1,550 research outputs found

    The ‘subaltern’ foreign policies of North African countries: old and new responses to economic dependence, regional insecurity and domestic political change

    Get PDF
    This is the author accepted manuscript. The final version is available from Taylor & Francis (Routledge)via the DOI in this record.This article introduces the special issue by explaining why researching change and continuity in the foreign policies of North African states is relevant in spite of these countries’ peripheral and ‘subaltern’ position within the global system. It situates the special issue’s content in the context of the extant academic literature on the foreign policies of dependent/Third World/Global South countries, the foreign policies of MENA states and the consequences of the 2011 Arab uprisings in terms of international relations. It then moves on to discuss the case study selection by outlining key commonalities and differences between Mauritania, Morocco, Algeria, Tunisia, Libya and Egypt in terms of historical, political and economic foreign policy determinants. The country case studies each focus on a particular level of analysis, from the global – Tunisia’s financial predicaments and foreign debt negotiations – through the (sub)regional – Egypt’s relationship of necessity with Saudi Arabia, Algeria’s half-hearted policies towards the conflicts in Libya and Mali – to the domestic sphere – Morocco’s power balance between the monarchy and the Islamist Justice and Development Party (PJD) heading the government, Libya’s extreme state weakness and internal power competition among proliferating private actors –, reaching also the deeper non-state societal level – Mauritania’s new forms of social activism questioning the official religious identity and the socio-political makeup of the state. The last part of the introduction critically relates the empirical findings of the special issue to theoretical debates on subalternity in International Relations and Mohammed Ayoob’s subaltern realism in particular.The research leading to this article was funded by the grant ‘The International Dimension of Political Transformations in the Arab World’ (CSO2014-52998-C3-3-P), awarded by the Ministry of Economy and Competitiveness of Spain to the Universidad de Castilla-La Mancha

    Síntesis y evaluación citotoxica de derivados halogenados y peracetylados de nucleósidos en celulas de cancer de mama

    Get PDF
    Objectives. To make the synthesis of halogenated derivatives on the nitrogenous base and their respective acyl ester and amide type derivatives for all hydroxyl and amine groups of the uridine and cytarabine nucleosides, and evaluate cytotoxicity against breast cancer cell line. Methods. First, it was accomplished the halogenation reaction on the 5-position of the nitrogenous base, subsequently, the ester and amide derivatives were performed for all hydroxyl and amine group present in the nucleosides. Besides, the uridine acetonide derivatives as prepared by acid catalysis. The products were characterized by nuclear magnetic resonance spectroscopy (1H RMN y 13C RMN) and mass spectrometry in positive mode by direct injection. Derivatives were evaluated in Chinese hamster ovary (CHO-K1) and human breast cancer (MCF-7) cell lines. Results. The four derivatives were obtained with chlorine and bromine for the uridine and cytarabine, respectively, their respective per-acetylated derivatives, the per-acetylated nucleoside and the uridine acetonide; the compounds were obtained with efficiency over 90%. The per-acetylated nucleosides and the halogenated and per-acetylated derivatives did not show inhibitory effects on cell viability in MCF-7 cell line. However, the per-acetylated and halogenated derivatives presented a higher cytotoxic activity than their respective per-acetylated nucleoside. The uridine 3’,4’-acetonide showed a significant cytotoxicity on both cell lines. Conclusions. The per-acetylated nucleoside, and the respective halogenated derivatives with chlorine and bromine were obtained with high yields, nevertheless, these compounds did not exhibit a significant anti-proliferative activity (p˂0.05), possibly due to a low intra-cellular activation.Objetivos: Sintetizar derivados halogenados sobre la base nitrogenada, sus respectivos derivados tipo éster o amida de todos los grupos hidroxilo y amina presentes en los nucleósidos uridina y citarabina, y evaluar su actividad citotóxica sobre una línea celular de cáncer de mama. Metodología: primero se realizó la reacción de halogenación en la posición 5 de la base nitrogenada, posteriormente se formaron los ésteres y amidas de todos los grupos hidroxilos y amino presentes en los nucleósidos. Además, se preparó el derivado acetónido con catálisis ácida. Los compuestos se caracterizaron por espectroscopía de resonancia magnética nuclear (RMN 1H y RMN 13C) y espectrometría de masas por inyección directa en modo positivo. Los derivados se evaluaron sobre líneas celulares de tumor de Ovario de Hámster Chino (CHO) y de cáncer de mamá (MCF-7). Resultados: Se obtuvieron 4 derivados mono-halogenados con cloro y bromo de la uridina y citarabina, respectivamente, sus respectivos derivados per-acetilados, los nucleósidos per-acetilados y el acetónido de la uridina; los compuestos se obtuvieron con rendimientos superiores a 90%. Los nucleósidos per-acetilados, y los derivados per-acetilados y halogenados no exhibieron una inhibición significativa de la viabilidad celular en ambas líneas celulares, sin embargo, de estos, los derivados per-acetilados y halogenados presentaron mayor actividad citotóxica que los respectivos nucleósidos per-acetilados. El derivado acetónido de la uridina mostró citotoxicidad significativa sobre ambas líneas celulares. Conclusiones: se obtuvieron los nucleósidos per-acetilados y los respectivos derivados clorados y bromados de estos, con rendimientos altos, sin embargo, estos compuestos no exhibieron una actividad anti-proliferativa significativa (p˂0,05), posiblemente debido a una baja activación intra-celular de los nucleósidos

