14 research outputs found
Development of a robust, low cost stem-loop real-time quantification PCR technique for miRNA expression analysis.
No full textInternational audienceDevelopment of a rapid and accurate quantification method for the detection of microRNAs (miRNAs) has been desired, in particular, when they are differently expressed in normal and pathological conditions. However, various methods for the quantification of small non-coding RNAs as well as miRNAs have been described. These methods mainly include hybridization-based approaches such as primer extension, northern blotting, microarray profiling, and reverse transcription (RT) PCR. Here, we developed a simple and rapid method based on stem-loop primer-based real-time PCR assay for sensitive and accurate detection of mature miRNAs. Initially, a miRNA-specific stem-loop RT primer is used for RT, which is followed by TaqMan real-time PCR assay using specific forward primer in combination with universal reverse primer and TaqMan probe. The assay has shown high sensitivity (≤50 copies/reaction) for miRNA detection in two breast cancer cell lines, MCF-7 and MDA-MB-231. This assay might be implicated as a rapid and cost effective method for the detection of small non-coding RNAs
Mir-302 cluster exhibits tumor suppressor properties on human unrestricted somatic stem cells
No full textMany studies have reported that miR-302-367 cluster acts in different ways in various cell types. For instance, this cluster is shown to have a potential role in stemness regulation in embryonic stem cells (ESCs). On the other hand, this cluster inhibits the tumorigenicity of human pluripotent stem cells by coordinated suppression of CDK2 and CDK4/6 cell cycle pathways. Indeed, this cluster has a significant posttranscriptional impact on cell cycle progression. Previous reports have shown the participation of miR-302-367 cluster in cell cycle regulation of hESCs, MCF7, HepG2, and Teta-2 embryonal teratocarcinoma cells, but its effect on unrestricted somatic stem cells (USSCs) as a new source of human somatic stem cells from the umbilical cord blood remains to be elucidated. Therefore, in this study, we aimed to investigate the effect of miR-302-367 cluster on cell proliferation by MTT assay, cell cycle analysis, and colony formation assay. In addition, the expression of candidate cell cycle regulatory performance and tumor suppressor genes was determined. In this study, for the first time, we found that miR-302-367 cluster not only did not reprogram human USSCs into a pluripotent ESC-like state, but also inhibited the proliferation of human USSCs. Moreover, analyzing the cell cycle curve revealed a significant apoptotic phase upon viral introduction of miR-302-367. Our gene expression study revealed the overexpression of candidate genes after transduction of USSCs with miR-302-367 cluster. In conclusion, the controversial role of miR-302-367 in different cell types may provide better understanding for its role in stemness level and its antitumorigenicity potential in different contexts
Production of recombinant Human T Lymphotropic Virus type 1 Tax protein in Rosetta (DE3) bacterial host
No full text HTLV1 is the first detected retrovirus causing disease in human. The physiopathology of HTLV1 related diseases was mainly linked with its Tax protein characteristics. Use of mutant Tax proteins accompanied by immune regulator drugs could help treating HTLV1 associated myelopathy patients as a modulator of potent immune response against this viral protein. Since Tax protein is not commercially available, production of recombinant Tax protein was targeted for this study. Coding sequence of Tax protein (containing R222K mutation) in the pcDNA3.1(+) was digested with BamHI and XhoI restriction enzymes, and then removed and inserted into the expression vector pET32a(+) within the same cutting sites and cloned into E.coli DH5α. Recombinant vector was confirmed with enzymatic digestion, colony PCR, and sequencing of cloned gene. E.coli Rosetta (DE3) was transformed with the recombinant plasmid and the expression was induced. The expression of protein was assayed with SDS-PAGE and western blot using monoclonal antibodies against Tax and 5His epitope. Finally, antigenic characteristic of the recombinant protein was evaluated by western blotting against patient sera. Presence of Tax protein band in the SDS-PAGE and western blot was confirmed. Western blotting of the recombinant protein with patient sera showed the band related to Tax protein. The recombinant protein is well produced and could be detected by patients' sera, making it eligible to be used as a recombinant viral antigen for future purposes
Fluid Structure Interaction (FSI) Based Wind Load Modelingfor Dynamic Analysis of Overhead Transmission Lines
