Carbon capture and storage update Boot-Handford, Matthew E; Abanades, Juan C; Anthony, Edward J ...
Energy & environmental science,
01/2014, Letnik:
7, Številka:
1
Journal Article
Recenzirano
In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO
...2
from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO
2
capture technologies, available in the short and long term, and their technological maturity, before discussing CO
2
transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO
2
from the air and CO
2
reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.
A comprehensive discussion of CCS technologies, deployment and prospects across the world.
Piezo1 is a mechanosensitive cation channel with widespread physiological importance; however, its role in the heart is poorly understood. Cardiac fibroblasts help preserve myocardial integrity and ...play a key role in regulating its repair and remodeling following stress or injury. Here we investigated Piezo1 expression and function in cultured human and mouse cardiac fibroblasts. RT-PCR experiments confirmed that Piezo1 mRNA in cardiac fibroblasts is expressed at levels similar to those in endothelial cells. The results of a Fura-2 intracellular Ca2+ assay validated Piezo1 as a functional ion channel that is activated by its agonist, Yoda1. Yoda1-induced Ca2+ entry was inhibited by Piezo1 blockers (gadolinium and ruthenium red) and was reduced proportionally by siRNA-mediated Piezo1 knockdown or in murine Piezo1+/− cells. Results from cell-attached patch clamp recordings on human cardiac fibroblasts established that they contain mechanically activated ion channels and that their pressure responses are reduced by Piezo1 knockdown. Investigation of Yoda1 effects on selected remodeling genes indicated that Piezo1 activation increases both mRNA levels and protein secretion of IL-6, a pro-hypertrophic and profibrotic cytokine, in a Piezo1-dependent manner. Moreover, Piezo1 knockdown reduced basal IL-6 expression from cells cultured on softer collagen-coated substrates. Multiplex kinase activity profiling combined with kinase inhibitor experiments and phosphospecific immunoblotting established that Piezo1 activation stimulates IL-6 secretion via the p38 mitogen-activated protein kinase downstream of Ca2+ entry. In summary, cardiac fibroblasts express mechanically activated Piezo1 channels coupled to secretion of the paracrine signaling molecule IL-6. Piezo1 may therefore be important in regulating cardiac remodeling.
The accurate determination of the solubilities of the typical impurity gases present in captured CO2 in the carbon capture, utilization, and storage chain is an essential prerequisite for the ...successful modeling of the CO2 stream thermodynamic properties. In this paper, Henry’s law constants and the vapor–liquid distribution coefficients of six noncondensable gases, namely, N2, O2, H2, CH4, Ar, and CO, at infinite dilution in liquid CO2 are derived based on published vapor–liquid equilibrium data at temperatures ranging from the triple point (216.59 K) to the critical point (304.13 K) of CO2. The temperature dependence of Henry’s law constants of the six gases is correlated using approximating functions previously proposed for aqueous solutions. A correlation that provides the best fit for the Henry constants data for all the six gases, with the accuracy (absolute average deviation %) of 4.2%, is recommended. For N2, O2, H2, Ar, and CO, the combined standard uncertainty in the derived Henry constants is less than 6%, whereas for CH4, due to a larger deviation between the utilized data, the uncertainty is less than 18%. Analysis of the temperature variation of the vapor–liquid distribution coefficient at infinite dilution shows that when all the six gases are present in the CO2 stream, separation of N2, O2, Ar, and CO from CO2 can be problematic due to their similar volatilities, while the distinct volatilities of H2 and CH4 at lower temperatures make their separation from CO2 easier.
Shale gas could help address the insatiable global demand for energy. However, in addition to risks of environmental pollution, the risk of induced seismicity during the hydraulic fracturing process ...is often considered as the major showstopper in the public acceptability of shale gas as an alternative source of fossil fuel. Other types of subsurface energy development have also demonstrated similar induced seismicity risks. This article presents an interdisciplinary review of notable cases of suspected induced seismicity relating to subsurface energy operations, covering operations for hydraulic fracturing, wastewater injection, conventional gas extraction, enhanced geothermal systems and water impoundment. Possible causal mechanisms of induced seismicity are described and illustrated, then methods to mitigate induced seismicity, encompassing regulations, including so‐called traffic light systems, monitoring and assessment, and numerical modeling approaches for predicting the occurrence of induced seismicity are outlined. Issues relating to public perception of energy technologies in regards to induced seismicity potential are also discussed.
This article is categorized under:
Photovoltaics > Climate and Environment
Fossil Fuels > Climate and Environment
Energy Infrastructure > Economics and Policy
Energy and Development > Systems and Infrastructure
A mechanism for seismicity induced by fluid injection operations is pore pressure increase via a diffusional process (left). This leads to a reduction in the effective normal stress on preexisting faults; allowing frictional resistance to fault sliding to be overcome. This mechanism requires a high permeable pathway from the fluid injection point to the preexisting fault. Even in the circumstances when injection fluids may be hydraulically isolated from any preexisting faults, the fault may be activated through perturbations in the stress field brought about by changes in volume or mass loading transmitted to the fault poroelastically (right: hydraulic fracturing example).
