Salt budget for West Pond, Utah, April 1987 to June 1989

USGS Publications Warehouse

Wold, S.R.; Waddell, K.M.

1994-01-01

During operation of the West Desert pumping project, April 10. 1987, to June 30, 1989, data were collected as part of a monitoring program to evaluate the effects of pumping brine from Great Salt Lake into West Pond in northern Utah. The removal of brine from Great Sail was part of an effort to lower the level of Great Salt Lake when the water level was at a high in 1986. These data were used to prepare a salt budget that indicates about 695 million tons of salt or about 14.2 percent of salt contained in Great Salt Lake was pumped into West Pond. Of the 695 million tons of salt pumped into West Pond, 315 million tons (45 percent) were dissolved in West Pond, 71 million tons (10.2 percent) formed a salt crust at the bottom of the pond, 10 million tons (1.4 percent) infiltrated the subsurface areas inundated by storage in the pond, 88 million tons (12.7 percent) were withdrawn by American Magnesium Corporation, and 123 million tons (17.7 percent) discharged from the pond through the Newfoundland weir. About 88 million tons (13 percent) of the salt pumped from the lake could not be accounted for in the salt budget. About 94 million tons of salt (1.9 percent of the total salt in Great Salt Lake) flowed back to Great Salt Lake.

Use and engineering of efflux pumps for the export of olefins in microbes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukhopadhyay, Aindrila

2016-07-14

The scope of the project is to investigate efflux pump systems in engineered host microorganisms, such as E. coli, and develop a pump engineered to export a target compound. To initiate the project in coordination with other TOTAL driven projects, the first target compound to be studied was 1-hexene. However, we were investigating other chemicals as Styrene. The main goal of the project was to generate a set of optimized efflux pump systems for microorganisms (E. coli and Streptomyces or other host) engineered to contain biosynthetic pathways to export large titers of target compounds that are toxic (or accumulate andmore » push back biosynthesis) to the host cell. An optimized microbial host will utilize specific and efficient cell wall located pumps to extrude harmful target compounds and enable greater production of these compounds.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robb, Kevin R.; Jain, Prashant K.; Hazelwood, Thomas J.

Fluoride salt cooled high-temperature reactor (FHR) concepts include pumps for forced circulation of the primary and secondary coolants. As part of a cooperative research and development agreement between the Shanghai Institute of Applied Physics and the Oak Ridge National Laboratory (ORNL), a research project was initiated to aid in the development of pumps for high-temperature salts. The objectives of the task included characterization of the behavior of an existing ORNL LSTL pump; design and test a modified impeller and volute for improved pump characteristics; and finally, provide lessons learned, recommendations, and guidelines for salt pump development and design. The pumpmore » included on the liquid salt test loop (LSTL) at ORNL served as a case study. This report summarizes the progress to date. The report is organized as follows. First, there is a review, focused on pumps, of the significant amount of work on salts at ORNL during the 1950s 1970s. The existing pump on the LSTL is then described. Plans for hot and cold testing of the pump are then discussed, including the design for a cold shakedown test stand and the required LSTL modifications for hot testing. Initial hydraulic and vibration modeling of the LSTL pump is documented. Later, test data from the LSTL will be used to validate the modeling approaches, which could then be used for future pump design efforts. Some initial insights and test data from the pump are then provided. Finally, some preliminary design goals and requirements for a future LSTL pump are provided as examples of salt pump design considerations.« less

Tocopherol deficiency reduces sucrose export from salt-stressed potato leaves independently of oxidative stress and symplastic obstruction by callose

PubMed Central

Asensi-Fabado, María Amparo; Ammon, Alexandra; Sonnewald, Uwe; Munné-Bosch, Sergi; Voll, Lars M.

2015-01-01

Tocopherol cyclase, encoded by the gene SUCROSE EXPORT DEFECTIVE1, catalyses the second step in the synthesis of the antioxidant tocopherol. Depletion of SXD1 activity in maize and potato leaves leads to tocopherol deficiency and a ‘sugar export block’ phenotype that comprises massive starch accumulation and obstruction of plasmodesmata in paraveinal tissue by callose. We grew two transgenic StSXD1:RNAi potato lines with severe tocopherol deficiency under moderate light conditions and subjected them to salt stress. After three weeks of salt exposure, we observed a strongly reduced sugar exudation rate and a lack of starch mobilization in leaves of salt-stressed transgenic plants, but not in wild-type plants. However, callose accumulation in the vasculature declined upon salt stress in all genotypes, indicating that callose plugging of plasmodesmata was not the sole cause of the sugar export block phenotype in tocopherol-deficient leaves. Based on comprehensive gene expression analyses, we propose that enhanced responsiveness of SnRK1 target genes in mesophyll cells and altered redox regulation of phloem loading by SUT1 contribute to the attenuation of sucrose export from salt-stressed SXD:RNAi source leaves. Furthermore, we could not find any indication that elevated oxidative stress may have served as a trigger for the salt-induced carbohydrate phenotype of SXD1:RNAi transgenic plants. In leaves of the SXD1:RNAi plants, sodium accumulation was diminished, while proline accumulation and pools of soluble antioxidants were increased. As supported by phytohormone contents, these differences seem to increase longevity and prevent senescence of SXD:RNAi leaves under salt stress. PMID:25428995

Short- and medium-chain fatty acids enhance the cell surface expression and transport capacity of the bile salt export pump (BSEP/ABCB11).

PubMed

Kato, Takuya; Hayashi, Hisamitsu; Sugiyama, Yuichi

2010-09-01

The reduced expression of the bile salt export pump (BSEP/ABCB11) at the canalicular membrane is associated with cholestasis-induced hepatotoxicity due to the accumulation of bile acids in hepatocytes. We previously reported that 4-phenylbutyrate (4PBA), an approved drug for urea cycle disorders, is a promising agent for intrahepatic cholestasis because it increases both the cell surface expression and the transport capacity of BSEP. In the present study, we searched for effective compounds other than 4PBA by focusing on short- and medium-chain fatty acids, which have similar characteristics to 4PBA such as their low-molecular-weight and a carboxyl group. In transcellular transport studies using Madin-Darby canine kidney (MDCK) II cells, all short- and medium-chain fatty acids tested except for formate, acetate, and hexanoic acid showed more potent effects on wild type (WT) BSEP-mediated [3H]taurocholate transport than did 4PBA. The increase in WT BSEP transport with butyrate and octanoic acid treatment correlated with an increase in its expression at the cell surface. Two PFIC2-type variants, E297G and D482G BSEP, were similarly affected with both compounds treatment. The prolonged half-life of cell surface-resident WT BSEP was responsible for this increased octanoic acid-stimulated transport, but not for that of butyrate. In conclusion, short- and medium-chain fatty acids have potent effects on the increase in WT and PFIC2-type BSEP-mediated transport in MDCK II cells. Although both short- and medium-chain fatty acids enhance the transport capacity of WT and PFIC2-type BSEP by inducing those expressions at the cell surface, the underlying mechanism seems to differ between fatty acids. 2010 Elsevier B.V. All rights reserved.

4-phenylbutyrate enhances the cell surface expression and the transport capacity of wild-type and mutated bile salt export pumps.

PubMed

Hayashi, Hisamitsu; Sugiyama, Yuichi

2007-06-01

Progressive familial intrahepatic cholestasis type 2 (PFIC2) is caused by a mutation in the bile salt export pump (BSEP/ABCB11) gene. We previously reported that E297G and D482G BSEP, which are frequently found mutations in European patients, result in impaired membrane trafficking, whereas both mutants retain their transport function. The dysfunctional localization is probably attributable to the retention of BSEP in endoplasmic reticulum (ER) followed by proteasomal degradation. Because sodium 4-phenylbutyrate (4PBA) has been shown to restore the reduced cell surface expression of mutated plasma membrane proteins, in the current study, we investigated the effect of 4PBA treatment on E297G and D482G BSEP. Transcellular transport and cell surface biotinylation studies using Madin-Darby canine kidney (MDCK) II cells demonstrated that 4PBA treatment increased functional cell surface expression of wild-type (WT), E297G, and D482G BSEP. The prolonged half-life of cell surface-resident BSEP with 4PBA treatment was responsible for this result. Moreover, treatment of Sprague-Dawley rats with 4PBA resulted in an increase in BSEP expression at the canalicular membrane, which was accompanied by an increase in the biliary excretion of [(3)H]taurocholic acid (TC). 4PBA treatment with a clinically achievable concentration enhances the cell surface expression and the transport capacity of WT, E297G, and D482G BSEP in MDCK II cells, and also induces functional BSEP expression at the canalicular membrane and bile acid transport via canalicular membrane in vivo. 4PBA is a potential pharmacological agent for treating not only PFIC2 patients with E297G and D482G mutations but also other cholestatic patients, in whom the BSEP expression at the canalicular membrane is reduced.

Short-chain ubiquitination is associated with the degradation rate of a cell-surface-resident bile salt export pump (BSEP/ABCB11).

PubMed

Hayashi, Hisamitsu; Sugiyama, Yuichi

2009-01-01

The reduced expression of the bile salt export pump (BSEP/ABCB11) at the canalicular membrane is associated with cholestasis-induced hepatotoxicity due to the accumulation of bile acids in hepatocytes. We demonstrated previously that 4-phenylbutyrate (4PBA) treatment, a U.S. Food and Drug Administration-approved drug for the treatment of urea cycle disorders, induces the cell-surface expression of BSEP by prolonging the degradation rate of cell-surface-resident BSEP. On the other hand, BSEP mutations, E297G and D482G, found in progressive familial intrahepatic cholestasis type 2 (PFIC2), reduced it by shortening the degradation rate of cell-surface-resident BSEP. Therefore, to help the development of the medical treatment of cholestasis, we investigated the underlying mechanism by which 4PBA and PFIC2-type mutations affect the BSEP degradation from cell surface, focusing on short-chain ubiquitination. In Madin-Darby canine kidney II (MDCK II) cells expressing BSEP and rat canalicular membrane vesicles, the molecular mass of the mature form of BSEP/Bsep shifted from 170 to 190 kDa after ubiquitin modification (molecular mass, 8 kDa). Ubiquitination susceptibility of BSEP/Bsep was reduced in vitro and in vivo by 4PBA treatment and, conversely, was enhanced by BSEP mutations E297G and D482G. Moreover, biotin-labeling studies using MDCK II cells demonstrated that the degradation of cell-surface-resident chimeric protein fusing ubiquitin to BSEP was faster than that of BSEP itself. In conclusion, BSEP/Bsep is modified with two to three ubiquitins, and its ubiquitination is modulated by 4PBA treatment and PFIC2-type mutations. Modulation of short-chain ubiquitination can regulate the change in the degradation rate of cell-surface-resident BSEP by 4PBA treatment and PFIC2-type mutations.

TYPES OF SALT MARSH EDGE AND EXPORT OF TROPHIC ENERGY FROM MARSHES TO DEEPER HABITATS

EPA Science Inventory

We quantified nekton and estimated trophic export at salt marshes with both erosional and depositional edges at the Goodwin Islands (York River, Virginia, USA). At depositional-edge marshes, we examined trophic flows through quantitative sampling with 1.75 m2 drop rings, and thro...

Glass-wool study of laser-induced spin currents en route to hyperpolarized Cs salt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishikawa, Kiyoshi

2011-07-15

The nuclear spin polarization of optically pumped Cs atoms flows to the surface of Cs hydride in a vapor cell. A fine glass wool lightly coated with the salt helps greatly increase the surface area in contact with the pumped atoms and enhance the spin polarization of the salt nuclei. Even though the glass wool randomly scatters the pump light, the atomic vapor can be polarized with unpolarized light in a magnetic field. The measured enhancement in the salt enables study of the polarizations of light and atomic nuclei very near the salt surface.

Mesoscale eddies drive increased silica export in the subtropical Pacific Ocean.

PubMed

Benitez-Nelson, Claudia R; Bidigare, Robert R; Dickey, Tommy D; Landry, Michael R; Leonard, Carrie L; Brown, Susan L; Nencioli, Francesco; Rii, Yoshimi M; Maiti, Kanchan; Becker, Jamie W; Bibby, Thomas S; Black, Wil; Cai, Wei-Jun; Carlson, Craig A; Chen, Feizhou; Kuwahara, Victor S; Mahaffey, Claire; McAndrew, Patricia M; Quay, Paul D; Rappé, Michael S; Selph, Karen E; Simmons, Melinda P; Yang, Eun Jin

2007-05-18

Mesoscale eddies may play a critical role in ocean biogeochemistry by increasing nutrient supply, primary production, and efficiency of the biological pump, that is, the ratio of carbon export to primary production in otherwise nutrient-deficient waters. We examined a diatom bloom within a cold-core cyclonic eddy off Hawaii. Eddy primary production, community biomass, and size composition were markedly enhanced but had little effect on the carbon export ratio. Instead, the system functioned as a selective silica pump. Strong trophic coupling and inefficient organic export may be general characteristics of community perturbation responses in the warm waters of the Pacific Ocean.

Vectorial transport of unconjugated and conjugated bile salts by monolayers of LLC-PK1 cells doubly transfected with human NTCP and BSEP or with rat Ntcp and Bsep.

PubMed

Mita, Sachiko; Suzuki, Hiroshi; Akita, Hidetaka; Hayashi, Hisamitsu; Onuki, Reiko; Hofmann, Alan F; Sugiyama, Yuichi

2006-03-01

Na(+)-taurocholate-cotransporting peptide (NTCP)/SLC10A1 and bile salt export pump (BSEP)/ABCB11 synergistically play an important role in the transport of bile salts by the hepatocyte. In this study, we transfected human NTCP and BSEP or rat Ntcp and Bsep into LLC-PK1 cells, a cell line devoid of bile salts transporters. Transport by these cells was characterized with a focus on substrate specificity between rats and humans. The basal to apical flux of taurocholate across NTCP- and BSEP-expressing LLC-PK1 monolayers was 10 times higher than that in the opposite direction, whereas the flux across the monolayer of control and NTCP or BSEP single-expressing cells did not show any vectorial transport. The basal to apical flux of taurocholate was saturated with a K(m) value of 20 microM. Vectorial transcellular transport was also observed for cholate, chenodeoxycholate, ursodeoxycholate, their taurine and glycine conjugates, and taurodeoxycholate and glycodeoxycholate, whereas no transport of lithocholate was detected. To evaluate the respective functions of NTCP and BSEP and to compare them with those of rat Ntcp and Bsep, we calculated the clearance by each transporter in this system. A good correlation in the clearance of the examined bile salts (cholate, chenodeoxycholate, ursodeoxycholate, and their taurine or glycine conjugates) was observed between transport by human and that of rat transporters in terms of their rank order: for NTCP, taurine conjugates > glycine conjugates > unconjugated bile salts, and for BSEP, unconjugated bile salts and glycine conjugates > taurine conjugates. In conclusion, the substrate specificity of human and rat NTCP and BSEP appear to be very similar at least for monovalent bile salts under physiological conditions.

Plankton networks driving carbon export in the oligotrophic ocean

PubMed Central

Larhlimi, Abdelhalim; Roux, Simon; Darzi, Youssef; Audic, Stephane; Berline, Léo; Brum, Jennifer; Coelho, Luis Pedro; Espinoza, Julio Cesar Ignacio; Malviya, Shruti; Sunagawa, Shinichi; Dimier, Céline; Kandels-Lewis, Stefanie; Picheral, Marc; Poulain, Julie; Searson, Sarah; Stemmann, Lars; Not, Fabrice; Hingamp, Pascal; Speich, Sabrina; Follows, Mick; Karp-Boss, Lee; Boss, Emmanuel; Ogata, Hiroyuki; Pesant, Stephane; Weissenbach, Jean; Wincker, Patrick; Acinas, Silvia G.; Bork, Peer; de Vargas, Colomban; Iudicone, Daniele; Sullivan, Matthew B.; Raes, Jeroen; Karsenti, Eric; Bowler, Chris; Gorsky, Gabriel

2015-01-01

The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterised. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria, alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of just a few bacterial and viral genes can predict most of the variability in carbon export in these regions. PMID:26863193

Plankton networks driving carbon export in the oligotrophic ocean

NASA Astrophysics Data System (ADS)

2016-04-01

The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis, exported through sinking particles, and finally sequestered in the deep ocean. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure driving the process remains largely uncharacterized. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of carbon export in the oligotrophic ocean. We show that specific plankton communities, from the surface and deep chlorophyll maximum, correlate with carbon export at 150 m and highlight unexpected taxa such as Radiolaria and alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical, nutrient-depleted, oligotrophic ocean. Additionally, we show that the relative abundance of a few bacterial and viral genes can predict a significant fraction of the variability in carbon export in these regions.

Development of high temperature transport technology for LiCl-KCl eutectic salt in pyroprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sung Ho; Lee, Hansoo; Kim, In Tae

The development of high-temperature transport technologies for molten salt is a prerequisite and a key issue in the industrialization of pyro-reprocessing for advanced fuel cycle scenarios. The solution of a molten salt centrifugal pump was discarded because of the high corrosion power of a high temperature molten salt, so the suction pump solution was selected. An apparatus for salt transport experiments by suction was designed and tested using LiC-KCl eutectic salt. The experimental results of lab-scale molten salt transport by suction showed a 99.5% transport rate (ratio of transported salt to total salt) under a vacuum range of 100 mtorrmore » - 10 torr at 500 Celsius degrees. The suction system has been integrated to the PRIDE (pyroprocessing integrated inactive demonstration) facility that is a demonstrator using non-irradiated materials (natural uranium and surrogate materials). The performance of the suction pump for the transport of molten salts has been confirmed.« less

Spin-injection optical pumping of molten cesium salt and its NMR diagnosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishikawa, Kiyoshi

2015-07-15

Nuclear spin polarization of cesium ions in the salt was enhanced during optical pumping of cesium vapor at high magnetic field. Significant motional narrowing and frequency shift of NMR signals were observed by intense laser heating of the salt. When the hyperpolarized salt was cooled by blocking the heating laser, the signal width and frequency changed during cooling and presented the phase transition from liquid to solid. Hence, we find that the signal enhancement is mostly due to the molten salt and nuclear spin polarization is injected into the salt efficiently in the liquid phase. We also show that opticalmore » pumping similarly induces line narrowing in the solid phase. The use of powdered salt provided an increase in effective surface area and signal amplitude without glass wool in the glass cells.« less

High V-PPase activity is beneficial under high salt loads, but detrimental without salinity.

PubMed

Graus, Dorothea; Konrad, Kai R; Bemm, Felix; Patir Nebioglu, Meliha Görkem; Lorey, Christian; Duscha, Kerstin; Güthoff, Tilman; Herrmann, Johannes; Ferjani, Ali; Cuin, Tracey Ann; Roelfsema, M Rob G; Schumacher, Karin; Neuhaus, H Ekkehard; Marten, Irene; Hedrich, Rainer

2018-06-25

The membrane-bound proton-pumping pyrophosphatase (V-PPase), together with the V-type H + -ATPase, generates the proton motive force that drives vacuolar membrane solute transport. Transgenic plants constitutively overexpressing V-PPases were shown to have improved salinity tolerance, but the relative impact of increasing PP i hydrolysis and proton-pumping functions has yet to be dissected. For a better understanding of the molecular processes underlying V-PPase-dependent salt tolerance, we transiently overexpressed the pyrophosphate-driven proton pump (NbVHP) in Nicotiana benthamiana leaves and studied its functional properties in relation to salt treatment by primarily using patch-clamp, impalement electrodes and pH imaging. NbVHP overexpression led to higher vacuolar proton currents and vacuolar acidification. After 3 d in salt-untreated conditions, V-PPase-overexpressing leaves showed a drop in photosynthetic capacity, plasma membrane depolarization and eventual leaf necrosis. Salt, however, rescued NbVHP-hyperactive cells from cell death. Furthermore, a salt-induced rise in V-PPase but not of V-ATPase pump currents was detected in nontransformed plants. The results indicate that under normal growth conditions, plants need to regulate the V-PPase pump activity to avoid hyperactivity and its negative feedback on cell viability. Nonetheless, V-PPase proton pump function becomes increasingly important under salt stress for generating the pH gradient necessary for vacuolar proton-coupled Na + sequestration. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Effects of the West Desert Pumping Project on Near-Surface Brine Resources in the Newfoundland Basin, Tooele and Box Elder Counties, Utah

NASA Astrophysics Data System (ADS)

White, W. W.; Jones, B. F.; Kohler, J. F.

2006-12-01

The Bureau of Land Management and U.S. Geological Survey have identified changes in Newfoundland Basin shallow-brine aquifer chemistry that resulted from pumping Great Salt Lake brine into the Newfoundland Evaporation Basin during the West Desert pumping project. The pumping project was operated by the State of Utah from April 1987, to June 1989 in an attempt to lower the historically high level of Great Salt Lake (pond elevation was 4,211.85 feet in 1986). Effects of the pumping on the Newfoundland Basin included altering the chemical character of the shallow brine aquifer by mixing two chemically different brines, and depositing a halite salt crust where none was previously reported on the lacustrine sediments of the Newfoundland Basin playa. The halite salt crust resulted from evaporation of the brine pond generated by the pumping project. Changes in the shallow-brine aquifer chemistry were determined by comparing pre-pumping brine chemistry with that of post pumping brine, and examining variation with borehole depth and location (i.e., playa periphery vs central basin topographic low) of specific analyte concentration profiles and solid-phase mineral assemblages obtained from analyses of core sample pore water and mineralogy. Brine sample analyses from 72 exploratory boreholes drilled in the Newfoundland Basin by Reynolds Metals Company during the mid 1960's provided pre-pumping brine chemistry. Post pumping chemistry was obtained from analyses of brine samples from 24 boreholes hand-augured between 1998 and 2001 in the central and peripheral portions of the Newfoundland Basin. TEQUIL, a brine equilibrium model, was used to better understand how the Great Salt Lake brines introduced into the Newfoundland Basin may have interacted with fluids contained within the Basin's shallow-brine aquifer. TEQUIL identified the sequence of mineral precipitation from evaporation of pre and post-pumping Newfoundland Basin shallow-aquifer fluids and Great Salt Lake brine. The model was also used to simulate 50-50 mixing of Great Salt Lake brine with pre-pumping Newfoundland Basin shallow-aquifer. The resulting precipitated mineral suite from sequential evaporation of the simulated brine mix was nearly identical to that from TEQUIL simulation of the post-pumping Newfoundland Basin brine. This differed from the mineral suite precipitated from the pre-pumping Newfoundland Basin brine. Examination of pore water chemistry and solid-phase mineralogy from borehole core samples taken from the playa periphery to the basin topographic low illustrate the following chemical and mineralogical generalities. At peripheral sites, magnesium and potassium concentrations decreased to near constant values below 0.5% at depths greater than 5 feet below the surface. Sulfate at similar depth ranged from 0.5 to 2% in peripheral areas. However, near the topographic low, sulfate reached 4.5% below the thickest salt crust at depths of about 3 feet, and then, along with magnesium and potassium, decreased to less than 1+ or 2% near the surface. In contrast, sulfate concentration in intermediate areas with thin salt crust, peaked near the surface but, magnesium and potassium concentrations peaked at depth. This suggests that the most recent salts precipitated from re-solution brine (generated from dissolution of halite salt crust by rain) were depleted with respect to magnesium and potassium, as compared to the deeper groundwater residuals from ancient Lake Bonneville.

Plankton networks driving carbon export in the oligotrophic ocean

NASA Astrophysics Data System (ADS)

Guidi, L.; Chaffron, S.; Bittner, L.; Eveillard, D.; Raes, J.; Karsenti, E.; Bowler, C.; Gorsky, G.

2016-02-01

The biological carbon pump is the process by which CO2 is transformed to organic carbon via photosynthesis that sinks to the deep ocean as particles where it is sequestered. While the intensity of the pump correlates with plankton community composition, the underlying ecosystem structure and interactions driving the process remain largely uncharacterised. Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve our understanding of the underlying processes. We show that specific plankton communities correlate with carbon export and highlight unexpected and overlooked taxa such as Radiolaria, alveolate parasites, as well as Synechococcus and their phages, as lineages most strongly associated with carbon export in the subtropical oligotrophic ocean. Additionally, we show that the relative abundance of just a few bacterial and viral genes can predict most of the variability in carbon export in these regions. Together these results help elucidate ecosystem drivers of the biological carbon pump and present a case study for scaling from genes-to-ecosystems.

Corrosion protection of steel in ammonia/water heat pumps

DOEpatents

Mansfeld, Florian B.; Sun, Zhaoli

2003-10-14

Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

Destroyer Engineered Operating Cycle (DDEOC), System Maintenance Analysis DDG-37 Class, Salt Water Circulating System SMA 37-106-256, Review of Experience

DTIC Science & Technology

1978-07-01

horizontally mounted, single-end suction, single- stage centrifugal pumps. The rotating elements are mounted on the shaft of the driving motor, and the pump...annual open-and-inspect requirement for MIP E-17/296-21, MRC 21 A14V A. Industrial Facility Improvements -- None IMA Improvements -- None Intergrated ...Circulating Pump, Warren Pumps, Inc., NAVSHIPS 347-3146, January 1959. 4. Technical Manual - Horizontal Close-Co!;pled Pumps Sea (Salt) Water

Engineering microbial biofuel tolerance and export using efflux pumps

PubMed Central

Dunlop, Mary J; Dossani, Zain Y; Szmidt, Heather L; Chu, Hou Cheng; Lee, Taek Soon; Keasling, Jay D; Hadi, Masood Z; Mukhopadhyay, Aindrila

2011-01-01

Many compounds being considered as candidates for advanced biofuels are toxic to microorganisms. This introduces an undesirable trade-off when engineering metabolic pathways for biofuel production because the engineered microbes must balance production against survival. Cellular export systems, such as efflux pumps, provide a direct mechanism for reducing biofuel toxicity. To identify novel biofuel pumps, we used bioinformatics to generate a list of all efflux pumps from sequenced bacterial genomes and prioritized a subset of targets for cloning. The resulting library of 43 pumps was heterologously expressed in Escherichia coli, where we tested it against seven representative biofuels. By using a competitive growth assay, we efficiently distinguished pumps that improved survival. For two of the fuels (n-butanol and isopentanol), none of the pumps improved tolerance. For all other fuels, we identified pumps that restored growth in the presence of biofuel. We then tested a beneficial pump directly in a production strain and demonstrated that it improved biofuel yields. Our findings introduce new tools for engineering production strains and utilize the increasingly large database of sequenced genomes. PMID:21556065

Characterization and regulation of the resistance-nodulation-cell division-type multidrug efflux pumps MdtABC and MdtUVW from the fire blight pathogen Erwinia amylovora.

PubMed

Pletzer, Daniel; Weingart, Helge

2014-07-11

The Gram-negative bacterium Erwinia amylovora is the causal agent of the devastating disease fire blight in rosaceous plants such as apple, pear, quince, raspberry, and cotoneaster. In order to survive and multiply in a host, microbes must be able to circumvent the toxic effects of antimicrobial plant compounds, such as flavonoids and tannins. E. amylovora uses multidrug efflux transporters that recognize and actively export toxic compounds out of the cells. Here, two heterotrimeric resistance-nodulation-cell division (RND)-type multidrug efflux pumps, MdtABC and MdtUVW, from E. amylovora were identified. These RND systems are unusual in that they contain two different RND proteins forming a functional pump. To find the substrate specificities of the two efflux systems, we overexpressed the transporters in a hypersensitive mutant lacking the major RND pump AcrB. Both transporters mediated resistance to several flavonoids, fusidic acid and novobiocin. Additionally, MdtABC mediated resistance towards josamycin, bile salts and silver nitrate, and MdtUVW towards clotrimazole. The ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock was reduced. Quantitative RT-PCR analyses revealed that the expression of the transporter genes was induced during infection of apple rootstock. The polyphenolic plant compound tannin, as well as the heavy metal salt tungstate was found to induce the expression of mdtABC. Finally, the expression of the mdtABC genes was shown to be regulated by BaeR, the response regulator of the two-component system BaeSR, a cell envelope stress response system that controls the adaptive responses to changes in the environment. The expression of MdtABC and MdtUVW is induced during growth of E. amylovora in planta. We identified the plant polyphenol tannin as inducer of mdtABC expression. The reduced ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock suggests that the efflux pumps are involved in resistance to plant antimicrobials, maybe including flavonoids, which were identified as substrates of both pumps. Furthermore, we found that the mdtABC operon belongs to the regulon of the two-component regulator BaeR suggesting a role of this RND transporter in the cell envelope stress response of E. amylovora.

Characterization and regulation of the Resistance-Nodulation-Cell Division-type multidrug efflux pumps MdtABC and MdtUVW from the fire blight pathogen Erwinia amylovora

PubMed Central

2014-01-01

Background The Gram-negative bacterium Erwinia amylovora is the causal agent of the devastating disease fire blight in rosaceous plants such as apple, pear, quince, raspberry, and cotoneaster. In order to survive and multiply in a host, microbes must be able to circumvent the toxic effects of antimicrobial plant compounds, such as flavonoids and tannins. E. amylovora uses multidrug efflux transporters that recognize and actively export toxic compounds out of the cells. Here, two heterotrimeric resistance-nodulation-cell division (RND)-type multidrug efflux pumps, MdtABC and MdtUVW, from E. amylovora were identified. These RND systems are unusual in that they contain two different RND proteins forming a functional pump. Results To find the substrate specificities of the two efflux systems, we overexpressed the transporters in a hypersensitive mutant lacking the major RND pump AcrB. Both transporters mediated resistance to several flavonoids, fusidic acid and novobiocin. Additionally, MdtABC mediated resistance towards josamycin, bile salts and silver nitrate, and MdtUVW towards clotrimazole. The ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock was reduced. Quantitative RT-PCR analyses revealed that the expression of the transporter genes was induced during infection of apple rootstock. The polyphenolic plant compound tannin, as well as the heavy metal salt tungstate was found to induce the expression of mdtABC. Finally, the expression of the mdtABC genes was shown to be regulated by BaeR, the response regulator of the two-component system BaeSR, a cell envelope stress response system that controls the adaptive responses to changes in the environment. Conclusions The expression of MdtABC and MdtUVW is induced during growth of E. amylovora in planta. We identified the plant polyphenol tannin as inducer of mdtABC expression. The reduced ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock suggests that the efflux pumps are involved in resistance to plant antimicrobials, maybe including flavonoids, which were identified as substrates of both pumps. Furthermore, we found that the mdtABC operon belongs to the regulon of the two-component regulator BaeR suggesting a role of this RND transporter in the cell envelope stress response of E. amylovora. PMID:25012600

Seasonal variation in the quality of dissolved and particulate organic matter exchanged between a salt marsh and its adjacent estuary

NASA Astrophysics Data System (ADS)

Osburn, Christopher L.; Mikan, Molly P.; Etheridge, J. Randall; Burchell, Michael R.; Birgand, François

2015-07-01

Fluorescence was used to examine the quality of dissolved and particulate organic matter (DOM and POM) exchanging between a tidal creek in a created salt marsh and its adjacent estuary in eastern North Carolina, USA. Samples from the creek were collected hourly over four tidal cycles in May, July, August, and October 2011. Absorbance and fluorescence of chromophoric DOM (CDOM) and of base-extracted POM (BEPOM) served as the tracers for organic matter quality while dissolved organic carbon (DOC) and base-extracted particulate organic carbon (BEPOC) were used to compute fluxes. Fluorescence was modeled using parallel factor analysis (PARAFAC) and principle components analysis (PCA) of the PARAFAC results. Of nine PARAFAC components (C) modeled, C3 represented recalcitrant DOM and C4 represented fresher soil-derived source DOM. Component 1 represented detrital POM, and C6 represented planktonic POM. Based on mass balance, recalcitrant DOC export was 86 g C m-2 yr-1 and labile DOC export was 49 g C m-2 yr-1; no planktonic DOC was exported. The marsh also exported 41 g C m-2 yr-1 of detrital terrestrial POC, which likely originated from lands adjacent to the North River estuary. Planktonic POC export from the marsh was 6 g C m-2 yr-1. Assuming the exported organic matter was oxidized to CO2 and scaled up to global salt marsh area, respiration of salt marsh DOC and POC transported to estuaries could amount to a global CO2 flux of 11 Tg C yr-1, roughly 4% of the recently estimated CO2 release for marshes and estuaries globally.

Inhibition of bile salt transport by drugs associated with liver injury in primary hepatocytes from human, monkey, dog, rat, and mouse

PubMed Central

Zhang, Jie; He, Kan; Cai, Lining; Chen, Yu-Chuan; Yang, Yifan; Shi, Qin; Woolf, Thomas F.; Ge, Weigong; Guo, Lei; Borlak, Jürgen; Tong, Weida

2018-01-01

Interference of bile salt transport is one of the underlying mechanisms for drug-induced liver injury (DILI). We developed a novel bile salt transport activity assay involving in situ biosynthesis of bile salts from their precursors in primary human, monkey, dog, rat, and mouse hepatocytes in suspension as well as LC-MS/MS determination of extracellular bile salts transported out of hepatocytes. Glycine- and taurine-conjugated bile acids were rapidly formed in hepatocytes and effectively transported into the extracellular medium. The bile salt formation and transport activities were time– and bile-acid-concentration–dependent in primary human hepatocytes. The transport activity was inhibited by the bile salt export pump (BSEP) inhibitors ketoconazole, saquinavir, cyclosporine, and troglitazone. The assay was used to test 86 drugs for their potential to inhibit bile salt transport activity in human hepatocytes, which included 35 drugs associated with severe DILI (sDILI) and 51 with non-severe DILI (non-sDILI). Approximately 60% of the sDILI drugs showed potent inhibition (with IC50 values <50 μM), but only about 20% of the non-sDILI drugs showed this strength of inhibition in primary human hepatocytes and these drugs are associated only with cholestatic and mixed hepatocellular cholestatic (mixed) injuries. The sDILI drugs, which did not show substantial inhibition of bile salt transport activity, are likely to be associated with immune-mediated liver injury. Twenty-four drugs were also tested in monkey, dog, rat and mouse hepatocytes. Species differences in potency were observed with mouse being less sensitive than other species to inhibition of bile salt transport. In summary, a novel assay has been developed using hepatocytes in suspension from human and animal species that can be used to assess the potential for drugs and/or drug-derived metabolites to inhibit bile salt transport and/or formation activity. Drugs causing sDILI, except those by immune-mediated mechanism, are highly associated with potent inhibition of bile salt transport. PMID:27000539

Inhibition of bile salt transport by drugs associated with liver injury in primary hepatocytes from human, monkey, dog, rat, and mouse.

PubMed

Zhang, Jie; He, Kan; Cai, Lining; Chen, Yu-Chuan; Yang, Yifan; Shi, Qin; Woolf, Thomas F; Ge, Weigong; Guo, Lei; Borlak, Jürgen; Tong, Weida

2016-08-05

Interference of bile salt transport is one of the underlying mechanisms for drug-induced liver injury (DILI). We developed a novel bile salt transport activity assay involving in situ biosynthesis of bile salts from their precursors in primary human, monkey, dog, rat, and mouse hepatocytes in suspension as well as LC-MS/MS determination of extracellular bile salts transported out of hepatocytes. Glycine- and taurine-conjugated bile acids were rapidly formed in hepatocytes and effectively transported into the extracellular medium. The bile salt formation and transport activities were time‒ and bile-acid-concentration‒dependent in primary human hepatocytes. The transport activity was inhibited by the bile salt export pump (BSEP) inhibitors ketoconazole, saquinavir, cyclosporine, and troglitazone. The assay was used to test 86 drugs for their potential to inhibit bile salt transport activity in human hepatocytes, which included 35 drugs associated with severe DILI (sDILI) and 51 with non-severe DILI (non-sDILI). Approximately 60% of the sDILI drugs showed potent inhibition (with IC50 values <50 μM), but only about 20% of the non-sDILI drugs showed this strength of inhibition in primary human hepatocytes and these drugs are associated only with cholestatic and mixed hepatocellular cholestatic (mixed) injuries. The sDILI drugs, which did not show substantial inhibition of bile salt transport activity, are likely to be associated with immune-mediated liver injury. Twenty-four drugs were also tested in monkey, dog, rat and mouse hepatocytes. Species differences in potency were observed with mouse being less sensitive than other species to inhibition of bile salt transport. In summary, a novel assay has been developed using hepatocytes in suspension from human and animal species that can be used to assess the potential for drugs and/or drug-derived metabolites to inhibit bile salt transport and/or formation activity. Drugs causing sDILI, except those by immune-mediated mechanism, are highly associated with potent inhibition of bile salt transport. Published by Elsevier Ireland Ltd.

Salinity Tolerance of Two Potato Cultivars (Solanum tuberosum) Correlates With Differences in Vacuolar Transport Activity

PubMed Central

Jaarsma, Rinse; de Boer, Albertus H.

2018-01-01

Potato is an important cultivated crop species and since it is moderately salt sensitive there is a need to develop more salt tolerant cultivars. A high activity of Na+ transport across the tonoplast in exchange for H+ is essential to reduce Na+ toxicity. The proton motive force (PMF) generated by the V-H+-ATPase and the V-H+-PPase energizes the Na+(K+)/H+ antiport. We compared the activity, gene expression, and protein levels of the vacuolar proton pumps and the Na+/H+ antiporters in two potato cultivars (Solanum tuberosum) contrasting in their salt tolerance (cv. Desiree; tolerant and Mozart; sensitive) grown at 0 and 60 mM NaCl. Tonoplast-enriched vesicles were used to study the pump activity and protein levels of the V-H+-ATPase and the V-H+-PPase and the activity of the Na+/H+ antiporter. Although salt stress reduced the V-H+-ATPase and the V-H+-PPase activity in both cultivars, the decline in H+ pump activity was more severe in the salt-sensitive cultivar Mozart. After salt treatment, protein amounts of the vacuolar H+ pumps decreased in Mozart but remained unchanged in the cultivar Desiree. Decreased protein amounts of the V-H+-PPase found in Mozart may explain the reduced V-H+-PPase activity found for Mozart after salt stress. Under non-stress conditions, protein amounts of V-H+-PPase were equal in both cultivars while the V-H+-PPase activity was already twice as high and remained higher after salt treatment in the cultivar Desiree as compared to Mozart. This cultivar-dependent V-H+-PPase activity may explain the higher salt tolerance of Desiree. Moreover, combined with reduced vacuolar H+ pump activity, Mozart showed a lower Na+/H+ exchange activity and the Km for Na+ is at least twofold lower in tonoplast vesicles from Desiree, what suggests that NHXs from Desiree have a higher affinity for Na+ as compared to Mozart. From these results, we conclude that the higher capacity in combination with the higher affinity for Na+ uptake can be an important factor to explain the differences in salt tolerance of these two potato cultivars. PMID:29922314

Salinity Tolerance of Two Potato Cultivars (Solanum tuberosum) Correlates With Differences in Vacuolar Transport Activity.

PubMed

Jaarsma, Rinse; de Boer, Albertus H

2018-01-01

Potato is an important cultivated crop species and since it is moderately salt sensitive there is a need to develop more salt tolerant cultivars. A high activity of Na + transport across the tonoplast in exchange for H + is essential to reduce Na + toxicity. The proton motive force (PMF) generated by the V-H + -ATPase and the V-H + -PPase energizes the Na + (K + )/H + antiport. We compared the activity, gene expression, and protein levels of the vacuolar proton pumps and the Na + /H + antiporters in two potato cultivars ( Solanum tuberosum ) contrasting in their salt tolerance (cv. Desiree; tolerant and Mozart; sensitive) grown at 0 and 60 mM NaCl. Tonoplast-enriched vesicles were used to study the pump activity and protein levels of the V-H + -ATPase and the V-H + -PPase and the activity of the Na + /H + antiporter. Although salt stress reduced the V-H + -ATPase and the V-H + -PPase activity in both cultivars, the decline in H + pump activity was more severe in the salt-sensitive cultivar Mozart. After salt treatment, protein amounts of the vacuolar H + pumps decreased in Mozart but remained unchanged in the cultivar Desiree. Decreased protein amounts of the V-H + -PPase found in Mozart may explain the reduced V-H + -PPase activity found for Mozart after salt stress. Under non-stress conditions, protein amounts of V-H + -PPase were equal in both cultivars while the V-H + -PPase activity was already twice as high and remained higher after salt treatment in the cultivar Desiree as compared to Mozart. This cultivar-dependent V-H + -PPase activity may explain the higher salt tolerance of Desiree. Moreover, combined with reduced vacuolar H + pump activity, Mozart showed a lower Na + /H + exchange activity and the K m for Na + is at least twofold lower in tonoplast vesicles from Desiree, what suggests that NHXs from Desiree have a higher affinity for Na + as compared to Mozart. From these results, we conclude that the higher capacity in combination with the higher affinity for Na + uptake can be an important factor to explain the differences in salt tolerance of these two potato cultivars.

Response to Bile Salts in Clinical Strains of Acinetobacter baumannii Lacking the AdeABC Efflux Pump: Virulence Associated with Quorum Sensing

PubMed Central

López, Maria; Blasco, Lucia; Gato, Eva; Perez, Astrid; Fernández-Garcia, Laura; Martínez-Martinez, Luis; Fernández-Cuenca, Felipe; Rodríguez-Baño, Jesús; Pascual, Alvaro; Bou, German; Tomás, Maria

2017-01-01

Introduction: Acinetobacter baumannii is an opportunistic nosocomial pathogen associated with multiple infections. This pathogen usually colonizes (first stage of microbial infection) host tissues that are in contact with the external environment. As one of the sites of entry in human hosts is the gastrointestinal tract, the pathogen must be capable of tolerating bile salts. However, studies analyzing the molecular characteristics involved in the response to bile salts in clinical strains of A. baumannii are scarce. Material and Methods: Microbiological and transcriptional studies (arrays and RT-PCR) in the response to bile salts were carried out in isogenic (A. baumanni ΔadeB ATCC 17978 and A. baumannii ΔadeL ATCC 17978) and clinical strains from clone ST79/PFGE-HUI-1 which is characterized by lacking the AdeABC efflux pump and by overexpression the AdeFGH efflux pump. Results and Discussion: In presence of bile salts, in addition to the glutamate/aspartate transporter were found overexpressed in A. baumannii ΔadeB ATCC 17978, the virulence factors (surface motility, biofilm, and Type VI Secretion System) which are associated with activation of the Quorum Sensing system. Overexpression of these factors was confirmed in clinical strains of clone ST79/PFGE-HUI-1. Conclusions: This the first study about the adaptive response to bile salts investigating the molecular and microbiological characteristics in response to bile salts of an isogenic model of A. baumannii ATCC 17978 and clinical isolates of A. baumannii (clinical strains of ST79/PFGE-HUI-1) lacking the main RND efflux pump (AdeABC). Clinical isolates of A. baumannii lacking the AdeABC efflux pump (clone ST79/PFGE-HUI-1) displayed a new clinical profile (increased invasiveness) possibly associated with the response to stress conditions (such as the presence of bile salts). PMID:28536672

What Controls Submarine Groundwater Discharge?

NASA Astrophysics Data System (ADS)

Martin, J. B.; Cable, J. E.; Cherrier, J.; Roy, M.; Smith, C. G.; Dorsett, A.

2008-05-01

Numerous processes have been implicated in controlling submarine groundwater discharge (SGD) to coastal zones since Ghyben, Herzberg and Dupuit developed models of fresh water discharge from coastal aquifers at the turn of the 19th century. Multiple empirical and modeling techniques have also been applied to these environments to measure the flow. By the mid-1950's, Cooper had demonstrated that dispersion across the fresh water-salt water boundary required salt water entrained into fresh water flow be balanced by recharge of salt water across the sediment-water interface seaward of the outflow face. Percolation of water into the beach face from wind and tidal wave run up and changes in pressure at the sediment-water interface with fluctuating tides have now been recognized, and observed, as processes driving seawater into the sediments. Within the past few years, variations in water table levels and the 1:40 amplification from density difference in fresh water and seawater have been implicated to pump salt water seasonally across the sediment- water interface. Salt water driven by waves, tides and seasonal water table fluctuations is now recognized as a component of SGD when it flows back to overlying surface waters. None of these processes are sufficiently large to provide measured volumes of SGD in Indian River Lagoon, Florida, however, because minimal tides and waves exist, flat topography and transmissive aquifers minimize fluctuations of the water table, and little water is entrained across the salt water-fresh water boundary. Nonetheless, the saline fraction of SGD represents more than 99% of the volume of total SGD in the Indian River Lagoon. This volume of saline SGD can be driven by the abundance of burrowing organisms in the lagoon, which pump sufficient amounts of water through the sediment- water interface. These bioirrigating organisms are ubiquitous at all water depths in sandy sediment and thus may provide one of the major sources of SGD world wide. Because bioirrigated water is well oxygenated and passes through sedimentary pore spaces, its influence may be quite large on fluxes of diagenetic reactive components, including organic matter, nutrients, and redox sensitive metals. While fresh meteoric groundwater may be confined to the shoreline in most cases and delivers new material from continents to the ocean, seawater circulating through sediments as part of SGD is apparently a much greater fraction of the total water flux and hence has the potential to significantly impact sediment diagenetic processes and subsequent export of nutrients and other solutes from the sediment to the water column.

Seasonal Variation in the Quality of Dissolved and Particulate Organic Matter Exchanged Between a Salt Marsh and Its Adjacent Estuary

NASA Astrophysics Data System (ADS)

Osburn, C. L.; Mikan, M.; Etheridge, J. R.; Burchell, M. R.; Birgand, F.

2015-12-01

Salt marshes are transitional ecosystems between terrestrial and marine environments. Along with mangroves and other vegetated coastal habitats, salt marshes rank among the most productive ecosystems on Earth, with critical global importance for the planet's carbon cycle. Fluorescence was used to examine the quality of dissolved and particulate organic matter (DOM and POM) exchanging between a tidal creek in a created salt marsh and its adjacent estuary in eastern North Carolina, USA. Samples from the creek were collected hourly over four tidal cycles in May, July, August, and October of 2011. Absorbance and fluorescence of chromophoric DOM (CDOM) and of base-extracted POM (BEPOM) served as the tracers for organic matter quality while dissolved organic carbon (DOC) and base-extracted particulate organic carbon (BEPOC) were used to compute fluxes. Fluorescence was modeled using parallel factor analysis (PARAFAC) and principle components analysis (PCA) of the PARAFAC results. Of nine PARAFAC components modeled, we used multiple linear regression to identify tracers for recalcitrant DOM; labile soil-derived source DOM; detrital POM; and planktonic POM. Based on mass balance, recalcitrant DOC export was 86 g C m-2 yr-1 and labile DOC export was 49 g C m-2 yr-1. The marsh also exported 41 g C m-2 yr-1 of detrital terrestrial POC, which likely originated from lands adjacent to the North River estuary. Planktonic POC export from the marsh was 6 g C m-2 yr-1. Using the DOM and POM quality results obtained via fluorescence measurements and scaling up to global salt marsh area, we estimated that the potential release of CO2 from the respiration of salt marsh DOC and POC transported to estuaries could be 11 Tg C yr-1, roughly 4% of the recently estimated CO2 release for marshes and estuaries globally.

The dynamic ocean biological pump: Insights from a global compilation of particulate organic carbon, CaCO3, and opal concentration profiles from the mesopelagic

NASA Astrophysics Data System (ADS)

Lam, Phoebe J.; Doney, Scott C.; Bishop, James K. B.

2011-09-01

We have compiled a global data set of 62 open ocean profiles of particulate organic carbon (POC), CaCO3, and opal concentrations collected by large volume in situ filtration in the upper 1000 m over the last 30 years. We define concentration-based metrics for the strength (POC concentration at depth) and efficiency (attenuation of POC with depth in the mesopelagic) of the biological pump. We show that the strength and efficiency of the biological pump are dynamic and are characterized by a regime of constant and high transfer efficiency at low to moderate surface POC and a bloom regime where the height of the bloom is characterized by a weak deep biological pump and low transfer efficiency. The variability in POC attenuation length scale manifests in a clear decoupling between the strength of the shallow biological pump (e.g., POC at the export depth) and the strength of the deep biological pump (POC at 500 m). We suggest that the paradigm of diatom-driven export production is driven by a too restrictive perspective on upper mesopelagic dynamics. Indeed, our full mesopelagic analysis suggests that large, blooming diatoms have low transfer efficiency and thus may not export substantially to depth; rather, our analysis suggests that ecosystems characterized by smaller cells and moderately high %CaCO3 have a high mesopelagic transfer efficiency and can have higher POC concentrations in the deep mesopelagic even with relatively low surface or near-surface POC. This has negative implications for the carbon sequestration prospects of deliberate iron fertilization.

System design description of forced-convection molten-salt corrosion loops MSR-FCL-3 and MSR-FCL-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huntley, W.R.; Silverman, M.D.

1976-11-01

Molten-salt corrosion loops MSR-FCL-3 and MSR-FCL-4 are high-temperature test facilities designed to evaluate corrosion and mass transfer of modified Hastelloy N alloys for future use in Molten-Salt Breeder Reactors. Salt is circulated by a centrifugal sump pump to evaluate material compatibility with LiF-BeF/sub 2/-ThF/sub 4/-UF/sub 4/ fuel salt at velocities up to 6 m/s (20 fps) and at salt temperatures from 566 to 705/sup 0/C (1050 to 1300/sup 0/F). The report presents the design description of the various components and systems that make up each corrosion facility, such as the salt pump, corrosion specimens, salt piping, main heaters, salt coolers,more » salt sampling equipment, and helium cover-gas system, etc. The electrical systems and instrumentation and controls are described, and operational procedures, system limitations, and maintenance philosophy are discussed.« less

76 FR 16842 - Request for a License To Export Reactor Components

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-25

... NUCLEAR REGULATORY COMMISSION Request for a License To Export Reactor Components Pursuant to 10.... Mechanical Corporation. coolant pump 1000 (design) maintenance, and systems, related reactors. operation of AP- equipment, and 1000 (design) spare parts. nuclear reactors. February 10, 2011 February 23, 2011...

Antibiotic Resistance Mediated by the MacB ABC Transporter Family: A Structural and Functional Perspective.

PubMed

Greene, Nicholas P; Kaplan, Elise; Crow, Allister; Koronakis, Vassilis

2018-01-01

The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space. In the MacAB-TolC tripartite pump, mechanotransmission drives efflux of antibiotics and export of a protein toxin from the periplasmic space via the TolC exit duct. Homologous tripartite systems from pathogenic bacteria similarly export protein-like signaling molecules, virulence factors and siderophores. In addition, many MacB-like ABC transporters do not form tripartite pumps, but instead operate in diverse cellular processes including antibiotic sensing, cell division and lipoprotein trafficking.

Hydrology and Salt Balance in a Large, Hypersaline Coastal Lagoon: Lagoa de Araruama, Brazil

NASA Astrophysics Data System (ADS)

Kjerfve, Björn; Schettini, C. A. F.; Knoppers, Bastiaan; Lessa, Guilherme; Ferreira, H. O.

1996-06-01

Lagoa de Araruama in the state of Rio de Janeiro, Brazil, is a hypersaline coastal lagoon as a result of semi-arid climate conditions, a small drainage basin and a choked entrance channel. The lagoon has been continuously hypersaline for at least 4·5 centuries, but the mean salinity has varied substantially. It has recently decreased from 57 to 52 as indicated by density (salinity) measurements between 1965 and 1990. Analysis of more than 20 years of salinity time series data, in addition to monthly lagoon cruises to measure the spatial salinity distribution, indicate that the lagoon salinity largely fluctuates in response to the difference between evaporation and precipitation. The major factor explaining the long-term trend of decreasing salinity in the lagoon is the constant pumping of 1 m 3s -1of freshwater to the communities surrounding the lagoon from an adjacent watershed, and subsequent discharge of this water into Lagoa de Araruama. The net salt budget is primarily a balance between the advective import of salt from the coastal ocean and eddy diffusive export of salt to the ocean, although the extensive mining of salt from the lagoon during past decades is also a small but significant contribution to the salt budget. The flushing half-life is proposed as a useful time scale of water exchange, is calculated based on a combination of hydrological and tidal processes, and is excellent for comparison of lagoons and assessing water quality changes. The flushing half-life measures 83·5 days for Lagoa de Araruama, considerably longer than for most other coastal lagoons. The proposed dredging of a second ocean channel to Lagoa de Araruama is probably not a good idea. It is likely to accelerate the decrease of lagoon salinity and somewhat improve the lagoon water exchange. At the same time, this will eliminate the apparent buffering capacity provided by the hypersaline environment, and thus may potentially cause water quality problems.

Global patterns of organic carbon export and sequestration in the ocean (Arne Richter Award for Outstanding Young Scientists)

NASA Astrophysics Data System (ADS)

Henson, S.; Sanders, R.; Madsen, E.; Le Moigne, F.; Quartly, G.

2012-04-01

A major term in the global carbon cycle is the ocean's biological carbon pump which is dominated by sinking of small organic particles from the surface ocean to its interior. Here we examine global patterns in particle export efficiency (PEeff), the proportion of primary production that is exported from the surface ocean, and transfer efficiency (Teff), the fraction of exported organic matter that reaches the deep ocean. This is achieved through extrapolating from in situ estimates of particulate organic carbon export to the global scale using satellite-derived data. Global scale estimates derived from satellite data show, in keeping with earlier studies, that PEeff is high at high latitudes and low at low latitudes, but that Teff is low at high latitudes and high at low latitudes. However, in contrast to the relationship observed for deep biomineral fluxes in previous studies, we find that Teff is strongly negatively correlated with opal export flux from the upper ocean, but uncorrelated with calcium carbonate export flux. We hypothesise that the underlying factor governing the spatial patterns observed in Teff is ecosystem function, specifically the degree of recycling occurring in the upper ocean, rather than the availability of calcium carbonate for ballasting. Finally, our estimate of global integrated carbon export is only 50% of previous estimates. The lack of consensus amongst different methodologies on the strength of the biological carbon pump emphasises that our knowledge of a major planetary carbon flux remains incomplete.

Bile Formation and Secretion

PubMed Central

Boyer, James L.

2014-01-01

Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (~1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions. PMID:23897680

Impact of the natural Fe-fertilization on the magnitude, stoichiometry and efficiency of particulate biogenic silica, nitrogen and iron export fluxes

NASA Astrophysics Data System (ADS)

Lemaitre, N.; Planquette, H.; Dehairs, F.; van der Merwe, P.; Bowie, A. R.; Trull, T. W.; Laurenceau-Cornec, E. C.; Davies, D.; Bollinger, C.; Le Goff, M.; Grossteffan, E.; Planchon, F.

2016-11-01

The Kerguelen Plateau is characterized by a naturally Fe-fertilized phytoplankton bloom that extends more than 1000 km downstream in the Antarctic Circumpolar Current. During the KEOPS2 study, in austral spring, we measured particulate nitrogen (PN), biogenic silica (BSi) and particulate iron (PFe) export fluxes in order to investigate how the natural fertilization impacts the stoichiometry and the magnitude of export fluxes and therefore the efficiency of the biological carbon pump. At 9 stations, we estimated elemental export fluxes based on element concentration to 234Th activity ratios for particulate material collected with in-situ pumps and 234Th export fluxes (Planchon et al., 2015). This study revealed that the natural Fe-fertilization increased export fluxes but to variable degrees. Export fluxes for the bloom impacted area were compared with those of a high-nutrient, low-chlorophyll (HNLC), low-productive reference site located to the south-west of Kerguelen and which had the lowest BSi and PFe export fluxes (2.55 mmol BSi m-2 d-1 and 1.92 μmol PFem-2 d-1) and amongst the lowest PN export flux (0.73 mmol PN m-2 d-1). The impact of the Fe fertilization was the greatest within a meander of the polar front (PF), to the east of Kerguelen, with fluxes reaching 1.26 mmol PN m-2 d-1; 20.4 mmol BSi m-2 d-1 and 22.4 μmol PFe m-2 d-1. A highly productive site above the Kerguelen Plateau, on the contrary, was less impacted by the fertilization with export fluxes reaching 0.72 mmol PN m-2 d-1; 4.50 mmol BSi m-2 d-1 and 21.4 μmol PFe m-2 d-1. Our results suggest that ecosystem features (i.e. type of diatom community) could play an important role in setting the magnitude of export fluxes of these elements. Indeed, for the PF meander, the moderate productivity was sustained by the presence of large and strongly silicified diatom species while at the higher productivity sites, smaller and slightly silicified diatoms dominated. Interestingly, our results suggest that PFe export fluxes can be driven by the lithogenic pool of particles, especially over the Plateau where such inputs from the sediments are important. Finally, for the Plateau and the PF meander, the comparison between PFe export and the particulate PFe stock integrated over the mixed layer depth revealed an efficient PFe export out of the mixed layer at these sites. Export efficiencies (i.e. the ratio between export and uptake) exhibit a very efficient silica pump especially at the HNLC reference station where heavily silicified diatoms were present. On the contrary, the increase with depth of the C:N ratio and the low nitrogen export efficiencies support the idea of a strong remineralization and nitrification activity.

Salt sensitivity in normotensives with family history of hypertension: studies of membrane transport, intracellular electrolytes and alpha 2-adrenergic receptors.

PubMed

Skrabal, F; Gruber, G; Meister, B; Ledochowski, M; Doll, P; Lang, F; Cerny, E

1985-12-01

Using long-term automatic blood pressure recording it has previously been shown that subjects with family history of hypertension show a minute fall of blood pressure during sodium restriction, which is reversible by high sodium intake. Thus normotensives with hypertensive antecedents as a group are salt-sensitive, whereas normotensives without heredity of hypertension as a group are salt-resistant. The present study compares intracellular sodium, potassium and calcium, sodium pump activity, NaK-cotransport of red blood cells and density and affinity of alpha 2-adrenergic receptors of platelets in normotensive subjects classified according to family history of hypertension and according to 'salt sensitivity' and 'salt resistance'. Neither the family history of hypertension nor salt sensitivity correlated with intracellular sodium, potassium, calcium, Na-pump activity and NaK-cotransport. Alpha 2-adrenergic density was higher in salt-sensitive than in salt-resistant subjects (P < 0.05) but similar in subjects with a positive and negative family history of hypertension. However, alpha 2-adrenergic receptor density decreased significantly during 2 weeks of moderate salt restriction from 169.6 +/- 34.2 to 142.6 +/- 30.8 (P < 0.01, paired t-test), which may explain the decreased pressor response to infused noradrenaline observed in a previous study during moderate salt restriction. It is concluded that in humans there is no association of genetic predisposition of hypertension or of salt sensitivity to an alteration of sodium pump activity, NaK-cotransport, intracellular sodium and calcium. Alpha 2-receptor density of platelets deserves further study as a possible predictor of salt sensitivity in normotensives.

77 FR 39521 - Application for a License To Export Nuclear Reactor Major Components and Equipment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-03

... LLC reactor coolant equipment for four constructing four plant May 14, 2012 pumps with motors, APR1400... Emirates. XR176 monitoring and plant in Braka. 110060011 control equipment, auxiliary equipment and... NUCLEAR REGULATORY COMMISSION Application for a License To Export Nuclear Reactor Major Components...

Modeling of Dense Water Production and Salt Transport from Alaskan Coastal Polynyas

NASA Technical Reports Server (NTRS)

Signorini, Sergio R.; Cavalieri, Donald J.

2000-01-01

The main significance of this paper is that a realistic, three-dimensional, high-resolution primitive equation model has been developed to study the effects of dense water formation in Arctic coastal polynyas. The model includes realistic ambient stratification, realistic bottom topography, and is forced by time-variant surface heat flux, surface salt flux, and time-dependent coastal flow. The salt and heat fluxes, and the surface ice drift, are derived from satellite observations (SSM/I and NSCAT sensors). The model is used to study the stratification, salt transport, and circulation in the vicinity of Barrow Canyon during the 1996/97 winter season. The coastal flow (Alaska coastal current), which is an extension of the Bering Sea throughflow, is formulated in the model using the wind-transport regression. The results show that for the 1996/97 winter the northeastward coastal current exports 13% to 26% of the salt produced by coastal polynyas upstream of Barrow Canyon in 20 to 30 days. The salt export occurs more rapidly during less persistent polynyas. The inclusion of ice-water stress in the model makes the coastal current slightly weaker and much wider due to the combined effects of surface drag and offshore Ekman transport.

The ebb and flood of Silica: Quantifying dissolved and biogenic silica fluxes from a temperate salt marsh

NASA Astrophysics Data System (ADS)

Vieillard, Amanda M.; Fulweiler, Robinson W.; Hughes, Zoe J.; Carey, Joanna C.

2011-12-01

Salt marshes are widely studied due to the broad range of ecosystem services they provide including serving as crucial wildlife habitat and as hotspots for biogeochemical cycling. Nutrients such as nitrogen (N), phosphorus (P), and carbon (C) are well studied in these systems. However, salt marshes may also be important environments for the cycling of another key nutrient, silica (Si). Found at the land-sea interface, these systems are silica replete with large stocks in plant biomass, sediments, and porewater, and therefore, have the potential to play a substantial role in the transformation and export of silica to coastal waters. In an effort to better understand this role, we measured the fluxes of dissolved (DSi) and biogenic (BSi) silica into and out of two tidal creeks in a temperate, North American (Rowley, Massachusetts, USA) salt marsh. One of the creeks has been fertilized from May to September for six years allowing us to examine the impacts of nutrient addition on silica dynamics within the marsh. High-resolution sampling in July 2010 showed no significant differences in Si concentrations between the fertilized and reference creeks with dissolved silica ranging from 0.5 to 108 μM and biogenic from 2.0 to 56 μM. Net fluxes indicated that the marsh is a point source of dissolved silica to the estuary in the summer with a net flux of approximately 169 mol h -1, demonstrating that this system exports DSi on the same magnitude as some nearby, mid-sized rivers. If these findings hold true for all salt marshes, then these already valuable regions are contributing yet another ecosystem service that has been previously overlooked; by exporting DSi to coastal receiving waters, salt marshes are actively providing this important nutrient for coastal primary productivity.

Antibiotic Resistance Mediated by the MacB ABC Transporter Family: A Structural and Functional Perspective

PubMed Central

Greene, Nicholas P.; Kaplan, Elise; Crow, Allister; Koronakis, Vassilis

2018-01-01

The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space. In the MacAB-TolC tripartite pump, mechanotransmission drives efflux of antibiotics and export of a protein toxin from the periplasmic space via the TolC exit duct. Homologous tripartite systems from pathogenic bacteria similarly export protein-like signaling molecules, virulence factors and siderophores. In addition, many MacB-like ABC transporters do not form tripartite pumps, but instead operate in diverse cellular processes including antibiotic sensing, cell division and lipoprotein trafficking. PMID:29892271

JPRS Report, Near East & South Asia

DTIC Science & Technology

1988-01-28

Israel’s peace in first instance. Having guar - anteed the Jewish state the separate peace it wanted with Egypt, the United States paid no attention to...plant gums , marine prod- ucts, wool and yarn have decreased. This decrease has been compensated by the great increase in the export of dried goods...mentioned session, the requests of the "Tuli Pers" company to export 3,000 tons of powdered detergent and the Pars pump company to export 1,500

Carbon fluxes in the Arabian Sea: Export versus recycling

NASA Astrophysics Data System (ADS)

Rixen, Tim; Gaye, Birgit; Ramaswamy, Venkitasubramani

2016-04-01

The organic carbon pump strongly influences the exchange of carbon between the ocean and the atmosphere. It is known that it responds to global change but the magnitude and the direction of change are still unpredictable. Sediment trap experiments carried out at various sites in the Arabian Sea between 1986 and 1998 have shown differences in the functioning of the organic carbon pump (OCP). An OCP driven by eukaryotic phytoplankton operated in the upwelling region off Oman and during the spring bloom in the northern Arabian Sea. Cyanobacteria capable of fixing nitrogen seem to dominate the phytoplankton community during all other seasons. The export driven by cyanobacteria was much lower than the export driven by eukaryotic phytoplankton. Productivity and nutrient availability seems to be a main factor controlling fluxes during blooms of eukaryotic phytoplankton. The ballast effect caused by inputs of dust into the ocean and its incorporation into sinking particles seems to be the main factor controlling the export during times when cyanobacteria dominate the phytoplankton community. C/N ratios of organic matter exported from blooms dominated by nitrogen fixing cyanobacteria are enhanced and, furthermore, indicate a more efficient recycling of nutrients at shallower water depth. This implies that the bacterial-driven OCP operates more in a recycling mode that keeps nutrients closer to the euphotic zone whereas the OCP driven by eukaryotic phytoplankton reduces the recycling of nutrients by exporting them into greater water-depth.

The pump, the exchanger, and the holy spirit: origins and 40-year evolution of ideas about the ouabain-Na+ pump endocrine system.

PubMed

Blaustein, Mordecai P

2018-01-01

Two prescient 1953 publications set the stage for the elucidation of a novel endocrine system: Schatzmann's report that cardiotonic steroids (CTSs) are all Na + pump inhibitors, and Szent-Gyorgi's suggestion that there is an endogenous "missing screw" in heart failure that CTSs like digoxin may replace. In 1977 I postulated that an endogenous Na + pump inhibitor acts as a natriuretic hormone and simultaneously elevates blood pressure (BP) in salt-dependent hypertension. This hypothesis was based on the idea that excess renal salt retention promoted the secretion of a CTS-like hormone that inhibits renal Na + pumps and salt reabsorption. The hormone also inhibits arterial Na + pumps, elevates myocyte Na + and promotes Na/Ca exchanger-mediated Ca 2+ gain. This enhances vasoconstriction and arterial tone-the hallmark of hypertension. Here I describe how those ideas led to the discovery that the CTS-like hormone is endogenous ouabain (EO), a key factor in the pathogenesis of hypertension and heart failure. Seminal observations that underlie the still-emerging picture of the EO-Na + pump endocrine system in the physiology and pathophysiology of multiple organ systems are summarized. Milestones include: 1) cloning the Na + pump isoforms and physiological studies of mutated pumps in mice; 2) discovery that Na + pumps are also EO-triggered signaling molecules; 3) demonstration that ouabain, but not digoxin, is hypertensinogenic; 4) elucidation of EO's roles in kidney development and cardiovascular and renal physiology and pathophysiology; 5) discovery of "brain ouabain", a component of a novel hypothalamic neuromodulatory pathway; and 6) finding that EO and its brain receptors modulate behavior and learning.

Salt tolerance at single cell level in giant-celled Characeae

PubMed Central

Beilby, Mary J.

2015-01-01

Characean plants provide an excellent experimental system for electrophysiology and physiology due to: (i) very large cell size, (ii) position on phylogenetic tree near the origin of land plants and (iii) continuous spectrum from very salt sensitive to very salt tolerant species. A range of experimental techniques is described, some unique to characean plants. Application of these methods provided electrical characteristics of membrane transporters, which dominate the membrane conductance under different outside conditions. With this considerable background knowledge the electrophysiology of salt sensitive and salt tolerant genera can be compared under salt and/or osmotic stress. Both salt tolerant and salt sensitive Characeae show a rise in membrane conductance and simultaneous increase in Na+ influx upon exposure to saline medium. Salt tolerant Chara longifolia and Lamprothamnium sp. exhibit proton pump stimulation upon both turgor decrease and salinity increase, allowing the membrane PD to remain negative. The turgor is regulated through the inward K+ rectifier and 2H+/Cl- symporter. Lamprothamnium plants can survive in hypersaline media up to twice seawater strength and withstand large sudden changes in salinity. Salt sensitive C. australis succumbs to 50–100 mM NaCl in few days. Cells exhibit no pump stimulation upon turgor decrease and at best transient pump stimulation upon salinity increase. Turgor is not regulated. The membrane PD exhibits characteristic noise upon exposure to salinity. Depolarization of membrane PD to excitation threshold sets off trains of action potentials, leading to further loses of K+ and Cl-. In final stages of salt damage the H+/OH- channels are thought to become the dominant transporter, dissipating the proton gradient and bringing the cell PD close to 0. The differences in transporter electrophysiology and their synergy under osmotic and/or saline stress in salt sensitive and salt tolerant characean cells are discussed in detail. PMID:25972875

ABCB4 missense mutations D243A, K435T, G535D, I490T, R545C, and S978P significantly impair the lipid floppase and likely predispose to secondary pathologies in the human population.

PubMed

Andress, Edward J; Nicolaou, Michael; McGeoghan, Farrell; Linton, Kenneth J

2017-07-01

Bile salts are natural detergents required to solubilise dietary fat and lipid soluble vitamins. They are synthesised in hepatocytes and secreted into the luminal space of the biliary tree by the bile salt export pump (BSEP), an ATP-binding cassette (ABC) transporter in the canalicular membrane. BSEP deficiency causes cytotoxic accumulation of bile salts in the hepatocyte that results in mild-to-severe forms of cholestasis. The resulting inflammation can also progress to hepatocellular cancer via a novel mechanism involving upregulation of proliferative signalling pathways. A second ABC transporter of the canalicular membrane is also critical for bile formation. ABCB4 flops phosphatidylcholine into the outer leaflet of the membrane to be extracted by bile salts in the canalicular space. These mixed micelles reduce the detergent action of the bile salts and protect the biliary tree from their cytotoxic activity. ABCB4 deficiency also causes cholestasis, and might be expected to cause cholangitis and predispose to liver cancer. Non-synonymous SNPs in ABCB4 have now been described in patients with liver cancer or with inflammatory liver diseases that are known to predispose to cancer, but data showing that the SNPs are sufficiently deleterious to be an etiological factor are lacking. Here, we report the first characterisation at the protein level of six ABCB4 variants (D243A, K435T, G535D, I490T, R545C, and S978P) previously found in patients with inflammatory liver diseases or liver cancer. All significantly impair the transporter with a range of phenotypes exhibited, including low abundance, intracellular retention, and reduced floppase activity, suggesting that ABCB4 deficiency is the root cause of the pathology in these cases.

Import and export fluxes of macrozooplankton are taxa- and season-dependent at Jiuduansha marsh, Yangtze River estuary

NASA Astrophysics Data System (ADS)

Qin, Haiming; Sheng, Qiang; Chu, Tianjiang; Wang, Sikai; Wu, Jihua

2015-09-01

Macrozooplankton may play important roles in influencing nutrient exchange between salt marsh and nearby estuarine ecosystems through predator-prey interactions and their transport by tidal flows. In this study, macrozooplankton transport through year-round monthly sampling was investigated in a salt marsh creek of the Yangtze River estuary. Twenty-one orders of macrozooplankton were captured. Calanoida and Decapoda were dominant and numerically comprised 59.59% and 37.59% respectively of the total captured macrozooplankton throughout the year. Decapoda mainly occurred in April, May and June. In other months, the Calanoida contributed over 90% of the total individuals. The annual Ferrari index (I) for total individual number of macrozooplankton was 0.27, which generally supports the viewpoint that salt marshes are sources of zooplankton. The salt marsh was mainly a source for decapods and mysids, possibly because of larval release in their breeding seasons. The marsh was also a source for amphipods, probably because some benthic forms became transient planktonic forms during tidal water flushing. Copepods and fish larvae exhibited net import into the salt marsh, which may result from predation from salt marsh settlers or retention in the salt marsh. Monthly Ferrari index (I) estimations revealed that the role of the salt marsh as a sink or source of macrozooplankton was time-dependent, which is related to the life history of animals. This study showed that whether the salt marsh zooplankton act as energy importers or exporters is group/taxa-dependent and time-dependent.

46 CFR 182.520 - Bilge pumps.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Highly resistant to salt water, petroleum oil, heat, and vibration. (g) If a fixed hand pump is used to... 46 Shipping 7 2010-10-01 2010-10-01 false Bilge pumps. 182.520 Section 182.520 Shipping COAST...) MACHINERY INSTALLATION Bilge and Ballast Systems § 182.520 Bilge pumps. (a) A vessel must be provided with...

Schedule of controlled substances; placement of fospropofol into schedule IV. Final rule.

PubMed

2009-10-06

With the issuance of this final rule, the Deputy Administrator of the Drug Enforcement Administration (DEA) places the substance fospropofol, including its salts, isomers and salts of isomers whenever the existence of such salts, isomers, and salts of isomers is possible, into schedule IV of the Controlled Substances Act (CSA). As a result of this rule, the regulatory controls and criminal sanctions of schedule IV will be applicable to the manufacture, distribution, dispensing, importation, and exportation of fospropofol and products containing fospropofol.

78 FR 42753 - Materials Technical Advisory Committee; Notice of Partially Closed Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-17

... BIS senior management and export control reform update including the proposed Routed Export....'' 4. Report of Composite Working Group and discussion on (1) feasibility of universal test for modulus... values for 1C008-10,1C210, and 1C990. 5. Report of Biological and Pump/Valves Working Group. 6. Report on...

Spatial variability of upper ocean POC export in the Bay of Bengal and the Indian Ocean determined using particle-reactive 234Th

NASA Astrophysics Data System (ADS)

Subha Anand, S.; Rengarajan, R.; Sarma, V. V. S. S.; Sudheer, A. K.; Bhushan, R.; Singh, S. K.

2017-05-01

The northern Indian Ocean is globally significant for its seasonally reversing winds, upwelled nutrients, high biological production, and expanding oxygen minimum zones. The region acts as sink and source for atmospheric CO2. However, the efficiency of the biological carbon pump to sequester atmospheric CO2 and export particulate organic carbon from the surface is not well known. To quantify the upper ocean carbon export flux and to estimate the efficiency of biological carbon pump in the Bay of Bengal and the Indian Ocean, seawater profiles of total 234Th were measured from surface to 300 m depth at 13 stations from 19.9°N to 25.3°S in a transect along 87°E, during spring intermonsoon period (March-April 2014). Results showed enhanced in situ primary production in the equatorial Indian Ocean and the central Bay of Bengal and varied from 13.2 to 173.8 mmol C m-2 d-1. POC export flux in this region varied from 0 to 7.7 mmol C m-2 d-1. Though high carbon export flux was found in the equatorial region, remineralization of organic carbon in the surface and subsurface waters considerably reduced organic carbon export in the Bay of Bengal. Annually recurring anticyclonic eddies enhanced organic carbon utilization and heterotrophy. Oxygen minimum zone developed due to stratification and poor ventilation was intensified by subsurface remineralization. 234Th-based carbon export fluxes were not comparable with empirical statistical model estimates based on primary production and temperature. Region-specific refinement of model parameters is required to accurately predict POC export fluxes.

Progressive familial intrahepatic cholestasis type 1.

PubMed

Paulusma, Coen C; Elferink, Ronald P J Oude; Jansen, Peter L M

2010-05-01

Progressive familial intrahepatic cholestasis type 1 is a rare genetic liver disease that presents in the first year of life. Bile salts are elevated and these patients are often jaundiced. Despite the cholestasis, serum gamma-glutamyltransferase activity is normal or reduced. Pruritus is a major symptom in these patients. Partial external biliary diversion is helpful in several patients as it reduces the pruritus and postpones or even avoids liver transplantation. The disease is caused by mutations in the gene ATP8B1 that preclude the normal expression of ATP8B1. ATP8B1 is a protein that acts as a lipid flippase, transporting phosphatidylserine from the exoplasmic to the cytoplasmic leaflet of the canalicular membrane of hepatocytes. The authors have shown that the canalicular membrane of ATP8B1-deficient hepatocytes is less stable as evidenced by enhanced extraction of membrane constituents by bile salts. Recent evidence suggests membrane instability in ATP8B1-deficient hair cells of the ear, providing an explanation for hearing loss in ATP8B1 deficiency. Although the exact etiology of cholestasis is incompletely understood, it is hypothesized that ATP8B1 deficiency results in enhanced cholesterol extraction from the canalicular membrane, which impairs the function of the bile salt export pump (BSEP), resulting in cholestasis. Mutations in ATP8B1 also cause benign recurrent intrahepatic cholestasis, a milder variant of the disease characterized by episodes of cholestasis. The onset and resolution of the cholestatic episodes in these patients is still not well understood.

Co-overexpressing a plasma membrane and a vacuolar membrane sodium/proton antiporter significantly improves salt tolerance in transgenic Arabidopsis plants.

USDA-ARS?s Scientific Manuscript database

The Arabidopsis gene AtNHX1 encodes a vacuolar membrane bound sodium/proton (Sodium/Hydrogen) antiporter that transports sodium into the vacuole and exports hydrogen into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane bound sodium/hydrogen antiporter that exports sodium to the ex...

Resolving the Intricacies of Lateral Exports of Inorganic Carbon and Alkalinity from Coastal Salt Marshes

NASA Astrophysics Data System (ADS)

Wang, A. Z.; Chu, S. N.; Kroeger, K. D.; Gonneea, M. E.; Ganju, N. K.

2017-12-01

Dynamic lateral exports of dissolved inorganic carbon (DIC) and total alkalinity (Alk) via tidal exchange from highly productive intertidal marshes are an important piece of puzzle in the coastal carbon cycle, challenging our capability of assessing coastal carbon budgets and projecting future changes under anthropogenic pressure. The effects of these exports on seawater chemistry are profound yet complicated to study. This study presents the latest development of assessing lateral DIC and Alk fluxes from tidal marshes and examining their effects on seawater chemistry and coastal carbon budgets. The study evaluates different approaches to quantify these exports in order to obtain insights on the best and efficient way to capture the dynamics of such exports. A state-of-the-art DIC sensor, Channelized Optical System (CHANOS), was deployed to establish the true DIC fluxes. They are compared to the fluxes derived from empirical modeling and traditional bottle measurements. Salt marshes can acidify and alkalize tidal water by injecting CO2 (DIC) and Alk over a same tidal cycle. However, their generation is decoupled as a result of deferential effects of aerobic and anaerobic respirations. This creates complex scenarios of large swings of seawater chemistry and buffering capacity in tidal water over tidal and seasonal cycles. Marsh exports of DIC and Alk may have complex implications for the future, more acidified ocean. The latest estimates of marsh DIC and Alk exports suggest they are a major term in the marsh carbon budget and can be translated into one of the primary components in the coastal carbon cycle.

Programmed cell death in the marine cyanobacterium Trichodesmium mediates carbon and nitrogen export

PubMed Central

Bar-Zeev, Edo; Avishay, Itamar; Bidle, Kay D; Berman-Frank, Ilana

2013-01-01

The extent of carbon (C) and nitrogen (N) export to the deep ocean depends upon the efficacy of the biological pump that transports primary production to depth, thereby preventing its recycling in the upper photic zone. The dinitrogen-fixing (diazotrophic) Trichodesmium spp. contributes significantly to oceanic C and N cycling by forming extensive blooms in nutrient-poor tropical and subtropical regions. These massive blooms generally collapse several days after forming, but the cellular mechanism responsible, along with the magnitude of associated C and N export processes, are as yet unknown. Here, we used a custom-made, 2-m high water column to simulate a natural bloom and to specifically test and quantify whether the programmed cell death (PCD) of Trichodesmium mechanistically regulates increased vertical flux of C and N. Our findings demonstrate that extremely rapid development and abrupt, PCD-induced demise (within 2–3 days) of Trichodesmium blooms lead to greatly elevated excretions of transparent exopolymers and a massive downward pulse of particulate organic matter. Our results mechanistically link autocatalytic PCD and bloom collapse to quantitative C and N export fluxes, suggesting that PCD may have an impact on the biological pump efficiency in the oceans. PMID:23887173

76 FR 49735 - Citric Acid and Certain Citrate Salts From the People's Republic of China: Partial Rescission of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-11

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-938] Citric Acid and Certain... citric acid and certain citrate salts (``citric acid'') from the People's Republic of China (``PRC...., Ltd. (``Xinghua''), a producer and exporter of citric acid, timely requested that the Department...

Environmental impact of irrigation in la violada district (Spain): I. Salt export patterns.

PubMed

Isidoro, D; Quílez, D; Aragüés, R

2006-01-01

Salt loading in irrigation return flows contributes to the salinization of the receiving water bodies, particularly when originated in salt-affected areas as frequently found in the middle Ebro River basin (Spain). We determined the salt loading in La Violada Gully from the total dissolved solids (TDS) and flows (Q) during the 1995 to 1998 hydrological years. Since this gully collects flows from various sources, an end-member mixing analysis (EMMA) was performed to quantify the drainage flow from La Violada Irrigation District (VID). Three flow components were identified in La Violada Gully: drainage waters from VID (Qd); tail-waters from irrigation ditches, spill-over, and seepage from the Monegros Canal (Qo); and ground water inflows (Qg) originating in the dryland watershed. Gypsum in the soils of VID was the main source for salts in La Violada Gully (flow-weighted mean TDS=1720 mg L-1, dominated by sulfate and calcium). The contribution of Qg to the total gully flow during the 1996 irrigation season was low (6.5% of the total flow). The 1995 to 1998 annual salt load average in La Violada Gully was 78 628 Mg, 71% of which was exported during the irrigation season. The 1995 to 1998 irrigation season salt load average in Qd was 43 015 Mg (77% of the total load). Thus, irrigated agriculture in VID was the main source of salt loading in this gully, with a yield of 11.1 Mg of salts per hectare of irrigated land for the irrigation season. Efficient irrigation systems and irrigation management practices that reduce Qd are key factors for controlling off-site salt pollution of these gypsum-rich irrigated areas.

How NaCl raises blood pressure: a new paradigm for the pathogenesis of salt-dependent hypertension

PubMed Central

Leenen, Frans H. H.; Chen, Ling; Golovina, Vera A.; Hamlyn, John M.; Pallone, Thomas L.; Van Huysse, James W.; Zhang, Jin; Wier, W. Gil

2012-01-01

Excess dietary salt is a major cause of hypertension. Nevertheless, the specific mechanisms by which salt increases arterial constriction and peripheral vascular resistance, and thereby raises blood pressure (BP), are poorly understood. Here we summarize recent evidence that defines specific molecular links between Na+ and the elevated vascular resistance that directly produces high BP. In this new paradigm, high dietary salt raises cerebrospinal fluid [Na+]. This leads, via the Na+-sensing circumventricular organs of the brain, to increased sympathetic nerve activity (SNA), a major trigger of vasoconstriction. Plasma levels of endogenous ouabain (EO), the Na+ pump ligand, also become elevated. Remarkably, high cerebrospinal fluid [Na+]-evoked, locally secreted (hypothalamic) EO participates in a pathway that mediates the sustained increase in SNA. This hypothalamic signaling chain includes aldosterone, epithelial Na+ channels, EO, ouabain-sensitive α2 Na+ pumps, and angiotensin II (ANG II). The EO increases (e.g.) hypothalamic ANG-II type-1 receptor and NADPH oxidase and decreases neuronal nitric oxide synthase protein expression. The aldosterone-epithelial Na+ channel-EO-α2 Na+ pump-ANG-II pathway modulates the activity of brain cardiovascular control centers that regulate the BP set point and induce sustained changes in SNA. In the periphery, the EO secreted by the adrenal cortex directly enhances vasoconstriction via an EO-α2 Na+ pump-Na+/Ca2+ exchanger-Ca2+ signaling pathway. Circulating EO also activates an EO-α2 Na+ pump-Src kinase signaling cascade. This increases the expression of the Na+/Ca2+ exchanger-transient receptor potential cation channel Ca2+ signaling pathway in arterial smooth muscle but decreases the expression of endothelial vasodilator mechanisms. Additionally, EO is a growth factor and may directly participate in the arterial structural remodeling and lumen narrowing that is frequently observed in established hypertension. These several central and peripheral mechanisms are coordinated, in part by EO, to effect and maintain the salt-induced elevation of BP. PMID:22058154

Quantification of the lithogenic carbon pump following a dust deposition event

NASA Astrophysics Data System (ADS)

Bressac, M.; Guieu, C.; Doxaran, D.; Bourrin, F.; Desboeufs, K.; Leblond, N.; Ridame, C.

