Science.gov

Sample records for paso na bacia

  1. 8. VIEW OF EL PASO AND SOUTHWESTERN RAILROAD BRIDGE, PIER ...

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

    8. VIEW OF EL PASO AND SOUTHWESTERN RAILROAD BRIDGE, PIER BETWEEN EAST APPROACH AND RAILROAD, LOOKING NORTH. - El Paso & Southwestern Railroad Rio Grande Bridge, Spanning Rio Grande at Southwestern Railroad, El Paso, El Paso County, TX

  2. 7. VIEW OF EL PASO AND SOUTHWESTERN RAILROAD BRIDGE, PIER ...

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

    7. VIEW OF EL PASO AND SOUTHWESTERN RAILROAD BRIDGE, PIER BETWEEN HIGHWAY AND RAILROAD, LOOKING NORTH. - El Paso & Southwestern Railroad Rio Grande Bridge, Spanning Rio Grande at Southwestern Railroad, El Paso, El Paso County, TX

  3. 4. GENERAL VIEW OF EL PASO AND SOUTHWESTERN RAILROAD BRIDGE, ...

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

    4. GENERAL VIEW OF EL PASO AND SOUTHWESTERN RAILROAD BRIDGE, RAILROAD SPAN, LOOKING NORTH. - El Paso & Southwestern Railroad Rio Grande Bridge, Spanning Rio Grande at Southwestern Railroad, El Paso, El Paso County, TX

  4. 27 CFR 9.84 - Paso Robles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.84 Paso Robles. (a) Name. The name of the viticultural area described in this section is “Paso Robles”. (b) Approved Map. The appropriate map for determining the boundary of the Paso Robles viticultural area is...

  5. 27 CFR 9.84 - Paso Robles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.84 Paso Robles. (a) Name. The name of the viticultural area described in this section is “Paso Robles”. (b) Approved Map. The appropriate map for determining the boundary of the Paso Robles viticultural area is...

  6. 27 CFR 9.84 - Paso Robles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.84 Paso Robles. (a) Name. The name of the viticultural area described in this section is “Paso Robles”. (b) Approved Map. The appropriate map for determining the boundary of the Paso Robles viticultural area is...

  7. 27 CFR 9.84 - Paso Robles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.84 Paso Robles. (a) Name. The name of the viticultural area described in this section is “Paso Robles”. (b) Approved Map. The appropriate map for determining the boundary of the Paso Robles viticultural area is...

  8. 27 CFR 9.84 - Paso Robles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.84 Paso Robles. (a) Name. The name of the viticultural area described in this section is “Paso Robles”. (b) Approved Map. The appropriate map for determining the boundary of the Paso Robles viticultural area is...

  9. Effects of the Paso Robles Geothermal Reservoir on water quality and availability in the Paso Robles Groundwater Basin, California

    NASA Astrophysics Data System (ADS)

    Rytuba, J. J.; Langenheim, V. E.; Goldstein, D.

    2012-12-01

    . Geothermal waters and groundwater mix in the PRGB, resulting in distinct changes in chemistry and quality of water derived from wells that extend into the lower part of the PRF. Geothermal waters and waters from Paso Robles city wells plot on a two-end member mixing line defined by light stable isotopes (δ2H and δ18O) and conservative elements (B, Cl, Na, Li). Most hot spring waters and well waters are a mixture of the two end members, indicating that city waters include a component of geothermal water. In water wells that contain less than 15% geothermal water, water quality is acceptable. Water wells that contain from 15% to 50% geothermal water have high Fe and Mn and require treatment. Water wells that have >50% geothermal water have high H2S and are unpotable. On the east side of the basin, water wells east of the San Juan and Red Hills faults have high levels of Cl, B, and Na, similar to wells in the Paso Robles geothermal system, indicating that a significant component of the geothermal fluid has mixed with these waters. This suggests that the geothermal reservoir extends across the PRGB, and could be used to substantially increase municipal water availability, as long as water production was managed to limit the amount of mixing to <50%.

  10. 76 FR 48833 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-09

    ... Energy Regulatory Commission El Paso Natural Gas Company; Notice of Application Take notice that on July 20, 2011, El Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs, Colorado 80944...) of the Natural Gas Act, to abandon, in place, El Paso's El Paso-Douglas Line (Line No. 1004) in...

  11. 76 FR 76707 - Brian Hamilton; El Paso Natural Gas and El Paso Western Pipelines; Notice of Complaint

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Brian Hamilton; El Paso Natural Gas and El Paso Western Pipelines; Notice of... Improvement Act of 2002, and the Pipeline Hazardous Material Safety Administration, Brian...

  12. 76 FR 77994 - Brian Hamilton v. El Paso Natural Gas, El Paso Western Pipelines; Notice Announcing Docket Number...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-15

    ... Energy Regulatory Commission Brian Hamilton v. El Paso Natural Gas, El Paso Western Pipelines; Notice Announcing Docket Number Change On December 2, 2011, the Commission issued a notice in docket number RP12-220... docket number, RP12-220-000 and give the proceeding a new docket number. This notice changes the...

  13. Landsat's Decades-Long Look at El Paso, Texas

    NASA Video Gallery

    Landsat satellites have captured hundreds of images of the regionsurrounding El Paso, Texas since the program started in 1972. On May30, 2013, Landsat 8 began adding to the program’s extensive ...

  14. 76 FR 5120 - Television Broadcasting Services; El Paso, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-28

    ... From the Federal Register Online via the Government Publishing Office ] FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; El Paso, TX AGENCY: Federal Communications... 73 Television, Television broadcasting. For the reasons discussed in the preamble, the...

  15. 76 FR 61135 - Environmental Impact Statement: El Paso County, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-03

    ...FHWA is issuing this notice to advise the public that the NOI to prepare an environmental impact statement (EIS) for proposed improvements to Loop 375 Border Highway West, in El Paso County, Texas, is being...

  16. Super Guppy Swallows T-38s; Heads for El Paso

    NASA Video Gallery

    Two NASA T-38 aircraft were swallowed whole by NASA's Super Guppy recently on Dryden Flight Research Center's back ramp. The Guppy then airlifted the two retired T-38s to El Paso, Texas, where they...

  17. Social disparities in children's respiratory health in El Paso, Texas.

    PubMed

    Grineski, Sara E; Collins, Timothy W; Chavez-Payan, Paola; Jimenez, Anthony M; Clark-Reyna, Stephanie; Gaines, Marie; Kim, Young-an

    2014-03-01

    The objectives of this study were to assess prevalence of children's respiratory health conditions and to measure and describe social disparities in children's respiratory problems and access to health resources for asthma/wheezing management. Data were collected through a cross-sectional, observational mail survey of all primary caretakers of 4th and 5th grade children in El Paso Independent School District (El Paso, TX, USA). 6295 primary caretakers received surveys at their home address and 1904 surveys were completed and returned for a 30% response rate. El Paso children have high rates of asthma (17%) and allergies (51%). In terms of social disparities, children that are male, not poor, obese, Hispanic, born in El Paso, have a US-born caretaker, and have a caretaker who has lower levels Spanish proficiency have increased odds of respiratory problems. Among children with asthma and wheezing, disparities exist in access to care; those that are poor, with a Spanish-speaking caretaker, or with a foreign-born caretaker had increased odds of seeking care in urgent care center, emergency rooms and hospitals. Results have scholarly and practical implications for broader trends in terms of increasing prevalence of respiratory health problems across multiple scales (from El Paso to the US context to worldwide) and health disparities experienced within the rapidly growing US Hispanic population. PMID:24619157

  18. 76 FR 41235 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ... 28, 2011, El Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs, Colorado 80944... Interstate Gas Company, P.O. Box 1087, Colorado Springs, CO 80944, telephone no. (719) 667-7514, facsimile...

  19. 77 FR 14776 - El Paso Natural Gas Company; Notice of Amendment to Presidential Permit

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-13

    ... notice that on February 20, 2012, El Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs... Nevada Avenue, P.O. Box 1087, Colorado Springs, Colorado 80944, or call at 719-667-7514, or email...

  20. 76 FR 18756 - El Paso Natural Gas Company; Notice of Request Under Blanket Authorization

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-05

    ... Take notice that on March 22, 2011, El Paso Natural Gas Company (El Paso), Post Office Box 1087... application should be directed to Susan C. Stires, Post Box Office 1087, Colorado Springs, CO 80944,...

  1. 75 FR 62515 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ... notice that on September 28, 2010, El Paso Natural Gas Company (EPNG), P.O. Box 1087, Colorado Springs..., Director, Regulatory Affairs, El Paso Natural Gas Company, P.O. Box 1087, Colorado Springs, Colorado...

  2. 77 FR 20617 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-05

    ... export capacity of 366,000 Mcf/d, designed to transport natural gas to a new delivery interconnect with... Energy Regulatory Commission El Paso Natural Gas Company; Notice of Application Take notice that on March 23, 2012, El Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs, Colorado...

  3. 76 FR 28016 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-13

    ... Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs, CO 80944, filed with the Federal... Gas Company, P.O. Box 1087, Colorado Springs, CO 80944, at (719) 667-7514 (phone), (719) 667-7534 (fax... Paso Natural ] Gas Company, P.O. Box 1087, Colorado Springs, Colorado 80944, at (719) 520-4534...

  4. 75 FR 42727 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ... notice that on July 13, 2010, El Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs... Gas Company, P.O. Box 1087, Colorado Springs, Colorado 80944, or by calling (719) 667-7514 (telephone... and General Counsel, El Paso Natural Gas Company, P.O. Box 1087, Colorado Springs, Colorado 80944,...

  5. 76 FR 66708 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ... October 7, 2011, El Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs, Colorado 80904, filed in the above referenced docket an application pursuant to section 3 of the Natural Gas Act (NGA... Department, El Paso Natural Gas Company, P.O. Box 1087, Colorado Springs, Colorado 80904, by telephone...

  6. 76 FR 66711 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ... October 11, 2011, El Paso Natural Gas Company (El Paso), P.O. Box 1087, Colorado Springs, Colorado 80904... application under section 3 of the NGA in Docket No. CP12-7-000, requesting amendment and reissuance of its..., Director, Regulatory Affairs Department, El Paso Natural Gas Company, P.O. Box 1087, Colorado...

  7. PRELIMINARY RESEARCH FINDINGS OF THE EL PASO CHILDREN'S HEALTH STUDY

    EPA Science Inventory

    The El-Paso-Ciudad Juarez area is one of the largest metropolitan areas on the U.S.-Mexico border. Sources of air pollutants inlcude the more than 18 million vehicles, which annually cross between the two cities, heavily traveled roads and interstate freeways, and local indust...

  8. 76 FR 44280 - Television Broadcasting Services; El Paso, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-25

    ... COMMISSION 47 CFR Part 73 Television Broadcasting Services; El Paso, TX AGENCY: Federal Communications... 12, 2009 digital transition deadline, after which the Video Division granted KVIA-TV Special... channel substitution will serve the public interest by significantly improving the public's digital...

  9. The Chicanos of El Paso: A Case of Changing Colonization.

    ERIC Educational Resources Information Center

    Martinez, Oscar J.

    Using historical statistics and key indicators, data were synthesized to identify longitudinal trends and patterns in the social, economic, and political status of El Paso's Chicanos. Data related to group achievement were analyzed. A framework adapted to local conditions based on the internal colonialism model was used for the periodization of El…

  10. 76 FR 19276 - Television Broadcasting Services; El Paso, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-07

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; El Paso, TX AGENCY: Federal Communications... U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Television. Federal...

  11. 76 FR 28946 - Television Broadcasting Services; El Paso, TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-19

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Television Broadcasting Services; El Paso, TX AGENCY: Federal Communications... CFR 1.415 and 1.420. List of Subjects in 47 CFR Part 73 Television Federal Communications...

  12. El Paso Formation - a Lower Ordovician platform carbonate deposit

    SciTech Connect

    Clemons, R.E.

    1987-05-01

    The eastward-transgressive Lower Ordovician El Paso Formation conformably overlies Bliss Sandstone in southern New Mexico. Locally, lower El Paso was deposited on low hills of plutonic and volcanic rocks. The region subsided gradually throughout Canadian time, receiving the El Paso carbonate rock blanket up to 460 m thick. Lithologic and chronologic correlative rocks were deposited over most of the southwestern US as the first Paleozoic carbonate platform sequence. The El Paso Formation contains four members, listed here in ascending order: Hitt Canyon, Jose, McKelligon, and Padre. Gradually decreasing sand content upward through the Hitt Canyon indicates deepening water and/or greater distance to shore. Girvanella(.) oncolites are locally abundant. Stromatolite mounds near the top of the Hitt Canyon, combined with an influx of sand, ooids, and rounded bioclasts in the Jose Member, recorded a shoaling phase. The overlying McKelligon Member contains little or no sand, and sponge-Calathium mounds are prominent at some locales. Stromatolite mounds are interbedded with sponge-Calathium mounds in a few sections. Lower Padre Member beds are typically silty to sandy and locally contain thinly-laminated zones. The Padre contains more restricted fauna that includes traces of ostracods. Pervasive bioturbation of El Paso beds and fauna consisting of echinoderms, sponges, gastropods, trilobites, Nuia, Calathium, cephalopods, and algae plus minor brachiopods and Pulchrilamina indicate predominating shallow-subtidal environments. Low-energy platform environments, in which a large volume of micritic muds accumulated, were disturbed thousands of times by storms producing abundant thin, poorly washed biosparite, intrasparite, and intrasparrudite lenses.

  13. Modeling Visibility in the EL Paso del Norte Region

    NASA Astrophysics Data System (ADS)

    Fitzgerald, R. M.; Medina, R.; DuBois, D. W.; Novlan, D.

    2013-12-01

    Poor visibility is a subject of growing public concern throughout the U.S, and an active area of research. Its societal impacts in air quality, aviation transport and traffic are significant. Aerosols play a fundamental role in the attenuation of solar radiation, and also affect visibility. The scattering and extinction coefficients of aerosol particles in the Paso del Norte Region have been calculated using the T- matrix model in conjunction with a laser particle counter. Inter-comparison of the model's results of the scattering and absorption coefficients against the corresponding data from a Photoacustic Extinctiometer instrument (which measures in-situ absorption and scattering coefficients of aerosol particles) shows excellent agreement. In addition, the volume-weighted method is used to determine the composite index of refraction which is representative of the aerosols for the Paso del Norte Airshed to obtain information of the type of aerosol particles present in the Airshed. The Single Scattering Albedo has also been retrieved using our methodology to obtain further insight into the type of aerosols present on a given day. Finally, the Koschmieder equation has been used to calculate the visual range or visibility, and was correlated with the PM2.5 and PM10 particle concentration present in the Airshed. Our methodology will allow a better understanding of the size and type of aerosol particles that are most detrimental to the visibility for the Paso del Norte Region.

  14. The composition of wet deposition in El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Emmert, Sonny

    The composition of precipitation reflects the transport of particles from varying air mass source regions as well as input from local environmental and anthropogenic activities. Air research in El Paso, TX, U.S.A/Ciudad Juarez, Chihuahua, Mexico has been traditionally limited to studies of local inputs of air pollution; no transition has been made to studying the scavenging, washout, and transport of pollutants by precipitation. The goal of this research project was to identify transported pollutants in precipitation, and determine if there were any health and ecological implications. The research investigated biological, chemical, and geological constituents in precipitation samples collected between September 2004 and October 2005. A variety of analysis techniques were used to determine composition of the precipitation. These techniques included bacterial and fungal plate counts, inductively coupled plasma/mass spectrometry, ion chromatography, transmission electron microscopy, scanning electron microscopy, and electron microprobe analysis. Samples were collected from an urban site in El Paso, Texas at the campus of the University of Texas at El Paso. Wet only samples were the target of the sample collection. Particulate matter <10 microns was correlated with fungal growth while particulate matter < 2.5 microns was correlated with bacterial growth in analyzed samples. Microscopy methods revealed new techniques in particle characterization, evidence of anthropogenic influence, and a wide variety of particle compositions. The ionic chemistry results reflected elevated levels of ions as well as an overall alkalinity of rainwater samples. Elemental analysis of the inorganic fraction suggested elevated enrichment of Phosphorus in the study area and possible ratios for transport identification of southwestern dust storms.

  15. Ground-water resources of the El Paso area, Texas

    USGS Publications Warehouse

    Sayre, Albert Nelson; Livingston, Penn Poore

    1945-01-01

    El Paso, Tex., and Ciudad Juarez, Chihuahua, Mexico, and the industries in -that area draw their water supplies from wells, most of which are from 600 to 800 feet deep. In 1906, the estimated average pumpage there was about 1,000,000 gallons a day, and by 1935 it had increased to 15,400,000 gallons a day. The water-bearing beds, consisting of sand and gravel interbedded wire clay, tie in the deep structural trough known as the Hueco bolson, between the Organ and Franklin Mountains on the west, the Hueco, Finlay, and Malone Mountains on the east, the Tularosa Basin on the north, and the mountain ranges of Mexico on the south. From the gorge above El Paso to that beginning near Fort Quitman, about 90 miles southeast .of El Paso, the Rio Grande has eroded a flat-bottomed, steepwalled valley, 6 to 8 miles wide and 225 to 350 feet deep. No other large drainage channels have been developed on the bolson. The valley is known as the El Paso Valley, and the uneroded upland part of the bolson is called the Mesa. In the lowest parts of the El Paso Valley, the water-table is nearly at the surface. The quality of the underground water in the valley varies greatly both vertically and laterally. To a depth of about 400 to 500 feet it is in general too highly mineralized for municipal use, but between about. 500 and 900 feet good water may be obtained from several beds. In the beds between 500 and 900 feet the water level in wells is in places as. much as 20 feet lower than that in the shallow beds. Beneath the Mesa the water level .varies from about 200 feet beneath the surface, where the ground elevation is least, to about 400 feet. where it is highest. The water beneath the Mesa in general is of satisfactory quality and contains less than 500 parts per million of dissolved solids. Two cones of depression in the water table have been formed by the pumping near El Paso--one m the vicinity of the Mesa well field, the other around the Montana well field in the valley. The water

  16. Short-term water consumption dynamics in El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Fullerton, Thomas M.; ElíAs, Arturo

    2004-08-01

    Time series analysis of water consumption patterns has been the subject of increasing attention in recent years. For many municipalities such efforts offer a means for developing potentially useful planning tools. Because data requirements are not extensive, model development is feasible for markets where information is limited. The work at hand examines the applicability of such a tool in El Paso, Texas, a growing metropolitan economy located in a semiarid region. Sample data are from January 1994 through December 2002. In addition to estimating a linear transfer function equation of water consumption in this city the model is subjected to a series of simulation benchmark tests.

  17. Summary of extensometric measurements in El Paso, Texas

    USGS Publications Warehouse

    Heywood, Charles E.

    2003-01-01

    Two counter-weighted-pipe borehole extensometers were installed on the left bank of the Rio Grande between El Paso, Texas, and Ciudad Juarez, Chihuahua, Mexico, in 1992. A shallow extensometer measures vertical compaction in the 6- to 100-meter aquifer-system depth interval. A deep extensometer measures vertical compaction in the 6- to 305-meter aquifer-system depth interval. Both extensometers are referenced to the same surface datum, which allows time-series differencing to determine vertical compaction in the depth interval between 100 and 305 meters. From April 2, 1993, through June 13, 2002, 1.6 centimeters of compaction occurred in the 6-to 305-m depth interval. Until February 1999, most aquifer-system compaction occurred in the deeper aquifer-system interval between 100 and 305 meters, from which ground water was extracted. After that time, compaction in the shallow interval from 6 to 100 meters was predominant and attained a maximum of 7.6 millimeters by June 13, 2002. Minor residual compaction is expected to continue; continued maintenance of the El Paso extensometers would document this process.

  18. Ozone studies in the Paso del Norte region

    NASA Astrophysics Data System (ADS)

    Becerra-Davila, Fernando

    The Paso del Norte region forms the largest contiguous bi-national conglomerate on the US-Mexico border. With a combined population of around 2 million inhabitants, the Paso del Norte region is isolated, more than 500 km away from the nearest urban area of comparable size, thus making it an ideal location for air quality studies of an isolated urban environment. The meteorological conditions leading to a high ozone episode in this region, such as the historical ozone episode of June 2006, are analyzed. It is well known that stagnation and minimal winds, high temperatures, and pressure ridges over the region are conducive to high ozone episodes. In addition, the planetary boundary height is studied to understand its impact on high ozone episodes. Several studies report that ground level ozone non-attainment regulations could be caused not only by local emissions, but also by atmospheric transport. In this work the atmospheric advection of pollutants into the region is analyzed using HYSPLIT backward trajectories. Furthermore, a novel backward trajectory clustering technique is implemented for the summer of 2006. The "ozone weekend effect" (OWE) is a phenomenon by which in some geographical regions ambient ozone concentrations tend to be higher on weekends than on weekdays, despite the lower emissions of ozone precursors during those days. The observed local OWE has never previously been studied in terms of the photolysis rates of four of the main ozone precursors. In this research a novel method that allows the calculation of actinic fluxes, photolysis frequencies and photolysis rates with a high degree of accuracy and reliability has been developed. This method utilizes a combination of the experimental data available for this region in conjunction with a radiative transfer model (TUV model). Three weekend-weekday cases during summers 2006, 2009 and 2010 are studied in this work. In this research, the photolysis impact on the local OWE is studied. The results

  19. ATMOSPHERIC VOLATILE ORGANIC COMPOUND MEASUREMENTS DURING THE 1996 PASO DEL NORTE OZONE STUDY

    EPA Science Inventory

    Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US (El Paso) and Mexican (Ciudad Juarez) side of the border during a six-week period of the 1996 Paso del Norte Ozone Study. Samples were collected at five...

  20. Evaluation of Academic Policy Formulation and Implementation Transmountain Early College High School, El Paso, Texas

    ERIC Educational Resources Information Center

    Heidemann, Virginia Margaret

    2010-01-01

    Transmountain Early College High School (TMECHS) opened in August 2008, created by a partnership between the El Paso Community College (EPCC) and the El Paso Independent School District (EPISD), and supported in its conceptualization, start-up, and first few years operation by grant funding and guidance from the Texas High School Project (THSP)…

  1. 78 FR 58049 - Proposed Establishment of the Adelaida District, Creston District, El Pomar District, Paso Robles...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-20

    ..., at 74 FR 3425). Overview of the Paso Robles Viticultural Area The Paso Robles viticultural area... with Monterey County (see T.D. ATF-148, published in the Federal Register on October 4, 1983, at 48 FR....D. ATF-377, published in the Federal Register on June 13, 1996, at 61 FR 29952); and, as noted...

  2. 75 FR 70225 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... Energy Regulatory Commission El Paso Natural Gas Company; Notice of Application November 9, 2010. Take notice that on October 29, 2010, El Paso Natural Gas Company (EPNG), P.O. Box 1087, Colorado Springs... Natural Gas Act (NGA) and Rule 207(a)(5) of the Commission's regulations, requesting the...

  3. 77 FR 3757 - El Paso Natural Gas Company; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-25

    ... Energy Regulatory Commission El Paso Natural Gas Company; Notice of Application Take notice that on January 5, 2012, El Paso Natural Gas Company (EPNG), Post Office Box 1087, Colorado Springs, Colorado 80944 filed an application in the above referenced docket pursuant to section 7(b) of the Natural...

  4. Titanium Mass-Balance Analysis of Paso Robles Soils: Elemental Gains and Losses as Affected by Acid Alteration Fluids

    NASA Astrophysics Data System (ADS)

    Sutter, B.; Ming, D. W.

    2010-03-01

    Titanium mass-balance analysis of Paso Robles soils indicated elemental gains as supplied by sulfuric acid alteration fluids. This suggests that open-system dissolution processes have operated in the Paso Robles soils.

  5. DELIVERING TIMELY AIR QUALITY, TRAFFIC, AND WEATHER INFORMATION TO YOUR COMMUNITY/THE PASO DEL NORTE ENVIRONMENTAL MONITORING PROJECT

    EPA Science Inventory

    EPA has developed a technology transfer handbook for the EMPACT Paso del Norte Project. The EMPACT Paso del Norte Environmental Monitoring Project is a mobile vehicle emissions project that involves the international community of El Paso, TX; Sundland Park, NM; and Juarez, Mexico...

  6. 77 FR 29629 - El Paso Natural Gas Company; Notice of Intent To Prepare an Environmental Assessment for the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-18

    ... transport natural gas to a new delivery interconnect with Tarahumara Pipeline at the United States/Mexico... Energy Regulatory Commission El Paso Natural Gas Company; Notice of Intent To Prepare an Environmental... construction and operation of facilities by El Paso Natural Gas Company (EPNG) in El Paso County, Texas....

  7. 40 CFR 81.82 - El Paso-Las Cruces-Alamogordo Interstate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false El Paso-Las Cruces-Alamogordo... Designation of Air Quality Control Regions § 81.82 El Paso-Las Cruces-Alamogordo Interstate Air Quality Control Region. The El Paso-Las Cruces-Alamogordo Interstate Air Quality Control Region (New...

  8. [Energy education exhibits for Insights El Paso Science Museum

    SciTech Connect

    Shubinski, R.

    1998-05-27

    The grant in question, DE-FG03-94ER75954, was awarded to Insights El Paso Science Museum to build key exhibits. These exhibits helped the Museum fulfill its mission to ``promote curiosity and stimulate interest by exploratory, entertaining, exciting, and participatory learning in a broad range of scientific disciplines to persons of all ages regionally and internationally.`` There are several current Board of Directors members who also were Board members during the grant period and who helped construct some of the exhibits. Through speaking with them and reviewing minutes of Board meetings during 1994, it has been determined that seven of the ten proposed exhibits were constructed, with an eighth exhibit constructed as an alternative. Photos of seven of the exhibits and preliminary sketches of some are attached. Following is a list of the constructed exhibits: Hot or Cold, Give and Take, Conduction, Convection, Sources of Energy, Wind Generator, Solar Tracker, and Perpetual Motion.

  9. Ground-water resources of the Hueco Bolson, northeast of El Paso, Texas

    USGS Publications Warehouse

    Knowles, Doyle Blewer; Kennedy, Richard A.

    1958-01-01

    The Hueco Bolson is in the extreme western part of Texas and south- central New Mexico, covering parts of El Paso County, Tex., and Dona Ana and Otero Counties, N. Mex. Wells tapping the bolson deposits furnish the major part of the water supply for the city of El Paso, Ciudad Juarez, Fort Bliss, Biggs Air Force Base, and private industries. in the area. The progressively increasing demand for water made it obvious that a comprehensive investigation of the quantity and quality of water in storage in the entire Hueco Bolson would be essential for the proper planning of future water supplies. A test-drilling program was started in 1953, jointly sponsored by the city of El Paso, the United States Army, the United States Air Force, and the Texas Board of Water Engineers. The drilling was supervised by the United States Geological Survey.

  10. El Paso and White Sands area as seen from the Apollo 6 unmanned spacecraft

    NASA Technical Reports Server (NTRS)

    1968-01-01

    The El Paso and White Sands area are photographed from the Apollo 6 (Spacecraft 020/Saturn 502) unmanned space mission three hours and eight minutes after liftoff. North is toward top of picture. Near bottom center of picture is the El Paso-Ciudad Juarez, Mexico metropolitan area. At the top is the White Sands National Monument area. Note Rio Grande River on left side of picture. The snow-covered Sacremento Mountains are seen in the upper right corner. The altitude of the spacecraft when this photograph was taken was 115 nautical miles.

  11. Survey of methicillin-resistant Staphylococcus aureus strains from two hospitals in El Paso, Texas.

    PubMed

    O'Brien, Frances G; Lim, Tien Tze; Winnett, David C; Coombs, Geoffrey W; Pearson, Julie C; Delgado, Alejandro; Langevin, Mark J; Cantore, Stephanie A; Gonzalez, Leti; Gustafson, John E

    2005-06-01

    Seventy-one percent of 76 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from two medical centers in El Paso, Texas, represent three similar pulsed-field gel electrophoresis types. Overall, six pulsed-field types were identified represented by multilocus sequence/staphylococcal chromosomal cassette DNA mec (SCCmec) types: ST5-MRSA-II; ST36-MRSA-II; ST8 (untypeable SCCmec); and a newly described clonal cluster 8 strain, ST507-MRSA-IV. This study demonstrates the presence of multiple-antibiotic-resistant epidemic MRSA clones in El Paso.

  12. GIS-MODELED INDICATORS OF MOBILE SOURCE EMISSIONS AND ADVERSE HEALTH EFFECTS AMONG CHILDREN IN EL PASO, TEXAS, USA

    EPA Science Inventory

    The El Paso Children's Health Study has been a major collaborative effort by NHEERL and NERL scientists to examine the role of mobile source emissions in the development of allergies and asthma among 4th and 5th grade children in El Paso, TX. The purpose of this study was to det...

  13. CONTINUOUS MEASUREMENT OF FINE AND ULTRAFINE PARTICULATE MATTER, CRITERIA POLLUTANTS AND METEOROLOGICAL CONDITIONS IN URBAN EL PASO, TEXAS

    EPA Science Inventory

    Continuous measurements of aerosol size distributions were made in El Paso, TX, for a period in winter 1999. Size distribution measurements were performed at two urban locations in El Paso using two pairs of the scanning mobility particle sizer and the aerodynamic particle si...

  14. 78 FR 22540 - El Paso Natural Gas Company, L.L.C.; Notice of Petition for Declaratory Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-16

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission El Paso Natural Gas Company, L.L.C.; Notice of Petition for... Practice and Procedure, 18 CFR 385.207(a)(2)(2012), El Paso Natural Gas Company, L.L.C. (EPNG) submits...

  15. 78 FR 21934 - El Paso Natural Gas Company, L.L.C.; Notice of Request Under Blanket Authorization

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-12

    ... Authorization Take notice that on March 26, 2013, El Paso Natural Gas Company, L.L.C. (El Paso), P.O. Box 1087...., P.O. Box 1087, Colorado Springs, CO 80944, (719) 667-7517. Any person or the Commission's staff may... the Federal Energy Regulatory Commission, 888 First Street NE., Washington, DC 20426. Dated: April...

  16. GIS-MODELED INDICATORS OF MOBILE SOURCE EMISSIONS AND ADVERSE HEALTH EFFECTS AMONG CHILDREN IN EL PASO, TEXAS,USA*

    EPA Science Inventory

    The El Paso Children's Health Study has been a major collaborative effort by NHEERL and NERL scientists to examine the role of mobile source emissions in the development of allergies and asthma among 4th and 5th grade children in El Paso, TX. The purpose of this study was to dete...

  17. El Paso Community College Women in Technology End of the Year Report, 1998-1999.

    ERIC Educational Resources Information Center

    Di Benedetto, Victoria

    The Women in Technology (WIT) program at Texas' El Paso Community College (EPCC) was established to recruit women into nontraditional occupations, offering technical education, services to help retain women, and community outreach efforts to help change attitudes. This report describes outcomes for the 1998-99 fiscal year, focusing on six WIT…

  18. Comparing Values in Education on the U.S.-Mexican Border, El Paso and Ciudad Juarez.

    ERIC Educational Resources Information Center

    Rippberger, Susan; Staudt, Kathleen

    A three-year study examined attitudes toward education and public schools through behaviors in elementary schools in two United States-Mexican border towns, El Paso (Texas) and Ciudad Juarez (Mexico). It looked at curricular civic rituals such as the flag salute, and more covert normative training found in classroom organization and management…

  19. 77 FR 27774 - Kinder Morgan, Inc. and El Paso Corporation; Analysis of Proposed Agreement Containing Consent...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-11

    ... Register of May 7, 2012, in FR Doc. 2012-10870, on page 26760, the third column, first paragraph, correct... From the Federal Register Online via the Government Publishing Office FEDERAL TRADE COMMISSION Kinder Morgan, Inc. and El Paso Corporation; Analysis of Proposed Agreement Containing Consent Orders...

  20. Service Integration in Colorado: Connecting Programs To Provide Better Services in Mesa and El Paso Counties.

    ERIC Educational Resources Information Center

    Ragan, Mark

    Efforts to integrate the delivery of human service programs (HSP) in Colorado's El Paso County and Mesa County were examined through site visits and meetings with 34 members of HSP staff in both counties. The site visits confirmed that staff and management of HSP in both counties have implemented a series of client-centered processes to provide…

  1. Mediated Debate, Historical Framing, and Public Art: The Juan de Onate Controversy in El Paso

    ERIC Educational Resources Information Center

    Perez, Frank G.; Ortega, Carlos F.

    2008-01-01

    In 1988, the El Paso, Texas, city council accepted a proposal to build twelve statues of historically important individuals as part of a downtown revitalization initiative. Juan de Onate was selected as the centerpiece statue of the XII Travelers Memorial of the Southwest. The decision to honor the Spanish colonizer triggered a local controversy…

  2. Urban Impact of Dissolved Metals in the Paso del Norte Segment of the Rio Grande

    ERIC Educational Resources Information Center

    Freiwan, Sumayeh Ahmad

    2013-01-01

    The Paso del Norte segment of the Rio Grande experiences two seasons per year; the (wet) irrigation season and the (dry) non-irrigation season. The goal of this study was to improve the understanding of occurrence and contribution of dissolved metals in this region during the non-irrigation season. The objectives of this study were to (1) evaluate…

  3. Atmospheric volatile organic compound measurements during the 1996 Paso del Norte Ozone Study.

    PubMed

    Seila, R L; Main, H H; Arriaga, J L; Martínez, G; Ramadan, A B

    2001-08-10

    Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US (El Paso) and Mexican (Ciudad Juárez) side of the border during a six-week period of the 1996 Paso del Norte Ozone Study. Samples were collected at five sites, three on the US side and two on the Mexican side, during nine intensive operation days when high ozone levels were forecast for the area. Six other sites were sampled to characterize up-wind, down-wind and other emission sources. Samples for determining source profiles were collected for rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuels, and industrial manufacturing in Cd. Juárez and a refinery in El Paso. Most samples were collected in electro-polished stainless steel canisters for determination of C2 to C(10+) hydrocarbons by GC-FID. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites during aircraft flights and analyzed by HPLC. This paper presents the spatial and temporal characteristics of VOC species concentrations and compositions to examine the differences and similarities of the various locations and time periods. Overall surface, total non-methane hydrocarbon values ranged from 0.1 to 3.4 ppmC with the highest concentrations being recorded in the morning and evening at five vehicle-dominated sites, three in Cd. Juárez and two in El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cd. Juárez, were the most abundant hydrocarbons. The most abundant carbonyls were acetaldehyde, acetone and formaldehyde.

  4. Interaction and Relationship Between Groundwater and Surface Water at Keystone Heritage Park EL Paso Texas

    NASA Astrophysics Data System (ADS)

    Gonzalez, B.

    2012-12-01

    Belinda Gonzalez1, Joshua Villalobos1, Marissa Cameron 2 1Department of Geological Sciences, El Paso Community College, El Paso, TX 79925, USA 2Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968, USA beli_72764@yahoo.com Historically the floodplain of the Rio Grande River was dotted with shifting wetlands and ponds.The increasing population throughout the United States and Mexico has made it necessary to put the Rio Grande floodplain under till for cultivation. Along with cultivation, the river was channelized and dammed to prevent flooding and to stabilize the Mexico/U.S. border.The loss of wetland ecosystems in the area changed migration patterns of water fowl and destroyed priceless aquatic habitats.The area of our study, Keystone Heritage Park, is the last remaining open wetlands in El Paso County. Before efforts of restoration to reestablish wetlands associated with the Rio Grande can begin, there must be an in-depth, and complete, understanding of the surface and subsurface hydrological system which created and sustains this last remaining wetland. Studies of the wetland's soil properties and their effect on groundwater flow have indicated regions on the periphery of the wetlands where soils are saturated with moisture.These subsurface regions of saturated soils are semi-linear in shape and lead toward the wetland indicating that they are possible loci for groundwater flow for the wetland.These subsurface soil layers are possibly composed of mountain front alluvium that is being feed with meteoric water entering faults that bound the nearby Franklin Mountains.The primary goals of this study are 1) initiate a systematic data acquisition from 9 piezometers and 2 water level loggers of temporal variations in the depth of the groundwater due to regional pumping or rain fall and 2) generate a depth and TDS (Total Dissolved Solids) profile of the wetland pond to locate regions where groundwater maybe entering the lake.

  5. Atmospheric volatile organic compound measurements during the 1996 Paso del Norte Ozone Study.

    PubMed

    Seila, R L; Main, H H; Arriaga, J L; Martínez, G; Ramadan, A B

    2001-08-10

    Ambient air VOC samples were collected at surface air quality monitoring sites, near sources of interest, and aloft on the US (El Paso) and Mexican (Ciudad Juárez) side of the border during a six-week period of the 1996 Paso del Norte Ozone Study. Samples were collected at five sites, three on the US side and two on the Mexican side, during nine intensive operation days when high ozone levels were forecast for the area. Six other sites were sampled to characterize up-wind, down-wind and other emission sources. Samples for determining source profiles were collected for rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuels, and industrial manufacturing in Cd. Juárez and a refinery in El Paso. Most samples were collected in electro-polished stainless steel canisters for determination of C2 to C(10+) hydrocarbons by GC-FID. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites during aircraft flights and analyzed by HPLC. This paper presents the spatial and temporal characteristics of VOC species concentrations and compositions to examine the differences and similarities of the various locations and time periods. Overall surface, total non-methane hydrocarbon values ranged from 0.1 to 3.4 ppmC with the highest concentrations being recorded in the morning and evening at five vehicle-dominated sites, three in Cd. Juárez and two in El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cd. Juárez, were the most abundant hydrocarbons. The most abundant carbonyls were acetaldehyde, acetone and formaldehyde. PMID:11523535

  6. Hydrocarbon source apportionment for the 1996 Paso del Norte Ozone Study.

    PubMed

    Fujita, E M

    2001-08-10

    The 1996 Paso del Norte (PdN) ozone study was conducted to improve current understanding of the significant meteorological and air quality processes that lead to high concentrations of ozone in El Paso, Texas (USA) and Ciudad Juárez, Chihuahua (Mexico). Two-hour canister samples were collected five times daily at 05.00-07.00 h, 07.00-09.00 h, 09.00-11.00 h, 11.00-13.00 h, and 15.00-17.00 h MST during intensive study periods at one urban and one rural site on each side of the border. An automated gas chromatograph was operated at one site in central El Paso. Source profiles (the fractional chemical composition of emissions) from motor vehicles, gasoline, liquefied petroleum gas, and commercial natural gas were combined with source profiles from other studies for input to the Chemical Mass Balance (CMB) receptor model to apportion the measured non-methane hydrocarbons (NMHC) to sources. On-road vehicle emissions accounted for one-half to two-thirds of the NMHC in Ciudad Juárez and El Paso with the highest contributions occurring during the morning and afternoon commute periods. Emissions from diesel exhaust contributed approximately 2-3% of NMHC in Ciudad Juárez and less than 2% in El Paso. The average sum of liquid gasoline and gasoline vapor increased during the day in Ciudad Juárez from 2% at 06.00 h to approximately 12% at 16.00 h. Diurnal and day-of-the-week patterns in the liquid gasoline contributions are essentially identical to the corresponding patterns for motor vehicle exhaust, which suggest that a large fraction of the liquid gasoline contribution may be associated with tailpipe emissions rather than evaporative emissions from motor vehicles or industrial sources. Including the sum of the two sources put the upper limit for tailpipe contributions at 60-70% of NMHC. PMID:11516134

  7. Titanium Mass-balance Analysis of Paso Robles Soils: Elemental Gains and Losses as Affected by Acid Alteration Fluids

    NASA Technical Reports Server (NTRS)

    Sutter, Brad; Ming, Douglas W.

    2010-01-01

    The Columbia Hills soils have been exposed to aqueous alteration in alkaline [1] as well as acid conditions [2,3]. The Paso Robles class soils are bright soils that possess the highest S concentration of any soil measured on Mars [2]. Ferric-sulfate detection by Moessbauer analysis indicated that acid solutions were involved in forming these soils [4]. These soils are proposed to have formed by alteration of nearby rock by volcanic hydrothermal or fumarolic activity. The Paso Robles soils consist of the original Paso Robles-disturbed-Pasadena (PR-dist), Paso Robles- PasoLight (PR-PL), Arad-Samra, Arad-Hula, Tyrone- Berker Island1 and Tyrone-MountDarwin [2 ,3. ]Chemical characteristics indicate that the PR-dist and PR-PL soils could be derived from acid weathering of local Wishstone rocks while the Samra and Hula soils are likely derived from local Algonquin-Iroquet rock [3]. The Paso Robles soils were exposed to acidic sulfur bearing fluids; however, little else is known about the chemistry of the alteration fluid and its effects on the alteration of the proposed parent materials. The objectives of this work are to conduct titanium normalized mass-balance analysis to1) assess elemental gains and losses from the parent materials in the formation of the Paso Robles soils and 2) utilize this information to indicate the chemical nature of the alteration fluids.

  8. PACES Participation in Educational Outreach Programs at the University of Texas at El Paso

    NASA Technical Reports Server (NTRS)

    Dodge, Rebecca L.

    1997-01-01

    The University of Texas at El Paso (UTEP) is involved in several initiatives to improve science education within the El Paso area public schools. These include outreach efforts into the K- 12 classrooms; training programs for in-service teachers; and the introduction of a strong science core curricula within the College of Education. The Pan American Center for Earth and Environmental Studies (PACES), a NASA-funded University Research Center, will leverage off the goals of these existing initiatives to provide curriculum support materials at all levels. We will use currently available Mission to Planet Earth (MTPE) materials as well as new materials developed specifically for this region, in an effort to introduce the Earth System Science perspective into these programs. In addition, we are developing curriculum support materials and classes within the Geology and Computer Departments, to provide education in the area of remote sensing and GIS applications at the undergraduate and graduate levels.

  9. Geoseismic issues considered for design of the Samalayuca pipeline, El Paso County, Texas

    SciTech Connect

    Keaton, J.R.; Beckwith, G.H.; Medina, O.

    1995-12-31

    The Samalayuca, Pipeline is a proposed 20-inch-diameter natural gas pipeline extending approximately 21 miles from the Hueco Compressor Station on the El Paso Natural Gas main line to the International Boundary with Mexico near Clint, Texas, about 25 miles southeast of El Paso. The purpose of the project is to supply gas for power generation at a plant south of Cuidad Juarez, Chihuahua, Mexico. Geoseismic issues considered in the design of the Samalayuca Pipeline consisted of surface fault rupture, earthquake-induced landslides, and liquefaction-induced ground displacement.Faults represent two kinds of hazard to pipeline facilities: surface displacement and strong shaking. Earthquake-induced landslides and liquefaction require strong shaking to occur before these processes represent hazards to buried pipelines.

  10. Bacterial populations in the groundwater on the US-Mexico border in El Paso County, Texas.

    PubMed

    Mroz, R C; Pillai, S D

    1994-12-01

    In El Paso County, Texas, 73 domestic wells were sampled using a variety of selective media to determine the extent of bacterial contamination of the groundwater on the US side of the United States-Mexico border. Thirteen wells were contaminated by fecal coliforms, whereas other wells contained a variety of bacterial genera including some potential pathogens that normally would not be detected by standard methods of water testing.

  11. Composition and Formation of the "Paso Robles" Class Soils at Gusev Crater

    NASA Technical Reports Server (NTRS)

    Yen, A. S.; Morris, Richard V.; Gellert, R.; Clark, B. C.; Ming, Douglas W.; Klingelhoefer, G.; McCoy, T. J.; Schmidt, M. E.

    2007-01-01

    Light-toned, subsurface soil deposits have been excavated by the Mars Exploration Rover (MER) Spirit in six distinct locations along its traverse across the Columbia Hills of Gusev Crater. Samples at two of these sites have been analyzed in detail by the M ssbauer (MB) and Alpha Particle X-ray Spectrometers (APXS), providing information on iron mineralogy and elemental chemistry, respectively. These soils are referred to as "Paso Robles" class deposits.

  12. The Influence of Photolysis Rate Constants in Ozone Production for the Paso del Norte Region

    NASA Astrophysics Data System (ADS)

    Becerra, Fernando; Fitzgerald, Rosa

    2012-03-01

    In this research work we are focusing on understanding the relationship between photolysis rates and the photochemical ozone changes observed in the Paso del Norte region. The city of El Paso, Texas together with Ciudad Juarez, Mexico, forms the largest contiguous bi-national metropolitan area. This region suffers year-round ozone pollution events, and a better understanding is needed to mitigate them. Previous studies have found that ambient ozone concentrations tend to be higher on weekends rather than on weekdays, this phenomenon being referred to, as the ``weekend effect.'' If the ozone standard is exceeded more frequently on weekends, then this phenomenon must be considered in the design of ozone control strategies. In this work we investigate some of the most representative weekend ozone episodes at El Paso, TX, during the years 2009, 2010 and 2011 using the ozone photolysis rates. In this research the TUV radiative-transfer model is used to calculate the local photolysis rates and a UV MFRSR instrument is used to obtain experimental parameters. Seasonal variations and the weekday-weekend effect is studied. The results of this research will help to understand the underlying behavior of the photolysis rate constants when different atmospheric conditions are present.

  13. Winter season air pollution in El Paso-Ciudad Juarez. A review of air pollution studies in an international airshed

    SciTech Connect

    Einfeld, W.; Church, H.W.

    1995-03-01

    This report summarizes a number of research efforts completed over the past 20 years in the El Paso del Norte region to characterize pollution sources and air quality trends. The El Paso del Norte region encompasses the cities of El Paso, Texas and Ciudad Juarez, Chihuahua and is representative of many US-Mexico border communities that are facing important air quality issues as population growth and industrialization of Mexican border communities continue. Special attention is given to a group of studies carried out under special US Congressional funding and administered by the US Environmental Protection Agency. Many of these studies were fielded within the last several years to develop a better understanding of air pollution sources and trends in this typical border community. Summary findings from a wide range of studies dealing with such issues as the temporal and spatial distribution of pollutants and pollution potential from both stationary and mobile sources in both cities are presented. Particular emphasis is given to a recent study in El Paso-Ciudad Juarez that focussed on winter season PM{sub 10} pollution in El Paso-Ciudad Juarez. Preliminary estimates from this short-term study reveal that biomass combustion products and crustal material are significant components of winter season PM{sub 10} in this international border community.

  14. The 1996 Paso del Norte Ozone Study: analysis of meteorological and air quality data that influence local ozone concentrations.

    PubMed

    MacDonal, C P; Roberts, P T; Main, H H; Dye, T S; Coe, D L; Yarbrough, J

    2001-08-10

    The 1996 Paso del Norte Ozone Study and subsequent data analyses were implemented to develop an understanding of the chemical and physical processes which lead to high concentrations of ozone in the Paso del Norte study area which includes El Paso County, Texas, Sunland Park, New Mexico, and Ciudad Juárez, Mexico. Both the data and data analysis results are being used to support photochemical grid modeling. El Paso County and Sunland Park fail to meet the National Ambient Air Quality Standard (NAAQS) for ozone, and neighboring Ciudad Juárez fails to meet the Mexican ambient standard for ozone. This paper summarizes the measurement campaigns of the 1996 Paso del Norte Ozone Study and the findings and conclusions that arose from subsequent data analyses. Data analyses showed that high ozone concentrations resulted from a combination of conditions, including high surface temperatures, strong sunlight with few clouds, light surface winds and high concentrations of ozone precursors at ground level in the morning, and slow convective boundary layer (CBL) growth. Synoptic-scale meteorological conditions observed during high ozone episodes included an aloft high-pressure system and aloft warming. Aloft carryover of ozone and ozone precursors did not significantly contribute to high concentrations of ozone at the surface.

  15. Results from an investigation of the integration of wind energy into the El Paso Electric grid system

    SciTech Connect

    Moroz, E.M.; Parks, N.J.; Swift, A.H.; Traichal, P.A.

    1997-12-31

    This paper documents some preliminary results from an evaluation of the costs and benefits to be gained from the integration of wind generated electricity into the El Paso Electric grid system. The study focused on the utilization of the considerable known wind potential of the Guadalupe/Delaware Mountains region, but also looked at other energetic wind resources within 15 miles of El Paso Electric`s Grid. The original project`s goal was to identify the added value of wind in terms of jobs, line support, risk reduction etc., that wind energy could bring to El Paso Electric. Although these goals have not yet been achieved the potential for water savings and reductions in gaseous emissions have been documented. Thus this paper focuses mainly on the water consumption and criteria pollutant emissions that could be avoided by adding wind energy to El Paso Electric`s generation mix. Preliminary data from a renewables attitude survey indicates that, from the 338 respondents, there is overwhelming public support for utilizing such renewable sources of electricity. This case study, which should be of direct relevance to the arid southwestern states and beyond, was sponsored by the Environmental Protection Agency (EPA) and conducted in cooperation with El Paso Electric.

  16. Investigation of Soil Permeability and Hydrological Properties of Flood Plain Deposits of the Rio Grande in EL Paso TX

    NASA Astrophysics Data System (ADS)

    Schacht, D.; Jin, L.; Doser, D. I.

    2013-12-01

    The various soil types within the flood plains of Rio Grande in El Paso 's Lower Valley have long been utilized by local farmers. These soils are typically more conducive to farming than the more recent (Pliocene) sandy soils outside of the flood plain region. This project will explore the various properties of these soils types such as their grain size, depths, extent, and hydrological conductivity utilizing various geophysical and geochemical methods. The study site is located in El Paso 's Lower Valley and is situated in an actively farmed area. Soil maps from the Natural Resource Conservation Service (NRCS) and variations in vegetation growth will help delineate locations of soil types in the study area. The information that will be collected will produce baseline data to help track expected seasonal variations in the soil's moisture content and in the depth of the local water table. This project represents a collaboration between El Paso Community College's and the University of Texas at El Paso's Departments of Geological Sciences as a means for students majoring in Geological Sciences at El Paso Community College to gain hands on experience in researching geological issues through partnerships with their future institution and faculty.

  17. Associations between urban air pollution and pediatric asthma control in El Paso, Texas.

    PubMed

    Zora, Jennifer E; Sarnat, Stefanie Ebelt; Raysoni, Amit U; Johnson, Brent A; Li, Wen-Whai; Greenwald, Roby; Holguin, Fernando; Stock, Thomas H; Sarnat, Jeremy A

    2013-03-15

    Exposure to traffic-related pollutants poses a serious health threat to residents of major urban centers around the world. In El Paso, Texas, this problem is exacerbated by the region's arid weather, frequent temperature inversions, heavy border traffic, and an aged, poorly maintained vehicle fleet. The impact of exposure to traffic pollution, particularly on children with asthma, is poorly understood. Tracking the environmental health burden related to traffic pollution in El Paso is difficult, especially within school microenvironments, because of the lack of sensitive environmental health indicator data. The Asthma Control Questionnaire (ACQ) is a survey tool for the measurement of overall asthma control, yet has not previously been considered as an outcome in air pollution health effect research. We conducted a repeated measure panel study to examine weekly associations between ACQ scores and traffic- and non-traffic air pollutants among asthmatic schoolchildren in El Paso. In the main one- and two-pollutant epidemiologic models, we found non-significant, albeit suggestive, positive associations between ACQ scores and respirable particulate matter (PM10), coarse particulate matter (PM10-2.5), fine particulate matter (PM2.5), black carbon (BC), nitrogen dioxide (NO2), benzene, toluene, and ozone (O3). Notably, associations were stronger and significant for some subgroups, in particular among subjects taking daily inhaled corticosteroids. This pattern may indicate heightened immune system response in more severe asthmatics, those with worse asthma "control" and higher ACQ scores at baseline. If the ACQ is appropriately used in the context of air pollution studies, it could reflect clinically measurable and biologically relevant changes in lung function and asthma symptoms that result from poor air quality and may increase our understanding of how air pollution influences asthma exacerbation.

  18. Obstetric emergencies at the United States–Mexico border crossings in El Paso, Texas

    PubMed Central

    McDonald, Jill A.; Rishel, Karen; Escobedo, Miguel A.; Arellano, Danielle E.; Cunningham, Timothy J.

    2015-01-01

    Objective To describe the frequency, characteristics, and patient outcomes for women who accessed Emergency Medical Services (EMS) for obstetric emergencies at the ports of entry (POE) between El Paso, Texas, United States of America, and Ciudad Juárez, Chihuahua, Mexico. Methods A descriptive study of women 12–49 years of age for whom an EMS ambulance was called to an El Paso POE location from December 2008–April 2011 was conducted. Women were identified through surveillance of EMS records. EMS and emergency department (ED) records were abstracted for all women through December 2009 and for women with an obstetric emergency through April 2011. For obstetric patients admitted to the hospital, additional prenatal and birth characteristics were collected. Frequencies and proportions were estimated for each variable; differences between residents of the United States and Mexico were tested. Results During December 2008–December 2009, 47.6% (68/143) of women receiving EMS assistance at an El Paso POE had an obstetric emergency, nearly 20 times the proportion for Texas overall. During December 2008–April 2011, 60.1% (66/109) of obstetric patients with ED records were admitted to hospital and 52 gave birth before discharge. Preterm birth (23.1%; No. = 12), low birth weight (9.6%; No. = 5), birth in transit (7.7%; No. = 4), and postpartum hemorrhage (5.8%; No. = 3) were common; fewer than one-half the women (46.2%; No. = 24) had evidence of prenatal care. Conclusions The high proportion of obstetric EMS transports and high prevalence of complications in this population suggest a need for binational risk reduction efforts. PMID:25915011

  19. Resource investigation of low- and moderate-temperature geothermal areas in Paso Robles, California

    SciTech Connect

    Campion, L.F.; Chapman, R.H.; Chase, G.W.; Youngs, L.G.

    1983-01-01

    Ninety-eight geothermal wells and springs were identified and plotted, and a geologic map and cross sections were compiled. Detailed geophysical, geochemical, and geological surveys were conducted. The geological and geophysical work delineated the basement highs and trough-like depressions that can exercise control on the occurrence of the thermal waters. The Rinconada fault was also evident. Cross sections drawn from oil well logs show the sediments conforming against these basement highs and filling the depressions. It is along the locations where the sediments meet the basement highs that three natural warm springs in the area occur. Deep circulation of meteoric waters along faults seems to be a reasonable source for the warm water. The Santa Margarita, Pancho Rico, and Paso Robles Formations would be the first permeable zones that abut the faults through which water would enter. Temperatures and interpretation of well logs indicate the warmest aquifer at the base of the Paso Robles Formation. Warm water may be entering higher up in the section, but mixing with water from cooler zones seems to be evident. Geothermometry indicates reservoir temperatures could be as high as 91/sup 0/C (196/sup 0/F).

  20. Meteorological Simulations of Ozone Episode Case Days during the 1996 Paso del Norte Ozone Study

    SciTech Connect

    Brown, M.J.; Costigan, K.; Muller, C.; Wang, G.

    1999-02-01

    Meteorological simulations centered around the border cities of El Paso and Ciudad Juarez have been performed during an ozone episode that occurred on Aug. 13,1996 during the 1996 Paso del Norte Ozone Study field campaign. Simulations were petiormed using the HOTMAC mesoscale meteorological model using a 1,2,4, and 8 km horizontal grid size nested mesh system. Investigation of the vertical structure and evolution of the atmospheric boundary layer for the Aug. 11-13 time period is emphasized in this paper. Comparison of model-produced wind speed profiles to rawirisonde and radar profiler measurements shows reasonable agreement. A persistent upper-level jet was captured in the model simulations through data assimilation. In the evening hours, the model was not able to produce the strong wind direction shear seen in the radar wind profiles. Based on virtual potential temperature profile comparisons, the model appears to correctly simulate the daytime growth of the convective mixed layer. However, the model underestimates the cooling of the surface layer at night. We found that the upper-level jet significantly impacted the turbulence structure of the boundary layer, leading to relatively high turbulent kinetic energy (tke) values aloft at night. The model indicates that these high tke values aloft enhance the mid-morning growth of the boundary layer. No upper-level turbulence measurements were available to verify this finding, however. Radar profiler-derived mixing heights do indicate relatively rapid morning growth of the mixed layer.

  1. Ambient Concentrations of Metabolic Disrupting Chemicals and Children’s Academic Achievement in El Paso, Texas

    PubMed Central

    Clark-Reyna, Stephanie E.; Grineski, Sara E.; Collins, Timothy W.

    2016-01-01

    Concerns about children’s weight have steadily risen alongside the manufacture and use of myriad chemicals in the US. One class of chemicals, known as metabolic disruptors, interfere with human endocrine and metabolic functioning and are of specific concern to children’s health and development. This article examines the effect of residential concentrations of metabolic disrupting chemicals on children’s school performance for the first time. Census tract-level ambient concentrations for known metabolic disruptors come from the US Environmental Protection Agency’s National Air Toxics Assessment. Other measures were drawn from a survey of primary caretakers of 4th and 5th grade children in El Paso Independent School District (El Paso, TX, USA). A mediation model is employed to examine two hypothetical pathways through which the ambient level of metabolic disruptors at a child’s home might affect grade point average. Results indicate that concentrations of metabolic disruptors are statistically significantly associated with lower grade point averages directly and indirectly through body mass index. Findings from this study have practical implications for environmental justice research and chemical policy reform in the US. PMID:27598179

  2. Increasing Minority Participation and Matriculation in the Geosciences at El Paso Community College

    NASA Astrophysics Data System (ADS)

    Villalobos, J. I.

    2011-12-01

    Community colleges currently serve 44% of all undergraduate students and 45% of all of all first time freshmen in the US. Hispanics now constitute 15% of the general population and 19% of the college population in the US. This increase has led to more institutions emerging as HSI (Hispanic Serving Institution) by the federal government. These facts illustrate the potential community colleges hold to encourage STEM (Science Technology Engineering and Math) majors to minorities as well as non-minorities. But the reality is the number of STEM degrees awarded at community colleges has not followed the same trends in enrollment. El Paso Community College (EPCC) currently enrolls 27,000 students with 85% of the student body being Hispanic. More than 130 programs of study are offered including an Associate of Science degree in Geological Sciences. Over the past three years we have implemented several initiatives in our effort to increase the number of Geological Science (GS) majors at EPCC. These efforts are aimed to decrease attrition rates of science majors by; streamlining the GS degree plan along with the process of course registration, introduce field-based research projects to students to allow hands on research, develop a work relationships with students and university faculty, increase the number of geology courses offered at EPCC including a field-based capstone course (GEOL 2407- Geological Field Methods), and strengthening the educational-bridge between the geological science departments of EPCC and University of Texas at El Paso.

  3. Hydrothermal processes at Gusev Crater: An evaluation of Paso Robles class soils

    USGS Publications Warehouse

    Yen, A. S.; Morris, R.V.; Clark, B. C.; Gellert, Ralf; Knudson, A.T.; Squyres, S.; Mittlefehldt, D. W.; Ming, D. W.; Arvidson, R.; McCoy, T.; Schmidt, M.; Hurowitz, J.; Li, R.; Johnson, J. R.

    2008-01-01

    The Mars Exploration Rover Spirit analyzed multiple occurrences of sulfur-rich, light-toned soils along its traverse within Gusev Crater. These hydrated deposits are not readily apparent in images of undisturbed soil but are present at shallow depths and were exposed by the actions of the rover wheels. Referred to as 'Paso Robles' class soils, they are dominated by ferric iron sulfates, silica, and Mg-sulfates. Ca-sulfates, Ca-phosphates, and other minor phases are also indicated in certain specific samples. The chemical compositions are highly variable over both centimeter-scale distances and between the widely separated exposures, but they clearly reflect the elemental signatures of nearby rocks. The quantity of typical basaltic soil mixed into the light-toned materials prior to excavation by the rover wheels is minimal, suggesting negligible reworking of the deposits after their initial formation. The mineralogy, geochemistry, variability, association with local compositions, and geologic setting of the deposits suggest that Paso Robles class soils likely formed as hydrothermal and famarolic condensates derived from magma degassing and/ or oxidative alteration of crustal iron sulfide deposits. Their occurrence as unconsolidated, near-surface soils permits, though does not require, an age that is significantly younger than that of the surrounding rocks. Copyright 2008 by the American Geophysical Union.

  4. Preliminary isostatic residual gravity anomaly map of Paso Robles 30 x 60 minute quadrangle, California

    USGS Publications Warehouse

    McPhee, D.K.; Langenheim, V.E.; Watt, J.T.

    2011-01-01

    This isostatic residual gravity map is part of an effort to map the three-dimensional distribution of rocks in the central California Coast Ranges and will serve as a basis for modeling the shape of basins and for determining the location and geometry of faults within the Paso Robles quadrangle. Local spatial variations in the Earth\\'s gravity field, after accounting for variations caused by elevation, terrain, and deep crustal structure reflect the distribution of densities in the mid- to upper crust. Densities often can be related to rock type, and abrupt spatial changes in density commonly mark lithological or structural boundaries. High-density rocks exposed within the central Coast Ranges include Mesozoic granitic rocks (exposed northwest of Paso Robles), Jurassic to Cretaceous marine strata of the Great Valley Sequence (exposed primarily northeast of the San Andreas fault), and Mesozoic sedimentary and volcanic rocks of the Franciscan Complex [exposed in the Santa Lucia Range and northeast of the San Andreas fault (SAF) near Parkfield, California]. Alluvial sediments and Tertiary sedimentary rocks are characterized by low densities; however, with increasing depth of burial and age, the densities of these rocks may become indistinguishable from those of older basement rocks.

  5. The displaced eugeoclinal rocks in the El Paso Mountains and northern Mojave Desert: A Triassic sliver

    SciTech Connect

    Miller, J.S.; Glazner, A.F. . Dept. of Geology); Walker, J.D.; Martin, M.W. . Dept. of Geology)

    1993-04-01

    Many workers have drawn attention to the displaced eugeoclinal rocks in the northern Mojave Desert and El Paso Mountains and their importance in models for the development of an active continental margin in the western Cordillera. Existing models can generally for either strike-slip juxtaposition or thrust emplacement. New field data, U-Pb zircon geochronology, and isotopic data for metasedimentary rocks and plutons in the northern Mojave Desert and El Paso Mountains shed light on the timing and mechanism of emplacement of the eugeoclinal allocthon. The observations and data above indicate that Early Triassic plutons in the northern Mojave Desert came through oceanic lithosphere but later Jurassic plutons intercepted continental lithosphere. The authors suggest a model where eugeoclinal rocks were deposited on oceanic crust which was initially brought southward along a strike-slip fault and later thrust eastward over the cratonal assemblage. Permian thrusting is incompatible with their data and observations. Intrusion of lower Triassic strata by Early Triassic plutons in the Lane Mountain area permits some Early Triassic thrusting but the oceanic affinity of the plutons implies that thrusting did not involve continental lithosphere.

  6. Meteorological simulations of boundary-layer structure during the 1996 Paso del Norte Ozone Study.

    PubMed

    Brown, M J; Muller, C; Wang, G; Costigan, K

    2001-08-10

    Meteorological simulations centered around the border cities of El Paso and Ciudad Juárez have been performed during an ozone episode that occurred on August 13, 1996 during the 1996 Paso del Norte Ozone Study field campaign. Simulations were performed using the HOTMAC boundary-layer meteorological model using a 1, 2, 4 and 8-km horizontal grid size nested mesh system. Investigation of the vertical structure and evolution of the atmospheric boundary layer for the August 12-14 time period is emphasized in this paper due to its suspected importance in precipitating the ozone episode [Sci Total Environ (2001)]. This period was characterized by a slowly-evolving high pressure system over the region, a persistent upper-level jet at 2500-3500 m above ground level (agl), deep daytime mixed layer heights of 3500 m depth and unusually deep nighttime stable layers extending up to 2500 m above the ground. The fact that the boundary-layer growth stalled on the morning of August 13 relative to that on August 12 has been suggested as a possible reason for the ozone episode on the 13th. In addition, relatively weak surface-level winds were measured on August 13. Using both model results and experimental data we hypothesize explanations for the slower mixed-layer growth on the morning of the 13th and the stronger surface-level winds found on the 12th and 14th.

  7. Ambient Concentrations of Metabolic Disrupting Chemicals and Children's Academic Achievement in El Paso, Texas.

    PubMed

    Clark-Reyna, Stephanie E; Grineski, Sara E; Collins, Timothy W

    2016-01-01

    Concerns about children's weight have steadily risen alongside the manufacture and use of myriad chemicals in the US. One class of chemicals, known as metabolic disruptors, interfere with human endocrine and metabolic functioning and are of specific concern to children's health and development. This article examines the effect of residential concentrations of metabolic disrupting chemicals on children's school performance for the first time. Census tract-level ambient concentrations for known metabolic disruptors come from the US Environmental Protection Agency's National Air Toxics Assessment. Other measures were drawn from a survey of primary caretakers of 4th and 5th grade children in El Paso Independent School District (El Paso, TX, USA). A mediation model is employed to examine two hypothetical pathways through which the ambient level of metabolic disruptors at a child's home might affect grade point average. Results indicate that concentrations of metabolic disruptors are statistically significantly associated with lower grade point averages directly and indirectly through body mass index. Findings from this study have practical implications for environmental justice research and chemical policy reform in the US. PMID:27598179

  8. Depositional environments and diagenesis of El Paso Group, Southern Hueco Mountains, Hudspeth County, Texas

    SciTech Connect

    Aluka, I.J.

    1988-01-01

    The El Paso Group, a predominantly carbonate sequence, overlies the time-transgressive Cambrian-Ordovician Bliss Sandstone, and underlies the Upper Ordovician Montoya Group. The sequence contains three units (in ascending order): lower limestone, middle cherty limestone, and upper dolomite. The units were deposited in a shelf lagoon with open and restricted circulation, subtidal and intertidal environments. Deposition in these environments is indicated by the presence of land-derived clastics (silt- and sand-size quartz), abundant pellets, micrite, a variety of textures (mudstones to grainstones), algal structures, cross-bedding, and inter-fingering of clastics with limestones due to sedimentary offlap and onlap resulting in clastic progradation west and east from the Diablo platform (the clastic source). The upper unit was, in part, deposited in a supratidal environment, as shown by the presence of abundant dolomite. In addition, the rocks of the El Paso Group were affected by various diagenetic processes, including dolomitization (supratidal dolomitization and dolomitization through meteoric mixing) and silicification, as exemplified by chert nodules and lenses and the presence of silica in intragranular voids and as intrapelmatozoan infillings. Silica partially replaced gastropods, cephalopods, and pelmatozoan ossicles. Recrystallization (aggrading neomorphism) converted carbonate muds into microspar and sparry calcite. Stylolitization (microstylolites and sutured stylolites) affected the rocks as indicated by the presence of iron oxides along the stylolites. The rocks were also affected by pyritization as shown silicified bioclasts.

  9. Summary of hydrologic information in the El Paso, Texas, area, with emphasis on ground-water studies, 1903-80

    USGS Publications Warehouse

    White, D.E.

    1983-01-01

    Flow in the Rio Grande is diverted for crop irrigation in the United States and the Republic of Mexico, and for limited municipal supply in El Paso. The flow is regulated by releases from reservoirs in New Mexico and varies widely in both quantity and quality (dissolved-solids concentrations). During 1943-80, the flow at El Paso ranged from 57,481 acre-feet (71 cubic hectometers) in 1956 to 631,800 acre-feet (779 cubic hectometers) in 1943 and averaged about 317,000 acre-feet per year (391 cubic hectometers).

  10. Size-Time-Composition Resolved Study of Aerosols Across El Paso, Texas in Fall 2008

    NASA Astrophysics Data System (ADS)

    Cahill, T. A.; Gill, T. E.; Pingitore, N. E.; Olvera, H. A.; Clague, J. W.; Barnes, D. E.; Perry, K. D.; Li, W.; Amaya, M. A.

    2009-12-01

    Systematic variations in the absolute amounts, size and composition of airborne particulate matter (PM) across the El Paso, Texas metropolitan area may differentially impact the respiratory status (e.g., asthma) and overall health of the local population. To understand these variations, we collected size-time resolved samples of PM with DRUM samplers during a one-month period in late autumn 2008 at three sites along a NW-SE (roughly upwind-downwind) transect across El Paso’s airshed. The DRUM sampler is a rotating-drum impactor separating and collecting aerosols on Mylar strips mounted on the drums, in 8 size stages from 10 μm to <0.1 μm. DRUM strips are analyzed with 3-hr time resolution by β-gauge for mass and by synchrotron X-ray fluorescence for elemental composition. We collected samples at Santa Teresa, New Mexico (a minimally developed area NW of El Paso, at the edge of a sparsely-inhabited expanse of the Chihuahuan Desert), at the edge of the University of Texas- El Paso (UTEP) campus (in the urban core of El Paso), and at Socorro, Texas (a suburban area in the valley of the Rio Grande, SE of the urban core). Results illustrate sharp excursions in mass and element concentrations in aerosol-laden periods lasting from several hours to several days, associated with stagnant air, inversions, smoke events, dust/high wind/frontal passage, and/or daily traffic patterns, punctuated by several periods of reduced aerosol levels after Pacific frontal passages. Mass and absorption data show an increasing influence of carbonaceous (absorbing) aerosols with decreasing particle size <~1 μm, and increasing influence of mineral (scattering) aerosols with increasing particle size >~1 μm. Calcium/silicon ratios were high (>1), especially in coarser stages and during high wind events, reflecting wind erosion of the Chihuahuan Desert’s calcareous soils. Concentrations of chlorine, silicon, calcium, coarse potassium, and lead increased during high wind events, while

  11. GIS-modeled indicators of traffic-related air pollutants and adverse pulmonary health among children in El Paso, Texas, USA.

    EPA Science Inventory

    The El Paso Children?s Health Study examined 5,654 children enrolled in the El Paso, Texas public school district by questionnaire in 2001. Exposure measurements were first collected in the late fall of 1999. Then school-level and residence-level exposures to traffic-related air ...

  12. Variability in childhood allergy and asthma across ethnicity, language, and residency duration in El Paso, Texas: a cross-sectional study

    PubMed Central

    2009-01-01

    Background We evaluated the impact of migration to the USA-Mexico border city of El Paso, Texas (USA), parental language preference, and Hispanic ethnicity on childhood asthma to differentiate between its social and environmental determinants. Methods Allergy and asthma prevalence was surveyed among 9797 fourth and fifth grade children enrolled in the El Paso Independent School District. Parents completed a respiratory health questionnaire, in either English or Spanish, and a sub-sample of children received spirometry testing at their school. Here we report asthma and allergy outcomes across ethnicity and El Paso residency duration. Results Asthma and allergy prevalence increased with longer duration of El Paso residency independent of ethnicity and preferred language. Compared with immigrants who arrived in El Paso after entering first grade (18%), lifelong El Paso residents (68%) had more prevalent allergy (OR, 1.72; 95% CI, 1.32 - 2.24), prevalent asthma (OR, 1.75; 95% CI, 1.24 - 2.46), and current asthma (OR, 2.01; 95% CI, 1.37 - 2.95). Spirometric measurements (FEV1/FVC and FEF25-75) also declined with increasing duration of El Paso residency (0.16% and 0.35% annual reduction, respectively). Conclusion These findings suggest that a community-wide environmental exposure in El Paso, delayed pulmonary development, or increased health of immigrants may be associated with allergy and asthma development in children raised there. PMID:19995440

  13. A Study of Y.W.C.A. Services Performed for Pregnant and Parenting High School Students of El Paso from 1982 to 1985.

    ERIC Educational Resources Information Center

    Jackson, Ronald B.

