Search results for: in vitro biofilm formation

Authors: Tuba Kizilirmak

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Distinct properties of porous metamaterials have been largely processed for biomedicine requiring a three-dimensional (3D) porous structure engaged with fine mechanical features, biodegradation ability, and biocompatibility. Applications of metamaterials are (i) porous orthopedic and dental implants; (ii) in vitro cell culture of metamaterials and bone regeneration of metamaterials in vivo; (iii) macro-, micro, and nano-level porous metamaterials for sensors, diagnosis, and drug delivery. There are some specific properties to design metamaterials for tissue engineering. These are surface to volume ratio, pore size, and interconnection degrees are selected to control cell behavior and bone ingrowth. In this study, additive manufacturing technique selective laser melting will be used to print the scaffolds. Selective Laser Melting prints the 3D components according to designed 3D CAD models and manufactured materials, adding layers progressively by layer. This study aims to design metamaterials with Ti6Al4V material, which gives benefit in respect of mechanical and biological properties. Ti6Al4V scaffolds will support cell attachment by conferring a suitable area for cell adhesion. This study will control the osteoblast cell attachment on Ti6Al4V scaffolds after the determination of optimum stiffness and other mechanical properties which are close to mechanical properties of bone. Before we produce the samples, we will use a modeling technique to simulate the mechanical behavior of samples. These samples include different lattice models with varying amounts of porosity and density.

Keywords: additive manufacturing, titanium lattices, metamaterials, porous metals

Procedia PDF Downloads 186

Authors: Serap Pektas

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Ataxia telangiectasia mutated (ATM) is a serine-threonine kinase, which is the major regulator of the DNA damage response. ATM is activated upon the formation of DNA double-strand breaks (DSBs) in the cells. ATM phosphorylates the proteins involved in apoptotic responses, cell cycle checkpoint control, DNA repair, etc. Tumor protein p53, known as p53 is one of these proteins that phosphorylated by ATM. Phosphorylation of p53 at Ser15 residue leads to p53 stabilization in the cells. Often enzymes activity is affected by hydrogen ion concentration (pH). In order to find the optimal pH range for ATM activity, steady-state kinetic assays were performed at acidic and basic pH ranges. Ser15 phosphorylation of p53 is determined by using ELISA. The results indicated that the phosphorylation rate was better at basic pH range compared with the acidic pH range. This could be due to enzyme stability, or enzyme-substrate interaction is pH dependent.

Keywords: ataxia telangiectasia mutated, DNA double strand breaks, DNA repair, tumor protein p53

Procedia PDF Downloads 120

Authors: Tarek S. Jamil, H. A. Abbas, Rabab A. Nasr, Eman S. Mansor, Rose-Noëlle Vannier

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The citrate manner (Pechini method) was utilized in elaboration of a novel Nano-sized BaFe(1-x)CuxO3 (x=0.01, 0.05 and 0.10). The prepared photocatalysts were characterized by x-ray diffraction, diffuse reflectance, TEM and the surface area. The prepared samples have a mixture of cubic perovskite structure (main) and orthorhombic phases. The effect of different loads of copper as dopant on the structural properties as well as the photocatalytic activity was demonstrated. The lattice parameter and the unit cell volume of the prepared materials are given. Doping with copper increased the photocatalytic activity of BaFeO3 several times in abstraction of hazardous atrazine that causes acute problems in drinking water treatment facilities. This may be reasoned to low band gap energy of copper doped BaFe(1-x)CuxO3 attributed to oxygen vacancies formation.

Keywords: photocatalysis, nano-sized, BaFeO3, copper doping, atrazine

Procedia PDF Downloads 343

Authors: Ying-Chieh Lee, Huei-Jyun Shih, Ting-Yang Wang, Christian Pithan

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This study focuses on the synthesis and characterization of Ca₀.₆Sr₀.₄₋ₓBaₓZrO₃ (x = 0.01, 0.04, 0.07, and 0.10) ceramics prepared via the solid-state method and sintered at 1450 °C. The impact of Sr substitution by Ba at the A-site of the perovskite structure on crystalline properties and microwave dielectric performance was investigated. The experimental results show the formation of a single-phase structure, Ca₀.₆₁₂Sr₀.₃₈₈ZrO₃(CSZ), across the entire range of x values. It is evident that the Ca₀.₆Sr₀.₃₉Ba₀.₀₁ZrO₃ ceramics exhibit the highest sintering density and the lowest porosity. These ceramics exhibit impressive dielectric properties, including a high permittivity of 28.38, low dielectric loss of 4.0×10⁻⁴, and a Q factor value of 22988 at 9~10GHz. The research reveals that the influences of Sr substitution by Ba in enhancing the microwave dielectric properties of Ca₀.₆₁₂Sr₀.₃₈₈ZrO₃ ceramics and the impedance curves clearly showed effects on the electrical properties.

