Compartments for Synthetic Cells: Osmotically Assisted Separation of Oil from Double Emulsions in a Microfluidic Chip

Liposomes are used in synthetic biology as cell-like compartments and their microfluidic production through double emulsions allows for efficient encapsulation of various components. However, residual oil in the membrane remains a critical bottleneck for creating pristine phospholipid bilayers. It has been discovered that osmotically driven shrinking leads to detachment of the oil drop. Separation inside a microfluidic chip has been realized to automate the procedure, which allows for controlled continuous production of monodisperse liposomes.     

Probability density functions for bubble size distribution in air–water systems in stirred tanks

Bubble size distribution (BSD) is relevant to the design of gas–liquid systems, as it determines the interfacial area available in heat and mass transfer processes. Although data on BSD in stirred aerated tanks are available, a systematic comparison of alternative modeling functions for these data is lacking. In this work, BSDs obtained in air–water dispersions in a stirred aerated tank with a Rushton turbine and BSDs available in the literature for similar systems were modeled by 14 empirical probability density functions (PDFs). It was found that both the distribution of Nukiyama–Tanasawa with three adjustable parameters and the Rosin–Rammler distribution with two adjustable parameters reasonably fit original and literature BSDs. It is also concluded that it is possible to correlate the PDF parameters with the power dissipated by the agitator in the liquid phase, allowing the BSD to be modeled with only two parameters in a range of dissipated power from 0.5 to 2.3?kW/m³. BSDs thus modeled provide good predictions of average bubble size.     

Optimal Self-Scheduling of a Tidal Power Plant

This paper considers the optimal operation of a tidal power producer. Different generating cycles for the tidal power plant are considered. The paper provides a tool for self-scheduling of the tidal power producer so that the maximum profit from selling energy in an electricity market is achieved, while meeting all technical operating constraints of the tidal power plants. The formulation provided is also valid in a centralized operation framework; the only change needed is to define a different cost-related objective function. The resulting optimization problem, which is mixed-integer and linear, is solved using commercially available software. Results from realistic simulations are reported and analyzed.     

Differentiation of Leydig cells in the Mongolian gerbil

Information on postnatal Leydig cell (LC) differentiation in the Mongolian gerbil has been unavailable. Therefore, current investigation was designed to examine LC lineage differentiationin this rodent, from birth to adulthood. Gerbil testes at 1 day, 1–7 weeks (w), 2 and 3 months of age were conventionally processed by light and transmission electron microscopy. Immunocytochemistry for specific markers of steroidogenic enzymes, namely 3β‐hydroxysteroid dehydrogenase (3β‐HSD) and 11β‐hydroxysteroid steroid dehydrogenase 1 (11β‐HSD1) and also for androgen receptor (AR) was performed. The establishment of adult Leydig cell populations (ALC) during testis maturation in the gerbil follows the pattern previously described in other mammalian species, with the four progressive stages of differentiation. The LC progenitors were identified at second w by 3β‐HSD expression; the first newly formed ALC were recognized at fourth w whereas immature ALC appeared at fifth w. The latter were recognized by abundance of cytoplasmic lipid, in addition to expression of 11β‐HSD1 and intense nuclear AR immunoreaction. Mature ALC in gerbil exhibited irregular eccentric nuclei and a cytoplasmic canaliculus in the perinuclear area. Only one third of mature ALC in adult gerbils showed a high expression of 11β‐HSD1 and AR expression was highly variable among them. In conclusion, the process of differentiation of ALC population in gerbil follows the pattern previously established for other rodents. However, the resulting mature ALC are strikingly different due their singular asymmetric morphology and presence of a cytoplasmic canaliculus and as well as their functional heterogeneity. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc.     

Deterioration in XI–XIV century arab ramparts (Granada, Spain)

The causes and mechanisms of degradation in the ramparts of Granada, erected in the XIth to XIVth centuries, have been studied via XRD, XRF, ICP, SEM, optical microscopy, and Hg-intrusion porosimetry. We have analysed structures from different periods, including inner material and outer surfaces, ornamentation, and possible source quarries. The technique employed in these ramparts was packed-earth construction, which we have divided into three different types depending on the proportions and layering or mixing of the binder with earth. The use of these distinct methods seems to be linked to diverse historical periods, also conditioned by the economic prosperity of the Kingdom of Granada at the time. The main weathering agent is water, in different states and compositions. It ruins the poorly compacted rendering mortar by provoking the loss by dissolution of calcite, which constitutes the cementing agent, with consequent disgregation. The water also facilitates the circulation of salts and binder-alkali reactions, thus leading to changes in volume. It is therefore essential to protect such walls against the action of water in order to conserve them. Other factors to be taken into consideration include destruction or alteration due to urban development, inappropriate restorations, earthquakes, and environmental pollution.

