Composite Polymer Hydrogels with high and Reversible Elongation under Magnetic Stimuli

The field of soft actuators is dominated by elastomers that experience mechanical deformations in response to external stimuli. In this context, magnetic stimuli attract considerable interest because of their easy application, tunability, fast response, remote actuation, and safe penetration in biological environments. Since very recently, research interests in the field are being redirected towards hydrogels, which could virtually replace elastomers, overcoming their limitations and expanding the field of application of soft actuators. The mechanical actuation of hydrogels is a nascent field full of challenges, such as achieving reliable and significant responsiveness. Here we demonstrate that the combination of a physical polymer hydrogel with a dispersed phase consisting of clusters of magnetic particles, results in magnetic hydrogel composites that exhibit high and reversible elongation in response to magnetic stimuli. Our analyses show that this response is strongly dependent on the matrix elasticity, the concentration of magnetic particles, and the particle distribution within the network of polymer nanofibres. Our strategy for the maximization of the response of magnetic hydrogels should be a catalyst for the development of novel applications of composite hydrogels, such as a valve remotely actuated by a magnetic field that we also present here as a proof-of-concept. © 2021 The Author(s).Dr. Mariusz Barczak is acknowledged for help with SEM imaging of iron particles. Ms. Laura Quesada de la Torre is acknowledged for help with design of graphical abstract. This study was supported by project FIS2017-85954-R (Ministerio de Economía, Industria y Competitividad, MINECO, and Agencia Estatal de Investigación, AEI, Spain, cofunded by Fondo Europeo de Desarrollo Regional, FEDER, European Union ). CGV acknowledges financial support by Ministerio de Ciencia, Innovación y Universidades and University of Granada, Spain, for her FPU17/00491 grant. AZ thanks the Russian Science Foundation, project 20-12-00031, for the financial support. LRA thanks the Spanish State Research Agency (Spanish Ministry of Science and Innovation ) through Juan de la Cierva Incorporacion Fellowship ( IJC2018-037951-I ). Funding for open access charge: Universidad de Granada / CBUA

International conference on the healthy effect of virgin olive oil

Ageing represents a great concern in developed countries because the number of people involved and the pathologies related with it, like atherosclerosis, morbus Parkinson, Alzheime's disease, vascular dementia, cognitive decline, diabetes and cancer. Epidemiological studies suggest that a Mediterranean diet (which is rich in virgin olive oil) decreases the risk of cardiovascular disease. The Mediterranean diet, rich in virgin olive oil, improves the major risk factors for cardiovascular disease, such as the lipoprotein profile, blood pressure, glucose metabolism and antithrombotic profile. Endothelial function, inflammation and oxidative stress are also positively modulated. Some of these effects are attributed to minor components of virgin olive oil. Therefore, the definition of the Mediterranean diet should include virgin olive oil. Different observational studies conducted in humans have shown that the intake of monounsaturated fat may be protective against age-related cognitive decline and Alzheimer's disease. Microconstituents from virgin olive oil are bioavailable in humans and have shown antioxidant properties and capacity to improve endothelial function. Furthermore they are also able to modify the haemostasis, showing antithrombotic properties. In countries where the populations fulfilled a typical Mediterranean diet, such as Spain, Greece and Italy, where virgin olive oil is the principal source of fat, cancer incidence rates are lower than in northern European countries. The protective effect of virgin olive oil can be most important in the first decades of life, which suggests that the dietetic benefit of virgin olive oil intake should be initiated before puberty, and maintained through life. The more recent studies consistently support that the Mediterranean diet, based in virgin olive oil, is compatible with a healthier ageing and increased longevity. However, despite the significant advances of the recent years, the final proof about the specific mechanisms and contributing role of the different components of virgin olive oil to its beneficial effects requires further investigations. © 2005 Blackwell Publishing Ltd

Chiral double stapled: O -OPEs with intense circularly polarized luminescence

Intrinsically chiral double stapled ortho-oligo phenylene ethynylenes (o-OPEs) 1 show glum values up to 5.5 × 10-2, the second highest value ever observed for a simple organic molecule (SOM). DFT calculations of molecular spectra and properties encompassing electric and magnetic dipole transition moments account for these observations

Enantiopure Double ortho-Oligophenylethynylene-Based Helical Structures with Circularly Polarized Luminescence Activity

In this paper, we describe the optical and chiroptical properties of an enantiopure multipodal ortho-oligophenylethynylene (S,S,S,S)-1 presenting four chiral sulfoxide groups at the extremes. The presence of these groups together with alkynes allows the coordination with carbophilic Ag(I), and/or oxophilic Zn(II) cations, yielding double helical structures in an enantiopure way. In this sense, different behaviors in absorption, fluorescence, ECD and CPL spectra have been found depending on the stoichiometry and nature of the metal. We have observed that Zn(II) coordination favors an intensity increase of the electronic circular dichroism (ECD) spectra of compound (S,S,S,S)-1 yielding an M-helicity in the ortho-oligophenylene ethynylene (o-OPE) backbone. On the other hand, ECD spectra of final Ag(I) complex shows two different bands with an opposite sign to the free ligand, thus giving the P-helical isomer. In addition, circularly polarized luminescence (CPL) exhibit an enhanced intensity and negative sign in both complexes. Computational studies were also carried out, supporting the experimental results

Optically active Ag(i):: O-OPE helicates using a single homochiral sulfoxide as chiral inducer

In this work we describe the ability of a simple enantiopure sulfoxide group to promote folding of oligo ortho-phenylene ethynylenes (o-OPEs) with one helical sense. A family of foldamers with up to seven triple bonds was synthesized and fully characterized. Moreover, changes in structure and chiroptical properties caused by Ag(i) coordination have been studied by NMR, UV, VCD and ECD measurements. Quantum mechanical DFT calculations support experimental results