Science.gov

Sample records for acid pool sizes

  1. Tricarboxylic acid cycle intermediate pool size: functional importance for oxidative metabolism in exercising human skeletal muscle.

    PubMed

    Bowtell, Joanna L; Marwood, Simon; Bruce, Mark; Constantin-Teodosiu, Dumitru; Greenhaff, Paul L

    2007-01-01

    The tricarboxylic acid (TCA) cycle is the major final common pathway for oxidation of carbohydrates, lipids and some amino acids, which produces reducing equivalents in the form of nicotinamide adenine dinucleotide and flavin adenine dinucleotide that result in production of large amounts of adenosine triphosphate (ATP) via oxidative phosphorylation. Although regulated primarily by the products of ATP hydrolysis, in particular adenosine diphosphate, the rate of delivery of reducing equivalents to the electron transport chain is also a potential regulatory step of oxidative phosphorylation. The TCA cycle is responsible for the generation of approximately 67% of all reducing equivalents per molecule of glucose, hence factors that influence TCA cycle flux will be of critical importance for oxidative phosphorylation. TCA cycle flux is dependent upon the supply of acetyl units, activation of the three non-equilibrium reactions within the TCA cycle, and it has been suggested that an increase in the total concentration of the TCA cycle intermediates (TCAi) is also necessary to augment and maintain TCA cycle flux during exercise. This article reviews the evidence of the functional importance of the TCAi pool size for oxidative metabolism in exercising human skeletal muscle. In parallel with increased oxidative metabolism and TCA cycle flux during exercise, there is an exercise intensity-dependent 4- to 5-fold increase in the concentration of the TCAi. TCAi concentration reaches a peak after 10-15 minutes of exercise, and thereafter tends to decline. This seems to support the suggestion that the concentration of TCAi may be of functional importance for oxidative phosphorylation. However, researchers have been able to induce dissociations between TCAi pool size and oxidative energy provision using a variety of nutritional, pharmacological and exercise interventions. Brief periods of endurance training (5 days or 7 weeks) have been found to result in reduced TCAi pool

  2. Tricarboxylic acid cycle intermediate pool size: functional importance for oxidative metabolism in exercising human skeletal muscle.

    PubMed

    Bowtell, Joanna L; Marwood, Simon; Bruce, Mark; Constantin-Teodosiu, Dumitru; Greenhaff, Paul L

    2007-01-01

    The tricarboxylic acid (TCA) cycle is the major final common pathway for oxidation of carbohydrates, lipids and some amino acids, which produces reducing equivalents in the form of nicotinamide adenine dinucleotide and flavin adenine dinucleotide that result in production of large amounts of adenosine triphosphate (ATP) via oxidative phosphorylation. Although regulated primarily by the products of ATP hydrolysis, in particular adenosine diphosphate, the rate of delivery of reducing equivalents to the electron transport chain is also a potential regulatory step of oxidative phosphorylation. The TCA cycle is responsible for the generation of approximately 67% of all reducing equivalents per molecule of glucose, hence factors that influence TCA cycle flux will be of critical importance for oxidative phosphorylation. TCA cycle flux is dependent upon the supply of acetyl units, activation of the three non-equilibrium reactions within the TCA cycle, and it has been suggested that an increase in the total concentration of the TCA cycle intermediates (TCAi) is also necessary to augment and maintain TCA cycle flux during exercise. This article reviews the evidence of the functional importance of the TCAi pool size for oxidative metabolism in exercising human skeletal muscle. In parallel with increased oxidative metabolism and TCA cycle flux during exercise, there is an exercise intensity-dependent 4- to 5-fold increase in the concentration of the TCAi. TCAi concentration reaches a peak after 10-15 minutes of exercise, and thereafter tends to decline. This seems to support the suggestion that the concentration of TCAi may be of functional importance for oxidative phosphorylation. However, researchers have been able to induce dissociations between TCAi pool size and oxidative energy provision using a variety of nutritional, pharmacological and exercise interventions. Brief periods of endurance training (5 days or 7 weeks) have been found to result in reduced TCAi pool

  3. Protein Restriction with Amino Acid-Balanced Diets Shrinks Circulating Pool Size of Amino Acid by Decreasing Expression of Specific Transporters in the Small Intestine

    PubMed Central

    Luo, Min; Zhang, Xin; Sun, Wen Juan; Jiao, Ning; Li, De Fa; Yin, Jing Dong

    2016-01-01

    Dietary protein restriction is not only beneficial to health and longevity in humans, but also protects against air pollution and minimizes feeding cost in livestock production. However, its impact on amino acid (AA) absorption and metabolism is not quite understood. Therefore, the study aimed to explore the effect of protein restriction on nitrogen balance, circulating AA pool size, and AA absorption using a pig model. In Exp.1, 72 gilts weighting 29.9 ± 1.5 kg were allocated to 1 of the 3 diets containing 14, 16, or 18% CP for a 28-d trial. Growth (n = 24), nitrogen balance (n = 6), and the expression of small intestinal AA and peptide transporters (n = 6) were evaluated. In Exp.2, 12 barrows weighting 22.7 ± 1.3 kg were surgically fitted with catheters in the portal and jejunal veins as well as the carotid artery and assigned to a diet containing 14 or 18% CP. A series of blood samples were collected before and after feeding for determining the pool size of circulating AA and AA absorption in the portal vein, respectively. Protein restriction did not sacrifice body weight gain and protein retention, since nitrogen digestibility was increased as dietary protein content reduced. However, the pool size of circulating AA except for lysine and threonine, and most AA flux through the portal vein were reduced in pigs fed the low protein diet. Meanwhile, the expression of peptide transporter 1 (PepT-1) was stimulated, but the expression of the neutral and cationic AA transporter systems was depressed. These results evidenced that protein restriction with essential AA-balanced diets, decreased AA absorption and reduced circulating AA pool size. Increased expression of small intestinal peptide transporter PepT-1 could not compensate for the depressed expression of jejunal AA transporters for AA absorption. PMID:27611307

  4. Protein Restriction with Amino Acid-Balanced Diets Shrinks Circulating Pool Size of Amino Acid by Decreasing Expression of Specific Transporters in the Small Intestine.

    PubMed

    Qiu, Kai; Qin, Chun Fu; Luo, Min; Zhang, Xin; Sun, Wen Juan; Jiao, Ning; Li, De Fa; Yin, Jing Dong

    2016-01-01

    Dietary protein restriction is not only beneficial to health and longevity in humans, but also protects against air pollution and minimizes feeding cost in livestock production. However, its impact on amino acid (AA) absorption and metabolism is not quite understood. Therefore, the study aimed to explore the effect of protein restriction on nitrogen balance, circulating AA pool size, and AA absorption using a pig model. In Exp.1, 72 gilts weighting 29.9 ± 1.5 kg were allocated to 1 of the 3 diets containing 14, 16, or 18% CP for a 28-d trial. Growth (n = 24), nitrogen balance (n = 6), and the expression of small intestinal AA and peptide transporters (n = 6) were evaluated. In Exp.2, 12 barrows weighting 22.7 ± 1.3 kg were surgically fitted with catheters in the portal and jejunal veins as well as the carotid artery and assigned to a diet containing 14 or 18% CP. A series of blood samples were collected before and after feeding for determining the pool size of circulating AA and AA absorption in the portal vein, respectively. Protein restriction did not sacrifice body weight gain and protein retention, since nitrogen digestibility was increased as dietary protein content reduced. However, the pool size of circulating AA except for lysine and threonine, and most AA flux through the portal vein were reduced in pigs fed the low protein diet. Meanwhile, the expression of peptide transporter 1 (PepT-1) was stimulated, but the expression of the neutral and cationic AA transporter systems was depressed. These results evidenced that protein restriction with essential AA-balanced diets, decreased AA absorption and reduced circulating AA pool size. Increased expression of small intestinal peptide transporter PepT-1 could not compensate for the depressed expression of jejunal AA transporters for AA absorption.

  5. Protein Restriction with Amino Acid-Balanced Diets Shrinks Circulating Pool Size of Amino Acid by Decreasing Expression of Specific Transporters in the Small Intestine.

    PubMed

    Qiu, Kai; Qin, Chun Fu; Luo, Min; Zhang, Xin; Sun, Wen Juan; Jiao, Ning; Li, De Fa; Yin, Jing Dong

    2016-01-01

    Dietary protein restriction is not only beneficial to health and longevity in humans, but also protects against air pollution and minimizes feeding cost in livestock production. However, its impact on amino acid (AA) absorption and metabolism is not quite understood. Therefore, the study aimed to explore the effect of protein restriction on nitrogen balance, circulating AA pool size, and AA absorption using a pig model. In Exp.1, 72 gilts weighting 29.9 ± 1.5 kg were allocated to 1 of the 3 diets containing 14, 16, or 18% CP for a 28-d trial. Growth (n = 24), nitrogen balance (n = 6), and the expression of small intestinal AA and peptide transporters (n = 6) were evaluated. In Exp.2, 12 barrows weighting 22.7 ± 1.3 kg were surgically fitted with catheters in the portal and jejunal veins as well as the carotid artery and assigned to a diet containing 14 or 18% CP. A series of blood samples were collected before and after feeding for determining the pool size of circulating AA and AA absorption in the portal vein, respectively. Protein restriction did not sacrifice body weight gain and protein retention, since nitrogen digestibility was increased as dietary protein content reduced. However, the pool size of circulating AA except for lysine and threonine, and most AA flux through the portal vein were reduced in pigs fed the low protein diet. Meanwhile, the expression of peptide transporter 1 (PepT-1) was stimulated, but the expression of the neutral and cationic AA transporter systems was depressed. These results evidenced that protein restriction with essential AA-balanced diets, decreased AA absorption and reduced circulating AA pool size. Increased expression of small intestinal peptide transporter PepT-1 could not compensate for the depressed expression of jejunal AA transporters for AA absorption. PMID:27611307

  6. Amino Acid Synthesis in Photosynthesizing Spinach Cells: Effects of Ammonia on Pool Sizes and Rates of Labeling from 14CO2

    SciTech Connect

    Larsen, Peder Olesen; Cornwell, Karen L.; Gee, Sherry L.; Bassham, James A.

    1981-08-01

    In this paper, isolated cells from leaves of Spinacia oleracea have been maintained in a state capable of high rates of photosynthetic CO2 fixation for more than 60 hours. The incorporation of 14CO2 under saturating CO2 conditions into carbohydrates, carboxylic acids, and amino acids, and the effect of ammonia on this incorporation have been studied. Total incorporation, specific radioactivity, and pool size have been determined as a function of time for most of the protein amino acids and for γ-aminobutyric acid. The measurements of specific radio-activities and of the approaches to 14C “saturation” of some amino acids indicate the presence and relative sizes of metabolically active and passive pools of these amino acids. Added ammonia decreased carbon fixation into carbohydrates and increased fixation into carboxylic acids and amino acids. Different amino acids were, however, affected in different and highly specific ways. Ammonia caused large stimulatory effects in incorporation of 14C into glutamine (a factor of 21), aspartate, asparagine, valine, alanine, arginine, and histidine. No effect or slight decreases were seen in glycine, serine, phenylalanine, and tyrosine labeling. In the case of glutamate, 14C labeling decreased, but specific radioactivity increased. The production of labeled γ-aminobutyric acid was virtually stopped by ammonia. The results indicate that added ammonia stimulates the reactions mediated by pyruvate kinase and phosphoenolpyruvate carboxylase, as seen with other plant systems. Finally, the data on the effects of added ammonia on total labeling, pool sizes, and specific radioactivities of several amino acids provides a number of indications about the intracellular sites of principal synthesis from carbon skeletons of these amino acids and the selective nature of effects of increased intracellular ammonia concentration on such synthesis.

  7. Delineation of biochemical, molecular, and physiological changes accompanying bile acid pool size restoration in Cyp7a1−/− mice fed low levels of cholic acid

    PubMed Central

    Jones, Ryan D.; Repa, Joyce J.; Russell, David W.; Dietschy, John M.

    2012-01-01

    Cholesterol 7α-hydroxylase (CYP7A1) is the initiating and rate-limiting enzyme in the neutral pathway that coverts cholesterol to primary bile acids (BA). CYP7A1-deficient (Cyp7a1−/−) mice have a depleted BA pool, diminished intestinal cholesterol absorption, accelerated fecal sterol loss, and increased intestinal cholesterol synthesis. To determine the molecular and physiological effects of restoring the BA pool in this model, adult female Cyp7a1−/− mice and matching Cyp7a1+/+ controls were fed diets containing cholic acid (CA) at modest levels [0.015, 0.030, and 0.060% (wt/wt)] for 15–18 days. A level of just 0.03% provided a CA intake of ∼12 μmol (4.8 mg) per day per 100 g body wt and was sufficient in the Cyp7a1−/− mice to normalize BA pool size, fecal BA excretion, fractional cholesterol absorption, and fecal sterol excretion but caused a significant rise in the cholesterol concentration in the small intestine and liver, as well as a marked inhibition of cholesterol synthesis in these organs. In parallel with these metabolic changes, there were marked shifts in intestinal and hepatic expression levels for many target genes of the BA sensor farnesoid X receptor, as well as genes involved in cholesterol transport, especially ATP-binding cassette (ABC) transporter A1 (ABCA1) and ABCG8. In Cyp7a1+/+ mice, this level of CA supplementation did not significantly disrupt BA or cholesterol metabolism, except for an increase in fecal BA excretion and marginal changes in mRNA expression for some BA synthetic enzymes. These findings underscore the importance of using moderate dietary BA levels in studies with animal models. PMID:22628034

  8. Lowering bile acid pool size with a synthetic farnesoid X receptor (FXR) agonist induces obesity and diabetes through reduced energy expenditure.

    PubMed

    Watanabe, Mitsuhiro; Horai, Yasushi; Houten, Sander M; Morimoto, Kohkichi; Sugizaki, Taichi; Arita, Eri; Mataki, Chikage; Sato, Hiroyuki; Tanigawara, Yusuke; Schoonjans, Kristina; Itoh, Hiroshi; Auwerx, Johan

    2011-07-29

    We evaluated the metabolic impact of farnesoid X receptor (FXR) activation by administering a synthetic FXR agonist (GW4064) to mice in which obesity was induced by a high fat diet. Administration of GW4064 accentuated body weight gain and glucose intolerance induced by the high fat diet and led to a pronounced worsening of the changes in liver and adipose tissue. Mechanistically, treatment with GW4064 decreased bile acid (BA) biosynthesis, BA pool size, and energy expenditure, whereas reconstitution of the BA pool in these GW4064-treated animals by BA administration dose-dependently reverted the metabolic abnormalities. Our data therefore suggest that activation of FXR with synthetic agonists is not useful for long term management of the metabolic syndrome, as it reduces the BA pool size and subsequently decreases energy expenditure, translating as weight gain and insulin resistance. In contrast, expansion of the BA pool size, which can be achieved by BA administration, could be an interesting strategy to manage the metabolic syndrome.

  9. Changes in Pool Sizes of Free Amino Acids and Amides in Leaves and Plastids of Zea mays during Leaf Development.

    PubMed

    Chapman, D J; Leech, R M

    1979-03-01

    The concentrations of free amino acids and amides within isolated maize (Zea mays L.) plastids were determined and compared with concentrations in the leaf tissue. The concentrations were different for each individual amino acid and varied between 1 and 10 millimolar. At five different developmental stages concentrations in the plastids were greater than those in the intact leaf tissue. During development, from the proplastid stage to the mature chloroplast, the amount of each amino acid per plastid remained relatively constant, but there were decreases in concentrations of plastid amino acids resulting from the developmental increase in plastid volume. In proplastids, the free amino acids were present in greater concentrations than those previously found to inhibit partially amino acid-synthesizing enzymes located in chloroplasts. In the chloroplasts, the molarities of the free amino acids were within the range known to inhibit amino acid-synthesizing enzymes.

  10. Temperature and size variabilities of the Western pacific warm pool.

    PubMed

    Yan, X H; Ho, C R; Zheng, Q; Klemas, V

    1992-12-01

    Variabilities in sea-surface temperature and size of the Western Pacific Warm Pool were tracked with 10 years of satellite multichannel sea-surface temperature observations from 1982 to 1991. The results show that both annual mean sea-surface temperature and the size of the warm pool increased from 1983 to 1987 and fluctuated after 1987. Possible causes of these variations include solar irradiance variabilities, EI Niño-Southern Oscillation events, volcanic activities, and global warming.

  11. Gravity and Heater Size Effects on Pool Boiling Heat Transfer

    NASA Technical Reports Server (NTRS)

    Kim, Jungho; Raj, Rishi

    2014-01-01

    The current work is based on observations of boiling heat transfer over a continuous range of gravity levels between 0g to 1.8g and varying heater sizes with a fluorinert as the test liquid (FC-72/n-perfluorohexane). Variable gravity pool boiling heat transfer measurements over a wide range of gravity levels were made during parabolic flight campaigns as well as onboard the International Space Station. For large heaters and-or higher gravity conditions, buoyancy dominated boiling and heat transfer results were heater size independent. The power law coefficient for gravity in the heat transfer equation was found to be a function of wall temperature under these conditions. Under low gravity conditions and-or for smaller heaters, surface tension forces dominated and heat transfer results were heater size dependent. A pool boiling regime map differentiating buoyancy and surface tension dominated regimes was developed along with a unified framework that allowed for scaling of pool boiling over a wide range of gravity levels and heater sizes. The scaling laws developed in this study are expected to allow performance quantification of phase change based technologies under variable gravity environments eventually leading to their implementation in space based applications.

  12. Analysis of Free Amino Acid Pools in Fungal Mycelia

    PubMed Central

    Heathcote, J. G.; Davies, D. M.; Haworth, C.

    1972-01-01

    Free amino acid pools derived from three different types of fungal mycelia have been analyzed by the method of Heathcote and Haworth by using thinlayer chromatography. The preliminary extraction was carried out with boiling water and interfering proteins; peptides and salts were first removed by means of an ion-retardation resin. As far as determined, the results obtained represent the first quantitative analysis of fungal amino acid pools. PMID:4622829

  13. Inorganic pyrophosphate pool size and turnover rate in arthritic joints.

    PubMed

    Camerlain, M; McCarty, D J; Silcox, D C; Jung, A

    1975-06-01

    Recent studies have shown elevated inorganic pyrophosphate (PPi) levels in most knee joint fluid supernates from patients with pseudogout (PG) or osteoarthritis (OA) and more modestly elevated levels in some supernates from patients with gout or rheumatoid arthritis (RA) relative to PPi levels found in the venous blood plasma of normal or arthritic subjects. We measured the intraarticular PPi pool and its rate of turnover to better understand the significance of the joint fluid-plasma PPi gradient. Preliminary studies in rabbits showed that (32-P)PPi passed from joint space to blood and vice versa without detectable hydrolysis. Incubation of natural or synthetic calcium pyrophosphate dihydrate (CPPD) microcrystals with synovial fluid in vitro in the presence of (32P)PPi tracer showed no change in PPi specific activity in the supernate over a 19-h period so that exchange of PPi in solution with that in CPPD microcrystals could be ignored. Clearance rates of (32P)PPi and of (33P)Pi, as determined by serially sampling the catheterized knee joints of volunteers with various types of arthritis over a 3-h period, were nearly identical. The (32P)PPi/(32P)Pi was determined in each sample. A mixture of a large excess of cold PPi did not influence the clearance rate of either nuclide. The quantity of PPi turned over per hous was calculated from the pool size as determined by isotope dilution and the turnover rate. The residual joint fluid nuclide was shown to be (32P)PPi. The PPi pool was generally smaller and the rate of turnover was greater in clinically inflamed joints. The mean plus or minus SEM pool size (mu-moles) and turnover rate (percent/hour) in PG knees was 0.23 plus or minus 0.07 and 117 plus or minus 11.9, hydrolysis rate (%/h) to Pi was 27.7 plus or minus 13.2; in OA knees: 0.45 plus or minus 0.26 and 72 plus or minus 9.2, hydrolysis 6.9 plus or minus 0.9; in gouty knees: 0.8 plus or minus 0.41 and 50 plus or minus 11.6, hydrolysis 9.8 plus or minus 2.8; and in

  14. On the Sizes and Lifetimes of Cold Pools

    NASA Astrophysics Data System (ADS)

    Romps, D. M.; Jeevanjee, N.

    2015-12-01

    Cold pools of air, which are formed by evaporating precipitation, play a critical role in the triggering of new precipitation, especially in unorganized tropical convection. Despite their recognized importance, little effort has been devoted to building simple models of their dynamics. Here, analytical expressions are derived for the radius, height, and buoyancy of a cold pool as a function of time. These expressions give a simple equation for the radius of a cold pool when it terminates by ceasing to be cold. The terminal radius of a cold pool is relatively insensitive to its initial conditions, with a typical maximum radius of about 14 times the initial radius, give or take a factor of two. The terminal time of a cold pool, on the other hand, can vary over orders of magnitude depending on its initial potential and kinetic energy. These predictions are validated against large-eddy simulations.

  15. Estimating the number and sizes of undiscovered oil and gas pools

    SciTech Connect

    Long, K.R.

    1988-01-01

    This study introduces a new specification of oil and gas exploration as a sampling process, in order to estimate the number and sizes of undiscovered oil and gas pools by statistical inference from discovered pools as a sample. Oil and gas exploration is quite unlike drawing samples at random in that actual sampling is sized-biased, subject to truncation of uneconomic pools, and to censorship of discovered pool sizes. The method of estimating the number and sizes of undiscovered pools proposed in this study specifically accounts for these non-random components of exploration as a sampling process, and can be easily implemented using the Expectation-Maximization algorithm. The method allows for choices between single and multiple point truncation of uneconomic pool sizes, and generalizes quite easily to the bivariate case necessary to analyze plays with pools that contain oil with associated gas. Its usefulness is enhanced by the introduction of powerful tests of fit of the lognormal distribution to the distribution of discovered pool sizes, and of meaningful measures of the uncertainty of estimates of the number and sizes of undiscovered pools. Application of the method to oil and gas plays in the San Juan basin of northwest New Mexico show that it yields quite reasonable and useful results. The method, when applied to data analyzed using other methods of estimating the number and sizes of undiscovered pools, confirms that failure to account for truncation of uneconomic pools will result in an overestimate of the average size of pools in a play. By avoiding this, and other, problems, the proposed estimation procedure should lead to better assessments of a play's potential for future discoveries of economically recoverable oil and gas.

  16. 10 CFR 905.32 - Resource extensions and resource pool size.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Resource extensions and resource pool size. 905.32 Section... § 905.32 Resource extensions and resource pool size. (a) Western will extend a project-specific percentage of the marketable resource, determined to be available at the time future resource...

  17. Effects of artificial depletion of the bile acid pool in man.

    PubMed Central

    Jazrawi, R P; Bridges, C; Joseph, A E; Northfield, T C

    1986-01-01

    In order to elucidate the relationship between bile acid pool size and cholesterol saturation index of fasting state gall bladder bile, we artificially depleted the bile acid pool in 12 healthy volunteers. Bile acid pool size decreased from 7.6 +/- 0.9 to 5.8 +/- 0.7 mmol (mean +/- SEM, p less than 0.01), and saturation index of fasting state gall bladder bile increased from 0.93 +/- 0.07 to 1.18 +/- 0.07 (p less than 0.001). There was no alteration in saturation index of basal or stimulated hepatic bile. There was no change in gall bladder storage of basal hepatic bile, nor in the proportion of the bile acid pool stored in the gall bladder. The bile acid mass in the gall bladder fell from 4.9 +/- 0.5 to 3.4 +/- 0.4 mmol (p less than 0.05) and phospholipid mass from 1.6 +/- 0.3 to 1.2 +/- 0.2 mmol (p less than 0.05), but there was no change in cholesterol mass. The gall bladder volume fell from 30 +/- 4 to 18 +/- 2 ml (p less than 0.01). These results suggest that artificial depletion of the bile acid pool increased saturation index of fasting state gall bladder bile without altering saturation index of basal or stimulated hepatic bile; it probably increased the ratio of basal: stimulated hepatic bile within the gall bladder by decreasing gall bladder storage of stimulated hepatic bile. PMID:3732888

  18. Instantaneous liquid release from a rail tanker: the influence of noise shields on pool shape and pool size.

    PubMed

    Rosmuller, Nils

    2009-05-30

    In the Netherlands, the Betuweline is a dedicated freight railway. It will, among other things, be used for transportation of all kinds of hazardous materials from the Port of Rotterdam to the German Hinterland and vice versa. The line is approximately 150 km long. Alongside the line, more than 100 km noise shields have been constructed. The question is how, and to what extent, this noise shield will affect the pool shape and size of an instantaneous release of a flammable liquid, such as liquefied petroleum gas (LPG). In case of an instantaneous release of liquid from a rail tanker (50 m(3)), both risk analysts and emergency responders use a circular pool shape of about 600 m(2) would result. To assess the influence of a noise shield, a full scale test was conducted on an already constructed part of the Betuweline. A rail tanker was filled with 50 m(3) red-colored environmentally safe liquid. The liquid was instantaneously released. A very peculiar pool shape actually results due to the presence of a noise shield. A zone between the rails and the noise shield (2m wide and 90 m long) is within 2-3 min filled with 15 cm of liquid. The total pool size area was about 750 m(2). Both shape and size deviate substantially from the traditional figures. These insights are both relevant to emergency responders for disaster abatement purposes and to risk analysts for effective modeling purposes. The Dutch Ministry of Transport is examining possible strategies to deal with these results. The results of this study are based upon one single instantaneous release test. In addition, it is valuable to find out what the pool shape and size would be in case of a continuous release from the rail tanker near a noise shield.

