Search results for: nano collagen molecules

Authors: Saba Pajuhan, Afshin Farahbakhsh, S. M. M. Dastgheib

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Biosurfactants and bioemulsifiers are a structurally diverse group of surface-active molecules synthesized by microorganisms, they are amphipathic molecules which reduce surface and interfacial tensions and widely used in pharmaceutical, cosmetic, food and petroleum industries. In this paper, several methods of bioemulsifer synthesis and purification by Bacillus licheniformis strains (namely ACO1, PTCC 1595 and ACO4) were investigated. Strains were grown in nutrient broth with different conditions in order to get maximum production of bioemulsifer. The purification of bio emulsifier and the quality evaluation of the product was done by adding sulfuric acid (H₂SO₄) (98%), Ethanol or HCl to the solution followed by centrifuging. To determine the optimal conditions yielding the highest bioemulsifier production, the effect of various carbon and nitrogen sources, temperature, NaCl concentration, pH, O₂ levels, incubation time are indispensable and all of them were highly effective in bioemulsifiers production.

Keywords: biosurfactant, bioemulsifier, purification, surface tension, interfacial tension

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Authors: Yaseen Elhebshi, Abdulkareem Hamid, Nureddin Bin Issa, Xiaonong Chen

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A convenient method of preparing ultrafine polystyrene latex nano-particles with amino groups on the surface is developed. Polystyrene latexes in the size range 50–400 nm were prepared via emulsion polymerization, using sodium dodecyl sulfate (SDS) as surfactant. Polystyrene with amino groups on the surface will be fine to use as organic filler to modify rubber. Transmission electron microscopy (TEM) was used to observe the morphology of silicon dioxide and functionalized polystyrene nano-particles. The nature of bonding between the polymer and the reactive groups on the filler surfaces was analyzed using Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was employed to examine the filler surface.

Keywords: reactive filler, emulsion polymerization, particle size, polystyrene nanoparticles

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Authors: Farnaz Fotovvatikhah, Javad Akbari

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Test time of a test architecture is an important factor which depends on the architecture's delay and test patterns. Here a new architecture to store the test results based on network on chip is presented. In addition, simple analytical model is proposed to calculate link test time for built in self-tester (BIST) and external tester (Ext) in multiprocessor systems. The results extracted from the model are verified using FPGA implementation and experimental measurements. Systems consisting 16, 25, and 36 processors are implemented and simulated and test time is calculated. In addition, BIST and Ext are compared in terms of test time at different conditions such as at different number of test patterns and nodes. Using the model the maximum frequency of testing could be calculated and the test structure could be optimized for high speed testing.

Keywords: test, nano on-chip network, JTAG, modelling

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Authors: Judith Stein, Elfriede Friedmann

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The injection of a drug into the vitreous body for the treatment of retinal diseases like wet aged-related macular degeneration (AMD) is the most common medical intervention worldwide. We develop mathematical models for drug transport in the vitreous body of a human eye to analyse the impact of different rheological models of the vitreous on drug distribution. In addition to the convection diffusion equation characterizing the drug spreading, we use porous media modeling for the healthy vitreous with a dense collagen network and include the steady permeating flow of the aqueous humor described by Darcy's law driven by a pressure drop. Additionally, the vitreous body in a healthy human eye behaves like a viscoelastic gel through the collagen fibers suspended in the network of hyaluronic acid and acts as a drug depot for the treatment of retinal diseases. In a completely liquefied vitreous, we couple the drug diffusion with the classical Navier-Stokes flow equations. We prove the global existence and uniqueness of the weak solution of the developed initial-boundary value problem describing the drug distribution in the healthy vitreous considering the permeating aqueous humor flow in the realistic three-dimensional setting. In particular, for the drug diffusion equation, results from the literature are extended from homogeneous Dirichlet boundary conditions to our mixed boundary conditions that describe the eye with the Galerkin's method using Cauchy-Schwarz inequality and trace theorem. Because there is only a small effective drug concentration range and higher concentrations may be toxic, the ability to model the drug transport could improve the therapy by considering patient individual differences and give a better understanding of the physiological and pathological processes in the vitreous.

Keywords: coupled PDE systems, drug diffusion, mixed boundary conditions, vitreous body

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Authors: M. Hosseinnejad, K. Gharanjig

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In the present study, metal free organic dyes were prepared and used as photo-sensitizers in dye-sensitized solar cells. Double rhodanine was utilized as the fundamental electron acceptor group to which electron donor aldehyde with varying substituents was attached to produce new organic dye. This dye was first purified and then characterized by analytical techniques. Spectrophotometric evaluations of the prepared dye in solution and on a nano anatase TiO₂ substrate were carried out in order to assess possible changes in the status of the dyes in different environments. The results show that the dye form j-type aggregates on the nano TiO₂. Additionally, oxidation potential measurements were also carried out. Finally, dye sensitized solar cell based on synthesized dye was fabricated in order to determine the photovoltaic behavior and conversion efficiency of individual dye.

