Search results for: shape properties

Authors: R. Gounina-Allouane, N. Ouali, F. Z. Berrabah, A. Bentaleb

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For a long time, the Gram-positive spore-forming bacteria Bacillus thuringiensis (Bt) has been widely used in biological control against devastating and disease vectors insects. This is due to the insecticidal activity of its crystalline parasporal inclusion (crystals) predominantly comprised of one or more proteins (Cry and Cyt proteins) also called δ-endotoxins, produced during sporulation. The shape and composition of Bt crystals vary among strains and crystalline proteins are extremely varied (more than 475 cry gene were discovered). The insecticidal activity of Bt crystals is very well studied, thus their insecticidal mode of action is well established, however, their antimicrobial effect is largely unknown. The lack of data on the antimicrobial effect of crystalline proteins of Bt and the need for searching new antimicrobial molecules encouraged us to carried out this study. The antibacterial effect of δ-endotoxines produced by two Bt stains; a strain isolated from soil at northern of Algeria (Bt 7.2.B), and a strain isolated from a bioinsecticide (Bacillus thuringiensis var aizawai), activated by proteolysis, was assayed on clinical bacterial strains and ATCC collection ones respectively. Gram positive and negative clinical bacterial strains (Escherichia coli, Klebsiella pneumonaie, Pseudomonas aeruginosa, Staphylococcus aureus) were sensitive to activated Bt 72B endotoxins. Similarly, bacterial strains from ATCC collection (Escherichia coli ATCC 25922, Pseudomonas aerugenosa ATCC 27853, Staphylococcus aureus ATCC 25923) were sensitive to activated B. thuringiensis var aizawai δ-endotoxines. The activated δ-endotoxins were separated by SDS-PAGE.

Keywords: Bacillus thuringiensis, crystals, cry proteins, δ-endotoxins, antibacterial activity

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Authors: Yuko Matayoshi, Takashi Sakai, Yin-Gjum Jin, Jun-ichi Koyama

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To elucidate the material characteristics of single crystals of pure aluminum and copper, the respective relations between crystallographic orientations and micro structures were examined, along with bending and mechanical properties. The texture distribution was also analysed. Bending tests were performed in a SEM apparatus while its behaviors were observed. Some analytical results related to crystal direction maps, inverse pole figures, and textures were obtained from electron back scatter diffraction (EBSD) analyses.

Keywords: pure aluminum, pure copper, single crystal, bending, SEM-EBSD analysis, texture, microstructure

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Authors: Gulsharat A. Baigonakova, Ekaterina S. Marchenko, Venera R. Luchsheva

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The preferred materials for bone grafting are titanium-nickel alloys. They have a porous, permeable structure similar to that of bone tissue, can withstand long-term physiological stress in the body, and retain the scaffolding function for bone tissue ingrowth. Despite the excellent functional properties of these alloys, there is a possibility of post-operative infectious complications that prevent the newly formed bone tissue from filling the spaces created in a timely manner and prolong the rehabilitation period of patients. In order to minimise such consequences, it is necessary to use biocompatible materials capable of simultaneously fulfilling the function of a long-term functioning implant and an osteoreplacement carrier saturated with drugs. Methods to modify the surface by saturation with bioactive substances, in particular macrocyclic compounds, for the controlled release of drugs, biologically active substances, and cells are becoming increasingly important. This work is dedicated to the functionalisation of the surface of porous titanium nickelide by the deposition of macrocyclic compounds in order to provide titanium nickelide with antibacterial activity and accelerated osteogenesis. The paper evaluates the effect of macrocyclic compound deposition methods on the continuity, structure, and cytocompatibility of the surface properties of porous titanium nickelide. Macrocyclic compounds were deposited on the porous surface of titanium nickelide under the influence of various physical effects. Structural research methods have allowed the evaluation of the surface morphology of titanium nickelide and the nature of the distribution of these compounds. The method of surface functionalisation of titanium nickelide influences the size of the deposited bioactive molecules and the nature of their distribution. The surface functionalisation method developed has enabled titanium nickelide to be deposited uniformly on the inner and outer surfaces of the pores, which will subsequently enable the material to be uniformly saturated with various drugs, including antibiotics and inhibitors. The surface-modified porous titanium nickelide showed high biocompatibility and low cytotoxicity in in vitro studies. The research was carried out with financial support from the Russian Science Foundation under Grant No. 22-72-10037.

Keywords: biocompatibility, NiTi, surface, porous structure

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Authors: M. A. Yazdi, J. Yang, L. Yihui, H. Su

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The application of recycle waste tires into civil engineering practices, namely asphalt paving mixtures and cementbased materials has been gaining ground across the world. This review summarizes and compares the recent achievements in the area of plain rubberized concrete (PRC), in details. Different treatment methods have been discussed to improve the performance of rubberized Portland cement concrete. The review also includes the effects of size and amount of tire rubbers on mechanical and durability properties of PRC. The microstructure behaviour of the rubberized concrete was detailed.

