tissue do not vary with temperature. The expression not only considers the influence of optical, thermal, and mechanical parameters of the tissue on the photoacoustic signal but also, for the first time, the influence of the number of skin layers on the photoacoustic signal. The analytical expression of the photoacoustic signal containing the number of skin layers is also given. The numerical simulation results show that the difference between the photoacoustic signal of the seven-layer skin model and the single-layer skin model is 15.206 × 10−6 MPa when ω = 3.5 MHz and μ a = 2.70 cm−1. Therefore, the increase in the number of model layers enhances the amplitude of its photoacoustic signal. This work provides a comprehensive study of photoacoustic mechanisms in dermatosis tissues and establishes a theoretical foundation for the application of photoacoustic imaging detection technology in the diagnosis and treatment of dermatosis, which may improve treatment plans.
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Gleeson, David. "Bacterial skin infections." InnovAiT: Education and inspiration for general practice 12, no. 8 (May 21, 2019): 454–58. http://dx.doi.org/10.1177/1755738019849079.
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Every year, around 24% of the population consults their GP about a skin problem. Bacterial skin infections, especially in the paediatric and elderly populations, are common and some are potentially life-threatening. The most common bacterial pathogens associated with skin infections are Staphylococcus aureus and Staphylococcus pyogenes. This article will cover diagnosis and management of the most common skin infections, high-lighting important features of potentially lethal presentations requiring hospitalisation. Infections affecting superficial layers of the skin, deeper layers, and accessory tissues are considered.
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Bezuglyi, M. A., N. V. Bezuglaya, and S. Kostuk. "INFLUENCE OF LASER BEAM PROFILE ON LIGHT SCATTERING BY HUMAN SKIN DURING PHOTOMETRY BY ELLIPSOIDAL REFLECTORS." Devices and Methods of Measurements 9, no. 1 (March 20, 2018): 56–65. http://dx.doi.org/10.21122/2220-9506-2018-9-1-56-65.
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The correct accounting of laser emitter parameters for improvement of diagnostic authenticity of methods of optical biomedical diagnostic is important problem for applied biophotonic tasks. The purpose of the current research is estimation of influence of energy distribution profile in transversal section of laser beam on light scattering by human skin layers at photometry by ellipsoidal reflectors.Biomedical photometer with ellipsoidal reflectors for investigation of biological tissue specimens in transmitted and reflected light uses laser probing radiation with infinitely thin, Gauss-type and uniform cross-section profile. Distribution of beams with denoted profiles, which consist of 20 million photons with wavelength 632.8 nm, was modeled by using of Monte-Carlo simulation in human skin layers (corneous layer, epidermis, derma and adipose tissue) of various anatomic thickness and with ellipsoidal reflectors with focal parameter equal to 16.875 mm and eccentricity of 0.66.The modeling results represent that illuminance distribution in zones of photometric imaging is significantly influenced by the laser beam cross-section profile for various thickness of corneous layer and epidermis in transmitted and reflected light, and also derma in reflected light. Illuminance distribution for adipose tissue in reflected and transmitted light, and also derma in transmitted light, practically do not depend of laser beam profile for anatomic thicknesses, which are appropriate for human skin on various sections of body.There are represented results of modified Monte-Carlo simulation method for biomedical photometer with ellipsoidal reflectors during biometry of human skin layers. For highly scattered corneous layer and epidermis the illumination of middle and external rings of photometric images changes depending from the laser beam profile for more than 50 % in transmitted and 30 % in reflected light. For weakly scattering skin layers (derma and adipose layer) the influence of profile can be observed only for derma in reflected layer and is equal not more than 15 %.
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Kim, Jisue, Kyunghee Kim, and Gun Yong Sung. "Coenzyme Q10 Efficacy Test for Human Skin Equivalents Using a Pumpless Skin-On-A-Chip System." International Journal of Molecular Sciences 21, no. 22 (November 11, 2020): 8475. http://dx.doi.org/10.3390/ijms21228475.
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A human skin equivalent (HSE) composed of the epidermis and dermis is cultured using a pumpless skin-on-a-chip system to supply cultures the desired flow rate using gravity flow without a pump or an external tube connection. Coenzyme Q10 efficacy is tested by adjusting its concentration, as it is known to have anti-aging and antioxidant effects in culture solutions. The relationship between the contraction rate of a full-thickness human skin equivalent and secreted transforming growth factor (TGF) β-1 is analyzed via enzyme-linked immunosorbent assay (ELISA). Following hematoxylin and eosin (H&E) staining, an image of the skin equivalent is analyzed to measure the epidermal layer’s thickness. The cell density and differentiation of the dermis layer are investigated. Gene and protein expression in the dermal and epidermal layers are quantitatively analyzed using quantitative real time polymerase chain reaction (qPCR) and immunohistochemical staining. As the coenzyme Q10 treatment concentration increased, the number of cells per unit area and the thickness of the epidermal layer increased, the expression level of filaggrin increased, and the contraction rate of full-thickness HSE was proportional to the amount of TGF β-1 secreted.
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Ibrahim, Kiagus Aufa, Marlin Ramadhan Baidillah, Ridwan Wicaksono, and Masahiro Takei. "Skin layer classification by feedforward neural network in bioelectrical impedance spectroscopy." Journal of Electrical Bioimpedance 14, no. 1 (January 1, 2023): 19–31. http://dx.doi.org/10.2478/joeb-2023-0004.
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Abstract Conductivity change in skin layers has been classified by source indicator ok (k=1: Stratum corneum, k=2: Epidermis, k=3: Dermis, k=4: Fat, and k=5: Stratum corneum + Epidermis) trained from feedforward neural network (FNN) in bioelectrical impedance spectroscopy (BIS). In BIS studies, treating the skin as a bulk, limits the differentiation of conductivity changes in individual skin layers, however skin layer classification using FNN shows promise in accurately categorizing skin layers, which is essential for predicting source indicators ok and initiating skin dielectric characteristics diagnosis. The ok is trained by three main conceptual points which are (i) implementing FNN for predicting k in conductivity change, (ii) profiling four impedance inputs αξ consisting of magnitude input α| z |, phase angle input αθ , resistance input αR , and reactance input αx for filtering nonessential input, and (iii) selecting low and high frequency pair ( f r l h ) $$(f_{r}^{lh})$$ by distribution of relaxation time (DRT) for eliminating parasitic noise effect. The training data set of FNN is generated to obtain the αξ ∈ R 10×17×10 by 10,200 cases by simulation under configuration and measurement parameters. The trained skin layer classification is validated through experiments with porcine skin under various sodium chloride (NaCl) solutions CNaCl = {15, 20, 25, 30, 35}[mM] in the dermis layer. FNN successfully classified conductivity change in the dermis layer from experiment with accuracy of 90.6% for the bipolar set-up at f 6 l h = 10 & 100 [ kHz] $$f_{6}^{lh}=10\,\And 100\,{\rm{[kHz]}}$$ and with the same accuracy for the tetrapolar at f 8 l h = 35 & 100 [ kHz] $$f_{8}^{lh}=35\,\And 100\,{\rm{[kHz]}}$$ . The measurement noise and systematic error in the experimental results are minimized by the proposed method using the feature extraction based on αξ at f r l h $$f_{r}^{lh}$$ .
