Why we use more materials Gutowski, Timothy; Cooper, Daniel; Sahni, Sahil
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
06/2017, Letnik:
375, Številka:
2095
Journal Article
Recenzirano
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In this paper, we review the drivers for the high levels of material use in society, investigating both historical and current trends. We present recent national and global data by different material ...categories and accounting schemes, showing the correlations between materials use and different measures of human well-being. We also present a development narrative to accompany these observed trends, focusing on the strong role materials have played in economic development by industrialization and in the consumer economy. Finally, we speculate on how material efficiency might alter this pattern going forward and whether it is possible to de-couple well-being from material use.
This article is part of the themed issue ‘Material demand reduction’.
In this paper, we review the energy requirements to make materials on a global scale by focusing on the five construction materials that dominate energy used in material production: steel, cement, ...paper, plastics and aluminium. We then estimate the possibility of reducing absolute material production energy by half, while doubling production from the present to 2050. The goal therefore is a 75 per cent reduction in energy intensity. Four technology-based strategies are investigated, regardless of cost: (i) widespread application of best available technology (BAT), (ii) BAT to cutting-edge technologies, (iii) aggressive recycling and finally, and (iv) significant improvements in recycling technologies. Taken together, these aggressive strategies could produce impressive gains, of the order of a 50-56 per cent reduction in energy intensity, but this is still short of our goal of a 75 per cent reduction. Ultimately, we face fundamental thermodynamic as well as practical constraints on our ability to improve the energy intensity of material production. A strategy to reduce demand by providing material services with less material (called 'material efficiency') is outlined as an approach to solving this dilemma.
Cytotoxic T lymphocyte (CTL) and terminal exhausted T lymphocyte (ETL) activities crucially influence immune checkpoint inhibitor (ICI) response. Despite this, the efficacy of ETL and CTL ...transcriptomic signatures for response prediction remains limited. Investigating this across the TCGA and publicly available single-cell cohorts, we find a strong positive correlation between ETL and CTL expression signatures in most cancers. We hence posited that their limited predictability arises due to their mutually canceling effects on ICI response. Thus, we developed DETACH, a computational method to identify a gene set whose expression pinpoints to a subset of melanoma patients where the CTL and ETL correlation is low. DETACH enhances CTL’s prediction accuracy, outperforming existing signatures. DETACH signature genes activity also demonstrates a positive correlation with lymphocyte infiltration and the prevalence of reactive T cells in the tumor microenvironment (TME), advancing our understanding of the CTL cell state within the TME.
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•DETACH successfully decouples CTL and ETL activities in bulk transcriptomic data•Decoupling CTL and ETL enhances ICI response prediction•DETACH is positively associated with tumor-reactive T cell infiltration and activation
Biological sciences; Immunology; Biocomputational method; Computational bioinformatics; Cancer
BackgroundImmune checkpoint blockade (ICB) is a promising cancer therapy; however, response rates remain less than desired (less than ~40%) and resistance often develops.MethodsTo learn more about ...ICB resistance mechanisms, we developed IRIS (Immunotherapy Resistance cell-cell Interaction Scanner), a machine learning method aimed at identifying candidate ligand-receptor interactions (LRI) that are likely to underlie ICB resistance in the tumor microenvironment (TME). Our approach considers two key components that such interactions should fulfill: they should be (1) differentially activated between the pre-treatment and post-treatment non-responder patients, and (2) they should be predictive of ICB response in pre-treatment patients.ResultsWe trained the model on the five largest publicly available melanoma bulk transcriptomics ICB cohorts and demonstrated its superior performance versus two states-of-the-art transcriptomics-based prediction methods (IMPRES and TIDE) in predicting ICB therapy response both in terms of RECIST criteria and patient survival. We further validated our identified resistance relevant LRIs in a melanoma single cell ICB cohort. Strikingly, LRIs highly activated in the pre-treatment group showed stronger predictive power for ICB response compared to the post-treatment non-responder group, which implies a potential negative selection of LRIs by tumors. Notably, many of these LRIs are mediating lymphocyte infiltration within the TME. Reassuringly, we further find a strong correlation between the activity of these LRIs and CD8+ T cells infiltration levels in the TME and are highly enriched in hot tumors in an independent cohort.ConclusionsOverall, these findings point to specific ligand-receptor interactions that mediate ICB resistance via inhibiting lymphocytes infiltration and turning hot tumors to cold ones.
Nano-rutile-titania has been synthesized via a sol–gel route using titanium tetra
n-butoxide as the precursor and ethyl alcohol as the solvent at a low temperature of 80
°C. When synthesized with HCl ...as the catalyst, the powders crystallized without calcination, while the materials prepared using acetylacetone as the catalyst required heating to ∼300
°C to initiate the crystallization. The anatase to rutile transformation temperature decreased with increasing water content.