2013-08-01

Lithogenic particles, such as desert dust, have been postulated to influence particulate organic carbon (POC) export to the deep ocean by acting as mineral ballasts. However, an accurate understanding and quantification of the POC-dust association that occurs within the upper ocean is required in order to affine the "ballast hypothesis". In the framework of the DUNE project, two artificial seedings were performed seven days apart within large mesocosms. A suite of optical and biogeochemical measurements were used to quantify surface POC export following simulated dust events within a low-nutrient low-chlorophyll ecosystem. The two successive seedings led to a 2.3-6.7 fold higher POC flux as compared to the POC flux observed in controlled mesocosms. A simple linear regression analysis revealed that the lithogenic fluxes explained more than 85% of the variance in POC fluxes. At the scale of a dust deposition event, we estimated that 42-50% of POC fluxes were strictly associated with lithogenic particles through an aggregation process. Lithogenic ballasting also likely impacted the remaining POC fraction which resulted from the fertilization effect. The observations support the "ballast hypothesis" and provide a quantitative estimation of the surface POC export abiotically triggered by dust deposition. In this work, we demonstrate that the strength of such a "lithogenic carbon pump" depends on the biogeochemical conditions of the water column at the time of deposition. Based on these observations, we suggest that this "lithogenic carbon pump" could represent a major component of the biological pump in oceanic areas subjected to intense atmospheric forcing.

[Microbiological rationale for using whey on salting salmon caviar].

PubMed

Kim, I N; Shtan'ko, T I

2011-01-01

The paper provides a rationale for the use of whey to salt salmon fishes instead of traditional preservatives, including those exported from low industrial potential countries, which do not undergo comprehensive sanitary and hygienic tests. On the basis of the performed studies, the authors recommend to use whey to salt salmon caviar, which ensures the ecological purity of the product containing the minimum amount of preservatives and other substances that fail to affect its organoleptic properties.

Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants

PubMed Central

Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

2016-01-01

The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na+/H+) antiporter that transports Na+ into the vacuole and exports H+ into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na+/H+ antiporter that exports Na+ to the extracellular space and imports H+ into the plant cell. Plants rely on these enzymes either to keep Na+ out of the cell or to sequester Na+ into vacuoles to avoid the toxic level of Na+ in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. PMID:26985021

Intertidal salt marshes as an important source of inorganic carbon to the coastal ocean

USGS Publications Warehouse

Wang, Zhaohui Aleck; Kroeger, Kevin D.; Ganju, Neil K.; Gonneea, Meagan; Chu, Sophie N.

2016-01-01

Dynamic tidal export of dissolved inorganic carbon (DIC) to the coastal ocean from highly productive intertidal marshes and its effects on seawater carbonate chemistry are thoroughly evaluated. The study uses a comprehensive approach by combining tidal water sampling of CO2parameters across seasons, continuous in situ measurements of biogeochemically-relevant parameters and water fluxes, with high-resolution modeling in an intertidal salt marsh of the U.S. northeast region. Salt marshes can acidify and alkalize tidal water by injecting CO2 (DIC) and total alkalinity (TA). DIC and TA generation may also be decoupled due to differential effects of marsh aerobic and anaerobic respiration on DIC and TA. As marsh DIC is added to tidal water, the buffering capacity first decreases to a minimum and then increases quickly. Large additions of marsh DIC can result in higher buffering capacity in ebbing tide than incoming tide. Alkalization of tidal water, which mostly occurs in the summer due to anaerobic respiration, can further modify buffering capacity. Marsh exports of DIC and alkalinity may have complex implications for the future, more acidified ocean. Marsh DIC export exhibits high variability over tidal and seasonal cycles, which is modulated by both marsh DIC generation and by water fluxes. The marsh DIC export of 414 g C m−2 yr−1, based on high-resolution measurements and modeling, is more than twice the previous estimates. It is a major term in the marsh carbon budget and translates to one of the largest carbon fluxes along the U.S. East Coast.

BLENDING ANALYSIS FOR RADIOACTIVE SALT WASTE PROCESSING FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, S.

2012-05-10

Savannah River National Laboratory (SRNL) evaluated methods to mix and blend the contents of the blend tanks to ensure the contents are properly blended before they are transferred from the blend tank such as Tank 21 and Tank 24 to the Salt Waste Processing Facility (SWPF) feed tank. The tank contents consist of three forms: dissolved salt solution, other waste salt solutions, and sludge containing settled solids. This paper focuses on developing the computational model and estimating the operation time of submersible slurry pump when the tank contents are adequately blended prior to their transfer to the SWPF facility. Amore » three-dimensional computational fluid dynamics approach was taken by using the full scale configuration of SRS Type-IV tank, Tank 21H. Major solid obstructions such as the tank wall boundary, the transfer pump column, and three slurry pump housings including one active and two inactive pumps were included in the mixing performance model. Basic flow pattern results predicted by the computational model were benchmarked against the SRNL test results and literature data. Tank 21 is a waste tank that is used to prepare batches of salt feed for SWPF. The salt feed must be a homogeneous solution satisfying the acceptance criterion of the solids entrainment during transfer operation. The work scope described here consists of two modeling areas. They are the steady state flow pattern calculations before the addition of acid solution for tank blending operation and the transient mixing analysis during miscible liquid blending operation. The transient blending calculations were performed by using the 95% homogeneity criterion for the entire liquid domain of the tank. The initial conditions for the entire modeling domain were based on the steady-state flow pattern results with zero second phase concentration. The performance model was also benchmarked against the SRNL test results and literature data.« less

Study Orientation Ply of Fiberglass on Blade Salt Water Pump Windmill using Abaqus

NASA Astrophysics Data System (ADS)

Badruzzaman, B.; Sifa, A.

2018-02-01

Windmill is one tool to generate energy from wind energy is converted into energy motion, salt production process still using traditional process by utilizing windmill to move sea water to salt field With a windmill driven water system, a horizontal axis type windmill with an average windmill height of 3-4 m, with a potential wind speed of 5-9 m / s, the amount of blade used for salt water pumps as much as 4 blades, one of the main factor of the windmill component is a blade, blade designed for the needs of a salt water pump by using fiberglass material. On layer orientation 0°,30°,45°,60° and 90° with layer number 10 and layer thickness 2 mm, the purpose of this study was to determine the strength of fiberglass that was influenced by the orientation of the layer, and to determine the orientation of fiberglass layer before making. This method used Finite Element Analysis method using ABAQUS, with homogenous and heterogeneous layer parameters. The simulation result shows the difference in von misses value at an angle of 0°, 30°, 45°,60° homogeneous value is greater than heterogeneous value, whereas in orientation 90 heterogeneous values have value 1,689e9 Pa, greater than homogenous 90 orientation value of 1,296e9 Pa.

All0809/8/7 is a DevBCA-like ABC-type efflux pump required for diazotrophic growth in Anabaena sp. PCC 7120.

PubMed

Staron, Peter; Maldener, Iris

2012-10-01

Efflux pumps export a wide variety of proteinaceous and non-proteinaceous substrates across the Gram-negative cell wall. For the filamentous cyanobacterium Anabaena sp. strain PCC 7120, the ATP-driven glycolipid efflux pump DevBCA-TolC has been shown to be crucial for the differentiation of N(2)-fixing heterocysts from photosynthetically active vegetative cells. In this study, a homologous system was described. All0809/8/7-TolC form a typical ATP-driven efflux pump as shown by surface plasmon resonance. This putative exporter is also involved in diazotrophic growth of Anabaena sp. PCC 7120. A mutant in all0809 encoding the periplasmic membrane fusion protein of the pump was not able to grow without combined nitrogen. Although heterocysts of this mutant were not distinguishable from those of the wild-type in light and electron micrographs, they were impaired in providing the microoxic environment necessary for N(2) fixation. RT-PCR of all0809 transcripts and localization studies on All0807-GFP revealed that All0809/8/7 was initially downregulated during heterocyst maturation and upregulated at later stages of heterocyst formation in all cells of the filament. A substrate of the efflux pump could not be identified in ATP hydrolysis assays. We discuss a role for All0809/8/7-TolC in maintaining the continuous periplasm and how this would be of special importance for heterocyst differentiation.

27. EXTENSION OF SURGE CHAMBER AND AIR PIPES TO PRESSURE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

27. EXTENSION OF SURGE CHAMBER AND AIR PIPES TO PRESSURE LINE, HIGHLINE PUMPING PLANT. December 11, 1920 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

A New Desalination Pump Helps Define the pH of Ocean Worlds

NASA Astrophysics Data System (ADS)

Levi, A.; Sasselov, D.

2018-04-01

We study ocean exoplanets, for which the global surface ocean is separated from the rocky interior by a high-pressure ice mantle. We describe a mechanism that can pump salts out of the ocean, resulting in oceans of very low salinity. Here we focus on the H2O–NaCl system, though we discuss the application of this pump to other salts as well. We find our ocean worlds to be acidic, with a pH in the range of 2–4. We discuss and compare between the conditions found within our studied oceans and the conditions in which polyextremophiles were discovered. This work focuses on exoplanets in the super-Earth mass range (∼2 M ⊕), with water composing at least a few percent of their mass. However, the principle of the desalination pump might extend beyond this mass range.

Influence of diatom diversity on the ocean biological carbon pump

NASA Astrophysics Data System (ADS)

Tréguer, Paul; Bowler, Chris; Moriceau, Brivaela; Dutkiewicz, Stephanie; Gehlen, Marion; Aumont, Olivier; Bittner, Lucie; Dugdale, Richard; Finkel, Zoe; Iudicone, Daniele; Jahn, Oliver; Guidi, Lionel; Lasbleiz, Marine; Leblanc, Karine; Levy, Marina; Pondaven, Philippe

2018-01-01

Diatoms sustain the marine food web and contribute to the export of carbon from the surface ocean to depth. They account for about 40% of marine primary productivity and particulate carbon exported to depth as part of the biological pump. Diatoms have long been known to be abundant in turbulent, nutrient-rich waters, but observations and simulations indicate that they are dominant also in meso- and submesoscale structures such as fronts and filaments, and in the deep chlorophyll maximum. Diatoms vary widely in size, morphology and elemental composition, all of which control the quality, quantity and sinking speed of biogenic matter to depth. In particular, their silica shells provide ballast to marine snow and faecal pellets, and can help transport carbon to both the mesopelagic layer and deep ocean. Herein we show that the extent to which diatoms contribute to the export of carbon varies by diatom type, with carbon transfer modulated by the Si/C ratio of diatom cells, the thickness of the shells and their life strategies; for instance, the tendency to form aggregates or resting spores. Model simulations project a decline in the contribution of diatoms to primary production everywhere outside of the Southern Ocean. We argue that we need to understand changes in diatom diversity, life cycle and plankton interactions in a warmer and more acidic ocean in much more detail to fully assess any changes in their contribution to the biological pump.

Estimating the Change of Groundwater Salinization in the Central North China Plain for Sustainable Groundwater Utilization

NASA Astrophysics Data System (ADS)

Zhan, Y.; He, X.; Zheng, C.; Guo, Z.

2017-12-01

Due to the growing demand of food supplies and limited freshwater resources, North China Plain (NCP) is highly dependent on the groundwater resources. Groundwater overdraft has made NCP a closed hydrologic basin, where the connection between surface and groundwater has been cut off, which can lead to salt accumulation in the groundwater system. Thus it is imperative to investigate the overall salt balance in the region for sustainable utilization of groundwater resources, as well as to better understand the salt accumulating processes caused by groundwater pumping and return flow. The central plain of NCP (excluding the piedmont plain and coastal plain) is selected in the present study, where the groundwater salt content is mainly controlled by precipitation, irrigation, groundwater pumping and rock-water interaction in vertical direction; therefore, a conceptual 1-D mixing model is developed for salt balance calculation, where the salt content is expressed by the concentration of Total Dissolved Solid (TDS) in groundwater. Geological structures and regional water balance data are obtained from numerical groundwater models previously developed in the area. The simulation starts in year 1900 with a 50-year time step and groundwater vertical flow velocity starting with 2 m/y. TDS concentration is then calculated through salt input and output in each layer, with consideration of soil salt accumulation, change of precipitation, rock-water interaction etc. The results suggest that in a closed hydrologic basin, groundwater pumping and return flow will gradually increase salt content in the groundwater body from upper layers to lower layers resulting from the flushing of salt accumulated in the top soil layer. After two time steps, the model is able to reproduce the observed TDS concentration in present time with reasonable accuracy; and after six time steps, which correspond to 300 years, the whole central plain of NCP will be under the influence of high salinity, which is around 2000 mg/L of TDS. The study also suggests that in order to predict the future change of salt content in groundwater in NCP more accurately, the mechanisms of how salinity accumulates in the surface soil is the most critical factor, which requires further research.

Salt Acclimation of Cyanobacteria and Their Application in Biotechnology

PubMed Central

Pade, Nadin; Hagemann, Martin

2014-01-01

The long evolutionary history and photo-autotrophic lifestyle of cyanobacteria has allowed them to colonize almost all photic habitats on Earth, including environments with high or fluctuating salinity. Their basal salt acclimation strategy includes two principal reactions, the active export of ions and the accumulation of compatible solutes. Cyanobacterial salt acclimation has been characterized in much detail using selected model cyanobacteria, but their salt sensing and regulatory mechanisms are less well understood. Here, we briefly review recent advances in the identification of salt acclimation processes and the essential genes/proteins involved in acclimation to high salt. This knowledge is of increasing importance because the necessary mass cultivation of cyanobacteria for future use in biotechnology will be performed in sea water. In addition, cyanobacterial salt resistance genes also can be applied to improve the salt tolerance of salt sensitive organisms, such as crop plants. PMID:25551682

Quantification of the lithogenic carbon pump following a simulated dust-deposition event in large mesocosms

NASA Astrophysics Data System (ADS)

Bressac, M.; Guieu, C.; Doxaran, D.; Bourrin, F.; Desboeufs, K.; Leblond, N.; Ridame, C.

2014-02-01

Lithogenic particles, such as desert dust, have been postulated to influence particulate organic carbon (POC) export to the deep ocean by acting as mineral ballasts. However, an accurate understanding and quantification of the POC-dust association that occurs within the upper ocean is required in order to refine the "ballast hypothesis". In the framework of the DUNE (a DUst experiment in a low-Nutrient, low-chlorophyll Ecosystem) project, two artificial seedings were performed seven days apart within large mesocosms. A suite of optical and biogeochemical measurements were used to quantify surface POC export following simulated dust events within a low-nutrient, low-chlorophyll ecosystem. The two successive seedings led to a 2.3-6.7-fold higher POC flux than the POC flux observed in controlled mesocosms. A simple linear regression analysis revealed that the lithogenic fluxes explained more than 85% of the variance in POC fluxes. On the scale of a dust-deposition event, we estimated that 42-50% of POC fluxes were strictly associated with lithogenic particles (through aggregation and most probably sorption processes). Lithogenic ballasting also likely impacted the remaining POC fraction which resulted from the fertilization effect. The observations support the "ballast hypothesis" and provide a quantitative estimation of the surface POC export abiotically triggered by dust deposition. In this work, we demonstrate that the strength of such a "lithogenic carbon pump" depends on the biogeochemical conditions of the water column at the time of deposition. Based on these observations, we suggest that this lithogenic carbon pump could represent a major component of the biological pump in oceanic areas subjected to intense atmospheric forcing.

Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants.

PubMed

Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

2016-05-01

The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na(+)/H(+)) antiporter that transports Na(+) into the vacuole and exports H(+) into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na(+)/H(+) antiporter that exports Na(+) to the extracellular space and imports H(+) into the plant cell. Plants rely on these enzymes either to keep Na(+) out of the cell or to sequester Na(+) into vacuoles to avoid the toxic level of Na(+) in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

76 FR 22698 - Arizona Independent Power, Inc.; Notice of Preliminary Permit Application Accepted for Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-22

...), proposing to study the feasibility of the Verde Pumped Storage Project (project) to be located within the... Company or Salt River Project. The estimated annual generation of the Verde Pumped Storage Project would...

A High Resolution Tampa Bay Hydrodynamic Model and its Application to Residence Time Estimation and Salt Balance Diagnosis

NASA Astrophysics Data System (ADS)

Zheng, L.; Weisberg, R. H.

2016-02-01

A 3D, numerical circulation model, with high resolution (20 m) at important mass conveyances (inlets and rivers etc.), is developed to estimate the bulk residence time and diagnose the salt balances and salt fluxes for Tampa Bay estuary. These analyses are justified via quantitative comparisons between the simulation and observations of sea level, velocity and salinity. The non-tidal circulation is the primary agent for the flushing of Tampa Bay. Tides alone have a minor effect. Exceptions pertain to within a tidal excursion from the bay mouth and regions with multiple inlets where different tide phases aid in flushing. The fully 3D salt flux divergences (SFD) and fluxes vary spatially throughout the estuary. On experimental duration (three month) average, the total advective SFD is balanced primarily by the vertical diffusive SFD, except near the bottom of the channel where the horizontal diffusive SFD is also important. Instantaneously, the local rate of salinity change is controlled primarily by the advective SFD, with a secondary contribution by the vertical diffusive SFD everywhere and the horizontal diffusive SFD near the channel bottom. After decomposing the advective salt fluxes and their divergences into mean quantity and tidal pumping, the horizontal and vertical advective SFDs by the mean quantities are large and counterbalance, with their sum being a small but significant residual. The horizontal and vertical advective SFDs by tidal pumping are relatively small (when compared with the mean quantities) and counterbalance; but, when summed, their residual is comparable in magnitude to that by the mean quantities. So whereas the salt fluxes by tidal pumping are secondary importance to the salt fluxes by the mean quantities, their total flux divergences are of comparable importance. The salt flux 3D components vary along the Tampa Bay axis, and these findings may be typical of coastal plain estuaries given their geometrical complexities.

Preliminary study on Emodin alleviating alpha-naphthylisothiocyanate-induced intrahepatic cholestasis by regulation of liver farnesoid X receptor pathway.

PubMed

Ding, Yan; Xiong, Xiao-Li; Zhou, Li-Shan; Yan, Su-Qi; Qin, Huan; Li, Hua-Rong; Zhang, Ling-Ling; Chen, Peng; Yao, Cong; Jiang, Zhi-Xia; Zhao, Lei

2016-12-01

The aim of this study is to investigate Emodin on alleviating intrahepatic cholestasis by regulation of liver farnesoid X receptor (FXR) pathway. Cell and animal models of intrahepatic cholestatis were established. Biochemical tests and histomorphology were performed. The messenger RNA (mRNA) and protein expression of FXR, small heterodimer partner (SHP), uridine diphosphate glucuronosyltransferase 2 family polypeptide B4 (UGT2B4), and bile salt export pump (BSEP) was detected. As a result, compared with the model group, the serum levels of biochemical test were significantly lower in the Emodin group (P <0.01). The histopathological changes were remitted significantly by Emodin treatment. In the model group, the mRNA and protein expression of FXR, SHP, UGT2B4, and BSEP was significantly lower than in the normal group in cell models (P <0.05). With Emodin intervention, the expression of FXR, SHP, UGT2B4, and BSEP was notably increased (P <0.05). In conclusion, Emodin plays a protective role in intrahepatic cholestasis by promoting FXR signal pathways. © The Author(s) 2016.

Global assessment of ocean carbon export by combining satellite observations and food-web models

NASA Astrophysics Data System (ADS)

Siegel, D. A.; Buesseler, K. O.; Doney, S. C.; Sailley, S. F.; Behrenfeld, M. J.; Boyd, P. W.

2014-03-01

The export of organic carbon from the surface ocean by sinking particles is an important, yet highly uncertain, component of the global carbon cycle. Here we introduce a mechanistic assessment of the global ocean carbon export using satellite observations, including determinations of net primary production and the slope of the particle size spectrum, to drive a food-web model that estimates the production of sinking zooplankton feces and algal aggregates comprising the sinking particle flux at the base of the euphotic zone. The synthesis of observations and models reveals fundamentally different and ecologically consistent regional-scale patterns in export and export efficiency not found in previous global carbon export assessments. The model reproduces regional-scale particle export field observations and predicts a climatological mean global carbon export from the euphotic zone of 6 Pg C yr-1. Global export estimates show small variation (typically < 10%) to factor of 2 changes in model parameter values. The model is also robust to the choices of the satellite data products used and enables interannual changes to be quantified. The present synthesis of observations and models provides a path for quantifying the ocean's biological pump.

16. VIEW OF HIGHLINE CANAL PIPELINE OUTLET, SHOWING THE OUTLET, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. VIEW OF HIGHLINE CANAL PIPELINE OUTLET, SHOWING THE OUTLET, A GROUNDWATER PUMP (LEFT), AND THE SOUTH BRANCH OF THE CANAL (FOREGROUND), August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

Measured flow and tracer-dye data for spring 1996 and 1997 for the south Sacramento-San Joaquin Delta, California

USGS Publications Warehouse

Oltmann, Richard N.

1999-01-01

During the spring of years when the flow of the San Joaquin River is less than 7,000 cubic feet per second (ft3/s) a temporary rock barrier is installed by the California Department of Water Resources (DWR) at the head of Old River (HOR) in the south Sacramento-San Joaquin Delta to prevent out migrating salmon in the San Joaquin River from entering Old River and being drawn to the State and federal pumping facilities (Figure 1). The export rate of the pumping facilities also is reduced during these migration periods to minimize the draw of fish to the export facilities through the other channels connected to the San Joaquin River north of the HOR such as Turner Cut, Columbia Cut, and Middle River.

The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

NASA Astrophysics Data System (ADS)

Jin, X.; Gruber, N.; Frenzel, H.; Doney, S. C.; McWilliams, J. C.

2008-03-01

Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical/biogeochemical/ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC) removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, integrated over 10 years, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production and export. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability) tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

Signaling mechanisms that link salt retention to hypertension: endogenous ouabain, the Na(+) pump, the Na(+)/Ca(2+) exchanger and TRPC proteins.

PubMed

Blaustein, Mordecai P; Hamlyn, John M

2010-12-01

Salt retention as a result of chronic, excessive dietary salt intake, is widely accepted as one of the most common causes of hypertension. In a small minority of cases, enhanced Na(+) reabsorption by the kidney can be traced to specific genetic defects of salt transport, or pathological conditions of the kidney, adrenal cortex, or pituitary. Far more frequently, however, salt retention may be the result of minor renal injury or small genetic variation in renal salt transport mechanisms. How salt retention actually leads to the increase in peripheral vascular resistance (the hallmark of hypertension) and the elevation of blood pressure remains an enigma. Here we review the evidence that endogenous ouabain (an adrenocortical hormone), arterial smooth muscle α2 Na(+) pumps, type-1 Na/Ca exchangers, and receptor- and store-operated Ca(2+) channels play key roles in the pathway that links salt to hypertension. We discuss cardenolide structure-function relationships in an effort to understand why prolonged administration of ouabain, but not digoxin, induces hypertension, and why digoxin is actually anti-hypertensive. Finally, we summarize recent observations which indicate that ouabain upregulates arterial myocyte Ca(2+) signaling mechanisms that promote vasoconstriction, while simultaneously downregulating endothelial vasodilator mechanisms. In sum, the reports reviewed here provide novel insight into the molecular mechanisms by which salt retention leads to hypertension. Copyright © 2010 Elsevier B.V. All rights reserved.

Influence of a Decaying Cyclonic Eddy on Biogenic Silica and Particulate Organic Carbon in the Tropical South China Sea Based on 234Th-238U Disequilibrium.

PubMed

Yang, Weifeng; Chen, Min; Zheng, Minfang; He, Zhigang; Zhang, Xinxing; Qiu, Yusheng; Xu, Wangbin; Ma, Lili; Lin, Zhiyu; Hu, Wangjiang; Zeng, Jian

2015-01-01

Eddies play a critical role in regulating the biological pump by pumping new nutrients to the euphotic zone. However, the effects of cyclonic eddies on particle export are not well understood. Here, biogenic silica (BSi) and particulate organic carbon (POC) exports were examined inside and outside a decaying cyclonic eddy using 234Th-238U disequilibria in the tropical South China Sea. For the eddy and outside stations, the average concentrations of BSi in the euphotic zone were 0.17±0.09 μmol L-1 (mean±sd, n = 20) and 0.21±0.06 μmol L-1 (n = 34). The POC concentrations were 1.42±0.56 μmol L-1 (n = 34) and 1.30±0.46 μmol L-1 (n = 51). Both BSi and POC abundances did not show change at the 95% confidence level. Based on the 234Th-238U model, BSi export fluxes in the eddy averaged 0.18±0.15 mmol Si m-2 d-1, which was comparable with the 0.40±0.20 mmol Si m-2 d-1 outside the eddy. Similarly, the average POC export fluxes were 1.5±1.4 mmol C m-2 d-1 and 1.9±1.3 mmol C m-2 d-1 for the eddy and outside stations. From these results we concluded that cyclonic eddies in their decaying phase have little effect on the abundance and export of biogenic particles.

Influence of a Decaying Cyclonic Eddy on Biogenic Silica and Particulate Organic Carbon in the Tropical South China Sea Based on 234Th-238U Disequilibrium

PubMed Central

Yang, Weifeng; Chen, Min; Zheng, Minfang; He, Zhigang; Zhang, Xinxing; Qiu, Yusheng; Xu, Wangbin; Ma, Lili; Lin, Zhiyu; Hu, Wangjiang; Zeng, Jian

2015-01-01

Eddies play a critical role in regulating the biological pump by pumping new nutrients to the euphotic zone. However, the effects of cyclonic eddies on particle export are not well understood. Here, biogenic silica (BSi) and particulate organic carbon (POC) exports were examined inside and outside a decaying cyclonic eddy using 234Th-238U disequilibria in the tropical South China Sea. For the eddy and outside stations, the average concentrations of BSi in the euphotic zone were 0.17±0.09 μmol L-1 (mean±sd, n = 20) and 0.21±0.06 μmol L-1 (n = 34). The POC concentrations were 1.42±0.56 μmol L-1 (n = 34) and 1.30±0.46 μmol L-1 (n = 51). Both BSi and POC abundances did not show change at the 95% confidence level. Based on the 234Th-238U model, BSi export fluxes in the eddy averaged 0.18±0.15 mmol Si m-2 d-1, which was comparable with the 0.40±0.20 mmol Si m-2 d-1 outside the eddy. Similarly, the average POC export fluxes were 1.5±1.4 mmol C m-2 d-1 and 1.9±1.3 mmol C m-2 d-1 for the eddy and outside stations. From these results we concluded that cyclonic eddies in their decaying phase have little effect on the abundance and export of biogenic particles. PMID:26317555

Geohydrology of the northern Louisiana salt-dome basin pertinent to the storage of radioactive wastes; a progress report

USGS Publications Warehouse

Hosman, R.L.

1978-01-01

Salt domes in northern Louisiana are being considered as possible storage sites for nuclear wastes. The domes are in an area that received regional sedimentation through early Tertiary (Eocene) time with lesser amounts of Quaternary deposits. The Cretaceous-Tertiary accumulation is a few thousand feet thick; the major sands are regional aquifers that extend far beyond the boundaries of the salt-dome basin. Because of multiple aquifers, structural deformation, and variations in the hydraulic characteristics of cap rock, the ground-water hydrology around a salt dome may be highly complex. The Sparta Sand is the most productive and heavily used regional aquifer. It is either penetrated by or overlies most of the domes. A fluid entering the Sparta flow system would move toward one of the pumping centers, all at or near municipalities that pump from the Sparta. Movement could be toward surface drainage where local geologic and hydrologic conditions permit leakage to the surface or to a surficial aquifer. (Woodard-USGS)

Ocean Biological Pump Sensitivities and Implications for Climate Change Impacts

NASA Technical Reports Server (NTRS)

Romanou, Anastasia

2013-01-01

The ocean is one of the principal reservoirs of CO2, a greenhouse gas, and therefore plays a crucial role in regulating Earth's climate. Currently, the ocean sequesters about a third of anthropogenic CO2 emissions, mitigating the human impact on climate. At the same time, the deeper ocean represents the largest carbon pool in the Earth System and processes that describe the transfer of carbon from the surface of the ocean to depth are intimately linked to the effectiveness of carbon sequestration.The ocean biological pump (OBP), which involves several biogeochemical processes, is a major pathway for transfer of carbon from the surface mixed layer into the ocean interior. About 75 of the carbon vertical gradient is due to the carbon pump with only 25 attributed to the solubility pump. However, the relative importance and role of the two pumps is poorly constrained. OBP is further divided to the organic carbon pump (soft tissue pump) and the carbonate pump, with the former exporting about 10 times more carbon than the latter through processes like remineralization.Major uncertainties about OBP, and hence in the carbon uptake and sequestration, stem from uncertainties in processes involved in OBP such as particulate organicinorganic carbon sinkingsettling, remineralization, microbial degradation of DOC and uptakegrowth rate changes of the ocean biology. The deep ocean is a major sink of atmospheric CO2 in scales of hundreds to thousands of years, but how the export efficiency (i.e. the fraction of total carbon fixation at the surface that is transported at depth) is affected by climate change remains largely undetermined. These processes affect the ocean chemistry (alkalinity, pH, DIC, particulate and dissolved organic carbon) as well as the ecology (biodiversity, functional groups and their interactions) in the ocean. It is important to have a rigorous, quantitative understanding of the uncertainties involved in the observational measurements, the models and the projections of future changes.

Is ABA involved in tolerance responses to salinity by affecting cytoplasm ion homeostasis in rice cell lines?

PubMed

Pons, Raül; Cornejo, María Jesús; Sanz, Amparo

2013-01-01

The ability of plant cells to maintain cytoplasm ion homeostasis under saline stress is among the main mechanisms involved in salt tolerance. To cope with excess Na(+), cells extrude it from the cytoplasm, which requires expenditure of metabolic energy, provided by H(+) gradients generated by membrane-bound H(+)-pumps. ABA is well-known to be involved in physiological processes elicited or enhanced by stresses causing cell dehydration. In this work we studied the possible implication of this plant hormone in the control of salt-induced cellular mechanisms conducting to Na(+) extrusion from the cytoplasm. We used rice (Oryza sativa L.) cell lines selected for their different tolerance to salinity to measure the response to ABA of H(+)-pumps and Na(+)/H(+)-antiporters associated to the plasma membrane and the tonoplast. Our results show that ABA generally enhances H(+)-pumping under salt stress but not under control conditions. This effect occurs to a higher extent across the tonoplast in the more tolerant lines (L-T). Na(+)/H(+) antiport activity is practically undetectable in calli under control conditions, pre-treated or not with ABA, but shows a strong activation under salinity across the tonoplast, particularly in L-T lines (cv Bahia) and also across de plasma membrane in cv Bomba. In these lines, prior treatments with ABA tend to reduce the NaCl enhanced activity of both antiporters. Overall, under saline conditions ABA seems to affect synergistically H(+) pumping and antagonistically Na(+) extrusion. A complex network of positive and negative regulatory signals seems involved in restoring ion cell homeostasis under salt stress. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Role of eddy pumping in enhancing primary production in the ocean

NASA Technical Reports Server (NTRS)

Falkowski, Paul G.; Kolber, Zbigniew; Ziemann, David; Bienfang, Paul K.

1991-01-01

Eddy pumping is considered to explain the disparity between geochemical estimates and biological measurements of exported production. Episodic nutrient injections from the ocean into the photic zone can be generated by eddy pumping, which biological measurements cannot sample accurately. The enhancement of production is studied with respect to a cyclonic eddy in the subtropical Pacific. A pump-and-probe fluorimeter generates continuous vertical profiles of primary productivity from which the contributions of photochemical and nonphotochemical processes to fluorescence are derived. A significant correlation is observed between the fluorescence measurements and radiocarbon measurements. The results indicate that eddy pumping has an important effect on phytoplankton production and that this production is near the maximum relative specific growth rates. Based on the production enhancement observed in this case, eddy pumping increases total primary production by only 20 percent and does not account for all enhancement.

14. VIEW OF WESTERN CANAL AT THE SALT RIVER PROJECT'S ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. VIEW OF WESTERN CANAL AT THE SALT RIVER PROJECT'S KYRENE STEAM POWER PLANT, TEMPE. THE WESTERN CANAL BEGINS TO TURN NORTH AT THIS POINT, AND DIVERTS WATER TO THE HIGHLINE PUMP PLANT AND THE KYRENE LATERAL. THE KYRENE PLANT INLET (LEFT-CENTER) ALSO DIVERTS CANAL WATER FOR PLANT OPERATION AND COOLING. - Western Canal, South side of Salt River between Tempe, Phoenix & Mesa, Mesa, Maricopa County, AZ

Irrigation efficiency and quality of irrigation return flows in the Ebro River Basin: an overview.

PubMed

Causapé, J; Quílez, D; Aragüés, R

2006-06-01

The review analysis of twenty two irrigation efficiency (IE) studies carried out in the Ebro River Basin shows that IE is low (average IE)(avg)(= 53%) in surface-irrigated areas with high-permeable and shallow soils inadequate for this irrigation system, high (IE)(avg)(= 79%) in surface-irrigated areas with appropriate soils for this system, and very high (IE)(avg)(= 94%) in modern, automated and well managed sprinkler-irrigated areas. The unitary salt (total dissolved solids) and nitrate loads exported in the irrigation return flows (IRF) of seven districts vary, depending on soil salinity and on irrigation and N fertilization management, between 3-16 Mg salt/ha x year and 23-195 kg NO)(3) (-)-N/ha x year, respectively. The lower nitrate loads exported from high IE districts show that a proper irrigation design and management is a key factor to reduce off-site nitrogen pollution. Although high IE's also reduce off-site salt pollution, the presence of salts in the soil or subsoil may induce relatively high salt loads (>or=14 Mg/ha x year) even in high IE districts. Two important constrains identified in our revision were the short duration of most surveys and the lack of standards for conducting irrigation efficiency and mass balance studies at the irrigation district level. These limitations {emphasize the need for the establishment of a permanent and standardized network of drainage monitoring stations for the appropriate off-site pollution diagnosis and control of irrigated agriculture.

Section 7 reactor incident file general information from 1945

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1969-01-10

At 0308 on January 10, 1966, both B and C Reactors ``scrammed`` due to an electrical fault on Line C2-L8 caused by a raccoon coming in contact with the 13-8 KV line on top of transformer No. 2 at 182-B Building. Line C2-L8 relayed out at the 151-B Building. Details of the occurrence at 151-B are covered in the attachment. C-Reactor scrammed due to reduced voltage on the pressure monitor system. The reduction in voltage caused the auxiliary relays of the pressure monitor ground detector to open, de-energizing the end result relays PSR and PSRA. The safety circuit trip identificationmore » system displayed ``Pressure Monitor`` and ``Ground Detector.`` B-Reactor scrammed by a power failure signal from 190-B Building. The power failure relays for pump numbers 1 and 3 opened due to these pumps contributing power to the fault. The power failure relays at 190-B remained open long enough for the end result relays PF and PFA to open. Since these relays are timed delayed, 0.26 seconds, the power failure relays must have remained open at least that long. At the 190-B Building the steam turbines started due to the power failure relays for pump numbers 1 and 3 opening. The main process pumps remained stable and continued to supply normal flow to the reactor. Pumps were tripped from the line at 182-B and 183-B Buildings. The surge suppressors cycled normally and the turbine export pumps started as a result of low export line pressure. No power equipment was affected in C Area.« less

78 FR 65265 - Materials Technical Advisory Committee; Notice of Open Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

... BIS senior management and export control reform update. 3. Presentation from DuPont on the challenges... friendly. 4. Report of Composite Working Group. 5. Report of Biological and Pump/Valves Working Group. 6...

40 CFR 445.1 - General applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., waste piles, salt dome formations, salt bed formations, underground mines or caves as these terms are... ground water or wastewater from recovery pumping wells. (e) This part does not apply to discharges of... Treatment (CWT) facilities subject to 40 CFR part 437 so long as the CWT facility commingles the landfill...

Annual Cycles of Deep-ocean, Biogeochemical Export Fluxes and Biological Pump Processes in Subtropical and Subantarctic Waters, Southwest Pacific Ocean

NASA Astrophysics Data System (ADS)

Nodder, S.; Chiswell, S.; Northcote, L.

2016-02-01

One of the key aspects of the global carbon cycle is the efficiency and spatio-temporal variability of the biological pump. In this paper, the annual cycles of particle fluxes, derived from moored sediment trap data collected from 2000-12 in subtropical (STW) and subantarctic waters (SAW), east of New Zealand, are presented. These observations are the most comprehensive export flux time-series from temperate Southern Hemisphere latitudes to date. With high levels of variability, fluxes in SAW were markedly lower than in STW, reflecting the picophytoplankton-dominated communities in the iron-limited, high nutrient-low chlorophyll SAW. Austral spring chlorophyll blooms in surface STW were near-synchronous with elevated fluxes of bio-siliceous, carbonate and organic carbon-rich materials to the deep ocean, probably facilitated by diatom sedimentation. Lithogenic fluxes were also high in STW, compared to SAW, reflecting proximity to the New Zealand landmass. In contrast, the highest biogenic fluxes in SAW occurred in spring when surface chlorophyll concentrations were low, while highest annual chlorophyll concentrations were in summer with no associated flux increase. We hypothesize that the high spring export in SAW occurs from subsurface chlorophyll accumulations that are not evident from remote-sensing satellites. This material was also rich in biogenic silica, perhaps related to the preferential export of diatoms and other silica-producing organisms, such as silicoflagellates and radiolarians. Particle fluxes in STW are similar to that of other mesotrophic to oligotrophic waters ( 6-7 mgC m-2 d-1), whereas export from SAW is below global averages ( 3 mgC m-2 d-1), and is characterized by carbonate-dominated and prominent bio-siliceous deposition.

Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau

NASA Astrophysics Data System (ADS)

Rembauville, M.; Meilland, J.; Ziveri, P.; Schiebel, R.; Blain, S.; Salter, I.

2016-05-01

We report the contribution of planktic foraminifers and coccoliths to the particulate inorganic carbon (PIC) export fluxes collected over an annual cycle (October 2011/September 2012) on the central Kerguelen Plateau in the Antarctic Zone (AAZ) south of the Polar Front (PF). The seasonality of PIC flux was decoupled from surface chlorophyll a concentration and particulate organic carbon (POC) fluxes and was characterized by a late summer (February) maximum. This peak was concomitant with the highest satellite-derived sea surface PIC and corresponded to a Emiliania huxleyi coccoliths export event that accounted for 85% of the annual PIC export. The foraminifer contribution to the annual PIC flux was much lower (15%) and dominated by Turborotalita quinqueloba and Neogloboquadrina pachyderma. Foraminifer export fluxes were closely related to the surface chlorophyll a concentration, suggesting food availability as an important factor regulating the foraminifer's biomass. We compared size-normalized test weight (SNW) of the foraminifers with previously published SNW from the Crozet Islands using the same methodology and found no significant difference in SNW between sites for a given species. However, the SNW was significantly species-specific with a threefold increase from T. quinqueloba to Globigerina bulloides. The annual PIC:POC molar ratio of 0.07 was close to the mean ratio for the global ocean and lead to a low carbonate counter pump effect (~5%) compared to a previous study north of the PF (6-32%). We suggest that lowers counter pump effect south of the PF despite similar productivity levels is due to a dominance of coccoliths in the PIC fluxes and a difference in the foraminifers species assemblage with a predominance of polar species with lower SNW.

Spectrally narrowed laserlike emission in a novel organic salt, DEST: cooperative emission

NASA Astrophysics Data System (ADS)

Tan, Shida; Mishra, Alpana; Ahyi, Ayayi; Bhowmik, Achintya; Dharmadhikari, Aditya; Thakur, Mrinal

2001-03-01

We have synthesized a novel organic salt, 4'-diethylamino-N-methyl-4-stilbazolium p-toluenesulfonate (DEST). Frequency-doubled pulses (55 ps) from a Nd:YAG laser at 10 Hz repetition rate were used to pump DEST solution in methanol and a 20% conversion efficiency in laserlike emission was observed without external mirrors. The low energy PL quantum efficiency of DEST is very low. The peak of the emission spectrum was at 617 nm and the threshold pump energy for spectral-narrowing was less than 1 μJ. Beyond the threshold, the FWHM of the spectrum was found to have reduced from 70 nm to 14 nm The characteristics are similar to that of another organic salt, SPCD^1, which has been recently reported. Cooperative emission appears to play a dominant role in this emission process. 1. A. K. Bhowmik, A. Dharmadhikari, and M. Thakur, OSA Technical Digest, 467, CLEO (1999).

Salt-hydrate thermal-energy-storage system for space heating and air conditioning

NASA Astrophysics Data System (ADS)

MacCracken, C. D.; Armstrong, J. M.; MacCracken, M. M.; Silvetti, B. M.

1980-07-01

Latent heat storage equipment using three different salts was developed. The salts are: sodium sulfate pentahydrate which melts at 460 C, magnesium chloride hexahydrate which melts at 1150 C, and a eutectic combination of seven different materials which melts at 70 C. Stirring pumps, tanks, and tubing materials, and field filling of the salts into their tanks are developed. good performance for the tank/heat exchangers with all three salts is reported. Both the 1150 C and 460 C salts are almost equivalent in volume storage to water/ice. The 79.0 C salt, however, begins at about 56% of the BTU's per cubic foot of water/ice and declines due to separation to 40% after repeated cycling.

Test of salt marsh as a site of production and export of fish biomass with implications for impoundment management and restoration

USGS Publications Warehouse

Stevens, Philip W.

2002-01-01

Salt marshes are among the most productive ecosystems in the world, and although they are thought to enhance the productivity of open estuarine waters, the mechanism by which energy transfer occurs has been debated for decades. One possible mechanism is the transfer of saltmarsh production to estuarine waters by vagile fishes and invertebrates. Saltmarsh impoundments in the Indian River Lagoon, Florida, that have been reconnected to the estuary by culverts provide unique opportunities for studying marsh systems with respect to aquatic communities. The boundaries between salt marshes and the estuary are clearly defined by a system of dikes that confine fishes into a known area, and the exchange of aquatic organisms are restricted to culverts where they may be easily sampled. A multi-gear approach was used monthly to estimate fish standing stock, fish ingress/egress, and predation. Changes in saltmarsh fish abundance, and exchange with the estuary reflected the seasonal pattern of marsh flooding in the xv northern Indian River Lagoon system. During a six month period of marsh flooding, saltmarsh fishes had continuous access to marsh food resources. Piscivorous fishes regularly entered the marsh via creeks and ditches to prey upon marsh fishes, and piscivorous birds aggregated following major fish migrations to the marsh surface or to deep habitats. As water levels receded in winter, saltmarsh fishes concentrated into deep habitats and migration to the estuary ensued. The monthly estimates of fish standing stock, net fish ingress, and predation were used to develop a biomass budget to estimate annual production of fishes and the relative yield to predatory fish, birds, and direct migration to the estuary. Annual production of saltmarsh fishes was estimated to be 17.7 g·m-2 salt marsh, which falls within the range of previously reported values for estuarine fish communities. The relative yields were at least 21% to piscivorous fishes, 14% to piscivorous birds, and 32% to export. Annual export of fish biomass was 5.6 g fish·m-2 salt marsh, representing about 2% of saltmarsh primary production. Saltmarsh fishes convert marsh production to high quality vagile biomass (fishes concentrate energy, protein, and nutrients as body mass) and move this readily useable production to the estuary, providing an efficient link between salt marshes and estuarine predators.

Salt stress signals shape the plant root.

PubMed

Galvan-Ampudia, Carlos S; Testerink, Christa

2011-06-01

Plants use different strategies to deal with high soil salinity. One strategy is activation of pathways that allow the plant to export or compartmentalise salt. Relying on their phenotypic plasticity, plants can also adjust their root system architecture (RSA) and the direction of root growth to avoid locally high salt concentrations. Here, we highlight RSA responses to salt and osmotic stress and the underlying mechanisms. A model is presented that describes how salinity affects auxin distribution in the root. Possible intracellular signalling pathways linking salinity to root development and direction of root growth are discussed. These involve perception of high cytosolic Na+ concentrations in the root, activation of lipid signalling and protein kinase activity and modulation of endocytic pathways. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Development of new therapeutic strategy for transporter-related diseases].

PubMed

Hayashi, Hisamitsu

2014-01-01

Significant technological advances in gene sequence analysis and construction of genetically-modified animals during the last two decades made it possible to reveal that many transporters are associated with diseases. The bile salt export pump (BSEP/ABCB11), a member of the family of ATP-binding cassette transporters, is localized on the canalicular membrane of hepatocytes and predominantly mediates the biliary excretion of bile salts. A hereditary defect of BSEP results in severe cholestasis called progressive familial intrahepatic cholestasis type 2 (PFIC2). Without liver transplantation, this disease progresses to liver failure and death before adulthood; therefore the development of new, less invasive medical therapy for PFIC2 is of the highest priority. We have previously shown that in many cases of PFIC2 patients, the dysfunction of BSEP is attributable to decreased BSEP expression on the hepatocanalicular membrane and that 4-phenylbutyrate (4PB), an approved drug for urea cycle disorder, may be a compound with potential to restore BSEP expression. This drug inhibits ubiquitination of cell surface-resident BSEP and thereby its clathrin-mediated endocytosis through the AP2 adaptor complex, leading to increase in BSEP expression on the canalicular membrane. Clinical studies to investigate the efficacy of 4PB in the treatment of PFIC2 revealed that 4PB therapy biochemically and histologically improved liver function without any side effect. Therefore, 4PB therapy may become the preferred choice, instead of liver transplantation, for PFIC2 patients. The strategy employed and findings in this study would be valuable for the drug development of transporter-related disorders.

Supplementary report on the ground-water supplies of the Atlantic City region

USGS Publications Warehouse

Barksdale, Henry C.; Sundstrom, Raymond W.; Brunstein, Maurice S.

1936-01-01

At present more potable water is taken from the Atlantic City 800-foot sand than from any other source of supply for the region. This sand is the sole source for some of the smaller communities on the barrier beaches. The original static head of the water in it at Atlantic City was between 20 and 25 feet above sea level. The head has been lowered more than 50 feet over much of the region,  and in parts of Atlantic City it has been lowered considerably more than 100 feet. A consideration of the principles governing the relation between salt water and fresh water in water-bearing sands indicates that the 800-foot sand probably contained salt water at a distance of 5 or 10 miles out from Atlantic City before any water was pumped from it. The evidence collected in this investigation indicates that the cone of depression created by the pumping from this sand in the Atlantic City region has probably extended inland to the intake area of the sand, the nearest part of which is probably about 40 miles from Atlantic City. If this is so, the conclusion is almost inescapable that it has also extended oceanward for a distance considerably greater than the 5 or 10 miles to the original zone of contact between the fresh and salt waters, and that salt water is probably being drawn toward the Atlantic City region through this sand. The time of its arrival will depend primarily upon the rate of pumping in the region and upon how much of the fresh water that originally lay between the region and the zone of contact must be removed before the salt water can reach the region. It may arrive in the near future if it advances in the form of a narrow tongue. On the other hand, if it advances along a broader front; so that more of the intervening fresh water must be pumped out of the formation, its arrival may be delayed for some time.

Ground-water quality in the Santa Rita, Buellton, and Los Olivos hydrologic subareas of the Santa Ynez River basin, Santa Barbara County, California

USGS Publications Warehouse

Hamlin, S.N.

1985-01-01

Groundwater quality in the upper Santa Ynez River Valley in Santa Barbara County has degraded due to both natural and anthropogenic causes. The semiarid climate and uneven distribution of rainfall has limited freshwater recharge and caused salt buildup in water supplies. Tertiary rocks supply mineralized water. Agricultural activities (irrigation return flow containing fertilizers and pesticides, cultivation, feedlot waste disposal) are a primary cause of water quality degradation. Urban development, which also causes water quality degradation (introduced contaminants, wastewater disposal, septic system discharge, and land fill disposal of waste), has imposed stricter requirements on water supply quality. A well network was designed to monitor changes in groundwater quality related to anthropogenic activities. Information from this network may aid in efficient management of the groundwater basins as public water supplies, centered around three basic goals. First is to increase freshwater recharge to the basins by conjunctive surface/groundwater use and surface-spreading techniques. Second is to optimize groundwater discharge by efficient timing and spacing of pumping. Third is to control and reduce sources of groundwater contamination by regulating wastewater quality and distribution and, preferably, by exporting wastewaters from the basin. (USGS)

Coal-bed methane water effects on dill and essential oils

USDA-ARS?s Scientific Manuscript database

Pumping water from coal seams decreases the pressure in the seam and in turn releases trapped methane; this is the most common and economic way of methane extraction. The water that is pumped out is known as coal-bed methane water (CBMW), which is high in sodium and other salts. In past 25 years, th...

13. VIEW OF WESTERN CANAL EAST OF CARRIAGE LANE IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. VIEW OF WESTERN CANAL EAST OF CARRIAGE LANE IN TEMPE, SHOWING DROP STRUCTURE AND GROUNDWATER PUMP. THIS IS THE LAST OF FOUR PUMPS WHICH FEED DIRECTLY INTO THE CANAL BETWEEN ALMA SCHOOL ROAD AND PRICE ROAD. ON THIS DAY, ALL FOUR PUMPS, OPERATING AT FULL OUTPUT, HAVE CONSIDERABLY SWELLED THE FLOW TO THE CANAL. NOTE THE OLD FASHIONED BRICKWORK ON THE NORTH BANK. - Western Canal, South side of Salt River between Tempe, Phoenix & Mesa, Mesa, Maricopa County, AZ

Spin accumulation in thin Cs salts on contact with optically polarized Cs vapor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishikawa, Kiyoshi

2011-09-15

The spin angular momentum accumulates in the Cs nuclei of salt on contact with optically pumped Cs vapor. The spin polarization in stable chloride as well as dissociative hydride indicates that nuclear dipole interaction works in spin transferring with a lesser role of atom exchange. In the solid film, not only the spin buildup but also the decay of enhanced polarization is faster than the thermal recovery rate for the bulk salt. Eliminating the signal of thick salt, we find that the nuclear spin polarization in the chloride film reaches over 100 times the thermal equilibrium.

[Function of transport H+-ATPases in plant cell plasma and vacuolar membranes of maize under salt stress conditions and effect of adaptogenic preparations].

PubMed

Rybchenko, Zh I; Palladina, T O

2011-01-01

Participations of electrogenic H+-pumps of plasma and vacuolar membranes represented by E1-E2 and V-type H+-ATPases in plant cell adaptation to salt stress conditions has been studied by determination of their transport activities. Experiments were carried out on corn seedlings exposed during 1 or 10 days at 0.1 M NaCl. Preparations Methyure and Ivine were used by seed soaking at 10(-7) M. Plasma and vacuolar membrane fractions were isolated from corn seedling roots. In variants without NaCl a hydrolytical activity of plasma membrane H+-ATPase was increased with seedling age and its transport one was changed insignificantly, wherease the response of the weaker vacuolar H+-ATPase was opposite. NaCl exposition decreased hydrolytical activities of both H+-ATPases and increased their transport ones. These results demonstrated amplification of H+-pumps function especially represented by vacuolar H+-ATPase. Both preparations, Methyure mainly, caused a further increase of transport activity which was more expressed in NaCl variants. Obtained results showed the important role of these H+-pumps in plant adaptation under salt stress conditions realized by energetical maintenance of the secondary active Na+/H+ -antiporters which remove Na+ from cytoplasm.

The Novel Helicobacter pylori CznABC Metal Efflux Pump Is Required for Cadmium, Zinc, and Nickel Resistance, Urease Modulation, and Gastric Colonization

PubMed Central

Stähler, Frank Nils; Odenbreit, Stefan; Haas, Rainer; Wilrich, Julia; Vliet, Arnoud H. M. Van; Kusters, Johannes G.; Kist, Manfred; Bereswill, Stefan

2006-01-01

Maintaining metal homeostasis is crucial for the adaptation of Helicobacter pylori to the gastric environment. Iron, copper, and nickel homeostasis has recently been demonstrated to be required for the establishment of H. pylori infection in animal models. Here we demonstrate that the HP0969-0971 gene cluster encoding the Czc-type metal export pump homologs HP0969, HP0970, and the H. pylori-specific protein HP0971 forms part of a novel H. pylori metal resistance determinant, which is required for gastric colonization and for the modulation of urease activity. Insertional mutagenesis of the HP0971, HP0970, or HP0969 genes in H. pylori reference strain 26695 resulted in increased sensitivity to cadmium, zinc, and nickel (czn), suggesting that the encoded proteins constitute a metal-specific export pump. Accordingly, the genes were designated cznC (HP0971), cznB (HP0970), and cznA (HP0969). The CznC and CznA proteins play a predominant role in nickel homeostasis, since only the cznC and cznA mutants but not the cznB mutant displayed an 8- to 10-fold increase in urease activity. Nickel-specific affinity chromatography demonstrated that recombinant versions of CznC and CznB can bind to nickel and that the purified CznB protein interacted with cadmium and zinc, since both metals competitively inhibited nickel binding. Finally, single cznA, cznB, and cznC mutants did not colonize the stomach in a Mongolian gerbil-based animal model. This demonstrates that the metal export functions of H. pylori cznABC are essential for gastric colonization and underlines the extraordinary importance of metal ion homeostasis for the survival of H. pylori in the gastric environment. PMID:16790756

Replumbing of the Biological Pump caused by Millennial Climate Variability

NASA Astrophysics Data System (ADS)

Galbraith, E.; Sarmiento, J.

2008-12-01

It has been hypothesized that millennial-timescale variability in the biological pump was a critical instigator of glacial-interglacial cycles. However, even in the absence of changes in ecosystem function (e.g. due to iron fertilization), determining the mechanisms by which physical climate variability alters the biological pump is not simple. Changes in upper ocean circulation and deep water formation have previously been shown to alter both the downward flux of organic matter and the mass of respired carbon in the ocean interior, often in non- intuitive ways. For example, a reduced upward flux of nutrients at the global scale will decrease the global rate of export production, but it could either increase or decrease the respired carbon content of the ocean interior, depending on where the reduced upward flux of nutrients occurs. Furthermore, viable candidates for physical climate forcing are numerous, including changes in the westerly winds, changes in the depth of the thermocline, and changes in the formation rate of North Atlantic Deep Water, among others. We use a simple, prognostic, light-and temperature-dependent model of biogeochemical cycling within a state-of-the- art global coupled ocean-atmosphere model to examine the response of the biological pump to changes in the coupled Earth system over multiple centuries. The biogeochemical model explicitly distinguishes respired carbon from preformed and saturation carbon, allowing the activity of the biological pump to be clearly quantified. Changes are forced in the model by altering the background climate state, and by manipulating the flux of freshwater to the North Atlantic region. We show how these changes in the physical state of the coupled ocean-atmosphere system impact the distribution and mass of respired carbon in the ocean interior, and the relationship these changes bear to global patterns of export production via the redistribution of nutrients.

Revealing and analyzing networks of environmental systems

NASA Astrophysics Data System (ADS)

Eveillard, D.; Bittner, L.; Chaffron, S.; Guidi, L.; Raes, J.; Karsenti, E.; Bowler, C.; Gorsky, G.

2015-12-01

Understanding the interactions between microbial communities and their environment well enough to be able to predict diversity on the basis of physicochemical parameters is a fundamental pursuit of microbial ecology that still eludes us. However, modeling microbial communities is a complicated task, because (i) communities are complex, (ii) most are described qualitatively, and (iii) quantitative understanding of the way communities interacts with their surroundings remains incomplete. Within this seminar, we will illustrate two complementary approaches that aim to overcome these points in different manners. First, we will present a network analysis that focus on the biological carbon pump in the global ocean. The biological carbon pump is the process by which photosynthesis transforms CO2 to organic carbon sinking to the deep-ocean as particles where it is sequestered. While the intensity of the pump correlate to plankton community composition, the underlying ecosystem structure and interactions driving this process remain largely uncharacterized Here we use environmental and metagenomic data gathered during the Tara Oceans expedition to improve understanding of these drivers. We show that specific plankton communities correlate with carbon export and highlight unexpected and overlooked taxa such as Radiolaria, alveolate parasites and bacterial pathogens, as well as Synechococcus and their phages, as key players in the biological pump. Additionally, we show that the abundances of just a few bacterial and viral genes predict most of the global ocean carbon export's variability. Together these findings help elucidate ecosystem drivers of the biological carbon pump and present a case study for scaling from genes-to-ecosystems. Second, we will show preliminary results on a probabilistic modeling that predicts microbial community structure across observed physicochemical data, from a putative network and partial quantitative knowledge. This modeling shows that, despite distinct quantitative environmental perturbations, the constraints on community structure could remain stable.

Molten salt destruction of energetic waste materials

DOEpatents

Brummond, W.A.; Upadhye, R.S.; Pruneda, C.O.

1995-07-18

A molten salt destruction process is used to treat and destroy energetic waste materials such as high explosives, propellants, and rocket fuels. The energetic material is pre-blended with a solid or fluid diluent in safe proportions to form a fluid fuel mixture. The fuel mixture is rapidly introduced into a high temperature molten salt bath. A stream of molten salt is removed from the vessel and may be recycled as diluent. Additionally, the molten salt stream may be pumped from the reactor, circulated outside the reactor for further processing, and delivered back into the reactor or cooled and circulated to the feed delivery system to further dilute the fuel mixture entering the reactor. 4 figs.

Molten salt destruction of energetic waste materials

DOEpatents

Brummond, William A.; Upadhye, Ravindra S.; Pruneda, Cesar O.

1995-01-01

A molten salt destruction process is used to treat and destroy energetic waste materials such as high explosives, propellants, and rocket fuels. The energetic material is pre-blended with a solid or fluid diluent in safe proportions to form a fluid fuel mixture. The fuel mixture is rapidly introduced into a high temperature molten salt bath. A stream of molten salt is removed from the vessel and may be recycled as diluent. Additionally, the molten salt stream may be pumped from the reactor, circulated outside the reactor for further processing, and delivered back into the reactor or cooled and circulated to the feed delivery system to further dilute the fuel mixture entering the reactor.

Carbonate counter pump stimulated by natural iron fertilization in the Polar Frontal Zone

NASA Astrophysics Data System (ADS)

Salter, Ian; Schiebel, Ralf; Ziveri, Patrizia; Movellan, Aurore; Lampitt, Richard; Wolff, George A.

2014-12-01

The production of organic carbon in the ocean's surface and its subsequent downward export transfers carbon dioxide to the deep ocean. This CO2 drawdown is countered by the biological precipitation of carbonate, followed by sinking of particulate inorganic carbon, which is a source of carbon dioxide to the surface ocean, and hence the atmosphere over 100-1,000 year timescales. The net transfer of CO2 to the deep ocean is therefore dependent on the relative amount of organic and inorganic carbon in sinking particles. In the Southern Ocean, iron fertilization has been shown to increase the export of organic carbon, but it is unclear to what degree this effect is compensated by the export of inorganic carbon. Here we assess the composition of sinking particles collected from sediment traps located in the Polar Frontal Zone of the Southern Ocean. We find that in high-nutrient, low-chlorophyll regions that are characterized by naturally high iron concentrations, fluxes of both organic and inorganic carbon are higher than in regions with no iron fertilization. However, the excess flux of inorganic carbon is greater than that of organic carbon. We estimate that the production and flux of carbonate in naturally iron-fertilized waters reduces the overall amount of CO2 transferred to the deep ocean by 6-32%, compared to 1-4% at the non-fertilized site. We suggest that an increased export of organic carbon, stimulated by iron availability in the glacial sub-Antarctic oceans, may have been accompanied by a strengthened carbonate counter pump.

Sea salt irradiation experiments relevant to the surface conditions of ocean worlds such as Europa and Enceladus

NASA Astrophysics Data System (ADS)

Hand, Kevin P.; Carlson, Robert W.

2015-11-01

We have conducted a set of laboratory experiments to measure changes in NaCl, KCl, MgCl2, and mixtures of these salts, as a function of exposure to the temperature, pressure, and radiation conditions relevant to ice covered ocean worlds in our solar system. Reagent grade salts were placed onto a diffuse aluminum target at the end of a cryostat coldfinger and loaded into an ultra-high vacuum chamber. The samples were then cooled to 100 K and the chamber pumped down to ~10-8 Torr, achieving conditions comparable to the surface of several moons of the outer solar system. Samples were subsequently irradiated with 10 keV electrons at an average current of 1 µA.We examined a range of conditions for NaCl including pure salts grains (~300 µm diameter), salt grains with water ice deposited on top, and evaporites. For the evaporites saturated salt water was loaded onto the cryostat target, the chamber closed, and then slowly pumped down to remove the water, leaving behind a salt evaporate for irradiation.The electron bombardment resulted in the trapping of electrons in halogen vacancies, yielding the the F- and M- color centers. After irraditiation we observed yellow-brown discoloration in NaCl. KCl was observed to turn a distinct violet. In NaCl these centers have strong absorptions at 450 nm and 720 nm, respectively, providing a highly diagnostic signature of otherwise transparent alkali halides, making it possible to remotely characterize and quantify the composition and salinity of ocean worlds.

Chapter 5: Interdisciplinary land use along the Mogollon Rim

Treesearch

Malchus B. Baker; Peter F. Ffolliott

1999-01-01

The amount of water stored in the Salt River Project reservoirs during the middle 1950s was low and, as a consequence, apprehension arose among some residents of the Salt River Valley that a serious water shortage would soon occur. Groundwater supplies in the Valley were also being rapidly depleted, and pumping costs were steadily rising. Long-term studies at Sierra...

Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

PubMed Central

Shaha, Dinesh Chandra; Cho, Yang-Ki

2016-01-01

Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE. PMID:27255892

Soil bacteria confer plant salt tolerance by tissue-specific regulation of the sodium transporter HKT1.

PubMed

Zhang, Huiming; Kim, Mi-Seong; Sun, Yan; Dowd, Scot E; Shi, Huazhong; Paré, Paul W

2008-06-01

Elevated sodium (Na(+)) decreases plant growth and, thereby, agricultural productivity. The ion transporter high-affinity K(+) transporter (HKT)1 controls Na(+) import in roots, yet dysfunction or overexpression of HKT1 fails to increase salt tolerance, raising questions as to HKT1's role in regulating Na(+) homeostasis. Here, we report that tissue-specific regulation of HKT1 by the soil bacterium Bacillus subtilis GB03 confers salt tolerance in Arabidopsis thaliana. Under salt stress (100 mM NaCl), GB03 concurrently down- and upregulates HKT1 expression in roots and shoots, respectively, resulting in lower Na(+) accumulation throughout the plant compared with controls. Consistent with HKT1 participation in GB03-induced salt tolerance, GB03 fails to rescue salt-stressed athkt1 mutants from stunted foliar growth and elevated total Na(+) whereas salt-stressed Na(+) export mutants sos3 show GB03-induced salt tolerance with enhanced shoot and root growth as well as reduced total Na(+). These results demonstrate that tissue-specific regulation of HKT1 is critical for managing Na(+) homeostasis in salt-stressed plants, as well as underscore the breadth and sophistication of plant-microbe interactions.

1. AERIAL VIEW OF THE HIGHLINE PUMPING PLANT SITE ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. AERIAL VIEW OF THE HIGHLINE PUMPING PLANT SITE ON THE WESTERN CANAL, LOOKING NORTH. THE OLD PLANT IS ON THE RIGHT BANK, NEAREST THE CANAL. THE NEW PLANT IS ON THE LEFT BANK AT THE END OF THE INLET CANAL. THE KYRENE DITCH RUNS OUT OF THE BOTTOM OF THE PICTURE, AND PART OF THE SWITCHYARD FOR THE KYRENE STEAM PLANT IS VISIBLE AT LOWER RIGHT. c. 1955 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

Telemetric signal-driven servocontrol of renal perfusion pressure in acute and chronic rat experiments

PubMed Central

Xia, Min; Li, Pin-Lan; Li, Ningjun

2008-01-01

The present study was designed to take advantage of telemetry data acquisition and develop an easy and reliable system to servocontrol renal perfusion pressure (RPP). Digitized pressure signals from lower abdominal aorta in rats, reflecting RPP, was obtained by a telemetry device and dynamically exported into an Excel worksheet. A computer program (LabVIEW) compared the RPP data with a preselected pressure range and drove a bidirectional syringe pump to control the inflation of a vascular occluder around the aorta above renal arteries. When RPP was higher than the preselected range, the syringe pump inflated the occluder and decreased RPP, and vice versa. If RPP was within range, there was no action. In this way, RPP was servocontrolled within the desired range. In experiments with norepinephrine- or ANG II-induced acute increases in systemic arterial pressure (120–145 mmHg), the system controlled RPP at a constant range of 100–105 mmHg within 30–50 s and differentiated the pressure-dependent and -independent effects on renal functions. In Dahl S rats with high-salt-induced hypertension, this system maintained RPP at 100–120 mmHg over 10 days, while systemic arterial pressures were 150 ± 5.9 mmHg in uncontrolled animals. This system also has the ability of simultaneity and multiplexing to control multiple animals. Our results suggest that this is an effective and reliable system to servocontrol RPP, which can be easily established with general computer knowledge. This system provides a powerful tool and may greatly facilitate the studies in pressure-dependent/-independent effects of a variety of cardiovascular factors. PMID:18815205

Modelling the regulation effects of lowland polder with pumping station on hydrological processes and phosphorus loads.

PubMed

Yan, Renhua; Li, Lingling; Gao, Junfeng

2018-05-08

Exploring the hydrological regulation of a lowland polder is essential for increasing knowledge regarding the role of polders associated with pumping stations in lowlands. In this study, the Lowland Polder Hydrology and Phosphorus modelling System (PHPS) was applied to the Jianwei polder as a case study for quantifying the regulation effects of a lowland polder with pumping on discharge and phosphorus loads. The results indicate that the polder significantly affected the temporal distribution and annual amount of catchment discharge. Compared with a no-pumping scenario, an agricultural polder with pumping stations generated a sharper discharge hydrograph with higher peak-values and lower minimum-values, as well as an 8.6% reduction in average annual discharge. It also decreased the phosphorus export to downstream water bodies by 5.33 kg/hm 2 /yr because of widespread ditches and ponds, a lower hydraulic gradient, and increased retention times of surface water in ponds. Copyright © 2018 Elsevier B.V. All rights reserved.

Expression of an arabidopsis vacuolar H+-pyrophosphatase gene (AVP1) in cotton improves drought- and salt tolerance and increases fibre yield in the field conditions

USDA-ARS?s Scientific Manuscript database

The Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump on the vacuolar membrane. Overexpression of AVP1 in Arabidopsis, tomato and rice enhances plant performance under salt and drought stress conditions, because up-regulation of the type I H+-PPase from Arabid...

Expression of an Arabidopsis Vacuolar H+-pyrophosphatase Gene (AVP1) in Cotton Improves Drought- and Salt Tolerance and Increases Fibre Yield in the Field Conditions.

USDA-ARS?s Scientific Manuscript database

The Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump on the vacuolar membrane. Overexpression of AVP1 in Arabidopsis, tomato and rice enhances plant performance under salt and drought stress conditions, because up-regulation of the type I H+PPase from Arabido...

75 FR 71688 - Certain New Chemicals; Receipt and Status Information

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-24

... polyalkylene oxide. P-10-0575 09/27/10 12/25/10 Eastman Kodak (S) Polymer used in (G) Methacrylic acid Company. manufacture of polymer with imaging media/ isoalkylmethacrylam products; for ide, export. arylmethacrylate...) industrial coatings. Alkylenealkanedioic acid, polymer with alkenylbenzene and alkenenitrile, ammonium salt...

40 CFR 747.195 - Triethanolamine salt of a substituted organic acid.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., commerce, importer, impurity, Inventory, manufacturer, person, process, processor, and small quantities... control of the processor. (ii) Distribution in commerce is limited to purposes of export. (iii) The processor or distributor may not use the substance except in small quantities solely for research and...

Detergent Screening and Purification of the Human Liver ABC Transporters BSEP (ABCB11) and MDR3 (ABCB4) Expressed in the Yeast Pichia pastoris

PubMed Central

Stindt, Jan; Smits, Sander H. J.; Schmitt, Lutz

2013-01-01

The human liver ATP-binding cassette (ABC) transporters bile salt export pump (BSEP/ABCB11) and the multidrug resistance protein 3 (MDR3/ABCB4) fulfill the translocation of bile salts and phosphatidylcholine across the apical membrane of hepatocytes. In concert with ABCG5/G8, these two transporters are responsible for the formation of bile and mutations within these transporters can lead to severe hereditary diseases. In this study, we report the heterologous overexpression and purification of human BSEP and MDR3 as well as the expression of the corresponding C-terminal GFP-fusion proteins in the yeast Pichia pastoris. Confocal laser scanning microscopy revealed that BSEP-GFP and MDR3-GFP are localized in the plasma membrane of P. pastoris. Furthermore, we demonstrate the first purification of human BSEP and MDR3 yielding ∼1 mg and ∼6 mg per 100 g of wet cell weight, respectively. By screening over 100 detergents using a dot blot technique, we found that only zwitterionic, lipid-like detergents such as Fos-cholines or Cyclofos were able to extract both transporters in sufficient amounts for subsequent functional analysis. For MDR3, fluorescence-detection size exclusion chromatography (FSEC) screens revealed that increasing the acyl chain length of Fos-Cholines improved monodispersity. BSEP purified in n-dodecyl-β-D-maltoside or Cymal-5 after solubilization with Fos-choline 16 from P. pastoris membranes showed binding to ATP-agarose. Furthermore, detergent-solubilized and purified MDR3 showed a substrate-inducible ATPase activity upon addition of phosphatidylcholine lipids. These results form the basis for further biochemical analysis of human BSEP and MDR3 to elucidate the function of these clinically relevant ABC transporters. PMID:23593265

A micro-flow-batch analyzer with solenoid micro-pumps for the photometric determination of iodate in table salt.

PubMed

Lima, Marcelo B; Barreto, Inakã S; Andrade, Stéfani Iury E; Almeida, Luciano F; Araújo, Mário C U

2012-10-15

In this study, a micro-flow-batch analyzer (μFBA) with solenoid micro-pumps for the photometric determination of iodate in table salt is described. The method is based on the reaction of iodate with iodide to form molecular iodine followed by the reaction with N,N-diethyl-p-phenylenediamine (DPD). The analytical signal was measured at 520 nm using a green LED integrated into the μFBA built in the urethane-acrylate resin. The analytical curve for iodate was linear in the range of 0.01-10.0 mg L(-1) with a correlation coefficient of 0.997. The limit of detection and relative standard deviation were estimated at 0.004 mg L(-1) and<1.5% (n=3), respectively. The accuracy was assessed through recovery test (97.6-103.5%) and independent analysis by a conventional titrimetric method. Comparing this technique with the conventional method, no statistically significant differences were observed when applying the paired t-test at a 95% confidence level. The proposed microsystem using solenoid micro-pumps presented satisfactory robustness and high sampling rate (170 h(-1)), with a low reagents consumption and a low cost to build the device. The proposed microsystem is a new alternative for automatic determination of iodate in table salt, comparing satisfactory to the recently flow system. Copyright © 2012 Elsevier B.V. All rights reserved.

Uncoupling of the hnRNP Npl3p from mRNAs during the stress-induced block in mRNA export.

PubMed

Krebber, H; Taura, T; Lee, M S; Silver, P A

1999-08-01

Npl3p, the major mRNA-binding protein of the yeast Saccharomyces cerevisiae shuttles between the nucleus and the cytoplasm. A single amino acid change in the carboxyl terminus of Npl3p (E409 --> K) renders the mutant protein largely cytoplasmic because of a delay in its import into the nucleus. This import defect can be reversed by increasing the intracellular concentration of Mtr10p, the nuclear import receptor for Npl3p. Conversely, using this mutant, we show that Npl3p and mRNA export out of the nucleus is significantly slowed in cells bearing mutations in XPO1/CRM1, which encodes the export receptor for NES-containing proteins and in RAT7, which encodes an essential nucleoporin. Interestingly, following induction of stress by heat shock, high salt, or ethanol, conditions under which most mRNA export is blocked, Npl3p is still exported from the nucleus. The stress-induced export of Npl3p is independent of both the activity of Xpo1p and the continued selective export of heat-shock mRNAs that occurs following stress. UV-cross-linking experiments show that Npl3p is bound to mRNA under normal conditions, but is no longer RNA associated in stressed cells. Taken together, we suggest that the uncoupling of Npl3p and possibly other mRNA-binding proteins from mRNAs in the nucleus provides a general switch that regulates mRNA export. By this model, under normal conditions Npl3p is a major component of an export-competent RNP complex. However, under conditions of stress, Npl3p no longer associates with the export complex, rendering it export incompetent and thus nuclear.

Multidrug efflux pumps: the structures of prokaryotic ATP-binding cassette transporter efflux pumps and implications for our understanding of eukaryotic P-glycoproteins and homologues.

PubMed

Kerr, Ian D; Jones, Peter M; George, Anthony M

2010-02-01

One of the Holy Grails of ATP-binding cassette transporter research is a structural understanding of drug binding and transport in a eukaryotic multidrug resistance pump. These transporters are front-line mediators of drug resistance in cancers and represent an important therapeutic target in future chemotherapy. Although there has been intensive biochemical research into the human multidrug pumps, their 3D structure at atomic resolution remains unknown. The recent determination of the structure of a mouse P-glycoprotein at subatomic resolution is complemented by structures for a number of prokaryotic homologues. These structures have provided advances into our knowledge of the ATP-binding cassette exporter structure and mechanism, and have provided the template data for a number of homology modelling studies designed to reconcile biochemical data on these clinically important proteins.

Quantifying groundwater discharge through fringing wetlands to estuaries: Seasonal variability, methods comparison, and implications for wetland-estuary exchange

USGS Publications Warehouse

Tobias, C.R.; Harvey, J.W.; Anderson, I.C.

2001-01-01

Because groundwater discharge along coastal shorelines is often concentrated in zones inhabited by fringing wetlands, accurately estimating discharge is essential for understanding its effect on the function and maintenance of these ecosystems. Most previous estimates of groundwater discharge to coastal wetlands have been temporally limited and have used only a single approach to estimate discharge. Furthermore, groundwater input has not been considered as a major mechanism controlling pore-water flushing. We estimated seasonally varying groundwater discharge into a fringing estuarine wetland using three independent methods (Darcy's Law, salt balance, and Br- tracer). Seasonal patterns of discharge predicted by both Darcy's Law and the salt balance yielded similar seasonal patterns with discharge maxima and minima in spring and early fall, respectively. They differed, however, in the estimated magnitude of discharge by two- to fourfold in spring and by 10-fold in fall. Darcy estimates of mean discharge ranged between -8.0 and 80 L m-2 d-1, whereas the salt balance predicted groundwater discharge of 0.6 to 22 L m-2 d-1. Results from the Br- tracer experiment estimated discharge at 16 L m-2 d-t, or nearly equal to the salt balance estimate at that time. Based upon the tracer test, pore-water conductivity profiles, and error estimates for the Darcy and salt balance approaches, we concluded that the salt balance provided a more certain estimate of groundwater discharge at high flow (spring). In contrast, the Darcy method provided a more reliable estimate during low flow (fall). Groundwater flushing of pore water in the spring exported solutes to the estuary at rates similar to tidally driven surface exchange seen in previous studies. Based on pore-water turnover times, the groundwater-driven flux of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and NH4+ to the estuary was 11.9, 1.6, and 1.3 g C or g N m-2 wetland for the 90 d encompassing peak spring discharge. Groundwater-induced flushing of the wetland subsurface therefore represents an important mechanism by which narrow fringing marshes may seasonally relieve salt stress and export material to adjacent water masses.

Photocopy of drawing (this photograph is and 8' x10' copy ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of drawing (this photograph is and 8' x10' copy of an 8' x 10' negative; 1940 original architectural drawing located at Building No. 458, NAS Pensacola, Florida) Central power plant building No. 47, electrical work, salt water pumps, auxiliary bus and fire pump, plan, details and changes, sheet 1 of 1. - U.S. Naval Air Station, Power Plant, 328 South Avenue, Pensacola, Escambia County, FL

Mitral Valve Prolapse

MedlinePlus

... valve syndrome . What happens during MVP? Watch an animation of mitral valve prolapse When the heart pumps ( ... our brochures Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Enhanced open ocean storage of CO2 from shelf sea pumping.

PubMed

Thomas, Helmuth; Bozec, Yann; Elkalay, Khalid; de Baar, Hein J W

2004-05-14

Seasonal field observations show that the North Sea, a Northern European shelf sea, is highly efficient in pumping carbon dioxide from the atmosphere to the North Atlantic Ocean. The bottom topography-controlled stratification separates production and respiration processes in the North Sea, causing a carbon dioxide increase in the subsurface layer that is ultimately exported to the North Atlantic Ocean. Globally extrapolated, the net uptake of carbon dioxide by coastal and marginal seas is about 20% of the world ocean's uptake of anthropogenic carbon dioxide, thus enhancing substantially the open ocean carbon dioxide storage.

Themis - A solar power station

NASA Astrophysics Data System (ADS)

Hillairet, J.

The organization, goals, equipment, costs, and performance of the French Themis (Thermo-helio-electric-MW) project are outlined. The program was begun for both the domestic energy market and for export. The installation comprises a molten eutectic salt loop which receives heat from radiators situated in a central tower. The salt transfers the heat to water for steam generation of electricity. A storage tank holds enough molten salt to supply one day's reserve of power, 40 MWh. A field of heliostats directs the suns rays for an estimated 2400 hr/yr onto the central receiver aperture, while 11 additional parabolic concentrators provide sufficient heat to keep the salt reservoir at temperatures exceeding 200 C. In a test run of several months during the spring of 1982 the heliostats directed the sun's rays with an average efficiency of 75 percent, yielding 2.3 MW of power at a system efficiency of 20.5 percent in completely automatic operation.

Schedules of controlled substances: placement of 5-methoxy-N,N-dimethyltryptamine into Schedule I of the Controlled Substances Act. Final rule.

PubMed

2010-12-20

With the issuance of this final rule, the Deputy Administrator of the Drug Enforcement Administration (DEA) places the substance 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), including its salts, isomers and salts of isomers whenever the existence of such salts, isomers, and salts of isomers is possible, into schedule I of the Controlled Substances Act (CSA). This action by the DEA Deputy Administrator is based on a scheduling recommendation from the Assistant Secretary for Health of the Department of Health and Human Services (DHHS) and a DEA review indicating that 5-MeO-DMT meets the criteria for placement in schedule I of the CSA. This final rule will impose the criminal sanctions and regulatory controls of schedule I substances under the CSA on the manufacture, distribution, dispensing, importation, exportation, and possession of 5-MeO-DMT.

Regulation of hepatic bile acid transporters Ntcp and Bsep expression.

PubMed

Cheng, Xingguo; Buckley, David; Klaassen, Curtis D

2007-12-03

Sodium-taurocholate cotransporting polypeptide (Ntcp) and bile salt export pump (Bsep) are two key transporters for hepatic bile acid uptake and excretion. Alterations in Ntcp and Bsep expression have been reported in pathophysiological conditions. In the present study, the effects of age, gender, and various chemicals on the regulation of these two transporters were characterized in mice. Ntcp and Bsep mRNA levels in mouse liver were low in the fetus, but increased to its highest expression at parturition. After birth, mouse Ntcp and Bsep mRNA decreased by more than 50%, and then gradually increased to adult levels by day 30. Expression of mouse Ntcp mRNA and protein exhibit higher levels in female than male livers. No gender difference exists in BSEP/Bsep expression in human and mouse livers. Hormone replacements conducted in gonadectomized, hypophysectomized, and lit/lit mice indicate that female-predominant Ntcp expression in mouse liver is due to the inhibitory effect of male-pattern GH secretion, but not sex hormones. Ntcp and Bsep expression are in general resistant to induction by a large battery of microsomal enzyme inducers. Administration of cholestyramine increased Ntcp, whereas chenodeoxycholic acid (CDCA) increased Bsep mRNA expression. In conclusion, mouse Ntcp and Bsep are regulated by age, gender, cholestyramine, and bile acid, but resistant to induction by most microsomal enzyme inducers.

A Study on Pharmacokinetics of Bosentan with Systems Modeling, Part 1: Translating Systemic Plasma Concentration to Liver Exposure in Healthy Subjects.

PubMed

Li, Rui; Niosi, Mark; Johnson, Nathaniel; Tess, David A; Kimoto, Emi; Lin, Jian; Yang, Xin; Riccardi, Keith A; Ryu, Sangwoo; El-Kattan, Ayman F; Maurer, Tristan S; Tremaine, Larry M; Di, Li

2018-04-01

Understanding liver exposure of hepatic transporter substrates in clinical studies is often critical, as it typically governs pharmacodynamics, drug-drug interactions, and toxicity for certain drugs. However, this is a challenging task since there is currently no easy method to directly measure drug concentration in the human liver. Using bosentan as an example, we demonstrate a new approach to estimate liver exposure based on observed systemic pharmacokinetics from clinical studies using physiologically based pharmacokinetic modeling. The prediction was verified to be both accurate and precise using sensitivity analysis. For bosentan, the predicted pseudo steady-state unbound liver-to-unbound systemic plasma concentration ratio was 34.9 (95% confidence interval: 4.2, 50). Drug-drug interaction (i.e., CYP3A and CYP2B6 induction) and inhibition of hepatic transporters (i.e., bile salt export pump, multidrug resistance-associated proteins, and sodium-taurocholate cotransporting polypeptide) were predicted based on the estimated unbound liver tissue or plasma concentrations. With further validation and refinement, we conclude that this approach may serve to predict human liver exposure and complement other methods involving tissue biopsy and imaging. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Ku proteins function as corepressors to regulate farnesoid X receptor-mediated gene expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohno, Masae; Kunimoto, Masaaki; Nishizuka, Makoto

2009-12-18

The farnesoid X receptor (FXR; NR1H4) is a member of the nuclear receptor superfamily and regulates the expression of genes involved in enterohepatic circulation and the metabolism of bile acids. Based on functional analyses, nuclear receptors are divided into regions A-F. To explore the cofactors interacting with FXR, we performed a pull-down assay using GST-fused to the N-terminal A/B region and the C region, which are required for the ligand-independent transactivation and DNA-binding, respectively, of FXR, and nuclear extracts from HeLa cells. We identified DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Ku80, and Ku70 as FXR associated factors. These proteins aremore » known to have an important role in DNA repair, recombination, and transcription. DNA-PKcs mainly interacted with the A/B region of FXR, whereas the Ku proteins interacted with the C region and with the D region (hinge region). Chromatin immunoprecipitation assays revealed that the Ku proteins associated with FXR on the bile salt export pump (BSEP) promoter. Furthermore, we demonstrated that ectopic expression of the Ku proteins decreased the promoter activity and expression of BSEP gene mediated by FXR. These results suggest that the Ku proteins function as corepressors for FXR.« less

Menadione metabolism to thiodione in hepatoblastoma by scanning electrochemical microscopy

PubMed Central

Mauzeroll, Janine; Bard, Allen J.; Owhadian, Omeed; Monks, Terrence J.