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T., Vijayakumat. "FLEXIBLE ROBOTIC ELECTRONIC SKIN WITH HIGH SENSITIVITY SENSOR ARRAYS." Journal of Electronics and Informatics 01, no. 01 (September 23, 2019): 43–51. http://dx.doi.org/10.36548/jei.2019.1.005.
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In this paper, we propose a flexible robotic electronic skin (e-skin) with high sensitivity sensor arrays. The sensor arrays are designed and fabricated on thin flexible silicone film. It uses piezo-resistive material Samarian Monosulphide and graphite rods for interconnection between the layers. Along with the pressure sensing capability of SmS, temperature and humidity sensors are also integrated in the silicone layers along with photovoltaic thin layer cells that provide energy independence to the module. The data procured from the e-skin is transferred to the analog to digital converter unit and further, to the PC through USB interface for analysis.
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Choi, Won Seok, Joo Hyun Kim, Chi Bum Ahn, Ji Hyun Lee, Yu Jin Kim, Kuk Hui Son, and Jin Woo Lee. "Development of a Multi-Layer Skin Substitute Using Human Hair Keratinic Extract-Based Hybrid 3D Printing." Polymers 13, no. 16 (August 4, 2021): 2584. http://dx.doi.org/10.3390/polym13162584.
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Large-sized or deep skin wounds require skin substitutes for proper healing without scar formation. Therefore, multi-layered skin substitutes that mimic the genuine skin anatomy of multiple layers have attracted attention as suitable skin substitutes. In this study, a novel skin substitute was developed by combining the multi-layer skin tissue reconstruction method with the combination of a human-derived keratinic extract-loaded nano- and micro-fiber using electrospinning and a support structure using 3D printing. A polycaprolactone PCL/keratin electrospun scaffold showed better cell adhesion and proliferation than the keratin-free PCL scaffold, and keratinocytes and fibroblasts showed better survival, adhesion, and proliferation in the PCL/keratin electrospun nanofiber scaffold and microfiber scaffold, respectively. In a co-culture of keratinocytes and fibroblasts using a multi-layered scaffold, the two cells formed the epidermis and dermal layer on the PCL/keratin scaffold without territorial invasion. In the animal study, the PCL/keratin scaffold caused a faster regeneration of new skin without scar formation compared to the PCL scaffold. Our study showed that PCL/keratin scaffolds co-cultured with keratinocytes and fibroblasts promoted the regeneration of the epidermal and dermal layers in deep skin defects. Such finding suggests a new possibility for artificial skin production using multiple cells.
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Rizk, M., L. Didierjean, and J. H. Pavlovitch. "Skin calcium binding protein: effect of ultraviolet B irradiation." American Journal of Physiology-Cell Physiology 251, no. 3 (September 1, 1986): C329—C334. http://dx.doi.org/10.1152/ajpcell.1986.251.3.c329.
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Skin calcium binding protein (SCaBP) has been found in the epidermal basal layer but not in the suprabasal layers, suggesting that its presence is correlated with the position of the cell and/or the cells' low degree of differentiation and high proliferation capacity. Rats were exposed to ultraviolet B (UVB) irradiation (280-320 nm, 0.1 J/cm2) to dissociate these two main characteristics of basal layer cells. Skin biopsy specimens were taken 24 and 48 h after UVB exposure. The [3H]thymidine labeling index, SCaBP localization (indirect immunofluorescence), and SCaBP levels monitored by radioimmunoassay were investigated. The [3H]thymidine labeling index was significantly increased after UVB treatment, and the [3H]thymidine-labeled cells were present not only in the basal layer but also in the suprabasal epidermal layers. Anti-SCaBP immunofluorescence was observed in both suprabasal and basal layers (rather than exclusively in the basal layer, as in control conditions). The radioimmunoassay indicated an overall increase in skin SCaBP content. No evidence was obtained that this increase was due to humoral factors, as no changes in SCaBP concentration on cell proliferation were observed in nonirradiated epidermal areas. Topical application of a single dose of vitamin D3, equivalent to the amount synthesized by UVB exposure, was also without effect. Thus the presence of this marker is correlated with the low degree of cell maturity and the cells' ability to proliferate rather than their basal position.
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Cokus, Shawn J., Maricruz De La Torre, Eric F. Medina, Jeffrey P. Rasmussen, Joselyn Ramirez-Gutierrez, Alvaro Sagasti, and Fang Wang. "Tissue-Specific Transcriptomes Reveal Gene Expression Trajectories in Two Maturing Skin Epithelial Layers in Zebrafish Embryos." G3: Genes|Genomes|Genetics 9, no. 10 (August 20, 2019): 3439–52. http://dx.doi.org/10.1534/g3.119.400402.
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Epithelial cells are the building blocks of many organs, including skin. The vertebrate skin initially consists of two epithelial layers, the outer periderm and inner basal cell layers, which have distinct properties, functions, and fates. The embryonic periderm ultimately disappears during development, whereas basal cells proliferate to form the mature, stratified epidermis. Although much is known about mechanisms of homeostasis in mature skin, relatively little is known about the two cell types in pre-stratification skin. To define the similarities and distinctions between periderm and basal skin epithelial cells, we purified them from zebrafish at early development stages and deeply profiled their gene expression. These analyses identified groups of genes whose tissue enrichment changed at each stage, defining gene flow dynamics of maturing vertebrate epithelia. At each of 52 and 72 hr post-fertilization (hpf), more than 60% of genes enriched in skin cells were similarly expressed in both layers, indicating that they were common epithelial genes, but many others were enriched in one layer or the other. Both expected and novel genes were enriched in periderm and basal cell layers. Genes encoding extracellular matrix, junctional, cytoskeletal, and signaling proteins were prominent among those distinguishing the two epithelial cell types. In situ hybridization and BAC transgenes confirmed our expression data and provided new tools to study zebrafish skin. Collectively, these data provide a resource for studying common and distinguishing features of maturing epithelia.
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Iuchi, Kaito, Rina Akaho, Takanori Igarashi, Nobutoshi Ojima, and Norimichi Tsumura. "Estimation of Blood Concentrations in Skin Layers with Different Depths." Color and Imaging Conference 2019, no. 1 (October 21, 2019): 290–94. http://dx.doi.org/10.2352/issn.2169-2629.2019.27.52.
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In this research, we proposed a method to estimate the concentrations of melanin and blood in different layers of skin tissue. Furthermore, we stimulated skin with a warm bath and a carbon dioxide bath and obtained spectral data by a multispectral camera six times during 18 minutes. Based on the captured image, we estimated the blood concentrations in each blood layers by the proposed method. The result showed that the blood concentration of the deep layer is increased only with the stimulation by carbon dioxide bath, and the blood concentration in the shallow layer is increased in both stimuli cases, but the rate of increase in the carbon dioxide bath was higher and the increase time was longer. Our result is consistent with the result of the previous research.
