Search results for: hybrid iron nanoparticles

Authors: Oluwatosin A. Ijabadeniyi, Faith Semwayo

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Preference for consumption of fresh and minimally processed fruits and vegetables continues to be on the upward trend however food-borne outbreaks related to them have also been on the increase. In this study the effect of zinc oxide nanoparticles on controlling Listeria monocytogenes ATCC 7644 in tomatoes and carrots during storage was investigated. Nutrient broth was inoculated with Listeria monocytogenes ATCC 7644 and thereafter inoculated with 0.3mg/ml nano-zinc oxide solution and 1.2mg/ml nano-zinc oxide solution and 200ppm chlorine was used as a control. Whole tomatoes and carrots were also inoculated with Listeria monocytogenes ATCC 7644 after which they were dipped into zinc oxide nanoparticle solutions and chlorine solutions. 1.2 mg/ml had a 2.40 log reduction; 0.3mg/ml nano-zinc oxide solution had a log reduction of 2.15 in the broth solution. There was however a 4.89 log and 4.46 reduction by 200 ppm chlorine in tomato and carrot respectively. Control with 0.3 mg/ml zinc oxide nanoparticles resulted in a log reduction of 5.19 in tomato and 3.66 in carrots. 1.2 mg/ml nanozinc oxide solution resulted in a 5.53 log reduction in tomato and a 4.44 log reduction in carrots. A combination of 50ppm Chlorine and 0.3 mg/ml nanozinc oxide was also used and resulted in log reductions of 5.76 and 4.84 respectively in tomatoes and carrots. Treatments were more effective in tomatoes than in carrots and the combination of 50ppm Chlorine and 0.3 mg/ml ZnO resulted in the highest log reductions in both vegetables. Statistical analysis however showed that there was no significant difference between treatments with Chlorine and nanoparticle solutions. This study therefore indicates that zinc oxide nanoparticles have the potential for use as a control agent in the fresh produce industry.

Keywords: Listeria monocytogenes, nanoparticles, tomato, carrot

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Authors: Wasiu Olaniyi, Ofelia Omitogun

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Hybridization has been of importance in both research and commercial aquaculture due to its benefits such as increased growth rate, sex ratio manipulation, production of sterile species and many other desirable economic traits. In this study, we successfully produced hybrids between crosses of Clariid catfish species of Clarias gariepinus and Heterobranchus bidorsalis for stock improvement. Milt and eggs from parent broodstock of C. gariepinus and H. bidorsalis were collected for both intrageneric and interspecific hybridization, viz: same parent species crosses (♀C. gariepinus ×♂C. gariepinus; ♀H. bidorsalis × ♂H. bidorsalis) and inter-specific crosses (♀H. bidorsalis × ♂C. gariepinus; ♀C. gariepinus × ♂H. bidorsalis). These crosses were made in triplicates whereby the data on latency period, fertility, hatchability, deformity, and survival were recorded. A phenotypic form of distinction was registered in the hybrid ♀C. gariepinus × ♂H. bidorsalis that was smooth-greyed while its reciprocal cross was marpatic. The parent species C. gariepinus had greyed-marpatic color while the H. bidorsalis was yellowish-brown. Fertility data revealed the significant difference (p < 0.05) between the hybrid cross ♀C. gariepinus × ♂H. bidorsalis (88.00 ± 1.00%) compared to its reciprocal ♀H. bidorsalis × ♂C. gariepinus (71.67 ± 10.41%) which further had carried over effects to hatchability. The reciprocal ♀H. bidorsalis × ♂C. gariepinus recorded the highest deformity (11.67 ± 3.06%) that was significantly different (p < 0.05) from the rest of the crosses. Also, an outcome of equal sex ratio in the hybrids compared with the two parent species was shown. Specific growth rate (SGR) data revealed highest significant difference (p < 0.05) in the hybrid ♀C. gariepinus × ♂H. bidorsalis (2.64 ± 0.09%), followed by the cross of ♀C. gariepinus × ♂ C. gariepinus (1.91 ± 0.02%) while there were no significant differences (p > 0.05) between the reciprocal hybrid ♀H. bidorsalis × ♂C. gariepinus (2.20 ± 0.57%) and ♀H. bidorsalis × ♂H. bidorsalis (2.19 ± 0.19%). The SGR analysis proved that the crosses ♀C. gariepinus × ♂C. gariepinus had slow growth performance compared to its hybrid ♀C. gariepinus × ♂H. bidorsalis. Critical evaluation based on survival and specific growth performance showed the superiority of the hybrid ♀C. gariepinus × ♂H. bidorsalis. The least survival in reciprocal hybrid ♀H. bidorsalis × ♂C. gariepinus (27.33%) can be explained by significant deformity (11.67%) recorded due to maternal effects. Hence, the survival of hybrid ♀C. gariepinus × ♂H. bidorsalis was better.