2004-01-01

The cytotoxicity of menadione on hepatocytes was studied by using the substrate generation/tip collection mode of scanning electrochemical microscopy by exposing the cells to menadione and detecting the menadione-S-glutathione conjugate (thiodione) that is formed during the cellular detoxication process and is exported from the cell by an ATP-dependent pump. This efflux was electrochemically detected and allowed scanning electrochemical microscopy monitoring and imaging of single cells and groups of highly confluent live cells. Based on a constant flux model, ≈6 × 106 molecules of thiodione per cell per second are exported from monolayer cultures of Hep G2 cells. PMID:15601769

Summary of ground-water conditions in the Jaffna Peninsula, Republic of Sri Lanka, with a plan for investigating feasibility of ground-water development

USGS Publications Warehouse

Meisler, Harold

1977-01-01

Ground water in the Jaffna Peninsula of Sri Lanka, Ceylon, occurs within solution openings of the Jaffna Limestone of Miocene age. The freshwater forms a complex of lenses up to 25 meters thick overlying saline water derived from the sea. Salt-water intrusion and upconing of the salt water has occurred at several locations primarily along the coast. Recharge to the aquifer occurs during October-December. Discharge is primarily to wells and to springs along the north coast. Spring discharge is small compared to withdrawal from wells. Pumping from wells in an intensively studied 142-square-kilometer area of the Peninsula was 55.5 million cubic meters in 1976, whereas discharge to visible springs was an estimated 9.3 million cubic meters. Pumping during January-September removes water from storage causing heads to decline and the salt water-freshwater interface to rise. The storage is replenished as heads increase and the interface is depressed during the following October-December. Consequently, most of the recharge goes into storage rather than discharging to the sea. (Woodard-USGS)

Long-Term High-Level Defense-Waste technology

NASA Astrophysics Data System (ADS)

1982-07-01

In the residual liquid solidification effort, the primary alternative studied is the wiped film evaporator approach to solidifying salt well pumped liquids and returning the molten material to single shell tanks for microwave final stabilization to a hard dry product. Both systems analysis and experimental work are proceeding to evaluate this approach. The primary alternative for in situ stabilization of in-tank wastes is microwave drying of wet salt cake and unpumped sludges. Experimental work was successfully conducted on a 1/12 scale tank containing wet synthetic salt cake. Related systems analysis of a full scale system was initiated.

Efflux systems in bacteria and their metabolic engineering applications.

PubMed

Jones, Christopher M; Hernández Lozada, Néstor J; Pfleger, Brian F

2015-11-01

The production of valuable chemicals from metabolically engineered microbes can be limited by excretion from the cell. Efflux is often overlooked as a bottleneck in metabolic pathways, despite its impact on alleviating feedback inhibition and product toxicity. In the past, it has been assumed that endogenous efflux pumps and membrane porins can accommodate product efflux rates; however, there are an increasing number of examples wherein overexpressing efflux systems is required to improve metabolite production. In this review, we highlight specific examples from the literature where metabolite export has been studied to identify unknown transporters, increase tolerance to metabolites, and improve the production capabilities of engineered bacteria. The review focuses on the export of a broad spectrum of valuable chemicals including amino acids, sugars, flavins, biofuels, and solvents. The combined set of examples supports the hypothesis that efflux systems can be identified and engineered to confer export capabilities on industrially relevant microbes.

13. Photocopy of drawing (original in SRP Files and Reproductions) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Photocopy of drawing (original in SRP Files and Reproductions) SRP Engineering, September 1940 RIGHTS OF WAY OF GRAND CANAL AND INDIAN BEND PUMP AND WASTE DITCH, SHOWING LOCATIONS OF DIESEL PLANT, ORIGINAL CROSSCUT HYDRO POWER HOUSE, AND DIESEL PLANT WELL NEAR WHICH INDIAN BEND POND WOULD BE CONSTRUCTED. - Crosscut Steam Plant, Indian Bend Pond & Pump Ditch, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

Quantifying export production in the Southern Ocean: Implications for the Baxs proxy

NASA Astrophysics Data System (ADS)

Hernandez-Sanchez, Maria T.; Mills, Rachel A.; Planquette, HéLèNe; Pancost, Richard D.; Hepburn, Laura; Salter, Ian; Fitzgeorge-Balfour, Tania

2011-12-01

The water column and sedimentary Baxs distribution around the Crozet Plateau is used to decipher the controls and timing of barite formation and to evaluate how export production signals are recorded in sediments underlying a region of natural Fe fertilization within the Fe limited Southern Ocean. Export production estimated from preserved, vertical sedimentary Baxs accumulation rates are compared with published export fluxes assessed from an integrated study of the biological carbon pump to determine the validity of Baxs as a quantitative proxy under different Fe supply conditions typical of the Southern Ocean. Detailed assessment of the geochemical partitioning of Ba in sediments and the lithogenic end-member allows appropriate correction of the bulk Ba content and determination of the Baxs content of sediments and suspended particles. The upper water column distribution of Baxs is extremely heterogeneous spatially and temporally. Organic carbon/Baxs ratios in deep traps from the Fe fertilized region are similar to other oceanic settings allowing quantification of the inferred carbon export based on established algorithms. There appears to be some decoupling of POC and Ba export in the Fe limited region south of the Plateau. The export production across the Crozet Plateau inferred from the Baxs sedimentary proxy indicates that the Fe fertilized area to the north of the Plateau experiences enhanced export relative to equivalent Southern Ocean settings throughout the Holocene and that this influence may also have impacted the site to the south for significant periods. This interpretation is corroborated by alternative productivity proxies (opal accumulation, 231Paxs/230Thxs). Baxs can be used to quantify export production in complex settings such as naturally Fe-fertilized (volcanoclastic) areas, providing appropriate lithogenic correction is undertaken, and sediment focusing is corrected for along with evaluation of barite preservation.

Travelers' Health: Water Disinfection for Travelers

MedlinePlus

... hand-pump or gravity-drip filters with various designs and types of filter media are commercially available ... salts, thus achieving desalination. One new portable filter design incorporates hollow fiber technology, which is a cluster ...

Structures of the TetR-like simocyclinone efflux pump repressor, SimR, and the mechanism of ligand-mediated derepression.

PubMed

Le, Tung B K; Stevenson, Clare E M; Fiedler, Hans-Peter; Maxwell, Anthony; Lawson, David M; Buttner, Mark J

2011-04-22

Simocyclinone D8 (SD8), a potent DNA gyrase inhibitor made by Streptomyces antibioticus, is exported from the producing organism by the SimX efflux pump. The expression of simX is under the control of SimR, a member of the TetR family of transcriptional regulators. SimR represses simX transcription by binding to operators in the intergenic region between simR and simX. Previously, we have shown that the mature antibiotic SD8 or its biosynthetic intermediate, simocyclinone C4, can dissociate SimR from its operators, leading to derepression of simX and export of SD8 from the cell. This provides a mechanism that couples the biosynthesis of the antibiotic to its export. Here, we report the crystal structures of SimR alone and in complex with either SD8 or simocyclinone C4. The ligand-binding pocket is unusual compared to those of other characterized TetR-family transcriptional regulators: the structures show an extensive ligand-binding pocket spanning both monomers in the functional dimeric unit, with the aminocoumarin moiety of SD8 buried in the protein core, while the angucyclic polyketide moiety is partially exposed to bulk solvent. Through comparisons of the structures, we postulate a derepression mechanism for SimR that invokes rigid-body motions of the subunits relative to one another, coupled with a putative locking mechanism to restrict further conformational change. Copyright © 2011 Elsevier Ltd. All rights reserved.

Estimates of micro-, nano-, and picoplankton contributions to particle export in the northeast Pacific

NASA Astrophysics Data System (ADS)

Mackinson, B. L.; Moran, S. B.; Lomas, M. W.; Stewart, G. M.; Kelly, R. P.

2015-06-01

The contributions of micro-, nano-, and picoplankton to particle export were estimated from measurements of size-fractionated particulate 234Th, organic carbon, and phytoplankton indicator pigments obtained during five cruises between 2010 and 2012 along Line P in the subarctic northeast Pacific Ocean. Sinking fluxes of particulate organic carbon (POC) and indicator pigments were calculated from 234Th-238U disequilibria and, during two cruises, measured by a sediment trap at Ocean Station Papa. POC fluxes at 100 m ranged from 0.65 to 7.95 mmol m-2 d-1, similar in magnitude to previous results at Line P. Microplankton pigments dominate indicator pigment fluxes (averaging 69 ± 19% of total pigment flux), while nanoplankton pigments comprised the majority of pigment standing stocks (averaging 64 ± 23% of total pigment standing stocks). Indicator pigment loss rates (the ratio of pigment export flux to pigment standing stocks) point to preferential export of larger microplankton relative to smaller nano- and picoplankton. However, indicator pigments do not quantitatively trace particle export resulting from zooplankton grazing, which may be an important pathway for the export of small phytoplankton. These results have important implications for understanding the magnitude and mechanisms controlling the biological pump at Line P in particular, and more generally in oligotrophic gyres and high-nutrient, low-chlorophyll (HNLC) regions where small phytoplankton represent a major component of the autotrophic community.

Estimates of micro-, nano-, and picoplankton contributions to particle export in the northeast Pacific

NASA Astrophysics Data System (ADS)

Mackinson, B. L.; Moran, S. B.; Lomas, M. W.; Stewart, G. M.; Kelly, R. P.

2014-08-01

The contributions of micro-, nano-, and picoplankton to particle export were estimated from measurements of size-fractionated particulate 234Th, organic carbon, and phytoplankton indicator pigments obtained during five cruises between 2010 and 2012 along Line P in the subarctic northeast Pacific Ocean. Sinking fluxes of particulate organic carbon (POC) and indicator pigments were calculated from 234Th-238U disequilibria and, during two cruises, measured by sediment trap at Ocean Station Papa. POC fluxes at 100 m ranged from 0.65-7.95 mmol m-2 d-1, similar in magnitude to previous results at Line P. Microplankton pigments dominate indicator pigment fluxes (averaging 69 ± 19% of total pigment flux), while nanoplankton pigments comprised the majority of pigment standing stocks (averaging 64 ± 23% of total pigment standing stock). Indicator pigment loss rates (the ratio of pigment export flux to pigment standing stock) point to preferential export of larger microplankton relative to smaller nano- and picoplankton. However, indicator pigments do not quantitatively trace particle export resulting from zooplankton grazing, which may be an important pathway for the export of small phytoplankton. These results have important implications for understanding the magnitude and mechanisms controlling the biological pump at Line P in particular, and more generally in oligotrophic gyres and high-nutrient, low-chlorophyll regions where small phytoplankton represent a major component of the autotrophic community.

Salt power - Is Neptune's ole salt a tiger in the tank

NASA Astrophysics Data System (ADS)

Wick, G. S.

1980-02-01

Methods of exploiting the 24 atm osmotic pressure difference between fresh and salt water to generate energy include reverse electrodialysis, wherein 80 millivolts of electricity cross each ion-selective membrane placed between solutions of fresh and salt water. Pressure-retarded osmosis, using pumps and pressure chambers, relies on semipermeable membranes that allow fresh water to flow into saline, with power generated by the permeated water being released through a turbine. In reverse vapor compression, water vapor rapidly transfers from fresh water to salt water in an evacuated chamber (due to the vapor pressure difference between them), and power can be extracted using 24 m diameter turbine blades. Environmental concerns include protecting estuaries from stress, managing sediments, and protecting marine animals, while filtration would be needed to keep the membranes free from corrosion, biological fouling, or silting.

Hyperpolarization of {sup 133}Cs nuclei enhanced by ion movement in a cesium salt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishikawa, Kiyoshi

2011-12-15

Hyperpolarization of {sup 133}Cs nuclei in CsCl salt is achieved through spin transfer from an optically pumped Cs vapor, with maximum polarizations of 0.1% demonstrated. Motional narrowing of the enhanced NMR line indicates that ion movement facilitates this process by transporting spin-polarized ions from the interface into the salt. The resulting NMR enhancement allows measurement of the polarization and its dynamics in real time. Based upon the NMR frequency and the longitudinal spin relaxation time, we find no evidence that the salt is contaminated by Cs metal or paramagnetic impurities. The Cs nuclear polarization reported here could be improved severalmore » orders of magnitude by intense laser heating of the entire sample.« less

Larval salinity tolerance of the South American salt-marsh crab, Neohelice (Chasmagnathus) granulata: physiological constraints to estuarine retention, export and reimmigration

NASA Astrophysics Data System (ADS)

Anger, Klaus; Spivak, Eduardo; Luppi, Tomás; Bas, Claudia; Ismael, Deborah

2008-06-01

The semiterrestrial crab Neohelice (= Chasmagnathus) granulata (Dana 1851) is a predominant species in brackish salt marshes, mangroves and estuaries. Its larvae are exported towards coastal marine waters. In order to estimate the limits of salinity tolerance constraining larval retention in estuarine habitats, we exposed in laboratory experiments freshly hatched zoeae to six different salinities (5 32‰). At 5‰, the larvae survived for a maximum of 2 weeks, reaching only exceptionally the second zoeal stage, while 38% survived to the megalopa stage at 10‰. Shortest development and negligible mortality occurred at all higher salt concentrations. These observations show that the larvae of N. granulata can tolerate a retention in the mesohaline reaches of estuaries, with a lower limit of ca. 10 15‰. Maximum survival at 25‰ suggests that polyhaline conditions rather than an export to oceanic waters are optimal for successful larval development of this species. In another experiment, we tested the capability of the last zoeal stage (IV) for reimmigration from coastal marine into brackish waters. Stepwise reductions of salinity during this stage allowed for moulting to the megalopa at 4 10‰. Although survival was at these conditions reduced and development delayed, these results suggest that already the zoea-IV stage is able to initiate the reimmigration into estuaries. After further salinity reduction, megalopae survived in this experiment for up to >3 weeks in freshwater, without moulting to juvenile crabs. In a similar experiment starting from the megalopa stage, successful metamorphosis occurred at 4 10‰, and juvenile growth continued in freshwater. Although these juvenile crabs showed significantly enhanced mortality and smaller carapace width compared to a seawater control, our results show that the late larval and early juvenile stages of N. granulata are well adapted for successful recruitment in brackish and even limnetic habitats.

High-frequency monitoring reveals nutrient sources and transport processes in an agriculture-dominated lowland water system

NASA Astrophysics Data System (ADS)

van der Grift, Bas; Broers, Hans Peter; Berendrecht, Wilbert; Rozemeijer, Joachim; Osté, Leonard; Griffioen, Jasper

2016-05-01

Many agriculture-dominated lowland water systems worldwide suffer from eutrophication caused by high nutrient loads. Insight in the hydrochemical functioning of embanked polder catchments is highly relevant for improving the water quality in such areas or for reducing export loads to downstream water bodies. This paper introduces new insights in nutrient sources and transport processes in a polder in the Netherlands situated below sea level using high-frequency monitoring technology at the outlet, where the water is pumped into a higher situated lake, combined with a low-frequency water quality monitoring programme at six locations within the drainage area. Seasonal trends and short-scale temporal dynamics in concentrations indicated that the NO3 concentration at the pumping station originated from N loss from agricultural lands. The NO3 loads appear as losses via tube drains after intensive rainfall events during the winter months due to preferential flow through the cracked clay soil. Transfer function-noise modelling of hourly NO3 concentrations reveals that a large part of the dynamics in NO3 concentrations during the winter months can be related to rainfall. The total phosphorus (TP) concentration and turbidity almost doubled during operation of the pumping station, which points to resuspension of particulate P from channel bed sediments induced by changes in water flow due to pumping. Rainfall events that caused peaks in NO3 concentrations did not results in TP concentration peaks. The rainfall induced and NO3 enriched quick interflow, may also be enriched in TP but retention of TP due to sedimentation of particulate P then results in the absence of rainfall induced TP concentration peaks. Increased TP concentrations associated with run-off events is only observed during a rainfall event at the end of a freeze-thaw cycle. All these observations suggest that the P retention potential of polder water systems is primarily due to the artificial pumping regime that buffers high flows. As the TP concentration is affected by operation of the pumping station, timing of sampling relative to the operating hours of the pumping station should be accounted for when calculating P export loads, determining trends in water quality, or when judging water quality status of polder water systems.

Summaries of Papers Presented at the High Resolution Spectroscopy Topical Meeting Held in Salt Lake City, Utah on 18-21 January 1993. Technical Digest Series. Volume 1. Postconference Edition

DTIC Science & Technology

1994-05-01

ViW 0 AN Nannvahv Aemawat f fle Vmd Y-k MfrWon, CA Fbnamuy 1923) Po.&vnfaum eitian SBN 1-552-,).4 [US Lis Pric $92 / OSA Mem *&ePric $M0 O~p " a ndlb r...cited effect lies in the basis of nonlinear polarization spectroscopy(NPS) and optically heterodyned polarization spectroscopy( OHPS ). Usually the pump...let us analyze the scheme of OHPS with elliptically polarized pumping. When the probe wave Is linearly polarized at x/ 4 to the major axis of the pump

Structures and transport dynamics of a Campylobacter jejuni multidrug efflux pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Chih-Chia; Yin, Linxiang; Kumar, Nitin

2017-08-01

Resistance-nodulation-cell division efflux pumps are integral membrane proteins that catalyze the export of substrates across cell membranes. Within the hydrophobe-amphiphile efflux subfamily, these resistance-nodulation-cell division proteins largely form trimeric efflux pumps. The drug efflux process has been proposed to entail a synchronized motion between subunits of the trimer to advance the transport cycle, leading to the extrusion of drug molecules. Here we use X-ray crystallography and single-molecule fluorescence resonance energy transfer imaging to elucidate the structures and functional dynamics of the Campylobacter jejuni CmeB multidrug efflux pump. We find that the CmeB trimer displays a very unique conformation. A directmore » observation of transport dynamics in individual CmeB trimers embedded in membrane vesicles indicates that each CmeB subunit undergoes conformational transitions uncoordinated and independent of each other. On the basis of our findings and analyses, we propose a model for transport mechanism where CmeB protomers function independently within the trimer.« less

Chemistry of Western Atlantic Precipitation at the Mid-Atlantic Coast and on Bermuda

DOE Office of Scientific and Technical Information (OSTI.GOV)

Church, T.M.; Galloway, J.N.; Jickells, T.D.

1982-12-20

The major ion composition of western Atlantic precipitation falling at the coast of eastern United States (Lewes, Delaware) and at the Sargasso Sea (Bermuda Island) has been measured by event year round (May 1980 to April 1981) to assess the influence of the ocean on precipitation from storms that leave the North American continent and transit over the western Atlantic. Particular attention is paid to the oceanic influence on the sulfur and nitrogen precursors of 'acid rains.' While sea salt contributes over half (by weight) of the salt in precipitation at the coast and over three quarters at Bermuda, mostmore » of the sulfate (90% at the coast and 50% at Bermuda) is in excess to sea salt sodium. Since Bermuda precipitation is still acidified some factor of 8 relative to pure equilibrium with atmospheric carbon dioxide, this strong acidity has been attributed to the long-range transport sulfur and nitrogen precursors in the marine troposphere during which the sulfuric acid component dominates. A sulfur budget for the western Atlantic troposphere shows that of the total amount of sulfur exported from the North American continuent (>3.9 TgS/yr) less than 3% (0.1 TgS/yr) is from natural sources, the rest being from anthropogenic emissions. If Bermuda precipitation is taken as typical of wet fallout of sulfur over the western Atlantic, then no more than half (<2 TgS/yr) of north American excess (nonsea salt) sulfur export falls out to the western Atlantic and at least half undergoes potential transoceanic tranport as acid rain precursors to the east of Bermuda.« less

Chemistry of western Atlantic precipitation at the mid-Atlantic coast and on Bermuda

DOE Office of Scientific and Technical Information (OSTI.GOV)

Church, T.M.; Galloway, J.N.; Jickells, T.D.

1982-12-20

The major ion composition of western Atlantic precipitation falling at the coast of eastern United States (Lewes, Delaware) and at the Sargasso Sea (Bermuda Island) has been measured by event year round (May 1980 to April 1981) to assess the influence of the ocean on precipitation from storms that leave the North American continent and transit over the western Atlantic. Particular attention is paid to the oceanic influence on the sulfur and nitrogen precursors of acid rains. While sea salt contributes over half (by weight) of the salt in precipitation at the coast and over three quarters at Bermuda, mostmore » of the sulfate (90% at the coast and 50% at Bermuda) is in excess to sea salt sodium. Since Bermuda precipitation is still acidified some factor of 8 relative to pure equilibrium with atmospheric carbon dioxide, this strong acidity has been attributed to the long-range transport sulfur and nitrogen precursors in the marine troposphere during which the sulfuric acid component dominates. A sulfur budget for the western Atlantic troposphere shows that of the total amount of sulfur exported from the North American continent (>3.9 TgS/yr) less than 3% (0.1 TgS/yr) is from natural sources, the rest being from anthropogenic emissions. If Bermuda precipitation is taken as typical of wet fallout of sulfur over the western Atlantic, then no more than half (<2 TgS/yr) of North American excess (nonsea salt) sulfur export falls out to the western Atlantic and at least half undergoes potential transoceanic transport as acid rain precursors to the east of Bermuda.« less

Mechanical Controls on Halokinesis in Layered Evaporite Sequences: Insights from 2D Geomechanical Forward Models

NASA Astrophysics Data System (ADS)

Goteti, Rajesh; Agar, Susan M.; Brown, John P.; Ball, Philip; Zuhlke, Rainer

2017-04-01

Mechanical stratification in LES (Layered Evaporate Sequences) can have a distinct impact on structural and depositional styles in rifted margin salt tectonics. The bulk mechanical response of an LES under geological loading is dependent, among other factors, on the relative proportions of salt and sediment, salt mobility and sedimentation rate. To assess the interactions among the aforementioned factors in a physically consistent manner, we present 2D, large-strain finite element models of an LES salt minibasin and diapirs. Loading from the deposition of alternating salt and sediment layers (i.e., LES), gravity and a prescribed geothermal gradient provide the driving force for halokinesis in the models. To accurately capture the mechanical impact of stratification within the modeled LES, salt is assigned a temperature-dependent visco-plastic rheology, whereas the sediments are assigned a non-associative cap-plasticity model that supports both compaction and shear localization. Perturbations in the initial salt-sediment interface are used to initiate the salt diapirs. Model results suggest that active diapirism in the basal halite layer initiates when the pressure at the base of the incipient salt diapir exceeds that beneath the minibasin. Vertical growth of the diapir is also accompanied by its lateral expansion at higher structural levels where it preferentially intrudes the adjacent pre- and syn-kinematic salt layers. This pressure pumping of deeper salt into shallow salt layers, can result in rapid thickness changes between successive sediment layers within the LES. Caution needs to be exercised as such thickness changes observed in seismic images may not be entirely due to the shifting of depocenters but also due to the lateral pumping of salt within the LES. The presence of salt layers at multiple structural levels decouples the deformation between successive clastic layers resulting in disharmomic folding with contrasting strain histories in the sedimentary stringers. A significant proportion of the bulk deviatoric strain is preferentially partitioned into the salt layers. Effective plastic shear strains within the sediment stringers generally remain low in the minibasin but can be significantly higher with attendant intense folding near the diapirs. In non-LES systems, the shape of a salt diapir is often used as indicator of relative rates of salt supply and sedimentation over geological time. However our models suggest that this rule-of-thumb may not apply in LES where the shape of the salt diapir is a function of the mechanical properties of the salt layers at various structural levels in addition to the relative rates of salt supply and sedimentation. Imaging challenges in LES may preclude placing strong constraints on structural timing based on interpretation of interfaces between the stringers and the salt diapir. In such situations, geomechanical forward modeling can be a useful tool in placing physics-based quantitative constraints on the timing of LES structures.

Analog Model Study of Ground-Water Flow in the Rehoboth Bay Area, Delaware.

DTIC Science & Technology

The study concerns ground- water flow in the Rehoboth Bay area, Delaware, a coastal area which depends on ground water for its fresh- water supply...Increased pumping demands may threaten to lower the water table and allow salt- water intrusion into the wells. The study was conducted using a viscous...use two different glycerin solutions to make observations and predict interactions between fresh and salt water in nature. Results indicate the

Physics of Spin-Polarized Media

DTIC Science & Technology

2007-11-21

midsection of the cell serving as the cathode, and liquid molten salt outside the cell serving as the anode [5]. This new method is very promising for of...filling atomic clock and magnetometer cells by electrolysis through the glass walls; (6) new investigations of optical pumping and magnetic resonances...cesium vapor can be used to polarize 3 Cs nuclei in CsH salt that coats the walls of a vapor cell. This result, an important first step, has been

Analysis of trace inorganic anions in weak acid salts by single pump cycling-column-switching ion chromatography.

PubMed

Huang, Zhongping; Ni, Chengzhu; Zhu, Zhuyi; Pan, Zaifa; Wang, Lili; Zhu, Yan

2015-05-01

The application of ion chromatography with the single pump cycling-column-switching technique was described for the analysis of trace inorganic anions in weak acid salts within a single run. Due to the hydrogen ions provided by an anion suppressor electrolyzing water, weak acid anions could be transformed into weak acids, existing as molecules, after passing through the suppressor. Therefore, an anion suppressor and ion-exclusion column were adopted to achieve on-line matrix elimination of weak acid anions with high concentration for the analysis of trace inorganic anions in weak acid salts. A series of standard solutions consisting of target anions of various concentrations from 0.005 to 10 mg/L were analyzed, with correlation coefficients r ≥ 0.9990. The limits of detection were in the range of 0.67 to 1.51 μg/L, based on the signal-to-noise ratio of 3 and a 25 μL injection volume. Relative standard deviations for retention time, peak area, and peak height were all less than 2.01%. A spiking study was performed with satisfactory recoveries between 90.3 and 104.4% for all anions. The chromatographic system was successfully applied to the analysis of trace inorganic anions in five weak acid salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solution of heat removal from nuclear reactors by natural convection

NASA Astrophysics Data System (ADS)

Zitek, Pavel; Valenta, Vaclav

2014-03-01

This paper summarizes the basis for the solution of heat removal by natural convection from both conventional nuclear reactors and reactors with fuel flowing coolant (such as reactors with molten fluoride salts MSR).The possibility of intensification of heat removal through gas lift is focused on. It might be used in an MSR (Molten Salt Reactor) for cleaning the salt mixture of degassed fission products and therefore eliminating problems with iodine pitting. Heat removal by natural convection and its intensification increases significantly the safety of nuclear reactors. Simultaneously the heat removal also solves problems with lifetime of pumps in the primary circuit of high-temperature reactors.

The impact on atmospheric CO2 of iron fertilization induced changes in the ocean's biological pump

NASA Astrophysics Data System (ADS)

Jin, X.; Gruber, N.; Frenzel, H.; Doney, S. C.; McWilliams, J. C.

2007-10-01

Using numerical simulations, we quantify the impact of changes in the ocean's biological pump on the air-sea balance of CO2 by fertilizing a small surface patch in the high-nutrient, low-chlorophyll region of the eastern tropical Pacific with iron. Decade-long fertilization experiments are conducted in a basin-scale, eddy-permitting coupled physical biogeochemical ecological model. In contrast to previous studies, we find that most of the dissolved inorganic carbon (DIC) removed from the euphotic zone by the enhanced biological export is replaced by uptake of CO2 from the atmosphere. Atmospheric uptake efficiencies, the ratio of the perturbation in air-sea CO2 flux to the perturbation in export flux across 100 m, are 0.75 to 0.93 in our patch size-scale experiments. The atmospheric uptake efficiency is insensitive to the duration of the experiment. The primary factor controlling the atmospheric uptake efficiency is the vertical distribution of the enhanced biological production. Iron fertilization at the surface tends to induce production anomalies primarily near the surface, leading to high efficiencies. In contrast, mechanisms that induce deep production anomalies (e.g. altered light availability) tend to have a low uptake efficiency, since most of the removed DIC is replaced by lateral and vertical transport and mixing. Despite high atmospheric uptake efficiencies, patch-scale iron fertilization of the ocean's biological pump tends to remove little CO2 from the atmosphere over the decadal timescale considered here.

Multidrug resistance: prospects for clinical management.

PubMed

Mansouri, A; Henle, K J; Nagle, W A

1992-01-01

Clinical success in the treatment of tumors with chemotherapy has significantly improved over the past several years. However, treatment failures due to drug resistance of cancer cells has remained a major problem. The classical form of multiple drug resistance is perhaps also the most common type of drug resistance, and represents the overexpression of a transmembrane glycoprotein pump (P-170) that mediates the efflux of a spectrum of structurally and functionally unrelated drugs. Here, we discuss recent evidence that support the concept that the total phenomenon of multiple drug resistance (MDR) involves several other mechanisms in addition to that underlying "classical" MDR. These include the action of other energy-dependent membrane efflux pumps, elevated levels of GSH for drug conjugation and detoxification to facilitate export, enhanced DNA repair facility, gene amplification and oncogene activation. The combination of mechanisms used by any particular cell line is variable and suggests that many of these mechanisms are independent. Successful reversal of drug resistance appears to require the identification of relevant operative resistance mechanisms. An example is the competitive inhibition of P-170 with verapamil, quinine and tamoxifen. A broadly successful strategy for killing drug-resistant cancer cells, however, could be based on either selective energy depletion of cancer cells or the permeabilization of tumor cells with an effective bypass of efflux pumps, since many mechanisms of drug resistance entail the energy-dependent export of toxins. The latter approach may be achieved via membrane lipid modifications or the introduction of membrane pores by biological or physical (electroporation) means.

Effects of Monovalent and Divalent Salt Solutions on the Transport of Toxoplasma gondii in Saturated Porous Media

NASA Astrophysics Data System (ADS)

Darnault, C. J. G.; Pullano, C. P.; Mutty, T.; L'Ollivier, C.; Dubey, J. P.; Dumetre, A.

2017-12-01

The pathogenic microorganism Toxoplasma gondii is a current public health threat. Knowledge of the fate and transport of T. gondii in the environment, especially the subsurface, is critical to evaluate the risk of soil and groundwater contaminations. The physico-chemcial properties of groundwater systems, i.e. solution chemistry and aquifer materials, play a key role in the interaction of biocolloids with surfaces and therefore their mobility. This research examines how different salt solutions alter the mobility of T. gondii through saturated porous media. Salt solutions containing varying ionic strengths and concentrations of sodium chloride, calcium chloride, and magnesium chloride were used to test the transport of the T. gondii oocysts. These tests were performed using quartz silica sand columns fed by a peristaltic pump in order to generate flow and transport of the biocolloids. The salt solution was pumped though the column followed by a pulse of the T. gondii oocysts, then a pulse of salt solution without oocysts, and then lastly a pulse of distilled water. Sampling of the solution exiting the columns was tested for T. gondii oocysts using qPCR in order to quantify the oocysts present. The breakthough curve results were then compared to a conservative bromide tracer test in order to determine the factors associated with the movement of these biocolloids through the sand columns. A model of the flow of the toxoplasma colloids through the sand matrix was made in order to characterize the parameters affecting the transport and retention of T. gondii occysts though saturated porous media.

NOKOMIS 3-F4

EPA Pesticide Factsheets

Technical product bulletin: this dispersant used in oil spill cleanups may be applied directly from drums by fitting them with a T connection and pumping fresh or salt water across the junction, which pulls dispersant into water stream and onto spill.

Genesis and shape of natural solution cavities within salt deposits

NASA Astrophysics Data System (ADS)

Gechter, Daniel; Huggenberger, Peter; Ackerer, Philippe; Waber, H. Niklaus

2008-11-01

Since the genesis and shape of natural deep-seated cavities within a salt body are insufficiently understood, the current study tries to shed some light on this topic. To this end, freshwater was pumped slowly through a horizontal borehole in rock salt cores. Owing to fast halite dissolution kinetics, high solubility, and slow inflow rate, halite dissolution took place only in the inflow of the rock salt cylinder. The shape of the created cavities is an approximately symmetrical half cone with a horizontal base facing upward. A conceptual model is presented that is inspired by the experimental results and based on theoretical hydraulic-geochemical considerations, as well as on field observations. It proposes that triangular prism or conically shaped cavities develop within salt under confined conditions, where aggressive water flows upward along a fracture/conduit from an insoluble aquifer into the soluble stratum. Such cavity enlargements may cause land subsidence and structure collapse.

Regulation of Na+ and K+ homeostasis in plants: towards improved salt stress tolerance in crop plants

PubMed Central

Almeida, Diego M.; Oliveira, M. Margarida; Saibo, Nelson J. M.

2017-01-01

Abstract Soil salinity is a major abiotic stress that results in considerable crop yield losses worldwide. However, some plant genotypes show a high tolerance to soil salinity, as they manage to maintain a high K+/Na+ ratio in the cytosol, in contrast to salt stress susceptible genotypes. Although, different plant genotypes show different salt tolerance mechanisms, they all rely on the regulation and function of K+ and Na+ transporters and H+ pumps, which generate the driving force for K+ and Na+ transport. In this review we will introduce salt stress responses in plants and summarize the current knowledge about the most important ion transporters that facilitate intra- and intercellular K+ and Na+ homeostasis in these organisms. We will describe and discuss the regulation and function of the H+-ATPases, H+-PPases, SOS1, HKTs, and NHXs, including the specific tissues where they work and their response to salt stress. PMID:28350038

Community solar salt production in Goa, India

PubMed Central

2012-01-01

Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa’s riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans. Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1–2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested. Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced. The aim of this review is to describe salt farming in Goa’s history, importance of salt production as a community activity, traditional method of salt production and the biota associated with salt pans. PMID:23198813

Community solar salt production in Goa, India.

PubMed

Mani, Kabilan; Salgaonkar, Bhakti B; Das, Deepthi; Bragança, Judith M

2012-12-01

Traditional salt farming in Goa, India has been practised for the past 1,500 years by a few communities. Goa's riverine estuaries, easy access to sea water and favourable climatic conditions makes salt production attractive during summer. Salt produced through this natural evaporation process also played an important role in the economy of Goa even during the Portuguese rule as salt was the chief export commodity. In the past there were 36 villages involved in salt production, which is now reduced to 9. Low income, lack of skilled labour, competition from industrially produced salt, losses incurred on the yearly damage of embankments are the major reasons responsible for the reduction in the number of salt pans.Salt pans (Mithagar or Mithache agor) form a part of the reclaimed waterlogged khazan lands, which are also utilised for aquaculture, pisciculture and agriculture. Salt pans in Goa experience three phases namely, the ceased phase during monsoon period of June to October, preparatory phase from December to January, and salt harvesting phase, from February to June. After the monsoons, the salt pans are prepared manually for salt production. During high tide, an influx of sea water occurs, which enters the reservoir pans through sluice gates. The sea water after 1-2 days on attaining a salinity of approximately 5ºBé, is released into the evaporator pans and kept till it attains a salinity of 23 - 25ºBé. The brine is then released to crystallizer pans, where the salt crystallises out 25 - 27ºBé and is then harvested.Salt pans form a unique ecosystem where succession of different organisms with varying environmental conditions occurs. Organisms ranging from bacteria, archaea to fungi, algae, etc., are known to colonise salt pans and may influence the quality of salt produced.The aim of this review is to describe salt farming in Goa's history, importance of salt production as a community activity, traditional method of salt production and the biota associated with salt pans.

A Benzimidazole Proton Pump Inhibitor Increases Growth and Tolerance to Salt Stress in Tomato.

PubMed

Van Oosten, Michael J; Silletti, Silvia; Guida, Gianpiero; Cirillo, Valerio; Di Stasio, Emilio; Carillo, Petronia; Woodrow, Pasqualina; Maggio, Albino; Raimondi, Giampaolo

2017-01-01

Pre-treatment of tomato plants with micromolar concentrations of omeprazole (OP), a benzimidazole proton pump inhibitor in mammalian systems, improves plant growth in terms of fresh weight of shoot and roots by 49 and 55% and dry weight by 54 and 105% under salt stress conditions (200 mM NaCl), respectively. Assessment of gas exchange, ion distribution, and gene expression profile in different organs strongly indicates that OP interferes with key components of the stress adaptation machinery, including hormonal control of root development (improving length and branching), protection of the photosynthetic system (improving quantum yield of photosystem II) and regulation of ion homeostasis (improving the K + :Na + ratio in leaves and roots). To our knowledge OP is one of the few known molecules that at micromolar concentrations manifests a dual function as growth enhancer and salt stress protectant. Therefore, OP can be used as new inducer of stress tolerance to better understand molecular and physiological stress adaptation paths in plants and to design new products to improve crop performance under suboptimal growth conditions. Highlight: Omeprazole enhances growth of tomato and increases tolerance to salinity stress through alterations of gene expression and ion uptake and transport.

A Benzimidazole Proton Pump Inhibitor Increases Growth and Tolerance to Salt Stress in Tomato

PubMed Central

Van Oosten, Michael J.; Silletti, Silvia; Guida, Gianpiero; Cirillo, Valerio; Di Stasio, Emilio; Carillo, Petronia; Woodrow, Pasqualina; Maggio, Albino; Raimondi, Giampaolo

2017-01-01

Pre-treatment of tomato plants with micromolar concentrations of omeprazole (OP), a benzimidazole proton pump inhibitor in mammalian systems, improves plant growth in terms of fresh weight of shoot and roots by 49 and 55% and dry weight by 54 and 105% under salt stress conditions (200 mM NaCl), respectively. Assessment of gas exchange, ion distribution, and gene expression profile in different organs strongly indicates that OP interferes with key components of the stress adaptation machinery, including hormonal control of root development (improving length and branching), protection of the photosynthetic system (improving quantum yield of photosystem II) and regulation of ion homeostasis (improving the K+:Na+ ratio in leaves and roots). To our knowledge OP is one of the few known molecules that at micromolar concentrations manifests a dual function as growth enhancer and salt stress protectant. Therefore, OP can be used as new inducer of stress tolerance to better understand molecular and physiological stress adaptation paths in plants and to design new products to improve crop performance under suboptimal growth conditions. Highlight: Omeprazole enhances growth of tomato and increases tolerance to salinity stress through alterations of gene expression and ion uptake and transport. PMID:28769943

Role of Vasopressin in Rat Models of Salt-Dependent Hypertension.

PubMed

Prager-Khoutorsky, Masha; Choe, Katrina Y; Levi, David I; Bourque, Charles W

2017-05-01

Dietary salt intake increases both plasma sodium and osmolality and therefore increases vasopressin (VP) release from the neurohypophysis. Although this effect could increase blood pressure by inducing fluid reabsorption and vasoconstriction, acute activation of arterial baroreceptors inhibits VP neurons via GABA A receptors to oppose high blood pressure. Here we review recent findings demonstrating that this protective mechanism fails during chronic high salt intake in rats. Two recent studies showed that chronic high sodium intake causes an increase in intracellular chloride concentration in VP neurons. This effect causes GABA A receptors to become excitatory and leads to the emergence of VP-dependent hypertension. One study showed that the increase in intracellular chloride was provoked by a decrease in the expression of the chloride exporter KCC2 mediated by local secretion of brain-derived neurotrophic factor and activation of TrkB receptors. Prolonged high dietary salt intake can cause pathological plasticity in a central homeostatic circuit that controls VP secretion and thereby contribute to peripheral vasoconstriction and hypertension.

Tracer adsorption in sand-tank experiments of saltwater up-coning

NASA Astrophysics Data System (ADS)

Jakovovic, Danica; Post, Vincent E. A.; Werner, Adrian D.; Männicke, Oliver; Hutson, John L.; Simmons, Craig T.

2012-01-01

SummaryThis study aims to substantiate otherwise unresolved double-peaked plumes produced in recent saltwater up-coning experiments (see Jakovovic et al. (2011), Numerical modelling of saltwater up-coning: Comparison with experimental laboratory observations, Journal of Hydrology 402, 261-273) through additional laboratory testing and numerical modelling. Laboratory experimentation successfully reproduced the double-peaked plume demonstrating that this phenomenon was not an experimental nuance in previous experiments. Numerical modelling by Jakovovic et al. (2011) was extended by considering adsorption effects, which were needed to explain the observed up-coning double peaks of both previous and current laboratory experiments. A linear adsorption isotherm was applied in predicting dye tracer (Rhodamine WT) behaviour in the sand-tank experiments using adsorption parameters obtained experimentally. The same adsorption parameters were tested on all laboratory experiments and it was found that adsorption had insignificant effect on experiments with high pumping rates. However, low pumping rates produced pronounced spatial velocity variations within the dense salt plume beneath the pumping well, with velocities within the plume increasing from the centre of the plume towards the interface. The dye tracer was retarded relative to the salt and was transported preferentially along the higher-velocity paths (i.e. along the edges of the salt plume) towards the well forming double-peaked up-coning patterns. This illustrates the sensitive adsorptive nature of Rhodamine WT and that care should be taken when it is used in similar sand-tank experiments. Observations from this study offer insight into the separation of chemicals in natural systems due to different adsorption characteristics and under conditions of density-dependent flow.

10 CFR Appendix K to Part 110 - Illustrative List of Equipment and Components Under NRC Export Licensing Authority for Use in a...

Code of Federal Regulations, 2014 CFR

2014-01-01

... from synthesis gas through contact with liquid ammonia in the presence of a catalyst. The systhesis gas... contactors which promote intimate gas/liquid contact. Stage pumps include especially designed submersible... down the towers while the hydrogen sulphide gas circulates from the bottom to the top of the towers. A...

10 CFR Appendix K to Part 110 - Illustrative List of Equipment and Components Under NRC Export Licensing Authority for Use in a...

Code of Federal Regulations, 2012 CFR

2012-01-01

... from synthesis gas through contact with liquid ammonia in the presence of a catalyst. The systhesis gas... contactors which promote intimate gas/liquid contact. Stage pumps include especially designed submersible... down the towers while the hydrogen sulphide gas circulates from the bottom to the top of the towers. A...

10 CFR Appendix K to Part 110 - Illustrative List of Equipment and Components Under NRC Export Licensing Authority for Use in a...

Code of Federal Regulations, 2013 CFR

2013-01-01

... from synthesis gas through contact with liquid ammonia in the presence of a catalyst. The systhesis gas... contactors which promote intimate gas/liquid contact. Stage pumps include especially designed submersible... down the towers while the hydrogen sulphide gas circulates from the bottom to the top of the towers. A...

10 CFR Appendix K to Part 110 - Illustrative List of Equipment and Components Under NRC Export Licensing Authority for Use in a...

Code of Federal Regulations, 2011 CFR

2011-01-01

... from synthesis gas through contact with liquid ammonia in the presence of a catalyst. The systhesis gas... contactors which promote intimate gas/liquid contact. Stage pumps include especially designed submersible... down the towers while the hydrogen sulphide gas circulates from the bottom to the top of the towers. A...

10 CFR Appendix K to Part 110 - Illustrative List of Equipment and Components Under NRC Export Licensing Authority for Use in a...

Code of Federal Regulations, 2010 CFR

2010-01-01

... from synthesis gas through contact with liquid ammonia in the presence of a catalyst. The systhesis gas... contactors which promote intimate gas/liquid contact. Stage pumps include especially designed submersible... down the towers while the hydrogen sulphide gas circulates from the bottom to the top of the towers. A...

The role of diatom resting spores in pelagic-benthic coupling in the Southern Ocean

NASA Astrophysics Data System (ADS)

Rembauville, Mathieu; Blain, Stéphane; Manno, Clara; Tarling, Geraint; Thompson, Anu; Wolff, George; Salter, Ian

2018-05-01

Natural iron fertilization downstream of Southern Ocean island plateaus supports large phytoplankton blooms and promotes carbon export from the mixed layer. In addition to sequestering atmospheric CO2, the biological carbon pump also supplies organic matter (OM) to deep-ocean ecosystems. Although the total flux of OM arriving at the seafloor sets the energy input to the system, the chemical nature of OM is also of significance. However, a quantitative framework linking ecological flux vectors to OM composition is currently lacking. In the present study we report the lipid composition of export fluxes collected by five moored sediment traps deployed in contrasting productivity regimes of Southern Ocean island systems (Kerguelen, Crozet and South Georgia) and compile them with quantitative data on diatom and faecal pellet fluxes. At the three naturally iron-fertilized sites, the relative contribution of labile lipids (mono- and polyunsaturated fatty acids, unsaturated fatty alcohols) is 2-4 times higher than at low productivity sites. There is a strong attenuation of labile components as a function of depth, irrespective of productivity. The three island systems also display regional characteristics in lipid export. An enrichment of zooplankton dietary sterols, such as C27Δ5, at South Georgia is consistent with high zooplankton and krill biomass in the region and the importance of faecal pellets to particulate organic carbon (POC) flux. There is a strong association of diatom resting spore fluxes that dominate productive flux regimes with energy-rich unsaturated fatty acids. At the Kerguelen Plateau we provide a statistical framework to link seasonal variation in ecological flux vectors and lipid composition over a complete annual cycle. Our analyses demonstrate that ecological processes in the upper ocean, e.g. resting spore formation and grazing, not only impact the magnitude and stoichiometry of the Southern Ocean biological pump, but also regulate the composition of exported OM and the nature of pelagic-benthic coupling.

Influence of top-down control in the plankton food web on vertical carbon flux: a mesocosm study in the Chesapeake Bay

NASA Astrophysics Data System (ADS)

Stone, J.; Steinberg, D. K.

2016-02-01

The effects of predation on carbon export in planktonic food webs are poorly known, but likely play a key role in the biological pump. Gelatinous zooplankton (GZ) dominate the zooplankton community in the Chesapeake Bay during summer months, exerting considerable top-down control on the planktonic food web. The medusa Chrysaora quinquecirrha preys upon the ctenophore Mnemiopsis leidyi, which in turn is a major predator of the omnivorous copepod Acartia tonsa. This trophic cascade is known to significantly affect copepod abundance in Chesapeake Bay, but the resulting changes to particulate organic carbon (POC) flux are unknown. We hypothesized that additions or exclusions of GZ predators would result in changes in both total POC flux and the composition of exported particles (e.g., phytoplankton aggregates, fecal pellets). We conducted mesocosm experiments in the York River tributary of Chesapeake Bay during summer and fall, 2015 to quantify the cascading effects of GZ blooms on POC flux. The mesocosms contained a natural assemblage of phytoplankton and microzooplankton, and A. tonsa copepods, and received one of four treatments of GZ: 1) a control with no GZ added, 2) addition of ctenophores, 3) addition of medusae, and 4) addition of both ctenophores and medusae. POC flux from each mesocosm was measured over multiple 2-day experimental runs and grazing rates of GZ on each other and on copepods were calculated. There were no significant differences in total POC flux between treatments, but the composition of both the final zooplankton assemblage and exported organic matter differed between treatments. As a result of grazing on copepods by ctenophores, treatments which included GZ had lower final copepod abundances and a corresponding decrease in flux of copepod fecal pellets. We discuss how this change in composition of exported material as a result of cascading trophic interactions may affect the efficiency of the biological pump and benthic processes.

The WSTIAC Quarterly. Volume 9, Number 3

DTIC Science & Technology

2010-01-25

program .[8] THE THORIUM FUEL CYCLE AND LFTR POWER PLANT The thorium fuel cycle is based on a series of neutron absorp- tion and beta decay processes...the fig- ure is a graphite matrix moderated MSR reactor with fuel salt mixture (ThF4-U233F4) being circulated by a pump through the core and to a...the core as purified salt. As one of the unique safety features, a melt-plug at the reactor bottom would permit the reactor fluid fuel to be drained

Evaluation of Friction Stir Processing of HY-80 Steel Under Wet and Dry Conditions

DTIC Science & Technology

2012-03-01

MS80. The tool design included a convex scroll shoulder with a step-spiral protruding pin (CS4). Figure 4. PCBN FSW/P threaded tool. 12 For...and cooling water was pumped through during the FSW/P process, Figure 7. Sea salt was added to distilled water to create a 3.5% salt content. 14... Vacuum hot extraction was used to determine the hydrogen concentration as specified by ASTM E 146–83. In addition, combustion infrared detection

Effect of winds and waves on salt intrusion in the Pearl River estuary

NASA Astrophysics Data System (ADS)

Gong, Wenping; Lin, Zhongyuan; Chen, Yunzhen; Chen, Zhaoyun; Zhang, Heng

2018-02-01

Salt intrusion in the Pearl River estuary (PRE) is a dynamic process that is influenced by a range of factors and to date, few studies have examined the effects of winds and waves on salt intrusion in the PRE. We investigate these effects using the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system applied to the PRE. After careful validation, the model is used for a series of diagnostic simulations. It is revealed that the local wind considerably strengthens the salt intrusion by lowering the water level in the eastern part of the estuary and increasing the bottom landward flow. The remote wind increases the water mixing on the continental shelf, elevates the water level on the shelf and in the PRE and pumps saltier shelf water into the estuary by Ekman transport. Enhancement of the salt intrusion is comparable between the remote and local winds. Waves decrease the salt intrusion by increasing the water mixing. Sensitivity analysis shows that the axial down-estuary wind, is most efficient in driving increases in salt intrusion via wind straining effect.

Challenges in realizing a self-contained hydraulically-driven contractile fiber actuator.

PubMed

Smela, Elisabeth

2017-07-01

The field of soft robots would benefit from electrically controlled contractile actuators in the form of fibers that achieve a strain of 20% in less than a second while exerting high force. This work explores possible designs for achieving this goal using self-contained electroosmotic fluid pumping within a tube-shaped structure. The most promising configuration is a combination of a bellows and a McKibben-type muscle, since pumping fluid from the former to the latter results in contraction of both portions. Realizing such a device entails challenges in fabrication and electrokinetic fluid pumping in closed systems. Further studies of electroosmotic flow in salt-free organic solvents are needed.

Safe intravenous administration in pediatrics: A 5-year Pediatric Intensive Care Unit experience with smart pumps.

PubMed

Manrique-Rodríguez, S; Sánchez-Galindo, A C; Fernández-Llamazares, C M; Calvo-Calvo, M M; Carrillo-Álvarez, Á; Sanjurjo-Sáez, M

2016-10-01

To estimate the impact of smart pump implementation in a pediatric intensive care unit in terms of number and type of administration errors intercepted. Observational, prospective study carried out from January 2010 to March 2015 with syringe and great volumen infusion pumps available in the hospital. A tertiary level hospital pediatric intensive care unit. Infusions delivered with infusion pumps in all pediatric intensive care unit patients. Design of a drug library with safety limits for all intravenous drugs prescribed. Users' compliance with drug library as well as number and type of errors prevented were analyzed. Two hundred and eighty-three errors were intercepted during 62 months of study. A high risk drug was involved in 58% of prevented errors, such as adrenergic agonists and antagonists, sedatives, analgesics, neuromuscular blockers, opioids, potassium and insulin. Users' average compliance with the safety software was 84%. Smart pumps implementation has proven effective in intercepting high risk drugs programming errors. These results might be exportable to other critical care units, involving pediatric or adult patients. Interdisciplinary colaboration is key to succeed in this process. Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

Biological and physical controls in the Southern Ocean on past millennial-scale atmospheric CO2 changes.

PubMed

Gottschalk, Julia; Skinner, Luke C; Lippold, Jörg; Vogel, Hendrik; Frank, Norbert; Jaccard, Samuel L; Waelbroeck, Claire

2016-05-17

Millennial-scale climate changes during the last glacial period and deglaciation were accompanied by rapid changes in atmospheric CO2 that remain unexplained. While the role of the Southern Ocean as a 'control valve' on ocean-atmosphere CO2 exchange has been emphasized, the exact nature of this role, in particular the relative contributions of physical (for example, ocean dynamics and air-sea gas exchange) versus biological processes (for example, export productivity), remains poorly constrained. Here we combine reconstructions of bottom-water [O2], export production and (14)C ventilation ages in the sub-Antarctic Atlantic, and show that atmospheric CO2 pulses during the last glacial- and deglacial periods were consistently accompanied by decreases in the biological export of carbon and increases in deep-ocean ventilation via southern-sourced water masses. These findings demonstrate how the Southern Ocean's 'organic carbon pump' has exerted a tight control on atmospheric CO2, and thus global climate, specifically via a synergy of both physical and biological processes.

Biological and physical controls in the Southern Ocean on past millennial-scale atmospheric CO2 changes

PubMed Central

Gottschalk, Julia; Skinner, Luke C.; Lippold, Jörg; Vogel, Hendrik; Frank, Norbert; Jaccard, Samuel L.; Waelbroeck, Claire

2016-01-01

Millennial-scale climate changes during the last glacial period and deglaciation were accompanied by rapid changes in atmospheric CO2 that remain unexplained. While the role of the Southern Ocean as a 'control valve' on ocean–atmosphere CO2 exchange has been emphasized, the exact nature of this role, in particular the relative contributions of physical (for example, ocean dynamics and air–sea gas exchange) versus biological processes (for example, export productivity), remains poorly constrained. Here we combine reconstructions of bottom-water [O2], export production and 14C ventilation ages in the sub-Antarctic Atlantic, and show that atmospheric CO2 pulses during the last glacial- and deglacial periods were consistently accompanied by decreases in the biological export of carbon and increases in deep-ocean ventilation via southern-sourced water masses. These findings demonstrate how the Southern Ocean's 'organic carbon pump' has exerted a tight control on atmospheric CO2, and thus global climate, specifically via a synergy of both physical and biological processes. PMID:27187527

Schedules of controlled substances: temporary placement of three synthetic cannabinoids into Schedule I. Final order.

PubMed

2013-05-16

The Deputy Administrator of the Drug Enforcement Administration (DEA) is issuing this final order to temporarily schedule three synthetic cannabinoids under the Controlled Substances Act (CSA) pursuant to the temporary scheduling provisions of 21 U.S.C. 811(h). The substances are (1-pentyl-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone (UR-144), [1-(5-fluoro-pentyl)-1H-indol-3-yl](2,2,3,3-tetramethylcyclopropyl)methanone (5-fluoro-UR-144, XLR11) and N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (APINACA, AKB48). This action is based on a finding by the Deputy Administrator that the placement of these synthetic cannabinoids and their salts, isomers and salts of isomers into Schedule I of the CSA is necessary to avoid an imminent hazard to the public safety. As a result of this order, the full effect of the CSA and the Controlled Substances Import and Export Act (CSIEA) and their implementing regulations including criminal, civil and administrative penalties, sanctions and regulatory controls of Schedule I substances will be imposed on the manufacture, distribution, possession, importation, and exportation of these synthetic cannabinoids.

Hepatic 3D spheroid models for the detection and study of compounds with cholestatic liability

PubMed Central

Hendriks, Delilah F. G.; Fredriksson Puigvert, Lisa; Messner, Simon; Mortiz, Wolfgang; Ingelman-Sundberg, Magnus

2016-01-01

Drug-induced cholestasis (DIC) is poorly understood and its preclinical prediction is mainly limited to assessing the compound’s potential to inhibit the bile salt export pump (BSEP). Here, we evaluated two 3D spheroid models, one from primary human hepatocytes (PHH) and one from HepaRG cells, for the detection of compounds with cholestatic liability. By repeatedly co-exposing both models to a set of compounds with different mechanisms of hepatotoxicity and a non-toxic concentrated bile acid (BA) mixture for 8 days we observed a selective synergistic toxicity of compounds known to cause cholestatic or mixed cholestatic/hepatocellular toxicity and the BA mixture compared to exposure to the compounds alone, a phenomenon that was more pronounced after extending the exposure time to 14 days. In contrast, no such synergism was observed after both 8 and 14 days of exposure to the BA mixture for compounds that cause non-cholestatic hepatotoxicity. Mechanisms behind the toxicity of the cholestatic compound chlorpromazine were accurately detected in both spheroid models, including intracellular BA accumulation, inhibition of ABCB11 expression and disruption of the F-actin cytoskeleton. Furthermore, the observed synergistic toxicity of chlorpromazine and BA was associated with increased oxidative stress and modulation of death receptor signalling. Combined, our results demonstrate that the hepatic spheroid models presented here can be used to detect and study compounds with cholestatic liability. PMID:27759057

Pinelliae Rhizoma Praeparatum Involved in the Regulation of Bile Acids Metabolism in Hepatic Injury.

PubMed

Guo, Shun; Zhang, Song; Liu, Linna; Yang, Peng; Dang, Xueliang; Wei, Huamei; Hu, Na; Shi, Lei; Zhang, Yan

2018-06-01

Pinelliae Rhizoma Praeparatum (PRP) as traditional Chinese medicine had been used for hepatic diseases in combinative forms. However, the effect of PRP was not clear when used alone. So to explore the hepatoprotective/hepatotoxin of PRP is necessary. The activities of PRP were investigated in acetaminophen-induced hepatic injury mice. Liver function markers, hepatic oxidative stress markers were evaluated. Bile acids metabolic transports and nuclear factor erythroid 2-related factor 2 (Nrf2) were detected. As a drug for the treatment of liver diseases, PRP slightly restored the parameters towards normal in model mice only in low dosage, and also had no antioxidant activity and regulate Nrf2. Cholestasis was significantly elevated in model mice when pretreatment with routine or high dosage of PRP, but had no effect on normal mice. Bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2) in model mice were markedly increased when pretreatment with low dose PRP, but significantly decreased when pretreatment in routine or high dosage. Mrp3 was significantly induced in model mice after pretreatment of PRP. But the adjustment effect to bile acids transporters by PRP was not significant in normal mice. These results reveal that PRP has the different effects on bile acids transporter in hepatic injury mice, and therefore, the dosage of PRP need to be paid attention to when it is used in clinical hepatic injury.

Minimizing DILI risk in drug discovery - A screening tool for drug candidates.

PubMed

Schadt, S; Simon, S; Kustermann, S; Boess, F; McGinnis, C; Brink, A; Lieven, R; Fowler, S; Youdim, K; Ullah, M; Marschmann, M; Zihlmann, C; Siegrist, Y M; Cascais, A C; Di Lenarda, E; Durr, E; Schaub, N; Ang, X; Starke, V; Singer, T; Alvarez-Sanchez, R; Roth, A B; Schuler, F; Funk, C

2015-12-25

Drug-induced liver injury (DILI) is a leading cause of acute hepatic failure and a major reason for market withdrawal of drugs. Idiosyncratic DILI is multifactorial, with unclear dose-dependency and poor predictability since the underlying patient-related susceptibilities are not sufficiently understood. Because of these limitations, a pharmaceutical research option would be to reduce the compound-related risk factors in the drug-discovery process. Here we describe the development and validation of a methodology for the assessment of DILI risk of drug candidates. As a training set, 81 marketed or withdrawn compounds with differing DILI rates - according to the FDA categorization - were tested in a combination of assays covering different mechanisms and endpoints contributing to human DILI. These include the generation of reactive metabolites (CYP3A4 time-dependent inhibition and glutathione adduct formation), inhibition of the human bile salt export pump (BSEP), mitochondrial toxicity and cytotoxicity (fibroblasts and human hepatocytes). Different approaches for dose- and exposure-based calibrations were assessed and the same parameters applied to a test set of 39 different compounds. We achieved a similar performance to the training set with an overall accuracy of 79% correctly predicted, a sensitivity of 76% and a specificity of 82%. This test system may be applied in a prospective manner to reduce the risk of idiosyncratic DILI of drug candidates. Copyright © 2015 Elsevier B.V. All rights reserved.

Beyond Reasonable Doubt: Who Is the Culprit in Lipotoxicity in NAFLD/NASH?

PubMed Central

Arteel, Gavin E.

2016-01-01

BACKGROUND & AIMS Type 2 diabetes and nonalcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to the pathogenesis of NASH. METHODS Alms1 mutant (foz/foz) and wild-type NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice. RESULTS Hepatic cholesterol accumulation was attributed to up-regulation of low-density lipoprotein receptor via activation of sterol regulatory element binding protein 2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and low-density lipoprotein receptor and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol levels exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis. CONCLUSIONS In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH. PMID:22422583

Hepatic free cholesterol accumulates in obese, diabetic mice and causes nonalcoholic steatohepatitis.

PubMed

Van Rooyen, Derrick M; Larter, Claire Z; Haigh, W Geoffrey; Yeh, Matthew M; Ioannou, George; Kuver, Rahul; Lee, Sum P; Teoh, Narci C; Farrell, Geoffrey C

2011-10-01

Type 2 diabetes and nonalcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to the pathogenesis of NASH. Alms1 mutant (foz/foz) and wild-type NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice. Hepatic cholesterol accumulation was attributed to up-regulation of low-density lipoprotein receptor via activation of sterol regulatory element binding protein 2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and low-density lipoprotein receptor and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol levels exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis. In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

Hepatic Free Cholesterol Accumulates in Obese, Diabetic Mice and Causes Non-Alcoholic Steatohepatitis

PubMed Central

Van Rooyen, Derrick M; Larter, Claire Z; Haigh, W Geoffrey; Yeh, Matthew M; Ioannou, George; Kuver, Rahul; Lee, Sum P; Teoh, Narci C; Farrell, Geoffrey C

2011-01-01

Background & Aims Type-2 diabetes and non-alcoholic steatohepatitis (NASH) are associated with insulin resistance and disordered cholesterol homeostasis. We investigated the basis for hepatic cholesterol accumulation with insulin resistance and its relevance to pathogenesis of NASH. Methods Alms1 mutant (foz/foz) and wild-type (WT) NOD.B10 mice were fed high-fat diets that contained varying percentages of cholesterol; hepatic lipid pools and pathways of cholesterol turnover were determined. Hepatocytes were exposed to insulin concentrations that circulate in diabetic foz/foz mice. Results Hepatic cholesterol accumulation was attributed to up-regulation of low density lipoprotein receptor (LDLR) via activation of sterol regulatory element binding protein-2 (SREBP-2), reduced biotransformation to bile acids, and suppression of canalicular pathways for cholesterol and bile acid excretion in bile. Exposing primary hepatocytes to concentrations of insulin that circulate in diabetic Alms1 mice replicated the increases in SREBP-2 and LDLR and suppression of bile salt export pump. Removing cholesterol from diet prevented hepatic accumulation of free cholesterol and NASH; increasing dietary cholesterol exacerbated hepatic accumulation of free cholesterol, hepatocyte injury or apoptosis, macrophage recruitment, and liver fibrosis. Conclusions In obese, diabetic mice, hyperinsulinemia alters nuclear transcriptional regulators of cholesterol homeostasis, leading to hepatic accumulation of free cholesterol; the resulting cytotoxicity mediates transition of steatosis to NASH. PMID:21703998

Lipid flopping in the liver.

PubMed

Linton, Kenneth J

2015-10-01

Bile is synthesized in the liver and is essential for the emulsification of dietary lipids and lipid-soluble vitamins. It is a complex mixture of amphiphilic bile acids (BAs; which act as detergent molecules), the membrane phospholipid phosphatidylcholine (PC), cholesterol and a variety of endogenous metabolites and waste products. Over the last 20 years, the combined effort of clinicians, geneticists, physiologists and biochemists has shown that each of these bile components is transported across the canalicular membrane of the hepatocyte by its own specific ATP-binding cassette (ABC) transporter. The bile salt export pump (BSEP) ABCB11 transports the BAs and drives bile flow from the liver, but it is now clear that two lipid transporters, ABCB4 (which flops PC into the bile) and the P-type ATPase ATP8B1/CDC50 (which flips a different phospholipid in the opposite direction) play equally critical roles that protect the biliary tree from the detergent activity of the bile acids. Understanding the interdependency of these lipid floppases and flippases has allowed the development of an assay to measure ABCB4 function. ABCB4 harbours numerous mis-sense mutations which probably reflects the spectrum of liver disease rooted in ABCB4 aetiology. Characterization of the effect of these mutations at the protein level opens the possibility for the development of personalized prognosis and treatment. © 2015 Authors; published by Portland Press Limited.

Feline hepatic biotransformation of diazepam: Differences between cats and dogs.

PubMed

van Beusekom, Cyrina D; van den Heuvel, Jeroen J M W; Koenderink, Jan B; Russel, Frans G M; Schrickx, Johannes A

2015-12-01

In contrast to humans and dogs, diazepam has been reported to induce severe hepatic side effects in cats, particularly after repeated dosing. With the aim to elucidate the mechanisms underlying this apparent sensitivity of cats to drug-induced liver injury, in a series of in vitro experiments, the feline-specific biotransformation of diazepam was studied with liver microsomes obtained from cats and dogs and the possible inhibition of the bile salt export pump (Bsep) was measured in isolated membrane vesicles overexpressing feline and canine Bsep. In line with previous in vivo studies, the phase I metabolites nordiazepam, temazepam and oxazepam were measurable in microsomal incubations, although enzyme velocity of demethylases and hydroxylases differed significantly between cats and dogs. In cats, the main metabolite was temazepam, which also could be glucuronidated. In contrast to dogs, no other glucuronidated metabolites could be observed. In addition, in the membrane vesicles an inhibition of the transport of the Bsep substrate taurocholic acid could be observed in the presence of diazepam and its metabolites. It was concluded that both mechanisms, the slow biotransformation of diazepam as well the inhibition of the bile acid efflux that results in an accumulation of bile acids in the hepatocytes, seem to contribute to the liver injury observed in cats following repetitive treatment with diazepam. Copyright © 2015 Elsevier Ltd. All rights reserved.

Deep Transcriptomic Analysis of Black Rockfish (Sebastes schlegelii) Provides New Insights on Responses to Acute Temperature Stress.

PubMed

Lyu, Likang; Wen, Haishen; Li, Yun; Li, Jifang; Zhao, Ji; Zhang, Simin; Song, Min; Wang, Xiaojie

2018-06-14

In the present study, we conducted an RNA-Seq analysis to characterize the genes and pathways involved in acute thermal and cold stress responses in the liver of black rockfish, a viviparous teleost that has the ability to cope with a wide range of temperature changes. A total of 584 annotated differentially expressed genes (DEGs) were identified in all three comparisons (HT vs NT, HT vs LT and LT vs NT). Based on an enrichment analysis, DEGs with a potential role in stress accommodation were classified into several categories, including protein folding, metabolism, immune response, signal transduction, molecule transport, membrane, and cell proliferation/apoptosis. Considering that thermal stress has a greater effect than cold stress in black rockfish, 24 shared DEGs in the intersection of the HT vs LT and HT vs NT groups were enriched in 2 oxidation-related gene ontology (GO) terms. Nine important heat-stress-reducing pathways were significantly identified and classified into 3 classes: immune and infectious diseases, organismal immune system and endocrine system. Eight DEGs (early growth response protein 1, bile salt export pump, abcb11, hsp70a, rtp3, 1,25-dihydroxyvitamin d(3) 24-hydroxylase, apoa4, transcription factor jun-b-like and an uncharacterized gene) were observed among all three comparisons, strongly implying their potentially important roles in temperature stress responses.

Pore Pressure and Field stress variation from Salt Water Injection; A case Study from Beaver Lodge Field in Williston Basin

NASA Astrophysics Data System (ADS)

Mohammed, R. A.; Khatibi, S.

2017-12-01

One of the major concerns in producing from oil and gas reservoirs in North American Basins is the disposal of high salinity salt water. It is a misconception that Hydro frack triggers Earthquakes, but due to the high salinity and density of water being pumped to the formation that has pore space of the rock already filled, which is not the case in Hydro-frack or Enhanced Oil Recovery in which fracturing fluid is pumped into empty pore space of rocks in depleted reservoirs. A review on the Bakken history showed that the concerns related to induce seismicity has increased over time due to variations in Pore pressure and In-situ stress that have shown steep changes in the region over the time. In this study, we focused on Pore pressure and field Stress variations in lower Cretaceous Inyan Kara and Mississippian Devonian Bakken, Inyan Kara is the major source for class-II salt-water disposal in the basin. Salt-water disposal is the major cause for induced seismicity. A full field study was done on Beaver Lodge Field, which has many salt-water disposal wells Adjacent to Oil and Gas Wells. We analyzed formation properties, stresses, pore-pressure, and fracture gradient profile in the field and. The constructed Mechanical Earth Model (MEM) revealed changes in pore pressure and stresses over time due to saltwater injection. Well drilled in the past were compared to recently drilled wells, which showed much stress variations. Safe mud weight Window of wells near proximity of injection wells was examined which showed many cases of wellbore instabilities. Results of this study will have tremendous impact in studying environmental issues and the future drilling and Fracking operations.

Natural ocean carbon cycle sensitivity to parameterizations of the recycling in a climate model

NASA Astrophysics Data System (ADS)

Romanou, A.; Romanski, J.; Gregg, W. W.

2014-02-01

Sensitivities of the oceanic biological pump within the GISS (Goddard Institute for Space Studies ) climate modeling system are explored here. Results are presented from twin control simulations of the air-sea CO2 gas exchange using two different ocean models coupled to the same atmosphere. The two ocean models (Russell ocean model and Hybrid Coordinate Ocean Model, HYCOM) use different vertical coordinate systems, and therefore different representations of column physics. Both variants of the GISS climate model are coupled to the same ocean biogeochemistry module (the NASA Ocean Biogeochemistry Model, NOBM), which computes prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2 and the deep ocean carbon transport and storage. In particular, the model differences due to remineralization rate changes are compared to differences attributed to physical processes modeled differently in the two ocean models such as ventilation, mixing, eddy stirring and vertical advection. GISSEH(GISSER) is found to underestimate mixed layer depth compared to observations by about 55% (10%) in the Southern Ocean and overestimate it by about 17% (underestimate by 2%) in the northern high latitudes. Everywhere else in the global ocean, the two models underestimate the surface mixing by about 12-34%, which prevents deep nutrients from reaching the surface and promoting primary production there. Consequently, carbon export is reduced because of reduced production at the surface. Furthermore, carbon export is particularly sensitive to remineralization rate changes in the frontal regions of the subtropical gyres and at the Equator and this sensitivity in the model is much higher than the sensitivity to physical processes such as vertical mixing, vertical advection and mesoscale eddy transport. At depth, GISSER, which has a significant warm bias, remineralizes nutrients and carbon faster thereby producing more nutrients and carbon at depth, which eventually resurfaces with the global thermohaline circulation especially in the Southern Ocean. Because of the reduced primary production and carbon export in GISSEH compared to GISSER, the biological pump efficiency, i.e., the ratio of primary production and carbon export at 75 m, is half in the GISSEH of that in GISSER, The Southern Ocean emerges as a key region where the CO2 flux is as sensitive to biological parameterizations as it is to physical parameterizations. The fidelity of ocean mixing in the Southern Ocean compared to observations is shown to be a good indicator of the magnitude of the biological pump efficiency regardless of physical model choice.

Natural Ocean Carbon Cycle Sensitivity to Parameterizations of the Recycling in a Climate Model

NASA Technical Reports Server (NTRS)

Romanou, A.; Romanski, J.; Gregg, W. W.

2014-01-01

Sensitivities of the oceanic biological pump within the GISS (Goddard Institute for Space Studies ) climate modeling system are explored here. Results are presented from twin control simulations of the air-sea CO2 gas exchange using two different ocean models coupled to the same atmosphere. The two ocean models (Russell ocean model and Hybrid Coordinate Ocean Model, HYCOM) use different vertical coordinate systems, and therefore different representations of column physics. Both variants of the GISS climate model are coupled to the same ocean biogeochemistry module (the NASA Ocean Biogeochemistry Model, NOBM), which computes prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2 and the deep ocean carbon transport and storage. In particular, the model differences due to remineralization rate changes are compared to differences attributed to physical processes modeled differently in the two ocean models such as ventilation, mixing, eddy stirring and vertical advection. GISSEH(GISSER) is found to underestimate mixed layer depth compared to observations by about 55% (10 %) in the Southern Ocean and overestimate it by about 17% (underestimate by 2%) in the northern high latitudes. Everywhere else in the global ocean, the two models underestimate the surface mixing by about 12-34 %, which prevents deep nutrients from reaching the surface and promoting primary production there. Consequently, carbon export is reduced because of reduced production at the surface. Furthermore, carbon export is particularly sensitive to remineralization rate changes in the frontal regions of the subtropical gyres and at the Equator and this sensitivity in the model is much higher than the sensitivity to physical processes such as vertical mixing, vertical advection and mesoscale eddy transport. At depth, GISSER, which has a significant warm bias, remineralizes nutrients and carbon faster thereby producing more nutrients and carbon at depth, which eventually resurfaces with the global thermohaline circulation especially in the Southern Ocean. Because of the reduced primary production and carbon export in GISSEH compared to GISSER, the biological pump efficiency, i.e., the ratio of primary production and carbon export at 75 m, is half in the GISSEH of that in GISSER, The Southern Ocean emerges as a key region where the CO2 flux is as sensitive to biological parameterizations as it is to physical parameterizations. The fidelity of ocean mixing in the Southern Ocean compared to observations is shown to be a good indicator of the magnitude of the biological pump efficiency regardless of physical model choice.

Projected Impact of Climate Change on the Water and Salt Budgets of the Arctic Ocean by a Global Climate Model

NASA Technical Reports Server (NTRS)

Miller, James R.; Russell, Gary L.

1996-01-01

The annual flux of freshwater into the Arctic Ocean by the atmosphere and rivers is balanced by the export of sea ice and oceanic freshwater. Two 150-year simulations of a global climate model are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. Relative to the control, the last 50-year period of the GHG experiment indicates that the total inflow of water from the atmosphere and rivers increases by 10% primarily due to an increase in river discharge, the annual sea-ice export decreases by about half, the oceanic liquid water export increases, salinity decreases, sea-ice cover decreases, and the total mass and sea-surface height of the Arctic Ocean increase. The closed, compact, and multi-phased nature of the hydrologic cycle in the Arctic Ocean makes it an ideal test of water budgets that could be included in model intercomparisons.

Development of electric drive for centrifugal mine pumps in Solikamsk Potassium Mine Group Based on Industrial OMRON Controller

NASA Astrophysics Data System (ADS)

Kostarev, S. N.; Sereda, T. G.; Tatarnikova, N. A.; Kochetova, O. V.

2018-03-01

The electric drive for automation pumping out of filtration waters in the Second Solikamsk Potasssium Mine Group is developed. The emergency situation of flooding of the Mine has been considered in the course of development of the Upper Kama deposits of potash-magnesium salts. The functional scheme of automation of a drive of the pump is developed. The scheme is stipulated with manual and automatic control. To decrease the risk of flooding of mine, it is recommended to establish gauges of both bottom and top level control of a brine and other equipment in the collector of a brine: the gauge of measurementof a level, the gauge of the signal system of a level, the gauge of the pump control, the gauge of the signal system of a level with remote data transmission. For regulation of the charge of sewage, the P-regulator with the executive mechanism is stipulated. The ladder diagram of a pump control is developed to improve the work of centrifugal pumps and to prevent the cases of mines flooding.

TANK 26 EVAPORATOR FEED PUMP TRANSFER ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamburello, D; Si Lee, S; Richard Dimenna, R

2008-09-30

The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics methods to determine the amount of entrained sludge solids pumped out of the tank to the evaporator with the downcomer turned on. The analysis results showed that, for the maximummore » and minimum supernate levels in Tank 26 (252.5 and 72 inches above the sludge layer, respectively), the evaporator feed pump will entrain between 0.05 and 0.1 wt% sludge solids weight fraction into the eductor, respectively. Lower tank liquid levels, with respect to the sludge layer, result in higher amounts of sludge entrainment due to the increased velocity of the plunging jets from the downcomer and evaporator feed pump bypass as well as decreased dissipation depth.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kisner, Roger A; Melin, Alexander M; Burress, Timothy A

The overall project objective is to demonstrate improved reliability and increased performance made possible by deeply embedding instrumentation and controls (I&C) in nuclear power plant components. The project is employing a highly instrumented canned rotor, magnetic bearing, fluoride salt pump as its I&C technology demonstration vehicle. The project s focus is not primarily on pump design, but instead is on methods to deeply embed I&C within a pump system. However, because the I&C is intimately part of the basic millisecond-by-millisecond functioning of the pump, the I&C design cannot proceed in isolation from the other aspects of the pump. The pumpmore » will not function if the characteristics of the I&C are not embedded within the design because the I&C enables performance of the basic function rather than merely monitoring quasi-stable performance. Traditionally, I&C has been incorporated in nuclear power plant (NPP) components after their design is nearly complete; adequate performance was obtained through over-design. This report describes the progress and status of the project and provides a conceptual design overview for the embedded I&C pump.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathur, Anoop

A key technological issue facing the success of future Concentrating Solar Thermal Power (CSP) plants is creating an economical Thermal Energy Storage (TES) system. Current TES systems use either sensible heat in fluids such as oil, or molten salts, or use thermal stratification in a dual-media consisting of a solid and a heat-transfer fluid. However, utilizing the heat of fusion in inorganic molten salt mixtures in addition to sensible heat , as in a Phase change material (PCM)-based TES, can significantly increase the energy density of storage requiring less salt and smaller containers. A major issue that is preventing themore » commercial use of PCM-based TES is that it is difficult to discharge the latent heat stored in the PCM melt. This is because when heat is extracted, the melt solidifies onto the heat exchanger surface decreasing the heat transfer. Even a few millimeters of thickness of solid material on heat transfer surface results in a large drop in heat transfer due to the low thermal conductivity of solid PCM. Thus, to maintain the desired heat rate, the heat exchange area must be large which increases cost. This project demonstrated that the heat transfer coefficient can be increase ten-fold by using forced convection by pumping a hyper-eutectic salt mixture over specially coated heat exchanger tubes. However,only 15% of the latent heat is used against a goal of 40% resulting in a projected cost savings of only 17% against a goal of 30%. Based on the failure mode effect analysis and experience with pumping salt at near freezing point significant care must be used during operation which can increase the operating costs. Therefore, we conclude the savings are marginal to justify using this concept for PCM-TES over a two-tank TES. The report documents the specialty coatings, the composition and morphology of hypereutectic salt mixtures and the results from the experiment conducted with the active heat exchanger along with the lessons learnt during experimentation.« less

Influence of freezing and thawing on the hydration characteristics, quality, and consumer acceptance of whole muscle beef injected with solutions of salt and phosphate.

PubMed

Pietrasik, Z; Janz, J A M

2009-03-01

Effects of salt/phosphate injection level (112% or 125% pump), salt level (0.5% or 1.5% salt), and freezing/thawing on hydration characteristics, quality, and consumer acceptance of beef semitendinosus were investigated. All enhancement treatments decreased shear force by 25-35%, but negatively affected colour. Increased salt concentration yielded lower purge and cooking losses, and higher water holding capacity. The higher injection level reduced water binding properties, however, the loss in functionality with higher water addition was overcome with increased salt content. Freezing and subsequent thawing was generally detrimental to colour and water binding properties and tended to increase shear force. Freezing and subsequent thawing did not affect fluid release in steaks held for 1 day before analysis, but resulted in decreased water retention in samples held for 7 days. Holding vacuum packaged steaks for 7 days generally increased package purge and negatively affected colour parameters, although water binding characteristics were improved. Consumer panel results demonstrated a negative effect on juiciness and tenderness where meat subject to low salt/high injection was frozen then thawed - the low salt level was insufficient to maintain any positive effect of injection treatment. In general, salt/phosphate injection improved product acceptability and increased willingness to purchase.

Bile Salt Homeostasis in Normal and Bsep Gene Knockout Rats with Single and Repeated Doses of Troglitazone.

PubMed

Cheng, Yaofeng; Chen, Shenjue; Freeden, Chris; Chen, Weiqi; Zhang, Yueping; Abraham, Pamela; Nelson, David M; Humphreys, W Griffith; Gan, Jinping; Lai, Yurong

2017-09-01

The interference of bile acid secretion through bile salt export pump (BSEP) inhibition is one of the mechanisms for troglitazone (TGZ)-induced hepatotoxicity. Here, we investigated the impact of single or repeated oral doses of TGZ (200 mg/kg/day, 7 days) on bile acid homoeostasis in wild-type (WT) and Bsep knockout (KO) rats. Following oral doses, plasma exposures of TGZ were not different between WT and KO rats, and were similar on day 1 and day 7. However, plasma exposures of the major metabolite, troglitazone sulfate (TS), in KO rats were 7.6- and 9.3-fold lower than in WT on day 1 and day 7, respectively, due to increased TS biliary excretion. With Bsep KO, the mRNA levels of multidrug resistance-associated protein 2 (Mrp2), Mrp3, Mrp4, Mdr1, breast cancer resistance protein (Bcrp), sodium taurocholate cotransporting polypeptide, small heterodimer partner, and Sult2A1 were significantly altered in KO rats. Following seven daily TGZ treatments, Cyp7A1 was significantly increased in both WT and KO rats. In the vehicle groups, plasma exposures of individual bile acids demonstrated variable changes in KO rats as compared with WT. WT rats dosed with TGZ showed an increase of many bile acid species in plasma on day 1, suggesting the inhibition of Bsep. Conversely, these changes returned to base levels on day 7. In KO rats, alterations of most bile acids were observed after seven doses of TGZ. Collectively, bile acid homeostasis in rats was regulated through bile acid synthesis and transport in response to Bsep deficiency and TGZ inhibition. Additionally, our study is the first to demonstrate that repeated TGZ doses can upregulate Cyp7A1 in rats. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Salt-front movement in the Hudson River estuary, New York—Simulations by one-dimensional flow and solute-transport models

USGS Publications Warehouse

de Vries, M. Peter; Weiss, Lawrence A.

2001-01-01

The Hudson River is being considered for use as a supplemental source of water supply for New York City during droughts. One proposal entails withdrawal of Hudson River water from locations near Newburgh, Chelsea, or Kingston, but the extent to which this could cause the salt front to advance upstream to points where it could adversely affect community water supplies is unknown. The U.S. Geological Survey (USGS) one-dimensional Branch-Network Dynamic Flow model (BRANCH) was used in conjunction with the USGS one-dimensional Branched Lagrangian Solute-Transport Model (BLTM) to simulate the effect of five water-withdrawal scenarios on the salt-front location.The modeled reach contains 132 miles of the lower Hudson River between the Federal Dam at Troy and Hastings-on-Hudson (near New York City). The BRANCH model was calibrated and verified to 19 tidal-cycle discharge measurements made at 11 locations by conventional and acoustic Doppler current-profiler methods. Maximum measured instantaneous tidal flow ranged from 20,000 ft3/s (cubic feet per second) at Albany to 368,000 ft3/s at Tellers Point; daily-mean flow at Green Island near Troy ranged from 3,030 ft3/s to 45,000 ft3/s during the flow measurements. Successive ebb- and flood-flow volumes were measured and compared with computed volumes; daily-mean bias was -1.6 percent (range from -21.0 to +23.7 percent; 13.5 percent mean absolute error). Daily-mean deviation between simulated and measured stage at eight locations (from Bowline Point to Albany) over the 19 tidal-cycle measurements averaged +0.06 ft (range from -0.31 to +0.40 ft; 0.21 ft root mean square error, RMSE). These results indicate that the model can accurately simulate flow in the Hudson River under a wide range of flow, tide, and meteorological conditions.The BLTM was used to simulate chloride transport in the 61-mi reach from Turkey Point to Bowline Point under two seasonal conditions in 1990.one representing spring conditions of high inflow and low salinity (April-June), the other representing typical summer conditions of low inflow and high salinity (July-August). Measured chloride concentrations at Bowline Point were used to drive the BLTM simulations, and data collected at West Point were used for calibration. Mean bias in simulated chloride concentration for the April-June 1990 (high flow) data (observed range from 12 to 201 mg/L [milligrams per liter]; 30 mg/L RMSE) was .16 mg/L, and mean bias for the July-August 1990 (low flow) data (observed range from 31 to 2,000 mg/L; 535 mg/ L RMSE) was +126 mg/L. The salt front (saltwater/ freshwater interface) on the Hudson River was defined as the furthest upstream location where the chloride concentration exceeded 100 mg/L. Data from August 1991 were used to evaluate solute transport between West Point and Poughkeepsie because a chloride concentration of 100 mg/L was not observed at Clinton Point in 1990. The BLTM then was used to simulate chloride concentrations at Chelsea Pump Station and Clinton Point. Regression equations, based on daily mean values of specific conductance measured at West Point, were used to estimate daily mean chloride concentrations at Chelsea Pump Station and Clinton Point for model analysis. Mean biases in BLTM-simulated daily mean chloride concentrations for August 1991 were .38 mg/L at Chelsea Pump Station (range from 189 to 551 mg/L; 103 mg/L RMSE) and .9 mg/L at Clinton Point (range from 53 to 264 mg/L; 62 mg/L RMSE).Hypothetical withdrawals at (1) Newburgh, (2) Chelsea, (3) Chelsea and Newburgh, (4) Chelsea and Kingston, and (5) Kingston and Newburgh, were simulated to compute the effects of withdrawals on salt-front movement. Withdrawals of 300 Mgal/d from any combination of Chelsea or Newburgh could result in upstream movement of the salt front of as much as 1.0 mi, given an initial salt-front location between West Point and Rogers Point. Scenarios that included withdrawals at Kingston caused the greatest upstream salt-front movement. Simulation of a 90-day April-June high-flow period during which discharges at Green Island averaged 25,200 ft3/s indicated that withdrawals of 1,939 Mgal/d (million gallons per day) at Chelsea Pump Station would not measureably increase chloride concentrations at Chelsea Pump Station under normal tidal and meteorological conditions, but withdrawals at twice that rate (3,878 Mgal/d) could increase the chloride concentration at Chelsea Pump Station to 250 mg/L.

