Search results for: epidermal thickness

Authors: Christine Li, Amanda Robertson

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Epidermal inclusion cysts occur when epidermal cells are implanted in the dermis following trauma, or surgery. They are a rare cause of an umbilical mass, with very few cases previously reported following abdominal surgery. These lesions can present with a range of symptoms, including palpable mass, pain, redness, or discharge. This paper reports a case of an umbilical epidermal inclusion cyst in a 52-year-old female presenting with a six-week history of a painful, red umbilical lump on a background of two previous diagnostic laparoscopies. Abdominal computed tomography (CT) scans revealed non-specific soft tissue thickening in the umbilical region. This was successfully treated with complete excision of the lesion. Umbilical lumps are a common presentation but can represent a diagnostic challenge. The differential diagnosis should include an epidermal inclusion cyst, particularly in a patient who has had previous abdominal surgery, including laparoscopic surgery.

Keywords: epidermal inclusion cyst, laparoscopy, umbilical mass, umbilicus

Procedia PDF Downloads 85

Authors: P. Charipoor, M. Khani, H. Mahmoudi, E. Ghasemi, P. Akbartehrani, B. Shokri

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Cold air plasma could have a variety of effects on cells and living organisms and also shows good results in medical and cosmetic cases. Herein, plasma floating electrode dielectric barrier discharge (FEDBD) plasma was designed for mouse skin rejuvenation purposes. It is safe and easy to use in clinics, laboratories, and homes. The effects of this device were investigated on mouse skin. Vitamin C ointment in combination with plasma was also used as a new method to improve FEDBD results. In this study, 20 Wistar rats were evaluated in four groups. The first group received high-dose plasma, the second group received moderate-dose plasma (with vitamin C cream), the third group received low-dose plasma (with vitamin C cream) for 6 minutes, and the fourth group received only vitamin C cream. This process was done 3 times a week for 4 weeks. Skin temperature was monitored to evaluate the thermal effect of plasma. The presence of reactive species was also demonstrated using optical spectroscopy. Mechanical assays were performed to evaluate the effect of plasma and vitamin C on the mechanical strength of the tissue, which showed a positive effect of plasma on the treated tissue compared to the control group. Using pathological and biometric skin tests, an increase in collagen levels, epidermal thickness, and an increase in fibroblasts was observed in rat skin, as well as increased skin elasticity. This study showed the positive effect of using the FEDBD plasma device on the effective parameters in skin rejuvenation.

Keywords: plasma, skin rejuvenation, collagen, epidermal thickness

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Authors: Nandita Ghosh, Shinjini Mitra, Ena Ray Banerjee

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Atopic dermatitis (AD) is a chronic disease of the skin, involving itchy, reddish, and scaly lesions. It mainly affects children and has a high prevalence in developing countries. The AD may occur due to environmental or genetic factors. There is no permanent cure for the AD. Currently, all therapeutic strategies involve methods to simply alleviate the symptoms, and include lotions and corticosteroids, which have adverse effects. Use of phytochemicals and natural products has not yet been exploited fully. The particle used in this study is derived from Cyamopsis tetragonoloba, an edible polysaccharide with a galactomannan component. The mannose component mainly increases its specificity towards cellular uptake by mannose receptors, highly expressed by the macrophage. The aim of this study was to determine the therapeutic effect of guar gum nanoparticles (GN) in vitro and in vivo in the AD. To assess the wound healing capacity of the guar gum nanoparticle (GN), we first treated adherent NIH3T3 cells, with a scratch injury, with GN. GN successfully healed the wound caused by the scratch. In the in vivo experiment, Balb/c mice ear were topically treated with oxazolone (oxa) to induce AD and then were topically treated with GN. The ear thickness was increased significantly till day 28 on the treatment of Oxa. The GN application showed a significant decrease in the thickness as assessed on day 28. The total cell count of skin cells showed fold increase when treated with oxa, was again decreased on topical application of GN on the affected skin. The eosinophil count, as assessed by Giemsa staining was also increased when treated with oxa, GN application led to a significant decrease. The IgE level was assessed in the serum samples which showed that GN helped in restoring the alleviated IgE level. The T helper cells and the macrophage population showed increased percentage when treated with oxa, the GN application. This was examined by flow cytometry. The H&E staining of the ear tissue showed epidermal thickness in the oxa treated mice, GN application showed reduced cellular filtration followed by epidermal thickness. Thus our assays showed that GN was successful in alleviating the disease caused by Oxa when administered topically.