    Questionnaires and interviews were used to study the effectiveness of programs provided for pregnant and parenting students by the Young Women's Christian Association (YWCA) of El Paso, Texas. The study focused on the School-Age Parent Center (SPC), established in 1974 by the El Paso Independent School District, and the YWCA programs and services…

  14. Early College High Schools Established from 2006 through 2008 in El Paso County, Texas: Discovering Factors Contributing to Hispanic Student Success

    ERIC Educational Resources Information Center

    Munoz, Maluka Dorotea

    2011-01-01

    The purpose of this study was to (a) identify factors contributing to the success of Hispanic students in four Early College High Schools (ECHSs) in El Paso County, (b) identify components of the ECHSs that can be realistically considered for implementation by administrators of larger public high schools in El Paso County, and (c) determine…

  15. Residential Exposure to Nighttime Retained Heat in the El Paso, Texas, USA Desert Metroplex

    NASA Astrophysics Data System (ADS)

    Amaya, M. A.; Mohammed, M.; Pingitore, N. E.; Aldouri, R. K.; Benedict, B. A.

    2013-12-01

    The urban heat island is a well recognized and extensively studied phenomenon that has accelerating importance resulting from two trends associated with world-wide population growth: increasing urbanization and global warming. Urbanization, particularly when unplanned and haphazard, changes such thermal parameters as albedo, surface roughness, and heat capacities of surface materials. Rapid urbanization in the contiguous El Paso, Texas, USA - Ciudad Juarez, Chihuahua, Mexico bi-national metroplex has produced an urban heat island that is warmer than the surrounding Chihuahuan desert (temperature: 35-40 C summer; high elevation: 600-1675 m; rainfall: less than 250 mm annual). Despite the extensive literature on the urban heat island, little is known about urban nighttime land surface temperatures. We employed infrared satellite imaging to establish the variation of nighttime neighborhood surface temperatures across the city of El Paso, as well as all of El Paso County. The underlying purpose of our continuing investigation is to evaluate the geography of morbidity risk: are different neighborhoods at different risk of high nighttime temperatures. Those risks can include heat stress, and irritability and sleep deprivation, with possible resultant violence. Heat exposure at night is significant because residents are at home and 90% of El Pasoans do not have 'refrigerated' air conditioning, but instead have evaporative coolers, which are less expensive to own and operate, but are less effective since they raise the humidity of the partially cooled air. Our geographically weighted regression model showed that both day and nighttime land surface temperatures correlated with the normalized difference vegetation index, population density, and albedo. The association with the index and albedo was stronger during the daytime and with population density during the nighttime. Vegetation (negative) and population density (positive) were the dominant temperature drivers, with

  16. Geospatial Distribution of Heavy Metals in an Urban Soil, El Paso, Texas, USA

    NASA Astrophysics Data System (ADS)

    Amaya, M. A.; Elkekli, A. R.; Clague, J. W.; Grimida, S. E.; Pingitore, N. E., Jr.

    2014-12-01

    Some 500 city blocks were selected randomly via population-based stratification. Equal volumes of soil collected from the public space (where present) in front of each house on a block yielded a composite sample. Composites provide neighborhood level "smoothing" relative to sampling many individual houses, and greatly decrease laboratory effort/cost. In the laboratory 10 g of soil were comminuted in a ceramic ball mill, mixed with cellulose/ paraffin binder, and pressed (20 tons) into a pellet. A Panalytical Epsilon5 EDS-XRF, using 8 sequential secondary target conditions and 12 NIST and USGS multi-element rock standards provided analyses. The concentration of Pb ranged from 11 to 420 ppm; Cr, 4.3 - 52 ppm; Cu, 6.5 - 390 ppm; Zn, 17 - 480 ppm; Cd, 0.4 - 12 ppm; and Sb, 2.9 - 20 ppm. High levels of all metals characterize the urban core area of El Paso, which dates to the late 19th Century. This area hosts both commercial and old residential structures, as well as major highways and a large railroad yard. There currently is, and was in the past, considerable light industry in the area. Two highly traveled highway and one railroad border crossing over the Rio Grande into contiguous Cd. Juarez (population close to 2 million) add to current and past contamination. A century-old Pb-Cu-Zn smelter, recently demolished, forms the western boundary of the urban core. Heavy metal pollution from the smelter is recognized near the former site. Its effect on the rest of the urban core is uncertain due to the current and former presence of other heavy metal sources. Aggressive post-World War II growth and expansion of El Paso into the surrounding desert, as is common in the US Southwest, placed newer housing onto more pristine land surfaces. This is reflected in generally low-to-background levels of heavy metals in these newer areas of the city. Thus there is a strong contamination and heavy metals exposure risk gradient between older and newer neighborhoods within a single city

  17. INTRA-URBAN GRADIENTS OF FINE PARTICULATE MATTER (PM2.5) IN THE EL PASO CHILDREN'S HEALTH STUDY

    EPA Science Inventory

    El Paso, Texas, a metropolitan area with over 500,000 residents, is located directly across the US/Mexico border from Ciudad Juarez with over 1 million residents. An estimated 18 million vehicles annually cross the international border between these two large cities. The border...

  18. SPRINGTIME SPATIAL CONCENTRATION GRADIENTS OF NITROGEN DIOXIDE AND VOLATILE ORGANIC SPECIES IN THE EL PASO CHILDREN'S HEALTH STUDY

    EPA Science Inventory

    Each year, over 18 million vehicles cross the international border between El Paso, TX (USA) and Ciudad Juarez (Mexico). The border traffic congestion, as well as the more typical intra-urban and interstate traffic, provide an opportunity to investigate the health effects of PM ...

  19. Attic dust analysis approach for evaluation of heavy metal deposition in the El Paso Del Norte Region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the 90 years from 1887 to 1977, a large smelter in the El Paso Del Norte region of North America smelted many ores including copper, lead, and zinc. In order to identify the patterns of heavy metal dispersion from the smelter, we sampled attic dust and dust from undisturbed surfaces in 15 bu...

  20. 75 FR 42737 - Texas Gas Service Company, a Division of ONEOK, Inc. v. El Paso Natural Gas Company; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ... Energy Regulatory Commission Texas Gas Service Company, a Division of ONEOK, Inc. v. El Paso Natural Gas Company; Notice of Complaint July 9, 2010. Take notice that on July 7, 2010, pursuant to section 5 of the Natural Gas Act, 15 U.S.C. 717d (2006) and Rule 206 of the Federal Energy Regulatory Commission's Rules...

  1. Karst development in the Tobosa basin (Ordovician-Devonian) strata in the El Paso border region of west Texas

    SciTech Connect

    Lemone, D.V. . Dept. of Geological Sciences)

    1993-02-01

    Karst development within the Tobosa basin strata in the El Paso border region is best displayed during two time intervals: Middle Ordovician (27 Ma) developed on the Lower Ordovician El Paso Group and Middle Silurian to Middle Devonian (40 Ma) karst developed on the Lower-Middle Fusselman Formation. These major exposure intervals are recognized in regional outcrops as well as in the subsurface of the Permian Basin where they form major reservoirs. Minor local karsting is noted also within and upon the Upper Ordovician (Montoya Group) and within the shoaling upward members of overlying the Fusselman Formation. Middle Ordovician karsting with major cavern development extends down into McKellingon Canyon Formation approximately 1,000 feet below the top of the Lower Ordovician El Paso Group. The McKellingon is overlain by the cavern roof-forming early diagenetic dolomites, lower Scenic Drive Formation which in turn is overlain by the locally karsted upper Scenic Drive and Florida Mountains formations. Collapse of the overlying Montoya Group into El Paso Group rocks is observed. The Fusselman Formation rests disconformably on the Montoya Group. It is a massive, vuggy, fine- to coarsely-crystalline, whitish dolomite. Extensive karsting has developed on the top of the Fusselman. The middle Devonian Canutillo Formation with a basal flooding deposit overlies this karst surface. Minor karsting following fracture systems extends from the major karst of the El Paso Group up into the major karst in the Fusselman. The karst seems to be following and developing along the same linear fracture systems. If so, it is not unreasonable to interpret these fracture systems as being inherited from the earlier Precambrian structures underlying them.

  2. Lead Contamination of Urban Soil in the El Paso (Texas)--Juarez (Mexico) Border Metroplex

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E.; Amaya, M. A.; Clague, J.

    2005-12-01

    We present an unusually detailed map of the distribution of lead in El Paso--Juarez soils, one that is based on x-ray fluorescence analysis of 1000 composite soil samples collected in the region. Mixing equal volumes of samples taken from the public space in front of individual houses or structures around a single municipal block created a single composite sample to characterize each of the 500 blocks studied in each city. Maps based on such composites highlight the distribution of lead at the neighborhood level, and de-emphasize any anomalous elevated level associated with an individual house or structure. In both cities, levels of lead are highest in their contiguous downtown commercial districts, which date to the 19th Century and are linked by the traditional border river crossing area at the Rio Grande. Rail yards, transport hubs, light industry complexes, and the oldest residential areas lie adjacent to, and inter-tongue with, this commercial district on both sides of the border. A century-old smelter, placed on standby six years ago, abuts the western limit of the old urban core in El Paso. The continuity of this elevated-lead zone, the proximity of the smelter, the many potential lead sources associated with traditional commercial activities, and the age of its structures, make it difficult to differentiate lead sources. Lead values decrease systematically away from this urban core zone, with the lowest levels generally encountered in peripheral, lightly populated developments and communities. The binational distribution of Pb in soil is consistent with Pb measurements reported on particulate matter taken from nine air monitoring stations (covering both cities) during the 1990s. Soil data thus can complement air studies by providing an essentially infinite geographic network of sampling sites that, with varying accuracy, record and integrate air conditions over years and decades. Research supported by NIEHS Grant 1RO1-ES11367.

  3. Unusual Recharge Processes near Arroyos of the Rio Grande Aquifer, El Paso/Juarez Area

    NASA Astrophysics Data System (ADS)

    Merino, M.; Hibbs, B. J.; Hogan, J.; Eastoe, C. J.; Druhan, J.

    2005-12-01

    The twin-cities of El Paso and Juarez share the water resources of the Hueco Bolson aquifer and overlying Rio Grande aquifer. Both aquifers span the international border between Mexico and the United States. Salinity in the Rio Grande aquifer varies widely, some parts of the shallow aquifer containing less than 1,000 mg/L total dissolved solids (TDS), other parts of the aquifer exceeding 5,000 mg/L TDS. One sizable part of the "Lower Valley" area, approximately 45 km below El Paso contains very dilute water near the outer edge of the floodplain. Historically it had been thought that the dilute waters in this location were derived from recharge from arroyos that drained proximal parts of the Hueco Bolson. Instead, our hydrogen and oxygen isotope data and carbon-14 data indicate that these dilute waters were derived from pre-dam infiltration of the Rio Grande. Relatively light and slightly evaporated pre-dam waters (-11.5 del O18) at the arroyos are also relatively young (60 to 90 percent modern carbon), tagging them as runoff waters from pre-dam snowmelt in Colorado. These isotopically light waters are found up to 110 meters beneath land surface. Prior to Rio Grande rectification and channelization of the mid-1930's, the Rio Grande flowed near the outer edge of the floodplain where these pre-dam, dilute waters are found at depth. Review of predevelopment drill stem tests indicated a permeable zone about 150 to 230 meters deep that had a lower hydraulic head than the overlying Rio Grande aquifer. The permeable zone acted as a predevelopment sink for flow that induced recharge from the Rio Grande and Rio Grande aquifer. Thus, we can account for local predevelopment recharge of the Rio Grande aquifer from infiltration of dilute water from the Rio Grande prior to the historic era of channel rectification, and not from recharge from flanking arroyos as had been postulated by previous researchers.

  4. Irregular recurrence of paleoearthquakes along the central Garlock fault near El Paso Peaks, California

    USGS Publications Warehouse

    Dawson, T.E.; McGill, S.F.; Rockwell, T.K.

    2003-01-01

    New investigations at the El Paso Peaks paleoseismic site have refined and extended the record of paleoearthquakes for the central Garlock fault. Event evidence, in the form of buried fissures, scarps, folds, and upward terminations, has allowed us to identify six well-resolved earthquakes, designated as events W, U, R, Q, K, and F, within the last ???7000 years. The exposures that we excavated did not reveal additional evidence for three poorly resolved events reported by McGill and Rockwell [1998]. Evidence for event Y, identified in the previous study, was reexamined and found not to be a paleoearthquake. Radiocarbon dates of detrital charcoal, combined with a method of interpolating the event ages with revised sedimentation rates, provide our preferred constraints on the timing of faulting events. The most recent surface-rupturing earthquake, event W, occurred between A.D. 1450 and 1640. The penultimate event U occurred between A.D. 675 and 950. Event R, which was unrecognized in the previous study, occurred between A.D. 250 and 475. Event Q occurred relatively shortly before event R, between A.D. 25 and 275. Event K occurred between 3340 and 2930 B.C. The oldest identified paleoearthquake, event F, occurred between 5300 and 4670 B.C. The event ages indicate that earthquake recurrence is highly irregular at the El Paso Peaks site, with individual preferred intervals ranging from as little as 215 years to as many as 3300 years. The irregular recurrence of surface-rupturing earthquakes along the central Garlock fault may be related to temporal and spatial clustering of earthquakes proposed for faults in the Eastern California Shear Zone.

  5. Aerosol characterizaton in El Paso-Juarez airshed using optical methods

    NASA Astrophysics Data System (ADS)

    Esparza, Angel Eduardo

    2011-12-01

    The assessment and characterization of atmospheric aerosols and their optical properties are of great significance for several applications such as air pollution studies, atmospheric visibility, remote sensing of the atmosphere, and impacts on climate change. Decades ago, the interest in atmospheric aerosols was primarily for visibility impairment problems; however, recently interest has intensified with efforts to quantify the optical properties of aerosols, especially because of the uncertainties surrounding the role of aerosols in climate change. The main objective of the optical characterization of aerosols is to understand their properties. These properties are determined by the aerosols' chemical composition, size, shape and concentration. The general purpose of this research was to contribute to a better characterization of the aerosols present in the Paso del Norte Basin. This study permits an alternative approach in the understanding of air pollution for this zone by analyzing the predominant components and their contributions to the local environment. This dissertation work had three primary objectives, in which all three are intertwined by the general purpose of the aerosol characterization in the Paso del Norte region. The first objective was to retrieve the columnar aerosol size distribution for two different cases (clean and polluted scenarios) at each season (spring, summer, fall and winter) of the year 2009. In this project, instruments placed in buildings within the University of Texas at El Paso (UTEP) as well as a monitoring site (CAMS 12) from the Texas Commission on Environmental Quality (TCEQ) provided the measurements that delimited the aerosol size distribution calculated by our model, the Environmental Physics Inverse Reconstruction (EPIRM) model. The purpose of this objective was to provide an alternate method of quantifying and size-allocating aerosols in situ, by using the optical properties of the aerosols and inversely reconstruct and

  6. Providing Bridges from 2YC to 4YC in the El Paso Region

    NASA Astrophysics Data System (ADS)

    Doser, D. I.; Villalobos, J. I.

    2012-12-01

    For the past ~3 years the University of Texas at El Paso (UTEP) has been working closely with El Paso Community College (EPCC) to help ease the transfer of geoscience and environmental science students between our institutions. We have initiated a number of activities to accomplish this including: articulation of degree programs to build a 2+2 transfer plan, review of introductory course content, cross-institution research projects with EPCC students and co-sponsored student research symposiums. One of the most successful activities has been our cross-institutional research projects that involve either individual students working with a UTEP undergraduate/UTEP faculty member team or EPCC classes that join UTEP classes for some aspect of field work or project. The EPCC students gain confidence in their ability to succeed by working with UTEP students and finding out that they are as capable of engaging in and completing research as their 4YC peers. They also have an opportunity to meet UTEP professors first as mentors and professional colleagues rather than in a classroom setting. The research symposium serves as an excellent venue for showcasing their research to the EPCC and UTEP community, as well as interacting with local and out of town professionals who serve as judges for the research presentations. Feedback provided by the judges assists students in refining their presentations for out of town professional meetings. The first students participating in the research program are graduating from UTEP in the summer and fall of 2012. Many EPCC students involved in research have obtained summer internships in industry, the public sector or at other academic institutions, some even prior to attending UTEP. Several have received competitive scholarships. The greatest challenges to the research program include finding UTEP faculty who are willing to work with EPCC students and financial support for the students during their research activities. The greatest challenges

  7. Infrasound from the El Paso super-bolide of October 9, 1997

    SciTech Connect

    ReVelle, D.O.; Whitaker, R.W.; Armstrong, W.T.

    1998-12-31

    During the noon hour on October 9, 1997 an extremely bright fireball ({approx}-21.5 in stellar magnitude putting it into the class of a super-bolide) was observed over western Texas with visual sightings from as far away as Arizona to northern Mexico and even in northern New Mexico over 300 miles away. This event produced tremendously loud sonic boom reports in the El Paso area. It was also detected locally by 4 seismometers which are part of a network of 5 seismic stations operated by the University of Texas at El Paso (UTEP). Subsequent investigations of the data from the six infrasound arrays used by LANL (Los Alamos National Laboratory) and operated for the DOE (Department of Energy) as a part of the CTB (Comprehensive Test Ban) Research and Development program for the IMS (International Monitoring System) showed the presence of an infrasonic signal from the proper direction at the correct time for this super-bolide from two of the six arrays. Both the seismic and infrasound recordings indicated that an explosion occurred in the atmosphere at source heights from 28--30 km, having its epicenter slightly to the northeast of Horizon City, Texas. The signal characteristics, analyzed from {approx}0.1 to 5.0 Hz, include a total duration of {approx}4 min (at Los Alamos, LA) to >{approx}5 min at Lajitas, Texas, TXAR, another CTB IMS array operated by E. Herrin at Southern Methodist University (SMU) for a source directed from LA toward {approx}171--180 deg and from TXAR of {approx}321-4 deg respectively from true north. The observed signal trace velocities (for the part of the recording with the highest cross-correlation) at LA ranged from 300--360 m/sec with a signal velocity of 0.30 {+-} 0.03 km/sec, implying a Stratospheric (S Type) ducted path. The dominant signal frequency at LA was from 0.20 to 0.80 Hz, with a peak near 0.3 Hz. These highly correlated signals at LA had a very large, peak to peak, maximum amplitude of 21.0 microbars (2.1 Pa). The analysis, using

  8. Confirmation and investigation of higher science curiosity in Juarez Middle School students compared to their peers in El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Carmona Miranda, Karla

    In the last 20 years attitudes towards science and science classes in K-12 education have been an important topic of investigation due to the decreasing number of students choosing Science, Technology, Engineering and Math (STEM) related careers, and the increasing need for STEM prepared workers to cover the job demands of the future. The purpose of this study is to confirm a previously measured difference in scientific curiosity between middle school students in El Paso and in Ciudad Juarez, and to collect additional data that might tell us what the possible factors or reasons for this difference are. Our sample consists of 156 middle school students from Juarez public schools, and 448 middle school students from El Paso public middle schools. The Children's Science Curiosity Scale of Harty & Beall (1984) will be used to measure the curiosity level. Additionally, the students will be asked to respond to "Why do you like or dislike science?" Our results show that those obtained by Ortiz (2006) in a similar study persist but with a reduction of standard deviations. The percentage of students that state that they do not like science in Ciudad Juarez and El Paso are 9% and 14%, respectively. The most common reason to like science among students in Ciudad Juarez was related to the topics covered in class, and among students in El Paso was related to the experiments and hands-on activities done in class. After analyzing contingency tables with chi-squared tests and calculating the respective contingency coefficients, it is safe to say that even though relationships between the reasons to like or dislike science and country exist, these relationships are not strong. Other results, limitations, and future research also are discussed.

  9. The 1996 and 1997 Paso del Norte ozone studies: An overview of the field studies and data analyses

    SciTech Connect

    MacDonald, C.P.; Roberts, P.T.; Main, H.H.; Dye, T.S.; Coe, D.L.; Yarbrough, J.

    1999-07-01

    This paper summarizes the measurement campaigns of the 1996 and 1997 Paso del Norte Ozone Studies, the resultant data sets, and the findings and conclusions that arose from subsequent data analyses. The purpose of these data analyses was to develop an understanding of the significant chemical and physical processes that lead to high concentrations of ozone in the Paso del Norte study region which includes El Paso, TX; Sunland Park, NM; and Juarez, Mexico. High ozone concentrations resulted from a combination of conditions, including slow convective boundary layer (CBL) growth, reduced CBL depth, light surface winds, and high concentrations of ozone precursor at ground level in the morning. Synoptic-scale meteorological conditions observed during high ozone episodes included an upstream aloft high-pressure system, and aloft warming. Aloft carryover of ozone and ozone precursors did not significantly contribute to the surface ozone concentration. Furthermore, hydrocarbon and NO{sub x} data, although spatially limited, showed that the system is more often NO{sub x}-limited rather than VOC-limited.

  10. Minority Universities Systems Engineering (MUSE) Program at the University of Texas at El Paso

    NASA Technical Reports Server (NTRS)

    Robbins, Mary Clare; Usevitch, Bryan; Starks, Scott A.

    1997-01-01

    In 1995, The University of Texas at El Paso (UTEP) responded to the suggestion of NASA Jet Propulsion Laboratory (NASA JPL) to form a consortium comprised of California State University at Los Angeles (CSULA), North Carolina Agricultural and Technical University (NCAT), and UTEP from which developed the Minority Universities Systems Engineering (MUSE) Program. The mission of this consortium is to develop a unique position for minority universities in providing the nation's future system architects and engineers as well as enhance JPL's system design capability. The goals of this collaboration include the development of a system engineering curriculum which includes hands-on project engineering and design experiences. UTEP is in a unique position to take full advantage of this program since UTEP has been named a Model Institution for Excellence (MIE) by the National Science Foundation. The purpose of MIE is to produce leaders in Science, Math, and Engineering. Furthermore, UTEP has also been selected as the site for two new centers including the Pan American Center for Earth and Environmental Sciences (PACES) directed by Dr. Scott Starks and the FAST Center for Structural Integrity of Aerospace Systems directed by Dr. Roberto Osegueda. The UTEP MUSE Program operates under the auspices of the PACES Center.

  11. The geologic structure of part of the southern Franklin Mountains, El Paso County, Texas

    SciTech Connect

    Smith, W.R.; Julian, F.E. . Dept. of Geosciences)

    1993-02-01

    The Franklin Mountains are a west tilted fault block mountain range which extends northwards from the city of El Paso, Texas. Geologic mapping in the southern portion of the Franklin Mountains has revealed many previously unrecognized structural complexities. Three large high-angle faults define the boundaries of map. Twenty lithologic units are present in the field area, including the southernmost Precambrian meta-sedimentary rocks in the Franklin Mountains (Lanoria Quartzite and Thunderbird group conglomerates). The area is dominated by Precambrian igneous rocks and lower Paleozoic carbonates, but Cenozoic ( ) intrusions are also recognized. Thin sections and rock slabs were used to describe and identify many of the lithologic units. The Franklin Mountains are often referred to as a simple fault block mountain range related to the Rio Grande Rift. Three critical regions within the study area show that these mountains contain structural complexities. In critical area one, Precambrian granites and rhyolites are structurally juxtaposed, and several faults bisecting the area affect the Precambrian/Paleozoic fault contact. Critical area two contains multiple NNW-trending faults, three sills and a possible landslide. This area also shows depositional features related to an island of Precambrian rock exposed during deposition of the lower Paleozoic rocks. Critical area three contains numerous small faults which generally trend NNE. They appear to be splays off of one of the major faults bounding the area. Cenozoic kaolinite sills and mafic intrusion have filled many of the fault zones.

  12. The DOE infrastructure support program at the University of Texas at El Paso. Final report

    SciTech Connect

    1998-11-01

    The University of Texas at El Paso (UTEP) is located on 300 acres, only a few hundred years from the US/Mexico border. The DOE Infrastructure Support Program was initiated at UTEP in 1987. The purpose of the program was to assist the University in building the infrastructure required for its emerging role as a regional center for energy-related research. Equally important was the need to strength the University`s ability to complete for sponsored energy-related programs at the state and national levels and to provide opportunities for faculty, staff and students to participate in energy-related research and outreach activities. The program had four major objectives, as follows: (1) implement energy research, outreach and demonstration projects already funded, and prepare new proposals to fund university research interests; (2) establish an Energy Center as a separate operational entity to provide continuing infrastructure support for energy-related programs; (3) strengthen university/private sector energy research linkages; and (4) involve minority graduate and undergraduate students in energy research and outreach activities. Each of the above objectives has been exceeded substantially, and, as a consequence, the University has become a regional leader in energy and environmental research and outreach efforts.

  13. Sensitivity Modeling Study for an Ozone Occurrence during the 1996 Paso Del Norte Ozone Campaign

    PubMed Central

    Lu, Duanjun; Reddy, Remata S.; Fitzgerald, Rosa; Stockwell, William R.; Williams, Quinton L.; Tchounwou, Paul B.

    2008-01-01

    Surface ozone pollution has been a persistent environmental problem in the US and Europe as well as the developing countries. A key prerequisite to find effective alternatives to meeting an ozone air quality standard is to understand the importance of local anthropogenic emissions, the significance of biogenic emissions, and the contribution of long-range transport. In this study, an air quality modeling system that includes chemistry and transport, CMAQ, an emission processing model, SMOKE, and a mesoscale numerical meteorological model, WRF, has been applied to investigate an ozone event occurring during the period of the 1996 Paso del Norte Ozone Campaign. The results show that the modeling system exhibits the capability to simulate this high ozone occurrence by providing a comparable temporal variation of surface ozone concentration at one station and to capture the spatial evolution of the event. Several sensitivity tests were also conducted to identify the contributions to high surface ozone concentration from eight VOC subspecies, biogenic VOCs, anthropogenic VOCs and long-range transportation of ozone and its precursors. It is found that the reductions of ETH, ISOP, PAR, OLE and FORM help to mitigate the surface ozone concentration, and like anthropogenic VOCs, biogenic VOC plays a nonnegligible role in ozone formation. But for this case, long-range transport of ozone and its precursors appears to produce an insignificant contribution. PMID:19190351

  14. Attic Dust Analysis Approach for Evaluation of Heavy Metal Deposition on the El Paso Del Norte Region

    NASA Astrophysics Data System (ADS)

    Shekhter, E. G.; van Pelt, S.; Pannell, K.; Gill, T. E.; Barnes, M. A.

    2010-12-01

    The El Paso del Norte region in the United States is a region of complex topography that is the home to more than 2 million people who share the same air. A large non-ferrous smelter (primary lead-copper smelter),owned by the American Smelting and Refining Company (ASARCO), was functioning in the Rio Grande River valley on the west side of the Franklin Mountains that divide the city of El Paso and across the river from Juarez, Mexico’s largest city on the United States border. During the more than 100 years of operation, beginning in 1887, the ASARCO smelter emissions considerably deteriorated the already complex environmental condition on the US-Mexican border. In order to identify the sources and patterns of heavy metal dispersion, we used an attic dust analyses approach which has not been previously been applied in this area. Undisturbed attic dust can provide an integrated history of atmospheric loading of particulates emanating from geological, biological and anthropogenic sources and can help to reconstruct the air pollution history on a local scale. We sampled attic dust and dust from undisturbed surfaces in 15 buildings of varying ages from three neighborhoods in the cities of El Paso and Juarez. The dust samples and samples of unpolluted buried soil horizons in the area were extracted with aqua regia and analyzed by ICP-AES and ICP-MS. Enrichment ratios (ER) were calculated by dividing the concentration of a trace metal in the attic dust by the mean concentration of the same element in the buried soil horizons. Mean ER for Pb were 263.3, 95.4, and 70.2 for dust collected in a neighborhood near the smelter, downtown Juarez, and an El Paso neighborhood on the other side of the Franklin Mountains from the smelter. Greater ER for As, Cd, Zn, Sb, and Cu followed the same trends, by neighborhood, noted for Pb. In addition, dust collected from attics surfaces (pipes, ducts, storage containers) post-dating smelter disclosure had lower ER for the trace metals

  15. Dispersion Modeling of Inert Particulate Matter in the El Paso, TX- Cd. Juarez, MX Region

    NASA Astrophysics Data System (ADS)

    Pearson, R.; Fitzgerald, R.

    2005-05-01

    The El Paso, TX-Cd. Juarez, MX region is subject to the emission of inert particulate matter (PM) into the atmosphere, from a variety of sources. The impact of these emissions has been studied extensively in for regulatory compliance in the area of health effects, air quality and visibility. Little work has been done to study the fate and transport of the particulate matter within the region. The Environmental Physics Group at The University of Texas at El Paso has recently applied the SARMAP Air Quality Model (SAQM) to model the dispersion of inert particulate matter in the region. The meteorological data for the SAQM was created with the Penn State/NCAR meteorological modeling system, version 5 (MM5). The SAQM was used to simulate three common occurrences for large particulate emission and concentration. The first was times of heavy traffic volume at the international bridges which cause large numbers of cars to sit, with engines running, for extended periods of time. The second was moderate to high wind events that cause large amounts of coarse particulate matter to become entrained in the atmosphere and transported into and around the region. The third is a temperature inversion which traps the particulate matter at the surface during morning rush hour. The initial conditions for particulate matter, for the two cases involving mobile emissions, were derived from the 1999 version 3 national emissions inventory (NEI) mobile, on-road data from the EPA. Output from the MM5 was used to as the meteorological driver for the SAQM. The MM5 was initialized with data from the NCAR reanalysis project. Meteorological data collected in the region bye the Texas Commission on Environmental Quality (TCEQ) and the EPA was used for Four Dimensional Data Assimilation. The MM5 was nudged with gridded, surface and observational data. Statistical analysis was done on the MM5 for the variables, wind speed, wind direction, temperature and mixing ratio. The statistics performed included

  16. Solute Sources and Budget for the Rio Grande above El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Hogan, J. F.; Phillips, F. M.; Hendrickx, J. M.

    2001-12-01

    Issues of water quality, especially salinity, limit the use of water resources from the Rio Grande. Identification and quantification of salinity sources is critical for improved river management. In the headwater region salts are typically derived from atmospheric deposition and chemical weathering reactions. Salinity increases during transit may result from both natural (saline groundwater, hydrothermal springs and dissolution of evaporite deposits) and anthropogenic (agricultural return flow and wastewater from sewage treatment plants) sources. These increases are magnified by evapotranspiration (this includes evaporation from open water, transpiration from irrigated agriculture and transpiration from natural riparian areas). With multiple salinity sources and evapotranspiration acting simultaneously, understanding the solute balance for the Rio Grande at a level needed for improved river management is difficult. We have conducted synoptic sampling of the Rio Grande from the headwaters in Colorado to south of El Paso, Texas. Sampling was conducted in January and August of 2000 and 2001. The total dissolved solids content (TDS) of the Rio Grande increases from < 50 mg/L in headwater regions of Colorado to > 2000 mg/L south of El Paso, Texas. The Cl/Br (wt/wt) ratio for river water increases from ~50 in the headwaters (typical for atmospheric deposition) to ~700 in the lower basin. This increase in Cl/Br ratio demonstrates the importance of additional salinity sources. Three end-members are recognized using Cl/Br mixing plots for winter samples: atmospheric deposition, a hydrothermal end-member localized around Truth of Consequences, NM, and a third end-member that may represent groundwater. Samples collected during the summer months are shifted off the winter mixing lines indicating concentration through ET. Increases in salinity were not a simple function of distance downriver, but rather occurred in a series of steps. Some of these steps are correlated with

  17. Influence of deposit architecture on intrastratal deformation, slope deposits of the Tres Pasos Formation, Chile

    NASA Astrophysics Data System (ADS)

    Auchter, Neal C.; Romans, Brian W.; Hubbard, Stephen M.

    2016-07-01

    Slope sediments on passive and active margins deform and fail across a broad range of scales ranging from loading and sediment remobilization near the sediment-water interface to submarine landslides and mass movements that incorporate significant volumes of slope deposits. Deformational styles are characterized by updip extension and downdip compressional features that occur above a detachment surface. Conditions for failure and deformation include the presence of weak layer(s) that serve as a detachment surface, competency contrasts that allow for detachment and downslope movement, deformation above a detachment surface, and a triggering mechanism(s) that initiates failure. Slope failure processes and products are well documented at scales resolvable by seismic-reflection surveys and in instances of extensive downslope failure, but the processes and products associated with intermediate-scale slope deformation are poorly understood. Intrastratal deformation is defined as stratigraphically isolated zones of deformation bounded above and below by concordant and undeformed strata. In this study, outcrop examples of intrastratal deformation from the Upper Cretaceous Tres Pasos Formation are used to elucidate the influence of depositional architecture on slope deformation. The facies distribution associated with compensational stacking of lobe deposits is shown to have a first-order control on the location and style of deformation. Detachment planes that form in mudstone deposits associated with lobe fringe and interlobe deposits are spatially limited and deformation is restricted to interbedded sandstone and mudstone associated with off-axial lobe positions. Downslope translation was arrested by stratigraphic buttresses associated with more sandstone-prone axial deposits. Emplacement of a regionally extensive mass transport deposit is interpreted as the triggering mechanism for contemporaneous intrastratal deformation of > 60 m of underlying stratigraphy. A vertical

  18. Modeling particle number concentrations along Interstate 10 in El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Olvera, Hector A.; Jimenez, Omar; Provencio-Vasquez, Elias

    2014-12-01

    Annual average daily particle number concentrations around a highway were estimated with an atmospheric dispersion model and a land use regression model. The dispersion model was used to estimate particle concentrations along Interstate 10 at 98 locations within El Paso, Texas. This model employed annual averaged wind speed and annual average daily traffic counts as inputs. A land use regression model with vehicle kilometers traveled as the predictor variable was used to estimate local background concentrations away from the highway to adjust the near-highway concentration estimates. Estimated particle number concentrations ranged between 9.8 × 103 particles/cc and 1.3 × 105 particles/cc, and averaged 2.5 × 104 particles/cc (SE 421.0). Estimates were compared against values measured at seven sites located along I10 throughout the region. The average fractional error was 6% and ranged between -1% and -13% across sites. The largest bias of -13% was observed at a semi-rural site where traffic was lowest. The average bias amongst urban sites was 5%. The accuracy of the estimates depended primarily on the emission factor and the adjustment to local background conditions. An emission factor of 1.63 × 1014 particles/veh-km was based on a value proposed in the literature and adjusted with local measurements. The integration of the two modeling techniques ensured that the particle number concentrations estimates captured the impact of traffic along both the highway and arterial roadways. The performance and economical aspects of the two modeling techniques used in this study shows that producing particle concentration surfaces along major roadways would be feasible in urban regions where traffic and meteorological data are readily available.

  19. Modeling particle number concentrations along Interstate 10 in El Paso, Texas

    PubMed Central

    Olvera, Hector A.; Jimenez, Omar; Provencio-Vasquez, Elias

    2014-01-01

    Annual average daily particle number concentrations around a highway were estimated with an atmospheric dispersion model and a land use regression model. The dispersion model was used to estimate particle concentrations along Interstate 10 at 98 locations within El Paso, Texas. This model employed annual averaged wind speed and annual average daily traffic counts as inputs. A land use regression model with vehicle kilometers traveled as the predictor variable was used to estimate local background concentrations away from the highway to adjust the near-highway concentration estimates. Estimated particle number concentrations ranged between 9.8 × 103 particles/cc and 1.3 × 105 particles/cc, and averaged 2.5 × 104 particles/cc (SE 421.0). Estimates were compared against values measured at seven sites located along I10 throughout the region. The average fractional error was 6% and ranged between -1% and -13% across sites. The largest bias of -13% was observed at a semi-rural site where traffic was lowest. The average bias amongst urban sites was 5%. The accuracy of the estimates depended primarily on the emission factor and the adjustment to local background conditions. An emission factor of 1.63 × 1014 particles/veh-km was based on a value proposed in the literature and adjusted with local measurements. The integration of the two modeling techniques ensured that the particle number concentrations estimates captured the impact of traffic along both the highway and arterial roadways. The performance and economical aspects of the two modeling techniques used in this study shows that producing particle concentration surfaces along major roadways would be feasible in urban regions where traffic and meteorological data are readily available. PMID:25313294

  20. Evidence for long-term impact of Pasos Adelante: using a community-wide survey to evaluate chronic disease risk modification in prior program participants.

    PubMed

    Carvajal, Scott C; Miesfeld, Noelle; Chang, Jean; Reinschmidt, Kerstin M; de Zapien, Jill Guernsey; Fernandez, Maria L; Rosales, Cecilia; Staten, Lisa K

    2013-10-01

    Effective community-level chronic disease prevention is critical to population health within developed and developing nations. Pasos Adelante is a preventive intervention that aims to reduce chronic disease risk with evidence of effectiveness in US-Mexico residing, Mexican origin, participants. This intervention and related ones also implemented with community health workers have been shown to improve clinical, behavioral and quality of life indicators; though most evidence is from shorter-term evaluations and/or lack comparison groups. The current study examines the impact of this program using secondary data collected in the community 3-6 years after all participants completed the program. A proportional household survey (N = 708) was used that included 48 respondents who indicated they had participated in Pasos. Using propensity score matching to account for differences in program participants versus other community residents (the program targeted those with diabetes and associated risk factors), 148 natural controls were identified for 37 matched Pasos participants. Testing a range of behavioral and clinical indicators of chronic disease risk, logistic regression models accounting for selection bias showed two significant findings; Pasos participants were more physically active and drank less whole milk. These findings add to the evidence of the effectiveness of Pasos Adalente and related interventions in reducing chronic disease risk in Mexican-origin populations, and illustrate the use of innovative techniques for using secondary, community-level data to complement prior evaluation research.

  1. Identifying and locating tectonic tremor beneath the San Andreas Fault near Parkfield, CA, with the PASO array

    NASA Astrophysics Data System (ADS)

    Peterson, D. E.; Thurber, C. H.; Montgomery-Brown, E. D.; Brown, J. R.; Shelly, D. R.

    2011-12-01

    Tectonic tremor is a weak but persistent shaking of the Earth that was first discovered in subduction zones and later found beneath the San Andreas Fault (SAF). Tremor events represent spasmodic slip on the deep extension of the SAF, occurring at a depth of about 20-25 kilometers. Tremor occurs deeper than the nearby regular earthquakes, which can be found at maximum depths of 12-15 kilometers. Tremor is characterized by bursts of low frequency and/or very low frequency earthquakes (LFE/VLF) with dominant energy in the 1-10 Hz range. Tremor tells us about fault slip at depth in both space and time by illuminating the fault down to about the base of the crust. In the pursuit of deriving information about deep fault behavior and crustal structure, we are analyzing continuous data from the previously untapped Parkfield Area Seismic Observatory (PASO) temporary array, operated in 2000-2002 and 2004-2006. We started the identification process by correlating templates of known events from a nearby station array based on an existing catalog of tremor events. Using the dense PASO array and various correlation methods, including autocorrelation (Brown et. al. 2008), a scanning algorithm (Rowe, 2005), and cross correlation of template events (Shelly et al., 2007), we will refine the locations of these known events and seek to identify undiscovered clusters of LFEs and tremor. After generating an updated catalog initially for the month of September 2002, we will use S-wave arrivals from the 59 stations comprising the PASO array to provide strong constraints on the locations of identified events.

  2. Public health surveillance using emergency medical service logs - U.S.--Mexico land border, El Paso, Texas, 2009.

    PubMed

    2010-06-01

    In 2008, approximately 358 million travelers entered the United States, of whom 206 million arrived via land ports of entry (POEs) on the U.S.--Mexico border. Effective response to infectious diseases of public health importance among travelers requires timely identification and reporting to state and federal health authorities. Currently, notifications are made primarily by U.S. Customs and Border Protection (CBP) officers to CDC quarantine stations. However, CBP personnel have competing priorities and limited public health training.To evaluate the utility of monitoring emergency medical service (EMS) dispatch and response logs for ill travelers with symptoms or signs suggestive of infectious diseases, CDC screened medical records of patients transported by EMS during 2009 from the four POEs in El Paso, Texas. The screening was conducted using commercial software that monitors EMS logs and sends alerts in real time based on preestablished criteria (i.e., records containing keywords suggesting infectious diseases). Records that met the criteria were forwarded to El Paso Quarantine Station personnel and reviewed within 24 hours. If a reportable infectious disease was suspected, the final diagnosis was requested from the receiving hospital.This report summarizes the results of the evaluation, which found that, of 50,779 EMS responses in the city of El Paso, 455 (0.9%) records met alert criteria, 86 (0.2%) needed diagnostic confirmation, and nine (<0.1%) were for reportable infectious diseases. Monitoring EMS logs can enhance detection of travelers with serious infections at POEs but requires additional screening and follow-up by CDC.

  3. Utilizing geophysical methods for asessment and characterization of canal seepage in El Paso's lower valley irrigation delivery systems

    NASA Astrophysics Data System (ADS)

    Cegon, Amanda Brooke

    El Paso County Water Improvement District No. 1 (EPCWID No.1) delivers the Rio Grande water for agricultural production and urban uses through numerous networked irrigation canals. Of the nearly 86 billion gallons of water released annually for irrigation uses in Texas, billions are lost due to evaporation and seepage in unlined canals with 56 million gallons of the billions are lost in Franklin Canal annually due to improper lining and sediment variation of the canals. To characterize seepage patterns and identify areas of high seepage, Electrical Resistivity, Ground Truthing via soil sample analysis were used along three, half-mile long sectioned canals during irrigation and non-irrigation seasons. The data lines acquired were processed in EARTHIMAGER 2D to create 2D vertical resistivity inversion profiles to locate potential areas of high seepage/high resistivity. The research results will help El Paso County Water Improvement District No. 1 to develop management strategies to conserve water and improve the delivery efficiency systems which leads to economic growth in the Rio Grande Basin.

  4. The effect of urban canopy parameterizations on mesoscale meteorological model simulations in the Paso del Norte area

    SciTech Connect

    Brown, M.J.; Williams, M.D.

    1997-04-01

    Since mesoscale numerical models do not have the spatial resolution to directly simulate the fluid dynamics and thermodynamics in and around urban structures, urban canopy parameterizations are sometimes used to approximate the drag, heating, and enhanced turbulent kinetic energy (tke) produced by the sub-grid scale urban elements. In this paper, we investigate the effect of the urban canopy parameterizations used in the HOTMAC mesoscale meteorological model by turning the parameterizations on and off. The model simulations were performed in the Paso del Norte region, which includes the cities of El Paso and Ciudad Juarez, the Franklin and Sierra Juarez mountains, and the Rio Grande. The metropolitan area is surrounded by relatively barren scrubland and is intersected by strips of vegetation along the Rio Grande. Results indicate that the urban canopy parameterizations do affect the mesoscale flow field, reducing the magnitude of wind speed and changing the magnitude of the sensible heat flux and tke in the metropolitan area. A nighttime heat island and a daytime cool island exist when urban canopy parameters are turned on, but associated recirculation flows are not readily apparent. Model-computed solar, net, and longwave radiation values look reasonable, agreeing for the most part with published measurements.

  5. El Paso Electric Company Diablo Substation to the US-Mexico border 115kV transmission line project. Final Environmental Assessment

    SciTech Connect

    Not Available

    1992-04-01

    This Environmental Assessment documents the analysis of alternative corridors for development and operation of a proposed 115 kilovolt transmission line using private lands and transporting power to the US-Mexico international border. The project will require (1) an amendment to El Paso Electric Company`s existing export authorization to transfer power across this border, and (2) a Presidential Permit for construction of the transmission line. The project would be located in Dona Ana county in southern New Mexico, approximately five miles west of El Paso, Texas. The alternative corridors, specific locations within those corridors, and structure types are identified and analyzed in the environmental studies.

  6. Hydrogeological characterization of a bank filtration experiment site at the Rio Grande, El Paso, Texas, USA

    NASA Astrophysics Data System (ADS)

    Langford, R.; Schulze-Makuch, D.; Pillai, S.; Abdel-Fattah, A.; Widmer, K.

    2003-04-01

    An experiment site was constructed along an artificial channel of the Rio Grande in El Paso, Texas. The experiment was funded by the EPA and is designed to measure the effectiveness of bank filtration in an arid environment. Regionally, the experiment is important because of the hundreds of thousands of people drinking water from shallow wells drilled in close proximity to septic systems. A pumping well was drilled 17 meters from the stream bank and screened from 3.5 to 8 m depth. A cruciform array of observation wells with several multilevel completions allows detection of downstream and vertical movement of water as well as flow from the stream to the well. All of the wells were continuously cored during drilling. Analysis of the cores reveals that the site consists of two stacked channels filled with sand deposited from the meandering Rio Grande. A grid of ground-penetrating radar lines provided three-dimensional coverage between wells and showed bedding to 6.5 m depth. Constant head hydraulic conductivities show that the aquifer consists of two more permeable units separated by the less permeable upper fill of the lower channel complex, with vertical hydraulic conductivities of (1x10-6 to 2x10-6 m/s?). The intervals above and below this interval have the highest vertical conductivities (up to 3.5x10-5 m/s). A multiple pumping and tracer test was conducted using the cruciform array of the field site that consisted of a pumping well, 16 observation wells, and a stream sampling point. The average hydraulic conductivity of the geological media at the field site was about 2 x 10-3 m/s based on pumping test analysis. However, the type curve responses revealed significant heterogeneity of hydraulic conductivity throughout the field site. For the tracer test, bromide and microspheres were used as tracers. Microspheres were used to mimic the behavior of Giardia and Cryptosporidium. The tracers (bromide and microspheres of different sizes and colors) were injected in one

  7. Simulated ground-water flow in the Hueco Bolson, an alluvial-basin aquifer system near El Paso, Texas

    USGS Publications Warehouse

    Heywood, Charles E.; Yager, Richard M.

    2003-01-01

    The neighboring cities of El Paso, Texas, and Ciudad Juarez, Chihuahua, Mexico, have historically relied on ground-water withdrawals from the Hueco Bolson, an alluvial-aquifer system, to supply water to their growing populations. By 1996, ground-water drawdown exceeded 60 meters in some areas under Ciudad Juarez and El Paso. A simulation of steady-state and transient ground-water flow in the Hueco Bolson in westernmost Texas, south-central New Mexico, and northern Chihuahua, Mexico, was developed using MODFLOW-96. The model is needed by El Paso Water Utilities to evaluate strategies for obtaining the most beneficial use of the Hueco Bolson aquifer system. The transient simulation represents a period of 100 years beginning in 1903 and ending in 2002. The period 1903 through 1968 was represented with 66 annual stress periods, and the period 1969 through 2002 was represented with 408 monthly stress periods. The ground-water flow model was calibrated using MODFLOWP and UCODE. Parameter values representing aquifer properties and boundary conditions were adjusted through nonlinear regression in a transient-state simulation with 96 annual time steps to produce a model that approximated (1) 4,352 water levels measured in 292 wells from 1912 to 1995, (2) three seepage-loss rates from a reach of the Rio Grande during periods from 1979 to 1981, (3) three seepage-loss rates from a reach of the Franklin Canal during periods from 1990 to 1992, and (4) 24 seepage rates into irrigation drains from 1961 to 1983. Once a calibrated model was obtained with MODFLOWP and UCODE, the optimal parameter set was used to create an equivalent MODFLOW-96 simulation with monthly temporal discretization to improve computations of seepage from the Rio Grande and to define the flow field for a chloride-transport simulation. Model boundary conditions were modified at appropriate times during the simulation to represent changes in well pumpage, drainage of agricultural fields, and channel

  8. Nutrition Knowledge Predicts Eating Behavior of All Food Groups "except" Fruits and Vegetables among Adults in the Paso del Norte Region: Que Sabrosa Vida

    ERIC Educational Resources Information Center

    Sharma, Shreela V.; Gernand, Alison D.; Day, R. Sue

    2008-01-01

    Objective: To examine the association between nutrition knowledge and eating behavior in a predominantly Mexican American population on the Texas-Mexico border. Design: Cross-sectional using data from the baseline survey of the Que Sabrosa Vida community nutrition initiative. Setting: El Paso and surrounding counties in Texas. Participants: Data…

  9. ADVERSE IMPACT OF HOME DAMPNESS AND LENGTH OF RESIDENCE ON ATOPY AND LUNG FUNCTION AMONG CHILDREN IN EL PASO, TEXAS, USA

    EPA Science Inventory

    The El Paso Children's Health Study examined ambient exposures to motor vehicle emissions and their effect on the prevalence of allergy and asthma among children living in a major United States-Mexico border city. In the spring of 2001, the parents of all fourth and fifth grad...

  10. Seepage investigation on the Rio Grande from below Caballo Reservoir, New Mexico, to El Paso, Texas, 2012

    USGS Publications Warehouse

    Gunn, Mark A.; Roark, D. Michael

    2014-01-01

    A seepage investigation was conducted by the U.S. Geological Survey, in cooperation with the New Mexico Interstate Stream Commission, along an approximately 106-mile reach of the Rio Grande from below Caballo Reservoir, New Mexico, to El Paso, Texas, during June 26–28, 2012, to determine gain or loss of streamflow due to seepage to or from the river channel. Discharge measurements were made during the irrigation season at high flow including 5 sites along the Rio Grande, 5 diversions, and 63 inflows. The net gain or loss of flow in the river channel was computed for four reaches within the 106-mile reach of the Rio Grande. The normalized percentage difference was computed for each reach to determine the difference between discharge measured at upstream and downstream sites, and the normalized percentage uncertainty was computed to determine if a computed gain or loss exceeded cumulative uncertainty associated with measurement of discharge.

  11. Organic petrology of Paleocene Marcelina Formation coals, Paso Diablo mine, western Venezuela: Tectonic controls on coal type

    USGS Publications Warehouse

    Hackley, P.C.; Martinez, M.

    2007-01-01

    About 7??Mt of high volatile bituminous coal are produced annually from the four coal zones of the Upper Paleocene Marcelina Formation at the Paso Diablo open-pit mine of western Venezuela. As part of an ongoing coal quality study, we have characterized twenty-two coal channel samples from the mine using organic petrology techniques. Samples also were analyzed for proximate-ultimate parameters, forms of sulfur, free swelling index, ash fusion temperatures, and calorific value. Six of the samples represent incremental benches across the 12-13??m thick No. 4 bed, the stratigraphically lowest mined coal, which is also mined at the 10??km distant Mina Norte open-pit. Organic content of the No. 4 bed indicates an upward increase of woody vegetation and/or greater preservation of organic material throughout the life of the original mire(s). An upward increase in telovitrinite and corresponding decrease in detrovitrinite and inertinite illustrate this trend. In contrast, stratigraphically higher coal groups generally exhibit a 'dulling upward' trend. The generally high inertinite content, and low ash yield and sulfur content, suggest that the Paso Diablo coals were deposited in rain-fed raised mires, protected from clastic input and subjected to frequent oxidation and/or moisture stress. However, the two thinnest coal beds (both 0.7??m thick) are each characterized by lower inertinite and higher telovitrinite content relative to the rest of Paso Diablo coal beds, indicative of less well-established raised mire environments prior to drowning. Foreland basin Paleocene coals of western Venezuela, including the Paso Diablo deposit and time-correlative coal deposits of the Ta??chira and Me??rida Andes, are characterized by high inertinite and consistently lower ash and sulfur relative to Eocene and younger coals of the area. We interpret these age-delimited coal quality characteristics to be due to water availability as a function of the tectonic control of subsidence rate. It

  12. Aryl hydrocarbon receptor-mediated activity of particulate organic matter from the Paso del Norte airshed along the U.S.-Mexico border.

    PubMed Central

    Arrieta, Daniel E; Ontiveros, Cynthia C; Li, Wen-Whai; Garcia, Jose H; Denison, Michael S; McDonald, Jacob D; Burchiel, Scott W; Washburn, Barbara Shayne

    2003-01-01

    In this study, we determined the biologic activity of dichloromethane-extracted particulate matter < 10 micro m in aerodynamic diameter (PM10) obtained from filters at three sites in the Paso del Norte airshed, which includes El Paso, Texas, USA; Juarez, Chihuahua, Mexico, and Sunland Park, New Mexico, USA. The extracts were rich in polycyclic aromatic hydrocarbons (PAHs) and had significant biologic activity, measured using two in vitro assay systems: ethoxyresorufin-(O-deethylase (EROD) induction and the aryl hydrocarbon-receptor luciferase reporter system. In most cases, both EROD (5.25 pmol/min/mg protein) and luciferase activities (994 relative light units/mg) were highest in extracts from the Advance site located in an industrial neighborhood in Juarez. These values represented 58% and 55%, respectively, of induction associated with 1 micro M ss-naphthoflavone exposures. In contrast, little activity was observed at the Northeast Clinic site in El Paso, the reference site. In most cases, luciferase and EROD activity from extracts collected from the Tillman Health Center site, situated in downtown El Paso, fell between those observed at the other two sites. Overall, a statistically significant correlation existed between PM10 and EROD and luciferase activities. Chemical analysis of extracts collected from the Advance site demonstrated that concentrations of most PAHs were higher than those reported in most other metropolitan areas in the United States. Calculations made with these data suggest a cancer risk of 5-12 cases per 100,000 people. This risk estimate, as well as comparisons with the work of other investigators, raises concern regarding the potential for adverse health effects to the residents of this airshed. Further work is needed to understand the sources, exposure, and effects of PM10 and particulate organic material in the Paso del Norte airshed. PMID:12896850

  13. Implementation of InTeGrate Modules into Introductory Courses in the El Paso Higher Education Community

    NASA Astrophysics Data System (ADS)

    Doser, D. I.; Villalobos, J. I.; Henry, I. E.

    2014-12-01

    InTeGrate (Interdisciplinary Teaching about Earth for a Sustainable Future) has developed teaching modules that focus on Earth sustainability and Earth-centered societal issues. We have begun to implement modules on climate change, earth materials and freshwater into introductory geology and environmental science courses taught at the University of Texas at El Paso (UTEP), El Paso Community College (EPCC) and local early college high schools (ECHS) for classes of 20 to 220 students. Our eventual goal is to insure students taking introductory classes at any institution will be exposed to comparable content and be similarly prepared for advanced courses. Our initial results suggest that the modules' use of case studies and analysis of authentic data sets are very appealing to our student body (over 70% Hispanic). Since many students do not speak English at home, they were challenged by vocabulary presented in some modules. Modules containing glossaries and extensive background material (such as concept maps and annotated figures) proved very helpful to these students. The use of pre-activity quizzes insured that the students had mastered basic concepts needed for in-class activities. Modifications required to teach these modules in larger classes included condensing materials and reducing the amount of color figures to save paper and printer costs, streamlining dissemination/collection of in-class group assignments, and adapting assignments such as jigsaws and gallery walks to the confines of a large lecture hall with fixed seating. Student reflections indicated students were able to make connections to societal issues and retain these ideas through the end of the courses.

  14. Palynofacial analysis in alkaline soils and paleoenvironmental implications: The Paso Otero 5 archaeological site (Necochea district, Buenos Aires province, Argentina)

    NASA Astrophysics Data System (ADS)

    Grill, S.; Borromei, A.; Martínez, G.; Gutierrez, M. A.; Cornou, M. E.; Olivera, D.

    2007-06-01

    The combination of palynofacial and sedimentological analyses constitutes a valuable method for paleoenvironmental and paleoclimatic reconstructions, especially when fossil pollen information is scarce or absent. This methodology elucidates a late Pleistocene/Holocene sequence at the Paso Otero 5 archaeological site in the middle basin of the Quequén Grande River, Necochea district, Buenos Aires province, Argentina. Although the main factor responsible for the destruction of pollen grains is pH, biochemical and chemical oxidation and mechanical damage contribute to the deterioration as well. The site sequence indicates that extremely arid climatic conditions without vegetation cover prevailed during the late Pleistocene (˜12,000 14C yr BP), after which the climate changed to semiarid conditions associated with a disturbed environment due to strong eolian activity (Palynofacies 1 and 2; pre-10,400 14C yr BP). During the Pleistocene/Holocene transition (Palynofacies 3 and 4; ˜10,400-9400 14C yr BP), loamy facies associated with paleosoils reflected stable conditions and temporary ponds (spring deposits). Similar conditions occurred near the end of early Holocene (Palynofacies 5-9; ˜9400-6600 14C yr BP), whereas sandy and silty facies are associated with the flood margins of streams or rivers in the middle and late Holocene (Palynofacies 10-14; 6600-2500 14C yr BP). The top of the sequence (Palynofacies 15 and 16) consists of alluvium sediments and reflects locally humid conditions and modern vegetation with anthropic influence. One of the earliest Pampean sites with evidence of humans (10,450-10,200 14C yr BP), Paso Otero 5, provides a variety of megafauna bone specimens associated with ``fish-tail" projectile points, a lithic artifact diagnostic of early human occupations in South America. The site contains a complete stratigraphic record from the late Pleistocene to the present. The evidence presented herein supports the hypothesis that human colonization, at

  15. Soil-borne polycyclic aromatic hydrocarbons in El Paso, Texas: Analysis of a potential problem in the United States/Mexico border region

    PubMed Central

    De La Torre-Roche, Roberto J.; Lee, Wen-Yee; Campos-Díaz, Sandra I.

    2009-01-01

    Ultrasonic extraction followed by Stir Bar Sorptive Extraction (SBSE) and thermal desorption inline coupled with Gas Chromatography and Mass Spectrometry (TD/GC/MS)was used to perform a comprehensive determination of soil-borne polycyclic aromatic hydrocarbons (PAHs) in El Paso, Texas. The method provided good sensitivity and faster processing time for the analysis. The total PAHs in El Paso soil ranged from 0.1 to 2225.5 µg kg−1. Although the majority of PAH concentrations did not exceed the soil screening levels regulated by the United States Environmental Protection Agency, the existence of PAHs in this ecosystem is ubiquitous. Naphthalene were found in 100% of the soil samples; while the heavy PAHs (five- and six-ring) were not often detected and mostly remained in closer proximity to industrial areas and major traffic points. The results ruled out the possibility of petroleum refining as the significant source of local soil-borne PAH contamination, but they suggested that the PAHs found in El Paso soil were closely linked to human activities and possible other industrial processes. PMID:18768257

  16. A Smoke-Free Paso del Norte: Impact Over 10 Years on Smoking Prevalence Using the Behavioral Risk Factor Surveillance System

    PubMed Central

    Taylor, Thom; Hernandez, Nora; Kelly, Michael; Law, Jon; Colwell, Brian

    2012-01-01

    Objectives. We assessed the impact of a tobacco control initiative over 10 years on cessation and prevention. Methods. We examined 2000–2009 Behavioral Risk Factor Surveillance System cases of a metropolitan statistical area (MSA) with systematic tobacco control efforts throughout the decade (El Paso, TX) and 2 comparison MSAs similar in size and population with less coordinated tobacco control efforts (Austin-Round Rock, TX and San Antonio, TX). Results. Yearly, El Paso exhibited a 6% increase in the prevalence of former smokers, a 6% decrease in prevalence of daily smokers, and a 7% decrease in the prevalence of established smoking (≥ 100 cigarettes per lifetime and currently smoking); we did not observe similar trends in the comparison MSAs. There was no change in the prevalence of nondaily smokers in any of the MSAs. Conclusions. The coordinated tobacco control activities in El Paso are related to cessation among daily smokers and prevention of established smoking at the population level but have not stimulated cessation among nondaily smokers. Comprehensive tobacco control should focus more on not only daily smokers but also nondaily smokers. PMID:22494000

  17. Insurance Status Is a Greater Barrier Than Income or Acculturation to Chronic Disease Screening in the Mexican Origin Population in El Paso, Texas.

    PubMed

    Salinas, Jennifer J; de Heer, Hendrik D; Lapeyrouse, Lisa M; Heyman, Josiah M; Balcázar, Hector Guillermo

    2015-01-01

    The purpose of this study was to determine the association between income, insurance status, acculturation, and preventive screening for diabetes, high blood pressure, and cholesterol in Mexican American adults living in El Paso, Texas. This is a secondary data analysis using data from El Paso, Texas, that was collected between November 2007 and May 2009. Bivariate and stepwise regression analysis was used to determine the relationships between income, insurance, and acculturation factors on preventive screenings. Findings indicate that insurance status was associated with blood pressure check, blood sugar check, cholesterol screening, and any preventive screening. The association for income $40,000 + was explained by insurance. The only significant acculturation variable was language use for cholesterol. Disparities in preventive health screening in Mexican Americans were associated with primary insurance coverage in El Paso, Texas. With the border region being among the most medically underserved and underinsured areas in the United States, the results from this study suggest policy efforts are essential to ensure equal access to resources to maintain good health. Intervention efforts may include increasing awareness of enrollment information for insurance programs through the Affordable Care Act.

  18. Organic geochemical investigation and coal-bed methane characteristics of the Guasare coals (Paso Diablo mine, western Venezuela)

    USGS Publications Warehouse

    Quintero, K.; Martinez, M.; Hackley, P.; Marquez, G.; Garban, G.; Esteves, I.; Escobar, M.

    2011-01-01

    The aim of this work was to carry out a geochemical study of channel samples collected from six coal beds in the Marcelina Formation (Zulia State, western Venezuela) and to determine experimentally the gas content of the coals from the Paso Diablo mine. Organic geochemical analyses by gas chromatography-mass spectrometry and isotopic analyses on-line in coalbed gas samples were performed. The results suggest that the Guasare coals were deposited in a continental environment under highly dysoxic and low salinity conditions. The non-detection of 18??(H)-oleanane does not preclude that the organic facies that gave rise to the coals were dominated by angiosperms. In addition, the presence of the sesquiterpenoid cadalene may indicate the subordinate contribution of gymnosperms (conifers) in the Paleocene Guasare mire. The average coalbed gas content obtained was 0.6 cm3/g. ??13C and D values indicate that thermogenic gas is prevalent in the studied coals. Copyright ?? Taylor & Francis Group, LLC.

  19. Applications of particle-tracking techniques to bank infiltration: a case study from El Paso, Texas, USA

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, Ahmad; Langford, Richard; Schulze-Makuch, Dirk

    2008-08-01

    This paper presents results of a small scale study that utilized particle-tracking techniques to evaluate transport of river water through an alluvial aquifer in a bank infiltration testing site in El Paso, Texas, USA. The particle-tracking survey was used to better define filtration parameters. Several simulations were generated to allow visualization of the effects of well placement and pumping rate on flow paths, travel time, the size of the pumping influence zone, and proportion of river-derived water and groundwater mixing in the pumping well. Simulations indicate that migration of river water into the aquifer is generally slow. Most water does not arrive at the well by the end of an 18-day pumping period at 0.54 m3/min pumping rate for a well located 18 m from the river. Forty-four percent of the water pumped from the well was river water. The models provided important information needed to design appropriate sampling schedules for bank filtration practices and ensured meeting adequate soil-retention times. The pumping rate has more effect on river water travel time than the location of the pumping well from the river. The examples presented in this paper indicate that operating the pumping well at a doubled distance from the river increased the time required for the water to travel to the well, but did not greatly change the capture zone.

  20. An Aquifer Storage and Recovery system with reclaimed wastewater to preserve native groundwater resources in El Paso, Texas.

    PubMed

    Sheng, Zhuping

    2005-06-01

    The traditional concept of Aquifer Storage and Recovery (ASR) has been emphasized and extensively applied for water resources conservation in arid and semi-arid regions using groundwater systems as introduced in Pyne's book titled Groundwater Recharge and Wells. This paper extends the ASR concept to an integrated level in which either treated or untreated surface water or reclaimed wastewater is stored in a suitable aquifer through a system of spreading basins, infiltration galleries and recharge wells; and part or all of the stored water is recovered through production wells, dual function recharge wells, or by streams receiving increased discharge from the surrounding recharged aquifer as needed. In this paper, the author uses the El Paso Water Utilities (EPWU) ASR system for injection of reclaimed wastewater into the Hueco Bolson aquifer as an example to address challenges and resolutions faced during the design and operation of an ASR system under a new ASR system definition. This new ASR system concept consists of four subsystems: source water, storage space-aquifer, recharge facilities and recovery facilities. Even though facing challenges, this system has successfully recharged approximately 74.7 million cubic meters (19.7 billion gallons) of reclaimed wastewater into the Hueco Bolson aquifer through 10 recharge wells in the last 18 years. This ASR system has served dual purposes: reuse of reclaimed wastewater to preserve native groundwater, and restoration of groundwater by artificial recharge of reclaimed wastewater into the Hueco Bolson aquifer.

  1. Dento-alveolar lesions and palaeodietary inferences from the Paso Alsina 1 site (eastern Pampean-Patagonian transition, Argentina).

    PubMed

    Flensborg, G

    2011-10-01

    Several archaeological researches in northeastern Patagonia and southeastern Pampas have evaluated various indicators of the diets of hunter-gatherers who inhabited these regions during the Late Holocene, including the role of plant foods. Dental analysis is an important way to introduce new information about subsistence. In this sense, the objective of this work is to document and interpret dento-alveolar lesions in an osteological sample recovered from the Paso Alsina 1 archaeological site (eastern Pampean-Patagonian transition, Argentina). This paper will explore the oral health status of individuals and discuss palaeodietary information of hunter-gatherers that inhabited the lower valley of the Colorado River during the final Late Holocene (ca. 500 years BP). The site is defined as a formal area bundle composed of 10 secondary multiple burials containing 56 individuals of both sexes and various ages (e.g., perinatal, infant, and adult). In this study, 781 teeth and 1036 alveoli from 47 maxillae and 38 mandibles were analysed from 51 adult individuals. The results indicate a moderate rate of dental wear, and dental calculus, and low percentages of caries, abscesses, and antemortem tooth loss. The information obtained suggests a diet based on a combination of proteins, fat and carbohydrates. Results are then compared with those from other lines of analysis for the study area and for the neighboring regions (northeastern Patagonia and southeastern Pampas). PMID:21924417

  2. Comparison of two carbonate mound sequences in the Lower Ordovician El Paso Formation, west Texas and southern New Mexico

    SciTech Connect

    Clemons, R.E.

    1985-01-01

    The El Paso Formations consists of four members, in ascending order: Hitt Canyon, Jose McKelligon and Padre. Mounds in the McKelligon Member exposed in the southern Franklin Mountains were described by Toomey (1970). Most of these mounds are small but one large one is 5.8 m thick and about 13.7 m long in outcrop. The mound rock is chiefly bioclastic wackestone with minor packstone and boundstone. The varied fauna contains echinoderms, sponges and spicules, gastropods, trilobites, digitate algae, Nuia, Girvanella, Pulchrilamina, Calathium, and minor brachiopods and cephalopods. Intraclastic, bioclastic grainstone fills channels cut in the mounds. Similar, but smaller and less spectacular mounds occur in the McKelligon Member in the Florida, Big Hatchet, and Caballo Mountains, Lone Mountain, Cooke's Range, and elsewhere in southwestern New Mexico. A second type of mound is common in the upper part of the Hitt Canyon Member in the Cooke's Range, Red Hills, Caballo and Big Hatchet Mountains. These mounds also are typically small but one in the Red Hills is 13.7 m thick and about 30 m long in outcrop. The mound complex is about 75-80% SH-C and LLH-C stromatolite boundstone and bioclastic wackestone. The remaining 20-25% is bioclastic packstone and grainstone between the SH-C stromatolites and filling channels cut in the mound complex. The limited fauna contains small fragments of echinoderms, gastropods, trilobites, spicules, and Nuia.

  3. Utilizing Continuous Resistivity Profiling for Assessment and Characterization of Canal Seepage in El Paso's Lower Valley Irrigation Network System

    NASA Astrophysics Data System (ADS)

    Brown, W. A.; Sheng, Z.

    2009-12-01

    Annually, billions of gallons of water are lost through seepage along sections of the irrigation network. To conserve water, El Paso County Water Improvement District has been assessing seepage losses and investigating measures for reducing such losses. Resistivity techniques were used to identify areas of high seepage and provide information on locations along canals that need to be structurally modified in an effort to curb water lost through seepage. Several half mile sections were selected along canals with varying seepage rates to conduct electric resistivity surveys in order generate soil profiles during the non-irrigation and irrigation seasons. Two different multiple channel resistivity meters (The“OhmMapper and the Super Sting R8”) were used, which both allow a vertical resistivity profile to be collected using a single current transmission. The results presented are preliminary and we believe that upon completion findings will serve multiple purposes. Firstly, a better understanding of seepage patterns, seepage rate and its spatial variation can be obtained. Secondly, our findings could be used to produce geological profiles associated with seepage areas which will enable the irrigation district to develop guidelines for improving delivery efficiency, especially during drought. And thirdly, our results will be transferable to other areas of the state and will have a positive impact on the environment and the overall quality of life.

  4. Integrated Analysis of the Hydrology of a Mitigated Wetland in El Paso,Texas Utilizing Water Quality and Electrical Conductivity

    NASA Astrophysics Data System (ADS)

    Gonzalez, R.; Lucero, M.; Villalobos, J. I.; Doser, D. I.; Sheng, Z.; Wetland, Conductivity, Salinity, Water Quality

    2010-12-01

    Keystone Heritage Park (KHP) is a 52-acre nature preserve containing a natural wetland within city limits of El Paso, Texas. The source of water for the wetland has been an issue of interest as efforts to restore this wetland back to it native habit are currently underway. KHP is situated within the Mesilla Bolson - a Tertiary fault-block basin- and is adjacent to the Franklin mountains - a Laramide related fault block mountain range. The wetlands of Keystone are located in the shallow water bearing zones within the Mesilla Bolson which include the overlying Rio Grande Alluvium. It is thought the primary sources of groundwater and surface water for the KHP wetlands are by means of mountain-front recharge and through groundwater traveling south coming from the Rio Grande. The goal of this project was to identify possible locations of freshwater springs originating from these sources flowing into the wetlands. The project and data covered a period where the wetlands are at their driest (Dec.-May) due to winter weather and when they are at their fullest due to monsoonal rains (July- Aug.). By utilizing a Horiba portable pH/EC/TDS Meter quality of surface and groundwater was gathered throughout the wetlands at 14 sites. Preliminary results suggest several springs recharging the wetlands during both dry and wet periods. Further investigation of this result led to the use of an EM-31 data logger for conductivity data to better understand the relationships between groundwater, surface water, soil properties, and the mobilization of minerals entering the wetlands.

  5. Integrated Analysis of the Hydrology of a Mitigated Wetland Utilizing Water Quality and Electrical Conductivity in El Paso Texas

    NASA Astrophysics Data System (ADS)

    Gonzalez, R.; Lucero, M.; Villalobos, J. I.; Doser, D. I.; Sheng, Z.

    2011-12-01

    Keystone Heritage Park (KHP) is a 52-acre nature preserve containing a natural wetland within city limits of El Paso, Texas. The source of water for the wetland has been an issue of interest as efforts to restore this wetland back to it native habit are currently underway. KHP is situated within the Mesilla Bolson - a Tertiary fault-block basin- and is adjacent to the Franklin mountains - a Laramide related fault block mountain range. The wetlands of Keystone are located in the shallow water bearing zones within the Mesilla Bolson which includes the overlying Rio Grande Alluvium. It is thought the primary sources of groundwater and surface water for the KHP wetlands are by means of mountain-front recharge and through groundwater traveling south coming from the Rio Grande. The goal of this project was to identify possible locations of freshwater springs originating from these sources flowing into the wetlands. The project and data covered a period where the wetlands are at their driest (Dec.-May) due to winter weather and when they are at their fullest due to monsoonal rains (July- Aug.). By utilizing a Horiba portable pH/EC/TDS Meter quality of surface and groundwater was gathered throughout the wetlands at 14 sites. Preliminary results suggest several springs recharging the wetlands during both dry and wet periods. Further investigation of this result led to the use of an EM-31 data logger for conductivity data to better understand the relationships between groundwater, surface water, soil properties, and the mobilization of minerals entering the wetlands.

