The sustainable materials roadmap

Over the past 150 years, our ability to produce and transform engineered materials has been responsible for our current high standards of living, especially in developed economies. However, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of the economy, energy, and climate. We are at the point where something must drastically change, and it must change now. We must create more sustainable materials alternatives using natural raw materials and inspiration from nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments (LCAs) based on reliable and relevant data to quantify sustainability. We need to seriously start thinking of where our future materials will come from and how could we track them, given that we are confronted with resource scarcity and geographical constrains. This is particularly important for the development of new and sustainable energy technologies, key to our transition to net zero. Currently 'critical materials' are central components of sustainable energy systems because they are the best performing. A few examples include the permanent magnets based on rare earth metals (Dy, Nd, Pr) used in wind turbines, Li and Co in Li-ion batteries, Pt and Ir in fuel cells and electrolysers, Si in solar cells just to mention a few. These materials are classified as 'critical' by the European Union and Department of Energy. Except in sustainable energy, materials are also key components in packaging, construction, and textile industry along with many other industrial sectors. This roadmap authored by prominent researchers working across disciplines in the very important field of sustainable materials is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the sustainable materials community. In compiling this roadmap, we hope to aid the development of the wider sustainable materials research community, providing a guide for academia, industry, government, and funding agencies in this critically important and rapidly developing research space which is key to future sustainability.journal articl

A Test of Highly Optimized Tolerance Reveals Fragile Cell-Cycle Mechanisms Are Molecular Targets in Clinical Cancer Trials

Robustness, a long-recognized property of living systems, allows function in the face of uncertainty while fragility, i.e., extreme sensitivity, can potentially lead to catastrophic failure following seemingly innocuous perturbations. Carlson and Doyle hypothesized that highly-evolved networks, e.g., those involved in cell-cycle regulation, can be resistant to some perturbations while highly sensitive to others. The “robust yet fragile” duality of networks has been termed Highly Optimized Tolerance (HOT) and has been the basis of new lines of inquiry in computational and experimental biology. In this study, we tested the working hypothesis that cell-cycle control architectures obey the HOT paradigm. Three cell-cycle models were analyzed using monte-carlo sensitivity analysis. Overall state sensitivity coefficients, which quantify the robustness or fragility of a given mechanism, were calculated using a monte-carlo strategy with three different numerical techniques along with multiple parameter perturbation strategies to control for possible numerical and sampling artifacts. Approximately 65% of the mechanisms in the G1/S restriction point were responsible for 95% of the sensitivity, conversely, the G2-DNA damage checkpoint showed a much stronger dependence on a few mechanisms; ∼32% or 13 of 40 mechanisms accounted for 95% of the sensitivity. Our analysis predicted that CDC25 and cyclin E mechanisms were strongly implicated in G1/S malfunctions, while fragility in the G2/M checkpoint was predicted to be associated with the regulation of the cyclin B-CDK1 complex. Analysis of a third model containing both G1/S and G2/M checkpoint logic, predicted in addition to mechanisms already mentioned, that translation and programmed proteolysis were also key fragile subsystems. Comparison of the predicted fragile mechanisms with literature and current preclinical and clinical trials suggested a strong correlation between efficacy and fragility. Thus, when taken together, these results support the working hypothesis that cell-cycle control architectures are HOT networks and establish the mathematical estimation and subsequent therapeutic exploitation of fragile mechanisms as a novel strategy for anti-cancer lead generation

Roadmap for a sustainable circular economy in lithium-ion and future battery technologies