Keywords: NPO dielectric material, (Ca₀.₆Sr₀.₄)ZrO₃, microwave dielectric properties

Procedia PDF Downloads 51

Authors: Jose A. Aznar-Moreno, Xi Jiang, Stefan Burén, Luis M. Rubio

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Integration of prokaryotic nitrogen fixation (nif) genes into the plastid genome for expression of functional nitrogenase components could render plants capable of assimilating atmospheric N2 making their crops less dependent of nitrogen fertilizers. The nitrogenase Fe protein component (NifH) has been used as proxy for expression and targeting of Nif proteins within plant and yeast cells. Here we use tobacco plants with the Azotobacter vinelandii nifH and nifM genes integrated into the plastid genome. NifH and its maturase NifM were constitutively produced in leaves, but not roots, during light and dark periods. Nif protein expression in transplastomic plants was stable throughout development. Chloroplast NifH was soluble, but it only showed in vitro activity when isolated from leaves collected at the end of the dark period. Exposing the plant extracts to elevated temperatures precipitated NifM and apo-NifH protein devoid of [Fe4S4] clusters, dramatically increasing the specific activity of remaining NifH protein. Our data indicate that the chloroplast endogenous [Fe-S] cluster biosynthesis was insufficient for complete NifH maturation, albeit a negative effect on NifH maturation due to excess NifM in the chloroplast cannot be excluded. NifH and NifM constitutive expression in transplastomic plants did not affect any of the following traits: seed size, germination time, germination ratio, seedling growth, emergence of the cotyledon and first leaves, chlorophyll content and plant height throughout development.

Keywords: NifH, chloroplast, nitrogen fixation, crop improvement, transplastomic plants, fertilizer, biotechnology

Procedia PDF Downloads 146

Authors: O. M. M. Sabry, Abeer M. El Sayed

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The essential oils from the aerial parts and flowers of Haplophyllum tuberculatum (Forsskal) Adr. Juss (Rutaceae) growing in Libya were obtained separately by hydro-distillation using a Clevenger-type apparatus. The essential oils yield were (0.4, 1.5w/w%) respectively based on the dry weight of the plant. The oils were analyzed by GC-MS. Twenty four constituents, amounting to 96.6%, were identified in the oil of the aerial parts. The predominant compounds were among the non oxygenated terpenoids (82.4%) as monoterpene hydrocarbons, represented by sabinen (26.4 %), δ-terpinen (26 %), β-phellandrene (10.4%) and 3-carene (3.86%). Zingiberine (0.4%) and β-sesquiphellandrene (0.12%) were the major sesquiterpene hydrocarbons identified. Oxygenated monoterpenes were represented by eucalyptol (5.5%) and piperitone (5.55%). Twenty six constituents, equivalent to 99.5%, were identified in the oil of the flowers. The dominance of monoterpene hydrocarbons in the flowers oil can be attributed to the high percentage of γ-terpinen (38.44%), β-phellandrene (10.0%), α- phellandrene (2.33%), 3,4-dimethyl-1,5-cyclooctadiene (6.67%), β-myrecene (6.04%), 3-carene (5.43%) and α-pinene (1.3%).While the oxygenated monoterpenes can be contributed to the trans-piperitol (4.67%) and piperitone (2.07%). Sesquiterpene hydrocarbons were not identified in the oil of the flower of H. tuberculatum. Variation in constitution between oils of Libyan H. tuberculatum and that obtained from other countries can be due to both environmental and genetic factors. The essential oils have demonstrated variable antimicrobial activities against certain micro-organisms. Also have revealed marked in vitro cytotoxicity against lung (H1299), liver (HEPG2) carcinoma cell line and variably effective as anti-inflammatory and antioxidant.

Keywords: Halpophyllum tuberculatum, rutaceae, essential oil, antimicrobial, anti-inflammatory, antitumor, antioxidant, Libya

Procedia PDF Downloads 469

Authors: Rahul Madathiparambil Visalakshan, Alex Cavallaro, John Hayball, Krasimir Vasilev

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The role of biomaterial surface nanotopograhy on fibrinogen adsorption and unfolding, and the subsequent immune response were studied. Inconsistent topography and varying chemical functionalities along with a lack of reproducibility pose a challenge in determining the specific effects of nanotopography or chemistry on proteins and cells. It is important to have a well-defined nanotopography with a homogeneous chemistry to study the real effect of nanotopography on biological systems. Therefore, we developed a technique that can produce well-defined and highly reproducible topography to identify the role of specific roughness, size, height and density with the presence of homogeneous chemical functionality. Using plasma polymerisation of oxazoline monomers and immobilized gold nanoparticles we created surfaces with an equal number density of nanoparticles of different sizes. This surface was used to study the role of surface nanotopography and the interplay of surface chemistry on proteins and immune cells. The effect of nanotopography on fibrinogen adsorption was investigated using Quartz Cristal Microbalance with Dissipation and micro BCA. The mass of fibrinogen adsorbed on the surface increased with increasing size of nano-topography. Protein structural changes up on adsorption to the nano rough surface was studied using circular dichroism spectroscopy. Fibrinogen unfolding varied depending on the specific nanotopography of the surfaces. It was revealed that the in vitro immune response to the nanotopography surfaces changed due to this protein unfolding.

Keywords: biomaterial inflammation, protein and cell responses, protein unfolding, surface nanotopography

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Authors: Y. C. Khoo, W. T. Lai

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The single orifice hydraulic flat spray nozzle was evaluated with two global imaging techniques to characterize various aspects of the resulting spray. The two techniques were high resolution flow visualization and Particle Image Velocimetry (PIV). A CCD camera with 29 million pixels was used to capture shadowgraph images to realize ligament formation and collapse as well as droplet interaction. Quantitative analysis was performed to give the sizing information of the droplets and ligaments. This camera was then applied with a PIV system to evaluate the overall velocity field of the spray, from nozzle exit to droplet discharge. PIV images were further post-processed to determine the inclusion angle of the spray. The results from those investigations provided significant quantitative understanding of the spray structure. Based on the quantitative results, detailed understanding of the spray behavior was achieved.

