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Sample records for alkylbenzene sulphonate las

  1. Effect of linear alkylbenzene sulphonates (LAS) on the anaerobic digestion of sewage sludge.

    PubMed

    Garcia, M T; Campos, E; Sánchez-Leal, J; Ribosa, I

    2006-08-01

    Batch anaerobic biodegradation tests with different alkylbenzene sulphonates (LAS) at increasing concentrations were performed in order to investigate the effect of LAS homologues on the anaerobic digestion process of sewage sludge. Addition of LAS homologues to the anaerobic digesters increased the biogas production at surfactant concentrations 5-10 g/kg dry sludge and gave rise to a partial or total inhibition of the methanogenic activity at higher surfactant loads. Therefore, at the usual LAS concentration range in sewage sludge, no adverse effects on the anaerobic digesters functioning of a wastewater treatment plant (WWTP) can be expected. The increase of biogas production at low surfactant concentrations was attributed to an increase of the bioavailability and subsequent biodegradation of organic pollutants associated with the sludge, promoted by the surfactant adsorption at the solid/liquid interface. When the available surfactant fraction in the aqueous phase instead of the nominal surfactant concentration was used to evaluate the toxicity of LAS homologues, a highly significant relationship between toxicity and alkyl chain length was obtained. Taking into account the homologue distribution of commercial LAS in the liquid phase of the anaerobic digesters of a WWTP, an EC(50) value of 14 mg/L can be considered for LAS toxicity on the anaerobic microorganisms.

  2. Effect of linear alkylbenzene sulphonate (LAS) on non-specific defence mechanisms in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Bakirel, Tülay; Keleş, Oya; Karataş, Süheyla; Ozcan, Mukaddes; Türkmen, Gülhan; Candan, Akin

    2005-01-26

    Linear alkylbenzene sulphonate (LAS) is among the most widely disseminated xenobiotics to enter waste streams and the aquatic environment. In the present investigation, we present a novel approach to evaluate in toxicity of LAS. The effects of sublethal levels (0.2 and 0.4 mg/l) of LAS on non-specific immune system, phagocytosis, respiratory burst and lyzosyme activity, and specific growth rate in the rainbow trout, Oncorhynchus mykiss, during a 54-day exposure were examined by a static bioassay test procedure. The phagocytic activity of leukocytes from fish exposed to 0.4 mg/l LAS statistically decreased compared with the control fish values. No significant reductions were observed in the extra-intracellular respiratory burst and lysozyme activities after exposure to LAS at any of the concentrations tested. The final body weight in fish groups exposed to the LAS were found to be significantly lower than in the control. The specific growth rate results also supported the result above. The results of this study showed sublethal doses (0.2-0.4 mg/l) of LAS caused to statistically insignificant suppression of non-specific immune system mechanisms excluding phagocytosis in fish at laboratory conditions. These doses of LAS may produce potential synergism on immune system when presented with other environmental pollutants.

  3. Characteristics of Combined Submerged Membrane Bioreactor with Granular Activated Carbon (GAC) in Treating Lineal Alkylbenzene Sulphonates (LAS) Wastewater

    NASA Astrophysics Data System (ADS)

    Guo, Jifeng; Xia, Siqing; Lu, Yanjun

    2010-11-01

    A combined MBR (cMBR) with granular activated carbon (GAC) was used as a backbone system to treat the synthetic lineal alkylbenzene sulphonates (LAS) wastewater. The GAC was added in the MBR to improve the resistance of membrane fouling. A parallel conventional MBR (pMBR) without the GAC was run to give a contrast. The results of the process demonstrate that the cMBR process was more efficient than pMBR. It was found that the TMP changes of the cMBR were slower than the pMBR. The results demonstrated that the cMBRs membrane was better than the pMBR's after a clean period run. It was the GAC scrubbing to the membrane that delayed the membrane fouling of the cMBR. Variable critical flux was found in MBR, which showed that the cMBR could make the critical flux better than pMBR in the run time, but GAC could not improve the critical flux at the end of the period for the severe membrane fouling. Based on this theory, a variable critical flux (J) of MBR was put forward, and the relationship of J with time (t) was: J = 16.081e-0.0177t.

  4. MBAS (Methylene Blue Active Substances) and LAS (Linear Alkylbenzene Sulphonates) in Mediterranean coastal aerosols: Sources and transport processes

    NASA Astrophysics Data System (ADS)

    Becagli, S.; Ghedini, C.; Peeters, S.; Rottiers, A.; Traversi, R.; Udisti, R.; Chiari, M.; Jalba, A.; Despiau, S.; Dayan, U.; Temara, A.

    2011-12-01

    Methylene Blue Active Substances (MBAS) and Linear Alkylbenzene Sulphonates (LAS) concentrations, together with organic carbon and ions were measured in atmospheric coastal aerosols in the NW Mediterranean Basin. Previous studies have suggested that the presence of surfactants in coastal aerosols may result in vegetation damage without specifically detecting or quantifying these surfactants. Coastal aerosols were collected at a remote site (Porquerolles Island-Var, France) and at a more anthropised site (San Rossore National Park-Tuscany, Italy). The chemical data were interpreted according to a comprehensive local meteorological analysis aiming to decipher the airborne source and transport processes of these classes of compounds. The LAS concentration (anthropogenic surfactants) was measured in the samples using LC-MS/MS, a specific analytical method. The values were compared with the MBAS concentration, determined by a non-specific analytical method. At Porquerolles, the MBAS concentration (103 ± 93 ng m -3) in the summer samples was significantly higher than in the winter samples. In contrast, LAS concentrations were rarely greater than in the blank filters. At San Rossore, the mean annual MBAS concentration (887 ± 473 ng m -3 in PM10) contributed about 10% to the total atmospheric particulate organic matter. LAS mean concentration in these same aerosol samples was 11.5 ± 10.5 ng m -3. A similar MBAS (529 ± 454 ng m -3) - LAS (7.1 ± 4.1 ng m -3 LAS) ratio of ˜75 was measured in the fine (PM2.5) aerosol fraction. No linear correlation was found between MBAS and LAS concentrations. At San Rossore site the variation of LAS concentrations was studied on a daily basis over a year. The LAS concentrations in the coarse fraction (PM10-2.5) were higher during strong sea storm conditions, characterized by strong air flow coming from the sea sector. These events, occurring with more intensity in winter, promoted the formation of primary marine aerosols containing LAS

  5. The aquatic toxicity of anionic surfactants to Daphnia magna--a comparative QSAR study of linear alkylbenzene sulphonates and ester sulphonates.

    PubMed

    Hodges, Geoff; Roberts, David W; Marshall, Stuart J; Dearden, John C

    2006-06-01

    This paper develops quantitative structure activity relationships (QSARs) for the acute aquatic toxicity of the anionic surfactants linear alkylbenzene sulphonates (LAS) and ester sulphonates (ES) to Daphnia magna, the aim being to investigate the modes of action by comparing the QSARs for the two types of surfactant. The generated data for ES have been used to develop a QSAR correlating toxicity with calculated log P values: log(1/EC50)= 0.78 log P+1.37. This equation has an intercept 1.1 log units lower than a QSAR for linear alkylbenzene sulphonates (LAS). The findings suggest that either ES surfactants act by a different mode of action to LAS and other anionic surfactants or the log P calculation method introduces a systematic overestimate when applied to ES.

  6. Derivation of predicted no effect concentrations (PNEC) for marine environmental risk assessment: application of different approaches to the model contaminant Linear Alkylbenzene Sulphonates (LAS) in a site-specific environment.

    PubMed

    Hampel, M; González-Mazo, E; Vale, C; Blasco, J

    2007-05-01

    Four sediment-dwelling marine organisms were exposed to sediments spiked with increasing concentrations of Linear Alkylbenzene Sulphonate (LAS). The selected endpoint mortality was reported daily and acute LC(50) (96 h), as well as final LC(10) values were calculated for the derivation of environmentally safe predicted no effect concentrations (PNEC) for the sediment compartment. PNECs were estimated by both application of assessment factors (AF) and the equilibrium partitioning method (EPM) as proposed by the EU TGD. Finally, environmental risk assessment in a site-specific environment, the Sancti Petri Channel, South Iberian Peninsula, was carried out at three different sampling stations with known environmental LAS concentrations. PNECs obtained by the assessment factor approach with acute toxicity data were one to two orders of magnitude lower than those from the equilibrium partitioning method. On the other hand, when applying lower AFs to the estimated LC(10) values, the PNECs obtained by both approaches were more similar. Environmental risk assessment carried out with the estimated PNECs in a site specific environment with known sediment LAS concentrations revealed that PNECs obtained with acute toxicity data were over conservative whereas those obtained with AF=10 on LC(10) data and EPM produced more realistic results in accordance with field observations carried out in the study area.

  7. Risk assessment of linear alkylbenzene sulphonates, LAS, in agricultural soil revisited: robust chronic toxicity tests for Folsomia candida (Collembola), Aporrectodea caliginosa (Oligochaeta) and Enchytraeus crypticus (Enchytraeidae).

    PubMed

    Krogh, Paul Henning; Lopez, Coral Verge; Cassani, Giorgio; Jensen, John; Holmstrup, Martin; Schraepen, Nathalie; Jørgensen, Elin; Gavor, Zdenek; Temara, Ali

    2007-10-01

    To obtain robust data on the toxicity of LAS, tests with the collembolan Folsomia candida L., the oligochaetes Aporrectodea caliginosa Savigny (earthworm) and Enchytraeus crypticus Westheide and Graefe (enchytraeid) were performed in a sandy loam soil. Additionally limited tests with LAS spiked to sewage sludge, and subsequently mixed into soil, were performed. For the endpoint of interest, reproduction in soil, we found an EC10 of 205 mg LAS kg(-1) soil [8.6-401] [95% confidence limits] for F. candida and an EC10 of 46 mg LAS kg(-1) soil [13-80] for A. caliginosa after 28 days. E. crypticus was not affected by concentrations up to 120 mg LAS kg(-1) soil. When adding (low contaminated) non-spiked sludge to soil, high stimulation of reproduction was observed for E. crypticus and A. caliginosa but not for F. candida. We argue that this difference in stimulative response between the tested species is related to the difference in feeding behaviour. Sludge spiked with LAS did not significantly affect the reproduction of F. candida (fertility: number of juvenile offspring) and A. caliginosa (fecundity: number of cocoons) (dose equivalent to 181 g and 91 g LAS kg(-1) sludge, respectively). Significantly reduced reproduction was observed for E. crypticus (at 120 mg LAS kg(-1) soil+sludge corresponding to 72 g LAS kg(-1) sludge) compared to non-spiked sludge. The reproduction by E. crypticus was, however, comparable to the reproduction observed in the control soil without sludge. Compared to LAS directly spiked to soil, the reproductive output of organisms exposed to spiked sludge was either not significantly different (F. candida, E. crypticus) or significantly improved (A. caliginosa). More studies are needed in order to make firm conclusions on the potential effect of artificially contaminated sludge in soil systems.

  8. [A new species of the genus Phenylobacterium for the degradation of LAS (linear alkylbenzene sulfonate)].

    PubMed

    Ke, Na; Xiao, Changsong; Ying, Qifeng; Ji, Shulan

    2003-02-01

    A strain GZ6 that can biodegrade LAS (Linear Alkylbenzene Sulphonate) is identified. It is aerobic gram-negative rod or short-rod (0.5 to 0.8 by 1.0 to 2.0 Mm). It is mobile with a single polar flagellum. Optimum growth occurred at 30 degrees C and pH7.0. It is catalase positive, urease positive, and arginine decarboxylase positive. All the other physiological and biochemical tests performed were negative. It utilizes the xenobiotic compounds chloridazon, antipyrin and LAS as sole carbon sources. Most sugars, alcohols, and carboxylic acids are not utilized. It has Q-10 as the major quinone. The main cell fatty acids are Sum7, C16:0 and Sum4. The DNA G + C mol % content is 70.10. A phylogenic tree was constructed on the basis of 16S rDNA sequences. It showed that the previously known member of the genus Phenylobacterium, Phenylobacterium mobile DSM1986T, is the nearest neighbor to strain GZ6. The level of binary sequence similarity between them is 97.49%. And the DNA-DNA relatedness is 40%. These genetic analysis and their morphological difference show that they are different species of Phenylobacterium. A new species, Phenylobacterium mobile sp. nov., has been proposed.

  9. Fate of linear alkylbenzene sulfonate (LAS) in activated sludge plants.

    PubMed

    Temmink, H; Klapwijk, Bram

    2004-02-01

    Monitoring data were collected in a pilot-scale municipal activated sludge plant to assess the fate of the C12-homologue of linear alkyl benzene sulfonate (LAS-C12). The pilot-plant was operated at influent LAS-C12 concentrations between 2 and 12 mg l(-1) and at sludge retention times of 10 and 27 days. Effluent and waste sludge concentrations varied between 5 and 10 microg l(-1) and between 37 and 69 microg g(-1) VSS, respectively. In the sludge samples only 2-8% was present as dissolved LAS-C12, whereas the remaining 92-98% was found to be adsorbed to the sludge. In spite of this high degree of sorption, more than 99% of the LAS-C12 load was removed by biodegradation, showing that not only the soluble fraction but also the adsorbed fraction of LAS-C12 is readily available for biodegradation. Sorption and biodegradation of LAS-C12 were also investigated separately. Sorption was an extremely fast and reversible process and could be described by a linear isotherm with a partition coefficient of 3.2 l g(-1) volatile suspended solids. From the results of biodegradation kinetic tests it was concluded that primary biodegradation of LAS-C12 cannot be described by a (growth) Monod model, but a secondary utilisation model should be used instead. The apparent affinity of the sludge to biodegrade LAS-C12 increased when the sludge was loaded with higher influent concentrations of LAS-C12.

  10. Anaerobic degradation pathway of linear Alkylbenzene sulfonates (LAS) in sulfate-reducing marine sediments.

    PubMed

    Lara-Martín, Pablo A; Gómez-Parra, Abelardo; Sanz, José Luis; González-Mazo, Eduardo

    2010-03-01

    Linear alkylbenzene sulfonates (LAS) are among the principal synthetic surfactants used worldwide. Their presence in the environment has been reported in a significant number of studies, and it has been generally assumed that LAS are not biotransformed in the absence of oxygen. However, laboratory experiments performed by our group using anoxic marine sediments have reported LAS degradation percentages that can reach up to 79% in 165 days. Here, we show for the first time the initial reaction metabolites (generated via fumarate addition to the LAS molecules), their biotransformation into sulfophenyl carboxylic acids (SPC), and the progressive degradation of these by successive beta-oxidation reactions. Advanced mass spectrometry has been used to carry out the identification of these compounds. This is the first time that an anaerobic degradation pathway for LAS is described, and these results represent a significant advance in understanding the final fate of these and other similar compounds in anoxic environments.

  11. Anaerobic bioprocessing of sewage sludge, focusing on degradation of linear alkylbenzene sulfonates (LAS).

    PubMed

    Angelidaki, I; Toräng, L; Waul, C M; Schmidt, J E

    2004-01-01

    Anaerobic degradation of sludge amended with linear alkylbenzene sulfonates (LAS) was tested in a one stage continuous stirred tank reactor (CSTR) and a two stage reactor system consisting of a CSTR as first step and upflow anaerobic sludge bed (UASB) reactor as the second step. Anaerobic removal of LAS was only observed at the second step but not at the first step. Removal of LAS in the UASB reactors was approx. 80% where half was due to absorption and the other half was apparently due to biological removal as shown from the LAS mass balance. At the end of the experiment the reactors were spiked with 14C-LAS which resulted in 5.6% 14CO2 in the produced gas. Total mass balance of the radioactivity was however not achieved. In batch experiments it was found that LAS at concentrations higher than 50 mg/l is inhibitory for most microbial groups of the anaerobic process. Therefore, low initial LAS concentration is a prerequisite for successful LAS degradation. The results from the present study suggest that anaerobic degradation of LAS is possible in UASB reactors when the concentration of LAS is low enough to avoid inhibition of microorganisms active in the anaerobic process.

  12. Methanogenic activity inhibition by increasing the linear alkylbenzene sulfonate (LAS) concentration.

    PubMed

    Souza, Luiza F C; Florencio, Lourdinha; Gavazza, Savia; Kato, Mario T

    2016-07-02

    The effect of the initial concentration of linear alkylbenzene sulfonate (LAS) on specific methanogenic activity (SMA) was investigated in this work. Six anaerobic flasks reactors with 1 L of total volume were inoculated with anaerobic sludge (2 g VSS L(-1)). The reactors were assayed for 42 days, and fed with volatile fatty acids, nutrients, and LAS. The initial LAS concentrations were 0, 10, 30, 50, 75, and 100 mg L(-1) for the treatment flasks T1 (control), T2, T3, T4, T5, and T6, respectively. When compared with T1, T2 exhibited a 30% reduction in maximum SMA and total methane production (TMP). In treatment T3 through T6, the reductions were 44-97% (T3-T6) for SMA, and 30-90% (T3-T6) for TMP. Total LAS removal increased following the increase in the initial LAS concentration (from 36% at T1 to 76% at T6), primarily due to the high degree of sludge adsorption. LAS biodegradation also occurred (32% in all treatments), although this was most likely associated with the formation of non-methane intermediates. Greater removal by adsorption was observed in long-chain homologues, when compared to short-chain homologues (C13 > C10), whereas the opposite occurred for biodegradation (C10 > C13). The C13 homologue was adsorbed to a great extent (in mass) in T4, T5 and T6, and may also have inhibited methane formation in these treatments.

  13. Evaluation of Linear Alkylbenzene Sulfonate (LAS) behaviour in agricultural soil through laboratory continuous studies.

    PubMed

    Oliver-Rodríguez, B; Zafra-Gómez, A; Reis, M S; Duarte, B P M; Verge, C; de Ferrer, J A; Pérez-Pascual, M; Vílchez, J L

    2015-07-01

    The behaviour of Linear Alkylbenzene Sulfonate (LAS) in agricultural soil is investigated in the laboratory using continuous-flow soil column studies in order to simultaneously analyze the three main underlying phenomena (adsorption/desorption, degradation and transport). The continuous-flow soil column experiments generated the breakthrough curves for each LAS homologue, C10, C11, C12 and C13, and by adding them up, for total LAS, from which the relevant retention, degradation and transport parameters could be estimated, after proposing adequate models. Several transport equations were considered, including the degradation of the sorbate in solution and its retention by soil, under equilibrium and non-equilibrium conditions between the sorbent and the sorbate. In general, the results obtained for the estimates of those parameters that were common to the various models studied (such as the isotherm slope, first order degradation rate coefficient and the hydrodynamic dispersion coefficient) were rather consistent, meaning that mass transfer limitations are not playing a major role in the experiments. These three parameters increase with the length of the LAS homologue chain. The study will provide the underlying conceptual framework and fundamental parameters to understand, simulate and predict the environmental behaviour of LAS compounds in agricultural soils.

  14. Effect of linear alkylbenzene sulfonate (LAS) on human intestinal Caco-2 cells at non cytotoxic concentrations.

    PubMed

    Bradai, Mohamed; Han, Junkyu; Omri, Abdelfatteh El; Funamizu, Naoyuki; Sayadi, Sami; Isoda, Hiroko

    2016-08-01

    Linear alkylbenzene sulfonate (LAS) is a cytotoxic synthetic anionic surfactant widely present in the environment due to its large-scale production and intensive use in the detergency field. In this study, we investigated the effect of LAS (CAS No. 25155-30-0) at non cytotoxic concentrations on human intestinal Caco-2 cells using different in vitro bioassays. As results, LAS increased Caco-2 cell proliferation at concentrations ranging from 1 to 15 ppm, more significantly for shorter exposure time (24 h), confirmed using flow cytometry and trypan blue exclusion methods. Moreover, proteomics analysis revealed that this effect was associated with an over-expression of elongation factor 2 and dipeptidyl peptidase 3, and a down-regulation of 14-3-3 protein theta, confirmed at mRNA level using real-time PCR. These findings suggest that LAS at non cytotoxic concentrations, similar to those observed at wastewater treatment plants outlets, increases the growth rate of colon cancer cells, raising thereby its tumor promotion effect potential.

  15. Effects of linear alkylbenzene sulfonate (LAS) on the interspecific competition between Microcystis and Scenedesmus.

    PubMed

    Zhu, Wei; Chen, Huaimin; Guo, Lili; Li, Ming

    2016-08-01

    The widespread use of detergents increases the concentration of surfactant in lakes and reservoirs. High surfactant loads produces toxicity to algae; however, the influence of the increasing surfactant on the competition between algae is not clear. In this paper, different amounts of linear alkylbenzene sulfonate (LAS) were added to test the effects of LAS on the competition between Microcystis aeruginosa and Scenedesmus obliquus under eutrophic condition. In single culture, the growth of S. obliquus was promoted under lower LAS concentrations (1 and 20 mg L(-1)), but cell density of S. obliquus reduced when treated with higher LAS concentration (100 mg L(-1)). The growth of M. aeruginosa was inhibited markedly with 20 and 100 mg L(-1) LAS. Compared with single culture, the result was opposite in co-cultures and the cell density of S. obliquus increased significantly when treated with LAS of 1, 20, and 100 mg L(-1). The specific growth rates of S. obliquus and M. aeruginosa in both cultures were 0.4-0.5 day(-1) and 0.6-0.7 day(-1), respectively, except that the specific growth rate of M. aeruginosa in both cultures treated with 100 mg L(-1) LAS was about 0.2 day(-1). M. aeruginosa dominated over S. obliquus in the co-culture without LAS, while the competition was completely opposite with the addition of 20 mg L(-1) LAS. The growth of S. obliquus treated with 20 mg L(-1) LAS was not affected significantly in single culture but was promoted by 75 % in co-culture. Moreover, the growth of S. obliquus in co-culture treated with 100 mg L(-1) LAS was promoted by more than 97 %. These results suggested that the increasing LAS would overturn the competition of algae in freshwater ecosystems.

  16. Bioconcentration of the anionic surfactant linear alkylbenzene sulfonate (LAS) in the marine shrimp Palaemonetes varians: a radiotracer study.

    PubMed

    Renaud, Florent; Warnau, Michel; Oberhänsli, François; Teyssié, Jean-Louis; Temara, Ali; Rouleau, Claude; Metian, Marc

    2014-08-15

    Uptake and depuration kinetics of dissolved [(14)C]C₁₂-6-linear alkylbenzene sulfonate (LAS) were determined in the shrimp Palaemonetes varians using environmentally relevant exposure concentration. The shrimp concentrated LAS from seawater with a mean BCF value of 120 L kg(-1) after a 7-day exposure. Uptake biokinetics were best described by a saturation model, with an estimated BCFss, of 159 ± 34 L kg(-1), reached after 11.5 days. Shrimp weight influenced significantly BCF value with smaller individuals presenting higher affinity to LAS. To the light of a whole body autoradiography, major accumulation of LAS occurred in the cephalothorax circulatory system (gills, heart, hepatopancreas) and ocular peduncle, but not in the flesh, limiting potential transfer to human consumers. LAS depuration rate constant value of the shrimp was 1.18 ± 0.08 d(-1) leading to less than 1% of remaining LAS in its tissues after 8 days of depuration.

  17. Linear alkylbenzene sulfonate (LAS) in water of Lake Dianchi--spatial and seasonal variation, and kinetics of biodegradation.

    PubMed

    Wang, Zhi; Xiao, Bangding; Wu, Xingqiang; Tu, Xinhai; Wang, Yingcai; Sun, Xiaolei; Song, Lirong

    2010-12-01

    For the purpose of elucidating the environmental characteristics of anion surfactants [linear alkylbenzene sulfonates (LAS)] in the water of Lake Dianchi, a sampling investigation in the field from October 2006 to July 2007 and a batch of biodegradation experiments in the laboratory were carried out. The results showed that concentrations of LAS ranged from 18.6 to 260.1 μg L(-1), and the average concentration was 52.6 μg L(-1) in Lake Dianchi. The highest concentrations of LAS were found in the Northwest region, and the distribution of LAS varied through seasons, with much lower concentrations in fall than in any other seasons. LAS can be primarily biodegraded by microorganisms in the lake water, and the percentage of degradation was >97% after 28 days. Biodegradation of LAS was well-fitted with the kinetic model presented in this paper, and the half-lives ranged from 3.2 to 16.3 days. Temperature, pH, and initial concentrations could affect the biodegradation of LAS, among which temperature was the major factor influencing on biodegradation of LAS in water of Lake Dianchi.

  18. New sample treatment for determination of linear alkylbenzene sulfonate (LAS) in agricultural soils by liquid chromatography with fluorescence detection.

    PubMed

    Nimer, M; Ballesteros, O; Navalón, A; Crovetto, G; Verge, C; López, I; Berna, J L; Vílchez, J L

    2007-03-01

    A new sample-treatment procedure has been developed for determination of total linear alkylbenzene sulfonate (LAS), i.e. homologues and isomers, in agricultural soil. The procedure involves two steps, ultrasound-assisted extraction of LAS from the samples with methanol then clean-up of the methanolic extracts and preconcentration of the LAS by solid-phase extraction on two adsorbent cartridges (SAX and C18). The ultrasound-assisted procedure reduces extraction time (10 min in contrast with 6-12 h for conventional Soxhlet extraction) and requires only small volumes of organic solvent. The effect of different variables interacting in the ultrasound-assisted extraction process was studied. Finally, separation and quantification of the homologues and isomers of LAS was performed by liquid chromatography with fluorescence detection (LC-FD). 2-Octylbenzenesulfonic acid sodium salt (Na-2ØC8-LAS) was used as internal standard. The proposed method was satisfactorily used for determination of LAS in agricultural soil samples from the fertile plain of Granada (Spain).

  19. The degradation of linear alkylbenzene sulfonate (LAS) in the presence of light and natural biofilms: the important role of photosynthesis.

    PubMed

    Hua, Xiuyi; Li, Ming; Su, Yulong; Dong, Deming; Guo, Zhiyong; Liang, Dapeng

    2012-08-30

    Photosynthesis of algae usually changes the chemical conditions of microenvironment in natural waters. However, few studies have been carried out to examine the effects of diurnal variation and photosynthesis on behavior of organic pollutants in aquatic environments. In this study, linear alkylbenzene sulfonate (LAS) was selected as a representative of non-persistent organic pollutants to investigate the degradation of this type of pollutants in the presence of light and natural biofilms by laboratory batch experiments, with special emphasis on the effect of photosynthesis of the biofilms. The maximum decrease of LAS was observed in the coexistence of both illumination and fully active biofilms, and about 75% of the LAS were removed after a 36-h degradation experiment. The removal of LAS was found to be dominated by photosynthesis of the biofilms, with lesser roles attributed to biodegradation and adsorption by the biofilms, and the role of direct photolysis was negligible. The production of some reactive oxygen species might account for the role of photosynthesis in decomposing the LAS. The study confirms the important roles of algae biofilms and their photosynthesis in determining the fate of organic pollutants in aquatic environments.

  20. Wide-range and accurate modeling of linear alkylbenzene sulfonate (LAS) adsorption/desorption on agricultural soil.

    PubMed

    Oliver-Rodríguez, B; Zafra-Gómez, A; Reis, M S; Duarte, B P M; Verge, C; de Ferrer, J A; Pérez-Pascual, M; Vílchez, J L

    2015-11-01

    In this paper, rigorous data and adequate models about linear alkylbenzene sulfonate (LAS) adsorption/desorption on agricultural soil are presented, contributing with a substantial improvement over available adsorption works. The kinetics of the adsorption/desorption phenomenon and the adsorption/desorption equilibrium isotherms were determined through batch studies for total LAS amount and also for each homologue series: C10, C11, C12 and C13. The proposed multiple pseudo-first order kinetic model provides the best fit to the kinetic data, indicating the presence of two adsorption/desorption processes in the general phenomenon. Equilibrium adsorption and desorption data have been properly fitted by a model consisting of a Langmuir plus quadratic term, which provides a good integrated description of the experimental data over a wide range of concentrations. At low concentrations, the Langmuir term explains the adsorption of LAS on soil sites which are highly selective of the n-alkyl groups and cover a very small fraction of the soil surface area, whereas the quadratic term describes adsorption on the much larger part of the soil surface and on LAS retained at moderate to high concentrations. Since adsorption/desorption phenomenon plays a major role in the LAS behavior in soils, relevant conclusions can be drawn from the obtained results.

  1. Linear alkyl benzene sulphonate (LAS) degradation by immobilized Pseudomonas aeruginosa under low intensity ultrasound.

    PubMed

    Lijun, Xiang; Bochu, Wang; Zhimin, Li; Chuanren, Duan; Qinghong, Wang; Liu, Liu

    2005-01-15

    We studied the LAS degradation of immobilized Pseudomonas aeruginosa with low-intensity ultrasonic and the influence of original LAS concentration, pH, rotary velocity and different conditions of low-intensity ultrasonic irradiation on the degradation of LAS. In our experiment, the degradation rate of LAS was the main index. We found that low-intensity ultrasonic irradiation could improve the metabolism of microorganism cells and promote the LAS biodegradation of immobilized cells. In the experiment, 50 mg/l LAS were used to simulate wastewater, and low-intensity ultrasonic was considered. We found the influence was obvious, and the optimal degradation rate was acquired when the conditions of ultrasonic were frequency 24 kHz, power 8 W, stimulation time 5 s, intermissive time 30 s, and total time 10 min. The LAS degradation rate of immobilized cells with ultrasonic were respectively 40% and 9.5% higher than that of the suspending cells and immobilized cells without irradiation.

  2. Optimization of linear alkylbenzene sulfonate (LAS) degradation in UASB reactors by varying bioavailability of LAS, hydraulic retention time and specific organic load rate.

    PubMed

    Okada, Dagoberto Y; Delforno, Tiago P; Esteves, Andressa S; Sakamoto, Isabel K; Duarte, Iolanda C S; Varesche, Maria B A

    2013-01-01

    Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the bioavailability of LAS based on the concentration of biomass in the system (1.3-16 g TS/L), the hydraulic retention time (HRT), which was operated at 6, 35 or 80 h, and the concentration of co-substrates as specific organic loading rates (SOLR) ranging from 0.03-0.18 g COD/g TVS.d. The highest degradation rate of LAS (76%) was related to the lowest SOLR (0.03 g COD/g TVS.d). Variation of the HRT between 6 and 80 h resulted in degradation rates of LAS ranging from 18% to 55%. Variation in the bioavailability of LAS resulted in discrete changes in the degradation rates (ranging from 37-53%). According to the DGGE profiles, the archaeal communities exhibited greater changes than the bacterial communities, especially in biomass samples that were obtained from the phase separator. The parameters that exhibited more influence on LAS degradation were the SOLR followed by the HRT.

  3. Environmental levels of Linear alkylbenzene Sulfonates (LAS) in sediments from the Tagus estuary (Portugal): environmental implications.

    PubMed

    Hampel, M; Canário, J; Branco, V; Vale, C; Blasco, J

    2009-02-01

    Sediments from the Tagus estuary (Portugal) were collected at 40 stations in July and December 2004. Total LAS concentrations ranged between 0.03 and 17.76 mg LAS.kg(-1) dry weight in July, and between 0.09 and 9.57 mg LAS.kg(-1) in December. Highest LAS concentrations were found at the upper northern part of the estuary, coincident with the localisation of an important waste water treatment station. According to the Predicted No Effect Concentration (PNEC) of 8.1 mg.kg(-1) derived for this compound, Environmental Risk Assessment (ERA) identified a hazard for the ecosystem at the station with the highest LAS concentration, and similar results are obtained by Equilibrium Partitioning Method (EPM). Nevertheless, LAS concentrations decreased significantly between samplings in the stations with the highest LAS concentrations in July, whereas increased LAS concentrations at adjacent stations were found in December. In the remaining stations, LAS concentrations were up to three orders of magnitude lower, representing no hazard for the sediment community.

  4. Probabilistic risk assessment for linear alkylbenzene sulfonate (LAS) in sewage sludge used on agricultural soil.

    PubMed

    Schowanek, Diederik; David, Helen; Francaviglia, Rosa; Hall, Jeremy; Kirchmann, Holger; Krogh, Paul Henning; Schraepen, Nathalie; Smith, Stephen; Wildemann, Tanja

    2007-12-01

    Deterministic and probabilistic risk assessments were developed for commercial LAS in agricultural soil amended with sewage sludge. The procedure done according to ILSI Europe's Conceptual Framework [Schowanek, D., Carr, R., David, H., Douben, P., Hall, J., Kirchmann, H., Patria, L., Sequi, P., Smith, S., Webb, S.F., 2004. A risk-based methodology for deriving quality standards for organic contaminants in sewage sludge for use in agriculture-conceptual Framework. Regul. Toxicol. Pharmacol. 40 (3), 227-251], consists of three main steps. First, the most sensitive endpoint was determined. This was found to be the chronic ecotoxicity of LAS to soil invertebrates and plants. Additional endpoints, such as potential for plant uptake and transfer in the food chain, leaching to groundwater, surface erosion run-off, human health risk via drinking water, plant consumption and soil ingestion were also systematically evaluated but were all assessed to be of little toxicological significance. In the second step, a back-calculation was conducted from the Predicted No-Effect Concentration in soil (PNECsoil) to a safe level of LAS in sludge (here called 'Sludge Quality Standard'; SQS). The deterministic approach followed the default agricultural soil exposure scenario in the EU-Technical Guidance Document (TGD). The SQS for LAS was calculated as 49 g/kg sludge Dry Matter (DM). In order to assess the potential variability as a result of varying agricultural practices and local environmental conditions, two probabilistic exposure assessment scenarios were also developed. The mean SQS was estimated at 55 and 27.5 g/kg DM for the homogeneous soil mixing and soil injection scenarios, respectively. In the final step, the resulting SQS values were evaluated for consistency and relevance versus available information from agricultural experience and field tests. No build-up, adverse impact on soil fertility, agronomic performance, or animal/human health have been reported for agricultural

  5. Anionic surfactant linear alkylbenzene sulfonates (LAS) in sediments from the Gulf of Gdańsk (southern Baltic Sea, Poland) and its environmental implications.

    PubMed

    Hampel, Miriam; Mauffret, Aourell; Pazdro, Ksenia; Blasco, Julian

    2012-10-01

    Linear alkylbenzene sulfonate (LAS) is a group of anionic surfactants employed in the formulation of laundry and cleaning products, with a global production rate of 4 million metric tons. Sediments from the Polish coast of the southern Baltic Sea were collected at ten stations. Total LAS concentrations, measured by high-performance liquid chromatography, were between 0.04 and 0.72 mg LAS·kg(-1) dry weight. Highest LAS concentrations were found in suspended matter collected from the Vistula River, sediment collected close to the Vistula River mouth and from the Gdańsk Deep, known as the depositional area. With the obtained environmental LAS concentrations, a risk assessment for this surfactant has been carried out, based on publicly available acute and chronic toxicity data in target organisms. The results indicated that LAS could pose a low risk for the existing benthic community applying worst case scenario assessment. This is the first time that levels of LAS have been measured in environmental samples of the southern Baltic Sea.

  6. Anaerobic degradation of linear alkylbenzene sulfonate (LAS) in fluidized bed reactor by microbial consortia in different support materials.

    PubMed

    de Oliveira, Lorena Lima; Costa, Rachel Biancalana; Okada, Dagoberto Yukio; Vich, Daniele Vital; Duarte, Iolanda Cristina Silveira; Silva, Edson Luiz; Varesche, Maria Bernadete Amâncio

    2010-07-01

    Four anaerobic fluidized bed reactors filled with activated carbon (R1), expanded clay (R2), glass beads (R3) and sand (R4) were tested for anaerobic degradation of LAS. All reactors were inoculated with sludge from a UASB reactor treating swine wastewater and were fed with a synthetic substrate supplemented with approximately 20 mg l(-1) of LAS, on average. To 560 mg l(-1) COD influent, the maximum COD and LAS removal efficiencies were mean values of 97+/-2% and 99+/-2%, respectively, to all reactors demonstrating the potential applicability of this reactor configuration for treating LAS. The reactors were kept at 30 degrees C and operated with a hydraulic retention time (HRT) of 18h. The use of glass beads and sand appear attractive because they favor the development of biofilms capable of supporting LAS degradation. Subsequent 16S rRNA gene sequencing and phylogenetic analysis of samples from reactors R3 and R4 revealed that these reactors gave rise to broad microbial diversity, with microorganisms belonging to the phyla Bacteroidetes, Firmicutes, Actinobacteria and Proteobacteria, indicating the role of microbial consortia in degrading the surfactant LAS.

  7. 40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylbenzene sulfonate, amine salt... Substances § 721.1625 Alkylbenzene sulfonate, amine salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate,...

  8. 40 CFR 721.10035 - Alkylbenzene sulfonate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylbenzene sulfonate (generic). 721... Substances § 721.10035 Alkylbenzene sulfonate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate...

  9. 40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylbenzene sulfonate, amine salt... Substances § 721.1625 Alkylbenzene sulfonate, amine salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate,...

  10. 40 CFR 721.10035 - Alkylbenzene sulfonate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylbenzene sulfonate (generic). 721... Substances § 721.10035 Alkylbenzene sulfonate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate...

  11. Fate of linear alkylbenzene sulfonate in the Mississippi River

    USGS Publications Warehouse

    Tabor, C.F.; Barber, L.B.

    1996-01-01

    The 2 800-km reach of the Mississippi River between Minneapolis, MN, and New Orleans, LA, was examined for the occurrence and fate of linear alkylbenzene sulfonate (LAS), a common anionic surfactant found in municipal sewage effluents. River water and bottom sediment were sampled in the summer and fall of 1991 and in the spring of 1992. LAS was analyzed using solid- phase extraction/derivatization/gas chromatography/mass spectrometry. LAS was present on all bottom sediments at concentrations ranging from 0.01 to 20 mg/kg and was identified in 21% of the water samples at concentrations ranging from 0.1 to 28.2 ??g/L. The results indicate that LAS is a ubiquitous contaminant on Mississippi River bottom sediments and that dissolved LAS is present mainly downstream from the sewage outfalls of major cities. The removal of the higher LAS homologs and external isomers indicates that sorption and biodegradation are the principal processes affecting dissolved LAS. Sorbed LAS appears to degrade slowly.

  12. Asthmagenic properties of a newly developed detergent ingredient: sodium iso-nonanoyl oxybenzene sulphonate.

    PubMed Central

    Stenton, S C; Dennis, J H; Walters, E H; Hendrick, D J

    1990-01-01

    The suspicion that a newly developed detergent ingredient, sodium iso-nonanoyl oxybenzene sulphonate (SINOS), was inducing asthma among a workforce led to a series of inhalation challenge tests to determine the specificity and dose response characteristics of its asthma provoking properties. Three previously exposed workers, three non-exposed non-asthmatic controls, and three non-exposed asthmatic controls were challenged with SINOS 0.01-100 micrograms and another chemically similar surface active detergent ingredient, linear alkyl benzene sulphonate (LAS) 0.01-100 micrograms. Asthmatic symptoms, late falls in FEV1, and increases in non-specific bronchial responsiveness were seen after the inhalation of SINOS in all three workers, confirming SINOS as a cause of occupational asthma. No changes were seen after the inhalation of SINOS in either group of control subjects nor after LAS in any subject. These findings suggest that SINOS causes asthma through a specific hypersensitivity mechanism unrelated to its surface active properties. PMID:2165800

  13. Fungal metabolism of n-alkylbenzenes

    SciTech Connect

    Fedorak, P.M.; Westlake, D.W.S.

    1986-02-01

    Isolates of Paecilomyces, Verticillium, Beauveria, and Penicillium species were tested for ability to metabolize a variety of n-alkylbenzenes. Minimum side chain lengths were required for metabolism of these substrates. These were C/sub 4/ for the Paecilomyces sp., C/sub 8/ for the Verticillium sp., and C/sub 9/ for the other two isolates. Growth on dodecylbenzene yielded benzoic and phenylacetic acids as transient intermediates, and these acids supported growth of the isolates.

  14. 40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkylbenzene sulfonate, amine salt... Substances § 721.1625 Alkylbenzene sulfonate, amine salt. (a) Chemical substance and significant new uses... salt (PMN P-90-456) is subject to reporting under this section for the significant new use described...

  15. 40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkylbenzene sulfonate, amine salt... Substances § 721.1625 Alkylbenzene sulfonate, amine salt. (a) Chemical substance and significant new uses... salt (PMN P-90-456) is subject to reporting under this section for the significant new use described...

  16. DNA microarray mediated transcriptional profiling of Nitrosomonas europaea in response to linear alkylbenzene sulfonates.

    PubMed

    Urakawa, Hidetoshi; Matsumoto, Junpei; Inaba, Kazuho; Tsuneda, Satoshi

    2008-05-01

    Linear alkylbenzene sulfonates (LAS) constitute, quantitatively, the most important group of synthetic surfactants used today. We studied the gene expression of Nitrosomonas europaea in response to LAS using a DNA microarray because ammonia-oxidizers are thought to be more sensitive to LAS than other microorganisms. Our objective was to elucidate which genes are expressed for N. europaea in response to LAS exposure. Microarray analysis and real-time PCR assay revealed that c. 30 genes were significantly expressed after LAS exposure, in particular genes associated with energy production and conversion. Our findings demonstrate that physical disruption of membrane structures, which contain enzymes associated with energy production and conversion, might be an important explanation for the high sensitivity of N. europaea to LAS exposure.

  17. Mineralization of Linear Alkylbenzene Sulfonate by a Four-Member Aerobic Bacterial Consortium

    PubMed Central

    Jiménez, Luis; Breen, Alec; Thomas, Nikki; Federle, Thomas W.; Sayler, Gary S.

    1991-01-01

    A bacterial consortium capable of linear alkylbenzene sulfonate (LAS) mineralization under aerobic conditions was isolated from a chemostat inoculated with activated sludge. The consortium, designated KJB, consisted of four members, all of which were gram-negative, rod-shaped bacteria that grew in pairs and short chains. Three isolates had biochemical properties characteristic of Pseudomonas spp.; the fourth showed characteristics of the Aeromonas spp. Cell suspensions were grown together in minimal medium with [14C]LAS as the only carbon source. After 13 days of incubation, more than 25% of the [14C]LAS was mineralized to 14CO2 by the consortium. Pure bacterial cultures and combinations lacking any one member of the KJB bacterial consortium did not mineralize LAS. Three isolates carried out primary biodegradation of the surfactant, and one did not. This study shows that the four bacteria complemented each other and synergistically mineralized LAS, indicating catabolic cooperation among the four consortium members. PMID:16348496

  18. European risk assessment of LAS in agricultural soil revisited: species sensitivity distribution and risk estimates.

    PubMed

    Jensen, John; Smith, Stephen R; Krogh, Paul Henning; Versteeg, Donald J; Temara, Ali

    2007-10-01

    Linear alkylbenzene sulphonate (LAS) is used at a rate of approximately 430,000 tons/y in Western Europe, mainly in laundry detergents. It is present in sewage sludge (70-5,600 mg/kg; 5-95th percentile) because of its high usage per capita, its sorption and precipitation in primary settlers, and its lack of degradation in anaerobic digesters. Immediately after amendment, calculated and measured concentrations are <1 to 60 mg LAS/kg soil. LAS biodegrades rapidly in soil with primary and ultimate half-lives of up to 7 and 30 days, respectively. Calculated residual concentrations after the averaging time (30 days) are 0.24-18 mg LAS/kg soil. The long-term ecotoxicity to soil microbiota is relatively low (EC10 >or=26 mg sludge-associated LAS/kg soil). An extensive review of the invertebrate and plant ecotoxicological data, combined with a probabilistic assessment approach, led to a PNEC value of 35 mg LAS/kg soil, i.e. the 5th percentile (HC5) of the species sensitivity distribution (lognormal distribution of the EC10 and NOEC values). Risk ratios were identified to fall within a range of 0.01 (median LAS concentration in sludge) to 0.1 (95th percentile) and always below 0.5 (maximum LAS concentration measured in sludge) according to various scenarios covering different factors such as local sewage influent concentration, water hardness, and sewage sludge stabilisation process. Based on the present information, it can be concluded that LAS does not represent an ecological risk in Western Europe when applied via normal sludge amendment to agricultural soil.

  19. A new method for the routine analysis of LAS and PAH in sewage sludge by simultaneous sonication-assisted extraction prior to liquid chromatographic determination.

    PubMed

    Santos, J L; Aparicio, I; Alonso, E

    2007-12-12

    Linear alkylbenzene sulphonates (LAS) and polycyclic aromatics hydrocarbons (PAH) are organic pollutants in sewage sludge which will have to be monitored in the European Union according to the third draft of a future sludge directive. In the present work, an analytical method for the simultaneous extraction of 4 LAS homologues and 16 PAH congeners in sludge from wastewater treatment plants is proposed to improve the routine analysis of these compounds in sludge samples. The method involves sonication assisted extraction, clean-up and preconcentration by solid phase extraction, and determination by high-performance liquid chromatography with ultraviolet diode array (UV-DAD) and fluorescence (FLD) detectors. Average recoveries were 87% for LAS and 76% for PAH, with relative standard deviations below 13%. Limits of quantification of LAS and PAH were in the range from 13 to 56 mg kg(-1) and from 80 to 650 microg kg(-1), respectively, when using UV-DAD. Limits of quantification of LAS and PAH were in the range 5-18 mg kg(-1) and from 1 to 150 microg kg(-1), respectively, when using FLD. The applicability of the proposed method was evaluated by the determination of these compounds in sludge from wastewater treatment plants in Seville (South Spain).

  20. Atomistic simulation study of linear alkylbenzene sulfonates at the water/air interface

    PubMed Central

    He, Xibing; Guvench, Olgun; MacKerell, Alexander D.; Klein, Michael L.

    2010-01-01

    Molecular Dynamics simulations with the CHARMM atomistic force field have been used to study monolayers of a series of linear alkylbenzene sulfonates (LAS) at the water/air interface. Both the numbers of carbon atoms in the LAS alkyl tail (1 to 11), and the position of attachment of the benzene ring on the alkyl chain have been varied. Totally 36 LAS homologues and isomers have been investigated. The surface tensions of the systems and the average tilt angles of the LAS molecules are found to be related to both the length and the degree of branching of the alkyl tails, whereas the solubility and mobility are mostly determined by the tail length. PMID:20614916

  1. Pyrolysis products of linear alkylbenzenes--implications in fire debris analysis.

    PubMed

    Contreras, Patricia A; Houck, Stephen S; Davis, William M; Yu, Jorn C-C

    2013-01-01

    In this case report, potential interferences from an improvised fire-extinguishing agent, a dishwashing liquid, containing linear alkylbenzene sulfonates (LAS), was studied. The presence of linear alkylbenzenes (LABs) in the fire debris sample was identified from the summed ion profile (SIP) analysis. It was found that the LAS from dishwashing liquids produce LABs by thermal degradation. Direct pyrolysis of a LAS-containing dishwashing liquid at 300°C yielded a distribution of LABs in the SIP. LABs began to break down at pyrolysis temperatures between 450 and 500°C and completely break down by 800°C. Observed pyrolysis breakdown products of LABs included toluene, ethylbenzene, meta-, para-, and ortho-xylenes, propylbenzene, indane, naphthalene, and 1- and 2-methylnaphthalenes. These data suggested the presence of LABs in fire debris evidence might complicate subsequent analysis because their breakdown products contained some of the target compounds common to ignitable liquid identification. Therefore, a positive determination of the presence of foreign ignitable liquids should be carefully evaluated when there is a presence of LABs in the SIP.

  2. Ozone degradation of alkylbenzene sulfonate in aqueous solutions using a stirred tank reactor with recirculation.

    PubMed

    Jurado-Alameda, Encarnación; Vicaria, José M; Altmajer-Vaz, Deisi; Luzón, Germán; Jiménez-Pérez, José L; Moya-Ramírez, Ignacio

    2012-01-01

    The degradation of linear alkylbenzene sulfonates (LAS) in aqueous solutions by ozone has been investigated. The ozonation process was performed in a stirred tank reactor with recirculation which simulates the clean-in-place process used in many industrial facilities. The gas-liquid mass transfer of ozone in a buffer solution at different temperatures (25-55°C) was also studied in the same device, revealing that ozone decomposition can be considered negligible under the experimental conditions assayed. The effect of the initial LAS concentration, temperature, and ozone concentration on the concentration of homologues and total LAS were analysed as a function of time. Both concentrations diminished with time, this effect being more significant when higher temperatures were assayed. The relative proportion of homologues shows that the homologues of higher chain length are degraded in a greater proportion than are the homologues with shorter chain lengths.

  3. INHIBITION OF ALKYLBENZENE BIODEGRADATION UNDER DENITRIFYING CONDITIONS BY USING THE ACETYLENE BLOCK TECHNIQUE

    EPA Science Inventory

    Addition of acetylene to microcosms simultaneously amended with nitrate and alkylbenzenes resulted in inhibition of the rate of alkylbenzene biodegradation under denitrifying conditions. Toluene, xylenes, and 1,2,4-trimethylbenzene were recalcitrant, whereas ethylbenzene was degr...

  4. 40 CFR 721.10487 - Alkylbenzenes sulfonic acids, metal salts (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkylbenzenes sulfonic acids, metal... Specific Chemical Substances § 721.10487 Alkylbenzenes sulfonic acids, metal salts (generic). (a) Chemical... as alkylbenzenes sulfonic acids, metal salts (PMNs P-04-599, P-04-600, P-04-605, and P-04-606)...

  5. 40 CFR 721.10487 - Alkylbenzenes sulfonic acids, metal salts (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkylbenzenes sulfonic acids, metal... Specific Chemical Substances § 721.10487 Alkylbenzenes sulfonic acids, metal salts (generic). (a) Chemical... as alkylbenzenes sulfonic acids, metal salts (PMNs P-04-599, P-04-600, P-04-605, and P-04-606)...

  6. Comparative kinetics study of the evolution of freshwater aquatic toxicity and biodegradability of linear and branched alkylbenzene sulfonates

    SciTech Connect

    Gard-Terech, A.; Palla, J.C.

    1986-10-01

    Evolution of both primary biodegradability and acute toxicity to daphnia and zebra fish of a linear alkylbenzene sodium sulfonate (LAS) and a branched alkylbenzene sodium sulfonate (BAS) have been measured simultaneously. In six of eight experiments, LAS was biodegraded to 90% in 7 days and BAS to 70% in 7 days. In the two other experiments, both LAS and BAS have shown the same biodegradation speed and reached the same biodegradation level in 7 days: 45% in one experiment and 55% in the other. The composition of bacteria population and the level of cellular ATP of the inoculum play a decisive role in the biodegradation. These results confirm that it is essential to know the composition of bacteria population present in the inoculum as well as their biochemical characteristics to accurately interpret results of biodegradation tests. In the case of a rapid primary biodegradation of LAS and BAS, the acute toxicity of LAS remains three times as high as that of BAS for at least 24 hr toward daphnia and 48 hr toward zebra fish. Their acute toxicity to daphnia and zebra fish become equivalent only after 72 hr. When primary biodegradation of both products is slower, the acute toxicity of LAS remains higher than that of BAS for more than 7 days.

  7. Influence of volatile fatty acid concentration stability on anaerobic degradation of linear alkylbenzene sulfonate.

    PubMed

    Okada, Dagoberto Y; Delforno, Tiago P; Esteves, Andressa S; Polizel, Juliana; Hirasawa, Julia S; Duarte, Iolanda C S; Varesche, Maria B A

    2013-10-15

    Linear alkylbenzene sulfonate (LAS) is an anionic surfactant used in cleaning products, which is usually found in wastewaters. Despite the greater LAS removal rate related to a lower concentrations of volatile fatty acids (VFA), the influence of different ranges of VFA on LAS degradation is not known. LAS degradation was evaluated in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors at different ranges of VFA concentrations. The reactors were fed with a synthetic wastewater containing LAS (14 mg/L). A greater LAS removal rate (40-80%) was related to the lower and narrower range of acetic acid concentration (1-22 mg/L) in the EGSB reactor. In the UASB reactor, the acetic acid concentrations presented a wider range (2-45 mg/L), and some low LAS removal rates (around 20-25%) were observed even at low acetic acid concentrations (<10 mg/L). The high recirculation rate in the EGSB reactor improved substrate-biomass contact, which resulted in a narrower range of VFA and greater LAS removal rate.

  8. Microbial characterization and degradation of linear alkylbenzene sulfonate in an anaerobic reactor treating wastewater containing soap powder.

    PubMed

    Carosia, Mariana Fronja; Okada, Dagoberto Yukio; Sakamoto, Isabel Kimiko; Silva, Edson Luiz; Varesche, Maria Bernadete Amâncio

    2014-09-01

    The aim of this study was to evaluate the removal of linear alkylbenzene sulfonate (LAS) in an anaerobic fluidized bed reactor (AFBR) treating wastewater containing soap powder as LAS source. At Stage I, the AFBR was fed with a synthetic substrate containing yeast extract and ethanol as carbon sources, and without LAS; at Stage II, soap powder was added to this synthetic substrate obtaining an LAS concentration of 14 ± 3 mg L(-1). The compounds of soap powder probably inhibited some groups of microorganisms, increasing the concentration of volatile fatty acids (VFA) from 91 to 143 mg HAc L(-1). Consequently, the LAS removal rate was 48 ± 10% after the 156 days of operation. By sequencing, 16S rRNA clones belonging to the phyla Proteobacteria and Synergistetes were identified in the samples taken at the end of the experiment, with a remarkable presence of Dechloromonas sp. and Geobacter sp.

  9. Influence of soil moisture on linear alkylbenzene sulfonate-induced toxicity in ammonia-oxidizing bacteria.

    PubMed

    Nielsen, Klaus B; Brandt, Kristian K; Jacobsen, Anne-Marie; Mortensen, Gerda K; Sørensen, Jan

    2004-02-01

    Moisture affects bioavailability and fate of pollutants in soil, but very little is known about moisture-induced effects on pollutant toxicity. We here report on a modifying effect of moisture on degradation of linear alkylbenzene sulfonates (LASs) and on their toxicity towards ammonia-oxidizing bacteria (AOB) in agricultural soil. In soil spiked with two LAS levels (250 or 1,000 mg/kg) and incubated at four different moisture levels (9-100% of water-holding capacity), degradation was strongly affected by both soil moisture and initial LAS concentration, resulting in degradation half-lives ranging from 13 to more than 160 d. Toxicity towards AOB assessed by a novel Nitrosomonas europaea luxAB-reporter assay was correlated to total LAS concentration, indicating that LAS remained bioavailable over time without accumulation of toxic intermediates. Toxicity towards indigenous AOB increased with increasing soil moisture. The results indicate that dry soil conditions inhibit LAS degradation and provide protection against toxicity within the indigenous AOB, thus allowing for a rapid recovery of this population when LAS degradation is resumed and completed after rewetting. We propose that the protection of microbial populations against toxicity in dry soil may be a general phenomenon caused primarily by limited diffusion and thus a low bioavailability of the toxicant.

  10. Evaluation of a laboratory-generated NOEC for linear alkylbenzene sulfonate in outdoor experimental streams

    SciTech Connect

    Fairchild, J.F.; Dwyer, F.J.; Point, T.W. la; Burch, S.A.; Ingersoll, C.G. . National Fisheries Contaminant Research Center)

    1993-10-01

    Laboratory and field studies were conducted with linear alkylbenzene sulfonate (LAS) to evaluate the use of the laboratory-generated NOECs for protecting aquatic organisms in outdoor experimental streams. Fathead minnows (Pimephales promelas) and freshwater amphipods (Hyalella azteca) were exposed in the laboratory to an environmentally realistic mixture of LAS for 7 d; fathead minnows were also exposed in a 28-d study. Calculated NOEC values based on survival and growth ranged from 0.3 to 0.9 mg/L for fathead minnows and from 0.6 to 1.4 mg/L for amphipods. Toxicity of LAS in 4-, 7-, and 28-d exposured of fathead minnows was similar because mortality occurred within the initial 24 h of exposure; mortality was more sensitive than growth as a chronic end point. The addition of 5% sewage effluent to well and stream water had little effect on the bioavailability of LAS; however, total organic carbon levels were low in all treatments. A 45-d exposure of three outdoor experimental streams to 0.36 mg/L LAS had no effects on survival of fathead minnows or amphipods, dynamics of benthic invertebrates, growth of periphyton, or processing of detrital leaves. Results indicated that the laboratory-generated NOEC for LAS was protective of experimental stream communities under the studied conditions.

  11. 40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.1625 Alkylbenzene sulfonate, amine salt. Link to an amendment published at 79 FR 34636, June 18, 2014. (a) Chemical substance and significant new uses subject to reporting. (1) The...

  12. Effect of linear alkylbenzene sulfonates on the growth of aerobic heterotrophic cultivable bacteria isolated from an agricultural soil.

    PubMed

    Sánchez-Peinado, María del Mar; González-López, Jesús; Rodelas, Belén; Galera, Vanesa; Pozo, Clementina; Martínez-Toledo, María Victoria

    2008-08-01

    An enrichment culture technique was used to isolate soil bacteria capable of growing in the presence of two different concentrations of linear alkylbenzene sulfonates (LAS) (10 and 500 microg ml(-1)). Nine bacterial strains, representatives of the major colony types of aerobic heterotrophic cultivable bacteria in the enriched samples, were isolated and subsequently identified by PCR-amplification and partial sequencing of the 16S rRNA gene. Amongst the isolates, strains LAS05 (Pseudomonas syringae), LAS06 (Staphylococcus epidermidis), LAS07 (Delftia tsuruhatensis), LAS08 (Staphylococcus epidermidis) and LAS09 (Enterobacter aerogenes), were able to grow in pure culture in dialysed soil media amended with LAS (50 microg ml(-1)). The three Gram-negative strains grew to higher cell numbers in the presence of 50 microg ml(-1) of LAS, compared to LAS-unamended dialysed soil medium, and were selected for further testing of their ability to use LAS as carbon source. However, HPLC analysis of culture supernatants showed that the three strains can tolerate but not degrade LAS when grown in pure cultures. A higher concentration of soluble phosphates was recorded in dialysed soil media amended with LAS (50 microg ml(-1)) compared to unamended control media, suggesting an effect of the surfactant that enhanced the bioavailability of P from soil. The presence of LAS at a concentration of 50 microg ml(-1) had an important impact on growth of selected aerobic heterotrophic soil bacteria, a deleterious effect which may be relevant for the normal function and evolution of agricultural soil.

  13. Environmental monitoring study of linear alkylbenzene sulfonates and insoluble soap in Spanish sewage sludge samples.

    PubMed

    Cantarero, Samuel; Zafra-Gómez, Alberto; Ballesteros, Oscar; Navalón, Alberto; Reis, Marco S; Saraiva, Pedro M; Vílchez, José L

    2011-01-01

    In this work we present a monitoring study of linear alkylbenzene sulfonates (LAS) and insoluble soap performed on Spanish sewage sludge samples. This work focuses on finding statistical relations between LAS concentrations and insoluble soap in sewage sludge samples and variables related to wastewater treatment plants such as water hardness, population and treatment type. It is worth to mention that 38 samples, collected from different Spanish regions, were studied. The statistical tool we used was Principal Component Analysis (PC), in order to reduce the number of response variables. The analysis of variance (ANOVA) test and a non-parametric test such as the Kruskal-Wallis test were also studied through the estimation of the p-value (probability of obtaining a test statistic at least as extreme as the one that was actually observed, assuming that the null hypothesis is true) in order to study possible relations between the concentration of both analytes and the rest of variables. We also compared LAS and insoluble soap behaviors. In addition, the results obtained for LAS (mean value) were compared with the limit value proposed by the future Directive entitled "Working Document on Sludge". According to the results, the mean obtained for soap and LAS was 26.49 g kg(-1) and 6.15 g kg(-1) respectively. It is worth noting that LAS mean was significantly higher than the limit value (2.6 g kg(-1)). In addition, LAS and soap concentrations depend largely on water hardness. However, only LAS concentration depends on treatment type.

  14. Highly effective degradation of sodium dodecylbenzene sulphonate and synthetic greywater by Fenton-like reaction over zerovalent iron-based catalyst.

    PubMed

    Zhu, Shi-Ni; Wang, Chao; Yip, Alex C K; Tsang, Daniel C W

    2015-01-01

    There is an increasing interest to recycle greywater for meeting non-portable water demand. However, linear alkylbenzene sulphonates (a form of anionic surfactants) that are commonly found in greywater are less biodegradable at moderate to high concentrations. A fenton-like system is a relatively economic advanced oxidation process that can potentially be used for surfactant degradation in greywater treatment. This study investigated the feasibility of zerovalent iron (ZVI)-mediated Fenton's oxidation of sodium dodecylbenzene sulphonate (SDBS) using Fe0/H2O2 and Fe2+/Fe0/H2O2 systems under a range of operating conditions. For the Fe0/H2O2 binary system, the initial pH value and Fe0 dosage played important roles in final degradation efficiency. For the Fe2+/Fe0/H2O2 ternary systems, a small amount of Fe2+ (0.5-1.7 mM) contributed a synergistic effect to promote iron recycling and SDBS degradation. Approximately, 90% of SDBS mineralization efficiency was accomplished within 15 min at a pH range from 3.0 to 6.5, using 18 mM Fe0 and 15 mM H2O2. However, the removal kinetics was rate-limited by Fe2+ dissolution from the ZVI surfaces. The Fenton-like process of the Fe2+/Fe0/H2O2 ternary system also presents a promising treatment method for synthetic greywater, in which 90% TOC removal was achieved within the first 10 min; 78% COD and 91% BOD5 were achieved after 120 min of reaction.

  15. Paramaterization of a coarse-grained model for linear alkylbenzene sulfonate surfactants and molecular dynamics studies of their self-assembly in aqueous solution

    NASA Astrophysics Data System (ADS)

    He, Xibing; Shinoda, Wataru; DeVane, Russell; Anderson, Kelly L.; Klein, Michael L.

    2010-02-01

    A coarse-grained (CG) forcefield for linear alkylbenzene sulfonates (LAS) was systematically parameterized. Thermodynamic data from experiments and structural data obtained from all-atom molecular dynamics were used as targets to parameterize CG potentials for the bonded and non-bonded interactions. The added computational efficiency permits one to employ computer simulation to probe the self-assembly of LAS aqueous solutions into different morphologies starting from a random configuration. The present CG model is shown to accurately reproduce the phase behavior of solutions of pure isomers of sodium dodecylbenzene sulfonate, despite the fact that phase behavior was not directly taken into account in the forcefield parameterization.

  16. Bioremediation of surface water co-contaminated with zinc (II) and linear alkylbenzene sulfonates by Spirulina platensis

    NASA Astrophysics Data System (ADS)

    Meng, Huijuan; Xia, Yunfeng; Chen, Hong

    Potential remediation of surface water contaminated with linear alkylbenzene sulfonates (LAS) and zinc (Zn (II)) by sorption on Spirulina platensis was studied using batch techniques. Results show that LAS can be biodegraded by Spirulina platensis, and its biodegradation rate after 5 days was 87%, 80%, and 70.5% when its initial concentration was 0.5, 1, and 2 mg/L, respectively. The maximum Zn (II) uptake capacity of Spirulina platensis was found to be 30.96 mg/g. LAS may enhance the maximum Zn (II) uptake capacity of Spirulina platensis, which can be attributed to an increase in bioavailability due to the presence of LAS. The biodegradation rates of LAS by Spirulina platensis increased with Zn (II) and reached the maximum when Zn (II) was 4 mg/L. The joint toxicity test showed that the combined effect of LAS and Zn (II) was Synergistic. LAS can enhance the biosorption of Zn (II), and reciprocally, Zn (II) can enhance LAS biodegradation.

  17. Rayleigh scattering of linear alkylbenzene in large liquid scintillator detectors.

    PubMed

    Zhou, Xiang; Liu, Qian; Wurm, Michael; Zhang, Qingmin; Ding, Yayun; Zhang, Zhenyu; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-07-01

    Rayleigh scattering poses an intrinsic limit for the transparency of organic liquid scintillators. This work focuses on the Rayleigh scattering length of linear alkylbenzene (LAB), which will be used as the solvent of the liquid scintillator in the central detector of the Jiangmen Underground Neutrino Observatory. We investigate the anisotropy of the Rayleigh scattering in LAB, showing that the resulting Rayleigh scattering length will be significantly shorter than reported before. Given the same overall light attenuation, this will result in a more efficient transmission of photons through the scintillator, increasing the amount of light collected by the photosensors and thereby the energy resolution of the detector.

  18. Rayleigh scattering of linear alkylbenzene in large liquid scintillator detectors

    SciTech Connect

    Zhou, Xiang Zhang, Zhenyu; Liu, Qian; Zheng, Yangheng; Wurm, Michael; Zhang, Qingmin; Ding, Yayun; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-07-15

    Rayleigh scattering poses an intrinsic limit for the transparency of organic liquid scintillators. This work focuses on the Rayleigh scattering length of linear alkylbenzene (LAB), which will be used as the solvent of the liquid scintillator in the central detector of the Jiangmen Underground Neutrino Observatory. We investigate the anisotropy of the Rayleigh scattering in LAB, showing that the resulting Rayleigh scattering length will be significantly shorter than reported before. Given the same overall light attenuation, this will result in a more efficient transmission of photons through the scintillator, increasing the amount of light collected by the photosensors and thereby the energy resolution of the detector.

  19. Engineered lymphocytes to treat dinitrobenzene sulphonic acid colitis in mice.

    PubMed

    Felley, Christian; Michetti, Pierre

    2003-12-01

    Current treatments of inflammatory bowel diseases are limited either by their lack of efficacy or their potential toxicity. In recent years, major advances have been obtained by the development of biological therapies. However, these types of treatment are systemic and can lead to serious adverse events. The new venue of local biological treatments would be most welcome. In this issue of the Journal, Castagliuolo et al. show that lymphocytes engineered to produce TGF-beta1 can reverse dinitrobenzene sulphonic acid-induced colitis in mice. These engineered lymphocytes selectively accumulate in the intestinal mucosa due to the homing properties of their alpha4beta7 integrins, a ligand for MAdCAM1. A local treatment restricted to the inflamed mucosa can thus be obtained. This opens a brand new area of research with the hope of restoring the immunoregulatory balance selectively in the inflamed tissues.

  20. Occurrence, fate and environmental risk of linear alkylbenzene sulfonate in the Langat and Selangor River basins, Malaysia.

    PubMed

    Sakai, Nobumitsu; Shirasaka, Junichi; Matsui, Yasuto; Ramli, Mohd Redzuan; Yoshida, Kousuke; Ali Mohd, Mustafa; Yoneda, Minoru

    2017-04-01

    Five homologs (C10-C14) of linear alkylbenzene sulfonate (LAS) were quantitated in surface water collected in the Langat and Selangor River basins using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A geographic information system (GIS) was used to spatially analyze the occurrence of LAS in both river basins, and the LAS contamination associated with the population was elucidated by spatial analysis at a sub-basin level. The LAS concentrations in the dissolved phase (<0.45 μm) and 4 fractions separated by particle size (<0.1 μm, 0.1-1 μm, 1-11 μm and >11 μm) were analyzed to elucidate the environmental fate of LAS in the study area. The environmental risks of the observed LAS concentration were assessed based on predicted no effect concentration (PNEC) normalized by a quantitative structure-activity relationship model. The LAS contamination mainly occurred from a few populated sub-basins, and it was correlated with the population density and ammonia nitrogen. The dissolved phase was less than 20% in high contamination sites (>1000 μg/L), whereas it was more than 60% in less contaminated sites (<100 μg/L). The environmental fate of LAS in the study area was primarily subject to the adsorption to suspended solids rather than biodegradation because the LAS homologs, particularly in longer alkyl chain lengths, were considerably absorbed to the large size fraction (>11 μm) that settled in a few hours. The observed LAS concentrations exceeded the normalized PNEC at 3 sites, and environmental risk areas and susceptible areas to the LAS contamination were spatially identified based on their catchment areas.

  1. Screening method for linear alkylbenzene sulfonates in sediments based on water Soxhlet extraction assisted by focused microwaves with on-line preconcentration/derivatization/detection.

    PubMed

    Morales-Muñoz, S; Luque-García, J L; de Castro, Luque

    2004-02-13

    A screening method for linear alkylbenzene sulfonates (LAS) in sediments has been developed. Soxhlet extraction with water assisted by focused microwaves provides recoveries better (>90%) than obtained by conventional Soxhlet extraction (70-80%). Coupling of the extractor with an on-line preconcentration/derivatization/detection manifold through a flow injection (FI) interface allows a fully automated screening approach. A yes/no answer can be obtained in less than 2 h (for the whole analytical process), a short time compared with the at least 24 h of Soxhlet extraction (without final detection). Due to the use of water as leaching agent, the proposed method is environmentally friendly.

  2. Asymmetric energy flow in liquid alkylbenzenes: A computational study

    SciTech Connect

    Leitner, David M.; Pandey, Hari Datt

    2015-10-14

    Ultrafast IR-Raman experiments on substituted benzenes [B. C. Pein et al., J. Phys. Chem. B 117, 10898–10904 (2013)] reveal that energy can flow more efficiently in one direction along a molecule than in others. We carry out a computational study of energy flow in the three alkyl benzenes, toluene, isopropylbenzene, and t-butylbenzene, studied in these experiments, and find an asymmetry in the flow of vibrational energy between the two chemical groups of the molecule due to quantum mechanical vibrational relaxation bottlenecks, which give rise to a preferred direction of energy flow. We compare energy flow computed for all modes of the three alkylbenzenes over the relaxation time into the liquid with energy flow through the subset of modes monitored in the time-resolved Raman experiments and find qualitatively similar results when using the subset compared to all the modes.

  3. Enzymic oxidation of some alkylbenzenes in insects and vertebrates.

    PubMed

    Chakroborty, J; Smith, J N

    1967-02-01

    1. Oxidation rates of alkylbenzenes have been measured in 10000g supernatants of vertebrate livers, locust fat bodies and housefly abdomens. 2. Activity per g. of insect was greater in fly than locust preparations but both were of the same order as a range of vertebrate species. 3. Methyl groups of toluene and p-nitrotoluene were oxidized more rapidly than the side chains of higher homologues. 4. In the higher homologues hydroxylation occurred most readily at the alpha-methylene group and less readily at penultimate methylene and terminal methyl groups. 5. Oxidations in both vertebrates and insects were inhibited by piperonylbutoxide and similar synergists. 6. Oxidation activity was stimulated by pretreatment of rats, but not locusts, with phenobarbitone or 3,4-benzopyrene.

  4. Phase diagrams of low-density polyethylene-alkylbenzene systems

    NASA Astrophysics Data System (ADS)

    Ilyasova, A. N.; Kudryavtsev, Y. V.; Lebedeva, T. N.; Levashova, I. V.; Flyagina, Yu. A.; Pochivalov, K. V.

    2017-03-01

    Complete phase diagrams for mixtures of low-density polyethylene with p- and m-xylene are plotted by optical means in developing the concept of which partially crystalline polymers are microstructured liquids. It is shown that in contrast to the ones presented in the literature, both diagrams contain the solubility boundary curve of the low-molecular weight component in the polymer, above which the polyethylene has the structure of a single-phase gel (crosslinks formed by crystallites and amorphous regions saturated with xylene). At the figurative point on the diagrams, a situation is observed in which the dissolution of all the liquid contained in the initial two-phase system in the polymer is accompanied by its simultaneous complete amorphization. The parameters of the figurative point allow us to estimate the thermodynamic affinity of different alkylbenzenes toward polyethylene.

  5. Effects of linear alkylbenzene sulfonate on the sorption of Brij 30 and Brij 35 onto aquifer sand.

    PubMed

    Tripathi, Shweta; Brown, Derick G

    2008-03-01

    Surfactant sorption is of considerable importance to environmental applications, including surfactant flushing to mobilize hydrophobic contaminants; effects of surfactants on the transport of dissolved contaminants, microorganisms, and colloids through porous media; and bioremediation of hydrophobic organic compounds, as well as understanding the fate and transport of surfactants as environmental contaminants themselves. Although most sorption studies consider pure surfactants, commercial detergent formulations typically consist of mixtures of nonionic and anionic surfactants. In this study, the effects of varying concentrations of the anionic surfactant linear alkylbenzene sulfonate (LAS) on micelle formation and sorption behavior of the two commonly used nonionic surfactants Brij 30 and Brij 35 onto aquifer sand were examined. A strong linear relationship was observed between the critical micelle concentration (CMC) of the Brij surfactants and the concentration of LAS in the mixture, with the CMC decreasing with increasing concentration of LAS. The relative change in CMC as a function of the LAS concentration was identical forthe two Brij surfactants, indicating that LAS interacted with their common alkyl chains. Sorption isotherms were developed for Brij 30 and Brij 35 present as single surfactants in an aqueous solution as well as when present with LAS. Although LAS had minor effects on the maximum sorption plateaus of the Brij surfactants, Brij sorption at was significantly enhanced as a function of the LAS concentration for Brij aqueous concentrations below the CMC. Application of a multi-interaction isotherm model indicated that the formation of surface aggregates (e.g., hemimicelles) decreased with increasing LAS concentration. Overall, these results provide insight into the complex sorption behavior of surfactant mixtures.

  6. Pharmocokinetical study of Al- and Zn-sulphonated phthalocyanines

    NASA Astrophysics Data System (ADS)

    Kazachkina, Natalia I.; Zharkova, Natalia N.; Fomina, Galina I.; Yakubovskaya, Raisa I.; Sokolov, Victor V.; Lukyanets, Eugeny A.

