144 research outputs found
Prediction of The High Voltage Insulators Service Life Based on The Effective Values of Leakage Currents
The insulation condition of overhead lines is one of the main factors affecting reliability of overhead power transmission lines. It is known that the process of insulation lapping or rupture is mainly affected by environmental conditions and the degree of pollution of the insulators surface. This paper substantiates the possibility of using the leakage current values of insulators for monitoring the state of insulation and predicting its resource. The results of experimental studies of leakage currents of high-voltage insulators depending on their service life are given, on the basis of which forecasting the possible resource of insulators is carried out. The results obtained can be used to develop more effective diagnostics for detecting insulator failures at an early stage to take appropriate measures to coordinate the insulation
IGF binding protein‐6 expression in vascular endothelial cells is induced by hypoxia and plays a negative role in tumor angiogenesis
Hypoxia stimulates tumor angiogenesis by inducing the expression of angiogenic molecules. The negative regulators of this process, however, are not well understood. Here, we report that hypoxia induced the expression of insulin‐like growth factor binding protein‐6 (IGFBP‐6), a tumor repressor, in human and rodent vascular endothelial cells (VECs) via a hypoxia‐inducible factor (HIF)‐mediated mechanism. Addition of human IGFBP‐6 to cultured human VECs inhibited angiogenesis in vitro . An IGFBP‐6 mutant with at least 10,000‐fold lower binding affinity for IGFs was an equally potent inhibitor of angiogenesis, suggesting that this action of IGFBP‐6 is IGF‐independent. The functional relationship between IGFBP‐6 and vascular endothelial growth factor (VEGF), a major hypoxia‐inducible angiogenic molecule, was examined. While VEGF alone increased angiogenesis in vitro , co‐incubation with IGFBP‐6 abolished VEGF‐stimulated angiogenesis. The in vivo role of IGFBP‐6 in angiogenesis was tested in flk1 :GFP zebrafish embryos, which exhibit green fluorescence protein in developing vascular endothelium, permitting visualization of developing blood vessels. Injection of human IGFBP‐6 mRNA reduced the number of embryonic inter‐segmental blood vessels by ∼40%. This anti‐angiogenic activity is conserved in zebrafish because expression of zebrafish IGFBP‐6b had similar effects. To determine the anti‐angiogenic effect of IGFBP‐6 in a tumor model, human Rh30 rhabdomyosarcoma cells stably transfected with IGFBP‐6 were inoculated into athymic BALB/c nude mice. Vessel density was 52% lower in IGFBP‐6‐transfected xenografts than in vector control xenografts. These results suggest that the expression of IGFBP‐6 in VECs is up‐regulated by hypoxia and IGFBP‐6 inhibits angiogenesis in vitro and in vivo .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90159/1/26201_ftp.pd
Realidad virtual en videojuegos como una herramienta para promover la actividad turística en Lima – Perú
El proyecto consiste en el desarrollo de un videojuego en Realidad Virtual en el cual se modela y muestra una referencia de un lugar turístico con un diseño 3D. Este software tiene como objetivo promover la actividad turística en Lima – Perú mediante la didáctica interacción con el escenario.
Durante el desarrollo del sistema se utilizó la metodología CASCADA (Análisis, Diseño, Implementación, Pruebas y Mantenimiento).
En el software, el usuario podrá recorrer un espacio (escenario), teniendo como objetivo completar los puntos para terminar el nivel satisfactoriamente.
