186 research outputs found

    Techno-economic assessment guidelines for CO2 utilization

    Get PDF
    Carbon Capture and Utilization (CCU) is an emerging technology field that can replace fossil carbon value chains, and that has a significant potential to achieve emissions mitigation or even “negative emissions”—however in many cases with challenging technology feasibility and economic viability. Further challenges arise in the decision making for CCU technology research, development, and deployment, in particular when allocating funding or time resources. No generally accepted techno-economic assessment (TEA) standard has evolved, and assessment studies often result in “apples vs. oranges” comparisons, a lack of transparency and a lack of comparability to other studies. A detailed guideline for systematic techno-economic (TEA) and life cycle assessment (LCA) for CCU technologies was developed; this paper shows a summarized version of the TEA guideline, which includes distinct and prioritized (shall and should) rules and which allows conducting TEA in parallel to LCA. The TEA guideline was developed in a co-operative and creative approach with roughly 50 international experts and is based on a systematic literature review as well as on existing best practices from TEA and LCA from the areas of industry, academia, and policy. To the best of our knowledge, this guideline is the first TEA framework with a focus on CCU technologies and the first that is designed to be conducted in parallel to LCA due to aligned vocabulary and assessment steps, systematically including technology maturity. Therefore, this work extends current literature, improving the design, implementation, and reporting approaches of TEA studies for CCU technologies. Overall, the application of this TEA guideline aims at improved comparability of TEA studies, leading to improved decision making and more efficient allocation of funds and time resources for the research, development, and deployment of CCU technologies

    Electron Transfer from Cyt b559 and Tyrosine-D to the S2 and S3 states of the water oxidizing complex in Photosystem II at Cryogenic Temperatures

    Get PDF
    The Mn4CaO5 cluster of photosystem II (PSII) catalyzes the oxidation of water to molecular oxygen through the light-driven redox S-cycle. The water oxidizing complex (WOC) forms a triad with Tyrosine(Z) and P-680, which mediates electrons from water towards the acceptor side of PSII. Under certain conditions two other redox-active components, Tyrosine(D) (Y-D) and Cytochrome b (559) (Cyt b (559)) can also interact with the S-states. In the present work we investigate the electron transfer from Cyt b (559) and Y-D to the S-2 and S-3 states at 195 K. First, Y-D (aEuro cent) and Cyt b (559) were chemically reduced. The S-2 and S-3 states were then achieved by application of one or two laser flashes, respectively, on samples stabilized in the S-1 state. EPR signals of the WOC (the S-2-state multiline signal, ML-S-2), Y-D (aEuro cent) and oxidized Cyt b (559) were simultaneously detected during a prolonged dark incubation at 195 K. During 163 days of incubation a large fraction of the S-2 population decayed to S-1 in the S-2 samples by following a single exponential decay. Differently, S-3 samples showed an initial increase in the ML-S-2 intensity (due to S-3 to S-2 conversion) and a subsequent slow decay due to S-2 to S-1 conversion. In both cases, only a minor oxidation of Y-D was observed. In contrast, the signal intensity of the oxidized Cyt b (559) showed a two-fold increase in both the S-2 and S-3 samples. The electron donation from Cyt b (559) was much more efficient to the S-2 state than to the S-3 state

    Refining human palaeodietary reconstruction using amino acid delta N-15 values of plants, animals and humans.

    Get PDF
    An established method of estimating the trophic level of an organism is through stable isotope analysis of its tissues and those of its diet. This method has been used in archaeology to reconstruct past human diet from the stable nitrogen isotope (d15N) values of human and herbivore bone collagen. However, this approach, using the 15N-enrichment of human bone collagen d15N values over associated herbivore bone collagen d15N values to predict the relative importance of animal protein, relies on the assumptions that: (i) the d15N values of plants consumed by humans and herbivores are identical, and (ii) the 15Nenrichment between diet and consumer is consistent. Bone collagen amino acid d15N values have the potential to tackle these uncertainties, as they constrain the factors influencing bone collagen d15N values. In this study, the d15N values of glutamic acid and phenylalanine in human and herbivore bone collagen isolates from Neolithic sites in Germany, Greece and Turkey were determined by gas chromatography-combustion-isotope ratio mass spectrometry. The fraction of animal protein in total dietary protein consumed by the humans was estimated by: (i) comparing bulk human and herbivore collagen d15N values, (ii) comparing bulk human and herbivore collagen and ancient charred cereal grain d15N values, (iii) comparing human bone collagen d15NGlutamic acid and d15NPhenylalanine values, and (iv) comparing d15NGlutamic acid values of human and herbivore bone collagen and estimated d15NGlutamic acid values of ancient charred cereal grains. Where determined cereal grain d15N values are higher than estimated herbivore forage values, estimates of animal protein consumption are significantly lower, emphasising the importance of the plant nitrogen contribution to human bone collagen. This study also highlights the need for further investigation into: (i) the D15NConsumer-Diet values of glutamic acid and phenylalanine in terrestrial ecosystems, and (ii) D15NGlutamic acid-Phenylalanine values of common plant foods in order to improve the accuracy and more widespread applicability of amino acid-based methods for palaeodietary reconstruction