    1996-12-01

    The comparative pharmacokinetical study of Al- and Zn- sulphonated phthalocyanines (AlPcS and ZnPcS, respectively) is the aim of the present work. Mice bearing solid Ehrlich tumor were used in this study. AlPcS (sodium salt) and ZnPcS (ammonium and sodium salts were used as photosensitizers. The photosensitizers were injected i/v in various doses. The exogenous fluorescence of tissues (tumor, liver, spleen, kidneys, muscles, skin) was measured dynamically after sensitization. It was shown that all of the photosensitizers under study had similar distribution pattern in organisms of mice and were selectively accumulated in the Ehrlich tumor tissue. The exogenous fluorescence intensity of tissues and it tumor:normal muscle ratio (Cs) depended on the dosage of the preparation, on the time, which had passed after drug injection, and on the stage of tumor growth. It was also shown that the kinetics of the tissue uptake of the studied sensitizers varied to some extent. Thus, the obtained data may be interesting for deeper understanding of the interaction of the dye with malignant tissues.

  7. Perfluorooctane sulphonate and perfluorooctanoic acid in drinking and environmental waters.

    PubMed

    Rumsby, Paul C; McLaughlin, Clare L; Hall, Tom

    2009-10-13

    Perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) are chemicals that have been used for many years as surfactants in a variety of industrial and consumer products. Owing to their persistent, bioaccumulative and toxic (PBT) characteristics, PFOS has been phased out by its principal producer and the use of PFOA has been reduced. This PBT potential and a number of pollution incidents have led in recent years to an increase in studies surveying the concentrations of PFOS and PFOA in environmental waters worldwide. This paper reviews the results of these studies, as well as the monitoring that was conducted after the pollution incidents. The results of surveys suggest that PFOS and PFOA are found in environmental waters worldwide at low levels. In general, these levels are below health-based values set by international authoritative bodies for drinking water. There have been limited measurements of these chemicals in drinking water, but again these are below health-based values, except in some cases following pollution incidents. Monitoring studies suggested that where PFOS and PFOA were detected, they were at similar levels in both source and drinking water, suggesting that drinking water treatment does not remove these chemicals. However, new data show that PFOS and PFOA are effectively removed by granular activated carbon absorbers in practice. Further research is required on the newer perfluorinated chemicals that appear to be safer, but their degradation products have not as yet been fully studied.

  8. Assessment of the hemolysis and endothelial cell cytotoxicity induced by residual linear alkylbenzene sulfonates on pharmaceutical rubber stoppers based on HPLC-ESI-MS.

    PubMed

    Li, Xianghui; Qiu, Lu; Li, Yueyue; Chen, Xiaofei; Zhu, Zhenyu; Chai, Yifeng

    2015-09-01

    This study was designed to develop a high-performance liquid chromatographic-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method for quantitative determination of residual surfactant linear alkylbenzene sulfonate (LAS) compounds on pharmaceutical rubber stoppers. An HPLC-ESI-MS method was developed for separation and determination of five LAS homologs (C10-C14) under gradient conditions using methanol and ammonium acetate as mobile phases. Hemolysis activity of residual LAS compounds was analyzed by spectrophotometry. Expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in human umbilical vein endothelial cells (HUVECs) after LAS compound treatment was examined by enzyme-linked sorbent assay. LAS compounds were well separated and determined by the established gradient conditions. The linear range was 0.05-8 µg/mL with correlation coefficients ≥0.997. Recoveries were from 73 to 134% and the relative standard deviation was <13.7%. There was a correlation between hemolysis rate and LAS compounds concentration when it was ≥0.8 µg/cm(2). LAS compounds decreased the viability of HUVECs and promoted the production of IL-6 and TNF-α. The developed analytical method was successful for quantitative determination of residual LAS compounds on pharmaceutical rubber stoppers and it is important to monitor and control the amount of LAS compounds on rubber stoppers.

  9. Guanidinoethyl sulphonate is a glycine receptor antagonist in striatum.

    PubMed

    Sergeeva, Olga A; Chepkova, Aisa N; Haas, Helmut L

    2002-11-01

    1. Guanidinoethyl sulphonate (GES) is an analogue of taurine and an inhibitor of taurine transport. Interactions of GES with GABA(A) and glycine receptors are studied by whole cell recording and fast drug application in isolated striatal neurons of the mouse. 2. We confirm that GES is a weak agonist at GABA(A) receptors, and is able to antagonize GABA-evoked responses. GES did not gate GlyR. 3. GES antagonized glycine responses in a concentration-dependent and surmountable manner. Glycine dose-response curves were shifted to the right by GES (0.5 mM), yielding EC(50)s and Hill coefficients of 62 micro M and 2.5 in control, 154 micro M and 1.3 in the presence of GES. 4. GlyR-mediated taurine responses were competitively antagonized by GES. Taurine dose-response curves, in contrast to the glycine dose-response curves were shifted by GES to the right in a parallel manner. 5. The GlyR-block by GES was not voltage-dependent. 6. In contrast to our findings in the mouse, in rat striatal neurons which lack expression of the alpha3 GlyR subunit, GES shifted the glycine dose-response curve to the right in a parallel way without affecting the maximal response. Subtype-specificity of the GES action at GlyR must await further investigation in artificial expression systems. 7. We conclude that GES is a competitive antagonist at GlyR. The antagonistic action of GES at inhibitory ionotropic receptors can explain its epileptogenic action. Care must be taken with the interpretation of data on GES evoked taurine release.

  10. Initial uptake and insulin releasing action of chloromercuribenzene-p-sulphonic acid (CMBS) in suspensions of pancreatic islet cells.

    PubMed

    Idahl, L A; Lernmark, A; Söderberg, M; Winblad, B

    1980-04-01

    The effects of chloromercuribenzene-p-sulphonic acid on dispersed cells prepared from beta-cell-rich ob/ob-mouse islets were studied. 1) Chloromercuribenzene-p-sulphonic acid at concentrations of 0.1 mmol/l or higher diminished cell viability which was partially counteracted by increasing concentrations of bovine serum albumin. 2) The uptake of 203Hg-chloromercuribenzene-p-sulphonic acid after incubation for 4 seconds or longer showed that most of the non-toxic concentrations of chloromercuribenzene-p-sulphonic acid was bound to the cell within 40 seconds. Maximal uptake was achieved after 3 minutes of incubation. The uptake of radioactive chloromercuribenzene-p-sulphonic acid was inhibited by bovine serum albumin. 3) The dynamics of insulin release from perifused dispersed beta-cells embedded in fibrin showed a maximal 40--50-fold stimulation by 0.03 mmol/l chloromercuribenzene-p-sulphonic acid within 10 minutes of perifusion. 4) Scanning electron microscopy of beta-cells revealed no major changes in the cell surface under conditions of maximal binding and insulin releasing effects of chloromercuribenzene-p-sulphonic acid. These data support the concept that the ability of chloromercuribenzene-p-sulphonic acid to induce insulin release is related to its initial binding to the beta-cell surface. The binding of chloromercuribenzene-p-sulphonic acid and the subsequent release of insulin seem to occur without major changes in beta-cell surface morphology.

  11. Detoxification function of the Arabidopsis sulphotransferase AtSOT12 by sulphonation of xenobiotics.

    PubMed

    Chen, Jinhua; Gao, Liqiong; Baek, Dongwon; Liu, Chunlin; Ruan, Ying; Shi, Huazhong

    2015-08-01

    Cytosolic sulphotransferases have been implicated in inactivation of endogenous steroid hormones and detoxification of xenobiotics in human and animals. Yet, the function of plant sulphotransferases in xenobiotic sulphonation and detoxification has not been reported. In this study, we show that the Arabidopsis sulphotransferase AtSOT12 could sulphonate the bacterial-produced toxin cycloheximide. Loss-of-function mutant sot12 exhibited hypersensitive phenotype to cycloheximide, and expression of AtSOT12 protein in yeast cells conferred resistance to this toxic compound. AtSOT12 exhibited broad specificity and could sulphonate a variety of xenobiotics including phenolic and polycyclic compounds. Enzyme kinetics analysis indicated that AtSOT12 has different selectivity for simple phenolics with different side chains, and the position of the side chain in the simple phenolic compounds affects substrate binding affinity and catalytic efficiency. We proposed that the broad specificity and induced production of AtSOT12 may have rendered this enzyme to not only modify endogenous molecules such as salicylic acid as we previously reported, but also sulphonate pathogen-produced toxic small molecules to protect them from infection. Sulphonation of small molecules in plants may constitute a rapid way to inactivate or change the physiochemical properties of biologically active molecules that could have profound effects on plant growth, development and defence.

  12. Geochemical significance of alkylbenzene distributions in flash pyrolysates of kerogens, coals, and asphaltenes

    NASA Astrophysics Data System (ADS)

    Hartgers, Walter A.; Damsté, Jaap S. Sinninghe; de Leeuw, Jan W.

    1994-04-01

    The distribution of C 0-C 5 alkylbenzenes in flash pyrolysates of forty-seven immature kerogens and coals from different geographical locations and of different ages were studied using gas chromatography (GC) in combination with mass spectrometry (MS) in order to decipher the origin of aromatic moieties in macromolecular matter. All possible structural isomers of the alkylated benzenes were determined, and, in some cases, absolute yields were calculated. Sulphur-rich (Type II-S) kerogens yield higher absolute amounts of alkylbenzenes in comparison to Type I, II, and III kerogens. The variations in internal distribution patterns of C 2-C 4 alkylbenzenes were analyzed using multivariate analysis techniques (principal component analysis; PCA). Major variations in alkylbenzene distributions were due to an increased abundance of specific alkylbenzenes, which are related to specific precursor moieties in the macromolecular structure assuming that they are mainly formed via β-cleavage. Alkylbenzenes possessing "linear" carbon skeletons are enhanced in flash pyrolysates of Guttenberg and Estonian Kukersite kerogens (Type I) and are proposed to be derived from linear precursors which have undergone cyclization/aromatization. Relatively high amounts of 1,2,3,4- and 1,2,3,5-tetramethylbenzenes were found in flash pyrolysates of Womble and Duvernay kerogens (Type II) which are likely to be derived from macromolecularly bound diaromatic carotenoids. The relatively high abundance of 1,2,3-trimethylbenzene and 1,3-/1,4-dimethylbenzene in pyrolysates of Monterey kerogens (Type II-S) is proposed to be indicative of the presence of bound nonaromatic carotenoids (e.g., β,β-carotene) which have undergone aromatization and/or loss of methyl groups upon diagenesis. 1-methyl-4-isopropylbenzene, which appears in relatively high amounts in flash pyrolysates of Walcott Chuar kerogen (Type II) and Catalan coals (Type III), is thought to be derived from a heteroatom-bound precursor. These

  13. New extraction method for the analysis of linear alkylbenzene sulfonates in marine organisms. Pressurized liquid extraction versus Soxhlet extraction.

    PubMed

    Alvarez-Muñoz, D; Sáez, M; Lara-Martin, P A; Gómez-Parra, A; González-Mazo, E

    2004-10-15

    A new method has been developed for the determination of linear alkylbenzene sulfonates (LAS) from various marine organisms, and compared with Soxhlet extraction. The technique applied includes the use of pressurized liquid extraction (PLE) for the extraction stage, preconcentration of the samples, purification by solid-phase extraction (SPE) and analysis by liquid chromatography with fluorescence detection. The spiked concentrations were added to the samples (wet mass of the organisms: Solea senegalensis and Ruditapes semidecussatus), which were homogenized and agitated continuously for 25 h. The samples were extracted by pressurized hot solvent extraction using two different extraction temperatures (100 and 150 degrees C) and by traditional Soxhlet extraction. The best recoveries were obtained employing pressurized hot solvent extraction at 100 degrees C and varied in the range from 66.1 to 101.3% with a standard deviation of between 2 and 13. Detection limit was between 5 and 15 microg kg(-1) wet mass using HPLC-fluorescence detection. The analytical method developed in this paper has been applied for LAS determination in samples from a Flow-through exposure system with the objective of measuring the bioconcentration of this surfactant.

  14. Effects and risk assessment of linear alkylbenzene sulfonates in agricultural soil. 2. Effects on soil microbiology as influenced by sewage sludge and incubation time.

    PubMed

    Elsgaard, L; Petersen, S O; Debosz, K

    2001-08-01

    The anionic surfactant linear alkylbenzene sulfonate (LAS) may inhibit soil microorganisms and may occur in agricultural soil through the application of sewage sludge. For five microbial parameters (microbial biomass C and the potentials of iron reduction, ammonium oxidation, dehydrogenase activity, and arylsulfatase activity), we compared the effects of aqueous LAS and LAS-spiked sewage sludge added to existing levels of 0, 3, 8, 22, 22, 62, 174, and 488 mg/kg soil (dry wt) in a Danish sandy agricultural soil that was incubated for 5 d to eight weeks. Arylsulfatase activity (measured after four weeks of incubation) was rather insensitive to LAS, with an EC 10 of 222 and more than 488 mg/kg in soil samples treated with aqueous LAS and LAS-spiked sewage sludge, respectively. For the other microbial parameters, the short-term effects (approximately one to two weeks) of aqueous LAS were characterized by an EC10 in the range of 3 to 39 mg/kg. Application of LAS via sewage sludge generally reduced the short-term effects for the microbial parameters, and the EC10 for LAS in sludge-amended soil after approximately one to two weeks of incubation ranged from less than 8 to 102 mg/kg. Recovery potential was seen for most microbial parameters as a result of prolonged incubation, both under conditions of LAS persistence (anaerobic conditions, the iron-reduction test) and LAS depletion (aerobic incubations, all other assays). In conclusion, the short-term inhibitory effects of LAS on soil microbiology were decreased in the presence of sewage sludge and by a prolonged (two to eight weeks) laboratory incubation period.

  15. Susceptibility of synthetic long-chain alkylbenzenes to degradation in reducing marine sediments

    USGS Publications Warehouse

    Eganhouse, Robert P.; Pontolillo, James

    2008-01-01

    Long-chain alkylbenzenes (LCABs) synthesized for production of alkylbenzene sulfonate surfactants have been used as molecular markers of anthropogenic waste for 25 years. Synthetic LCABs comprise two classes, the tetrapropylene-based alkylbenzenes (TABs) and the linear alkylbenzenes (LABs). LABs supplanted TABs in the mid-1960s because of improved biodegradability of their sulfonated analogs. Use of LCABs for molecular stratigraphy depends on their preservation in sediments over decadal time scales. Most laboratory and field studies suggest that LABs degrade rapidly under aerobic conditions but are resistant to degradation when oxygen is absent. However, recent work indicates that LABs may not be as persistent under reducing conditions as previously thought. To assess the potential for degradation of LCABs in reducing sediments, box cores collected in 1992 and 2003 near a submarine wastewater outfall system were analyzed using gas chromatography/mass spectrometry. The TABs were effectively preserved; differences between whole-core inventories were within analytical error. By contrast, whole-core inventories of the LABs decreased by about 50-60% during the same time interval. Based on direct comparison of chemical inventories in coeval core sections, LAB transformation rates are estimated at 0.07 ±. 0.01 yr-1. These results indicate that caution should be exercised when using synthetic LCABs for reconstruction of depositional records.

  16. Studies on estrification and sulphonation of riboflavin in the environment of highly concentrated sulphuric acid.

    PubMed

    Pajak, Wojciech; Brzezińska, Elzbieta

    2003-01-01

    The article presents investigations of riboflavin reactions in aqueous solutions of sulphuric acid. Analysis of UV/VIS, 1H NMR spectra and TLC indicates that at the beginning of the reaction ester of riboflavin were obtained and then sulphonation reaction took place. From the analysis of UV/VIS spectra the kinetics of the reaction was calculated, using own computer program.

  17. Sulphonic acid derivatives as probes of pore properties of volume-regulated anion channels in endothelial cells.

    PubMed

    Droogmans, G; Maertens, C; Prenen, J; Nilius, B

    1999-09-01

    1. We have used the whole-cell patch-clamp technique to study the effects of 4-sulphonic-calixarenes and some other poly-sulphonic acid agents, such as suramin and basilen blue, on volume-regulated anion channel (VRAC) currents in cultured endothelial cells (CPAE cells). 2. The 4-sulphonic-calixarenes induced a fast inhibition at positive potentials but were ineffective at negative potentials. At small positive potentials, 4-sulphonic-calix[4]arene was a more effective inhibitor than 4-sulphonic-calix[6]arene and -calix[8]arene, which became more effective at more positive potentials. 3. Also suramin and basilen blue induced a voltage dependent current inhibition, reaching a maximum around +40 mV and declining at more positive potentials. 4. The voltage dependence of inhibition was modelled by assuming that these negatively charged molecules bind to a site inside VRAC that senses a fraction delta of the applied electrical field, ranging beween 0.16 to 0.32. 4-Sulphonic-calix[4]arene, suramin and basilen blue bind and occlude VRAC at moderate potentials, but permeate the channel at more positive potentials. 4-Sulphonic-calix[6]arene and -calix[8]arene however do not permeate the channel. From the structural information of the calixarenes, we estimate a lower and upper limit of 11*12 and 17*12 A2 respectively for the cross-sectional area of the pore.

  18. The influence of a surfactant, linear alkylbenzene sulfonate, on the estrogenic response to a mixture of (xeno)estrogens in vitro and in vivo.

    PubMed

    Harris, Catherine A; Brian, Jayne V; Pojana, Giulio; Lamoree, Marja; Booy, Petra; Marcomini, Antonio; Sumpter, John P

    2009-01-18

    The effect of the presence of a surfactant on the activity of a mixture of environmental estrogens was assessed. In their natural habitat, fish are subject not only to exposure to mixtures of estrogenic compounds, as has been addressed in previous publications, but also to other confounding factors (chemical, physical and biological), which may, in theory, affect their responses to such compounds. To assess the potential for such interference, the commonly occurring surfactant, linear alkylbenzene sulfonate (LAS), was applied to the yeast estrogen screen at various concentrations, independently and together with a mixture of estrogens at constant concentrations. LAS enhanced the estrogenic activity of the mixture, an effect which became less pronounced over the course of time. This information was used to design an in vivo study to assess induction of vitellogenin in fathead minnows exposed to the same mixture of estrogens plus LAS. A similar trend was observed, that is, the response was enhanced, but the effect became less pronounced as the study progressed. However, the enhanced response in vivo occurred only at the highest concentration of LAS tested (362microg/L), and was transient because it was no longer apparent by the end of the study. Although LAS is a significant contaminant in terms of both concentration and frequency of detection in the aquatic environment, these data do not suggest that it will have a significant impact on the response of fish to environmental estrogens.

  19. Development of acute toxicity quantitative structure activity relationships (QSAR) and their use in linear alkylbenzene sulfonate species sensitivity distributions.

    PubMed

    Belanger, Scott E; Brill, Jessica L; Rawlings, Jane M; Price, Brad B

    2016-07-01

    Linear Alkylbenzene Sulfonate (LAS) is high tonnage and widely dispersed anionic surfactant used by the consumer products sector. A range of homologous structures are used in laundry applications that differ primarily on the length of the hydrophobic alkyl chain. This research summarizes the development of a set of acute toxicity QSARs (Quantitative Structure Activity Relationships) for fathead minnows (Pimephales promelas) and daphnids (Daphnia magna, Ceriodaphnia dubia) using accepted test guideline approaches. A series of studies on pure chain length LAS from C10 to C14 were used to develop the QSARs and the robustness of the QSARs was tested by evaluation of two technical mixtures of differing compositions. All QSARs were high quality (R(2) were 0.965-0.997, p < 0.0001). Toxicity normalization employing QSARs is used to interpret a broader array of tests on LAS chain length materials to a diverse group of test organisms with the objective of developing Species Sensitivity Distributions (SSDs) for various chain lengths of interest. Mixtures include environmental distributions measured from exposure monitoring surveys of wastewater effluents, various commercial mixtures, or specific chain lengths. SSD 5th percentile hazardous concentrations (HC5s) ranged from 0.129 to 0.254 mg/L for wastewater effluents containing an average of 11.26-12 alkyl carbons. The SSDs are considered highly robust given the breadth of species (n = 19), use of most sensitive endpoints from true chronic studies and the quality of the underlying statistical properties of the SSD itself. The data continue to indicate a low hazard to the environment relative to expected environmental concentrations.

  20. Increasing maturity of kerogen type II reflected by alkylbenzene distribution from pyrolysis-gas chromatography-mass spectrometry

    USGS Publications Warehouse

    Lis, G.P.; Mastalerz, Maria; Schimmelmann, A.

    2008-01-01

    A series of Late Devonian to Early Mississippian type II kerogens with vitrinite reflectance values Ro 0.29-2.41% were analyzed using py-GC-MS. In addition, a low maturity kerogen with Ro 0.44% was separated into fractions via density gradient centrifugation, followed by py-GC-MS of the alginite and amorphinite maceral concentrates. Alkylbenzenes and n-alk-1-ene/n-alkane doublets represented the main compound classes identified in all pyrolysates. The pyrolysate from alginite featured 1,2,4-trimethylbenzene and toluene as the two most prominent alkylbenzenes. In contrast, alkylbenzenes in pyrolysates from amorphinite and low maturity bulk kerogens with Ro 0.29-0.63% were dominated by 1,2,3,4-tetramethylbenzene. With increasing thermal maturity, pyrolysates were increasingly dominated by (i) alkylbenzenes with fewer methyl groups, namely by tri- and dimethylbenzenes at medium maturity (Ro 0.69-1.19%), and (ii) by toluene at higher maturity (Ro 1.30-2.41%). With increasing maturity of kerogen type II, the decreasing abundance of highly methyl-substituted alkylbenzenes and the parallel increase in less methyl-substituted alkylbenzenes in flash pyrolysates suggest that demethylation is an important chemical process in the thermal maturation of kerogen type II. ?? 2008 Elsevier Ltd. All rights reserved.

  1. Adsorption and wettability study of methyl ester sulphonate on precipitated asphaltene

    NASA Astrophysics Data System (ADS)

    Okafor, H. E.; Sukirman, Y.; Gholami, R.

    2016-03-01

    Asphaltene precipitation from crude oil and its subsequent aggregation forms solid, which preferentially deposit on rock surfaces causing formation damage and wettability changes leading to loss of crude oil production. To resolve this problem, asphaltene inhibitor has been injected into the formation to prevent the precipitation of asphaltene. Asphaltene inhibitors that are usually employed are generally toxic and non-biodegradable. This paper presents a new environmentally friendly asphaltene inhibitor (methyl ester sulphonate), an anionic surfactant, which has excellent sorption on formation rock surfaces. Result from adsorption study validated by Langmuir and Freundlich models indicate a favourable adsorption. At low volumes injected, methyl ester sulphonate is capable of reverting oil-wet sandstone surface to water-wet surface. Biodegradability test profile shows that for concentrations of 100-5000ppm it is biodegradable by 65-80%.

  2. Investigations on the electrical and structural properties of polyaniline doped with camphor sulphonic acid

    NASA Astrophysics Data System (ADS)

    Saravanan, S.; Joseph Mathai, C.; Anantharaman, M. R.; Venkatachalam, S.; Prabhakaran, P. V.

    2006-07-01

    Polyaniline is chemically synthesised and doped with camphor sulphonic acid. FTIR studies carried out on these samples indicate that the aromatic rings are retained after polymerisation. The percentage of crystallinity for polyaniline doped with camphor sulphonic acid has been estimated from the X-ray diffraction studies and is around 56% with respect to polyaniline emeraldine base. The change in dielectric permittivity with respect to temperature and frequency is explained on the basis of interfacial polarisation. AC conductivity is evaluated from the observed dielectric permittivity. The values of AC and DC conductivity and activation energy are calculated. The activation energy values suggested that the hopping conduction is the prominent conduction mechanism in this system.

  3. Complete oxidation of linear alkylbenzene sulfonate by bacterial communities selected from coastal seawater.

    PubMed Central

    Sigoillot, J C; Nguyen, M H

    1992-01-01

    Anionic surfactants, especially alkylbenzene sulfonates, are discharged into marine areas in great quantities. Because of their poor biodegradability, linear alkylbenzene sulfonates accumulate in seawater and sediments. Bacterial communities that can degrade surfactants were selected from coastal seawater contaminated by urban sewage. All the isolated strains consisted of gram-negative, strictly aerobic rods or helical bacteria. Some of these, though isolated from coastal seawater, did not need sodium for growth and appeared to be related to the genera Alcaligenes and Pseudomonas. Complete surfactant biodegradation was achieved by three important steps: terminal oxidation of the alkyl chain, desulfonation, and aromatic-ring cleavage. Only a few strains were able to carry out the first two steps. The aromatic ring was then cleaved by other strains that possess very specific enzymatic activities. Finally, a number of strains grew on short acids that were end-of-metabolism products of the others. PMID:1599249

  4. Metabolism of sulphonated anthraquinones in rhubarb, maize and celery: the role of cytochromes P450 and peroxidases.

    PubMed

    Page, Valérie; Schwitzguébel, Jean-Paul

    2009-11-01

    Sulphonated anthraquinones are precursors of many synthetic dyes and pigments, recalcitrant to biodegradation, and thus contaminating many industrial effluents and rivers. In the development of a phytotreatment to remove sulphonated aromatic compounds, rhubarb (Rheum rhaponticum), a plant producing natural anthraquinones, as well as maize (Zea mays) and celery (Apium graveolens), plants not producing anthraquinones, were tested for their ability to metabolise these xenobiotics. Plants were cultivated under hydroponic conditions, with or without sulphonated anthraquinones, and were harvested at different times. Either microsomal or cytosolic fractions were prepared. The monooxygenase activity of cytochromes P450 towards several sulphonated anthraquinones was tested using a new method based on the fluorimetric detection of oxygen consumed during cytochromes P450-catalysed reactions. The activity of cytosolic peroxidases was measured by spectrophotometry, using guaiacol as a substrate. Results indicated that the activity of cytochromes P450 and peroxidases significantly increased in rhubarb plants cultivated in the presence of sulphonated anthraquinones. A higher activity of cytochromes P450 was also detected in maize and celery exposed to the pollutants. In these two plants, a peroxidase activity was also detected, but without a clear difference between the control plants and the plants exposed to the organic contaminants. This research demonstrated the existence in rhubarb, maize and celery of biochemical mechanisms involved in the metabolism and detoxification of sulphonated anthraquinones. Taken together, results confirmed that rhubarb might be the most appropriate plant for the phytotreatment of these organic pollutants.

  5. Trivalent chromium removal from aqueous solutions by a sol–gel synthesized silica adsorbent functionalized with sulphonic acid groups

    SciTech Connect

    Gomez-Gonzalez, Sergio Efrain; Carbajal-Arizaga, Gregorio Guadalupe; Manriquez-Gonzalez, Ricardo; De la Cruz-Hernandez, Wencel; Gomez-Salazar, Sergio

    2014-11-15

    Highlights: • Corpuscular sulphonic acid-functionalized silica holds improved uptake of chromium. • Mesopores on adsorbent facilitate (CH{sub 3}COO){sub 2}Cr{sup +} ion uptake on sulphonate sites. • Formation of chromium acetate sulphonate complex proposed from XPS results. • Fixed bed chromium uptake results suggest potential industrial use. - Abstract: A high capacity hybrid silica adsorbent was synthesized via sol–gel processing with sulphonic acid groups as trivalent chromium complex ions chelators from aqueous solutions. The synthesis included co-condensation of tetraethoxysilane (TEOS) with 3-(mercaptopropyl)trimethoxysilane (MPS), and oxidation of thiol to sulphonic acid groups. Chromium uptake kinetic, batch and fixed-bed experiments were performed to assess the removal of this metal from aqueous solutions. {sup 13}C, {sup 29}Si CPMAS NMR, FTIR, XPS were used to characterize the adsorbent structure and the nature of chromium complexes on the adsorbent surface. Chromium maximum uptake was obtained at pH 3 (72.8 mg/g). Elemental analysis results showed ligand density of 1.48 mmol sulphonic groups/g. About 407 mL of Cr(III) solution (311 mg/L) were treated to breakthrough point reaching ≤0.06 mg/L at the effluent. These results comply with USEPA regulation for chromium concentration in drinking water (≤0.1 mg/L). The adsorbent shows potential to be used in chromium separations to the industrial level.

  6. Sulphonated imidized graphene oxide (SIGO) based polymer electrolyte membrane for improved water retention, stability and proton conductivity

    NASA Astrophysics Data System (ADS)

    Pandey, Ravi P.; Shahi, Vinod K.

    2015-12-01

    Sulphonated imidized graphene oxide (SIGO) (graphene oxide (GO) tethered sulphonated polyimide) has been successfully synthesized by polycondensation reaction using dianhydride and sulphonated diamine. Polymer electrolyte membranes (PEMs) are prepared by using SIGO (different wt%) and sulphonated poly(imide) (SPI). Resultant SPI/SIGO composite PEMs exhibit improved stabilities (thermal, mechanical and oxidative) and good water-retention properties (high bound water content responsible for proton conduction at high temperature by internal self-humidification). Incorporation of covalent bonded SIGO into SPI matrix results hydrophobic-hydrophilic phase separation and facile architecture of proton conducting path. Well optimized sulphonated poly(imide)/sulphonated imidized graphene oxide (15 wt%) (SPI/SIGO-15) composite membrane shows 2.24 meq g-1 ion-exchange capacity (IEC); 11.38 × 10-2 S cm-1 proton conductivity; 5.12% bound water content; and 10.52 × 10-7 cm2 s-1 methanol permeability. Maximum power density for pristine SPI membrane (57.12 mW cm-2) improves to 78.53 mW cm-2 for SPI/SIGO-15 membrane, in single-cell direct methanol fuel cell (DMFC) test at 70 °C using 2 M methanol fuel. Under similar experimental conditions, Nafion 117 membrane exhibits 62.40 mW cm-2 maximum power density. Reported strategy for the preparation of PEMs, offers a useful protocol for grafting of functionalized inorganic materials with in organic polymer chain by imidization.

  7. Utilization of alkylbenzenes during anaerobic growth of pure cultures of denitrifying bacteria on crude oil

    SciTech Connect

    Rabus, R.; Widdel, F.

    1996-04-01

    Leakage from oil pipelines and underground fuel tanks may result in contamination of soils and deeper horizons. Even though the equilibrium partitioning of BTEX (benzene, toluene, ethylbenzene, and xylenes) between oil and water is largely on the side of the hydrophobic phase, BTEX exhibit a certain water solubility higher than other oil hydrocarbons. This study evaluates the growth of four strains of denitrifying bacteria on crude oil and the resulting, strain-specific depletion of alkylbenzenes.

  8. Excited triplet state photophysics of the sulphonated aluminium phthalocyanines bound to human serum albumin.

    PubMed

    Foley, M S; Beeby, A; Parker, A W; Bishop, S M; Phillips, D

    1997-03-01

    The binding of the sulphonated aluminum phthalocyanines to human serum albumin (HSA) in aqueous phosphate buffer solution at 25 degrees C has been studied by measuring the properties of the triplet excited states of these dyes. The triplet lifetimes were measured by triplet-triplet absorption flash photolysis. The triplet lifetime of the disulphonated AlS2Pc (2.5 microM) varies from 500 +/- 30 microseconds in the absence of protein to 1.100 microseconds and longer with HSA concentrations above 100 microM. Under identical conditions, the maximum triplet lifetimes of the mono-, tri- and tetrasulphonated compounds bound to HSA are shorter than those for the disulphonated species. The increase in the triplet state lifetimes is attributed to the ability of the bulk aqueous phase to interact with the sensitizer at the site of binding; the site of binding being dependent on the degree of sulphonation. For AlS2Pc and AlS3Pc at all HSA concentrations, and regardless of the degree of sulphonation, all the triplet state decay profiles follow simple pseudo-first-order kinetics. The exponential decay of the triplet phthalocyanine at all HSA concentrations is ascribed to the rapid association and dissociation of the phthalocyanine-HSA complex on the time-scales of the triplet state lifetimes. A simplified one-step binding model is utilized to describe the results. The association of AlS1Pc with HSA results in substantial quenching of the triplet state quantum yield, and a more complex model is required to analyze the results. The tetrasulphonated compound (AlS4Pc) binds to the protein at a site where it experiences some protection from the aqueous phase.

  9. Room temperature ppb level Cl2 sensing using sulphonated copper phthalocyanine films.

    PubMed

    Kumar, Arvind; Singh, A; Debnath, A K; Samanta, S; Aswal, D K; Gupta, S K; Yakhmi, J V

    2010-09-15

    We present room temperature chemiresistive gas sensing characteristics of drop casted sulphonated copper phthalocyanine (CuTsPc) films. It has been demonstrated that these films are highly selective to Cl(2) and the sensitivity in the 5-2000 ppb range varies linearly between 65 and 625%. However, for concentrations >or=2000 ppb, the response becomes irreversible, which is found to be due to the chemical bond formation between Cl(2) and SO(3)Na group of CuTsPc films. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) data confirms the oxidation of SO(3)Na group by Cl(2) gas.

  10. [Preliminary Study on Linear Alkylbenzenes as Indicator for Process of Urbanization].

    PubMed

    Xu, Te; Zeng, Hui; Ni, Hong-Gang

    2016-01-15

    In this study, we selected Shenzhen City as a typical region of urbanization and took Linear alkylbenzenes ( LABs) as an environmental molecular marker to investigate the relationship between soil LABs levels and urbanization indexes on the basis of analysis of spatial distribution of LABs in surface soil. Our results indicated relations between the LABs levels in soil and the five urbanization indexes, such as the population, water supply, urban construction, income and expenditure, as well as industrial structure. These results suggested that LABs levels were correlated with urbanization and could be used as an environmental molecular indicator for the process of urbanization.

  11. Prophylactic treatment with sulphonated immunoglobulin G attenuates development of mechanical allodynia-like response in mice with neuropathic pain

    PubMed Central

    YAMAMOTO, Wataru; ITANO, Yasuhiro; KOBAYASHI, Tsunefumi; MIURA, Daishiro; KASAHARA, Yoshinori

    2015-01-01

    Human immunoglobulin G (IgG) concentrates are immune-modulating, anti-inflammatory plasma-derived products. Clinical studies in recent years have suggested that IgG attenuates neuropathic pain. In this study, effects of sulphonated IgG on the development and maintenance of a mechanical allodynia-like response were examined in mice with neuropathic pain induced by a partial sciatic nerve ligation (PSL). When sulphonated IgG (400 or 1,000 mg/kg/day, i.p.) was administered for 5 days, from 1 day before surgery to post-operative day (POD) 3, the development of a mechanical allodynia-like response was attenuated. On the other hand, sulphonated IgG had little effect on the maintenance of a mechanical allodynia-like response when administered for 5 days, from POD 11 to POD 15, at which time a mechanical allodynia-like response had already been developed. To explore the mechanism of sulphonated IgG, the mRNA expression of inflammatory cytokines was evaluated in the injured sciatic nerve. Sulphonated IgG (1,000 mg/kg/day, i.p.) that was administered for 3 days, from 1 day before surgery to POD 1, significantly attenuated the up-regulation of tumor necrosis factor-α and monocyte chemotactic protein-1 mRNAs on POD 1. These results suggest that prophylactic treatment with sulphonated IgG attenuates the development of mechanical allodynia-like response by inhibition of inflammatory cytokine expression in mice with PSL. PMID:26321444

  12. Time-resolved spectroscopic studies of sulphonated aluminium phthalocyanine triplet states

    NASA Astrophysics Data System (ADS)

    Simpson, Mary S. C.; Beeby, A.; Bishop, Steven M.; MacRobert, Alexander J.; Parker, Andrew W.; Phillips, David

    1992-04-01

    The photophysical and photochemical properties of sulphonated aluminum and zinc phthalocyanines have been investigated in a range of solvents and model biological systems. Anomalous effects are observed upon deuteration of the solvent and addition of fluoride ions. In D2O the excited singlet and triplet state lifetimes and quantum yields of fluorescence and triplet state formation are increased relative to H2O. No solvent isotope effect is observed between CH3OH and CH3OD. It is proposed that relaxation of the excited state involves a tunnelling type interaction in which the phthalocyanine's highly energetic metal-axial ligand stretching vibrations are coupled to the HO-H or DO-D stretching vibrations. A significant increase in triplet lifetimes of phthalocyanine sensitizers bound to protein substrates is observed which is a function of the degree of sulphonation. The implications of these results to the determination of the quantum yields of singlet oxygen formation in D2O and lipophilic environments are discussed.

  13. Cellular inhibition of microtubule assembly by photoactivated sulphonated meso-tetraphenylporphines.

    PubMed

    Berg, K; Moan, J; Bommer, J C; Winkelman, J W

    1990-09-01

    This work relates to studies on modes of phototoxicity by sulphonated mesotetraphenylporphines on cultured cells. Toxicity appears to be related to inhibition of microtubule function. Treatment of human cervix carcinoma cells of the line NHIK 3025 incubated for 18 h with meso-tetraphenylporphine sulphonates (TPPSn where n = 2a, 2o or 4) and exposed to light, inhibits multiplication for the first hours after light exposure, a significant fraction of the cells accumulating in mitosis. The maximal number of cells in mitosis after treatment (approximately 20%) is dependent on the fluence but is similar for all three photosensitizers. For the first hours after treatment the mitotic cells were always mainly in metaphase; mainly seen as c-metaphases and three-group metaphases. During this time anaphase and telophase cells were absent or greatly reduced in number. Indirect immunofluorescence staining of beta-tubulin showed that the spindle apparatus of mitotic cells was perturbed in all cases. Results are presented which indicate that photoactivation of TPPSn located on the plasma membrane destroys microtubules in interphase cells and leads to arrest of the cells in mitosis. The localization of the dye which sensitizes the photoinduced perturbation of microtubules is further discussed.

  14. Incomplete degradation of linear alkylbenzene sulfonate surfactants in Brazilian surface waters and pursuit of their polar metabolites in drinking waters.

    PubMed

    Eichhorn, Peter; Rodrigues, Silvana V; Baumann, Wolfram; Knepper, Thomas P

    2002-02-04

    In Brazil more than 90% of the population are not connected to municipal wastewater treatment plants. As a consequence, surface waters receive continuously considerable amounts of untreated domestic sewage containing surfactants as a major constituent. Such polluted waters gave rise to special interest if they are used as a source for the production of drinking water. In this work, the river Rio Macacu (State Rio de Janeiro, Brazil) was monitored for the occurrence of the most widely used anionic surfactant linear alkylbenzene sulfonate (LAS) together with its main degradative product, sulfophenyl carboxylates (SPC). In order to pursue the fate of both compounds after emission into the river, samples were collected at several locations along the river bank, and analyzed applying liquid chromatography-mass spectrometry after enrichment by solid-phase extraction. The LAS concentrations ranged between 14 and 155 microg l(-1) and the levels of their metabolic intermediates were found from 1.2 to 14 microg l(-1). The self-purification capacity of the water was impressively demonstrated in the upper course of the river downstream of a town considered as one major discharge point, whereas in the lower course the relative constant concentrations of both analytes were detected which was explained with an overall increasing level of pollution. Furthermore, a series of drinking water samples from Niterói and São Gonçalo, supplied by the same waterworks treating surface waters from the Rio Macacu, were taken during two sampling periods and examined for the presence of the strongly polar SPC which is suspected of by-passing the purification processes. The levels detected in the drinking water ranged between 1.6 and 3.3 microg l(-1). For the analyses of drinking and surface waters the peak pattern of a selected SPC homologue composed by several positional isomers served as an indicator to describe the progression of SPC degradation occurred in the river and could be used to

  15. Solid-Phase Contact Assay That Uses a lux-Marked Nitrosomonas europaea Reporter Strain To Estimate Toxicity of Bioavailable Linear Alkylbenzene Sulfonate in Soil

    PubMed Central

    Brandt, Kristian K.; Pedersen, Anders; Sørensen, Jan

    2002-01-01

    Information about in situ toxicity of the bioavailable pools of adsorptive soil pollutants is a prerequisite for proper ecological risk assessment in contaminated soils. Such toxicity data may be obtained by assays allowing for direct exposure of introduced test microorganisms to the toxicants, as they appear in solid solution equilibria in the natural soil. We describe a novel sensitive solid-phase contact assay for in situ toxicity testing of soil pollutants based on a recombinant bioluminescent reporter strain of Nitrosomonas europaea. A slurry of the reporter strain and soil sample was shaken for 1 h, after which bioluminescence was measured either directly (soil slurry protocol) or in the supernatant obtained after centrifugation (soil extract protocol). The assay was validated for both protocols by using linear alkylbenzene sulfonate (LAS) as a toxic and adsorptive model compound in the soil samples. Interestingly, LAS showed the same toxicity to the reporter strain with either soil incubation (both protocols) or pure culture, suggesting that adsorbed LAS pools contributed to the observed toxicity. The solid-phase contact assay that used the reporter strain of lux-marked N. europaea was slightly more sensitive for the detection of LAS toxicity in soil than activity-based assays targeting indigenous nitrifiers and much more sensitive than assays targeting indigenous heterotrophic microbes. We conclude that the new solid-phase contact assay, which is based on direct interaction of the test microorganisms with bioavailable pools of the toxicants in soil, provides a most sensitive and relevant method for evaluating the in situ toxicity and assessing the risks of soil contaminants. PMID:12089034

  16. Sensory reactions of nasal pungency and odor to volatile organic compounds: the alkylbenzenes.

    PubMed

    Cometto-Muñiz, J E; Cain, W S

    1994-09-01

    Research assessed the independent contribution of the trigeminal and olfactory nerves to the detection of airborne chemicals by measuring nasal detection thresholds in subjects clinically diagnosed as lacking a functional sense of smell (anosmics) and in matched normal controls (normosmics). Anosmics can provide only odor-unbiased pungency thresholds. Normosmics provided odor thresholds. Stimuli included homologous alkylbenzenes (from toluene to octylbenzene), chlorobenzene, 1-octene, and 1-octyne. As seen before with homologous alcohols, acetates, and ketones, both types of threshold declined with increasing carbon chain length. Anosmics failed to detect alkylbenzenes above propylbenzene. The strong linear correlation between pungency thresholds and saturated vapor concentration for all tested compounds, as a whole, and the constancy of pungency thresholds expressed as percent of vapor saturation, suggests that nasal pungency from these substances relies heavily on a broadly tuned physicochemical interaction with a susceptible biophase within the cell membrane. Through such a nonspecific mechanism, low, subthreshold levels of a wide variety of volatile organic compounds of low reactivity-as found in many polluted indoor spaces-could add their sensory impact to precipitate noticeable sensory irritation.

  17. Behaviour of the isothermal retention indices of n-alkylbenzenes on stationary phases of different polarity.

    PubMed

    Santiuste, José María; Quintanilla-López, Jesús Eduardo; Takács, Jószef M; Lebrón-Aguilar, Rosa

    2012-01-27

    Isothermal retention indices (I) of benzene, toluene, ethylbenzene, n-propylbenzene and n-butylbenzene were determined at 323-423 K on twelve WCOT capillary columns covering a broad stationary phase polarity spectrum. These I values have been tested carrying out a comparison with the NIST database values. The effect of the stationary phase polarity on I values was studied. But for the poly(3,3,3-trifluoropropylmethyl siloxane) column, a good linear correlation was found. At each temperature, the dependence on I of the alkyl chain length (z) attached to the ring of the n-alkylbenzenes was linear and of similar magnitude for the stationary phases of low to middle polarity, but lower for the more polar ones. Moreover, an important influence of the column temperature on the slope of the I vs. z plots was observed for the only non polysiloxane-type stationary phase studied, i.e., poly(ethylene glycol), due to its higher chain stiffness. Finally, different expressions describing the effect of the temperature on the retention index have been compared. I values of the n-alkylbenzenes in the 323-423 K range increase with increasing column temperature according to the Antoine-type (I=α+β(γ+T)(-1)) and the extended (I=a+bT(-1)+clnT) models. No significant differences were observed between them, except for the poly[70% bis(3-cyanopropyl) 30% dimethyl silphenylene-siloxane] column, for which the Antoine-type model was slightly better.

  18. Molar volumes of ethylcyclohexane and butyronitrile glasses resulting from vapor deposition: dependence on deposition temperature and comparison to alkylbenzenes.

    PubMed

    Nakayama, Hideyuki; Omori, Kio; Ino-u-e, Katsunobu; Ishii, Kikujiro

    2013-09-05

    Molar volumes (Vm) of vapor-deposited ethylcyclohexane (ECH) and butyronitrile (BN, sometimes called butanenitrile) glasses were studied as a function of deposition temperature (Td). ECH glasses deposited at Td sufficiently below their glass-transition temperature (Tg) exhibited changes in Vm on heating similarly to alkylbenzenes. At Td close to Tg, ECH formed dense glasses as alkylbenzenes do, although these glasses were only slightly more dense than its supercooled liquid (SCL) states at the same temperatures. For BN, no indication of the formation of dense glasses was observed even at Td close to Tg, and the variations in Vm with the temperature elevation were different from those of alkylbenzenes. Analysis of the initial Vm of the deposited glasses of different compounds demonstrated that its Td-dependence was well correlated with the steepness index (m) of the corresponding SCL. Quantum-chemical calculations concerning dimer formation by the studied compounds showed that the hydrogen bond between a C-H bond in the alkyl group and π-electrons in the phenyl ring stabilizes the alkylbenzene dimers, suggesting the possibility of the dense glass formation and large m of these compounds. The small m value of BN was also discussed on the basis of the calculation results.

  19. Augmented lipid accumulation in ethyl methyl sulphonate mutants of oleaginous microalga for biodiesel production.

    PubMed

    Mehtani, Juhi; Arora, Neha; Patel, Alok; Jain, Priyanka; Pruthi, Parul A; Poluri, Kirshna Mohan; Pruthi, Vikas

    2017-03-21

    The aim of this work was to generate high lipid accumulating mutants of Chlorella minutissima (CM) using ethyl methyl sulphonate (EMS) as a random chemical mutagen. Amid the 5% surviving cells after exposure to EMS (2M), three fast growing mutants (CM2, CM5, CM7) were selected and compared with wild type for lipid productivity and biochemical composition. Among these mutants, CM7 showed the maximum biomass (2.4g/L) and lipid content (42%) as compared to wild type (1.5g/L; 27%). Further, the mutant showed high photosynthetic pigments with low starch content signifying the re-allocation of carbon flux to lipid. The obtained mutant showed no visible morphological changes in comparison to its WT. The fatty acid profile showed increase in monounsaturated fatty acids while decreased saturated and polyunsaturated fatty acids signifying good quality biodiesel. The mutant strain thus obtained can be optimized further and applied for enhanced biodiesel production.

  20. Factors affecting interactions between sulphonate-terminated dendrimers and proteins: A three case study.

    PubMed

    González-García, Estefanía; Maly, Marek; de la Mata, Francisco Javier; Gómez, Rafael; Marina, María Luisa; García, María Concepción

    2017-01-01

    This work proposes a deep study on the interactions between sulphonate-terminated carbosilane dendrimers and proteins. Three different proteins with different molecular weights and isoelectric points were employed and different pHs, dendrimer concentrations and generations were tested. Variations in fluorescence intensity and emission wavelength were used as protein-dendrimer interaction probes. Interaction between dendrimers and proteins greatly depended on the protein itself and pH. Other important issues were the dendrimer concentration and generation. Protein-dendrimer interactions were favored under acidic working conditions when proteins were positively charged. Moreover, in general, high dendrimer generations promoted these interactions. Modeling of protein-dendrimer interactions allowed to understand the different behaviors observed for every protein.

  1. Determination of protein by resonance light scattering technique using dithiothreitol-sodium dodecylbenzene sulphonate as probe

    NASA Astrophysics Data System (ADS)

    Wu, Lihang; Mu, Dan; Gao, Dejiang; Deng, Xinyu; Tian, Yuan; Zhang, Hanqi; Yu, Aimin

    2009-02-01

    The resonance light scattering (RLS) spectra of bovine serum albumin (BSA)-dithiothreitol (DTT)-sodium dodecylbenzene sulphonate (SDBS) and its analytical application were investigated. The RLS intensity of this system can be effectively enhanced in the presence of BSA. Based on the enhanced RLS intensity, a simple assay for BSA was developed. The experimental results indicate that the enhanced RLS intensity is proportional to the concentration of BSA in the range from 1.0 × 10 -8 to 7.5 × 10 -7 mol L -1 with the determination limit of 5.0 × 10 -9 mol L -1. The effects of pH, concentration of SDBS and DTT on the RLS enhancement were discussed. Most metal ions have little interference on the determination of BSA. Some synthetic and real samples were analyzed, and the results obtained were in good agreement with those obtained by Bradford method.

  2. High chrome exhaustion in a non-float tanning process using a sulphonic aromatic acid.

    PubMed

    Bacardit, Anna; Morera, Josep M; Ollé, Lluís; Bartolí, Esther; Dolors Borràs, M

    2008-10-01

    Tanning processes performed in drums consume large amounts of water and chemicals, most of which end up in the wastewater. This study explores an alternative approach at an industrial scale to the traditional pickle-chrome tanning method. The new method replaces formic and sulphuric acids with sulphonic aromatic acid. Because it is done without float, there is a sizeable reduction in the amount of added salt and chrome salt as well as an increase in temperatures at the end of the tanning process. From an environmental perspective, the new method offers important advantages. For instance, there is no float addition in the tannage. Also, there are reductions of 94% and 99%, respectively, in the discharge of chlorides and chrome, as well as a 75% reduction in the residual float. Our financial assessment demonstrated that the new method is 42% cheaper than a traditional approach.

  3. Histomorphometric evaluation of experimentally induced colitis with trinitrobenzene-sulphonic acid in rats

    PubMed Central

    RABAU, MICHA; EYAL, AMI; DAYAN, DAN

    1996-01-01

    Colitis was induced with trinitrobenzene-sulphonic acid (TNB) in rats and a histomorphometric study was performed as a possible scoring system for disease activity. The affected colon was examined 10, 20, 40 and 60 days after TNB administration. Quantitative microscopic analysis was performed on the following histologic parameters: necrosis, mucosal epithelium, muscularis fibres, inflammation, granulation tissue and fibrosis. Clinically, the rats were sick, especially on days 10 and 20 after TNB injection. Concomitantly, a peak necrosis score involving the full thickness of the colonic wall was recorded on day 10. The inflammatory reaction was most intense 20 days after TNB injection. After 60 days, marked epithelial regeneration was seen and most of the inflammatory reaction had subsided. A good correlation was found between clinical features and quantitative histomorphometric characteristics of colitis. The criteria described allow a precise description and quantification of the inflammatory and healing process of TNB-induced colitis in rats. PMID:8943736

  4. The scale epithelium as a novel, non-invasive tool for environmental assessment in fish: Testing exposure to linear alkylbenzene sulfonate.

    PubMed

    Alves, R M S; Pereira, B F; Ribeiro, R G L G; Pitol, D L; Ciamarro, C M; Valim, J R T; Caetano, F H

    2016-07-01

    Increasing pollution levels have turned our attention to assessing lethal and sublethal effects of toxic agents using the most informative techniques possible. We must seek non-invasive or non-lethal sampling methods that represent an attractive alternative to traditional techniques of environmental assessment in fish. Detergents are amongst the most common contaminants of water bodies, and LAS (Linear Alkylbenzene Sulfonate) is one of the most used anionic surfactant on the market. Our study analyzed morphological alterations (histological and histochemical) of the scale epithelium of Prochilodus lineatus under exposure to two concentrations of LAS, 3.6mg/L and 0.36mg/L, for a period of 30 days and evaluated at 14, 21 and 30 days. In order to establish morphological analysis of the scale epithelium as a new non-lethal environmental assessment tool that is reliable and comparable to classic methods, the relative sensibility of this technique was compared to a commonly used method of environmental assessment in fish, the estimation of the effects of pollutants upon branchial morphology. Two experiments were carried out, testing animals in tanks, and in individual aquariums. Results of analyses on gill tissue show that exposure to 3.6mg/L of surfactant caused severe damage, including hyperplasia, hypertrophy and fusion at 14 days, with aneurisms at 21 and 30 days; while exposure to 0.36mg/L had lighter effects on the organ, mainly lower incidence of fusion and hyperplasia. Aditionally, scale morphology was altered severely in response to 3.6mg/L of LAS, consistently showing increased mucous and club cell production. Epithelial thickness was the most variable parameter measured. Scale epithelium sensibility has the potential to be a reliable environmental marker for fish species since it has the advantage of being less invasive when compared to traditional methods. However, more studies are required to increase the robustness of the technique before it can be

  5. Surface properties of pillared acid-activated bentonite as catalyst for selective production of linear alkylbenzene

    NASA Astrophysics Data System (ADS)

    Faghihian, Hossein; Mohammadi, Mohammad Hadi

    2013-01-01

    Acid-activated and pillared montmorillonite were prepared as novel catalysts for alkylation of benzene with 1-decene for production of linear alkylbenzene. The catalysts were characterized by X-ray diffraction, FT-IR spectroscopy, N2 adsorption isotherms, temperature programmed desorption of NH3, scanning electron microscopy and elemental and thermal analysis techniques. It was found that acid-activation of clays prior to pillaring increased the porosity, total specific surface area, total pore volume and surface acidity of the catalysts. Optimization of the reaction conditions was performed by varying catalyst concentration (0.25-1.75 wt%), reactants ratio (benzene to 1-decene of 8.75, 12 and 15) and temperature (115-145 °C) in a batch slurry reactor. Under optimized conditions more than 98% conversion of 1-decene, and complete selectivity for monoalkylbenzenes were achieved.

  6. Aqueous solubilities, vapor pressures, and 1-octanol-water partition coefficients for C9-C14 linear alkylbenzenes

    USGS Publications Warehouse

    Sherblom, P.M.; Gschwend, P.M.; Eganhouse, R.P.

    1992-01-01

    Measurements and estimates of aqueous solubilities, 1-octanol-water partition coefficients (Kow), and vapor pressures were made for 29 linear alkylbenzenes having alkyl chain lengths of 9-14 carbons. The ranges of values observed were vapor pressures from 0.002 to 0.418 Pa, log Kow, from 6.83 to 9.95, and aqueous solubilities from 4 to 38 nmol??L-1. Measured values exhibited a relationship to both the alkyl chain length and the position of phenyl substitution on the alkyl chain. Measurement of the aqueous concentrations resulting from equilibration of a mixture of alkylbenzenes yielded higher than expected values, indicating cosolute or other interactive effects caused enhanced aqueous concentrations of these compounds. ?? 1992 American Chemical Society.

  7. Study on the inclusion complexes of cyclodextrin and sulphonated azo dyes by electrospray ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Zhang, Huarong; Chen, Gang; Wang, Ling; Ding, Lan; Tian, Yuan; Jin, Weiqun; Zhang, Hanqi

    2006-05-01

    The inclusion complexes of [alpha]-, [beta]-cyclodextrin ([alpha]-, [beta]-CD) and sulphonated azo dyes ligands (Orange II, Ponceau SX, Allura red AC and Tartrazine) were studied by electrospray ionization mass spectrometry (ESI-MS) and the dissociation constants (KD) of the inclusion complexes were determined. A new method to obtain the dissociation constants of CD-ligand inclusion complexes without curve fitting was developed. Once the total concentrations of CD and ligand have been known, KD can be calculated from the sum peak intensities of free CD and inclusion complex and the number of binding site can be obtained from the mass spectrum. Ponceau SX, Allura red AC and Tartrazine binding to [alpha]-CD form 1:1 inclusion complexes with KD values of 1.33 × 10-5 mol L-1, 4.85 × 10-6 mol L-1 and 7.47 × 10-5 mol L-1, respectively. The obtained KD values of the inclusion complexes of above-mentioned three sulphonated azo dyes ligands binding to [beta]-CD in turn are 3.93 × 10-6 mol L-1, 6.50 × 10-6 mol L-1 and 1.12 × 10-4 mol L-1, respectively. The 1:1 and 1:2 inclusion complexes are found in the systems of CD and Orange II. KD,1 and KD,2 of [alpha]-CD and Orange II inclusion complexes are 4.05 × 10-4 mol L-1 and 4.60 × 10-7 (mol L-1)2, respectively. 3.94 × 10-5 mol L-1 and 1.72 × 10-7 (mol L-1)2 are the KD,1 and KD,2 of [beta]-CD and Orange II inclusion complexes, respectively. The competition experiments were performed to validate the results obtained by one ligand. According to the proposed method, the KD values of inclusion complexes regardless of any stoichiometric relation of host and guest can be obtained.

  8. Environmental and human safety of major surfactants. Volume 1. Anionic surfactants. Part 1. Linear alkylbenzene sulfonates. Final report

    SciTech Connect

    Not Available

    1991-02-01

    The report discusses critical reviews of published literature and unpublished company data on major surfactants. Part 1 of Vol. 1 discusses the chemistry, biodegradation, environmental effects and safety and human safety of linear alkylbenzene sulfonates. The information presented updates and supplements similar data included in two predecessor studies, Human Safety and Environmental Aspects of Major Surfactants (1977) NTIS Accession Number PB-301193 and Human and Environmental Aspects of Major Surfactants (Supplement) (1981) NTIS Accession Number PB-81-182453.

  9. Sulphonated cobalt phthalocyanine-MCM-41: an active photocatalyst for degradation of 2,4-dichlorophenol.

    PubMed

    Zanjanchi, M A; Ebrahimian, A; Arvand, M

    2010-03-15

    The photocatalytic activity of sulphonated cobalt phthalocyanine immobilized onto MCM-41 was investigated for decomposition of 2,4-dichlorophenol (2,4-DCP) in aqueous solutions. Immobilization of anion sulpho-cobalt phthalocyanine to the walls of MCM-41 was performed by pre-anchorage of 3-(aminopropyl)-triethoxysilane (APTES) onto MCM-41 via post-synthesis method. X-ray diffraction, nitrogen physisorption, diffuse reflectance spectroscopy, energy-dispersive X-ray and FT-IR methods were used to characterize the product. Photocatalytic efficiency of the prepared catalyst for degradation of 2,4-DCP was tested under illumination of UV-A and visible light. The results obtained reveal that the photocatalyst is very active in degradation of 2,4-DCP. The photodegradation process is completed within 3h using a dose of 0.6g/L of the catalyst under UV irradiation. The reactions follow a pseudo-first-order kinetics and the observed rate constant values change with 2,4-DCP concentrations. The reproducibility of the catalyst was tested. The reaction intermediates were identified by gas chromatoghraphy-mass spectrometry (GC-MS) technique.

  10. Lysozyme immobilization via adsorption process using sulphonic acid functionalized silane grafted copolymer.

    PubMed

    Anirudhan, T S; Rauf, Tharun A

    2013-07-01

    A unique silane based adsorbent material, [stearyl alcohol (SA)-grafted-epichlorohydrin (E)]-grafted-aminoproypyl silanetriol (APST) was synthesized and functionalized with sulphonyl groups via sulphonation process [(SA-g-E)-g-APST/SO3H]. The adsorbent material characterization was done by FTIR, XRD, and TGA analysis. Immobilization of protein Lysozyme (LYZ) using batch adsorption process was carried out for studying the protein-particle interaction. The most suitable pH for maximum adsorption was found to be 7.0. Pseudo-second-order kinetic model was found to be the best fit and the adsorption equilibrium was attained within 3h. Studies on diffusion parameters explained that the adsorption mechanism was controlled by film diffusion mode. The adsorption process was then evaluated using the various isotherm models and the Sips isotherm model proved to be the best fit with a maximum adsorption capacity of 37.68 mg/g. The isotherm favorability of the adsorption process was calculated by calculating the separation factor (R(L)) and the values confirmed the favorability of the adsorption process. Studies on adsorption percentage with respect to temperature and thermodynamic studies revealed that adsorption process is exothermic, spontaneous with maximum entropy. Batch adsorption/desorption studies in acidic medium, for over six cycles showed the repeatability and regeneration capability of the adsorbent material (SA-g-E)-g-APST/SO3H.

  11. Cell uptake, distribution and response to aluminium chloro sulphonated phthalocyanine, a potential anti-tumour photosensitizer.

    PubMed Central

    Chan, W. S.; Svensen, R.; Phillips, D.; Hart, I. R.

    1986-01-01

    The uptake, retention and effects of aluminium chloro sulphonated phthalocyanine (AlSPc) were measured in two cell lines, UV-2237 a murine fibrosarcoma and the non-tumorigenic NIH/3T3 fibroblast line. The behaviour of cells treated with AlSPc was compared with that of those treated with haematoporphyrin derivative (HpD), a photosensitizer often used in photodynamic therapy (PDT) of cancer. AlSPc absorbs light strongly in the red region, is taken up by cells in a dose dependent fashion and is retained in vitro over a period of days (5 days after exposure greater than 40% remains cell-associated versus less than 25% of HpD). Additionally AlSPc was less cytotoxic to cells, maintained in darkness or exposed to room light, compared to HpD (100% viability versus 0% viability 3 days after 60 min exposure to room light). However red light (approximately 600-700 nm) caused greater toxicity in AlSPc-treated cells (100%) than in similarly exposed HpD-treated cells (less than 60%). No significant differences were detected between the responses of the fibrosarcoma and the fibroblast cell lines. These characteristics of AlSPc suggest that it may prove to be a useful photosensitizer for PDT of cancer and this possibility is discussed. Images Figure 4 PMID:2937437

  12. Charge transport and magnetic properties in polyaniline doped with methane sulphonic acidand polyaniline-polyurethane blend

    NASA Astrophysics Data System (ADS)

    Sanjai, B.; Raghunathan, Anasuya; Natarajan, T. S.; Rangarajan, G.; Thomas, Soloman; Prabhakaran, P. V.; Venkatachalam, S.

    1997-04-01

    Charge transport in polyaniline protonated fully with methane sulphonic acid (MSA) and polyaniline (MSA)-polyurethane [PANI(MSA)-PU] blend has been investigated through measurements of temperature (T) and electric field (E) dependence of conductivity (σ), temperature dependence of thermoelectric power and magnetic susceptibility and electron spin resonance at room temperature. PANI(MSA) exhibits a three-dimensional variable-range hopping (VRH) type of conduction, which is not the case with HCl-doped PANI and the electric field dependence of its conductivity is also consistent with VRH behavior. The thermopower in PANI(MSA) shows metallic behavior. The blend follows a one-dimensional VRH type of conduction and the electric field dependence of its conductivity exhibits the Poole-Frenkel effect. The temperature-dependent magnetic susceptibility measurements indicate the presence of Pauli and Curie spins in both the samples. From electron spin resonance measurements the percentage of Lorentzian and Gaussian spins have been estimated. In PANI-MSA a larger number of spins are found to be delocalized. The conduction mechanism in PANI-PU blend is discussed in comparison to other commercial conducting polymer blends.

  13. Magnetic resonance and electrical properties of p-toluene sulphonic acid doped polyaniline

    NASA Astrophysics Data System (ADS)

    Arora, Manju; Arya, S. K.; Barala, Sunil Kumar; Saini, Parveen

    2013-06-01

    p-Toluene Sulphonic Acid (PTSA) doped polyaniline (PANI) analogues were synthesized by oxidative chemical polymerization method and characterized by TGA FTIR and EPR spectroscopic techniques. FTIR spectra indicates the formation of PTSA doped PANI and also revealed the dopant ions mediated interactions between polymeric chain through weak hydrogen bonding. TGA plots revealed that there is systematic variation in the weight loss at ˜300 °C from ˜4% to ˜38% with increase in dopant concentration from 0.01 N to 1.0 N. Magnetic resonance spectra of polaron charge carriers exhibit the single Lorentzian line signal with the Dysonian contribution indicating formation of metal-like domains. The polarons are localized in these domains by strong interaction between the neighboring conducting chains, in which the charge is transferred by quasi-three-dimensional (Q3D) delocalized electron. In higher concentration analogue some of polarons merge into diamagnetic bipolarons and this reduces intensity of EPR signal. The electrical conductivity of the 1.0 N PTSA doped sample was ˜4.5 S/cm which satisfies the EMI shielding criteri.

  14. Ethyl methane sulphonate induced genetic variability and heritability in macrosperma and microsperma lentils.

    PubMed

    Rana, Aman; Solanki, I S

    2015-09-01

    Dry and healthy seeds of two lentil cultivars, LH90-54 (macrosperma) and LH89-48 (microsperma) were treated with three doses of ethyl methane sulphonate (0.1, 0.2 and 0.4 %). In both the cultivars, all the M, plants with sufficient seed from each treatment and control were taken to raise independent M2 plant progenies. Wider range of means in both positive and negative directions along with overall positive shift in mean for all the polygenic traits, except pod-initiation height and 100-seed weight, were observed in different treatments in M2 generation. In both the cultivars, medium dose induced highest amount of variation. The estimates of variance, GCV and PCV for different polygenic traits increased significantly over control values in all the treatments of both the cultivars. Higher estimates of heritability and genetic advance in M2 population indicated tremendous scope for the improvement of seed yield and its component traits through selection in the mutagenized material.

  15. Reinforcement of poly ether sulphones (PES) with exfoliated graphene oxide for aerospace applications

    NASA Astrophysics Data System (ADS)

    Balasubramanian, K.

    2012-09-01

    Composite materials have been used for aerospace for some time now and have gained virtually 100% acceptance as the materials of choice. Speciality polymers like poly ether sulphones (PES), poly ether ether ketones(PEEK), poly ether imides (PEI) are highly preferred materials as plastic matrix due to their superior temperature performance, excellent wear & friction resistance, excellent dimensional accuracy, high tensile strength, high modulus, precise machinability and chemical resistance. In recent years nanoadditives like single and multiwall carbon nanotubes, graphenes and graphene oxides(GO) are finding huge market potential in aerospace and automobile industries. But manufacture related factors such as particle/ matrix interphases, surface activation, mixing process, particle agglomeration, particle size and shape may lead to different property effects. In this research GO/PES composites were prepared by high shear melt blending technique. GO monolayers were exfoliated from natural graphite flake and dispersed homogeneously in PES matrix for the GO content ranging between 0.5 to 2.0 volume percentage with a high shear twin screw batch mixer. These melt blended nanocomposites were injection moulded for mechanical property validation of tensile strength, flexural modulus and impact resistance. Addition of 0.5 volume percentage of GO enhanced the tensile strength and flexural modulus by 40% and 90% respectively. The results show that addition of GO to PES increase mechanical properties due to the formation of continuous network, good dispersion and strong interfacial interactions. The strong interfacial interactions were accounted for the increase in glass transition temperature. Also there was a significant improvement in the impact resistance of the PES/ GO nanocomposite. The injection moulded samples were tested for stealth performance by measuring the electromagnetic shielding property.

  16. Modeling the Conformation-Specific Infrared Spectra of N-Alkylbenzenes

    NASA Astrophysics Data System (ADS)

    Tabor, Daniel P.; Sibert, Edwin; Hewett, Daniel M.; Korn, Joseph A.; Zwier, Timothy S.

    2016-06-01

    Conformation-specific UV-IR double resonance spectra are presented for n-alkylbenzenes. With the aid of a local mode Hamiltonian that includes the effects of stretch-bend Fermi coupling, the spectra of ethyl, n-propyl, and n-butylbenzene are assigned to individual conformers. These molecules allow for further development of the work on a first principles method for calculating alkyl stretch spectra. Due to the consistency of the anharmonic couplings from conformer to conformer, construction of the model Hamiltonian for a given conformer only requires a harmonic frequency calculation at the conformer's minimum geometry as an input. The model Hamiltonian can be parameterized with either density functional theory or MP2 electronic structure calculations. The relative strengths and weaknesses of these methods are evaluated, including their predictions of the relative energetics of the conformers. Finally, the IR spectra for conformers that have the alkyl chain bend back and interact with the π cloud of the benzene ring are modeled.

  17. Calcium carbonate phase transformations during the carbonation reaction of calcium heavy alkylbenzene sulfonate overbased nanodetergents preparation.

    PubMed

    Chen, Zhaocong; Xiao, Shan; Chen, Feng; Chen, Dongzhong; Fang, Jianglin; Zhao, Min

    2011-07-01

    The preparation and application of overbased nanodetergents with excess alkaline calcium carbonate is a good example of nanotechnology in practice. The phase transformation of calcium carbonate is of extensive concern since CaCO(3) serves both as an important industrial filling material and as the most abundant biomineral in nature. Industrially valuable overbased nanodetergents have been prepared based on calcium salts of heavy alkylbenzene sulfonate by a one-step process under ambient pressure, the carbonation reaction has been monitored by the instantaneous temperature changes and total base number (TBN). A number of analytical techniques such as TGA, DLS, SLS, TEM, FTIR, and XRD have been utilized to explore the carbonation reaction process and phase transformation mechanism of calcium carbonate. An enhanced understanding on the phase transformation of calcium carbonate involved in calcium sulfonate nanodetergents has been achieved and it has been unambiguously demonstrated that amorphous calcium carbonate (ACC) transforms into the vaterite polymorph rather than calcite, which would be of crucial importance for the preparation and quality control of lubricant additives and greases. Our results also show that a certain amount of residual Ca(OH)(2) prevents the phase transformation from ACC to crystalline polymorphs. Moreover, a vaterite nanodetergent has been prepared for the first time with low viscosity, high base number, and uniform particle size, nevertheless a notable improvement on its thermal stability is required for potential applications.

  18. Tracking anthropogenic influences on the continental shelf of China with sedimentary linear alkylbenzenes (LABs).

    PubMed

    Wei, Gao-Ling; Liu, Liang-Ying; Bao, Lian-Jun; Zeng, Eddy Y

    2014-03-15

    Surface sediments collected along the entire continental shelf of China, including Yellow Sea, the East China Sea (ECS) inner shelf and the South China Sea (SCS), were analyzed for linear alkylbenzenes (LABs), from which regional anthropogenic influences on the marine environment were assessed. The occurrence of LABs (5.6-77 ng/g; mean: 25 ng/g; median: 20 ng/g) implied light sewage contamination in coast sediment off China. Specifically, the SCS had higher sedimentary LAB levels than Yellow Sea and the ECS inner shelf, which was mainly related to the intensity of domestic wastewater discharge and marine fishing activities. Values of L/S and C₁₃/C₁₂ (defined in the main text) suggested certain degradation while I/E indicated limited degradation of LABs. Also, additional input sources and congener inter-conversions may have contributed to the inconsistent results for degradation of LABs in offshore sediments. Atmospheric inputs and wastewater discharge from marine fishing vessels predominantly contributed to sedimentary LABs in Yellow Sea and the SCS, while riverine input was mainly responsible for LABs along the ECS inner shelf.

  19. LAS homolog distribution shift during wastewater treatment and composting ecological implications

    SciTech Connect

    Prats, D.; Ruiz, F.; Vazquez, B.; Zarzo, D. . Div. Chemical Engineering); Berna, J.L.; Moreno, A. )

    1993-09-01

    The behavior of LAS (linear alkylbenzene sulfonate) in different environmental compartments was studied through wastewater treatment process steps in sewage treatment plants of Alicante and Benidorm (activated sludge type) as well as in Guardamar (lagoons). The fate of LAS, using a specific HPLC method, was monitored during treatment sludge compostage and soil amendment operations. Finally, the marine sediments close to a submarine wastewater sewer outfall were analyzed. The results show significant differences between distribution of LAS homologs in water and solids (sludges, sediments, and soils), as compared to the original distribution in detergent formulations, yielding a lower LAS average molecular weight in water samples. The change observed in the homolog distribution of LAS implies a reduction in the toxicity to Daphnia, because a lower average molecular weight of LAS is less toxic.

  20. Axial and equatorial conformations of penicillins, their sulphoxides and sulphones: the role of NH⋯S and CH⋯O hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Nangia, Ashwini; Desiraju, Gautam R.

    1999-01-01

    The thiazolidine ring of the penam skeleton exists in two distinct conformations wherein the 3α-CO 2H group is in the axial or equatorial orientation. Crystal structure data have been retrieved from the Cambridge Structural Database (CSD) on 49 penams. These include 30 penicillins, 10 sulphoxides and 9 sulphones. Of the penicillins, 24 are in the axial conformation and 6 are in the equatorial conformation. The 19 sulphoxides and sulphones are exclusively in the equatorial conformation. It is suggested that the axial conformation in penicillins is stabilised by intramolecular NH⋯S and CH⋯O hydrogen bonds, jointly worth about 3 kcal/mol. Calculations show that the sulphoxides and sulphones do not adopt the axial conformation because of a repulsive C⋯O interaction between the gem-dimethyl group in the C2 position and the sulphoxide/sulphone O-atom. The pharmocophore groups of the penicillin antibiotics and the sulphoxides/sulphones lie in distinct, well-defined regions and this suggests that the biologically active conformation is the one with the axially oriented 3α-CO 2H group.

  1. Different alkyl dimethacrylate mediated stearyl methacrylate monoliths for improving separation efficiency of typical alkylbenzenes and proteins.

    PubMed

    Xu, Zhendong; Yang, Limin; Wang, Qiuquan

    2009-04-10

    Monoliths were prepared in 530 microm I.D. fused silica capillaries via in situ copolymerization of stearyl methacrylate (SMA) with a dimethacrylate cross-linker in the presence of a binary porogenic solvent containing tert.-butanol and 1,4-butanediol. Alkyl dimethacrylate cross-linkers other than the monomer were used to tune the monolith properties, and, as a result, an increase in the hydrophobicity of the final monoliths (the methylene selectivity [Formula: see text] increased from 1.396 to 1.475) was observed through an increase in the molecular chain length between two methacrylate units from the 0.360 nm of ethylene glycol dimethacrylate to the 1.241 nm of 1.9-nonanediol dimethacrylate. Moreover, the hydrophobicity of the final monoliths was also greatly affected by the methyl group branch in the cross-linkers, among which the 2-methyl-1,8-octanediol dimethacrylate (2-Me-1,8-ODDMA) mediated monolith exhibited the highest hydrophobicity ( [Formula: see text] was 1.482) and fastest mass transfer kinetics (C-term was 9.14 ms). Besides the effective separation of six model proteins, the poly(SMA-co-2-Me-1,8-ODDMA) monolith also showed an improved performance in the separation of alkylbenzenes. The theoretical plate numbers reached 83000plates/m and 52000 plates/m for thiourea (nonretained compound) and butylbenzene (retained compound), respectively, when using acetonitrile-water (70:30, v/v) as the mobile phase at a typical linear velocity of 1mm/s. This improved performance towards small molecules was attributed to an increased mesopore proportion in the monolith and the faster dynamic process of mass transfer arising from novel tailoring of the monolith by choosing a suitable monomer/cross-linker pair.