  19. Tracking Diacylglycerol and Phosphatidic Acid Pools in Budding Yeast

    PubMed Central

    Ganesan, Suriakarthiga; Shabits, Brittney N.; Zaremberg, Vanina

    2015-01-01

    Phosphatidic acid (PA) and diacylglycerol (DAG) are key signaling molecules and important precursors for the biosynthesis of all glycerolipids found in eukaryotes. Research conducted in the model organism Saccharomyces cerevisiae has been at the forefront of the identification of the enzymes involved in the metabolism and transport of PA and DAG. Both these lipids can alter the local physical properties of membranes by introducing negative curvature, but the anionic nature of the phosphomonoester headgroup in PA sets it apart from DAG. As a result, the mechanisms underlying PA and DAG interaction with other lipids and proteins are notoriously different. This is apparent from the analysis of the protein domains responsible for recognition and binding to each of these lipids. We review the current evidence obtained using the PA-binding proteins and domains fused to fluorescent proteins for in vivo tracking of PA pools in yeast. In addition, we present original results for visualization of DAG pools in yeast using the C1 domain from mammalian PKCδ. An emerging first cellular map of the distribution of PA and DAG pools in actively growing yeast is discussed. PMID:27081314

  20. Effect of species pool size on species occurrence frequencies: Musical chairs on islands.

    PubMed

    Diamond, J

    1982-04-01

    If species interactions affect species distributions, then species occurrence frequencies (nu(i)), defined as the fraction of an archipelago's islands that species i inhabits, should vary with species pool size. A "natural experiment" approximating this test is provided by the Bismarck, Solomon, and New Hebrides archipelagoes, whose bird species pools decrease in that order, the species of each archipelago being mostly a subset of those of the next richer archipelago. The average nu for an archipelago's species decreases with archipelago pool size. In the archipelago with the largest pool, most species are on few islands and few species are on most islands, whereas the reverse is true in the archipelago with the smallest pool. For species shared between two or more archipelagoes, nu(i) decreases with pool size or number of species in the same guild. These interarchipelagal differences in nu(i) or average nu reflect differences in level of interspecific competition, which reduces nus in species-rich archipelagoes in two ways: usually, by reducing a species' incidence on small islands and restricting the species to larger islands; less often (for so-called supertramps), by restricting a species to small islands. PMID:16578762

  1. Effect of species pool size on species occurrence frequencies: Musical chairs on islands.

    PubMed

    Diamond, J

    1982-04-01

    If species interactions affect species distributions, then species occurrence frequencies (nu(i)), defined as the fraction of an archipelago's islands that species i inhabits, should vary with species pool size. A "natural experiment" approximating this test is provided by the Bismarck, Solomon, and New Hebrides archipelagoes, whose bird species pools decrease in that order, the species of each archipelago being mostly a subset of those of the next richer archipelago. The average nu for an archipelago's species decreases with archipelago pool size. In the archipelago with the largest pool, most species are on few islands and few species are on most islands, whereas the reverse is true in the archipelago with the smallest pool. For species shared between two or more archipelagoes, nu(i) decreases with pool size or number of species in the same guild. These interarchipelagal differences in nu(i) or average nu reflect differences in level of interspecific competition, which reduces nus in species-rich archipelagoes in two ways: usually, by reducing a species' incidence on small islands and restricting the species to larger islands; less often (for so-called supertramps), by restricting a species to small islands.

  2. An approximate likelihood estimator for the prevalence of infections in vectors using pools of varying sizes.

    PubMed

    Santos, James D; Dorgam, Diana

    2016-09-01

    There are several arthropods that can transmit disease to humans. To make inferences about the rate of infection of these arthropods, it is common to collect a large sample of vectors, divide them into groups (called pools), and apply a test to detect infection. This paper presents an approximate likelihood point estimator to rate of infection for pools of different sizes, when the variability of these sizes is small and the infection rate is low. The performance of this estimator was evaluated in four simulated scenarios, created from real experiments selected in the literature. The new estimator performed well in three of these scenarios. As expected, the new estimator performed poorly in the scenario with great variability in the size of the pools for some values of the parameter space. PMID:27159117

  3. Determination of a temperature sensor location for monitoring weld pool size in GMAW

    SciTech Connect

    Boo, K.S.; Cho, H.S. . Dept. of Precision Engineering and Mechatronics)

    1994-11-01

    This paper describes a method of determining the optimal sensor location to measure weldment surface temperature, which has a close correlation with weld pool size in the gas metal arc (GMA) welding process. Due to the inherent complexity and nonlinearity in the GMA welding process, the relationship between the weldment surface temperature and the weld pool size varies with the point of measurement. This necessitates an optimal selection of the measurement point to minimize the process nonlinearity effect in estimating the weld pool size from the measured temperature. To determine the optimal sensor location on the top surface of the weldment, the correlation between the measured temperature and the weld pool size is analyzed. The analysis is done by calculating the correlation function, which is based upon an analytical temperature distribution model. To validate the optimal sensor location, a series of GMA bead-on-plate welds are performed on a medium-carbon steel under various welding conditions. A comparison study is given in detail based upon the simulation and experimental results.

  4. 10 CFR 905.32 - Resource extensions and resource pool size.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Resource extensions and resource pool size. 905.32 Section 905.32 Energy DEPARTMENT OF ENERGY ENERGY PLANNING AND MANAGEMENT PROGRAM Power Marketing Initiative... percentage of the marketable resource, determined to be available at the time future resource...

  5. 10 CFR 905.32 - Resource extensions and resource pool size.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Resource extensions and resource pool size. 905.32 Section 905.32 Energy DEPARTMENT OF ENERGY ENERGY PLANNING AND MANAGEMENT PROGRAM Power Marketing Initiative... percentage of the marketable resource, determined to be available at the time future resource...

  6. 10 CFR 905.32 - Resource extensions and resource pool size.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Resource extensions and resource pool size. 905.32 Section 905.32 Energy DEPARTMENT OF ENERGY ENERGY PLANNING AND MANAGEMENT PROGRAM Power Marketing Initiative... percentage of the marketable resource, determined to be available at the time future resource...

  7. 10 CFR 905.32 - Resource extensions and resource pool size.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Resource extensions and resource pool size. 905.32 Section 905.32 Energy DEPARTMENT OF ENERGY ENERGY PLANNING AND MANAGEMENT PROGRAM Power Marketing Initiative... percentage of the marketable resource, determined to be available at the time future resource...

  8. Nitrogen stress affects the turnover and size of nitrogen pools supplying leaf growth in a grass.

    PubMed

    Lehmeier, Christoph Andreas; Wild, Melanie; Schnyder, Hans

    2013-08-01

    The effect of nitrogen (N) stress on the pool system supplying currently assimilated and (re)mobilized N for leaf growth of a grass was explored by dynamic ¹⁵N labeling, assessment of total and labeled N import into leaf growth zones, and compartmental analysis of the label import data. Perennial ryegrass (Lolium perenne) plants, grown with low or high levels of N fertilization, were labeled with ¹⁵NO₃⁻/¹⁴NO₃⁻ from 2 h to more than 20 d. In both treatments, the tracer time course in N imported into the growth zones fitted a two-pool model (r² > 0.99). This consisted of a "substrate pool," which received N from current uptake and supplied the growth zone, and a recycling/mobilizing "store," which exchanged with the substrate pool. N deficiency halved the leaf elongation rate, decreased N import into the growth zone, lengthened the delay between tracer uptake and its arrival in the growth zone (2.2 h versus 0.9 h), slowed the turnover of the substrate pool (half-life of 3.2 h versus 0.6 h), and increased its size (12.4 μg versus 5.9 μg). The store contained the equivalent of approximately 10 times (low N) and approximately five times (high N) the total daily N import into the growth zone. Its turnover agreed with that of protein turnover. Remarkably, the relative contribution of mobilization to leaf growth was large and similar (approximately 45%) in both treatments. We conclude that turnover and size of the substrate pool are related to the sink strength of the growth zone, whereas the contribution of the store is influenced by partitioning between sinks.

  9. Quality of the log-geometric distribution extrapolation for smaller undiscovered oil and gas pool size

    USGS Publications Warehouse

    Chenglin, L.; Charpentier, R.R.

    2010-01-01

    The U.S. Geological Survey procedure for the estimation of the general form of the parent distribution requires that the parameters of the log-geometric distribution be calculated and analyzed for the sensitivity of these parameters to different conditions. In this study, we derive the shape factor of a log-geometric distribution from the ratio of frequencies between adjacent bins. The shape factor has a log straight-line relationship with the ratio of frequencies. Additionally, the calculation equations of a ratio of the mean size to the lower size-class boundary are deduced. For a specific log-geometric distribution, we find that the ratio of the mean size to the lower size-class boundary is the same. We apply our analysis to simulations based on oil and gas pool distributions from four petroleum systems of Alberta, Canada and four generated distributions. Each petroleum system in Alberta has a different shape factor. Generally, the shape factors in the four petroleum systems stabilize with the increase of discovered pool numbers. For a log-geometric distribution, the shape factor becomes stable when discovered pool numbers exceed 50 and the shape factor is influenced by the exploration efficiency when the exploration efficiency is less than 1. The simulation results show that calculated shape factors increase with those of the parent distributions, and undiscovered oil and gas resources estimated through the log-geometric distribution extrapolation are smaller than the actual values. ?? 2010 International Association for Mathematical Geology.

  10. Readily releasable pool size changes associated with long term depression

    PubMed Central

    Goda, Yukiko; Stevens, Charles F.

    1998-01-01

    We have estimated, for hippocampal neurons in culture, the size of the autaptic readily releasable pool before and after stimulation of the sort that produces culture long term depression (LTD). This stimulation protocol causes a decrease in the pool size that is proportional to the depression of synaptic currents. To determine if depression in this system is synapse specific rather than general, we have also monitored synaptic transmission between pairs of cultured hippocampal neurons that are autaptically and reciprocally interconnected. We find that the change in synaptic strength is restricted to the synapses on the target neuron that were active during LTD induction. When viewed from the perspective of the presynaptic neuron, however, synapse specificity is partial rather than complete: synapses active during induction that were not on the target neuron were partially depressed. PMID:9448323

  11. Constitutive cylindrospermopsin pool size in Cylindrospermopsis raciborskii under different light and CO2 partial pressure conditions.

    PubMed

    Pierangelini, Mattia; Sinha, Rati; Willis, Anusuya; Burford, Michele A; Orr, Philip T; Beardall, John; Neilan, Brett A

    2015-05-01

    Cylindrospermopsin (CYN) and 7-deoxy-cylindrospermopsin (dCYN) are potent hepatotoxic alkaloids produced by numerous species of cyanobacteria, including the freshwater Cylindrospermopsis raciborskii. C. raciborskii is an invasive cyanobacterium, and the study of how environmental parameters drive CYN production has received significant interest from water managers and health authorities. Light and CO2 affect cell growth and physiology in photoautotrophs, and these are potential regulators of cyanotoxin biosynthesis. In this study, we investigated how light and CO2 affect CYN and dCYN pool size as well as the expression of the key genes, cyrA and cyrK, involved in CYN biosynthesis in a toxic C. raciborskii strain. For cells growing at different light intensities (10 and 100 μmol photons m(-2) s(-1)), we observed that the rate of CYN pool size production (μCYN) was coupled to the cell division rate (μc) during batch culture. This indicated that CYN pool size under our experimental conditions is constant and cell quotas of CYN (QCYN) and dCYN (QdCYN) are fixed. Moreover, a lack of correlation between expression of cyrA and total CYN cell quotas (QCYNs) suggests that the CYN biosynthesis is regulated posttranscriptionally. Under elevated CO2 (1,300 ppm), we observed minor effects on QCYN and no effects on expression of cyrA and cyrK. We conclude that the CYN pool size is constitutive and not affected by light and CO2 conditions. Thus, C. raciborskii bloom toxicity is determined by the absolute abundance of C. raciborskii cells within the water column and the relative abundance of toxic and nontoxic strains. PMID:25724956

  12. Swimming Pools.

    ERIC Educational Resources Information Center

    Ministry of Housing and Local Government, London (England).

    Technical and engineering data are set forth on the design and construction of swimming pools. Consideration is given to site selection, pool construction, the comparative merits of combining open air and enclosed pools, and alternative uses of the pool. Guidelines are presented regarding--(1) pool size and use, (2) locker and changing rooms, (3)…

  13. Increases in plasma pool size of lipoprotein components in copper-deficient hamsters

    SciTech Connect

    Al-Othman, A.A.; Rosenstein, F.; Lei, K.Y. )

    1991-03-15

    Twenty-four male Golden Syrian hamsters, were randomly assigned to 2 dietary copper (Cu) treatments; deficient and adequate. Reductions in weight gain, hematocrit and liver Cu as well as increases in heart weight and plasma volume were observed in CD hamsters after 7 weeks of treatment. Plasma very low (VLDL), low (LDL) and high (HDL) density lipoproteins were isolated by ultracentrifugation and Sepharose column chromatography. The percentage of total plasma cholesterol carried by LDL was increased from 20 to 24% but was reduced from 71 to 68% for HDL as a result of Cu deficiency. In LDL the % composition of triglycerides (TG) and phospholipids (PL) was increased by 25% but that of cholesterol was reduced by 13%. The % composition of protein was reduced 24% but that of TG was increased 18% in VLDL by Cu deficiency. Since plasma volume was increased 50% in CD hamsters, the data were expressed as the amount present in the plasma pool corrected for body weight. With the exceptions of smaller increased in VLDL protein and PL as well as the more than threefold increases in LDL TG and PL plasma pool size, the pool size for the rest of the lipoprotein components were increased about twofold in CD hamsters. The lipoprotein data further indicate that Cu deficiency increased the particle number of VLDL, LDL and HDL but enlarged the size of only VLDL and LDL.

  14. Changes in amino acid and nucleotide pools of Rhodospirillum rubrum during switch-off of nitrogenase activity initiated by NH4+ or darkness.

    PubMed Central

    Li, J D; Hu, C Z; Yoch, D C

    1987-01-01

    Amino acid and nucleotide pools were measured in nitrogenase-containing Rhodospirillum rubrum cultures during NH4+- or dark-induced inactivation (switch-off) of the Fe protein. A big increase in the glutamine pool size preceded NH4+ switch-off of nitrogenase activity, but the glutamine pool remained unchanged during dark switch-off. Furthermore, methionine sulfoximine had no effect on the rate of dark switch-off, suggesting that glutamine plays no role in this process. In the absence of NH4+ azaserine, an inhibitor of glutamate synthate, raised glutamine pool levels sufficiently to initiate switch-off in vivo. While added NH4+ substantially increased the size of the nucleotide pools in N-limited cells, the kinetics of nucleotide synthesis were all similar and followed (rather than preceded) Fe protein inactivation. Darkness had little effect on nucleotide pool sizes. Glutamate pool sizes were also found to be important in NH4+ switch-off because of the role of this molecule as a glutamine precursor. Much of the diversity reported in the observations on NH4+ switch-off appears to be due to variations in glutamate pool sizes prior to the NH4+ shock. The nitrogen nutritional background is an important factor in determining whether darkness initiates nitrogenase switch-off; however, no link has yet been established between this and NH4+ (glutamine) switch-off. Images PMID:2878918

  15. Size and age of the non structural carbohydrate pool in boreal trees

    NASA Astrophysics Data System (ADS)

    Czimczik, C. I.; Trumbore, S.

    2005-12-01

    Autotrophic respiration of trees is supposed to be closely linked to CO2 uptake by photosynthesis on a time scale of days. However, several studies have indicated that roots of boreal trees do not respired carbon (C) with a radiocarbon signature Δ14C similar to that of CO2 in the atmosphere, but C that is 3-4 years old. Also, estimates of gross primary productivity obtained by eddy covariance flux measurements do often not correlate with tree ring width (growth). Both these findings point to the presences of a large non-structural C (NSC) pool within the tree, mainly sugars and starches. The concentration of NSC in tree tissue is considered a measure of C shortage or surplus for growth. Studies indicate that the NSC pool in trees is usually large and relatively constant throughout the year, not affected by e.g. leaf flushing. While estimates of the size of the NSC pool are available for a number of trees from various ecosystems, estimated of its turnover time are lacking. We tested if our finding that boreal trees respire 3-4 year old C is an artifact resulting from the depletion of the NSC pool in excised roots over time. We incubated roots with a diameter of 2-4 mm while they were still attached to the tree, and excised roots after 3 hours, and 1 to 4 days. We sampled CO2 for Δ14C analysis of intact roots, freshly excised roots, and after 1 and 3 days. To obtain an estimate of the NSC pool size and its turnover time in roots of various diameter, we excised and incubated roots of 3 diameters: root hairs with mycorrhizal fungi, 2-4 mm, and 1-2 cm. We followed their respiration over the course of one full day. We will also compare the Δ14C of respired CO2 of freshly root hairs to that of the NSC in the roots. To obtain an estimate of the size and turnover of the whole tree NSC pool, we will measure the Δ14C of NSC in wood. Preliminary results indicate that CO2 fluxes were not correlated to temperature or the initial CO2 concentration in the chamber. While CO2

  16. Measuring size and composition of species pools: a comparison of dark diversity estimates.

    PubMed

    de Bello, Francesco; Fibich, Pavel; Zelený, David; Kopecký, Martin; Mudrák, Ondřej; Chytrý, Milan; Pyšek, Petr; Wild, Jan; Michalcová, Dana; Sádlo, Jiří; Šmilauer, Petr; Lepš, Jan; Pärtel, Meelis

    2016-06-01

    Ecological theory and biodiversity conservation have traditionally relied on the number of species recorded at a site, but it is agreed that site richness represents only a portion of the species that can inhabit particular ecological conditions, that is, the habitat-specific species pool. Knowledge of the species pool at different sites enables meaningful comparisons of biodiversity and provides insights into processes of biodiversity formation. Empirical studies, however, are limited due to conceptual and methodological difficulties in determining both the size and composition of the absent part of species pools, the so-called dark diversity. We used >50,000 vegetation plots from 18 types of habitats throughout the Czech Republic, most of which served as a training dataset and 1083 as a subset of test sites. These data were used to compare predicted results from three quantitative methods with those of previously published expert estimates based on species habitat preferences: (1) species co-occurrence based on Beals' smoothing approach; (2) species ecological requirements, with envelopes around community mean Ellenberg values; and (3) species distribution models, using species environmental niches modeled by Biomod software. Dark diversity estimates were compared at both plot and habitat levels, and each method was applied in different configurations. While there were some differences in the results obtained by different methods, particularly at the plot level, there was a clear convergence, especially at the habitat level. The better convergence at the habitat level reflects less variation in local environmental conditions, whereas variation at the plot level is an effect of each particular method. The co-occurrence agreed closest the expert estimate, followed by the method based on species ecological requirements. We conclude that several analytical methods can estimate species pools of given habitats. However, the strengths and weaknesses of different methods

  17. Expanded Cellular Amino Acid Pools Containing Phosphoserine, Phosphothreonine, and Phosphotyrosine

    PubMed Central

    2015-01-01

    Adding nonstandard amino acids to the genetic code of E. coli expands the chemical and biological functional space for proteins. This is accomplished with engineered, orthogonal aminoacyl-tRNA synthetase and tRNA pairs that require a nonstandard amino acid in sufficient intracellular quantities to support protein synthesis. While cotranslational insertion of phosphoserine into proteins has been accomplished, conditions that modulate intracellular phosphoamino acid concentrations are still poorly understood. Here we used genetic and metabolic engineering to increase the free intracellular levels of phosphoserine in E. coli. We show that deletion of the phosphoserine phosphatase serB elevates the intracellular levels of phosphoserine within ranges comparable to those of standard amino acids. These new conditions improved insertion of phosphoserine into recombinant proteins. Surprisingly, we also observed dramatic increases in intracellular levels of phosphothreonine and phosphotyrosine when WT cells were grown in LB with supplemented phosphothreonine and serB deficient cells were grown in low phosphate media with supplemented phosphotyrosine, respectively. These findings remove a major barrier for further expansion of the genetic code with additional phosphorylated amino acids. PMID:24646179

  18. Volatile disinfection byproducts resulting from chlorination of uric acid: implications for swimming pools.

    PubMed

    Lian, Lushi; E, Yue; Li, Jing; Blatchley, Ernest R

    2014-03-18

    Cyanogen chloride (CNCl) and trichloramine (NCl3) are important disinfection byproducts in chlorinated swimming pools. However, some unknowns exist regarding the precursors of their formation. In this study, uric acid is shown to be an efficient precursor to formation of CNCl and NCl3. The molar yields of CNCl and NCl3 were observed to be as high as 44% (pH = 6.0, chlorine/precursor molar ratio [Cl/P] = 6.4) and 108% (pH = 7.0, Cl/P = 30), respectively, both being strong functions of Cl/P, pH, and temperature. Analysis of swimming pool water samples, combined with the results of experiments involving chlorination of uric acid, and chlorination of body fluid analog mixtures, indicated that uric acid chlorination may account for a large fraction of CNCl formation in swimming pools. Moreover, given that uric acid introduction to pools is attributable to urination, a voluntary action for most swimmers, these findings indicate important benefits to pool water and air chemistry that could result from improved hygiene habits on the part of swimmers.

  19. Plasma non-esterified docosahexaenoic acid is the major pool supplying the brain.

    PubMed

    Chen, Chuck T; Kitson, Alex P; Hopperton, Kathryn E; Domenichiello, Anthony F; Trépanier, Marc-Olivier; Lin, Lauren E; Ermini, Leonardo; Post, Martin; Thies, Frank; Bazinet, Richard P

    2015-10-29

    Despite being critical for normal brain function, the pools that supply docosahexaenoic acid (DHA) to the brain are not agreed upon. Using multiple kinetic models in free-living adult rats, we first demonstrate that DHA uptake from the plasma non-esterified fatty acid (NEFA) pool predicts brain uptake of DHA upon oral administration, which enters the plasma NEFA pool as well as multiple plasma esterified pools. The rate of DHA loss by the brain is similar to the uptake from the plasma NEFA pool. Furthermore, upon acute iv administration, although more radiolabeled lysophosphatidylcholine (LPC)-DHA enters the brain than NEFA-DHA, this is due to the longer plasma half-life and exposure to the brain. Direct comparison of the uptake rate of LPC-DHA and NEFA-DHA demonstrates that uptake of NEFA-DHA into the brain is 10-fold greater than LPC-DHA. In conclusion, plasma NEFA-DHA is the major plasma pool supplying the brain.

  20. Plasma non-esterified docosahexaenoic acid is the major pool supplying the brain

    PubMed Central

    Chen, Chuck T.; Kitson, Alex P.; Hopperton, Kathryn E.; Domenichiello, Anthony F.; Trépanier, Marc-Olivier; Lin, Lauren E.; Ermini, Leonardo; Post, Martin; Thies, Frank; Bazinet, Richard P.