Keywords: aquaculture, hybridization, Clarias gariepinus, Heterobranchus bidorsalis

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Authors: Lebogang L. R. Mphahlele, Bruce B. Sithole

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Chicken meat is the highest consumed meat in south Africa, with a per capita consumption of >33 kg yearly. Hence, South Africa produces over 250 million kg of waste chicken feathers each year, the majority of which is landfilled or incinerated. The discarded feathers have caused environmental pollution and natural protein resource waste. Therefore, the valorisation of waste chicken feathers is measured as a more environmentally friendly and cost-effective treatment. Feather contains 91% protein, the main component being beta-keratin, a fibrous and insoluble structural protein extensively cross linked by disulfide bonds. Keratin is usually converted it into nanofibers via electrospinning for a variety of applications. keratin nanofiber composites have many potential biomedical applications for their attractive features, such as high surface-to-volume ratio and very high porosity. The application of nanofibers in the biomedical wound dressing requires antimicrobial properties for materials. One approach is incorporating inorganic nanoparticles, among which silver nanoparticles played an important alternative antibacterial agent and have been studied against many types of microbes. The objective of this study is to combine synthetic polymer, chicken feather keratin, and antibacterial nanoparticles to develop novel electrospun antibacterial nanofibrous composites for possible wound dressing application. Furthermore, this study will converting a two-dimensional electrospun nanofiber membrane to three-dimensional fiber networks that resemble the structure of the extracellular matrix (ECM)

Keywords: chicken feather keratin, nanofibers, nanoparticles, nanocomposites, wound dressing

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Authors: Dipti Patra, Guguloth Uma, Smita Pradhan

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Registration is a fundamental task in image processing. It is used to transform different sets of data into one coordinate system, where data are acquired from different times, different viewing angles, and/or different sensors. The registration geometrically aligns two images (the reference and target images). Registration techniques are used in satellite images and it is important in order to be able to compare or integrate the data obtained from these different measurements. In this work, mutual information is considered as a similarity metric for registration of satellite images. The transformation is assumed to be a rigid transformation. An attempt has been made here to optimize the transformation function. The proposed image registration technique hybrid PSO-GA incorporates the notion of Particle Swarm Optimization and Genetic Algorithm and is used for finding the best optimum values of transformation parameters. The performance comparision obtained with the experiments on satellite images found that the proposed hybrid PSO-GA algorithm outperforms the other algorithms in terms of mutual information and registration accuracy.

Keywords: image registration, genetic algorithm, particle swarm optimization, hybrid PSO-GA algorithm and mutual information

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Authors: Doaa M. Atia, Faten H. Fahmy, Ninet M. A. El-Rahman, Hassan T. Dorra

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In this paper, the optimum design for renewable energy system powered an aquaculture pond was determined. Hybrid Optimization Model for Electric Renewable (HOMER) software program, which is developed by U.S National Renewable Energy Laboratory (NREL), is used for analyzing the feasibility of the stand-alone and hybrid system in this study. HOMER program determines whether renewable energy resources satisfy hourly electric demand or not. The program calculates energy balance for every 8760 hours in a year to simulate operation of the system. This optimization compares the demand for the electrical energy for each hour of the year with the energy supplied by the system for that hour and calculates the relevant energy flow for each component in the model. The essential principle is to minimize the total system cost while HOMER ensures control of the system. Moreover the feasibility analysis of the energy system is also studied. Wind speed, solar irradiance, interest rate and capacity shortage are the parameters which are taken into consideration. The simulation results indicate that the hybrid system is the best choice in this study, yielding lower net present cost. Thus, it provides higher system performance than PV or wind stand-alone systems.

Keywords: wind stand-alone system, photovoltaic stand-alone system, hybrid system, optimum system sizing, feasibility, cost analysis

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Authors: Monika Verma, Renuka Sharma, B. R. Gulati, Namita Singh

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In combination therapy, two chemotherapeutic agents work together in a collaborative action. It has appeared as one of the promising approaches to improve anti-cancer treatment efficacy. In the present investigation, piperine (P-NPS), paclitaxel (PTX NPS), and a combination of both, piperine-paclitaxel nanoparticle (Pip-PTX NPS), were made by the nanoprecipitation method and later characterized by PSA, DSC, SEM, TEM, and FTIR. All nanoparticles exhibited a monodispersed size distribution with a size of below 200 nm, zeta potential ranges from (-30-40mV) and a narrow polydispersity index (>0.3) of the drugs. The average encapsulation efficiency was found to be between 80 and 90%. In vitro release of drugs for nanoparticles was done spectrophotometrically. FTIR and DSC results confirmed the presence of the drug. The Pip-PTX NPS significantly inhibit cell proliferation as compared to the native drugs nanoparticles in the breast cancer cell line MCF-7. In addition, Pip-PTX NPS suppresses cells in colony formation and soft gel agar assay. Scratch migration and Transwell chamber invasion assays revealed that combined nanoparticles reduce the migration and invasion of breast cancer cells. Morphological studies showed that Pip-PTX NPS penetrates the cells and induces apoptosis, which was further confirmed by DNA fragmentation, SEM, and western blot analysis. Taken together, Pip-PTX NPS inhibits cell proliferation, anchorage dependent and anchorage independent cell growth, reduces migration and invasion, and induces apoptosis in cells. These findings support that combination therapy using Pip-PTX NPS represents a potential approach and could be helpful in the future for breast cancer therapy.

Keywords: piperine, paclitaxel, breast cancer, apoptosis

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Authors: M.F. Elkady, Sahar Zaki, Desouky Abd-El-Haleem

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Silver nanoparticles (AgNPs) are already widely prepared using different technologies. However, there are limited data on the effects of hydrogen ion concentration on nano-silver production. In this investigation, the impact of the pH reaction medium toward the particle size, agglomeration and the yield of the produced bio-synthesized silver were established. Quasi-spherical silver nanoparticles were synthesized through the biosynthesis green production process using the Egyptian E. coli bacterial strain 23N at different pH values. The formation of AgNPs has been confirmed with ultraviolet–visible spectra through identification of their characteristic peak at 410 nm. The quantitative production yield and the orientation planes of the produced nano-silver were examined using X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Quantitative analyses indicated that the silver production yield was promoted at elevated pH regarded to increase the reduction rate of silver precursor through both chemical and biological processes. As a result, number of the nucleus and thus the size of the silver nanoparticles were tunable through changing pH of the reaction system. Accordingly, the morphological structure and size of the produced silver and its aggregates were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. It was considered that the increment in pH value of the reaction media progress the aggregation of silver clusters. However, the presence of stain 23N biomass decreases the possibility of silver aggregation at the pH 7.

