Shifting from constant-voltage to constant-current in Parkinson's disease patients with chronic stimulation.

Science.gov (United States)

Amami, P; Mascia, M M; Franzini, A; Saba, F; Albanese, A

2017-08-01

The study aimed to evaluate safety and efficacy of shifting stimulation settings from constant-voltage (CV) to constant-current (CC) programming in patients with Parkinson's disease (PD) and chronic subthalamic nucleus deep brain stimulation (STN DBS). Twenty PD patients with chronic STN DBS set in CV programming were shifted to CC and followed for 3 months; the other stimulation settings and the medication regimen remained unchanged. Side effects, motor, non-motor, executive functions, and impedance were assessed at baseline and during follow-up. No adverse events were observed at time of shifting or during CC stimulation. Motor and non-motor measures remained unchanged at follow-up despite impedance decreased. Compared to baseline, inhibition processes improved at follow-up. The shifting strategy was well tolerated and the clinical outcome was maintained with no need to adjust stimulation settings or medications notwithstanding a decrease of impedance. Improvement of inhibition processes is a finding which needed further investigation.

stimulated BV2 Microglial

African Journals Online (AJOL)

2012-03-26

Mar 26, 2012 ... 2), in LPS-stimulated BV2 microglial cells. The level of NO production was analyzed using Griess reaction. The release of PGE2 was determined using sandwich enzyme-linked immunosorbent assay. The DNA-binding activity of nuclear factor-κB (NF-κB) was measured by electrophoretic mobility shift assay ...

Applying a Dynamic Stomatal Optimization to Predict Shifts in the Functional Composition of Tropical Forests Under Increased Drought And CO2

Science.gov (United States)

Bartlett, M. K.; Detto, M.; Pacala, S. W.

2017-12-01

The accurate prediction of tropical forest carbon fluxes is key to forecasting global climate, but forest responses to projected increases in CO2 and drought are highly uncertain. Here we present a dynamic optimization that derives the trajectory of stomatal conductance (gs) during drought, a key source of model uncertainty, from plant and soil water relations and the carbon economy of the plant hydraulic system. This optimization scheme is novel in two ways. First, by accounting for the ability of capacitance (i.e., the release of water from plant storage tissue; C) to buffer evaporative water loss and maintain gs during drought, this optimization captures both drought tolerant and avoidant hydraulic strategies. Second, by determining the optimal trajectory of plant and soil water potentials, this optimization quantifies species' impacts on the water available to competing plants. These advances allowed us to apply this optimization across the range of physiology trait values observed in tropical species to evaluate shifts in the competitively optimal trait values, or evolutionarily stable hydraulic strategy (ESS), under increased drought and CO2. Increasing the length of the dry season shifted the ESS towards more drought tolerant, rather than avoidant, trait values, and these shifts were larger for longer individual drought periods (i.e., more consecutive days without rainfall), even if the total time spent in drought was the same. Concurrently doubling the CO2 level reduced the magnitude of these shifts and slightly favored drought avoidant strategies under wet conditions. Overall, these analyses predicted that short, frequent droughts would allow elevated CO2 to shift the functional composition in tropical forests towards more drought avoidant species, while infrequent but long drought periods would shift the ESS to more drought tolerant trait values, despite increased CO2. Overall, these analyses quantified the impact of physiology traits on plant performance

Soil [N] modulates soil C cycling in CO2-fumigated tree stands

DEFF Research Database (Denmark)

Dieleman, W. I. J.; Luyssaert, S.; Rey, A.

2010-01-01

Under elevated atmospheric CO2 concentrations, soil carbon (C) inputs are typically enhanced, suggesting larger soil C sequestration potential. However, soil C losses also increase and progressive nitrogen (N) limitation to plant growth may reduce the CO2 effect on soil C inputs with time. We...... compiled a data set from 131 manipulation experiments, and used meta-analysis to test the hypotheses that: (1) elevated atmospheric CO2 stimulates soil C inputs more than C losses, resulting in increasing soil C stocks; and (2) that these responses are modulated by N. Our results confirm that elevated CO2...... induces a C allocation shift towards below-ground biomass compartments. However, the increased soil C inputs were offset by increased heterotrophic respiration (Rh), such that soil C content was not affected by elevated CO2. Soil N concentration strongly interacted with CO2 fumigation: the effect...

Shallow water marine sediment bacterial community shifts along a natural CO2 gradient in the Mediterranean Sea off Vulcano, Italy.

Science.gov (United States)

Kerfahi, Dorsaf; Hall-Spencer, Jason M; Tripathi, Binu M; Milazzo, Marco; Lee, Junghoon; Adams, Jonathan M

2014-05-01

The effects of increasing atmospheric CO(2) on ocean ecosystems are a major environmental concern, as rapid shoaling of the carbonate saturation horizon is exposing vast areas of marine sediments to corrosive waters worldwide. Natural CO(2) gradients off Vulcano, Italy, have revealed profound ecosystem changes along rocky shore habitats as carbonate saturation levels decrease, but no investigations have yet been made of the sedimentary habitat. Here, we sampled the upper 2 cm of volcanic sand in three zones, ambient (median pCO(2) 419 μatm, minimum Ω(arag) 3.77), moderately CO(2)-enriched (median pCO(2) 592 μatm, minimum Ω(arag) 2.96), and highly CO(2)-enriched (median pCO(2) 1611 μatm, minimum Ω(arag) 0.35). We tested the hypothesis that increasing levels of seawater pCO(2) would cause significant shifts in sediment bacterial community composition, as shown recently in epilithic biofilms at the study site. In this study, 454 pyrosequencing of the V1 to V3 region of the 16S rRNA gene revealed a shift in community composition with increasing pCO(2). The relative abundances of most of the dominant genera were unaffected by the pCO(2) gradient, although there were significant differences for some 5 % of the genera present (viz. Georgenia, Lutibacter, Photobacterium, Acinetobacter, and Paenibacillus), and Shannon Diversity was greatest in sediments subject to long-term acidification (>100 years). Overall, this supports the view that globally increased ocean pCO(2) will be associated with changes in sediment bacterial community composition but that most of these organisms are resilient. However, further work is required to assess whether these results apply to other types of coastal sediments and whether the changes in relative abundance of bacterial taxa that we observed can significantly alter the biogeochemical functions of marine sediments.

Divergent Responses of Forest Soil Microbial Communities under Elevated CO2 in Different Depths of Upper Soil Layers.

Science.gov (United States)

Yu, Hao; He, Zhili; Wang, Aijie; Xie, Jianping; Wu, Liyou; Van Nostrand, Joy D; Jin, Decai; Shao, Zhimin; Schadt, Christopher W; Zhou, Jizhong; Deng, Ye

2018-01-01

Numerous studies have shown that the continuous increase of atmosphere CO 2 concentrations may have profound effects on the forest ecosystem and its functions. However, little is known about the response of belowground soil microbial communities under elevated atmospheric CO 2 (eCO 2 ) at different soil depth profiles in forest ecosystems. Here, we examined soil microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) after a 10-year eCO 2 exposure using a high-throughput functional gene microarray (GeoChip). The results showed that eCO 2 significantly shifted the compositions, including phylogenetic and functional gene structures, of soil microbial communities at both soil depths. Key functional genes, including those involved in carbon degradation and fixation, methane metabolism, denitrification, ammonification, and nitrogen fixation, were stimulated under eCO 2 at both soil depths, although the stimulation effect of eCO 2 on these functional markers was greater at the soil depth of 0 to 5 cm than of 5 to 15 cm. Moreover, a canonical correspondence analysis suggested that NO 3 -N, total nitrogen (TN), total carbon (TC), and leaf litter were significantly correlated with the composition of the whole microbial community. This study revealed a positive feedback of eCO 2 in forest soil microbial communities, which may provide new insight for a further understanding of forest ecosystem responses to global CO 2 increases. IMPORTANCE The concentration of atmospheric carbon dioxide (CO 2 ) has continuously been increasing since the industrial revolution. Understanding the response of soil microbial communities to elevated atmospheric CO 2 (eCO 2 ) is important for predicting the contribution of the forest ecosystem to global atmospheric change. This study analyzed the effect of eCO 2 on microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) in a forest ecosystem. Our findings suggest that the compositional and functional structures of microbial

Hidden shift of the ionome of plants exposed to elevated CO2 depletes minerals at the base of human nutrition

Science.gov (United States)

Loladze, Irakli

2014-01-01

Mineral malnutrition stemming from undiversified plant-based diets is a top global challenge. In C3 plants (e.g., rice, wheat), elevated concentrations of atmospheric carbon dioxide (eCO2) reduce protein and nitrogen concentrations, and can increase the total non-structural carbohydrates (TNC; mainly starch, sugars). However, contradictory findings have obscured the effect of eCO2 on the ionome—the mineral and trace-element composition—of plants. Consequently, CO2-induced shifts in plant quality have been ignored in the estimation of the impact of global change on humans. This study shows that eCO2 reduces the overall mineral concentrations (−8%, 95% confidence interval: −9.1 to −6.9, p carbon:minerals in C3 plants. The meta-analysis of 7761 observations, including 2264 observations at state of the art FACE centers, covers 130 species/cultivars. The attained statistical power reveals that the shift is systemic and global. Its potential to exacerbate the prevalence of ‘hidden hunger’ and obesity is discussed. DOI: http://dx.doi.org/10.7554/eLife.02245.001 PMID:24867639

DOES SOIL CO2 EFFLUX ACCLIMATIZETO ELEVATED TEMPERATURE AND CO2 DURING LONG-TERM TREATMENT OF DOUGLAS-FIR SEEDLINGS?

Science.gov (United States)

We investigated the effects of elevated soil temperature and atmospheric CO2 efflux (SCE) during the third an fourth years of study. We hypothesized that elevated temperature would stimulate SCE, and elevated CO2 would also stimulate SCE with the stimulation being greater at hig...

Elevated Atmospheric CO2 and Warming Stimulates Growth and Nitrogen Fixation in a Common Forest Floor Cyanobacterium under Axenic Conditions

Directory of Open Access Journals (Sweden)

Zoë Lindo

2017-03-01

Full Text Available The predominant input of available nitrogen (N in boreal forest ecosystems originates from moss-associated cyanobacteria, which fix unavailable atmospheric N2, contribute to the soil N pool, and thereby support forest productivity. Alongside climate warming, increases in atmospheric CO2 concentrations are expected in Canada’s boreal region over the next century, yet little is known about the combined effects of these factors on N fixation by forest floor cyanobacteria. Here we assess changes in N fixation in a common forest floor, moss-associated cyanobacterium, Nostoc punctiforme Hariot, under elevated CO2 conditions over 30 days and warming combined with elevated CO2 over 90 days. We measured rates of growth and changes in the number of specialized N2 fixing heterocyst cells, as well as the overall N fixing activity of the cultures. Elevated CO2 stimulated growth and N fixation overall, but this result was influenced by the growth stage of the cyanobacteria, which in turn was influenced by our temperature treatments. Taken together, climate change factors of warming and elevated CO2 are expected to stimulate N2 fixation by moss-associated cyanobacteria in boreal forest systems.

Water-Gas Shift and CO Methanation Reactions over Ni-CeO2(111) Catalysts

Energy Technology Data Exchange (ETDEWEB)

S Senanayake; J Evans; S Agnoli; L Barrio; T Chen; J Hrbek; J Rodriguez

2011-12-31

X-ray and ultraviolet photoelectron spectroscopies were used to study the interaction of Ni atoms with CeO{sub 2}(111) surfaces. Upon adsorption on CeO{sub 2}(111) at 300 K, nickel remains in a metallic state. Heating to elevated temperatures (500-800 K) leads to partial reduction of the ceria substrate with the formation of Ni{sup 2+} species that exists as NiO and/or Ce{sub 1-x}Ni{sub x}O{sub 2-y}. Interactions of nickel with the oxide substrate significantly reduce the density of occupied Ni 3d states near the Fermi level. The results of core-level photoemission and near-edge X-ray absorption fine structure point to weakly bound CO species on CeO{sub 2}(111) which are clearly distinguishable from the formation of chemisorbed carbonates. In the presence of Ni, a stronger interaction is observed with chemisorption of CO on the admetal. When the Ni is in contact with Ce{sup +3} cations, CO dissociates on the surface at 300 K forming NiC{sub x} compounds that may be involved in the formation of CH{sub 4} at higher temperatures. At medium and large Ni coverages (>0.3 ML), the Ni/CeO{sub 2}(111) surfaces are able to catalyze the production of methane from CO and H{sub 2}, with an activity slightly higher than that of Ni(100) or Ni(111). On the other hand, at small coverages of Ni (<0.3 ML), the Ni/CeO{sub 2}(111) surfaces exhibit a very low activity for CO methanation but are very good catalysts for the water-gas shift reaction.

FIELD TESTING & OPTIMIZATION OF CO2/SAND FRACTURING TECHNOLOGY

Energy Technology Data Exchange (ETDEWEB)

Raymond L. Mazza

2004-11-30

These contract efforts involved the demonstration of a unique liquid free stimulation technology which was, at the beginning of these efforts, in 1993 unavailable in the US. The process had been developed, and patented in Canada in 1981, and held promise for stimulating liquid sensitive reservoirs in the US. The technology differs from that conventionally used in that liquid carbon dioxide (CO{sub 2}), instead of water is the base fluid. The CO{sub 2} is pumped as a liquid and then vaporizes at reservoir conditions, and because no other liquids or chemicals are used, a liquid free fracture is created. The process requires a specialized closed system blender to mix the liquid CO{sub 2} with proppant under pressure. These efforts were funded to consist of up to 21 cost-shared stimulation events. Because of the vagaries of CO{sub 2} supplies, service company support and operator interest only 19 stimulation events were performed in Montana, New Mexico, and Texas. Final reports have been prepared for each of the four demonstration groups, and the specifics of those demonstrations are summarized. A summary of the demonstrations of a novel liquid-free stimulation process which was performed in four groups of ''Candidate Wells'' situated in Crockett Co., TX; San Juan Co., NM; Phillips Co., MT; and Blaine Co., MT. The stimulation process which employs CO{sub 2} as the working fluid and the production responses were compared with those from wells treated with conventional stimulation technologies, primarily N{sub 2} foam, excepting those in Blaine Co., MT where the reservoir pressure is too low to clean up spent stimulation liquids. A total of 19 liquid-free CO{sub 2}/sand stimulations were performed in 16 wells and the production improvements were generally uneconomic.

The IgV domain of human B7-2 (CD86) is sufficient to co-stimulate T lymphocytes and induce cytokine secretion.

Science.gov (United States)

Rennert, P; Furlong, K; Jellis, C; Greenfield, E; Freeman, G J; Ueda, Y; Levine, B; June, C H; Gray, G S

1997-06-01

B7-1 (CD80) and B7-2 (CD86) are genetically and structurally related molecules expressed on antigen-presenting cells. Both bind CD28 to co-stimulate T lymphocytes, resulting in proliferation and cytokine production. The extracellular portions of B7-1 and B7-2 which bind to CD28 and CTLA-4 are related to Ig variable (V) and Ig constant (C) domain sequences. Recent reports have described splice variant forms of B7 proteins which occur in vivo and are of unknown function. Here we describe soluble recombinant forms of B7-1 and B7-2 containing either both of the Ig-like extracellular domains or the individual IgV or IgC domains coupled to an Ig Fc tail. Soluble B7-1 and B7-2 bind to CD28 and CTLA-4, and effectively co-stimulate T lymphocytes resulting in their proliferation and the secretion of cytokines. Furthermore, the IgV domain of B7-2 binds CD28 and CTLA-4, competes with B7-1 and B7-2 for binding to these receptors, and co-stimulates T lymphocytes. Cross-linked soluble B7-2v was the most potent co-stimulatory molecule tested and was active at a concentration approximately 100-fold lower than cross-linked soluble B7-1 or B7-2 proteins. When bound to tosyl-activated beads, B7-2v was capable of sustaining multiple rounds of T cell expansion. These data complement the description of naturally occurring variants to suggest that T cell co-stimulation in vivo may be regulated by soluble or truncated forms of B7 proteins.

Relationship between thyroid stimulating hormone and night shift work.

Science.gov (United States)

Moon, So-Hyun; Lee, Bum-Joon; Kim, Seong-Jin; Kim, Hwan-Cheol

2016-01-01

Night shift work has well-known adverse effects on health. However, few studies have investigated the relationship between thyroid diseases and night shift work. This study aimed to examine night shift workers and their changes in thyroid stimulating hormones (TSH) levels over time. Medical check-up data (2011-2015) were obtained from 967 female workers at a university hospital in Incheon, Korea. Data regarding TSH levels were extracted from the records, and 2015 was used as a reference point to determine night shift work status. The relationships between TSH levels and night shift work in each year were analyzed using the general linear model (GLM). The generalized estimating equation (GEE) was used to evaluate the repeated measurements over the 5-year period. The GEE analysis revealed that from 2011 to 2015, night shift workers had TSH levels that were 0.303 mIU/L higher than the levels of non-night shift workers (95 % CI: 0.087-0.519 mIU/L, p  = 0.006) after adjusting for age and department. When we used TSH levels of 4.5 ≥ mIU/L to identify subclinical hypothyroidism, night shift workers exhibited a 1.399 fold higher risk of subclinical hypothyroidism (95 % CI: 1.050-1.863, p  = 0.022), compared to their non-night shift counterparts. This result of this study suggests that night shift workers may have an increased risk of thyroid diseases, compared to non-night shift workers.

Evaluating the energy and CO2 emissions impacts of shifts in residential water heating in the United States

International Nuclear Information System (INIS)

Sanders, Kelly T.; Webber, Michael E.

2015-01-01

Water heating represented nearly 13% of 2010 residential energy consumption making it an important target for energy conservation efforts. The objective of this work is to identify spatially-resolved strategies for energy conservation, since little analysis has been done to identify how regional characteristics affect the energy consumed for water heating. We present a first-order thermodynamic analysis, utilizing ab initio calculations and regression methods, to quantify primary energy consumption and CO 2 emissions with regional specificity by considering by considering local electricity mixes, heat rates, solar radiation profiles, heating degrees days, and water heating unit sales for 27 regions of the US. Results suggest that shifting from electric towards natural gas or solar water heating offered primary energy and CO 2 emission reductions in most US regions, but these reductions varied considerably according to regional electricity mix and solar resources. We find that regions that would benefit most from technology transitions, are often least likely to switch due to limited economic incentives. Our results suggest that federal energy factor metrics, which ignore upstream losses in power generation, are insufficient in informing consumers about the energy performance of residential end use appliances. - Highlights: • US energy factor ratings for water heaters ignore upstream losses. • Switching from electric storage water heating reduces CO 2 emissions in most US regions. • Regions with greatest potential for CO 2 avoidance are least likely to shift technologies. • Benefits vary significantly according to climate and regional electricity fuel mix

Global Warming Can Negate the Expected CO2 Stimulation in Photosynthesis and Productivity for Soybean Grown in the Midwestern United States1[W][OA

Science.gov (United States)

Ruiz-Vera, Ursula M.; Siebers, Matthew; Gray, Sharon B.; Drag, David W.; Rosenthal, David M.; Kimball, Bruce A.; Ort, Donald R.; Bernacchi, Carl J.

2013-01-01

Extensive evidence shows that increasing carbon dioxide concentration ([CO2]) stimulates, and increasing temperature decreases, both net photosynthetic carbon assimilation (A) and biomass production for C3 plants. However the [CO2]-induced stimulation in A is projected to increase further with warmer temperature. While the influence of increasing temperature and [CO2], independent of each other, on A and biomass production have been widely investigated, the interaction between these two major global changes has not been tested on field-grown crops. Here, the interactive effect of both elevated [CO2] (approximately 585 μmol mol−1) and temperature (+3.5°C) on soybean (Glycine max) A, biomass, and yield were tested over two growing seasons in the Temperature by Free-Air CO2 Enrichment experiment at the Soybean Free Air CO2 Enrichment facility. Measurements of A, stomatal conductance, and intercellular [CO2] were collected along with meteorological, water potential, and growth data. Elevated temperatures caused lower A, which was largely attributed to declines in stomatal conductance and intercellular [CO2] and led in turn to lower yields. Increasing both [CO2] and temperature stimulated A relative to elevated [CO2] alone on only two sampling days during 2009 and on no days in 2011. In 2011, the warmer of the two years, there were no observed increases in yield in the elevated temperature plots regardless of whether [CO2] was elevated. All treatments lowered the harvest index for soybean, although the effect of elevated [CO2] in 2011 was not statistically significant. These results provide a better understanding of the physiological responses of soybean to future climate change conditions and suggest that the potential is limited for elevated [CO2] to mitigate the influence of rising temperatures on photosynthesis, growth, and yields of C3 crops. PMID:23512883

Including dynamic CO2 intensity with demand response

International Nuclear Information System (INIS)

Stoll, Pia; Brandt, Nils; Nordström, Lars

2014-01-01

Hourly demand response tariffs with the intention of reducing or shifting loads during peak demand hours are being intensively discussed among policy-makers, researchers and executives of future electricity systems. Demand response rates have still low customer acceptance, apparently because the consumption habits requires stronger incentive to change than any proposed financial incentive. An hourly CO 2 intensity signal could give customers an extra environmental motivation to shift or reduce loads during peak hours, as it would enable co-optimisation of electricity consumption costs and carbon emissions reductions. In this study, we calculated the hourly dynamic CO 2 signal and applied the calculation to hourly electricity market data in Great Britain, Ontario and Sweden. This provided a novel understanding of the relationships between hourly electricity generation mix composition, electricity price and electricity mix CO 2 intensity. Load shifts from high-price hours resulted in carbon emission reductions for electricity generation mixes where price and CO 2 intensity were positively correlated. The reduction can be further improved if the shift is optimised using both price and CO 2 intensity. The analysis also indicated that an hourly CO 2 intensity signal can help avoid carbon emissions increases for mixes with a negative correlation between electricity price and CO 2 intensity. - Highlights: • We present a formula for calculating hybrid dynamic CO 2 intensity of electricity generation mixes. • We apply the dynamic CO 2 Intensity on hourly electricity market prices and generation units for Great Britain, Ontario and Sweden. • We calculate the spearman correlation between hourly electricity market price and dynamic CO 2 intensity for Great Britain, Ontario and Sweden. • We calculate carbon footprint of shifting 1 kWh load daily from on-peak hours to off-peak hours using the dynamic CO 2 intensity. • We conclude that using dynamic CO 2 intensity for

Soil warming and CO2 enrichment induce biomass shifts in alpine tree line vegetation.

Science.gov (United States)

Dawes, Melissa A; Philipson, Christopher D; Fonti, Patrick; Bebi, Peter; Hättenschwiler, Stephan; Hagedorn, Frank; Rixen, Christian

2015-05-01

Responses of alpine tree line ecosystems to increasing atmospheric CO2 concentrations and global warming are poorly understood. We used an experiment at the Swiss tree line to investigate changes in vegetation biomass after 9 years of free air CO2 enrichment (+200 ppm; 2001-2009) and 6 years of soil warming (+4 °C; 2007-2012). The study contained two key tree line species, Larix decidua and Pinus uncinata, both approximately 40 years old, growing in heath vegetation dominated by dwarf shrubs. In 2012, we harvested and measured biomass of all trees (including root systems), above-ground understorey vegetation and fine roots. Overall, soil warming had clearer effects on plant biomass than CO2 enrichment, and there were no interactive effects between treatments. Total plant biomass increased in warmed plots containing Pinus but not in those with Larix. This response was driven by changes in tree mass (+50%), which contributed an average of 84% (5.7 kg m(-2) ) of total plant mass. Pinus coarse root mass was especially enhanced by warming (+100%), yielding an increased root mass fraction. Elevated CO2 led to an increased relative growth rate of Larix stem basal area but no change in the final biomass of either tree species. Total understorey above-ground mass was not altered by soil warming or elevated CO2 . However, Vaccinium myrtillus mass increased with both treatments, graminoid mass declined with warming, and forb and nonvascular plant (moss and lichen) mass decreased with both treatments. Fine roots showed a substantial reduction under soil warming (-40% for all roots soil depth) but no change with CO2 enrichment. Our findings suggest that enhanced overall productivity and shifts in biomass allocation will occur at the tree line, particularly with global warming. However, individual species and functional groups will respond differently to these environmental changes, with consequences for ecosystem structure and functioning. © 2014 John Wiley & Sons Ltd.

CD28 co-stimulation down regulates Th17 development.

Directory of Open Access Journals (Sweden)

Salim Bouguermouh

Full Text Available Th17 cells are implicated in host defence and autoimmune diseases. CD28/B7 co-stimulation is involved in the induction and progression of autoimmune diseases, but its role in controlling murine Th17 cell fate remains to be clarified. We here report that soluble anti-CD28 mAb suppressed the differentiation of anti-CD3-stimulated naïve CD4(+ T cells into IL-17-producing cells. CD28 co-stimulation reduced the frequency of proliferating cells that produce IL-17. We provide evidence for an IL-2 and IFN-gamma-dependent mechanism of CD28-mediated IL-17 suppression. CD28 blockade of Th17 development was correlated with a decrease rather than an increase in the percentage of Foxp3(+ T cells. In APC/T cell co-cultures, mature dendritic cells (DC were less efficient than immature DC in their ability to support Th17 cell differentiation, while CTLA4-Ig, an agent blocking CD28/B7 and CTLA4/B7 interactions, facilitated both murine and human Th17 differentiation. This study identifies the importance of B7 co-stimulatory molecules in the negative regulation of Th17 development. These unexpected results caution targeting the CD28/B7 pathways in the treatment of human autoimmune diseases.

Field Evidence for Co-Metabolism of Trichloroethene Stimulated by Addition of Electron Donor to Groundwater

Energy Technology Data Exchange (ETDEWEB)

Conrad, Mark E.; Brodie, Eoin L.; Radtke, Corey W.; Bill, Markus; Delwiche, Mark E.; Lee, M. Hope; Swift, Dana L.; Colwell, Frederick S.

2010-05-17

For more than 10 years, electron donor has been injected into the Snake River aquifer beneath the Test Area North site of the Idaho National Laboratory for the purpose of stimulating microbial reductive dechlorination of trichloroethene (TCE) in groundwater. This has resulted in significant TCE removal from the source area of the contaminant plume and elevated dissolved CH4 in the groundwater extending 250 m from the injection well. The delta13C of the CH4 increases from 56o/oo in the source area to -13 o/oo with distance from the injection well, whereas the delta13C of dissolved inorganic carbon decreases from 8 o/oo to -13 o/oo, indicating a shift from methanogenesis to methane oxidation. This change in microbial activity along the plume axis is confirmed by PhyloChip microarray analyses of 16S rRNA genes obtained from groundwater microbial communities, which indicate decreasing abundances of reductive dechlorinating microorganisms (e.g., Dehalococcoides ethenogenes) and increasing CH4-oxidizing microorganisms capable of aerobic co-metabolism of TCE (e.g., Methylosinus trichosporium). Incubation experiments with 13C-labeled TCE introduced into microcosms containing basalt and groundwater from the aquifer confirm that TCE co-metabolism is possible. The results of these studies indicate that electron donor amendment designed to stimulate reductive dechlorination of TCE may also stimulate co-metabolism of TCE.

Stimulated phase-shift acoustic nanodroplets enhance vancomycin efficacy against methicillin-resistant Staphylococcus aureus biofilms

Directory of Open Access Journals (Sweden)

Guo H

2017-06-01

Full Text Available Hao Guo,1 Ziming Wang,1 Quanyin Du,1 Pan Li,2 Zhigang Wang,2 Aimin Wang1 1Department of Orthopedics, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China; 2Chongqing Key Laboratory of Ultrasound Molecular Imaging, Institute of Ultrasound Imaging, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China Purpose: Bacterial biofilms on the surface of prostheses are becoming a rising concern in managing prosthetic joint infections. The inherent resistant features of biofilms render traditional antimicrobial therapy unproductive and revision surgery outcomes uncertain. This situation has prompted the exploration of novel antimicrobial strategies. The synergy of ultrasound microbubbles and vancomycin has been proposed as an efficient alternative for biofilm eradication. The purpose of this study was to evaluate the anti-biofilm effect of stimulated phase-shift acoustic nanodroplets (NDs combined with vancomycin.Materials and methods: We fabricated lipid phase-shift NDs with a core of liquid perfluoropentane. A new phase change mode for NDs incorporating an initial unfocused low-intensity pulsed ultrasound for 5 minutes and a subsequent incubation at 37°C into a 24-hour duration was developed. Methicillin-resistant Staphylococcus aureus (MRSA biofilms were incubated with vancomycin and NDs under the hybrid stimulation. Biofilm morphology following treatment was determined using confocal laser scanning microscopy and scanning electron microscopy. Resazurin assay was used to quantify bactericidal efficacy against MRSA biofilm bacteria.Results: NDs treated sequentially with ultrasound and heating at 37°C achieved gradual and substantial ND vaporization and cavitation in a successive process. NDs after stimulation were capable of generating stronger destruction on biofilm structure which was best characterized by residual circular arc margins and more dead bacteria. Furthermore, NDs

Tidal marsh plant responses to elevated CO2 , nitrogen fertilization, and sea level rise.

Science.gov (United States)

Adam Langley, J; Mozdzer, Thomas J; Shepard, Katherine A; Hagerty, Shannon B; Patrick Megonigal, J

2013-05-01

Elevated CO2 and nitrogen (N) addition directly affect plant productivity and the mechanisms that allow tidal marshes to maintain a constant elevation relative to sea level, but it remains unknown how these global change drivers modify marsh plant response to sea level rise. Here we manipulated factorial combinations of CO2 concentration (two levels), N availability (two levels) and relative sea level (six levels) using in situ mesocosms containing a tidal marsh community composed of a sedge, Schoenoplectus americanus, and a grass, Spartina patens. Our objective is to determine, if elevated CO2 and N alter the growth and persistence of these plants in coastal ecosystems facing rising sea levels. After two growing seasons, we found that N addition enhanced plant growth particularly at sea levels where plants were most stressed by flooding (114% stimulation in the + 10 cm treatment), and N effects were generally larger in combination with elevated CO2 (288% stimulation). N fertilization shifted the optimal productivity of S. patens to a higher sea level, but did not confer S. patens an enhanced ability to tolerate sea level rise. S. americanus responded strongly to N only in the higher sea level treatments that excluded S. patens. Interestingly, addition of N, which has been suggested to accelerate marsh loss, may afford some marsh plants, such as the widespread sedge, S. americanus, the enhanced ability to tolerate inundation. However, if chronic N pollution reduces the availability of propagules of S. americanus or other flood-tolerant species on the landscape scale, this shift in species dominance could render tidal marshes more susceptible to marsh collapse. © 2013 Blackwell Publishing Ltd.

Warm Water Bath Stimulates Phase-Shifts of the Peripheral Circadian Clocks in PER2::LUCIFERASE Mouse

Science.gov (United States)

Kuriki, Daisuke; Haraguchi, Atsushi; Shibata, Shigenobu

2014-01-01

Circadian clocks in the peripheral tissues of mice are known to be entrained by pulse stimuli such as restricted feeding, novel wheel running, and several other agents. However, there are no reports on high temperature pulse-mediated entrainment on the phase-shift of peripheral clocks in vivo. Here we show that temperature treatment of mice for two days at 41°C, instead of 37°C, for 1–2 h during the inactive period, using a temperature controlled water bath stimulated phase-advance of peripheral clocks in the kidney, liver, and submandibular gland of PER2::LUCIFERASE mice. On the other hand, treatment for 2 days at 35°C ambient room temperature for 2 h did not cause a phase-advance. Maintenance of mice at 41°C in a water bath, sustained the core body temperature at 40–41°C. However, the use of 37°C water bath or the 35°C ambient room temperature elevated the core body temperature to 38.5°C, suggesting that at least a core body temperature of 40–41°C is necessary to cause phase-advance under light-dark cycle conditions. The temperature pulse stimulation at 41°C, instead of 37°C water bath for 2 h led to the elevated expression of Per1 and Hsp70 in the peripheral tissue of mice. In summary, the present study demonstrates that transient high temperature pulse using water bath during daytime causes phase-advance in mouse peripheral clocks in vivo. The present results suggest that hot water bath may affect the phase of peripheral clocks. PMID:24933288

trans-(Cl)-[Ru(5,5'-diamide-2,2'-bipyridine)(CO)2 Cl2 ]: Synthesis, Structure, and Photocatalytic CO2 Reduction Activity.

Science.gov (United States)

Kuramochi, Yusuke; Fukaya, Kyohei; Yoshida, Makoto; Ishida, Hitoshi

2015-07-06

A series of trans-(Cl)-[Ru(L)(CO)2 Cl2 ]-type complexes, in which the ligands L are 2,2'-bipyridyl derivatives with amide groups at the 5,5'-positions, are synthesized. The C-connected amide group bound to the bipyridyl ligand through the carbonyl carbon atom is twisted with respect to the bipyridyl plane, whereas the N-connected amide group is in the plane. DFT calculations reveal that the twisted structure of the C-connected amide group raises the level of the LUMO, which results in a negative shift of the first reduction potential (Ep ) of the ruthenium complex. The catalytic abilities for CO2 reduction are evaluated in photoreactions (λ>400 nm) with the ruthenium complexes (the catalyst), [Ru(bpy)3 ](2+) (bpy=2,2'-bipyridine; the photosensitizer), and 1-benzyl-1,4-dihydronicotinamide (the electron donor) in CO2 -saturated N,N-dimethylacetamide/water. The logarithm of the turnover frequency increases by shifting Ep a negative value until it reaches the reduction potential of the photosensitizer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pressure Swing Absorption Device and Process for Separating CO{sub 2} from Shifted Syngas and its Capture for Subsequent Storage

Energy Technology Data Exchange (ETDEWEB)

Sirkar, Kamalesh; Jie, Xingming; Chau, John; Obuskovic, Gordana

2013-03-31

Using the ionic liquid (IL) 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]) as the absorbent on the shell side of a membrane module containing either a porous hydrophobized ceramic tubule or porous hydrophobized polyether ether ketone (PEEK) hollow fiber membranes, studies for CO{sub 2} removal from hot simulated pre-combustion shifted syngas were carried out by a novel pressure swing membrane absorption (PSMAB) process. Helium was used as a surrogate for H{sub 2} in a simulated shifted syngas with CO{sub 2} around 40% (dry gas basis). In this cyclic separation process, the membrane module was used to achieve non-dispersive gas absorption from a high-pressure feed gas (689-1724 kPag; 100-250 psig) at temperatures between 25-1000C into a stationary absorbent liquid on the module shell side during a certain part of the cycle followed by among other cycle steps controlled desorption of the absorbed gases from the liquid in the rest of the cycle. Two product streams were obtained, one He-rich and the other CO{sub 2}-rich. Addition of polyamidoamine (PAMAM) dendrimer of generation 0 to IL [bmim][DCA] improved the system performance at higher temperatures. The solubilities of CO{sub 2} and He were determined in the ionic liquid with or without the dendrimer in solution as well as in the presence or absence of moisture; polyethylene glycol (PEG) 400 was also studied as a replacement for the IL. The solubility selectivity of the ionic liquid containing the dendrimer for CO{sub 2} over helium was considerably larger than that for the pure ionic liquid. The solubility of CO{sub 2} and CO{sub 2}-He solubility selectivity of PEG 400 and a solution of the dendrimer in PEG 400 were higher than the corresponding ones in the IL, [bmim][DCA]. A mathematical model was developed to describe the PSMAB process; a numerical solution of the governing equations described successfully the observed performance of the PSMAB process for the pure ionic liquid-based system.

Exergy analysis of a hydrogen fired combined cycle with natural gas reforming and membrane assisted shift reactors for CO2 capture

International Nuclear Information System (INIS)

Atsonios, K.; Panopoulos, K.D.; Doukelis, A.; Koumanakos, A.; Kakaras, Em.

2012-01-01

Highlights: ► Exergy analysis of NGCC with CCS. ► WGS-MR: exergetically efficient technology for CCS, less than 2% total exergy losses. ► 10% of total exergy dissipation in the ATR. ► Optimization of ATR operation and CO 2 stream treatment. - Abstract: Hydrogen production from fossil fuels together with carbon capture has been suggested as a means of providing a carbon free power. The paper presents a comparative exergetic analysis performed on the hydrogen production from natural gas with several combinations of reactor systems: (a) oxy or air fired autothermal reforming with subsequent water gas shift reactor and (b) membrane reactor assisted with shift catalysts. The influence of reactor temperature and pressure as well as operating parameter steam-to-carbon ratio, is also studied exergetically. The results indicate optimal power plant configurations with CO 2 capture, or hydrogen delivery for industrial applications.

Financial Rewards Do Not Stimulate Co-Production : Evidence from Two Experiments

NARCIS (Netherlands)

W.H. Voorberg (William); S.R. Jilke (Sebastian); L.G. Tummers (Lars); V.J.J.M. Bekkers (Victor)

2017-01-01

textabstractWestern governments are increasingly trying to stimulate citizens to ‘co-produce’ public services, among others, by offering them financial incentives. However, there are competing views on whether financial incentives stimulate co-production. While some argue it increases citizens’

Pharmacological modulation of cortical excitability shifts induced by transcranial direct current stimulation in humans.

Science.gov (United States)

Nitsche, M A; Fricke, K; Henschke, U; Schlitterlau, A; Liebetanz, D; Lang, N; Henning, S; Tergau, F; Paulus, W

2003-11-15

Transcranial direct current stimulation (tDCS) of the human motor cortex results in polarity-specific shifts of cortical excitability during and after stimulation. Anodal tDCS enhances and cathodal stimulation reduces excitability. Animal experiments have demonstrated that the effect of anodal tDCS is caused by neuronal depolarisation, while cathodal tDCS hyperpolarises cortical neurones. However, not much is known about the ion channels and receptors involved in these effects. Thus, the impact of the sodium channel blocker carbamazepine, the calcium channel blocker flunarizine and the NMDA receptor antagonist dextromethorphane on tDCS-elicited motor cortical excitability changes of healthy human subjects were tested. tDCS-protocols inducing excitability alterations (1) only during tDCS and (2) eliciting long-lasting after-effects were applied after drug administration. Carbamazepine selectively eliminated the excitability enhancement induced by anodal stimulation during and after tDCS. Flunarizine resulted in similar changes. Antagonising NMDA receptors did not alter current-generated excitability changes during a short stimulation, which elicits no after-effects, but prevented the induction of long-lasting after-effects independent of their direction. These results suggest that, like in other animals, cortical excitability shifts induced during tDCS in humans also depend on membrane polarisation, thus modulating the conductance of sodium and calcium channels. Moreover, they suggest that the after-effects may be NMDA receptor dependent. Since NMDA receptors are involved in neuroplastic changes, the results suggest a possible application of tDCS in the modulation or induction of these processes in a clinical setting. The selective elimination of tDCS-driven excitability enhancements by carbamazepine proposes a role for this drug in focussing the effects of cathodal tDCS, which may have important future clinical applications.

Surfactant secretion is stimulated by decreased alveolar CO2

International Nuclear Information System (INIS)

Chander, A.; Dodia, C.R.; Gullo, J.; Fisher, A.B.

1986-01-01

The authors investigated the hypothesis that altered intracellular pH may modulate lung surfactant secretion. They have used isolated perfused lung preparation to investigate release of [ 3 H]choline labeled phosphatidylcholine (PC) in the alveolar space of rat lungs ventilated with 5%, 2.5%, or 0% CO 2 in air. Adult rats were injected i.p. 40uCi of [ 3 H-methyl] choline and lungs removed after 45 min. Lungs were perfused for 15 or 60 min. with KRB plus 25 mM HEPES. At the end of perfusion lungs were lavaged five times with 7 ml of ice cold saline. Lavage fluid, was centrifuged, lyophilized, and both lung and lavage fluid extracted for lipids. Lipid choline label in lavage fluid, expressed as percent of that in lung lipids, from control lungs (5% CO 2 ) showed 0.6 +/- 0.1 % at 15 min and 1.1 +/- 0.3% (mean +/- SE, n=6) label at 60 min. When perfused with 50 μM 1-isoproterenol, the label after 60 min perfusion increased to 2.76 +/- 0.33 (n=3). Ventilation with air containing 2.5% CO 2 and 0% CO 2 showed 6.1 +/- 2.1 % (n=4) and 6.4 +/- 1.8% (n=4) label in lavage fluid. Addition of 25mM sodium acetate in the perfusion medium and ventilation with 0% CO 2 in air lowered release of label to 4.2 +/- 1.4% (n=4). These results show that low pCO 2 increases surfactant PC secretion in lung and suggest that intracellular alkalosis triggers surfactant release

Production of hydrogen using the combination of water-gas shift and carbonatation reaction of a CO{sub 2} absorbent; Produccion de hidrogeno mediante la combinacion de las reacciones de desplazamiento de agua y carbonatacion de un absorbente de CO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Escobedo-Bretado, M. A.; Ponce-Pena, P. [Facultad de Ciencias Quimicas, UJED, Durango, Durango (Mexico)]. E-mail: miguel.escobedo@ujed.mx; Delgado-Vigil, M. D.; Salinas-Gutierrez, J. M.; Lopez Ortiz, A.; Collins-Martinez, V.H. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)

2009-09-15

The production of hydrogen by the water-gas shift (WGS) normally requires multiple catalytic reactions followed by the separation of CO{sub 2} to obtain highly pure H{sub 2}. Nevertheless, using the combination of the WGS reaction and the solid-gas reaction between CO{sub 2} and an absorbent, the production of H{sub 2} and the separation of CO{sub 2} can be accomplished in a single step AEWGS (Absorption Enhanced Water Gas Shift). This combination of reactions was studied at the laboratory scale using a quartz fixed-bed reactor. The absorbents tested were calcined dolomite (CaO*MgO) and sodium zirconate (Na{sub 2}ZrO{sub 3}) in catalyst/absorbent mixtures (cat/abs) with weight ratios of 1/1, 1/2 and 2/1, using a high-temperature catalyst from the WGS reaction, synthesized in the laboratory (Fe-Cr). All the tests used 3cm{sup 3} of cat/abs, composed of 5% CO, 15% H{sub 2}O, 10.5% He and 69.5% N{sub 2}, with a spatial velocity (SV) of 1500h-1, 600 degrees Celsius and atmospheric pressure. The catalyst presented 100% conversion of CO to CO{sub 2}, maintaining its surface area after the reaction (12 m{sup 2}/g). The results with a dry base using the cat/abs mixture of 1/2 and CaO*MgO generated 95% H{sub 2} with 5% CO-free CO{sub 2}, while with Na{sub 2}ZrO{sub 3}, the maximum concentration of H{sub 2} was 70%, with 29% CO{sub 2} and 1% of CO without reacting. The results using only CaO*MgO (as a bifunctional material) presented a maximum H{sub 2} concentration of 96% and a minimum of 4% CO{sub 2}, as well as 7% CO without reaction, which was attributed to kinetic effects. [Spanish] La produccion de hidrogeno mediante la reaccion de desplazamiento de agua WGS (Water Gas Shift), normalmente requiere de multiples reacciones cataliticas seguidas por la separacion de CO{sub 2} para obtener H{sub 2} de alta pureza. Sin embargo mediante la combinacion de la reaccion WGS con la reaccion solido-gas entre el CO{sub 2} y un absorbente provee la oportunidad de producir H2 y

Laboratory Experiments to Stimulate CO2 Ocean Disposal

International Nuclear Information System (INIS)

Masutani, S.M.