National Dam Safety Program. Missouri Power and Light Dam (MO 10065), Mississippi - Salt - Quincy River Basin, Audrain County, Missouri. Phase I Inspection Report.

DTIC Science & Technology

1978-12-01

Audrain Stream : Unnamed Tributary of North Fork of Salt River Date of Inspection: September 29 and 30, 1978 Missouri Power and Light Dam No. Mo.10065...for a power plant, and the reser- voir is also used for recreation. The only operating facility at the darnsite is the pump station adjacent to the...identify due to heavy vegetation. 3. Generally unstable rock wall protecting the up- stream slope. 4. Extensive rodent activity throughout the embankment

Primary aerosol and secondary inorganic aerosol budget over the Mediterranean Basin during 2012 and 2013

NASA Astrophysics Data System (ADS)

Guth, Jonathan; Marécal, Virginie; Josse, Béatrice; Arteta, Joaquim; Hamer, Paul

2018-04-01

In the frame of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx), we analyse the budget of primary aerosols and secondary inorganic aerosols over the Mediterranean Basin during the years 2012 and 2013. To do this, we use two year-long numerical simulations with the chemistry-transport model MOCAGE validated against satellite- and ground-based measurements. The budget is presented on an annual and a monthly basis on a domain covering 29 to 47° N latitude and 10° W to 38° E longitude. The years 2012 and 2013 show similar seasonal variations. The desert dust is the main contributor to the annual aerosol burden in the Mediterranean region with a peak in spring, and sea salt being the second most important contributor. The secondary inorganic aerosols, taken as a whole, contribute a similar level to sea salt. The results show that all of the considered aerosol types, except for sea salt aerosols, experience net export out of our Mediterranean Basin model domain, and thus this area should be considered as a source region for aerosols globally. Our study showed that 11 % of the desert dust, 22.8 to 39.5 % of the carbonaceous aerosols, 35 % of the sulfate and 9 % of the ammonium emitted or produced into the study domain are exported. The main sources of variability for aerosols between 2012 and 2013 are weather-related variations, acting on emissions processes, and the episodic import of aerosols from North American fires. In order to assess the importance of the anthropogenic emissions of the marine and the coastal areas which are central for the economy of the Mediterranean Basin, we made a sensitivity test simulation. This simulation is similar to the reference simulation but with the removal of the international shipping emissions and the anthropogenic emissions over a 50 km wide band inland along the coast. We showed that around 30 % of the emissions of carbonaceous aerosols and 35 to 60 % of the exported carbonaceous aerosols originates from the marine and coastal areas. The formation of 23, 27 and 27 %, respectively of, ammonium, nitrate and sulfate aerosols is due to the emissions within the marine and coastal area.

Receiver System: Lessons Learned from Solar Two

NASA Astrophysics Data System (ADS)

Litwin, R. Z.

2002-03-01

The Boeing Company fabricated the Solar Two receiver as a subcontractor for the Solar Two project. The receiver absorbed sunlight reflected from the heliostat field. A molten-nitrate-salt heat transfer fluid was pumped from a storage tank at grade level, heated from 290 to 565DGC by the receiver mounted on top of a tower, then flowed back down into another storage tank. To make electricity, the hot salt was pumped through a steam generator to produce steam that powered a conventional Rankine steam turbine/generator. This evaluation identifies the most significant Solar Two receiver system lessons learned from the Mechanical Design, Instrumentation and Control, Panel Fabrication, Site Construction, Receiver System Operation, and Management from the perspective of the receiver designer/manufacturer. The lessons learned on the receiver system described here consist of two parts: the Problem and one or more identified Solutions. The appendix summarizes an inspection of the advanced receiver panel developed by Boeing that was installed and operated in the Solar Two receiver.

Receiver System: Lessons Learned From Solar Two

DOE Office of Scientific and Technical Information (OSTI.GOV)

LITWIN, ROBERT Z.; PACHECO, JAMES E.

The Boeing Company fabricated the Solar Two receiver as a subcontractor for the Solar Two project. The receiver absorbed sunlight reflected from the heliostat field. A molten-nitrate-salt heat transfer fluid was pumped from a storage tank at grade level, heated from 290 to 565 C by the receiver mounted on top of a tower, then flowed back down into another storage tank. To make electricity, the hot salt was pumped through a steam generator to produce steam that powered a conventional Rankine steam turbine/generator. This evaluation identifies the most significant Solar Two receiver system lessons learned from the Mechanical Design,more » Instrumentation and Control, Panel Fabrication, Site Construction, Receiver System Operation, and Management from the perspective of the receiver designer/manufacturer. The lessons learned on the receiver system described here consist of two parts: the Problem and one or more identified Solutions. The appendix summarizes an inspection of the advanced receiver panel developed by Boeing that was installed and operated in the Solar Two receiver.« less

Amino acid stable isotope applications to deep-sea corals: A molecular geochemistry approach to reconstructing past ocean conditions

NASA Astrophysics Data System (ADS)

McMahon, K.; McCarthy, M. D.; Guilderson, T. P.; Sherwood, O.; Williams, B.; Larsen, T.; Glynn, D. S.

2017-12-01

Future climate change is predicted to alter ocean productivity, food web dynamics, biogeochemical cycling, and the efficacy of the biological pump. Proteinaceous deep-sea corals act as "living sediment traps," providing long-term, high-resolution records of exported surface ocean production and a window into past changes in ocean condition as a historical context for potential future changes. Here, we present recent work developing the application of compound-specific stable isotope analysis of individual amino acids to proteinaceous deep-sea corals to reconstruct past changes in phytoplankton community composition and biogeochemical cycling. We present new calibrations for molecular isotope comparisons between metabolically active coral polyp tissue and bioarchival proteinaceous skeleton. We then applied these techniques to deep-sea corals from the North Pacific Subtropical Gyre (NPSG) to reconstruct centennial to millennial time scale changes in phytoplankton community composition and biogeochemical cycling as a function of regional climate change. This work suggests that the NPSG has undergone multiple major phytoplankton regime shifts over the last millennium between prokaryotic and eukaryotic phytoplankton communities and associated sources of nitrogen fueling production. The most recent regime, which started around the end of the Little Ice Age and the onset of the Industrial era, is unprecedented in the last 1000 years and resulted in a 30-50% increase in diazotrophic cyanobacteria contribution to export production and an associated 17-27% increase in N2-fixation in the NPSG over last century. By offering the first direct phylogenetic context for long-term shifts in isotopic records of exported particulate organic matter, our data represent a major step forward in understanding the evolution of marine plankton community dynamics, food web architecture, biogeochemical cycling, and the climate feedback loops through the biological pump.

The Southern Ocean biogeochemical divide.

PubMed

Marinov, I; Gnanadesikan, A; Toggweiler, J R; Sarmiento, J L

2006-06-22

Modelling studies have demonstrated that the nutrient and carbon cycles in the Southern Ocean play a central role in setting the air-sea balance of CO(2) and global biological production. Box model studies first pointed out that an increase in nutrient utilization in the high latitudes results in a strong decrease in the atmospheric carbon dioxide partial pressure (pCO2). This early research led to two important ideas: high latitude regions are more important in determining atmospheric pCO2 than low latitudes, despite their much smaller area, and nutrient utilization and atmospheric pCO2 are tightly linked. Subsequent general circulation model simulations show that the Southern Ocean is the most important high latitude region in controlling pre-industrial atmospheric CO(2) because it serves as a lid to a larger volume of the deep ocean. Other studies point out the crucial role of the Southern Ocean in the uptake and storage of anthropogenic carbon dioxide and in controlling global biological production. Here we probe the system to determine whether certain regions of the Southern Ocean are more critical than others for air-sea CO(2) balance and the biological export production, by increasing surface nutrient drawdown in an ocean general circulation model. We demonstrate that atmospheric CO(2) and global biological export production are controlled by different regions of the Southern Ocean. The air-sea balance of carbon dioxide is controlled mainly by the biological pump and circulation in the Antarctic deep-water formation region, whereas global export production is controlled mainly by the biological pump and circulation in the Subantarctic intermediate and mode water formation region. The existence of this biogeochemical divide separating the Antarctic from the Subantarctic suggests that it may be possible for climate change or human intervention to modify one of these without greatly altering the other.

Schedules of Controlled Substances: Placement of UR-144, XLR11, and AKB48 into Schedule I. Final rule.

PubMed

2016-05-11

With the issuance of this final rule, the Drug Enforcement Administration places (1-pentyl-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone (UR-144), [1-(5-fluoro-pentyl)-1H-indol-3-yl](2,2,3,3-tetramethylcyclopropyl)methanone (5-fluoro-UR-144, XLR11), and N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (APINACA, AKB48), including their salts, isomers, and salts of isomers whenever the existence of such salts, isomers, and salts of isomers is possible, into schedule I of the Controlled Substances Act. This scheduling action is pursuant to the Controlled Substances Act which requires that such actions be made on the record after opportunity for a hearing through formal rulemaking. This action imposes the regulatory controls and administrative, civil, and criminal sanctions applicable to schedule I controlled substances on persons who handle (manufacture, distribute, reverse distribute, import, export, engage in research, conduct instructional activities or chemical analysis, or possess), or propose to handle UR-144, XLR11, or AKB48.

Coarse-grained Simulations of Substrate Export through Multidrug Efflux Transporter AcrB

NASA Astrophysics Data System (ADS)

Jewel, Yead; Dutta, Prashanta; Liu, Jin

2017-11-01

The treatment of bacterial infectious diseases hampered by the overexpression of multidrug resistance (MDR) systems. The MDR system actively pumps the antibiotic drugs as well as other toxic compounds out of the cells. During the pumping, AcrB (one of the key MDR components) undergoes a series of large-scale proton/substrate dependent conformational changes. In this work, we implement a hybrid coarse-grained PACE force field that couples the united-atom protein model with the coarse-grained MARTINI water/lipid, to investigate the conformational changes of AcrB. We first develop the substrate force field which is compatible with PACE, then we implement the force field to explore large scale structural changes of AcrB in microsecond simulations. The effects of the substrate and the protonation states of two key residues: Asp407 and Asp408, are investigated. Our results show that the drug export through AcrB is proton as well as substrate dependent. Our simulations explain molecular mechanisms of substrate transport through AcrB complex, as well as provide valuable insights for designing proper antibiotic drugs. Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number R01GM122081.

Evidence for a role in growth and salt resistance of a plasma membrane H+-ATPase in the root endodermis

NASA Technical Reports Server (NTRS)

Vitart, V.; Baxter, I.; Doerner, P.; Harper, J. F.; Evans, M. L. (Principal Investigator)

2001-01-01

The plasma membrane of plant cells is energized by an electrochemical gradient produced by P-type H+-ATPases (proton pumps). These pumps are encoded by at least 12 genes in Arabidopsis. Here we provide evidence that isoform AHA4 contributes to solute transport through the root endodermis. AHA4 is expressed most strongly in the root endodermis and flowers, as suggested by promoter-GUS reporter assays. A disruption of this pump (aha4-1) was identified as a T-DNA insertion in the middle of the gene (after VFP(574)). Truncated aha4-1 transcripts accumulate to approximately 50% of the level observed for AHA4 mRNA in wild-type plants. Plants homozygous for aha4-1 (-/-) show a subtle reduction in root and shoot growth compared with wild-type plants when grown under normal conditions. However, a mutant phenotype is very clear in plants grown under salt stress (e.g., 75 or 110 mM NaCl). In leaves of mutant plants subjected to Na stress, the ratio of Na to K increased 4-5-fold. Interestingly, the aha4-1 mutation appears to be semidominant and was only partially complemented by the introduction of additional wild-type copies of AHA4. These results are consistent with the hypothesis that aha4-1 may produce a dominant negative protein or RNA that partially disrupts the activity of other pumps or functions in the root endodermal tissue, thereby compromising the function of this cell layer in controlling ion homeostasis and nutrient transport.

Earth observations taken by the Expedition 14 crew

NASA Image and Video Library

2007-03-01

ISS014-E-15732 (1 March 2007) --- Salt ponds of Botswana are featured in this image photographed by an Expedition 14 crewmember on the International Space Station. This recent, detailed view shows the salt ponds of one of Africa's major producers of soda ash (sodium carbonate) and salt. Soda ash is used for glass making, in metallurgy, in the detergent industry, and in chemical manufacture. The image shows a small part of the great salt flats of central Botswana known as the Makgadikgadi Salt Pans. The soda ash and salt are both mainly exported (since 1989) to most countries in southern and central Africa. Brines from just beneath the pan floor are evaporated to produce the soda ash and salt -- a process for which the semiarid climate of Botswana is ideal. Red salt-loving algae in the ponds indicate that the salinity of the evaporating brines is medium to high. The salt pans of Botswana--a prominent visual photo target of interest for astronauts aboard the station--lie at the low point of a vast shallow continental basin. Rivers draining from as far away as central Angola - more than 1,000 kilometers away - supply water to the pans. According to scientists, during several wet climatic phases in the recent geological past the pans were permanently filled with water, for thousands of years, only to dry out when climates fluctuated to drier conditions. During dry phases water only reaches the pans underground. These are the brines that support the ash and salt industry. During wet phases when open water exists, beach ridges are constructed by wave action. One of these crosses the lower part of the view.

Electricity for groundwater use: constraints and opportunities for adaptive response to climate change

NASA Astrophysics Data System (ADS)

Scott, Christopher A.

2013-09-01

Globally, groundwater use is intensifying to meet demands for irrigation, urban supply, industrialization, and, in some instances, electrical power generation. In response to hydroclimatic variability, surface water is being substituted with groundwater, which must be viewed as a strategic resource for climate adaptation. In this sense, the supply of electricity for pumping is an adaptation policy tool. Additionally, planning for climate-change mitigation must consider CO2 emissions resulting from pumping. This paper examines the influence of electricity supply and pricing on groundwater irrigation and resulting emissions, with specific reference to Mexico—a climate-water-energy ‘perfect storm’. Night-time power supply at tariffs below the already-subsidized rates for agricultural groundwater use has caused Mexican farmers to increase pumping, reversing important water and electricity conservation gains achieved. Indiscriminate groundwater pumping, including for virtual water exports of agricultural produce, threatens the long-term sustainability of aquifers, non-agricultural water uses, and stream-aquifer interactions that sustain riparian ecosystems. Emissions resulting from agricultural groundwater pumping in Mexico are estimated to be 3.6% of total national emissions and are equivalent to emissions from transporting the same agricultural produce to market. The paper concludes with an assessment of energy, water, and climate trends coupled with policy futures to address these challenges.

Biological production in the Indian Ocean upwelling zones - Part 1: refined estimation via the use of a variable compensation depth in ocean carbon models

NASA Astrophysics Data System (ADS)

Geethalekshmi Sreeush, Mohanan; Valsala, Vinu; Pentakota, Sreenivas; Venkata Siva Rama Prasad, Koneru; Murtugudde, Raghu

2018-04-01

Biological modelling approach adopted by the Ocean Carbon-Cycle Model Intercomparison Project (OCMIP-II) provided amazingly simple but surprisingly accurate rendition of the annual mean carbon cycle for the global ocean. Nonetheless, OCMIP models are known to have seasonal biases which are typically attributed to their bulk parameterisation of compensation depth. Utilising the criteria of surface Chl a-based attenuation of solar radiation and the minimum solar radiation required for production, we have proposed a new parameterisation for a spatially and temporally varying compensation depth which captures the seasonality in the production zone reasonably well. This new parameterisation is shown to improve the seasonality of CO2 fluxes, surface ocean pCO2, biological export and new production in the major upwelling zones of the Indian Ocean. The seasonally varying compensation depth enriches the nutrient concentration in the upper ocean yielding more faithful biological exports which in turn leads to accurate seasonality in the carbon cycle. The export production strengthens by ˜ 70 % over the western Arabian Sea during the monsoon period and achieves a good balance between export and new production in the model. This underscores the importance of having a seasonal balance in the model export and new productions for a better representation of the seasonality of the carbon cycle over upwelling regions. The study also implies that both the biological and solubility pumps play an important role in the Indian Ocean upwelling zones.

Ion aggregation in high salt solutions. VII. The effect of cations on the structures of ion aggregates and water hydrogen-bonding network

NASA Astrophysics Data System (ADS)

Choi, Jun-Ho; Choi, Hyung Ran; Jeon, Jonggu; Cho, Minhaeng

2017-10-01

Ions in high salt solutions have a strong propensity to form polydisperse ion aggregates with broad size and shape distributions. In a series of previous comparative investigations using femtosecond IR pump-probe spectroscopy, molecular dynamics simulation, and graph theoretical analysis, we have shown that there exists a morphological difference in the structures of ion aggregates formed in various salt solutions. As salt concentration increases, the ions in high salt solutions form either cluster-like structures excluding water molecules or network-like structures entwined with water hydrogen-bonding networks. Interestingly, such morphological characteristics of the ion aggregates have been found to be in correlation with the solubility limits of salts. An important question that still remains unexplored is why certain salts with different cations have notably different solubility limits in water. Here, carrying out a series of molecular dynamics simulations of aqueous salt solutions and analyzing the distributions and connectivity patterns of ion aggregates with a spectral graph analysis method, we establish the relationship between the salt solubility and the ion aggregate morphology with a special emphasis on the cationic effects on water structures and ion aggregation. We anticipate that the understanding of large scale ion aggregate structures revealed in this study will be critical for elucidating the specific ion effects on the solubility and conformational stability of co-solute molecules such as proteins in water.

Salt controls feeding decisions in a blood-sucking insect.

PubMed

Pontes, Gina; Pereira, Marcos H; Barrozo, Romina B

2017-04-01

Salts are necessary for maintaining homeostatic conditions within the body of all living organisms. Like with all essential nutrients, deficient or excessive ingestion of salts can result in adverse health effects. The taste system is a primary sensory modality that helps animals to make adequate feeding decisions in terms of salt consumption. In this work we show that sodium and potassium chloride salts modulate the feeding behavior of Rhodnius prolixus in a concentration-dependent manner. Feeding is only triggered by an optimal concentration of any of these salts (0.1-0.15M) and in presence of the phagostimulant ATP. Conversely, feeding solutions that do not contain salts or have a high-salt concentration (>0.3M) are not ingested by insects. Notably, we show that feeding decisions of insects cannot be explained as an osmotic effect, because they still feed over hyperosmotic solutions bearing the optimal salt concentration. Insects perceive optimal-salt, no-salt and high-salt solutions as different gustatory information, as revealed the electromyogram recordings of the cibarial pump. Moreover, because insects do a continuous gustatory monitoring of the incoming food during feeding, sudden changes beyond the optimal sodium concentration decrease and even inhibit feeding. The administration of amiloride, a sodium channel blocker, noticeably reduces the ingestion of the optimal sodium solution but not of the optimal potassium solution. Salt detection seems to occur at least through two salt receptors, one amiloride-sensitive and another amiloride-insensitive. Our results confirm the importance of the gustatory system in R. prolixus, showing the relevant role that salts play on their feeding decisions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tdp studies and tests for C. A. Energia Electrica de Venezuela (enelven) at planta ramon laguna, units RL-17 and RL-10. Volume 3. Unit RL-10 turbine generator condition assessment report and units RL-10 and RL-11 boiler feed pump conditon assessment report. Export trade information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-03-28

The study, conducted by Babcock and Wilcox, was funded by the U.S. Trade and Development agency on behalf of Enelven. In order to maximize generated power output and minimize operating costs at Planta Ramon Laguna, tests were done to evaluate the condition of equipment at the plant. In order to identify any damage and determine the operating output of each unit, assessments were done of the furnaces, boilers, generators and boiler feed pumps being used in the plant. The report presents the results of these tests. This is the last of three volumes and it is divided into the followingmore » sections: (1) Condition Assessment of Unit RL-10 Turbine-Generator; (2) Condition Assessment of Unit RL-10 and RL-11 Boiler Feed Pumps.« less

Scanning electrochemical microscopy of menadione-glutathione conjugate export from yeast cells

PubMed Central

Mauzeroll, Janine; Bard, Allen J.

2004-01-01

The uptake of menadione (2-methyl-1,4-naphthoquinone), which is toxic to yeast cells, and its expulsion as a glutathione complex were studied by scanning electrochemical microscopy. The progression of the in vitro reaction between menadione and glutathione was monitored electrochemically by cyclic voltammetry and correlated with the spectroscopic (UV–visible) behavior. By observing the scanning electrochemical microscope tip current of yeast cells suspended in a menadione-containing solution, the export of the conjugate from the cells with time could be measured. Similar experiments were performed on immobilized yeast cell aggregates stressed by a menadione solution. From the export of the menadione-glutathione conjugate detected at a 1-μm-diameter electrode situated 10 μm from the cells, a flux of about 30,000 thiodione molecules per second per cell was extracted. Numerical simulations based on an explicit finite difference method further revealed that the observation of a constant efflux of thiodione from the cells suggested the rate was limited by the uptake of menadione and that the efflux through the glutathione-conjugate pump was at least an order of magnitude faster. PMID:15148374

Short communication: Massive erosion in monsoonal central India linked to late Holocene land cover degradation

NASA Astrophysics Data System (ADS)

Giosan, Liviu; Ponton, Camilo; Usman, Muhammed; Blusztajn, Jerzy; Fuller, Dorian Q.; Galy, Valier; Haghipour, Negar; Johnson, Joel E.; McIntyre, Cameron; Wacker, Lukas; Eglinton, Timothy I.

2017-12-01

Soil erosion plays a crucial role in transferring sediment and carbon from land to sea, yet little is known about the rhythm and rates of soil erosion prior to the most recent few centuries. Here we reconstruct a Holocene erosional history from central India, as integrated by the Godavari River in a sediment core from the Bay of Bengal. We quantify terrigenous fluxes, fingerprint sources for the lithogenic fraction and assess the age of the exported terrigenous carbon. Taken together, our data show that the monsoon decline in the late Holocene significantly increased soil erosion and the age of exported organic carbon. This acceleration of natural erosion was later exacerbated by the Neolithic adoption and Iron Age extensification of agriculture on the Deccan Plateau. Despite a constantly elevated sea level since the middle Holocene, this erosion acceleration led to a rapid growth of the continental margin. We conclude that in monsoon conditions aridity boosts rather than suppresses sediment and carbon export, acting as a monsoon erosional pump modulated by land cover conditions.

Method of preparing pure fluorine gas

DOEpatents

Asprey, Larned B.

1976-01-01

A simple, inexpensive system for purifying and storing pure fluorine is described. The method utilizes alkali metal-nickel fluorides to absorb tank fluorine by forming nickel complex salts and leaving the gaseous impurities which are pumped away. The complex nickel fluoride is then heated to evolve back pure gaseous fluorine.

The Response of Spartina Alterniflora to Multiple Stressors of Eutrophication, Precipitation Changes, and Sea Level Rise

EPA Science Inventory

A four month experiment using greenhouse mesocosms was conducted to analyze the effects of eutrophication, sea level rise, and precipitation changes on the salt marsh plant Spartina alterniflora. Pots containing plants were placed in six 600L tanks that received seawater pumped f...

Functional design criteria for interim stabilization safety class 1 trip circuit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larson, R.E., Westinghouse Hanford

1996-06-10

This Functional Design Criteria document outlines the basic requirements for the Safety Class 1 Trip Circuit. The objective of the Safety Class 1 Trip Circuit is to isolate the power circuitry to the Class 1 Division 2, Group B or lesser grade electrically fed loads located in the pump pit. The electrically fed load circuits need to have power isolated to them upon receipt of the following conditions, loss of flammable gases being released (above a predetermined threshold), and seismic(greater than 0.12g acceleration) activity. The two circuits requiring power isolation are the pump and heat trace power circuits. The Safetymore » Class 1 Trip Circuit will be used to support salt well pumping in SST`s containing potentially flammable gas-bearing / gas-producing radioactive waste.« less

Variable C : N : P stoichiometry of dissolved organic matter cycling in the Community Earth System Model

DOE PAGES

Letscher, R. T.; Moore, J. K.; Teng, Y. -C.; ...

2014-06-16

Dissolved organic matter (DOM) plays an important role in the ocean's biological carbon pump by providing an advective/mixing pathway for ~ 20% of export production. DOM is known to have a stoichiometry depleted in nitrogen (N) and phosphorus (P) compared to the particulate organic matter pool, a~fact that is often omitted from biogeochemical-ocean general circulation models. However the variable C : N : P stoichiometry of DOM becomes important when quantifying carbon export from the upper ocean and linking the nutrient cycles of N and P with that of carbon. Here we utilize recent advances in DOM observational data coveragemore » and offline tracer-modeling techniques to objectively constrain the variable production and remineralization rates of the DOM C / N / P pools in a simple biogeochemical-ocean model of DOM cycling. The optimized DOM cycling parameters are then incorporated within the Biogeochemical Elemental Cycling (BEC) component of the Community Earth System Model and validated against the compilation of marine DOM observations. The optimized BEC simulation including variable DOM C : N : P cycling was found to better reproduce the observed DOM spatial gradients than simulations that used the canonical Redfield ratio. Global annual average export of dissolved organic C, N, and P below 100 m was found to be 2.28 Pg C yr -1 (143 Tmol C yr -1), 16.4 Tmol N yr -1, and 1 Tmol P yr -1, respectively with an average export C : N : P stoichiometry of 225 : 19 : 1 for the semilabile (degradable) DOM pool. DOC export contributed ~ 25% of the combined organic C export to depths greater than 100 m.« less

Variable C : N : P stoichiometry of dissolved organic matter cycling in the Community Earth System Model

DOE PAGES

Letscher, R. T.; Moore, J. K.; Teng, Y. -C.; ...

2015-01-12

Dissolved organic matter (DOM) plays an important role in the ocean's biological carbon pump by providing an advective/mixing pathway for ~ 20% of export production. DOM is known to have a stoichiometry depleted in nitrogen (N) and phosphorus (P) compared to the particulate organic matter pool, a fact that is often omitted from biogeochemical ocean general circulation models. However the variable C : N : P stoichiometry of DOM becomes important when quantifying carbon export from the upper ocean and linking the nutrient cycles of N and P with that of carbon. Here we utilize recent advances in DOM observationalmore » data coverage and offline tracer-modeling techniques to objectively constrain the variable production and remineralization rates of the DOM C : N : P pools in a simple biogeochemical-ocean model of DOM cycling. The optimized DOM cycling parameters are then incorporated within the Biogeochemical Elemental Cycling (BEC) component of the Community Earth System Model (CESM) and validated against the compilation of marine DOM observations. The optimized BEC simulation including variable DOM C : N : P cycling was found to better reproduce the observed DOM spatial gradients than simulations that used the canonical Redfield ratio. Global annual average export of dissolved organic C, N, and P below 100 m was found to be 2.28 Pg C yr -1 (143 Tmol C yr -1, 16.4 Tmol N yr -1, and 1 Tmol P yr -1, respectively, with an average export C : N : P stoichiometry of 225 : 19 : 1 for the semilabile (degradable) DOM pool. Dissolved organic carbon (DOC) export contributed ~ 25% of the combined organic C export to depths greater than 100 m.« less

Infrared thermography of evaporative fluxes and dynamics of salt deposition on heterogeneous porous surfaces

NASA Astrophysics Data System (ADS)

Nachshon, Uri; Shahraeeni, Ebrahim; Or, Dani; Dragila, Maria; Weisbrod, Noam

2011-12-01

Evaporation of saline solutions from porous media, common in arid areas, involves complex interactions between mass transport, energy exchange and phase transitions. We quantified evaporation of saline solutions from heterogeneous sand columns under constant hydraulic boundary conditions to focus on effects of salt precipitation on evaporation dynamics. Mass loss measurements and infrared thermography were used to quantify evaporation rates. The latter method enables quantification of spatial and temporal variability of salt precipitation to identify its dynamic effects on evaporation. Evaporation from columns filled with texturally-contrasting sand using different salt solutions revealed preferential salt precipitation within the fine textured domains. Salt precipitation reduced evaporation rates from the fine textured regions by nearly an order of magnitude. In contrast, low evaporation rates from coarse-textured regions (due to low capillary drive) exhibited less salt precipitation and consequently less evaporation rate suppression. Experiments provided insights into two new phenomena: (1) a distinct increase in evaporation rate at the onset of evaporation; and (2) a vapor pumping mechanism related to the presence of a salt crust over semidry media. Both phenomena are related to local vapor pressure gradients established between pore water and the surface salt crust. Comparison of two salts: NaCl and NaI, which tend to precipitate above the matrix surface and within matrix pores, respectively, shows a much stronger influence of NaCl on evaporation rate suppression. This disparity reflects the limited effect of NaI precipitation on matrix resistivity for solution and vapor flows.

Salt stress-induced proline transporters and salt stress-repressed broad specificity amino acid permeases identified by suppression of a yeast amino acid permease-targeting mutant.

PubMed Central

Rentsch, D; Hirner, B; Schmelzer, E; Frommer, W B

1996-01-01

A yeast mutant lacking SHR3, a protein specifically required for correct targeting of plasma membrane amino acid permeases, was used to study the targeting of plant transporters and as a tool to isolate new SHR3-independent amino acid transporters. For this purpose, an shr3 mutant was transformed with an Arabidopsis cDNA library. Thirty-four clones were capable of growth under selective conditions, but none showed homology with SHR3. However, genes encoding eight different amino acid transporters belonging to three different transporter families were isolated. Five of these are members of the general amino acid permease (AAP) gene family, one is a member of the NTR family, encoding an oligopeptide transporter, and two belong to a new class of transporter genes. A functional analysis of the latter two genes revealed that they encode specific proline transporters (ProT) that are distantly related to the AAP gene family. ProT1 was found to be expressed in all organs, but highest levels were found in roots, stems, and flowers. Expression in flowers was highest in the floral stalk phloem that enters the carpels and was downregulated after fertilization, indicating a specific role in supplying the ovules with proline. ProT2 transcripts were found ubiquitously throughout the plant, but expression was strongly induced under water or salt stress, implying that ProT2 plays an important role in nitrogen distribution during water stress, unlike members of the AAP gene family whose expression was repressed under the same conditions. These results corroborate the general finding that under water stress, amino acid export is impaired whereas proline export is increased. PMID:8776904

Dubin-Johnson syndrome and intrahepatic cholestasis of pregnancy in a Sri Lankan family: a case report.

PubMed

Kularatnam, Grace Angeline Malarnangai; Warawitage, Dilanthi; Vidanapathirana, Dinesha Maduri; Jayasena, Subashini; Jasinge, Eresha; de Silva, Nalika; Liyanarachchi, Kirinda Liyana Arachchige Manoj Sanjeeva; Wickramasinghe, Pujitha; Devgun, Manjit Singh; Barbu, Veronique; Lascols, Olivier

2017-09-18

Dubin-Johnson syndrome and intrahepatic cholestasis of pregnancy are rare chronic liver disorders. Dubin-Johnson syndrome may manifest as conjugated hyperbilirubinemia, darkly pigmented liver, presence of abnormal pigment in the parenchyma of hepatocytes and abnormal distribution of the coproporphyrin isomers I and III in the urine. Intrahepatic cholestatic jaundice of pregnancy presents as pruritus, abnormal liver biochemistry and increased serum bile acids. A Sri Lankan girl presented with recurrent episodes of jaundice. She had conjugated hyperbilirubinaemia with diffuse, coarse brown pigments in the hepatocytes. Urine coproporphyrin examination suggested Dubin-Johnson syndrome. Genetic studies confirmed missense homozygous variant p.Trp709Arg in the ATP-binding cassette sub-family C member 2 gene ABCC2 that encodes the Multidrug resistance-associated protein 2 that causes Dubin-Johnson syndrome. The gene study of the mother revealed the same missense variant in ABCC2/MRP2 but with a heterozygous status, and in addition a homozygous missense variant p.Val444Ala in the ATP-binding cassette, sub-family B member 11 gene ABCB11 that encodes the bile salt export pump. Dubin-Johnson syndrome should be considered when the common causes for conjugated hyperbilirubinaemia have been excluded, and patient has an increased percentage of direct bilirubin relative to total bilirubin concentration. Its early diagnosis prevents repeated hospital admissions and investigations. Knowledge of a well known homozygous variant in ABCB11 gene could help in the management of pregnancy.

Analysis of Selected Functional Characteristics of Wetlands.

DTIC Science & Technology

1979-02-01

1978, Lead, Zinc, and Cadmium Budgets in Experimental- ly Enriched Salt Marsh Ecosystems, Eastern Coast, Mar. Sc.: Vol. 3, p. * 421-430. - -.q t...Sewage d and Retention of Lead, Zinc, and Cadmium by Marsh Sediments, Environ. Pollut., Vol. 7(Z), p. 149. Banus, M. D., et al., 1974, Export of Lead from...Hirshfield, H. 1., 1975, Cadmium in an Aquatic Ecosystem: Distribution and Effects, New York University, Medical Center, New York * Institute of Environmental

Integration of membrane distillation into traditional salt farming method: Process development and modelling

NASA Astrophysics Data System (ADS)

Hizam, S.; Bilad, M. R.; Putra, Z. A.

2017-10-01

Farmers still practice the traditional salt farming in many regions, particularly in Indonesia. This archaic method not only produces low yield and poor salt quality, it is also laborious. Furthermore, the farming locations typically have poor access to fresh water and are far away from electricity grid, which restrict upgrade to a more advanced technology for salt production. This paper proposes a new concept of salt harvesting method that improves the salt yield and at the same time facilitates recovery of fresh water from seawater. The new concept integrates solar powered membrane distillation (MD) and photovoltaic cells to drive the pumping. We performed basic solar still experiments to quantify the heat flux received by a pond. The data were used as insight for designing the proposed concept, particularly on operational strategy and the most effective way to integrate MD. After the conceptual design had been developed, we formulated mass and energy balance to estimate the performance of the proposed concept. Based on our data and design, it is expected that the system would improve the yield and quality of the salt production, maximizing fresh water harvesting, and eventually provides economical gain for salt farmers hence improving their quality of life. The key performance can only be measured via experiment using gain output ratio as performance indicator, which will be done in a future study.

Modification of ocean-estuary salt fluxes by density-driven advection of a headland eddy

NASA Astrophysics Data System (ADS)

Fram, J. P.; Stacey, M. T.

2005-05-01

Scalar exchange between San Francisco Bay and the coastal ocean is examined using shipboard observations made across the Golden Gate Channel. Ocean-estuary exchange is often described as a combination of two independent types of mechanisms: density-driven exchange such as gravitational circulation and tidal asymmetries such as tidal trapping. In this study we found that exchange is also governed by an interaction between these mechanisms. Tidally trapped eddies created in shallow shoals are mixed into the main channel earlier in the tidal cycle during the rainy season because the eddies are pushed seaward by gravitational circulation. This interaction increases the tidally averaged dispersive salt flux into the bay. The study consists of experiments during each of three 'seasons': winter/spring runoff (March 2002), summer upwelling (July 2003), and fall relaxation (October 2002). Within each experiment, transects across the channel were repeated approximately every 12 minutes for 25 hours during both spring tide and the following neap tide. Velocity was measured from a boat-mounted ADCP. Scalar concentrations were measured from a tow-yoed SeaSciences Acrobat. Salinity exchange over each spring-neap cycle is quantified with harmonic analysis. Harmonic results are decomposed into flux mechanisms using temporal and spatial correlations. The temporal correlation of cross-sectional averaged salinity and velocity (tidal pumping flux) is the largest part of the dispersive flux of salinity into the bay. From the tidal pumping portion of the dispersive flux, it is shown that there is less exchange than was found in earlier studies. Furthermore, tidal pumping flux scales strongly with flow due to density-driven movement of tidally trapped eddies and density-driven increases in ebb-flood frictional phasing. Complex bathymetry makes salinity exchange scale differently with flow than would be expected from simple tidal pumping and gravitational circulation models.

Simulated flow of groundwater and brine from a flooded salt mine in Livingston County, New York, and effects of remedial pumping on an overlying aquifer

USGS Publications Warehouse

Yager, Richard M.; Miller, Todd S.; Kappel, William M.; Misut, Paul E.; Langevin, Christian D.; Parkhurst, David L.; deVries, M. Peter

2012-01-01

Two ceiling collapses in the Retsof salt mine near Geneseo in upstate New York in spring 1994 resulted in the upward propagation of two columns of rubble through 600 feet of overlying shale and carbonate bedrock. This upward propagation formed a hydraulic connection between the lower confined aquifer (LCA) and the mine and allowed water from the aquifer and bedrock fracture zones that intersected the rubble columns to flow into the mine at a rate of 18,000 gallons per minute (gal/min) . All salt mining ceased in September 1995, and the mine was completely flooded by January 1996. The flow of water from the lower confined aquifer into the mine caused widespread drawdowns, and water levels in the aquifer declined by as much as 400 feet near the collapse area and by more than 50 feet at wells 7 miles to the north and south. Within 3 to 4 weeks of the collapses, water levels in about a dozen domestic and industrial wells had declined severely, and some wells went dry. Water levels in at least 58 wells in the lower and middle confined aquifers were affected by mine flooding. Groundwater in the upper unconfined aquifer and surface water in streams were unaffected by water-level drawdown, but channels of the Genesee River and Beards Creek were altered by land subsidence related to the mine collapse. Water levels recovered from 1996 through 2006, but the mine is now filled with about 15 billion gallons of saturated halite brine. The weight of the overlying rock and sediment is expected to cause the salt beds to deform and fill the mine cavity during the next several hundred years; this in turn could displace as much as 80 percent of the brine and cause it to move upward through the rubble chimneys, rendering the LCA unusable as a source of water supply. Saline water was detected in the LCA in 2002 but was found to be derived primarily from fractures in the limestone and shale units between the mine and the LCA, rather than from the mine. In September 2006, the mine company began a brine-mitigation project that entailed pumping five wells finished in limestone and shale units within the collapse areas to alter the flow gradient and thereby prevent further movement of brine and saline water into the LCA. The pumped brine was routed to an onsite desalination plant. At the same time, the U.S. Geological Survey (USGS) began a study in cooperation with the New York State Office of the Attorney General to construct numerical models to analyze the groundwater chemistry and delineate the directions of flow. Specific objectives of the study were to: * Assess the sources of salinity within the collapse area and identify the factors that control the movement and mixing of freshwater, saline waters from fracture zones, and brine; * Evaluate the likelihood that the pumping will induce anhydrite dissolution and lead to continued land subsidence; * Construct variable-density groundwater flow models to predict the effect of remedial pumping on salinity within the LCA; * Evaluate the effectiveness of remedial pumping in preventing the movement of saline water into the LCA; and * Predict the extent of brine migration 8 years after a hypothetical shutdown of all pumping in 2008. This report (1) summarizes the hydrogeologic setting and effects of mine flooding, (2) describes the geochemical and variable-density model simulations and their principal results, (3) discusses the implications of (a) continued pumping and desalination to protect the LCA and (b) a full shutdown of pumping after 2008, and (4) suggests further research that could lead to refinement of model predictions. Additional information may be found in Yager and others (2001 and 2009). These reports can be accessed at http://pubs.usgs.gov/pp/pp1611/ and http://pubs.usgs.gov/pp/pp1767/, respectively. A summary of simulation results can be accessed at http://ny.water.usgs.gov/projects/Coram/seawat/seawat.html.

Major Texas floods of 1935

USGS Publications Warehouse

Dalrymple, Tate

1939-01-01

In localities where highly mineralized water is present in beds above and below the beds that yield the supplies of fresh water it is necessary to be able to locate leaks in wells in order to know whether the wells are being contaminated through holes in the casings or whether the fresh water supply is failing. Four general methods of detecting salt-water leaks have been used. In the pumping method, samples taken at measured time intervals while the well is being pumped show by their progressive change in salinity if salt water is being drawn in. In the velocity method, which is suitable for use only in artesian wells, a current meter lowered into the well indicates the location of possible salt water leaks by determining the levels at which there are changes in the rate of upward movement of the water. In the sampler method a container lowered into the well brings up a sample from any depth desired for analysis of its chloride content. The electric conductivity method, for which special apparatus was designed, has been used successfully in the Winter Garden area and Kleberg County, Tex., and in Sarasota County, Fla. The procedure in this method was to lower a pair of insulated electrodes into the well and measure the resistance of the water between them with the Wheatstone bridge or, in waters low in chloride, to apply a direct current of low voltage and measure the current flowing between .the electrodes by means of a milliammeter. The installments showed a marked increase in the conductivity of the water as the electrodes passed from fresh to salt water in the well, leaving no doubt as to the location of the leaks.

Ultrafast gigantic photo-response in (EDO-TTF)2PF6 initiated by 10-fs laser pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoenlein, Robert William; Itatani, Jiro; Rini, Matteo

2006-08-07

We photo-exited a charge-ordered organic salt (EDO-TTF)2PF6 with sub-10-fs optical pulses. The photo-induced metallic phase appeared within 80-fs after pumping, characterized by large changes in reflectivity (DELTA R/R~0.8) followed by strong coherent phonon modulation

Hydrologic data, 1974-77, Stovepipe Wells Hotel area, Death Valley National Monument, Inyo County, California

USGS Publications Warehouse

Lamb, Charles Edwin; Downing, D.J.

1979-01-01

Ground-water levels in most wells did not change significantly from 1974 to 1977 in the Stovepipe Wells Hotel area, California. The average water-level decline was less than 0.10 foot between August 1974 and August 1977 in 10 observation wells. Water-level contours show a depression centered on the two pumping wells, but this depression existed before the National Park Service started pumping its well. The chemical quality of the ground water is poor. Dissolved-solids concentrations in water samples ranged from 2,730 to 6,490 milligrams per liter. Analyses of water samples from two wells showed large changes in some constituents from 1976 to 1977. Streamflow in Salt Creek has been monitored since February 1974. Base flow is seasonal, being 0.10 to 0.20 cubic foot per second during the summer and as much as three times that amount during the winter. Two chemical analyses of water from Salt Creek, representing summer and winter flow conditions, show large differences for many constituents. (Woodard-USGS)

Bench Scale Saltcake Dissolution Test Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

BECHTOLD, D.B.; PACQUET, E.A.

A potential scenario for retrieving saltcake from single shell tanks is the ''Rainbird{reg_sign} sprinkler'' method. Water is distributed evenly across the surface of the saltcake and allowed to percolate by gravity through the waste. The salt dissolves in the water, forming a saturated solution. The saturated liquid is removed by a saltwell pump situated near the bottom of the tank. By this method, there is never a large inventory of liquid in the tank that could pose a threat of leakage. There are many variables or factors that can influence the hydrodynamics of this retrieval process. They include saltcake porosity;more » saltwell pumping rate; salt dissolution chemistry; factors that could promote flow channeling (e.g. tank walls, dry wells, inclusions or discontinuities in the saltcake); method of water distribution; plug formation due to crystal formations or accumulation of insoluble solids. A brief literature search indicates that very little experimental data exist on these aspects of saltcake dissolution (Wiersma 1996, 1997). The tests reported here were planned (Herting, 2000) to provide preliminary data and information for planning future, scaled-up tests of the sprinkler method.« less

Xenobiotic, Bile Acid, and Cholesterol Transporters: Function and Regulation

PubMed Central

Aleksunes, Lauren M.

2010-01-01

Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting β polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) α and β] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory factors that influence transporter expression and function, including transcriptional activation and post-translational modifications as well as subcellular trafficking. Sex differences, ontogeny, and pharmacological and toxicological regulation of transporters are also addressed. Transporters are important transmembrane proteins that mediate the cellular entry and exit of a wide range of substrates throughout the body and thereby play important roles in human physiology, pharmacology, pathology, and toxicology. PMID:20103563

Schedules of Controlled Substances: Placement of Three Synthetic Phenethylamines Into Schedule I. Final rule.

PubMed

2016-09-27

With the issuance of this final rule, the Administrator of the Drug Enforcement Administration places three synthetic phenethylamines: 2-(4-iodo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25I-NBOMe; 2C-I-NBOMe; 25I; Cimbi-5), 2-(4-chloro-2,5-dimethoxyphenyl)-N- (2-methoxybenzyl)ethanamine (25C-NBOMe; 2C-C-NBOMe; 25C; Cimbi-82), and 2-(4-bromo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25B- NBOMe; 2C-B-NBOMe; 25B; Cimbi-36), including their optical, positional, and geometric isomers, salts and salts of isomers, whenever the existence of such salts, isomers, and salts of isomers is possible, into schedule I of the Controlled Substances Act. This scheduling action is pursuant to the Controlled Substances Act which requires that such actions be made on the record after opportunity for a hearing through formal rulemaking. This action continues the application of the regulatory controls and administrative, civil, and criminal sanctions applicable to schedule I controlled substances on persons who handle (manufacture, distribute, reverse distribute, import, export, engage in research, conduct instructional activities or chemical analysis, or possess), or propose to handle 25I-NBOMe, 25C-NBOMe, or 25B-NBOMe.

Simulated ground-water flow for a pond-dominated aquifer system near Great Sandy Bottom Pond, Pembroke, Massachusetts

USGS Publications Warehouse

Carlson, Carl S.; Lyford, Forest P.

2005-01-01

A ground-water flow simulation for a 66.4-square-mile area around Great Sandy Bottom (GSB) Pond (105 acres) near Pembroke, Massachusetts, was developed for use by local and State water managers to assess the yields for public water supply of local ponds and wells for average climatic and drought conditions and the effects of water withdrawals on nearby water levels and streamflows. Wetlands and ponds cover about 30 percent of the study area and the aquifer system is dominated by interactions between ground water and the ponds. The three largest surface-water bodies in the study area are Silver Lake (640 acres), Monponsett Pond (590 acres), and Oldham Pond (236 acres). The study area is drained by tributaries of the Taunton River to the southwest, the South and North Rivers to the northeast, and the Jones River to the southeast. In 2002, 10.8 million gallons per day of water was exported from ponds and 3.5 million gallons per day from wells was used locally for public supply. A transient ground-water-flow model with 69 monthly stress periods spanning the period from January 1998 through September 2003 was calibrated to stage at GSB Pond and nearby Silver Lake and streamflow and water levels collected from September 2002 through September 2003. The calibrated model was used to assess hydrologic responses to a variety of water-use and climatic conditions. Simulation of predevelopment (no pumping or export) average monthly (1949-2002) water-level conditions caused the GSB Pond level to increase by 6.3 feet from the results of a simulation using average 2002 pumping for all wells, withdrawals, and exports. Most of this decline can be attributed to pumping, withdrawals, and exports of water from sites away from GSB Pond. The effects of increasing the export rate from GSB Pond by 1.25 and 1.5 times the 2002 rate were a lowering of pond levels by a maximum of 1.6 and 2.8 feet, respectively. Simulated results for two different drought conditions, one mild drought similar to that of 1979-82 and a more severe drought similar to that of 1963-66, but with current (2002) pumping, were compared to results for average monthly recharge conditions (1949-2002). Simulated mild drought conditions showed a reduction of GSB Pond level of about 1.3 feet and a lower streamflow of about 1.7 percent in the nearby stream. Simulated severe drought conditions reduced the pond level at GSB Pond by almost 7 feet and lowered streamflow by about 37 percent. Varying cranberry-irrigation practices had little effect on simulated GSB Pond water levels, but may be important in other ponds. The model was most sensitive to changes in areal recharge. An increase and decrease of 22 percent in recharge produced changes in the GSB Pond water level of +1.4 feet and -2.4 feet, respectively. The accuracy of simulation results was best in the central portion of the study area in the immediate location of GSB Pond. The model was developed with the study-area boundary far enough away from the GSB Pond area that the boundary would have minimal effect on the water levels in GSB Pond, nearby ponds, and the underlying aquifer system. The model is best suited for use by local and State water managers to assess the effects of different withdrawal scenarios for wells and ponds near GSB Pond and for general delineation of areas contributing recharge to wells and ponds in the vicinity of GSB Pond. The model in its current form may not be well suited to detailed analyses of water budgets and flow patterns for parts of the study area farther from GSB Pond without further investigation, calibration, and data collection.

STS-48 ESC Earth observation of southwestern corner of the Great Salt Lake

NASA Technical Reports Server (NTRS)

1991-01-01

STS-48 Earth observation of the southwestern corner of the Great Salt Lake, 308 nautical miles below Discovery, Orbiter Vehicle (OV) 103, was provided by the electronic still camera (ESC). While the image is mostly covered with a thin veil of cirrus clouds, many of the surface features can be recognized. The causeway linking the northern tip of the peninsula to the southwest shore of the lake is clearly visible as is the interstate highway. Considerable topographic detail is visible in the snow covered peaks to the south of the lake. The commercial salt pans between the peninsula and the interstate show high contrast with the brightness dependent on the concentration of the brackish water in the pan. Recent heavy rainfall has caused considerable runoff into the lake but the flooding hazard of a few years past no longer exists due to a pumping system that now transfers excess water to the Bonneville Salt Flats. The ESC image was stored on a removable hard disk or small optical disk and

Sustaining nutrient supply and carbon export in a seasonally-stratifying shelf sea through inconsistent production and remineralisation stoichiometry

NASA Astrophysics Data System (ADS)

Humphreys, Matthew; Moore, Mark; Achterberg, Eric; Chowdhury, Mohammed; Griffiths, Alex; Hartman, Susan; Hopkins, Joanne; Hull, Tom; Kivimäe, Caroline; Sivyer, Dave; Smilenova, Angelina; Wihsgott, Juliane; Woodward, Malcolm

2017-04-01

Continental shelf seas support 15-20% of global primary productivity despite covering only about 5% of the Earth's ocean surface area. As a result, they may have a significant role in oceanic uptake and storage of carbon dioxide (CO2) from the atmosphere, through the 'continental shelf pump' mechanism. The northwest European continental shelf, in particular the Celtic Sea (50°N 8°W), was the target of extensive biogeochemical sampling from March 2014 to September 2015, as part of the UK Shelf Sea Biogeochemistry research programme (UK-SSB). Here, we use the UK-SSB carbonate chemistry and macronutrient measurements to investigate the biogeochemical seasonality in the temperate, seasonally-stratifying Celtic Sea. During the spring-summer, near-surface biological activity removed dissolved inorganic carbon and nutrients, some of which were then exported into the deeper layer. We calculated vertical inventories of these variables throughout 1.5 seasonal cycles and attempted to correct these for air-sea CO2 exchange, advection and denitrification, thus isolating the combined effect of net community production and remineralisation on the inorganic macronutrient inventories, and revealing fluctuating deviations from Redfield stoichiometry. Here, we discuss the capacity of these stoichiometric inconsistencies to sustain the Celtic Sea nutrient supply, and thus examine whether an effective continental shelf pump for CO2 could operate in this region.

Substantial energy input to the mesopelagic ecosystem from the seasonal mixed-layer pump

PubMed Central

Dall’Olmo, Giorgio; Dingle, James; Polimene, Luca; Brewin, Robert J.W.; Claustre, Hervé

2016-01-01

The “mesopelagic” is the region of the ocean between about 100 and 1000 m that harbours one of the largest ecosystems and fish stocks on the planet1,2. This vastly unexplored ecosystem is believed to be mostly sustained by chemical energy, in the form of fast-sinking particulate organic carbon, supplied by the biological carbon pump3. Yet, this supply appears insufficient to match mesopelagic metabolic demands4–6. The mixed-layer pump is a physically-driven biogeochemical process7–11 that could further contribute to meet these energetic requirements. However, little is known about the magnitude and spatial distribution of this process at the global scale. Here we show that the mixed-layer pump supplies an important seasonal flux of organic carbon to the mesopelagic. By combining mixed-layer depths from Argo floats with satellite retrievals of particulate organic carbon, we estimate that this pump exports a global flux of about 0.3 Pg C yr−1 (range 0.1 – 0.5 Pg C yr−1). In high-latitude regions where mixed-layers are deep, this flux is on average 23%, but can be greater than 100% of the carbon supplied by fast sinking particles. Our results imply that a relatively large flux of organic carbon is missing from current energy budgets of the mesopelagic. PMID:27857779

High particulate organic carbon export during the decline of a vast diatom bloom in the Atlantic sector of the Southern Ocean

NASA Astrophysics Data System (ADS)

Roca-Martí, Montserrat; Puigcorbé, Viena; Iversen, Morten H.; van der Loeff, Michiel Rutgers; Klaas, Christine; Cheah, Wee; Bracher, Astrid; Masqué, Pere

2017-04-01

Carbon fixation by phytoplankton plays a key role in the uptake of atmospheric CO2 in the Southern Ocean. Yet, it still remains unclear how efficiently the particulate organic carbon (POC) is exported and transferred from ocean surface waters to depth during phytoplankton blooms. In addition, little is known about the processes that control the flux attenuation within the upper twilight zone. Here, we present results of downward POC and particulate organic nitrogen fluxes during the decline of a vast diatom bloom in the Atlantic sector of the Southern Ocean in summer 2012. We used thorium-234 (234Th) as a particle tracer in combination with drifting sediment traps (ST). Their simultaneous use evidenced a sustained high export rate of 234Th at 100 m depth in the weeks prior to and during the sampling period. The entire study area, of approximately 8000 km2, showed similar vertical export fluxes in spite of the heterogeneity in phytoplankton standing stocks and productivity, indicating a decoupling between production and export. The POC fluxes at 100 m were high, averaging 26±15 mmol C m-2 d-1, although the strength of the biological pump was generally low. Only <20% of the daily primary production reached 100 m, presumably due to an active recycling of carbon and nutrients. Pigment analyses indicated that direct sinking of diatoms likely caused the high POC transfer efficiencies ( 60%) observed between 100 and 300 m, although faecal pellets and transport of POC linked to zooplankton vertical migration might have also contributed to downward fluxes.

Do Continental Shelves Act as an Atmospheric CO2 Sink?

NASA Astrophysics Data System (ADS)

Cai, W.

2003-12-01

Recent air-to-sea CO2 flux measurements at several major continental shelves (European Atlantic Shelves, East China Sea and U.S. Middle Atlantic Bight) suggest that shelves may act as a one-way pump and absorb atmospheric CO2 into the ocean. These observations also favor the argument that continental shelves are autotrophic (i.e., net production of organic carbon, OC). The U.S. South Atlantic Bight (SAB) contrasts these findings in that it acts as a strong source of CO2 to the atmosphere while simultaneously exporting dissolved inorganic carbon (DIC) to the open ocean. We report pCO2, DIC, and alkalinity data from the SAB collected in 8 cruises along a transect from the shore to the shelf break in the central SAB. The shelf-wide net heterotrophy and carbon exports in the SAB are subsidized by the export of OC from the abundant intertidal marshes, which are a sink for atmospheric CO2. It is proposed here that the SAB represents a marsh-dominated heterotrophic ocean margin as opposed to river-dominated autotrophic margins. To further investigate why margins may behave differently in term of CO2 sink/source, the physical and biological conditions of several western boundary current margins are compared. Based on this and other studies, DIC export flux from margins to the open ocean must be significant in the overall global ocean carbon budget.

Iron defecation by sperm whales stimulates carbon export in the Southern Ocean

PubMed Central

Lavery, Trish J.; Roudnew, Ben; Gill, Peter; Seymour, Justin; Seuront, Laurent; Johnson, Genevieve; Mitchell, James G.; Smetacek, Victor

2010-01-01

The iron-limited Southern Ocean plays an important role in regulating atmospheric CO2 levels. Marine mammal respiration has been proposed to decrease the efficiency of the Southern Ocean biological pump by returning photosynthetically fixed carbon to the atmosphere. Here, we show that by consuming prey at depth and defecating iron-rich liquid faeces into the photic zone, sperm whales (Physeter macrocephalus) instead stimulate new primary production and carbon export to the deep ocean. We estimate that Southern Ocean sperm whales defecate 50 tonnes of iron into the photic zone each year. Molar ratios of Cexport ∶Feadded determined during natural ocean fertilization events are used to estimate the amount of carbon exported to the deep ocean in response to the iron defecated by sperm whales. We find that Southern Ocean sperm whales stimulate the export of 4 × 105 tonnes of carbon per year to the deep ocean and respire only 2 × 105 tonnes of carbon per year. By enhancing new primary production, the populations of 12 000 sperm whales in the Southern Ocean act as a carbon sink, removing 2 × 105 tonnes more carbon from the atmosphere than they add during respiration. The ability of the Southern Ocean to act as a carbon sink may have been diminished by large-scale removal of sperm whales during industrial whaling. PMID:20554546

Fusible pellet transport and storage of heat

NASA Technical Reports Server (NTRS)

Bahrami, P. A.

1982-01-01

A new concept for both transport and storage of heat at high temperatures and heat fluxes is introduced and the first steps in analysis of its feasibility is taken. The concept utilizes the high energy storage capability of materials undergoing change of phase. The phase change material, for example a salt, is encapsulated in corrosion resistant sealed pellets and transported in a carrier fluid to heat source and storage. Calculations for heat transport from a typical solar collector indicate that the pellet mass flow rates are relatively small and that the required pumping power is only a small fraction of the energy transport capability of the system. Salts and eutectic salt mixtures as candidate phase change materials are examined and discussed. Finally, the time periods for melting or solidification of sodium chloride pellets is investigated and reported.

Fusible pellet transport and storage of heat

NASA Astrophysics Data System (ADS)

Bahrami, P. A.

1982-06-01

A new concept for both transport and storage of heat at high temperatures and heat fluxes is introduced and the first steps in analysis of its feasibility is taken. The concept utilizes the high energy storage capability of materials undergoing change of phase. The phase change material, for example a salt, is encapsulated in corrosion resistant sealed pellets and transported in a carrier fluid to heat source and storage. Calculations for heat transport from a typical solar collector indicate that the pellet mass flow rates are relatively small and that the required pumping power is only a small fraction of the energy transport capability of the system. Salts and eutectic salt mixtures as candidate phase change materials are examined and discussed. Finally, the time periods for melting or solidification of sodium chloride pellets is investigated and reported.

Analysis of Shigella flexneri Resistance, Biofilm Formation, and Transcriptional Profile in Response to Bile Salts

PubMed Central

Nickerson, Kourtney P.; Chanin, Rachael B.; Sistrunk, Jeticia R.; Fink, Peter J.; Barry, Eileen M.; Nataro, James P.

2017-01-01

ABSTRACT The Shigella species cause millions of cases of watery or bloody diarrhea each year, mostly in children in developing countries. While many aspects of Shigella colonic cell invasion are known, crucial gaps in knowledge regarding how the bacteria survive, transit, and regulate gene expression prior to infection remain. In this study, we define mechanisms of resistance to bile salts and build on previous research highlighting induced virulence in Shigella flexneri strain 2457T following exposure to bile salts. Typical growth patterns were observed within the physiological range of bile salts; however, growth was inhibited at higher concentrations. Interestingly, extended periods of exposure to bile salts led to biofilm formation, a conserved phenotype that we observed among members of the Enterobacteriaceae. Characterization of S. flexneri 2457T biofilms determined that both bile salts and glucose were required for formation, dispersion was dependent upon bile salts depletion, and recovered bacteria displayed induced adherence to HT-29 cells. RNA-sequencing analysis verified an important bile salt transcriptional profile in S. flexneri 2457T, including induced drug resistance and virulence gene expression. Finally, functional mutagenesis identified the importance of the AcrAB efflux pump and lipopolysaccharide O-antigen synthesis for bile salt resistance. Our data demonstrate that S. flexneri 2457T employs multiple mechanisms to survive exposure to bile salts, which may have important implications for multidrug resistance. Furthermore, our work confirms that bile salts are important physiological signals to activate S. flexneri 2457T virulence. This work provides insights into how exposure to bile likely regulates Shigella survival and virulence during host transit and subsequent colonic infection. PMID:28348056

Simulating water-quality trends in public-supply wells in transient flow systems

USGS Publications Warehouse

Starn, J. Jeffrey; Green, Christopher T.; Hinkle, Stephen R.; Bagtzoglou, Amvrossios C.; Stolp, Bernard J.

2014-01-01

Models need not be complex to be useful. An existing groundwater-flow model of Salt Lake Valley, Utah, was adapted for use with convolution-based advective particle tracking to explain broad spatial trends in dissolved solids. This model supports the hypothesis that water produced from wells is increasingly younger with higher proportions of surface sources as pumping changes in the basin over time. At individual wells, however, predicting specific water-quality changes remains challenging. The influence of pumping-induced transient groundwater flow on changes in mean age and source areas is significant. Mean age and source areas were mapped across the model domain to extend the results from observation wells to the entire aquifer to see where changes in concentrations of dissolved solids are expected to occur. The timing of these changes depends on accurate estimates of groundwater velocity. Calibration to tritium concentrations was used to estimate effective porosity and improve correlation between source area changes, age changes, and measured dissolved solids trends. Uncertainty in the model is due in part to spatial and temporal variations in tracer inputs, estimated tracer transport parameters, and in pumping stresses at sampling points. For tracers such as tritium, the presence of two-limbed input curves can be problematic because a single concentration can be associated with multiple disparate travel times. These shortcomings can be ameliorated by adding hydrologic and geologic detail to the model and by adding additional calibration data. However, the Salt Lake Valley model is useful even without such small-scale detail.

PILOT-SCALE REMOVAL OF FLUORIDE FROM LEGACY PLUTONIUM MATERIALS USING VACUUM SALT DISTILLATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R. A.; Pak, D. J.

2012-09-11

Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and HB-Line designed, developed, tested, and successfully deployed a system for the distillation of chloride salts. In 2011, SRNL adapted the technology for the removal of fluoride from fluoride-bearing salts. The method involved an in situ reaction between potassium hydroxide (KOH) and the fluoride salt to yield potassium fluoride (KF) and the corresponding oxide. The KF and excess KOH can be distilled below 1000{deg}C using vacuum salt distillation (VSD). The apparatus for vacuum distillation contains a zone heated by a furnace and a zone actively cooled using eithermore » recirculated water or compressed air. During a vacuum distillation operation, a sample boat containing the feed material is placed into the apparatus while it is cool, and the system is sealed. The system is evacuated using a vacuum pump. Once a sufficient vacuum is attaned, heating begins. Volatile salts distill from the heated zone to the cooled zone where they condense, leaving behind the non-volatile material in the feed boat. Studies discussed in this report were performed involving the use of non-radioactive simulants in small-scale and pilot-scale systems as well as radioactive testing of a small-scale system with plutonium-bearing materials. Aspects of interest include removable liner design considerations, boat materials, in-line moisture absorption, and salt deposition.« less

Quantitative Proteomics of the Tonoplast Reveals a Role for Glycolytic Enzymes in Salt Tolerance[C][W

PubMed Central

Barkla, Bronwyn J.; Vera-Estrella, Rosario; Hernández-Coronado, Marcela; Pantoja, Omar

2009-01-01

To examine the role of the tonoplast in plant salt tolerance and identify proteins involved in the regulation of transporters for vacuolar Na+ sequestration, we exploited a targeted quantitative proteomics approach. Two-dimensional differential in-gel electrophoresis analysis of free flow zonal electrophoresis separated tonoplast fractions from control, and salt-treated Mesembryanthemum crystallinum plants revealed the membrane association of glycolytic enzymes aldolase and enolase, along with subunits of the vacuolar H+-ATPase V-ATPase. Protein blot analysis confirmed coordinated salt regulation of these proteins, and chaotrope treatment indicated a strong tonoplast association. Reciprocal coimmunoprecipitation studies revealed that the glycolytic enzymes interacted with the V-ATPase subunit B VHA-B, and aldolase was shown to stimulate V-ATPase activity in vitro by increasing the affinity for ATP. To investigate a physiological role for this association, the Arabidopsis thaliana cytoplasmic enolase mutant, los2, was characterized. These plants were salt sensitive, and there was a specific reduction in enolase abundance in the tonoplast from salt-treated plants. Moreover, tonoplast isolated from mutant plants showed an impaired ability for aldolase stimulation of V-ATPase hydrolytic activity. The association of glycolytic proteins with the tonoplast may not only channel ATP to the V-ATPase, but also directly upregulate H+-pump activity. PMID:20028841

Quantitative proteomics of the tonoplast reveals a role for glycolytic enzymes in salt tolerance.

PubMed

Barkla, Bronwyn J; Vera-Estrella, Rosario; Hernández-Coronado, Marcela; Pantoja, Omar

2009-12-01

To examine the role of the tonoplast in plant salt tolerance and identify proteins involved in the regulation of transporters for vacuolar Na(+) sequestration, we exploited a targeted quantitative proteomics approach. Two-dimensional differential in-gel electrophoresis analysis of free flow zonal electrophoresis separated tonoplast fractions from control, and salt-treated Mesembryanthemum crystallinum plants revealed the membrane association of glycolytic enzymes aldolase and enolase, along with subunits of the vacuolar H(+)-ATPase V-ATPase. Protein blot analysis confirmed coordinated salt regulation of these proteins, and chaotrope treatment indicated a strong tonoplast association. Reciprocal coimmunoprecipitation studies revealed that the glycolytic enzymes interacted with the V-ATPase subunit B VHA-B, and aldolase was shown to stimulate V-ATPase activity in vitro by increasing the affinity for ATP. To investigate a physiological role for this association, the Arabidopsis thaliana cytoplasmic enolase mutant, los2, was characterized. These plants were salt sensitive, and there was a specific reduction in enolase abundance in the tonoplast from salt-treated plants. Moreover, tonoplast isolated from mutant plants showed an impaired ability for aldolase stimulation of V-ATPase hydrolytic activity. The association of glycolytic proteins with the tonoplast may not only channel ATP to the V-ATPase, but also directly upregulate H(+)-pump activity.

On the applicability of a hybrid bioreactor operated with polymeric tubing for the biological treatment of saline wastewater.

PubMed

Tomei, M Concetta; Mosca Angelucci, Domenica; Stazi, Valentina; Daugulis, Andrew J

2017-12-01

Effective biological treatment of high salt content wastewater requires consideration of both salt and organic toxicity. This study treated a synthetic saline wastewater containing NaCl (100gL -1 ) and 2,4-dimethylphenol (1.2gL -1 ) with a hybrid system consisting of a biological reactor containing spiral-coiled polymeric tubing through which the mixed feed was pumped. The tubing wall was permeable to the organic contaminant, but not to the salt, which allowed transfer of the organic into the cell-containing bioreactor contents for degradation, while not exposing the cells to high salt concentrations. Different grades of DuPont Hytrel polymer were examined on the basis of organic affinity predictions and experimental partition and mass transfer tests. Hytrel G3548 tubing showed the highest permeability for 2,4-dimethylphenol while exerting an effective salt barrier, and was used to verify the feasibility of the proposed system. Very high organic removal (99% after just 5h of treatment) and effective biodegradation of the organic fraction of the wastewater (>90% at the end of the test) were observed. Complete salt separation from the microbial culture was also achieved. Copyright © 2017 Elsevier B.V. All rights reserved.

40 CFR Appendix to Subpart Cc of... - Tables

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Tables Appendix to Subpart CC of Part... to Subpart CC of Part 63—Tables Table 1—Hazardous Air Pollutants Chemical name CAS No.a Benzene 71432... salts, esters, or derivatives. Table 2—Leak Definitions for Pumps and Valves Standard a Phase Leak...

40 CFR Appendix to Subpart Cc of... - Tables

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Tables Appendix to Subpart CC of Part... to Subpart CC of Part 63—Tables Table 1—Hazardous Air Pollutants Chemical name CAS No.a Benzene 71432... salts, esters, or derivatives. Table 2—Leak Definitions for Pumps and Valves Standard a Phase Leak...

40 CFR Appendix to Subpart Cc of... - Tables

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Tables Appendix to Subpart CC of Part... to Subpart CC of Part 63—Tables Table 1—Hazardous Air Pollutants Chemical name CAS No.a Benzene 71432... salts, esters, or derivatives. Table 2—Leak Definitions for Pumps and Valves Standard a Phase Leak...

10. Photocopy of photograph (original in SRP Archives) Probably photographed ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Photocopy of photograph (original in SRP Archives) Probably photographed by SRP, March 15, 1941 INDIAN BEND WELL STRUCTURE FOR SUPPLYING WATER TO CROSSCUT DIESEL PLANT, NEAR PROPOSED LOCATION OF (INDIAN BEND) SETTLING POND. - Crosscut Steam Plant, Indian Bend Pond & Pump Ditch, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

Utah geothermal commercialization planning. Semi-annual progress report, January 1, 1979--June 30, 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, S.; Wagstaff, L.W.

1979-06-01

The effects of the Utah geothermal planning project were concentrated on the Utah geothermal legislation, the Roosevelt Hot Springs time phased project plan and the Salt Lake County area development plan. Preliminary findings indicate a potential for heat pump utilization, based on market interest and the existence of suitable groundwater conditions. (MHR)

Feasibility study for the construction of a new LNG receiving terminal, turkey. Volume 2. Appendix. Export trade information. [LNG (liquified natural gas)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-06-01

The report was prepared by The M. W. Kellogg Co. for BOTAS Petroleum Pipeline Corporation of Ankara, Turkey. The study was undertaken to evaluate the cost and economics of constructing a second liquified natural gas (LNG) terminal in Turkey to meet future requirements for natural gas. Volume 2 contains the following appendices: LNG Storage Tanks; Vaporizers; Compressors; Pumps; Loading Arms; Marine Installations; Shipping; and Seismic Study.

Longtime variation of phytoplankton in the South China Sea from the perspective of carbon fixation

NASA Astrophysics Data System (ADS)

Li, Teng; Bai, Yan; Chen, Xiaoyan; Zhu, Qiankun; Gong, Fang; Wang, Difeng

2017-10-01

The ocean is a huge carbon pool in the earth, and about half of the anthropogenic emissions of carbon dioxide are absorbed by the ocean each year. By converting inorganic carbon into organic carbon, the photosynthesis process of phytoplankton affords an important way for carbon sequestration in the ocean. According to previous researches, primary production (NPP) and the structure of phytoplankton community are important in regulate the efficiency of biological carbon pump. This study examined the spatiotemporal variability of satellite remote sensing derived chlorophyll a concentration (Chla), phytoplankton carbon biomass (Carbon), composition ratio of micro-, nano- and pico- phytoplankton, NPP and integrated particulate organic carbon (IPOC) during 1998-2007 in the South China Sea (SCS). Micro-, nano-phytoplankton and NPP showed similar seasonal variation with highest values in winter (January) (especially in the western ocean of Luzon Strait) and lowest values in summer (July) in SCS. Chla, phytoplankton carbon biomass, and IPOC showed different seasonal trends with one peak values occurred in winter and lowest in spring. Two sampling areas (A, N:17-21°, E:117.5-120° and B, N:12.5-15°, E:112-119°) in SCS were selected based on spatial distribution of the standard deviation of research parameters mentioned above. Compared to Chla, phytoplankton carbon biomass, NPP and IPOC, the interannual changes of phytoplankton community structure were remarkable in the two areas. The fraction of micro- and nano- phytoplankton in SCS tend to rise when La Nina events occur. Our results contribute to an understanding of the response of phytoplankton to climate change in the marginal sea. To quantify the efficiency of biological carbon pump in this area, more attention should be paid to the development of remote sensing algorithms of export NPP (or POC export flux) as well as the regulate mechanism of export NPP.

Zooplankton diel vertical migration and contribution to deep active carbon flux in the NW Mediterranean

NASA Astrophysics Data System (ADS)

Isla, Alejandro; Scharek, Renate; Latasa, Mikel

2015-03-01

The diel vertical migration (DVM) of zooplankton contributes to the biological pump transporting material from surface to deep waters. We examined the DVM of the zooplankton community in different size fractions (53-200 μm, 200-500 μm, 500-1000 μm, 1000-2000 μm and > 2000 μm) during three cruises carried out in the open NW Mediterranean Sea. We assessed their metabolic rates from empirical published relationships and estimated the active fluxes of dissolved carbon to the mesopelagic zone driven by migrant zooplankton. Within the predominantly oligotrophic Mediterranean Sea, the NW region is one of the most productive ones, with a seasonal cycle characterized by a prominent spring bloom. The study area was visited at three different phases of the seasonal cycle: during the spring bloom, the post-bloom, and strongly stratified oligotrophic conditions. We found seasonal differences in DVM, less evident during the bloom. Changes in DVM intensity were related to the composition of the zooplanktonic assemblage, which also varied between cruises. Euphausiids appeared as the most active migrants in all seasons, and their life cycle conditioned the observed pattern. Immature stages, which are unable to perform large diel vertical movements, dominated during the bloom, in contrast to the higher relative importance of migrating adults in the other two sampling periods. The amount of dissolved carbon exported was determined by the migrant zooplankton biomass, being highest during the post-bloom (2.2 mmol C respired m- 2 d- 1, and up to 3.1 mmol C exported m- 2 d- 1 when DOC release estimations are added). The active transport by diel migrants represented a substantial contribution to total carbon export to deep waters, especially under stratified oligotrophic conditions, revealing the importance of zooplankton in the biological pump operating in the study area.

Dissolved Organic Matter (DOM) Export from Watersheds to Coastal Oceans

NASA Astrophysics Data System (ADS)

Chen, R. F.; Gardner, G. B.; Peri, F.

2016-02-01

Dissolved organic matter (DOM) from terrestrial plants and soils is transported by surface waters and groundwaters to coastal ocean waters. Along the way, photochemical and biological degradation can remove DOM, and in situ processes such as phytoplankton leaching and sediment sources can add to the DOM in the river water. Wetlands, especially coastal wetlands can add significant amounts of DOM that is carried by rivers and is exported through estuaries to coastal systems. We will present observational data from a variety of coastal systems (San Francisco Bay, Boston Harbor, Chesapeake Bay, Hudson River, the Mississippi River, and a small salt marsh in the Gulf of Mexico). High resolution measurements of chromophoric dissolved organic matter (CDOM) can be correlated with dissolved organic carbon (DOC) so can be used to estimate DOC in specific systems and seasons. Gradients in CDOM/DOC combined with water fluxes can be used to estimate DOC fluxes from a variety of coastal watersheds to coastal systems. Influences of land use, system size, residence time, DOM quality, and photochemical and biological degradation will be discussed. The significance of coastal wetlands in the land-to-ocean export of DOC will be emphasized.

Small-angle X-Ray analysis of macromolecular structure: the structure of protein NS2 (NEP) in solution

NASA Astrophysics Data System (ADS)

Shtykova, E. V.; Bogacheva, E. N.; Dadinova, L. A.; Jeffries, C. M.; Fedorova, N. V.; Golovko, A. O.; Baratova, L. A.; Batishchev, O. V.

2017-11-01

A complex structural analysis of nuclear export protein NS2 (NEP) of influenza virus A has been performed using bioinformatics predictive methods and small-angle X-ray scattering data. The behavior of NEP molecules in a solution (their aggregation, oligomerization, and dissociation, depending on the buffer composition) has been investigated. It was shown that stable associates are formed even in a conventional aqueous salt solution at physiological pH value. For the first time we have managed to get NEP dimers in solution, to analyze their structure, and to compare the models obtained using the method of the molecular tectonics with the spatial protein structure predicted by us using the bioinformatics methods. The results of the study provide a new insight into the structural features of nuclear export protein NS2 (NEP) of the influenza virus A, which is very important for viral infection development.

Cooling molten salt reactors using "gas-lift"

NASA Astrophysics Data System (ADS)

Zitek, Pavel; Valenta, Vaclav; Klimko, Marek

2014-08-01

This study briefly describes the selection of a type of two-phase flow, suitable for intensifying the natural flow of nuclear reactors with liquid fuel - cooling mixture molten salts and the description of a "Two-phase flow demonstrator" (TFD) used for experimental study of the "gas-lift" system and its influence on the support of natural convection. The measuring device and the application of the TDF device is described. The work serves as a model system for "gas-lift" (replacing the classic pump in the primary circuit) for high temperature MSR planned for hydrogen production. An experimental facility was proposed on the basis of which is currently being built an experimental loop containing the generator, separator bubbles and necessary accessories. This loop will model the removal of gaseous fission products and tritium. The cleaning of the fuel mixture of fluoride salts eliminates problems from Xenon poisoning in classical reactors.

The simulated climate of the Last Glacial Maximum and insights into the global marine carbon cycle

NASA Astrophysics Data System (ADS)

Buchanan, Pearse J.; Matear, Richard J.; Lenton, Andrew; Phipps, Steven J.; Chase, Zanna; Etheridge, David M.

2016-12-01

The ocean's ability to store large quantities of carbon, combined with the millennial longevity over which this reservoir is overturned, has implicated the ocean as a key driver of glacial-interglacial climates. However, the combination of processes that cause an accumulation of carbon within the ocean during glacial periods is still under debate. Here we present simulations of the Last Glacial Maximum (LGM) using the CSIRO Mk3L-COAL (Carbon-Ocean-Atmosphere-Land) earth system model to test the contribution of physical and biogeochemical processes to ocean carbon storage. For the LGM simulation, we find a significant global cooling of the surface ocean (3.2 °C) and the expansion of both minimum and maximum sea ice cover broadly consistent with proxy reconstructions. The glacial ocean stores an additional 267 Pg C in the deep ocean relative to the pre-industrial (PI) simulation due to stronger Antarctic Bottom Water formation. However, 889 Pg C is lost from the upper ocean via equilibration with a lower atmospheric CO2 concentration and a global decrease in export production, causing a net loss of carbon relative to the PI ocean. The LGM deep ocean also experiences an oxygenation ( > 100 mmol O2 m-3) and deepening of the calcite saturation horizon (exceeds the ocean bottom) at odds with proxy reconstructions. With modifications to key biogeochemical processes, which include an increased export of organic matter due to a simulated release from iron limitation, a deepening of remineralisation and decreased inorganic carbon export driven by cooler temperatures, we find that the carbon content of the glacial ocean can be sufficiently increased (317 Pg C) to explain the reduction in atmospheric and terrestrial carbon at the LGM (194 ± 2 and 330 ± 400 Pg C, respectively). Assuming an LGM-PI difference of 95 ppm pCO2, we find that 55 ppm can be attributed to the biological pump, 28 ppm to circulation changes and the remaining 12 ppm to solubility. The biogeochemical modifications also improve model-proxy agreement in export production, carbonate chemistry and dissolved oxygen fields. Thus, we find strong evidence that variations in the oceanic biological pump exert a primary control on the climate.

The Influence of Water Circulation on Dissolved Organic Matter Dynamics in Bald Head Creek

NASA Astrophysics Data System (ADS)

Lebrasse, M. C.; Osburn, C. L.; Bohnenstiehl, D. R.; He, R.

2016-12-01

Dissolved organic matter (DOM) plays an important role in biogeochemical cycles in estuaries such as tidal creeks draining coastal wetlands such as salt marshes. However, significant knowledge gaps remain regarding the quantity and quality of the DOM that tidally exchanges between salt marshes and their adjacent estuaries. Tidal movements play a central role in lateral exchanges of materials and bidirectional flow results in the mixing of DOM from marsh plants and estuarine DOM. The aim of this study was to better understand the role of water circulation on the distribution and quality of DOM in Bald Head Creek, a tributary to the Cape Fear River estuary in eastern North Carolina. Dissolved organic carbon (DOC) concentration, stable carbon isotopes, and chromophoric DOM (CDOM) absorbance at 254 nm (a254) were used to distinguish between DOM quantity and quality at three locations along the creek: Site 3 (upstream), Site 2 (middle stream), and Site 1 (near the creek mouth). Samples were collected over four tidal cycles between March-August 2016 and compared to time series data collected approximately weekly from 2014-2016. DOM characteristics differed substantially over the tidal cycle. Higher CDOM and DOC concentration were observed at low tide than at high tide at all three sites, suggesting greater export of carbon from the marsh into the creek as the tides recede. Analysis of CDOM quality based on specific UV absorbance at 254 nm (SUVA254) and spectral slope ratio (SR) showed that the marsh end-member (Site 3) source of DOM had greater aromaticity and higher molecular weight. Site 1 showed greater variability over the tidal cycle most likely due to a greater tidal influence, being closer to the mouth. Additionally, an unmanned surface vehicle (USV) and a hydrodynamic model were used to map water circulation and DOC concentration along the creek to compute exchanges with the adjacent estuary. Results suggest that estuarine OM dynamics are strongly controlled by the circulation of water, especially for tidal creeks where tidal pumping can dominate lateral fluxes of DOM to adjacent waters.

A feedback regulatory model for RifQ-mediated repression of rifamycin export in Amycolatopsis mediterranei.

PubMed

Lei, Chao; Wang, Jingzhi; Liu, Yuanyuan; Liu, Xinqiang; Zhao, Guoping; Wang, Jin

2018-01-29

Due to the important role of rifamycin in curing tuberculosis infection, the study on rifamycin has never been stopped. Although RifZ, which locates within the rifamycin biosynthetic cluster, has recently been characterized as a pathway-specific regulator for rifamycin biosynthesis, little is known about the regulation of rifamycin export. In this work, we proved that the expression of the rifamycin efflux pump (RifP) was regulated by RifQ, a TetR-family transcriptional regulator. Deletion of rifQ had little impact on bacterial growth, but resulted in improved rifamycin production, which was consistent with the reverse transcription PCR results that RifQ negatively regulated rifP's transcription. With electrophoretic mobility shift assay and DNase I Footprinting assay, RifQ was found to directly bind to the promoter region of rifP, and a typical inverted repeat was identified within the RifQ-protected sequences. The transcription initiation site of rifP was further characterized and found to be upstream of the RifQ binding sites, well explaining the RifQ-mediated repression of rifP's transcription in vivo. Moreover, rifamycin B (the end product of rifamycin biosynthesis) remarkably decreased the DNA binding affinity of RifQ, which led to derepression of rifamycin export, reducing the intracellular concentration of rifamycin B as well as its toxicity against the host. Here, we proved that the export of rifamycin B was repressed by RifQ in Amycolatopsis mediterranei, and the RifQ-mediated repression could be specifically relieved by rifamycin B, the end product of rifamycin biosynthesis, based on which a feedback model was proposed for regulation of rifamycin export. With the findings here, one could improve the antibiotic yield by simply inactivating the negative regulator of the antibiotic transporter.

Amazon River carbon dioxide outgassing fuelled by wetlands.