Keywords: waste rubber aggregates, microstructure, treatment methods, size and content effects

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Authors: Asiya Rezzouq, Mehdi El Bouchti, Omar Cherkaoui, Sanaa Majid, Souad Zyade

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In recent years, there has been a steady increase in the exploration of new renewable and non-conventional sources for the production of biodegradable nanomaterials. Nature harbours valuable cellulose-rich materials that have so far been under-exploited and can be used to create cellulose derivatives such as cellulose microfibres (CMFs) and cellulose nanocrystals (CNCs). These unconventional sources have considerable potential as alternatives to conventional sources such as wood and cotton. By using agricultural waste to produce these cellulose derivatives, we are responding to the global call for sustainable solutions to environmental and economic challenges. Responsible management of agricultural waste is increasingly crucial to reducing the environmental consequences of its disposal, including soil and water pollution, while making efficient use of these untapped resources. In this study, the main objective was to extract cellulose nanocrystals (CNC) from melon plant residues using methods that are both efficient and sustainable. To achieve this high-quality extraction, we followed a well-defined protocol involving several key steps: pre-treatment of the residues by grinding, filtration and chemical purification to obtain high-quality (CMF) with a yield of 52% relative to the initial mass of the melon plant residue. Acid hydrolysis was then carried out using phosphoric acid and sulphuric acid to convert (CMF) into cellulose nanocrystals. The extracted cellulose nanocrystals were subjected to in-depth characterization using advanced techniques such as transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction. The resulting cellulose nanocrystals have exceptional properties, including a large specific surface area, high thermal stability and high mechanical strength, making them suitable for a variety of applications, including as reinforcements for composite materials. In summary, the study highlights the potential for recovering agricultural melon waste to produce high-quality cellulose nanocrystals with promising applications in industry, nanotechnology, and biotechnology, thereby contributing to environmental and economic sustainability.

Keywords: cellulose, melon plant residues, cellulose nanocrystals, properties, applications, composite materials

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Authors: Guilherme Henrique Gabriel, Lucí Hidalgo Nunes

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An important feature of rainfall regimes is the variability, which is subject to the atmosphere’s general and regional dynamics, geographical position and relief. Despite being inherent to the climate system, it can harshly impact virtually all human activities. In turn, global climate change has the ability to significantly affect smaller-scale rainfall regimes by altering their current variability patterns. In this regard, it is useful to know if regional climates are changing over time and whether it is possible to link these variations to climate change trends observed globally. This study is part of an international project (Metropole-FAPESP, Proc. 2012/51876-0 and Proc. 2015/11035-5) and the objective was to identify and evaluate possible changes in rainfall behavior in the state of São Paulo, southeastern Brazil, using rainfall data from 79 rain gauges for the last forty years. Cluster analysis and gamma distribution parameters were used for evaluating spatial and temporal trends, and the outcomes are presented by means of geographic information systems tools. Results show remarkable changes in rainfall distribution patterns in São Paulo over the years: changes in shape and scale parameters of gamma distribution indicate both an increase in the irregularity of rainfall distribution and the probability of occurrence of extreme events. Additionally, the spatial outcome of cluster analysis along with the gamma distribution parameters suggest that changes occurred simultaneously over the whole area, indicating that they could be related to remote causes beyond the local and regional ones, especially in a current global climate change scenario.

Keywords: climate change, cluster analysis, gamma distribution, rainfall

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Authors: Linh Tong

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This paper aims to contribute to the understanding of key education reforms in Vietnam from 1945 to 2017, which reflects an evolution of socio-political needs of the Socialist Republic of Vietnam throughout this period. It explores the contextual conditions, motivations and ambitions influencing the formation of the education reforms in Vietnam. It also looks, from an applied practical perspective, at the influence of politics on education policy-making. The research methodology includes a content analysis of curriculum designs proposed by the Ministry of Education and Training, relevant resolutions and executive orders passed by the National Assembly and the Prime Minister, as well as interviews with experts and key stakeholders. The results point to a particular configuration of factors which have been inspiring the shape and substance of these reforms and which have most certainly influenced their implementation. This configuration evolves from the immediate needs to erase illiteracy and cultivate socialist economic model at the beginning of Vietnam’s independence in 1945-1975, to a renewed urge to adopt market-oriented economy in 1986 and cautiously communicate with the outside world until 2000s, and to currently a demonstrated desire to fully integrate into the global economy and tackle with rising concerns about national security (the South China Sea Dispute), environmental sustainability, construction of a knowledge economy, and a rule-of-law society. Overall, the paper attempts to map Vietnam’s socio-political needs with the changing sets of goals and expected outcomes in teaching and learning methodologies and practices as introduced in Vietnamese key education reforms.

Keywords: curriculum development, knowledge society, national security, politics of education policy-making, Vietnam's education reforms

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Authors: Mohadeseh Seyednezhad, Armin Rajabi, Andanastui Muchtar, Mahendra Rao Somalu

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This work investigates the electrical properties of NiO-SDC/SDC anode sintered at about 1200 ○C for 1h through a relatively new approach, namely the microwave method. Nano powders Sm0.2Ce0.8O1.9 (SDC) and NiO were mixed by using a high-energy ball-mill and subsequent co-pressed at three different compaction pressures 200, 300 and 400 MPa. The novelty of this study consists in the effect of compaction pressure on the electrochemical performance of Ni-SDC/SDC anode, with no binder used between layers. The electrical behavior of the prepared anode has been studied by electrochemical impedance spectra (EIS) in controlled atmospheres, operating at high temperatures (600-800 °C).

Keywords: sintering, fuel cell, electrical conductivity, nanostructures, impedance spectroscopy, ceramics

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Authors: Mustafa Yılmaz, Ahmet Akar, Nesrin Köken, Nilgün Kızılcan

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Commercially available poly(acrylonitrile-co-vinyl acetate) P(AN-VA) or poly(acrylonitrile-co-methyl acrylate) P(AN-MA) are not satisfactory to meet the demand in flame and fire-resistance. In this work, vinylphosphonic acid is used during polymerization of acrylonitrile, vinyl acetate, methacrylic acid to produce fire-retardant polymers. These phosphorus containing polymers are successfully spun in the form of nanofibers. Properties such as water absorption of polymers are also determined and compared with commercial polymers.

