Interaction of a Long Alkyl Chain Protic Ionic Liquid and Water

A combined experimental/theoretical approach has been used to investigate the role of water in modifying the microscopic interactions characterizing the optical response of butyl-ammonium nitrate (BAN) water solutions. Raman spectra, dominated by the signal from the protic ionic liquid, were collected as a function of the water content, and the corresponding spatial organization of the ionic couples, as well as their local arrangement with water molecules, was studied exploiting classical molecular dynamics calculations. High quality spectroscopic data, combined with a careful analysis, revealed that water affects the vibrational spectrum BAN in solution: as the water concentration is increased, peaks assigned to stretching modes show a frequency hardening together with a shape narrowing, whereas the opposite behavior is observed for peaks assigned to bending modes. Calculation results clearly show a nanometric spatial organization of the ionic couples that is not destroyed on increasing the water content at least within an intermediate range. Our combined results show indeed that small water concentrations even increase the local order. Water molecules are located among ionic couples and are closer to the anion than the cation, as confirmed by the computation of the number of H-bonds which is greater for water-anion than for water-cation. The whole results set thus clarifies the microscopic scenario of the BAN-water interaction and underlines the main role of the extended hydrogen bond network among water molecules and nitrate anions.Comment: 27 pages, 10 figure

Role of ionic liquids in protein refolding: native/fibrillar versus treated lysozyme

Several ionic liquids (ILs) are known to revert aggregation processes and improve the in vitro refolding of denatured proteins. In this paper the capacity of a particular class of ammonium based ILs to act as refolding enhancers was tested using lysozyme as a model protein. Raman spectra of ILs treated fibrillar lysozyme as well as lysozyme in its native and fibrillar conformations were collected and carefully analyzed to characterize the refolding extent under the effect of the IL interaction. Results obtained confirm and largely extend the earlier knowledge on this class of protic ILs and indicate Ethyl Ammonium Nitrate (EAN) as the most promising additive for protein refolding. The experiment provides also the demonstration of the high potentiality of Raman spectroscopy as a comprehensive diagnostic tool in this field.Comment: 11 pages, 6 figures, 3 table

Self-Healing and reprocessable oleic acid-based elastomer with dynamic S-S bonds as solvent-free reusable adhesive on copper surface

In the last decade, the application of dynamic covalent chemistry in the field of polymeric materials has become the subject of an increasing number of studies, gaining applicative relevance. This is due to the fact that polymers containing dynamic functions possess a structure that affords reprocessability, recyclability and peculiar self-healing properties inconceivable for “classic” polymer networks. Consequently, the synthesis of a dynamic covalent chemistry-based polymer and its chemical, thermal, and mechanical characterizations are reported in the present research. In particular, oleic acid has been used as starting material to follow the founding principles of the circular economy system and, thanks to the aromatic disulfide component, which is the foundation of the material dynamic characteristics, the obtained polymer resulted as being reprocessable and self-healable. Moreover, the polymer can strongly interact with copper surfaces through the formation of stable Cu-S bonds. Then, the application of the polymer as a solvent-free reusable adhesive for copper was investigated by lap joint shear tests and comparisons with the properties of an analogous material, devoid of the disulfide bonds, were conducted

Digital orphans: Data closure and openness in patient- powered networks

This is the author accepted manuscript. The final version is available from Palgrave Macmillan via the DOI in this record.In this paper, we discuss an issue linked to data-sharing regimes in patient-powered, social-media-based networks, namely that most of the data that patient users share are not used to research scientific issues or the patient voice. This is not a trivial issue, as participation in these networks is linked to openness in data sharing, which would benefits fellow patients and contributes to the public good more generally. Patient-powered research networks are often framed as disrupting research agendas and the industry. However, when data that patients share are not accessible for research, their epistemic potential is denied. The problem is linked to the business models of the organisations managing these networks: models centred on controlling patient data tend to close networks with regard to data use. The constraint on research is at odds with the ideals of a sharing, open and supportive epistemic community that networks’ own narratives evoke. This kind of failure can create peculiar scenarios, such as the emergence of the ‘digital orphans’ of Internet research. By pointing out the issue of data use, this paper informs the discussion about the capacity of patient-powered networks to support research participation and the patient voice.We are indebted to the anonymous reviewers and the editor, who with their supportive and constructive comments helped us to better clarify and highlight the argument of the article. We would like to also thank friends and colleagues who have offered valuable comments and suggestions on early drafts of this paper. We would like to especially thank Barbara Prainsack, Sabina Leonelli, Alena Buyx, and David Teira. This research is funded by the European Research Council (ERC) under the European Union’s Seventh Framework Programme (FP7/2007–2013)/ERC grant agreement number 335925, and the German Federal Ministry of Education and Research (grant number 01GP1311

An X-ray and computational study of liquid pentylammonium nitrate

In this article we report the study of liquid pentylammonium nitrate with Wide Angle X-ray scattering and AIMD simulations. Static and dynamical features were characterized by comparing the experimental X-ray pattern with ab initio molecular dynamics simulation trajectories. From the analysis, we were able to focus our attention on the nature and time duration of the hydrogen bond network established between cation and anion. Such H-bond interactions occur around 2.8 Å, last about 1.55 ps and lead to the loss of degeneracy of the asymmetric stretching normal mode of the anion, with a splitting of about 84 cm−