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Résumé Nous avons étudié les causes et les mécanismes de la détérioration des murailles de Grenade, construites du XI^e au XIV^e siècles par différentes techniques: DRX, FRX, PCI, MEB, microscope optique et porosimètre à mercure. L'étude couvre des structures de différentes périodes, incluant le matériau interne, les surfaces externes, l'ornementation et les carrières d'origines probables. Pour ces murailles, on a utilisé une construction à base de terre. Il a été identifié trois types différents selon les proportions et les mélanges du liant et de la terre. L'emploi de ces différentes méthodes semble être lié aux diverses époques historiques, en fonction de la prospérité économique du Royaume de Grenade selon l'époque. L'eau constitue le principal facteur de vieillissement. Elle est à l'origine de la dégradation de l'enduit faiblement compacté, en provoquant une perte de calcite, agent de cimentation, par une dissolution induisant une désagrégation de l'enduit. L'eau facilite aussi la circulation des sels et induisant les réactions du type liant-alcali et des changements de volume. Il est donc essentiel de protéger ce type de murs de l'action de l'eau pour mieux les préserver. D'autres éléments à prendre en considération sont la destruction ou altération à cause du développement urbain, les restaurations inadaptées, les tremblements de terre et la pollution de l'environnement.

     

Drivers and consequences of an innovative technology assimilation in the supply chain: cloud computing and supply chain integration

Cloud Computing are innovative technologies that are being applied in the main business functions in the supply chain. This study aims to reveal the determinant factors (drivers and a relevant outcome) of the level of use or assimilation of Cloud Computing in the supply chain. In order to test three hypotheses we conducted an empirical study in 484 companies from sectors in an intermediate position in the supply chain. The data gathering method consisted of a telephone survey using a computerised system (CATI). We used structural equation modelling (SEM) to test the hypotheses. The empirical study reveals that Advanced Manufacturing Technologies pursuing the internal efficiency of the supply chain (Intra-organisational IT) and IT for capabilities in e-business/e-commerce seeking external connection of the supply chain with other companies (Inter-organisational IT) are drivers of Cloud Computing assimilation. Furthermore, supply chain integration is one of the major consequences of Cloud Computing assimilation in the supply chain.     

An architecture for making recommendations to courseware authors using association rule mining and collaborative filtering

Nowadays we find more and more applications for data mining techniques in e-learning and web-based adaptive educational systems. The useful information discovered can be used directly by the teacher or author of the course in order to improve instructional/learning performance. This can, however, imply a lot of work for the teacher who can greatly benefit from the help of educational recommender systems for doing this task. In this paper we propose a system oriented to find, share and suggest the most appropriate modifications to improve the effectiveness of the course. We describe an iterative methodology to develop and carry out the maintenance of web-based courses to which we have added a specific data mining step. We apply association rule mining to discover interesting information through students’ usage data in the form of IF-THEN recommendation rules. We have also used a collaborative recommender system to share and score the recommendation rules obtained by teachers with similar profiles along with other experts in education. Finally, we have carried out experiments with several real groups of students using a web-based adaptive course. The results obtained demonstrate that the proposed architecture constitutes a good starting point to future investigations in order to generalize the results over many course contents.     

The traveling tournament problem with predefined venues

Sports scheduling is a very attractive application area not only because of the interesting mathematical structures of the problems, but also due to their importance in practice and to the big business that sports have become. In this paper, we introduce the Traveling Tournament Problem with Predefined Venues, which consists in scheduling a compact single round robin tournament with a predefined venue assignment for each game (i.e., the venue where each game takes place is known beforehand) while the total distance traveled by the teams is minimized. Three integer programming formulations are proposed and compared. We also propose some simple enumeration strategies to generate feasible solutions to real-size instances in a reasonable amount of time. We show that two original enumeration strategies outperform an improvement heuristic embedded within a commercial solver. Comparative numerical results are presented.     

Social Media Use for News and Individuals' Social Capital,Civic Engagement and Political Participation

Recently, scholars tested how digital media use for informational purposes similarly contributes to foster democratic processes and the creation of social capital. Nevertheless, in the context of today's socially‐networked‐society and the rise of social media applications (i.e., Facebook) new perspectives need to be considered. Based on U.S. national data, results show that after controlling for demographic variables, traditional media use offline and online, political constructs (knowledge and efficacy), and frequency and size of political discussion networks, seeking information via social network sites is a positive and significant predictor of people's social capital and civic and political participatory behaviors, online and offline.     

Corrosion behaviour of a dissimilar joint TIG weld between austenitic AISI 316L and ferritic AISI 444 stainless steels

The AISI 444 stainless steel (SS) has become an option to substitute the AISI 316L SS because of its low cost and satisfactory corrosion resistance. However, the use of AISI 444 alloy tubes in heat exchangers causes the welding of a dissimilar joint. The aim of this study was evaluate the corrosion resistance of the tube-to-tubesheet welded by a TIG process composed of AISI 316L and AISI 444. Preparation of samples was executed through replication of tube-to-tubesheet joints. In order to test the corrosion resistance of the welded joint, the following tests were applied: sensitisation, mass loss from room temperature up to 90 °C and electrochemical corrosion tests in 0.5 mol/L HCl and 0.5 mol/L H₂SO₄ electrolytes. The results have shown that the dissimilar joint suffers galvanic corrosion with increased degradation of the heat-affected zone of the AISI 444 tube. Nevertheless, the mechanisms of localised corrosion (pit and intergranular) were more active in the AISI 316L alloy. It is concluded that the dissimilar joint showed better corrosion resistance than the welded joint composed solely of AISI 316L at temperatures up to 70 °C, as the conditions observed in this work.