Heterogeneous Catalysis for Fine Chemicals in Dense Phase Carbon Dioxide

An increasing number of fine chemicals is being produced using heterogeneously catalysed reactions in supercritical carbon dioxide with significant improvements in terms of process selectivity and purity of the products thereby obtained. A selection of examples and of recent findings shows the large potential of this technology for the synthetic chemistry of the future.     

Design and eco-innovation: micro-evidence from the Eurobarometer survey

ABSTRACT

This paper investigates the role of design in making firms eco-innovate. Going beyond the ‘packed’ approach of environmental studies about ‘eco-design’, we maintain that the eco-innovative impact of design is correlated with the firm’s decision to invest in it. In turn, design investment is assumed connected with the use firms make of design. By pooling the Eurobarometer 2015 and 2016 surveys, we test for these arguments with respect to a sample of nearly 4500 European and non-European (US and Switzerland) manufacturing firms. Results confirm that the firms’ capacity of eco-innovating increases when they invest in design, also by making this investment dependent on the role of design within the firm. The relationship between eco-innovation and design appears robust with respect to the different kinds of ‘eco-innovators’ that the Eurobarometer enables us to consider, while some interesting variability emerges when splitting the sample by group of countries and industries.     

Poly(Sarcosine) Surface Modification Imparts Stealth‐Like Properties to Liposomes

Circulation lifetime is a crucial parameter for a successful therapy with nanoparticles. Reduction and alteration of opsonization profiles by surface modification of nanoparticles is the main strategy to achieve this objective. In clinical settings, PEGylation is the most relevant strategy to enhance blood circulation, yet it has drawbacks, including hypersensitivity reactions in some patients treated with PEGylated nanoparticles, which fuel the search for alternative strategies. In this work, lipopolysarcosine derivatives (BA‐pSar, bisalkyl polysarcosine) with precise chain lengths and low polydispersity indices are synthesized, characterized, and incorporated into the bilayer of preformed liposomes via a post insertion technique. Successful incorporation of BA‐pSar can be realized in a clinically relevant liposomal formulation. Furthermore, BA‐pSar provides excellent surface charge shielding potential for charged liposomes and renders their surface neutral. Pharmacokinetic investigations in a zebrafish model show enhanced circulation properties and reduction in macrophage recognition, matching the behavior of PEGylated liposomes. Moreover, complement activation, which is a key factor in hypersensitivity reactions caused by PEGylated liposomes, can be reduced by modifying the surface of liposomes with an acetylated BA‐pSar derivative. Hence, this study presents an alternative surface modification strategy with similar benefits as the established PEGylation of nanoparticles, but with the potential of reducing its drawbacks.     

Diagnosis of learner dropout based on learning styles for online distance learning

The amount of data generated by computer systems in Online Distance Learning (ODL) contains rich information. One example of this information we define as the Learner Learning Trail (LLT), which is the sequence of interactions between the students and the virtual environment. Another example is the Learner Learning Style (LLS), which is associated with the student behavior and choices during the learning process. This information can be used to identify learner behavior and learning style. We perceived, after the study of related literature, that the research field of learner diagnosis for ODL does not apply the conjoint use of LLT and LLS. In this article, we propose a model capable of integrating data generated from the behavior of students in ODL with cognitive aspects of them, such as their Learning Styles, by crossing LLT with LLS. We also propose the CPAD method (Collect, Preprocessing, Analysis, Diagnosis), which is implemented by collecting the raw data regarding learning activities, preprocessing the data into structured time sequences, analyzing the sequences regarding the learning styles and using this analysis to diagnose the learner behavior. We selected the dropout to investigate, once the dropout rate in ODL is a real problem in universities around the world. In addition, the dropout is a student decision which can be associated with previous students behaviors. We performed a study with 202 learners to evaluate if learning styles are capable of explaining aspects of the student behavior. The results suggest that Sequential/Global learning style dimension is more capable of explaining the dropout than the other dimensions. Also, we performed four classification experiments to verify how the dimensions of Felder-Silverman Learning Style Model influence the learner diagnosis. We perceived that the Sequential/Global dimension could provide a higher accuracy average with lower variation independently of the diagnosis technique.     

Forest‐based resources as fillers in biobased polyurethane foams

Six fillers from forestry wastes (wood, bark, cones and needles from young pine trees, kraft lignin, and recycled paper sludge from industry wastes) were incorporated into polyurethane (PU)‐based foams prepared via free‐rise pouring method. Variable filler contents (1, 5, and 10 wt %) and NCO/OH ratios (0.6, 0.9, and 1.2) were investigated. A simple mixture (1:3) of castor oil and crude glycerin (byproduct from biodiesel production) was used as biobased polyol. The foam composites were investigated through spectroscopy, morphological, mechanical, and hygroscopic analyses. The addition of fillers decreased water uptake and yielded rigid PU systems with more homogenous cell structure. The 1% and 5% reinforcement wood were the most effective among the studied compositions, with better mechanical and hygroscopic performance, probably due the higher compatibility of the wood with the PU system, which promote urethanic bonds between filler and isocyanate, as indicated by wet chemical results and micrographs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45684.     