    2015-01-01

    Despite being critical for normal brain function, the pools that supply docosahexaenoic acid (DHA) to the brain are not agreed upon. Using multiple kinetic models in free-living adult rats, we first demonstrate that DHA uptake from the plasma non-esterified fatty acid (NEFA) pool predicts brain uptake of DHA upon oral administration, which enters the plasma NEFA pool as well as multiple plasma esterified pools. The rate of DHA loss by the brain is similar to the uptake from the plasma NEFA pool. Furthermore, upon acute iv administration, although more radiolabeled lysophosphatidylcholine (LPC)-DHA enters the brain than NEFA-DHA, this is due to the longer plasma half-life and exposure to the brain. Direct comparison of the uptake rate of LPC-DHA and NEFA-DHA demonstrates that uptake of NEFA-DHA into the brain is 10-fold greater than LPC-DHA. In conclusion, plasma NEFA-DHA is the major plasma pool supplying the brain. PMID:26511533

  1. The Bruchpilot cytomatrix determines the size of the readily releasable pool of synaptic vesicles.

    PubMed

    Matkovic, Tanja; Siebert, Matthias; Knoche, Elena; Depner, Harald; Mertel, Sara; Owald, David; Schmidt, Manuela; Thomas, Ulrich; Sickmann, Albert; Kamin, Dirk; Hell, Stefan W; Bürger, Jörg; Hollmann, Christina; Mielke, Thorsten; Wichmann, Carolin; Sigrist, Stephan J

    2013-08-19

    Synaptic vesicles (SVs) fuse at a specialized membrane domain called the active zone (AZ), covered by a conserved cytomatrix. How exactly cytomatrix components intersect with SV release remains insufficiently understood. We showed previously that loss of the Drosophila melanogaster ELKS family protein Bruchpilot (BRP) eliminates the cytomatrix (T bar) and declusters Ca(2+) channels. In this paper, we explored additional functions of the cytomatrix, starting with the biochemical identification of two BRP isoforms. Both isoforms alternated in a circular array and were important for proper T-bar formation. Basal transmission was decreased in isoform-specific mutants, which we attributed to a reduction in the size of the readily releasable pool (RRP) of SVs. We also found a corresponding reduction in the number of SVs docked close to the remaining cytomatrix. We propose that the macromolecular architecture created by the alternating pattern of the BRP isoforms determines the number of Ca(2+) channel-coupled SV release slots available per AZ and thereby sets the size of the RRP. PMID:23960145

  2. The Bruchpilot cytomatrix determines the size of the readily releasable pool of synaptic vesicles

    PubMed Central

    Matkovic, Tanja; Siebert, Matthias; Knoche, Elena; Depner, Harald; Mertel, Sara; Owald, David; Schmidt, Manuela; Thomas, Ulrich; Sickmann, Albert; Kamin, Dirk; Hell, Stefan W.; Bürger, Jörg; Hollmann, Christina; Mielke, Thorsten

    2013-01-01

    Synaptic vesicles (SVs) fuse at a specialized membrane domain called the active zone (AZ), covered by a conserved cytomatrix. How exactly cytomatrix components intersect with SV release remains insufficiently understood. We showed previously that loss of the Drosophila melanogaster ELKS family protein Bruchpilot (BRP) eliminates the cytomatrix (T bar) and declusters Ca2+ channels. In this paper, we explored additional functions of the cytomatrix, starting with the biochemical identification of two BRP isoforms. Both isoforms alternated in a circular array and were important for proper T-bar formation. Basal transmission was decreased in isoform-specific mutants, which we attributed to a reduction in the size of the readily releasable pool (RRP) of SVs. We also found a corresponding reduction in the number of SVs docked close to the remaining cytomatrix. We propose that the macromolecular architecture created by the alternating pattern of the BRP isoforms determines the number of Ca2+ channel-coupled SV release slots available per AZ and thereby sets the size of the RRP. PMID:23960145

  3. Changes in tissue free amino acid pools in growing chickens fed thermally treated vetch diets.

    PubMed

    Fernández-Fígares, I; Nieto, R; Aguilera, J F; Lachica, M

    2014-04-01

    A three-day assay was developed to evaluate the effect of autoclaving on protein quality of vetch as an alternative to classical growth methods. Male chickens (n = 10/diet) were given approximately isonitrogenous diets based on raw or autoclaved vetch for 3 days. Samples of plasma, muscle and liver were obtained for free amino acid analysis. Heating vetch depressed growth (11.9 vs. 23.2 g/d; p < 0.05). Plasma methionine and histidine increased (0.05 < p < 0.06), while gluconeogenic amino acids tended to decrease (p < 0.10) after heating. Muscle free amino acids did not change except for a trend to increased methionine (p = 0.06) in birds fed autoclaved vetch. In liver, most essential amino acids, glycine, proline and tyrosine increased markedly with heated vetch diet. Correlations between plasma and muscle free amino acids were poor compared with those between plasma and liver free amino acids. Liver free amino acid pool was more sensitive than muscle or plasma pool to amino acid inflow modifications after vetch heating.

  4. Amino Acid Pools and Metabolism During the Cell Division Cycle of Arginine-Grown Candida utilis

    PubMed Central

    Nurse, P.; Wiemken, A.

    1974-01-01

    Synchronous cultures obtained by isopycnic density gradient centrifugation are used to investigate amino acid metabolism during the cell division cycle of the food yeast Candida utilis. Isotopic labeling experiments demonstrate that the rates of uptake and catabolism of arginine, the sole source of nitrogen, double abruptly during the first half of the cycle, while the cells undergo bud expansion. This is accompanied by a doubling in rate of amino acid biosynthesis, and an accumulation of amino acids. The accumulation probably occurs within the storage pools of the vacuoles. Amino acids derived from protein degradation contribute little to this accumulation. For the remainder of the cell cycle, during cell separation and until the next bud initiation, the rates of uptake and catabolism of arginine and amino acid biosynthesis remain constant. Despite the abrupt doubling in the rate of formation of amino acid pools, their rate of utilization for macromolecular synthesis increases steadily throughout the cycle. The significance of this temporal organization of nitrogen source uptake and amino acid metabolism during the cell division cycle is discussed. Images PMID:4591945

  5. Total-body creatine pool size and skeletal muscle mass determination by creatine-(methyl-D3) dilution in rats.

    PubMed

    Stimpson, Stephen A; Turner, Scott M; Clifton, Lisa G; Poole, James C; Mohammed, Hussein A; Shearer, Todd W; Waitt, Greg M; Hagerty, Laura L; Remlinger, Katja S; Hellerstein, Marc K; Evans, William J

    2012-06-01

    There is currently no direct, facile method to determine total-body skeletal muscle mass for the diagnosis and treatment of skeletal muscle wasting conditions such as sarcopenia, cachexia, and disuse. We tested in rats the hypothesis that the enrichment of creatinine-(methyl-d(3)) (D(3)-creatinine) in urine after a defined oral tracer dose of D(3)-creatine can be used to determine creatine pool size and skeletal muscle mass. We determined 1) an oral tracer dose of D(3)-creatine that was completely bioavailable with minimal urinary spillage and sufficient enrichment in the body creatine pool for detection of D(3)-creatine in muscle and D(3)-creatinine in urine, and 2) the time to isotopic steady state. We used cross-sectional studies to compare total creatine pool size determined by the D(3)-creatine dilution method to lean body mass determined by independent methods. The tracer dose of D(3)-creatine (<1 mg/rat) was >99% bioavailable with 0.2-1.2% urinary spillage. Isotopic steady state was achieved within 24-48 h. Creatine pool size calculated from urinary D(3)-creatinine enrichment at 72 h significantly increased with muscle accrual in rat growth, significantly decreased with dexamethasone-induced skeletal muscle atrophy, was correlated with lean body mass (r = 0.9590; P < 0.0001), and corresponded to predicted total muscle mass. Total-body creatine pool size and skeletal muscle mass can thus be accurately and precisely determined by an orally delivered dose of D(3)-creatine followed by the measurement of D(3)-creatinine enrichment in a single urine sample and is promising as a noninvasive tool for the clinical determination of skeletal muscle mass. PMID:22422801

  6. Biologically active carbon filtration for haloacetic acid removal from swimming pool water.

    PubMed

    Tang, Hao L; Xie, Yuefeng F

    2016-01-15

    A biologically activate carbon (BAC) filter was continuously operated on site for the treatment of haloacetic acids (HAAs) in an outdoor swimming pool at an average empty bed contact time (EBCT) of 5.8 min. Results showed that BAC filtration was a viable technology for direct removal of HAAs from the pool water with a nominal efficiency of 57.7% by the filter while the chlorine residuals were 1.71 ± 0.90 mg/L during the study. THMs and TOC were not removed and thus were not considered as indicators of the effectiveness of BAC filtration. Increased EBCT in the range of 4.5 and 6.4 min led to improved HAA removal performance, which could be best fit by a logarithmic regression model. BAC filtration also affected the HAA speciation by removing more dichloroacetic acid (DCAA) than trichloroacetic acid (TCAA), resulting in a lower ratio of DCAA/TCAA in the filtered effluent. However, the observation of an overall constant ratio could be attributable to a complex formation and degradation mechanism occurring in swimming pools. PMID:26398451

  7. Biologically active carbon filtration for haloacetic acid removal from swimming pool water.

    PubMed

    Tang, Hao L; Xie, Yuefeng F

    2016-01-15

    A biologically activate carbon (BAC) filter was continuously operated on site for the treatment of haloacetic acids (HAAs) in an outdoor swimming pool at an average empty bed contact time (EBCT) of 5.8 min. Results showed that BAC filtration was a viable technology for direct removal of HAAs from the pool water with a nominal efficiency of 57.7% by the filter while the chlorine residuals were 1.71 ± 0.90 mg/L during the study. THMs and TOC were not removed and thus were not considered as indicators of the effectiveness of BAC filtration. Increased EBCT in the range of 4.5 and 6.4 min led to improved HAA removal performance, which could be best fit by a logarithmic regression model. BAC filtration also affected the HAA speciation by removing more dichloroacetic acid (DCAA) than trichloroacetic acid (TCAA), resulting in a lower ratio of DCAA/TCAA in the filtered effluent. However, the observation of an overall constant ratio could be attributable to a complex formation and degradation mechanism occurring in swimming pools.

  8. HPLC DETERMINATION OF CYANURIC ACID IN SWIMMING POOL WATERS USING PHENYL AND CONFIRMATORY POROUS GRAPHITIC CARBON COLUMNS

    EPA Science Inventory

    The chlorinated salts of cyanuric acid have found an important role in recreational swimming pool waters across the United States. Upon application to pool water, they can (1) release disinfectant chlorine or (2) stabilize the free available chlorine by acting as chlorine reserv...

  9. Distribution and elevated soil pools of mercury in an acidic subtropical forest of southwestern China.

    PubMed

    Zhou, Jun; Wang, Zhangwei; Zhang, Xiaoshan; Chen, Jian

    2015-07-01

    Tieshanping catchment in southwest China was supposed to a large pool of atmospheric mercury. This work was aimed to examine THg (total mercury) concentrations, pools and influence factors in the acidic forest. THg concentrations were highly elevated in the study area, which was significantly depended on TOM (total organic matter) concentrations and altitudinal elevation, whereas negatively correlated with soil pH. The pools of mercury accumulated in soils were correlated strongly with the stocks of TOM and altitude, ranged from 5.9 to 32 mg m(-2) and averaged 14.5 mg m(-2), indicating that the acidic forest was a great sink of atmospheric mercury in southwest China. THg concentrations in stream waters decreased with altitude increasing and regression analyses showed that soil/air exchange flux would be increased with the decrease of altitude. Present results suggest that elevation increasing decreases THg losses as low THg concentrations in runoffs and volatilization from soils. PMID:25836382

  10. Hepatic entrapment of esterified cholesterol drives continual expansion of whole body sterol pool in lysosomal acid lipase-deficient mice.

    PubMed

    Aqul, Amal; Lopez, Adam M; Posey, Kenneth S; Taylor, Anna M; Repa, Joyce J; Burns, Dennis K; Turley, Stephen D

    2014-10-15

    Cholesteryl ester storage disease (CESD) results from loss-of-function mutations in LIPA, the gene that encodes lysosomal acid lipase (LAL). Hepatomegaly and deposition of esterified cholesterol (EC) in multiple organs ensue. The present studies quantitated rates of synthesis, absorption, and disposition of cholesterol, and whole body cholesterol pool size in a mouse model of CESD. In 50-day-old lal(-/-) and matching lal(+/+) mice fed a low-cholesterol diet, whole animal cholesterol content equalled 210 and 50 mg, respectively, indicating that since birth the lal(-/-) mice sequestered cholesterol at an average rate of 3.2 mg·day(-1)·animal(-1). The proportion of the body sterol pool contained in the liver of the lal(-/-) mice was 64 vs. 6.3% in their lal(+/+) controls. EC concentrations in the liver, spleen, small intestine, and lungs of the lal(-/-) mice were elevated 100-, 35-, 15-, and 6-fold, respectively. In the lal(-/-) mice, whole liver cholesterol synthesis increased 10.2-fold, resulting in a 3.2-fold greater rate of whole animal sterol synthesis compared with their lal(+/+) controls. The rate of cholesterol synthesis in the lal(-/-) mice exceeded that in the lal(+/+) controls by 3.7 mg·day(-1)·animal(-1). Fractional cholesterol absorption and fecal bile acid excretion were unchanged in the lal(-/-) mice, but their rate of neutral sterol excretion was 59% higher than in their lal(+/+) controls. Thus, in this model, the continual expansion of the body sterol pool is driven by the synthesis of excess cholesterol, primarily in the liver. Despite the severity of their disease, the median life span of the lal(-/-) mice was 355 days.

  11. Pool size measurements facilitate the determination of fluxes at branching points in non-stationary metabolic flux analysis: the case of Arabidopsis thaliana.

    PubMed

    Heise, Robert; Fernie, Alisdair R; Stitt, Mark; Nikoloski, Zoran

    2015-01-01

    Pool size measurements are important for the estimation of absolute intracellular fluxes in particular scenarios based on data from heavy carbon isotope experiments. Recently, steady-state fluxes estimates were obtained for central carbon metabolism in an intact illuminated rosette of Arabidopsis thaliana grown photoautotrophically (Szecowka et al., 2013; Heise et al., 2014). Fluxes were estimated therein by integrating mass-spectrometric data of the dynamics of the unlabeled metabolic fraction, data on metabolic pool sizes, partitioning of metabolic pools between cellular compartments and estimates of photosynthetically inactive pools, with a simplified model of plant central carbon metabolism. However, the fluxes were determined by treating the pool sizes as fixed parameters. Here we investigated whether and, if so, to what extent the treatment of pool sizes as parameters to be optimized in three scenarios may affect the flux estimates. The results are discussed in terms of benchmark values for canonical pathways and reactions, including starch and sucrose synthesis as well as the ribulose-1,5-bisphosphate carboxylation and oxygenation reactions. In addition, we discuss pathways emerging from a divergent branch point for which pool sizes are required for flux estimation, irrespective of the computational approach used for the simulation of the observable labeling pattern. Therefore, our findings indicate the necessity for development of techniques for accurate pool size measurements to improve the quality of flux estimates from non-stationary flux estimates in intact plant cells in the absence of alternative flux measurements.

  12. Pool size measurements facilitate the determination of fluxes at branching points in non-stationary metabolic flux analysis: the case of Arabidopsis thaliana

    PubMed Central

    Heise, Robert; Fernie, Alisdair R.; Stitt, Mark; Nikoloski, Zoran

    2015-01-01

    Pool size measurements are important for the estimation of absolute intracellular fluxes in particular scenarios based on data from heavy carbon isotope experiments. Recently, steady-state fluxes estimates were obtained for central carbon metabolism in an intact illuminated rosette of Arabidopsis thaliana grown photoautotrophically (Szecowka et al., 2013; Heise et al., 2014). Fluxes were estimated therein by integrating mass-spectrometric data of the dynamics of the unlabeled metabolic fraction, data on metabolic pool sizes, partitioning of metabolic pools between cellular compartments and estimates of photosynthetically inactive pools, with a simplified model of plant central carbon metabolism. However, the fluxes were determined by treating the pool sizes as fixed parameters. Here we investigated whether and, if so, to what extent the treatment of pool sizes as parameters to be optimized in three scenarios may affect the flux estimates. The results are discussed in terms of benchmark values for canonical pathways and reactions, including starch and sucrose synthesis as well as the ribulose-1,5-bisphosphate carboxylation and oxygenation reactions. In addition, we discuss pathways emerging from a divergent branch point for which pool sizes are required for flux estimation, irrespective of the computational approach used for the simulation of the observable labeling pattern. Therefore, our findings indicate the necessity for development of techniques for accurate pool size measurements to improve the quality of flux estimates from non-stationary flux estimates in intact plant cells in the absence of alternative flux measurements. PMID:26082786

  13. Recent Advances in Substrate-Controlled Asymmetric Induction Derived from Chiral Pool α-Amino Acids for Natural Product Synthesis.

    PubMed

    Paek, Seung-Mann; Jeong, Myeonggyo; Jo, Jeyun; Heo, Yu Mi; Han, Young Taek; Yun, Hwayoung

    2016-07-21

    Chiral pool α-amino acids have been used as powerful tools for the total synthesis of structurally diverse natural products. Some common naturally occurring α-amino acids are readily available in both enantiomerically pure forms. The applications of the chiral pool in asymmetric synthesis can be categorized prudently as chiral sources, devices, and inducers. This review specifically examines recent advances in substrate-controlled asymmetric reactions induced by the chirality of α-amino acid templates in natural product synthesis research and related areas.

  14. RAPID ANALYSIS OF CYNANURIC ACID IN SWIMMING POOL WATERS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY USING POROUS GRAPHITIC CARBON COLUMN

    EPA Science Inventory

    An innovative approach is presented for reducing analysis times of cyanuric acid in swimming pool waters by high performance liquid chromatography (HPLC). The HPLC method exploits the unique selectivity of porous graphitic carbon (PGC) to fully resolve cyanuric acid from other p...

  15. Half a decade of mini-pool nucleic acid testing: Cost-effective way for improving blood safety in India

    PubMed Central

    Chandrashekar, Shivaram

    2014-01-01

    Background and Objectives: It is well established that Nucleic acid testing (NAT) reduces window phase of transfusion transmissible infections (TTI) and helps improve blood safety. NAT testing can be done individually or in pools. The objectives of this study were to determine the utility, feasibility and cost effectiveness of an in-house minipool-NAT(MP-NAT). Materials and Methods: Blood donors were screened by history, tested by ELISA and sero-negative samples were subjected to an in-house NAT by using reverse transcriptase-polymerase chain reaction (RT-PCR). Testing was done in mini-pools of size eight (8). Positive pools were repeated with individual samples. Results: During the study period of Oct 2005-Sept 2010 (5 years) all blood donors (n=53729) were screened by ELISA. Of which 469 (0.87%) were positive for HIV-1, HBV or HCV. Sero-negative samples (n=53260) were screened by in-house MP-NAT. HIV-NAT yield was 1/53260 (n=1) and HBV NAT yield (n=2) was 1/26630. Conclusion: NAT yield was lower than other India studies possibly due to the lower sero-reactivity amongst our donors. Nevertheless it intercepted 9 lives including the components prepared. The in-house assay met our objective of improving blood safety at nominal cost and showed that it is feasible to set up small molecular biology units in medium-large sized blood banks and deliver blood within 24-48 hours. The utility of NAT (NAT yield) will vary based on the donor population, the type of serological test used, the nature of kit employed and the sensitivity of NAT test used. The limitations of our in-house MP-NAT consisted of stringent sample preparation requirements, with labor and time involved. The benefits of our MP-NAT were that it acted as a second level of check for ELISA tests, was relatively inexpensive compared to ID-NAT and did not need sophisticated equipment. PMID:24678172

  16. The blue man: burn from muriatic acid combined with chlorinated paint in an adult pool construction worker.

    PubMed

    O'Cleireachain, Marc R; Macias, Luis H; Richey, Karen J; Pressman, Melissa A; Shirah, Gina R; Caruso, Daniel M; Foster, Kevin N; Matthews, Marc R

    2014-01-01

    Muriatic acid (hydrochloric acid), a common cleaning and resurfacing agent for concrete pools, can cause significant burn injuries. When coating a pool with chlorinated rubber-based paint, the pool surface is initially cleansed using 31.45% muriatic acid. Here we report a 50-year-old Hispanic male pool worker who, during the process of a pool resurfacing, experienced significant contact exposure to a combination of muriatic acid and blue chlorinated rubber-based paint. Confounding the clinical situation was the inability to efficiently remove the chemical secondary to the rubber-based nature of the paint. Additionally, vigorous attempts were made to remove the rubber paint using a variety of agents, including bacitracin, chlorhexidine soap, GOOP adhesive, and Johnson's baby oil. Resultant injuries were devastating fourth-degree burns requiring an immediate operative excision and amputation. Despite aggressive operative intervention and resuscitation, he continued to have severe metabolic derangements and ultimately succumbed to his injuries. We present our attempts at debridement and the system in place to manage patients with complex chemical burns.

  17. Incorporation of Ribonucleic Acid Bases into the Metabolic Pool and RNA of E. coli

    PubMed Central

    Buchwald, M.; Britten, R. J.

    1963-01-01

    Labeled cytosine, adenine, and guanine are rapidly incorporated by E. coli. A fraction of the radioactivity passes directly into RNA with very little delay. The remainder enters a pool before being incorporated into RNA. The fractions entering the pool and the time constants for equilibration of the specific activity of the pool are widely different for the four RNA bases. PMID:14016541

  18. Metabolic engineering of the purine biosynthetic pathway in Corynebacterium glutamicum results in increased intracellular pool sizes of IMP and hypoxanthine

    PubMed Central

    2012-01-01

    Background Purine nucleotides exhibit various functions in cellular metabolism. Besides serving as building blocks for nucleic acid synthesis, they participate in signaling pathways and energy metabolism. Further, IMP and GMP represent industrially relevant biotechnological products used as flavor enhancing additives in food industry. Therefore, this work aimed towards the accumulation of IMP applying targeted genetic engineering of Corynebacterium glutamicum. Results Blocking of the degrading reactions towards AMP and GMP lead to a 45-fold increased intracellular IMP pool of 22 μmol gCDW-1. Deletion of the pgi gene encoding glucose 6-phosphate isomerase in combination with the deactivated AMP and GMP generating reactions, however, resulted in significantly decreased IMP pools (13 μmol gCDW-1). Targeted metabolite profiling of the purine biosynthetic pathway further revealed a metabolite shift towards the formation of the corresponding nucleobase hypoxanthine (102 μmol gCDW-1) derived from IMP degradation. Conclusions The purine biosynthetic pathway is strongly interconnected with various parts of the central metabolism and therefore tightly controlled. However, deleting degrading reactions from IMP to AMP and GMP significantly increased intracellular IMP levels. Due to the complexity of this pathway further degradation from IMP to the corresponding nucleobase drastically increased suggesting additional targets for future strain optimization. PMID:23092390

  19. RAPID ANALYSIS OF CYANURIC ACID IN SWIMMING POOL WATERS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY USING POROUS GRAPHITIC CARBON

    EPA Science Inventory

    An innovative approach is presented for reducing analysis times of cynuric acid in swimming pool waters by high performance liquid chromatography (HPLC). The HPLC method exploits the unique selectivity of porous graphitic carbon (PGC) to fully resolve within 10 minutes cyanuric ...

  20. A pilot-scale study of Cryptosporidium-sized microsphere removals from swimming pools via sand filtration.

    PubMed

    Lu, Ping; Amburgey, James E

    2016-02-01

    Cryptosporidium species are the most common cause of gastrointestinal illness in treated recreational water venues. In order to protect public health during swimming, Cryptosporidium-sized microsphere removals by high-rate sand filtration with six coagulants were evaluated with a 5.5 m(3) pilot-scale swimming pool. A sand filter without coagulation removed 20-63% of Cryptosporidium-sized microspheres. Cryptosporidium-sized microsphere removals exceeded 98% by sand filtration with five of the six tested coagulants. Continuously feeding coagulants A, B, and F (i.e., organic polymers) led to coagulant accumulation in the system and decreased removals over time (<2 days). Coagulant E (polyaluminum chloride) consistently removed more than 90% of microspheres at 30 m/h while the removals dropped to approximately 50% at a filtration rate of 37 m/h. Coagulant C was a chitosan-based product that removed fewer microspheres compared with other products, <75%, under the studied conditions. Results indicated aluminum-based coagulants (coagulants D and E) had an overall performance advantage over the organic polymer based coagulants primarily in terms of their tendency not to accumulate in the water and cease to be effective at improving filter efficiency.