  6. GIS-modeled indicators of traffic-related air pollutants and adverse pulmonary health among children in El Paso, Texas.

    PubMed

    Svendsen, Erik R; Gonzales, Melissa; Mukerjee, Shaibal; Smith, Luther; Ross, Mary; Walsh, Debra; Rhoney, Scott; Andrews, Gina; Ozkaynak, Halûk; Neas, Lucas M

    2012-10-01

    Investigators examined 5,654 children enrolled in the El Paso, Texas, public school district by questionnaire in 2001. Exposure measurements were first collected in the late fall of 1999. School-level and residence-level exposures to traffic-related air pollutants were estimated using a land use regression model. For 1,529 children with spirometry, overall geographic information system (GIS)-modeled residential levels of traffic-related ambient air pollution (calibrated to a 10-ppb increment in nitrogen dioxide levels) were associated with a 2.4% decrement in forced vital capacity (95% confidence interval (CI): -4.0, -0.7) after adjustment for demographic, anthropomorphic, and socioeconomic factors and spirometer/technician effects. After adjustment for these potential covariates, overall GIS-modeled residential levels of traffic-related ambient air pollution (calibrated to a 10-ppb increment in nitrogen dioxide levels) were associated with pulmonary function levels below 85% of those predicted for both forced vital capacity (odds ratio (OR) = 3.10, 95% CI: 1.65, 5.78) and forced expiratory volume in 1 second (OR = 2.35, 95% CI: 1.38, 4.01). For children attending schools at elevations above 1,170 m, a 10-ppb increment in modeled nitrogen dioxide levels was associated with current asthma (OR = 1.56, 95% CI: 1.08, 2.50) after adjustment for demographic, socioeconomic, and parental factors and random school effects. These results are consistent with previous studies in Europe and California that found adverse health outcomes in children associated with modeled traffic-related air pollutants.

  7. Fluid‐driven seismicity response of the Rinconada fault near Paso Robles, California, to the 2003 M 6.5 San Simeon earthquake

    USGS Publications Warehouse

    Hardebeck, Jeanne L.

    2012-01-01

    The 2003 M 6.5 San Simeon, California, earthquake caused significant damage in the city of Paso Robles and a persistent cluster of aftershocks close to Paso Robles near the Rinconada fault. Given the importance of secondary aftershock triggering in sequences of large events, a concern is whether this cluster of events could trigger another damaging earthquake near Paso Robles. An epidemic‐type aftershock sequence (ETAS) model is fit to the Rinconada seismicity, and multiple realizations indicate a 0.36% probability of at least one M≥6.0 earthquake during the next 30 years. However, this probability estimate is only as good as the projection into the future of the ETAS model. There is evidence that the seismicity may be influenced by fluid pressure changes, which cannot be forecasted using ETAS. The strongest evidence for fluids is the delay between the San Simeon mainshock and a high rate of seismicity in mid to late 2004. This delay can be explained as having been caused by a pore pressure decrease due to an undrained response to the coseismic dilatation, followed by increased pore pressure during the return to equilibrium. Seismicity migration along the fault also suggests fluid involvement, although the migration is too slow to be consistent with pore pressure diffusion. All other evidence, including focal mechanisms and b‐value, is consistent with tectonic earthquakes. This suggests a model where the role of fluid pressure changes is limited to the first seven months, while the fluid pressure equilibrates. The ETAS modeling adequately fits the events after July 2004 when the pore pressure stabilizes. The ETAS models imply that while the probability of a damaging earthquake on the Rinconada fault has approximately doubled due to the San Simeon earthquake, the absolute probability remains low.

  8. Intracellular Na+ regulates epithelial Na+ channel maturation.

    PubMed

    Heidrich, Elisa; Carattino, Marcelo D; Hughey, Rebecca P; Pilewski, Joseph M; Kleyman, Thomas R; Myerburg, Mike M

    2015-05-01

    Epithelial Na(+) channel (ENaC) function is regulated by the intracellular Na(+) concentration ([Na(+)]i) through a process known as Na(+) feedback inhibition. Although this process is known to decrease the expression of proteolytically processed active channels on the cell surface, it is unknown how [Na(+)]i alters ENaC cleavage. We show here that [Na(+)]i regulates the posttranslational processing of ENaC subunits during channel biogenesis. At times when [Na(+)]i is low, ENaC subunits develop mature N-glycans and are processed by proteases. Conversely, glycan maturation and sensitivity to proteolysis are reduced when [Na(+)]i is relatively high. Surface channels with immature N-glycans were not processed by endogenous channel activating proteases, nor were they sensitive to cleavage by exogenous trypsin. Biotin chase experiments revealed that the immature surface channels were not converted into mature cleaved channels following a reduction in [Na(+)]i. The hypothesis that [Na(+)]i regulates ENaC maturation within the biosynthetic pathways is further supported by the finding that Brefeldin A prevented the accumulation of processed surface channels following a reduction in [Na(+)]i. Therefore, increased [Na(+)]i interferes with ENaC N-glycan maturation and prevents the channel from entering a state that allows proteolytic processing. PMID:25767115

  9. Illegal sales of cigarettes to minors--Ciudad Juárez, Mexico; El Paso, Texas; and Las Cruces, New Mexico, 1999.

    PubMed

    1999-05-21

    In 1996, the United States-Mexico Binational Commission (US-MBC) Health Working Group identified prevention of tobacco use, particularly among adolescents, as a priority and subsequently recommended joint efforts toward reducing illegal sales of cigarettes to minors. A 1997 survey of 561 commercial cigarette outlets in Mexico City found that 79% of retailers sold cigarettes to minors. To assess the illegal sale of cigarettes to minors in other regions of Mexico and on both sides of the U.S.-Mexico border, during January-February 1999 the General Directorate of Epidemiology in Mexico, the Chihuahua State Department of Health Services (CDH), the Ciudad Juarez Department of Health (CJDH), the Texas Department of Health (TDH), and the New Mexico Department of Health (NMDH) surveyed cigarette outlets in Ciudad Juarez, Mexico; El Paso, Texas; and Las Cruces, New Mexico. This report summarizes the results of these surveys, which indicate that almost all retailers in the surveyed outlets in Ciudad Juarez sold cigarettes to minors and that sales rates to minors were substantially lower in El Paso and Las Cruces.

  10. Seroprevalence of select bloodborne pathogens and associated risk behaviors among injection drug users in the Paso del Norte region of the United States – Mexico border

    PubMed Central

    Baumbach, Joan P; Foster, Lily N; Mueller, Mark; Cruz, Michelle Firestone; Arbona, Sonia; Melville, Sharon; Ramos, Rebeca; Strathdee, Steffanie A

    2008-01-01

    Background The region situated where the borders of Mexico, Texas and New Mexico meet is known as 'Paso del Norte'. The Paso del Norte Collaborative was formed to study the seroprevalence of select pathogens and associated risk behaviors among injection drug users (IDUs) in the region. Methods Respondent-driven sampling (RDS) was used: 459 IDU participants included 204 from Mexico; 155 from Texas; and 100 from New Mexico. Each of the three sites used a standardized questionnaire that was verbally administered and testing was performed for select bloodborne infections. Results Participants were mostly male (87.4%) and Hispanic/Latino (84.7%) whose median age was 38. In Mexico, Texas and New Mexico, respectively: hepatitis B virus (HBV) was seen in 88.3%, 48.6% and 59.6% of participants; hepatitis C virus (HCV) in 98.7%, 76.4% and 80.0%; human immunodeficiency virus (HIV) in 2.1%, 10.0% and 1.0%; and syphilis in 4.0%, 9.9% and 3.0%. Heroin was the drug injected most often. More IDUs in New Mexico were aware of and used needle exchange programs compared with Texas and Mexico. Conclusion There was mixed success using RDS: it was more successfully applied after establishing good working relationships with IDU populations. Study findings included similarities and distinctions between the three sites that will be used to inform prevention interventions. PMID:19014605

  11. Assessment of arsenic and heavy metal concentrations in water and sediments of the Rio Grande at El Paso-Juarez metroplex region.

    PubMed

    Rios-Arana, J V; Walsh, E J; Gardea-Torresdey, J L

    2004-01-01

    The Rio Grande located along the US-Mexico border is affected by anthropogenic activities along its geographical course. Runoff and wind deposition of smelting residues may contribute to the pollution of the Rio Grande in the El Paso-Ciudad Juarez area. Few studies have addressed the presence or impacts of heavy metals or arsenic in this ecosystem. This study reports a survey of heavy metals (Cr, Cu, Cd, Ni, Pb, and Zn) and arsenic (As) in water and sediments of the Rio Grande collected from seven sites in the El Paso-Juarez region. Since water quality influences metal content in water, physical (temperature, flow and conductivity), and chemical (pH, dissolved oxygen, nitrates, alkalinity, and water hardness) parameters were measured at each site. Arsenic and heavy metal levels were determined using Inductively Couple Plasma (ICP) emission spectroscopy following EPA procedures. Zinc and lead were found as both total and dissolved metals in most of the samples, with concentrations of total recoverable metals reaching up to 105 and 70 microg/l, respectively. Most metals were found in sediment samples collected from four of seven sites. The highest Cu concentration (35 mg/l) was found at the American Dam site. Concentrations of metals found through this survey will be used as a reference for future studies in monitoring arsenic, heavy metals, and their impacts in the Rio Grande.

  12. Urban development under extreme hydrologic and weather conditions for El Paso-Juarez: Recommendations resulting from hydrologic modeling, GIS, and remote sensing analyses

    NASA Astrophysics Data System (ADS)

    Barud-Zubillaga, Alberto

    During the 2006 El Paso-Juarez flood there were many concerns regarding the capability of the existing stormwater system to handle 50- and 100-year flood events in El Paso, Texas and Juarez, Mexico area. Moreover in 2008, a considerable wet year from the normal 223 mm of annual precipitation for El Paso demonstrated that the area could very well received large amounts of precipitation at localized areas in short periods of time, representing a great flood threat to residents living in areas prone to flood. Some climate change projections for the area are exactly what had occurred over the last two decades; an increased number of torrential rainstorms over smaller concentrated pieces of land separated by longer years of drought between rainstorms. This study consisted in three projects focused on three critical regions within the El Paso-Juarez area that were greatly affected by the 2006 Flood. The goal was to identify if natural arroyos or the existent built stormwater system, could properly managed the projected precipitation patterns. The three projects described in this dissertation touch on the following points: (a) the importance of a reliable precipitation model that could accurately describes precipitation patterns in the region under extreme drought and wet climates conditions; (b) differences in land use/land cover characteristics as factors promoting or disrupting the possibility for flooding, and (c) limitations and capabilities of existent stormwater systems and natural arroyos as means to control flooding. Conclusions and recommendations are shown below, which apply not only to each particular project, but also to all study areas and similar areas in the El Paso-Juarez region. Urbanization can improve or worsen a pre-existing natural stormwater system if built under its required capacity. Such capacity should be calculated considering extreme weather conditions, based on a denser network of precipitation stations to capture the various microclimates

  13. Digital model for simulated effects of ground-water pumping in the Hueco Bolson, El Paso Area, Texas, New Mexico, and Mexico

    USGS Publications Warehouse

    Meyer, W.R.

    1976-01-01

    The model study showed that a proposed plan of development for 1973-91, in which pumping would be increased by 29 percent in the Texas part of the bolson and by 34 percent in Ciudad Juarez, would cause additional waterlevel declines of as much as 45 feet (13.7 m) in the vicinity of El Paso and 70 feet (21.3 m) in Ciudad Juarez. The study also showed that nearly 60 percent of the water would come from storage in the water-table part of the bolson aquifer (model layer 2) and 28 percent from leakage from the alluvium (model layer 1). By the end of the period, 9.84 million acrefeet (12,133 hm3) of fresh water would be in storage in the Texas part of the bolson, as compared to 10.6 million acre-feet (13,070 hm3) in storage in 1973.

  14. Selected hydrologic data for the Mesilla ground-water basin, 1987 through 1992 water years, Dona Ana County, New Mexico, and El Paso County, Texas

    USGS Publications Warehouse

    Nickerson, Edward L.

    1995-01-01

    The Mesilla ground-water basin monitoring program was established in 1987 to document hydrologic conditions and establish a long-term, continuous data base to permit future quantitative evaluation of the ground-water flow system and stream/aquifer relations. Data collection is divided into three program elements. These are the (1) Mesilla ground- water basin observation-well program; (2) Mesilla Valley hydrologic sections; and (3) Rio Grande seepage investigations. This report is a compilation of hydrologic data collected for the Mesilla ground- water basin monitoring program during the 1987 through 1992 water years. Hydrologic data presented in the report include well records and water levels for 181 wells; mean daily river stage and ground- water levels at 37 sites; seepage investigations of the Rio Grande from Radium Springs, New Mexico, to El Paso, Texas; and chemical analyses of 29 water samples collected from the Rio Grande.

  15. Application of a stream-aquifer model to Monument Creek for development of a method to estimate transit losses for reusable water, El Paso County, Colorado

    USGS Publications Warehouse

    Kuhn, Gerhard; Arnold, L. Rick

    2006-01-01

    The U.S. Geological Survey, in cooperation with Colorado Springs Utilities, the Colorado Water Conservation Board, and the El Paso County Water Authority, began a study in 2004 to (1) apply a stream-aquifer model to Monument Creek, (2) use the results of the modeling to develop a transit-loss accounting program for Monument Creek, (3) revise the existing transit-loss accounting program for Fountain Creek to incorporate new water-management strategies and allow for incorporation of future changes in water-management strategies, and (4) integrate the two accounting programs into a single program with a Web-based user interface. The purpose of this report is to present the results of applying a stream-aquifer model to the Monument Creek study reach. More...

  16. Summary of water-quality data, October 1987 through September 1997, for Fountain and Monument Creeks, El Paso and Pueblo Counties, Colorado

    USGS Publications Warehouse

    Bossong, Clifford R.

    2001-01-01

    Fountain and Monument Creeks, which drain parts of El Paso and Pueblo Counties in Colorado, have been sampled systematically by the U.S. Geological Survey for many years to obtain records of water-quality properties and constituents; the data are stored in the National Water Inventory System. Statistical summaries of these data indicate that they have spatial and temporal trends. Comparison of water-quality data to in-stream regulatory standards, some of which were calculated in this report, indicate that some exceedances are widespread in the system and that some occur locally. Nonparametric tests to quantitatively detect monotonic trends in water-quality data indicate that many water-quality properties and constituents do not have significant monotonic trends; detected trends were mostly downward.

  17. Geohydrologic site characterization of the municipal solid waste landfill facility, US Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.

    1996-01-01

    Geohydrologic conditions of the Municipal Solid Waste Landfill Facility (MSWLF) on the U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas, were evaluated by the U.S. Geological Survey in cooperation with the U.S. Army. The 106.03-acre MSWLF has been in operation since January 1974. The landfill contains household refuse, Post solid wastes, bulky items, grass and tree trimmings from family housing, refuse from litter cans, construction debris, classified waste (dry), dead animals, asbestos, and empty oil cans. The MSWLF, located about 1,200 feet east of the nearest occupied structure, is estimated to receive an average of approximately 56 tons of municipal solid waste per day and, at a fill rate of 1-4 acres per year, is expected to reach its capacity by the year 2004. The MSWLF is located in the Hueco Bolson, 4 miles east of the Franklin Mountains. Elevations at the MSWLF range from 3,907 to 3,937 feet above sea level. The climate at the MSWLF and vicinity is arid continental, characterized by an abundance of sunny days, high summer temperatures, relatively cool winters typical of arid areas, scanty rainfall, and very low humidity throughout the year. Average annual temperature near the MSWLF and vicinity is 63.3 degrees Fahrenheit and annual precipitation is 7.8 inches. Potential evaporation in the El Paso area was estimated to be 65 inches per year. Soils at and adjacent to the MSWLF are nearly level to gently sloping, have a fine sandy loam subsoil, and are moderately deep over caliche. The MSWLF is underlain by Hueco Bolson deposits of Tertiary age and typically are composed of unconsolidated to slightly consolidated interbedded sands, clay, silt, gravel, and caliche. Individual beds are not well defined and range in thickness from a fraction of an inch to about 100 feet. The primary source of ground water in the MSWLF area is in the deposits of the Hueco Bolson. A relatively thick vadose zone of approximately 300 feet overlies the

  18. Hydrogeology and ground-water quality of the Chromic Acid Pit site, US Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Thomas, C.L.

    1996-01-01

    The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation, in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was certified closed in 1989 and the Texas Natural Resources Conservation Commission issued Permit Number HW-50296 (U.S. Environmental Protection Agency Permit Number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in evaluating hydrogeologic conditions and ground- water quality at the site. One upgradient and two downgradient ground-water monitoring wells were installed adjacent to the chromic acid pit by a private contractor. Quarterly ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The Chromic Acid Pit site is situated in the Hueco Bolson intermontane valley. The Hueco Bolson is a primary source of ground water in the El Paso area. City of El Paso and U.S. Army water-supply wells are located on all sides of the study area and are completed 600 to more than 1,200 feet below land surface. The ground-water level in the area of the Chromic Acid Pit site has declined about 25 feet from 1982 to 1993. Depth to water at the Chromic Acid Pit site in September 1994 was about 284 feet below land surface; ground-water flow is to the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site contained dissolved-solids concentrations of 442 to 564 milligrams per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.7 milligrams per liter; nitrite plus nitrate as nitrogen

  19. Hydrogeology and simulation of flow between the alluvial and bedrock aquifers in the upper Black Squirrel Creek basin, El Paso County, Colorado

    USGS Publications Warehouse

    Watts, K.R.

    1995-01-01

    Anticipated increases in pumping from the bedrock aquifers in El Paso County potentially could affect the direction and rate of flow between the alluvial and bedrock aquifers and lower water levels in the overlying alluvial aquifer. The alluvial aquifer underlies about 90 square miles in the upper Black Squirrel Creek Basin of eastern El Paso County. The alluvial aquifer consists of unconsolidated alluvial deposits that unconformably overlie siltstones, sandstones, and conglomerate (bedrock aquifers) and claystone, shale, and coal (bedrock confining units) of the Denver Basin. The bedrock aquifers (Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers) are separated by confining units (upper and lower Denver and the Laramie confining units) and overlie a relatively thick and impermeable Pierre confining unit. The Pierre confining unit is assumed to be a no-flow boundary at the base of the alluvial/ bedrock aquifer system. During 1949-90, substantial water-level declines, as large as 50 feet, in the alluvial aquifer resulted from withdrawals from the alluvial aquifer for irrigation and municipal supplies. Average recharge to the alluvial aquifer from infiltration of precipitation and surface water was an estimated 11.97 cubic feet per second and from the underlying bedrock aquifers was an estimated 0.87 cubic foot per second. Water-level data from eight bedrock observation wells and eight nearby alluvial wells indicate that, locally, the alluvial and bedrock aquifers probably are hydraulically connected and that the alluvial aquifer in the upper Black Squirrel Creek Basin receives recharge from the Denver and Arapahoe aquifers but-locally recharges the Laramie-Fox Hills aquifer. Subsurface-temperature profiles were evaluated as a means of estimating specific discharge across the bedrock surface (the base of the alluvial aquifer). However, assumptions of the analytical method were not met by field conditions and, thus, analyses of subsurface-temperature profiles

  20. Spatial and Temporal Variations in Streamflow and Dissolved Solids in the Rio Grande from Del Norte, Colorado, to El Paso, Texas, 1993-95

    NASA Astrophysics Data System (ADS)

    Moore, S. J.; Anderholm, S. K.

    2002-12-01

    Data collected as part of the Rio Grande Valley National Water Quality Assessment Program were used to evaluate spatial and temporal variations in streamflow and the concentration of dissolved solids at selected sites on the Rio Grande from Del Norte, Colorado, to El Paso, Texas, for the period of April 1993 to September 1995. Dissolved solids loads, which were estimated by a multivariate linear regression model (ESTIMATOR2000), are also presented and discussed. Spatial and temporal variations in streamflow, dissolved solids concentrations, and dissolved solids loads were used to evaluate how surface-water and ground-water inflows to and outflows from the Rio Grande affect dissolved solids along the river. Streamflow decreases from Del Norte, Colorado, to the mouth of the Conejos River because of diversions for irrigation. Streamflow increases from the mouth of the Conejos River to Otowi Bridge because of surface-water inflows (from the Conejos River, the Chama River, and other tributaries) and ground-water inflow in northern New Mexico. Streamflow decreases downstream from Otowi Bridge because outflows (due to agricultural use, leakage to ground water, and evapo-transpiration) are greater than inflows. Dissolved solids concentrations generally increase in the downstream direction; however, dissolved solids concentrations decrease between the mouth of the Conejos River and Otowi Bridge due to surface-water inflows from the Conejos and the Chama Rivers and ground-water inflows in northern New Mexico. In several reaches of the Rio Grande, decreasing streamflow and increasing dissolved solids loads indicate the presence of inflows with large dissolved solids concentrations (relative to those of the Rio Grande immediately upstream from that inflow); this occurs (1) between Del Norte, Colorado, and the mouth of Trinchera Creek, near Lasauses, Colorado (2) between Otowi Bridge and San Marcial, New Mexico, and (3) between Leasburg, New Mexico, and El Paso, Texas

  1. Model input and output files for the simulation of time of arrival of landfill leachate at the water table, Municipal Solid Waste Landfill Facility, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Frenzel, Peter F.

    1999-01-01

    This report contains listings of model input and output files for the simulation of the time of arrival of landfill leachate at the water table from the Municipal Solid Waste Landfill Facility (MSWLF), about 10 miles northeast of downtown El Paso, Texas. This simulation was done by the U.S. Geological Survey in cooperation with the U.S. Department of the Army, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas. The U.S. Environmental Protection Agency-developed Hydrologic Evaluation of Landfill Performance (HELP) and Multimedia Exposure Assessment (MULTIMED) computer models were used to simulate the production of leachate by a landfill and transport of landfill leachate to the water table. Model input data files used with and output files generated by the HELP and MULTIMED models are provided in ASCII format on a 3.5-inch 1.44-megabyte IBM-PC compatible floppy disk.

  2. A profile of US-Mexico border mobility among a stratified random sample of Hispanics living in the El Paso-Juarez area.

    PubMed

    Lapeyrouse, L M; Morera, O; Heyman, J M C; Amaya, M A; Pingitore, N E; Balcazar, H

    2012-04-01

    Examination of border-specific characteristics such as trans-border mobility and transborder health service illuminates the heterogeneity of border Hispanics and may provide greater insight toward understanding differential health behaviors and status among these populations. In this study, we create a descriptive profile of the concept of trans-border mobility by exploring the relationship between mobility status and a series of demographic, economic and socio-cultural characteristics among mobile and non-mobile Hispanics living in the El Paso-Juarez border region. Using a two-stage stratified random sampling design, bilingual interviewers collected survey data from border residents (n = 1,002). Findings show that significant economic, cultural, and behavioral differences exist between mobile and non-mobile respondents. While non-mobile respondents were found to have higher social economic status than their mobile counterparts, mobility across the border was found to offer less acculturated and poorer Hispanics access to alternative sources of health care and other services.

  3. Estimated probabilities and volumes of postwildfire debris flows—A prewildfire evaluation for the Pikes Peak area, El Paso and Teller Counties, Colorado

    USGS Publications Warehouse

    Elliott, John G.; Ruddy, Barbara C.; Verdin, Kristine L.; Schaffrath, Keelin R.

    2012-01-01

    Debris flows are fast-moving, high-density slurries of water, sediment, and debris that can have enormous destructive power. Although debris flows, triggered by intense rainfall or rapid snowmelt on steep hillsides covered with erodible material, are a common geomorphic process in some unburned areas, a wildfire can transform conditions in a watershed with no recent history of debris flows into conditions that pose a substantial hazard to residents, communities, infrastructure, aquatic habitats, and water supply. The location, extent, and severity of wildfire and the subsequent rainfall intensity and duration cannot be known in advance; however, hypothetical scenarios based on empirical debris-flow models are useful planning tools for conceptualizing potential postwildfire debris flows. A prewildfire study to determine the potential for postwildfire debris flows in the Pikes Peak area in El Paso and Teller Counties, Colorado, was initiated in 2010 by the U.S. Geological Survey, in cooperation with the City of Colorado Springs, Colorado Springs Utilities. The study was conducted to provide a relative measure of which subwatersheds might constitute the most serious potential debris-flow hazards in the event of a large-scale wildfire and subsequent rainfall.

  4. Seepage investigations of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2006-13

    USGS Publications Warehouse

    Crilley, D.M.; Matherne, A.M.; Thomas, Nicole; Falk, S.E.

    2013-01-01

    Seepage investigations were conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to 2013 along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of studies conducted from 2006 to 2013 are presented in this report. Seepage investigations were conducted over a period of 1–2 days in February of each year, during low-flow conditions in the non-irrigation season. During the seepage investigations, discharge was measured at as many as 24 sites along the Rio Grande and as many as 20 inflow sites within the study reach. Net seepage gain or loss was computed for each subreach by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be significant when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. Study reaches during 2006 to 2013 ranged from 20.2 to 64 miles in length, and seepage losses ranged from 8.2 ± 3.1 to 47.9 ± 8.2 cubic feet per second.

  5. Aquifer tests in the flood-plain alluvium and Santa Fe group at the Rio Grande near Canutillo, El Paso County, Texas

    USGS Publications Warehouse

    Nickerson, Edward L.

    1989-01-01

    An aquifer system consisting of the Rio Grande flood-plain alluvium and Santa Fe Group underlying the southern Mesilla Valley in Dona Ana County, New Mexico and El Paso County, Texas has become an important source of water for both municipal and agricultural uses. Determination of aquifer properties is essential in order to evaluate groundwater potential for increasing water demand and potential streamflow depletion of the Rio Grande due to groundwater development. The aquifer system at the Canutillo well field hydrologic section was divided into a shallow, intermediate, and deep zone based on geohydrologic characteristics. Aquifer properties of specific zones at the test site were determined from a series of multiple-well aquifer tests conducted from December 3, 1985 through January 20, 1986. The Rio Grande is hydraulically connected to the shallow flood-plain alluvium. Water generally occurs within the shallow zone under unconfined conditions, within the intermediate zone under semiconfined conditions, and within the deep zone under confined conditions. (USGS)

  6. Sources and Spatial Distribution of Metal Pollutants in Soils near the El Paso Smelter: A Forensic Study with Pb and Pu Isotopes.

    NASA Astrophysics Data System (ADS)

    Ketterer, Michael; Moan, Matthew; Gremillion, Paul

    2010-05-01

    Lead and copper smelting has been conducted at El Paso since the late 1800's, and as a result, environmental media near the smelter have become contaminated. A study has been conducted to investigate the sources and spatial distribution of metal pollutants (Pb, Cd, Zn, Hg, As, Cu) and concomitant tracers (Ag, In, Sb, Bi) in soils from the smelter vicinity. Sampled locations were residential and non-residential locations in El Paso (Texas, USA), Anapra (New Mexico, USA) and Ciudad Juarez (Chihuahua, Mexico). Lead isotope studies indicate that the soil Pb is derived from smelting, and is consistent with two-component mixing between lead ores from Chihuahua (northern Mexico) having 206Pb/204Pb of 18.6 - 18.8 and ores from the Hanover, New Mexico (USA) mining district with 206Pb/204Pb of ~ 17.6. The Pb isotope results also exclude other common anthropogenic Pb sources such as paint and gasoline emissions as being major contributors. Concentrations of Hg and Pb of up to 10 and 11,000 ppm were found in surface soils within 1 km of the smelter. The metal concentration results clearly indicate that soils near the smelter (< 5 km) exhibit much higher concentrations of smelter-related elements than do soils from control locations (> 10 km distant). A general trend of decreasing concentrations vs. distance from the smelter was also observed. However, the results indicate that metal concentrations vary widely even at a fixed distance from the smelter point source. This phenomenon results from a combination of natural and anthropogenic processes that disturb and re-distribute soils in the surface environment. The site conditions consist of a very arid environment with little vegetation cover that is frequently disturbed by high winds and severe episodic rainfall. To study these effects, we have investigated stratospheric fallout plutonium (239+240Pu) as a proxy measure of disturbed vs. undisturbed soil conditions. The premise is that 'undisturbed' locations will have high 239

  7. Combustion-generated nanoparticulates in the El Paso, TX, USA / Juarez, Mexico Metroplex: their comparative characterization and potential for adverse health effects.

    PubMed

    Murr, L E; Soto, K F; Garza, K M; Guerrero, P A; Martinez, F; Esquivel, E V; Ramirez, D A; Shi, Y; Bang, J J; Venzor, J

    2006-03-01

    In this paper we report on the collection of fine (PM1) and ultrafine (PM0.1), or nanoparticulate, carbonaceous materials using thermophoretic precipitation onto silicon monoxide/formvar-coated 3 mm grids which were examined in the transmission electron microscope (TEM). We characterize and compare diesel particulate matter (DPM), tire particulate matter (TPM), wood burning particulate matter, and other soot (or black carbons (BC)) along with carbon nanotube and related fullerene nanoparticle aggregates in the outdoor air, as well as carbon nanotube aggregates in the indoor air; and with reference to specific gas combustion sources. These TEM investigations include detailed microstructural and microdiffraction observations and comparisons as they relate to the aggregate morphologies as well as their component (primary) nanoparticles. We have also conducted both clinical surveys regarding asthma incidence and the use of gas cooking stoves as well as random surveys by zip code throughout the city of El Paso. In addition, we report on short term (2 day) and longer term (2 week) in vitro assays for black carbon and a commercial multiwall carbon nanotube aggregate sample using a murine macrophage cell line, which demonstrate significant cytotoxicity; comparable to a chrysotile asbestos nanoparticulate reference. The multi-wall carbon nanotube aggregate material is identical to those collected in the indoor and outdoor air, and may serve as a surrogate. Taken together with the plethora of toxic responses reported for DPM, these findings prompt concerns for airborne carbonaceous nanoparticulates in general. The implications of these preliminary findings and their potential health effects, as well as directions for related studies addressing these complex issues, will also be examined.

  8. Seepage investigation of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2014

    USGS Publications Warehouse

    Briody, Alyse C.; Robertson, Andrew J.; Thomas, Nicole

    2016-03-22

    Seepage investigations have been conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to the present (2014) along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of the investigation conducted in 2014 are presented in this report. The 2014 seepage investigation was conducted on February 11, 2014, during the low-flow conditions of the non-irrigation season. During the 2014 investigation, discharge was measured at 23 sites along the main-stem Rio Grande and 19 inflow sites within the study reach. Because of extended drought conditions affecting the basin, many sites along the Rio Grande (17 main-stem and 9 inflow) were observed to be dry in February 2014. Water-quality samples were collected during the seepage investigation at sites with flowing water as part of a long-term monitoring effort in the region.Net seepage gain or loss was computed for each subreach (the interval between two adjacent measurement locations along the river) by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be meaningful when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. The cumulative seepage loss in the 64-mile study reach in 2014 was 16.0 plus or minus 2.9 cubic feet per second.

  9. Analysis of a Multi-Well Tracer Test at a Bank Filtration Site in an Arid Environment of El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, A. N.; Langford, R.; Schulze-Makuch, D.; Sheng, Z.

    2005-12-01

    River bank filtered water is an important component of the drinking water production in many areas of the world. In riverbank filtration, the removal of pathogens is an important task for the production of good quality drinking water. The hydrogeological factors and spatial changes in the water's microbiology during the transport from the river to the aquifer have important implications on the quality of the produced water. The goal of this study was to investigate riverbank infiltration effectiveness in arid environments such as that of El Paso, Texas. The hydrostratigraphic units and hydrogeologic conditions were characterized with lithologic samples obtained from all boreholes collected during the construction of twelve observation wells and one production well in the site, which were constructed near the artificial stream to provide geologic and hydrologic information. The shallow aquifer is composed of three unites: high hydraulic conductivity layers on the top and bottom, and low conductivity layer in the middle. In this study advective transport of microspheres was compared with a conservative tracer such as bromide. Bromide was injected into an observation well at the channel margin. Simultaneously, 1, 6 and 10 micron-diameter fluorescent microspheres equivalent to Giardia, Cryptosporidium, and bacteria sizes were injected into the stream bottom and two observation wells to assess the suitability of microspheres as abiotic analogs in future investigations involving the physical aspects of bacteria and protozoa transport behavior. The 17.8 day-tracer test provided valuable results that are relevant to the transport of pathogens through the subsurface under riverbank filtration conditions. The 1 micron-size microspheres were abundant in the pumping and observation wells and showed multiple peaks similar to the bromide results. Microspheres from the three injection sites had distinctly different transport paths and rates. The 6 and 10 micron-size microspheres

  10. Protegiendo a su familia de los terremotos-Los siete pasos a la seguridad para prepararse en caso de un terremoto (en espa?ol y en ingles)

    USGS Publications Warehouse

    Desarrollado por American Red Cross, Asian Pacific Fund

    2007-01-01

    Les escribimos esta carta para comunicarle un mensaje sumamente importante sobre las preparaciones de emergencia. Historicamente, hemos sufrido terremotos aqui en el Area de la Bahia de San Francisco que han causado graves privaciones para los residentes de la comunidad y da?os increibles a nuestras ciudades. Es probable que suframos un terremoto de gran magnitud en los proximos 30 a?os. Muchos de nosotros venimos de otros paises donde hemos pasado por terremotos y por eso creemos entenderlos. Sin embargo, la manera que nos preparamos para terremotos en nuestros paises de origen puede ser distinta a la que empleamos aca en los Estados Unidos. Muy pocas personas mueren a causa de los derrumbes de los edificios en el Area de la Bahia porque la mayoria de los edificios son construidos para resistir el sacudimiento de la tierra. Pero es muy probable que su familia no tenga atencion medica, alimentos o que esten separados del uno al otro por dias o semanas. Finalmente depende de usted mantener a su familia a salvo hasta que llegue asistencia, por eso les pedimos que nos unamos para aprender a cuidar a su familia antes, durante, y despues de un terremoto. El primer paso es leer este libro. Cada uno de su familia, ni?os y adultos, pueden aprender como prepararse para un terremoto. Haga participar e incluya sus ni?os; pueden ayudarle a prepararse. Aproveche las clases ofrecidas en su comunidad sobre las preparaciones de terremotos por la Cruz Roja Estadounidense (American Red Cross). Estos cursos de preparacion son gratis y disponibles en espa?ol para todos en la comunidad sin tomar en cuenta la historia de la familia, estado legal, genero o edad. Les recomendamos que tome ventaja de estas clases gratuitas. Para mas informacion consulte la ultima pagina de este libro. Recuerde que un terremoto puede ocurrir sin aviso y la unica manera de reducir el da?o de terremotos es estar preparados. !Preparese!

  11. Geologic and hydrologic data for the municipal solid waste landfill facility, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Frenzel, P.F.

    1999-01-01

    Geologic and hydrologic data for the Municipal Solid Waste Landfill Facility on the U.S. Army Air Defense Artillery Center and Fort Bliss in El Paso County, Texas, were collected by the U.S. Geological Survey in cooperation with the U.S. Department of the Army. The 106.03-acre landfill has been in operation since January 1974. The landfill contains household refuse, Post solid wastes, bulky items, grass and tree trimmings from family housing, refuse from litter cans, construction debris, classified waste (dry), dead animals, asbestos, and empty oil cans. The depth of the filled areas is about 30 feet and the cover, consisting of locally derived material, is 2 to 3 feet thick. Geologic and hydrologic data were collected at or adjacent to the landfill during (1) drilling of 10 30- to 31-foot boreholes that were completed with gas-monitoring probes, (2) drilling of a 59-foot borehole, (3) drilling of a 355-foot borehole that was completed as a ground-water monitoring well, and (4) in situ measurements made on the landfill cover. After completion, the gas- monitoring probes were monitored on a quarterly basis (1 year total) for gases generated by the landfill. Water samples were collected from the ground-water monitoring well for chemical analysis. Data collection is divided into two elements: geologic data and hydrologic data. Geologic data include lithologic descriptions of cores and cuttings, geophysical logs, soil- gas and ambient-air analyses, and chemical analyses of soil. Hydrologic data include physical properties, total organic carbon, and pH of soil and sediment samples; soil-water chloride and soil-moisture analyses; physical properties of the landfill cover; measurements of depth to ground water; and ground-water chemical analyses. Interpretation of data is not included in this report.

  12. Geohydrology, water quality, and preliminary simulations of ground-water flow of the alluvial aquifer in the Upper Black Squirrel Creek basin, El Paso County, Colorado

    USGS Publications Warehouse

    Buckles, D.R.; Watts, K.R.

    1988-01-01

    The upper Black Squirrel Creek basin in eastern El Paso County, Colorado, is underlain by an alluvial aquifer and four bedrock aquifers. Groundwater pumpage from the alluvial aquifer has increased since the mid-1950's, and water level declines have been substantial; the bedrock aquifers virtually are undeveloped. Groundwater pumpage for domestic, stock, agricultural, and municipal uses have exceeded recharge for the past 25 years. The present extent of the effect of pumpage on the alluvial aquifer was evaluated, and a groundwater flow model was used to simulate the future effect of continued pumpage on the aquifer. Measured water level declines from 1974 through 1984 were as much as 30 ft in an area north of Ellicott, Colorado. On the basis of the simulations, water level declines from October 1984 to April 1999 north of Ellicott might be as much as 20 to 30 ft and as much as 1 to 10 ft in most of the aquifer. The groundwater flow models provided a means of evaluating the importance of groundwater evapotranspiration at various stages of aquifer development. Simulated groundwater evapotranspiration was about 43% of the outflow from the aquifer during predevelopment stages but was less than 3% of the outflow from the aquifer during late-development stages. Analyses of 36 groundwater samples collected during 1984 indicated that concentrations of dissolved nitrite plus nitrate as nitrogen generally were large. Samples from 5 of the 36 wells had concentrations of dissolved nitrite plus nitrate as nitrogen that exceeded drinking water standards. Water from the alluvial aquifer generally is of suitable quality for most uses. (USGS)

  13. Description and User Manual for a Web-Based Interface to a Transit-Loss Accounting Program for Monument and Fountain Creeks, El Paso and Pueblo Counties, Colorado

    USGS Publications Warehouse

    Kuhn, Gerhard; Krammes, Gary S.; Beal, Vivian J.

    2007-01-01

    The U.S. Geological Survey, in cooperation with Colorado Springs Utilities, the Colorado Water Conservation Board, and the El Paso County Water Authority, began a study in 2004 with the following objectives: (1) Apply a stream-aquifer model to Monument Creek, (2) use the results of the modeling to develop a transit-loss accounting program for Monument Creek, (3) revise an existing accounting program for Fountain Creek to easily incorporate ongoing and future changes in management of return flows of reusable water, and (4) integrate the two accounting programs into a single program and develop a Web-based interface to the integrated program that incorporates simple and reliable data entry that is automated to the fullest extent possible. This report describes the results of completing objectives (2), (3), and (4) of that study. The accounting program for Monument Creek was developed first by (1) using the existing accounting program for Fountain Creek as a prototype, (2) incorporating the transit-loss results from a stream-aquifer modeling analysis of Monument Creek, and (3) developing new output reports. The capabilities of the existing accounting program for Fountain Creek then were incorporated into the program for Monument Creek and the output reports were expanded to include Fountain Creek. A Web-based interface to the new transit-loss accounting program then was developed that provided automated data entry. An integrated system of 34 nodes and 33 subreaches was integrated by combining the independent node and subreach systems used in the previously completed stream-aquifer modeling studies for the Monument and Fountain Creek reaches. Important operational criteria that were implemented in the new transit-loss accounting program for Monument and Fountain Creeks included the following: (1) Retain all the reusable water-management capabilities incorporated into the existing accounting program for Fountain Creek; (2) enable daily accounting and transit

  14. Evaluation of emission control strategies to reduce ozone pollution in the Paso del Norte region using a photochemical air quality modeling system

    NASA Astrophysics Data System (ADS)

    Valenzuela, Victor Hugo

    variability of the PREDICTED to OBSERVED ozone concentrations of both BASELINE model and simulations with modified emissions assessed by the sensitivity analysis. All simulations were found to vary within acceptable ranges of these two criteria variables. Simulation results indicate ozone formation in the PdN region is VOC-limited. Under VOC-limited conditions, modifications to NOx emissions do not produce a marked increase or decrease in ozone concentrations. Modifications to VOC emissions generated the highest variability in ozone concentrations. Increasing VOC emissions by 75% produced results which minimized model bias and error when comparing PREDICTED and OBSERVED ozone concentrations. Increasing VOC emissions by 75% either alone or in combination with a 75% increase in NOx emissions generated PREDICTED ozone concentrations very near to OBSERVED ozone. By evaluating the changes in ambient ozone concentrations through photochemical modeling, air quality planners may identify the most efficient or effective VOC emissions control strategies for area sources. Among the strategies to achieve emissions reductions are installation of gasoline vapor recovery systems, replacing high-pressure low-volume surface coating paint spray guns with high-volume low-pressure spray paint guns, requiring emissions control booths for surface coating operations as well as undertaking solvent management practices, requiring the sale of low VOC paint solvents in the surface-coating industry, and requiring low-VOC solvents in the dry cleaning industry. Other strategies to reduce VOC emissions include initiating Eco-Driving strategies to reduce fuel consumption from mobile sources and minimize vehicle idling at the international ports of entry by reducing bridge wait times. This dissertation depicts a tool for evaluating impacts of emissions on regional air quality by addressing the highly unresolved fugitive emissions in the Paso del Norte region. It provides a protocol for decision makers to

  15. Na+ coordination at the Na2 site of the Na+/I- symporter.

    PubMed

    Ferrandino, Giuseppe; Nicola, Juan Pablo; Sánchez, Yuly E; Echeverria, Ignacia; Liu, Yunlong; Amzel, L Mario; Carrasco, Nancy

    2016-09-13

    The sodium/iodide symporter (NIS) mediates active I(-) transport in the thyroid-the first step in thyroid hormone biosynthesis-with a 2 Na(+): 1 I(-) stoichiometry. The two Na(+) binding sites (Na1 and Na2) and the I(-) binding site interact allosterically: when Na(+) binds to a Na(+) site, the affinity of NIS for the other Na(+) and for I(-) increases significantly. In all Na(+)-dependent transporters with the same fold as NIS, the side chains of two residues, S353 and T354 (NIS numbering), were identified as the Na(+) ligands at Na2. To understand the cooperativity between the substrates, we investigated the coordination at the Na2 site. We determined that four other residues-S66, D191, Q194, and Q263-are also involved in Na(+) coordination at this site. Experiments in whole cells demonstrated that these four residues participate in transport by NIS: mutations at these positions result in proteins that, although expressed at the plasma membrane, transport little or no I(-) These residues are conserved throughout the entire SLC5 family, to which NIS belongs, suggesting that they serve a similar function in the other transporters. Our findings also suggest that the increase in affinity that each site displays when an ion binds to another site may result from changes in the dynamics of the transporter. These mechanistic insights deepen our understanding not only of NIS but also of other transporters, including many that, like NIS, are of great medical relevance.

  16. NURE aerial gamma-ray and magnetic reconnaissance survey of portions of New Mexico, Arizona and Texas. Volume II. Texas-New Mexico-El Paso NH 13-1 Quadrangle. Final report

    SciTech Connect

    Not Available

    1981-09-01

    The results of a high-sensitivity, aerial gamma-ray spectrometer and magnetometer survey of the El Paso, two degree quadrangle, New Mexico, are presented. Instrumentation and methods are described in Volume I of this final report. The work was done by Carson Helicopters Inc., and Carson Helicopters was assisted in the interpretation by International Exploration, Inc. The work was performed for the US Department of Energy - National Uranium Resource Evaluation (NURE) program. A total of 72 statistically significant eU anomalies were identified in this quadrangle. Of this number 20 were considered to be of sufficient intensity to warrant field investigations, however, many of these anomalies appear to be wholly, or in part, associated with various unconsolidated Quaternary deposits. Only three of the 20 can, with certainty be identified with bedrock; one with a Quaternary flow, one with Cambrian sandstone and one with a Precambrian granite.

  17. Na Cauda do Cometa

    NASA Astrophysics Data System (ADS)

    Voelzke, M. R.

    2009-01-01

    Quando viam um cometa, os antigos gregos imaginavam uma estrela com uma vasta cabeleira. Não à toa, a palavra deriva do termo koma, que significa cabelo. Constituídos por fragmentos de gelo e gases, os cometas possuem um núcleo sólido, que pode ter vários quilômetros de diâmetro, e uma cauda que sempre aponta na direção contrária ao Sol, devido aos ventos solares. Graças à aparência de pontos luminosos em movimento (ao contrário de outros astros, que parecem estáticos), esses corpos celestes foram interpretados por diferentes povos com muito misticismo, inspirando mitos tanto de boas-novas como de maus presságios. Conheça algumas dessas histórias:

  18. Regulation of the epithelial Na(+) channel by intracellular Na(+).

    PubMed

    Awayda, M S

    1999-08-01

    The hypothesis that the intracellular Na(+) concentration ([Na(+)](i)) is a regulator of the epithelial Na(+) channel (ENaC) was tested with the Xenopus oocyte expression system by utilizing a dual-electrode voltage clamp. [Na(+)](i) averaged 48.1 +/- 2.2 meq (n = 27) and was estimated from the amiloride-sensitive reversal potential. [Na(+)](i) was increased by direct injection of 27.6 nl of 0.25 or 0.5 M Na(2)SO(4). Within minutes of injection, [Na(+)](i) stabilized and remained elevated at 97.8 +/- 6.5 meq (n = 9) and 64. 9 +/- 4.4 (n = 5) meq 30 min after the initial injection of 0.5 and 0.25 M Na(2)SO(4), respectively. This increase of [Na(+)](i) caused a biphasic inhibition of ENaC currents. In oocytes injected with 0.5 M Na(2)SO(4) (n = 9), a rapid decrease of inward amiloride-sensitive slope conductance (g(Na)) to 0.681 +/- 0.030 of control within the first 3 min and a secondary, slower decrease to 0.304 +/- 0.043 of control at 30 min were observed. Similar but smaller inhibitions were also observed with the injection of 0.25 M Na(2)SO(4). Injection of isotonic K(2)SO(4) (70 mM) or isotonic K(2)SO(4) made hypertonic with sucrose (70 mM K(2)SO(4)-1.2 M sucrose) was without effect. Injection of a 0.5 M concentration of either K(2)SO(4), N-methyl-D-glucamine (NMDG) sulfate, or 0.75 M NMDG gluconate resulted in a much smaller initial inhibition (<14%) and little or no secondary decrease. Thus increases of [Na(+)](i) have multiple specific inhibitory effects on ENaC that can be temporally separated into a rapid phase that was complete within 2-3 min and a delayed slow phase that was observed between 5 and 30 min. PMID:10444397

  19. Solidification of NaCl-NaF eutectic in space

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Yu, J. G.

    1974-01-01

    Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, have been produced in space and on earth, respectively. The production of continuous fibers in a eutectic mixture was attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It was found that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis.

  20. Optical properties of NaCl-NaF eutectics

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Yu, J. G.

    1976-01-01

    A new concept is advanced to explain the phenomenon of transmittance versus far-field infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelength is known. Experimental data are in excellent agreement with the theoretical prediction.

  1. Na+ recirculation and isosmotic transport.

    PubMed

    Larsen, E H; Møbjerg, N

    2006-01-01

    The Na(+) recirculation theory for solute-coupled fluid absorption is an expansion of the local osmosis concept introduced by Curran and analyzed by Diamond & Bossert. Based on studies on small intestine the theory assumes that the observed recirculation of Na(+) serves regulation of the osmolarity of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability in proximal tubule of AQP1 (-/-) mice, and the inverse relationship between hydraulic permeability and the concentration difference needed to reverse transepithelial water flow. The model reproduces the volume responses of cells and lateral intercellular space (lis) following replacement of luminal NaCl by sucrose as well as the linear dependence of volume absorption on luminal NaCl concentration. Analysis of solvent drag on Na(+) in tight junctions provides explanation for the surprisingly high metabolic efficiency of Na(+) reabsorption. The model predicts and explains low metabolic efficiency in diluted external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and < or = 1 mOsm in proximal tubule. Truly isosmotic transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation of apical Na(+) uptake, which is not included in the mathematical treatment. PMID:17206513

  2. Na+ recirculation and isosmotic transport.

    PubMed

    Larsen, E H; Møbjerg, N

    2006-01-01

    The Na(+) recirculation theory for solute-coupled fluid absorption is an expansion of the local osmosis concept introduced by Curran and analyzed by Diamond & Bossert. Based on studies on small intestine the theory assumes that the observed recirculation of Na(+) serves regulation of the osmolarity of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability in proximal tubule of AQP1 (-/-) mice, and the inverse relationship between hydraulic permeability and the concentration difference needed to reverse transepithelial water flow. The model reproduces the volume responses of cells and lateral intercellular space (lis) following replacement of luminal NaCl by sucrose as well as the linear dependence of volume absorption on luminal NaCl concentration. Analysis of solvent drag on Na(+) in tight junctions provides explanation for the surprisingly high metabolic efficiency of Na(+) reabsorption. The model predicts and explains low metabolic efficiency in diluted external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and < or = 1 mOsm in proximal tubule. Truly isosmotic transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation of apical Na(+) uptake, which is not included in the mathematical treatment.

  3. Characterization of Anthropogenic Land Subsidence, its Relation to Fault System Geometry, and Their Consequences for Water Table Position in the El Paso, Texas Area Using InSAR and Gravity

    NASA Astrophysics Data System (ADS)

    Schiek, C. G.; Leuro, E.; Buckley, S.; Hurtado, J. M.

    2006-12-01

    The Hueco and Mesilla basins, located in the westernmost part of Texas and the southernmost part of New Mexico, are part of the Rio Grande Aquifer system. This aquifer system is the major water source for New Mexico, west Texas, and Mexico, including the cities of El Paso and Ciudad Juarez. The aquifer system lies within the Rio Grande Rift system, which spans the eastern edge of the Basin and Range province. Normal faults defining the Rio Grande Rift put structural and stratigraphic controls on aquifer systems such as those in the Mesilla and Hueco basins. These faults define stratigraphic controls on the aquifer by placing compacted rock next to unconsolidated and unsorted sediments, and act as conduits for water flow from the surface to the subsurface. We combine InSAR and gravity measurements to determine the location and geometry of subsurface faults within the basins. These faults can determine the shape and extent of observed land subsidence, which is a consequence of increased water pumping since the early 20th century. In addition, hydrologic information about the Rio Grande aquifer system, such as aquifer flow, compaction, and basin stratigraphy are compared with the InSAR results in order to determine how the subsidence is affecting the water table. Finally, subsidence patterns can indicate the presence and geometry of subsurface faults that may pose seismic hazards.

  4. Use of InSAR to identify land-surface displacements caused by aquifer-system compaction in the Paso Robles area, San Luis Obispo County, California, March to August 1997

    USGS Publications Warehouse

    Valentine, D.W.; Densmore, J.N.; Galloway, D.L.; Amelung, Falk

    2000-01-01

    The population in San Luis Obispo County has grown steadily during the 1990s, and some land use has been converted from dry farming to grazing to irrigated vineyards and urban areas. Because insufficient surface-water supplies are available to meet the growing demand, ground-water pumpage has increased and the resulting water-level declines have raised concern that this water resource may become overstressed. One particular concern is whether the larger ground-water basins within the county function as large individual basins or whether subsurface structures divide these large basins into smaller subbasins, as differences in ground-water-level data suggest. Interferometric Synthetic Aperture Radar (InSAR) is used in locating land-surface displacement, which may indicate subsurface structures in ground-water basins by determining seasonal and historical land-surface changes. Owing to the high spatial detail of InSAR imagery, the InSAR-derived displacement maps can be used with ground-water-level data to reveal differential aquifer-system compaction related to the presence of geological structures or the distribution of compressible sediments that may define subbasin boundaries. This report describes InSAR displacement maps of the Paso Robles area of San Luis Obispo County and compares them to maps of seasonal changes in ground-water levels to detect the presence of aquifer-system compaction.

  5. Use of InSAR to identify land-surface displacements caused by aquifer-system compaction in the Paso Robles area, San Luis Obispo County, California, March to August 1997

    USGS Publications Warehouse

    Valentine, David W.; Densmore, Jill N.; Galloway, Devin L.; Amelung, Falk

    2001-01-01

    The population in San Luis Obispo County has grown steadily during the 1990s, and some land use has been converted from dry farming to grazing to irrigated vineyards and urban areas. Because insufficient surface-water supplies are available to meet the growing demand, ground-water pumpage has increased and the resulting water-level declines have raised concern that this water resource may become overstressed. One particular concern is whether the larger ground-water basins within the county function as large individual basins or whether subsurface structures divide these large basins into smaller subbasins, as differences in ground-water-level data suggest. Interferometric Synthetic Aperture Radar (InSAR) is used in locating land-surface displacement, which may indicate subsurface structures in ground-water basins by determining seasonal and historical land-surface changes. Owing to the high spatial detail of InSAR imagery, the InSAR-derived displacement maps can be used with ground-water-level data to reveal differential aquifer-system compaction related to the presence of geological structures or the distribution of compressible sediments that may define subbasin boundaries. This report describes InSAR displacement maps of the Paso Robles area of San Luis Obispo County and compares them to maps of seasonal changes in ground-water levels to detect the presence of aquifer-system compaction.

  6. Drugs preventing Na+ and Ca2+ overload.

    PubMed

    Ravens, U; Himmel, H M

    1999-03-01

    Cardiac intracellular Na+and Ca2+homeostasis is regulated by the concerted action of ion channels, pumps and exchangers. The Na+, K+-ATPase produces the electrochemical concentration gradient for Na+, which is the driving force for Ca2+removal from the cytosol via the Na+/Ca2+exchange. Reduction of this gradient by increased intracellular Na+concentration leads to cellular Ca2+overload resulting in arrhythmias and contractile dysfunction. Na+and Ca2+overload-associated arrhythmias can be produced experimentally by inhibition of Na+efflux (digitalis-induced intoxication) and by abnormal Na+influx via modulated Na+channels (veratridine, DPI 201-106; hypoxia) or via the Na+, H+exchanger. Theoretically, blockers of Na+and Ca2+channels, inhibitors of abnormal oscillatory release of Ca2+from internal stores or modulators of the Na+, Ca2+and Na+, H+exchanger activities could protect against cellular Na+and Ca2+overload. Three exemplary drugs that prevent Na+and Ca2+overload, i.e. the benzothiazolamine R56865, the methylenephenoxydioxy-derivative CP-060S, and the benzoyl-guanidine Hoe 642, a Na+, H+exchange blocker, are briefly reviewed with respect to their efficacy on digitalis-, veratridine- and ischaemia/reperfusion-induced arrhythmias. PMID:10094840

  7. Na Deposition on MnO(100)

    NASA Astrophysics Data System (ADS)

    Feng, Xu; Cox, David F.

    2016-03-01

    Na deposition on the MnO(100) surface was investigated by temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and low energy electron diffraction (LEED). Na TPD and XPS results indicate that adsorbed Na interacts strongly with the MnO substrate to form an irreversibly-adsorbed, oxidic Na compound on the surface for coverages up to 1 monolayer (ML). This strongly-bound Na diffuses into the MnO subsurface and bulk at elevated temperatures above 500 K. For Na coverages above 1 ML, metallic Na is present and desorbs from the surface below 500 K. The deposition of Na on MnO(100) follows a Stranski-Krastanov (SK) growth mode, with the formation of metallic Na islands following completion of the first Na monolayer. After Na deposition, the surface exhibits a diffuse (1 × 1) LEED pattern, suggesting the formation of disordered Na overlayers. After heating to 1000 K, the surface presents a (2 × 2) LEED pattern indicating that a surface reconstruction is induced by the diffusion of Na into the near surface region. CO2 can be used as a probe molecule in TPD to distinguish between metallic Na islands and oxidic Na in the first ML, and to indicate when Na that is still observable by XPS goes subsurface.

  8. β decay of Na32

    NASA Astrophysics Data System (ADS)

    Mattoon, C. M.; Sarazin, F.; Hackman, G.; Cunningham, E. S.; Austin, R. A. E.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Koopmans, K. A.; Leslie, J. R.; Phillips, A. A.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Svensson, C. E.; Waddington, J. C.; Walker, P. M.; Washbrook, B.; Zganjar, E.

    2007-01-01

    The β-decay of Na32 has been studied using β-γ coincidences. New transitions and levels are tentatively placed in the level scheme of Mg32 from an analysis of γ-γ and β-γ-γ coincidences. The observation of the indirect feeding of the 2321 keV state in Mg32 removes some restrictions previously placed on the spin assignment for this state. No evidence of a state at 2117 keV in Mg32 is found. Previously unobserved weak transitions up to 5.4 MeV were recorded but could not be placed in the decay scheme of Na32.

  9. Interactions of external and internal H+ and Na+ with Na+/Na+ and Na+/H+ exchange of rabbit red cells: evidence for a common pathway.

    PubMed

    Morgan, K; Canessa, M

    1990-12-01

    We have studied the kinetic properties of rabbit red cell (RRBC) Na+/Na+ and Na+/H+ exchanges (EXC) in order to define whether or not both transport functions are conducted by the same molecule. The strategy has been to determine the interactions of Na+ and H+ at the internal (i) and external (o) sites for both exchanges modes. RRBC containing varying Nai and Hi were prepared by nystatin and DIDS treatment of acid-loaded cells. Na+/Na+ EXC was measured as Nao-stimulated Na+ efflux and Na+/H+ EXC as Nao-stimulated H+ efflux and delta pHo-stimulated Na+ influx into acid-loaded cells. The activation of Na+/Na+ EXC by Nao at pHi 7.4 did not follow simple hyperbolic kinetics. Testing of different kinetic models to obtain the best fit for the experimental data indicated the presence of high (Km 2.2 mM) and low affinity (Km 108 mM) sites for a single- or two-carrier system. The activation of Na+/H+ EXC by Nao (pHi 6.6, Nai less than 1 mM) also showed high (Km 11 mM) and low (Km 248 mM) affinity sites. External H+ competitively inhibited Na+/Na+ EXC at the low affinity Nao site (KH 52 nM) while internally H+ were competitive inhibitors (pK 6.7) at low Nai and allosteric activators (pK 7.0) at high Nai. Na+/H+ EXC was also inhibited by acid pHo and allosterically activated by Hi (pK 6.4). We also established the presence of a Nai regulatory site which activates Na+/H+ and Na+/Na+ EXC modifying the affinity for Nao of both pathways. At low Nai, Na+/Na+ EXC was inhibited by acid pHi and Na+/H+ stimulated but at high Nai, Na+/Na+ EXC was stimulated and Na+/H+ inhibited being the sum of both pathways kept constant. Both exchange modes were activated by two classes of Nao sites, cis-inhibited by external Ho, allosterically modified by the binding of H+ to a Hi regulatory site and regulated by Nai. These findings are consistent with Na+/Na+ EXC being a mode of operation of the Na+/H+ exchanger. Na+/H+ EXC was partially inhibited (80-100%) by dimethyl-amiloride (DMA) but basal or

  10. Is there a Hispanic Health Paradox in Sensitivity to Air Pollution? Hospital Admissions for Asthma, Chronic Obstructive Pulmonary Disease and Congestive Heart Failure Associated with NO2 and PM2.5 in El Paso, TX, 2005–2010

    PubMed Central

    Herrera, Juana M.; Bulathsinhala, Priyangi; Staniswalis, Joan G.

    2015-01-01

    Study Objective Linkages between pollution and morbidity have been observed in numerous studies. But race/ethnicity has been underemphasized as a modifier of that association, and few studies have tested for a Hispanic Health Paradox in sensitivity to air pollution. Methods Daily asthma, chronic obstructive pulmonary disease (COPD) and congestive heart failure (CHF) hospital admissions in El Paso, Texas were studied in age groups and insurance groups. Daily PM2.5 and NO2 were calculated from pollution monitors and all models adjusted for apparent temperature and wind speed. Conditional logistic regression for the case-crossover design was used for a between-group comparison and for a within-group comparison for Hispanics. Results Hispanics were at lower risk than non-Hispanic whites and non-Hispanics of other races for NO2-associated admissions, but at greater risk for PM2.5-associated admissions. While Hispanics were generally protected with regards to NO2, Hispanic children (vs. elderly) faced increased risk for asthma and uninsured Hispanics (vs. Private) faced increased risk for COPD admissions. While Hispanics were at increased risk of PM2.5-associated admissions, certain characteristics heightened their risks: being a Hispanic child (vs. Elderly) for asthma; being a Hispanic with Medicare (vs. Private) for asthma; and being a Hispanic with private insurance (vs. all other insurance types) for CHF. The main effect of pollution on admissions was more significant for asthma and CHF than for COPD, which had the fewest cases. Conclusions There was heterogeneity in sensitivity to air pollution based on social characteristics and moderate evidence for a Hispanic Health Paradox in sensitivity to NO2. PMID:26557023

  11. The NA62 trigger system

    NASA Astrophysics Data System (ADS)

    Krivda, M.; NA62 Collaboration

    2013-08-01

    The main aim of the NA62 experiment (NA62 Technical Design Report, na62.web.cern.ch/NA62/Documents/TD_Full_doc_v1.pdf> [1]) is to study ultra-rare Kaon decays. In order to select rare events over the overwhelming background, central systems with high-performance, high bandwidth, flexibility and configurability are necessary, that minimize dead time while maximizing data collection reliability. The NA62 experiment consists of 12 sub-detector systems and several trigger and control systems, for a total channel count of less than 100,000. The GigaTracKer (GTK) has the largest number of channels (54,000), and the Liquid Krypton (LKr) calorimeter shares with it the largest raw data rate (19 GB/s). The NA62 trigger system works with 3 trigger levels. The first trigger level is based on a hardware central trigger unit, so-called L0 Trigger Processor (L0TP), and Local Trigger Units (LTU), which are all located in the experimental cavern. Other two trigger levels are based on software, and done with a computer farm located on surface. The L0TP receives information from triggering sub-detectors asynchronously via Ethernet; it processes the information, and then transmits a final trigger decision synchronously to each sub-detector through the Trigger and Timing Control (TTC) system. The interface between L0TP and the TTC system, which is used for trigger and clock distribution, is provided by the Local Trigger Unit board (LTU). The LTU can work in two modes: global and stand-alone. In the global mode, the LTU provides an interface between L0TP and TTC system. In the stand-alone mode, the LTU can fully emulate L0TP and so provides an independent way for each sub-detector for testing or calibration purposes. In addition to the emulation functionality, a further functionality is implemented that allows to synchronize the clock of the LTU with the L0TP and the TTC system. For testing and debugging purposes, a Snap Shot Memory (SSM) interface is implemented, that can work

  12. Europlanet NA2 Science Networking

    NASA Astrophysics Data System (ADS)

    Harri, Ari-Matti; Szego, Karoly; Genzer, Maria; Schmidt, Walter; Krupp, Norbert; Lammer, Helmut; Kallio, Esa; Haukka, Harri

    2013-04-01

    Europlanet RI / NA2 Science Networking [1] focused on determining the major goals of current and future European planetary science, relating them to the Research Infrastructure that the Europlanet RI project [2] developed, and placing them in a more global context. NA2 also enhanced the ability of European planetary scientists to participate on the global scene with their own agenda-setting projects and ideas. The Networking Activity NA2 included five working groups, aimed at identifying key science issues and producing reference books on major science themes that will bridge the gap between the results of present and past missions and the scientific preparation of the future ones. Within the Europlanet RI project (2009-2012) the NA2 and NA2-WGs organized thematic workshops, an expert exchange program and training groups to improve the scientific impact of this Infrastructure. The principal tasks addressed by NA2 were: • Science activities in support to the optimal use of data from past and present space missions, involving the broad planetary science community beyond the "space club" • Science activities in support to the preparation of future planetary missions: Earth-based preparatory observations, laboratory studies, R&D on advanced instrumentation and exploration technologies for the future, theory and modeling etc. • Develop scientific activities, joint publications, dedicated meetings, tools and services, education activities, engaging the public and industries • Update science themes and addressing the two main scientific objectives • Prepare and support workshops of the International Space Science Institute (ISSI) in Bern and • Support Trans National Activities (TNAs), Joined Research Activities (JRAs) and the Integrated and Distributed Information Service (IDIS) of the Europlanet project These tasks were achieved by WG workshops organized by the NA2 working groups, by ISSI workshops and by an Expert Exchange Program. There were 17 official WG

  13. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    SciTech Connect

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; Nam, Kyung -Wan; Guo, Yu -Guo

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmosphere during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.

  14. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    DOE PAGESBeta

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; Nam, Kyung -Wan; Guo, Yu -Guo

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmospheremore » during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.« less

  15. Ionic regulation of Na absorption in proximal colon: cation inhibition of electroneutral Na absorption

    SciTech Connect

    Sellin, J.H.; De Soignie, R.

    1987-01-01

    Active Na absorption (J/sub net//sup NA/) in rabbit proximal colon in vitro is paradoxically stimulated as (Na) in the bathing media is lowered with constant osmolarity. J/sub m..-->..s//sup Na/ increases almost linearly from 0 to 50 mM (Na)/sub 0/ but then plateaus and actually decreases from 50 to 140 mM (Na)/sub 0/, consistent with inhibition of an active transport process. Both lithium and Na are equally effective inhibitors of J/sub net//sup Na/, whereas choline and mannitol do not block the high rate of J/sub net//sup Na/ observed in decreased (Na)/sub 0/. Either gluconate or proprionate replacement of Cl inhibits J/sub net//sup Na/. J/sub net//sup Na/ at lowered (Na)/sub 0/ is electrically silent and is accompanied by increased Cl absorption; it is inhibited by 10/sup -3/ M amiloride and 10/sup -3/ theophylline but not by 10/sup -4/ M bumetanide. Epinephrine is equally effective at stimulating Na absorption at 50 and 140 mM (Na). Na gradient experiments are consistent with a predominantly serosal effect of the decreased (Na)/sub 0/. These results suggest that 1) Na absorption in rabbit proximal colon in vitro is stimulated by decreased (Na); 2) the effect is cation specific, both Na and Li blocking the stimulatory effect; 3) the transport is mediated by Na-H exchange and is Cl dependent but 4) is under different regulatory mechanisms than the epinephrine-sensitive Na-Cl cotransport previously described in proximal colon. Under the appropriate conditions, proximal colon absorbs Na extremely efficiently. Na-H exchange in this epithelium is cation inhibitable, either directly or by a secondary regulatory process.

  16. Single crystal growth of type I Na-Si clathrate by using Na-Sn flux

    NASA Astrophysics Data System (ADS)

    Morito, Haruhiko; Shimoda, Masashi; Yamane, Hisanori

    2016-09-01

    Single crystals of type I Na-Si clathrate, Na8Si46, were synthesized by heating Na, Na4Si4, and Na15Sn4 at 723 K under an Ar gas pressure of 104 Pa for 12 h. The single crystals having {110} habit planes grew up to 1.5 mm in size due to Na evaporation from a Na-Si-Sn melt with a starting compositional molar ratio of Na/Si/Sn=5.75:2:1.

  17. Deliquescence of NaCl-NaNO3 and KNO3-NaNO3 Salt Mixtures at 90C

    SciTech Connect

    Carroll, S; Craig, L; Wolery, T

    2003-12-29

    We conducted reversed deliquescence experiments in saturated NaCl-NaNO3-H2O and KNO{sub 3}-NaNO{sub 3}-H{sub 2}O systems at 90 C to determine relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Model predictions agree with experimental results for the NaCl-NaNO{sub 3}-H{sub 2}O system, but underestimate relative humidity by as much as 8% and solution composition by as much as 50% in the KNO{sub 3}-NaNO{sub 3}-H{sub 2}O system.

  18. Compensatory regulation of Na+ absorption by Na+/H+ exchanger and Na+-Cl- cotransporter in zebrafish (Danio rerio)

    PubMed Central

    2013-01-01

    Introduction In mammals, internal Na+ homeostasis is maintained through Na+ reabsorption via a variety of Na+ transport proteins with mutually compensating functions, which are expressed in different segments of the nephrons. In zebrafish, Na+ homeostasis is achieved mainly through the skin/gill ionocytes, namely Na+/H+ exchanger (NHE3b)-expressing H+-ATPase rich (HR) cells and Na+-Cl- cotransporter (NCC)-expressing NCC cells, which are functionally homologous to mammalian proximal and distal convoluted tubular cells, respectively. The present study aimed to investigate whether or not the functions of HR and NCC ionocytes are differentially regulated to compensate for disruptions of internal Na+ homeostasis and if the cell differentiation of the ionocytes is involved in this regulation pathway. Results Translational knockdown of ncc caused an increase in HR cell number and a resulting augmentation of Na+ uptake in zebrafish larvae, while NHE3b loss-of-function caused an increase in NCC cell number with a concomitant recovery of Na+ absorption. Environmental acid stress suppressed nhe3b expression in HR cells and decreased Na+ content, which was followed by up-regulation of NCC cells accompanied by recovery of Na+ content. Moreover, knockdown of ncc resulted in a significant decrease of Na+ content in acid-acclimated zebrafish. Conclusions These results provide evidence that HR and NCC cells exhibit functional redundancy in Na+ absorption, similar to the regulatory mechanisms in mammalian kidney, and suggest this functional redundancy is a critical strategy used by zebrafish to survive in a harsh environment that disturbs body fluid Na+ homeostasis. PMID:23924428

  19. The hydrogen storage properties of Na decorated small boron cluster B6Na8

    NASA Astrophysics Data System (ADS)

    Tang, Chunmei; Wang, Zhiguo; Zhang, Xue; Wen, Ninghua

    2016-09-01

    The binding energy of the Na atoms to the hollow sites of the B6 cage is larger than the experimental cohesive energy of bulk Na, so the clustering of Na atoms can be avoided. The polarization interaction dominates the adsorption of H2 by the B6Na8 cluster. The Na-coated B6Na8sbnd B8sbnd B6Na8 complex with the dispersive Na atoms and four H2 molecules adsorbed per Na can serve as better building blocks of polymers than the (B6Na8)2 dimer. These findings suggest a new route to design cluster-assembled hydrogen storage materials based on sp2-terminated boron chains.

  20. Silicene for Na-ion battery applications

    NASA Astrophysics Data System (ADS)

    Zhu, Jiajie; Schwingenschlögl, Udo

    2016-09-01

    Na-ion batteries are promising candidates to replace Li-ion batteries in large scale applications because of the advantages in natural abundance and cost of Na. Silicene has potential as the anode in Li-ion batteries but so far has not received attention with respect to Na-ion batteries. In this context, freestanding silicene, a graphene-silicene-graphene heterostructure, and a graphene-silicene superlattice are investigated for possible application in Na-ion batteries, using first-principles calculations. The calculated Na capacities of 954 mAh/g for freestanding silicene and 730 mAh/g for the graphene-silicene superlattice (10% biaxial tensile strain) are highly competitive and potentials of \\gt 0.3 {{V}} against the Na{}+/Na potential exceed the corresponding value of graphite. In addition, the diffusion barriers are predicted to be \\lt 0.3 {eV}.