Al finalizar el desarrollo, el software se le mostrará al público en la web y aplicativo móvil, el cual se le pondrá el instalador en el equipo del usuario que desea probarlo.Trabajo de investigaciónCampus Lima Centr
The transient receptor potential vanilloid 4 channel modulates uterine tone during pregnancy
The importance of gaining insight into the mechanisms underlying uterine quiescence and contractility is highlighted by the absence of an effective strategy to prevent or treat preterm labor, the greatest cause of perinatal mortality and morbidity worldwide. Although current evidence suggests that in myometrial smooth muscle cells (mSMCs) calcium homeostasis is modulated near term to promote uterine contractility, the efficacy of blocking voltage-operated calcium channels is limited by dose-related cardiovascular side effects. Thus, we considered whether uterine contractility might be modulated by calcium entry via transient receptor potential vanilloid 4 (TRPV4) channels. In mSMC, TRPV4 gene and protein expression increased with gestation, and TRPV4-mediated Ca2+ entry and contractility were increased in mSMC from pregnant compared to nonpregnant rats. Cell membrane TRPV4 expression was specifically increased, whereas the expression of β-arrestin-1 and β-arrestin-2, molecules that can sequester TRPV4 in the cytoplasm, decreased. Physical interaction of β-arrestin-2 and TRPV4 was apparent in nonpregnant, but absent in pregnant, mouse uterus. Moreover, direct pharmacologic activation of TRPV4 increased uterine contraction, but oxytocin-induced myometrial contraction was blocked by pharmacologic inhibition of TRPV4 and decreased in mice with global deletion of TRPV4. Finally, TRPV4 channel blockade prolonged pregnancy in two distinct in vivomurinemodels of preterm labor, whereas the absence of either β-arrestin-1 or β-arrestin-2 increased susceptibility to preterm labor. These data suggest that TRPV4 channel activity modulates uterine contractility and might represent a therapeutic target to address preterm labor
Purification and characterization of native human insulin-like growth factor binding protein-6
Insulin-like growth factor binding proteins (IGFBPs) are key regulators of insulin-like growth factor (IGF) mediated signal transduction and thereby can profoundly influence cellular phenotypes and cell fate. Whereas IGFBPs are extracellular proteins, intracellular activities were described for several IGFBP family members, such as IGFBP-3, which can be reinternalized by endocytosis and reaches the nucleus through routes that remain to be fully established. Within the family of IGFBPs, IGFBP-6 is unique for its specific binding to IGF-II. IGFBP-6 was described to possess additional IGF-independent activities, which have in part been attributed to its translocation to the nucleus; however, cellular uptake of IGFBP-6 was not described. To further explore IGFBP-6 functions, we developed a new method for the purification of native human IGFBP-6 from cell culture supernatants, involving a four-step affinity purification procedure, which yields highly enriched IGFBP-6. Whereas protein purified in this way retained the capacity to interact with IGF-II and modulate IGF-dependent signal transduction, our data suggest that, unlike IGFBP-3, human IGFBP-6 is not readily internalized by human tumor cells. To summarize, this work describes a novel and efficient method for the purification of native human insulin-like growth factor binding protein 6 (IGFBP-6) from human cell culture supernatants, applying a four-step chromatography procedure. Intactness of purified IGFBP-6 was confirmed by IGF ligand Western blot and ability to modulate IGF-dependent signal transduction. Cellular uptake studies were performed to further characterize the purified protein, showing no short-term uptake of IGFBP-6, in contrast to IGFBP-3
Efficacy of non-pharmacological interventions to treat malnutrition in older persons : A systematic review and meta-analysis. The SENATOR project ONTOP series and MaNuEL Knowledge Hub project
The preparation of this paper was supported by the MalNutrition in the ELderly (MaNuEL) knowledge hub. MaNuEL is supported by the Joint Programming Initiative ‘Healthy Diet for a Healthy Life’. The MaNuEL funding agencies supporting this paper are (in alphabetical order of participating Member State): France: Ecole Supérieure d’Agricultires (ESA); Germany: Federal Ministry of Food and Agriculture (BMEL) represented by Federal Office for Agriculture and Food (BLE); The Netherlands: The Netherlands Organisation for Health Research and Development (ZonMw). This work was also supported by the SENATOR trial (FP7-HEALTH-2012-305930).Peer reviewedPostprin
Conflicting Climate Change Frames in a Global Field of Media Discourse