Keywords: allergen, inflammation, nanodrug, wound

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Authors: Ghada Esheba, Fatimah Alturkistani, Arwa Obaid, Ahdab Bashehab, Moayad Alturkistani

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Introduction: Craniopharyngiomas (CPs) are rare epithelial tumors located mainly in the sellar/parasellar region. CPs have been classified histopathologically, genetically, clinically and prognostically into two distinctive subtypes: adamantinomatous and papillary variants. Aim: To examine the pattern of expression of both the β-catenin and epidermal growth factor receptor (EGFR) in surgically resected samples of adamantinomatous CP, and to asses for the possibility of using anti-EGFR in the management of ACP patients. Materials and methods: β-catenin and EGFR immunostaining was performed on paraffin-embedded tissue sections of 18 ACP cases. Result: 17 out of 18 cases (94%) of ACP exhibited strong nuclear/cytoplasmic expression of β-catenin, 15 (83%) of APC cases were positive for EGFR. Conclusion: Nuclear accumulation of β-catenin is a diagnostic hallmark of ACP. EGFR positivity in most cases of ACP could qualify the use of anti-EGFR therapy. 

Keywords: craniopharyngioma, adamantinomatous, papillary, epidermal growth factor receptor, B-catenin

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Authors: Jana Stucke, Sean Tuling, Chris Toomer

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This study focuses on the numerical investigation of the leading edge vortex (LEV) development over a 65° swept delta wing with varying thickness and maximum thickness location and their impact on its overall performance. The tested configurations are defined by a 6% and 12 % thick biconvex aerofoil with maximum thickness location at 30% and 50% of the root chord. The results are compared to a flat plate delta wing configuration of 3.4% thickness. The largest differences are observed for the aerofoils of 12% thickness and are used to demonstrate the trends and aerodynamic characteristics from here on. It was found that the vortex structure changes with change with maximum thickness and overall thickness. This change leads to not only a reduction in lift but also in drag, especially when the maximum thickness is moved forward. The reduction in drag, however, outweighs the loss in lift thus increasing the overall performance of the configuration.

Keywords: aerodynamics, CFD, delta wing, leading edge vortices

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Authors: Wei-Ting Kuo, Feng-Huei Lin

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Epidermal growth factor receptor (EGFR) is often constitutively stimulated in cancer owing to the binding of ligands such as epidermal growth factor (EGF), so it is necessary to investigate the interaction between EGFR and its targeting biomolecules which were over ligands binding. This study would focus on the binding affinity and adhesion force of two targeting products anti-EGFR monoclonal antibody (mAb) and peptide A to EGFR comparing with EGF. Surface plasmon resonance (SPR) was used to obtain the equilibrium dissociation constant to evaluate the binding affinity. Atomic force microscopy (AFM) was performed to detect adhesion force. The result showed that binding affinity of mAb to EGFR was higher than that of EGF to EGFR, and peptide A to EGFR was lowest. The adhesion force between EGFR and mAb that was higher than EGF and peptide A to EGFR was lowest. From the studies, we could conclude that mAb had better adhesion force and binding affinity to EGFR than that of EGF and peptide A. SPR and AFM could confirm the interaction between receptor and targeting ligand easily and carefully. It provide a platform to screen ligands for receptor targeting and drug delivery.

Keywords: adhesion force, binding affinity, epidermal growth factor receptor, target molecule

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Authors: Eric Lacoste

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Laboratory animals are currently widely used as a model of human pathologies in dermatology such as atopic dermatitis (AD). These models provide a better understanding of the pathophysiology of this complex and multifactorial disease, the discovery of potential new therapeutic targets and the testing of the efficacy of new therapeutics. However, confirmation of the correct development of AD is mainly based on histology from skin biopsies requiring invasive surgery or euthanasia of the animals, plus slicing and staining protocols. However, there are currently accessible imaging technologies such as Optical Coherence Tomography (OCT), which allows non-invasive visualization of the main histological structures of the skin (like stratum corneum, epidermis, and dermis) and assessment of the dynamics of the pathology or efficacy of new treatments. Briefly, female immunocompetent hairless mice (SKH1 strain) were sensitized and challenged topically on back and ears for about 4 weeks. Back skin and ears thickness were measured using calliper at 3 occasions per week in complement to a macroscopic evaluation of atopic dermatitis lesions on back: erythema, scaling and excoriations scoring. In addition, OCT was performed on the back and ears of animals. OCT allows a virtual in-depth section (tomography) of the imaged organ to be made using a laser, a camera and image processing software allowing fast, non-contact and non-denaturing acquisitions of the explored tissues. To perform the imaging sessions, the animals were anesthetized with isoflurane, placed on a support under the OCT for a total examination time of 5 to 10 minutes. The results show a good correlation of the OCT technique with classical HES histology for skin lesions structures such as hyperkeratosis, epidermal hyperplasia, and dermis thickness. This OCT imaging technique can, therefore, be used in live animals at different times for longitudinal evaluation by repeated measurements of lesions in the same animals, in addition to the classical histological evaluation. Furthermore, this original imaging technique speeds up research protocols, reduces the number of animals and refines the use of the laboratory animal.