  1. El Paso Electric photovoltaic-system analyses

    SciTech Connect

    Not Available

    1982-05-01

    Four analyses were performed on the Newman Power Station PV system. Two were performed using the Photovoltaic Transient Analysis Program (PV-TAP) and two with the SOLCEL II code. The first was to determine the optimum tilt angle for the array and the sensitivity of the annual energy production to variation in tilt angle. The optimum tilt angle was found to be 28/sup 0/, and variations of 2/sup 0/ produce losses of only 0.06% in the annual energy production. The second analysis assesses the power loss due to cell-to-cell variations in short circuit current and the degree of improvement attainable by sorting cells and matching modules. Typical distributions on short circuit current can cause losses of about 9.5 to 11 percent in peak array power, and sorting cells into 4 bins prior to module assembly can reduce the losses to about 6 to 8 percent. Using modules from the same cell bins in building series strings can reduce the losses to about 4.5 to 6 percent. Results are nearly the same if the array is operated at a fixed votage. The third study quantifies the magnitude and frequency of occurrence of high cell temperatures due to reverse bias caused by shadowing, and it demonstrates that cell temperatures achieved in reverse bias are higher for cells with larger shunt resistance. The last study assesses the adequacy of transient protection devices on the dc power lines to transients produced by array switching and lightning. Large surge capacitors on the dc power line effectively limit voltage excursions at the array and at the control room due to lightning. Without insertion of series resistors, the current may be limited only by cable and switch impedances, and all elements could be severely stressed. (LEW)

  2. The effect of Na vapor on the Na content of chondrules

    NASA Technical Reports Server (NTRS)

    Lewis, R. Dean; Lofgren, Gary E.; Franzen, Hugo F.; Windom, Kenneth E.

    1993-01-01

    Chondrules contain higher concentrations of volatiles (Na) than expected for melt droplets in the solar nebula. Recent studies have proposed that chondrules may have formed under non-canonical nebular conditions such as in particle/gas-rich clumps. Such chondrule formation areas may have contained significant Na vapor. To test the hypothesis of whether a Na-rich vapor would minimize Na volatilization reaction rates in a chondrule analog and maintain the Na value of the melt, experiments were designed where a Na-rich vapor could be maintained around the sample. A starting material with a melting point lower that typical chondrules was required to keep the logistics of working with Na volatilization from NaCl within the realm of feasibility. The Knippa basalt, a MgO-rich alkali olivine basalt with a melting temperature of 1325 +/- 5 C and a Na2O content of 3.05 wt%, was used as the chondrule analog. Experiments were conducted in a 1 atm, gas-mixing furnace with the fO2 controlled by a CO/CO2 gas mixture and fixed at the I-W buffer curve. To determine the extent of Na loss from the sample, initial experiments were conducted at high temperatures (1300 C - 1350 C) for duration of up to 72 h without a Na-rich vapor present. Almost all (up to 98%) Na was volatilized in runs of 72 h. Subsequent trials were conducted at 1330 C for 16 h in the presence of a Na-rich vapor, supplied by a NaCl-filled crucible placed in the bottom of the furnace. Succeeding Knudsen cell weight-loss mass-spectrometry analysis of NaCl determined the P(sub Na) for these experimental conditions to be in the 10(exp -6) atm range. This value is considered high for nebula conditions but is still plausible for non-canonical environments. In these trials the Na2O content of the glass was maintained or in some cases increased; Na2O values ranged from 2.62% wt to 4.37% wt. The Na content of chondrules may be controlled by the Na vapor pressure in the chondrule formation region. Most heating events capable

  3. Effect of colchicine on sensitivity of duck salt gland Na,K-ATPase to Na+.

    PubMed

    Yakushev, S S; Kumskova, E M; Rubtsov, A M; Lopina, O D

    2008-09-01

    Low molecular mass proteins of the FXYD family that affect the sensitivity of Na,K-ATPase to Na+ and K+ are known to be present in Na,K-ATPases in various tissues. In particular, in Na,K-ATPase from kidney a gamma-subunit (with electrophoretic mobility corresponding to molecular mass of about 10 kD) is present, and Na,K-ATPase preparations from heart contain phospholemman (electrophoretic mobility of this protein corresponds to molecular mass of 13-14 kD), which provides for the interaction of heart Na,K-ATPase with cytoskeletal microtubules. Disruption of microtubules by colchicine removes phospholemman from heart Na,K-ATPase preparations. The goal of the present study was to reveal a low molecular mass protein (probably a member of FXYD family) in preparation of Na,K-ATPase from duck salt glands. Immunoprecipitation of solubilized duck salt gland Na,K-ATPase using antibodies against alpha1-subunit results in the coprecipitation of a 13 kD protein with the Na,K-ATPase complex. Treatment of homogenate from duck salt glands with colchicine removes this protein from the purified preparation of Na,K-ATPase. Simultaneously, we observed a decrease in the sensitivity of Na,K-ATPase to Na+ at pH 6.5. However, colchicine treatment of homogenate from rabbit kidney does not affect either the sensitivity of Na,K-ATPase obtained from this homogenate to Na+ or the content of 10 kD protein (presumably gamma-subunit). The data suggest that phospholemman (or a similar member of the FXYD family) tightly interacts with Na,K-ATPase from duck salt glands and binds it to microtubules, simultaneously participating in the regulation of the sensitivity of Na,K-ATPase to Na+. PMID:18976215

  4. Growth of binary organic NLO crystals: m.NA-p.NA and m.NA-CNA system

    NASA Technical Reports Server (NTRS)

    Singh, N. B.; Henningsen, T.; Hopkins, R. H.; Mazelsky, R.

    1993-01-01

    Experiments were carried out to grow 3.Nitroaniline (m.NA) crystals doped with 4.Nitroaniline (p.NA) and 2.chloro 4.Nitroaniline (CNA). The measured undercooling for m.NA, p.NA, and CNA were 0.21 tm K, 0.23 tm K, and 0.35 tm K respectively, where tm represents the melting temperature of the pure component. Because of the crystals' large heat of fusion and large undercooling, it was not possible to grow good quality crystals with low thermal gradients. In the conventional two-zone Bridgman furnace we had to raise the temperature of the hot zone above the decomposition temperature of CNA, p.NA, and m.NA to achieve the desired thermal gradient. To avoid decomposition, we used an unconventional Bridgman furnace. Two immiscible liquids, silicone oil and ethylene glycol, were used to build a special two-zone Bridgman furnace. A temperature gradient of 18 K/cm was achieved without exceeding the decomposition temperature of the crystal. The binary crystals, m.NA-p.NA and m.NA-CNA, were grown in centimeter size in this furnace. X-ray and optical characterization showed good optical quality.

  5. Maintaining the Na atmosphere of Mercury

    NASA Technical Reports Server (NTRS)

    Killen, Rosemary M.; Morgan, Thomas H.

    1993-01-01

    The possible sources of the Na atmosphere of Mercury are calculatively studied. The likely structure, composition, and temperature of the planet's upper crust is examined along with the probable flux of Na from depth by grain boundary diffusion and by Knudsen flow. The creation of fresh regolith is considered along with mechanisms for supplying Na from the surface to the exosphere. The implications of the calculations for the probable abundances in the regolith are discussed.

  6. Colonic H(+)-K(+)-ATPase in K(+) conservation and electrogenic Na(+) absorption during Na(+) restriction.

    PubMed

    Spicer, Z; Clarke, L L; Gawenis, L R; Shull, G E

    2001-12-01

    Upregulation of the colonic H(+)-K(+)- ATPase (cHKA) during hyperaldosteronism suggests that it functions in both K(+) conservation and electrogenic Na(+) absorption in the colon when Na(+)-conserving mechanisms are activated. To test this hypothesis, wild-type (cHKA(+/+)) and cHKA-deficient (cHKA(-/-)) mice were fed Na(+)-replete and Na(+)-restricted diets and their responses were analyzed. In both genotypes, Na(+) restriction led to reduced plasma Na(+) and increased serum aldosterone, and mRNAs for the epithelial Na(+) channel (ENaC) beta- and gamma-subunits, channel-inducing factor, and cHKA were increased in distal colon. Relative to wild-type controls, cHKA(-/-) mice on a Na(+)-replete diet had elevated fecal K(+) excretion. Dietary Na(+) restriction led to increased K(+) excretion in knockout but not in wild-type mice. The amiloride-sensitive, ENaC-mediated short-circuit current in distal colon was significantly reduced in knockout mice maintained on either the Na(+)-replete or Na(+)-restricted diet. These results demonstrate that cHKA plays an important role in K(+) conservation during dietary Na(+) restriction and suggest that cHKA-mediated K(+) recycling across the apical membrane is required for maximum electrogenic Na(+) absorption. PMID:11705741

  7. Ionic dependence of active Na-K transport: "clamping" of cellular Na+ with monensin.

    PubMed

    Haber, R S; Pressley, T A; Loeb, J N; Ismail-Beigi, F

    1987-07-01

    The Na+ ionophore monensin was used to study the Na+- and K+-dependence of ouabain-inhibitable 86Rb+ uptake in ARL 15 cells, a rat liver cell line. Graded concentrations of monensin rapidly induced incremental elevations of cellular Na+ that were stable for up to 2 h. In experiments in which cellular Na+ was thus "clamped" at various levels, the activation curve for ouabain-inhibitable 86Rb+ uptake as a function of intracellular Na+ was found to be steepest near basal Na+ levels (Hill coefficient approximately equal to 2.4), indicating that these cells can respond to relatively large changes in passive Na+ entry by increasing the race of Na-K pump function with only minimal increases in cellular Na+. Exposure of cells to monensin also permitted examination of the extracellular-K+ dependence of ouabain-inhibitable 86Rb+ uptake in the presence of saturating intracellular Na+ and yielded a Hill coefficient of approximately 1.5. The rate of ATP hydrolysis calculated from measurements of the maximal rate of ouabain-inhibitable 86Rb+ uptake in intact cells was similar to the enzymatic Vmax of the Na+-K+-ATPase in cell lysates, suggesting that the Na+-K+-ATPase activity in these broken-cell preparations closely reflects the functional transport capacity of the Na-K pump.

  8. NA-NET numerical analysis net

    SciTech Connect

    Dongarra, J. |; Rosener, B.

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host ``na-net.ornl.gov`` at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message ``send index`` to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user`s perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  9. NA-NET numerical analysis net

    SciTech Connect

    Dongarra, J. . Dept. of Computer Science Oak Ridge National Lab., TN ); Rosener, B. . Dept. of Computer Science)

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host na-net.ornl.gov'' at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message send index'' to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user's perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  10. Painful Na-channelopathies: an expanding universe.

    PubMed

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic.

  11. NaHCO3 and NaC1 tolerance in chronic renal failure.

    PubMed

    Husted, F C; Nolph, K D; Maher, J F

    1975-08-01

    In patients with chronic renal failure, NaHCO3 therapy may correct or prevent acidemia. It has been proposed that the NaHCO3 required will not result in clinically significant Na retention comparable to that from similar increases in NaC1 intake. In each of ten patients with chronic renal failure, creatinine clearance (Ccr) range 2.5-16.8 ml/min, on an estimated 10-meq Na and C1 diet, electrolyte excretion was compared on NaHCO3 vs NaC1 supplements of 200 meq/day. Periods of NaHCO3 and NaC1 (in alternate order for successive patients) lasted 4 days, separated by reequilibration to base-line weight. Mean +/- SEM excretion (ex) of Na, C1, and HCO3 and deltaCcr and deltaweight (day 4-1) are compared below for the 4th day of NaC1 vs. NaHCO3 intake. Mean Ccr +/-SEM on day 4 of NaC1 and NaHCO3 were 10.8 +/-1.6 and 9.0 +/-1.4 ml/min, respectively (P less than 0.02). Mean systolic blood pressure (but not diastolic) increased significantly on NaC1 (P less than 0.05). No significant blood pressure changes were seen on NaHCO3. Net positive HCO3 balance occurred on NaHCO3 as indicated above and reflected a rise in mean serum HCO3 from 19 to 30 meq/liter (day 1 vs. 4) (P less than 0.01). Mechanisms for the greater excretion of Na on NaHCO3 may relate to C1 wasting as noted above on low C1 intake and limited HCO3 reabsorptive capacity. Thus, Na excretion by day 4 was greater on NaHCO3 than on NaHCO3 did Na excretion near intake (210 meq/day).

  12. Geohydrology of the unsaturated zone and simulated time of arrival of landfill leachate at the water table, municipal solid waste landfill facility, US Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Frenzel, Peter F.; Abeyta, Cynthia G.

    1999-01-01

    The U.S. Air Defense Artillery Center and Fort Bliss Municipal Solid Waste Landfill Facility (MSWLF) is located about 10 miles northeast of downtown El Paso, Texas. The landfill is built on the Hueco Bolson, a deposit that yields water to five public-supply wells within 1.1 miles of the landfill boundary on all sides. The bolson deposits consist of lenses and mixtures of sand, clay, silt, gravel, and caliche. The unsaturated zone at the landfill is about 300 feet thick. The Hydrologic Evaluation of Landfill Performance (HELP) and the Multimedia Exposure Assessment Model for Evaluating the Land Disposal of Wastes (MULTIMED) computer models were used to simulate the time of first arrival of landfill leachate at the water table. Site-specific data were collected for model input. At five sites on the landfill cover, hydraulic conductivity was measured by an in situ method; in addition, laboratory values were obtained for porosity, moisture content at field capacity, and moisture content at wilting point. Twenty-seven sediment samples were collected from two adjacent boreholes drilled near the southwest corner of the landfill. Of these, 23 samples were assumed to represent the unsaturated zone beneath the landfill. The core samples were analyzed in the laboratory for various characteristics required for the HELP and MULTIMED models: initial moisture content, dry bulk density, porosity, saturated hydraulic conductivity, moisture retention percentages at various suction values, total organic carbon, and pH. Parameters were calculated for the van Genuchten and Brooks-Corey equations that relate hydraulic conductivity to saturation. A reported recharge value of 0.008 inch per year was estimated on the basis of soil- water chloride concentration. The HELP model was implemented using input values that were based mostly on site-specific data or assumed in a conservative manner. Exceptions were the default values used for waste characteristics. Flow through the landfill was

  13. Ground-water quality, water year 1995, and statistical analysis of ground-water-quality data, water years 1994-95, at the Chromic Acid Pit site, US Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Roybal, R.G.

    1996-01-01

    The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was closed in 1989, and the Texas Natural Resources Conservation Commission issued permit number HW-50296 (U.S. Environmental Protection Agency number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in monitoring and evaluating ground-water quality at the site. One upgradient ground-water monitoring well (MW1) and two downgradient ground-water monitoring wells (MW2 and MW3), installed adjacent to the chromic acid pit, are monitored on a quarterly basis. Ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The ground-water level, measured in a production well located approximately 1,700 feet southeast of the Chromic Acid Pit site, has declined about 29.43 feet from 1982 to 1995. Depth to water at the Chromic Acid Pit site in September 1995 was 284.2 to 286.5 feet below land surface; ground-water flow at the water table is assumed to be toward the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site during water year 1995 contained dissolved- solids concentrations of 481 to 516 milligrams per liter. Total chromium concentrations detected above the laboratory reporting limit ranged from 0.0061 to 0.030 milligram per liter; dissolved chromium concentrations ranged from 0.0040 to 0.010 milligram per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.8 milligrams per

  14. Water-quality assessment of the Rio Grande Valley, Colorado, New Mexico and Texas; ground-water quality in the Rio Grande flood plain, Cochiti Lake, New Mexico, to El Paso, Texas, 1995

    USGS Publications Warehouse

    Bexfield, L.M.; Anderholm, S.K.

    1997-01-01

    From March to May of 1995, water samples were collected from 30 wells located in the flood plain of the Rio Grande between Cochiti Lake, New Mexico, and El Paso, Texas. These samples were analyzed for a broad host of constituents, including field parameters, major constituents, nutrients, dissolved organic carbon, trace elements, radiochemicals, pesticides, and volatile organic compounds. The main purpose of this study was to observe the quality of ground water in this part of the Rio Grande Valley study unit of the U.S. Geological Survey National Water-Quality Assessment program. The sampling effort was limited to the basin- fill aquifer beneath the above-defined reach of the Rio Grande flood plain because of the relative homogeneity of the hydrogeology, the large amount of ground-water use for public supply, and the potential for land-use activities to affect the quality of ground water. Most of the wells sampled for the study are used for domestic purposes, including drinking water. Depths to the tops of the sampling intervals in the 30 wells ranged from 10 to 345 feet below land surface, and the median was 161.5 feet; the sampling intervals in most of the wells spanned about 10 feet or less. Quality-control data were collected at three of the wells. A significant amount of variation was found in the chemical composition of ground water sampled throughout the study area, but the water generally was found to be of suitable chemical quality for use as drinking water, according to current enforceable standards established by the U.S. Environmental Protection Agency (EPA). Nutrients generally were measured at concentrations near or below their method reporting limits. The most dominant nutrient species was nitrite plus nitrate, at a maximum concentration of 1.9 milligrams per liter (as N). Only eight of the trace elements analyzed for had median concentrations greater than their respective minimum reporting levels. Water from one well exceeded the lifetime health

  15. Na+/Ca2+ exchange and Na+/K+-ATPase in the heart

    PubMed Central

    Shattock, Michael J; Ottolia, Michela; Bers, Donald M; Blaustein, Mordecai P; Boguslavskyi, Andrii; Bossuyt, Julie; Bridge, John H B; Chen-Izu, Ye; Clancy, Colleen E; Edwards, Andrew; Goldhaber, Joshua; Kaplan, Jack; Lingrel, Jerry B; Pavlovic, Davor; Philipson, Kenneth; Sipido, Karin R; Xie, Zi-Jian

    2015-01-01

    This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field. PMID:25772291

  16. Reduced Na+ uptake in the NaCl-hypersensitive sos1 mutant of Arabidopsis thaliana.

    PubMed Central

    Ding, L; Zhu, J K

    1997-01-01

    Sos1 is an Arabidopsis thaliana mutant with > 20 times higher sensitivity toward Na+ inhibition due to a defective high-affinity potassium-uptake system. We report here that sos1 accumulates less Na+ than the wild type in response to NaCl stress. The Na+ contents in sos1 seedlings exposed to 25 mM NaCl for 2 or more d are about 43% lower than those in the wild type. When assayed at 20 mM external NaCl, sos1 seedlings pretreated with low potassium have 32% lower Na+ uptake than the wild type. However, little difference in Na+ uptake could be measured when the seedlings were not pretreated with low potassium. Low-potassium treatment was shown to induce high-affinity potassium-uptake activity in Arabidopsis seedlings. No substantial difference in Na+ efflux between sos1 and the wild type was detected. The results show that the reduced Na+ accumulation in sos1 is due to a lower Na+ influx rate. Therefore, the sos1 mutation appears to disrupt low-affinity Na+ uptake in addition to its impairment of high-affinity K+ uptake. PMID:9085573

  17. Inelastic processes in Na+-Ne, Na+-Ar, Ne+-Na, and Ar+-Na collisions in the energy range 0.5-14 keV

    NASA Astrophysics Data System (ADS)

    Lomsadze, R. A.; Gochitashvili, M. R.; Kezerashvili, R. Ya.

    2015-12-01

    Absolute cross sections for charge-exchange, ionization, and excitation in Na+-Ne and Na+-Ar collisions were measured in the ion energy range 0.5 -10 keV using a refined version of a capacitor method and collision and optical spectroscopy methods simultaneously in the same experimental setup. Ionization cross sections for Ne+-Na and Ar+-Na collisions are measured at energies of 2 -14 keV using a crossed-beam spectroscopy method. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. For the charge-exchange process in Na+-Ar collisions two nonadiabatic regions are revealed and mechanisms responsible for these regions are explained. Structural peculiarity on the excitation function for the resonance lines of argon atoms in Na+-Ar collisions are observed and the possible mechanisms of this phenomenon are explored. The measured ionization cross sections for Na+-Ne and Ne+-Na collisions in conjunction with the Landau-Zener formula are used to determine the coupling matrix element and transition probability in a region of pseudocrossing of the potential curves.

  18. Regulation of Na+ fluxes in plants

    PubMed Central

    Maathuis, Frans J. M.; Ahmad, Izhar; Patishtan, Juan

    2014-01-01

    When exposed to salt, every plant takes up Na+ from the environment. Once in the symplast, Na+ is distributed within cells and between different tissues and organs. There it can help to lower the cellular water potential but also exert potentially toxic effects. Control of Na+ fluxes is therefore crucial and indeed, research shows that the divergence between salt tolerant and salt sensitive plants is not due to a variation in transporter types but rather originates in the control of uptake and internal Na+ fluxes. A number of regulatory mechanisms has been identified based on signaling of Ca2+, cyclic nucleotides, reactive oxygen species, hormones, or on transcriptional and post translational changes of gene and protein expression. This review will give an overview of intra- and intercellular movement of Na+ in plants and will summarize our current ideas of how these fluxes are controlled and regulated in the early stages of salt stress. PMID:25278946

  19. High NA Nicrostepper Final Optical Design Report

    SciTech Connect

    Hudyma, R

    1999-09-24

    The development of a new EUV high NA small-field exposure tool has been proposed for obtaining mask defect printability data in a timeframe several years before beta-tools are available. The imaging system for this new Micro-Exposure Tool (MET), would have a numerical aperture (NA) of about 0.3, similar to the NA for a beta-tool, but substantially larger than the 0.10 NA for the Engineering Test Stand (ETS) and 0.088 NA for the existing 10x Microstepper. This memorandum discusses the development and summarizes the performance of the camera for the MET and includes a listing of the design prescription, detailed analysis of the distortion, and analysis demonstrating the capability to resolution 30 nm features under the conditions of partially coherent illumination.

  20. Negative electrodes for Na-ion batteries.

    PubMed

    Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

    2014-08-01

    Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

  1. Na-doped optical Germanium bulk crystals

    NASA Astrophysics Data System (ADS)

    Pekar, G. S.; Singaevsky, A. F.

    2012-09-01

    In an effort to develop a material for infrared (IR) optics with improved parameters, bulk crystals of optical germanium doped with Na have been first grown and studied. Single-crystalline and coarse-crystalline Ge:Na boules of different shapes and dimensions, up to 10 kg by weight, have been grown. Sodium was incorporated into the Ge crystal during the crystal growing from the melt. Despite the fact that Na contamination in the source material was not strictly controlled, the density of Na in the grown crystals determined by the neutron activation analysis as well as by the glow discharge mass spectrometry did not exceed 1015 cm-3. Just this value may be supposed to be close to the solubility limit of Na incorporated in Ge in the course of bulk crystal growth. A first demonstration of donor behavior of Na in bulk Ge crystals is made by means of a thermoelectric type of testing. An interstitial location of Na impurity has been verified by experiments on donor drift in the dc electric field. The crystals are grown with free electron density in the range from 5ṡ1013 to 4ṡ1014 cm-3 which is optimal for using Ge crystals as an optical material for fabricating passive elements of the IR technique. A comparison between the properties of Ge:Na crystals and Ge crystals doped with Sb, a conventional impurity in optical germanium, grown under the same technological conditions and from the same intrinsic Ge as a source material, revealed a number of advantages of Ge:Na crystals; among them, the higher transparency in the IR region, smaller radiation scattering and higher regular optical transmission, lower dislocation density, more uniform distribution of electrical and optical characteristics over the crystal volume, the identity of optical parameters in the single-crystalline, and coarse-crystalline boules. No degradation of optical elements fabricated from Ge:Na crystals was detected in the course of their commercial application, starting from 1998.

  2. Polarization dependence of Na/emph>+Na/emph> associative ionization revisited

    NASA Astrophysics Data System (ADS)

    Meijer, H. A. J.; Meulen, H. P. V. D.; Morgenstern, R.; Hertel, I. V.; Meyer, E.; Schmidt, H.; Witte, R.

    1986-02-01

    The dependence of the associative ionization process Na 3 2P3/2+Na 3 2P3/2-->Na2 ++e- on the polarization of the laser light used for Na excitation was independently investigated in Utrecht and Berlin. The purpose of this paper is to clarify discrepancies between earlier experimental results of Kircz, Morgenstern, and Nienhuis, on one hand, and Rothe, Theyunni, Reck, and Tung on the other hand. The new results confirm in general the data of Kircz, Morgenstern, and Nienhuis, and also indicate a dependence of the anisotropy ratios on the relative velocity of the interacting Na* atoms.

  3. The NA62 RICH detector

    SciTech Connect

    Cassese, A.

    2011-07-01

    The NA62 experiment is designed to measure the very rare kaon decay K{sup +} {yields} {pi}{sup +} at the CERN SPS with a 10% accuracy. The Standard Model prediction for the Branching Ratio is (8.5 {+-} 0.7) x 10{sup -11}. One of the challenging aspect of the experiment is the suppression of the K{sup +} {yields} {mu}{sup +} v{sub {mu}} background at the 10{sup -12} level. To satisfy this requirement a Ring Imaging Cherenkov Detector (RICH), able to separate {pi}{sup {+-}} from {mu}{sup {+-}} in the momentum range between 15 and 35 GeV/c, with a {mu}, rejection factor better than 10{sup -2}, is needed. The RICH must also have a time resolution of about 100 ps to disentangle accidental time associations of beam particles with pions. The RICH will have a very long focal length (17 m) and will be filled with Ne gas at atmospheric pressure. Two test beams were held at CERN in 2007 and 2009 with a RICH prototype. The results of the two test beams will be presented: the {mu}, mis-identification probability is found to be about 0.7% and the time resolution better than 100 ps in the whole momentum range. (authors)

  4. Na-site substitution effects on the thermoelectric properties of NaCo2O4

    NASA Astrophysics Data System (ADS)

    Kawata, T.; Iguchi, Y.; Itoh, T.; Takahata, K.; Terasaki, I.

    1999-10-01

    The resistivity and thermopower of Na1+xCo2O4 and Na1.1-xCaxCo2O4 are measured and analyzed. In Na1+xCo2O4, whereas the resistivity increases with x, the thermopower is nearly independent of x. This suggests that the excess Na is unlikely to supply carriers, and decreases effective conduction paths in the sample. In Na1.1-xCaxCo2O4, the resistivity and the thermopower increase with x, and the Ca2+ substitution for Na+ reduces the majority carriers in NaCo2O4. This means that they are holes, which is consistent with the positive sign of the thermopower. Strong correlation in this compound is evidenced by the peculiar temperature dependence of the resistivity.

  5. Extracellular Na+ levels regulate formation and activity of the NaX/alpha1-Na+/K+-ATPase complex in neuronal cells

    PubMed Central

    Berret, Emmanuelle; Smith, Pascal Y.; Henry, Mélaine; Soulet, Denis; Hébert, Sébastien S.; Toth, Katalin; Mouginot, Didier; Drolet, Guy

    2014-01-01

    MnPO neurons play a critical role in hydromineral homeostasis regulation by acting as sensors of extracellular sodium concentration ([Na+]out). The mechanism underlying Na+-sensing involves Na+-flow through the NaX channel, directly regulated by the Na+/K+-ATPase α1-isoform which controls Na+-influx by modulating channel permeability. Together, these two partners form a complex involved in the regulation of intracellular sodium ([Na+]in). Here we aim to determine whether environmental changes in Na+ could actively modulate the NaX/Na+/K+-ATPase complex activity. We investigated the complex activity using patch-clamp recordings from rat MnPO neurons and Neuro2a cells. When the rats were fed with a high-salt-diet, or the [Na+] in the culture medium was increased, the activity of the complex was up-regulated. In contrast, drop in environmental [Na+] decreased the activity of the complex. Interestingly under hypernatremic condition, the colocalization rate and protein level of both partners were up-regulated. Under hyponatremic condition, only NaX protein expression was increased and the level of NaX/Na+/K+-ATPase remained unaltered. This unbalance between NaX and Na+/K+-ATPase pump proportion would induce a bigger portion of Na+/K+-ATPase-control-free NaX channel. Thus, we suggest that hypernatremic environment increases NaX/Na+/K+-ATPase α1-isoform activity by increasing the number of both partners and their colocalization rate, whereas hyponatremic environment down-regulates complex activity via a decrease in the relative number of NaX channels controlled by the pump. PMID:25538563

  6. Gasotransmitters: novel regulators of epithelial na(+) transport?

    PubMed

    Althaus, Mike

    2012-01-01

    The vectorial transport of Na(+) across epithelia is crucial for the maintenance of Na(+) and water homeostasis in organs such as the kidneys, lung, or intestine. Dysregulated Na(+) transport processes are associated with various human diseases such as hypertension, the salt-wasting syndrome pseudohypoaldosteronism type 1, pulmonary edema, cystic fibrosis, or intestinal disorders, which indicate that a precise regulation of epithelial Na(+) transport is essential. Novel regulatory signaling molecules are gasotransmitters. There are currently three known gasotransmitters: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H(2)S). These molecules are endogenously produced in mammalian cells by specific enzymes and have been shown to regulate various physiological processes. There is a growing body of evidence which indicates that gasotransmitters may also regulate Na(+) transport across epithelia. This review will summarize the available data concerning NO, CO, and H(2)S dependent regulation of epithelial Na(+) transport processes and will discuss whether or not these mediators can be considered as true physiological regulators of epithelial Na(+) transport biology.

  7. Myocardial Na,K-ATPase: Clinical aspects

    PubMed Central

    Kjeldsen, Keld

    2003-01-01

    The specific binding of digitalis glycosides to Na,K-ATPase is used as a tool for Na,K-ATPase quantification with high accuracy and precision. In myocardial biopsies from patients with heart failure, total Na,K-ATPase concentration is decreased by around 40%; a correlation exists between a decrease in heart function and a decrease in Na,K-ATPase concentration. During digitalization, around 30% of remaining pumps are occupied by digoxin. Myocardial Na,K-ATPase is also influenced by other drugs used for the treatment of heart failure. Thus, potassium loss during diuretic therapy has been found to reduce myocardial Na,K-ATPase, whereas angiotensin-converting enzyme inhibitors may stimulate Na,K pump activity. Furthermore, hyperaldosteronism induced by heart failure has been found to decrease Na,K-ATPase activity. Accordingly, treatment with the aldosterone antagonist, spironolactone, may also influence Na,K-ATPase activity. The importance of Na,K pump modulation with heart disease, inhibition in digitalization and other effects of medication should be considered in the context of sodium, potassium and calcium regulation. It is recommended that digoxin be administered to heart failure patients who, after institution of mortality-reducing therapy, still have heart failure symptoms, and that the therapy be continued if symptoms are revealed or reduced. Digitalis glycosides are the only safe inotropic drugs for oral use that improve hemodynamics in heart failure. An important aspect of myocardial Na,K pump affection in heart disease is its influence on extracellular potassium (Ke) homeostasis. Two important aspects should be considered: potassium handling among myocytes, and effects of potassium entering the extracellular space of the heart via the bloodstream. It should be noted that both of these aspects of Ke homeostasis are affected by regulatory aspects, eg, regulation of the Na,K pump by physiological and pathophysiological conditions, as well as by medical

  8. Characteristics and pharmacological regulation of epithelial Na+ channel (ENaC) and epithelial Na+ transport.

    PubMed

    Marunaka, Yoshinori

    2014-01-01

    Epithelial Na(+) transport participates in control of various body functions and conditions: e.g., homeostasis of body fluid content influencing blood pressure, control of amounts of fluids covering the apical surface of alveolar epithelial cells at appropriate levels for normal gas exchange, and prevention of bacterial/viral infection. Epithelial Na(+) transport via the transcellular pathway is mediated by the entry step of Na(+) across the apical membrane via Epithelial Na(+) Channel (ENaC) located at the apical membrane, and the extrusion step of Na(+) across the basolateral membrane via the Na(+),K(+)-ATPase located at the basolateral membrane. The rate-limiting step of the epithelial Na(+) transport via the transcellular pathway is generally recognized to be the entry step of Na(+) across the apical membrane via ENaC. Thus, up-/down-regulation of ENaC essentially participates in regulatory systems of blood pressure and normal gas exchange. Amount of ENaC-mediated Na(+) transport is determined by the number of ENaCs located at the apical membrane, activity (open probability) of individual ENaC located at the apical membrane, single channel conductance of ENaC located at the apical membrane, and driving force for the Na(+) entry via ENaCs across the apical membrane. In the present review article, I discuss the characteristics of ENaC and how these factors are regulated.

  9. Glutathionylation-Dependence of Na(+)-K(+)-Pump Currents Can Mimic Reduced Subsarcolemmal Na(+) Diffusion.

    PubMed

    Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J; Rasmussen, Helge H

    2016-03-01

    The existence of a subsarcolemmal space with restricted diffusion for Na(+) in cardiac myocytes has been inferred from a transient peak electrogenic Na(+)-K(+) pump current beyond steady state on reexposure of myocytes to K(+) after a period of exposure to K(+)-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na(+) that accumulated in the diffusion-restricted space during pump inhibition in K(+)-free extracellular solution. However, there are no known physical barriers that account for such restricted Na(+) diffusion, and we examined if changes of activity of the Na(+)-K(+) pump itself cause the transient peak current. Reexposure to K(+) reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na(+) concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K(+)-free pipette solution could not be reconciled with restricted subsarcolemmal Na(+) diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na(+)- and K(+) concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na(+)-K(+) pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na(+)-K(+) pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K(+)-induced peak Na(+)-K(+) pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K(+)-induced peak Na(+)-K(+) pump current reflects the effect

  10. Dependence of Na-K pump current on internal Na+ in mammalian cardiac myocytes.

    PubMed

    Mogul, D J; Singer, D H; Ten Eick, R E

    1990-08-01

    Na-K pump current (Ipump) is a function of the intracellular Na+ concentration [( Na+]i). We examined the quantitative relationship between Ipump and [Na+]i in isolated guinea pig ventricular myocytes under steady-state conditions. [Na+]i was controlled and "clamped" at several selected concentrations using wide-tipped pipette microelectrodes, and membrane current was measured using the whole cell patch voltage-clamp technique. Ipump generated at a holding potential of -40 mV was determined by measuring the change in steady-state holding current before and during exposure to dihydroouabain (1 mM); Ipump was measured at 11 levels of [Na+]i ranging from 0 to 80 mM (n = 63) with only one measurement per cell and normalized to cell capacitance to account for differences between myocytes in sarcolemmal surface area. Ipump exhibited a nonlinear dependence on [Na+]i; a Hill analysis of the relationship yielded a half-maximal [Na+]i for pump stimulation of 43.2 mM and a Hill coefficient of 1.53. An alternative analysis of the experimental data was performed assuming that occupation of three internal binding sites by Na+ is required for enzyme turnover. Regression analysis gave the best fit when only two different binding affinities (KD) are postulated. The values are KD1 = 1 mM, KD2 = KD3 = 29 mM. From the analysis using the latter model, the level of [Na+]i at which Ipump saturated closely approximated the theoretical saturation level calculated from published estimates of pump turnover rate and density. The maximal sensitivity of the Na-K pump to changes in [Na+]i occurs when internal [Na+] is within the range for the normal resting physiological level. PMID:2167023

  11. [Na+/H+- and Na+/Na+-countertransport in human, rabbit, and rat erythrocytes: evidence for the existence of two independent ion-transporting systems].

    PubMed

    Orlov, S N; Kuznetsov, S R; Kolosova, I A; Makarov, V L

    1994-05-01

    The activity and regulatory features of the Na+/H(+)- and Na+/Na(+)-exchange were studied in human, rabbit and rat red blood cells. No basal activity of the Na+/H(+)-exchange (the amyloride-inhibited component of the 22Na+ influx) in erythrocytes of these species was observed. The rate of 22Na+ influx increased rapidly when the experiments were carried out on acid-loaded cells in an alkaline (pH0 = 8.0) incubation medium (delta mu H(+)-induced Na+/H(+)-exchange). The ratio of delta mu H(+)-induced Na+/H(+)-exchange activities in human, rabbit and rat red blood cells was 1.0 : 1.1 : 2.3, respectively, whereas that of the Na+/Na(+)-exchange activities (the phloretin-inhibited component of the 22Na+ influx) in erythrocytes of these species was 1.0 : 4.6 : 0.2. The osmotic shrinkage of rat and rabbit erythrocytes led to the stimulation of the Na+/H(+)- (but not Na+/Na+) exchange. Amyloride (1 mM) inhibited the shrinkage-induced 22Na+ entry as well as the delta mu H(+)-induced 22Na+ entry--by 95 and 10-20%, respectively. Heat treatment (10 min, 49-51 degrees C), disturbing the membrane cytoskeleton suppressed both the shrinkage-induced activation and the delta mu H(+)-induced activation of the Na+/H(+)-exchange. The data obtained indicate that the both transport systems are mediated by two distinct transport carriers. It may be suggested that the delta mu H(+)-induced Na+/H(+)-exchange, on the one hand, and the shrinkage-induced Na+/H(+)-exchange, on the other, are mediated by two different Na+/H(+)-exchanger subtypes. PMID:8043690

  12. Anamorphic high-NA EUV lithography optics

    NASA Astrophysics Data System (ADS)

    Migura, Sascha; Kneer, Bernhard; Neumann, Jens Timo; Kaiser, Winfried; van Schoot, Jan

    2015-09-01

    EUV lithography (EUVL) for a limit resolution below 8 nm requires the numerical aperture (NA) of the projection optics to be larger than 0.50. For such a high-NA optics a configuration of 4x magnification, full field size of 26 x 33 mm² and 6'' mask is not feasible anymore. The increased chief ray angle and higher NA at reticle lead to non-acceptable mask shadowing effects. These shadowing effects can only be controlled by increasing the magnification, hence reducing the system productivity or demanding larger mask sizes. We demonstrate that the best compromise in imaging, productivity and field split is a so-called anamorphic magnification and a half field of 26 x 16.5 mm² but utilizing existing 6'' mask infrastructure. We discuss the optical solutions for such anamorphic high-NA EUVL.

  13. Searches for New Physics at NA62

    NASA Astrophysics Data System (ADS)

    Palladino, Vito

    2011-10-01

    We present the latest NA62 results in the search for physics beyond Standard Model (SM). NA62 aims to have indirect evidences of new physics, measuring rare K decays. NA62 phase I took place in 2007 when we collected data in order to measure the ratio RK = Ke2/Kμ2 (were Kl2 means K → lνl) at few per mill level. A brief experimental layout description will be followed by analysis strategy and preliminary results. The last part of present paper will be devoted to the description of NA62 phase II, which has the main goal of measuring the ultra-rare K -> π ^ + ν bar ν decay Branching Ratio.

  14. Nanosegregation in Na2C60

    SciTech Connect

    Klupp, G.; Kamaras, K.; Matus, P.; Kiss, L.F.; Kovats, E.; Pekker, S.; Nemes, N.M.; Quintavalle, D.; Janossy, A.

    2005-09-27

    There is continuous interest in the nature of alkali metal fullerides containing C{sub 60}{sup 4-} and C{sub 60}{sup 2-}, because these compounds are believed to be nonmagnetic Mott-Jahn-Teller insulators. This idea could be verified in the case of A4C60, but Na2C60 is more controversial. By comparing the results of infrared spectroscopy and X-ray diffraction, we found that Na2C60 is segregated into 3-10 nm large regions. The two main phases of the material are insulating C60 and metallic Na3C60. We found by neutron scattering that the diffusion of sodium ions becomes faster on heating. Above 470 K Na2C60 is homogeneous and we show IR spectroscopic evidence of a Jahn-Teller distorted C{sub 60}{sup 2-} anion.

  15. Looking for a Job: Step by Step = Buscando Trabajo: Paso por Paso.

    ERIC Educational Resources Information Center

    Edwards, Patricia

    This bilingual document provides guidelines and learning activities to assist migrant workers in looking for a job. The document covers the following areas: (1) a checklist providing an overview of job search skills; (2) developing a fact sheet of personal information; (3) listing good work qualities; (4) identifying references and securing…

  16. Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C

    SciTech Connect

    Carroll, S A; Craig, L; Wolery, T J

    2004-10-20

    We conducted reversed deliquescence experiments in saturated NaCl-NaNO{sub 3}-H{sub 2}O, KNO{sub 3}-NaNO{sub 3}-H{sub 2}O, and NaCl-KNO{sub 3}-H{sub 2}O systems from 90 to 120 C as a function of relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Discrepancy between model prediction and experimental code can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25 C models for Cl-NO{sub 3} and K-NO{sub 3} ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the non-ideal behavior of these highly concentrated solutions.

  17. Elastic Coulomb breakup of 34Na

    NASA Astrophysics Data System (ADS)

    Singh, G.; Shubhchintak, Chatterjee, R.

    2016-08-01

    Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our

  18. HCO3(-)-coupled Na+ influx is a major determinant of Na+ turnover and Na+/K+ pump activity in rat hepatocytes

    SciTech Connect

    Fitz, J.G.; Lidofsky, S.D.; Weisiger, R.A.; Xie, M.H.; Cochran, M.; Grotmol, T.; Scharschmidt, B.F. )

    1991-05-01

    Recent studies in hepatocytes indicate that Na(+)-coupled HCO3- transport contributes importantly to regulation of intracellular pH and membrane HCO3- transport. However, the direction of net coupled Na+ and HCO3- movement and the effect of HCO3- on Na+ turnover and Na+/K+ pump activity are not known. In these studies, the effect of HCO3- on Na+ influx and turnover were measured in primary rat hepatocyte cultures with 22Na+, and (Na+)i was measured in single hepatocytes using the Na(+)-sensitive fluorochrome SBFI. Na+/K+ pump activity was measured in intact perfused rat liver and hepatocyte monolayers as Na(+)-dependent or ouabain-suppressible 86Rb uptake, and was measured in single hepatocytes as the effect of transient pump inhibition by removal of extracellular K+ on membrane potential difference (PD) and (Na+)i. In hepatocyte monolayers, HCO3- increased 22Na+ entry and turnover rates by 50-65%, without measurably altering 22Na+ pool size or cell volume, and HCO3- also increased Na+/K+ pump activity by 70%. In single cells, exposure to HCO3- produced an abrupt and sustained rise in (Na+)i from approximately 8 to 12 mM. Na+/K+ pump activity assessed in single cells by PD excursions during transient K+ removal increased congruent to 2.5-fold in the presence of HCO3-, and the rise in (Na+)i produced by inhibition of the Na+/K+ pump was similarly increased congruent to 2.5-fold in the presence of HCO3-. In intact perfused rat liver, HCO3- increased both Na+/K+ pump activity and O2 consumption. These findings indicate that, in hepatocytes, net coupled Na+ and HCO3- movement is inward and represents a major determinant of Na+ influx and Na+/K+ pump activity. About half of hepatic Na+/K+ pump activity appears dedicated to recycling Na+ entering in conjunction with HCO3- to maintain (Na+)i within the physiologic range.

  19. Electrophysiological Determination of Submembrane Na(+) Concentration in Cardiac Myocytes.

    PubMed

    Hegyi, Bence; Bányász, Tamás; Shannon, Thomas R; Chen-Izu, Ye; Izu, Leighton T

    2016-09-20

    In the heart, Na(+) is a key modulator of the action potential, Ca(2+) homeostasis, energetics, and contractility. Because Na(+) currents and cotransport fluxes depend on the Na(+) concentration in the submembrane region, it is necessary to accurately estimate the submembrane Na(+) concentration ([Na(+)]sm). Current methods using Na(+)-sensitive fluorescent indicators or Na(+) -sensitive electrodes cannot measure [Na(+)]sm. However, electrophysiology methods are ideal for measuring [Na(+)]sm. In this article, we develop patch-clamp protocols and experimental conditions to determine the upper bound of [Na(+)]sm at the peak of action potential and its lower bound at the resting state. During the cardiac cycle, the value of [Na(+)]sm is constrained within these bounds. We conducted experiments in rabbit ventricular myocytes at body temperature and found that 1) at a low pacing frequency of 0.5 Hz, the upper and lower bounds converge at 9 mM, constraining the [Na(+)]sm value to ∼9 mM; 2) at 2 Hz pacing frequency, [Na(+)]sm is bounded between 9 mM at resting state and 11.5 mM; and 3) the cells can maintain [Na(+)]sm to the above values, despite changes in the pipette Na(+) concentration, showing autoregulation of Na(+) in beating cardiomyocytes. PMID:27653489

  20. Interaction of NaCl(g) and HCl(g) with condensed NA2SO4

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.; Miller, R. A.

    1977-01-01

    The interaction of Na2SO4(l) with NaCl(g), HCl(g) and H2O(g) was studied in atmospheric pressure flowing air and oxygen at Na2SO4(l) temperatures of 900 and 1000 C. Thermomicrogravimetric and high pressure mass spectrometric sampling techniques were used. Experimental results establish that previously reported enhanced rates of weight loss of Na2SO4(l) in the presence of NaCl(g) are due to the reaction: Na2SO4(c) + 2HCl(g) = 2NaCl(g) + SO2(g) + H2O(g) + 1/2O2(g) being driven to the right in flowing gas systems. The HCl(g) is the product of hydrolysis of NaCl caused by small but significant amounts of H2O(g) present in the system. Thermochemical calculations are used to show that even with sub-ppm levels of H2O(g) present, significant quantities of HCl(g) are produced.

  1. Direct Measurement of ^21Na+α Stellar Reaction

    NASA Astrophysics Data System (ADS)

    Binh Dam, Nguyen; Yamaguchi, H.; Wakabayashi, Y.; Hayakawa, S.; Hashimoto, T.; Kahl, D.; Kubono, S.; Le, H. K.; Nguyen, T. T.; Iwasa, N.; Kume, N.; Kato, S.; Teranishi, T.

    2009-10-01

    Nucleosynthesis of ^22Na is an interesting subject because of possible γ-ray observation and isotopic anomalies in presolar grain. ^22Na would have been mainly produced in the NeNa cycle. At high temperature conditions, ^21Na(α,p)^24Mg reaction could play a significant role to make flow from the NeNa cycle to the next MgAl cycle and beyond. Clearly, the ^21Na(α,p)^24Mg stellar reaction would bypass ^22Na, resulting in reduction of ^22Na production, therefore, it is strongly coupled to the Ne-E problem. It could be also important to understand the early stage of the rp-process. Experiment was performed using a 39 MeV ^21Na radioactive beam obtained by the CNS Radio Isotope Beam separator CRIB of the University of Tokyo. Both protons and alphas were measured from α+^21Na scattering with a thick ^4He gas target.

  2. Functional coupling of renal K+ and Na+ handling causes high blood pressure in Na+ replete mice

    PubMed Central

    Vitzthum, Helga; Seniuk, Anika; Schulte, Laura Helene; Müller, Maxie Luise; Hetz, Hannah; Ehmke, Heimo

    2014-01-01

    A network of kinases, including WNKs, SPAK and Sgk1, is critical for the independent regulation of K+ and Na+ transport in the distal nephron. Angiotensin II is thought to act as a key hormone in orchestrating these kinases to switch from K+ secretion during hyperkalaemia to Na+ reabsorption during intravascular volume depletion, thus keeping disturbances in electrolyte and blood pressure homeostasis at a minimum. It remains unclear, however, how K+ and Na+ transport are regulated during a high Na+ intake, which is associated with suppressed angiotensin II levels and a high distal tubular Na+ load. We therefore investigated the integrated blood pressure, renal, hormonal and gene and protein expression responses to large changes of K+ intake in Na+ replete mice. Both low and high K+ intake increased blood pressure and caused Na+ retention. Low K+ intake was accompanied by an upregulation of the sodium-chloride cotransporter (NCC) and its activating kinase SPAK, and inhibition of NCC normalized blood pressure. Renal responses were unaffected by angiotensin AT1 receptor antagonism, indicating that low K+ intake activates the distal nephron by an angiotensin-independent mode of action. High K+ intake was associated with elevated plasma aldosterone concentrations and an upregulation of the epithelial sodium channel (ENaC) and its activating kinase Sgk1. Surprisingly, high K+ intake increased blood pressure even during ENaC or mineralocorticoid receptor antagonism, suggesting the contribution of aldosterone-independent mechanisms. These findings show that in a Na+ replete state, changes in K+ intake induce specific molecular and functional adaptations in the distal nephron that cause a functional coupling of renal K+ and Na+ handling, resulting in Na+ retention and high blood pressure when K+ intake is either restricted or excessively increased. PMID:24396058

  3. NaCd excimer emission bands

    NASA Astrophysics Data System (ADS)

    Pichler, G.; Veža, D.; Fijan, D.

    1988-06-01

    The analysis of the visible spectrum of a high pressure sodium lamp filled with sodium, cadium and xenon revealed the existence of NaCd excimer spectral features. These are four red satellite bands at 691, 697, 709 and 726.5 nm and diffuse bands peaking at 479.1 and 484.3 nm. Both spectral phenomena are related to those found earlier for the NaHg system. An interpretation of the red satellite bands origin is given in terms of a qualitative model for the four lowest potential curves of the NaCd excimer. In this model the essential feature is the avoided crossing between B 2∑ 1/2 and A 2∏ 1/2 electronic states, which causes a complex structure of the satellite bands in the very far red wing of the sodium D lines broadened by cadmium.

  4. Targeting voltage gated sodium channels NaV1.7, Na V1.8, and Na V1.9 for treatment of pathological cough.

    PubMed

    Muroi, Yukiko; Undem, Bradley J

    2014-02-01

    Recent advances in our understanding of voltage-gated sodium channels (NaVs) lead to the rational hypothesis that drugs capable of selective blockade of NaV subtypes may be a safe and effective strategy for the treatment of unwanted cough. Among the nine NaV subtypes (NaV1.1-NaV1.9), the afferent nerves involved in initiating cough, in common with nociceptive neurons in the somatosensory system, express mainly NaV1.7, NaV1.8, and NaV1.9. Although knowledge about the effect of selectively blocking these channels on the cough reflex is limited, their biophysical properties indicate that each may contribute to the hypertussive and allotussive state that typifies subacute and chronic nonproductive cough.

  5. Concentration dependence of Li+/Na+ diffusion in manganese hexacyanoferrates

    NASA Astrophysics Data System (ADS)

    Takachi, Masamitsu; Fukuzumi, Yuya; Moritomo, Yutaka

    2016-06-01

    Manganese hexacyanoferrates (Mn-HCFs) with a jungle-gym-type structure are promising cathode materials for Li+/Na+ secondary batteries (LIBs/SIBs). Here, we investigated the diffusion constants D Li/D Na of Li+/Na+ against the Li+/Na+ concentration x Na/x Li and temperature (T) of A 1.32Mn[Fe(CN)6]0.833.6H2O (A = Li and Na). We evaluated the activation energy E\\text{a}\\text{Li}/E\\text{a}\\text{Na} of D Li/D Na against x Na/x Li. We found that E\\text{a}\\text{Na} steeply increases with x Na from 0.41 eV at x Na = 0.69 to 0.7 eV at 1.1. The increase in E\\text{a}\\text{Na} is ascribed to the occupancy effect of the Na+ site. The increase in E\\text{a}\\text{Li} is suppressed, probably because the number of Li+ sites is three times that of Na+ sites.

  6. Crystal structure of a Na+-bound Na+,K+-ATPase preceding the E1P state.

    PubMed

    Kanai, Ryuta; Ogawa, Haruo; Vilsen, Bente; Cornelius, Flemming; Toyoshima, Chikashi

    2013-10-10

    Na(+),K(+)-ATPase pumps three Na(+) ions out of cells in exchange for two K(+) taken up from the extracellular medium per ATP molecule hydrolysed, thereby establishing Na(+) and K(+) gradients across the membrane in all animal cells. These ion gradients are used in many fundamental processes, notably excitation of nerve cells. Here we describe 2.8 Å-resolution crystal structures of this ATPase from pig kidney with bound Na(+), ADP and aluminium fluoride, a stable phosphate analogue, with and without oligomycin that promotes Na(+) occlusion. These crystal structures represent a transition state preceding the phosphorylated intermediate (E1P) in which three Na(+) ions are occluded. Details of the Na(+)-binding sites show how this ATPase functions as a Na(+)-specific pump, rejecting K(+) and Ca(2+), even though its affinity for Na(+) is low (millimolar dissociation constant). A mechanism for sequential, cooperative Na(+) binding can now be formulated in atomic detail. PMID:24089211

  7. Na+/K+-ATPase: Activity and inhibition

    NASA Astrophysics Data System (ADS)

    Čolović, M.; Krstić, D.; Krinulović, K.; Momić, T.; Savić, J.; Vujačić, A.; Vasić, V.

    2009-09-01

    The aim of the study was to give an overview of the mechanism of inhibition of Na+/K+-ATPase activity induced by some specific and non specific inhibitors. For this purpose, the effects of some ouabain like compounds (digoxin, gitoxin), noble metals complexes ([PtCl2DMSO2], [AuCl4]-, [PdCl4]2-, [PdCl(dien)]+, [PdCl(Me4dien)]+), transition metal ions (Cu2+, Zn2+, Fe2+, Co2+), and heavy metal ions (Hg2+, Pb2+, Cd2+) on the activity of Na+/K+-ATPase from rat synaptic plasma membranes (SPM), porcine cerebral cortex and human erythrocytes were discussed.

  8. Na+ Inhibits the Epithelial Na+ Channel by Binding to a Site in an Extracellular Acidic Cleft*

    PubMed Central

    Kashlan, Ossama B.; Blobner, Brandon M.; Zuzek, Zachary; Tolino, Michael; Kleyman, Thomas R.

    2015-01-01

    The epithelial Na+ channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. These channels have large extracellular regions that are thought to interact with environmental cues, such as Na+, Cl−, protons, proteases, and shear stress, which modulate gating behavior. We sought to determine the molecular mechanism by which ENaC senses high external Na+ concentrations, resulting in an inhibition of channel activity. Both our structural model of an ENaC α subunit and the resolved structure of an acid-sensing ion channel (ASIC1) have conserved acidic pockets in the periphery of the extracellular region of the channel. We hypothesized that these acidic pockets host inhibitory allosteric Na+ binding sites. Through site-directed mutagenesis targeting the acidic pocket, we modified the inhibitory response to external Na+. Mutations at selected sites altered the cation inhibitory preference to favor Li+ or K+ rather than Na+. Channel activity was reduced in response to restraining movement within this region by cross-linking structures across the acidic pocket. Our results suggest that residues within the acidic pocket form an allosteric effector binding site for Na+. Our study supports the hypothesis that an acidic cleft is a key ligand binding locus for ENaC and perhaps other members of the ENaC/degenerin family. PMID:25389295

  9. Study on Na layer response to geomagnetic activities based on Odin/OSIRIS Na density data

    NASA Astrophysics Data System (ADS)

    Tsuda, Takuo; Nakamura, Takuji; Hedin, Jonas; Gumbel, Jorg; Hosokawa, Keisuke; Ejiri, Mitsumu K.; Nishiyama, Takanori; Takahashi, Toru

    2016-07-01

    The Na layer is normally distributed from 80 to 110 km, and the height range is corresponding to the ionospheric D and E region. In the polar region, the energetic particles precipitating from the magnetosphere can often penetrate into the E region and even into the D region. Thus, the influence of the energetic particles to the Na layer is one of interests in the aspect of the atmospheric composition change accompanied with the auroral activity. There are several previous studies in this issue. For example, recently, we have reported an initial result on a clear relationship between the electron density increase (due to the energetic particles) and the Na density decrease from observational data sets obtained by Na lidar, EISCAT VHF radar, and optical instruments at Tromsoe, Norway on 24-25 January 2012. However, all of the previous studies had been carried out based on case studies by ground-based lidar observations. In this study, we have performed, for the first time, statistical analysis using Na density data from 2004 to 2009 obtained with the Optical Spectrograph and InfraRed Imager System (OSIRIS) onboard Odin satellite. In the presentation, we will show relationship between the Na density and geomagnetic activities, and its latitudinal variation. Based on these results, the Na layer response to the energetic particles will be discussed.

  10. Na+ inhibits the epithelial Na+ channel by binding to a site in an extracellular acidic cleft.

    PubMed

    Kashlan, Ossama B; Blobner, Brandon M; Zuzek, Zachary; Tolino, Michael; Kleyman, Thomas R

    2015-01-01

    The epithelial Na(+) channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. These channels have large extracellular regions that are thought to interact with environmental cues, such as Na(+), Cl(-), protons, proteases, and shear stress, which modulate gating behavior. We sought to determine the molecular mechanism by which ENaC senses high external Na(+) concentrations, resulting in an inhibition of channel activity. Both our structural model of an ENaC α subunit and the resolved structure of an acid-sensing ion channel (ASIC1) have conserved acidic pockets in the periphery of the extracellular region of the channel. We hypothesized that these acidic pockets host inhibitory allosteric Na(+) binding sites. Through site-directed mutagenesis targeting the acidic pocket, we modified the inhibitory response to external Na(+). Mutations at selected sites altered the cation inhibitory preference to favor Li(+) or K(+) rather than Na(+). Channel activity was reduced in response to restraining movement within this region by cross-linking structures across the acidic pocket. Our results suggest that residues within the acidic pocket form an allosteric effector binding site for Na(+). Our study supports the hypothesis that an acidic cleft is a key ligand binding locus for ENaC and perhaps other members of the ENaC/degenerin family. PMID:25389295

  11. Role of the Na(+)-translocating NADH:quinone oxidoreductase in voltage generation and Na(+) extrusion in Vibrio cholerae.

    PubMed

    Vorburger, Thomas; Nedielkov, Ruslan; Brosig, Alexander; Bok, Eva; Schunke, Emina; Steffen, Wojtek; Mayer, Sonja; Götz, Friedrich; Möller, Heiko M; Steuber, Julia

    2016-04-01

    For Vibrio cholerae, the coordinated import and export of Na(+) is crucial for adaptation to habitats with different osmolarities. We investigated the Na(+)-extruding branch of the sodium cycle in this human pathogen by in vivo (23)Na-NMR spectroscopy. The Na(+) extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR). In a V. cholerae deletion mutant devoid of the Na(+)-NQR encoding genes (nqrA-F), rates of respiratory Na(+) extrusion were decreased by a factor of four, but the cytoplasmic Na(+) concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (ΔΨ, inside negative) and did not grow under hypoosmotic conditions at pH8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na(+)/H(+) antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na(+) concentrations, the Na(+)-NQR is crucial for generation of a transmembrane voltage to drive the import of H(+) by electrogenic Na(+)/H(+) antiporters. Our study provides the basis to understand the role of the Na(+)-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na(+) pump for respiration. PMID:26721205

  12. Mechanisms contributing to the cardiac inotropic effect of Na pump inhibition and reduction of extracellular Na

    PubMed Central

    1987-01-01

    Reduction of the transsarcolemmal [Na] gradient in rabbit cardiac muscle leads to an increase in the force of contraction. This has frequently been attributed to alteration of Ca movements via the sarcolemmal Na/Ca exchange system. However, the specific mechanisms that mediate the increased force at individual contractions have not been clearly established. In the present study, the [Na] gradient was decreased by reduction of extracellular [Na] or inhibition of the Na pump by either the cardioactive steroid acetylstrophanthidin or by reduction of extracellular [K]. Contractile performance and changes in extracellular Ca (sensed by double-barreled Ca-selective microelectrodes) were studied in order to elucidate the underlying basis for the increase in force. In the presence of agents that inhibit sarcoplasmic reticulum (SR) function (10 mM caffeine, 100-500 nM ryanodine), reduction of the [Na] gradient produced increases in contractile force similar to that observed in the absence of caffeine or ryanodine. It is concluded that an intact, functioning SR is not required for the inotropic effect of [Na] gradient reduction (at least in rabbit ventricle). However, this does not exclude a possible contribution of enhanced SR Ca release in the inotropic response to [Na] gradient reduction in the absence of caffeine or ryanodine. Acetylstrophanthidin (3-5 microM) usually leads to an increase in the magnitude of extracellular Ca depletions associated with individual contractions. However, acetylstrophanthidin can also increase extracellular Ca accumulation during the contraction, especially at potentiated contractions. This extracellular Ca accumulation can be suppressed by ryanodine and it is suggested that this apparent enhancement of Ca efflux is secondary to an enhanced release of Ca from the SR. Under conditions where Ca efflux during contractions is minimized (after a rest interval in the presence of ryanodine), acetylstrophanthidin increased both the rate and the

  13. Laser trapping of {sup 21}Na atoms

    SciTech Connect

    Lu, Zheng-Tian

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  14. The solubility of Cr(OH){sub 3}(am) in concentrated NaOH and NaOH-NaNO{sub 3} solutions

    SciTech Connect

    Felmy, A.R.; Rai, D.; Fulton, R.W.

    1994-08-01

    Chromium is a major component of the Hanford waste tank sludges, and the presence of Cr in the sludges is a significant concern in the disposal of these sludges because Cr can interfere with the formation of waste glasses. One of the current pretreatment strategies for removing constituents that can interfere with glass formation, such as P and Cr, is to wash/dissolve the sludges in basic NaOH solutions. The solubility of Cr(OH){sub 3}(am) was measured in concentrated NaOH ranging in concentration from 0.1M to 6.0M and in NaOH-NaNO{sub 3} solutions with fixed NaOH concentration and variable NaNO{sub 3} concentration at room temperature (22--23 C). Equilibrium between solids and solutions was approached relatively slowly and required approximately 60--70 days before steady-state concentrations were reached. A thermodynamic model, based upon the Pitzer equations, was developed from the solubility data in NaOH, which includes only two aqueous Cr species (Cr(OH){sub 4}{sup {minus}} and NaCr(OH){sub 4}(aq)) and ion-interaction parameters for Na{sup +} with Cr(OH){sub 4}{sup {minus}}. This model was then tested in the mixed NaOH-NaNO{sub 3} solutions and found to be reliable.

  15. 24Mg( p, α)21Na reaction study for spectroscopy of 21Na

    NASA Astrophysics Data System (ADS)

    Cha, S. M.; Chae, K. Y.; Kim, A.; Lee, E. J.; Ahn, S.; Bardayan, D. W.; Chipps, K. A.; Cizewski, J. A.; Howard, M. E.; Manning, B.; O'Malley, P. D.; Ratkiewicz, A.; Strauss, S.; Kozub, R. L.; Matos, M.; Pain, S. D.; Pittman, S. T.; Smith, M. S.; Peters, W. A.

    2015-10-01

    The 24Mg( p, α)21Na reaction was measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to better constrain the spins and parities of the energy levels in 21Na for the astrophysically important 17F( α, p)20Ne reaction rate calculation. 31-MeV proton beams from the 25-MV tandem accelerator and enriched 24Mg solid targets were used. Recoiling 4He particles from the 24Mg( p, α)21Na reaction were detected by a highly segmented silicon detector array which measured the yields of 4He particles over a range of angles simultaneously. A new level at 6661 ± 5 keV was observed in the present work. The extracted angular distributions for the first four levels of 21Na and the results from distorted wave Born approximation (DWBA) calculations were compared to verify and extract the angular momentum transfer.

  16. Inhibition of Na(+)-independent H+ pump by Na(+)-induced changes in cell Ca2+

    PubMed Central

    1991-01-01

    Apical membrane H+ extrusion in the renal outer medullary collecting duct, inner stripe, is mediated by a Na(+)-independent H+ pump. To examine the regulation of this transporter, cell pH and cell Ca2+ were measured microfluorometrically in in vitro perfused tubules using 2',7'- bis(carboxyethyl)-5(6)-carboxyfluorescein and fura-2, respectively. Apical membrane H+ pump activity, assayed as cell pH recovery from a series of acid loads (NH3/NH+4 prepulse) in the total absence of ambient Na+, initially occurred at a slow rate (0.06 +/- 0.02 pH units/min), which was not sufficient to account for physiologic rates of H+ extrusion. Over 15-20 min after the initial acid load, the rate of Na(+)-independent cell pH recovery increased to 0.63 +/- 0.09 pH units/min, associated with a steady-state cell pH greater than the initial pre-acid load cell pH. This pattern suggested an initial suppression followed by a delayed activation of the apical membrane H+ pump. Replacement of peritubular Na+ with choline or N-methyl-D- glucosamine resulted in an initial spike increase in cell Ca2+ followed by a sustained increase in cell Ca2+. The initial rate of Na(+)- independent cell pH recovery could be increased by elimination of the Na+ removal-induced sustained cell Ca2+ elevation by: (a) performing studies in the presence of 135 mM peritubular Na+ (1 mM peritubular amiloride used to inhibit basolateral membrane Na+/H+ antiport); (b) clamping cell Ca2+ low with dimethyl-BAPTA, an intracellular Ca2+ chelating agent; or (c) removal of extracellular Ca2+. Cell acidification induced a spike increase in cell Ca2+. The late acceleration of Na(+)-independent cell pH recovery was independent of Na+ removal and of the method used to acidify the cell, but was eliminated by prevention of the cell Ca2+ spike and markedly delayed by the microfilament-disrupting agent, cytochalasin B. This study demonstrates that peritubular Na+ removal results in a sustained elevation in cell Ca2+, which inhibits

  17. A Selective Na(+) Aptamer Dissected by Sensitized Tb(3+) Luminescence.

    PubMed

    Zhou, Wenhu; Ding, Jinsong; Liu, Juewen

    2016-08-17

    A previous study of two RNA-cleaving DNAzymes, NaA43 and Ce13d, revealed the possibility of a common Na(+) aptamer motif. Because Na(+) binding to DNA is a fundamental biochemical problem, the interaction between Ce13d and Na(+) was studied in detail by using sensitized Tb(3+) luminescence spectroscopy. Na(+) displaces Tb(3+) from the DNAzyme, and thus quenches the emission from Tb(3+) . The overall requirement for Na(+) binding includes the hairpin and the highly conserved 16-nucleotide loop in the enzyme strand, along with a few unpaired nucleotides in the substrate. Mutation studies indicate good correlation between Na(+) binding and cleavage activity, thus suggesting a critical role of Na(+) binding for the enzyme activity. Ce13d displayed a Kd of ∼20 mm with Na(+) (other monovalent cations: 40-60 mm). The Kd values for other metal ions are mainly due to non-specific competition. With a single nucleotide mutation, the specific Na(+) binding was lost. Another mutant improved Kd to 8 mm with Na(+) . This study has demonstrated a Na(+) aptamer with important biological implications and analytical applications. It has also defined the structural requirements for Na(+) binding and produced an improved mutant. PMID:27238890

  18. Intracellular Na+ regulation of Na+ pump sites in cultured vascular smooth muscle cells

    SciTech Connect

    Allen, J.C.; Navran, S.S.; Seidel, C.L.; Dennison, D.K.; Amann, J.M.; Jemelka, S.K.

    1989-04-01

    Enzymatically dispersed cells from canine saphenous vein and femoral artery were grown in fetal calf serum and studied at day 0 (freshly dispersed) through confluence in primary culture. Intracellular Na levels (Nai), but not intracellular K (Ki), were increased after 24 h in culture and then decreased to a steady state by 4 days. Na+ pump site number (( /sup 3/H) ouabain binding) increased through day 3 and remained elevated. Nai was still elevated at 2 days when the Na+ pump site number began to increase. Total pump turnover (maximum ouabain-inhibited /sup 86/Rb uptake) reflected the increase in Na+ pump site number. These key events precede the observed increases in both protein production and cellular proliferation. If the same cells are maintained in defined medium, without fetal calf serum, Nai, Ki, and the number of (/sup 3/H)ouabain binding sites do not change with time. These data are consistent with the suggestion that the initial mitogenic response of vascular smooth muscle cells to fetal calf serum involves an increased Na+ influx, and a Nai accumulation, caused by low Na+ pump density. The synthesis of new pump sites effects a decrease in the accumulated Nai, which may be related to cell proliferation.

  19. Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

    NASA Technical Reports Server (NTRS)

    Cherng, Jing-Yih; Bennion, Douglas N.

    1987-01-01

    A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

  20. Final-state symmetry of Na 1s core-shell excitons in NaCl and NaF

    SciTech Connect

    Nagle, K.P.; Seidler, G.T.; Shirley, E.L.; Fister, T.T.; Bradley, J.A.; Brown, F.C.

    2009-08-13

    We report measurements of the Na 1s contribution to the nonresonant inelastic x-ray scattering (NRIXS) from NaCl and NaF. Prior x-ray absorption studies have observed two pre-edge excitons in both materials. The momentum-transfer dependence (q dependence) of the measured NRIXS cross section and of real-space full multiple scattering and Bethe-Salpeter calculations determine that the higher-energy core excitons are s type for each material. The lower-energy core excitons contribute at most weakly to the NRIXS signal and we propose that these may be surface core excitons, as have been observed in several other alkali halides. The analysis of the orbital angular momentum of these features leads to a discussion of the limited sensitivity of NRIXS measurements to d-type final states when investigating 1s initial states. In this case the s- and p-type final density of states can be characterized by measurements at a small number of momentum transfers. This is in contrast to the case of more complex initial states for which measurements at a large number of momentum transfers are needed to separate the rich admixture of accessible and contributing final-state symmetries.

  1. Final-state symmetry of Na 1s core-shell excitons in NaCl and NaF.

    SciTech Connect

    Nagle, K. P.; Seidler, G. T.; Shirley, E. L.; Fister, T. T.; Bradley, J. A.; Brown, F. C.; Materials Science Division; Univ. of Washington; NIST

    2009-01-01

    We report measurements of the Na 1s contribution to the nonresonant inelastic x-ray scattering (NRIXS) from NaCl and NaF. Prior x-ray absorption studies have observed two pre-edge excitons in both materials. The momentum-transfer dependence (q dependence) of the measured NRIXS cross section and of real-space full multiple scattering and Bethe-Salpeter calculations determine that the higher-energy core excitons are s type for each material. The lower-energy core excitons contribute at most weakly to the NRIXS signal and we propose that these may be surface core excitons, as have been observed in several other alkali halides. The analysis of the orbital angular momentum of these features leads to a discussion of the limited sensitivity of NRIXS measurements to d-type final states when investigating 1s initial states. In this case the s- and p-type final density of states can be characterized by measurements at a small number of momentum transfers. This is in contrast to the case of more complex initial states for which measurements at a large number of momentum transfers are needed to separate the rich admixture of accessible and contributing final-state symmetries.

  2. Rescue of Na+ affinity in aspartate 928 mutants of Na+,K+-ATPase by secondary mutation of glutamate 314.

    PubMed

    Holm, Rikke; Einholm, Anja P; Andersen, Jens P; Vilsen, Bente

    2015-04-10

    The Na(+),K(+)-ATPase binds Na(+) at three transport sites denoted I, II, and III, of which site III is Na(+)-specific and suggested to be the first occupied in the cooperative binding process activating phosphorylation from ATP. Here we demonstrate that the asparagine substitution of the aspartate associated with site III found in patients with rapid-onset dystonia parkinsonism or alternating hemiplegia of childhood causes a dramatic reduction of Na(+) affinity in the α1-, α2-, and α3-isoforms of Na(+),K(+)-ATPase, whereas other substitutions of this aspartate are much less disruptive. This is likely due to interference by the amide function of the asparagine side chain with Na(+)-coordinating residues in site III. Remarkably, the Na(+) affinity of site III aspartate to asparagine and alanine mutants is rescued by second-site mutation of a glutamate in the extracellular part of the fourth transmembrane helix, distant to site III. This gain-of-function mutation works without recovery of the lost cooperativity and selectivity of Na(+) binding and does not affect the E1-E2 conformational equilibrium or the maximum phosphorylation rate. Hence, the rescue of Na(+) affinity is likely intrinsic to the Na(+) binding pocket, and the underlying mechanism could be a tightening of Na(+) binding at Na(+) site II, possibly via movement of transmembrane helix four. The second-site mutation also improves Na(+),K(+) pump function in intact cells. Rescue of Na(+) affinity and Na(+) and K(+) transport by second-site mutation is unique in the history of Na(+),K(+)-ATPase and points to new possibilities for treatment of neurological patients carrying Na(+),K(+)-ATPase mutations.

