725 research outputs found
Vimentin Intermediate Filament Softening - Recovery Behavior and Post-Translational Modifications
The capability of eukaryotic cells to resist large deformations, to transport intracellular cargo and to adapt the cell shape, for example during migration, depends on the cytoskeleton, a composite network of three types of filamentous proteins: actin filaments, microtubules and intermediate filaments (IFs). The physical properties of cells are controlled by the architecture of these cytsokeletal filaments and networks and different expression levels of various proteins or protein modifications lead to variation of the mechanical properties of cells. The individual components of the cytoskeleton differ in their diameter, their assembly process, their mechanical properties and interaction partners as well as their function. Whereas actin and tubulin are expressed throughout all cell types, different types of IF proteins are expressed in a cell-type specific manner. In general, IFs are believed to function as supporters for the mechanical resistance of cells. Over the past few years, particularly the role of the IF protein vimentin gained importance for its role in cell mechanics. Furthermore, different IF proteins seem to be highly involved in diseases such as cancer: the IF protein vimentin, for instance, is linked to tumorigenesis, epithelial-to-mesenchymal transition and the metastatic spread of cancer. In this thesis the mechanics of individual vimentin filaments are probed by using an optical trapping setup which is combined with microfluidics and confocal imaging. Optical traps allow for contact-free measurements of individual proteins in pure buffer and by combining them with microfluidics, the protein environment can be
varied easily while simultaneously observing changes in the mechanics. To be able to compare the results of single filament mechanics to network mechanics, we measure vimentin networks at different conditions with passive microrheology. This method allows us to obtain mechanical properties of networks by tracking micrometer-sized particles embedded in the network. From these particle tracks the mean-squared displacement can be calculated and thereby the viscoelastic response of the network can be derived.2021-09-2
Chapter 10: Certified forest products markets, 2011-2012
This chapter reviews the market and trade in certified forest products (CFPs) and focuses on how market tools such as certification contribute to identifying and procuring sustainable wood products. It also examines policy-related aspects of certification
Spatial Harmonizing of Protected Areas and Renewable Energy Production
Climate change mitigation requires transboundary strategies for the expansion of renewable energies (RE) that are compatible with conservation objectives. The diversity of protected areas (PAs) gives room for integration of a sustainable RE development with nature conservation, but the lack of consistency between PAs designations remains a challenge for transboundary planning.
We propose a methodology to harmonize compatibility assumptions between PA and RE potential production. The methodology is based on the International Union for Conservation of Nature’s (IUCN) System of Protected Areas in order to be independent from national and regional PA designations. Our approach is based on protection scenarios in order to address the multiple uncertainties regarding compatibility assumptions. Three scenarios were defined as: reduced, medium, and increased protection levels.
The three scenarios assigned different compatibility levels for RE potentials to the different PA classes, varying from no restrictions for RE to total incompatibility. The methodology was tested in the Alpine region for four different RE technologies: bioenergy, wind power, solar PV plants, and hydropower. A spatial analysis was carried out using GIS and the sustainable as well as the economic potential for each RE technology were determined using a techno-economic engineering model for RE systems (BeWhere) developed at IIASA.
The results showed considerable trade-offs between nature protection and the potential for RE production, with significant differences depending on the scenario assumptions. Available area and potential for RE production was notably reduced when higher restrictions were assumed (lower compatibility levels, additional buffer with restrictions to protect the strictest PAs, and exclusion of Natura 2000 sites). This study evidences the importance of clear definition of PA management objectives for strategic planning of sustainable RE expansion
Renewable Energy Production from Municipal Solid Waste to Mitigate Climate Change: A Spatially Explicit Assessment for Malaysia
The utilization of municipal solid waste (MSW) as a renewable resource could overcome waste disposal issues, generate power for fossil fuel displacement, and mitigate CO2 emissions from landfill. However, the availability of waste feedstock varies with the effectiveness of waste management while the profitability and the environmental impact are mostly dependent on the conversion technology, plant location, and plant capacity. This study aims to evaluate the complexity of waste-to-energy (WTE) supply chain networks for energy production and the CO2 mitigation potential through a spatially explicit approach. The Malaysian peninsular is selected as a case study area.
This study adapted the IIASA techno-economic engineering model for optimizing renewable energy systems (BeWhere) and developed a WTE optimization component. The model minimizes the full supply chain cost of WTE, optimizes the capacity and location of WTE production plants, and assesses the energy and by-product potentials. Several scenarios were designed to analyze the impact of energy and carbon mitigation potential of WTE with varying the fossil fuel prices or carbon tax in the supply chain.