Keywords: flame retardant, nanofiber, polyacrylonitrile, phosphorous compound, membrane

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Authors: Natalie Riley, Anita Quigley, Robert M. I. Kapsa, George W. Greene

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As the fields of medicine and bionics grow rapidly in technological advancement, the future and success of it depends on the ability to effectively interface between the artificial and the biological worlds. The biggest obstacle when it comes to implantable, electronic medical devices, is maintaining a ‘clean’, low noise electrical connection that allows for efficient sharing of electrical information between the artificial and biological systems. Implant fouling occurs with the adhesion and accumulation of proteins and various cell types as a result of the immune response to protect itself from the foreign object, essentially forming an electrical insulation barrier that often leads to implant failure over time. Lubricin (LUB) functions as a major boundary lubricant in articular joints, a unique glycoprotein with impressive anti-adhesive properties that self-assembles to virtually any substrate to form a highly ordered, ‘telechelic’ polymer brush. LUB does not passivate electroactive surfaces which makes it ideal, along with its innate biocompatibility, as a coating for implantable bionic electrodes. It is the aim of the study to investigate LUB’s anti-fouling properties and its potential as a safe, bioinspired material for coating applications to enhance the performance and longevity of implantable medical devices as well as reducing the frequency of implant replacement surgeries. Native, bovine-derived LUB (N-LUB) and recombinant LUB (R-LUB) were applied to gold-coated mylar surfaces. Fibroblast, chondrocyte and neural cell types were cultured and grown on the coatings under both passive and electrically stimulated conditions to test the stability and anti-adhesive property of the LUB coating in the presence of an electric field. Lactate dehydrogenase (LDH) assays were conducted as a directly proportional cell population count on each surface along with immunofluorescent microscopy to visualize cells. One-way analysis of variance (ANOVA) with post-hoc Tukey’s test was used to test for statistical significance. Under both passive and electrically stimulated conditions, LUB significantly reduced cell attachment compared to bare gold. Comparing the two coating types, R-LUB reduced cell attachment significantly compared to its native counterpart. Immunofluorescent micrographs visually confirmed LUB’s antiadhesive property, R-LUB consistently demonstrating significantly less attached cells for both fibroblasts and chondrocytes. Preliminary results investigating neural cells have so far demonstrated that R-LUB has little effect on reducing neural cell attachment; the study is ongoing. Recombinant LUB coatings demonstrated impressive anti-adhesive properties, reducing cell attachment in fibroblasts and chondrocytes. These findings and the availability of recombinant LUB brings into question the results of previous experiments conducted using native-derived LUB, its potential not adequately represented nor realized due to unknown factors and impurities that warrant further study. R-LUB is stable and maintains its anti-fouling property under electrical stimulation, making it suitable for electroactive surfaces.

Keywords: anti-fouling, bioinspired, cell attachment, lubricin

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Authors: Nura Brimo, Dilek Cokeliler Serdaroglu, Tansel Uyar, Busra Uysal, Elif Bahar Cakici, Miris Dikmen, Zerrin Canturk

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Background: A combination of antibiotics, including metronidazole (MET), ciprofloxacin (CIP), and minocycline (MINO), has been demonstrated to disinfect bacteria in necrotic teeth before regenerative processes. It has been presented clinically that antibiotic pastes may drive to possible stem cell death and difficulties in removing from the canal system, which can limit the regenerative procedure. This study was designed to (1) synthesize nanofibrous webs containing various concentrations of different medicaments (triple, double, and calcium hydroxide,Ca(OH)2), and (2) coat thiselectrospun fibrous gutta-percha (GP) cones. Methods: Poly(vinylpyrrolidone) (PVP)-based electrospun fibrous webs were processed with low medicaments concentrations. Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), and X-Ray Photoelectron Spectroscopy (XPS) were carried out to investigate fiber morphology, antibiotic incorporation, and characterized GP-coated fibrous webs, respectively. The chemical and physical properties of dentine were carried out via Fourier Transform Infrared Spectroscopy (FTIR) and Nano-SEM, respectively. The antimicrobial properties of the different fibrous webs were assessed against various bacteria by direct nanofiber/bacteria contact. Cytocompatibility was measured by applying the MTT method. Results: The mean fiber diameter of the experiment groups of medicament-containing fibers ranged in the nm scale and was significantly smaller than PVP fibers. EDX analysis confirmed the presence of medicaments in the nanofibers. XPS analysis presented a complete coating of the fibers with GPs; FTIR and Nano-SEM showed no chemical and physical configuration of intracanal medicaments on the dentine surface. Meanwhile, nanofibrous webs led to a significant reduction in the percentage of viable bacteria compared with the negative control and PVP. Conclusion: Our findings suggest that TA-NFs, DA-NFs, and Cₐ(OH)₂)-NFs coated GP cones have significant potential in eliminating intracanal bacteria, cell-friendly behavior, and clinical usage features.

Keywords: drug delivery, drug carrier, electrospinning, nano/microfibers, regenerative endodontic, morphology

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Authors: Ali Aghahosseini Dehaghani

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Every year in this globalized world, thousands of migrants leave their countries hoping to find a better situation of life in other parts of the world. In this regard, many questions, from a human rights point of view, have been raised about how this phenomenon should be managed in the host countries. Although legal approaches such as legislation and litigation are inevitable in the way to respect the human rights of migrants, there is an increasing consensus about the fact that a strict juridical approach is inadequate to protect as well as to prevent violations of migrants’ rights. Indeed, given the multiplicity of factors that affect and shape the application of these rights and considering the fact that law is a social phenomenon, what is needed is an interdisciplinary approach, which combines both juridical approaches and perspectives from other disciplines. In this respect, a sociological approach is important because it shows the social processes through which human rights of migrants have been constructed or violated in particular social situations. Sociologists who study international migration ask the questions such as how many people migrate, who migrates, why people migrate, what happens to them once they arrive in the host country, how migration affects sending and receiving communities, the extent to which migrants help the economy, the effects of migration on crimes, and how migrants change the local communities. This paper is an attempt to show how sociology can promote human rights of migrants. To this end, the article first explores the usefulness and value of an interdisciplinary approach to realize how and to what extent sociology may improve and promote the human rights of migrants in the destination country. It then examines mechanisms which help to reach to a systematic integration of law and sociological discipline to advance migrants’ rights as well as to encourage legal scholars to consider the implications of societal structures in their works.