1997-01-01

This Technical Progress Report summarizes activities conducted over the period 8/16/96-2/15/97 as part of this project. This investigation responds to the possibility that restrictions on greenhouse gas emissions may be imposed in the future to comply with the Framework Convention on Climate Change. The primary objective of the investigation is to obtain experimental data that can be applied to assess the technical feasibility and environmental impacts of oceanic containment strategies to limit release of carbon dioxide (CO 2 ) from coal and other fossil fuel combustion systems into the atmosphere. Critical technical uncertainties of ocean disposal of CO 2 will be addressed by performing experiments that: (1) characterize size spectra and velocities of a dispersed CO 2 phase in the near-field of a discharge jet; and (2) estimate rates of mass transfer from dissolving droplets of liquid CO 2 encased in a thin hydrate shell. Experiments will be conducted in a laboratory facility that can reproduce conditions in the ocean to depths of 600 m (1,969 ft). Between 8/16/96 and 2/15/97, activities focused on modifications to the experimental apparatus and the testing of diagnostics. Following completion of these tasks, experiments will be initiated and will continue through the end of the 36 month period of performance. Major accomplishments of this reporting period were: (1) delivery, set-up, and testing of the PDPA (Phase Doppler Particle Analyzer), which will be the principal diagnostic of the continuous CO 2 jet injection tests; (2) presentation of research papers and posters at the 212th American Chemical Society National Meeting and the Third International Conference on Carbon Dioxide Removal; (3) participation in the 4th Expert Workshop on Ocean Storage of Carbon Dioxide; (4) execution of an Agreement with ABB Management, Ltd. to support and extend the activities of this grant; and (5) initiation of research collaborations with Dr. P.M. Haugen of the University of

Effect of elevated CO2, O3, and UV radiation on soils.

Science.gov (United States)

Formánek, Pavel; Rejšek, Klement; Vranová, Valerie

2014-01-01

In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil N t content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research.

Flavonoids released by carrot (Daucus carota) seedlings stimulate hyphal development of vesicular-arbuscular mycorrhizal fungi in the presence of optimal CO2 enrichment.

Science.gov (United States)

Poulin, M J; Bel-Rhlid, R; Piché, Y; Chênevert, R

1993-10-01

Carbon dioxide has been previously identified as a critical volatile factor that stimulates hyphal growth ofGigaspora margarita, a vesiculararbuscular mycorrhizal fungus, and we determined the optimal concentration at 2.0%. The beneficial effect of CO2 on fungal development is also visible in the presence of stimulatory (quercetin, myricetin) or inhibitory (naringenin) flavonoids. Sterile root exudates from carrot seedlings stimulate the hyphal development ofG. margarita in the presence of optimal CO2 enrichment. Three flavonols (quercetin, kaempferol, rutin or quercetin 3-rutinoside) and two flavones (apigenin, luteolin) were identified in carrot root exudates by means of HPLC retention time. Flavonols like quercetin and kaempferol are known to have stimulatory effects on hyphal growth ofG. margarita.

Stimulated Respiration and Net Photosynthesis in Cassiopeia sp. during Glucose Enrichment Suggests in hospite CO2 Limitation of Algal Endosymbionts

KAUST Repository

Radecker, Nils

2017-08-15

The endosymbiosis between cnidarians and dinoflagellates of the genus Symbiodinium is key to the high productivity of tropical coral reefs. In this endosymbiosis, Symbiodinium translocate most of their photosynthates to their animal host in exchange for inorganic nutrients. Among these, carbon dioxide (CO ) derived fromhost respiration helps to meet the carbon requirements to sustain photosynthesis of the dinoflagellates. Nonetheless, recent studies suggest that productivity in symbiotic cnidarians such as corals is CO -limited. Here we show that glucose enrichment stimulates respiration and gross photosynthesis rates by 80 and 140%, respectively, in the symbiotic upside-down jellyfish Cassiopeia sp. from the Central Red Sea. Our findings show that glucose was rapidly consumed and respired within the Cassiopeia sp. holobiont. The resulting increase of CO availability in hospite in turn likely stimulated photosynthesis in Symbiodinium. Hence, the increase of photosynthesis under these conditions suggests that CO limitation of Symbiodinium is a common feature of stable cnidarian holobionts and that the stimulation of holobiont metabolism may attenuate this CO limitation.

Plants increase laccase activity in soil with long-term elevated CO2 legacy

DEFF Research Database (Denmark)

Partavian, Asrin; Mikkelsen, Teis Nørgaard; Vestergård, Mette

2015-01-01

[CO2] stimulate laccase activity. We incubated soil exposed to seven years of elevated or ambient field [CO2] in ambient or elevated [CO2] chambers for six months either with or without plants (Deschampsia flexuosa). Elevated chamber [CO2] increased D. flexuosa production and belowground respiration....... Interestingly, plants also grew larger in soil with an elevated [CO2] legacy. Plants stimulated soil microbial biomass, belowground respiration and laccase activity, and the plant-induced laccase stimulation was particularly apparent in soil exposed to long-term elevated [CO2] in the field, whereas laccase......Actively growing plants can stimulate mineralization of recalcitrant soil organic matter (SOM), and increased atmospheric [CO2] can further enhance such plant-mediated SOM degradation. Laccases are central for recalcitrant SOM decomposition, and we therefore hypothesized that plants and elevated...

CO2 sensing and CO2 regulation of stomatal conductance: advances and open questions

Science.gov (United States)

Engineer, Cawas; Hashimoto-Sugimoto, Mimi; Negi, Juntaro; Israelsson-Nordstrom, Maria; Azoulay-Shemer, Tamar; Rappel, Wouter-Jan; Iba, Koh; Schroeder, Julian

2015-01-01

Guard cells form epidermal stomatal gas exchange valves in plants and regulate the aperture of stomatal pores in response to changes in the carbon dioxide (CO2) concentration in leaves. Moreover, the development of stomata is repressed by elevated CO2 in diverse plant species. Evidence suggests that plants can sense CO2 concentration changes via guard cells and via mesophyll tissues in mediating stomatal movements. We review new discoveries and open questions on mechanisms mediating CO2-regulated stomatal movements and CO2 modulation of stomatal development, which together function in CO2-regulation of stomatal conductance and gas exchange in plants. Research in this area is timely in light of the necessity of selecting and developing crop cultivars which perform better in a shifting climate. PMID:26482956

The Synergy Effect of Ni-M (M = Mo, Fe, Co, Mn or Cr Bicomponent Catalysts on Partial Methanation Coupling with Water Gas Shift under Low H2/CO Conditions

Directory of Open Access Journals (Sweden)

Xinxin Dong

2017-02-01

Full Text Available Ni-M (M = Mo, Fe, Co, Mn or Cr bicomponent catalysts were prepared through the co-impregnation method for upgrading low H2/CO ratio biomass gas into urban gas through partial methanation coupling with water gas shift (WGS. The catalysts were characterized by N2 isothermal adsorption, X-ray diffraction (XRD, H2 temperature programmed reduction (H2-TPR, H2 temperature programmed desorption (H2-TPD, scanning electron microscopy (SEM and thermogravimetry (TG. The catalytic performances demonstrated that Mn and Cr were superior to the other three elements due to the increased fraction of reducible NiO particles, promoted dispersion of Ni nanoparticles and enhanced H2 chemisorption ability. The comparative study on Mn and Cr showed that Mn was more suitable due to its smaller carbon deposition rate and wider adaptability to various H2/CO and H2O/CO conditions, indicating its better synergy effect with Ni. A nearly 100 h, the lifetime test and start/stop cycle test further implied that 15Ni-3Mn was stable for industrial application.

CO2 hydrogenation to hydrocarbons over iron nanoparticles ...

Indian Academy of Sciences (India)

481–486. c Indian Academy of Sciences. CO2 ... degrees of CO2 conversion shows that reverse water gas shift equilibrium had been ... rise in CO2 emission.1 Additionally, depletion in crude .... detectors (FID) using argon as internal standard.

Field Effect Devices Sensitive to CO at Room Temperature

Directory of Open Access Journals (Sweden)

Ricardo ARAG?N

2014-10-01

Full Text Available [5,10,15-Tris(2,6-dichlorophenylcorrolate] cobalt(III was used to chemisorb CO selectively, on the gap-gate of MOS capacitors and the state of charge monitored by voltage shifts of the photocurrent induced by pulsed illumination under constant D. C. bias, proportionally to CO concentration in air. Negative chemically induced charges at room temperature induce positive responses above and negative shifts below the threshold voltage, conforming to acceptor behavior, and the dynamic range (125 ppm is limited by the silicon doping concentration. The linear proportionality between CO concentration and surface charge (6.46[ppm.m2.µC-1] corresponds to the low concentration limit of the Langmuir isotherm. Sluggish CO desorption can be compensated by photo stimulation at 395 nm.

Effect of Elevated CO2, O3, and UV Radiation on Soils

Directory of Open Access Journals (Sweden)

Pavel Formánek

2014-01-01

Full Text Available In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil Nt content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research.

Effect of Elevated CO2, O3, and UV Radiation on Soils

Science.gov (United States)

Rejšek, Klement; Vranová, Valerie

2014-01-01

In this work, we have attempted to review the current knowledge on the impact of elevated CO2, O3, and UV on soils. Elevated CO2 increases labile and stabile soil C pool as well as efficiency of organic pollutants rhizoremediation and phytoextraction of heavy metals. Conversely, both elevated O3 and UV radiation decrease inputs of assimilates to the rhizosphere being accompanied by inhibitory effects on decomposition processes, rhizoremediation, and heavy metals phytoextraction efficiency. Contrary to elevated CO2, O3, or UV-B decreases soil microbial biomass, metabolisable C, and soil Nt content leading to higher C/N of soil organic matter. Elevated UV-B radiation shifts soil microbial community and decreases populations of soil meso- and macrofauna via direct effect rather than by induced changes of litter quality and root exudation as in case of elevated CO2 or O3. CO2 enrichment or increased UV-B is hypothesised to stimulate or inhibit both plant and microbial competitiveness for soluble soil N, respectively, whereas O3 favours only microbial competitive efficiency. Understanding the consequences of elevated CO2, O3, and UV radiation for soils, especially those related to fertility, phytotoxins inputs, elements cycling, plant-microbe interactions, and decontamination of polluted sites, presents a knowledge gap for future research. PMID:24688424

Transcranial direct current stimulation of the left dorsolateral prefrontal cortex shifts preference of moral judgments.

Directory of Open Access Journals (Sweden)

Maria Kuehne

Full Text Available Attitude to morality, reflecting cultural norms and values, is considered unique to human social behavior. Resulting moral behavior in a social environment is controlled by a widespread neural network including the dorsolateral prefrontal cortex (DLPFC, which plays an important role in decision making. In the present study we investigate the influence of neurophysiological modulation of DLPFC reactivity by means of transcranial direct current stimulation (tDCS on moral reasoning. For that purpose we administered anodal, cathodal, and sham stimulation of the left DLPFC while subjects judged the appropriateness of hard moral personal dilemmas. In contrast to sham and cathodal stimulation, anodal stimulation induced a shift in judgment of personal moral dilemmas towards more non-utilitarian actions. Our results demonstrate that alterations of left DLPFC activity can change moral judgments and, in consequence, provide a causal link between left DLPFC activity and moral reasoning. Most important, the observed shift towards non-utilitarian actions suggests that moral decision making is not a permanent individual trait but can be manipulated; consequently individuals with boundless, uncontrollable, and maladaptive moral behavior, such as found in psychopathy, might benefit from neuromodulation-based approaches.

CO2 Effects in Space: Relationship to Intracranial Hypertension

Science.gov (United States)

Alexander, David J.

2011-01-01

This slide presentation reviews the effects of enhanced exposure to CO2 on Earth and in space. The effects of enhanced exposure to CO2 are experienced in almost all bodily systems. In space some of the effects are heightened due to the fluid shifts to the thorax and head. This fluid shift results in increased intracranial pressure, congested cerebral circulation, increased Cerebral Blood Flow (CBF) and Intravenous dilatation. The mechanism of the effect of CO2 on CBF is diagrammed, as is the Cerebrospinal Fluid (CSF) production. A listing of Neuroendocrine targets is included.

Distinct responses of soil microbial communities to elevated CO2 and O3 in a soybean agro-ecosystem.

Science.gov (United States)

He, Zhili; Xiong, Jinbo; Kent, Angela D; Deng, Ye; Xue, Kai; Wang, Gejiao; Wu, Liyou; Van Nostrand, Joy D; Zhou, Jizhong

2014-03-01

The concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have been rising due to human activities. However, little is known about how such increases influence soil microbial communities. We hypothesized that elevated CO2 (eCO2) and elevated O3 (eO3) would significantly affect the functional composition, structure and metabolic potential of soil microbial communities, and that various functional groups would respond to such atmospheric changes differentially. To test these hypotheses, we analyzed 96 soil samples from a soybean free-air CO2 enrichment (SoyFACE) experimental site using a comprehensive functional gene microarray (GeoChip 3.0). The results showed the overall functional composition and structure of soil microbial communities shifted under eCO2, eO3 or eCO2+eO3. Key functional genes involved in carbon fixation and degradation, nitrogen fixation, denitrification and methane metabolism were stimulated under eCO2, whereas those involved in N fixation, denitrification and N mineralization were suppressed under eO3, resulting in the fact that the abundance of some eO3-supressed genes was promoted to ambient, or eCO2-induced levels by the interaction of eCO2+eO3. Such effects appeared distinct for each treatment and significantly correlated with soil properties and soybean yield. Overall, our analysis suggests possible mechanisms of microbial responses to global atmospheric change factors through the stimulation of C and N cycling by eCO2, the inhibition of N functional processes by eO3 and the interaction by eCO2 and eO3. This study provides new insights into our understanding of microbial functional processes in response to global atmospheric change in soybean agro-ecosystems.

Effects of Electrical Stimulation in Sympathetic Neuron-Cardiomyocyte Co-cultures

Science.gov (United States)

Takeuchi, Akimasa; Tani, Hiromasa; Mori, Masahide; Moriguchi, Hiroyuki; Kotani, Kiyoshi; Lee, Jong-Kook; Noshiro, Makoto; Jimbo, Yasuhiko

The sympathetic nervous system is one of the principal sources for regulating cardiovascular functions. Little is known, however, about the network-level interactions between sympathetic neurons and cardiomyocytes. In this study, a semi-separated co-culture system of superior cervical ganglion (SCG) neurons and ventricular myocytes (VMs) was developed by using a polydimethylsyloxane (PDMS) chamber placed on a microelectrode-array (MEA) substrate. Neurites of SCG neurons passed through a conduit of the chamber and reached VMs. Evoked activities of SCG neurons were observed from several electrodes immediately after applying constant-voltage stimulation (1 V, 1 ms, biphasic square pulses) to SCG neurons by using 32 electrodes. Furthermore, this stimulation was applied to SCG neurons at the frequency of 1, 5 and 10 Hz. After applying these three kinds of stimulations, mean minute contraction rate of VMs increased with an increase in the frequency of stimulation. These results suggest that changes in contraction rate of VMs after applying electrical stimulations to SCG neurons depend on frequencies of these stimulations and that the heart-regulating mechanisms as well as that in the body were formed in this co-culture system.

Genital Sensory Stimulation Shifts Estradiol Intraoviductal Signaling from Nongenomic to Genomic Pathways, Independently from Prolactin Surges

Directory of Open Access Journals (Sweden)

C PEÑARROJA-MATUTAN0

2007-01-01

Full Text Available Estradiol (E2 accelerates oviductal egg transport through nongenomic pathways involving oviductal protein phosphorylation in non-mated rats, and through genomic pathways in mated rats. Here we investigated the ability of cervico-vaginal stimulation (CVS to switch the mode of action of E2 in the absence of other male-associated components. Pro-estrous rats were subjected to CVS with a glass rod and 12 hours later were injected subcutaneously with E2 and intrabursally with the RNA synthesis inhibitor Actinomycin D or the protein phosphorylation inhibitor H-89. The number of eggs in the oviduct, assessed 24 h later, showed that Actinomycin D, but not H-89 blocked the E2-induced egg transport acceleration. This clearly indicates that CVS alone, without other mating-associated signals, is able to shift E2 signaling from nongenomic to genomic pathways. Since mating and CVS activate a neuroendocrine reflex that causes iterative prolactin (PRL surges, the involvement of PRL pathway in this phenomenon was evaluated. Prolactin receptor mRNA and protein expression in the rat oviduct was demonstrated by RT-PCR and Western blot, but their levels were not different on day 2 of the cycle (C2 or pregnancy (P2. Activated ST AT 5a/b (phosphorylated was detected by Western blot on P2 in the ovary, but not in the oviduct, showing that mating does not stimulate this PRL signalling pathway in the oviduct. Other rats subjected to CVS in the evening of pro-estrus were treated with bromoergocriptine to suppress PRL surges. In these rats, H-89 did not block the E2-induced acceleration of egg transport suggesting that PRL surges are not essential to shift E2 signaling pathways in the oviduct. We conclude that CVS is one of the components of mating that shifts E2 signaling in the oviduct from nongenomic to genomic pathways, and this effect is independent of PRL surges elicited by mating

GABAergic modulation of DC stimulation-induced motor cortex excitability shifts in humans.

Science.gov (United States)

Nitsche, Michael A; Liebetanz, David; Schlitterlau, Anett; Henschke, Undine; Fricke, Kristina; Frommann, Kai; Lang, Nicolas; Henning, Stefan; Paulus, Walter; Tergau, Frithjof

2004-05-01

Weak transcranial DC stimulation (tDCS) of the human motor cortex results in excitability shifts during and after the end of stimulation, which are most probably localized intracortically. Anodal stimulation enhances excitability, whereas cathodal stimulation reduces it. Although the after-effects of tDCS are NMDA receptor-dependent, nothing is known about the involvement of additional receptors. Here we show that pharmacological strengthening of GABAergic inhibition modulates selectively the after-effects elicited by anodal tDCS. Administration of the GABA(A) receptor agonist lorazepam resulted in a delayed, but then enhanced and prolonged anodal tDCS-induced excitability elevation. The initial absence of an excitability enhancement under lorazepam is most probably caused by a loss of the anodal tDCS-generated intracortical diminution of inhibition and enhancement of facilitation, which occurs without pharmacological intervention. The reasons for the late-occurring excitability enhancement remain unclear. Because intracortical inhibition and facilitation are not changed in this phase compared with pre-tDCS values, excitability changes originating from remote cortical or subcortical areas could be involved.

INFLUENCE OF METRONIDAZOLE, CO, CO2, AND METHANOGENS ON THE FERMENTATIVE METABOLISM OF THE ANAEROBIC FUNGUS NEOCALLIMASTIX SP STRAIN L2

NARCIS (Netherlands)

MARVINSIKKEMA, FD; REES, E; KRAAK, MN; GOTTSCHAL, JC; PRINS, RA

The effects of metronidazole, CO, methanogens, and CO, on the fermentation of glucose by the anaerobic fungus Neocallimastix sp. strain L2 were investigated. Both metronidazole and CO caused a shift in the fermentation products from predominantly H-2, acetate, and formate to lactate as the major

Resonant stimulation of Raman scattering from single-crystal thiophene/phenylene co-oligomers

International Nuclear Information System (INIS)

Yanagi, Hisao; Marutani, Yusuke; Matsuoka, Naoki; Hiramatsu, Toru; Ishizumi, Atsushi; Sasaki, Fumio; Hotta, Shu

2013-01-01

Amplified Raman scattering was observed from single crystals of thiophene/phenylene co-oligomers (TPCOs). Under ns-pulsed excitation, the TPCO crystals exhibited amplified spontaneous emission (ASE) at resonant absorption wavelengths. With increasing excitation wavelength to the 0-0 absorption edge, the stimulated resonant Raman peaks appeared both in the 0-1 and 0-2 ASE band regions. When the excitation wavelength coincided with the 0-1 ASE band energy, the Raman peaks selectively appeared in the 0-2 ASE band. Such unusual enhancement of the 0-2 Raman scattering was ascribed to resonant stimulation via vibronic coupling with electronic transitions in the uniaxially oriented TPCO molecules

Effects of elevated CO{sub 2} on Chesapeake Bay wetlands. [Progress report, 1988--1989

Energy Technology Data Exchange (ETDEWEB)

Drake, B.G.; Arp, W.J.; Balduman, L.

1990-12-31

Research during 1988--89 focused on several new aspects of the response of the salt marsh ecosystem to elevated CO{sub 2}. In previous years we gave highest priority to studies of the effect of CO{sub 2} on biomass production into above and below-ground tissues, nitrogen content, light response of photosynthesis of single leaves, leaf water potential and carbon dioxide and water vapor exchange between the plant canopy and the ambient air. Result from the work in 87 and 88 had shown that the C3 plant, Scirpus olneyi, responded vigorously to elevated CO{sub 2} but the two C4 species, Spartina patens and Distichlis spicata did not. The responses of photosynthesis were also reflected in the canopy and ecosystem processes. Thus our emphasis shifted from determining the growth responses to exploring photosynthesis in greater detail. The main questions were: does acclimation to high CO{sub 2} involve reduction of some aspect of photosynthesis either at the single leaf level or in canopy structure? How much more carbon will be accumulated in a high CO{sub 2} than under present CO{sub 2} concentration? Our results give us partial answers to these questions but since the long term aspect of CO{sub 2} stimulation remains the most important one, it is unlikely that we can do more than add some pieces of data to a continuing debate in the ecological community regarding the eventual effect of CO{sub 2} on ecosystems.

The magnetization reversal in CoFe{sub 2}O{sub 4}/CoFe{sub 2} granular systems

Energy Technology Data Exchange (ETDEWEB)

Jin, J.; Sun, X.; Wang, M.; Ding, Z.L.; Ma, Y.Q., E-mail: yqma@ahu.edu.cn [Anhui University, Anhui Key Laboratory of Information Materials and Devices, School of Physics and Materials Science (China)

2016-12-15

The temperature-dependent field cooling (FC) and zero-field cooling (ZFC) magnetizations, i.e., M{sub FC} and M{sub ZFC}, measured under different magnetic fields from 500 Oe to 20 kOe have been investigated on two exchange–spring CoFe{sub 2}O{sub 4}/CoFe{sub 2} composites with different relative content of CoFe{sub 2}. Two samples exhibit different magnetization reversal behaviors. With decreasing temperature, a progressive freezing of the moments in two composites occurs at a field-dependent irreversible temperature T{sub irr}. For the sample with less CoFe{sub 2}, the curves of −d(M{sub FC} − M{sub ZFC})/dT versus temperature T exhibit a broad peak at an intermediate temperature T{sub 2} below T{sub irr}, and the moments are suggested not to fully freeze till the lowest measuring temperature 10 K. However, for the −d(M{sub FC} − M{sub ZFC})/dT curves of the sample with more CoFe{sub 2}, besides a broad peat at an intermediate temperature T{sub 2}, a rapid rise around the low temperature T{sub 1}~15 K is observed, below which the moments are suggested to fully freeze. Increase of magnetic field from 2 kOe leads to the shift of T{sub 2} and T{sub irr} towards a lower temperature, and the shift of T{sub 2} is attributable to the moment reversal of CoFe{sub 2}O{sub 4}.

Analytical study of nonlinear phase shift through stimulated Brillouin scattering in single mode fiber with the pump power recycling technique

International Nuclear Information System (INIS)

Al-Asadi, H A; Mahdi, M A; Bakar, A A A; Adikan, F R Mahamd

2011-01-01

We present a theoretical study of nonlinear phase shift through stimulated Brillouin scattering in single mode optical fiber. Analytical expressions describing the nonlinear phase shift for the pump and Stokes waves in the pump power recycling technique have been derived. The dependence of the nonlinear phase shift on the optical fiber length, the reflectivity of the optical mirror and the frequency detuning coefficient have been analyzed for different input pump power values. We found that with the recycling pump technique, the nonlinear phase shift due to stimulated Brillouin scattering reduced to less than 0.1 rad for 5 km optical fiber length and 0.65 reflectivity of the optical mirror, respectively, at an input pump power equal to 30 mW

Stable isotope and modelling evidence for CO2 as a driver of glacial–interglacial vegetation shifts in southern Africa

Directory of Open Access Journals (Sweden)

F. J. Bragg

2013-03-01

Full Text Available Atmospheric CO2 concentration is hypothesized to influence vegetation distribution via tree–grass competition, with higher CO2 concentrations favouring trees. The stable carbon isotope (δ13C signature of vegetation is influenced by the relative importance of C4 plants (including most tropical grasses and C3 plants (including nearly all trees, and the degree of stomatal closure – a response to aridity – in C3 plants. Compound-specific δ13C analyses of leaf-wax biomarkers in sediment cores of an offshore South Atlantic transect are used here as a record of vegetation changes in subequatorial Africa. These data suggest a large increase in C3 relative to C4 plant dominance after the Last Glacial Maximum. Using a process-based biogeography model that explicitly simulates 13C discrimination, it is shown that precipitation and temperature changes cannot explain the observed shift in δ13C values. The physiological effect of increasing CO2 concentration is decisive, altering the C3/C4 balance and bringing the simulated and observed δ13C values into line. It is concluded that CO2 concentration itself was a key agent of vegetation change in tropical southern Africa during the last glacial–interglacial transition. Two additional inferences follow. First, long-term variations in terrestrial δ13Cvalues are not simply a proxy for regional rainfall, as has sometimes been assumed. Although precipitation and temperature changes have had major effects on vegetation in many regions of the world during the period between the Last Glacial Maximum and recent times, CO2 effects must also be taken into account, especially when reconstructing changes in climate between glacial and interglacial states. Second, rising CO2 concentration today is likely to be influencing tree–grass competition in a similar way, and thus contributing to the "woody thickening" observed in savannas worldwide. This second inference points to the importance of experiments to

Response of soil CO2 efflux to precipitation manipulation in a semiarid grassland.

Science.gov (United States)

Wei, Xiaorong; Zhang, Yanjiang; Liu, Jian; Gao, Hailong; Fan, Jun; Jia, Xiaoxu; Cheng, Jimin; Shao, Mingan; Zhang, Xingchang

2016-07-01

Soil CO2 efflux (SCE) is an important component of ecosystem CO2 exchange and is largely temperature and moisture dependent, providing feedback between C cycling and the climate system. We used a precipitation manipulation experiment to examine the effects of precipitation treatment on SCE and its dependences on soil temperature and moisture in a semiarid grassland. Precipitation manipulation included ambient precipitation, decreased precipitation (-43%), or increased precipitation (+17%). The SCE was measured from July 2013 to December 2014, and CO2 emission during the experimental period was assessed. The response curves of SCE to soil temperature and moisture were analyzed to determine whether the dependence of SCE on soil temperature or moisture varied with precipitation manipulation. The SCE significantly varied seasonally but was not affected by precipitation treatments regardless of season. Increasing precipitation resulted in an upward shift of SCE-temperature response curves and rightward shift of SCE-moisture response curves, while decreasing precipitation resulted in opposite shifts of such response curves. These shifts in the SCE response curves suggested that increasing precipitation strengthened the dependence of SCE on temperature or moisture, and decreasing precipitation weakened such dependences. Such shifts affected the predictions in soil CO2 emissions for different precipitation treatments. When considering such shifts, decreasing or increasing precipitation resulted in 43 or 75% less change, respectively, in CO2 emission compared with changes in emissions predicted without considering such shifts. Furthermore, the effects of shifts in SCE response curves on CO2 emission prediction were greater during the growing than the non-growing season. Copyright © 2016. Published by Elsevier B.V.

Slow-oscillatory transcranial direct current stimulation can induce bidirectional shifts in motor cortical excitability in awake humans

DEFF Research Database (Denmark)

Groppa, S; Bergmann, T O; Siems, C

2010-01-01

Constant transcranial direct stimulation (c-tDCS) of the primary motor hand area (M1(HAND)) can induce bidirectional shifts in motor cortical excitability depending on the polarity of tDCS. Recently, anodal slow oscillation stimulation at a frequency of 0.75 Hz has been shown to augment intrinsic...... slow oscillations during sleep and theta oscillations during wakefulness. To embed this new type of stimulation into the existing tDCS literature, we aimed to characterize the after effects of slowly oscillating stimulation (so-tDCS) on M1(HAND) excitability and to compare them to those of c-tDCS. Here...

Broadening of spectral lines of CO2, N2O , H2CO, HCN, and H2S by pressure of gases dominant in planetary atmospheres (H2, He and CO2)

Science.gov (United States)

Samuels, Shanelle; Gordon, Iouli; Tan, Yan

2018-01-01

HITRAN1,2 is a compilation of spectroscopic parameters that a variety of computer codes use to predict and simulate the transmission and emission of light in planetary atmospheres. The goal of this project is to add to the potential of the HITRAN database towards the exploration of the planetary atmospheres by including parameters describing broadening of spectral lines by H2, CO2, and He. These spectroscopic data are very important for the study of the hydrogen and helium-rich atmospheres of gas giants as well as rocky planets with volcanic activities, including Venus and Mars, since their atmospheres are dominated by CO2. First step in this direction was accomplished by Wilzewski et al.3 where this was done for SO2, NH3, HF, HCl, OCS and C2H2. The molecules investigated in this work were CO2, N2O, H2CO, HCN and H2S. Line-broadening coefficients, line shifts and temperature-dependence exponents for transitions of these molecules perturbed by H2, CO2 and He have been assembled from available peer-reviewed experimental and theoretical sources. The data was evaluated and the database was populated with these data and their extrapolations/interpolations using semi-empirical models that were developed to this end.Acknowledgements: Financial support from NASA PDART grant NNX16AG51G and the Smithsonian Astrophysical Observatory Latino Initiative Program from the Latino Initiatives Pool, administered by the Smithsonian Latino Center is gratefully acknowledged.References: 1. HITRAN online http://hitran.org/2. Gordon, I.E., Rothman, L.S., Hill, C., Kochanov, R.V., Tan, Y., et al., 2017. The HITRAN2016 Molecular Spectroscopic Database. J. Quant. Spectrosc. Radiat. Transf. doi:10.1016/j.jqsrt.2017.06.0383. Wilzewski, J.S., Gordon, I.E., Kochanov, R. V., Hill, C., Rothman, L.S., 2016. H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2. J. Quant. Spectrosc. Radiat

Foraminiferal calcification and CO2

Science.gov (United States)

Nooijer, L. D.; Toyofuku, T.; Reichart, G. J.

2017-12-01

Ongoing burning of fossil fuels increases atmospheric CO2, elevates marine dissolved CO2 and decreases pH and the saturation state with respect to calcium carbonate. Intuitively this should decrease the ability of CaCO3-producing organisms to build their skeletons and shells. Whereas on geological time scales weathering and carbonate deposition removes carbon from the geo-biosphere, on time scales up to thousands of years, carbonate precipitation increases pCO2 because of the associated shift in seawater carbon speciation. Hence reduced calcification provides a potentially important negative feedback on increased pCO2 levels. Here we show that foraminifera form their calcium carbonate by active proton pumping. This elevates the internal pH and acidifies the direct foraminiferal surrounding. This also creates a strong pCO2 gradient and facilitates the uptake of DIC in the form of carbon dioxide. This finding uncouples saturation state from calcification and predicts that the added carbon due to ocean acidification will promote calcification by these organisms. This unknown effect could add substantially to atmospheric pCO2 levels, and might need to be accounted for in future mitigation strategies.

CO2 reduction: is increasing the diesel share the way to go?

NARCIS (Netherlands)

Rijkeboer, R.C.; Havenith, C.; Baarbe, H.L.

1998-01-01

Different scenarios have been compared for the future reduction of CO2-emission under real-world driving conditions. A significant shift towards diesel appears hardly to benefit the CO2 but would carry a real NOx penalty. Introduction of DI petrol engines and a shift towards gaseous fuels for s.i.

The Value of CO2-Geothermal Bulk Energy Storage to Reducing CO2 Emissions Compared to Conventional Bulk Energy Storage Technologies

Science.gov (United States)

Ogland-Hand, J.; Bielicki, J. M.; Buscheck, T. A.

2016-12-01

Sedimentary basin geothermal resources and CO2 that is captured from large point sources can be used for bulk energy storage (BES) in order to accommodate higher penetration and utilization of variable renewable energy resources. Excess energy is stored by pressurizing and injecting CO2 into deep, porous, and permeable aquifers that are ubiquitous throughout the United States. When electricity demand exceeds supply, some of the pressurized and geothermally-heated CO2 can be produced and used to generate electricity. This CO2-BES approach reduces CO2 emissions directly by storing CO2 and indirectly by using some of that CO2 to time-shift over-generation and displace CO2 emissions from fossil-fueled power plants that would have otherwise provided electricity. As such, CO2-BES may create more value to regional electricity systems than conventional pumped hydro energy storage (PHES) or compressed air energy storage (CAES) approaches that may only create value by time-shifting energy and indirectly reducing CO2 emissions. We developed and implemented a method to estimate the value that BES has to reducing CO2 emissions from regional electricity systems. The method minimizes the dispatch of electricity system components to meet exogenous demand subject to various CO2 prices, so that the value of CO2 emissions reductions can be estimated. We applied this method to estimate the performance and value of CO2-BES, PHES, and CAES within real data for electricity systems in California and Texas over the course of a full year to account for seasonal fluctuations in electricity demand and variable renewable resource availability. Our results suggest that the value of CO2-BES to reducing CO2 emissions may be as much as twice that of PHES or CAES and thus CO2-BES may be a more favorable approach to energy storage in regional electricity systems, especially those where the topography is not amenable to PHES or the subsurface is not amenable to CAES.

Frequency shifts in stimulated Raman scattering

International Nuclear Information System (INIS)

Zinth, W.; Kaiser, W.

1980-01-01

The nonresonant contributions to the nonlinear susceptibility chisup(()3) produce a frequency chirp during stimulated Raman scattering. In the case of transient stimulated Raman scattering, the spectrum of the generated Stokes pulse is found at higher frequencies than expected from spontaneous Raman data. The frequency difference can be calculated from the theory of stimulated Raman scattering. (orig.)

Global CO2 fluxes estimated from GOSAT retrievals of total column CO2

Directory of Open Access Journals (Sweden)

S. Basu

2013-09-01

Full Text Available We present one of the first estimates of the global distribution of CO2 surface fluxes using total column CO2 measurements retrieved by the SRON-KIT RemoTeC algorithm from the Greenhouse gases Observing SATellite (GOSAT. We derive optimized fluxes from June 2009 to December 2010. We estimate fluxes from surface CO2 measurements to use as baselines for comparing GOSAT data-derived fluxes. Assimilating only GOSAT data, we can reproduce the observed CO2 time series at surface and TCCON sites in the tropics and the northern extra-tropics. In contrast, in the southern extra-tropics GOSAT XCO2 leads to enhanced seasonal cycle amplitudes compared to independent measurements, and we identify it as the result of a land–sea bias in our GOSAT XCO2 retrievals. A bias correction in the form of a global offset between GOSAT land and sea pixels in a joint inversion of satellite and surface measurements of CO2 yields plausible global flux estimates which are more tightly constrained than in an inversion using surface CO2 data alone. We show that assimilating the bias-corrected GOSAT data on top of surface CO2 data (a reduces the estimated global land sink of CO2, and (b shifts the terrestrial net uptake of carbon from the tropics to the extra-tropics. It is concluded that while GOSAT total column CO2 provide useful constraints for source–sink inversions, small spatiotemporal biases – beyond what can be detected using current validation techniques – have serious consequences for optimized fluxes, even aggregated over continental scales.

Optimizing CO2 avoided cost by means of repowering

International Nuclear Information System (INIS)

Escosa, Jesus M.; Romeo, Luis M.

2009-01-01

Repowering fossil fuel power plants by means of gas turbines has been traditionally considered to increase power output and reduce NO x and SO 2 emissions both at low cost and short outage periods. At present, reduction in CO 2 emissions represents an additional advantage of repowering due to partial fuel shift and overall efficiency increase. This is especially important in existing installations with a CO 2 reduction mandatory that should be carried out in a short time and in a cost-effective manner. Feedwater and parallel repowering schemes have been analysed using thermodynamic, environmental and economic simulations. The objective is not only to evaluate the cost of electricity and the efficiency increase of the overall system, but calculate and minimize the cost of CO 2 avoided as a function of gas turbine power output. It seems that integration of larger gas turbines reduces the overall CO 2 emissions, but there is a compromise between CO 2 reduction due to fuel shift and a optimum integration of waste heat into the power plant to minimize the CO 2 avoided costs. Results highlight the repowering as a suitable technology to reduce 10-30% of CO 2 emissions in existing power plants with cost well below 20 Euro /tCO 2 . It could help to control emissions up to the carbon capture technologies commercial development.

Co-morbidity and patterns of care in stimulant-treated children with ADHD in the Netherlands

NARCIS (Netherlands)

Faber, Adrianne; Kalverdijk, Luuk J.; de Jong-van den Berg, Lolkje T. W.; Hugtenburg, Jacqueline G.; Minderaa, Ruud B.; Tobi, Hilde

This study aimed at investigating the use of psychosocial interventions and psychotropic co-medication among stimulant-treated children with attention-deficit hyperactivity disorder (ADHD) in relation to the presence of psychiatric co-morbidity. Stimulant users younger than 16 years were identified

Co-morbidity and patterns of care in stimulant-treated children with ADHD in the Netherlands

NARCIS (Netherlands)

Faber, A.; Kalverdijk, L.J.; de Jong-van den Berg, L.T.W.; Hugtenburg, J.G.; Minderaa, R.B.; Tobi, H.

2010-01-01

This study aimed at investigating the use of psychosocial interventions and psychotropic co-medication among stimulant-treated children with attention-deficit hyperactivity disorder (ADHD) in relation to the presence of psychiatric co-morbidity. Stimulant users younger than 16 years were identified

Novel concepts for CO2 capture

International Nuclear Information System (INIS)

Dijkstra, J.W.; Jansen, D.

2004-01-01

This paper describes the possibilities for power generation with CO 2 capture using envisaged key technologies: gas turbines, membranes and solid oxide fuel cells (SOFCs). First, the underlying programs in the Netherlands and at ECN are introduced. Then the key technologies are introduced, and concepts using these technologies are discussed. A literature overview of systems for power generation with fuel cells in combination with CO 2 capture is presented. Then a novel concept is introduced. This concept uses a water gas shift membrane reactor to convert the CO and H 2 in the SOFC anode off-gas to gain a CO 2 rich stream, which can be used for sequestration without elaborate treatment. Several implementation schemes of the technique are discussed such as atmospheric systems and hybrid SOFC-GT systems

Co-morbidity and patterns of care in stimulant-treated children with ADHD in the Netherlands.

Science.gov (United States)

Faber, Adrianne; Kalverdijk, Luuk J; de Jong-van den Berg, Lolkje T W; Hugtenburg, Jacqueline G; Minderaa, Ruud B; Tobi, Hilde

2010-02-01

This study aimed at investigating the use of psychosocial interventions and psychotropic co-medication among stimulant-treated children with attention-deficit hyperactivity disorder (ADHD) in relation to the presence of psychiatric co-morbidity. Stimulant users younger than 16 years were identified in 115 pharmacies and a questionnaire was sent to their stimulant prescribing physician. Of 773 questionnaires sent out, 556 were returned and were suitable for analysis (72%). The results are based on 510 questionnaires concerning stimulant-treated children for whom a diagnosis of ADHD was reported. Of the 510 children diagnosed with ADHD, 31% had also received one or more other psychiatric diagnoses, mainly pervasive developmental disorder or oppositional defiant disorder/conduct disorder. We found an association between the presence of co-morbidity and the use of psychosocial interventions for the child (P parents (P receive any form of additional interventions, while psychosocial interventions varied from 8 to 18% in children with ADHD and psychiatric co-morbidity. The presence of diagnostic co-morbidity was also associated with the use of psychotropic co-medication (overall, P = 0.012) and antipsychotics (P received more psychosocial interventions and psychotropic co-medication than children with ADHD-only. The type of psychosocial interventions and psychotropic co-medication received by the children and their parents, depended on the specific co-morbid psychiatric disorder being present.

Does calcium influx regulate melatonin production through the circadian pacemaker in chick pineal cells? Effects of nitrendipine, Bay K 8644, Co2+, Mn2+, and low external Ca2+.

Science.gov (United States)

Zatz, M; Mullen, D A

1988-11-01

We have recently described a system, using dispersed chick pineal cells in static culture, which displays a persistent, photosensitive, circadian rhythm of melatonin production and release. Here, we describe the effects of nitrendipine (NTR) (a dihydropyridine 'antagonist' of L-type calcium channels), Bay K 8644 (BK) (a dihydropyridine calcium channel 'agonist'), cobalt and manganese ions (both inorganic calcium channel blockers), and low external calcium concentrations, on the melatonin rhythm. NTR inhibited and BK stimulated melatonin output; they were potent and effective. Co2+, Mn2+, and low external Ca2+ markedly inhibited melatonin output. These results support a role for calcium influx through voltage-dependent calcium channels (L-type) in the regulation of melatonin production. Four or 8 h pulses of white light or darkness, in otherwise constant red light, cause, in addition to acute effects, phase-dependent phase shifts of the melatonin rhythm in subsequent cycles. Such phase shifts indicate an effect on (proximal to) the pacemaker generating the rhythm. Four or 8 h pulses of NTR, BK, Co2+, or low Ca2+, however, did not appreciably alter the phase of subsequent melatonin cycles. Neither did BK interfere with phase shifts induced by light pulses. Mn2+ pulses did induce phase-dependent phase shifts, but, unlike those evoked by light or dark pulses, these were all delays. Such effects of Mn2+ in other systems have been attributed to, and are characteristic of, 'metabolic inhibitors'. On balance, the results fail to support a prominent role for calcium influx in regulating the pacemaker underlying the circadian rhythm in chick pineal cells. Rather, calcium influx appears to regulate melatonin production primarily by acting on the melatonin-synthesizing apparatus, distal to the pacemaker.

Monitoring the bio-stimulation of hydrocarbon-contaminated soils by measurements of soil electrical properties, and CO2 content and its 13C/12C isotopic signature

Science.gov (United States)

Noel, C.; Gourry, J.; Ignatiadis, I.; Colombano, S.; Dictor, M.; Guimbaud, C.; Chartier, M.; Dumestre, A.; Dehez, S.; Naudet, V.