Keywords: spray, flow visualization, PIV, shadowgraph, quantitative sizing, velocity field

Procedia PDF Downloads 371

Authors: Illyas Isa, Siti Nur Akmar Mohd Yazid, Norhayati Hashim

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We report a simple, green and cost effective synthesis of graphene via chemical reduction of graphene oxide in alkaline aqueous solution. Extensive characterizations have been studied to confirm the formation of graphene in sodium carbonate solution. Cyclic voltammetry was used to study the electrochemical properties of the prepared graphene-modified glassy carbon electrode using potassium ferricyanide as a redox probe. Based on the result, with the addition of graphene to the glassy carbon electrode the current flow increases and the peak also broadens as compared to graphite and graphene oxide. This method is fast, cost effective, and green as nontoxic solvents are used which will not result in contamination of the products. Thus, this method can serve for the preparation of graphene which can be effectively used in sensors, electronic devices and supercapacitors.

Keywords: chemical reduction, electrochemical, graphene, green synthesis

Procedia PDF Downloads 323

Authors: Sameh M. Osman, El-Refaie Kenawy, Zeid A. Al-Othman, Mohamed H. El-Newehy, El-Saied A. Aly, Sherine N. Khattab, Ayman El-Faham

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Recently, there has been a huge interest in using cyanuric chloride in a wide range of functional group transformations, as Cyanuric chloride has temperature-dependent differential reactivity for displacement of chlorides with various nucleophiles In the present work, some copolymers based on s-triazine Unit were prepared by microwave-assisted synthesis. For comparison study, the copolymers were synthesized by the conventional method. Synthesized Copolymers were characterized by MP, IR, TGA, DSC and GPC. The result indicated that copolymers are thermally stable and in good in composition and yield. Further studies that involve the test for selected removal of transition elements such as Cu (II), Zn (II) and Mn (II). Moreover, the effects of the polymeric triazine derivatives containing different functional groups which expected to have a good thermal stability and char formation ability on thermal degradation and flame retardancy.

Keywords: flame retardants, heavy metals, microwave-assisted synthesis, s-triazine

Procedia PDF Downloads 347

Authors: Kriyapa lairungruang, Arunporn Itharat

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Limonia acidissima L. (LA) (Common name: wood apple, Thai name: ma-khwit) is a medicinal plant which has long been used in Thai traditional medicine. Its bark is used for treatment of diarrhea, abscess, wound healing and inflammation and it is also used in oral cancer. Thus, this research aimed to investigate antioxidant and cytotoxic activities of the LA bark extracts produced by various extraction methods. Different extraction procedures were used to extract LA bark for biological activity testing: boiling in water, maceration with 95% ethanol, maceration with 50% ethanol and water boiling of each the 95% and the 50% ethanolic residues. All extracts were tested for antioxidant activity using DPPH radical scavenging assay, cytotoxic activity against human laryngeal epidermoid carcinoma (HEp-2) cells and human oral epidermoid carcinoma (KB) cells using sulforhodamine B (SRB) assay. The results found that the 95% ethanolic extract of LA bark showed the highest antioxidant activity with EC50 values of 29.76±1.88 µg/ml. For cytotoxic activity, the 50% ethanolic extract showed the best cytotoxic activity against HEp-2 and KB cells with IC50 values of 9.55±1.68 and 18.90±0.86 µg/ml, respectively. This study demonstrated that the 95% ethanolic extract of LA bark showed moderate antioxidant activity and the 50% ethanolic extract provided potent cytotoxic activity against HEp-2 and KB cells. These results confirm the traditional use of LA for the treatment of oral cancer and laryngeal cancer, and also support its ongoing use.

Keywords: antioxidant activity, cytotoxic activity, Laryngeal epidermoid carcinoma, Limonia acidissima L., oral epidermoid carcinoma

Procedia PDF Downloads 471

Authors: F. Adjel, S. Almi, D. Barkat

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The synergistic solvent extraction of nickel ion from 0.33 mol dm^-3 Na2SO4 aqueous solutions with capric acid (HL) in the absence and presence of Tri-n-octylphosphine oxide (TOPO) in chloroform at 25°C, has been studied. The extracted species when the capric acid compound was used alone, is NiL2 and NiL2(HL). In the presence of TOPO, a remarkable enhancement on the extraction of nickel (II) with 0.02 mol dm^-3 capric acid was observed upon the addition of 0.00125 and 0.0025 mol dm^-3 TOPO in chloroform. From a synergistic extraction- equilibrium study, the synergistic enhancement was ascribed to the adduct formation NiL2(TOPO) and NiL2(HL)(TOPO). The TOPO-HL interaction strongly influences the synergistic extraction efficiency. The synergistic extraction stoichiometry of nickel (II) with capric acid and TOPO is studied with the methods of slope analysis. The equilibrium constants were determined.

Keywords: solvent extraction, nickel(II), capric acid, TOPO, synergism

Procedia PDF Downloads 586

Authors: Nagi Greesh

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This study highlights a new method to obtain multiphase composites particles containing hydrophobic (wax) and inorganic (clay) compounds. Multiphase polystyrene-clay-wax nanocomposites were successfully synthesized. Styrene monomer were polymerized in the presence of different wax-clay nanocomposites concentrations in miniemulsion. Wax-clay nanocomposites were firstly obtained through ultrasonic mixing at a temperature above the melting point of the wax at different clay loadings. The obtained wax-clay nanocomposites were then used as filler in the preparation of polystyrene-wax-clay nanocomposites via miniemulsion polymerization. The particles morphology of PS/wax-clay nanocomposites latexes was mainly determined by Transmission Electron Microscopy ( TEM) , core/shell morphology was clearly observed, with the encapsulation of most wax-clay nanocomposites inside the PS particles. On the other hand, the morphology of the PS/wax-clay nanocomposites (after film formation) ranged from exfoliated to intercalated structures, depending on the percentage of wax-clay nanocomposites loading. This strategy will allow the preparation materials with tailored properties for specific applications such as paint coatings and adhesives.