  3. Cardiac Na Channels: Structure to Function.

    PubMed

    DeMarco, K R; Clancy, C E

    2016-01-01

    Heart rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. Opening of the primary cardiac voltage-gated sodium (NaV1.5) channel initiates cellular depolarization and the propagation of an electrical action potential that promotes coordinated contraction of the heart. The regularity of these contractile waves is critically important since it drives the primary function of the heart: to act as a pump that delivers blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. Perturbations to NaV1.5 may alter the structure, and hence the function, of the ion channel and are associated downstream with a wide variety of cardiac conduction pathologies, such as arrhythmias. PMID:27586288

  4. Optically pumped Na/sub 2/ laser

    SciTech Connect

    Kanorskii, S.I.; Kaslin, V.M.; Yakushev, O.F.

    1980-10-01

    A pulsed copper vapor laser emitting the 578.2 nm line was used as the pump source in achieving stimulated emission as a result of the electronic A/sup 1/..sigma../sup +//sub u/ to X/sup 1/..sigma../sup +//sub g/ transitions in the Na/sub 2/ molecule in the spectral range 0.765 to 0.804 ..mu... The average power of all the emission lines was 10 mW when the pulsed pump power was 150 W and the efficiency of conversion of the optical pump energy was about 3%. The pulse repetition frequency was 3.3 kHz. Violet diffuse radiation of the Na/sub 2/ molecules, generated by pumping with the copper vapor laser, was observed. The superradiance regime was found for some of the lines.

  5. Igneous origin for the NA in the cloud of Io

    NASA Astrophysics Data System (ADS)

    Johnson, M. L.; Burnett, D. S.

    1990-06-01

    Mixtures of sulfur and Na-bearing silicates were heated in evacuated silica glass capsules to temperatures between 600 C and 950 C. At or above 850 C, Na-silicate glass reacts with elemental S to form a (Na, K) sulfide. Mobilization of this phase may account for the presence of Na and K on the surface of Io, and hence in the material sputtered onto the Jovian magnetosphere.

  6. Sources of Na for the Io atmosphere

    NASA Technical Reports Server (NTRS)

    Burnett, D. S.; Ellis, Susan B.; Rice, A.; Epstein, S.

    1993-01-01

    The physics and geology of Io have been extensively studied, but there has been little discussion of the chemistry. Relatively little is known about Io chemistry, but there are constraints. Further, it will be a long time before improvements will result from direct observation, given the severe difficulties with the Galileo mission. Via laboratory simulation experiments, plausible thermochemical and photochemical processes which determine the nature and amounts of surface constituents of Io are explored. The well-known density of Io shows that the planet overall is rocky. Because the orbit of Io is well within the magnetosphere of Jupiter and because Io only has a thin, transient SO2 atmosphere, the surface is continually sputtered with magnetospheric ions. Complex processes ionize and accelerate the Io surface atoms to keV and MeV energies. Remarkably, only S, O, and Na ions were found by Voyager. Sputtering also produces an atomic cloud of Na and S (O not observable) with a trace of K. Both gaseous and solid SO2 are known from spectroscopic studies. A trace of H2S and possibly CO2 are present. Geologic features are interpreted in terms of elemental S, but there is no direct evidence for this constituent. We thus have a rocky planet which does not have rocks on the surface. Our general goal is to understand the cycling of Na, S, and O through the crust and atmosphere on present-day Io and to understand how Io evolved to this state. A specific objective was to determine the phases on the surface which are the source of the Na in the atmosphere of Io.

  7. Hybrid thermoelastic properties of NaCl

    NASA Astrophysics Data System (ADS)

    Wentzcovitch, R. M.; Marcondes, M. L.; Shukla, G.

    2015-12-01

    Despite the importance of thermoelastic properties of minerals in geophysics, their measurements at high pressures and temperatures are limited. Thus, ab initio calculations are an essential tool for predicting these properties at extreme conditions. Owing to the approximate description of the exchange-correlation energy and to approximations used in calculations of vibrational effects, these methods produce systematic deviations. Hybrid schemes combining experimental data and theoretical results have emerged as a way to reconcile available information and offer more reliable predictions at experimentally inaccessible thermodynamics conditions. Here we introduce a hybrid scheme to reconcile calculated and measured elastic coefficients and apply it to rock-salt-type NaCl, a challenging material to describe by ab initio and an important mineral in the context of oil/gas exploration. The approach is predictive within the temperature range of validity of the quasiharmonic approximation and results are used to generate velocities of NaCl at desirable geological conditions. [1] Marcondes, M. L. & Wentzcovitch, R.M. (2015). Hybrid ab-initio/experimental thermal equations of state: application to the NaCl pressure scale, J. Appl. Phys. 117:215902.

  8. Na+ transport in Acetabularia bypasses conductance of plasmalemma.

    PubMed

    Amtmann, A; Gradmann, D

    1994-04-01

    Na(+)-selective microelectrodes with the sensor ETH 227 have been used to measure the cytoplasmic Na+ concentration, [Na+]c, in Acetabularia. In the steady-state, [Na+]c is about 60 mM (external 460 mM). Steps in external Na+ concentration, [Na+]o, cause biexponential relaxations of [Na+]c which have formally been described by a serial three-compartment model (outside<==>compartment 1<==>compartment 2). From the initial slopes (some mMsec-1) net uptake and release of about 3 mumolm-2sec-1 Na+ are determined. Surprisingly, but consistent with previous tracer flux measurements (Mummert, H., Gradmann, D. 1991. J. Membrane Biol, 124:255-263), these Na+ fluxes are not accompanied by corresponding changes of the transplasmalemma voltage. [Na+]c is neither affected by the membrane voltage, nor by electrochemical gradients of H+ or Cl- across the plasmalemma, nor by cytoplasmic ATP. The results suggest a powerful vesicular transport system for ions which bypasses the conductance of the plasmalemma. In addition, transient increases of [Na+]c have been observed to take place facultatively during action potentials. The exponential distribution of the amplitudes of these transients (many small and few large peaks) points to local events in the more ore less close vicinity of the Na+ recording electrode. These events are suggested to consist of disruption of endoplasmic vesicles due to a loss of pressure in the cytoplasm.

  9. Genome Sequences of Cupriavidus metallidurans Strains NA1, NA4, and NE12, Isolated from Space Equipment.

    PubMed

    Monsieurs, Pieter; Mijnendonckx, Kristel; Provoost, Ann; Venkateswaran, Kasthuri; Ott, C Mark; Leys, Natalie; Van Houdt, Rob

    2014-01-01

    Cupriavidus metallidurans NA1, NA4, and NE12 were isolated from space and spacecraft-associated environments. Here, we report their draft genome sequences with the aim of gaining insight into their potential to adapt to these environments.

  10. Effects of altering the ATP/ADP ratio on pump-mediated Na/K and Na/Na exchanges in resealed human red blood cell ghosts

    PubMed Central

    1986-01-01

    Resealed human red blood cell ghosts were prepared to contain a range of ADP concentrations at fixed ATP concentrations and vice versa. ATP/ADP ratios ranging from approximately 0.2 to 50 were set and maintained (for up to 45 min) in this system. ATP and ADP concentrations were controlled by the addition of either a phosphoarginine- or phosphocreatine-based regenerating system. Ouabain- sensitive unidirectional Na efflux was determined in the presence and absence of 15 mM external K as a function of the nucleotide composition. Na/K exchange was found to increase to saturation with ATP (K 1/2 approximately equal to 250 microM), whereas Na/Na exchange (measured in K-free solutions) was a saturating function of ADP (K 1/2 approximately equal to 350 microM). The elevation of ATP from approximately 100 to 1,800 microM did not appreciably affect Na/Na exchange. In the presence of external Na and a saturating concentration of external K, increasing the ADP concentration at constant ATP was found to decrease ouabain-sensitive Na/K exchange. The decreased Na/K exchange that still remained when the ADP/ATP ratio was high was stimulated by removal of external Na. Assuming that under normal substrate conditions the reaction cycle of the Na/K pump is rate- limited by the conformational change associated with the release of occluded K [E2 X (K) X ATP----E1 X ATP + K], increasing ADP inhibits the rate of these transformations by competition with ATP for the E2(K) form. A less likely alternative is that inhibition is due to competition with ATP at the high-affinity site (E1). The acceleration of the Na/K pump that occurs upon removing external Na at high levels of ADP evidently results from a shift in the forward direction of the transformation of the intermediates involved with the release of occluded Na from E1P X (Na). Thus, the nucleotide composition and the Na gradient can modulate the rate at which the Na/K pump operates. PMID:3950576

  11. Zero-gravity growth of NaF-NaCl eutectics in the NASA Skylab program

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Allen, F. G.; Yu, J. G.

    1976-01-01

    Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, were produced in space and on earth. The production of continuous fibers in a eutectic mixture is attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It is shown that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis. A new concept is advanced to explain the phenomenon of transmittance versus far infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelengths is known. Experimental data are in agreement with the theoretical prediction.

  12. pNaKtide inhibits Na/K-ATPase reactive oxygen species amplification and attenuates adipogenesis

    PubMed Central

    Sodhi, Komal; Maxwell, Kyle; Yan, Yanling; Liu, Jiang; Chaudhry, Muhammad A.; Getty, Morghan; Xie, Zijian; Abraham, Nader G.; Shapiro, Joseph I.

    2015-01-01

    Obesity has become a worldwide epidemic and is a major risk factor for metabolic syndrome. Oxidative stress is known to play a role in the generation and maintenance of an obesity phenotype in both isolated adipocytes and intact animals. Because we had identified that the Na/K-ATPase can amplify oxidant signaling, we speculated that a peptide designed to inhibit this pathway, pNaKtide, might ameliorate an obesity phenotype. To test this hypothesis, we first performed studies in isolated murine preadipocytes (3T3L1 cells) and found that pNaKtide attenuated oxidant stress and lipid accumulation in a dose-dependent manner. Complementary experiments in C57Bl6 mice fed a high-fat diet corroborated our in vitro observations. Administration of pNaKtide in these mice reduced body weight gain, restored systemic redox and inflammatory milieu, and, crucially, improved insulin sensitivity. Thus, we propose that inhibition of Na/K-ATPase amplification of oxidative stress may ultimately be a novel way to combat obesity, insulin resistance, and metabolic syndrome. PMID:26601314

  13. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi.

    PubMed

    Dracatos, Peter M; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A; Plummer, Kim M

    2016-09-03

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2.

  14. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi

    PubMed Central

    Dracatos, Peter M.; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A.; Plummer, Kim M.

    2016-01-01

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2. PMID:27598152

  15. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi.

    PubMed

    Dracatos, Peter M; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A; Plummer, Kim M

    2016-01-01

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2. PMID:27598152

  16. Na+ channel function, regulation, structure, trafficking and sequestration

    PubMed Central

    Chen-Izu, Ye; Shaw, Robin M; Pitt, Geoffrey S; Yarov-Yarovoy, Vladimir; Sack, Jon T; Abriel, Hugues; Aldrich, Richard W; Belardinelli, Luiz; Cannell, Mark B; Catterall, William A; Chazin, Walter J; Chiamvimonvat, Nipavan; Deschenes, Isabelle; Grandi, Eleonora; Hund, Thomas J; Izu, Leighton T; Maier, Lars S; Maltsev, Victor A; Marionneau, Celine; Mohler, Peter J; Rajamani, Sridharan; Rasmusson, Randall L; Sobie, Eric A; Clancy, Colleen E; Bers, Donald M

    2015-01-01

    This paper is the second of a series of three reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on Na+ channel function and regulation, Na+ channel structure and function, and Na+ channel trafficking, sequestration and complexing. PMID:25772290

  17. Determination of Na(2)O from sodium aluminate NaAlO(2).

    PubMed

    Näykki, T; Raimo, A; Paavo, P; Antero, K; Päivi, N

    2000-07-31

    The aim of the work was to find a suitable method and conditions for determining Na(2)O wt.% from NaAlO(2). Problems were encountered while titrating NaAlO(2) with hydrochloric acid. The problematic area was the pH range 4-10 where aluminum precipitates as hydroxides. The different species of the aluminate solution were determined using potentiometric and complexometric titrations. The equivalent point of the potentiometric titration was detected using Gran's plotting method. Precipitation of aluminum hydroxides did not interfere with titrations, because in potentiometric titrations the pH value was over 10 and in complexometric titrations the pH was 4. The results were accurate and determinations were easy to carry out. Sodium was also determined by DCP-AES.

  18. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    SciTech Connect

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-07-15

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO{sub 2} and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 deg. C for 2-6 h by changing the SiO{sub 2}/Al{sub 2}O{sub 3}, H{sub 2}O/Na{sub 2}O and Na{sub 2}O/SiO{sub 2} molar ratios of precursors in the two-step process. The surface area and NH{sub 4}{sup +}-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m{sup 2}/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m{sup 2}/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of {approx}3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously. - Graphical Abstract: Novel Na-X zeolite/porous carbon composite.

  19. Specific oxidation pattern of soluble starch with TEMPO-NaBr-NaClO system.

    PubMed

    Hao, Jie; Lu, Jiaojiao; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing

    2016-08-01

    Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25°C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions.

  20. Specific oxidation pattern of soluble starch with TEMPO-NaBr-NaClO system.

    PubMed

    Hao, Jie; Lu, Jiaojiao; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing

    2016-08-01

    Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25°C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions. PMID:27112871

  1. Respiratory-driven Na+ electrical potential in the bacterium Vitreoscilla.

    PubMed

    Efiok, B J; Webster, D A

    1990-05-15

    Vitreoscilla is a Gram-negative bacterium with unique respiratory physiology in which Na+ was implicated as a coupling cation for the generation of a transmembrane electrical gradient (delta psi). Thus, cells respiring in the presence of 110 mM Na+ generated a delta psi of -142 mV compared to only -42 and -56 mV for Li+ and choline, respectively, and even the -42 and -56 mV were insensitive to the protonophore 3,5-di-tert-butyl-4-hydroxybenzaldehyde (DTHB). The kinetics of delta psi formation and collapse correlated well with the kinetics of Na+ fluxes but not with those of H+ fluxes. Cyanide inhibited respiration, Na+ extrusion, and delta psi formation 81% or more, indicating that delta psi formation and Na+ extrusion were coupled to respiration. Experiments were performed to distinguish among three possible transport systems for this coupling: (1) a Na(+)-transporting ATPase; (2) an electrogenic Na+/H+ antiport system; (3) a primary Na+ pump directly driven by the free energy of electron transport. DCCD and arsenate decreased cellular ATP up to 86% but had no effect on delta psi, evidence against a Na(+)-transporting ATPase. Low concentrations of DTHB had no effect on delta psi; high concentrations transiently collapsed delta psi, but led to a stimulation of Na+ extrusion, the opposite of that expected for a Na+/H+ antiport system. Potassium ion, which collapses delta psi, also stimulated Na+ extrusion. The experimental evidence is against Na+ extrusion by mechanisms 1 and 2 and supports the existence of a respiratory-driven primary Na+ pump for generating delta psi in Vitreoscilla. PMID:2372555

  2. Design and implementation of the NaI(Tl)/CsI(Na) detectors output signal generator

    NASA Astrophysics Data System (ADS)

    Zhou, Xu; Liu, Cong-Zhan; Zhao, Jian-Ling; Zhang, Fei; Zhang, Yi-Fei; Li, Zheng-Wei; Zhang, Shuo; Li, Xu-Fang; Lu, Xue-Feng; Xu, Zhen-Ling; Lu, Fang-Jun

    2014-02-01

    We designed and implemented a signal generator that can simulate the output of the NaI(Tl)/CsI(Na) detectors' pre-amplifier onboard the Hard X-ray Modulation Telescope (HXMT). Using the development of the FPGA (Field Programmable Gate Array) with VHDL language and adding a random constituent, we have finally produced the double exponential random pulse signal generator. The statistical distribution of the signal amplitude is programmable. The occurrence time intervals of the adjacent signals contain negative exponential distribution statistically.

  3. Direct Reactions with MoNA-LISA

    NASA Astrophysics Data System (ADS)

    Kuchera, Anthony

    2016-03-01

    Nuclear reactions can be used to probe the structure of nuclei. Direct reactions, which take place on short time scales, are well-suited for experiments with beams of short-lived nuclei. One such reaction is nucleon knockout where a proton or neutron is removed from the incoming beam from the interaction with a target. Single nucleon knockout reactions have been used to study the single-particle nature of nuclear wave functions. A recent experiment at the National Superconducting Cyclotron Laboratory was performed to measure cross sections from single nucleon knockout reactions for several p-shell nuclei. Detection of the residual nucleus in coincidence with any gamma rays emitted from the target allowed cross sections to ground and excited states to be measured. Together with input from reaction theory, ab initio structure theories can be tested. Simultaneously the accuracy of knockout reaction models can be validated by detecting the knocked out neutron with the Modular Neutron Array and Large multi-Institutional Scintillator Array (MoNA-LISA). Preliminary results from this experiment will be shown. Knockout reactions can also be used to populate nuclei which are neutron unbound, thus emit neutrons nearly instantaneously. The structure of these nuclei, therefore, cannot be probed with gamma ray spectroscopy. However, with large neutron detectors like MoNA-LISA the properties of these short-lived nuclei are able to be measured. Recent results using MoNA-LISA to study the structure of neutron-rich nuclei will be presented. The author would like to acknowledge support from the NNSA and NSF.

  4. The NA62 spectrometer acquisition system

    NASA Astrophysics Data System (ADS)

    Azorskiy, N.; Ceccucci, A.; Bendotti, J.; Danielsson, H.; Degrange, J.; Dixon, N.; Elsha, V.; Enik, T.; Glonti, L.; Gusakov, Y.; Kakurin, S.; Kekelidze, V.; Kislov, E.; Kolesnikov, A.; Koval, M.; Lichard, P.; Madigozhin, D.; Morant, J.; Movchan, S.; Perez Gomez, F.; Palladino, V.; Polenkevich, I.; Potrebenikov, Y.; Ruggiero, G.; Samsonov, V.; Shkarovskiy, S.; Sotnikov, A.

    2016-02-01

    The NA62 low mass spectrometer consists of 7000 straw tubes operating in vacuum. The front-end electronics is directly mounted on the detector and connected by a flexible PCB. The front-end board provides the amplification, shaping, discrimination and time measurements of the analogue signals from 16 channels. After digitisation the data is sent to a VME 9U read-out board. The data, once matched with the trigger, is sent to the next step and used by the trigger level 1 algorithm. The front-end and read-out systems of the detector will be presented along with the first results of the detector performances.

  5. [Effects of NaCl stress on the seedling growth and K(+)- and Na(+) -allocation of four leguminous tree species].

    PubMed

    Mo, Hai-Bo; Yin, Yun-Long; Lu, Zhi-Guo; Wei, Xiu-Jun; Xu, Jian-Hua

    2011-05-01

    Taking the pot-cultured seedlings of four leguminous tree species (Albizia julibrissin, Robinia pseudoacacia, Sophora japonica, and Gleditsia sinensis) as test materials, this paper studied their growth indices, critical salt concentration (C50), and K+ and Na+ allocation under different levels of NaCl stress, aimed to understand the difference of test tree species in salt tolerance. NaCl stress inhibited the seedling growth of the tree species. Under NaCl stress, the dry matter accumulation decreased, while the root/shoot ratio increased, especially for A. julibrissin and G. sinensis. Quadratic regression analysis showed that the C50 of A. julibrissin, R. pseudoacacia, S. japonica, and G. sinensis was 3.0 per thousand, 5.0 per thousand, 4.5 per thousand, and 3.9 per thousand, respectively, i.e., the salt tolerance of the four tree species was in the order of R. pseudoacacia > S. japonica > G. sinensis > A. julibrissin. In the root, stem, and leaf of the four tree species seedlings, the Na+ content increased with the increase of NaCl stress, while the K+ content (except in the root of A. julibrissin) decreased after an initial increase, resulting in a larger difference in the K+/Na+ ratio in the organs. Under the same NaCl stress, the allocation of Na+ in different organs of the four tree species seedlings decreased in the order of root>stem>leaf, while that of K+ differed with tree species and NaCl stress, and leaf was the main storage organ for K+. The K+/Na+ ratio in different organs decreased in the sequence of leaf>stem>root. R. pseudoacacia under NaCl stress accumulated more K+ and less Na+ in stem and leaf, and had higher K+/Na+ ratio in all organs and higher dry mass, being assessed to be more salt-tolerant. In contrast, A. julibrissin under high NaCl stress accumulated more Na+ in stem and leaf, and had a lower K+/Na+ ratio in all organs and lower dry mass, being evaluated to be lesser salt-tolerant. The K+ accumulation in seedling stem and leaf and the Na

  6. Asymmetry of Na-K-Cl cotransport in human erythrocytes.

    PubMed

    Kracke, G R; Anatra, M A; Dunham, P B

    1988-02-01

    The Na-K-Cl cotransport system in human erythrocytes was studied by measuring net influxes and effluxes of Na and K. The influx of K was shown to be stimulated by Na and the influx of Na was stimulated by K, satisfying the fundamental criterion of cotransport. In addition, these mutually stimulating cation influxes had a stoichiometry of 1:1 and were entirely inhibited by furosemide; these results are also consistent with cotransport. Furthermore, the mutually stimulating influxes were entirely dependent on Cl, since they were abolished when nitrate was substituted for Cl. In contrast, cotransport, defined by mutual dependence of fluxes, was not detected in the outward direction over a range of cellular Na and K concentrations from 0 to 50 mmol/l cells. The cotransport pathway did, however, appear to mediate a Na-stimulated K efflux (but no K-stimulated Na efflux), and furosemide-inhibitable effluxes of both Na and K. Nitrate (but not sulfate) appeared to substitute for chloride in promoting Na-stimulated K efflux. Thus the Na-K-Cl cotransport system in human red cells is intrinsically asymmetric, and mediates coupled cation fluxes readily only in the inward direction. PMID:3348364

  7. Hydrogen sulfide induced disruption of Na+ homeostasis in the cortex.

    PubMed

    Chao, Dongman; He, Xiaozhou; Yang, Yilin; Balboni, Gianfranco; Salvadori, Severo; Kim, Dong H; Xia, Ying

    2012-07-01

    Maintenance of ionic balance is essential for neuronal functioning. Hydrogen sulfide (H(2)S), a known toxic environmental gaseous pollutant, has been recently recognized as a gasotransmitter involved in numerous biological processes and is believed to play an important role in the neural activities under both physiological and pathological conditions. However, it is unclear if it plays any role in maintenance of ionic homeostasis in the brain under physiological/pathophysiological conditions. Here, we report by directly measuring Na(+) activity using Na(+) selective electrodes in mouse cortical slices that H(2)S donor sodium hydrosulfide (NaHS) increased Na(+) influx in a concentration-dependent manner. This effect could be partially blocked by either Na(+) channel blocker or N-methyl-D-aspartate receptor (NMDAR) blocker alone or almost completely abolished by coapplication of both blockers but not by non-NMDAR blocker. These data suggest that increased H(2)S in pathophysiological conditions, e.g., hypoxia/ischemia, potentially causes a disruption of ionic homeostasis by massive Na(+) influx through Na(+) channels and NMDARs, thus injuring neural functions. Activation of delta-opioid receptors (DOR), which reduces Na(+) currents/influx in normoxia, had no effect on H(2)S-induced Na(+) influx, suggesting that H(2)S-induced disruption of Na(+) homeostasis is resistant to DOR regulation and may play a major role in neuronal injury in pathophysiological conditions, e.g., hypoxia/ischemia.

  8. Minimizing Load Effects on NA4 Gear Vibration Diagnostic Parameter

    NASA Technical Reports Server (NTRS)

    Dempsey, Paula J.; Zakrajsek, James J.

    2001-01-01

    NA4 is a vibration diagnostic parameter, developed by researchers at NASA Glenn Research Center, for health monitoring of gears in helicopter transmissions. The NA4 reacts to the onset of gear pitting damage and continues to react to the damage as it spreads. This research also indicates NA4 reacts similarly to load variations. The sensitivity of NA4 to load changes will substantially affect its performance on a helicopter gearbox that experiences continuously changing load throughout its flight regimes. The parameter NA4 has been used to monitor gear fatigue tests at constant load. At constant load, NA4 effectively detects the onset of pitting damage and tracks damage severity. Previous research also shows that NA4 reacts to changes in load applied to the gears in the same way it reacts to the onset of pitting damage. The method used to calculate NA4 was modified to minimize these load effects. The modified NA4 parameter was applied to four sets of experimental data. Results indicate the modified NA4 is no longer sensitive to load changes, but remains sensitive to pitting damage.

  9. Naïve point estimation.

    PubMed

    Lindskog, Marcus; Winman, Anders; Juslin, Peter

    2013-05-01

    The capacity of short-term memory is a key constraint when people make online judgments requiring them to rely on samples retrieved from memory (e.g., Dougherty & Hunter, 2003). In this article, the authors compare 2 accounts of how people use knowledge of statistical distributions to make point estimates: either by retrieving precomputed large-sample representations or by retrieving small samples of similar observations post hoc at the time of judgment, as constrained by short-term memory capacity (the naïve sampling model: Juslin, Winman, & Hansson, 2007). Results from four experiments support the predictions by the naïve sampling model, including that participants sometimes guess values that they, when probed, demonstrably know have the lowest probability of occurring. Experiment 1 also demonstrated the operations of an unpredicted recognition-based inference. Computational modeling also incorporating this process demonstrated that the data from all 4 experiments were better predicted by assuming a post hoc sampling process constrained by short-term memory capacity than by assuming abstraction of large-sample representations of the distribution. PMID:22905935

  10. Apical Na+ permeability of frog skin during serosal Cl- replacement.

    PubMed

    Leibowich, S; DeLong, J; Civan, M M

    1988-05-01

    Gluconate substitution for serosal Cl- reduces the transepithelial short-circuit current (Isc) and depolarizes short-circuited frog skins. These effects could result either from inhibition of basolateral K+ conductance, or from two actions to inhibit both apical Na+ permeability (PapNa) and basolateral pump activity. We have addressed this question by studying whole-and split-thickness frog skins. Intracellular Na+ concentration (CcNa) and PapNa have been monitored by measuring the current-voltage relationship for apical Na+ entry. This analysis was conducted by applying trains of voltage pulses, with pulse durations of 16 to 32 msec. Estimates of PapNa and CcNa were not detectably dependent on pulse duration over the range 16 to 80 msec. Serosal Cl- replacement uniformly depolarized short-circuited tissues. The depolarization was associated with inhibition of Isc across each split skin, but only occasionally across the whole-thickness preparations. This difference may reflect the better ionic exchange between the bulk medium and the extracellular fluid in contact with the basolateral membranes, following removal of the underlying dermis in the split-skin preparations. PapNa was either unchanged or increased, and CcNa either unchanged or reduced after the anionic replacement. These data are incompatible with the concept that serosal Cl- replacement inhibits PapNa and Na,K-pump activity. Gluconate substitution likely reduces cell volume, triggering inhibition of the basolateral K+ channels, consistent with the data and conclusions of S.A. Lewis, A.G. Butt, M.J. Bowler, J.P. Leader and A.D.C. Macknight (J. Membrane Biol. 83:119-137, 1985) for toad bladder. The resulting depolarization reduces the electrical force favoring apical Na+ entry. The volume-conductance coupling serves to conserve volume by reducing K+ solute loss. Its molecular basis remains to be identified.

  11. Interaction of the Na+-K+ pump and Na+-Ca2+ exchange via [Na+]i in a restricted space of guinea-pig ventricular cells.

    PubMed

    Fujioka, Y; Matsuoka, S; Ban, T; Noma, A

    1998-06-01

    1. The whole-cell Na+-K+ pump current (INa-K) and Na+-Ca2+ exchange current (INa-Ca) were recorded in guinea-pig ventricular myocytes to study the interaction between the two Na+ transport mechanisms. 2. INa-K was isolated as an external K+-induced current, and INa-Ca as an external Ca2+- induced or Ni2+-sensitive current. The experimental protocol used for one ion carrier did not affect the other. 3. The amplitude of INa-K decreased to 54 +/- 17 % of the initial peak during continuous application of K+ with 20 mM Na+ in the pipette. The outward INa-Ca, which was intermittently activated by brief applications of Ca2+, decreased during activation of INa-K, and recovered after cessation of INa-K activation. These findings revealed a dynamic interaction between INa-K and INa-Ca via a depletion of Na+ under the sarcolemma. 4. To estimate changes in Na+ concentration ([Na+]i) under the sarcolemma, the reversal potential (Vrev) of INa-Ca was measured. Unexpectedly, Vrev hardly changed during activation of INa-K. However, when INa-Ca was blocked by Ni2+ at the same time that INa-K was activated, Vrev changed markedly, maximally by +100 mV, immediately after the removal of Ni2+ and K+. 5. Subsarcolemmal [Na+]i was calculated from the Vrev of INa-Ca on the assumption that the subsarcolemmal Ca2+ concentration ([Ca2+]i) was fixed with EGTA, and mean [Na+]i was calculated from both the time integral of INa-K and the cell volume. The subsarcolemmal [Na+]i was about seven times greater than the mean [Na+]i. 6. The interaction between the Na+-K+ pump and Na+-Ca2+ exchange was well simulated by a diffusion model, in which Na+ diffusion was restricted to one-seventh (14 %) of the total cell volume.

  12. Regulation of persistent Na current by interactions between β subunits of voltage-gated Na channels

    PubMed Central

    Aman, Teresa K.; Grieco-Calub, Tina M.; Chen, Chunling; Rusconi, Raffaella; Slat, Emily A.; Isom, Lori L.; Raman, Indira M.

    2009-01-01

    The β subunits of voltage-gated Na channels (Scnxb) regulate the gating of pore-forming α subunits, as well as their trafficking and localization. In heterologous expression systems, β1, β2, and β3 subunits influence inactivation and persistent current in different ways. To test how the β4 protein regulates Na channel gating, we transfected β4 into HEK cells stably expressing NaV1.1. Unlike a free peptide with a sequence from the β4 cytoplasmic domain, the full-length β4 protein did not block open channels. Instead, β4 expression favored open states by shifting activation curves negative, decreasing the slope of the inactivation curve, and increasing the percentage of non-inactivating current. Consequently, persistent current tripled in amplitude. Expression of β1 or chimeric subunits including the β1 extracellular domain, however, favored inactivation. Co-expressing NaV1.1 and β4 with β1 produced tiny persistent currents, indicating that β1 overcomes the effects of β4 in heterotrimeric channels. In contrast, β1C121W, which contains an extracellular epilepsy-associated mutation, did not counteract the destabilization of inactivation by β4, and also required unusually large depolarizations for channel opening. In cultured hippocampal neurons transfected with β4, persistent current was slightly but significantly increased. Moreover, in β4-expressing neurons from Scn1b and Scn1b/Scn2b null mice, entry into inactivated states was slowed. These data suggest that β1 and β4 have antagonistic roles, the former favoring inactivation and the latter favoring activation. Because increased Na channel availability may facilitate action potential firing, these results suggest a mechanism for seizure susceptibility of both mice and humans with disrupted β1 subunits. PMID:19228957

  13. [Na] and [K] dependence of the Na/K pump current-voltage relationship in guinea pig ventricular myocytes

    PubMed Central

    1989-01-01

    Na/K pump current was determined between -140 and +60 mV as steady- state, strophanthidin-sensitive, whole-cell current in guinea pig ventricular myocytes, voltage-clamped and internally dialyzed via wide- tipped pipettes. Solutions were designed to minimize all other components of membrane current. A device for exchanging the solution inside the pipette permitted investigation of Na/K pump current-voltage (I-V) relationships at several levels of pipette [Na] [( Na]pip) in a single cell; the effects of changes in external [Na] [( Na]o) or external [K] [( K]o) were also studied. At 50 mM [Na]pip, 5.4 mM [K]o, and approximately 150 mM [Na]o, Na/K pump current was steeply voltage dependent at negative potentials but was approximately constant at positive potentials. Under those conditions, reduction of [Na]o enhanced pump current at negative potentials but had little effect at positive potentials: at zero [Na]o, pump current was only weakly voltage dependent. At 5.4 mM [K]o and approximately 150 mM [Na]o, reduction of [Na]pip from 50 mM scaled down the sigmoid pump I-V relationship and shifted it slightly to the right (toward more positive potentials). Pump current at 0 mV was activated by [Na]pip according to the Hill equation with best-fit K0.5 approximately equal to 11 mM and Hill coefficient nH approximately equal to 1.4. At zero [Na]o, reduction of [Na]pip seemed to simply scale down the relatively flat pump I-V relationship: Hill fit parameters for pump activation by [Na]pip at 0 mV were K0.5 approximately equal to 10 mM, nH approximately equal to 1.4. At 50 mM [Na]pip and high [Na]o, reduction of [K]o from 5.4 mM scaled down the sigmoid I-V relationship and shifted it slightly to the right: at 0 mV, K0.5 approximately equal to 1.5 mM and nH approximately equal to 1.0. At zero [Na]o, lowering [K]o simply scaled down the flat pump I-V relationships yielding, at 0 mV, K0.5 approximately equal to 0.2 mM, nH approximately equal to 1.1. The voltage

  14. Coordinated regulation of cardiac Na(+)/Ca (2+) exchanger and Na (+)-K (+)-ATPase by phospholemman (FXYD1).

    PubMed

    Cheung, Joseph Y; Zhang, Xue-Qian; Song, Jianliang; Gao, Erhe; Chan, Tung O; Rabinowitz, Joseph E; Koch, Walter J; Feldman, Arthur M; Wang, JuFang

    2013-01-01

    Phospholemman (PLM) is the founding member of the FXYD family of regulators of ion transport. PLM is a 72-amino acid protein consisting of the signature PFXYD motif in the extracellular N terminus, a single transmembrane (TM) domain, and a C-terminal cytoplasmic tail containing three phosphorylation sites. In the heart, PLM co-localizes and co-immunoprecipitates with Na(+)-K(+)-ATPase, Na(+)/Ca(2+) exchanger, and L-type Ca(2+) channel. The TM domain of PLM interacts with TM9 of the α-subunit of Na(+)-K(+)-ATPase, while its cytoplasmic tail interacts with two small regions (spanning residues 248-252 and 300-304) of the proximal intracellular loop of Na(+)/Ca(2+) exchanger. Under stress, catecholamine stimulation phosphorylates PLM at serine(68), resulting in relief of inhibition of Na(+)-K(+)-ATPase by decreasing K(m) for Na(+) and increasing V(max), and simultaneous inhibition of Na(+)/Ca(2+) exchanger. Enhanced Na(+)-K(+)-ATPase activity lowers intracellular Na(+), thereby minimizing Ca(2+) overload and risks of arrhythmias. Inhibition of Na(+)/Ca(2+) exchanger reduces Ca(2+) efflux, thereby preserving contractility. Thus, the coordinated actions of PLM during stress serve to minimize arrhythmogenesis and maintain inotropy. In acute cardiac ischemia and chronic heart failure, either expression or phosphorylation of PLM or both are altered. PLM regulates important ion transporters in the heart and offers a tempting target for development of drugs to treat heart failure.

  15. Quantitative 23Na magnetic resonance imaging of model foods.

    PubMed

    Veliyulin, Emil; Egelandsdal, Bjørg; Marica, Florin; Balcom, Bruce J

    2009-05-27

    Partial (23)Na MRI invisibility in muscle foods is often referred to as an inherent drawback of the MRI technique, impairing quantitative sodium analysis. Several model samples were designed to simulate muscle foods with a broad variation in protein, fat, moisture, and salt content. (23)Na spin-echo MRI and a recently developed (23)Na SPRITE MRI approach were compared for quantitative sodium imaging, demonstrating the possibility of accurate quantitative (23)Na MRI by the latter method. Good correlations with chemically determined standards were also obtained from bulk (23)Na free induction decay (FID) and CPMG relaxation experiments on the same sample set, indicating their potential use for rapid bulk NaCl measurements. Thus, the sodium MRI invisibility is a methodological problem that can easily be circumvented by using the SPRITE MRI technique. PMID:21314196

  16. Pyrophosphate-fueled Na+ and H+ transport in prokaryotes.

    PubMed

    Baykov, Alexander A; Malinen, Anssi M; Luoto, Heidi H; Lahti, Reijo

    2013-06-01

    In its early history, life appeared to depend on pyrophosphate rather than ATP as the source of energy. Ancient membrane pyrophosphatases that couple pyrophosphate hydrolysis to active H(+) transport across biological membranes (H(+)-pyrophosphatases) have long been known in prokaryotes, plants, and protists. Recent studies have identified two evolutionarily related and widespread prokaryotic relics that can pump Na(+) (Na(+)-pyrophosphatase) or both Na(+) and H(+) (Na(+),H(+)-pyrophosphatase). Both these transporters require Na(+) for pyrophosphate hydrolysis and are further activated by K(+). The determination of the three-dimensional structures of H(+)- and Na(+)-pyrophosphatases has been another recent breakthrough in the studies of these cation pumps. Structural and functional studies have highlighted the major determinants of the cation specificities of membrane pyrophosphatases and their potential use in constructing transgenic stress-resistant organisms.

  17. Simulation of Na D emission near Europa during eclipse

    USGS Publications Warehouse

    Cassidy, T.A.; Johnson, R.E.; Geissler, P.E.; Leblanc, F.

    2008-01-01

    The Cassini imaging science subsystem observed Europa in eclipse during Cassini's Jupiter flyby. The disk-resolved observations revealed a spatially nonuniform emission in the wavelength range of 200-1050 nm (clear filters). By building on observations and simulations of Europa's Na atmosphere and torus we find that electron-excited Na in Europa's tenuous atmosphere can account for the observed emission if the Na is ejected preferentially from Europa's dark terrain. Copyright 2008 by the American Geophysical Union.

  18. Magnesium correction to the NaKCa chemical geothermometer

    USGS Publications Warehouse

    Fournier, R.O.; Potter, R.W., II

    1979-01-01

    Equations and graphs have been devised to correct for the adverse effects of magnesium upon the Na-K-Ca chemical geothermometer. Either the equations or graphs can be used to determine appropriate temperature corrections for given waters with calculated NaKCa temperatures > 70??C and R 50 are probably derived from relatively cool aquifers with temperatures approximately equal to the measured spring temperature, irrespective of much higher calculated Na-K-Ca temperatures. ?? 1979.

  19. Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3

    NASA Astrophysics Data System (ADS)

    Yahia, H. Ben; Essehli, R.; Avdeev, M.; Park, J.-B.; Sun, Y.-K.; Al-Maadeed, M. A.; Belharouak, I.

    2016-06-01

    The new compounds NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 crystallize with a stuffed α-CrPO4-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structures of NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 a statistical disorder Ni2+/Cr3+ was observed on both the 8g and 4a atomic positions, whereas in NaCoCr2(PO4)3 the statistical disorder Co2+/Cr3+ was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 delivered specific capacities of 352, 385, and 368 mA h g-1, respectively, which attests to the electrochemical activity of sodium in these compounds.

  20. Advanced Intermediate-Temperature Na-S Battery

    SciTech Connect

    Lu, Xiaochuan; Kirby, Brent W.; Xu, Wu; Li, Guosheng; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo

    2012-11-12

    In this study, we reported an intermediate-temperature (~150°C) sodium-sulfur (Na-S) battery. With a reduced operating temperature, this novel battery can potentially reduce the cost and safety issues associated with the conventional high-temperature (300~350°C) Na-S battery. A dense β"-Al2O3 solid membrane and tetraglyme were utilized as the electrolyte separator and catholyte solvent in this battery. Solubility tests indicated that cathode mixture of Na2S4 and S exhibited extremely high solubility in tetraglyme (e.g., > 4.1 M for Na2S4 + 4 S). CV scans of Na2S4 in tetraglyme revealed two pairs of redox couples with peaks at around 2.22 and 1.75 V, corresponding to the redox reactions of polysulfide species. The discharge/charge profiles of the Na-S battery showed a slope region and a plateau, indicating multiple steps and cell reactions. In-situ Raman measurements during battery operation suggested that polysulfide species were formed in the sequence of Na2S5 + S → Na2S5 + Na2S4Na2S4 + Na2S2 during discharge and in a reverse order during charge. This battery showed dramatic improvement in rate capacity and cycling stability over room-temperature Na-S batteries, which makes it attractive for renewable energy integration and other grid related applications.

  1. Effects of Cl adatom on Na-Decorated graphene

    NASA Astrophysics Data System (ADS)

    Song, Xinxiang; Sun, Yu; Dong, Meifeng; Li, Chun; Wang, Jiesheng; Mimura, Hidenori; Yuan, Guang

    2015-06-01

    The effects of the Cl adatom on Na-decorated graphene are studied using first principles density functional theory under the generalized gradient approximation to calculate the adsorption energy, geometric structure, charge density difference, and density of states. When Na and Cl adatoms are simultaneously absorbed on opposite sides of graphene, the adsorption energy of Na increases by about 1 eV and the adsorption system becomes more stable because graphene can effectively transfer the 3s valence of the Na adatom to the Cl adatom.

  2. Transcriptional regulators of Na,K-ATPase subunits

    PubMed Central

    Li, Zhiqin; Langhans, Sigrid A.

    2015-01-01

    The Na,K-ATPase classically serves as an ion pump creating an electrochemical gradient across the plasma membrane that is essential for transepithelial transport, nutrient uptake and membrane potential. In addition, Na,K-ATPase also functions as a receptor, a signal transducer and a cell adhesion molecule. With such diverse roles, it is understandable that the Na,K-ATPase subunits, the catalytic α-subunit, the β-subunit and the FXYD proteins, are controlled extensively during development and to accommodate physiological needs. The spatial and temporal expression of Na,K-ATPase is partially regulated at the transcriptional level. Numerous transcription factors, hormones, growth factors, lipids, and extracellular stimuli modulate the transcription of the Na,K-ATPase subunits. Moreover, epigenetic mechanisms also contribute to the regulation of Na,K-ATPase expression. With the ever growing knowledge about diseases associated with the malfunction of Na,K-ATPase, this review aims at summarizing the best-characterized transcription regulators that modulate Na,K-ATPase subunit levels. As abnormal expression of Na,K-ATPase subunits has been observed in many carcinoma, we will also discuss transcription factors that are associated with epithelial-mesenchymal transition, a crucial step in the progression of many tumors to malignant disease. PMID:26579519

  3. Kaolin-based geopolymers with various NaOH concentrations

    NASA Astrophysics Data System (ADS)

    Heah, C. Y.; Kamarudin, H.; Mustafa Al Bakri, A. M.; Bnhussain, M.; Luqman, M.; Khairul Nizar, I.; Ruzaidi, C. M.; Liew, Y. M.

    2013-03-01

    Kaolin geopolymers were produced by the alkali-activation of kaolin with an activator solution (a mixture of NaOH and sodium silicate solutions). The NaOH solution was prepared at a concentration of 6-14 mol/L and was mixed with the sodium silicate solution at a Na2SiO3/NaOH mass ratio of 0.24 to prepare an activator solution. The kaolin-to-activator solution mass ratio used was 0.80. This paper aimed to analyze the effect of NaOH concentration on the compressive strength of kaolin geopolymers at 80°C for 1, 2, and 3 d. Kaolin geopolymers were stable in water, and strength results showed that the kaolin binder had adequate compressive strength with 12 mol/L of NaOH concentration. When the NaOH concentration increased, the SiO2/Na2O decreased. The increased Na2O content enhanced the dissolution of kaolin as shown in X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses. However, excess in this content was not beneficial for the strength development of kaolin geopolymers. In addition, there was the formation of more geopolymeric gel in 12 mol/L samples. The XRD pattern of the samples showed a higher amorphous content and a more geopolymer bonding existed as proved by FTIR analysis.

  4. Influenza virus neuraminidase (NA): a target for antivirals and vaccines.

    PubMed

    Jagadesh, Anitha; Salam, Abdul Ajees Abdul; Mudgal, Piya Paul; Arunkumar, Govindakarnavar

    2016-08-01

    Influenza, the most common infectious disease, poses a great threat to human health because of its highly contagious nature and fast transmissibility, often leading to high morbidity and mortality. Effective vaccination strategies may aid in the prevention and control of recurring epidemics and pandemics associated with this infectious disease. However, antigenic shifts and drifts are major concerns with influenza virus, requiring effective global monitoring and updating of vaccines. Current vaccines are standardized primarily based on the amount of hemagglutinin, a major surface antigen, which chiefly constitutes these preparations along with the varying amounts of neuraminidase (NA). Anti-influenza drugs targeting the active site of NA have been in use for more than a decade now. However, NA has not been approved as an effective antigenic component of the influenza vaccine because of standardization issues. Although some studies have suggested that NA antibodies are able to reduce the severity of the disease and induce a long-term and cross-protective immunity, a few major scientific issues need to be addressed prior to launching NA-based vaccines. Interestingly, an increasing number of studies have shown NA to be a promising target for future influenza vaccines. This review is an attempt to consolidate studies that reflect the strength of NA as a suitable vaccine target. The studies discussed in this article highlight NA as a potential influenza vaccine candidate and support taking the process of developing NA vaccines to the next stage. PMID:27255748

  5. Study of OSL in NaF: Ca,Cu

    NASA Astrophysics Data System (ADS)

    More, Y. K.; Wankhede, S. P.; Moharil, S. V.

    2013-06-01

    Sodium Fluoride containing Cu+ ions was prepared by R.A.P. followed by melt-quenching technique. Results on photo, thermo and optically stimulated luminescence in NaF:Ca,Cu are reported. OSL sensitivity of NaF:Ca,Cu is approximately 2 times than that of standard phosphor LMP. The rate of OSL depletion for 90% decay for NaF:Ca,Cu is 0.3 times as that of OSL phosphor LMP. NaF:Ca,Cu thus deserves much more attention than it has received up till now.

  6. Pion and kaon freezeout in NA44

    SciTech Connect

    NA44 Collaboration

    1994-12-01

    The NA44 spectrometer is optimized for the study of single and two-particle particle spectra near mid-rapidity for transverse momenta below {approx} 1 GeV/c. A large fraction of all pairs in the spectrometer`s acceptance are at low relative momenta, resulting in small statistical uncertainties on the extracted size parameters. In addition, the spectrometer`s clean particle identification allows the authors to measure correlation functions for pions, kaons, and protons. This contribution will concentrate on the source size parameters determined from pion and kaon correlation functions. These size parameters will be compared to calculations from the RQMD event generator and also interpreted in the context of a hydrodynamic model. Finally, the measured single particle spectra will be examined from the viewpoint of hydrodynamics.

  7. Mercury's Na Exosphere from MESSENGER Data

    NASA Technical Reports Server (NTRS)

    Killen, Rosemary M.; Burger, M. H.; Cassidy, T. A.; Sarantos, M.; Vervack, R. J.; McClintock, W. El; Merkel, A. W.; Sprague, A. L.; Solomon, S. C.

    2012-01-01

    MESSENGER entered orbit about Mercury on March 18, 2011. Since then, the Ultraviolet and Visible Spectrometer (UWS) channel of MESSENGER's Mercury Atmospheric and Surface Composition Spectrometer (MASCS) has been observing Mercury's exosphere nearly continuously. Daily measurements of Na brightness were fitted with non-uniform exospheric models. With Monte Carlo sampling we traced the trajectories of a representative number of test particles, generally one million per run per source process, until photoionization, escape from the gravitational well, or permanent sticking at the surface removed the atom from the simulation. Atoms were assumed to partially thermally accommodate on each encounter with the surface with accommodation coefficient 0.25. Runs for different assumed source processes are run separately, scaled and co-added. Once these model results were saved onto a 3D grid, we ran lines of sight from the MESSENGER spacecraft :0 infinity using the SPICE kernels and we computed brightness integrals. Note that only particles that contribute to the measurement can be constrained with our method. Atoms and molecules produced on the nightside must escape the shadow in order to scatter light if the excitation process is resonant-light scattering, as assumed here. The aggregate distribution of Na atoms fits a 1200 K gas, with a PSD distribution, along with a hotter component. Our models constrain the hot component, assumed to be impact vaporization, to be emitted with a 2500 K Maxwellian. Most orbits show a dawnside enhancement in the hot component broadly spread over the leading hemisphere. However, on some dates there is no dawn/dusk asymmetry. The portion of the hot/cold source appears to be highly variable.

  8. The naïve intuitive statistician: a naïve sampling model of intuitive confidence intervals.

    PubMed

    Juslin, Peter; Winman, Anders; Hansson, Patrik

    2007-07-01

    The perspective of the naïve intuitive statistician is outlined and applied to explain overconfidence when people produce intuitive confidence intervals and why this format leads to more overconfidence than other formally equivalent formats. The naïve sampling model implies that people accurately describe the sample information they have but are naïve in the sense that they uncritically take sample properties as estimates of population properties. A review demonstrates that the naïve sampling model accounts for the robust and important findings in previous research as well as provides novel predictions that are confirmed, including a way to minimize the overconfidence with interval production. The authors discuss the naïve sampling model as a representative of models inspired by the naïve intuitive statistician. PMID:17638502

  9. Melting properties of radiation-induced Na and Cl2 precipitates in ultra-heavily irradiated NaCl

    NASA Astrophysics Data System (ADS)

    Sugonyako, A. V.; Vainshtein, D. I.; den Hartog, H. P.; Turkin, A. A.; den Hartog, H. W.

    2005-01-01

    Exposure of NaCl to high doses of ionizing radiation leads to the formation of nano-particles of metallic Na, very small chlorine precipitates, vacancy voids, and dislocations. A useful way to monitor the stage of the damage formation process is measuring the latent heat of melting of the Na-particles (100 °C) and chlorine precipitates (-101 °C). In this paper we will present data, showing that for doses in the range of TRad (1010 Gy) the concentration of radiolytic Na may become very large. Even in pure samples, we have converted more than 20% of all NaCl molecules into metallic Na and chlorine, but often higher percentages can be achieved. In this paper we will present new data obtained for ultra-high irradiation doses and a first attempt will be made to understand the results.

  10. Attenuation of Na/K-ATPase Mediated Oxidant Amplification with pNaKtide Ameliorates Experimental Uremic Cardiomyopathy

    PubMed Central

    Liu, Jiang; Tian, Jiang; Chaudhry, Muhammad; Maxwell, Kyle; Yan, Yanling; Wang, Xiaoliang; Shah, Preeya T.; Khawaja, Asad A.; Martin, Rebecca; Robinette, Tylor J.; El-Hamdani, Adee; Dodrill, Michael W.; Sodhi, Komal; Drummond, Christopher A.; Haller, Steven T.; Kennedy, David J.; Abraham, Nader G.; Xie, Zijian; Shapiro, Joseph I.

    2016-01-01

    We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic cardiomyopathy reversed many of the phenotypical features. Attenuation of Na/K-ATPase oxidant amplification may be a potential strategy for clinical therapy of this disorder. PMID:27698370

  11. RNA adducts with Na 2SeO 4 and Na 2SeO 3 - Stability and structural features

    NASA Astrophysics Data System (ADS)

    Nafisi, Shohreh; Manouchehri, Firouzeh; Montazeri, Maryam

    2011-12-01

    Selenium compounds are widely available in dietary supplements and have been extensively studied for their antioxidant and anticancer properties. Low blood Se levels were found to be associated with an increased incidence and mortality from various types of cancers. Although many in vivo and clinical trials have been conducted using these compounds, their biochemical and chemical mechanisms of efficacy are the focus of much current research. This study was designed to examine the interaction of Na 2SeO 4 and Na 2SeO 3 with RNA in aqueous solution at physiological conditions, using a constant RNA concentration (6.25 mM) and various sodium selenate and sodium selenite/polynucleotide (phosphate) ratios of 1/80, 1/40, 1/20, 1/10, 1/5, 1/2 and 1/1. Fourier transform infrared, UV-Visible spectroscopic methods were used to determine the drug binding modes, the binding constants, and the stability of Na 2SeO 4 and Na 2SeO 3-RNA complexes in aqueous solution. Spectroscopic evidence showed that Na 2SeO 4 and Na 2SeO 3 bind to the major and minor grooves of RNA ( via G, A and U bases) with some degree of the Se-phosphate (PO 2) interaction for both compounds with overall binding constants of K(Na 2SeO 4-RNA) = 8.34 × 10 3 and K(Na 2SeO 3-RNA) = 4.57 × 10 3 M -1. The order of selenium salts-biopolymer stability was Na 2SeO 4-RNA > Na 2SeO 3-RNA. RNA aggregations occurred at higher selenium concentrations. No biopolymer conformational changes were observed upon Na 2SeO 4 and Na 2SeO 3 interactions, while RNA remains in the A-family structure.

  12. Solubility of MgO in MgCl{sub 2}-NaCl-NaF melts

    SciTech Connect

    Mediaas, H.; Vinstad, J.E.; Oestvold, T.

    1996-10-01

    The solubility of MgO in MgCl{sub 2}-NaCl-NaF melts has been measured for melts with varying NaF concentration for x{sub MgCl{sub 2}} = 0.10 and 0.63 and for x{sub MgCl{sub 2}}/x{sub NaCl} = 1.70. Melt samples have been analyzed by carbothermal reduction (Leco TC-436) for total oxide content. The oxide content in the binary melt MgCl{sub 2}-NaCl was also analyzed by Iodometric titration. The results indicate two different oxide-containing species, denoted MgOCl and MgOF, in the solidified samples withdrawn from the melt. The latter appears only in fluoride-containing melts, but may, however, also contain chloride ions. The oxide solubility is increasing with increasing concentration of Mg{sup 2+} in both MgCl{sub 2}-NaCl and MgCl{sub 2}-NaCl-NaF melts. The solubility of MgO is always higher in fluoride containing melts at the same Mg{sup 2+} concentration. In the systems concentrated in MgCl{sub 2}, the increase in oxide solubility as function of x{sub NaF} is more pronounced than what is predicted from a simple model calculation. The increase is much smaller in the x{sub NaF} < 0.2 range for small MgCl{sub 2} contents than predicted from the same model calculation. The introduction of 1.7 mol% NaF to an industrial electrolyte does not seem to change the oxide solubility significantly. In such an electrolyte, where x{sub MgCl{sub 2}} {approx_equal} 0.1, the data gives a constant oxide solubility around 10 ppm O up to 5 mol% NaF.

  13. Elevated [Cl-]i, and [Na+]i inhibit Na+, K+, Cl- cotransport by different mechanisms in squid giant axons

    PubMed Central

    1996-01-01

    Bumetanide-sensitive (BS) unidirectional fluxes of (36)Cl- or (22)Na+ were measured in internally dialyzed squid giant axons while varying the intra- or extracellular concentrations of Na+ and/or Cl-. Raising either [Cl-]i or [Na+]i resulted in a concentration-dependent reduction of the BS influx of both (36)Cl- and (22)Na+. Raising [Cl-]i above 200 mM completely blocked BS influxes. However, raising [Na+]i to 290 mM resulted in saturable but incomplete inhibition of both BS Na+ influx and BS Cl- influx. The consequences of varying intracellular Cl- on cotransporter effluxes were complex. At lower [Cl-]i values (below 100 mM) intracellular Cl- activated cotransporter effluxes. Surprisingly, however, raising [Cl-]i levels > 125 mM resulted in a [Cl-]i-dependent inhibition of BS effluxes of both Na+ and Cl-. On the other hand, raising [Na+]i resulted only in the activation of the BS Na+ efflux; intracellular Na+ did not inhibit BS efflux even at 290 mM. The inhibitory effects of intracellular Na+ on cotransporter-mediated influxes, and lack of inhibitory effects on BS effluxes, are consistent with the trans-side inhibition expected for an ordered binding/release model of cotransporter operation. However, the inhibitory effects of intracellular Cl- on both influxes and effluxes are not explained by such a model. These data suggest that Cl may interact with an intracellular site (or sites), which does not mediate Cl transport, but does modulate the transport activity of the Na+, K+, Cl- cotransporter. PMID:8833345

  14. Elevated [Cl-]i, and [Na+]i inhibit Na+, K+, Cl- cotransport by different mechanisms in squid giant axons.

    PubMed

    Breitwieser, G E; Altamirano, A A; Russell, J M

    1996-02-01

    Bumetanide-sensitive (BS) unidirectional fluxes of (36)Cl- or (22)Na+ were measured in internally dialyzed squid giant axons while varying the intra- or extracellular concentrations of Na+ and/or Cl-. Raising either [Cl-]i or [Na+]i resulted in a concentration-dependent reduction of the BS influx of both (36)Cl- and (22)Na+. Raising [Cl-]i above 200 mM completely blocked BS influxes. However, raising [Na+]i to 290 mM resulted in saturable but incomplete inhibition of both BS Na+ influx and BS Cl- influx. The consequences of varying intracellular Cl- on cotransporter effluxes were complex. At lower [Cl-]i values (below 100 mM) intracellular Cl- activated cotransporter effluxes. Surprisingly, however, raising [Cl-]i levels > 125 mM resulted in a [Cl-]i-dependent inhibition of BS effluxes of both Na+ and Cl-. On the other hand, raising [Na+]i resulted only in the activation of the BS Na+ efflux; intracellular Na+ did not inhibit BS efflux even at 290 mM. The inhibitory effects of intracellular Na+ on cotransporter-mediated influxes, and lack of inhibitory effects on BS effluxes, are consistent with the trans-side inhibition expected for an ordered binding/release model of cotransporter operation. However, the inhibitory effects of intracellular Cl- on both influxes and effluxes are not explained by such a model. These data suggest that Cl may interact with an intracellular site (or sites), which does not mediate Cl transport, but does modulate the transport activity of the Na+, K+, Cl- cotransporter.

  15. A 23Na magic angle spinning nuclear magnetic resonance, XANES, and high-temperature X-ray diffraction study of NaUO3, Na4UO5, and Na2U2O7.

    PubMed

    Smith, A L; Raison, P E; Martel, L; Charpentier, T; Farnan, I; Prieur, D; Hennig, C; Scheinost, A C; Konings, R J M; Cheetham, A K

    2014-01-01

    The valence state of uranium has been confirmed for the three sodium uranates NaU(V)O3/[Rn](5f(1)), Na4U(VI)O5/[Rn](5f(0)), and Na2U(VI)2O7/[Rn](5f(0)), using X-ray absorption near-edge structure (XANES) spectroscopy. Solid-state (23)Na magic angle spinning nuclear magnetic resonance (MAS NMR) measurements have been performed for the first time, yielding chemical shifts at -29.1 (NaUO3), 15.1 (Na4UO5), and -14.1 and -19 ppm (Na1 8-fold coordinated and Na2 7-fold coordinated in Na2U2O7), respectively. The [Rn]5f(1) electronic structure of uranium in NaUO3 causes a paramagnetic shift in comparison to Na4UO5 and Na2U2O7, where the electronic structure is [Rn]5f(0). A (23)Na multi quantum magic angle spinning (MQMAS) study on Na2U2O7 has confirmed a monoclinic rather than rhombohedral structure with evidence for two distinct Na sites. DFT calculations of the NMR parameters on the nonmagnetic compounds Na4UO5 and Na2U2O7 have permitted the differentiation between the two Na sites of the Na2U2O7 structure. The linear thermal expansion coefficients of all three compounds have been determined using high-temperature X-ray diffraction: αa = 22.7 × 10(-6) K(-1), αb = 12.9 × 10(-6) K(-1), αc = 16.2 × 10(-6) K(-1), and αvol = 52.8 × 10(-6) K(-1) for NaUO3 in the range 298-1273 K; αa = 37.1 × 10(-6) K(-1), αc = 6.2 × 10(-6) K(-1), and αvol = 81.8 × 10(-6) K(-1) for Na4UO5 in the range 298-1073 K; αa = 6.7 × 10(-6) K(-1), αb = 14.4 × 10(-6) K(-1), αc = 26.8 × 10(-6) K(-1), αβ = -7.8 × 10(-6) K(-1), and αvol = -217.6 × 10(-6) K(-1) for Na2U2O7 in the range 298-573 K. The α to β phase transition reported for the last compound above about 600 K was not observed in the present studies, either by high-temperature X-ray diffraction or by differential scanning calorimetry. PMID:24350659

  16. Towards environmentally friendly Na-ion batteries: Moisture and water stability of Na2Ti3O7

    NASA Astrophysics Data System (ADS)

    Zarrabeitia, M.; Castillo-Martínez, E.; López Del Amo, J. M.; Eguía-Barrio, A.; Muñoz-Márquez, M. A.; Rojo, T.; Casas-Cabanas, M.

    2016-08-01

    We report here on the moisture and water stability of the promising Na-ion anode material Na2Ti3O7. Spontaneous Na+/H+ exchange is detected by PXRD after air exposure, forming solid solution compounds of the form Na2-xHxTi3O7 (0 < x < 2). By controlled ion exchange in aqueous solution two mixed compositions are prepared and their composition and structure are characterized with a panel of techniques. Both mixed compositions crystallize in C2/m space group like H2Ti3O7, and therefore Na+/H+ exchange is found to involve a structural transition from AA stacking of [TiO6] layers to AB stacking sequence. The electrochemical behaviour of the mixed compositions vs. Na+/Na is studied as well as that of an electrode of pure Na2Ti3O7 prepared in water media. The water-processed electrode is shown to exhibit a superior cycling stability and therefore the results obtained highlight the potential of Na2Ti3O7 as a green, low cost anode material for NIBs.

  17. Estimating the hydrogen ion concentration in concentrated NaCl and Na{sub 2}SO{sub 4} electrolytes

    SciTech Connect

    Rai, D.; Felmy, A.R.; Juracich, S.P.; Rao, F.

    1995-06-01

    Combination glass electrodes were tested for determining H{sup +} concentrations in concentrated pure and mixed NaCl and Na{sub 2}SO{sub 4} solutions, as well as natural brine systems. NaCl, Na{sub 2}SO{sub 4}, and mixtures of NaCl and Na{sub 2}SO{sub 4} solutions were analyzed. Correction factors for estimating pC{sub H}{sup +} (negative logarithm of H{sup +} concentration) were determined from measured/observed pH values. Required Gran-type titrations were done with HCl and/or NaOH. The titration method is described and a step-by-step procedure provided; it has been used previously for determining pC{sub H}{sup +} values of synthetic chloride-dominated brines. Precautions are required to determine correction factors for electrolytes that react with H{sup +} or OH{sup {minus}} [sulfate brines for titration with acid; magnesium brines for titration with base because of precipitation of Mg(OH)2]. Correction factors A (pC{sub H}{sup +} = pH{sub ob} + A) from HCl titrations were similar to those from NaOH titrations where the concentration of free H{sup +} was calculated using a thermodynamic model. These values should be applicable to solns with a very large range in measured pH values (2 to 12). Because a large number of solns were titrated with HCl and the A values are similar for HCl and NaOH titrations, the A values for NaCl and Na2SO4 solns were fit as a function of molality to allow extrapolation. For NaCl solns 0 to 6.0 M, A can be obtained by multiplying the molality by 0.159. For Na2SO4 solns 0 to 2.0 M, the values of A can be obtained from (0.221 {minus} 0.549X + 0.201X{sup 2}), where X is the molality of Na{sub 2}SO{sub 4}. Orion-Ross electrode evaluations indicated that the A values did not differ significantly for different electrodes. Results suggest that the data in this report can be used to estimate A values for different NaCl and Na{sub 2}SO{sub 4} solns even for noncalibrated electrodes.

  18. Towards environmentally friendly Na-ion batteries: Moisture and water stability of Na2Ti3O7

    NASA Astrophysics Data System (ADS)

    Zarrabeitia, M.; Castillo-Martínez, E.; López Del Amo, J. M.; Eguía-Barrio, A.; Muñoz-Márquez, M. A.; Rojo, T.; Casas-Cabanas, M.

    2016-08-01

    We report here on the moisture and water stability of the promising Na-ion anode material Na2Ti3O7. Spontaneous Na+/H+ exchange is detected by PXRD after air exposure, forming solid solution compounds of the form Na2-xHxTi3O7 (0 < x < 2). By controlled ion exchange in aqueous solution two mixed compositions are prepared and their composition and structure are characterized with a panel of techniques. Both mixed compositions crystallize in C2/m space group like H2Ti3O7, and therefore Na+/H+ exchange is found to involve a structural transition from AA stacking of [TiO6] layers to AB stacking sequence. The electrochemical behaviour of the mixed compositions vs. Na+/Na is studied as well as that of an electrode of pure Na2Ti3O7 prepared in water media. The water-processed electrode is shown to exhibit a superior cycling stability and therefore the results obtained highlight the potential of Na2Ti3O7 as a green, low cost anode material for NIBs.

  19. Central role of the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) in sodium bioenergetics of Vibrio cholerae.

    PubMed

    Steuber, Julia; Halang, Petra; Vorburger, Thomas; Steffen, Wojtek; Vohl, Georg; Fritz, Günter

    2014-12-01

    Vibrio cholerae is a Gram-negative bacterium that lives in brackish or sea water environments. Strains of V. cholerae carrying the pathogenicity islands infect the human gut and cause the fatal disease cholera. Vibrio cholerae maintains a Na(+) gradient at its cytoplasmic membrane that drives substrate uptake, motility, and efflux of antibiotics. Here, we summarize the major Na(+)-dependent transport processes and describe the central role of the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR), a primary Na(+) pump, in maintaining a Na(+)-motive force. The Na(+)-NQR is a membrane protein complex with a mass of about 220 kDa that couples the exergonic oxidation of NADH to the transport of Na(+) across the cytoplasmic membrane. We describe the molecular architecture of this respiratory complex and summarize the findings how electron transport might be coupled to Na(+)-translocation. Moreover, recent advances in the determination of the three-dimensional structure of this complex are reported.

  20. Synthesis of NaYF4 and NaLuF4 Based Upconversion Nanocrystals and Comparison of Their Properties.

    PubMed

    Ouyang, Juan; Yin, Dongguang; Song, Kailin; Wang, Chengcheng; Liu, Bing; Wu, Minghong

    2015-04-01

    In this study, four kinds of upconversion nanocrystals (UCNs) have been successfully synthesized by a facile solvothermal method. The morphology, crystalline phase, composition, grain size, upconversion luminescence and cell image of the UCNs were investigated. The properties of the NaLuF4-based UCNs were compared with the counterparts of NaYF4-based UCNs. It is found that the NaLuF4-based UCNs are apt to form hexagonal phase structures, while NaYF4-based UCNs of NaYF4:Yb, Er and NaYF4:Gd, Yb, Er are cubic and hexagonal phases respectively. The upconversion emission intensities of the NaLuF4-based UCNs are higher than that of NaYF4-based UCNs, and Gd3+ presented UCNs are higher than that of Gd3+ absented UCNs. The bioimaging application of NaLuF4:Gd, Yb, Er shows that bright upconversion luminescence can be observed when UCNs-labeled HeLa cells are excited with 980 nm light. PMID:26353495

  1. Synthesis of NaYF4 and NaLuF4 Based Upconversion Nanocrystals and Comparison of Their Properties.

    PubMed

    Ouyang, Juan; Yin, Dongguang; Song, Kailin; Wang, Chengcheng; Liu, Bing; Wu, Minghong

    2015-04-01

    In this study, four kinds of upconversion nanocrystals (UCNs) have been successfully synthesized by a facile solvothermal method. The morphology, crystalline phase, composition, grain size, upconversion luminescence and cell image of the UCNs were investigated. The properties of the NaLuF4-based UCNs were compared with the counterparts of NaYF4-based UCNs. It is found that the NaLuF4-based UCNs are apt to form hexagonal phase structures, while NaYF4-based UCNs of NaYF4:Yb, Er and NaYF4:Gd, Yb, Er are cubic and hexagonal phases respectively. The upconversion emission intensities of the NaLuF4-based UCNs are higher than that of NaYF4-based UCNs, and Gd3+ presented UCNs are higher than that of Gd3+ absented UCNs. The bioimaging application of NaLuF4:Gd, Yb, Er shows that bright upconversion luminescence can be observed when UCNs-labeled HeLa cells are excited with 980 nm light.

  2. Background study of NaI(Tl) crystals for the KIMS-NaI experiment

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; Adhikari, G.; Choi, S.; Ha, C.; Hahn, I. S.; Jeon, EJ; Joo, H. W.; Kang, W. G.; Kim, H. J.; Kim, H. O.; Kim, K. W.; Kim, N. Y.; Kim, S. K.; Kim, Y. D.; Kim, Y. H.; Lee, H. S.; Lee, J. H.; Lee, M. H.; Leonard, D. S.; Li, J.; Oh, S. Y.; Olsen, S. L.; Park, H. K.; Park, H. S.; Park, K. S.; So, J. H.; Yoon, Y. S.

    2016-05-01

    The DAMA experiment has reported an annual-modulation signal in an array of low-background NaI(Tl) scintillating crystals that may be caused by WIMP-nucleon interactions. However, to date there has been no direct confirmation of this result that uses the same taget nuclides. The Korea Invisible Mass Search (KIMS) collaboration has been engaged in an extensive R&D program to grow ultra-low background NaI(Tl) crystals for use as a direct test of the DAMA result using same nuclide targets. Six crystals were grown from different powders in order to understand mechanisms of internal background contaminations and to reduce their effects. Studies of internal backgrounds in these crystals were performed with the ultimate goal of reducing internal background contamination levels to 1 dru at 2 keV.