2013-12-01

Hydrocarbon contaminated soils represent an environmental issue as it impacts on ecosystems and aquifers. Where significant subsurface heterogeneity exists, conventional intrusive investigations and groundwater sampling can be insufficient to obtain a robust monitoring of hydrocarbon contaminants, as the information they provide is restricted to vertical profiles at discrete locations, with no information between sampling points. In order to obtain wider information in space volume on subsurface modifications, complementary methods can be used like geophysics. Among geophysical methods, geoelectrical techniques such as electrical resistivity (ER) and induced polarization (IP) seem the more promising, especially to study the effects of biodegradation processes. Laboratory and field geoelectrical experiments to characterize soils contaminated by oil products have shown that mature hydrocarbon-contaminated soils are characterized by enhanced electrical conductivity although hydrocarbons are electrically resistive. This high bulk conductivity is due to bacterial impacts on geological media, resulting in changes in the chemical and physical properties and thus, to the geophysical properties of the ground. Moreover, microbial activity induced CO2 production and isotopic deviation of carbon. Indeed, produced CO2 will reflect the pollutant isotopic signature. Thus, the ratio δ13C(CO2) will come closer to δ13C(hydrocarbon). BIOPHY, project supported by the French National Research Agency (ANR), proposes to use electrical methods and gas analyses to develop an operational and non-destructive method for monitoring in situ biodegradation of hydrocarbons in order to optimize soil treatment. Demonstration field is located in the South of Paris (France), where liquid fuels (gasoline and diesel) leaked from some tanks in 1997. In order to stimulate biodegradation, a trench has been dug to supply oxygen to the water table and thus stimulate aerobic metabolic bioprocesses. ER and

Electrical and optical co-stimulation in the deaf white cat

Science.gov (United States)

Cao, Zhiping; Xu, Yingyue; Tan, Xiaodong; Suematsu, Naofumi; Robinson, Alan; Richter, Claus-Peter

2018-02-01

Spatial selectivity of neural stimulation with photons, such as infrared neural stimulation (INS) is higher than the selectivity obtained with electrical stimulation. To obtain more independent channels for stimulation in neural prostheses, INS may be implemented to better restore the fidelity of the damaged neural system. However, irradiation with infrared light also bares the risk of heat accumulation in the target tissue with subsequent neural damage. Lowering the threshold for stimulation could reduce the amount of heat delivered to the tissue and the risk for subsequent tissue damage. It has been shown in the rat sciatic nerve that simultaneous irradiation with infrared light and the delivery of biphasic sub-threshold electrical pulses can reduce the threshold for INS [1]. In this study, deaf white cats have been used to test whether opto-electrical co-stimulation can reduce the stimulation threshold for INS in the auditory system too. The cochleae of the deaf white cats have largely reduced spiral ganglion neuron counts and significant degeneration of the organ of Corti and do not respond to acoustic stimuli. Combined electrical and optical stimulation was used to demonstrate that simultaneous stimulation with infrared light and biphasic electrical pulses can reduce the threshold for stimulation.

Strong shift from HCO3 (-) to CO 2 uptake in Emiliania huxleyi with acidification: new approach unravels acclimation versus short-term pH effects.

Science.gov (United States)

Kottmeier, Dorothee M; Rokitta, Sebastian D; Tortell, Philippe D; Rost, Björn

2014-09-01

Effects of ocean acidification on Emiliania huxleyi strain RCC 1216 (calcifying, diploid life-cycle stage) and RCC 1217 (non-calcifying, haploid life-cycle stage) were investigated by measuring growth, elemental composition, and production rates under different pCO2 levels (380 and 950 μatm). In these differently acclimated cells, the photosynthetic carbon source was assessed by a (14)C disequilibrium assay, conducted over a range of ecologically relevant pH values (7.9-8.7). In agreement with previous studies, we observed decreased calcification and stimulated biomass production in diploid cells under high pCO2, but no CO2-dependent changes in biomass production for haploid cells. In both life-cycle stages, the relative contributions of CO2 and HCO3 (-) uptake depended strongly on the assay pH. At pH values ≤ 8.1, cells preferentially used CO2 (≥ 90 % CO2), whereas at pH values ≥ 8.3, cells progressively increased the fraction of HCO3 (-) uptake (~45 % CO2 at pH 8.7 in diploid cells; ~55 % CO2 at pH 8.5 in haploid cells). In contrast to the short-term effect of the assay pH, the pCO2 acclimation history had no significant effect on the carbon uptake behavior. A numerical sensitivity study confirmed that the pH-modification in the (14)C disequilibrium method yields reliable results, provided that model parameters (e.g., pH, temperature) are kept within typical measurement uncertainties. Our results demonstrate a high plasticity of E. huxleyi to rapidly adjust carbon acquisition to the external carbon supply and/or pH, and provide an explanation for the paradoxical observation of high CO2 sensitivity despite the apparently high HCO3 (-) usage seen in previous studies.

Transcranial Direct Current Stimulation and Power Spectral Parameters: a tDCS/EEG co-registration study

Directory of Open Access Journals (Sweden)

Anna Lisa Mangia

2014-08-01

Full Text Available Transcranial direct current stimulation (tDCS delivers low electric currents to the brain through the scalp. Constant electric currents induce shifts in neuronal membrane excitability, resulting in secondary changes in cortical activity. Concomitant electroencephalography (EEG monitoring during tDCS can provide valuable information on the tDCS mechanisms of action. This study examined the effects of anodal tDCS on spontaneous cortical activity in a resting brain to disclose possible modulation of spontaneous oscillatory brain activity. EEG activity was measured in ten healthy subjects during and after a session of anodal stimulation of the postero-parietal cortex to detect the tDCS-induced alterations. Changes in the theta, alpha, beta and gamma power bands were investigated. Three main findings emerged: 1 an increase in theta band activity during the first minutes of stimulation; 2 an increase in alpha and beta power during and after stimulation; 3 a widespread activation in several brain regions.

Strategies for 2nd generation biofuels in EU - Co-firing to stimulate feedstock supply development and process integration to improve energy efficiency and economic competitiveness

International Nuclear Information System (INIS)

Berndes, Goeran; Hansson, Julia; Egeskog, Andrea; Johnsson, Filip

2010-01-01

The present biofuel policies in the European Union primarily stimulate 1st generation biofuels that are produced based on conventional food crops. They may be a distraction from lignocellulose based 2nd generation biofuels - and also from biomass use for heat and electricity - by keeping farmers' attention and significant investments focusing on first generation biofuels and the cultivation of conventional food crops as feedstocks. This article presents two strategies that can contribute to the development of 2nd generation biofuels based on lignocellulosic feedstocks. The integration of gasification-based biofuel plants in district heating systems is one option for increasing the energy efficiency and improving the economic competitiveness of such biofuels. Another option, biomass co-firing with coal, generates high-efficiency biomass electricity and reduces CO 2 emissions by replacing coal. It also offers a near-term market for lignocellulosic biomass, which can stimulate development of supply systems for biomass also suitable as feedstock for 2nd generation biofuels. Regardless of the long-term priorities of biomass use for energy, the stimulation of lignocellulosic biomass production by development of near term and cost-effective markets is judged to be a no-regrets strategy for Europe. Strategies that induce a relevant development and exploit existing energy infrastructures in order to reduce risk and reach lower costs, are proposed an attractive complement the present and prospective biofuel policies. (author)

Financial Rewards Do Not Stimulate Co-Production: Evidence from Two Experiments : Fortcoming in Public Administration review

NARCIS (Netherlands)

W.H. Voorberg (William); S.R. Jilke (Sebastian); L.G. Tummers (Lars); V.J.J.M. Bekkers (Victor)

2017-01-01

textabstractWestern governments are increasingly trying to stimulate citizens to ‘co-produce’ public services, among others, by offering them financial incentives. However, there are competing views on whether financial incentives stimulate co-production. While some argue it increases citizens’

CO/sub 2/ carbon cycle and climate interactions

Energy Technology Data Exchange (ETDEWEB)

Grassl, H; Maier-Reimer, E; Degens, E T; Kempe, S; Spitzy, A

1984-03-01

Past and expected emissions of anthropogenic CO/sub 2/ stimulate carbon cycle and climate research. Prognoses of future CO/sub 2/ levels depend on energy scenarios and on the reaction of the biosphere and hydrosphere to elevated atmospheric CO/sub 2/ concentrations. The reaction of the reservoirs vegetation, freshwater and oceans to disturbances of the carbon cycle is reviewed. For the oceans first results of a simple carbon cycle model implanted in a three-dimensional general circulation model are presented. This model allows experiments not possible with previous box models.

Chemisorption of H2O and CO2 on hydrotalcites for sorptionenhanced water-gas-shift processes

NARCIS (Netherlands)

Coenen, K.T.; Gallucci, F.; Cobden, P.; van Dijk, E.; Hensen, E.J.M.; van Sint Annaland, M.

2016-01-01

Thermogravimetric analysis and breakthrough experiments in a packed bed reactor were used to validate a developed adsorption model to describe the cyclic working capacity of CO¬2 and H2O on a potassium-promoted hydrotalcite, a very promising adsorbent for sorption-enhanced water-gas-shift

Mixed Signals: Co-Stimulation in Invariant Natural Killer T Cell-Mediated Cancer Immunotherapy

Directory of Open Access Journals (Sweden)

Susannah C. Shissler

2017-11-01

Full Text Available Invariant natural killer T (iNKT cells are an integral component of the immune system and play an important role in antitumor immunity. Upon activation, iNKT cells can directly kill malignant cells as well as rapidly produce cytokines that stimulate other immune cells, making them a front line defense against tumorigenesis. Unfortunately, iNKT cell number and activity are reduced in multiple cancer types. This anergy is often associated with upregulation of co-inhibitory markers such as programmed death-1. Similar to conventional T cells, iNKT cells are influenced by the conditions of their activation. Conventional T cells receive signals through the following three types of receptors: (1 T cell receptor (TCR, (2 co-stimulation molecules, and (3 cytokine receptors. Unlike conventional T cells, which recognize peptide antigen presented by MHC class I or II, the TCRs of iNKT cells recognize lipid antigen in the context of the antigen presentation molecule CD1d (Signal 1. Co-stimulatory molecules can positively and negatively influence iNKT cell activation and function and skew the immune response (Signal 2. This study will review the background of iNKT cells and their co-stimulatory requirements for general function and in antitumor immunity. We will explore the impact of monoclonal antibody administration for both blocking inhibitory pathways and engaging stimulatory pathways on iNKT cell-mediated antitumor immunity. This review will highlight the incorporation of co-stimulatory molecules in antitumor dendritic cell vaccine strategies. The use of co-stimulatory intracellular signaling domains in chimeric antigen receptor-iNKT therapy will be assessed. Finally, we will explore the influence of innate-like receptors and modification of immunosuppressive cytokines (Signal 3 on cancer immunotherapy.

Stimulated resonant scattering at stressed fused silica surface

International Nuclear Information System (INIS)

Bouchut, Philippe; Reymermier, Maryse

2015-01-01

The radiative emission in CO 2 laser heated stressed fused silica is radically modified when gold microspheres are on the surface. At high heating rates, the emission dynamics changes from thermoluminescence to stimulated resonant scattering with an emission rate that is increased tenfold and the near infrared (NIR) spectrum is red-shifted. We show that the dynamic tensile stress that rises in heated silica is coupled with a fluctuating electromagnetic field that enables electromagnetic friction between moving OH emitters from silica bulk and NIR resonant scatterers at the silica surface. (paper)

Id1 expression promotes peripheral CD4{sup +} T cell proliferation and survival upon TCR activation without co-stimulation

Energy Technology Data Exchange (ETDEWEB)

Liu, Chen; Jin, Rong [Department of Immunology, Peking University Health Science Center, Beijing (China); Wang, Hong-Cheng [Oklahoma Medical Research Foundation, Oklahoma City, OK (United States); Tang, Hui; Liu, Yuan-Feng; Qian, Xiao-Ping; Sun, Xiu-Yuan; Ge, Qing [Department of Immunology, Peking University Health Science Center, Beijing (China); Sun, Xiao-Hong, E-mail: sunx@omrf.org [Oklahoma Medical Research Foundation, Oklahoma City, OK (United States); Zhang, Yu, E-mail: zhangyu007@bjmu.edu.cn [Department of Immunology, Peking University Health Science Center, Beijing (China)

2013-06-21

Highlights: •Id1 expression enables naïve T cell proliferation without anti-CD28 co-stimulation. •Id1 expression facilitates T cells survival when stimulated with anti-CD3. •Elevation of IL-2 production by Id1 contributes increased proliferation and survival. •Id1 potentiates NF-κB activation by anti-CD3 stimulation. -- Abstract: Although the role of E proteins in the thymocyte development is well documented, much less is known about their function in peripheral T cells. Here we demonstrated that CD4 promoter-driven transgenic expression of Id1, a naturally occurring dominant-negative inhibitor of E proteins, can substitute for the co-stimulatory signal delivered by CD28 to facilitate the proliferation and survival of naïve CD4{sup +} cells upon anti-CD3 stimulation. We next discovered that IL-2 production and NF-κB activity after anti-CD3 stimulation were significantly elevated in Id1-expressing cells, which may be, at least in part, responsible for the augmentation of their proliferation and survival. Taken together, results from this study suggest an important role of E and Id proteins in peripheral T cell activation. The ability of Id proteins to by-pass co-stimulatory signals to enable T cell activation has significant implications in regulating T cell immunity.

Measurement of Cerenkov Radiation Induced by the Gamma-Rays of Co-60 Therapy Units Using Wavelength Shifting Fiber

Directory of Open Access Journals (Sweden)

Kyoung Won Jang

2014-04-01

Full Text Available In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%.

Partially non-linear stimulation intensity-dependent effects of direct current stimulation on motor cortex excitability in humans.

Science.gov (United States)

Batsikadze, G; Moliadze, V; Paulus, W; Kuo, M-F; Nitsche, M A

2013-04-01

Transcranial direct current stimulation (tDCS) of the human motor cortex at an intensity of 1 mA with an electrode size of 35 cm(2) has been shown to induce shifts of cortical excitability during and after stimulation. These shifts are polarity-specific with cathodal tDCS resulting in a decrease and anodal stimulation in an increase of cortical excitability. In clinical and cognitive studies, stronger stimulation intensities are used frequently, but their physiological effects on cortical excitability have not yet been explored. Therefore, here we aimed to explore the effects of 2 mA tDCS on cortical excitability. We applied 2 mA anodal or cathodal tDCS for 20 min on the left primary motor cortex of 14 healthy subjects. Cathodal tDCS at 1 mA and sham tDCS for 20 min was administered as control session in nine and eight healthy subjects, respectively. Motor cortical excitability was monitored by transcranial magnetic stimulation (TMS)-elicited motor-evoked potentials (MEPs) from the right first dorsal interosseous muscle. Global corticospinal excitability was explored via single TMS pulse-elicited MEP amplitudes, and motor thresholds. Intracortical effects of stimulation were obtained by cortical silent period (CSP), short latency intracortical inhibition (SICI) and facilitation (ICF), and I wave facilitation. The above-mentioned protocols were recorded both before and immediately after tDCS in randomized order. Additionally, single-pulse MEPs, motor thresholds, SICI and ICF were recorded every 30 min up to 2 h after stimulation end, evening of the same day, next morning, next noon and next evening. Anodal as well as cathodal tDCS at 2 mA resulted in a significant increase of MEP amplitudes, whereas 1 mA cathodal tDCS decreased corticospinal excitability. A significant shift of SICI and ICF towards excitability enhancement after both 2 mA cathodal and anodal tDCS was observed. At 1 mA, cathodal tDCS reduced single-pulse TMS-elicited MEP amplitudes and shifted SICI

Theoretical perspectives on central chemosensitivity: CO2/H+-sensitive neurons in the locus coeruleus.

Directory of Open Access Journals (Sweden)

Maria C Quintero

2017-12-01

Full Text Available Central chemoreceptors are highly sensitive neurons that respond to changes in pH and CO2 levels. An increase in CO2/H+ typically reflects a rise in the firing rate of these neurons, which stimulates an increase in ventilation. Here, we present an ionic current model that reproduces the basic electrophysiological activity of individual CO2/H+-sensitive neurons from the locus coeruleus (LC. We used this model to explore chemoreceptor discharge patterns in response to electrical and chemical stimuli. The modeled neurons showed both stimulus-evoked activity and spontaneous activity under physiological parameters. Neuronal responses to electrical and chemical stimulation showed specific firing patterns of spike frequency adaptation, postinhibitory rebound, and post-stimulation recovery. Conversely, the response to chemical stimulation alone (based on physiological CO2/H+ changes, in the absence of external depolarizing stimulation, showed no signs of postinhibitory rebound or post-stimulation recovery, and no depolarizing sag. A sensitivity analysis for the firing-rate response to the different stimuli revealed that the contribution of an applied stimulus current exceeded that of the chemical signals. The firing-rate response increased indefinitely with injected depolarizing current, but reached saturation with chemical stimuli. Our computational model reproduced the regular pacemaker-like spiking pattern, action potential shape, and most of the membrane properties that characterize CO2/H+-sensitive neurons from the locus coeruleus. This validates the model and highlights its potential as a tool for studying the cellular mechanisms underlying the altered central chemosensitivity present in a variety of disorders such as sudden infant death syndrome, depression, and anxiety. In addition, the model results suggest that small external electrical signals play a greater role in determining the chemosensitive response to changes in CO2/H+ than previously

Influence of Hydrological Perturbations and Riverbed Sediment Characteristics on Hyporheic Zone Respiration of CO2 and N2

Science.gov (United States)

Newcomer, Michelle E.; Hubbard, Susan S.; Fleckenstein, Jan H.; Maier, Ulrich; Schmidt, Christian; Thullner, Martin; Ulrich, Craig; Flipo, Nicolas; Rubin, Yoram

2018-03-01

Rivers in climatic zones characterized by dry and wet seasons often experience periodic transitions between losing and gaining conditions across the river-aquifer continuum. Infiltration shifts can stimulate hyporheic microbial biomass growth and cycling of riverine carbon and nitrogen leading to major exports of biogenic CO2 and N2 to rivers. In this study, we develop and test a numerical model that simulates biological-physical feedback in the hyporheic zone. We used the model to explore different initial conditions in terms of dissolved organic carbon availability, sediment characteristics, and stochastic variability in aerobic and anaerobic conditions from water table fluctuations. Our results show that while highly losing rivers have greater hyporheic CO2 and N2 production, gaining rivers allowed the greatest fraction of CO2 and N2 production to return to the river. Hyporheic aerobic respiration and denitrification contributed 0.1-2 g/m2/d of CO2 and 0.01-0.2 g/m2/d of N2; however, the suite of potential microbial behaviors varied greatly among sediment characteristics. We found that losing rivers that consistently lacked an exit pathway can store up to 100% of the entering C/N as subsurface biomass and dissolved gas. Our results demonstrate the importance of subsurface feedbacks whereby microbes and hydrology jointly control fate of C and N and are strongly linked to wet-season control of initial sediment conditions and hydrologic control of seepage direction. These results provide a new understanding of hydrobiological and sediment-based controls on hyporheic zone respiration, including a new explanation for the occurrence of anoxic microzones and large denitrification rates in gravelly riverbeds.

Photosynthetic responses to elevated CO2 and O3 in Quercus ilex leaves at a natural CO2 spring

International Nuclear Information System (INIS)

Paoletti, E.; Seufert, G.; Della Rocca, G.; Thomsen, H.

2007-01-01

Photosynthetic stimulation and stomatal conductance (Gs) depression in Quercus ilex leaves at a CO 2 spring suggested no down-regulation. The insensitivity of Gs to a CO 2 increase (from ambient 1500 to 2000 μmol mol -1 ) suggested stomatal acclimation. Both responses are likely adaptations to the special environment of CO 2 springs. At the CO 2 -enriched site, not at the control site, photosynthesis decreased 9% in leaves exposed to 2x ambient O 3 concentrations in branch enclosures, compared to controls in charcoal-filtered air. The stomatal density reduction at high CO 2 was one-third lower than the concomitant Gs reduction, so that the O 3 uptake per single stoma was lower than at ambient CO 2 . No significant variation in monoterpene emission was measured. Higher trichome and mesophyll density were recorded at the CO 2 -enriched site, accounting for lower O 3 sensitivity. A long-term exposure to H 2 S, reflected by higher foliar S-content, and CO 2 might depress the antioxidant capacity of leaves close to the vent and increase their O 3 sensitivity. - Very high CO 2 concentrations did not compensate for the effects of O 3 on holm oak photosynthesis

Quantum-Chemical Approach to NMR Chemical Shifts in Paramagnetic Solids Applied to LiFePO4 and LiCoPO4.

Science.gov (United States)

Mondal, Arobendo; Kaupp, Martin

2018-04-05

A novel protocol to compute and analyze NMR chemical shifts for extended paramagnetic solids, accounting comprehensively for Fermi-contact (FC), pseudocontact (PC), and orbital shifts, is reported and applied to the important lithium ion battery cathode materials LiFePO 4 and LiCoPO 4 . Using an EPR-parameter-based ansatz, the approach combines periodic (hybrid) DFT computation of hyperfine and orbital-shielding tensors with an incremental cluster model for g- and zero-field-splitting (ZFS) D-tensors. The cluster model allows the use of advanced multireference wave function methods (such as CASSCF or NEVPT2). Application of this protocol shows that the 7 Li shifts in the high-voltage cathode material LiCoPO 4 are dominated by spin-orbit-induced PC contributions, in contrast with previous assumptions, fundamentally changing interpretations of the shifts in terms of covalency. PC contributions are smaller for the 7 Li shifts of the related LiFePO 4 , where FC and orbital shifts dominate. The 31 P shifts of both materials finally are almost pure FC shifts. Nevertheless, large ZFS contributions can give rise to non-Curie temperature dependences for both 7 Li and 31 P shifts.

NKG2D performs two functions in invariant NKT cells: direct TCR-independent activation of NK-like cytolysis and co-stimulation of activation by CD1d.

Science.gov (United States)

Kuylenstierna, Carlotta; Björkström, Niklas K; Andersson, Sofia K; Sahlström, Peter; Bosnjak, Lidija; Paquin-Proulx, Dominic; Malmberg, Karl-Johan; Ljunggren, Hans-Gustaf; Moll, Markus; Sandberg, Johan K

2011-07-01

Invariant NKT cells are important in the activation and regulation of immune responses. They can also function as CD1d-restricted killer cells. However, the role of activating innate NK-cell receptors expressed on NKT cells in triggering cytolytic function is poorly characterized. Here, we initially confirmed that the cellular stress-ligand receptor NKG2D is expressed on CD4- NKT cells, whereas most CD4+ NKT cells lack this receptor. Interestingly, NKG2D+ NKT cells frequently expressed perforin, and both NKG2D and perforin localized at the site of contact with NKG2D ligand-expressing target cells. CD4- NKT cells degranulated in response to NKG2D engagement in a redirected activation assay independent of stimulation via their invariant TCR. NKT cells killed P815 cells coated with anti-NKG2D mAb and CD1d-negative K562 tumor target cells in an NKG2D-dependent manner. Furthermore, NKG2D engagement co-stimulated TCR-mediated NKT-cell activation in response to endogenous CD1d-presented ligands or suboptimal levels of anti-CD3 triggering. These data indicate that the CD4- subset of human NKT cells can mediate direct lysis of target cells via NKG2D engagement independent of CD1d, and that NKG2D also functions as a co-stimulatory receptor in these cells. NKG2D thus plays both a direct and a co-stimulatory role in the activation of NKT cells. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crop responses to CO2 enrichment

International Nuclear Information System (INIS)

Rogers, H.H.; Dahlman, R.C.

1993-01-01

Carbon dioxide is rising in the global atmosphere, and this increase can be expected to continue into the foreseeable future. This compound is an essential input to plant life. Crop function is affected across all scales from biochemical to agroecosystem. An array of methods (leaf cuvettes, field chambers, free-air release systems) are available for experimental studies of CO 2 effects. Carbon dioxide enrichment of the air in which crops grow usually stimulates their growth and yield. Plant structure and physiology are markedly altered. Interactions between CO 2 and environmental factors that influence plants are known to occur. Implications for crop growth and yield are enormous. Strategies designed to assure future global food security must include a consideration of crop responses to elevated atmospheric CO 2 . 137 refs., 4 figs., 4 tabs

Forest productivity under elevated CO2 and O3: positive feedbacks to soil N cycling sustain decade-long net primary productivity enhancement by CO2

Science.gov (United States)

Donald R. Zak; Kurt S. Pregitzer; Mark E. Kubiske; Andrew J. Burton

2011-01-01

The accumulation of anthropogenic CO2 in the Earth's atmosphere, and hence the rate of climate warming, is sensitive to stimulation of plant growth by higher concentrations of atmospheric CO2. Here, we synthesise data from a field experiment in which three developing northern forest communities have been exposed to...

Root length, biomass, tissue chemistry and mycorrhizal colonization following 14 years of CO2 enrichment and 6 years of N fertilization in a warm temperate forest.

Science.gov (United States)

Taylor, Benton N; Strand, Allan E; Cooper, Emily R; Beidler, Katilyn V; Schönholz, Marcos; Pritchard, Seth G

2014-09-01

Root systems serve important roles in carbon (C) storage and resource acquisition required for the increased photosynthesis expected in CO2-enriched atmospheres. For these reasons, understanding the changes in size, distribution and tissue chemistry of roots is central to predicting the ability of forests to capture anthropogenic CO2. We sampled 8000 cm(3) soil monoliths in a pine forest exposed to 14 years of free-air-CO2-enrichment and 6 years of nitrogen (N) fertilization to determine changes in root length, biomass, tissue C : N and mycorrhizal colonization. CO2 fumigation led to greater root length (98%) in unfertilized plots, but root biomass increases under elevated CO2 were only found for roots biomass in N-fertilized plots (19%), but fine root [N] and [C] both increased under N fertilization (29 and 2%, respectively). Mycorrhizal root tip biomass responded positively to CO2 fumigation in unfertilized plots, but was unaffected by CO2 under N fertilization. Changes in fine root [N] and [C] call for further study of the effects of N fertilization on fine root function. Here, we show that the stimulation of pine roots by elevated CO2 persisted after 14 years of fumigation, and that trees did not rely exclusively on increased mycorrhizal associations to acquire greater amounts of required N in CO2-enriched plots. Stimulation of root systems by CO2 enrichment was seen primarily for fine root length rather than biomass. This observation indicates that studies measuring only biomass might overlook shifts in root systems that better reflect treatment effects on the potential for soil resource uptake. These results suggest an increase in fine root exploration as a primary means for acquiring additional soil resources under elevated CO2. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Slight changes in the mechanical stimulation affects osteoblast- and osteoclast-like cells in co-culture.

Science.gov (United States)

Kadow-Romacker, Anke; Duda, Georg N; Bormann, Nicole; Schmidmaier, Gerhard; Wildemann, Britt

2013-12-01

Osteoblast- and osteoclast-like cells are responsible for coordinated bone maintenance, illustrated by a balanced formation and resorption. Both parameters appear to be influenced by mechanical constrains acting on each of these cell types individually. We hypothesized that the interactions between both cell types are also influenced by mechanical stimulation. Co-cultures of osteoblast- and osteoclast-like cells were stimulated with 1,100 µstrain, 0.1 or 0.3 Hz for 1-5 min/day over 5 days. Two different setups depending on the differentiation of the osteoclast-like cells were used: i) differentiation assay for the fusion of pre-osteoclasts to osteoclasts, ii) resorption assay to determine the activity level of osteoclast-like cells. In the differentiation assay (co-culture of osteoblasts with unfused osteoclast precursor cells) the mechanical stimulation resulted in a significant decrease of collagen-1 and osteocalcin produced by osteoblast-like cells. Significantly more TRAP-iso5b was measured after stimulation for 3 min with 0.1 Hz, indicating enhanced osteoclastogenesis. In the resorption assay (co-culture of osteoblasts with fused osteoclasts) the stimulation for 3 min with 0.3 Hz significantly increased the resorption activity of osteoclasts measured by the pit formation and the collagen resorption. The same mechanical stimulation resulted in an increased collagen-1 production by the osteoblast-like cells. The ratio of RANKL/OPG was not different between the groups. These findings demonstrate that already small changes in duration or frequency of mechanical stimulation had significant consequences for the behavior of osteoblast- and osteoclast-like cells in co-culture, which partially depend on the differentiation status of the osteoclast-like cells.

Shifting of infrared radiation using rotational raman resonances in diatomic molecular gases

Science.gov (United States)

Kurnit, Norman A.

1980-01-01

A device for shifting the frequency of infrared radiation from a CO.sub.2 laser by stimulated Raman scattering in either H.sub.2 or D.sub.2. The device of the preferred embodiment comprises an H.sub.2 Raman laser having dichroic mirrors which are reflective for 16 .mu.m radiation and transmittive for 10 .mu.m, disposed at opposite ends of an interaction cell. The interaction cell contains a diatomic molecular gas, e.g., H.sub.2, D.sub.2, T.sub.2, HD, HT, DT and a capillary waveguide disposed within the cell. A liquid nitrogen jacket is provided around the capillary waveguide for the purpose of cooling. In another embodiment the input CO.sub.2 radiation is circularly polarized using a Fresnel rhomb .lambda./4 plate and applied to an interaction cell of much longer length for single pass operation.

Pre-Combustion Capture of CO2 in IGCC Plants

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-12-15

Pre-combustion capture involves reacting a fuel with oxygen or air and/or steam to give mainly a 'synthesis gas (syngas)' or 'fuel gas' composed of carbon monoxide and hydrogen. The carbon monoxide is reacted with steam in a catalytic reactor, called a shift converter, to produce CO2 and more hydrogen. CO2 is then separated, usually by a physical or chemical absorption process, resulting in a hydrogen-rich fuel which can be used in many applications, such as boilers, furnaces, gas turbines, engines and fuel cells. Pre-combustion capture is suitable for use in integrated gasification combined cycle (IGCC) plants especially since the CO2 partial pressures in the fuel gas are higher than in the flue gas. After the introduction there follows a short discussion of the water-gas shift (WGS) reaction. This is followed by chapters on the means of CO2 capture by physical and chemical solvents, solid sorbents, and membranes. The results and conclusions of techno-economic studies are introduced followed by a look at some of the pilot and demonstration plants relevant to pre-combustion capture in IGCC plants.

Synthesis of Hydrocarbons from H2-Deficient Syngas in Fischer-Tropsch Synthesis over Co-Based Catalyst Coupled with Fe-Based Catalyst as Water-Gas Shift Reaction

Directory of Open Access Journals (Sweden)

Ting Ma

2015-01-01

Full Text Available The effects of metal species in an Fe-based catalyst on structural properties were investigated through the synthesis of Fe-based catalysts containing various metal species such, as Mn, Zr, and Ce. The addition of the metal species to the Fe-based catalyst resulted in high dispersions of the Fe species and high surface areas due to the formation of mesoporous voids about 2–4 nm surrounded by the catalyst particles. The metal-added Fe-based catalysts were employed together with Co-loaded beta zeolite for the synthesis of hydrocarbons from syngas with a lower H2/CO ratio of 1 than the stoichiometric H2/CO ratio of 2 for the Fischer-Tropsch synthesis (FTS. Among the catalysts, the Mn-added Fe-based catalyst exhibited a high activity for the water-gas shift (WGS reaction with a comparative durability, leading to the enhancement of the CO hydrogenation in the FTS in comparison with Co-loaded beta zeolite alone. Furthermore, the loading of Pd on the Mn-added Fe-based catalyst enhanced the catalytic durability due to the hydrogenation of carbonaceous species by the hydrogen activated over Pd.

Stimulated Respiration and Net Photosynthesis in Cassiopeia sp. during Glucose Enrichment Suggests in hospite CO2 Limitation of Algal Endosymbionts

KAUST Repository

Radecker, Nils; Pogoreutz, Claudia; Wild, Christian; Voolstra, Christian R.

2017-01-01

such as corals is CO -limited. Here we show that glucose enrichment stimulates respiration and gross photosynthesis rates by 80 and 140%, respectively, in the symbiotic upside-down jellyfish Cassiopeia sp. from the Central Red Sea. Our findings show that glucose

Synchrotron radiation stimulated etching of SiO sub 2 thin films with a Co contact mask for the area-selective deposition of self-assembled monolayer

CERN Document Server

Wang, C

2003-01-01

The area-selective deposition of a self-assembled monolayer (SAM) was demonstrated on a pattern structure fabricated by synchrotron radiation (SR) stimulated etching of a SiO sub 2 thin film on the Si substrate. The etching was conducted by irradiating the SiO sub 2 thin film with SR through a Co contact mask and using a mixture of SF sub 6 + O sub 2 as the reaction gas. The SR etching stopped completely at the SiO sub 2 /Si interface. After the SR etching, the Si surface and the SiO sub 2 surface beneath the Co mask were evaluated by an atomic force microscope (AFM). A dodecene SAM was deposited on the Si surface, and trichlorosilane-derived SAMs (octadecyltrichlorosilane, and octenyltrichlorosilane) were deposited on the SiO sub 2 surface beneath the Co mask. The structure of the deposited SAMs showed a densely packed and well-ordered molecular architecture, which was characterized by infrared spectroscopy, ellipsometry, and water contact angle (WCA) measurements. (author)

Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage

Energy Technology Data Exchange (ETDEWEB)

Mahesh Iyer; Shwetha Ramkumar; Liang-Shih Fan

2006-09-30

Enhancement in the production of high purity hydrogen from fuel gas, obtained from coal gasification, is limited by thermodynamics of the Water Gas Shift Reaction. However, this constraint can be overcome by concurrent water-gas shift (WGS) and carbonation reactions to enhance H{sub 2} production by incessantly driving the equilibrium-limited WGS reaction forward and in-situ removing the CO2 product from the gas mixture. The spent sorbent is then regenerated by calcining it to produce a pure stream of CO{sub 2} and CaO which can be reused. However while performing the cyclic carbonation and calcination it was observed that the CO{sub 2} released during the in-situ calcination causes the deactivation of the iron oxide WGS catalyst. Detailed understanding of the iron oxide phase diagram helped in developing a catalyst pretreatment procedure using a H{sub 2}/H{sub 2}O system to convert the deactivated catalyst back to its active magnetite (Fe{sub 3}O{sub 4}) form. The water gas shift reaction was studied at different temperatures, different steam to carbon monoxide ratios (S/C) 3:1, 2:1, 1:1 and different total pressures ranging from 0-300 psig. The combined water gas shift and carbonation reaction was investigated at temperatures ranging from 600-700C, S/C ratio of 3:1 to 1:1 and at different pressures of 0-300 psig and the calcium looping process was found to produce high purity hydrogen with in-situ CO{sub 2} capture.

Night shift work characteristics and occupational co-exposures in industrial plants in Łódź, Poland

Directory of Open Access Journals (Sweden)

Beata Pepłońska

2013-08-01

Full Text Available Objectives: Night shift work involving circadian rhythm disruption has been classified by IARC as a probably carcinogenic to humans (Group 2A. Little is known about co-exposures of the night shift work in occupational settings. The aim of our study was to characterize night shift work systems and industrial exposures occurring in the manufacturing plants in Łódź, Poland, where night shift work system operates, with particular focus on potential carcinogens. Material and Methods: Data on the night shift work systems and hazardous agents were collected through survey performed in 44 enterprises. The identified hazardous agents were checked using the IARC carcinogen list, and the harmonized EU classification of chemical substances. We also examined databases of the Central Register of Data on exposure to substances, preparations, agents and technological processes showing carcinogenic or mutagenic properties in Poland. Results: The most common system of work among studied enterprises employed 3 (8-hour shifts within a 5-day cycle. We identified as many as 153 hazards occurring in the environment of the plants, with noise, carbon monoxide and formaldehyde recorded as the most common ones. Out of these hazards, 11 agents have been classified by IARC to group 1 - carcinogenic to humans, whereas 10 agents have been classified as carcino - gens by the regulation of European Classification of carcinogens. Analysis of the data from the Central Register revealed that 6 plants reported presence of carcinogens in the environment of work. Conclusions: In our study we observed that in none of the workplaces the night shift work was a single exposure. Further epidemiological studies focusing on investigation of health effects of the night shift work should identify occupational co -exposures and examine them as potential confounders.

Soil warming enhances the hidden shift of elemental stoichiometry by elevated CO2 in wheat

DEFF Research Database (Denmark)

Li, Xiangnan; Jiang, Dong; Liu, Fulai

2016-01-01

sap and their partitioning in different organs of wheat plant during grain filling were investigated. Results showed that the combination of elevated [CO2] and soil warming improved wheat grain yield, but decreased plant K, Ca and Mg accumulation and their concentrations in the leaves, stems, roots......Increase in atmospheric CO2 concentration ([CO2]) and associated soil warming along with global climate change are expected to have large impacts on grain mineral nutrition in wheat. The effects of CO2 elevation (700 μmol l(-1)) and soil warming (+2.4 °C) on K, Ca and Mg concentrations in the xylem...... and grains. The reduced grain mineral concentration was attributed to the lowered mineral uptake as exemplified by both the decreased stomatal conductance and mineral concentration in the xylem sap. These findings suggest that future higher atmospheric [CO2] and warmer soil conditions may decrease...

CO2-refrigeration. Investment in an energy efficient supermarket; CO2-koeling. Investeren in een energiezuinige supermarkt

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-11-15

Modem entrepreneurs invest in an energy-neutral supermarket. By that they are working on corporate social responsibility, sustainability and a green image of their company. The reduction of energy consumption results in an indirect reduction of CO2 emission by electric power stations. That is why more and more transcritical refrigeration plants with the natural refrigerant CO2, with global warming impact of 1, will be applied. The energy investment deduction scheme EIA, executed by NL Agency, stimulates a large number of energy saving measures which result in a financial profit for the investing owner or manager. [Dutch] Moderne ondememers investeren in een energieneutrale supermarkt. Ze zijn immers bezig met maatschappelijk verantwoord ondememen, verduurzaming en een groene uitstraling van hun bedrijf. Het terugdringen van het energiegebruik reduceert de indirecte CO2-uitstoot bij de elektriciteitscentrale aanzienlijk. Daarom worden steeds meer transkritische koel-vriesinstallaties die werken met het natuurlijke koudemiddel CO2, met een GWP-waarde van 1, toegepast. De Energie-investeringsaftrekregeling EIA, uitgevoerd door Agentschap NL, stimuleert een groot aantal energiebesparende maatregelen die ten goede komen aan de eigenaar of beheerder.

Syngas Production from CO2 Reforming and CO2-steam Reforming of Methane over Ni/Ce-SBA-15 Catalyst

Science.gov (United States)

Tan, J. S.; Danh, H. T.; Singh, S.; Truong, Q. D.; Setiabudi, H. D.; Vo, D.-V. N.

2017-06-01

This study compares the catalytic performance of mesoporous 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane reactions in syngas production. The catalytic performance of 10 Ni/Ce-SBA-15 catalyst for CO2 reforming and CO2-steam reforming of methane was evaluated in a temperature-controlled tubular fixed-bed reactor at stoichiometric feed composition, 1023 K and atmospheric pressure for 12 h on-stream with gas hourly space velocity (GHSV) of 36 L gcat -1 h-1. The 10 Ni/Ce-SBA-15 catalyst possessed a high specific BET surface area and average pore volume of 595.04 m2 g-1. The XRD measurement revealed the presence of NiO phase with crystallite dimension of about 13.60 nm whilst H2-TPR result indicates that NiO phase was completely reduced to metallic Ni0 phase at temperature beyond 800 K and the reduction temperature relied on different degrees of metal-support interaction associated with the location and size of NiO particles. The catalytic reactivity was significantly enhanced with increasing H2O/CO2 feed ratio. Interestingly, the H2/CO ratio for CO2-steam reforming of methane varied between 1 and 3 indicated the occurrence of parallel reactions, i.e., CH4 steam reforming giving a H2/CO of 3 whilst reverse water-gas shift (RWGS) reaction consuming H2 to produce CO gaseous product.

Metallic oxides supported in CeO{sub 2} and CeO{sub 2}-La{sub 2} O{sub 3} for low temperature shift reaction; Oxidos metalicos suportados em CeO{sub 2} e CeO{sub 2}-La{sub 2} O{sub 3} para reacao shift a baixa temperatura

Energy Technology Data Exchange (ETDEWEB)

Maluf, Silvia Salua; Assaf, Elisabete Moreira [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: sil_maluf@iqsc.usp.br

2008-07-01

This work studied copper and zinc oxides supported in CeO{sub 2} and CeO{sub 2}/La{sub 2}O{sub 3}. The catalytic tests for low temperature shift reaction, carried out for samples, showed the Cu-Ce catalyst presents the highest value of CO conversion (50%) and after the Cu-Ce-La catalysts (30%). The other catalysts showed CO conversion in range of 15%. This behavior is related with surface area, and also with the amount of Cu in the surface of samples (author)

A stimulation of an alternative photorespiratory CO2 pathway by ...

African Journals Online (AJOL)

... these responses to nitrogen, suggesting that the observed responses of T. triandra to nitrogen could in part account for its sensitivity to nitrogen inhibition of growth. Keywords: botany; co2; infiltration; inhibition; inhibitors; inorganic nitrogen; leaves; nitrogen; nitrogen levels; photosynthetic rate; plant physiology; productivity; ...

Impact of renewables deployment on the CO2 price and the CO2 emissions in the European electricity sector

International Nuclear Information System (INIS)

Van den Bergh, Kenneth; Delarue, Erik; D'haeseleer, William

2013-01-01

As of 2005, electricity generators in Europe operate under the European Union Emission Trading System (EU ETS). At the same time, European Member States have launched support mechanisms to stimulate the deployment of renewable electricity sources (RES-E). RES-E injections displace CO 2 emissions within the sectors operating under the EU ETS and they reduce the demand for European Union Allowances (EUAs), thereby reducing the EUA price. This paper presents the results of an ex post analysis to quantify the impact of RES-E deployment on the EUA price and CO 2 emissions in the Western and Southern European electricity sector during the period from 2007 to 2010, following from an operational partial equilibrium model of the electricity sector. This study shows that the CO 2 displacement from the electricity sector to other ETS sectors due to RES-E deployment can be up to more than 10% of historical CO 2 emissions in the electricity sector. The EUA price decrease caused by RES-E deployment turns out to be likely significant. - Author-Highlights: • We assessed the impact of renewables deployment in the period 2007–2010. • Impact on CO 2 emissions in the electricity sector and the CO 2 price is considered. • CO 2 emissions decreased by up to 10% of historical emissions. • CO 2 price decrease due to renewables turns out to be likely significant

When CO2 kills: effects of magmatic CO2 flux on belowground biota at Mammoth Mountain, CA

Science.gov (United States)

McFarland, J.; Waldrop, M. P.; Mangan, M.

2011-12-01

The biomass, composition, and activity of the soil microbial community is tightly linked to the composition of the aboveground plant community. Microorganisms in aerobic surface soils, both free-living and plant-associated are largely structured by the availability of growth limiting carbon (C) substrates derived from plant inputs. When C availability declines following a catastrophic event such as the death of large swaths of trees, the number and composition of microorganisms in soil would be expected to decline and/or shift to unique microorganisms that have better survival strategies under starvation conditions. High concentrations of volcanic cold CO2 emanating from Mammoth Mountain near Horseshoe Lake on the southwestern edge of Long Valley Caldera, CA has resulted in a large kill zone of tree species, and associated soil microbial species. In July 2010, we assessed belowground microbial community structure in response to disturbance of the plant community along a gradient of soil CO2 concentrations grading from 80% (no plant life). We employed a microbial community fingerprinting technique (automated ribosomal intergenic spacer analysis) to determine changes in overall community composition for three broad functional groups: fungi, bacteria, and archaea. To evaluate changes in ectomycorrhizal fungal associates along the CO2 gradient, we harvested root tips from lodgepole pine seedlings collected in unaffected forest as well as at the leading edge of colonization into the kill zone. We also measured soil C fractions (dissolved organic C, microbial biomass C, and non-extractable C) at 10 and 30 cm depth, as well as NH4+. Not surprisingly, our results indicate a precipitous decline in soil C, and microbial C with increasing soil CO2; phospholipid fatty acid analysis in conjunction with community fingerprinting indicate both a loss of fungal diversity as well as a dramatic decrease in biomass as one proceeds further into the kill zone. This observation was

Climate and domestic projects CO{sub 2}: why and how?; Climat et projets domestiques CO{sub 2}: pourquoi et comment?

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

In order to fight against the climatic change, the France decided to divide by four the greenhouse gases for 2050. With the emission trading, the industrialists and the energy producers progress in this way. But nothing is existing for the emission sectors as the transport, the agriculture, the building and for the greenhouse gases except the CO{sub 2}. The domestic projects CO{sub 2} approach aims to stimulate the realization of projects reducing the greenhouse gases emissions in these sectors, with a remuneration of these reductions. (A.L.B.)