Keywords: conversion efficiency, dye-sensitized solar cell, photovoltaic behavior, sensitizer

Procedia PDF Downloads 181

Authors: Seokyoon Moon, Yun-Ho Ahn, Heejoong Kim, Sujin Hong, Yunseok Lee, Youngjune Park

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Gas hydrate is a non-stoichiometric crystalline compound consisting of host water-framework and low molecular weight guest molecules. Small gaseous molecules such as CH₄, CO₂, and N₂ can be captured in the host water framework lattices of the gas hydrate with specific temperature and pressure conditions. The three well-known crystal structures of structure I (sI), structure II (sII), and structure H (sH) are determined by the size and shape of guest molecules. In this study, we measured the phase equilibria of binary (2,2-dimethyl-1-propanol + CO₂, CH₄, N₂) hydrates to explore their fundamental thermodynamic characteristics. We identified the structure of the binary gas hydrate by employing synchrotron high-resolution powder diffraction (HRPD), and the guest distributions in the lattice of gas hydrate were investigated via dispersive Raman and ¹³C solid-state nuclear magnetic resonance (NMR) spectroscopies. The end-to-end distance of 2,2-dimethyl-1-propanol was calculated to be 7.76 Å, which seems difficult to be enclathrated in large cages of sI or sII. However, due to the flexibility of the host water framework, binary hydrates of sI or sII types can be formed with the help of small gas molecule. Also, the synchrotron HRPD patterns revealed that the binary hydrate structure highly depends on the type of help gases; a cubic Fd3m sII hydrate was formed with CH₄ or N₂, and a cubic Pm3n sI hydrate was formed with CO₂. Interestingly, dispersive Raman and ¹³C NMR spectra showed that the unique tuning phenomenon occurred in binary (2,2-dimethyl-1-propanol + CO₂) hydrate. By optimizing the composition of NPA, we can achieve both thermodynamic stability and high CO₂ storage capacity for the practical application to CO₂ capture.

Keywords: clathrate, gas hydrate, neopentyl alcohol, CO₂, tuning phenomenon

Procedia PDF Downloads 239

Authors: O. D. Arbeláez-Echeverri, E. Restrepo-Parra, J. C. Riano-Rojas

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A two dimensional geometric model of Bit Patterned Media is proposed, the model is based on the crystal structure of the materials commonly used to produce the nano islands in bit patterned materials and the possible defects that may arise from the interaction between the nano islands and the matrix material. The dynamic magnetic properties of the material are then computed using time aware integration methods for the multi spin Hamiltonian. The Hamiltonian takes into account both the spatial and topological disorder of the sample as well as the high perpendicular anisotropy that is pursued when building bit patterned media. The main finding of the research was the possibility of replicating the results of previous experiments on similar materials and the ability of computing the switching field distribution given the geometry of the material and the parameters required by the model.

Keywords: nanostructures, Monte Carlo, pattern media, magnetic properties

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Authors: Bingjie Wang, Su-Yeon Kwon, Ik-Joong Kang

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The goal of this experiment is to develop a sensor that can quickly check the concentration by using the nanoparticles made by chitosan and gold. Using chitosan nanoparticles crosslinking with sodium tripolyphosphate(TPP) is the first step to form the chitosan nanoparticles, which would be covered with the gold sequentially. The size of the fabricated product was around 100nm. Based on the method that the sulfur end of the MPA linked to gold can form the very strong S–Au bond, and the carboxyl group, the other end of the MPA, can easily absorb the GABA. As for the GABA, what is the primary inhibitory neurotransmitter in the mammalian central nervous system in the human body. It plays such significant role in reducing neuronal excitability pass through the nervous system. A Surface-enhanced Raman Scattering (SERS) as the principle for enhancing Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures is used to detect the concentration change of γ-Aminobutyric Acid (GABA). When the system is formed, it generated SERS, which made a clear difference in the intensity of Raman scattering within the range of GABA concentration. So it is obtained from the experiment that the calibration curve according to the GABA concentration relevant with the SERS scattering. In this study, DLS, SEM, FT-IR, UV, SERS were used to analyze the products to obtain the conclusion.