No full textNote:Electricity is a crucial form of energy in our societies, and transmission lines are key elements to ensure the reliability of electric power grids. Continuity of service is the main preoccupation of electric utilities, and this continuity may be disrupted by a large variety of sources and accidents. Transmission lines, by their intrinsic topology, remain the grid components that are the most exposed to climatic sources of disruption. The most common and important source of dynamic loads on transmission lines results from wind effects on the towers and conductors. Conductors are particularly sensitive to wind effects as they are long and relatively flexible (compared to their supports) and are literally wind-catching structures in the power grid infrastructure. In cold climates, wind and ice have compounding effects on lines and give rise to the most severe design loading conditions. Therefore accurate prediction of the wind pressure on overhead conductors is essential to conduct a reliable assessment of the ine response, in terms of both electrical clearances and conductor loads transferred to supports. Spatial randomness of wind loads on overhead lines has already been addressed by stochastic analysis methods and is now taken into account in design with the use of so-called span factors. Further reasonable gains in wind load accuracy can be obtained by examining the physics of wind effects on conductors, in both non-iced and iced conditions, with improved predictions of lift and drag forces determined from fluid-structure interaction (FSI) analysis. The traditional design method to apply wind load on transmission lines is to convert the design wind speed to a static pressure through Bernoulli 's equation where the pressure is proportional to the air density and the squared wind speed. In this approach the fluid-structure interaction of wind and line components is ignored: wind is considered as a quasi-static load on conductors and supports, while special instability effects due to particular wind conditions suc as vortex shedding (Aeolian vibrations) and flutter (cable galloping) are accounted for separately with specific mitigation solutions if necessary. In gusty wind conditions with high turbulence intensity, conductors may experience large horizontal displacements that affect their surrounding wind flow. A physically accurate wind load evaluation on conductors is possible by computational wind-structure interaction analysis. To date, largely due to its high computational cost and the lack of experimental data to validate computational models, an advanced fluid-structure analysis framework for wind-cable interaction has not been developed. In this study a new approach based on FSI analysis to evaluate equivalent wind loads on conductors is developed. The first step in such an approach is accurate evaluation of wind pressure on conductor. For this purpose the FSI analysis is carried in two dimensions where the detailed bare and iced conductor section geometry and surrounding air flow are modeled, considering a gi en incident wind speed. The conductor cross section is assumed to be supported on flexible supports to study the interaction between the conductor motion and the air flow. FSI analysis yields both the fluid and structure response. Of particular interest is the wind pressure field on the conductor section, which allows the computation of the resultant drag and lift forces. This process is repeated for several cross sections along the span and the resulting forces provide the effective span wise wind load distribution on the conductor. This wind loading is then used as input in a separate 3-D computational nonlinear dynamic analysis model to predict the line response. This dynamic analysis of the line section can be detailed to represent very realistic line sections including conductors, suspension links and supporting towers. It should be emphasized that the author does not advocate the "complexification" of overhead line wind analysis with the introduction of FSI and dynamic computational simulations in engineering offices. It is rather proposed to use these advanced computational methods, in a research and development context, to evaluate and possibly improve current wind analysis methods. Another very interesting application of this computational technique relates to optimized cross-sectional design of conductors, in terms of geometry and surface roughness. Detailed FSI analysis also enables the evaluation of aerodynamic damping of various cable geometries. As many Canadian utilities are reassessing the reliability levels of their transmission infrastructure and making difficult investment decisions, a more realistic wind loading model could be of high value. Key words: Overhead transmission line wind loading; fluid-structure interactions; computational fluid dynamics; conductor lift and drag coefficients; interactive wind and ice effects; overhead line conductorsNos societes sont fortement dependantes de l'electricite, et il ne fait pas de doute que la fonctionnalite des !ignes de transport est determinante pour assurer la fiabilite des reseaux electriques modemes. En effet, la continuite de l'approvisionnement en electricite reste la preoccupation majeure de toutes les compagnies d'electricite, et cette continuite du service peut etre compromise par une multitude d'incidents ou d'accidents sur !'ensemble du reseau. Les !ignes de transport sont toutefois les composants du reseau qui sont les plus exposes aux charges climatiques ou environnementales susceptibles de declencher des pannes. Parmi toutes les sources possibles de charges dynamiques sollicitant les !ignes de transport, celles provenant des effets du vent sur les pylones et les conducteurs restent les plus frequentes. Les conducteurs de !ignes sont particulierement vulnerables aux effets du vent car les portees sont longues et flexibles (compare aux pylones) et leur presence physique