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Hou, Xiaochun, Shiying Liu, Min Wang, Christian Wiraja, Wei Huang, Peggy Chan, Timothy Tan, and Chenjie Xu. "Layer-by-Layer 3D Constructs of Fibroblasts in Hydrogel for Examining Transdermal Penetration Capability of Nanoparticles." SLAS TECHNOLOGY: Translating Life Sciences Innovation 22, no. 4 (June 20, 2016): 447–53. http://dx.doi.org/10.1177/2211068216655753.
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Nanoparticles are emerging transdermal delivery systems. Their size and surface properties determine their efficacy and efficiency to penetrate through the skin layers. This work utilizes three-dimensional (3D) bioprinting technology to generate a simplified artificial skin model to rapidly screen nanoparticles for their transdermal penetration ability. Specifically, this model is built through layer-by-layer alternate printing of blank collagen hydrogel and fibroblasts. Through controlling valve on-time, the spacing between printing lines could be accurately tuned, which could enable modulation of cell infiltration in the future. To confirm the effectiveness of this platform, a 3D construct with one layer of fibroblasts sandwiched between two layers of collagen hydrogel is used to screen silica nanoparticles with different surface charges for their penetration ability, with positively charged nanoparticles demonstrating deeper penetration, consistent with the observation from an existing study involving living skin tissue.
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Natarajan, N., and G. Suresh Kumar. "Numerical modelling of colloidal transport in fractured porous media with double layered fracture-skin." Journal of Geo-Engineering Sciences 1, no. 2 (2014): 83–94. http://dx.doi.org/10.3233/jgs-130016.
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A numerical model is developed for studying the transport of colloids in a coupled fracture-matrix system with double layer fracture-skin. The governing equations describing colloid transport along the fracture and diffusion into fracture-skin layers as well as rock-matrix, normal to the fracture axis are coupled with each other. The coupled non linear equations are solved numerically with fully implicit finite difference method. Sensitivity analysis is performed to investigate the effect of various colloid properties on the colloid concentration in the multiple porosity fractured system. Colloid remobilisation and filtration has been accounted in the model. Results suggest that the inclusion of a second fracture-skin layer has a marginal effect on the transport mechanism of colloids. As colloid velocity increases, the diffusion of colloids into the fracture-skin decreases due to the low residence time available for the colloids. High first layer fracture-skin thickness and porosity enhances the diffusion of colloids from the aqueous phase of the fracture into the skin considerably resulting in low colloidal concentration within the fracture. Variation in the porosity as well as thickness of the second layer of the fracture-skin has negligible effect on the colloidal concentration in the fracture. The colloid transport mechanism in fractured porous media is marginally affected by the multiple porosity system, or in other words additional layers of fracture skin. High filtration coefficient and low remobilisation coefficient result in low colloidal concentration within the fracture.
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Lapka, Piotr, Piotr Furmanski, and Tomasz Wisniewski. "Assessment of thermal performance of protective garments." International Journal of Numerical Methods for Heat & Fluid Flow 27, no. 5 (May 2, 2017): 1078–97. http://dx.doi.org/10.1108/hff-03-2016-0101.
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Purpose The paper aims to present the advanced mathematical and numerical models of conjugated heat and mass transfer in a multi-layer protective clothing, human skin and muscle subjected to incident external radiative heat flux. Design/methodology/approach The garment was made of three layers of porous fabric separated by the air gaps, whereas in the tissue, four skin sublayers and muscle layer were distinguished. The mathematical model accounted for the coupled heat transfer by conduction and thermal radiation with the associated phase transition of the bound water in the fabric fibres and diffusion of the water vapour in the clothing layers and air gaps. The skin and muscle were modelled with two equation model which accounted for heat transfer in the tissue and arterial blood. Complex thermal and mass transfer conditions at the internal or external boundaries between the fabric layers, air gaps and skin were assumed. Special attention was paid to modelling of thermal radiation emitted by external heat source, for example, a fire, penetrating through the protective clothing and being absorbed by the skin and muscle. Findings Temporal and spatial variations of temperature in the protective garment, skin and muscle, as well as volume fractions of the water vapour and bound water in the clothing, were calculated for various intensity of incident radiative heat flux. The results of numerical simulation were used to estimate the risk of the first-, second- and third-degree burns. Research limitations/implications Because of the small thickness of the considered system in comparison to its lateral dimensions, the presented model was limited to 1D heat and moisture transfer. The convective heat transfer through the clothing was neglected. Practical implications The model may be applied for design of the new protective clothing and for assessment of thermal performance of the various types of protective garments. Additionally, the proposed approach may be used in the medicine for estimation of degree of thermal destruction of the tissue during treatment of burns. Originality/value The novel advanced thermal model of the multi-layer protective garment, skin and muscle layer was developed. For the first time, non-grey optical properties and various optical phenomena at the internal or external boundaries between the fabric layers, air gaps and skin were accounted for during simulation of thermal interactions between the external heat source (e.g. a fire), protective clothing and human skin.
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KIM, JEONG-WEON, MIKE F. SLAVIK, CARL L. GRIFFIS, and JOEL T. WALKER. "Attachment of Salmonella typhimurium to Skins of Chicken Scalded at Various Temperatures." Journal of Food Protection 56, no. 8 (August 1, 1993): 661–65. http://dx.doi.org/10.4315/0362-028x-56.8.661.
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Microtopography of chicken skin was studied by varying scalding temperature to determine the least favorable skin surface for salmonellae attachment. Birds were scalded at 52, 56, and 60°C, and the changes of skin morphology were examined by light and transmission electron microscopy throughout the whole processing. Breast skins obtained immediately after picking were inoculated with Salmonella typhimurium, and the attachment was quantified by using scanning electron microscopy and microbiological plating techniques. Skins scalded at 52 and 56°C retained most of the epidermis, although the latter temperature caused the loss of twice as much stratum corneum layers and produced a smoother surface than the former. Skins at 60°C began to lose most of epidermal layers during scalding and exposed dermal surface after picking, which was sometimes covered with thin fragmental epidermis or basal tissue. The number of salmonellae attached to 60°C-processed skins was 1.1~1.3 logs higher than those attached to the skins processed at 52 and 56°C, as measured by scanning electron microscopy. Microbiological plating, however, showed no significant difference in attachment among three skins processed at different temperatures. This was probably due to the insensitivity of the plating method to differentiate attachment strengths of salmonellae to the skin. The above results suggest that removal of whole epidermis should be avoided in processing to reduce salmonellae attachment to the skin.
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Chen, Jieng-Chiang, and Yi-Fang Zhuang. "Tension and compression of sandwich composites with weft-knit fabric cores." Modern Physics Letters B 34, no. 07n09 (March 2, 2020): 2040004. http://dx.doi.org/10.1142/s0217984920400047.