Keywords: polymer-wax, paraffin wax, miniemulsion, core/shell, nanocomposites

Procedia PDF Downloads 81

Authors: Mustafa Ümi̇t Ünal, Nafi̇z Çeli̇ktaş, Aysun Şener, Sara Betül Dolgun, Duygu Keser

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The aim of this study was to compare acid and base pretreatment of switchgrass for bioethanol production. Switchgrass was pretreated with sulfuric acid and sodium hydroxide at 0.5, 1.0 and 1.5% (v/v) at 120, 140, 180 °C for 10, 60 and 90. Optimization of enzymatic hydrolysis of the pretreated switchgrass samples were carried out using three different enzyme mixtures (22.5 mg cellulase and 75 mg cellobiase /g biomass; 45 mg cellulase and 150 mg cellobiase /g biomass; 90 mg cellulase and 300 mg cellobiase /g biomass). Samples were removed at 24-h interval for fermentable sugar analyses with HPLC. The results showed that use of 90 mg cellulase and 300 mg cellobiase/g biomass resulted in the highest fermentable sugar formation. Furthermore, the highest fermentable sugar yield was obtained by pretreatment at 120 °C for 10 min using 1.0 % sodium hydroxide.

Keywords: switchgrass, acid pretreatment, enzymatic hydrolysis, base pretreatment, ethanol production

Procedia PDF Downloads 513

Authors: Fereshteh Chekin, Sepideh Sadeghi

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Nickel nanoparticles have attracted much attention because of applications in catalysis, medical diagnostics and magnetic applications. In this work, we reported a simple and low-cost procedure to synthesize nickel oxide nanoparticles (NiO-NPs) by using sodium dodecyl sulphate (SDS) and gelatin as stabilizer. The synthesized NiO-NPs were characterized by a variety of means such as transmission electron microscope (TEM), powder X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-vis spectroscopy. The results show that the NiO nanoparticles with high crystalline can be obtained using this simple method. The grain size measured by TEM was 16 in presence of SDS, which agrees well with the XRD data. SDS plays an important role in the formation of the NiO nanoparticles. Moreover, the NiO nanoparticles have been used as a solid phase catalyst for the decomposition of hydrazine hydrate at room temperatures. The decomposition process has been monitored by UV–vis analysis. The present study showed that nanoparticles are not poisoned after their repeated use in decomposition of hydrazine.

Keywords: nickel oxide nanoparticles, sodium dodecyl sulphate, synthesis, stabilizer

Procedia PDF Downloads 474

Authors: Y. H. Hwang, J. Won, Y. S. Kang

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Since ionic liquids have a special interaction with gas specially CO2 and/or olefin, supported ionic liquids membrane (SILM) are fabricated for practical gas separation. However, SILM has a problem in practical application due to the low mechanical stability under high pressure for gas separation. In order to improve the mechanical strength of the selective ionic liquid layer, we prepared supported ion gel membrane by the formation of gel on the surface of Nylon support. The ion gel was prepared by the addition of poly(styrene-block-ethyleneoxide-block-styrene) triblock copolymer in four tricyanomethanide ionic liquids have different cation; 1-ethyl-3-methlyimidazolium tricyanomethanide, 1-butyl-3-methlyimidazolium tricyanomethanide, 1-butyl-1-methylpyrrolidinium tricyanomethanide, 1-butyl-4-methylpyridinium tricyanomethanide using methylenechloride as a solvent. The characters of ion gel with different cation were studied. Four different gases (CO2, N2, O2, and CH4) permeance were measured at room temperature by bubble flow meter and cation effect of tricyanomethanide ionic liquids investigated.

Keywords: membrane, ionic liquid, ion gel, nanostructure

Procedia PDF Downloads 336

Authors: Caroline M. B. De Araujo, Helenise A. Do Nascimento, Claudia J. Da S. Cavalcanti, Mauricio A. Da Motta Sobrinho, Maria F. Pimentel

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Oil production is often followed by the joint production of water and gas. During the journey up to the surface, due to severe conditions of temperature and pressure, the mixing between these three components normally occurs. Thus, the three phases separation process must be one of the first steps to be performed after crude oil extraction, where the water-oil separation is the most complex and important step, since the presence of water into the process line can increase corrosion and hydrates formation. A wide range of methods can be applied in order to proceed with oil-water separation, being more commonly used: flotation, hydrocyclones, as well as the three phase separator vessels. Facing what has been presented so far, it is the aim of this paper to study a system consisting of a three-phase separator, evaluating the influence of three variables: temperature, working pressure and separator type, for two types of oil (light and heavy), by performing two factorial design plans 23, in order to find the best operating condition. In this case, the purpose is to obtain the greatest oil flow rate in the product stream (m3/h) as well as the lowest percentage of water in the oil stream. The simulation of the three-phase separator was performed using Aspen Hysys®2006 simulation software in stationary mode, and the evaluation of the factorial experimental designs was performed using the software Statistica®. From the general analysis of the four normal probability plots of effects obtained, it was observed that interaction effects of two and three factors did not show statistical significance at 95% confidence, since all the values were very close to zero. Similarly, the main effect "separator type" did not show significant statistical influence in any situation. As in this case, it has been assumed that the volumetric flow of water, oil and gas were equal in the inlet stream, the effect separator type, in fact, may not be significant for the proposed system. Nevertheless, the main effect “temperature” was significant for both responses (oil flow rate and mass fraction of water in the oil stream), considering both light and heavy oil, so that the best operation condition occurs with the temperature at its lowest level (30oC), since the higher the temperature, the liquid oil components pass into the vapor phase, going to the gas stream. Furthermore, the higher the temperature, the higher the formation water vapor, so that ends up going into the lighter stream (oil stream), making the separation process more difficult. Regarding the “working pressure”, this effect showed to be significant only for the oil flow rate, so that the best operation condition occurs with the pressure at its highest level (9bar), since a higher operating pressure, in this case, indicated a lower pressure drop inside the vessel, generating lower level of turbulence inside the separator. In conclusion, the best-operating condition obtained for the proposed system, at the studied range, occurs for temperature is at its lowest level and the working pressure is at its highest level.

