106 research outputs found

    Does It Make a Difference? L2 Vocabulary Learning via Mobile and Conventional Mode

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    The present study investigated the significance of mobile learning (m-learning) of English vocabulary items through a traditional contrasted with a blended method of content representation. To achieve the goals, sixty semi-illiterate adults were evaluated for their knowledge of the English alphabet and then randomly placed in two groups: traditional (G1) and the blended group (G2). Next, they were presented thirty new English vocabulary items through the two methods. Also, the vocabulary items were taught with and without pictorial annotations. Upon the completion of teaching, the participants took the paper-and-pencil-based English Vocabulary Recognition and Recall (EVRR) test. The test results were subjected to the appropriate statistical analyses. The analysis demonstrated the supremacy of blended group's performance over the traditional group in vocabulary learning. Furthermore, the obtained results confirmed that pictorial annotations enhanced the learning of L2 vocabulary compared with non-annotated items. The results can provide some practical and theoretical implications for both teachers and learners

    Designing a Reverse Logistics Network for End-of-Life Vehicles Recovery

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    The environmental factors are receiving increasing attention in different life cycle stages of products. When a product reaches its End-Of-Life (EOL) stage, the management of its recovery process is affected by the environmental and also economical factors. Selecting efficient methods for the collection and recovery of EOL products has become an important issue. The European Union Directive 2000/53/EC extends the responsibility of the vehicle manufacturers to the postconsumer stage of the vehicle. In order to fulfill the requirements of this Directive and also efficient management of the whole recovery process, the conceptual framework of a reverse logistics network is presented. The distribution of new vehicles in an area and also collecting the End-of-Life Vehicles (ELVs) and their recovery are considered jointly. It is assumed that the new vehicles distributors are also responsible for collecting the ELVs. Then a mathematical model is developed which minimizes the costs of setting up the network and also the relevant transportation costs. Because of the complexity of the model, a solution methodology based on the genetic algorithm is designed which enables achieving good quality solutions in a reasonable algorithm run time

    Profiling and quantitative evaluation of three Nickel-Coated magnetic matrices for purification of recombinant proteins: lelpful hints for the optimized nanomagnetisable matrix preparation

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    <p>Abstract</p> <p>Background</p> <p>Several materials are available in the market that work on the principle of protein magnetic fishing by their histidine (His) tags. Little information is available on their performance and it is often quoted that greatly improved purification of histidine-tagged proteins from crude extracts could be achieved. While some commercial magnetic matrices could be used successfully for purification of several His-tagged proteins, there are some which have been proved to operate just for a few extent of His-tagged proteins. Here, we address quantitative evaluation of three commercially available Nickel nanomagnetic beads for purification of two His-tagged proteins expressed in <it>Escherichia coli </it>and present helpful hints for optimized purification of such proteins and preparation of nanomagnetisable matrices.</p> <p>Results</p> <p>Marked differences in the performance of nanomagnetic matrices, principally on the basis of their specific binding capacity, recovery profile, the amount of imidazole needed for protein elution and the extent of target protein loss and purity were obtained. Based on the aforesaid criteria, one of these materials featured the best purification results (SiMAG/N-NTA/Nickel) for both proteins at the concentration of 4 mg/ml, while the other two (SiMAC-Nickel and SiMAG/CS-NTA/Nickel) did not work well with respect to specific binding capacity and recovery profile.</p> <p>Conclusions</p> <p>Taken together, functionality of different types of nanomagnetic matrices vary considerably. This variability may not only be dependent upon the structure and surface chemistry of the matrix which in turn determine the affinity of interaction, but, is also influenced to a lesser extent by the physical properties of the protein itself. Although the results of the present study may not be fully applied for all nanomagnetic matrices, but provide a framework which could be used to profiling and quantitative evaluation of other magnetisable matrices and also provide helpful hints for those researchers facing same challenge.</p

