1,020 research outputs found

    Geometric and structural design of foldable structures

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    p. 2392-2404This paper initially investigates the previous works on foldable structures. Subsequently, generation and geometric (architectural) design of compatible foldable structures with scissor-like elements is formulated for various shapes of barrels with no geometric limitations (free forms) for the purpose of configuration processing. Special cases for configuration processing based on given formulation are studied to obtain different geometries. For example, the division of the sum of the internal angles of duplets leads to different geometries. The method employed for this division could be equal between duplets, according to arithmetic or geometric progression, or using algebraic equations. These methods are used to divide the sum of internal angles and radius of curvature; Corresponding geometries are then created and compared. The method to generate a geometry imposed by architectural requirements is also proposed in this work. Using such ordering, one can create and model free form foldable structures. To provide changeability for geometry of the structure, a special mid-connection (pivot) is proposed and a prototype model is constructed to demonstrate the efficiency. To construct real scale foldable structures, some connections and a simple method to analyze and design of this type of connections are proposed. A graph of maximum displacement vs. height of the structure is illustrated. A design-construct methodology for foldable structures is proposed.Babaei, M.; Sanaei, E. (2010). Geometric and structural design of foldable structures. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/728

    Genetic variability of Taenia saginata inferred from mitochondrial DNA sequences

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    Taenia saginata is an important tapeworm, infecting humans in many parts of the world. The present study was undertaken to identify inter- and intraspecific variation of T. saginata isolated from cattle in different parts of Iran using two mitochondrial CO1 and 12S rRNA genes. Up to 105 bovine specimens of T. saginata were collected from 20 slaughterhouses in three provinces of Iran. DNA were extracted from the metacestode Cysticercus bovis. After PCR amplification, sequencing of CO1 and 12S rRNA genes were carried out and two phylogenetic analyses of the sequence data were generated by Bayesian inference on CO1 and 12S rRNA sequences. Sequence analyses of CO1 and 12S rRNA genes showed 11 and 29 representative profiles respectively. The level of pairwise nucleotide variation between individual haplotypes of CO1 gene was 0.3–2.4 % while the overall nucleotide variation among all 11 haplotypes was 4.6 %. For 12S rRNA sequence data, level of pairwise nucleotide variation was 0.2–2.5 % and the overall nucleotide variation was determined as 5.8 % among 29 haplotypes of 12S rRNA gene. Considerable genetic diversity was found in both mitochondrial genes particularly in 12S rRNA gene. © 2015, Springer-Verlag Berlin Heidelberg

    Designing a Model for Knowledge Socialization Using Sociability Processes of Human Resource Management: A Case Study

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    This study develops a model for knowledge socialization using sociability processes of human resources through an applied research approach. Two types of participants participated in this study. The first type included academic and industrial experts; the second type included employees and managers of Ansar Bank. Ten experts were asked to identify criteria and weigh the identified criteria. Using simple random sampling, the sample size was estimated at 207. Field and archival studies were used to collect data. Validity and reliability of the distributed questionnaire were confirmed by organizational experts. Using theoretical literature and surveying experts, 18 criteria were identified of which 12 criteria (desirable and joyful workplace, management and leadership support in sociability process, training courses, transparency in working relations, team work, organizational trustful climate, job description and job knowledge, tangible incentives, participatory system, informal technique, defined career path, individual values aligned with organizational value) were selected by screening for prioritization and analysis. Fuzzy AHP and structural equation modelling based on partial least squares were used for prioritization and weighting. Fuzzy AHP model showed that desirable workplace (0.163), participatory systems and brainstorming (0.149), transparency in working relations (0.114), and informal techniques (0.111) gained the highest weights; finally, PLS model showed that all 12 identified criteria were effective on socialization of knowledge management

    Isolation, spectroscopic characterization, X-ray, theoretical studies as well as in vitro cytotoxicity of Samarcandin

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    Samarcandin 1, a natural sesquiterpene-coumarin, was isolated as well as elucidated from F. assa-foetida which has significant effect in Iranian traditional medicine because of its medicinal attitudes. The crystal structure of samarcandin was determined by single-crystal X-ray structure analysis. It is orthorhombic, with unit cell parameters a = 10.8204 (5) Å, b = 12.9894 (7) Å, c = 15.2467 (9) Å, V = 2142.9 (2) Å3, space group P212121 and four symmetry equivalent molecules in the unit cell. Samarcandin was isolated in order to study for its theoretical studies as well as its cellular toxicity as anti-cancer drug against two cancerous cells. In comparison with controls, our microscopic and MTT assay data showed that samarcandin suppresses cancer cell proliferation in a dose-dependent manner with IC50 = 11 μM and 13 for AGS and WEHI-164 cell lines, respectively. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) of the structure was computed by three functional methods and 6-311++G∗∗ standard basis set. The optimized molecular geometry and theoretical analysis agree closely to that obtained from the single crystal X-ray crystallography. To sum up, the good correlations between experimental and theoretical studies by UV, NMR, and IR spectra were found. © 2016 Elsevier Inc. All rights reserved