Keywords: factorial experimental design, oil production, simulation, three-phase separator

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Authors: Aleš Florian, Lenka Ševelová, Jaroslav Žák

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Formation of tensile cracks in concrete slabs of rigid pavement can be (among others) the initiation point of the other, more serious failures which can ultimately lead to complete degradation of the concrete slab and thus the whole pavement. Two measures can be used for reliability assessment of this phenomenon - the probability of failure and/or the reliability index. Different methods can be used for their calculation. The simple ones are called moment methods and simulation techniques. Two methods - FOSM Method and Simple Random Sampling Method - are verified and their comparison is performed. The influence of information about the probability distribution and the statistical parameters of input variables as well as of the limit state function on the calculated reliability index and failure probability are studied in three points on the lower surface of concrete slabs of the older type of rigid pavement formerly used in the Czech Republic.

Keywords: failure, pavement, probability, reliability index, simulation, tensile crack

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Authors: Natalya G. Filimonova, Mariya G. Ozerova, Irina N. Ermakova

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The long-term strategy of the economic development of Russia up to 2030 is based on the concept of sustainable growth. The determining factor of such development is complex changes in the economic system which may be achieved by making progressive changes in its structure. The structural changes determine the character and the direction of economic development, as well as they include all elements of this system without exception, and their regulated character ensures the most rapid aim achievement. This article has discussed the industrial structure of the agriculture in Russia. With the use of the system of indexes, the article has determined the directions, intensity, and speed of structural shifts. The influence of structural changes on agricultural production development has been found out. It is noticed that the changes in the industrial structure are synchronized with the changes in the organisation and economic structure. Efficiency assessment of structural changes allowed to trace the efficiency of structural changes and elaborate the main directions for agricultural policy improvement.

Keywords: Russian agricultural sectors, sectoral structure, organizational and economic structure, structural changes

Procedia PDF Downloads 161

Authors: Suthida Panwong, Jeeraporn Pekkoh, Yingmanee Tragoolpua, Aussara Panya

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Dengue virus (DENV) infection is a major public health problem in many countries, especially in tropical and subtropical countries. DENV infection causes dengue fever that can progress to serious conditions of dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), relevant to a high risk of mortality. However, there are no effective treatments available against the manifestation and fatalities. Currently, natural extracts have been widely used for the treatment of infectious diseases due to their safety, non-accumulation in the body, or lower side effects. Chlorella spp. is a microalgae with anti-viral activity, but there is not much report to support its ability to inhibit DENV infection. Thus, this study aimed to investigate the inhibitory effect of ethanolic extract from Chlorella sp. AARL G049, which was explored in Thailand on inhibition of DENV-2 infection. The inhibitory effect on viral infection was assessed using a foci-forming assay (FFA), which revealed that a concentration of 125 µg/mL could inhibit viral infection in Vero cells by 75.45±8.06% when treated at the same time as DENV-2 infection. Moreover, the extract at an equal concentration effectively reduced viral protein synthesis by 90.51±5.48% when assessed in human cell lines using enzyme-linked immunosorbent assay (ELISA). Concordantly, the number of infected cells after treatment was reduced as measured by immunofluorescent assay (IFA). Therefore, the finding of this study supports the potential use of Chlorella sp. extract to suppress DENV infection.

Keywords: viral infection, flavivirus, treatment, natural extract

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Authors: E. A. Abdel-Hakim

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The corn stemborer Sesamia cretica (Lederer), has been viewed in many parts of the world as a major pest of cultivated maize, graminaceous crops and sugarcane. Its life cycle is comprised of two different phases, one is the growth and developmental phase (non-diapause) and the other is diapause phase which takes place at the last larval instar. Several problems associated with the use of conventional insecticides, have strongly demonstrated the need for applying alternative safe compounds. Prominent among the prototypes of such prospective chemicals are the juvenoids; i.e. the insect (JH) mimics. In fact, the hormonal effect on metabolism has long been viewed as a secondary consequence of its direct action on specific energy-requiring biosynthetic mechanisms. Therefore, the present study was undertaken essentially in a rather systematic fashion as a contribution towards clarifying metabolic and energetic changes taking place during non-diapause wandering larvae as regulated by (JH) mimic. For this purpose, we applied two different doses of JH mimic (Ro 11-0111) in a single (standard) dose of 100µg or in a single dose of 20 µg/g bw in1µl acetone topically at the onset of nondiapause wandering larvae (WL). Energetic data were obtained by indirect calorimetry methods by conversion of respiratory gas exchange volumetric data, as measured manometrically using a Warburg constant respirometer, to caloric units (g-cal/g fw/h). The findings obtained can be given in brief; these treated larvae underwent supernumerary larval moults. However, this potential the wandering larvae proved to possess whereby restoration of larval programming for S. cretica to overcome stresses even at this critical developmental period. The results obtained, particularly with the high dose used, show that 98% wandering larvae were rescued to survive up to one month (vs. 5 days for normal controls), finally the formation of larval-adult intermediates. Also, the solvent controls had resulted in about 22% additional, but stationary moultings. The basal respiratory metabolism (O2 uptake and CO2 output) of the (WL), whether un-treated or larvae not had followed reciprocal U-shaped curves all along of their developmental duration. The lowest points stood nearly to the day of prepupal formation (571±187 µl O2/gfw/h and 553±181 µl CO2/gfw/h) during un-treated in contrast to the larvae treated with JH (210±48 µl O2/gfw/h and 335±81 µl CO2/gfw/h). Un-treated (normal) larvae proved to utilize carbohydrates as the principal source for energy supply; being fully oxidised without sparing any appreciable amount for endergonic conversion to fats. While, the juvenoid-treated larvae and compared with the acetone-treated control equivalents, there existed no distinguishable differences between them; both had been observed utilising carbohydrates as the sole source of energy demand and converting endergonically almost similar percentages to fats. The overall profile, treated and un-treated (WL) utilized carbohydrates as the principal source for energy demand during this stage.