  1. A pilot-scale study of Cryptosporidium-sized microsphere removals from swimming pools via sand filtration.

    PubMed

    Lu, Ping; Amburgey, James E

    2016-02-01

    Cryptosporidium species are the most common cause of gastrointestinal illness in treated recreational water venues. In order to protect public health during swimming, Cryptosporidium-sized microsphere removals by high-rate sand filtration with six coagulants were evaluated with a 5.5 m(3) pilot-scale swimming pool. A sand filter without coagulation removed 20-63% of Cryptosporidium-sized microspheres. Cryptosporidium-sized microsphere removals exceeded 98% by sand filtration with five of the six tested coagulants. Continuously feeding coagulants A, B, and F (i.e., organic polymers) led to coagulant accumulation in the system and decreased removals over time (<2 days). Coagulant E (polyaluminum chloride) consistently removed more than 90% of microspheres at 30 m/h while the removals dropped to approximately 50% at a filtration rate of 37 m/h. Coagulant C was a chitosan-based product that removed fewer microspheres compared with other products, <75%, under the studied conditions. Results indicated aluminum-based coagulants (coagulants D and E) had an overall performance advantage over the organic polymer based coagulants primarily in terms of their tendency not to accumulate in the water and cease to be effective at improving filter efficiency. PMID:26837835

  2. Polyphosphoric acid capping radioactive/upconverting NaLuF4:Yb,Tm,153Sm nanoparticles for blood pool imaging in vivo.

    PubMed

    Peng, Juanjuan; Sun, Yun; Zhao, Lingzhi; Wu, Yongquan; Feng, Wei; Gao, Yanhong; Li, Fuyou

    2013-12-01

    Nanoparticles that circulate in the bloodstream for a prolonged period of time have important biomedicine applications. However, no example of lanthanide-based nanoparticles having a long-term circulation bloodstream has been reported to date. Herein, we report on difunctional radioactive and upconversion nanoparticles (UCNP) coated with polyphosphoric acid ligand, that is ethylenediamine tetramethylenephosphonic acid (EDTMP), for an application in single-photon emission computed tomography (SPECT) blood pool imaging. The structure, size and zeta-potential of the EDTMP-coated nanoparticles (EDTMP-UCNP) are verified using transmission electron microscopy and dynamic light scattering. Injection of radioisotope samarium-153-labeled EDTMP-UCNP (EDTMP-UCNP:(153)Sm) into mice reveal superior circulation time compared to control nanoparticles coated with citric acid (cit-UCNP:(153)Sm) and (153)Sm complex of EDTMP (EDTMP-(153)Sm). The mechanism for the extended circulation time may be attributed to the adhesion of EDTMP-UCNP on the membrane of red blood cells (RBCs). In vivo toxicity results show no toxicity of EDTMP-UCNP at the dose of 100 mg/kg, validating its safety as an agent for blood pool imaging. Our results provide a new strategy of nanoprobe for a long-term circulation bloodstream by introducing polyphosphoric acid as surface ligand.

  3. Changes in the Size of the Active Microbial Pool Explain Short-Term Soil Respiratory Responses to Temperature and Moisture.

    PubMed

    Salazar-Villegas, Alejandro; Blagodatskaya, Evgenia; Dukes, Jeffrey S

    2016-01-01

    abiotic conditions activated soil microorganisms. We conclude that soil respiratory responses to short-term changes in environmental conditions are better explained by changes in AMB than in TMB. These results suggest that decomposition models that explicitly represent microbial carbon pools should take into account the active microbial pool, and researchers should be cautious in comparing modeled microbial pool sizes with measurements of TMB. PMID:27148213

  4. Changes in the Size of the Active Microbial Pool Explain Short-Term Soil Respiratory Responses to Temperature and Moisture

    PubMed Central

    Salazar-Villegas, Alejandro; Blagodatskaya, Evgenia; Dukes, Jeffrey S.

    2016-01-01

    abiotic conditions activated soil microorganisms. We conclude that soil respiratory responses to short-term changes in environmental conditions are better explained by changes in AMB than in TMB. These results suggest that decomposition models that explicitly represent microbial carbon pools should take into account the active microbial pool, and researchers should be cautious in comparing modeled microbial pool sizes with measurements of TMB. PMID:27148213

  5. Changes in the Size of the Active Microbial Pool Explain Short-Term Soil Respiratory Responses to Temperature and Moisture.

    PubMed

    Salazar-Villegas, Alejandro; Blagodatskaya, Evgenia; Dukes, Jeffrey S

    2016-01-01

    abiotic conditions activated soil microorganisms. We conclude that soil respiratory responses to short-term changes in environmental conditions are better explained by changes in AMB than in TMB. These results suggest that decomposition models that explicitly represent microbial carbon pools should take into account the active microbial pool, and researchers should be cautious in comparing modeled microbial pool sizes with measurements of TMB.

  6. Ephemeroptera, Plecoptera, and Trichoptera on Isle Royale National Park, USA, compared to mainland species pool and size distribution

    PubMed Central

    DeWalt, R. Edward; South, Eric J.

    2015-01-01

    Abstract Extensive sampling for aquatic insects was conducted in the orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) (EPT) of Isle Royale National Park (ISRO), Michigan, United States of America, during summer 2013. The island was ice covered until 8,000 to 10,000 years ago and is isolated by 22–70 km distance from the mainland. Two hypotheses were examined: that ISRO EPT richness would be much reduced from the mainland, and that the species colonizing ISRO would be of smaller size than mainland, adults presumably using updrafts to bridge the distance from mainland sources. Data sets were developed for known mainland EPT species and size for those species. The first hypothesis was confirmed with the mainland species pool consisting of 417 EPT, while ISRO is known to support 73 species. Richness of EPT is directly related to the number of specimens examined. Small streams supported five EPT species, while 15–25 species were found in larger streams. Lakeshores had intermediate diversity. The second hypothesis was substantiated for stoneflies, but not for mayflies or caddisflies. Stoneflies apparently are poorer fliers than either of the other two orders. PMID:26692811

  7. Free amino acid pool of a sea anemone: exposure and recovery after an oil spill. [Sea Anemones

    SciTech Connect

    Kasschau, M.R.; Howard, C.L.

    1984-07-01

    A number of laboratory studies on marine invertebrates have shown changes in free amino acid (FAA) pools in response to various pollutants. During a nineteen-month field study to determine the effects of natural environmental parameters on the FAA pools to the Gulf Coast sea anemone, Bunodosoma cavernata, an oil tanker collision occurred about 8 miles off Galveston Island. The initial spill from the tanker Burma Agate occurred on November 1, 1979 with large leakages continuing for several weeks. There was no visible sign of oil on the first collection date 13 days after the spill, but 11 days later the anemones were covered with an oil sheen. As a result of this natural exposure to the oil, the authors decided to monitor the sea anemones for changes in the FAA pool during the oil exposure and recovery period.

  8. Metabolic and Transcriptional Analysis of Acid Stress in Lactococcus lactis, with a Focus on the Kinetics of Lactic Acid Pools

    PubMed Central

    Carvalho, Ana Lúcia; Turner, David L.; Fonseca, Luís L.; Solopova, Ana; Catarino, Teresa; Kuipers, Oscar P.; Voit, Eberhard O.; Neves, Ana Rute; Santos, Helena

    2013-01-01

    The effect of pH on the glucose metabolism of non-growing cells of L. lactis MG1363 was studied by in vivo NMR in the range 4.8 to 6.5. Immediate pH effects on glucose transporters and/or enzyme activities were distinguished from transcriptional/translational effects by using cells grown at the optimal pH of 6.5 or pre-adjusted to low pH by growth at 5.1. In cells grown at pH 5.1, glucose metabolism proceeds at a rate 35% higher than in non-adjusted cells at the same pH. Besides the upregulation of stress-related genes (such as dnaK and groEL), cells adjusted to low pH overexpressed H+-ATPase subunits as well as glycolytic genes. At sub-optimal pHs, the total intracellular pool of lactic acid reached approximately 500 mM in cells grown at optimal pH and about 700 mM in cells grown at pH 5.1. These high levels, together with good pH homeostasis (internal pH always above 6), imply intracellular accumulation of the ionized form of lactic acid (lactate anion), and the concomitant export of the equivalent protons. The average number, n, of protons exported with each lactate anion was determined directly from the kinetics of accumulation of intra- and extracellular lactic acid as monitored online by 13C-NMR. In cells non-adjusted to low pH, n varies between 2 and 1 during glucose consumption, suggesting an inhibitory effect of intracellular lactate on proton export. We confirmed that extracellular lactate did not affect the lactate: proton stoichiometry. In adjusted cells, n was lower and varied less, indicating a different mix of lactic acid exporters less affected by the high level of intracellular lactate. A qualitative model for pH effects and acid stress adaptation is proposed on the basis of these results. PMID:23844205

  9. Metabolic and transcriptional analysis of acid stress in Lactococcus lactis, with a focus on the kinetics of lactic acid pools.

    PubMed

    Carvalho, Ana Lúcia; Turner, David L; Fonseca, Luís L; Solopova, Ana; Catarino, Teresa; Kuipers, Oscar P; Voit, Eberhard O; Neves, Ana Rute; Santos, Helena

    2013-01-01

    The effect of pH on the glucose metabolism of non-growing cells of L. lactis MG1363 was studied by in vivo NMR in the range 4.8 to 6.5. Immediate pH effects on glucose transporters and/or enzyme activities were distinguished from transcriptional/translational effects by using cells grown at the optimal pH of 6.5 or pre-adjusted to low pH by growth at 5.1. In cells grown at pH 5.1, glucose metabolism proceeds at a rate 35% higher than in non-adjusted cells at the same pH. Besides the upregulation of stress-related genes (such as dnaK and groEL), cells adjusted to low pH overexpressed H(+)-ATPase subunits as well as glycolytic genes. At sub-optimal pHs, the total intracellular pool of lactic acid reached approximately 500 mM in cells grown at optimal pH and about 700 mM in cells grown at pH 5.1. These high levels, together with good pH homeostasis (internal pH always above 6), imply intracellular accumulation of the ionized form of lactic acid (lactate anion), and the concomitant export of the equivalent protons. The average number, n, of protons exported with each lactate anion was determined directly from the kinetics of accumulation of intra- and extracellular lactic acid as monitored online by (13)C-NMR. In cells non-adjusted to low pH, n varies between 2 and 1 during glucose consumption, suggesting an inhibitory effect of intracellular lactate on proton export. We confirmed that extracellular lactate did not affect the lactate: proton stoichiometry. In adjusted cells, n was lower and varied less, indicating a different mix of lactic acid exporters less affected by the high level of intracellular lactate. A qualitative model for pH effects and acid stress adaptation is proposed on the basis of these results.

  10. Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand.

    PubMed

    Hug, Katrin; Maher, William A; Stott, Matthew B; Krikowa, Frank; Foster, Simon; Moreau, John W

    2014-01-01

    Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with

  11. Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand

    PubMed Central

    Hug, Katrin; Maher, William A.; Stott, Matthew B.; Krikowa, Frank; Foster, Simon; Moreau, John W.

    2014-01-01

    Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55–75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18–25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with

  12. Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand.

    PubMed

    Hug, Katrin; Maher, William A; Stott, Matthew B; Krikowa, Frank; Foster, Simon; Moreau, John W

    2014-01-01

    Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with

  13. Endogenous Rho-kinase signaling maintains synaptic strength by stabilizing the size of the readily releasable pool of synaptic vesicles.

    PubMed

    González-Forero, David; Montero, Fernando; García-Morales, Victoria; Domínguez, Germán; Gómez-Pérez, Laura; García-Verdugo, José Manuel; Moreno-López, Bernardo

    2012-01-01

    Rho-associated kinase (ROCK) regulates neural cell migration, proliferation and survival, dendritic spine morphology, and axon guidance and regeneration. There is, however, little information about whether ROCK modulates the electrical activity and information processing of neuronal circuits. At neonatal stage, ROCKα is expressed in hypoglossal motoneurons (HMNs) and in their afferent inputs, whereas ROCKβ is found in synaptic terminals on HMNs, but not in their somata. Inhibition of endogenous ROCK activity in neonatal rat brainstem slices failed to modulate intrinsic excitability of HMNs, but strongly attenuated the strength of their glutamatergic and GABAergic synaptic inputs. The mechanism acts presynaptically to reduce evoked neurotransmitter release. ROCK inhibition increased myosin light chain (MLC) phosphorylation, which is known to trigger actomyosin contraction, and reduced the number of synaptic vesicles docked to active zones in excitatory boutons. Functional and ultrastructural changes induced by ROCK inhibition were fully prevented/reverted by MLC kinase (MLCK) inhibition. Furthermore, ROCK inhibition drastically reduced the phosphorylated form of p21-associated kinase (PAK), which directly inhibits MLCK. We conclude that endogenous ROCK activity is necessary for the normal performance of motor output commands, because it maintains afferent synaptic strength, by stabilizing the size of the readily releasable pool of synaptic vesicles. The mechanism of action involves a tonic inhibition of MLCK, presumably through PAK phosphorylation. This mechanism might be present in adults since unilateral microinjection of ROCK or MLCK inhibitors into the hypoglossal nucleus reduced or increased, respectively, whole XIIth nerve activity.

  14. Submicrometer-Sized Thermometer Particles Exploiting Selective Nucleic Acid Stability.

    PubMed

    Puddu, Michela; Mikutis, Gediminas; Stark, Wendelin J; Grass, Robert N

    2016-01-27

    Encapsulated nucleic acid selective damage quantification by real-time polymerase chain reaction is used as sensing mechanism to build a novel class of submicrometer size thermometer. Thanks to the high thermal and chemical stability, and the capability of storing the read accumulated thermal history, the sensor overcomes some of current limitations in small scale thermometry.

  15. Salinity and Nitrogen Effects on Photosynthesis, Ribulose-1,5-Bisphosphate Carboxylase and Metabolite Pool Sizes in Phaseolus vulgaris L. 1

    PubMed Central

    Seemann, Jeffrey R.; Sharkey, Thomas D.

    1986-01-01

    Salinity (100 millimolar NaCl) was found to reduce photosynthetic capacity independent of stomatal closure in Phaseolus vulgaris. This reduction was shown to be a consequence of a reduction in the efficiency of ribulose-1,5-bisphosphate (RuBP) carboxylase (RuBPCase) rather than a reduction in the leaf content of photosynthetic machinery. In control plants, photosynthesis became RuBP-limited at approximately 1.75 moles RuBP per mole 2-carboxyarabinitol bisphosphate binding sites. Salinization caused the RuBP pool size to reach this limiting value for CO2 fixation at much lower values of intercellular CO2. Plants grown at low nitrogen and ± NaCl became RuBP limited at similar RuBP pool sizes as the high nitrogen-grown plants. At limiting RuBP pool sizes and equal values of intercellular CO2 photosynthetic capacity of salt-stressed plants was less than control plants. This effect of salinity on RuBPCase activity could not be explained by deactivation of the enzyme or inhibitor synthesis. Thus, salinity reduced photosynthetic capacity by reducing both the RuBP pool size by an effect on RuBP regeneration capacity and RuBPCase activity by an unknown mechanism when RuBP was limiting. PMID:16665066

  16. Daily consumption of orange-fleshed sweet potato with added fat tends to increase total body vitamin A pool size in vitamin A depleted Bangladeshi women

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We assessed the affect of daily consumption of orange-fleshed sweet potato (OFSP), with or without added fat, on the total body vitamin A (VA) pool size of Bangladeshi women with low initial VA status. Women (n=120) received for 60d either 1) 0 µg RAE/d as boiled white-fleshed sweet potatoes (WFSP) ...

  17. Pooled Nucleic Acid Testing to Detect Antiretroviral Treatment Failure in Mexico

    PubMed Central

    Tilghman, Myres W.; Guerena, Don Diego; Licea, Alexei; Pérez-Santiago, Josué; Richman, Douglas D.; May, Susanne; Smith, Davey M.

    2010-01-01

    Background Similar to other resource-limited settings, cost restricts availability of viral load monitoring for most patients receiving antiretroviral therapy in Tijuana, Mexico. We evaluated if a pooling method could improve efficiency and reduce costs while maintaining accuracy. Methods We evaluated 700 patient blood plasma specimens at a reference laboratory in Tijuana for detectable viremia, individually and in 10 × 10 matrix pools. Thresholds for virologic failure were set at ≥500, ≥1000 and ≥1500 HIV RNA copies per milliliter. Detectable pools were deconvoluted using pre-set algorithms. Accuracy and efficiency of the pooling method were compared with individual testing. Quality assurance (QA) measures were evaluated after 1 matrix demonstrated low efficiency relative to individual testing. Results Twenty-two percent of the cohort had detectable HIV RNA (≥50 copies/mL). Pooling methods saved approximately one third of viral load assays over individual testing, while maintaining negative predictive values of >90% to detect samples with virologic failure (≥50 copies/mL). One matrix with low relative efficiency would have been detected earlier using the developed QA measures, but its exclusion would have only increased relative efficiency from 39% to 42%. These methods would have saved between $13,223 and $14,308 for monitoring this cohort. Conclusions Despite limited clinical data, high prevalence of detectable viral loads and a contaminated matrix, pooling greatly improved efficiency of virologic monitoring while maintaining accuracy. By improving cost-effectiveness, these methods could provide sustainability of virologic monitoring in resource-limited settings, and incorporation of developed QA measures will most likely maximize pooling efficiency in future uses. PMID:21124228

  18. Determination of haloacetic acids in swimming pool waters by membrane-protected micro-solid phase extraction.

    PubMed

    Nsubuga, Hakimu; Basheer, Chanbasha

    2013-11-01

    In this study, a simple and efficient extraction method for determining haloacetic acids (HAAs) in swimming pool waters has been developed. HAAs are toxic organic pollutants of disinfection origin most commonly detected in swimming pool and drinking waters at trace level concentrations. For the first time, a highly efficient sorbent was developed using rice husk and used for micro-solid phase extraction (μ-SPE) technique. To increase the extraction capability of rice husk silica, iron oxide was incorporated via sol-gel process. In μ-SPE device, the novel sorbent was packed and used for extraction of HAAs prior to analysis using ultra performance liquid chromatography-ultraviolet detection (UPLC-UV). Various extraction parameters were optimized to improve the extraction efficiency of μ-SPE. Under optimum conditions, linearity (coefficient of determination, r(2)≥0.991 over the concentration range of 1-150 μg/L), detection limits in the range of 0.001-0.092 μg/L, mean recoveries up to 110% with corresponding relative standard deviations of 2-7% (n=3) had been obtained. Finally, the method was applied to swimming pool water to evaluate its feasibility. The mean concentrations for HAAs from the pool waters were in the range of 6.8 and 48.6 μg/L which are far below the standard values set by United States Environmental Protection Agency. PMID:24075018

  19. N5-(1-carboxyethyl)-ornithine, a new amino acid from the intracellular pool of Streptococcus lactis.

    PubMed Central

    Thompson, J; Curtis, M A; Miller, S P

    1986-01-01

    Intracellular concentrations of amino acids were determined in cells of Streptococcus lactis 133 during growth in complex, spent, and chemically defined media. Glutamic and aspartic acids represented the major constituents of the amino acid pool. However, organisms grown in spent medium or in defined medium supplemented with ornithine also contained unusually high levels of two additional amino acids. One of these amino acids was ornithine. The second compound exhibited properties of a neutral amino acid by coelution with valine from the amino acid analyzer. The compound did not, however, comigrate with valine or any other standard amino acid by two-dimensional thin-layer chromatography. The unknown amino acid was purified by paper and thin-layer chromatography, and its molecular structure was determined by 1H and 13C nuclear magnetic resonance spectroscopy. This new amino acid was shown to be N5-(1-carboxyethyl)-ornithine. The 14C-labeled compound was formed by cells of S. lactis 133 during growth in spent medium or defined medium containing [14C]ornithine. Formation of the derivative by resting cells required ornithine and the presence of a metabolizable sugar. N5-(1-Carboxyethyl)-ornithine was synthesized chemically from both poly-S-ornithine and (2S)-N2-carbobenzyloxy-ornithine as a 1:1 mixture of two diastereomers. The physical and chemical properties of the amino acid purified from S. lactis 133 were identical to those of one of the synthetic diastereomers. The bis-N-trifluoroacetyl-di-n-butyl esters of the natural and synthetic compounds generated identical gas chromatography-mass spectrometry spectra. A mechanism is suggested for the in vivo synthesis of N5-(1-carboxyethyl)-ornithine, and the possible functions of this new amino acid are discussed. Images PMID:3090017

  20. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

    PubMed Central

    Igamberdiev, Abir U.; Eprintsev, Alexander T.

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium. PMID:27471516

  1. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants.

    PubMed

    Igamberdiev, Abir U; Eprintsev, Alexander T

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium. PMID:27471516

  2. Evaluation of prenucleic acid extraction for increasing sensitivity of detection of virus in bovine follicular fluid pools.

    PubMed

    Weber, M N; Galuppo, A G; Budaszewski, R F; Corbellini, A O; Mósena, A C S; Pinto, L D; Marques, L S; Rodrigues, J L; Canal, C W

    2013-04-01

    Bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BoHV-1), and bovine herpesvirus type 5 (BoHV-5) are major cattle pathogens that can be present in biological materials used in assisted reproduction biotechnologies. The aim of the present study was to increase the sensitivity of the polymerase chain reaction (PCR) for detection of BVDV, BoHV-1, and BoHV-5 in bovine follicular fluid (FF) collected during oocyte retrieval for in vitro embryo production. Ovaries were collected immediately after slaughter at a commercial abattoir, aspirated, and the 7336 samples of FF were pooled in 84 samples. Before testing the FF field samples, sensitivity of the protocol was determined using a prenucleic acid extraction procedure that was directly compared with standard RNA or DNA extraction protocols. The prenucleic acid extraction procedure increased sensitivity of reverse transcription (RT)-PCR for BVDV and nested PCR for BoHV-1 and BoHV-5 by 100 and 10 times, respectively. The 84 FF pools were assayed for BVDV, BoHV-1, and BoHV-5 using virus isolation and RT-PCR or nested PCR. Fourteen (16.7%) FF pools were positive for BVDV RNA, and one (1.2%) was positive for BoHV-1 DNA. Two of the BVDV RT-PCR positive samples and the one BoHV-1 PCR positive sample were also positive in cell culture, demonstrating that FF contained infectious viruses. In this study, the prenucleic acid extraction procedure increased the sensitivity of RT-PCR and PCR detection. This study highlighted the importance of assuring biosecurity by detecting the presence of viral pathogens in biological materials used during in vitro embryo production.

  3. Detection of a variable intracellular acid-labile carbon pool in Thalassiosira weissflogii (Heterokontophyta) and Emiliania huxleyi (Haptophyta) in response to changes in the seawater carbon system.

    PubMed

    Isensee, Kirsten; Erez, Jonathan; Stoll, Heather M

    2014-02-01

    Accumulation of an intracellular pool of carbon (C(i) pool) is one strategy by which marine algae overcome the low abundance of dissolved CO2 (CO2 (aq) ) in modern seawater. To identify the environmental conditions under which algae accumulate an acid-labile C(i) pool, we applied a (14) C pulse-chase method, used originally in dinoflagellates, to two new classes of algae, coccolithophorids and diatoms. This method measures the carbon accumulation inside the cells without altering the medium carbon chemistry or culture cell density. We found that the diatom Thalassiosira weissflogii [(Grunow) G. Fryxell & Hasle] and a calcifying strain of the coccolithophorid Emiliania huxleyi [(Lohmann) W. W. Hay & H. P. Mohler] develop significant acid-labile C(i) pools. C(i) pools are measureable in cells cultured in media with 2-30 µmol l(-1) CO2 (aq), corresponding to a medium pH of 8.6-7.9. The absolute C(i) pool was greater for the larger celled diatoms. For both algal classes, the C(i) pool became a negligible contributor to photosynthesis once CO2 (aq) exceeded 30 µmol l(-1) . Combining the (14) C pulse-chase method and (14) C disequilibrium method enabled us to assess whether E. huxleyi and T. weissflogii exhibited thresholds for foregoing accumulation of DIC or reduced the reliance on bicarbonate uptake with increasing CO2 (aq) . We showed that the C(i) pool decreases with higher CO2 :HCO3 (-) uptake rates.