Keywords: mercaptopropionic acid, chitosan-gold nanoshell, γ-aminobutyric acid, surface-enhanced raman scattering

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Authors: Hideo Sawada

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Fluoroalkyl end-capped oligomers [RF-(M)n-RF; RF = fluoroalkyl groups; M = radical polymerizable monomers] can form nanometre size-controlled self-assembled oligomeric aggregates through the aggregations of end-capped fluoroalkyl groups. Fluoroalkyl end-capped oligomeric aggregates can also interact with guest molecules to afford fluorinated aggregate/guest molecule nanocomposites; although the corresponding non-fluorinated oligomers cannot form such molecular aggregates to interact with guest molecules. For example, silica nanoparticles should act as guest molecules in fluorinated oligomeric aggregate cores to give new fluorinated oligomer-coated silica nanoparticles (fluorinated oligomer/silica nanocomposites). In these fluoroalkyl end-capped oligomers/silica nanocomposites, some fluorinated oligomers/silica nanocomposites were found to exhibit no weight loss behavior corresponding to the contents of oligomers in the silica matrices even after calcination at 800 oC. Fluoroalkyl end-capped vinyltrimethoxysilane oligomer-coated silica nanoparticles can be prepared by the sol-gel reaction of the corresponding fluorinated oligomer under alkaline conditions. The modified glass surface treated with this fluorinated oligomeric nanoparticle exhibited a completely super-hydrophobic characteristic. These fluorinated nanoparticles were also applied to the surface modification possessing a super-oleophobic characteristic. Not only fluoroalkyl end-capped oligomers but also low molecular weight fluorinated surfactants such as perfluoro-1,3-propanedisulfonic acid (PFPS) were applied to the preparation of fluorinated surfactants/silica nanocomposites to give no weight loss in proportion to the content of the surfactants in the nanocomposites even after calcination at 800 oC.

Keywords: fluorinated oligomer, silica nanocomposite, nonflammable characteristic, superamphiphobic chracteristic

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Authors: Naresh Radaliyagoda, Nigel M. Jennett, Rong Lan, David Parfitt

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A series of length scale engineered multilayer material with temperature robust mechanical properties has been suggested. A range of polycrystalline copper sub-layers with the thickness varying from 1 to 25μm and buried in between two nickel layers was produced using electrodeposition dual bath technique. The structure of the multilayers was characterized using Electron Backscatter Diffraction and Scanning Electron Microscope. The interface effect on the hardness and elastic modulus was tested using Nano-indentation. Results of the grain size and layer thickness measurements, and indentation hardness have been compared. It is found that there is a combined length scale effect that improves mechanical properties in Ni/Cu multilayer structures.

Keywords: nano-indentation, size effect, multilayers, electrodeposition

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Authors: Kaarunya Sampathkumar, Say Chye Joachim Loo

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Oral delivery is regarded as the facile method for the administration of active pharmaceutical ingredients (API) and drug carriers. In an initiative towards sustainable nanotechnology, an oral nano-delivery system has been developed that is made entirely of food-based materials and can also act as a site-specific delivery device depending on the stimulus encountered in different parts of the gastrointestinal tract (GIT). The delivery system has been fabricated from food grade polysaccharide materials like chitosan and starch through electrospraying technique without the use of any organic solvents. A nutraceutical extracted from an Indian medicinal plant, has been loaded into the nano carrier to test its efficacy in encapsulation and stimuli based release of the active ingredient. The release kinetics of the nutraceutical from the carrier was evaluated in simulated gastric, intestinal and colonic fluid and was found to be triggered both by the enzymes and the pH in each part of the intestinal tract depending on the polysaccharide being used. The toxicity of the nanoparticles on the intestinal epithelial cells was tested and found to be relatively safe for up to 24 hours at a concentration of 0.2 mg/mL with cellular uptake also being observed. The developed nano carrier thus serves as a promising delivery vehicle for targeted delivery to different parts of the GIT with the inherent conditions of the GIT itself acting as the stimulus. In addition, being fabricated from food grade materials, the carrier could be potentially used for the targeted delivery of nutrients through functional foods.

Keywords: bioavailability, chitosan, delivery systems, encapsulation

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Authors: Fatemeh Safdari, Amirnaser Shamkhali, Gholamabbas Parsafar

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Carbon nanostructures are of great importance in academic research and industry, which can be mentioned to chemical sensors, catalytic processes, pharmaceutical and environmental issues. Common point in all of these applications is the occurrence of adsorption of molecules on these structures. Important carbon nanostructures in this case are mainly nanotubes and graphene. To modify pure graphene, recently, many experimental and theoretical studies have carried out to investigate of metal adsorption on graphene. In this work, the adsorption of CO molecules on pure graphene and on metal adatom on graphene surface has been simulated based on density functional theory (DFT). All calculations were performed by PBE functional and Troullier-Martins pseudopotentials. Density of states (DOS) for graphene-CO, graphen and CO around the Fermi energy has been moved and very small mixing occured which implies the physisorption of CO on the bare graphen surface. While, the results have showed that CO adsorption on transition-metal adatom on graphene surface is chemisorption.