Keywords: silver nanoparticles, biosynthesis, reaction media pH, nano-silver characterization

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Authors: Madhu Gupta, G. P. Agrawa, Suresh P. Vyas

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Certain tumor cells overexpress a membrane-spanning molecule aminopeptidase N (CD13) isoform, which is the receptor for peptides containing the NGR motif. NGR-modified Docetaxel (DTX)-loaded PEG-b-PLGA polymeric nanoparticles (cNGR-DNB-NPs) were developed and evaluated for their in vitro potential in HT-1080 cell line. The cNGR-DNB-NPs containing particles were about 148 nm in diameter with spherical shape and high encapsulation efficiency. Cellular uptake was confirmed both qualitatively and quantitatively by Confocal Laser Scanning Microscopy (CLSM) and flow cytometry. Both quantitatively and qualitatively results confirmed the NGR conjugated nanoparticles revealed the higher uptake of nanoparticles by CD13-overexpressed tumor cells. Free NGR inhibited the cellular uptake of cNGR-DNB-NPs, revealing the mechanism of receptor mediated endocytosis. In vitro cytotoxicity studies demonstrated that cNGR-DNB-NPs, formulation was more cytotoxic than unconjugated one, which were consistent well with the observation of cellular uptake. Hence, the selective delivery of cNGR-DNB-NPs formulation in CD13-overexpressing tumors represents a potential approach for the design of nanocarrier-based dual targeted delivery systems for targeting the tumor cells and vasculature.

Keywords: solid Tumor, docetaxel, targeting, NGR ligand

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Authors: Eva Karaskova, Jana Volejnikova, Dusan Holub, Maria Velganova-Veghova, Michaela Spenerova, Dagmar Pospisilova

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Background: Hepcidin is the central regulator of iron metabolism. Its production is mainly affected by an iron deficiency and the presence of inflammatory activity in the body. The aim of this study was to compare serum hepcidin levels in paediatric patients with newly diagnosed inflammatory bowel disease and hepcidin levels during maintenance therapy, correlate changes of serum hepcidin levels with selected markers of iron metabolism and inflammation and type of provided treatment. Methods: Children with newly diagnosed Crohn's disease (CD) and ulcerative colitis (UC) were included in this prospective study. Blood and stool samples were collected before treatment (baseline). Serum hepcidin, hemoglobin levels, platelet counts, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), interleukin-6 (IL 6), ferritin, iron, soluble transferrin receptors, and fecal calprotectin were assessed. The same parameters were measured and compared with the baseline levels in the follow-up period, during maintenance therapy (average of 39 months after diagnosis). Results: Patients with CD (n=30) had higher serum hepcidin levels (expressed as a median and interquartile range) at diagnosis than subjects with UC (n=13). These levels significantly decreased during the follow-up (from 36.5 (11.5-79.6) ng/ml to 2.1 (0.9-6.7) ng/ml). Contrarily, no significant serum hepcidin level changes were observed in UC (from 5.4 (3.4-16.6) ng/ml to 4.8 (0.9-8.1) ng/ml). While in children with CD hepcidin level dynamics correlated with disease activity and inflammatory markers (ESR, CRP), an only correlation with serum iron levels was observed in patients with UC. Conclusion: Children with CD had higher serum hepcidin levels at diagnosis compared to subjects with UC. Decrease of serum hepcidin in the CD group during anti-inflammatory therapy has been observed, whereas low hepcidin levels in children with UC have remained unchanged. Acknowledgment: This study was supported by grant MH CZ–DRO (FNOl, 00098892).

Keywords: children, Crohn's disease, ulcerative colitis, anaemia, hepcidin

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Authors: Manjula Kola, K. Chandralekha

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Anaemia is one of the world’s most widespread health problems. Prevalence of anemia in south Asia is among the highest in the world. Iron deficiency anemia accounts for almost 85 percent of all types of anemia in India and affects more than half of the total population. Women of childbearing age particularly pregnant women, infants, preschool children and adolescents are at greatest risk of developing iron deficiency anemia. In India, 74 percent children between 6-35 months of age are anemic. Children between 1-6 years in major cities are found with a high prevalence rate of 64.8 percent. Iron deficiency anemia is not only a public health problem, but also a development problem. Its prevention and reduction must be viewed as investment in human capital that will enhance development and reduce poverty. Ending this hidden hunger in the form of iron deficiency is the most important achievable international health goal. Eliminating the underlying problem is essential to the sustained elimination of the iron deficiency anemia. The intervention programmes toward the sustained elimination need to be broadly based so that interventions become accepted community practices. Hence, intervention strategies need to go well beyond traditional health and nutrition systems and based upon empowering people and communities so that they will be capable of arranging for and sustaining an adequate intake of foods with respect to iron, independent of external support. Such strategies must necessarily be multisectoral and integrate interventions with social communications, evaluation and surveillance. The main objective of the study was to design a community based Nutrition intervention using theoretical framework of social marketing to sustain improvement of iron nutriture among preschool children. In order to carryout the study eight rural communities In Chittoor district of Andhra Pradesh, India were selected. A formative research was carryout for situational analysis and baseline data was generated with regard to demographic and socioeconomic status, dietary intakes, Knowledge, Attitude and Practices of the mothers of preschool children, clinical and hemoglobin status of the target group. Based on the formative research results, the research area was divides into four groups as experimental area I,II,III and control area. A community based, integrated and comprehensive social marketing intervention was designed based on various theories and models of nutrition education/ communication. In Experimental area I, Nutrition intervention using social marketing and a weekly iron folic acid supplementation was given to improve iron nutriture of preschool children. In experimental area II, Social marketing alone was implemented and in experimental area III Iron supplementation alone was given. No intervention was given in control area. The Impact evaluation revealed that among different interventions tested, the integrated social marketing intervention resulted best outcomes. The overall observations of the study state that social marketing, an integrated and functional strategy for nutrition communication to prevent and control iron deficiency. Various theoretical frame works / models for nutrition communication facilitate to design culturally appropriate interventions thus achieved improvements in the knowledge, attitude and practices there by resulting successful impact on nutritional status of the target groups.