Ectomycorrhizal colonization and growth of the hybrid larch F1 under elevated CO2 and O3

International Nuclear Information System (INIS)

Wang, Xiaona; Qu, Laiye; Mao, Qiaozhi; Watanabe, Makoto; Hoshika, Yasutomo; Koyama, Akihiro; Kawaguchi, Korin; Tamai, Yutaka; Koike, Takayoshi

2015-01-01

We studied the colonization of ectomycorrhizal fungi and species abundance of a hybrid larch (F 1 ) under elevated CO 2 and O 3. Two-year-old seedlings were planted in an Open-Top-Chamber system with treatments: Control (O 3  < 6 nmol/mol), O 3 (60 nmol/mol), CO 2 (600 μmol/mol), and CO 2  + O 3 . After two growing seasons, ectomycorrhiza (ECM) colonization and root biomass increased under elevated CO 2 . Additionally, O 3 impaired ECM colonization and species richness, and reduced stem biomass. However, there was no clear inhibition of photosynthetic capacity by O 3 . Concentrations of Al, Fe, Mo, and P in needles were reduced by O 3 , while K and Mg in the roots increased. This might explain the distinct change in ECM colonization rate and diversity. No effects of combined fumigation were observed in any parameters except the P concentration in needles. The tolerance of F 1 to O 3 might potentially be related to a shift in ECM community structure. - Highlights: • Elevated CO 2 enhanced growth of hybrid larch F 1 (F 1 ). • ECM colonization rate and species richness of ECM were reduced by O 3 . • Species abundance of ECM community differed between O 3 and control. • F 1 potentially resisted O 3 impacts via specific selection of Suillus spp. for element uptake. - Elevated CO 2 moderated the negative effects of O 3 on the growth of hybrid larch F 1 , by stimulating ectomycorrhizas and nutrient uptake

A stimulation of an alternative photorespiratory CO2 pathway by ...

African Journals Online (AJOL)

Vacuum infiltration of inorganic nitrogen ions affected the photosynthetic rate and CO2 compensation point of Themeda triandra and Zea mays in a similar way. However these two plants differed markedly in their photorespiratory mechanisms in response to inorganic nitrogen. Increased nitrogen levels in the in vitro reaction ...

Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation

Directory of Open Access Journals (Sweden)

Arendt-Nielsen Lars

2010-11-01

Full Text Available Abstract Background CO2 lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial to deeper skin layers. Methods In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO2 laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were compared to the subjective pain intensity ratings from 16 subjects and to the surface skin temperature distributions measured by an infrared camera. Results The stimulations were sensed significantly slower and less intense in glabrous skin than they were in hairy skin (MANOVA, p 0.90, p 2 (5 W, 0.12 s, d1/e2 = 11.4 mm only two reported pain to glabrous skin stimulation using the same stimulus intensity. The temperature at the epidermal-dermal junction (depth 50 μm in hairy and depth 133 μm in glabrous skin was estimated to 46°C for hairy skin stimulation and 39°C for glabrous skin stimulation. Conclusions As compared to previous one dimensional heat distribution models, the current two dimensional model provides new possibilities for detailed studies regarding CO2 laser stimulation intensity, temperature levels and nociceptor activation.

Soil warming enhances the hidden shift of elemental stoichiometry by elevated CO2 in wheat.

Science.gov (United States)

Li, Xiangnan; Jiang, Dong; Liu, Fulai

2016-03-22

Increase in atmospheric CO2 concentration ([CO2]) and associated soil warming along with global climate change are expected to have large impacts on grain mineral nutrition in wheat. The effects of CO2 elevation (700 μmol l(-1)) and soil warming (+2.4 °C) on K, Ca and Mg concentrations in the xylem sap and their partitioning in different organs of wheat plant during grain filling were investigated. Results showed that the combination of elevated [CO2] and soil warming improved wheat grain yield, but decreased plant K, Ca and Mg accumulation and their concentrations in the leaves, stems, roots and grains. The reduced grain mineral concentration was attributed to the lowered mineral uptake as exemplified by both the decreased stomatal conductance and mineral concentration in the xylem sap. These findings suggest that future higher atmospheric [CO2] and warmer soil conditions may decrease the dietary availability of minerals from wheat crops. Breeding wheat cultivars possessing higher ability of mineral uptake at reduced xylem flux in exposure to climate change should be a target.

Coral reefs - sources or sinks of atmospheric CO[sub 2

Energy Technology Data Exchange (ETDEWEB)

Ware, J R; Smith, S V; Reakakudla, M L [Hawaii University, Honolulu, HI (USA). Dept. of Oceanography

1992-09-01

Because the precipitation of calcium carbonate results in the sequestering of carbon, it frequently has been thought that coral reefs function as sinks of global atmospheric CO[sub 2]. However, the precipitation of calcium carbonate is accompanied by a shift of pH that results in the release of CO[sub 2]. This release of CO[sub 2] is less in buffered sea water than fresh water systems; nevertheless, coral reefs are sources, not sinks, of atmospheric carbon. Using estimated rates of coral reef carbonate production, we compute that coral reefs release 0.02 to 0.08 Gt C as CO[sub 2] annually. This is approximately 0.4% to 1.4% of the current anthropogenic CO[sub 2] production due to fossil fuel combustion.

NMR study of Gd2(Co1-xFex)14B compounds

International Nuclear Information System (INIS)

Hayashi, M.; Myojin, T.; Kasamatsu, Y.; Imaeda, Y.; Ushida, T.; Tsujimura, A.; Hihara, T.

1992-01-01

59 Co NMR measurements in Gd 2 (Co 1-x Fe x ) 14 B have been carried out at 4.2 K. The resonance line corresponding to each site of the Co atoms shifts gradually to a higher frequency region as the value of x increases, and when the value exceeds 0.3 the resonance line seems to be disturbed. (orig.)

Elevated CO2-mitigation of high temperature stress associated with maintenance of positive carbon balance and carbohydrate accumulation in Kentucky bluegrass.

Science.gov (United States)

Song, Yali; Yu, Jingjin; Huang, Bingru

2014-01-01

Elevated CO2 concentration may promote plant growth while high temperature is inhibitory for C3 plant species. The interactive effects of elevated CO2 and high temperatures on C3 perennial grass growth and carbon metabolism are not well documented. Kentucky bluegrass (Poa pratensis) plants were exposed to two CO2 levels (400 and 800 μmol mol-1) and five temperatures (15/12, 20/17, 25/22, 30/27, 35/32°C, day/night) in growth chambers. Increasing temperatures to 25°C and above inhibited leaf photosynthetic rate (Pn) and shoot and root growth, but increased leaf respiration rate (R), leading to a negative carbon balance and a decline in soluble sugar content under ambient CO2. Elevated CO2 did not cause shift of optimal temperatures in Kentucky bluegrass, but promoted Pn, shoot and root growth under all levels of temperature (15, 20, 25, 30, and 35°C) and mitigated the adverse effects of severe high temperatures (30 and 35°C). Elevated CO2-mitigation of adverse effects of high temperatures on Kentucky bluegrass growth could be associated with the maintenance of a positive carbon balance and the accumulation of soluble sugars and total nonstructural carbohydrates through stimulation of Pn and suppression of R and respiratory organic acid metabolism.

CO2 induced climatic change and spectral variations in the outgoing terrestrial infrared radiation

Science.gov (United States)

Charlock, T. P.

1984-01-01

The published temperature changes produced in general circulation model simulations of CO2 induced climate modification are used to compute the top of the atmosphere, clear sky outgoing infrared radiance changes expected for doubled CO2. A significant wavenumber shift is produced, with less radiance emerging in the 500-800 per cm (20.0-12.5 micron) CO2 band and with more emerging in the 800-1200 per cm (12.5-8.3 micron) window. The effect varies greatly with latitude. The radiance shift in the 2300 per cm (4.3 micron) region is of the order of 10-30 percent for doubled CO2. It is suggested that the 2300 per cm region be carefully monitored as an aid in detecting the climatic effects of increasing CO2. The change in the wavenumber-integrated radiant exitance is at most a few percent.

Response of archaeal communities in the rhizosphere of maize and soybean to elevated atmospheric CO2 concentrations.

Directory of Open Access Journals (Sweden)

David M Nelson

Full Text Available BACKGROUND: Archaea are important to the carbon and nitrogen cycles, but it remains uncertain how rising atmospheric carbon dioxide concentrations ([CO(2] will influence the structure and function of soil archaeal communities. METHODOLOGY/PRINCIPAL FINDINGS: We measured abundances of archaeal and bacterial 16S rRNA and amoA genes, phylogenies of archaeal 16S rRNA and amoA genes, concentrations of KCl-extractable soil ammonium and nitrite, and potential ammonia oxidation rates in rhizosphere soil samples from maize and soybean exposed to ambient (∼385 ppm and elevated (550 ppm [CO(2] in a replicated and field-based study. There was no influence of elevated [CO(2] on copy numbers of archaeal or bacterial 16S rRNA or amoA genes, archaeal community composition, KCl-extractable soil ammonium or nitrite, or potential ammonia oxidation rates for samples from maize, a model C(4 plant. Phylogenetic evidence indicated decreased relative abundance of crenarchaeal sequences in the rhizosphere of soybean, a model leguminous-C(3 plant, at elevated [CO(2], whereas quantitative PCR data indicated no changes in the absolute abundance of archaea. There were no changes in potential ammonia oxidation rates at elevated [CO(2] for soybean. Ammonia oxidation rates were lower in the rhizosphere of maize than soybean, likely because of lower soil pH and/or abundance of archaea. KCl-extractable ammonium and nitrite concentrations were lower at elevated than ambient [CO(2] for soybean. CONCLUSION: Plant-driven shifts in soil biogeochemical processes in response to elevated [CO(2] affected archaeal community composition, but not copy numbers of archaeal genes, in the rhizosphere of soybean. The lack of a treatment effect for maize is consistent with the fact that the photosynthesis and productivity of maize are not stimulated by elevated [CO(2] in the absence of drought.

CO2 reduction by dematerialization

Energy Technology Data Exchange (ETDEWEB)

Hekkert, M.P. [Department of Innovation Studies, Copernicus Institute, Utrecht University, Utrecht (Netherlands)

2002-04-01

Current policy for the reduction of greenhouse gases is mainly concerned with a number of types of solutions: energy saving, shifting to the use of low-carbon fuels and the implementation of sustainable energy technologies. Recent research has shown that a strategy directed at a more efficient use of materials could make a considerable contribution to reducing CO2 emissions. Moreover, the costs to society as a whole of such a measure appear to be very low.

An analysis of Chinas CO2 emission peaking target and pathways

OpenAIRE

He, Jian-Kun

2017-01-01

China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching target and a key point of action for Chinas resource conservation, environmental protection, shift in economic development patterns, and CO2 emission reduction to avoid climate change. The development stage where China maps out the CO2 emission peak target is earlier than that of the ...

Ocean acidification: the other CO2 problem.

Science.gov (United States)

Doney, Scott C; Fabry, Victoria J; Feely, Richard A; Kleypas, Joan A

2009-01-01

Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds. One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals. Many calcifying species exhibit reduced calcification and growth rates in laboratory experiments under high-CO2 conditions. Ocean acidification also causes an increase in carbon fixation rates in some photosynthetic organisms (both calcifying and noncalcifying). The potential for marine organisms to adapt to increasing CO2 and broader implications for ocean ecosystems are not well known; both are high priorities for future research. Although ocean pH has varied in the geological past, paleo-events may be only imperfect analogs to current conditions.

Effects of CO2 and temperature on growth and resource use of co-occurring C3 and C4 annuals

International Nuclear Information System (INIS)

Coleman, J.S.; Bazzaz, F.A.

1992-01-01

The authors examined how CO 2 concentrations and temperature interacted to affect growth, resource acquisition, and resource allocation of two annual plants that were supplied with a single pulse of nutrients. Physiological and growth measurements were made on individuals of Abutilon throphrasti (C 3 ) and Amaranthus retroflexus (C 4 ) grown in environments with atmospheric CO 2 levels of 400 or 700 μL/L and with light/dark temperatures of 28 degree/22 degree or 38 degree/31 degree C. Elevated CO 2 and temperature treatments had significant independent and interactive effects on plant growth, resource allocation, and resource acquisition, and the strength and direction of these effects were often dependent on plant species. For example, final biomass of Amaranthus was enhanced by elevated CO 2 at 28 degree but was depressed at 38 degree. For Abutilon, elevated CO 2 increased initial plant relative growth rates at 28 degree but not at 38 degree, and had no significant effects on final biomass at either temperature. These results are interpreted in light of the interactive effects of CO 2 and temperature on the rates of net leaf area production and loss, and on net whole-plant nitrogen retention. At 28 degree C, elevated CO 2 stimulated the initial production of leaf area in both species, which led to an initial stimulation of biomass accumulation at the higher CO 2 level. However, in elevated CO 2 at 28 degree, the rate of net leaf area loss for Abutilon increased while that of Amaranthus decreased. Furthermore, high CO 2 apparently enhanced the ability of Amaranthus to retain nitrogen at this temperature, which may have helped to enhance photosynthesis, whereas nitrogen retention was unaffected in Abutilon

Infrared Spectroscopy of Gas-Phase M+(CO2)n (M = Co, Rh, Ir) Ion-Molecule Complexes.

Science.gov (United States)

Iskra, Andreas; Gentleman, Alexander S; Kartouzian, Aras; Kent, Michael J; Sharp, Alastair P; Mackenzie, Stuart R

2017-01-12

The structures of gas-phase M + (CO 2 ) n (M = Co, Rh, Ir; n = 2-15) ion-molecule complexes have been investigated using a combination of infrared resonance-enhanced photodissociation (IR-REPD) spectroscopy and density functional theory. The results provide insight into fundamental metal ion-CO 2 interactions, highlighting the trends with increasing ligand number and with different group 9 ions. Spectra have been recorded in the region of the CO 2 asymmetric stretch around 2350 cm -1 using the inert messenger technique and their interpretation has been aided by comparison with simulated infrared spectra of calculated low-energy isomeric structures. All vibrational bands in the smaller complexes are blue-shifted relative to the asymmetric stretch in free CO 2 , consistent with direct binding to the metal center dominated by charge-quadrupole interactions. For all three metal ions, a core [M + (CO 2 ) 2 ] structure is identified to which subsequent ligands are less strongly bound. No evidence is observed in this size regime for complete activation or insertion reactions.

Phase gradient algorithm based on co-axis two-step phase-shifting interferometry and its application

Science.gov (United States)

Wang, Yawei; Zhu, Qiong; Xu, Yuanyuan; Xin, Zhiduo; Liu, Jingye

2017-12-01

A phase gradient method based on co-axis two-step phase-shifting interferometry, is used to reveal the detailed information of a specimen. In this method, the phase gradient distribution can only be obtained by calculating both the first-order derivative and the radial Hilbert transformation of the intensity difference between two phase-shifted interferograms. The feasibility and accuracy of this method were fully verified by the simulation results for a polystyrene sphere and a red blood cell. The empirical results demonstrated that phase gradient is sensitive to changes in the refractive index and morphology. Because phase retrieval and tedious phase unwrapping are not required, the calculation speed is faster. In addition, co-axis interferometry has high spatial resolution.

Tropical epiphytes in a CO 2-rich atmosphere

Science.gov (United States)

Monteiro, José Alberto Fernandez; Zotz, Gerhard; Körner, Christian

2009-01-01

We tested the effect on epiphyte growth of a doubling of pre-industrial CO 2 concentration (280 vs. 560 ppm) combined with two light (three fold) and two nutrition (ten fold) treatments under close to natural humid conditions in daylight growth cabinets over 6 months. Across co-treatments and six species, elevated CO 2 increased relative growth rates by only 6% ( p = 0.03). Although the three C3 species, on average, grew 60% faster than the three CAM species, the two groups did not significantly differ in their CO 2 response. The two Orchidaceae, Bulbophyllum (CAM) and Oncidium (C3) showed no CO 2 response, and three out of four Bromeliaceae showed a positive one: Aechmea (CAM, +32% p = 0.08), Catopsis (C3, +11% p = 0.01) and Vriesea (C3, +4% p = 0.02). In contrast, the representative of the species-rich genus Tillandsia (CAM), which grew very well under experimental conditions, showed no stimulation. On average, high light increased growth by 21% and high nutrients by 10%. Interactions between CO 2, light and nutrient treatments (low vs. high) were inconsistent across species. CO 2 responsive taxa such as Catopsis, could accelerate tropical forest dynamics and increase branch breakage, but overall, the responses to doubling CO 2 of these epiphytes was relatively small and the responses were taxa specific.

NMR study of Y2(Co1-xFex)14B compounds

International Nuclear Information System (INIS)

Maruyama, F.; Ichinose, K.; Nagai, H.; Adachi, K.; Misawa, M.; Tsujimura, A.

1992-01-01

59 Co and 89 Y NMR of Y 2 (Co 1-x Fe x ) 14 B compounds has been measured at 4.2 K. The line positions shift rapidly to higher frequency for x≤0.3 and are almost constant for 0.3 1 and 8j 2 sites give a large contribution to the anisotropy of the 3d sublattice. (orig.)

Silvering substrates after CO2 snow cleaning

Science.gov (United States)

Zito, Richard R.

2005-09-01

There have been some questions in the astronomical community concerning the quality of silver coatings deposited on substrates that have been cleaned with carbon dioxide snow. These questions center around the possible existence of carbonate ions left behind on the substrate by CO2. Such carbonate ions could react with deposited silver to produce insoluble silver carbonate, thereby reducing film adhesion and reflectivity. Carbonate ions could be produced from CO2 via the following mechanism. First, during CO2 snow cleaning, a small amount of moisture can condense on a surface. This is especially true if the jet of CO2 is allowed to dwell on one spot. CO2 gas can dissolve in this moisture, producing carbonic acid, which can undergo two acid dissociations to form carbonate ions. In reality, it is highly unlikely that charged carbonate ions will remain stable on a substrate for very long. As condensed water evaporates, Le Chatelier's principle will shift the equilibrium of the chain of reactions that produced carbonate back to CO2 gas. Furthermore, the hydration of CO2 reaction of CO2 with H20) is an extremely slow process, and the total dehydrogenation of carbonic acid is not favored. Living tissues that must carry out the equilibration of carbonic acid and CO2 use the enzyme carbonic anhydrase to speed up the reaction by a factor of one million. But no such enzymatic action is present on a clean mirror substrate. In short, the worst case analysis presented below shows that the ratio of silver atoms to carbonate radicals must be at least 500 million to one. The results of chemical tests presented here support this view. Furthermore, film lift-off tests, also presented in this report, show that silver film adhesion to fused silica substrates is actually enhanced by CO2 snow cleaning.

Using Co-innovation to Stimulate Innovation in the New Zealand Agricultural Sector

NARCIS (Netherlands)

Botha, N.; Klerkx, L.W.A.; Small, B.; Turner, J.A.

2014-01-01

A recently implemented research and development program; Co-learning and Coinnovation to Achieve Impact in New Zealand’s Biological Industries (Primary Innovation for short) aims to stimulate innovation in the New Zealand agricultural sector, which is an important contributor to the New Zealand

Co-culture with infrapatellar fat pad differentially stimulates proteoglycan synthesis and accumulation in cartilage and meniscus tissues.

Science.gov (United States)

Nishimuta, James F; Bendernagel, Monica F; Levenston, Marc E

2017-09-01

Although osteoarthritis is widely viewed as a disease of the whole joint, relatively few studies have focused on interactions among joint tissues in joint homeostasis and degeneration. In particular, few studies have examined the effects of the infrapatellar fat pad (IFP) on cartilaginous tissues. The aim of this study was to test the hypothesis that co-culture with healthy IFP would induce degradation of cartilage and meniscus tissues. Bovine articular cartilage, meniscus, and IFP were cultured isolated or as cartilage-fat or meniscus-fat co-cultures for up to 14 days. Conditioned media were assayed for sulfated glycosaminoglycan (sGAG) content, nitrite content, and matrix metalloproteinase (MMP) activity, and explants were assayed for sGAG and DNA contents. Co-cultures exhibited increased cumulative sGAG release and sGAG release rates for both cartilage and meniscus, and the cartilage (but not meniscus) exhibited a substantial synergistic effect of co-culture (sGAG release in co-culture was significantly greater than the summed release from isolated cartilage and fat). Fat co-culture did not significantly alter the sGAG content of either cartilage or meniscus explants, indicating that IFP co-culture stimulated net sGAG production by cartilage. Nitrite release was increased relative to isolated tissue controls in co-cultured meniscus, but not the cartilage, with no synergistic effect of co-culture. Interestingly, MMP-2 production was decreased by co-culture for both cartilage and meniscus. This study demonstrates that healthy IFP may modulate joint homeostasis by stimulating sGAG production in cartilage. Counter to our hypothesis, healthy IFP did not promote degradation of either cartilage or meniscus tissues.

Thermally and optically stimulated radiative processes in Eu and Y co-doped LiCaAlF6 crystal

International Nuclear Information System (INIS)

Fukuda, Kentaro; Yanagida, Takayuki; Fujimoto, Yutaka

2015-01-01

Yttrium co-doping was attempted to enhance dosimeter performance of Eu doped LiCaAlF 6 crystal. Eu doped and Eu, Y co-doped LiCaAlF 6 were prepared by the micro-pulling-down technique, and their dosimeter characteristics such as optically stimulated luminescence (OSL) and thermally stimulated luminescence (TSL) were investigated. By yttrium co-doping, emission intensities of OSL and TSL were enhanced by some orders of magnitude. In contrast, scintillation characteristics of yttrium co-doped crystal such as intensity of prompt luminescence induced by X-ray and light yield under neutron irradiation were degraded

Cyanobacterial carbon concentrating mechanisms facilitate sustained CO2 depletion in eutrophic lakes

Science.gov (United States)

Morales-Williams, Ana M.; Wanamaker, Alan D., Jr.; Downing, John A.

2017-06-01

Phytoplankton blooms are increasing in frequency, intensity, and duration in aquatic ecosystems worldwide. In many eutrophic lakes, these high levels of primary productivity correspond to periods of CO2 depletion in surface waters. Cyanobacteria and other groups of phytoplankton have the ability to actively transport bicarbonate (HCO3-) across their cell membrane when CO2 concentrations are limiting, possibly giving them a competitive advantage over algae not using carbon concentrating mechanisms (CCMs). To investigate whether CCMs can maintain phytoplankton bloom biomass under CO2 depletion, we measured the δ13C signatures of dissolved inorganic carbon (δ13CDIC) and phytoplankton particulate organic carbon (δ13Cphyto) in 16 mesotrophic to hypereutrophic lakes during the ice-free season of 2012. We used mass-balance relationships to determine the dominant inorganic carbon species used by phytoplankton under CO2 stress. We found a significant positive relationship between phytoplankton biomass and phytoplankton δ13C signatures as well as a significant nonlinear negative relationship between water column ρCO2 and isotopic composition of phytoplankton, indicating a shift from diffusive uptake to active uptake by phytoplankton of CO2 or HCO3- during blooms. Calculated photosynthetic fractionation factors indicated that this shift occurs specifically when surface water CO2 drops below atmospheric equilibrium. Our results indicate that active HCO3- uptake via CCMs may be an important mechanism in maintaining phytoplankton blooms when CO2 is depleted. Further increases in anthropogenic pressure, eutrophication, and cyanobacteria blooms are therefore expected to contribute to increased bicarbonate uptake to sustain primary production.

Cyanobacterial carbon concentrating mechanisms facilitate sustained CO2 depletion in eutrophic lakes

Directory of Open Access Journals (Sweden)

A. M. Morales-Williams

2017-06-01

Full Text Available Phytoplankton blooms are increasing in frequency, intensity, and duration in aquatic ecosystems worldwide. In many eutrophic lakes, these high levels of primary productivity correspond to periods of CO2 depletion in surface waters. Cyanobacteria and other groups of phytoplankton have the ability to actively transport bicarbonate (HCO3− across their cell membrane when CO2 concentrations are limiting, possibly giving them a competitive advantage over algae not using carbon concentrating mechanisms (CCMs. To investigate whether CCMs can maintain phytoplankton bloom biomass under CO2 depletion, we measured the δ13C signatures of dissolved inorganic carbon (δ13CDIC and phytoplankton particulate organic carbon (δ13Cphyto in 16 mesotrophic to hypereutrophic lakes during the ice-free season of 2012. We used mass–balance relationships to determine the dominant inorganic carbon species used by phytoplankton under CO2 stress. We found a significant positive relationship between phytoplankton biomass and phytoplankton δ13C signatures as well as a significant nonlinear negative relationship between water column ρCO2 and isotopic composition of phytoplankton, indicating a shift from diffusive uptake to active uptake by phytoplankton of CO2 or HCO3− during blooms. Calculated photosynthetic fractionation factors indicated that this shift occurs specifically when surface water CO2 drops below atmospheric equilibrium. Our results indicate that active HCO3− uptake via CCMs may be an important mechanism in maintaining phytoplankton blooms when CO2 is depleted. Further increases in anthropogenic pressure, eutrophication, and cyanobacteria blooms are therefore expected to contribute to increased bicarbonate uptake to sustain primary production.

The growth response of plants to elevated CO2 under non-optimal environmental conditions

NARCIS (Netherlands)

Poorter, H.; Pérez-Soba, M.

2001-01-01

Under benign environmental conditions, plant growth is generally stimulated by elevated atmospheric CO2 concentrations. When environmental conditions become sub- or supra-optimal for growth, changes in the biomass enhancement ratio (BER; total plant biomass at elevated CO2 divided by plant biomass

Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation

Science.gov (United States)

2010-01-01

Background CO2 lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial to deeper skin layers. Methods In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO2 laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were compared to the subjective pain intensity ratings from 16 subjects and to the surface skin temperature distributions measured by an infrared camera. Results The stimulations were sensed significantly slower and less intense in glabrous skin than they were in hairy skin (MANOVA, p 0.90, p < 0.001). Of the 16 subjects tested; eight subjects reported pricking pain in the hairy skin following a stimulus of 0.6 J/cm2 (5 W, 0.12 s, d1/e2 = 11.4 mm) only two reported pain to glabrous skin stimulation using the same stimulus intensity. The temperature at the epidermal-dermal junction (depth 50 μm in hairy and depth 133 μm in glabrous skin) was estimated to 46°C for hairy skin stimulation and 39°C for glabrous skin stimulation. Conclusions As compared to previous one dimensional heat distribution models, the current two dimensional model provides new possibilities for detailed studies regarding CO2 laser stimulation intensity, temperature levels and nociceptor activation. PMID:21059226

Carbon Dioxide (CO2 Sequestration In Bio-Concrete, An Overview

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Faisal Alshalif A.

2017-01-01

Full Text Available The emission of CO2 into atmosphere which has increased rapidly in the last years has led to global warming. Therefore, in order to overcome the negative impacts on human and environment, the researchers focused mainly on the reduction and stabilization of CO2 which represent the main contributor in the increasing global warming. The natural capturing and conversion of CO2 from atmosphere is taken place by biological, chemical and physical processes. However, these processes need long time to cause a significant reduction in CO2. Recently, scientists shifted to use green technologies that aimed to produce concrete with high potential to adsorb CO2 in order to accelerate the reduction of CO2. In the present review the potential of bio-concrete to sequestrate CO2 based on carbonation process and as a function of carbonic anhydrase (CA is highlighted. The factors affecting CO2 sequestration in concrete and bacterial species are discussed. It is evident from the literatures, that the new trends to use bio-concrete might contribute in the reduction of CO2 and enhance the strength of non-reinforced concrete.

Impact of elevated CO2 concentration on dynamics of leaf photosynthesis in Fagus sylvatica is modulated by sky conditions

International Nuclear Information System (INIS)

Urban, Otmar; Klem, Karel; Holišová, Petra; Šigut, Ladislav; Šprtová, Mirka; Teslová-Navrátilová, Petra; Zitová, Martina; Špunda, Vladimír; Marek, Michal V.; Grace, John

2014-01-01

It has been suggested that atmospheric CO 2 concentration and frequency of cloud cover will increase in future. It remains unclear, however, how elevated CO 2 influences photosynthesis under complex clear versus cloudy sky conditions. Accordingly, diurnal changes in photosynthetic responses among beech trees grown at ambient (AC) and doubled (EC) CO 2 concentrations were studied under contrasting sky conditions. EC stimulated the daily sum of fixed CO 2 and light use efficiency under clear sky. Meanwhile, both these parameters were reduced under cloudy sky as compared with AC treatment. Reduction in photosynthesis rate under cloudy sky was particularly associated with EC-stimulated, xanthophyll-dependent thermal dissipation of absorbed light energy. Under clear sky, a pronounced afternoon depression of CO 2 assimilation rate was found in sun-adapted leaves under EC compared with AC conditions. This was caused in particular by stomata closure mediated by vapour pressure deficit. -- Highlights: • Sky conditions affect the relative impact of elevated CO 2 on photosynthesis. • Cloudy skies reduce light use efficiency and carbon gain when CO 2 is elevated. • Stimulation of photosynthesis by high CO 2 may decline with increasing cloud cover. • High CO 2 leads to marked afternoon photosynthesis depression in sun-adapted leaves. -- The stimulatory effect of elevated CO 2 concentration on photosynthetic carbon assimilation can be expected to diminish as cloud cover increases

Water relations in grassland and desert ecosystems exposed to elevated atmospheric CO2.

Science.gov (United States)

Morgan, J A; Pataki, D E; Körner, C; Clark, H; Del Grosso, S J; Grünzweig, J M; Knapp, A K; Mosier, A R; Newton, P C D; Niklaus, P A; Nippert, J B; Nowak, R S; Parton, W J; Polley, H W; Shaw, M R

2004-06-01

Atmospheric CO2 enrichment may stimulate plant growth directly through (1) enhanced photosynthesis or indirectly, through (2) reduced plant water consumption and hence slower soil moisture depletion, or the combination of both. Herein we describe gas exchange, plant biomass and species responses of five native or semi-native temperate and Mediterranean grasslands and three semi-arid systems to CO2 enrichment, with an emphasis on water relations. Increasing CO2 led to decreased leaf conductance for water vapor, improved plant water status, altered seasonal evapotranspiration dynamics, and in most cases, periodic increases in soil water content. The extent, timing and duration of these responses varied among ecosystems, species and years. Across the grasslands of the Kansas tallgrass prairie, Colorado shortgrass steppe and Swiss calcareous grassland, increases in aboveground biomass from CO2 enrichment were relatively greater in dry years. In contrast, CO2-induced aboveground biomass increases in the Texas C3/C4 grassland and the New Zealand pasture seemed little or only marginally influenced by yearly variation in soil water, while plant growth in the Mojave Desert was stimulated by CO2 in a relatively wet year. Mediterranean grasslands sometimes failed to respond to CO2-related increased late-season water, whereas semiarid Negev grassland assemblages profited. Vegetative and reproductive responses to CO2 were highly varied among species and ecosystems, and did not generally follow any predictable pattern in regard to functional groups. Results suggest that the indirect effects of CO2 on plant and soil water relations may contribute substantially to experimentally induced CO2-effects, and also reflect local humidity conditions. For landscape scale predictions, this analysis calls for a clear distinction between biomass responses due to direct CO2 effects on photosynthesis and those indirect CO2 effects via soil moisture as documented here.

Trapping of CH4, CO, and CO2 in Amorphous Water Ice

Science.gov (United States)

Mastrapa, R. M. E.; Brown, R. H.; Anicich, V. G.; Cohen, B. A.; Dai, W.; Lunine, J. I.

1999-09-01

In this study, CO, CH4, and CO2 were trapped in H2O at temperatures as low as 20 K and pressures between 10-5 and 10-8 Torr. IR spectra were taken of each sample before sublimation to confirm the presence of volatiles. The samples were then heated at rates from 0.25 K/min to 1 K/min and the escape ranges were measured with a mass spectrometer. The volatiles escaped from the ice mixtures in temperature ranges similar to those found in previous work (1, 2, 3), namely 48-52 K, 145-160 K, 170-185 K. H2O is released from 150 K to 185 K. However, the temperature range of escape is strongly dependent on deposition temperature and heating rate. If the deposition temperature is below the point where the solid volatile rapidly sublimates in the ambient environment of our experiment, then the first range of volatile escape is centered around it's sublimation point, and there is little of the volatile remaining from 170-185 K. The location of the third escape range shifts to lower temperatures with slower sublimation rate. It was determined that 0.5 K/min is the ideal sample heating rate to determine these escape ranges. In our data, the infrared spectrum of CO trapped in water ice shows a splitting of the 2145 cm-1 solid CO line into two bands at 2343 cm-1 and 2135 cm-1. These shifts are similar to those seen by Sandford, et al. (4). (1) Bar-Nun, A., G. Herman, D. Laufer, and M. L. Rappaport, (1985), Icarus, 63, 317-332. (2) Bar-Nun, A., J. Dror, E. Kochavi, and D. Laufer, (1987), Physical Review B, 35, no. 5, 2427-2435. (3) Hudson, R. L., and B. Donn, (1991), Icarus, 94, 326-332. (4) Sandford, S. A., L. J. Allamandola, A. G. G. M. Tielens, and G. J. Valero, (1988), Astrophysical Journal, 329, 498-510.

Elevated CO{sub 2} levels and herbivore damage alter host plant preferences

Energy Technology Data Exchange (ETDEWEB)

Agrell, J. [Lund Univ., Dept. of Animal Ecology, Lund (Sweden); Anderson, Peter, Swedish Univ. of Agricultural Sciences, Dept. of Crop Sciences, Alnarp (SE)); Oleszek, W.; Stochmal, Anna [Inst. of Soil Science and Plant Cultivation, Dept. of Biochemistry, Pulawy (Poland); Agrell, Cecilia [Lund Univ., Dept. of Chemical Ecology and Ecotoxicology, Lund (Sweden)

2006-01-01

Interactions between the moth Spodoptera littoralis and two of its host plants, alfalfa (Medicago sativa) and cotton (Gossypium hirsutum) were examined, using plants grown under ambient (350 ppm) and elevated (700 ppm) CO{sub 2} conditions. To determine strength and effects of herbivore-induced responses assays were performed with both undamaged (control) and herbivore damaged plants. CO{sub 2} and damage effects on larval host plant preferences were determined through dual-choice bioassays. In addition, larvae were reared from hatching to pupation on experimental foliage to examine effects on larval growth and development. When undamaged plants were used S. littoralis larvae in consumed more cotton than alfalfa, and CO{sub 2} enrichment caused a reduction in the preference for cotton. With damaged plants larvae consumed equal amounts of the two plant species (ambient CO{sub 2} conditions), but CO{sub 2} enrichment strongly shifted preferences towards cotton, which was then consumed three times more than alfalfa. Complementary assays showed that elevated CO{sub 2} levels had no effect on the herbivore-induced responses of cotton, whereas those of alfalfa were significantly increased. Larval growth was highest for larvae fed undamaged cotton irrespectively of CO{sub 2} level, and lowest for larvae on damaged alfalfa from the high CO{sub 2} treatment. Development time increased on damaged cotton irrespectively of CO{sub 2} treatment, and on damaged alfalfa in the elevated CO{sub 2} treatment. (au) These results demonstrate that elevated CO2 levels can cause insect herbivores to alter host plant preferences, and that effects on herbivore-induced responses may be a key mechanism behind these processes. Furthermore, since the insects were shown to avoid foliage that reduced their physiological performance, our data suggest that behavioural host plant shifts result in partial escape from negative consequences of feeding on high CO2 foliage. Thus, CO2 enrichment can alter

Climate and domestic projects CO2: why and how?

International Nuclear Information System (INIS)

2006-01-01

In order to fight against the climatic change, the France decided to divide by four the greenhouse gases for 2050. With the emission trading, the industrialists and the energy producers progress in this way. But nothing is existing for the emission sectors as the transport, the agriculture, the building and for the greenhouse gases except the CO 2 . The domestic projects CO 2 approach aims to stimulate the realization of projects reducing the greenhouse gases emissions in these sectors, with a remuneration of these reductions. (A.L.B.)

Biomethanation Of Syngas Using Anaerobic Sludge: Shift In The Catabolic Routes With The CO Partial Pressure Increase

Directory of Open Access Journals (Sweden)

Silvia Sancho-Navarro

2016-08-01

Full Text Available Syngas generated by thermal gasification of biomass or coal can be steam reformed and purified into methane, which could be used locally for energy needs, or re-injected in the natural gas grid. As an alternative to chemical catalysis, the main components of the syngas (CO, CO2, and H2 can be used as substrates by a wide range of microorganisms, to be converted into gas biofuels, including methane. This study evaluates the carboxydotrophic (CO-consuming methanogenic potential present in an anaerobic sludge from an upflow anaerobic sludge bed (UASB reactor treating waste water, and elucidates the CO conversion routes to methane at 35±3˚C. Kinetic activity tests under CO at partial pressures (pCO varying from 0.1 to 1.5 atm (0.09-1.31 mmol/L in the liquid phase showed a significant carboxydotrophic activity potential for growing conditions on CO alone. A maximum methanogenic activity of 1 mmol CH4 per g of volatile suspended solid and per day was achieved at 0.2 atm of CO (0.17 mmol/L, and then the rate decreased with the amount of CO supplied. The intermediary metabolites such as acetate, H2 and propionate started to accumulate at higher CO concentrations. Inhibition experiments with 2-bromoethanesulfonic acid (BES, fluoroacetate, and vancomycin showed that in a mixed culture CO was converted mainly to acetate by acetogenic bacteria, which was further transformed to methane by acetoclastic methanogens, while direct methanogenic CO conversion was negligible. Methanogenesis was totally blocked at high pCO in the bottles (≥ 1 atm. However it was possible to achieve higher methanogenic potential under a 100% CO atmosphere after acclimation of the sludge to CO. This adaptation to high CO concentrations led to a shift in the archaeal population, then dominated by hydrogen-utilizing methanogens, which were able to take over acetoclastic methanogens, while syntrophic acetate oxidizing (SAO bacteria oxidized acetate into CO2 and H2. The disaggregation

Biomethanation of Syngas Using Anaerobic Sludge: Shift in the Catabolic Routes with the CO Partial Pressure Increase.

Science.gov (United States)

Sancho Navarro, Silvia; Cimpoia, Ruxandra; Bruant, Guillaume; Guiot, Serge R

2016-01-01

Syngas generated by thermal gasification of biomass or coal can be steam reformed and purified into methane, which could be used locally for energy needs, or re-injected in the natural gas grid. As an alternative to chemical catalysis, the main components of the syngas (CO, CO2, and H2) can be used as substrates by a wide range of microorganisms, to be converted into gas biofuels, including methane. This study evaluates the carboxydotrophic (CO-consuming) methanogenic potential present in an anaerobic sludge from an upflow anaerobic sludge bed (UASB) reactor treating waste water, and elucidates the CO conversion routes to methane at 35 ± 3°C. Kinetic activity tests under CO at partial pressures (pCO) varying from 0.1 to 1.5 atm (0.09-1.31 mmol/L in the liquid phase) showed a significant carboxydotrophic activity potential for growing conditions on CO alone. A maximum methanogenic activity of 1 mmol CH4 per g of volatile suspended solid and per day was achieved at 0.2 atm of CO (0.17 mmol/L), and then the rate decreased with the amount of CO supplied. The intermediary metabolites such as acetate, H2, and propionate started to accumulate at higher CO concentrations. Inhibition experiments with 2-bromoethanesulfonic acid (BES), fluoroacetate, and vancomycin showed that in a mixed culture CO was converted mainly to acetate by acetogenic bacteria, which was further transformed to methane by acetoclastic methanogens, while direct methanogenic CO conversion was negligible. Methanogenesis was totally blocked at high pCO in the bottles (≥1 atm). However it was possible to achieve higher methanogenic potential under a 100% CO atmosphere after acclimation of the sludge to CO. This adaptation to high CO concentrations led to a shift in the archaeal population, then dominated by hydrogen-utilizing methanogens, which were able to take over acetoclastic methanogens, while syntrophic acetate oxidizing (SAO) bacteria oxidized acetate into CO2 and H2. The disaggregation of the

Divergent Responses of the Diazotrophic Microbiome to Elevated CO2 in Two Rice Cultivars

Directory of Open Access Journals (Sweden)

Yongjie Yu

2018-06-01

Full Text Available The species-specific responses of plant growth to elevated atmospheric CO2 concentration (eCO2 could lead to N limitation and potentially influence the sustainability of ecosystem. Questions remain unanswered with regards to the response of soil N2-fixing community to eCO2 when developing high-yielding agroecosystem to dampen the future rate of increase in CO2 levels and associated climate warming. This study demonstrates the divergent eCO2 influences on the paddy diazotrophic community between weak- and strong-responsive rice cultivars. In response to eCO2, the diazotrophic abundance increased more for the strong-responsive cultivar treatments than for the weak-responsive ones. Only the strong-responsive cultivars decreased the alpha diversity and separated the composition of diazotrophic communities in response to eCO2. The topological indices of the ecological networks further highlighted the different co-occurrence patterns of the diazotrophic microbiome in rice cultivars under eCO2. Strong-responsive cultivars destabilized the diazotrophic community by complicating and centralizing the co-occurrence network as well as by shifting the hub species from Bradyrhizobium to Dechloromonas in response to eCO2. On the contrary, the network pattern of the weak-responsive cultivars was simplified and decentralized in response to eCO2, with the hub species shifting from Halorhodospira under aCO2 to Sideroxydans under eCO2. Collectively, the above information indicates that the strong-responsive cultivars could potentially undermine the belowground ecosystem from the diazotrophs perspective in response to eCO2. This information highlights that more attention should be paid to the stability of the belowground ecosystem when developing agricultural strategies to adapt prospective climatic scenarios by growing high-yielding crop cultivars under eCO2.

Radiation dosimetry by optically stimulated phosphorescence of CaF2:Mn

International Nuclear Information System (INIS)

Bernhardt, R.