Remanufactured products that can substitute for new products are generally claimed to save energy. These claims are made from studies that look mainly at the differences in materials production and ...manufacturing. However, when the use phase is included, the situation can change radically. In this Article, 25 case studies for eight different product categories were studied, including: (1) furniture, (2) clothing, (3) computers, (4) electric motors, (5) tires, (6) appliances, (7) engines, and (8) toner cartridges. For most of these products, the use phase energy dominates that for materials production and manufacturing combined. As a result, small changes in use phase efficiency can overwhelm the claimed savings from materials production and manufacturing. These use phase energy changes are primarily due to efficiency improvements in new products, and efficiency degradation in remanufactured products. For those products with no, or an unchanging, use phase energy requirement, remanufacturing can save energy. For the 25 cases, we found that 8 cases clearly saved energy, 6 did not, and 11 were too close to call. In some cases, we could examine how the energy savings potential of remanufacturing has changed over time. Specifically, during times of significant improvements in energy efficiency, remanufacturing would often not save energy. A general design trend seems to be to add power to a previously unpowered product, and then to improve on the energy efficiency of the product over time. These trends tend to undermine the energy savings potential of remanufacturing.
Why we use more materials Gutowski, Timothy; Cooper, Daniel; Sahni, Sahil
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
06/2017, Letnik:
375, Številka:
2095
Journal Article
Recenzirano
In this paper, we review the drivers for the high levels of material use in society, investigating both historical and current trends. We present recent national and global data by different material ...categories and accounting schemes, showing the correlations between materials use and different measures of human well-being. We also present a development narrative to accompany these observed trends, focusing on the strong role materials have played in economic development by industrialization and in the consumer economy. Finally, we speculate on how material efficiency might alter this pattern going forward and whether it is possible to de-couple well-being from material use. This article is part of the themed issue 'Material demand reduction'
In this paper, we review the energy requirements to make materials on a global scale by focusing on the five construction materials that dominate energy used in material production: steel, cement, ...paper, plastics and aluminium. We then estimate the possibility of reducing absolute material production energy by half, while doubling production from the present to 2050. The goal therefore is a 75 per cent reduction in energy intensity. Four technology-based strategies are investigated, regardless of cost: (i) widespread application of best available technology (BAT), (ii) BAT to cutting-edge technologies, (iii) aggressive recycling and finally, and (iv) significant improvements in recycling technologies. Taken together, these aggressive strategies could produce impressive gains, of the order of a 50—56 per cent reduction in energy intensity, but this is still short of our goal of a 75 per cent reduction. Ultimately, we face fundamental thermodynamic as well as practical constraints on our ability to improve the energy intensity of material production. A strategy to reduce demand by providing material services with less material (called 'material efficiency') is outlined as an approach to solving this dilemma.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.
This electronic version was submitted by the student author. The certified thesis is ...available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 155-175).
This research answers a key question - can the materials sector reduce its energy demand by 50% by 2050? Five primary materials of steel, cement, aluminum, paper, and plastic, contribute to 50% or more of the final energy use and CO₂ emissions by industry, and thus are of primary focus. Both technical and demand-side strategies are evaluated to conclude that halving energy demand by 2050 is unlikely given the limitations governed by thermodynamics, scrap availability, and producer/consumer preferences, however some of the strategies analyzed offer encouraging opportunities and should be pursued. The thesis starts with understanding the evolution of material demand as society transforms from a developing to a developed economy. Economic scopes of global, USA, China, and India are assessed. The evolution trends are starkly different. The US shows strong signs of saturation while; both developing economies of China and India do not. The actors of material demand are analyzed to determine what is driving the difference. Results show that consumer income and population have been consistently increasing, but in the second half of the 20th century, the US industry has demanded less material per dollar output, while the US industry output has continued to grow. Collectively they tend to cancel each other, presenting a material saturation phenomenon. For China and India not only is the industry income and industry share of GDP growing, for each unit value addition, industry has continued to demand more material, avoiding demand saturation. One major way to reduce energy used for materials is to decrease the energy intensity of material production. Four technology based strategies are investigated without regard to cost: 1) widespread application of best available technology (BAT), 2) BAT to cutting edge technologies, 3) aggressive recycling, and finally, 4) significant improvements in recycling technologies. Taken together these aggressive strategies could produce impressive gains, on the order of a 20% reduction in energy relative to 2005, but well short of the goal of 50% reduction. Ultimately, we face fundamental thermodynamic and scrap availability constraints. Thus reducing material demand without compromising any service (called "material efficiency") is outlined as an approach to solving this dilemma. One way to increase material efficiency is use products for longer. Remanufacturing can support this by bringing used products back to like-new condition. Remanufactured products that substitute for new products are claimed to save energy. This comes from only looking at the materials production and manufacturing phases of the life cycle. However, when the use phase is included, the situation can change radically. For the 25 product cases we analyzed, 8 cases clearly saved energy, 6 did not, and 11 were too close to call. The drivers for this difference are explained. Thus the energy saving potential of remanufacturing seems complex and uncertain, especially given the trend of powering up of products followed by improvement of their energy efficiencies. As a result focusing remanufacturing efforts on passive products is recommended. Thus scalable material efficiency strategies need to be discovered. However even with the optimistic energy efficiency strategies deployed, in order to achieve the targets, demand increase for the materials needs to be restricted to under 25% of 2005 quantities. This entails that by 2050 we would need to reduce global demand per capita by 10% of today's global average and by 70% of today's US average which is an insurmountable task. Material efficiency strategies hold an impressive technical potential but face severe economic and behavioral challenges that future research needs to overcome.
by Sahil Sahni.
Ph.D.
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