  4. Injuries to cultivated BJA-B cells by ajoene, a garlic-derived natural compound: cell viability, glutathione metabolism, and pools of acidic amino acids.

    PubMed

    Scharfenberg, K; Ryll, T; Wagner, R; Wagner, K G

    1994-01-01

    Ajoene (4,5,9-trithiadodeca-1,6,11-triene-9-oxide), a garlic-derived natural compound, which had been shown to have cytostatic/cytotoxic properties, was tested with a B cell lymphoma-derived cell line (BJA-B cells) in order to elucidate its mechanism of cytotoxic action. Viability of the cells was determined by the Trypan blue exclusion test and the colorimetric tetrazolium (MTT) assay, whereas metabolic disturbance was evaluated by measuring the pools of reduced (GSH), oxidized glutathione (GSSG) and the acidic amino acids, Glu and Asp. Fast uptake of ajoene was accompanied by an immediate reduction of the GSH and increase in the GSSG levels. The extent of these changes, as well as the further development of the metabolite pools, depended on the ajoene dose per cell. At a sublethal ajoene dose the GSH and GSSG pools rose at the later stages to levels much higher than in the control experiment. Bleb formation at the cytoplasmic membrane was a further rapid phenomenon, although injuries detected by Trypan blue exclusion developed only at a later stage. The MTT assay, performed in a parallel experiment (48 h after ajoene addition), showed, however, that reduction of cell viability was established at the very beginning of ajoene exposure. Altogether, the action of ajoene strongly resembled oxidative stress (i.e., interference with SH homeostasis and its pleiotropic consequences to cell physiology and metabolism.

  5. Synthesis of customized petroleum-replica fuel molecules by targeted modification of free fatty acid pools in Escherichia coli

    PubMed Central

    Howard, Thomas P.; Middelhaufe, Sabine; Moore, Karen; Edner, Christoph; Kolak, Dagmara M.; Taylor, George N.; Parker, David A.; Lee, Rob; Smirnoff, Nicholas; Aves, Stephen J.; Love, John

    2013-01-01

    Biofuels are the most immediate, practical solution for mitigating dependence on fossil hydrocarbons, but current biofuels (alcohols and biodiesels) require significant downstream processing and are not fully compatible with modern, mass-market internal combustion engines. Rather, the ideal biofuels are structurally and chemically identical to the fossil fuels they seek to replace (i.e., aliphatic n- and iso-alkanes and -alkenes of various chain lengths). Here we report on production of such petroleum-replica hydrocarbons in Escherichia coli. The activity of the fatty acid (FA) reductase complex from Photorhabdus luminescens was coupled with aldehyde decarbonylase from Nostoc punctiforme to use free FAs as substrates for alkane biosynthesis. This combination of genes enabled rational alterations to hydrocarbon chain length (Cn) and the production of branched alkanes through upstream genetic and exogenous manipulations of the FA pool. Genetic components for targeted manipulation of the FA pool included expression of a thioesterase from Cinnamomum camphora (camphor) to alter alkane Cn and expression of the branched-chain α-keto acid dehydrogenase complex and β-keto acyl-acyl carrier protein synthase III from Bacillus subtilis to synthesize branched (iso-) alkanes. Rather than simply reconstituting existing metabolic routes to alkane production found in nature, these results demonstrate the ability to design and implement artificial molecular pathways for the production of renewable, industrially relevant fuel molecules. PMID:23610415

  6. Synthesis of customized petroleum-replica fuel molecules by targeted modification of free fatty acid pools in Escherichia coli.

    PubMed

    Howard, Thomas P; Middelhaufe, Sabine; Moore, Karen; Edner, Christoph; Kolak, Dagmara M; Taylor, George N; Parker, David A; Lee, Rob; Smirnoff, Nicholas; Aves, Stephen J; Love, John

    2013-05-01

    Biofuels are the most immediate, practical solution for mitigating dependence on fossil hydrocarbons, but current biofuels (alcohols and biodiesels) require significant downstream processing and are not fully compatible with modern, mass-market internal combustion engines. Rather, the ideal biofuels are structurally and chemically identical to the fossil fuels they seek to replace (i.e., aliphatic n- and iso-alkanes and -alkenes of various chain lengths). Here we report on production of such petroleum-replica hydrocarbons in Escherichia coli. The activity of the fatty acid (FA) reductase complex from Photorhabdus luminescens was coupled with aldehyde decarbonylase from Nostoc punctiforme to use free FAs as substrates for alkane biosynthesis. This combination of genes enabled rational alterations to hydrocarbon chain length (Cn) and the production of branched alkanes through upstream genetic and exogenous manipulations of the FA pool. Genetic components for targeted manipulation of the FA pool included expression of a thioesterase from Cinnamomum camphora (camphor) to alter alkane Cn and expression of the branched-chain α-keto acid dehydrogenase complex and β-keto acyl-acyl carrier protein synthase III from Bacillus subtilis to synthesize branched (iso-) alkanes. Rather than simply reconstituting existing metabolic routes to alkane production found in nature, these results demonstrate the ability to design and implement artificial molecular pathways for the production of renewable, industrially relevant fuel molecules.

  7. Synthesis of customized petroleum-replica fuel molecules by targeted modification of free fatty acid pools in Escherichia coli.

    PubMed

    Howard, Thomas P; Middelhaufe, Sabine; Moore, Karen; Edner, Christoph; Kolak, Dagmara M; Taylor, George N; Parker, David A; Lee, Rob; Smirnoff, Nicholas; Aves, Stephen J; Love, John

    2013-05-01

    Biofuels are the most immediate, practical solution for mitigating dependence on fossil hydrocarbons, but current biofuels (alcohols and biodiesels) require significant downstream processing and are not fully compatible with modern, mass-market internal combustion engines. Rather, the ideal biofuels are structurally and chemically identical to the fossil fuels they seek to replace (i.e., aliphatic n- and iso-alkanes and -alkenes of various chain lengths). Here we report on production of such petroleum-replica hydrocarbons in Escherichia coli. The activity of the fatty acid (FA) reductase complex from Photorhabdus luminescens was coupled with aldehyde decarbonylase from Nostoc punctiforme to use free FAs as substrates for alkane biosynthesis. This combination of genes enabled rational alterations to hydrocarbon chain length (Cn) and the production of branched alkanes through upstream genetic and exogenous manipulations of the FA pool. Genetic components for targeted manipulation of the FA pool included expression of a thioesterase from Cinnamomum camphora (camphor) to alter alkane Cn and expression of the branched-chain α-keto acid dehydrogenase complex and β-keto acyl-acyl carrier protein synthase III from Bacillus subtilis to synthesize branched (iso-) alkanes. Rather than simply reconstituting existing metabolic routes to alkane production found in nature, these results demonstrate the ability to design and implement artificial molecular pathways for the production of renewable, industrially relevant fuel molecules. PMID:23610415

  8. Effects of CO2 perturbation on phosphorus pool sizes and uptake in a mesocosm experiment during a low productive summer season in the northern Baltic Sea

    NASA Astrophysics Data System (ADS)

    Nausch, Monika; Bach, Lennart Thomas; Czerny, Jan; Goldstein, Josephine; Grossart, Hans-Peter; Hellemann, Dana; Hornick, Thomas; Achterberg, Eric Pieter; Schulz, Kai-Georg; Riebesell, Ulf

    2016-05-01

    Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in many aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. The phosphorus dynamic was followed in a CO2-manipulation mesocosm experiment in the Storfjärden (western Gulf of Finland, Baltic Sea) in summer 2012 and was also studied in the surrounding fjord water. In all mesocosms as well as in surface waters of Storfjärden, dissolved organic phosphorus (DOP) concentrations of 0.26 ± 0.03 and 0.23 ± 0.04 µmol L-1, respectively, formed the main fraction of the total P-pool (TP), whereas phosphate (PO4) constituted the lowest fraction with mean concentration of 0.15 ± 0.02 in the mesocosms and 0.17 ± 0.07 µmol L-1 in the fjord. Transformation of PO4 into DOP appeared to be the main pathway of PO4 turnover. About 82 % of PO4 was converted into DOP whereby only 18 % of PO4 was transformed into particulate phosphorus (PP). PO4 uptake rates measured in the mesocosms ranged between 0.6 and 3.9 nmol L-1 h-1. About 86 % of them was realized by the size fraction < 3 µm. Adenosine triphosphate (ATP) uptake revealed that additional P was supplied from organic compounds accounting for 25-27 % of P provided by PO4 only. CO2 additions did not cause significant changes in phosphorus (P) pool sizes, DOP composition, and uptake of PO4 and ATP when the whole study period was taken into account. However, significant short-term effects were observed for PO4 and PP pool sizes in CO2 treatments > 1000 µatm during periods when phytoplankton biomass increased. In addition, we found significant relationships (e.g., between PP and Chl a) in the untreated mesocosms which were not observed under high fCO2 conditions. Consequently, it can be hypothesized that the relationship between PP formation and phytoplankton growth changed with CO2 elevation

  9. NAD kinase regulates the size of the NADPH pool and insulin secretion in pancreatic β-cells.

    PubMed

    Gray, Joshua P; Alavian, Kambiz N; Jonas, Elizabeth A; Heart, Emma A

    2012-07-15

    NADPH is an important component of the antioxidant defense system and a proposed mediator in glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells. An increase in the NADPH/NADP(+) ratio has been reported to occur within minutes following the rise in glucose concentration in β-cells. However, 30 min following the increase in glucose, the total NADPH pool also increases through a mechanism not yet characterized. NAD kinase (NADK) catalyzes the de novo formation of NADP(+) by phosphorylation of NAD(+). NAD kinases have been shown to be essential for redox regulation, oxidative stress defense, and survival in bacteria and yeast. However, studies on NADK in eukaryotic cells are scarce, and the function of this enzyme has not been described in β-cells. We employed INS-1 832/13 cells, an insulin-secreting rat β-cell line, and isolated rodent islets to investigate the role of NADK in β-cell metabolic pathways. Adenoviral-mediated overexpression of NADK resulted in a two- to threefold increase in the total NADPH pool and NADPH/NADP(+) ratio, suggesting that NADP(+) formed by the NADK-catalyzed reaction is rapidly reduced to NADPH via cytosolic reductases. This increase in the NADPH pool was accompanied by an increase in GSIS in NADK-overexpressing cells. Furthermore, NADK overexpression protected β-cells against oxidative damage by the redox cycling agent menadione and reversed menadione-mediated inhibition of GSIS. Knockdown of NADK via shRNA exerted the opposite effect on all these parameters. These data suggest that NADK kinase regulates intracellular redox and affects insulin secretion and oxidative defense in the β-cell.

  10. NAD kinase regulates the size of the NADPH pool and insulin secretion in pancreatic β-cells.

    PubMed

    Gray, Joshua P; Alavian, Kambiz N; Jonas, Elizabeth A; Heart, Emma A

    2012-07-15

    NADPH is an important component of the antioxidant defense system and a proposed mediator in glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells. An increase in the NADPH/NADP(+) ratio has been reported to occur within minutes following the rise in glucose concentration in β-cells. However, 30 min following the increase in glucose, the total NADPH pool also increases through a mechanism not yet characterized. NAD kinase (NADK) catalyzes the de novo formation of NADP(+) by phosphorylation of NAD(+). NAD kinases have been shown to be essential for redox regulation, oxidative stress defense, and survival in bacteria and yeast. However, studies on NADK in eukaryotic cells are scarce, and the function of this enzyme has not been described in β-cells. We employed INS-1 832/13 cells, an insulin-secreting rat β-cell line, and isolated rodent islets to investigate the role of NADK in β-cell metabolic pathways. Adenoviral-mediated overexpression of NADK resulted in a two- to threefold increase in the total NADPH pool and NADPH/NADP(+) ratio, suggesting that NADP(+) formed by the NADK-catalyzed reaction is rapidly reduced to NADPH via cytosolic reductases. This increase in the NADPH pool was accompanied by an increase in GSIS in NADK-overexpressing cells. Furthermore, NADK overexpression protected β-cells against oxidative damage by the redox cycling agent menadione and reversed menadione-mediated inhibition of GSIS. Knockdown of NADK via shRNA exerted the opposite effect on all these parameters. These data suggest that NADK kinase regulates intracellular redox and affects insulin secretion and oxidative defense in the β-cell. PMID:22550069

  11. Distribution of Al-, Fe- and Mn-pools and their correlation in soils from two acid deposition small catchments in Hunan, China.

    PubMed

    Xue, Nandong; Seip, Hans Martin; Guo, Jinheng; Liao, Bohan; Zeng, Qingru

    2006-12-01

    Distribution of Al-, Fe- and Mn-pools was investigated in five forest soil profiles (consisting of four horizons) in each of two Hunan catchments (BLT and LKS) where acid deposition has been considered critical. Al- and Fe-pools were higher in BLT than those in LKS, but Mn-pools much lower in BLT. Mn-pools vary from topsoils to bottom soils, but there are different trends for different Mn speciation. Al- and Fe-pools, except amorphous Fe(ox), were positively correlated to contents of soil organic matter (OM) showed by the loss on ignition in the two catchments. Accumulation of Al- and Fe-pools may occur in the area where soil organic matter was enriched (e.g. in top soil and rhizosphere soil). However, no direct correlation is observed between Mn and OM. Acidic atmospheric deposition may affect transforming among speciations of Al-, Fe- and Mn-pools and leaching of soil Al, Fe and Mn through formation of soluble organo-metal dissolved Al which was potentially toxic, increased. There were significant correlations between Al-pools complexes or change of oxidation-reduction conditions. Mn(ex) (exchangeable Mn) and Mn(ox) (amorphous and organic Mn) were highly linearly correlation with soil pH values at LKS but at BLT. Under acid deposition, the availability of the nutrient Fe increased with the amount of dissolved Al, which was potentially toxic, in the two catchments. There are no significant correlations between Al(ex) (exchangeable Al) and Mn(ex), Fe(ex) (exchangeable Fe) and Mn(ex) in this work, indicating potentially toxic Mn increase seldom accompanying with Al increase in the two catchments.

  12. Diets high in resistant starch and arabinoxylan modulate digestion processes and SCFA pool size in the large intestine and faecal microbial composition in pigs.

    PubMed

    Nielsen, Tina S; Lærke, Helle N; Theil, Peter K; Sørensen, Jens F; Saarinen, Markku; Forssten, Sofia; Knudsen, Knud E Bach

    2014-12-14

    The effects of a high level of dietary fibre (DF) either as arabinoxylan (AX) or resistant starch (RS) on digestion processes, SCFA concentration and pool size in various intestinal segments and on the microbial composition in the faeces were studied in a model experiment with pigs. A total of thirty female pigs (body weight 63.1 (sem 4.4) kg) were fed a low-DF, high-fat Western-style control diet (WSD), an AX-rich diet (AXD) or a RS-rich diet (RSD) for 3 weeks. Diet significantly affected the digestibility of DM, protein, fat, NSP and NSP components, and the arabinose:xylose ratio, as well as the disappearance of NSP and AX in the large intestine. RS was mainly digested in the caecum. AX was digested at a slower rate than RS. The digesta from AXD-fed pigs passed from the ileum to the distal colon more than twice as fast as those from WSD-fed pigs, with those from RSD-fed pigs being intermediate (P< 0.001). AXD feeding resulted in a higher number of Faecalibacterium prausnitzii, Roseburia intestinalis, Blautia coccoides-Eubacterium rectale, Bifidobacterium spp. and Lactobacillus spp. in the faeces sampled at week 3 of the experimental period (P< 0.05). In the caecum, proximal and mid colon, AXD feeding resulted in a 3- to 5-fold higher pool size of butyrate compared with WSD feeding, with the RSD being intermediate (P <0.001). In conclusion, the RSD and AXD differently affected digestion processes compared with the WSD, and the AXD most efficiently shifted the microbial composition towards butyrogenic species in the faeces and increased the large-intestinal butyrate pool size.

  13. Effects of CO2 perturbation on phosphorus pool sizes and uptake in a mesocosm experiment during a low productive summer season in the northern Baltic Sea

    NASA Astrophysics Data System (ADS)

    Nausch, M.; Bach, L.; Czerny, J.; Goldstein, J.; Grossart, H. P.; Hellemann, D.; Hornick, T.; Achterberg, E.; Schulz, K.; Riebesell, U.

    2015-10-01

    Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in aquatic systems. The aim of our study was to analyze effects of elevated CO2 levels on phosphorus pool sizes and uptake. Therefore, we conducted a CO2-manipulation mesocosm experiment in the Storfjärden (western Gulf of Finland, Baltic Sea) in summer 2012. We compared the phosphorus dynamics in different mesocosm treatments but also studied them outside the mesocosms in the surrounding fjord water. In the mesocosms as well as in surface waters of Storfjärden, dissolved organic phosphorus (DOP) concentrations of 0.26 ± 0.03 and 0.23 ± 0.04 μmol L-1, respectively, formed the main fraction of the total P-pool (TP), whereas phosphate (PO4) constituted the lowest fraction with mean concentration of 0.15 ± 0.02 μmol L-1 and 0.17 ± 0.07 μmol L-1 in the mesocosms and in the fjord, respectively. Uptake of PO4 ranged between 0.6 and 3.9 nmol L-1 h-1 of which ~ 86 % (mesocosms) and ~ 72 % (fjord) were realized by the size fraction < 3 μm. Adenosine triphosphate (ATP) uptake revealed that additional P was supplied from organic compounds accounting for 25-27 % of P provided by PO4 only. CO2 additions did not cause significant changes in phosphorus (P) pool sizes, DOP composition, and uptake of PO4 and ATP when the whole study period was taken into account. About 18 % of PO4 was transformed into POP, whereby the major proportion (~ 82 %) was converted into DOP suggesting that the conversion of PO4 to DOP is the main pathway of the PO4 turnover. We observed that significant relationships (e.g., between POP and Chl a) in the untreated mesocosms vanished under increased fCO2 conditions. Consequently, it can be hypothesized that the relationship between POP formation and phytoplankton growth changed under elevated CO2 conditions. Significant short-term effects were observed for PO4 and particulate

  14. Rhizobins, a Group of Peptides in the Free-Amino-Acid Pool of the Soybean-Rhizobium System †

    PubMed Central

    Garay, Andrew S.; Ahlgren, Joy A.; Gonzalez, Mark A.; Stasney, Mark A.; Madtes, Paul C.

    1986-01-01

    Free-living Rhizobium (according to Bergey's Manual of Systematic Bacteriology, [1984, The Williams & Wilkins Co., Baltimore], Bradyrhizobium) japonicum was found to release a peptide into the nutrient media. Soybean nodules contained this peptide and exuded it into the soil. The name “rhizobin A” is suggested for this peptide. Nodules also contained another peptide, rhizobin B, as well as an unidentified, ninhydrin-positive compound, rhizobin C. The three peptides were confined to the free-amino-acid pool of the soluble fraction and eluted consecutively from a cation-exchange column. Rhizobin A was isolated in a highly purified form; its molecular mass was approximately 1,600 daltons as determined by Sephadex gel filtration and mass spectrometry. The amino-acid composition could be determined only approximately, because a long time was necessary for acid hydrolysis, possibly due to unusual linkages. The rhizobin concentration in soybean nodules continually increased during 50 days of growth, from 2 to approximately 400 μg/g (fresh weight). When combined nitrogen was added to nodulated soybean and subsequently removed, nitrogenase activity, nodulation, and nodule growth first decreased and then recovered. The relative amount of rhizobin A followed a similar pattern. Rhizobins were not detected in the roots, stems, and leaves of nodulated soybean plants. They were present in Lupinus nodules, but absent in alder nodules. PMID:16347004

  15. Fancd2 and p21 function independently in maintaining the size of hematopoietic stem and progenitor cell pool in mice.

    PubMed

    Zhang, Qing-Shuo; Watanabe-Smith, Kevin; Schubert, Kathryn; Major, Angela; Sheehan, Andrea M; Marquez-Loza, Laura; Newell, Amy E Hanlon; Benedetti, Eric; Joseph, Eric; Olson, Susan; Grompe, Markus

    2013-09-01

    Fanconi anemia patients suffer from progressive bone marrow failure. An overactive p53 response to DNA damage contributes to the progressive elimination of Fanconi anemia hematopoietic stem and progenitor cells (HSPC), and hence presents a potential target for therapeutic intervention. To investigate whether the cell cycle regulatory protein p21 is the primary mediator of the p53-dependent stem cell loss, p21/Fancd2 double-knockout mice were generated. Surprisingly double mutant mice displayed even more severe loss of HSPCs than Fancd2(-/-) single mutants. p21 deletion did not rescue the abnormal cell cycle profile and had no impact on the long-term repopulating potential of Fancd2(-/-) bone marrow cells. Collectively, our data indicate that p21 has an indispensable role in maintaining a normal HSPC pool and suggest that other p53-targeted factors, not p21, mediate the progressive elimination of HSPC in Fanconi anemia.

  16. The radial diffusivity and magnetization transfer pool size ratio are sensitive markers for demyelination in a rat model of type III multiple sclerosis (MS) lesions

    PubMed Central

    Janve, Vaibhav A.; Zu, Zhongliang; Yao, Song-Yi; Li, Ke; Zhang, Fang Lin; Wilson, Kevin; Ou, Xiawei; Does, Mark D.; Subramaniam, Sriram; Gochberg, Daniel F.

    2013-01-01

    Determining biophysical sensitivity and specificity of quantitative magnetic resonance imaging is essential to develop effective imaging metrics of neurodegeneration. Among these metrics apparent pool size ratio (PSR) from quantitative magnetization transfer (qMT) imaging and radial diffusivity (RD) from diffusion tensor imaging (DTI) are both known to relate to histological measure of myelin density and integrity. However their relative sensitivities towards quantitative myelin detection are unknown. In this study, we correlated high-resolution quantitative magnetic resonance imaging measures of subvoxel tissue structures with corresponding quantitative myelin histology in a lipopolysacharide (LPS) mediated animal model of MS. Specifically, we acquired quantitative magnetization transfer (qMT) and diffusion tensor imaging (DTI) metrics (on the same tissue sample) in an animal model system of type III oligodendrogliopathy which lacked prominent lymphocytic infiltration, a system that had not been previously examined with quantitative MRI. We find that the qMT measured apparent pool size ratio (PSR) showed the strongest correlation with a histological measure of myelin content. DTI measured RD showed the next strongest correlation, and other DTI and relaxation parameters (such as the longitudinal relaxation rate (R1f) or fractional anisotropy (FA)) showed considerably weaker correlations with myelin content. PMID:23481461

  17. Exchangeable and secondary mineral reactive pools of aluminium in coastal lowland acid sulfate soils.

    PubMed

    Yvanes-Giuliani, Yliane A M; Waite, T David; Collins, Richard N

    2014-07-01

    The use of coastal floodplain sulfidic sediments for agricultural activities has resulted in the environmental degradation of many areas worldwide. The generation of acidity and transport of aluminium (Al) and other metals to adjacent aquatic systems are the main causes of adverse effects. Here, a five-step sequential extraction procedure (SEP) was applied to 30 coastal lowland acid sulfate soils (CLASS) from north-eastern New South Wales, Australia. This enabled quantification of the proportion of aluminium present in 'water-soluble', 'exchangeable', 'organically-complexed', 'reducible iron(III) (oxyhydr)oxide/hydroxysulfate-incorporated' and 'amorphous Al mineral' fractions. The first three extractions represented an average of 5% of 'aqua regia' extractable Al and their cumulative concentrations were extremely high, reaching up to 4000 mg·kg(-1). Comparison of Al concentrations in the final two extractions indicated that 'amorphous Al minerals' are quantitatively a much more important sink for the removal of aqueous Al derived from the acidic weathering of these soils than reducible Fe(III) minerals. Correlations were observed between soil pH, dissolved and total organic carbon (DOC and TOC) and Al concentrations in organic carbon-rich CLASS soil horizons. These results suggest that complexation of Al by dissolved organic matter significantly increases soluble Al concentrations at pH values >5.0. As such, present land management practices would benefit with redefinition of an 'optimal' soil from pH ≥5.5 to ~4.8 for the preservation of aquatic environments adjacent to organic-rich CLASS where Al is the sole or principle inorganic contaminant of concern. Furthermore, it was observed that currently-accepted standard procedures (i.e. 1 M KCl extraction) to measure exchangeable Al concentrations in these types of soils severely underestimate exchangeable Al and a more accurate representation may be obtained through the use of 0.2 M CuCl2.