PubMed

Abril, Gwenaël; Martinez, Jean-Michel; Artigas, L Felipe; Moreira-Turcq, Patricia; Benedetti, Marc F; Vidal, Luciana; Meziane, Tarik; Kim, Jung-Hyun; Bernardes, Marcelo C; Savoye, Nicolas; Deborde, Jonathan; Souza, Edivaldo Lima; Albéric, Patrick; Landim de Souza, Marcelo F; Roland, Fabio

2014-01-16

River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters.

Balanced sediment fluxes in southern California’s Mediterranean-climate zone salt marshes

USGS Publications Warehouse

Rosencranz, Jordan A.; Ganju, Neil K.; Ambrose, Richard F.; Brosnahan, Sandra M.; Dickhudt, Patrick J.; Guntenspergen, Glenn R.; MacDonald, Glen M.; Takekawa, John Y.; Thorne, Karen M.

2016-01-01

Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many Mediterranean-climate salt marshes along southern California, USA coast import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are potentially important for marsh stability. We calculated tidal creek sediment fluxes within a highly modified, sediment-starved, 1.5-km2 salt marsh (Seal Beach) and a less modified 1-km2marsh (Mugu) with fluvial sediment supply. We measured salt marsh plain suspended sediment concentration and vertical accretion using single stage samplers and marker horizons. At Seal Beach, a 2014 storm yielded 39 and 28 g/s mean sediment fluxes and imported 12,000 and 8800 kg in a western and eastern channel. Western channel storm imports offset 8700 kg exported during 2 months of dry weather, while eastern channel storm imports augmented 9200 kg imported during dry weather. During the storm at Mugu, suspended sediment concentrations on the marsh plain increased by a factor of four; accretion was 1–2 mm near creek levees. An exceptionally high tide sequence yielded 4.4 g/s mean sediment flux, importing 1700 kg: 20 % of Mugu’s dry weather fluxes. Overall, low sediment fluxes were observed, suggesting that these salt marshes are geomorphically stable during dry weather conditions. Results suggest storms and high lunar tides may play large roles, importing sediment and maintaining dry weather sediment flux balances for southern California salt marshes. However, under future climate change and sea level rise scenarios, results suggest that balanced sediment fluxes lead to marsh elevational instability based on estimated mineral sediment deficits.

Estimates of Gelatinous Zooplankton Carbon Flux in the Global Oceans

NASA Astrophysics Data System (ADS)

Luo, J. Y.; Condon, R.; Cowen, R. K.

2016-02-01

Gelatinous zooplankton (GZ), which include the cnidarians, ctenophores, and pelagic tunicates, are a common feature of marine ecosystems worldwide, but their contribution to global biogeochemical fluxes has never been assessed. We constructed a carbon-cycle model with a single, annual time-step and resolved to a 5° spatial grid for the three major GZ groups in order to evaluate the GZ-mediated carbon fluxes and export to depth. Biomass inputs (totaling 0.149 Pg C) were based off of Lucas et al. (2014) and updated using the JeDI database (Condon et al. 2015). From the upper ocean, biomass export flux from cnidarians, ctenophores, and tunicates totaled 2.96 ± 2.82 Pg C y-1, though only 0.199 ± 0.023 Pg C y-1 of GZ carbon were transferred to upper trophic levels, roughly amounting to one-quarter of all mesozooplankton production flux. In contrast, GZ fluxes to DOC only comprised ca. 2% of labile DOC flux. Egestion flux from the upper ocean totaled 2.56 ± 3.35 Pg C y-1, with over 80% being fast-sinking tunicate fecal pellets. Due to fast sinking rates of carcasses and fecal pellets, 26% of all C export from the upper ocean reached the seafloor, such that GZ fecal matter is estimated to comprise between 20-30% of global POC surface export and 11-30% of POC seafloor deposition. Finally, results from sensitivity analyses showed no increase in cnidarian and ctenophore export fluxes with increased temperature and jelly biomass, though tunicate export fluxes showed some increase with both temperature and biomass. These results suggest that current estimates of global POC flux from the surface oceans, which range between 8.6 - 12.9 Pg C y-1, may be underestimated by as much as 20 - 25%, implying a definite need to incorporate GZ mediated flux in estimating the biological pump transfer efficiency. Our study represents the first effort to quantify the role of gelatinous zooplankton in the global marine carbon cycle.

Development of High-Temperature Transport Technologies of Molten Salt Slurry in Pyrometallurgical Reprocessing

NASA Astrophysics Data System (ADS)

Hijikata, Takatoshi; Koyama, Tadafumi

Pyrometallurgical-reprocessing is one of the most promising technologies for advanced fuel cycle with favorable economic potential and intrinsic proliferation resistance. The development of transport technology for molten salt is a key issue in the industrialization of pyro-reprocessing. As for pure molten LiCl-KCl eutectic salt at approximately 773 K, we have already reported the successful results of transport using gravity and a centrifugal pump. However, molten salt in an electrorefiner mixes with insoluble fines when spent fuel is dissolved in porous anode basket. The insoluble consists of noble metal fission products, such as Pd, Ru, Mo, and Zr. There have been very few transport studies of a molten salt slurry (metal fines-molten salt mixture). Hence, transport experiments on a molten salt slurry were carried out to investigate the behavior of the slurry in a tube. The apparatus used in the transport experiments on the molten salt slurry consisted of a supply tank, a 10° inclined transport tube (10 mm inner diameter), a valve, a filter, and a recovery tank. Stainless steel (SS) fines with diameters from 53 to 415 μm were used. To disperse these fines homogenously, the molten salt and fines were stirred in the supply tank by an impeller at speeds from 1200 to 2100 rpm. The molten salt slurry containing 0.04 to 0.4 vol.% SS fines was transported from the supply tank to the recovery tank through the transportation tube. In the recovery tank, the fines were separated from the molten salt by the filter to measure the transport behavior of molten salt and SS fines. When the velocity of the slurry was 0.02 m/s, only 1% of the fines were transported to the recovery tank. On the other hand, most of the fines were transported when the velocity of the slurry was more than 0.8 m/s. Consequently, the molten salt slurry can be transported when the velocity is more than 0.8 m/s.

Importance of salt fingering for new nitrogen supply in the oligotrophic ocean.

PubMed

Fernández-Castro, B; Mouriño-Carballido, B; Marañón, E; Chouciño, P; Gago, J; Ramírez, T; Vidal, M; Bode, A; Blasco, D; Royer, S-J; Estrada, M; Simó, R

2015-09-09

The input of new nitrogen into the euphotic zone constrains the export of organic carbon to the deep ocean and thereby the biologically mediated long-term CO2 exchange between the ocean and atmosphere. In low-latitude open-ocean regions, turbulence-driven nitrate diffusion from the ocean's interior and biological fixation of atmospheric N2 are the main sources of new nitrogen for phytoplankton productivity. With measurements across the tropical and subtropical Atlantic, Pacific and Indian oceans, we show that nitrate diffusion (171±190 μmol m(-2) d(-1)) dominates over N2 fixation (9.0±9.4 μmol m(-2) d(-1)) at the time of sampling. Nitrate diffusion mediated by salt fingers is responsible for ca. 20% of the new nitrogen supply in several provinces of the Atlantic and Indian Oceans. Our results indicate that salt finger diffusion should be considered in present and future ocean nitrogen budgets, as it could supply globally 0.23-1.00 Tmol N yr(-1) to the euphotic zone.

Bathymetric map of the south part of Great Salt Lake, Utah, 2005

USGS Publications Warehouse

Baskin, Robert L.; Allen, David V.

2005-01-01

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Wildlife Resources, collected bathymetric data for the south part of Great Salt Lake during 2002–04 using a single beam, high-definition fathometer and real-time differential global positioning system. Approximately 7.6 million depth readings were collected along more than 1,050 miles of survey transects for construction of this map. Sound velocities were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed with commercial hydrographic software and exported into geographic information system (GIS) software for mapping. Because of the shallow nature of the lake and the limitations of the instrumentation, contours above an altitude of 4,193 feet were digitized from existing USGS 1:24,000 source-scale digital line graph data.For additional information on methods used to derive the bathymetric contours for this map, please see Baskin, Robert L., 2005, Calculation of area and volume for the south part of Great Salt Lake, Utah, U.S. Geological Survey Open-File Report OFR–2005–1327.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagstaff, W.

The headquarters building for the Church of Jesus Christ of Latter-Day Saints (LDS) is a 28-story office building in downtown Salt Lake City, Utah. Completed in 1972, the building is heated and cooled by ground-water heat pumps. The heat-pump system allows considerable flexibility in balancing heating and cooling requirements, and allows for the recovery and use of heat which otherwise would be lost. Although there are a few problems associated with the system, officials in the Operations and Maintenance Division express general satisfaction with it and with the equipment. No firm figures are available on the economics of the heat-pumpmore » system, but it appears to be more economic than a comparable conventional system.« less

Value, Market Preferences and Trade of Beche-De-Mer from Pacific Island Sea Cucumbers

PubMed Central

Purcell, Steven W.

2014-01-01

Market preferences of natural resources contribute to shape their exploitation and production. Beche-de-mer, the product after gutting, cooking, salting and drying sea cucumbers, is exported worldwide to Asian dried seafood markets. A better understanding of the trade, value and market preferences of Pacific island beche-de-mer could identify critical postharvest processing techniques and management strategies for fisheries and aquaculture. Data were collected on export prices and trade of beche-de-mer from Kiribati, Fiji, Tonga and New Caledonia, and the selling prices, respective sizes and organoleptic properties of the products in stores in China. Export prices varied considerably within and among the four countries and low-value species were the most exported by volume. Most of the beche-de-mer from the four Pacific islands is exported to Hong Kong, where quality products are sold and others are distributed to mainland China. Prices of the beche-de-mer in Chinese stores varied up to ten-fold and were mostly influenced by species, body size and, to a lesser extent, physical damage to the products. Market prices across species (averaging US$15–385 kg−1) appear to have mostly increased six- to twelve-fold over the past decade. The data allude that fisheries for Holothuria scabra, H. lessoni, H. fuscogilva, H. whitmaei and Thelenota ananas should be most carefully managed because they were the highest-value species and under greatest demand. The relationships between size of beche-de-mer and sale price were species specific and highly varied. This study also highlights the need for better regulations and/or enforcement of minimum size limits in sea cucumber fisheries, which can help to maximise economic benefits of wild stocks. PMID:24736374

Value, market preferences and trade of Beche-de-mer from Pacific Island sea cucumbers.

PubMed

Purcell, Steven W

2014-01-01

Market preferences of natural resources contribute to shape their exploitation and production. Beche-de-mer, the product after gutting, cooking, salting and drying sea cucumbers, is exported worldwide to Asian dried seafood markets. A better understanding of the trade, value and market preferences of Pacific island beche-de-mer could identify critical postharvest processing techniques and management strategies for fisheries and aquaculture. Data were collected on export prices and trade of beche-de-mer from Kiribati, Fiji, Tonga and New Caledonia, and the selling prices, respective sizes and organoleptic properties of the products in stores in China. Export prices varied considerably within and among the four countries and low-value species were the most exported by volume. Most of the beche-de-mer from the four Pacific islands is exported to Hong Kong, where quality products are sold and others are distributed to mainland China. Prices of the beche-de-mer in Chinese stores varied up to ten-fold and were mostly influenced by species, body size and, to a lesser extent, physical damage to the products. Market prices across species (averaging US$15-385 kg-1) appear to have mostly increased six- to twelve-fold over the past decade. The data allude that fisheries for Holothuria scabra, H. lessoni, H. fuscogilva, H. whitmaei and Thelenota ananas should be most carefully managed because they were the highest-value species and under greatest demand. The relationships between size of beche-de-mer and sale price were species specific and highly varied. This study also highlights the need for better regulations and/or enforcement of minimum size limits in sea cucumber fisheries, which can help to maximise economic benefits of wild stocks.

Modeling interannual dense shelf water export in the region of the Mertz Glacier Tongue (1992-2007)

NASA Astrophysics Data System (ADS)

Cougnon, E. A.; Galton-Fenzi, B. K.; Meijers, A. J. S.; Legrésy, B.

2013-10-01

Ocean observations around the Australian-Antarctic basin show the importance of coastal latent heat polynyas near the Mertz Glacier Tongue (MGT) to the formation of Dense Shelf Water (DSW) and associated Antarctic Bottom Water (AABW). Here, we use a regional ocean/ice shelf model to investigate the interannual variability of the export of DSW from the Adélie (west of the MGT) and the Mertz (east of the MGT) depressions from 1992 to 2007. The variability in the model is driven by changes in observed surface heat and salt fluxes. The model simulates an annual mean export of DSW through the Adélie sill of about 0.07 ± 0.06 Sv. From 1992 to 1998, the export of DSW through the Adélie (Mertz) sills peaked at 0.14 Sv (0.29 Sv) during July to November. During periods of mean to strong polynya activity (defined by the surface ocean heat loss), DSW formed in the Adélie depression can spread into the Mertz depression via the cavity under the MGT. An additional simulation, where ocean/ice shelf thermodynamics have been disabled, highlights the fact that models without ocean/ice shelf interaction processes will significantly overestimate rates of DSW export. The melt rates of the MGT are 1.2 ± 0.4 m yr-1 during periods of average to strong polynya activity and can increase to 3.8 ± 1.5 m/yr during periods of sustained weak polynya activity, due to the increased presence of relatively warmer water interacting with the base of the ice shelf. The increased melting of the MGT during a weak polynya state can cause further freshening of the DSW and ultimately limits the production of AABW.

Effects of flow diversions on water and habitat quality: Examples from California's highly manipulated Sacramento–San Joaquin Delta

USGS Publications Warehouse

Monsen, Nancy E.; Cloern, James E.; Burau, Jon R.

2007-01-01

We use selected monitoring data to illustrate how localized water diversions from seasonal barriers, gate operations, and export pumps alter water quality across the Sacramento-San Joaquin Delta (California). Dynamics of water-quality variability are complex because the Delta is a mixing zone of water from the Sacramento and San Joaquin Rivers, agricultural return water, and the San Francisco Estuary. Each source has distinct water-quality characteristics, and the contribution of each source varies in response to natural hydrologic variability and water diversions. We use simulations with a tidal hydrodynamic model to reveal how three diversion events, as case studies, influence water quality through their alteration of Delta-wide water circulation patterns and flushing time. Reduction of export pumping decreases the proportion of Sacramento- to San Joaquin-derived fresh water in the central Delta, leading to rapid increases in salinity. Delta Cross Channel gate operations control salinity in the western Delta and alter the freshwater source distribution in the central Delta. Removal of the head of Old River barrier, in autumn, increases the flushing time of the Stockton Ship Channel from days to weeks, contributing to a depletion of dissolved oxygen. Each shift in water quality has implications either for habitat quality or municipal drinking water, illustrating the importance of a systems view to anticipate the suite of changes induced by flow manipulations, and to minimize the conflicts inherent in allocations of scarce resources to meet multiple objectives.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Aijie, E-mail: zhangaijie1986@163.com

Alpha-naphthylisothiocyanate (ANIT) is a toxicant that is widely used in rodents to model human intrahepatic cholestasis. The aim of the study is to investigate whether effects of dioscin on ANIT-induced cholestasis are related to changes in expression of hepatic transporters in rats. Effects of dioscin on cholestasis were examined by histology and biochemical marker levels. The functional changes of hepatic transporters were determined by in vitro, in situ and in vivo. qRT-PCR and western blot were used to assess the expression of hepatic transporters in cholestatic rats. Dioscin administration could ameliorate cholestasis, as evidenced by reduced biochemical markers as wellmore » as improved liver pathology. The uptakes of organic anion transporting polypeptide (Oatp) substrates were altered in liver uptake index in vivo, perfused rat liver in situ and isolated rat hepatocytes in vitro in cholestasis rats. qRT-PCR and western blot analysis indicated co-treatment of ANIT with dioscin prevented the adaptive down-regulation of Oatp1a1, 1b2, and prompted the up-regulation of Oatp1a4, multidrug resistance-associated protein (Mrp) 2 and bile salt export pump (Bsep). In addition, concerted effects on Mrp2 and Bsep occurred through up-regulation of small heterodimer partner by activating farnesoid X receptor. Dioscin might prevent impairment of hepatic function by restoring hepatic transporter expression. - Highlights: • Cholestasis was improved by dioscin via up-regulating the expression of Oatps, Mrp2 and Bsep. • Dioscin regulated Mrp2 and Bsep via activating FXR. • Dioscin may be a candidate drug for the prevention of intrahepatic cholestasis.« less

The inhibition of hepatic bile acids transporters Ntcp and Bsep is involved in the pathogenesis of isoniazid/rifampicin-induced hepatotoxicity.

PubMed

Guo, Yao Xue; Xu, Xue Fei; Zhang, Qi Zhi; Li, Chun; Deng, Ye; Jiang, Pei; He, Lei Yan; Peng, Wen Xing

2015-01-01

Co-treatment of isoniazid (INH) and rifampicin (RFP) is well known for clinically apparent liver injury. However, the mechanism of INH/RFP-induced liver injury is controversial. Emerging evidence shows links between inhibition of bile acids transporters and drug-induced liver injury (DILI). The present study investigates whether sodium taurocholate cotransporting polypeptide (NTCP/Ntcp; SLC10A1) and bile salt export pump (BSEP/Bsep; ABCB11) are involved in the anti-tuberculosis medicines induced liver injury. ICR female mice were intragastrically treated with INH (50 or 100 mg/kg), RFP (100 or 200 mg/kg), or the combination of INH/RFP (50 + 100 mg/kg or 100 + 200 mg/kg) for 14 consecutive days. Liver histopathological examination, serum biochemical and liver malondialdehyde tests were evaluated. Apparent histopathological alterations and hepatic oxidative stress showed in INH (100 mg/kg), RFP (200 mg/kg) and their combination group. The hepatoxic effect was also indicated by increased serum biomarkers, such as aspartate transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), direct bilirubin (DBil), total bilirubin (TBil) and total bile acids (TBA). Both doses of INH/RFP administration significantly down-regulated the expression of Ntcp and Bsep in liver. Furthermore, the combination of INH and RFP displayed stronger effect on the expression of Ntcp compared with the corresponding dose of INH or RFP alone. In conclusion, down-regulated expression of hepatic Ntcp and Bsep might play an important role in the development of INH and RFP induced liver injury.

Defective canalicular transport and toxicity of dietary ursodeoxycholic acid in the abcb11-/- mouse: transport and gene expression studies.

PubMed

Wang, Renxue; Liu, Lin; Sheps, Jonathan A; Forrest, Dana; Hofmann, Alan F; Hagey, Lee R; Ling, Victor

2013-08-15

The bile salt export pump (BSEP), encoded by the abcb11 gene, is the major canalicular transporter of bile acids from the hepatocyte. BSEP malfunction in humans causes bile acid retention and progressive liver injury, ultimately leading to end-stage liver failure. The natural, hydrophilic, bile acid ursodeoxycholic acid (UDCA) is efficacious in the treatment of cholestatic conditions, such as primary biliary cirrhosis and cholestasis of pregnancy. The beneficial effects of UDCA include promoting bile flow, reducing hepatic inflammation, preventing apoptosis, and maintaining mitochondrial integrity in hepatocytes. However, the role of BSEP in mediating UDCA efficacy is not known. Here, we used abcb11 knockout mice (abcb11-/-) to test the effects of acute and chronic UDCA administration on biliary secretion, bile acid composition, liver histology, and liver gene expression. Acutely infused UDCA, or its taurine conjugate (TUDC), was taken up by the liver but retained, with negligible biliary output, in abcb11-/- mice. Feeding UDCA to abcb11-/- mice led to weight loss, retention of bile acids, elevated liver enzymes, and histological damage to the liver. Semiquantitative RT-PCR showed that genes encoding Mdr1a and Mdr1b (canalicular) as well as Mrp4 (basolateral) transporters were upregulated in abcb11-/- mice. We concluded that infusion of UDCA and TUDC failed to induce bile flow in abcb11-/- mice. UDCA fed to abcb11-/- mice caused liver damage and the appearance of biliary tetra- and penta-hydroxy bile acids. Supplementation with UDCA in the absence of Bsep caused adverse effects in abcb11-/- mice.

Stress Introduction Rate Alters the Benefit of AcrAB-TolC Efflux Pumps.

PubMed

Langevin, Ariel M; Dunlop, Mary J

2018-01-01

Stress tolerance studies are typically conducted in an all-or-none fashion. However, in realistic settings-such as in clinical or metabolic engineering applications-cells may encounter stresses at different rates. Therefore, how cells tolerate stress may depend on its rate of appearance. To address this, we studied how the rate of stress introduction affects bacterial stress tolerance by focusing on a key stress response mechanism. Efflux pumps, such as AcrAB-TolC of Escherichia coli , are membrane transporters well known for the ability to export a wide variety of substrates, including antibiotics, signaling molecules, and biofuels. Although efflux pumps improve stress tolerance, pump overexpression can result in a substantial fitness cost to the cells. We hypothesized that the ideal pump expression level would involve a rate-dependent trade-off between the benefit of pumps and the cost of their expression. To test this, we evaluated the benefit of the AcrAB-TolC pump under different rates of stress introduction, including a step, a fast ramp, and a gradual ramp. Using two chemically diverse stresses, the antibiotic chloramphenicol and the jet biofuel precursor pinene, we assessed the benefit provided by the pumps. A mathematical model describing these effects predicted the benefit as a function of the rate of stress introduction. Our findings demonstrate that as the rate of introduction is lowered, stress response mechanisms provide a disproportionate benefit to pump-containing strains, allowing cells to survive beyond the original inhibitory concentrations. IMPORTANCE Efflux pumps are ubiquitous in nature and provide stress tolerance in the cells of species ranging from bacteria to mammals. Understanding how pumps provide tolerance has far-reaching implications for diverse fields, from medicine to biotechnology. Here, we investigated how the rate of stressor appearance impacts tolerance. We focused on two distinct substrates of AcrAB-TolC efflux pumps, the antibiotic chloramphenicol and the biofuel precursor pinene. Interestingly, tolerance is highly dependent on the rate of stress introduction. Therefore, it is important to consider not only the total quantity of a stressor but also the rate at which it is applied. The implications of this work are significant because environments are rarely static; antibiotic concentrations change during dosing, and metabolic engineering processes change with time. Copyright © 2017 American Society for Microbiology.

An alternative arrangement of metered dosing fluid using centrifugal pump

NASA Astrophysics Data System (ADS)

Islam, Md. Arafat; Ehsan, Md.

2017-06-01

Positive displacement dosing pumps are extensively used in various types of process industries. They are widely used for metering small flow rates of a dosing fluid into a main flow. High head and low controllable flow rates make these pumps suitable for industrial flow metering applications. However their pulsating flow is not very suitable for proper mixing of fluids and they are relatively more expensive to buy and maintain. Considering such problems, alternative techniques to control the fluid flow from a low cost centrifugal pump is practiced. These include - throttling, variable speed drive, impeller geometry control and bypass control. Variable speed drive and impeller geometry control are comparatively costly and the flow control by throttling is not an energy efficient process. In this study an arrangement of metered dosing flow was developed using a typical low cost centrifugal pump using bypass flow technique. Using bypass flow control technique a wide range of metered dosing flows under a range of heads were attained using fixed pump geometry and drive speed. The bulk flow returning from the system into the main tank ensures better mixing which may eliminate the need of separate agitators. Comparative performance study was made between the bypass flow control arrangement of centrifugal pump and a diaphragm type dosing pump. Similar heads and flow rates were attainable using the bypass control system compared to the diaphragm dosing pump, but using relatively more energy. Geometrical optimization of the centrifugal pump impeller was further carried out to make the bypass flow arrangement more energy efficient. Although both the systems run at low overall efficiencies but the capital cost could be reduced by about 87% compared to the dosing pump. The savings in capital investment and lower maintenance cost very significantly exceeds the relatively higher energy cost of the bypass system. This technique can be used as a cost effective solution for industries in Bangladesh and have been implemented in two salt iodization plants at Narayangang.

An Experimental Test Facility to Support Development of the Fluoride Salt Cooled High Temperature Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoder Jr, Graydon L; Aaron, Adam M; Cunningham, Richard Burns

2014-01-01

The need for high-temperature (greater than 600 C) energy exchange and delivery systems is significantly increasing as the world strives to improve energy efficiency and develop alternatives to petroleum-based fuels. Liquid fluoride salts are one of the few energy transport fluids that have the capability of operating at high temperatures in combination with low system pressures. The Fluoride Salt-Cooled High-Temperature Reactor design uses fluoride salt to remove core heat and interface with a power conversion system. Although a significant amount of experimentation has been performed with these salts, specific aspects of this reactor concept will require experimental confirmation during themore » development process. The experimental facility described here has been constructed to support the development of the Fluoride Salt Cooled High Temperature Reactor concept. The facility is capable of operating at up to 700 C and incorporates a centrifugal pump to circulate FLiNaK salt through a removable test section. A unique inductive heating technique is used to apply heat to the test section, allowing heat transfer testing to be performed. An air-cooled heat exchanger removes added heat. Supporting loop infrastructure includes a pressure control system; trace heating system; and a complement of instrumentation to measure salt flow, temperatures, and pressures around the loop. The initial experiment is aimed at measuring fluoride salt heat transfer inside a heated pebble bed similar to that used for the core of the pebble bed advanced high-temperature reactor. This document describes the details of the loop design, auxiliary systems used to support the facility, the inductive heating system, and facility capabilities.« less

ET-1 increases reactive oxygen species following hypoxia and high-salt diet in the mouse glomerulus.

PubMed

Heimlich, J B; Speed, J S; Bloom, C J; O'Connor, P M; Pollock, J S; Pollock, D M

2015-03-01

This study was designed to determine whether ET-1 derived from endothelial cells contributes to oxidative stress in the glomerulus of mice subjected to a high-salt diet and/or hypoxia. C57BL6/J control mice or vascular endothelial cell ET-1 knockout (VEET KO) mice were subjected to 3-h exposure to hypoxia (8% O₂) and/or 2 weeks of high-salt diet (4% NaCl) prior to metabolic cage assessment of renal function and isolation of glomeruli for the determination of reactive oxygen species (ROS). In control mice, hypoxia significantly increased urinary protein excretion during the initial 24 h, but only in animals on a high-salt diet. Hypoxia increased glomerular ET-1 mRNA expression in control, but not in vascular endothelial cell ET-1 knockout (VEET KO) mice. Under normoxic conditions, mice on a high-salt diet had approx. 150% higher glomerular ET-1 mRNA expression compared with a normal-salt diet (P < 0.05). High-salt diet administration significantly increased glomerular ROS production in flox control, but not in glomeruli isolated from VEET KO mice. In C57BL6/J mice, the ETA receptor-selective antagonist, ABT-627, significantly attenuated the increase in glomerular ROS production produced by high-salt diet. In addition, chronic infusion of C57BL6/J mice with a subpressor dose of ET-1 (osmotic pumps) significantly increased the levels of glomerular ROS that were prevented by ETA antagonist treatment. These data suggest that both hypoxia and a high-salt diet increase glomerular ROS production via endothelial-derived ET-1-ETA receptor activation and provide a potential mechanism for ET-1-induced nephropathy. © 2014 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamburello, D; Richard Dimenna, R; Si Lee, S

2009-01-27

The transfer of liquid salt solution from Tank 32 to an evaporator is to be accomplished by activating the evaporator feed pump, with the supernate surface at a minimum height of approximately 74.4 inches above the sludge layer, while simultaneously turning on the downcomer with a flow rate of 110 gpm. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics (CFD) methods to determine the amount of entrained sludge solids pumped out of the tankmore » toward the evaporator with the downcomer turned on. The analysis results shows that, for the minimum tank liquid level of 105 inches above the tank bottom (which corresponds to a liquid depth of 74.4 inches above the sludge layer), the evaporator feed pump will contain less than 0.1 wt% sludge solids in the discharge stream, which is an order of magnitude less than the 1.0 wt% undissolved solids (UDS) loading criteria to feed the evaporator. Lower liquid levels with respect to the sludge layer will result in higher amounts of sludge entrainment due to the increased plunging jet velocity from the downcomer disturbing the sludge layer.« less

The Novel Mouse Mutation Oblivion Inactivates the PMCA2 Pump and Causes Progressive Hearing Loss

PubMed Central

de Angelis, Martin Hrabé; Fuchs, Helmut; Lim, Dmitry; Ortolano, Saida; Ingham, Neil J.; Brini, Marisa; Carafoli, Ernesto; Mammano, Fabio; Steel, Karen P.

2008-01-01

Progressive hearing loss is common in the human population, but we have few clues to the molecular basis. Mouse mutants with progressive hearing loss offer valuable insights, and ENU (N-ethyl-N-nitrosourea) mutagenesis is a useful way of generating models. We have characterised a new ENU-induced mouse mutant, Oblivion (allele symbol Obl), showing semi-dominant inheritance of hearing impairment. Obl/+ mutants showed increasing hearing impairment from post-natal day (P)20 to P90, and loss of auditory function was followed by a corresponding base to apex progression of hair cell degeneration. Obl/Obl mutants were small, showed severe vestibular dysfunction by 2 weeks of age, and were completely deaf from birth; sensory hair cells were completely degenerate in the basal turn of the cochlea, although hair cells appeared normal in the apex. We mapped the mutation to Chromosome 6. Mutation analysis of Atp2b2 showed a missense mutation (2630C→T) in exon 15, causing a serine to phenylalanine substitution (S877F) in transmembrane domain 6 of the PMCA2 pump, the resident Ca2+ pump of hair cell stereocilia. Transmembrane domain mutations in these pumps generally are believed to be incompatible with normal targeting of the protein to the plasma membrane. However, analyses of hair cells in cultured utricular maculae of Obl/Obl mice and of the mutant Obl pump in model cells showed that the protein was correctly targeted to the plasma membrane. Biochemical and biophysical characterisation showed that the pump had lost a significant portion of its non-stimulated Ca2+ exporting ability. These findings can explain the progressive loss of auditory function, and indicate the limits in our ability to predict mechanism from sequence alone. PMID:18974863

A single-component multidrug transporter of the major facilitator superfamily is part of a network that protects E scherichia coli from bile salt stress

PubMed Central

Paul, Stephanie; Alegre, Kamela O; Holdsworth, Scarlett R; Rice, Matthew; Brown, James A; McVeigh, Paul; Kelly, Sharon M; Law, Christopher J

2014-01-01

Resistance to high concentrations of bile salts in the human intestinal tract is vital for the survival of enteric bacteria such as E scherichia coli. Although the tripartite AcrAB–TolC efflux system plays a significant role in this resistance, it is purported that other efflux pumps must also be involved. We provide evidence from a comprehensive suite of experiments performed at two different pH values (7.2 and 6.0) that reflect pH conditions that E . coli may encounter in human gut that MdtM, a single-component multidrug resistance transporter of the major facilitator superfamily, functions in bile salt resistance in E . coli by catalysing secondary active transport of bile salts out of the cell cytoplasm. Furthermore, assays performed on a chromosomal ΔacrB mutant transformed with multicopy plasmid encoding MdtM suggested a functional synergism between the single-component MdtM transporter and the tripartite AcrAB–TolC system that results in a multiplicative effect on resistance. Substrate binding experiments performed on purified MdtM demonstrated that the transporter binds to cholate and deoxycholate with micromolar affinity, and transport assays performed on inverted vesicles confirmed the capacity of MdtM to catalyse electrogenic bile salt/H+ antiport. PMID:24684269

76 FR 33219 - Citric Acid and Certain Citrate Salts from the People's Republic of China: Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-08

...The Department of Commerce is conducting an administrative review of the countervailing duty order on citric acid and certain citrate salts from the People's Republic of China for the period September 19, 2008, through December 31, 2009. We preliminarily find that RZBC Co., Ltd. (``RZBC Co.''); RZBC Import & Export Co., Ltd. (``RZBC I&E''); RZBC (Juxian) Co., Ltd. (``RZBC Juxian''); and RZBC Group Co., Ltd. (``RZBC Group'') (collectively, ``RZBC''), and Yixing Union Biochemical Co., Ltd. (``Yixing Union Co.) and Yixing Union Cogeneration Co., Ltd. (``Cogeneration'') (collectively, ``Yixing Union'') received countervailable subsidies during the period of review. If these preliminary results are adopted in our final results of this review, we will instruct U.S. Customs and Border Protection to assess countervailing duties as detailed in the ``Preliminary Results of Review'' section of this notice. Interested parties are invited to comment on these preliminary results.

Deionization and desalination using electrostatic ion pumping

DOEpatents

Bourcier, William L.; Aines, Roger D.; Haslam, Jeffery J.; Schaldach, Charlene M.; O& #x27; Brien, Kevin C.; Cussler, Edward

2013-06-11

The present invention provides a new method and apparatus/system for purifying ionic solutions, such as, for example, desalinating water, using engineered charged surfaces to sorb ions from such solutions. Surface charge is applied externally, and is synchronized with oscillatory fluid movements between substantially parallel charged plates. Ions are held in place during fluid movement in one direction (because they are held in the electrical double layer), and released for transport during fluid movement in the opposite direction by removing the applied electric field. In this way the ions, such as salt, are "ratcheted" across the charged surface from the feed side to the concentrate side. The process itself is very simple and involves only pumps, charged surfaces, and manifolds for fluid collection.

Deionization and desalination using electrostatic ion pumping

DOEpatents

Bourcier, William L [Livermore, CA; Aines, Roger D [Livermore, CA; Haslam, Jeffery J [Livermore, CA; Schaldach, Charlene M [Pleasanton, CA; O'Brien, Kevin C [San Ramon, CA; Cussler, Edward [Edina, MN

2011-07-19

The present invention provides a new method and apparatus/system for purifying ionic solutions, such as, for example, desalinating water, using engineered charged surfaces to sorb ions from such solutions. Surface charge is applied externally, and is synchronized with oscillatory fluid movements between substantially parallel charged plates. Ions are held in place during fluid movement in one direction (because they are held in the electrical double layer), and released for transport during fluid movement in the opposite direction by removing the applied electric field. In this way the ions, such as salt, are "ratcheted" across the charged surface from the feed side to the concentrate side. The process itself is very simple and involves only pumps, charged surfaces, and manifolds for fluid collection.

Depleted uranium investigation at missile impact sites in White Sands Missile Range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Etten, D.M.; Purtymun, W.D.

1994-01-01

An investigation for residual depleted uranium was conducted at Pershing missile impact sites on the White Sands Missile Range. Subsurface core soil samples were taken at Chess, Salt Target, and Mine Impact Sites. A sampling pump was installed in a monitoring well at Site 65 where a Pershing earth penetrator was not recovered. Pumping tests and water samples were taken at this site. Chess Site, located in a gypsum flat, was the only location showing elevated levels of depleted uranium in the subsurface soil or perched groundwater. Small fragments can still be found on the surface of the impact sites.more » The seasonal flooding and near surface water has aided in the movement of surface fragments.« less

Mechanistic determinants of the directionality and energetics of active export by a heterodimeric ABC transporter

DOE PAGES

Grossmann, Nina; Vakkasoglu, Ahmet S.; Hulpke, Sabine; ...

2014-11-07

The ATP-binding cassette (ABC) transporter associated with antigen processing (TAP) participates in immune surveillance by moving proteasomal products into the endoplasmic reticulum (ER) lumen for major histocompatibility complex class I loading and cell surface presentation to cytotoxic T cells. Here we delineate the mechanistic basis for antigen translocation. Notably, TAP works as a molecular diode, translocating peptide substrates against the gradient in a strict unidirectional way. We reveal the importance of the D-loop at the dimer interface of the two nucleotide-binding domains (NBDs) in coupling substrate translocation with ATP hydrolysis and defining transport vectoriality. Substitution of the converved aspartate, whichmore » coordinates the ATP-binding site, decreases NBD dimerization affinity and turns the unidirectional primary active pump into a passive bidirectional nucleotide-gated facilitator. Thus, ATP hydrolysis is not required for translocation per se, but is essential for both active and unidirectional transport. As a result, our data provide detailed mechanistic insight into how heterodimeric ABC exporters operate.« less

Shallow Carbon Export from an Iron fertilised Plankton Bloom in the Southern Ocean

NASA Astrophysics Data System (ADS)

Sanders, R.; Pollard, R.; Morris, P.; Statham, P.; Moore, C. M. M.; Lucas, M.

2009-04-01

Some regions of the global ocean, notably the Southern Ocean, have high levels of macronutrients yet low levels of chlorophyll (the high nutrient, low chlorophyll or HNLC condition). Numerous artificial iron fertilization experiments conducted in the Southern Ocean have resulted in enhanced phytoplankton biomass and macronutrient drawdown. However the subsequent long-term biogeochemical consequences of such iron fertilization are unclear due in part to the limited size and duration of such experiments. An alternative way to assess the affect of iron over the Southern Ocean biological carbon pump is to observe the evolution of plankton production in regions of the Southern Ocean where shallow topography and Ocean currents interact to promote to release terrestrial iron into HNLC waters. During 2004-5 RRS Discovery conduced a complex programme of observations in such a region around the Crozet Islands in the SW Indian Ocean. The results of this programme, focussing on a quantitative estimate of carbon export per unit iron addition, will be presented.

Capital cost expenditure of high temperature latent and sensible thermal energy storage systems

NASA Astrophysics Data System (ADS)

Jacob, Rhys; Saman, Wasim; Bruno, Frank

2017-06-01

In the following study cost estimates have been undertaken for an encapsulated phase change material (EPCM) packed bed, a packed bed thermocline and a traditional two-tank molten salt system. The effect of various heat transfer fluids (air and molten salt), system configuration (cascade vs one PCM, and direct vs indirect) and temperature difference (ΔT = 100-500 °C) on the cost estimate of the system was also investigated. Lastly, the storage system boundary was expanded to include heat exchangers, pumps and fans, and heat tracing so that a thorough cost comparison could be undertaken. The results presented in this paper provide a methodology to quickly compare various systems and configurations while providing design limits for the studied technologies.

Millennial-scale variability in dust deposition, marine export production, and nutrient consumption in the glacial subantarctic ocean (Invited)

NASA Astrophysics Data System (ADS)

Martinez-Garcia, A.; Sigman, D. M.; Anderson, R. F.; Ren, H. A.; Hodell, D. A.; Straub, M.; Jaccard, S.; Eglinton, T. I.; Haug, G. H.

2013-12-01

Based on the limitation of modern Southern Ocean phytoplankton by iron and the evidence of higher iron-bearing dust fluxes to the ocean during ice ages, it has been proposed that iron fertilization of Southern Ocean phytoplankton contributed to the reduction in atmospheric CO2 during ice ages. In the Subantarctic zone of the Atlantic Southern Ocean, glacial increases in dust flux and export production have been documented, supporting the iron fertilization hypothesis. However, these observations could be interpreted alternatively as resulting from the equatorward migration of Southern Ocean fronts during ice ages if the observed productivity rise was not accompanied by an increase in major nutrient consumption. Here, new 230Th-normalized lithogenic and opal fluxes are combined with high-resolution biomarker measurements to reconstruct millennial-scale changes in dust deposition and marine export production in the subantarctic Atlantic over the last glacial cycle. In the same record foraminifera-bound nitrogen isotopes are used to reconstruct ice age changes in surface nitrate utilization, providing a comprehensive test of the iron fertilization hypothesis. Elevation in foraminifera-bound δ15N, indicating more complete nitrate consumption, coincides with times of surface cooling and greater dust flux and export production. These observations indicate that the ice age Subantarctic was characterized by iron fertilized phytoplankton growth. The resulting strengthening of the Southern Ocean's biological pump can explain the ~40 ppm lowering of CO2 that characterizes the transitions from mid-climate states to full ice age conditions as well as the millennial-scale atmospheric CO2 fluctuations observed within the last ice age

Polyamines cause plasma membrane depolarization, activate Ca2+-, and modulate H+-ATPase pump activity in pea roots.

PubMed

Pottosin, Igor; Velarde-Buendía, Ana María; Bose, Jayakumar; Fuglsang, Anja T; Shabala, Sergey

2014-06-01

Polyamines regulate a variety of cation and K(+) channels, but their potential effects on cation-transporting ATPases are underexplored. In this work, noninvasive microelectrode ion flux estimation and conventional microelectrode techniques were applied to study the effects of polyamines on Ca(2+) and H(+) transport and membrane potential in pea roots. Externally applied spermine or putrescine (1mM) equally activated eosin yellow (EY)-sensitive Ca(2+) pumping across the root epidermis and caused net H(+) influx or efflux. Proton influx induced by spermine was suppressed by EY, supporting the mechanism in which Ca(2+) pump imports 2 H(+) per each exported Ca(2+). Suppression of the Ca(2+) pump by EY diminished putrescine-induced net H(+) efflux instead of increasing it. Thus, activities of Ca(2+) and H(+) pumps were coupled, likely due to the H(+)-pump inhibition by intracellular Ca(2+). Additionally, spermine but not putrescine caused a direct inhibition of H(+) pumping in isolated plasma membrane vesicles. Spermine, spermidine, and putrescine (1mM) induced membrane depolarization by 70, 50, and 35 mV, respectively. Spermine-induced depolarization was abolished by cation transport blocker Gd(3+), was insensitive to anion channels' blocker niflumate, and was dependent on external Ca(2+). Further analysis showed that uptake of polyamines but not polyamine-induced cationic (K(+)+Ca(2+)+H(+)) fluxes were a main cause of membrane depolarization. Polyamine increase is a common component of plant stress responses. Activation of Ca(2+) efflux by polyamines and contrasting effects of polyamines on net H(+) fluxes and membrane potential can contribute to Ca(2+) signalling and modulate a variety of transport processes across the plasma membrane under stress. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Tank 26 Evaporator Feed Pump Transfer Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamburello, David; Dimenna, Richard; Lee, Si

2009-02-11

The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics methods to determine the amount of entrained sludge solids pumped out of the tank to the evaporator with the downcomer turned on. The analysis results showed that, for the maximummore » and minimum supernate levels in Tank 26 (252.5 and 72 inches above the sludge layer, respectively), the evaporator feed pump will entrain between 0.03 and 0.1 wt% sludge undissolved solids weight fraction into the eductor, respectively, and therefore are an order of magnitude less than the 1.0 wt% undissolved solids loading criteria to feed the evaporator. Lower tank liquid levels, with respect to the sludge layer, result in higher amounts of sludge entrainment due to the increased velocity of the plunging jets from the downcomer and evaporator feed pump bypass as well as decreased dissipation depth. Revision 1 clarifies the analysis presented in Revision 0 and corrects a mathematical error in the calculations for Table 4.1 in Revision 0. However, the conclusions and recommendations of the analysis do not change for Revision 1.« less

Concentrated solar power on demand demonstration: Construction and operation of a 25 kW prototype

NASA Astrophysics Data System (ADS)

Gil, Antoni; Codd, Daniel S.; Zhou, Lei; Trumper, David; Calvet, Nicolas; Slocum, Alexander H.

2016-05-01

Currently, the majority of concentrated solar power (CSP) plants built worldwide integrate thermal energy storage (TES) systems which enable dispatchable output and higher global plant efficiencies. TES systems are typically based on two tank molten salt technology which involves inherent drawbacks such as parasitic pumping losses and electric tracing of pipes, risk of solidification and high capital costs. The concept presented in this paper is based on a single tank where the concentrated sunlight is directly focused on the molten salt. Hot and cold volumes of salt (at 565 °C and 280 °C, respectively) are axially separated by an insulated divider plate which helps maintain the thermal gradient. The concept, based on existing technologies, seeks to avoid the listed drawbacks as well as reducing the final cost of the TES system. In order to demonstrate its feasibility, Masdar Institute (MI) and Massachusetts Institute of Technology are developing a 25 kW prototype to be tested in the Masdar Solar Platform beam down facility.

The Importance of Subsurface Production for Carbon Export - Evidence from Past Oceans

NASA Astrophysics Data System (ADS)

Kemp, A. E. S.

2016-02-01

The maxim of the geological concept of uniformitarianism is "the present is the key to the past", but in the context of our temporally and spatially minimal observational record of modern ocean biogeochemical processes, ancient ocean sediments may provide critical evidence of the key species involved in carbon flux. Specifically, laminated marine sediments that preserve the seasonal flux cycle represent "palaeo-sediment traps" that vastly expand our knowledge of the operations of the marine biological carbon pump. Several key subsurface-dwelling diatom taxa, hitherto thought to be biogeochemically insignificant, are dominant components of ancient marine sediments. For example, the sapropels and equivalent horizons that have accumulated in the Mediterranean over the past 5 million years, contain abundant rhizosolenid and hemiaulid diatoms. These deposits contain the highest concentrations of organic carbon and there is extensive evidence that this was produced by subsurface production in a deep chlorophyll maximum. The highly stratified conditions that led to this subsurface production and carbon flux are in contrast to prevailing views that have held upwelling systems as those with the highest potential for export in the global ocean. Similarly, studies of ancient "greenhouse" periods such as the Cretaceous, with highly stratified oceans and which are potential analogues for future climate change, show evidence for extensive subsurface production. Together with emerging evidence from stratified regions of the modern ocean, such as the subtropical gyres, insights from these ancient oceans suggest that a reappraisal is required of current views on key phytoplankton producers and their role the operation of the marine biological carbon pump.

Adaptation of H+-pumping and plasma membrane H+ ATPase activity in proteoid roots of white lupin under phosphate deficiency.

PubMed

Yan, Feng; Zhu, Yiyong; Müller, Caroline; Zörb, Christian; Schubert, Sven

2002-05-01

White lupin (Lupinus albus) is able to adapt to phosphorus deficiency by producing proteoid roots that release a huge amount of organic acids, resulting in mobilization of sparingly soluble soil phosphate in rhizosphere. The mechanisms responsible for the release of organic acids by proteoid root cells, especially the trans-membrane transport processes, have not been elucidated. Because of high cytosolic pH, the release of undissociated organic acids is not probable. In the present study, we focused on H+ export by plasma membrane H+ ATPase in active proteoid roots. In vivo, rhizosphere acidification of active proteoid roots was vanadate sensitive. Plasma membranes were isolated from proteoid roots and lateral roots from P-deficient and -sufficient plants. In vitro, in comparison with two types of lateral roots and proteoid roots of P-sufficient plants, the following increase of the various parameters was induced in active proteoid roots of P-deficient plants: (a) hydrolytic ATPase activity, (b) Vmax and Km, (c) H+ ATPase enzyme concentration of plasma membrane, (d) H+-pumping activity, (e) pH gradient across the membrane of plasmalemma vesicles, and (f) passive H+ permeability of plasma membrane. In addition, lower vanadate sensitivity and more acidic pH optimum were determined for plasma membrane ATPase of active proteoid roots. Our data support the hypothesis that in active proteoid root cells, H+ and organic anions are exported separately, and that modification of plasma membrane H+ ATPase is essential for enhanced rhizosphere acidification by active proteoid roots.

Modification of plasma membrane proton pumps in cucumber roots as an adaptation mechanism to salt stress.

PubMed

Janicka-Russak, Małgorzata; Kabała, Katarzyna; Wdowikowska, Anna; Kłobus, Grażyna

2013-07-01

The effect of salt stress (50mM NaCl) on modification of plasma membrane (PM) H(+)-ATPase (EC 3.6.3.14) activity in cucumber roots was studied. Plants were grown under salt stress for 1, 3 or 6 days. In salt-stressed plants, weak stimulation of ATP hydrolytic activity of PM H(+)-ATPase and significant stimulation of proton transport through the plasma membrane were observed. The H(+)/ATP coupling ratio in the plasma membrane of plants subjected to salt stress significantly increased. The greatest stimulation of PM H(+)-ATPase was in 6-day stressed plants. Increased H2O2 accumulation under salt stress conditions in cucumber roots was also observed, with the greatest accumulation observed in 6-day stressed plants. Additionally, during the sixth day of salinity, there appeared heat shock proteins (HSPs) 17.7 and 101, suggesting that repair processes and adaptation to stress occurred in plants. Under salt stress conditions, fast post-translational modifications took place. Protein blot analysis with antibody against phosphothreonine and 14-3-3 proteins showed that, under salinity, the level of those elements increased. Additionally, under salt stress, activity changes of PM H(+)-ATPase can partly result from changes in the pattern of expression of PM H(+)-ATPase genes. In cucumber seedlings, there was increased expression of CsHA10 under salt stress and the transcript of a new PM H(+)-ATPase gene isoform, CsHA1, also appeared. Accumulation of the CsHA1 transcript was induced by NaCl exposure, and was not expressed at detectable levels in roots of control plants. The appearance of a new PM H(+)-ATPase transcript, in addition to the increase in enzyme activity, indicates the important role of the enzyme in maintaining ion homeostasis in plants under salt stress. Copyright © 2013 Elsevier GmbH. All rights reserved.

Bathymetric map of the north part of Great Salt Lake, Utah, 2006

USGS Publications Warehouse

Baskin, Robert L.; Turner, Jane

2006-01-01

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands, collected bathymetric data for the north part of Great Salt Lake during the spring and early summer of 2006 using a single beam, high-definition fathometer and real-time differential global positioning system. Approximately 5.2 million depth readings were collected along more than 765 miles of survey transects for construction of this map. Sound velocities were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed using commercial hydrographic software and exported into a geographic information system (GIS) software for mapping. Due to the shallow nature of the lake and the limitations of the instrumentation, contours above an altitude of 4,194 feet were digitized from existing USGS 1:24,000 source-scale digital line graph data. The Behrens Trench is approximately located.For additional information on methods used to derive the bathymetric contours for this map, please see Baskin, Robert L., 2006, Calculation of area and volume for the North Part of Great Salt Lake, Utah, U.S. Geological Survey Open-File Report OFR–2006–1359

Means and method of sampling flow related variables from a waterway in an accurate manner using a programmable calculator

Treesearch

Rand E. Eads; Mark R. Boolootian; Steven C. [Inventors] Hankin

1987-01-01

Abstract - A programmable calculator is connected to a pumping sampler by an interface circuit board. The calculator has a sediment sampling program stored therein and includes a timer to periodically wake up the calculator. Sediment collection is controlled by a Selection At List Time (SALT) scheme in which the probability of taking a sample is proportional to its...

View forward in starboard engine room, compartment C1. Lagged cylinders ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View forward in starboard engine room, compartment C-1. Lagged cylinders at lower right are part of a steam engine that poers the salt water circulating pumps. Note main throttle wheel at lower center of photograph. Handles at lower center are cylinder manifold drains. Handles to the right are engine starting valves. (062) - USS Olympia, Penn's Landing, 211 South Columbus Boulevard, Philadelphia, Philadelphia County, PA

The Slow Moving Threat of Groundwater Salinization: Mechanisms, Costs, and Adaptation Strategies

NASA Astrophysics Data System (ADS)

Pauloo, R.; Guo, Z.; Fogg, G. E.

2016-12-01

Population growth, the Green Revolution, and climate uncertainties have accelerated overdraft in groundwater basins worldwide, which in some regions is converting these basins into closed hydrologic systems, where the dominant exits for water are evapotranspiration and pumping. Irrigated agricultural basins are particularly at risk to groundwater salinization, as naturally occurring (i.e., sodium, potassium, chloride) and anthropogenic (i.e., nitrate fertilizers) salts leach back into the water table through the root zone, while a large portion of pumped groundwater leaves the system as it is evapotranspired by crops. Decreasing water quality associated with increases in Total Dissolved Solids (TDS) has been documented in aquifers across the United States in the past half century. This study suggests that the increase in TDS in aquifers can be partially explained by closed basin hydrogeology and rock-water interactions leading to groundwater salinization. This study will present: (1) a report on historical water quality in the Tulare basin, (2) a forward simulation of salt balance in Tulare Basin based on the Department of Water Resources numerical model C2VSim, and a simple mixing model, (3) an economic analysis forecasting the cost of desalination under varying degrees of managed groundwater recharge where the basin is gradually filled, avoiding hydraulic closure.

Helicobacter pylori eradication therapy: A review of current trends.

PubMed

Olokoba, A B; Obateru, O A; Bojuwoye, M O

2013-01-01

Helicobacter pylori has been implicated in the formation of chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue lymphoma and gastric cancer. Eradication of H. Pylori has been recommended as treatment and prevention for these complications. This review is based on a search of Medline, the Cochrane Database of Systemic Reviews, and citation lists of relevant publications. Subject heading and key words used include H. Pylori, current treatment and emerging therapy. Only articles in English were included. There has been a substantial decline in the H. pylori eradication rates over the years, despite the use of proton pump inhibitor and bismuth salts for triple and quadruple therapies respectively. The reasons for eradication failure are diverse, among them, antibiotic resistance is an important factor in the treatment failure. Primary resistance to clarithromycin or metronidazole significantly affects the efficacy of eradication therapy. This has led to the introduction of second line, third line "rescue," and sequential therapies for resistant cases. Subsequently, new antibiotic combinations with proton-pump inhibitors and bismuth salts are being studied in the last decade, to find out the antibiotics that are capable of increasing the eradication rates. Some of these antibiotics include Levofloxacin, Doxycycline, Rifaximin, Rifampicin, Furazolidone based therapies. Studies are ongoing to determine the efficacy of Lactoferrin based therapy.

Summary of hydrologic data collected during 1976 in Dade County, Florida

USGS Publications Warehouse

Hull, John E.

1978-01-01

During 1976 rainfall was 1.58 inches below the long-term average. Ground-water levels ranged from 0.4 foot above to 0.5 foot below average. The highest and lowest ground water for the year were both 1 foot below their long-term averages. In the Hialeah-Miami Springs area, water levels in wells near the centers of the heaviest pumping ranged from 8.0 to 9.5 feet below msl (mean sea level, 1929); and in the southwest well-field area, ground-water levels near the centers of pumping ranged from 2.0 feet above to 3.0 feet below msl. The combined average daily discharge from nine major streams and canals that flow eastward into tidal waters was 1,666 cubic feet per second (cfs), 609 cfs above the combined average daily flow for the 1975 water year. The combined average daily flow through the Tamiami Canal outlets was 783 cfs, 215 cfs above that of the 1975 water year. The 1976 position of the salt fron in the coastal part of the Biscayne aquifer was about the same as in 1975 except in the vicinity of Mowry Canal south of Homestead Air Force Base where the salt front had encroached farther inland. (Woodard-USGS)

Summary of hydrologic data collected during 1977 in Dade County, Florida

USGS Publications Warehouse

Hull, John E.

1979-01-01

During 1977 rainfall was 1.52 inches above the long-term average in Dade County, Fla. Ground-water levels ranged from 0.3 foot above to 0.1 foot below average. The highest and lowest ground-water levels for the year were 1 foot below and 1 foot above their long-term average. In the Hialeah-Miami Springs area , water levels in wells near the centers of the heaviest pumping ranged from 7.2 to 11.9 feet below mean sea level, 1929; and in the Southwest well-field area, ground-water levels near the centers of pumping ranged from 1.0 foot above to 1.5 feet below mean sea level. In 1977 the combined average daily discharge from nine major streams and canals that flow eastward into tidal waters was 1,712 cubic feet per second (cfs), 46 cfs above the combined average daily flow for 1976. The combined average daily flow through the Tamiami Canal outlets was 582 cfs, 201 cfs above that of 1976. The 1977 position of the salt front in the coastal part of the Biscayne aquifer was about the same as in 1976, except south of Homestead Air Force Base where the salt front had encroached farther inland. (Woodard-USGS)

Summary of hydrologic data collected during 1975 in Dade County, Florida

USGS Publications Warehouse

Hull, John E.; Beaven, T.R.

1977-01-01

During the 1975 calendar year rainfall in Dade County, Fla., was 14.89 inches below the long-term average (57.17 in.). Ground-water levels ranged from 0.1 foot above to 1.1 feet below average. The highest and lowest ground-water levels for the year were both 1 foot below their long-term averages. In the Hialeah-Miami Springs area, ground-water levels in wells near the centers of the heaviest pumping ranged from 9.8 to 11.2 feet below mean sea level and in the Southwest well field area, ground-water levels near the centers of pumping ranged from 3.5 feet above to 3.4 feet below mean sea level. The combined average daily discharge from eight major streams and canals that flow into Biscayne Bay was 1,014 cubic feet per second (cfs), 124 cfs above the combined average daily flow for the 1974 water year. The combined average daily flow through the Tamiami Canal outlets was 568 cfs, 202 cfs below that of the 1974 water year. The position of the salt front in 1975 in the coastal part of the Biscayne aquifer was about the same as in 1974 except at Miami International Airport and Homestead Air Force Base where the salt front had encroached farther inland. (Woodard-USGS)

CSPonD demonstrative project: Start-up process of a 25 kW prototype

NASA Astrophysics Data System (ADS)

Gil, Antoni; Grange, Benjamin; Perez, Victor G.; Tetreault-Friend, Melanie; Codd, Daniel S.; Calvet, Nicolas; Slocum, Alexander S.

2017-06-01

The current concept of commercial concentrated solar power (CSP) plants, based on the concept of a solar field, receiver, storage and power block, experienced significant growth in the past decades. The power block is the most well know part of the plant, while solar field depends on the receiver technology. The dominant receiver technologies are parabolic troughs and central towers. Most thermal energy storage (TES) relies on two tanks of molten salts, one hot and one cold serviced by pumps and piping systems. In spite of the technical development level achieved by these systems, efficiency is limited, mainly caused by thermal losses in piping, parasitic losses due to electric tracing and pumping and receiver limitations. In order to mitigate the these issues, a new concept called Concentrated Solar Power on Demand (CSPonD), was developed, consisting of a direct absorption Solar Salt CSP receiver which simultaneously acts as TES tank. Currently, in the frame of the flagship collaborative project between the Masdar Institute (UAE) and the Massachusetts Institute of Technology (USA) a 25 kW demonstrative prototype is in its final building phase at the Masdar Institute Solar Platform. The present paper, explains the demonstration prototype based on the CSPonD concept, with emphasis on the planned start-up process for the facility.

Marine phytoplankton stoichiometry mediates nonlinear interactions between nutrient supply, temperature, and atmospheric CO2

NASA Astrophysics Data System (ADS)

Moreno, Allison R.; Hagstrom, George I.; Primeau, Francois W.; Levin, Simon A.; Martiny, Adam C.

2018-05-01

Marine phytoplankton stoichiometry links nutrient supply to marine carbon export. Deviations of phytoplankton stoichiometry from Redfield proportions (106C : 1P) could therefore have a significant impact on carbon cycling, and understanding which environmental factors drive these deviations may reveal new mechanisms regulating the carbon cycle. To explore the links between environmental conditions, stoichiometry, and carbon cycling, we compared four different models of phytoplankton C : P: a fixed Redfield model, a model with C : P given as a function of surface phosphorus concentration (P), a model with C P given as a function of temperature, and a new multi-environmental model that predicts C : P as a function of light, temperature, and P. These stoichiometric models were embedded into a five-box ocean circulation model, which resolves the three major ocean biomes (high-latitude, subtropical gyres, and tropical upwelling regions). Contrary to the expectation of a monotonic relationship between surface nutrient drawdown and carbon export, we found that lateral nutrient transport from lower C : P tropical waters to high C : P subtropical waters could cause carbon export to decrease with increased tropical nutrient utilization. It has been hypothesized that a positive feedback between temperature and pCO2, atm will play an important role in anthropogenic climate change, with changes in the biological pump playing at most a secondary role. Here we show that environmentally driven shifts in stoichiometry make the biological pump more influential, and may reverse the expected positive relationship between temperature and pCO2, atm. In the temperature-only model, changes in tropical temperature have more impact on the Δ pCO2, atm (˜ 41 ppm) compared to subtropical temperature changes (˜ 4.5 ppm). Our multi-environmental model predicted a decline in pCO2, atm of ˜ 46 ppm when temperature spanned a change of 10 °C. Thus, we find that variation in marine phytoplankton stoichiometry and its environmental controlling factors can lead to nonlinear controls on pCO2, atm, suggesting the need for further studies of ocean C : P and the impact on ocean carbon cycling.

Analog-model studies of ground-water hydrology in the Houston District, Texas

USGS Publications Warehouse

Jorgensen, Donald G.

1974-01-01

The major water-bearing units in the Houston district are the Chicot and the Evangeline aquifers. The Chicot aquifer overlies the Evangeline aquifer, which is underlain by the Burkeville confining layer. Both aquifers consist of unconsolidated and discontinuous layers of sand and clay that dip toward the Gulf of Mexico. Heavy pumping of fresh water has caused large declines in the altitudes of the potentiometric surfaces in both aquifers and has created large cones of depression around Houston. The declines have caused compaction of clay layers, which has resulted in land surface subsidence and the movement of saline ground water toward the centers of the cones of depression. An electric analog model was used to study the hydrologic system and to simulate the declines in the altitudes of the potentiometric surfaces for several alternative plans of ground-water development. The results indicate that the largest part. of the pumped water comes from storage in the water-table part of the Chicot aquifer. Vertical leakage from the aquifers and water derived from the compaction of clay layers in the aquifers are also large sources of the water being pumped. The response of the system, as observed on the model, indicates that development of additional ground-water supplies from the water-table part of the Chicot aquifer north of Houston would result in a minimum decline of the altitudes of the potentiometric surfaces. Total withdrawals of about 1,000 million gallons (5.8 million cubic meters) per day may be possible without seriously, increasing subsidence or salt-water encroachment. Analyses of the recovery of water levels indicate that both land-surface subsidence and salt-water encroachment could be reduced by artificially recharging the artesian part of the aquifer.

Oxygen-deficient metabolism and corneal edema

PubMed Central

Leung, B.K.; Bonanno, J.A.; Radke, C.J.

2014-01-01

Wear of low-oxygen-transmissible soft contact lenses swells the cornea significantly, even during open eye. Although oxygen-deficient corneal edema is well-documented, a self-consistent quantitative prediction based on the underlying metabolic reactions is not available. We present a biochemical description of the human cornea that quantifies hypoxic swelling through the coupled transport of water, salt, and respiratory metabolites. Aerobic and anaerobic consumption of glucose, as well as acidosis and pH buffering, are incorporated in a seven-layer corneal model (anterior chamber, endothelium, stroma, epithelium, postlens tear film, contact lens, and prelens tear film). Corneal swelling is predicted from coupled transport of water, dissolved salts, and especially metabolites, along with membrane-transport resistances at the endothelium and epithelium. At the endothelium, the Na+/K+ - ATPase electrogenic channel actively transports bicarbonate ion from the stroma into the anterior chamber. As captured by the Kedem–Katchalsky membrane-transport formalism, the active bicarbonate-ion flux provides the driving force for corneal fluid pump-out needed to match the leak-in tendency of the stroma. Increased lactate-ion production during hypoxia osmotically lowers the pump-out rate requiring the stroma to swell to higher water content. Concentration profiles are predicted for glucose, water, oxygen, carbon dioxide, and hydronium, lactate, bicarbonate, sodium, and chloride ions, along with electrostatic potential and pressure profiles. Although the active bicarbonate-ion pump at the endothelium drives bicarbonate into the aqueous humor, we find a net flux of bicarbonate ion into the cornea that safeguards against acidosis. For the first time, we predict corneal swelling upon soft-contact-lens wear from fundamental biophysico-chemical principles. We also successfully predict that hypertonic tear alleviates contact-lens-induced edema. PMID:21820076

Oxygen-deficient metabolism and corneal edema.

PubMed

Leung, B K; Bonanno, J A; Radke, C J

2011-11-01

Wear of low-oxygen-transmissible soft contact lenses swells the cornea significantly, even during open eye. Although oxygen-deficient corneal edema is well-documented, a self-consistent quantitative prediction based on the underlying metabolic reactions is not available. We present a biochemical description of the human cornea that quantifies hypoxic swelling through the coupled transport of water, salt, and respiratory metabolites. Aerobic and anaerobic consumption of glucose, as well as acidosis and pH buffering, are incorporated in a seven-layer corneal model (anterior chamber, endothelium, stroma, epithelium, postlens tear film, contact lens, and prelens tear film). Corneal swelling is predicted from coupled transport of water, dissolved salts, and especially metabolites, along with membrane-transport resistances at the endothelium and epithelium. At the endothelium, the Na+/K+ - ATPase electrogenic channel actively transports bicarbonate ion from the stroma into the anterior chamber. As captured by the Kedem-Katchalsky membrane-transport formalism, the active bicarbonate-ion flux provides the driving force for corneal fluid pump-out needed to match the leak-in tendency of the stroma. Increased lactate-ion production during hypoxia osmotically lowers the pump-out rate requiring the stroma to swell to higher water content. Concentration profiles are predicted for glucose, water, oxygen, carbon dioxide, and hydronium, lactate, bicarbonate, sodium, and chloride ions, along with electrostatic potential and pressure profiles. Although the active bicarbonate-ion pump at the endothelium drives bicarbonate into the aqueous humor, we find a net flux of bicarbonate ion into the cornea that safeguards against acidosis. For the first time, we predict corneal swelling upon soft-contact-lens wear from fundamental biophysico-chemical principles. We also successfully predict that hypertonic tear alleviates contact-lens-induced edema. Copyright © 2011 Elsevier Ltd. All rights reserved.

Influence of particulates on phosphorus loading exported from farm drainage during a storm event in the Everglades Agricultural Area

NASA Astrophysics Data System (ADS)

Bhadha, J. H.; Lang, T. A.; Daroub, S. H.

2015-12-01

The purpose of this study was to evaluate the influence of particulates on P loading captured during a single storm event. The Everglades Agricultural Area of Florida comprises 280,000 hectares of organic soil farmland artificially drained by ditches, canals and pumps. Phosphorus (P)-enriched suspended particulates in canals are susceptible to transport and can contribute significantly to the overall P loads in drainage water. A settling tank experiment was conducted to capture particulates during tropical storm Isaac in 2012 from three farms approximately 2.4 to 3.6 km2 in size. Farm canal discharge water was collected in a series of two 200 liter settling tanks over a seven-day drainage period, during tropical storm Isaac. Water from the settling tanks was siphoned through Imhoff settling cones, where the particulates were allowed to settle and collected for P-fractionation analyses, and compared to intact sediment cores collected from the bottom of the canals. The discharged particulates contained higher organic matter content (OM), total P, and labile P fractions compared to the canal bottom sediments. Based on the equilibrium P concentrations, surface sediments behave as a source of P to the water column. A seven-day continuous drainage event exported 4.7 to 11.1 metric tons of suspended solids per farm, corresponding to 32 to 63 kg of particulate P being lost to downstream ecosystems. Drainage associated to a single seven-day storm event exported up to 61% of the total annual farm P load. It is evident from this study that short-term, high-intensity storm events can skew annual P loads due to the export of significantly higher particulate matter from farm canals. Exported particulates rich in P can provide a supplemental source of nutrients if captured and replenished back into the farmlands, as a sustainable farming practice.

Studies on H-Translocating ATPases in Plants of Varying Resistance to Salinity : I. Salinity during Growth Modulates the Proton Pump in the Halophyte Atriplex nummularia.

PubMed

Braun, Y; Hassidim, M; Lerner, H R; Reinhold, L

1986-08-01

Membrane vesicles were isolated from the roots of the halophyte Atriplex nummularia Lindl. H(+)-translocating Mg(2+)-ATPase activity was manifested by the establishment of a positive membrane potential (measured as SCN(-) accumulation); and also by the establishment of a transmembrane pH gradient (measured by quinacrine fluorescence quenching). H(+)-translocation was highly specific to ATP and was stable to oligomycin. Growing the plants in the presence of 400 millimolar NaCl doubled the proton-translocating activity per milligram of membrane protein and otherwise modulated it in the following ways. First, the flat pH profile observed in non-salt-grown plants was transformed to one showing a peak at about pH 6.2. Second, the lag effect observed at low ATP concentration in curves relating SCN(-) accumulation to ATP concentration was abolished; the concave curvature shown in the double reciprocal plot was diminished. Third, sensitivity to K-2 (N-morpholino)ethanesulfonic acid stimulation was shown in salt-grown plants (about 40% stimulation) but was absent in non-salt-grown plants. Fourth, the KCl concentration bringing about 50% dissipation of ATP-dependent SCN(-) accumulation was 20 millimolar for salt-grown plants and 50 millimolar for non-salt-grown plants. Vanadate sensitivity was shown in both cases. No clear NO(3) (-) inhibition was observed.

A Preliminary Appraisal of the Effect of Pumping on Seawater Intrusion and Upconing in a Small Tropical Island Using 2D Resistivity Technique

PubMed Central

Ramli, Mohammad Firuz; Ibrahim, Shaharin; Sulaiman, Wan Nor Azmin; Aris, Ahmad Zaharin

2014-01-01

The existing knowledge regarding seawater intrusion and particularly upconing, in which both problems are linked to pumping, entirely relies on theoretical assumptions. Therefore, in this paper, an attempt is made to capture the effects of pumping on seawater intrusion and upconing using 2D resistivity measurement. For this work, two positions, one perpendicular and the other parallel to the sea, were chosen as profile line for resistivity measurement in the coastal area near the pumping wells of Kapas Island, Malaysia. Subsequently, water was pumped out of two pumping wells simultaneously for about five straight hours. Then, immediately after the pumping stopped, resistivity measurements were taken along the two stationed profile lines. This was followed by additional measurements after four and eight hours. The results showed an upconing with low resistivity of about 1–10 Ωm just beneath the pumping well along the first profile line that was taken just after the pumping stopped. The resistivity image also shows an intrusion of saline water (water enriched with diluted salt) from the sea coming towards the pumping well with resistivity values ranging between 10 and 25 Ωm. The subsequent measurements show the recovery of freshwater in the aquifer and how the saline water is gradually diluted or pushed out of the aquifer. Similarly the line parallel to the sea (L2) reveals almost the same result as the first line. However, in the second and third measurements, there were some significant variations which were contrary to the expectation that the freshwater may completely flush out the saline water from the aquifer. These two time series lines show that as the areas with the lowest resistivity (1 Ωm) shrink with time, the low resistivity (10 Ωm) tends to take over almost the entire area implying that the freshwater-saltwater equilibrium zone has already been altered. These results have clearly enhanced our current understanding and add more scientific weight to the theoretical assumptions on the effects of pumping on seawater intrusion and upconing. PMID:25574493

Carbon Transformations and Source - Sink Dynamics along a River, Marsh, Estuary, Ocean Continuum

NASA Astrophysics Data System (ADS)

Anderson, I. C.; Crosswell, J.; Czapla, K.; Van Dam, B.

2017-12-01

Estuaries, the transition zone between land and the coastal ocean, are highly dynamic systems in which carbon sourced from watersheds, marshes, atmosphere, and ocean may be transformed, sequestered, or exported. The net fate of carbon in estuaries, governed by the interactions of biotic and physical drivers varying on spatial and temporal scales, is currently uncertain because of limited observational data. In this study, conducted in a temperate, microtidal, and shallow North Carolina USA estuary, carbon exchanges via river, tributary, and fringing salt marsh, air-water fluxes, sediment C accumulation, and metabolism were monitored over two-years, with sharply different amounts of rainfall. Air-water CO2 fluxes and metabolic variables were simultaneously measured in channel and shoal by conducting high-resolution surveys at dawn, dusk and the following dawn. Marsh CO2 exchanges, sediment C inputs, and lateral exports of DIC and DOC were also measured. Carbon flows between estuary regions and export to the coastal ocean were calculated by quantifying residual transport of DIC and TOC down-estuary as flows were modified by sources, sinks and internal transformations. Variation in metabolic rates, CO2, TOC and DIC exchanges were large when determined for short time and limited spatial scales. However, when scaled to annual and whole estuarine scales, variation tended to decrease because of counteracting metabolic rates and fluxes between channel and shoal or between seasons. Although overall salt marshes accumulated OC, they were a negligible source of DIC and DOC to the estuary, and net inputs of C to the marsh were mainly derived from sediment OC. These results, as observed in other observational studies of estuaries, show that riverine input, light, temperature and metabolism are major controls on carbon cycling. Comparison of our results with other types of estuaries varying in depth, latitude, and nutrification demonstrates large discrepancies underscoring the limitations of current sampling designs, models and datasets in representing system-scale diversity; thus, a more practical approach may be to choose a small number of representative coastal systems, coordinate research efforts to quantify the relevant fluxes and constrain a range of environmental conditions that influence carbon cycling.

Effect of Yin-Zhi-Huang on up-regulation of Oatp2, Ntcp, and Mrp2 proteins in estrogen-induced rat cholestasis.

PubMed

Zhang, Guoqiang; Zhou, Yan; Rao, Zhi; Qin, Hongyan; Wei, Yuhui; Ren, Jiangxia; Zhou, Liting; Wu, Xin'an

2015-03-01

Yin-Zhi-Huang (YZH), a prescription of traditional Chinese medicine, is widely used to treat neonatal jaundice or cholestasis. This study investigates the regulatory effect of YZH on the localization and expression of organic anion transporting polypeptides 2 (Oatp2), Na(+)-taurocholate co-transporting polypeptide (Ntcp), multidrug-resistance-associated protein 2 (Mrp2), and bile salt export pump (Bsep) in estrogen-induced cholestasis rats. Cholestasis model rats were induced via subcutaneous injection of estradiol benzoate (EB, 5 mg/kg/d) for 5 d. Other EB-induced rats were treated with saline (2 ml) or YZH (1.5 g/kg, two times a day) for 7, 14, and 21 d. The biochemical and pathologic examinations were performed. Moreover, the localization and expression of Oatp2, Ntcp, Mrp2, and Bsep were determined by immunohistochemisty and Western blotting, respectively. YZH treatment could significantly decrease the serum total bile acids (TBA) (4.9 ± 0.6-2.8 ± 0.8) and direct bilirubin (DBIL) (2.6 ± 0.7-1.0 ± 0.1) levels, improve the histological disorganization, and, respectively, increase the expression of Oatp2 and Ntcp by 46% and 28% compared with saline-treated (p < 0.05) rats at 14 d. The expression of Mrp2 increased by 45% was observed in YZH treated compared with saline-treated (p < 0.05) rats at 7 d. However, there was a little change in the expression of Bsep (p > 0.05) after YZH treatment for 7, 14, and 21 d. In conclusion, the therapeutic effect of YZH to cholestasis could be attributed to the regulation of Oatp2, Ntcp, Mrp2, and Bsep.

ABC-transporters are localized in caveolin-1-positive and reggie-1-negative and reggie-2-negative microdomains of the canalicular membrane in rat hepatocytes.

PubMed

Ismair, Manfred G; Häusler, Stephanie; Stuermer, Claudia A; Guyot, Christelle; Meier, Peter J; Roth, Jürgen; Stieger, Bruno

2009-05-01

The canalicular plasma membrane is constantly exposed to bile acids acting as detergents. Bile acids are essential to mediate release of biliary lipids from the canalicular membrane. Membrane microdomains (previously called lipid rafts) are biochemically defined by their resistance to detergent solubilization at cold temperature. We aimed to investigate the canalicular plasma membrane for the presence of microdomains, which could protect this membrane against the detergent action of bile acids. Highly purified rat liver canalicular plasma membrane vesicles were extracted with 1% Triton X-100 or 1% Lubrol WX at 4 degrees C and subjected to flotation through sucrose step gradients. Both detergents yielded detergent-resistant membranes containing the microdomain markers alkaline phosphatase and sphingomyelin. However, cholesterol was resistant to Lubrol WX solubilization, whereas it was only marginally resistant to solubilization by Triton X-100. The microdomain marker caveolin-1 was localized to the canalicular plasma membrane domain and was resistant to Lubrol WX, but to a large extent solubilized by Triton X-100. The two additional microdomain markers, reggie-1 and reggie-2, were localized to the basolateral and canalicular plasma membrane and were partially resistant to Lubrol WX but resistant to Triton X-100. The canalicular transporters bile salt export pump, multidrug resistance protein 2, multidrug resistance-associated protein 2, and Abcg5 were largely resistant to Lubrol WX but were solubilized by Triton X-100. These results indicate the presence of two different types of microdomains in the canalicular plasma membrane: "Lubrol-microdomains" and "Triton-microdomains". "Lubrol-microdomains" contain the machinery for canalicular bile formation and may be the starting place for canalicular lipid secretion.

Interactions of bilastine, a new oral H₁ antihistamine, with human transporter systems.

PubMed

Lucero, Maria Luisa; Gonzalo, Ana; Ganza, Alvaro; Leal, Nerea; Soengas, Itziar; Ioja, Eniko; Gedey, Szilvia; Jahic, Mirza; Bednarczyk, Dallas

2012-06-01

Membrane transporters play a significant role in facilitating transmembrane drug movement. For new pharmacological agents, it is important to evaluate potential interactions (e.g., substrate specificity and/or inhibition) with human transporters that may affect their pharmacokinetics, efficacy, or toxicity. Bilastine is a new nonsedating H₁ antihistamine indicated for the treatment of allergic rhinoconjunctivitis and urticaria. The in vitro inhibitory effects of bilastine were assessed on 12 human transporters: four efflux [multidrug resistance protein 1 (MDR1) or P-glycoprotein, breast cancer resistance protein (BCRP), multidrug resistance associated protein 2 (MRP2), and bile salt export pump) and eight uptake transporters (sodium taurocholate cotransporting polypeptide, organic cation transporter (OCT)1, organic anion transporter (OAT)1, OAT3, OCT2, OATP2B1, OATP1B1, and OATP1B3). Only mild inhibition was found for MDR1-, OCT1-, and OATP2B1-mediated transport of probe substrates at the highest bilastine concentration assayed (300 μM; half-maximal inhibitory concentration: ≥300 μM). Bilastine transport by MDR1, BCRP, OAT1, OAT3, and OCT2 was also investigated in vitro. Only MDR1 active transport of bilastine was relevant, whereas it did not appear to be a substrate of OCT2, OAT1, or OAT3, nor was it transported substantially by BCRP. Drug-drug interactions resulting from bilastine inhibition of drug transporters that would be generally regarded as clinically relevant are unlikely. Additionally, bilastine did not appear to be a substrate of human BCRP, OAT1, OAT3, or OCT2 and thus is not a potential victim of inhibitors of these transporters. On the other hand, based on in vitro evaluation, clinically relevant interactions with MDR1 inhibitors are anticipated.

Expression and role of the genes involved in the transport of bile acids in the liver and kidneys in mice.

PubMed

Attakpa, Eugène S; Djibril, Naguibou M; Baba-Moussa, Farid; Yessoufou, Ganiou; Sezan, Alphonse

2013-01-01

Bile acids are synthesized in the liver from cholesterol. This study investigated the impact and expression of different carriers of bile acid in the liver and kidneys. Eight-week-old male mice were used, which were fed for 15 days and divided into two groups: 15 mice fed with standard diet (control group) and another 15 mice fed with a rich diet of 5% cholesterol (second group). Bile acid dosage was based on their oxidation by 7α hydroxyl-steroid dehydrogenize. The mRNA expression was quantitatively analyzed by the real time of polymerase chain reaction (RT-PCR), and the expression of the renal carrier bile acid protein was analyzed by Western blot. The expression of bile salt export pump involved in the uptake of bile acids in the basolateral membrane of hepatocytes revealed no differences between the two groups of mice. However, the expression of multidrug resistance-associated protein 2 was reduced in mice of the second group. Moreover, the expressions of organic anion transporting polypeptide 4, organic anion transporting polypeptide 1, and sodium taurocholate co-transporting polypeptide (Ntcp) involved in the uptake of bile acids in the apical pole of hepatocytes are suppressed in mice of the second group. The expression of multidrug resistance-associated protein 3 involved in the secretion of bile acids in the apical membrane of hepatocytes revealed no significant differences between the two groups. In mice of the second group, blood concentration of bile acids on the last day was increased. In those mice, the expression of intestinal bile acid transporter was reduced in the kidneys compared with the control mice.

Nuclear factor-E2-related factor 2 is a major determinant of bile acid homeostasis in the liver and intestine

PubMed Central

Weerachayaphorn, Jittima; Mennone, Albert; Soroka, Carol J.; Harry, Kathy; Hagey, Lee R.; Kensler, Thomas W.

2012-01-01

The transcription factor nuclear factor-E2-related factor 2 (Nrf2) is a key regulator for induction of hepatic detoxification and antioxidant mechanisms, as well as for certain hepatobiliary transporters. To examine the role of Nrf2 in bile acid homeostasis and cholestasis, we assessed the determinants of bile secretion and bile acid synthesis and transport before and after bile duct ligation (BDL) in Nrf2−/− mice. Our findings indicate reduced rates of biliary bile acid and GSH excretion, higher levels of intrahepatic bile acids, and decreased expression of regulators of bile acid synthesis, Cyp7a1 and Cyp8b1, in Nrf2−/− compared with wild-type control mice. The mRNA expression of the bile acid transporters bile salt export pump (Bsep) and organic solute transporter (Ostα) were increased in the face of impaired expression of the multidrug resistance-associated proteins Mrp3 and Mrp4. Deletion of Nrf2 also decreased ileal apical sodium-dependent bile acid transporter (Asbt) expression, leading to reduced bile acid reabsorption and increased loss of bile acid in feces. Finally, when cholestasis is induced by BDL, liver injury was not different from that in wild-type BDL mice. These Nrf2−/− mice also had increased pregnane X receptor (Pxr) and Cyp3a11 mRNA expression in association with enhanced hepatic bile acid hydroxylation. In conclusion, this study finds that Nrf2 plays a major role in the regulation of bile acid homeostasis in the liver and intestine. Deletion of Nrf2 results in a cholestatic phenotype but does not augment liver injury following BDL. PMID:22345550

Paeoniflorin ameliorates cholestasis via regulating hepatic transporters and suppressing inflammation in ANIT-fed rats.

PubMed

Zhao, Yanling; He, Xuan; Ma, Xiao; Wen, Jianxia; Li, Pengyan; Wang, Jiabo; Li, Ruisheng; Zhu, Yun; Wei, Shizhang; Li, Haotian; Zhou, Xuelin; Li, Kun; Liu, Honghong; Xiao, Xiaohe

2017-05-01

Paeoniflorin has shown the obvious effect on cholestasis according to our previous research. However, its mechanism has not been absolutely explored yet. This study aims at evaluating the potential effect of paeoniflorin on alpha-naphthylisothiocyanate (ANIT) -induced cholestasis by inhibiting nuclear factor kappa-B (NF-κB) and simultaneously regulating hepatocyte transporters. Cholestasis was induced by administration of ANIT. The effect of paeoniflorin on serum indices such as total bilirubin (TBIL), direct bilirubin (DBIL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), γ-glutamyltranspeptidase (γ-GT), total bile acid (TBA) and histopathology of liver were determined. Liver protein levels of NF-κB, interleukin 1β (IL-1β) and the hepatocyte transporters such as Na + /taurocholate cotransporting polypeptide (NTCP), bile salt export pump (BSEP), multidrug resistance-associated protein 2 (MRP2) and cholesterol 7α-hydroxylase (Cyp7a1) were investigated by western blotting. The results demonstrated that paeoniflorin could decrease serum ALT, AST, ALP, γ-GT, TBIL, DBIL and TBA in ANIT-treated rats. Histological examination revealed that rats treated with paeoniflorin represented fewer neutrophils infiltration, edema and necrosis in liver tissue compared with ANIT rats. Moreover, paeoniflorin significantly reduced the over expressions of NF-κB and IL-1β induced by ANIT in liver tissue. In addition, the relative protein expressions of NTCP, BSEP, MRP2 but not Cyp7a1 were also restored by paeoniflorin. The potential mechanism of paeoniflorin in alleviating ANIT-induced cholestasis seems to be related to reduce the over expressions of NF-κB and hepatocyte transporters such as NTCP, BSEP as well as MRP2. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Dietary fish oil regulates gene expression of cholesterol and bile acid transporters in mice.