Keywords: atopic dermatitis, mouse model, oxzolone model, histology, imaging

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Authors: M. Jalali Azizpour, H.Mohammadi Majd

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In this paper, the effect of WC-12Co particle Temperature in HVOF thermal spraying process on the coating thickness has been studied. The statistical results show that the spray distance and oxygen-to-fuel ratio are more effective factors on particle characterization and thickness of HVOF thermal spraying coatings. Spray Watch diagnostic system, scanning electron microscopy (SEM), X-ray diffraction and thickness measuring system were used for this purpose.

Keywords: HVOF, temperature, thickness, velocity, WC-12Co

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Authors: M. Jalali Azizpour

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In this paper, the effect of WC-12Co particle Temperature in HVOF thermal spraying process on the coating thickness has been studied. The statistical results show that the spray distance and oxygen-to-fuel ratio are more effective factors on particle characterization and thickness of HVOF thermal spraying coatings. Spray Watch diagnostic system, scanning electron microscopy (SEM), X-ray diffraction and thickness measuring system were used for this purpose.

Keywords: HVOF, temperature thickness, velocity, WC-12Co

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Authors: Gabi N. Nehme

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Below-knee amputees commonly experience asymmetrical gait patterns. It is generally believed that ischemia is related to the formation of pressure sores due to uneven distribution of forces. Micro-vascular responses can reveal local malnutrition. Changes in local skin blood supply under various external loading conditions have been studied for a number of years. Radionuclide clearance, photo-plethysmography, trans-cutaneous oxygen tension along with other studies showed that the blood supply would be influenced by the epidermal forces, and the rate and the amount of blood supply would decrease with increased epidermal loads being shear forces or normal forces. Several cases of socket designs were investigated using Finite Element Model (FEM) and Design of Experiment (DOE) to increase flexibility and minimize the pressure at the limb/socket interface using ultra high molecular weight polyethylene (UHMWPE) and polyamide 6 (PA6) or Duraform. The pressure reliefs at designated areas where reducing thickness is involved are seen to be critical in determination of amputees’ comfort and are very important to clinical applications. Implementing a hole between the Patellar Tendon (PT) and Distal Tibia (DT) would decrease stiffness and increase prosthesis range of motion where flexibility is needed. In addition, displacement and prosthetic energy storage increased without compromising mechanical efficiency and prosthetic design integrity.

Keywords: patellar tendon, distal tibia, prosthetic socket relief areas, hole implementation

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Authors: Jianyang Zhu, Lin Jiang, Tixian Tian

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Inspired by the increasing interesting on the wind power associated with production of clear electric power, a numerical experiment is applied to investigate the aerodynamic performance of straight type vertical axis wind turbine with different thickness and solidity, where the incompressible Navier-Stokes (N-S) equations coupled with dynamic mesh technique is solved. By analyzing the flow field, as well as energy coefficient of different thickness and solidity turbine, it is found that the thickness and solidity can significantly influence the performance of vertical axis wind turbine. For the turbine under low tip speed, the mean energy coefficient increase with the increasing of thickness and solidity, which may improve the self starting performance of the turbine. However for the turbine under high tip speed, the appropriate thickness and smaller solidity turbine possesses better performance. In addition, delay stall and no interaction of the blade and previous separated vortex are observed around appropriate thickness and solidity turbine, therefore lead better performance characteristics.