The results show that incineration and hydrothermal for power production are the preferred options, primarily because of the low economic investment and the high energy conversion efficiency. Apart from the power as the main product, the system produces biofuel as by-product. It is found that most of the plants are installed in more highly populated cities with large potential for waste biomass, hence reducing logistical costs and emissions from transportation. The preliminary results show that WTE could be substituted for about 9% of the Malaysian power production following a business-as-usual scenario.
The study proved that BeWhere for MSW provides a robust spatial explicit solution for WTE with assessment of the energy production and CO2 mitigation potential
Power-to-gas and Power-to-liquids for Managing Renewable Electricity Intermittency in the Alpine Region
Large-scale deployment of renewable energy sources (RES) can play a central role in reducing CO2 emissions from energy supply systems, but intermittency from solar and wind technologies present grid integration challenges. High temperature co-electrolysis of steam and CO2, in the so-called power-to-gas (PtG) and power-to-liquid (PtL) configuration, could provide a path for utilizing the excess intermittent electricity from a power system by converting it into chemical fuels that can be directly utilized in other sectors, such as transportation and heating. The chemical fuels could also be used in the power sector during periods of deficit in supply.
Here, we study the economic and engineering potential of PtG/PtL systems deployment as storage for intermittent renewable electricity and as a source of low-carbon heating and transportation energy among the different energy sectors in the Alpine region, using the BeWhere model, a geographic explicit cost minimization model.
Preliminary results indicate large-scale deployment of the PtG/PtL technologies for producing chemical fuels from excess intermittent electricity is feasible, particularly when incentivized by carbon prices. In addition, large volumes of captured CO2, as much as 30 Mt CO2 /year are utilized in the synthesis of the chemical fuels, providing as much as 23% of liquid transportation fuels. In this context, it can be concluded that PtG/PtL technologies can enable greater integration of RES into the energy supply chain, with application worldwide
Understanding Carbon Cycling of Terrestrial Ecosystems as a Fuzzy System
We outline a methodology of full and verified carbon account of terrestrial ecosystems (FCA) that supposes unbiased assessment of relevant proxy values (here: Net Ecosystem Carbon Budget) and reliable estimation of uncertainties. The FCA is a fuzzy (underspecified) system, of which membership function is inherently stochastic. Thus, any individually used method of FCA is not able to estimate structural uncertainties, that is why usually reported “within method” uncertainties are inevitably partial. Attempting at estimation of “full uncertainties” of the studied system we combine the major methods of terrestrial ecosystems carbon account (landscape-ecosystem method, LEA; process-based models; eddy covariance; and inverse modeling). Assessment of the uncertainties of FCA is provided within each method. Landscape-ecosystem approach (LEA) presents the empirical basis of the FCA in form of an Integrated Land Information System; serves for strict systems designing the account; contains all relevant empirical and semi-empirical data and models. By-pixel parametrization of land cover is provided by utilizing multi-sensor remote sensing data within Geo-Wiki platform and other relevant information based on special optimization algorithms. Major carbon fluxes within the LEA (NPP, HR, disturbances, etc.) are estimated based on fusion of empirical data with process-based elements by sets of regionally distributed models. “Within method” results and uncertainties of the methods examined are harmonized and mutually constrained based on the Bayesian approach. The above methodology have been applied to carbon account of Russian forests for 2000-2010; uncertainties of the FCA for individual years were estimated in limits of ±25%, CI 0.9. We discussed strengths and weaknesses of the approach; system requirements to different methods of the FCA, information and research needs; unresolved problems of cognition of fuzzy system; and obtained and potential levels of uncertainties
Adaptation and mitigation strategies in Northern Eurasian boreal forests
Boreal forests of Northern Eurasia are experiencing ongoing changes in climate, strong impacts by humans including transformation of previously untouched landscapes, and dramatically accelerating disturbance regimes. Current global and regional climatic models predict for this region the most dramatic climatic change over the globe. Unregulated and often destructive anthropogenic impacts on the environment and natural landscapes may substantially accelerate the negative consequences of climatic change. Complexities of the situation are evident: need to take decisions for underspecified dynamics systems under uncertainties; relevancy to consider dual strategy that integrates mitigative and adaptive measures, particularly under no-regret and win-win considerations; necessity to derive minimum mitigation standards from the limits of adaptation; inevitability of non-linear responses and feedbacks and probability to meet surprises in the biosphere's behavior; etc. It defines a need for development of new philosophy of cognition and policy making by using open, iterative, distributed-modular systems based on shared pools of models, tools libraries, and data sets.