Keywords: human rights, migrants, sociological approach, interdisciplinary study

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Authors: Arezoo Hakimi, Afshin Farahbakhsh

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Herein, we comparison synthesized Fe3O4 using, hydrothermal method, Mechanochemical processes and solvent thermal method. The Hydrothermal Technique has been the most popular one, gathering interest from scientists and technologists of different disciplines, particularly in the last fifteen years. In the hydrothermal method Fe3O4 microspheres, in which many nearly monodisperse spherical particles with diameters of about 400nm, in the mechanochemical method regular morphology indicates that the particles are well crystallized and in the solvent thermal method Fe3O4 nanoparticles have good properties of uniform size and good dispersion.

Keywords: Fe3O4 nanoparticles, hydrothermal method, mechanochemical processes, solvent thermal method

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Authors: Anissa Mary Thomas Thattil, Nancy Angeline Gnanaselvam, B. Ramakrishna Goud

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Faecal sludge management (FSM) is an unorganized sector, and in India, there is an absence of regulations regarding the collection, transport, treatment, and disposal of faecal sludge. FSM has a high degree of occupational hazards that need to be thoroughly understood in order to shape effective solutions. On-field observations of five FSM operations were conducted in Anekal Taluk of southern Karnataka. All five of the FSM operations were privately owned and snowball method of sampling was employed. Two types of FS operations observed were: mechanical emptying involving direct human contact with faecal sludge and mechanical emptying without direct human contact with faecal sludge. Each operation was manned by 3-4 faecal sludge operators (FSOs). None of the observed FSOs used personal protective equipment. According to the WHO semi-quantitative risk assessment, the very high risk occupational hazards identified were dermal contact with faecal sludge, inhalation of toxic gases, and social stigma. The high risk hazards identified were trips and falls, injuries, ergonomic hazards, substance abuse, and mental health problems. In all five FSM operations, the collected faecal sludge was discharged untreated onto abandoned land. FSM in India is fraught with occupational and environmental hazards which need to be urgently addressed. This includes formalizing the institution of FSM, contextualized behaviour change communication, capacity building of local bodies, awareness programmes among agriculturists and FSOs, and designation of sites for the safe harnessing of faecal sludge as soil nutrient.

Keywords: faecal sludge, faecal sludge management, FSM, occupational hazards, sanitation

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Authors: Mehrzad Mohabbi Yadollahi, Pouneh Abdollahifard, Behzad Mokhtare, Majid Atashafrazeh

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Geopolymers are believed to provide good fire resistance. The effects of elevated temperatures on mechanical and microstructural properties of pumice-based geopolymer were investigated in this study. Pumice based geopolymer was exposed to elevated temperatures of 200, 400, 600, and 800 ºC for 3 hours. The residual strength of these specimens was determined after cooling at room temperature and microstructures of these samples were investigated by FTIR and SEM analyses. Specimens which were initially grey turned reddish accompanied by the appearance of cracks as temperatures increased to 600 and 800 ºC.

Keywords: geopolymer, pumice, elevated temperature, SEM, FTIR

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Authors: Omar Alhamd, Peter A. Thomas, Trevor J. Greenhough, Annette K. Shrive

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The Pseudomonas syringae species complex includes many plant pathogenic strains with highly specific interactions with varied host species and cultivars. The rapid spread of these bacteria over the last ten years has become a cause for concern. Nanoparticles have previously shown promise in microbiological action. We have therefore investigated in vitro and in vivo the effects of different types and sizes of nanoparticles in order to provide quantitative information about their effect on the bacteria. The effects of several different nanoparticles against several bacteria strains were investigated. The effect of NP on bacterial growth was studied by measuring the optical density, biochemical and nutritional tests, and transmission electron microscopy (TEM) to determine the shape and size of NP. Our results indicate that their effects varied, with either a negative or a positive impact on both bacterial and plant growth. Additionally, the methods of exposure to nanoparticles have a crucial role in accumulation, translocation, growth response and bacterial growth. The results of our studies on the behaviour and effects of nanoparticles in model plants showed. Cerium oxide (CeO₂) and silver (Ag) NP showed significant antibacterial activity against several pathogenic bacteria. It was found that titanium nanoparticles (TiO₂) can have either a negative or a positive impact, according to concentration and size. It is also thought that environmental conditions can have a major influence on bacterial growth. Studies were therefore also carried out under some environmental stress conditions to test bacterial survival and to assess bacterial virulence. All results will be presented including information about the effects of different nanoparticles on Pseudomonas syringae bacteria.