1974-01-01

In addition to the light emission which occurs in TL, trapped electrons in CaF 2 :Mn can also be released by stimulation with visible and UV light. The measurement of stimulated light emission is disturbed by illumination. But there is an optically-stimulated phosphorescence, which permits to separate measurement of stimulated light emission and illumination. A theory is given. During illumination a part of the released electrons are captured by flat traps, which are emptied at room temperature. A dose dependent signal can be measured at a defined time after the stimulating pulse of visible light. Dosimeters (CaF 2 :Mn teflon disks) were illuminated by the light of a tungsten lamp. The dose response curve was found to be linear from 1 to 10 5 rads. The response curve obtained for optical stimulation was similar to the TL-response curve. Fading of the optically-stimulated signal was higher than TL-fading. Repeated readings of a single sample are possible. The number of readings is dependent on illumination conditions. Accuracy of sample to sample was about 3.5% (standard deviation). There are two background signals. (1) Post-irradiation phosphorescence occurs. Flat traps are also filled after 60 Co gamma excitation. The measurement of the signal is possible after decay of post-irradiation phosphorescence. (2) There is an optically-excited phosphorescence, which also occurs if all trapped electrons are released. The lower limit of dose measurements is given by deviations of optically-excited emission and the dark-current of the photomultiplier tube. (author)

Dynamics of Soil CO2 Profiles of Pinus sylvestris var. sylvestriformis Seedlings Under CO2 Concentration Doubled%CO2倍增条件下长白赤松幼苗土壤CO2廓线的动态

Institute of Scientific and Technical Information of China (English)

韩士杰; 张军辉; 周玉梅; 邹春静

2002-01-01

The gas-well system permanently installed in the soil was adopted for studying the dynamic relationship between CO2 profiles and seedling root growth of Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu. The study was conducted in the Open Research Station of Changbai Mountain Forest Ecological System, The Chinese Academy of Sciences from 1999 to 2001. Four treatments were arranged in the rectangular open-top chambers (OTCs): ambient CO2+no-seedling, 700 μmol/mol CO2+no-seedling, ambient CO2 +seedlings, 700 μmol/mol CO2+seedlings. By collecting and analyzing soil gas synchronously, it was found that the dynamics of CO2 profiles were related to the biological activity of seedlings. There were more roots distributed in the top soil and the boundary layer across soil and sand, which made more contributions to the CO2 profiles due to respiration root. Compared with the ambient CO2, elevated CO2 led to the peak of CO2 concentration distribution shifted from soil surface layer to the boundary layer as seasonally growing of seedling roots. It is suggested the gas-well system is an inexpensive, non-destructive and relatively sensitive method for study of soil CO2 concentration profiles.%采用固定在土壤中的气井系统,监测土壤剖面的CO2动态及其与长白赤松 (Pinus sylvestris var. sylvestriformis (Takenouchi) Cheng et C. D. Chu) 幼苗根系发展之间的关系.实验研究共设4种CO2处理,分别是环境CO2浓度,无苗;CO2为700 μmol/mol,无苗;环境CO2浓度,有苗;CO2为700 μmol/mol,有苗.通过对土壤剖面CO2气体的同步采集与分析表明:土壤CO2廓线与幼苗根系的生物活性密切相关.在土壤表面及壤土和沙土的边界层中,根系分布密集,根系的呼吸作用对那两个土层CO2贡献大;随着幼苗的季节生长,与环境CO2浓度比较,CO2倍增将导致土壤剖面上CO2�

Observation of vector and tensor light shifts in 87Rb using near-resonant, stimulated Raman spectroscopy

Science.gov (United States)

Hu, Qing-Qing; Freier, Christian; Sun, Yuan; Leykauf, Bastian; Schkolnik, Vladimir; Yang, Jun; Krutzik, Markus; Peters, Achim

2018-01-01

We present the derivation of the frequency-dependent scalar, vector, and tensor dynamical polarizabilities for the two hyperfine levels of the 87Rb atom 5 s ground state. Based on the characterization of the dynamical polarizabilities, we analyze and measure the differential vector and tensor light shift between the 5 s ground-state sublevels with near-resonant, stimulated Raman transitions. These results clarify that the tensor polarizabilities for the ground states of alkali atoms are absent when the light field is far detuned from the atomic resonance and the total electronic angular momentum J is a good quantum number. In the near-resonant case, the light shifts are nontrivial and the determination of the frequency-dependent vector and tensor dynamic polarizabilities will help to achieve higher fidelities for applications of neutral atoms in quantum information and precision measurements.

High temperature H2/CO2 separation using cobalt oxide silica membranes

Energy Technology Data Exchange (ETDEWEB)

Smart, S.; Diniz da Costa, J.C. [The University of Queensland, FIMLab - Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, Qld 4072 (Australia); Vente, J.F. [Energy research Centre of the Netherlands ECN, P.O. Box 1, 1755 ZG Petten (Netherlands)

2012-09-15

In this work high quality cobalt oxide silica membranes were synthesized on alumina supports using a sol-gel, dip coating method. The membranes were subsequently connected into a steel module using a graphite based proprietary sealing method. The sealed membranes were tested for single gas permeance of He, H2, N2 and CO2 at temperatures up to 600C and feed pressures up to 600 kPa. Pressure tests confirmed that the sealing system was effective as no gas leaks were observed during testing. A H2 permeance of 1.9 x 10{sup -7} mol m{sup -2} s{sup -1} Pa-1 was measured in conjunction with a H2/CO2 permselectivity of more than 1500, suggesting that the membranes had a very narrow pore size distribution and an average pore diameter of approximately 3 Angstrom. The high temperature testing demonstrated that the incorporation of cobalt oxide into the silica matrix produced a structure with a higher thermal stability, able to resist thermally induced densification up to at least 600C. Furthermore, the membranes were tested for H2/CO2 binary feed mixtures between 400 and 600C. At these conditions, the reverse of the water gas shift reaction occurred, inadvertently generating CO and water which increased as a function of CO2 feed concentration. The purity of H2 in the permeate stream significantly decreased for CO2 feed concentrations in excess of 50 vol%. However, the gas mixtures (H2, CO2, CO and water) had a more profound effect on the H2 permeate flow rates which significantly decreased, almost exponentially as the CO2 feed concentration increased.

Phloem function: A key to understanding and manipulating plant responses to rising atmospheric [CO2]?

Science.gov (United States)

Increasing atmospheric carbon dioxide concentration ([CO2]) directly stimulates photosynthesis and reduces stomatal conductance in C3 plants. Both of these physiological effects have the potential to alter phloem function at elevated [CO2]. Recent research has clearly established that photosynthetic...

The role of CD27-CD70-mediated T cell co-stimulation in vasculogenesis, arteriogenesis and angiogenesis.

Science.gov (United States)

Simons, K H; Aref, Z; Peters, H A B; Welten, S P; Nossent, A Y; Jukema, J W; Hamming, J F; Arens, R; de Vries, M R; Quax, P H A

2018-06-01

T cells have a distinctive role in neovascularization, which consists of arteriogenesis and angiogenesis under pathological conditions and vasculogenesis under physiological conditions. However, the role of co-stimulation in T cell activation in neovascularization has yet to be established. The aim of this study was to investigate the role T cell co-stimulation and inhibition in angiogenesis, arteriogenesis and vasculogenesis. Hind limb ischemia was induced by double ligation of the left femoral artery in mice and blood flow recovery was measured with Laser Doppler Perfusion Imaging in control, CD70 -/- , CD80/86 -/- , CD70/80/86 -/- and CTLA4 +/- mice. Blood flow recovery was significantly impaired in mice lacking CD70 compared to control mice, but was similar in CD80/86 -/- , CTLA4 +/- and control mice. Mice lacking CD70 showed impaired vasculogenesis, since the number of pre-existing collaterals was reduced as observed in the pia mater compared to control mice. In vitro an impaired capability of vascular smooth muscle cells (VSMC) to activate T cells was observed in VSMC lacking CD70. Furthermore, CD70 -/- , CD80/86 -/- and CD70/80/86 -/- mice showed reduced angiogenesis in the soleus muscle 10 days after ligation. Arteriogenesis was also decreased in CD70 -/- compared to control mice 10 and 28 days after surgery. The present study is the first to describe an important role for T cell activation via co-stimulation in angiogenesis, arteriogenesis and vasculogenesis, where the CD27-CD70 T cell co-stimulation pathway appears to be the most important co-stimulation pathway in pre-existing collateral formation and post-ischemic blood flow recovery, by arteriogenesis and angiogenesis. Copyright © 2018 Elsevier B.V. All rights reserved.

Cu-Sn Bimetallic Catalyst for Selective Aqueous Electroreduction of CO2 to CO

KAUST Repository

Sarfraz, Saad

2016-03-23

We report a selective and stable electrocatalyst utilizing non-noble metals consisting of Cu and Sn for the efficient and selective reduction of CO2 to CO over a wide potential range. The bimetallic electrode was prepared through the electrodeposition of Sn species on the surface of oxide-derived copper (OD-Cu). The Cu surface, when decorated with an optimal amount of Sn, resulted in a Faradaic efficiency (FE) for CO greater than 90% and a current density of −1.0 mA cm−2 at −0.6 V vs. RHE, compared to the CO FE of 63% and −2.1 mA cm−2 for OD-Cu. Excess Sn on the surface caused H2 evolution with a decreased current density. X-ray diffraction (XRD) suggests the formation of Cu-Sn alloy. Auger electron spectroscopy of the sample surface exhibits zero-valent Cu and Sn after the electrodeposition step. Density functional theory (DFT) calculations show that replacing a single Cu atom with a Sn atom leaves the d-band orbitals mostly unperturbed, signifying no dramatic shifts in the bulk electronic structure. However, the Sn atom discomposes the multi-fold sites on pure Cu, disfavoring the adsorption of H and leaving the adsorption of CO relatively unperturbed. Our catalytic results along with DFT calculations indicate that the presence of Sn on reduced OD-Cu diminishes the hydrogenation capability—i.e., the selectivity towards H2 and HCOOH—while hardly affecting the CO productivity. While the pristine monometallic surfaces (both Cu and Sn) fail to selectively reduce CO2, the Cu-Sn bimetallic electrocatalyst generates a surface that inhibits adsorbed H*, resulting in improved CO FE. This study presents a strategy to provide a low-cost non-noble metals that can be utilized as a highly selective electrocatalyst for the efficient aqueous reduction of CO2.

Faster turnover of new soil carbon inputs under increased atmospheric CO2.

Science.gov (United States)

van Groenigen, Kees Jan; Osenberg, Craig W; Terrer, César; Carrillo, Yolima; Dijkstra, Feike A; Heath, James; Nie, Ming; Pendall, Elise; Phillips, Richard P; Hungate, Bruce A

2017-10-01

Rising levels of atmospheric CO 2 frequently stimulate plant inputs to soil, but the consequences of these changes for soil carbon (C) dynamics are poorly understood. Plant-derived inputs can accumulate in the soil and become part of the soil C pool ("new soil C"), or accelerate losses of pre-existing ("old") soil C. The dynamics of the new and old pools will likely differ and alter the long-term fate of soil C, but these separate pools, which can be distinguished through isotopic labeling, have not been considered in past syntheses. Using meta-analysis, we found that while elevated CO 2 (ranging from 550 to 800 parts per million by volume) stimulates the accumulation of new soil C in the short term (soil C pool over either temporal scale. Our results are inconsistent with predictions of conventional soil C models and suggest that elevated CO 2 might increase turnover rates of new soil C. Because increased turnover rates of new soil C limit the potential for additional soil C sequestration, the capacity of land ecosystems to slow the rise in atmospheric CO 2 concentrations may be smaller than previously assumed. © 2017 John Wiley & Sons Ltd.

The other ocean acidification problem: CO2 as a resource among competitors for ecosystem dominance

Science.gov (United States)

Connell, Sean D.; Kroeker, Kristy J.; Fabricius, Katharina E.; Kline, David I.; Russell, Bayden D.

2013-01-01

Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO2) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO2 on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO2] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO2 experiments and data from ‘natural’ volcanic CO2 vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO2 conditions both in temperate and tropical conditions. The benefits of CO2 are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO2 world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO2 as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects. PMID:23980244

The other ocean acidification problem: CO2 as a resource among competitors for ecosystem dominance.

Science.gov (United States)

Connell, Sean D; Kroeker, Kristy J; Fabricius, Katharina E; Kline, David I; Russell, Bayden D

2013-01-01

Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO2) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO2 on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO2] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO2 experiments and data from 'natural' volcanic CO2 vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO2 conditions both in temperate and tropical conditions. The benefits of CO2 are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO2 world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO2 as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects.

Industrial CO2 emissions from energy use in Korea: A structural decomposition analysis

International Nuclear Information System (INIS)

Lim, Hea-Jin; Yoo, Seung-Hoon; Kwak, Seung-Jun

2009-01-01

This paper attempts to quantify energy consumption and CO 2 emissions in the industrial sectors of Korea. The sources of the changes in CO 2 emissions for the years 1990-2003 are investigated, in terms of a total of eight factors, through input-output structural decomposition analysis: changes in emission coefficient (caused by shifts in energy intensity and carbon intensity); changes in economic growth; and structural changes (in terms of shifts in domestic final demand, exports, imports of final and intermediate goods, and production technology). The results show that the rate of growth of industrial CO 2 emissions has drastically decreased since the 1998 financial crisis in Korea. The effect on emission reductions due to changes in energy intensity and domestic final demand surged in the second period (1995-2000), while the impact of exports steeply rose in the third period (2000-2003). Of all the individual factors, economic growth accounted for the largest increase in CO 2 emissions. The results of this analysis can be used to infer the potential for emission-reduction in Korea

Responses of soil microbial activity to cadmium pollution and elevated CO2.

Science.gov (United States)

Chen, Yi Ping; Liu, Qiang; Liu, Yong Jun; Jia, Feng An; He, Xin Hua

2014-03-06

To address the combined effects of cadmium (Cd) and elevated CO2 on soil microbial communities, DGGE (denaturing gradient gel electrophoresis) profiles, respiration, carbon (C) and nitrogen (N) concentrations, loessial soils were exposed to four levels of Cd, i.e., 0 (Cd0), 1.5 (Cd1.5), 3.0 (Cd3.0) and 6.0 (Cd6.0) mg Cd kg(-1) soil, and two levels of CO2, i.e., 360 (aCO2) and 480 (eCO2) ppm. Compared to Cd0, Cd1.5 increased fungal abundance but decreased bacterial abundance under both CO2 levels, whilst Cd3.0 and Cd6.0 decreased both fungal and bacterial abundance. Profiles of DGGE revealed alteration of soil microbial communities under eCO2. Soil respiration decreased with Cd concentrations and was greater under eCO2 than under aCO2. Soil total C and N were greater under higher Cd. These results suggest eCO2 could stimulate, while Cd pollution could restrain microbial reproduction and C decomposition with the restraint effect alleviated by eCO2.

Controlling Cooperative CO2 Adsorption in Diamine-Appended Mg2(dobpdc) Metal-Organic Frameworks.

Science.gov (United States)

Siegelman, Rebecca L; McDonald, Thomas M; Gonzalez, Miguel I; Martell, Jeffrey D; Milner, Phillip J; Mason, Jarad A; Berger, Adam H; Bhown, Abhoyjit S; Long, Jeffrey R

2017-08-02

In the transition to a clean-energy future, CO 2 separations will play a critical role in mitigating current greenhouse gas emissions and facilitating conversion to cleaner-burning and renewable fuels. New materials with high selectivities for CO 2 adsorption, large CO 2 removal capacities, and low regeneration energies are needed to achieve these separations efficiently at scale. Here, we present a detailed investigation of nine diamine-appended variants of the metal-organic framework Mg 2 (dobpdc) (dobpdc 4- = 4,4'-dioxidobiphenyl-3,3'-dicarboxylate) that feature step-shaped CO 2 adsorption isotherms resulting from cooperative and reversible insertion of CO 2 into metal-amine bonds to form ammonium carbamate chains. Small modifications to the diamine structure are found to shift the threshold pressure for cooperative CO 2 adsorption by over 4 orders of magnitude at a given temperature, and the observed trends are rationalized on the basis of crystal structures of the isostructural zinc frameworks obtained from in situ single-crystal X-ray diffraction experiments. The structure-activity relationships derived from these results can be leveraged to tailor adsorbents to the conditions of a given CO 2 separation process. The unparalleled versatility of these materials, coupled with their high CO 2 capacities and low projected energy costs, highlights their potential as next-generation adsorbents for a wide array of CO 2 separations.

Thermally and optically stimulated radiative processes in Eu and Y co-doped LiCaAlF{sub 6} crystal

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Kentaro, E-mail: ken-fukuda@tokuyama.co.jp [Tokuyama Corporation, 1-1 Mikage-cho, Shunan-shi, Yamaguchi 745-8648 (Japan); Yanagida, Takayuki; Fujimoto, Yutaka [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka 808-0196 (Japan)

2015-06-01

Yttrium co-doping was attempted to enhance dosimeter performance of Eu doped LiCaAlF{sub 6} crystal. Eu doped and Eu, Y co-doped LiCaAlF{sub 6} were prepared by the micro-pulling-down technique, and their dosimeter characteristics such as optically stimulated luminescence (OSL) and thermally stimulated luminescence (TSL) were investigated. By yttrium co-doping, emission intensities of OSL and TSL were enhanced by some orders of magnitude. In contrast, scintillation characteristics of yttrium co-doped crystal such as intensity of prompt luminescence induced by X-ray and light yield under neutron irradiation were degraded.

Toxic emissions and devalued CO2-neutrality

DEFF Research Database (Denmark)

Czeskleba-Dupont, Rolf

With reference to the paradigme shift regarding the formation of dioxins in municiplan solid waste incinerators experimental results are taken into account which lead to the suspicion that the same mechanism of de-novo-synthesis also applies to fireplace chimneys. This can explain the dioxin...... friendly effects of substituting wood burning for fossil fuels. With reference to Bent Sørensen's classical work on 'Renewable Energy' the assumption of CO2-neutrality regarding incineration is problematised when applied to plants with long rotation periods as trees. Registered CO2-emissions from wood...... burning are characterised together with particle and PAH emissions. The positive treatment of wood stove-technology in the Danish strategy for sustainable development (draft 2007) is critically evaluated and approaches to better regulation are identified....

Managing CO2 emissions in Nigeria

International Nuclear Information System (INIS)

Obioh, I.B.; Oluwole, A.F.; Akeredolu, F.A.

1994-01-01

The energy resources in Nigeria are nearly equally divided between fossil fuels and biofuels. The increasing pressure on them, following expected increased population growth, may lead to substantial emissions of carbon into the atmosphere. Additionally agricultural and forestry management practices in vogue are those related to savannah burning and rotational bush fallow systems, which have been clearly implicated as important sources of CO 2 and trace gases. An integrated model for the prediction of future CO 2 emissions based on fossil fuels and biomass fuels requirements, rates of deforestation and other land-use indices is presented. This is further based on trends in population and economic growth up to the year 2025, with a base year in 1988. A coupled carbon cycle-climate model based on the contribution of CO 2 and other trace gases is established from the proportions of integrated global warming effects for a 20-year averaging time using the product of global warming potential (GWP) and total emissions. An energy-technology inventory approach to optimal resources management is used as a tool for establishing the future scope of reducing the CO 2 emissions through improved fossil fuel energy efficiencies. Scenarios for reduction based on gradual to swift shifts from biomass to fossil and renewable fuels are presented together with expected policy options required to effect them

A high precision mass spectrometry method for measuring O2/N2 ratios and CO2 concentrations in air

International Nuclear Information System (INIS)

Marca, A.D.; Dennis, P.F.; Etchells, A.

2002-01-01

A full, detailed understanding of the global carbon budget is needed for robust modelling of global climate and environmental change. Since the industrial revolution the carbon cycle has been shifted from a steady state in which removal of CO 2 from the atmosphere through photosynthesis is balanced by its addition through respiration. Currently increased respiration due to deforestation, modern agricultural practises and the burning of fossil fuels dominates photosynthesis resulting in modern atmospheric CO 2 concentrations some 32% higher than the year 1800 levels. However, the CO 2 concentration rises are lower than expected from known fossil fuel combustion inventories. A significant proportion of the excess CO 2 is taken up by the oceans, however a missing carbon sink must still be invoked to account for the difference between measured and expected CO 2 rises. A global greening as a result of increased photosynthesis is required to close the circle

Hydrogen/deuterium fractionation factors of the aqueous ligand of cobalt in Co(H2O)62+ and Co(II)-substituted carbonic anhydrase

International Nuclear Information System (INIS)

Kassebaum, J.W.

1988-01-01

The author has measured the hydrogen/deuterium fractionation factor for the rapidly exchanging aqueous ligands of cobalt in Co(H 2 O) 6 2+ and in three Co(II)-substituted isozymes of carbonic anhydrase. The fractionation factor was determined from NMR relaxation rates at 300 MHz of the protons of water in mixed solutions of H 2 O and D 2 O containing these complexes. In each case, the paramagnetic contribution to 1/T 2 was greater than to 1/T 1 , consistent with a chemical shift mechanism affecting 1/T 2 . The fractionation factors obtained from T 2 were 0.73 ± 0.02 for Co(H 2 O) 6 2+ , 0.72 ± 0.02 for Co(II)-substituted carbonic anhydrase I, 0.77 ± 0.01 for Co(II)-substituted carbonic anhydrase II, and 1.00 ± 0.07 for Co(Il)-substituted carbonic anhydrase III. He concluded that fractionation factors in these cases determined from T 1 and T 2 measured isotope preferences for different populations of ligand sites. Since T 2 has a large contribution from a chemical shift mechanism, the fractionation factor determined from T 2 has a large contribution of the fractionation of inner shell ligands. The fractionation factor of Co(H 2 O) 6 2+ was used to interpret the solvent hydrogen isotope effects on the formation of complexes of cobalt with the bidentate ligands glycine, N,N-dimethylglycine, and acetylacetone. The contribution of the fractionation factor of the inner water shell in Co(H 2 O) 6 2+ did not account completely for the measured isotope effect, and that the hydrogen/deuterium fractionation of outer shell water makes a large contribution to the isotope effect on the formation of these complexes

CO{sub 2}-balance in the athmosphere and CO{sub 2}-utilisation : an engineering approach

Energy Technology Data Exchange (ETDEWEB)

Turunen, H.

2012-07-01

The subject of the thesis was to analyze by an engineering approach the global CO{sub 2} balance and CO{sub 2} utilisation. The aim was to apply methods and knowledge used in engineering sciences to describe the global CO{sub 2} balance and the role of CO{sub 2} in anthropogenic utilisation applications. Moreover barriers restricting commercialisation of new applications are discussed. These subjects were studied by literature reviews and calculations based on thermodynamics models. Engineering methods have shown to be applicable to describe the global balance of CO{sub 2} and to define by a numerical way the Earth's system carrying capacity. Direct and indirect actions, which mitigate the overload situation, were derived from the results. To screen out the attractive CO{sub 2} properties in utilisation applications a mapping analysis was carried out. Properties, which enhance mass and heat transfer, are one of the most meaningful characteristics from the chemical engineering point of view. Attractive properties are often achieved at the supercritical state. Engineering thermodynamic methods were used in fluid phase determination of the case studies. Even simple methods are sufficient to advice experimental research work. The thermodynamic knowledge is the basement in creation of industrial scale chemical processes. If detailed information on system properties is needed, a model development due to the special requirements of high pressure systems and CO{sub 2} features is required. This knowledge covers property information from all the components involved in chemical reactions. In addition to engineering knowledge successful technology transfer requires positive social structure as well. Finally, if the humankind is willing to mimic Nature and use light of the Sun as an energy source in engineering systems, development of thermodynamic methods is required also in this area. Especially the work terms, originally defined in classical mechanical thermodynamics

Tail gas treatment of sour-SEWGS CO2 product. Public version

Energy Technology Data Exchange (ETDEWEB)

Van Dijk, H.A.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

2012-06-15

This literature review covers the technologies suitable for the CO2-H2S separation within the context of CO2 purification of a pre-combustion captured stream intended for storage or reuse. The technologies considered cover existing industrially applied processes, emerging processes as well as processes in development. Several technologies capable of achieving the desired CO2-H2S separation were identified. Among them are liquid scrubbing processes Thiopaq and CrystaSulf producing elemental sulphur, selective oxidation to elemental sulphur such as MODOP or based on novel catalysts and sorbent-based (reactive) separations using low-, medium- or high-temperature (reactive) sorbents. SEWGS stands for Sorption Enhanced Water Gas Shift process.

Shape-shifting colloids via stimulated dewetting

Science.gov (United States)

Youssef, Mena; Hueckel, Theodore; Yi, Gi-Ra; Sacanna, Stefano

2016-01-01

The ability to reconfigure elementary building blocks from one structure to another is key to many biological systems. Bringing the intrinsic adaptability of biological systems to traditional synthetic materials is currently one of the biggest scientific challenges in material engineering. Here we introduce a new design concept for the experimental realization of self-assembling systems with built-in shape-shifting elements. We demonstrate that dewetting forces between an oil phase and solid colloidal substrates can be exploited to engineer shape-shifting particles whose geometry can be changed on demand by a chemical or optical signal. We find this approach to be quite general and applicable to a broad spectrum of materials, including polymers, semiconductors and magnetic materials. This synthetic methodology can be further adopted as a new experimental platform for designing and rapidly prototyping functional colloids, such as reconfigurable micro swimmers, colloidal surfactants and switchable building blocks for self-assembly. PMID:27426418

WATER-GAS SHIFT KINETICS OVER IRON OXIDE CATALYSTS AT MEMBRANE REACTOR CONDITIONS; A

International Nuclear Information System (INIS)

Carl R.F. Lund

2001-01-01

This report covers the second year of a project investigating water-gas shift catalysts for use in membrane reactors. It has been established that a simple iron high temperature shift catalyst becomes ineffective in a membrane reactor because the reaction rate is severely inhibited by the build-up of the product CO(sub 2). During the past year, an improved microkinetic model for water-gas shift over iron oxide was developed. Its principal advantage over prior models is that it displays the correct asymptotic behavior at all temperatures and pressures as the composition approaches equilibrium. This model has been used to explore whether it might be possible to improve the performance of iron high temperature shift catalysts under conditions of high CO(sub 2) partial pressure. The model predicts that weakening the surface oxygen bond strength by less than 5% should lead to higher catalytic activity as well as resistance to rate inhibition at higher CO(sub 2) partial pressures. Two promoted iron high temperature shift catalysts were studied. Ceria and copper were each studied as promoters since there were indications in the literature that they might weaken the surface oxygen bond strength. Ceria was found to be ineffective as a promoter, but preliminary results with copper promoted FeCr high temperature shift catalyst show it to be much more resistant to rate inhibition by high levels of CO(sub 2). Finally, the performance of sulfided CoMo/Al(sub 2)O(sub 3) catalysts under conditions of high CO(sub 2) partial pressure was simulated using an available microkinetic model for water-gas shift over this catalyst. The model suggests that this catalyst might be quite effective in a medium temperature water-gas shift membrane reactor, provided that the membrane was resistant to the H(sub 2)S that is required in the feed

Vehicle emissions of greenhouse gases and related tracers from a tunnel study: : CO: CO2, N2O: CO2, CH4: CO2, O2: CO2 ratios, and the stable isotopes 13C and 18O in CO2 and CO

NARCIS (Netherlands)

Popa, Maria Elena; Vollmer, M. K.; Jordan, A.; Brand, W. A.; Pathirana, S. L.; Rothe, M.; Röckmann, T.

2014-01-01

Measurements of CO2, CO, N2O and CH4 mole fractions, O2/N2 ratios and the stable isotopes 13C and 18O in CO2 and CO have been performed in air samples from the Islisberg highway tunnel (Switzerland). The molar CO : CO2 ratios, with an average of (4.15 ± 0.34) ppb:ppm, are lower than reported in

Boron nitride nanotube-mediated stimulation of cell co-culture on micro-engineered hydrogels.

Directory of Open Access Journals (Sweden)

Leonardo Ricotti

Full Text Available In this paper, we describe the effects of the combination of topographical, mechanical, chemical and intracellular electrical stimuli on a co-culture of fibroblasts and skeletal muscle cells. The co-culture was anisotropically grown onto an engineered micro-grooved (10 µm-wide grooves polyacrylamide substrate, showing a precisely tuned Young's modulus (∼ 14 kPa and a small thickness (∼ 12 µm. We enhanced the co-culture properties through intracellular stimulation produced by piezoelectric nanostructures (i.e., boron nitride nanotubes activated by ultrasounds, thus exploiting the ability of boron nitride nanotubes to convert outer mechanical waves (such as ultrasounds in intracellular electrical stimuli, by exploiting the direct piezoelectric effect. We demonstrated that nanotubes were internalized by muscle cells and localized in both early and late endosomes, while they were not internalized by the underneath fibroblast layer. Muscle cell differentiation benefited from the synergic combination of topographical, mechanical, chemical and nanoparticle-based stimuli, showing good myotube development and alignment towards a preferential direction, as well as high expression of genes encoding key proteins for muscle contraction (i.e., actin and myosin. We also clarified the possible role of fibroblasts in this process, highlighting their response to the above mentioned physical stimuli in terms of gene expression and cytokine production. Finally, calcium imaging-based experiments demonstrated a higher functionality of the stimulated co-cultures.

Role of CO2 in the oxy-dehydrogenation of ethylbenzene to styrene on the CeO2(111) surface

Science.gov (United States)

Fan, Hong-Xia; Feng, Jie; Li, Wen-Ying; Li, Xiao-Hong; Wiltowski, Tomasz; Ge, Qing-Feng

2018-01-01

The role of CO2 in the ethylbenzene oxy-dehydrogenation to styrene on the CeO2(111) surface was thoroughly investigated by the density functional theory (DFT) calculations. Results show that the first Csbnd H bond of ethylbenzene is activated via the oxo-insertion with a barrier of 1.70 eV, resulting in a 2-phenylethyl species and an H atom adsorbed on two-adjacent-lattice oxygen. The H adatom forms a hydroxyl-like species (denoted as O*H). The subsequent dehydrogenation to styrene can be assisted by either the next lattice oxygen (pathway R1) or the O*H species (pathway R2). The two pathways have almost the same activation energy (0.84 eV for R1 and 0.85 eV for R2), forming a new O*H and desorbing a H2O molecule while leaving an oxygen vacancy on the surface, respectively. In the presence of CO2, it will react with O*H through the reverse water gas shift reaction with an activation barrier of 0.98 eV and reaction energy of 0.30 eV. The reverse water gas shift reaction helps to clear the H adatoms from the lattice oxygen, thereby competing with styrene formation via pathway R2. However, the activation energy following the reverse water gas shift mechanism is 0.13 eV higher than that of styrene formation via pathway R2. Therefore, the formation of oxygen vacancy cannot be inhibited, while CO2 can react with the surface oxygen vacancy to produce CO with a high activation energy of 2.10 eV.

Air-ice CO2 fluxes and pCO2 dynamics in the Arctic coastal area (Amundsen Gulf, Canada)

Science.gov (United States)

Geilfus, Nicolas-Xavier; Tison, Jean Louis; Carnat, Gauthier; Else, Brent; Borges, Alberto V.; Thomas, Helmuth; Shadwick, Elizabeth; Delille, Bruno

2010-05-01

Sea ice covers about 7% of the Earth surface at its maximum seasonal extent. For decades sea ice was assumed to be an impermeable and inert barrier for air - sea exchange of CO2 so that global climate models do not include CO2 exchange between the oceans and the atmosphere in the polar regions. However, uptake of atmospheric CO2 by sea ice cover was recently reported raising the need to further investigate pCO2 dynamics in the marine cryosphere realm and related air-ice CO2 fluxes. In addition, budget of CO2 fluxes are poorly constrained in high latitudes continental shelves [Borges et al., 2006]. We report measurements of air-ice CO2 fluxes above the Canadian continental shelf and compare them to previous measurements carried out in Antarctica. We carried out measurements of pCO2 within brines and bulk ice, and related air-ice CO2 fluxes (chamber method) in Antarctic first year pack ice ("Sea Ice Mass Balance in Antarctica -SIMBA" drifting station experiment September - October 2007) and in Arctic first year land fast ice ("Circumpolar Flaw Lead" - CFL, April - June 2008). These 2 experiments were carried out in contrasted sites. SIMBA was carried out on sea ice in early spring while CFL was carried out in from the middle of the winter to the late spring while sea ice was melting. Both in Arctic and Antarctic, no air-ice CO2 fluxes were detected when sea ice interface was below -10°C. Slightly above -10°C, fluxes toward the atmosphere were observed. In contrast, at -7°C fluxes from the atmosphere to the ice were significant. The pCO2 of the brine exhibits a same trend in both hemispheres with a strong decrease of the pCO2 anti-correlated with the increase of sea ice temperature. The pCO2 shifted from a large over-saturation at low temperature to a marked under-saturation at high temperature. These air-ice CO2 fluxes are partly controlled by the permeability of the air-ice interface, which depends of the temperature of this one. Moreover, air-ice CO2 fluxes are

Spectroscopic analysis of PMMA/PVC blends containing CoCl2

Directory of Open Access Journals (Sweden)

N.S. Alghunaim

2015-01-01

Full Text Available Composites of polymethyl methacrylate (PMMA and polyvinyl chloride (PVC polymer blend containing different concentrations (⩽10 wt. of cobalt chloride (CoCl2 were prepared by casting techniques. The changes of the structural, spectroscopic, optical and thermal parameters of the samples are studied using different tools. FT-IR spectroscopy confirmed the complexation between the blends and Co+2-ions. The decrease or increase of IR band intensity with some shifts of other bands suggests an interaction and compatibility between PMMA/PVC blends with CoCl2 take place. The Ultra violet and visible (UV/Vis spectra indicated that the presence of band gap energy depends on increasing of CoCl2 contents. The absorption intensity of the samples doped with CoCl2 becomes faint lower than the pure blend. The values of energy gap for direct and indirect transition decreases with the increase of CoCl2 due to the presence of charge transfer between PMMA/PVC and CoCl2. The thermogravimetric analysis (TGA curves for all the samples have the same behavior and more steps of decomposition were observed. The reduction of mass loss for samples containing CoCl2 compared to the pure blend was observed and it was attributed to crosslink formation between the blend and CoCl2.

Co-culture with human synovium-derived mesenchymal stem cells inhibits inflammatory activity and increases cell proliferation of sodium nitroprusside-stimulated chondrocytes

International Nuclear Information System (INIS)

Ryu, Jae-Sung; Jung, Yeon-Hwa; Cho, Mi-Young; Yeo, Jee Eun; Choi, Yun-Jin; Kim, Yong Il; Koh, Yong-Gon

2014-01-01

Highlights: • Co-culture of hSDMSCs with SNP-stimulated chondrocytes improves anti-inflammation. • Co-culture system produces IGF-1. • Co-culture system suppresses inflammatory genes expression. • Co-culture system improves cell proliferation. • Exogenous IGF-1 inhibits inflammatory activity in SNP-stimulated chondrocytes. - Abstract: Rheumatoid arthritis (RA) and osteoarthritis (OA) are primarily chronic inflammatory diseases. Mesenchymal stem cells (MSCs) have the ability to differentiate into cells of the mesodermal lineage, and to regulate immunomodulatory activity. Specifically, MSCs have been shown to secrete insulin-like growth factor 1 (IGF-1). The purpose of the present study was to examine the inhibitory effects on inflammatory activity from a co-culture of human synovium-derived mesenchymal stem cells (hSDMSCs) and sodium nitroprusside (SNP)-stimulated chondrocytes. First, chondrocytes were treated with SNP to generate an in vitro model of RA or OA. Next, the co-culture of hSDMSCs with SNP-stimulated chondrocytes reduced inflammatory cytokine secretion, inhibited expression of inflammation activity-related genes, generated IGF-1 secretion, and increased the chondrocyte proliferation rate. To evaluate the effect of IGF-1 on inhibition of inflammation, chondrocytes pre-treated with IGF-1 were treated with SNP, and then the production of inflammatory cytokines was analyzed. Treatment with IGF-1 was shown to significantly reduce inflammatory cytokine secretion in SNP-stimulated chondrocytes. Our results suggest that hSDMSCs offer a new strategy to promote cell-based cartilage regeneration in RA or OA

Co-culture with human synovium-derived mesenchymal stem cells inhibits inflammatory activity and increases cell proliferation of sodium nitroprusside-stimulated chondrocytes

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jae-Sung; Jung, Yeon-Hwa; Cho, Mi-Young; Yeo, Jee Eun; Choi, Yun-Jin; Kim, Yong Il; Koh, Yong-Gon, E-mail: yonseranglab@daum.net

2014-05-16

Highlights: • Co-culture of hSDMSCs with SNP-stimulated chondrocytes improves anti-inflammation. • Co-culture system produces IGF-1. • Co-culture system suppresses inflammatory genes expression. • Co-culture system improves cell proliferation. • Exogenous IGF-1 inhibits inflammatory activity in SNP-stimulated chondrocytes. - Abstract: Rheumatoid arthritis (RA) and osteoarthritis (OA) are primarily chronic inflammatory diseases. Mesenchymal stem cells (MSCs) have the ability to differentiate into cells of the mesodermal lineage, and to regulate immunomodulatory activity. Specifically, MSCs have been shown to secrete insulin-like growth factor 1 (IGF-1). The purpose of the present study was to examine the inhibitory effects on inflammatory activity from a co-culture of human synovium-derived mesenchymal stem cells (hSDMSCs) and sodium nitroprusside (SNP)-stimulated chondrocytes. First, chondrocytes were treated with SNP to generate an in vitro model of RA or OA. Next, the co-culture of hSDMSCs with SNP-stimulated chondrocytes reduced inflammatory cytokine secretion, inhibited expression of inflammation activity-related genes, generated IGF-1 secretion, and increased the chondrocyte proliferation rate. To evaluate the effect of IGF-1 on inhibition of inflammation, chondrocytes pre-treated with IGF-1 were treated with SNP, and then the production of inflammatory cytokines was analyzed. Treatment with IGF-1 was shown to significantly reduce inflammatory cytokine secretion in SNP-stimulated chondrocytes. Our results suggest that hSDMSCs offer a new strategy to promote cell-based cartilage regeneration in RA or OA.

The Cheshire-cat-like Behavior of 2nu(sub 3) Overtone of Co2 near 2.134 micron: NIR Lab Spectra of Solid CO2 in H2O and CH3OH

Science.gov (United States)

Bernstein, Max; Sandford, Scott; Cruikshank, Dale

2005-01-01

Infrared (IR) spectra have demonstrated that solid H2O is very common in the outer Solar System, and solid carbon dioxide (CO2) has been detected on icy satellites, comets, and planetismals throughout the outer Solar System. In such environments, CO2 and H2O must sometimes be mixed at a molecular level, changing their IR absorption features. In fact, the IR spectra of CO2-H2O mixtures are not equivalent to a linear combination of the spectra of the pure materials. Laboratory IR spectra of pure CO2 and H2O have been published but a lack of near-IR spectra of CO2-H2O mixtures has made the interpretation of outer Solar System spectra more difficult. We present near infrared (IR) spectra of CO2 in H2O and in CH3OH compared to that of pure solid CO2 and find significant differences. Peaks not present in either pure H2O or pure CO2 spectra become evident. First, the CO2 (2nu(sub 3)) overtone near 2.134 micron (4685/ cm) that is not seen in pure solid CO2 is prominent in the spectrum of a CO2/H2O = 25 mixture. Second, a 2.74 micron (3650/ cm) dangling OH feature of water (and a potentially related peak at 1.89 micron) appear in the spectra of CO2-H2O ice mixtures, but may not be specific to the presence of CO2. Other CO2 peaks display shifts in position and increased width because of intermolecular interactions with water. Changes in CO2 peak positions and profiles on warming of a CO2/H2O = 5 mixture are consistent with 'segregation' of the ice into nearly pure separate components. Absolute strengths for absorptions of CO2 in solid H2O are estimated. Similar results are observed for CO2 in solid CH3OH. Since the CO2 ( 2nu(sub 3)) overtone near 2.134 micron (4685/ cm) is not present in pure CO2 but prominent in mixtures it may be a good observational indicator of whether solid CO2 is a pure material or intimately mixed with other molecules. Significant changes in the near IR spectrum of solid CO2 in the presence of H2O and CH3OH means that the abundance of solid CO2 in the

Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation

DEFF Research Database (Denmark)

Frahm, Ken Steffen; Andersen, Ole K.; Arendt-Nielsen, Lars

2010-01-01

Background: CO(2) lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial...... to deeper skin layers. Methods: In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO(2) laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were...... compared to the subjective pain intensity ratings from 16 subjects and to the surface skin temperature distributions measured by an infrared camera. Results: The stimulations were sensed significantly slower and less intense in glabrous skin than they were in hairy skin (MANOVA, p

Structural, electrical and magnetic studies of Co:SnO{sub 2} and (Co,Mo):SnO{sub 2} films prepared by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Dalui, S., E-mail: ssdalui@fc.ul.pt [University of Lisbon, Physics Dept. and ICEMS, 1749-016 Lisboa (Portugal); Instituto Superior de Engenharia de Lisboa and ICEMS, 1959-007 Lisboa (Portugal); Rout, S. [University of Lisbon, Physics Dept. and ICEMS, 1749-016 Lisboa (Portugal); Silvestre, A.J. [Instituto Superior de Engenharia de Lisboa and ICEMS, 1959-007 Lisboa (Portugal); Lavareda, G. [New University of Lisbon, Mater. Sci. Dept. and CTS, 2829-516 Caparica (Portugal); Pereira, L.C.J. [Instituto Superior Técnico, ITN and CFMCUL, 2686-953 Sacavém (Portugal); Brogueira, P. [Instituto Superior Técnico, Physics Dept. and ICEMS, 1049-001 Lisboa (Portugal); Conde, O. [University of Lisbon, Physics Dept. and ICEMS, 1749-016 Lisboa (Portugal)

2013-08-01

Here we report on the structural, optical, electrical and magnetic properties of Co-doped and (Co,Mo)-codoped SnO{sub 2} thin films deposited on r-cut sapphire substrates by pulsed laser deposition. Substrate temperature during deposition was kept at 500 °C. X-ray diffraction analysis showed that the undoped and doped films are crystalline with predominant orientation along the [1 0 1] direction regardless of the doping concentration and doping element. Optical studies revealed that the presence of Mo reverts the blue shift trend observed for the Co-doped films. For the Co and Mo doping concentrations studied, the incorporation of Mo did not contribute to increase the conductivity of the films or to enhance the ferromagnetic order of the Co-doped films.

Marine Microphytobenthic Assemblage Shift along a Natural Shallow-Water CO2 Gradient Subjected to Multiple Environmental Stressors

OpenAIRE

Johnson, V; Brownlee, C; Milazzo, M; Hall-Spencer, J

2015-01-01

Predicting the effects of anthropogenic CO2 emissions on coastal ecosystems requires an understanding of the responses of algae, since these are a vital functional component of shallow-water habitats. We investigated microphytobenthic assemblages on rock and sandy habitats along a shallow subtidal pCO2 gradient near volcanic seeps in the Mediterranean Sea. Field studies of natural pCO2 gradients help us understand the likely effects of ocean acidification because entire communities are subjec...

CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants.

Science.gov (United States)

Bloom, Arnold J; Asensio, Jose Salvador Rubaio; Randall, Lesley; Rachmilevitch, Shimon; Cousins, Asaph B; Carlisle, Eli A

2012-02-01

The CO2 concentration in Earth's atmosphere may double during this century. Plant responses to such an increase depend strongly on their nitrogen status, but the reasons have been uncertain. Here, we assessed shoot nitrate assimilation into amino acids via the shift in shoot CO2 and O2 fluxes when plants received nitrate instead of ammonium as a nitrogen source (deltaAQ). Shoot nitrate assimilation became negligible with increasing CO2 in a taxonomically diverse group of eight C3 plant species, was relatively insensitive to CO2 in three C4 species, and showed an intermediate sensitivity in two C3-C4 intermediate species. We then examined the influence of CO2 level and ammonium vs. nitrate nutrition on growth, assessed in terms of changes in fresh mass, of several C3 species and a Crassulacean acid metabolism (CAM) species. Elevated CO2 (720 micromol CO2/mol of all gases present) stimulated growth or had no effect in the five C3 species tested when they received ammonium as a nitrogen source but inhibited growth or had no effect if they received nitrate. Under nitrate, two C3 species grew faster at sub-ambient (approximately 310 micromol/mol) than elevated CO2. A CAM species grew faster at ambient than elevated or sub-ambient CO2 under either ammonium or nitrate nutrition. This study establishes that CO2 enrichment inhibits shoot nitrate assimilation in a wide variety of C3 plants and that this phenomenon can have a profound effect on their growth. This indicates that shoot nitrate assimilation provides an important contribution to the nitrate assimilation of an entire C3 plant. Thus, rising CO2 and its effects on shoot nitrate assimilation may influence the distribution of C3 plant species.