Keywords: adsorption, density functional theory, graphene, metal adatom

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Authors: Tejinder Pal Singh, Ravinder Kumar Malik, Gurpreet Kaur

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Adhesion is key factor for colonization of the gastrointestinal tract and the ability of probiotic strains to inhibit pathogens. Therefore, the adhesion ability is considered as a suitable biomarker for the selection of potential probiotic. In the present study, eight probiotic Lactobacillus reuteri strains were evaluated as viable, LiCl treated or heat-killed forms and compared with probiotic reference strains (L. reuteri ATCC55730). All strains investigated were able to adhere to Caco-2 cells. All probiotic L. reuteri strains tested were able to inhibit and displace (P < 0.05) the adhesion of Escherichia coli ATCC25922, Salmonella typhi NCDC113, Listeria monocytogenes ATCC53135 and Enterococcus faecalis NCDC115. The probiotic strain L. reuteri LR6 showed the strongest adhesion and pathogen inhibition ability among the eight L. reuteri strains tested. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting the involvement of various mechanisms. The adhesion and antagonistic potential of the probiotic strains were significantly decreased upon exposure to 5M LiCl, showing that surface molecules, proteinaceous in nature, are involved. The heat-killed forms of the probiotic L. reuteri strains also inhibited the attachment of selected pathogens to Caco-2 cells. In conclusion, in vitro assays showed that L. reuteri strains, as viable or heat-killed forms, are adherent to Caco-2 cell line model and are highly antagonistic to selected pathogens in which surface molecules, proteinaceous molecules in particular, plays an important role.

Keywords: probiotics, Lactobacillus reuteri, adhesion, Caco-2 cells

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Authors: K. Selvakumar, J. Kalaiselvimary, B. Jansirani, M. Ramesh Prabhu

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Proton conducting sulphonated poly (vinylidene fluoride- hexafluoro propylene) PVdF-HFP membranes were modified with nano – sized montmorillonite (MMT) through homogeneous dispersive mixing and solution casting technique for fuel cell applications. The prepared composite membranes were characterized using Fourier Transform Infrared Spectroscopy and 1HNMR technique. The suitability of the composite membranes for fuel cell application was evaluated in terms of water uptake, swelling behavior, and proton conductivity. These composites showed good conductivities and durability and expected to be used in the development of proton exchange membrane for fuel cells.

Keywords: composite, proton conduction, sulphonation, water uptake

Procedia PDF Downloads 245

Authors: F. Kashanian, M. M. Masoudi, A. Akbari, A. Shamloo, M. R. Zand, S. S. Salehi

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Nano-sized materials present new opportunities in biology and medicine and they are used as biomedical tools for investigation, separation of molecules and cells. To achieve more effective cancer therapy, it is essential to select cancer cells exactly. This research suggests that using the antibody-functionalized nontoxic Arginine-doped magnetic nanoparticles (A-MNPs), has been prosperous in detection, capture, and magnetic separation of circulating tumor cells (CTCs) in tumor tissue. In this study, A-MNPs were synthesized via a simple precipitation reaction and directly immobilized Ep-CAM EBA-1 antibodies over superparamagnetic A-MNPs for Mucin BCA-225 in breast cancer cell. The samples were characterized by vibrating sample magnetometer (VSM), FT-IR spectroscopy, Tunneling Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). These antibody-functionalized nontoxic A-MNPs were used to capture breast cancer cell. Through employing a strong permanent magnet, the magnetic separation was achieved within a few seconds. Antibody-Conjugated nontoxic Arginine-doped Fe₃O₄ nanoparticles have the potential for the future study to capture CTCs which are released from tumor tissue and for drug delivery, and these results demonstrate that the antibody-conjugated A-MNPs can be used in magnetic hyperthermia techniques for cancer treatment.

Keywords: tumor tissue, antibody, magnetic nanoparticle, CTCs capturing

Procedia PDF Downloads 359

Authors: Kkochorong Park, Keun Cheon Kim, Hyoban Lee, Eun Ju Lee, Bongsoo Kim

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Introduction of biomaterials such as DNA, RNA, proteins is important for many research areas. There are many methods to introduce biomaterials into living organisms like tissue and cells. To introduce biomaterials, several indirect methods including virus‐mediated delivery, chemical reagent (i.e., lipofectamine), electrophoresis have been used. Such methods are passive delivery using an endocytosis process of cell, reducing an efficiency of delivery. Unlike the indirect delivery method, it has been reported that a direct delivery of exogenous biomolecules into nucleus have been more efficient to expression or integration of biomolecules. Nano-sized material is beneficial for detect signal from cell or deliver stimuli/materials into the cell at cellular and molecular levels, due to its similar physical scale. Especially, because 1 dimensional (1D) nanomaterials such as nanotube, nanorod and nanowire with high‐aspect ratio have nanoscale geometry and excellent mechanical, electrical, and chemical properties, they could play an important role in molecular and cellular biology. In this study, by using single crystalline 1D noble metal nanowire, we fabricated nano-sized 1D injector which can successfully interface with living cells and directly deliver biomolecules into several types of cell line (i.e., stem cell, mammalian embryo) without inducing detrimental damages on living cell. This nano-bio technology could be a promising and robust tool for introducing exogenous biomaterials into living organism.

