4,258 research outputs found

    Parameters influencing Ostwald ripening of Nanoemulsions produced by Premix Membrane Emulsification

    Get PDF
    Premix membrane emulsification is a promising method to produce colloidal lipid carrier systems, e.g. triglyceride nanoemulsions, with small particle sizes and narrow particle size distributions for intravenous administration. The stability of these systems can be affected by Ostwald ripening. The process of Ostwald ripening in emulsions of medium chain triglycerides stabilized with sucrose laurate was monitored by particle size measurements with photon correlation spectroscopy. Two different preparation methods were used and the concentration of free emulsifier measured to learn more about the influencing parameters. The concentration of free sucrose laurate turned out to be the main influencing parameter and should be about zero to minimize Ostwald ripening in the emulsions

    The call for experiential learning and educational outsourcing: business proposal for Nova Sbe and dialog social enterprise

    Get PDF
    In the past couple of years, universities and colleges have started introducing social entrepreneurship education and social enterprise initiatives within their curricula. Research has identified social entrepreneurship education as a different kind of education that is best delivered with experience and practice. Despite the theoretical nature of higher education, universities and colleges are capable of equipping and training students with the skills to start or join a social venture, however, with the transformation of their current approaches. While practice-based training in the form of case studies and writing business plans has proven beneficial, especially in the field of social entrepreneurship, this paper aims to bring into light the existing body of knowledge on the importance of experiential learning and educational outsourcing. Although done within the formal walls of universities and colleges, with the help of social entrepreneurs and social enterprises, the classroom can be altered to represent the real world provoking experience that can impact attitudes and intentions. Based on the review of the literature on social entrepreneurship and social ventures, this data is analyzed to set later the ground for a proposal of a potential partnership between Nova School of Business and Economics and Dialog Social Enterprise

    Reactivity and fate of secondary alkane sulfonates (SAS) in marine sediments

    Get PDF
    This research is focused on secondary alkane sulfonates (SAS), anionic surfactants widely used in household applications that access aquatic environments mainly via sewage discharges.We studied their sorption capacity and anaerobic degradation in marine sediments, providing the first data available on this topic. SAS partition coefficients increased towards those homologues having longer alkyl chains(from up to 141 L kg 1 for C14 to up to 1753 L kg 1 for C17), which were those less susceptible to undergo biodegradation. Overall, SAS removal percentages reached up to 98% after 166 days of incubation using anoxic sediments. The degradation pathway consisted on the formation of sulfocarboxylic acids after an initial fumarate attack of the alkyl chain and successive b-oxidations. This is the first study showing that SAS can be degraded in absence of oxygen, so this new information should be taken into account for future environmental risk assessments on these chemicals

    Symmetry in optics and photonics: a group theory approach

    Full text link
    Group theory (GT) provides a rigorous framework for studying symmetries in various disciplines in physics ranging from quantum field theories and the standard model to fluid mechanics and chaos theory. To date, the application of such a powerful tool in optical physics remains limited. Over the past few years however, several quantum-inspired symmetry principles (such as parity-time invariance and supersymmetry) have been introduced in optics and photonics for the first time. Despite the intense activities in these new research directions, only few works utilized the power of group theory. Motivated by this status quo, here we present a brief overview of the application of GT in optics, deliberately choosing examples that illustrate the power of this tool in both continuous and discrete setups. We hope that this review will stimulate further research that exploits the full potential of GT for investigating various symmetry paradigms in optics, eventually leading to new photonic devices.Comment: 20 page, 5 figure

    Determining the distribution of triclosan and methyl triclosan in estuarine settings

    Get PDF
    We have developed a method for the analysis of two sewage-derived contaminants: triclosan (TCS), an antibacterial agent, and methyl triclosan (MTCS), a TCS metabolite. For solid samples (4 g), extraction and cleanup were integrated into the same step using pressurized liquid extraction (PLE) with in-cell-clean-up (1 g of florisil). The extraction was performed using dichloromethane at 100 °C, 1500 psi and 3 static extraction cycles of 5 min each. For water samples (100 mL), stir bar sorptive extraction–liquid desorption (SBSE–LD) was used. Bars were stirred for 10 h and analytes were later desorbed using acetonitrile. Finally, MTCS and a silylated derivative of TCS were determined by gas chromatography–mass spectrometry (GC–MS). Recovery experiments in water and sediments were performed and the results ranged from 67% to 78%. Limits of detection (LODs) were 5 ng L−1 for TCS and 1 ng L−1 for MTCS, in water samples, and 0.1 ng g−1 for TCS and MTCS in solid samples. The method was applied then to determine the levels of these compounds in the estuary of Guadalete River (SW Spain). TCS and MTCS concentrations up to 9.6 ng g−1 in sediments and 310 ng L−1 in water were measured. Their distribution was strongly influenced by the presence of wastewater sources, treated and untreated, along the sampling area, where maximum concentrations were detected. Highest values were reached in the water column during low tides as the water volume in the estuary becomes lower

    Tourism, heritage territorial and development in the Northeastern Middle Atlas (Morocco)