Keywords: anemia, iron deficiency, social marketing, theoretical framework

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Authors: P.Kiruthika, K. Ramani

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This paper presented the design and advancement of a single-phase 27-level Hybrid Multilevel DC-AC Converter interfacing with Photo Voltaic. In this context, the Multicarrier Pulse Width Modulation method can be implemented in 27-level Hybrid Multilevel Inverter for generating a switching pulse. Perturb & Observer algorithm can be used in the Maximum Power Point Tracking method for the Photo Voltaic system. By implementing Maximum Power Point Tracking with three separate solar panels as an input source to the 27-level Hybrid Multilevel Inverter. This proposed method can be simulated by using MATLAB/simulink. The result shown that the proposed method can achieve silky output wave forms, more flexibility in voltage range, and to reduce Total Harmonic Distortion in medium-voltage drives.

Keywords: Multi Carrier Pulse Width Modulation Technique (MCPWM), Multi Level Inverter (MLI), Maximum Power Point Tracking (MPPT), Perturb and Observer (P&O)

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Authors: Jia-Shiun Chen, Hsiu-Ying Hwang

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Hybrid electric vehicles can reduce pollution and improve fuel economy. Power-split hybrid electric vehicles (HEVs) provide two power paths between the internal combustion engine (ICE) and energy storage system (ESS) through the gears of an electrically variable transmission (EVT). EVT allows ICE to operate independently from vehicle speed all the time. Therefore, the ICE can operate in the efficient region of its characteristic brake specific fuel consumption (BSFC) map. The two-mode powertrain can operate in input-split or compound-split EVT modes and in four different fixed gear configurations. Power-split architecture is advantageous because it combines conventional series and parallel power paths. This research focuses on input-split and compound-split modes in the two-mode power-split powertrain. Fuzzy Logic Control (FLC) for an internal combustion engine (ICE) and PI control for electric machines (EMs) are derived for the urban driving cycle simulation. These control algorithms reduce vehicle fuel consumption and improve ICE efficiency while maintaining the state of charge (SOC) of the energy storage system in an efficient range.

Keywords: hybrid electric vehicle, fuel economy, two-mode hybrid, fuzzy control

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Authors: Sang Beom Kim, Kyung Ju Kim, Myung Hoon Cho, Ji Hoon Kim, Soo Hyung Kim

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In this study, we systematically investigated the effect of nanoscale energetic materials in formulations of aluminum nanoparticles (Al NPs; heat source)/copper oxide nanoparticles (CuO NPs; oxidizer) on the combustion and gas-generating properties of sodium azide microparticles (NaN3 MPs; gas-generating agent) for potential applications in gas generators. The burn rate of the NaN3 MP/CuO NP composite powder was only ~0.3 m/s. However, the addition of Al NPs to the NaN3 MP/CuO NP matrix caused the rates to reach ~5.3 m/s, respectively. In addition, the N2 gas volume flow rate generated by the ignition of the NaN3 MP/CuO NP composite powder was only ~0.6 L/s, which was significantly increased to ~3.9 L/s by adding Al NPs to the NaN3 MP/CuO NP composite powder. This suggested that the highly reactive NPs, with the assistance of CuO NPs, were effective heat-generating sources enabling the complete thermal decomposition of NaN3 MPs upon ignition. Al NPs were highly effective in the gas generators because of the increased reactivity induced by the reduced particle size. Finally, we successfully demonstrated that a homemade airbag with a specific volume of ~140 mL could be rapidly and fully inflated by the thermal activation of nanoscale energetic material-added gas-generating agents (i.e., NaN3 MP/Al NP/CuO NP composites) within the standard time of ~50 ms for airbag inflation.

Keywords: nanoenergetic materials, aluminum nanoparticles, copper oxide nanoparticles, gas generators

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Authors: Maryam Sadeghi, Claude Bazin, Daniel Hodouin, Laura Perez Barnuevo

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The performance of a separation process is usually evaluated using performance indices calculated from elemental assays readily available from the chemical analysis laboratory. However, the separation process performance is essentially related to the properties of the minerals that carry the elements and not those of the elements. Since elements or metals can be carried by valuable and gangue minerals in the ore and that each mineral responds differently to a mineral processing method, the use of only elemental assays could lead to erroneous or uncertain conclusions on the process performance. This paper discusses the advantages of using performance indices calculated from minerals content, such as minerals recovery, for process performance assessments. A method is presented that uses elemental assays to estimate the minerals content of the solids in various process streams. The method combines the stoichiometric composition of the minerals and constraints of mass conservation for the minerals through the concentration process to estimate the minerals content from elemental assays. The advantage of assessing a concentration process using mineral based performance indices is illustrated for an iron ore concentration circuit.