Keywords: vertical axis wind turbine, N-S equations, dynamic mesh technique, thickness, solidity

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Authors: Harish K. Arya, Kulwant Singh, R. K. Saxena

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The heat flow in weldment changes its nature from 2D to 3D with the increase in plate thickness. For welding of thicker plates the heat loss in thickness direction increases the cooling rate of plate. Since the cooling rate changes, the various bead parameters like bead penetration, bead height and bead width also got affected by it. The present study incorporates the effect of variable plate thickness on penetration and bead width. The penetration reduces with increase in plate thickness due to heat loss in thickness direction for same heat input, while bead width increases for thicker plate due to faster cooling.

Keywords: submerged arc welding, plate thickness, bead geometry, cooling rate

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Authors: Muhammad Liaqat, Hafiz Abdul Samad, Syed Talha Ali Hamdani, Yasir Nawab

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In the current research, the four layers, orthogonal through the thickness, 2D woven, 3D fabric structure was modified to improve the impact resistance of 3D fabric reinforced composites. This was achieved by imparting the auxeticity into four layers through the thickness woven structure. A comparison was made between the standard and modified four layers through the thickness woven structure in terms of auxeticity, penetration and impact resistance. It was found that the modified structure showed auxeticity in both warp and weft direction. It was also found that the penetration resistance of modified sample was less as compared to the standard structure, but impact resistance was improved up to 6.7% of modified four layers through the thickness woven structure.

Keywords: 2D woven, 3D fabrics, auxetic, impact resistance, orthogonal through the thickness

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Authors: Harish Kumar Arya, Kulwant Singh, R. K Saxena, Deepti Jaiswal

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The heat flow in weldment changes its nature from 2D to 3D with the increase in plate thickness. For welding of thicker plates the heat loss in thickness direction increases the cooling rate of plate. Since the cooling rate changes, the various bead parameters like bead penetration, bead height and bead width also got affected by it. The present study incorporates the effect of variable plate thickness on bead geometry and dilution. The penetration reduces with increase in plate thickness due to heat loss in thickness direction, while bead width and reinforcement increases for thicker plate due to faster cooling.

Keywords: submerged arc welding, plate thickness, bead geometry, cooling rate

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Authors: Rupinder Kaur, Harjot Kaur

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The objective of this paper is to present the study of the effect of varying thickness on rotating composite disks made from Al-SiC_P having different particle sizes. Mathematical modeling is used to calculate the effect of varying thickness with different particle sizes on rotating composite disks in radial as well as tangential directions with thermal gradients. In comparison to various particle sizes with varied thicknesses, long-term deformation occurs. The results are displayed visually, demonstrating how creep deformation decreases with changing particle size and thickness.

Keywords: creep, varying thickness, particle size, stresses and strain rates

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Authors: Janusz Kwaśniewski, Ireneusz Dominik, Krzysztof Lalik

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The knowledge about rock layers thickness, especially above drilled mining pavements are crucial for workers safety. The measuring systems used nowadays are generally imperfect and there is a strong demand for improvement. The application of a new type of a measurement system called Self-Excited Acoustical System is presented in the paper. The system was applied until now to monitor stress changes in metal and concrete constructions. The change in measurement methodology resulted in possibility of measuring the thickness of the rocks above the tunnels as well as thickness of a singular rock layer. The idea is to find two resonance frequencies of the self-exited system, which consists of a vibration exciter and vibration receiver placed at a distance, which are coupled with a proper power amplifier, and which operate in a closed loop with a positive feedback. The resonance with the higher amplitude determines thickness of the whole rock, whereas the lower amplitude resonance indicates thickness of a singular layer. The results of the laboratory tests conducted on a group of different rock materials are also presented.

Keywords: auto-oscillator, non-destructive testing, rock thickness measurement, geotechnic

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Authors: Koo-Yeon Kim, Eun-Hye Kim, Tae-Il Son

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Epidermal Growth Factor (EGF, Mw=6,045) has been reported to have high efficiency of wound repair and anti-wrinkle effect. However, the half-life of EGF in the body is too short to exert the biological activity effectively when applied in free form. Growth Factors can be stabilized by immobilization with carbohydrates from thermal and proteolytic degradation. Low molecular weight chitosan (LMCS) and its derivate prepared by hydrogen peroxide has high solubility. LM6A6DC was successfully prepared as a reactive carbohydrate for the stabilization of EGF by the reactions of LMCS with alkalization, tosylation, azidation and reduction. The structure of LM6A6DC was confirmed by FT-IR, 1H NMR and elementary analysis. For enhancing the stability of free EGF, EGF was attached with LM6A6DC by using water-soluble carbodiimide. EGF-LM6A6DC conjugates did not show any cytotoxicity on the Normal Human Dermal Fibroblast(NHDF) 3T3 proliferation at least under 100 ㎍/㎖. In the result, it was considered that LM6A6DC is suitable to immobilize of growth factor.