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The manufacturing techniques of sandwich composites containing core layers of weft-knit glass fabric (WG) and weft-knit carbon fabric (WC) with carbon fabric skin layers are discussed herein. The core layers of the sandwich composites were fabricated with WG-reinforced epoxy (E) resin, WC-reinforced epoxy resin, and polyurethane foam (F). The core layer was then stacked with two pieces of carbon fabric on the top and bottom surfaces to fabricate the sandwich composites. Three sandwich composites [plain carbon fabric sandwich composite with a WG core layer (C/E/WG), plain carbon fabric sandwich composite with a WC core layer (C/E/WC), and plain carbon fabric sandwich composite with an F core layer (C/E/F)] were developed in this study. A two-step manufacturing procedure was developed to achieve sufficient adhesiveness between the skin and core layers. The tensile, flatwise compressive, and longitudinal compressive properties of these sandwich composites were measured according to referred ASTM standards on a materials test system (MTS 810). Experimental results revealed that the WC core materials displayed excellent resistance to a flatwise compressive force and the foam core material show weak resistance. Under longitudinal compression, the skin and core layer of the C/E/F specimen separated, indicating that the C/E/F specimen could not withstand longitudinal force. Moreover, the C/E/WG and C/E/WC specimens both bend at the end of the same test.
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Grigaitienė, Jūratė, Irena Marčiukaitienė, Audra Blažienė, and Anželika Chomičienė. "Study of apoptosis in normal skin tissues." Medicina 43, no. 4 (January 21, 2007): 301. http://dx.doi.org/10.3390/medicina43040037.
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The aim of the study was to investigate the apoptosis in normal human skin by examination of all epidermal layers. Material and methods. The normal skin epidermis of 15 healthy subjects was investigated by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-X nick end labeling) technique. Apoptotic cells were evaluated in the germinative and differential compartments and stratum corneum. Only highly TUNEL-positive cells with typical morphological DNA fragmentation signs were calculated. Results. In vital strata (except stratum corneum) of normal skin epidermis, 37.5% of all TUNEL-positive cells were observed in the germinative compartment and 41.7% in the granular layer of differential compartment. Conclusions. The study showed that apoptosis occurs in all layers of normal skin epidermis. It demonstrates that apoptosis is highly important in the renewal of cells and formation of epidermal structure within all compartments.
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Kumar, Nitish, Scarlet Kong, Pankaj Sharma, Xi Shi, Gaurav Vats, Stefano Checchia, Jan Seidel, Mark Hoffman, and John Daniels. "Functional surface layers in relaxor ferroelectrics." Journal of Materials Chemistry C 8, no. 23 (2020): 7663–71. http://dx.doi.org/10.1039/d0tc01300e.
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We demonstrate a unique capability to control the formation and properties of skin layer structures in relaxor ferroelectrics by adjusting defect concentration. It is shown that the skin layer is polar and both electrically and optically active.
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Jiang, Manlin, Tracy Shinners-Carnelley, Darin Gibson, Debbie Jones, Jyoti Joshi, and Gefu Wang-Pruski. "Irrigation Effect on Yield, Skin Blemishes, Phellem Formation, and Total Phenolics of Red Potatoes." Plants 11, no. 24 (December 14, 2022): 3523. http://dx.doi.org/10.3390/plants11243523.
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Dark Red Norland is an important potato cultivar in the fresh market due to its attractive bright, red colour, and good yield. However, skin blemishes such as silver patch, surface cracking, and russeting can negatively influence the tuber skin quality and marketability. It is well known that potato is a drought-sensitive plant. This study was conducted to determine whether irrigation would affect Dark Red Norland’s yield and skin quality. A three-year field trial was conducted by Peak of the Market in Manitoba, Canada. Plants were treated under both irrigation and rainfed conditions. The results show that irrigation increased the total yield by 20.6% and reduced the severity of surface cracking by 48.5%. Microscopy imaging analysis demonstrated that tubers from the rainfed trials formed higher numbers of suberized cell layers than those of the irrigated potatoes, with a difference of 0.360 to 0.652 layers in normal skins. Surface cracking and silver patch skins had more suberized cell layers than the normal skins, with ranges of 7.805 to 8.333 and 7.740 to 8.496, respectively. A significantly higher amount of total polyphenols was found in the irrigated samples with a mean of 77.30 mg gallic acid equivalents (GAE)/100 g fresh weight (fw) than that of the rainfed samples (69.80 mg GAE/100 g fw). The outcome of this study provides a better understanding of the water regime effect causing these skin blemishes, which could potentially be used to establish strategies to improve tuber skin quality and minimize market losses.
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Nair, Anroop, Shery Jacob, Bandar Al-Dhubiab, Mahesh Attimarad, and Sree Harsha. "Basic considerations in the dermatokinetics of topical formulations." Brazilian Journal of Pharmaceutical Sciences 49, no. 3 (September 2013): 423–34. http://dx.doi.org/10.1590/s1984-82502013000300004.
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Assessing the bioavailability of drug molecules at the site of action provides better insight into the efficiency of a dosage form. However, determining drug concentration in the skin layers following topical application of dermatological formulations is a great challenge. The protocols followed in oral formulations could not be applied for topical dosage forms. The regulatory agencies are considering several possible approaches such as tape stripping, microdialysis etc. On the other hand, the skin bioavailability assessment of xenobiotics is equally important for topical formulations in order to evaluate the toxicity. It is always possible that drug molecules applied on the skin surface may transport thorough the skin and reaches systemic circulation. Thus the real time measurement of molecules in the skin layer has become obligatory. In the last two decades, quite a few investigations have been carried out to assess the skin bioavailability and toxicity of topical/dermatological products. This review provides current understanding on the basics of dermatokinetics, drug depot formation, skin metabolism and clearance of drug molecules from the skin layers following application of topical formulations.
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Cardona, Cristian Rendon, Zhoushun Ruan, and Oscar Ruiz Salguero. "Skin-friction Measurements in Turbulent Boundary Layers." International Journal of Engineering and Technology 12, no. 1 (February 29, 2020): 1–15. http://dx.doi.org/10.21817/ijet/2020/v12i1/201201002.
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Aguirre, Juan, Mathias Schwarz, Dominik Soliman, Andreas Buehler, Murad Omar, and Vasilis Ntziachristos. "Broadband mesoscopic optoacoustic tomography reveals skin layers." Optics Letters 39, no. 21 (October 28, 2014): 6297. http://dx.doi.org/10.1364/ol.39.006297.
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Matsumoto, K., M. Hakozaki, and H. Shinoda. "A Robot Skin with Conductive Communication Layers." Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) 2002 (2002): 118. http://dx.doi.org/10.1299/jsmermd.2002.118_1.
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Alhacham, Eman Ibrahim Dale. "Histoarchilecture Of Skin In Guinea Pig." Kufa Journal For Veterinary Medical Sciences 8, no. 2 (December 31, 2017): 101–14. http://dx.doi.org/10.36326/kjvs/2017/v8i24115.