Keywords: DNA, gene delivery, nanoinjector, nanowire

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Authors: Feixiong Chen, Naoufel Haddour, Marie Frenea-Robin, Yves MéRieux, Yann Chevolot, Virginie Monnier

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Neonatal thrombopenia occurs when the mother generates antibodies against her baby’s platelet antigens. It is particularly critical for newborns because it can cause coagulation troubles leading to intracranial hemorrhage. In this case, diagnosis must be done quickly to make platelets transfusion immediately after birth. Before transfusion, platelet antigens must be tested carefully to avoid rejection. The majority of thrombopenia (95 %) are caused by antibodies directed against Human Platelet Antigen 1a (HPA-1a) or 5b (HPA-5b). The common method for antigen platelets detection is polymerase chain reaction allowing for identification of gene sequence. However, it is expensive, time-consuming and requires significant blood volume which is not suitable for newborns. We propose to develop a point-of-care device based on double functionalized magnetic colloids with 1) antibodies specific to antigen platelets and 2) highly sensitive electroactive molecules in order to be detected by an electrochemical microsensor. These magnetic colloids will be used first to isolate platelets from other blood components, then to capture specifically platelets bearing HPA-1a and HPA-5b antigens and finally to attract them close to sensor working electrode for improved electrochemical signal. The expected advantages are an assay time lower than 20 min starting from blood volume smaller than 100 µL. Our functionalization procedure based on amine dendrimers and NHS-ester modification of initial carboxyl colloids will be presented. Functionalization efficiency was evaluated by colorimetric titration of surface chemical groups, zeta potential measurements, infrared spectroscopy, fluorescence scanning and cyclic voltammetry. Our results showed that electroactive molecules and antibodies can be immobilized successfully onto magnetic colloids. Application of a magnetic field onto working electrode increased the detected electrochemical signal. Magnetic colloids were able to capture specific purified antigens extracted from platelets.

Keywords: Magnetic Nanoparticles , Electroactive Molecules, Antibody, Platelet

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Authors: Kamila Duś-Szachniewicz, Kinga M. Walaszek, Paweł Skiba, Paweł Kołodziej, Piotr Ziółkowski

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Cell adhesion is of fundamental importance in the cell communication, signaling, and motility, and its dysfunction occurs prevalently during cancer progression. The knowledge of the molecular and cellular processes involved in abnormalities in cancer cells adhesion has greatly increased, and it has been focused mainly on cellular adhesion molecules (CAMs) and tumor microenvironment. Unfortunately, most of the data regarding CAMs expression relates to study on cells maintained in standard oxygen condition of 21%, while the emerging evidence suggests that culturing cells in ambient air is far from physiological. In fact, oxygen in human tissues ranges from 1 to 11%. The aim of this study was to compare the effects of physiological lymph node normoxia (5% O2), and hyperoxia (21% O2) on the expression of cellular adhesion molecules of primary diffuse large B-cell lymphoma cells (DLBCL) isolated from 10 lymphoma patients. Quantitative RT-PCR and immunohistochemistry were used to confirm the differential expression of several CAMs, including ICAM, CD83, CD81, CD44, depending on the level of oxygen. Our findings also suggest that DLBCL cells maintained at ambient O2 (21%) exhibit reduced growth rate and migration ability compared to the cells growing in normoxia conditions. Taking into account all the observations, we emphasize the need to identify the optimal human cell culture conditions mimicking the physiological aspects of tumor growth and differentiation.

Keywords: adhesion molecules, diffuse large B-cell lymphoma, physiological normoxia, quantitative RT-PCR

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Authors: Yoonah Lee, Richard Kyung

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With technological advances in the computational biomedical field, the ability to measure neurotransmitters’ chemical imbalances that affect depression and anxiety has been established. By comparing the thermodynamics stability of amino acid supplements, such as glutamine, tyrosine, phe-nylalanine, and methionine, this research analyzes mood-regulating neurotransmitters, amino acid supplements, and antipsychotic substances (ie. Reserpine molecule and CRF complexes) in relation to depression and anxiety and suggests alternative complexes that are low in energy to act as more efficient treatments for mood disorders. To determine a molecule’s thermodynamic stability, this research examines the molecular energy using Avogadro, a software for building virtual molecules and calculating optimized geometry using GAFF (General Amber Force Field) and UFF (Universal Force Field). The molecules, built using Avogadro, is analyzed using their theoretical values and atomic properties.