Keywords: plant microbiome, nanoparticles, 16S rRNA gene sequencing, bacterial survival

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Authors: Y. Landkocz, C. Lepers, P.J. Martin, B. Fougère, F. Roy Saint-Georges. A. Verdin, F. Cazier, F. Ledoux, D. Courcot, F. Sichel, P. Gosset, P. Shirali, S. Billet

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In 2013, the International Agency for Research on Cancer (IARC) classified air pollution and fine particles as carcinogenic to humans. Causal relationships exist between elevated ambient levels of airborne particles and increase of mortality and morbidity including pulmonary diseases, like lung cancer. However, due to a double complexity of both physicochemical Particulate Matter (PM) properties and tumor mechanistic processes, mechanisms of action remain not fully elucidated. Furthermore, because of several common properties between air pollution PM and tobacco smoke, like the same route of exposure and chemical composition, potential mechanisms of synergy could exist. Therefore, smoking could be an aggravating factor of the particles toxicity. In order to identify some mechanisms of action of particles according to their size, two samples of PM were collected: PM0.03 2.5 and PM0.33 2.5 in the urban-industrial area of Dunkerque. The overall cytotoxicity of the fine particles was determined on human bronchial cells (BEAS-2B). Toxicological study focused then on the metabolic activation of the organic compounds coated onto PM and some genetic and epigenetic changes induced on a co-culture model of BEAS-2B and alveolar macrophages isolated from bronchoalveolar lavages performed in smokers and non-smokers. The results showed (i) the contribution of the ultrafine fraction of atmospheric particles to genotoxic (eg. DNA double-strand breaks) and epigenetic mechanisms (eg. promoter methylation) involved in tumor processes, and (ii) the influence of smoking on the cellular response. Three main conclusions can be discussed. First, our results showed the ability of the particles to induce deleterious effects potentially involved in the stages of initiation and promotion of carcinogenesis. The second conclusion is that smoking affects the nature of the induced genotoxic effects. Finally, the in vitro developed cell model, using bronchial epithelial cells and alveolar macrophages can take into account quite realistically, some of the existing cell interactions existing in the lung.

Keywords: air pollution, fine and ultrafine particles, genotoxic and epigenetic alterations, smoking

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Authors: M. Ghasemi-Varnamkhasti, S. H. Yoosefian. A. Mohammad- Razdari

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The effect of 1.0 kJ/m² Ultraviolet-C (UV-C) light on pH, weight loss, color, and firmness of button mushroom (Agaricus bisporus) tissues during 21-days storage at 4 ºC was studied. UV-C irradiation enhanced pH, weight, color parameters, and firmness of mushroom during storage compared to control treatment. However, application of 1.0 kJ/m² UV-C treatment could effectively induce the increase of weight loss, firmness, and pH to 14.53%, 49.82%, and 10.39%, respectively. These results suggest that the application of UV-C irradiation could be an effective method to maintain the postharvest quality of mushrooms.

Keywords: mushroom, polyethylene film, quality, UV-c irradiation

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Authors: S. Fröhlich, M. Herold, M. Allmer

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Early stage quantitative analysis of host cell protein (HCP) variations is challenging yet necessary for comprehensive bioprocess development. High resolution mass spectrometry (HRMS) provides a high-end technology for accurate identification alongside with quantitative information. Hereby we describe a flexible HRMS assay platform to quantify HCPs relevant in microbial expression systems such as E. Coli in both up and downstream development by means of MVDA tools. Cell pellets were lysed and proteins extracted, purified samples not further treated before applying the SMART tryptic digest kit. Peptides separation was optimized using an RP-UHPLC separation platform. HRMS-MSMS analysis was conducted on an Orbitrap Velos Elite applying CID. Quantification was performed label-free taking into account ionization properties and physicochemical peptide similarities. Results were analyzed using SIEVE 2.0 (Thermo Fisher Scientific) and SIMCA (Umetrics AG). The developed HRMS platform was applied to an E. Coli expression set with varying productivity and the corresponding downstream process. Selected HCPs were successfully quantified within the fmol range. Analysing HCP networks based on pattern analysis facilitated low level quantification and enhanced validity. This approach is of high relevance for high-throughput screening experiments during upstream development, e.g. for titer determination, dynamic HCP network analysis or product characterization. Considering the downstream purification process, physicochemical clustering of identified HCPs is of relevance to adjust buffer conditions accordingly. However, the technology provides an innovative approach for label-free MS based quantification relying on statistical pattern analysis and comparison. Absolute quantification based on physicochemical properties and peptide similarity score provides a technological approach without the need of sophisticated sample preparation strategies and is therefore proven to be straightforward, sensitive and highly reproducible in terms of product characterization.

Keywords: process analytical technology, mass spectrometry, process characterization, MVDA, pattern recognition

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Authors: Siriporn Okonogi, Pimpak Phumat, Sakornrat Khongkhunthian

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Piper betle has been extensively reported for various pharmacological effects including antimicrobial activity. 4-Allylpyrocatechol (AC) is a principle active compound found in P. betle. However, AC has a problem of solubility in water. The aims of the present study were to prepare AC loaded polymeric micelles for enhancing its water solubility and to evaluate its anti-biofilm activity against oral phathogenic bacteria. AC was loaded in polymeric micelles (PM) of Pluronic F127 by using thin film hydration method to obtain AC loaded PM (PMAC). The results revealed that AC in the form of PMAC possessed high water solubility. PMAC particles were characterized using a transmission electron microscope and photon correlation spectroscopy. Determination of entrapment efficiency (EE) and loading capacity (LC) of PMAC was done by using high-performance liquid chromatography. The highest EE (86.33 ± 14.27 %) and LC (19.25 ± 3.18 %) of PMAC were found when the weight ratio of polymer to AC was 4 to 1. At this ratio, the particles showed spherical in shape with the size of 38.83 ± 1.36 nm and polydispersity index of 0.28 ± 0.10. Zeta potential of the particles is negative with the value of 16.43 ± 0.55 mV. Crystal violet assay and confocal microscopy were applied to evaluate the effects of PMAC on Streptococcus mutans biofilms using chlorhexidine (CHX) as a positive control. PMAC contained 1.5 mg/mL AC could potentially inhibit (102.01 ± 9.18%) and significantly eradicate (85.05 ± 2.03 %) these biofilms (p < 0.05). Comparison with CHX, PMAC showed slightly similar biofilm inhibition but significantly stronger biofilm eradication (p < 0.05) than CHX. It is concluded that PMAC can enhance water solubility and anti-biofilm activity of AC.