Keywords: data reconciliation, iron ore concentration, mineral composition, process performance assessment

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Authors: Mina Mortazavi, Hamid Ronagh, Pezhman Sharafi

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The new concept of a cold formed-hot rolled hybrid steel wall panel system is introduced to overcome the deficiency in lateral load resisting capacity of cold-formed steel structures. The hybrid system is composed of a cold-formed steel part laterally connected to hot rolled part. The hot rolled steel part is responsible for carrying the whole lateral load; while the cold formed steel part is only required to transfer the lateral load to the hot rolled part without any local failure. The vertical load is beared by both hot rolled, and cold formed steel part, proportionally. In order to investigate the lateral performance of the proposed system, it should be tested under simultaneous lateral and vertical load. The main concern is to deliver the loads to each part during the test to simulate the real load distribution in the structure. In this paper, a detailed description of the proposed wall panel system and the designed testing rig is provided.

Keywords: cold-formed steel, hybrid system, wall panel system, testing rig design

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Authors: Deli Mona, Rafika Husni

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The aim of this research is to evaluate the effect of lighting distance on surface hardness of light composite resin. We held laboratory experimental research with post-test only group design. The samples used are 30 disc-like hybrid composite resins with the diameter is 6 mm and the thickness is 2 mm, lighted by an LED for 20 seconds. They were divided into 3 groups, and every group was consisted by 10 samples, which were 0 mm, 2 mm, and 5 mm lighting distance group. Every samples group was treated with hardness test, Vicker Hardness Test, then analyzed with one-way ANOVA test to evaluate the effect of lighting distance differences on surface hardness of light composite resin. Statistic test result shown hardness mean change of composite renin between 0 mm and 2 mm lighting distance with 0.00 significance (p<0.05), between 0 mm and 5 mm lighting distance with 0.00 significance (p<0.05), and 2 mm and 5 mm lighting distance with 0.05 significance (p<0.05). According to the result of this research, we concluded that the further lighting distance, the more surface hardness decline of hybrid composite resin.

Keywords: composite resin hybrid, tip distance, microhardness, light curing LED

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Authors: Al-Sayed A. Bakr, W. A. Makled

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The precipitated low magnesium calcite ooids in assembled softening unit from natural Mediterranean seawater samples were used as adsorbent media in a comparative study with granular activated carbon media in a two separated single-media filtration vessels (operating in parallel) for removal of iron from aqueous solutions. In each vessel, the maximum bed capacity, which required to be filled, was 13.2 l and the bed filled in the vessels of ooids and GAC were 8.6, and 6.6 l, respectively. The operating conditions applied to the semi-pilot filtration unit were constant pH (7.5), different temperatures (293, 303 and 313 k), different flow rates (20, 30, 40, 50 and 60 l/min), different initial Fe(II) concentrations (15–105 mg/ l) and the calculated adsorbent masses were 34.1 and 123 g/l for GAC and calcite ooids, respectively. At higher temperature (313 k) and higher flow rate (60 l/min), the maximum adsorption capacities for ferrous ions by GAC and calcite ooids filters were 3.87 and 1.29 mg/g and at lower flow rate (20 l/min), the maximum adsorption capacities were 2.21 and 3.95 mg/g, respectively. From the experimental data, Freundlich and Langmuir adsorption isotherms were used to verify the adsorption performance. Therefore, the calcite ooids could act as new highly effective materials in iron removal from aqueous solutions.

Keywords: water treatment, calcite ooids, activated carbon, Fe(II) removal, filtration

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Authors: Hoda Aleali, Nastran Mansour, Maryam Mirzaie

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In this paper, we study the optical nonlinearities of Silver sulfide (Ag2S) nanostructures dispersed in the Dimethyl sulfoxide (DMSO) under exposure to 532 nm, 15 nanosecond (ns) pulsed laser irradiation. Ultraviolet–visible absorption spectrometry (UV-Vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM) are used to characterize the obtained nanocrystal samples. The band gap energy of colloid is determined by analyzing the UV–Vis absorption spectra of the Ag2S NPs using the band theory of semiconductors. Z-scan technique is used to characterize the optical nonlinear properties of the Ag2S nanoparticles (NPs). Large enhancement of two photon absorption effect is observed with increase in concentration of the Ag2S nanoparticles using open Z-scan measurements in the ns laser regime. The values of the nonlinear absorption coefficients are determined based on the local nonlinear responses including two photon absorption. The observed aperture dependence of the Ag2S NP limiting performance indicates that the nonlinear scattering plays an important role in the limiting action of the sample.The concentration dependence of the optical liming is also investigated. Our results demonstrate that the optical limiting threshold decreases with increasing the silver sulfide NPs in DMSO.

Keywords: nanoscale materials, silver sulfide nanoparticles, nonlinear absorption, nonlinear scattering, optical limiting

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Authors: Akbar Esmaeili, Fateme Dadashi

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Bismuth can increase radiation and reduce the dose of radiotherapy. On the other hand, hyaluronic acid plays a role in healing damaged cells, and melittin has been used to destroy cancer cells. This research aims to destroy eye cancer cells and accelerate the recovery of damaged healthy cells during treatment. In this research, we used this nanoparticle, the sol-gel method. According to the optimization process that was carried out, we obtained the optimal value of the desired variables for the manufacture of nanoparticles. The advantage of doing this is reducing the amount of medicine used, as a result of reducing the number of side effects during the treatment and using melittin as an anti-eye cancer drug and the presence of hyaluronic acid to accelerate the recovery of cells, as well as coating the bismuth nanoparticle with chitosan to increase the half-life of the nanoparticle and prevent its adhesion.