Keywords: juvenile hormone, respiratory metabolism, Sesamia cretica, wandering phase

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Authors: Mohammad Mirjalili, Maryam Mohammdi, Loghman Karimi

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In this study, synthesis of zinc oxide nanoparticles was carried out along with the hydrolysis of Polyethylene terephthalate using sodium hydroxide to increase the surface activity and enhance the nanoparticles adsorption. The polyester fabrics were treated with zinc acetate and sodium hydroxide at ultrasound bath, resulting in the formation of ZnO nanospheres. The presence of zinc oxide on the surface of the polyethylene terephthalate was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The self-cleaning property of treated polyethylene terephthalate was evaluated through discoloring methylene blue stain under sunlight irradiation. The antibacterial activities of the samples against two common pathogenic bacteria including Escherichia coli and Staphylococcus aureus were also assessed. The results indicated that the photocatalytic and antibacterial activities of the ultrasound treated polyethylene terephthalate improved significantly.

Keywords: zinc oxide, polyethylene terephthalate, self-cleaning, antibacterial

Procedia PDF Downloads 317

Authors: A. V. Trukhanov, S. V. Trukhanov, L. V. Panina, V. G. Kostishin, V. A. Turchenko

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It has been shown that BaFe₁₂O₁₉ is a perspective room-temperature multiferroic material. A large spontaneous polarization was observed for the BaFe₁₂O₁₉ ceramics revealing a clear ferroelectric hysteresis loop. The maximum polarization was estimated to be approximately 11.8 μC/cm². The FeO₆ octahedron in its perovskite-like hexagonal unit cell and the shift of Fe³⁺ off the center of octahedron are suggested to be the origin of the polarization in BaFe₁₂O₁₉. The magnetic field induced electric polarization has been also observed in the doped BaFe_12-x-δSc_xM_δO₁₉ (δ=0.05) at 10 K and in the BaSc_xFe_12−xO₁₉ and SrSc_xFe_12−xO₁₉ (x = 1.3–1.7) M-type hexaferrites. The investigated BaFe_12-xD_xO₁₉ (x=0.1, D-Al³⁺, In³⁺) samples have been obtained by two-step “topotactic” reactions. The powder neutron investigations of the samples were performed by neutron time of flight method at High Resolution Fourier Diffractometer.

Keywords: substituted hexaferrites, ferrimagnetics, ferroelectrics, neutron powder diffraction, crystal and magnetic structures

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Authors: Sathish K. Gurupatham, Farhad Sayedzada, Naji Dauk, Valmiki Sooklal, Laura Ruhala

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It was shown recently that small particles and powders spontaneously disperse on liquid surfaces when they come into contact with the interface for the first time. This happens due to the combined effect of the capillary force, buoyant weight of the particle and the viscous drag that the particle experiences in the liquid. The particle undergoes oscillations normal to the interface before it comes to rest on the interface. These oscillations, in turn, induce a flow on the interface which disperses the particles radially outward. This phenomenon has a significant role in the pollination of sea plants such as Ruppia in which the formation of ‘pollen rafts’ is the first step. This paper investigates, experimentally, the influence of the temperature of the liquid on which this dispersion occurs. It was observed that the frequency of oscillations of the particles decreased with the increase in the temperature of the liquid. It is because the magnitude of capillary force also decreased when the temperature of the liquid increased.

Keywords: particle dispersion, capillary force, viscous drag, oscillations

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Authors: Karim Hrratha, Khaled Essalahb, Christophe Morellc, Henry Chermettec, Salima Boughdiria