Keywords: epidermal growth factor (EGF), low-molecular-weight chitosan, immobilization

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Authors: Mahya Naghipoor

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Purpose: Non-small cell lung cancer (NSCLC) is the most common lung cancer type. Epidermal growth factor receptor (EGFR) mutation is the main reason which causes NSCLC. Computed tomography (CT) is used for diagnosis and prognosis of lung cancers because of low price and little invasion. Semantic analyses of qualitative CT features are based on visual evaluation by radiologist. However, the naked eye ability may not assess all image features. On the other hand, radiomics provides the opportunity of quantitative analyses for CT images features. The aim of this review study was comparing accuracy of semantic and radiomics features in prognosis of EGFR mutation in NSCLC. Methods: For this purpose, the keywords including: non-small cell lung cancer, epidermal growth factor receptor mutation, semantic, radiomics, feature, receiver operating characteristics curve (ROC) and area under curve (AUC) were searched in PubMed and Google Scholar. Totally 29 papers were reviewed and the AUC of ROC analyses for semantic and radiomics features were compared. Results: The results showed that the reported AUC amounts for semantic features (ground glass opacity, shape, margins, lesion density and presence or absence of air bronchogram, emphysema and pleural effusion) were %41-%79. For radiomics features (kurtosis, skewness, entropy, texture, standard deviation (SD) and wavelet) the AUC values were found %50-%86. Conclusions: In conclusion, the accuracy of radiomics analysis is a little higher than semantic in prognosis of EGFR mutation in NSCLC.

Keywords: lung cancer, radiomics, computer tomography, mutation

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Authors: Jemal Ebrahim Dessie, Zsolt Lukacs

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The wall of the aerosol can is extruded from the backward extrusion process. Necking is another forming process stage developed on the can shoulder after the backward extrusion process. Due to the thinner thickness of the wall, buckling is the critical challenge for current pure aluminum aerosol can industries. Design and investigation of extrusion with inhomogeneous wall thickness could be the best solution for reducing and optimization of neck retraction numbers. FEM simulation of inhomogeneous wall thickness has been simulated through this investigation. From axisymmetric Deform-2D backward extrusion, an aerosol can with a thickness of 0.4 mm at the top and 0.33 mm at the bottom of the aerosol can have been developed. As the result, it can optimize the number of retractions of the necking process and manufacture defect-free aerosol can shoulder due to the necking process.

Keywords: aerosol can, backward extrusion, Deform-2D, necking

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Authors: I. Algul, G. Akgun, H. Kurtaran

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Dynamic analysis of composite doubly curved panels with variable thickness subjected to different pulse types using Generalized Differential Quadrature method (GDQ) is presented in this study. Panels with variable thickness are used in the construction of aerospace and marine industry. Giving variable thickness to panels can allow the designer to get optimum structural efficiency. For this reason, estimating the response of variable thickness panels is very important to design more reliable structures under dynamic loads. Dynamic equations for composite panels with variable thickness are obtained using virtual work principle. Partial derivatives in the equation of motion are expressed with GDQ and Newmark average acceleration scheme is used for temporal discretization. Several examples are used to highlight the effectiveness of the proposed method. Results are compared with finite element method. Effects of taper ratios, boundary conditions and loading type on the response of composite panel are investigated.

Keywords: differential quadrature method, doubly curved panels, laminated composite materials, small displacement