The market dynamics, and their impact on a future circular economy for lithium-ion batteries (LIB), are presented in this roadmap, with safety as an integral consideration throughout the life cycle. At the point of end-of-life (EOL), there is a range of potential options—remanufacturing, reuse and recycling. Diagnostics play a significant role in evaluating the state-of-health and condition of batteries, and improvements to diagnostic techniques are evaluated. At present, manual disassembly dominates EOL disposal, however, given the volumes of future batteries that are to be anticipated, automated approaches to the dismantling of EOL battery packs will be key. The first stage in recycling after the removal of the cells is the initial cell-breaking or opening step. Approaches to this are reviewed, contrasting shredding and cell disassembly as two alternative approaches. Design for recycling is one approach that could assist in easier disassembly of cells, and new approaches to cell design that could enable the circular economy of LIBs are reviewed. After disassembly, subsequent separation of the black mass is performed before further concentration of components. There are a plethora of alternative approaches for recovering materials; this roadmap sets out the future directions for a range of approaches including pyrometallurgy, hydrometallurgy, short-loop, direct, and the biological recovery of LIB materials. Furthermore, anode, lithium, electrolyte, binder and plastics recovery are considered in order to maximise the proportion of materials recovered, minimise waste and point the way towards zero-waste recycling. The life-cycle implications of a circular economy are discussed considering the overall system of LIB recycling, and also directly investigating the different recycling methods. The legal and regulatory perspectives are also considered. Finally, with a view to the future, approaches for next-generation battery chemistries and recycling are evaluated, identifying gaps for research. This review takes the form of a series of short reviews, with each section written independently by a diverse international authorship of experts on the topic. Collectively, these reviews form a comprehensive picture of the current state of the art in LIB recycling, and how these technologies are expected to develop in the future

Net-zero solutions and research priorities in the 2020s

Key messages • Technological, societal and nature-based solutions should work together to enable systemic change towards a regenerative society, and to deliver net-zero greenhouse gas (GHG) emissions. • Prioritise research into efficient, low-carbon and carbon-negative solutions for sectors that are difficult to decarbonise; i.e. energy storage, road transport, shipping, aviation and grid infrastructure. • Each solution should be assessed with respect to GHG emissions reductions, energy efficiency and societal implications to provide a basis for developing long-term policies, maximising positive impact of investment and research effort, and guiding industry investors in safe and responsible planning

Search for charged Higgs bosons through the violation of lepton universality in t¯t events using pp collision data at ps = 7 TeV with the ATLAS experiment

In several extensions of the Standard Model, the top quark can decay into a bottom quark and a light charged Higgs boson H+, t → bH+, in addition to the Standard Model decay t → bW. Since W bosons decay to the three lepton generations equally, while H+ may predominantly decay into τν, charged Higgs bosons can be searched for using the violation of lepton universality in top quark decays. The analysis in this paper is based on 4.6 fb−1 of proton-proton collision data at √s = 7 TeV collected by the ATLAS experiment at the Large Hadron Collider. Signatures containing leptons (e or μ) and/or a hadronically decaying τ (τhad) are used. Event yield ratios between e+τhad and e+μ, as well as between μ+τhad and μ+e, final states are measured in the data and compared to predictions from simulations. This ratio-based method reduces the impact of systematic uncertainties in the analysis. No significant deviation from the Standard Model predictions is observed. With the assumption that the branching fraction B(H+ → τν) is 100%, upper limits in the range 3.2%–4.4% can be placed on the branching fraction B(t → bH+) for charged Higgs boson masses mH+ in the range 90–140GeV. After combination with results from a search for charged Higgs bosons in t¯t decays using the τhad+jets final state, upper limits on B(t → bH+) can be set in the range 0.8%–3.4%, for mH+ in the range 90–160GeV

Search for new particles in events with one lepton and missing transverse momentum in pp collisions at √s = 8 TeV with the ATLAS detector

This paper presents a search for new particles in events with one lepton (electron or muon) and missing transverse momentum using 20.3 fb−¹ of proton-proton collision data at √s=8 TeV recorded by the ATLAS experiment at the Large Hadron Collider. No significant excess beyond Standard Model expectations is observed. A W′ with Sequential Standard Model couplings is excluded at the 95% confidence level for masses up to 3.24 TeV. Excited chiral bosons (W*) with equivalent coupling strengths are excluded for masses up to 3.21 TeV. In the framework of an effective field theory limits are also set on the dark matter-nucleon scattering cross-section as well as the mass scale M* of the unknown mediating interaction for dark matter pair production in association with a leptonically decaying W

Measurement of the W-boson helicity in top-quark decays from t(t)over-bar production in lepton plus jets events in pp collisions at √s=7 TeV