Reducing global emissions will require a global cosmopolitan culture built from detailed attention to conflicting national climate change frames (interpretations) in media discourse. The authors analyze the global field of media climate change discourse using 17 diverse cases and 131 frames. They find four main conflicting dimensions of difference: validity of climate science, scale of ecological risk, scale of climate politics, and support for mitigation policy. These dimensions yield four clusters of cases producing a fractured global field. Positive values on the dimensions show modest association with emissions reductions. Data-mining media research is needed to determine trends in this global field.Peer reviewe
Leadership and the Art of Struggle: How Great Leaders Grow Through Challenge and Advertsity
Snyder not only describes the art of struggle, but also shows how it works a positive change in the life of real characters. From a psychological standpoint, this has a powerful humanizing impact on the reader. It reinforces the indisputable truth that, no matter how famous, a leader is still a human. as George states in his foreword, “only in acknowledging our own flaws and vulnerabilities can we become authentic leaders who empower people to perform to the best of their abilities” (p. x)
Creation of Closed Ecological Life Support Systems: Results, Critical Problems and Potentials
As experiments have shown, a closed ecological life support system based on a biological material exchange is fully realizable and contains possibilities for further improvement. This kind of closed human ecosystem can become a model not only of an earthly noosphere, but also of daughter noospheres that can be used to help humanity render space inhabitable without threatening other bodies of the solar system through the intrusion of earthly substances and biological autocatalytic processes. As such, it will allow humans to exist in space or on other solar bodies, while requiring only the input of energy and not allowing the release of metabolites into the surroundings. Partially closed technologies for regenerating the atmosphere, water, and vegetable nutrients can radically enhance the quality of life in extreme regions—in the Arctic, Antarctica, in deserts, and in high mountain settlements. Another aspect of closed life support technologies is that they enable the minimizing of the environmental pollution that results from human waste products and those of their domestic animals. That these technologies can find applications on Earth before human settlements appear on Mars or the Moon. The transition to essentially closed nonpolluting, non-deadlock life support technologies will be a noticeable step on the path toward the sustainable development of the noosphere
Signs of Colloquialization : Three Corpus-based Case Studies
Masteroppgaven undersøker tre pågående lingvistiske endringer i skriftlig engelsk i de to største variantene, britisk engelsk og amerikansk engelsk, både synkront og diakront. De tre endringene er: den økte bruken av sammentrukne former av (for det meste, men ikke utelukkende) verb i moderne skriftlig engelsk; mer utstrakt bruk av ordet like med forskjellige funksjoner som er typiske for en uformell stil, særlig like med sitat-funksjon, (dvs. når ordet brukes til å introdusere direkte tale); samt økt bruk av partikkelverb med partiklene up og out. For eksempel brukes en ikke-standard form som gonna 189 ganger mer i skriftlig amerikansk engelsk nå enn da den først ble attestert rundt 1910. Den uformelle bruken av like til å introdusere direkte tale er 68,5 ganger høyere i skriftlig amerikansk engelsk i 2013 enn på 1980-tallet, da denne bruken av like først opptrer. Bruken av partikkelverb med up har blitt tre ganger høyere i løpet av de siste 200 år i amerikansk engelsk. Dette er noen få eksempler på den typen fenomener denne masteroppgaven tar for seg.
Analysen tar utgangspunkt i det Mair (1997) kaller ‘the colloquialization of written English’, d.e. den økende innflytelsen som talespråket har på skriftspråket, og som kan ses i det stadig voksende antallet høyst uformelle lingvistiske trekk som har kommet fra dagligtalen inn i skriftspråket.
Analysen underbygges av en stor mengde data fra de største engelske tekstkorpuser som finnes for øyeblikket: the Corpus of Contemporary American English (COCA), the Corpus of Historical American English (COHA), the British National Corpus (BNC), the Google Books American English Corpus og the Google Books British English Corpus. Den synkrone delen av analysen sammenligner og gir en kvantitativ undersøkelse av korpusmateriale fra forskjellige tekstgenrer i COCA og BNC, mens den diakrone delen ser på utviklingen av de tre språkendringene over en periode på cirka 200 år, fra 1810 til dags dato, på grunnlag av materialet fra COHA og de to korpusene fra Google Books. Konklusjonene er entydige, og støtter i stor grad – om enn ikke fullt ut – Mairs hypotese
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