    Lubricity of paraffinic fuels additivated with conventional and non-conventional methyl esters

    Full text link
    [EN] Fuel lubricity prevents wear between metallic parts in relative motion inside the injection system of combustion engines. Among diesel fuels, paraffinic (gas-to-liquid or hydrotreated oils) and biodiesel (methyl esters) fuels are emerging since some of them are renewable and, in the case of paraffinic fuels, present excellent properties that can be exploited in compression ignition engines. However, the lubricant properties of raw paraffinic fuels are poor. This work explores the potential of individual methyl esters, found in different biodiesel fuels derived from a wide variety of sources, as lubricity additives for paraffinic fuels. Blends at 1% and 2% ester content in a surrogate of paraffinic fuel were tested under the standardized high-frequency reciprocating rig test for lubricity determination. Results confirm the extremely poor lubricity of the surrogate and that the wear scar diameter measured (the higher this, the lower the fuel lubricity) can be significantly reduced with any of the tested esters just at 1% concentration. Higher ester concentration (2%) does not always improve the lubricity further. The number of double bonds in the ester was revealed very significant, but to boost the lubricity of the blend and fulfill the limits set in fuel quality standards, two or more polyunsaturated esters are necessary.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study has been carried out under the framework of project ENE2016-79641-R, financed by the Spanish Ministry of Economy, Industry and Competitiveness.Rodriguez-Fernandez, J.; Ramos, A.; Sanchez-Valdepeñas, J.; Serrano, J. (2019). Lubricity of paraffinic fuels additivated with conventional and non-conventional methyl esters. Advances in Mechanical Engineering. 11(9):1-8. https://doi.org/10.1177/1687814019877077S18119Hsieh, P. Y., & Bruno, T. J. (2015). A perspective on the origin of lubricity in petroleum distillate motor fuels. Fuel Processing Technology, 129, 52-60. doi:10.1016/j.fuproc.2014.08.012Anastopoulos, G., Kalligeros, S., Schinas, P., & Zannikos, F. (2013). Effect of dicarboxylic acid esters on the lubricity of aviation kerosene for use in CI engines. Friction, 1(3), 271-278. doi:10.1007/s40544-013-0025-zAnastopoulos, G., Kaligeros, S., Schinas, P., Zannikou, Y., Karonis, D., & Zannikos, F. (2017). The Impact of Fatty Acid Diisopropanolamides on Marine Gas Oil Lubricity. Lubricants, 5(3), 28. doi:10.3390/lubricants5030028Sajjad, H., Masjuki, H. H., Varman, M., Kalam, M. A., Arbab, M. I., Imtenan, S., & Rahman, S. M. A. (2014). Engine combustion, performance and emission characteristics of gas to liquid (GTL) fuels and its blends with diesel and bio-diesel. Renewable and Sustainable Energy Reviews, 30, 961-986. doi:10.1016/j.rser.2013.11.039Lapuerta, M., Sánchez-Valdepeñas, J., & Sukjit, E. (2014). Effect of ambient humidity and hygroscopy on the lubricity of diesel fuels. Wear, 309(1-2), 200-207. doi:10.1016/j.wear.2013.11.017Sundus, F., Fazal, M. A., & Masjuki, H. H. (2017). Tribology with biodiesel: A study on enhancing biodiesel stability and its fuel properties. Renewable and Sustainable Energy Reviews, 70, 399-412. doi:10.1016/j.rser.2016.11.217Chong, W. W. F., & Ng, J.-H. (2016). An atomic-scale approach for biodiesel boundary lubricity characterisation. International Biodeterioration & Biodegradation, 113, 34-43. doi:10.1016/j.ibiod.2016.03.029De Oliveira, J. J., de Farias, A. C. M., & Alves, S. M. (2017). Evaluation of the biodiesel fuels lubricity using vibration signals and multiresolution analysis. Tribology International, 109, 104-113. doi:10.1016/j.triboint.2016.12.031Anastopoulos, G., Lois, E., Serdari, A., Zanikos, F., Stournas, S., & Kalligeros, S. (2001). Lubrication Properties of Low-Sulfur Diesel Fuels in the Presence of Specific Types of Fatty Acid Derivatives. Energy & Fuels, 15(1), 106-112. doi:10.1021/ef990232nGeller, D. P., & Goodrum, J. W. (2004). Effects of specific fatty acid methyl esters on diesel fuel lubricity. Fuel, 83(17-18), 2351-2356. doi:10.1016/j.fuel.2004.06.004Greenspan, L. (1977). Humidity fixed points of binary saturated aqueous solutions. Journal of Research of the National Bureau of Standards Section A: Physics and Chemistry, 81A(1), 89. doi:10.6028/jres.081a.011Tavakoli, O., & Yoshida, H. (2006). Squid Oil and Fat Production from Squid Wastes Using Subcritical Water Hydrolysis:  Free Fatty Acids and Transesterification. Industrial & Engineering Chemistry Research, 45(16), 5675-5680. doi:10.1021/ie0513806Kacem, M., Sellami, M., Kammoun, W., Frikha, F., Miled, N., & Ben Rebah, F. (2011). Seasonal Variations in Proximate and Fatty Acid Composition of Viscera ofSardinella aurita, Sarpa