Keywords: pluronic, polymeric micelles, solubility, 4-allylpyrocathecol, Streptococcus mutans, anti-biofilm

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Authors: Zohreh Soleimani, Sally Salome Shahzad, Stamatis Zoras

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As a result of current energy and environmental issues, the human body is known as one of the promising candidate for converting wasted heat to electricity (Seebeck effect). Thermoelectric generator (TEG) is one of the most prevalent means of harvesting body heat and converting that to eco-friendly electrical power. However, the uneven distribution of the body heat and its curvature geometry restrict harvesting adequate amount of energy. To perfectly transform the heat radiated by the body into power, the most direct solution is conforming the thermoelectric generators (TEG) with the arbitrary surface of the body and increase the temperature difference across the thermoelectric legs. Due to this, a computational survey through COMSOL Multiphysics is presented in this paper with the main focus on the impact of integrating a flexible wearable TEG with a corrugated shaped heat sink on the module power output. To eliminate external parameters (temperature, air flow, humidity), the simulations are conducted within indoor thermal level and when the wearer is stationary. The full thermoelectric characterization of the proposed TEG fabricated by a wavy shape heat sink has been computed leading to a maximum power output of 25µW/cm2 at a temperature gradient nearly 13°C. It is noteworthy that for the flexibility of the proposed TEG and heat sink, the applicability and efficiency of the module stay high even on the curved surfaces of the body. As a consequence, the results demonstrate the superiority of such a TEG to the most state of the art counterparts fabricated with no heat sink and offer a new train of thought for the development of self-sustained and unobtrusive wearable power suppliers which generate energy from low grade dissipated heat from the body.

Keywords: device simulation, flexible thermoelectric module, heat sink, human body heat

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Authors: S. J. Bindhu, Edwina G. Rodrigues, Jijo Balakrishnan

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A grid-connected photovoltaic (PV) micro inverter with good performance properties is proposed in this paper. The proposed inverter with a quadrupler, having more efficiency and less voltage stress across the diodes. The stress that come across the diodes that use in the inverter section is considerably low in the proposed converter, also the protection scheme that we provided can eliminate the chances of the error due to fault. The proposed converter is implemented using perturb and observe algorithm so that the fluctuation in the voltage can be reduce and can attain maximum power point. Finally, some simulation and experimental results are also presented to demonstrate the effectiveness of the proposed converter.

Keywords: DC-DC converter, MPPT, quadrupler, PV panel

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Authors: Yanin Hosakun, Sujitra Wongkasemjit, Thanyalak Chaisuwan

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Carbon dioxide removal from natural gas is an important process because the existence of carbon dioxide in natural gas contributes to pipeline corrosion, reduces the heating value, and takes up volume in the pipeline. In this study, bacterial cellulose was chosen for the CO2/CH4 gas separation membrane due to its unique structure and prominent properties. Additionally, it can simply be obtained by culturing the bacteria so called “Acetobacter xylinum” through fermentation of coconut juice. Bacterial cellulose membranes with and without silver ions were prepared and studied for the separation performance of CO2 and CH4.

Keywords: bacterial cellulose, CO2, CH4 separation, membrane, nata de coco

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Authors: R. Gounina-Allouane, N. Ouali, F. Z. Berrabah, A. Bentaleb

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For a long time, the Gram-positive spore-forming bacteria Bacillus thuringiensis (Bt) has been widely used in biological control against devastating and disease vectors insects. This is due to the insecticidal activity of its crystalline parasporal inclusion (crystals) predominantly comprised of one or more proteins (Cry and Cyt proteins) also called δ-endotoxins, produced during sporulation. The shape and composition of Bt crystals vary among strains and crystalline proteins are extremely varied (more than 475 cry gene were discovered). The insecticidal activity of Bt crystals is very well studied, thus their insecticidal mode of action is well established, however, their antimicrobial effect is largely unknown. The lack of data on the antimicrobial effect of crystalline proteins of Bt and the need for searching new antimicrobial molecules encouraged us to carried out this study. The antibacterial effect of δ-endotoxines produced by two Bt stains; a strain isolated from soil at northern of Algeria (Bt 7.2.B), and a strain isolated from a bioinsecticide (Bacillus thuringiensis var aizawai), activated by proteolysis, was assayed on clinical bacterial strains and ATCC collection ones respectively. Gram positive and negative clinical bacterial strains (Escherichia coli, Klebsiella pneumonaie, Pseudomonas aeruginosa, Staphylococcus aureus) were sensitive to activated Bt 72B endotoxins. Similarly, bacterial strains from ATCC collection (Escherichia coli ATCC 25922, Pseudomonas aerugenosa ATCC 27853, Staphylococcus aureus ATCC 25923) were sensitive to activated B. thuringiensis var aizawai δ-endotoxines. The activated δ-endotoxins were separated by SDS-PAGE.