PubMed

Kamisako, Toshinori; Tanaka, Yuji; Ikeda, Takanori; Yamamoto, Kazuo; Ogawa, Hiroshi

2012-03-01

  Fish oil rich in n-3 polyunsaturated fatty acids is known to affect hepatic lipid metabolism. Several studies have demonstrated that fish oil may affect the bile acid metabolism as well as lipid metabolism, whereas only scarce data are available. The aim of this study was to investigate the effect of fish oil on the gene expression of the transporters and enzymes related to bile acid as well as lipid metabolism in the liver and small intestine.   Seven-week old male C57BL/6 mice were fed diets enriched in 10% soybean oil or 10% fish oil for 4 weeks. After 4 weeks, blood, liver and small intestine were obtained.   Hepatic mRNA expression of lipids (Abcg5/8, multidrug resistance gene product 2) and bile acids transporters (bile salt export pump, multidrug resistance associated protein 2 and 3, organic solute transporter α) was induced in fish oil-fed mice. Hepatic Cyp8b1, Cyp27a1 and bile acid CoA : amino acid N-acyltransferase were increased in fish oil-fed mice compared with soybean-oil fed mice. Besides, intestinal cholesterol (Abcg5/8) and bile acid transporters (multidrug resistance associated protein 2 and organic solute transporter α) were induced in fish oil-fed mice.   Fish oil induced the expression of cholesterol and bile acid transporters not only in liver but in intestine. The upregulation of Abcg5/g8 by fish oil is caused by an increase in cellular 27-HOC through Cyp27a1 induction. The hepatic induction of bile acid synthesis through Cyp27a1 may upregulate expression of bile acid transporters in both organs. © 2012 The Japan Society of Hepatology.

Evaluation of the endothelin receptor antagonists ambrisentan, darusentan, bosentan, and sitaxsentan as substrates and inhibitors of hepatobiliary transporters in sandwich-cultured human hepatocytes.

PubMed

Hartman, J Craig; Brouwer, Kenneth; Mandagere, Arun; Melvin, Lawrence; Gorczynski, Richard

2010-06-01

To evaluate potential mechanisms of clinical hepatotoxicity, 4 endothelin receptor antagonists (ERAs) were examined for substrate activity and inhibition of hepatic uptake and efflux transporters in sandwich-cultured human hepatocytes. The 4 transporters studied were sodium-dependent taurocholate cotransporter (NTCP), organic anion transporter (OATP), bile salt export pump (BSEP), and multidrug resistance-associated protein 2 (MRP2). ERA transporter inhibition was examined using the substrates taurocholate (for NTCP and BSEP), [(3)H]estradiol-17beta-D-glucuronide (for OATP), and [2-D-penicillamine, 5-D-penicillamine]enkephalin (for MRP2). ERA substrate activity was evaluated using probe inhibitors ritonavir (OATP and BSEP), bromosulfalein (OATP), erythromycin (P-glycoprotein), probenecid (MRP2 and OATP), and cyclosporin (NTCP). ERAs were tested at 2, 20, and 100 micromol*L-1 for inhibition and at 2 micromol*L-1 as substrates. OATP, NTCP, or BSEP transport activity was not reduced by ambrisentan or darusentan. Bosentan and sitaxsentan attenuated NTCP transport at higher concentrations. Only sitaxsentan decreased OATP transport (52%), and only bosentan reduced BSEP transport (78%). MRP2 transport activity was unaltered. OATP inhibitors decreased influx of all ERAs. Darusentan influx was least affected (84%-100% of control), whereas bosentan was most affected (32%-58% of control). NTCP did not contribute to influx of ERAs. Only bosentan and darusentan were shown as substrates for both BSEP and P-glycoprotein efflux. All ERAs tested were substrates for at least one hepatic transporter. Bosentan and sitaxsentan, but not ambrisentan and darusentan, inhibited human hepatic transporters, which provides a potential mechanism for the increased hepatotoxicity observed for these agents in the clinical setting.

Transporter-Mediated Disposition, Clinical Pharmacokinetics and Cholestatic Potential of Glyburide and Its Primary Active Metabolites.

PubMed

Li, Rui; Bi, Yi-An; Vildhede, Anna; Scialis, Renato J; Mathialagan, Sumathy; Yang, Xin; Marroquin, Lisa D; Lin, Jian; Varma, Manthena V S

2017-07-01

Glyburide is widely used for the treatment of type 2 diabetes. We studied the mechanisms involved in the disposition of glyburide and its pharmacologically active hydroxy metabolites M1 and M2b and evaluated their clinical pharmacokinetics and the potential role in glyburide-induced cholestasis employing physiologically based pharmacokinetic (PBPK) modeling. Transport studies of parent and metabolites in human hepatocytes and transfected cell systems imply hepatic uptake mediated by organic anion-transporting polypeptides. Metabolites are also subjected to basolateral and biliary efflux by P-glycoprotein, breast cancer resistance protein, and multidrug resistance-associated proteins, and are substrates to renal organic anion transporter 3. A PBPK model in combination with a Bayesian approach was developed considering the identified disposition mechanisms. The model reasonably described plasma concentration time profiles and urinary recoveries of glyburide and the metabolites, implying the role of multiple transport processes in their pharmacokinetics. Predicted free liver concentrations of the parent (∼30-fold) and metabolites (∼4-fold) were higher than their free plasma concentrations. Finally, all three compounds showed bile salt export pump inhibition in vitro; however, significant in vivo inhibition was not apparent for any compound on the basis of a predicted unbound liver exposure-response effect model using measured in vitro IC 50 values. In conclusion, this study demonstrates the important role of multiple drug transporters in the disposition of glyburide and its active metabolites, suggesting that variability in the function of these processes may lead to pharmacokinetic variability in the parent and the metabolites, potentially translating to pharmacodynamic variability. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Direct methylation of FXR by Set7/9, a lysine methyltransferase, regulates the expression of FXR target genes

PubMed Central

Balasubramaniyan, Natarajan; Ananthanarayanan, Meena

2012-01-01

The farnesoid X receptor (FXR) is a ligand (bile acid)-dependent nuclear receptor that regulates target genes involved in every aspect of bile acid homeostasis. Upon binding of ligand, FXR recruits an array of coactivators and associated proteins, some of which have intrinsic enzymatic activity that modify histones or even components of the transcriptional complex. In this study, we show chromatin occupancy by the Set7/9 methyltransferase at the FXR response element (FXRE) and direct methylation of FXR in vivo and in vitro at lysine 206. siRNA depletion of Set7/9 in the Huh-7 liver cell line decreased endogenous mRNAs of the FXR target genes, the short heterodimer partner (SHP) and bile salt export pump (BSEP). Mutation of the methylation site at K206 of FXR to an arginine prevented methylation by Set7/9. A pan-methyllysine antibody recognized the wild-type FXR but not the K206R mutant form. An electromobility shift assay showed that methylation by Set7/9 enhanced binding of FXR/retinoic X receptor-α to the FXRE. Interaction between hinge domain of FXR (containing K206) and Set7/9 was confirmed by coimmunoprecipitation, GST pull down, and mammalian two-hybrid experiments. Set7/9 overexpression in Huh-7 cells significantly enhanced transactivation of the SHP and BSEP promoters in a ligand-dependent fashion by wild-type FXR but not the K206R mutant FXR. A Set7/9 mutant deficient in methyltransferase activity was also not effective in increasing transactivation of the BSEP promoter. These studies demonstrate that posttranslational methylation of FXR by Set7/9 contributes to the transcriptional activation of FXR-target genes. PMID:22345554

Nutrient availability and the ultimate control of the biological carbon pump in the western tropical South Pacific Ocean

NASA Astrophysics Data System (ADS)

Moutin, Thierry; Wagener, Thibaut; Caffin, Mathieu; Fumenia, Alain; Gimenez, Audrey; Baklouti, Melika; Bouruet-Aubertot, Pascale; Pujo-Pay, Mireille; Leblanc, Karine; Lefevre, Dominique; Helias Nunige, Sandra; Leblond, Nathalie; Grosso, Olivier; de Verneil, Alain

2018-05-01

Surface waters (0-200 m) of the western tropical South Pacific (WTSP) were sampled along a longitudinal 4000 km transect (OUTPACE cruise, DOI: 10.17600/15000900) during the austral summer (stratified) period (18 February to 3 April 2015) between the Melanesian Archipelago (MA) and the western part of the SP gyre (WGY). Two distinct areas were considered for the MA, the western MA (WMA), and the eastern MA (EMA). The main carbon (C), nitrogen (N), and phosphorus (P) pools and fluxes provide a basis for the characterization of the expected trend from oligotrophy to ultra-oligotrophy, and the building of first-order budgets at the daily and seasonal timescales (using climatology). Sea surface chlorophyll a well reflected the expected oligotrophic gradient with higher values obtained at WMA, lower values at WGY, and intermediate values at EMA. As expected, the euphotic zone depth, the deep chlorophyll maximum, and nitracline depth deepen from west to east. Nevertheless, phosphaclines and nitraclines did not match. The decoupling between phosphacline and nitracline depths in the MA allows for excess P to be locally provided in the upper water by winter mixing. We found a significant biological soft tissue carbon pump in the MA sustained almost exclusively by dinitrogen (N2) fixation and essentially controlled by phosphate availability in this iron-rich environment. The MA appears to be a net sink for atmospheric CO2, while the WGY is in quasi-steady state. We suggest that the necessary excess P, allowing the success of nitrogen fixers and subsequent carbon production and export, is mainly brought to the upper surface by local deep winter convection at an annual timescale rather than by surface circulation. While the origin of the decoupling between phosphacline and nitracline remains uncertain, the direct link between local P upper water enrichment, N2 fixation, and organic carbon production and export, offers a possible shorter timescale than previously thought between N input by N2 fixation and carbon export. The low iron availability in the SP gyre and P availability in the MA during the stratified period may appear as the ultimate control of N input by N2 fixation. Because of the huge volume of water to consider, and because the SP Ocean is the place of intense denitrification in the east (N sink) and N2 fixation in the west (N source), precise seasonal C, N, P, and iron (Fe) budgets would be of prime interest to understand the efficiency, at the present time and in the future, of the oceanic biological carbon pump.

The Role of Natriuretic Agents In the Mechanism of Hypertension in the Dahl Strain of Salt-Sensitive and Salt-Resistant Rats

DTIC Science & Technology

1986-07-02

the pathogenesis of volume-dependent hypertension. OLHF, by inhibiting Na+ I - K+ pump activity in cardiovascular muscle cells , stimulates the...role of OLHF in hypertension •••••••••••••••••••• 18 Atrial Natriuretic Factor (ANF) ••.•••••••••••••••••••••• 19 Renal effects of atrial extracts...20 Vascular effects of ANF.... • . • • • • • • • • • • • • • • • • • • • • • • • 25 Primary structure and biological actions of

Seasonally different carbon flux changes in the Southern Ocean in response to the southern annular mode.

PubMed

Hauck, J; Völker, C; Wang, T; Hoppema, M; Losch, M; Wolf-Gladrow, D A

2013-12-01

Stratospheric ozone depletion and emission of greenhouse gases lead to a trend of the southern annular mode (SAM) toward its high-index polarity. The positive phase of the SAM is characterized by stronger than usual westerly winds that induce changes in the physical carbon transport. Changes in the natural carbon budget of the upper 100 m of the Southern Ocean in response to a positive SAM phase are explored with a coupled ecosystem-general circulation model and regression analysis. Previously overlooked processes that are important for the upper ocean carbon budget during a positive SAM period are identified, namely, export production and downward transport of carbon north of the polar front (PF) as large as the upwelling in the south. The limiting micronutrient iron is brought into the surface layer by upwelling and stimulates phytoplankton growth and export production but only in summer. This leads to a drawdown of carbon and less summertime outgassing (or more uptake) of natural CO 2 . In winter, biological mechanisms are inactive, and the surface ocean equilibrates with the atmosphere by releasing CO 2 . In the annual mean, the upper ocean region south of the PF loses more carbon by additional export production than by the release of CO 2 into the atmosphere, highlighting the role of the biological carbon pump in response to a positive SAM event.

The current status of fluoride salt cooled high temperature reactor (FHR) technology and its overlap with HIF target chamber concepts

NASA Astrophysics Data System (ADS)

Scarlat, Raluca O.; Peterson, Per F.

2014-01-01

The fluoride salt cooled high temperature reactor (FHR) is a class of fission reactor designs that use liquid fluoride salt coolant, TRISO coated particle fuel, and graphite moderator. Heavy ion fusion (HIF) can likewise make use of liquid fluoride salts, to create thick or thin liquid layers to protect structures in the target chamber from ablation by target X-rays and damage from fusion neutron irradiation. This presentation summarizes ongoing work in support of design development and safety analysis of FHR systems. Development work for fluoride salt systems with application to both FHR and HIF includes thermal-hydraulic modeling and experimentation, salt chemistry control, tritium management, salt corrosion of metallic alloys, and development of major components (e.g., pumps, heat exchangers) and gas-Brayton cycle power conversion systems. In support of FHR development, a thermal-hydraulic experimental test bay for separate effects (SETs) and integral effect tests (IETs) was built at UC Berkeley, and a second IET facility is under design. The experiments investigate heat transfer and fluid dynamics and they make use of oils as simulant fluids at reduced scale, temperature, and power of the prototypical salt-cooled system. With direct application to HIF, vortex tube flow was investigated in scaled experiments with mineral oil. Liquid jets response to impulse loading was likewise studied using water as a simulant fluid. A set of four workshops engaging industry and national laboratory experts were completed in 2012, with the goal of developing a technology pathway to the design and licensing of a commercial FHR. The pathway will include experimental and modeling efforts at universities and national laboratories, requirements for a component test facility for reliability testing of fluoride salt equipment at prototypical conditions, requirements for an FHR test reactor, and development of a pre-conceptual design for a commercial reactor.

Anticyclonic eddies are more productive than cyclonic eddies in subtropical gyres because of winter mixing.

PubMed

Dufois, François; Hardman-Mountford, Nick J; Greenwood, Jim; Richardson, Anthony J; Feng, Ming; Matear, Richard J

2016-05-01

Mesoscale eddies are ubiquitous features of ocean circulation that modulate the supply of nutrients to the upper sunlit ocean, influencing the rates of carbon fixation and export. The popular eddy-pumping paradigm implies that nutrient fluxes are enhanced in cyclonic eddies because of upwelling inside the eddy, leading to higher phytoplankton production. We show that this view does not hold for a substantial portion of eddies within oceanic subtropical gyres, the largest ecosystems in the ocean. Using space-based measurements and a global biogeochemical model, we demonstrate that during winter when subtropical eddies are most productive, there is increased chlorophyll in anticyclones compared with cyclones in all subtropical gyres (by 3.6 to 16.7% for the five basins). The model suggests that this is a consequence of the modulation of winter mixing by eddies. These results establish a new paradigm for anticyclonic eddies in subtropical gyres and could have important implications for the biological carbon pump and the global carbon cycle.

Value of pH regulators in the diagnosis, prognosis and treatment of cancer.

PubMed

Granja, Sara; Tavares-Valente, Diana; Queirós, Odília; Baltazar, Fátima

2017-04-01

Altered metabolism, associated with acidification of the extracellular milieu, is one of the major features of cancer. As pH regulation is crucial for the maintenance of all biological functions, cancer cells rely on the activity of lactate exporters and proton transporters to regulate their intracellular pH. The major players in cancer pH regulation are proton pump ATPases, sodium-proton exchangers (NHEs), monocarboxylate transporters (MCTs), carbonic anhydrases (CAs) and anion exchangers (AEs), which have been shown to be upregulated in several human malignancies. Thanks to the activity of the proton pumps and transporters, tumours acidify their microenvironment, becoming more aggressive and resistant to therapy. Thus, targeting tumour pH may contribute to more effective anticancer strategies for controlling tumour progression and therapeutic resistance. In the present study, we review the role of the main pH regulators expressed in human cancer cells, including their diagnostic and prognostic value, as well as their usefulness as therapeutic targets. Copyright © 2017 Elsevier Ltd. All rights reserved.

Passive solar nursing home for Northern Kentucky

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, J.G.; Ward, J.D.

This project is a 32-bed nursing home designed as an addition to an existing facility. Passive solar strategies included direct gain room windows and clerestories which admit light to phase change salt pouches in the ceilings of patient rooms. Corridors are skykighted; and the heating, ventilating, and conditioning system is comprised of water-source heat pumps and a 5000 gallon storage tank in conjunction with an air to air heat recovery wheel.

Box Model of a Series of Salt Ponds, as Applied to the Alviso Salt Pond Complex, South San Francisco Bay, California

USGS Publications Warehouse

Lionberger, Megan A.; Schoellhamer, David H.; Shellenbarger, Gregory; Orlando, James L.; Ganju, Neil K.

2007-01-01

This report documents the development and application of a box model to simulate water level, salinity, and temperature of the Alviso Salt Pond Complex in South San Francisco Bay. These ponds were purchased for restoration in 2003 and currently are managed by the U.S. Fish and Wildlife Service to maintain existing wildlife habitat and prevent a build up of salt during the development of a long-term restoration plan. The model was developed for the purpose of aiding pond managers during the current interim management period to achieve these goals. A previously developed box model of a salt pond, SPOOM, which calculates daily pond volume and salinity, was reconfigured to simulate multiple connected ponds and a temperature subroutine was added. The updated model simulates rainfall, evaporation, water flowing between the ponds and the adjacent tidal slough network, and water flowing from one pond to the next by gravity and pumps. Theoretical and measured relations between discharge and corresponding differences in water level are used to simulate most flows between ponds and between ponds and sloughs. The principle of conservation of mass is used to calculate daily pond volume and salinity. The model configuration includes management actions specified in the Interim Stewardship Plan for the ponds. The temperature subroutine calculates hourly net heat transfer to or from a pond resulting in a rise or drop in pond temperature and daily average, minimum, and maximum pond temperatures are recorded. Simulated temperature was compared with hourly measured data from pond 3 of the Napa?Sonoma Salt Pond Complex and monthly measured data from pond A14 of the Alviso Salt-Pond Complex. Comparison showed good agreement of measured and simulated pond temperature on the daily and monthly time scales.

Genome-wide expression profiling in leaves and roots of date palm (Phoenix dactylifera L.) exposed to salinity.

PubMed

Yaish, Mahmoud W; Patankar, Himanshu V; Assaha, Dekoum V M; Zheng, Yun; Al-Yahyai, Rashid; Sunkar, Ramanjulu

2017-03-22

Date palm, as one of the most important fruit crops in North African and West Asian countries including Oman, is facing serious growth problems due to salinity, arising from persistent use of saline water for irrigation. Although date palm is a relatively salt-tolerant plant species, its adaptive mechanisms to salt stress are largely unknown. In order to get an insight into molecular mechanisms of salt tolerance, RNA was profiled in leaves and roots of date palm seedlings subjected to NaCl for 10 days. Under salt stress, photosynthetic parameters were differentially affected; all gas exchange parameters were decreased but the quantum yield of PSII was unaffected while non-photochemical quenching was increased. Analyses of gene expression profiles revealed 2630 and 4687 genes were differentially expressed in leaves and roots, respectively, under salt stress. Of these, 194 genes were identified as commonly responding in both the tissue sources. Gene ontology (GO) analysis in leaves revealed enrichment of transcripts involved in metabolic pathways including photosynthesis, sucrose and starch metabolism, and oxidative phosphorylation, while in roots genes involved in membrane transport, phenylpropanoid biosynthesis, purine, thiamine, and tryptophan metabolism, and casparian strip development were enriched. Differentially expressed genes (DEGs) common to both tissues included the auxin responsive gene, GH3, a putative potassium transporter 8 and vacuolar membrane proton pump. Leaf and root tissues respond differentially to salinity stress and this study has revealed genes and pathways that are associated with responses to elevated NaCl levels and thus may play important roles in salt tolerance providing a foundation for functional characterization of salt stress-responsive genes in the date palm.

Long-Term Patterns in Production and Export of Fecal Pellets by Krill and Salps along the Western Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Steinberg, D. K.; Ruck, K. E.; Cope, J. S.

2016-02-01

The Western Antarctic Peninsula (WAP) is one of the most rapidly warming regions on Earth, and where climate-induced changes in zooplankton abundance and species composition could dramatically affect the pelagic food web and biogeochemical cycling. We examined long-term (1993 to the present) and spatial trends in summer abundance of, and fecal pellet production (FPP) by, Antarctic krill (Euphausia superba) and gelatinous salps (Salpa thompsoni) and their relationship with physical and other environmental parameters. Zooplankton were collected as part of the Palmer, Antarctica Long-Term Ecological Research Program (PAL LTER) from the epipelagic zone in a region divided into latitudinal (North, South, and Far South) and cross-shelf (coastal, shelf, slope) sub-regions. Beginning in 2009, FPP and sinking rate experiments were conducted at representative stations along these gradients. FPP peaks occurred every 4-6 years in both species in the north and south, but alternated such that some years were characterized by high krill-mediated export, and others by high salp-mediated export. In the far south (where perennial sea ice still persists), and in both coastal and shelf sub-regions, krill FFP exceeded that of salps. Conversely, off the slope, salp FPP exceeded that of krill. Variability in krill FPP was strongly and positively influenced by primary production 2-years prior, and negatively correlated with sea surface temperature (no lag). Salp FPP was most significantly correlated with sea ice parameters, with highest FPP in years of lowest sea-ice extent, duration, and area. Warmer water and ice-free conditions favored salps over krill, which also increased overall potential export of fecal pellet carbon to depth. We discuss the implications of this potential increase in biological pump efficiency as the climate warms.

Mechanisms for the export of archaeal lipids down the water column in the upwelling area off Cape Blanc, North-West Africa

NASA Astrophysics Data System (ADS)

Ebersbach, Friederike; Goldenstein, Nadine; Iversen, Morten; Mollenhauer, Gesine; Hinrichs, Kai-Uwe

2016-04-01

Transport mechanisms of microbial membrane lipids from surface waters to the seafloor are poorly understood. In particular, pelagic archaeal glycerol dibiphytanyl glycerol tetraethers (GDGTs) from planktonic archaea are frequently used for reconstruction of ancient sea surface temperatures (Schouten et al. 2013). Because planktonic archaea are too small and neutrally buoyant to sink independently, transport vehicles for efficient export of fossil archaeal biomarkers to the sediment are required. The surface ocean is coupled with the deep ocean through biogenic sinking particles, a process known as the biological pump (Volk and Hoffert 1985). Two different pathways for particle formation, mainly taking place in the mesopelagic zone, are distinguished: Direct aggregation of phytoplankton blooms or grazing, resulting in phyto-detrital aggregates or reprocessed faecal material, respectively. Grazing and packaging into sinking particles is a possible export mechanism for GDGTs (Huguet et al. 2006). Moreover, it is assumed that phyto-detrital aggregates also play an important role in transporting GDGTs to the deep (Mollenhauer et al. 2015), but processes behind this pathway remain unclear. However, there are only few studies that link GDGT signals in sinking particles to the composition of the exported particulate matter (e.g. Yamamoto et al., 2012; Mollenhauer et al. 2015). Here we investigate sinking particles and suspended particulate matter (SPM) from spring blooms in 2012 and 2013 in the upwelling region in the Atlantic Ocean off Cape Blanc, Mauritania. We compare for the first time material from free-floating sediment traps (100, 200 and 400 m; purely sinking particles) with sinking particles and SPM from size fractionated in-situ pump (ISP) filters (several depths between 40 and 2350 m). This setup allows to relate the signal from archaeal lipids to (i) the flux of particulate organic carbon and the particle assemblages as revealed by the characterisation of thousands of individual particles collected in gels in addition to (ii) the sinking particles and SPM present in different particle size fractions on the filters. First results show that the large size fraction carries relatively more intact lipids indicating fresh material being attached to sinking particles rather than suspended in the water column. Furthermore, the distribution of 1G-GDGTs over depths differs from that of 2G- and HPH-GDGTs which might relate to different archaeal communities at different depths. Our findings contribute to the mechanistic understanding of the export of organic molecules through the water column and support the validation of lipid-based paleoceanographic proxies. References Huguet, C., Cartes, J.E., Sinninghe Damsté, J.S., Schouten, S., 2006. Marine crenarchaeotal membrane lipids in decapods: Implications for the TEX86 paleothermometer. Geochemistry, Geophysics, Geosystems 7 (11), Q11010. Mollenhauer, G., Basse, A., Kim, J.-H., Sinninghe Damsté, J.S., Fischer, G., 2015. A four-year record of UK'37- and TEX86-derived sea surface temperature estimates from sinking particles in the filamentous upwelling region off Cape Blanc, Mauritania. Deep Sea Research Part I: Oceanographic Research Papers 97, 67-79. doi:10.1016/j.dsr.2014.11.015 Schouten, S., Hopmans, E.C., Sinninghe Damsté, J.S., 2013. The organic geochemistry of glycerol dialkyl glycerol tetraether lipids: A review. Organic Geochemistry 54, 19-61. Volk, T., Hoffert, M.I., 1985. Ocean carbon pumps: analysis of relative strengths and efficiencies in ocean-driven atmospheric CO2 changes. Geophysical Monographs 32, 99-110. Yamamoto, M., Shimamoto, A., Fukuhara, T., Tanaka, Y., Ishizaka, J., 2012. Glycerol dialkyl glycerol tetraethers and TEX86 index in sinking particles in the western North Pacific. Organic Geochemistry 53 (0), 52-62.

Implications of Tidally Varying Bed Stress and Intermittent Estuarine Stratification on Fine-Sediment Dynamics through the Mekong's Tidal River to Estuarine Reach

NASA Astrophysics Data System (ADS)

McLachlan, R. L.; Ogston, A. S.; Allison, M. A.; Hilmo, R. S.

2016-12-01

Widely varying ratios of marine to freshwater influence within near-mouth distributaries have impacts on sedimentary processes within the lower river that have yet to be thoroughly characterized. These impacts are of particular interest because river gauging stations are often above the river-estuary interface and, therefore, may not accurately characterize sediment flux through the lower river. Flow velocity, salinity, and suspended sediment properties (concentration, particle size, and settling velocity) were measured within the tidal Sông Hu distributary of the lower Mekong River, Vietnam during both high and low river discharge seasons. Seasonal variations in river discharge and estuarine regime resulted in export of fine sediment when discharge was high ( 1.7 t s-1) and import when discharge was low ( 0.25 t s-1). Generally, the estuary moved in and out of 40 km of the lower distributary with discharge and tidal phase, and the estuary exhibited salt wedge to partially-mixed conditions. High river discharge and neap tides increased stratification of salinity and suspended sediment. Suspended sediment was influenced by seasonal and tidal fluctuations in near-bed shear stress and the intermittent presence of a protective salt wedge and associated estuary turbidity maximum. This fluctuating flow and salinity regime induced variations in flocculation, settling, and trapping of sediment within the river channel. Above the estuary, particles were pre-flocculated, and within and near the estuary, increased flocculation promoted particle settling. The degree of aggregation and settling velocity of suspended particles were largest during ebb tides of high river discharge and during flood tides of low river discharge. Sediment deposited on the river bed was protected from resuspension by lowered bed stress within and near the salt wedge. These patterns promote retention of mud in the lower river when estuarine processes exist and mud export when fluvial processes dominate. The spectrum of present conditions analyzed collaboratively with field studies, remotely sensed observations, and modeling has shed light on how this environment, and other large tropical deltas, will react to changing magnitudes of fluvial and marine influences due to sea-level rise and anthropogenic alterations to the delta.

Glacial-interglacial atmospheric CO2 change: a possible "standing volume" effect on deep-ocean carbon sequestration

NASA Astrophysics Data System (ADS)

Skinner, L. C.

2009-09-01

So far, the exploration of possible mechanisms for glacial atmospheric CO2 drawdown and marine carbon sequestration has tended to focus on dynamic or kinetic processes (i.e. variable mixing-, equilibration- or export rates). Here an attempt is made to underline instead the possible importance of changes in the standing volumes of intra-oceanic carbon reservoirs (i.e. different water-masses) in influencing the total marine carbon inventory. By way of illustration, a simple mechanism is proposed for enhancing the marine carbon inventory via an increase in the volume of relatively cold and carbon-enriched deep water, analogous to modern Lower Circumpolar Deep Water (LCDW), filling the ocean basins. A set of simple box-model experiments confirm the expectation that a deep sea dominated by an expanded LCDW-like watermass holds more CO2, without any pre-imposed changes in ocean overturning rate, biological export or ocean-atmosphere exchange. The magnitude of this "standing volume effect" (which operates by boosting the solubility- and biological pumps) might be as large as the contributions that have previously been attributed to carbonate compensation, terrestrial biosphere reduction or ocean fertilisation for example. By providing a means of not only enhancing but also driving changes in the efficiency of the biological- and solubility pumps, this standing volume mechanism may help to reduce the amount of glacial-interglacial CO2 change that remains to be explained by other mechanisms that are difficult to assess in the geological archive, such as reduced mass transport or mixing rates in particular. This in turn could help narrow the search for forcing conditions capable of pushing the global carbon cycle between glacial and interglacial modes.

Conserved Allosteric Hot Spots in the Transmembrane Domains of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Channels and Multidrug Resistance Protein (MRP) Pumps*

PubMed Central

Wei, Shipeng; Roessler, Bryan C.; Chauvet, Sylvain; Guo, Jingyu; Hartman, John L.; Kirk, Kevin L.

2014-01-01

ATP-binding cassette (ABC) transporters are an ancient family of transmembrane proteins that utilize ATPase activity to move substrates across cell membranes. The ABCC subfamily of the ABC transporters includes active drug exporters (the multidrug resistance proteins (MRPs)) and a unique ATP-gated ion channel (cystic fibrosis transmembrane conductance regulator (CFTR)). The CFTR channel shares gating principles with conventional ligand-gated ion channels, but the allosteric network that couples ATP binding at its nucleotide binding domains (NBDs) with conformational changes in its transmembrane helices (TMs) is poorly defined. It is also unclear whether the mechanisms that govern CFTR gating are conserved with the thermodynamically distinct MRPs. Here we report a new class of gain of function (GOF) mutation of a conserved proline at the base of the pore-lining TM6. Multiple substitutions of this proline promoted ATP-free CFTR activity and activation by the weak agonist, 5′-adenylyl-β,γ-imidodiphosphate (AMP-PNP). TM6 proline mutations exhibited additive GOF effects when combined with a previously reported GOF mutation located in an outer collar of TMs that surrounds the pore-lining TMs. Each TM substitution allosterically rescued the ATP sensitivity of CFTR gating when introduced into an NBD mutant with defective ATP binding. Both classes of GOF mutations also rescued defective drug export by a yeast MRP (Yor1p) with ATP binding defects in its NBDs. We conclude that the conserved TM6 proline helps set the energy barrier to both CFTR channel opening and MRP-mediated drug efflux and that CFTR channels and MRP pumps utilize similar allosteric mechanisms for coupling conformational changes in their translocation pathways to ATP binding at their NBDs. PMID:24876383

Conserved allosteric hot spots in the transmembrane domains of cystic fibrosis transmembrane conductance regulator (CFTR) channels and multidrug resistance protein (MRP) pumps.

PubMed

Wei, Shipeng; Roessler, Bryan C; Chauvet, Sylvain; Guo, Jingyu; Hartman, John L; Kirk, Kevin L

2014-07-18

ATP-binding cassette (ABC) transporters are an ancient family of transmembrane proteins that utilize ATPase activity to move substrates across cell membranes. The ABCC subfamily of the ABC transporters includes active drug exporters (the multidrug resistance proteins (MRPs)) and a unique ATP-gated ion channel (cystic fibrosis transmembrane conductance regulator (CFTR)). The CFTR channel shares gating principles with conventional ligand-gated ion channels, but the allosteric network that couples ATP binding at its nucleotide binding domains (NBDs) with conformational changes in its transmembrane helices (TMs) is poorly defined. It is also unclear whether the mechanisms that govern CFTR gating are conserved with the thermodynamically distinct MRPs. Here we report a new class of gain of function (GOF) mutation of a conserved proline at the base of the pore-lining TM6. Multiple substitutions of this proline promoted ATP-free CFTR activity and activation by the weak agonist, 5'-adenylyl-β,γ-imidodiphosphate (AMP-PNP). TM6 proline mutations exhibited additive GOF effects when combined with a previously reported GOF mutation located in an outer collar of TMs that surrounds the pore-lining TMs. Each TM substitution allosterically rescued the ATP sensitivity of CFTR gating when introduced into an NBD mutant with defective ATP binding. Both classes of GOF mutations also rescued defective drug export by a yeast MRP (Yor1p) with ATP binding defects in its NBDs. We conclude that the conserved TM6 proline helps set the energy barrier to both CFTR channel opening and MRP-mediated drug efflux and that CFTR channels and MRP pumps utilize similar allosteric mechanisms for coupling conformational changes in their translocation pathways to ATP binding at their NBDs. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

NMR studies on Na+ transport in Synechococcus PCC 6311

NASA Technical Reports Server (NTRS)

Nitschmann, W. H.; Packer, L.

1992-01-01

The freshwater cyanobacterium Synechococcus PCC 6311 is able to adapt to grow after sudden exposure to salt (NaCl) stress. We have investigated the mechanism of Na+ transport in these cells during adaptation to high salinity. Na+ influx under dark aerobic conditions occurred independently of delta pH or delta psi across the cytoplasmic membrane, ATPase activity, and respiratory electron transport. These findings are consistent with the existence of Na+/monovalent anion cotransport or simultaneous Na+/H+ +anion/OH- exchange. Na+ influx was dependent on Cl-, Br-, NO3-, or NO2-. No Na+ uptake occurred after addition of NaI, NaHCO3, or Na2SO4. Na+ extrusion was absolutely dependent on delta pH and on an ATPase activity and/or on respiratory electron transport. This indicates that Na+ extrusion via Na+/H+ exchange is driven by primary H+ pumps in the cytoplasmic membrane. Cells grown for 4 days in 0.5 m NaCl medium, "salt-grown cells," differ from control cells by a lower maximum velocity of Na+ influx and by lower steady-state ratios of [Na+]in/[Na+]out. These results indicate that cells grown in high-salt medium increase their capacity to extrude Na+. During salt adaptation Na+ extrusion driven by respiratory electron transport increased from about 15 to 50%.

Carbon export in the naturally iron-fertilized Kerguelen area of the Southern Ocean based on the 234Th approach

NASA Astrophysics Data System (ADS)

Planchon, F.; Ballas, D.; Cavagna, A.-J.; Bowie, A. R.; Davies, D.; Trull, T.; Laurenceau-Cornec, E. C.; Van Der Merwe, P.; Dehairs, F.

2015-06-01

This study examined upper-ocean particulate organic carbon (POC) export using the 234Th approach as part of the second KErguelen Ocean and Plateau compared Study expedition (KEOPS2). Our aim was to characterize the spatial and the temporal variability of POC export during austral spring (October-November 2011) in the Fe-fertilized area of the Kerguelen Plateau region. POC export fluxes were estimated at high productivity sites over and downstream of the plateau and compared to a high-nutrient low-chlorophyll (HNLC) area upstream of the plateau in order to assess the impact of iron-induced productivity on the vertical export of carbon. Deficits in 234Th activities were observed at all stations in surface waters, indicating early scavenging by particles in austral spring. 234Th export was lowest at the reference station R-2 and highest in the recirculation region (E stations) where a pseudo-Lagrangian survey was conducted. In comparison 234Th export over the central plateau and north of the polar front (PF) was relatively limited throughout the survey. However, the 234Th results support that Fe fertilization increased particle export in all iron-fertilized waters. The impact was greatest in the recirculation feature (3-4 fold at 200 m depth, relative to the reference station), but more moderate over the central Kerguelen Plateau and in the northern plume of the Kerguelen bloom (~2-fold at 200 m depth). The C : Th ratio of large (>53 μm) potentially sinking particles collected via sequential filtration using in situ pumping (ISP) systems was used to convert the 234Th flux into a POC export flux. The C : Th ratios of sinking particles were highly variable (3.1 ± 0.1 to 10.5 ± 0.2 μmol dpm-1) with no clear site-related trend, despite the variety of ecosystem responses in the fertilized regions. C : Th ratios showed a decreasing trend between 100 and 200 m depth suggesting preferential carbon loss relative to 234Th possibly due to heterotrophic degradation and/or grazing activity. C : Th ratios of sinking particles sampled with drifting sediment traps in most cases showed very good agreement with ratios for particles collected via ISP deployments (>53 μm particles). Carbon export production varied between 3.5 ± 0.9 and 11.8 ± 1.3 mmol m-2 d-1 from the upper 100 m and between 1.8 ± 0.9 and 8.2 ± 0.9 mmol m-2 d-1 from the upper 200 m. The highest export production was found inside the PF meander with a range of 5.3 ± 1.0 to 11.8 ± 1.1 mmol m-2 d-1 over the 19-day survey period. The impact of Fe fertilization is highest inside the PF meander with 2.9-4.5-fold higher carbon flux at 200 m depth in comparison to the HNLC control station. The impact of Fe fertilization was significantly less over the central plateau (stations A3 and E-4W) and in the northern branch of the bloom (station F-L) with 1.6-2.0-fold higher carbon flux compared to the reference station R. Export efficiencies (ratio of export to primary production and ratio of export to new production) were particularly variable with relatively high values in the recirculation feature (6 to 27 %, respectively) and low values (1 to 5 %, respectively) over the central plateau (station A3) and north of the PF (station F-L), indicating spring biomass accumulation. Comparison with KEOPS1 results indicated that carbon export production is much lower during the onset of the bloom in austral spring than during the peak and declining phases in late summer.

Technical Analysis of In-Valley Drainage Management Strategies for the Western San Joaquin Valley, California

USGS Publications Warehouse

Presser, Theresa S.; Schwarzbach, Steven E.

2008-01-01

The western San Joaquin Valley is one of the most productive farming areas in the United States, but salt-buildup in soils and shallow groundwater aquifers threatens this area?s productivity. Elevated selenium concentrations in soils and groundwater complicate drainage management and salt disposal. In this document, we evaluate constraints on drainage management and implications of various approaches to management considered in: *the San Luis Drainage Feature Re-Evaluation (SLDFRE) Environmental Impact Statement (EIS) (about 5,000 pages of documentation, including supporting technical reports and appendices); *recent conceptual plans put forward by the San Luis Unit (SLU) contractors (i.e., the SLU Plans) (about 6 pages of documentation); *approaches recommended by the San Joaquin Valley Drainage Program (SJVDP) (1990a); and *other U.S. Geological Survey (USGS) models and analysis relevant to the western San Joaquin Valley. The alternatives developed in the SLDFRE EIS and other recently proposed drainage plans (refer to appendix A for details) differ from the strategies proposed by the San Joaquin Valley Drainage Program (1990a). The Bureau of Reclamation (USBR) in March 2007 signed a record of decision for an in-valley disposal option that would retire 194,000 acres of land, build 1,900 acres of evaporation ponds, and develop a treatment system to remove salt and selenium from drainwater. The recently proposed SLU Plans emphasize pumping drainage to the surface, storing approximately 33% in agricultural water re-use areas, treating selenium through biotechnology, enhancing the evaporation of water to concentrate salt, and identifying ultimate storage facilities for the remaining approximately 67% of waste selenium and salt. The treatment sequence of reuse, reverse osmosis, selenium bio-treatment, and enhanced solar evaporation is unprecedented and untested at the scale needed to meet plan requirements. All drainage management strategies that have been proposed seek to reduce the amount of drainage water produced. One approach is to reduce the amount of drainage per irrigated acre. From modeling simulations performed for the SLDFRE EIS of the Westlands Area of the SLU, theoretical minimums that can be achieved range from approximately 0.16 to 0.25 acre-feet per acre per year (AF/acre/year). Minimum production rates from the Northerly Area of the SLU are theorized as being much higher, approximately 0. 42 to 0.28 AF/acre/year. Rates shown in the SLU Plans for drained acres from the two areas combined are 0.5 AF/acre/year at the subsurface drain stage and 0.37 AF/acre/year after a series of on-farm and regional measures are instituted. Land retirement is a key strategy to reduce drainage because it can effectively reduce drainage to zero if all drainage-impaired lands are retired. Land retirement alternatives considered in the SLDFRE EIS differ for the two areas analyzed in the SLU. The Northerly Area is to retire a nominal 10,000 acres and Westlands is to retire up to 300,000 acres. The initial land retirement option recently put forth in the SLU Plans predicted drainage volume reductions that are consistent with 200,000 acres of land retirement, but only 100,000 acres of land retirement was proposed. Within the proposed area of drainage there are, for all practical purposes, unlimited reservoirs of selenium and salt stored within the aquifers and soils of the valley and upslope in the Coast Ranges. Salt imported in irrigation water is estimated to be at least 1.5 million tons per year for the Westlands and Northerly Areas (SJVDIP, 1998). Analysis of the land retirement alternatives presented in the SLDFRE EIS indicates that land retirement of a minimum of only 100,000 acres results in the annual pumping to the surface of 20,142 pounds of selenium or about a million pounds of selenium over a 50 year period. Retiring 200,000 acres results in an annual pumping of 14,750 pounds of selenium; and reti

Spatiotemporal Variability in Particulate Organic Carbon Export Observed Using Bio-Optical Profiling Floats

NASA Astrophysics Data System (ADS)

Estapa, M. L.

2016-02-01

Autonomous, bio-optical profiling floats are poised to broaden the number and spatiotemporal resolution of observations of the ocean's biological pump. Here, we used multiple optical sensors aboard two bio-optical profiling floats (Navis BGCi, Sea-Bird) deployed in the Sargasso Sea to derive in situ proxies for particulate carbon (PC) flux, sub-mixed layer net community production (NCP) and to drive a model of net primary production (NPP). Profiles were collected at approximately 2-day resolution, and drift-phase PC flux observations were collected at subdaily resolution at a rotating cycle of observation depths between 150 and 1000 m. The magnitudes of NPP, PC flux, and their annually-averaged ratio were generally consistent with observations at the nearby Bermuda Atlantic Timeseries Study (BATS) site. PC flux and the export ratio were enhanced in the autumn as well as in the spring, and varied over short timescales possibly due to the influence of mesoscale eddies. The relatively shallow park depths and short profile cycle lengths allow us to identify ephemeral, subsurface bio-optical features and compare them to measured fluxes and satellite-observed surface properties.

Heat transfer experiments with a central receiver tube subjected to unsteady and non-uniform heat flux

NASA Astrophysics Data System (ADS)

Fernández-Torrijos, María; Marugán-Cruz, Carolina; Sobrino, Celia; Santana, Domingo

2017-06-01

In this work, a molten salt test loop to study the heat transfer process in external molten salt receivers is described. The experimental installation is formed by a cylindrical molten salt tank, a pump, a flow meter, and an induction heater to generate the heat flux, which is applied in a small rectangular region of the tube surface. In central tower plants, the external receiver pipe is considered to be under unilateral concentrated solar radiation, because only one side of the pipe receives high heat flux. The main advantage of using an induction heater is the control of heating in different areas of the tube. In order to measure the effects of a non-homogenous and unsteady heat flux on the wall temperature distribution a series of experiments have been carried out. 4 K-type thermocouples have been welded at different axial and azimuthal positions of the pipe to obtain the wall temperature distribution. Different temperature measurements have been made varying the heat flux and water velocity to study their effects on the heat transfer process.

Origin and evolution of osmoregulatory mechanisms in blue-green algae (cyanobacteria) as a function of metabolic and structural complexity: Reflections of Precambrian paleobiology

NASA Technical Reports Server (NTRS)

Yopp, John H.; Tindall, Donald R.; Pavlicek, Kenneth

1987-01-01

Major accomplishments underlying the basic understanding of cyanobacterial resistance to salt tolerance and osmotic stress were made. The methodology proposed included: the tracing of the pathways of formation of osmoregulatory solutes by traditional methods involving C-14 labelled substrates; gas chromatography; amino acid analysis; X-ray analysis using scanning transmission electron microscopy; and most importantly, C-13 labelled substrates, followed by Nuclear Magnetic Resonance (NMR) spectroscopy. It was found that the cyanobacteria employ a diversity of organic, osmoregulatory solutes. Osmoregulatory solutes were found to serve four functions: adjustment of water activity, noninhibition of enzymes; lowering of K sub m of enzymes to allow functioning at normal levels when the intracellular salt accumulates, and extending the pH optimum of enzymes as intracellular pH rises due to proton-potassium ion pump action during osmoregulation. Differences in osmoregulatory solutes may, but are not always, be attributed to differences in nutritional capabilities. The mechanism of osmoregulation and concomitant salt tolerance in halophilic cyanobacteria was elucidated. The activities of betaine and S-Adenosylhomocysteine hydrolase are discussed.

Tidally averaged water and salt transport velocities and their distributions in the Pearl River Estuary

NASA Astrophysics Data System (ADS)

Zhu, Shouxian; Sheng, Jinyu; Ji, Xiaomei

2016-09-01

Tidally averaged transports of water and substance are important physical quantities over estuarine, coastal, and shelf waters, but they have been indistinguishably expressed in terms of the Eulerian residual current (ERC) or Lagrangian residual current (LRC) in many previous studies. In this study, the tidally averaged transport velocities for water (TA-WTV) and substance (TA-STV) are considered based on residual fluxes. The main advantage of these newly defined transport velocities is that they can be used to quantify differences in amplitude and direction between the tidally averaged water and substance transports. The two-dimensional TA-STV is interpreted as the transport due to the residual flow of water, tidal pumping, and vertical shear. The three-dimensional TA-STV includes transports from the residual flow of water and tidal pumping. Numerical results of sea surface elevations, currents, and salinity produced by a triply nested coastal ocean model for the Pearl River Estuary (PRE) are used to calculate the TA-WTV and TA-STV for salt (TA-STVsa). The general features of the TA-WTV and TA-STVsa are similar over the most part of the PRE but differ significantly in amplitude and direction over the salinity frontal zone. The ERC and LRC calculated from model results are also significantly different from the TA-STVsa over the salinity frontal zone.

Salt-losing nephropathy in hypothyroidism.

PubMed

Bautista, Aileen Azul; Duya, Jose Eduardo De Leon; Sandoval, Mark Anthony Santiago

2014-05-21

A 35-year-old man presented with recurrent lower extremity weakness associated with polyuria later progressing to generalised weakness with difficulty in breathing. The patient was hypotensive and dry, with normal thyroid and chest examination, weak lower extremity and carpopedal spasm. Workup revealed hypokalaemia, hyponatraemia, hypocalcaemia, hypomagnesaemia, hypochloraemia and hypophosphataemia. Arterial blood gas showed respiratory alkalosis with good oxygenation. Twenty-four-hour urine collection showed normal volume with electrolyte wasting. Thyroid function test revealed overt hypothyroidism with negative antithyroid peroxidase. The patient was well after treatment with levothyroxine, volume and electrolyte replacement and was discharged. Thyroid hormones are related to the expression of the Na-K-ATPase, Na-Pi cotransporter, Mg-ATPase and Na-Ca exchanger pumps in the renal tubules. Sodium, potassium, phosphate, calcium, magnesium and water losses result from decreased expression of these pumps. 2014 BMJ Publishing Group Ltd.

Modeling Dissolved Solids in the Rincon Valley, New Mexico Using RiverWare

NASA Astrophysics Data System (ADS)

Abudu, S.; Ahn, S. R.; Sheng, Z.

2017-12-01

Simulating transport and storage of dissolved solids in surface water and underlying alluvial aquifer is essential to evaluate the impacts of surface water operations, groundwater pumping, and climate variability on the spatial and temporal variability of salinity in the Rio Grande Basin. In this study, we developed a monthly RiverWare water quantity and quality model to simulate the both concentration and loads of dissolved solids for the Rincon Valley, New Mexico from Caballo Reservoir to Leasburg Dam segment of the Rio Grande. The measured flows, concentration and loads of dissolved solids in the main stream and drains were used to develop RiveWare model using 1980-1988 data for calibration, and 1989-1995 data for validation. The transport of salt is tracked using discretized salt and post-process approaches. Flow and salt exchange between the surface water and adjacent groundwater objects is computed using "soil moisture salt with supplemental flow" method in the RiverWare. In the groundwater objects, the "layered salt" method is used to simulate concentration of the dissolved solids in the shallow groundwater storage. In addition, the estimated local inflows under different weather conditions by using a calibrated Soil Water Assessment Tool (SWAT) were fed into the RiverWare to refine the simulation of the flow and dissolved solids. The results show the salt concentration and loads increased at Leasburg Dam, which indicates the river collects salts from the agricultural return flow and the underlying aquifer. The RiverWare model with the local inflow fed by SWAT delivered the better quantification of temporal and spatial salt exchange patterns between the river and the underlying aquifer. The results from the proposed modeling approach can be used to refine the current mass-balance budgets for dissolved-solids transport in the Rio Grande, and provide guidelines for planning and decision-making to control salinity in arid river environment.

Factors affecting water quality and net flux of solutes in two stream basins in the Quabbin Reservoir drainage basin, central Massachusetts,1983-85

USGS Publications Warehouse

Rittmaster, R.L.; Shanley, J.B.

1995-01-01

The factors that affect stream-water quality were studied at West Branch Swift River (Swift River), and East Branch Fever Brook (Fever Brook), two forested watersheds that drain into the Quabbin Reservoir, central Massachusetts, from December 1983 through August 1985. Spatial and temporal variations of chemistry of precipitation, surface water; and ground water and the linkages between chemical changes and hydrologic processes were used to identify the mechanisms that control stream chemistry. Precipitation chemistry was dominated by hydrogen ion (composite p.H 4.23), sulfate, and nitrate. Inputs of hydrogen and nitrate from pre- cipitation were almost entirely retained in the basins, whereas input of sulfate was approximately balanced by export by streamflow draining the basins. Both streams were poorly buffered, with mean pH near 5.7, mean alkalinity less than 30 microequivalents per liter, and sulfate concen- trations greater than 130 microequivalents per liter. Sodium and chloride, derived primarily from highway deicing salts, were the dominant solutes at Fever Brook. After adjustments for deicing salts, fluxes of base cations during the 21-month study were 2,014 and 1,429 equivalents per hectare in Swift River and Fever Brook, respectively. Base cation fluxes were controlled primarily by weathering of hornblende (Fever Brook) and plagioclase (Swift River). The overall weathering rate was greater in the Swift River Basin because easily weathered gabbro underlies one subbasin which comprises 11.2 percent of the total basin area but contributed about 77 percent of the total alkalinity. Alkalinity export was nearly equal in the two basins, however, because some alkalinity was generated in wetlands in the Fever Brook Basin through bacterial sulfate reduction coupled with organic-carbon oxidation.

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

DOE PAGES

Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.; ...

2016-09-23

Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF aand RsaF b, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrug effluxmore » pumps. Here we provide evidence that, unlike TolC, RsaF aand RsaF bare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF aand RsaF bare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF aand RsaF bled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF aand RsaF bled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF aand RsaF bin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels inC. crescentus. IMPORTANCEDecreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.

ABSTRACT Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF aand RsaF b, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrugmore » efflux pumps. Here we provide evidence that, unlike TolC, RsaF aand RsaF bare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF aand RsaF bare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF aand RsaF bled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF aand RsaF bled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF aand RsaF bin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels inC. crescentus. IMPORTANCEDecreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.

Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.Caulobacter crescentusis unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF aand RsaF b, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology toEscherichia coliTolC, the outer membrane channel of multidrug effluxmore » pumps. Here we provide evidence that, unlike TolC, RsaF aand RsaF bare not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF aand RsaF bare required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF aand RsaF bled to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF aand RsaF bled to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF aand RsaF bin cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels inC. crescentus. IMPORTANCEDecreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

Contribution of urban runoff in Taipei metropolitan area to dissolved inorganic nitrogen export in the Danshui River, Taiwan.

PubMed

Kuo, Nae-Wen; Jien, Shih-Hao; Hong, Nien-Ming; Chen, Yao-Te; Lee, Tsung-Yu

2017-01-01

A previous study has demonstrated that Danshui River has almost the highest dissolved inorganic nitrogen (DIN) yield in the world and exports most of the DIN in the form of ammonium unlike the world's large rivers. However, the DIN sources are poorly constrained. In this study, the contributions of major sources in the Taipei metropolitan area to the DIN export in the Danshui River were investigated. It is observed that ammonium is the major DIN species in the downstream reaches, resulting from the ammonium-dominated inputs of the effluents of wastewater treatment plants (WWTP) and rain water pumping stations (RWPS). DIN concentrations in the downstream (urban) reaches are substantially elevated. The upstream tributaries annually discharge ∼2709 t DIN to the downstream reaches. However, the DIN discharge off the downstream reaches rises to ∼17,918 t, resulting from the contribution of RWPS-collected water, i.e., ∼14,632 t, and the effluents of two WWTP, i.e., ∼577 t. RWPS-collected water inherently contains the contribution of atmospheric deposition, ∼2937 t DIN. This finding implies that ∼11,695 t (∼66 % of the downstream output) DIN flux off the Danshui River is from urban runoff and can be attributed to human activities in the Taipei metropolitan area. To improve the water quality in the Danshui River, water quality controls in urban runoff are important.

Osa Topical Meeting Proceedings (4th) on Picosecond Electronics and Optoelectronics Held in Salt Lake City, Utah on 13-15 March 1991. Volume 9

DTIC Science & Technology

1992-05-22

profile shoot effect critically depends on the field, therefore is modified by the presence of the pump beam, and we nonuniform fields smear out the...different electrical signal with a different rise and decay ing and intervalley scattering with a nonuniform electric time. The total displacement...current is approximately field and nonuniform carrier injection in one dimension. the sum of the individual current sources. The net result We take a

12. VIEW OF WESTERN CANAL AT ALMA SCHOOL ROAD IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. VIEW OF WESTERN CANAL AT ALMA SCHOOL ROAD IN MESA, THE LOCATION AT WHICH THE PECK, PINE AND WALLACE FEEDERS FORMERLY JOINED TO FORM THE WESTERN CANAL. THE PECK AND PINE FEEDERS, NOW KNOWN AS LATERAL 9 AND LATERAL 10, AND ALMOST ENTIRELY PIPED, STILL JOIN THE WESTERN CANAL AT THIS POINT, BUT AN EQUALLY IMPORTANT SOURCE OF SUPPLY IS THE NUMEROUS GROUNDWATER PUMPS LOCATED ON THE SYSTEM. - Western Canal, South side of Salt River between Tempe, Phoenix & Mesa, Mesa, Maricopa County, AZ

Molten Chloride Salts for Heat Transfer in Nuclear Systems

NASA Astrophysics Data System (ADS)

Ambrosek, James Wallace

2011-12-01

A forced convection loop was designed and constructed to examine the thermal-hydraulic performance of molten KCl-MgCl2 (68-32 at %) salt for use in nuclear co-generation facilities. As part of this research, methods for prediction of the thermo-physical properties of salt mixtures for selection of the coolant salt were studied. In addition, corrosion studies of 10 different alloys were exposed to the KCl-MgCl2 to determine a suitable construction material for the loop. Using experimental data found in literature for unary and binary salt systems, models were found, or developed to extrapolate the available experimental data to unstudied salt systems. These property models were then used to investigate the thermo-physical properties of the LINO3-NaNO3-KNO 3-Ca(NO3), system used in solar energy applications. Using these models, the density, viscosity, adiabatic compressibility, thermal conductivity, heat capacity, and melting temperatures of higher order systems can be approximated. These models may be applied to other molten salt systems. Coupons of 10 different alloys were exposed to the chloride salt for 100 hours at 850°C was undertaken to help determine with which alloy to construct the loop. Of the alloys exposed, Haynes 230 had the least amount of weight loss per area. Nickel and Hastelloy N performed best based on maximum depth of attack. Inconel 625 and 718 had a nearly uniform depletion of Cr from the surface of the sample. All other alloys tested had depletion of Cr along the grain boundaries. The Nb in Inconel 625 and 718 changed the way the Cr is depleted in these alloys. Grain-boundary engineering (GBE) of Incoloy 800H improved the corrosion resistance (weight loss and maximum depth of attack) by nearly 50% as compared to the as-received Incoloy 800H sample. A high temperature pump, thermal flow meter, and pressure differential device was designed, constructed and tested for use in the loop, The heat transfer of the molten chloride salt was found to follow general correlations used to estimate the Nusselt number for water in both the forced convection laminar regime and in the mixed convection regime.

Arsenic Remediation Enhancement Through Chemical Additions to Pump and Treat Operations

NASA Astrophysics Data System (ADS)

Wovkulich, K.; Mailloux, B. J.; Stute, M.; Simpson, H. J.; Keimowitz, A. R.; Powell, A.; Lacko, A.; Chillrud, S. N.

2008-12-01

Arsenic is a contaminant found at more than 500 US Superfund sites. Since pump and treat technologies are widely used for remediation of contaminated groundwater, increasing the efficiency of contaminant removal at such sites should allow limited financial resources to clean up more sites. The Vineland Chemical Company Superfund site is extensively contaminated with arsenic after waste arsenic salts were stored and disposed of improperly for much of the company's 44 year manufacturing lifetime. Despite approximately eight years of pump and treat remediation, arsenic concentrations in the recovery wells can still be greater than 1000 ppb. The arsenic concentrations in the groundwater remain high because of slow desorption of arsenic from contaminated aquifer solids. Extrapolation of laboratory column experiments suggest that continuing the current groundwater remediation practice based on flushing ambient groundwater through the system may require on the order of hundreds of years to clean the site. However, chemical additions of phosphate or oxalic acid into the aquifer could decrease the remediation time scale substantially. Laboratory results from a soil column experiment using input of 10 mM oxalic acid suggest that site clean up of groundwater could be decreased to as little as four years. Pilot scale forced gradient field experiments will help establish whether chemical additions can be effective for increasing arsenic mobilization from aquifer solids and thus substantially decrease pump and treat clean up time.

Tracing long-term vadose zone processes at the Nevada Test Site, USA

PubMed Central

Hunt, James R.; Tompson, Andrew F. B.

2010-01-01

The nuclear weapons testing programme of the USA has released radionuclides to the subsurface at the Nevada Test Site. One of these tests has been used to study the hydrological transport of radionuclides for over 25 years in groundwater and the deep unsaturated zone. Ten years after the weapon’s test, a 16 year groundwater pumping experiment was initiated to study the mobility of radionuclides from that test in an alluvial aquifer. The continuously pumped groundwater was released into an unlined ditch where some of the water infiltrated into the 200 m deep vadose zone. The pumped groundwater had well-characterized tritium activities that were utilized to trace water migration in the shallow and deep vadose zones. Within the near-surface vadose zone, tritium levels in the soil water are modelled by a simple one-dimensional, analytical wetting front model. In the case of the near-surface soils at the Cambric Ditch experimental site, water flow and salt accumulation appear to be dominated by rooted vegetation, a mechanism not included within the wetting front model. Simulation results from a two-dimensional vadose groundwater flow model illustrate the dominance of vertical flow in the vadose zone and the recharge of the aquifer with the pumped groundwater. The long-time series of hydrological data provides opportunities to understand contaminant transport processes better in the vadose zone with an appropriate level of modelling. PMID:21785525

Calculation of area and volume for the north part of Great Salt Lake, Utah

USGS Publications Warehouse

Baskin, Robert L.

2006-01-01

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands, collected bathymetric data for the north part of Great Salt Lake during the spring and early summer of 2006 using a single-beam, high-definition fathometer and real-time differential global positioning system. About 5.2 million depth measurements were collected along more than 765 miles (1,230 kilometers) of survey transects. Sound-velocity profiles were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed with commercial hydrographic software and exported into geographic information system (GIS) software for mapping and calculation of area and volume. Area and volume calculations show a maximum area of about 385,000 acres (1,560 square kilometers) and a maximum volume of about 5,693,000 acre-feet (about 7 cubic kilometers) at a water-surface altitude of 4,200 feet (1,280 meters). Minimum natural water-surface altitude of the north part of Great Salt Lake is just below 4,167 feet (1,270 meters) in the area just north of the Union Pacific railroad causeway halfway between Saline and the western edge of the lake. The north part of Great Salt Lake generally grades gradually to the west and north and is bounded by steep scarps along its eastern border. Calculations for area and volume are based on a low altitude of 4,167 feet (1,270 meters) to a high altitude of 4,200 feet (1,280 meters).

An In situ Study of Seasonal Dissolved Organic Carbon and Nutrient Fluxes from a Spartina alterniflora Salt Marsh in North Carolina

NASA Astrophysics Data System (ADS)

Detweiler, D. J.; Loh, A. N.

2016-02-01

Spartina alterniflora salt marshes are among the most productive and biogeochemically active ecosystems on Earth. While they have been shown to be sources of dissolved organic carbon (DOC) and nutrient export to the coastal ocean via tidal processes, it has not been well quantified experimentally. The purpose of this study was to quantify DOC and nutrient fluxes from a fringing S. alterniflora salt marsh in North Carolina. The experiment was conducted using in situ benthic microcosm chambers filled with seawater during a flooding tide; the chambers were then plugged, and samples were collected during an ebbing tide over the course of 270 minutes while simulating light and dark conditions. Water samples were filtered and analyzed for DOC and nutrient concentrations over time and used to calculate fluxes from vegetated (S. alterniflora) and non-vegetated marsh sediments. Preliminary daily flux calculations show that fluxes from vegetated sediments have a higher magnitude when compared to fluxes from non-vegetated sediments. Daily flux calculations also suggest that vegetated sediments act as a DOC source while non-vegetated sediments act as a DOC sink. Additional flux data for dissolved inorganic and organic nitrogen (DIN, DON) and dissolved inorganic and organic phosphorus (DIP, DOP) as well as marsh sediment characterization will also be presented. Ultimately, these data will provide seasonal daily flux calculations for S. alterniflora salt marshes and insight as to how changing environmental conditions such as wetland modification, wetland destruction, nutrient input, and climate change are affecting coastal biogeochemical cycles.

Structure of a prokaryotic virtual proton pump at 3.2 Å resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Yiling; Jayaram, Hariharan; Shane, Tania

2009-09-15

To reach the mammalian gut, enteric bacteria must pass through the stomach. Many such organisms survive exposure to the harsh gastric environment (pH 1.5-4) by mounting extreme acid-resistance responses, one of which, the arginine-dependent system of Escherichia coli, has been studied at levels of cellular physiology, molecular genetics and protein biochemistry. This multiprotein system keeps the cytoplasm above pH 5 during acid challenge by continually pumping protons out of the cell using the free energy of arginine decarboxylation. At the heart of the process is a 'virtual proton pump' in the inner membrane, called AdiC, that imports L-arginine from themore » gastric juice and exports its decarboxylation product agmatine. AdiC belongs to the APC superfamily of membrane proteins, which transports amino acids, polyamines and organic cations in a multitude of biological roles, including delivery of arginine for nitric oxide synthesis, facilitation of insulin release from pancreatic {beta}-cells, and, when inappropriately overexpressed, provisioning of certain fast-growing neoplastic cells with amino acids. High-resolution structures and detailed transport mechanisms of APC transporters are currently unknown. Here we describe a crystal structure of AdiC at 3.2 {angstrom} resolution. The protein is captured in an outward-open, substrate-free conformation with transmembrane architecture remarkably similar to that seen in four other families of apparently unrelated transport proteins.« less

Pump-probe imaging of nanosecond laser-induced bubbles in distilled water solutions: Observations of laser-produced-plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, R.; Camacho-Lopez, S.

2010-11-15

This article presents the analysis of the laser-produced-plasma (LPP) formed by the focusing of a 9 ns laser pulse, {lambda}=532 nm, with a NA=0.6 aspherical lens using energies between 100-1500 {mu}J, into distilled water with varying solutions of table salt. Observations of the filamentation plasma were made, which are explained by self-focusing of the laser pulse by the LPP through ponderomotive cavitation of the electron plasma in the center of the beam. The filamentation of the beam through a low density plasma wave guide explains why the transmission of the pump laser through the interaction region was notably higher onmore » previous experiments that we performed [R. Evans et al., Opt. Express 16, 7481 (2008)], than a very similar set of experiments performed by Noack and Vogel [IEEE J. Quantum Electron. 35, 1156 (1999)].« less

Inhibitors of bacterial multidrug efflux pumps potentiate antimicrobial photoinactivation.

PubMed

Tegos, George P; Masago, Kayo; Aziz, Fatima; Higginbotham, Andrew; Stermitz, Frank R; Hamblin, Michael R

2008-09-01

Antimicrobial photodynamic inactivation (APDI) combines a nontoxic photoactivatable dye or photosensitizer (PS) with harmless visible light to generate singlet oxygen and reactive oxygen species that kill microbial cells. Cationic phenothiazinium dyes, such as toluidine blue O (TBO), are the only PS used clinically for APDI, and we recently reported that this class of PS are substrates of multidrug efflux pumps in both gram-positive and gram-negative bacteria. We now report that APDI can be significantly potentiated by combining the PS with an efflux pump inhibitor (EPI). Killing of Staphylococcus aureus mediated by TBO and red light is greatly increased by coincubation with known inhibitors of the major facilitator pump (NorA): the diphenyl urea INF271, reserpine, 5'-methoxyhydnocarpin, and the polyacylated neohesperidoside, ADH7. The potentiation effect is greatest in the case of S. aureus mutants that overexpress NorA and least in NorA null cells. Addition of the EPI before TBO has a bigger effect than addition of the EPI after TBO. Cellular uptake of TBO is increased by EPI. EPI increased photodynamic inactivation killing mediated by other phenothiazinium dyes, such as methylene blue and dimethylmethylene blue, but not that mediated by nonphenothiazinium PS, such as Rose Bengal and benzoporphyrin derivative. Killing of Pseudomonas aeruginosa mediated by TBO and light was also potentiated by the resistance nodulation division pump (MexAB-OprM) inhibitor phenylalanine-arginine beta-naphthylamide but to a lesser extent than for S. aureus. These data suggest that EPI could be used in combination with phenothiazinium salts and light to enhance their antimicrobial effect against localized infections.

Assessing the groundwater salinization in closed hydrologic basins due to overdraft

NASA Astrophysics Data System (ADS)

Guo, Z.; Pauloo, R.; Fogg, G. E.

2016-12-01

Population growth and the expansion of agriculture, coupled with climate uncertainties, have accelerated groundwater pumping and overdraft in alluvial aquifers worldwide. In many agricultural basins, the low rate of replenishment is far exceeded by the rate of groundwater pumping in overdrafted aquifers, which results in the substantial water table declines and in effect contributes to the formation of a "closed" basin. In fact, even modest amounts of groundwater system drawdown that do not produce what is construed as overdraft, can result in most of the groundwater discharge occurring as evapotranspiration via irrigation practices, converting the basin to a closed groundwater basin. Moreover, in past decades, extreme weather conditions (i.e., severe drought in California for the past five years) have resulted in substantially reduced surface water storage. This increases demand for groundwater to supplement low surface water supplies, and consequently, drives groundwater overdraft, and hence, groundwater salinization. In these newly closed basins, just as in other naturally closed basins such as Death Valley and the Great Salt Lake, groundwater salinity must increase not only due to evaporation, but also due to rock water interactions in the groundwater system, and lack of a natural outlet for the groundwater. In this study, the water balance and salt balance in closed basins of the Central Valley, California are computed. Groundwater degradation under the current overdraft conditions is further investigated using simple models that are developed by upscaling more complex and heterogeneous transport models. The focus of this study is to determine the applicability of these simple models to represent regional transport without explicitly including the large-scale heterogeneity inherent in the more complex models. Groundwater salinization processes, including salt accumulation caused by evapotranspiration of applied irrigation water and rock-groundwater interactions are simulated, and the time scales under which groundwater salinity may pose a threat to societies is estimated. Lastly, and most importantly, management strategies to mitigate groundwater salinization are examined.

The effects of two different water management regimes on flooding and mosquito production in a salt marsh impoundment.

PubMed

Carlson, D B; Vigliano, R R

1985-06-01

Over two years, the management regimes of: 1) opening a southeast Florida salt marsh impoundment to the adjacent estuary with culverts through the dike, then, 2) passively retaining water with flapgate risers was studied to determine the effects on marsh flooding and resultant mosquito production. Larval dipping demonstrated that all broods occurred at elevations of 0.25-0.90 ft (= 0.08-0.27 m) NGVD. Mosquito production differed significantly between some sampling quadrats and 65 (out of 75) broods were produced in the spring and summer from rainfall. Without artificial pumping, trapping of rainfall with flapgate risers aided in eliminating oviposition sites but still allowed mosquito production in some marsh locations. Even though tidal flooding permitted larvivorous fish access to mosquito larvae, they were not able to provide adequate control to eliminate larviciding.

Changes in cellular distribution regulate SKD1 ATPase activity in response to a sudden increase in environmental salinity in halophyte ice plant

PubMed Central

Jou, Yingtzy; Chiang, Chih-Pin; Yen, Hungchen Emilie

2013-01-01

Halophyte Mesembryanthemum crystallinum L. (ice plant) rapidly responds to sudden increases in salinity in its environment by activating specific salt-tolerant mechanisms. One major strategy is to regulate a series of ion transporters and proton pumps to maintain cellular Na+/K+ homeostasis. Plant SKD1 (suppressor of K+ transport growth defect 1) proteins accumulate in cells actively engaged in the secretory processes, and play a critical role in intracellular protein trafficking. Ice plant SKD1 redistributes from the cytosol to the plasma membrane hours after salt stressed. In combination with present knowledge of this protein, we suggest that stress facilitates SKD1 movement to the plasma membrane where ADP/ATP exchange occurs, and functions in the regulation of membrane components such as ion transporters to avoid ion toxicity. PMID:24390077

Cascade Reverse Osmosis Air Conditioning System: Cascade Reverse Osmosis and the Absorption Osmosis Cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

BEETIT Project: Battelle is developing a new air conditioning system that uses a cascade reverse osmosis (RO)-based absorption cycle. Analyses show that this new cycle can be as much as 60% more efficient than vapor compression, which is used in 90% of air conditioners. Traditional vapor-compression systems use polluting liquids for a cooling effect. Absorption cycles use benign refrigerants such as water, which is absorbed in a salt solution and pumped as liquid—replacing compression of vapor. The refrigerant is subsequently separated from absorbing salt using heat for re-use in the cooling cycle. Battelle is replacing thermal separation of refrigerant withmore » a more efficient reverse osmosis process. Research has shown that the cycle is possible, but further investment will be needed to reduce the number of cascade reverse osmosis stages and therefore cost.« less

The application of hydrometeorological data obtained by remote sensing techniques for multipurpose reservoir operations. [Arizona

NASA Technical Reports Server (NTRS)

Warskow, W. L.; Wilson, T. T., Jr.; Kirdar, K.

1975-01-01

Watershed snowpack and streamflow data obtained and transmitted by (ERTS) satellite were used in the operational and water management decisions in the Salt River Project. Located in central Arizona, the Project provides water and electric power for the more than 1.1 million residents of the Salt River Valley. The water supply source is a 33,670 square kilometer (13,000 square mile) watershed and 250 deep well pumps. Six storage reservoirs, four of which have hydroelectric capability, located on two river systems have a storage capacity of over 246,600 hectare-meters (2,000,000 AF.). Information from the watershed during the normal runoff period of December to May and more especially during critical periods of high runoff and minimum reservoir storage capacity is necessary for the reservoir operation regimen. Extent of the snowpack, depth of snow, and the condition of the pack were observed in aerial flights over the watershed.

Case study of a sabkha sedimentary environment: Mallahat al Bariquah, Libya

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krason, J.

1987-05-01

The importance of the sabkha sedimentary environment for formation and/or accumulation of hydrocarbons, salts, and various metalliferous mineral deposits has been recognized by many geologists. A sabkha in which sedimentation and the formation of salt deposits and hydrocarbons is in progress is located along the Mediterranean Sea coast, in northwestern Libya and northeastern Tunisia. The sabkha Mallahat al Bariquah was drilled in a regular grid at 1-km spacing; 63 holes have been completed. The sabkha and its vicinity were geologically mapped (1:20,000). Several hundred core and loose rock samples were thoroughly examined with regard to the lithology, mineralogy, paleontology, andmore » chemical composition. The chemistry of brine from each drill hole and solar pan was determined. Three 24-hour pumping tests were performed, and the hydrogeological conditions of the sabkha were analyzed in detail. Economically valuable bedded salt reserves of 170,800,000 MT of NaCl were discovered and proven. Additionally, over 30 million MT of potassium, magnesium, and sodium salts including bromides are recoverable from the brine. Although marine-coastal sabkhas are common, the extensive scope of this study is unique. Mallahat al Bariquah sabkha is not unique with regard to its geographic, climatic, or sedimentary environments. Therefore, Mallahat al Bariquah can be considered as a model applicable in exploration for and study of similar sedimentary environments in other geographic regions and older geologic epochs.« less

Behaviour of conductivity improvers in jet fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dacre, B.; Hetherington, J.I.

1995-05-01

Dangerous accumulation of electrostatic charge can occur due to high speed pumping and microfiltration of fuel. This can be avoided by increasing the electrical conductivity of the fuel using conductivity improver additives. However, marked variations occur in the conductivity response of different fuels when doped to the same level with conductivity improver. This has been attributed to interactions of the conductivity improver with other fuel additives or fuel contaminants. The present work concentrates on the effects of fuel contaminants, in particular polar compounds, on the performance of the conductivity improver. Conductivity is the fuel property of prime interest. The conductivitymore » response of model systems of the conductivity improver STADIS 450 in dodecane has been measured and the effect on this conductivity of additions of model polar contaminants sodium naphthenate, sodium dodecyl benzene sulphonate, and sodium phenate have been measured. The sodium salts have been found to have a complex effect on the performance of STADIS 450, reducing the conductivity at low concentrations to a minimum value and then increasing the conductivity at high concentrations of sodium salts. This work has focused on characterising this minimum in the conductivity values and on understanding the reason for its occurrence. The effects on the minimum conductivity value of the following parameters are investigated: (a) time, (b) STADIS 450 concentration, (c) sodium salt concentration, (d) mixed sodium salts, (e) experimental method, (f) a phenol, (g) individual components of STADIS 450. The complex conductivity response of the STADIS 450 to sodium salt impurities is discussed in terms of possible inter-molecular interactions.« less

Earth Observations taken by the Expedition 22 Crew

NASA Image and Video Library

2009-12-15

ISS022-E-012224 (15 Dec. 2009) --- Evaporation ponds in the Salar de Atacama, Chile are featured in this image photographed by an Expedition 22 crew member on the International Space Station. The Salar (salt flat) de Atacama in Chile is an enclosed basin with no drainage outlets. While the grey-brown surface of the Salar is flat and desiccated, mineral-rich brines - water with a high percentage of dissolved salts - are located below the surface. The subsurface brines of the Salar de Atacama are particularly rich in lithium salts. Lithium is an essential component of advanced batteries and medicines, among many other uses. The brines are pumped to the surface through a network of wells and into large shallow evaporation ponds ? three such evaporation pond facilities are visible in the center of the image. Color variations in the ponds are due to varying amounts of salts relative to water. The dry and windy climate enhances evaporation of the water, leaving concentrated salts behind for extraction of the lithium. The Salar de Atacama is located in the southern half of the Atacama Desert ? with no historical or current records of rainfall in some parts of this desert, it is considered to be one of the driest places on Earth. This photograph illustrates the central portion of the Salar de Atacama. It is bounded by brown to grey-brown folded and faulted strata of the Cordillera de la Sal to the northwest (upper left) and darker bedrock of the Cordon de Lila to the south (lower right).

Core Design Characteristics of the Fluoride Salt-Cooled High Temperature Demonstration Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Nicholas R; Qualls, A L; Betzler, Benjamin R

2016-01-01

Fluoride salt-cooled high temperature reactors (FHRs) are a promising reactor technology option with significant knowledge gaps to implementation. One potential approach to address those technology gaps is via a small-scale demonstration reactor with the goal of increasing the technology readiness level (TRL) of the overall system for the longer term. The objective of this paper is to outline a notional concept for such a system, and to address how the proposed concept would advance the TRL of FHR concepts. Development of the proposed FHR Demonstration Reactor (DR) will enable commercial FHR deployment through disruptive and rapid technology development and demonstration.more » The FHR DR will close remaining gaps to commercial viability. Lower risk technologies are included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. Important capabilities that will be demonstrated by building and operating the FHR DR include core design methodologies; fabrication and operation of high temperature reactors; salt procurement, handling, maintenance, and ultimate disposal; salt chemistry control to maximize vessel life; tritium management; heat exchanger performance; pump performance; and reactivity control. The FHR DR is considered part of a broader set of FHR technology development and demonstration efforts, some of which are already underway. Nonreactor test efforts (e.g., heated salt loops or loops using simulant fluids) can demonstrate many technologies necessary for commercial deployment of FHRs. The FHR DR, however, fulfills a crucial role in FHR technology development by advancing the technical maturity and readiness level of the system as a whole.« less

Portable Intravenous Fluid Production Device For Ground Use Project

NASA Technical Reports Server (NTRS)

Oliva-Buisson, Yvette J.

2014-01-01

Several medical conditions require the administration of intravenous (IV) fluids,but limitations of mass, volume, shelf-life, transportation, and local resources can restrict the availability of these important fluids. Such limitations are expected in long-duration space exploration missions and in remote or austere places on Earth. This design uses regular drinking water that is pumped through two filters to produce, in minutes, sterile, ultrapure water that meets the stringent quality standards of the United States Pharmacopeia for Water for Injection (Total Bacteria, Conductivity, Endo - toxins, Total Organic Carbon). The device weighs 2.2 lb (1 kg) and is 10 in. long, 5 in. wide, and 3 in. high (˜25, 13, and 7.5 cm, respectively) in its storage configuration. This handheld device produces one liter of medical-grade water in 21 minutes. Total production capacity for this innovation is expected to be in the hundreds of liters. The device contains one battery powered electric mini-pump. Alternatively, a manually powered pump can be attached and used. Drinking water enters the device from a source water bag, flows through two filters, and final sterile production water exits into a sealed, medical-grade collection bag. The collection bag contains pre-placed crystalline salts to mix with product water to form isotonic intravenous medical solutions. Alternatively, a hypertonic salt solution can be injected into a filled bag. The filled collection bag is detached from the device and is ready for use or storage. This device currently contains one collection bag, but a manifold of several pre-attached bags or replacement of single collection bags under sterile needle technique is possible for the production of multiple liters. The entire system will be flushed, sealed, and radiation-sterilized. Operation of the device is easy and requires minimal training. Drinking water is placed into the collection bag. Inline stopcock flow valves at the source and collection bags are opened, and the mini-pump is turned on by a switch to begin fluid flow. When the collection bag is completely filled with the medical- grade water, the pump can be turned off. The pump is designed so it cannot pump air, and overfilling of the collection bag with fluid is avoided by placing an equal amount of water in the source bag. Backflow is avoided by inline check valves. The filled collection bag is disconnected from its tubing and is ready for use. The source bag can be refilled for production of multiple liters, or the source bag can be replaced with an input tube that can be placed in a larger potable water source if the device is attended. The device functions in all orientations independent of any gravity fields. In addition to creating IV fluids, the device produces medical-grade water, which can be used for mixing with medications for injection, reconstituting freeze-dried blood products for injection, or for wound hydration or irrigation. Potential worldwide use is expected with medical activities in environments that have limited resources, storage, or resupply such as in military field operations, humanitarian relief efforts, submarines, commercial cruise ships, etc.

APPLICATION OF VACUUM SALT DISTILLATION TECHNOLOGY FOR THE REMOVAL OF FLUORIDE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R.; Pak, D.

2011-08-10

Vacuum distillation of chloride salts from plutonium oxide (PuO{sub 2}) and simulant PuO{sub 2} has been previously demonstrated at Department of Energy (DOE) sites using kilogram quantities of chloride salt. The apparatus for vacuum distillation contains a zone heated using a furnace and a zone actively cooled using either recirculated water or compressed air. During a vacuum distillation operation, a sample boat containing the feed material is placed into the apparatus while it is cool, and the system is sealed. The system is evacuated using a vacuum pump. Once a sufficient vacuum is attained, heating begins. Volatile salts distill frommore » the heated zone to the cooled zone where they condense, leaving behind the non-volatile materials in the feed boat. The application of vacuum salt distillation (VSD) is of interest to the HB-Line Facility and the MOX Fuel Fabrication Facility (MFFF) at the Savannah River Site (SRS). Both facilities are involved in efforts to disposition excess fissile materials. Many of these materials contain chloride and fluoride salt concentrations which make them unsuitable for dissolution without prior removal of the chloride and fluoride salts. Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and HB-Line designed, developed, tested, and successfully deployed a system for the distillation of chloride salts. Subsequent efforts are attempting to adapt the technology for the removal of fluoride. Fluoride salts of interest are less-volatile than the corresponding chloride salts. Consequently, an alternate approach is required for the removal of fluoride without significantly increasing the operating temperature. HB-Line Engineering requested SRNL to evaluate and demonstrate the feasibility of an alternate approach using both non-radioactive simulants and plutonium-bearing materials. Whereas the earlier developments targeted the removal of sodium chloride (NaCl) and potassium chloride (KCl), the current activities are concerned with the removal of the halide ions associated with plutonium trifluoride (PuF{sub 3}), plutonium tetrafluoride (PuF{sub 4}), calcium fluoride (CaF{sub 2}), and calcium chloride (CaCl{sub 2}). This report discusses non-radioactive testing of small-scale and pilot-scale systems and radioactive testing of a small-scale system. Experiments focused on demonstrating the chemistry for halide removal and addressing the primary engineering questions associated with a change in the process chemistry.« less

Climate change impacts on net primary production (NPP) and export production (EP) regulated by increasing stratification and phytoplankton community structure in the CMIP5 models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Weiwei; Randerson, James T.; Moore, J. Keith

We examine climate change impacts on net primary production (NPP) and export production (sinking particulate flux; EP) with simulations from nine Earth system models (ESMs) performed in the framework of the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Global NPP and EP are reduced by the end of the century for the intense warming scenario of Representative Concentration Pathway (RCP) 8.5. Relative to the 1990s, NPP in the 2090s is reduced by 2–16% and EP by 7–18%. The models with the largest increases in stratification (and largest relative declines in NPP and EP) also show the largest positivemore » biases in stratification for the contemporary period, suggesting overestimation of climate change impacts on NPP and EP. All of the CMIP5 models show an increase in stratification in response to surface–ocean warming and freshening, which is accompanied by decreases in surface nutrients, NPP and EP. There is considerable variability across the models in the magnitudes of NPP, EP, surface nutrient concentrations and their perturbations by climate change. The negative response of NPP and EP to increasing stratification reflects primarily a bottom-up control, as upward nutrient flux declines at the global scale. Models with dynamic phytoplankton community structure show larger declines in EP than in NPP. This pattern is driven by phytoplankton community composition shifts, with reductions in productivity by large phytoplankton as smaller phytoplankton (which export less efficiently) are favored under the increasing nutrient stress. Thus, the projections of the NPP response to climate change are critically dependent on the simulated phytoplankton community structure, the efficiency of the biological pump and the resulting levels of regenerated production, which vary widely across the models. In conclusion, community structure is represented simply in the CMIP5 models, and should be expanded to better capture the spatial patterns and climate-driven changes in export efficiency.« less

Climate change impacts on net primary production (NPP) and export production (EP) regulated by increasing stratification and phytoplankton community structure in the CMIP5 models

DOE PAGES

Fu, Weiwei; Randerson, James T.; Moore, J. Keith

2016-09-16

We examine climate change impacts on net primary production (NPP) and export production (sinking particulate flux; EP) with simulations from nine Earth system models (ESMs) performed in the framework of the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Global NPP and EP are reduced by the end of the century for the intense warming scenario of Representative Concentration Pathway (RCP) 8.5. Relative to the 1990s, NPP in the 2090s is reduced by 2–16% and EP by 7–18%. The models with the largest increases in stratification (and largest relative declines in NPP and EP) also show the largest positivemore » biases in stratification for the contemporary period, suggesting overestimation of climate change impacts on NPP and EP. All of the CMIP5 models show an increase in stratification in response to surface–ocean warming and freshening, which is accompanied by decreases in surface nutrients, NPP and EP. There is considerable variability across the models in the magnitudes of NPP, EP, surface nutrient concentrations and their perturbations by climate change. The negative response of NPP and EP to increasing stratification reflects primarily a bottom-up control, as upward nutrient flux declines at the global scale. Models with dynamic phytoplankton community structure show larger declines in EP than in NPP. This pattern is driven by phytoplankton community composition shifts, with reductions in productivity by large phytoplankton as smaller phytoplankton (which export less efficiently) are favored under the increasing nutrient stress. Thus, the projections of the NPP response to climate change are critically dependent on the simulated phytoplankton community structure, the efficiency of the biological pump and the resulting levels of regenerated production, which vary widely across the models. In conclusion, community structure is represented simply in the CMIP5 models, and should be expanded to better capture the spatial patterns and climate-driven changes in export efficiency.« less

A linkage between Asian dust, dissolved iron and marine export production in the deep ocean

NASA Astrophysics Data System (ADS)

Han, Yongxiang; Zhao, Tianliang; Song, Lianchun; Fang, Xiaomin; Yin, Yan; Deng, Zuqin; Wang, Suping; Fan, Shuxian

2011-08-01

Iron-addition experiments have revealed that iron supply exerts controls on biogeochemical cycles in the ocean and ultimately influences the Earth's climate system. The iron hypothesis in its broad outlines has been proved to be correct. However, the hypothesis needs to be verified with an observable biological response to specific dust deposition events. Plankton growth following the Asian dust storm over Ocean Station PAPA (50°N, 145°W) in the North Pacific Ocean in April 2001 was the first supportive evidence of natural aeolian iron inputs to ocean; The data were obtained through the SeaWiFS satellite and robot carbon explorers by Bishop et al. Using the NARCM modeling results in this study, the calculated total dust deposition flux was 35 mg m -2 per day in PAPA region from the dust storm of 11-13 April, 2001 into 0.0615 mg m -2 d -1 (about 1100 nM) soluble iron in the surface layer at Station PAPA. It was enough for about 1100 nM to enhance the efficiency of the marine biological pump and trigger the rapid increase of POC and chlorophyll. The iron fertilization hypothesis therefore is plausible. However, even if this specific dust event can support the iron fertilization hypothesis, long-term observation data are lacking in marine export production and continental dust. In this paper, we also conducted a simple correlation analysis between the diatoms and foraminifera at about 3000 m and 4000 m at two subarctic Pacific stations and the dust aerosol production from China's mainland. The correlation coefficient between marine export production and dust storm frequency in the core area of the dust storms was significantly high, suggesting that aerosols generated by Asian dust storm are the source of iron for organic matter fixation in the North Pacific Ocean. These results suggest that there could be an interlocking chain for the change of atmospheric dust aerosol-soluble iron-marine export production.