dans le reseau en font ds structures exposees a toutes les intemperies qui peuvent survenir sur le territoire couvert. Cette vulnerabilite est encore plus grande dans les climats nordiques ou les effets combines du givrage atmospherique et du vent creent des scenarios de charges de conception parmi les plus critiques et done susceptibles de controler la conception finale des !ignes. Il nous apparait done essentiel de comprendre la dynamique des fluides des effets du vent pour predire avec realisme et un degre de precision raisonnable la pression du vent exercee sur les conducteurs. Une meilleure evaluation des charges dues au vent permettrait par le fait meme des predictions plus realistes de la reponse des lignes aux charges de vent, non seulement en terme de deplacements et degagements electriques mais aussi en terme des charges nettes transferees aux pylones par les conducteurs. La nature aleatoire des effets du vent sur les conducteurs a deja fait l'objet de nombreuses etudes scientifiques et les methodes d'analyse stochastique modemes permettent de cemer la question: les methodes de conception simplifiees qui sont suggerees dans les normes et guides tiennent compte de ces effets en utilisant un coefficient de portee global qui ajuste a la baisse les efforts calcules au pylone sous des charges supposees synchrones et uniformes le long des conducteurs. Cette recherche ne conceme pas cet aspect de la question. Nous croyons que des gains de precision appreciables dans la prediction des charges de vent sur les lignessont possibles par une meilleure modelisation de la physique des effets du vent sur les conducteurs, dans les conditions givrees ou non, en utilisant les techniques d'analyse qui tiennent compte des interactions dynamiques fluide-structure. Ces interactions sont ignorees dans les methodes d'analyse conventionnelles qui consistent simplement a calculer une pression statique proportionnelle a la vitesse carree du fluide selon l' equation classique de Bemouilli. Bien sur, les concepteurs ne negligent pas la consideration des vibrations eoliennes ou du galop des conducteurs, mais ces phenomenes sont traites separement et n'influencent pas le calcul des charges sur les pyl6nes. Dans cette recherche, nous nous interessons aux conditions de vent de rafale avec grande turbulence qui caracterisent les tempetes de vent. Ces vents forts et turbulents creent de grands deplacements des conducteurs qui modifient les conditionsd'ecoulement d' air. Une evaluation plus precise de ces conditions est possible par analyse computationnelle des interactions vent-conducteur. Les bases theoriques de la physique des phenomenes en presence sont connues mais aucun cadre d'application numerique n'a ete propose a date, en partie a cause des couts numeriques eleves mais aussi du au manque de donnees experimentales pouvant valider ces modeles computationnels. Nous avons developpe un tel cadre d' analyse computationnelle dans cette recherche et 1' avons illustre dans un cycle complet, du calcul des charges au calcul de la reponse d'une section de ligne, avec plusieurs exemples pratiques a chacune des etapes de developpement. L'etape initiate consiste a determiner precisement le champ des pressions exercees a la surface d 'un conducteur de ligne a partir de modeles en deux dimensions qui rendent la reponse detaillee d 'une section de conducteur sur supports flexibles dans un ecoulement d'air a vitesse de vent incidente donnee. Une analyse CFD (dynamique des fluides computationnelle) du domaine fluide, l'air en mouvement entourant le conducteur, procede interactivement avec une analyse des deplacements de la section de conducteur, pour determiner les forces nettes (trainee et portance) agissant a !'interface airconducteur. Le processus est repete a volonte pour differentes conditions de support duconducteur ( correspondant a diverses positions le long de la portee) et pour une serie temporelle de conditions de vitesse de vent incident. Au final, on peut ainsi calculer un historique des forces dues au vent sur une portion tributaire de la portee jugee representative et utiliser ces forces comme des charges extemes sur des modeles d'analyse dynamique non lineaire de sections de lignes en trois dimensions. Ces analyses peuvent etre detaillees a souhait pour determiner la reponse dynamique des conducteurs, accessoires d'attache et pylones sous vents turbulents. Nous insistons sur le fait que nous ne suggerons pas une complexification de !'analyse des !ignes de transport sous les effets du vent dans les bureaux d'etudes a !'aide de modeles dynamiques sophistiques combinant les interactions des domaines fluides et solides. Nous proposons plutot d' utiliser le cadre computationnel mis a l'epreuve danscette recherche dans un contexte de recherche et developpement pour evaluer et possiblement ameliorer les methodes statiques conventionnelles. Une autre application interessante conceme la conception optimisee de la geometrie des conducteurs de lignes en termes de proprietes aerodynamiques. Mots cles: vent sur les !ignes aeriennes de transmission; interactions fluide-structure ; dynamique des fluides computationnelle ; coefficients de trainee et de portance des conducteurs ; interactions vent et givre
Mesenchymal stem cells as vehicles for targeted delivery of anti-angiogenic protein to solid tumors