    Get PDF
    Las montañas del nordeste del Medio Atlas marroquí constituyen una zona frágil y aislada, donde la población presenta precarias condiciones de vida. Desde el punto de vista natural y cultural, ocupan un lugar relevante en el conjunto de las montañas marroquíes al contar con recursos territoriales y patrimoniales. El turismo constituye una alternativa viable para activar el desarrollo económico y social. En este artículo se plantean las luces y las sombras que tendría la puesta en marcha de actividades propias del turismo, con un enfoque participativo y descentralizado.The mountains of northeastern Middle Atlas (Morocco) constitute a fragile and isolated area, where the population has precarious living conditions. From the point of natural and cultural, figure prominently in all the Moroccans to have territorial heritage resources and mountains. Tourism is a viable option to activate the economic and social development alternative. This article describes the lights and shadows that would start up of own tourism activities, with a participatory and decentralized approach arise.Unión Europea, Ministerio de Asuntos Exteriores, Agencia Española de Cooperación Internacional al desarrollo A/023361/1

    A new Strategy to Improve Drug Delivery to the Maxillary Sinuses: The Frequency Sweep Acoustic Airflow

    Get PDF
    International audiencePurpose Enhancement of intra-nasal sinus drug deposition involves nebulization of a drug superimposed by the acoustic airflow characterized by a specific frequency. We investigated the impact of fixed frequency versus frequency sweep acoustic airflow on the improvement of aerosolized drug penetration into the maxillary sinuses.Methods Fixed frequency and frequency sweep acoustic airflow were generated using a prototype of variable frequency nebulizing system, and their effect on the intra-nasal sinus aerosol deposition in a ‘nasal replica’, a transparent, water-resistant, non-porous resin replica of the human plastinated cast created using a stereolithography technique, was tested. Sodium fluoride and gentamicin were chosen as markers. In addition to this, the effect of sweep cycle and intensity variation was also studied. Results Studies performed using fixed frequency acoustic airflow showed that each of the maxillary sinuses of the ‘nasal replica’ required specific frequency for the optimal intra-nasal sinus aerosol deposition; depending on the ostia of the left and right maxillary sinuses which are different. Intra-nasal sinus drug deposition experiments under the effect of the frequency sweep acoustic airflow showed an optimal aerosol deposition into both maxillary sinus of the ‘nasal replica’. Studies on the effect of the duration of the sweep cycle showed that the shorter the cycle the better the deposition.Conclusion Our study demonstrates the benefit of frequency sweep acoustic airflow on the drug deposition into maxillary sinuses of the ‘nasal replica’ characterized by ostia of different geometry. However, the delivery rates of the ‘nasal replica’ cannot be directly applied to real human chronic rhinosinusitis condition; further in vivo studies have to be conducted

    Risk management in toll road concessions

    Get PDF
    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.Includes bibliographical references (leaves 82-84).With a degrading road infrastructure and dwindling public funds, governments are turning towards the private sector to develop roads and finance them though toll revenues. However, these high stakes endeavors were not always successful; in other words, they were not able to provide a fair return to the sponsors and investors while guaranteeing the public welfare and satisfying the government interests. A review of the international experience of toll roads, with a focus on developing countries, suggests that if a thorough and pertinent risk management program is implemented by private concessionaires, with the support of the government, then many risks could be mitigated, thus reducing the exposure of both the private sponsor and the government. Thus, in this study, we suggest a three-step risk management process. This first step of this process consists of identifying and classifying the risks in toll roads, according to the milieu from which they stem (project, market, country); the second step is an investigation in an array of risk mitigation strategies that are relevant to one or more risk categories; finally, the third step is risk analysis which consists of accounting for risks when evaluating a project. In the last two chapters, we will embody major issues in risk management in two case studies: In the first case study, New Batinah Highway project, we focus on the value of flexibility in toll roads and in the second case study, Melbourne City Link project, we focus mainly on the role of project organization and financial structure in risk management. Finally, in the conclusion, we emphasize that the private sponsor cannot be the only player in the risk management process but government support and commitment are vital. Thus we redefine the role of the government and the role of the private concessionaire in the provision of toll roads.by Lara A. El-Amm.S.M

    Measuring spontaneous mentalizing with a ball detection task : putting the attention-check hypothesis by Phillips and colleagues (2015) to the test

    Get PDF
    Theory of Mind (ToM) or mentalizing refers to the ability to attribute mental states (such as desires, beliefs or intentions) to oneself or others. ToM has been argued to operate in an explicit and an implicit or a spontaneous way. In their influential paper, Kovács et al. (Science 330:1830–1834, 2010) introduced an adapted false belief task—a ball detection task—for the measurement of spontaneous ToM. Since then, several studies have successfully used versions of this paradigm to investigate spontaneous ToM. This paradigm has, however, been criticized by Phillips et al. (Psychol Sci 26(9):1353–1367, 2015), who argue that the effects are fully explained by timing artifacts in the paradigm, namely differences in timing of the attention check. The main objective of the current study is to test this attention-check hypothesis. An additional aim was to relate the findings to autism spectrum disorder (ASD) symptomatology in our neurotypical sample, as ASD has been linked to deficits in spontaneous mentalizing. We applied an adjusted version of the paradigm in which the timings for all conditions are equalized, ruling out any potential timing confounds. We found significant main effects of own and agent beliefs on reaction times. Additionally, we found a significant ‘ToM-effect’: When participants believe the ball is absent, they detect the ball faster if the agent believes the ball would be present rather than absent, which refers to the original effect in the paper of Kovács et al. (2010), taken as evidence for spontaneous ToM and which was contested by Phillips et al. (2015). Our findings cannot be explained by the attention-check hypothesis. Effects could not be associated with ASD symptoms in our neurotypical sample, warranting further investigation on the link between spontaneous mentalizing and ASD
    • …
    corecore