The glacial iron cycle from source to export

NASA Astrophysics Data System (ADS)

Hawkings, J.; Wadham, J. L.; Tranter, M.; Raiswell, R.; Benning, L. G.; Statham, P. J.; Tedstone, A. J.; Nienow, P. W.; Telling, J.; Bagshaw, E.; Simmons, S. L.

2014-12-01

Nutrient availability limits primary production in large sectors of the world's oceans. Iron is the major limiting nutrient in around one third of the oceanic euphotic zone, most significantly in the Southern Ocean proximal to Antarctica. In these areas the availability of bioavailable iron can influence the amount of primary production, and thus the strength of the biological pump and associated carbon drawdown from the atmosphere. Despite experiencing widespread iron limitation, the Polar oceans are among the most productive on Earth. Due to the extreme cold, remoteness and their perceived "stasis", ice sheets have previously been though of as insignificant in global biogeochemical cycles. However, large marine algal blooms have been observed in iron-limited areas where glacial influence is large, and it is possible that these areas are stimulated by glacial bioavailable iron input. Here we discuss the importance of the Greenland and Antarctic ice sheets in the global iron cycle. Using field collected trace element data, bulk meltwater chemistry and mineralogical analysis, including photomicrographs, EELS and XANES, we present, for the first time, a conceptual model of the glacial iron cycle from source to export. Using this data we discuss the sources of iron in glacial meltwater, transportation and alteration through the glacial system, and subsequent export to downstream environments. Data collected in 2012 and 2013 from two different Greenlandic glacial catchments are shown, with the most detailed breakdown of iron speciation and concentrations in glacial areas yet reported. Furthermore, the first data from Greenlandic icebergs is presented, allowing meltwater-derived and iceberg-derived iron export to be compared, and the influence of both in marine productivity to be estimated. Using our conceptual model and flux estimates from our dataset, glacial iron delivery in both the northern and southern hemisphere is discussed. Finally, we compare our flux estimates to other major iron sources to the polar regions such as aeolian dust, and discuss potential implications of increased melting of the ice sheets on the global iron cycle in the future.

Predictable and efficient carbon sequestration in the North Pacific Ocean supported by symbiotic nitrogen fixation

PubMed Central

Karl, David M.; Church, Matthew J.; Dore, John E.; Letelier, Ricardo M.; Mahaffey, Claire

2012-01-01

The atmospheric and deep sea reservoirs of carbon dioxide are linked via physical, chemical, and biological processes. The last of these include photosynthesis, particle settling, and organic matter remineralization, and are collectively termed the “biological carbon pump.” Herein, we present results from a 13-y (1992–2004) sediment trap experiment conducted in the permanently oligotrophic North Pacific Subtropical Gyre that document a large, rapid, and predictable summertime (July 15–August 15) pulse in particulate matter export to the deep sea (4,000 m). Peak daily fluxes of particulate matter during the summer export pulse (SEP) average 408, 283, 24.1, 1.1, and 67.5 μmol·m−2·d−1 for total carbon, organic carbon, nitrogen, phosphorus (PP), and biogenic silica, respectively. The SEP is approximately threefold greater than mean wintertime particle fluxes and fuels more efficient carbon sequestration because of low remineralization during downward transit that leads to elevated total carbon/PP and organic carbon/PP particle stoichiometry (371:1 and 250:1, respectively). Our long-term observations suggest that seasonal changes in the microbial assemblage, namely, summertime increases in the biomass and productivity of symbiotic nitrogen-fixing cyanobacteria in association with diatoms, are the main cause of the prominent SEP. The recurrent SEP is enigmatic because it is focused in time despite the absence of any obvious predictable stimulus or habitat condition. We hypothesize that changes in day length (photoperiodism) may be an important environmental cue to initiate aggregation and subsequent export of organic matter to the deep sea. PMID:22308450

Predictable and efficient carbon sequestration in the North Pacific Ocean supported by symbiotic nitrogen fixation.

PubMed

Karl, David M; Church, Matthew J; Dore, John E; Letelier, Ricardo M; Mahaffey, Claire

2012-02-07

The atmospheric and deep sea reservoirs of carbon dioxide are linked via physical, chemical, and biological processes. The last of these include photosynthesis, particle settling, and organic matter remineralization, and are collectively termed the "biological carbon pump." Herein, we present results from a 13-y (1992-2004) sediment trap experiment conducted in the permanently oligotrophic North Pacific Subtropical Gyre that document a large, rapid, and predictable summertime (July 15-August 15) pulse in particulate matter export to the deep sea (4,000 m). Peak daily fluxes of particulate matter during the summer export pulse (SEP) average 408, 283, 24.1, 1.1, and 67.5 μmol·m(-2)·d(-1) for total carbon, organic carbon, nitrogen, phosphorus (PP), and biogenic silica, respectively. The SEP is approximately threefold greater than mean wintertime particle fluxes and fuels more efficient carbon sequestration because of low remineralization during downward transit that leads to elevated total carbon/PP and organic carbon/PP particle stoichiometry (371:1 and 250:1, respectively). Our long-term observations suggest that seasonal changes in the microbial assemblage, namely, summertime increases in the biomass and productivity of symbiotic nitrogen-fixing cyanobacteria in association with diatoms, are the main cause of the prominent SEP. The recurrent SEP is enigmatic because it is focused in time despite the absence of any obvious predictable stimulus or habitat condition. We hypothesize that changes in day length (photoperiodism) may be an important environmental cue to initiate aggregation and subsequent export of organic matter to the deep sea.

Geology and ground-water resources of Galveston County, Texas

USGS Publications Warehouse

Petitt, Ben McDowell; Winslow, Allen George

1957-01-01

Much additional ground water could be obtained from both the "Alta Loma" sand and the upper part of the Beaumont clay, especially in the northern and western parts of the county. Before large developments of supplies are planned, however, these areas should be explored by test drilling. The problems of well spacing and pumping rates should be thoroughly studied in order to determine the maximum development permitted by the ground-water supply. Current observations should be continued with special emphasis on the progress of salt-water encroachment.

Simple practical approach for sample loading prior to DNA extraction using a silica monolith in a microfluidic device.

PubMed

Shaw, Kirsty J; Joyce, Domino A; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

2009-12-07

A novel DNA loading methodology is presented for performing DNA extraction on a microfluidic system. DNA in a chaotropic salt solution was manually loaded onto a silica monolith orthogonal to the subsequent flow of wash and elution solutions. DNA was successfully extracted from buccal swabs using electro-osmotic pumping (EOP) coupled with in situ reagents contained within a 1.5% agarose gel matrix. The extracted DNA was of sufficient quantity and purity for polymerase chain reaction (PCR) amplification.

IV-VI compound midinfrared high-reflectivity mirrors and vertical-cavity surface-emitting lasers grown by molecular-beam epitaxy

NASA Astrophysics Data System (ADS)

Shi, Z.; Xu, G.; McCann, P. J.; Fang, X. M.; Dai, N.; Felix, C. L.; Bewley, W. W.; Vurgaftman, I.; Meyer, J. R.

2000-06-01

Midinfrared broadband high-reflectivity Pb1-xSrxSe/BaF2 distributed Bragg reflectors and vertical-cavity surface-emitting lasers (VCSELs) with PbSe as the active material were grown by molecular-beam epitaxy. Because of an extremely high index contrast, mirrors with only three quarter-wave layer pairs had reflectivities exceeding 99%. For pulsed optical pumping, a lead salt VCSEL emitting at the cavity wavelength of 4.5-4.6 μm operated nearly to room temperature (289 K).

Post-Explosion Tracer Gas Study in Fractured Granite

NASA Astrophysics Data System (ADS)

Avendano, S.; Horne, M.; Herrera, C.; Person, M. A.; Gorman, E.; Stroujkova, A. F.; Gomez-Velez, J. D.

2017-12-01

Radioactive noble gas detection at suspected underground nuclear test sites is the only proven way to confirm that a nuclear test has occurred. However, the migration of gas effluent through fracture networks is still poorly understood. A pilot field study of the gas migration through rock damaged by explosions was conducted in a rock quarry in New Hampshire in the summer of 2017. Tracer gas (SF6), used as a proxy for the noble gas, was released into a cavity created by an explosion (63 kg of TNT at a depth of 13 m) conducted during the summer of 2016. The upper 5 m of borehole were grouted with stainless steel tubing sealed in the concrete and the gas was pumped through the tubing. Before the gas release, we conducted a series of geophysical and hydrologic tests: a pump test, several slug tests, a salt tracer release in two boreholes, and TEM and ERT surveys. Pressure and electrical conductivity transducers were placed in the surrounding boreholes to monitor the pressure changes and tracer arrival during the pumping. The results of the pump test show that the rock is well connected and has high permeability. Interestingly, the injection of gas resulted in a substantial increase of the local hydraulic conductivity, as evidenced by slug test results before and after injection. The pressure changes in the surrounding boreholes were also monitored during the gas release. We observed gas breakthrough immediately after the release. During the first minute after injection, a pressure wave was observed in two boreholes suggestive of inertial effects and hydraulic fracturing after gas release. The concentrations observed at each monitoring site are consistent with the pump testing. The results of this study will be used in our upcoming experiments and to test detailed mathematical models.

Understanding the recent changes in the Southern Ocean carbon cycle: A multidisciplinary approach

NASA Astrophysics Data System (ADS)

Manizza, M.; Kahru, M.; Menemenlis, D.; Nevison, C. D.; Mitchell, B. G.; Keeling, R. F.

2016-12-01

The Southern Ocean represents a key area of the global ocean for the uptake of the CO2 originating from fossil fuels emissions. In these waters, cold temperatures combined with high rates of biological production drive the carbon uptake that accounts for about one-third of the global ocean uptake.Recent studies showed that changes in the Southern Annular Mode (SAM) index, mainly a proxy of the intensity of westerly winds, had a significant impact on the temporal variability of the CO2 uptake in the Southern Ocean. In order to shed light on this problem we propose to use both satellite-derived estimates of ocean productivity and carbon export in combinations of ocean physical and biogeochemical state estimates focusing on the 2006-2013 period. While the estimates of carbon fixation and export based on remote sensing will provide key information on the spatial and temporal variations of the biological carbon pump, the ocean state estimates will provide additional information on physical and carbon cycle processes, including the air-sea CO2 fluxes of the Southern Ocean in the 2006-2013 period where model solutions have been optimized.These physical estimates will be used to force an ocean biogeochemical model (ECCO2-Darwin) that will compute the CO2 uptake for each year. The physical model, forced with optimized atmospheric forcing, aims to realistically simulate interannual ocean climate variability that drives changes in both physical and biogeochemical processes ultimately impacting the carbon uptake of the Southern Ocean, and potentially responding to the SAM index variations.Although in this study great emphasis is given to the role of physical climate variations at driving the CO2 uptake of these polar waters, we will integrate model results with estimates from remote sensing techniques to better understand role of the biological carbon pump and its variability potentially responding to the SAM index changes.

Energy landscape of the reactions governing the Na+ deeply occluded state of the Na+/K+-ATPase in the giant axon of the Humboldt squid

PubMed Central

Castillo, Juan P.; De Giorgis, Daniela; Basilio, Daniel; Gadsby, David C.; Rosenthal, Joshua J. C.; Latorre, Ramon; Holmgren, Miguel; Bezanilla, Francisco

2011-01-01

The Na+/K+ pump is a nearly ubiquitous membrane protein in animal cells that uses the free energy of ATP hydrolysis to alternatively export 3Na+ from the cell and import 2K+ per cycle. This exchange of ions produces a steady-state outwardly directed current, which is proportional in magnitude to the turnover rate. Under certain ionic conditions, a sudden voltage jump generates temporally distinct transient currents mediated by the Na+/K+ pump that represent the kinetics of extracellular Na+ binding/release and Na+ occlusion/deocclusion transitions. For many years, these events have escaped a proper thermodynamic treatment due to the relatively small electrical signal. Here, taking the advantages offered by the large diameter of the axons from the squid Dosidicus gigas, we have been able to separate the kinetic components of the transient currents in an extended temperature range and thus characterize the energetic landscape of the pump cycle and those transitions associated with the extracellular release of the first Na+ from the deeply occluded state. Occlusion/deocclusion transition involves large changes in enthalpy and entropy as the ion is exposed to the external milieu for release. Binding/unbinding is substantially less costly, yet larger than predicted for the energetic cost of an ion diffusing through a permeation pathway, which suggests that ion binding/unbinding must involve amino acid side-chain rearrangements at the site. PMID:22143771

Energy landscape of the reactions governing the Na+ deeply occluded state of the Na+/K+-ATPase in the giant axon of the Humboldt squid.

PubMed

Castillo, Juan P; De Giorgis, Daniela; Basilio, Daniel; Gadsby, David C; Rosenthal, Joshua J C; Latorre, Ramon; Holmgren, Miguel; Bezanilla, Francisco

2011-12-20

The Na(+)/K(+) pump is a nearly ubiquitous membrane protein in animal cells that uses the free energy of ATP hydrolysis to alternatively export 3Na(+) from the cell and import 2K(+) per cycle. This exchange of ions produces a steady-state outwardly directed current, which is proportional in magnitude to the turnover rate. Under certain ionic conditions, a sudden voltage jump generates temporally distinct transient currents mediated by the Na(+)/K(+) pump that represent the kinetics of extracellular Na(+) binding/release and Na(+) occlusion/deocclusion transitions. For many years, these events have escaped a proper thermodynamic treatment due to the relatively small electrical signal. Here, taking the advantages offered by the large diameter of the axons from the squid Dosidicus gigas, we have been able to separate the kinetic components of the transient currents in an extended temperature range and thus characterize the energetic landscape of the pump cycle and those transitions associated with the extracellular release of the first Na(+) from the deeply occluded state. Occlusion/deocclusion transition involves large changes in enthalpy and entropy as the ion is exposed to the external milieu for release. Binding/unbinding is substantially less costly, yet larger than predicted for the energetic cost of an ion diffusing through a permeation pathway, which suggests that ion binding/unbinding must involve amino acid side-chain rearrangements at the site.

Regulation of cation transport in Saccharomyces cerevisiae by the salt tolerance gene HAL3.

PubMed Central

Ferrando, A; Kron, S J; Rios, G; Fink, G R; Serrano, R

1995-01-01

Dynamic regulation of ion transport is essential for homeostasis as cells confront changes in their environment. The gene HAL3 encodes a novel component of this regulatory circuit in the yeast Saccharomyces cerevisiae. Overexpression of HAL3 improves growth of wild-type cells exposed to toxic concentrations of sodium and lithium and suppresses the salt sensitivity conferred by mutation of the calcium-dependent protein phosphatase calcineurin. Null mutants of HAL3 display salt sensitivity. The sequence of HAL3 gives little clue to its function. However, alterations in intracellular cation concentrations associated with changes in HAL3 expression suggest that HAL3 activity may directly increase cytoplasmic K+ and decrease Na+ and Li+. Cation efflux in S. cerevisiae is mediated by the P-type ATPase encoded by the ENA1/PMR24 gene, a putative plasma membrane Na+ pump whose expression is salt induced. Acting in concert with calcineurin, HAL3 is necessary for full activation of ENA1 expression. This functional complementarity is also reflected in the participation of both proteins in recovery from alpha-factor-induced growth arrest. Recently, HAL3 was isolated as a gene (named SIS2) which when overexpressed partially relieves loss of transcription of G1 cyclins in mutants lacking the protein phosphatase Sit4p. Therefore, HAL3 influences cell cycle control and ion homeostasis, acting in parallel to the protein phosphatases Sit4p and calcineurin. PMID:7565698

Prenatal exposure to angiotensin II increases blood pressure and decreases salt sensitivity in rats.

PubMed

Svitok, Pavel; Senko, Tomas; Panakova, Zuzana; Olexova, Lucia; Krskova, Lucia; Okuliarova, Monika; Zeman, Michal

2017-01-01

Renin angiotensin aldosterone system (RAAS) plays an essential role in the homeostatic control of arterial blood pressure, perfusion of tissues, and control of extracellular fluid. Its components are highly expressed in the developing kidney, general vasculature, brain, and heart. A modified intrauterine environment alters mechanisms controlling blood pressure (BP) and can lead to hypertension in the adult offspring and developmentally programmed RAAS can be involved in this process. There are very little data about the effects of increased angiotensin II (Ang II) concentrations during pregnancy on in utero development of the fetus. In our study, we administered Ang II to pregnant female rats via osmotic mini-pumps and evaluated the postnatal development and BP control in the offspring. To estimate possible developmental changes in sensitivity to salt, we exposed the offspring to a diet with increased salt content and measured plasma aldosterone levels and plasma renin activity. Increased Ang II during pregnancy raised BP in the offspring; however, salt sensitivity was decreased in comparison to controls. Relative weight of the left ventricle was decreased in the offspring prenatally exposed to Ang II, while relative kidney weight was reduced only in female offspring. Prenatal treatment led to increased aldosterone levels and decreased plasma renin activity, suggesting a complex physiological response. Our results suggest that conditions leading to upregulation of RAAS during pregnancy can influence the cardiovascular system of the fetus and have a long-term impact on the offspring's health.

In Vitro Drug-Induced Liver Injury Prediction: Criteria Optimization of Efflux Transporter IC50 and Physicochemical Properties.

PubMed

Yucha, Robert W; He, Kan; Shi, Qin; Cai, Lining; Nakashita, Yukie; Xia, Cindy Q; Liao, Mingxiang

2017-06-01

Drug-induced liver injury (DILI) is a severe drug adverse response, which cannot always be reliably predicted in preclinical or clinical studies. Lack of observation of DILI during preclinical and clinical drug development has led to DILI being a leading cause of drug withdrawal from the market. As DILI is potentially fatal, pharmaceutical companies have been developing in vitro tools to screen for potential liver injury. Screens for physicochemical properties, mitochondrial function, and transport protein inhibition have all been employed to varying degrees of success. In vitro inhibition of the bile salt export pump (BSEP) has become a major risk factor for in vivo DILI predictions, yet discrepancies exist in which methods to use and the extent to which BSEP inhibition predicts clinical DILI. The presented work focuses on optimizing DILI predictions by comparing BSEP inhibition via the membrane vesicle assay and the hepatocyte-based BSEPcyte assay, as well as dual and triple liabilities. BSEP transport inhibition of taurcholic acids and glycocholic acids were similar for up to 29 drugs tested, in both the vesicle and hepatocyte-based assays. Positive and negative DILI predictions were optimized at a 50-µM cutoff value for 50 drugs using both NIH Livertox and PharmaPendium databases. Additionally, dual inhibition of BSEP and other efflux transporters (multidrug resistance-associated protein [MRP]2, MRP3, or MRP4) provided no observable predictive benefit compared with BSEP inhibition alone. Eighty-five percent of drugs with high molecular weight (>600 Da), high cLogP (>3), or a daily dose >100 mg and BSEP inhibition were associated with DILI. Triple liability of BSEP inhibition, high molecular weight, and high cLogP attained a 100% positive prediction rate. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Differential inhibition of rat and human Na+-dependent taurocholate cotransporting polypeptide (NTCP/SLC10A1)by bosentan: a mechanism for species differences in hepatotoxicity.

PubMed

Leslie, Elaine M; Watkins, Paul B; Kim, Richard B; Brouwer, Kim L R

2007-06-01

Bile acid accumulation in hepatocytes due to inhibition of the canalicular bile salt export pump (BSEP/ABCB11) has been proposed as a mechanism for bosentan-induced hepatotoxicity. The observation that bosentan does not induce hepatotoxicity in rats, although bosentan has been reported to inhibit rat Bsep and cause elevated serum bile acids, challenges this mechanism. The lack of hepatotoxicity could be explained if bosentan inhibited hepatocyte uptake as well as canalicular efflux of bile acids. In the current study, bosentan was found to be a more potent inhibitor of Na(+)-dependent taurocholate uptake in rat (IC(50) 5.4 microM) than human (IC(50) 30 microM) suspended hepatocytes. In addition, bosentan was a more potent inhibitor of taurocholate uptake by rat Na(+)-dependent taurocholate co-transporting polypeptide (Ntcp/Slc10a1) (IC(50) 0.71 microM) than human NTCP (SLC10A1) (IC(50) 24 microM) expressed in HEK293 cells. Thus, bosentan is a more potent inhibitor of Ntcp than NTCP, and this should result in less intrahepatocyte accumulation of bile acids in rats during bosentan treatment. To begin characterization of this species difference, two chimeric molecules were generated and expressed in HEK293 cells; NTCP(1-140)/Ntcp(141-362) and Ntcp(1-140)/NTCP(141-349). The mode of bosentan inhibition was noncompetitive for Ntcp, and competitive for NTCP (K(i) 18 microM) and NTCP(1-140)/Ntcp(141-362) (K(i) 1.7 microM); bosentan affected both the K(m) and V(max) of Ntcp(1-140)/NTCP(141-349) (K(i) 7.0 microM). The carboxyl portions of NTCP and Ntcp were found to confer species differences in basal taurocholate transport V(max). In conclusion, differential inhibition of Ntcp and NTCP may represent a novel mechanism for species differences in bosentan-induced hepatotoxicity.

Transporter Expression in Liver Tissue from Subjects with Alcoholic or Hepatitis C Cirrhosis Quantified by Targeted Quantitative Proteomics

PubMed Central

Wang, Li; Collins, Carol; Kelly, Edward J.; Chu, Xiaoyan; Ray, Adrian S.; Salphati, Laurent; Xiao, Guangqing; Lee, Caroline; Lai, Yurong; Liao, Mingxiang; Mathias, Anita; Evers, Raymond; Humphreys, William; Hop, Cornelis E. C. A.; Kumer, Sean C.

2016-01-01

Although data are available on the change of expression/activity of drug-metabolizing enzymes in liver cirrhosis patients, corresponding data on transporter protein expression are not available. Therefore, using quantitative targeted proteomics, we compared our previous data on noncirrhotic control livers (n = 36) with the protein expression of major hepatobiliary transporters, breast cancer resistance protein (BCRP), bile salt export pump (BSEP), multidrug and toxin extrusion protein 1 (MATE1), multidrug resistance–associated protein (MRP)2, MRP3, MRP4, sodium taurocholate–cotransporting polypeptide (NTCP), organic anion–transporting polypeptides (OATP)1B1, 1B3, 2B1, organic cation transporter 1 (OCT1), and P-glycoprotein (P-gp) in alcoholic (n = 27) and hepatitis C cirrhosis (n = 30) livers. Compared with control livers, the yield of membrane protein from alcoholic and hepatitis C cirrhosis livers was significantly reduced by 56 and 67%, respectively. The impact of liver cirrhosis on transporter protein expression was transporter-dependent. Generally, reduced protein expression (per gram of liver) was found in alcoholic cirrhosis livers versus control livers, with the exception that the expression of MRP3 was increased, whereas no change was observed for MATE1, MRP2, OATP2B1, and P-gp. In contrast, the impact of hepatitis C cirrhosis on protein expression of transporters (per gram of liver) was diverse, showing an increase (MATE1), decrease (BSEP, MRP2, NTCP, OATP1B3, OCT1, and P-gp), or no change (BCRP, MRP3, OATP1B1, and 2B1). The expression of hepatobiliary transporter protein differed in different diseases (alcoholic versus hepatitis C cirrhosis). Finally, incorporation of protein expression of OATP1B1 in alcoholic cirrhosis into the Simcyp physiologically based pharmacokinetics cirrhosis module improved prediction of the disposition of repaglinide in liver cirrhosis patients. These transporter expression data will be useful in the future to predict transporter-mediated drug disposition in liver cirrhosis patients. PMID:27543206

Multiple alterations of canalicular membrane transport activities in rats with CCl(4)-induced hepatic injury.

PubMed

Song, Im-Sook; Lee, Young-Mi; Chung, Suk-Jae; Shim, Chang-Koo

2003-04-01

The influence of CCl(4)-induced experimental hepatic injury (CCl(4)-EHI) on the expression and transport activities of primary active transporters on the canalicular membrane, including P-glycoprotein (P-gp), a bile salt export pump (Bsep) and a multidrug resistance associated protein2 (Mrp2), was assessed. CCl(4)-EHI was induced by an intraperitoneal injection of CCl(4) to rats at a dose of 1 ml/kg 24 h prior to the preparation of canalicular liver plasma membrane (cLPM) vesicles and pharmacokinetic studies. The expression of each transporter was measured for the vesicles via Western blot analysis at 6, 12, 24, 36, and 48 h after the injection of CCl(4). The in vivo canalicular excretion clearance (CL(exc)) of [(3)H]daunomycin, [(3)H]taurocholate and [(3)H]17beta-estradiol-17beta-D-glucuronide (E(2)17betaG), representative substrates of P-gp, Bsep, and Mrp2, respectively, was determined following an i.v. infusion to rats. The uptake of each substrate into cLPM vesicles in the presence of ATP was also measured by a rapid filtration technique. As the result of the CCl(4)-EHI, the protein level of transporters was altered as a function of time in multiple manners; it was increased by 3.6-fold for P-gp, unchanged for Bsep, and decreased by 73% for Mrp2 at 24 h. The in vivo CL(exc) and the intrinsic uptake clearance into cLPM vesicles (CL(int)) at 24 h after the CCl(4) injection (CCl(4)-EHI(24 h)) were also influenced by the EHI in a similar manner; they were increased by 1.8- and 1.9-fold for daunomycin, unchanged for taurocholate, and decreased by 41 and 39% for E(2)17betaG, respectively, consistent with multiple alterations in the expression of the relevant transporters.

Spatial patterns in salt marsh porewater dissolved organic matter over a spring-neap tidal cycle: insight to the impact of hydrodynamics on lateral carbon fluxes

NASA Astrophysics Data System (ADS)

Guimond, J. A.; Yu, X.; Duque, C.; Michael, H. A.

2016-12-01

Salt marshes are a hydrologically complex ecosystem. Tides deliver saline surface water to salt marshes via tidal creeks, and freshwater is introduced through lateral groundwater flow and vertical infiltration from precipitation. Locally, sediment heterogeneity, tides, weather, and topography introduce spatial and temporal complexities in groundwater-surface water interactions, which, in turn, can have a large impact on salt marsh biogeochemistry and the lateral fluxes of nutrients and carbon between the marsh platform and tidal creek. In this study, we investigate spatial patterns of porewater fluorescent dissolved organic matter (fDOM) and redox potential over a spring-neap tidal cycle in a mid-latitude tidal salt marsh in Dover, Delaware. Porewater samplers were used in conjunction with a peristaltic pump and YSI EXO Sonde to measure porewater fDOM, electrical conductivity, redox potential and pH from 0.5, 1.0, 1.5, 2.0, and 2.3 meters deep, as well as surface water from the creek and marsh platform. Eh was also measured continuously every 15 minutes with multi-level in-situ redox sensors at 0, 3, and 5m from the tidal creek, and water level and salinity were measured every 15 minutes continuously in 6 wells equipped with data loggers. Preliminary analyses indicate porewater salinity is dependent on the slope of the marsh platform, the elevation of the sample location, and the distance from a tidal creek. Near-creek redox analyses show tidal oscillations up to 300 mV; redox oscillations in the marsh interior show longer timescale changes. The observed redox oscillations coincide with the water level fluctuations at these locations. Therefore, lateral transport of carbon is determined by both hydrologic flow and biogeochemical processes. Results from this study provide insight into the timescales over which salt marsh hydrology impacts porewater biogeochemistry and the mechanisms controlling regional carbon cycling.

Dissolved inorganic nitrogen pools and surface flux under different brackish marsh vegetation types, common reed (Phragmites australis) and salt hay (Spartina patens)

USGS Publications Warehouse

Windham-Myers, L.

2005-01-01

The current expansion of Phragmites australis into the high marsh shortgrass (Spartina patens, Distichlis spicata) communities of eastern U.S. salt marshes provided an opportunity to identify the influence of vegetation types on pools and fluxes of dissolved inorganic nitrogen (DIN). Two brackish tidal marshes of the National Estuarine Research Reserve system were examined, Piermont Marsh of the Hudson River NERR in New York and Hog Island in the Jacques Coustaeu NERR of New Jersey. Pools of DIN in porewater and rates of DIN surface flux were compared in replicated pairs of recently-expanded P. australis and neighboring S. patens-dominated patches on the high marsh surface. Both marshes generally imported nitrate (NO3-) and exported ammonium (NH4+), such that overall DIN was exported. No differences in surface exchange of NO3- or NH4+ were observed between vegetation types. Depth-averaged porewater NH4+ concentrations over the entire growing season were 56% lower under P. australis than under S. patens (average 1.4 vs. 3.2 mg NH4+ L-1) with the most profound differences in November. Porewater profiles showed an accumulation of NH4+ at depth in S. patens and constant low concentrations in P. australis from the soil surface to 50 cm depth, with no significant differences in porewater salinity. Despite these profound differences in porewater, NH 4+ diffusion from soils of P. australis and S. patens were not measurably different, were similar to other published rates, and were well below estimated rates based on passive diffusion alone. Rapid adsorption and uptake by litter and microbes in surface soils of both communities may buffer NH4+ loss to flooding tides in both communities, thereby reducing the impact of P. australis invasion on NH4+ flux to flooding waters. ?? Springer 2005.

Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget

NASA Astrophysics Data System (ADS)

Duarte, Carlos M.

2017-01-01

Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain hidden in representations of the global carbon budget. Despite being confined to a narrow belt around the shoreline of the world's oceans, where they cover less than 7 million km2, vegetated coastal habitats support about 1 to 10 % of the global marine net primary production and generate a large organic carbon surplus of about 40 % of their net primary production (NPP), which is either buried in sediments within these habitats or exported away. Large, 10-fold uncertainties in the area covered by vegetated coastal habitats, along with variability about carbon flux estimates, result in a 10-fold bracket around the estimates of their contribution to organic carbon sequestration in sediments and the deep sea from 73 to 866 Tg C yr-1, representing between 3 % and 1/3 of oceanic CO2 uptake. Up to 1/2 of this carbon sequestration occurs in sink reservoirs (sediments or the deep sea) beyond these habitats. The organic carbon exported that does not reach depositional sites subsidizes the metabolism of heterotrophic organisms. In addition to a significant contribution to organic carbon production and sequestration, vegetated coastal habitats contribute as much to carbonate accumulation as coral reefs do. While globally relevant, the magnitude of global carbon fluxes supported by salt-marsh, mangrove, seagrass and macroalgal habitats is declining due to rapid habitat loss, contributing to loss of CO2 sequestration, storage capacity and carbon subsidies. Incorporating the carbon fluxes' vegetated coastal habitats' support into depictions of the carbon budget of the global ocean and its perturbations will improve current representations of the carbon budget of the global ocean.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melin, Alexander M.; Kisner, Roger A.; Drira, Anis

Embedded instrumentation and control systems that can operate in extreme environments are challenging due to restrictions on sensors and materials. As a part of the Department of Energy's Nuclear Energy Enabling Technology cross-cutting technology development programs Advanced Sensors and Instrumentation topic, this report details the design of a bench-scale embedded instrumentation and control testbed. The design goal of the bench-scale testbed is to build a re-configurable system that can rapidly deploy and test advanced control algorithms in a hardware in the loop setup. The bench-scale testbed will be designed as a fluid pump analog that uses active magnetic bearings tomore » support the shaft. The testbed represents an application that would improve the efficiency and performance of high temperature (700 C) pumps for liquid salt reactors that operate in an extreme environment and provide many engineering challenges that can be overcome with embedded instrumentation and control. This report will give details of the mechanical design, electromagnetic design, geometry optimization, power electronics design, and initial control system design.« less

Formation of recurring slope lineae on Mars by rarefied gas-triggered granular flows

NASA Astrophysics Data System (ADS)

Schmidt, F.; Andrieu, F.; Costard, F.; Kocifaj, M.; Meresescu, A. G.

2017-09-01

Recurring Slope Linae or RSL are seasonal dark features appearing when the soil reaches its maximum temperature. They appear on various slopes at the equator of Mars, in orientation depending on the season. Today, liquid water related processes have been promoted, such as deliquescence of salts. Nevertheless external atmospheric source of water is inconsistent with the observations. Internal source is also very unlikely. We take into consideration here the force occurring when the sun illuminates granular soil in rarefied gas conditions to produce a Knudsen pump. This process significantly lowers the angle of repose of sandy material. Hence, relatively low slope could start to flow. RSL seems to originate from rough terrains and boulders. We propose that the local shadows due to boulders over the soil, is the triggering phenomena. In this case, the Knudsen pump is magnified and could lead to flow. This new exotic dry process involving neither water nor CO2 and is consistent with the seasonal and facet's orientation appearance of RSL.

Wild Horse 69-kV transmission line environmental assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-12-01

Hill County Electric Cooperative Inc. (Hill County) proposes to construct and operate a 69-kV transmission line from its North Gildford Substation in Montana north to the Canadian border. A vicinity project area map is enclosed as a figure. TransCanada Power Corporation (TCP), a Canadian power-marketing company, will own and construct the connecting 69-kV line from the international border to Express Pipeline`s pump station at Wild Horse, Alberta. This Environmental Assessment is prepared for the Department of Energy (DOE) as lead federal agency to comply with the requirements of the National Environmental Policy Act (NEPA), as part of DOE`s review andmore » approval process of the applications filed by Hill County for a DOE Presidential Permit and License to Export Electricity to a foreign country. The purpose of the proposed line is to supply electric energy to a crude oil pump station in Canada, owned by Express Pipeline Ltd. (Express). The pipeline would transport Canadian-produced oil from Hardisty, Alberta, Canada, to Caster, Wyoming. The Express Pipeline is scheduled to be constructed in 1996--97 and will supply crude oil to refineries in Wyoming and the midwest.« less

Accounting System for Water Use by Vegetation in the Lower Colorado River Valley

USGS Publications Warehouse

Owen-Joyce, Sandra J.

1992-01-01

The Colorado River is the principal source of water in the valley of the Colorado River between Hoover Dam and the international boundary with Mexico (fig. 1). Agricultural, domestic, municipal, industrial, hydroelectric-power genera-tion, and recreation are the primary uses of river water in the valley. Most of the consumptive use of water from the river occurs downstream from Davis Dam, where water is diverted to irrigate crops along the river or is exported to interior regions of California and Arizona. Most of the agricultural areas are on the alluvium of the flood plain; in a few areas, land on the alluvial terraces has been cultivated. River water is consumed mainly by vegetation (crops and phreatophytes) on the flood plain. Crops were grown on 70.3 percent of the vegetated area classified by using 1984 digital image satellite data. Phreatophytes, natural vege-tation that obtain water from the alluvial aquifer, covered the remaining vegetated areas on the uncultivated flood plain. Most of the water used for irrigation is diverted or pumped from the river. In some areas, water is pumped from wells completed in the alluvial aquifer, which is hydraulically connected to the river.

Projected impact of climate change in the North and Baltic Sea. Results from dynamical downscaling of global CMIP climate scenarios

NASA Astrophysics Data System (ADS)

Gröger, Matthias; Maier-Reimer, Ernst; Mikolajewicz, Uwe; Sein, Dmitry

2013-04-01

Climate models have predicted strongest climate change impact for the mid/high lattiude areas. Despite their importance, shelves seas (which are supposed to account for more than 20% of global marine primary production and for up to 50% of total marine carbon uptake) are not adequately resolved in climate models. In this study, the global ocean general circulation and biogeochemistry model MPIOM/HAMOCC has been setup with an enhanced resolution over the NW European shelf (~10 km in the southern North Sea). For a realistic representation of atmosphere-ocean interactions the regional model REMO has been implemented. Thus, this model configuration allows a physically consistent simulation of climate signal propagation from the North Atlantic over the North Sea into the Baltic Sea since it interactively simulates mass and energy fluxes between the three basins. The results indicate substantial changes in hydrographic and biological conditions for the end of the 21st Century. A freshening by about 0.75 psu together with a surface warming of ~2.0 K and associated circulation changes in and outside the North Sea reduce biological production on the NW European shelf by ~35%. This reduction is twice as strong as the reduction in the open ocean. The underlying mechanism is a spatially well confined stratification feedback along the shelf break and the continental slope which reduces the winter mixed layer by locally more than 200 m compared to current conditions. As a consequence winter nutrient supply from the deep Atlantic declines between 40 and 50%. In addition to this, the volume transport of water and salt into the North Sea will slightly reduce (~10%) during summer. At the end of the 21st Century the North Sea appears nearly decoupled from the deep Atlantic. The projected decline in biological productivity and subsequent decrease of phytoplankton (by averaged 25%) will probably negatively affect the local fish stock in the North Sea. In the Baltic Sea the climate change impact is even stronger than in the North Sea. The surface temperature rises by 2.8 K and surface salinity declines by 1.3 psu. In the Gotland basin oxygen concentrations below 100m in the Baltic Sea reduce slowly and salt intrusion events from the North Sea become less frequent. This enhances the probability for extending hypoxic conditions in the Baltic Sea. The reproductive water volume for cod decreases by 25% towards the end of the simulations with main drops in the 1980'ies and 2020'ies. Due to the reduced biological production CO2 uptake in the North Sea is lowered by 1/3 at the end of the 21st Century compared to the end of the 20th Century implying a strong weakening of shelf carbon pumping. Contrary to previous studies, our results indicate that the North Sea acts only as a very weak carbon shelf pump. This is because most of the water exported to the open ocean remains within the mixed layer, where it is still exposed to the atmosphere. For the North Sea we estimate that currently only 20% of the absorbed carbon is stored for longer in the open ocean.

Innovative Phase Change Thermal Energy Storage Solution for Baseload Power Phase 1 Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu, Songgang

2013-05-15

The primary purpose of this project is to develop and validate an innovative, scalable phase change salt thermal energy storage (TES) system that can interface with Infinia’s family of free-piston Stirling engines (FPSE). This TES technology is also appropriate for Rankine and Brayton power converters. Solar TES systems based on latent heat of fusion rather than molten salt temperature differences, have many advantages that include up to an order of magnitude higher energy storage density, much higher temperature operation, and elimination of pumped loops for most of Infinia’s design options. DOE has funded four different concepts for solar phase changemore » TES, including one other Infinia awarded project using heat pipes to transfer heat to and from the salt. The unique innovation in this project is an integrated TES/pool boiler heat transfer system that is the simplest approach identified to date and arguably has the best potential for minimizing the levelized cost of energy (LCOE). The Phase 1 objectives are to design, build and test a 1-hour TES proof-of-concept lab demonstrator integrated with an Infinia 3 kW Stirling engine, and to conduct a preliminary design of a 12-hour TES on-sun prototype.« less

West Hackberry Strategic Petroleum Reserve site brine-disposal monitoring, Year I report. Volume II. Physical and chemical oceanography. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeRouen, L.R.; Hann, R.W.; Casserly, D.M.

1983-02-01

This project centers around the Strategic Petroleum Site (SPR) known as the West Hackberry salt dome which is located in southwestern Louisiana, and which is designed to store 241 million barrels of crude oil. Oil storage caverns are formed by injecting water into salt deposits, and pumping out the resulting brine. Studies described in this report were designed as follow-on studies to three months of pre-discharge characterization work, and include data collected during the first year of brine leaching operations. The objectives were to: (1) characterize the environment in terms of physical, chemical and biological attributes; (2) determine if significantmore » adverse changes in ecosystem productivity and stability of the biological community are occurring as a result of brine discharge; and (3) determine the magnitude of any change observed. Contents of Volume II include: introduction; physical oceanography; estuarine hydrology and hydrography; analysis of discharge plume; and water and sediment quality.« less

Synthesis of sintering-resistant sorbents for CO2 capture.

PubMed

Liu, Wenqiang; Feng, Bo; Wu, Yueqin; Wang, Guoxiong; Barry, John; da Costa, João C Diniz

2010-04-15

Sorbents for high temperature CO2 capture are under intensive development owing to their potential applications in advanced zero emission power, sorption-enhanced steam methane reforming for hydrogen production and energy storage systems in chemical heat pumps. One of the challenges in the development is the prevention of sintering of the sorbent (normally a calcium oxide derivative) which causes the CO2 capture capacity of the material to deteriorate rapidly after a few cycles of utilization. Here we show that a simple wet mixing method can produce sintering-resistant sorbents from calcium and magnesium salts of d-gluconic acid. It was found that calcium oxide was well distributed in the sorbents with metal oxide nanoparticles on the surface acting as physical barriers, and the CO2 capture capacity of the sorbents was largely maintained over multiple cycles of utilization. This method was also applied to other organometallic salts of calcium and magnesium/aluminum and the produced sorbents showed similarly high reversibility.

Analysis of Tank 38H (HTF-38-15-119, 127) Surface, Subsurface and Tank 43H (HTF-43-15-116, 117 and 118) Surface, Feed Pump Suction and Jet Suction Subsurface Supernatant Samples in Support of Enrichment, Corrosion Control and Salt Batch Planning Programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L.

Compositional feed limits have been established to ensure that a nuclear criticality event for the 2H and 3H Evaporators is not possible. The Enrichment Control Program (ECP) requires feed sampling to determine the equivalent enriched uranium content prior to transfer of waste other than recycle transfers (requires sampling to determine the equivalent enriched uranium at two locations in Tanks 38H and 43H every 26 weeks) The Corrosion Control Program (CCP) establishes concentration and temperature limits for key constituents and periodic sampling and analysis to confirm that waste supernate is within these limits. This report provides the results of analyses onmore » Tanks 38H and 43H surface and subsurface supernatant liquid samples in support of the ECP, the CCP, and the Salt Batch 10 Planning Program.« less

Preconceptual design of a fluoride high temperature salt-cooled engineering demonstration reactor: Motivation and overview

DOE PAGES

Qualls, A. Louis; Betzler, Benjamin R.; Brown, Nicholas R.; ...

2016-12-21

Engineering demonstration reactors are nuclear reactors built to establish proof of concept for technology options that have never been built. Examples of engineering demonstration reactors include Peach Bottom 1 for high temperature gas-cooled reactors (HTGRs) and Experimental Breeder Reactor-II (EBR-II) for sodium-cooled fast reactors. Historically, engineering demonstrations have played a vital role in advancing the technology readiness level of reactor technologies. Our paper details a preconceptual design for a fluoride salt-cooled engineering demonstration reactor. The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would usemore » tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 7LiF-BeF2) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. The design philosophy of the FHR DR was focused on safety, near-term deployment, and flexibility. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated as an engineering demonstration with minimal risk and cost. These technologies include TRISO particle fuel, replaceable core structures, and consistent structural material selection for core structures and the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Important capabilities to be demonstrated by building and operating the FHR DR include fabrication and operation of high temperature reactors; heat exchanger performance (including passive decay heat removal); pump performance; and reactivity control; salt chemistry control to maximize vessel life; tritium management; core design methodologies; salt procurement, handling, maintenance and ultimate disposal. It is recognized that non-nuclear separate and integral test efforts (e.g., heated salt loops or loops using simulant fluids) are necessary to develop the technologies that will be demonstrated in the FHR DR.« less

Preconceptual design of a fluoride high temperature salt-cooled engineering demonstration reactor: Motivation and overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qualls, A. Louis; Betzler, Benjamin R.; Brown, Nicholas R.

Engineering demonstration reactors are nuclear reactors built to establish proof of concept for technology options that have never been built. Examples of engineering demonstration reactors include Peach Bottom 1 for high temperature gas-cooled reactors (HTGRs) and Experimental Breeder Reactor-II (EBR-II) for sodium-cooled fast reactors. Historically, engineering demonstrations have played a vital role in advancing the technology readiness level of reactor technologies. Our paper details a preconceptual design for a fluoride salt-cooled engineering demonstration reactor. The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would usemore » tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 7LiF-BeF2) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. The design philosophy of the FHR DR was focused on safety, near-term deployment, and flexibility. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated as an engineering demonstration with minimal risk and cost. These technologies include TRISO particle fuel, replaceable core structures, and consistent structural material selection for core structures and the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Important capabilities to be demonstrated by building and operating the FHR DR include fabrication and operation of high temperature reactors; heat exchanger performance (including passive decay heat removal); pump performance; and reactivity control; salt chemistry control to maximize vessel life; tritium management; core design methodologies; salt procurement, handling, maintenance and ultimate disposal. It is recognized that non-nuclear separate and integral test efforts (e.g., heated salt loops or loops using simulant fluids) are necessary to develop the technologies that will be demonstrated in the FHR DR.« less

Local and regional scale exchanges of dissolved organic carbon (DOC) between tidal wetlands and their adjacent coastal waters

NASA Astrophysics Data System (ADS)

Osburn, C. L.; Joshi, I.; Lebrasse, M. C.; Oviedo-Vargas, D.; Bianchi, T. S.; Bohnenstiehl, D. R.; D'Sa, E. J.; He, R.; Ko, D.; Arellano, A.; Ward, N. D.

2017-12-01

The contribution of blue carbon from tidal wetlands to the coastal ocean in the form of dissolved organic carbon (DOC) represents a terrestrial-aquatic linkage of increasing importance. DOC flux results will be presented from local (tidal creek) and regional (bays) scale studies in which various combinations of field observations, ocean-color satellite observations, and the outputs of high-resolution hydrodynamic models were used to estimate DOC export. The first project was located in Bald Head Creek, a tributary to the Cape Fear River estuary in eastern North Carolina (NC). DOC fluxes were computed using a bathymetric data collected via unmanned surface vehicle (USV) and a numerical hydrodynamic model (SCHISM) based on the relationships between colored dissolved organic matter (CDOM) absorption, DOC concentration, and salinity taken from field observations. Model predictions estimated an annual net export of DOC at 54 g C m-2 yr-1 from the tidal creek to the adjacent estuary. Carbon stable isotope (δ13C) values were used to estimate the contribution of wetland carbon to this export. In the second project, DOC fluxes from the Apalachicola Bay, FL, Barataria Bay, LA, were based on the development of algorithms between DOC and CDOM absorption derived from the VIIRS ocean color sensor. The Navy Coastal Ocean Model (NCOM) was used to compute salt flux estimates from each bay to the Louisiana-Texas shelf. The relationship between salinity and CDOM was used to estimate net annual DOC exports of 8.35 x 106 g C m-2 y-1 (Apalachicola Bay) and 7.14 x 106 g C m-2 yr-1 (Barataria Bay). These values approximate 13% and 9% of the annual loads of DOC from the Mississippi River to the Gulf of Mexico, respectively. CDOM and lignin were used in a mixing model to estimate wetland-derived DOC were 2% for Apalachicola Bay and 13% for Barataria Bay, the latter having one of the highest rates of relative sea level rise in North America. Results from our project demonstrated the utility of CDOM, amenable to high resolution observations from multiple platforms, as a basis for constraining the heterogeneity of DOC exports from tidal wetlands to estuaries and coastal waters using numerical models at local and regional scales.

DEVELOPMENT OF AN INSOLUBLE SALT SIMULANT TO SUPPORT ENHANCED CHEMICAL CLEANING TESTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eibling, R

The closure process for high level waste tanks at the Savannah River Site will require dissolution of the crystallized salts that are currently stored in many of the tanks. The insoluble residue from salt dissolution is planned to be removed by an Enhanced Chemical Cleaning (ECC) process. Development of a chemical cleaning process requires an insoluble salt simulant to support evaluation tests of different cleaning methods. The Process Science and Engineering section of SRNL has been asked to develop an insoluble salt simulant for use in testing potential ECC processes (HLE-TTR-2007-017). An insoluble salt simulant has been developed based uponmore » the residues from salt dissolution of saltcake core samples from Tank 28F. The simulant was developed for use in testing SRS waste tank chemical cleaning methods. Based on the results of the simulant development process, the following observations were developed: (1) A composition based on the presence of 10.35 grams oxalate and 4.68 grams carbonate per 100 grams solids produces a sufficiently insoluble solids simulant. (2) Aluminum observed in the solids remaining from actual waste salt dissolution tests is probably precipitated from sodium aluminate due to the low hydroxide content of the saltcake. (3) In-situ generation of aluminum hydroxide (by use of aluminate as the Al source) appears to trap additional salts in the simulant in a manner similar to that expected for actual waste samples. (4) Alternative compositions are possible with higher oxalate levels and lower carbonate levels. (5) The maximum oxalate level is limited by the required Na content of the insoluble solids. (6) Periodic mixing may help to limit crystal growth in this type of salt simulant. (7) Long term storage of an insoluble salt simulant is likely to produce a material that can not be easily removed from the storage container. Production of a relatively fresh simulant is best if pumping the simulant is necessary for testing purposes. The insoluble salt simulant described in this report represents the initial attempt to represent the material which may be encountered during final waste removal and tank cleaning. The final selected simulant was produced by heating and evaporation of a salt slurry sample to remove excess water and promote formation and precipitation of solids with solubility characteristics which are consistent with actual tank insoluble salt samples. The exact anion composition of the final product solids is not explicitly known since the chemical components in the final product are distributed between the solid and liquid phases. By combining the liquid phase analyses and total solids analysis with mass balance requirements a calculated composition of assumed simple compounds was obtained and is shown in Table 0-1. Additional improvements to and further characterization of the insoluble salt simulant are possible. During the development of these simulants it was recognized that: (1) Additional waste characterization on the residues from salt dissolution tests with actual waste samples to determine the amount of species such as carbonate, oxalate and aluminosilicate would allow fewer assumptions to be made in constructing an insoluble salt simulant. (2) The tank history will impact the amount and type of insoluble solids that exist in the salt dissolution solids. Varying the method of simulant production (elevated temperature processing time, degree of evaporation, amount of mixing (shear) during preparation, etc.) should be tested.« less

CD147 regulates the expression of MCT1 and lactate export in multiple myeloma cells

PubMed Central

Walters, Denise K; Arendt, Bonnie K; Jelinek, Diane F

2013-01-01

Increased use of the glycolytic pathway, even in the presence of oxygen, has recently been recognized as a key characteristic of malignant cells. However, the glycolytic phenotype results in increased lactic acid production and, in order to prevent cellular acidosis, tumor cells must increase proton efflux via upregulation of pH regulators such as proton-pumps, sodium-proton exchangers, and/or monocarboxylate transporters (MCT) (e.g., MCT1, MCT4). Interestingly, expression of MCT1 and MCT4 has been previously shown to be dependent upon expression of the transmembrane glycoprotein CD147. Recently, we demonstrated that primary patient multiple myeloma (MM) cells and human MM cell lines (HMCLs) overexpress CD147. Therefore, the goal of the current study was to specifically determine if MCT1 and MCT4 were also overexpressed in MM cells. RT-PCR analysis demonstrated both primary patient MM cells and HMCLs overexpress MCT1 and MCT4 mRNA. Notably, primary MM cells or HMCLs were found to express variable levels of MCT1 and/or MCT4 at the protein level despite CD147 expression. In those HMCLs positive for MCT1 and/or MCT4 protein expression, MCT1 and/or MCT4 were found to be associated with CD147. Specific siRNA-mediated downregulation of MCT1 but not MCT4 resulted in decreased HMCL proliferation, decreased lactate export, and increased cellular media pH. However, western blot analysis revealed that downregulation of MCT1 also downregulated CD147 and vice versa despite no effect on mRNA levels. Taken together, these data demonstrate the association between MCT1 and CD147 proteins in MM cells and importance of their association for lactate export and proliferation in MM cells. PMID:24013424

CD147 regulates the expression of MCT1 and lactate export in multiple myeloma cells.

PubMed

Walters, Denise K; Arendt, Bonnie K; Jelinek, Diane F

2013-10-01

Increased use of the glycolytic pathway, even in the presence of oxygen, has recently been recognized as a key characteristic of malignant cells. However, the glycolytic phenotype results in increased lactic acid production and, in order to prevent cellular acidosis, tumor cells must increase proton efflux via upregulation of pH regulators such as proton-pumps, sodium-proton exchangers, and/or monocarboxylate transporters (MCT) (e.g., MCT1, MCT4). Interestingly, expression of MCT1 and MCT4 has been previously shown to be dependent upon expression of the transmembrane glycoprotein CD147. Recently, we demonstrated that primary patient multiple myeloma (MM) cells and human MM cell lines (HMCLs) overexpress CD147. Therefore, the goal of the current study was to specifically determine if MCT1 and MCT4 were also overexpressed in MM cells. RT-PCR analysis demonstrated both primary patient MM cells and HMCLs overexpress MCT1 and MCT4 mRNA. Notably, primary MM cells or HMCLs were found to express variable levels of MCT1 and/or MCT4 at the protein level despite CD147 expression. In those HMCLs positive for MCT1 and/or MCT4 protein expression, MCT1 and/or MCT4 were found to be associated with CD147. Specific siRNA-mediated downregulation of MCT1 but not MCT4 resulted in decreased HMCL proliferation, decreased lactate export, and increased cellular media pH. However, western blot analysis revealed that downregulation of MCT1 also downregulated CD147 and vice versa despite no effect on mRNA levels. Taken together, these data demonstrate the association between MCT1 and CD147 proteins in MM cells and importance of their association for lactate export and proliferation in MM cells.

Migrant biomass and respiratory carbon flux by zooplankton and micronekton in the subtropical northeast Atlantic Ocean (Canary Islands)

NASA Astrophysics Data System (ADS)

Ariza, A.; Garijo, J. C.; Landeira, J. M.; Bordes, F.; Hernández-León, S.

2015-05-01

Diel Vertical Migration (DVM) in marine ecosystems is performed by zooplankton and micronekton, promoting a poorly accounted export of carbon to the deep ocean. Major efforts have been made to estimate carbon export due to gravitational flux and to a lesser extent, to migrant zooplankton. However, migratory flux by micronekton has been largely neglected in this context, due to its time-consuming and difficult sampling. In this paper, we evaluated gravitational and migratory flux due to the respiration of zooplankton and micronekton in the northeast subtropical Atlantic Ocean (Canary Islands). Migratory flux was addressed by calculating the biomass of migrating components and measuring the electron transfer system (ETS) activity in zooplankton and dominant species representing micronekton (Euphausia gibboides, Sergia splendens and Lobianchia dofleini). Our results showed similar biomass in both components. The main taxa contributing to DVM within zooplankton were juvenile euphausiids, whereas micronekton were mainly dominated by fish, followed by adult euphausiids and decapods. The contribution to respiratory flux of zooplankton (3.4 ± 1.9 mg C m-2 d-1) was similar to that of micronekton (2.9 ± 1.0 mg C m-2 d-1). In summary, respiratory flux accounted for 53% (range 23-71) of the gravitational flux measured at 150 m depth (11.9 ± 5.8 mg C m-2 d-1). However, based on larger migratory ranges and gut clearance rates, micronekton are expected to be the dominant component that contributes to carbon export in deeper waters. Micronekton estimates in this paper as well as those in existing literature, although variable due to regional differences and difficulties in calculating their biomass, suggest that carbon fluxes driven by this community are important for future models of the biological carbon pump.

Source of salts in the Waianae part of the Pearl Harbor aquifer near Barbers Point water tunnel, Oahu, Hawaii

USGS Publications Warehouse

Eyre, P.R.

1987-01-01

The salinity of the water supply of Barbers Point Naval Air Station has increased markedly since 1983. The Naval Air Station obtains its water, about 3 million gal/day, from Barbers Point shaft, a water shaft that taps the Waianae part of the Pearl Harbor aquifer underlying the dry, southeastern flank of the Waianae mountains on the island on Oahu, Hawaii. From 1983 to 1985 the chloride concentration of the water, increased from 220 to 250 mg/L and has remained near that level through 1986. The EPA has established 250 mg/L as the maximum recommended chloride concentration in drinking water because above that level many people can taste the salt. The high chloride concentration in shallow groundwater at all wells in the area indicates that most of the salts in the freshwater lens are contributed by rainfall, sea spray, and irrigation return water. At Barbers Point shaft, pumping may draw a small amount of saltwater from the transition zone and increase the chloride concentration in the pumped water by about 20 mg/L. Salinity of the lens decreases progressively inland in response to recharge from relatively fresher water and in response to an increasing lens thickness with increasing distance from the shoreline. The increase, in 1983, in the chloride concentration of water at the shaft was most probably the result of saltier recharge water reaching the water table, and not the result of increased mixing of underlying saltwater with the freshwater. The chloride concentration of the recharge water has probably increased because, in 1980, the drip method of irrigation began to replace the furrow method on sugarcane fields near the shaft. A mixing-cell model was used to estimate the effect of drip irrigation on the chloride concentration of the groundwater in the vicinity of Barbers Point shaft. The model predicted an increase in chloride concentration of about 50 mg/L. The observed increase was about 30 mg/L and the chloride concentration is presently stable at 245 to 250 mg/L; hence, the chloride concentration is not expected to increase significantly more. (Lantz-PTT)

Role of the HaHOG1 MAP Kinase in Response of the Conifer Root and But Rot Pathogen (Heterobasidion annosum) to Osmotic and Oxidative Stress

PubMed Central

Raffaello, Tommaso; Keriö, Susanna; Asiegbu, Fred O.

2012-01-01

The basidiomycete Heterobasidion annosum (Fr.) Bref. s.l. is a filamentous white rot fungus, considered to be the most economically important pathogen of conifer trees. Despite the severity of the tree infection, very little is known about the molecular and biochemical aspects related to adaptation to abiotic stresses. In this study, the osmotic and oxidative tolerance as well as the role of the HaHOG1 Mitogen Activated Protein Kinase (MAPK) gene were investigated. The transcript levels of the yeast orthologues GPD1, HSP78, STL1, GRE2 and the ATPase pumps ENA1, PMR1, PMC1 known to have an important role in osmotolerance were also quantified under salt osmotic conditions. The HaHOG1 gene was used for a heterologous expression and functional study in the Saccharomyces cerevisiae Δhog1 strain. Moreover, the phosphorylation level of HaHog1p was studied under salt osmotic and oxidative stress. The result showed that H. annosum displayed a decreased growth when exposed to an increased concentration of osmotic and oxidative stressors. GPD1, HSP78, STL1 and GRE2 showed an induction already at 10 min after exposure to salt stress. Among the ATPase pumps studied, PMC1 was highly induced when the fungus was exposed to 0.2 M CaCl2 for 60 min. The heterologous expression of the HaHOG1 sequence in yeast confirmed that the gene is able to restore the osmotolerance and oxidative tolerance in the S. cerevisiae hog1Δ mutant strain. The HaHog1p was strongly phosphorylated in the presence of NaCl, KCl, H2O2 but not in the presence of CaCl2 and MgCl2. The GFP-HaHog1p fusion protein accumulated in the nuclei of the S. cerevisiae hog1Δ cells when exposed to high osmotic conditions but not under oxidative stress. These results provide the first insights about the response of H. annosum to osmotic and oxidative stress and elucidate the role of the HaHOG1 gene in such conditions. PMID:22319614

Microsystems in medicine.

PubMed

Wallrabe, U; Ruther, P; Schaller, T; Schomburg, W K

1998-03-01

The complexity of modern surgical and analytical methods requires the miniaturisation of many medical devices. The LIGA technique and also mechanical microengineering are well known for the batch fabrication of microsystems. Actuators and sensors are developed based on these techniques. The hydraulic actuation principle is advantageous for medical applications since the energy may be supplied by pressurised balanced salt solution. Some examples are turbines, pumps and valves. In addition, optical sensors and components are useful for analysis and inspection as represented by microspectrometers and spherical lenses. Finally, plastic containers with microporous bottoms allow a 3-dimensional growth of cell culture systems.

DsSWEET17, a Tonoplast-Localized Sugar Transporter from Dianthus spiculifolius, Affects Sugar Metabolism and Confers Multiple Stress Tolerance in Arabidopsis.

PubMed

Zhou, Aimin; Ma, Hongping; Feng, Shuang; Gong, Shufang; Wang, Jingang

2018-05-24

Plant SWEETs (Sugars Will Eventually be Exported Transporters) affect the growth of plants by regulating the transport of sugar from source to sink and its intracellular transport between different organelles. In this study, DsSWEET17 from Dianthus spiculifolius was identified and characterized. Real-time quantitative PCR analysis revealed that the expression of DsSWEET17 was affected by exogenous application of fructose and glucose as well as under salt, osmotic, and oxidation stress. Colocalization experiments showed that the DsSWEET17-GFP (green fluorescent protein) fusion protein was localized to the FM4-64-labeled tonoplasts in Arabidopsis . Compared to the wild type, the transgenic Arabidopsis seedlings overexpressing DsSWEET17 had longer roots, greater fresh weight, and a faster root growth upon exogenous application of fructose. Furthermore, transgenic Arabidopsis seedlings had significantly higher fructose accumulation than was observed for the wild-type seedlings. The analysis of root length revealed that transgenic Arabidopsis had higher tolerance to salt, osmotic, and oxidative stresses. Taken together, our results suggest that DsSWEET17 may be a tonoplast sugar transporter, and its overexpression affects sugar metabolism and confers multiple stress tolerance in Arabidopsis .

The Arabidopsis DESPERADO/AtWBC11 Transporter Is Required for Cutin and Wax Secretion1[C][W

PubMed Central

Panikashvili, David; Savaldi-Goldstein, Sigal; Mandel, Tali; Yifhar, Tamar; Franke, Rochus B.; Höfer, René; Schreiber, Lukas; Chory, Joanne; Aharoni, Asaph

2007-01-01

The cuticle fulfills multiple roles in the plant life cycle, including protection from environmental stresses and the regulation of organ fusion. It is largely composed of cutin, which consists of C16-18 fatty acids. While cutin composition and biosynthesis have been studied, the export of cutin monomers out of the epidermis has remained elusive. Here, we show that DESPERADO (AtWBC11) (abbreviated DSO), encoding a plasma membrane-localized ATP-binding cassette transporter, is required for cutin transport to the extracellular matrix. The dso mutant exhibits an array of surface defects suggesting an abnormally functioning cuticle. This was accompanied by dramatic alterations in the levels of cutin monomers. Moreover, electron microscopy revealed unusual lipidic cytoplasmatic inclusions in epidermal cells, disappearance of the cuticle in postgenital fusion areas, and altered morphology of trichomes and pavement cells. We also found that DSO is induced by salt, abscisic acid, and wounding stresses and its loss of function results in plants that are highly susceptible to salt and display reduced root branching. Thus, DSO is not only essential for developmental plasticity but also plays a vital role in stress responses. PMID:17951461

The Arabidopsis DESPERADO/AtWBC11 transporter is required for cutin and wax secretion.

PubMed

Panikashvili, David; Savaldi-Goldstein, Sigal; Mandel, Tali; Yifhar, Tamar; Franke, Rochus B; Höfer, René; Schreiber, Lukas; Chory, Joanne; Aharoni, Asaph

2007-12-01

The cuticle fulfills multiple roles in the plant life cycle, including protection from environmental stresses and the regulation of organ fusion. It is largely composed of cutin, which consists of C(16-18) fatty acids. While cutin composition and biosynthesis have been studied, the export of cutin monomers out of the epidermis has remained elusive. Here, we show that DESPERADO (AtWBC11) (abbreviated DSO), encoding a plasma membrane-localized ATP-binding cassette transporter, is required for cutin transport to the extracellular matrix. The dso mutant exhibits an array of surface defects suggesting an abnormally functioning cuticle. This was accompanied by dramatic alterations in the levels of cutin monomers. Moreover, electron microscopy revealed unusual lipidic cytoplasmatic inclusions in epidermal cells, disappearance of the cuticle in postgenital fusion areas, and altered morphology of trichomes and pavement cells. We also found that DSO is induced by salt, abscisic acid, and wounding stresses and its loss of function results in plants that are highly susceptible to salt and display reduced root branching. Thus, DSO is not only essential for developmental plasticity but also plays a vital role in stress responses.

The influence of erythrocyte maturity on ion transport and membrane lipid composition in the rat.

PubMed

Vokurková, M; Rauchová, H; Dobešová, Z; Loukotová, J; Nováková, O; Kuneš, J; Zicha, J

2016-01-01

Significant relationships between ion transport and membrane lipid composition (cholesterol, total phospholipids and sphingomyelins) were found in erythrocytes of salt hypertensive Dahl rats. In these animals mean cellular hemoglobin content correlated negatively with Na(+)-K(+) pump activity and Na(+) leak but positively with Na(+)-K(+) cotransport activity. Immature erythrocytes exhibit lower mean cellular hemoglobin content (MCHC) than mature ones. The aim of the present study was to find a relationship between erythrocyte maturity, membrane lipid composition and ion transport activity in Wistar rats aged three months which were subjected to repeated hemorrhage (blood loss 2 ml/day for 6 days) to enrich circulating erythrocytes with immature forms. Immature and mature erythrocyte fractions in control and hemorrhaged rats were separated by repeated centrifugation. Hemorrhaged rats had increased number of reticulocytes but reduced hematocrit and MCHC compared to control rats. Immature erythrocytes of hemorrhaged rats differed from mature ones of control animals by elevated Na(+)-K(+) pump activity, reduced Na(+)-K(+) cotransport activity and increased Rb(+) leak. These ion transport changes in immature erythrocytes were accompanied by higher concentration of total phospholipids in their cell membranes. Membrane phospholipid content correlated positively with Na(+)-K(+) pump activity and cation leaks but negatively with Na(+)-K(+) cotransport activity. Moreover, they were also negatively related with MCHC which correlated negatively with Na(+)-K(+) pump activity and Rb(+) leak but positively with Na(+)-K(+) cotransport activity. Thus certain abnormalities of erythrocyte ion transport and membrane lipid composition detected in hypertensive animals might be caused by higher incidence of immature cells.

Coccolithovirus facilitation of carbon export in the North Atlantic.

PubMed

Laber, Christien P; Hunter, Jonathan E; Carvalho, Filipa; Collins, James R; Hunter, Elias J; Schieler, Brittany M; Boss, Emmanuel; More, Kuldeep; Frada, Miguel; Thamatrakoln, Kimberlee; Brown, Christopher M; Haramaty, Liti; Ossolinski, Justin; Fredricks, Helen; Nissimov, Jozef I; Vandzura, Rebecca; Sheyn, Uri; Lehahn, Yoav; Chant, Robert J; Martins, Ana M; Coolen, Marco J L; Vardi, Assaf; DiTullio, Giacomo R; Van Mooy, Benjamin A S; Bidle, Kay D

2018-05-01

Marine phytoplankton account for approximately half of global primary productivity 1 , making their fate an important driver of the marine carbon cycle. Viruses are thought to recycle more than one-quarter of oceanic photosynthetically fixed organic carbon 2 , which can stimulate nutrient regeneration, primary production and upper ocean respiration 2 via lytic infection and the 'virus shunt'. Ultimately, this limits the trophic transfer of carbon and energy to both higher food webs and the deep ocean 2 . Using imagery taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite, along with a suite of diagnostic lipid- and gene-based molecular biomarkers, in situ optical sensors and sediment traps, we show that Coccolithovirus infections of mesoscale (~100 km) Emiliania huxleyi blooms in the North Atlantic are coupled with particle aggregation, high zooplankton grazing and greater downward vertical fluxes of both particulate organic and particulate inorganic carbon from the upper mixed layer. Our analyses captured blooms in different phases of infection (early, late and post) and revealed the highest export flux in 'early-infected blooms' with sinking particles being disproportionately enriched with infected cells and subsequently remineralized at depth in the mesopelagic. Our findings reveal viral infection as a previously unrecognized ecosystem process enhancing biological pump efficiency.

Efflux pumps as antimicrobial resistance mechanisms.

PubMed

Poole, Keith

2007-01-01

Antibiotic resistance continues to hamper antimicrobial chemotherapy of infectious disease, and while biocide resistance outside of the laboratory is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are not uncommon. Efflux mechanisms, both drug-specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials in important human pathogens. Multidrug efflux mechanisms are generally chromosome-encoded, with their expression typically resultant from mutations in regulatory genes, while drug-specific efflux mechanisms are encoded by mobile genetic elements whose acquisition is sufficient for resistance. While it has been suggested that drug-specific efflux systems originated from efflux determinants of self-protection in antibiotic-producing Actinomycetes, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, are appreciated as having an intended housekeeping function unrelated to drug export and resistance. Thus, it will be important to elucidate the intended natural function of these efflux mechanisms in order, for example, to anticipate environmental conditions or circumstances that might promote their expression and, so, compromise antimicrobial chemotherapy. Given the clinical significance of antimicrobial exporters, it is clear that efflux must be considered in formulating strategies for treatment of drug-resistant infections, both in the development of new agents, for example, less impacted by efflux or in targeting efflux directly with efflux inhibitors.

Enhanced Particulate Organic Carbon Export at Eddy Edges in the Oligotrophic Western North Pacific Ocean

PubMed Central

Shih, Yung-Yen; Hung, Chin-Chang; Gong, Gwo-Ching; Chung, Wan-Chen; Wang, Yu-Huai; Lee, I-Huan; Chen, Kuo-Shu; Ho, Chuang-Yi

2015-01-01

Mesoscale eddies in the subtropical oligotrophic ocean are ubiquitous and play an important role in nutrient supply and oceanic primary production. However, it is still unclear whether these mesoscale eddies can efficiently transfer CO2 from the atmosphere to deep waters via biological pump because of the sampling difficulty due to their transient nature. In 2007, particulate organic carbon (POC) fluxes, measured below the euphotic zone at the edge of warm eddy were 136–194 mg-C m−2 d−1 which was greatly elevated over that (POC flux = 26–35 mg-C m−2 d−1) determined in the nutrient-depleted oligotrophic waters in the Western North Pacific (WNP). In 2010, higher POC fluxes (83–115 mg-C m−2 d−1) were also observed at the boundary of mesoscale eddies in the WNP. The enhanced POC flux at the edge of eddies was mainly attributed to both large denuded diatom frustules and zooplankton fecal pellets based on scanning electron microscopy (SEM) examination. The result suggests that mesoscale eddies in the oligotrophic waters in the subtropical WNP can efficiently increase the oceanic carbon export flux and the eddy edge is a crucial conduit in carbon sequestration to deep waters. PMID:26171611

Increased Usage of Antiseptics Is Associated with Reduced Susceptibility in Clinical Isolates of Staphylococcus aureus.

PubMed

Hardy, Katherine; Sunnucks, Katie; Gil, Hannah; Shabir, Sahida; Trampari, Eleftheria; Hawkey, Peter; Webber, Mark

2018-05-29

Hospital-acquired infection is a major cause of morbidity and mortality, and regimes to prevent infection are crucial in infection control. These include the decolonization of vulnerable patients with methicillin-resistant Staphylococcus aureus (MRSA) carriage using antiseptics, including chlorhexidine and octenidine. Concern has been raised, however, regarding the possible development of biocide resistance. In this study, we assembled a panel of S. aureus isolates, including isolates collected before the development of chlorhexidine and octenidine and isolates, from a major hospital trust in the United Kingdom during a period when the decolonization regimes were altered. We observed significant increases in the MIC and minimum bactericidal concentration (MBC) of chlorhexidine in isolates from periods of high usage of chlorhexidine. Isolates with increased MICs and MBCs of octenidine rapidly emerged after octenidine was introduced in the trust. There was no apparent cross-resistance between the two biocidal agents. A combination of variable-number tandem repeat (VNTR) analysis, PCR for qac genes, and whole-genome sequencing was used to type isolates and examine possible mechanisms of resistance. There was no expansion of a single strain associated with decreased biocide tolerance, and biocide susceptibility did not correlate with carriage of qac efflux pump genes. Mutations within the NorA or NorB efflux pumps, previously associated with chlorhexidine export, were identified, however, suggesting that this may be an important mechanism of biocide tolerance. We present evidence that isolates are evolving in the face of biocide challenge in patients and that changes in decolonization regimes are reflected in changes in susceptibility of isolates. IMPORTANCE Infection in hospitals remains a major cause of death and disease. One way in which we combat this is by decolonizing at-risk patients from carriage of bacteria which can cause disease such as MRSA. This is done with antiseptics, including chlorhexidine and octenidine. There is concern, however, that bacteria may be able to become resistant to these antiseptics. In this study, we looked at isolates of MRSA and found that there was a correlation between the use of antiseptics and increased resistance in the isolates. We also suggest that the mechanism by which these more tolerant isolates may become resistant to antiseptics is that of changing a transport pump that exports these agents. This information suggests that we need to study the impact of antiseptics on clinically important bacteria more closely. Copyright © 2018 Hardy et al.

Sediment dynamics in the lower Mekong River: Transition from tidal river to estuary

NASA Astrophysics Data System (ADS)

Nowacki, Daniel J.; Ogston, Andrea S.; Nittrouer, Charles A.; Fricke, Aaron T.; Van, Pham Dang Tri

2015-09-01

A better understanding of flow and sediment dynamics in the lowermost portions of large-tropical rivers is essential to constraining estimates of worldwide sediment delivery to the ocean. Flow velocity, salinity, and suspended-sediment concentration were measured for 25 h at three cross sections in the tidal Song Hau distributary of the Mekong River, Vietnam. Two campaigns took place during comparatively high-seasonal and low-seasonal discharge, and estuarine conditions varied dramatically between them. The system transitioned from a tidal river with ephemeral presence of a salt wedge during high flow to a partially mixed estuary during low flow. The changing freshwater input, sediment sources, and estuarine characteristics resulted in seaward sediment export during high flow and landward import during low flow. The Dinh An channel of the Song Hau distributary exported sediment to the coast at a rate of about 1 t s-1 during high flow and imported sediment in a spatially varying manner at approximately 0.3 t s-1 during low flow. Scaling these values results in a yearly Mekong sediment discharge estimate about 65% smaller than a generally accepted estimate of 110 Mt yr-1, although the limited temporal and spatial nature of this study implies a relatively high degree of uncertainty for the new estimate. Fluvial advection of sediment was primarily responsible for the high-flow sediment export. Exchange-flow and tidal processes, including local resuspension, were principally responsible for the low-flow import. The resulting bed-sediment grain size was coarser and more variable during high flow and finer during low, and the residual flow patterns support the maintenance of mid-channel islands. This article was corrected on 7 OCT 2015. See the end of the full text for details.

Fluconazole affects the alkali-metal-cation homeostasis and susceptibility to cationic toxic compounds of Candida glabrata.

PubMed

Elicharova, Hana; Sychrova, Hana

2014-08-01

Candida glabrata is a salt-tolerant and fluconazole (FLC)-resistant yeast species. Here, we analyse the contribution of plasma-membrane alkali-metal-cation exporters, a cation/proton antiporter and a cation ATPase to cation homeostasis and the maintenance of membrane potential (ΔΨ). Using a series of single and double mutants lacking CNH1 and/or ENA1 genes we show that the inability to export potassium and toxic alkali-metal cations leads to a slight hyperpolarization of the plasma membrane of C. glabrata cells; this hyperpolarization drives more cations into the cells and affects cation homeostasis. Surprisingly, a much higher hyperpolarization of C. glabrata plasma membrane was produced by incubating cells with subinhibitory concentrations of FLC. FLC treatment resulted in a substantially increased sensitivity of cells to various cationic drugs and toxic cations that are driven into the cell by negative-inside plasma-membrane potential. The effect of the combination of FLC plus cationic drug treatment was enhanced by the malfunction of alkali-metal-cation transporters that contribute to the regulation of membrane potential and cation homeostasis. In summary, we show that the combination of subinhibitory concentrations of FLC and cationic drugs strongly affects the growth of C. glabrata cells. © 2014 The Authors.

The role of nutricline depth in regulating the ocean carbon cycle.

PubMed

Cermeño, Pedro; Dutkiewicz, Stephanie; Harris, Roger P; Follows, Mick; Schofield, Oscar; Falkowski, Paul G

2008-12-23

Carbon uptake by marine phytoplankton, and its export as organic matter to the ocean interior (i.e., the "biological pump"), lowers the partial pressure of carbon dioxide (pCO(2)) in the upper ocean and facilitates the diffusive drawdown of atmospheric CO(2). Conversely, precipitation of calcium carbonate by marine planktonic calcifiers such as coccolithophorids increases pCO(2) and promotes its outgassing (i.e., the "alkalinity pump"). Over the past approximately 100 million years, these two carbon fluxes have been modulated by the relative abundance of diatoms and coccolithophores, resulting in biological feedback on atmospheric CO(2) and Earth's climate; yet, the processes determining the relative distribution of these two phytoplankton taxa remain poorly understood. We analyzed phytoplankton community composition in the Atlantic Ocean and show that the distribution of diatoms and coccolithophorids is correlated with the nutricline depth, a proxy of nutrient supply to the upper mixed layer of the ocean. Using this analysis in conjunction with a coupled atmosphere-ocean intermediate complexity model, we predict a dramatic reduction in the nutrient supply to the euphotic layer in the coming century as a result of increased thermal stratification. Our findings indicate that, by altering phytoplankton community composition, this causal relationship may lead to a decreased efficiency of the biological pump in sequestering atmospheric CO(2), implying a positive feedback in the climate system. These results provide a mechanistic basis for understanding the connection between upper ocean dynamics, the calcium carbonate-to-organic C production ratio and atmospheric pCO(2) variations on time scales ranging from seasonal cycles to geological transitions.

Evaluating Southern Ocean Carbon Eddy-Pump From Biogeochemical-Argo Floats

NASA Astrophysics Data System (ADS)

Llort, Joan; Langlais, C.; Matear, R.; Moreau, S.; Lenton, A.; Strutton, Peter G.

2018-02-01

The vertical transport of surface water and carbon into ocean's interior, known as subduction, is one of the main mechanisms through which the ocean influences Earth's climate. New instrumental approaches have shown the occurrence of localized and intermittent subduction episodes associated with small-scale ocean circulation features. These studies also revealed the importance of such events for the export of organic matter, the so-called eddy-pump. However, the transient and localized nature of episodic subduction hindered its large-scale evaluation to date. In this work, we present an approach to detect subduction events at the scale of the Southern Ocean using measurements collected by biogeochemical autonomous floats (BGCArgo). We show how subduction events can be automatically identified as anomalies of spiciness and Apparent Oxygen Utilization (AOU) below the mixed layer. Using this methodology over more than 4,000 profiles, we detected 40 subduction events unevenly distributed across the Sothern Ocean. Events were more likely found in hot spots of eddy kinetic energy (EKE), downstream major bathymetric features. Moreover, the bio-optical measurements provided by BGCArgo allowed measuring the amount of Particulate Organic Carbon (POC) being subducted and assessing the contribution of these events to the total downward carbon flux at 100 m (EP100). We estimated that the eddy-pump represents less than 19% to the EP100 in the Southern Ocean, although we observed particularly strong events able to locally duplicate the EP100. This approach provides a novel perspective on where episodic subduction occurs that will be naturally improved as BGCArgo observations continue to increase.

Oceanic acidification affects marine carbon pump and triggers extended marine oxygen holes.

PubMed

Hofmann, Matthias; Schellnhuber, Hans-Joachim

2009-03-03

Rising atmospheric CO(2) levels will not only drive future global mean temperatures toward values unprecedented during the whole Quaternary but will also lead to massive acidification of sea water. This constitutes by itself an anthropogenic planetary-scale perturbation that could significantly modify oceanic biogeochemical fluxes and severely damage marine biota. As a step toward the quantification of such potential impacts, we present here a simulation-model-based assessment of the respective consequences of a business-as-usual fossil-fuel-burning scenario where a total of 4,075 Petagrams of carbon is released into the atmosphere during the current millennium. In our scenario, the atmospheric pCO(2) level peaks at approximately 1,750 microatm in the year 2200 while the sea-surface pH value drops by >0.7 units on global average, inhibiting the growth of marine calcifying organisms. The study focuses on quantifying 3 major concomitant effects. The first one is a significant (climate-stabilizing) negative feedback on rising pCO(2) levels as caused by the attenuation of biogenic calcification. The second one is related to the biological carbon pump. Because mineral ballast, notably CaCO(3), is found to play a dominant role in carrying organic matter through the water column, a reduction of its export fluxes weakens the strength of the biological carbon pump. There is, however, a third effect with severe consequences: Because organic matter is oxidized in shallow waters when mineral-ballast fluxes weaken, oxygen holes (hypoxic zones) start to expand considerably in the oceans in our model world--with potentially harmful impacts on a variety of marine ecosystems.