    Challenges facing an understanding of the nature of low-energy excited states in photosynthesis

    Full text link
    © 2016 Elsevier B.V. While the majority of the photochemical states and pathways related to the biological capture of solar energy are now well understood and provide paradigms for artificial device design, additional low-energy states have been discovered in many systems with obscure origins and significance. However, as low-energy states are naively expected to be critical to function, these observations pose important challenges. A review of known properties of low energy states covering eight photochemical systems, and options for their interpretation, are presented. A concerted experimental and theoretical research strategy is suggested and outlined, this being aimed at providing a fully comprehensive understanding

    Is Mn-Bound Substrate Water Protonated in the S2 State of Photosystem II?

    Get PDF
    In spite of great progress in resolving the geometric structure of the water-splitting Mn4OxCa cluster in photosystem II, the binding sites and modes of the two substrate water molecules are still insufficiently characterized. While time-resolved membrane-inlet mass spectrometry measurements indicate that both substrate water molecules are bound to the oxygen-evolving complex (OEC) in the S2 and S3 states (Hendry and Wydrzynski in Biochemistry 41:13328–13334, 2002), it is not known (1) if they are both Mn-bound, (2) if they are terminal or bridging ligands, and (3) in what protonation state they are bound in the different oxidation states Si (i = 0, 1, 2, 3, 4) of the OEC. By employing 17O hyperfine sublevel correlation (HYSCORE) spectroscopy we recently demonstrated that in the S2 state there is only one (type of) Mn-bound oxygen that is water exchangeable. We therefore tentatively identified this oxygen as one substrate ‘water’ molecule, and on the basis of the finding that it has a hyperfine interaction of about 10 MHz with the electron spin of the Mn4OxCa cluster, we suggest that it is bound as a Mn–O–Mn bridge within a bis-ÎŒ2 oxo-bridged unit (Su et al. in J Am Chem Soc 130:786–787, 2008). Employing pulse electron paramagnetic resonance, 1H/2H Mims electron-nuclear double resonance and 2H-HYSCORE spectroscopies together with 1H/2H-exchange here, we test this hypothesis by probing the protonation state of this exchangeable oxygen. We conclude that this oxygen is fully deprotonated. This result is discussed in the light of earlier reports in the literature

    External validation and adaptation of a dynamic prediction model for patients with high‐grade extremity soft tissue sarcoma

    Get PDF
    Background and Objectives: A dynamic prediction model for patients with soft tissue sarcoma of the extremities was previously developed to predict updated overall survival probabilities throughout patient follow‐up. This study updates and externally validates the dynamic model. Methods: Data from 3826 patients with high‐grade extremity soft tissue sarcoma, treated surgically with curative intent were used to update the dynamic PERsonalised SARcoma Care (PERSARC) model. Patients were added to the model development cohort and grade was included in the model. External validation was performed with data from 1111 patients treated at a single tertiary center. Results: Calibration plots show good model calibration. Dynamic C‐indices suggest that the model can discriminate between high‐ and low‐risk patients. The dynamic C‐indices at 0, 1, 2, 3, 4, and 5 years after surgery were equal to 0.697, 0.790, 0.822, 0.818, 0.812, and 0.827, respectively. Conclusion: Results from the external validation show that the dynamic PERSARC model is reliable in predicting the probability of surviving an additional 5 years from a specific prediction time point during follow‐up. The model combines patient‐, treatment‐specific and time‐dependent variables such as local recurrence and distant metastasis to provide accurate survival predictions throughout follow‐up and is available through the PERSARC app.Peer reviewe

    Age-related differences of oncological outcomes in primary extremity soft tissue sarcoma: a multistate model including 6260 patients

