Influence of an ionic comonomer on polymerization-induced self-assembly of diblock copolymers in non-polar media

A series of poly(stearyl methacrylate)-poly(benzyl methacrylate) (PSMA-PBzMA) diblock copolymer nano-objects has been synthesized via reversible addition-fragmentation chain-transfer (RAFT) dispersion polymerization in n-dodecane at 20 wt%. This polymerization-induced self-assembly (PISA) formulation was modified by the incorporation of an anionic monomer, tetradodecylammonium 3-sulfopropyl methacrylate ([NDod 4] +[SPMA] -) into the oil-insoluble PBzMA block. According to the literature (M. J. Derry, et al., Chem. Sci., 2016, 7, 5078-5090), PSMA 18-PBzMA diblock copolymers only form spheres using this formulation for any core degree of polymerization. Unexpectedly, incorporating just a small fraction (<6 mol%) of [NDod 4] +[SPMA] - comonomer into the structure-directing block resulted in the formation of non-spherical diblock copolymer nano-objects, including pure worm-like and vesicular morphologies. However, only spherical micelles could be formed using a longer PSMA 34 stabilizer. These diblock copolymer nano-objects were characterized by transmission electron microscopy, small-angle X-ray scattering, and dynamic light scattering. The bulky nature of the ionic comonomer appears to make it possible to avoid the kinetically-trapped sphere morphology. This study reveals a new approach for tuning the morphology of diblock copolymer nano-objects in non-polar media

Divergent forms of pyroplastic: lessons learned from the M/V X-Press Pearl ship fire

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in James, B., de Vos, A., Aluwihare, L., Youngs, S., Ward, C., Nelson, R., Michel, A., Hahn, M., & Reddy, C. Divergent forms of pyroplastic: lessons learned from the M/V X-Press Pearl ship fire. ACS Environmental Au, 2(5), (2022): 467–479, https://doi.org/10.1021/acsenvironau.2c00020.In late May 2021, the M/V X-Press Pearl container ship caught fire while anchored 18 km off the coast of Colombo, Sri Lanka and spilled upward of 70 billion pieces of plastic or “nurdles” (∼1680 tons), littering the country’s coastline. Exposure to combustion, heat, chemicals, and petroleum products led to an apparent continuum of changes from no obvious effects to pieces consistent with previous reports of melted and burned plastic (pyroplastic) found on beaches. At the middle of this continuum, nurdles were discolored but appeared to retain their prefire morphology, resembling nurdles that had been weathered in the environment. We performed a detailed investigation of the physical and surface properties of discolored nurdles collected on a beach 5 days after the ship caught fire and within 24 h of their arrival onshore. The color was the most striking trait of the plastic: white for nurdles with minimal alteration from the accident, orange for nurdles containing antioxidant degradation products formed by exposure to heat, and gray for partially combusted nurdles. Our color analyses indicate that this fraction of the plastic released from the ship was not a continuum but instead diverged into distinct groups. Fire left the gray nurdles scorched, with entrained particles and pools of melted plastic, and covered in soot, representing partial pyroplastics, a new subtype of pyroplastic. Cross sections showed that the heat- and fire-induced changes were superficial, leaving the surfaces more hydrophilic but the interior relatively untouched. These results provide timely and actionable information to responders to reevaluate cleanup end points, monitor the recurrence of these spilled nurdles, gauge short- and long-term effects of the spilled nurdles to the local ecosystem, and manage the recovery of the spill. These findings underscore partially combusted plastic (pyroplastic) as a type of plastic pollution that has yet to be fully explored despite the frequency at which plastic is burned globally.This work was supported by the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution (WHOI), with funding provided by the Weston Howland Jr. Postdoctoral Scholarship. Additional support was provided by the WHOI Marine Microplastics Catalyst Program, the WHOI Marine Microplastics Innovation Accelerator Program, the WHOI Investment in Science Fund, the March Marine Initiative (a program of March Limited, Bermuda), The Seaver Institute, Gerstner Philanthropies, the Wallace Research Foundation, the Richard Saltonstall Charitable Foundation, the Harrison Foundation, Hollis and Ermine Lovell Charitable Foundation, and the Richard Grand Foundation. AdV was supported by funding from the Schmidt Foundation

INVESTIGATING METHODS OF BLOOD PRESSURE MEASUREMENT: COMPARING CORRELATIONS OF MULTIPLE PULSE TRANSIT TIMES TO BLOOD PRESSURE