    Molecular Identification and Sequencing of Mannose Binding Protein (MBP) Gene of Acanthamoeba palestinensis

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    "nBackground: Acanthamoeba keratitis develops by pathogenic Acanthamoeba such as A. pal­es­tinen­sis. Indeed this species is one of the known causative agents of amoebic keratitis in Iran. Mannose Binding Protein (MBP) is the main pathogenicity factors for developing this sight threatening disease. We aimed to characterize MBP gene in pathogenic Acanthamoeba isolates such as A. palestinensis."nMethods: This experimental research was performed in the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran during 2007-2008.  A. palestinensis was grown on 2% non-nutrient agar overlaid with Escherichia coli. DNA extraction was performed using phenol-chloroform method. PCR reaction and amplification were done using specific primer pairs of MBP. The amplified fragment were purified and sequenced. Finally, the obtained fragment was deposited in the gene data bank."nResults: A 900 bp PCR-product was recovered after PCR reaction. Sequence analysis of the purified PCR product revealed a gene with 943 nucleotides. Homology analysis of the ob­tained sequence showed 81% similarity with the available MBP gene in the gene data bank. The fragment was deposited in the gene data bank under accession number EU678895"nConclusion: MBP is known as the most important factor in Acanthamoeba pathogenesis cas­cade. Therefore, characterization of this gene can aid in developing better therapeutic agents and even immunization of high-risk people

    Molecular population study on Penaeus semisulcatus from the Persian Gulf and Oman Sea using cytochrom oxidase subunit I (COI) gene by RFLP method

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    The objective of this investigation was molecular population study on Penaeus semisulcatus stocks from the Persian Gulf and Oman Sea. Samples were collected using trawling method from Hormuz (40 individuals) and Bushehr (35 individuals) regions. The DNA of samples were extracted using phenol and chloroform method and then were simplified using a pair premier of Cytochrom Oxidase Subunit I (COI) gene sequence by a thermal cycler. Nine restriction enzyme were Used to digest the larger gene region that five of them (Alu I, Hinf I, Hinc I I, Hpa I I and Rca I) appeared Polymorphic patterns. Reap software and X^2 test were used to analyses the RFLP data. The average nucleotide diversity arid haplotype diversity among the population were 0.0345720 ± 0.0011952 and 0.28590±0.08174 and nucleotide divergence among population, being studied, is supposed to be 8.5%. Considering the result dispersion of haplotypes in two region showed a significant difference and this is an evidence for proving the variety of the stocks

    Molecular and morphological characterization of the tapeworm Taenia hydatigena (Pallas, 1766) in sheep from Iran

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    Although Taenia hydatigena is one of the most prevalent taeniid species of livestock, very little molecular genetic information exists for this parasite. Up to 100 sheep isolates of T. hydatigena were collected from 19 abattoirs located in the provinces of Tehran, Alborz and Kerman. A calibrated microscope was used to measure the larval rostellar hook lengths. Following DNA extraction, fragments of cytochrome c oxidase 1 (CO1) and 12S rRNA genes were amplified by the polymerase chain reaction method and the amplicons were subjected to sequencing. The mean total length of large and small hooks was 203.4 μm and 135.9 μm, respectively. Forty CO1 and 39 12S rRNA sequence haplotypes were obtained in the study. The levels of pairwise nucleotide variation between individual haplotypes of CO1 and 12S rRNA genes were determined to be between 0.3-3.4% and 0.2-2.1%, respectively. The overall nucleotide variation among all the CO1 haplotypes was 9.7%, and for all the 12S rRNA haplotypes it was 10.1%. A significant difference was observed between rostellar hook morphometry and both CO1 and 12S rRNA sequence variability. A significantly high level of genetic variation was observed in the present study. The results showed that the 12S rRNA gene is more variable than CO1. © 2013 Cambridge University Press

    The Road to Popularity: The Dilution of Growing Audience on Twitter

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    On social media platforms, like Twitter, users are often interested in gaining more influence and popularity by growing their set of followers, aka their audience. Several studies have described the properties of users on Twitter based on static snapshots of their follower network. Other studies have analyzed the general process of link formation. Here, rather than investigating the dynamics of this process itself, we study how the characteristics of the audience and follower links change as the audience of a user grows in size on the road to user's popularity. To begin with, we find that the early followers tend to be more elite users than the late followers, i.e., they are more likely to have verified and expert accounts. Moreover, the early followers are significantly more similar to the person that they follow than the late followers. Namely, they are more likely to share time zone, language, and topics of interests with the followed user. To some extent, these phenomena are related with the growth of Twitter itself, wherein the early followers tend to be the early adopters of Twitter, while the late followers are late adopters. We isolate, however, the effect of the growth of audiences consisting of followers from the growth of Twitter's user base itself. Finally, we measure the engagement of such audiences with the content of the followed user, by measuring the probability that an early or late follower becomes a retweeter
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