Impact of Environmental Factors on Stilbene Biosynthesis

Stilbenes are a small family of polyphenolic secondary metabolites that can be found in several distantly related plant species. These compounds act as phytoalexins, playing a crucial role in plant defense against phytopathogens, as well as being involved in the adaptation of plants to abiotic environmental factors. Among stilbenes, trans-resveratrol is certainly the most popular and extensively studied for its health properties. In recent years, an increasing number of stilbene compounds were subjected to investigations concerning their bioactivity. This review presents the most updated knowledge of the stilbene biosynthetic pathway, also focusing on the role of several environmental factors in eliciting stilbenes biosynthesis. The effects of ultraviolet radiation, visible light, ultrasonication, mechanical stress, salt stress, drought, temperature, ozone, and biotic stress are reviewed in the context of enhancing stilbene biosynthesis, both in planta and in plant cell and organ cultures. This knowledge may shed some light on stilbene biological roles and represents a useful tool to increase the accumulation of these valuable compounds

X-Ray Diffraction Studies of Ionic Liquids: from Spectra to Structure and Back

In this chapter we will review the capabilities of X-Ray diffraction experiments in the field of ionic liquids, carried out with the Energy Dispersive variant of the technique. Besides its widespread use in the determination of solid (crystal) structure, in fact, X-Ray diffraction can also be conveniently used to obtain information about the liquid” structure. After the description of data collection and treatment, and a small review of the underlying theory, we will show several examples of the structure factors and the radial distribution functions that can be obtained from dif fraction patterns. These two quantities can be considered as a fingerprint of the ionic liquid, and depend intimately upon the relative disposition of the ions in the liquid phase. Among the most noteworthy spectral features that can be pointed out, we will discuss those deriving from hydrogen-bond interactions, as well as the First Sharp Diffraction Peak (FSDP) that highlight the presence of medium range order (MRO) in the liquid. We will describe several measurements on the protic IL butylammonium nitrate and its water mixtures at different molar fractions, where both features can be found, and show how EDXD patterns can account for the modulation of these features with the composition. In the end, we will show how the change of FSDP spectral feature that occurs during the fusion of alky- lammonium chlorides can be tracked with a multiangular ADXD Rietveld diffrac- tometer

Rice Phytoalexins: Half a Century of Amazing Discoveries; Part I: Distribution, Biosynthesis, Chemical Synthesis, and Biological Activities

Cultivated rice is a staple food for more than half of the world’s population, providing approximately 20% of the world’s food energy needs. A broad spectrum of pathogenic microorganisms causes rice diseases leading to huge yield losses worldwide. Wild and cultivated rice species are known to possess a wide variety of antimicrobial secondary metabolites, known as phytoalexins, which are part of their active defense mechanisms. These compounds are biosynthesized transiently by rice in response to pathogens and certain abiotic stresses. Rice phytoalexins have been intensively studied for over half a century, both for their biological role and their potential application in agronomic and pharmaceutical fields. In recent decades, the growing interest of the research community, combined with advances in chemical, biological, and biomolecular investigation methods, has led to a notable acceleration in the growth of knowledge on rice phytoalexins. This review provides an overview of the knowledge gained in recent decades on the diversity, distribution, biosynthesis, chemical synthesis, and bioactivity of rice phytoalexins, with particular attention to the most recent advances in this research field

Tunnelling in landslide areas connected to deep seated gravitational deformations: An example in Central Alps (northern Italy)

Tunnel excavation in mountainous regions often interacts with landslide phenomena. This paper deals with potential hazards arising from tunnelling in presence of a Deep-Seated Gravitational Slope Deformation (DSGSD), with specific reference to a case study located in Valtellina (northern Italy, Central Alps). In the study area a landslide has shown evidences of activation along the border of a wide DSGSD, where a tunnel has recently been excavated. The conceptual model of both the slope dynamics and the tunnel construction was first reconstructed, by integrating surface and subsurface surveys (from drillings and geophysical investigations to convergence tunnelling measurements, from topographic and inclinometric monitoring to radar interferometry and dendrogeomorphology). Data interpretation showed the presence within the slope of a thick shear zone, characterised by very weak rocks and significant water flows. When the tunnel intercepted this zone, convergences and face instabilities occurred, as well as tunnel inflow; in the meantime, slope deformation developed along the slope. These latter were probably the result of the superimposition of different effects, arising also from the long and heavy rainfall of that period. The investigation of the landslide activity based on dendrochronological analysis confirmed its correlation with rainfall, as well as the contribution of tunnelling. A similar behaviour is also confirmed by the results of stress-strain numerical simulations. Numerical results showed that groundwater rising due to long and heavy rainfall can contribute to slope instability much more than tunnelling itself. Moreover, they showed that the existence of shear and fracture zones connected to the DSGSD determines both an increase in tunnel inflow as well as in tunnel convergences. Actually, fracture and shear zones act as high permeability flow paths within the slope, draining groundwater towards the tunnel and increasing the surface settlements in a wide zone of the slope, worsening the slope stability conditions without triggering the collapse