Keywords: synthesis, nanoparticles, coated, cancer

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Authors: Alaa Koaik, Bruno Jurkiewiez, Sylvain Bel

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Recently, the use of GFRP pultruded profiles increased in the domain of civil engineering especially in the construction of sandwiched slabs and footbridges. However, under heavy loads, the risk of using these profiles increases due to their high deformability and instability as a result of their weak stiffness and orthotropic nature. A practical solution proposes the assembly of these profiles with concrete slabs to create a stiffer hybrid element to support higher loads. The connection of these two elements is established either by traditional means of steel studs (bolting in our case) or bonding technique. These two techniques have their advantages and disadvantages regarding the mechanical behavior and in-situ implementation. This paper presents experimental results of interface characterization and bending behavior of two hybrid beams, PB7 and PB8, designed and constructed using both connection techniques. The results obtained are exploited to design and build a hybrid footbridge BPBP1 which is tested within service limits (elastic domain). Analytical methods are also developed to analyze the behavior of these structures in the elastic range and the ultimate phase. Comparisons show acceptable differences mainly due to the sensitivity of the GFRP moduli as well as the non-linearity of concrete elements.

Keywords: analytical model, concrete, flexural behavior, GFRP pultruded profile, hybrid structure, interconnection slip, push-out

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Authors: Sarah Iaquinta, Christophe Blanquart, Elena Ishow, Sylvain Freour, Frederic Jacquemin, Shahram Khazaie

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Nanoparticles have recently emerged as a possible cancer treatment tool. Several formulations have been used to enhance the uptake of these nanoparticles by cancer cells and avoid their immediate clearance when administrated in vivo. Most of the previous studies focus on the investigation of the influence of the mechanical properties of the cell membrane and the particle. However, these studies do not account for the variation of adhesion and tension during the wrapping of the nanoparticle by the membrane. These couplings should be considered since the cell adapts to the interaction with the nanoparticle by, e.g., increasing the number of interactions (consequently leading to an increase of the cell membrane/nanoparticle adhesion) and by reorganizing its cytoskeleton, leading to the releasing of the tension of the cell membrane. The main contribution of this work is the proposal of a novel model for representing the cellular uptake of rigid circular nanoparticles based on an energetic model tailored to take into account the adaptation of the nanoparticle/cell membrane adhesion and of the membrane stress during wrapping. Several coupling models using sigmoidal functions are considered and compared. The study calculations revealed that the results considering constant parameters underestimated the final wrapping degree of the particle by up to 50%.

Keywords: adhesion, cellular adaptation, cellular uptake, mechanical properties, tension

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Authors: Houria Rezala, Jose Luis Valverde, Amaya Romero, Alessandra Molinari, Andrea Maldotti

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A pillared montmorillonite containing iron doped titania (Fe/Ti-PILC) has been prepared from a natural clay. This material has been characterized by X-ray diffraction, nitrogen adsorption, temperature programmed desorption of ammonia, inductively coupled plasma atomic emission spectroscopy, atomic absorption, and diffuse reflectance UV-VIS spectroscopy. The layer structure of Fe/Ti-PILC resulted to be ordered with an insertion of pillars, which caused a slight increase in the basal spacing of the clay. Its specific surface area was about three times larger than that of the parent Na-montmorillonite due principally to the creation of a remarkable microporous network. The doped material was a robust photocatalyst able to oxidize liquid alkyl aromatics to the corresponding carbonylic derivatives, using O2 as the oxidizing species, at mild pressure and temperature conditions. Accumulation of valuable carbonylic derivatives was possible since their over-oxidation to carbon dioxide was negligible. Fe/Ti-PILC was able to discriminate between toluene and cyclohexane in favor of the aromatic compound with an efficiency that is about three times higher than that of titanium pillared clays (Ti-PILC). It is likely that the addition of iron favored the formation of new acid sites able to interact with the aromatic substrate. Iron doping caused a significant TiO2 visible light-induced activity (wavelength > 400 nm) with only minor negative effects on its performance under UV-light irradiation (wavelength > 290 nm).

Keywords: alkyl aromatics oxidation, heterogeneous photocatalysis, iron doping, pillared clays

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Authors: Mojtaba Ghodsi, Hamidreza Ziaifar, Morteza Mohammadzaheri, Payam Soltani

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In this paper, the performance of a medium power (25 kW/25 kHz) hybrid inverter with a reactive transformer is investigated. To analyze the sensitivity of the inverster, the RSM technique is employed to manifest the effective factors in the inverter to minimize current passing through the Insulated Bipolar Gate Transistors (IGBTs) (current stress). It is revealed that the ratio of the axillary inductor to the effective inductance of resonant inverter (N), is the most effective parameter to minimize the current stress in this type of inverter. In practice, proper selection of N mitigates the current stress over IGBTs by five times. This reduction is very helpful to keep the IGBTs at normal temperatures.