Increasing coccolith calcification during CO2 rise of the penultimate deglaciation (Termination II)

DEFF Research Database (Denmark)

Meier, K. J. S.; Berger, C.; Kinkel, Hanno

2014-01-01

during Termination II. This is partly due to an assemblage shift towards larger and heavier calcifying morphotypes, but mainly an effect of increasing coccolithophore calcification. This increase is exactly mirroring the rise in atmospheric CO2, contradicting previous findings from Termination I......Glacial to interglacial environmental changes have a strong impact on coccolithophore assemblage composition. At the same time, glacial terminations are characterised by an increase in atmospheric CO2 concentration. In order to determine how these two processes influence the calcite production...... for the coccolithophore calcification increase during atmospheric CO2 rise. Our results illustrate that even during rising atmospheric CO2 the conditions of the seawater carbonate system can be favourable for coccolithophore calcification. The total CaCO3 production of a coccolithophore assemblage under increasing CO2...

Element Pool Changes within a Scrub-Oak Ecosystem after 11 Years of Exposure to Elevated CO2

Science.gov (United States)

Duval, Benjamin D.; Dijkstra, Paul; Drake, Bert G.; Johnson, Dale W.; Ketterer, Michael E.; Megonigal, J. Patrick; Hungate, Bruce A.

2013-01-01

The effects of elevated CO2 on ecosystem element stocks are equivocal, in part because cumulative effects of CO2 on element pools are difficult to detect. We conducted a complete above and belowground inventory of non-nitrogen macro- and micronutrient stocks in a subtropical woodland exposed to twice-ambient CO2 concentrations for 11 years. We analyzed a suite of nutrient elements and metals important for nutrient cycling in soils to a depth of ∼2 m, in leaves and stems of the dominant oaks, in fine and coarse roots, and in litter. In conjunction with large biomass stimulation, elevated CO2 increased oak stem stocks of Na, Mg, P, K, V, Zn and Mo, and the aboveground pool of K and S. Elevated CO2 increased root pools of most elements, except Zn. CO2-stimulation of plant Ca was larger than the decline in the extractable Ca pool in soils, whereas for other elements, increased plant uptake matched the decline in the extractable pool in soil. We conclude that elevated CO2 caused a net transfer of a subset of nutrients from soil to plants, suggesting that ecosystems with a positive plant growth response under high CO2 will likely cause mobilization of elements from soil pools to plant biomass. PMID:23717607

Numerical simulation of Class 3 hydrate reservoirs exploiting using horizontal well by depressurization and thermal co-stimulation

International Nuclear Information System (INIS)

Yang, Shengwen; Lang, Xuemei; Wang, Yanhong; Wen, Yonggang; Fan, Shuanshi

2014-01-01

Highlights: • Depressurization and thermal co-stimulation using horizontal well were proposed. • 3D stimulation showed that gas release rate was 3 × 10 5 m 3 per day within 450 days. • 2D stimulation showed that Class 3 hydrates could be dissociated within 8500 days. • 2D Simulation showed that heat flow was 1620 W lasting 1500 days, and decreased fast. • 1.1× 10 5 kg water was collected within 2000 days and then no more water was produced. - Abstract: Class 3 hydrate reservoirs exploiting using horizontal well by depressurization and thermal co-stimulation was simulated using the HydarteResSim code. Results showed that more than 20% of hydrates in the reservoirs had been dissociated within 450 days at the well temperature of 42 °C and well pressure of 0.1P 0 , 0.2P 0 (P 0 is the initial pressure of the reservoirs, simplifying 42 °C and 0.1P 0 , 42 °C and 0.2P 0 ). While the production behavior of 42 °C and 0.5P 0 , 42 °C and 0.8P 0 were not so exciting. In order to understand the production character of the well in long term, the cross section of 1 m length reservoirs was simulated. Simulation results showed that 4.5 × 10 5 m 3 gas would be collected within 4500 days and 1.1 × 10 6 kg water could be produced within 1500 days in the well at 42 °C and 0.1P 0 . 3.5 × 10 5 m 3 gas would be collected within 8500 days and 1.1 × 10 6 kg water could be produced within 1500 days in the well at 42 °C and 0.2P 0 . The heat flow was 1620 W at the beginning and then decreased rapidly in the two cases. For reservoirs of 1495.2 m in length, about 6.7 × 10 8 m 3 and 5.3 × 10 8 m 3 gas would be collected in the well corresponding to conditions of 42 °C and 0.1P 0 , and 42 °C and 0.2P 0

Potential predictors for the amount of intra-operative brain shift during deep brain stimulation surgery

Science.gov (United States)

Datteri, Ryan; Pallavaram, Srivatsan; Konrad, Peter E.; Neimat, Joseph S.; D'Haese, Pierre-François; Dawant, Benoit M.

2011-03-01

A number of groups have reported on the occurrence of intra-operative brain shift during deep brain stimulation (DBS) surgery. This has a number of implications for the procedure including an increased chance of intra-cranial bleeding and complications due to the need for more exploratory electrodes to account for the brain shift. It has been reported that the amount of pneumocephalus or air invasion into the cranial cavity due to the opening of the dura correlates with intraoperative brain shift. Therefore, pre-operatively predicting the amount of pneumocephalus expected during surgery is of interest toward accounting for brain shift. In this study, we used 64 DBS patients who received bilateral electrode implantations and had a post-operative CT scan acquired immediately after surgery (CT-PI). For each patient, the volumes of the pneumocephalus, left ventricle, right ventricle, third ventricle, white matter, grey matter, and cerebral spinal fluid were calculated. The pneumocephalus was calculated from the CT-PI utilizing a region growing technique that was initialized with an atlas-based image registration method. A multi-atlas-based image segmentation method was used to segment out the ventricles of each patient. The Statistical Parametric Mapping (SPM) software package was utilized to calculate the volumes of the cerebral spinal fluid (CSF), white matter and grey matter. The volume of individual structures had a moderate correlation with pneumocephalus. Utilizing a multi-linear regression between the volume of the pneumocephalus and the statistically relevant individual structures a Pearson's coefficient of r = 0.4123 (p = 0.0103) was found. This study shows preliminary results that could be used to develop a method to predict the amount of pneumocephalus ahead of the surgery.

Mathematical Analysis of High-Temperature Co-electrolysis of CO2 and O2 Production in a Closed-Loop Atmosphere Revitalization System

Energy Technology Data Exchange (ETDEWEB)

Michael G. McKellar; Manohar S. Sohal; Lila Mulloth; Bernadette Luna; Morgan B. Abney

2010-03-01

NASA has been evaluating two closed-loop atmosphere revitalization architectures based on Sabatier and Bosch carbon dioxide, CO2, reduction technologies. The CO2 and steam, H2O, co-electrolysis process is another option that NASA has investigated. Utilizing recent advances in the fuel cell technology sector, the Idaho National Laboratory, INL, has developed a CO2 and H2O co-electrolysis process to produce oxygen and syngas (carbon monoxide, CO and hydrogen, H2 mixture) for terrestrial (energy production) application. The technology is a combined process that involves steam electrolysis, CO2 electrolysis, and the reverse water gas shift (RWGS) reaction. A number of process models have been developed and analyzed to determine the theoretical power required to recover oxygen, O2, in each case. These models include the current Sabatier and Bosch technologies and combinations of those processes with high-temperature co-electrolysis. The cases of constant CO2 supply and constant O2 production were evaluated. In addition, a process model of the hydrogenation process with co-electrolysis was developed and compared. Sabatier processes require the least amount of energy input per kg of oxygen produced. If co-electrolysis replaces solid polymer electrolyte (SPE) electrolysis within the Sabatier architecture, the power requirement is reduced by over 10%, but only if heat recuperation is used. Sabatier processes, however, require external water to achieve the lower power results. Under conditions of constant incoming carbon dioxide flow, the Sabatier architectures require more power than the other architectures. The Bosch, Boudouard with co-electrolysis, and the hydrogenation with co-electrolysis processes require little or no external water. The Bosch and hydrogenation processes produce water within their reactors, which aids in reducing the power requirement for electrolysis. The Boudouard with co-electrolysis process has a higher electrolysis power requirement because carbon

Detailed H2 and CO Electrochemistry for a MEA Model Fueled by Syngas

KAUST Repository

Lee, W. Y.

2015-07-17

© The Electrochemical Society. SOFCs can directly oxidize CO in addition to H2, which allows them to be coupled to a gasifier. Many membrane-electrode-assembly (MEA) models neglect CO electrochemistry due to sluggish kinetics and the water-gas-shift reaction, but CO oxidation may be important for high CO-content syngas. The 1D-MEA model presented here incorporates detailed mechanisms for both H2 and CO oxidation, individually fitted to experimental data. These mechanisms are then combined into a single model, which provides a good fit to experimental data for H2/CO mixtures. Furthermore, the model fits H2/CO data best when a single chargetransfer step in the H2 mechanism is assumed to be rate-limiting for all current densities. This differs from the result for H2/H2O mixtures, where H2 adsorption becomes rate-limiting at high current densities. These results indicate that CO oxidation cannot be neglected in MEA models running on CO-rich syngas, and that CO oxidation can alter the H2 oxidation mechanism.

The growth response of Alternanthera philoxeroides in a simulated post-combustion emission with ultrahigh [CO2] and acidic pollutants

International Nuclear Information System (INIS)

Xu Chengyuan; Griffin, Kevin L.; Blazier, John C.; Craig, Elizabeth C.; Gilbert, Dominique S.; Sritrairat, Sanpisa; Anderson, O. Roger; Castaldi, Marco J.; Beaumont, Larry

2009-01-01

Although post-combustion emissions from power plants are a major source of air pollution, they contain excess CO 2 that could be used to fertilize commercial greenhouses and stimulate plant growth. We addressed the combined effects of ultrahigh [CO 2 ] and acidic pollutants in flue gas on the growth of Alternanthera philoxeroides. When acidic pollutants were excluded, the biomass yield of A. philoxeroides saturated near 2000 μmol mol -1 [CO 2 ] with doubled biomass accumulation relative to the ambient control. The growth enhancement was maintained at 5000 μmol mol -1 [CO 2 ], but declined when [CO 2 ] rose above 1%, in association with a strong photosynthetic inhibition. Although acidic components (SO 2 and NO 2 ) significantly offset the CO 2 enhancement, the aboveground yield increased considerably when the concentration of pollutants was moderate (200 times dilution). Our results indicate that using excess CO 2 from the power plant emissions to optimize growth in commercial green house could be viable. - Diluted post-combustion emission gas from fossil fuel fired power plants stimulate the growth of C 3 plant.

CO2 reduction potential of future coal gasification based power generation technologies

International Nuclear Information System (INIS)

Jansen, D.; Oudhuis, A.B.J.; Van Veen, H.M.

1992-03-01

Assessment studies are carried out on coal gasification power plants integrated with gas turbines (IGCC) or molten carbonate fuel cells (MCFC) without and with CO 2 -removal. System elements include coal gasification, high-temperature gas-cleaning, molten carbonate fuel cells or gas turbines, CO shift, membrane separation, CO 2 recovery and a bottoming cycle. Various system configurations are evaluated on the basis of thermodynamic computations. The energy balances of the various system configurations clearly indicate that integrated coal gasification MCFC power plants (IGMCFC) with CO 2 removal have high efficiencies (42-47% LHV) compared to IGCC power plants with CO 2 -removal (33-38% LHV) and that the CO 2 -removal is simplified due to the specific properties of the molten carbonate fuel cells. IGMCFC is therefore an option with future prospective in the light of clean coal technologies for power generation with high energy efficiencies and low emissions. 2 figs., 3 tabs., 10 refs

Investigation of attractive and repulsive interactions associated with ketones in supercritical CO2, based on Raman spectroscopy and theoretical calculations.

Science.gov (United States)

Kajiya, Daisuke; Saitow, Ken-ichi

2013-08-07

Carbonyl compounds are solutes that are highly soluble in supercritical CO2 (scCO2). Their solubility governs the efficiency of chemical reactions, and is significantly increased by changing a chromophore. To effectively use scCO2 as solvent, it is crucial to understand the high solubility of carbonyl compounds, the solvation structure, and the solute-solvent intermolecular interactions. We report Raman spectroscopic data, for three prototypical ketones dissolved in scCO2, and four theoretical analyses. The vibrational Raman spectra of the C=O stretching modes of ketones (acetone, acetophenone, and benzophenone) were measured in scCO2 along the reduced temperature Tr = T∕Tc = 1.02 isotherm as a function of the reduced density ρr = ρ∕ρc in the range 0.05-1.5. The peak frequencies of the C=O stretching modes shifted toward lower energies as the fluid density increased. The density dependence was analyzed by using perturbed hard-sphere theory, and the shift was decomposed into attractive and repulsive energy components. The attractive energy between the ketones and CO2 was up to nine times higher than the repulsive energy, and its magnitude increased in the following order: acetone attractive energy and optimized the relative configuration between each solute and CO2. According to theoretical calculations for the dispersion energy, the dipole-induced-dipole interaction energy, and the frequency shift due to their interactions, the experimentally determined attractive energy differences in the three solutes were attributed to the dispersion energies that depended on a chromophore attached to the carbonyl groups. It was found that the major intermolecular interaction with the attractive shift varied from dipole-induced dipole to dispersion depending on the chromophore in the ketones in scCO2. As the common conclusion for the Raman spectral measurements and the four theoretical calculations, solute polarizability, modified by the chromophore, was at the core of

Methane production from formate, acetate and H2/CO2; focusing on kinetics and microbial characterization

DEFF Research Database (Denmark)

Pan, Xiaofang; Angelidaki, Irini; Alvarado-Morales, Merlin

2016-01-01

For evaluating the methanogenesis from typical methanogenic precursors (formate, acetate and H-2/CO2), CH4 production kinetics were investigated at 37 +/- 1 degrees C in batch anaerobic digestion tests and stimulated by modified Gompertz model. The results showed that maximum methanation rate from...... formate, acetate and H-2/CO2 were 19.58 +/- 0.49, 42.65 +/- 1.17 and 314.64 +/- 3.58 N mL/gVS/d in digested manure system and 6.53 +/- 0.31, 132.04 +/- 3.96 and 640.16 +/- 19.92 N mL/gVS/d in sewage sludge system during second generation incubation. Meanwhile the model could not fit well in granular...... sludge system, while the rate of formate methanation was faster than from H-2/CO2 and acetate. Considering both the kinetic results and microbial assay we could conclude that H-2/CO2 methanation was the fastest methanogenic step in digested manure and sewage sludge system with Methanomicrobiales...

Hydronium-Induced Switching between CO2 Electroreduction Pathways.

Science.gov (United States)

Seifitokaldani, Ali; Gabardo, Christine M; Burdyny, Thomas; Dinh, Cao-Thang; Edwards, Jonathan P; Kibria, Md Golam; Bushuyev, Oleksandr S; Kelley, Shana O; Sinton, David; Sargent, Edward H

2018-03-21

Over a broad range of operating conditions, many CO 2 electroreduction catalysts can maintain selectivity toward certain reduction products, leading to materials and surfaces being categorized according to their products; here we ask, is product selectivity truly a property of the catalyst? Silver is among the best electrocatalysts for CO in aqueous electrolytes, where it reaches near-unity selectivity. We consider the hydrogenations of the oxygen and carbon atoms via the two proton-coupled-electron-transfer processes as chief determinants of product selectivity; and find using density functional theory (DFT) that the hydronium (H 3 O + ) intermediate plays a key role in the first oxygen hydrogenation step and lowers the activation energy barrier for CO formation. When this hydronium influence is removed, the activation energy barrier for oxygen hydrogenation increases significantly, and the barrier for carbon hydrogenation is reduced. These effects make the formate reaction pathway more favorable than CO. Experimentally, we then carry out CO 2 reduction in highly concentrated potassium hydroxide (KOH), limiting the hydronium concentration in the aqueous electrolyte. The product selectivity of a silver catalyst switches from entirely CO under neutral conditions to over 50% formate in the alkaline environment. The simulated and experimentally observed selectivity shift provides new insights into the role of hydronium on CO 2 electroreduction processes and the ability for electrolyte manipulation to directly influence transition state (TS) kinetics, altering favored CO 2 reaction pathways. We argue that selectivity should be considered less of an intrinsic catalyst property, and rather a combined product of the catalyst and reaction environment.

A New Thickener for CO2 Anhydrous Fracturing Fluid

Directory of Open Access Journals (Sweden)

Zhang Jian

2015-01-01

Full Text Available CO2 dry fracturing technology is well-known for its advantages. Little water is used in this technology, which is able to ease the pressure of consumption on water resources. Many abroad theoretical researches, laboratory experiments and field tests have been taken to explore the yield mechanism, the adaptability and the technology of pure liquid CO2 fracturing. These achievements have been applied to a variety of reservoirs transformation and improven the effectiveness of stimulation treatment in a degree. The researches and studies in the domestic didn’t get popular until recent years. Thus, this article firstly introduces the main development and application about pure CO2 anhydrous fracturing technology, and sums up the effect and evaluation of its fluid through application examples both in the domestic and abroad. However, although this technology has many excellent qualities, but systematic studies indicate that its proppant-carrying capacity is less competitive because of the low viscosity of pure CO2 liquid and other reasons. In a consequence, it is necessary to develop an appropriate thickener for CO2 anhydrous fracturing fluid to improve its carrying capacity. Then this article describes some studies of previous scholars about CO2 thickener. Then we put forward our own research ideas and transform it into actual experiments. Thanks to the valid performances of these tests, we successfully develop a thickener X and cosolvent B.

Reduced suppression of CO2-induced ventilatory stimulation by endomorphins relative to morphine.

Science.gov (United States)

Czapla, Marc A; Zadina, James E

2005-10-19

Opioids are among the most effective analgesics, but a major limitation for their therapeutic usefulness is their induction of respiratory depression. Endomorphin-1 (EM1), in contrast to several other mu opioids, exhibits a threshold for respiratory depression that is well above its threshold for analgesia. Its effect on sensitivity to CO(2), however, remains unknown. Minute ventilation (V(E)) in 2, 4, and 6% CO(2) was measured before and after systemic administration of EM1, endomorphin-2 (EM2), DAMGO, and morphine in the conscious rat. EM1 and EM2 attenuated the hypercapnic ventilatory response (HCVR) only in high doses, while DAMGO and morphine diminished the HCVR in much lower doses. The ventilatory effects of high doses of all 4 agonists were blocked by the mu-opioid antagonist naloxone (0.4 mg/kg i.v.), but not by the peripherally restricted mu-opioid antagonist, methyl-naloxone (0.4 mg/kg i.v.). It was concluded that the endomorphins attenuated the HCVR only in large doses, well beyond the analgesic threshold, and did so through a centrally mediated mu-opioid mechanism.

Model analyses for sustainable energy supply under CO2 restrictions

International Nuclear Information System (INIS)

Matsuhashi, Ryuji; Ishitani, Hisashi.

1995-01-01

This paper aims at clarifying key points for realizing sustainable energy supply under restrictions on CO 2 emissions. For this purpose, possibility of solar breeding system is investigated as a key technology for the sustainable energy supply. The authors describe their mathematical model simulating global energy supply and demand in ultra-long term. Depletion of non-renewable resources and constraints on CO 2 emissions are taken into consideration in the model. Computed results have shown that present energy system based on non-renewable resources shifts to a system based on renewable resources in the ultra-long term with appropriate incentives

System thermodynamic performance comparison of CO2-EGS and water-EGS systems

International Nuclear Information System (INIS)

Zhang, Fu-Zhen; Jiang, Pei-Xue; Xu, Rui-Na

2013-01-01

CO 2 may be a better heat transmission fluid than water for Enhanced Geothermal Systems (EGS). The advantages and disadvantages of these two kinds of EGS are the focus of this study. The water and CO 2 -EGS system models including simple subsurface heat transfer and flow models and a surface energy conversion system model were designed based on the reservoir grade and the ambient temperatures. The results indicate that the operating parameters including the injection pressure, turbine outlet pressure and reservoir stimulated area should be optimized to match the actual CO 2 -EGS conditions. CO 2 -EGS produce more power than water-EGS for reservoirs with low recoverable thermal energies due to less irreversible losses compared to ORC or flash cycles for water-EGS. However, high resistance losses caused by high mass flow rates degrade the CO 2 -EGS performance; thus, the water-EGS has better performance than CO 2 -EGS for larger energy content reservoirs. -- Highlights: • Comparing the performance of CO 2 -EGS and water-EGS for various conditions. • Presenting the scope of applications for these two kinds of EGS systems. • Cooling after compression before the CO 2 is injected improves CO 2 -EGS performance. • There is an optimum recoverable thermal energy content for CO 2 -EGS

Final Report on "Rising CO2 and Long-term Carbon Storage in Terrestrial Ecosystems: An Empirical Carbon Budget Validation"

Energy Technology Data Exchange (ETDEWEB)

J. Patrick Megonigal; Bert G. Drake

2010-08-27

The primary goal of this report is to report the results of Grant DE-FG02-97ER62458, which began in 1997 as Grant DOE-98-59-MP-4 funded through the TECO program. However, this project has a longer history because DOE also funded this study from its inception in 1985 through 1997. The original grant was focused on plant responses to elevated CO2 in an intact ecosystem, while the latter grant was focused on belowground responses. Here we summarize the major findings across the 25 years this study has operated, and note that the experiment will continue to run through 2020 with NSF support. The major conclusions of the study to date are: (1 Elevated CO2 stimulated plant productivity in the C3 plant community by ~30% during the 25 year study. The magnitude of the increase in productivity varied interannually and was sometime absent altogether. There is some evidence of down-regulation at the ecosystem level across the 25 year record that may be due to interactions with other factors such as sea-level rise or long-term changes in N supply; (2) Elevated CO2 stimulated C4 productivity by <10%, perhaps due to more efficient water use, but C3 plants at elevated CO2 did not displace C4 plants as predicted; (3) Increased primary production caused a general stimulation of microbial processes, but there were both increases and decreases in activity depending on the specific organisms considered. An increase in methanogenesis and methane emissions implies elevated CO2 may amplify radiative forcing in the case of wetland ecosystems; (4) Elevated CO2 stimulated soil carbon sequestration in the form of an increase in elevation. The increase in elevation is 50-100% of the increase in net ecosystem production caused by elevated CO2 (still under analysis). The increase in soil elevation suggests the elevated CO2 may have a positive outcome for the ability of coastal wetlands to persist despite accelerated sea level rise; (5) Crossing elevated CO2 with elevated N causes the elevated CO

Elevated CO{sub 2} in a prototype free-air CO{sub 2} enrichment facility affects photosynthetic nitrogen relations in a maturing pine forest

Energy Technology Data Exchange (ETDEWEB)

Ellsworth, D.S.; LaRoche, J.; Hendrey, G.R.

1998-03-01

A maturing loblolly pine (Pinus taeda L.) forest was exposed to elevated CO{sub 2} in the natural environment in a perturbation study conducted over three seasons using the free-air CO{sub 2} enrichment (FACE) technique. At the time measurements were begun in this study, the pine canopy was comprised entirely of foliage which had developed under elevated CO{sub 2} conditions (atmospheric CO{sub 2} {approx} 550 {micro}mol/mol{sup {minus}1}). Measurements of leaf photosynthetic responses to CO{sub 2} were taken to examine the effects of elevated CO{sub 2} on photosynthetic N nutrition in a pine canopy under elevated CO{sub 2}. Photosynthetic CO{sub 2} response curves (A-c{sub i} curves) were similar in FACE trees under elevated CO{sub 2} compared with counterpart trees in ambient plots for the first foliage cohort produced in the second season of CO{sub 2} exposure, with changes in curve form detected in the foliage cohorts subsequently produced under elevated CO{sub 2}. Differences in the functional relationship between carboxylation rate and N{sub a} suggest that for a given N{sub a} allocated among successive cohorts of foliage in the upper canopy, V{sub c max} was 17% lower in FACE versus Ambient trees. The authors also found that foliar Rubisco content per unit total protein derived from Western blot analysis was lower in late-season foliage in FACE foliage compared with ambient-grown foliage. The results illustrate a potentially important mode of physiological adjustment to growth conditions that may operate in forest canopies. Findings suggest that mature loblolly pine trees growing in the field may have the capacity for shifts in intrinsic nitrogen utilization for photosynthesis under elevated CO{sub 2} that are not dependent on changes in leaf N. Findings suggest a need for continued examination of internal feedbacks at the whole-tree and ecosystem level in forests that may influence long-term photosynthetic responses to elevated CO{sub 2}.

CO2 dose–response functions for wheat grain, protein and mineral yield based on FACE and open-top chamber experiments

International Nuclear Information System (INIS)

Pleijel, Håkan; Högy, Petra

2015-01-01

Data from three Swedish open-top chamber and four German FACE experiments were combined to derive response functions for elevated CO 2 (eCO 2 ) effects on Cd, Zn, Mn, protein, grain yield, grain mass and grain number of wheat. Grain yield and grain number were increased by ∼6% and ∼7%, respectively, per 100 ppm CO 2 ; the former effect was linked to plant nitrogen status. Grain mass was not influenced by eCO 2 , whereas Cd concentration was reduced. Unlike Zn, Mn and protein, effects on Cd yield were not related to effects on grain yield. Yields of Mn, Zn and (weakly) protein were positively affected by eCO 2 . For protein, grain yield, grain mass and grain number, the results were consistent among the FACE and OTC experiments. A key conclusion was that yields of essential nutrients were enhanced (Mn > Zn > protein), although less than grain yield, which would not be expected from a simple dilution model. - Highlights: • Grain yield and grain number were positively affected by 6–7% per 100 ppm CO 2 . • Yield stimulation by CO 2 was influenced by plant nitrogen status. • Cd concentration was reduced by elevated CO 2 . • Yields of Zn, Mn and protein were stimulated by CO 2 , but less than grain yield. • A simple dilution model did not explain effects on Zn, Mn and protein. - Yields of Zn, Mn and protein were stimulated less by elevated CO 2 than grain yield, while Cd yield and grain mass were unaffected, in wheat exposed in FACE and open-top chambers

Panorama 2016 - Chemical recycling of CO2

International Nuclear Information System (INIS)

Forti, Laurent; Fosse, Florian

2015-12-01

The ongoing rise of atmospheric carbon dioxide concentration is a major environmental and societal concern. Among the potential solutions for reducing carbon emissions in the energy sector, the chemical recycling of CO 2 has received considerable attention. Conversion of carbon dioxide into other recoverable substances offers the benefit of reducing the carbon footprint of newly developed products and of shifting away from the use of fossil resources. Various methods to create a wide range of products are currently being studied. (authors)

Development of Low Cost Membranes (Ta, Nb & Cellulose Acetate) for H₂/CO₂ Separation in WGS Reactors

Energy Technology Data Exchange (ETDEWEB)

Seetala, Naidu [Grambling State Univ., LA (United States); Siriwardane, Upali [Louisiana Tech Univ., Ruston, LA (United States)

2011-12-15

The main aim of this work is to synthesize low temperature bimetallic nanocatalysts for Water Gas Shift reaction (WGS) for hydrogen production from CO and steam mixture; and develop low-cost metal (Nb/Ta)/ceramic membranes for H₂ separation and Cellulose Acetate membranes for CO₂ separation. .

In situ NMR observation of the lithium extraction/insertion from LiCoO2 cathode

International Nuclear Information System (INIS)

Shimoda, Keiji; Murakami, Miwa; Takamatsu, Daiko; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi

2013-01-01

Abstract: Rechargeable lithium-ion batteries (LIBs) are currently accepted to be one of the most suitable energy storage resources in portable electronic devices because of their high gravimetric and volumetric energy density. To understand the behavior of Li + ions on electrochemical lithium extraction/insertion process, we performed in situ 7 Li nuclear magnetic resonance (NMR) measurements for LiCoO 2 cathode in a plastic cell battery, and the spectral evolutions of the 7 Li NMR signal of Li x CoO 2 (0 ≤ x ≤ 1) were well investigated. Very narrow solid solution region of Li x CoO 2 (∼0.99 ≤ x 2 signal at ∼0 ppm, which is related to the localized nature of the electronic spin of paramagnetic Co 4+ ion formed at the very early delithiation stage. With further decreasing the signal intensity of LiCoO 2 , a Knight-shifted signal corresponding to an electrically conductive Li x CoO 2 phase emerged at x = 0.97, which then monotonously decreased in intensity for x x CoO 2 . These observations acquired in situ fully confirm the earlier studies obtained in ex situ measurements, although the present study offers more quantitative information. Moreover, it was shown that the peak position of the NMR shift for Li x CoO 2 moved as a function of lithium content, which behavior is analogous to the change in its c lattice parameter. Also, the growth and consumption of dendritic/mossy metallic lithium on the counter electrode was clearly observed during the charge/discharge cycles

Enhancing the smoothness of joint motion induced by functional electrical stimulation using co-activation strategies

Directory of Open Access Journals (Sweden)

Ruppel Mirjana

2017-09-01

Full Text Available The motor precision of today’s neuroprosthetic devices that use artificial generation of limb motion using Functional Electrical Stimulation (FES is generally low. We investigate the adoption of natural co-activation strategies as present in antagonistic muscle pairs aiming to improve motor precision produced by FES. In a test in which artificial knee-joint movements were generated, we could improve the smoothness of FES-induced motion by 513% when applying co-activation during the phases in which torque production is switched between muscles – compared to no co-activation. We further demonstrated how the co-activation level influences the joint stiffness in a pendulum test.

An in-situ IR study on the adsorption of CO2 and H2O on hydrotalcites

NARCIS (Netherlands)

Coenen, K.T.; Gallucci, F.; Mezari, B.; Hensen, E.J.M.; van Sint Annaland, M.

2018-01-01

In-situ IR technique was used to study the reversible adsorption of CO2 and H2O at elevated temperatures on a potassium-promoted hydrotalcite for its use in sorption-enhanced water-gas shift (SEWGS). It was found that mainly bidentate carbonate species are responsible for the reversible (cyclic)

Elevated atmospheric CO2 increases microbial growth rates and enzymes activity in soil

Science.gov (United States)

Blagodatskaya, Evgenia; Blagodatsky, Sergey; Dorodnikov, Maxim; Kuzyakov, Yakov

2010-05-01

Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO2 can cause a shift in the structure and activity of the microbial community responsible for the turnover of organic matter in soil. We investigated the long-term effect of elevated CO2 in the atmosphere on microbial biomass and specific growth rates in root-free and rhizosphere soil. The experiments were conducted under two free air carbon dioxide enrichment (FACE) systems: in Hohenheim and Braunschweig, as well as in the intensively managed forest mesocosm of the Biosphere 2 Laboratory (B2L) in Oracle, AZ. Specific microbial growth rates (μ) were determined using the substrate-induced respiration response after glucose and/or yeast extract addition to the soil. We evaluated the effect of elevated CO2 on b-glucosidase, chitinase, phosphatase, and sulfatase to estimate the potential enzyme activity after soil amendment with glucose and nutrients. For B2L and both FACE systems, up to 58% higher μ were observed under elevated vs. ambient CO2, depending on site, plant species and N fertilization. The μ-values increased linearly with atmospheric CO2 concentration at all three sites. The effect of elevated CO2 on rhizosphere microorganisms was plant dependent and increased for: Brassica napus=Triticum aestivumyeast extract then for those growing on glucose, i.e. the effect of elevated CO2 was smoothed on rich vs. simple substrate. So, the r/K strategies ratio can be better revealed by studying growth on simple (glucose) than on rich substrate mixtures (yeast extract). After adding glucose, enzyme activities under elevated CO2 were 1.2-1.9-fold higher than under ambient CO2. This indicates the increased activity of microorganisms, which leads to accelerated C turnover in soil under elevated CO2. Our results clearly showed that the functional characteristics of the soil microbial community (i.e. specific growth rates and enzymes activity) rather than total microbial biomass

Improved visible-light photocatalytic activity of TiO2 co-doped with copper and iodine

Science.gov (United States)

Dorraj, Masoumeh; Goh, Boon Tong; Sairi, Nor Asrina; Woi, Pei Meng; Basirun, Wan Jefrey

2018-05-01

Cu-I-co-doped TiO2 photocatalysts active to visible light absorption were prepared by hydrothermal method and calcined at various temperatures (350 °C, 450 °C, and 550 °C). The co-doped powders at 350 °C displayed the highest experimental Brunauer-Emmett-Teller surface area and lowest photoluminescence intensity, which demonstrated that a decrease in electron-hole recombination process. The synthesis of co-doped TiO2 was performed at this optimized temperature. In the co-doped sample, the Cu2+ doped TiO2 lattice created a major "red-shift" in the absorption edge due to the presence of the 3d Cu states, whereas the amount of red-shift from the I5+ doping in the TiO2 lattice was minor. Interestingly, the presence of Cu2+ species also boosted the reduction of I5+ ions to the lower multi-valance state I- in the TiO2 lattice by trapping the photogenerated electrons, which resulted in effective separation of the photogenerated charges. The Cu-I-co-doped TiO2 was able to degrade methyl orange dye under visible-light irradiation with improved photocatalytic activity compared with the single metal-doped TiO2 and pure TiO2 because of the strong visible light absorption and effective separation of photogenerated charges caused by the synergistic effects of Cu and I co-dopants.

Reactions of laser-ablated iron atoms and cations with carbon monoxide: Infrared spectra of FeCO+, Fe(CO)2+, Fe(CO)x, and Fe(CO)x- (x=1-4) in solid neon

Science.gov (United States)

Zhou, Mingfei; Andrews, Lester

1999-06-01

Laser-ablated iron atoms, cations, and electrons have been reacted with CO molecules during condensation in excess neon. The FeCO molecule is observed at 1933.7 cm-1 in solid neon. Based on isotopic shifts and density functional calculations, the FeCO molecule has the same 3Σ- ground state in solid neon that has been observed at 1946.5 cm-1 in a recent high resolution gas phase investigation [Tanaka et al., J. Chem. Phys. 106, 2118 (1997)]. The C-O stretching vibration of the Fe(CO)2 molecule is observed at 1917.1 cm-1 in solid neon, which is in excellent agreement with the 1928.2 cm-1 gas phase value for the linear molecule. Anions and cations are also produced and trapped, absorptions at 1782.0, 1732.9, 1794.5, and 1859.7 cm-1 are assigned to the linear FeCO-, Fe(CO)2-, trigonal planar Fe(CO)3-, and C3v Fe(CO)4- anions, respectively, and 2123.0, 2134.0 cm-1 absorptions to the linear FeCO+ and Fe(CO)2+ cations. Doping these experiments with CCl4 virtually eliminates the anion absorptions and markedly increases the cation absorptions, which confirms the charge identifications. Higher iron carbonyl Fe(CO)3, Fe(CO)4, and Fe(CO)5 absorptions are produced on photolysis.

Geological storage of CO2

International Nuclear Information System (INIS)

Czernichowski-Lauriol, I.

2005-01-01

The industrial storage of CO 2 is comprised of three steps: - capture of CO 2 where it is produced (power plants, cement plants, etc.); - transport (pipe lines or boats); - storage, mainly underground, called geological sequestration... Three types of reservoirs are considered: - salted deep aquifers - they offer the biggest storage capacity; - exhausted oil and gas fields; - non-exploited deep coal mine streams. The two latter storage types may allow the recovery of sellable products, which partially or totally offsets the storage costs. This process is largely used in the petroleum industry to improve the productivity of an oil field, and is called FOR (Enhanced Oil Recovery). A similar process is applied in the coal mining industry to recover the imprisoned gas, and is called ECBM (Enhanced Coal Bed methane). Two storage operations have been initiated in Norway and in Canada, as well as research programmes in Europe, North America, Australia and Japan. International organisations to stimulate this technology have been created such as the 'Carbon Sequestration Leadership Forum' and 'the Intergovernmental Group for Climate Change'. This technology will be taken into account in the instruments provided by the Tokyo Protocol. (author)

Ruthenium and osmium carbonyl nitrosyl complexes: Matrix infrared spectra and density functional calculations for M(CO){sub 2}(NO){sub 2} and M(CO)(NO) (M = Ru, Os)

Energy Technology Data Exchange (ETDEWEB)

Song, Zhenjun [Department of Chemistry, Tongji University, Shanghai 200092 (China); Wang, Xuefeng, E-mail: xfwang@tongji.edu.cn [Department of Chemistry, Tongji University, Shanghai 200092 (China); Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University (China)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Laser-ablated ruthenium or osmium atom reactions with CO and NO mixtures in solid argon. Black-Right-Pointing-Pointer Metal carbonyl nitrosyls including M(CO)(NO) and 18-electron configuration M(CO){sub 2}(NO){sub 2} molecules (M = Ru, Os). Black-Right-Pointing-Pointer The observed absorption bands of reaction products are identified by isotopic substitution and DFT calculations. Black-Right-Pointing-Pointer The bonding and reaction mechanism are discussed in detail. -- Abstract: Laser-ablated ruthenium or osmium atom reactions with CO and NO mixtures in solid argon produce unsaturated metal carbonyl nitrosyls including M(CO)(NO) and 18-electron configuration M(CO){sub 2}(NO){sub 2} molecules (M = Ru, Os). The observed absorption bands of reaction products are identified by isotopic substitution, isotopic ratios and isotopic distributions ({sup 13}CO, {sup 15}NO, and mixtures). DFT (B3LYP and BP86) vibrational fundamental calculations reproduce observed frequencies and isotopic shifts very well. The bonding and reaction mechanism are discussed.

Practical use of chemical shift databases for protein solid-state NMR: 2D chemical shift maps and amino-acid assignment with secondary-structure information

Energy Technology Data Exchange (ETDEWEB)

Fritzsching, K. J.; Yang, Y.; Schmidt-Rohr, K.; Hong Mei, E-mail: mhong@iastate.edu [Iowa State University, Department of Chemistry (United States)

2013-06-15

We introduce a Python-based program that utilizes the large database of {sup 13}C and {sup 15}N chemical shifts in the Biological Magnetic Resonance Bank to rapidly predict the amino acid type and secondary structure from correlated chemical shifts. The program, called PACSYlite Unified Query (PLUQ), is designed to help assign peaks obtained from 2D {sup 13}C-{sup 13}C, {sup 15}N-{sup 13}C, or 3D {sup 15}N-{sup 13}C-{sup 13}C magic-angle-spinning correlation spectra. We show secondary-structure specific 2D {sup 13}C-{sup 13}C correlation maps of all twenty amino acids, constructed from a chemical shift database of 262,209 residues. The maps reveal interesting conformation-dependent chemical shift distributions and facilitate searching of correlation peaks during amino-acid type assignment. Based on these correlations, PLUQ outputs the most likely amino acid types and the associated secondary structures from inputs of experimental chemical shifts. We test the assignment accuracy using four high-quality protein structures. Based on only the C{alpha} and C{beta} chemical shifts, the highest-ranked PLUQ assignments were 40-60 % correct in both the amino-acid type and the secondary structure. For three input chemical shifts (CO-C{alpha}-C{beta} or N-C{alpha}-C{beta}), the first-ranked assignments were correct for 60 % of the residues, while within the top three predictions, the correct assignments were found for 80 % of the residues. PLUQ and the chemical shift maps are expected to be useful at the first stage of sequential assignment, for combination with automated sequential assignment programs, and for highly disordered proteins for which secondary structure analysis is the main goal of structure determination.

Density functional theory study on water-gas-shift reaction over molybdenum disulfide

DEFF Research Database (Denmark)

Shi, X. R.; Wang, Shengguang; Hu, J.

2009-01-01

. The pathway for water-gas-shift reaction on both terminations has been carefully studied where the most favorable reaction path precedes the redox mechanism, namely the reaction takes place as follows: CO + H2O --> CO + OH + H --> CO + O + 2H --> CO2 + H-2. The most likely reaction candidates for the formate......Density functional theory calculations have been carried out to investigate the adsorption of reaction intermediates appearing during water-gas-shift reaction at the sulfur covered MoS2 (1 0 0)surfaces, Mo-termination with 37.5% S coverage and S-termination with 50% S coverage using periodic slabs...... species HCOO formation is the surface CO2 reaction with H as a side reaction of CO2 desorption on S-termination with 50% S coverage. The formed HCOO species will react further with adsorbed hydrogen yielding H2COO followed by breaking its C-O bond to form the surface CH2O and O species....

An econometric time-series analysis of global CO2 concentrations and emissions

International Nuclear Information System (INIS)

Cohen, B.C.; Labys, W.C.; Eliste, P.

2001-01-01

This paper extends previous work on the econometric modelling of CO 2 concentrations and emissions. The importance of such work rests in the fact that models of the Cohen-Labys variety represent the only alternative to scientific or physical models of CO 2 accumulations whose parameters are inferred rather than estimated. The stimulation for this study derives from the recent discovery of oscillations and cycles in the net biospheric flux of CO 2 . A variety of time series tests is thus used to search for the presence of normality, stationarity, cyclicality and stochastic processes in global CO 2 emissions and concentrations series. Given the evidence for cyclicality of a short-run nature in the spectra of these series, both structural time series and error correction model are applied to confirm the frequency and amplitude of these cycles. Our results suggest new possibilities for determining equilibrium levels of CO 2 concentrations and subsequently revising stabilization policies. (Author)

A readout system for the wavelength-shifting optical module

Energy Technology Data Exchange (ETDEWEB)

Foesig, Carl-Christian; Boeser, Sebastian [Johannes Gutenberg-Universitaet, Mainz (Germany); Collaboration: IceCube-Collaboration

2016-07-01

The success of IceCube and the plans for an IceCube-Gen2 stimulate the development of new photo sensors. The approach of the Wavelength-shifting Optical Module is to provide a device which has a low dark noise rate combined with a high detection efficiency. A small PMT is used to detect red shifted photons guided in a coated PMMA tube, originally emitted by a wavelength shifting coating that absorbs photons in the UV Region. We have studied several PMTs for their usability with the IceCube-Gen2 readout system. Relevant parameters are the pulse widths in relation to the bandwidth of the IceCube-Gen2 readout electronics and the dark noise rates.

Effects of elevated CO2, warming and drought episodes on plant carbon uptake in a temperate heath ecosystem are controlled by soil water status

DEFF Research Database (Denmark)

Albert, Kristian Rost; Ro-Poulsen, H.; Mikkelsen, Teis Nørgaard

2011-01-01

The impact of elevated CO2, periodic drought and warming on photosynthesis and leaf characteristics of the evergreen dwarf shrub Calluna vulgaris in a temperate heath ecosystem was investigated. Photosynthesis was reduced by drought in midsummer and increased by elevated CO2 throughout the growing...... season, whereas warming only stimulated photosynthesis early in the year. At the beginning and end of the growing season, a T × CO2 interaction synergistically stimulated plant carbon uptake in the combination of warming and elevated CO2. At peak drought, the D × CO2 interaction antagonistically down......-regulated photosynthesis, suggesting a limited ability of elevated CO2 to counteract the negative effect of drought. The response of photosynthesis in the full factorial combination (TDCO2) could be explained by the main effect of experimental treatments (T, D, CO2) and the two-factor interactions (D × CO2, T × CO2...