  2. Where's the Bend? Locating the First Folded Structure in Straight Chain Alkylbenzenes in a Supersonic Jet Expansion

    NASA Astrophysics Data System (ADS)

    Hewett, Daniel M.; Bocklitz, Sebastian; Suhm, Martin A.; Zwier, Timothy S.

    2016-06-01

    Alkylbenzenes make up 20-30% of petroleum fuels and are important intermediates in combustion. In gasoline, these alkyl chains are relatively short, but extend to 20 or more carbons in length in diesel fuels. While one tends to think of these chains as extending out away from the phenyl ring in an all-trans configuration, dispersive interactions between segments of the alkyl chain and between the alkyl chain and the ring will stabilize more compact geometries in which the alkyl chain folds back on itself and extends over the aromatic π cloud. This talk seeks to answer the following question: How long must the alkyl chain be before it starts to fold back over itself? Studies of the pure n-alkanes by the Suhm group have shown the turn to favorably occur for a chain about 17 carbon atoms in length. The studies presented here focus on the affect the aromatic ring has on when this turn becomes favorable. Jet-cooled laser-induced fluorescence excitation and single-conformation IR spectra have been recorded in the alkyl CH stretch region for a series of alkylbenzenes with chain lengths ranging from two to ten carbon atoms. We show, through a combination of experiment, high level calculation, and theoretical modeling, that conformations begin to form that fold back over the aromatic ring at about n=8.

  3. Synthetic detergents induced-biochemical and histological changes in skin of guinea pigs.

    PubMed

    Agarwal, C; Mathur, A K; Gupta, B N; Singh, A; Shanker, R

    1990-06-01

    The linear alkylbenzene sulphonate (LAS) based synthetic detergents-induced decrease in lipid peroxydation and increase in histamine content in exposed skin of guinea pigs in a dose-dependent manner. Histopathological alterations of exposed skin included moderate degree of hyperkeratinization at lower concentration but necrosis, scarring, sloughing as well as discontinuity of epidermis at higher concentrations. The results shows that the contact of skin with detergents causes dermal toxicity.

  4. Comparison of aluminum sulphonated phthalocyanine with 5-aminolaevulinic-acid-induced protoporphyrin IX: tissue distributions, photodamage, and photodegradation

    NASA Astrophysics Data System (ADS)

    MacRobert, Alexander J.; Bedwell, Joanne; Loh, C. S.; Chatlani, P. T.; Bown, Stephen G.

    1993-06-01

    Fluorescence spectroscopic studies have been carried out on tissue sensitization by Aluminium Sulphonated Phthalocyanine (AlSPc) and endogenous Protoporphyrin IX induced by administration of exogenous 5-aminolaevulinic acid (ALA). A charge-coupled device (CCD) imaging system has been used to obtain quantitative fluorescence distributions of sensitization in frozen sections taken from rat tumors together with normal adjacent tissues. Using ALA, specific porphyrin sensitization of malignant epithelium is observed with much less sensitization present in connective tissue. Photodegradation of AlSPc and PPIX was studied by monitoring of fluorescence bleaching: in normal rat colon there is a significant reduction in AlSPc fluorescence at the edge of the photonecrosed zone which suggests that photodegradation may provide a means of diagnosing the extent of tissue damage. ALA- induced PPIX fluorescence is also observed to bleach in colon simultaneously with an increase in fluorescence emission near 675 nm which we attribute to a photoprotoporphyrin degradation product.

  5. Curcumin inhibits trinitrobenzene sulphonic acid-induced colitis in rats by activation of peroxisome proliferator-activated receptor gamma.

    PubMed

    Zhang, Ming; Deng, Changsheng; Zheng, Jiaju; Xia, Jian; Sheng, Dan

    2006-08-01

    Curcumin is a widely used spice with anti-inflammatory and anti-cancer properties. It has been reported that curcumin held therapeutic effects on experimental colitis by inhibition of nuclear factor kappa B (NF-kappaB). The peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor with anti-tumor and anti-inflammatory effects and its activation may inhibit the nuclear translocation of NF-kappaB. Several studies have shown that PPARgamma ligands had an important therapeutic effect in colitis. However there is no report about the alteration of PPARgamma in trinitrobenzene sulphonic acid (TNBS)-induced colitis treated with curcumin. In this study, we administered curcumin (30 mg/kg/day) by intraperitoneal injection immediately after colitis was induced and the injection lasted for two weeks. have evaluated the effects of curcumin on the colitis induced by trinitrobenzene sulphonic acid (TNBS). Curcumin (30 mg/kg d) was administered by intraperitoneal just after colitis was induced and lasted for two weeks. Therapeutic effects of dexamethasone (Dex, 2 mg/kg d) alone and the combined effects of curcumin+Dex were also examined. We found that curcumin improved long-term survival rate of disease-bearing rats, promoted rat body weight recovery, and decreased macroscopic scores of the colitis. The expression levels of PPARgamma, 15-deoxy-D12,14-prostaglandin J(2) (15d-PGJ(2)) and prostaglandin E(2) (PGE(2)) were all increased, but the expression level of cyclooxygenase-2 (COX-2) was decreased in rats after administration of curcumin. Treatment with Dex improved PPARgamma expression and inhibited the expression of COX-2, 15d-PGJ(2) and PGE(2). Combined effects of curcumin+Dex were similar to that of Dex. In summary, curcumin showed therapeutic effects on TNBS-induced colitis and the mechanisms by which curcumin exerts its effects may involve activation of PPARgamma and its ligands.

  6. Depositional history of sedimentary linear alkylbenzenes (LABs) in a large South American industrial coastal area (Santos Estuary, Southeastern Brazil).

    PubMed

    Martins, César C; Bícego, Márcia C; Mahiques, Michel M; Figueira, Rubens C L; Tessler, Moyses G; Montone, Rosalinda C

    2010-11-01

    This paper reports the reconstruction of the contamination history of a large South American industrial coastal area (Santos Estuary, Brazil) using linear alkylbenzenes (LABs). Three sediment cores were dated by (137)Cs. Concentrations in surficial layers were comparable to the midrange concentrations reported for coastal sediments worldwide. LAB concentrations increased towards the surface, indicating increased waste discharges into the estuary in recent decades. The highest concentration values occurred in the early 1970s, a time of intense industrial activity and marked population growth. The decreased LAB concentration, in the late 1970s was assumed to be the result of the world oil crisis. Treatment of industrial effluents, which began in 1984, was represented by decreased LAB levels. Microbial degradation of LABs may be more intense in the industrial area sediments. The results show that industrial and domestic waste discharges are a historical problem in the area.

  7. Linear alkylbenzene sulfonate tolerance in bacteria isolated from sediment of tropical water bodies polluted with detergents.

    PubMed

    Eniola, Kehinde I T; Olayemi, Albert B

    2008-12-01

    The discharge of untreated detergent-bearing waste introduces linear alklcylbenzene sulfonates (LAS) to the aquatic environment. The surfactant persists in some streams and rivers in Nigeria, some is adsorbed to suspended materials and end in the sediment of the receiving water bodies. In this study, bacteria isolated from sediments of some tropical detergent-effluent-polluted streams were tested for tolerance to LAS using the media dilution technique. LAS-tolerance was indicated by growth of the bacteria in the presence of the surfactant. The pH, concentrations of surfactant, population of heterotrophic bacteria and population of LAS-tolerant bacteria in the sediments were determined. A direct relationship (r = 0.9124) was found between the alkaline conditions (pH= 8.2-12.0) and high surfactant concentrations (45-132 mg/g) in the sediment. The sediments harboured a high population and a wide variety of bacteria; the populations of viable heterotrophic bacteria (VHB: 2.9 x 10(5) to 1.2 x 10(7) cfu/g) and LAS tolerant bacteria (LTB: 1.5 x 10(4) to 1.2 x 10(6) cfu/g) had a direct relationship (r = 0.9500). An inverse relationship resulted between each of them and the concentration of surfactant in the sediment, r(VHB/LAS) = -0.9303 and r(LTB/LAS) = -0.9143, respectively. Twelve bacteria species were isolated from the sediment: Alcaligenes odorans, Bacillus subtilis, Burkholderia cepacia, Citrobacter freundii, Citrobacter diversus, Escherichia coli, Micrococcus luteus, Micrococcus albus, Pseudomonas putida, Pseudomonas stutzeri, Staphylococcus aureus and Streptococcusfaecalis. Most of them were adapted to the surfactant with their maximum acceptable concentrations ranging between 0.03 and >1.0% (w/v). The sediments could serve as source of adapted organisms which can be used in bio-treatment of LAS-bearing waste.

  8. Evaluation of ultraviolet spectrophotometry for simultaneous analysis of alkylbenzenes, alkylnaphthalenes, alkylanthracenes/phenanthrenes and total aromatics in mid-distillate fuels

    NASA Technical Reports Server (NTRS)

    Kim, W. S.; Seng, G. T.

    1982-01-01

    A rapid ultraviolet spectrophotometric method for the simultaneous determination of aromatics in middistillate fuels was developed and evaluated. In this method, alkylbenzenes, alkylnaphthalenes, alkylanthracenes/phenanthracenes and total aromatics were determined from ultraviolet spectra of the fuels. The accuracy and precision were determined using simulated standard fuels with known compositions. The total aromatics fraction accuracy was 5% for a Jet A type fuel and 0.6% for a broadened properties jet turbine type fuel. Precision, expressed as relative standard deviations, ranged from 2.9% for the alkylanthracenes/phenanthrenes to 15.3% for the alkylbenzenes. The accuracy, however, was less for actual fuel samples when compared to the results obtained by a mass spectrometric method. In addition, the ASTM D-1840 method for naphthalenes by ultraviolet spectroscopy was evaluated.

  9. Effects of process stability on anaerobic biodegradation of LAS in UASB reactors.

    PubMed

    Løbner, Trine; Toräng, Lars; Batstone, Damien John; Schmidt, Jens Ejbye; Angelidaki, Irini

    2005-03-30

    Anaerobic biodegradation of linear alkylbenzene sulfonates (LAS) was studied in upflow anaerobic sludge blanket (UASB) reactors operated under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. LAS C12 concentration in the influents was 10 mg.L(-1), and the hydraulic retention time in the reactors was 2 days. Adsorption of LAS C12 was assessed in an autoclaved control reactor and ceased after 115 days. The reactors were operated for a minimum of 267 days; 40-80% removal of LAS C12 was observed. A temperature reduction from 55 degrees C to 32 degrees C for 30 h resulted in process imbalance as indicated by increase of volatile fatty acids (VFA). The imbalance was much more intense in the LAS amended reactor compared with an unamended reactor. At the same time, the process imbalance resulted in discontinued LAS removal. This finding indicates that process stability is a key factor in anaerobic biological removal of LAS. After a recovery period, the removal of LAS resumed, providing evidence of biological anaerobic LAS degradation. The removal remained constant until termination of experiments in the reactor. Biodegradation of LAS in the mesophilic reactor was at the same level as in the thermophilic reactor under stable conditions.

  10. Acute toxicity of sodium formononetin-3'-sulphonate (Sul-F) in Sprague-Dawley rats and Beagle dogs.

    PubMed

    Li, Guisheng; Yang, Menglin; Hao, Xinmiao; Li, Chunmei; Gao, Yonglin; Tao, Jun

    2015-11-01

    Sodium formononetin-3'-sulphonate (Sul-F, C16H12O7SNa), a water-soluble derivate of formononetin, provided significant neuroprotective and cardioprotective effects in vitro and in vivo. The aim of this study was to evaluate acute toxicity of Sul-F after intravenous administration in rats and dogs. Animals were intravenously administered Sul-F at the maximum dosage of 2000 mg/kg and 1000 mg/kg in rats and dogs, respectively. After treatment, rats and dogs were monitored for 14 days. Body weight, clinical signs, the hematological and biochemical findings, and pathological examination were performed. The results showed that no Sul-F related clinical signs of toxicity or mortality were observed in rats. Of note, the transient vomiting was found in dogs after Sul-F administration 15-20 min. In addition, a white crystal, non-metabolic Sul-F, was found after urine volatilization in Sul-F treated animals (rats and dogs). However, neither biochemical findings nor histopathological changes due to Sul-F treatment were found in tests. In summary, the present study results provided practical guidance for selecting a safe dosage for Sul-F further studies and clinical trials in the future.

  11. Novel spectrophotometric method for determination of some macrolide antibiotics in pharmaceutical formulations using 1,2-naphthoquinone-4-sulphonate

    NASA Astrophysics Data System (ADS)

    Ashour, Safwan; Bayram, Roula

    2012-12-01

    New, simple and rapid spectrophotometric method has been developed and validated for the assay of two macrolide drugs, azithromycin (AZT) and erythromycin (ERY) in pure and pharmaceutical formulations. The proposed method was based on the reaction of AZT and ERY with sodium 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline medium at 25 °C to form an orange-colored product of maximum absorption peak at 452 nm. All variables were studied to optimize the reaction conditions and the reaction mechanism was postulated. Beer's law was obeyed in the concentration range 1.5-33.0 and 0.92-8.0 μg mL-1 with limit of detection values of 0.026 and 0.063 μg mL-1 for AZT and ERY, respectively. The calculated molar absorptivity values are 4.3 × 104 and 12.3 × 104 L mol-1 cm-1 for AZT and ERY, respectively. The proposed methods were successfully applied to the determination of AZT and ERY in formulations and the results tallied well with the label claim. The results were statistically compared with those of an official method by applying the Student's t-test and F-test. No interference was observed from the concomitant substances normally added to preparations.

  12. A 90-day subchronic toxicity study with sodium formononetin-3'-sulphonate (Sul-F) delivered to dogs via intravenous administration.

    PubMed

    Li, Chunmei; Li, Guisheng; Gao, Yonglin; Sun, Chengfeng; Wang, Xiaoyan

    2016-06-01

    Sodium formononetin-3'-sulphonate (Sul-F) is a water-soluble derivate of formononetin, and an increasing number of studies have shown that Sul-F not only possesses favorable water solubility but also exhibits good lipid-lowering and bioactivities. In the current study, the toxicity of Sul-F was evaluated in dogs after 90-day intravenous infusion. Dogs were treated with Sul-F at dose of 0, 33.3, 100, and 300 mg/kg, and observed for 90-day followed by 28-day recovery period. Weekly measurement of body weight, temperature and food consumption were conducted. Ophthalmoscopy, ECG examination, urinalysis, serum biochemistry and hematology examination were performed at pre-test, on days 45 and 90, and following by 28-day recovery period. Histological examination was performed on day 90 and 28-day recovery period. No mortality, ophthalmic abnormalities or treatment-related findings in body weight, clinical chemistry, hematology, and histopathological examination were detected. However, a white crystal (non-metabolic Sul-F), transient vomiting and recoverable vascular stimulation were observed in 300 mg/kg/day Sul-F treated dogs. Under the conditions, the no-observed-adverse-effect-level (NOAEL) for Sul-F was 100 mg/kg in dogs.

  13. Doping effect of dodecyl benzene sulphonic acid in poly(3-hexylthiophene)-P3HT-films

    NASA Astrophysics Data System (ADS)

    Alveroglu, Esra

    2015-04-01

    We demonstrated that how dodecyl benzene sulphonic acid (DBSA) as a small-molecular dopant, affects the spectroscopic, electronic and structural properties of poly(3-hexylthiophene) (P3HT). The DBSA volume ratio was varied from 0.001 μL to 30 μL per 1 mL P3HT solvent in p-xylene. DBSA doping reaction was confirmed by the emerging huge absorption peak at the wavelength of ∼800 nm while the ionization potential and nanostructure of P3HT films were highly affected. Additionally, conductivity of P3HT films increased nearly 1000 times at 30 μL DBSA. The crystallinity, as well as the conductivity and the UV-Vis absorption changed with the presence of P3HT. P3HT grain sized crystals seems to be disturbed by the addition of DBSA, but still remained even more DBSA was introduced. DBSA doping has interesting properties when incorporated in OFTs, OPVs and bioelectronics applications, so addition of DBSA can open new pathways for structural, spectroscopic and electronic control of organic semiconductor's blends.

  14. Effects of dosmalfate, a new cytoprotective agent, on acute and chronic trinitrobenzene sulphonic acid-induced colitis in rats.

    PubMed

    Villegas, Isabel; La Casa, Carmen; Orjales, Aurelio; Alarcón de la Lastra, Catalina

    2003-01-24

    Activated neutrophils and proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) are clearly involved in the pathogenesis of bowel disease. Increased expression of epidermal growth factor-receptor (EGF receptor) has been reported for the colon mucosa surrounding areas of ulceration, suggesting a pivotal role in mucosal defence and repair. In this study, we examined the effects of dosmalfate, a new flavonoid derivative compound (diosmin heptakis) with antioxidant and cytoprotective properties, on acute and chronic experimental trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. The inflammation response was assessed by neutrophil infiltration as evaluated by histology and myeloperoxidase activity. Mucosal TNF-alpha production and histological analysis of the lesions was also carried out. In addition, we studied the expression of the EGF receptor inmunohistochemically during the healing of TNBS-induced chronic colitis. A 2-day treatment with 400 or 800 mg/kg of dosmalfate ameliorated the colon damage score and the incidence of adhesions. It also significantly (P<0.05) decreased myeloperoxidase activity and colonic mucosal production of TNF-alpha. Chronic treatment (14 days) with 800 mg/kg/day of dosmalfate also had significant protective effects on TNBS-induced colitis which were reflected by significant attenuation (P<0.05) of the damage score while the inflammatory indicators were not improved. The chronic beneficial effect of dosmalfate was apparently related to the enhancement of EGF receptor expression. These findings confirm the protective effects of dosmalfate in acute and chronic experimental colitis.

  15. Natural attenuation of volatile organic compounds (VOCs) in the leachate plume of a municipal landfill: Using alkylbenzenes as process probes

    USGS Publications Warehouse

    Eganhouse, R.P.; Cozzarelli, I.M.; Scholl, M.A.; Matthews, L.L.

    2001-01-01

    More than 70 individual VOCs were identified in the leachate plume of a closed municipal landfill. Concentrations were low when compared with data published for other landfills, and total VOCs accounted for less than 0.1% of the total dissolved organic carbon. The VOC concentrations in the core of the anoxic leachate plume are variable, but in all cases they were found to be near or below detection limits within 200 m of the landfall. In contrast to the VOCs, the distributions of chloride ion, a conservative tracer, and nonvolatile dissolved organic carbon, indicate little dilution over the same distance. Thus, natural attentuation processes are effectively limiting migration of the VOC plume. The distribution of C2-3-benzenes, paired on the basis of their octanol-water partition coefficients and Henry's law constants, were systematically evaluated to assess the relative importance of volatilization, sorption, and biodegradation as attenuation mechanisms. Based on our data, biodegradation appears to be the process primarily responsible for the observed attenuation of VOCs at this site. We believe that the alkylbenzenes are powerful process probes that can and should be exploited in studies of natural attenuation in contaminated ground water systems.

  16. Anaerobic Oxidation of o-Xylene, m-Xylene, and Homologous Alkylbenzenes by New Types of Sulfate-Reducing Bacteria

    PubMed Central

    Harms, Gerda; Zengler, Karsten; Rabus, Ralf; Aeckersberg, Frank; Minz, Dror; Rosselló-Mora, Ramon; Widdel, Friedrich

    1999-01-01

    Various alkylbenzenes were depleted during growth of an anaerobic, sulfate-reducing enrichment culture with crude oil as the only source of organic substrates. From this culture, two new types of mesophilic, rod-shaped sulfate-reducing bacteria, strains oXyS1 and mXyS1, were isolated with o-xylene and m-xylene, respectively, as organic substrates. Sequence analyses of 16S rRNA genes revealed that the isolates affiliated with known completely oxidizing sulfate-reducing bacteria of the δ subclass of the class Proteobacteria. Strain oXyS1 showed the highest similarities to Desulfobacterium cetonicum and Desulfosarcina variabilis (similarity values, 98.4 and 98.7%, respectively). Strain mXyS1 was less closely related to known species, the closest relative being Desulfococcus multivorans (similarity value, 86.9%). Complete mineralization of o-xylene and m-xylene was demonstrated in quantitative growth experiments. Strain oXyS1 was able to utilize toluene, o-ethyltoluene, benzoate, and o-methylbenzoate in addition to o-xylene. Strain mXyS1 oxidized toluene, m-ethyltoluene, m-isoproyltoluene, benzoate, and m-methylbenzoate in addition to m-xylene. Strain oXyS1 did not utilize m-alkyltoluenes, whereas strain mXyS1 did not utilize o-alkyltoluenes. Like the enrichment culture, both isolates grew anaerobically on crude oil with concomitant reduction of sulfate to sulfide. PMID:10049854

  17. Novel spectrophotometric method for determination of cinacalcet hydrochloride in its tablets via derivatization with 1,2-naphthoquinone-4-sulphonate

    PubMed Central

    2012-01-01

    This study represents the first report on the development of a novel spectrophotometric method for determination of cinacalcet hydrochloride (CIN) in its tablet dosage forms. Studies were carried out to investigate the reaction between CIN and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 8.5), an orange red-colored product exhibiting maximum absorption peak (λmax) at 490 nm was produced. The stoichiometry and kinetic of the reaction were investigated and the reaction mechanism was postulated. This color-developing reaction was employed in the development of a simple and rapid visible-spectrophotometric method for determination of CIN in its tablets. Under the optimized reaction conditions, Beer's law correlating the absorbance with CIN concentration was obeyed in the range of 3 - 100 μg/ml with good correlation coefficient (0.9993). The molar absorptivity (ε) was 4.2 × 105 l/mol/cm. The limits of detection and quantification were 1.9 and 5.7 μg/ml, respectively. The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%. No interference was observed from the excipients that are present in the tablets. The proposed method was applied successfully for the determination of CIN in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.80 - 102.23 ± 1.27 - 1.62%. The results were compared favorably with those of a reference pre-validated method. The method is practical and valuable in terms of its routine application in quality control laboratories. PMID:22305461

  18. Magnetorheological properties of sodium sulphonate capped electrolytic iron based MR fluid: a comparison with CI based MR fluid

    NASA Astrophysics Data System (ADS)

    Vinod, Sithara; John, Reji; Philip, John

    2017-02-01

    Magnetorheological fluids have numerous engineering applications due to their interesting field assisted rheological behavior. Most commonly used dispersed phase in MR fluids is carbonyl iron (CI). The relatively high cost of CI warrants the need to develop cheaper alternatives to CI, without compromising rheological properties. With the above goal in mind, we have synthesized sodium sulphonate capped electrolytic iron based MR fluid and studied their magnetorheological properties. The results are compared with that of CI based MR fluid. EI and CI particles of average particle size of ∼10 μm with fumed silica particles additives are used in the present study. The dynamic yield stress for EI and CI based MR fluid were found to vary with field strength with an exponent of roughly 1.2 and 1.24, respectively. The slightly lower static and dynamic yield stress values of EI based MR fluid is attributed to the lower magnetization and polydispersity values. The dynamic yield stress showed a decrease of 18.73% and 61.8% for field strengths of 177 mT and 531 mT, respectively as the temperature was increased from 293 to 323 K. The optorheological studies showed a peak in the loss moduli, close to the crossover point of the storage and loss moduli, due to freely moving large sized aggregates along the shear direction that are dislodged from the rheometer plates at higher strains. Our results suggests that EI based MR fluids have magnetorheological behavior comparable to that of CI based MR fluids. As EI is much cheaper than CI, our findings will have important commercial implications in producing cost effective EI based MR fluids.

  19. Inhibition of biogas production by alkyl benzene sulfonates (LAS) in a screening test for anaerobic biodegradability.

    PubMed

    Garcia, M Teresa; Campos, Encarna; Dalmau, Manel; Illán, Patricia; Sánchez-Leal, Joaquin

    2006-02-01

    The effect of the inoculum source on the digestion of linear alkylbenzene sulfonates (LAS) under anaerobic conditions has been investigated. The potential for primary and ultimate LAS biodegradation of anaerobic sludge samples obtained from wastewater treatment plants (WWTPs) of different geographical locations was studied applying a batch test system. It was found that only 4-22% of the LAS added to the batch anaerobic digesters was primarily transformed suggesting a poor primary degradation of the LAS molecule in anaerobic discontinuous systems. Regarding ultimate biodegradation, the addition of LAS to the batch anaerobic digesters caused a reduction on the extent of biogas production. Significant differences in the inhibition extent of the biogas production were observed (4-26%) depending on the sludge used as inoculum. Effect of the surfactant on the anaerobic microorganisms was correlated with its concentration in the aqueous phase. Sorption of LAS on anaerobic sludge affects its toxicity by depletion of the available fraction of the surfactant. LAS content on sludge was related to the total amount of calcium and magnesium extractable ions. The presence of divalent cations promote the association of LAS with anaerobic sludge reducing its bioavailability and the extent of its inhibitory effect on the biogas production.

  20. Glucose biosensor based on the immobilization of glucose oxidase on electrochemically synthesized polypyrrole-poly(vinyl sulphonate) composite film by cross-linking with glutaraldehyde.

    PubMed

    Colak, Ozlem; Yaşar, Ahmet; Cete, Servet; Arslan, Fatma

    2012-10-01

    In this study, a novel amperometric glucose biosensor was developed by immobilizing glucose oxidase (GOX) by cross-linking via glutaraldehyde on electrochemically polymerized polypyrrole-poly(vinyl sulphonate) (PPy-PVS) films on the surface of a platinum (Pt) electrode. Electropolymerization of pyrrole and poly(vinyl sulphonate) on the Pt surface was carried out with an electrochemical cell containing pyrrole and poly(vinyl sulphonate) by cyclic voltammetry between -1.0 and + 2.0 V (vs.Ag/AgCl) at a scan rate of 50 mV/s upon the Pt electrode. The amperometric determination was based on the electrochemical detection of H(2)O(2) generated in enzymatic reaction of glucose. Determination of glucose was carried out by the oxidation of enzymatically produced H(2)O(2) at 0.4 V vs. Ag/AgCl. The effects of pH and temperature were investigated and optimum parameters were found to be 7.5 and 65°C, respectively. The effect of working potential was investigated and optimum potential was determined to be 0.4 V. The operational stability of the enzyme electrode was also studied. The response of the PPy/PVS-GOX glucose biosensor exhibited good reproducibility with a relative standard deviation (RSD) of 2.48%. The glucose biosensor retained 63% of initial activity after 93 days when stored in 0.1 M phosphate buffer solution of pH 7.5 at 4°C. With the low operating potential, the biosensor demonstrated little interference from the possible interferants.

  1. Molecular dynamics simulation of diffusion coefficients and structural properties of some alkylbenzenes in supercritical carbon dioxide at infinite dilution

    SciTech Connect

    Wang, Jinyang; Zhong, Haimin; Qiu, Wenda; Chen, Liuping; Feng, Huajie

    2014-03-14

    The binary infinite dilute diffusion coefficients, D{sub 12}{sup ∞}, of some alkylbenzenes (Ph-C{sub n}, from Ph-H to Ph-C{sub 12}) from 313 K to 333 K at 15 MPa in supercritical carbon dioxide (scCO{sub 2}) have been studied by molecular dynamics (MD) simulation. The MD values agree well with the experimental ones, which indicate MD simulation technique is a powerful way to predict and obtain diffusion coefficients of solutes in supercritical fluids. Besides, the local structures of Ph-C{sub n}/CO{sub 2} fluids are further investigated by calculating radial distribution functions and coordination numbers. It qualitatively convinces that the first solvation shell of Ph-C{sub n} in scCO{sub 2} is significantly influenced by the structure of Ph-C{sub n} solute. Meanwhile, the mean end-to-end distance, the mean radius of gyration and dihedral angle distribution are calculated to gain an insight into the structural properties of Ph-C{sub n} in scCO{sub 2}. The abnormal trends of radial distribution functions and coordination numbers can be reasonably explained in term of molecular flexibility. Moreover, the computed results of dihedral angle clarify that flexibility of long-chain Ph-C{sub n} is the result of internal rotation of C-C single bond (σ{sub c-c}) in alkyl chain. It is interesting that compared with n-alkane, because of the existence of benzene ring, the flexibility of alkyl chain in Ph-C{sub n} with same carbon atom number is significantly reduced, as a result, the carbon chain dependence of diffusion behaviors for long-chain n-alkane (n ≥ 5) and long-chain Ph-C{sub n} (n ≥ 4) in scCO{sub 2} are different.

  2. Transferable Potentials for Phase Equilibria. 4. United-Atom Description of Linear and Branched Alkenes and Alkylbenzenes

    SciTech Connect

    WICK,COLLIN D.; MARTIN,MARCUS G.; SIEPMANN,J. ILJA

    2000-07-12

    The Transferable Potentials for Phase Equilibria-United Atom (TraPPE-UA) force field for hydrocarbons is extended to alkenes and alkylbenzenes by introducing the following pseudo-atoms: CH{sub 2}(sp{sup 2}), CH(sp{sup 2}), CH(aro), R-C(aro) for the link to aliphatic side chains, and C(aro) for the link of two benzene rings. In this united-atom force field, the nonbonded interactions of the hydrocarbon pseudo-atoms are solely governed by Lennard-Jones 12-6 potentials, and the Lennard-Jones well depth and size parameters for the new pseudo-atoms were determined by fitting to the single-component vapor-liquid phase equilibria of a few selected model compounds. Configurational-bias Monte Carlo simulations in the NVT version of the Gibbs ensemble were carried out to calculate the single-component vapor-liquid coexistence curves for ethene, propene, 1-butene, trans- and cis-2-butene. 2-methylpropene, 1,5-hexadiene, 1-octene, benzene, toluene, ethylbenzene, propylbenzene, isopropylbenzene, o-, m-, and p-xylene, and naphthalene. The phase diagrams for the binary mixtures of (supercritical) ethene/n-heptane and benzene/n-pentane were determined from simulations in the NpT Gibbs ensemble. Although the TraPPE-UA force field is rather simple and makes use of relatively few different pseudo-atoms, its performance, as judged by comparisons to other popular force fields and available experimental data, is very satisfactory.

  3. Molecular dynamics simulation of diffusion coefficients and structural properties of some alkylbenzenes in supercritical carbon dioxide at infinite dilution.

    PubMed

    Wang, Jinyang; Zhong, Haimin; Feng, Huajie; Qiu, Wenda; Chen, Liuping

    2014-03-14

    The binary infinite dilute diffusion coefficients, D₁₂(∞), of some alkylbenzenes (Ph-C(n), from Ph-H to Ph-C12) from 313 K to 333 K at 15 MPa in supercritical carbon dioxide (scCO2) have been studied by molecular dynamics (MD) simulation. The MD values agree well with the experimental ones, which indicate MD simulation technique is a powerful way to predict and obtain diffusion coefficients of solutes in supercritical fluids. Besides, the local structures of Ph-C(n)/CO2 fluids are further investigated by calculating radial distribution functions and coordination numbers. It qualitatively convinces that the first solvation shell of Ph-C(n) in scCO2 is significantly influenced by the structure of Ph-C(n) solute. Meanwhile, the mean end-to-end distance, the mean radius of gyration and dihedral angle distribution are calculated to gain an insight into the structural properties of Ph-C(n) in scCO2. The abnormal trends of radial distribution functions and coordination numbers can be reasonably explained in term of molecular flexibility. Moreover, the computed results of dihedral angle clarify that flexibility of long-chain Ph-C(n) is the result of internal rotation of C-C single bond (σ(c-c)) in alkyl chain. It is interesting that compared with n-alkane, because of the existence of benzene ring, the flexibility of alkyl chain in Ph-C(n) with same carbon atom number is significantly reduced, as a result, the carbon chain dependence of diffusion behaviors for long-chain n-alkane (n ≥ 5) and long-chain Ph-C(n) (n ≥ 4) in scCO2 are different.

  4. Succinyl derivatives of N-tris (hydroxymethyl) methyl-2-aminoethane sulphonic acid: their effects on the frog neuromuscular junction.

    PubMed Central

    del Castillo, J.; Escalona de Motta, G.; Eterović, V. A.; Ferchmin, P. A.

    1985-01-01

    Succinic anhydride (SA) dissolved in Ringer solution buffered with N-tris (hydroxymethyl) methyl-2-aminoethane sulphonic acid (SA-TES solution) potentiates the depolarizing action of acetylcholine (ACh, 10-40 microM) on frog muscle and the tension induced by bath application of this agonist. Applied from one side of a double-barrelled micropipette, SA-TES increases the amplitude of iontophoretically elicited ACh potentials. The potentiation of the effects of ACh by SA-TES does not involve changes in either the activity of the ACh esterase or the input resistance of the muscle membrane. For depolarizations of frog sartorius muscle, dose-response relationships obtained for ACh concentrations from 0.5 to 20 microM indicate that SA-TES increases the apparent affinity of ACh by a factor of 3. SA-TES exerts an "accelerating' effect on the responses elicited by bath-applied ACh; i.e., it increases the rate of depolarization when ACh is added to the bath and the rate of repolarization upon washing out. These effects are particularly marked in preparations treated with neostigmine (3 microM). SA-TES does not potentiate the depolarizing action of agonists which do not contain an ester group. Moreover, the time course of the responses elicited by these compounds is not influenced by SA-TES. SA-TES fails to influence significantly the effects of the neurally released transmitter. Only a 10% increase in the average amplitude of the endplate potentials was observed. SA hydrolyzes in about 30 min at room temperature; however the SA-TES solution retains its activity for several weeks. Succinate is inactive, and so is SA in Ringer buffered with phosphate. The SA-TES solution contains seven succinyl-TES derivatives, which were separated by ion-exchange chromatography and paper chromatography. At concentrations between 1 to 150 microM, these succinyl-TES derivatives affected the ACh-induced contraction of frog rectus abdominus muscle. The most abundant derivative potentiated the

  5. Development of an equilibrium headspace gas chromatographic method for the measurement of noncovalent association and partitioning of n-alkylbenzenes at infinite dilution in fulvic acid pseudophase.

    PubMed

    Eljack, Mahmoud D; Wilson, Rachael E; Hussam, Abul; Khan, Shahamat U

    2015-02-27

    Fulvic acid (FA), the most important water soluble fraction of humic substances in nature, is known to form aggregate pseudophase and complexes with organic and inorganic species. Here, we report a novel equilibrium headspace gas chromatography (eHSGC) and a two-step reaction model to measure n-alkylbenzene-FA association constant (K11) and n-alkylbenzene-pseudophase FAn association constant (Kn1) without solute concentration and response factor. The K11 and Kn1 values were 2-3 orders of magnitude higher than those for sodium dodecylsulfate. Changes in peak area were used to calculate the critical FA-aggregation concentration (cfc), mole fraction based partition coefficients (Kx), activity coefficients of solute inside the aggregate pseudophase (γm(∞)), and transfer free energies of alkyl CH2 at infinite dilution. The cfc was found to be 10±0.5μM. The Kx values are of the order of 10(7) in the FA-aggregate pseudophase. The data shows that benzene has the lowest (0.0002) and n-butylbenzene has the highest (0.01) γm(∞) values, which are seven orders of magnitude smaller than γw(∞) in water. The transfer free energy of association of a CH2 group, -155cal/mol, compared to that of benzene, -9722cal/mol, indicates that the FA-aggregate pseudophase is more polarizable benzene-like and less n-alkane aliphatic-like.

  6. Phase equilibria study in binary systems (tetra-n-butylphosphonium tosylate ionic liquid + 1-alcohol, or benzene, or n-alkylbenzene).

    PubMed

    Domańska, Urszula; Paduszyński, Kamil

    2008-09-04

    Ambient pressure (solid + liquid) equilibria (SLE) and (liquid + liquid) equilibria (LLE) of binary systems--ionic liquid (IL) tetra- n-butylphosphonium p-toluenesulfonate + 1-alcohol (1-butanol, 1-hexanol, 1-octanol, 1-decanol, or 1-dodecanol), benzene, or n-alkylbenzene (toluene, ethylbenzene, n-propylbenzene)-have been determined by using dynamic method in a broad range of mole fractions and temperatures from 250 to 335 K. For binaries containing alcohol, simple eutectic diagrams were observed with complete miscibility in the liquid phase. Only in the case of system [IL + n-propylbenzene] was mutual immiscibility with an upper critical solution temperature (UCST) with low solubility of the IL in the alcohol and high solubility of the alcohol in the IL detected. The basic thermal properties of pure IL, i.e., melting and glass-transition temperatures as well as enthalpy of melting, have been measured with differential scanning microcalorimetry technique (DSC). Well-known UNIQUAC, Wilson, NRTL, NRTL1, and NRTL2 equations have been fitted to obtain experimental data sets. For the system containing immiscibility gap [IL + n-propylbenzene], parameters of the equations have been derived only from SLE data. As a measure of goodness of correlations, root-mean square deviations of temperature have been used. These experimental results were compared to the previously measured binary systems with tetra- n-butylphosphonium methanesulfonate. Changing anion from methanesulfonate to p-toluenesulfonate decreases solubilities in systems with alcohols and increases the solubilities in binary systems with benzene and alkylbenzenes.

  7. Back-flushing and heart cut capillary gas chromatography using planar microfluidic Deans' switching for the separation of benzene and alkylbenzenes in industrial samples.

    PubMed

    Jacobs, Matthew R; Gras, Ronda; Nesterenko, Pavel N; Luong, Jim; Shellie, Robert A

    2015-11-20

    Planar microfluidic devices coupled with modern electronic pressure control have allowed gas chromatography (GC) practitioners to easily manipulate chromatographic systems to achieve heart cut and back-flushing configurations. These planar microfluidic devices have enhanced the connectivity between different components of GC instrumentation and have improved the inertness and minimised system dead volumes compared to classical chromatographic unions and valves. In the present contribution the setup and configuration of two multidimensional GC (MDGC) platforms is described for achieving the separation and quantification of trace level target C6-C8 alkylbenzenes in styrene monomer and Isoparaffin™ solvents, using flame ionisation detection (FID). The performance of these MDGC platforms indicated excellent retention time (0.2% relative standard deviation, RSD) and peak area repeatability (1% RSD) for all analytes of interest. The limit of detection (LOD) was 0.8 mg kg(-1) for benzene in styrene monomer, and 2.4-2.8 mg kg(-1) for C6-C8 alkylbenzenes such as benzene, toluene, ethylbenzene and xylene in Isoparaffin™ solvent.

  8. Anaerobic degradation of alkylbenzenes in crude oil. II. Changes of oil composition upon incubation with sulfate-reducing and denitrifying bacteria

    SciTech Connect

    Wilkes, H.; Willsch, H.; Rabus, R.; Aeckersberg, F.

    1996-10-01

    Various alkylbenzenes in crude oils are degradable by several newly isolated sulfate-reducing and nitrate-reducing bacteria under strictly anoxic conditions. A mesophilic enrichment culture consisting of at least two different types of sulfate-reducing bacteria, depletes toluene, o- and m-xylene, o- and m-ethyltoluene, m-propyltoluene and m-cymene in crude oils at different rates. Experiments with different oils reveal that in general the degradation efficiency seems to depend not very strongly on the composition of the incubated oils. Results of our experiments with nitrate-reducing bacteria show that at least toluene, ethyltoluene and m-, p- and o-xylene in crude oils are biodegradable under denitrifying conditions. All organisms isolated so far exhibit a high substrate specifity. Up to now no indications for the alteration of other oil fractions, i.e. n-alkanes, biomarkers and PAH`s, could be observed with any of the bacteria used in this study. The possible role of alkylbenzene-degrading anaerobic bacteria in biodegradation of petroleums in natural environments will be discussed.

  9. Effect of the test media and toxicity of LAS on the growth of Isochrysis galbana.

    PubMed

    Garrido-Perez, M C; Perales-VargasMachuca, J A; Nebot-Sanz, E; Sales-Márquez, D

    2008-11-01

    In this paper, the toxicity of linear alkylbenzene sulfonate (LAS) was evaluated in the marine microalga Isochrysis galbana using data of growth inhibition toxicity tests at 96-h exposure time. Toxicity was examined in standard conditions and by means of the modification of two variables of the test media: (1) the dilution water and (2) the content of nutrients in the test medium. For this purpose, a total of 10 toxicity test were designed: five dilution waters, four natural marine waters and one synthetic seawater; each in two different nutritive conditions, saturated nutrient concentration (SC) by the addition of modified f/2 nutritive medium, and natural nutrient concentration (NC), i.e., without the addition of f/2. At threshold toxicity levels, the dilution waters used in the test and the nutrient concentrations did not affect the toxicity of LAS. At IC50 concentrations, the toxicity of LAS is influenced by both variables: under SC conditions, the toxic effect of LAS diminishes, obtaining in all the tests IC50 > 10 mg/L LAS. Under NC conditions, IC50 concentrations ranging between 3.15 and 9.26 mg/L LAS have been obtained.

  10. Las Vegas

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image of Las Vegas, NV was acquired on August, 2000 and covers an area 42 km (25 miles) wide and 30 km (18 miles) long. The image displays three bands of the reflected visible and infrared wavelength region, with a spatial resolution of 15 m. McCarran International Airport to the south and Nellis Air Force Base to the NE are the two major airports visible. Golf courses appear as bright red areas of worms. The first settlement in Las Vegas (which is Spanish for The Meadows) was recorded back in the early 1850s when the Mormon church, headed by Brigham Young, sent a mission of 30 men to construct a fort and teach agriculture to the Indians. Las Vegas became a city in 1905 when the railroad announced this city was to be a major division point. Prior to legalized gambling in 1931, Las Vegas was developing as an agricultural area. Las Vegas' fame as a resort area became prominent after World War II. The image is located at 36.1 degrees north latitude and 115.1 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  11. Effect of the structures of ionic liquids and alkylbenzene-derived amphiphiles on the inhibition of asphaltene precipitation from CO2-injected reservoir oils.

    PubMed

    Hu, Yu-Feng; Guo, Tian-Min

    2005-08-30

    The inhibition of asphaltene precipitation from high-pressure, CO(2)-injected reservoir oils by ionic and nonionic amphiphiles, the ionic liquids based on p-alkylpyridinium ([C(n)()py](+)) and N-butylisoquinolinium ([C(4)iql](+)) cations, and the alkylbenzene-derived amphiphiles p-alkylphenol (C(n)()phol), p-alkylbenzenesulfonic acid (C(n)()bsa), and sodium p-alkylbenzenesulfonate (C(n)()bsNa) was investigated for the first time. The influences of the structures of these compounds and the effect of the combination of their cations and anions were studied. The results show that the inhibition abilities of the alkylbenzene-derived amphiphiles first increase when n = 2-8 and then remain almost constant when n >/=8 and that the effectiveness follows the order C(n)()phol < C(n)()bsa approximately C(n)()bsNa. The inverse trend is observed for the ionic liquids [C(n)()py][Cl]; that is, their inhibition abilities decrease as n increases from 4 to 8 to 12. [C(4)iql][Cl] is more effective than [C(4)py][Cl], but [C(n)()py][BF(4)] and [C(n)()py][PF(6)] have almost no effect on the stabilization of asphaltenes. It was found that the effectiveness of an alkylbenzene-derived amphiphile on the inhibition of asphaltene precipitation from reservoir oils relies on its ability to form a stable steric-stabilization layer around asphaltenes, which is controlled by the polarity of its headgroup and the length of its alkyl tail. The novel mechanism of inhibiting asphaltene precipitation using the ionic liquids [C(n)()py] ([Cl], [BF(4)], and [PF(6)]) and [C(4)iql][Cl] was proposed. The mechanism states that the ionic liquids can effectively prevent asphaltene precipitation from the reservoir oils by breaking the asphaltene associations, which are due to the local nonneutrality of the charge densities of the cation and the anion. The ionic liquids that are based on an anion with high charge density, in connection with cations with sufficiently low charge densities, can effectively inhibit

  12. The taurine uptake inhibitor guanidinoethyl sulphonate is an agonist at gamma-aminobutyric acid(A) receptors in cultured murine cerebellar granule cells.

    PubMed

    Mellor, J R; Gunthorpe, M J; Randall, A D

    2000-05-26

    In patch clamp experiments the beta-amino acid uptake inhibitor guanidinoethyl sulphonate (GES) activated currents in intact cultured murine cerebellar granule neurones. These responses could be attenuated by the gamma-aminobutyric acid(A) (GABA(A)) receptor antagonists bicuculline and picrotoxin. With intracellular chloride concentrations of either 20 or 130 mM, GES-induced current responses reversed polarity near the chloride equilibrium potential. When fast applications of agonist were made to excised granule cell macropatches GES responses were dose-dependent and exhibited significant outward rectification. Like taurine (but unlike GABA and beta-alanine) responses, macroscopic desensitisation of GES-induced currents was slow. Our data indicate that care should be exercised when using GES as a taurine uptake inhibitor in systems that also contain GABA(A) receptors.

  13. Spectroscopic and semiempirical studies of the phototropic species of 8-amino-5,8'-azo-bis-naphthalene-2-sulphonic acid

    NASA Astrophysics Data System (ADS)

    Wojciechowska, Monika; Wojciechowski, Grzegorz; Wasiak, Wiesław

    2003-09-01

    Structural study of the azo compound obtained as a result of diazotization and coupling of 8-amino-naphthalene-2-sulfonic acid (Cleve's acid), has been performed by the spectroscopic methods 1H NMR and FTIR. UV-vis spectra of 8-amino-5,8'-azo-bis-naphthalene-2-sulphonic acid (CA-CA) were measured in water environment at different pH values and at a constant ionic strength. On the basis of the NMR, FTIR as well as on the grounds of a comparison of the experimental UV-vis spectra with those obtained by the MM/ PM5 in water followed by ZINDO method calculation, geometry of the CA-CA molecule in water solution has been proposed. Moreover, the value of the first dissociation constant of the dye has been determined (2.75×10 -2).

  14. Prophylactic effect of dietary glutamine supplementation on interleukin 8 and tumour necrosis factor α production in trinitrobenzene sulphonic acid induced colitis

    PubMed Central

    Ameho, C; Adjei, A; Harrison, E; Takeshita, K; Morioka, T; Arakaki, Y; Ito, E; Suzuki, I; Kulkarni, A; Kawajiri, A; Yamamoto, S

    1997-01-01

    Background—It is well established that glutamine supplemented elemental diets result in less severe intestinal damage in experimental colitis. However, few studies have examined the mode of action of glutamine in reducing intestinal damage. 
Aims—To examine the effects of glutamine supplemented elemental diets on the potent inflammatory cytokines interleukin 8 (IL-8) and tumour necrosis factor α (TNF-α) in trinitrobenzene sulphonic acid (TNBS) induced colitis which presents with both acute and chronic features of ulcerative colitis. 
Methods—Sprague-Dawley rats were randomised into three dietary groups and fed 20% casein (controls), or 20% casein supplemented with either 2% glutamine (2% Gln) or 4% glutamine (4% Gln). After two weeks they received intracolonic TNBS to induce colitis.
Results—Both Gln groups of rats gained more weight than the control group (p<0.05) which had progressive weight loss. Colon weight, macroscopic, and microscopic damage scores for the Gln groups were lower than in the control group (p<0.05). IL-8 and TNF-α concentrations in inflamed colonic tissues were lower in the Gln groups than in the control group (p<0.05), and correlated well with disease severity. Bacterial translocation was lower both in incidence (p<0.05) and in the number of colony forming units (p<0.05) for the Gln groups, than in the control group. With respect to all indices studied, the 4% Gln group performed better than did the 2% Gln group. 
Conclusion—Prophylactic glutamine supplementation modulates the inflammatory activities of IL-8 and TNF-α in TNBS induced colitis. 

 Keywords: glutamine; trinitrobenzene sulphonic acid; inflammatory bowel disease; rats; interleukin 8; tumour necrosis factor α PMID:9391247

  15. Spatial and temporal distribution of aliphatic hydrocarbons and linear alkylbenzenes in the particulate phase from a subtropical estuary (Guaratuba Bay, SW Atlantic) under seasonal population fluctuation.

    PubMed

    Dauner, Ana Lúcia L; Martins, César C

    2015-12-01

    Guaratuba Bay, a subtropical estuary located in the SW Atlantic, is under variable anthropogenic pressure throughout the year. Samples of surficial suspended particulate matter (SPM) were collected at 22 sites during three different periods to evaluate the temporal and spatial variability of aliphatic hydrocarbons (AHs) and linear alkylbenzenes (LABs). These compounds were determined by gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC/MS). The spatial distributions of both compound classes were similar and varied among the sampling campaigns. Generally, the highest concentrations were observed during the austral summer, highlighting the importance of the increased human influence during this season. The compound distributions were also affected by the natural geochemical processes of organic matter accumulation. AHs were associated with petroleum, derived from boat and vehicle traffic, and biogenic sources, related to mangrove forests and autochthonous production. The LAB composition evidenced preferential degradation processes during the austral summer.

  16. On the fate of LAS, NPEOs and DEHP in municipal sewage sludge during composting.

    PubMed

    Pakou, Constantina; Kornaros, Michael; Stamatelatou, Katerina; Lyberatos, Gerasimos

    2009-02-01

    The fate of hydrophobic xenobiotic pollutants such as linear alkylbenzene sulfonates (LAS), nonylphenol ethoxylates (NPEO) and di-ethyl-hexyl phthalate (DEHP) during sewage sludge composting was addressed in this work. The experiments were conducted in a fully automated in-vessel autothermal composting system which was fed with a mixture of primary and secondary sludge and manure. The mixture composition was determined to achieve satisfactory humidity, C/N ratio and free air space (FAS). The effect of various parameters, such as the initial xenobiotic concentration, the presence of multiple xenobiotic compounds and the temperature of composting material sustained during the process on the xenobiotics biodegradation kinetics was investigated. It was generally established that significant xenobiotic reduction is achievable through composting under all conditions tested. According to the obtained results, the presence of LAS, NPEO and DEHP even at higher concentrations was not inhibitory to the bioprocess. However, the presence of multiple xenobiotic compounds such as NPEO, NP and DEHP in the sludge can influence LAS removal during LAS composting.

  17. Electrochemical determination of Sudan I in food samples at graphene modified glassy carbon electrode based on the enhancement effect of sodium dodecyl sulphonate.

    PubMed

    Ma, Xinying; Chao, Mingyong; Wang, Zhaoxia

    2013-06-01

    This paper describes a novel electrochemical method for the determination of Sudan I in food samples based on the electrochemical catalytic activity of graphene modified glassy carbon electrode (GMGCE) and the enhancement effect of an anionic surfactant: sodium dodecyl sulphonate (SDS). Using pH 6.0 phosphate buffer solution (PBS) as supporting electrolyte and in the presence of 1.5 × 10(-4)mol L(-1) SDS, Sudan I yielded a well-defined and sensitive oxidation peak at a GMGCE. The oxidation peak current of Sudan I remarkably increased in the presence of SDS. The experimental parameters, such as supporting electrolyte, concentration of SDS, and accumulation time, were optimised for Sudan I determination. The oxidation peak current showed a linear relationship with the concentrations of Sudan I in the range of 7.50 × 10(-8)-7.50 × 10(-6)mol L(-1), with the detection limit of 4.0 × 10(-8)mol L(-1). This new voltammetric method was successfully used to determine Sudan I in food products such as ketchup and chili sauce with satisfactory results.

  18. Vitamin D treatment attenuates 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis but not oxazolone-induced colitis

    PubMed Central

    Liu, Tianjing; Shi, Yongyan; Du, Jie; Ge, Xin; Teng, Xu; Liu, Lu; Wang, Enbo; Zhao, Qun

    2016-01-01

    Crohn’s disease (CD) and ulcerative colitis (UC) have different immunological mechanisms, while both of them are potential targets of vitamin D treatment. In this study, we have tried to address the role of vitamin D in CD and UC using two mouse models. Mice of C57B6L were given vitamin D before the induction of colitis. Our results showed that vitamin D attenuated 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis but not oxazolone-induced colitis. Vitamin D could preserve the local histology, alleviate inflammation, suppress apoptosis, maintain tight junction function and decrease permeability. Interestingly, it has more of an effect on local structure preservation and inflammation inhibition in CD than in UC mice. Vitamin D blocked the increase of helper T-cell type 1 (Th1)- and helper T-cell type 17 (Th17)-related cytokines in TNBS-induced colitis. But the increase of helper T-cell type 2 (Th2)- and regulatory T cells (Treg)-related cytokines was augmented at the same time in oxazolone-induced colitis which counteracted each other. Our study helps elucidate the differential protective effects of vitamin D on CD and UC patients, as reported in literature. PMID:27620138

  19. Validated spectrophotometric method for the determination, spectroscopic characterization and thermal structural analysis of duloxetine with 1,2-naphthoquinone-4-sulphonate

    NASA Astrophysics Data System (ADS)

    Ulu, Sevgi Tatar; Elmali, Fikriye Tuncel

    2012-03-01

    A novel, selective, sensitive and simple spectrophotometric method was developed and validated for the determination of the antidepressant duloxetine hydrochloride in pharmaceutical preparation. The method was based on the reaction of duloxetine hydrochloride with 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline media to yield orange colored product. The formation of this complex was also confirmed by UV-visible, FTIR, 1H NMR, Mass spectra techniques and thermal analysis. This method was validated for various parameters according to ICH guidelines. Beer's law is obeyed in a range of 5.0-60 μg/mL at the maximum absorption wavelength of 480 nm. The detection limit is 0.99 μg/mL and the recovery rate is in a range of 98.10-99.57%. The proposed methods was validated and applied to the determination of duloxetine hydrochloride in pharmaceutical preparation. The results were statistically analyzed and compared to those of a reference UV spectrophotometric method.

  20. Periphyton biofilms: A novel and natural biological system for the effective removal of sulphonated azo dye methyl orange by synergistic mechanism.

    PubMed

    Shabbir, Sadaf; Faheem, Muhammad; Ali, Naeem; Kerr, Philip G; Wu, Yonghong

    2017-01-01

    Due to their large scale use, azo dyes are adversely affecting aquatic fauna and flora as well as humans. The persistent nature of sulphonated azo dyes makes them potential ecotoxic hazards. The aim of the present study was to employ a proficient, locally available biomaterial, viz. periphyton (i.e. epiphyton, epilithon or metaphyton), for removal of the azo dye, methyl orange (MO). Results showed that the periphytic biofilms are capable of completely removing comparatively high concentrations (up to 500 mg L(-1)) of MO from wastewater. The removal of MO occurs by a synergistic mechanism involving bioadsorption and biodegradation processes. The adsorption of MO by periphyton can be described by pseudo-second order kinetics. Elovich and intraparticle diffusion models as well as Langmuir equations fit well to the MO adsorption process. FTIR analysis of MO and its metabolites demonstrated biotransformation into simpler compounds within 72 h. GC-MS/MS analysis showed the conversion of MO into simpler compounds such as phenol, ethyl acetate and acetyl acetate. The results indicated that periphyton is a promising biomaterial for the complete removal of MO from wastewater and that the treatment process has the potential for in situ removal of MO at contaminated sites.

  1. Poly(ester sulphonic acid) coated mercury thin film electrodes: characterization and application in batch injection analysis stripping voltammetry of heavy metal ions.

    PubMed

    Brett, C M; Fungaro, D A

    2000-01-10

    Mercury-thin film electrodes coated with a thin film of poly(ester sulphonic acid) (PESA) have been investigated for application in the analysis of trace heavy metals by square wave anodic stripping voltammetry using the batch injection analysis (BIA) technique. Different polymer dispersion concentrations in water/acetone mixed solvent are investigated and are characterised by electrochemical impedance measurements on glassy carbon and on mercury film electrodes. The influence of electrolyte anion, acetate or nitrate, on polymer film properties is demonstrated, acetate buffer being shown to be preferable for stripping voltammetry applications. Although stripping currents are between 30 and 70% less at the coated than at bare mercury thin film electrodes, the influence of model surfactants on stripping response is shown to be very small. The effect of the composition of the modifier film dispersion on calibration plots is shown; however, detection limits of around 5 nM are found for all modified electrodes tested. This coated electrode is an alternative to Nafion-coated mercury thin film electrodes for the analysis of trace metals in complex matrices, particularly useful when there is a high concentration of non-ionic detergents.

  2. The anti-inflammatory potential of phenolic compounds in grape juice concentrate (G8000™) on 2,4,6-trinitrobenzene sulphonic acid-induced colitis.

    PubMed

    Paiotti, Ana Paula Ribeiro; Neto, Ricardo Artigiani; Marchi, Patrícia; Silva, Roseane Mendes; Pazine, Vanessa Lima; Noguti, Juliana; Pastrelo, Mauricio Mercaldi; Gollücke, Andréa Pittelli Boiago; Miszputen, Sender Jankiel; Ribeiro, Daniel Araki

    2013-09-28

    Chronic inflammatory bowel disease is characterised by an up-regulation of the synthesis and release of a variety of pro-inflammatory mediators leading to excessive tissue injury. Flavonoids are able to inhibit enzymes and/or due to their antioxidant properties regulate the immune response. The goal of the present study was to evaluate the mechanisms of action of phenolic compounds present in grape juice on 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. A total of forty-one male Wistar rats were randomised into seven groups: negative control group; TNBS non-treated induced colitis; 2% grape juice control group; 1% grape juice 24 h after TNBS colitis induction; 1% grape juice on day 7 after colitis induction; 2% grape juice 24 h after colitis induction; 2% grape juice on day 7 after colitis induction. The 1% grape juice-treated induced colitis group showed marked clinical improvement when compared with the TNBS-induced colitis group. Rats that received 1% grape juice, on day 7 after colitis induction, presented reduced intensity of macroscopic and histological scores. Statistically significant differences (P,0·05) of TNF-a and inducible NO synthase mRNA expression were detected in the groups treated with grape juice at the 1% dose after inducing experimental colitis when compared with the TNBS group. Grape juice reduced the noxious effects induced by colitis caused by TNBS, especially at the 1% dose.

  3. Polydimethylsiloxane composites containing 1,2-naphtoquinone 4-sulphonate as unique dispositive for estimation of casein in effluents from dairy industries.

    PubMed

    Muñoz-Ortuño, M; Argente-García, A; Moliner-Martínez, Y; Molins-Legua, C; Campíns-Falcó, P

    2015-05-11

    A unique dispositive to determine casein which is the most abundant protein in dairy sewages has been proposed. In this sensing technology, the derivatization reagent 1,2-naphtoquininone 4-sulphonate (NQS) is embedded into a polydimethylsiloxane-tetraethylortosilicate-SiO2 nanoparticles composite (PDMS-TEOS-SiO2NPs). When the composite is immersed into the samples, casein is extracted from the solution and derivatized inside the PDMS matrix after 10 min at 100°C. The sensing support changes its color from yellow to orange depending on the casein concentration. Quantitative analysis can be carried out by measuring the absorbance with a reflection probe or by image-processing tool (GIMP). This sensor provides good sensitivity and precision (RSD% <12%). The method validation has been done by applying the biocinchoninic acid method (BCA). Moreover, semiquatitative analysis of casein can be performed by visual observation. Taking into account the advantages of small size, rapidity, simplicity, good stability and high compatibility in aqueous solution, this sensor is expected to have potential practical applications for in-situ determination of casein. Finally the method has been applied to analyze effluents from dairy industries.

  4. Stabilization of asphaltenes in aliphatic solvents using alkylbenzene-derived amphiphiles. 1. Effect of the chemical structure of amphiphiles on asphaltene stabilization

    SciTech Connect

    Chang, C.L.; Fogler, H.S. )

    1994-06-01

    Stabilization of crude oil asphaltenes in apolar alkane solvents was investigated using a series of alkylbenzene-derived amphiphiles as the asphaltene stabilizers. In this paper (i.e., part I), we present the study on the influences of the chemical structure of these amphiphiles on the effectiveness of asphaltene solubilization and on the strength of asphaltene-amphiphile interaction using both UV/vis and FTIR spectroscopies. The results showed that the amphiphile's effectiveness of asphaltene stabilization was primarily controlled by the polarity of the amphiphile's head group and the length of the amphiphile's alkyl tail. Increasing the acidity of the amphiphile's head group could promote the amphiphile's ability to stabilize asphaltenes by increasing the acid-base attraction between asphaltenes and amphiphiles. On the other hand, although decreasing the amphiphile's tail length increased the asphaltene-amphiphile attraction slightly, it still required a minimum tail length (six carbons for p-alkylphenol amphiphiles) for amphiphiles to form stable steric layers around asphaltenes. We also found additional acidic side groups of amphiphiles could further improve the amphiphile's ability to stabilize asphaltenes. The effect of the molecular weight of alkane solvents on the amphiphile's ability to stabilize asphaltenes was also studied. 18 refs., 12 figs., 3 tabs.

  5. Coupling chemical oxidation and biostimulation: Effects on the natural attenuation capacity and resilience of the native microbial community in alkylbenzene-polluted soil.

    PubMed

    Martínez-Pascual, Eulàlia; Grotenhuis, Tim; Solanas, Anna M; Viñas, Marc

    2015-12-30

    Coupling chemical oxidation with bioremediation could be a cost-effective system to cope with soil and groundwater pollution. However, the effects of chemical oxidation on autochthonous microbial communities are scarcely known. A detailed analysis that considers both the efficiency of the two technologies and the response of the microbial communities was performed on a linear alkylbenzene-polluted soil and groundwater samples. The impacts of a modified Fenton's reaction (MFR) at various dosages and of permanganate on the microbiota over 4 weeks were assessed. The permanganate and MFR negatively affected microbial abundance and activity. However, the resilience of certain microbial populations was observed, with a final increase in potential hydrocarbon-degrading populations as determined by both the alkB gene abundance and the predominance of well-known hydrocarbon-degrading phylotypes such as Rhodococcus, Ochrobactrum, Acinetobacter and Cupriavidus genera as determined by 16S rRNA-based DGGE fingerprinting. The assessment of the chemical oxidant impact on autochthonous microbiota should be considered for the optimization of coupled field remediation technologies.

  6. An integrated evaluation of molecular marker indices and linear alkylbenzenes (LABs) to measure sewage input in a subtropical estuary (Babitonga Bay, Brazil).

    PubMed

    Martins, César C; Cabral, Ana Caroline; Barbosa-Cintra, Scheyla C T; Dauner, Ana Lúcia L; Souza, Fernanda M

    2014-05-01

    Babitonga Bay is a South Atlantic estuary with significant ecological function; it is part of the last remaining areas of mangrove communities in the Southern Hemisphere. The aim of this study was to determine the spatial distribution of the faecal sterols and linear alkylbenzenes (LABs) in surface sediments and to perform an integrated evaluation of several molecular marker indices to assess the sewage contamination status in the study area. The highest observed concentrations of faecal sterols (coprostanol + epicoprostanol) and LABs were 6.65 μg g(-1) and 413.3 ng g(-1), respectively. Several faecal sterol indices were calculated and correlated with coprostanol levels; these analyses showed that the index limits presented in the current literature could underestimate the sewage contamination in this study area. For the overall estuarine system, a low sewage impact may be assumed based on the low total mass inventories calculated for coprostanol (between 1.4% and 4.8%).

  7. Effect of sediment properties on the sorption of C12-2-LAS in marine and estuarine sediments.

    PubMed

    Rico-Rico, Angeles; Temara, Ali; Behrends, Thilo; Hermens, Joop L M

    2009-02-01

    Linear alkylbenzene sulfonates (LAS) are anionic high production volume surfactants used in the manufacture of cleaning products. Here, we have studied the effect of the characteristics of marine and estuarine sediments on the sorption of LAS. Sorption experiments were performed with single sediment materials (pure clays and sea sand), with sediments treated to reduce their organic carbon content, and with field marine and estuarine sediments. C12-2-LAS was used as a model compound. Sorption to the clays montmorillonite and kaolinite resulted in non-linear isotherms very similar for both clays. When reducing the organic content, sorption coefficients decreased proportionally to the fraction removed in fine grain sediments but this was not the case for the sandy sediment. The correlation of the sediment characteristics with the sorption coefficients at different surfactant concentrations showed that at concentrations below 10 microg C12-2-LAS/L, the clay content correlated better with sorption, while the organic fraction became more significant at higher concentrations.

  8. The water-soluble extract from cultured medium of Ganoderma lucidum (Reishi) mycelia (Designated as MAK) ameliorates murine colitis induced by trinitrobenzene sulphonic acid.

    PubMed

    Hanaoka, R; Ueno, Y; Tanaka, S; Nagai, K; Onitake, T; Yoshioka, K; Chayama, K

    2011-11-01

    Ganoderma lucidum Karst is well known as 'Reishi', a traditional food in China and Japan. It contains a polysaccharide component known to induce granulocyte macrophage colony-stimulating factor (GM-CSF) production from murine splenocytes. Moreover, GM-CSF may be a therapeutic agent for Crohn's disease. In this study, we investigated the water-soluble, polysaccharide components of Reishi (designated as MAK) in murine colitis induced by trinitrobenzene sulphonic acid (TNBS). We examined the concentration of GM-CSF in peritoneal macrophage cells (PMs) of C57BL/6 mice during in vitro and in vivo stimulation with MAK. After feeding with chow or MAK for 2 weeks, 2 mg of TNBS/50% ethanol was administered to each mouse. After 3 days of TNBS treatment, intestinal inflammation was evaluated, and mononuclear cells of the mesenteric lymph nodes (MLNs) and colon were cultured for ELISA. To determine the preventive role of GM-CSF, the mice were pre-treated with or without anti-GM-CSF antibody before TNBS administration. In vitro and in vivo MAK-stimulated PMs produced GM-CSF in a dose-dependent manner. Intestinal inflammation by TNBS was improved by feeding with MAK. MLNs of mice treated with TNBS produced IFN-γ, which was inhibited by feeding with MAK. In contrast, MLNs of mice treated with TNBS inhibited GM-CSF production, which was induced by feeding with MAK. The colon organ culture assay also revealed that IFN-γ was decreased and GM-CSF was increased by MAK. The preventive effect was blocked by the neutralization of GM-CSF. We concluded that the induction of GM-CSF by MAK may provide the anti-inflammatory effect.

  9. Development of a novel biosensor based on a polypyrrole-dodecylbenzene sulphonate (PPy-DBS) film for the determination of amperometric cholesterol.

    PubMed

    Özer, Bayram Oğuz; Çete, Servet

    2017-06-01

    Herein a novel amperometric biosensor based on a conducting polymer with anionic dopant modified electrode was successfully developed for detection of cholesterol. Polypyrrole is deposited on a platinum surface and the sodium dodecylbenzene sulphonate (DBS) ion-doped polypyrrole film was electrochemically prepared by scanning the electrode potential between -0.8 and +0.8 V at a scan rate of 20 mV/s. The present electrochemical biosensor was optimized in terms of working potential, number of cycles, concentrations of monomer, and anionic dopant. Cholesterol oxidase (ChOx) was physically entrapped in PPy-DBS to construct an amperometric cholesterol biosensor. Amperometric determination is based on the electrochemical detection of H2O2 generated in the enzymatic reaction of cholesterol. Kinetic parameters, operational and storage stabilities, pH, and temperature dependencies were determined. Km and Imax were calculated as 0.11 μM and 0.967 nM/min, respectively. The operational stability results showed that 90.0% of the response current was retained after 30 activity assays. Morphology of electrodes was characterized by SEM and AFM. Additionally, contact angle measurements were made with 1 μL water of polymer film and enzyme electrode. As a result, the cholesterol biosensor suggested in this study is easy to prepare and is highly cost-effective. This composite (PPy-DBS) can supply a biocompatible and electrochemical microenvironment for immobilization of the enzyme, making this material a good candidate for the fabrication of highly sensitive and selective cholesterol biosensors.

  10. Spectrophotometric study for the reaction between fluvoxamine and 1,2-naphthoquinone-4-sulphonate: Kinetic, mechanism and use for determination of fluvoxamine in its dosage forms

    NASA Astrophysics Data System (ADS)

    Darwish, Ibrahim A.; Abdine, Heba H.; Amer, Sawsan M.; Al-Rayes, Lama I.

    2009-05-01

    Spectrophotometric study was carried out, for the first time, to investigate the reaction between the antidepressant fluvoxamine (FXM) and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 9), an orange-colored product exhibiting maximum absorption peak ( λmax) at 470 nm was produced. The kinetics of the reaction was investigated and its activation energy was found to be 2.65 kcal mol -1. Because of this low activation energy, the reaction proceeded easily. The stoichiometry of the reaction was determined and the reaction mechanism was postulated. This color-developing reaction was successfully employed in the development of simple and rapid spectrophotometric method for determination of FXM in its pharmaceutical dosage forms. Under the optimized reaction conditions, Beer's law correlating the absorbance ( A) with FXM concentration ( C) was obeyed in the range of 0.6-8 μg ml -1. The regression equation for the calibration data was A = 0.0086 + 0.1348 C, with good correlation coefficient (0.9996). The molar absorptivity ( ɛ) was 5.9 × 10 4 l mol -1 cm -1. The limits of detection and quantification were 0.2 and 0.6 μg ml -1, respectively. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2%. The proposed method was successfully applied to the determination of FXM in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.47 ± 0.96%. The results obtained by the proposed method were comparable with those obtained by the official method. The proposed method is superior to all the previously reported spectrophotometric methods for determination of FXM in terms of its simplicity and sensitivity. The method is practical and valuable for its routine application in quality control laboratories for analysis of FXM.

  11. Determination of total non-sulphonated aromatic amines in soft drinks and hard candies by reduction and derivatization followed by high-performance liquid chromatography.

    PubMed

    Lancaster, F E; Lawrence, J F

    1992-01-01

    Utilizing elements of methodology developed previously for food colours, total free and bound non-sulphonated aromatic amines (NSAA) were determined in commercial samples of soft drink beverages and hard candies. Bound amines in the samples were reduced using sodium dithionite, then total NSAA were extracted into chlorofom, transferred to aqueous acid solution and diazotized with sodium nitrite before coupling with 2-naphthol-3,6-disulphonic acid, disodium salt (R-salt). The coloured derivatives were analysed using reversed-phase ion pair high-performance liquid chromatography (HPLC) and an absorbance detector set at 512 nm. Solid phase extraction cartridges were utilized for extraction and clean-up of the food colours present in the sample, and the concentration of each dye was determined quantitatively using HPLC and absorbance detector wavelengths of 426, 516 or 625 nm. Levels of total NSAA were compatible with those observed previously in food colours. Commercial soft drinks were found to contain (expressed in terms of total free plus bound NSAA in the beverage) 0.19-12.6 ng/ml of aniline, 0.83-8.25 ng/ml 1-naphthylamine and 0.62-1.12 ng/ml 2-naphthylamine. Levels of 0.66-9.15 ng/g of aniline and 2.48-10.6 ng/g 1-naphthylamine were found in commercial samples of hard candies. Bound NSAA in hard candies appeared to survive the manufacturing process. Recoveries averaged 96.9% for tartrazine and 89.6-97.2% for the bound amines when hard candies were prepared in the laboratory.

  12. Colitogenic role of tumour necrosis factor (TNF) receptors in trinitrobenzene sulphonic acid colitis: TNF-R1 ablation does not affect systemic inflammatory response.

    PubMed

    Yang, Y; Wang, H; Dou, Y; Wang, Y; Han, G; Wang, Renxi; Wang, L; Guo, R; Xiao, H; Li, X; Shen, B; Shi, Y; Chen, G; Li, Y

    2011-09-01

    Tumour necrosis factor (TNF)-α plays a critical role in the pathogenesis of T helper type 1-mediated colitis such as Crohn's disease. However, the roles of its two receptors in mediating pathology remain largely unknown. In this study, trinitrobenzene sulphonic acid (TNBS) was used to induce colitis in TNF-receptor single or double knock-out (DKO) BALB/c mice and in wild-type counterparts. TNF-R1(-/-) mice had significantly less weight loss, reduced mortality, colon shortening and oedema, colon histological damage and lower levels of colon myeloperoxidase compared with wild-type (WT) BALB/c mice. A similar manifestation was also observed in TNF-R2(-/-) and TNF-R1(-/-) TNF-R2(-/-) (TNF-R DKO) mice. Strikingly, systemic inflammatory response (including splenomegaly and monocyte expansion) was found in WT and TNF-R1(-/-) mice after TNBS, instead of TNF-R2(-/-) and TNF-R DKO mice. Attenuated pathology of colitis in TNF-R1(-/-) or TNF-R2(-/-) mice correlated with lower amounts of interleukin (IL)-6, IL-1β, monocyte chemotactic protein (MCP)-1, IL-12p70 and interferon (IFN)-γ production in the colons. Importantly, ablation of TNF-R1 or TNF-R2 reduced the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling (TUNEL)-positive apoptotic epithelial cells in the affected colons compared with WT TNBS-instilled controls, which might be due to the heightened ratio of Bcl-2/Bax and reduced activity of nuclear factor (NF)-κB. These findings suggest that either TNF-R1 or TNF-R2 plays a pathogenic role in the pathology of colitis and TNF signalling via TNF-R1 or TNF-R2 alone is not sufficient for inducing mucosal damage.

  13. Linear alkylbenzenes as tracers of sewage-sludge-derived inputs of organic matter, PCBs, and PAHs to sediments at the 106-mile deep water disposal site

    USGS Publications Warehouse

    Lamoureux, E.M.; Brownawell, Bruce J.; Bothner, Michael H.