  18. Why to measure a broad range of city sizes? Analysis of globally pooled data of urban GHG measurements for sustainability

    NASA Astrophysics Data System (ADS)

    Rybski, Diego; Sterzel, Till; Reusser, Dominik E.; Fichter, Christina; Kropp, Jürgen P.

    2013-04-01

    We have assembled a database of urban GHG emissions from various published sources, including about 200 cities globally. Analyzing this CO2 emission inventory from multiple countries we find power-law relations between the emissions and city size, measured in population. The results suggest that in developing countries large cities emit more CO2 per capita compared to small cities, i.e. they tend to comprise super-linear correlations. For developed countries the results suggest the opposite, i.e. linear or sub-linear correlations, implying better efficiency of large cities. We derive how the total emissions of an entire country relate with the power-law correlations and find that the size of the most populated city is dominating in the case of linear and super-linear correlations, while a transition occurs to sub-linear correlations, where the size of the largest city has no influence. It is important to further substantiate an overview of city emission inventories across a broad range of city sizes and types to further clarify the complex relationships between cities and GHG emissions. On the one hand, we propose a minimum set of meta-information to be reported together with the emission inventories, e.g. for determining comparability among inventories. On the other hand, we propose to fill evident gaps with respect to regions (e.g. sub-Saharan African and South American cities) and types of cities (e.g. small medium and low-income country cities) to allow for a better global overview of city sizes, income, and emissions. We conclude that from the climate change mitigation point of view, urbanization is desirable in developed countries and should be avoided in developing countries, if effinciency increasing mechanisms can not be established. More data acquisition is needed to support our empirical findings.

  19. Nicotine enhancement of dopamine release by a calcium-dependent increase in the size of the readily releasable pool of synaptic vesicles.

    PubMed

    Turner, Timothy J

    2004-12-15

    A major factor underlying compulsive tobacco use is nicotine-induced modulation of dopamine release in the mesolimbic reward pathway (Wise and Rompre, 1989). An established biochemical mechanism for nicotine-enhanced dopamine release is by activating presynaptic nicotinic acetylcholine receptors (nAChRs) (Wonnacott, 1997). Prolonged application of 10(-7) to 10(-5) m nicotine to striatal synaptosomes promoted a sustained efflux of [3H]dopamine. This nicotine effect was mediated by non-alpha7 nAChRs, because it was blocked by 5 mum mecamylamine but was resistant to 100 nm alpha-bungarotoxin (alphaBgTx). Dopamine release was diminished by omitting Na+ or by applying peptide calcium channel blockers, indicating that nAChRs trigger release by depolarizing the nerve terminals. However, because alpha7 receptors rapidly desensitize in the continuous presence of agonists, a repetitive stimulation protocol was used to evaluate the possible significance of desensitization. This protocol produced a transient increase in [3H]dopamine released by depolarization and a significant increase in the response to hypertonic solutions that measure the size of the readily releasable pool (RRP) of synaptic vesicles. The nicotine-induced increase in the size of the readily releasable pool was blocked by alphaBgTx and by the calmodulin antagonist calmidazolium, suggesting that Ca2+ entry through alpha7 nAChRs specifically enhances synaptic vesicle mobilization at dopamine terminals. Thus, nicotine enhances dopamine release by two complementary actions mediated by discrete nAChR subtypes and suggest that the alpha7 nAChR-mediated pathway is tightly and specifically coupled to refilling of the RRP of vesicles in dopamine terminals.

  20. Does Valproic Acid or Levetiracetam Improve Survival in Glioblastoma? A Pooled Analysis of Prospective Clinical Trials in Newly Diagnosed Glioblastoma

    PubMed Central

    Happold, Caroline; Gorlia, Thierry; Chinot, Olivier; Gilbert, Mark R.; Nabors, L. Burt; Wick, Wolfgang; Pugh, Stephanie L.; Hegi, Monika; Cloughesy, Timothy; Roth, Patrick; Reardon, David A.; Perry, James R.; Mehta, Minesh P.; Stupp, Roger

    2016-01-01

    Purpose Symptomatic epilepsy is a common complication of glioblastoma and requires pharmacotherapy. Several uncontrolled retrospective case series and a post hoc analysis of the registration trial for temozolomide indicated an association between valproic acid (VPA) use and improved survival outcomes in patients with newly diagnosed glioblastoma. Patients and Methods To confirm the hypothesis suggested above, a combined analysis of survival association of antiepileptic drug use at the start of chemoradiotherapy with temozolomide was performed in the pooled patient cohort (n = 1,869) of four contemporary randomized clinical trials in newly diagnosed glioblastoma: AVAGlio (Avastin in Glioblastoma; NCT00943826), CENTRIC (Cilengitide, Temozolomide, and Radiation Therapy in Treating Patients With Newly Diagnosed Glioblastoma and Methylated Gene Promoter Status; NCT00689221), CORE (Cilengitide, Temozolomide, and Radiation Therapy in Treating Patients With Newly Diagnosed Glioblastoma and Unmethylated Gene Promoter Status; NCT00813943), and Radiation Therapy Oncology Group 0825 (NCT00884741). Progression-free survival (PFS) and overall survival (OS) were compared between: (1) any VPA use and no VPA use at baseline or (2) VPA use both at start of and still after chemoradiotherapy. Results of Cox regression models stratified by trial and adjusted for baseline prognostic factors were analyzed. The same analyses were performed with levetiracetam (LEV). Results VPA use at start of chemoradiotherapy was not associated with improved PFS or OS compared with all other patients pooled (PFS: hazard ratio [HR], 0.91; 95% CI, 0.77 to 1.07; P = .241; OS: HR, 0.96; 95% CI, 0.80 to 1.15; P = .633). Furthermore, PFS and OS of patients taking VPA both at start of and still after chemoradiotherapy were not different from those without antiepileptic drug use at both time points (PFS: HR, 0.92; 95% CI, 0.74 to 1.15; P = .467; OS: HR, 1.10; 95% CI, 0.86 to 1.40; P = .440). Similarly, no

  1. Pool Purification

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Caribbean Clear, Inc. used NASA's silver ion technology as a basis for its automatic pool purifier. System offers alternative approach to conventional purification chemicals. Caribbean Clear's principal markets are swimming pool owners who want to eliminate chlorine and bromine. Purifiers in Caribbean Clear System are same silver ions used in Apollo System to kill bacteria, plus copper ions to kill algae. They produce spa or pool water that exceeds EPA Standards for drinking water.

  2. Size-controlled dissolution of silver nanoparticles at neutral and acidic pH conditions: kinetics and size changes.

    PubMed

    Peretyazhko, Tanya S; Zhang, Qingbo; Colvin, Vicki L

    2014-10-21

    Silver nanoparticles (Ag(NP)) are widely utilized in increasing number of medical and consumer products due to their antibacterial properties. Once released to aquatic system, Ag(NP) undergoes oxidative dissolution leading to production of toxic Ag(+). Dissolved Ag(+) can have a severe impact on various organisms, including indigenous microbial communities, fungi, alga, plants, vertebrates, invertebrates, and human cells. Therefore, it is important to investigate fate of Ag(NP) and determine physico-chemicals parameters that control Ag(NP) behavior in the natural environment. Nanoparticle size might have a dominant effect on Ag(NP) dissolution in natural waters. In this work, we investigated size-dependent dissolution of AgNP exposed to ultrapure deionized water (pH ≈ 7) and acetic acid (pH 3) and determined changes in nanoparticle size after dissolution. Silver nanoparticles stabilized by thiol functionalized methoxyl polyethylene glycol (PEGSH) of 6 nm (Ag(NP_)6), 9 nm (Ag(NP_)9), 13 nm (Ag(NP_)13), and 70 nm (Ag(NP_)70) were prepared. The results of dissolution experiments showed that the extent of AgNP dissolution in acetic acid was larger than in water. Solubility of Ag(NP) increased with the size decrease and followed the order Ag(NP_)6 > Ag(NP_)9 > Ag(NP_)13 > Ag(NP_)70 in both water and acetic acid. Transmission electron microscopy (TEM) was applied to characterize changes in size and morphology of the AgNP after dissolution in water. Analysis of Ag(NP) by TEM revealed that the particle morphology did not change during dissolution. The particles remained approximately spherical in shape, and no visible aggregation was observed in the samples. TEM analysis also demonstrated that Ag(NP_)6, Ag(NP_)9, and Ag(NP_)13 increased in size after dissolution likely due to Ostwald ripening. PMID:25265014

  3. CHARACTERIZATION OF HUMIC ACID SIZE FRACTIONS BY SEC AND MALS (R822832)

    EPA Science Inventory

    Latahco silt-loam humic acid was separated on a preparatory scale by size exclusion chromatography (SEC) on a gravity-fed Sepharose column. Four fractions from this separation were collected and further analyzed, along with whole humic acid, by high-performance SEC coupled with a...

  4. RIM1 and RIM2 redundantly determine Ca2+ channel density and readily releasable pool size at a large hindbrain synapse.

    PubMed

    Han, Yunyun; Babai, Norbert; Kaeser, Pascal; Südhof, Thomas C; Schneggenburger, Ralf

    2015-01-01

    The localization and density of voltage-gated Ca(2+) channels at active zones are essential for the amount and kinetics of transmitter release at synapses. RIM proteins are scaffolding proteins at the active zone that bind to several other presynaptic proteins, including voltage-gated Ca(2+) channel α-subunits. The long isoforms of RIM proteins, which contain NH2-terminal Rab3- and Munc13-interacting domains, as well as a central PDZ domain and two COOH-terminal C2 domains, are encoded by two genes, Rim1 and Rim2. Here, we used the ideal accessibility of the large calyx of Held synapse for direct presynaptic electrophysiology to investigate whether the two Rim genes have redundant, or separate, functions in determining the presynaptic Ca(2+) channel density, and the size of a readily releasable vesicle pool (RRP). Quantitative PCR showed that cochlear nucleus neurons, which include calyx of Held generating neurons, express both RIM1 and RIM2. Conditional genetic inactivation of RIM2 at the calyx of Held led to a subtle reduction in presynaptic Ca(2+) current density, whereas deletion of RIM1 was ineffective. The release efficiency of brief presynaptic Ca(2+) "tail" currents and the RRP were unaffected in conditional single RIM1 and RIM2 knockout (KO) mice, whereas both parameters were strongly reduced in RIM1/2 double KO mice. Thus, despite a somewhat more decisive role for RIM2 in determining presynaptic Ca(2+) channel density, RIM1 and RIM2 can overall replace each other's presynaptic functions at a large relay synapse in the hindbrain, the calyx of Held.

  5. Particle size distribution of hydrocyanic acid in gari, a cassava-based product.

    PubMed

    Maduagwu, E N; Fafunso, M

    1980-12-01

    A reciprocal relationship was observed between the cyanide content of gari and particle size. Hydrocyanic acid (HCN) content was positively correlated (r = 0.62) with sugar content but the correlation with starch content was poor (r = 0.33). From both the nutritional and toxicological standpoints, it would appear that larger particles size in gari is beneficial.

  6. Stable nitrogen isotopes in essential versus non-essential amino acids of different plankton size fractions.

    PubMed

    Loick, Natalie; Gehre, Matthias; Voss, Maren

    2007-12-01

    The stable nitrogen isotope values (delta(15)N) of the essential amino acid (EAA) leucine and the delta(15)N values of six non-essential amino acids (NEAAs) from plankton size fractions from the South China Sea (SCS) were analysed. Data from the SCS were collected during two cruises in July 2003 and 2004 onboard of RV Nghien Cuu Bien. The delta(15)N values of alanine, aspartic acid, glutamic acid and leucine increased with size at all sites. The delta(15)N of glycine did not increase with size, the delta(15)N of tyrosine increased with size only at offshore stations and the delta(15)N of proline increased with size only at inshore stations. We found highly significant correlations between the delta(15)N ratios of leucine to the delta(15)N ratios of glutamic acid, proline, alanine, tyrosine and aspartic acid at oligotrophic sites of enhanced nitrogen fixation. In contrast thereto these correlations were less distinct or absent at more eutrophic sites of low nitrogen fixation. A comparison with an independent data set from the tropical North Atlantic revealed intriguing similar patterns. We interpret these patterns as result of the connected metabolism of EAA and NEAA in zooplankton at sites of nitrogen limitation.

  7. Demands of eicosapentaenoic acid (EPA) in Daphnia: are they dependent on body size?

    PubMed

    Sikora, Anna B; Petzoldt, Thomas; Dawidowicz, Piotr; von Elert, Eric

    2016-10-01

    Fatty acids contribute to the nutritional quality of the phytoplankton and, thus, play an important role in Daphnia nutrition. One of the polyunsaturated fatty acids (PUFAs)--eicosapentaenoic acid (EPA)--has been shown to predict carbon transfer between primary producers and consumers in lakes, suggesting that EPA limitation of Daphnia in nature is widespread. Although the demand for EPA must be covered by the diet, the demand of EPA in Daphnia that differ in body size has not been addressed yet. Here, we hypothesize that the demand for EPA in Daphnia is size-dependent and that bigger species have a higher EPA demand. To elucidate this, a growth experiment was conducted in which at 20 °C three Daphnia taxa (small-sized D. longispina complex, medium-sized D. pulicaria, and large-bodied D. magna) were fed Synechococcus elongatus supplemented with cholesterol and increasing concentrations of EPA. In addition, fatty acid analyses of Daphnia were performed. Our results show that the saturation threshold for EPA-dependent growth increased with increasing body size. This increase in thresholds with body size may provide another mechanism contributing to the prevalence of small-bodied cladocera in warm habitats and to the midsummer decline of large cladocera in eutrophic water bodies. PMID:27345442

  8. Absorbed zinc and exchangeable zinc pool size are greater in Pakistani infants receiving traditional complementary foods with zinc-fortified micronutrient powder.

    PubMed

    Ariff, Shabina; Krebs, Nancy F; Soofi, Sajid; Westcott, Jamie; Bhatti, Zaid; Tabassum, Farhana; Bhutta, Zulfiqar A

    2014-01-01

    Adequacy of zinc intake from breast milk alone becomes marginal in relation to infant requirements by around 6 mo of age. Simple and cost-effective strategies are needed at the population level to ensure adequate intakes of zinc in infants and toddlers in populations at risk of zinc deficiency. We determined the amount of absorbed zinc (AZ) from a micronutrient powder (MNP) without and with 10 mg of zinc (MNP+Zn) added to local complementary foods used in Pakistan and the impact on the exchangeable zinc pool (EZP) size. As a nested study within a large, prospective, cluster randomized trial, 6-mo-old infants were randomly assigned to receive MNP or MNP+Zn. Stable isotope methodology was applied after ∼3 and 9 mo of use to measure AZ from MNP-fortified test meals of rice-lentils (khitchri) and EZP. Nineteen infants per group completed the first metabolic studies and 14 and 17 infants in the MNP and MNP+Zn groups, respectively, completed the follow-up studies. AZs were (mean ± SD) 0.1 ± 0.1 and 1.2 ± 0.5 mg at the first point for the MNP and MNP+Zn groups, respectively (P < 0.001); results were nearly identical at the follow-up measurement. EZP did not differ between groups at the first measurement but was less in the MNP group (3.7 ± 0.6 mg/kg) than in the MNP+Zn group (4.5 ± 1.0 mg/kg) at the second measurement (P = 0.01). These data confirm that the MNP+Zn in khitchri were well absorbed and after 1 y of home fortification, zinc status assessed by EZP was significantly better for the MNP+Zn group. Additional field studies may be necessary to ascertain the adequacy of this dose for infants at high risk of deficiency. This trial was registered at ClinicalTrials.gov as NCT00705445.

  9. hERG blocking potential of acids and zwitterions characterized by three thresholds for acidity, size and reactivity.

    PubMed

    Nikolov, Nikolai G; Dybdahl, Marianne; Jónsdóttir, Svava Ó; Wedebye, Eva B

    2014-11-01

    Ionization is a key factor in hERG K(+) channel blocking, and acids and zwitterions are known to be less probable hERG blockers than bases and neutral compounds. However, a considerable number of acidic compounds block hERG, and the physico-chemical attributes which discriminate acidic blockers from acidic non-blockers have not been fully elucidated. We propose a rule for prediction of hERG blocking by acids and zwitterionic ampholytes based on thresholds for only three descriptors related to acidity, size and reactivity. The training set of 153 acids and zwitterionic ampholytes was predicted with a concordance of 91% by a decision tree based on the rule. Two external validations were performed with sets of 35 and 48 observations, respectively, both showing concordances of 91%. In addition, a global QSAR model of hERG blocking was constructed based on a large diverse training set of 1374 chemicals covering all ionization classes, externally validated showing high predictivity and compared to the decision tree. The decision tree was found to be superior for the acids and zwitterionic ampholytes classes.

  10. 76 FR 72950 - Draft Guidance for Industry: Use of Nucleic Acid Tests on Pooled and Individual Samples From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-28

    ... (HBV) deoxyribonucleic acid (DNA) and recommendations for product testing and disposition, donor...- licensed NAT to screen blood donors for HBV DNA. FDA is also providing these blood establishments...

  11. Dietary fatty acid enrichment increases egg size and quality of yellow seahorse Hippocampus kuda.

    PubMed

    Saavedra, M; Masdeu, M; Hale, P; Sibbons, C M; Holt, W V

    2014-02-01

    Seahorses populations in the wild have been declining and to restore them a better knowledge of seahorse reproduction is required. This study examines the effect of dietary quality on seahorse fecundity and egg quality. Two different diets were tested with Hippocampus kuda females: frozen mysis (control) and frozen mysis enriched with a liposome spray containing essential fatty acids. Diets were given to females (two groups of five) over a seven week period. After this period, males (fed the control diet) and females were paired and the eggs dropped by the females were collected. Fatty acid profile were analysed and eggs were counted and measured. Results showed that females fed on enriched mysis had larger eggs and that these had a higher content of total polyunsaturated fatty acids. The size of the egg was especially affected in the first spawn, where egg size for females fed the enriched diet was significantly higher than the egg size from control females. This effect was reduced in the following spawning where no significant differences were found. Egg size is an important quality descriptor as seahorse juveniles originating from smaller eggs and/or eggs of poor quality will have less chances of overcoming adverse conditions in the wild and consequently have lower survival and growth rates. This study shows that enriching frozen mysis with polyunsaturated fatty acids increases egg size and egg quality of H. kuda.

  12. Experimental Warming Decreases the Average Size and Nucleic Acid Content of Marine Bacterial Communities

    PubMed Central

    Huete-Stauffer, Tamara M.; Arandia-Gorostidi, Nestor; Alonso-Sáez, Laura; Morán, Xosé Anxelu G.

    2016-01-01

    Organism size reduction with increasing temperature has been suggested as a universal response to global warming. Since genome size is usually correlated to cell size, reduction of genome size in unicells could be a parallel outcome of warming at ecological and evolutionary time scales. In this study, the short-term response of cell size and nucleic acid content of coastal marine prokaryotic communities to temperature was studied over a full annual cycle at a NE Atlantic temperate site. We used flow cytometry and experimental warming incubations, spanning a 6°C range, to analyze the hypothesized reduction with temperature in the size of the widespread flow cytometric bacterial groups of high and low nucleic acid content (HNA and LNA bacteria, respectively). Our results showed decreases in size in response to experimental warming, which were more marked in 0.8 μm pre-filtered treatment rather than in the whole community treatment, thus excluding the role of protistan grazers in our findings. Interestingly, a significant effect of temperature on reducing the average nucleic acid content (NAC) of prokaryotic cells in the communities was also observed. Cell size and nucleic acid decrease with temperature were correlated, showing a common mean decrease of 0.4% per °C. The usually larger HNA bacteria consistently showed a greater reduction in cell and NAC compared with their LNA counterparts, especially during the spring phytoplankton bloom period associated to maximum bacterial growth rates in response to nutrient availability. Our results show that the already smallest planktonic microbes, yet with key roles in global biogeochemical cycling, are likely undergoing important structural shrinkage in response to rising temperatures. PMID:27242747

  13. Experimental Warming Decreases the Average Size and Nucleic Acid Content of Marine Bacterial Communities.

    PubMed

    Huete-Stauffer, Tamara M; Arandia-Gorostidi, Nestor; Alonso-Sáez, Laura; Morán, Xosé Anxelu G

    2016-01-01

    Organism size reduction with increasing temperature has been suggested as a universal response to global warming. Since genome size is usually correlated to cell size, reduction of genome size in unicells could be a parallel outcome of warming at ecological and evolutionary time scales. In this study, the short-term response of cell size and nucleic acid content of coastal marine prokaryotic communities to temperature was studied over a full annual cycle at a NE Atlantic temperate site. We used flow cytometry and experimental warming incubations, spanning a 6°C range, to analyze the hypothesized reduction with temperature in the size of the widespread flow cytometric bacterial groups of high and low nucleic acid content (HNA and LNA bacteria, respectively). Our results showed decreases in size in response to experimental warming, which were more marked in 0.8 μm pre-filtered treatment rather than in the whole community treatment, thus excluding the role of protistan grazers in our findings. Interestingly, a significant effect of temperature on reducing the average nucleic acid content (NAC) of prokaryotic cells in the communities was also observed. Cell size and nucleic acid decrease with temperature were correlated, showing a common mean decrease of 0.4% per °C. The usually larger HNA bacteria consistently showed a greater reduction in cell and NAC compared with their LNA counterparts, especially during the spring phytoplankton bloom period associated to maximum bacterial growth rates in response to nutrient availability. Our results show that the already smallest planktonic microbes, yet with key roles in global biogeochemical cycling, are likely undergoing important structural shrinkage in response to rising temperatures. PMID:27242747

  14. Experimental Warming Decreases the Average Size and Nucleic Acid Content of Marine Bacterial Communities.

    PubMed

    Huete-Stauffer, Tamara M; Arandia-Gorostidi, Nestor; Alonso-Sáez, Laura; Morán, Xosé Anxelu G

    2016-01-01

    Organism size reduction with increasing temperature has been suggested as a universal response to global warming. Since genome size is usually correlated to cell size, reduction of genome size in unicells could be a parallel outcome of warming at ecological and evolutionary time scales. In this study, the short-term response of cell size and nucleic acid content of coastal marine prokaryotic communities to temperature was studied over a full annual cycle at a NE Atlantic temperate site. We used flow cytometry and experimental warming incubations, spanning a 6°C range, to analyze the hypothesized reduction with temperature in the size of the widespread flow cytometric bacterial groups of high and low nucleic acid content (HNA and LNA bacteria, respectively). Our results showed decreases in size in response to experimental warming, which were more marked in 0.8 μm pre-filtered treatment rather than in the whole community treatment, thus excluding the role of protistan grazers in our findings. Interestingly, a significant effect of temperature on reducing the average nucleic acid content (NAC) of prokaryotic cells in the communities was also observed. Cell size and nucleic acid decrease with temperature were correlated, showing a common mean decrease of 0.4% per °C. The usually larger HNA bacteria consistently showed a greater reduction in cell and NAC compared with their LNA counterparts, especially during the spring phytoplankton bloom period associated to maximum bacterial growth rates in response to nutrient availability. Our results show that the already smallest planktonic microbes, yet with key roles in global biogeochemical cycling, are likely undergoing important structural shrinkage in response to rising temperatures.