Recent Results in the Interpretation of Interference and Lorentz Images of Vortices in Superconductors

The main ideas and approximations underlying the model developed to interpret the principal features of holographic and Fresnel images of superconducting vortices, or fluxons, are briefly reviewed and applied to the exploitation of new experimental setups, like the standard and coherent Foucault techniques. It is also shown how the model can be implemented to interpret effects due to misalignment and/or distortion of the fluxon cores. Finally, the effect of the finite specimen thickness is also taken into account by resorting to the solution of the Ginzburg-Landau equations found by Clem, and by showing that through it a better agreement can be obtained between theoretical and experimental results.     

Realisation barriers in energy efficiency projects in Croatian public buildings: a critic overview and proposals

This paper discusses in detail specific barriers to establishing energy efficiency policies in Croatian public buildings that affect the realisation of energy efficiency projects. Barriers were discovered after years of collaboration with public institutions in Croatia, especially at a local level. Although the information presented in this paper relates specifically to the geographical areas of Splitsko- Dalmatinska and Dubrovacko-Neretvanska counties in Croatia, the research can be generalised to the country as a whole. The paper also analyses the important role of the United Nations Development Programme in encouraging proactive energy efficiency policies in public buildings in Croatia. Finally, a new organisational framework is proposed to eliminate existing barriers and to establish a system which will lead to the effective realisation of energy efficiency projects in buildings. The research presented in this paper should also be useful to countries facing similar barriers to energy investments.     

Insulin Resistance and Cancer: In Search for a Causal Link

Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development.     

Fundamentals and applications of immobilized microfluidic enzymatic reactors

OVERVIEW: Over the last decade, the utility of immobilized microfluidic enzyme reactors (IMERs) has been demonstrated in a wide variety of fields, including medical diagnostics and therapy, biosensors, organic synthesis, drug discovery and many other applications. Of particular interest to the pharmaceutical industry is the potential for high throughput experimentation afforded by these systems, with a view to combinatorial synthesis for drug discovery applications. This article will focus on the current state of IMER systems, including immobilization techniques and microchannel flow generation, with a particular emphasis on applications and future prospects in view of likely directions and market potential of this field. IMPACT: The numerous advantages of attaching enzymes to a solid support, such as reuse of a single batch of enzyme, improved stability and durability, the ability to stop the reaction rapidly by removing the product from the reaction solution and the absence of enzyme contamination of the product are some of the attractive features of such systems. There are, however, a number of issues requiring careful consideration when developing such microsystems, including, but not limited to, surface modifications and exact control of fluid behaviour in microchannels, detection limitations, increased integration, and the reusability of the chips. APPLICATIONS: IMERs have received wide, including commercial, application as diagnostic tools for point‐of‐care applications, and, increasingly, as analytical tools in early drug development. Furthermore, peptide mapping and proteomics have employed IMER systems extensively over the past decade and growth in these areas continues. Copyright © 2011 Society of Chemical Industry     

A One-Dimensional Model for Particulate Deposition and Hydrocarbon Condensation in Exhaust Gas Recirculation Coolers

Cooled exhaust gas recirculation (EGR) is widely used in diesel engines to control engine out NO_x (oxides of nitrogen) emissions. A portion of the exhaust gases is recirculated into the intake manifold of the engine after cooling it through a heat exchanger. EGR cooler heat exchangers, however, tend to lose efficiency and have increased pressure drop as deposit forms on the heat exchanger surface. This adversely affects the combustion process, engine durability, and emissions. In this study, a 1-D model was developed to simulate soot deposition, soot removal, and condensation of several hydrocarbon (HC) species in a circular tube with turbulent gas flow at constant wall temperature. The circular tube, which makes up the computational domain in the model, represents a single channel from any EGR cooler geometry. The model takes into account soot particle deposition due to thermophoresis, diffusion, turbulent impaction, and gravitational drift. However, thermophoresis was found to be the most dominant deposition mechanism for boundary conditions at which EGR coolers typically operate. Soot removal was modeled by considering a force balance between the drag and van der Waals forces. A lognormal distribution of particles was assumed at the tube inlet. The evolution of the particle distribution in the bulk flow along the tube as well as the mass distribution in the deposit layer on the tube walls is predicted by the model. Condensation of six HC species between C₁₅-C₂₄ alkanes was also modeled. Predictions made by the model are in reasonably good agreement with experimental data obtained from a laboratory reactor under the same boundary conditions. There are several assumptions and simplifications built into the model, which can be refined further to improve it.

Copyright 2012 American Association for Aerosol Research