    1996-01-01

    Linear alkylbenzenes (LABs) are sensitive source-specific tracers of sewage inputs to the marine environment. Because they are highly particle reactive and nonspecifically sorbed to organic matter, LABs are potential tracers of the transport of both sludge-derived organic matter and other low solubility hydrophobic contaminants (e.g., PCBs and PAHs); sediment trap studies at the 106-Mile Site have shown LABs to be valuable in testing models of sludge deposition to the sea floor. In this study we report on the distributions of LABs, PCBs, PAHs, and Ag in surface sediments collected within a month of the complete cessation of dumping (July, 1992) in the vicinity of the dump site. Total LAB concentrations were lower than those measured by Takada and coworkers in samples from nearby sites collected in 1989. LABs from both studies appear to be significantly depleted (6 to 25-fold) in surface sediments relative to excess Ag (another sludge tracer) when compared to sewage sludge and sediment trap compositions. Comparison of LAB sediment inventories to model predictions of sludge particle fluxes supports the contention that LABs have been lost from the bed. The use of LABs to examine the short-or long-term fate of sludge derived materials in deep-sea sediments should be questioned. The causes of this LAB depletion are unclear at this point, and we discuss several hypotheses. The concentrations of total PCBs and PAHs are both correlated with sludge tracers, suggesting that there may be a measurable contribution of sludge-derived inputs on top of other nonpoint sources of these contaminant classes. This possibility is consistent with the composition of these contaminants determined in recent and historical analyses of sewage sludge.

  14. Material with high dielectric constant, low dielectric loss, and good mechanical and thermal properties produced using multi-wall carbon nanotubes wrapped with poly(ether sulphone) in a poly(ether ether ketone) matrix

    NASA Astrophysics Data System (ADS)

    Zhang, Shuling; Wang, Hongsong; Wang, Guibin; Jiang, Zhenhua

    2012-07-01

    A material with high dielectric constant, low dielectric loss, and good mechanical and thermal properties was produced using multi-wall carbon nanotubes (MWCNTs) wrapped with poly(ether sulphone) (PES) dispersed in a poly(ether ether ketone) (PEEK) matrix. The material was fabricated using melt-blending, and MWCNT/PEEK composites show different degrees of improvement in the measured dielectric, mechanical, and thermal properties as compared to pure PEEK. This is attributed to the high conductivity of MWCNTs, the effect of wrapping MWCNTs with PES, the good dispersion of the wrapped MWCNTs in PEEK, and the strong interfacial adhesion between the wrapped MWCNTs and the PEEK.

  15. Correlation of distribution of sulphonated aluminium phthalocyanines with their photodynamic effect in tumour and skin of mice bearing CaD2 mammary carcinoma.

    PubMed Central

    Peng, Q.; Moan, J.

    1995-01-01

    A chemical extraction assay and fluorescence microscopy incorporating a light-sensitive thermoelectrically cooled charge-coupled device (CCD) camera was used to study the kinetics of uptake, retention and localisation of disulphonated aluminium phthalocyanine (A1PcS2) and tetrasulphonated aluminium phthalocyanine (A1PcS4) at different time intervals after an i.p. injection at a dose of 10 mg kg-1 body weight (b.w.) in tumour and surrounding normal skin and muscle of female C3D2/F1 mice bearing CaD2 mammary carcinoma. Moreover, the photodynamic effect on the tumour and normal skin using sulphonated aluminium phthalocyanines (A1PcS1, A1PcS2, A1pcS4) and Photofrin was compared with respect to dye, dye dose and time interval between dye administration and light exposure. The maximal concentrations of A1PcS2 in the tumour tissue were reached 2-24 h after injection of the dye, while the amounts of A1PcS4 peaked 1-2 h after the dye administration. A1PcS2 was simultaneously localised in the interstitium and in the neoplastic cells of the tumour, whereas A1PcS4 appeared to localise only in the stroma of the tumour. The photodynamic efficiency (light was applied 24 h after dye injection at a dose of 10 mg kg-1 b.w.) of the tumours was found to decrease in the following order: A1PcS2 > A1PcS4 > Photofrin > A1PcS1. Furthermore, photodynamic efficacy was strongly dependent upon dye doses and time intervals between dye administration and light exposure: the higher the dose, the higher the photodynamic efficiency. The most efficient photodynamic therapy (PDT) of the tumour was reached (day 20 tumour-free) when light exposure took place 2 h after injection of A1PcS2 (10 mg kg-1). A dual intratumoral localisation pattern of the dye, as found for A1PcS2, seems desirable to obtain a high photodynamic efficiency. The kinetic patterns of uptake, retention and localisation of A1PcS2 and A1PcS4 are roughly correlated with their photodynamic effect on the tumour and normal skin. Images

  16. Characterization of the properties of stationary phases for liquid chromatography in aqueous mobile phases using aromatic sulphonic acids as the test compounds.

    PubMed

    Jandera, P; Bocian, S; Molíková, M; Buszewski, B

    2009-01-09

    We investigated the effects of the concentration of naphthalene sulphonic acids (NSAs) as anionic test compounds in the injected sample and of the salt additives to the mobile phase on ion-exclusion. The retention behaviour of NSAs sensitively reflects even minor changes in the ionic and hydrophobic interactions and can be useful for predicting the effects of the stationary phases in reversed-phase chromatography of polar and ionic compounds, both small ones and biopolymers, e.g., oligonucleotides. We studied chromatographic properties of several stationary phases intended for separations in aqueous mobile phases: a C18 column end-capped with polar hydrophilic groups, a densely bonded C8 column doubly end-capped with short alkyl groups, a short alkyl stationary phase designed to keep full pore accessibility in highly-aqueous mobile phases and a Bidentate column with "bridged" C18 groups attached to the silica hydride support. The chemistry and pore structure of various types of column packing materials and of the salt additives to the mobile phase affect the proportion of the pore volume non-accessible to anions due to ion-exclusion and consequently the peak asymmetry and hydrophobic selectivity in reversed-phase chromatography of organic acids. We also addressed the problems connected with the determination of column hold-up volume in aqueous mobile phases. The accessibility of the stationary phase for anionic compounds in contact with the sample zone is affected by ion-exclusion due to repulsive interactions with the negatively charged surface in the pores of the stationary phase. The accessible part of the stationary phase increases and consequently the migration velocity along the column decreases with increasing concentration of the sample in the zone moving along the column. Because of a limited access to the stationary phase, its capacity can be easily overloaded. The combination of the column overload and ion-exclusion effects may result in fronting or

  17. Stabilization of asphaltenes in aliphatic solvents using alkylbenzene-derived amphiphiles. 2. Study of the asphaltene-amphiphile interactions and structures using Fourier transform infrared spectroscopy and small-angle X-ray scattering techniques

    SciTech Connect

    Chang, C.L.; Fogler, H.S. )

    1994-06-01

    In the preceding paper in this issue, the influence of the chemical structure of a series of alkylbenzene-derived amphiphiles on the stabilization of asphaltenes was described. In this paper, we present the results of using Fourier transform infrared (FTIR) spectroscopy and small-angle X-ray scattering (SAXS) techniques to study the interaction between asphaltenes and two alkylbenzene-derived amphiphiles, p-alkylphenol and p-alkylbenzenesulfonic acid. FTIR spectroscopy was used to characterize and quantify the acid-base interactions between asphaltenes and amphiphiles. It was found that asphaltenes could hydrogen-bond to p-dodecylphenol amphiphiles. The hydrogen-bonding capacity of asphaltenes was estimated to be 1.6-2.0 mmol/g of asphaltene. On the other hand, the FTIR spectroscopic study indicated that asphaltenes had a complicated acid-base interaction with p-dodecylbenzenesulfonic acid (DBSA) amphiphiles with a stoichiometry of about 1.8 mmol of DBSA/g of asphaltene. The UV/vis spectroscopic study suggested that asphaltenes and DBSA could associate into large electronic conjugated complexes. Physical evidence of the association between asphaltenes and amphiphiles was obtained by SAXS measurements. 27 refs., 10 figs.

  18. LAS bioconcentration is isomer specific

    SciTech Connect

    Tolls, J.; Haller, M.; Graaf, I. de; Thijssen, M.H.C.; Sijm, D.T.H.M.

    1995-12-31

    The authors measured parent compound specific bioconcentration data for linear alkylbenzene sulfonates in Pimephales promelas. They did so by using cold, custom synthesized sulfophenyl alkanes. They observed that, within homologous series of isomers, the uptake rate constants (k{sub 1}) and the bioconcentration factor (BCF) increase with increasing number of carbon atoms in the alkyl chain (n{sub C-atoms}). In contrast, the elimination rate constant k{sub 2} appears to be independent of the alkyl chain length. Regressions of log BCF vs n{sub C-atoms} yielded different slopes for the homologous groups of the 5- and the 2-sulfophenyl alkane isomers. Regression of all log BCF-data vs log 1/CMC yielded a good description of the data. However, when regressing the data for both homologous series separately again very different slopes are obtained. The results therefore indicate that hydrophobicity-bioconcentration relationships may be different for different homologous groups of sulfophenyl alkanes.

  19. Degradative capacities and 16S rRNA-targeted whole-cell hybridization of sulfate-reducing bacteria in an anaerobic enrichment culture utilizing alkylbenzenes from crude oil.

    PubMed Central

    Rabus, R; Fukui, M; Wilkes, H; Widdle, F

    1996-01-01

    A mesophilic sulfate-reducing enrichment culture growing anaerobically on crude oil was used as a model system to study which nutritional types of sulfate-reducing bacteria may develop on original petroleum constituents in oil wells, tanks, and pipelines. Chemical analysis of oil hydrocarbons during growth revealed depletion of toluene and o-xylene within 1 month and of m-xylene, o-ethyltoluene, m-ethyltoluene, m-propyltoluene, and m-isopropyltoluene within approximately 2 months. In anaerobic counting series, the highest numbers of CFU (6 x 10(6) to 8 x 10(6) CFU ml-1) were obtained with toluene and benzoate. Almost the same numbers were obtained with lactate, a substrate often used for detection of the vibrio-shaped, incompletely oxidizing Desulfovibrio sp. In the present study, however, lactate yielded mostly colonies of oval to rod-shaped, completely oxidizing, sulfate-reducing bacteria which were able to grow slowly on toluene or crude oil. Desulfovibrio species were detected only at low numbers (3 x 10(5) CFU ml-1). In agreement with this finding, a fluorescently labeled, 16S rRNA-targeted oligonucleotide probe described in the literature as specific for members of the Desulfovibrionaceae (suggested family) hybridized only with a small portion (< 5%) of the cells in the enrichment culture. These results are consistent with the observation that known Desulfovibrio species do not utilize aromatic hydrocarbons, the predominant substrates in the enrichment culture. All known sulfate-reducing bacteria which utilize aromatic compounds belong to a separate branch, the Desulfobacteriaceae (suggested family). Most members of this family are complete oxidizers. For specific hybridization with members of this branch, the probe had to be modified by a nucleotide exchange. Indeed, this modified probe hybridized with more than 95% of the cells in the enrichment culture. The results show that completely oxidizing, alkylbenzene-utilizing sulfate-reducing bacteria rather than

  20. Equilibrium partitioning theory to predict the sediment toxicity of the anionic surfactant C(12)-2-LAS to Corophium volutator.

    PubMed

    Rico-Rico, Angeles; Temara, Ali; Hermens, Joop L M

    2009-02-01

    The study of the effect of the sorption of linear alkylbenzene sulfonates (LAS) on the bioavailability to marine benthic organisms is essential to refine the environmental risk assessment of these compounds. According to the equilibrium partitioning theory (EqP), the effect concentration in water-only exposure will be similar to the effect concentration in the sediment pore water. In this work, sorption and desorption experiments with two marine sediments were carried out using the compound C(12)-2-LAS. The effect of the sediment sorption on the toxicity of benthic organisms was studied in water-only and in sediment bioassays with the marine mud shrimp Corophium volutator. In addition, three common spiking methods were tested for its application in the toxicity tests, as well as the stability of the surfactant during the water-only and sediment-water test duration. LC50 values obtained from water-only exposure showed a good correspondence with the pore water concentrations calculated from the sorption and desorption isotherms in the spiked sediments.

  1. VOLATILIZATION OF ALKYLBENZENES FROM WATER.

    USGS Publications Warehouse

    Rathbun, R.E.; Tai, D.Y.

    1985-01-01

    Volatilization is a physical process of importance in determining the fate of many organic compounds in streams and rivers. This process is frequently described by the conceptual-two-film model. The model assumes uniformly mixed water and air phases separated by thin films of water and air in which mass transfer is by molecular diffusion. Mass-transfer coefficients for the water and air films are related to an overall mass-transfer coefficient for volatilization through the Henry's law constant.

  2. New rapid methods for determination of total LAS in sewage sludge by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE).

    PubMed

    Villar, M; Callejón, M; Jiménez, J C; Alonso, E; Guiraúm, A

    2009-02-23

    Linear alkylbenzene sulfonates (LAS) are the most common synthetic anionic surfactant used in domestic and industrial detergents, with a global production of 2.4x10(6) t year(-1). After use and disposal, LAS may enter the environment by one of the several routes, including by direct discharge to surface water or discharge to water from sewage treatment plants. Sewage treatment plants break down LAS only partly: some of them remain in effluent and other fraction is adsorbed in sewage solid. New and rapid methods for determination of total LAS from sewage sludge based on microwave assisted extraction and HPLC-FL and CE-DAD determination are proposed. The extraction of total LAS is carried out by using microwaves energy, an extraction time of 10 min and 5 mL of methanol. For HPLC-FL determination, mobile phase acetonitrile-water was used, comprising 60% (v/v) from 0 to 1 min and a flow rate of 1 mL min(-1) programmed to 100% acetonitrile between 1 and 2 min and a flow rate of 2 mL min(-1). The final composition was maintained for a further 5 min. The determination of total LAS by CE-DAD was performed in a phosphate buffer (10 mM, pH 9). The separation voltage was 25 kV and the temperature of the capillary was 30 degrees C. Injections were performed in the pressure mode and the injection time was set at 12 s. The determination of total LAS is carried out in less than 5 min. The methods did not require clean-up or preconcentration steps. Detection limit for total LAS in the sludge was 3.03 mg kg(-1) using HPLC-FL and 21.0 mg kg(-1) using CE-DAD, and recoveries were >85% using both determination methods. Concentrations of total LAS obtained using both methods were compared with the sum of concentrations of homologues LAS C-10, LAS C-11, LAS C-12 and LAS C-13 obtained using microwaves assisted extraction and HPLC-FL and CE-DAD determination.

  3. Association of two single-isomer anionic CD in NACE for the chiral and achiral separation of fenbendazole, its sulphoxide and sulphone metabolites: application to their determination after in vitro metabolism.

    PubMed

    Rousseau, Anne; Gillotin, Florian; Chiap, Patrice; Crommen, Jacques; Fillet, Marianne; Servais, Anne-Catherine

    2010-05-01

    A NACE method was developed for the separation of fenbendazole (FBZ), a prochiral drug giving rise to chiral (oxfendazole or OFZ) and nonchiral (FBZ sulphone or FBZSO(2)) metabolites. First, the effect of the nature and the concentration of CD as well as that of the acidic BGE on the enantiomeric separation of OFZ were studied. OFZ enantiomers were completely resolved using a BGE made up of 10 mM ammonium formate and 0.5 M TFA in methanol containing 10 mM heptakis(2,3-di-O-acetyl-6-O-sulfo)-beta-CD and 10 mM heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-CD. Moreover, the NACE method was found to be particularly well suited to the simultaneous determination of FBZ, OFZ enantiomers, and FBZSO(2). Thiabendazole was selected as an internal standard. The CD-NACE potential was then evaluated for in vitro metabolism studies using FBZ as a model case. The OFZ enantiomers and FBZSO(2) could be detected after incubation of FBZ in the phenobarbital-induced male rat liver microsomes systems.

  4. Investigation of properties of copper, ferrous complexes with 1-(5-bromo-2-pyridylazo)-2-naphthol-6-sulphonic acid and application of substitution reaction in metallic complex to selective determination of trace amounts of metal.

    PubMed

    Gao, H W

    2000-08-16

    The report was the first to establish the new method for the selective determination of trace amounts of metal using the substitution reaction in metallic complex. The reactions between copper(II) and 1-(5-bromo-2-pyridylazo)-2-naphthol-6-sulphonic acid (BPANS) and between ferrous(II) and BPANS at pH 3.5 were studied. In absence of any masking reagent, the recommended method was selective in the determination of trace amounts of copper with Fe-BPANS complex as chromogenic reagent because copper(II) can substitute Fe from Fe-BPANS complex to form Cu-BPANS complex. The ordinary spectrophotometric method was unsuitable to the substitution reaction because the excess of Fe-BPANS complex had the high absorption and affected seriously the absorption of Cu-BPTANS complex. The spectral correction principle may eliminate the above influence to give the simple determination of the composition ratio, stepwise absorptivity (epsilon) and stability constant (K) of metal complex. For analysis of samples, the recovery of copper was between 96.5 and 106% with R.S.D. less than 5%.

  5. Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Pease, P. B.

    1989-01-01

    Version 4.1 of LAS provides flexible framework for algorithm development and processing and analysis of image data. Over 500,000 lines of code enable image repair, clustering, classification, film processing, geometric registration, radiometric correction, and manipulation of image statistics.

  6. Ionic-liquid-modified magnetic nanoparticles as a solid-phase extraction adsorbent coupled with high-performance liquid chromatography for the determination of linear alkylbenzene sulfonates in water samples.

    PubMed

    Lu, Junyu; Ye, Fanggui; Huang, Xiuxiang; Wei, Lianqiang; Yao, Dongmei; Li, Shengying; Ouyang, Miao; Lai, Hongfang

    2017-03-01

    Novel ionic-liquid-functionalized Fe3 O4 magnetic nanoparticles were synthesized by the thiol-ene click reaction. The prepared functionalized Fe3 O4 nanoparticles possessed multiple interactions, such as electrostatic, hydrophobic, and π-π interactions. The functionalized Fe3 O4 nanoparticles were characterized by using Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometry, and transmission electron microscopy. Four kinds of linear alkylbenzene sulfonates, namely, sodium decylbenzenesulfonate, sodium undecylbenzene sulfonate, sodium dodecylbenzenesulfonate, and sodium tridecylbenzenesulfonate, were selected as model compounds to evaluate the applicability of adsorbents for extraction and subjected to high-performance liquid chromatography analysis. In addition, the effects of various parameters, such as sorbent amount, pH value, ionic strength, sample volume, extraction time, and elution conditions on extraction efficiency were studied in detail. Under the optimum conditions, good linearities were attained, with correlation coefficients between 0.9912 and 0.9968. The proposed method exhibited limits of detection ranging from 0.061 to 0.099 μg/L for all the target analytes. The spiked recoveries of the target analytes in real water samples ranged from 86.3 to 107.5%, with relative standard deviations lower than 7.96%. The enrichment factors of the analytes ranged from 364 to 391, indicating that the obtained functionalized Fe3 O4 nanoparticles can effectively extract trace target analytes from environmental water samples.

  7. Development of a fully automated sequential injection solid-phase extraction procedure coupled to liquid chromatography to determine free 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid in human urine.

    PubMed

    León, Zacarías; Chisvert, Alberto; Balaguer, Angel; Salvador, Amparo

    2010-04-07

    2-Hydroxy-4-methoxybenzophenone and 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid, commonly known as benzophenone-3 (BZ3) and benzophenone-4 (BZ4), respectively, are substances widely used as UV filters in cosmetic products in order to absorb UV radiation and protect human skin from direct exposure to the deleterious wavelengths of sunlight. As with other UV filters, there is evidence of their percutaneous absorption. This work describes an analytical method developed to determine trace levels of free BZ3 and BZ4 in human urine. The methodology is based on a solid-phase extraction (SPE) procedure for clean-up and pre-concentration, followed by the monitoring of the UV filters by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). In order to improve not only the sensitivity and selectivity, but also the precision of the method, the principle of sequential injection analysis was used to automate the SPE process and to transfer the eluates from the SPE to the LC system. The application of a six-channel valve as an interface for the switching arrangements successfully allowed the on-line connection of SPE sample processing with LC analysis. The SPE process for BZ3 and BZ4 was performed using octadecyl (C18) and diethylaminopropyl (DEA) modified silica microcolumns, respectively, in which the analytes were retained and eluted selectively. Due to the matrix effects, the determination was based on standard addition quantification and was fully validated. The relative standard deviations of the results were 13% and 6% for BZ3 and BZ4, respectively, whereas the limits of detection were 60 and 30 ng mL(-1), respectively. The method was satisfactorily applied to determine BZ3 and BZ4 in urine from volunteers that had applied a sunscreen cosmetic containing both UV filters.

  8. Sulphonic acid strong cation-exchange restricted access columns in sample cleanup for profiling of endogenous peptides in multidimensional liquid chromatography. Structure and function of strong cation-exchange restricted access materials.

    PubMed

    Machtejevas, E; Denoyel, R; Meneses, J M; Kudirkaite, V; Grimes, B A; Lubda, D; Unger, K K

    2006-08-04

    In this work, the pore structural parameters and size exclusion properties of LiChrospher strong cation-exchange and reverse phase restricted access materials (RAM) are analysed. The molecular weight size exclusion limit for polystyrenes was found to be about 17.7 kDa, while for standard proteins, the molecular weight size exclusion limit was higher, at approximately 25 kDa. The average pore diameter on a volume basis calculated from the pore network model changes from 8.5 nm (native LiChrospher) to 8.6 nm (diol derivative) to 8.2 nm (sulphonic acid derivative) to 6.9 nm (n-octadecyl derivative). Additional characterisations were performed on restricted access materials with nitrogen sorption at 77 K, water adsorption at 25 degrees C, intrusion-extrusion of water (in order to evaluate the hydrophobic properties of the pores of the hydrophobic RAM), and zeta potential measurements by microelectrophoresis. For peptide analysis out of the biofluids, the strong cation-exchange functionality seems to be particularly suitable mainly because of the high loadability of the strong cation-exchange restricted access material (SCX-RAM) and the fact that one can work under non-denaturing conditions to perform effective chromatographic separations. For bacitracin, the dynamic capacity of the SCX-RAM columns does not reach its maximum value in the analysed range. For lysozyme, the dynamic capacity reaches a value of 0.08 mg/ml of column volume before column is overloaded. Additionally, the proper column operating conditions that lead to the total effective working time of the RAM column to be equal to approximately 500 injections (depending on the type of sample), is comprehensively described. The SCX-RAM column was used in the same system analysing urine samples for the period of 1 month (approximately 150 injections) with run-to-run reproducibility below 5% RSD and below 10% RSD for the relative fractions.

  9. Integration of aquatic fate and ecological responses to linear alkyl benzene sulfonate (LAS) in model stream ecosystems.

    PubMed

    Belanger, S E; Bowling, J W; Lee, D M; LeBlanc, E M; Kerr, K M; McAvoy, D C; Christman, S C; Davidson, D H

    2002-06-01

    An integrated model stream ecosystem fate and effect study of dodecyl linear alkylbenzene sulfonate (C(12)LAS) was performed in the summer and fall of 1996. The study addressed responses of periphytic microbes, immature benthic fauna including abundance, drift, and emergence of adult insects in a 56-day exposure. Exposures ranged from 126 to 2978 microg/L and were continuously presented in a single-pass, flow-through test system. Microbial heterotrophs acclimated to C(12)LAS exposure quickly (14 days) and biodegraded C(12)LAS at all concentrations. Blue-green algae responded by increasing in abundance with increasing C(12)LAS concentration. Invertebrates responded by increased drift and reduced benthic abundances at concentrations exceeding 293 microg/L. Emergence at 927 microg/L also declined relative to the control. Adverse responses for mayflies and chironomids were indicated using univariate statistical techniques. Multivariate techniques indicated these taxa plus mollusks, aquatic worms, caddisflies, and stoneflies were impaired at some concentrations. Bioavailability of C(12)LAS was investigated in streams as a function of the total suspended solid load in the water column driven by local weather and watershed patterns. A continuous bioavailability model indicated exposure was reduced by an average of 8.5+/-8.9%. A model ecosystem no-observed-effect concentration (NOEC) was concluded to be 293 microg/L based on measured water column exposure and adjusted to 268 microg/L by the bioavailability model. A literature review of 13 available model ecosystem studies was conducted and NOEC conclusions were adjusted by a structure-activity relationship to a dodecyl chain length (sulfophenyl position and distribution being ignored due to lack of information in the reviewed studies). Lentic studies (n=7) were found to have higher NOECs than lotic studies (n=6) and were more variable. Mean NOECs+/-SD for all studies, lentic studies only, and lotic studies only were 3320

  10. Las Campanas Stellar Library

    NASA Astrophysics Data System (ADS)

    Chilingarian, Igor; Zolotukhin, Ivan; Beletsky, Yuri; Worthey, Guy

    2015-08-01

    Stellar libraries are fundamental tools required to understand stellar populations in star clusters and galaxies as well as properties of individual stars. Comprehensive libraries exist in the optical domain, but the near-infrared (NIR) domain stays a couple of decades behind. Here we present the Las Campanas Stellar Library project aiming at obtaining high signal-to-noise intermediate-resolution (R=8000) NIR spectra (0.83<λ<2.5μm) for a sample of 1200 stars in the Southern sky using the Folded-port InfraRed Echelette spectrograph at the 6.5-m Magellan Baade telescope. We developed a dedicated observing strategy and customized the telescope control software in order to achieve the highest possible level of data homogeniety. As of 2015, we observed about 600 stars of all spectral types and luminosity classes making our library the largest homogeneous collection of stellar spectra covering the entire NIR domain. We also re-calibrated in flux and wavelength the two existing optical stellar libraries, INDO-US and UVES-POP and followed up about 400 non-variable stars in the NIR in order to get complete optical-NIR coverage. Worth mentioning that our current sample includes about 80 AGB stars and a few dozens of bulge/LMC/SMC stars.

  11. Bioaccumulation and toxicity of 4-nonylphenol (4-NP) and 4-(2-dodecyl)-benzene sulfonate (LAS) in Lumbriculus variegatus (Oligochaeta) and Chironomus riparius (Insecta).

    PubMed

    Mäenpää, K; Kukkonen, J V K

    2006-05-10

    The discharge of surfactants, such as 4-nonylphenol (4-NP) and linear alkylbenzene sulfonates (LAS), into water bodies leads to accumulation of the chemicals in the sediments and may thus pose a problem to benthic organisms. To study the bioaccumulation of surfactants, Oligochaeta worm Lumbriculus variegatus was exposed to sediment-spiked, [14C]-labeled 4-NP and 4-(2-dodecyl)-benzene sulfonate (C12-LAS) in three different sediments (S1-S3). The sediments were characterized for organic carbon (OC) content and particle size distribution. The acute toxicity was examined by exposing L. variegatus and three to four instar Chironomus riparius (Insecta) larvae in water-only exposure to 4-NP and LAS at different concentrations. After 48-h exposure, lethal water concentrations (LC50) and lethal body residues (LBR50) were estimated using liquid scintillation counting. Chronic toxicity was evaluated in two different sediments by exposing first instar C. riparius larvae to sediment-spiked chemicals at different concentrations. After 10 days, the sublethal effects of surfactants were observed by measuring wet weight and head capsule length. Finally, another 10-day test was set up in order to measure the LAS body residues associated with sublethal effects in C. riparius in S2 sediment. The bioaccumulation test revealed that the bioaccumulation of both 4-NP and LAS increased as the sediment organic matter content decreased. It is assumed that the chemical binding to organic material decreased chemical bioavailability. The acute toxicity tests showed that L. variegatus was more tolerant of 4-NP, and C. riparius was more tolerant of LAS when based on water exposure concentration. The LBR-estimates revealed, however, that L. variegatus tolerated clearly higher tissue residues of both chemicals compared with C. riparius. Both chemicals had sublethal effects on C. riparius growth in sediment exposure, reducing larvae wet weight and head capsule size. 4-NP, however, showed an irregular

  12. The Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Lu, Yun-Chi; Irani, Fred M.

    1991-01-01

    The Land Analysis System (LAS) is an interactive software system, available in the public domain, for the analysis, display, and management of multispectral and other digital image data. The system was developed to support earth sciences research and development activities. LAS provides over 240 applications functions and utilities, a flexible user interface, complete on-line and hardcopy documentation, extensive image data file management, reformatting, and conversion utilities, and high level device independent access to image display hardware. The capabilities are summarized of the latest release of the system (version 5). Emphasis is given to the system portability and the isolation of hardware and software dependencies in this release.

  13. Precipitation of alkylbenzene sulfonates with metal ions

    SciTech Connect

    Peacock, J.M.; Matijevic, E.

    1980-10-01

    The precipitation domains of P-(1-methylnonyl)benzene sulfonate ions with Li/sup +/, Na/sup +/, K/sup +/, Ca/sup 2 +/, Mg/sup 2 +/, Al/sup 3 +/, and La/sup 3 +/ and of Ca/sup 2 +/-P-(hexyloctyl)benzene sulfonate have been determined at constant pH and 25 C. The linear solubility boundaries reverse their slope at the critical micellar concentration of the surfactant. A semiquantitative interpretation of the data is offered. The properties of the solids formed also are described. 18 references.

  14. EMPACT: THE LAS VEGAS INTERAGENCY PILOT PROGRAM

    EPA Science Inventory

    ENPACT: The Las Vegas Interagency Pilot Project

    The Las Vegas Interagency Pilot Project of the EMPACT program has involved eleven efforts. These efforts are described in brief on the poster presentation. They include: Las Vegas Environmental Monitoring Inventory, the Qual...

  15. Calidad del aire interior en las escuelas

    EPA Pesticide Factsheets

    EPA ha desarrollado el Programa de Herramientas de Calidad del Aire Interior para las Escuelas para reducir la exposición a los contaminantes ambientales en las mismas a través de la adopción voluntaria de las prácticas para manejar la calidad del aire int

  16. Partitioning of hydrophobic pesticides within a soil-water-anionic surfactant system.

    PubMed

    Wang, Peng; Keller, Arturo A

    2009-02-01

    Surfactants can be added to pesticide-contaminated soils to enhance the treatment efficiency of soil washing. Our results showed that pesticide (atrazine and diuron) partitioning and desorbability within a soil-water-anionic surfactant system is soil particle-size dependent and is significantly influenced by the presence of anionic surfactant. Anionic surfactant (linear alkylbenzene sulphonate, LAS) sorption was influenced by its complexation with both the soluble and exchangeable divalent cations in soils (e.g. Ca2+, Mg2+). In this study, we propose a new concept: soil system hardness which defines the total amount of soluble and exchangeable divalent cations associated with a soil. Our results showed that anionic surfactant works better with soils having lower soil system hardness. It was also found that the hydrophobic organic compounds (HOCs) sorbed onto the LAS-divalent cation precipitate, resulting in a significant decrease in the aqueous concentration of HOC. Our results showed that the effect of exchangeable cations and sorption of HOC onto the surfactant precipitates needs to be considered to accurately predict HOC behavior within soil-water-anionic surfactant systems.

  17. Leaving Las Vegas: Exposure to Las Vegas and risk of suicide.

    PubMed

    Wray, Matt; Miller, Matthew; Gurvey, Jill; Carroll, Joanna; Kawachi, Ichiro

    2008-12-01

    Residents of Las Vegas, Nevada have much higher suicide rates than residents of other metropolitan counties in the USA. Whether the risk of suicide among visitors to Las Vegas is also significantly elevated has been difficult to assess because person-time denominator information is not available. We used a case-control design to examine the association between exposure to Las Vegas and risk of suicide expressed as mortality odds ratios. We conceptualized four different types of potential suicide risk with respect to Las Vegas: (1) risk of suicide among usual residents of Las Vegas ("chronic risk"), (2) risk of suicide among temporary visitors to Las Vegas ("acute risk"), (3) risk of suicide among Las Vegas residents visiting elsewhere ("leaving Las Vegas risk"), and (4) risk of suicide among travelers in general ("traveler risk"). Controlling for age, gender, marital status, and year effects, the odds of suicide among Las Vegas residents was at least 50% greater than among residents elsewhere in each of the three decades we observed. Visitors to Las Vegas were at double the risk compared to those who stayed in their home county. Leaving Las Vegas was associated with a greater than 20% reduction in risk for suicide. Traveling to Las Vegas is associated with a twofold increase in risk compared to traveling elsewhere. We discuss three possible theoretical frameworks to help explain our observed results: ecological effects, whereby social factors unique to Las Vegas, or uniquely amplified in Las Vegas, result in increased risk to both residents and visitors; selection effects whereby those predisposed to suicide disproportionately choose Las Vegas to reside in and visit; and contagion effects, whereby high numbers of suicides tend to lead to even greater numbers over time, as people emulate the suicides of others. We compare our empirical evidence for each of the effects with existing sociological and historical scholarship on Las Vegas.

  18. Analysis of the methodology to determine anaerobic toxicity: evaluation of main compounds present in wastewater treatment plants (WWTPs).

    PubMed

    Urra, J; Poirrier, P; Segovia, J; Lesty, Y; Chamy, R

    2008-01-01

    The influence of the concentration of biomass on the level of inhibition and anaerobic degradation kinetics in batch systems was studied with toxic compounds that can generate destabilization in the operation of sludge anaerobic digesters. The compounds were grouped in four families; long chain fatty acids, polycyclic aromatic hydrocarbons, linear alkylbenzene sulphonates and organic acids. For the organic acids, there is no effect due to the biomass concentration variation, therefore it is a competitive inhibition; but that doesn't happen with the remaining compounds, where there is a dependence on the complexity of their structure, becoming a non-competitive inhibition. In addition, it was observed that the degradation kinetics is affected, whether diminishing the methane production (polycyclic aromatic hydrocarbons, linear alkylbenzene sulphonates, organics acids) or increasing the initial latency time (long chain fatty acids) without this becoming an obstacle to obtain the maximum methane productions for the latter ones.

  19. Acerca de las ratas y los ratones

    EPA Pesticide Factsheets

    Hay muchas especies de roedores, entre ellas, la ardilla, la ardilla listada, el castor, el perro de la pradera, la rata y el ratón. Se puede ver las medidas más importantes para eliminar y prevenir las infestaciones causadas por roedores.

  20. Las ideologias, las ciencias naturales y sus implicaciones en la educacion cientifica

    NASA Astrophysics Data System (ADS)

    Lozada Roldan, Sandra

    Este estudio ausculto las concepciones epistemologicas de los docentes de ciencia del nivel secundario con relacion a las ideologias y las ciencias naturales. Tambien examino las posiciones de los docentes ante asuntos publicos relacionados a la ciencia. Para propositos de este estudio se diseno y se valido el cuestionario con el cual se obtuvieron los resultados. La investigacion es de tipo cuantitativa y se utilizo como diseno la encuesta. El cuestionario se administro en varias actividades de desarrollo profesional para maestros de ciencia. Un total de 78 maestros del nivel secundario respondieron el cuestionario. Para analizar los datos obtenidos se utilizaron estadisticas descriptivas como la distribucion de frecuencia y el porciento. Ademas se establecieron codigos y categorias para describir las posiciones de los maestros ante asuntos publicos relacionados a la ciencia. Los analisis demostraron que entre los docentes participantes de este estudio prevalecen ciertas concepciones epistemologicas adecuadas acerca de las ciencias naturales, a la luz de la literatura consultada. Entre estas concepciones se destacan las siguientes: a) la filosofia materialista de las ciencias naturales, b) la naturaleza tentativa y constructivista del conocimiento cientifico, c) el uso de una metodologia que garantiza cierto grado de objetividad y con el que se justifican y validan los enunciados cientificos y d) la funcion instrumental del conocimiento cientifico. Sin embargo, entre los docentes participantes de este estudio prevalecen ciertas concepciones epistemologicas erroneas acerca de las ciencias naturales, a la luz de la literatura consultada. Entre estas concepciones se destacan las siguientes: a) tendencia inductivista en el que las teorias cientificas comienzan con observaciones que establecen generalizaciones, b) secuencia jerarquica de la metodologia cientifica. Ademas, entre los docentes participantes de este estudio prevalecen concepciones epistemologicas adecuadas

  1. Occurrence of high-tonnage anionic surfactants in Spanish sewage sludge.

    PubMed

    Cantarero, Samuel; Prieto, Carlos A; López, Ignacio

    2012-03-01

    Agricultural application has become the most widespread method of sewage sludge disposal, being the most economical outlet for sludge and also recycling beneficial plant nutrients and organic matter to soil for crop production. As a matter of fact, the European Sewage Sludge Directive 86/278/EEC seeks to encourage the disposal of sewage sludge in agriculture applications and regulate its use to prevent harmful effects on the soil environment. At the present time, the sewage sludge Directive is under revision and a possible cut-off limit for some organic chemicals may be implemented. Linear alkylbenzene sulphonate (LAS), the main synthetic anionic surfactant, has been included in the draft list of chemicals to be limited. The present research work deals with the monitoring of LAS and soap in Spanish sewage sludge. The average concentration of LAS found in anaerobic sewage sludge samples was 8.06 g/kg, higher than the average values for European sludge. Besides, it has been also found that more than 55% of Spanish anaerobic sludge would not fulfil the limit proposed by the 3rd European Working paper on sludge. As a consequence, the implementation of the limit for LAS would make the disposal of most Spanish biosolids for agricultural applications almost impossible. Regarding the mechanisms why anionic surfactants are found in sludge, two surfactants are compared: LAS and soap, both readily biodegraded in aerobic conditions. Irrespective of the anaerobic biodegradability of soap, its concentration found in sludge is higher than LAS (only anaerobically biodegradable under particular conditions). The relevance of anaerobic biodegradation to assure environmental protection is discussed for this case.

  2. GREAT-ER: a new tool for management and risk assessment of chemicals in river basins. Contribution to GREAT-ER #10.

    PubMed

    Schowanek, D; Fox, K; Holt, M; Schroeder, F R; Koch, V; Cassani, G; Matthies, M; Boeije, G; Vanrolleghem, P; Young, A; Morris, G; Gandolfi, C; Feijtel, T C

    2001-01-01

    The GREAT-ER (Geo-referenced Regional Exposure Assessment Tool for European Rivers) project team has developed and validated an accurate aquatic chemical exposure prediction tool for use within environmental risk assessment schemes. The software system GREAT-ER 1.0 calculates the distribution of predicted environmental concentrations (PECs) of consumer chemicals in surface waters, for individual river stretches as well as for entire catchments. The system uses an ARC/INFO-ArcView (ESRI) based Geographical Information System (GIS) for data storage and visualization, combined with simple mathematical models for prediction of chemical fate. At present, the system contains information for four catchments in Yorkshire, one catchment in Italy, and two in Germany, while other river basins are being added. Great-ER 1.0 has been validated by comparing simulations with the results of an extensive monitoring campaign for two 'down-the-drain' chemicals, i.e. the detergent ingredients boron and Linear Alkylbenzene Sulphonate (LAS). GREAT-ER 1.0 is currently being expanded with models for the terrestrial (diffuse input), air and estaurine compartments.

  3. Overview of the land analysis system (LAS)

    USGS Publications Warehouse

    Quirk, Bruce K.; Olseson, Lyndon R.

    1987-01-01

    The Land Analysis System (LAS) is a fully integrated digital analysis system designed to support remote sensing, image processing, and geographic information systems research. LAS is being developed through a cooperative effort between the National Aeronautics and Space Administration Goddard Space Flight Center and the U. S. Geological Survey Earth Resources Observation Systems (EROS) Data Center. LAS has over 275 analysis modules capable to performing input and output, radiometric correction, geometric registration, signal processing, logical operations, data transformation, classification, spatial analysis, nominal filtering, conversion between raster and vector data types, and display manipulation of image and ancillary data. LAS is currently implant using the Transportable Applications Executive (TAE). While TAE was designed primarily to be transportable, it still provides the necessary components for a standard user interface, terminal handling, input and output services, display management, and intersystem communications. With TAE the analyst uses the same interface to the processing modules regardless of the host computer or operating system. LAS was originally implemented at EROS on a Digital Equipment Corporation computer system under the Virtual Memorial System operating system with DeAnza displays and is presently being converted to run on a Gould Power Node and Sun workstation under the Berkeley System Distribution UNIX operating system.

  4. Determination of plasma total homocysteine and cysteine using HPLC with fluorescence detection and an ammonium 7-fluoro-2, 1, 3-benzoxadiazole-4-sulphonate (SBD-F) derivatization protocol optimized for antioxidant concentration, derivatization reagent concentration, temperature and matrix pH.

    PubMed

    Daskalakis, I; Lucock, M D; Anderson, A; Wild, J; Schorah, C J; Levene, M I

    1996-01-01

    A sensitive HPLC-fluorescence method for determining total endogenous plasma homocysteine (Hcy), cysteine (Cys) and cysteinylglycine (Cys-Gly) following derivatization with ammonium 7-fluoro 2,1,3-benzoxadiazole-4-sulphonate (SBD-F) is described. Quantitation utilizes an internal standard, 2-mercaptoethylamine. The derivatization procedure has been optimized for concentration of SBD-F, reducing agent (tributylphosphine) and temperature. Findings indicate that values for plasma determinations vary according to the nature of the matrix in which calibration standards are made up. If quantitation is based on a peak height ratio, then standards should be made up in either pH 7.4 phosphate buffered saline or plasma taking into account the endogenous thiol concentration. These findings are based on calibration data, and 30 plasma samples quantified using thiol standards made up in plasma, pH 7.4 and pH 9.5 buffers. By defining how this matrix/pH effect influences thiol quantitation, it should be possible to make a more meaningful comparison of Hcy measurements between laboratories. The chromatographic separation was investigated at several mobile-phase pH values with the following conditions ascertained to be optimal: a mobile phase consisting of 5% (v/v) acetonitrile in 0.1 M KH2PO4, pH 2.15 was run at a flow rate of 0.5 mL/min. It was used in conjunction with a Supelco LC-18 base deactivated analytical column (150 x 4.6 cm i.d. 3 microM bonded silica). The internal standard and thiols were measured by fluorescence detection at 385 nm excitation and 515 nm emmission. Plasma levels are easily measured in a 100 microL volume. Storage for 2 months at -20 degrees C resulted in no deterioration of thiols. Furthermore, no difference in thiol levels was observed between bloods collected in lithium heparin and EDTA. Collected blood should, however, be separated as soon as possible to avoid red cell metabolism of Hcy which was observed in a case of hyperhomocysteinemia. Once

  5. Degradation and environmental risk of surfactants after the application of compost sludge to the soil.

    PubMed

    González, M M; Martín, J; Camacho-Muñoz, D; Santos, J L; Aparicio, I; Alonso, E

    2012-07-01

    In this work, the degradation of anionic and non-ionic surfactants in agricultural soil amended with sewage sludge is reported. The compounds analysed were: linear alkylbenzene sulphonates (LAS) with a 10-13 carbon alkylic chain, and nonylphenolic compounds (NPE), including nonylphenol (NP) and nonylphenol ethoxylates with one and two ethoxy groups (NP1EO and NP2EO). The degradation studies were carried out under winter (12.7°C) and summer (22.4°C) conditions in Andalusia region. The concentration of LAS was reduced to 2% of the initial concentration 100 day after sludge-application to the soil. The half-life time measured for LAS homologues were ranged between 4 and 14days at 12.7°C and between 4 and 7 days at 22.4°C. With regard to NPE compounds, after 8 and 4days from the beginning of the experiment at 12.7 and 22.4°C, respectively, their concentration levels were increased to 6.5 and 13.5mg/kgdm (dry matter) as consequence of the degradation of nonylphenol polyethoxylates. These concentration levels were reduced to 5% after 63 and 70 days for 12.7°C and 22.4°C, respectively. The half-life times measured for NPEs were from 8 to 16 days at 12.7°C and from 8 to 18 days at 22.4°C. Environmental risk assessment revealed that for LAS homologues no environment risk could be expected after 7 and 8 days of sludge application to the soil for 22.4 and 12.7°C, respectively; however, potential toxic effects could be observed for the nonylphenolic compounds during the first 56 days after sludge application to the soil.

  6. EPA orders City of North Las Vegas to safeguard Las Vegas Wash from potential water pollution

    EPA Pesticide Factsheets

    SAN FRANCISCO - The U.S. Environmental Protection Agency issued an order to the City of North Las Vegas to take immediate steps to address federal Clean Water Act violations. Deficiencies in the management of its wastewater pretreatment program have

  7. LANDSCAPE CHANGE OF THE LAS VEGAS VALLEY, 1972 TO 1998

    EPA Science Inventory

    Las Vegas has become one of the fastest growing metropolitan areas in the United States. The cities population has doubled from 1980 to 1994 and in 1995 Las Vegas has surpassed the one million mark. The population of Las Vegas is currently growing at a rate of 7 percent annually....

  8. Occurrence of selected surfactants in untreated and treated sewage.

    PubMed

    Clara, M; Scharf, S; Scheffknecht, C; Gans, O

    2007-11-01

    Several surfactants were monitored in treated and untreated sewage in nine municipal wastewater treatment plants (WWTPs) in western Austria. The nine sampled WWTPs cover a wide variety referring to size and applied treatment technology. The investigation focused on linear alkylbenzene sulphonate (LAS), quaternary ammonia compounds (QAC), nonylphenol (NP), octylphenol (OP), nonylphenolmono- (NP(1)EO) and -diethoxylates (NP(2)EO). Whereas LAS, NP, OP and NP(1,2)EO were analysed separately in the liquid phase and in the solid phase, the QACs were measured in the total sample. Total influent concentrations of LAS varied between 2.4 mg l(-1) up to 6.7 mg l(-1) whereas total effluent concentrations were in the lower microg l(-1) range (11-50 microg l(-1)). Whichever the type of treatment, a clear removal during treatment was observed. Solid liquid distribution coefficients K(d) were calculated for untreated sewage. The calculated K(d) values varied between 1300 and 3900 l kg(-1). OP was of minor importance with total influent concentrations below 1microg l(-1). NP and NP(1,2)EO were present in all analysed influents in concentrations between 1 and 35microg l(-1). Effluent concentrations were notably lower than the measured influent concentrations. K(d) values for NP varied between 500 and 6600 l kg(-1), for NP(1)EO between 800 and 2700 l kg(-1) and for NP(2)EO between 100 and 1800 l kg(-1). From the QACs several alkyl benzyl (BAC), dialkyl (DDAC) and trialkyl (ATAC) ammonium chlorides with varying alkyl chain lengths were analysed. Highest total concentrations in the influents to the WWTPs were observed for the BAC-C12 and the ATAC-C16 homologues. Effluent concentrations were notably lower compared to influent concentrations, indicating removal by adsorption and/or biodegradation. The influence of the removal by adsorption increased with increasing alkyl chain length.

  9. ?Cuales son las amenazas o peligros volcanicos?

    USGS Publications Warehouse

    Myers, Bobbie; Brantley, Steven R.; Stauffer, Peter; Hendley, James W.

    2000-01-01

    Los volcanes son capaces de producir numerosos peligros geologicos e hidrologicos. Los cientificos del Servicio Geologico de los EE. UU. (USGS, por sus siglas en ingles) y de otras instituciones alrededor del mundo estan estudiando los peligros de muchos de los centenares de volcanes activos y potencialmente activos del mundo. Estos cientificos vigilan muy de cerca la actividad de algunos de los volcanes mas peligrosos, por lo que estan preparados para alertar a las autoridades y/o a la poblacion en caso de que aumente sustancialmente la probabilidad de que ocurra una erupcion u otro evento peligroso.

  10. Resource Conservation and a Sustainable Las Vegas

    SciTech Connect

    Piechota, Thomas C.

    2014-05-15

    This research project developed educational, research, and outreach activities that addressed the challenges of Las Vegas as related to a secure energy supply through conservation, clean and adequate water supply, economic growth and diversification, air quality, and the best use of land, and usable public places. This was part of the UNLV Urban Sustainability Initiative (USI) that responded to a community and state need where a unifying vision of sustainability was developed in a cost-effective manner that promoted formal working partnerships between government, community groups, and industry.

  11. ANAEROBIC BIODEGRADATION OF ALKYLBENZENES IN LABORATORY MICROCOSMS REPRESENTING AMBIENT CONDITIONS

    EPA Science Inventory

    A microcosm study was performed to document the anaerobic biodegradation of benzene, toluene, ethylbenzene, m- xylene, and/or o-xylene in petroleum-contaminated aquifer sediment from sites in Michigan (MI) and North Carolina (NC) and relate the results to previous field investiga...

  12. Relevamiento de HI en las Nubes de Magallanes

    NASA Astrophysics Data System (ADS)

    Bajaja, E.; Morras, R.; Arnal, E. M.; Pöppel, W. G. L.

    El relevamiento de HI en el hemisferio sur, que se está realizando desde el IAR con el nuevo receptor enfriado, abarca, en su rango de velocidades, las velocidades desplegadas por el hidrógeno neutro de las Nubes de Magallanes. Esto permite obtener los perfiles de velocidad correspondientes a estas galaxias con una sensibilidad y una completitud de grilla excepcionales para el estudio de la distribución y de la cinemática del gas a gran escala y con una resolución angular de 30' y una resolución en velocidad de 1 km/s. Estas condiciones permiten el estudio de los campos de velocidad, de las componentes múltiples en velocidad, de las asimetrías, concentraciones y burbujas en la distribución del gas, los puentes entre las Nubes y entre las Nubes y la Galaxia, etc. Estas características son de particular importancia para su correlación con los mapas obtenidos con las emisiones en el radio-continuo, el IR y el CO (relacionable con el hidrógeno molecular) todas las cuales permiten el estudio de la dinámica de las Nubes y su relación con la Galaxia, de la formación y evolución estelar y de la evolución de la Nubes mismas.

  13. Variación temporal de las constantes fundamentales

    NASA Astrophysics Data System (ADS)

    Landau, S. J.; Vucetich, H.

    La variación temporal de las constantes fundamentales es un problema que ha motivado numerosos trabajos teóricos y experimentales desde la hipótesis de los grandes números de Dirac en 1937. Entre los métodos experimentales y observacionales para establecer restricciones sobre la variación de las constantes fundamentes es importante mencionar: comparación entre relojes atómicos[1], métodos geofísicos[2][3], análisis de sistemas de absorción en quasares[4][5][6] y cotas provenientes de la nucleosíntesis primordial[7]. En un trabajo reciente[5], se reportó una significativa variación en la constante de estructura fina. Intentos de unificar las cuatro interacciones fundamentales dieron como resultado teorías con múltiples dimensiones como las teorías de Kaluza-Klein y teorías de supercuerdas. Estas teorías proporcionan un marco teórico natural para el estudio de la variación temporal de las constantes fundamentales. A su vez, un modelo sencillo para estudiar la variación de la constante de estructura fina, fue propuesto en [8], a partir de premisas muy generales como ser covarianza, invarianza de gauge, causalidad y invarianza ante reversiones temporales en el electromagnetismo. Diferentes versiones de las teorías antes mencionadas coinciden en predecir variaciones temporales de las constantes fundamentales pero difieren en la forma de esta variación[9][10]. De esta manera, las restricciones establecidas experimentalmente sobre la variación de las constantes fundamentales pueden ser una herramienta importante para testear estas diferentes teorías. En este trabajo, utilizamos las cotas provenientes de diversas técnicas experimentales, para testear si las mismas son consistentes con alguna de las teorías antes mencionadas. En particular, establecemos cotas sobre la variación de los parámentros libres de las diferentes teorías como por ejemplo el radio de las dimensiones extras en las teorías tipo Kaluza-Klein.

  14. The Las Campanas Infrared Survey Camera

    NASA Astrophysics Data System (ADS)

    Persson, S. E.; Murphy, D. C.; Gunnels, S. M.; Birk, C.; Bagish, A.; Koch, E.

    2002-07-01

    The Las Campanas Infrared Survey Camera is a near-infrared (1.0-2.5 μm), wide-area instrument used to detect and measure the photometric properties of galaxies out to large redshifts, z>2. The camera, a modified Offner 1:1 reimaging optical system, is mounted at the f/7.5 focus of the 2.5 m du Pont Telescope. The detectors are four Rockwell 1024×1024 HgCdTe (HAWAII) arrays operating at a scale of 0.20" pixel-1. With four telescope pointings, the instrument produces a pipelined mosaic of J, H, or Ks images 13'×13' on the sky, with a measured point-spread function as good as 0.38" FWHM. The good imaging quality results in part from fast tip-tilt guiding on stars within a 9'×9' field centered on the optical axis of the telescope. Appropriately bright guide stars are found within 2 s from a catalog of 5×107 stars and presented as a ``finding chart'' to the observer. The optical, mechanical, and thermal design choices and their associated engineering implementations are discussed in some detail. The detector readout electronics, the automatic data acquisition and control system, and our data reduction pipeline are also described. The design goals of the camera-excellent imaging quality and throughput, low flexure and internal background, and 5 Hz on-axis guiding, are all realized and quantified.

  15. La variación temporal de las constantes fundamentales

    NASA Astrophysics Data System (ADS)

    Bersten, M.; Landau, S.; Vucetich, H.

    Las diferentes teorías que unifican las cuatro interacciones fundamentales coinciden en predecir variaciones temporales y espaciales de las constantes fundamentales pero difieren en la forma de esta variación. Las observaciones astronómicas y geofísicas permiten establecer cotas sobre la variación de dichas constantes. ésto nos proporciona una herramienta importante para testear las diferentes teorías. En particular, se utilizó el modelo de supercuerdas propuesto por Damour y Polyakov. Se obtuvieron límites sobre los parámetros libres de dicho modelo consistentes con un conjunto de datos astronómicos y geofísicos.

  16. LAS - LAND ANALYSIS SYSTEM, VERSION 5.0

    NASA Technical Reports Server (NTRS)

    Pease, P. B.

    1994-01-01

    The Land Analysis System (LAS) is an image analysis system designed to manipulate and analyze digital data in raster format and provide the user with a wide spectrum of functions and statistical tools for analysis. LAS offers these features under VMS with optional image display capabilities for IVAS and other display devices as well as the X-Windows environment. LAS provides a flexible framework for algorithm development as well as for the processing and analysis of image data. Users may choose between mouse-driven commands or the traditional command line input mode. LAS functions include supervised and unsupervised image classification, film product generation, geometric registration, image repair, radiometric correction and image statistical analysis. Data files accepted by LAS include formats such as Multi-Spectral Scanner (MSS), Thematic Mapper (TM) and Advanced Very High Resolution Radiometer (AVHRR). The enhanced geometric registration package now includes both image to image and map to map transformations. The over 200 LAS functions fall into image processing scenario categories which include: arithmetic and logical functions, data transformations, fourier transforms, geometric registration, hard copy output, image restoration, intensity transformation, multispectral and statistical analysis, file transfer, tape profiling and file management among others. Internal improvements to the LAS code have eliminated the VAX VMS dependencies and improved overall system performance. The maximum LAS image size has been increased to 20,000 lines by 20,000 samples with a maximum of 256 bands per image. The catalog management system used in earlier versions of LAS has been replaced by a more streamlined and maintenance-free method of file management. This system is not dependent on VAX/VMS and relies on file naming conventions alone to allow the use of identical LAS file names on different operating systems. While the LAS code has been improved, the original capabilities

  17. La edad de las familias Eos, Themis y Koronis

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, R.

    Las familias de asteroides son el producto de la disrupción colisional de objetos destruídos por impactos ocurridos en el cinturón principal. Las colisiones posteriores han modificado los tamaños y las órbitas de los miembros de estas familias, por lo que las distribuciones que vemos hoy en día pueden ser muy diferentes de aquellas producidas inmediatamente después de la fragmentación del objeto original. En esta hipótesis, puede ser difícil reconstruir la evolución colisional de la familia basándose sólo en las actuales distribuciones y puede ser necesario hacer ciertas suposiciones para obtener información sobre las condiciones iniciales. En este trabajo se deriva una estimación de la edad de las familias Eos, Themis y Koronis obtenida de una simulación de la evolución colisional de un cuerpo original teórico para cada familia usando un modelo de distribución para el cinturón propuesto por Gil-Hutton (1996).

  18. Safety of the Las Vegas left-turn display.

    PubMed

    Ozmen, Ozlem; Tian, Zong Z; Gibby, A Reed

    2014-01-01

    This paper provides a safety evaluation of a special protected/permitted left turn signal control (Las Vegas LT Display) that has been implemented in the urbanized area of Las Vegas, Nevada. The Las Vegas LT Display eliminates the yellow trap condition for leading approach in lead/lag operation. It provides protected only left turns during certain times of day by suppressing the permitted green ball and yellow ball displays. Before and after studies were conducted using the crash data from 10 intersections. Results from the analyses indicated that no obvious safety concerns due to use of the special display.

  19. The Land Analysis System (LAS) for multispectral image processing

    USGS Publications Warehouse

    Wharton, S. W.; Lu, Y. C.; Quirk, Bruce K.; Oleson, Lyndon R.; Newcomer, J. A.; Irani, Frederick M.

    1988-01-01

    The Land Analysis System (LAS) is an interactive software system available in the public domain for the analysis, display, and management of multispectral and other digital image data. LAS provides over 240 applications functions and utilities, a flexible user interface, complete online and hard-copy documentation, extensive image-data file management, reformatting, conversion utilities, and high-level device independent access to image display hardware. The authors summarize the capabilities of the current release of LAS (version 4.0) and discuss plans for future development. Particular emphasis is given to the issue of system portability and the importance of removing and/or isolating hardware and software dependencies.

  20. The role of groundwater chemistry in the transport of bacteria to water-supply wells

    USGS Publications Warehouse

    Harvey, R.W.; Metge, D.W.

    1999-01-01

    Static mini-columns and in situ injection and recovery tests were used to assess the effects of modest changes in groundwater chemistry upon the pH-dependence of bacterial attachment, a primary determinant of bacterial mobility in drinking water aquifers. In uncontaminated groundwater (<1 mg l-1 dissolved organic carbon, DOC), bacterial attachment to aquifer grain surfaces declined steadily from 93 to 20% in response to an increase in pH from 5.8 to 7.8. However, bacterial attachment in modestly-contaminated groundwater (4 mg l-1 DOC) was relatively insensitive to pH change from pH 3.5 to pH 8, as was bacterial attachment in uncontaminated groundwater amended with only ~3 mg l-1 of purified humic acid. Destruction by UV-oxidation of the DOC in contaminated groundwater partially restored the pH-dependence of bacterial attachment. Results from static column tests and from a small-scale (3.6 m) natural-gradient injection and recovery study suggest that low concentrations of surfactants can also substantively alter the attraction of groundwater bacteria for grain surfaces and, therefore can alter the transport of bacteria to water-supply wells. This phenomenon was pH-sensitive and dependent upon the nature of the surfactant. At pH 7.6, 200 mg l-1 of the non-ionic surfactant, Imbentin, caused a doubling of fractional bacterial attachment in aquifer-sediment columns, but had little effect under slightly acidic conditions (e.g. at pH 5.8). In contrast, 1 mg l-1 of linear alkylbenzene sulphonate (LAS) surfactant, a common sewage-derived contaminant, decreased the fractional bacterial attachment by more than 30% at pH 5.8, but had little effect at pH 7.3.Static mini-columns and in situ injection and recovery tests were used to assess the effects of modest changes in groundwater chemistry upon the pH-dependence of bacterial attachment, a primary determinant of bacterial mobility in drinking water aquifers. In uncontaminated groundwater (<1 mg l-1 dissolved organic carbon

  1. RadNet Air Data From Las Vegas, NV

    EPA Pesticide Factsheets

    This page presents radiation air monitoring and air filter analysis data for Las Vegas, NV from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

  2. An overview of the Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Lu, Yun-Chi

    1986-01-01

    An outline covering the history, development methodology, and major hardware/software components of the Land Analysis System (LAS) is presented. System support services including the Transportable Applications Executive (TAE), Catalog Manager, history files, and applications services are briefly described along with the general functional capabilities of the 224 available applications programs. Example interface menus are given and desired enhancements to the LAS system are listed.

  3. Actitudes de los candidatos y maestros de ciencias en servicio acerca del uso de las herramientas computadorizadas en las clases de ciencias

    NASA Astrophysics Data System (ADS)

    Bayuelo, Ezequiel

    Este estudio examino y comparo las actitudes de los candidatos a maestros de ciencias y los maestros de ciencias en servicio acerca de la utilizacion de las herramientas computadorizadas en las clases de ciencias. Tambien identifico y diferencio el uso que ellos dan a estas herramientas en las clases de ciencias. Este estudio presenta un diseno descriptivo exploratorio. Constituyeron la muestra trescientos diez sujetos que fueron candidatos a maestros de ciencias o maestros de ciencias en servicio. Para recoger los datos se construyo y valido un cuestionario de treinta y un itemes. Se utilizaron las pruebas estadisticas no parametricas Kruskal Wallis y Chi-cuadrado (test de homogeneidad) para establecer las diferencias entre las actitudes de los sujetos con relacion al uso de las herramientas computadorizadas en las clases de ciencias. Los hallazgos evidenciaron que son positivas y muy parecidas las actitudes de los candidatos a maestros y maestros en servicio hacia el uso de las herramientas computadorizadas. No hubo diferencias entre los candidatos y maestros en servicio en terminos de las actitudes de confianza y empatia hacia el uso de las herramientas computadorizadas en las clases de ciencias. En aspectos como el uso del banco de datos bibliografico Eric y el uso de las herramientas computadorizadas en actividades educativas como explorar conceptos, conceptuar, aplicar lo aprendido y hacer asignaciones hubo diferencias estadisticamente significativas entre los candidatos y los maestros en servicio. Al comparar las frecuencias observadas con las esperadas hubo mas maestros en servicio y menos candidatos que indicaron usar el anterior banco de datos y las herramientas computadorizadas en las mencionadas actividades educativas.

  4. Degradation and environmental risk of surfactants after the application of compost sludge to the soil

    SciTech Connect

    Gonzalez, M.M.; Martin, J.; Camacho-Munoz, D.; Santos, J.L.; Aparicio, I.

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Degradation of surfactants in soil amended with sewage sludge during 100 days. Black-Right-Pointing-Pointer Temperature influences on the degradation of the studied compounds. Black-Right-Pointing-Pointer Overall, the LAS degradation is faster than the NP compounds degradation. Black-Right-Pointing-Pointer Therefore, the LAS presented lower environmental risk than the NP compounds. - Abstract: In this work, the degradation of anionic and non-ionic surfactants in agricultural soil amended with sewage sludge is reported. The compounds analysed were: linear alkylbenzene sulphonates (LAS) with a 10-13 carbon alkylic chain, and nonylphenolic compounds (NPE), including nonylphenol (NP) and nonylphenol ethoxylates with one and two ethoxy groups (NP1EO and NP2EO). The degradation studies were carried out under winter (12.7 Degree-Sign C) and summer (22.4 Degree-Sign C) conditions in Andalusia region. The concentration of LAS was reduced to 2% of the initial concentration 100 day after sludge-application to the soil. The half-life time measured for LAS homologues were ranged between 4 and 14 days at 12.7 Degree-Sign C and between 4 and 7 days at 22.4 Degree-Sign C. With regard to NPE compounds, after 8 and 4 days from the beginning of the experiment at 12.7 and 22.4 Degree-Sign C, respectively, their concentration levels were increased to 6.5 and 13.5 mg/kg dm (dry matter) as consequence of the degradation of nonylphenol polyethoxylates. These concentration levels were reduced to 5% after 63 and 70 days for 12.7 Degree-Sign C and 22.4 Degree-Sign C, respectively. The half-life times measured for NPEs were from 8 to 16 days at 12.7 Degree-Sign C and from 8 to 18 days at 22.4 Degree-Sign C. Environmental risk assessment revealed that for LAS homologues no environment risk could be expected after 7 and 8 days of sludge application to the soil for 22.4 and 12.7 Degree-Sign C, respectively; however, potential toxic effects could be

  5. Las dificultades de sentir: el rol de las emociones en la estigmatización del VIH/SIDA

    PubMed Central

    MARZÁN-RODRÍGUEZ, Melissa; VARAS-DÍAZ, Nelson

    2009-01-01

    Resumen El Virus de Inmunodeficiencia Humana (VIH) y el Síndrome de Inmunodeficiencia Adquirida (SIDA) han sido motivo de estigmatización para las personas que viven con ellos. Esta estigmatización se ha estudiado consecuentemente desde la perspectiva de opiniones de agentes estigmatizantes. Estas opiniones han obviado sistemáticamente el rol de las emociones en el proceso de estigmatización. Llevamos a cabo este estudio con el propósito de identificar el rol de las emociones en el proceso de estigmatización de las personas que viven con el virus (PVVS) por parte de profesionales de la salud. Para lograr este objetivo utilizamos un diseño exploratorio y cualitativo en el cual utilizamos la técnica de entrevistas semiestructuradas a profundidad. La muestra estuvo compuesta por 80 profesionales de la salud y estudiantes de las siguientes especialidades: psicología, trabajo social, medicina y enfermería. Los resultados reflejaron la existencia de emociones asociadas al VIH/SIDA tales como pena, lástima, compasión, asco, fobia y miedo entre los/as profesionales y estudiantes que participaron. Las personas participantes evidenciaron la necesidad de controlar sus emociones al interactuar con PVVS. Los resultados apuntan a la necesidad de explorar aquellos factores que mediatizan las emociones, tales como el contexto social en que se manifiestan y ante quiénes se revelan, para lograr entender a cabalidad el estigma que rodea al VIH/SIDA. PMID:20212916

  6. 77 FR 1720 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting..., the U.S. Department of the Interior, Bureau of Land Management (BLM), Las Cruces District Resource... BLM Las Cruces District Office, 1800 Marquess Street, Las Cruces, NM 88005, from 10 a.m.-4 p.m....

  7. 77 FR 18858 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting..., the U.S. Department of the Interior, Bureau of Land Management (BLM), Las Cruces District Resource... Las Cruces District Office, 1800 Marquess Street, Las Cruces, NM 88005, from 10 a.m.-4 p.m. The...

  8. LAS: a software platform to support oncological data management.

    PubMed

    Baralis, Elena; Bertotti, Andrea; Fiori, Alessandro; Grand, Alberto

    2012-11-01

    The rapid technological evolution in the biomedical and molecular oncology fields is providing research laboratories with huge amounts of complex and heterogeneous data. Automated systems are needed to manage and analyze this knowledge, allowing the discovery of new information related to tumors and the improvement of medical treatments. This paper presents the Laboratory Assistant Suite (LAS), a software platform with a modular architecture designed to assist researchers throughout diverse laboratory activities. The LAS supports the management and the integration of heterogeneous biomedical data, and provides graphical tools to build complex analyses on integrated data. Furthermore, the LAS interfaces are designed to ease data collection and management even in hostile environments (e.g., in sterile conditions), so as to improve data quality.

  9. Navajo minettes in the Cerros de las Mujeres, New Mexico

    NASA Astrophysics Data System (ADS)

    Vaniman, D.; Laughlin, A. W.; Gladney, E. S.

    1985-06-01

    The Cerros de las Mujeres in west-central New Mexico are three mafic minette plugs that should be considered part of the Navajo volcanic fields on the central Colorado Plateau. This newly recognized occurrence extends the Navajo volcanic fields to the southeastern margin of the Colorado Plateau, within 45 km of the extensional tectonic setting in which the Mogollon ash-flow tuff cauldrons occur. The Cerros de las Mujeres provide additional evidence for contemporaneous sodic and potassic volcanism within the Navajo volcanic fields.

  10. The Las Vegas Sustainability Atlas: Modeling Place-based Interactions and Implications in the Las Vegas Valley Bioregion

    NASA Astrophysics Data System (ADS)

    Ego, H.; McCown, K.; Saghafi, N.; Gross, E.; Hunter, W.; Zawarus, P.; Gann, A.; Piechota, T. C.

    2014-12-01

    Las Vegas, Nevada, with 2 million residents and 40 million annual visitors, is one of the driest metropolitan environments of its size in the world. The metro imports nearly all of its resources, including energy, water and food. Rapid population increases, drought, and temperature increases due to climate change create challenges for planning resilient systems in the Las Vegas Valley. Because of its growth rate, aridity, Las Vegas, Nevada is a significant and relevant region for the study of the water, energy, food and climate nexus. Cities in the United States and the world are seeing increasing trends in urbanization and water scarcity. How does the water-energy-climate-food nexus affect each metropolitan area? How can this complex information be used for resiliency planning? How can it be related to the public, so they can understand the issues in a way that makes them meaningful participants in the planning process? The topic of our presentation is a 'resiliency atlas.' The atlas is a place-based model tested in Las Vegas to explore bioregional distinctiveness of the water-energy-climate-food nexus, including regional transportation systems. The atlas integrates the systems within a utilitarian organization of information. Systems in this place-based model demonstrate how infrastructure services are efficiently provided for the Las Vegas Valley population. This resiliency atlas can clarify how the nexus applies to place; and how it can be used to spur geographically germane adaption strategies. In the Las Vegas Valley, climate change (drought and high sustained temperatures) and population affect water, energy, and food systems. This clarity of a place based model can help educate the public about the resilience of their place, and facilitate and organize the planning process in the face of uncertainty.

  11. Solar Hot Water for a Motor Inn -- Las Vegas, Nevada

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Solar hot-water installation at motor inn in Las Vegas, Nevada is described in report containing descriptions of design, philosophy, operation of system and problems and solutions. Provides drawings of solar roof plan, operator's instructions, manufacturers' brochures and copy of acceptance report.

  12. Las Rocas Nos Cuentan (Rocks Tell Their Stories)

    ERIC Educational Resources Information Center

    Llerandi-Roman, Pablo A.

    2012-01-01

    Many Earth science lessons today still focus on memorizing the names of rocks and minerals. This led the author to develop a lesson that reveals the fascinating stories told by rocks through the study of their physical properties. He first designed the lesson for Puerto Rican teachers, hence its Spanish title: "Las Rocas Nos Cuentan Su Historia."…

  13. Experiencing Architecture: The Young People's Library Department in Las Vegas.

    ERIC Educational Resources Information Center

    Dixon, Joyce K.

    1991-01-01

    Describes the development of the Young People's Library in Las Vegas (Nevada) as a symbolic and literal bridge to the Lied Discovery Children's Museum. The roles in the design process of library administration, library personnel, and the architect are explored, and how this project addressed differences between the architect's artistic vision and…

  14. Reading "Las Meninas": An Ekphrastic Approach to Teaching "Don Quijote"

    ERIC Educational Resources Information Center

    Ortuno, Marian

    2012-01-01

    Reading and teaching "Don Quijote" present multiple challenges to twenty-first century students and instructors who are culturally and historically distanced from the seventeenth century. With "Las Meninas" serving as a visual lexicon for cuing correlative themes and events in "Don Quijote", the instructor, through an ekphrastic, interdisciplinary…

  15. EPA Sparks Local Business in Las Cruces, N.M.

    EPA Pesticide Factsheets

    DALLAS - (Feb. 29, 2016) The U.S. Environmental Protection Agency (EPA) is awarding a $300,000 small business contract to Vista Photonics, Inc. in Las Cruces, N.M. The company plans to develop an inexpensive, high-performance, portable air pollution

  16. Thermal expansion in metal/lithia-alumina-silica (LAS) composites

    NASA Astrophysics Data System (ADS)

    Wolff, E. G.

    1988-03-01

    Lithia-alumina-silica (LAS) with metallic dispersions offers a new approach toward near-zero, isotropic, thermal expansion composites. The metallic phase contributes a positive coefficient of thermal expansion (CTE) to the negative CTE of the glass/ceramic matrix. In addition, the metal will increase the electrical and thermal conductivities over those of the matrix alone. The LAS system offers tailorable negative CTEs and light weight compared to other negative CTE ceramics. The most negative CTE phase is crystalline β-eucryptite, whose proportion in an initially glassy matrix can be controlled by heat treatment. Dispersed metal powders were both hot-pressed and cold-pressed and sintered together with LAS matrices prepared by sol gel methods. Super Invar powder was studied for its minimal CTE mismatch, while titanium powders offered a compromise between light weight and low CTE. An ultralow-expansion (ULE) glass- and linear variable differential transducer (LVDT)-based differential dilatometer was developed for rapid screening of compositions, while a double-laser Michelson interferometer was used for precise near-zero CTE measurements. The reinforced β-eucryptite glass/ceramic matrix exhibited both a U-shaped ΔL/L curve with temperature and some thermal hysteresis, depending on the fabrication and heat treatment sequences. The temperature of the zero-CTE portion of this curve was found to change with increasing titanium powder content. Results are also given for mixtures of Super Invar powders in ULE glass and β-eucryptite matrices. Negative CTEs in a LAS matrix above ambient temperatures were more difficult to obtain than below, although the use of petalite (high-silica LAS) appears promising.

  17. [Biodegradation of LAS in the anaerobic water of a representative inlet of Lake Dianchi].

    PubMed

    Wang, Zhi; Tu, Xin-hai; Xiao, Bang-ding; Wu, Xing-qiang; Liu, Min; Chen, Xu-dong

    2008-08-01

    Biodegradation and degradation kinetics of anion-surfactant (LAS) in the anaerobic water of a representative inlet (Haihe River) of Lake Dianchi under different incubation conditions were studied by the 'river die-away' test method. The influences of temperature, pH, initial concentration of LAS, aeration condition and added nutrients (NH4Cl or NaH2PO4) on the biodegradation of LAS in the water were investigated. The results demonstrate that LAS can be biodegraded by microorganisms in the water and that the percentage of degradation of LAS was more than 95% after 26 d. The biodegradation of LAS fit the second kinetic model. Incubation temperature, initial concentration of LAS, aeration and added nutrients (NH4Cl or NaH2PO4) can all affect the biodegradation of LAS. When the incubation temperature increased from 10 degrees C to 25 degrees C, the biodegradation rate (p) of LAS increased from 0.21 d(-1) to 0.90 d(-1). The LAS degradation rate increased from 0.72 d(-1) under anaerobic condition to 1.97 d(-1) under continuous aeration condition. The increased initial concentrations of LAS lead to decrease of the biodegradation rate. NaH2PO4 accelerated the degradation of LAS but added NH4Cl instead inhibited degradation. In our experiment, pH value (7.05-9.44) had little influence on the biodegradation of LAS.