Keywords: amino acids, anxiety, depression, neurotransmitters

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Authors: Asli Beyler Çi̇ği̇l, Memet Vezi̇r Kahraman

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Organic–inorganic hybrids have become an effective source of advanced materials because they combine the advantages of both the organic moiety such as flexibility, low dielectric constant, and processability, and inorganic moiety as rigidity, strength, durability, and thermal stability. By incorporating cross-linkable side chains, the hybrid materials can be made photosensitive and UV curable, which offers many advantages including low processing temperature, low equipment cost and compatibility. In this study, uv-curable organic-inorganic hybrid material, which was contained surface modified polyaniline particles (PANI), was prepared. PANI surface photografted with hydroxy ethyl methacrylate (HEMA) to produce hydroxyl groups. Hydroxyl functionalized PANI/HEMA was acrylated using isocyanato ethyl methacrylate (IEM) in order to improve the dispersion and interfacial interaction in composites. UV-curable formulation was prepared by mixing the surface modified PANI, polyethylene glycol diacrylate (PEGDA), trimethylolpropane triacrylate (TMPTA), hydrolized 3- methacryloxypropyltrimethoxysilane (hyd. MEMO) and photoinitiator. Chemical structure of nano-hybrid material was characterized by FTIR. FTIR spectra showed that the photografting of PANI was prepared successfully. Thermal properties of the nano-hybrid material were determined by thermogravimetric analysis (TGA). The morphology of the nano-hybrid material was performed by scanning electron microscopy (SEM).

Keywords: polyaniline, photograft, sol-gel, uv-curable polymer

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Authors: Wei-Hsuan Hsu, Yi-Xuan Huang

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Nanoimprint lithography (NIL) possesses the advantages of sub-10-nm feature and low cost. NIL patterns the resist with physical deformation using a mold, which can easily reproduce the required nano-scale pattern. However, the variation of process parameters and environmental conditions seriously affect reproduction quality. How to ensure the quality of imprinted pattern is essential for industry. In this study, the authors used the electrowetting technology to assist mold filling in the NIL process. A special mold structure was designed to cause electrowetting. During the imprinting process, when a voltage was applied between the mold and substrate, the hydrophilicity/hydrophobicity of the surface of the mold can be converted. Both simulation and experiment confirmed that the electrowetting technology can assist mold filling and avoid incomplete filling rate. The proposed method can also reduce the crack formation during the de-molding process. Therefore, electrowetting technology can improve the process quality of NIL.

Keywords: electrowetting, mold filling, nano-imprint, surface modification

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Authors: Benchouala Amira, Bojic Clement, Poupin Pascal, Cossu Leguille-carole

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The objective of this study is to evaluate in vitro the cytotoxic and androgenic potential of several antifungal molecules (amphotericin B, econazole, ketoconazole and miconazole) on MDA-Kb2 cell lines. This biological model is an effective tool for the detection of endocrine disruptors because it responds well to the main agonist of the androgen receptor (testosterone) and also to an antagonist: flutamide. The cytotoxicity of each chemical compound tested was measured using an MTT assay (tetrazolium salt, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) which measures the activity of the reductase function of mitochondrial succinate dehydrogenase enzymes of cultured cells. This complementary cytotoxicity test is essential to ensure that the effects of reduction in luminescence intensity observed during androgenic tests are only attributable to the anti-androgenic action of the compounds tested and not to their possible cytotoxic properties. Tests of the androgenic activity of antifungals show that these compounds do not have the capacity to induce transcription of the luciferase gene. These compounds do not exert an androgenic effect on MDA-Kb2 cells in culture for the environmental concentrations tested. The addition of flutamide for the same tested concentrations of antifungal molecules reduces the luminescence induced by amphotericin B, econazole and miconazole, which is explained by a strong interaction of these molecules with flutamide which may have a greater toxic effect than when tested alone. The cytotoxicity test shows that econazole and ketoconazole can cause cell death at certain concentrations tested. This cell mortality is perhaps induced by a direct or indirect action on deoxyribonucleic acid (DNA), ribonucleic acid (RNA) or proteins necessary for cell division.

Keywords: cytotoxicity, androgenic potential, antifungals, MDA-Kb2

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Authors: N. Bouzouita, A. Snoussi , H. Ben Haj Koubaier, I. Essaidi, M. M. Chaabouni, S. Zgoulli, P. Thonart

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Color is one of the most important quality attributes for the food industry. Grape marc, a complex lignocellulosic material is one of the most abundant and worth less byproduct, generated after the pressing process. The development of the process of purification by micro filtration, ultra filtration, nano filtration and drying by atomization of the anthocyanins of Tunisian origin is the aim of this work. Locust bean gum is the ground endosperm of the seeds of carob fruit; owing to its remarkable water-binding properties, it is widely used to improve the texture of food and largely employed in food industry. The purification of LGB causes drastically reduced ash and proteins contents but important increase for galactomannan.