Gemstone Team PRESSURECurrently, one in three American adults suffer from high blood pressure, a condition known as hypertension, yet only half have their condition under control (CDC, 2016). Methods of continuous blood pressure measurement have been examined by the team over the past few years. Using five hemodynamic interventions to fluctuate blood pressure, blood pressure data was gathered from 35 healthy adult participants. This data was useful in measuring pulse transit time and determining optimal locations for biosensor placement. Participants were also surveyed to collect public opinion on potential health monitoring devices for future development. Furthermore, the potential of using mobile device applications was examined as an alternative method of retrieving signals and calculating blood pressure. The results from this project indicate that for a mobile device application, the best signals to use for estimating blood pressure are PPG maximum to ECG R-wave, having an average correlation of - r = 0.73 for the systolic blood pressure and -r = 0.71 for the diastolic blood pressure

The rise of policy coherence for development: a multi-causal approach

In recent years policy coherence for development (PCD) has become a key principle in international development debates, and it is likely to become even more relevant in the discussions on the post-2015 sustainable development goals. This article addresses the rise of PCD on the Western donors’ aid agenda. While the concept already appeared in the work of Organisation for Economic Co-operation and Development (OECD) in the early 1990s, it took until 2007 before PCD became one of the Organisation’s key priorities. We adopt a complexity-sensitive perspective, involving a process-tracing analysis and a multi-causal explanatory framework. We argue that the rise of PCD is not as contingent as it looks. While actors such as the EU, the DAC and OECD Secretariat were the ‘active causes’ of the rise of PCD, it is equally important to look at the underlying ‘constitutive causes’ which enabled policy coherence to thrive well

An expanded evaluation of protein function prediction methods shows an improvement in accuracy

Background: A major bottleneck in our understanding of the molecular underpinnings of life is the assignment of function to proteins. While molecular experiments provide the most reliable annotation of proteins, their relatively low throughput and restricted purview have led to an increasing role for computational function prediction. However, assessing methods for protein function prediction and tracking progress in the field remain challenging. Results: We conducted the second critical assessment of functional annotation (CAFA), a timed challenge to assess computational methods that automatically assign protein function. We evaluated 126 methods from 56 research groups for their ability to predict biological functions using Gene Ontology and gene-disease associations using Human Phenotype Ontology on a set of 3681 proteins from 18 species. CAFA2 featured expanded analysis compared with CAFA1, with regards to data set size, variety, and assessment metrics. To review progress in the field, the analysis compared the best methods from CAFA1 to those of CAFA2. Conclusions: The top-performing methods in CAFA2 outperformed those from CAFA1. This increased accuracy can be attributed to a combination of the growing number of experimental annotations and improved methods for function prediction. The assessment also revealed that the definition of top-performing algorithms is ontology specific, that different performance metrics can be used to probe the nature of accurate predictions, and the relative diversity of predictions in the biological process and human phenotype ontologies. While there was methodological improvement between CAFA1 and CAFA2, the interpretation of results and usefulness of individual methods remain context-dependent. Keywords: Protein function prediction, Disease gene prioritizationpublishedVersio

An Expanded Evaluation of Protein Function Prediction Methods Shows an Improvement In Accuracy

Background: A major bottleneck in our understanding of the molecular underpinnings of life is the assignment of function to proteins. While molecular experiments provide the most reliable annotation of proteins, their relatively low throughput and restricted purview have led to an increasing role for computational function prediction. However, assessing methods for protein function prediction and tracking progress in the field remain challenging. Results: We conducted the second critical assessment of functional annotation (CAFA), a timed challenge to assess computational methods that automatically assign protein function. We evaluated 126 methods from 56 research groups for their ability to predict biological functions using Gene Ontology and gene-disease associations using Human Phenotype Ontology on a set of 3681 proteins from 18 species. CAFA2 featured expanded analysis compared with CAFA1, with regards to data set size, variety, and assessment metrics. To review progress in the field, the analysis compared the best methods from CAFA1 to those of CAFA2. Conclusions: The top-performing methods in CAFA2 outperformed those from CAFA1. This increased accuracy can be attributed to a combination of the growing number of experimental annotations and improved methods for function prediction. The assessment also revealed that the definition of top-performing algorithms is ontology specific, that different performance metrics can be used to probe the nature of accurate predictions, and the relative diversity of predictions in the biological process and human phenotype ontologies. While there was methodological improvement between CAFA1 and CAFA2, the interpretation of results and usefulness of individual methods remain context-dependent

Liquid structure of ionic liquids with [NTf₂]⁻ anions, derived from neutron scattering