  18. Solar hot water system installed at Las Vegas, Nevada

    NASA Technical Reports Server (NTRS)

    1981-01-01

    A solar energy hot water system installed in a motor inn at Las Vegas, Nevada is described. The inn is a three story building with a flat roof for installation of the solar panels. The system consists of 1,200 square feet of liquid flat plate collectors, a 2,500 gallon insulated vertical steel storage tank, two heat exchangers, and pumps and controls. The system was designed to supply approximately 74 percent of the total hot water load.

  19. Ecological protection in the Las Tres Virgenes, Mexico, geothermal field

    SciTech Connect

    Zirahuen Ortega Varela, J.R.

    1996-12-31

    The programs of environmental protection designed by Comision Federal de Electricidad are described in a general way. These programs detect, avoid, soften and compensate the environmental impacts product of the exploration, construction and operation activities of the geothermal field Las Tres Virgenes, this field is in the buffer zone of the biosphere reserve {open_quotes}El Vizcaino{close_quotes} at the north of the State of Baja California Sur, Mexico.

  20. Geology of Las Vegas, Nevada, United States of America

    SciTech Connect

    Wyman, R.V.; Karakouzian, M. ); Bax-Valentine, V. ); Peterson, L.; Palmer, S. ); Slemmons, D.B.

    1993-03-01

    Las Vegas is one of the fastest growing cities in the US. Its regional geologic setting is in the Basin and Range geomorphic province and in the Sevier orogenic belt. The city itself lies in a broad north-south valley formed by coalescing alluvial fans and lake beds which give rise to several soil and foundation problems. Although destructive earthquakes have not occurred in the Las Vegas area in modern times, the record is very short. Major earthquakes could have taken place in the past when the area was unoccupied except for a few nomadic tribes. Studies are underway to better define the seismicity. Although the climate is hot and dry, flash flooding occurs frequently from late summer thunderstorms and torrential rains. The Regional Flood Control District is actively constructing retention basins and drainage improvements for diversion and protection from such floods. Water supply is a problem for the increasing population. The groundwater supply has long been overdrawn, and the allotment to Nevada under the Colorado River Compact will be completely utilized in the near future. Las Vegas has faced the problems of solid waste disposal, water treatment, rational water use, flooding and earthquakes - all of which are related to the unique geologic and geomorphic setting.

  1. GIS methodology for quantifying channel change in Las Vegas, Nevada

    USGS Publications Warehouse

    Buckingham, S.E.; Whitney, J.W.

    2007-01-01

    This study applies spatial analyses to examine the consequences of accelerated urban expansion on a hydrologic system over a period of 24 years. Three sets of historical aerial photos are used in a GIS analysis to document the geomorphic history of Las Vegas Wash, which drains the rapidly growing Las Vegas urban area in southern Nevada. New spatial techniques are introduced to make quantitative measurements of the erosion at three specific time intervals in the hydrologic evolution of the channel and floodplain. Unlike other erosion studies that use two different elevation surfaces to assess erosion, this study used a single elevation surface to remove systematic and nonsystemic elevation errors. The spatial analysis quantifies channel changes for discrete time periods, calculates erosion volumes, and provides a foundation to examine how the specific mechanisms related to urban expansion have affected Las Vegas Wash. The erosion calculated over 24 years is the largest documented sediment loss attributed to the effect of rapid urban growth. ?? 2007 American Water Resources Association.

  2. Port Risk Assessment Port of Ponce, Guayanilla, Yabucoa, and Las Mareas, Puerto Rico, After Action Report

    DTIC Science & Technology

    2000-02-10

    Port Assessment Ponce, Guayanilla, Yabucoa, and Las Mareas Port of Ponce, Guayanilla, Yabucoa, and Las Mareas , Puerto Rico, After Action Report...Introduction. A Port Risk Assessment was conducted for the port of Ponce, Guayanilla, Yabucoa, and Las Mareas , Puerto Rico (South Central...3. DATES COVERED 00-00-2000 to 00-00-2000 4. TITLE AND SUBTITLE Port Risk Assessment Port of Ponce, Guayanilla, Yabucoa, and Las Mareas

  3. Source Water Assessment for the Las Vegas Valley Surface Waters

    NASA Astrophysics Data System (ADS)

    Albuquerque, S. P.; Piechota, T. C.

    2003-12-01

    The 1996 amendment to the Safe Drinking Water Act of 1974 created the Source Water Assessment Program (SWAP) with an objective to evaluate potential sources of contamination to drinking water intakes. The development of a Source Water Assessment Plan for Las Vegas Valley surface water runoff into Lake Mead is important since it will guide future work on source water protection of the main source of water. The first step was the identification of the watershed boundary and source water protection area. Two protection zones were delineated. Zone A extends 500 ft around water bodies, and Zone B extends 3000 ft from the boundaries of Zone A. These Zones extend upstream to the limits of dry weather flows in the storm channels within the Las Vegas Valley. After the protection areas were identified, the potential sources of contamination in the protection area were inventoried. Field work was conducted to identify possible sources of contamination. A GIS coverage obtained from local data sources was used to identify the septic tank locations. Finally, the National Pollutant Discharge Elimination System (NPDES) Permits were obtained from the State of Nevada, and included in the inventory. After the inventory was completed, a level of risk was assigned to each potential contaminating activity (PCA). The contaminants of concern were grouped into five categories: volatile organic compounds (VOCs), synthetic organic compounds (SOCs), inorganic compounds (IOCs), microbiological, and radionuclides. The vulnerability of the water intake to each of the PCAs was assigned based on these five categories, and also on three other factors: the physical barrier effectiveness, the risk potential, and the time of travel. The vulnerability analysis shows that the PCAs with the highest vulnerability rating include septic systems, golf courses/parks, storm channels, gas stations, auto repair shops, construction, and the wastewater treatment plant discharges. Based on the current water quality

  4. 77 FR 77090 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated..., 4100 Dripping Springs Road, Las Cruces, NM, 88005 from 9 a.m.-4 p.m. The public may send...

  5. 78 FR 20354 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-04

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated below. DATES: The RAC will meet on April 23, 2013, at the BLM Las Cruces District Office Main...

  6. 78 FR 44590 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated below. DATES: The RAC will meet on August 22, 2013, at the BLM Las Cruces District Office...

  7. 78 FR 65356 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ... Bureau of Land Management Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting... of Land Management's (BLM) Las Cruces District Resource Advisory Council (RAC) will meet as indicated below. DATES: The RAC will meet on November 20, 2013, at the BLM Las Cruces District Office...

  8. 76 FR 35371 - Proposed Modification of the Las Vegas, NV, Class B Airspace Area; Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-17

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Modification of the Las Vegas, NV, Class B... information from airspace users and others, concerning a proposal to modify Class B airspace at Las Vegas, NV... Centennial Parkway, Las Vegas, NV 89149; (2) The meeting on Tuesday, August 23, 2011, will be held...

  9. La importancia de la protección de las playas

    EPA Pesticide Factsheets

    Las playas son una parte importante de la vida en Estados Unidos. Las playas ofrecen un sinnúmero de beneficios para el medio ambiente, actividades recreativas y la economía local. Aprenda la importancia de las playas y cómo protegerlas.

  10. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Las Vegas Intrastate Air...

  11. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Las Vegas Intrastate Air...

  12. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Las Vegas Intrastate Air...

  13. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Las Vegas Intrastate Air...

  14. 40 CFR 81.80 - Las Vegas Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Quality Control Regions § 81.80 Las Vegas Intrastate Air Quality Control Region. The Las Vegas Intrastate Air Quality Control Region (Nevada) has been revised to consist of the territorial area encompassed by... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Las Vegas Intrastate Air...

  15. Geological Mapping Using Legacy Geophysical Data in Las Vegas Valley

    NASA Astrophysics Data System (ADS)

    Donovan, D.; O'Donnell, J.; McLin, K.

    2014-12-01

    In 2008-2011, Clark County, Building Department contracted with Optim to collect 10,700 Reflection Microtremor (ReMi) 600 ft seismic lines that cover most of the metropolitan area of Las Vegas and other outlying communities such as Moapa, Laughlin, Primm, and Coyote Spring. The County completed their goal of characterizing seismic susceptibility of the top 100 ft and the results are posted at http://gisgate.co.clark.nv.us/openweb/. The research question of the authors is: What additional geologic information can be inferred from the data, either through reprocessing, cross correlation of drill hole data or additional data collection? An advantage of geophysical data is that it can be reprocessed to provide additional insight into the local geologic setting. The interpretation is also improved if combined with drill hole data and / or hydrologic information. It should be noted that there is also legacy geophysical data in limited areas collected by the USGS, primarily in conjunction with water well drilling, where some of the ReMi seismic data was collected. An unexpected result of the ReMi survey was a clear delineation of current and paleo channels in Laughlin, Moapa, and Las Vegas. The geometry of the paleochanel, of the Colorado River, is well away from the current position. however the signal is very similar to modern streams such as the Muddy River. Although the surficial geologic mapping in Las Vegas Valley was very detailed, and importantly, was performed prior to development; the new geophysical data provides better details of the lithologic properties of the units. That is it may be an excellent basis for remapping for specific properties related to engineering and hydrologic modeling.

  16. El libro del Relogio del Palacio de las Horas

    NASA Astrophysics Data System (ADS)

    Morales, J. D.

    2009-08-01

    This paper resume the investigation entitled ``El libro del Relogio del Palacio de las Horas''. That consist in an edition of the original text of the book of the Clock of the Palace of the Hours from the Books of the knowledge of Astronomy of Alfonso X (Manuscript 156, Complutense University). And a description of the astronomical functionality of the Clock of the Palace of the Hours. It includes a geometric description of the positional astronomy on which the operation of the Palace is based.

  17. Revision curricular a partir de un analisis comparativo de las discrepancias en los curriculos de una escuela de optometria en Puerto Rico con las competencias requeridas para las agencias de revalida y acreditacion 2004

    NASA Astrophysics Data System (ADS)

    Rivera Pacheco, Andres

    El proposito de esta investigacion, un estudio cualitativo de caso, fue comparar y contrastar el curriculo vigente de la Escuela de Optometria de la UIAPR con las competencias y estandares requeridos por las agencias de acreditacion y de revalida. Con este proposito, decidimos realizar una revision y un analisis de documentos: el prontuario de cada uno de los cursos de los curriculos implantados en el 1993 y en el 2001; las competencias y estandares establecidos por las agencias de revalida y de acreditacion; y las estadisticas en las que se analiza el porcentaje de estudiantes que aprueban cada una de las partes de los examenes de revalida entre el 1998 al 2003. Se realizaron entrevistas dirigidas para dar apoyo y complementar la revision y el analisis de estos documentos. Los participantes de las entrevistas fueron tres estudiantes de la clase de optometria del 2004 (ultima clase del curriculo del 1993); tres estudiantes de la clase de optometria del 2005 (primera clase graduanda del curriculo vigente) y tres profesores y/o directores de los Departamentos de Ciencias Basicas, Ciencias Clinicas y Cuidado al Paciente. Esta investigacion se enmarco en el modelo de evaluacion curricular de discrepancia de Malcolm Provus y en el modelo de desarrollo basado en competencias. Uno de los hallazgos mas importantes del estudio es que los cambios que se implantaron al curriculo del 2001 no han logrado que los estudiantes mejoren su ejecucion en los examenes de revalida. Por otro lado, se encontro que el curriculo vigente atiende completamente los estandares de la practica de Optometria, pero no las competencias. Esta informacion fue validada mediante el uso de una tabla de cotejo para el analisis de los cursos y de la informacion obtenida de las entrevistas. El estudio determina y concluye que existen discrepancias entre los prontuarios de los cursos del curriculo y las competencias requeridas por la agencia de revalida. Segundo, que el Departamento de Ciencias Basicas es el

  18. Decomposition of cumyl hydroperoxide in the presence of sulphonated silica in a flow-type system

    SciTech Connect

    Shelpakova, N.A.; Ioffa, A.F.

    1993-12-31

    An investigation has been made of the decomposition of cumyl hydroperoxide (CHP) in the presence of silica-based sulphocationites in a flow-type system. It was established that the given specimens are effective catalysts for the decomposition of CHP into phenol and acetone. It was shown that, in the course of the process, no irreversible poisoning of the surface of the catalyst by the products of CHP decomposition occurs. Data of chromatographic analysis of the products of CHP decomposition in the presence of sulphuric acid and silica-based sulphocationites are given.

  19. Potent inhibition of human immunodeficiency virus by MDL 101028, a novel sulphonic acid polymer.

    PubMed

    Taylor, D L; Brennan, T M; Bridges, C G; Mullins, M J; Tyms, A S; Jackson, R; Cardin, A D

    1995-10-01

    MDL 101028, a novel biphenyl disulphonic acid urea co-polymer was designed and synthesised as a heparin mimetic. This low molecular weight polymer showed potent inhibition of human immunodeficiency virus type 1 (HIV-1) replication in a number of host-cell/virus systems, including primary clinical isolates of the virus cultured in human peripheral blood mononuclear cells (PBMCs). When compared with the heterogeneous polysulphated molecules, heparin and dextran sulphate, this chemically defined compound showed equivalent antiviral activity with 50% inhibitory concentrations (IC50s) in the range 0.27-3.0 micrograms/ml in the host-cell/virus systems tested. MDL 101028 also inhibited the replication of HIV type 2 and the simian immunodeficiency virus (SIV), as well as HIV-1 variants resistant to reverse transcriptase inhibitors. Virus growth was blocked when exposure of T-lymphocytes to MDL 101028 was restricted to the virus absorption stage, or even in whole blood conditions. MDL 101028 did not irreversibly inactivate virions, and in contrast to heparin, did not inhibit the attachment of radiolabelled HIV-1 to CD4+ T-cells. MDL 101028 blocked HIV-induced cell-to-cell fusion and this activity appears to explain the mechanism of its antiviral action. The antiviral evaluation of discrete oligomer molecules of MDL 101028 showed that a polymer chain length of six repeating units had optimal potency. The lack of anticoagulant properties and significant antiviral activity in whole blood may allow the development of MDL 101028 as a treatment of HIV infections.

  20. Unnatural pregnancy deaths in Las Vegas: A descriptive study.

    PubMed

    Mahesan Paul, Anthea B; Simms, Lary; Paul, Abraham Ebenezer; Yorke, Jojo; Saroya, Tarnjot; Schmidseder, Christopher; Mahesan, Andrew A; Mahesan, Arnold M

    2016-11-01

    This study reports descriptive data assessing the prevalence of various risk factors and associations among pregnancy-related death by unnatural causes (PRUD), namely suicide, homicide and accidental causes in the city of Las Vegas. In 7215 women referred for autopsy, results showed PRUD 0.1% (n = 37) was more common in the Caucasian race 45.9% (n = 17), and ages 20-30 years 43.2% (n = 16). We also identified high prevalence of mental illness 51.3% (n = 19) and low prenatal care 37.8% (n = 14), particularly in our suicide cohort 100.0% (n = 13), and 15.3% (n = 2) respectively. Our study demonstrates the first investigation to identify the relationship between mental illness, particularly mood and substance disorders with pregnancy-related unnatural death.

  1. Proteus aircraft over Las Cruces International Airport in New Mexico.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  2. Proteus aircraft low-level flyby at Las Cruces Airport.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  3. Proteus in flight over mountains near Las Cruces, New Mexico.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  4. City of Las Vegas Plug-in Hybrid Electric Vehicle Demonstration Program

    SciTech Connect

    2013-12-31

    The City of Las Vegas was awarded Department of Energy (DOE) project funding in 2009, for the City of Las Vegas Plug-in Hybrid Electric Vehicle Demonstration Program. This project allowed the City of Las Vegas to purchase electric and plug-in hybrid electric vehicles and associated electric vehicle charging infrastructure. The City anticipated the electric vehicles having lower overall operating costs and emissions similar to traditional and hybrid vehicles.

  5. Explicación de las disparidades raciales en la salud neonatal en Brasil*

    PubMed Central

    Nyarko, Kwame A.; López-Camelo, Jorge; Castilla, Eduardo E.; Wehby, George L.

    2015-01-01

    Objetivos. Buscamos cuantificar la manera en que los efectos socioeconómicos, demográficos, geográficos y de atención de salud explican las disparidades raciales en las tasas de bajo peso al nacer y prematuridad en Brasil. Métodos. Utilizamos una muestra de 8 949 niños nacidos entre 1995 y el 2009 en 15 ciudades y 7 provincias de Brasil. Nos centramos en las disparidades en la prevalencia de bajo peso al nacer (< 2 500 g) y prematuridad (< 37 semanas de gestación) en recién nacidos de ascendencia solo africana o mezclada con otras ascendencias y de ascendencia solo europea. Usamos un modelo de descomposición para cuantificar la contribución de los factores conceptualmente pertinentes a esas disparidades. Resultados. El modelo permitió explicar entre 45% y 94% de las disparidades en cuanto al bajo peso al nacer y entre 64% y 94% de las disparidades en cuanto a la prematuridad entre los grupos de ascendencia africana y de ascendencia europea. Las diferencias en el uso de atención prenatal y en la ubicación geográfica fueron los factores más importantes, seguidos por las diferencias socioeconómicas. El modelo permitió explicar la mayoría de las disparidades en los recién nacidos de ascendencia africana mezclada y parte de las disparidades en los de ascendencia solo africana. Conclusiones. En las políticas públicas para mejorar la salud infantil se deben abordar las diferencias en cuanto a la atención prenatal y la ubicación geográfica a fin de reducir las disparidades en materia de salud entre los recién nacidos de ascendencia africana y los de ascendencia europea en Brasil.

  6. Stationary Phase-Specific Virulence Factor Overproduction by a lasR Mutant of Pseudomonas aeruginosa

    PubMed Central

    Cabeen, Matthew T.

    2014-01-01

    Secreted virulence factors of the human pathogen Pseudomonas aeruginosa are often under quorum sensing control. Cells lacking the quorum-sensing regulator LasR show reduced virulence factor production under typical laboratory conditions and are hypo-virulent in short-term animal infection models, yet lasR mutants are frequently associated with long-term infection in cystic fibrosis patients. Here, I show that in stationary-phase or slow-growth conditions, lasR cells continuously and strongly produce the important virulence factor pyocyanin while wild-type cells do not. Pyocyanin overproduction by lasR cells is permitted by loss of repression by RsaL, a LasR-dependent negative regulator. lasR cells also contribute pyocyanin in mixed cultures, even under “cheating” conditions where they depend on their wild-type neighbors for nutrients. Finally, some clinical P. aeruginosa isolates with lasR mutations can overproduce pyocyanin in the laboratory. These results imply that slow-growing clinical populations of lasR cells in chronic infections may contribute to virulence by producing pyocyanin under conditions where lasR+ cells do not. PMID:24533146

  7. Las propiedades de las estrellas extrañas en el marco de una nueva ecuación de estado para la materia extraña

    NASA Astrophysics Data System (ADS)

    Lugones, G.; Benvenuto, O. G.

    Se estudian las propiedades generales de las estrellas constituídas por materia extraña (ME) en el marco de una nueva ecuación de estado (EOS) en la que consideramos la masa de los quarks como dependiente del número medio de bariones por unidad de volumen. Se asume esta dependencia de forma que los quarks sean livianos (pesados) a densidades altas (bajas). En esta aproximación, la EOS de la ME es similar a la predicha por el modelo de la Bolsa del MIT, pero es significativamente mas dura a bajas densidades. Esta propiedad modifica las propiedades de las estrellas extrañas en forma notable. Encontramos que, con esta nueva EOS, los objetos pueden ser más masivos que en el caso de la EOS de la bolsa del MIT y que, además, pueden presentar mayores redshifts gravitatorios en hasta un 10%. En el caso de las oscilaciones radiales de estos objetos, calculamos la relación período vs. redshift gravitacional y encontramos una expresión analítica simple para el caso de las oscilaciones de objetos de baja masa. Encontramos que, aún con hipótesis muy diferentes en cuanto a la ecuación de estado de la materia extraña, las propiedades generales de estos objetos no se ve afectada en forma fundamental, y, por lo tanto, no deberían ser muy diferentes de las aquí expuestas.

  8. Las Vegas Basin Seismic Response Project: Measured Shallow Soil Velocities

    NASA Astrophysics Data System (ADS)

    Luke, B. A.; Louie, J.; Beeston, H. E.; Skidmore, V.; Concha, A.

    2002-12-01

    The Las Vegas valley in Nevada is a deep (up to 5 km) alluvial basin filled with interlayered gravels, sands, and clays. The climate is arid. The water table ranges from a few meters to many tens of meters deep. Laterally extensive thin carbonate-cemented lenses are commonly found across parts of the valley. Lenses range beyond 2 m in thickness, and occur at depths exceeding 200 m. Shallow seismic datasets have been collected at approximately ten sites around the Las Vegas valley, to characterize shear and compression wave velocities in the near surface. Purposes for the surveys include modeling of ground response to dynamic loads, both natural and manmade, quantification of soil stiffness to aid structural foundation design, and non-intrusive materials identification. Borehole-based measurement techniques used include downhole and crosshole, to depths exceeding 100 m. Surface-based techniques used include refraction and three different methods involving inversion of surface-wave dispersion datasets. This latter group includes two active-source techniques, the Spectral Analysis of Surface Waves (SASW) method and the Multi-Channel Analysis of Surface Waves (MASW) method; and a new passive-source technique, the Refraction Mictrotremor (ReMi) method. Depths to halfspace for the active-source measurements ranged beyond 50 m. The passive-source method constrains shear wave velocities to 100 m depths. As expected, the stiff cemented layers profoundly affect local velocity gradients. Scale effects are evident in comparisons of (1) very local measurements typified by borehole methods, to (2) the broader coverage of the SASW and MASW measurements, to (3) the still broader and deeper resolution made possible by the ReMi measurements. The cemented layers appear as sharp spikes in the downhole datasets and are problematic in crosshole measurements due to refraction. The refraction method is useful only to locate the depth to the uppermost cemented layer. The surface

  9. A Total Water Management Analysis of the Las Vegas Wash Watershed, Nevada

    EPA Science Inventory

    Climate change, land use change, and population growth are fundamental factors affecting future hydrologic conditions in streams, especially in arid regions with scarce water resources. Located in the arid southwest, Las Vegas Valley located within the Las Vegas Wash watershed is...

  10. Problem-Solving in Las Vegas: Students Are Building Skills and a Global Network.

    ERIC Educational Resources Information Center

    Budd, Gregory; Curry, Don

    1995-01-01

    Describes a project initiated at Silverado High School in Las Vegas, where students from Las Vegas and schools across the United States monitor the levels of radon in the atmosphere. Enables students to learn first hand about the collection, analysis, and interpretation of scientific data and to network with other students from the United States…

  11. 78 FR 43772 - Modification of Class B Airspace; Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-22

    ...., long. 114 51'13'' W.); thence counterclockwise along the 15 DME arc to the point of beginning. Area D... modifies the Las Vegas, NV, Class B airspace area to ensure the containment of large turbine-powered... midair collision in the Las Vegas, NV, terminal area. DATES: Effective Date: 0901 UTC, August 22,...

  12. Report: EPA Needs to Improve Physical Security at Its Offices in Las Vegas, Nevada

    EPA Pesticide Factsheets

    Report #10-P-0059, February 3, 2010. EPA needs to improve physical security at its Las Vegas facilities. The Las Vegas Finance Center’s (LVFC’s) server room and other key areas are susceptible to unauthorized access by personnel not a part of LVFC.

  13. FLS2 from Solanum tuberosum have interaction with FlaLas from Candidatus Liberibacter asiaticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus’ (Las) is a Gram-negative and phloem-limited alphaproteobacterium. Las attacks all citrus species and citrus hybrids in the genus of Citrus and other relatives, and causes a systemic disease. Currently, control of this devastating disease is extremely difficult sinc...

  14. REMOTE SENSING OF PERCHLORATE EFFECTS ON SALT CEDAR PRELIMINARY RESULTS FROM THE LAS VEGAS WASH

    EPA Science Inventory



    Sodium Perchlorate and ammonium Perchlorate, major components of solid rocket fuel, have been manufactured in the Las Vegas Valley immediately up gradient from the Las Vegas Wash, since 1945 and 1956, respectively. Measurements of emerging ground water quality in the vici...

  15. 75 FR 57289 - Notice of Inventory Completion: Pioneer Historical Society of Bent County, Las Animas, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-20

    ... National Park Service Notice of Inventory Completion: Pioneer Historical Society of Bent County, Las Animas... of an inventory of human remains in the control of the Pioneer Historical Society of Bent County, Las... Society of Bent County professional staff in consultation with representatives of the Apache Tribe...

  16. La Noche de las Brujas Module. Nivel Primario. [The Night of the Witches Module. Primary Level.

    ERIC Educational Resources Information Center

    Espinoza, Delia

    La Noche de las Brujas (Halloween) is the topic of this primary level unit. The objectives are to enable the child to: (1) draw scenery, using his imagination, about witches, castles, and devils; (2) write compositions on witches, devils, and Halloween; (3) explain the story "La Noche de las Brujas"; (4) tell about any adventures or…

  17. LasDamas Mock Galaxy Catalogs for SDSS

    NASA Astrophysics Data System (ADS)

    McBride, Cameron; Berlind, A.; Scoccimarro, R.; Wechsler, R.; Busha, M.; Gardner, J.; van den Bosch, F.

    2009-01-01

    The statistical strength of galaxy redshift surveys, such as the Sloan Digital Sky Survey (SDSS), have ushered us into the era of precision measurements of galaxy clustering. We are now fitting physical models to measured clustering statistics. Galaxy clustering is thus in a position to directly constrain cosmological and galaxy formation theories. This paradigm shift from qualitative to quantitative demands that we understand the statistical and systematic errors in our measurements. Moreover, we must quantify the theoretical uncertainties in our models, which are no longer clearly sub-dominant to observational errors. We address this emerging need with the LasDamas project (LArge Suite of DArk MAtter Simulations) by producing an unprecedented number of independent and realistic mock galaxy catalogs. To date, we have run over 100 independent N-body realizations using a fixed cosmology and initialized using 2nd order Lagrangian perturbation theory. We populate overdensities of dark matter using the halo occupation distribution framework, designed to match both small and large scale clustering of the observed SDSS data. A series of mock galaxy catalogs matching the geometry of the final SDSS release (DR7) are created over a wide luminosity range to correspond to Main and LRG volume-limited samples. We include important observational effects, such as redshift distortions and fiber collisions. These galaxy mocks are publicly available.

  18. Quorum-Sensing-Negative (lasR) Mutants of Pseudomonas aeruginosa Avoid Cell Lysis and Death

    PubMed Central

    Heurlier, Karin; Dénervaud, Valérie; Haenni, Marisa; Guy, Lionel; Krishnapillai, Viji; Haas, Dieter

    2005-01-01

    In Pseudomonas aeruginosa, N-acylhomoserine lactone signals regulate the expression of several hundreds of genes, via the transcriptional regulator LasR and, in part, also via the subordinate regulator RhlR. This regulatory network termed quorum sensing contributes to the virulence of P. aeruginosa as a pathogen. The fact that two supposed PAO1 wild-type strains from strain collections were found to be defective for LasR function because of independent point mutations in the lasR gene led to the hypothesis that loss of quorum sensing might confer a selective advantage on P. aeruginosa under certain environmental conditions. A convenient plate assay for LasR function was devised, based on the observation that lasR mutants did not grow on adenosine as the sole carbon source because a key degradative enzyme, nucleoside hydrolase (Nuh), is positively controlled by LasR. The wild-type PAO1 and lasR mutants showed similar growth rates when incubated in nutrient yeast broth at pH 6.8 and 37°C with good aeration. However, after termination of growth during 30 to 54 h of incubation, when the pH rose to ≥ 9, the lasR mutants were significantly more resistant to cell lysis and death than was the wild type. As a consequence, the lasR mutant-to-wild-type ratio increased about 10-fold in mixed cultures incubated for 54 h. In a PAO1 culture, five consecutive cycles of 48 h of incubation sufficed to enrich for about 10% of spontaneous mutants with a Nuh− phenotype, and five of these mutants, which were functionally complemented by lasR+, had mutations in lasR. The observation that, in buffered nutrient yeast broth, the wild type and lasR mutants exhibited similar low tendencies to undergo cell lysis and death suggests that alkaline stress may be a critical factor providing a selective survival advantage to lasR mutants. PMID:15995202

  19. Managing Floods and Resources at the Arroyo Las Positas

    SciTech Connect

    Sanchez, L; Van Hattem, M; Mathews, S

    2002-03-05

    Engineers and water resource professionals are challenged with protecting facilities from flood events within environmental resource protection, regulatory, and economic constraints. One case in point is the Arroyo Las Positas (ALP), an intermittent stream that traverses the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. Increased runoff from post-drought rainfall, upstream development, and new perennial discharges from LLNL activities have resulted in increased dry weather flows and wetland vegetation. These new conditions have recently begun to provide improved habitat for the federally threatened California red-legged frog (Rana aurora draytonii; CRLF), but the additional vegetation diminishes the channel's drainage capacity and increases flood risk. When LLNL proposed to re-grade the channel to reestablish the 100-year flood capacity, traditional dredging practices were no longer being advocated by environmental regulatory agencies. LLNL therefore designed a desilting maintenance plan to protect LLNL facility areas from flooding, while minimizing impacts to wetland resources and habitat. The result was a combination of structural upland improvements and the ALP Five Year Maintenance Plan (Maintenance Plan), which includes phased desilting in segments so that the entire ALP is desilted after five years. A unique feature of the Maintenance Plan is the variable length of the segments designed to minimize LLNL's impact on CRLF movement. State and federal permits also added monitoring requirements and additional constraints on desilting activities. Two years into the Maintenance Plan, LLNL is examining the lessons learned on the cost-effectiveness of these maintenance measures and restrictions and reevaluating the direction of future maintenance activities.

  20. LAS degradability by marine biofilms derived from seawater in Spain and Sweden.

    PubMed

    Mauffret, A; Gillan, D C; Eriksson, K M; Rottiers, A; Blasco, J; Temara, A

    2011-07-01

    Marine biofilms were established on glass beads with or without deliberate pre-exposure to LAS (20 μg/L) in Spain (Cadiz) and Sweden (Kristineberg). The ability of each community to mineralize LAS (100 μg/L) was then assessed in biometers at four experimental temperatures (between 6 and 21°C). Genetic diversity and biomass of the biofilms were assessed by genetic fingerprinting (DGGE) and direct bacterial counts. With biofilms from Sweden, where LAS was not detected in seawater (n = 3), deliberate pre-exposure to LAS resulted in lower genetic diversity and higher mineralization rate constant; however, with biofilms from Spain, where 6.4 ± 3.9 μgLAS/L (n = 3) was measured during the colonization, pre-exposure did not affect the bacterial community. Bacterial acclimation therefore appeared to have been induced at environmental concentrations < 6 μgLAS/L. Environmental pre-exposure was not a pre-requisite for featuring the full consortia of LAS degraders in the biometers. The mineralization rate was described using an Arrhenius equation at experimental temperatures within the typical annual range; however, they departed from this model below this range.

  1. Orion Capsule and Launch Abort System (LAS) installed in the NASA Glenn 8x6 Supersonic Wind Tunnel f

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Orion Capsule and Launch Abort System (LAS) installed in the NASA Glenn 8x6 Supersonic Wind Tunnel for testing. This test is an Aero Acoustic test of the LAS. Pictured is the calibration of the model's angle of attack

  2. SENSORY REACTIONS OF NASAL PUNGENCY AND ODOR TO VOLATILE ORGANIC COMPOUNDS: THE ALKYLBENZENES

    EPA Science Inventory

    Research assessed the independent contribution of the trigeminal and olfactory nerves to the detection of airborne chemicals by measuring nasal detection thresholds in subjects clinically diagnosed as lacking a functional sense of smell (anosmics) and in matched normal controls (...

  3. Identification of long-chain isoprenoid alkylbenzenes in sediments and crude oils

    NASA Astrophysics Data System (ADS)

    Sinninghe Damsté, Jaap S.; Kock-van Dalen, A. C.; de Leeuw, Jan W.

    1988-11-01

    A series of novel methylated phytanylbenzenes (phytanylbenzene, 1-methyl-3-phytanylbenzene, 1,4-dimethyl-2-phytanylbenzene, 1,2-dimethyl-4-phytanylbenzene and 1,2,4-trimethyl-5-phytanylbenzene) have been identified in sediment extracts and oils ranging in age from Miocene to Permian. Identifications were based on comparison of mass spectra and Chromatographie data of synthetic methylated phytanylbenzenes with those of geologically occurring methylated phytanylbenzenes and by coinjections with the standards. Although methylated phytanylbenzenes are structurally related to the methylated 2-methyl-2-(4,8,12-trimethyltridecyl)chromans, components also present in the samples studied, the former do not appear to be the diagenetic derivatives of the latter. The methylated phytanylbenzenes are thought to be derived diagenetically from isoprenoid quinones or may represent a direct biosynthetic origin from specific archaebacteria.

  4. High resolution electronic spectroscopy of three n-alkylbenzenes: ethyl-, propyl-, and butylbenzene

    NASA Astrophysics Data System (ADS)

    Borst, David R.; Joireman, Paul W.; Pratt, David W.; Robertson, Evan G.; Simons, John P.

    2002-04-01

    Rotationally resolved S1-S0 fluorescence excitation spectra of ethylbenzene, two conformers of n-propylbenzene, and two conformers of n-butylbenzene have been observed and assigned. The data obtained provide information about the equilibrium properties of each molecule, including their geometries in the S1-S0 states, their electronic distributions, and their dynamical behavior following the absorption of light. Trans structures are found to have S1 states that are 1Lb in character with relatively long fluorescence lifetimes. Gauche structures are found to have S1 states that are mixed (1Lb/1La) in character with relatively short fluorescence lifetimes. Possible reasons for these differences in properties are discussed.

  5. Natural bioreclamation of alkylbenzenes (BTEX) from a gasoline spill in methanogenic groundwater. Book chapter

    SciTech Connect

    Wilson, J.T.; Kampbell, D.H.; Armstrong, J.

    1994-01-01

    A spill of gasoline from underground storage tanks (USTS) at the Sleeping Bear Dunes National Lakeshore in Benzie County, Michigan, produced a plume of contamination that reached the banks of the Platte River. The plume was short (70 feet) and it had a short residence time (5 to 53 weeks). The plume was in transmissive glacial sands and gravels. The groundwater is cold (10 to 11 C), hard (alkalinity 200 to 350 milligrams/L), and well buffered (pH 6.1 to 7.6). Along the most contaminated flow path, methanogenesis, nitrate reduction, sulfate reduction, iron reduction, and oxygen respiration accepted enough electrons to destroy 30, 14, 4.2, 1.1, and 0.8 milligrams/L of benzene, toluene, ethylbenzene, and xylenes (BTEX compounds) respectively. The actual concentration of BTEX compounds consumed was 42 milligrams/L.

  6. 78 FR 32644 - Las Vegas Wash Hydro LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ... Energy Regulatory Commission Las Vegas Wash Hydro LLC; Notice of Preliminary Permit Application Accepted..., 2012, Las Vegas Wash Hydro LLC, filed an application for a preliminary permit, pursuant to section 4(f) of the Federal Power Act (FPA), proposing to study the feasibility of the Las Vegas...

  7. 76 FR 37034 - Proposed Modification of the Las Vegas, NV, Class B Airspace Area; Public Meetings; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-24

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Modification of the Las Vegas, NV, Class B... of June 17, 2011, concerning a proposal to modify Class B airspace at Las Vegas, NV. The document... Gough, Manager, Airspace and Procedures, and Bill Ruggiero, Support Manager Las Vegas, TRACON,...

  8. 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...

  9. 78 FR 2646 - Proposed Modification of Class B Airspace; Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-14

    ... FR 65332) closed on December 26, 2012, is reopened until February 13, 2013. ADDRESSES: Send comments... of Class B Airspace; Las Vegas, NV'' (77 FR 65332). The FAA requested that comments on that...

  10. Double star images taken by HST WFPC and Las Campanas Observatory

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Comparison of the same area of sky (a double star) taken by the Hubble Space Telescope (HST) wide field planetary camera (WFPC) and ground-based image taken from the Las Campanas Observatory, Carnegie Institute of Washington.

  11. 76 FR 61379 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ... public land management in New Mexico. Planned agenda items include a welcome and introduction of new... concerns in the BLM Las Cruces District and future project work for the RAC. A half-hour public...

  12. Terrestrial risk assessment for linear alkyl benzene sulfonate (LAS) in sludge-amended soils.

    PubMed

    de Wolf, W; Feijtel, T

    1998-03-01

    A comparison of the estimated environmental concentration and the effect concentrations (in the laboratory or field) in the receiving compartment form the basis of environmental risk assessments. This paper reviews processes that critically influence the fate of LAS in the terrestrial environment. Concentrations of LAS in sludge are quite high due to sorption to primary sludge, precipitation of Ca and Mg-salts of LAS, and lack of biodegradation under anaerobic digestion. This implies that when sludge is applied to soil e.g. as a fertilizer, considerable amounts of this important surfactant may enter the terrestrial environment. Influence of aerobic situations on LAS concentrations during sludge storage needs further research to allow incorporation into the risk assessment. Aerobic biodegradation in soil is considered the most important removal mechanism of LAS loading to the terrestrial environment through sludge-amendment. Sorption plays a role in determining the residence time of a chemical in the soil, hereby enabling more time for biodegradation to occur. In addition, sorption may affect the expression of effects of surfactants towards benthic and soil dwelling organisms and plants. Another factor that needs further attention is the form of LAS in the environment, which is not similar to the commercial material applied in detergents. The differential sorption and biodegradation of the LAS components lead to a shift in the alkyl chain length (homologue), and phenylisomer distribution towards increased hydrophobicity. Also, occurrence of Ca/Mg-salts in the environment versus the Na-salt for the commercial material critically impacts the extrapolation of effects data obtained in lab studies (mostly performed with the commercial material) to the field. The literature data were used in combination with strategies and methods provided by the European Union Technical Guidance Document in support of risk assessment of new and notified substances (1996) for the

  13. Best Practices Case Study: Pulte Homes and Communities of Del Webb, Las Vegas Division

    SciTech Connect

    2009-10-01

    Case study of Pulte Homes Las Vegas Division, who certified nearly 1,200 homes to the DOE Builders Challenge between 2008 and 2012. All of the homes by Las Vegas’ biggest builder achieved HERS scores of lower than 70, and many floor plans got down to the mid 50s, with ducts located in sealed attics insulated along the roof line, advanced framing, and extra attention to air sealing.

  14. LANDSAT-D assessment system library computer compatible tape (LASLIB-CCT/LAS-CCT)

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The format for computer compatible tapes containing thematic mapper archival data and product data generated by the LANDSAT-D Assessment System (LAS). These data tapes are engineering products developed primarily for LAS internal use to assist in the early evaluation of thematic mapper data quality and ground data processing algorithms during the limited period of one year following the launch of LANDSAT-D.

  15. Review on the fate of emerging contaminants during sludge anaerobic digestion.

    PubMed

    Stasinakis, Athanasios S

    2012-10-01

    Several research papers have been published during the last years investigating the occurrence, fate and effects of emerging contaminants (ECs) on sludge anaerobic digestion (AD). Literature review revealed that research has been mainly focused on specific groups of compounds (linear alkylbenzene sulphonates, nonylphenol ethoxylates, some pharmaceuticals, estrogens, phthalates), while there are fewer or no data for others (personal care products, perfluorinated compounds, brominated flame retardants, organotins, benzotriazoles, benzothiazoles, nanoparticles). AD operational parameters (sludge residence time, temperature), sludge characteristics (type of sludge, adaptation on the compound), physicochemical properties of ECs and co-metabolic phenomena seem to affect compounds' biodegradation. The use of sludge pretreatment methods does not seem to enhance ECs removal; whereas encouraging results have been reported when AD was combined with other treatment methods. Future efforts should be focused on better understanding of biotransformation processes and sorption phenomena occurred in anaerobic digesters, as well as on identification of (bio)transformation products.

  16. Exposure of the marine deposit feeder Hydrobia ulvae to sediment spiked with LAS congeners.

    PubMed

    Mauffret, A; Temara, A; Blasco, J

    2010-05-01

    The lethal and sub-lethal toxicity of LAS congeners to the mollusc gastropod Hydrobia ulvae were assessed in spiked sediment bioassays. This complements the little knowledge available to date on mixture effects in the sediment compartment. The LAS homologues joint effect was concentration additive ([summation operator]TU(i) = 0.8-1). As opposed to the 10-d LC10 based on the sediment associated LAS concentration (91-330 mg/kg) which was independent of the homologue chain length, the LC10 based on the dissolved LAS fraction (0.804-0.068 mg/L) decreased as the homologue chain length increased from 10 to 13 carbons. The quantitative structure-activity relationship (QSAR) derived from these data was log (1/LC10 (mol/L)) = 0.64 log K(ow) + 4.40 (n = 5; r(2) = 0.76; s = 0.24). It showed an apparent higher toxicity compared to the typical QSAR for polar narcosis in water-only systems probably due to the simultaneous exposure of the snail to LAS through the dissolved and the sediment associated fractions. The egestion rate of the surviving snails recovered after few days' exposure (1-d NOEC: 40-107 mg/kg, 9-d NOEC: 65-190 mg/kg) which suggests that the organisms were able to acclimate to LAS during the exposure.

  17. Adsorption/desorption of linear alkylbenzenesulfonate (LAS) and azoproteins by/from activated sludge flocs.

    PubMed

    Conrad, A; Cadoret, A; Corteel, P; Leroy, P; Block, J-C

    2006-01-01

    Our study investigated the adsorption/desorption by/from activated sludge flocs, dispersed in river water or in diluted wastewater, of organic compounds (C(11)-LAS, azoalbumin and azocasein) at concentrations relevant to environmental conditions. Activated sludge flocs, used as a model of biological aggregates, are characterized by a very heterogeneous matrix able to sorb the three organic compounds tested at 4 degrees C. The adsorbed amount of C(11)-LAS by activated sludge flocs was higher than that of azocasein or azoalbumin, as shown by the Freundlich parameters (K(ads)=8.6+/-1.7, 1.6+/-0.3 and 0.3+/-0.1 micromol(1-1/n)g(-1)l(1/n) for C(11)-LAS, azocasein and azoalbumin, respectively; n=3 sludges). C(11)-LAS sorption from activated sludge appeared to be partially reversible in river water, while a marked hysteresis phenomenon was observed for azocasein and azoalbumin, implying a low degree of reversibility in their exchange between activated sludge and river water. It has also been displayed that the conductivity variation of bulk water (comprised between 214 and 838 microS cm(-1)) exerted no dramatic effect on the C(11)-LAS desorption from activated sludge flocs, while a little effect of it on azocasein desorption was observed. Thus, biological aggregates as activated sludge flocs can serve as an intermediate carrier for C(11)-LAS, while it represents a sink for proteins.

  18. A novel small molecule, LAS-0811, inhibits alcohol-induced apoptosis in VL-17A cells.

    PubMed

    Kim, Tae-Hun; Venugopal, Senthil K; Zhu, Ming; Wang, Si-Si; Lau, Derick; Lam, Kit S; Clemens, Dahn L; Zern, Mark A

    2009-02-20

    One of the pathways by which alcohol induces hepatocyte apoptosis is via oxidative stress. We screened several chemically-synthesized small molecules and found LAS-0811, which inhibits oxidative stress. In this study, we elucidated its role in inhibiting alcohol-induced apoptosis in hepatocyte-like VL-17A cells. VL-17A cells were pre-incubated with LAS-0811, followed by ethanol incubation. Ethanol-induced reactive oxygen species and apoptosis were significantly inhibited in LAS-0811 pre-treated cells. VL-17A cells were transfected with a reporter (ARE/TK-GFP) plasmid containing green fluorescent protein (GFP) as a reporter gene and the anti-oxidant response element as the promoter. LAS-0811 pre-treatment significantly induced the GFP expression compared to the cells treated with ethanol alone. LAS-0811 induced the activation of nrf2 and enhanced the expression and activity of glutathione peroxidase, one of the downstream targets of nrf2. The results indicate that LAS-0811 protects VL-17A cells against ethanol-induced oxidative stress and apoptosis at least in part via nrf2 activation.

  19. Monitoring Changes in Channel Morphology in Las Vegas Wash with Global Fiducials Program Imagery

    NASA Astrophysics Data System (ADS)

    Wheeler, D. J.

    2012-12-01

    To borrow from a popular adage, "What happens in Las Vegas [Wash], stays in Las Vegas [Wash]"—but only with a lot of help. This past decade has seen a concerted effort to curb erosion and sediment transport along the 12 mile long channel between East Las Vegas and Lake Mead. Las Vegas Wash is prototypical of an urban river in an arid environment that is being impacted by increasing urban development and impervious surface runoff within its drainage area. Rapid urbanization since the 1970s has increased the flow of water into Las Vegas Wash, causing severe channel destabilization. Within two decades millions of cubic yards of rocks and sediment were scoured out of the wash and transported downstream to Lake Mead. The wetlands that once covered over 2,000 acres within Las Vegas Wash dwindled to 200 acres in the 1990s as the channel became as much as 40 feet deeper and 300 feet wider at some points. In 1999 the Las Vegas Wash Coordination Committee (LVWCC) initiated a 20-year plan to construct erosion control structures (weirs) for channel stabilization and rock riprap for stream bank protection. The hope is to design structures that will slow down the water flow, trap sediments, and to eventually restore much of the wetland environment. Using high-resolution satellite imagery from the Global Fiducials Program Library housed at the U. S. Geological Survey, this transition is being tracked from 1999 to the present. From November 1999 to July 2008 new residential and commercial development has claimed an additional 12 square kilometers (3000 acres) of land in Henderson, NV, along the south side of Las Vegas Wash. Even with the increased volume of surface and groundwater runoff entering the wash, current sediment yields are much lower than the 1999 totals. The imagery documents the construction of 14 of the 22 LVWCC planned weirs by the year 2011. It also shows many miles of stream bank stabilization by riprap, planting of riparian vegetation and placing of

  20. Environmentally Endemic Pseudomonas aeruginosa Strains with Mutations in lasR Are Associated with Increased Disease Severity in Corneal Ulcers

    PubMed Central

    Hammond, John H.; Hebert, Wesley P.; Naimie, Amanda; Ray, Kathryn; Van Gelder, Rachel D.; DiGiandomenico, Antonio; Lalitha, Prajna; Srinivasan, Muthiah; Acharya, Nisha R.; Lietman, Thomas; Hogan, Deborah A.

    2016-01-01

    ABSTRACT The Steroids for Corneal Ulcers Trial (SCUT) was a multicenter, international study of bacterial keratitis in which 101 Pseudomonas aeruginosa infections were treated. Twenty-two of 101 P. aeruginosa isolates collected had a colony morphology characteristic of a loss-of-function mutation in lasR, the gene encoding a quorum-sensing master regulator. Ulcers caused by these 22 strains were associated with larger areas of corneal opacification, worse vision, and a lower rate of vision recovery in response to treatment than ulcers caused by the other isolates. The lasR sequences from these isolates each contained one of three nonsynonymous substitutions, and these strains were deficient in production of LasR-regulated protease and rhamnolipids. Replacement of lasR with either of the two most common lasR alleles from the SCUT isolates was sufficient to decrease protease and rhamnolipid production in PA14. Loss of LasR function is associated with increased production of CupA fimbriae, and the LasR-defective isolates exhibited higher production of CupA fimbriae than LasR-intact isolates. Strains with the same lasR mutation were of the same multilocus sequence type, suggesting that LasR-deficient, environmental P. aeruginosa strains were endemic to the area, and infections caused by these strains were associated with worse patient outcomes in the SCUT study. (This study has been registered at ClinicalTrials.gov under registration no. NCT00324168.) IMPORTANCE The LasR transcription factor is an important regulator of quorum sensing in P. aeruginosa and positively controls multiple virulence-associated pathways. The emergence of strains with lasR loss-of-function alleles in chronic disease is well described and is thought to represent a specific adaptation to the host environment. However, the prevalence and virulence of these strains in acute infections remain unclear. This report describes observations revealing that lasR mutants were common among isolates from

  1. LasR Variant Cystic Fibrosis Isolates Reveal an Adaptable Quorum-Sensing Hierarchy in Pseudomonas aeruginosa.

    PubMed

    Feltner, John B; Wolter, Daniel J; Pope, Christopher E; Groleau, Marie-Christine; Smalley, Nicole E; Greenberg, E Peter; Mayer-Hamblett, Nicole; Burns, Jane; Déziel, Eric; Hoffman, Lucas R; Dandekar, Ajai A

    2016-10-04

    Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P. aeruginosa CF isolates, little is known about their consequences for QS. We sequenced lasR from 2,583 P. aeruginosa CF isolates. The lasR sequences of 580 isolates (22%) coded for polypeptides that differed from the conserved LasR polypeptides of well-studied laboratory strains. This collection included 173 unique lasR coding variants, 116 of which were either missense or nonsense mutations. We studied 31 of these variants. About one-sixth of the variant LasR proteins were functional, including 3 with nonsense mutations, and in some LasR-null isolates, genes that are LasR dependent in laboratory strains were nonetheless expressed. Furthermore, about half of the LasR-null isolates retained RhlR activity. Therefore, in some CF isolates the QS hierarchy is altered such that RhlR quorum sensing is independent of LasR regulation. Our analysis challenges the view that QS-silent P. aeruginosa is selected during the course of a chronic CF lung infection. Rather, some lasR sequence variants retain functionality, and many employ an alternate QS strategy involving RhlR.

  2. LasR Variant Cystic Fibrosis Isolates Reveal an Adaptable Quorum-Sensing Hierarchy in Pseudomonas aeruginosa

    PubMed Central

    Feltner, John B.; Wolter, Daniel J.; Pope, Christopher E.; Groleau, Marie-Christine; Smalley, Nicole E.; Greenberg, E. Peter; Mayer-Hamblett, Nicole; Burns, Jane; Hoffman, Lucas R.

    2016-01-01

    ABSTRACT Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P. aeruginosa CF isolates, little is known about their consequences for QS. We sequenced lasR from 2,583 P. aeruginosa CF isolates. The lasR sequences of 580 isolates (22%) coded for polypeptides that differed from the conserved LasR polypeptides of well-studied laboratory strains. This collection included 173 unique lasR coding variants, 116 of which were either missense or nonsense mutations. We studied 31 of these variants. About one-sixth of the variant LasR proteins were functional, including 3 with nonsense mutations, and in some LasR-null isolates, genes that are LasR dependent in laboratory strains were nonetheless expressed. Furthermore, about half of the LasR-null isolates retained RhlR activity. Therefore, in some CF isolates the QS hierarchy is altered such that RhlR quorum sensing is independent of LasR regulation. Our analysis challenges the view that QS-silent P. aeruginosa is selected during the course of a chronic CF lung infection. Rather, some lasR sequence variants retain functionality, and many employ an alternate QS strategy involving RhlR. PMID:27703072

  3. El fenotipo de las mucinas en el esófago de Barrett

    PubMed Central

    Torrado, Julio; Piazuelo, María Blanca; Ruiz, Irune; Izarzugaza, María Isabel; Camargo, María Constanza; Delgado, Alberto; Abdirad, Afshin; Correa, Pelayo

    2011-01-01

    Antecedentes El esófago de Barrett es una reconocida lesión precursora de adenocarcinoma esofágico. Aunque generalmente asociada al reflujo gastroesofágico, los mecanismos patogénicos de la enfermedad no son bien conocidos. El objetivo del presente estudio es explorar la historia natural e identificar marcadores de progreso del proceso precanceroso. Material y métodos Se utilizaron cortes histológicos de 67 especímenes de esófago correspondientes a 14 pacientes con esófago de Barrett, a los que se siguió entre 1 – 9 años. Se clasificaron las lesiones en: esófago de Barrett sin displasia, indefinido para displasia o con displasia. Se evaluó la expresión de diferentes mucinas en las células caliciformes y en las columnares usando técnicas de histoquímica e inmunohistoquímica. Resultados En todos los casos se comprobó la presencia de metaplasia intestinal incompleta. Las células columnares dentro del epitelio metaplásico contenían mucinas neutras. A mayor severidad de la lesión se encontró significativamente menor expresión de sialomucinas en las células columnares (p de tendencia igual a 0,03). En sujetos con lesiones indefinidas para displasia se observó un mayor contenido de sulfomucinas en las células caliciformes (p=0,034) y de MUC2 en las células columnares (p=0,029) que en sujetos con esófago de Barrett sin displasia. Se observó expresión de la mucina intestinal MUC2 y de la mucina gástrica MUC5AC en todas las muestras. MUC6, una mucina de las glándulas profundas gástricas, se presentó ocasionalmente. Conclusión La evaluación de los perfiles de mucinas en el esófago de Barrett sugiere una transición gradual del fenotipo del epitelio metaplásico a medida que la lesión avanza en el tiempo. PMID:21804831

  4. Cystic fibrosis-adapted Pseudomonas aeruginosa quorum sensing lasR mutants cause hyperinflammatory responses.

    PubMed

    LaFayette, Shantelle L; Houle, Daniel; Beaudoin, Trevor; Wojewodka, Gabriella; Radzioch, Danuta; Hoffman, Lucas R; Burns, Jane L; Dandekar, Ajai A; Smalley, Nicole E; Chandler, Josephine R; Zlosnik, James E; Speert, David P; Bernier, Joanie; Matouk, Elias; Brochiero, Emmanuelle; Rousseau, Simon; Nguyen, Dao

    2015-07-01

    Cystic fibrosis lung disease is characterized by chronic airway infections with the opportunistic pathogen Pseudomonas aeruginosa and severe neutrophilic pulmonary inflammation. P. aeruginosa undergoes extensive genetic adaptation to the cystic fibrosis (CF) lung environment, and adaptive mutations in the quorum sensing regulator gene lasR commonly arise. We sought to define how mutations in lasR alter host-pathogen relationships. We demonstrate that lasR mutants induce exaggerated host inflammatory responses in respiratory epithelial cells, with increased accumulation of proinflammatory cytokines and neutrophil recruitment due to the loss of bacterial protease- dependent cytokine degradation. In subacute pulmonary infections, lasR mutant-infected mice show greater neutrophilic inflammation and immunopathology compared with wild-type infections. Finally, we observed that CF patients infected with lasR mutants have increased plasma interleukin-8 (IL-8), a marker of inflammation. These findings suggest that bacterial adaptive changes may worsen pulmonary inflammation and directly contribute to the pathogenesis and progression of chronic lung disease in CF patients.

  5. Identification of methyl triclosan and halogenated analogues in male common carp (Cyprinus carpio) from Las Vegas Bay and semipermeable membrane devices from Las Vegas Wash, Nevada.

    PubMed

    Leiker, Thomas J; Abney, Sonja R; Goodbred, Steven L; Rosen, Michael R

    2009-03-01

    Methyl triclosan and four halogenated analogues have been identified in extracts of individual whole-body male carp (Cyprinus carpio) tissue that were collected from Las Vegas Bay, Nevada, and Semipermeable Membrane Devices (SPMD) that were deployed in Las Vegas Wash, Nevada. Methyl triclosan is believed to be the microbially methylated product of the antibacterial agent triclosan (2, 4, 4'-trichloro-4-hydroxydiphenyl ether, Chemical Abstract Service Registry Number 3380-34-5, Irgasan DP300). The presence of methyl triclosan and four halogenated analogues was confirmed in SPMD extracts by comparing low- and high-resolution mass spectral data and Kovats retention indices of methyl triclosan with commercially obtained triclosan that was derivatized to the methyl ether with ethereal diazomethane. The four halogenated analogues of methyl triclosan detected in both whole-body tissue and SPMD extracts were tentatively identified by high resolution mass spectrometry. Methyl triclosan was detected in all 29 male common carp from Las Vegas Bay with a mean concentration of 596 microg kg(-1) wet weight (ww) which is more than an order of magnitude higher than previously reported concentrations in the literature. The halogenated analogs were detected less frequently (21%-76%) and at much lower concentrations (<51 microg kg(-1) ww). None of these compounds were detected in common carp from a Lake Mead reference site in Overton Arm, Nevada.

  6. Identification of methyl triclosan and halogenated analogues in male common carp (Cyprinus carpio) from Las Vegas Bay and semipermeable membrane devices from Las Vegas Wash, Nevada

    USGS Publications Warehouse

    Leiker, T.J.; Abney, S.R.; Goodbred, S.L.; Rosen, Michael R.

    2009-01-01

    Methyl triclosan and four halogenated analogues have been identified in extracts of individual whole-body male carp (Cyprinus carpio) tissue that were collected from Las Vegas Bay, Nevada, and Semipermeable Membrane Devices (SPMD) that were deployed in Las Vegas Wash, Nevada. Methyl triclosan is believed to be the microbially methylated product of the antibacterial agent triclosan (2, 4, 4'-trichloro-4-hydroxydiphenyl ether, Chemical Abstract Service Registry Number 3380-34-5, Irgasan DP300). The presence of methyl triclosan and four halogenated analogues was confirmed in SPMD extracts by comparing low- and high-resolution mass spectral data and Kovats retention indices of methyl triclosan with commercially obtained triclosan that was derivatized to the methyl ether with ethereal diazomethane. The four halogenated analogues of methyl triclosan detected in both whole-body tissue and SPMD extracts were tentatively identified by high resolution mass spectrometry. Methyl triclosan was detected in all 29 male common carp from Las Vegas Bay with a mean concentration of 596????g kg- 1 wet weight (ww) which is more than an order of magnitude higher than previously reported concentrations in the literature. The halogenated analogs were detected less frequently (21%-76%) and at much lower concentrations (< 51????g kg- 1 ww). None of these compounds were detected in common carp from a Lake Mead reference site in Overton Arm, Nevada.

  7. Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) Aircraft Measurements of CO2

    NASA Technical Reports Server (NTRS)

    Christensen, Lance E.; Spiers, Gary D.; Menzies, Robert T.; Jacob, Joseph C.; Hyon, Jason

    2011-01-01

    The Jet Propulsion Laboratory Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) utilizes Integrated Path Differential Absorption (IPDA) at 2.05 microns to obtain CO2 column mixing ratios weighted heavily in the boundary layer. CO2LAS employs a coherent detection receiver and continuous-wave Th:Ho:YLF laser transmitters with output powers around 100 milliwatts. An offset frequency-locking scheme coupled to an absolute frequency reference enables the frequencies of the online and offline lasers to be held to within 200 kHz of desired values. We describe results from 2009 field campaigns when CO2LAS flew on the Twin Otter. We also describe spectroscopic studies aimed at uncovering potential biases in lidar CO2 retrievals at 2.05 microns.

  8. Sobre las soluciones acotadas del problema instantáneo de dos cuerpos

    NASA Astrophysics Data System (ADS)

    Altavista, C.

    La demostración se basa en el hecho de que las integrales del problema de los N-cuerpos admiten componentes en el campo complejo según las raíces n-ésimas de la unidad. Definida la matriz unitaria correspondiente, la fórmula de Cayley permite transformar la matriz unitaria en una matriz hermitiana. Utilizando como parámetros los cosenos direccionales de un sistema de coordenadas orbitales referidos a un sistema de referencia fijo, puede construirse, utilizando el operador hermitiano antes definido, una forma cuadrática cuyas raíces mínima y máxima definen las cotas respectivas de los movimientos de los mencionados cosenos direccionales.

  9. Estudio de la transparencia de las nubes de Magallanes a partir de la observación espectroscópica de galaxias ubicadas en dirección a las mismas

    NASA Astrophysics Data System (ADS)

    Dutra, C.; Bica, E.; Clariá, J. J.; Piatti, A. E.:

    Se presentan los primeros resultados obtenidos a partir de observaciones espectroscópicas de galaxias ubicadas en dirección a las Nubes de Magallanes. Los espectros fueron obtenidos con el telescopio de 2.15 m del CASLEO y cubren el rango 3500-7000 Å. El material observacional recolectado permite examinar poblaciones estelares y determinar el enrojecimiento interestelar que afecta a cada una de las galaxias. La distribución angular de la muestra de galaxias observadas permite efectuar el mapeamiento del enrojecimiento que afecta las distintas regiones de las Nubes de Magallanes.

  10. El aprendizaje significativo en las ciencias al participar en proyectos de investigacion cientifica

    NASA Astrophysics Data System (ADS)

    Mora Polanco, Miguelena

    La ciencia es el eje fundamental a traves del cual se desarrollan las habilidades necesarias para el pensar cientifico que va a la busqueda del conocimiento cientifico. La intencion de este estudio fue indagar en el tema de investigacion cientifica desde el punto de vista de los participantes en los siguientes aspectos relacionados con la experiencia de investigacion cientifica: a) conceptos, b) proceso, c) destrezas y d) disposicion. Tambien se analizaron: a) las perspectivas del metodo cientifico, b) la estrategia de ensenanza, c) la cultura cientifica y d) la exposicion del proyecto investigativo en la Feria Cientifica; como parte del aprendizaje significativo de la ciencias de los participantes. Esta investigacion cualitativa propuso como diseno el estudio de caso. Los aspectos relacionados a la experiencia de participar en proyecto de investigacion cientifica son el fenomeno o caso bajo estudio. En el estudio participaron cinco (5) estudiantes egresados de escuela publica o privada que cursaban hasta el tercer ano de estudios universitarios, conducentes a un bachillerato en educacion secundaria en ciencias o en ciencias naturales. Las tecnicas utilizadas para recopilar los datos fueron: analisis de documentos del DEPR, revision de artefactos y entrevistas profundas. Para el analisis de los datos de las entrevistas se utilizo el modelo de Wolcott (1994). Del analisis de documentos del DEPR se identificaron areas a mejorar en las guias de las cartas circulares con relacion a la investigacion escolar y la feria cientifica. El analisis de los artefactos proveyo evidencia de como los internados, simposios e investigaciones fomentan el que los estudiantes se superen en el aspecto cognitivo, se conviertan en creadores del conocimiento, al hacer suyo los conceptos para poder explicarlos al publico. De las entrevistas los participantes manifestaron que la experiencia de investigacion fue una de aprendizaje significativo que los marco para toda la vida y les expandio su

  11. A reinterpretation of the Pleistocene human and faunal association at Las Buitreras Cave, Santa Cruz, Argentina

    NASA Astrophysics Data System (ADS)

    Borrero, Luis A.; Martin, Fabiana M.

    2008-12-01

    The faunal assemblage recovered from Layers VIII-VII at Las Buitreras Cave has been considered as associated with human artifacts. On that basis, the previous analysis had concluded that human hunters had exploited ground sloths at the end of the Pleistocene. A reanalysis of the bones as well as the rest of the evidence suggests that there is no basis for that conclusion. On the contrary, it is suggested here that the lower layers at Las Buitreras are the result of the use of the cave as a den by ground sloths.

  12. Las fulguraciones como manifestación de reconexión en el campo magnético solar

    NASA Astrophysics Data System (ADS)

    Bagalá, L. G.; Mandrini, M. C.; Rovira, M. G.; Démoulin, P.

    Las fulguraciones solares son fenómenos transitorios de liberación de energía que se desarrollan en las estructuras magnéticas de las regiones activas del Sol. Las fulguraciones pueden llegar a liberar hasta 1032 erg en 100 seg. en todo el rango electromagnético, y acelerar partículas. En este trabajo mostramos que la ubicación de los abrillantamientos en Hα de diversas fulguraciones está relacionado con las propiedades de las conexiones de las líneas del campo magnético de la región, como se espera por las teorías de reconexión en 3D recientemente desarrolladas (Démoulin et al, 1996a). El campo magnético coronal se extrapola del campo fotosférico observado suponiendo una configuración libre de fuerzas lineal. Por medio de un algoritmo se determinan las regiones donde existe un cambio drástico en la conectividad de las líneas de campo (límites ``cuasi-discontinuos'', o cuasi-separatrices CS). Las CS son bandas abiertas que identifican zonas donde el campo magnético se reconectará con más probabilidad y, siempre que las mismas sean lo suficientemente finas, se producirá allíla liberación de energía proveniente del campo magnético. Hemos encontrado que en todas las regiones fulgurantes estudiadas (Démoulin et al, 1996b) existen CS en los mismos lugares donde se observaron los abrillantamientos en Hα. Allídonde coinciden los abrillantamientos con las CS, éstas tienen un espesor menor que 1 Mm. Las líneas de campo coronales extrapoladas de nuestro modelo tienen sus orígenes fotosféricos a ambos lados de las CS, como se espera dados los recientes estudios de reconexión magnética en 3D. Estos resultados ponen a prueba los modelos presentes sobre fulguraciones solares.

  13. Omega-oxygenation of the alkyl sidechain of linear alkylbenzenesulfonate (LAS) surfactant in Parvibaculum lavamentivorans(T).

    PubMed

    Schleheck, David; Cook, Alasdair M

    2005-09-01

    Parvibaculum lavamentivorans (T) DS-1, an aerobic, heterotrophic bacterium, requires a biofilm on a solid surface (e.g. glass particles) when utilizing commercial linear alkylbenzenesulfonate surfactant (LAS; 20 congeners) for growth. Catabolism involves the undefined 'omega-oxygenation' and beta-oxidation of the LAS side chain, and the organism excretes sulfophenyl carboxylates (SPC) quantitatively. A 3.5-l fermenter was developed which allowed gram-quantities of LAS-grown cells to be grown and harvested from medium with glass particles as the solid support. The catabolism of LAS was dominant: in diauxie experiments with acetate as second carbon source, LAS was utilized first. The biofilm-encoated LAS-grown cells were unsuitable for metabolic work in vitro because cell suspensions clumped and were not disrupted effectively, but the degradative enzymes were found to be expressed constitutively in acetate-grown cells, which formed no biofilm. LAS-dependent oxygen uptake was measured in acetate-grown cells at about 0.6 mkat (kg protein)(-1), but not in extracts of cells. Whole cells converted LAS to SPC in the presence of molecular oxygen only, and the reaction could be saturably inhibited by metyrapone, which acts on e.g. cytochromes P450 (CYP). However, despite the presence of CYP153-like sequences in the genome of strain DS-1(T), the difference spectra did not support the presence of a CYP in crude extracts, and the nature of the LAS-oxygenase remains unclear.

  14. Cloning and characterization of the Pseudomonas aeruginosa lasR gene, a transcriptional activator of elastase expression.

    PubMed Central

    Gambello, M J; Iglewski, B H

    1991-01-01

    We report the discovery of the lasR gene, which positively regulates elastase expression in Pseudomonas aeruginosa PAO1. The lasR gene was cloned by its ability to restore a positive elastase phenotype in strain PA103, a strain which possesses the elastase structural gene (lasB) but fails to synthesize the enzyme. Nucleotide sequence analysis revealed an open reading frame of 716 nucleotides encoding a protein of approximately 27 kDa. A labeled LasR protein of 27 kDa was detected in Escherichia coli by using a T7 RNA polymerase expression system. A chromosomal deletion mutant of the lasR gene was constructed in PAO1 by gene replacement. This mutant (PAO-R1) is devoid of elastolytic activity and elastase antigen. The deduced amino acid sequence of LasR is 27% homologous to the positive activator LuxR of Vibrio fischeri and the suspected activator 28K-UvrC of E. coli. Northern (RNA) analysis of total cellular RNA from PAO1, PAO-R1, and PAO-R1 containing the lasR gene on a multicopy plasmid (pMG1.7) revealed that a functional lasR gene is required for transcription of the elastase structural gene (lasB). Images PMID:1902216

  15. Hydrologic impacts of climate change and urbanization in Las Vegas Wash Watershed, Nevada

    EPA Science Inventory

    In this study, a cell-based model for the Las Vegas Wash (LVW) Watershed in Clark County, Nevada, was developed by combining the traditional hydrologic modeling methods (Thornthwaite’s water balance model and the Soil Conservation Survey’s Curve Number method) with the pixel-base...

  16. Changes in the morphometry of Las Vegas Wash and the impact on water quality

    USGS Publications Warehouse

    Roline, Richard A.; Sartoris, James J.

    1988-01-01

    Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mean. Over 80 percent of the normal discharge of approximately 3.4 m3/s (120 ft3/s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly reduced the wetland area within Las Vegas Wash. The reduction in wetland area shortened water travel time in the wash and affected water quality. The primary impacts on the water entering Lake Mead have been an increase in temperature, a decrease in dissolved oxygen concentration, and an increase in ammonia levels. Other physical-chemical parameters and changes in nutrient transformations are also discussed.

  17. The Development of Child Subjectivity in "La lengua de las mariposas"

    ERIC Educational Resources Information Center

    Ryan, Lorraine

    2012-01-01

    Jose Luis Cuerda's film "La lengua de las mariposas" is set in rural Galicia in the immediate lead-up to the outbreak of the Spanish Civil War. It portrays the tender relationship between a Republican schoolteacher, Don Gregorio, and a boy named Moncho. Upon the Nationalist capture of the town, the young Moncho hurls stones at his…

  18. Twelve Years of Sociocultural Action in the Las Villas Area. Chapter 2.

    ERIC Educational Resources Information Center

    Gonzalez, Quintin Garcia

    This chapter reports on the activities of the Rural Continuing Education Centre (CREPA), a nongovernmental organization run by volunteers from small agricultural villages in the Las Villas area of Salamanca, Spain. The organization was founded in 1983 with the goal of improving living conditions and community life for villagers through social…

  19. 75 FR 38778 - Expansion of Foreign-Trade Zone 89 Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-06

    ... [Federal Register Volume 75, Number 128 (Tuesday, July 6, 2010)] [Notices] [Page 38778] [FR Doc No: 2010-16356] DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Order No. 1688] Expansion of Foreign-Trade Zone 89 Las Vegas, NV Pursuant to its authority under the Foreign-Trade Zones Act of June 18,...

  20. PERCHLORATE UPTAKE BY SALT CEDAR (TAMARIX RAMOSISSIMA) IN THE LAS VEGAS WASH RIPARIAN ECOSYSTEM

    EPA Science Inventory

    Perchlorate ion (CIO4-) has been identified in samples of dormant salt cedar (Tamarix ramosissima) growing in the Las vegas Wash. Perchlorate is an oxidenat, but its reduction is kineticaly hindered. CXoncern over thyrpoid effects caused the Environmental Protection Agency (EPA...

  1. 77 FR 55225 - Notice of Public Meeting, Las Cruces District Resource Advisory Council Meeting, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-07

    ... (FIRS) at 1-800-877-8229 to contact the above individual during normal business hours. The FIRS is... receive a reply during normal business hours. SUPPLEMENTARY INFORMATION: The 10-member RAC advises the.... Bill Childress, District Manager, Las Cruces. BILLING CODE 4310-VC-P...

  2. Perceptions toward the Value of Higher Education for Hotel Professionals in Las Vegas: A Case Study

    ERIC Educational Resources Information Center

    Deel, Gary Lee

    2015-01-01

    This study concerns a qualitative investigation of the views toward higher education and its importance to hospitality career success among hotel professionals in the Las Vegas, Nevada area. Existing literature supported the premise that education may be important to professional career success in several different ways, and that values concerning…

  3. Orion Launch Abort System (LAS) Propulsion on Pad Abort 1 (PA-1)

    NASA Technical Reports Server (NTRS)

    Jones, Daniel S.

    2015-01-01

    This presentation provides a concise overview of the highly successful Orion Pad Abort 1 (PA-1) flight test, and the three rocket motors that contributed to this success. The primary purpose of the Orion PA-1 flight was to help certify the Orion Launch Abort System (LAS), which can be utilized in the unlikely event of an emergency on the launchpad or during mission vehicle ascent. The PA-1 test was the first fully integrated flight test of the Orion LAS, one of the primary systems within the Orion Multi-Purpose Crew Vehicle (MPCV). The Orion MPCV is part of the architecture within the Space Launch System (SLS), which is being designed to transport astronauts beyond low-Earth orbit for future exploration missions. Had the Orion PA-1 flight abort occurred during launch preparations for a real human spaceflight mission, the PA-1 LAS would have saved the lives of the crew. The PA-1 flight test was largely successful due to the three solid rocket motors of the LAS: the Attitude Control Motor (ACM); the Jettison Motor (JM); and the Abort Motor (AM). All three rocket motors successfully performed their required functions during the Orion PA-1 flight test, flown on May 6, 2010 at the White Sands Missile Range in New Mexico, culminating in a successful demonstration of an abort capability from the launchpad.

  4. Hydrogeochemical and stream sediment reconnaissance basic data for Las Cruces quadrangle, New Mexico

    SciTech Connect

    Not Available

    1981-08-31

    Field and laboratory data are presented for 501 water samples and 1817 sediment samples from the Las Cruces Quadrangle, New Mexico. The samples were collected and uranium analysis performed by Los Alamos National Laboratory; multielement analysis and data reporting were performed by the Uranium Resource Evaluation Project at Oak Ridge, Tennessee.

  5. Episodic Impacts from California Wildfires Identified in Las Vegas Near-Road Air Quality Monitoring

    EPA Science Inventory

    Air pollutant concentrations near major highways are usually attributed to a combination of nearby traffic emissions and regional background, and generally presumed to be additive in nature. During a recent year-long near-road monitoring study conducted in Las Vegas, NV, a substa...

  6. 77 FR 65332 - Proposed Modification of Class B Airspace; Las Vegas, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... the containment of large turbine-powered aircraft within Class B airspace, reduce air traffic... to ensure that turbine-powered aircraft operations were fully contained within the TCA (47 FR 30052... LAS Class B does not fully contain turbine-powered aircraft as required by FAA directives....