  3. Kinetics and stoichiometry of coupled Na efflux and Ca influx (Na/Ca exchange) in barnacle muscle cells

    PubMed Central

    1989-01-01

    Coupled Na+ exit/Ca2+ entry (Na/Ca exchange operating in the Ca2+ influx mode) was studied in giant barnacle muscle cells by measuring 22Na+ efflux and 45Ca2+ influx in internally perfused, ATP-fueled cells in which the Na+ pump was poisoned by 0.1 mM ouabain. Internal free Ca2+, [Ca2+]i, was controlled with a Ca-EGTA buffering system containing 8 mM EGTA and varying amounts of Ca2+. Ca2+ sequestration in internal stores was inhibited with caffeine and a mitochondrial uncoupler (FCCP). To maximize conditions for Ca2+ influx mode Na/Ca exchange, and to eliminate tracer Na/Na exchange, all of the external Na+ in the standard Na+ sea water (NaSW) was replaced by Tris or Li+ (Tris-SW or LiSW, respectively). In both Na-free solutions an external Ca2+ (Cao)-dependent Na+ efflux was observed when [Ca2+]i was increased above 10(-8) M; this efflux was half-maximally activated by [Ca2+]i = 0.3 microM (LiSW) to 0.7 microM (Tris-SW). The Cao-dependent Na+ efflux was half-maximally activated by [Ca2+]o = 2.0 mM in LiSW and 7.2 mM in Tris-SW; at saturating [Ca2+]o, [Ca2+]i, and [Na+]i the maximal (calculated) Cao-dependent Na+ efflux was approximately 75 pmol#cm2.s. This efflux was inhibited by external Na+ and La3+ with IC50's of approximately 125 and 0.4 mM, respectively. A Nai-dependent Ca2+ influx was also observed in Tris-SW. This Ca2+ influx also required [Ca2+]i greater than 10(-8) M. Internal Ca2+ activated a Nai-independent Ca2+ influx from LiSW (tracer Ca/Ca exchange), but in Tris-SW virtually all of the Cai-activated Ca2+ influx was Nai-dependent (Na/Ca exchange). Half-maximal activation was observed with [Na+]i = 30 mM. The fact that internal Ca2+ activates both a Cao-dependent Na+ efflux and a Nai- dependent Ca2+ influx in Tris-SW implies that these two fluxes are coupled; the activating (intracellular) Ca2+ does not appear to be transported by the exchanger. The maximal (calculated) Nai-dependent Ca2+ influx was -25 pmol/cm2.s. At various [Na+]i between 6 and 106 m

  4. North America and South America (NA-SA) neuropathy project.

    PubMed

    Pasnoor, Mamatha; Nascimento, Osvaldo J M; Trivedi, Jaya; Wolfe, Gil I; Nations, Sharon; Herbelin, Laura; de Freitas, M G; Quintanilha, Giseli; Khan, Saud; Dimachkie, Mazen; Barohn, Richard

    2013-08-01

    Peripheral neuropathy is a common neurological disorder. There may be important differences and similarities in the diagnosis of peripheral neuropathy between North America (NA) and South America (SA). Neuromuscular databases were searched for neuropathy diagnosis at two North American sites, University of Kansas Medical Center and University of Texas Southwestern Medical Center, and one South American site, Federal Fluminense University in Brazil. All patients were included into one of the six major categories: immune-mediated, diabetic, hereditary, infectious/inflammatory, systemic/metabolic/toxic (not diabetic) and cryptogenic. A comparison of the number of patients in each category was made between North America and South America databases. Total number of cases in North America was 1090 and in South America was 1034 [immune-mediated: NA 215 (19.7%), SA 191 (18%); diabetic: NA 148 (13.5%), SA 236 (23%); hereditary: NA 292 (26.7%), SA 103 (10%); infectious/inflammatory: NA 53 (4.8%), SA 141 (14%); systemic/metabolic/toxic: NA 71 (6.5%), SA 124 (12%); cryptogenic: NA 311 (28.5%), SA 239 (23%)]. Some specific neuropathy comparisons were hereditary neuropathies [Charcot-Marie-Tooth (CMT) cases] in NA 246/292 (84.2%) and SA 60/103 (58%); familial amyloid neuropathy in SA 31/103 (30%) and none in NA. Among infectious neuropathies, cases of human T-lymphotropic virus type 1 (HTLV-1) neuropathy in SA were 36/141(25%), Chagas disease in SA were 13/141(9%) and none for either in NA; cases of neuropathy due to leprosy in NA were 26/53 (49%) and in SA were 39/141(28%). South American tertiary care centers are more likely to see patients with infectious, diabetic and hereditary disorders such as familial amyloid neuropathies. North American tertiary centers are more likely to see patients with CMT. Immune neuropathies and cryptogenic neuropathies were seen equally in North America and South America.

  5. 33 CFR 147.833 - Na Kika FDS safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description....

  6. 33 CFR 147.833 - Na Kika FDS safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description....

  7. Transepithelial Na+ transport and the intracellular fluids: a computer study.

    PubMed

    Civan, M M; Bookman, R J

    1982-01-01

    Computer simulations of tight epithelia under three experimental conditions have been carried out, using the rheogenic nonlinear model of Lew, Ferreira and Moura (Proc. Roy. Soc. London. B 206:53-83, 1979) based largely on the formulation of Koefoed-Johnsen and Ussing (Acta Physiol. Scand. 42: 298-308. 1958). First, analysis of the transition between the short-circuited and open-circuited states has indicated that (i) apical Cl- permeability is a critical parameter requiring experimental definition in order to analyze cell volume regulation, and (ii) contrary to certain experimental reports, intracellular Na+ concentration (ccNa) is expected to be a strong function of transepithelial clamping voltage. Second, analysis of the effects of lowering serosal K+ concentration (csK) indicates that the basic model cannot simulate several well-documented observations; these defects can be overcome, at least qualitatively, by modifying the model to take account of the negative feedback interaction likely to exist between the apical Na+ permeability and ccNa. Third, analysis of the strongly supports the concept that osmotically induced permeability changes in the apical intercellular junctions play a physiological role in conserving the body's stores of NaCl. The analyses also demonstrate that the importance of Na+ entry across the basolateral membrane is strongly dependent upon transepithelial potential, cmNa and csK; under certain conditions, net Na+ entry could be appreciably greater across the basolateral than across the apical membrane.

  8. Adaptation of Tobacco Cells to NaCl 1

    PubMed Central

    Binzel, Marla L.; Hasegawa, Paul M.; Handa, Avtar K.; Bressan, Ray A.

    1985-01-01

    Cell lines of tobacco (Nicotiana tabacum L. var Wisconsin 38) were obtained which are adapted to grow in media with varying concentrations of NaCl, up to 35 grams per liter (599 millimolar). Salt-adapted cells exhibited enhanced abilities to gain both fresh and dry weight in the presence of NaCl compared to cells which were growing in medium without NaCl (unadapted cells). Tolerance of unadapted cells and cells adapted to 10 grams per liter NaCl was influenced by the stage of growth, with the highest degree of tolerance exhibited by cells in the exponential phase. Cell osmotic potential and turgor varied through the growth cycle of unadapted cells and cells at all levels of adaptation, with maximum turgor occurring at approximately the onset of exponential fresh weight accumulation. Adaptation to NaCl led to reduced cell expansion and fresh weight gain, while dry weight gain remained unaffected. This reduction in cell expansion was not due to failure of the cells to maintain turgor since cells adapted to NaCl underwent osmotic adjustment in excess of the change in water potential caused by the addition of NaCl to the medium. Tolerance of the adapted cells, as indicated by fresh or dry weight gain, did not increase proportionately with the increase in turgor. Adaptation of these glycophytic cells to NaCl appears to involve mechanisms which result in an altered relationship between turgor and cell expansion. Images Fig. 3 PMID:16664356

  9. The pea gene NA encodes ent-kaurenoic acid oxidase.

    PubMed

    Davidson, Sandra E; Elliott, Robert C; Helliwell, Chris A; Poole, Andrew T; Reid, James B

    2003-01-01

    The gibberellin (GA)-deficient dwarf na mutant in pea (Pisum sativum) has severely reduced internode elongation, reduced root growth, and decreased leaflet size. However, the seeds develop normally. Two genes, PsKAO1 and PsKAO2, encoding cytochrome P450 monooxygenases of the subfamily CYP88A were isolated. Both PsKAO1 and PsKAO2 had ent-kaurenoic acid oxidase (KAO) activity, catalyzing the three steps of the GA biosynthetic pathway from ent-kaurenoic acid to GA(12) when expressed in yeast (Saccharomyces cerevisiae). In addition to the intermediates ent-7alpha-hydroxykaurenoic acid and GA(12)-aldehyde, some additional products of the pea KAO activity were detected, including ent-6alpha,7alpha-dihydroxykaurenoic acid and 7beta-hydroxykaurenolide. The NA gene encodes PsKAO1, because in two independent mutant alleles, na-1 and na-2, PsKAO1 had altered sequences and the five-base deletion in PsKAO1 associated with the na-1 allele cosegregated with the dwarf na phenotype. PsKAO1 was expressed in the stem, apical bud, leaf, pod, and root, organs in which GA levels have previously been shown to be reduced in na plants. PsKAO2 was expressed only in seeds and this may explain the normal seed development and normal GA biosynthesis in seeds of na plants.

  10. Direct Measurement of {sup 21}Na+{alpha} Stellar Reaction

    SciTech Connect

    Binh, D. N.; Kubono, S.; Yamaguchi, H.; Hayakawa, S.; Hashimoto, T.; Kahl, D.; Teranishi, T.; Iwasa, N.; Kume, N.; Kato, S.; Khiem, L. H.; Tho, N. T.; Wakabayashi, Y.

    2010-08-12

    The measurement of the resonant alpha scattering and the {sup 21}Na({alpha}, p) reaction were performed for the first time in inverse kinematics with the thick target method using a {sup 21}Na radioisotope (RI) beam. This paper reports the current result of alpha scattering measurement and its astrophysics implication.

  11. Moderate temperature rechargeable NaNiS2 cells

    NASA Technical Reports Server (NTRS)

    Abraham, K. M.

    1983-01-01

    A rechargeable sodium battery of the configuration, liquid Na/beta double prime -Al2O3/molten NaAlCl4, NiS2, operating in the temperature range of 170 to 190 C, is described. This battery is capable of delivering or = to 50 W-hr/1b and 1000 deep discharge/charge cycles.

  12. Molecular Mechanisms of Bone 18F-NaF Deposition

    PubMed Central

    Czernin, Johannes; Satyamurthy, Nagichettiar; Schiepers, Christiaan

    2011-01-01

    There is renewed interest in 18F-NaF bone imaging with PET or PET/CT. The current brief discussion focuses on the molecular mechanisms of 18F-NaF deposition in bone and presents model-based approaches to quantifying bone perfusion and metabolism in the context of preclinical and clinical applications of bone imaging with PET. PMID:21078790

  13. Naïve Bayes classification in R

    PubMed Central

    2016-01-01

    Naïve Bayes classification is a kind of simple probabilistic classification methods based on Bayes’ theorem with the assumption of independence between features. The model is trained on training dataset to make predictions by predict() function. This article introduces two functions naiveBayes() and train() for the performance of Naïve Bayes classification. PMID:27429967

  14. Unidirectional Flux Balance of Monovalent Ions in Cells with Na/Na and Li/Na Exchange: Experimental and Computational Studies on Lymphoid U937 Cells

    PubMed Central

    Vereninov, Igor A.; Yurinskaya, Valentina E.; Model, Michael A.; Vereninov, Alexey A.

    2016-01-01

    Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1–10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential. PMID:27159324

  15. Extending 3-Frequency Na Doppler Lidar Wind and Temperature Measurements into Lower Atmosphere with Na Double-Edge Magneto-Optic Filters (Na-DEMOF)

    NASA Astrophysics Data System (ADS)

    Huang, W.; Chu, X.; Wiig, J.; Williams, B. P.; Harrell, S.; She, C.

    2008-12-01

    An important atmospheric process is the wave coupling among different layers. It is crucial to trace waves from their source regions in the lower atmosphere to their dissipation regions in the middle and upper atmosphere. This requires the profiling of wind and temperature simultaneously from the lower to the upper atmosphere. Utilizing Doppler shift and Doppler broadening effects, various types of Doppler lidars can measure wind and temperature in different atmospheric regions. However, none of the single lidars is able to profile both variables throughout the atmosphere. Resonance fluorescence Na Doppler lidars measure wind and temperature simultaneously in the mesosphere and lower thermosphere. They have made significant contributions to the study of wave dynamics. Unfortunately, their measurements are limited to 80-105 km where the trace gas Na atoms are available. We proposed to incorporate a Na double-edge magneto-optic filter (Na-DEMOF) into the receiver of a 3-frequency Na Doppler lidar to extend its wind and temperature measurements into the lower atmosphere. Two prototypes based on cold- and hot-cell designs were constructed and characterized with laboratory tests. The hot-cell filter showed superior performances than the cold-cell containing buffer gas. The hot-cell Na-DEMOF was also successfully modeled by quantum mechanics calculations. Lidar simulations were conducted for analysis of measurement errors in the altitude range of 15-50 km with the hot-cell filter developed. Field test using the hot-cell Na-DEMOF with the Colorado State University Na lidar is under its way and the initial results will be reported and compared to lidar simulation.

  16. Unidirectional Flux Balance of Monovalent Ions in Cells with Na/Na and Li/Na Exchange: Experimental and Computational Studies on Lymphoid U937 Cells.

    PubMed

    Vereninov, Igor A; Yurinskaya, Valentina E; Model, Michael A; Vereninov, Alexey A

    2016-01-01

    Monovalent ion traffic across the cell membrane occurs via various pathways. Evaluation of individual fluxes in whole cell is hampered by their strong interdependence. This difficulty can be overcome by computational analysis of the whole cell flux balance. However, the previous computational studies disregarded ion movement of the self-exchange type. We have taken this exchange into account. The developed software allows determination of unidirectional fluxes of all monovalent ions via the major pathways both under the balanced state and during transient processes. We show how the problem of finding the rate coefficients can be solved by measurement of monovalent ion concentrations and some of the fluxes. Interdependence of fluxes due to the mandatory conditions of electroneutrality and osmotic balance and due to specific effects can be discriminated, enabling one to identify specific changes in ion transfer machinery under varied conditions. To test the effectiveness of the developed approach we made use of the fact that Li/Na exchange is known to be an analogue of the coupled Na/Na exchange. Thus, we compared the predicted and experimental data obtained on U937 cells under varied Li+ concentrations and following inhibition of the sodium pump with ouabain. We found that the coupled Na/Na exchange in U937 cells comprises a significant portion of the entire Na+ turnover. The data showed that the loading of the sodium pump by Li/Na exchange involved in the secondary active Li+ transport at 1-10 mM external Li+ is small. This result may be extrapolated to similar Li+ and Na+ flux relationships in erythrocytes and other cells in patients treated with Li+ in therapeutic doses. The developed computational approach is applicable for studying various cells and can be useful in education for demonstrating the effects of individual transporters and channels on ion gradients, cell water content and membrane potential. PMID:27159324

  17. Feasibility study for a secondary Na/S battery

    NASA Technical Reports Server (NTRS)

    Abraham, K. M.; Schiff, R.; Brummer, S. B.

    1979-01-01

    The feasibility of a moderate temperature Na battery was studied. This battery is to operate at a temperature in the range of 100-150 C. Two kinds of cathode were investigated: (1) a soluble S cathode consisting of a solution of Na2Sn in an organic solvent and (2) an insoluble S cathode consisting of a transition metal dichalcogenide in contact with a Na(+)ion conducting electrolyte. Four amide solvents, dimethyl acetamide, diethyl acetamide, N-methyl acetamide and acetamide, were investigated as possible solvents for the soluble S cathode. Results of stability and electrochemical studies using these solvents are presented. The dialkyl substituted amides were found to be superior. Although the alcohol 1,3-cyclohexanediol was found to be stable in the presence of Na2Sn at 130 C, its Na2Sn solutions did not appear to have suitable electrochemical properties.

  18. Trisodium citrate, Na3(C6H5O7)

    PubMed Central

    Rammohan, Alagappa; Kaduk, James A.

    2016-01-01

    The crystal structure of anhydrous tris­odium citrate, Na3(C6H5O7), has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory (DFT). There are two independent five-coordinate Na+ and one six-coordinate Na+ cations in the asymmetric unit. The [NaO5] and [NaO6] polyhedra share edges and corners to form a three-dimensional framework. There are channels parallel to the a and b axes in which the remainder of the citrate anions reside. The only hydrogen bonds are an intra­molecular one between the hy­droxy group and one of the terminal carboxyl­ate O atoms and an intermolecular one between a methylene group and the hydroxyl O atom. PMID:27308044

  19. NaCl-induced accelerated oxidation of chromium

    SciTech Connect

    Shinata, Y.; Nishi, Y.

    1986-10-01

    This paper describes new phenomena about chloride-induced ;accelerated oxidation of chromium. Thermal analysis was adopted to examine the oxidation, which was studied particularly in the case of NaCl. The presence of NaCl remarkably accelerates the oxidation of chromium. The process occurs below the melting point of NaCl, and the main reaction product is Cr/sub 2/O/sub 3/. In the accelerated oxidation NaCl plays a catalytic role because it is not consumed significantly in the process. DTA analysis reveals that the heat of reaction also accelerates the rate of oxidation, especially at an early stage of the reaction. The accelerated oxidation takes place similarly under the presence of chlorides other than NaCl, but the oxidation rate depends on the kind of salt. Therefore the Cl/sup -/ anion plays an important role in the process, while the nature of the cation affects the rate of acceleration.

  20. DIANA NaI-Detector Energy Calibration

    NASA Astrophysics Data System (ADS)

    O'Connor, Kyle; Elofson, David; Lewis, Codie; O'Brien, Erin; Buggelli, Kelsey; Miller, Nevin; O'Rielly, Grant; Maxtagg Collaboration

    2014-09-01

    The DIANA detector is being used for measurements of near threshold pion photoproduction and high-energy nuclear Compton scattering being performed at the MAX-lab tagged photon facility in Lund, Sweden. Accurate energy calibrations are essential for determining the final results from both of these experiments. An energy calibration has been performed for DIANA, a single-crystal, large-volume, NaI detector. This calibration was made by placing the detector directly in the tagged photon beam with energies from 145 to 165 MeV and fitting the detector response to the known photon energies. The DIANA crystal is instrumented with 19 PMTs, pedestal corrections were applied and the PMTs were gain matched in order to combine the readout value from each PMT and determine the final detector response. This response was fitted to the tagged photon energies to provide the final energy calibration. The calibrations were performed with two triggers; one from the detector itself and one provided by the photon tagger. The quality of the final calibration fit and the energy resolution of the detector, σ ~ 2 . 4 MeV, will be shown.

  1. Endurance testing with Li/Na electrolyte

    SciTech Connect

    Ong, E.T.; Remick, R.J.; Sishtla, C.I.

    1996-12-31

    The Institute of Gas Technology (IGT), under subcontract to M-C Power Corporation under DOE funding, has been operating bench-scale fuel cells to investigate the performance and endurance issues of the Li/Na electrolyte because it offers higher ionic conductivity, higher exchange current densities, lower vapor pressures, and lower cathode dissolution rates than the Li/K electrolyte. These cells have continued to show higher performance and lower decay rates than the Li/K cells since the publication of our two previous papers in 1994. In this paper, test results of two long-term 100-cm{sup 2} bench scale cells are discussed. One cell operated continuously at 160 mA/cm{sup 2} for 17,000 hours with reference gases (60H{sub 2}/20CO{sub 2}/20H{sub 2}O fuel at 75% utilization and 30CO{sub 2}/70 air oxidant humidified at room temperature at 50% utilization). The other cell operated at 160 mA/cm{sup 2} for 6900 hours at 3 atm with system gases (64H{sub 2}/16CO{sub 2}/20H{sub 2}O at 75% utilization and an M-C Power system-defined oxidant at 40% utilization). Both cells have shown the highest performance and longest endurance among IGT cells operated to date.

  2. Genome Sequences of Cupriavidus metallidurans Strains NA1, NA4, and NE12, Isolated from Space Equipment

    PubMed Central

    Monsieurs, Pieter; Mijnendonckx, Kristel; Provoost, Ann; Venkateswaran, Kasthuri; Ott, C. Mark; Leys, Natalie

    2014-01-01

    Cupriavidus metallidurans NA1, NA4, and NE12 were isolated from space and spacecraft-associated environments. Here, we report their draft genome sequences with the aim of gaining insight into their potential to adapt to these environments. PMID:25059868

  3. Production of Secondary Radioactive 21Na Beam for the Study of 21Na(α,p)24Mg Stellar Reaction

    NASA Astrophysics Data System (ADS)

    Binh, Dam Nguyen; Khiem, Le Hong; Kubono, S.; Yamaguchi, H.; Wakabayashi, Y.; Hayakawa, S.; Kim, A.

    2008-04-01

    The availability of radioactive beams has produced great opportunities for advances in our understanding of the nucleosynthesis occurring in stellar explosions such as novae, X-ray burst and supernovae. By using an in-flight low-energy radioisotope beam separator (CRIB) at Center for Nuclear Study (CNS), University of Tokyo, we have successfully produced the 21Na proton-rich beam for the study of 21Na(α,p)24Mg reaction which is related to the astrophysically important production of 22Na in the stellar explosive environments. Since it is the first time when this reaction is studied experimentally, we have performed a test experiment to produce the 21Na beam and to estimate the feasibility of the experimental study of 21Na(α,p)24Mg reaction.

  4. Brefeldin A inhibition of apical Na+ channels in epithelia.

    PubMed

    Fisher, R S; Grillo, F G; Sariban-Sohraby, S

    1996-01-01

    Brefeldin A (BFA) is used to probe trafficking of proteins through the central vacuolar system (CVS) in a variety of cells. Transepithelial Na+ transport by high-resistance epithelia, such as A6 cultured cells, is inhibited by BFA. Apical Na+ channels, as well as basolateral pumps and K+ channels, are complex proteins that probably traverse the CVS for routing to the plasma membrane. BFA (5 micrograms/ml) decreases transepithelial Na+ current near zero and increases resistance reversibly after 4 h. Longer exposures are toxic. When tissues were treated for 20 h with 0.2 microgram/ml BFA, Na+ transport also was reversibly inhibited. Using noise analysis, we found that BFA drastically reduced apical Na+ channel density. The increase in single channel current was consistent with cell hyperpolarization. After apical permeabilization with nystatin, changes in transepithelial current reflect changes in basolateral membrane transport. Transport at this membrane was inhibited by ouabain and cycloheximide, but not by BFA. After BFA, aldosterone was ineffective, suggesting that an intact CVS is required for stimulation by this hormone. Thus BFA inhibition of Na+ transport is localized at the apical membrane. Implications for channel turnover as a mechanism for regulating the Na+ transport rate are discussed.

  5. Hormonal regulation of Na -K -ATPase in cultured epithelial cells

    SciTech Connect

    Johnson, J.P.; Jones, D.; Wiesmann, W.P.

    1986-08-01

    Aldosterone and insulin stimulate Na transport through mechanisms involving protein synthesis. Na -K -ATPase has been implicated in the action of both hormones. The authors examined the effect of aldosterone and insulin on Na -K -ATPase in epithelial cells in culture derived from toad urinary bladder (TB6C) and toad kidney (A6). Aldosterone, but not insulin, increases short-circuit current (I/sub sc/) in TB6C cells. Aldosterone increases Na -K -(TSP)ATPase activity after 18 h of incubation, but no effect can be seen at 3 and 6 h. Amiloride, which inhibits aldosterone-induced increases in I/sub sc/, has no effect on either basal or aldosterone stimulated enzyme activity. Both aldosterone and insulin increase I/sub sc/ in A6 cells and when added together are synergistic. Aldosterone stimulates enzyme activity in A6 cells, but insulin alone has no effect. However, aldosterone and insulin together stimulate enzyme activity more than aldosterone alone. It appears that stimulation of Na -K -ATPase activity is involved in aldosterone action in both cell lines but does not appear to be due to increased Na entry, since enhanced enzyme activity is not inhibited by amiloride. In contrast, insulin alone has no direct effect on Na -K -ATPase, although the increased enzyme activity following both agents in combination may explain their synergism on I/sub sc/.

  6. Rat hepatocytes exhibit basolateral Na+/HCO/sub 3/- cotransport

    SciTech Connect

    Renner, E.L.; Lake, J.R.; Scharschmidt, B.F.; Zimmerli, B.; Meier, P.J.

    1989-04-01

    Primary cultures and plasma membrane vesicles were used to characterize Na+ and HCO3- transport by rat hepatocytes. Na+ uptake into hepatocytes was stimulated approximately 10-fold by 25 mM extracellular HCO3-.HCO3--stimulated Na+ uptake was saturable, abolished by 4-acetamido-4'-isothiocyano-2,2'-disulfonic acid stilbene (SITS), and unaffected by amiloride or Cl- removal. Neither propionate nor acetate reproduced this effect of HCO3-. 22Na efflux from preloaded hepatocytes was similarly increased approximately 10-fold by an in greater than out HCO3- concentration gradient. 22Na efflux was also increased by valinomycin and an in greater than out K+ concentration gradient in the presence but not absence of HCO3-. Intracellular pH (pHi) measured with the pH-sensitive fluorochrome 2',7'-bis-(2-carboxyethyl)-5-(and 6-)carboxyfluorescein (BCECF) decreased at a rate of 0.227 (+/- 0.074 SEM) pH units/min when extracellular HCO3- concentration was lowered from 25 to 5 mM at constant PCO2. This intracellular acidification rate was decreased 50-60% in the absence of Na+ or presence of SITS, and was unaffected by amiloride or Cl- removal. Membrane hyperpolarization produced by valinomycin and an in greater than out K+ concentration gradient caused pHi to fall; the rate of fall was decreased 50-70% by Na+ removal or SITS, but not amiloride. An inside positive K+ diffusion potential and a simultaneous out greater than in HCO3- gradient produced a transient 4,4'-diisothiocyano-2,2' disulfonic acid stilbene (DIDS) sensitive, amiloride-insensitive 22Na accumulation in basolateral but not canalicular membrane vesicles. Rat hepatocytes thus exhibit electrogenic basolateral Na+/HCO3- cotransport.

  7. Five Board Games for the Language Classroom: Uvas, Montana Rusa, El Futbol, La Corrida de Verbos, Paso a Paso.

    ERIC Educational Resources Information Center

    Snyder, Barbara

    A collection of five board games for the Spanish language classroom contains gameboards, game markers, and directions for each game. It also contains general instructions for the teacher about the classroom use of board games. The games include: "Uvas," for use in vocabulary development and cultural awareness; "Montana Rusa," for general…

  8. Phyla- and Subtype-Selectivity of CgNa, a Na+ Channel Toxin from the Venom of the Giant Caribbean Sea Anemone Condylactis Gigantea

    PubMed Central

    Billen, Bert; Debaveye, Sarah; Béress, Lászlo; Tytgat, Jan

    2010-01-01

    Because of their prominent role in electro-excitability, voltage-gated sodium (NaV) channels have become the foremost important target of animal toxins. These toxins have developed the ability to discriminate between closely related NaV subtypes, making them powerful tools to study NaV channel function and structure. CgNa is a 47-amino acid residue type I toxin isolated from the venom of the Giant Caribbean Sea Anemone Condylactis gigantea. Previous studies showed that this toxin slows the fast inactivation of tetrodotoxin-sensitive NaV currents in rat dorsal root ganglion neurons. To illuminate the underlying NaV subtype-selectivity pattern, we have assayed the effects of CgNa on a broad range of mammalian isoforms (NaV1.2–NaV1.8) expressed in Xenopus oocytes. This study demonstrates that CgNa selectively slows the fast inactivation of rNaV1.3/β1, mNaV1.6/β1 and, to a lesser extent, hNaV1.5/β1, while the other mammalian isoforms remain unaffected. Importantly, CgNa was also examined on the insect sodium channel DmNaV1/tipE, revealing a clear phyla-selectivity in the efficacious actions of the toxin. CgNa strongly inhibits the inactivation of the insect NaV channel, resulting in a dramatic increase in peak current amplitude and complete removal of fast and steady-state inactivation. Together with the previously determined solution structure, the subtype-selective effects revealed in this study make of CgNa an interesting pharmacological probe to investigate the functional role of specific NaV channel subtypes. Moreover, further structural studies could provide important information on the molecular mechanism of NaV channel inactivation. PMID:21833172

  9. Contributions of cellular leak pathways to net NaHCO3 and NaCl absorption.

    PubMed Central

    Preisig, P A; Alpern, R J

    1989-01-01

    Proton and formic acid permeabilities were measured in the in vivo microperfused rat proximal convoluted tubule by examining the effect on intracellular pH when [H] and/or [formic acid] were rapidly changed in the luminal or peritubular fluids. Apical and basolateral membrane H permeabilities were 0.52 +/- 0.07 and 0.67 +/- 0.18 cm/s, respectively. Using these permeabilities we calculate that proton backleak from the luminal fluid to cell does not contribute significantly to net proton secretion in the early proximal tubule, but may contribute in the late proximal tubule. Apical and basolateral membrane formic acid permeabilities measured at extracellular pH 6.62 were 4.6 +/- 0.5 X 10(-2) and 6.8 +/- 1.5 X 10(-2) cm/s, respectively. Control studies demonstrated that the formic acid permeabilities were not underestimated by either the simultaneous movement of formate into the cell or the efflux of formic acid across the opposite membrane. The measured apical membrane formic acid permeability is too small to support all of transcellular NaCl absorption in the rat by a mechanism that involves Na/H-Cl/formate transporters operating in parallel with formic acid nonionic diffusion. PMID:2542374

  10. Structure determination in 55-atom Li-Na and Na-K nanoalloys.

    PubMed

    Aguado, Andrés; López, José M

    2010-09-01

    The structure of 55-atom Li-Na and Na-K nanoalloys is determined through combined empirical potential (EP) and density functional theory (DFT) calculations. The potential energy surface generated by the EP model is extensively sampled by using the basin hopping technique, and a wide diversity of structural motifs is reoptimized at the DFT level. A composition comparison technique is applied at the DFT level in order to make a final refinement of the global minimum structures. For dilute concentrations of one of the alkali atoms, the structure of the pure metal cluster, namely, a perfect Mackay icosahedron, remains stable, with the minority component atoms entering the host cluster as substitutional impurities. At intermediate concentrations, the nanoalloys adopt instead a core-shell polyicosahedral (p-Ih) packing, where the element with smaller atomic size and larger cohesive energy segregates to the cluster core. The p-Ih structures show a marked prolate deformation, in agreement with the predictions of jelliumlike models. The electronic preference for a prolate cluster shape, which is frustrated in the 55-atom pure clusters due to the icosahedral geometrical shell closing, is therefore realized only in the 55-atom nanoalloys. An analysis of the electronic densities of states suggests that photoelectron spectroscopy would be a sufficiently sensitive technique to assess the structures of nanoalloys with fixed size and varying compositions.

  11. 23 Na and 17O NMR studies of hyperkagome Na4Ir3O8

    NASA Astrophysics Data System (ADS)

    Shockley, Abigail; Bert, Fabrice; Orain, Jean-Christophe; Okamoto, Yoshihiko; Mendels, Philippe

    2015-03-01

    Na4Ir3O8 is a unique case of a 3D corner sharing triangular lattice which can be decorated with quantum spins. It has spurred a lot of theoretical interest as a spin liquid candidate of a new kind where the Hamiltonian might not be thought in terms of a simple Heisenberg case because of spin orbit coupling on the Ir 5d element. We present a comprehensive set of NMR data taken on both the 23Na and 17O sites. We have found that magnetic freezing of all Ir sites sets in below Tf ~ 7.5K ~ 0 . 019 J with a clear hyperfine field transferred from Ir moments and a drastic decrease of 1 /T1 . Above Tf, physical properties are expected to be a landmark of frustration in this exotic geometry. We will discuss our shift and relaxation data in the temperature range of 300K to 7.5 K in the light of published thermodynamic measurements (Y. Okamotoa et al, PRL 99 137207, 2007 and Y. Singh et al, PRB 88 220413(R), 2013) and comment on their implications for the already existing large body of theoretical work.

  12. α-synuclein assemblies sequester neuronal α3-Na+/K+-ATPase and impair Na+ gradient

    PubMed Central

    Shrivastava, Amulya Nidhi; Redeker, Virginie; Fritz, Nicolas; Pieri, Laura; Almeida, Leandro G; Spolidoro, Maria; Liebmann, Thomas; Bousset, Luc; Renner, Marianne; Léna, Clément; Aperia, Anita; Melki, Ronald; Triller, Antoine

    2015-01-01

    Extracellular α-synuclein (α-syn) assemblies can be up-taken by neurons; however, their interaction with the plasma membrane and proteins has not been studied specifically. Here we demonstrate that α-syn assemblies form clusters within the plasma membrane of neurons. Using a proteomic-based approach, we identify the α3-subunit of Na+/K+-ATPase (NKA) as a cell surface partner of α-syn assemblies. The interaction strength depended on the state of α-syn, fibrils being the strongest, oligomers weak, and monomers none. Mutations within the neuron-specific α3-subunit are linked to rapid-onset dystonia Parkinsonism (RDP) and alternating hemiplegia of childhood (AHC). We show that freely diffusing α3-NKA are trapped within α-syn clusters resulting in α3-NKA redistribution and formation of larger nanoclusters. This creates regions within the plasma membrane with reduced local densities of α3-NKA, thereby decreasing the efficiency of Na+ extrusion following stimulus. Thus, interactions of α3-NKA with extracellular α-syn assemblies reduce its pumping activity as its mutations in RDP/AHC. PMID:26323479

  13. Ecotoxicological evaluation of three deicers (NaCl, NaFo, CMA)-effect on terrestrial organisms.

    PubMed

    Robidoux, P Y; Delisle, C E

    2001-02-01

    The use of chemical deicers such as sodium chloride (NaCl) has increased significantly during the past three decades. Deicers induce metal corrosion and alter the physicochemical properties of soils and water. Environmental damage caused by the use of NaCl has prompted government agencies to find alternative deicers. This article presents a comparative ecotoxicological study of three deicers on soil organisms. Sodium formiate (NaFo) and calcium-magnesium acetate (CMA) are the most interesting commercially available deicers based upon their characteristics and potential toxicity. Organisms used in this study were four species of macrophytes (cress (Lepidium sativum), barley (Ordeum vulgare), red fescue grass (Festuca rubra), Kentucky bluegrass (Poa pratensis)) and an invertebrate (Eisenia fetida). Using standardized and modified methods, the relative toxicity of deicers was CMA < NaFo congruent with NaCl. The results demonstrate that these chemicals could have similar impacts in terrestrial environments since similar quantities of NaFo and greater amounts of CMA are necessary to achieve the same efficiency as NaCl. The toxicity of the tested substances was lower in natural composted soil than in artificial substrate (silica or OECD soil), indicating decreased environmental bioavailability. The response of the organisms changed according to endpoint, species, and soil characteristics (artificial substrate as compared to natural organic soil). The most sensitive endpoint measured was macrophyte growth with Kentucky bluegrass being the most sensitive species.

  14. Robust NaO2 Electrochemistry in Aprotic Na-O2 Batteries Employing Ethereal Electrolytes with a Protic Additive.

    PubMed

    Abate, Iwnetim I; Thompson, Leslie E; Kim, Ho-Cheol; Aetukuri, Nagaphani B

    2016-06-16

    Aprotic metal-oxygen batteries, such as Li-O2 and Na-O2 batteries, are of topical research interest as high specific energy alternatives to state-of-the-art Li-ion batteries. In particular, Na-O2 batteries with NaO2 as the discharge product offer higher practical specific energy with better rechargeability and round-trip energy efficiency when compared to Li-O2 batteries. In this work, we show that the electrochemical deposition and dissolution of NaO2 in Na-O2 batteries is unperturbed by trace water impurities in Na-O2 battery electrolytes, which is desirable for practical battery applications. We find no evidence for the formation of other discharge products such as Na2O2·H2O. Furthermore, the electrochemical efficiency during charge remains near ideal in the presence of trace water in electrolytes. Although sodium anodes react with trace water leading to the formation of a high-impedance solid electrolyte interphase, the increase in discharge overpotential is only ∼100 mV when compared to cells employing nominally anhydrous electrolytes. PMID:27214400

  15. Robust NaO2 Electrochemistry in Aprotic Na-O2 Batteries Employing Ethereal Electrolytes with a Protic Additive.

    PubMed

    Abate, Iwnetim I; Thompson, Leslie E; Kim, Ho-Cheol; Aetukuri, Nagaphani B

    2016-06-16

    Aprotic metal-oxygen batteries, such as Li-O2 and Na-O2 batteries, are of topical research interest as high specific energy alternatives to state-of-the-art Li-ion batteries. In particular, Na-O2 batteries with NaO2 as the discharge product offer higher practical specific energy with better rechargeability and round-trip energy efficiency when compared to Li-O2 batteries. In this work, we show that the electrochemical deposition and dissolution of NaO2 in Na-O2 batteries is unperturbed by trace water impurities in Na-O2 battery electrolytes, which is desirable for practical battery applications. We find no evidence for the formation of other discharge products such as Na2O2·H2O. Furthermore, the electrochemical efficiency during charge remains near ideal in the presence of trace water in electrolytes. Although sodium anodes react with trace water leading to the formation of a high-impedance solid electrolyte interphase, the increase in discharge overpotential is only ∼100 mV when compared to cells employing nominally anhydrous electrolytes.

  16. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

    PubMed

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-02-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading. PMID:26652350

  17. Determinants of substrate and cation transport in the human Na+/dicarboxylate cotransporter NaDC3.

    PubMed

    Schlessinger, Avner; Sun, Nina N; Colas, Claire; Pajor, Ana M

    2014-06-13

    Metabolic intermediates, such as succinate and citrate, regulate important processes ranging from energy metabolism to fatty acid synthesis. Cytosolic concentrations of these metabolites are controlled, in part, by members of the SLC13 gene family. The molecular mechanism underlying Na(+)-coupled di- and tricarboxylate transport by this family is understood poorly. The human Na(+)/dicarboxylate cotransporter NaDC3 (SLC13A3) is found in various tissues, including the kidney, liver, and brain. In addition to citric acid cycle intermediates such as α-ketoglutarate and succinate, NaDC3 transports other compounds into cells, including N-acetyl aspartate, mercaptosuccinate, and glutathione, in keeping with its dual roles in cell nutrition and detoxification. In this study, we construct a homology structural model of NaDC3 on the basis of the structure of the Vibrio cholerae homolog vcINDY. Our computations are followed by experimental testing of the predicted NaDC3 structure and mode of interaction with various substrates. The results of this study show that the substrate and cation binding domains of NaDC3 are composed of residues in the opposing hairpin loops and unwound portions of adjacent helices. Furthermore, these results provide a possible explanation for the differential substrate specificity among dicarboxylate transporters that underpin their diverse biological roles in metabolism and detoxification. The structural model of NaDC3 provides a framework for understanding substrate selectivity and the Na(+)-coupled anion transport mechanism by the human SLC13 family and other key solute carrier transporters.

  18. Characterization and antibacterial activity of silver exchanged regenerated NaY zeolite from surfactant-modified NaY zeolite.

    PubMed

    Salim, Mashitah Mad; Malek, Nik Ahmad Nizam Nik

    2016-02-01

    The antibacterial activity of regenerated NaY zeolite (thermal treatment from cetyltrimethyl ammonium bromide (CTAB)-modified NaY zeolite and pretreatment with Na ions) loaded with silver ions were examined using the broth dilution minimum inhibitory concentration (MIC) method against Escherichia coli (E. coli ATCC 11229) and Staphylococcus aureus (S. aureus ATCC 6538). X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and chemical elemental analyses were used to characterize the regenerated NaY and AgY zeolites. The XRD patterns indicated that the calcination and addition of silver ions on regenerated NaY zeolite did not affect the structure of the regenerated NaY zeolite as the characteristic peaks of the NaY zeolite were retained, and no new peaks were observed. The regenerated AgY zeolite showed good antibacterial activity against both bacteria strains in distilled water, and the antibacterial activity of the samples increased with increasing Ag loaded on the regenerated AgY zeolite; the regenerated AgY zeolite was more effective against E. coli than S. aureus. However, the antibacterial activity of the regenerated AgY was not effective in saline solution for both bacteria. The study showed that CTAB-modified NaY zeolite materials could be regenerated to NaY zeolite using thermal treatment (550°C, 5h) and this material has excellent performance as an antibacterial agent after silver ions loading.

  19. On the structure and chemical bonding of Si62- and Si62- in NaSi6- upon Na+ coordination

    NASA Astrophysics Data System (ADS)

    Zubarev, Dmitry Yu.; Alexandrova, Anastassia N.; Boldyrev, Alexander I.; Cui, Li-Feng; Li, Xi; Wang, Lai-Sheng

    2006-03-01

    Photoelectron spectroscopy was combined with ab initio calculations to elucidate the structure and bonding in Si62- and NaSi6-. Well-resolved electronic transitions were observed in the photoelectron spectra of Si6- and NaSi6- at three photon energies (355, 266, and 193nm). The spectra of NaSi6- were observed to be similar to those of Si6- except that the electron binding energies of the former are lower, suggesting that the Si6 motif in NaSi6- is structurally and electronically similar to that in Si6-. The electron affinities of Si6 and NaSi6 were measured fairly accurately to be 2.23±0.03eV and 1.80±0.05eV, respectively. Global minimum structure searches for Si62- and NaSi6- were performed using gradient embedded genetic algorithm followed by B3LYP, MP2, and CCSD(T) calculations. Vertical electron detachment energies were calculated for the lowest Si6- and NaSi6- structures at the CCSD(T)/6-311+G(2df ), ROVGF/6-311+G(2df), UOVGF/6-311+G(2d), and time-dependent B3LYP/6-311+G(2df) levels of theory. Experimental vertical detachment energies were used to verify the global minimum structure for NaSi6-. Though the octahedral Si62-, analogous to the closo form of borane B6H62-, is the most stable form for the bare hexasilicon dianion, it is not the kernel for the NaSi6- global minimum. The most stable isomer of NaSi6- is based on a Si62- motif, which is distorted into C2v symmetry similar to the ground state structure of Si6-. The octahedral Si62- coordinated by a Na+ is a low-lying isomer and was also observed experimentally. The chemical bonding in Si62- and NaSi6- was understood using natural bond orbital, molecular orbital, and electron localization function analyses.

  20. Na double-edge magneto-optic filter for Na lidar profiling of wind and temperature in the lower atmosphere.

    PubMed

    Huang, Wentao; Chu, Xinzhao; Williams, B P; Harrell, S D; Wiig, Johannes; She, C-Y

    2009-01-15

    A Na double-edge magneto-optic filter is proposed for incorporation into the receiver of a three-frequency Na Doppler lidar to extend its wind and temperature measurements into the lower atmosphere. Two prototypes based on cold- and hot-cell designs were constructed and tested with laser scanning and quantum mechanics modeling. The hot-cell filter exhibits superior performances over the cold-cell filter containing buffer gas. Lidar simulations, metrics, and error analyses show that simultaneous wind and temperature measurements are feasible in the altitude range of 20-50 km using the hot-cell filter and reasonable Na lidar parameters. PMID:19148254

  1. Lattice sites of Na dopants in ZnO

    NASA Astrophysics Data System (ADS)

    Wahl, U.; Correia, J. G.; Amorim, L.; Decoster, S.; da Silva, M. R.; Pereira, L. M. C.

    2016-09-01

    The angular distribution of β ‑ particles emitted by the radioactive isotope 24Na was monitored following implantation into ZnO single crystals at fluences above 5 × 1012 cm‑2 at CERN’s ISOLDE facility. We identified sodium on two distinct sites: on substitutional Zn sites and on interstitial sites that are close to the so-called octahedral site. The interstitial Na was to a large extent already converted to substitutional Na for annealing at 200 °C, from which an activation energy of 0.8–1.3 eV, most likely around 1.2 eV, is estimated for the migration of interstitial Na in ZnO.

  2. Lattice sites of Na dopants in ZnO

    NASA Astrophysics Data System (ADS)

    Wahl, U.; Correia, J. G.; Amorim, L.; Decoster, S.; da Silva, M. R.; Pereira, L. M. C.

    2016-09-01

    The angular distribution of β - particles emitted by the radioactive isotope 24Na was monitored following implantation into ZnO single crystals at fluences above 5 × 1012 cm-2 at CERN’s ISOLDE facility. We identified sodium on two distinct sites: on substitutional Zn sites and on interstitial sites that are close to the so-called octahedral site. The interstitial Na was to a large extent already converted to substitutional Na for annealing at 200 °C, from which an activation energy of 0.8-1.3 eV, most likely around 1.2 eV, is estimated for the migration of interstitial Na in ZnO.

  3. Degradation Of Carbon/Phenolic Composites By NaOH

    NASA Technical Reports Server (NTRS)

    King, H. M.; Semmel, M. L.; Goldberg, B. E.; Clinton, Raymond G., Jr.

    1989-01-01

    Effects of sodium hydroxide contamination level on physical and chemical properties of phenolic resin and carbon/phenolic composites described in report. NaOH degrades both carbon and phenolic components of carbon/phenolic laminates.

  4. VIEW OF CEMETERY SECTION NA (NEW ADDITION), WITH NORTHERN PERIMETER ...

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

    VIEW OF CEMETERY SECTION NA (NEW ADDITION), WITH NORTHERN PERIMETER FENCE ALONG LINCOLN BOULEVARD IN FOREGROUND. VIEW TO SOUTH. - San Francisco National Cemetery, 1 Lincoln Boulevard, San Francisco, San Francisco County, CA

  5. VIEW OF CEMETERY SECTIONS NA (NEW ADDITION) AND NAWS (NEW ...

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

    VIEW OF CEMETERY SECTIONS NA (NEW ADDITION) AND NAWS (NEW ADDITION WEST SIDE) ALONG NORTH DRIVE, WITH MAINTENANCE COMPLEX AT LEFT BACKGROUND. VIEW TO SOUTHEAST. - San Francisco National Cemetery, 1 Lincoln Boulevard, San Francisco, San Francisco County, CA

  6. Interpretation of Na-K-Mg relations in geothermal waters

    USGS Publications Warehouse

    Fournier, R.O.

    1990-01-01

    When using a Na-K-???Mg triangular diagram as an aid in the interpretation of a geothermal water, the estimated temperature of last water-rock equilibration may change by as much as 50??C, depending on which of the many Na/K geothermometers one assumes is correct. A particular geothermometer may work well in one place and not in another because of differences in the mineralogy of the phases that are in contact with the reservoir fluid. The position of the full equilibrium line that is used for geothermometry and for assessing degrees of departure from equilibrium also changes as the assumed K/???Mg geothermometer equation changes. The degree of ambiguity can be evaluated by utilizing the results of all the recently published Na/K geothermometers on a single Na-K-???Mg triangular plot.

  7. Tb/Na tobermorite: Thermal behaviour and high temperature products

    SciTech Connect

    Garra, Walter; Marchetti, Fabio; Merlino, Stefano

    2009-06-15

    By heating a sample of Tb/Na tobermorite we obtained a phase which was identified through its X-ray diffraction (XRD) pattern, as terbium silicate apatite. Subsequently this compound has been directly prepared by solid state reaction and we carried out a structural refinement from XRD data in space group P6{sub 3}/m obtaining cell parameters a=9.39199(4) A and c=6.84041(5) A. Terbium silicate apatite heated in melted NaF led to Tb{sub 4}O{sub 7} crystals. - Graphical Abstract: By heating over 900 deg. C Tb/Na tobermorite a terbium silicate apatite was obtained. The same product has been independently prepared and structurally characterized from powder diffraction data. Attempts of crystallizing terbium silicate apatite from melted NaF led to Tb{sub 4}O{sub 7} crystals.

  8. The liquid krypton calorimeter of NA48: First operation results

    NASA Astrophysics Data System (ADS)

    Costantini, F.

    1998-02-01

    The first technical run of the complete NA48 experimental apparatus took place in 1996. The first operation results of the full size liquid Krypton electromagnetic calorimeter as energy resolution and π 0 mass resolution are presented in this paper.

  9. Regulation of Na v channels in sensory neurons.

    PubMed

    Chahine, Mohamed; Ziane, Rahima; Vijayaragavan, Kausalia; Okamura, Yasushi

    2005-10-01

    Voltage-gated Na(+) channels have an essential role in the biophysical properties of nociceptive neurons. Factors that regulate Na(+) channel function are of interest from both pathophysiological and therapeutic perspectives. Increasing evidence indicates that changes in expression or inappropriate modulation of these channels leads to electrical instability of the cell membrane and the inappropriate spontaneous activity that is observed following nerve injury, and that this might contribute to neuropathic pain. The role of Na(v) channels in nociception depends on modulation by factors such as auxiliary beta-subunits, cytoskeletal proteins and the phosphorylation state of neurons. In this review we describe the modulation of Na(v) channels on sensory neurons by auxiliary beta-subunits, protein kinases and cytoskeletal proteins.

  10. Na+ and Rb+ tracer diffusion in alkali halides

    NASA Astrophysics Data System (ADS)

    Beniere, F.; Sen, S. K.

    1991-11-01

    We have undertaken a fundamental study of heterodiffusion of foreign ions in pure single crystals. The present work describes the measurements of the diffusion coefficient of monovalent cations in some alkali halides, namely Na+ and Rb+ into KCl, KBr, NaI and KI. The priority is given to the super-accuracy of the experimental data. The target is to test the validity of the existing theories for calculating the enthalpy and entropy of migration.

  11. Na+ transport by rabbit urinary bladder, a tight epithelium.

    PubMed

    Lewis, S A; Diamond, J M

    1976-08-27

    By in vitro experiments on rabbit bladder, we reassessed the traditional view that mammalian urinary bladder lacks ion transport mechanisms. Since the ratio of actual-to-nominal membrane area in folded epithelia is variable and hard to estimate, we normalized membrane properties to apical membrane capacitance rather than to nominal area (probably 1 muF approximately 1 cm2 actual area). A new mounting technique that virtually eliminates edge damage yielded resistances up to 78,000 omega muF for rabbit bladder, and resistances for amphibian skin and bladder much higher than those usually reported. This technique made it possible to observe a transport-related conductance pathway, and a close correlation between transepithelial conductance (G) and short-circuit current (Isc) in these tight epithelia. G and Isc were increased by mucosal (Na+) [Isc approximately 0 when (Na+) approximately 0], aldosterone, serosal (HCO-3) and high mucosal (H+); were decreased by amiloride, mucosal (Ca++), ouabain, metabolic inhibitors and serosal (H+); and were unaffected by (Cl-) and little affected by antidiuretic hormone (ADH). Physiological variation in the rabbits' dietary Na+ intake caused variations in bladder G and Isc similar to those caused by the expected in vivo changes in aldosterone levels. The relation between G and Isc was the same whether defined by diet changes, natural variation among individual rabbits, or most of the above agents. A method was developed for separately resolving conductances of junctions, basolateral cell membrane, and apical cell membrane from this G--Isc relation. Net Na+ flux equalled Isc. Net Cl- flux was zero on short circuit and equalled only 25% of net Na+ flux in open circuit. Bladder membrane fragments contained a Na+-K+-activated, ouabain-inhibited ATPase. The physiological significance of Na+ absorption against steep gradients in rabbit bladder may be to maintain kidney-generated ion gradients during bladder storage of urine, especially

  12. An empirical NaKCa geothermometer for natural waters

    USGS Publications Warehouse

    Fournier, R.O.; Truesdell, A.H.

    1973-01-01

    An empirical method of estimating the last temperature of water-rock interaction has been devised. It is based upon molar Na, K and Ca concentrations in natural waters from temperature environments ranging from 4 to 340??C. The data for most geothermal waters cluster near a straight line when plotted as the function log ( Na K) + ?? log [ ??? (Ca) Na] vs reciprocal of absolute temperature, where ?? is either 1 3 or 4 3 depending upon whether the water equilibrated above or below 100??C. For most waters tested, the method gives better results than the Na K methods suggested by other workers. The ratio Na K should not be used to estimate temperature if ??? ( MCa) MNa is greater than 1. The Na K values of such waters generally yield calculated temperatures much higher than the actual temperature at which water interacted with the rock. A comparison of the composition of boiling hot-spring water with that obtained from a nearby well (170??C) in Yellowstone Park shows that continued water-rock reactions may occur during ascent of water even though that ascent is so rapid that little or no heat is lost to the country rock, i.e. the water cools adiabatically. As a result of such continued reaction, waters which dissolve additional Ca as they ascend from the aquifer to the surface will yield estimated aquifer temperatures that are too low. On the other hand, waters initially having enough Ca to deposit calcium carbonate during ascent may yield estimated aquifer temperatures that are too high if aqueous Na and K are prevented from further reaction with country rock owing to armoring by calcite or silica minerals. The Na-K-Ca geothermometer is of particular interest to those prospecting for geothermal energy. The method also may be of use in interpreting compositions of fluid inclusions. ?? 1973.

  13. Na sup + -glycine cotransport in canalicular liver plasma membrane vesicles

    SciTech Connect

    Moseley, R.H.; Ballatori, N.; Murphy, S.M. Yale Univ. School of Medicine, New Haven, CT Univ. of Rochester School of Medicine and Dentistry, NY )

    1988-08-01

    By use of purified rat canalicular liver plasma membrane (cLPM) vesicles, the present study determined the driving forces for glycine transport across this membrane domain. Initial rates of ({sup 3}H)glycine uptake in cLPM vesicles were stimulated by an inwardly directed Na{sup +} gradient but not by a K{sup +} gradient. Na{sup +} gradient-dependent uptake of glycine demonstrated cation specificity for Na{sup +}, dependence on extravesicular Cl{sup {minus}}, stimulation by an intravesicular-negative membrane potential, and inhibition by dissipation of the Na{sup +} gradient with gramicidin D. Na{sup +} gradient-dependent glycine cotransport also demonstrated greater sensitivity to inhibition by sarcosine than 2-(methylamino)-isobutyric acid. Accelerated exchange diffusion of ({sup 3}H)glycine was demonstrated in the presence of Na{sup +} when cLPM vesicles were preloaded with glycine but not with L-alanine or L-proline. Substrate velocity analysis of net Na{sup +}-dependent ({sup 3}H)glycine uptake over the range of amino acid concentrations from 5 {mu}M to 5 mM demonstrated two saturable transport systems, one of high capacity and low affinity and one of low capacity and comparatively high affinity. These results indicate that, in addition to previously described neutral and anionic amino acid transport systems, Na{sup +} gradient-dependent glycine transport mechanisms are present on the canalicular domain of the liver plasma membrane. These canalicular reabsorptive mechanisms may serve to reclaim some of the glycine generated within the canalicular lumen from the intrabiliary hydrolysis of glutathione.

  14. High performance MCFC using Li/Na electrolyte

    SciTech Connect

    Donado, R.A.; Ong, E.T.; Sishtla, C.I.

    1995-08-01

    The substitution of a lithium/ sodium carbonate (Li/Na) mixture for the lithium/potassium carbonate (Li/K) electrolyte used in MCFCs holds the promise of higher ionic conductivity, higher exchange current density at both electrodes, lower vapor pressure, and lower cathode dissolution rates. However, when the substitution is made in cells optimized for use with the Li/K electrolyte, the promised increase in performance is not realized. As a consequence the literature contains conflicting data with regard to the performance, compositional stability, and chemical reactivity of the Li/Na electrolyte. Experiments conducted at the Institute of Gas Technology (IGT) concluded that the source of the problem is the different wetting characteristics of the two electrolytes. Electrode pore structures optimized for use with Li/K do not work well with Li/Na. Using proprietary methods and materials, IGT was able to optimize a set of electrodes for the Li/Na electrolyte. Experiments conducted in bench-scale cells have confirmed the superior performance of the Li/Na electrolyte compared to the Li/K electrolyte. The Li/Na cells exhibited a 5 to 8 percent improvement in overall performance, a substantial decrease in the rate of cathode dissolution, and a decreased decay rate. The longest running cell has logged over 13,000 hours of operation with a decay rate of less than 2 mV/1000 hours.

  15. Deliquescence of NaCl–NaNO3, KNO3–NaNO3, and NaCl–KNO3 salt mixtures from 90 to 120°C

    PubMed Central

    Carroll, Susan; Craig, Laura; Wolery, Thomas J

    2005-01-01

    We conducted reversed deliquescence experiments in saturated NaCl–NaNO3–H2O, KNO3–NaNO3–H2O, and NaCl–KNO3–H2O systems from 90 to 120°C as a function of relative humidity and solution composition. NaCl, NaNO3, and KNO3 represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV. Discrepancy between model prediction and experiment can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25°C models for Cl–NO3 and K–NO3 ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the nonideal behavior of these highly concentrated solutions.

  16. 23Na and 1H NMR Microimaging of Intact Plants

    NASA Astrophysics Data System (ADS)

    Olt, Silvia; Krötz, Eva; Komor, Ewald; Rokitta, Markus; Haase, Axel

    2000-06-01

    23Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using 23Na as well as 1H NMR microimaging. Experiments were performed at 11.75 T with a double resonant 23Na-1H probehead. The probehead was homebuilt and equipped with a climate chamber. T1 and T2 of 23Na were measured in the cross section of the hypocotyl. Within 85 min 23Na images with an in-plane resolution of 156 × 156 μm were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, 23Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

  17. thin films grown with additional NaF layers

    NASA Astrophysics Data System (ADS)

    Kim, Gee Yeong; Kim, Juran; Jo, William; Son, Dae-Ho; Kim, Dae-Hwan; Kang, Jin-Kyu

    2014-10-01

    CZTS precursors [SLG/Mo (300 nm)/ZnS (460 nm)/SnS (480 nm)/Cu (240 nm)] were deposited by RF/DC sputtering, and then NaF layers (0, 15, and 30 nm) were grown by electron beam evaporation. The precursors were annealed in a furnace with Se metals at 590°C for 20 minutes. The final composition of the CZTSSe thin-films was of Cu/(Zn + Sn) ~ 0.88 and Zn/Sn ~ 1.05, with a metal S/Se ratio estimated at ~0.05. The CZTSSe thin-films have different NaF layer thicknesses in the range from 0 to 30 nm, achieving a ~3% conversion efficiency, and the CZTSSe thin-films contain ~3% of Na. Kelvin probe force microscopy was used to identify the local potential difference that varied according to the thickness of the NaF layer on the CZTSSe thin-films. The potential values at the grain boundaries were observed to increase as the NaF thickness increased. Moreover, the ratio of the positively charged GBs in the CZTSSe thin-films with an NaF layer was higher than that of pure CZTSSe thin-films. A positively charged potential was observed around the grain boundaries of the CZTSSe thin-films, which is a beneficial characteristic that can improve the performance of a device.

  18. Endogenous ouabain in renal Na(+) handling and related diseases.

    PubMed

    Manunta, Paolo; Messaggio, Elisabetta; Casamassima, Nunzia; Gatti, Guido; Carpini, Simona Delli; Zagato, Laura; Hamlyn, John M

    2010-12-01

    The Na(+) pump and its Endogenous modulator Ouabain (EO) can be considered as an ancestral enzymatic system, conserved among species ranging from Drosophila to humans, related to Na handling. In this review, we examine how EO is linked with vascular function in hypertension and if it impacts the pathogenesis of heart and renal failure. Moreover, the molecular mechanism of endogenous ouabain-linked hypertension involves the sodium pump/sodium-calcium exchanger duet. Biosynthesis of EO occurs in adrenal glands and is under the control of angiotensin II, ACTH and epinephrine. Elevated concentrations of EO and in the sub-nanomolar concentration range were found to stimulate proliferation and differentiation of cardiac and smooth muscle cells. They may have a primary role in the development of cardiac dysfunction and failure. Experimental data suggest that the Na/K-ATPase α(2)-catalytic subunit causes EO-induced vasoconstriction. Finally, maneuvers that promote Na depletion, as diuretic therapy or reduced Na intake, raise the EO levels. Taken together, these findings suggest a key role for EO in body Na homeostasis.

  19. Diffusive transport through compacted Na- and Ca-bentonite

    NASA Astrophysics Data System (ADS)

    Choi, J.-W.; Oscarson, D. W.

    1996-04-01

    The effect of exchangeable cation — Na + and Ca 2+ — on the diffusive transport of I -, Sr 2+ and 3H (as HTO) in compacted bentonite was examined using a through-diffusion method. Total intrinsic diffusion coefficients, Di, were determined from the steady-state flux of the diffusants through the clays, and apparent diffusion coefficients, Da, were obtained from the time lag technique. The clays were compacted to a dry bulk density of 1.3 Mg/m 3, and Na-bentonite was saturated with a solution of 100 mol NaCl/m3 and Ca-bentonite with one of 50 mol CaCl 2/m 3. The Di values for all diffusants are 2 to 6 times higher in the Ca- than Na-clay. We attribute this to the larger quasicrystal, or particle, size of Ca- compared to Na-bentonite. Hence, Ca-bentonite has a greater proportion of relatively large pores; this was confirmed by Hg intrusion porosimetry. This means the diffusion pathways in Ca-bentonite are less tortuous than those in Na-bentonite. Moreover, in some cases the effective porosity, or the porosity available for diffusive transport, may be greater in Ca-bentonite. The D a values are inversely proportional to the distribution coefficients of the diffusants with the clays.

  20. Cardiac Na currents and the inactivating, reopening, and waiting properties of single cardiac Na channels

    PubMed Central

    1985-01-01

    Tetrodotoxin (TTX)-sensitive Na currents were examined in single dissociated ventricular myocytes from neonatal rats. Single channel and whole cell currents were measured using the patch-clamp method. The channel density was calculated as 2/micron 2, which agreed with our usual finding of four channels per membrane patch. At 20 degrees C, the single channel conductance was 20 pS. The open time distributions were fit by a single-exponential function with a mean open time of approximately 1.0 ms at membrane potentials from -60 to -40 mV. Averaged single channel and whole cell currents were similar when scaled and showed both fast and slow rates of inactivation. The inactivation and activation gating shifted quickly to hyperpolarized potentials for channels in cell-attached as well as excised patches, whereas a much slower shift occurred in whole cells. Slowly inactivating currents were present in both whole cell and single channel current measurements at potentials as positive as -40 mV. In whole cell measurements, the potential range could be extended, and slow inactivation was present at potentials as positive as -10 mV. The curves relating steady state activation and inactivation to membrane potential had very little overlap, and slow inactivation occurred at potentials that were positive to the overlap. Slow inactivation is in this way distinguishable from the overlap or window current, and the slowly inactivating current may contribute to the plateau of the rat cardiac action potential. On rare occasions, a second set of Na channels having a smaller unit conductance and briefer duration was observed. However, a separate set of threshold channels, as described by Gilly and Armstrong (1984. Nature [Lond.]. 309:448), was not found. For the commonly observed Na channels, the number of openings in some samples far exceeded the number of channels per patch and the latencies to first opening or waiting times were not sufficiently dispersed to account for the slowly

  1. Regulation of the paracellular Na+ and Cl- conductances by the NaCl-generated osmotic gradient in a manner dependent on the direction of osmotic gradients.

    PubMed

    Tokuda, Shinsaku; Niisato, Naomi; Nakajima, Ken-Ichi; Marunaka, Yoshinori

    2008-02-01

    In the present study, we investigated the effect of osmolality on the paracellular ion conductance (Gp) composed of the Na(+) conductance (G(Na)) and the Cl(-) conductance (G(Cl)). An osmotic gradient generated by NaCl with relatively apical hypertonicity (NaCl-absorption-direction) induced a large increase in the G(Na) associated with a small increase in the G(Cl), whereas an osmotic gradient generated by NaCl with relatively basolateral hypertonicity (NaCl-secretion-direction) induced small increases in the G(Na) and the G(Cl). These increases in the Gp caused by NaCl-generated osmotic gradients were diminished by the application of sucrose canceling the NaCl-generated osmotic gradient. The osmotic gradient generated by apical [corrected] application of sucrose without any NaCl gradients had little effects on the Gp. However, this apical [corrected] application of sucrose produced a precondition drastically quickening the time course of the action of the NaCl-generated osmotic gradient on the Gp. Further, we found that application of the basolateral hypotonicity generated by reduction of NaCl concentration shifted the localization of claudin-1 to the apical from the lateral [corrected] side. These results indicate that the osmotic gradient regulates the paracellular ion conductive pathway of tight junctions via a mechanism dependent on the direction of NaCl gradients associated with a shift of claudin-1 localization to the apical side in renal A6 epithelial cells. PMID:18068115

  2. Na ordering and Co magnetism in a metallic antiferromagnet Na0.825CoO2

    NASA Astrophysics Data System (ADS)

    Young, Ben-Li; Chu, P.-Y.; Juang, J. Y.; Shu, G. J.; Chou, F. C.

    2014-03-01

    Sodium cobaltate, NaxCoO2, originally known as a battery material, has shown other prominent features such as thermoelectricity, magnetism, and superconductivity. For certain Na contents, the Na vacancies are not randomly distributed so that a superlattice structure is formed. We investigated the Na ordering and the Co magnetism in the x = 0.825 phase of a metallic antiferromagnet, by nuclear magnetic-resonance (NMR) techniques. We successfully derived the three-dimensional superstructure of the Na ordering, and found additional magnetic susceptibility component emerging at 60 K. In addition, a magnetic field-induced glassy behavior near a metamagnetic transition was discovered. This work was supported by NSC Grants No. 98-2112-M-009-016-MY3 and No. 101-2112-M-009-015-MY2 and by the MOE ATU Program operated at NCTU.

  3. Simultaneous optical excitation of Na electronic and CF{sub 4} vibrational modes in Na+CF{sub 4} collisions

    SciTech Connect

    Alekseev, V. A.; Grosser, J.; Hoffmann, O.; Rebentrost, F.

    2008-11-28

    We report on the ultraviolet excitation of Na(3s)+CF{sub 4} collision pairs in a crossed molecular beam experiment. We observe Na(3d) collision products originating from the process Na(3s)+CF{sub 4}({nu}{sub 3}=0)+h{nu}{yields}Na(3d)+CF{sub 4}({nu}{sub 3}=1). The spectral intensity distribution of the collision products and the prevailing small angle scattering confirm a previously proposed long range dipole-dipole mechanism. We report velocity-resolved spectra and a comparison to preliminary numerical results based on collisional broadening theory. Polarization experiments suggest future potential for the observation of collision geometries.

  4. NaNaX 4--4th event of the international conference series "Nanoscience with Nanocrystals".

    PubMed

    Reiss, Peter

    2010-07-27

    The conference "NaNaX 4--Nanoscience with Nanocrystals" held near Munich (April 11-15, 2010) brought together a wide range of scientists discussing the most important current issues in the field of colloidal nanoparticles. Chemical synthesis gives access to nanocrystals of controlled size, shape, composition, and surface functionalization. Past research mainly concentrated on cadmium and lead chalcogenide nanocrystals as well as on gold and iron oxide nanoparticles. Today, there is a trend toward the development of nanoscale heterostructures, which combine different classes of materials and exhibit unique optical, magnetic, and electronic properties. Beside their interest for fundamental science, colloidal nanoparticles hold great promise for a wide range of applications. To this end, speakers and poster presenters showed routes for designing and using nanocrystals in biological imaging and sensing, in energy-related applications, and in catalysis. This report gives a nonexhaustive overview of selected "hot topics" in nanoparticle research discussed at NaNaX 4.

  5. Crystallization kinetics from mixture Na2SO4/glycerol droplets of Na2SO4 by FTIR-ATR

    NASA Astrophysics Data System (ADS)

    Tan, Dan-Ting; Cai, Chen; Zhang, Yun; Wang, Na; Pang, Shu-Feng; Zhang, Yun-Hong

    2016-08-01

    The efflorescence of mixed Na2SO4/glycerol aerosols on the ZnSe substrate with various mole ratios (Na2SO4/glycerol = 1:1, 1:2, 1:4) has been studied in the relative humidity (RH) linearly decline process, using a situ Fourier transform infrared attenuated total reflection (FTIR-ATR) technique. The crystal ratio at a given RH can be gained by the absorbance of the band at 1132 cm-1, which shows the incomplete nucleation for mixed Na2SO4/glycerol aerosols and the decreased amount of the droplets crystallized at the lowest RH with the glycerol increase. Using the volume fraction of droplets that have yet to crystallize, the heterogeneous nucleation kinetics has been gained. By the Extended Aerosol Inorganics Model (E-AIM), the nucleation rate as the function of solute saturation degree has been gained for various mixed Na2SO4/glycerol aerosols.

  6. The tetrodotoxin-resistant Na+ channel Na (v)1.8 reduces the potency of local anesthetics in blocking C-fiber nociceptors.

    PubMed

    Kistner, Katrin; Zimmermann, Katharina; Ehnert, Corina; Reeh, Peter W; Leffler, Andreas

    2010-04-01

    The generation of action potentials in nociceptive neurons is accomplished by the tetrodotoxin-resistant (TTXr) Na+ channel Na(v)1.8. Following nerve injury, a redistribution of Na(v)1.8 from dorsal root ganglion (DRG) neurons into peripheral axons contributes to hyperexcitability and possibly to neuropathic pain. Na(v)1.8 has been reported to display a lower sensitivity to block by Na+ channel blockers as compared to TTX-sensitive (TTXs) Na(v) subunits. Furthermore, the antinociceptive efficacy of lidocaine is increased in Na(v)1.8-knockout mice. Here, we asked if Na(v)1.8 expression can reduce the susceptibility of sensory neurons to block by lidocaine. Employing wild-type and Na(v)1.8-knockout mice, we examined C-fibers in the skin-nerve preparation and Na+ currents in DRG neurons by patch-clamp recordings. Deletion of Na(v)1.8 resulted in an enhanced tonic block of Na+ currents in DRG neurons held at -80 mV but not at -140 mV. Accordingly, lower concentrations of lidocaine were required for a conduction block of C-fibers from Na(v)1.8-knockout as compared to wild-type mice. The efficacy of lidocaine on neurons lacking Na(v)1.8 was further increased by cold temperatures, due to a synergistic hyperpolarizing shift of the slow inactivation of TTXs Na+ channels by lidocaine and cooling. Finally, the approximately 90% reduction of TTXr Na+ currents in injured neurons from mice with a peripheral nerve injury was accompanied with an enhanced tonic block by lidocaine. In conclusion, our data demonstrate that the expression of Na(v)1.8 in sensory neurons can confine the antinociceptive efficacy of lidocaine and other Na+ channel blockers employed for pain treatment. PMID:20174994

  7. Probabilistic Models to Predict Listeria monocytogenes Growth at Low Concentrations of NaNO2 and NaCl in Frankfurters

    PubMed Central

    Gwak, Eunji; Oh, Mi-Hwa; Park, Beom-Young; Lee, Heeyoung; Lee, Soomin; Ha, Jimyeong; Lee, Jeeyeon; Kim, Sejeong; Choi, Kyoung-Hee; Yoon, Yohan

    2015-01-01

    This study developed probabilistic models to describe Listeria monocytogenes growth responses in meat products with low concentrations of NaNO2 and NaCl. A five-strain mixture of L. monocytogenes was inoculated in NBYE (nutrient broth plus 0.6% yeast extract) supplemented with NaNO2 (0-141 ppm) and NaCl (0-1.75%). The inoculated samples were then stored under aerobic and anaerobic conditions at 4, 7, 10, 12, and 15℃ for up to 60 d. Growth response data [growth (1) or no growth (0)] for each combination were determined by turbidity. The growth response data were analyzed using logistic regression to predict the growth probability of L. monocytogenes as a function of NaNO2 and NaCl. The model performance was validated with the observed growth responses. The effect of an obvious NaNO2 and NaCl combination was not observed under aerobic storage condition, but the antimicrobial effect of NaNO2 on the inhibition of L. monocytogenes growth generally increased as NaCl concentration increased under anaerobic condition, especially at 7-10℃. A single application of NaNO2 or NaCl significantly (p<0.05) inhibited L. monocytogenes growth at 4-15℃, but the combination of NaNO2 or NaCl more effectively (p<0.05) inhibited L. monocytogenes growth than single application of either compound under anaerobic condition. Validation results showed 92% agreement between predicted and observed growth response data. These results indicate that the developed model is useful in predicting L. monocytogenes growth response at low concentrations of NaNO2 and NaCl, and the antilisterial effect of NaNO2 increased by NaCl under anaerobic condition. PMID:26877642

  8. Na(+)-translocating cytochrome bo terminal oxidase from Vitreoscilla: some parameters of its Na+ pumping and orientation in synthetic vesicles.