    Get PDF
    Purpose: No studies extensively compared the young adults (YA, 18-39 years), middle-aged (40-69 years), and elderly (≄70 years) population with primary high-grade extremity soft tissue sarcoma (eSTS). This study aimed to determine whether the known effect of age on overall survival (OS) and disease progression can be explained by differences in tumour characteristics and treatment protocol among the YA, middle-aged and elderly population in patients with primary high-grade eSTS treated with curative intent. Methods: In this retrospective multicentre study, inclusion criteria were patients with primary high-grade eSTS of 18 years and older, surgically treated with curative intent between 2000 and 2016. Cox proportional hazard models and a multistate model were used to determine the association of age on OS and disease progression. Results: A total of 6260 patients were included in this study. YA presented more often after 'whoops'-surgery or for reresection due to residual disease, and with more deep-seated tumours. Elderly patients presented more often with grade III and larger (≄10 cm) tumours. After adjustment for the imbalance in tumour and treatment characteristics the hazard ratio for OS of the middle-aged population is 1.47 (95% confidence interval [CI]: 1.23-1.76) and 3.13 (95% CI: 2.59-3.78) in the elderly population, compared with YA. Discussion: The effect of age on OS could only partially be explained by the imbalance in the tumour characteristics and treatment variables. The threefold higher risk of elderly could, at least partially, be explained by a higher other-cause mortality. The results might also be explained by a different tumour behaviour or suboptimal treatment in elderly compared with the younger population. Keywords: Adolescents and young adults; Elderly; Extremities; Metastasis; Middle-aged; Recurrence; Soft tissue sarcoma; Survival.Peer reviewe

    Interpreting ancient food practices:Stable isotope and molecular analyses of visible and absorbed residues from a year-long cooking experiment

    Get PDF
    Chemical analyses of carbonized and absorbed organic residues from archaeological ceramic cooking vessels can provide a unique window into the culinary cultures of ancient people, resource use, and environmental effects by identifying ingredients used in ancient meals. However, it remains uncertain whether recovered organic residues represent only the final foodstuffs prepared or are the accumulation of various cooking events within the same vessel. To assess this, we cooked seven mixtures of C3 and C4 foodstuffs in unglazed pots once per week for one year, then changed recipes between pots for the final cooking events. We conducted bulk stable-isotope analysis and lipid residue analysis on the charred food macro-remains, carbonized thin layer organic patina residues and absorbed lipids over the course of the experiment. Our results indicate that: (1) the composition of charred macro-remains represent the final foodstuffs cooked within vessels, (2) thin-layer patina residues represent a mixture of previous cooking events with bias towards the final product(s) cooked in the pot, and (3) absorbed lipid residues are developed over a number of cooking events and are replaced slowly over time, with little evidence of the final recipe ingredients

    The Cultural Project : Formal Chronological Modelling of the Early and Middle Neolithic Sequence in Lower Alsace

    Get PDF
    Starting from questions about the nature of cultural diversity, this paper examines the pace and tempo of change and the relative importance of continuity and discontinuity. To unravel the cultural project of the past, we apply chronological modelling of radiocarbon dates within a Bayesian statistical framework, to interrogate the Neolithic cultural sequence in Lower Alsace, in the upper Rhine valley, in broad terms from the later sixth to the end of the fifth millennium cal BC. Detailed formal estimates are provided for the long succession of cultural groups, from the early Neolithic Linear Pottery culture (LBK) to the Bischheim Occidental du Rhin Supérieur (BORS) groups at the end of the Middle Neolithic, using seriation and typology of pottery as the starting point in modelling. The rate of ceramic change, as well as frequent shifts in the nature, location and density of settlements, are documented in detail, down to lifetime and generational timescales. This reveals a Neolithic world in Lower Alsace busy with comings and goings, tinkerings and adjustments, and relocations and realignments. A significant hiatus is identified between the end of the LBK and the start of the Hinkelstein group, in the early part of the fifth millennium cal BC. On the basis of modelling of existing dates for other parts of the Rhineland, this appears to be a wider phenomenon, and possible explanations are discussed; full reoccupation of the landscape is only seen in the Grossgartach phase. Radical shifts are also proposed at the end of the Middle Neolithic

    A bottom-up view of food surplus: using stable carbon and nitrogen isotope analysis to investigate agricultural strategies and diet at Bronze Age Archontiko and Thessaloniki Toumba, northern Greece

    Get PDF
    We use stable isotope analysis of crop, faunal and human remains to investigate agricultural strategies and diet at EBA-LBA Archontiko and MBA-LBA Thessaloniki Toumba. Crop production strategies varied between settlements, phases and species; flexibility is also apparent within the crop stores of individual houses. Escalating manuring intensity at LBA Thessaloniki Toumba coincides with large co-residential ‘blocks’ geared towards hoarding of agricultural surpluses, spectacularly preserved by fire at nearby LBA Assiros Toumba. Faunal isotope values reflect a range of feeding strategies, including probable herding of cattle on C4-rich coastal salt marshes, evident at Archontiko through to the LBA alongside bulk cockle harvesting. Palaeodietary analysis of LBA humans at Thessaloniki Toumba indicates that C3 crops represent the only plausible staples. Millet was a minor food but may have played a particular role in the sub-adult diet. Meat probably featured in supra-household food sharing and hospitality, associated with Mycenaean-style tableware in the LBA
    • 

    corecore