Discovery of a Siderophore Export System Essential for Virulence of Mycobacterium tuberculosis

PubMed Central

Wells, Ryan M.; Jones, Christopher M.; Xi, Zhaoyong; Speer, Alexander; Danilchanka, Olga; Doornbos, Kathryn S.; Sun, Peibei; Wu, Fangming; Tian, Changlin; Niederweis, Michael

2013-01-01

Iron is an essential nutrient for most bacterial pathogens, but is restricted by the host immune system. Mycobacterium tuberculosis (Mtb) utilizes two classes of small molecules, mycobactins and carboxymycobactins, to capture iron from the human host. Here, we show that an Mtb mutant lacking the mmpS4 and mmpS5 genes did not grow under low iron conditions. A cytoplasmic iron reporter indicated that the double mutant experienced iron starvation even under high-iron conditions. Loss of mmpS4 and mmpS5 did not change uptake of carboxymycobactin by Mtb. Thin layer chromatography showed that the ΔmmpS4/S5 mutant was strongly impaired in biosynthesis and secretion of siderophores. Pull-down experiments with purified proteins demonstrated that MmpS4 binds to a periplasmic loop of the associated transporter protein MmpL4. This interaction was corroborated by genetic experiments. While MmpS5 interacted only with MmpL5, MmpS4 interacted with both MmpL4 and MmpL5. These results identified MmpS4/MmpL4 and MmpS5/MmpL5 as siderophore export systems in Mtb and revealed that the MmpL proteins transport small molecules other than lipids. MmpS4 and MmpS5 resemble periplasmic adapter proteins of tripartite efflux pumps of Gram-negative bacteria, however, they are not only required for export but also for efficient siderophore synthesis. Membrane association of MbtG suggests a link between siderophore synthesis and transport. The structure of the soluble domain of MmpS4 (residues 52–140) was solved by NMR and indicates that mycobacterial MmpS proteins constitute a novel class of transport accessory proteins. The bacterial burden of the mmpS4/S5 deletion mutant in mouse lungs was lower by 10,000-fold and none of the infected mice died within 180 days compared to wild-type Mtb. This is the strongest attenuation observed so far for Mtb mutants lacking genes involved in iron utilization. In conclusion, this study identified the first components of novel siderophore export systems which are essential for virulence of Mtb. PMID:23431276

Multiple Calcium Export Exchangers and Pumps Are a Prominent Feature of Enamel Organ Cells

PubMed Central

Robertson, Sarah Y. T.; Wen, Xin; Yin, Kaifeng; Chen, Junjun; Smith, Charles E.; Paine, Michael L.

2017-01-01

Calcium export is a key function for the enamel organ during all stages of amelogenesis. Expression of a number of ATPase calcium transporting, plasma membrane genes (ATP2B1-4/PMCA1-4), solute carrier SLC8A genes (sodium/calcium exchanger or NCX1-3), and SLC24A gene family members (sodium/potassium/calcium exchanger or NCKX1-6) have been investigated in the developing enamel organ in earlier studies. This paper reviews the calcium export pathways that have been described and adds novel insights to the spatiotemporal expression patterns of PMCA1, PMCA4, and NCKX3 during amelogenesis. New data are presented to show the mRNA expression profiles for the four Atp2b1-4 gene family members (PMCA1-4) in secretory-stage and maturation-stage rat enamel organs. These data are compared to expression profiles for all Slc8a and Slc24a gene family members. PMCA1, PMCA4, and NCKX3 immunolocalization data is also presented. Gene expression profiles quantitated by real time PCR show that: (1) PMCA1, 3, and 4, and NCKX3 are most highly expressed during secretory-stage amelogenesis; (2) NCX1 and 3, and NCKX6 are expressed during secretory and maturation stages; (3) NCKX4 is most highly expressed during maturation-stage amelogenesis; and (4) expression levels of PMCA2, NCX2, NCKX1, NCKX2, and NCKX5 are negligible throughout amelogenesis. In the enamel organ PMCA1 localizes to the basolateral membrane of both secretory and maturation ameloblasts; PMCA4 expression is seen in the basolateral membrane of secretory and maturation ameloblasts, and also cells of the stratum intermedium and papillary layer; while NCKX3 expression is limited to Tomes' processes, and the apical membrane of maturation-stage ameloblasts. These new findings are discussed in the perspective of data already present in the literature, and highlight the multiplicity of calcium export systems in the enamel organ needed to regulate biomineralization. PMID:28588505

Climate Change Response of Ocean Net Primary Production (NPP) and Export Production (EP) Regulated by Stratification Increases in The CMIP5 models

NASA Astrophysics Data System (ADS)

Fu, W.; Randerson, J. T.; Moore, J. K.

2014-12-01

Ocean warming due to rising atmospheric CO2 has increasing impacts on ocean ecosystems by modifying the ecophysiology and distribution of marine organisms, and by altering ocean circulation and stratification. We explore ocean NPP and EP changes at the global scale with simulations performed in the framework of the fifth Coupled Model Inter-comparison Project (CMIP5). Global NPP and EP are reduced considerably by the end of the century for the representative concentration pathway (RCP) 8.5 scenario, although models differ in their significantly in their direct temperature impacts on production and remineralization. The Earth system models used here project similar NPP trends albeit the magnitudes vary substantially. In general, projected changes in the 2090s for NPP range between -2.3 to -16.2% while export production reach -7 to -18% relative to 1990s. This is accompanied by increased stratification by 17-30%. Results indicate that globally reduced NPP is closely related to increased ocean stratification (R2=0.78). This is especially the case for global export production, that seems to be mostly controlled by the increased stratification (R2=0.95). We also identify phytoplankton community impacts on these patterns, that vary across the models. The negative response of NPP to climate change may be through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. There are large disagreements among the CMIP5 models in terms of simulated nutrient and oxygen concentrations for the 1990s, and their trends over time with climate change. In addition, potentially important marine biogeochemical feedbacks on the climate system were not well represented in the CMIP5 models, including important feedbacks with aerosol deposition and the marine iron cycle, and feedbacks involving the oxygen minimum zones and the marine nitrogen cycle. Thus, these substantial reductions in primary productivity and export production over the 21st century simulated under the RCP 8.5 scenario were likely conservative estimates, and may need to be revised as marine biogeochemistry in Earth System Models (ESMs) continues to be developed.

Water in urban planning, Salt Creek Basin, Illinois water management as related to alternative land-use practices

USGS Publications Warehouse

Spieker, Andrew Maute

1970-01-01

Water management can be an integral part of urban comprehensive planning in a large metropolitan area. Water both imposes constraints on land use and offers opportunities for coordinated land and water management. Salt Creek basin in Cook and Du Page Counties of the Chicago metropolitan area is typical of rapidly developing suburban areas and has been selected to illustrate some of these constraints and opportunities and to suggest the effects of alternative solutions. The present study concentrates on the related problems of ground-water recharge, water quality, management of flood plains, and flood-control measures. Salt Creek basin has a drainage area of 150 square miles. It is in flat to. gently rolling terrain, underlain by glacial drift as much as 200 feet thick which covers a dolomite aquifer. In 1964, the population of the basin was about 400,000, and 40 percent of the land was in urban development. The population is expected to number 550,000 to 650,000 by 1990, and most of the land will be taken by urban development. Salt Creek is a sluggish stream, typical of small drainage channels in the headwaters area of northeastern Illinois. Low flows of 15 to 25 cubic feet per second in the lower part of the basin consist largely of sewage effluent. Nearly all the public water supplies in the basin depend on ground water. Of the total pumpage of 27.5 million gallons per day, 17.5 million gallons per day is pumped from the deep (Cambrian-Ordovician) aquifers and 10 million gallons per day is pumped from the shallow (Silurian dolomite and glacial drift) aquifers. The potential yield of the shallow aquifers, particularly glacial drift in the northern part of the basin, far exceeds present use. The largest concentration of pumpage from the shallow ,aquifers is in the Hinsdale-La Grange area. Salt Creek serves as an important source of recharge to these supplies, particularly just east of Hinsdale. The entire reach of Salt Creek south and east of Elmhurst can be regarded as an area of potential recharge to the shallow aquifers. Preservation of the effectiveness of these potential recharge areas should be considered in land-use planning. Salt Creek is polluted in times of both low and high flow. Most communities in the basin in Du Page County discharge their treated sewage into the creek, whereas those in Cook County transfer their sewage to plants of the Metropolitan Sanitary District outside the basin. During periods of high runoff, combined storm runoff and overflow from sanitary sewers enter the creek. Such polluted water detracts from the stream's esthetic and recreational potential and poses a threat to ground-water supplies owing to induced recharge of polluted water to shallow aquifers. Alternative approaches .to the pollution problem include improvement of the degree of sewage treatment, detention and treatment of storm runoff, dilution of sewage through flow augmentation, or transfer of sewage from the basin to a central treatment plant. To result in an enhanced environment, the streambed would have to be cleansed of accumulated sludge deposits. The overbank flooding in Salt Creek basin every 2 to 3 years presents problems because of encroachments and developments on the flood plains. Flood plains in an urban area can be managed by identifying them, by recognizing that either their natural storage capacity or equivalent artificial capacity is needed to accommodate floods, and by planning land use accordingly. Examples of effective floodplain management include (1) preservation of greenbelts or regional parks along stream courses, (2) use of flood plains for recreation, parking lots. or other low-intensity uses, (3) use of flood-proofed commercial buildings, and (4) provision for compensatory storage to replace natural storage capacity. Results of poor flood-plain management include uncontrolled residential development and encroachment by fill into natural storage areas where no compensatory storage has been

Late summer particulate organic carbon export and twilight zone remineralisation in the Atlantic sector of the Southern Ocean

NASA Astrophysics Data System (ADS)

Planchon, F.; Cavagna, A.-J.; Cardinal, D.; André, L.; Dehairs, F.

2012-03-01

During the Bonus-GoodHope (BGH) expedition (Jan-Mar 2008) we studied the water column distribution of total 234Th and biogenic particulate Ba (Baxs) in the Atlantic sector of the Southern Ocean. The objective was to assess the export flux of particulate organic carbon (POC) from the surface to the mesopelagic twilight zone along a section between the Cape Basin and Weddell Gyre. Export production of POC was estimated from steady state and non steady state export fluxes of 234Th which were converted into POC fluxes, using the POC/234Th ratio of large (>53 μm) suspended particles, collected via in-situ pumps. Deficits in 234Th activities were observed at all stations from the surface to the bottom of the mixed-layer. 234Th export fluxes from the upper 100 m ranged from 496 ± 57 dpm m-2 d-1 to 1195 ± 120 dpm m-2 d-1 for the steady state model and from 149 ± 18 dpm m-2 d-1 to 1217 ± 146 dpm m-2 d-1 for the non steady state model calculated for a time window of 15 to 22 days preceding the timing of the present cruise. The POC/234Thp ratio of large, potentially sinking particles (>53 μm), was observed to increase with latitude, from 1.9 ± 0.2 μmol dpm-1 and 1.7 ± 0.3 μmol dpm-1 in the Subtropical Zone (STZ) and Subantarctic Zone (SAZ), respectively, to 3.0 ± 0.2 μmol dpm-1 in the Polar Front Zone (PFZ), 4.8 ± 1.9 μmol dpm-1 at the Southern Antarctic Circumpolar Current Front (SACCF) to 4.1 ± 1.7 μmol dpm-1 in the northern Weddell Gyre, in line with an increasing contribution of larger cell diatoms. Steady state and non steady state POC export from the upper 100 m ranged from 0.9 ± 0.2 mmolC m-2 d-1 to 5.1 ± 2.1 mmolC m-2 d-1 and from 0.3 ± 0.0 mmolC m-2 d-1 to 4.9 ± 3.2 mmolC m-2 d-1, respectively. From the SAZ to the SACCF, non steady state POC export production represented only 15 to 54 % of the steady state POC flux, suggesting that the intensity of export had decreased over time partly due to the fact that regenerated-production based communities of small-sized phytoplankton became predominant. In contrast, for the HNLC area south of the SACCF, we found an excellent agreement between the two modeling approaches indicating that surface POC export remained rather constant there. Estimated POC export represented between 6 to 54 % of the potential export as represented by new production, indicating that export efficiency was particularly low throughout the studied area, except close to the SACCF. Below the export layer, in the mesopelagic zone, 234Th activities generally reached equilibrium with 238U, but sometimes were in large excess relative to 238U (234Th/238U ratio>1.1), reflecting intense remineralisation/disaggregation of 234Th-bearing particles. The accumulation of excess 234Th in the 100-600 m depth interval ranged from 458 ± 55 dpm m-2 d-1 to 3068 ± 368 dpm m-2 d-1. Using POC to 234Th ratio of sinking particles, we converted this 234Th flux into a POC remineralisation flux, which ranged between 0.9 to 9.2 mmolC m-2 d-1. Mesopelagic remineralisation was also evidenced by Baxs inventories which are related to bacterial degradation of sinking material and offer a means to quantify the flux of respired C. Highest biogenic particulate Ba (Baxs) contents were generally observed in the 200-400 m depth interval with values reaching up to >1000 pM in the northern PFZ. Depth weighted average mesopelagic Baxs (meso-Baxs) was high in the PFZ and low in the northernmost (STZ-SAZ) and the southernmost (SACCF-AZ-WG) parts of the BGH section; conversion into respired C flux yielded a range of -0.23 to 6.4 mmolC m-2 d-1. Excluding two outliers, we found a significant positive correlation for mesopelagic waters between POC remineralisation estimated from meso-Baxs and from 234Th excess (R2 = 0.73). Our results indicate that POC export production in this area of the Southern Ocean was strongly attenuated in the mesopelagic waters due to remineralisation, a process which thus appears to strongly impact on longer term bathypelagic zone sequestration of POC.

Selective production of sealed plasma membrane vesicles from red beet (Beta vulgaris L.) storage tissue.

PubMed

Giannini, J L; Gildensoph, L H; Briskin, D P

1987-05-01

Modification of our previous procedure for the isolation of microsomal membrane vesicles from red beet (Beta vulgaris L.) storage tissue allowed the recovery of sealed membrane vesicles displaying proton transport activity sensitive to both nitrate and orthovanadate. In the absence of a high salt concentration in the homogenization medium, contributions of nitrate-sensitive (tonoplast) and vanadate-sensitive (plasma membrane) proton transport were roughly equal. The addition of 0.25 M KCl to the homogenization medium increased the relative amount of nitrate-inhibited proton transport activity while the addition of 0.25 M KI resulted in proton pumping vesicles displaying inhibition by vanadate but stimulation by nitrate. These effects appeared to result from selective sealing of either plasma membrane or tonoplast membrane vesicles during homogenization in the presence of the two salts. Following centrifugation on linear sucrose gradients it was shown that the nitrate-sensitive, proton-transporting vesicles banded at low density and comigrated with nitrate-sensitive ATPase activity while the vanadate-sensitive, proton-transporting vesicles banded at a much higher density and comigrated with vanadate-sensitive ATPase. The properties of the vanadate-sensitive proton pumping vesicles were further characterized in microsomal membrane fractions produced by homogenization in the presence of 0.25 M KI and centrifugation on discontinuous sucrose density gradients. Proton transport was substrate specific for ATP, displayed a sharp pH optimum at 6.5, and was insensitive to azide but inhibited by N'-N-dicyclohexylcarbodiimide, diethylstilbestrol, and fluoride. The Km of proton transport for Mg:ATP was 0.67 mM and the K0.5 for vanadate inhibition was at about 50 microM. These properties are identical to those displayed by the plasma membrane ATPase and confirm a plasma membrane origin for the vesicles.

Polar-solvent-free colloidal synthesis of highly luminescent alkylammonium lead halide perovskite nanocrystals

NASA Astrophysics Data System (ADS)

Vybornyi, Oleh; Yakunin, Sergii; Kovalenko, Maksym V.

2016-03-01

A novel synthesis of hybrid organic-inorganic lead halide perovskite nanocrystals (CH3NH3PbX3, X = Br or I) that does not involve the use of dimethylformamide or other polar solvents is presented. The reaction between methylamine and PbX2 salts is conducted in a high-boiling nonpolar solvent (1-octadecene) in the presence of oleylamine and oleic acid as coordinating ligands. The resulting nanocrystals are characterized by high photoluminescence quantum efficiencies of 15-50%, outstanding phase purity and tunable shapes (nanocubes, nanowires, and nanoplatelets). Nanoplatelets spontaneously assemble into micrometer-length wires by face-to-face stacking. In addition, we demonstrate amplified spontaneous emission from thin films of green-emitting CH3NH3PbBr3 nanowires with low pumping thresholds of 3 μJ cm-2.A novel synthesis of hybrid organic-inorganic lead halide perovskite nanocrystals (CH3NH3PbX3, X = Br or I) that does not involve the use of dimethylformamide or other polar solvents is presented. The reaction between methylamine and PbX2 salts is conducted in a high-boiling nonpolar solvent (1-octadecene) in the presence of oleylamine and oleic acid as coordinating ligands. The resulting nanocrystals are characterized by high photoluminescence quantum efficiencies of 15-50%, outstanding phase purity and tunable shapes (nanocubes, nanowires, and nanoplatelets). Nanoplatelets spontaneously assemble into micrometer-length wires by face-to-face stacking. In addition, we demonstrate amplified spontaneous emission from thin films of green-emitting CH3NH3PbBr3 nanowires with low pumping thresholds of 3 μJ cm-2. Electronic supplementary information (ESI) available: Materials and methods, additional figures. See DOI: 10.1039/c5nr06890h

Embedded Sensors and Controls to Improve Component Performance and Reliability -- Loop-scale Testbed Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melin, Alexander M.; Kisner, Roger A.

2016-09-01

Embedded instrumentation and control systems that can operate in extreme environments are challenging to design and operate. Extreme environments limit the options for sensors and actuators and degrade their performance. Because sensors and actuators are necessary for feedback control, these limitations mean that designing embedded instrumentation and control systems for the challenging environments of nuclear reactors requires advanced technical solutions that are not available commercially. This report details the development of testbed that will be used for cross-cutting embedded instrumentation and control research for nuclear power applications. This research is funded by the Department of Energy's Nuclear Energy Enabling Technologymore » program's Advanced Sensors and Instrumentation topic. The design goal of the loop-scale testbed is to build a low temperature pump that utilizes magnetic bearing that will be incorporated into a water loop to test control system performance and self-sensing techniques. Specifically, this testbed will be used to analyze control system performance in response to nonlinear and cross-coupling fluid effects between the shaft axes of motion, rotordynamics and gyroscopic effects, and impeller disturbances. This testbed will also be used to characterize the performance losses when using self-sensing position measurement techniques. Active magnetic bearings are a technology that can reduce failures and maintenance costs in nuclear power plants. They are particularly relevant to liquid salt reactors that operate at high temperatures (700 C). Pumps used in the extreme environment of liquid salt reactors provide many engineering challenges that can be overcome with magnetic bearings and their associated embedded instrumentation and control. This report will give details of the mechanical design and electromagnetic design of the loop-scale embedded instrumentation and control testbed.« less

Water exit pathways and proton pumping mechanism in B-type cytochrome c oxidase from molecular dynamics simulations.

PubMed

Yang, Longhua; Skjevik, Åge A; Han Du, Wen-Ge; Noodleman, Louis; Walker, Ross C; Götz, Andreas W

2016-09-01

Cytochrome c oxidase (CcO) is a vital enzyme that catalyzes the reduction of molecular oxygen to water and pumps protons across mitochondrial and bacterial membranes. While proton uptake channels as well as water exit channels have been identified for A-type CcOs, the means by which water and protons exit B-type CcOs remain unclear. In this work, we investigate potential mechanisms for proton transport above the dinuclear center (DNC) in ba3-type CcO of Thermus thermophilus. Using long-time scale, all-atom molecular dynamics (MD) simulations for several relevant protonation states, we identify a potential mechanism for proton transport that involves propionate A of the active site heme a3 and residues Asp372, His376 and Glu126(II), with residue His376 acting as the proton-loading site. The proposed proton transport process involves a rotation of residue His376 and is in line with experimental findings. We also demonstrate how the strength of the salt bridge between residues Arg225 and Asp287 depends on the protonation state and that this salt bridge is unlikely to act as a simple electrostatic gate that prevents proton backflow. We identify two water exit pathways that connect the water pool above the DNC to the outer P-side of the membrane, which can potentially also act as proton exit transport pathways. Importantly, these water exit pathways can be blocked by narrowing the entrance channel between residues Gln151(II) and Arg449/Arg450 or by obstructing the entrance through a conformational change of residue Tyr136, respectively, both of which seem to be affected by protonation of residue His376. Copyright © 2016 Elsevier B.V. All rights reserved.

The pathway by which the yeast protein kinase Snf1p controls acquisition of sodium tolerance is different from that mediating glucose regulation.

PubMed

Ye, Tian; Elbing, Karin; Hohmann, Stefan

2008-09-01

It recently became apparent that the highly conserved Snf1p protein kinase plays roles in controlling different cellular processes in the yeast Saccharomyces cerevisiae, in addition to its well-known function in glucose repression/derepression. We have previously reported that Snf1p together with Gis4p controls ion homeostasis by regulating expression of ENA1, which encodes the Ena1p Na(+) extrusion system. In this study we found that Snf1p is rapidly phosphorylated when cells are exposed to NaCl and this phosphorylation is required for the role of Snf1p in Na(+) tolerance. In contrast to activation by low glucose levels, the salt-induced phosphorylation of Snf1p promoted neither phosphorylation nor nuclear export of the Mig1p repressor. The mechanism that prevents Mig1p phosphorylation by active Snf1p under salt stress does not involve either hexokinase PII or the Gis4p regulator. Instead, Snf1p may mediate upregulation of ENA1 expression via the repressor Nrg1p. Activation of Snf1p in response to glucose depletion requires any of the three upstream protein kinases Sak1p, Tos3p and Elm1p, with Sak1p playing the most prominent role. The same upstream kinases were required for salt-induced Snf1p phosphorylation, and also under these conditions Sak1p played the most prominent role. Unexpectedly, however, it appears that Elm1p plays a dual role in acquisition of salt tolerance by activating Snf1p and in a presently unknown parallel pathway. Together, these results indicate that under salt stress Snf1p takes part in a different pathway from that during glucose depletion and this role is performed together as well as in parallel with its upstream kinase Elm1p. Snf1p appears to be part of a wider functional network than previously anticipated and the full complexity of this network remains to be elucidated.

Impact of Pretreatment and Drying Methods on Quality Attributes of Onion Shreds

PubMed Central

Sahoo, Nihar R.; Pal, Uma S.; Sahoo, Dipika

2015-01-01

Summary Experiments were conducted on dry untreated onion shreds (2 mm thickness) or treated with salt (5% solution) and potassium metabisulphite (0.5% solution) in convective drier at 50 °C ((46±4) % relative humidity (RH)), 55 °C ((35±4) % RH), 60 °C ((28±4) % RH) and 65 °C ((20±4) % RH), heat pump-assisted convective drier at 35 °C ((32±2) % RH), 40 °C ((26±2) % RH), 45 °C ((19±2) % RH) and 50 °C ((15±2) % RH) and microwave-assisted convective drier at four microwave power levels, i.e. 120, 240, 360 and 480 W. The quality parameters of the dried onion shreds, namely rehydration ratio, colour difference, pyruvic and ascorbic acid contents and sensory scores were evaluated. The quality of dehydrated onion shreds was observed to be comparatively better when treated in heat pump drier at 50 °C, followed by that in microwave-assisted convective drier at 240 W and 50 °C, and last in convective drier at 60 °C. The onion shreds pretreated with potassium metabisulphite retained better colour of the dried product irrespective of drying methods. Therefore, heat pump drying may be recommended as one of the best drying methods for onion shreds, because it maintains the final product quality, which has practical importance for the food industry. PMID:27904332

Interaction of Sound with Sound by Novel Mechanisms: Ultrasonic Four-Wave Mixing Mediated by a Suspension and Ultrasonic Three-Wave Mixing at a Free Surface

NASA Astrophysics Data System (ADS)

Simpson, Harry Jay

Two mechanisms of sound interacting with sound are experimentally and theoretically investigated. Ultrasonic four-wave mixing in a dilute particle suspension, analogous to optical four-wave mixing in photorefractive materials, involves the interaction of three ultrasonic wavefields that produces a fourth scattered wavefield. The experimental configuration consists of two ultrasonic (800 kHz) pump waves that are used to produce a grating in a suspension of 25 μm diameter polymer particles in salt water. The pump waves are counter-propagating, which form a standing wavefield in the suspension and the less compressible particles are attracted to the pressure nodes in response to the time averaged radiation pressure. A higher frequency (2-10 MHz) ultrasonic wavefield is used to probe the resulting grating. The ultrasonic Bragg scattering is then measured. The scattering depends strongly on the response to the pump wave and is an unusual class of acoustical nonlinearity. Investigation of very small amplitude gratings are done by studying the temporal response of the Bragg scattering to a sudden turn on of a moderate amplitude pump wavefield in a previously homogeneous particle suspension. The Bragg scattering has been verified experimentally and is modeled for early-time grating formations using a sinusoidal grating. The larger amplitude gratings are studied in equilibrium and are modeled using an Epstein layer approximation. Ultrasonic three-wave mixing at a free surface involves the interaction of a high amplitude 400 kHz plane wavefield incident at 33^circ on a water-air interface with a normally incident high frequency (4.6 MHz) focused wavefield. The 400 kHz "pump" wavefield reflects from the surface and produces an oscillating surface displacement that forms a local traveling phase grating. Simultaneously the 4.6 MHz "probe" wavefield is reflected from the free surface. The grating scatters the focused probe wavefield and produces (or contributes to) spatially and Doppler shifted foci relative to the main focus.

Interaction of sound with sound by novel mechanisms: Ultrasonic four-wave mixing mediated by a suspension and ultrasonic three-wave mixing at a free surface

NASA Astrophysics Data System (ADS)

Simpson, Harry Jay

Two mechanisms of sound interacting with sound are experimentally and theoretically investigated. Ultrasonic four-wave mixing in a dilute particle suspension, analogous to optical four-wave mixing in photorefractive materials, involves the interaction of three ultrasonic wavefields that produces a fourth scattered wavefield. The experimental configuration consists of two ultrasonic (800 kHz) pump waves that are used to produce a grating in a suspension of 25 micron diameter polymer particles in salt water. The pump waves are counter-propagating, which form a standing wavefield in the suspension and the less compressible particles are attracted to the pressure nodes in response to the time averaged radiation pressure. A higher frequency (2 to 10 MHz) ultrasonic wavefield is used to probe the resulting grating. The ultrasonic Bragg scattering is then measured. The scattering depends strongly on the response to the pump wave and is an unusual class of acoustical nonlinearity. Investigation of very small amplitude gratings are done by studying the temporal response of the Bragg scattering to a sudden turn on of a moderate amplitude pump wavefield in a previously homogeneous particle suspension. The Bragg scattering has been verified experimentally and is modeled for early-time grating formations using a sinusoidal grating. The larger amplitude gratings are studied in equilibrium and are modeled using an Epstein layer approximation. Ultrasonic three-wave mixing at a free surface involves the interaction of a high amplitude 400 kHz plane wavefield incident at 33 degrees on a water-air interface with a normally incident high frequency (4.6 MHz) focused wavefield. The 400 kHz 'pump' wavefield reflects from the surface and produces an oscillating surface displacement that forms a local traveling phase grating. Simultaneously the 4.6 MHz 'probe' wavefield is reflected from the free surface. The grating scatters the focused probe wavefield and produces (or contributes to) spatially and Doppler shifted foci relative to the main focus.

2,2'-Dihydroxychalcone, a glutathione transferase inhibitor, sensitises human colon adenocarcinoma cells to chlorambucil and melphalan, but not to actinomycin D.

PubMed

Goh, Kenneth; Chen, Yufan; Zheng, Lin; Ong, Laichun; Jin, Yi; Chow, Pierce; Zhang, Kai

2008-01-01

2,2'-Dihydroxychalcone (2,2'DHC) is a potent inhibitor of glutathione S-transferases (GSTs). Pre-treatment of human colon cancer cells by a non-toxic concentration of this GST inhibitor significantly sensitised cancer cells to chlorambucil and melphalan, which are substrates of glutathione (GSH) conjugation. However, sensitisation to actinomycin D, which has not been shown to be detoxified by GSH-related mechanisms, was not observed. These results further confirm the contribution of GSH-related mechanisms to drug resistance by increased detoxification of drugs. 2,2'DHC inhibited GST activity and the transport of GSH conjugates by cancer cells. Its combined effects on GST and glutathione conjugate export (GS-X) pump may provide more potent sensitisation of cancer cells to chemotherapeutic drugs.

Calculation of area and volume for the south part of Great Salt Lake, Utah

USGS Publications Warehouse

Baskin, Robert L.

2005-01-01

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Wildlife Resources, collected bathymetric data for the south part of Great Salt Lake during 2002-04 using a single-beam, high-definition fathometer and real-time differential global positioning system. About 7.6 million depth measurements were collected along more than 930 miles (1,690 kilometers) of survey transects. Sound-velocity profiles were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed with commercial hydrographic software and exported into geographic information system (GIS) software for mapping and calculation of area and volume. Area and volume calculations show a maximum area of about 508,000 acres (2,056 square kilometers) and a maximum volume of about 9,257,000 acre-feet (11.42 cubic kilometers) at a water-surface altitude of 4,200 feet (1,280 meters). Minimum water-surface altitude of the south part of Great Salt Lake is just below 4,167 feet (1,279 meters) in the area just south of the Union Pacific railroad causeway halfway between Promontory Point and the western edge of the lake. At this altitude, and continuing up to about 4,176 feet (1,279 meters), the south part of the lake is separated into two areas by a ridge extending from Promontory Point to Hat Island. Calculations for area and volume are based on a low altitude of 4,167 feet (1,279 meters) to a high altitude of 4,200 feet (1,280 meters).

Decreased capacity for sodium export out of Arabidopsis chloroplasts impairs salt tolerance, photosynthesis and plant performance.

PubMed

Müller, Maria; Kunz, Hans-Henning; Schroeder, Julian I; Kemp, Grant; Young, Howard S; Neuhaus, H Ekkehard

2014-05-01

Salt stress is a widespread phenomenon, limiting plant performance in large areas around the world. Although various types of plant sodium/proton antiporters have been characterized, the physiological function of NHD1 from Arabidopsis thaliana has not been elucidated in detail so far. Here we report that the NHD1-GFP fusion protein localizes to the chloroplast envelope. Heterologous expression of AtNHD1 was sufficient to complement a salt-sensitive Escherichia coli mutant lacking its endogenous sodium/proton exchangers. Transport competence of NHD1 was confirmed using recombinant, highly purified carrier protein reconstituted into proteoliposomes, proving Na(+) /H(+) antiport. In planta NHD1 expression was found to be highest in mature and senescent leaves but was not induced by sodium chloride application. When compared to wild-type controls, nhd1 T-DNA insertion mutants showed decreased biomasses and lower chlorophyll levels after sodium feeding. Interestingly, if grown on sand and supplemented with high sodium chloride, nhd1 mutants exhibited leaf tissue Na(+) levels similar to those of wild-type plants, but the Na(+) content of chloroplasts increased significantly. These high sodium levels in mutant chloroplasts resulted in markedly impaired photosynthetic performance as revealed by a lower quantum yield of photosystem II and increased non-photochemical quenching. Moreover, high Na(+) levels might hamper activity of the plastidic bile acid/sodium symporter family protein 2 (BASS2). The resulting pyruvate deficiency might cause the observed decreased phenylalanine levels in the nhd1 mutants due to lack of precursors. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

The Hyperspectral Absorption Sensor - Advantages and challenges of continuous, in situ absorption coefficient measurements

NASA Astrophysics Data System (ADS)

Wollschläger, J.; Röttgers, R.; Petersen, W.; Zielinski, O.

2016-12-01

A free-water mass balance-based study was conducted to address the rate of metabolism and net carbon exchange for the tidal wetland and estuarine portion of the coastal ocean and the uncertainties associated with this approach were assessed. Open water diurnal O2 and dissolved inorganic carbon (DIC) were measured seasonally in a salt marsh-estuary in Georgia, U.S.A. with a focus on the marsh-estuary linkage associated with tidal flooding. We observed that the overall estuarine system was a net source of CO2 to the atmosphere and coastal ocean and a net sink for oceanic and atmospheric O2. Rates of metabolism were extremely high, with respiration (43 mol m-2 yr-1) greatly exceeding gross primary production (28 mol m-2 yr-1), such that the overall system was net heterotrophic. Metabolism measured with DIC were higher than with O2, which we attribute to high rates of anaerobic respiration and reduced sulfur storage in salt marsh sediments, and we assume substantial levels of anoxygenic photosynthesis. We found gas exchange from a flooded marsh is substantial, accounting for about 28% of total O2 and CO2 air-water exchange. A significant percentage of the overall estuarine aquatic metabolism is attributable to metabolism of marsh organisms during inundation. Our study suggests not rely on oceanographic stoichiometry to convert from O2to C based measurements when constructing C balances for the coastal ocean. We also suggest eddy covariance measurements of salt marsh net ecosystem exchange underestimate net ecosystem production as they do not account for lateral DIC exchange associated with marsh tidal inundation. With the increase of global temperature and sea level rise, salt marshes are likely to export more inorganic carbon to the atmosphere and the coastal ocean due to the decrease of solubility, the increase of aquatic and benthic metabolic activities and the longer marsh inundation.

Inorganic Carbon and Oxygen Dynamics in a Marsh-dominated Estuary

NASA Astrophysics Data System (ADS)

Wang, S. R.; Di Iorio, D.; Cai, W. J.; Hopkinson, C.

2017-12-01

A free-water mass balance-based study was conducted to address the rate of metabolism and net carbon exchange for the tidal wetland and estuarine portion of the coastal ocean and the uncertainties associated with this approach were assessed. Open water diurnal O2 and dissolved inorganic carbon (DIC) were measured seasonally in a salt marsh-estuary in Georgia, U.S.A. with a focus on the marsh-estuary linkage associated with tidal flooding. We observed that the overall estuarine system was a net source of CO2 to the atmosphere and coastal ocean and a net sink for oceanic and atmospheric O2. Rates of metabolism were extremely high, with respiration (43 mol m-2 yr-1) greatly exceeding gross primary production (28 mol m-2 yr-1), such that the overall system was net heterotrophic. Metabolism measured with DIC were higher than with O2, which we attribute to high rates of anaerobic respiration and reduced sulfur storage in salt marsh sediments, and we assume substantial levels of anoxygenic photosynthesis. We found gas exchange from a flooded marsh is substantial, accounting for about 28% of total O2 and CO2 air-water exchange. A significant percentage of the overall estuarine aquatic metabolism is attributable to metabolism of marsh organisms during inundation. Our study suggests not rely on oceanographic stoichiometry to convert from O2to C based measurements when constructing C balances for the coastal ocean. We also suggest eddy covariance measurements of salt marsh net ecosystem exchange underestimate net ecosystem production as they do not account for lateral DIC exchange associated with marsh tidal inundation. With the increase of global temperature and sea level rise, salt marshes are likely to export more inorganic carbon to the atmosphere and the coastal ocean due to the decrease of solubility, the increase of aquatic and benthic metabolic activities and the longer marsh inundation.

Coastal aquifer groundwater dynamics and salt intrusion: Monitoring system of river Neretva delta

NASA Astrophysics Data System (ADS)

Srzić, Veljko; Vranješ, Mijo; Deković, Jure; Romić, Davor; Zovko, Monika; Milin, Marin

2017-04-01

River Neretva delta is located in southern part of Croatia and creates a complex surface- groundwater system influenced by tidal forces characteristic for Adriatic Sea and river Neretva whose discharge varies from 70 - 2700 m3/s over the year. From agricultural point of view, area is used widely for fruit production which implies existence and functionality of complex drainage system consisted of a net of lateral channels and pumping station plants with the capacity of app. 25 m3/s. Area of interest covers app 3500 ha and is bounded by river Neretva from North and Adriatic sea from West. Southern and eastern boundaries are dominantly karstic hills. Lover aquifer is confined with app depth of 65 m, made of fine gravel. Aquitard is a 15 m height layer of clay. Upper aquifer in unconfined with depth of app 10-20 m. Inside the area of interest there are 8 wells installed (each aquifer 4) measuring piezometric head on hourly/daily temporal scale. Sea level measurements are also made capturing for long term tidal oscillations. Discharge measurements are made few km downstream from hydropower plant Mostar (Bosnia and Herzegovina), while three meteorological stations for rainfall measurements are located at the area boundaries. Salt water concentration, pH and resistivity values have been measured locally, app 6 times per year for last 10 years. Results imply confined aquifer is dominantly influenced by the sea level while tidal effects are noticed 9 km upstream the river Neretva with delay of 9-12 minutes compared to sea level. Salt water cline inside the river is related to tidal effects and river discharge, with potential presence at distances of more than 15 km upstream from the sea. Salt water intrusion dominantly occurs through confined aquifer while vertical transport of salt is supposed to be enhanced by the effects of drainage system.

Halorhodopsin pumps Cl– and bacteriorhodopsin pumps protons by a common mechanism that uses conserved electrostatic interactions

PubMed Central

Gunner, M. R.

2014-01-01

Key mutations differentiate the functions of homologous proteins. One example compares the inward ion pump halorhodopsin (HR) and the outward proton pump bacteriorhodopsin (BR). Of the nine essential buried ionizable residues in BR, six are conserved in HR. However, HR changes three BR acids, D85 in a central cluster of ionizable residues, D96, nearer the intracellular, and E204, nearer the extracellular side of the membrane to the small, neutral amino acids T111, V122, and T230, respectively. In BR, acidic amino acids are stationary anions whose proton affinity is modulated by conformational changes, establishing a sequence of directed binding and release of protons. Multiconformation continuum electrostatics calculations of chloride affinity and residue protonation show that, in reaction intermediates where an acid is ionized in BR, a Cl– is bound to HR in a position near the deleted acid. In the HR ground state, Cl– binds tightly to the central cluster T111 site and weakly to the extracellular T230 site, recovering the charges on ionized BR-D85 and neutral E204 in BR. Imposing key conformational changes from the BR M intermediate into the HR structure results in the loss of Cl– from the central T111 site and the tight binding of Cl– to the extracellular T230 site, mirroring the changes that protonate BR-D85 and ionize E204 in BR. The use of a mobile chloride in place of D85 and E204 makes HR more susceptible to the environmental pH and salt concentrations than BR. These studies shed light on how ion transfer mechanisms are controlled through the interplay of protein and ion electrostatics. PMID:25362051

The Role of Na,k-Atpase α Subunit Serine 775 and Glutamate 779 in Determining the Extracellular K+And Membrane Potential–Dependent Properties of the Na,k -Pump

PubMed Central

Peluffo, R. Daniel; Argüello, José M.; Berlin, Joshua R.

2000-01-01

The roles of Ser775 and Glu779, two amino acids in the putative fifth transmembrane segment of the Na,K -ATPase α subunit, in determining the voltage and extracellular K + (K + o) dependence of enzyme-mediated ion transport, were examined in this study. HeLa cells expressing the α1 subunit of sheep Na,K -ATPase were voltage clamped via patch electrodes containing solutions with 115 mM Na+ (37°C). Na,K -pump current produced by the ouabain-resistant control enzyme (RD), containing amino acid substitutions Gln111Arg and Asn122Asp, displayed a membrane potential and K + o dependence similar to wild-type Na,K -ATPase during superfusion with 0 and 148 mM Na+-containing salt solutions. Additional substitution of alanine at Ser775 or Glu779 produced 155- and 15-fold increases, respectively, in the K + o concentration that half-maximally activated Na,K -pump current at 0 mV in extracellular Na+-free solutions. However, the voltage dependence of Na,K -pump current was unchanged in RD and alanine-substituted enzymes. Thus, large changes in apparent K + o affinity could be produced by mutations in the fifth transmembrane segment of the Na,K -ATPase with little effect on voltage-dependent properties of K + transport. One interpretation of these results is that protein structures responsible for the kinetics of K + o binding and/or occlusion may be distinct, at least in part, from those that are responsible for the voltage dependence of K + o binding to the Na,K -ATPase. PMID:10871639

Trace elements determination in seawater by ICP-MS with on-line pre-concentration on a Chelex-100 column using a ‘standard’ instrument setup.

PubMed Central

Søndergaard, Jens; Asmund, Gert; Larsen, Martin M.

2015-01-01

Trace element determination in seawater is analytically challenging due to the typically very low concentrations of the trace elements and the potential interference of the salt matrix. A common way to address the challenge is to pre-concentrate the trace elements on a chelating resin, then rinse the matrix elements from the resin and subsequently elute and detect the trace elements using inductively coupled plasma mass spectrometry (ICP-MS). This technique typically involves time-consuming pre-treatment of the samples for ‘off-line’ analyses or complicated sample introduction systems involving several pumps and valves for ‘on-line’ analyses. As an alternative, the following method offers a simple method for ‘on-line’ analyses of seawater by ICP-MS. As opposed to previous methods, excess seawater was pumped through the nebulizer of the ICP-MS during the pre-concentration step but the gas flow was adjusted so that the seawater was pumped out as waste without being sprayed into the instrument. Advantages of the method include: • Simple and convenient analyses of seawater requiring no changes to the ‘standard’ sample introduction system except from a resin-filled micro-column connected to the sample tube. The ‘standard’ sample introduction system refers to that used for routine digest-solution analyses of biota and sediment by ICP-MS using only one peristaltic pump; and • Accurate determination of the elements V, Mn, Co, Ni, Cu, Zn, Cd and Pb in a range of different seawater matrices verified by participation in 6 successive rounds of the international laboratory intercalibration program QUASIMEME. PMID:26258050

Ghaba salt basin province and Fahud salt basin province, Oman; geological overview and total petroleum systems

USGS Publications Warehouse

Pollastro, R.M.

1999-01-01

Three Total Petroleum Systems each consisting of one assessment unit have been identified in the Ghaba and Fahud Salt Basin Provinces of north-central Oman. One Total Petroleum System and corresponding assessment unit, the North Oman Huqf/`Q'? Haushi(!) Total Petroleum System (201401) and Ghaba-Makarem Combined Structural Assessment Unit (20140101), were identified for the Ghaba Salt Basin Province (2014). In the Fahud Salt Basin Province, however, two overlapping Total Petroleum Systems (TPS) were recognized: 1) the North Oman Huqf ? Shu'aiba(!) TPS (201601); Fahud-Huqf Combined Structural Assessment Unit (20160101), and 2) the Middle Cretaceous Natih(!) TPS (201602); Natih-Fiqa Structural/Stratigraphic Assessment Unit (20160201). The boundary for each Total Petroleum System also defines the boundary of the corresponding assessment unit and includes all trap styles and hydrocarbon producing reservoirs within the petroleum system. In both the Ghaba and Fahud Salt Basin Provinces, hydrocarbons were generated from several deeply-buried source rocks within the Infracambrian Huqf Supergroup. One general `North Oman Huqf' type oil is dominant in the Fahud Salt Basin. Oils in the Ghaba Salt Basin are linked to at least two distinct Huqf source-rock units based on oil geochemistry: a general North Oman Huqf-type oil source and a more dominant `questionable unidentified-source' or `Q'-type Huqf oil source. These two Huqf-sourced oils are commonly found as admixtures in reservoirs throughout north-central Oman. Hydrocarbons generated from Huqf sources are produced from a variety of reservoir types and ages ranging from Precambrian to Cretaceous in both the Ghaba and Fahud Salt Basin Provinces. Clastic reservoirs of the Gharif and Al Khlata Formations, Haushi Group (M. Carboniferous to L. Permian), dominate oil production in the Ghaba Salt Basin Province and form the basis for the Huqf/`Q' ? Haushi(!) TPS. In contrast, the Lower Cretaceous Shu'aiba and Middle Cretaceous Natih limestones account for most of the production in the Fahud Salt Basin with about 50 percent of the basin's production from porous, fractured Shu'aiba limestones in Yibal field, thus the name North Oman Huqf ? Shu'aiba(!) TPS. Deep gas is produced mainly from Middle Cambrian to Lower Ordovician clastic reservoirs of the Haima Supergroup. Traps in nearly all hydrocarbon accumulations of these petroleum systems are mainly structural and were formed by one or more mechanisms. These trap-forming mechanisms were mainly periodic halokinesis of the thick Cambrian Ara Salt and consequent folding and faulting from basin loading, rifting, or other major tectonic events, particularly those events forming the Oman Mountains and associated foreland-basin system during the Late Cretaceous and Late Tertiary. Many of the future new-field targets will likely be low-relief, subtle structures, as many of the large structures have been drilled. Oman's recent interest and commitments to liquid natural gas export make deep gas a primary objective in the two North Oman Huqf petroleum systems. New-field exploration of deep gas and exploring deeper targets for gas in existing fields will likely identify a significant gas resource in the next thirty years. Moreover, salt-diapir flank traps in these two North Oman Huqf petroleum systems and salt basin provinces have gone essentially untested and will likely be targeted in the near-future. The Middle Cretaceous Natih(!) TPS is a small efficient system of the Fahud Salt Basin. Natih source rocks are only mature in the Late Cretaceous/Tertiary foredeep and production is primarily from Natih reservoirs; minor production from the Shu'aiba limestone is documented along fault-dip structures. Most traps are structural and are related to development of the foreland basin and formation of the Oman Mountains. Future targets of the Natih TPS will be less obvious than those of Fahud and Natih fields and likely includ

Ghaba salt basin province and Fahud salt basin province, Oman; geological overview and total petroleum systems

USGS Publications Warehouse

Pollastro, Richard M.

1999-01-01

Three Total Petroleum Systems each consisting of one assessment unit have been identified in the Ghaba and Fahud Salt Basin Provinces of north-central Oman. One Total Petroleum System and corresponding assessment unit, the North Oman Huqf/?Q??Haushi(!) Total Petroleum System (201401) and Ghaba- Makarem Combined Structural Assessment Unit (20140101), were identified for the Ghaba Salt Basin Province (2014). In the Fahud Salt Basin Province, however, two overlapping Total Petroleum Systems (TPS) were recognized: (1) the North Oman Huqf?Shu?aiba(!) TPS (201601); Fahud-Huqf Combined Structural Assessment Unit (20160101), and (2) the middle Cretaceous Natih(!) TPS (201602); Natih-Fiqa Structural/Stratigraphic Assessment Unit (20160201). The boundary for each Total Petroleum System also defines the boundary of the corresponding assessment unit and includes all trap styles and hydrocarbon-producing reservoirs within the petroleum system. In both the Ghaba and Fahud Salt Basin Provinces, hydrocarbons were generated from several deeply buried source rocks within the Infracambrian Huqf Supergroup. One general ?North Oman Huqf? type oil is dominant in the Fahud Salt Basin. Oils in the Ghaba Salt Basin are linked to at least two distinct Huqf source-rock units based on oil geochemistry: a general North Oman Huqf-type oil source and a more dominant ?questionable unidentified source? or ?Q?-type Huqf oil source. These two Huqf-sourced oils are commonly found as admixtures in reservoirs throughout northcentral Oman. Hydrocarbons generated from Huqf sources are produced from a variety of reservoir types and ages ranging from Precambrian to Cretaceous in both the Ghaba and Fahud Salt Basin Provinces. Clastic reservoirs of the Gharif and Al Khlata Formations, Haushi Group (middle Carboniferous to Lower Permian), dominate oil production in the Ghaba Salt Basin Province and form the basis for the Huqf/?Q??Haushi(!) TPS. In contrast, the Lower Cretaceous Shu?aiba and middle Cretaceous Natih limestones account for most of the production in the Fahud Salt Basin with about 50 percent of the basin?s production from porous, fractured Shu?aiba limestones in Yibal field, thus the name North Oman Huqf? Shu?aiba(!) TPS. Deep gas is produced mainly from Middle Cambrian to Lower Ordovician clastic reservoirs of the Haima Supergroup. Traps in nearly all hydrocarbon accumulations of these petroleum systems are mainly structural and were formed by one or more 3 mechanisms. These trap-forming mechanisms were mainly periodic halokinesis of the thick Cambrian Ara Salt and consequent folding and faulting from basin loading, rifting, or other major tectonic events, particularly those events forming the Oman Mountains and associated foreland-basin system during the Late Cretaceous and late Tertiary. Many of the future new-field targets will likely be low-relief, subtle structures, as many of the large structures have been drilled. Oman?s recent interest and commitments to liquid natural gas export make deep gas a primary objective in the two North Oman Huqf petroleum systems. New-field exploration of deep gas and exploring deeper targets for gas in existing fields will likely identify a significant gas resource in the next 30 years. Moreover, salt-diapir flank traps in these two North Oman Huqf petroleum systems and salt basin provinces have gone essentially untested and will likely be targeted in the near future. The middle Cretaceous Natih(!) TPS is a small efficient system of the Fahud Salt Basin. Natih source rocks are only mature in the Late Cretaceous/Tertiary foredeep and production is primarily from Natih reservoirs; minor production from the Shu?aiba limestone is documented along fault-dip structures. Most traps are structural and are related to development of the foreland basin and formation of the Oman Mountains. Future targets of the Natih TPS will be less obvious

Injection by hydrostatic pressure in conjunction with electrokinetic force on a microfluidic chip.

PubMed

Gai, Hongwei; Yu, Linfen; Dai, Zhongpeng; Ma, Yinfa; Lin, Bingcheng

2004-06-01

A simple method was developed for injecting a sample on a cross-form microfluidic chip by means of hydrostatic pressure combined with electrokinetic forces. The hydrostatic pressure was generated simply by adjusting the liquid level in different reservoirs without any additional driven equipment such as a pump. Two dispensing strategies using a floating injection and a gated injection, coupled with hydrostatic pressure loading, were tested. The fluorescence observation verified the feasibility of hydrostatic pressure loading in the separation of a mixture of fluorescein sodium salt and fluorescein isothiocyanate. This method was proved to be effective in leading cells to a separation channel for single cell analysis.

Carbon export in the naturally iron-fertilized Kerguelen area of the Southern Ocean based on the 234Th approach

NASA Astrophysics Data System (ADS)

Planchon, F.; Ballas, D.; Cavagna, A.-J.; Bowie, A. R.; Davies, D.; Trull, T.; Laurenceau, E.; Van Der Merwe, P.; Dehairs, F.

2014-11-01

The Kerguelen Plateau region in the Indian sector of the Southern Ocean supports annually a large-scale phytoplankton bloom which is naturally fertilized with iron. As part of the second KErguelen Ocean and Plateau compared Study expedition (KEOPS2) in austral spring (October-November 2011), we examined upper-ocean Particulate Organic Carbon (POC) export using the 234Th approach. We aimed at characterizing the spatial and the temporal variability of POC export production at high productivity sites over and downstream the Kerguelen plateau. Export production is compared to a High Nutrient Low Chlorophyll area upstream of the plateau in order to assess the impact of iron-induced productivity on the vertical export of carbon. Deficits in 234Th activities relative to its parent nuclide 238U were observed at all stations in surface waters, indicating that scavenging by particles occurred during the early stages of the phytoplankton bloom. 234Th export was lowest at reference station R-2 (412 ± 134 dpm m-2 d-1) and highest inside a~permanent meander of the Polar Front (PF) at stations E (1995 ± 176 dpm m-2 d-1, second visit E-3) where a detailed time series was obtained as part of a~pseudo-lagrangian study. 234Th export over the central plateau was relatively limited at station A3 early (776 ± 171 dpm m-2 d-1, first visit A3-1) and late in the survey (993 ± 223 dpm m-2 d-1, second visit A3-2), but it was higher at high biomass stations TNS-8 (1372 ± 255 dpm m-2 d-1) and E-4W (1068 ± 208 dpm m-2 d-1) in waters which could be considered as derived from plateau. Limited 234Th export of 973 ± 207 dpm m-2 d-1 was also found in the northern branch of the Kerguelen bloom located downstream of the island, north of the PF (station F-L). The 234Th results support that Fe fertilization increased particle export in all iron fertilized waters. The impact was greatest in the recirculation feature (3-4 fold at 200 m depth), but more moderate over the central Kerguelen plateau and in the northern plume of the Kerguelen bloom (∼2-fold at 200 m depth). The C : Th ratio of large (> 53 μm) potentially sinking particles collected via sequential filtration using in situ pumping (ISP) systems were used to convert the 234Th flux into a POC export flux. The C : Th ratios of sinking particles were highly variable (range: 3.1 ± 0.1-10.5 ± 0.2 μmol dpm-1) with no clear site related trend, despite the variety of ecosystem responses in the fertilized regions. C : Th ratios showed a decreasing trend between 100 and 200 m depth suggesting preferential loss of carbon relative to 234Th possibly due to heterotrophic degradation and/or grazing activity. Comparison of the C : Th ratios within sinking particles obtained with the drifting sediment traps showed in most cases very good agreement to those collected via ISP deployments (> 53 μm particles). Carbon export production varied between 3.5 ± 0.9 mmol m-2 d-1 and 11.8 ± 1.3 mmol m-2 d-1 from the upper 100 m and between 1.8 ± 0.9 mmol m-2 d-1 and 8.2 ± 0.9 mmol m-2 d-1 from the upper 200 m. Highest export production was found inside the PF meander with a range of 5.4 ± 0.7 mmol m-2 d-1 to 11.8 ± 1.1 mmol m-2 d-1 at 100 m depth decreasing to 5.3 ± 1.0 mmol m-2 d-1 to 8.2 ± 0.8 mmol m-2 d-1 at 200 m depth over the 19 day survey period. The impact of Fe fertilization is highest inside the PF meander with 2.9- up to 4.5-fold higher carbon flux at 200 m depth in comparison to the HNLC control station. The impact of Fe fertilization was significantly less over the central plateau (stations A3 and E-4W) and in the northern branch of the bloom (station F-L) with 1.6- up to 2.0-fold higher carbon flux compared to the reference station R. Export efficiencies (ratio of export to primary production) were particularly variable with relatively high values in the recirculation feature (6-27%) and low values (1-5%) over the central plateau (station A3) and north of the PF (station F-L) indicating spring biomass accumulation. Comparison with KEOPS1 results indicated that carbon export production is much lower during the onset of the bloom in austral spring in comparison to the peak and declining phase in late summer.

West Hackberry Strategic Petroleum Reserve site brine-disposal monitoring, Year I report. Volume IV. Bibliography and supporting data for physical oceanography. Final report. [421 references

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeRouen, L.R.; Hann, R.W.; Casserly, D.M.

This project centers around the Strategic Petroleum Site (SPR) known as the West Hackberry salt dome which is located in southwestern Louisiana and which is designed to store 241 million barrels of crude oil. Oil storage caverns are formed by injecting water into salt deposits, and pumping out the resulting brine. Studies described in this report were designed as follow-on studies to three months of pre-discharge characterization work, and include data collected during the first year of brine leaching operations. The objectives were to: (1) characterize the environment in terms of physical, chemical and biological attributes; (2) determine if significantmore » adverse changes in ecosystem productivity and stability of the biological community are occurring as a result of brine discharge; and (3) determine the magnitude of any change observed. Volume IV contains the following: bibliography; appendices for supporting data for physical oceanography, and summary of the physical oceanography along the western Louisiana coast.« less

Ion transport in broad bean leaf mesophyll under saline conditions.

PubMed

Percey, William J; Shabala, Lana; Breadmore, Michael C; Guijt, Rosanne M; Bose, Jayakumar; Shabala, Sergey

2014-10-01

Salt stress reduces the ability of mesophyll tissue to respond to light. Potassium outward rectifying channels are responsible for 84 % of Na (+) induced potassium efflux from mesophyll cells. Modulation in ion transport of broad bean (Vicia faba L.) mesophyll to light under increased apoplastic salinity stress was investigated using vibrating ion-selective microelectrodes (the MIFE technique). Increased apoplastic Na(+) significantly affected mesophyll cells ability to respond to light by modulating ion transport across their membranes. Elevated apoplastic Na(+) also induced a significant K(+) efflux from mesophyll tissue. This efflux was mediated predominately by potassium outward rectifying channels (84 %) and the remainder of the efflux was through non-selective cation channels. NaCl treatment resulted in a reduction in photosystem II efficiency in a dose- and time-dependent manner. In particular, reductions in Fv'/Fm' were linked to K(+) homeostasis in the mesophyll tissue. Increased apoplastic Na(+) concentrations induced vanadate-sensitive net H(+) efflux, presumably mediated by the plasma membrane H(+)-ATPase. It is concluded that the observed pump's activation is essential for the maintenance of membrane potential and ion homeostasis in the cytoplasm of mesophyll under salt stress.

Improving ASR Recovery Efficiency by Partially-penetrating Wells in Brackish Aquifers

NASA Astrophysics Data System (ADS)

Chen, Y.

2015-12-01

Aquifer storage and recovery (ASR) is a proven cost-effective powerful technology for environmental protection and water resources optimization. The recovery efficiency (RE) is regarded as the key criteria for evaluating the ASR performance. In this study, a particular ASR scheme with the fully-penetrating well (FPW) for injection and the partially-penetrating well (PPW) for recovery is proposed to improve the RE for ASR schemes implemented in brackish aquifers. This design appreciates the tilting shape of the interface with underlying heavier salt water. For the FPW, recovery has to be terminated as soon as the interface toe reaches the well, while the toe can be pulled up to the PPW for recovery termination, resulting in later breakthrough of salt water into the pumping well, more recoverable water extracted from the shallow layers, and a higher RE. Key hydrogeological and operational parameters affecting the RE were investigated by numerical simulations. Results demonstrated the effectiveness and efficiency of the new ASR scheme and provided practical guidance for designing such a scheme in various hydrogeological conditions.

Photonic Molecule Lasers Revisited

NASA Astrophysics Data System (ADS)

Gagnon, Denis; Dumont, Joey; Déziel, Jean-Luc; Dubé, Louis J.

2014-05-01

Photonic molecules (PMs) formed by coupling two or more optical resonators are ideal candidates for the fabrication of integrated microlasers, photonic molecule lasers. Whereas most calculations on PM lasers have been based on cold-cavity (passive) modes, i.e. quasi-bound states, a recently formulated steady-state ab initio laser theory (SALT) offers the possibility to take into account the spectral properties of the underlying gain transition, its position and linewidth, as well as incorporating an arbitrary pump profile. We will combine two theoretical approaches to characterize the lasing properties of PM lasers: for two-dimensional systems, the generalized Lorenz-Mie theory will obtain the resonant modes of the coupled molecules in an active medium described by SALT. Not only is then the theoretical description more complete, the use of an active medium provides additional parameters to control, engineer and harness the lasing properties of PM lasers for ultra-low threshold and directional single-mode emission. We will extend our recent study and present new results for a number of promising geometries. The authors acknowledge financial support from NSERC (Canada) and the CERC in Photonic Innovations of Y. Messaddeq.

Earth observations taken from orbiter Discovery during STS-85 mission

NASA Image and Video Library

1997-08-08

STS085-705-062 (7 - 19 August 1997) --- The Great Salt is one of the most saline inland bodies of water in the world and is the largest inland body of salt water in the Western Hemisphere. The lake is fed by three rivers (Bear, Weber and Jordon) and has no outlet. The water level varies with the amount of rainfall and evaporation in the basin. The distinct line across the center of the lake is the Lucin Cutoff. It is a 30 mile (48 kilometers), east-west causeway built in 1959 to support a rail line. The causeway connects the cities of Ogden and Lucin and affects the water level of the lake. Because the lake's main tributaries enter from the south, the water level of the southern section is several inches higher than that of the northern part. The Great Salt Lake's record high levels in the mid-1980's threatened the Lucin Cutoff, highways and sewage-treatment plants along the shore -- in 1987 pumps were installed that began draining some of the excess water into the Great Salt Lake Desert to the west. The resulting new body of water was called the Newfoundland Evaporation Basin -- it contains dissolved minerals, primarily sodium and chloride along with sulfate, magnesium, and potassium. The dissolved minerals, turbidity and microorganisms which can survive in saline water give the lake its varying colors. In this photo the north portion is dark red. The crew said that it looked like dirt when they first saw it. Crews can not remember the north portion ever looking so red -- it is usually a light blue color.

Late summer particulate organic carbon export and twilight zone remineralisation in the Atlantic sector of the Southern Ocean

NASA Astrophysics Data System (ADS)

Planchon, F.; Cavagna, A.-J.; Cardinal, D.; André, L.; Dehairs, F.

2013-02-01

As part of the GEOTRACES Bonus-GoodHope (BGH) expedition (January-March 2008) in the Atlantic sector of the Southern Ocean, particulate organic carbon (POC) export was examined from the surface to the mesopelagic twilight zone using water column distributions of total 234Th and biogenic particulate Ba (Baxs). Surface POC export production was estimated from steady state and non steady state modelling of 234Th fluxes, which were converted into POC fluxes, using the POC/234Th ratio of large, potentially sinking particles (> 53 μm) collected via in situ pumps. Deficits in 234Th activities were observed at all stations from the surface to the bottom of the mixed layer, yielding 234Th export fluxes from the upper 100 m of 496 ± 214 dpm m-2 d-1 to 1195 ± 158 dpm m-2 d-1 for the steady state model and of 149 ±517 dpm m-2 d-1 to 1217 ± 231 dpm m-2 d-1 for the non steady state model. Using the POC/234Thp ratio of sinking particles (ratios varied from 1.7 ± 0.2 μmol dpm-1 to 4.8 ± 1.9 μmol dpm-1) POC export production at 100 m was calculated to range between 0.9 ± 0.4 and 5.1 ± 2.1 mmol C m-2 d-1,assuming steady state and between 0.3 ± 0.9 m-2 d-1 and 4.9 ± 3.3 mmol C m-2 d-1, assuming non steady state. From the comparison of both approaches, it appears that during late summer export decreased by 56 to 16% for the area between the sub-Antarctic zone and the southern Antarctic Circumpolar Current Front (SACCF), whereas it remained rather constant over time in the HNLC area south of the SACCF. POC export represented only 6 to 54% of new production, indicating that export efficiency was, in general, low, except in the vicinity of the SACCF, where export represented 56% of new production. Attenuation of the POC sinking flux in the upper mesopelagic waters (100-600 m depth interval) was evidenced both, from excess 234Th activities and from particulate biogenic Ba (Baxs) accumulation. Excess 234Th activities, reflected by 234Th/238U ratios as large as 1.21 ± 0.05, are attributed to remineralisation/disaggregation of 234Th-bearing particles. The accumulation of excess 234Th in the 100-600 m depth interval ranged from 458 ± 633 dpm m-2 d-1 to 3068 ± 897 dpm m-2 d-1, assuming steady state. Using the POC/234Thp ratio of sinking particles (> 53 μm), this 234Th accumulation flux was converted into a POC remineralisation flux which ranged between 0.9 ± 1.2 mmol C m-2 d-1 and 9.2 ± 2.9 mmol C m-2 d-1. Mesopelagic particulate biogenic Ba has been reported to reflect bacterial degradation of organic matter and to be related to oxygen consumption and bacterial carbon respiration. We observed that the highest Baxs contents (reaching up to > 1000 pM), in general, occurred between 200 and 400 m. Depth-weighted average mesopelagic Baxs (meso-Baxs) values were converted into respired C fluxes, which ranged between 0.23 and 6.4 mmol C m-2 d-1, in good agreement with 234Th-based remineralisation fluxes. A major outcome from this study is the observed significant positive correlation between POC remineralisation as estimated from meso-Baxs contents and from 234Th excess (R2 = 0.73; excluding 2 outliers). Remineralisation of POC in the twilight zone was particularly efficient relative to POC export resulting in negligible bathypelagic (> 600 m) POC export fluxes in the sub-Antarctic zone, the Polar Front zone and the northern Weddell Gyre, while the subtropical zone as well as the vicinity of the SACCF had significant deep POC fluxes.

Interaction of Extreme Halophilic Archaea With the Evaporites of the Solar Salterns Guerrero Negro Baja California, Mexico

NASA Astrophysics Data System (ADS)

Tamez, P.; Lopez-Cortés, A.

2008-12-01

Hypersaline environments have been significant reservoirs for the long-term evolution of specifically adapted microorganisms. Characterized to have higher salt concentrations (up to 35 g/L), they are worldwide distributed and have a commercial significance. Exportadora de Sal, Guerrero Negro, Mexico has a multipond salterns system designed to harvest common salt (NaCl) from sea water. To achieve this purpose, sea water is pumped through a set of shallow ponds where water evaporates and salts concentrate. Sequential precipitation of CaCO3, CaSO4 2H2O and NaCl occurs in a mineral formations call it evaporites. In the interior of those gypsum-encrusted and halite-encrusted minerals, communities of extremely salt-loving archaea prosper. Previous studies have showed the influence of Haloarchaeal cells in the formation of larger fluid inclusions than crystals formed in sterile salt solutions. S-layer envelopes and cells of Haloarcula strain SP8807 contributed to the nucleation of new crystals of NaCl. Given the significance of the scope in phylogenetic archaeal diversity research, this study had a polyphasic approach. SEM micrographs from a 21- 31% (w/v) gradient salt multipond system evaporites, gave an insight profile of the extreme halophilic archaeal communities thriving in the surface of the gypsum and halite evaporites. Halite crystals were form after 21 days of incubation in solid medium with archaeal cells. Both culture and non-culture dependent methods, Nested-PCR-DGGE analysis and sequencing of 16S rDNA amplified fragment genes from environmental samples and isolated strains were used for this purpose. We isolate three strains from Pond 9 (21.07% total salt concentration) and one strain from Cristallizer 20 (25.15% total salt concentration). 16S rDNA signaling gave 99% of similarity with Halogeometricum borinquense, sequence AF002984, two other strains were 99% of similarity with Halobacterium salinarum, sequence AJ496185 these strains shown different colony morphology. Other strain match, with 99% of similarity, with three sequences Haloarcula: Haloarcula japonica (EF645686), Haloarcula hispanica (DQ089681) and Haloarcula marismortui (X61689), differences among them were only 3 base pairs. We suggest that strain, C205030908, could correspond to Haloarcula californiae previously reported by Javor et al, (1982), from which there is not sequence known. Nested-PCR-DGGE analysis showed a pattern of 11 bands, meaning the archaeal community is more complex than we could detect by culture approach.

Ecological response to collapse of the biological pump following the mass extinction at the Cretaceous-Paleogene boundary

NASA Astrophysics Data System (ADS)

Vellekoop, Johan; Woelders, Lineke; Açikalin, Sanem; Smit, Jan; van de Schootbrugge, Bas; Yilmaz, Ismail Ö.; Brinkhuis, Henk; Speijer, Robert P.

2017-02-01

It is commonly accepted that the mass extinction associated with the Cretaceous-Paleogene (K-Pg) boundary (˜ 66 Ma) is related to the environmental effects of a large extraterrestrial impact. The biological and oceanographic consequences of the mass extinction are, however, still poorly understood. According to the Living Ocean model, the biological crisis at the K-Pg boundary resulted in a long-term reduction of export productivity in the early Paleocene. Here, we combine organic-walled dinoflagellate cyst (dinocyst) and benthic foraminiferal analyses to provide new insights into changes in the coupling of pelagic and benthic ecosystems. To this end, we perform dinocyst and benthic foraminiferal analyses on the recently discovered Tethyan K-Pg boundary section at Okçular, Turkey, and compare the results with other K-Pg boundary sites in the Tethys. The post-impact dominance of epibenthic morphotypes and an increase of inferred heterotrophic dinocysts in the early Paleocene at Okçular are consistent with published records from other western Tethyan sites. Together, these records indicate that during the early Paleocene more nutrients remained available for the Tethyan planktonic community, whereas benthic communities were deprived of food. Hence, in the post-impact phase the reduction of export productivity likely resulted in enhanced recycling of nutrients in the upper part of the water column, all along the western Tethyan margins.

Schedules of controlled substances: temporary placement of three synthetic phenethylamines into Schedule I. Final order.

PubMed

2013-11-15

The Deputy Administrator of the Drug Enforcement Administration (DEA) is issuing this final order to temporarily schedule three synthetic phenethylamines into the Controlled Substances Act (CSA) pursuant to the temporary scheduling provisions of 21 U.S.C. 811(h). The substances are 2-(4-iodo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25I-NBOMe; 2C-I-NBOMe; 25I; Cimbi-5), 2-(4-chloro-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25C-NBOMe; 2C-C-NBOMe; 25C; Cimbi-82), and 2-(4-bromo-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine (25B-NBOMe; 2C-B-NBOMe; 25B; Cimbi-36) [hereinafter 25I-NBOMe, 25C-NBOMe, and 25B-NBOMe]. This action is based on a finding by the Deputy Administrator that the placement of these synthetic phenethylamines and their optical, positional, and geometric isomers, salts and salts of isomers in schedule I of the CSA is necessary to avoid an imminent hazard to the public safety. As a result of this order, the regulatory controls and administrative, civil, and criminal sanctions applicable to schedule I controlled substances will be imposed on persons who handle (manufacture, distribute, dispense, import, export, engage in research, conduct instructional activities, and possess), or propose to handle these synthetic phenethylamines.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickenheim, B.; Hansen, E.; Leishear, R.

A 10-inch READCO mixer is used for mixing the premix (45 (wt%) fly ash, 45 wt% slag, and 10 wt% portland cement) with salt solution in the Saltstone Production Facility (SPF). The Saltstone grout free falls into the grout hopper which feeds the suction line leading to the Watson SPX 100 duplex hose pump. The Watson SPX 100 pumps the grout through approximately 1500 feet of piping prior to being discharged into the Saltstone Disposal Facility (SDF) vaults. The existing grout hopper has been identified by the Saltstone Enhanced Low Activity Waste Disposal (ELAWD) project for re-design. The current nominalmore » working volume of this hopper is 12 gallons and does not permit handling an inadvertent addition of excess dry feeds. Saltstone Engineering has proposed a new hopper tank that will have a nominal working volume of 300 gallons and is agitated with a mechanical agitator. The larger volume hopper is designed to handle variability in the output of the READCO mixer and process upsets without entering set back during processing. The objectives of this task involve scaling the proposed hopper design and testing the scaled hopper for the following processing issues: (1) The effect of agitation on radar measurement. Formation of a vortex may affect the ability to accurately measure the tank level. The agitator was run at varying speeds and with varying grout viscosities to determine what parameters cause vortex formation and whether measurement accuracy is affected. (2) A dry feeds over addition. Engineering Calculating X-ESR-Z-00017 1 showed that an additional 300 pounds of dry premix added to a 300 gallon working volume would lower the water to premix ratio (W/P) from the nominal 0.60 to 0.53 based on a Salt Waste Processing Facility (SWPF) salt simulant. A grout with a W/P of 0.53 represents the upper bound of grout rheology that could be processed at the facility. A scaled amount of dry feeds will be added into the hopper to verify that this is a recoverable situation. (3) The necessity of baffles in the hopper. The preference of the facility is not to have baffles in the hopper; however, if the initial testing indicates inadequate agitation or difficulties with the radar measurement, baffles will be tested.« less

Tdp studies and tests for C. A. Energia Electrica de Venezuela (enelven) at planta ramon laguna, units RL-17 and RL-10. Volume 2. Unit RL-10 boiler condition assessment report. Export trade information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-03-28

The study, conducted by Babcock and Wilcox, was funded by the U.S. Trade and Development agency on behalf of Enelven. In order to maximize generated power output and minimize operating costs at Planta Ramon Laguna, tests were done to evaluate the condition of equipment at the plant. In order to identify any damage and determine the operating output of each unit, assessments were done of the furnaces, boilers, generators and boiler feed pumps being used in the plant. The report presents the results of these tests. This is the second of three volumes and it includes the following section: (1)more » Condition Assessment of Unit RL-10 Boiler.« less

Earth observations taken from shuttle orbiter Columbia during STS-87 mission

NASA Image and Video Library

1997-11-23

STS087-703-089 (19 November – 5 December 1997) --- Featured in this view is center pivot irrigation in central Saudi Arabia. Abundant petroleum has provided the energy source for deep-well pumps that tap groundwater stored in bedrock many thousands of years ago when the climate was much wetter. The fields are carved out of ancient alluvial fan deposits, also formed when rainfall was much greater; the fields are pushed right to the edge of the Nafud al Mazhur (sand sea), representative of the present climate. The mining of petroleum and groundwater has enabled Saudi Arabia to become an exporter of wheat and other commodities, in addition to the oil for which it is famous. This picture is one of the 70mm Earth observation visuals used by the crew at its post flight presentation events.

In-well pumped mid-infrared PbTe/CdTe quantum well vertical external cavity surface emitting lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khiar, A., E-mail: amir.khiar@jku.at; Witzan, M.; Hochreiner, A.

2014-06-09

Optical in-well pumped mid-infrared vertical external cavity surface emitting lasers based on PbTe quantum wells embedded in CdTe barriers are realized. In contrast to the usual ternary barrier materials of lead salt lasers such as PbEuTe of PbSrTe, the combination of narrow-gap PbTe with wide-gap CdTe offers an extremely large carrier confinement, preventing charge carrier leakage from the quantum wells. In addition, optical in-well pumping can be achieved with cost effective and readily available near infrared lasers. Free carrier absorption, which is a strong loss mechanism in the mid-infrared, is strongly reduced due to the insulating property of CdTe. Lasingmore » is observed from 85 K to 300 K covering a wavelength range of 3.3–4.2 μm. The best laser performance is achieved for quantum well thicknesses of 20 nm. At low temperature, the threshold power is around 100 mW{sub P} and the output power more than 700 mW{sub P}. The significance of various charge carrier loss mechanisms are analyzed by modeling the device performance. Although Auger losses are quite low in IV–VI semiconductors, an Auger coefficient of C{sub A} = 3.5 × 10{sup −27} cm{sup 6} s{sup −1} was estimated for the laser structure, which is attributed to the large conduction band offset.« less

A seasonal carbon budget for a naturally iron-fertilized bloom over the Kerguelen Plateau in the Southern Ocean

NASA Astrophysics Data System (ADS)

Jouandet, Marie Paule; Blain, Stephane; Metzl, Nicolas; Brunet, Christian; Trull, Thomas W.; Obernosterer, Ingrid

2008-03-01

During the Kerguelen Ocean and Plateau compared Study (KEOPS, January-February 2005), a high-resolution distribution of surface fugacity of carbon dioxide ( fCO 2) was obtained from underway measurements. The stations in the core of the naturally iron-fertilized bloom were characterized by low fCO 2 (311±8 μatm) compared to the atmosphere, thus representing a large CO 2 sink. This contrasted with stations typical of high-nutrient low-chlorophyll (HNLC) conditions where the surface water was roughly in equilibrium with the atmosphere ( fCO 2=372±5 μatm). The vertical distribution of dissolved inorganic carbon (DIC) also was obtained at stations within and outside the bloom. Based on this data set, we constructed a carbon budget for the mixed layer that allowed us to determine the seasonal net community production (NCP season) and the seasonal carbon export in two contrasting environments. The robustness of the approach and the errors also were estimated. The NCP season in the core of the bloom was 6.6±2.2 mol m -2, typical of productive areas of the Southern Ocean. At the HNLC station the NCP season was 3 times lower than in the bloom. Our estimate of the daily net community production (NCP daily) within the bloom compares well with shipboard measurements of NCP. The NCP daily obtained above the Kerguelen Plateau was of the same order as the estimates from Southern Ocean artificial iron-fertilization experiments (SOIREE and EisenEx). The seasonal carbon export was derived from NCP season after subtraction of the seasonal accumulation of particulate and dissolved organic carbon. In the bloom, the carbon export (5.4±1.9 mol m -2) was 3-fold higher than at the HNLC station (1.7±0.4 mol m -2). Comparison of our results to artificial iron-fertilization experiments shows that the biological pump is enhanced by natural iron fertilization.

Sequential Activation of Classic PKC and Estrogen Receptor α Is Involved in Estradiol 17ß-D-Glucuronide-Induced Cholestasis

PubMed Central

Barosso, Ismael R.; Zucchetti, Andrés E.; Boaglio, Andrea C.; Larocca, M. Cecilia; Taborda, Diego R.; Luquita, Marcelo G.; Roma, Marcelo G.; Crocenzi, Fernando A.; Sánchez Pozzi, Enrique J.

2012-01-01

Estradiol 17ß-d-glucuronide (E17G) induces acute cholestasis in rat with endocytic internalization of the canalicular transporters bile salt export pump (Abcb11) and multidrug resistance-associated protein 2 (Abcc2). Classical protein kinase C (cPKC) and PI3K pathways play complementary roles in E17G cholestasis. Since non-conjugated estradiol is capable of activating these pathways via estrogen receptor alpha (ERα), we assessed the participation of this receptor in the cholestatic manifestations of estradiol glucuronidated-metabolite E17G in perfused rat liver (PRL) and in isolated rat hepatocyte couplets (IRHC). In both models, E17G activated ERα. In PRL, E17G maximally decreased bile flow, and the excretions of dinitrophenyl-glutathione, and taurocholate (Abcc2 and Abcb11 substrates, respectively) by 60% approximately; preadministration of ICI 182,780 (ICI, ERα inhibitor) almost totally prevented these decreases. In IRHC, E17G decreased the canalicular vacuolar accumulation of cholyl-glycylamido-fluorescein (Abcb11 substrate) with an IC50 of 91±1 µM. ICI increased the IC50 to 184±1 µM, and similarly prevented the decrease in the canalicular vacuolar accumulation of the Abcc2 substrate, glutathione-methylfluorescein. ICI also completely prevented E17G-induced delocalization of Abcb11 and Abcc2 from the canalicular membrane, both in PRL and IRHC. The role of ERα in canalicular transporter internalization induced by E17G was confirmed in ERα-knocked-down hepatocytes cultured in collagen sandwich. In IRHC, the protection of ICI was additive to that produced by PI3K inhibitor wortmannin but not with that produced by cPKC inhibitor Gö6976, suggesting that ERα shared the signaling pathway of cPKC but not that of PI3K. Further analysis of ERα and cPKC activations induced by E17G, demonstrated that ICI did not affect cPKC activation whereas Gö6976 prevented that of ERα, indicating that cPKC activation precedes that of ERα. Conclusion: ERα is involved in the biliary secretory failure induced by E17G and its activation follows that of cPKC. PMID:23209816

A NOVEL PROCESS TO USE SALT CAVERNS TO RECEIVE SHIP BORNE LNG

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael M. McCall; William M. Bishop; Marcus Krekel

2005-05-31

This cooperative research project validates use of man made salt caverns to receive and store the cargoes of LNG ships in lieu of large liquid LNG tanks. Salt caverns will not tolerate direct injection of LNG because it is a cryogenic liquid, too cold for contact with salt. This research confirmed the technical processes and the economic benefits of pressuring the LNG up to dense phase, warming it to salt compatible temperatures and then directly injecting the dense phase gas into salt caverns for storage. The use of salt caverns to store natural gas sourced from LNG imports, particularly whenmore » located offshore, provides a highly secure, large scale and lower cost import facility as an alternative to tank based LNG import terminals. This design can unload a ship in the same time as unloading at a tank based terminal. The Strategic Petroleum Reserve uses man made salt caverns to securely store large quantities of crude oil. Similarly, this project describes a novel application of salt cavern gas storage technologies used for the first time in conjunction with LNG receiving. The energy industry uses man made salt caverns to store an array of gases and liquids but has never used man made salt caverns directly in the importation of LNG. This project has adapted and expanded the field of salt cavern storage technology and combined it with novel equipment and processes to accommodate LNG importation. The salt cavern based LNG receiving terminal described in the project can be located onshore or offshore, but the focus of the design and cost estimates has been on an offshore location, away from congested channels and ports. The salt cavern based terminal can provide large volumes of gas storage, high deliverability from storage, and is simplified in operation compared to tank based LNG terminals. Phase I of this project included mathematical modeling that proved a salt cavern based receiving terminal could be built at lower capital cost, and would have significantly higher delivery capacity, shorter construction time, and be much more secure than a conventional liquid tank based terminal. Operating costs of a salt cavern terminal are lower than tank based terminals because ''boil off'' is eliminated and maintenance costs of caverns are lower than LNG tanks. Phase II included the development of offshore mooring designs, wave tank tests, high pressure LNG pump field tests, heat exchanger field tests, and development of a model offshore LNG facility and cavern design. Engineers designed a model facility, prepared equipment lists, and confirmed capital and operating costs. In addition, vendors quoted fabrication and installation costs, confirming that an offshore salt cavern based LNG terminal would have lower capital and operating costs than a similarly sized offshore tank based terminal. Salt cavern storage is infinitely more secure than surface storage tanks, far less susceptible to accidents or purposeful damage, and much more acceptable to the community. More than thirty industry participants provided cost sharing, technical expertise, and guidance in the conduct and evaluation of the field tests, facility design and operating and cost estimates. Their close participation has accelerated the industry's acceptance of the conclusions of this research. The industry participants also developed and submitted several alternative designs for offshore mooring and for high pressure LNG heat exchangers in addition to those that were field tested in this project. HNG Storage, a developer, owner, and operator of natural gas storage facilities, and a participant in the DOE research has announced they will lead the development of the first offshore salt cavern based LNG import facility. Which will be called the Freedom LNG Terminal. It will be located offshore Louisiana, and is expected to be jointly developed with other members of the research group yet to be named. An offshore port license application is scheduled to be filed by fourth quarter 2005 and the terminal could be operational by 2009. This terminal allows the large volume importation of LNG without disrupting coastal port operations by being offshore, out of sight of land.« less

Surface ocean carbon isotope anomalies on glacial terminations: An alternative view

NASA Astrophysics Data System (ADS)

Lund, D. C.; Cote, M.; Schmittner, A.

2016-12-01

Late Pleistocene glacial terminations are characterized by surface ocean carbon isotope minima on a global scale. During the last deglaciation (i.e. Termination 1), planktonic foraminiferal δ13C anomalies occurred in the Atlantic, Indian, Pacific, and Southern Oceans. Despite the apparently ubiquitous nature of δ13C anomalies on glacial terminations, their cause remains a matter of ongoing debate. The prevailing view is that isotopically light carbon from the abyss was upwelled in the Southern Ocean, resulting in outgassing of 13C-depleted carbon to the atmosphere and its advection to lower latitudes via mode and intermediate waters (Spero and Lea, 2002). Alternatively, carbon isotope minima may be driven by weakening of the biological pump related to circulation-driven changes in the oceanic preformed nutrient budget (Schmittner and Lund, 2015). Here we assess the deep upwelling and biological pump hypotheses using a new compilation of 70 globally-distributed planktonic δ13C records from the published literature. We find that 1) the mean deglacial δ13C anomaly is similar in all ocean basins, 2) the eastern tropical Pacific yields smaller mean δ13C anomalies than the western tropical Pacific, and 3) δ13C anomalies in the Southern Ocean decrease with increasing latitude. Our results are generally inconsistent with the deep upwelling hypothesis, which predicts that the δ13C signal should be largest in the Southern Ocean and upwelling regions. Instead, the spatial pattern in δ13C anomalies supports the biological pump hypothesis, which predicts that reduced export of light carbon from the euphotic zone triggers negative carbon isotope anomalies in the surface ocean and positive anomalies at intermediate depths. Upwelling of relatively 13C-enriched intermediate waters tends to moderate carbon isotope minima in upwelling regions. Our results suggest that the initial rise in atmospheric CO2 during Termination 1 was likely due to weakening of the biological pump associated with a reduction in the Atlantic Meridional Overturning Circulation, consistent with model results (Schmittner and Lund, 2015). Spero, H., and D. Lea (2002) Science 296, 522-525. Schmittner, A., and D. Lund (2015) Climate of the Past 11, 135-152.