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Authors: Junichi Hosoi

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Epidermal Langerhans cells reside in upper layer of epidermis and play a role in immune surveillance. The finding of the close association of nerve endings to Langerhans cells triggered the research on systemic regulation of Langerhans cells. They disappear from epidermis after exposure to environmental and internal stimuli and reappear about a week later. Myeloid progenitor cells are assumed to be one of the sources of Langerhans cells. We examined the effects of cortisol on the reappearance of Langerhans cells in vitro. Cord-blood derived CD34-positive cells were cultured in the medium supplemented with stem cell factor/Flt3 ligand/granulocyte macrophage-colony stimulating factor/tumor necrosis factor alpha/bone morphologic protein 7/transforming growth factor beta in the presence or absence of cortisol. Cells were analyzed by flow cytometry for CD1a (cluster differentiation 1a), a marker of Langerhans cells and dermal dendritic cells, and CD39 (cluster differentiation factor 39), extracellular adenosine triphosphatase. Both CD1a-positive cells and CD39-positive cells were decreased by treatment with cortisol (suppression by 35% and 22% compared to no stress hormone, respectively). Differentiated Langerhans cells are attracted to epidermis by chemokines that are secreted from keratinocytes. Epidermal keratinocytes were cultured in the presence or absence of cortisol and analyzed for the expression of CCL2 (C-C motif chemokine ligand 2) and CCL20 (C-C motif chemokine ligand 20), which are typical attractants of Langerhans cells, by quantitative reverse transcriptase polymerase chain reaction. The expression of both chemokines, CCL2 and CCL20, were suppressed by treatment with cortisol (suppression by 38% and 48% compared to no stress hormone, respectively). We examined the possible regulation of the suppression by cortisol with plant extracts. The extracts of Ganoderma lucidum and Iris protected the suppression of the differentiation to CD39-positive cells and also the suppression of the gene expression of LC-chemoattractants. These results suggest that cortisol, which is either systemic or locally produced, blocks the supply of epidermal Langerhans cells at 2 steps, differentiation from the precursor and attraction to epidermis. The suppression is possibly blocked by some plant extracts.

Keywords: Langerhans cell, stress, CD39, chemokine

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Authors: M. Heydari Vini

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There is a complicated relation between effective input parameters of cold rolling and output rolling force and exit thickness of strips.in many mathematical models, the effect of some rolling parameters have been ignored and the outputs have not a desirable accuracy. In the other hand, there is a special relation among input thickness of strips,the width of the strips,rolling speeds,mandrill tensions and the required exit thickness of strips with rolling force and the real exit thickness of the rolled strip. First of all, in this paper the effective parameters of cold rolling process modeled using an artificial neural network according to the optimum network achieved by using a written program in MATLAB,it has been shown that the prediction of rolling stand parameters with different properties and new dimensions attained from prior rolled strips by an artificial neural network is applicable.

Keywords: cold rolling, artificial neural networks, rolling force, real rolled thickness of strips

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Authors: Achouri Fatima, Chouicha Kaddour

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The main parameters affecting the workability are the water content, particle size, and the total surface of the grains, as long as the mixing water begins by wetting the surface of the grains and then fills the voids between the grains to form entrapped water, the quantity of water remaining is called free water. The aim is to undertake a fractal approach through the relationship between the concrete formulation parameters and workability, to develop this approach a series of concrete taken from the literature was investigated by varying formulation parameters such as G / S, the quantity of cement C and the quantity of mixing water E. We also call on other model as the model for the thickness of the water layer and model of the thickness of the paste layer to judge their relevance, hence the following results : the relevance of the model of the thickness of the water layer is considered relevant when there is a variation in the water quantity, the model of the thickness of the layer of the paste is only applicable if we consider that the paste is made with the grain value Dmax = 2.85: value from which we see a stable model.

Keywords: concrete, fractal method, paste thickness, water thickness, workability

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Authors: S. H. Abo Sabah, A. B. H. Kueh, M. A. Megat Johari, T. A. Majid

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In a recent study, a new bio-inspired honeycomb sandwich beam (BHSB) mimicking the head configuration of the woodpecker was developed. The beam consists of two carbon/epoxy composite face sheets, aluminum honeycomb core, and rubber core to enhance the repeated low-velocity impact resistance of sandwich structures. This paper aims to numerically enhance the repeated low-velocity impact resistance of the BHSB via optimizing the aluminum honeycomb core thickness. The beam was investigated employing three core thicknesses: 20 mm, 25 mm, and 30 mm at three impact energy levels (13.5 J, 15.55 J, 21.43 J). The results revealed that increasing the thickness of the aluminum honeycomb core to a certain level enhances the sandwich beam stiffness. The beam with the 25 mm honeycomb core thickness was the only beam that can sustain five repeated impacts achieving the highest impact resistance efficiency index, especially at high energy levels. Furthermore, the bottom face sheet of this beam developed the lowest stresses indicating that this thickness has a relatively better performance during impact events since it allowed minimal stress to reach the bottom face sheet. Overall, increasing the aluminum core thickness will increase the height of its cells subjecting it to buckling phenomenon. Therefore, this study suggests that the optimal thickness of the aluminum honeycomb core should be 65 % of the overall thickness of the sandwich beam to have the best impact resistance.