Keywords: analytical analysis, hybrid resonant inverter, reactive transformer, response surface method

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Authors: Juan Patricio Ibáñez, Exequiel López

Abstract:

A method for synthesizing copper nanoparticles through an electrochemical approach is proposed, employing surfactants to stabilize the size of the newly formed nanoparticles. The electrolyte was made up of a matrix of H₂SO₄ (190 g/L) having Cu²⁺ (from 3.2 to 9.5 g/L), sodium dodecyl sulfate -SDS- (from 0.5 to 1.0 g/L) and Tween 80 (from 0 to 7.5 mL/L). Tween 80 was used in a molar relation of 1 to 1 with SDS. A glass cell was used, which was in a thermostatic water bath to keep the system temperature, and the electrodes were cathodic copper as an anode and stainless steel 316-L as a cathode. This process was influenced by the control exerted through the initial copper concentration in the electrolyte and the applied current density. Copper nanoparticles of electrolytic purity, exhibiting a spherical morphology of varying sizes with low dispersion, were successfully produced, contingent upon the chemical composition of the electrolyte and current density. The minimum size achieved was 3.0 nm ± 0.9 nm, with an average standard deviation of 2.2 nm throughout the entire process. The deposited copper mass ranged from 0.394 g to 1.848 g per hour (over an area of 25 cm²), accompanied by an average Faradaic efficiency of 30.8% and an average specific energy consumption of 4.4 kWh/kg. The chemical analysis of the product employed X-ray powder diffraction (XRD), while physical characteristics such as size and morphology were assessed using atomic force microscopy (AFM). It was identified that the initial concentration of copper and the current density are the variables defining the size and dispersion of the nanoparticles, as they serve as reactants in the cathodic half-reaction. The presence of surfactants stabilizes the nanoparticle size as their molecules adsorb onto the nanoparticle surface, forming a thick barrier that prevents mass transfer with the exterior and halts further growth.

Keywords: copper nanopowder, electrochemical synthesis, current density, surfactant stabilizer

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Authors: Emineh Tsegahun Gedif

Abstract:

Zinc oxide nanoparticles (ZnO NPs) have garnered significant attention due to their diverse applications encompassing catalytic, optical, photonic, and antibacterial properties. In this study, we successfully synthesized zinc oxide nanoparticles using a rapid, environmentally benign, and cost-effective method. Neem (Azadirachta indica) leaf extract served as the reducing agent for Zn (NO₃)₂.6H2O solution under optimized conditions (pH = 9). Qualitative screening techniques and FT-IR Spectroscopy confirmed the presence of active biomolecules such as flavonoids, phenolic groups, alkaloids, terpenoids, and tannins within the Neem leaf extract, both before and after reduction. The formation of ZnO NPs was visually evident through a distinct color change from colorless to light yellow. The biosynthesized nanoparticles underwent comprehensive characterization through UV-visible, FT-IR, and XRD spectroscopies. The reduction process proved to be straightforward and user-friendly, with UV-visible spectroscopy demonstrating a surface plasmon resonance (SPR) at 321 nm, unequivocally confirming the ZnO NP formation. X-ray diffraction analysis elucidated the crystal structure, revealing an average particle size of approximately 20 nm using Scherrer's equation based on the line width of the plane. Furthermore, the synthesized zinc oxide nanoparticles were evaluated for their antimicrobial properties against both Gram-positive and Gram-negative bacteria. The results showcased significant inhibitory activity, with the highest zone of inhibition observed against Escherichia coli (15 mm) and comparatively lower activity against Staphylococcus aureus. This research underscores the potential of Neem leaf extract-mediated synthesis of ZnO NPs as an eco-friendly and effective approach for various applications, including antibacterial agents.

Keywords: zinc oxide nanoparticles (ZnO NPs), bioreducing agent, green synthesis, antibacterial activity

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Authors: Pawel Albrycht, Monika Ksiezopolska-Gocalska, Robert Holyst

Abstract:

Surface Enhanced Raman Spectroscopy (SERS) is a technique of growing importance not only in purely scientific research related to analytical chemistry. It finds more and more applications in broadly understood testing - medical, forensic, pharmaceutical, food - and everywhere works perfectly, on one condition that SERS substrates used for testing give adequate enhancement, repeatability, and homogeneity of SERS signal. This is a problem that has existed since the invention of this technique. Some laboratories use as SERS amplifiers colloids with silver or gold nanoparticles, others form rough silver or gold surfaces, but results are generally either weak or unrepeatable. Furthermore, these structures are very often highly specific - they amplify the signal only of a small group of compounds. It means that they work with some kinds of analytes but only with those which were used at a developer’s laboratory. When it comes to research on different compounds, completely new SERS 'substrates' are required. That underlay our decision to develop universal substrates for the SERS spectroscopy. Generally, each compound has different affinity for both silver and gold, which have the best SERS properties, and that's what depends on what signal we get in the SERS spectrum. Our task was to create the platform that gives a characteristic 'fingerprint' of the largest number of compounds with very high repeatability - even at the expense of the intensity of the enhancement factor (EF) (possibility to repeat research results is of the uttermost importance). As specified above SERS substrates are offered by SERSitive company. Applied method is based on cyclic potentiodynamic electrodeposition of silver or silver-gold nanoparticles on the conductive surface of ITO-coated glass at controlled temperature of the reaction solution. Silver nanoparticles are supplied in the form of silver nitrate (AgNO₃, 10 mM), gold nanoparticles are derived from tetrachloroauric acid (10 mM) while sodium sulfite (Na₂O₃, 5 mM) is used as a reductor. To limit and standardize the size of the SERS surface on which nanoparticles are deposited, photolithography is used. We secure the desired ITO-coated glass surface, and then etch the unprotected ITO layer which prevents nanoparticles from settling at these sites. On the prepared surface, we carry out the process described above, obtaining SERS surface with nanoparticles of sizes 50-400 nm. The SERSitive platforms present highly sensitivity (EF = 10⁵-10⁶), homogeneity and repeatability (70-80%).