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The study aimes to described the histological stricture of skin in guinea pig an differention between thick and thin skin of different body regions , utilizing of (10) cutaneous specimens were taking from (6)anatomical regions including most of body which are abdomen , back, nose , ear , palmer pad and plantar pad. As the results revealed that the epidermis was thin in (ear ,abdomen and back) it composed of four secondary layers including from lower to upper: stratum Basale, Stratum Spinosum, Stratum Granulosum, and Stratum Corneum, while it was thick epidermis in nose, plantar pad , the palmer pad ,which characterized by presence of Stratum Lucidum beside the previous four layers. The study revealed a marked variation in the thickness of epidermis of the different skin regions: the thickest epidermis was in plantar pad (43.2) µm, on the contrary, the epidermis of ear region was found to be the thinnest 31.6 µm.it was also observed a direct relation between the whole thickness of the epidermis and the thickness of the Stratum corneum in all of the studied skin regions. Also we notice that the dermis composed of two essential layers. The superficial thin papillary layer which is located directly under the basement membrane and it's formed of loose and relatively cellular connective tissue and it included dermal papillae which is formed because the waves of basement membrane in different degree in anatomical regions and deep thick reticular layer which consists thick collagen fibers bundles that run parallel to the skin surface. The highest thickness of the dermis was observed in the plantar pad (36) µm, while it is reduced in the abdomen skin to (4) µm, the thickness of the other regions ranging between those two extremes .The study also clear the presence of carbohydrates in dermis more than epidermis as well as the epidermis – dermal junction is delicate in thin skin while dens in thick skin.
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Alhacham, Eman Ibrahim Dale. "Histoarchilecture Of Skin In Guinea Pig." Kufa Journal For Veterinary Medical Sciences 8, no. 2 (December 31, 2017): 101–14. http://dx.doi.org/10.36326/kjvs/2017/v8i24115.
Full textAbstract:
The study aimes to described the histological stricture of skin in guinea pig an differention between thick and thin skin of different body regions , utilizing of (10) cutaneous specimens were taking from (6)anatomical regions including most of body which are abdomen , back, nose , ear , palmer pad and plantar pad. As the results revealed that the epidermis was thin in (ear ,abdomen and back) it composed of four secondary layers including from lower to upper: stratum Basale, Stratum Spinosum, Stratum Granulosum, and Stratum Corneum, while it was thick epidermis in nose, plantar pad , the palmer pad ,which characterized by presence of Stratum Lucidum beside the previous four layers. The study revealed a marked variation in the thickness of epidermis of the different skin regions: the thickest epidermis was in plantar pad (43.2) µm, on the contrary, the epidermis of ear region was found to be the thinnest 31.6 µm.it was also observed a direct relation between the whole thickness of the epidermis and the thickness of the Stratum corneum in all of the studied skin regions. Also we notice that the dermis composed of two essential layers. The superficial thin papillary layer which is located directly under the basement membrane and it's formed of loose and relatively cellular connective tissue and it included dermal papillae which is formed because the waves of basement membrane in different degree in anatomical regions and deep thick reticular layer which consists thick collagen fibers bundles that run parallel to the skin surface. The highest thickness of the dermis was observed in the plantar pad (36) µm, while it is reduced in the abdomen skin to (4) µm, the thickness of the other regions ranging between those two extremes .The study also clear the presence of carbohydrates in dermis more than epidermis as well as the epidermis – dermal junction is delicate in thin skin while dens in thick skin.
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Al-Khafaji, Zubaidah, Sofia Brito, and Bum-Ho Bin. "Zinc and Zinc Transporters in Dermatology." International Journal of Molecular Sciences 23, no. 24 (December 18, 2022): 16165. http://dx.doi.org/10.3390/ijms232416165.
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Zinc is an important trace mineral in the human body and a daily intake of zinc is required to maintain a healthy status. Over the past decades, zinc has been used in formulating topical and systemic therapies for various skin disorders owing to its wound healing and antimicrobial properties. Zinc transporters play a major role in maintaining the integrity of the integumentary system by controlling zinc homeostasis within dermal layers. Mutations and abnormal function of zinc-transporting proteins can lead to disease development, such as spondylocheirodysplastic Ehlers–Danlos syndrome (SCD-EDS) and acrodermatitis enteropathica (AE) which can be fatal if left untreated. This review discusses the layers of the skin, the importance of zinc and zinc transporters in each layer, and the various skin disorders caused by zinc deficiency, in addition to zinc-containing compounds used for treating different skin disorders and skin protection.
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Kazimierczuk, Marian, and Rafal Wojda. "Foil Winding Resistance and Power Loss in Individual Layers of Inductors." International Journal of Electronics and Telecommunications 56, no. 3 (September 1, 2010): 237–46. http://dx.doi.org/10.2478/v10177-010-0031-2.
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Foil Winding Resistance and Power Loss in Individual Layers of InductorsThis paper presents an estimation of high-frequency winding resistance and power loss in individual inductor layers made of foil, taking into account the skin and proximity effects. Approximated equations for power loss in each layer are given and the optimal values of foil thickness for each layer are derived. It is shown that the winding resistance of individual layers significantly increases with the operating frequency and the layer number, counting from the center of an inductor. The winding resistance of each foil layer exhibits a minimum value at an optimal layer thickness. The total winding resistance increases with the total number of layers.
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Vu, Chi Cuong, and Jooyong Kim. "Simultaneous Sensing of Touch and Pressure by Using Highly Elastic e-Fabrics." Applied Sciences 10, no. 3 (February 3, 2020): 989. http://dx.doi.org/10.3390/app10030989.
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In recent years, electronic skins have been widely studied for human monitoring systems. This research field needs multi-sensing points for large deformation, strong recovery, and mass production methods. Toward these aims, the fabrication of e-fabric skins made from a capacitive touch sensing layer and a capacitive pressure sensing layer is presented in the paper. Due to the high elasticity of the dielectric layer of the spacer fabric, this structure exhibits a very fast recovery time (6 ms), low hysteresis (<5%), and high cycling stability (>20,000 times). Besides, the stacking structure of the electrode layers ( single-wall carbon nanotube/silver paste) is due to good durability even under large deformations (grasping, bending, stretching), and the skin is breathable for applications. As expected, the e-fabric skin is proven to be robust for detecting a spatial pressure distribution in real time. The extremely simple fabrication process is also an extra plus point in view of point mass production.
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Capetti, Francesca, Barbara Sgorbini, Cecilia Cagliero, Monica Argenziano, Roberta Cavalli, Luisella Milano, Carlo Bicchi, and Patrizia Rubiolo. "Melaleuca alternifolia Essential Oil: Evaluation of Skin Permeation and Distribution from Topical Formulations with a Solvent-Free Analytical Method." Planta Medica 86, no. 06 (February 25, 2020): 442–50. http://dx.doi.org/10.1055/a-1115-4848.
