520 research outputs found

    Tales from two cities: COVID-19 and the localisation of tourism in London and Paris

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    Purpose - Drawing on empirical research conducted in London and Paris between July 2020 and June 2021, this research explores whether these two global metropolises may be able to take the COVID-19 crisis as an opportunity to develop more sustainable forms of urban tourism. More specifically, the study analyses whether new forms of localised tourism have developed as a result of the pandemic, how these have been nurtured and encouraged by the tourism industry in these two cities, and the implications of these trends for the sustainable development of tourism in these two cities. Design/methodology/approach - A combination of research methods was used: an online Delphi method, followed by in-depth one to one interviews with selected stakeholders and complemented by the analysis of media articles, policy documents and secondary data. Findings - The qualitative data analysis highlights some key findings: tourism sustainability gained a new importance after the pandemic, however the crisis did not bring the sustainable revolution some stakeholders wished or expected. Nonetheless in both cities tourism marketing adopted a new "hyper-local" approach with the objective of encouraging proximity tourism and involving local residents more, thus pointing to the need to review traditional definitions of the (urban) tourist. Originality/value – While the blurring between tourism and the everyday in cities has been widely discussed in tourism theory, this research provides empirical evidence from two world tourism cities, showing some of the wider, practical implications of these theoretical debates for industry and policy making in the context of the COVID-19 pandemic

    Interaction patterns for smart spaces: a confident interaction design solution for pervasive sensitive IoT services

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    Smart spaces represent a powerful tool for deploying the new pervasive sensitive services based on Internet of Things products and developed in current Information Society close to users. Researchers have focused their efforts on new techniques to improve systems and products in this area but neglecting the human factors related to psychological aspects of the user and their psycho-social relationship with the deployment space where they live. This research proposes to take into account these cognitive features in early stages of the design of smart spaces by defining a set of interaction patterns. By using this set of interaction patterns it is possible to influence over the confidence that users can develop during the use of IoT products and services based on them. An evaluative verification has been carried out to assess how this design engineering approach provide a real impact on the generation of confidence in the users of this kind of technology

    Synthesis and characterization of a new norfloxacin/resorcinol cocrystal with enhanced solubility and dissolution profile

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    A new cocrystal of Norfloxacin, a poorly soluble fluoroquinolone antibiotic, has been synthetized by a solvent-mediated transformation experiment in toluene, using resorcinol as a coformer. The new cocrystal exists in both anhydrous and monohydrate forms with the same (1:1) Norfloxacin/resorcinol stoichiometry. The solubility of Norfloxacin and the hydrated cocrystal were determined by the shake-flask method. While Norfloxacin has a solubility of 0.32 ± 0.02 mg/mL, the cocrystal has a solubility of 2.64 ± 0.39 mg/mL, approximately 10-fold higher. The dissolution rate was tested at four biorelevant pH levels of the gastrointestinal tract: 2.0, 4.0, 5.5, and 7.4. In a first set of comparative tests, the dissolution rate of Norfloxacin and the cocrystal was determined separately at each pH value. Both solid forms showed the highest dissolution rate at pH 2.0, where Norfloxacin is totally protonated. Then, the dissolution rate decreases as pH increases. In a second set of experiments, the dissolution of the cocrystal was evaluated by a unique dissolution test, in which the pH dynamically changed from 2.0 to 7.4, stepping 30 min at each of the four biorelevant pH values. Results were quite different in this case, since dissolution at pH 2 affects the behavior of Norfloxacin at the rest of the pH values

    Solubility-pH profiles of a free base and its salt: sibutramine as a case study

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    In the present study the solubility-pH profiles of sibutramine free base and its hydrochloride salt were determined in the pH range between 2.0 and 9.5 by means of the recommended shake-flask method, and the solids collected were dried and studied by X-ray diffraction in order to elucidate their free base or salt structure. Above pHmax (or Gibbs pKa) the solid collected was always identified as free base, whatever the sibutramine species (free base or hydrochloride salt) initially solved. However, in the pH range below pHmax different solids were isolated depending on the buffers employed

    Potentiometric CheqSol and standardized shake-flask solubility methods are complimentary tools in physicochemical profiling

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    The solubility of three drugs (glimepiride, pioglitazone, sibutramine) with different acid/base properties and expected supersaturation behavior was examined in detail using the shake-flask (SF) and potentiometric (CheqSol) methods. Both uncharged (free) species and hydrochloride salts were used as starting materials. On the one hand, the SF method provided information about the thermodynamic solubility at any pH value, including the counterion-dependent solubility of ionic species. Additionally, this method easily allowed the identification of the solid phase in equilibrated solutions by powder X-ray diffraction, and the detection and quantification of aggregation and complexation reactions. On the other hand, CheqSol method permitted the measurement of the equilibrium solubility of neutral species, the observation of changes in solid forms, and the extent and duration of supersaturation (kinetic solubility) for 'chaser' compounds. The combined information from both methods gave an accurate picture of the solubility behavior of the studied drugs