  7. Geophysical constraints on the location and geometry of the Las Vegas Shear Zone, Nevada

    USGS Publications Warehouse

    Langenheim, V.E.; Grow, J.A.; Jachens, R.C.; Dixon, G.L.; Miller, J.J.

    2001-01-01

    We model the basin configuration beneath Las Vegas Valley, Nevada, on the basis of gravity, drillhole, and seismic reflection data. We locate and characterize the various strands of the Las Vegas Valley Shear Zone (LVVSZ) by variations in basin thickness beneath the valley. The pre-Tertiary bedrock surface is complex, with subbasins buried beneath the flat alluvial surface of the valley. We suggest that these basins are formed from transtensional strain. Subbasins elongated N70??W and N50??W are interpreted as strike-slip basins. The deepest subbasin is 5 km west of Frenchman Mountain and strikes N40??E. This basin probably formed by combined movement on nonparallel strands of the LVVZ and an earlier episode of normal faulting. The basin thickness map constrains the minimum depth of the inferred detachment fault beneath Las Vegas Valley to at least 4 km. Seismic reflection data do not image a detachment fault in the upper 10 km beneath Las Vegas Valley. Our results also illustrate the utility of gravity in determining basinal structures and providing a three-dimensional perspective in areas with limited seismic reflection control.

  8. Builders Challenge High Performance Builder Spotlight - Masco Environments for Living, Las Vegas, Nevada

    SciTech Connect

    2009-01-01

    Building America Builders Challenge fact sheet on Masco’s Environments for Living Certified Green demo home at the 2009 International Builders Show in Las Vegas. The home has a Home Energy Rating System (HERS) index score of 44, a right-sized air conditi

  9. Builders Challenge High Performance Builder Spotlight - NextGen Home, Las Vegas, Nevada

    SciTech Connect

    2009-01-01

    Building America Builders Challenge fact sheet on the NextGen demo home built in Las Vegas. The home has a Home Energy Rating System (HERS) index score of 44 with R-40 spray foam attic insulation, R-40 insulated concrete walls, and a 4kW DC solar laminate

  10. Isolation of the Autoinducer-Quenching Strain that Inhibits LasR in Pseudomonas aeruginosa

    PubMed Central

    Weng, Lixing; Zhang, Yuqian; Yang, Yuxiang; Wang, Lianhui

    2014-01-01

    Quorum sensing (QS) has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identified. A confirmatory bioassay was carried out after concentrating the putative positive culture supernatant, and 22 strains were confirmed to have anti-LasR activity. Finally, we determined the strain JM2, which could completely inhibit biofilm formation of Pseudomonas aeruginosa PAO1, belonged to the genus Pseudomonas by analysis of 16S rDNA. Partially purified inhibitor factor(s) F5 derived from culture supernatants specifically inhibited LasR-controlled elastase and protease in wild type P. aeruginosa PAO1 by 68% and 73%, respectively, without significantly affecting growth; the rhl-controlled pyocyanin and rhamnolipids were inhibited by 54% and 52% in the presence of 100 μg/mL of F5. The swarming motility and biofilm of PAO1 were also inhibited by F5. Real time RT-PCR on samples from 100 μg/mL F5-treated P. aeruginosa showed downregulation of autoinducer synthase (LasRI and rhlI) and cognate receptor (lasR and rhlR) genes by 50%, 28%, 48%, and 29%, respectively. These results provide compelling evidence that the F5 inhibitor(s) interferes with the las system and significantly inhibits biofilm formation. PMID:24736783

  11. 75 FR 60496 - Kern Valley Railroad Company-Termination of Trackage Rights-in Las Animas County, CO

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Surface Transportation Board Kern Valley Railroad Company--Termination of Trackage Rights--in Las Animas... milepost 0.0 and milepost 2.0 in Jansen, Las Animas County, Colo. (the line). The line traverses...

  12. Bioconcentration and toxicity of dodecylbenzene sulfonate (C12LAS) to aquatic organisms exposed in experimental streams.

    PubMed

    Versteeg, D J; Rawlings, J M

    2003-02-01

    Fish, mollusks, and crustaceans were caged in the tail pool of streams during a C(12)LAS (dodecyl benzene sulfonate) model ecosystem experimental program. Bioconcentration of total C(12)LAS and individual isomers and acute and chronic toxicity were investigated during this study. Toxicity endpoints were based on water and tissue (i.e., body burden) concentrations at which adverse effects were observed. At 32 days, total C(12)LAS bioconcentration factors (BCFs) for the fathead minnow and three invertebrate species ranged from 9 to 116. In general, bioconcentration was affected by isomer position, exposure concentration, and species. BCF values tended to decrease as isomer position moved from external (e.g., 2-phenyl) to internal (e.g., 5,6-phenyl). BCFs also decreased as exposure concentration increased. Mean acute 4-d LC(50) values ranged from 1.5 to >3.0 mg/L for the six species tested. Lethal body burdens associated with 50% mortality (LBB(50)) varied from 0.21 to 0.60 mmole/kg (wet weight). During the 32-day chronic exposures, the EC(20) values were 0.27 (0.204-0.352), 0.95 (0.597-1.29), and approximately 1.0 mg/L for Corbicula (length), Hyalella (survival), and fathead minnow (survival), respectively. At these EC(20) values, C(12)LAS body burdens were 0.035, 0.23, and 0.19 mmoles/kg wet weight in Corbicula, Hyalella, and fathead minnow, respectively. Fish exposed to wastewater treatment plant effluent had total C(12)LAS tissue concentrations ranging from 0.0005 to 0.0039 mmoles/kg wet weight. These concentrations are approximately 45-360 times below the tissue concentration associated with subtle effects in the model ecosystem stream exposures. Total C(12)LAS body burdens in feral and caged Corbicula exposed to WWTP effluents were approximately 0.0013 mmoles/kg; approximately 25-fold below concentrations associated with effects in stream exposures.

  13. Targeting oxidative stress attenuates trinitrobenzene sulphonic acid induced inflammatory bowel disease like symptoms in rats: Role of quercetin

    PubMed Central

    Dodda, Dilip; Chhajed, Ruchi; Mishra, Jitendriya; Padhy, Monalisa

    2014-01-01

    Objective: This study was aimed to investigate the beneficial effects of quercetin (QCT) against trinitrobenzene sulfonic acid (TNBS) induced clinical, morphological, and biochemical alterations in rats. Materials and Methods: Colitis in rats was induced by administration of TNBS (25 mg dissolved in 0.25 ml of 30% ethanol) 8 cm into the rectum of the rat using a catheter. The animals were divided into six experimental groups (n = 6); naive (saline only without TNBS administration), control (saline + TNBS), standard (sulfasalazine 25 mg/kg + TNBS), QCT (25) (QCT 25 mg/kg + TNBS), QCT (50) (QCT 50 mg/kg + TNBS), QCT (100) (QCT 100 mg/kg + TNBS). Sulfasalazine (25 mg/kg) and QCT (25, 50 and 100 mg/kg) were administered per oral for 11 days and the colonic damage was evaluated in terms of macroscopical (body weight, stool consistency, rectal bleeding, and ulcer index) and biochemical parameters (myeloperoxidase activity, lipid peroxidation, nitrite, and glutathione). Results: Treatment with QCT (50, 100 mg/kg) for 10 days following TNBS administration significantly attenuated the clinical, morphological, and biochemical alterations induced by TNBS, whereas it was found to be not effective at its lower dose (25 mg/kg) throughout the experimental protocol. Conclusion: QCT attenuates the clinical, morphological and biochemical alterations induced by TNBS possibly via its antioxidant mechanism. PMID:24987175

  14. Perfluorinated carboxylic and sulphonic acids in surface water media from the regions of Tibetan Plateau: Indirect evidence on photochemical degradation?

    PubMed

    Yamazaki, Eriko; Falandysz, Jerzy; Taniyasu, Sachi; Hui, Ge; Jurkiewicz, Gabriela; Yamashita, Nobuyoshi; Yang, Yong-Liang; Lam, Paul K S

    2016-01-01

    Perfluorinated surfactants and repellents are synthetic substances that have found numerous industrial and customer applications. Due to their persistence, at least two groups of these substances-perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs)-are diffused widely in the environment. It is hypothesized that the Tibetan Plateau, is one of few unique places on the Earth, due to its topography, specifically the vast space and high elevation above sea level, geographic location, climate, high solar radiation, lack of industry, little urbanization and general lack of significant direct sources of pollution. There it is believed possible to gain an insight into atmospheric fate (possible photochemical degradation of higher molecular mass and formation of lower molecular mass PFCAs and PFSAs) of PFASs under un-disturbed environmental conditions. Ultratrace analytical method for PFCAs and PFSAs and use of transportation and field blanks, laboratory blanks and isotopically labelled surrogates for recovery control has allowed the determination of nine perfluorinated carboxylic acids and six perfluorinated sulfonic acids at ultra-trace levels in water based samples from the alpine dimension regions of the Tibetan Plateau, the eastern slope of Minya Konka peak at the eastern edge of the Tibetan Plateau, and also from the city of Chengdu from the lowland of the Sichuan Province in China. The specific compositional pattern of PFCAs and PFSAs and low levels of pollution with those compounds were observed in the central region of the Tibetan Plateau and in the region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau. The fingerprint of the compositional pattern of PFCAs and PFSAs in water samples in the central region of the Tibetan Plateau and in the alpine region adjacent to the peaks of Minya Konka in the Eastern Tibetan Plateau may be explained by the result of photochemical degradation with dealkylation of longer chain compounds and formation of shorter chain compounds, which are more resistant to photochemical degradation.

  15. The effect of specific rhlA-las-box mutations on DNA binding and gene activation by Pseudomonas aeruginosa quorum-sensing transcriptional regulators RhlR and LasR.

    PubMed

    González-Valdez, Abigail; Servín-González, Luis; Juárez, Katy; Hernandez-Aligio, Alberto; Soberón-Chávez, Gloria

    2014-07-01

    Pseudomonas aeruginosa is a free-living bacterium and an important opportunistic pathogen. The genes coding for virulence-associated traits are regulated at the level of transcription by the quorum-sensing response. In this response, the regulator LasR coupled with the autoinducer 3-oxo-dodecanoyl homoserine lactone (3O-C12-HSL) activates transcription of genes for several virulence factors. LasR/3O-C12-HSL also activates transcription of rhlR, the gene coding for the transcriptional regulator RhlR, and of rhlI that encodes the synthase that produces the autoinducer butanoyl-homoserine lactone (C4-HSL) that interacts with RhlR. Genes activated by RhlR/C4-HSL include those involved in rhamnolipids production (like the rhlAB operon) and lecA, coding for PA-I lectin. The molecular basis of LasR/3O-C12-HSL- and RhlR/C4-HSLDNA-binding specificity (at the so-called las-boxes) has not been clearly determined, and the aim of this work was to contribute to its understanding. Therefore, we analyzed the interaction of LasR and RhlR to variants of the rhlA-las-box that were constructed based on the comparison of this las-box to the las-box of lecA. We conclude that LasR and RhlR DNA-binding specificity is a complex multifactorial phenomenon in which both positive and negative effects are involved and that binding of these proteins does not necessarily result in gene activation.

  16. Reinterpretation of the stratigraphy and structure of the Rancho Las Norias area, central Sonora, Mexico

    USGS Publications Warehouse

    Page, W.R.; Harris, A.G.; Poole, F.G.; Repetski, J.E.

    2003-01-01

    New geologic mapping and fossil data in the vicinity of Rancho Las Norias, 30 km east of Hermosillo, Sonora, Mexico, show that rocks previously mapped as Precambrian instead are Paleozoic. Previous geologic maps of the Rancho Las Norias area show northeast-directed, southwest-dipping reverse or thrust faults deforming both Precambrian and Paleozoic rocks. The revised stratigraphy requires reinterpretation of some of these faults as high-angle normal or oblique-slip faults and the elimination of other faults. We agree with earlier geologic map interpretations that compressional structures have affected the Paleozoic rocks in the area, but our mapping suggests that the direction of compression is from southeast to northwest. Published by Elsevier Ltd.

  17. LANDSAT-D project ADDS/LAS. Scrounge interface control document

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The content and format of all data to be exchanged between the Applications Developmental data System (ADDS) and the LANDSAT-D Assessment System (LAS) for satisfaction of early access thematic mapper product generation requirements is specified. The ADDS provides partially processed TM data tapes on CCT's. The LANDSAT-D Assessment System processes the TM data to fully processed data tapes on 6250 bpi computer compatible tapes and provides required film data products.

  18. Comenditic and pantelleritic ash-flow tuffs from Volcan Las Navajas, Nayarit, Mexico

    SciTech Connect

    Nelson, S.A.; Hebre, J.A.

    1985-01-01

    Two distinctive ash-flow tuffs occur around the base of Volcan Las Navajas, a Pleistocene trachyte - peralkaline rhyolite center located in the northwestern segment of the Mexican Volcanic belt. The lower ash-flow unit is locally up to 65 m thick, is lithic rich and contains pumice blocks of comenditic rhyolite. The unit is not extensively exposed, and thus its areal extent and volume cannot be determined. Its chemical characteristics and stratigraphic relationship to other products erupted from Las Navajas suggest that it is related to the formation of the older of the two calderas which occur on Las Navajas. Unconformably overlying this unwelded ash-flow is a pantelleritic airfall pumice unit which is locally welded. This airfall unit is conformably overlain by a welded as-flow tuff that contains fiamme of pantelleritic composition (72 %SiO/sub 2/, 8% FeO*, 900 ppm Zr, agpaitic index of 1.7) as well as pumice blocks that show evidence of various degrees of mixing between pantellerite and trachyte. This suggests eruption from a chemically zoned magma chamber. This unit is locally up to 20 m thick, although its top has been removed by erosion. It is found on all sides of Las Navajas except on the south where it may be covered by Volcan Sanganguey, a Pleistocene to Recent calc-alkaline volcano. The welded ash-flow has been dated by K - Ar at 0.2+/-0.1 m.y. Stratigraphically and chemically this ash-flow appears to be related to the formation of younger of the two calderas.

  19. Solar hot water system installed at Las Vegas, Nevada. Final report

    SciTech Connect

    1981-01-01

    The solar hot water system installed at LaQuinta Motor Inn Inc., at Las Vegas, Nevada is described. The Inn is a three-story building with a flat roof for installation of the solar panels. The system consists of 1200 square feet of liquid flat plate collectors, a 2500 gallon insulated vertical steel storage tank, two heat exchangers and pumps and controls. The system was designed to supply approximately 74 percent of the total hot water load.

  20. Nondegraded metabolites arising from the biodegradation of commercial linear alkylbenzenesulfonate (LAS) surfactants in a laboratory trickling filter

    SciTech Connect

    Koelbener, P.; Baumann, U.; Leisinger, T.; Cook, A.M. |

    1995-04-01

    The degradation of a commercial linear alkylbenzenesulfonate (LAS) surfactant was examined kinetically in a trickling filter, which allowed simultaneous chemical determinations in the aqueous phase (e.g., DOC) and in the gas phase (CO{sub 2}). About 60% of the carbon applied as LAS was released as CO{sub 2}, whereas 15% remained as DOC in the eluate of acclimated trickling filters. The biomass was analyzed after the experiment, and it was found to have sorbed about 23 mg LAS/g of dry biomass; this represented about 3% of the LAS applied to the filter. The LAS and the eluates from the trickling filter were further analyzed by HPLC and UV and IR spectrometry. The residual carbon from acclimated filters contained no LAS-like material (HPLC), which was obviously subject to quantitative biotransformation. The residual material comprised > 50 polar metabolites, some of whose UV spectra differed from that of LAS, and most or all of which were sulfonated. These nondegraded metabolites included carboxylated dialkyltetralinesulfonates and sulfophenylcarboxylates. These residual materials showed no detectable toxicity to algae or Daphnia, and did not significantly lower the surface tension of water.

  1. The Las Vegas Valley Seismic Response Project: Ground Motions in Las Vegas Valley from Nuclear Explosions at the Nevada Test Site

    SciTech Connect

    Rodgers, A; Tkalcic, H; McCallen, D

    2005-03-18

    Between 2001-2004 the Las Vegas Seismic Response Project has sought to understand the response of Las Vegas Valley (LVV) to seismic excitation. In this study, the author report the findings of this project with an emphasis on ground motions in LVV from nuclear explosions at the Nevada Test Site (NTS). These ground motions are used to understand building structural response and damage as well as human perception. Historical nuclear explosion observations are augmented with earthquake recordings from a temporary deployment of seismometers to improve spatial coverage of LVV. The nuclear explosions were conducted between 1968 and 1989 and were recorded at various sites within Las Vegas. The data from past nuclear tests were used to constrain ground motions in LVV and to gain a predictive capability of ground motions for possible future nuclear tests at NTS. Analysis of ground motion data includes peak ground motions (accelerations and velocities) and amplification of basin sites relative to hard rock sites (site response). Site response was measured with the Standard Spectral Ratios (SSR) technique relative to hard rock reference sites on the periphery of LVV. The site response curves indicate a strong basin amplification of up to a factor of ten at frequencies between 0.5-2 Hz. Amplifications are strongest in the central and northern portions of LVV, where the basin is deeper than 1 km based on the reported basin depths of Langenheim et al (2001a). They found a strong correlation between amplification and basin depth and shallow shear wave velocities. Amplification below 1 Hz is strongly controlled by slowness-averaged shear velocities to depths of 30 and 100 meters. Depth averaged shear velocities to 10 meters has modest control of amplifications between 1-3 Hz. Modeling reveals that low velocity material in the shallow layers (< 200 m) effectively controls amplification. They developed a method to scale nuclear explosion ground motion time series to sites around LVV

  2. Quantifying multi-temporal urban development characteristics in Las Vegas from Landsat and ASTER data

    USGS Publications Warehouse

    Xian, G.; Crane, M.; McMahon, C.

    2008-01-01

    Urban development has expanded rapidly in Las Vegas, Nevada of the United States, over the last fifty years. A major environmental change associated with this urbanization trend is the transformation of the landscape from natural cover types to increasingly anthropogenic impervious surface. This research utilizes remote sensing data from both the Landsat and Terra-Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instruments in conjunction with digital orthophotography to estimate urban extent and its temporal changes by determining sub-pixel impervious surfaces. Percent impervious surface area has shown encouraging agreement with urban land extent and development density. Results indicate that total urban land-use increases approximately 110 percent from 1984 to 2002. Most of the increases are associated with medium-to high-density urban development. Places having significant increases in impervious surfaces are in the northwestern and southeastern parts of Las Vegas. Most high-density urban development, however, appears in central Las Vegas. Impervious surface conditions for 2002 measured from Landsat and ASTER satellite data are compared in terms of their accuracy.

  3. Surficial geology and distribution of post-impoundment sediment in Las Vegas Bay, Lake Mead

    USGS Publications Warehouse

    Twichell, David C.; Cross, VeeAnn A.; Rudin, Mark J.; Parolski, Kenneth F.; Rendigs, Richard R.

    2001-01-01

    Sidescan sonar imagery and seismic-reflection profiles were collected in the northwestern part of Las Vegas Bay to map the distribution and volume of sediment that has accumulated in this part of Lake Mead since impoundment. The mapping suggests that three ephemeral streams are the primary source of this sediment, and of these, Las Vegas Wash is the largest. Two deltas off the mouth of Las Vegas Wash formed at different lake elevations and account for 41% of the total volume of post-impoundment sediment within the study area. Deltas off the other two washes (Gypsum and Government) account for only 6% of the total volume. The sediment beyond the front of the deltas is primarily mud, and it only occurs in valley floors, where it forms a flat-lying blanket that is mostly less than 1.5 m thick. Although a thin layer, the fine-grained sediment accounts for approximately 53% of the total post-impoundment sediment volume of 5.7 x 106 m3 that has accumulated in the study area. This sediment appears to have been transported several kilometers from the river sources by density flows.

  4. Investigating Remotely Sensed Evapotranspiration in the Las Conchas and Old Fires

    NASA Astrophysics Data System (ADS)

    Poon, P.; Stewart, C.; Kinoshita, A. M.

    2015-12-01

    Wildfires significantly alter landscapes and can contribute to observed changes in hydrology. Evapotranspiration (ET) contributes significantly to the hydrologic cycle, however, there are limited studies on the impacts of fire on this variable. Using remote sensing derived products, this study explores the spatial variability of ET (specifically, the operational Simplified Surface Energy Balance (SSEBop)) within the 2011 Las Conchas Fire, New Mexico and the 2003 Old Fire, California. Following the Las Conchas Fire, spatial ET is compared with two ground-based meteorological stations and two nearby unburned stations. In the Old Fire, a simple water balance approach is used to approximate and compare watershed-scale ET pre- and post-fire. Preliminary analysis with SSEBop in Las Conchas shows relatively similar precipitation patterns while post-fire ET appears altered within high, moderate, and low burn severity areas. We will continue to evaluate the relation between post-fire ET and characteristics such as land cover, land surface temperature, and precipitation. This analysis will provide information on the application of spatial ET products to improve post-fire hydrologic estimates.

  5. Origen de los rayos cósmicos a las más altas energías

    NASA Astrophysics Data System (ADS)

    Horvath, J. E.; Gouveia dal Pino, E. M.; Medina Tanco, G. A.

    Discutimos en este trabajo la identificación de las fuentes de rayos cósmicos de las más altas energías observadas (E >= 1020 eV). Presentamos los resultados de varias simulaciones numéricas 3-D donde se calcula explícitamente el ángulo de desviación α del primario por efecto de los campos magnéticos ambientes. Con estos resultados investigamos las hipótesis de un origen extragaláctico local y halo galáctico.

  6. Variaciones seculares de período en las RR Lyrae de ω~Centauri

    NASA Astrophysics Data System (ADS)

    Marraco, H. G.; Milesi, G. E.

    Utilizando 689 observaciones de 35 estrellas RR Lyrae del cúmulo globular ω Centauri hemos obtenido nuevas determinaciones de sus períodos y sus correspondientes variaciones seculares. Las observaciones fueron obtenidas de la literatura con la excepción de un grupo 66 determinaciones que se presentan por vez primera aquí. Utilizando el parámetro testigo σ descripto en Marraco & Muzzio (Publ. Astron. Soc. Pacific 92, 700, 1980), hemos realizado un ajuste bidimensional en P y β (donde β es la variación secular del período). Con este fin la totalidad de las 689 observaciones fueron llevadas a un sistema fotométrico común. Para esto se realizó un cuidadoso análisis de los numerosos errores en la identificación de las estrellas de las series de comparación. Los resultados de los ajustes bidimensionales fueron analizados utilizando técnicas de procesamiento de imágenes. Con este fin el parámetro de ajuste σ fue representado como función de P y β. En las imágenes resultantes se buscaron los mínimos y al menor de ellos se lo aceptó como período instantáneo verdadero y su variación secular β. La determinación precisa de cada parámetro se realizó mediante ajuste de gaussianas y se determinaron sus errores. A modo de ejemplo la variable #8 fue analizada en una matriz de 501 × 501 elementos representando el parámetro σ para valores comprendidos entre 0,521034 < P < 0,521534 dias y -150×10-10 < β < +150×10-10 dias/dia. El mejor período instantáneo (correspondiente a la época DJ=2.426.908) y su variación secular son P = 0,5212859±0,0000001 días y β 14,012±,010×10-10 días/día respectivamente. Con estos valores el parámetro testigo resulta σ= 0,127 . Si no se tiene en cuenta la variación secular del período y se busca aquél de mejor ajuste para β = 0, se obtiene P = 0,5212960 días, pero entonces el parámetro de ajuste resulta tan alto como σ = 0,23 .

  7. Final Report for the Arroyo Las Positas Maintenance Impact Study, Lawrence Livermore National Laboratory

    SciTech Connect

    van Hattem, M; Paterson, L

    2006-01-12

    In 2000, the Lawrence Livermore National Laboratory's (LLNL) Environmental Protection Department, in coordination with Plant Engineering (PE), began dredging sections of the Arroyo Las Positas (ALP) to alleviate concerns about flooding of sensitive facilities within the mainsite of Lawrence Livermore National Laboratory. In order to reduce potential impacts on the federally threatened California red-legged frog (Rana aurora draytonii), LLNL proposed to dredge sections of the ALP in a ''checkerboard pattern'', resulting in a mosaic of open water habitat and vegetated sections (Figure 1). The Arroyo Las Positas Management Plan (Plan) was coordinated with both state and federal agencies including the U.S. Fish and Wildlife Service (USFWS), California Department of Fish and Game (CDF&G), San Francisco Regional Water Quality Control Board (SFRWQCB), and the Army Corp of Engineers (ACOE). Water Discharge Requirements (WDRs) were issued for this project on December 30, 1999 (Order No. 99-086) by the SFRWQCB. Provision 19 of the WDRs outlined a five-year (2000 through 2004) Maintenance Impact Study (MIS) that LLNL began in coordination with dredging work that was conducted as part of the Arroyo Las Positas Management Plan. Provision 20 of these WDRs requires LLNL to submit a final report of the results of the Maintenance Impact Study for this project to the SFRWQCB. The purpose of this report is to present the results of the Maintenance Impact Study for Arroyo Las Positas and meet the requirements of Provision 20. A description of the annual monitoring included in this Maintenance Impact Study is included in the methods section of this report. Initially the Plan called for dredging the entire length of the Arroyo Las Positas (approximately 6,981 linear feet) over a 5-year period to minimize temporal impacts on the California red-legged frog. Dredging occurred in 2000 ({approx}1,300 ft.), 2001 ({approx}800 ft.), and 2002 ({approx}1,200 ft.), which constituted approximately

  8. An Aerial Radiological Survey of Selected Areas of the City of North Las Vegas

    SciTech Connect

    Piotr Wasiolek

    2008-06-01

    As part of the proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory-Nellis (RSL-Nellis) conducted an aerial radiological survey of selected areas of the city of North Las Vegas for the purpose of mapping natural radiation background and locating any man-made radioactive sources. Survey areas were selected in collaboration with the City Manager's office and included four separate areas: (1) Las Vegas Motor Speedway (10.6 square miles); (2) North Las Vegas Downtown Area (9.2 square miles); (3) I-15 Industrial Corridor (7.4 square miles); and (4) Future site of University of Nevada Las Vegas campus (17.4 square miles). The survey was conducted in three phases: Phase 1 on December 11-12, 2007 (Areas 1 and 2), Phase 2 on February 28, 2008 (Area 3), and Phase 3 on March 19, 2008 (Area 4). The total completed survey covered a total of 44.6 square miles. The flight lines (without the turns) over the surveyed areas are presented in Figures 1, 2, 3, and 4. A total of eight 2.5-hour-long flights were performed at an altitude of 150 ft above ground level (AGL) with 300 feet of flight-line spacing. Water line and test line flights were conducted over the Lake Mead and Government Wash areas to ensure quality control of the data. The data were collected by the AMS data acquisition system (REDAR V) using an array of twelve 2-inch x 4-inch x 16-inch sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Data, in the form of gamma energy spectra, were collected continually (every second) over the course of the survey and were geo-referenced using a differential Global Positioning System. Collection of spectral data allows the system to distinguish between ordinary fluctuations in natural background radiation levels and the signature produced by man-made radioisotopes. Spectral data can also be used to identify specific radioactive isotopes. As a courtesy service, with

  9. Investigaccion-accion en la sala de clases sobre las creencias de la cultura de la ciencia de un grupo de estudiantes universitarios y su relacion reciproca con el aprendizaje de las ciencias biologicas

    NASA Astrophysics Data System (ADS)

    Cordova-Santiago, Lizzette Astrid

    La investigacion---accion que se llevo a cabo en la sala de clases tenia como punto de partida las creencias de la cultura de la ciencia de un grupo de estudiantes universitarios para luego examinar sus implicaciones en el proceso de aprendizaje de las Ciencias Biologicas. ¿Que se supone que hagan las creencias en relacion con el aprendizaje? ¿En que consiste incorporar este aspecto a la practica educativa universitaria? Utilizando el modelo de Kemmis y McTaggart (1987) la investigacion-accion se planteo como un proceso dinamico en cuatro momentos en espiral constituidos por la planificacion, la accion, la observacion y la reflexion. Cada una de las fases tuvo una intencion retrospectiva y prospectiva formando una espiral de autorreflexion del conocimiento y la accion. Se llevaron a cabo audio grabaciones en clases y analisis de documentos. Ademas, la profesora-investigadora hizo un portafolio para reflexionar sobre las creencias de la cultura de la ciencia que tienen los estudiantes y las creencias del aprendizaje que tiene la profesora y sobre como la comprension de estos elementos ayudo a mejorar su practica educativa a traves del tiempo. Los resultados obtenidos apuntan a que las creencias de la cultura de la ciencia que tiene el grupo de estudiantes son diversas. Ellos si creen que la ciencia tiene una cultura la cual describieron como: complicada y desconocida que evoluciona constantemente, que es un conjunto de metodos, que es altamente tecnologica, que resuelve problemas de salud, ayuda a interpretar la realidad del mundo que los rodea y su origen y que existen unas intersecciones entre la ciencia y el poder. Sobre las creencias del proceso de aprendizaje de la profesora-investigadora, estas senalan que el modelaje de actores, la vision de la academia que tiene ella asi como la participacion y negociacion entre todos los involucrados en el proceso educativo, son factores que inciden en el proceso de aprendizaje.

  10. Long-term assessment of ultrafine particles on major roadways in Las Vegas, Nevada and Detroit, Michigan

    EPA Science Inventory

    This is a presentation at the National Air Monitoring conference, given at the request of OAQPS partners. The presentation will cover ultrafine particle data collected at three locations - Las Vegas, Detroit, and Research Triangle Park.

  11. Seismic Data for Evaluation of Ground Motion Hazards in Las Vegas in Support of Test Site Readiness Ground Motion

    SciTech Connect

    Rodgers, A

    2008-01-16

    In this report we describe the data sets used to evaluate ground motion hazards in Las Vegas from nuclear tests at the Nevada Test Site. This analysis is presented in Rodgers et al. (2005, 2006) and includes 13 nuclear explosions recorded at the John Blume and Associates network, the Little Skull Mountain earthquake and a temporary deployment of broadband station in Las Vegas. The data are available in SAC format on CD-ROM as an appendix to this report.

  12. A brief hydrologic appraisal of the July 3-4, 1975, flash flood in Las Vegas Valley, Nevada

    USGS Publications Warehouse

    Katzer, T.L.; Glancy, Patrick A.; Harmsen, Lynn

    1976-01-01

    Heavy thunderstorm precipitation on the afternoon of July 3, 1975, between metropolitan Las Vegas and the mountains to the south, west, and north, caused flash flooding in the city area. Total storm precipitation equaled or exceeded 3 inches (76 mm) in some areas. The total storm yield on the area of significant runoff was probably between 20,000 and 25,000 acre-feet (2.5 x 107 m3 and 3.1 x 107 m3) of water. Of this amount, probably less than 3,000 acre-feet (37 x 106 m3) flowed directly to Lake Mead. Peak flows of Tropicana Wash, Flamingo Wash, Las Vegas Creek, and Las Vegas Wash were the highest ever determined. Flooding caused the loss of two lives and inflicted extensive property damage. Total damage was reportedly estimated by the Clark County Flood Control District at $4-5 million. Problems associated with sediment erosion, transportation, and deposition occurred throughout the flooded area. An unknown amount of the material transported during the flood was deposited in Lake Mead near the mouth of Las Vegas Wash. Lateral erosion appeared more prominent than vertical erosion along most major channels, except on Las Vegas Wash at Northshore Road where downcutting threatened the loss of the highway. Sediment deposits were particularly noticeable and troublesome in Flamingo Wash at Caesars Palace parking lot and on the Winterwood Golf Course near the junction of Flamingo Wash and Las Vegas Wash.

  13. The Liege Acromegaly Survey (LAS): a new software tool for the study of acromegaly.

    PubMed

    Petrossians, Patrick; Tichomirowa, Maria A; Stevenaert, Achile; Martin, Didier; Daly, Adrian F; Beckers, Albert

    2012-06-01

    Acromegaly is a chronic rare disease associated with negative pathological effects on multiple systems and organs. We designed a new informatics tool to study data from patients with acromegaly, the Liege Acromegaly Survey (LAS). This relational database permits the inclusion of anonymous historical and prospective data on patients and includes pathophysiology, clinical features, responses to therapy and long term outcomes of acromegaly. We deployed the LAS in a validation study at a single center in order to study the characteristics of patients with acromegaly diagnosed at our center from 1970-2011. A total of 290 patients with acromegaly were included (147 males and 143 females). There was a linear relationship between age at diagnosis and the date of diagnosis, indicating that older patients are being diagnosed with acromegaly more frequently. A majority presented with macroadenomas (77.5%) and the median diameter was 14 mm. Patients with macroadenomas were significantly younger than patients with microadenomas (P=0.01). GH values at diagnosis decreased with the age of the patients (P=0.01) and there was a correlation between GH values and tumor size at diagnosis (P=0.02). No correlation existed between insulin-like growth factor 1 (IGF-1) levels and tumor characteristics. The prevalence of diabetes was 21.4% in this population and 41.0% had hypertension. The presence of hypertension and diabetes were significantly associated with one another (P<0.001). There was a linear relation between initial GH and IGF-1 levels at diagnosis and those obtained during SSA analog treatment and the lowest GH and IGF-1 values following SSA therapy were obtained in older patients (GH: P<0.001; IGF-1: P<0.001). The LAS is a new relational database that is feasible to use in the clinical research setting and permits ready pooling of anonymous patient data from multiple study sites to undertake robust statistical analyses of clinical and therapeutic characteristics.

  14. Elevation Changes of LAS, East Antarctica, Derived From ICESat and CryoSat-2 Altimetric Data

    NASA Astrophysics Data System (ADS)

    Chen, L.; Xie, H.; Hai, G.; Liu, S.; Liu, J.; Tong, X.; Li, R.

    2015-12-01

    Understanding of mass changes of the Antarctic ice sheet is essential for sea level rise study. A research effort has been made to estimate elevation mass changes at Lambert Glacier-Amery Ice Shelf System (LAS), East Antarctica using ICESat data of 2004-2008 and Cryosat-2 data of 2010-2015. A repeat-tack processing method that includes a trend and the first order terrain terms is applied to repeat-track points of all ICESat Campaigns of 2004-2008. The estimated change rate in LAS from 2004-2008 is 3.14±4.13 Gt yr-1. At the basin level, two basins show a combined positive trend of 8.16±2.96 Gt yr-1 while other four basins a combined negative trend of -5.39±6.04 Gt yr-1. Cryosat-2 altimeter works in three modes with the "synthetic aperture interferometer mode" (SARIn) and "low-resolution mode" (LRM) in LAS. Our data coverage is from 2010 to 2015. Cryosat-2 ground tracks do not maintain repeated points. We further divide the entire area into a grid of 5km by 5km. Then we estimate the elevation change rate in each grid cell using a least-squares fitting model with a trend and a second order polynomial. We found that the quality of the estimates is correlated with slopes of cells. The progress of the CryoSat-2 data processing result as well as the analysis with the existing ICESat result will be presented. An integrated model of both ICESat and CryoSat-2 data processing will be developed.

  15. An Aerial Radiological Survey of the Las Vegas Strip and Adjacent Areas

    SciTech Connect

    Wasiolek, Piotr

    2009-02-01

    As proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory–Nellis (RSL-Nellis) conducted an aerial radiological survey of the Las Vegas Strip and adjacent areas on December 29, 2008. This survey was one of the bi-annual surveys carried in support of the city of Las Vegas Police Department (LVPD) before significant events on the Las Vegas Strip: e.g., the annual New Year’s Eve and July Fourth celebrations. The AMS operation and appropriate law enforcement agencies selected this area as an appropriate urban location to exercise AMS capability for mapping environmental radiation and searching for man-made radioactive sources. The surveys covered approximately 11 square miles. Each survey required a 2.5-hour-long flight, performed at an altitude of 300 ft above ground level (AGL) at a line spacing of 600 ft. Water line and test line flights are conducted over the Lake Mead and Government Wash areas to determine the non-terrestrial background contributed by aircraft, radon, and cosmic activity, and to determine the altitude-dependent air mass correction. The data were collected by the AMS data acquisition system (REDAR V) using an array of twelve 2" x 4" x 16" sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Gamma energy spectral data were collected second-by-second over the survey area. This spectral data allows the system to distinguish between natural terrestrial background contributions and man-made radioisotope contributions. Spectral data can also be used to identify specific man-made radioactive isotopes. Data geo-locations were determined with a Real-Time Differential Global Positioning System (RDGPS).

  16. Interferograms showing land subsidence and uplift in Las Vegas Valley, Nevada, 1992-99

    USGS Publications Warehouse

    Pavelko, Michael T.; Hoffmann, Jorn; Damar, Nancy A.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the Nevada Department of Conservation and Natural Resources-Division of Water Resources and the Las Vegas Valley Water District, compiled 44 individual interferograms and 1 stacked interferogram comprising 29 satellite synthetic aperture radar acquisitions of Las Vegas Valley, Nevada, from 1992 to 1999. The interferograms, which depict short-term, seasonal, and long-term trends in land subsidence and uplift, are viewable with an interactive map. The interferograms show that land subsidence and uplift generally occur in localized areas, are responsive to ground-water pumpage and artificial recharge, and, in part, are fault controlled. Information from these interferograms can be used by water and land managers to mitigate land subsidence and associated damage. Land subsidence attributed to ground-water pumpage has been documented in Las Vegas Valley since the 1940s. Damage to roads, buildings, and other engineered structures has been associated with this land subsidence. Land uplift attributed to artificial recharge and reduced pumping has been documented since the 1990s. Measuring these land-surface changes with traditional benchmark and Global Positioning System surveys can be costly and time consuming, and results typically are spatially and temporally sparse. Interferograms are relatively inexpensive and provide temporal and spatial resolutions previously not achievable. The interferograms are viewable with an interactive map. Landsat images from 1993 and 2000 are viewable for frames of reference to locate areas of interest and help determine land use. A stacked interferogram for 1992-99 is viewable to visualize the cumulative vertical displacement for the period represented by the individual interferograms. The interactive map enables users to identify and estimate the magnitude of vertical displacement, visually analyze deformation trends, and view interferograms and Landsat images side by side. The

  17. An Aerial Radiological Survey of the City of North Las Vegas (Downtown) and the Motor Speedway

    SciTech Connect

    Piotr Wasiolek

    2007-12-01

    As part of the proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory-Nellis (RSL-Nellis) conducted an aerial radiological survey on December 11-12, 2007, with the purpose of mapping natural radiation background and locating any man-made radioactive sources. The survey covered 19.4 square miles (9.2 square miles over the downtown area of the City of North Las Vegas and 10.2 square miles over the Las Vegas Motor Speedway [LVMS]). The flight lines over the surveyed areas are presented in Figures 1 and 2. A total of four 2.5-hour-long flights were performed at an altitude of 150 ft above ground level (AGL) with 300 ft of flight line spacing. Water line and test line flights were conducted over the Lake Mead and Government Wash areas to ensure quality control of the data. The data were collected by the AMS data acquisition system-REDAR V using an array of twelve 2-inch x 4-inch x 16-inch sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Data in the form of gamma energy spectra were collected continually (every second) over the course of the survey and were geo-referenced using a differential Global Positioning System. Collection of spectral data allows the system to distinguish between ordinary fluctuations in natural background radiation levels and the signature produced by man-made radioisotopes sources. Spectral data can also be used to identify specific radioactive isotopes. As a courtesy service with the approval of the U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office, RSL-Nellis is providing this summary to the office of the Mayor of City of North Las Vegas and LVMS security along with the gross counts-based exposure rate and man-made counts maps.

  18. Las Cumbres Observatory: Building a global telescope network from the ground up

    NASA Astrophysics Data System (ADS)

    Gomez, E. L.

    2015-03-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) are building a global network of telescopes which will be available to both professional scientists and the science curious public. This telescope network will be global and so will the community, therefore all aspects of the endeavour must be online and self-sustaining - from the observing software to the analysis tools. During 2012 LCOGT have deployed the first 1-meter telescopes, and launched a citizen science project using LCOGT data, Agent Exoplanet, as well as many other online resources for anyone to use as they explore astronomy.

  19. Crystal Structure of the LasA Virulence Factor from Pseudomonas aeruginosa: Substrate Specificity and Mechanism of M23 Metallopeptidases

    SciTech Connect

    Spencer, James; Murphy, Loretta M.; Conners, Rebecca; Sessions, Richard B.; Gamblin, Steven J.

    2010-09-21

    Pseudomonas aeruginosa is an opportunist Gram-negative bacterial pathogen responsible for a wide range of infections in immunocompromized individuals and is a leading cause of mortality in cystic fibrosis patients. A number of secreted virulence factors, including various proteolytic enzymes, contribute to the establishment and maintenance of Pseudomonas infection. One such is LasA, an M23 metallopeptidase related to autolytic glycylglycine endopeptidases such as Staphylococcus aureus lysostaphin and LytM, and to DD-endopeptidases involved in entry of bacteriophage to host bacteria. LasA is implicated in a range of processes related to Pseudomonas virulence, including stimulating ectodomain shedding of the cell surface heparan sulphate proteoglycan syndecan-1 and elastin degradation in connective tissue. Here we present crystal structures of active LasA as a complex with tartrate and in the uncomplexed form. While the overall fold resembles that of the other M23 family members, the LasA active site is less constricted and utilizes a different set of metal ligands. The active site of uncomplexed LasA contains a five-coordinate zinc ion with trigonal bipyramidal geometry and two metal-bound water molecules. Using these structures as a starting point, we propose a model for substrate binding by LasA that explains its activity against a wider range of substrates than those used by related lytic enzymes, and offer a catalytic mechanism for M23 metallopeptidases consistent with available structural and mutagenesis data. Our results highlight how LasA is a structurally distinct member of this endopeptidase family, consistent with its activity against a wider range of substrates and with its multiple roles in Pseudomonas virulence.

  20. Machines, medication, modulation: circuits of dependency and self-care in Las Vegas.

    PubMed

    Schüll, Natasha Dow

    2006-06-01

    The intensive entertainment infrastructure of Las Vegas is overlaid with a robust therapeutic network for those who become addicted to its technologies. Although the objectives of gambling machines and addiction therapeutics are seemingly at odds--the first work to encourage play, the second to stop it--both gear their interventions around a model of the self as a continuum of behavioral potentials that can be externally modulated. For compulsive gamblers implicated in this circuit of modulation, pharmaceutical drugs that have been prescribed to dampen cravings for machine play sometimes function as intensifiers of its effects. Caught in an intractable play between technologies of harm and technologies of care, recovering gambling addicts are challenged to assemble a technical array through which they can maintain balance; health itself, for these individuals, becomes a state of managed dependency. This essay explores the shifting terms and changing stakes of subjectivity and health in the contemporary United States by way of ethnographic research on compulsive gamblers who live and work in Las Vegas. The analysis draws on interviews with gamblers as well as on observations in local self-help groups, directed group therapy sessions, and chat rooms of Internet recovery Web sites.

  1. Excess air during aquifer storage and recovery in an arid basin (Las Vegas Valley, USA)

    NASA Astrophysics Data System (ADS)

    Solomon, D. Kip; Cole, Erin; Leising, Joseph F.

    2011-02-01

    The Las Vegas Valley Water District in Nevada, USA, has operated an artificial recharge (AR) program since 1989. In summer 2001, observations of gas exsolving from tap water prompted a study that revealed total dissolved gas (TDG) pressures approaching 2 atm with a gas composition that it is predominantly air. Measurements of TDG pressure at well heads and in the distribution system indicated two potential mechanisms for elevated TDG pressures: (1) air entrainment during AR operations, and (2) temperature changes between the winter recharge season and the summer withdrawal season. Air entrainment during pumping was investigated by intentionally allowing the forebay (upstream reservoir) of a large pumping station to drawdown to the point of vortex formation. This resulted in up to a 0.7 atm increase in TDG pressure. In general, the solubility of gases in water decreases as the temperature increases. In the Las Vegas Valley, water that acquired a modest amount of dissolved gas during winter artificial recharge operations experienced an increase in dissolved gas pressure (0.04 atm/°C) as the water warmed in the subsurface. A combination of air entrainment during AR operations and its amplification by temperature increase after recharge can account for most of the observed amounts of excess gas at this site.

  2. Seasonal subsidence and rebound in Las Vegas Valley, Nevada, observed by synthetic aperture radar interferometry

    USGS Publications Warehouse

    Hoffmann, J.; Zebker, H.A.; Galloway, D.L.; Amelung, F.

    2001-01-01

    Analyses of areal variations in the subsidence and rebound occurring over stressed aquifer systems, in conjunction with measurements of the hydraulic head fluctuations causing these displacements, can yield valuable information about the compressibility and storage properties of the aquifer system. Historically, stress-strain relationships have been derived from paired extensometer/piezometer installations, which provide only point source data. Because of the general unavailability of spatially detailed deformation data, areal stress-strain relations and their variability are not commonly considered in constraining conceptual and numerical models of aquifer systems. Interferometric synthetic aperture radar (InSAR) techniques can map ground displacements at a spatial scale of tens of meters over 100 km wide swaths. InSAR has been used previously to characterize larger magnitude, generally permanent aquifer system compaction and land subsidence at yearly and longer timescales, caused by sustained drawdown of ground-water levels that produces intergranular stresses consistently greater than the maximum historical stress. We present InSAR measurements of the typically small-magnitude, generally recoverable deformations of the Las Vegas Valley aquifer system occurring at seasonal timescales. From these we derive estimates of the elastic storage coefficient for the aquifer system at several locations in Las Vegas Valley. These high-resolution measurements offer great potential for future investigations into the mechanics of aquifer systems and the spatial heterogeneity of aquifer system structure and material properties as well as for monitoring ongoing aquifer system compaction and land subsidence.

  3. INTRAVAL Phase 2: Modeling testing at the Las Cruces Trench Site

    SciTech Connect

    Hills, R.G.; Wierenga, P.J.; Luis, S.; McLaughlin, D.; Rockhold, M.; Xiang, J.; Scanlon, B.; Wittmeyer, G.

    1994-01-01

    Several field experiments have been performed by scientists from the University of Arizona and New Mexico State University at the Las Cruces Trench Site to provide data tc test deterministic and stochastic models for water flow and solute transport. These experiments were performed in collaboration with INTRAVAL, an international effort toward validation of geosphere models for the transport of radionuclides. During Phase I of INTRAVAL, qualitative comparisons between experimental data and model predictions were made using contour plots of water contents and solute concentrations. Detailed quantitative comparisons were not made. To provide data for more rigorous model testing, a third Las Cruces Trench experiment was designed by scientists from the University of Arizona and New Mexico State University. Modelers from the Center for Nuclear Waste Regulatory Analysis, Massachusetts Institute of Technology, New Mexico State University, Pacific Northwest Laboratory, and the University of Texas provided predictions of water flow and tritium transport to New Mexico State University for analysis. The corresponding models assumed soil characterizations ranging from uniform to deterministically heterogeneous to stochastic. This report presents detailed quantitative comparisons to field data.

  4. Late quaternary environmental changes in the upper Las Vegas valley, Nevada

    NASA Astrophysics Data System (ADS)

    Quade, Jay

    1986-11-01

    Five stratigraphic units and five soils of late Pleistocene to Holocene age crop out in dissected badlands on Corn Creek Flat, 30 km northwest of Las Vegas, Nevada, and at Tule Springs, nearer to Las Vegas. The record is dominantly fluvial but contains evidence of several moister, marsh-forming periods: the oldest (Unit B) dates perhaps to the middle Wisconsin, and the more widespread Unit D falls between 30,000 and 15,000 yr B.P. Unit D therefore correlates with pluvial maximum lacustrine deposits elsewhere in the Great Basin. Standing water was not of sufficient depth or extent during either period to form lake strandlines. Between 14,000 and 7200 yr B.P. (Unit E), standing surface water gradually decreased, a trend also apparent in Great Basin pluvial lake chronologies during the same period. Groundwater carbonate cementation and burrowing by cicadas (Cicadae) accompany the moist-phase units. After 7200 yr B.P., increased wind action, decreased biotic activity, and at least 25 m of water-table lowering accompanied widespread erosion of older fine-grained deposits. Based on pack-rat midden and pollen evidence, this coincides with major vegetation changes in the valley, from sagebrush-dominated steppe to lower Mohave desertscrub.

  5. On an LAS-integrated soft PLC system based on WorldFIP fieldbus.

    PubMed

    Liang, Geng; Li, Zhijun; Li, Wen; Bai, Yan

    2012-01-01

    Communication efficiency is lowered and real-time performance is not good enough in discrete control based on traditional WorldFIP field intelligent nodes in case that the scale of control in field is large. A soft PLC system based on WorldFIP fieldbus was designed and implemented. Link Activity Scheduler (LAS) was integrated into the system and field intelligent I/O modules acted as networked basic nodes. Discrete control logic was implemented with the LAS-integrated soft PLC system. The proposed system was composed of configuration and supervisory sub-systems and running sub-systems. The configuration and supervisory sub-system was implemented with a personal computer or an industrial personal computer; running subsystems were designed and implemented based on embedded hardware and software systems. Communication and schedule in the running subsystem was implemented with an embedded sub-module; discrete control and system self-diagnosis were implemented with another embedded sub-module. Structure of the proposed system was presented. Methodology for the design of the sub-systems was expounded. Experiments were carried out to evaluate the performance of the proposed system both in discrete and process control by investigating the effect of network data transmission delay induced by the soft PLC in WorldFIP network and CPU workload on resulting control performances. The experimental observations indicated that the proposed system is practically applicable.

  6. Rock magnetic properties and ore microscopy of the iron ore deposit of Las Truchas, Michoacan, Mexico

    NASA Astrophysics Data System (ADS)

    Alva-Valdivia, L. M.; Urrutia-Fucugauchi, J.

    1998-02-01

    Iron ore and host rocks have been sampled (90 oriented samples from 19 sites) from the Las Truchas mine, western Mexico. A broad range of magnetic parameters have been studied to characterize the samples: saturation magnetization, Curie temperature, density, susceptibility, remanence intensity, Koenigsberger ratio, and hysteresis parameters. Magnetic properties are controlled by variations in titanomagnetite content, deuteric oxidation, and hydrothermal alteration. Las Truchas deposit formed by contact metasomatism in a Mesozoic volcano-sedimentary sequence intruded by a batholith, and titanomagnetites underwent intermediate degrees of deuteric oxidation. Post-mineralization hydrothermal alteration, evidenced by pyrite, epidote, sericite, and kaolin, seems to be the major event that affected the minerals and magnetic properties. Magnetite grain sizes in iron ores range from 5 to >200 μm, which suggest dominance of multidomain (MD) states. Curie temperatures are 580±5°C, characteristic of magnetite. Hysteresis parameters indicate that most samples have MD magnetite, some samples pseudo-single domain (PSD), and just a few single domain (SD) particles. AF demagnetization and IRM acquisition indicate that NRM and laboratory remanences are carried by MD magnetite in iron ores and PSD-SD magnetite in host rocks. The Koenigsberger ratio falls in a narrow range between 0.1 and 10, indicating the significance of MD and PSD magnetites.

  7. Ground-water conditions in Las Veags Valley, Clark County, Nevada; part 1 Hydrogeologic Framework

    USGS Publications Warehouse

    Plume, Russell W.

    1989-01-01

    This report describes the lithology, thickness, and extent of valley-fill deposits in Las Vegas Valley, Nev. This information will be used to develop a hydraulic model of the valley's ground-water system. Las Vegas Valley is a structural basin formed by bedrock that ranges in age from Precambrian through Miocene. Gravity data indicate that the deeper parts of the basin are filled with 3,000-5,000 feet of clastic sedimentary deposits that range in age from Miocene through Holocene. These deposits constitute the valley-fill aquifer and yield most of the water pumped in the valley. The upper 1,000 feet of this valley fill consist of coarse-grained deposits (sand and gravel), fine-grained deposits (silt and clay), and heterogeneous deposits that comprise either thinly interbedded coarse- and fine-grained deposits or mixtures of the two. Coarse-grained deposits, in places more than 1,000 feet thick, underlie the south and west sides of the valley and interfinger with fine-grained and heterogeneous deposits toward the center of the valley. Intervals of fairly thin heterogeneous deposits underlie parts of the valley, but they are not laterally persistent. The distribution of coarse-grained and fine-grained deposits in three depth zones of the valley fill (0-200 feet, 200-700 feet, and 700-1,000 feet) suggests that: (1) the Spring Mountains and McCullough Range were the major sources of clastic material for the valley fill; (2) Frenchman Mountain and the Las Vegas Range were emplaced later than the Spring Mountains; (3) the east side of the Spring Mountains, which was originally closer to the center of the valley, has receded westward because of erosion; and (4) shallow, fine-grained deposits (0-200 feet deep) are more susceptible to subsidence than deeper ones. The bedrock basin that underlies Las Vegas Valley consists of a deeply buried part that underlies most of the valley and a shallow bedrock surface on the west side of the valley. The deep part of the basin is

  8. Retention behavior of phenols, anilines, and alkylbenzenes in liquid chromatographic separations using subcritical water as the mobile phase.

    PubMed

    Yang, Y; Jones, A D; Eaton, C D

    1999-09-01

    The unique characteristic of subcritical water is its widely tunable physical properties. For example, the polarity (measured by dielectric constant) of water is significantly decreased by raising water temperature. At temperatures of 200-250 °C (under moderate pressure to keep water in the liquid state), the polarity of pure water is similar to that of pure methanol or acetonitrile at ambient conditions. Therefore, pure subcritical water may be able to serve as the mobile phase for reversed-phase separations. To investigate the retention behavior in subcritical water separation, the retention factors of BTEX (benzene, toluene, ethylbenzene, and m-xylene), phenol, aniline, and their derivatives have been determined using subcritical water, methanol/water, and acetonitrile/water systems. Subcritical water separations were also performed using alumina, silica-bonded C18, and poly(styrene-divinylbenzene) columns to study the influence of the stationary phase on analyte retention under subcritical water conditions.

  9. Enantioselective Metabolism of Chiral 3-Phenylbutyric Acid, an Intermediate of Linear Alkylbenzene Degradation, by Rhodococcus rhodochrous PB1

    PubMed Central

    Simoni, S.; Klinke, S.; Zipper, C.; Angst, W.; Kohler, H. E.

    1996-01-01

    Rhodococcus rhodochrous PB1 was isolated from compost soil by selective culture with racemic 3-phenylbutyric acid as the sole carbon and energy source. Growth experiments with the single pure enantiomers as well as with the racemate showed that only one of the two enantiomers, (R)-3-phenylbutyric acid, supported growth of strain PB1. Nevertheless, (S)-3-phenylbutyric acid was cometabolically transformed to, presumably, (S)-3-(2,3-dihydroxyphenyl)butyric acid (the absolute configuration at the C-3 atom is not known yet) by (R)-3-phenylbutyric acid-grown cells of strain PB1, as shown by (sup1)H nuclear magnetic resonance spectroscopy of the partially purified compound and gas chromatography-mass spectrometry analysis of the trimethylsilyl derivative. Oxygen uptake rates suggest that either 3-phenylpropionic acid or cinnamic acid (trans-3-phenyl-2-propenoic acid) is the substrate for aromatic ring hydroxylation. This view is substantiated by the fact that 3-(2,3-dihydroxyphenyl)propionic acid was a substrate for meta cleavage in cell extracts of (R)-3-phenylbutyric acid-grown cells of strain PB1. Gas chromatography-mass spectrometry analysis of trimethylsilane-treated ethyl acetate extracts of incubation mixtures showed that both the meta-cleavage product, 2-hydroxy-6-oxo-2,4-nonadiene-1,9-dicarboxylic acid, and succinate, a hydrolysis product thereof, were formed during such incubations. PMID:16535265

  10. Study of adjuvant effect of model surfactants from the groups of alkyl sulfates, alkylbenzene sulfonates, alcohol ethoxylates and soaps.

    PubMed

    Clausen, S K; Sobhani, S; Poulsen, O M; Poulsen, L K; Nielsen, G D

    2000-11-01

    The sodium salts of representatives of anionic surfactants, dodecylbenzene sulfonate (SDBS), dodecyl sulfate (SDS) and coconut oil fatty acids, and a nonionic surfactant, dodecyl alcohol ethoxylate, were studied for adjuvant effect on the production of specific IgE antibodies in mice. The surfactants were injected subcutaneously (sc) in concentrations of 1000, 100, 10 or 1 mg/l, respectively, together with 1 microg of ovalbumin (OVA). In addition, groups of mice received OVA in saline (control group) or in Al(OH)(3) (positive adjuvant control group). After the primary immunization the mice were boosted up to three times with OVA (0.1 microg sc) in saline. OVA-specific IgE antibodies were determined by the heterologous mouse rat passive cutaneous anaphylaxis test. The results were confirmed by a specific ELISA method. After the first booster, the Al(OH)(3) group and the 10 mg/l SDS group showed a statistically significant increase in OVA specific IgE levels. After two boosters, a statistically significant suppression in OVA-specific IgE production occurred with SDS (1000 mg/l), SDBS (1000 and 100 mg/l), coconut soap (1000 mg/l) and the alcohol ethoxylate (10 mg/l). This study suggests that a limited number of surfactants possess an adjuvant effect whereas all surfactants at certain levels can suppress specific IgE production.

  11. Competition between Methane and Alkylbenzenes for Electron Acceptors during Natural Attenuation of Crude Oil in the Subsurface

    NASA Astrophysics Data System (ADS)

    Bekins, B. A.; Amos, R. T.; Cozzarelli, I.; Voytek, M. A.

    2009-12-01

    At a crude-oil spill site near the town of Bemidji, MN, entrapped oil is present at residual saturations exceeding 10% in the vadose zone and floating at the water table at saturations of 30-60%. The degradable fraction of the light crude oil includes n-alkanes, aromatics, and alkyl-cyclohexanes. Together these compounds constitute a reduced carbon concentration at least 500 times greater than is present in the dissolved hydrocarbon groundwater plume comprised mainly of aromatics. Methanogenic degradation of the stationary oil body has been occurring for at least 20 years providing a continuous supply of methane emanating from the oil. Transport of methane away from the oil body occurs in both the vapor phase through the vadose zone and in the dissolved phase with the groundwater flow. Within the vadose zone the supply of oxygen and other electron acceptors from the surface is completely consumed by the process of methane oxidation in a zone 2-3 meters above the water table. In the groundwater, the 1 ppm contour of the methane plume extends beyond the 0.5 ppb contour for benzene, which is located at the aerobic/anaerobic boundary in the plume approximately 120 m downgradient of the oil body. Between 75 m and 120 m downgradient, methane concentrations decrease steadily from >0.6 mmol/L to <0.06 mmol/L, accompanied by increases in the δ13C-CH4 indicating that methane attenuation occurs through microbially-mediated oxidation. Anaerobic methane oxidation under iron-reducing conditions has recently been demonstrated by Beal et al. (Science, 325, 184, 2009) and is indicated at this site by several lines of evidence. In the methane oxidation zone, values of bioavailable Fe(III) extracted from the sediments averaged 8 mmol/kg (n=16), or >8 times the amount required to degrade 0.5 mmol methane, while all other electron acceptors together can account for complete oxidation of only 0.07 mmol (sulfate <0.06 mmol/L, dissolved oxygen <3 µmol/L, and nitrate <0.02 mmol/L). Active iron-reduction is indicated by dissolved Fe(II) >0.15 mmol/L and by qPCR detection of Geobacter > 2,600/g, with sulfate reducing bacteria <100/g. Thus, methane loss occurs within an active, iron-reducing zone, with Fe(III) as the only electron acceptor available in sufficient concentrations to account for methane disappearance. The oxidation of methane under anaerobic conditions in the hydrocarbon plume competes with benzene and other contaminants for Fe(III) on the sediments. Mass balance considerations suggest that this might explain in an additional 30 meters of growth in the benzene plume between 1995 and 2007. In general, these results show that large entrapped quantities of crude oil or other petroleum fuels create a long-term source of methane that degrades both aerobically and anaerobically. The oxidation of this methane under both aerobic and anaerobic conditions competes with hydrocarbon contaminants for limited electron acceptors in the subsurface.

  12. Overexpression of the Brassica napus BnLAS gene in Arabidopsis affects plant development and increases drought tolerance.

    PubMed

    Yang, Minggui; Yang, Qingyong; Fu, Tingdong; Zhou, Yongming

    2011-03-01

    The GRAS proteins are a family of transcription regulators found in plants and play diverse roles in plant growth and development. To study the biological roles of GRAS family genes in Brassica napus, an Arabidopsis LAS homologous gene, BnLAS and its two homologs were cloned from B. napus and its two progenitor species, Brassica rapa and Brassica oleracea. Relatively high levels of BnLAS were observed in roots, shoot tips, lateral meristems and flower organs based on the analysis of the transcripts by quantitative RT-PCR and promoter-reporter assays. Constitutive overexpression of BnLAS in Arabidopsis resulted in inhibition of growth, and delays in leaf senescence and flowering time. A large portion of transgenic lines had darker leaf color and higher chlorophyll content than in wild type plants. Interestingly, water lose rates in transgenic leaves were reduced, and transgenic plants exhibited enhanced drought tolerance and increased recovery after exposed to dehydration treatment. The stomatal density on leaves of the transgenic plants increased significantly due to the smaller cell size. However, the stomatal aperture on the leaves of the transgenic plants reduced significantly compared with wild type plants. More epidermal wax deposition on transgenic leaves was observed. Furthermore, several genes involved in wax synthesis and regulation, including CER1, CER2, KCS1 and KCS2, were upregulated in the transgenic plants. Our results indicate a potential to utilize BnLAS in the improvement of drought tolerance in plants.

  13. The study of ozone variations in the Las Vegas metropolitan area using remote sensing information and ground observations

    USGS Publications Warehouse

    Xian, G.; Crane, M.

    2006-01-01

    Urban development in the Las Vegas Valley, Nevada, has grown rapidly in the past fifty years. Associated with this growth has been a change in landscape from natural cover types to developed urban land mixed with planned vegetation canopy throughout in the metropolitan area. Air quality in the Las Vegas Valley has been affected by increases in anthropogenic emissions and concentrations of carbon monoxide, ozone, and criteria pollutants of particular matter. Ozone concentration in the region is generally influenced by synoptic and mesoscale meteorological conditions, as well as regional transport of pollutants from the western side of Las Vegas. Local influences from ground-level nitrogen oxide emissions and vegetation canopy coverage also affect ozone concentration. Multi-year observational data collected by a network of local air monitoring stations in Clark County, Nevada, indicate that ozone maximums develop in May and June, while minimums exist primarily from November to February. Ozone concentrations are high on the west and northwest sides of the valley. A nighttime ozone reduction in the urban area characterizes the heterogeneous features of spatial distribution for average ozone levels in the Las Vegas urban area. The urban vegetation canopy has a locally positive effect by reducing ozone in urban areas. Decreased ozone levels associated with increased urban development density suggests that the highest ozone concentrations are associated with medium- to low-density urban development in Las Vegas.

  14. Shallow Shear Velocity and Seismic Microzonation of the Las Vegas Urban Basin

    NASA Astrophysics Data System (ADS)

    Rasmussen, T.; Smith, S. B.; Clark, M.; Lopez, C.; Loughner, C.; Park, H.; Scott, J. B.; Thelen, W.; Greschke, B.; Louie, J. N.

    2003-12-01

    In July 2003 we performed a seismic microzonation study of the Las Vegas basin along a 15 kilometer transect. Using 120 Reftek RT-125 "Texans" on loan from PASSCAL, we completed this transect in two days. 4.5-Hz geophones collected Rayleigh-wave data for dispersion analysis and velocity-profile modeling. Only passive urban seismic noise sources are needed for this refraction microtremor analysis; freeway and commuter traffic are used in this case. Using a geophone spacing of 20 meters, fifty 260-m array sections were analyzed to create a transect of 30-m shear velocity measurements 15 km long. The transect runs approximately parallel to Interstate 15 from Cheyenne Avenue at the north to Tropicana Avenue at the south, passing most of The Strip and downtown Las Vegas. We added a few refraction lines, with a sledgehammer source, to augment the microtremor dispersion data with P velocities. The lowest shear velocities observed in Las Vegas are in the NEHRP class D range, at 230 m/s, well above the NEHRP class E range. These lower velocities are found near Interstate 15 and Lake Mead Blvd. Velocities then rise smoothly southward to the middle of the NEHRP-C range (450-600 m/s) near Sahara Blvd. to the south. There appears to be a slight decline further south to Tropicana Blvd. Our results from only 3 km out of the 15-km-long transect have velocities near or below the NEHRP-C/D boundary at 350 m/s. This survey suggests a medium-scale study with a limited budget can be completed in a short time. The study is a crucial new step in the characterization of the effects of ground shaking due to a seismic source in the surrounding region. Similar studies have been completed in the Reno area basin and in the Los Angeles Basin. All of these studies suggest that shallow shear velocity does not correlate well with geologic map units. The range of velocities within one map unit is greater than the average difference between units.

  15. Sociohydrology of an Arid City: Development of a Coupled Model of Water Management in Las Vegas

    NASA Astrophysics Data System (ADS)

    Garcia, M. E.; Islam, S.; Portney, K. E.

    2014-12-01

    Rapidly growing cities in arid regions present a significant water management challenge. Key to tackling this challenge is understanding how and why some cities transition to more sustainable water management; acknowledging that urban water resources decisions are both responding to and precipitating hydrologic change, this question is best tackled through a sociohydrology approach. While coupling of natural and societal systems is in it's infancy in the field of hydrology, there is a strong tradition of studying coupled systems in the field of Socio-Ecological Systems. We build on Ostrom's Socio-Ecological Systems framework to develop a system dynamics model of water management for the Las Vegas metropolitan area using Vensim. A key objective our proposed modeling framework is to illuminate the dynamic interactions of the sociohydrologic system components and enable testing of various assumptions and strategies. The model of Las Vegas water management consists of five sub-modules: water supply, water demand, finances, public perception and policy making process. The development of the first three modules were based on clearly defined system structure. The public perception sub-module tracks the level public risk perception of a water supply shortage and represents the hypothesis that public risk perception is updated periodically when shortage events are experienced. The policy making process module uses an algorithm capturing the hypothesized decision making process to select policy actions (or in-action) from a set of feasible actions in response to the system states tracked by the model and observable to decision makers. The model was tested and parameterized using mix of quantitative data on water demands, supplies and costs and qualitative data from document analysis and interview data covering 1990 to 2010 period. Given that not only the parameters but also the structure of the public perception and the policy making process sub-systems is contested, a

  16. Geodetic Constraints on Fault Slip Rates and Seismic Hazard in the Greater Las Vegas Area

    NASA Astrophysics Data System (ADS)

    Hammond, W. C.; Kreemer, C.; Blewitt, G.; Broermann, J.; Bennett, R. A.

    2014-12-01

    We address fundamental questions about how contemporary tectonic deformation of the crust in the southern Great Basin occurs in the region around Las Vegas (LV) Nevada, western Arizona and eastern California. This area lies in the intersection of the eastern Walker Lane Belt, southern Great Basin and western Colorado Plateau (CP), sharing features of transtensional and extensional deformation associated with Pacific/North America relative motion. We use GPS data collected from 48 stations of the MAGNET semi-continuous network and 77 stations from continuous networks including BARGEN and EarthScope Plate Boundary Observatory. MAGNET stations have been observed for a minimum of 7 years, while most continuous stations have longer records. From these data we estimate the velocity of crustal motion for all stations with respect to the stable North America reference frame NA12. To correct for transients from recent large earthquakes including the 1999 Hector Mine and 2010 El Mayor-Cucapah events we use models of co- and post-seismic deformation, subtracting the predicted motions from the time series before estimating interseismic stain rates. We find approximately 2 mm/yr of relative motion distributed over 200 km centered on Las Vegas, with a mean strain accumulation rate of 10 × 10-9 yr-1, with lower rates of predominantly extensional strain to the east and higher rates of predominantly shear deformation to the west. The mean strain rate is lower than that of the western Walker Lane but about twice that of eastern Nevada where e.g., the Wells, NV MW 6.0 earthquake occurred in 2008. From this new velocity field we generated a horizontal tensor strain rate map and a crustal block motion model to portray the transition of active strain from the CP into the Walker Lane. For faults in the Las Vegas Valley, including the Eglington Fault and Frenchman Mountain Fault, the observed velocity gradients and model results are consistent with normal slip rates of 0.2 mm/yr, which

  17. 20 years of mass balances on the Piloto glacier, Las Cuevas river basin, Mendoza, Argentina

    NASA Astrophysics Data System (ADS)

    Leiva, J. C.; Cabrera, G. A.; Lenzano, L. E.

    2007-10-01

    Climatic changes of the 20th century have altered the water cycle in the Andean basins of central Argentina. The most visible change is seen in the mountain glaciers, with loss of part of their mass due to decreasing thickness and a substantial recession in the last 100 years. This paper briefly describes the results of glacier mass balance research since 1979 in the Piloto Glacier at the Cajón del Rubio, in the headwaters of Las Cuevas River, presenting new results for the period 1997-2003. Very large interannual variability of net annual specific balance is evident, due largely to variations in winter snow accumulation, with a maximum net annual value of + 151 cm w.e. and a minimum value of - 230 cm w.e. Wet El Niño years are normally associated with positive net annual balances, while dry La Niña years generally result in negative balances. Within the 24-year period, 67% of the years show negative net annual specific balances, with a cumulative mass balance loss of - 10.50 m water equivalent (w.e.). Except for exceptions normally related to El Niño events, a general decreasing trend of winter snow accumulation is evident in the record, particularly after 1992, which has a strong effect in the overall negative mass balance values. The glacier contribution to Las Cuevas River runoff is analysed based on the Punta de Vacas River gauge station for a hypothetical year without snow precipitation (YWSP), when the snowmelt component is zero. Extremely dry years similar to a YWSP have occurred in 1968-1969, 1969-1970 and 1996-1997. The Punta de Vacas gauge station is located 62 km downstream from Piloto Glacier, and the basin contains 3.0% of uncovered glacier ice and 3.7% of debris-covered ice. The total glacier contribution to Las Cuevas River discharge is calculated as 82 ± 8% during extremely dry years. If glacier wastage continues at the present trend as observed during the last 2 decades, it will severely affect the water resources in the arid central Andes of

  18. A design for a new catalog manager and associated file management for the Land Analysis System (LAS)

    NASA Technical Reports Server (NTRS)

    Greenhagen, Cheryl

    1986-01-01

    Due to the larger number of different types of files used in an image processing system, a mechanism for file management beyond the bounds of typical operating systems is necessary. The Transportable Applications Executive (TAE) Catalog Manager was written to meet this need. Land Analysis System (LAS) users at the EROS Data Center (EDC) encountered some problems in using the TAE catalog manager, including catalog corruption, networking difficulties, and lack of a reliable tape storage and retrieval capability. These problems, coupled with the complexity of the TAE catalog manager, led to the decision to design a new file management system for LAS, tailored to the needs of the EDC user community. This design effort, which addressed catalog management, label services, associated data management, and enhancements to LAS applications, is described. The new file management design will provide many benefits including improved system integration, increased flexibility, enhanced reliability, enhanced portability, improved performance, and improved maintainability.

  19. 3D inversion of aeromagnetic Data on Las Tablas District, Panama

    NASA Astrophysics Data System (ADS)

    Batista-Rodríguez, José A.; Caballero, Alberto; Pérez-Flores, Marco A.; Almaguer-Carmenates, Yuri

    2017-03-01

    We present a 3D model of Las Tablas District, Panama, obtained from the 3D inversion of aeromagnetic data, and constrained with information from surface geology, water wells and topography. The 3D model suggests the location, boundary, shape and depths of the sedimentary basin where the Mensabé and Salados rivers hydrogeological sub-basin is located. The model shows the connections between tectonics and the sedimentary basin, suggesting the probable areas for aquifers, the relations between them, their zone of recharge and discharge, and the probable zone of pollution. The inferred faults in the model may be the main recharge and discharge conduits for the groundwater and anthropogenic pollution. The geological and geometric characteristics shown in the 3D model are fundamental data for further hydrogeological and geophysical studies such as the location for future drinking water wells.

  20. Neighborhood Reputation and Resident Sentiment in the Wake of the Las Vegas Foreclosure Crisis.

    PubMed

    Pais, Jeremy; Batson, Christie D; Monnat, Shannon M

    2014-09-01

    This study examines how two major components of a neighborhood's reputation-perceived disorder and collective efficacy-shape individuals' sentiments toward their neighborhoods during the foreclosure crisis triggered by the Great Recession. Of central interest are whether neighborhood reputations are durable in the face of a crisis (neighborhood resiliency hypothesis) or whether neighborhood reputations wane during times of duress (foreclosure crisis hypothesis). Geo-coded individual-level data from the Las Vegas Metropolitan Area Social Survey merged with data on census tract foreclosure rates are used to address this question. The results provide qualified support for both perspectives. In support of the neighborhood resiliency hypothesis, collective efficacy is positively associated with how residents feel about the quality of their neighborhoods, and this relationship is unaltered by foreclosure rates. In support of the foreclosure crisis hypothesis, foreclosure rates mediate the effects of neighborhood disorder on resident sentiment. The implications of these findings for community resiliency are discussed.

  1. The Proteus aircraft and NASA Dryden's T-34 in flight over Las Cruces, New Mexico.

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The unique Proteus aircraft served as a test bed for NASA-sponsored flight tests designed to validate collision-avoidance technologies proposed for uninhabited aircraft. The tests, flown over southern New Mexico in March, 2002, used the Proteus as a surrogate uninhabited aerial vehicle (UAV) while three other aircraft flew toward the Proteus from various angles on simulated collision courses. Radio-based 'detect, see and avoid' equipment on the Proteus successfully detected the other aircraft and relayed that information to a remote pilot on the ground at Las Cruces Airport. The pilot then transmitted commands to the Proteus to maneuver it away from the potential collisions. The flight demonstration, sponsored by NASA Dryden Flight Research Center, New Mexico State University, Scaled Composites, the U.S. Navy and Modern Technology Solutions, Inc., were intended to demonstrate that UAVs can be flown safely and compatibly in the same skies as piloted aircraft.