Keywords: electrodeposition, nanoparticles, Raman spectroscopy, SERS, SERSitive, SERS platforms, SERS substrates

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Authors: Ilma Robo, Saimir Heta, Edona Hasanaj, Vera Ostreni

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The hybrid layer, the way it is created and how it is protected against degradation over time, is the key to the clinical success of a composite restoration. The composite supports the dentinal structure exactly with the realized surface of microretension. Thus, this surface is in direct proportion to its size versus the duration of clinical use of composite dental restoration. Micro-retention occurs between dentin or acidified enamel and adhesive resin extensions versus pre-prepared spaces, such as hollow dentinal tubules. The way the adhesive resin binds to the acidified dentinal structure depends on the physical or chemical factors of this interrelationship between two structures with very different characteristics. During the acidification process, a precursor to the placement of the adhesive resin layer, activation of metaloproteinases of dental origin occurs, enzymes which are responsible for the degradation of the hybrid layer. These enzymes have expressed activity depending on the presence of Zn2 + or Ca2 + ions. There are several ways to inhibit these enzymes, and consequently, there are several ways to inhibit the degradation process of the hybrid layer. The study aims to evaluate chlorhexidine as a solution element, inhibitor of dentin activated metalloproteinases, as a result of the application of acidification. This study aims to look at this solution in advantage or contraindication theories, already published in the literature.

Keywords: hybrid layer, chlorhexidine, degradation, application

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Authors: Nyumbaiza Tambwe

Abstract:

The purpose of this paper is to demonstrate that hybrid urban agriculture as the most practiced type of urban agriculture in the majority of cities in sub-Saharan Africa can be taken as an alternative strategy in fighting food insecurity. The practice not only provides food, generates income and fights against unemployment; it constitutes a true back-up for households during crisis linked to the nature of capitalism system. African cities are mostly characterized by rapid population growth, rampant poverty, and high level of unemployment and food insecurity. Those factors and many others are at the origin of the emergence of urban agriculture in many African cities. Based particularly on results of research undertaken in the Democratic Republic of Congo (DRC), but also in comparison with those realized in other parts of the African continent, the paper is a case study. Therefore, the paper firstly describes the situation of food in Africa, secondly, presents hybrid urban agriculture as a household strategy in fighting food insecurity and finally shows possibilities and limits of this practice.

Keywords: alternative strategy, food security, household strategy, hybrid urban agriculture

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Authors: Chen-En Lin, Lih-Rou Rau, Jiunn-Woei Liaw, Shiao-Wen Tsai

Abstract:

The unique optical properties of plasmon resonance metallic particles have attracted considerable applications in the fields of physics, chemistry and biology. Metal-Enhanced Fluorescence (MEF) effect is one of the useful applications. MEF effect stated that fluorescence intensity can be quenched or be enhanced depending on the distance between fluorophores and the metal nanoparticles. Silver nanoparticles have used widely in antibacterial studies. However, the major limitation for silver nanoparticles (AgNPs) in biomedical application is well-known cytotoxicity on cells. There were numerous literatures have been devoted to overcome the disadvantage. The aim of the study is to evaluate the cytotoxicity and biocompatibility of silica coated AgNPs against NIH-3T3 cells. The results were shown that NIH-3T3 cells started to detach, shrink, become rounded and finally be irregular in shape after 24 h of exposure at 10 µg/ml AgNPs. Besides, compared with untreated cells, the cell viability significantly decreased to 60% and 40% which were exposed to 10 µg/ml and 20 µg/ml AgNPs respectively. The result was consistent with previously reported findings that AgNPs induced cytotoxicity was concentration dependent. However, the morphology and cell viability of cells appeared similar to the control group when exposed to 20 µg/ml of silica coated AgNPs. We further utilized the dark-field hyperspectral imaging system to analysis the optical properties of the intracellular nanoparticles. The image displayed that the red shift of the surface plasmonic resonances band of the enclosed AgNPs further confirms the agglomerate of the AgNPs rather than their distribution in cytoplasm. In conclusion, the study demonstrated the silica coated of AgNPs showed well biocompatibility and significant lower cytotoxicity compared with bare AgNPs.

Keywords: silver nanoparticles, silica, cell viability, morphology

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Authors: Seyedeh Narjes Hosseini, Mohammad Hossein Enayati, Fathallah Karimzadeh, Nigel Mark Sammes

Abstract:

The synthesis of CuFe2O4 spinel powders by an optimized combustion-like process followed by calcinations is described herein. The samples were characterized by X-ray diffraction (XRD), differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), dilatometry and 4-probe DC methods. Different glycine to nitrate (G/N) ratios of 1 (fuel-deficient), 1.48 (stoichiometric) and 2 (fuel-rich) were employed. Calcining the as-prepared powders at 800 and 1000°C for 5 hours showed that the 2 ratio results in the formation of desired copper spinel single phase at both calcinations temperatures. For G/N=1, formation of CuFe2O4 takes place in three steps. First, iron and copper nitrates decomposes to iron oxide and pure copper. Then, copper transforms to copper oxide and finally, copper and iron oxides react to each other to form copper ferrite spinel phase. The electrical conductivity and the coefficient of thermal expansion of the sintered pelletized samples were obtained 2 S.cm-1 (800°C) and 11×10-6 °C-1 (25-800°C), respectively.

Keywords: SOFC interconnect coatings, Copper ferrite, Spinels, electrical conductivity, Glycine–nitrate process

Procedia PDF Downloads 477