This is the pre-print version of the final published article that can be accessed at the link below.The W-boson helicity fractions in top-quark decays are measured with tt events in the lepton+jets final state, using proton-proton collisions at a centre-of-mass energy of 7 TeV, collected in 2011 with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 5.0 fb-1. The measured fractions of longitudinal, left-, and right-handed helicity are F0 = 0.682 0.030 (stat.) 0.033 (syst.), FL = 0.310 0.022 (stat.) 0.022 (syst.), and FR = 0.008 0.012 (stat.) 0.014 (syst.), consistent with the standard model predictions. The measured fractions are used to probe the existence of anomalous Wtb couplings. Exclusion limits on the real components of the anomalous couplings gL, gR are also derived

Measurement of the tt¯ production cross-section using eμ events with b-tagged jets in pp collisions at √s=7 and 8 TeV with the ATLAS detector

The inclusive top quark pair (tt¯) production cross-section σtt¯ has been measured in proton–proton collisions at √s=7 TeV and √s=8 TeV with the ATLAS experiment at the LHC, using tt¯ events with an opposite-charge eμ pair in the final state. The measurement was performed with the 2011 7 TeV dataset corresponding to an integrated luminosity of 4.6 fb−1 and the 2012 8 TeV dataset of 20.3 fb−1. The numbers of events with exactly one and exactly two b-tagged jets were counted and used to simultaneously determine σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section was measured to be: σtt¯=182.9±3.1±4.2±3.6±3.3 pb (s=7 TeV)and σtt¯=242.4±1.7±5.5±7.5±4.2 pb (s=8 TeV), where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, knowledge of the integrated luminosity and of the LHC beam energy. The results are consistent with recent theoretical QCD calculations at next-to-next-to-leading order. Fiducial measurements corresponding to the experimental acceptance of the leptons are also reported, together with the ratio of cross-sections measured at the two centre-of-mass energies. The inclusive cross-section results were used to determine the top quark pole mass via the dependence of the theoretically predicted cross-section on mtpole giving a result of mtpole=172.9−2.6+2.5 GeV. By looking for an excess of tt¯ production with respect to the QCD prediction, the results were also used to place limits on the pair-production of supersymmetric top squarks t~1 with masses close to the top quark mass, decaying via t~1→tχ~10 to predominantly right-handed top quarks and a light neutralino χ~10, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 177 GeV are excluded at the 95 % confidence level

Measurement of the Z/γ* boson transverse momentum distribution in pp collisions at √s = 7 TeV with the ATLAS detector

This paper describes a measurement of the Z/γ* boson transverse momentum spectrum using ATLAS proton-proton collision data at a centre-of-mass energy of √s=7 TeV at the LHC. The measurement is performed in the Z/γ* → e+e− and Z/γ* → μ+μ− channels, using data corresponding to an integrated luminosity of 4.7 fb−¹. Normalized differential cross sections as a function of the Z/γ* boson transverse momentum are measured for transverse momenta up to 800 GeV. The measurement is performed inclusively for Z/γ* rapidities up to 2.4, as well as in three rapidity bins. The channel results are combined, compared to perturbative and resummed QCD calculations and used to constrain the parton shower parameters of Monte Carlo generators

Search for the standard model Higgs boson produced in association with a top-quark pair in pp collisions at the LHC

This is the pre-print version of the final published paper that is available from the link below.A search for the standard model Higgs boson produced in association with a top-quark pair is presented using data samples corresponding to an integrated luminosity of 5.0 fb-1 (5.1 fb-1) collected in pp collisions at the center-of-mass energy of 7TeV (8TeV). Events are considered where the top-quark pair decays to either one lepton+jets (tt→lvqq’bb) or dileptons [tt→l(+)vl(-)vbb], l being an electron or a muon. The search is optimized for the decay mode H → bb. The largest background to the ttH signal is top-quark pair production with additional jets. Artificial neural networks are used to discriminate between signal and background events. Combining the results from the 7TeV and 8TeV samples, the observed (expected) limit on the cross section for Higgs boson production in association with top quark pairs for a Higgs boson mass of 125 GeV is 5.8 (5.2) times the standard model expectatio