Membranes with fast and selective ion transport are widely used for water purification and devices for energy conversion and storage including fuel cells, redox flow batteries, and electrochemical reactors.However, it remains challenging to design cost-effective, easily processed ion-conductive membranes with well-defined pore architectures. Here, we report a new approach to designing membranes with narrow molecular-sized channels and hydrophilic functionality that enable fast transport of salt ions and high sizeexclusion selectivity towards small organic molecules. These membranes, based on polymers of intrinsic microporosity (PIMs) containing Tröger's base or amidoxime groups, demonstrate that exquisite control over subnanometer pore structure, the introduction of hydrophilic functional groups, and thickness control all play important roles in achieving fast ion transport combined with high molecular selectivity. These membranes enable aqueous organic flow batteries with high energy efficiency and high capacity retention, suggesting their utility for a variety of energy-related devices and water purification processes.In addition to conventional membrane separation processes 1, 2 , there is a rapidly growing demand for iontransport membranes in applications related to energy 1-3 . With greater reliance on renewable but intermittent energy sources such as solar and wind power, energy conversion and storage technologies are required to integrate low-carbon energy into the power grid. These include electrochemical water splitting and electrolysis for H 2 production 4 , proton-exchange membrane (PEMs) and alkaline fuel cells for energy conversion 5 , electrochemical reduction of CO 2 and N 2 to fuel and chemicals 6 , and scalable redox flow batteries (RFBs) 3,7 . In all of these established and emerging electrochemical processes, ion-selective membranes transport ions whilst isolating the electrochemical reactions in separate cells. In the new generation of RFBs 8-14 , low-cost and high-performance membranes need to have precise selectivity between ions and organic redox-active molecules [15][16][17][18] .Whilst various new electrochemical processes have been developed, the use of expensive commercial ion-exchange membranes, such as the poly(perfluorosulfonic acid) (PFSA)-based Nafion Council through grant agreement number 758370 (ERC-StG-PE5-CoMMaD). Q.S. acknowledges the financial support by Imperial College Department of Chemical Engineering Start-up Fund, seed-funding grant from Institute of Molecular Science and Engineering (IMSE, Imperial College) and seed-funding from EPSRC centres CAM-IES and Energy SuperStore (UK Energy Storage Research Hub). R.T. acknowledges a full PhD scholarship funded by China Scholarship Council. A.W. acknowledges a full PhD scholarship funded by Department of Chemical Engineering at Imperial College. B.P.D. acknowledges the Statoil scholarship. K.E.J. acknowledge the Royal Society University Research Fellowship. A.I.C. and L.C. acknowledge the Leverhulme Trust for supporting the Lev...

How is impact investing evaluated? How can and should it be evaluated? Over the past 5 years, there has been solid progress in developing social impact metrics at the industry-wide, firm and investment levels and the industry is becoming increasingly data-rich. Nevertheless, evaluation practices still tend to focus on counting inputs and outputs, and telling stories. Moreover, an important element is too often underdeveloped, invisible, not explicit or missing altogether. That element is theory of change, an approach and tool drawn from the field of program evaluation. This article reviews cases where theory of change has, in fact, been used to good effect at various levels of the impact investing industry. It also discusses a range of qualitative and quantitative methods which could be usefully blended with the theory of change approach, and affirms the equally important imperatives of accountability and learning across all combinations of methods. The article concludes that a more comprehensive application of theory of change to all levels of the field is required -and especially to the micro-level of individuals, households and communities, where the results of impact investments matter most. Such an approach can help build an impact investing industry that is adaptive, transparent and self-sustaining. To this end, creating an ongoing dialogue between the development evaluation field and the impact investing industry, and designing and launching new education and training initiatives, are key tasks in the years ahead.

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Chondrodermatitis nodularis chronica helicis is a painful nodule of the external ear. These uncommon lesions are most often encountered on the helix in white men older than 40 years, although they also rarely occur on the antihelix in women. The lesions frequently present with exquisite tenderness that interferes with sleep. While the cause of this dermal inflammatory process is not known, long-term trauma or sun damage may play a role. Recurrences often complicate treatment if all sites of inflammation are not eradicated. Surgical treatment is generally recommended, either by wide excision or by deep shave and treatment of the underlying cartilage.

The development of adsorption and membrane-based separation technologies toward more energy and cost efficient processes is a significant engineering problem facing the world today. An example of a process in need of improvement is the separation of C8 aromatics to recover para-xylene, which is the precursor to the widely used monomer terephthalic acid. Molecular simulations were used to investigate whether the separation of C8 aromatics can be carried out by the porous organic cages CC3 and CC13, both of which have been previously used in the fabrication of amorphous thin film membranes. Metadynamics simulations showed significant differences in the energetic barriers to the diffusion of different C8 aromatics through the porous cages, especially for CC3. These differences imply that meta-xylene and ortho-xylene will take significantly longer to enter or leave the cages. Therefore, it may be possible to use membranes composed of these materials to separate ortho-and meta-xylene from para-xylene by size exclusion. Differences in the C8 aromatics' diffusion barriers were caused by their different diffusion mechanisms, while the lower selectivity of CC13 was largely down to its more significant pore breathing. These observations will aid the future design of adsorbents and membrane systems with improved separation performance.