Keywords: Carob, food additives, grape pomace, locust bean gum, natural colorant, nano filtration, thickener, ultra filtration

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Authors: Dhuha Albusalih, David Weston, Simon Gill

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Nanocomposites Co-SiC with well dispersed nanoparticles and Co nano grain size has produced using Pulse Reverse Plating (PRP) and using anionic surfactant. Different particle contents of nanocomposites were produced by altering the plating parameters. The method allows great control over the level of nanoparticles in the coating, without changing bath chemistry. Examination by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), TEM and X-Ray Diffraction (XRD) analysis was performed to characterize and study the strengthening mechanisms of these nanocomposites. The primary strengthening mechanisms were shown to be grain refinement and dispersion strengthening. Tribological performances of the produced electroplated nanocomposite Co-SiC coatings were examined. Results showed that the coating with the higher volume fraction (vol. %) of SiC and the smallest grain size has the higher hardness and low wear rate.

Keywords: nanocomposites, pulse reverse plating, tribological performance of cobalt nanocomposites

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Authors: Elham Shakerian, Reza Afarin

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The hepatic disease causes approximately 2 million deaths/year worldwide. Liver fibrosis is the last stage of numerous chronic liver diseases, and until now there is no definite cure or drug for it. Activation of hepatic stellate cells (HSCs) is the main reason for fibrosis. Transforming growth factor (TGF-β), as a main profibrogenic cytokine, if increased in these cells, leads to liver fibrosis through smad3 signaling pathways and increasing the expressions of Collagen type I and III, and actin-alpha smooth muscle (αSMA) genes. Curcumin (CUR) is a polyphenolic compound and an active ingredient derived from the rhizome of the turmeric plant that exerts effective antioxidant, anti-inflammatory, and antimicrobial activity. It has been shown that daily consumption of curcumin may have a protective effect on the liver against oxidative stress associated with alcohol consumption. In this study, we investigate the role of Curcumin in decreasing HSC activation and treating liver fibrosis. First, the human HSCs were treated with 2 ng/ml of (TGF-β) for 24 hours to become activated, then with Silibinin for 24 hours. Total RNAs were extracted, reversely transcribed into cDNA, Quantitative Real-time PCR, and western blot were performed. The mRNA expression levels of Collagen type I and III, αSMA genes, and the level of smad3 phosphorylation in TGF-β activated human HSCs treated with Curcumin were significantly reduced compared to human HSCs untreated with Curcumin. Curcumin is effective in reducing the expression of fibrogenic genes in the activated human HSCs treated with TGFB through downregulation of the TGF-β/smad3 signaling pathway. Therefore, Curcumin possesses significant antifibrotic properties in hepatic fibrosis

Keywords: hepatic fibrosis, human HSCs, curcumin, fibrogenic genes

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Authors: Kai-Fen Tu, Jenn-Wen Huang, Yao-Tung Lin

Abstract:

Cucumber is a major economic crop in the world. The global production of cucumber in 2017 was more than 71 million tonnes. Nonetheless, downy mildew, caused by Pseudoperonospora cubensis, is a devastating and common disease on cucumber in around 80 countries and causes severe economic losses. The long-term usage of fungicide also leads to the occurrence of fungicide resistance and decreases host resistance. In this study, six types of oil (neem oil, moringa oil, soybean oil, cinnamon oil, clove oil, and camellia oil) were selected to synthesize micro/nano-sized emulsions, and the disease control efficacy of micro/nano-sized emulsions were evaluated. Moreover, oil concentrations (0.125% - 1%) and droplet size of emulsion were studied. Results showed cinnamon-type emulsion had the best efficacy among these oils. The disease control efficacy of these emulsions increased as the oil concentration increased. Both disease incidence and disease severity were measured by detached leaf and pot experiment, respectively. For the droplet size effect, results showed that the 114 nm of droplet size synthesized by 0.25% cinnamon oil emulsion had the lowest disease incidence (6.67%) and lowest disease severity (33.33%). The release of zoospore was inhibited (5.33%), and the sporangia germination was damaged. These results suggest that cinnamon oil emulsion will be a valuable and environmentally friendly alternative to control cucumber downy mildew. The economic loss caused by plant disease could also be reduced.

Keywords: downy mildew, emulsion, oil droplet size, plant protectant

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Authors: Jun Yang, Ching-Liang Hsieh, Yi-Wen Lin

Abstract:

Chronic inflammatory pain results from peripheral tissue injury or local inflammation to increase the release of protons, histamines, adenosine triphosphate, and several proinflammatory cytokines. Transient receptor potential vanilloid 1 (TRPV1) is involved in fibromyalgia, neuropathic, and inflammatory pain; however, its exact mechanisms in chronic inflammatory pain are still unclear. We investigate the analgesic effect of EA by injecting complete Freund’s adjuvant (CFA) in the hind paw of mice to induce chronic inflammatory pain ( > 14 d). Our results showed that EA significantly reduced chronic mechanical and thermal hyperalgesia in the chronic inflammatory pain model. Chronic mechanical and thermal hyperalgesia was also abolished in TRPV1−/− mice. TRPV1 increased in the dorsal root ganglion (DRG) and spinal cord (SC) at 2 weeks after CFA injection. The expression levels of downstream molecules such as pPKA, pPI3K, and pPKC increased, as did those of pERK, pp38, and pJNK. Transcription factors (pCREB and pNFκB) and nociceptive ion channels (Nav1.7 and Nav1.8) were involved in this process. Inflammatory mediators such as GFAP (Glial fibrillary acidic protein), S100B, and RAGE (Receptor for advanced glycation endproducts) were also involved. The expression levels of these molecules were reduced in EA (electroacupuncture) and TRPV1−/−mice but not in the sham EA group. The present study demonstrated that EA or TRPV1 gene deletion reduced chronic inflammatory pain through TRPV1 and related molecules. In addition, our data provided evidence to support the clinical use of EA for treating chronic inflammatory pain.

Keywords: auricular electric-stimulation, epileptic seizures, anti-inflammation, electroacupuncture

Procedia PDF Downloads 174

Authors: Lia Gventsadze, Elguja Kutelia, David Gventsadze

Abstract:

The purpose of the article is to show the possibility for the development of a new generation, eco-friendly (asbestos free) nano-porous friction materials on the basis of Georgian raw materials, along with the determination of technological parameters for their production, as well as the optimization of tribological properties and the investigation of structural aspects of wear peculiarities of elaborated materials using the scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) methods. The study investigated the tribological properties of the polymer friction materials on the basis of the phenol-formaldehyde resin using the porous diatomite filler modified by silane with the aim to improve the thermal stability, while the composition was modified by iron phosphate, technical carbon and basalt fibre. As a result of testing the stable values of friction factor (0.3-0,45) were reached, both in dry and wet friction conditions, the friction working parameters (friction factor and wear stability) remained stable up to 500 OC temperatures, the wear stability of gray cast-iron disk increased 3-4 times, the soundless operation of materials without squeaking were achieved. Herewith it was proved that small amount of ingredients (5-6) are enough to compose the nano-porous friction materials. The study explains the mechanism of the action of nano-porous composition base brake lining materials and its tribological efficiency on the basis of the triple phase model of the tribo-pair.

Keywords: brake lining, friction coefficient, wear, nanoporous composite, phenolic resin

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Authors: Esma Kocaoglu, Oktay Talaz, Huseyin Cavdar, Murat Senturk, Deniz Eki̇nci̇

Abstract:

Glutathione reductase (GR) is a crucial antioxidant enzyme which is responsible for the maintenance of the antioxidant GSH (glutathione) molecule. Antimalarial effects of some chemical molecules are attributed to their inhibition of GR; thus inhibitors of this enzyme are expected to be promising candidates for the treatment of malaria. In this work, GR inhibitory properties of N-Methylpyrrole derivatives are reported. Firstly, GR was purified by means of affinity chromatography using 2’,5’-ADP-Sepharose 4B as ligand. Enzymatic activity was measured by Beutler’s method. Synthesis of the compounds was approved by thin layer chromatography and column chromatography. Different inhibitor concentrations were used and all compounds were tested in triplicate at each concentration used. It was found that all compounds have better inhibitory activity than the strong GR inhibitor N,N-bis(2-chloroethyl)-N-nitrosourea, especially three molecules, 8m, 8n, and 8q, are the best among them with low micromolar I₅₀ values. Findings of our study indicate that these Schiff base derivatives are strong GR inhibitors which can be used as leads for designation of novel antimalaria candidates.

Keywords: glutathione reductase, antimalaria, inhibitor, enzyme

Procedia PDF Downloads 268

Authors: Khaoula Hidouri, Ali Benhmidene, Bechir Chouachi, Dhananjay R. Mishra, Ammar Houas

Abstract:

Activated carbon DSAC36-24 iy is adsorbent materials, characterized by a specific surface area of 548.13 m²g⁻¹. Their manufacture uses the natural raw materials like the nucleus of dates. In this study the treatment is done in two stages: A chemical treatment by H₃PO₄ followed by a physical treatment under nitrogen for 1 hour then under stream of CO₂ for 24 hours. A characterization of the various parameters was determined such as the measurement of the specific surface area, determination of pHPZC, bulk density, iodine value. The study of the adsorption of organic molecules (hydroquinone, paranitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol) indicates that the adsorption phenomena are essentially due to the van der Waals interaction. In the case of organic molecules carrying the polar substituents, the existence of hydrogen bonds is also proved by the donor-acceptor forces. The study of the pH effect was done with modeling by different models (Langmuir, Freundlich, Langmuir-Freundlich, Redlich-Peterson), a kinetic treatment is also followed by the application of Lagergren, Weber, Macky.

Keywords: adsoprtion ishoterms, adsorption kinetics, DSAC36-24, organic molecule

Procedia PDF Downloads 278