At excitatory synapses, the postsynaptic scaffolding protein postsynaptic density 95 (PSD-95) couples NMDA receptors (NMDARs) to the Ras GTPase-activating protein SynGAP. The close association of ...SynGAP and NMDARs suggests that SynGAP may have an important role in NMDAR-dependent activation of Ras signaling pathways, such as the MAP kinase pathway, and in synaptic plasticity. To explore this issue, we examined long-term potentiation (LTP), p42 MAPK (ERK2) signaling, and spatial learning in mice with a heterozygous null mutation of the SynGAP gene (SynGAP(-/+)). In SynGAP(-/+) mutant mice, the induction of LTP in the hippocampal CA1 region was strongly reduced in the absence of any detectable alteration in basal synaptic transmission and NMDAR-mediated synaptic currents. Although basal levels of activated ERK2 were elevated in hippocampal extracts from SynGAP(-/+) mice, NMDAR stimulation still induced a robust increase in ERK activation in slices from SynGAP(-/+) mice. Thus, although SynGAP may regulate the ERK pathway, its role in LTP most likely involves additional downstream targets. Consistent with this, the amount of potentiation induced by stimulation protocols that induce an ERK-independent form of LTP were also significantly reduced in slices from SynGAP(-/+) mice. An elevation of basal phospho-ERK2 levels and LTP deficits were also observed in SynGAP(-/+)/H-Ras(-)/- double mutants, suggesting that SynGAP may normally regulate Ras isoforms other than H-Ras. A comparison of SynGAP and PSD-95 mutants suggests that PSD-95 couples NMDARs to multiple downstream signaling pathways with very different roles in LTP and learning.
It is often claimed that we do not understand the forces driving the global diversity gradient. However, an extensive literature suggests that contemporary climate constrains terrestrial taxonomic ...richness over broad geographic extents. Here, we review the empirical literature to examine the nature and form of the relationship between climate and richness. Our goals were to document the support for the climatically based energy hypothesis, and within the constraints imposed by correlative analyses, to evaluate two versions of the hypothesis: the productivity and ambient energy hypotheses. Focusing on studies extending over 800 km, we found that measures of energy, water, or water-energy balance explain spatial variation in richness better than other climatic and non-climatic variables in 82 of 85 cases. Even when considered individually and in isolation, water/energy variables explain on average over 60% of the variation in the richness of a wide range of plant and animal groups. Further, water variables usually represent the strongest predictors in the tropics, subtropics, and warm temperate zones, whereas energy variables (for animals) or water-energy variables (for plants) dominate in high latitudes. We conclude that the interaction between water and energy, either directly or indirectly (via plant productivity), provides a strong explanation for globally extensive plant and animal diversity gradients, but for animals there also is a latitudinal shift in the relative importance of ambient energy vs. water moving from the poles to the equator. Although contemporary climate is not the only factor influencing species richness and may not explain the diversity pattern for all taxonomic groups, it is clear that understanding water-energy dynamics is critical to future biodiversity research. Analyses that do not include water-energy variables are missing a key component for explaining broad-scale patterns of diversity.
Prognostic indicators in venous ulcers Phillips, Tania J.; Machado, Fidelis; Trout, Richard ...
Journal of the American Academy of Dermatology,
10/2000, Letnik:
43, Številka:
4
Journal Article
Recenzirano
Background: Venous ulcers can be difficult to heal, and prognostic factors for healing have not been fully elucidated. Objective: The objective of this study was to analyze the results of a large ...multicenter venous ulcer trial to retrospectively establish prognostic factors for venous ulcer healing. Methods: This study examined data from a previously published prospective randomized placebo-controlled trial of an oral medication versus placebo treatment for venous ulcers. Local leg ulcer care involved the use of a moisture-retentive dressing and sustained graduated compression with a paste bandage and a self-adherent wrap. The oral medication or placebo was administered on a daily basis with the same dressings and bandage system in both groups for 12 weeks. A total of 165 patients completed the full 12-week treatment period; 83 received ifetroban, 82 received placebo. Results: There was no statistically significant difference in outcome between the two groups. The study showed that consistent local ulcer treatment with a clearly defined system of care was associated with an unexpectedly high percentage (55%) of long-standing large venous ulcers (mean duration, 27 months; mean area, 15.9 cm2) being healed in both groups. Baseline ulcer area and duration of leg ulcer were found to be important in predicting outcome. Ulcers of short duration were found to be most likely to heal. Percent healing and ulcer area at week 3 were good predictors of 100% healing. Ulcers that had at least 40% healing by week 3 predicted more than 70% of the outcomes correctly. Conclusion: From this large study it was determined that baseline ulcer area and ulcer duration are significant predictors of 100% healing and time to heal. Percent healing and ulcer area at week 3 are good predictors of complete ulcer healing. Ulcers that are large, long-standing, and slow to heal after 3 weeks of optimal therapy are unlikely to heal rapidly, and might benefit from alternative therapies. (J Am Acad Dermatol 2000;43:627-30.)
The cholinergic system is profoundly impaired in senile dementia of Alzheimer type (SDAT) and replacement therapy produces only modest clinical benefits. The serotonergic system is also impaired and ...may contribute both to cognitive and non-cognitive symptoms in SDAT. To investigate this further we assessed the effects of lowering brain serotonin using the technique of acute tryptophan depletion on cognitive function in patients with SDAT and in age matched control subjects.
Sixteen patients with probable SDAT and 17 healthy elderly subjects received two amino acid drinks in a within subject, double-blind, placebo-controlled, counterbalanced, crossover design. One of the drinks was nutritionally balanced and contained tryptophan (placebo), the other was identical but contained no tryptophan. A battery of detailed neuropsychological tests was performed between 4 and 6 h after the drink. Mood rating scales and other ratings of behavioural and emotional symptoms were also performed on both occasions.
Acute tryptophan depletion resulted in impairment on tasks of working memory in both groups. There was no group specific effect. Female SDAT subjects performed better on a task of pattern recognition during acute tryptophan depletion compared with placebo. There were no changes in behavioural symptoms during acute tryptophan depletion in either group.
Compromised serotonergic function may be an important contributor to cognitive decline in SDAT and in ageing. Strategies targeting specific 5HT receptors may be helpful in SDAT.
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