Keywords: sandwich beams, core thickness, impact behavior, finite element analysis, modeling

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Authors: Zeineb Seboui, Samar Dabbabi

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In this paper, we study the performance of Cu₂ZnSnS₄ (CZTS) based solar cell. In our knowledge, it is for the first time that the FTO/ZnO:Co/CZTS structure is simulated using the SILVACO-Atlas 2D simulation. Cu₂ZnSnS₄ (CZTS), ZnO:Co and FTO (SnO₂:F) layers have been deposited on glass substrates by the spray pyrolysis technique. The extracted physical properties, such as thickness and optical parameters of CZTS layer, are considered to create a new input data of CZTS based solar cell. The optimization of CZTS electron affinity and thickness is performed to have the best FTO/ZnO: Co/CZTS efficiency. The use of CZTS absorber layer with 3.99 eV electron affinity and 3.2 µm in thickness leads to the higher efficiency of 16.86 %, which is very important in the development of new technologies and new solar cell devices.

Keywords: CZTS solar cell, characterization, electron affinity, thickness, SILVACO-atlas 2D simulation

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Authors: Maryam Siyami

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Zero energy buildings refer to buildings that have zero annual energy consumption and do not produce carbon emissions. In today's world, considering the limited resources of fossil fuels, buildings, industries and other organizations have moved towards using other available energies. The idea and principle of net zero energy consumption has attracted a lot of attention because the use of renewable energy is a means and a solution to eliminate pollutants and greenhouse gases. Due to the increase in the cost of fossil fuels and their destructive effects on the environment and disrupting the ecological balance, today the plans related to zero energy principles have become very practical and have gained particular popularity. In this research, building modeling has been done in the Design Builder software environment. Based on the changes in the required energy throughout the year in different roof thickness conditions, it has been observed that with the increase in roof thickness, the amount of heating energy required has a downward trend, from 6730 kilowatt hours in the roof thickness of 10 cm to 6408 kilowatt hours in the roof thickness condition. 20 cm is reached, which represents a reduction of about 4.7% in energy if the roof thickness is doubled. Also, with the increase in the thickness of the roof throughout the year, the amount of cooling energy required has a gentle downward trend and has reached from 4964 kilowatt hours in the case of a roof thickness of 10 cm to 4859 kilowatt hours in the case of a roof thickness of 20 cm, which is a decrease equal to It displays 2%. It can be seen that the trend of changes in the energy required for cooling and heating is not much affected by the thickness of the roof (with an effect of 98%) and therefore there is no technical and economic recommendation to increase the thickness of the roof in this sector. Finally, based on the changes in the carbon dioxide produced in different states of the roof thickness, it has been observed that with the increase in the roof thickness, energy consumption and consequently the production of carbon dioxide has decreased. By increasing the thickness of the roof from 10 cm to 20 cm, the amount of carbon dioxide produced by heating the building has decreased by 27%. Also, this amount of reduction has been obtained based on the cooling system and for different amounts of roof thickness equal to 19%.

Keywords: energy consumption, green building, design builder, AHP

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Authors: Seon Soon Choi

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The fatigue crack growth is stochastic because of the fatigue behavior having an uncertainty and a randomness. Therefore, it is necessary to determine the probability distribution of a grown crack size at a specific fatigue crack propagation life for maintenance of structure as well as reliability estimation. The essential purpose of this study is to present the good probability distribution fit for the grown crack size at a specified fatigue life in a rolled magnesium alloy under different specimen thickness conditions. Fatigue crack propagation experiments are carried out in laboratory air under three conditions of specimen thickness using AZ31 to investigate a stochastic crack growth behavior. The goodness-of-fit test for probability distribution of a grown crack size under different specimen thickness conditions is performed by Anderson-Darling test. The effect of a specimen thickness on variability of a grown crack size is also investigated.

Keywords: crack size, fatigue crack propagation, magnesium alloys, probability distribution, specimen thickness

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Authors: S. D. Abdul, F. B. J. Sawa, D. Z. Andrawus, G. Dan'ilu