    Polymorphism of Cocrystals: The Promiscuous Behavior of Agomelatine

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    It has been traditionally suggested that polymorphism of cocrystals is a phenomenon seen less frequently than in monocomponent crystals. However, since the research on cocrystals has recently experienced a big growth, the number of solved structures of polymorphic cocrystals in the Cambridge Structural Database has increased, which can help to understand better whether a lower impact of this phenomenon exists or not in multicomponent crystals. In this paper we describe the cocrystal landscape of agomelatine, a particularly promiscuous drug able to cocrystallize with up to nine different coformers. Interestingly, two of those coformers have produced polymorphic cocrystals during the screening, which converts agomelatine into a new example that questions the traditional belief of the lesser impact of polymorphism in cocrystals and highlights the importance of polymorphism studies in cocrystal screening. Our work is completed with the determination of the crystal structures of the new forms from combined single crystal/laboratory X-ray powder diffraction data

    Expanding the Crystal Form Landscape of the Antiviral Drug Adefovir Dipivoxil

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    The solid state of adefovir dipivoxil (AD) has been revisited. In the present article we extend the knowledge about the solid state of this pharmaceutical prodrug. The stability landscape of the amorphous form with respect to the anhydrous and hydrate crystalline forms has been studied, and the use of an antiplasticizing agent to increase its Tg is described. The crystal structure of the elusive anhydrous form I has been determined from laboratory powder X-ray diffraction data by means of direct space methods using the computing program FOX. In addition, three new isostructural solvates of AD (methanol, ethylenglycol, and methylethylketone) have been discovered and structurally characterized by single cristal X-ray diffraction

    Phage Display in the Quest for New Selective Recognition Elements for Biosensors

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    Phages are bacterial viruses that have gained a significant role in biotechnology owing to their widely studied biology and many advantageous characteristics. Perhaps the best-known application of phages is phage display that refers to the expression of foreign peptides or proteins outside the phage virion as a fusion with one of the phage coat proteins. In 2018, one half of the Nobel prize in chemistry was awarded jointly to George P. Smith and Sir Gregory P. Winter "for the phage display of peptides and antibodies." The outstanding technology has evolved and developed considerably since its first description in 1985, and today phage display is commonly used in a wide variety of disciplines, including drug discovery, enzyme optimization, biomolecular interaction studies, as well as biosensor development. A cornerstone of all biosensors, regardless of the sensor platform or transduction scheme used, is a sensitive and selective bioreceptor, or a recognition element, that can provide specific binding to the target analyte. Many environmentally or pharmacologically interesting target analytes might not have naturally appropriate binding partners for biosensor development, but phage display can facilitate the production of novel receptors beyond known biomolecular interactions, or against toxic or nonimmunogenic targets, making the technology a valuable tool in the quest of new recognition elements for biosensor development.This study was supported by the Ministry of Economy and Competitiveness (Ministerio de Ciencia, Innovación y Universidades RTI2018-096410-B-C21). R.P. acknowledges UCM for a predoctoral grant and R.B. the PI17CIII/00045 grant from the AES-ISCIII program.S

    Development and validation of a high performance liquid chromatography-tandem mass spectrometry method for the absolute analysis of 17 alpha D-amino acids in cooked meals

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    In the nutrition field, there is a lack of understanding about the impact that dietary chiral composition may have on health, especially regarding cooked meals. Chiral amino acids (AAs) are naturally present in food and their proportion may vary quite a lot. Besides, the D-amino acids (D-AAs) are present in very low concentration compared to L-AAs, so very sensitive methods are required for their accurate quantitation. Moreover, some of them have been described as indicators of quality and different food processes. In this research, we propose a robust method for the absolute quantitation and enantiomeric ratio of 17 D-AAs in cooked meals. The AAs were extracted from 1 g of the homogenised meal with methanol, derivatised with (S)-N-(4-nitrophenoxycarbonyl) phenylalanine methoxyethyl ester ((S)-NIFE) and analysed by RP-LC-MS/MS. The separation was carried out with an Acquity BEH C18 (100 mm x 2.1 mm, 1.7 µm) column at 70 ºC, with 10 mmol/L ammonium bicarbonate in water as eluent A and acetonitrile as eluent B at a 0.3 mL/min flow rate in gradient elution. The MS operated in positive electrospray ionisation method in multiple reaction monitoring (MRM) mode. Isotopically labelled AAs were used as internal standards for the quantitation. The method was validated for 17 D-AAs in the cooked food samples in terms of specificity, linearity, precision, accuracy, matrix effect and stability. LLOQ are 2.0 ng/mL for most of them. Additionally, linearity was also studied for L-AAs. After optimization and validation, the method was applied to real breakfast, lunch and dinner samples of cooked meals (n = 18) that were part of a diet with a very high concordance with WHO dietary guidelines. Level of concentration of major and minor D-AAs have been described per total daily intake and within each of the three main meals. This method can be used for quality control purposes as well as to investigate the role of chiral composition in food and clinical outcomes
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