    PubMed

    Park, C; Moon, J Y; Cokic, P; Webster, D A

    1996-09-10

    Vitreoscilla cytochrome bo ubiquinol oxidase is similar in some properties to the Escherichia coli enzyme, but unlike the latter, the Vitreoscilla oxidase functions as a primary Na+ pump. When purified Vitreoscilla cytochrome bo is incorporated into liposomes made from Vitreoscilla phospholipids and energized with a quinol substrate, it translocates Na+, not H+, across the vesicle membrane. Since protonophores CCCP (carbonyl cyanide m-chlorophenylhydrazone) and DTHB (3,5-di-tert-butyl-4-hydroxybenzaldehyde) stimulated the Na+ pumping, it is unlikely that it is a secondary effect due to the presence of Na+/H+ antiporter activity in the preparations. The efficiency of the Na+ pumping was 3.93 Na+ pumped per O2 consumed when ascorbate/TMPD was used as the substrate. The cytochrome has a K(m) and Kcat for Na+ of 2.9 mM and 277 s-1, respectively. When ferricytochrome c was entrapped within liposomes prepared from Vitreoscilla phospholipids, it was reduced by Q1H2 (ubiquinol-1) but not by ascorbate/TMPD (N,N,N',N'-tetramethyl-1,4-phenylenediamine). Although Q1H2 was oxidized by cytochrome bo in solution at a rate approximately 14 times that of the latter substrate, the rate of accumulation of Na+ within cytochrome bo vesicles driven by the membrane impermeable ascorbate/TMPD was 1.23 times that of the membrane permeable ubiquinol. These data allowed a calculation that in these synthetic proteoliposomes the cytochrome bo molecules are only 51% directed inward; a value of 61% inward-directed was estimated by measuring the ascorbate/TMPD oxidase activity of the proteoliposomes before and after disrupting them with Triton X-100. A random orientation of the E. coli cytochrome bo oxidase in proteoliposomes has also been reported. PMID:8794772

  9. Targeting Voltage Gated Sodium Channels NaV1.7, NaV1.8, and NaV1.9 for Treatment of Pathological Cough

    PubMed Central

    Muroi, Yukiko

    2015-01-01

    Recent advances in our understanding of voltage-gated sodium channels (NaVs) lead to the rational hypothesis that drugs capable of selective blockade of NaV subtypes may be a safe and effective strategy for the treatment of unwanted cough. Among the nine NaV subtypes (NaV1.1–NaV1.9), the afferent nerves involved in initiating cough, in common with nociceptive neurons in the somatosensory system, express mainly NaV1.7, NaV1.8, and NaV1.9. Although knowledge about the effect of selectively blocking these channels on the cough reflex is limited, their biophysical properties indicate that each may contribute to the hypertussive and allotussive state that typifies subacute and chronic nonproductive cough. PMID:24272479

  10. Experimental and first-principles study of photoluminescent and optical properties of Na-doped CuAlO2: the role of the NaAl-2Na i complex

    NASA Astrophysics Data System (ADS)

    Liu, Ruijian; Li, Yongfeng; Yao, Bin; Ding, Zhanhui; Deng, Rui; Zhang, Ligong; Zhao, Haifeng; Liu, Lei

    2015-08-01

    We report that a band-tail emission at 3.08 eV, lower than near-band-edge energy, is observed in photoluminescence measurements of bulk Na-doped CuAlO2. The band-tail emission is attributed to Na-related defects. Electronic structure calculations based on the first-principles method demonstrate that the donor-acceptor compensated complex of NaAl-2Na i in Na-doped CuAlO2 plays a key role in leading to the band-tail emission and bandgap narrowing. Furthermore, Hall effect measurements indicates that the hole concentration in CuAlO2 is independent on Na doping, which is well understood by the donor-acceptor compensation effect of NaAl-2Na i complex.

  11. Na(+) -Activated K(+) Channels in Rat Supraoptic Neurones.

    PubMed

    Bansal, V; Fisher, T E

    2016-06-01

    The magnocellular neurosecretory cells (MNCs) of the hypothalamus secrete the neurohormones vasopressin and oxytocin. The systemic release of these hormones depends on the rate and pattern of MNC firing and it is therefore important to identify the ion channels that contribute to the electrical behaviour of MNCs. In the present study, we report evidence for the presence of Na(+) -activated K(+) (KN a ) channels in rat MNCs. KN a channels mediate outwardly rectifying K(+) currents activated by the increases in intracellular Na(+) that occur during electrical activity. Although the molecular identity of native KN a channels is unclear, their biophysical properties are consistent with those of expressed Slick (slo 2.1) and Slack (slo 2.2) proteins. Using immunocytochemistry and Western blot experiments, we found that both Slick and Slack proteins are expressed in rat MNCs. Using whole cell voltage clamp techniques on acutely isolated rat MNCs, we found that inhibiting Na(+) influx by the addition of the Na(+) channel blocker tetrodotoxin or the replacement of Na(+) in the external solution with Li(+) caused a significant decrease in sustained outward currents. Furthermore, the evoked outward current density was significantly higher in rat MNCs using patch pipettes containing 60 mm Na(+) than it was when patch pipettes containing 0 mm Na(+) were used. Our data show that functional KN a channels are expressed in rat MNCs. These channels could contribute to the activity-dependent afterhyperpolarisations that have been identified in the MNCs and thereby play a role in the regulation of their electrical behaviour. PMID:27091544

  12. NMR Evidence for Complexing of Na+ in Muscle, Kidney, and Brain, and by Actomyosin. The Relation of Cellular Complexing of Na+ to Water Structure and to Transport Kinetics

    PubMed Central

    Cope, Freeman W.

    1967-01-01

    The nuclear magnetic resonance (NMR) spectrum of Na+ is suitable for qualitative and quantitative analysis of Na+ in tissues. The width of the NMR spectrum is dependent upon the environment surrounding the individual Na+ ion. NMR spectra of fresh muscle compared with spectra of the same samples after ashing show that approximately 70% of total muscle Na+ gives no detectable NMR spectrum. This is probably due to complexation of Na+ with macromolecules, which causes the NMR spectrum to be broadened beyond detection. A similar effect has been observed when Na+ interacts with ion exchange resin. NMR also indicates that about 60% of Na+ of kidney and brain is complexed. Destruction of cell structure of muscle by homogenization little alters the per cent complexing of Na+. NMR studies show that Na+ is complexed by actomyosin, which may be the molecular site of complexation of some Na+ in muscle. The same studies indicate that the solubility of Na+ in the interstitial water of actomyosin gel is markedly reduced compared with its solubility in liquid water, which suggests that the water in the gel is organized into an icelike state by the nearby actomyosin molecules. If a major fraction of intracellular Na+ exists in a complexed state, then major revisions in most theoretical treatments of equilibria, diffusion, and transport of cellular Na+ become appropriate. PMID:6033590

  13. Thyroid thermogenesis. Relationships between Na+-dependent respiration and Na+ + K+-adenosine triphosphatase activity in rat skeletal muscle.

    PubMed Central

    Asano, Y; Liberman, U A; Edelman, I S

    1976-01-01

    The effect of thyroid status on QO2, QO2 (t) and NaK-ATPase activity was examined in rat skeletal muscle. QO2(t) (i.e. Na+-transport-dependent respiration) was estimated with ouabain or Na+-free media supplemented with K+. In contrast to the effects of ouabain on ion composition, intracellular K+ was maintained at about 125 meq/liter, and intracellular Na+ was almost nil in the Na+-free media. The estimates of QO2(t) were independent of the considerable differences in tissue ion concentrations. The increase in QO2(t) account for 47% of the increase in QO2 in the transition from the hypothyroid to the euthyroid state and 84% of the increase in the transition from the euthyroid to the hyperthyroid state. Surgical thyroidectomy lowered NaK-ATPase activity of the microsomal fraction (expressed per milligram protein) 32%; injections of triodothyronine (T3) increased this activity 75% in initially hypothyroid rats and 26% in initially euthyroid rats. Thyroidectomy was attended by significant falls in serum Ca and Pi concentrations. Administration of T3 resulted in further declines in serum Ca and marked increases in serum Ps concentrations. Similar effects were seen in 131I-treated rats, but the magnitude of the declines in serum Ca were less. The effects of T3 on QO2, QO2(t), and NaK-ATPase activity of skeletal muscle were indistinguishable in the 131I-ablated and surgically thyroidectomized rats. In thyroidectomized or euthyroid rats given repeated doses of T3, QO2(t) and NaA-ATPase activity increased proportionately. In thyroidectomized rats injected with single doses of T3, either 10, 50, or 250 mug/100 g body wt, QO2(t) increased linearly with NaK-ATPase activity. The kinetics of the NaK-ATPase activity was assessed with an ATP-generating system. T3 elicited a significant increase in Vmax with no change in Km for ATP. PMID:130385

  14. 75 FR 38874 - Proposed Collection; Comment Request for Form 706-NA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-06

    ... Internal Revenue Service Proposed Collection; Comment Request for Form 706-NA AGENCY: Internal Revenue...(c)(2)(A)). Currently, the IRS is soliciting comments concerning Form 706-NA, United States Estate...-0531. Form Number: 706-NA. Abstract: Form 706-NA is used to compute estate and generation-...

  15. C-peptide, Na+,K+-ATPase, and Diabetes

    PubMed Central

    Coste, T. C.; Jannot, M. F.; Raccah, D.; Tsimaratos, M.

    2004-01-01

    Na+,K+-ATPase is an ubiquitous membrane enzyme that allows the extrusion of three sodium ions from the cell and two potassium ions from the extracellular fluid. Its activity is decreased in many tissues of streptozotocin-induced diabetic animals. This impairment could be at least partly responsible for the development of diabetic complications. Na+,K+-ATPase activity is decreased in the red blood cell membranes of type 1 diabetic individuals, irrespective of the degree of diabetic control. It is less impaired or even normal in those of type 2 diabetic patients. The authors have shown that in the red blood cells of type 2 diabetic patients, Na+,K+-ATPase activity was strongly related to blood C-peptide levels in non–insulin-treated patients (in whom C-peptide concentration reflects that of insulin) as well as in insulin-treated patients. Furthermore, a gene-environment relationship has been observed. The alpha-1 isoform of the enzyme predominant in red blood cells and nerve tissue is encoded by the ATP1A1 gene.Apolymorphism in the intron 1 of this gene is associated with lower enzyme activity in patients with C-peptide deficiency either with type 1 or type 2 diabetes, but not in normal individuals. There are several lines of evidence for a low C-peptide level being responsible for low Na+,K+-ATPase activity in the red blood cells. Short-term C-peptide infusion to type 1 diabetic patients restores normal Na+,K+-ATPase activity. Islet transplantation, which restores endogenous C-peptide secretion, enhances Na+,K+-ATPase activity proportionally to the rise in C-peptide. This C-peptide effect is not indirect. In fact, incubation of diabetic red blood cells with C-peptide at physiological concentration leads to an increase of Na+,K+-ATPase activity. In isolated proximal tubules of rats or in the medullary thick ascending limb of the kidney, C-peptide stimulates in a dose-dependent manner Na+,K+-ATPase activity. This impairment in Na+,K+-ATPase activity, mainly

  16. Adenosine, type 1 receptors: role in proximal tubule Na+ reabsorption

    PubMed Central

    Welch, William J

    2015-01-01

    Adenosine type 1 receptor (A1-AR) antagonists induce diuresis and natriuresis in experimental animals and humans. Much of this effect is due to inhibition of A1-ARs in the proximal tubule, which is responsible for 60–70% of the reabsorption of filtered Na+ and fluid. Intratubular application of receptor antagonists indicates that A1-AR mediates a portion of Na+ uptake in PT and PT cells, via multiple transport systems, including Na+/H+ exchanger-3 (NHE3), Na+/PO4− co-transporter and Na+-dependent glucose transporter, SGLT. Renal microperfusion and recollection studies have shown that fluid reabsorption is reduced by A1-AR antagonists and is lower in A1-AR KO mice., compared to WT mice. Absolute proximal reabsorption (APR) measured by free-flow micropuncture is equivocal, with studies that show either lower APR or similar APR in A1-AR KO mice, compared to WT mice. Inhibition of A1-ARs lowers elevated blood pressure in models of salt-sensitive hypertension, partially due to their effects in the proximal tubule. PMID:25345761

  17. Links between hydrothermal environments, pyrophosphate, na(+), and early evolution.

    PubMed

    Holm, Nils G; Baltscheffsky, Herrick

    2011-10-01

    The discovery that photosynthetic bacterial membrane-bound inorganic pyrophosphatase (PPase) catalyzed light-induced phosphorylation of orthophosphate (Pi) to pyrophosphate (PPi) and the capability of PPi to drive energy requiring dark reactions supported PPi as a possible early alternative to ATP. Like the proton-pumping ATPase, the corresponding membrane-bound PPase also is a H(+)-pump, and like the Na(+)-pumping ATPase, it can be a Na(+)-pump, both in archaeal and bacterial membranes. We suggest that PPi and Na(+) transport preceded ATP and H(+) transport in association with geochemistry of the Earth at the time of the origin and early evolution of life. Life may have started in connection with early plate tectonic processes coupled to alkaline hydrothermal activity. A hydrothermal environment in which Na(+) is abundant exists in sediment-starved subduction zones, like the Mariana forearc in the W Pacific Ocean. It is considered to mimic the Archean Earth. The forearc pore fluids have a pH up to 12.6, a Na(+)-concentration of 0.7 mol/kg seawater. PPi could have been formed during early subduction of oceanic lithosphere by dehydration of protonated orthophosphates. A key to PPi formation in these geological environments is a low local activity of water.

  18. Estragole blocks neuronal excitability by direct inhibition of Na+ channels

    PubMed Central

    Silva-Alves, K.S.; Ferreira-da-Silva, F.W.; Peixoto-Neves, D.; Viana-Cardoso, K.V.; Moreira-Júnior, L.; Oquendo, M.B.; Oliveira-Abreu, K.; Albuquerque, A.A.C.; Coelho-de-Souza, A.N.; Leal-Cardoso, J.H.

    2013-01-01

    Estragole is a volatile terpenoid, which occurs naturally as a constituent of the essential oils of many plants. It has several pharmacological and biological activities. The objective of the present study was to investigate the mechanism of action of estragole on neuronal excitability. Intact and dissociated dorsal root ganglion neurons of rats were used to record action potential and Na+ currents with intracellular and patch-clamp techniques, respectively. Estragole blocked the generation of action potentials in cells with or without inflexions on their descendant (repolarization) phase (Ninf and N0 neurons, respectively) in a concentration-dependent manner. The resting potentials and input resistances of Ninf and N0 cells were not altered by estragole (2, 4, and 6 mM). Estragole also inhibited total Na+ current and tetrodotoxin-resistant Na+ current in a concentration-dependent manner (IC50 of 3.2 and 3.6 mM, respectively). Kinetic analysis of Na+ current in the presence of 4 mM estragole showed a statistically significant reduction of fast and slow inactivation time constants, indicating an acceleration of the inactivation process. These data demonstrate that estragole blocks neuronal excitability by direct inhibition of Na+ channel conductance activation. This action of estragole is likely to be relevant to the understanding of the mechanisms of several pharmacological effects of this substance. PMID:24345915

  19. Magnetism in Na-filled Fe-based skutterudites.

    PubMed

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J

    2015-06-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. Here we investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form.

  20. Associated proteins and renal epithelial Na+ channel function.

    PubMed

    Ismailov, I I; Berdiev, B K; Bradford, A L; Awayda, M S; Fuller, C M; Benos, D J

    1996-01-01

    The hypothesis that amiloride-sensitive Na+ channel complexes immunopurified from bovine renal papillary collecting tubules contain, as their core conduction component, an ENaC subunit, was tested by functional and immunological criteria. Disulfide bond reduction with dithiothreitol (DTT) of renal Na+ channels incorporated into planar lipid bilayers caused a reduction of single channel conductance from 40 pS to 13 pS, and uncoupled PKA regulation of this channel. The cation permeability sequence, as assessed from bi-ionic reversal potential measurements, and apparent amiloride equilibrium dissociation constant (K(amil)i) of the Na+ channels were unaltered by DTT treatment. Like ENaC, the DTT treated renal channel became mechanosensitive, and displayed a substantial decrease in K(amil)i following stretch (0.44 +/- 0.12 microM versus 6.9 +/- 1.0 microM). Moreover, stretch activation induced a loss in the channel's ability to discriminate between monovalent cations, and even allowed Ca2+ to permeate. Polyclonal antibodies generated against a fusion protein of alpha bENaC recognized a 70 kDa polypeptide component of the renal Na+ channel complex. These data suggest that ENaC is present in the immunopurified renal Na+ channel protein complex, and that PKA sensitivity is conferred by other associated proteins. PMID:8834119

  1. Kinetic comparisons of heart and kidney Na+,K(+)-ATPases.

    PubMed

    Garcia, Alvaro; Rasmussen, Helge H; Apell, Hans-Jürgen; Clarke, Ronald J

    2012-08-22

    Most kinetic measurements of the partial reactions of Na(+),K(+)-ATPase have been conducted on enzyme from mammalian kidney. Here we present a kinetic model that is based on the available equilibrium and kinetic parameters of purified kidney enzyme, and allows predictions of its steady-state turnover and pump current in intact cells as a function of ion and ATP concentrations and the membrane voltage. Using this model, we calculated the expected dependence of the pump current on voltage and extracellular Na(+) concentration. The simulations indicate a lower voltage dependence at negative potentials of the kidney enzyme in comparison with heart muscle Na(+),K(+)-ATPase, in agreement with experimental results. The voltage dependence is enhanced at high extracellular Na(+) concentrations. This effect can be explained by a voltage-dependent depopulation of extracellular K(+) ion binding sites on the E2P state and an increase in the proportion of enzyme in the E1P(Na(+))(3) state in the steady state. This causes a decrease in the effective rate constant for occlusion of K(+) by the E2P state and hence a drop in turnover. Around a membrane potential of zero, negligible voltage dependence is observed because the voltage-independent E2(K(+))(2) → E1 + 2K(+) transition is the major rate-determining step. PMID:22947929

  2. Magnetism in Na-filled Fe-based skutterudites

    SciTech Connect

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J.

    2015-06-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. We investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form.

  3. Magnetism in Na-filled Fe-based skutterudites

    DOE PAGESBeta

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J.

    2015-06-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. We investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material nearmore » an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form.« less

  4. High-Pressure Polymorph of NaBiO3.

    PubMed

    Naa, Octavianti; Kumada, Nobuhiro; Miura, Akira; Takei, Takahiro; Azuma, Masaki; Kusano, Yoshihiro; Oka, Kengo

    2016-06-20

    A new high-pressure polymorph of NaBiO3 (hereafter β-NaBiO3) was synthesized under the conditions of 6 GPa and 600 °C. The powder X-ray diffraction pattern of this new phase was indexed with a hexagonal cell of a = 9.968(1) Å and c = 3.2933(4) Å. Crystal structure refinement using synchrotron powder X-ray diffraction data led to RWP = 8.53% and RP = 5.55%, and the crystal structure was closely related with that of Ba2SrY6O12. No photocatalytic activity for phenol decomposition was observed under visible-light irradiation in spite of a good performance for its mother compound, NaBiO3. The optical band-gap energy of β-NaBiO3 was narrower than that of NaBiO3, which was confirmed with density of states curves simulated by first-principles density functional theory calculation. PMID:27243818

  5. Links Between Hydrothermal Environments, Pyrophosphate, Na+, and Early Evolution

    NASA Astrophysics Data System (ADS)

    Holm, Nils G.; Baltscheffsky, Herrick

    2011-10-01

    The discovery that photosynthetic bacterial membrane-bound inorganic pyrophosphatase (PPase) catalyzed light-induced phosphorylation of orthophosphate (Pi) to pyrophosphate (PPi) and the capability of PPi to drive energy requiring dark reactions supported PPi as a possible early alternative to ATP. Like the proton-pumping ATPase, the corresponding membrane-bound PPase also is a H+-pump, and like the Na+-pumping ATPase, it can be a Na+-pump, both in archaeal and bacterial membranes. We suggest that PPi and Na+ transport preceded ATP and H+ transport in association with geochemistry of the Earth at the time of the origin and early evolution of life. Life may have started in connection with early plate tectonic processes coupled to alkaline hydrothermal activity. A hydrothermal environment in which Na+ is abundant exists in sediment-starved subduction zones, like the Mariana forearc in the W Pacific Ocean. It is considered to mimic the Archean Earth. The forearc pore fluids have a pH up to 12.6, a Na+-concentration of 0.7 mol/kg seawater. PPi could have been formed during early subduction of oceanic lithosphere by dehydration of protonated orthophosphates. A key to PPi formation in these geological environments is a low local activity of water.

  6. Magnetism in Na-filled Fe-based skutterudites

    PubMed Central

    Xing, Guangzong; Fan, Xiaofeng; Zheng, Weitao; Ma, Yanming; Shi, Hongliang; Singh, David J.

    2015-01-01

    The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. Here we investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form. PMID:26027504

  7. Na(7)Mg(13)Nd(PO(4))(12).

    PubMed

    Jerbi, Hasna; Hidouri, Mourad; Mongi, Ben Amara

    2012-06-01

    Investigations of the quasi-ternary system Na(3)PO(4)-Mg(3)(PO(4))(2)-NdPO(4) allowed us to obtain the new phosphate hepta-sodium trideca-magnesium neodymium dodeca-kis-phosphate, Na(7)Mg(13)Nd(PO(4))(12), by applying a flux method. The crystal structure is isotypic with that of the previously reported Na(7)Mg(13)Ln(PO(4))(12) (Ln = Eu, La) compounds. It consists of a complex three-dimensional framework built up from an NdO(8) polyhedron (m symmetry), an MO(6) octa-hedron statistically occupied by M = Mg and Na, and eight MgO(x) (x = 5, 6) polyhedra (four with site symmetry m), linked either directely by sharing corners, edges and faces, or by one of the eight unique PO(4) tetra-hedra through common corners. Two of the PO(4) tetra-hedra are statisticaly disordered over a mirror plane. The whole structure can be described as resutling from an assembly of two types of structural units, viz [Mg(4)MP(4)O(22)](∞) (2) layers extending parallel to (100) and stacked along [100], and [Mg(4)NdP(4)O(36)](∞) (1) undulating chains running along the [010] direction. The six different Na(+) cations (five with site symmetry m and one with 0.5 occupancy) are situated in six distinct cavities delimited by the framework. The structure was refined from data of a racemic twin.

  8. Gramicidin A directly inhibits mammalian Na(+)/K (+)-ATPase.

    PubMed

    Takada, Yohei; Matsuo, Kentaro; Kataoka, Takao

    2008-12-01

    The linear pentadecapeptide gramicidin A forms an ion channel in the lipid bilayer to selectively transport monovalent cations. Nevertheless, we have surprisingly found that gramicidin A directly inhibits mammalian Na(+)/K(+)-ATPase. Gramicidin A inhibited ATP hydrolysis by Na(+)/K(+)-ATPase from porcine cerebral cortex at the IC(50) value of 8.1 microM, while gramicidin S was approximately fivefold less active. The synthetic gramicidin A analog lacking N-terminal formylation and C-terminal ethanolamine exhibited a weaker inhibitory effect on the ATP-hydrolyzing activity of Na(+)/K(+)-ATPase than gramicidin A, indicating that these end modifications are necessary for gramicidin A to inhibit Na(+)/K(+)-ATPase activity. Moreover, Lineweaver-Burk analysis showed that gramicidin A exhibits a mixed type of inhibition. In addition to the most well-studied ionophore activity, our present study has disclosed a novel biological function of gramicidin A as a direct inhibitor of mammalian Na(+)/K(+)-ATPase activity.

  9. The Na(+) transporter, TaHKT1;5-D, limits shoot Na(+) accumulation in bread wheat.

    PubMed

    Byrt, Caitlin Siobhan; Xu, Bo; Krishnan, Mahima; Lightfoot, Damien James; Athman, Asmini; Jacobs, Andrew Keith; Watson-Haigh, Nathan S; Plett, Darren; Munns, Rana; Tester, Mark; Gilliham, Matthew

    2014-11-01

    Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na(+) -selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na(+) concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na(+) from the xylem vessels in the root and has an important role in restricting the transport of Na(+) from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na(+) exclusion and is critical in maintaining a high K(+) /Na(+) ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes. PMID:25158883

  10. The Na(+) transporter, TaHKT1;5-D, limits shoot Na(+) accumulation in bread wheat.

    PubMed

    Byrt, Caitlin Siobhan; Xu, Bo; Krishnan, Mahima; Lightfoot, Damien James; Athman, Asmini; Jacobs, Andrew Keith; Watson-Haigh, Nathan S; Plett, Darren; Munns, Rana; Tester, Mark; Gilliham, Matthew

    2014-11-01

    Bread wheat (Triticum aestivum L.) has a major salt tolerance locus, Kna1, responsible for the maintenance of a high cytosolic K(+) /Na(+) ratio in the leaves of salt stressed plants. The Kna1 locus encompasses a large DNA fragment, the distal 14% of chromosome 4DL. Limited recombination has been observed at this locus making it difficult to map genetically and identify the causal gene. Here, we decipher the function of TaHKT1;5-D, a candidate gene underlying the Kna1 locus. Transport studies using the heterologous expression systems Saccharomyces cerevisiae and Xenopus laevis oocytes indicated that TaHKT1;5-D is a Na(+) -selective transporter. Transient expression in Arabidopsis thaliana mesophyll protoplasts and in situ polymerase chain reaction indicated that TaHKT1;5-D is localised on the plasma membrane in the wheat root stele. RNA interference-induced silencing decreased the expression of TaHKT1;5-D in transgenic bread wheat lines which led to an increase in the Na(+) concentration in the leaves. This indicates that TaHKT1;5-D retrieves Na(+) from the xylem vessels in the root and has an important role in restricting the transport of Na(+) from the root to the leaves in bread wheat. Thus, TaHKT1;5-D confers the essential salinity tolerance mechanism in bread wheat associated with the Kna1 locus via shoot Na(+) exclusion and is critical in maintaining a high K(+) /Na(+) ratio in the leaves. These findings show there is potential to increase the salinity tolerance of bread wheat by manipulation of HKT1;5 genes.

  11. EDITORIAL: TaCoNa-Photonics 2008 TaCoNa-Photonics 2008

    NASA Astrophysics Data System (ADS)

    Chigrin, Dmitry N.; Busch, Kurt; Lavrinenko, Andrei V.

    2009-11-01

    This special section on theoretical and computational nano-photonics features papers presented at the first International Workshop on Theoretical and Computational Nano-Photonics (TaCoNa-Photonics 2008) held in Bad Honnef, Germany, 3-5 December 2008. The workshop covered a broad range of topics related to current developments and achievements in this interdisciplinary area of research. Since the late 1960s, the word `photonics' has been understood as the science of generating, controlling, and detecting light. Nowadays, a routine fabrication of complex structures with micro- and nano-scale dimensions opens up many new and exciting possibilities in photonics. The science of generating, routing and detecting light in micro- and nano-structured matter, `nano-photonics', is becoming more important both in research and technology and offers many promising applications. The inherently sub-wavelength character of the structures that nano-photonics deals with challenges modern theoretical and computational physics and engineering with many nontrivial questions: Up to what length-scale can one use a macroscopic phenomenological description of matter? Where is the interface between the classical and quantum description of light in nano-scale structures? How can one combine different physical systems, different time- and length-scales in a single computational model? How can one engineer nano-structured materials in order to achieve the desired optical properties for particular applications? Any attempt at answering these kinds of questions is impossible without the joint efforts of physicists, engineers, applied mathematicians and programmers. This is the reason why the major goal of the TaCoNa-Photonics workshops is to provide a forum where theoreticians and specialists in numerical methods from all branches of physics, engineering sciences and mathematics can compare their results, report on novel results and breakthroughs, and discuss new challenges ahead. In order to

  12. Results of tests of weathered K5NA closeout material in the MSFC Hot Gas Facility

    NASA Technical Reports Server (NTRS)

    Dean, W. G.

    1982-01-01

    The application of K5NA over hypolon was investigated. The effects of using K5NA over painted cork surfaces, the effects of weathering on the unpainted K5NA surfaces are determined, and the use of water versus solvent for tooling K5NA in place were compared. It is concluded that: (1) K5NA can be applied to hypalon surfaces; (2) K5NA can be left unpainted; and (3) K5NA can be tested with water or solvent.

  13. High-NA HPCS optical fibers for medical diagnosis and treatment

    NASA Astrophysics Data System (ADS)

    Skutnik, Bolesh J.

    2010-02-01

    Hard Plastic Clad Silica (HPCS) optical fibers with pure silica cores have been developed which are robust and have NA(Numerical Aperture)>0.50. Improved clad only HPCS fibers have been produced for both new 'standard' and 'high' NA versions. Based on new cladding formulations, the 'standard' NA fiber has an NA of 0.41, while the new ultrahigh NA fiber has an NA of 0.54. Mechanical strength and preliminary fatigue data are presented along with spectral characterization data. For the first time significant results were obtained for clad only high NA fibers, The fibers are useful for diagnostic and surgical applications. Short to medium length time to failure results, indicate that the static fatigue parameters of the new high numerical aperture (NA) optical fibers are at least as good as those for former standard NA (0.37) HPCS fibers, which is an advance from previous results on the older formulation high NA fibers.

  14. Chronic and selective inhibition of basolateral membrane Na-K-ATPase uniquely regulates brush border membrane Na absorption in intestinal epithelial cells

    PubMed Central

    Manoharan, Palanikumar; Gayam, Swapna; Arthur, Subha; Palaniappan, Balasubramanian; Singh, Soudamani; Dick, Gregory M.

    2015-01-01

    Na-K-ATPase, an integral membrane protein in mammalian cells, is responsible for maintaining the favorable intracellular Na gradient necessary to promote Na-coupled solute cotransport processes [e.g., Na-glucose cotransport (SGLT1)]. Inhibition of brush border membrane (BBM) SGLT1 is, at least in part, due to the diminished Na-K-ATPase in villus cells from chronically inflamed rabbit intestine. The aim of the present study was to determine the effect of Na-K-ATPase inhibition on the two major BBM Na absorptive pathways, specifically Na-glucose cotransport and Na/H exchange (NHE), in intestinal epithelial (IEC-18) cells. Na-K-ATPase was inhibited using 1 mM ouabain or siRNA for Na-K-ATPase-α1 in IEC-18 cells. SGLT1 activity was determined as 3-O-methyl-d-[3H]glucose uptake. Na-K-ATPase activity was measured as the amount of inorganic phosphate released. Treatment with ouabain resulted in SGLT1 inhibition at 1 h but stimulation at 24 h. To further characterize this unexpected stimulation of SGLT1, siRNA silencing was utilized to inhibit Na-K-ATPase-α1. SGLT1 activity was significantly upregulated by Na-K-ATPase silencing, while NHE3 activity remained unaltered. Kinetics showed that the mechanism of stimulation of SGLT1 activity was secondary to an increase in affinity of the cotransporter for glucose without a change in the number of cotransporters. Molecular studies demonstrated that the mechanism of stimulation was not secondary to altered BBM SGLT1 protein levels. Chronic and direct silencing of basolateral Na-K-ATPase uniquely regulates BBM Na absorptive pathways in intestinal epithelial cells. Specifically, while BBM NHE3 is unaffected, SGLT1 is stimulated secondary to enhanced affinity of the cotransporter. PMID:25652450

  15. Chronic and selective inhibition of basolateral membrane Na-K-ATPase uniquely regulates brush border membrane Na absorption in intestinal epithelial cells.

    PubMed

    Manoharan, Palanikumar; Gayam, Swapna; Arthur, Subha; Palaniappan, Balasubramanian; Singh, Soudamani; Dick, Gregory M; Sundaram, Uma

    2015-04-15

    Na-K-ATPase, an integral membrane protein in mammalian cells, is responsible for maintaining the favorable intracellular Na gradient necessary to promote Na-coupled solute cotransport processes [e.g., Na-glucose cotransport (SGLT1)]. Inhibition of brush border membrane (BBM) SGLT1 is, at least in part, due to the diminished Na-K-ATPase in villus cells from chronically inflamed rabbit intestine. The aim of the present study was to determine the effect of Na-K-ATPase inhibition on the two major BBM Na absorptive pathways, specifically Na-glucose cotransport and Na/H exchange (NHE), in intestinal epithelial (IEC-18) cells. Na-K-ATPase was inhibited using 1 mM ouabain or siRNA for Na-K-ATPase-α1 in IEC-18 cells. SGLT1 activity was determined as 3-O-methyl-D-[(3)H]glucose uptake. Na-K-ATPase activity was measured as the amount of inorganic phosphate released. Treatment with ouabain resulted in SGLT1 inhibition at 1 h but stimulation at 24 h. To further characterize this unexpected stimulation of SGLT1, siRNA silencing was utilized to inhibit Na-K-ATPase-α1. SGLT1 activity was significantly upregulated by Na-K-ATPase silencing, while NHE3 activity remained unaltered. Kinetics showed that the mechanism of stimulation of SGLT1 activity was secondary to an increase in affinity of the cotransporter for glucose without a change in the number of cotransporters. Molecular studies demonstrated that the mechanism of stimulation was not secondary to altered BBM SGLT1 protein levels. Chronic and direct silencing of basolateral Na-K-ATPase uniquely regulates BBM Na absorptive pathways in intestinal epithelial cells. Specifically, while BBM NHE3 is unaffected, SGLT1 is stimulated secondary to enhanced affinity of the cotransporter.

  16. Growth and electronic properties of NaCl on HOPG

    NASA Astrophysics Data System (ADS)

    Mahapatra, O.; Kowalczyk, P. J.; Brown, S. A.

    2014-02-01

    We report the growth of cross-shaped islands of NaCl on highly oriented pyrolytic graphite (HOPG) and discuss the mechanism of formation and growth kinetics within the framework of diffusion limited aggregation (DLA). These structures are investigated using scanning probe microscopy. The shape and structure of these islands can be finely controlled by the deposition conditions. The islands exhibit large atomically flat surfaces which are ideal supports for investigations of the fundamental properties of deposited atoms, molecules or clusters. Bismuth nanostructures were deposited on the NaCl islands and were investigated via scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). The tunneling spectra recorded for particles on NaCl are surprisingly similar to those measured for similar particles on HOPG. We suggest that this is due to a 'dead' layer commonly observed for Bi thin films.

  17. Superconducting properties and electronic structure of NaBi.

    PubMed

    Kushwaha, S K; Krizan, J W; Xiong, J; Klimczuk, T; Gibson, Q D; Liang, T; Ong, N P; Cava, R J

    2014-05-28

    Resistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. T(c), the electronic contribution to the specific heat γ, the ΔC(p)/γT(c) ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol(-1) K(-2), 0.78, and 140 K respectively. The calculated electron-phonon coupling constant (λ(ep) = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence length are found to be 250 Oe and 115 nm, respectively. Electronic structure calculations show NaBi to be a good metal, in agreement with the experiments; the p(x) and p(y) orbitals of Bi dominate the electronic states at the Fermi Energy. PMID:24804822

  18. HARP and NA61 (SHINE) hadron production experiments

    SciTech Connect

    Popov, Boris A.

    2009-11-25

    The hadroproduction experiments HARP and NA61 (SHINE) as well as their implications for neutrino physics are discussed. Recent HARP measurements have already been used for precise predictions of neutrino beams in K2K and MiniBooNE/SciBooNE experiments and are also being used to improve the atmospheric neutrino flux predictions and to help in the optimization of neutrino factory and super-beam designs. First preliminary data from NA61 are of significant importance for a precise prediction of a new neutrino beam at J-PARC to be used for the first stage of the T2K experiment. Both HARP and NA61 provide a large amount of input for validation and tuning of hadroproduction models in Monte-Carlo generators.

  19. Superconducting properties and electronic structure of NaBi.

    PubMed

    Kushwaha, S K; Krizan, J W; Xiong, J; Klimczuk, T; Gibson, Q D; Liang, T; Ong, N P; Cava, R J

    2014-05-28

    Resistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. T(c), the electronic contribution to the specific heat γ, the ΔC(p)/γT(c) ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol(-1) K(-2), 0.78, and 140 K respectively. The calculated electron-phonon coupling constant (λ(ep) = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence length are found to be 250 Oe and 115 nm, respectively. Electronic structure calculations show NaBi to be a good metal, in agreement with the experiments; the p(x) and p(y) orbitals of Bi dominate the electronic states at the Fermi Energy.

  20. A pore segment in DEG/ENaC Na(+) channels.

    PubMed

    Snyder, P M; Olson, D R; Bucher, D B

    1999-10-01

    DEG/ENaC Na(+) channels have diverse functions, including Na(+) absorption, neurotransmission, and sensory transduction. The ability of these channels to discriminate between different ions is critical for their normal function. Several findings suggest that DEG/ENaC channels have a pore structure similar to K(+) channels. To test this hypothesis, we examined the accessibility of native and introduced cysteines in the putative P loop of ENaC. We identified residues that span a barrier that excludes amiloride as well as anionic and large methanethiosulfonate reagents from the pore. This segment contains a structural element ((S/G)CS) involved in selectivity of ENaC. The results are not consistent with predictions from the K(+) channel pore, suggesting that DEG/ENaC Na(+) channels have a novel pore structure. PMID:10497211

  1. Na3Al(AsO4)2

    PubMed Central

    Fakhar Bourguiba, Noura; Zid, Mohamed Faouzi; Driss, Ahmed

    2013-01-01

    The structure of the title compound tris­odium aluminium bis­(arsenate), Na3Al(AsO4)2, is built up from AlO4 and AsO4 corner-sharing tetra­hedra, forming an undulating two-dimensional framework parallel to (100). The layers are constituted of large Al6As6O36 rings made up from six AlO4 and AsO4 tetra­hedra in which two sodium cations are situated, the third sodium cation being located in the inter­layer space. The structural relationships between the title compound and Na3Fe(PO4)2, NaAlCo(PO4)2 and Al5Co3(PO4)8 are discussed. PMID:23424394

  2. Binding energy and structure of e{sup +}Na

    SciTech Connect

    Shertzer, J.; Ward, S. J.

    2010-06-15

    We calculate the nonadiabatic binding energy and geometry of the weakly bound state of e{sup +}Na. We use the Peach model potential, which includes both the dipole and an effective quadrupole term in the polarization, to describe the interaction of the electron and positron with the ion core. The effective three-body Schroedinger equation is solved with the finite element method. Because the model potential gives rise to three spurious states, the true ground state of e{sup +}Na is embedded in a dense spectrum of spurious states. We develop a method for extracting the correct ground state for e{sup +}Na, even when the energy is nearly degenerate with a spurious level. The calculated value for the binding energy is consistent with other calculations.

  3. Role of Na+ and K+ in enzyme function.

    PubMed

    Page, Michael J; Di Cera, Enrico

    2006-10-01

    Metal complexation is a key mediator or modifier of enzyme structure and function. In addition to divalent and polyvalent metals, group IA metals Na+ and K+ play important and specific roles that assist function of biological macromolecules. We examine the diversity of monovalent cation (M+)-activated enzymes by first comparing coordination in small molecules followed by a discussion of theoretical and practical aspects. Select examples of enzymes that utilize M+ as a cofactor (type I) or allosteric effector (type II) illustrate the structural basis of activation by Na+ and K+, along with unexpected connections with ion transporters. Kinetic expressions are derived for the analysis of type I and type II activation. In conclusion, we address evolutionary implications of Na+ binding in the trypsin-like proteases of vertebrate blood coagulation. From this analysis, M+ complexation has the potential to be an efficient regulator of enzyme catalysis and stability and offers novel strategies for protein engineering to improve enzyme function.

  4. The stability of sodalite in the system NaAlSiO sub 4 -NaCl

    SciTech Connect

    Sharp, Z.D. ); Helffrich, G.R. ); Bohlen, S.R. ); Essene, E.J. )

    1989-08-01

    The reaction sodalite = {beta}-nepheline + NaCl (s) was reversed in solid-medium apparatus and the reaction sodalite = carnegieite + NaCl (l) was reversed at 1 bar (1,649-1,652 K). The experimental reversals between 923 K and 973 K can be fit with a dP/dT of {minus}11 bar/K, suggesting that the excess entropy for sodalite is present only above 923 K. A phase diagram for the NaAlSiO{sub 4}-NaCl system that is consistent with the measured thermochemical data and the experiments between 973 and 1,650 K can be generated if the 61.7 J/mol{center dot}K entropy contribution is included in the S{sup 0}{sub 298} of sodalite. This entropy contribution must be removed below 973 K for the experiments to fit with calculations. Previously unreported thermodynamic data estimated in this study are {Delta}G{sup 0}{sub 298} for sodalite ({minus}12,697 kJ/mol) and carnegieite (NaAlSiO{sub 4}) ({minus}1,958 kJ/mol), S{sup 0}{sub 298} of carnegieite (129.6 J/mol{center dot}K) and compressibility of NaCl{sub liquid} (V{sup P}{sub 298} (cm{sup 3}) = 31.6{center dot}(1 - 24.7{center dot}10{sup {minus}3}{center dot}P + 800{center dot}10{sup {minus}6}{center dot}P{sup 2}))(T in K; P in kbar). Sodalite is a high-temperature, low-pressure phase, stable well above the solidus in sodic silica-undersaturated magmas enriched in NaCl, and its presence constrains NaCl activities in magmas. Estimates of minimum NaCl (l) activities in the Mont St-Hilaire sodalite syenites are 0.05 at 1,073 K and 0.13 at 1,273 K. Density calculations are consistent with the field observations that sodalite phenocrysts will float in a nepheline syenite liquid. This explains the enrichment of sodalite in the upper levels of the sodalite syenites at Mont St.Hilaire and elsewhere.

  5. Rate-Dependent Nucleation and Growth of NaO2 in Na-O2 Batteries.

    PubMed

    Ortiz-Vitoriano, Nagore; Batcho, Thomas P; Kwabi, David G; Han, Binghong; Pour, Nir; Yao, Koffi Pierre Claver; Thompson, Carl V; Shao-Horn, Yang

    2015-07-01

    Understanding the oxygen reduction reaction kinetics in the presence of Na ions and the formation mechanism of discharge product(s) is key to enhancing Na-O2 battery performance. Here we show NaO2 as the only discharge product from Na-O2 cells with carbon nanotubes in 1,2-dimethoxyethane from X-ray diffraction and Raman spectroscopy. Sodium peroxide dihydrate was not detected in the discharged electrode with up to 6000 ppm of H2O added to the electrolyte, but it was detected with ambient air exposure. In addition, we show that the sizes and distributions of NaO2 can be highly dependent on the discharge rate, and we discuss the formation mechanisms responsible for this rate dependence. Micron-sized (∼500 nm) and nanometer-scale (∼50 nm) cubes were found on the top and bottom of a carbon nanotube (CNT) carpet electrode and along CNT sidewalls at 10 mA/g, while only micron-scale cubes (∼2 μm) were found on the top and bottom of the CNT carpet at 1000 mA/g, respectively.

  6. Plant response to Na/sup +/, K/sup +/ and K/sup +//Na/sup +/ ratios under saline conditions

    SciTech Connect

    Devitt, D.A.

    1983-01-01

    This research was undertaken to more clearly determine plant response to saline-sodic waters. In the first experiment, the response of wheat and sorghum to different K/sup +//Na/sup +/ ratios at different osmotic potentials was investigated. The plants were grown in outdoor solution culture tanks containing polyethylene glycol and/or NaCl as osmoticum with 1/2 strength Hoagland as the base nutrient solution. The mass of the root system for both wheat and sorghum was determined primarily by the osmotic potential. However, root elongation was controlled primarily by the Na/sup +/ concentration. Sorghum root elongation rates decreased with increasing Na/sup +/ while those for wheat increased. Sodium was not translocated out of the sorghum root system until a critical Na/sup +/ root saturation level of .6 moles/kg was obtained. The second experiment was designed to investigate the water, nutrient and growth responses of the second crop of wheat in a wheat-sorghum-wheat rotation to zonal saline-sodic conditions.

  7. Rate-Dependent Nucleation and Growth of NaO2 in Na-O2 Batteries.

    PubMed

    Ortiz-Vitoriano, Nagore; Batcho, Thomas P; Kwabi, David G; Han, Binghong; Pour, Nir; Yao, Koffi Pierre Claver; Thompson, Carl V; Shao-Horn, Yang

    2015-07-01

    Understanding the oxygen reduction reaction kinetics in the presence of Na ions and the formation mechanism of discharge product(s) is key to enhancing Na-O2 battery performance. Here we show NaO2 as the only discharge product from Na-O2 cells with carbon nanotubes in 1,2-dimethoxyethane from X-ray diffraction and Raman spectroscopy. Sodium peroxide dihydrate was not detected in the discharged electrode with up to 6000 ppm of H2O added to the electrolyte, but it was detected with ambient air exposure. In addition, we show that the sizes and distributions of NaO2 can be highly dependent on the discharge rate, and we discuss the formation mechanisms responsible for this rate dependence. Micron-sized (∼500 nm) and nanometer-scale (∼50 nm) cubes were found on the top and bottom of a carbon nanotube (CNT) carpet electrode and along CNT sidewalls at 10 mA/g, while only micron-scale cubes (∼2 μm) were found on the top and bottom of the CNT carpet at 1000 mA/g, respectively. PMID:26266746

  8. Comparison of the Na(4p) + H2 and Na(3p) + H2 reactive/quenching systems studied with CARS, resonance-enhanced CARS, and DFWM

    NASA Astrophysics Data System (ADS)

    Motzkus, M.; Pichler, G.; Kompa, K. L.; Hering, P.

    1997-06-01

    Three different nonlinear optical techniques, CARS (coherent anti-Stokes Raman scattering), resonance-enhanced CARS, and DFWM (degenerate four-wave mixing), were used to compare the reactive and quenching behavior of the two different electronically excited sodium atoms, Na(3p) and Na(4p), in a collision with H2. In the chemical reaction channel both excited sodium states produce NaH molecules, but in the case of Na(3p) it is shown that the reaction is not a direct formation process and involves more than one step. Both sodium states induce a population of the vibrational levels v″=0-3 of NaH. For the Na(3p) excitation the population of the NaH molecules is concentrated at v″=0, whereas for the excitation of the Na(4p) state NaH has its maximum population in the v″=1 level. The differences are attributed to different potential energy surfaces. The quenching investigations were focused on the behavior of the Na(4p) state and the results were compared with the well-known behavior of the Na(3p) state. Because no quenching products were detected in the CARS spectra with Na(4p) excitation, the upper limit for the integrated quenching cross section was estimated to be less than 5×10-17 cm2, as based on the detection sensitivity of the CARS apparatus.

  9. Pancreatic β-cell Na+ channels control global Ca2+ signaling and oxidative metabolism by inducing Na+ and Ca2+ responses that are propagated into mitochondria.

    PubMed

    Nita, Iulia I; Hershfinkel, Michal; Kantor, Chase; Rutter, Guy A; Lewis, Eli C; Sekler, Israel

    2014-08-01

    Communication between the plasma membrane and mitochondria is essential for initiating the Ca(2+) and metabolic signals required for secretion in β cells. Although voltage-dependent Na(+) channels are abundantly expressed in β cells and activated by glucose, their role in communicating with mitochondria is unresolved. Here, we combined fluorescent Na(+), Ca(2+), and ATP imaging, electrophysiological analysis with tetrodotoxin (TTX)-dependent block of the Na(+) channel, and molecular manipulation of mitochondrial Ca(2+) transporters to study the communication between Na(+) channels and mitochondria. We show that TTX inhibits glucose-dependent depolarization and blocks cytosolic Na(+) and Ca(2+) responses and their propagation into mitochondria. TTX-sensitive mitochondrial Ca(2+) influx was largely blocked by knockdown of the mitochondrial Ca(2+) uniporter (MCU) expression. Knockdown of the mitochondrial Na(+)/Ca(2+) exchanger (NCLX) and Na(+) dose response analysis demonstrated that NCLX mediates the mitochondrial Na(+) influx and is tuned to sense the TTX-sensitive cytosolic Na(+) responses. Finally, TTX blocked glucose-dependent mitochondrial Ca(2+) rise, mitochondrial metabolic activity, and ATP production. Our results show that communication of the Na(+) channels with mitochondria shape both global Ca(2+) and metabolism signals linked to insulin secretion in β cells.- Nita, I. I., Hershfinkel, M., Kantor, C., Rutter, G. A., Lewis, E. C., Sekler, I. Pancreatic β-cell Na(+) channels control global Ca(2+) signaling and oxidative metabolism by inducing Na(+) and Ca(2+) responses that are propagated into mitochondria.

  10. Na+ conductivity of the Na+-driven flagellar motor complex composed of unplugged wild-type or mutant PomB with PomA.

    PubMed

    Takekawa, Norihiro; Terauchi, Takashi; Morimoto, Yusuke V; Minamino, Tohru; Lo, Chien-Jung; Kojima, Seiji; Homma, Michio

    2013-05-01

    PomA and PomB form the stator complex, which functions as a Na(+) channel, in the Na(+)-driven flagellar motor of Vibrio alginolyticus. The plug region of PomB is thought to regulate the Na(+) flow and to suppress massive ion influx through the stator channel. In this study, in order to measure the Na(+) conductivity of the unplugged stator, we over-produced a plug-deleted stator of the Na(+)-driven flagellar motor in Escherichia coli. The over-production of the plug-deleted stator in E. coli cells caused more severe growth inhibition than in Vibrio cells and that growth inhibition depended on the Na(+) concentration in the growth medium. Measurement of intracellular Na(+) concentration by flame photometry and fluorescent analysis with a Na(+) indicator, Sodium Green, revealed that over-production of the plug-deleted stator increased the Na(+) concentration in cell. Some mutations in the channel region of PomB or in the cytoplasmic region of PomA suppressed both the growth inhibition and the increase in intracellular Na(+) concentration. These results suggest that the level of growth inhibition correlates with the intracellular Na(+) concentration, probably due to the Na(+) conductivity through the stator due to the mutations. PMID:23420849

  11. A new low-voltage plateau of Na3V2(PO4)(3) as an anode for Na-ion batteries

    SciTech Connect

    Jian, ZL; Sun, Y; Ji, XL

    2015-01-01

    A low-voltage plateau at similar to 0.3 V is discovered for the deep sodiation of Na3V2(PO4)(3) by combined computational and experimental studies. This new low-voltage plateau doubles the sodiation capacity of Na3V2(PO4)(3), thus turning it into a promising anode for Na-ion batteries.

  12. Genetic Architecture of NaCl Tolerance in Arabidopsis1

    PubMed Central

    Quesada, Víctor; García-Martínez, Santiago; Piqueras, Pedro; Ponce, María Rosa; Micol, José Luis

    2002-01-01

    The little success of breeding approaches toward the improvement of salt tolerance in crop species is thought to be attributable to the quantitative nature of most, if not all the processes implicated. Hence, the identification of some of the quantitative trait loci (QTL) that contribute to natural variation in salt tolerance should be instrumental in eventually manipulating the perception of salinity and the corresponding responses. A good choice to reach this goal is the plant model system Arabidopsis, whose complete genome sequence is now available. Aiming to analyze natural variability in salt tolerance, we have compared the ability of 102 wild-type races (named ecotypes or accessions) of Arabidopsis to germinate on 250 mm NaCl, finding a wide range of variation among them. Accessions displaying extremely different responses to NaCl were intercrossed, and the phenotypes found in their F2 progenies suggested that natural variation in NaCl tolerance during germination was under polygenic controls. Genetic distances calculated on the basis of variations in repeat number at 22 microsatellites, were analyzed in a group of either extremely salt-tolerant or extremely salt-sensitive accessions. We found that most but not all accessions with similar responses to NaCl are phylogenetically related. NaCl tolerance was also studied in 100 recombinant inbred lines derived from a cross between the Columbia-4 and Landsberg erecta accessions. We detected 11 QTL harboring naturally occurring alleles that contribute to natural variation in NaCl tolerance in Arabidopsis, six at the germination and five at the vegetative growth stages, respectively. At least five of these QTL are likely to represent loci not yet described by their relationship with salt stress. PMID:12376659

  13. [Effects of NaCl stress on cation contents in different pumpkin cultivars' seedlings].

    PubMed

    Li, Wei-Xin; Chen, Gui-Lin; Ren, Liang-Yu; Wang, Peng

    2008-03-01

    With the seedlings of 19 pumpkin cultivars as test materials, this paper studied the variations of Na+, K+, Ca2+, Na+/K+, Na+/Ca2+, SN+, K+ and SNa+, ca2+ in their shoots and roots under the stress of 300 mmol NaCl x L(-1). The results showed that after an 8-day exposure to 300 mmol NaCl x L(-1), the Na+ content in the seedlings increased significantly while the K+ content decreased, resulting in the brokenness of ion balance. The root Na+ content, shoot Na+/K+ and Na+/Ca2+ ratios, and SNa+, K+ and SNa+, Ca2+ of Cucurbita moschata (Q1) were significantly higher than those of C. maxima (H2) and C. ficifolia (H3). The variation tendency of these parameters of different pumpkin cultivars' seedlings were nearly consistent with the salt injury index of the seedlings under NaCl stress, which further proved that the strong salt-tolerance of Q1 was related to the lower values of shoot Na+/K+, Na+/Ca2+, SNa+, K+ and SNa+, Ca2+, and the high contents of K+ and Ca2+, while the salt-sensitivity of H2 and H3 was related to the higher values of shoot Na+/K+, Na+/Ca2+, SNa+, K+ and SNa+, Ca2+, and low contents of K+ and Ca2+ under NaCl stress.

  14. Brain Na+, K+-ATPase Activity In Aging and Disease

    PubMed Central

    de Lores Arnaiz, Georgina Rodríguez; Ordieres, María Graciela López

    2014-01-01

    Na+/K+ pump or sodium- and potassium-activated adenosine 5’-triphosphatase (Na+, K+-ATPase), its enzymatic version, is a crucial protein responsible for the electrochemical gradient across the cell membranes. It is an ion transporter, which in addition to exchange cations, is the ligand for cardenolides. This enzyme regulates the entry of K+ with the exit of Na+ from cells, being the responsible for Na+/K+ equilibrium maintenance through neuronal membranes. This transport system couples the hydrolysis of one molecule of ATP to exchange three sodium ions for two potassium ions, thus maintaining the normal gradient of these cations in animal cells. Oxidative metabolism is very active in brain, where large amounts of chemical energy as ATP molecules are consumed, mostly required for the maintenance of the ionic gradients that underlie resting and action potentials which are involved in nerve impulse propagation, neurotransmitter release and cation homeostasis. Protein phosphorylation is a key process in biological regulation. At nervous system level, protein phosphorylation is the major molecular mechanism through which the function of neural proteins is modulted in response to extracellular signals, including the response to neurotransmitter stimuli. It is the major mechanism of neural plasticity, including memory processing. The phosphorylation of Na+, K+-ATPase catalytic subunit inhibits enzyme activity whereas the inhibition of protein kinase C restores the enzyme activity. The dephosphorylation of neuronal Na+, K+-ATPase is mediated by calcineurin, a serine / threonine phosphatase. The latter enzyme is involved in a wide range of cellular responses to Ca2+ mobilizing signals, in the regulation of neuronal excitability by controlling the activity of ion channels, in the release of neurotransmitters and hormones, as well as in synaptic plasticity and gene transcription. In the present article evidence showing Na+, K+-ATPase involvement in signaling pathways

  15. Optically stimulated luminescence in doped NaCl

    NASA Astrophysics Data System (ADS)

    Gaikwad, S. U.; Patil, R. R.; Kulkarni, M. S.; Bhatt, B. C.; Moharil, S. V.

    2016-05-01

    NaCl:Ca,Cu,P NaCl:Mg,Cu,P OSL phosphors are synthesized. Intense OSL is observed in these samples which is 14 times more than Al2O3:C. Same samples coated with PVA (poly vinyl actetae) polymer also show similar OSL properties and these coated samples are found to be less susceptible to the moisture due to protected layer of hydrophobic polymer. These coated samples may be useful as OSL dosimetersdue to high sensitivity and less or no susceptibility to moisture.

  16. Possible selective adsorption of enantiomers by Na-montmorillonite

    NASA Technical Reports Server (NTRS)

    Friebele, E.; Shimoyama, A.; Ponnamperuma, C.

    1981-01-01

    Racemic amino acids including (D,L) alpha-alamine, (D,L) alpha-aminobutyric acid, (D,L) valine, and (D,L) norvaline were incubated with Na-montmorillonite at 100% CEC at three hydrogen ion concentrations, and amino acid adsorption was determined by ion exchange chromatography. Enantiomers were analyzed by gas chromatography. Differences in the quantities of D and L enantiomers in any of the fractions was no larger than a few percent. Although a large difference in the adsorption of the amino acid enantiomers was not observed, the analysis may indicate a small preferential adsorption (0.5-2%) of L-amino acids by Na-montmorillonite.

  17. Measurements of electric discharge characteristics in NaCl solution

    NASA Astrophysics Data System (ADS)

    Ablesimov, V. E.; Karyuk, V. M.; Pavlov, A. N.; Kirpichev, A. A.; Simchuk, A. A.

    2015-03-01

    The characteristics of electric discharge in a NaCl solution with a specific concentration of up to ˜1.7% (electrical conductivity up to 0.032 Sm/cm) are investigated. The discharge is produced by the Era-1 discharger in a vessel filled with water or a NaCl solution. We obtain the dependences of the maximal discharge current, pressure pulse, and the pressure amplitude at the shock front at a distance of 7 cm from the discharge axis on the electrolyte concentration.

  18. Russian Scientific-Educational Project: Kazan-GeoNa-2017

    NASA Astrophysics Data System (ADS)

    Gusev, A.; Alibekova, N.

    2012-09-01

    For the further successful development of educational and scientific - educational activity of the Russian Federation, the Republic Tatarstan, Kazan is offered the national project - the International Center of the Science and the Internet of Technologies. "GeoNa" (Geometry of Nature - "GeoNa" is developed - wisdom, enthusiasm, pride, grandeur), which includes a modern complex of conference halls (up to 4 thousand places), the Center the Internet of Technologies, 3D Planetarium - development of the Moon, PhysicsLand, an active museum of natural sciences, an oceanarium, training a complex «Spheres of Knowledge», botanical and landscape oases.

  19. Structural Integrity and Microstructure of NA^+ Conducting Ceramics

    NASA Astrophysics Data System (ADS)

    Lipinska, Kristina; Kalita, Patricia; Hemmers, Oliver; Sinogeikin, Stanislav; Shebanova, Olga; Yang, Wenge; Mariotto, Gino

    2010-03-01

    Oxides with the general formula of Na1+x Zr2 Six P3-x O12 , known as Nasicon, are fast Na+ ion-conducting materials with important electrochemical applications and many functional properties, often attributed to their unique structural features. Comparative, in situ studies of the limits of structural integrity were performed for selected Nasicon materials, using synchrotron x-ray diffraction and diamond anvil cell technology. We show how different processing conditions produce crystalline structures with specific morphology. We discuss the bulk modulus, the compressibility and the influence of the volume fraction of primary and secondary crystalline phases on the overall Nasicon structural integrity.

  20. Regulation of cough by neuronal Na(+)-K(+) ATPases.

    PubMed

    Canning, Brendan J; Farmer, David G S

    2015-06-01

    The Na(+)-K(+) ATPases play an essential role in establishing the sodium gradients in excitable cells. Multiple isoforms of the sodium pumps have been identified, with tissue and cell specific expression patterns. Because the vagal afferent nerves regulating cough must be activated at sustained high frequencies of action potential patterning to achieve cough initiation thresholds, it is a certainty that sodium pump function is essential to maintaining cough reflex sensitivities in health and in disease. The mechanisms by which Na(+)-K(+) ATPases regulate bronchopulmonary vagal afferent nerve excitability are reviewed as are potential therapeutic strategies targeting the sodium pumps in cough.

  1. Toward Triplet Ground State NaLi Molecules

    NASA Astrophysics Data System (ADS)

    Ebadi, Sepehr; Jamison, Alan; Rvachov, Timur; Jing, Li; Son, Hyungmok; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

    2016-05-01

    The NaLi molecule is expected to have a long lifetime in the triplet ground-state due to its fermionic nature, large rotational constant, and weak spin-orbit coupling. The triplet state has both electric and magnetic dipole moments, affording unique opportunities in quantum simulation and ultracold chemistry. We have mapped the excited state NaLi triplet potential by means of photoassociation spectroscopy. We report on this and our further progress toward the creation of the triplet ground-state molecules using STIRAP. NSF, ARO-MURI, Samsung, NSERC.

  2. Efficiency of the Modular Neutron Array (MoNA)

    NASA Astrophysics Data System (ADS)

    Peters, W. A.; Baumann, T.; Christian, G. A.; Denby, D.; DeYoung, P. A.; Finck, J. E.; Frank, N.; Hall, C. C.; Hinnefeld, J.; Schiller, A.; Strongman, M. J.; Thoennessen, M.

    2009-03-01

    The efficiency of the Modular Neutron Array (MoNA), located at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University, was measured and compared to simulations. The Coulomb dissociation of a 90 MeV/u beam of 11Be in a gold target was used to produce neutrons. The expected neutron production rate was calculated using the virtual photon method. The measured efficiency agrees with the efficiency calculated with GEANT simulations. The current configuration of MoNA has a 73% intrinsic detection efficiency for 90 MeV neutrons.

  3. Study of resonant scattering of 21Na+p relevant to astrophysical 18Ne(α,p)21Na reaction

    NASA Astrophysics Data System (ADS)

    He, J. J.; Zhang, L. Y.; Xu, S. W.; Chen, S. Z.; Hu, J.; Ma, P.; Chen, R. F.; Yamaguchi, H.; Kubono, S.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Wakabayashi, Y.; Togano, Y.; Wang, H. W.; Tian, W. D.; Guo, B.; Teranishi, T.; Iwasa, N.; Yamada, T.; Komatsubara, T.

    2012-11-01

    Astrophysical 18Ne(α,p)21Na reaction is one of the most probable breakout routes, which lead to the rp-process from the hot-CNO cycle, converting the initial CNO elements into heavier elements in Type I x-ray bursters. Presently, there is no much experimental cross-section data reported at the energy of astrophysical interest, and resonant spectroscopic information in compound 22Mg is scarce as well. The experiment has been carried out by using the CNS radioactive ion beam separator (CRIB). Resonant properties in 22Mg have been studied via the resonant elastic scattering of 21Na+p, and cross section of the time-reversal reaction of 21Na(p,α)18Ne been measured simultaneously. A wide excitation energy region up to Ex ~ 9.5 MeV in 22Mg has been scanned with a thick-target method. Some preliminary results will be reported.

  4. Toward a cold hybrid-trap measurement of charge-exchange between Na and Ca+: Na excited state fraction

    NASA Astrophysics Data System (ADS)

    Wells, James E.; Goodman, Douglas S.; Kwolek, Jonathan M.; Blumel, Reinhold; Narducci, Frank A.; Smith, Winthrop W.

    2015-05-01

    We present progress towards the measurement of the charge-exchange collision rate coefficient between neutral sodium and ionic calcium. The rate constant for charge exchange between ground state sodium and calcium ion has been previously calculated and predicts a lifetime in our system of the order of days. Experiments by our group show a much larger charge exchange collision rate, probably from the excited 3P state of sodium. Therefore, an accurate measurement of the charge exchange collision rate constant will require an accurate value for the excited state fraction of the Na MOT. We have developed a technique for making a model-independent measurement of the excited state fraction of a MOT inside a hybrid trap. We compare the measured excited state fraction using this technique with measurements assuming a two-level model of the atom. In addition, we review our recent measurement of the total elastic and resonant charge exchange collision rate between Na and Na+.

  5. Na+-dependent and Na+-independent betaine transport across the apical membrane of rat renal epithelium.

    PubMed

    Cano, Mercedes; Calonge, María L; Ilundáin, Anunciación A

    2015-10-01

    The low renal excretion of betaine indicates that the kidney efficiently reabsorbs the betaine filtered by the glomeruli but the mechanisms involved in such a process have been scarcely investigated. We have detected concentrative and non-concentrative betaine transport activity in brush-border membrane vesicles (BBMV) from rat renal cortex and medulla. The concentrative system is the Sodium/Imino-acid Transporter 1 (SIT1) because it is Na+- and Cl--dependent, electrogenic and is inhibited by an anti-SIT1 antibody. Its apparent affinity constant for betaine, Kt, is 1.1±0.5 mM and its maximal transport velocity, Vmax, 0.5±0.1 nmol betaine/mg protein/s. Inhibitors of the Na+/Cl-/betaine uptake are L-proline (75%) and cold betaine, L-carnitine and choline (40-60%). Neither creatine, TEA, taurine, β-alanine, GABA nor glycine significantly inhibited Na+/Cl-/betaine uptake. The non-concentrative betaine transport system is Na+- and H+-independent, electroneutral, with a Kt for betaine of 47±7 μM and a Vmax of 7.8±1 pmol betaine/mg protein/s. Its transport activity is nearly abolished by betaine, followed by L-carnitine (70-80%) and proline (40-50%), but a difference from the Na+/Cl-/betaine transport is that it is inhibited by TEA (approx. 50%) and unaffected by choline. The underlying carrier functions as an antiporter linking betaine entry into the BBMV with the efflux of either L-carnitine or betaine, an exchange unaffected by the anti-SIT1 antibody. As far as we know this is the first work reporting that betaine crosses the apical membrane of rat renal epithelium by SIT1 and by a Na+- and H+-independent transport system.

  6. Physiological interactions between Na(v)1.7 and Na(v)1.8 sodium channels: a computer simulation study.

    PubMed

    Choi, Jin-Sung; Waxman, Stephen G

    2011-12-01

    We have examined the question of how the level of expression of sodium channel Na(v)1.8 affects the function of dorsal root ganglion (DRG) neurons that also express Na(v)1.7 channels and, conversely, how the level of expression of sodium channel Na(v)1.7 affects the function of DRG neurons that also express Na(v)1.8, using computer simulations. Our results demonstrate several previously undescribed effects of expression of Na(v)1.7: 1) at potentials more negative than -50 mV, increasing Na(v)1.7 expression reduces current threshold. 2) Na(v)1.7 reduces, but does not eliminate, the dependence of action potential (AP) threshold on membrane potential. 3) In cells that express Na(v)1.8, the presence of Na(v)1.7 results in larger amplitude subthreshold oscillations and increases the frequency of repetitive firing. Our results also demonstrate multiple effects of expression of Na(v)1.8: 1) dependence of current threshold on membrane potential is eliminated or reversed by expression of Na(v)1.8 at ≥50% of normal values. 2) Expression of Na(v)1.8 alone, in the absence of Na(v)1.7, can support subthreshold oscillation. 3) Na(v)1.8 is required for generation of overshooting APs, and its expression results in a prolonged AP with an inflection of the falling phase. 4) Increasing levels of expression of Na(v)1.8 result in a reduction in the voltage threshold for AP generation. 5) Increasing levels of expression of Na(v)1.8 result in an attenuation of Na(v)1.7 current during activity evoked by sustained depolarization due, at least in part, to accumulation of fast inactivation by Na(v)1.7 following the first AP. These results indicate that changes in the level of expression of Na(v)1.7 and Na(v)1.8 may provide a regulatory mechanism that tunes the excitability of small DRG neurons. PMID:21940606

  7. Magnetic properties of ternary sodium oxides Na LnO 2 ( Ln=rare earths)

    NASA Astrophysics Data System (ADS)

    Hashimoto, Yuta; Wakeshima, Makoto; Hinatsu, Yukio

    2003-11-01

    Magnetic properties of ternary sodium oxides Na LnO 2 ( Ln=rare earths) are investigated. Their crystal structures are grouped into three types of structures, which are α-LiFeO 2, β-LiFeO 2, and α-NaFeO 2, depending on the size of rare earths. Their magnetic susceptibilities and specific heats have been measured from 1.8 to 300 K. Among them, NaGdO 2, NaDyO 2, and NaHoO 2 show antiferromagnetic transitions at 2.4, 2.2, and 2.4 K, respectively, and NaNdO 2 transforms to the ferromagnetic state below 2.4 K. NaSmO 2, NaErO 2, and NaYbO 2 exhibit a magnetic anomaly below 1.8 K.

  8. Stainless Steel NaK Circuit Integration and Fill Submission

    NASA Technical Reports Server (NTRS)

    Garber, Anne E.

    2006-01-01

    The Early Flight Fission Test Facilities (EFF-TF) team has been tasked by the Marshall Space Flight Center Nuclear Systems Office to design, fabricate, and test an actively pumped alkali metal flow circuit. The system, which was originally designed to hold a eutectic mixture of sodium potassium (NaK), was redesigned to hold lithium; but due to a shift in focus, it is once again being prepared for use with NaK. Changes made to the actively pumped, high temperature loop include the replacement of the expansion reservoir, addition of remotely operated valves, and modification of the support table. Basic circuit components include: reactor segment, NaK to gas heat exchanger, electromagnetic (EM) liquid metal pump, load/drain reservoir, expansion reservoir, instrumentation, and a spill reservoir. A 37-pin partial-array core (pin and flow path dimensions are the same as those in a full design) was selected for fabrication and test. This document summarizes the integration and fill of the pumped liquid metal NaK flow circuit.

  9. Substituting KCl for NaCl in fresh Queso Fresco

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing the sodium level in cheese is challenging when a signature salty flavor is expected, such as in high-moisture Queso Fresco (QF). Fresh starter-free QF was fine milled and dry salted at different levels of NaCl and KCl to obtain total salt levels of 1.5 to 2.0%. The treatments contained 1....

  10. Rechargeable Room-Temperature Na-CO2 Batteries.

    PubMed

    Hu, Xiaofei; Sun, Jianchao; Li, Zifan; Zhao, Qing; Chen, Chengcheng; Chen, Jun

    2016-05-23

    Developing rechargeable Na-CO2 batteries is significant for energy conversion and utilization of CO2 . However, the reported batteries in pure CO2 atmosphere are non-rechargeable with limited discharge capacity of 200 mAh g(-1) . Herein, we realized the rechargeability of a Na-CO2 battery, with the proposed and demonstrated reversible reaction of 3 CO2 +4 Na↔2 Na2 CO3 +C. The battery consists of a Na anode, an ether-based electrolyte, and a designed cathode with electrolyte-treated multi-wall carbon nanotubes, and shows reversible capacity of 60000 mAh g(-1) at 1 A g(-1) (≈1000 Wh kg(-1) ) and runs for 200 cycles with controlled capacity of 2000 mAh g(-1) at charge voltage <3.7 V. The porous structure, high electro-conductivity, and good wettability of electrolyte to cathode lead to reduced electrochemical polarization of the battery and further result in high performance. Our work provides an alternative approach towards clean recycling and utilization of CO2 .

  11. Separating Silicon From Si/NaF Mixtures

    NASA Technical Reports Server (NTRS)

    Sanjurjo, A.; Nanis, L.

    1982-01-01

    New method of extracting silicon from mixture produced when silicon tetrafluoride is reduced by sodium takes advantage of lower melting point of NaF. Method is effective at temperatures up to 400 degrees C below melting point of Si. Results in energy and economic savings: simpler and smaller furnaces, less volatization loss, and high percentage of separation.