No full textCritical Analysis of Grammatical Metaphor of Nominalization in English and Persian Political Discourses
No full textNominalization is one of the metaphors introduced by Halliday, which is a part of ideational meta-function. The present research study is an attempt to investigate the role of nominalization in political Persian and English discourses from Van Dijk’s Critical Discourse Analysis (CDA) perspective. In so doing, it attempts to answer the following research questions: (1) Does nominalizations have any role in cohesion and coherence as well as in marginalization and highlighting in the text? (2) What’s ideological role of nominalization in Persian and English political discourse? (3) In which discourse (Persian or English) more nominalizations are used? By studying 22/5 pages of English newspapers (Guardian, USA Today, Telegraph and New York Times) and 22/5 pages of Persian newspapers (Keyhan, Qods and Shargh) focused principally on Iran’s nuclear program negotiations, it was discovered that nominalization can cause marginalization and highlighting by changing information construction of the sentence (theme and rheme), referring to presuppositions, using entailment, omitting the agent and changing the mental models. Nominalization helps the author to make reference to the background knowledge of the reader without giving any repetitive information (coherence). It also helps the writer to use nouns (next to each other) which have the same conceptual meaning (cohesion). Furthermore, it can be concluded that this metaphor is used more frequently in Persian newspapers than in English ones
A phenomenological study of the process of ICT-competence of Iranian teachers with the purpose of presenting a native model
No full textBackground and Objectives: Research findings about the application of information and communication technologies in classroom has shown that despite the efforts had been done and the large amount of costs spent for empowering teachers' computer skills, but these activities have not been able to create desired changes in the role and activity of teachers in schools. Therefore, the purpose of the present study was to study the phenomenological process of Iranian teachers' ICT competence in order to present a native model. Methods: This was a qualitative phenomenological research, because the lived experiences of teachers in achieving technological competence in the classroom have been used to explore the objectives of the study. The statistical population of this qualitative study were all teachers in Urmia city. 22 teachers (13 females and 9 males) were selected by non-probability purposeful sampling method with considering the desired characteristics and theoretical saturation based-rule. Participants who engaged in 17 different schools including public, board of trustees, smart, nonprofit, and rural schools, were selected. The data collection tool was semi-structured interview. Voice recording and note-taking (with emphasis on voice recording), as Two techniques for gathering data, were used. George's (1970) four-step coding approach were used to analyze the data. The coding process was performed in MAXQDA10 software. Findings:The findings of the qualitative analysis indicated that the process of teachers ICT-competence can be organized into five components, including; 1) motivation/ tendency/ interest in teachers including the following sub-components: “Changing in teacher’s salary”, “Changing teachers’ position”, “Create need”, “Classification of teachers based on the prior knowledge”, “Pay attention to the timing of the courses” , “Changing the look to the teaching profession” and “Choosing the right professor”; 2) planning, including the following sub-components: “Teachers Rating (Needs Assessment)” , “Determining curriculum (educational topics)”, “Choosing the right professor”, “Locate the right place” and “Determine the right time”; 3) beginning of the learning process including the following components: “Hardware training”, “Software training”, “Problem-solving training”, “Information literacy training”, “Facilitate access to educational resources” and “Support”; 4) implementation of the learning process including the following sub-components: “In-service preparation courses”, “In-service training courses”, “Specialized school courses”, and “Out-of-school courses” and 5) " institutionalization of technology competence " including the following sub-components: “Problem-solving training’, “Formalize collaboration between teachers” and ‘Formalize follow-up courses for teaching and learning”. Conclusion: This model is presented by looking at the needs of teachers, the conditions and Organizational structure of education, the facilities of schools, the status of courses, the cooperation between teachers, and so on. In this model, all the influential factors in the process of acquiring information and technology competence by teachers have been included and based on the content of the interviews, each of them has been considered in the relevant step. Although it could be organized these components or steps in hierarchical or step-by-step structure, but in many places it is possible to go back and start from the previous step. It is hoped that this model will be a step towards developing an appropriate model in the field of staff technology competence for the Education Organization and other organizations.