  2. The Palomar-Las Campanas Observatory-NOAO (PLCON) Open Cluster Survey

    NASA Astrophysics Data System (ADS)

    Phelps, R. L.; Tollefson, J.; Reafsnyder, S.; Frinchaboy, P.; Craig, Aidan; Postlethwaite, J.; Marshall, T.

    2000-12-01

    The Palomar-Las Campanas Observatory-NOAO (PLCON) Open Cluster Survey is a long-term survey intended to provide CCD derived, VI color-magnitude diagrams for the majority of the Milky Way's open clusters, most of which have been poorly studied in the past, or never studied at all. From these data, systematic estimates of cluster reddenings, distances and ages can be derived using a limited number of telescopes, CCDs and filter sets. These data will be useful for systematic studies of Galactic structure in the disk, the properties of unique/interesting stars within clusters, stellar evolution theory, and a host of other timely astrophysical questions. This paper will report on recent results from the Survey. This work is supported, in part, by grants from the National Science Foundation and the California State University, Sacramento Research and Creative Activity Awards Program.

  3. Prevalence of ectoparasitic arthropods on wild animals and cattle in the Las Merindades area (Burgos, Spain)

    PubMed Central

    Domínguez-Peñafiel, G.; Giménez-Pardo, C.; Gegúndez, M.I.; Lledó, L.

    2011-01-01

    This paper reports the prevalence of ectoparasitic arthropods in sampled groups of wild (n = 128; 16 species) and domestic (n = 69; 3 species) animals in the Las Merindades area of the Province of Burgos, Spain. The study revealed that wild animals were more infested and with a wider variety of ectoparasites than domestic animals. The parasitic prevalence was 67% for wild animals and 48% for livestock. In this way, 39% of animals were infected by ticks. Ixodes ricinus and Ixodes hexagonus were the most prevalent species whereas Dermacentor reticulatus showed affinity for the fox and wolf. The overall prevalence of parasitisation by fleas was 27%. Ctenophthalmus spp. showed the wider range host in wild animals, while Pulex irritans was the most frequent specie found. The parasitic prevalences by lice (Trichodectes melis, Trichodectes canis and Trichodectes mustelae) and by mite (Neotrombicula spp., Laelaps agilis and Sarcoptes scabiei) were 4% and 12%, respectively. In both cases only wild animals were found parasited. PMID:21894267

  4. Neighborhood Reputation and Resident Sentiment in the Wake of the Las Vegas Foreclosure Crisis

    PubMed Central

    Pais, Jeremy; Batson, Christie D.; Monnat, Shannon M.

    2014-01-01

    This study examines how two major components of a neighborhood’s reputation—perceived disorder and collective efficacy—shape individuals’ sentiments toward their neighborhoods during the foreclosure crisis triggered by the Great Recession. Of central interest are whether neighborhood reputations are durable in the face of a crisis (neighborhood resiliency hypothesis) or whether neighborhood reputations wane during times of duress (foreclosure crisis hypothesis). Geo-coded individual-level data from the Las Vegas Metropolitan Area Social Survey merged with data on census tract foreclosure rates are used to address this question. The results provide qualified support for both perspectives. In support of the neighborhood resiliency hypothesis, collective efficacy is positively associated with how residents feel about the quality of their neighborhoods, and this relationship is unaltered by foreclosure rates. In support of the foreclosure crisis hypothesis, foreclosure rates mediate the effects of neighborhood disorder on resident sentiment. The implications of these findings for community resiliency are discussed. PMID:25678735

  5. Late Neandertals in Southeastern Iberia: Sima de las Palomas del Cabezo Gordo, Murcia, Spain

    PubMed Central

    Walker, Michael J.; Gibert, Josep; López, Mariano V.; Lombardi, A. Vincent; Pérez-Pérez, Alejandro; Zapata, Josefina; Ortega, Jon; Higham, Thomas; Pike, Alistair; Schwenninger, Jean-Luc; Zilhão, João; Trinkaus, Erik

    2008-01-01

    Middle Paleolithic fossil human remains from the Sima de las Palomas in southeastern Iberia (dated to ≤43,000–40,000 calendar years before present) present a suite of derived Neandertal and/or retained ancestral morphological features in the mandibular symphysis, mandibular ramus, dental occlusal morphology, and distal hand phalanx. These traits are combined with variation in the mandibular corpus, discrete dental morphology, tooth root lengths, and anterior dental size that indicate a frequency difference with earlier Iberian and more northern European Neandertals. The Palomas Neandertals therefore confirm the late presence of Neandertals associated with the Iberian persistence of the Middle Paleolithic, but suggest microevolutionary processes and/or population contact with contemporaneous modern humans to the north. PMID:19074275

  6. Neandertal postcranial remains from the Sima de las Palomas del Cabezo Gordo, Murcia, southeastern Spain.

    PubMed

    Walker, Michael J; Ortega, Jon; López, Mariano V; Parmová, Klára; Trinkaus, Erik

    2011-04-01

    The Sima de las Palomas, southeastern Spain, has yielded a series of Neandertal postcranial remains, including immature and mature isolated elements and the fragmentary partial skeleton of a young adult (Palomas 92). The remains largely conform to the general late archaic/Neandertal morphological pattern in terms of humeral diaphyseal shape, pectoralis major tuberosity size and pillar thickness, ulnar coronoid process height, manual middle phalangeal epiphyseal breadth, manual distal phalangeal tuberosity shape and breadth, femoral diaphyseal shape, and probably body proportions. Palomas 92 contrasts with the Neandertals in having variably gracile hand remains, a more sellar trapezial metacarpal 1 facet, more anteroposteriorly expanded mid-proximal femoral diaphysis, and less robust pedal proximal phalanges. The Palomas Neandertals contrast with more northern European Neandertals particularly in various reflections of overall body size.

  7. Late neandertals in southeastern Iberia: Sima de las Palomas del Cabezo Gordo, Murcia, Spain.

    PubMed

    Walker, Michael J; Gibert, Josep; López, Mariano V; Lombardi, A Vincent; Pérez-Pérez, Alejandro; Zapata, Josefina; Ortega, Jon; Higham, Thomas; Pike, Alistair; Schwenninger, Jean-Luc; Zilhão, João; Trinkaus, Erik

    2008-12-30

    Middle Paleolithic fossil human remains from the Sima de las Palomas in southeastern Iberia (dated to

  8. Spatial distribution and contamination assessment of heavy metals in urban topsoils from Las Tunas City, Cuba.

    PubMed

    Díaz Rizo, O; Fonticiella Morell, D; Arado López, J O; Borrell Muñoz, J L; D'Alessandro Rodríguez, K; López Pino, N

    2013-07-01

    Concentrations of Cr, Co, Ni, Cu, Zn, Pb and Fe in the topsoils (0-10 cm) from Las Tunas city were measured by X-ray fluorescence analysis. The mean Cr, Co, Ni, Cu, Zn and Pb contents in the urban topsoil samples (97 ± 30, 14 ± 2, 35 ± 36, 94 ± 26, 199 ± 87 and 42 ± 29 mg kg⁻¹ dry weight, respectively) were compared with mean concentrations for other cities around the world with similar population. Cr content in school grounds, parks and residential areas exceed in 20 % the average Cr background level. Highest content for Ni was determined in residential areas, for Zn in market gardens soils and as for Pb, the highest topsoil-background content ratios were observed for market gardens (2.7) and residential areas (2.3). Spatial distribution maps indicated the same behaviour for Cr-Co-Ni and Pb-Zn, respectively, whereas the spatial distribution of Cu differs from other heavy metals. On the other hand, the metal-to-iron normalisation, using (10-20 cm) bottom soil contents as background, showed that topsoils in Las Tunas city are severely enriched with lead and not enriched with the rest of the determined metals. The average values of integrated pollution index (IPI) indicated that soils are moderately contaminated by heavy metals (1.17 ≤ IPI(ave) ≤ 1.39), but enrichment index values shows that metal concentrations on the studied locations are not above the permissible levels for urban agriculture.

  9. Fishery of the Green Jack Caranx caballus (Osteichytes: Carangidae) in Las Perlas Archipelago, Pacific Panama.

    PubMed

    Mair, James M; Cipriani, Roberto; Guzman, Hector M; Usan, David

    2012-09-01

    Green Jacks, Caranx caballus, are distributed along the Eastern Pacific coast. In Panama, C. caballus was heavily fished around Las Perlas Archipelago to sustain local markets until 2007, when the archipelago was declared a marine protected area. This first study in Panama, analyzed a sample of 4 990 individuals from Las Perlas, obtained monthly from June 2005 to June 2006, from landings at the central fish market. Average total length was 36.1 +/- 6.4cm and optimum length 38.9cm. Approximately 68% of fish lengths were within +/-10% of the optimal length but only six (15%) were considered mega-spawners. The von Bertalanffy parameters describe a long-lived and fast growing species, while mortality rates revealed that C. caballus is under high fishing pressure. Standard length at which half of the population is mature was 38.8cm, and the size at which individuals matured massively, 33cm. Only 10-13% of the fish were immature. C. caballus reproduces two to three times per year, with peaks in December, April, and probably September, and recruits to the population at least twice per year. Catch per unit effort (CPUE) was best predicted by minimum annual values of the Multivariate ENSO/LNSO Index (MEI) (R2=0.54). Results show that C. caballus in Pacific Panama is overfished. We recommend the raising of the minimum capture/landing size of this species in order to increase the proportion of mega-spawners in the population and guarantee the sustainability of this resource.

  10. Regiones de formación de estrellas masivas en las Nubes de Magallanes

    NASA Astrophysics Data System (ADS)

    Barbá, R.; Maíz Apellániz, J.; Rubio, M.; Walborn, N.

    Las Nubes de Magallanes son un laboratorio formidable para el estudio de regiones de formación estelar. A diferencia de lo que sucede en el plano galáctico, ambas galaxias contienen poco polvo que nos afecte la visión directa de dichas regiones. Por otra parte, la menor metalicidad de las Nubes, nos permiten hacer un estudio comparativo de la formación estelar en ambientes de baja metalicidad. El presente trabajo da una revisión de los progresos notables que hemos alcanzado en el conocimiento del contenido estelar de algunas regiones de formación de estrellas masivas en ambas Nubes, en base a la utilización de imágenes del Telescopio Espacial Hubble, Gemini Sur, y Very Large Telescope, entre otros. En especial, nos concentramos en 30 Doradus y N11 en la Nube Mayor, y en NGC 346 en la Nube Menor. Nuevas imágenes de N11 obtenidas en los últimos meses con la Advanced Camera for Surveys del Hubble (óptico), y con Flamingos en Gemini Sur (infrarrojo), nos han permitido descubrir un nuevo `jet' con origen en una fuente infrarroja sumergida en un pilar polvoriento similar al objeto Herbig-Haro de M20 en nuestra galaxia. Este `jet' (junto a otros tres que hemos descubierto en 30 Doradus), es el cuarto ejemplo confirmado de `jet' asociado a una protoestrella fuera de nuestra galaxia. Además, presentamos el descubrimiento del primer objeto estelar joven masivo de la Nube Menor confirmado espectroscópicamente.

  11. Precisión de las velocidades radiales obtenidas con el REOSC

    NASA Astrophysics Data System (ADS)

    González, J. F.; Lapasset, E.

    Complementando una línea de trabajo iniciada con anterioridad discutimos la estabilidad del espectrógrafo REOSC de CASLEO en DC para la medición de velocidades radiales en base al análisis de observaciones realizadas en enero y abril de 1997. En esas oportunidades obtuvimos 26 espectros de estrellas patrones y 27 espectros de 3 estrellas usadas como estrellas de referencia en nuestro programa de cúmulos abiertos. Además tomamos 26 espectros de crepúsculo con el telescopio en posiciones cubriendo el rango H=-4,+4 y δ =-90,+30. Mediante correlaciones cruzadas derivamos la velocidad de 19 órdenes en cada uno de estos espectros. En base a un análisis estadístico de los datos obtenidos discutimos la contribución de los distintos factores que afectan a la dispersión de lectura observada. En particular, la flexión del instrumento no introduciría errores significativos cuando se observa con masas de aire menores que 2.0. La dispersión de los valores de velocidad medidos para espectros de alta relación S/N de una misma estrella resultó del orden de 0.5 km/s. La comparación con los valores de velocidad publicados por distintos autores para las estrellas patrones no permite distinguir ninguna diferencia sistemática apreciable de las velocidades de CASLEO, siendo la media cuadrática de los residuos del orden de 1.0 km/s.

  12. Stratospheric contribution to surface ozone in the desert Southwest during the 2013 Las Vegas Ozone Study

    NASA Astrophysics Data System (ADS)

    Langford, A. O.; Senff, C. J.; Alvarez, R. J. _II, II; Brioude, J. F.; Cooper, O. R.; Holloway, J. S.; Lin, M.; Marchbanks, R.; Pierce, R. B.; Reddy, P. J.; Sandberg, S.; Weickmann, A. M.; Williams, E. J.; Gustin, M. S.; Iraci, L. T.; Leblanc, T.; Yates, E. L.

    2014-12-01

    The 2013 Las Vegas Ozone Study (LVOS) was designed to investigate the potential impact of stratosphere-troposphere transport (STT) and long-range transport of pollution from Asia on surface O3 concentrations in Clark County, NV. This measurement campaign, which took place in May and June of 2013, was conducted at Angel Peak, NV, a high elevation site about 2.8 km above mean sea level and 45 km west of Las Vegas. The study was organized around the NOAA ESRL truck-based TOPAZ scanning ozone lidar with collocated in situ sampling of O3, CO, and meteorological parameters. These measurements were supported by the NOAA/NESDIS real time modelling system (RAQMS), FLEXPART particle dispersion model, and the NOAA GFDL AM3 model. In this talk, I will describe one of several STT events that occurred during the LVOS campaign. This intrusion, which was profiled by TOPAZ on the night of May 24-25, was also sampled by the NASA Alpha Jet, the Table Mountain ozone lidar, and by an ozonesonde flying above southern California. This event also led to significant ozone increases at surface monitors operated by Clark County, the California Air Resources Board, the U.S. National Park Service, and the Nevada Rural Ozone Initiative (NRVOI), and resulted in exceedances of the 2008 75 ppbv O3 NAAQS both in Clark County and in surrounding areas of Nevada and southern California. The potential implications of this and similar events for air quality compliance in the western U.S. will be discussed.

  13. Characterization of stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, 1998-99

    USGS Publications Warehouse

    Rodriguez, Jose M.

    2000-01-01

    Stormwater discharges from Las Flores Industrial Park, Rio Grande, Puerto Rico, were characterized from June 1998 to July 1999 by measuring the flow rate at two outfalls, delineating the drainage areas for each outfall, and calculating the volume of the stormwater discharges. Stormwater-discharge samples were collected and analyzed to determine the quality of the discharges. Constituent loads and loads per area were estimated for each drainage area. The studied drainage subareas covered approximately 46 percent of the total area of the Las Flores Industrial Park. Industrial groups represented in the study areas include manufacturers of textile, electronics, paper, fabricated metal, plastic, and chemical products. The concentrations of oil and grease (1 to 6 milligrams per liter), biochemical oxygen demand (4.7 to 16 milligrams per liter), total organic carbon (5.8 to 36 milligrams per liter), total suspended solids (28 to 100 milligrams per liter), and total phosphorous (0.11 to 0.78 milligrams per liter) from all the samples collected were less than the U.S. Environmental Protection Agency stormwater benchmark concentrations. Concentrations of chemical oxygen demand (15.8 to 157 milligrams per liter) and nitrate and nitrite (0.06 to 1.75 milligrams per liter) exceeded benchmark concentrations at one of the studied drainage areas. Total Kjeldahl nitrogen concentrations (1.00 to 3.20 milligrams per liter) exceeded the benchmark concentrations at the two studied drainage areas. Maximum concentrations for oil and grease, biochemical oxygen demand, chemical oxygen demand, total organic carbon, total Kjeldahl nitrogen, nitrate plus nitrite, and total phosphorous were detected in an area where electronics, plastics, and chemical products are currently manufactured. The maximum concentration of total suspended solids was detected at an area where textile, paper, plastic, chemical, and fabricated metal products are manufactured.

  14. Molecular insight into the activity of LasR protein from Pseudomonas aeruginosa in the regulation of virulence gene expression by this organism.

    PubMed

    Chowdhury, Nilkanta; Bagchi, Angshuman

    2016-04-10

    Pseudomonas aeruginosa is an opportunistic human pathogen. This organism attacks human patients suffering from diseases like AIDS, cancer, cystic fibrosis, etc. One of the important virulent factors produced by this organism is Hydrogen Cyanide. This is expressed from the genes encoded by the hcnABC operon. The expressions of the genes encoded by hcnABC operon are mediated mainly by the interactions of LasR protein with the corresponding promoter region of the hcnABC operon. The LasR protein acts as a dimer and binds to the promoter DNA with the help of an autoinducer ligand. However, till date the detailed molecular mechanism of how the LasR protein interacts with the promoter DNA is not clearly known. Therefore, in this work, an attempt has been made to analyze the mode of interactions of the LasR protein with the promoter DNA region of the hcnABC operon. We analyzed the three dimensional structure of the LasR protein from Pseudomonas aeruginosa and docked the protein with the autoinducer ligand. We then docked the ligand-bound-LasR-protein as well the LasR-protein-without-the-autoinducer-ligand on to the promoter DNA region of hcnABC operon. We analyzed the details of the interaction profiles of LasR protein with the autoinducer ligand. We also deciphered the details of the LasR promoter-DNA interactions. We compared the modes of DNA bindings by the LasR protein in presence and absence of the autoinducer ligand and tried to analyze the molecular details of the binding of LasR protein with the promoter DNA region of hcnABC operon during hcnABC gene expression. This study may therefore pave the pathway for future experiments to determine the relative effects of the amino acid residues of LasR protein in DNA binding during the transcription of hcnABC operon.

  15. Unraveling the contributions of hydrogen-bonding interactions to the activity of native and non-native ligands in the quorum-sensing receptor LasR

    PubMed Central

    Gerdt, Joseph P.; McInnis, Christine E.; Schell, Trevor L.; Blackwell, Helen E.

    2014-01-01

    Quorum sensing (QS) via the synthesis and detection of N-acyl L-homoserine lactone (AHL) signals regulates important pathogenic and mutualistic phenotypes in many bacteria. Over the past two decades, the development of non-native molecules that modulate this cell-cell signaling process has become an active area of research. The majority of these compounds were designed for block binding of the native AHL signal to its cognate LuxR-type receptor, and much effort has focused on LasR in the opportunistic pathogen Pseudomonas aeruginosa. Despite a small set of reported LasR structural data, it remains unclear which polar interactions are most important for either (i) activation of the LasR receptor by its native AHL signal, N-(3-oxo)-dodecanoyl L-homoserine lactone (OdDHL), or (ii) activation or inhibition of LasR by related AHL analogs. Herein, we report our investigations into the activity of OdDHL and five synthetic analogs in wild-type LasR and in nine LasR mutants with modifications to key polar residues in their ligand binding sites. Our results allowed us to rank, for the first time, the relative importance of each LasR:OdDHL hydrogen bond for LasR activation and provide strong evidence for the five synthetic ligands binding LasR in a very similar orientation as OdDHL. By delineating the specific molecular interactions that are important for LasR modulation by AHLs, these findings should aid in the design of new synthetic modulators of LasR (and homologous LuxR-type receptors) with improved potencies and selectivities. PMID:25474181

  16. Can a Spanish Science Education Journal Become International? The Case of "Enseñanza De Las Ciencias"

    ERIC Educational Resources Information Center

    Espinet, Mariona; Izquierdo, Mercè; Garcia-Pujol, Clara

    2015-01-01

    In this paper we discuss the case of the science education research journal "Enseñanza de las Ciencias" ("EC") around the issue of its internationalization and the consequences this process has had and is still having on the use and preservation of different languages and more specifically the Castilian (Spanish) language. We…

  17. Seasonal and diurnal analysis of NO2 concentrations from a long-duration study conducted in Las Vegas, Nevada

    EPA Science Inventory

    A study, conducted in Las Vegas, NV from mid-December 2008 to mid-December 2009 along an interstate highway, collected continuous and integrated ambient air quality samples for a wide variety of species including NO2 and NOX. Previous near-road studies have been short duration, ...

  18. Ambient air monitoring during the 2011 Las Conchas wildland fire near Los Alamos, U.S.A.

    SciTech Connect

    Green, Andrew A.; Schlemann, Shea A.; Young, Daniel L.

    2012-08-31

    Air monitoring data collected during the Las Conchas fire near the Los Alamos National Laboratory during 2011 are presented. Data included are for selected radionuclides and selected metals found in particulate matter. None of these analytes were seen at levels which exceeded any state or federal standards.

  19. Mechanistic analysis of a synthetic inhibitor of the Pseudomonas aeruginosa LasI quorum-sensing signal synthase

    PubMed Central

    Lidor, O.; Al-Quntar, A.; Pesci, E. C.; Steinberg, D.

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen responsible for many human infections. LasI is an acyl-homoserine lactone synthase that produces a quorum-sensing (QS) signal that positively regulates numerous P. aeruginosa virulence determinants. The inhibition of the LasI protein is therefore an attractive drug target. In this study, a novel in silico to in vitro complementation was applied to screen thiazolidinedione-type compounds for their ability to inhibit biofilm formation at concentrations not affecting bacterial growth. The compound (z)-5-octylidenethiazolidine-2, 4-dione (TZD-C8) was a strong inhibitor of biofilm formation and chosen for further study. Structural exploration of in silico docking predicted that the compound had high affinity for the LasI activity pocket. The TZD-C8 compound was also predicted to create hydrogen bonds with residues Arg30 and Ile107. Site-directed mutagenesis (SDM) of these two sites demonstrated that TZD-C8 inhibition was abolished in the lasI double mutant PAO-R30D, I107S. In addition, in vitro swarming motility and quorum sensing signal production were affected by TZD-C 8, confirming this compound alters the cell to cell signalling circuitry. Overall, this novel inhibitor of P. aeruginosa quorum sensing shows great promise and validates our mechanistic approach to discovering inhibitors of LuxI-type acyl-homoserine lactone synthases. PMID:26593271

  20. 77 FR 28569 - Reorganization and Expansion of Foreign-Trade Zone 89 Under Alternative Site Framework, Las Vegas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-15

    ... Framework, Las Vegas, NV Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as..., the Board adopted the alternative site framework (ASF) (74 FR 1170, 01/12/2009; correction 74 FR 3987... application to reorganize and expand FTZ 89 under the alternative site framework is approved, subject to...

  1. Preliminary information on ambient concentrations measured at the Las Vegas National Near-Road MSAT study site

    EPA Science Inventory

    This paper provides preliminary information on the trends in ambient concentrations observed near a heavily traveled highway in Las Vegas, Nevada. As part of a joint effort by the U.S. Environmental Protection Agency (EPA) and Federal Highway Administration, an air monitoring pro...

  2. What Happens in Vegas Does "Not" Stay in Vegas: Youth Leadership in the Immigrant Rights Movement in Las Vegas, 2006

    ERIC Educational Resources Information Center

    Revilla, Anita Tijerina

    2012-01-01

    Students calling themselves the Las Vegas Activist Crew shut down the city's famed Strip on May 1, 2006, with an immigrant rights protest that was one of the largest demonstrations in Nevada's history. This research analyzes the ways that students engage in activism to improve their own social conditions and those of their communities. The…

  3. Bartolome de Las Casas; Protector of the Indians. The Tinker Pamphlet Series for the Teaching of Mexican American Heritage.

    ERIC Educational Resources Information Center

    Miller, Hubert J.

    Bartolome de las Casas devoted himself completely to crusading for the rights of the Indians. Although he was never a missionary among Indians, he began projects such as the Indians' conversion in the Land of War in Guatemala, which later became the task of his Dominican colleagues. However, his true importance lay in his role as the Indians'…

  4. El origen de las galaxias en modelos jerárquicos de formación de la estructura

    NASA Astrophysics Data System (ADS)

    Navarro, J. F.

    En esta charla presentaré una revisión de los modelos corrientes de formación de galaxias. En particular, haré énfasis en el origen de la gran variedad de morfologías galácticas y de las correlaciones entre las propiedades estructurales de discos y esferoides, todo dentro del contexto cosmológico jerárquico provisto por teorías como la de materia oscura fría. En este tipo de teorías las correlaciones observadas entre la luminosidad, velocidad de rotación, momento angular, y tamaño de galaxias son el resultado de la falta de escalas naturales en el proceso de formación de los halos de materia oscura que dichas galaxias habitan. Simulaciones numéricas que incorporan efectos gravitacionales, hidrodinámicos y de formación estelar ilustran estas ideas y demuestran las dificultades que aquejan a modelos donde tanto discos como esferoides son el resultado final de una secuencia de fusiones de sistemas protogalácticos.

  5. Female Adolescent Subjectivities in Las Vegas: Poststructural Thoughts on the Intersections of Gender, Sexuality, Consumer Logic and Curriculum

    ERIC Educational Resources Information Center

    Dentith, Audrey M.

    2004-01-01

    In this article, data collected from an ethnographic study of adolescent girls growing up in the city of Las Vegas in the US is used to further our understanding of the role of mediated sex and consumer culture and in relationship to emerging adolescent female identities. Girls in this study articulated a clear sense of their abilities to make…

  6. Growth and production of Donax striatus (Bivalvia: Donacidae) from Las Balsas beach, Gibara, Cuba.

    PubMed

    Ocaña, Frank A

    2015-09-01

    Clams of the genus Donax are worldwide the dominating group of the invertebrate community on sandy beaches. They are primary consumers that provide a significant abundance and biomass to the ecosystem. In the Caribbean, Donax striatus has an important role for nature and human, nonetheless studies on the population dynamics of this beach clam are scarce and no information exists on secondary production of this species. Growth parameters and secondary production of D. striatus were estimated from February 2008 to November 2009 at Las Balsas beach, Northeastern Cuba, in order to provide basic information for management purposes. In each month 45 samples were taken by means of a PVC corer of 0.025 m2 area and sieved with a 1 mm mesh. Animals were measured and weighted with and without shell. A total of 5 471 specimens were collected during the sampling period. Shell length ranged from 2.7-33.3 mm. Growth parameters estimated from length frequency data were L∞ = 36.1 mm, K= 0.8/yr and t0= 0.2/yr. The growth performance resulted in values of Φ'= 3.02. Life span was 2.4 yrs and mortality rate was 3.07 /yr. In 2008, mean abundance of D. striatus ranged between 17.1 - 770.7 ind./m2. In 2009 the lowest mean abundance was 34.4 and the highest was 892.5 ind./m2. During 2009 biomass and production was more than twice higher in comparison with 2008. Individual production showed highest values in the 24 mm shell size (3.74 g/m2.yr) and 25 mm (0.71 g/m2.yr), considering mass with shell and without shell, respectively. During 2009 abundance of individuals with 15 mm shell length or more increased resulting in higher biomass and production, compared to 2008. Using the conversion factor of wet mass to ash free dry mass (AFDM), annual production ranged between 2.87-6.11 g AFDM/m2.yr, resulting in a turnover rate (P/B) between 5.11 and 3.47 in 2008 and 2009, respectively. The rapid growth and high turnover rate of D. striatus suggest a rapid recovery of the population. These

  7. Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Virgin River, Nevada

    USGS Publications Warehouse

    Laney, R.L.; Bales, J.T.

    1996-01-01

    This study is the last of a series of eight geohydrologic reconnaissance studies that were done in the Lake Mead National Recreation Area. The studies were done to evaluate the water resources in the recreation area and to identify areas having potential for the development of water supplies that would be adequate for marinas and campgrounds. The study area includes about 250 square miles north of Lake Mead from Las Vegas Wash to the Virgin River (Overton Arm), Nevada. Volcanic rocks, consolidated sedimentary rocks, and unconsolidated to semiconsolidated sedimentary rocks underlie the area. Surface-water sources include the Colorado River, Virgin River, Muddy River, and Las Vegas Wash. Elsewhere in the area, streamflow is meager and extremely variable. Ground water originates from four sources: (1) subsurface flow in local basins, (2) infiltration of water from Lake Mead into permeable rocks near the lake, (3) subsurface flow in valleys of perennial streams, and (4) subsurface flow in consolidated rocks of the Muddy Mountains. The quantity of water from Lake Mead that has saturated rocks adjacent to the lake probably is greater than the quantity of ground water from all the Other sources. Rocks saturated by water from the lake probably extend less than 0.5 mileinland from the lake shore. The quality of virtually all the ground water in the area is not acceptable for drinking purposes. The most favorable areas for obtaining ground water are those underlain by the coarse-grained deposits of the older alluvium and the younger alluvium adjacent to Lake Mead. The least favorable areas are those underlain by the mudstone facies of the Muddy Creek Formation and fine-grained rocks of the Horse Spring Formation. Four areas identified as having potential for ground-water development are (1) near Overton Beach, (2) west of Callville Bay, (3) near Middle Point, and (4) in the lower Moapa Valley. Usable quantities of water probably can be obtained at these sites, but the

  8. Evaluating Water Supply and Water Quality Management Options for Las Vegas Valley

    NASA Astrophysics Data System (ADS)

    Ahmad, S.

    2007-05-01

    The ever increasing population in Las Vegas is generating huge demand for water supply on one hand and need for infrastructure to collect and treat the wastewater on the other hand. Current plans to address water demand include importing water from Muddy and Virgin Rivers and northern counties, desalination of seawater with trade- payoff in California, water banking in Arizona and California, and more intense water conservation efforts in the Las Vegas Valley (LVV). Water and wastewater in the LVV are intrinsically related because treated wastewater effluent is returned back to Lake Mead, the drinking water source for the Valley, to get a return credit thereby augmenting Nevada's water allocation from the Colorado River. The return of treated wastewater however, is a major contributor of nutrients and other yet unregulated pollutants to Lake Mead. Parameters that influence the quantity of water include growth of permanent and transient population (i.e., tourists), indoor and outdoor water use, wastewater generation, wastewater reuse, water conservation, and return flow credits. The water quality of Lake Mead and the Colorado River is affected by the level of treatment of wastewater, urban runoff, groundwater seepage, and a few industrial inputs. We developed an integrated simulation model, using system dynamics modeling approach, to account for both water quantity and quality in the LVV. The model captures the interrelationships among many variables that influence both, water quantity and water quality. The model provides a valuable tool for understanding past, present and future pathways of water and its constituents in the LVV. The model is calibrated and validated using the available data on water quantity (flows at water and wastewater treatment facilities and return water credit flow rates) and water quality parameters (TDS and phosphorus concentrations). We used the model to explore important questions: a)What would be the effect of the water transported from

  9. Human-health pharmaceutical compounds in Lake Mead, Nevada and Arizona, and Las Vegas Wash, Nevada, October 2000-August 2001

    USGS Publications Warehouse

    Boyd, Robert A.; Furlong, Edward T.

    2002-01-01

    The U.S. Geological Survey and the National Park Service conducted a reconnaissance study to investigate the occurrence of selected human-health pharmaceutical compounds in water samples collected from Lake Mead on the Colorado River and Las Vegas Wash, a waterway used to transport treated wastewater from the Las Vegas metropolitan area to Lake Mead. Current research indicates many of these compounds can bioaccumulate and may adversely affect aquatic organisms by disrupting physiological processes, impairing reproductive functions, increasing cancer rates, contributing to the development of antibiotic-resistant strains of bacteria, and acting in undesirable ways when mixed with other substances. These compounds may be present in effluent because a high percentage of prescription and non-prescription drugs used for human-health purposes are excreted from the body as a mixture of parent compounds and degraded metabolite compounds; also, they can be released to the environment when unused products are discarded by way of toilets, sinks, and trash in landfills. Thirteen of 33 targeted compounds were detected in at least one water sample collected between October 2000 and August 2001. All concentrations were less than or equal to 0.20 micrograms per liter. The most frequently detected compounds in samples from Las Vegas Wash were caffeine, carbamazepine (used to treat epilepsy), cotinine (a metabolite of nicotine), and dehydronifedipine (a metabolite of the antianginal Procardia). Less frequently detected compounds in samples collected from Las Vegas Wash were antibiotics (clarithromycin, erythromycin, sulfamethoxazole, and trimethoprim), acetaminophen (an analgesic and anti-inflammatory), cimetidine (used to treat ulcers), codeine (a narcotic and analgesic), diltiazem (an antihypertensive), and 1,7-dimethylxanthine (a metabolite of caffeine). Fewer compounds were detected in samples collected from Lake Mead than from Las Vegas Wash. Caffeine was detected in all samples

  10. Revisión de tecnología y riesgos: refinerías de petróleo - Hoja informativa para las comunidades

    EPA Pesticide Factsheets

    La Agencia de Protección Ambiental (EPA, por sus siglas en inglés) emitió un reglamento final que mejorará significativamente la calidad del aire en los vecindarios cercanos a las refinerías de petróleo mediante un control más exhaustivo de las emisiones a

  11. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  12. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  13. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  14. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  15. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  16. Posible culto al sol en los grabados rupestres de Las Hurdes (Cáceres).

    NASA Astrophysics Data System (ADS)

    Sevillano, C.

    The author presents a set of rock engravings located in the region of Las Hurdes (Cäceres) a mountainous region to the west of the Central System of the Iberian Peninsula, which present some characteristics different from the other rock engravings known in the Península. In first place the total lack of a narrative character must be underlined, implying that the idea is transmitted through symbols. Essentially the set is formed by geometric scenes, mainly cycles associated with pictures of steps and standing stones. There do exist several schematic motives of weapons and feet as well. On one of the rocks there exists a Roman inscription. The study centers on the circular motives and their associations with other geometric motives, which suggest a possible solar cult, especially in view of the steps which can define the image of a cart, which could be identified with the image of the solar cart. Similarly, on other rock there appear a series of five-spiked stars associated in one case to weapons and in another with foot prints, which provide evidence for a solar cult. In any case, the symbolic character of the figures represented seems to imply the abstraction of a cult, with a magic religious character, in which the idea of the star cult presides the rock symbolism. From the study of the arms represented and because of the Roman inscription one could assign to the set of engravings a chronology which could go from the megalithic to the time of romanization.

  17. Metallic species in atmospheric particulate matter in Las Palmas de Gran Canaria.

    PubMed

    Cancio, J López; Castellano, A Vera; Hernández, M Chaar; Bethencourt, R García; Ortega, E Macías

    2008-12-30

    In this work, we quantified the total, water-soluble and insoluble fractions of 12 metallic species (Na, Ca, K, Mg, Fe, Zn, Cr, Ni, Cu, Cd, Pb and Mn) present in total suspended particulates (TSP) in an urban area with heavy traffic (about 80 000 vehicles/day) of Las Palmas de Gran Canaria (Canary Islands). Experimental measurements were made from July to December 2003 on a total of 42 samples (7 per month). Particulate matter (TSP) was collected in fiber filters and high volume samplers. PM10 levels were estimated assuming the PM10 fraction is about 70% of all TSP. Total fractions was determined gravimetrically. Water-soluble fraction was extracted by sonication. Concentrations of metallic elements were analyzed by flame atomic absorption spectrophotometer. Temporal changes in the concentrations of the target elements were examined and a multivariate approach used to identify the primary sources for each species. Mean value for TSP is 71.92microg/m3. The water-soluble fraction consisted mainly of Na, Ca, Mg, and K. The insoluble fraction contained higher concentrations of all elements than the soluble except Na. In the water-soluble fraction, Na, K, Ca and Mg were found to come mainly from natural sources; Cr, Pb, Cd, Ni, Zn and Cu from anthropogenic sources.

  18. Understanding Ground Motion in Las Vegas: Insights from Data Analysis and Two-Dimensional Modeling

    SciTech Connect

    Rodgers, A; Tkalcic, H; McCallen, D

    2004-02-05

    Seismic ground motions are amplified in low velocity sedimentary basins relative to adjacent sites on high velocity hard rock. We used historical recordings of NTS nuclear explosions and earthquake recordings in Las Vegas Valley to quantify frequency-dependent basin amplification using Standard Spectral Ratios. We show that amplifications, referred to as site response, can reach a factor of 10 in the frequency band 0.4-2.0 Hz. Band-averaged site response between 0.4-2.0 Hz is strongly correlated with basin depth. However, it is also well known that site response is related to shallow shear-wave velocity structure. We simulated low frequency (f<1Hz) ground motion and site response with two-dimensional elastic finite difference simulations. We demonstrate that physically plausible models of the shallow subsurface, including low velocity sedimentary structure, can predict relative amplification as well as some of the complexity in the observed waveforms. This study demonstrates that site response can be modeled without invoking complex and computationally expensive three-dimensional structural models.

  19. Recovery of Durvillaea antarctica (Durvilleales) inside and outside Las Cruces Marine Reserve, Chile.

    PubMed

    Castilla, J C; Campo, M A; Bustamante, R H

    2007-07-01

    We present the results for over two decades of monitoring on intertidal food-gatherers and the population of the low rocky shore dweller kelp Durvillaea antarctica, a short-distance disperser, inside and outside the no-take marine reserve, Estacion Costera de Investigaciones Marinas (ECIM), at Las Cruces, central Chile. It was hypothesized that protection of an initially extremely depleted population would recover by recolonizing first the no-take area and then adjacent non-protected (exploited) areas. We found that recovery of D. antarctica occurred slowly inside ECIM, with increase in density and biomass, of up to three orders of magnitude as compared to an adjacent non-protected area, which showed approximately 2-yr delay. These results suggest that the kelp population inside ECIM was likely regulated via intraspecific competition, which did not occur outside. Results showed no evidence for juvenile vs. adult density dependence other than a weak relationship for the central area of ECIM. These findings also suggest that the population recovery and cross-boundary seeding subsides affected the population dynamics. Understanding these dynamics may enhance management and conservation policies. Our work highlights the critical value of baseline and long-term comparative studies in marine no-take protected and non-protected areas for understanding how population processes respond to human and conservation practices.

  20. Episodic Impacts from California Wildfires Identified in Las Vegas Near-Road Air Quality Monitoring.

    PubMed

    Kimbrough, Sue; Hays, Michael; Preston, Bill; Vallero, Daniel A; Hagler, Gayle S W

    2016-01-05

    Air pollutant concentrations near major highways are usually attributed to a combination of nearby traffic emissions and regional background, and generally presumed to be additive in nature. During a near-road measurement study conducted in Las Vegas, NV, the effects of distant wildfires on regional air quality were indicated over a several day period in the summer of 2009. Area-wide elevated particulate levoglucosan (maximum of 0.83 μg/m(3)) and roadside measurements of ultraviolet light-absorbing particulate matter (UVPM) in comparison to black carbon (Delta-C) were apparent over the three-day period. Back-trajectory modeling and satellite images supported the measurement results and indicated the transport of air pollutants from wildfires burning in southern California. Separating roadside measurements under apparent biomass burning event (Delta-C > 1000 ng m(-3)) and nonevent (Delta-C < 1000 ng m(-3)) periods, and constraining to specific days of week, wind speed range, wind direction from the road and traffic volume range, roadside carbon monoxide, black carbon, total particle number count (20-200 nm), and accumulation mode particle number count (100-200 nm) increased by 65%, 146%, 58%, and 366%, respectively, when biomass smoke was indicated. Meanwhile, ultrafine particles (20-100 nm) decreased by 35%. This episode indicates that the presence of aged wildfire smoke may interact with freshly emitted ultrafine particles, resulting in a decrease of particles in the ultrafine mode.

  1. [Description of a staphylococcal alimentary poisoning outbreak in Las Rosas, Santa Fe Province, Argentina].

    PubMed

    Brizzio, Aníbal A; Tedeschi, Fabián A; Zalazar, Fabián E

    2011-01-01

    On February 2008, a suspected foodborne outbreak was reported in Las Rosas (Santa Fe Province, Argentina). The formal procedures indicated that an undetermined number of individuals had experienced food poisoning following consumption of vegetable cannelloni bought at a local shop. The manufacturer establishment was audited. Samples from the suspected food, as well as environmental samples and swabs from food handlers were obtained and involved subjects were interviewed. Remnants of ingested food were also obtained. Routine microbiological procedures of the foodborne outbreak revealed the presence of coagulase positive S. aureus subspecies aureus in samples from ingested and raw food, and from manipulators. Indicator microorganisms did not show significant levels and no other foodborne pathogen was isolated. Presence of staphylococcal enterotoxin-producing genes was subsequently investigated, and a positive result for enterotoxin B was shown in S. aureus strains isolated from a food handler as well as from food linked to the outbreak Moreover, these isolates showed 100% similarity by SmaI-PFGE. Timely notification together with coordinated sanitary measures and the availability of appropriate laboratory tools allowed to interrupt the chain of disease transmission by identifying risk and protective factors.

  2. Integrated geophysical methods for studying the karst system of Gruta de las Maravillas (Aracena, Southwest Spain)

    NASA Astrophysics Data System (ADS)

    Martínez-Moreno, F. J.; Galindo-Zaldívar, J.; Pedrera, A.; Teixido, T.; Ruano, P.; Peña, J. A.; González-Castillo, L.; Ruiz-Constán, A.; López-Chicano, M.; Martín-Rosales, W.

    2014-08-01

    In this study we contrast the results of different geophysical methods in order to describe the karst system surrounding of the Gruta de las Maravillas cave (Aracena, Spain). A comprehensive study of the geophysical responses of the known cavity was carried out, after which several sections were studied to detect the karst architecture and cave continuity. To ensure precision, the inner 3D-topography of the cave was determined by classical geodetic techniques and a digital terrain model was performed with differential GPS. The microgravity method was used to obtain the residual gravity map of the entire study zone, whose minima could be related to caves. Then, the negative gravity anomalies were analyzed to plan several lines for implementing further geophysical methods: magnetic profiles (MP), electrical resistivity tomography (ERT), induced polarization (IP), 2D seismic prospection (refraction tomography and reflection sections) and ground penetrating radar (GPR). The resulting models for each line explored were integrated with detailed geological maps to establish the unknown continuity of the caves. Finally, we discuss the suitability of each geophysical technique for cave detection in marble with sulfur host rock and propose the best procedures to constrain their geometries.

  3. Prevalence of ectoparasitic arthropods on wild animals and cattle in the Las Merindades area (Burgos, Spain).

    PubMed

    Domínguez-Peñafiel, G; Giménez-Pardo, C; Gegúndez, Mi; Lledó, L

    2011-08-01

    This paper reports the prevalence of ectoparasitic arthropods in sampled groups of wild (n = 128; 16 species) and domestic (n = 69; 3 species) animals in the Las Merindades area of the Province of Burgos, Spain. The study revealed that wild animals were more infested and with a wider variety of ectoparasites than domestic animals. The parasitic prevalence was 67% for wild animals and 48% for livestock. In this way, 39% of animals were infected by ticks. Ixodes ricinus and Ixodes hexagonus were the most prevalent species whereas Dermacentor reticulatus showed affinity for the fox and wolf. The overall prevalence of parasitisation by fleas was 27%. Ctenophthalmus spp. showed the wider range host in wild animals, while Pulex irritans was the most frequent specie found. The parasitic prevalences by lice (Trichodectes melis, Trichodectes canis and Trichodectes mustelae) and by mite (Neotrombicula spp., Laelaps agilis and Sarcoptes scabiei) were 4% and 12%, respectively. In both cases only wild animals were found parasited.

  4. Exploring the unified class of Type II Supernovae with the Las Cumbres Observatory Global Telescope Network

    NASA Astrophysics Data System (ADS)

    Valenti, Stefano; Howell, Dale Andrew; Sand, David J.; Arcavi, Iair; Hosseinzadeh, Griffin; McCully, Curtis

    2015-01-01

    Traditionally Type II supernovae (SNe) have been separated into two distinct classes based on the shape of their light curves after peak: Type II plateau (IIP) and Type II linear (IIL) SNe. Recent works suggest that Type II SNe form a continuum of objects from a single progenitor system. Here we present data for a set of Type II SNe collected with the Las Cumbres Observatory Global Telescope (LCOGT) Network and observed simultaneously with UVOT-Swift. In the growing sample of Type II SNe, we search for clear evidence to distinguish the two classes. SNe IIL show a similar drop at the end of their short steep plateau that resemble the drop visible in SNe IIP. We show that also at early phase SNe IIP and IIL are similar both in the UV and in the optical. Our analysis is consistent with the scenario that SNe IIP and IIL come from similar progenitors but with SN IIL progenitors having been stripped of their hydrogen envelope before explosion. While SNe IIL are on average more luminous than SNe IIP, we show that they both produce a comparable amount of nickel.

  5. Large-scale galaxy distribution in the Las Campanas Redshift Survey

    NASA Astrophysics Data System (ADS)

    Doroshkevich, A. G.; Tucker, D. L.; Fong, R.; Turchaninov, V.; Lin, H.

    2001-04-01

    We make use of three-dimensional clustering analysis, inertia tensor methods, and the minimal spanning tree technique to estimate some physical and statistical characteristics of the large-scale galaxy distribution and, in particular, of the sample of overdense regions seen in the Las Campanas Redshift Survey (LCRS). Our investigation provides additional evidence for a network of structures found in our core sampling analysis of the LCRS: a system of rich sheet-like structures, which in turn surround large underdense regions criss-crossed by a variety of filamentary structures. We find that the overdense regions contain ~40-50 per cent of LCRS galaxies and have proper sizes similar to those of nearby superclusters. The formation of such structures can be roughly described as a non-linear compression of protowalls of typical cross-sectional size ~20-25h-1Mpc this scale is ~5 times the conventional value for the onset of non-linear clustering - to wit, r0, the autocorrelation length for galaxies. The comparison with available simulations and theoretical estimates shows that the formation of structure elements with parameters similar to those observed is presently possible only in low-density cosmological models, Ωmh~0.2-0.3, with a suitable large-scale bias between galaxies and dark matter.

  6. Indicator pathogens, organic matter and LAS detergent removal from wastewater by constructed subsurface wetlands

    PubMed Central

    2014-01-01

    Background Constructed wetland is one of the natural methods of municipal and industrial wastewater treatments with low initial costs for construction and operation as well as easy maintenance. The main objective of this study is to determine the values of indicator bacteria removal, organic matter, TSS, ammonia and nitrate affecting the wetland removal efficiency. Results The average concentration of E. coli and total coliform in the input is 1.127 × 1014 and 4.41 × 1014 MPN/100 mL that reached 5.03 × 1012 and 1.13 × 1014 MPN/100 mL by reducing 95.5% and 74.4% in wetland 2. Fecal streptococcus reached from the average 5.88 × 1014 in raw wastewater to 9.69 × 1012 in the output of wetland 2. Wetland 2 could reduce 1.5 logarithmic units of E. coli. The removal efficiency of TSS for the wetlands is 68.87%, 71.4%, 57.3%, and 66% respectively. Conclusions The overall results show that wetlands in which herbs were planted had a high removal efficiency about the indicator pathogens, organic matter, LAS detergent in comparison to a control wetland (without canes) and could improve physicochemical parameters (DO, ammonia, nitrate, electrical conductivity, and pH) of wastewater. PMID:24581277

  7. [Epidemiology of sexually transmitted diseases in the mine area of Las Claritas, Bolivar State, Venezuela].

    PubMed

    González-O, N; Rodríguez-Acosta, A

    2000-06-01

    The primordial objective of this study was to carry out an epidemiological analysis of sexually transmitted diseases (STD) in terms of sensed morbidity and real morbidity in the mining region of "Las Claritas", Bolivar State, Venezuela, during the third trimester of 1998. The epidemiological characteristics of time, people and place are interlaced, giving a relationship included within the Epidemiological Triad, that represents this work's conceptual framework; defining both, the determinant and the conditioning factors of the presence of STDs in the zone. The clinical interrogatory was partially steered towards the participant's sensed morbidity. A mostly feminine population is described (65%), with a low scholarly level in the general population and a high index of foreigners among the evaluated patients; with 48.72% of stable unions in the interviewees. From 166 evaluated patients, 27.70% referred to have had some STD episode, being syphilis and blenorrhagia the most frequently reported. In the survey, there was a general hush concerning the presence of STDs; but, key informants such as the medicine retailers, revealed a higher presence of these diseases, which are wrongly treated by automedication. These are important results, since they let opened a space for the epidemiological evaluation in the zone, in the various health, sanitary, environmental and social aspects and mainly, by the individual's quality of life expectations.

  8. Random analysis of bearing capacity of square footing using the LAS procedure

    NASA Astrophysics Data System (ADS)

    Kawa, Marek; Puła, Wojciech; Suska, Michał

    2016-09-01

    In the present paper, a three-dimensional problem of bearing capacity of square footing on random soil medium is analyzed. The random fields of strength parameters c and φ are generated using LAS procedure (Local Average Subdivision, Fenton and Vanmarcke 1990). The procedure used is re-implemented by the authors in Mathematica environment in order to combine it with commercial program. Since the procedure is still tested the random filed has been assumed as one-dimensional: the strength properties of soil are random in vertical direction only. Individual realizations of bearing capacity boundary-problem with strength parameters of medium defined the above procedure are solved using FLAC3D Software. The analysis is performed for two qualitatively different cases, namely for the purely cohesive and cohesive-frictional soils. For the latter case the friction angle and cohesion have been assumed as independent random variables. For these two cases the random square footing bearing capacity results have been obtained for the range of fluctuation scales from 0.5 m to 10 m. Each time 1000 Monte Carlo realizations have been performed. The obtained results allow not only the mean and variance but also the probability density function to be estimated. An example of application of this function for reliability calculation has been presented in the final part of the paper.

  9. Neandertal mandibles from the Sima de las Palomas del Cabezo Gordo, Murcia, southeastern Spain.

    PubMed

    Walker, Michael J; Lombardi, A Vincent; Zapata, Josefina; Trinkaus, Erik

    2010-06-01

    The Middle Paleolithic levels of the Sima de las Palomas have yielded eight partial mandibles (Palomas 1, 6, 7, 23, 49, 59, 80, and 88). Palomas 7, 49, 80, and 88 are immature, and Palomas 49, 59, 80, and 88 are among the latest Neandertals (approximately 40,000 cal BP). Palomas 1 is geologically older (approximately 50,000-60,000 cal BP), and the other three were found ex situ. The mandibles exhibit a suite of characteristics that align them with the Neandertals among later Pleistocene humans, including symphyseal morphology, symphyseal orientation, corpus robusticity, distal mental foramen position, retromolar space presence, wide immature dental arcade, and high-coronoid process with an asymmetrical mandibular notch. However, Palomas 6 lacks a retromolar space, Palomas 59 has a narrow lateral corpus, and Palomas 80 has a mesial mental foramen and open mandibular foramen. The Palomas mandibles therefore help to document that the late Middle Paleolithic of southern Iberia was the product of Neandertals. They also reinforce the presence of variability in both metric and discrete aspects of Neandertal mandibular morphology, both within and across samples, some of which may be temporal and/or geographic in nature.

  10. SOURCE AND PATHWAY DETERMINATION FOR BERYLLIUM FOUND IN BECHTEL NEVADA NORTH LAS VEGAS FACILITIES

    SciTech Connect

    BECHTEL NEVADA

    2004-07-01

    In response to the report ''Investigation of Beryllium Exposure Cases Discovered at the North Las Vegas Facility of the National Nuclear Security Administration'', published by the U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA) in August 2003, Bechtel Nevada (BN) President and General Manager Dr. F. A. Tarantino appointed the Beryllium Investigation & Assessment Team (BIAT) to identify both the source and pathway for the beryllium found in the North Las Vegas (NLV) B-Complex. From September 8 to December 18, 2003, the BIAT investigated the pathway for beryllium and determined that a number of locations existed at the Nevada Test Site (NTS) which could have contained sufficient quantities of beryllium to result in contamination if transported. Operations performed in the B-1 Building as a result of characterization activities at the Engine Maintenance, Assembly, and Disassembly (EMAD); Reactor Maintenance, Assembly, and Disassembly (RMAD); Test Cells A and C; and the Central Support Facility in Area 25 had the greatest opportunity for transport of beryllium. Investigative monitoring and sampling was performed at these sites with subsequent transport of sample materials, equipment, and personnel from the NTS to the B-1 Building. The timeline established by the BIAT for potential transport of the beryllium contamination into the B-1 Building was from September 1997 through November 2002. Based on results of recently completed swipe sampling, no evidence of transport of beryllium from test areas has been confirmed. Results less than the DOE beryllium action level of 0.2 ???g/100 cm2 were noted for work support facilities located in Area 25. All of the identified sites in Area 25 worked within the B-1 tenant's residency timeline have been remediated. Legacy contaminants have either been disposed of or capped with clean borrow material. As such, no current opportunity exists for release or spread of beryllium contamination. Historical

  11. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA

    PubMed Central

    Goossens, Dirk

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g-1 in topsoil and bedrock, and more than 0.03 μg m-3 in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m-3. The results of this study are important because the NDRA is visited by more than 300,000 people annually. PMID:25897667

  12. Surface and Airborne Arsenic Concentrations in a Recreational Site near Las Vegas, Nevada, USA.

    PubMed

    Goossens, Dirk; Buck, Brenda J; Teng, Yuanxin; McLaurin, Brett T

    2015-01-01

    Elevated concentrations of arsenic, up to 7058 μg g(-1) in topsoil and bedrock, and more than 0.03 μg m(-3) in air on a 2-week basis, were measured in the Nellis Dunes Recreation Area (NDRA), a very popular off-road area near Las Vegas, Nevada, USA. The elevated arsenic concentrations in the topsoil and bedrock are correlated to outcrops of yellow sandstone belonging to the Muddy Creek Formation (≈ 10 to 4 Ma) and to faults crossing the area. Mineralized fluids moved to the surface through the faults and deposited the arsenic. A technique was developed to calculate airborne arsenic concentrations from the arsenic content in the topsoil. The technique was tested by comparing calculated with measured concentrations at 34 locations in the NDRA, for 3 periods of 2 weeks each. We then applied it to calculate airborne arsenic concentrations for more than 500 locations all over the NDRA. The highest airborne arsenic concentrations occur over sand dunes and other zones with a surficial layer of aeolian sand. Ironically these areas show the lowest levels of arsenic in the topsoil. However, they are highly susceptible to wind erosion and emit very large amounts of sand and dust during episodes of strong winds, thereby also emitting much arsenic. Elsewhere in the NDRA, in areas not or only very slightly affected by wind erosion, airborne arsenic levels equal the background level for airborne arsenic in the USA, approximately 0.0004 μg m(-3). The results of this study are important because the NDRA is visited by more than 300,000 people annually.

  13. The Membrane Protein LasM Promotes the Culturability of Legionella pneumophila in Water

    PubMed Central

    Li, Laam; Faucher, Sébastien P.

    2016-01-01

    The water-borne pathogen Legionella pneumophila (Lp) strongly expresses the lpg1659 gene in water. This gene encodes a hypothetical protein predicted to be a membrane protein using in silico analysis. While no conserved domains were identified in Lpg1659, similar proteins are found in many Legionella species and other aquatic bacteria. RT-qPCR showed that lpg1659 is positively regulated by the alternative sigma factor RpoS, which is essential for Lp to survive in water. These observations suggest an important role of this novel protein in the survival of Lp in water. Deletion of lpg1659 did not affect cell morphology, membrane integrity or tolerance to high temperature. Moreover, lpg1659 was dispensable for growth of Lp in rich medium, and during infection of the amoeba Acanthamoeba castellanii and of THP-1 human macrophages. However, deletion of lpg1659 resulted in an early loss of culturability in water, while over-expression of this gene promoted the culturability of Lp. Therefore, these results suggest that lpg1659 is required for Lp to maintain culturability, and possibly long-term survival, in water. Since the loss of culturability observed in the absence of Lpg1659 was complemented by the addition of trace metals into water, this membrane protein is likely a transporter for acquiring essential trace metal for maintaining culturability in water and potentially in other metal-deprived conditions. Given its role in the survival of Lp in water, Lpg1659 was named LasM for Legionella aquatic survival membrane protein. PMID:27734007

  14. Flow and transport at the Las Cruces trench site: Experiment IIb

    SciTech Connect

    Vinson, J.; Hills, R.G.; Wierenga, P.J.; Young, M.H.

    1997-07-01

    The US Nuclear Regulatory Commission (NRC) has been directed by Congress in the Low Level Waste Policy Act of 1980 to develop regulatory guidance and assist the individual states and compacts in siting and assessing future low level radioactive waste (LLW) disposal facilities. Three water flow and solute transport experiments were performed as part of a comprehensive field trench study near Las Cruces, New Mexico to test deterministic and stochastic models of vadose zone flow and transport. This report presents partial results from the third experiment (experiment IIb). Experiments IIa and b were conducted on the North side of the trench, on a plot 1.22 m wide by 12 m long, perpendicular to the trench. The area was drip irrigated during two time periods with water containing a variety of tracers. The advance of the water front during the two irrigation episodes was measured with tensiometers and neutron probes. Solute front positions were determined from soil solution sampling through suction samplers and from disturbed sampling. The results from experiment IIb show predominantly downward water movement through the layered unsaturated soil, as evidenced from neutron probe data and gravimetric sampling. Tritium plumes were only half as deep and half as wide as the water plumes at 310 days after the beginning of experiment IIb. Chromium, applied as Cr(VI), moved a readily as, and similar to tritium, but there was a loss of mass due to reduction of Cr(VI) to Cr(III). Chloride and nitrate, initially present at high concentrations in the soil solution, were displaced by the low concentration irrigation water, resulting in chloride and nitrate concentration distributions that looked like negative images of the tritium distributions. The extensive data presented should serve well as a data base for model testing.

  15. The Las Cumbres Observatory (LCOGT) Network for NEO and Solar System Science

    NASA Astrophysics Data System (ADS)

    Lister, Tim; Greenstreet, Sarah; Gomez, Edward; Christensen, Eric J.; Larson, Stephen M.

    2016-01-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) has deployed a homogeneous telescope network of nine 1-meter telescopes to four locations in the northern and southern hemispheres, with a planned network size of twelve 1-meter telescopes at 6 locations. This 1-meter network is in addition to the two 2-meter Faulkes Telescopes that have been operating since 2005. This network is very versatile and is designed to respond rapidly to target of opportunity events and also to perform long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects e.g. Near-Earth Objects (NEOs), comets, asteroids and Kuiper Belt Objects and also for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network has been fully operational since 2014 May, and observations are being executed remotely and robotically. Future expansion to sites in the Canary Islands and Tibet are planned for 2016-2017.I will describe the Solar System science research that is being carried out using the LCOGT Network with highlights from the LCOGT NEO Follow-up Network, long-term monitoring of the Rosetta spacecraft target comet 67P and comet C/2013 A1 (Siding Spring) and work on Kuiper Belt Object occultation targets, including Pluto.

  16. The Las Cumbres Observatory (LCOGT) Network for NEO and Solar System Science

    NASA Astrophysics Data System (ADS)

    Lister, Tim; Greenstreet, Sarah; Gomez, Edward; Christensen, Eric; Larson, Stephen

    2015-11-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) has deployed a homogeneous telescope network of nine 1-meter telescopes to four locations in the northern and southern hemispheres, with a planned network size of twelve 1-meter telescopes at 6 locations. This 1-meter network is in addition to the two 2-meter Faulkes Telescopes that have been operating since 2005. This network is very versatile and is designed to respond rapidly to target of opportunity events and also to perform long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects e.g. Near-Earth Objects (NEOs), comets, asteroids and Kuiper Belt Objects and also for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network has been fully operational since 2014 May, and observations are being executed remotely and robotically. Future expansion to sites in the Canary Islands and Tibet are planned for 2016-2017.I will describe the Solar System science research that is being carried out using the LCOGT Network with highlights from the LCOGT NEO Follow-up Network, long-term monitoring of the Rosetta spacecraft target comet 67P and comet C/2013 A1 (Siding Spring) and work on Kuiper Belt Object occultation targets, including Pluto.

  17. Geology of Volcan Las Navajas, a pleistocene trachyte/peralkaline rhyolite volcanic center in Nayarit, Mexico

    SciTech Connect

    Hegre, J.A.; Nelson, S.A.

    1985-01-01

    Volcan Las Navajas, located in the northwestern portion of the Mexican Volcanic Belt has produced a sequence of volcanic rocks with compositions in marked contrast to the predominantly calc-alkaline volcanoes which predominate in this part of Mexico. The oldest exposed lavas consist of trachytes with 63% SiO/sub 2/, 6% FeO*, and 500 ppm Zr along with comenditic rhyolites with 68% SiO/sub 2/, 5% FeO*, 800 ppm Zr, and an agpaitic index of 1.0. These lavas were followed by the eruption of a comenditic ash-flow tuff and the formation of a caldera 2.7 km in diameter. This caldera was subsequently filled by eruptions of pantelleritic rhyolite obsidian lava flows with 72% SiO/sub 2/, 8% FeO*, 1100 ppm Zr, and an agpaitic index of 1.5 to 1.9. A second caldera was then formed which is offset to the south of the main eruptive vents for previous eruptions. This younger caldera has a diameter of about 4.8 km and its southern walls have been covered by calc-alkaline andesitic lavas erupted from nearby Sanganguey volcano. Volcanoclastic sediments in the floor of the younger caldera have been tilted and faulted in a manner suggestive of late stage resurgence. Subsequent eruptions within the caldera, however, have been restricted to calc-alkaline andesites. Tectonically, the area in which this volcano occurs appears to have been undergoing a crustal rifting event since the Pliocene. The occurrence of these peralkaline rocks lends further support to such a hypothesis.

  18. Response times and outcomes for cardiac arrests in Las Vegas casinos.

    PubMed

    Karch, S B; Graff, J; Young, S; Ho, C H

    1998-05-01

    This study was conducted to measure emergency medical services (EMS) response times in sudden out-of-hospital cardiac arrests and relate those times to probability of survival in cardiac arrest victims in Las Vegas casino-hotels from January 1993 to June 1996. Times from 911 activation to casino arrival and casino arrival to arrival at patient's side (time to first defibrillatory shock), as well as survival to hospital discharge, were studied with regression analysis. Sixty patients survived (29.3%). Response times to the hotels for survivors and nonsurvivors were similar (4.8 v 5.6 min, P = .44). However, times from arrival at the casino to arrival at the patient's side (5.0 v 6.88 min, P = .01) and elapsed times from 911 activation until first shock (9.88 v 12.46 min, P = .02) were substantially longer for nonsurvivors. Model fitting disclosed that with a 911-to-shock time of 4 minutes, survival probability was 36%. Odds decreased by 5% each minute, to 19% after 23 minutes. Ventricular fibrillation was the most common initial rhythm (187 cases) and was associated with the shortest times from 911 to shock (10.7 +/- 7.8 min). There was a strong trend to increased survival with ventricular fibrillation. The 911-to-shock times in this study are considerably better than in other published reports for large metropolitan EMS systems, but the time from 911 to shock was nearly 3 minutes longer for nonsurvivors, and even those defibrillated at 4 minutes had only a 36% chance of survival. New measures, including use of the automatic external difibrillator, to reduce the "vertical" response are urgently needed.

  19. Variations in alluvial style of Tertiary units in response to tectonism, Las Monas area, middle Magdalena valley, Colombia

    SciTech Connect

    Jordan, D.W.; Siemers, C.T.

    1989-03-01

    Detailed sedimentologic and petrographic analyses of Tertiary alluvial sandstone outcrops within and east of producing oil fields in the Las Monas area in Colombia, South America, indicate that depositional style changed from fluvial-deltaic to braided streams atop alluvial fans to high-sinuosity meandering streams in response to uplifts in the surrounding areas. Diverse paleocurrent trends in the Tertiary formations in the perimeter area demonstrate that streams flowed northeast and northwest. Streams in the oil field had easterly and southerly components. Source areas contributing sediment were different and reflected uplifts to the west and south of the Las Monas area. Petrographic composition of sandstones that have easterly and southerly paleocurrent trends in the field area contain more feldspar and less polycrystalline strained quartz than sandstones having a northerly trend in the perimeter area. Sandstones in the field area represent an unroofing of a western granitic terrain, possibly in the ancestral Central Cordillera.

  20. Estudio del comportamiento tribologico y de las interacciones de superficie de nuevos nanofluidos ionicos

    NASA Astrophysics Data System (ADS)

    Espinosa Rodriguez, Tulia

    tribocorrosion processes. The formation of a coating layer on magnesium alloys from phosphonate imidazolium ionic liquids by immersion and by chronoamperometry has been described. The new coatings reduce the abrasive wear in the magnesium-aluminium alloy but they are not effective in the magnesium-zinc alloy, which prevent the formation of continuous coatings. Los liquidos ionicos son sales liquidas a temperatura ambiente o bajas temperaturas que presentan excelentes propiedades fisico-quimicas. En el presente trabajo se estudian como lubricantes en problemas tribologicos complejos como la lubricacion de metales contra si mismos, el desarrollo de lubricantes base agua y de nuevas superficies autolubricadas. Cuando no es posible reducir la friccion y desgaste mediante lubricacion, como en las aleaciones de magnesio, los liquidos ionicos se han estudiado como precursores de recubrimientos protectores. Se han determinado las interacciones superficiales y los procesos de corrosion sobre cobre y sobre acero con diferentes liquidos ionicos proticos y aproticos para desarrollar nuevos lubricantes y aditivos. En el contacto cobre/cobre, excepto el liquido ionico protico derivado del oleato, todos los liquidos ionicos estudiados presentan mejor comportamiento tribologico que el lubricante comercial Polialfaolefina 6. En el contacto acero/zafiro, los nuevos liquidos ionicos proticos son buenos lubricantes cuando se utilizan en estado puro, y, como aditivos en agua, generan peliculas adsorbidas sobre la superficie del metal reduciendo la friccion y el desgaste tras la evaporacion del agua. Para evitar el periodo de alta friccion inicial en presencia de agua, se han generado peliculas superficiales de liquido ionico sobre el acero en condiciones estaticas. El mejor comportamiento lubricante tanto en el contacto cobre/cobre como en el contacto acero/zafiro se obtiene para el liquido ionico protico derivado del anion adipato, con dos grupos carboxilicos. Las interacciones de los grupos

  1. DISYUNTIVAS EN LAS CONCEPCIONES SOBRE AUTONOMÍA Y BENEFICENCIA QUE AFECTAN LA TERAPÉUTICA DEL INTENTO SUICIDA1

    PubMed Central

    Mondragón, Liliana; Monroy, Zuraya; Ito, Ma. Emily; Medina-Mora, Dra. Ma. Elena

    2010-01-01

    El objetivo del trabajo es conocer las disyuntivas entre los principios de beneficencia y autonomía, que se presentan en la relación médico-paciente, durante la terapéutica del intento de suicidio. La investigación se realizó en dos hospitales psiquiátricos de la Ciudad de México. La muestra incluyó a tres sujetos con intento de suicidio, mayores de 18 años, que eran atendidos en consulta externa a causa de una lesión autoinfligida en el último año, y a tres psiquiatras que trataban a estos pacientes. La información se obtuvo previo consentimiento informado en entrevistas individuales. Se llevó a cabo un análisis de discurso argumentado para encontrar los significados que los participantes otorgaron a los principios bioéticos y las posibles disyuntivas entre éstos. Las discordancias entre la beneficencia y la autonomía estuvieron relacionadas con el beneficio del tratamiento, el respeto por los valores y las creencias de los pacientes, entre otros. Este trabajo presenta consideraciones éticas relevantes en el escenario clínico, al ofrecer al psiquiatra un análisis bioético que le permita actuar de acuerdo con la beneficencia y respetando la autonomía del paciente frente a casos de intento de suicidio y, de esta forma procurar una mejor atención para ellos. PMID:20830214

  2. Recent variation of the Las Vacas Glacier Mt. Aconcagua region, Central Andes, Argentina, based on ASTER stereoscopic images

    NASA Astrophysics Data System (ADS)

    Lenzano, M. G.; Leiva, J. C.; Lenzano, L.

    2010-01-01

    This work presents the results of the ASTER stereoscopic image processing to calculate the volume changes of Las Vacas Glacier. The processing of medium resolution satellite images (ASTER level 1A - pixel 15 m) from February 2001 and 2007 was performed applying the satellite digital photogrammetry method (Kääb, 2005). The comparison of the two generated DTM returns results that are acceptable within the parameters and precisions that can be obtained with this kind of sensor and the processing methodology.

  3. DISYUNTIVAS EN LAS CONCEPCIONES SOBRE AUTONOMÍA Y BENEFICENCIA QUE AFECTAN LA TERAPÉUTICA DEL INTENTO SUICIDA.

    PubMed

    Mondragón, Liliana; Monroy, Zuraya; Ito, Ma Emily; Medina-Mora, Dra Ma Elena

    2010-06-01

    El objetivo del trabajo es conocer las disyuntivas entre los principios de beneficencia y autonomía, que se presentan en la relación médico-paciente, durante la terapéutica del intento de suicidio.La investigación se realizó en dos hospitales psiquiátricos de la Ciudad de México. La muestra incluyó a tres sujetos con intento de suicidio, mayores de 18 años, que eran atendidos en consulta externa a causa de una lesión autoinfligida en el último año, y a tres psiquiatras que trataban a estos pacientes. La información se obtuvo previo consentimiento informado en entrevistas individuales. Se llevó a cabo un análisis de discurso argumentado para encontrar los significados que los participantes otorgaron a los principios bioéticos y las posibles disyuntivas entre éstos.Las discordancias entre la beneficencia y la autonomía estuvieron relacionadas con el beneficio del tratamiento, el respeto por los valores y las creencias de los pacientes, entre otros. Este trabajo presenta consideraciones éticas relevantes en el escenario clínico, al ofrecer al psiquiatra un análisis bioético que le permita actuar de acuerdo con la beneficencia y respetando la autonomía del paciente frente a casos de intento de suicidio y, de esta forma procurar una mejor atención para ellos.

  4. Elucidating Key Motifs Required for Arp2/3-Dependent and Independent Actin Nucleation by Las17/WASP

    PubMed Central

    Urbanek, Agnieszka N.; Smaczynska-de Rooij, Iwona I.

    2016-01-01

    Actin nucleation is the key rate limiting step in the process of actin polymerization, and tight regulation of this process is critical to ensure actin filaments form only at specific times and at defined regions of the cell. Arp2/3 is a well-characterised protein complex that can promote nucleation of new filaments, though its activity requires additional nucleation promotion factors (NPFs). The best recognized of these factors are the WASP family of proteins that contain binding motifs for both monomeric actin and for Arp2/3. Previously we demonstrated that the yeast WASP homologue, Las17, in addition to activating Arp2/3 can also nucleate actin filaments de novo, independently of Arp2/3. This activity is dependent on its polyproline rich region. Through biochemical and in vivo analysis we have now identified key motifs within the polyproline region that are required for nucleation and elongation of actin filaments, and have addressed the role of the WH2 domain in the context of actin nucleation without Arp2/3. We have also demonstrated that full length Las17 is able to bind liposomes giving rise to the possibility of direct linkage of nascent actin filaments to specific membrane sites to which Las17 has been recruited. Overall, we propose that Las17 functions as the key initiator of de novo actin filament formation at endocytic sites by nucleating, elongating and tethering nascent filaments which then serve as a platform for Arp2/3 recruitment and function. PMID:27637067

  5. Analysis of the real estate market in Las Vegas: Bubble, seasonal patterns, and prediction of the CSW indices

    NASA Astrophysics Data System (ADS)

    Zhou, Wei-Xing; Sornette, Didier

    2008-01-01

    We analyze 27 house price indices of Las Vegas from June 1983 to March 2005, corresponding to 27 different zip codes. These analyses confirm the existence of a real estate bubble, defined as a price acceleration faster than exponential, which is found, however, to be confined to a rather limited time interval in the recent past from approximately 2003 to mid-2004 and has progressively transformed into a more normal growth rate comparable to pre-bubble levels in 2005. There has been no bubble till 2002 except for a medium-sized surge in 1990. In addition, we have identified a strong yearly periodicity which provides a good potential for fine-tuned prediction from month to month. A monthly monitoring using a model that we have developed could confirm, by testing the intra-year structure, if indeed the market has returned to “normal” or if more turbulence is expected ahead. We predict the evolution of the indices one year ahead, which is validated with new data up to September 2006. The present analysis demonstrates the existence of very significant variations at the local scale, in the sense that the bubble in Las Vegas seems to have preceded the more global USA bubble and has ended approximately two years earlier (mid-2004 for Las Vegas compared with mid-2006 for the whole of the USA).

  6. Aerosol Light Absorption and Scattering in Mexico City: Comparison With Las Vegas, NV, and Los Angeles, CA.

    NASA Astrophysics Data System (ADS)

    Paredes-Miranda, G.; Arnott, W. P.; Gaffney, J. S.; Marley, N. A.; Campbell, D.; Fujita, E.

    2007-12-01

    Aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The primary site in Mexico City was an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP). Similar campaigns were held in Las Vegas, NV in January-February, 2003; and Los Angeles, CA at numerous sites during all seasons from 2003 through 2007. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions. The photoacoustic instrument (PAS) used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In Mexico City the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of Mexico City resulted in more direct solar radiation. Further insight on the meteorological connections and population dynamics will be discussed.