  12. Ultraweak bioluminescence of maize under NaCl stress

    NASA Astrophysics Data System (ADS)

    Xie, Zhaohui

    2009-11-01

    In this paper, the delayed ultra-weak luminescence (UWL), leaf dry/fresh weight and reactive oxygen species (ROS) of the maize (Jundan 20) were investigated under various NaCl concentration. The results showed that following with the increase of NaCl, ROS contents increased obviously, but the UWL intensity decreased, and the decrease speed increased following with the increase of NaCl concentration, the decrease extent of delayed luminescence ranged from 10.4% to 27.2%. It was also found that both dry and fresh weight of seedling leaves decreased, but the ratio of dry/fresh weight increased. According to these results, we speculated that the decrease of UWL was mainly closely associated with the destruction of seedling normal physiological activities and metabolic disorder which were caused by NaCl stress, rather than ROS only. This study revealed that the spectral analysis of UWL is a useful tool for studying plant response to salt stress.

  13. Bilingual Education at Dzil Na'oodilii Community School.

    ERIC Educational Resources Information Center

    Howard, Roy E.

    Proceedings of a Navajo Bilingual Education Conference held April 26 and 27, 1985, are summarized in this report which focuses on the implementation of Navajo language and cultural education at the Dzlith Na O Dith Hle Community School (DCS). The paper begins by stating that the conference was intended to assist educators in understanding and…

  14. Neutral Na in comets tails: a chemical story

    NASA Astrophysics Data System (ADS)

    Ellinger, Y.; Pauzat, F.; Mousis, O.; Guilbert-Lepoutre, A.; Leblanc, F.; Ali-Dib, M.; Doronin, M.; Zicler, E.; Doressoundiram, A.

    2015-10-01

    The origin of the neutral sodium comet tail discovered in comet Hale-Bopp in 1997 is still a matter of discussion. Here we propose a scenario which is based on chemical grounds. The starting point is the chemical trapping of the Na+ ion in the refractory material during the condensation phase of the protosolar nebula, followed by its incorporation in the building blocks of the comets parent bodies. In the next step, the Na+ ions are washed out of the refractory material by the water formed by the melting of the ice due to the heat released in the radioactive decay of short period elements. When the water freezes again, the Na+ ion looses its positive charge to evolve progressively toward a neutral atom when approaching the surface of the ice. As shown by high-level numerical simulations based on first principle periodic density functional theory (DFT) to describe the solid structure of the ice, it is a neutral Na that is ejected with the sublimation of the ice top layer.

  15. Plasmalemmal and mitochondrial Na(+) -Ca(2+) exchange in neuroglia.

    PubMed

    Parpura, Vladimir; Sekler, Israel; Fern, Robert

    2016-10-01

    In the absence of the electrical signaling for which neurons are so highly specialized, GLIA rely on the slow propagation of ionic signals to mediate network events such as Ca(2+) and Na(+) waves. Glia differ from neurons in another important way, they are replete with a high density of ionic-transport proteins that are essential for them to fulfil their basic functions as guardians of the intra and extra-cellular milieux. Both the signaling and the homeostatic properties of glial cells are therefore particularly dependent upon the regulation of the two principle physiological metal cations, Ca(2+) and Na(+) . For both ions, glia express high-affinity/low capacity ATP-fuelled pumps that can rapidly move small numbers of ions against an electro-chemical gradient. For both Ca(2+) and Na(+) regulation, a single transporter family, the Na(+) -Ca(2+) exchanger (NCX), is used to maintain cellular ion homeostasis over the longer term and under conditions of prolonged or acute ionic dysregulation in astrocytes, oligodendroglia and microglia. Our understanding of glial NCX, both plasmalemmal and mitochondrial, is undergoing the kind of transformation that our understanding of glial cells, in general, has undergone in recent decades. These exchange proteins are becoming increasingly recognized for their essential roles in intracellular homeostasis while their signaling functions are starting to come to light. This review summarizes these key aspects and highlights the many areas where work has yet to begin in this rapidly evolving field. GLIA 2016;64:1646-1654. PMID:27143128

  16. Search for Na+ Pickup Ion Generated Waves at Mercury

    NASA Astrophysics Data System (ADS)

    Boardsen, S. A.; Slavin, J. A.

    2007-05-01

    Telescopic observations by Potter et al. [2002] have discovered that Mercury's Sodium exosphere has a tail extending 10's of Mercury radii. Theory predicts that the shape of and the amount of Sodium [Smyth, 1986, 1995; Ip 1986, 1990] in this exospheric tail is highly dependent upon the true anomaly of Mercury. The exospheric Na that is not reabsorbed on Mercury's surface will be photo-ionized. Computations by Ip [1986] indicated that ionized exospheric Na could significantly mass load the plasma population in Mercury's magnetosphere. These freshly created ions will be rapidly energized by the convection electric field in Mercury's magnetosphere and sheath and should be highly unstable to the generation of plasma waves. These waves could play an important role in the thermalization and retention of the Na+. Because the gyro radii of Na+ can be comparable to the scale sizes in Mercury's geospace there is an open question whether Mercury's geospace can sustain such waves. After a brief review of what was observed in the Mariner 10 magnetometer data, we will present analytic calculations of the expected pickup ion distributions, the expected unstable waves, their frequencies, wavelengths and Doppler shifts, their variation with location in Mercury's geospace and Mercury's true anomaly for both high and low solar wind convection electric fields. We will assess if and when such waves can be generated and sustained.

  17. Rechargeable Room-Temperature Na-CO2 Batteries.

    PubMed

    Hu, Xiaofei; Sun, Jianchao; Li, Zifan; Zhao, Qing; Chen, Chengcheng; Chen, Jun

    2016-05-23

    Developing rechargeable Na-CO2 batteries is significant for energy conversion and utilization of CO2 . However, the reported batteries in pure CO2 atmosphere are non-rechargeable with limited discharge capacity of 200 mAh g(-1) . Herein, we realized the rechargeability of a Na-CO2 battery, with the proposed and demonstrated reversible reaction of 3 CO2 +4 Na↔2 Na2 CO3 +C. The battery consists of a Na anode, an ether-based electrolyte, and a designed cathode with electrolyte-treated multi-wall carbon nanotubes, and shows reversible capacity of 60000 mAh g(-1) at 1 A g(-1) (≈1000 Wh kg(-1) ) and runs for 200 cycles with controlled capacity of 2000 mAh g(-1) at charge voltage <3.7 V. The porous structure, high electro-conductivity, and good wettability of electrolyte to cathode lead to reduced electrochemical polarization of the battery and further result in high performance. Our work provides an alternative approach towards clean recycling and utilization of CO2 . PMID:27089434

  18. Plasmalemmal and mitochondrial Na(+) -Ca(2+) exchange in neuroglia.

    PubMed

    Parpura, Vladimir; Sekler, Israel; Fern, Robert

    2016-10-01

    In the absence of the electrical signaling for which neurons are so highly specialized, GLIA rely on the slow propagation of ionic signals to mediate network events such as Ca(2+) and Na(+) waves. Glia differ from neurons in another important way, they are replete with a high density of ionic-transport proteins that are essential for them to fulfil their basic functions as guardians of the intra and extra-cellular milieux. Both the signaling and the homeostatic properties of glial cells are therefore particularly dependent upon the regulation of the two principle physiological metal cations, Ca(2+) and Na(+) . For both ions, glia express high-affinity/low capacity ATP-fuelled pumps that can rapidly move small numbers of ions against an electro-chemical gradient. For both Ca(2+) and Na(+) regulation, a single transporter family, the Na(+) -Ca(2+) exchanger (NCX), is used to maintain cellular ion homeostasis over the longer term and under conditions of prolonged or acute ionic dysregulation in astrocytes, oligodendroglia and microglia. Our understanding of glial NCX, both plasmalemmal and mitochondrial, is undergoing the kind of transformation that our understanding of glial cells, in general, has undergone in recent decades. These exchange proteins are becoming increasingly recognized for their essential roles in intracellular homeostasis while their signaling functions are starting to come to light. This review summarizes these key aspects and highlights the many areas where work has yet to begin in this rapidly evolving field. GLIA 2016;64:1646-1654.

  19. Results from NA60 experiment at the CERN SPS

    SciTech Connect

    Usai, G.; Cicalo, C.; De Falco, A.; Floris, M.; Masoni, A.; Puddu, G.; Serci, S.; Arnaldi, R.; Colla, A.; Cortese, P.; Ferretti, A.; Oppedisano, C.; Averbeck, R.; Drees, A.; Banicz, K.; Castor, J.; Devaux, A.; Force, P.; Manso, F.; Chaurand, B.

    2006-07-11

    The NA60 experiment studies open charm and prompt dimuon production in proton-nucleus and nucleus-nucleus collisions at the CERN SPS. During 2003 the experiment collected data in Indium-Indium collisions at 158 GeV per nucleon. In this paper the first results on low mass dimuons, intermediate mass dimuons and J/{psi} suppression are presented.

  20. Reductive amination of carbohydrates using NaBH(OAc)3.

    PubMed

    Dalpathado, Dilusha S; Jiang, Hui; Kater, Marcus A; Desaire, Heather

    2005-03-01

    An improved protocol for reductive amination of carbohydrates is developed. This derivatization facilitates the detection of oligosaccharides in HPLC-UV and mass spectrometric applications by enhancing the signal of the carbohydrates. In this study, reductive amination was achieved using NaBH(OAc)3. This reducing agent is an attractive alternative to the toxic, but extensively used reducing agent, NaBH3CN. Several types of carbohydrates were successfully derivatized using NaBH(OAc)3, and the results obtained from this protocol were compared with those obtained with NaBH(OAc)3. Both reducing agents were equally effective in side-by-side analysis. Two purification strategies (purification by zip-tip and HPLC) were implemented and the instrumental limit of detection of each method was compared. The detection limit was approximately 1,000 times lower when the purification was done using HPLC, compared to using the zip-tip. Since the derivatization by-products in this protocol are not toxic, MS analysis also could also be performed directly, without purification. The MS/MS data of derivatized and underivatized oligosaccharides were acquired as well. The derivatized oligosaccharides produce more easily interpretable product ions than underivatized oligosaccharides.

  1. Multimodal action of single Na+ channels in myocardial mouse cells.

    PubMed

    Böhle, T; Benndorf, K

    1995-01-01

    Unitary Na+ currents of myocardial mouse cells were studied at room temperature in 10 cell-attached patches, each containing one and only one channel. Small-pore patch pipettes (resistance 10-97 M omega when filled with 200% Tyrode's solution) with exceptionally thick walls were used. Observed were both rapidly inactivating (6 patches) and slowly inactivating (3 patches) Na+ currents. In one patch, a slow transition from rather fast to slow inactivation was detected over a time of 0.5 h. A short and a long component of the open-channel life time were recorded at the beginning, but only a short one at the end of the experiment. Concomitantly, the first latency was slowed. Amplitude histograms showed that the electrochemical driving force across the pore of the channel did not change during this time. In three patches, a fast and repetitive switching between different modes of Na+ channel action could be clearly identified by plotting the long-time course of the averaged current per trace. The ensemble-averaged current formed in each mode was different in kinetics and amplitude. Each mode had a characteristic mean open-channel life time and distribution of first latency, but the predominant single-channel current amplitude was unaffected by mode switches. It is concluded that two types of changes in kinetics may happen in a single Na+ channel: fast and reversible switches between different modes, and a slow loss of inactivation.

  2. Project ELaNa and NASA's CubeSat Initiative

    NASA Technical Reports Server (NTRS)

    Skrobot, Garrett Lee

    2010-01-01

    This slide presentation reviews the NASA program to use expendable lift vehicles (ELVs) to launch nanosatellites for the purpose of enhancing educational research. The Education Launch of Nanosatellite (ELaNa) project, run out of the Launch Services Program is requesting proposals for CubeSat type payload to provide information that will aid or verify NASA Projects designs while providing higher educational research

  3. Luminescence and radiation resistance of undoped NaI crystals

    SciTech Connect

    Shiran, N. Boiaryntseva, I.; Gektin, A.; Gridin, S.; Shlyakhturov, V.; Vasuykov, S.

    2014-11-15

    Highlights: • The performance of NaI scintillators depends on luminescence properties. • A criterion of crystals’ purity level is radiation colorability at room temperature. • The traces of the most dangerous impurities were detected. • Crucial role in efficiency of pure NaI scintillator play the crystal perfection. - Abstract: Undoped NaI single crystal is an excellent scintillator at low temperature. However, scintillation parameters of different quality crystals vary in a wide range, significantly exceeding measurement error. Experimental data demonstrate the features of luminescence, radiation induced coloration, and afterglow dependence on the quality of nominally pure crystals. It is found that defects level that allows to elucidate artefacts introduced by traces of harmful impurities corresponds to 3 × 10{sup 15} cm{sup −3} that significantly overhead accuracy of chemical and absorption analysis. It is shown that special raw material treatment before and during the single crystal growth allows to reach NaI purity level that avoids impurities influence to the basic luminescence data.

  4. Altered erythrocyte Na-K pump in anorectic patients

    SciTech Connect

    Pasquali, R.; Strocchi, E.; Malini, P.; Casimirri, F.; Ambrosioni, E.; Melchionda, N.; Labo, G.

    1985-07-01

    The status of the erythrocyte sodium pump was evaluated in a group of patients suffering from anorexia nervosa and a group of healthy female control subjects. Anorectic patients showed significantly higher mean values of digoxin-binding sites/cell (ie, the number of Na-K-ATPase units) with respect to control subjects while no differences were found in the specific /sup 86/Rb uptake (which reflects the Na-K-ATPase activity) between the two groups. A significant correlation was found between relative weight and the number of Na-K-ATPase pump units (r = -0.66; P less than 0.0001). Anorectic patients showed lower serum T3 concentrations (71.3 +/- 53 ng/dL) with respect to control subjects (100.8 +/- 4.7 ng/dL; P less than 0.0005) and a significant negative correlation between T3 levels and the number of pump units (r = -0.52; P less than 0.003) was found. This study therefore shows that the erythrocyte Na-K pump may be altered in several anorectic patients. The authors suggest that this feature could be interrelated with the degree of underweight and/or malnutrition.

  5. Na+ Transport in Cardiac Myocytes; Implications for Excitation-Contraction Coupling

    PubMed Central

    Bers, Donald M.; Despa, Sanda

    2009-01-01

    Intracellular Na+ concentration ([Na+]i) is very important in modulating the contractile and electrical activity of the heart. Upon electrical excitation of the myocardium, voltage-dependent Na+ channels open, triggering the upstroke of the action potential (AP). During the AP, Ca2+ enters the myocytes via L-type Ca2+ channels. This triggers Ca2+ release from the sarcoplasmic reticulum (SR) and thus activates contraction. Relaxation occurs when cytosolic Ca2+ declines, mainly due to re-uptake into the SR via SR Ca2+-ATPase and extrusion from the cell via the Na+/Ca2+ exchanger (NCX). NCX extrudes one Ca2+ ion in exchange for three Na+ ions and its activity is critically regulated by [Na+]i. Thus, via NCX, [Na+]i is centrally involved in the regulation of intracellular [Ca2+] and contractility. Na+ brought in by Na+ channels, NCX and other Na+ entry pathways is extruded by the Na+/K+ pump (NKA) to keep [Na+]i low. NKA is regulated by phospholemman, a small sarcolemmal protein that associates with NKA. Unphosphorylated phospholemman inhibits NKA by decreasing the pump affinity for internal Na+ and this inhibition is relieved upon phosphorylation. Here we discuss the main characteristics of the Na+ transport pathways in cardiac myocytes and their physiological and pathophysiological relevance. PMID:19243007

  6. Multiple quantum filtered (23)Na NMR in the Langendorff perfused mouse heart: Ratio of triple/double quantum filtered signals correlates with [Na]i.

    PubMed

    Eykyn, Thomas R; Aksentijević, Dunja; Aughton, Karen L; Southworth, Richard; Fuller, William; Shattock, Michael J

    2015-09-01

    We investigate the potential of multiple quantum filtered (MQF) (23)Na NMR to probe intracellular [Na]i in the Langendorff perfused mouse heart. In the presence of Tm(DOTP) shift reagent the triple quantum filtered (TQF) signal originated largely from the intracellular sodium pool with a 32±6% contribution of the total TQF signal arising from extracellular sodium, whilst the rank 2 double-quantum filtered signal (DQF), acquired with a 54.7° flip-angle pulse, originated exclusively from the extracellular sodium pool. Given the different cellular origins of the (23)Na MQF signals we propose that the TQF/DQF ratio can be used as a semi-quantitative measure of [Na]i in the mouse heart. We demonstrate a good correlation of this ratio with [Na]i measured with shift reagent at baseline and under conditions of elevated [Na]i. We compare the measurements of [Na]i using both shift reagent and TQF/DQF ratio in a cohort of wild type mouse hearts and in a transgenic PLM(3SA) mouse expressing a non-phosphorylatable form of phospholemman, showing a modest but measurable elevation of baseline [Na]i. MQF filtered (23)Na NMR is a potentially useful tool for studying normal and pathophysiological changes in [Na]i, particularly in transgenic mouse models with altered Na regulation.

  7. Multiple quantum filtered 23Na NMR in the Langendorff perfused mouse heart: Ratio of triple/double quantum filtered signals correlates with [Na]i

    PubMed Central

    Eykyn, Thomas R.; Aksentijević, Dunja; Aughton, Karen L.; Southworth, Richard; Fuller, William; Shattock, Michael J.

    2015-01-01

    We investigate the potential of multiple quantum filtered (MQF) 23Na NMR to probe intracellular [Na]i in the Langendorff perfused mouse heart. In the presence of Tm(DOTP) shift reagent the triple quantum filtered (TQF) signal originated largely from the intracellular sodium pool with a 32 ± 6% contribution of the total TQF signal arising from extracellular sodium, whilst the rank 2 double-quantum filtered signal (DQF), acquired with a 54.7° flip-angle pulse, originated exclusively from the extracellular sodium pool. Given the different cellular origins of the 23Na MQF signals we propose that the TQF/DQF ratio can be used as a semi-quantitative measure of [Na]i in the mouse heart. We demonstrate a good correlation of this ratio with [Na]i measured with shift reagent at baseline and under conditions of elevated [Na]i. We compare the measurements of [Na]i using both shift reagent and TQF/DQF ratio in a cohort of wild type mouse hearts and in a transgenic PLM3SA mouse expressing a non-phosphorylatable form of phospholemman, showing a modest but measurable elevation of baseline [Na]i. MQF filtered 23Na NMR is a potentially useful tool for studying normal and pathophysiological changes in [Na]i, particularly in transgenic mouse models with altered Na regulation. PMID:26196304

  8. Effects of Na2MoO4 and Na2WO4 on molybdenum and tungsten electrodes for the alkali metal thermoelectric converter (AMTEC)

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Wheeler, B. L.; Jeffries-Nakamura, B.; Loveland, M. E.; Bankston, C. P.

    1988-01-01

    The effects of adding Na2MoO4 and Na2WO4 to porous Mo and W electrodes, respectively, on the performance and impedance characteristics of the electrodes in an alkali metal thermoelectric converter (AMTEC) were investigated. It was found that corrosion of the porous electrode by Na2MoO4 or Na2WO4 to form Na2MO3O6 and WO2, respectively, and recrystallization of the Mo or W as the salt evaporates, result in major morphological changes including a loss of columnar structure and a significant increase in porosity. This effect is more pronounced in Na2MoO4/Mo electrodes, due to the lower stability of Na2MoO4.

  9. The Na+ transport in gram-positive bacteria defect in the Mrp antiporter complex measured with 23Na nuclear magnetic resonance.

    PubMed

    Górecki, Kamil; Hägerhäll, Cecilia; Drakenberg, Torbjörn

    2014-01-15

    (23)Na nuclear magnetic resonance (NMR) has previously been used to monitor Na(+) translocation across membranes in gram-negative bacteria and in various other organelles and liposomes using a membrane-impermeable shift reagent to resolve the signals resulting from internal and external Na(+). In this work, the (23)Na NMR method was adapted for measurements of internal Na(+) concentration in the gram-positive bacterium Bacillus subtilis, with the aim of assessing the Na(+) translocation activity of the Mrp (multiple resistance and pH) antiporter complex, a member of the cation proton antiporter-3 (CPA-3) family. The sodium-sensitive growth phenotype observed in a B. subtilis strain with the gene encoding MrpA deleted could indeed be correlated to the inability of this strain to maintain a lower internal Na(+) concentration than an external one. PMID:24139955

  10. Charge order and anomalous magnetism in the Na cobaltates

    NASA Astrophysics Data System (ADS)

    Alloul, Henri

    2008-03-01

    The layered Na cobaltates have some analogies with the cuprates as 2D conductivity occurs in the CoO2 planes and doping can be modified by changing the Na content. Also ordered magnetic phases have been evidenced, but unexpectedly for large values of x for which one would expect a hole doping of the band insulator NaCoO2. Indeed, in the high crystal field on the Co sites in these compounds, an ionic picture for the Co states would correspond to low spin configurations Co^3+, S=0 or Co^4+, S=1/2. We shall present SQUID and ^23Na and ^59Co NMR data [1] taken on samples synthetized and characterized by X ray cristallography in LLB, Saclay. We evidence that the Co charge is uniform for x=0.35 as in the hydrated superconducting phase. For high Na contents the samples are found to display ordered Na structures or mixtures of those, with different x values. In pure phases isolated for specific x values, we evidence a charge disproportionation into non magnetic Co^3+ and more magnetic Co sites with an average charge of about Co^3.5+, except for x=0.5 [2]. This hole delocalization and charge order occur both for paramagnetic and AF phases [3]. NMR investigations of the dynamic susceptibilities allow us to characterize the nature of the in plane electronic correlations in most parts of the phase diagram. Contrary to the case of most cuprates for which dopant disorder is quite influential, the hole doping achieved in cobaltate samples is associated with the insertion of well ordered Na planar structures. They have to be taken into account to explain theoretically the metallicity, the magnetic properties and their evolution with doping. [1] I. Mukhamedchine, H. Alloul, G. Collin et N. Blanchard, Phys. Rev. Letters, 94, 247602 (2005). [2] http://arxiv.org/find/cond-mat/1/au:+BobroffJ/0/1/0/all/0/1, J. Bobroff; http://arxiv.org/find/cond-mat/1/au:+LangG/0/1/0/all/0/1, G. Lang; http://arxiv.org/find/cond-mat/1/au:+AlloulH/0/1/0/all/0/1, H. Alloul; http://arxiv.org/find/cond-mat/1

  11. K+ and Na+ absorption by outer sulcus epithelial cells.

    PubMed

    Marcus, D C; Chiba, T

    1999-08-01

    Transduction of sound into nerve impulses by hair cells depends on modulation of a current carried primarily by K+ into the cell across apical transduction channels that are permeable to cations. The cochlear function thus depends on active secretion of K+ accompanied by absorption of Na+ by epithelial cells enclosing the cochlear duct. The para-sensory cells which participate in the absorption of Na+ (down to the uniquely low level of 1 mM) were previously unidentified and the existence of a para-sensory pathway which actively absorbs K+ was previously unknown. A relative short circuit current (Isc,probe, measured as the extracellular current density with a vibrating electrode) was directed into the apical side of the outer sulcus epithelium, decreased by ouabain (1 mM), an inhibitor of Na+, K(+)-ATPase, and found to depend on bath Na+ and K+ but on neither Ca2+ nor Cl-. Isc,probe was shown to be an active current by its sensitivity to ouabain. On-cell patch clamp recordings of the apical membrane of outer sulcus cells displayed a channel activity, which carried inward currents under conditions identical to those used to measure Isc,probe. Both Isc,probe and non-selective cation channels (27.4+/-0.6 ps, n = 22) in excised outside-out patches from the apical membrane were inhibited by Gd3+ (1 mM). Ics,prob was also inhibited by 5 mM lidocaine, 1 mM quinine and 500 microM amiloride but not by 10 microM amiloride. These results demonstrate that outer sulcus epithelial cells contribute to the homeostasis of endolymph by actively absorbing Na+ and K+. An entry pathway in the apical membrane was shown to be through non-selective cation channels that were sensitive to Gd3+.

  12. Na+-independent phosphate transport in Caco2BBE cells

    PubMed Central

    Candeal, Eduardo; Caldas, Yupanqui A.; Guillén, Natalia; Levi, Moshe

    2014-01-01

    Pi transport in epithelia has both Na+-dependent and Na+-independent components, but so far only Na+-dependent transporters have been characterized in detail and molecularly identified. Consequently, in the present study, we initiated the characterization and analysis of intestinal Na+-independent Pi transport using an in vitro model, Caco2BBE cells. Only Na+-independent Pi uptake was observed in these cells, and Pi uptake was dramatically increased when cells were incubated in high-Pi DMEM (4 mM) from 1 day to several days. No response to low-Pi medium was observed. The increased Pi transport was mainly caused by Vmax changes, and it was prevented by actinomycin D and cycloheximide. Pi transport in cells grown in 1 mM Pi (basal DMEM) decreased at pH > 7.5, and it was inhibited with proton ionophores. Pi transport in cells incubated with 4 mM Pi increased with alkaline pH, suggesting a preference for divalent phosphate. Pi uptake in cells in 1 mM Pi was completely inhibited only by Pi and partially inhibited by phosphonoformate, oxalate, DIDS, SITS, SO42−, HCO3−, and arsenate. This inhibition pattern suggests that more than one Pi transporter is active in cells maintained with 1 mM Pi. Phosphate transport from cells maintained at 4 mM Pi was only partially inhibited by phosphonoformate, oxalate, and arsenate. Attempts to identify the responsible transporters showed that multifunctional anion exchangers of the Slc26 family as well as members of Slc17, Slc20, and Slc37 and the Pi exporter xenotropic and polytropic retrovirus receptor 1 are not involved. PMID:25298422

  13. Na+-independent phosphate transport in Caco2BBE cells.

    PubMed

    Candeal, Eduardo; Caldas, Yupanqui A; Guillén, Natalia; Levi, Moshe; Sorribas, Víctor

    2014-12-15

    Pi transport in epithelia has both Na(+)-dependent and Na(+)-independent components, but so far only Na(+)-dependent transporters have been characterized in detail and molecularly identified. Consequently, in the present study, we initiated the characterization and analysis of intestinal Na(+)-independent Pi transport using an in vitro model, Caco2BBE cells. Only Na(+)-independent Pi uptake was observed in these cells, and Pi uptake was dramatically increased when cells were incubated in high-Pi DMEM (4 mM) from 1 day to several days. No response to low-Pi medium was observed. The increased Pi transport was mainly caused by Vmax changes, and it was prevented by actinomycin D and cycloheximide. Pi transport in cells grown in 1 mM Pi (basal DMEM) decreased at pH > 7.5, and it was inhibited with proton ionophores. Pi transport in cells incubated with 4 mM Pi increased with alkaline pH, suggesting a preference for divalent phosphate. Pi uptake in cells in 1 mM Pi was completely inhibited only by Pi and partially inhibited by phosphonoformate, oxalate, DIDS, SITS, SO4 (2-), HCO3 (-), and arsenate. This inhibition pattern suggests that more than one Pi transporter is active in cells maintained with 1 mM Pi. Phosphate transport from cells maintained at 4 mM Pi was only partially inhibited by phosphonoformate, oxalate, and arsenate. Attempts to identify the responsible transporters showed that multifunctional anion exchangers of the Slc26 family as well as members of Slc17, Slc20, and Slc37 and the Pi exporter xenotropic and polytropic retrovirus receptor 1 are not involved.

  14. Semi-volatiles at Mercury: Sodium (Na) and potassium (K)

    NASA Technical Reports Server (NTRS)

    Sprague, A.

    1994-01-01

    Several lines of evidence now suggest that Mercury is a planet rich in moderately-volatile elements such as Na and K. Recent mid-infrared spectral observations of Mercury's equatorial and mid-latitude region near 120 degrees mercurian longitude indicate the presence of plagioclase feldspar. Spectra of Mercury's surface exhibit spectral activity similar to labradorite (plagioclase feldspar with NaAlSi3O8: 30-50 percent) and bytownite (NaAlSi3O8: 10-30 percent). These surface studies were stimulated by the relatively large abundance of Na and K observed in Mercury's atmosphere. An enhanced column of K is observed at the longitudes of Caloris Basin and of the antipodal terrain. Extreme heating at these 'hot' longitudes and severe fracturing suffered from the large impact event could lead to enhanced outgassing from surface or subsurface materials. Alternatively, sputtering from a surface enriched in K could be the source of the observed enhancement. Recent microwave measurements of Mercury also give indirect evidence of a mercurian regolith less FeO-rich than the Moon. An anomalously high index of refraction derived from the whole-disk integrated phase curve of Danjon may also be indicative of surface sulfides contributing to a regolith that is moderately volatile-rich. The recent exciting observations of radar-bright spots at high latitudes also indicate that a substance of high volume scattering, like ice, is present in shadowed regions. Other radar-bright spots have been seen at locations of Na enhancements on the atmosphere. All combined, these pieces of evidence point to a planet that is not severely depleted in volatiles or semi-volatiles.

  15. Indirect activation of the epithelial Na+ channel by trypsin.

    PubMed

    Bengrine, Abderrahmane; Li, Jinqing; Hamm, L Lee; Awayda, Mouhamed S

    2007-09-14

    We tested the hypothesis that the serine protease trypsin can indirectly activate the epithelial Na(+) channel (ENaC). Experiments were carried out in Xenopus oocytes and examined the effects on the channel formed by all three human ENaC subunits and that formed by Xenopus epsilon and human beta and gamma subunits (epsilonbetagammaENaC). Low levels of trypsin (1-10 ng/ml) were without effects on the oocyte endogenous conductances and were specifically used to test the effects on ENaC. Addition of 1 ng/ml trypsin for 60 min stimulated the amiloride-sensitive human ENaC conductance (g(Na)) by approximately 6-fold. This effect on the g(Na) was [Na(+)]-independent, thereby ruling out an interaction with channel feedback inhibition by Na(+). The indirect nature of this activation was confirmed in cell-attached patch clamp experiments with trypsin added to the outside of the pipette. Trypsin was comparatively ineffective at activating epsilonbetagammaENaC, a channel that exhibited a high spontaneous open probability. These observations, in combination with surface binding experiments, indicated that trypsin indirectly activated membrane-resident channels. Activation by trypsin was also dependent on catalytic activity of this protease but was not accompanied by channel subunit proteolysis. Channel activation was dependent on downstream activation of G-proteins and was blocked by G-protein inhibition by injection of guanyl-5'-yl thiophosphate and by pre-stimulation of phospholipase C. These data indicate a receptor-mediated activation of ENaC by trypsin. This trypsin-activated receptor is distinct from that of protease-activated receptor-2, because the response to trypsin was unaffected by protease-activated receptor-2 overexpression or knockdown. PMID:17627947

  16. Preparation and visible light induced photocatalytic activity of C-NaTaO3 and C-NaTaO3-Cl-TiO2 composite.

    PubMed

    Wu, Xiaoyong; Yin, Shu; Dong, Qiang; Sato, Tsugio

    2013-12-21

    A nice visible light responsive C-doped NaTaO3 (C-NaTaO3) particle has been successfully prepared by a facile solvothermal method using water-ethylene glycol mixed solutions as solvent. The results presented that the carbon could be easily incorporated in NaTaO3 from ethylene glycol during a solvothermal reaction, finally leading to excellent visible light absorption. The as-synthesized C-NaTaO3 showed excellent visible light induced photocatalytic activity superior to those of pure NaTaO3 and commercial P25. In addition, in order to further improve the visible light driven photocatalytic performance of C-NaTaO3, a new C-doped NaTaO3-Cl-doped TiO2 (C-NaTaO3-Cl-TiO2) core-shell type of composite was also fabricated. After coupling C-NaTaO3 with Cl-TiO2, the visible light induced NOx gas destruction ability of C-NaTaO3-Cl-TiO2 composite was significantly enhanced as compared to those of sole C-NaTaO3 and Cl-TiO2, probably due to the hindrance of the recombination rate of photogenerated electron-hole pairs. The C-NaTaO3 particle and C-NaTaO3-Cl-TiO2 composite prepared in this work would probably provide a new way to prepare high performance of visible light induced perovskite-type NaTaO3 based photocatalysts.

  17. Effects of Ouabain on Proliferation of Human Endothelial Cells Correlate with Na+,K+-ATPase Activity and Intracellular Ratio of Na+ and K.

    PubMed

    Tverskoi, A M; Sidorenko, S V; Klimanova, E A; Akimova, O A; Smolyaninova, L V; Lopina, O D; Orlov, S N

    2016-08-01

    Side-by-side with inhibition of the Na+,K+-ATPase ouabain and other cardiotonic steroids (CTS) can affect cell functions by mechanisms other than regulation of the intracellular Na+ and K+ ratio ([Na+]i/[K+]i). Thus, we compared the dose- and time-dependences of the effect of ouabain on intracellular [Na+]i/[K+]i ratio, Na+,K+-ATPase activity, and proliferation of human umbilical vein endothelial cells (HUVEC). Treatment of the cells with 1-3 nM ouabain for 24-72 h decreased the [Na+]i/[K+]i ratio and increased cell proliferation by 20-50%. We discovered that the same ouabain concentrations increased Na+,K+-ATPase activity by 25-30%, as measured by the rate of (86)Rb(+) influx. Higher ouabain concentrations inhibited Na+,K+-ATPase, increased [Na+]i/[K+]i ratio, suppressed cell growth, and caused cell death. When cells were treated with low ouabain concentrations for 48 or 72 h, a negative correlation between [Na+]i/[K+]i ratio and cell growth activation was observed. In cells treated with high ouabain concentrations for 24 h, the [Na+]i/[K+]i ratio correlated positively with proliferation inhibition. These data demonstrate that inhibition of HUVEC proliferation at high CTS concentrations correlates with dissipation of the Na+ and K+ concentration gradients, whereas cell growth stimulation by low CTS doses results from activation of Na+,K+-ATPase and decrease in the [Na+]i/[K+]i ratio. PMID:27677555

  18. Light-driven Na(+) pump from Gillisia limnaea: a high-affinity Na(+) binding site is formed transiently in the photocycle.

    PubMed

    Balashov, Sergei P; Imasheva, Eleonora S; Dioumaev, Andrei K; Wang, Jennifer M; Jung, Kwang-Hwan; Lanyi, Janos K

    2014-12-01

    A group of microbial retinal proteins most closely related to the proton pump xanthorhodopsin has a novel sequence motif and a novel function. Instead of, or in addition to, proton transport, they perform light-driven sodium ion transport, as reported for one representative of this group (KR2) from Krokinobacter. In this paper, we examine a similar protein, GLR from Gillisia limnaea, expressed in Escherichia coli, which shares some properties with KR2 but transports only Na(+). The absorption spectrum of GLR is insensitive to Na(+) at concentrations of ≤3 M. However, very low concentrations of Na(+) cause profound differences in the decay and rise time of photocycle intermediates, consistent with a switch from a "Na(+)-independent" to a "Na(+)-dependent" photocycle (or photocycle branch) at ∼60 μM Na(+). The rates of photocycle steps in the latter, but not the former, are linearly dependent on Na(+) concentration. This suggests that a high-affinity Na(+) binding site is created transiently after photoexcitation, and entry of Na(+) from the bulk to this site redirects the course of events in the remainder of the cycle. A greater concentration of Na(+) is needed for switching the reaction path at lower pH. The data suggest therefore competition between H(+) and Na(+) to determine the two alternative pathways. The idea that a Na(+) binding site can be created at the Schiff base counterion is supported by the finding that upon perturbation of this region in the D251E mutant, Na(+) binds without photoexcitation. Binding of Na(+) to the mutant shifts the chromophore maximum to the red like that of H(+), which occurs in the photocycle of the wild type.

  19. Apical membrane Na+/H+ exchange in Necturus gallbladder epithelium. Its dependence on extracellular and intracellular pH and on external Na+ concentration

    PubMed Central

    1990-01-01

    Intracellular microelectrode techniques and extracellular pH measurements were used to study the dependence of apical Na+/H+ exchange on mucosal and intracellular pH and on mucosal solution Na+ concentration ([Na+]o). When mucosal solution pH (pHo) was decreased in gallbladders bathed in Na(+)-containing solutions, aNai fell. The effect of pHo is consistent with titration of a single site with an apparent pK of 6.29. In Na(+)-depleted tissues, increasing [Na+]o from 0 to values ranging from 2.5 to 110 mM increased aNai; the relationship was well described by Michaelis-Menten kinetics. The apparent Km was 15 mM at pHo 7.5 and increased to 134 mM at pHo 6.5, without change in Vmax. In Na(+)-depleted gallbladders, elevating [Na+]o from 0 to 25 mM increased aNai and pHi and caused acidification of a poorly buffered mucosal solution upon stopping the superfusion; lowering pHo inhibited both apical Na+ entry and mucosal solution acidification. Both effects can be ascribed to titration of a single site; the apparent pK's were 7.2 and 7.4, respectively. Diethylpyrocarbonate (DEPC), a histidine- specific reagent, reduced mucosal acidification by 58 +/- 4 or 39 +/- 6% when exposure to the drug was at pHo 7.5 or 6.5, respectively. Amiloride (1 mM) did not protect against the DEPC inhibition, but reduced both apical Na+ entry and mucosal acidification by 63 +/- 5 and 65 +/- 9%, respectively. In the Na(+)-depleted tissues mean pHi was 6.7. Cells were alkalinized by exposure to mucosal solutions containing high concentrations of nicotine or methylamine. Estimates of apical Na+ entry at varying pHi, upon increasing [Na+]o from 0 to 25 mM, indicate that Na+/H+ exchange is active at pHi 7.4. Intracellular H+ stimulated apical Na+ entry by titration of more than one site (apparent pK 7.1, Hill coefficient 1.7). The results suggest that external Na+ and H+ interact with one site of the Na+/H+ exchanger and that cytoplasmic H+ acts on at least two sites. The external titratable group

  20. Interfacial electronic structure of Na deposited on rubrene thin film studied by synchrotron radiation photoemission

    NASA Astrophysics Data System (ADS)

    Wei, Ching-Hsuan; Cheng, Chiu-Ping; Lin, Hong-Cheu; Pi, Tun-Wen

    2015-12-01

    The electronic structure of rubrene doped with various concentrations of Na was studied by synchrotron-radiation photoemission. Three stages of development were found with increasing Na concentration; Na penetrating deep into the organic film, followed by development of gap states, and ended with a metallic Na film. The charge transfer from Na to rubrene resulted in a vacuum-level shift. By doping Na into rubrene, we could control the IP of the organic molecule, which is favorable for application in organic semiconductor devices.

  1. Na sup + pump in renal tubular cells is regulated by endogenous Na sup + -K sup + -ATPase inhibitor from hypothalamus

    SciTech Connect

    Cantiello, H.F.; Chen, E.; Ray, S.; Haupert, G.T. Jr. )

    1988-10-01

    Bovine hypothalamus contains a high affinity, specific, reversible inhibitor of mammalian Na{sup +}-K{sup +}-ATPase. Kinetic analysis using isolated membrane fractions showed binding and dissociation rates of the hypothalamic factor (HF) to be (like ouabain) relatively long (off rate = 60 min). To determine whether the kinetics of inhibition in intact cells might be more consistent with regulation of physiological processes in vivo, binding and dissociation reactions of HF in intact renal epithelial cells (LLC-PK{sup 1}) were studied using {sup 86}Rb{sup +} uptake and ({sup 3}H)ouabain binding. As with membranes, a 60-min incubation with HF inhibited Na{sup +}-K{sup +}-ATPase in LLC-PK{sub 1} cells. In contrast to membrane studies, no prolonged incubation with LLC-PK{sub 1} was needed to observe inhibition of Na{sup +}-K{sup +}-ATPase. HF caused a 33% inhibition of ouabain-sensitive {sup 86}Rb{sup +} influx within 10 min. Incubation of cells with HF followed by washout showed rapid reversal of pump inhibition and a doubling of pump activity. The dose-response curve for HF inhibition of LLC-PK{sub 1} {sup 86}Rb{sup +} uptake showed a sigmoidal shape consistent with an allosteric binding reaction. Thus HF is a potent regulator of Na{sup +}-K{sup +}-ATPase activity in intact renal cells, with binding and dissociation reactions consistent with relevant physiological processes.

  2. Genetic Variation of the Alpha Subunit of the Epithelial Na+ Channels Influences Exhaled Na+ in Healthy Humans

    PubMed Central

    Foxx-Lupo, William T.; Wheatley, Courtney M.; Baker, Sarah E.; Cassuto, Nicholas A.; Delamere, Nicholas A.; Snyder, Eric M.

    2011-01-01

    Epithelial Na+ Channels (ENaC) are located on alveolar cells and are important in β2-adrenergic receptor-mediated lung fluid clearance through the removal of Na+ from the alveolar airspace. Previous work has demonstrated that genetic variation of the alpha subunit of ENaC at amino acid 663 is important in channel function: cells with the genotype resulting in alanine at amino acid 663 (A663) demonstrate attenuated function when compared to genotypes with at least one allele encoding threonine (T663, AT/TT). We sought to determine the influence of genetic variation at position 663 of ENaC on exhaled Na+ in healthy humans. Exhaled Na+ was measured in 18 AA and 13 AT/TT subjects (age=27±8 vs. 30±10yrs., ht.=174±12 vs. 171±10cm., wt=68±12 vs. 73±14kg., BMI=22±3 vs. 25±4kg/m2, mean±SD, for AA and AT/TT, respectively). Measurements were made at baseline and at 30, 60 and 90 minutes following the administration of a nebulized β2-agonist (albuterol sulfate, 2.5mg diluted in 3ml normal saline). The AA group had a higher baseline level of exhaled Na+ and a greater response to β2-agonist stimulation (baseline= 3.1±1.8 vs. 2.3±1.5mmol/l; 30min-post= 2.1±0.7 vs. 2.2±0.8mmol/l; 60min-post= 2.0±0.5 vs. 2.3±1.0mmol/l; 90min-post= 1.8±0.8 vs. 2.6±1.5mmol/l, mean±SD, for AA and AT/TT, respectively, p<0.05). The results are consistent with the notion that genetic variation of ENaC influences β2-adrenergic receptor stimulated Na+ clearance in the lungs, as there was a significant reduction in exhaled Na+ over time in the AA group. PMID:21889619

  3. Cytoplasmic Na+-dependent modulation of mitochondrial Ca2+ via electrogenic mitochondrial Na+–Ca2+ exchange

    PubMed Central

    Kim, Bongju; Matsuoka, Satoshi

    2008-01-01

    To clarify the role of mitochondrial Na+–Ca2+ exchange (NCXmito) in regulating mitochondrial Ca2+ (Ca2+mito) concentration at intact and depolarized mitochondrial membrane potential (ΔΨmito), we measured Ca2+mito and ΔΨmito using fluorescence probes Rhod-2 and TMRE, respectively, in the permeabilized rat ventricular cells. Applying 300 nm cytoplasmic Ca2+ (Ca2+c) increased Ca2+mito and this increase was attenuated by cytoplasmic Na+ (Na+c) with an IC50 of 2.4 mm. To the contrary, when ΔΨmito was depolarized by FCCP, a mitochondrial uncoupler, Na+c enhanced the Ca2+c-induced increase in Ca2+mito with an EC50 of about 4 mm. This increase was not significantly affected by ruthenium red or cyclosporin A. The inhibition of NCXmito by CGP-37157 further increased Ca2+mito when ΔΨmito was intact, while it suppressed the Ca2+mito increase when ΔΨmito was depolarized, suggesting that ΔΨmito depolarization changed the exchange mode from forward to reverse. Furthermore, ΔΨmito depolarization significantly reduced the Ca2+mito decrease via forward mode, and augmented the Ca2+mito increase via reverse mode. When the respiratory chain was attenuated, the induction of the reverse mode of NCXmito hyperpolarized ΔΨmito, while ΔΨmito depolarized upon inducing the forward mode of NCXmito. Both changes in ΔΨmito were remarkably inhibited by CGP-37157. The above experimental data indicated that NCXmito is voltage dependent and electrogenic. This notion was supported theoretically by computer simulation studies with an NCXmito model constructed based on present and previous studies, presuming a consecutive and electrogenic Na+–Ca2+ exchange and a depolarization-induced increase in Na+ flux. It is concluded that Ca2+mito concentration is dynamically modulated by Na+c and ΔΨmito via electrogenic NCXmito. PMID:18218682

  4. INTEX-NA: Intercontinental Chemical Transport Experiment - North America

    NASA Technical Reports Server (NTRS)

    Singh, Hanwant B.; Jacob, D.; Pfister, L.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    INTEX-NA is an integrated atmospheric chemistry field experiment to be performed over North America using the NASA DC-8 and P-3B aircraft as its primary platforms. It seeks to understand the exchange of chemicals and aerosols between continents and the global troposphere. The constituents of interest are ozone and its precursors (hydrocarbons, NOX and HOX), aerosols, and the major greenhouse gases (CO2, CH4, N2O). INTEX-NA will provide the observational database needed to quantify inflow, outflow, and transformations of chemicals over North America. INTEX-NA is to be performed in two phases. Phase A will take place during the period of May-August 2004 and Phase B during March-June 2006. Phase A is in summer when photochemistry is most intense and climatic issues involving aerosols and carbon cycle are most pressing, and Phase B is in spring when Asian transport to North America is at its peak. INTEX-NA will coordinate its activities with concurrent measurement programs including satellites (e. g. Terra, Aura, Envisat), field activities undertaken by the North American Carbon Program (NACP), and other U.S. and international partners. However, it is being designed as a 'stand alone' mission such that its successful execution is not contingent on other programs. Synthesis of the ensemble of observation from surface, airborne, and space platforms, with the help of global/regional models is an important It is anticipated that approximately 175 flight hours for each of the aircraft (DC-8 and P-3B) will be required for each Phase. Principal operational sites are tentatively selected to be Bangor, ME; Wallops Island, VA; Seattle, WA; Rhinelander, WI; Lancaster, CA; and New Orleans, LA. These coastal and continental sites can support large missions and are suitable for INTEX-NA objectives. The experiment will be supported by forecasts from meteorological and chemical models, satellite observations, surface networks, and enhanced O3,-sonde releases. In addition to

  5. Analysis of cardiovascular responses to the H2S donors Na2S and NaHS in the rat

    PubMed Central

    Yoo, Daniel; Jupiter, Ryan C.; Pankey, Edward A.; Reddy, Vishwaradh G.; Edward, Justin A.; Swan, Kevin W.; Peak, Taylor C.; Mostany, Ricardo

    2015-01-01

    Hydrogen sulfide (H2S) is an endogenous gaseous molecule formed from L-cysteine in vascular tissue. In the present study, cardiovascular responses to the H2S donors Na2S and NaHS were investigated in the anesthetized rat. The intravenous injections of Na2S and NaHS 0.03–0.5 mg/kg produced dose-related decreases in systemic arterial pressure and heart rate, and at higher doses decreases in cardiac output, pulmonary arterial pressure, and systemic vascular resistance. H2S infusion studies show that decreases in systemic arterial pressure, heart rate, cardiac output, and systemic vascular resistance are well-maintained, and responses to Na2S are reversible. Decreases in heart rate were not blocked by atropine, suggesting that the bradycardia was independent of parasympathetic activation and was mediated by an effect on the sinus node. The decreases in systemic arterial pressure were not attenuated by hexamethonium, glybenclamide, Nw-nitro-l-arginine methyl ester hydrochloride, sodium meclofenamate, ODQ, miconazole, 5-hydroxydecanoate, or tetraethylammonium, suggesting that ATP-sensitive potassium channels, nitric oxide, arachidonic acid metabolites, cyclic GMP, p450 epoxygenase metabolites, or large conductance calcium-activated potassium channels are not involved in mediating hypotensive responses to the H2S donors in the rat and that responses are not centrally mediated. The present data indicate that decreases in systemic arterial pressure in response to the H2S donors can be mediated by decreases in vascular resistance and cardiac output and that the donors have an effect on the sinus node independent of the parasympathetic system. The present data indicate that the mechanism of the peripherally mediated hypotensive response to the H2S donors is uncertain in the intact rat. PMID:26071540

  6. Increased vacuolar Na(+)/H(+) exchange activity in Salicornia bigelovii Torr. in response to NaCl.

    PubMed

    Parks, Graham E; Dietrich, Margaret A; Schumaker, Karen S

    2002-05-01

    Shoots of the halophyte Salicornia bigelovii are larger and more succulent when grown in highly saline environments. This increased growth and water uptake has been correlated with a large and specific cellular accumulation of sodium. In glycophytes, sensitivity to salt has been associated with an inability to remove sodium ions effectively from the cytoplasm in order to protect salt-sensitive metabolic processes. Therefore, in Salicornia bigelovii efficient vacuolar sequestration of sodium may be part of the mechanism underlying salt tolerance. The ability to compartmentalize sodium may result from a stimulation of the proton pumps that provide the driving force for increased sodium transport into the vacuole via a Na(+)/H(+) exchanger. In current studies, increased vacuolar pyrophosphatase activity (hydrolysis of inorganic pyrophosphate and proton translocation) and protein accumulation were observed in Salicornia bigelovii grown in high concentrations of NaCl. Based on sodium-induced dissipation of a pyrophosphate-dependent pH gradient in vacuolar membrane vesicles, a Na(+)/H(+) exchange activity was identified and characterized. This activity is sodium concentration-dependent, specific for sodium and lithium, sensitive to methyl-isobutyl amiloride, and independent of an electrical potential. Vacuolar Na(+)/H(+) exchange activity varied as a function of plant growth in salt. The affinity of the transporter for Na(+) is almost three times higher in plants grown in high levels of salt (K(m)=3.8 and 11.5 mM for plants grown in high and low salt, respectively) suggesting a role for exchange activity in the salt adaptation of Salicornia bigelovii. PMID:11971917

  7. Two independent evolutionary routes to Na+/H+ cotransport function in membrane pyrophosphatases.

    PubMed

    Nordbo, Erika; Luoto, Heidi H; Baykov, Alexander A; Lahti, Reijo; Malinen, Anssi M

    2016-10-01

    Membrane-bound pyrophosphatases (mPPases) hydrolyze pyrophosphate (PPi) to transport H(+), Na(+) or both and help organisms to cope with stress conditions, such as high salinity or limiting nutrients. Recent elucidation of mPPase structure and identification of subfamilies that have fully or partially switched from Na(+) to H(+) pumping have established mPPases as versatile models for studying the principles governing the mechanism, specificity and evolution of cation transporters. In the present study, we constructed an accurate phylogenetic map of the interface of Na(+)-transporting PPases (Na(+)-PPases) and Na(+)- and H(+)-transporting PPases (Na(+),H(+)-PPases), which guided our experimental exploration of the variations in PPi hydrolysis and ion transport activities during evolution. Surprisingly, we identified two mPPase lineages that independently acquired physiologically significant Na(+) and H(+) cotransport function. Na(+),H(+)-PPases of the first lineage transport H(+) over an extended [Na(+)] range, but progressively lose H(+) transport efficiency at high [Na(+)]. In contrast, H(+)-transport by Na(+),H(+)-PPases of the second lineage is not inhibited by up to 100 mM Na(+) With the identification of Na(+),H(+)-PPase subtypes, the mPPases protein superfamily appears as a continuum, ranging from monospecific Na(+) transporters to transporters with tunable levels of Na(+) and H(+) cotransport and further to monospecific H(+) transporters. Our results lend credence to the concept that Na(+) and H(+) are transported by similar mechanisms, allowing the relative efficiencies of Na(+) and H(+) transport to be modulated by minor changes in protein structure during the course of adaptation to a changing environment.

  8. Investigation of sodium distribution in phosphate glasses using spin-echo {sup 23}Na NMR

    SciTech Connect

    Alam, T.M.; McLaughlin, J.; Click, C.C.; Conzone, S.; Brow, R.K.; Boyle, T.J.; Zwanziger, J.W.

    2000-02-24

    The spatial arrangements of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O{sm{underscore}bullet}(100{minus}x)P{sub 2}O{sub 5} (x {le} 55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling, and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases nonlinearly with higher sodium number density, and thus provides a measure of the Na-Na extended range order. The results of these {sup 23}Na NMR experiments are discussed within the context of several structural models, including a decimated crystal lattice model, cubic dilation lattice model, a hard sphere (HS) random distribution model, and a pairwise cluster hard sphere model. While the experimental {sup 23}Na spin-echo M{sub 2} are described adequately by both the decimated lattice and the random HS models, it is demonstrated that the slight nonlinear behavior of M{sub 2} as a function of sodium number density is more correctly described by the random distribution in the HS model. At low sodium number densities the experimental M{sub 2} is inconsistent with models incorporating Na-Na clustering. The ability to distinguish between Na-Na clusters and nonclustered distributions becomes more difficult at higher sodium concentrations.

  9. Investigation of Sodium Distribution in Phosphate Glasses Using Spin-Echo {sup 23}Na NMR

    SciTech Connect

    ALAM, TODD M.; BOYLE, TIMOTHY J.; BROW, RICHARD K.; CLICK, CAROL C.; CONZONE, SAM; McLAUGHLIN, JAY; ZWANZIGER, JOE

    1999-09-16

    The spatial arrangement of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O(100-x)P{sub 2}O{sub 5} (x<55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases non-linearly with higher sodium number density, and thus provides a measure of the Na-Na extended range order. The results of these {sup 23}Na NMR experiments are discussed within the context of several structural models, including a decimated crystal lattice model, cubic dilation lattice model, a hard sphere (HS) random distribution model and a pair-wise cluster hard sphere model. While the experimental {sup 23}Na spin-echo M{sub 2} are described adequately by both the decimated lattice and the random HS model, it is demonstrated that the slight non-linear behavior of M{sub 2} as a function of sodium number density is more correctly described by the random distribution in the HS model. At low sodium number densities the experimental M{sub 2} is inconsistent with models incorporating Na-Na clustering. The ability to distinguish between Na-Na clusters and non-clustered distributions becomes more difficult at higher sodium concentrations.

  10. Validation of estimating food intake in gray wolves by 22Na turnover

    USGS Publications Warehouse

    DelGiudice, G.D.; Duquette, L.S.; Seal, U.S.; Mech, L.D.

    1991-01-01

    We studied 22sodium (22Na) turnover as a means of estimating food intake in 6 captive, adult gray wolves (Canis lupus) (2 F, 4 M) over a 31-day feeding period. Wolves were fed white-tailed deer (Odocoileus virginianus) meat only. Mean mass-specific exchangeable Na pool was 44.8 .+-. 0.7 mEq/kg; there was no differeence between males and females. Total exchangeable Na was related (r2 = 0.85, P < 0.009) to body mass. Overall, 22Na turnover overestimated Na intake by 9.8 .+-. 2.4% after 32 days. Actual Na intake was similar in males and females; however, Na turnover (P < 0.05) and the discrepancy (P < 0.01) between turnover and actual Na intake were greater in females than males. From Day 8 to the end of the study, the absolute difference (mEq) between Na intake and Na turnover remained stable. Sodium turnover (mEq/kg/day) was a reliable (r2 = 0.91, P < 0.001) estimator of food consumption (g/kg/day) in wolves over a 32-day period. Sampling blood and weighing wolves every 1-4 days permitted identification of several potential sources of error, including changes in size of exchangeable Na pools, exchange of 22Na with gastrointestinal and bone Na, and rapid loss of the isotope by urinary excretion.

  11. Effect of NaCl and Na2SO4 on the biodecolourization of K-2BP by Halomonas sp. GYW

    PubMed Central

    Lian, Jing; Xu, Zhifang; Guo, Jianbo; Yue, Lin; Guo, Yankai; Zhang, Chenxiao; Yang, Jingliang

    2014-01-01

    In this paper, the effect of NaCl and Na2SO4 on the biodecolourization of reactive brilliant red K-2BP by a Halomonas sp. GYW (EF188281) was investigated in details. The decolourisation efficiency and the oxidation–reduction potential (ORP) change were explored during the decolourization process. The results from sequencing batch tests showed that Na2SO4 influenced the decolourization efficiency more slightly than NaCl in different synthetic dye solutions with different mixtures of Na2SO4 and NaCl. In the dye solutions with the same salt concentration or the same Na+ concentration, high Na2SO4 concentration did not inhibit the decolourization process and even stimulated the decolourization efficiency of reactive brilliant red K-2BP. Compared to NaCl system, the addition of Na2SO4 increased the ORP values about 35 mV, which agreed with the theoretic analysis of Gibbs function. This study improved our knowledge of azo dye decolourization under high salinity conditions and provided efficient option for the treatment of azo dye wastewater. PMID:27594796

  12. Heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(s)

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun; Timonen, Raimo S.; Keyser, Leon F.; Yung, Yuk L.

    1995-01-01

    The heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) (eq 1) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(S) (eq 2) were investigated over the temperature range 223-296 K in a flow-tube reactor coupled to a quadrupole mass spectrometer. Either a chemical ionization mass spectrometer (CIMS) or an electron-impact ionization mass spectrometer (EIMS) was used to provide suitable detection sensitivity and selectivity. In order to mimic atmospheric conditions, partial pressures of HNO3 and N2O5 in the range 6 x 10(exp -8) - 2 x 10(exp -6) Torr were used. Granule sizes and surface roughness of the solid NaCl substrates were determined by using a scanning electron microscope. For dry NaCl substrates, decay rates of HNO3 were used to obtain gamma(1) = 0.013 +/- 0.004 (1sigma) at 296 K and > 0.008 at 223 K, respectively. The error quoted is the statistical error. After all corrections were made, the overall error, including systematic error, was estimated to be about a factor of 2. HCl was found to be the sole gas-phase product of reaction 1. The mechanism changed from heterogeneous reaction to predominantly physical adsorption when the reactor was cooled from 296 to 223 K. For reaction 2 using dry salts, gamma(2) was found to be less than 1.0 x 10(exp -4) at both 223 and 296 K. The gas-phase reaction product was identified as ClNO2 in previous studies using an infrared spectrometer. An enhancement in reaction probability was observed if water was not completely removed from salt surfaces, probably due to the reaction of N2O5(g) + H2O(s) yields 2HNO3(g). Our results are compared with previous literature values obtained using different experimental techniques and conditions. The implications of the present results for the enhancement of the hydrogen chloride column density in the lower stratosphere after the El Chichon volcanic eruption and for the chemistry of HCl and HNO3 in the marine troposphere are discussed.

  13. "Oxygen Sensing" by Na,K-ATPase: These Miraculous Thiols.

    PubMed

    Bogdanova, Anna; Petrushanko, Irina Y; Hernansanz-Agustín, Pablo; Martínez-Ruiz, Antonio

    2016-01-01

    Control over the Na,K-ATPase function plays a central role in adaptation of the organisms to hypoxic and anoxic conditions. As the enzyme itself does not possess O2 binding sites its "oxygen-sensitivity" is mediated by a variety of redox-sensitive modifications including S-glutathionylation, S-nitrosylation, and redox-sensitive phosphorylation. This is an overview of the current knowledge on the plethora of molecular mechanisms tuning the activity of the ATP-consuming Na,K-ATPase to the cellular metabolic activity. Recent findings suggest that oxygen-derived free radicals and H2O2, NO, and oxidized glutathione are the signaling messengers that make the Na,K-ATPase "oxygen-sensitive." This very ancient signaling pathway targeting thiols of all three subunits of the Na,K-ATPase as well as redox-sensitive kinases sustains the enzyme activity at the "optimal" level avoiding terminal ATP depletion and maintaining the transmembrane ion gradients in cells of anoxia-tolerant species. We acknowledge the complexity of the underlying processes as we characterize the sources of reactive oxygen and nitrogen species production in hypoxic cells, and identify their targets, the reactive thiol groups which, upon modification, impact the enzyme activity. Structured accordingly, this review presents a summary on (i) the sources of free radical production in hypoxic cells, (ii) localization of regulatory thiols within the Na,K-ATPase and the role reversible thiol modifications play in responses of the enzyme to a variety of stimuli (hypoxia, receptors' activation) (iii) redox-sensitive regulatory phosphorylation, and (iv) the role of fine modulation of the Na,K-ATPase function in survival success under hypoxic conditions. The co-authors attempted to cover all the contradictions and standing hypotheses in the field and propose the possible future developments in this dynamic area of research, the importance of which is hard to overestimate. Better understanding of the processes

  14. Fusion of Na-ASP-2 with human immunoglobulin Fcγ abrogates histamine release from basophils sensitized with anti-Na-ASP-2 IgE.

    PubMed

    Zhan, Bin; Santiago, H; Keegan, B; Gillespie, P; Xue, J; Bethony, J; de Oliveira, L M; Jiang, D; Diemert, D; Xiao, S-H; Jones, K; Feng, X; Hotez, P J; Bottazzi, M E

    2012-01-01

    Na-ASP-2 is a major protein secreted by infective third-stage larvae (L3) of the human hookworm Necator americanus upon host entry. It was chosen as a lead vaccine candidate for its ability to elicit protective immune responses. However, clinical development of this antigen as a recombinant vaccine was halted because it caused allergic reactions among some of human volunteers previously infected with N. americanus. To prevent IgE-mediated allergic reactions induced by Na-ASP-2 but keep its immunogenicity as a vaccine antigen, we designed and tested a genetically engineered fusion protein, Fcγ/Na-ASP-2, composed of full-length Na-ASP-2 and truncated human IgG Fcγ1 that targets the negative signalling receptor FcγRIIb expressed on pro-allergic cells. The chimeric recombinant Fcγ/Na-ASP-2 protein was expressed in Pichia pastoris and shared the similar antigenicity as native Na-ASP-2. Compared to Na-ASP-2, the chimeric fusion protein efficiently reduced the release of histamine in human basophils sensitized with anti-Na-ASP-2 IgE obtained from individuals living in a hookworm-endemic area. In dogs infected with canine hookworm, Fcγ/Na-ASP-2 resulted in significantly reduced immediate-type skin reactivity when injected intradermally compared with Na-ASP-2. Hamsters vaccinated with Fcγ/Na-ASP-2 formulated with Alhydrogel(®) produced specific IgG that recognized Na-ASP-2 and elicited similar protection level against N. americanus L3 challenge as native Na-ASP-2.

  15. NaN, a novel voltage-gated Na channel, is expressed preferentially in peripheral sensory neurons and down-regulated after axotomy

    PubMed Central

    Dib-Hajj, S. D.; Tyrrell, L.; Black, J. A.; Waxman, S. G.

    1998-01-01

    Although physiological and pharmacological evidence suggests the presence of multiple tetrodotoxin-resistant (TTX-R) Na channels in neurons of peripheral nervous system ganglia, only one, SNS/PN3, has been identified in these cells to date. We have identified and sequenced a novel Na channel α-subunit (NaN), predicted to be TTX-R and voltage-gated, that is expressed preferentially in sensory neurons within dorsal root ganglia (DRG) and trigeminal ganglia. The predicted amino acid sequence of NaN can be aligned with the predicted structure of known Na channel α-subunits; all relevant landmark sequences, including positively charged S4 and pore-lining SS1–SS2 segments, and the inactivation tripeptide IFM, are present at predicted positions. However, NaN exhibits only 42–53% similarity to other mammalian Na channels, including SNS/PN3, indicating that it is a novel channel, and suggesting that it may represent a third subfamily of Na channels. NaN transcript levels are reduced significantly 7 days post axotomy in DRG neurons, consistent with previous findings of a reduction in TTX-R Na currents. The preferential expression of NaN in DRG and trigeminal ganglia and the reduction of NaN mRNA levels in DRG after axonal injury suggest that NaN, together with SNS/PN3, may produce TTX-R currents in peripheral sensory neurons and may influence the generation of electrical activity in these cells. PMID:9671787

  16. NaCl does not affect hypothalamic noradrenergic input in deoxycorticosterone acetate/NaCl and Dahl salt-sensitive rats.

    PubMed

    Chen, Y F; Meng, Q C; Wyss, J M; Jin, H K; Rogers, C F; Oparil, S

    1990-07-01

    Previous studies from our laboratories demonstrated that dietary NaCl supplementation in NaCl-sensitive spontaneously hypertensive rats elevates blood pressure, increases peripheral sympathetic nervous system activity, and depresses endogenous norepinephrine stores and turnover in the anterior hypothalamus. These findings suggest that reduced noradrenergic input to sympathoinhibitory neurons in anterior hypothalamus contributes to NaCl-sensitive hypertension in spontaneously hypertensive rats. The current study tested the hypothesis that dietary NaCl supplementation depresses endogenous norepinephrine stores and turnover in anterior hypothalamus of two other NaCl-sensitive models of hypertension, the Dahl salt-sensitive rat and the deoxycorticosterone acetate/NaCl hypertensive rat, thus increasing blood pressure by reducing noradrenergic input to the anterior hypothalamus. Dahl salt-sensitive rats were fed a high (8%) NaCl diet, and deoxycorticosterone acetate/NaCl rats rats drank 1% NaCl solution ad libitum for 2 or 4 weeks. Age-matched Dahl salt-sensitive rats fed a basal 1% NaCl diet and uninephrectomized Sprague-Dawley rats drinking tap water were controls. Regional brain catecholamines were determined by high-performance liquid chromatography with electrochemical detection. Norepinephrine turnover in hypothalamus (anterior, posterior, and ventral regions) and brain stem (pons and medulla) was assessed using the dopamine beta-hydroxylase inhibitor 1-cyclohexyl-2-mercapto-imidazole. High NaCl treatment caused significant elevations in blood pressure in Dahl salt-sensitive and deoxycorticosterone acetate/NaCl rats, but endogenous norepinephrine levels and turnover rates were not significantly different in anterior hypothalamus or any other brain region studied between the NaCl-supplemented and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Sequential growth of sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell-shell nanoparticles for photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Peng, Huang-Yong; Ding, Bin-Bin; Ma, Yin-Chu; Sun, Shi-Qi; Tao, Wei; Guo, Yan-Chuan; Guo, Hui-Chen; Yang, Xian-Zhu; Qian, Hai-Sheng

    2015-12-01

    Upconversion (UC) nanostructures have attracted much interest for their extensive biological applications. In this work, we describe a sequential synthetic route to prepare sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell upconversion nanoparticles. The as-prepared products were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM, JEM 2100F), respectively. The as-prepared core-shell nanoparticles of NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb are composed of elliptical nanoparticles with a length of 80 nm and width of 42 nm, which show efficient upconversion fluorescence excited at 808 nm indicating the formation of core-shell-shell sandwiched nanostructures. In addition, the as-prepared sandwiched NaYF4:Yb/Er@NaYF4:Yb@NaNdF4:Yb core-shell upconversion nanoparticles also show strong upconversion fluorescence excited at 980 nm. Amphiphilic mPEG2k-b-PEBEP6K copolymers (denoted as PPE) were chosen to transfer these hydrophobic UCNPs into the aqueous phase for biological application. In vitro photodynamic therapy of cancer cells show that the viability of cells incubated with the nanoparticles loaded with MC 540 was significantly lower as compared to the nanoparticles without photosensitizers exposed to NIR laser.

  18. Synthesis and structures of type-I clathrates: Rb6Na2Ge44.89(1), Cs6Na2Zn4Ge42 and Cs6.40(1)Na1.60(1)Ga8Ge38

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Mu, Gang; Huang, Fuqiang; Xie, Xiaoming

    2016-10-01

    Type-I clathrates of Rb6Na2Ge44.89(1), Cs6Na2Zn4Ge42 and Cs6.40(1)Na1.60(1)Ga8Ge38 were synthesized via solid-state reaction. Rb6Na2Ge44.89(1), Cs6Na2Zn4Ge42 and Cs6.40(1)Na1.60(1)Ga8Ge38 were found to crystalize in the cubic space group of Pm 3 ̅ n with lattice parameters of a=10.72755(5) Å, a=10.79501(8) Å and a=10.79726(5) Å, respectively. Theoretical calculations indicated semiconducting features for the calculation models of Rb6Na2Ge44, Cs6Na2Zn4Ge42 and Cs6Na2Ga8Ge38 with band gaps of 0.002 eV, 0.297 eV and 0.221 eV, respectively.

  19. The influence of beta subunit structure on the interaction of Na+/K(+)-ATPase complexes with Na+. A chimeric beta subunit reduces the Na+ dependence of phosphoenzyme formation from ATP.

    PubMed

    Eakle, K A; Lyu, R M; Farley, R A

    1995-06-01

    High-affinity ouabain binding to Na+/K(+)-ATPase (sodium- and potassium-transport adenosine triphosphatase (EC 3.6.1.37)) requires phosphorylation of the alpha subunit of the enzyme either by ATP or by inorganic phosphate. For the native enzyme (alpha/beta 1), the ATP-dependent reaction proceeds about 4-fold more slowly in the absence of Na+ than when saturating concentrations of Na+ are present. Hybrid pumps were formed from either the alpha 1 or the alpha 3 subunit isoforms of Na+/K(+)-ATPase and a chimeric beta subunit containing the transmembrane segment of the Na+/K(+)-ATPase beta 1 isoform and the external domain of the gastric H+/K(+)-ATPase beta subunit (alpha/NH beta 1 complexes). In the absence of Na+, these complexes show a rate of ATP-dependent ouabain binding from approximately 75-100% of the rate seen in the presence of Na+ depending on buffer conditions. Nonhydrolyzable nucleotides or treatment of ATP with apyrase abolishes ouabain binding, demonstrating that ouabain binding to alpha/NH beta 1 complexes requires phosphorylation of the protein. Buffer ions inhibit ouabain binding by alpha/NH beta 1 in the absence of Na+ rather than promote ouabain binding, indicating that they are not substituting for sodium ions in the phosphorylation reaction. The pH dependence of ATP-dependent ouabain binding in the presence or absence of Na+ is similar, suggesting that protons are probably not substituting for Na+. Hybrid alpha/NH beta 1 pumps also show slightly higher apparent affinities (2-3-fold) for ATP, Na+, and ouabain; however, these are not sufficient to account for the increase in ouabain binding in the absence of Na+. In contrast to phosphoenzyme formation and ouabain binding by alpha/NH beta 1 complexes in the absence of Na+, ATPase activity, measured as release of phosphate from ATP, requires Na+. These data suggest that the transition from E1P to E2P during the catalytic cycle does not occur when the sodium binding sites are not occupied. Thus, the

  20. Na+ accumulation in root symplast of sunflower plants exposed to moderate salinity is transpiration-dependent.

    PubMed

    Quintero, José Manuel; Fournier, José María; Benlloch, Manuel; Rodríguez-Navarro, Alonso

    2008-08-25

    Twenty-day-old sunflower plants (Helianthus annuus L. cv Sun-Gro 380) grown hydroponically under controlled conditions were used to study the effect of transpiration on Na(+) compartmentalization in roots. The plants were exposed to low Na(+) concentrations (25 mM NaCl) and different environmental humidity conditions over a short time period (8.5 h). Under these conditions, Na(+) was accumulated primarily in the root, but only the Na(+) accumulated in the root symplast was dependent on transpiration, while the Na(+) accumulated in both the shoot and the root apoplast exhibited a low transpiration dependence. Moreover, Na(+) content in the root apoplast was reached quickly (0.25 h) and increased little with time. These results suggest that, in sunflower plants under moderate salinity conditions, Na(+) uptake in the root symplast is mediated by a transport system whose activity is enhanced by transpiration. PMID:18166246