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Abstract Melaleuca alternifolia essential oil (tea tree oil) is widely used as an ingredient in skin care products because of its recognized biological activities. The European Scientific Committee on Consumer Products constantly promotes research and collection of data on both skin distribution and systemic exposure to tea tree oil components after the application of topical formulations. This study quantitatively evaluates permeation, skin layer distribution (stratum corneum, epidermis, and dermis), and release into the surrounding environment of bioactive tea tree oil markers (i.e., α-pinene, β-pinene, α-terpinene, 1,8-cineole, γ-terpinene, 4-terpineol, α-terpineol) when a 5% tea tree oil formulation is applied at a finite dosing regimen. Permeation kinetics were studied in vitro on pig ear skin using conventional static glass Franz diffusion cells and cells ad hoc modified to monitor the release of markers into the atmosphere. Formulation, receiving phases, and skin layers were analyzed using a fully automatic and solvent-free method based on headspace solid-phase microextraction/gas chromatography-mass spectrometry. This approach affords, for the first time, to quantify tea tree oil markers in the different skin layers while avoiding using solvents and overcoming the existing methods based on solvent extraction. The skin layers contained less than 1% of each tea tree oil marker in total. Only oxygenated terpenes significantly permeated across the skin, while hydrocarbons were only absorbed at trace level. Substantial amounts of markers were released into the atmosphere.
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Utz, S. R., D. A. Zimnyakov, E. M. Galkina, and E. M. Reshetnikova. "Optical coherence tomography and polarimetry of superficial skin biopsies." Vestnik dermatologii i venerologii 91, no. 1 (February 24, 2015): 85–91. http://dx.doi.org/10.25208/0042-4609-2015-91-1-85-91.
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The goal. Of this study was to develop and assess the efficacy of polarization probing of biotissues in vitro. The method is based on the determination of polarization parameters of scattered radiation. Materials and methods. The well-known superficial epidermis stripping method was applied using the Sulfacrylate self-sterile medical adhesive. Small portions of thin layers of the adhesive were applied to slide plates and then to different skin sites. The corneous layer in the normal condition and in case of skin diseases (psoriasis, lichen acuminatus, discoid lupus erythematosus, alopecia, itching and demodectic mange) was examined based on the optical coherence tomography (OCT) method using the 0CS1300SS device (Thorlabs Inc, USA). Results. The authors obtained pictures visualizing the structural organization of different layers of the epidermis using the superficial epidermis biopsy method in case of lichen acuminatus, hyperkeratosis, itching and other skin diseases. Conclusion. This method ensures non-invasive high-precision measurement of the structure of different layers of the epidermis, which may be useful both for research purposes and practical dermatology.
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Sridhar, A., D. I. Pullin, and W. Cheng. "Rough-wall turbulent boundary layers with constant skin friction." Journal of Fluid Mechanics 818 (March 28, 2017): 26–45. http://dx.doi.org/10.1017/jfm.2017.132.
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A semi-empirical model is presented that describes the development of a fully developed turbulent boundary layer in the presence of surface roughness with length scale $k_{s}$ that varies with streamwise distance $x$. Interest is centred on flows for which all terms of the von Kármán integral relation, including the ratio of outer velocity to friction velocity $U_{\infty }^{+}\equiv U_{\infty }/u_{\unicode[STIX]{x1D70F}}$, are streamwise constant. For $Re_{x}$ assumed large, use is made of a simple log-wake model of the local turbulent mean-velocity profile that contains a standard mean-velocity correction for the asymptotic fully rough regime and with assumed constant parameter values. It is then shown that, for a general power-law external velocity variation $U_{\infty }\sim x^{m}$, all measures of the boundary-layer thickness must be proportional to $x$ and that the surface sand-grain roughness scale variation must be the linear form $k_{s}(x)=\unicode[STIX]{x1D6FC}x$, where $x$ is the distance from the boundary layer of zero thickness and $\unicode[STIX]{x1D6FC}$ is a dimensionless constant. This is shown to give a two-parameter $(m,\unicode[STIX]{x1D6FC})$ family of solutions, for which $U_{\infty }^{+}$ (or equivalently $C_{f}$) and boundary-layer thicknesses can be simply calculated. These correspond to perfectly self-similar boundary-layer growth in the streamwise direction with similarity variable $z/(\unicode[STIX]{x1D6FC}x)$, where $z$ is the wall-normal coordinate. Results from this model over a range of $\unicode[STIX]{x1D6FC}$ are discussed for several cases, including the zero-pressure-gradient ($m=0$) and sink-flow ($m=-1$) boundary layers. Trends observed in the model are supported by wall-modelled large-eddy simulation of the zero-pressure-gradient case for $Re_{x}$ in the range $10^{8}{-}10^{10}$ and for four values of $\unicode[STIX]{x1D6FC}$. Linear streamwise growth of the displacement, momentum and nominal boundary-layer thicknesses is confirmed, while, for each $\unicode[STIX]{x1D6FC}$, the mean-velocity profiles and streamwise turbulent variances are found to collapse reasonably well onto $z/(\unicode[STIX]{x1D6FC}x)$. For given $\unicode[STIX]{x1D6FC}$, calculations of $U_{\infty }^{+}$ obtained from large-eddy simulations are streamwise constant and independent of $Re_{x}$ when this is large. The present results suggest that, in the sense that $U_{\infty }^{+}(\unicode[STIX]{x1D6FC},m)$ is constant, these flows can be interpreted as the fully rough limit for boundary layers in the presence of small-scale linear roughness.
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Abdelaziz, Ahmed, and Alia N. Mahmoud. "Skin Cancer Detection Using Deep Learning and Artificial Intelligence: Incorporated model of deep features fusion." Fusion: Practice and Applications 8, no. 1 (2022): 08–15. http://dx.doi.org/10.54216/fpa.080201.
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Among the most frequent forms of cancer, skin cancer accounts for hundreds of thousands of fatalities annually throughout the globe. It shows up as excessive cell proliferation on the skin. The likelihood of a successful recovery is greatly enhanced by an early diagnosis. More than that, it might reduce the need for or the frequency of chemical, radiological, or surgical treatments. As a result, savings on healthcare expenses will be possible. Dermoscopy, which examines the size, form, and color features of skin lesions, is the first step in the process of detecting skin cancer and is followed by sample and lab testing to confirm any suspicious lesions. Deep learning AI has allowed for significant progress in image-based diagnostics in recent years. Deep neural networks known as convolutional neural networks (CNNs or ConvNets) are essentially an extended form of multi-layer perceptrons. In visual imaging challenges, CNNs have shown the best accuracy. The purpose of this research is to create a CNN model for the early identification of skin cancer. The backend of the CNN classification model will be built using Keras and Tensorflow in Python. Different network topologies, such as Convolutional layers, Dropout layers, Pooling layers, and Dense layers, are explored and tried out throughout the model's development and validation phases. Transfer Learning methods will also be included in the model to facilitate early convergence. The dataset gathered from the ISIC challenge archives will be used to both tests and train the model.
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Taha, Emad, Samia Hekal, and Ahmed Ibrahim Nasr. "Evaluating skin quality of some rabbit breeds under Egyptian conditions." World Rabbit Science 25, no. 2 (June 28, 2017): 193. http://dx.doi.org/10.4995/wrs.2017.6652.