salpa, andSepia officinalisfrom Tunisia. Journal of Aquatic Food Product Technology, 20(2), 233-246. doi:10.1080/10498850.2011.560365Üstün, G., Akova, A., & Dandik, L. (1996). Oil content and fatty acid composition of commercially important Turkish fish species. Journal of the American Oil Chemists’ Society, 73(3), 389-391. doi:10.1007/bf02523436Noriega-Rodríguez, J. A., Ortega-García, J., Angulo-Guerrero, O., García, H. S., Medina-Juárez, L. A., & Gámez-Meza, N. (2009). Oil production from sardine (Sardinops sagax caerulea) Producción de aceite a partir de sardina (Sardinops sagax caerulea. CyTA - Journal of Food, 7(3), 173-179. doi:10.1080/19476330903010243Suseno, S., Hayati, S., & Izaki, A. (2014). Fatty Acid Composition of Some Potential Fish Oil from Production Centers in Indonesia. Oriental Journal of Chemistry, 30(3), 975-980. doi:10.13005/ojc/300308Volkman, J. K., Jeffrey, S. W., Nichols, P. D., Rogers, G. I., & Garland, C. D. (1989). Fatty acid and lipid composition of 10 species of microalgae used in mariculture. Journal of Experimental Marine Biology and Ecology, 128(3), 219-240. doi:10.1016/0022-0981(89)90029-4Stansell, G. R., Gray, V. M., & Sym, S. D. (2011). Microalgal fatty acid composition: implications for biodiesel quality. Journal of Applied Phycology, 24(4), 791-801. doi:10.1007/s10811-011-9696-xLang, I., Hodac, L., Friedl, T., & Feussner, I. (2011). Fatty acid profiles and their distribution patterns in microalgae: a comprehensive analysis of more than 2000 strains from the SAG culture collection. BMC Plant Biology, 11(1), 124. doi:10.1186/1471-2229-11-124Furlan, V. J. M., Maus, V., Batista, I., & Bandarra, N. M. (2017). Production of docosahexaenoic acid by Aurantiochytrium sp. ATCC PRA-276. Brazilian Journal of Microbiology, 48(2), 359-365. doi:10.1016/j.bjm.2017.01.001Zi-zhe, C., De-po Yang, Sheng-qing, W., Yong, W., Reaney, M. J. T., Zhi-min, Z., … Wen-zhe, Y. (2017). Conversion of poultry manure to biodiesel, a practical method of producing fatty acid methyl esters via housefly (Musca domestica L.) larval lipid. Fuel, 210, 463-471. doi:10.1016/j.fuel.2017.08.109Hussein, M., Pillai, V. V., Goddard, J. M., Park, H. G., Kothapalli, K. S., Ross, D. A., … Selvaraj, V. (2017). Sustainable production of housefly (Musca domestica) larvae as a protein-rich feed ingredient by utilizing cattle manure. PLOS ONE, 12(2), e0171708. doi:10.1371/journal.pone.0171708Dodos, G. S., Karonis, D., Zannikos, F., & Lois, E. (2015). Renewable fuels and lubricants from Lunaria annua L. Industrial Crops and Products, 75, 43-50. doi:10.1016/j.indcrop.2015.05.046Miwa, T. K. (1971). Jojoba oil wax esters and derived fatty acids and alcohols: Gas chromatographic analyses. Journal of the American Oil Chemists Society, 48(6), 259-264. doi:10.1007/bf02638458Kleiman, R., & Spencer, G. F. (1982). Search for new industrial oils: XVI. Umbelliflorae-seed oils rich in petroselinic acid. Journal of the American Oil Chemists’ Society, 59(1), 29-38. doi:10.1007/bf02670064Gill, S. S., Tsolakis, A., Dearn, K. D., & Rodríguez-Fernández, J. (2011). Combustion characteristics and emissions of Fischer–Tropsch diesel fuels in IC engines. Progress in Energy and Combustion Science, 37(4), 503-523. doi:10.1016/j.pecs.2010.09.001Rodríguez-Fernández, J., Lapuerta, M., & Sánchez-Valdepeñas, J. (2017). Regeneration of diesel particulate filters: Effect of renewable fuels. Renewable Energy, 104, 30-39. doi:10.1016/j.renene.2016.11.059Musavi, A., Cizmeci, M., Tekin, A., & Kayahan, M. (2008). Effects of hydrogenation parameters ontrans isomer formation, selectivity and melting properties of fat. European Journal of Lipid Science and Technology, 110(3), 254-260. doi:10.1002/ejlt.200700118Sukjit, E., Herreros, J. M., Dearn, K. D., García-Contreras, R., & Tsolakis, A. (2012). The effect of the addition of individual methyl esters on the combustion and emissions of ethanol and butanol -diesel blends. Energy, 42(1), 364-374. doi:10.1016/j.energy.2012.03.041Knothe, G., & Steidley, K. R. (2005). Lubricity of Components of Biodiesel and Petrodiesel. The Origin of Biodiesel Lubricity†. Energy & Fuels, 19(3), 1192-1200. doi:10.1021/ef049684cLapuerta, M., Sánchez-Valdepeñas, J., Bolonio, D., & Sukjit, E. (2016). Effect of fatty acid composition of methyl and ethyl esters on the lubricity at different humidities. Fuel, 184, 202-210. doi:10.1016/j.fuel.2016.07.019Pittman, J. K., Dean, A. P., & Osundeko, O. (2011). The potential of sustainable algal biofuel production using wastewater resources. Bioresource Technology, 102(1), 17-25. doi:10.1016/j.biortech.2010.06.035Chamorro R. Lubricity of a paraffinic surrogated fuel blended with non-conventional methyl esters. Final Degree Project in Mechanical Engineering, University of Castilla-La Mancha, Ciudad Real, 2018 (in Spanish)