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Fresh leaves of twelve accessions of S. indicum were studied to examine their stomatal features, trichomes, epidermal cell shapes and anticlinal cell-wall patterns which may be used for the delimitation of the varieties. The twelve accessions of S. indicum studied have amphistomatic leaves, i.e. having stomata on both surfaces. Four types of stomatal complex types were observed namely, diacytic, anisocytic, tetracytic and anomocytic. Anisocytic type was the most common occurring on both surfaces of all the varieties and occurred 100% in varieties lale-duk, ex-sudan and ex-gombe 6. One-way ANOVA revealed that there was no significant difference between the stomatal densities of ex-gombe 6, ex-sudan, adawa-wula, adawa-ting, ex-gombe 4 and ex-gombe 2 . Accession adawa-ting (improved) has the smallest stomatal size (26.39µm) with highest stomatal density (79.08mm2) while variety adawa-wula possessed the largest stomatal size (74.31µm) with lowest stomatal density (29.60mm2), the exception was found in variety adawa-ting whose stomatal size is larger (64.03µm) but with higher stomatal density (71.54mm2). Wavy, curve or undulate anticlinal wall patterns with irregular and or isodiametric epidermal cell shapes were observed. These accessions were found to exhibit high degree of heterogeneity in their trichome features. Ten types of trichomes were observed: unicellular, glandular peltate, capitate glandular, long unbranched uniseriate, short unbranched uniseriate, scale, multicellular, multiseriate capitate glandular, branched uniseriate and stallate trichomes. The most frequent trichome type is short-unbranched uniseriate, followed by long-unbranched uniseriate (72.73% and 72.5%) respectively. The least frequent was multiseriate capitate glandular (11.5%). The high variation in trichome types and density coupled with the stomatal complex types suggest that these varieties of S. indicum probably have the capacity to conserve water. Furthermore, the leaf micromorphological features varied from one accession to another, hence, are found to be good diagnostic and additional tool in identification as well as nomenclature of the accessions of S. indicum.

Keywords: Sesamum indicum, stomata, trichomes, epidermal cells, taxonomy

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Authors: Weichao Yu, Kai Wen, Weihe Huang, Yang Yang, Jing Gong

Abstract:

Metal-loss corrosion is a major threat to the safety and integrity of gas pipelines as it may result in the burst failures which can cause severe consequences that may include enormous economic losses as well as the personnel casualties. Therefore, it is important to ensure the corroding pipeline integrity and efficiency, considering the value of wall thickness, which plays an important role in the failure probability of corroding pipeline. Actually, the wall thickness is controlled during pipe purchase stage. For example, the API_SPEC_5L standard regulates the allowable tolerance of the wall thickness from the specified value during the pipe purchase. The allowable wall thickness tolerance will be used to determine the wall thickness distribution characteristic such as the mean value, standard deviation and distribution. Taking the uncertainties of the input variables in the burst limit-state function into account, the reliability approach rather than the deterministic approach will be used to evaluate the failure probability. Moreover, the cost of pipe purchase will be influenced by the allowable wall thickness tolerance. More strict control of the wall thickness usually corresponds to a higher pipe purchase cost. Therefore changing the wall thickness tolerance will vary both the probability of a burst failure and the cost of the pipe. This paper describes an approach to optimize the wall thickness tolerance considering both the safety and economy of corroding pipelines. In this paper, the corrosion burst limit-state function in Annex O of CSAZ662-7 is employed to evaluate the failure probability using the Monte Carlo simulation technique. By changing the allowable wall thickness tolerance, the parameters of the wall thickness distribution in the limit-state function will be changed. Using the reliability approach, the corresponding variations in the burst failure probability will be shown. On the other hand, changing the wall thickness tolerance will lead to a change in cost in pipe purchase. Using the variation of the failure probability and pipe cost caused by changing wall thickness tolerance specification, the optimal allowable tolerance can be obtained, and used to define pipe purchase specifications.

Keywords: allowable tolerance, corroding pipeline segment, operation cost, production cost, reliability approach

Procedia PDF Downloads 396

Authors: Mohammad Jan-Nataj Zeinab, Kahrizi Sedighe, Bayat Noshin, Giti Torkaman

Abstract:

According to the importance of the back extensor muscle strength in postmenopausal women, this study aimed to determine the relationship between strength and changes in the thickness of back extensor muscles during isometric contraction in healthy and osteoporotic postmenopausal women. Strength and thickness of the muscles of 42 postmenopausal women were measured respectively, using a handheld dynamometer and ultrasonography. Also, the Pearson correlation coefficient was used to analyze the relationship between the strength and thickness. The results indicated a high reproducibility dynamometer test and ultrasonography. The decrease of strength in people with osteoporosis, occurred more through changes in muscle structure such as reducing the number and size of muscle fibers than changes in the nervous system part.

Keywords: back extensor muscles, strength, thickness, osteoporosis

Procedia PDF Downloads 265