Acclimation of the summer annual species, lolium temulentum, to CO(2) enrichment

Science.gov (United States)

Lewis; Peratoner; Cairns; Causton; Foyer

1999-11-01

Lolium temulentum L. Ba 3081 was grown hydroponically in air (350 &mgr;mol mol(-1) CO(2)) and elevated CO(2) (700 &mgr;mol mol(-1) CO(2)) at two irradiances (150 and 500 &mgr;mol m(-2) s(-1)) for 35 days at which point the plants were harvested. Elevated CO(2) did not modify relative growth rate or biomass at either irradiance. Foliar carbon-to-nitrogen ratios were decreased at elevated CO(2) and plants had a greater number of shorter tillers, particularly at the lower growth irradiance. Both light-limited and light-saturated rates of photosynthesis were stimulated. The amount of ribulose-1, 5-bisphosphate carboxylase-oxygenase (Rubisco) protein was increased at elevated CO(2), but maximum extractable Rubisco activities were not significantly increased. A pronounced decrease in the Rubisco activation state was found with CO(2) enrichment, particularly at the higher growth irradiance. Elevated-CO(2)-induced changes in leaf carbohydrate composition were small in comparison to those caused by changes in irradiance. No CO(2)-dependent effects on fructan biosynthesis were observed. Leaf respiration rates were increased by 68% in plants grown with CO(2) enrichment and low light. We conclude that high CO(2) will only result in increased biomass if total light input favourably increases the photosynthesis-to-respiration ratio. At low irradiances, biomass is more limited by increased rates of respiration than by CO(2)-induced enhancement of photosynthesis.

Monitoring CO2 gas-phase migration in a shallow sand aquifer using cross-borehole ground penetrating radar

DEFF Research Database (Denmark)

Lassen, Rune Nørbæk; Sonnenborg, T.O.; Jensen, Karsten Høgh

2015-01-01

and transversely to the groundwater flow direction. As the injection continued, the main flow direction of the gaseous CO2 shifted and CO2 gas pockets with a gas saturation of up to 0.3 formed below lower-permeable sand layers. CO2 gas was detected in a GPR-panel 5 m away from the injection point after 21 h...... of leakage from a CCS site, and that even small changes in the formation texture can create barriers for the CO2 migration....

Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.

Science.gov (United States)

Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

2015-01-01

Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P

Effects of high CO2 on growth and metabolism of Arabidopsis seedlings during growth with a constantly limited supply of nitrogen.

Science.gov (United States)

Takatani, Nobuyuki; Ito, Takuro; Kiba, Takatoshi; Mori, Marie; Miyamoto, Tetsuro; Maeda, Shin-Ichi; Omata, Tatsuo

2014-02-01

Elevated CO2 has been reported to stimulate plant growth under nitrogen-sufficient conditions, but the effects of CO2 on growth in a constantly nitrogen-limited state, which is relevant to most natural habitats of plants, remain unclear. Here, we maintained Arabidopsis seedlings under such conditions by growing a mutant with reduced nitrate uptake activity on a medium containing nitrate as the sole nitrogen source. Under nitrogen-sufficient conditions (i.e. in the presence of ammonium), growth of shoots and roots of both the wild type (WT) and the mutant was increased approximately 2-fold by elevated CO2. Growth stimulation of shoots and roots by elevated CO2 was observed in the WT growing with nitrate as the sole nitrogen source, but in the mutant grown with nitrate, the high-CO2 conditions stimulated only the growth of roots. In the mutant, elevated CO2 caused well-known symptoms of nitrogen-starved plants, including decreased shoot/root ratio, reduced nitrate content and accumulation of anthocyanin, but also had an increased Chl content in the shoot, which was contradictory to the known effect of nitrogen depletion. A high-CO2-responsive change specific to the mutant was not observed in the levels of the major metabolites, although CO2 responses were observed in the WT and the mutant. These results indicated that elevated CO2 causes nitrogen limitation in the seedlings grown with a constantly limited supply of nitrogen, but the Chl content and the root biomass of the plant increase to enhance the activities of both photosynthesis and nitrogen uptake, while maintaining normal metabolism and response to high CO2.

Model-based analysis of CO2 revalorization for di-methyl ether synthesis driven by solar catalytic reforming

International Nuclear Information System (INIS)

Luu, Minh Tri; Milani, Dia; Sharma, Manish; Zeaiter, Joseph; Abbas, Ali

2016-01-01

Highlights: • Solar energy applied for synthesis of di-methyl ether via dry methane reforming. • Concentrated solar energy at receiver reaction zone for syngas generation. • H 2 /CO molar ratio of ‘1’ is maintained via two alternative processing routes. • Assessed three days of operation under different insolation levels. • Improvements of 18.7%, 32.2% and 20% for methane, energy and CO 2 emission intensities. - Abstract: The application of solar energy is investigated for the synthesis of di-methyl ether (DME) in a solar irradiated dry methane reformer (DMR). Solar radiations are concentrated onto a receiver and distributed to the reaction zone to provide necessary energy for syngas (CO and H 2 ) generation. In order to maintain a H 2 /CO molar ratio of ‘1’, as required in DME synthesis, the produced syngas is processed via two alternative routes: solar reformer coupled in parallel with a non-solar reformer (SoR-NSoR) and solar reformer integrated with a water-gas shift reactor (SoR-WGS). It is found that steam methane reforming (SMR) is the most suitable methodology when coupled with a solar reformer due to high H 2 content in the SMR syngas. Further performance analysis is conducted by simulating three days of operation under different insolation levels (high, medium and low irradiations). The simulation results showed that the SoR-WGS configuration produces the highest improvements of 18.7%, 32.2% and 20% in terms of methane, energy and CO 2 emission intensity respectively. This enhanced process performance originates from the exothermic nature of the WGS process which helps in controlling the overall syngas composition, whereas the SoR-NSoR requires fossil based thermal energy to drive the NSoR process to similar control targets. This promising improvement of all metrics in SoR-WGS may stimulate in-depth techno-economic feasibility of this unique solar integration for DME and other synthetic fuels production.

Impact of elevated CO2 concentration on dynamics of leaf photosynthesis in Fagus sylvatica is modulated by sky conditions.

Science.gov (United States)

Urban, Otmar; Klem, Karel; Holišová, Petra; Šigut, Ladislav; Šprtová, Mirka; Teslová-Navrátilová, Petra; Zitová, Martina; Špunda, Vladimír; Marek, Michal V; Grace, John

2014-02-01

It has been suggested that atmospheric CO2 concentration and frequency of cloud cover will increase in future. It remains unclear, however, how elevated CO2 influences photosynthesis under complex clear versus cloudy sky conditions. Accordingly, diurnal changes in photosynthetic responses among beech trees grown at ambient (AC) and doubled (EC) CO2 concentrations were studied under contrasting sky conditions. EC stimulated the daily sum of fixed CO2 and light use efficiency under clear sky. Meanwhile, both these parameters were reduced under cloudy sky as compared with AC treatment. Reduction in photosynthesis rate under cloudy sky was particularly associated with EC-stimulated, xanthophyll-dependent thermal dissipation of absorbed light energy. Under clear sky, a pronounced afternoon depression of CO2 assimilation rate was found in sun-adapted leaves under EC compared with AC conditions. This was caused in particular by stomata closure mediated by vapour pressure deficit. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Adsorption and Photodesorption of CO from Charged Point Defects on TiO ₂ (110)

Energy Technology Data Exchange (ETDEWEB)

Mu, Rentao; Dahal, Arjun P.; Wang, Zhitao; Dohnalek, Zdenek; Kimmel, Gregory A.; Petrik, Nikolay G.; Lyubinetsky, Igor V.

2017-09-12

Adsorption and photodesorption of weakly-bound carbon monoxide, CO, from reduced and hydroxylated rutile TiO2(110) (r- and h- TiO2(110)) at sub-monolayer coverages is studied with atomically-resolved scanning tunneling microscopy (STM) along with ensemble-averaged temperature-programmed desorption (TPD) and angle-resolved photon-stimulated desorption (PSD) at low temperatures ( 50 K). STM data weighted by the concentration of each kind of adsorption sites on r-TiO2(110) give an adsorption probability which is the highest for the bridging oxygen vacancies (VO) and very low for the Ti5c sites closest to VO. Occupancy of the remaining Ti5c sites with CO is significant, but smaller than for VO. The probability distribution for the different adsorption sites corresponds to a very small difference in CO adsorption energies: < 0.02 eV. We also find that UV irradiation stimulates both diffusion and desorption of CO at low temperature. CO photodesorbs primarily from the vacancies with a bi-modal angular distribution. In addition to a major, normal to the surface component, there is a broader cosine component indicating scattering from the surface which likely also leads to photo-stimulated diffusion. Hydroxylation of VO’s does not significantly change the CO PSD yield and angular distribution, indicating that not atomic but rather electronic surface defects are involved in the site-specific PSD process. We suggest that photodesorption can be initiated by recombination of photo-generated holes with excess unpaired electrons localized near the surface point-defect (either VO or bridging hydroxyl), leading to the surface atoms rearrangement and ejection of the weakly-bound CO molecules.

Enhanced CO_2 capture on graphene via N, S dual-doping

International Nuclear Information System (INIS)

Li, Jieyuan; Hou, Meiling; Chen, Yanqiu; Cen, Wanglai; Chu, Yinghao; Yin, Shi

2017-01-01

Highlights: • Sluggish conjugated π bonds of graphene should be weakened to promote adsorption activity. • A charge delivery channel along S → N → CO_2 path should be prior responsible for the enhancement of CO_2 capture on graphene. • Applicative temperature range of graphene-based adsorbents for CO_2 capture is extend to about 100 °C via N, S dual-doping. - Abstract: N, S doped graphene-based materials have been recently recognized as promising adsorbents for CO_2 capture, but understanding of the adsorption mechanism at the atomic level is still limited. Herein, the local structures and promotion mechanism of CO_2 capture by N, S doped graphene were investigated by combining density functional theory and ab initio thermodynamics. A single vacancy defected graphene involving N, S dual-doping was found to be a superior adsorbent for CO_2 capture under mild conditions (<100 °C, 1 atm). The enhanced CO_2 adsorption performance should be ascribed to a charge delivery channel along the S → N → CO_2 path, leading to extra charge transfer from graphene to CO_2. It is worth mentioning that the extra charge transfer was stimulated by the unique sp"2 hybridization of pyridine N and further enhanced by S in N, S dual-doped graphene. A possible mechanism has been proposed to explain the high adsorption performance of CO_2 by N, S dual-doped graphene, which offers insights for the design of new graphene-based adsorbents.

Synthesis of oxocarbon-encapsulated gold nanoparticles with blue-shifted localized surface plasmon resonance by pulsed laser ablation in water with CO2 absorbers

Science.gov (United States)

Del Rosso, T.; Rey, N. A.; Rosado, T.; Landi, S.; Larrude, D. G.; Romani, E. C.; Freire Junior, F. L.; Quinteiro, S. M.; Cremona, M.; Aucelio, R. Q.; Margheri, G.; Pandoli, O.

2016-06-01

Colloidal suspensions of oxocarbon-encapsulated gold nanoparticles have been synthesized in a one-step procedure by pulsed-laser ablation (PLA) at 532 nm of a solid gold target placed in aqueous solution containing CO2 absorbers, but without any stabilizing agent. Multi-wavelength surface enhanced Raman spectroscopy allows the identification of adsorbed amorphous carbon and graphite, Au-carbonyl, Au coordinated CO2-derived bicarbonates/carbonates and hydroxyl groups around the AuNPs core. Scanning electron microscopy, energy dispersive x-ray analysis and high resolution transmission electron microscopy highlight the organic shell structure around the crystalline metal core. The stability of the colloidal solution of nanocomposites (NCs) seems to be driven by solvation forces and is achieved only in neutral or basic pH using monovalent hydroxide counter-ions (NaOH, KOH). The NCs are characterized by a blue shift of the localized surface plasmon resonance (LSPR) band typical of metal-ligand stabilization by terminal π-back bonding, attributed to a core charging effect caused by Au-carbonyls. Total organic carbon measurements detect the final content of organic carbon in the colloidal solution of NCs that is about six times higher than the value of the water solution used to perform PLA. The colloidal dispersions of NCs are stable for months and are applied as analytical probes in amino glycoside antibiotic LSPR based sensing.

Spring photosynthetic recovery of boreal Norway spruce under conditions of elevated [CO(2)] and air temperature.

Science.gov (United States)

Wallin, Göran; Hall, Marianne; Slaney, Michelle; Räntfors, Mats; Medhurst, Jane; Linder, Sune

2013-11-01

Accumulated carbon uptake, apparent quantum yield (AQY) and light-saturated net CO2 assimilation (Asat) were used to assess the responses of photosynthesis to environmental conditions during spring for three consecutive years. Whole-tree chambers were used to expose 40-year-old field-grown Norway spruce trees in northern Sweden to an elevated atmospheric CO2 concentration, [CO2], of 700 μmol CO2 mol(-1) (CE) and an air temperature (T) between 2.8 and 5.6 °C above ambient T (TE), during summer and winter. Net shoot CO2 exchange (Anet) was measured continuously on 1-year-old shoots and was used to calculate the accumulated carbon uptake and daily Asat and AQY. The accumulated carbon uptake, from 1 March to 30 June, was stimulated by 33, 44 and 61% when trees were exposed to CE, TE, and CE and TE combined, respectively. Air temperature strongly influenced the timing and extent of photosynthetic recovery expressed as AQY and Asat during the spring. Under elevated T (TE), the recovery of AQY and Asat commenced ∼10 days earlier and the activity of these parameters was significantly higher throughout the recovery period. In the absence of frost events, the photosynthetic recovery period was less than a week. However, frost events during spring slowed recovery so that full recovery could take up to 60 days to complete. Elevated [CO2] stimulated AQY and Asat on average by ∼10 and ∼50%, respectively, throughout the recovery period, but had minimal or no effect on the onset and length of the photosynthetic recovery period during the spring. However, AQY, Asat and Anet all recovered at significantly higher T (average +2.2 °C) in TE than in TA, possibly caused by acclimation or by shorter days and lower light levels during the early part of the recovery in TE compared with TA. The results suggest that predicted future climate changes will cause prominent stimulation of photosynthetic CO2 uptake in boreal Norway spruce forest during spring, mainly caused by elevated T

Molecular properties of metal difluorides and their interactions with CO2 and H2O molecules: a DFT investigation.

Science.gov (United States)

Arokiyanathan, Agnes Lincy; Lakshmipathi, Senthilkumar

2017-11-18

A computational study of metal difluorides (MF 2 ; M = Ca to Zn) and their interactions with carbon dioxide and water molecules was performed. The structural parameter values obtained and the results of AIM analysis and energy decomposition analysis indicated that the Ca-F bond is weaker and less ionic than the bonds in the transition metal difluorides. A deformation density plot revealed the stablizing influence of the Jahn-Teller effect in nonlinear MF 2 molecules (e.g., where M= Sc, Ti, Cr). An anaysis of the metal K-edge peaks of the difluorides showed that shifts in the edge energy were due to the combined effects of the ionicity, effective nuclear charge, and the spin state of the metal. The interactions of CO 2 with ScF 2 (Scc3 geometry) and TiF 2 (Tic2 geometry) caused CO 2 to shift from its usual linear geometry to a bent geometry (η 2 (C=O) binding mode), while it retained its linear geometry (η 1 (O) binding mode) when it interacted with the other metal difluorides. Energy decomposition analysis showed that, among the various geometries considered, the Scc3 and Tic2 geometries possessed the highest interaction energies and orbital interaction energies. Heavier transition metal difluorides showed stronger affinities for H 2 O, whereas the lighter transition metal (Sc and Ti) difluorides preferred CO 2 . Overall, the results of this study suggest that fluorides of lighter transition metals with partially filled d orbitals (e.g., Sc and Ti) could be used for CO 2 capture under moist conditions. Graphical abstract Interaction of metal difluorides with carbon dioxide and water.

Beneficial effects of CO2 enrichment to field-grown soybeans under ozone stress

International Nuclear Information System (INIS)

Lee, E.H.; Mulchi, C.L.

1991-01-01

Damage from gaseous air pollution [e.g. ozone (O 3 ) and sulfur dioxide (SO 2 )] on crops in the US has been estimated to exceed several billion dollars annually. Atmospheric carbon dioxide (CO 2 ) concentrations have increased from about 290 ppm in the late 1800's to current levels of 350 ppm. The combined effects of increased CO 2 and O 3 stress have not been studied under field conditions. The present study was conducted to determine the interactive effects of CO 2 enrichment and O 3 stress on the growth and physiology of 'Clark' soybean, testing the hypothesis that elevated CO 2 will ameliorate the effects of O 3 stress. Experiments with soybeans in open-top field chambers showed that increasing CO 2 levels to 400 parts per million (ppm) negated current ambient ozone harmful effects on soybean yields. When ambient O 3 levels were doubled, it was necessary to increase the atmospheric CO 2 concentration to 500 ppm to negate O 3 damage. Rising CO 2 counteracts O 3 pollution. Reduced stomatal conductance and decreased photosynthesis appear to reverse the CO 2 stimulation

Interactive effects of elevated CO2, warming, and drought on photosynthesis of Deschampsia flexuosa in a temperate heath ecosystem

DEFF Research Database (Denmark)

Albert, Kristian Rost; Ro-Poulsen, H.; Mikkelsen, Teis Nørgaard

2011-01-01

Global change factors affect plant carbon uptake in concert. In order to investigate the response directions and potential interactive effects, and to understand the underlying mechanisms, multifactor experiments are needed. The focus of this study was on the photosynthetic response to elevated CO2...... not decrease gs, but stimulated Pn via increased Ci. The T×CO2 synergistically increased plant carbon uptake via photosynthetic capacity up-regulation in early season and by better access to water after rewetting. The effects of the combination of drought and elevated CO2 depended on soil water availability......, with additive effects when the soil water content was low and D×CO2 synergistic stimulation of Pn after rewetting. The photosynthetic responses appeared to be highly influenced by growth pattern. The grass has opportunistic water consumption, and a biphasic growth pattern allowing for leaf dieback at low soil...

Influence of ocean acidification on plankton community structure during a winter-to-summer succession: An imaging approach indicates that copepods can benefit from elevated CO2 via indirect food web effects

Science.gov (United States)

Taucher, Jan; Haunost, Mathias; Boxhammer, Tim; Bach, Lennart T.; Algueró-Muñiz, María; Riebesell, Ulf

2017-01-01

Plankton communities play a key role in the marine food web and are expected to be highly sensitive to ongoing environmental change. Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. These changes–summarized by the term ocean acidification (OA)–can significantly affect the physiology of planktonic organisms. However, studies on the response of entire plankton communities to OA, which also include indirect effects via food-web interactions, are still relatively rare. Thus, it is presently unclear how OA could affect the functioning of entire ecosystems and biogeochemical element cycles. In this study, we report from a long-term in situ mesocosm experiment, where we investigated the response of natural plankton communities in temperate waters (Gullmarfjord, Sweden) to elevated CO2 concentrations and OA as expected for the end of the century (~760 μatm pCO2). Based on a plankton-imaging approach, we examined size structure, community composition and food web characteristics of the whole plankton assemblage, ranging from picoplankton to mesozooplankton, during an entire winter-to-summer succession. The plankton imaging system revealed pronounced temporal changes in the size structure of the copepod community over the course of the plankton bloom. The observed shift towards smaller individuals resulted in an overall decrease of copepod biomass by 25%, despite increasing numerical abundances. Furthermore, we observed distinct effects of elevated CO2 on biomass and size structure of the entire plankton community. Notably, the biomass of copepods, dominated by Pseudocalanus acuspes, displayed a tendency towards elevated biomass by up to 30–40% under simulated ocean acidification. This effect was significant for certain copepod size classes and was most likely driven by CO2-stimulated responses of primary producers and a complex interplay of trophic interactions that allowed this

Economic evaluation of pre-combustion CO2-capture in IGCC power plants by porous ceramic membranes

International Nuclear Information System (INIS)

Franz, Johannes; Maas, Pascal; Scherer, Viktor

2014-01-01

Highlights: • Process simulations of IGCC with pre-combustion capture via membranes were done. • Most promising technology is the water–gas-shift-membrane-reactor (WGSMR). • Energetic evaluations showed minimum efficiency loss of 5.8%-points for WGSMR. • Economic evaluations identified boundary limits of membrane technology. • Cost of electricity for optimum WGSMR-case is 57 €/MW h under made assumptions. - Abstract: Pre-combustion-carbon-capture is one of the three main routes for the mitigation of CO 2 -emissions by fossil fueled power plants. Based on the data of a detailed technical evaluation of CO 2 -capture by porous ceramic membranes (CM) and ceramic membrane reactors (WGSMR) in an Integrated-Gasification-Combined-Cycle (IGCC) power plant this paper focuses on the economic effects of CO 2 -abatement. First the results of the process simulations are presented briefly. The analysis is based on a comparison with a reference IGCC without CO 2 -capture (dry syngas cooling, bituminous coal, efficiency of 47.4%). In addition, as a second reference, an IGCC process with CO 2 removal based on standard Selexol-scrubbing is taken into account. The most promising technology for CO 2 -capture by membranes in IGCC applications is the combination of a water gas shift reactor and a H 2 -selective membrane into one water gas shift membrane reactor. For the WGSRM-case efficiency losses can be limited to about 6%-points (including losses for CO 2 compression) for a CO 2 separation degree of 90%. This is a severe reduction of the efficiency loss compared to Selexol (10.3% points) or IGCC–CM (8.6% points). The economic evaluation is based on a detailed analysis of investment and operational costs. Parameters like membrane costs and lifetime, costs of CO 2 -certificates and annual operating hours are taken into account. The purpose of these evaluations is to identify the minimum cost of electricity for the different capture cases for the variation of the boundary

ELEVATED CO{sub 2} IN A PROTOTYPE FREE-AIR CO{sub 2} ENRICHMENT FACILITY AFFECTS PHOTOSYNTHETIC NITROGEN RELATIONS IN A MATURING PINE FOREST

Energy Technology Data Exchange (ETDEWEB)

ELLSWORTH,D.S.; LA ROCHE,J.; HENDREY,G.R.

1998-03-01

A maturing loblolly pine (Pinus taeda L.) forest was exposed to elevated CO{sub 2} in the natural environment in a perturbation study conducted over three seasons using the free-air CO{sub 2} enrichment (FACE) technique. At the time measurements were begun in this study, the pine canopy was comprised entirely of foliage which had developed under elevated CO{sub 2} conditions (atmospheric [CO{sub 2}] {approx} 550 {micro}mol mol{sup {minus}1}). Measurements of leaf photosynthetic responses to CO{sub 2} were taken to examine the effects of elevated CO{sub 2} on photosynthetic N nutrition in a pine canopy under elevated CO{sub 2}. Photosynthetic CO{sub 2} response curves (A-c{sub i} curves) were similar in FACE trees under elevated CO{sub 2} compared with counterpart trees in ambient plots for the first foliage cohort produced in the second season of CO{sub 2} exposure, with changes in curve form detected in the foliage cohorts subsequently produced under elevated CO{sub 2}. Differences in the functional relationship between carboxylation rate and N{sub a} suggest that for a given N{sub a} allocated among successive cohorts of foliage in the upper canopy, V{sub c max} was 17% lower in FACE versus Ambient trees. The authors also found that foliar Rubisco content per unit total protein derived from Western blot analysis was lower in late-season foliage in FACE foliage compared with ambient-grown foliage. The results illustrate a potentially important mode of physiological adjustment to growth conditions that may operate in forest canopies. Their findings suggest that mature loblolly pine trees growing in the field may have the capacity for shifts in intrinsic nitrogen utilization for photosynthesis under elevated CO{sub 2} that are not dependent on changes in leaf N. While carboxylation efficiency per unit N apparently decreased under elevated CO{sub 2}, photosynthetic rates in trees at elevated CO{sub 2} concentrations {approx} 550 pmol mol{sub {minus}1} are still

Experimental observation of parametric effects near period doubling in a loss-modulated CO2 laser

OpenAIRE

Chizhevsky, V. N.

1996-01-01

A number of parametric effects, such as suppression of period doubling, shift of the bifurcation point, scaling law relating the shift and the perturbation amplitude, influence of the detuning on the suppression, reaching of the maximum gain between the original and shifted bifurcation points, and scaling law for idler power are experimentally observed near period doubling bifurcation in a loss-driven CO2 laser that is subjected to periodic loss perturbations at a frequency that is close to a...

Effects of elevated CO2 and nitrogen deposition on ecosystem carbon fluxes on the Sanjiang plain wetland in Northeast China.

Science.gov (United States)

Wang, Jianbo; Zhu, Tingcheng; Ni, Hongwei; Zhong, Haixiu; Fu, Xiaoling; Wang, Jifeng

2013-01-01

Increasing atmospheric CO2 and nitrogen (N) deposition across the globe may affect ecosystem CO2 exchanges and ecosystem carbon cycles. Additionally, it remains unknown how increased N deposition and N addition will alter the effects of elevated CO2 on wetland ecosystem carbon fluxes. Beginning in 2010, a paired, nested manipulative experimental design was used in a temperate wetland of northeastern China. The primary factor was elevated CO2, accomplished using Open Top Chambers, and N supplied as NH4NO3 was the secondary factor. Gross primary productivity (GPP) was higher than ecosystem respiration (ER), leading to net carbon uptake (measured by net ecosystem CO2 exchange, or NEE) in all four treatments over the growing season. However, their magnitude had interannual variations, which coincided with air temperature in the early growing season, with the soil temperature and with the vegetation cover. Elevated CO2 significantly enhanced GPP and ER but overall reduced NEE because the stimulation caused by the elevated CO2 had a greater impact on ER than on GPP. The addition of N stimulated ecosystem C fluxes in both years and ameliorated the negative impact of elevated CO2 on NEE. In this ecosystem, future elevated CO2 may favor carbon sequestration when coupled with increasing nitrogen deposition.

Response to elevated CO2 in the temperate C3 grass Festuca arundinaceae across ten soil orders

Directory of Open Access Journals (Sweden)

Eric A Nord

2015-02-01

Full Text Available Soils vary widely in mineral nutrient availability and physical characteristics, but the influence of this variability on plant responses to elevated CO2 remains poorly understood. As a first approximation of the effect of global soil variability on plant growth response to CO2, we evaluated the effect of CO2 on tall fescue (Festuca arundinacea grown in soils representing 10 of the 12 global soil orders plus a high-fertility control. Plants were grown in small pots in continuously stirred reactor tanks in a greenhouse. Elevated CO2 (800 ppm increased plant biomass in the high-fertility control and in two of the more fertile soils. Elevated CO2 had variable effects on foliar mineral concentration - nitrogen was not altered by elevated CO2, and phosphorus and potassium were only affected by CO2 in a small number of soils. While leaf photosynthesis was stimulated by elevated CO2 in six soils, canopy photosynthesis was not stimulated. Four principle components were identified; the first was associated with foliar minerals and soil clay, and the second with soil acidity and foliar manganese concentration. The third principle component was associated with gas exchange, and the fourth with plant biomass and soil minerals. Soils in which tall fescue did not respond to elevated CO2 account for 83% of global land area. These results show that variation in soil physical and chemical properties have important implications for plant responses to global change, and highlight the need to consider soil variability in models of vegetation response to global change.

Improving yield potential in crops under elevated CO(2): Integrating the photosynthetic and nitrogen utilization efficiencies.

Science.gov (United States)

Kant, Surya; Seneweera, Saman; Rodin, Joakim; Materne, Michael; Burch, David; Rothstein, Steven J; Spangenberg, German

2012-01-01

Increasing crop productivity to meet burgeoning human food demand is challenging under changing environmental conditions. Since industrial revolution atmospheric CO(2) levels have linearly increased. Developing crop varieties with increased utilization of CO(2) for photosynthesis is an urgent requirement to cope with the irreversible rise of atmospheric CO(2) and achieve higher food production. The primary effects of elevated CO(2) levels in most crop plants, particularly C(3) plants, include increased biomass accumulation, although initial stimulation of net photosynthesis rate is only temporal and plants fail to sustain the maximal stimulation, a phenomenon known as photosynthesis acclimation. Despite this acclimation, grain yield is known to marginally increase under elevated CO(2). The yield potential of C(3) crops is limited by their capacity to exploit sufficient carbon. The "C fertilization" through elevated CO(2) levels could potentially be used for substantial yield increase. Rubisco is the rate-limiting enzyme in photosynthesis and its activity is largely affected by atmospheric CO(2) and nitrogen availability. In addition, maintenance of the C/N ratio is pivotal for various growth and development processes in plants governing yield and seed quality. For maximizing the benefits of elevated CO(2), raising plant nitrogen pools will be necessary as part of maintaining an optimal C/N balance. In this review, we discuss potential causes for the stagnation in yield increases under elevated CO(2) levels and explore possibilities to overcome this limitation by improved photosynthetic capacity and enhanced nitrogen use efficiency. Opportunities of engineering nitrogen uptake, assimilatory, and responsive genes are also discussed that could ensure optimal nitrogen allocation toward expanding source and sink tissues. This might avert photosynthetic acclimation partially or completely and drive for improved crop production under elevated CO(2) levels.

Improving yield potential in crops under elevated CO2: Integrating the photosynthetic and nitrogen utilization efficiencies

Science.gov (United States)

Kant, Surya; Seneweera, Saman; Rodin, Joakim; Materne, Michael; Burch, David; Rothstein, Steven J.; Spangenberg, German

2012-01-01

Increasing crop productivity to meet burgeoning human food demand is challenging under changing environmental conditions. Since industrial revolution atmospheric CO2 levels have linearly increased. Developing crop varieties with increased utilization of CO2 for photosynthesis is an urgent requirement to cope with the irreversible rise of atmospheric CO2 and achieve higher food production. The primary effects of elevated CO2 levels in most crop plants, particularly C3 plants, include increased biomass accumulation, although initial stimulation of net photosynthesis rate is only temporal and plants fail to sustain the maximal stimulation, a phenomenon known as photosynthesis acclimation. Despite this acclimation, grain yield is known to marginally increase under elevated CO2. The yield potential of C3 crops is limited by their capacity to exploit sufficient carbon. The “C fertilization” through elevated CO2 levels could potentially be used for substantial yield increase. Rubisco is the rate-limiting enzyme in photosynthesis and its activity is largely affected by atmospheric CO2 and nitrogen availability. In addition, maintenance of the C/N ratio is pivotal for various growth and development processes in plants governing yield and seed quality. For maximizing the benefits of elevated CO2, raising plant nitrogen pools will be necessary as part of maintaining an optimal C/N balance. In this review, we discuss potential causes for the stagnation in yield increases under elevated CO2 levels and explore possibilities to overcome this limitation by improved photosynthetic capacity and enhanced nitrogen use efficiency. Opportunities of engineering nitrogen uptake, assimilatory, and responsive genes are also discussed that could ensure optimal nitrogen allocation toward expanding source and sink tissues. This might avert photosynthetic acclimation partially or completely and drive for improved crop production under elevated CO2 levels. PMID:22833749

Muscle fiber type specific induction of slow myosin heavy chain 2 gene expression by electrical stimulation

International Nuclear Information System (INIS)

Crew, Jennifer R.; Falzari, Kanakeshwari; DiMario, Joseph X.

2010-01-01

Vertebrate skeletal muscle fiber types are defined by a broad array of differentially expressed contractile and metabolic protein genes. The mechanisms that establish and maintain these different fiber types vary throughout development and with changing functional demand. Chicken skeletal muscle fibers can be generally categorized as fast and fast/slow based on expression of the slow myosin heavy chain 2 (MyHC2) gene in fast/slow muscle fibers. To investigate the cellular and molecular mechanisms that control fiber type formation in secondary or fetal muscle fibers, myoblasts from the fast pectoralis major (PM) and fast/slow medial adductor (MA) muscles were isolated, allowed to differentiate in vitro, and electrically stimulated. MA muscle fibers were induced to express the slow MyHC2 gene by electrical stimulation, whereas PM muscle fibers did not express the slow MyHC2 gene under identical stimulation conditions. However, PM muscle fibers did express the slow MyHC2 gene when electrical stimulation was combined with inhibition of inositol triphosphate receptor (IP3R) activity. Electrical stimulation was sufficient to increase nuclear localization of expressed nuclear-factor-of-activated-T-cells (NFAT), NFAT-mediated transcription, and slow MyHC2 promoter activity in MA muscle fibers. In contrast, both electrical stimulation and inhibitors of IP3R activity were required for these effects in PM muscle fibers. Electrical stimulation also increased levels of peroxisome-proliferator-activated receptor-γ co-activator-1 (PGC-1α) protein in PM and MA muscle fibers. These results indicate that MA muscle fibers can be induced by electrical stimulation to express the slow MyHC2 gene and that fast PM muscle fibers are refractory to stimulation-induced slow MyHC2 gene expression due to fast PM muscle fiber specific cellular mechanisms involving IP3R activity.

Evaluation of Dry Sorbent Injection Technology for Pre-Combustion CO{sub 2} Capture

Energy Technology Data Exchange (ETDEWEB)

Richardson, Carl [URS Group, Inc., Austin, TX (United States); Steen, William [URS Group, Inc., Austin, TX (United States); Triana, Eugenio [URS Group, Inc., Austin, TX (United States); Machalek, Thomas [URS Group, Inc., Austin, TX (United States); Davila, Jenny [URS Group, Inc., Austin, TX (United States); Schmit, Claire [URS Group, Inc., Austin, TX (United States); Wang, Andrew [URS Group, Inc., Austin, TX (United States); Temple, Brian [URS Group, Inc., Austin, TX (United States); Lu, Yongqi [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States); Lu, Hong [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States); Zhang, Luzheng [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States); Ruhter, David [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States); Rostam-Abadi, Massoud [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States); Sayyah, Maryam [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States); Ito, Brandon [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States); Suslick, Kenneth [Illinois State Geological Survey - University of Illinois at Urbana-Champaign (United States)

2013-09-30

This document summarizes the work performed on Cooperative Agreement DE-FE0000465, “Evaluation of Dry Sorbent Technology for Pre-Combustion CO{sub 2} Capture,” during the period of performance of January 1, 2010 through September 30, 2013. This project involves the development of a novel technology that combines a dry sorbent-based carbon capture process with the water-gas-shift reaction for separating CO{sub 2} from syngas. The project objectives were to model, develop, synthesize and screen sorbents for CO{sub 2} capture from gasified coal streams. The project was funded by the DOE National Energy Technology Laboratory with URS as the prime contractor. Illinois Clean Coal Institute and The University of Illinois Urbana-Champaign were project co-funders. The objectives of this project were to identify and evaluate sorbent materials and concepts that were suitable for capturing carbon dioxide (CO{sub 2}) from warm/hot water-gas-shift (WGS) systems under conditions that minimize energy penalties and provide continuous gas flow to advanced synthesis gas combustion and processing systems. Objectives included identifying and evaluating sorbents that efficiently capture CO{sub 2} from a gas stream containing CO{sub 2}, carbon monoxide (CO), and hydrogen (H{sub 2}) at temperatures as high as 650 °C and pressures of 400-600 psi. After capturing the CO{sub 2}, the sorbents would ideally be regenerated using steam, or other condensable purge vapors. Results from the adsorption and regeneration testing were used to determine an optimal design scheme for a sorbent enhanced water gas shift (SEWGS) process and evaluate the technical and economic viability of the dry sorbent approach for CO{sub 2} capture. Project work included computational modeling, which was performed to identify key sorbent properties for the SEWGS process. Thermodynamic modeling was used to identify optimal physical properties for sorbents and helped down-select from the universe of possible sorbent

Experimental Ion Mobility measurements in Ne-CO$_2$ and CO$_2$-N$_2$ mixtures

CERN Document Server

Encarnação, P.M.C.C.; Veenhof, R.; Neves, P.N.B.; Santos, F.P.; Trindade, A.M.F.; Borges, F.I.G.M.; Conde, C.A.N.

2016-01-01

In this paper we present the experimental results for the mobility, K0, of ions in neon-carbon dioxide (Ne-CO2) and carbon dioxide-nitrogen (CO2-N2) gaseous mixtures for total pressures ranging from 8–12 Torr, reduced electric fields in the 10–25 Td range, at room temperature. Regarding the Ne-CO2 mixture only one peak was observed for CO2 concentrations above 25%, which has been identified as an ion originated in CO2, while below 25% of CO2 a second-small peak appears at the left side of the main peak, which has been attributed to impurities. The mobility values for the main peak range between 3.51 ± 0.05 and 1.07 ± 0.01 cm2V−1s−1 in the 10%-99% interval of CO2, and from 4.61 ± 0.19 to 3.00 ± 0.09 cm2V−1s−1 for the second peak observed (10%–25% of CO2). For the CO2-N2, the time-of-arrival spectra displayed only one peak for CO2 concentrations above 10%, which was attributed to ions originated in CO2, namely CO2+(CO2), with a second peak appearing for CO2 concentrations below 10%. This secon...

Using the Moist Static Energy Budget to Understand Storm Track Shifts across a Range of Timescales

Science.gov (United States)

Barpanda, P.; Shaw, T.

2017-12-01

Storm tracks shift meridionally in response to forcing across a range of time scales. Here we formulate a moist static energy (MSE) framework for storm track position and use it to understand storm track shifts in response to seasonal insolation, El Niño minus La Niña conditions, and direct (increased CO2 over land) and indirect (increased sea surface temperature) effects of increased CO2. Two methods (linearized Taylor series and imposed MSE flux divergence) are developed to quantify storm track shifts and decompose them into contributions from net energy (MSE input to the atmosphere minus atmospheric storage) and MSE flux divergence by the mean meridional circulation and stationary eddies. Net energy is not a dominant contribution across the time scales considered. The stationary eddy contribution dominates the storm-track shift in response to seasonal insolation, El Niño minus La Niña conditions, and CO2 direct effect in the Northern Hemisphere, whereas the mean meridional circulation contribution dominates the shift in response to CO2 indirect effect during northern winter and in the Southern Hemisphere during May and October. Overall, the MSE framework shows the seasonal storm-track shift in the Northern Hemisphere is connected to the stationary eddy MSE flux evolution. Furthermore, the equatorward storm-track shift during northern winter in response to El Niño minus La Niña conditions involves a different regime than the poleward shift in response to increased CO2 even though the tropical upper troposphere warms in both cases.

Electro-tactile stimulation of the posterior neck induces body anteropulsion during upright stance.

Science.gov (United States)

De Nunzio, A M; Yavuz, U S; Martinez-Valdes, E; Farina, D; Falla, D

2018-05-01

Sensory information conveyed along afferent fibers from muscle and joint proprioceptors play an important role in the control of posture and gait in humans. In particular, proprioceptive information from the neck is fundamental in supplying the central nervous system with information about the orientation and movement of the head relative to the rest of the body. The previous studies have confirmed that proprioceptive afferences originating from the neck region, evoked via muscle vibration, lead to strong body-orienting effects during static conditions (e.g., leaning of the body forwards or backwards, depending on location of vibration). However, it is not yet certain in humans, whether the somatosensory receptors located in the deep skin (cutaneous mechanoreceptors) have a substantive contribution to postural control, as vibratory stimulation encompasses the receptive field of all the somatosensory receptors from the skin to the muscles. The aim of this study was to investigate the postural effect of cutaneous mechanoreceptor afferences using electro-tactile stimulation applied to the neck. Ten healthy volunteers (8M, 2F) were evaluated. The average position of their centre of foot pressure (CoP) was acquired before, during, and after a subtle electro-tactile stimulation over their posterior neck (mean ± SD = 5.1 ± 2.3 mA at 100 Hz-140% of the perception threshold) during upright stance with their eyes closed. The electro-tactile stimulation led to a body-orienting effect with the subjects consistently leaning forward. An average shift of the CoP of 12.1 ± 11.9 mm (mean ± SD) was reported, which significantly (p < 0.05) differed from its average position under a control condition (no stimulation). These results indicate that cutaneous mechanoreceptive inflow from the neck is integrated to control stance. The findings are relevant for the exploitation of electro-tactile stimulation for rehabilitation interventions where induced

Rechargeable Al-CO2 Batteries for Reversible Utilization of CO2.

Science.gov (United States)

Ma, Wenqing; Liu, Xizheng; Li, Chao; Yin, Huiming; Xi, Wei; Liu, Ruirui; He, Guang; Zhao, Xian; Luo, Jun; Ding, Yi

2018-05-21

The excessive emission of CO 2 and the energy crisis are two major issues facing humanity. Thus, the electrochemical reduction of CO 2 and its utilization in metal-CO 2 batteries have attracted wide attention because the batteries can simultaneously accelerate CO 2 fixation/utilization and energy storage/release. Here, rechargeable Al-CO 2 batteries are proposed and realized, which use chemically stable Al as the anode. The batteries display small discharge/charge voltage gaps down to 0.091 V and high energy efficiencies up to 87.7%, indicating an efficient battery performance. Their chemical reaction mechanism to produce the performance is revealed to be 4Al + 9CO 2 ↔ 2Al 2 (CO 3 ) 3 + 3C, by which CO 2 is reversibly utilized. These batteries are envisaged to effectively and safely serve as a potential CO 2 fixation/utilization strategy with stable Al. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Does a decade of elevated [CO2] affect a desert perennial plant community?

Science.gov (United States)

Newingham, Beth A; Vanier, Cheryl H; Kelly, Lauren J; Charlet, Therese N; Smith, Stanley D

2014-01-01

Understanding the effects of elevated [CO2 ] on plant community structure is crucial to predicting ecosystem responses to global change. Early predictions suggested that productivity in deserts would increase via enhanced water-use efficiency under elevated [CO2], but the response of intact arid plant communities to elevated [CO2 ] is largely unknown. We measured changes in perennial plant community characteristics (cover, species richness and diversity) after 10 yr of elevated [CO2] exposure in an intact Mojave Desert community at the Nevada Desert Free-Air CO2 Enrichment (FACE) Facility. Contrary to expectations, total cover, species richness, and diversity were not affected by elevated [CO2]. Over the course of the experiment, elevated [CO2] had no effect on changes in cover of the evergreen C3 shrub, Larrea tridentata; alleviated decreases in cover of the C4 bunchgrass, Pleuraphis rigida; and slightly reduced the cover of C3 drought-deciduous shrubs. Thus, we generally found no effect of elevated [CO2] on plant communities in this arid ecosystem. Extended drought, slow plant growth rates, and highly episodic germination and recruitment of new individuals explain the lack of strong perennial plant community shifts after a decade of elevated [CO2]. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Impacts of CO2 Enrichment on Productivity and Light Requirements of Eelgrass.

Science.gov (United States)

Zimmerman, R. C.; Kohrs, D. G.; Steller, D. L.; Alberte, R. S.

1997-10-01

Seagrasses, although well adapted for submerged existence, are CO2-limited and photosynthetically inefficient in seawater. This leads to high light requirements for growth and survival and makes seagrasses vulnerable to light limitation. We explored the long-term impact of increased CO2 availability on light requirements, productivity, and C allocation in eelgrass (Zostera marina L.). Enrichment of seawater CO2 increased photosynthesis 3-fold, but had no long-term impact on respiration. By tripling the rate of light-saturated photosynthesis, CO2 enrichment reduced the daily period of irradiance-saturated photosynthesis (Hsat) that is required for the maintenance of positive whole-plant C balance from 7 to 2.7 h, allowing plants maintained under 4 h of Hsat to perform like plants growing in unenriched seawater with 12 h of Hsat. Eelgrass grown under 4 h of Hsat without added CO2 consumed internal C reserves as photosynthesis rates and chlorophyll levels dropped. Growth ceased after 30 d. Leaf photosynthesis, respiration, chlorophyll, and sucrose-phosphate synthase activity of CO2-enriched plants showed no acclimation to prolonged enrichment. Thus, the CO2-stimulated improvement in photosynthesis reduced light requirements in the long term, suggesting that globally increasing CO2 may enhance seagrass survival in eutrophic coastal waters, where populations have been devastated by algal proliferation and reduced water-column light transparency.