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Histological skin parameters in addition to mechanical and chemical properties of chrome tanned rabbits’ furs were determined in this study to evaluate and compare the quality of some rabbit breeds. Seventy-nine male rabbits aged 3 mo of New Zealand White (NZW, n=27), Rex (RX, n=24) and Gabaly (GB, n=28) were used. Results showed that GB skins had the highest values in skin weight (P<0.01) and area (P<0.05) followed by NZW and RX skins, respectively. Moreover, NZW skins differed in histological structure from the other 2 breeds, as total thickness and thickness of papillary and hypodermis layers in NZW were more than twice those of RX and GB (P<0.05). This structure is caused by an increase in fine collagen fibre bundles in papillary layer and a limited increase in larger collagen fibre bundles in the reticular layer. Furthermore, finished tanned furs properties clarify the superiority of GB furs in values of tensile and tearing strengths followed by NZW and RX, respectively. These results point to the possibility of using the chrome tanned furs of the 3 breeds in leather garment manufacturing.
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Bandyopadhyay, P. R. "Review—Mean Flow in Turbulent Boundary Layers Disturbed to Alter Skin Friction." Journal of Fluids Engineering 108, no. 2 (June 1, 1986): 127–40. http://dx.doi.org/10.1115/1.3242552.
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Recent developments in methods of reducing drag in turbulent boundary layers have been briefly reviewed. The behavior of the mean flow in several drag reducing boundary-layer flows of current interest, viz., those over longitudinal surface riblets, outer-layer devices (OLD’s), and longitudinal convex surface curvature, has been examined. The boundary layer on a surface with longitudinal concave curvature has been studied to complement the results of convex curvature. The riblets alter the flow in their vicinity only and cause no drag penalty. However, the OLD’s disturb the entire boundary layer, and it is the slow downstream (≃150 δ0) relaxation back to the equilibrium state that produces a region of lower skin friction; a net drag reduction results when the wall-drag reduction exceeds the drag penalty due to the device. The net drag reduction achieved by the riblets and OLD’s remains a modest 10 percent compared with the more spectacular levels reached by polymer addition and microbubble injection in water. Over mild convex curvatures, the outer-boundary-layer response is a function of the curvature ratio (δ0/R), and the relaxation rate after a length of convex curvature is a function of the curved length ratio (Δs0/δi). Boundary layers exhibit an asymmetric response to streamwise surface curvatures; the response is slower to a concave curvature than to a convex. Detailed turbulence and accurate wall shear stress measurements in the altered boundary layers are needed to understand the drag-reducing mechanisms involved.
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Seppänen, Aku, Milad Hallaji, and Mohammad Pour-Ghaz. "A functionally layered sensing skin for the detection of corrosive elements and cracking." Structural Health Monitoring 16, no. 2 (October 6, 2016): 215–24. http://dx.doi.org/10.1177/1475921716670574.
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In this paper, we propose an electrical impedance tomography (EIT)-based multifunctional surface sensing system, or sensing skin, for structural health monitoring. More specifically, the EIT-based sensing skin is developed for detecting and localizing the ingress of chlorides and cracking: two phenomena which are of concern in many structures, including reinforced concrete structures. The multifunctional sensing skin is made of two layers: one layer is sensitive to both chlorides and cracking, and the other layer is sensitive to cracking only. In the experiments, the sensing skin is tested on a polymeric and concrete substrate. The results demonstrate the feasibility of using the multifunctional multi-layer sensing skin for detecting and localizing corrosive elements and cracking, and for distinguishing between them.
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Macnee, Nikolai C., Ria Rebstock, Ian C. Hallett, Robert J. Schaffer, and Sean M. Bulley. "A review of current knowledge about the formation of native peridermal exocarp in fruit." Functional Plant Biology 47, no. 12 (2020): 1019. http://dx.doi.org/10.1071/fp19135.
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The outer skin layer in any plant is essential in offering a protective barrier against water loss and pathogen attack. Within fleshy fruit, the skin supports internal cell layers and can provide the initial cues in attracting seed-dispersing animals. The skin of a fruit, termed the exocarp, is a key element of consumer preference and a target for many breeding programs. Across fruiting species there is a huge diversity of exocarp types and these range from a simple single living cell layer (epidermis) often covered with a waxy layer, to complex multicellular suberised and dead cell layers (periderm), with various intermediate russet forms in between. Each exocarp can be interspersed with other structures such as hairs or spines. The epidermis has been well characterised and remains pluripotent with the help of the cells immediately under the epidermis. The periderm, in contrast, is the result of secondary meristematic activity, which replaces the epidermal layers, and is not well characterised in fruits. In this review we explore the structure, composition and mechanisms that control the development of a periderm type fruit exocarp. We draw upon literature from non-fleshy fruit species that form periderm tissue, from which a considerable amount of research has been undertaken.
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Althobaiti, Murad. "In Silico Investigation of SNR and Dermis Sensitivity for Optimum Dual-Channel Near-Infrared Glucose Sensor Designs for Different Skin Colors." Biosensors 12, no. 10 (September 29, 2022): 805. http://dx.doi.org/10.3390/bios12100805.
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Diabetes is a serious health condition that requires patients to regularly monitor their blood glucose level, making the development of practical, compact, and non-invasive techniques essential. Optical glucose sensors—and, specifically, NIR sensors—have the advantages of being non-invasive, compact, inexpensive, and user-friendly devices. However, these sensors have low accuracy and are yet to be adopted by healthcare providers. In our previous work, we introduced a non-invasive dual-channel technique for NIR sensors, in which a long channel is utilized to measure the glucose level in the inner skin (dermis) layer, while a short channel is used to measure the noise signal of the superficial skin (epidermis) layer. In this work, we investigated the use of dual-NIR channels for patients with different skin colors (i.e., having different melanin concentrations). We also adopted a Monte Carlo simulation model that takes into consideration the differences between different skin layers, in terms of blood content, water content, melanin concentration in the epidermis layer, and skin optical proprieties. On the basis of the signal-to-noise ratio, as well as the sensitivities of both the epidermis and dermis layers, we suggest the selection of wavelengths and source-to-detector separation for optimal NIR channels under different skin melanin concentrations. This work facilitates the improved design of a compact and non-invasive NIR glucose sensor that can be utilized by patients with different skin colors.
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HERYANTO, M. ARY, DENY JUANANTA, AGATA SADANARESWARI, and SARI AYU WULANDARI. "Klasifikasi Jenis Kulit Wajah menggunakan Backpropagation Neural Networks Berbasis GLCM." ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 11, no. 3 (July 25, 2023): 705. http://dx.doi.org/10.26760/elkomika.v11i3.705.