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Among the carbon-carbon bond formation types, allylation of active methylene compounds with cyclic Baylis-Hillman (BH) alcohols is a reliable and widely used method. This reaction is a very attractive tool in organic synthesis of biological and biodiesel compounds. Thus, in view of an insistent and peremptory request for an efficient and straightly method for synthesizing the desired product, a thorough analysis of various aspects of the reaction processes is an important task. The product afforded by the reaction of active methylene with BH alcohols depends largely on the experimental conditions, notably on the catalyst properties. All experiments reported that catalysis is needed for this reaction type because of the poor ability of alcohol hydroxyl group to be as a suitable leaving group. Within the catalysts, several transition- metal based have been used such as palladium in the presence of acid or base and have been considered as reliable methods. Furthemore, acid catalysts such as BF3.OEt2, BiX3 (X= Cl, Br, I, (OTf)3), InCl3, Yb(OTf)3, FeCl3, p-TsOH and H-montmorillonite have been employed to activate the C-C bond formation through the alkylation of active methylene compounds. Interestingly a report of a smoothly process for the ability of 4-imethyaminopyridine(DMAP) to catalyze the allylation reaction of active methylene compounds with cyclic Baylis-Hillman (BH) alcohol appeared recently. However, the reaction mechanism remains ambiguous, since the C- allylation process leads to an unexpected product (noted P1), corresponding to a direct allylation instead of conjugate allylation, which involves the most electrophilic center according to the electron withdrawing group CO effect. The main objective of the present theoretical study is to better understand the role of the DMAP catalytic activity as well as the process leading to the end- product (P1) for the catalytic reaction of a cyclic BH alcohol with active methylene compounds. For that purpose, we have carried out computations of a set of active methylene compounds varying by R1 and R2 toward the same alcohol, and we have attempted to rationalize the mechanisms thanks to the acid–base approach, and conceptual DFT tools such as chemical potential, hardness, Fukui functions, electrophilicity index and dual descriptor, as these approaches have shown a good prediction of reactions products.The present work is then organized as follows: In a first part some computational details will be given, introducing the reactivity indexes used in the present work, then Section 3 is dedicated to the discussion of the prediction of the selectivity and regioselectivity. The paper ends with some concluding remarks. In this work, we have shown, through DFT method at the B3LYP/6-311++G(d,p) level of theory that: The allylation of active methylene compounds with cyclic BH alcohol is governed by orbital control character. Hence the end- product denoted P1 is generated by direct allylation.

Keywords: DFT calculation, gas phase pKa, theoretical mechanism, orbital control, charge control, Fukui function, transition state

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Authors: Patrik Scajev, Pavels Onufrijevs, Algirdas Mekys, Tadas Malinauskas, Dominykas Augulis, Liudvikas Subacius, Kuo-Chih Lee, Jevgenijs Kaupuzs, Arturs Medvids, Hung Hsiang Cheng

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In this study, we focused on the optoelectronic properties of the photodiodes prepared by using 200 nm thick Ge₀.₉₅Sn₀.₀₅ epitaxial layers on Ge/n-Si substrate with aluminum contacts. Photodiodes were formed on non-irradiated and Nd: YAG laser irradiated Ge₀.₉₅Sn₀.₀₅ layers. The samples were irradiated by pulsed Nd: YAG laser with 136.7-462.6 MW/cm² intensity. The photodiodes were characterized by using short laser pulses with the wavelength in the 2.0-2.6 μm range. The laser-irradiated diode was found more sensitive in the long-wavelength range due to laser-induced Sn atoms redistribution providing formation of graded bandgap structure. Sub-millisecond photocurrent relaxation in the diodes revealed their suitability for image sensors. Our findings open the perspective for improving the photo-sensitivity of GeSn alloys in the mid-infrared by pulsed laser processing.

Keywords: GeSn, laser processing, photodetector, infrared

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Authors: Kieren Luellman, Makenzi Rockwell, Eduardo Callegari, Nichole Haag, Chun Wu

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Multiple sclerosis (MS) is an autoimmune disorder that damages the myelin sheath of neurons in the central nervous system. The presence of Acinetobacter bacteria and anti-Acinetobacter antibodies in MS patients has led to the hypothesis that the bacteria may contribute to MS pathogenesis. In this study, the protein sequences of Acinetobacter baumannii were compared to five peptides from three mammalian myelin proteins, i.e., Proteolipid Protein (PLP): PLP 139-151, PLP 178-191, Myelin Basic Protein (MBP): MBP 84-104 and Myelin Oligodendrocyte Glycoprotein (MOG): MOG 35-55 and MOG 92-106 respectively, known to induce experimental autoimmune encephalomyelitis (EAE), a condition similar to MS. We found 11 hits (i.e., with five or more amino acid sequence similarity) in Acinetobacter baumannii, which are identical or similar to PLP139-151, 32 hits to PLP178-191, 35 to MBP 84-104, 41 hits to MOG 35-55 and 26 hits to MOG92-106. In addition, Western blotting was used to assess possible interaction between the bacterial proteins and human anti-MBP, anti-MOG, and anti-PLP antibodies produced in rabbits, corresponding to MBP 84-104, MOG 35-55, and PLP 139-151, respectively. We found that both human Polyclonal anti-MOG antibody and anti-PLP antibody recognized a protein or more proteins of the same molecular mass of around 25 kDa. in Acinetobacter baumannii. The results suggested that this/these protein(s) might potentially serve as antigen(s) to induce anti-MOG antibody and anti-PLP antibody production in mammalian B cells. The proteomic study identified 433 hits, among which the sequence of Acinetobacter baumannii protein 491 subunit A matches a previously published enzyme Acinetobacter 3-Oxoadipate CoA-Transferase, in which a fragment of its peptide was observed to recognize MS patient serum via ELISA method. Our findings might pave the road to understanding one of the pathogenesis mechanisms of MS.