The liquid structure of three common ionic liquids (ILs) was investigated by neutron scattering for the first time. The ILs were based on the bis(trifluoromethanesulfonyl)imide anion, abbreviated in the literature as [NTf2]− or [TFSI]−, and on the following cations: 1-ethyl-3-methylimidazolium, [C2mim]+; 1-decyl-3-methylimidazolium, [C10mim]+; and trihexyl(tetradecyl)phosphonium, [P666,14]+. Comparative analysis of the three ILs confirmed increased size of nonpolar nanodomains with increasing bulk of alkyl chains. It also sheds light on the cation–anion interactions, providing experimental insight into strength, directionality, and angle of hydrogen bonds between protons on the imidazolium ring, as well as H–C–P protons in [P666,14]+, to oxygen and nitrogen atoms in the [NTf2]−. The new Dissolve data analysis package enabled, for the first time, the analysis of neutron scattering data of ILs with long alkyl chains, in particular, of [P666,14][NTf2]. Results generated with Dissolve were validated by comparing outputs from three different models, starting from three different sets of cation charges, for each of the three ILs, which gave convergent outcomes. Finally, a modified method for the synthesis of perdeuterated [P666,14][NTf2] has been reported, with the aim of reporting a complete set of synthetic and data processing approaches, laying robust foundations that enable the study of the phosphonium ILs family by neutron scattering.<br/

Understanding the effect of pressure on ionic liquid structure

Neutron datasets from ISIS, RB111008

Investigating Cation-Solute Hydrogen Bonding in Ionic Liquids

Neutron datasets from ISIS, RB 1320528 Investigating Cation-Solute Hydrogen Bonding in Ionic Liquids image of ISIS instrument Data collected on the NIMROD instrument at the ISIS facility Abstract: This proposal aims to extend the understanding of uracil-ionic liquid interactions, in particular the C¿H2¿¿¿O=C interaction postulated to exist in a recently published study. The work will extend our understanding of cooperative cation/anion effects in the solubilisation process, and is complementary to our previous studies involving glucose dissolution in ionic liquids. Uracil is one of the four nucleobases of RNA and has uses in drug delivery, as well as being a precursor to various pharmaceuticals itself. As such, its solvation structure in ionic liquids (which are also being considered as potential reaction or solvation media for pharmaceuticals) is of particular interest. We intend to resolve the local structure of the mixture around the cation, anion, and solute, but with particular focus on the ring hydrogens of the ionic liquid cation in order to probe possible H-bonding motifs. Public release date: 31 March 2017 Principal Investigator: Dr Tristan Youngs Experimenter: Mr Adam Turner Experimenter: Professor John Holbrey Experimenter: Dr Fergal Coleman Experimenter: Dr Sarah Norman Experimenter: Ms Jade McCune Experimenter: Dr Gosia Swadzba-Kwasny Experimenter: Ms Caithlin White DOI: 10.5286/ISIS.E.44928045 ISIS Experiment Number: RB1320528 Part Number: 1 download the dataset download the dataset Date of Experiment: 28 March 2014 Publisher: STFC ISIS Neutron and Muon Source Data format: RAW/Nexus Select the data format above to find out more about it. Data Citation The recommended format for citing this dataset in a research publication is as: [author], [date], [title], [publisher], [doi] For Example: Dr Tristan Youngs et al; (2014): Investigating Cation-Solute Hydrogen Bonding in Ionic Liquids, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.4492804

Chain-length dependent organisation in mixtures of hydrogenous and fluorous ionic liquids

As part of an ongoing study of the structure and properties of mixtures of ionic liquids in which one component has a hydrocarbon chain and the other a semiperfluorocarbon chain, we now report a study of the mixtures [C8MIM]1-x[C10MIM-F17]x[Tf2N], [C10MIM]1-x[C8MIM-F13]x[Tf2N] and [C10MIM]1-x[C10MIM-F17]x[Tf2N], where [C8MIM][Tf2N] is 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)imide, [C10MIM][Tf2N] is 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C8MIM-F13][Tf2N] is 1-(1H,1H,2H,2H-perfluorooctyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide and [C10MIM-F17][Tf2N] is 1-(1H,1H,2H,2H-perfluorodecyl)-3-methylimidizolium bis(trifluoromethylsulfonyl)imide. The mixtures were investigated using small-angle X-ray (SAXS) and neutron (SANS) scattering complemented by molecular dynamics simulations (with viscosity and surface tension measurements also possible for the mixtures [C10MIM]1-x[C8MIM-F13]x[Tf2N]). Unlike previous studies of [C8MIM]1-x[C8MIM-F13]x[Tf2N], where no strong evidence of alkyl/fluoroalkyl chain segregation or triphilic behaviour was seen (Elstone et al., J. Phys. Chem. B, 2023, 127, 7394-7407), these new mixtures showed the formation of small aggregates of varying sizes of each component, even though all were co-miscible across the full range of compositions. Thus, while a clear polar non-polar peak (PNPP) was observed at large or small values of x, at intermediate compositions the small-angle neutron scattering at low q was dominated by scattering from these small aggregates, with little or no evidence of the PNPP at some compositions. The origins of this behaviour are discussed in terms of inter-chain interactions