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ABSTRAKKulit wajah sangat sensitif dibandingkan dengan bagian tubuh lainnya. Ada beberapa jenis kulit wajah, yaitu normal, berminyak, dan kering. Namun, terkadang mengidentifikasi jenis kulit wajah seseorang dengan benar bisa menjadi masalah karena terdapat lima jenis kulit wajah yang berbeda. Untuk mengatasi kesulitan dalam mengidentifikasi jenis kulit wajah, pada penelitian ini diterapkan metode klasifikasi Backpropagation Neural Network berbasis GLCM. Penelitian ini menggunakan tiga jenis kulit wajah, yaitu: kering, berminyak, dan normal. Sedangkan untuk mencari model arsitektur yang tepat dilakukan dengan cara variasi jumlah hidden layer dan jumlah neuron per hidden layer. Setelah dilakukan beberapa pengujian didapatkan hasil akurasi 96.70% untuk model sembilan lapisan tersembunyi dengan enam neuron pada tiap lapisan tersembunyi.Kata kunci: kulit wajah, klasifikasi, backpropagation neural network, GLCM. ABSTRACTFacial skin is very sensitive compared to other body parts. There are several facial skin types: normal, oily, and dry. However, sometimes correctly identifying a person's facial skin type can be problematic because there are five different skin types. To overcome difficulties in identifying facial skin types, this study applied the GLCM-based Backpropagation Neural Networks classification method. This study used three types of facial skin, namely: dry, oily, and normal. Meanwhile, finding the right architectural model is done by varying the number of hidden layers and the number of neurons per hidden layer. After several tests, the results obtained an accuracy of 96.70% for the nine hidden layers model with six neurons for each hidden layer.Keywords: facial skin, classification, backpropagation neural network, GLCM.
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Sikandar, Shahbaz, Rabbia Mahum, Adham E. Ragab, Sule Yildirim Yayilgan, and Sarang Shaikh. "SCDet: A Robust Approach for the Detection of Skin Lesions." Diagnostics 13, no. 11 (May 24, 2023): 1824. http://dx.doi.org/10.3390/diagnostics13111824.
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Red, blue, white, pink, or black spots with irregular borders and small lesions on the skin are known as skin cancer that is categorized into two types: benign and malignant. Skin cancer can lead to death in advanced stages, however, early detection can increase the chances of survival of skin cancer patients. There exist several approaches developed by researchers to identify skin cancer at an early stage, however, they may fail to detect the tiniest tumours. Therefore, we propose a robust method for the diagnosis of skin cancer, namely SCDet, based on a convolutional neural network (CNN) having 32 layers for the detection of skin lesions. The images, having a size of 227 × 227, are fed to the image input layer, and then pair of convolution layers is utilized to withdraw the hidden patterns of the skin lesions for training. After that, batch normalization and ReLU layers are used. The performance of our proposed SCDet is computed using the evaluation matrices: precision 99.2%; recall 100%; sensitivity 100%; specificity 99.20%; and accuracy 99.6%. Moreover, the proposed technique is compared with the pre-trained models, i.e., VGG16, AlexNet, and SqueezeNet and it is observed that SCDet provides higher accuracy than these pre-trained models and identifies the tiniest skin tumours with maximum precision. Furthermore, our proposed model is faster than the pre-trained model as the depth of its architecture is not too high as compared to pre-trained models such as ResNet50. Additionally, our proposed model consumes fewer resources during training; therefore, it is better in terms of computational cost than the pre-trained models for the detection of skin lesions.
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Abramovich, N. D., and S. K. Dick. "A system for assessing the functional state of blood flow in the skin surface layers by the speckle structure of multiply scattered optical radiation." Doklady BGUIR 18, no. 8 (December 27, 2020): 14–20. http://dx.doi.org/10.35596/1729-7648-2020-18-8-14-20.
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Assessment of the parameters of skin microcirculation is an urgent and important task of modern medicine in the development of methods for diagnosing diseases of the nervous system. The system for assessing the functional state of blood flow in the skin surface layers in the wavelength range from 400 to 850 nm has been improved based on the use of an extended mathematical model of the propagation of optical radiation in human skin by taking into account additional parameters: optical anisotropy of the skin, diameter and shape of erythrocytes in the dermis layer, blood pressure in the brachial artery in the range from 90/60 to 195/130 mm·Hg, plasma protein concentration in the blood (α1, α2, β1, β2, γ-globulins and fibrinogen, g/l), rheological properties of blood flow with a diameter of blood vessels from 4.5 to 500 microns in the skin surface layers, skin temperature from +35 to +41 °C. The developed system makes it possible to determine the severity of microhemodynamic shifts in relation to metabolic disorders, improve diagnosis and evaluate the treatment efficacy of a number of neurological disorders; it also made it possible to reduce the patient examination time and increase the accuracy of measuring the blood flow microcirculation parameters by 10 % (linear and volumetric blood flow velocities) to detect blood flow disturbances in the surface layers of the skin in the normal and abnormal condition of the nervous system.
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Pleitez, Miguel A., Otto Hertzberg, Alexander Bauer, Tobias Lieblein, Mathias Glasmacher, Hans Tholl, and Werner Mäntele. "Infrared reflectometry of skin: Analysis of backscattered light from different skin layers." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 184 (September 2017): 220–27. http://dx.doi.org/10.1016/j.saa.2017.04.080.
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Snopenko, O. S., O. P. Timoshenko, A. Y. Ulyanitskaya, D. V. Kibkalo, N. O. Kravchenko, and G. A. Papeta. "Morphological characteristics of the skin and hair of clinically healthy dogs and cats." Veterinary science, technologies of animal husbandry and nature management, no. 6 (2020): 80–84. http://dx.doi.org/10.31890/vttp.2020.06.14.
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The article describes the histological characteristics of the skin of clinically healthy domestic dogs and cats, presents morphometric data on the thickness of the skin, layers of the epidermis, the area of the sebaceous glands and hair follicles; describes sexual and seasonal skin replacements in domestic dogs and cats, common in the east of Ukraine. The material for research is the skin of clinically healthy dogs and cats. Research method is histological. Punch-biopsy of skin fragments was performed in animals on the right from the middle of the lateral surface of the back. Fragments of skin after fixation in 10 % neutral formalin were examined by paraffin, followed by staining of slides with hematoxylin-eosin and by gelatin impregnation, staining with Sudan II, hematoxylin of Karachi. In horizontal and vertical skin sections, the following was investigated: the thickness of the epidermis, papillary and reticular layers, the length and width of the sweat and sebaceous glands, follicle of the hair, the location of hair bundles and the ratio of secondary follicles to primary ones. The histological characteristics of skin and derivatives in dogs and cats have been established. The information obtained from morphometric histostudies indicates significant fluctuations in the values in cats depending on the season; the difference in skin thickness in winter and summer reached 1407 μM and had the same parameters in females and males. The papillary and reticular layers of the dermis correlated with the total skin thickness as 53.9 and 60.3 % in winter and 45.4 and 38.7% in summer, respectively. Epidermal seasonal changes were less significant. The papillary layer of the skin of the domestic cat was more developed than the reticular layer, in contrast to the dogs. The area of the basal sebaceous glands in cats averaged 0.05 mm2 in summer and 0.013 mm2 in winter. In domestic dogs, skin thickness and hair density did not depend on seasonal changes, but on the sex of the animals; in females, the skin was on average 496 + 183 microns thick, and the density was not significantly higher than in males. The area of the sebaceous glands averaged 0,020 mm2 in dog, in cats 0.013 mm2 in summer and in winter – 0.05 mm2.