    Fixed Effect Estimation of Large T Panel Data Models

    Get PDF
    This article reviews recent advances in fixed effect estimation of panel data models for long panels, where the number of time periods is relatively large. We focus on semiparametric models with unobserved individual and time effects, where the distribution of the outcome variable conditional on covariates and unobserved effects is specified parametrically, while the distribution of the unobserved effects is left unrestricted. Compared to existing reviews on long panels (Arellano and Hahn 2007; a section in Arellano and Bonhomme 2011) we discuss models with both individual and time effects, split-panel Jackknife bias corrections, unbalanced panels, distribution and quantile effects, and other extensions. Understanding and correcting the incidental parameter bias caused by the estimation of many fixed effects is our main focus, and the unifying theme is that the order of this bias is given by the simple formula p/n for all models discussed, with p the number of estimated parameters and n the total sample size.Comment: 40 pages, 1 tabl

    Estimating the frequency of Asian cytochrome B haplotypes in standard European and local Spanish pig breeds

    Get PDF
    Mitochondrial DNA has been widely used to perform phylogenetic studies in different animal species. In pigs, genetic variability at the cytochrome B gene and the D-loop region has been used as a tool to dissect the genetic relationships between different breeds and populations. In this work, we analysed four SNP at the cytochrome B gene to infer the Asian (A1 and A2 haplotypes) or European (E1 and E2 haplotypes) origins of several European standard and local pig breeds. We found a mixture of Asian and European haplotypes in the Canarian Black pig (E1, A1 and A2), German Piétrain (E1, A1 and A2), Belgian Piétrain (E1, A1), Large White (E1 and A1) and Landrace (E1 and A1) breeds. In contrast, the Iberian (Guadyerbas, Ervideira, Caldeira, Campanario, Puebla and Torbiscal strains) and the Majorcan Black pig breeds only displayed the E1 haplotype. Our results show that the introgression of Chinese pig breeds affected most of the major European standard breeds, which harbour Asian haplotypes at diverse frequencies (15–56%). In contrast, isolated local Spanish breeds, such as the Iberian and Majorcan Black pig, only display European cytochrome B haplotypes, a feature that evidences that they were not crossed with other Chinese or European commercial populations. These findings illustrate how geographical confinement spared several local Spanish breeds from the extensive introgression event that took place during the 18th and 19th centuries in Europe