  15. A direct method for evaluating the concentration of boric acid in a fuel pool using scintillation detectors for joint-multiplicity measurements

    NASA Astrophysics Data System (ADS)

    Chernikova, Dina; Axell, Kåre; Pázsit, Imre; Nordlund, Anders; Sarwar, Rashed

    2013-06-01

    The present investigations are aimed at the development of a direct passive non-intrusive method for determining the concentration of boric acid in a spent fuel pool using scintillation detectors with the purpose of correcting joint-multiplicity measurement results. The method utilizes a modified relation between two gamma lines with energy of 480 keV and 2.23 MeV, respectively. The gamma line at 480 keV belongs to the thermal neutron capture in boron. The 2.23 MeV gamma line characterizes the capture of thermal neutrons in hydrogen. Thus, the relation between them can reveal the concentration of the boron in the fuel pool. In order to test this method, first MCNPX and MCNP-PoliMi simulations were performed. Then, based on the results of Monte Carlo simulations, the method was verified by an experimental study with a 241Am-Be source and EJ-309 scintillation detectors. The concentration of boron in water varied from 1550 ppm to 4000 ppm. The results of these tests are provided in the paper and they show that the spectral ratio between these two lines can in principle be used to determine the boron content.

  16. Carbon concentrations and transformations in peatland pools

    NASA Astrophysics Data System (ADS)

    Chapman, Pippa; Holden, Joseph; Baird, Andrew; Turner, Edward; Dooling, Gemma; Billett, Mike; McKenzie, Rebecca; Leith, Fraser; Dinsmore, Kerry

    2016-04-01

    Peatland pools may act as important features for aquatic and gaseous carbon production, transformation and release. Peatland restoration often results in new pools being created. Here we compare aquatic carbon concentrations in nearby natural and artificial pool systems monitored at three sites in northern Scotland over a three-year period. We found significant differences in pool water carbon concentrations between pool types with larger dissolved organic carbon (DOC) and dissolved carbon dioxide (CO2) in artificial pools. The differences were strong for all sites and occurred in all seasons. Importantly, the DOC outflows from natural pools were markedly lower than the DOC flowing into natural pools showing that processes in these pools were transforming and removing the DOC. These effects were not found in the artificial pools. Data on the composition of the DOC (absorbance ratios, specific ultraviolet absorbance) suggested that natural pools tended to have DOC that had been processed, and was older (radiocarbon dating) while the DOC in artificial pools was young and had not undergone much biochemical processing. Slope position was an important factor influencing pool DOC with those pools with a longer upslope contributing area and collecting water with a longer hillslope residence time having larger DOC concentrations. Dissolved methane (CH4) concentrations were not significantly different between pool types but the concentrations were always above atmospheric levels with values ˜ 200 times atmospheric concentrations not uncommon. Dissolved CO2 concentrations in the artificial pools were extremely large; typically ˜20 times atmospheric levels while those in natural pools were typically only just above atmospheric levels. The pools were strong sources of CH4 and CO2 evasion from the peat system. The smaller size of the artificial pools means that more of their CO2 is stored in the water until it reaches the stream system, while the larger natural pools have

  17. Analysis of submicron-sized niflumic acid crystals prepared by electrospray crystallization.

    PubMed

    Ambrus, Rita; Radacsi, Norbert; Szunyogh, Tímea; van der Heijden, Antoine E D M; Ter Horst, Joop H; Szabó-Révész, Piroska

    2013-03-25

    Interest in submicron-sized drug particles has emerged from both laboratory and industrial perspectives in the last decade. Production of crystals in the nano size scale offers a novel way to particles for drug formulation solving formulation problems of drugs with low solubility in class II of the Biopharmaceutical Classification System. In this work niflumic acid nanoparticles with a size range of 200-800nm were produced by the novel crystallization method, electrospray crystallization. Their properties were compared to those from evaporative and anti-solvent crystallizations, using the same organic solvent, acetone. There is a remarkable difference in the product crystal size depending on the applied methods. The size and morphology were analyzed by scanning electron microscopy and laser diffraction. The structure of the samples was investigated using differential scanning calorimetry, Fourier-transformed infrared spectroscopy and X-ray powder diffraction. The particles produced using electrospray crystallization process were probably changing from amorphous to crystalline state after the procedure.

  18. Effect of eight outer continental shelf drilling muds on the calcification rate and free amino acid pool of the coral Acropora cervicornis

    SciTech Connect

    Powell, E.N.; Kendall, J.J. Jr.; Connor, S.J.; Zastrow, C.E.; Bright, T.J.

    1984-09-01

    During most offshore drilling operations, drilling muds are routinely discharged into surrounding waters. Because corals are relatively sensitive to many environmental perturbations and can be adversely affected by offshore drilling operations, the effects of drilling muds on corals have received considerable attention. Because drilling muds are discharged intermittently, only periodic exposures of short duration should impact nearby coral reefs. To fully assess the impact of a drilling mud discharge on corals requires an assessment of the capacity for corals to recover from short-term exposure. The purpose of this study was to assess the relative toxicity of a number of muds that were slated for marine disposal for the coral Acropora cervicornis after a 48-hr recovery period. Calcification rate and free amino acid pool were investigated.

  19. Fatty acid composition of an oral load affects chylomicron size in human subjects.

    PubMed

    Sakr, S W; Attia, N; Haourigui, M; Paul, J L; Soni, T; Vacher, D; Girard-Globa, A

    1997-01-01

    HDL-phospholipids are determinants in reverse cholesterol transport. They are mostly derived from triacylglycerol (TG)-rich lipoproteins. Chylomicron size is important, therefore, because it is related to the ratio surface phospholipids: core TG and, thus, determines the availability of postprandial phospholipids for transfer to HDL. Eleven healthy young women each ingested four different fat loads supplemented with retinyl palmitate and containing 60 g sunflower oil (SO), oleic-sunflower oil (OSO), mixed oil (MO; (g/kg) linoleic acid 480, oleic acid 380, linolenic acid 13) or beef tallow (BT). At the peak of TG absorption for all loads (4 h) chylomicron diameters, determined by agarose-gel filtration, were larger after SO compared with OSO (P < 0.05) and BT (P = 0.06) and after MO compared with BT (P < 0.05). At 6 h chylomicron size was larger after the vegetable oils compared with BT (P < 0.05 in each case). After each fat load chylomicron size decreased at 6 and 8 h compared with that at 4 h (P < 0.05) except for OSO. Retinyl ester and TG concentrations were lower in chylomicrons after BT than after the other fats but not in the chylomicron-free serum (containing chylomicron remnants), suggesting absorption in the form of very small particles. Compared with the fasting value, the concentration of the Svedberg unit of flotation 20-400 fraction, which contains VLDL and chylomicron remnants, was lower 8 h after MO, the only fat to contain significant amounts of linolenic acid. We conclude that chylomicron size is dependent on the fatty acid composition of ingested fats and the time-course of digestion, being larger for polyunsaturated fatty acid-rich fats and in the early phase of digestion. On the basis of retinyl ester concentration there were no differences between fats in chylomicron-remnant clearance.

  20. 77 FR 68133 - Guidance for Industry: Use of Nucleic Acid Tests on Pooled and Individual Samples From Donors of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-15

    ... November 28, 2011 (76 FR 72950), FDA announced the availability of the draft guidance of the same title...) deoxyribonucleic acid (DNA) and recommendations for product testing and disposition, donor management, methods for... screen blood donors for HBV DNA. FDA is also providing these blood establishments with...

  1. Low Temperature Effects on Soybean (Glycine max [L.] Merr. cv. Wells) Free Amino Acid Pools during Germination 1

    PubMed Central

    Duke, Stanley H.; Schrader, Larry E.; Miller, Marna Geyer; Niece, Ronald L.

    1978-01-01

    The free amino acid concentrations in cotyledons and axes of soybean (Glycine max [L.] Merr. cv. Wells) seedlings were determined by automated single column analysis after germination at 10 and 23 C. After 5 days germination at 10 C, glutamate and aspartate were in high concentration in both cotyledons and axes (38 and 24% of total free amino acids recovered, respectively), whereas the concentrations of their amide derivatives, asparagine and glutamine, were low in cotyledons (4.4%) and high in axes (21%). In contrast, after 5 days germination at 23 C, asparagine and glutamine accounted for 22 and 45% of total free amino acids in cotyledons and axes respectively, and aspartate and glutamate concentrations were low. The activities of glutamine synthetase and asparagine synthetase were considerably lower in tissues from the 10 C treatment than those from the 23 C treatment. Aspartate and glutamate concentrations were nearly equal in all but one sample. Both glutamate oxaloacetate transaminase and glutamate dehydrogenase activities were much higher in axis tissues at 23 C as compared to 10 C. Arrhenius plots of axis glutamate oxaloacetate transaminase and glutamate dehydrogenase activities were biphasic and triphasic, respectively, with energies of activation for both increasing with low temperature. Energies of activation were identical for glutamate oxaloacetate transaminase from 10 and 23 C treatments but much higher for glutamate dehydrogenase from 23 C-treated axes. This indicates a difference in enzyme complement for glutamate dehydrogenase with the two treatments. Hydrolysis of free amino acid sample (basic fraction) aliquots showed large quantities of peptides in 23 C-treated axes at 2 days, while few or no peptides were found in the 10 C treatment. Amino acid residues most prevalent in peptides were aspartate, threonine, serine, glutamate, and glycine. PMID:16660575

  2. Swimming pools soak up the sun

    SciTech Connect

    Cuoghi, D.; Hesse, P.; Schiller, T.

    1996-05-01

    Solar pool heaters survived the boom and bust solar years of the 1970s and 1980s. Today they are even popular and cost-effective in parts of the country where many people think solar is impractical. This article discusses the following topics: how solar pool heaters work; types of solar pool heater collectors; collector and pump sizing; collector siting and mounting; systems costs and economics; pool covers. 3 figs.

  3. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

    PubMed

    Garzke, Jessica; Hansen, Thomas; Ismar, Stefanie M H; Sommer, Ulrich

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts. PMID:27224476

  4. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

    PubMed

    Garzke, Jessica; Hansen, Thomas; Ismar, Stefanie M H; Sommer, Ulrich

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts.

  5. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content

    PubMed Central

    Hansen, Thomas; Ismar, Stefanie M. H.; Sommer, Ulrich

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1–5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts. PMID:27224476

  6. Size Distribution Studies on Sulfuric Acid-Water Particles in a Photolytic Reactor

    NASA Astrophysics Data System (ADS)

    Abdullahi, H. U.; Kunz, J. C.; Hanson, D. R.; Thao, S.; Vences, J.

    2015-12-01

    The size distribution of particles composed of sulfuric acid and water were measured in a Photolytic cylindrical Flow Reactor (PhoFR, inner diameter 5 cm, length ~ 100 cm). In the reactor, nitrous acid, water and sulfur dioxide gases along with ultraviolet light produced sulfuric acid. The particles formed from these vapors were detected with a scanning mobility particle spectrometer equipped with a diethylene glycol condensation particle counter (Jiang et al. 2011). For a set of standard conditions, particles attained a log-normal distribution with a peak diameter of 6 nm, and a total number of about 3x105 cm-3. The distributions show that ~70 % of the particles are between 4 and 8 nm diameter (lnσ ~ 0.37). These standard conditions are: 296 K, 25% relative humidity, total flow = 3 sLpm, ~10 ppbv HONO, SO2 in excess. With variations of relative humidity, the total particle number varied strongly, with a power relationship of ~3.5, and the size distributions showed a slight increase in peak diameter with relative humidity, increasing about 1 nm from 8 to 33 % relative humidity. Variations of HONO at a constant light intensity (wavelength of ~ 360 nm) were performed and particle size and total number changed dramatically. Size distributions also changed drastically with variations of light intensity, accomplished by turning on/off some of the black light flourescent bulbs that illuminated the flow reactor. Comparisons of these size distributions to recently published nucleation experiments (e.g. Zollner et al., Glasoe et al.) as well as to simulations of PhoFR reveal important details about the levels of sulfuric acid present in PhoFR as well as possible base contaminants.

  7. Amino acid substitution at the Adh locus of Drosophila is facilitated by small population size.

    PubMed Central

    Ohta, T

    1993-01-01

    The number of amino acid replacement substitutions and that of synonymous substitutions are examined by using DNA sequences of the Adh locus of Drosophila. The ratio of replacement to synonymous substitutions is higher in sequence comparisons between species than in polymorphisms within species. The ratio for the between-species comparisons is highest in the Hawaiian group and lowest in the obscura group. These observations suggest that amino acid substitutions are facilitated by small population size. The result is in accord with the nearly neutral theory of molecular evolution. PMID:8506297

  8. Caprylic acid-induced impurity precipitation from protein A capture column elution pool to enable a two-chromatography-step process for monoclonal antibody purification.

    PubMed

    Zheng, Ji; Wang, Lu; Twarowska, Barbara; Laino, Sarah; Sparks, Colleen; Smith, Timothy; Russell, Reb; Wang, Michelle

    2015-01-01

    This article presents the use of caprylic acid (CA) to precipitate impurities from the protein A capture column elution pool for the purification of monoclonal antibodies (mAbs) with the objective of developing a two chromatography step antibody purification process. A CA-induced impurity precipitation in the protein A column elution pool was evaluated as an alternative method to polishing chromatography techniques for use in the purification of mAbs. Parameters including pH, CA concentrations, mixing time, mAb concentrations, buffer systems, and incubation temperatures were evaluated on their impacts on the impurity removal, high-molecular weight (HMW) formation and precipitation step yield. Both pH and CA concentration, but not mAb concentrations and buffer systems, are key parameters that can affect host-cell proteins (HCPs) clearance, HMW species, and yield. CA precipitation removes HCPs and some HMW species to the acceptable levels under the optimal conditions. The CA precipitation process is robust at 15-25°C. For all five mAbs tested in this study, the optimal CA concentration range is 0.5-1.0%, while the pH range is from 5.0 to 6.0. A purification process using two chromatography steps (protein A capture column and ion exchange polishing column) in combination with CA-based impurity precipitation step can be used as a robust downstream process for mAb molecules with a broad range of isoelectric points. Residual CA can be effectively removed by the subsequent polishing cation exchange chromatography.

  9. Does Cation Size Affect Occupancy and Electrostatic Screening of the Nucleic Acid Ion Atmosphere?

    PubMed

    Gebala, Magdalena; Bonilla, Steve; Bisaria, Namita; Herschlag, Daniel

    2016-08-31

    Electrostatics are central to all aspects of nucleic acid behavior, including their folding, condensation, and binding to other molecules, and the energetics of these processes are profoundly influenced by the ion atmosphere that surrounds nucleic acids. Given the highly complex and dynamic nature of the ion atmosphere, understanding its properties and effects will require synergy between computational modeling and experiment. Prior computational models and experiments suggest that cation occupancy in the ion atmosphere depends on the size of the cation. However, the computational models have not been independently tested, and the experimentally observed effects were small. Here, we evaluate a computational model of ion size effects by experimentally testing a blind prediction made from that model, and we present additional experimental results that extend our understanding of the ion atmosphere. Giambasu et al. developed and implemented a three-dimensional reference interaction site (3D-RISM) model for monovalent cations surrounding DNA and RNA helices, and this model predicts that Na(+) would outcompete Cs(+) by 1.8-2.1-fold; i.e., with Cs(+) in 2-fold excess of Na(+) the ion atmosphere would contain an equal number of each cation (Nucleic Acids Res. 2015, 43, 8405). However, our ion counting experiments indicate that there is no significant preference for Na(+) over Cs(+). There is an ∼25% preferential occupancy of Li(+) over larger cations in the ion atmosphere but, counter to general expectations from existing models, no size dependence for the other alkali metal ions. Further, we followed the folding of the P4-P6 RNA and showed that differences in folding with different alkali metal ions observed at high concentration arise from cation-anion interactions and not cation size effects. Overall, our results provide a critical test of a computational prediction, fundamental information about ion atmosphere properties, and parameters that will aid in the

  10. Particle size tailoring of ursolic acid nanosuspensions for improved anticancer activity by controlled antisolvent precipitation.

    PubMed

    Wang, Yancai; Song, Ju; Chow, Shing Fung; Chow, Albert H L; Zheng, Ying

    2015-10-15

    The present study was aimed at tailoring the particle size of ursolic acid (UA) nanosuspension for improved anticancer activity. UA nanosuspensions were prepared by antisolvent precipitation using a four-stream multi-inlet vortex mixer (MIVM) under defined conditions of varying solvent composition, drug feeding concentration or stream flow rate. The resulting products were characterized for particle size and polydispersity. Two of the UA nanosuspensions with mean particle sizes of 100 and 300 nm were further assessed for their in-vitro activity against MCF-7 breast cancer cells using fluorescence microscopy with 4',6-diamidino-2-phenylindole (DAPI) staining, as well as flow cytometry with propidium (PI) staining and with double staining by fluorescein isothiocyanate. It was revealed that the solvent composition, drug feeding concentration and stream flow rate were critical parameters for particle size control of the UA nanosuspensions generated with the MIVM. Specifically, decreasing the UA feeding concentration or increasing the stream flow rate or ethanol content resulted in a reduction of particle size. Excellent reproducibility for nanosuspension production was demonstrated for the 100 and 300 nm UA preparations with a deviation of not more than 5% in particle size from the mean value of three independent batches. Fluorescence microscopy and flow cytometry revealed that these two different sized UA nanosuspensions, particularly the 300 nm sample, exhibited a higher anti-proliferation activity against the MCF-7 cells and afforded a larger population of these cells in both early and late apoptotic phases. In conclusion, MIVM is a robust and pragmatic tool for tailoring the particle size of the UA nanosuspension. Particle size appears to be a critical determinant of the anticancer activity of the UA nanoparticles.

  11. Particle size tailoring of ursolic acid nanosuspensions for improved anticancer activity by controlled antisolvent precipitation.

    PubMed

    Wang, Yancai; Song, Ju; Chow, Shing Fung; Chow, Albert H L; Zheng, Ying

    2015-10-15

    The present study was aimed at tailoring the particle size of ursolic acid (UA) nanosuspension for improved anticancer activity. UA nanosuspensions were prepared by antisolvent precipitation using a four-stream multi-inlet vortex mixer (MIVM) under defined conditions of varying solvent composition, drug feeding concentration or stream flow rate. The resulting products were characterized for particle size and polydispersity. Two of the UA nanosuspensions with mean particle sizes of 100 and 300 nm were further assessed for their in-vitro activity against MCF-7 breast cancer cells using fluorescence microscopy with 4',6-diamidino-2-phenylindole (DAPI) staining, as well as flow cytometry with propidium (PI) staining and with double staining by fluorescein isothiocyanate. It was revealed that the solvent composition, drug feeding concentration and stream flow rate were critical parameters for particle size control of the UA nanosuspensions generated with the MIVM. Specifically, decreasing the UA feeding concentration or increasing the stream flow rate or ethanol content resulted in a reduction of particle size. Excellent reproducibility for nanosuspension production was demonstrated for the 100 and 300 nm UA preparations with a deviation of not more than 5% in particle size from the mean value of three independent batches. Fluorescence microscopy and flow cytometry revealed that these two different sized UA nanosuspensions, particularly the 300 nm sample, exhibited a higher anti-proliferation activity against the MCF-7 cells and afforded a larger population of these cells in both early and late apoptotic phases. In conclusion, MIVM is a robust and pragmatic tool for tailoring the particle size of the UA nanosuspension. Particle size appears to be a critical determinant of the anticancer activity of the UA nanoparticles. PMID:26302857

  12. A simple route for renewable nano-sized arjunolic and asiatic acids and self-assembly of arjuna-bromolactone.

    PubMed

    Bag, Braja G; Dey, Partha P; Dinda, Shaishab K; Sheldrick, William S; Oppel, Iris M

    2008-01-01

    While separating two natural nano-sized triterpenic acids via bromolactonization, we serendipitously discovered that arjuna-bromolactone is an excellent gelator of various organic solvents. A simple and efficient method for the separation of two triterpenic acids and the gelation ability and solid state 1D-helical self-assembly of nano-sized arjuna-bromolactone are reported.

  13. Chemical composition and bioactivity properties of size-fractions separated from a vermicompost humic acid.

    PubMed

    Canellas, Luciano P; Piccolo, Alessandro; Dobbss, Leonardo B; Spaccini, Riccardo; Olivares, Fábio L; Zandonadi, Daniel B; Façanha, Arnoldo R

    2010-01-01

    Preparative high performance size-exclusion chromatography (HPSEC) was applied to humic acids (HA) extracted from vermicompost in order to separate humic matter of different molecular dimension and evaluate the relationship between chemical properties of size-fractions (SF) and their effects on plant root growth. Molecular dimensions of components in humic SF was further achieved by diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY-NMR) based on diffusion coefficients (D), while carbon distribution was evaluated by solid state (CP/MAS) (13)C NMR. Seedlings of maize and Arabidopsis were treated with different concentrations of SF to evaluate root growth. Six different SF were obtained and their carbohydrate-like content and alkyl chain length decreased with decreasing molecular size. Progressive reduction of aromatic carbon was also observed with decreasing molecular size of separated fractions. Diffusion-ordered spectroscopy (DOSY) spectra showed that SF were composed of complex mixtures of aliphatic, aromatic and carbohydrates constituents that could be separated on the basis of their diffusion. All SF promoted root growth in Arabidopsis and maize seedlings but the effects differed according to molecular size and plant species. In Arabidopsis seedlings, the bulk HA and its SF revealed a classical large auxin-like exogenous response, i.e.: shortened the principal root axis and induced lateral roots, while the effects in maize corresponded to low auxin-like levels, as suggested by enhanced principal axis length and induction of lateral roots. The reduction of humic heterogeneity obtained in HPSEC separated size-fractions suggested that their physiological influence on root growth and architecture was less an effect of their size than their content of specific bioactive molecules. However, these molecules may be dynamically released from humic superstructures and exert their bioactivity when weaker is the humic conformational stability as that obtained

  14. Hydrogen isotopes in individual amino acids reflect differentiated pools of hydrogen from food and water in Escherichia coli.

    PubMed

    Fogel, Marilyn L; Griffin, Patrick L; Newsome, Seth D

    2016-08-01

    Hydrogen isotope (δ(2)H) analysis is widely used in animal ecology to study continental-scale movement because δ(2)H can trace precipitation and climate. To understand the biochemical underpinnings of how hydrogen is incorporated into biomolecules, we measured the δ(2)H of individual amino acids (AAs) in Escherichia coli cultured in glucose-based or complex tryptone-based media in waters with δ(2)H values ranging from -55‰ to +1,070‰. The δ(2)H values of AAs in tryptone spanned a range of ∼250‰. In E. coli grown on glucose, the range of δ(2)H among AAs was nearly 200‰. The relative distributions of δ(2)H of AAs were upheld in cultures grown in enriched waters. In E. coli grown on tryptone, the δ(2)H of nonessential AAs varied linearly with the δ(2)H of media water, whereas δ(2)H of essential AAs was nearly identical to δ(2)H in diet. Model calculations determined that as much as 46% of hydrogen in some nonessential AAs originated from water, whereas no more than 12% of hydrogen in essential AAs originated from water. These findings demonstrate that δ(2)H can route directly at the molecular level. We conclude that the patterns and distributions in δ(2)H of AAs are determined through biosynthetic reactions, suggesting that δ(2)H could become a new biosignature for studying novel microbial pathways. Our results also show that δ(2)H of AAs in an organism's tissues provides a dual tracer for food and environmental (e.g., drinking) water. PMID:27444017

  15. Hydrogen isotopes in individual amino acids reflect differentiated pools of hydrogen from food and water in Escherichia coli.

    PubMed

    Fogel, Marilyn L; Griffin, Patrick L; Newsome, Seth D

    2016-08-01

    Hydrogen isotope (δ(2)H) analysis is widely used in animal ecology to study continental-scale movement because δ(2)H can trace precipitation and climate. To understand the biochemical underpinnings of how hydrogen is incorporated into biomolecules, we measured the δ(2)H of individual amino acids (AAs) in Escherichia coli cultured in glucose-based or complex tryptone-based media in waters with δ(2)H values ranging from -55‰ to +1,070‰. The δ(2)H values of AAs in tryptone spanned a range of ∼250‰. In E. coli grown on glucose, the range of δ(2)H among AAs was nearly 200‰. The relative distributions of δ(2)H of AAs were upheld in cultures grown in enriched waters. In E. coli grown on tryptone, the δ(2)H of nonessential AAs varied linearly with the δ(2)H of media water, whereas δ(2)H of essential AAs was nearly identical to δ(2)H in diet. Model calculations determined that as much as 46% of hydrogen in some nonessential AAs originated from water, whereas no more than 12% of hydrogen in essential AAs originated from water. These findings demonstrate that δ(2)H can route directly at the molecular level. We conclude that the patterns and distributions in δ(2)H of AAs are determined through biosynthetic reactions, suggesting that δ(2)H could become a new biosignature for studying novel microbial pathways. Our results also show that δ(2)H of AAs in an organism's tissues provides a dual tracer for food and environmental (e.g., drinking) water.