Keywords: multiple sclerosis, pathogenesis, Acinetobacter baumannii, antibody recognition

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Authors: Silvia Moreno, Banu Iyisan, Hannes Gumz, Brigitte Voit, Dietmar Appelhans

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Polymersomes are materials which are considered as artificial counterparts of natural vesicles. The nanotechnology of such smart nanovesicles is very useful to enhance the efficiency of many therapeutic and diagnostic drugs. Those compounds show a higher stability, flexibility, and mechanical strength to the membrane compared to natural liposomes. In addition, they can be designed in detail, the permeability of the membrane can be controlled by different stimuli, and the surface can be functionalized with different biological molecules to facilitate monitoring and target. For this purpose, this study demonstrates the formation of multifunctional and pH sensitive polymersomes and their functionalization with different reactive groups or biomolecules inside and outside of polymersomes´ membrane providing by crossing the membrane and docking/undocking processes for biomedical applications. Overall, they are highly versatile and thus present new opportunities for the design of targeted and selective recognition systems, for example, in mimicking cell functions and in synthetic biology.

Keywords: multifunctionalized, pH stimulus, controllable release, cellular uptake

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Authors: Elizaveta Startseva, Elena Notina, Irina Bykova, Valentina Ulyumdzhieva, Natallia Zhabo

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With the various existing models of intercultural communication that contain a vast number of stages for foreign language acquisition, there is a need for conscious perception of the foreign culture. Such a process is associated with the emergence of linguistic conflict with the consistent students’ desire to solve the problem of the language differences, along with cultural discrepancies. The aim of this study is to present the modern ways and methods of removing psycholinguistic conflict through skills development in professional translation and intercultural communication. The study was conducted in groups of 1-4-year students of Medical Institute and Agro-Technological Institute RUDN university. In the course of training, students got knowledge in such disciplines as basic grammar and vocabulary of the English language, phonetics, lexicology, introduction to linguistics, theory of translation, annotating and referencing media texts and texts in specialty. The students learned to present their research work, participated in the University and exit conferences with their reports and presentations. Common strategies of removing linguistic and cultural conflict can be attributed to the development of such abilities of a language personality as a commitment to communication and cooperation, the formation of cultural awareness and empathy of other cultures of the individual, realistic self-esteem, emotional stability, tolerance, etc. The process of mastering a foreign language and culture of the target language leads to a reduplication of linguistic identity, which leads to successive formation of the so-called 'secondary linguistic personality.' In our study, we tried to approach the problem comprehensively, focusing on the translation gaps for technical and non-technical language still missing such a typology which could classify all of the lacunas on the same principle. When obtaining the background knowledge, students learn to overcome the difficulties posed by the national-specific and linguistic differences of cultures in contact, i.e., to eliminate the gaps (to fill in and compensate). Compensation gaps is a means of fixing it, the initial phase of elimination, followed in some cases and some not is filling semantic voids (plenus). The concept of plenus occurs in most cases of translation gaps, for example in the transcription and transliteration of (intercultural and exoticism), the replication (reproduction of the morphemic structure of words or idioms. In all the above cases the task of the translator is to ensure an identical response of the receptors of the original and translated texts, since any statement is created with the goal of obtaining communicative effect, and hence pragmatic potential is the most important part of its contents. The practical value of our work lies in improving the methodology of teaching English for specific purposes on the basis of psycholinguistic concept of the secondary language personality.

Keywords: lacuna, language barrier, plenus, secondary language personality

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Authors: Ali Reza Vaezi, Ouldouz Bakhshi Rad

Abstract:

Gully erosion is a widespread and often dramatic form of soil erosion caused by water during and immediately after heavy rainfall. It occurs when flowing surface water is channelled across unprotected land and washes away the soil along the drainage lines. The formation of gully is influenced by various factors, including climate, drainage surface area, slope gradient, vegetation cover, land use, and soil properties. It is a very important problem in semi-arid regions, where soils have lower organic matter and are weakly aggregated. Intensive agriculture and tillage along the slope can accelerate soil erosion by water in the region. There is little information on the development of gully erosion in agricultural rainfed areas. Therefore, this study was carried out to investigate the relationship between gully erosion and morphometric characteristics of the drainage area and the effects of soil properties and soil management factors (land use and tillage method) on gully development. A field study was done in a 900 km2 agricultural area in Hshtroud township located in the south of East Azarbijan province, NW Iran. Toward this, two hundred twenty-two gullies created in rainfed lands were found in the area. Some properties of gullies, consisting of length, width, depth, height difference, cross section area, and volume, were determined. Drainage areas for each or some gullies were determined, and their boundaries were drawn. Additionally, the surface area of each drainage, land use, tillage direction, and soil properties that may affect gully formation were determined. The soil erodibility factor (K) defined in the Universal Soil Loss Equation (USLE) was estimated based on five soil properties (silt and very fine sand, coarse sand, organic matter, soil structure code, and soil permeability). Gully development in each drainage area was quantified using its volume and soil loss. The dependency of gully development on drainage area characteristics (surface area, land use, tillage direction, and soil properties) was determined using correlation matrix analysis. Based on the results, gully length was the most important morphometric characteristic indicating the development of gully erosion in the lands. Gully development in the area was related to slope gradient (r= -0.26), surface area (r= 0.71), the area of rainfed lands (r= 0.23), and the area of rainfed tilled along the slope (r= 0.24). Nevertheless, its correlation with the area of pasture and soil erodibility factor (K) was not significant. Among the characteristics of drainage area, surface area is the major factor controlling gully volume in the agricultural land. No significant correlation was found between gully erosion and soil erodibility factor (K) estimated by the Universal Soil Loss Equation (USLE). It seems the estimated soil erodibility can’t describe the susceptibility of the study soils to the gully erosion process. In these soils, aggregate stability and soil permeability are the two soil physical properties that affect the actual soil erodibility and in consequence, these soil properties can control gully erosion in the rainfed lands.

Keywords: agricultural area, gully properties, soil structure, USLE

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