    A Fault Detection Scheme for Islanded-Microgrid with Grid-Forming Inverters

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    Contribution to Mobile-Enhanced English Language Pedagogy among Iranian L2 Learners

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    This study aimed at providing learners with an opportunity not only to bring together their core and disciplinary knowledge to acquire major skills of learning English as a foreign language (EFL), and the intellectual challenge of these issues at the interface of media, language and religion, but also help the materials generators to produce suitable types of content to be delivered through the medium of mobile technology. Therefore, it sought to examine the new way of teaching EFL in the form of correspondence with respect to Iranian learners' native culture and language. For the purposes of this study, English was the target language for 680 Iranian students with pre-intermediate level of language proficiency whose native languages were Persian, Arabic, Georgian, and Turkish. This study took as its point of departure the existence of important differences between the two learning materials (off the shelf vs. Islamic culture) types; thus, applying the Qur'ānic criteria of intelligence, knowledge and virtue parallel with the digital representation of common textbook materials, materials delivery was adapted to the cellphone screen to be accessed by learners' in 18 virtual sessions. Learners took part in two summative and 18 formative components included in the assessment design of this study. Also, they all answered a questionnaire which yielded information concerning their attitude towards the target language, and learning through the wireless technology. Learners' short texting correspondence as well as their performance in battery and their answers to items of questionnaires formed the reference for analyzing the results. The gains from English Islamic materials were outweighed by the effects of obtaining materials which involved more categorized cases

    Control of Grid-Following Inverters under Unbalanced Grid Conditions

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    Sensitivity to Antibiotics of Bacteria Exposed to Gamma Radiation Emitted from Hot Soils of the High Background Radiation Areas of Ramsar, Northern Iran

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    Background: Over the past several years our laboratories have investigated different aspects of the challenging issue of the alterations in bacterial susceptibility to antibiotics induced by physical stresses. Objective: To explore the bacterial susceptibility to antibiotics in samples of Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium), Staphylococcus aureus, and Klebsiella pneumoniae after exposure to gamma radiation emitted from the soil samples taken from the high background radiation areas of Ramsar, northern Iran. Methods: Standard Kirby-Bauer test, which evaluates the size of the zone of inhibition as an indicator of the susceptibility of different bacteria to antibiotics, was used in this study. Results: The maximum alteration of the diameter of inhibition zone was found for K. pneumoniae when tested for ciprofloxacin. In this case, the mean diameter of no growth zone in non-irradiated control samples of K. pneumoniae was 20.3 (SD 0.6) mm; it was 14.7 (SD 0.6) mm in irradiated samples. On the other hand, the minimum changes in the diameter of inhibition zone were found for S. typhimurium and S. aureus when these bacteria were tested for nitrofurantoin and cephalexin, respectively. Conclusion: Gamma rays were capable of making significant alterations in bacterial susceptibility to antibiotics. It can be hypothesized that high levels of natural background radiation can induce adaptive phenomena that help microorganisms better cope with lethal effects of antibiotics

    Synthesis of biological based hennotannic acid-based salts over porous bismuth coordination polymer with phosphorous acid tags

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    In this paper, a novel porous polymer capable of coordinating to bismuth (PCPs-Bi) was synthesized. The Bi-PCPs was then reacted with phosphorous acid to produce a novel polymer PCPs(Bi)N(CH(2)PO(3)H(2))(2) which is shown to act as an efficient and recyclable catalyst. The mentioned catalyst was applied for the efficient synthesis of new mono and bis naphthoquinone-based salts of piperidine and/or piperazine via the reaction of hennotannic acid with various aldehydes, piperidine and/or piperazine, respectively. The structure of the resulting mono and bis substituted piperazine or piperidine-based naphthoquinone salts was thoroughly characterized spectroscopically. The electrochemical behavior of the products was also investigated. The presented protocol has the advantages of excellent yields (82–95%), short reaction times (4–30 min) and simple work-up
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