  7. Removal of nutrients and metals by constructed and naturally created wetlands in the Las Vegas Valley, Nevada.

    PubMed

    Adhikari, Achyut R; Acharya, Kumud; Shanahan, Seth A; Zhou, Xiaoping

    2011-09-01

    Increased water use associated with rapid growth in the Las Vegas Valley has inadvertently led to the creation of unique wetland systems in Southern Nevada with an abundance of biological diversity. Constructed and naturally created wetlands in the Las Vegas Valley watershed were studied to characterize and understand their potential role for improving ecosystem services (i.e., water purification). Nutrient and metal removal was assessed at four sites including a natural urban runoff wetland, a constructed urban runoff wetland, a constructed wastewater wetland, and a natural urban runoff/wastewater wetland. Plant nutrient uptake was dependent on ambient nutrient concentrations in water and sediments of specific wetlands, irrespective of the type of plants present. Phosphorus was mostly concentrated in below-ground plant parts whereas nitrogen was concentrated in above-ground parts. As for metalloids, bulrushes were more efficient than cattails at taking up arsenic and selenium. Averaging all the wetland sites and plant species, total nitrogen, phosphorus, arsenic and selenium removal was 924.2, 61.5, 0.30, and 0.38 kg/ha/year, respectively. Our findings suggest that natural and created wetland systems can improve water quality in the Las Vegas Valley watershed for some common pollutants, however, other measures are still needed to improve water quality below regulatory thresholds.

  8. The U.S. Department of Energy Office of Indian Energy Policy and Programs Las Vegas, Nevada, Roundtable Summary

    SciTech Connect

    2011-03-16

    LAS VEGAS EXECUTIVE SUMMARY The Las Vegas, Nevada DOE Tribal Roundtable convened on March 16th, at the Las Vegas Hilton. The meeting was hosted by the Department of Energy (DOE) Office of Indian Policy and Programs (DOE Office of Indian Energy) and facilitated by JR Bluehouse, Program Manager, Udall Foundation’s U.S. Institute for Environmental Conflict Resolution (U.S. Institute). Mr. Bluehouse was assisted by Tamara, Underwood, Program Assistant, U.S. Institute.  Tribal leaders and representatives from multiple tribal governments and communities attended the roundtable. Tracey LeBeau, newly appointed Director of the Office of Indian Energy attended.    LaMont Jackson from DOE’s Office of Electricity attended. Also attending from the administration and federal agencies were Kim Teehee, Senior Policy Advisor for Native American Affairs, The White House; Charlie Galbraith, Associate Director of the Office of Public Engagement and Deputy Associate Director of the Office of Intergovernmental Affairs, The White House; Jodi Gillette, Deputy Assistant Secretary for Policy and Economic Development, the Bureau of Indian Affairs.

  9. Improved estimation of sensible heat flux by a LAS using a Bowen ratio at urban residential area

    NASA Astrophysics Data System (ADS)

    Park, M. S.; Chae, J. H.

    2014-12-01

    A large aperture scintillometer (LAS) data sampled for the period from 1 February to 31 July 2014 at urban residential area in Seoul are modified using the variable Bowen ratio and a net radiation data to determine the space-averaged sensible heat flux (SHF). A LAS system is installed over the rooftop of two buildings with a distance between receiver and transmitter of 535 m, an effective height of 18.4 m, a wind speed sensor at 25.0 m high. The path-averaged building height, roughness length, and displacement length between the receiver and transmitter are 9.2 m, 0.4 m, and 7.1 m, respectively. The Bowen ratio computed at every 30 minute interval by the wind speed and air temperature at 10 and 18 m above the rooftop is found to be well correlated with meteorological variables such as net radiation and mixing ratio. Therefore, it is parameterized as a function of mixing ratio and net radiation. The resulting parameterization is applied to estimate the SHF by LAS. The Monin-Obukhov similarity universal function should be changed according to the atmospheric stability using the sign of net radiation sampled at the same time. It is found that the resulting sensible heat fluxes are available under all atmospheric stability and are much improved compared with those by eddy covariance method.

  10. Contribución al flujo infrarrojo de las estrellas Be de la recombinación dielectrónica del MgII

    NASA Astrophysics Data System (ADS)

    Cruzado, A.; di Rocco, H.; Ringuelet, A.

    Para evaluar la contribución del proceso de recombinación dielectrónica del átomo de MgII al exceso de flujo infrarrojo observado en las estrellas Be, calculamos la energía emitida en las líneas originadas por este proceso. Se evaluaron los efectos de las condiciones físicas del medio, como la temperatura electrónica y la densidad electrónica, sobre el flujo emitido. Se consideró también la influencia de una posible opacidad.

  11. Reconciling Scale Mismatch in Water Governance, Hydro-climatic Processes and Infrastructure Systems of Water Supply in Las Vegas

    NASA Astrophysics Data System (ADS)

    Garcia, M. E.; Alarcon, T.; Portney, K.; Islam, S.

    2013-12-01

    Water resource systems are a classic example of a common pool resource due to the high cost of exclusion and the subtractability of the resource; for common pool resources, the performance of governance systems primarily depends on how well matched the institutional arrangements and rules are to the biophysical conditions and social norms. Changes in water governance, hydro-climatic processes and infrastructure systems occur on disparate temporal and spatial scales. A key challenge is the gap between current climate change model resolution, and the spatial and temporal scale of urban water supply decisions. This gap will lead to inappropriate management policies if not mediated through a carefully crafted decision making process. Traditional decision support and planning methods (DSPM) such as classical decision analysis are not equipped to deal with a non-static climate. While emerging methods such as decision scaling, robust decision making and real options are designed to deal with a changing climate, governance systems have evolved under the assumption of a static climate and it is not clear if these methods are well suited to the existing governance regime. In our study, these questions are contextualized by examining an urban water utility that has made significant changes in policy to adapt to changing conditions: the Southern Nevada Water Authority (SNWA) which serves metropolitan Las Vegas. Like most desert cities, Las Vegas exists because of water; the artesian springs of the Las Vegas Valley once provided an ample water supply for Native Americans, ranchers and later a small railroad city. However, population growth has increased demands far beyond local supplies. The area now depends on the Colorado River for the majority of its water supply. Natural climate variability with periodic droughts has further challenged water providers; projected climate changes and further population growth will exacerbate these challenges. Las Vegas is selected as a case

  12. Microbial characterization and removal of anionic surfactant in an expanded granular sludge bed reactor.

    PubMed

    Delforno, T P; Okada, D Y; Polizel, J; Sakamoto, I K; Varesche, M B A

    2012-03-01

    This study evaluated linear alkylbenzene sulfonate removal in an expanded granular sludge bed reactor with hydraulic retention times of 26 h and 32 h. Sludge bed and separator phase biomass were phylogenetically characterized (sequencing 16S rRNA) and quantified (most probable number) to determine the total anaerobic bacteria and methanogenic Archaea. The reactor was fed with a mineral medium supplemented with 14 mg l(-1)LAS, ethanol and methanol. The stage I-32 h consisted of biomass adaptation (without LAS influent) until reactor stability was achieved (COD removal >97%). In stage II-32 h, LAS removal was 74% due to factors such as dilution, degradation and adsorption. Higher HRT values increased the LAS removal (stage III: 26 h - 48% and stage IV: 32 h - 64%), probably due to increased contact time between the biomass and LAS. The clone libraries were different between samples from the sludge bed (Synergitetes and Proteobacteria) and the separator phase (Firmicutes and Proteobacteria) biomass.

  13. Seepage carbonate mounds in Cenozoic sedimentary sequences from the Las Minas Basin, SE Spain

    NASA Astrophysics Data System (ADS)

    Pozo, M.; Calvo, J. P.; Scopelliti, G.; González-Acebrón, L.

    2016-04-01

    A number of carbonate mounds composed of indurate, strongly folded and/or brecciated calcite and dolomite beds occur interstratified in Cenozoic sedimentary sequences from the Las Minas Basin. Part of the fabric of the rock forming the carbonate mounds is composed of laminated to banded dolostone similar to the host rock but showing contrasted lithification. Moreover, the carbonate deposits of the mounds display aggrading neomorphism of dolomite, partial replacement of dolomite by calcite, calcite cementation, and extensive silicification, locally resulting in box-work fabric. Eight main lithofacies were distinguished in the carbonate mound deposits. In some lithofacies, chert is present as both microcrystalline to fibro-radial quartz and opal, the latter occurring mainly as cement whereas the former replace the carbonate and infill voids. Yet one of the carbonate mounds shows distinctive petrography and geochemical features thus suggesting a distinctive growth pattern. The carbon isotope compositions of calcite from the mound samples range from - 11.56 to - 5.15 δ‰ whilst dolomite is depleted in 13C, with values of - 12.38 to 3.02 δ‰. Oxygen isotopic compositions vary from - 9.42 to - 4.64 δ‰ for calcite and between - 6.68 and 8.19 δ‰ for dolomite. Carbonate in the mounds shows significant enrichment in Co, Cr, Ni and Pb content, especially in the strongly deformed (F-2-2 lithofacies) and brecciated carbonate (F-4). The carbonate deposits show depletion in REE and Y in contrast to that determined in lutite. The formation of the carbonate mounds was related to local artesian seepage thermal water flows of moderate to relative high temperatures. Pressure differences between the low permeability host rock and the circulating fluids accounted for dilational fracturing and brecciation of the host sediment packages, which combined with precipitation of new carbonate and silica mineral phases. Locally, some carbonate mounds developed where groundwater

  14. Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Opal Mountain, Nevada

    USGS Publications Warehouse

    Laney, R.L.

    1981-01-01

    The study is a geohydrologic reconnaissance of about 170 square miles in the Lake Mead National Recreation Area from Las Vegas Wash to Opal Mountain, Nevada. The study is one of a series that describes the geohydrology of the recreation area and that indentifies areas where water supplies can be developed. Precipitation in this arid area is about 5 inches per year. Streamflow is seasonal and extremely variable except for that in the Colorado River, which adjoins the area. Pan evaporation is more than 20 times greater than precipitation; therefore, regional ground-water supplies are meager except near the Colorado River, Lake Mead, and Lake Mohave. Large ground-water supplies can be developed near the river and lakes, and much smaller supplies may be obtained in a few favorable locations farther from the river and lakes. Ground water in most of the areas probably contains more than 1,000 milligrams per liter of dissolved solids, but water that contains less than 1,000 milligrams per liter of dissolved solids can be obtained within about 1 mile of the lakes. Crystalline rocks of metamorphic, intrusive and volcanic origin crop out in the area. These rocks are overlain by conglomerate and mudstone of the Muddy Creek Formation, gravel and conglomerate of the older alluvium, and sand and gravel of the Chemehuevi Formation and younger alluvium. The crystalline rocks, where sufficiently fractured, yield water to springs and would yield small amounts of water to favorably located wells. The poorly cemented and more permeable beds of the older alluvium, Chemehuevi Formation, and younger alluvium are the better potential aquifers, particularly along the Colorado River and Lakes Mead and Mohave. Thermal springs in the gorge of the Colorado River south of Hoover Dam discharge at least 2,580 acre-feet per year of water from the volcanic rocks and metamorphic and plutonic rocks. The discharge is much greater than could be infiltrated in the drainage basin above the springs

  15. Las Cumbres Observatory Global Telescope Network: Keeping Citizen Scientists in the Dark

    NASA Astrophysics Data System (ADS)

    Ross, R. J.

    2012-08-01

    Las Cumbres Observatory Global Telescope Network (LCOGT) is creating a network of telescopes at excellent sites around the world providing 24/7 all sky coverage for astronomical observations. The network of telescopes, ranging in size from 0.4 m to 2.0 m, will be available for both scientific and education users. The LCOGT telescopes are being built quickly and will be deployed soon. The two 2.0 m Faulkes Telescopes, one on Haleakala, Maui (FTN), the other at Siding Spring Observatory, Australia (FTS), are currently in operation. There is also a 0.8 m telescope in the Santa Ynez Valley, California (BOS), which is being used for commissioning and for many local outreach programs. The first 1.0 m telescopes will be heading to Chile and South Africa in 2011 and will each be accompanied by a 0.4 m telescope. Other sites, including Tenerife (Canary Islands, Spain), McDonald Observatory (Texas), Siding Spring (Australia), and Haleakala (Hawaii) will follow, with the possibility of up to two additional sites yet to be selected. The LCOGT education and public outreach effort is transforming into a "Citizen Science" program. Several projects will encompass taking observations through the network, analyzing the data, and sharing the results with other citizen scientists from around the world. The first of these projects, "Agent Exoplanet," will be launched in mid-2011, and will involve analyzing brand-new data to create a light curve of an exoplanet. As the network is not yet complete, this test project will not include actual observing as future ones will. More information about LCOGT and its Citizen Science program can be found online (http://www.lcogt.net). In addition to material to get started in the Citizen Science program, the website also includes resources and content for more hands-on activities using archived data, general astronomy pages, network information, complete access to the public data archive, current news, and recent publications. And don't forget to

  16. Archaeological Sites Inventory of the Training Area 10 and 12 Portions of the Pinon Canyon Maneuver Site, Las Animas County, Colorado. Volume 1

    DTIC Science & Technology

    2004-01-01

    Las Cruces, New Mexico Fort Carson Cultural Resources Management Series 17S Contribution Number 10 This project was prepared for and funded by the...National Park Service, Lincoln, Nebraska Cooperative Agreement No. 1443-CA-6000-98-016 Prepared by The Department of Sociology and Anthropology New Mexico ...State University Las Cruces, New Mexico NATIONALS IL WE Fort Carson Cultural Resources Management Series Contribution Number 10 This project was

  17. Morphology and mechanics of large collapses: Sotano de las Golondrinas, Mexico

    NASA Astrophysics Data System (ADS)

    Lauritzen, S.-E.; Hammer, Ø.; Wheeler, W.; Redfield, T.; Blanco, M.; Rosales Lagarde, L.; Jamtveit, B.

    2012-04-01

    The dynamics and mode of formation of large karst pipes are not yet fully understood. We present precise Lidar and structural field data of the 340+ m deep open karst shaft el Sotano de las Golondrinas, and test the geometry on a a simplified 2D evolution model. The Golondrinas shaft is located in the San Luis county, northeastern México and is developed in massive, early cretaceous (Barremian-Coniacian) reef- limestones (El Abra/ El Doctor fm.). It is a bell-shaped breakout dome that has reached the land surface, i.e. a classical Einstrurtzdoline. The dimensions and shape makes it to an interesting case study, as it has similar dimensions as breccia-pipes encountered in many paleokarsts, but is incompletely filled, so that internal structure can be easily inspected. Second, with regard to stress mechanisms controlling roof collapse, the large dimensions (270 - 130 m diameter at the base) reduce the influence (anisotropy) of geological structures in comparison to smaller pipes (e.g. <70 m diameter). We may thus test morphology against the shape of various tectonic and gravitational stress distributions. During our field campaign in 2009, it was decided to re-map the cavity using laser (Lidar and rangefinders) in order to obtain exact dimensions and high-resolution images of morphology and geologic structure. The maximum explored depth is a fissure at -512 m with the main floor between 325 and 400 meters below the skylight entrance of 80 m diameter. Overall, the shaft is cigar-shaped and oval in outline. Its horizontal length/width ratio at floor level is about 2.31, with an azimuth of elongation of about 125 degrees true. The shaft is developed along a major, steep fracture zone (115°, true) which makes up the north wall. The fracture has no detectable off-set, in all very few faults were observed. The strike of the guiding fracture, the azimuth of elongation and the direction of the least horizontal stress direction (111°, true) coincide. Where it occurs

  18. Xenoliths of Cerro las Mercedes, Costa Rica: a Geochemical Record of Arc History?

    NASA Astrophysics Data System (ADS)

    Lindsay, F. N.; Gazel, E.; Herzberg, C. T.; Carr, M. J.; Feigenson, M. D.

    2006-12-01

    Over 70 ultramafic xenoliths, many with diameters of at least 3cm, open a window into the mantle beneath Cerro las Mercedes, Costa Rica. This quaternary vent is 70km behind the active volcanic front and near the northern boundary of the Caribbean Plateau. Both xenoliths and host lava remain well preserved in spite of substantial soil development in a rain forest environment. We analyzed the host lava and a subset of 30 rocks for bulk and mineral chemistry, which include both peridotite and pyroxenite populations. The host rock is Plio-Quaternary potassic alkaline basalt; depleted in SiO2 and Al2O3 and enriched in MgO and P2O5 relative to both present day and Miocene volcanics. In terms of trace elements, the host basalt has enriched LREEs and relative depletion of HFSEs, typical of island-arc basalt, both present and past. The coarse-grained pyroxenites have trace element chemistry akin to the volcanic front lavas of Costa Rica, although they are closer to chondritic values. Truly, they are more similar to basalts from Sarapiquí Miocene arc than to present day volcanic front basalts. Although there is enrichment in incompatible elements such as Ba and U and depletions in HFSEs, common in island arc basalts, the pyroxenites have a strong positive Pb anomaly that is characteristic only of the Miocene arc, not present day lavas. We interpret the pyroxenites as cumulates. The peridotite population includes dunites, spinel lherzolites and lherzolites. These rocks have Mg-numbers ranging from 87 to 92 and Cr-numbers ranging from 6 to 61. Whole rock geochemistry indicates that the peridotite xenoliths are fragments of mantle associated with the western Caribbean Plateau. SiO2, FeO, Al2O3 and MgO contents of several Cerro Mercedes peridotites are similar to those expected of hot residues that would form in a plume environment. Trace elements reveal some samples with enrichment of Ba and U, and depletion in Nb and Ta indicating variable extents of melt-rock reaction and

  19. Laser Remote Measurements of atmospheric pollutants (Las-R-Map): UV-Visible Laser system description and data processing

    NASA Astrophysics Data System (ADS)

    Sivakumar, V.; Wyk, H. V.

    Laser radar more popularly known as LIDAR LIght Detection And Ranging is becoming one of the most powerful techniques for active remote sensing of the earth s atmosphere Around the globe several new lidar systems have been developed based on the scientific interest Particularly the DIfferential Absorption Lidar DIAL technique is only one which can provide the better accuracy of measuring atmospheric pollutants Using modern advanced techniques and instrumentation a mobile DIAL system called laser remote measurements of atmospheric pollutants hear after referred as Las-R-Map is designed at National Laser Centre NLC --Pretoria 25 r 45 prime S 28 r 17 prime E Las-R-Map is basically used for measuring atmospheric pollutants applying the principle of absorption by constituents The system designed primarily to focus on the following pollutant measurements such as SO 2 CH 4 CO 2 NO 2 and O 3 In future the system could be used to measure few particulate matter between 2 5 mu m and 10 mu m Benzene Hg 1 3-butadiene H 2 S HF and Volatile Organic Compounds VOC Las-R-map comprises of two different laser sources Alexandrite and CO 2 optical receiver data acquisition and signal processor It uses alexandrite laser in the UV-Visible region from 200 nm to 800 nm and CO 2 laser in the Far-IR region from 9 2 mu m to 10 8 mu m Such two different laser sources make feasibility for studying the wide range of atmospheric pollutants The present paper is focused on technical details

  20. Distress in the Desert: Neighborhood Disorder, Resident Satisfaction, and Quality of Life during the Las Vegas Foreclosure Crisis.

    PubMed

    Batson, Christie D; Monnat, Shannon M

    2015-03-01

    Using surveys collected from a sample of households nested within 'naturally occurring' neighborhoods in Las Vegas, NV during the 2007-2009 economic recession, this study examines the associations between real and perceived measures of neighborhood distress (foreclosure rate, physical decay, crime) and residents' reports of neighborhood quality of life and neighborhood satisfaction. Consistent with social disorganization theory, both real and perceived measures of neighborhood disorder were negatively associated with quality of life and neighborhood satisfaction. Residents' perceptions of neighborliness partially acted as a buffer against the effects of neighborhood distress, including housing foreclosures, on quality of life and neighborhood satisfaction.

  1. Hydrostratigraphic Framework of the Raton, Vermejo, and Trinidad Aquifers in the Raton Basin, Las Animas County, Colorado

    USGS Publications Warehouse

    Watts, Kenneth R.

    2006-01-01

    Exploration for and production of coalbed methane has increased substantially in the Rocky Mountain region of the United States since the 1990s. During 1999-2004, annual production of natural gas (coalbed methane) from the Raton Basin in Las Animas County, Colorado, increased from 28,129,515 to 80,224,130 thousand cubic feet, and the annual volume of ground water coproduced by coalbed methane wells increased from about 949 million gallons to about 2,879 million gallons. Better definition of the hydrostratigraphic framework of the Raton, Vermejo, and Trinidad aquifers in the Raton Basin of southern Colorado is needed to evaluate the long-term effects of coalbed methane development on the availability and sustainability of ground-water resources. In 2001, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began a study to evaluate the hydrogeology of the Raton Basin in Huerfano and Las Animas Counties, Colorado. Geostatistical methods were used to map the altitude of and depths to the bottoms and tops (structure) and the apparent thicknesses of the Trinidad Sandstone, the Vermejo Formation, and the Raton Formation in Las Animas County, based on completion reports and drillers' logs from about 1,400 coalbed methane wells in the Raton Basin. There was not enough subsurface control to map the structural surfaces and apparent thicknesses of the aquifers in Huerfano County. Geostatistical methods also were used to map the regional water table in the northern part of Las Animas County, based on reported depth to water from completion reports of water-supply wells. Although these maps were developed to better define the hydrostratigraphic framework, they also can be used to determine the contributing aquifer(s) of existing water wells and to estimate drilling depths of proposed water wells. These maps of the hydrostratigraphic framework could be improved with the addition of measured sections and mapping of geologic contacts at outcrops

  2. Las líneas de aluminio neutro como diagnóstico cromosférico

    NASA Astrophysics Data System (ADS)

    Fernández Borda, R.; Mauas, P. J. D.

    Se presenta un modelo atómico para el cálculo de las lí neas del Aluminio neutro que se forman en la cromósfera solar. En particular, se estudia la línea λ 3961 Å, que, por estar muy próxima a la lí nea H del Ca II y a Hɛ es muy frecuentemente observada. Observaciones en esta lí nea obtenidas con el espectrógrafo a instalarse en el CASLEO, serán utilizadas para el estudio de fulguraciones solares.

  3. Algorithms and Software for Solving Coupled Discrete-Time Riccati Equations Via the L-A-S Language.

    DTIC Science & Technology

    1986-08-01

    1982 . 7THESIS Submitted in partial fulfillment of the requirements 4 for the degree of Doctor of Philosophy in Electrical Engineering in the Graduate...TIME RICCATI EQUATIONS VIA THE L-A-S LANGUAGE Phillip James West, Ph.D. Department of Electrical and Computer Engineering University of Illinois at...the proof may be found in Appendix B. Theorem 3.2 : Lipschitz Constants for the Feedbacks Given(X.Y).(Z.W) E A.then IIB,(F2 (Z.W)-F(X.Y))1 2 a 2 11X-Z

  4. Distress in the Desert: Neighborhood Disorder, Resident Satisfaction, and Quality of Life during the Las Vegas Foreclosure Crisis

    PubMed Central

    Batson, Christie D.; Monnat, Shannon M.

    2014-01-01

    Using surveys collected from a sample of households nested within ‘naturally occurring’ neighborhoods in Las Vegas, NV during the 2007-2009 economic recession, this study examines the associations between real and perceived measures of neighborhood distress (foreclosure rate, physical decay, crime) and residents' reports of neighborhood quality of life and neighborhood satisfaction. Consistent with social disorganization theory, both real and perceived measures of neighborhood disorder were negatively associated with quality of life and neighborhood satisfaction. Residents' perceptions of neighborliness partially acted as a buffer against the effects of neighborhood distress, including housing foreclosures, on quality of life and neighborhood satisfaction. PMID:25750507

  5. Hacia el consumo informado de tabaco en México: efecto de las advertencias con pictogramas en población fumadora

    PubMed Central

    Thrasher, James F; Pérez-Hernández, Rosaura; Arillo-Santillán, Edna; Barrientos-Gutiérrez, Inti

    2015-01-01

    Resumen Objetivo Evaluar el efecto de las advertencias sanitarias (AS) con pictogramas en las cajetillas de tabaco en adultos fumadores. Material y métodos Cohorte de fumadores con representatividad poblacional de siete ciudades mexi canas, antes (2010) y después (2011) de la implementación de AS con pictogramas (ASP). Para determinar el cambio en las variables sobre el impacto cognitivo y conductual de las advertencias, se estimaron modelos bivariados y ajustados de ecuaciones de estimación generalizada. En el Segundo levantamiento (2011), se estimaron modelos para determiner los factores que se asocian con el reporte de recordar cada advertencia que había entrado al mercado, además de los factores asociados con el autorreporte del impacto de cada advertencia vigente. Resultados Se observaron incrementos importantes de 2010 a 2011 en los conocimientos sobre los riesgos de fumar, los componentes tóxicos del tabaco y el número telefónico para recibir consejos sobre dejar de fumar. La recordación e impacto de las primeras advertencias con pictogramas parecen ser amplios y equitativos a través de la población fumadora. En comparación con 2010, un mayor nivel de ex fumadores entrevistados en 2011 reportaron que las advertencias habían influido mucho en dejar de fumar (RM=2.44, 95% IC 1.27–4.72). Conclusiones Las AS con pictogramas han logrado un impacto importante en el conocimiento y conducta, información relevante para la población y en tomadores de decisiones. PMID:22689162

  6. Subsurface Connections and Magma Mixing as revealed by Olivine- and Pyroxene-Hosted Melt Inclusions from Cerro Negro Volcano and the Las Pilas-El Hoyo Complex, Nicaragua.

    NASA Astrophysics Data System (ADS)

    Venugopal, S.; Moune, S.; Williams-Jones, G.

    2015-12-01

    Cerro Negro, the youngest volcano in the Central American Volcanic Belt, is a polygenetic cinder cone with relatively frequent explosive basaltic eruptions. Las Pilas, on the other hand, is a much larger and older complex with milder and less frequent eruptions. Based on historical data, these two closely spaced volcanoes have shown concurrent eruptive behavior, suggesting a subsurface connection. To further investigate this link, melt inclusions, which are blebs of melt trapped in growing crystals, were the obvious choice for optimal comparison of sources and determination of pre-eruptive volatile contents and magmatic conditions. Olivine-hosted inclusions were chosen for both volcanoes and pyroxene-hosted inclusions were also sampled from Las Pilas to represent the evolved melt. Major, volatile and trace elements reveal a distinct geochemical continuum with Cerro Negro defining the primitive end member and Las Pilas representing the evolved end member. Volatile contents are high for Cerro Negro (up to 1260 ppm CO2, 4.27 wt% H2O and 1700 ppm S) suggesting that volatile exsolution is likely the trigger for Cerro Negro's explosive eruptions. Las Pilas volatile contents are lower but consistent with degassing and evolutionary trends shown by major oxides. Trace element contents are rather unique and suggest Cerro Negro magmas fractionally crystallize while Las Pilas magmas are the products of mixing. Magmatic conditions were estimated with major and volatile contents: at least 2.4 kbar and 1170 °C for Cerro Negro melts and 1.3 kbar and 1130 °C for Las Pilas melts with an overall oxygen fugacity at the NNO buffer. In combination with available literature data, this study suggests an interconnected subsurface plumbing system and thus Cerro Negro should be considered as the newest vent within the Las Pilas-El Hoyo Complex.

  7. Novel inhibitors of the Pseudomonas aeruginosa virulence factor LasB: a potential therapeutic approach for the attenuation of virulence mechanisms in pseudomonal infection.

    PubMed

    Cathcart, George R A; Quinn, Derek; Greer, Brett; Harriott, Pat; Lynas, John F; Gilmore, Brendan F; Walker, Brian

    2011-06-01

    Pseudomonas elastase (LasB), a metalloprotease virulence factor, is known to play a pivotal role in pseudomonal infection. LasB is secreted at the site of infection, where it exerts a proteolytic action that spans from broad tissue destruction to subtle action on components of the host immune system. The former enhances invasiveness by liberating nutrients for continued growth, while the latter exerts an immunomodulatory effect, manipulating the normal immune response. In addition to the extracellular effects of secreted LasB, it also acts within the bacterial cell to trigger the intracellular pathway that initiates growth as a bacterial biofilm. The key role of LasB in pseudomonal virulence makes it a potential target for the development of an inhibitor as an antimicrobial agent. The concept of inhibition of virulence is a recently established antimicrobial strategy, and such agents have been termed "second-generation" antibiotics. This approach holds promise in that it seeks to attenuate virulence processes without bactericidal action and, hence, without selection pressure for the emergence of resistant strains. A potent inhibitor of LasB, N-mercaptoacetyl-Phe-Tyr-amide (K(i) = 41 nM) has been developed, and its ability to block these virulence processes has been assessed. It has been demonstrated that thes compound can completely block the action of LasB on protein targets that are instrumental in biofilm formation and immunomodulation. The novel LasB inhibitor has also been employed in bacterial-cell-based assays, to reduce the growth of pseudomonal biofilms, and to eradicate biofilm completely when used in combination with conventional antibiotics.

  8. Long-term assessment of the oil spill at Bahia Las Minas, Panama. Interim report. Volume 1: Executive summary

    SciTech Connect

    Keller, B.D.; Jackson, J.B.C.

    1991-10-01

    On April 27, 1986, at least 8 million liters of medium-weight crude oil spilled from a ruptured storage tank into the Bahia Las Minas on the Caribbean Coast of Panama. Coral reefs, seagrass communities, and mangroves were affected. The area of the spill was also the location of the Smithsonian Tropical Research Institute's Galeta Laboratory where resident and visiting scientists have been studying the ecology of the Bahia Las Minas and the adjacent areas for over 15 years. Because this was a unique opportunity to assess the immediate biological effects following a major spill in the Caribbean region and to monitor the subsequent recovery, the U.S. Department of the Interior Minerals Management Service supported a 5-year environmental study. The objectives of the study are to identify any long-term changes in the marine environment that may have resulted from the spill and to understand the ecological processes causing such changes. This is the first report from the study and addresses the effects observed during the first two years of the effort.

  9. Long-term assessment of the oil spill at Bahia Las Minas, Panama. Interim report. Volume 2: Technical report

    SciTech Connect

    Keller, B.D.; Jackson, J.B.C.

    1991-10-01

    On April 27, 1986, at least 8 million liters of medium-weight crude oil spilled from a ruptured storage tank into the Bahia Las Minas on the Caribbean Coast of Panama. Coral reefs, seagrass communities, and mangroves were affected. The area of the spill was also the location of the Smithsonian Tropical Research Institute's Galeta Laboratory where resident and visiting scientists have been studying the ecology of the Bahia Las Minas and the adjacent areas for over 15 years. Because this was a unique opportunity to assess the immediate biological effects following a major spill in the Caribbean region and to monitor the subsequent recovery, the U.S. Department of the Interior Minerals Management Service supported a 5-year environmental study. The objectives of the study are to identify any long-term changes in the marine environment that may have resulted from the spill and to understand the ecological processes causing such changes. This is the first report from the study and addresses the effects observed during the first two years of the effort.

  10. An analysis of urban thermal characteristics and associated land cover in Tampa Bay and Las Vegas using Landsat satellite data

    USGS Publications Warehouse

    Xian, George; Crane, Mike

    2006-01-01

    Remote sensing data from both Landsat 5 and Landsat 7 systems were utilized to assess urban area thermal characteristics in Tampa Bay watershed of west-central Florida, and the Las Vegas valley of southern Nevada. To quantitatively determine urban land use extents and development densities, sub-pixel impervious surface areas were mapped for both areas. The urban–rural boundaries and urban development densities were defined by selecting certain imperviousness threshold values and Landsat thermal bands were used to investigate urban surface thermal patterns. Analysis results suggest that urban surface thermal characteristics and patterns can be identified through qualitatively based urban land use and development density data. Results show the urban area of the Tampa Bay watershed has a daytime heating effect (heat-source), whereas the urban surface in Las Vegas has a daytime cooling effect (heat-sink). These thermal effects strongly correlated with urban development densities where higher percent imperviousness is usually associated with higher surface temperature. Using vegetation canopy coverage information, the spatial and temporal distributions of urban impervious surface and associated thermal characteristics are demonstrated to be very useful sources in quantifying urban land use, development intensity, and urban thermal patterns.

  11. Source study and tectonic implications of the historic 1958 Las Melosas crustal earthquake, Chile, compared to earthquake damage

    NASA Astrophysics Data System (ADS)

    Alvarado, Patricia; Barrientos, Sergio; Saez, Mauro; Astroza, Maximiliano; Beck, Susan

    2009-06-01

    The 4 September 1958 earthquake has been the largest event recorded at shallow depths in the western flank of the Andes on Chilean territory. New estimates of fault orientation, depth and size have been carried out using modern techniques of body-wave modeling. Two possible fault planes solutions with right-lateral displacement on an east-west fault or left-lateral displacement on a north-south fault nucleated at 5-9 km depth produce the best fit to teleseismic recordings. A seismic moment M0 of 0.227 × 10 19 N m associated with a moment-magnitude Mw of 6.3 has been estimated with these techniques, which is a more reliable estimation of earthquake size than the 0.4-0.7 units larger surface-wave magnitude Ms earlier reported. Although no surface rupture for the 1958 Las Melosas crustal earthquake was reported, the displacement along east-west structures like that one suggested for one of the fault plane in our focal mechanism solution seems to be an efficient mechanism to accommodate differences in shortening from north to south in the High Andean Cordillera. Reports on damage, landslide effects as well as re-analysis of intensities associated with the new seismic source estimations for the 1958 Las Melosas earthquake are presented to further estimate the hazard to which this zone, and others along the western foothills of the Andes, is exposed.

  12. Morphology, body proportions, and postcranial hypertrophy of a female Neandertal from the Sima de las Palomas, southeastern Spain

    PubMed Central

    Walker, Michael J.; Ortega, Jon; Parmová, Klara; López, Mariano V.; Trinkaus, Erik

    2011-01-01

    Considerations of Neandertal geographical variation have been hampered by the dearth of remains from Mediterranean Europe and the absence there of sufficiently complete associated postcrania. The 2006 and 2007 excavation of an articulated partial skeleton of a small adult female Neandertal at the Sima de las Palomas, Murcia, southeastern Spain (Sima de las Palomas 96) provides substantial and secure information on body proportions among southern European Neandertals, as well as further documenting the nature of Neandertal biology in southern Iberia. The remains exhibit a suite of cranial, mandibular, dental, and postcranial features, of both Neandertals and archaic Homo generally, that distinguish them from contemporary and subsequent early modern humans. Its lower limbs exhibit the robustness of later Pleistocene Homo generally, and its upper limbs conform to the pattern of elevated robustness of the Neandertals. Its body proportions, including relative clavicular length, distal limb segment lengths, and body mass to stature indicators, conform to the “cold-adapted” pattern of more northern Neandertals. Palomas 96 therefore documents the presence of a suite of “Neandertal” characteristics in southern Iberia and, along with its small body size, the more “Arctic” body proportions of other European Neandertals despite the warmer climate of southern Iberia during marine isotope stage 3. PMID:21646528

  13. Morphology, body proportions, and postcranial hypertrophy of a female Neandertal from the Sima de las Palomas, southeastern Spain.

    PubMed

    Walker, Michael J; Ortega, Jon; Parmová, Klara; López, Mariano V; Trinkaus, Erik

    2011-06-21

    Considerations of Neandertal geographical variation have been hampered by the dearth of remains from Mediterranean Europe and the absence there of sufficiently complete associated postcrania. The 2006 and 2007 excavation of an articulated partial skeleton of a small adult female Neandertal at the Sima de las Palomas, Murcia, southeastern Spain (Sima de las Palomas 96) provides substantial and secure information on body proportions among southern European Neandertals, as well as further documenting the nature of Neandertal biology in southern Iberia. The remains exhibit a suite of cranial, mandibular, dental, and postcranial features, of both Neandertals and archaic Homo generally, that distinguish them from contemporary and subsequent early modern humans. Its lower limbs exhibit the robustness of later Pleistocene Homo generally, and its upper limbs conform to the pattern of elevated robustness of the Neandertals. Its body proportions, including relative clavicular length, distal limb segment lengths, and body mass to stature indicators, conform to the "cold-adapted" pattern of more northern Neandertals. Palomas 96 therefore documents the presence of a suite of "Neandertal" characteristics in southern Iberia and, along with its small body size, the more "Arctic" body proportions of other European Neandertals despite the warmer climate of southern Iberia during marine isotope stage 3.

  14. An evaluation of lead contamination in plastic toys collected from day care centers in the Las Vegas Valley, Nevada, USA.

    PubMed

    Greenway, Joseph A; Gerstenberger, Shawn

    2010-10-01

    Childhood exposure to environmental lead continues to be a major health concern. This study examined lead content within the plastic of children's toys collected from licensed day care centers in the Las Vegas valley, Nevada. It was hypothesized that the use of lead as a plastics stabilizer would result in elevated lead (≥600 ppm) in polyvinyl chloride plastics (PVC) compared to non-PVC plastics. It was also hypothesized that, due to the use of lead chromate as a coloring agent, yellow toys would contain higher concentrations of lead (≥600 ppm) than toys of other colors. Toy samples were limited to those found in day care centers in Las Vegas, Nevada. 10 day care centers were visited and approximately 50 toy samples were taken from each center. Of the 535 toys tested, 29 contained lead in excess of 600 parts per million (ppm). Of those 29 toys, 20 were PVC and 17 were yellow. Both of the two hypotheses were strongly supported by the data.

  15. Interaction of a cationic gemini surfactant with DNA and with sodium poly(styrene sulphonate) at the air/water interface: a neutron reflectometry study.

    PubMed

    Vongsetskul, T; Taylor, D J F; Zhang, J; Li, P X; Thomas, R K; Penfold, J

    2009-04-07

    The interactions between a dicationic gemini surfactant with a six-hydrocarbon spacer (1,2-bis(dodecyldimethyl-ammonio)hexane dibromide, C12C6C12Br2) and anionic polyelectrolyte DNA or sodium (polystyrene sulfonate) (NaPSS) at the air/solution interface have been studied and compared using neutron reflectometry together with surface tension. In the presence of the dichained cationic gemini surfactant, DNA and NaPSS display very different adsorption behaviors. The DNA/gemini mixtures show adsorption behavior very similar to that of DNA/C12TAB mixtures, with enhanced surfactant adsorption at low concentrations and thick structured layers at higher concentrations. However, for the NaPSS/gemini mixtures the amount of gemini at the surface is reduced relative to that in the absence of NaPSS at concentrations below the cmc. These differences in adsorption behavior are attributed to differences in the molecular structure and flexibility of the two polyanions. NaPSS is relatively hydrophobic and flexible enough to form bulk-phase polymer-micelle complexes with the gemini surfactant at low surfactant concentrations, whereas the adsorption of surface complexes is much less favorable because the dications on the gemini would require adjacent bulky pendant charges on the NaPSS to be oriented toward the surface. This would force the NaPSS to bend significantly whereas it is more favorable for the NaPSS to adopt an extended conformation at the surface. Thus, surfactant is actually removed from the surface to form bulk-phase complexes. In contrast with NaPSS, DNA has a far more rigid structure, and the charges on the backbone are at fixed intervals, factors that make the formation of surface DNA-monomer complexes much more favorable than bulk-phase DNA-micelle complexes. Finally, a short-chain sample of NaPSS consisting of only five to six segments adsorbs very strongly at the surface with the gemini to form more extensive layered structures than have previously been observed, consisting of approximately five sublayers.

  16. A sulphonated carbon dot-chitosan hybrid hydrogel nanocomposite as an efficient ion-exchange film for Ca2+ and Mg2+ removal

    NASA Astrophysics Data System (ADS)

    Baruah, Upama; Konwar, Achyut; Chowdhury, Devasish

    2016-04-01

    We have developed a hybrid hydrogel nanocomposite film via conjugation of oxidised carbon dots synthesized from 11-mercaptoundecanoic acid with chitosan. The potential applicability of the film was then successfully tested for the removal of Ca2+ and Mg2+ ions from solution.We have developed a hybrid hydrogel nanocomposite film via conjugation of oxidised carbon dots synthesized from 11-mercaptoundecanoic acid with chitosan. The potential applicability of the film was then successfully tested for the removal of Ca2+ and Mg2+ ions from solution. Electronic supplementary information (ESI) available: The ESI includes the detailed synthesis and characterization of carbon dots both before and after oxidation and of the carbon dot-chitosan nanocomposite films viz. DLS, SEM, UV-visible, FTIR, PL spectroscopy and TGA. See DOI: 10.1039/c6nr01129b

  17. Synthesis, characterization and fuel cell performance tests of boric acid and boron phosphate doped, sulphonated and phosphonated poly(vinyl alcohol) based composite membranes

    NASA Astrophysics Data System (ADS)

    Şahin, Alpay; Ar, İrfan

    2015-08-01

    The aim of this study is to synthesize a composite membrane having high proton conductivity, ion exchange capacity and chemical stability. In order to achieve this aim, poly(vinyl alcohol) (PVA) based composite membranes are synthesized by using classic sol-gel method. Boric acid (H3BO3) and boron phosphate (BPO4) are added to the membrane matrix in different ratios in order to enhance the membrane properties. Characterization tests, i.e; FT-IR analysis, mechanical strength tests, water hold-up capacities, swelling properties, ion exchange capacities, proton conductivities and fuel cell performance tests of synthesized membranes are carried out. As a result of performance experiments highest performance values are obtained for the membrane containing 15% boron phosphate at 0.6 V and 750 mA/cm2. Water hold-up capacity, swelling ratio, ion exchange capacity and proton conductivity of this membrane are found as 56%, 8%, 1.36 meq/g and 0.37 S/cm, respectively. These values are close to the values obtained ones for perfluorosulphonic acid membranes. Therefore this membrane can be regarded as a promising candidate for usage in fuel cells.

  18. Utility of RAPD marker for genetic diversity analysis in gamma rays and ethyl methane sulphonate (EMS)-treated Jatropha curcas plants.

    PubMed

    Dhakshanamoorthy, Dharman; Selvaraj, Radhakrishnan; Chidambaram, Alagappan

    2015-02-01

    The presence of important chemical and physical properties in Jatropha curcas makes it a valuable raw material for numerous industrial applications, including the production of biofuel. Hence, the researcher's interest is diversified to develop more and better varieties with outstanding agronomic characteristics using conventional breeding. Among these, mutation breeding is one of the best approaches to bring genetic changes in plant species. The aim of this study is to evaluate the diversity and genetic relationship among J. curcas mutants, which were obtained from different doses of gamma rays (control, 5 Kr, 10 Kr, 15 Kr, 20 Kr and 25 Kr) and EMS (1%, 2%, 3% and 4%), using RAPD marker. Among the 21 random primers, 20 produced polymorphic bands. The primers, OPM-14 and OPAW-13, produced a minimum number of bands (3) each across the ten mutants, while the primer OPF-13 produced the maximum number of bands (10), followed by the primers OPU-13, OPAM-06, OPAW-09 and OPD-05, which produced 9 bands each. The number of amplicons varied from 3 to 10, with an average of 7 bands, out of which 4.57 were polymorphic. The percentage of polymorphism ranged from 0.00 to 100 with an average of 57%. In the present study, RAPD markers were found most polymorphic, with an average polymorphism information content (PIC) value of 0.347, effective multiplex ratio (EMR) of 35.14, marker index (MI) of 14.19, resolution power (Rp) of 11.19, effective marker index (EMI) of 8.21 and genotype index (GI) of 0.36, indicating that random primers are useful in studies of genetic characterization in J. curcas mutant plants. In a dendrogram constructed based on Jaccard's similarity coefficients, the mutants were grouped into three main clusters viz., (a) control, 10 Kr, 15 Kr, 20 Kr, 2% EMS, and 3% EMS, (b) 5 Kr and 1% EMS, and (c) 25 Kr and 4% EMS mutants. Based on the attributes of the random primers and polymorphism studied, it is concluded that RAPD analysis offers a useful molecular marker for the identification of the mutants in gamma rays and EMS treated plants.

  19. Determination of anionic surface active agents using silica coated magnetite nanoparticles modified with cationic surfactant aggregates.

    PubMed

    Pena-Pereira, Francisco; Duarte, Regina M B O; Trindade, Tito; Duarte, Armando C

    2013-07-19

    The development of a novel methodology for extraction and preconcentration of the most commonly used anionic surface active agents (SAAs), linear alkylbenzene sulfonates (LAS), is presented herein. The present method, based on the use of silica-magnetite nanoparticles modified with cationic surfactant aggregates, was developed for determination of C10-C13 LAS homologues. The proposed methodology allowed quantitative recoveries of C10-C13 LAS homologues by using a reduced amount of magnetic nanoparticles. Limits of detection were in the range 0.8-1.9μgL(-1) for C10-C13 LAS homologues, while the repeatability, expressed as relative standard deviation (RSD), ranged from 2.0 to 3.9% (N=6). Finally, the proposed method was successfully applied to the analysis of a variety of natural water samples.

  20. 2LAs, 3LAs, and the enterprise

    SciTech Connect

    Hoffmann, T.

    1998-01-01

    This article is about new things that engineers, facility managers and automation system operators need to learn about and understand when it comes to integrating information throughout an enterprise. The goal is to help one better understand the connection between building systems and building intelligence. The authors set the foundation with an overview of the latest concept in network communications, enterprise computing. Because any new technology spawns a number of acronyms, they`ll also investigate new two-, three-, four- and five-letter acronyms that directly affect the changing role of the building automation system (BAS) as it becomes an integral, contributing part of the business. In each case, one or more Internet URLs will be provided for more information.

  1. Establishment and characterization of a novel lymphangiosarcoma cell line (MO-LAS) compared with the hemangiosarcoma cell line (ISO-HAS).

    PubMed

    Masuzawa, Mikio; Masuzawa, Mamiko; Hamada, Yuhko; Arakawa, Nobuko; Mori, Mari; Ishii, Masako; Nishiyama, Shigeo

    2012-08-01

    The concept of "lymphangiosarcoma" remains obscure. Therefore, we reported a patient with lymphangiosarcoma, resistant to immunotherapy. The patient presented with impressive and discriminative features: clinically an ill-defined edematous lesion with lymphorrhea and pathologically atypical vascular channel formation without extravasation of blood, clearly distinguished from common angiosarcoma with hemorrhage. From this case, a lymphangiosarcoma cell line, MO-LAS, was established and its characteristics were compared with the hemangiosarcoma cell line, ISO-HAS. Flow cytometric analysis revealed that MO-LAS was negative for factor VIII-related antigen, but positive for CD31, D2-40, NZ-1, and vascular endothelial growth factor receptor-3 (VEGFR-3), similar to ISO-HAS. However, MO-LAS expressed a much higher level of homeobox gene PROX1, indicating a lymphatic phenotype, compared with ISO-HAS. Furthermore, MO-LAS showed a much lesser expression of oncogenes and much lower sensitivity against lymphokine-activated killer (LAK) cells. Lymphangiosarcoma may be difficult to recognize by the immune system. Conclusively, the establishment of MO-LAS, a novel angiosarcoma cell line bearing lymphatic characters, strongly suggests the entity of lymphangiosarcoma.

  2. [Effects and mechanisms of inorganic anions in water on degradation of LAS by UV/H2 O2 combination process].

    PubMed

    Pan, Jing; Sun, Tie-Heng; Li, Hai-Bo

    2007-11-01

    Experiments are carried out to study the effects and mechanisms of inorganic anions in water on the degradation of linear alkyl benzene sulfonate (LAS) in UV/H2 O2 process. The results show that UV/H2 O2 process could remove LAS effectively, and the rate of photodegradation follows first-order reaction kinetics model. Under the condition that H2 O2 concentration was 8 mg x L(-1) and a 14 W low pressure mercury vapor discharge lamp irradiated samples, the first-order photodegradation rate constant of LAS in distilled water and tap water were 0.018 0 min(-1) and 0.012 2 min(-1) respectively. NO3-, Cl-, SO4(2-) and HCO3- have inhibitory action on LAS photodegradation. The higher inorganic anions concentration was, the stronger inhibitory action. When their concentrations were 5, 10 and 15 mmol x L(-1) respectively, their inhibitory action order was HCO3- > NO3- > Cl- > SO4(2-) all the time. It was anions synthetical effect that caused photodegradation rate constant of LAS in tap water lower than distilled water.

  3. Water-quality data for the Rio Grande between Picacho Bridge near Las Cruces and Calle del Norte Bridge near Mesilla, New Mexico, 1996-97

    USGS Publications Warehouse

    Huff, G.F.

    1998-01-01

    The City of Las Cruces is concerned about water quality in a reach of the Rio Grande that receives outfall from the City of Las Cruces wastewater-treatment plant. Water-quality samples were collected from the Rio Grande at Picacho Bridge near Las Cruces, New Mexico; from the sampling site at the City of Las Cruces wastewater-treatment plant; and from the Rio Grande at Calle del Norte Bridge near Mesilla, New Mexico. The samples were collected on 12 days from August 6, 1996, to February 28, 1997, and were analyzed for a suite of dissolved and total constituents including trace metals. Instantaneous stream discharge was measured concurrently with collection of the Rio Grande samples. At the wastewater- treatment plant, the City of Las Cruces provided instantaneous discharge rates concurrent with sampling. Quality-control measures used in this study to ensure analytical accuracy included replicate sampling, replicate analysis of split samples, ambient blanks, equipment blanks, and analysis of standard reference water samples.

  4. Log ASCII Standard (LAS) Files for Geophysical Wireline Well Logs and Their Application to Geologic Cross Sections Through the Central Appalachian Basin

    USGS Publications Warehouse

    Crangle, Robert D.

    2007-01-01

    Introduction The U.S. Geological Survey (USGS) uses geophysical wireline well logs for a variety of purposes, including stratigraphic correlation (Hettinger, 2001, Ryder, 2002), petroleum reservoir analyses (Nelson and Bird, 2005), aquifer studies (Balch, 1988), and synthetic seismic profiles (Kulander and Ryder, 2005). Commonly, well logs are easier to visualize, manipulate, and interpret when available in a digital format. In recent geologic cross sections E-E' and D-D', constructed through the central Appalachian basin (Ryder, Swezey, and others, in press; Ryder, Crangle, and others, in press), gamma ray well log traces and lithologic logs were used to correlate key stratigraphic intervals (Fig. 1). The stratigraphy and structure of the cross sections are illustrated through the use of graphical software applications (e.g., Adobe Illustrator). The gamma ray traces were digitized in Neuralog (proprietary software) from paper well logs and converted to a Log ASCII Standard (LAS) format. Once converted, the LAS files were transformed to images through an LAS-reader application (e.g., GeoGraphix Prizm) and then overlain in positions adjacent to well locations, used for stratigraphic control, on each cross section. This report summarizes the procedures used to convert paper logs to a digital LAS format using a third-party software application, Neuralog. Included in this report are LAS files for sixteen wells used in geologic cross section E-E' (Table 1) and thirteen wells used in geologic cross section D-D' (Table 2).

  5. Aerosol Light Absorption and Scattering at Four Sites in and Near Mexico City: Comparison with Las Vegas, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Arnott, W. P.; Miranda, G. P.; Gaffney, J. S.; Marley, N. A.

    2007-05-01

    Four photoacoustic spectrometers (PAS) for aerosol light scattering and absorption measurements were deployed in and near Mexico City in March 2006 as part of the Megacity Impacts on Regional and Global Environments (MIRAGE). The four sites included: an urban site at Instituto Mexicano del Petroleo (Mexican Oil Institute, denoted by IMP); a suburban site at the Technological University of Tecamac; a rural site at "La Biznaga" ranch; and a site at the Paseo de Cortes (altitude 3,810 meters ASL) in the rural area above Amecameca in the State of Mexico, on the saddle between the volcanoes Popocatepetl and Iztaccihuatl. A similar campaign was held in Las Vegas, Nevada, USA in January-February, 2003. The IMP site gave in-situ characterization of the Mexico City plume under favorable wind conditions while the other sites provided characterization of the plume, mixed in with any local sources. The second and third sites are north of Mexico City, and the fourth site is south. The PAS used at IMP operates at 532 nm, and conveniently allowed for characterization of gaseous absorption at this wavelength as well. Instruments at the second and third sites operate at 870 nm, and the one at the fourth site at 780 nm. Light scattering measurements are accomplished within the PAS by the reciprocal nephelometery method. In the urban site the aerosol absorption coefficient typically varies between 20 and 180 Mm-1 during the course of the day and significant diurnal variation of the aerosol single scattering albedo was observed probably as a consequence of secondary aerosol formation. Comparisons with TSI nephelometer scattering at the T0 site will be presented. We will present the diurnal variation of the scattering and absorption as well as the single scattering albedo and fraction of absorption due to gases at the IMP site and compare with Las Vegas diurnal variation. Mexico City 'breaths' more during the course of the day than Las Vegas, Nevada in part because the latitude of

  6. Changes in air quality at near-roadway schools after a major freeway expansion in Las Vegas, Nevada.

    PubMed

    Brown, Steven G; McCarthy, Michael C; DeWinter, Jennifer L; Vaughn, David L; Roberts, Paul T

    2014-09-01

    Near-roadway ambient black carbon (BC) and carbon monoxide (CO) concentrations were measured at two schools adjacent to a freeway and at an urban background school 2 km from the freeway to determine the change in concentrations attributable to vehicle emissions after the three-lane expansion of U.S. Highway 95 (US 95) in Las Vegas, Nevada. Between summer 2007 and summer 2008, average weekday small-vehicle volume increased by 40% +/- 2% (standard error). Average weekday large-vehicle volume decreased by 17% +/- 5%, due to a downturn in the economy and an associated decline in goods movement. Average vehicle speed increased from 58 to 69 mph, a 16% +/- 1% increase. The authors compared BC and CO concentrations in summer 2007 with those in summer 2008 to understand what effect the expansion of the freeway may have had on ambient concentrations: BC and CO were measured 17 m north of the freeway sound wall, CO was measured 20 m south of the sound wall, and BC was measured at an urban background site 2 km south of the freeway. Between summer 2007 and summer 2008, median BC decreased at the near-road site by 40% +/- 2% and also decreased at the urban background site by 24% +/- 4%, suggesting that much of the change was due to decreases in emissions throughout Las Vegas, rather than only on US 95. CO concentrations decreased by 14% +/- 2% and 10% +/- 3% at the two near-road sites. The decrease in BC concentrations after the expansion is likely due to the decrease in medium- and heavy-duty-vehicle traffic resulting from the economic recession. The decrease in CO concentrations may be a result of improved traffic flow, despite the increase in light-duty-vehicle traffic. Implications: Monitoring of BC and CO at near-road locations in Las Vegas demonstrated the impacts of changes in traffic volume and vehicle speed on near-road concentrations. However, urban-scale declines in concentrations were larger than near-road changes due to the impacts of the economic recession that

  7. Informe sobre el avance del proyecto de determinaciones de V sen i para todas las estrellas B más brillantes que 6.5 mag.

    NASA Astrophysics Data System (ADS)

    Abt, H.; Levato, H.

    Se ha finalizado con la determinación de V sen i para todas las estrellas B más brillantes que 6.5 mag y al norte de -30 grados de declinación. Esta muestra involucra casi 1000 estrellas. Las observaciones fueron realizadas desde KPNO. Mientras tanto, se ha completado desde CASLEO la observación de 350 estrellas B más brillantes que 6.5 mag. al sur de -30 grados. Además de la determinación de la rotación axial se determinan, en los casos posibles, los anchos equivalentes de las líneas 4471 Ådel He I y 4481 Ådel Mg II.

  8. Log ASCII Standard (LAS) Files for Geophysical (Gamma Ray) Wireline Well Logs and Their Application to Geologic Cross Section C-C' Through the Central Appalachian Basin

    USGS Publications Warehouse

    Trippi, Michael H.; Crangle, Robert D.

    2009-01-01

    U.S. Geological Survey (USGS) regional geologic cross section C-C' (Ryder and others, 2008) displays key stratigraphic intervals in the central Appalachian basin. For this cross section, strata were correlated by using descriptions of well cuttings and gamma ray well log traces. This report summarizes the procedures used to convert gamma ray curves on paper well logs to the digital Log ASCII (American Standard Code for Information Interchange) Standard (LAS) format using the third-party software application Neuralog. The procedures could be used with other geophysical wireline logs also. The creation of digital LAS files from paper well logs by using Neuralog is very helpful, especially when dealing with older logs with limited or nonexistent digital data. The LAS files from the gamma ray logs of 11 wells used to construct cross section C-C' are included in this report. They may be downloaded from the index page as a single ZIP file.

  9. Simulation of unsaturated flow and solute transport at the Las Cruces trench site using the PORFLO-3 computer code

    SciTech Connect

    Rockhold, M.L.; Wurstner, S.K.

    1991-03-01

    The objective of this work was to test the ability of the PORFLO-3 computer code to simulate water infiltration and solute transport in dry soils. Data from a field-scale unsaturated zone flow and transport experiment, conducted near Las Cruces, New Mexico, were used for model validation. A spatial moment analysis was used to provide a quantitative basis for comparing the mean simulated and observed flow behavior. The scope of this work was limited to two-dimensional simulations of the second experiment at the Las Cruces trench site. Three simulation cases are presented. The first case represents a uniform soil profile, with homogeneous, isotropic hydraulic and transport properties. The second and third cases represent single stochastic realizations of randomly heterogeneous hydraulic conductivity fields, generated from the cumulative probability distribution of the measured data. Two-dimensional simulations produced water content changes that matched the observed data reasonably well. Models that explicitly incorporated heterogeneous hydraulic conductivity fields reproduced the characteristics of the observed data somewhat better than a uniform, homogeneous model. Improved predictions of water content changes at specific spatial locations were obtained by adjusting the soil hydraulic properties. The results of this study should only be considered a qualitative validation of the PORFLO-3 code. However, the results of this study demonstrate the importance of site-specific data for model calibration. Applications of the code for waste management and remediation activities will require site-specific data for model calibration before defensible predictions of unsaturated flow and containment transport can be made. 23 refs., 16 figs., 3 tabs.

  10. An Intensity-Modulated CW LAS System for Application to ASCENDS: Overview of Development, Testing, and Evaluation

    NASA Astrophysics Data System (ADS)

    Ismail, S.; Harrison, F. W.; Dobler, J. T.; Browell, E. V.; Nehrir, A. R.; Lin, B.; Meadows, B.; Vanek, M. D.; Kooi, S. A.; Collins, J. E.; Refaat, T. F.; Yang, M. M.; Choi, Y.; DiJoseph, M.

    2012-12-01

    As part of the development of a capability for the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission NASA Langley Langley Research Center (LaRC) and ITT EXELIS are collaborating to develop and demonstrate an approach for measuring column CO2 from space. A Multi-Functional Fiber Laser Lidar (MFLL), a laser absorption spectrometer (LAS) system has been used to demonstrate high precision column CO2 measurements from aircraft platforms. MFLL operates near the 1.57 micron region using an intensity modulated CW LAS system. High precision column CO2 measurements have been demonstrated over several land and ocean surfaces under a variety of atmospheric conditions, and also demonstrated insensitivity to variations in surface reflectivity and altitude. Encoded modulation schemes have been used to minimize the influence of thin clouds on column CO2 measurements. We present examples of these measurements from past flight campaigns, and developments are presented on models to predict the precision and accuracy of these measurements as determined from ground-based range testing at LaRC during July-August 2012. We present a summary of results from testing of the MFLL from the ground using various targets at a distance of 860 m. During these tests measurements are made using well characterized ground targets, controlled background conditions, and a variety of intermediate range, partially reflecting and light attenuating targets that are used as simulants for thin clouds. A variety of modulation schemes are being tested to discriminate against cloud interferences and for evaluating precise ranging capability. Profiles of CO2, relative humidity (RH), pressure, and temperature along the range are being made to validate the CO2 column measurements. These ground-based measurements are valuable to validate models for predicting the precision and accuracy of these measurements, interpretation of measurements from aircraft by the MFLL, and projecting

  11. Systems dynamic model to forecast salinity load to the Colorado River due to urbanization within the Las Vegas Valley.

    PubMed

    Venkatesan, Arjun K; Ahmad, Sajjad; Johnson, Walter; Batista, Jacimaria R

    2011-06-01

    This study evaluates the impact of urban growth in the Las Vegas Valley (LVV), Nevada, USA on salinity of the Colorado River. In the past thirty eight years the LVV population has grown from 273,288 (1970) to 1,986,146 (2008). The wastewater effluents and runoff from the valley are diverted back to the Colorado River through the Las Vegas Wash (LVW). With the growth of the valley, the salinity released from urban areas has increased the level of TDS in the wastewater effluents, ultimately increasing the TDS in the Colorado River. The increased usage of water softeners in residential and commercial locations is a major contributor of TDS in the wastewater effluents. Controlling TDS release to the Colorado River is important because of the 1944 Treaty signed between the USA and Mexico. In addition, the agriculture salinity damage cost for the Colorado River has been estimated to be more than $306 a million per year using 2004 salinity levels. With the expected growth of LVV in coming years the TDS release into Lake Mead will increase over time. For this purpose, it is important to investigate future TDS release into the Colorado in anticipation of potential TDS reducing measures to be adopted. In this research, a dynamic simulation model was developed using system dynamics modeling to carry out water and TDS mass balances over the entire LVV. The dynamic model output agreed with historic data with an average error of 2%. Forecasts revealed that conservation efforts can reduce TDS load by 16% in the year 2035 when compared to the current trend. If total population using water softeners can be limited to 10% in the year 2035, from the current 30% usage, TDS load in the LVW can be reduced by 7%.

  12. Sources and concentrations of mercury and selenium in compartments within the Las Vegas Wash during a period of rapid change.

    PubMed

    Cizdziel, James; Zhou, Xiaoping

    2005-08-01

    The Las Vegas Wash, which drains the Las Vegas valley watershed and provides the second largest inflow to Lake Mead, is being dramatically altered with erosion control structures and wetland restoration efforts. The impact of these changes on the cycling and distribution of Hg and Se is of particular interest because of their tendency to bioaccumulate and because of a lack of information on these contaminants in the Wash. In this study, we determined concentrations of Hg and Se in surface water (monthly), groundwater (once) and sediments (quarterly) from strategic locations within and along the Wash during 2002 and 2003. The data was used to characterize Se sources and loading into the Wash. Samples containing resurfacing groundwater and urban runoff (LW10.75 and Duck Creek) had significantly higher yearly means (13.7 +/- 4.4 and 23.8 +/- 4.1 microg/L, respectively) compared with mainstream samples containing primarily treated wastewater (2.8 +/- 0.8 microg/L). Investigation of Se in tributaries, street runoff and rain suggest that the source of the elevated Se is likely groundwater seeps located within a relatively narrow geographic band on the southeast side of the valley. Se content of sediments was similar, except for LW10.75 which was rich in organic matter. Hg concentrations in the water and sediments were low, averaging 4 +/- 5 ng/L and 34 +/- 20 ng/g, dw, respectively. Overall, this study suggests that water quality remains relatively stable despite changes in the Wash and managers of developing wetlands should not use tributary water as source water.

  13. Heavy Metal Contamination and Salt Efflorescence Associated With Decorative Landscaping Rocks, Las Vegas, Nevada: The Need for Regulations

    NASA Astrophysics Data System (ADS)

    Mrozek, S. A.; Buck, B. J.; Brock, A. L.

    2004-12-01

    Las Vegas, Nevada is one of the fastest growing cities in the United States. Faced with water restrictions, decorative rock xeroscaping has become a very popular form of landscaping. Currently, there are no regulations controlling the geochemistry of the decorative rocks that can be used for these purposes. In this study, we examined three sites containing two different decorative rock products. The landscaping rocks, underlying soil, and surface salt crusts were analyzed to determine their mineralogy and chemistry. Methods of analysis include scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP), thin section analysis, and laser particle size analysis (LPSA). Preliminary results indicate the presence of halite (NaCl), bloedite (Na2Mg(SO4)2 4H2O), a hydrated magnesium sulfate, and possibly copper sulfate and copper chloride mineral phases in the surface salt crusts. Both copper minerals are regarded as hazardous substances by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA); these agencies have established minimum exposure limits for human contact with these substances. Copper sulfate and copper chloride are not naturally occurring minerals in the soils of the Las Vegas Valley, and analyses indicate that their formation may be attributed to the mineralogy of the decorative landscaping rocks. Further testing is needed to characterize this potential health hazard; however the preliminary results of this study demonstrate the need for regulations controlling the geochemistry of decorative rocks used for urban landscaping.

  14. A preliminary assessment of earthquake ground shaking hazard at Yucca Mountain, Nevada and implications to the Las Vegas region

    SciTech Connect

    Wong, I.G.; Green, R.K.; Sun, J.I.; Pezzopane, S.K.; Abrahamson, N.A.; Quittmeyer, R.C.

    1996-12-31

    As part of early design studies for the potential Yucca Mountain nuclear waste repository, the authors have performed a preliminary probabilistic seismic hazard analysis of ground shaking. A total of 88 Quaternary faults within 100 km of the site were considered in the hazard analysis. They were characterized in terms of their probability o being seismogenic, and their geometry, maximum earthquake magnitude, recurrence model, and slip rate. Individual faults were characterized by maximum earthquakes that ranged from moment magnitude (M{sub w}) 5.1 to 7.6. Fault slip rates ranged from a very low 0.00001 mm/yr to as much as 4 mm/yr. An areal source zone representing background earthquakes up to M{sub w} 6 1/4 = 1/4 was also included in the analysis. Recurrence for these background events was based on the 1904--1994 historical record, which contains events up to M{sub w} 5.6. Based on this analysis, the peak horizontal rock accelerations are 0.16, 0.21, 0.28, and 0.50 g for return periods of 500, 1,000, 2,000, and 10,000 years, respectively. In general, the dominant contributor to the ground shaking hazard at Yucca Mountain are background earthquakes because of the low slip rates of the Basin and Range faults. A significant effect on the probabilistic ground motions is due to the inclusion of a new attenuation relation developed specifically for earthquakes in extensional tectonic regimes. This relation gives significantly lower peak accelerations than five other predominantly California-based relations used in the analysis, possibly due to the lower stress drops of extensional earthquakes compared to California events. Because Las Vegas is located within the same tectonic regime as Yucca Mountain, the seismic sources and path and site factors affecting the seismic hazard at Yucca Mountain also have implications to Las Vegas. These implications are discussed in this paper.

  15. Reversible reduction of estrone to 17β-estradiol by Rhizobium, Sphingopyxis, and Pseudomonas isolates from the Las Vegas Wash

    USGS Publications Warehouse

    Blunt, Susanna; Benotti, Mark; Rosen, Michael R.; Hedlund, Brian; Moser, Duane

    2017-01-01

    Environmental endocrine-disrupting compounds (EDCs) are a growing concern as studies reveal their persistence and detrimental effects on wildlife. Microorganisms are known to affect the transformation of steroid EDCs; however, the diversity of estrogen-degrading microorganisms and the range of transformations they mediate remain relatively little studied. In mesocosms, low concentrations of added estrone (E1) and 17β-estradiol (E2) were removed by indigenous microorganisms from Las Vegas Wash water within 2 wk. Three bacterial isolates, Rhizobium sp. strain LVW-9, Sphingopyxis sp. strain LVW-12, and Pseudomonas sp. strain LVW-PC, were enriched from Las Vegas Wash water on E1 and E2 and used for EDC transformation studies. In the presence of alternative carbon sources, LVW-9 and LVW-12 catalyzed near-stoichiometric reduction of E1 to E2 but subsequently reoxidized E2 back to E1; whereas LVW-PC minimally reduced E1 to E2 but effectively oxidized E2 to E1 after a 20-d lag. In the absence of alternative carbon sources, LVW-12 and LVW-PC oxidized E2 to E1. This report documents the rapid and sometimes reversible microbial transformation of E1 and E2 and the slow degradation of 17α-ethinylestradiol in urban stream water and extends the list of known estrogen-transforming bacteria to the genera Rhizobium and Sphingopyxis. These results suggest that discharge of steroid estrogens via wastewater could be reduced through tighter control of redox conditions and may assist in future risk assessments detailing the environmental fate of estrogens through evidence that microbial estrogen transformations may be affected by environmental conditions or growth status.

  16. Environmental Assessment for Enhanced Use Lease of U.S. Air Force Lands to the City of North Las Vegas for Construction and Operation of a Water Reclamation Facility, Nellis Air Force Base, Nevada

    DTIC Science & Technology

    2008-01-01

    Federal Status Habitat Potential to occur within Project Area Razorback sucker Xyrauchen texanus Endangered Backwaters, sloughs, oxbow lakes , and...up to 39 per cent of water use in the valley, with the remainder coming from Lake Mead (Las Vegas Valley Water District 2008). 3.7.1 Surface Water...City of North Las Vegas North Las Vegas Water Reclamation Facility Environmental Assessment 8 Site 6 (Bay Lake Trail and Kier Road): Advantages to

  17. The influence of faults in basin-fill deposits on land subsidence, Las Vegas Valley, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Burbey, Thomas

    2002-07-01

    The role of horizontal deformation caused by pumping of confined-aquifer systems is recognized as contributing to the development of earth fissures in semiarid regions, including Las Vegas Valley, Nevada. In spite of stabilizing water levels, new earth fissures continue to develop while existing ones continue to lengthen and widen near basin-fill faults. A three-dimensional granular displacement model based on Biot's consolidation theory (Biot, MA, 1941, General theory of three-dimensional consolidation. Jour. Applied Physics 12:155-164) has been used to evaluate the nature of displacement in the vicinity of two vertical faults. The fault was simulated as (1) a low-permeability barrier to horizontal flow, (2) a gap or structural break in the medium, but where groundwater flow is not obstructed, and (3) a combination of conditions (1) and (2). Results indicate that the low-permeability barrier greatly enhances horizontal displacement. The fault plane also represents a location of significant differential vertical subsidence. Large computed strains in the vicinity of the fault may suggest high potential for failure and the development of earth fissures when the fault is assumed to have low permeability. Results using a combination of the two boundaries suggest that potential fissure development may be great at or near the fault plane and that horizontal deformation is likely to play a key role in this development. Résumé. On considère que la déformation horizontale provoquée par un pompage dans un aquifère captif joue un rôle dans le développement des fissures du sol en régions semi-arides, comme la vallée de Las Vegas (Nevada). Malgré des niveaux d'eau stabilisés, de nouvelles fissures du sol continuent de se développer en longueur et en largeur au voisinage de failles dans les bassins sédimentaires. Un modèle de déplacement granulaire tri-dimensionnel, basé sur la théorie de la consolidation de Biot (Biot, M A, 1941, General theory of three

  18. Clinical cutaneous leishmaniasis rates are associated with household Lutzomyia gomezi, Lu. Panamensis, and Lu. trapidoi abundance in Trinidad de Las Minas, western Panama.

    PubMed

    Saldaña, Azael; Chaves, Luis F; Rigg, Chystrie A; Wald, Coridalia; Smucker, Joanne E; Calzada, Jose E

    2013-03-01

    American cutaneous leishmaniasis (ACL) transmission patterns have been increasingly associated with domestic and peridomestic environments. Here, we present results from an epidemiological survey of 94 people from 24 households in Trinidad de Las Minas, western Panama. We studied the role of sand fly abundance, housing quality, peridomicile landscape matrix, and vegetation structure on shaping household clinical ACL rate patterns at Trinidad de Las Minas. We found that sand fly abundance was significantly associated with household clinical ACL rates, with a 6% rate increase for each additional Lutzomyia gomezi sand fly found inside a domicile.

  19. Clinical Cutaneous Leishmaniasis Rates Are Associated with Household Lutzomyia gomezi, Lu. Panamensis, and Lu. trapidoi Abundance in Trinidad de Las Minas, Western Panama

    PubMed Central

    Saldaña, Azael; Chaves, Luis F.; Rigg, Chystrie A.; Wald, Coridalia; Smucker, Joanne E.; Calzada, Jose E.

    2013-01-01

    American cutaneous leishmaniasis (ACL) transmission patterns have been increasingly associated with domestic and peridomestic environments. Here, we present results from an epidemiological survey of 94 people from 24 households in Trinidad de Las Minas, western Panama. We studied the role of sand fly abundance, housing quality, peridomicile landscape matrix, and vegetation structure on shaping household clinical ACL rate patterns at Trinidad de Las Minas. We found that sand fly abundance was significantly associated with household clinical ACL rates, with a 6% rate increase for each additional Lutzomyia gomezi sand fly found inside a domicile. PMID:23339202

  20. Cómo aumentar la actividad física de los niños durante el período del recreo en las escuelas

    PubMed Central

    Ludwig, David

    2014-01-01

    Objetivos. Analizamos si la participación de las escuelas en el Programa de Mejoramiento del Recreo (PMR) en la primavera del año 2011 estuvo asociada a tasas más altas de actividad física intensa en los niños. Métodos. En el PMR, un coordinador dirige a los niños para que practiquen juegos adecuados para la edad a fin de aumentar su nivel de actividad física. Durante el recreo en 25 escuelas primarias públicas de la ciudad de Nueva York (15 participantes en el PMR, 10 no participantes en el PMR) los investigadores observaron algunas áreas predeterminadas (n = 1 339 observaciones) y registraron el número de niños que estaban sedentarios, caminando o muy activos. Resultados. Tras el análisis estadístico con múltiples variables se encontró que la participación en el PMR era una variable predictiva significativa (P = 0,027) de la tasa de actividad física intensa (porcentaje de niños muy activos en las áreas de observación) cuyas medias de los mínimos cuadrados fueron de 41% en las escuelas participantes en el PMR y de 27% en escuelas no participantes en el PMR. En las escuelas participantes en el PMR se siguió registrando una tasa significativamente superior incluso cuando el coordinador de juegos no estaba en el área de observación, lo que sugiere un cambio en la cultura del recreo en las escuelas que participan en este programa. Conclusiones. La tasa de actividad física intensa en las escuelas participantes en el PMR fue 14 puntos porcentuales (o 52%) superior a la tasa registrada en las escuelas no participantes en el PMR. Esta intervención de bajo costo podría ser un agregado valioso a las herramientas para combatir la obesidad infantil y podría valer la pena reproducirla en otros sitios. PMID:24899455