    Assisting dependent people at home through autonomous unmanned aerial vehicles

    Get PDF
    This work describes a proposal of autonomous unmanned aerial vehicles (AUAVs) for home assistance of dependent people. AUAVs will monitor and recognize human activities during flight to improve their quality of life. However, before bringing such AUAV assistance to real homes, several challenges must be faced to make them viable and practical. Some challenges are technical and some others are related to human factors. In particular, several technical aspects are described for AUAV assistance: (1) flight control, based on our active disturbance rejection control algorithm, (2) flight planning (navigation in obstacle environments), and, (3) processing signals, acquired both from flight-control and monitoring sensors. From the assisted person’s viewpoint, our research focuses on three cues: (1) the user’s perception about AUAV assistance, (2) the influence on human acceptance of AUAV appearance and behavior at home, and (3) the human-robot interaction between assistant AUAV and assisted person. Finally, virtual reality environments are proposed to carry out preliminary tests and user acceptance evaluations.This work has been partially supported by Spanish Ministerio de Ciencia, Innovación y Universidades, Agencia Estatal de Investigaci´on (AEI) / European Regional Development Fund (FEDER, UE) under DPI2016-80894-R grant, and by CIBERSAM of the Instituto de Salud Carlos III. Lidia M. Belmonte holds FPU014/05283 scholarship from Spanish Ministerio de Educaci´on y Formación Profesional

    An Improved High Order Finite Difference Method for Non-conforming Grid Interfaces for the Wave Equation

    Get PDF
    This paper presents an extension of a recently developed high order finite difference method for the wave equation on a grid with non-conforming interfaces. The stability proof of the existing methods relies on the interpolation operators being norm-contracting, which is satisfied by the second and fourth order operators, but not by the sixth order operator. We construct new penalty terms to impose interface conditions such that the stability proof does not require the norm-contracting condition. As a consequence, the sixth order accurate scheme is also provably stable. Numerical experiments demonstrate the improved stability and accuracy property

    Klebsiella pneumoniae is able to trigger epithelial-mesenchymal transition process in cultured airway epithelial cells

    Get PDF
    The ability of some bacterial pathogens to activate Epithelial-Mesenchymal Transition normally is a consequence of the persistence of a local chronic inflammatory response or depends on a direct interaction of the pathogens with the host epithelial cells. In this study we monitored the abilities of the K. pneumoniae to activate the expression of genes related to EMT-like processes and the occurrence of phenotypic changes in airway epithelial cells during the early steps of cell infection. We describe changes in the production of intracellular reactive oxygen species and increased HIF-1α mRNA expression in cells exposed to K. pneumoniae infection. We also describe the upregulation of a set of transcription factors implicated in the EMT processes, such as Twist, Snail and ZEB, indicating that the morphological changes of epithelial cells already appreciable after few hours from the K. pneumoniae infection are tightly regulated by the activation of transcriptional pathways, driving epithelial cells to EMT. These effects appear to be effectively counteracted by resveratrol, an antioxidant that is able to exert a sustained scavenging of the intracellular ROS. This is the first report indicating that strains of K. pneumoniae may promote EMT-like programs through direct interaction with epithelial cells without the involvement of inflammatory cells

    Evaluation of range of motion restriction within the hip joint

    Get PDF
    In Total Hip Arthroplasty, determining the impingement free range of motion requirement is a complex task. This is because in the native hip, motion is restricted by both impingement as well as soft tissue restraint. The aim of this study is to determine a range of motion benchmark which can identify motions which are at risk from impingement and those which are constrained due to soft tissue. Two experimental methodologies were used to determine motions which were limited by impingement and those motions which were limited by both impingement and soft tissue restraint. By comparing these two experimental results, motions which were limited by impingement were able to be separated from those motions which were limited by soft tissue restraint. The results show motions in extension as well as flexion combined with adduction are limited by soft tissue restraint. Motions in flexion, flexion combined with abduction and adduction are at risk from osseous impingement. Consequently, these motions represent where the maximum likely damage will occur in femoroacetabular impingement or at most risk of prosthetic impingement in Total Hip Arthroplasty
    corecore