Keywords: Bacillus thuringiensis, crystals, cry proteins, δ-endotoxins, antibacterial activity

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Authors: Sangwoo Oh, Jaewoo Kim, Dongmin Seo, Jaewon Park, Yongha Hwang, Sungkyu Seo

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Plasmonics has been regarded one of the most powerful bio-sensing modalities to evaluate bio-molecular interactions in real-time. However, most of the plasmonic sensing methods are based on labeling metallic nanoparticles, e.g. gold or silver, as optical modulation markers, which are non-recyclable and expensive. This plasmonic modulation can be usually achieved through various nano structures, e.g., nano-hole arrays. Among those structures, plasmonic lens has been regarded as a unique plasmonic structure due to its light focusing characteristics. In this study, we introduce a custom designed plasmonic lens array for bio-sensing, which was simulated by finite-difference-time-domain (FDTD) approach and fabricated by top-down approach. In our work, we performed the FDTD simulations of various plasmonic lens designs for bacteria sensor, i.e., Samonella and Hominis. We optimized the design parameters, i.e., radius, shape, and material, of the plasmonic lens. The simulation results showed the change in the peak intensity value with the introduction of each bacteria and antigen i.e., peak intensity 1.8711 a.u. with the introduction of antibody layer of thickness of 15nm. For Salmonella, the peak intensity changed from 1.8711 a.u. to 2.3654 a.u. and for Hominis, the peak intensity changed from 1.8711 a.u. to 3.2355 a.u. This significant shift in the intensity due to the interaction between bacteria and antigen showed a promising sensing capability of the plasmonic lens. With the batch processing and bulk production of this nano scale design, the cost of biological sensing can be significantly reduced, holding great promise in the fields of clinical diagnostics and bio-defense.

Keywords: plasmonic lens, FDTD, fabrication, bacteria sensor, salmonella, hominis

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Authors: Sami Khan, Kripa Varanasi

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Corrosion is a widespread problem in several industries and developing surfaces that resist corrosion has been an area of interest since the last several decades. Superhydrophobic surfaces that combine hydrophobic coatings along with surface texture have been shown to improve corrosion resistance by creating voids filled with air that minimize the contact area between the corrosive liquid and the solid surface. However, these air voids can incorporate corrosive liquids over time, and any mechanical faults such as cracks can compromise the coating and provide pathways for corrosion. As such, there is a need for self-healing corrosion-resistance surfaces. In this work, the anti-corrosion properties of textured surfaces impregnated with a lubricant have been systematically studied. Since corrosion resistance depends on the area and physico-chemical properties of the material exposed to the corrosive medium, lubricant-impregnated surfaces (LIS) have been designed based on the surface tension, viscosity and chemistry of the lubricant and its spreading coefficient on the solid. All corrosion experiments were performed in a standard three-electrode cell using iron, which readily corrodes in a 3.5% sodium chloride solution. In order to obtain textured iron surfaces, thin films (~500 nm) of iron were sputter-coated on silicon wafers textured using photolithography, and subsequently impregnated with lubricants. Results show that the corrosion rate on LIS is greatly reduced, and offers an over hundred-fold improvement in corrosion protection. Furthermore, it is found that the spreading characteristics of the lubricant are significant in ensuring corrosion protection: a spreading lubricant (e.g., Krytox 1506) that covers both inside the texture, as well as the top of the texture, provides a two-fold improvement in corrosion protection as compared to a non-spreading lubricant (e.g., Silicone oil) that does not cover texture tops. To enhance corrosion protection of surfaces coated with a non-spreading lubricant, pyramid-shaped textures have been developed that minimize exposure to the corrosive solution, and a consequent twenty-fold increased in corrosion protection is observed. An increase in viscosity of the lubricant scales with greater corrosion protection. Finally, an equivalent cell-circuit model is developed for the lubricant-impregnated systems using electrochemical impedance spectroscopy. Lubricant-impregnated surfaces find attractive applications in harsh corrosive environments, especially where the ability to self-heal is advantageous.

Keywords: lubricant-impregnated surfaces, self-healing surfaces, wettability, nano-engineered surfaces

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Authors: Joseph George, Anne Kotteswara Roa

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Skin disease is one of the most common and popular kinds of health issues faced by people nowadays. Skin cancer (SC) is one among them, and its detection relies on the skin biopsy outputs and the expertise of the doctors, but it consumes more time and some inaccurate results. At the early stage, skin cancer detection is a challenging task, and it easily spreads to the whole body and leads to an increase in the mortality rate. Skin cancer is curable when it is detected at an early stage. In order to classify correct and accurate skin cancer, the critical task is skin cancer identification and classification, and it is more based on the cancer disease features such as shape, size, color, symmetry and etc. More similar characteristics are present in many skin diseases; hence it makes it a challenging issue to select important features from a skin cancer dataset images. Hence, the skin cancer diagnostic accuracy is improved by requiring an automated skin cancer detection and classification framework; thereby, the human expert’s scarcity is handled. Recently, the deep learning techniques like Convolutional neural network (CNN), Deep belief neural network (DBN), Artificial neural network (ANN), Recurrent neural network (RNN), and Long and short term memory (LSTM) have been widely used for the identification and classification of skin cancers. This survey reviews different DL techniques for skin cancer identification and classification. The performance metrics such as precision, recall, accuracy, sensitivity, specificity, and F-measures are used to evaluate the effectiveness of SC identification using DL techniques. By using these DL techniques, the classification accuracy increases along with the mitigation of computational complexities and time consumption.

Keywords: skin cancer, deep learning, performance measures, accuracy, datasets

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Authors: Blessing Ojeme, Frederick Quinn, Russell Karls, Shannon Quinn

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The detection and segmentation of mitochondria from fluorescence microscopy are crucial for understanding the complex structure of the nervous system. However, the constant fission and fusion of mitochondria and image distortion in the background make the task of detection and segmentation challenging. In the literature, a number of open-source software tools and artificial intelligence (AI) methods have been described for analyzing mitochondrial images, achieving remarkable classification and quantitation results. However, the availability of combined expertise in the medical field and AI required to utilize these tools poses a challenge to its full adoption and use in clinical settings. Motivated by the advantages of automated methods in terms of good performance, minimum detection time, ease of implementation, and cross-platform compatibility, this study proposes a fully automated framework for the detection and segmentation of mitochondria using both image shape information and descriptive statistics. Using the low-cost, open-source python and openCV library, the algorithms are implemented in three stages: pre-processing, image binarization, and coarse-to-fine segmentation. The proposed model is validated using the mitochondrial fluorescence dataset. Ground truth labels generated using a Lab kit were also used to evaluate the performance of our detection and segmentation model. The study produces good detection and segmentation results and reports the challenges encountered during the image analysis of mitochondrial morphology from the fluorescence mitochondrial dataset. A discussion on the methods and future perspectives of fully automated frameworks conclude the paper.