Low doses of glyphosate enhance growth, CO2 assimilation, stomatal conductance and transpiration in sugarcane and eucalyptus.

Science.gov (United States)

Nascentes, Renan F; Carbonari, Caio A; Simões, Plinio S; Brunelli, Marcela C; Velini, Edivaldo D; Duke, Stephen O

2018-05-01

Sublethal doses of herbicides can enhance plant growth and stimulate other process, an effect known as hormesis. The magnitude of hormesis is dependent on the plant species, the herbicide and its dose, plant development stage and environmental parameters. Glyphosate hormesis is well established, but relatively little is known of the mechanism of this phenomenon. The objective of this study was to determine if low doses of glyphosate that cause growth stimulation in sugarcane and eucalyptus concomitantly stimulate CO 2 assimilation. Shoot dry weight in both species increased at both 40 and 60 days after application of 6.2 to 20.2 g a.e. ha -1 glyphosate. The level of enhanced shoot dry weight was 11 to 37%, depending on the time after treatment and the species. Concomitantly, CO 2 assimilation, stomatal conductance and transpiration were increased by glyphosate doses similar to those that caused growth increases. Glyphosate applied at low doses increased the dry weight of sugarcane and eucalyptus plants in all experiments. This hormetic effect was related to low dose effects on CO 2 assimilation rate, stomatal conductance and transpiration rate, indicating that low glyphosate doses enhance photosynthesis of plants. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Sea anemones may thrive in a high CO2 world.

Science.gov (United States)

Suggett, David J; Hall-Spencer, Jason M; Rodolfo-Metalpa, Riccardo; Boatman, Toby G; Payton, Ross; Tye Pettay, D; Johnson, Vivienne R; Warner, Mark E; Lawson, Tracy

2012-10-01

Increased seawater pCO 2 , and in turn 'ocean acidification' (OA), is predicted to profoundly impact marine ecosystem diversity and function this century. Much research has already focussed on calcifying reef-forming corals (Class: Anthozoa) that appear particularly susceptible to OA via reduced net calcification. However, here we show that OA-like conditions can simultaneously enhance the ecological success of non-calcifying anthozoans, which not only play key ecological and biogeochemical roles in present day benthic ecosystems but also represent a model organism should calcifying anthozoans exist as less calcified (soft-bodied) forms in future oceans. Increased growth (abundance and size) of the sea anemone (Anemonia viridis) population was observed along a natural CO 2 gradient at Vulcano, Italy. Both gross photosynthesis (P G ) and respiration (R) increased with pCO 2 indicating that the increased growth was, at least in part, fuelled by bottom up (CO 2 stimulation) of metabolism. The increase of P G outweighed that of R and the genetic identity of the symbiotic microalgae (Symbiodinium spp.) remained unchanged (type A19) suggesting proximity to the vent site relieved CO 2 limitation of the anemones' symbiotic microalgal population. Our observations of enhanced productivity with pCO 2 , which are consistent with previous reports for some calcifying corals, convey an increase in fitness that may enable non-calcifying anthozoans to thrive in future environments, i.e. higher seawater pCO 2 . Understanding how CO 2 -enhanced productivity of non- (and less-) calcifying anthozoans applies more widely to tropical ecosystems is a priority where such organisms can dominate benthic ecosystems, in particular following localized anthropogenic stress. © 2012 Blackwell Publishing Ltd.

Out-of-equilibrium nanocrystalline R1-s(Fe,M)5+2s alloys (R=Sm,Pr; M=Co,Si,Ga)

International Nuclear Information System (INIS)

Bessais, L.; Djega-Mariadassou, C.

2005-01-01

The out-of-equilibrium hexagonal P6/mmm R 1-s (Fe,M) 5+2s (R=Sm,Pr and M=Co, Si or Ga) intermetallics are obtained by controlled nanocrystallization. A model is presented to explain the structure of the hexagonal phases, which stoichiometry is consistent with Sm(Fe,M) 9 and R(Fe,Ti,Co) 10 . The Curie temperatures increase versus Ga, Si, Co content. The analysis of the Moessbauer spectra leads to monotonous variation of the hyperfine parameters. The refinement of the Moessbauer spectra was performed on the basis of the correlation between Wigner-Seitz cell volumes obtained from X-ray diffraction results and isomer shifts. The abundance of each magnetic site was calculated by the multinomial distribution law. For a given substituting Co, Si, Ga content, the sequence for the isomer shift in the hexagonal cell is 2e>3g>6l. With increasing M content, the isomer shift of the 3g site remains quasi-constant. Those approaches lead to the location of Si, Ga, Co in 3g site, Ti in 6l site. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Infrared spectra and stability of CO and H2O sorption over Ag-exchanged ZSM-5 zeolite: DFT study

International Nuclear Information System (INIS)

Jiang Shujun; Huang Shiping; Tu Weixia; Zhu Jiqin

2009-01-01

The infrared spectra and stability of CO and H 2 O sorption over Ag-exchanged ZSM-5 zeolite were investigated by using density function theory (DFT). The changes of NBO charge show that the electron transfers from CO molecule to the Ag + cation to form an σ-bond, and it accompanies by the back donation of d-electrons from Ag + cation to the CO (π*) orbital as one and two CO molecules are adsorbed on Ag-ZSM-5. The free energy changes ΔG, -5.55 kcal/mol and 6.52 kcal/mol for one and two CO molecules, illustrate that the Ag + (CO) 2 complex is unstable at the room temperature. The vibration frequency of C-O stretching of one CO molecule bonded to Ag + ion at 2211 cm -1 is in good agreement with the experimental results. The calculated C-O symmetric and antisymmetric stretching frequencies in the Ag + (CO) 2 complex shift to 2231 cm -1 and 2205 cm -1 when the second CO molecule is adsorbed. The calculated C-O stretching frequency in CO-Ag-ZSM-5-H 2 O complex shifts to 2199 cm -1 , the symmetric and antisymmetric O-H stretching frequencies are 3390 cm -1 and 3869 cm -1 , respectively. The Gibbs free energy change (ΔG H 2 O ) is -6.58 kcal/mol as a H 2 O molecule is adsorbed on CO-Ag-ZSM-5 complex at 298 K. The results show that CO-Ag-ZSM-5-H 2 O complex is more stable at room temperature

Potential Improvements of Supercritical Recompression CO2 Brayton Cycle Coupled with KALIMER-600 by Modifying Critical Point of CO2

International Nuclear Information System (INIS)

Jeong, Woo Seok; Lee, Jeong Ik; Jeong, Yong Hoon; No, Hee Cheon

2010-01-01

Most of the existing designs of a Sodium cooled Fast Reactor (SFR) have a Rankine cycle as an electric power generation cycle. This has the risk of a sodium water reaction. To prevent any hazards from a sodium water reaction, an indirect Brayton cycle using Supercritical Carbon dioxide (S-CO 2 ) as the working fluids for a SFR is an alternative approach to improve the current SFR design. The supercritical Brayton cycle is defined as a cycle with operating conditions above the critical point and the main compressor inlet condition located slightly above the critical point of working fluid. This is because the main advantage of the cycle comes from significantly decreased compressor work just above the critical point due to high density near boundary between supercritical state and subcritical state. For this reason, the minimum temperature and pressure of cycle are just above the CO 2 critical point. In other words, the critical point acts as a limitation of the lowest operating condition of the cycle. In general, lowering the minimum temperature of a thermodynamic cycle can increase the efficiency and the minimum temperature can be decreased by shifting the critical point of CO 2 as mixed with other gases. In this paper, potential enhancement of S-CO 2 cycle coupled with KALIMER-600, which has been developed at KAERI, was investigated using a developed cycle code with a gas mixture property program

Case study on ground surface deformation induced by CO2 injection into coal seam

International Nuclear Information System (INIS)

Li Hong; Tang Chun'an

2010-01-01

To monitor a geomechanical response of injecting CO 2 into relatively shallow coal seams, tiltmeters were set as an array to cover the ground surface area surrounding the injection well, and to measure the ground deformation during a well fracturing stimulation and a short-term CO 2 injection test. In this paper, an attempt to establish a quantitative relationship between the in-situ coal swelling and the corresponding ground deformation was made by means of numerical simulation study. (authors)

Influence of root-bed size on the response of tobacco to elevated CO2 as mediated by cytokinins

Science.gov (United States)

Schaz, Ulrike; Düll, Barbara; Reinbothe, Christiane; Beck, Erwin

2014-01-01

The extent of growth stimulation of C3 plants by elevated CO2 is modulated by environmental factors. Under optimized environmental conditions (high light, continuous water and nutrient supply, and others), we analysed the effect of an elevated CO2 atmosphere (700 ppm, EC) and the importance of root-bed size on the growth of tobacco. Biomass production was consistently higher under EC. However, the stimulation was overridden by root-bed volumes that restricted root growth. Maximum growth and biomass production were obtained at a root bed of 15 L at ambient and elevated CO2 concentrations. Starting with seed germination, the plants were strictly maintained under ambient or elevated CO2 until flowering. Thus, the well-known acclimation effect of growth to enhanced CO2 did not occur. The relative growth rates of EC plants exceeded those of ambient-CO2 plants only during the initial phases of germination and seedling establishment. This was sufficient for a persistently higher absolute biomass production by EC plants in non-limiting root-bed volumes. Both the size of the root bed and the CO2 concentration influenced the quantitative cytokinin patterns, particularly in the meristematic tissues of shoots, but to a smaller extent in stems, leaves and roots. In spite of the generally low cytokinin concentrations in roots, the amounts of cytokinins moving from the root to the shoot were substantially higher in high-CO2 plants. Because the cytokinin patterns of the (xylem) fluid in the stems did not match those of the shoot meristems, it is assumed that cytokinins as long-distance signals from the roots stimulate meristematic activity in the shoot apex and the sink leaves. Subsequently, the meristems are able to synthesize those phytohormones that are required for the cell cycle. Root-borne cytokinins entering the shoot appear to be one of the major control points for the integration of various environmental cues into one signal for optimized growth. PMID:24790131

Acclimation of Arabidopsis thaliana to long-term CO{sub 2} enrichment and nitrogen supply is basically a matter of growth rate adjustment

Energy Technology Data Exchange (ETDEWEB)

Tocquin, P.; Ormenese, S.; Pieltain, A.; Detry, N.; Bernier, G.; Perilleux, C. [Univ. of Liege, Dept. of Life Sciences, Lab. of Plant Physiology, Liege (Belgium)

2006-12-15

The long-term response of Arabidopsis thaliana to increasing CO{sub 2} was evaluated in plants grown in 800 {mu}l l{sup -1} CO{sub 2} from sowing and maintained, in hydroponics, on three nitrogen supplies: 'low', 'medium' and 'high'. The global response to high CO{sub 2} and N-supply was evaluated by measuring growth parameters in parallel with photosynthetic activity, leaf carbohydrates, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) messenger RNA and protein, stomatal conductance (g-s) and density. CO{sub 2} enrichment was found to stimulate biomass production, whatever the N-supply. This stimulation was transient on low N-supply and persisted throughout the whole vegetative growth only in high N-supply. Acclimation on low N-high C0{sub 2} was not associated with carbohydrate accumulation or with a strong reduction in Rubisco amount or activity. At high N-supply, growth stimulation by high CO{sub 2} was mainly because of the acceleration of leaf production and expansion while other parameters such as specific leaf area, root/shoot ratio and g{sub s} appeared to be correlated with total leaf area. Our results thus suggest that, in strictly controlled and stable growing conditions, acclimation of A. thaliana to long-term CO{sub 2} enrichment is mostly controlled by growth rate adjustment. (au)

CO2 sequestration

International Nuclear Information System (INIS)

Favre, E.; Jammes, L.; Guyot, F.; Prinzhofer, A.; Le Thiez, P.

2009-01-01

This document presents the summary of a conference-debate held at the Academie des Sciences (Paris, France) on the topic of CO 2 sequestration. Five papers are reviewed: problems and solutions for the CO 2 sequestration; observation and surveillance of reservoirs; genesis of carbonates and geological storage of CO 2 ; CO 2 sequestration in volcanic and ultra-basic rocks; CO 2 sequestration, transport and geological storage: scientific and economical perspectives

Can elevated CO2 and ozone shift the genetic composition of aspen (Populus tremuloides) stands? New Phytologist

Science.gov (United States)

Emily V. Moran; Mark E. Kubiske

2013-01-01

The world's forests are currently exposed to increasing concentrations of carbon dioxide (CO2) and ozone (O3). Both pollutants can potentially exert a selective effect on plant populations. This, in turn, may lead to changes in ecosystem properties, such as carbon sequestration. Here, we report how elevated CO

Effects of elevated CO2 and nitrogen deposition on ecosystem carbon fluxes on the Sanjiang plain wetland in Northeast China.

Directory of Open Access Journals (Sweden)

Jianbo Wang

Full Text Available BACKGROUND: Increasing atmospheric CO2 and nitrogen (N deposition across the globe may affect ecosystem CO2 exchanges and ecosystem carbon cycles. Additionally, it remains unknown how increased N deposition and N addition will alter the effects of elevated CO2 on wetland ecosystem carbon fluxes. METHODOLOGY/PRINCIPAL FINDINGS: Beginning in 2010, a paired, nested manipulative experimental design was used in a temperate wetland of northeastern China. The primary factor was elevated CO2, accomplished using Open Top Chambers, and N supplied as NH4NO3 was the secondary factor. Gross primary productivity (GPP was higher than ecosystem respiration (ER, leading to net carbon uptake (measured by net ecosystem CO2 exchange, or NEE in all four treatments over the growing season. However, their magnitude had interannual variations, which coincided with air temperature in the early growing season, with the soil temperature and with the vegetation cover. Elevated CO2 significantly enhanced GPP and ER but overall reduced NEE because the stimulation caused by the elevated CO2 had a greater impact on ER than on GPP. The addition of N stimulated ecosystem C fluxes in both years and ameliorated the negative impact of elevated CO2 on NEE. CONCLUSION/SIGNIFICANCE: In this ecosystem, future elevated CO2 may favor carbon sequestration when coupled with increasing nitrogen deposition.

The structural, electronic and magnetic properties of CoS2 under pressure

Science.gov (United States)

Feng, Zhong-Ying; Yang, Yan; Zhang, Jian-Min

2018-05-01

The structural, electronic and magnetic properties of CoS2 under pressure have been investigated by the first-principles calculations. The lattice constant and volume decrease with increasing pressure. The CoS2 is stable and behaves a brittle characteristic under the pressures of 0-5 GPa. The CoS2 presents metallic characteristic under the pressures of 1-5 GPa although it is nearly half-metal (HM) under the pressure of 0 GPa. The lowest conduction bands for spin-up and spin-down channels shift towards higher and lower energy region, respectively, with the pressure increasing from 0 to 5 GPa. In spin-up channel the conduction band minimum (CBM) is mainly contributed by Co-3d(eg) orbitals at R point but the valence band maximum (VBM) is contributed by Co-3d(t2g) orbitals near M point. While in spin-down channel the CBM is contributed by S-3p orbitals at Γ point but the VBM is contributed by Co-3d(t2g) orbitals near X point. The CoS2 is still suitable to be used in the supercapacitor under the environmental pressures of 0-5 GPa due to the high conductivity.

Hematopoietic stem cell cytokines and fibroblast growth factor-2 stimulate human endothelial cell-pericyte tube co-assembly in 3D fibrin matrices under serum-free defined conditions.

Directory of Open Access Journals (Sweden)

Annie O Smith

Full Text Available We describe a novel 3D fibrin matrix model using recombinant hematopoietic stem cell cytokines under serum-free defined conditions which promotes the assembly of human endothelial cell (EC tubes with co-associated pericytes. Individual ECs and pericytes are randomly mixed together and EC tubes form that is accompanied by pericyte recruitment to the EC tube abluminal surface over a 3-5 day period. These morphogenic processes are stimulated by a combination of the hematopoietic stem cell cytokines, stem cell factor, interleukin-3, stromal derived factor-1α, and Flt-3 ligand which are added in conjunction with fibroblast growth factor (FGF-2 into the fibrin matrix. In contrast, this tube morphogenic response does not occur under serum-free defined conditions when VEGF and FGF-2 are added together in the fibrin matrices. We recently demonstrated that VEGF and FGF-2 are able to prime EC tube morphogenic responses (i.e. added overnight prior to the morphogenic assay to hematopoietic stem cell cytokines in collagen matrices and, interestingly, they also prime EC tube morphogenesis in 3D fibrin matrices. EC-pericyte interactions in 3D fibrin matrices leads to marked vascular basement membrane assembly as demonstrated using immunofluorescence and transmission electron microscopy. Furthermore, we show that hematopoietic stem cell cytokines and pericytes stimulate EC sprouting in fibrin matrices in a manner dependent on the α5β1 integrin. This novel co-culture system, under serum-free defined conditions, allows for a molecular analysis of EC tube assembly, pericyte recruitment and maturation events in a critical ECM environment (i.e. fibrin matrices that regulates angiogenic events in postnatal life.

Enhanced CO{sub 2} capture on graphene via N, S dual-doping

Energy Technology Data Exchange (ETDEWEB)

Li, Jieyuan; Hou, Meiling [College of Architecture and Environment, Sichuan University (China); Chen, Yanqiu [Institute of New Energy and Low Carbon Technology, Sichuan University (China); Cen, Wanglai [Institute of New Energy and Low Carbon Technology, Sichuan University (China); National Engineering Research Center for Flue Gas Desulfurization (China); Chu, Yinghao, E-mail: chuyinghao@scu.edu.cn [College of Architecture and Environment, Sichuan University (China); National Engineering Research Center for Flue Gas Desulfurization (China); Yin, Shi, E-mail: yinshi_scu@foxmail.com [College of Architecture and Environment, Sichuan University (China)

2017-03-31

Highlights: • Sluggish conjugated π bonds of graphene should be weakened to promote adsorption activity. • A charge delivery channel along S → N → CO{sub 2} path should be prior responsible for the enhancement of CO{sub 2} capture on graphene. • Applicative temperature range of graphene-based adsorbents for CO{sub 2} capture is extend to about 100 °C via N, S dual-doping. - Abstract: N, S doped graphene-based materials have been recently recognized as promising adsorbents for CO{sub 2} capture, but understanding of the adsorption mechanism at the atomic level is still limited. Herein, the local structures and promotion mechanism of CO{sub 2} capture by N, S doped graphene were investigated by combining density functional theory and ab initio thermodynamics. A single vacancy defected graphene involving N, S dual-doping was found to be a superior adsorbent for CO{sub 2} capture under mild conditions (<100 °C, 1 atm). The enhanced CO{sub 2} adsorption performance should be ascribed to a charge delivery channel along the S → N → CO{sub 2} path, leading to extra charge transfer from graphene to CO{sub 2}. It is worth mentioning that the extra charge transfer was stimulated by the unique sp{sup 2} hybridization of pyridine N and further enhanced by S in N, S dual-doped graphene. A possible mechanism has been proposed to explain the high adsorption performance of CO{sub 2} by N, S dual-doped graphene, which offers insights for the design of new graphene-based adsorbents.

Influences of soil volume and an elevated CO[sub 2] level on growth and CO[sub 2] exchange for the crassulacean acid metabolism plant Opuntia ficus-indica

Energy Technology Data Exchange (ETDEWEB)

Nobel, P.S.; Cui, M.; Miller, P.M.; Luo, Y. (UCLA-DOE Lab., Univ. of California, Los Angeles, CA (United States))

1994-01-01

Effects of the current (38 Pa) and an elevated (74 Pa) CO[sub 2] partial pressure on root and shoot areas, biomass accumulation and daily net CO[sub 2] exchange were determined for opuntia ficus-indica (L.) Miller, a highly productive Crassulacean acid metabolism species cultivated worldwide. Plants were grown in environmentally controlled rooms for 18 weeks in pots of three soil volumes (2600, 6500 and 26000 cm[sup 3]), the smallest of which was intended to restrict root growth. For plants in the medium-sized soil volume, basal cladodes tended to be thicker and areas of main and lateral roots tended to be greater as the CO[sub 2] level was doubled. Daughter cladodes tended to be initiated sooner at the current compared with the elevated CO[sub 2] level but total areas were similar by 10 weeks. At 10 weeks, daily net CO[sub 2] uptake for the three soil volumes averaged 24% higher for plants growing under elevated compared with current CO-2 levels, but at 18 weeks only 3% enhancement in uptake occurred. Dry weight gain was enhanced 24% by elevated CO[sub 2] during the first 10 weeks but only 8% over 18 weeks. Increasing the soil volume 10-fold led to a greater stimulation of daily net CO[sub 2] uptake and biomass production than did doubling the CO[sub 2] level. At 18 weeks, root biomass doubled and shoot biomass nearly doubled as the soil volume was increased 10-fold; the effects of soil volume tended to be greater for elevated CO[sub 2]. The amount of cladode nitrogen per unit dry weight decreased as the CO[sub 2] level was raised and increased as soil volume increased, the latter suggesting that the effects of soil volume could be due to nitrogen limitations. (au) (30 refs.)

Optimized CO{sub 2} miscible hydrocarbon fracturing fluids

Energy Technology Data Exchange (ETDEWEB)

Taylor, R.S.; Funkhouser, G.P.; Fyten, G.; Attaway, D.; Watkins, H. [Halliburton Energy Services, Calgary, AB (Canada); Lestz, R.S. [Chevron Canada Resources, Calgary, AB (Canada); Loree, D. [FracEx Inc. (Canada)

2006-07-01

Carbon dioxide (CO{sub 2}) miscible hydrocarbon fracturing fluids address issues of fluid retention in low-permeability gas reservoirs, including undersaturated and underpressured reservoirs. An optimized surfactant gel technology using carbon dioxide (CO{sub 2}) hydrocarbon fracturing fluids applicable to all gas-well stimulation applications was discussed in this paper. The crosslinked surfactant gel technology improved proppant transport, leakoff control, and generation of effective fracture half-length. Tests indicated that application of the surfactant cooled the fracture face, which had the effect of extending break times and increasing viscosity during pumping periods. Rapid recovery of the fracturing fluid eliminated the need for swabbing in some cases, and the fluid system was not adversely affected by shear. However, rheological test equipment capable of mixing liquid CO{sub 2} and viscosified hydrocarbons at downhole temperatures is required to determine rheology and required chemical concentrations. It was recommended that to achieve an effective methane-drive cleanup mechanism, treatments should be designed so that the gellant system can be effective with up to 50 per cent CO{sub 2} dissolved in oil. It was concluded that it should be possible to apply the technology to low permeability gas reservoirs. Viscosity curves and friction data were presented. Issues concerning the selection of tubulars and flowback procedures were also discussed. It was suggested that the cost of the hydrocarbon fracturing fluid can be recovered by the sale of recovered load fluid. 6 refs., 4 figs.

A density functional theory study of the adsorption behaviour of CO{sub 2} on Cu{sub 2}O surfaces

Energy Technology Data Exchange (ETDEWEB)

Mishra, Abhishek Kumar, E-mail: akmishra@ddn.upes.ac.in, E-mail: abhishek.mishra@ucl.ac.uk, E-mail: deleeuwn@cardiff.ac.uk [Research & Development, University of Petroleum and Energy Studies (UPES), Bidholi, Dehradun 248007 (India); Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Roldan, Alberto [School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT (United Kingdom); Leeuw, Nora H. de, E-mail: akmishra@ddn.upes.ac.in, E-mail: abhishek.mishra@ucl.ac.uk, E-mail: deleeuwn@cardiff.ac.uk [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT (United Kingdom)

2016-07-28

Copper has many applications, particularly in electro-catalysis, where the oxidation state of the copper electrode plays a significant role in the selectivity towards products. Although copper-based materials have clear potential as catalysts in the reduction of CO{sub 2} and conversion to products, fundamental understanding of CO{sub 2} adsorption and activation on different copper oxide surfaces is still limited. We have used DFT+U methodology to study the surface reconstruction of the three most exposed (111), (110), and (001) surfaces of Cu{sub 2}O with different possible terminations. Considering several adsorbate geometries, we have investigated CO{sub 2} adsorption on five different possible terminations and proposed eight different configurations in which CO{sub 2} binds with the surface. Similar to earlier findings, CO{sub 2} binds weakly with the most stable Cu{sub 2}O(111):O surface showing no molecular activation, whereas a number of other surfaces, which can appear in the Cu{sub 2}O particles morphology, show stronger binding as well as activation of the CO{sub 2} molecule. Different CO{sub 2} coverages were studied and a detailed structural and electronic charge analysis is presented. The activation of the CO{sub 2} molecule is characterized by structural transformations and charge transfer between the surface and the CO{sub 2} molecule, which is further confirmed by considerable red shifts in the vibrational frequencies.

Single site porphyrine-like structures advantages over metals for selective electrochemical CO2 reduction

DEFF Research Database (Denmark)

Bagger, Alexander; Ju, Wen; Varela, Ana Sofia

2017-01-01

Currently, no catalysts are completely selective for the electrochemical CO2 Reduction Reaction (CO2RR). Based on trends in density functional theory calculations of reaction intermediates we find that the single metal site in a porphyrine-like structure has a simple advantage of limiting...... the competing Hydrogen Evolution Reaction (HER). The single metal site in a porphyrine-like structure requires an ontop site binding of hydrogen, compared to the hollow site binding of hydrogen on a metal catalyst surface. The difference in binding site structure gives a fundamental energy-shift in the scaling...... relation of ∼0.3eV between the COOH* vs. H* intermediate (CO2RR vs. HER). As a result, porphyrine-like catalysts have the advantage over metal catalyst of suppressing HER and enhancing CO2RR selectivity....

Role of CD28 co-stimulation in generation and maintenance of virus-specific T cells

DEFF Research Database (Denmark)

Christensen, Jeanette Erbo; Christensen, Jan P; Kristensen, Nanna N

2002-01-01

Efficient induction of T cell responses is normally assumed to require both TCR-mediated signaling and engagement of co-stimulatory molecules, in particular CD28. However, the importance of CD28 co-stimulation in induction and maintenance of antiviral T cell responses is not clearly established....... For this reason antiviral CD4(+) and CD8(+) T cell responses in CD28-deficient mice were studied using two different viruses [vesicular stomatitis virus and lymphocytic choriomeningitis virus (LCMV)]. Intracellular cytokine staining and/or MHC-peptide tetramers were used to enumerate antigen-specific T cells...

CO2-induced seawater acidification affects physiological performance of the marine diatom Phaeodactylum tricornutum

Directory of Open Access Journals (Sweden)

U. Riebesell

2010-09-01

Full Text Available CO2/pH perturbation experiments were carried out under two different pCO2 levels (39.3 and 101.3 Pa to evaluate effects of CO2-induced ocean acidification on the marine diatom Phaeodactylum tricornutum. After acclimation (>20 generations to ambient and elevated CO2 conditions (with corresponding pH values of 8.15 and 7.80, respectively, growth and photosynthetic carbon fixation rates of high CO2 grown cells were enhanced by 5% and 12%, respectively, and dark respiration stimulated by 34% compared to cells grown at ambient CO2. The half saturation constant (Km for carbon fixation (dissolved inorganic carbon, DIC increased by 20% under the low pH and high CO2 condition, reflecting a decreased affinity for HCO3– or/and CO2 and down-regulated carbon concentrating mechanism (CCM. In the high CO2 grown cells, the electron transport rate from photosystem II (PSII was photoinhibited to a greater extent at high levels of photosynthetically active radiation, while non-photochemical quenching was reduced compared to low CO2 grown cells. This was probably due to the down-regulation of CCM, which serves as a sink for excessive energy. The balance between these positive and negative effects on diatom productivity will be a key factor in determining the net effect of rising atmospheric CO2 on ocean primary production.

A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum

Directory of Open Access Journals (Sweden)

Laura Sordo

2016-09-01

Full Text Available Most ocean acidification (OA experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is controlled via direct analysis of pCO2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA that measures pCO2 and conveys this value to a Proportional-Integral-Derivative (PID controller. The controller commands a solenoid valve that opens and closes the CO2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of pCO2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum. We found that after 11 months of high CO2 exposure, photosynthesis increased with CO2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO2, such as temperature, irradiance and nutrients.

Hemiparasite abundance in an alpine treeline ecotone increases in response to atmospheric CO(2) enrichment.

Science.gov (United States)

Hättenschwiler, Stephan; Zumbrunn, Thomas

2006-02-01

Populations of the annual hemiparasites Melampyrum pratense L. and Melampyrum sylvaticum L. were studied at the treeline in the Swiss Alps after 3 years of in situ CO(2) enrichment. The total density of Melampyrum doubled to an average of 44 individuals per square meter at elevated CO(2) compared to ambient CO(2). In response to elevated CO(2), the height of the more abundant and more evenly distributed M. pratense increased by 20%, the number of seeds per fruit by 21%, and the total seed dry mass per fruit by 27%, but the individual seed size did not change. These results suggest that rising atmospheric CO(2) may stimulate the reproductive output and increase the abundance of Melampyrum in the alpine treeline ecotone. Because hemiparasites can have important effects on community dynamics and ecosystem processes, notably the N cycle, changing Melampyrum abundance may potentially influence the functioning of alpine ecosystems in a future CO(2)-rich atmosphere.

Assessment of soil nitrogen and phosphorous availability under elevated CO2 and N-fertilization in a short rotation poplar plantation

NARCIS (Netherlands)

Lagomarsino, A.; Moscatelli, M.C.; Hoosbeek, M.R.; Angelis, de P.; Grego, S.

2008-01-01

Photosynthetic stimulation by elevated [CO2] is largely regulated by nitrogen and phosphorus availability in the soil. During a 6 year Free Air CO2 Enrichment (FACE) experiment with poplar trees in two short rotations, inorganic forms of soil nitrogen, extractable phosphorus, microbial and total

The potential effects of concurrent increases in temperature, CO2 and O3 on net photosynthesis, as mediated by rubisCO

International Nuclear Information System (INIS)

Long, S.; Essex Univ., Colchester

1992-07-01

At the leaf level, under light saturating and light limiting conditions, it is shown that elevated atmospheric CO 2 concentration not only alters the scale of the response of carbon gain to rising temperature, but can alter the direction of response. These points bring into serious question the value of any predictions of plant production which ignore not only the direct effect Of C0 2 on carbon gain, but also the basic interactions of temperature, C0 2 and 0 3 . Whilst many factors may potentially diminish the enhancement of lightsaturated leaf photosynthetic rates with increase in atmospheric CO 2 concentrations, no mechanism has so far been identified which could remove the parallel stimulation of light-limited photosynthesis

Study of the Imidazolium-Based Ionic Liquid - ag Electrified Interface on the CO_{2} Electroreduction by Sum Frequency Spectroscopy.

Science.gov (United States)

Garcia Rey, Natalia; Dlott, Dana

2017-06-01

Imidazolium based ionic liquids (ILs) have been used as a promising system to improve the CO_{2} electroreduction at lower overpotential than other organic or aqueous electrolytes^{1}. Although the detailed mechanism of the CO_{2} electroreduction on Ag has not been elucidated yet, we have developed a methodology to study the electrified interface during the CO_{2} electroreduction using sum frequency generation (SFG) spectroscopy in combination with cyclic voltammetry^{2}. In this work, we tuned the composition of imidazolium-based ILs by exchanging the anion or the functional groups of the imidazolium. We use the nonresonant SFG (NR-SFG) to study the IL-Ag interface and resonant SFG (RES-SFG) to identify the CO adsorbed on the electrode and monitor the Stark shift as a function of cell potential. In previous studies on CO_{2} electroreduction in the IL: 1-ethyl-3-methylimidazolium tetrafluorborate (EMIM-BF_{4}) on Ag, we showed three events occurred at the same potential (-1.33 V vs. Ag/AgCl): the current associated with CO_{2} electroreduction increased, the Stark shift of the adsorbed atop CO doubled in magnitude and the EMIM-BF_{4} underwent a structural transition^{3}. In addition, we also observed how the structural transition of the EMIM-BF_{4} electrolyte shift to lower potentials when the IL is mixed with water. It is known that water enhances the CO_{2} electroreduction producing more CO^{4}. Moreover, the CO is adsorbed in multi-bonded and in atop sites when more water is present in the electrolyte. ^{1}Lau, G. P. S.; Schreier, M.; Vasilyev, D.; Scopelliti, R.; Grätzel, M.; Dyson, P. J., New Insights into the Role of Imidazolium-Based Promoters for the Electroreduction of CO_{2} on a Silver Electrode. J. Am. Chem. Soc. 2016, 138, 7820-7823. ^{2}Garcia Rey, N.; Dlott, D. D., Studies of Electrochemical Interfaces by Broadband Sum Frequency Generation. J. Electroanal. Chem. 2016. DOI:10.1016/j.jelechem.2016.12.023. ^{3}Garcia Rey, N.; Dlott, D. D

Co-cultivation of Streptomyces californicus and Stachybotrys chartarum stimulates the production of cytostatic compound(s) with immunotoxic properties

International Nuclear Information System (INIS)

Penttinen, Piia; Pelkonen, Jukka; Huttunen, Kati; Hirvonen, Maija-Riitta

2006-01-01

We have recently shown that the actinobacterium Streptomyces californicus and the fungus Stachybotrys chartarum originating from moisture damaged buildings possess both immunotoxic and immunostimulatory characteristics, which are synergistically potentiated by microbial interaction. In the search for the causative agent(s) behind the immunotoxicity, the cytostatic effects of the co-cultivated spores of S. californicus and S. chartarum were compared to those caused by widely used cytostatic agents produced by streptomycetes. The RAW264.7 macrophages were exposed to four doses of doxorubicin (DOX), actinomycin D (AMD), mitomycin C (MMC) or phleomycin (PHLEO) for 24 h. Kinetics of the spores of the co-cultivated and the separately cultivated microbes (1 x 10 6 spores/ml) was compared to DOX (0.15 μM). Apoptotic responses were analyzed by measuring DNA content and mitochondria membrane depolarization with flow cytometer, and by the fluorometric caspase-3 assay. The present data indicate that interactions during co-cultivation of S. californicus and S. chartarum stimulate the production of an unidentified cytostatic compound(s) capable of inducing mitochondria mediated apoptosis and cell cycle arrest at S-G 2 /M. The spores of co-cultivated microbes caused a 4-fold collapse of mitochondrial membrane potential and an almost 6-fold caspase-3 activation and DNA fragmentation when compared to control. Similar responses were induced by DNA cleaving compounds, especially DOX and AMD, at the relatively low concentrations, but not the spores of the same microbes when they were grown separately. These data suggest that when growing in the same habitat, interactions between S. californicus and S. chartarum stimulates the production of an unknown cytostatic compound(s) which evoke immunotoxic effects similar to those by chemotherapeutic drugs

CO2-handling: Incomes and risks. Can it be done with profitability?

International Nuclear Information System (INIS)

Lunke, Birger

2006-01-01

Focus on profitability in CO 2 handling can make it commercially interesting and stimulate technological innovation in the area. EOR (Enhanced Oil Recovery) is central to the profitability of carbon capture. Various political and economical aspects are discussed, underlining the need for big investments and a predictable tax regime for the industry to develop

Trends in global CO2 emissions. 2013 Report

Energy Technology Data Exchange (ETDEWEB)

Olivier, J.G.J.; Peters, J.A.H.W. [PBL Netherlands Environmental Assessment Agency, Den Haag (Netherlands); Janssens-Maenhout, G. [Institute for Environment and Sustainability IES, European Commission' s Joint Research Centre JRC, Ispra (Italy); Muntean, M. [Institute for Environment and Sustainability IES, Joint Research Centre JRC, Ispra (Italy)

2013-10-15

greenhouse gas emissions. Chapter 3 focuses on the energy trends and possible fuel shifts, as the special topic for this year's report. Compared to last year's report, global energy trends are described more fully, including an analysis of the main options for reducing emissions, being renewable energy, nuclear power, energy efficiency and carbon capture and storage. In addition, the extent to which structural changes have caused the observed slowdown in the increase in global CO2 emissions is discussed. Finally, Chapter 4 summarises the main conclusions on trends, mitigation achievements and prospects.

Transport sector CO2 emissions growth in Asia: Underlying factors and policy options

International Nuclear Information System (INIS)

Timilsina, Govinda R.; Shrestha, Ashish

2009-01-01

This study analyze the potential factors influencing the growth of transport sector carbon dioxide (CO 2 ) emissions in selected Asian countries during the 1980-2005 period by decomposing annual emissions growth into components representing changes in fuel mix, modal shift, per capita gross domestic product (GDP) and population, as well as changes in emission coefficients and transportation energy intensity. We find that changes in per capita GDP, population growth and transportation energy intensity are the main factors driving transport sector CO 2 emission growth in the countries considered. While growth in per capita income and population are responsible for the increasing trend of transport sector CO 2 emissions in China, India, Indonesia, Republic of Korea, Malaysia, Pakistan, Sri Lanka and Thailand; the decline of transportation energy intensity is driving CO 2 emissions down in Mongolia. Per capita GDP, population and transportation energy intensity effects are all found responsible for transport sector CO 2 emissions growth in Bangladesh, the Philippines and Vietnam. The study also reviews existing government policies to limit CO 2 emissions growth, such as fiscal instruments, fuel economy standards and policies to encourage switching to less emission intensive fuels and transportation modes.

Impact of H2/CO ratios on phase and performance of Mn-modified Fe-based Fischer Tropsch synthesis catalyst

International Nuclear Information System (INIS)

Ding, Mingyue; Yang, Yong; Li, Yongwang; Wang, Tiejun; Ma, Longlong; Wu, Chuangzhi

2013-01-01

Highlights: ► Decreasing H 2 /CO ratio facilitated the conversion of Fe 3 O 4 to iron carbides on the surface layers. ► The formation of surface carbonaceous species was promoted in higher CO partial pressure. ► The formation of iron carbides on the surface of Fe 3 O 4 provided the FTS active sites. ► Decreasing H 2 /CO ratio promoted the product shifting towards heavy hydrocarbons. - Abstract: Impacts of H 2 /CO ratios on both the bulky and surface compositions of an iron–manganese based catalyst were investigated by XRD, MES, N 2 -physisorption, XPS and LRS. Fischer–Tropsch (F–T) synthesis performances were studied in a slurry-phase continuously stirred tank reactor. The characterization results showed that the fresh catalyst was comprised of the hematite, which was converted firstly to Fe 3 O 4 , and then carburized to iron carbides in both the bulk and surface regions under different H 2 /CO ratios atmosphere. Pretreatment in lower H 2 /CO ratio facilitated the formation of iron carbides on the surface of magnetite and surface carbonaceous species. During the F–T synthesis reaction, the catalyst reduced in lower H 2 /CO ratio presented higher catalytic activity, which is assigned probably to the formation of more iron carbides (especially for χ-Fe 5 C 2 ) on the surface of magnetite. The increase of CO partial pressure promoted the product distribution shifting towards heavy hydrocarbons

Seasonal variation of air-sea CO2 fluxes in the Terra Nova Bay of the Ross Sea, Antarctica, based on year-round pCO2 observations

Science.gov (United States)

Zappa, C. J.; Rhee, T. S.; Kwon, Y. S.; Choi, T.; Yang, E. J.; Kim, J.

2017-12-01

The polar oceans are rapidly changing in response to climate variability. In particular, augmented inflow of glacial melt water and shrinking sea-ice extent impacts the polar coastal oceans, which may in turn shift the biogeochemistry into an unprecedented paradigm not experienced previously. Nonetheless, most research in the polar oceans is limited to the summer season. Here, we present the first direct observations of ocean and atmospheric pCO2 measured near the coast of Terra Nova Bay in the Ross Sea, Antarctica, ongoing since February, 2015 at Jang Bogo Station. The coastal area is covered by landfast sea-ice from spring to fall while continually exposed to the atmosphere during summer season only. The pCO2 in seawater swung from 120 matm in February to 425 matm in early October. Although sea-ice still covers the coastal area, pCO2 already started decreasing after reaching the peak in October. In November, the pCO2 suddenly dropped as much as 100 matm in a week. This decrease of pCO2 continued until late February when the sea-ice concentration was minimal. With growing sea ice, the pCO2 increased logarithmically reaching the atmospheric concentration in June/July, depending on the year, and continued to increase until October. Daily mean air-sea CO2 flux in the coastal area widely varied from -70 mmol m-2 d-1 to 20 mmol m-2 d-1. Based on these observations of pCO2 in Terra Nova Bay, the annual uptake of CO2 is 8 g C m-2, estimated using the fraction of sea-ice concentration estimated from AMSR2 microwave emission imagery. Extrapolating to all polynyas surrounding Antarctica, we expect the annual uptake of 8 Tg C in the atmosphere. This is comparable to the amount of CO2 degassed into the atmosphere south of the Antarctic Polar Front (62°S).

Effects of Biochar Addition on CO2 and N2O Emissions following Fertilizer Application to a Cultivated Grassland Soil.

Science.gov (United States)

Chen, Jingjing; Kim, Hyunjin; Yoo, Gayoung

2015-01-01

Carbon (C) sequestration potential of biochar should be considered together with emission of greenhouse gases when applied to soils. In this study, we investigated CO2 and N2O emissions following the application of rice husk biochars to cultivated grassland soils and related gas emissions tos oil C and nitrogen (N) dynamics. Treatments included biochar addition (CHAR, NO CHAR) and amendment (COMPOST, UREA, NO FERT). The biochar application rate was 0.3% by weight. The temporal pattern of CO2 emissions differed according to biochar addition and amendments. CO2 emissions from the COMPOST soils were significantly higher than those from the UREA and NO FERT soils and less CO2 emission was observed when biochar and compost were applied together during the summer. Overall N2O emission was significantly influenced by the interaction between biochar and amendments. In UREA soil, biochar addition increased N2O emission by 49% compared to the control, while in the COMPOST and NO FERT soils, biochar did not have an effect on N2O emission. Two possible mechanisms were proposed to explain the higher N2O emissions upon biochar addition to UREA soil than other soils. Labile C in the biochar may have stimulated microbial N mineralization in the C-limited soil used in our study, resulting in an increase in N2O emission. Biochar may also have provided the soil with the ability to retain mineral N, leading to increased N2O emission. The overall results imply that biochar addition can increase C sequestration when applied together with compost, and might stimulate N2O emission when applied to soil amended with urea.

CO2-Induced Changes in Wheat Grain Composition: Meta-Analysis and Response Functions

Directory of Open Access Journals (Sweden)

Malin C. Broberg

2017-04-01

Full Text Available Elevated carbon dioxide (eCO2 stimulates wheat grain yield, but simultaneously reduces protein/nitrogen (N concentration. Also, other essential nutrients are subject to change. This study is a synthesis of wheat experiments with eCO2, estimating the effects on N, minerals (B, Ca, Cd, Fe, K, Mg, Mn, Na, P, S, Zn, and starch. The analysis was performed by (i deriving response functions to assess the gradual change in element concentration with increasing CO2 concentration, (ii meta-analysis to test the average magnitude and significance of observed effects, and (iii relating CO2 effects on minerals to effects on N and grain yield. Responses ranged from zero to strong negative effects of eCO2 on mineral concentration, with the largest reductions for the nutritionally important elements of N, Fe, S, Zn, and Mg. Together with the positive but small and non-significant effect on starch concentration, the large variation in effects suggests that CO2-induced responses cannot be explained only by a simple dilution model. To explain the observed pattern, uptake and transport mechanisms may have to be considered, along with the link of different elements to N uptake. Our study shows that eCO2 has a significant effect on wheat grain stoichiometry, with implications for human nutrition in a world of rising CO2.