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Ethanolic extract of <i>Ferula gummosa</i> is cytotoxic against cancer cells by inducing apoptosis and cell cycle arrest
No full text<div><p><i>Ferula gummosa</i> Boiss. has medicinal applications in treating a wide range of diseases including cancer. The objective of this study was to evaluate the antiproliferative activities of the seed and gum extracts of <i>F. gummosa</i> as well as to study the effect of the potent extract on the induction of apoptosis and cell cycle arrest. Our results demonstrated that the ethanolic extract had the lowest IC<sub>50</sub> value at 72 h (0.001 ± 1.2 mg/mL) in BHY cells. Moreover, flowcytometry and annexin-V analysis revealed that the ethanolic extract induced apoptosis and cell-cycle arrest in BHY cells at G1/S phase. In addition, colorimetric methods exhibited the highest amount of total phenolics and flavonoids in the aqueous and gum extracts (0.12 ± 0.037, 0.01 ± 2.51 mg/g of dry powder). Generally, the results obtained indicate that <i>F. gummosa</i> ethanol extract may contain effective compounds which can be used as a chemotherapeutic agent.</p></div
Generation and characterization of a functional Nanobody against the vascular endothelial growth factor receptor-2; angiogenesis cell receptor
No full textInternational audienceVascular endothelial growth factor receptor-2 (VEGFR2) is an important tumor-associated receptor and blockade of the VEGF receptor signaling can lead to the inhibition of neovascularization and tumor metastasis. Nanobodies are the smallest intact antigen binding fragments derived from heavy chain-only antibodies occurring in camelids. Here, we describe the identification of a VEGFR2-specific Nanobody, named 3VGR19, from dromedaries immunized with a cell line expressing high levels of VEGFR2. We demonstrate by FACS, that 3VGR19 Nanobody specifically binds VEGFR2 on the surface of 293KDR and HUVECs cells. Furthermore, the 3VGR19 Nanobody potently inhibits formation of capillary-like structures. These data show the potential of Nanobodies for the blockade of VEGFR2 signaling and provide a basis for the development of novel cancer therapeutics
Does microgravity effect on oral and maxillofacial region?
No full textSince the beginning of the era of space travel, there have been mentions of related health effects. Various studies have described the effect of space travel and microgravity on health. Some of these studies involved short and extended follow-ups of the effect of microgravity on the head and neck of astronauts. Therefore, we aimed to analyse the oral and maxillofacial health effects associated with this sophisticated mission. It is essential to identify relevant problems and address microgravity complications. Humans have long dreamed of flying and in recent years, the dream has evolved to exploring space and creating new habitats on other planets such as Mars. This led to an increase in the need for dental treatment of the flight crew members, which led to the creation of aviation dentistry for the screening and treatment of the oral cavity of the flight crew. We are moving towards a more conservative approach than before, such as removing pulpless teeth in aircrew patients or extracting roots that had a fracture or incomplete extraction. With all the advancements in aerospace knowledge, the aviation dentistry has rarely or briefly been discussed in dental textbooks. Dentists must screen each flight crew member thoroughly and impose flight restrictions and ground them if necessary; the reasons will be discussed later within this paper. It is the duty of dentists and surgeons to notify their patients (aircrew members) about the postoperative flight consequences and restrictions. © 2020 The Author(s),. Published by Cambridge University Press