Keywords: 2D, binarization, CLAHE, detection, fluorescence microscopy, mitochondria, segmentation

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Authors: Saqib Ali

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Sources are classified into two depending upon the factor of reviving. These sources, which cannot be revived into their original shape once they are consumed, are considered as nonrenewable energy resources, i.e., (coal, fuel) Moreover, those energy resources which are revivable to the original condition even after being consumed are known as renewable energy resources, i.e., (wind, solar, hydel) Renewable energy is a cost-effective way to generate clean and green electrical energy Now a day’s majority of the countries are paying heed to energy generation from RES Pakistan is mostly relying on conventional energy resources which are mostly nonrenewable in nature coal, fuel is one of the major resources, and with the advent of time their prices are increasing on the other hand RES have great potential in the country with the deployment of RES greater reliability and an effective power system can be obtained In this thesis, a similar concept is being used and a hybrid power system is proposed which is composed of intermixing of renewable and nonrenewable sources The Source side is composed of solar, wind, fuel cells which will be used in an optimal manner to serve load The goal is to provide an economical, reliable, uninterruptable power supply. This is achieved by optimal controller (PI, PD, PID, FOPID) Optimization techniques are applied to the controllers to achieve the desired results. Advanced algorithms (Particle swarm optimization, Flower Pollination Algorithm) will be used to extract the desired output from the controller Detailed comparison in the form of tables and results will be provided, which will highlight the efficiency of the proposed system.

Keywords: distributed generation, demand-side management, hybrid power system, micro grid, renewable energy resources, supply-side management

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Authors: A. Isahakyan, A. Terzyan, V. Stepanyan, N. Zulumyan, H. Beglaryan

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The involvement of silica hydrogel derived from serpentine minerals (Mg(Fe))6[Si4O10](OH)8 as a source of silicon dioxide in SiO2–NaOH–BaCl2–H2O system results in precipitating via one-hour stirring of boiling suspension such intermediates that on heating up to 800 °C crystallize into the product composed of barium ortho- Ba2SiO4 and metasilicates BaSiO3. Based on the positive results, this approach has been decided to be adapted to inserting europium (III) ions into the structure of the synthesized compounds. Intermediates previously precipitated in silica hydrogel–NaOH–BaCl2–Eu(NO3)3 system via one-hour stirring at room temperature underwent one-hour heat-treatment at different temperatures (6001200 °C). Prior to calcination, the suspension produced in the mixer was heated on a boiling-water bath until a powder-like sample was obtained. When the silica hydrogel was metered, SiO2 content in the silica hydrogel that is 5.8 % was taken into consideration in order to guaranty the molar ratios of both SiO2 to BaO and SiO2 to Na2O equal to 1:2. BaCl2 and Eu(NO3)3 reagents were weighted so that the formation of appropriate compositions was guaranteed. Samples including various concentrations of Eu3+ ions (1.25, 2.5, 3.75, 5, 6.35, 8.65, 10, 17.5, 18.75 and 20 mol%) were synthesized by the described method. Luminescence excitation, emission spectra of the products were recorded on the Agilent Cary Eclipes fluorescence spectrophotometer using Agilent Xenon flash lamp (80 Hz) as the excitation source (scanning rate=30 nm/min, excitation and emission slits width=5 nm, excitation filter set to auto, emission filter set to auto and PMT detector Voltage=800 V). Prior to optical properties measurements, each of the powder samples was put in the solid sample-holder. X-ray powder diffraction (XRPD) measurements were made on the SmartLab SE diffractometer. Emission spectra recorded for all the samples at an excitation wavelength of 394 nm exhibit peaks centered at around 536, 555, 587, 614, 653, 690 and 702.5 nm. The most intensive emission peak is observed at 614nm due to 5D0→7F2 of europium (III) ions transition. Luminescence intensity achieves its maximum for Eu3+ 17.5 mol% and heat-treatment at 1200 °C. The XRPD patterns revealed that the diffraction peaks recorded for this sample are identical to NaBa6Nd(SiO4)4 reflections. As Nd-containing reagents were not involved into the synthesis, the maximum luminescent intensity is most likely to be conditioned by NaBa6Eu(SiO4)4 formation whose reflections are not available in the ICDD-JCPDS database of crystallographic 2024. Up to Eu3+ 2.5 mol% the samples demonstrate the phases corresponding to Ba2SiO4 and BaSiO3 standards. Subsequent increasing of europium (III) concentration in the system leads to NaBa6Eu(SiO4)4 formation along with Ba2SiO4 and BaSiO3. NaBa6Eu(SiO4)4 share gradually increases and starting from 17.5 mol% and more NaBa6Eu(SiO4)4 phase is only registered. Thus, the variation of europium (III) concentration in silica hydrogel–NaOH–BaCl2–Eu(NO3)3 system allows producing by the precipitation method the products composed of europium (III)-doped Ba2SiO4 and BaSiO3 and/or NaBa6Eu(SiO4)4 distinguished by different luminescent properties. The work was supported by the Science Committee of RA, in the frames of the research projects № 21T-1D131 and № 21SCG-1D013.

Keywords: europium (III)-doped barium ortho- Ba2SiO4 and metasilicates BaSiO₃, NaBa₆Eu(SiO₄)₄, luminescence, precipitation method

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