Such a situation defines an obligatory need to comprehensively use methodologies of applied system analysis and integrated modeling. Following the basic steps of applied systems analysis (fixation of the problem; diagnostics; (list of) stakeholders; problem mess; setting the goal; criteria; experimental research; analysis of input information; selection of the strategy, development and improvement of the model; depiction of alternatives; and decision making implementation) put the modeling on a solid scientific basis. Integrated models that include components of different nature (ecological, economic, social) are considered as a major tool of perception of future trajectories of forests in a changing world in spite of the fact that application of integrated modeling generates many cognitive problems, trade-offs and challenges.
A central point of adaptation and mitigation strategies is development of robust policies. Robust policies should (1) ensure long-term stability of systems. behavior against multiple events (scenarios); (2) account for extreme events that require specific models; (3) consider uncertainties in a possible comprehensive and explicit form; (4) allow for flexibility to form a diversity of decisions dependent on associated risks and costs, performance indicators of stakeholders, (5) consider in an explicit spatio-temporal way ecological, economic and social dimensions, (6) collective risk; (7) include safety criteria, constraints, and performance indicators of involved agents.
Adaptation and mitigation measures in the forest sector could be effective if they are part of a wide strategy which would involve all relevant sectors of national economy, particularly energy, industry, agriculture, tourism etc. combined in common political and institutional frameworks. Adaptation and anticipatory strategy should be an inherent part of transition to sustainable forest management. However, background philosophy of classical forestry becomes less and less reliable in a continuously changing world. Thus, modeling becomes a working tool for practical adaptive forest management. Adaptive forest management is defined as a management approach that acknowledges the lack of unequivocal and definite knowledge about the ways in which forest ecosystems work, and the uncertainty that dominates interactions with them.
We consider major requirements to and specifics of adaptation and mitigation strategies in boreal forests which include inter alia: (1) a concept of sustainable development and sustainable forest management of regions of high latitudes; (2) integrated land observing systems; (3) a new system of specially protected territories; (4) new strategy and institutional background of forest fire protection; (5) legislative and normative base of adaptation and mitigation as a background of adaptive forest management; (6) system of adaptation of structure of boreal landscapes to climate change; and (7) considering management of major biogeochemical cycles, primarily carbon cycle, as a crucial issue of future strategies. We illustrate some practical results obtained by IIASA-ESM Integrated Modeling Cluster and other approaches. These examples show that recommended strategies could result in higher stability and productivity of forest ecosystems, increased abundance of favored species and reduced fragmentation of forests. However, the biggest problem deals with difficulties to reduce losses from worsening the environment and disturbances. No single strategy appears able to achieve all possible forest management objectives, and adaptation and mitigation strategies should be connected to regional climatic, ecological and social peculiarities
Internalizing the external costs of biogas supply chains in the Italian energy sector
In Italy biogas support schemes are being revised to include subsidies for the production of biomethane. Energy policies should foster environmentally optimal solutions, especially because social acceptance issues often arise in the case of biogas. In this paper we use the external cost methodology to quantify the environmental impact of airborne emissions associated with biogas-based energy vectors and their corresponding fossil substitutes These are evaluated at supply chain level and incorporated in a spatially explicit optimization model. The method is applied to northern Italy to compare the potential impact of alternative policy options. It is found that, while the external costs of biogas-based pathways are always lower than corresponding fossil fuel based pathways, the differences are generally so small that policies based on internalization of external costs alone would not lead to further development of biogas-based technologies. For all utilization pathways, consideration of local externalities leads to a less favourable evaluation of biogas-based technologies, which results in external costs even higher than the substituted fossil fuel if biogas is allocated to local heating
Novel glass-based membranes for Cu adsorption: From alkali activation to sintering
A porous membrane was developed through alkali activation of pharmaceutical boro-aluminosilicate glass powders suspended in diluted NaOH and KOH aqueous solutions (2.5 M). A consolidated porous structure was obtained by the binding of unreacted particles mediated by a surface gel, developed upon drying of the suspensions and their curing at 40 degrees C for 14 days. The binding phase was sufficiently stable to resist immersion in boiling water and in acidic solutions. Copper adsorption tests were carried out under acidic pH, immersing the membranes in a Cu (NO3)2 solution for different periods of time. To determine the effect of surface washing on capture of copper ions, adsorption experiments with washed and unwashed membranes were also carried out, at varying pH. It was determined that the adsorption kinetics follow the pseudosecond-order kinetic model. The main adsorption mechanism observed is the electrostatic interaction between the negative surface charge of the washed membrane and the Cu2+ ions present in solution. An adsorption higher than 60% was observed at pH = 5, while at pH = 2 the efficiency decreased due to the presence of H3O+ ions. To ensure immobilization of copper, the membranes were densified by viscous flow sintering at a moderate temperature (700 degrees C). Leaching tests on membranes demonstrated the efficiency of the process in terms of copper ions immobilization
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