  16. A Genetic Cascade of let-7-ncl-1-fib-1 Modulates Nucleolar Size and rRNA Pool in Caenorhabditis elegans

    PubMed Central

    Chiou, Pey-Tsyr; Chen, Po-Hsiang; Lee, Ching-Ming; Chu, Yu-De; Yu, Hsiang; Hsiung, Kuei-Ching; Tsai, Yi-Tzang; Lee, Chi-Chang; Chang, Yu-Sun; Chan, Shih-Peng; Tan, Bertrand Chin-Ming; Lo, Szecheng J.

    2015-01-01

    Ribosome biogenesis takes place in the nucleolus, the size of which is often coordinated with cell growth and development. However, how metazoans control nucleolar size remains largely unknown. Caenorhabditis elegans provides a good model to address this question owing to distinct tissue distribution of nucleolar sizes and a mutant, ncl-1, which exhibits larger nucleoli than wild-type worms. Here, through a series of loss-of-function analyses, we report that the nucleolar size is regulated by a circuitry composed of microRNA let-7, translation repressor NCL-1, and a major nucleolar pre-rRNA processing protein FIB-1/fibrillarin. In cooperation with RNA binding proteins PUF and NOS, NCL-1 suppressed the translation of FIB-1/fibrillarin, while let-7 targeted the 3’UTR of ncl-1 and inhibited its expression. Consequently, the abundance of FIB-1 is tightly controlled and correlated with the nucleolar size. Together, our findings highlight a novel genetic cascade by which post-transcriptional regulators interplay in developmental control of nucleolar size and function. PMID:26492166

  17. Control of Alginate Core Size in Alginate-Poly (Lactic-Co-Glycolic) Acid Microparticles

    NASA Astrophysics Data System (ADS)

    Lio, Daniel; Yeo, David; Xu, Chenjie

    2016-01-01

    Core-shell alginate-poly (lactic-co-glycolic) acid (PLGA) microparticles are potential candidates to improve hydrophilic drug loading while facilitating controlled release. This report studies the influence of the alginate core size on the drug release profile of alginate-PLGA microparticles and its size. Microparticles are synthesized through double-emulsion fabrication via a concurrent ionotropic gelation and solvent extraction. The size of alginate core ranges from approximately 10, 50, to 100 μm when the emulsification method at the first step is homogenization, vortexing, or magnetic stirring, respectively. The second step emulsification for all three conditions is performed with magnetic stirring. Interestingly, although the alginate core has different sizes, alginate-PLGA microparticle diameter does not change. However, drug release profiles are dramatically different for microparticles comprising different-sized alginate cores. Specifically, taking calcein as a model drug, microparticles containing the smallest alginate core (10 μm) show the slowest release over a period of 26 days with burst release less than 1 %.

  18. Swimming Pool Safety

    MedlinePlus

    ... insist that the following rules are followed: Keep toys away from the pool when the pool is ... after each use. No tricycles or other riding toys at poolside. No electrical appliances near the pool. ...

  19. THE OUTDOOR POOL

    PubMed Central

    Craster, Charles V.

    1919-01-01

    That almost any bit of water will serve for a wading pool seems to be the idea in practice. Dr. Craster has tested such pools and finds that they need to be as well constructed as bathing pools and as well cared for. Chlorination is necessary when they can not otherwise be controlled. ImagesPOOL I.POOL II.POOL III.p826-a PMID:18010192

  20. Submicrometer-sized Pickering emulsions stabilized by silica nanoparticles with adsorbed oleic acid.

    PubMed

    Sadeghpour, Amin; Pirolt, Franz; Glatter, Otto

    2013-05-21

    Oil-water Pickering emulsions of about 200 nm were stabilized by nanosized hydrophilic silica after a simple surface treatment method. We have modified the aqueous silica nanoparticle dispersions by simple adsorption of oleic acid to their surfaces, improving the hydrophobicity of the particles while maintaining their charge and stability. The adsorption was monitored by small-angle X-ray scattering and electrophoretic measurements to estimate the interparticle interactions and surface charges. The effect of various parameters, such as nanoparticle concentration, amount of oleic acid, ionic strength, and pH, on the droplets' size and stability was investigated by dynamic light scattering. Furthermore, the ability of these modified silica nanoparticles to stabilize long-chain alkanes, liquid paraffin, and liquid-crystalline phases was examined.

  1. Effect of hydrofluoric acid (HF) concentration to pores size diameter of silicon membrane.

    PubMed

    Burham, Norhafizah; Hamzah, Azrul Azlan; Majlis, Burhanuddin Yeop

    2014-01-01

    This paper studies parameters which affect the pore size diameter of a silicon membrane. Electrochemical etching is performed in characterise the parameter involved in this process. The parameter has been studied is volume ratio of hydrofluoric acid (HF) and ethanol as an electrolyte aqueous for electrochemical etch. This electrolyte aqueous solution has been mixed between HF and ethanol with volume ratio 3:7, 5:5, 7:3 and 9:1. As a result, the higher volume of HF in this electrolyte gives the smallest pore size diameter compared to the lower volume of HF. These samples have been dipped into HF and ethanol electrolyte aqueous with supplied 25 mA/cm2 current density for 20, 30, 40, and 50 minutes. The samples will inspect under Scanning Electron Microscope (SEM) to execute the pore formations on silicon membrane surface.

  2. Strength training increases the size of the satellite cell pool in type I and II fibres of chronically painful trapezius muscle in females

    PubMed Central

    Mackey, Abigail L; Andersen, Lars L; Frandsen, Ulrik; Sjøgaard, Gisela

    2011-01-01

    Abstract While strength training has been shown to be effective in mediating hypertrophy and reducing pain in trapezius myalgia, responses at the cellular level have not previously been studied. This study investigated the potential of strength training targeting the affected muscles (SST, n = 18) and general fitness training (GFT, n = 16) to augment the satellite cell (SC) and macrophage pools in the trapezius muscles of women diagnosed with trapezius myalgia. A group receiving general health information (REF, n = 8) served as a control. Muscle biopsies were collected from the trapezius muscles of the 42 women (age 44 ± 8 years; mean ± SD) before and after the 10 week intervention period and were analysed by immunohistochemistry for SCs, macrophages and myonuclei. The SC content of type I and II fibres was observed to increase significantly from baseline by 65% and 164%, respectively, with SST (P < 0.0001), together with a significant correlation between the baseline number of SCs and the extent of hypertrophy (r = −0.669, P = 0.005). SST also resulted in a 74% enhancement of the trapezius macrophage content (P < 0.01), accompanied by evidence for the presence of an increased number of actively dividing cells (Ki67+) post-SST (P < 0.001). GFT resulted in a significant 23% increase in the SC content of type II fibres, when expressed relative to myonuclear number only (P < 0.05). No changes in the number of myonuclei per fibre or myonuclear domain were detected in any group. These findings provide strong support at the cellular level for the potential of SST to induce a strong myogenic response in this population. PMID:21946848

  3. Demographic consequences of terrestrial habitat loss for pool-breeding amphibians: predicting extinction risks associated with inadequate size of buffer zones.

    PubMed

    Harper, Elizabeth B; Rittenhouse, Tracy A G; Semlitsch, Raymond D

    2008-10-01

    Much of the biodiversity associated with isolated wetlands requires aquatic and terrestrial habitat to maintain viable populations. Current federal wetland regulations in the United States do not protect isolated wetlands or extend protection to surrounding terrestrial habitat. Consequently, some land managers, city planners, and policy makers at the state and local levels are making an effort to protect these wetland and neighboring upland habitats. Balancing human land-use and habitat conservation is challenging, and well-informed land-use policy is hindered by a lack of knowledge of the specific risks of varying amounts of habitat loss. Using projections of wood frog (Rana sylvatica) and spotted salamander (Ambystoma maculatum) populations, we related the amount of high-quality terrestrial habitat surrounding isolated wetlands to the decline and risk of extinction of local amphibian populations. These simulations showed that current state-level wetland regulations protecting 30 m or less of surrounding terrestrial habitat are inadequate to support viable populations of pool-breeding amphibians. We also found that species with different life-history strategies responded differently to the loss and degradation of terrestrial habitat. The wood frog, with a short life span and high fecundity, was most sensitive to habitat loss and isolation, whereas the longer-lived spotted salamander with lower fecundity was most sensitive to habitat degradation that lowered adult survival rates. Our model results demonstrate that a high probability of local amphibian population persistence requires sufficient terrestrial habitat, the maintenance of habitat quality, and connectivity among local populations. Our results emphasize the essential role of adequate terrestrial habitat to the maintenance of wetland biodiversity and ecosystem function and offer a means of quantifying the risks associated with terrestrial habitat loss and degradation.

  4. Collaborative study for establishment of a European Pharmacopoei Biological Reference Preparation (BRP) for B19 virus DNA testing of plasma pools by nucleic acid amplification technique.

    PubMed

    Nübling, C M; Daas, A; Buchheit, K H

    2004-01-01

    The goal of the collaborative study was to calibrate the B19 DNA content of a candidate Biological Reference Preparation (BRP) that is intended to be used for the validation of the analytical procedure, as threshold control and/or as quantitative reference material in the Nucleic Acid Amplification Technique (NAT) test of plasma pools for detection of B19 contamination. The candidate BRP was calibrated against the 1st International Standard for B19 DNA NAT assays. According to the European Pharmacopoeia monograph Human anti-D immunoglobulin, the threshold control needs to have a titre of 10( 4) IU/ml of B19 virus DNA. The lyophilised candidate BRP was prepared from 0.5 ml aliquots of a plasma pool spiked with B19 virus. The B19 virus originated from a "B19 virus window phase" blood donation (anti-B19 negative, B19-DNA high titre positive) and was diluted in a plasma pool tested negative by both serological and NAT assays for Hepatitis B Virus, Hepatitis C Virus and Human Immunodeficiency Virus 1 to obtain a B19-DNA concentration level in the range of 10( 6) copies/ml. The residual water content of the lyophilised candidate BRP was determined as 0.98 +/- 0.65% (mean +/- relative standard deviation). Sixteen laboratories (Official Medicine Control Laboratories, manufacturers of plasma derivatives, NAT test laboratories and NAT kit manufacturers) from nine countries participated. Participants were requested to test the candidate BRP and the International Standard (99/800) in four independent test runs on different days using their in-house qualitative and/or quantitative NAT methods. Sixteen laboratories reported results. Thirteen laboratories reported results from qualitative assays and 5 laboratories reported results from quantitative assays. Two laboratories reported results from both types of assay. For the qualitative assays a weighted combined potency of 5.64 log( 10) IU/ml with 95 per cent confidence limits of +/- 0.17 log( 10) which corresponds to 67 to 150

  5. Collaborative study for establishment of a European Pharmacopoei Biological Reference Preparation (BRP) for B19 virus DNA testing of plasma pools by nucleic acid amplification technique.

    PubMed

    Nübling, C M; Daas, A; Buchheit, K H

    2004-01-01

    The goal of the collaborative study was to calibrate the B19 DNA content of a candidate Biological Reference Preparation (BRP) that is intended to be used for the validation of the analytical procedure, as threshold control and/or as quantitative reference material in the Nucleic Acid Amplification Technique (NAT) test of plasma pools for detection of B19 contamination. The candidate BRP was calibrated against the 1st International Standard for B19 DNA NAT assays. According to the European Pharmacopoeia monograph Human anti-D immunoglobulin, the threshold control needs to have a titre of 10( 4) IU/ml of B19 virus DNA. The lyophilised candidate BRP was prepared from 0.5 ml aliquots of a plasma pool spiked with B19 virus. The B19 virus originated from a "B19 virus window phase" blood donation (anti-B19 negative, B19-DNA high titre positive) and was diluted in a plasma pool tested negative by both serological and NAT assays for Hepatitis B Virus, Hepatitis C Virus and Human Immunodeficiency Virus 1 to obtain a B19-DNA concentration level in the range of 10( 6) copies/ml. The residual water content of the lyophilised candidate BRP was determined as 0.98 +/- 0.65% (mean +/- relative standard deviation). Sixteen laboratories (Official Medicine Control Laboratories, manufacturers of plasma derivatives, NAT test laboratories and NAT kit manufacturers) from nine countries participated. Participants were requested to test the candidate BRP and the International Standard (99/800) in four independent test runs on different days using their in-house qualitative and/or quantitative NAT methods. Sixteen laboratories reported results. Thirteen laboratories reported results from qualitative assays and 5 laboratories reported results from quantitative assays. Two laboratories reported results from both types of assay. For the qualitative assays a weighted combined potency of 5.64 log( 10) IU/ml with 95 per cent confidence limits of +/- 0.17 log( 10) which corresponds to 67 to 150

  6. Contribution of ants in modifying of soil acidity and particle size distribution

    NASA Astrophysics Data System (ADS)

    Morgun, Alexandra; Golichenkov, Maxim

    2015-04-01

    Being a natural body, formed by the influence of biota on the upper layers of the Earth's crust, the soil is the most striking example of biogenic-abiogenic interactions in the biosphere. Invertebrates (especially ants that build soil nests) are important agents that change soil properties in well developed terrestrial ecosystems. Impact of soil microorganisms on soil properties is particularly described in numerous literature and concerns mainly chemical properties and general indicators of soil biological activity. Influence of ants (as representatives of the soil mesofauna) mostly appears as mechanical movement of soil particles and aggregates, and chemical effects caused by concentration of organic matter within the ant's nest. The aim of this research was to evaluate the effect of ants on physical and chemical soil attributes such as particle size distribution and soil acidity. The samples were taken from aerial parts of Lasius niger nests, selected on different elements of the relief (summit position, slope, terrace and floodplain) in the Arkhangelsk region (north of the European part of Russia) and compared with the specimens of the upper horizons of the reference soils. Particle size distribution was determined by laser diffraction method using laser diffraction particle size analyzer «Analysette 22 comfort» (FRITSCH, Germany). The acidity (pH) was determined by potentiometry in water suspension. Particle size distribution of the samples from the nests is more variable as compared to the control samples. For example, the content of 5-10 μm fraction ranges from 9% to 12% in reference soils, while in the anthill samples the variation is from 8% to 15%. Similarly, for 50-250 μm fraction - it ranges from 15% to 18% in reference soils, whereas in anthills - from 6% to 29%. The results of particle size analysis showed that the reference sample on the terrace has silty loam texture and nests soil L. niger are medium loam. The reference soil on the slope is

  7. Free and combined amino acids in size-segregated atmospheric aerosol samples

    NASA Astrophysics Data System (ADS)

    Di Filippo, Patrizia; Pomata, Donatella; Riccardi, Carmela; Buiarelli, Francesca; Gallo, Valentina; Quaranta, Alessandro

    2014-12-01

    Concentrations of free and combined amino acids in an urban atmosphere and their distributions in size-segregated particles were investigated in the cold and warm seasons. In particular this article provides the first investigation of protein bioaerosol concentrations in ultrafine fraction (PM0.1) of particulate matter. In addition the present work provides amino acid and total proteinaceous material concentrations in NIST SRM 1649b, useful as reference values. The reference material was also used to build matrix matched calibration curves. Free amino acid total content in winter and summer PM0.1 was respectively 48.0 and 94.4 ng m-3, representing about 0.7 and 7.4% by weight of urban particulate matter in the two seasons. Total airborne protein and peptide concentrations in the same ultrafine fractions were 93.6 and 449.9 ng m-3 respectively in winter and in summer, representing 7.5 and 35.4% w/w of PM0.1, and demonstrating an exceptionally high percentage in summer ultrafine fraction. The significant potential adverse health effects of ultrafine particulate matter include allergies mainly caused by protein particles and we assumed that in summer 162 ng h-1 of proteinaceous material, by means of ultrafine particles, can penetrate from the lungs into the bloodstream.

  8. Daily consumption of orange-fleshed sweet potato for 60 days increased plasma β-carotene concentration but did not increase total body vitamin A pool size in Bangladeshi women.

    PubMed

    Jamil, Kazi M; Brown, Kenneth H; Jamil, Maleka; Peerson, Janet M; Keenan, Alison H; Newman, John W; Haskell, Marjorie J

    2012-10-01

    We assessed the effect of daily consumption of orange-fleshed sweet potatoes (OFSP), with or without added fat, on the vitamin A (VA) status of Bangladeshi women with low initial VA status. Women (n = 30/group) received one of the following for 6 d/wk over 10 wk: 1) 0 μg retinol activity equivalents (RAE)/d as boiled white-fleshed sweet potatoes (WFSP) and a corn oil capsule, 2) 600 μg RAE/d as boiled OFSP and a corn oil capsule, 3) fried OFSP and a corn oil capsule, or 4) boiled WFSP and a retinyl palmitate capsule in addition to their home diets. Plasma concentrations of retinol and β-carotene and total body VA pool size were assessed before and after the 60-d intervention. Initial and final plasma retinol concentrations (mean ± SD) were 0.75 ± 0.18 μmol/L and 0.84 ± 0.19 μmol/L, respectively (P = 0.31); final means did not differ by group. Initial and final plasma β-carotene concentrations were 0.10 ± 00 μmol/L and 0.18 ± 0.09 μmol/L, respectively (P < 0.0001); final mean plasma β-carotene concentrations were higher in groups that received OFSP (P < 0.0001), and final mean plasma β-carotene was marginally higher in the group that received fried OFSP compared with boiled OFSP (P = 0.07). Initial and final total body VA pool sizes were 0.060 ± 0.047 mmol and 0.091 ± 0.070 mmol, respectively (P = 0.05, n = 110) and did not differ by group. Despite an increase in plasma β-carotene concentration, the impact of OFSP on VA status appears to be limited in Bangladeshi women residing in a resource-poor community.

  9. Daily consumption of orange-fleshed sweet potato for 60 days increased plasma β-carotene concentration but did not increase total body vitamin A pool size in Bangladeshi women.

    PubMed

    Jamil, Kazi M; Brown, Kenneth H; Jamil, Maleka; Peerson, Janet M; Keenan, Alison H; Newman, John W; Haskell, Marjorie J

    2012-10-01

    We assessed the effect of daily consumption of orange-fleshed sweet potatoes (OFSP), with or without added fat, on the vitamin A (VA) status of Bangladeshi women with low initial VA status. Women (n = 30/group) received one of the following for 6 d/wk over 10 wk: 1) 0 μg retinol activity equivalents (RAE)/d as boiled white-fleshed sweet potatoes (WFSP) and a corn oil capsule, 2) 600 μg RAE/d as boiled OFSP and a corn oil capsule, 3) fried OFSP and a corn oil capsule, or 4) boiled WFSP and a retinyl palmitate capsule in addition to their home diets. Plasma concentrations of retinol and β-carotene and total body VA pool size were assessed before and after the 60-d intervention. Initial and final plasma retinol concentrations (mean ± SD) were 0.75 ± 0.18 μmol/L and 0.84 ± 0.19 μmol/L, respectively (P = 0.31); final means did not differ by group. Initial and final plasma β-carotene concentrations were 0.10 ± 00 μmol/L and 0.18 ± 0.09 μmol/L, respectively (P < 0.0001); final mean plasma β-carotene concentrations were higher in groups that received OFSP (P < 0.0001), and final mean plasma β-carotene was marginally higher in the group that received fried OFSP compared with boiled OFSP (P = 0.07). Initial and final total body VA pool sizes were 0.060 ± 0.047 mmol and 0.091 ± 0.070 mmol, respectively (P = 0.05, n = 110) and did not differ by group. Despite an increase in plasma β-carotene concentration, the impact of OFSP on VA status appears to be limited in Bangladeshi women residing in a resource-poor community. PMID:22933750

  10. Hemangioma of the tongue demonstrating a perfusion blood pool mismatch

    SciTech Connect

    Front, D.; Groshar, D.; Israel, O.; Robinson, E.

    1986-02-01

    Perfusion blood pool mismatch using Tc-99m labeled red blood cells (RBCs) in a hemangioma of the tongue is described. The method is useful in the evaluation of size of the residual blood pool after irradiation of the tumor.

  11. Plantain starch granules morphology, crystallinity, structure transition, and size evolution upon acid hydrolysis.

    PubMed

    Hernández-Jaimes, C; Bello-Pérez, L A; Vernon-Carter, E J; Alvarez-Ramirez, J

    2013-06-01

    Plantain native starch was hydrolysed with sulphuric acid for twenty days. Hydrolysis kinetics was described by a logistic function, with a zero-order rate during the first seven days, followed by a slower kinetics dynamics at longer times. X-ray diffraction results revealed a that gradual increase in crystallinity occurred during the first seven days, followed by a decrease to values similar to those found in the native starch. Differential scanning calorimetry analysis suggested a sharp structure transition by the seventh day probably due to a molecular rearrangement of the starch blocklets and inhomogeneous erosion of the amorphous regions and semi crystalline lamellae. Scanning electron micrographs showed that starch granules morphology was continually degraded from an initial oval-like shape to irregular shapes due to aggregation effects. Granule size distribution broadened as hydrolysis time proceeded probably due to fragmentation and agglomeration phenomena of the hydrolysed starch granules.

  12. The lack of gonadotrophin-releasing hormone (GnRH) receptor desensitisation in alphaT3-1 cells is not due to GnRH receptor reserve or phosphatidylinositol 4,5-bis-phosphate pool size.

    PubMed

    Forrest-Owen, W; Willars, G B; Nahorski, S R; Assefa, D; Davidson, J S; Hislop, J; McArdle, C A

    1999-01-25

    The phospholipase C (PLC)-activating gonadotrophin-releasing hormone (GnRH) receptor is thought not to rapidly desensitise in alphaT3-1 cells. This extremely unusual characteristic raises the concern that it might be a feature of the cell type, rather than the receptor per se. Here we have used video imaging to establish whether the effects of endogenous PLC-activating G-protein coupled receptors (GPCRs) on Ca2+ ion concentration [Ca2+]i desensitise in these cells. Oxytocin, endothelin-1, methacholine, and UTP all caused [Ca2+]i increases which underwent rapid homologous desensitisation in that they were transient and responses to repeat stimuli were attenuated whereas subsequent responses to GnRH were not. To test whether receptor reserve obscures functional desensitisation of GnRH receptors, a photoaffinity antagonist (Pant-1), was used to effect a partial and irreversible receptor blockade. UV crosslinking in medium with 1000 nM Pant-1 reduced GnRH receptor number to 20 +/- 5% and reduced maximal buserelin-stimulated [3H]IP(X) accumulation to 57 +/- 5%, demonstrating removal of receptor reserve. In control alphaT3-1 cells the initial rate of GnRH-stimulated [3H]IP(X) accumulation was maintained for at least 5 min and GnRH caused a sustained increase in Ins(1,4,5)P3 mass (confirming the resistance of GnRH receptors to desensitisation) and Pant-1 pre-treatment reduced the magnitude of these responses without altering their temporal profiles. In alphaT3-1 cells stably transfected with recombinant human muscarinic receptors (alphaT3-1/M3), responses to methacholine were characteristic of desensitising GPCRs (transient Ins(1,4,5)P3 and curvilinear [3H]IP(X) responses) and were unaltered by Pant-1. To test the relevance of phospholipid pool size, alphaT3-1/M3 cells were pre-treated with GnRH or methacholine in medium with LiCl (to deplete PtdIns(4,5)P2 pools). These pre-treatments reduced subsequent responses to methacholine and GnRH comparably, indicating access to a

  13. Shape matters: size-exclusion HPLC for the study of nucleic acid structural polymorphism

    PubMed Central

    Largy, Eric; Mergny, Jean-Louis

    2014-01-01

    In recent years, an increasing number of reports have been focused on the structure and biological role of non-canonical nucleic acid secondary structures. Many of these studies involve the use of oligonucleotides that can often adopt a variety of structures depending on the experimental conditions, and hence change the outcome of an assay. The knowledge of the structure(s) formed by oligonucleotides is thus critical to correctly interpret the results, and gain insight into the biological role of these particular sequences. Herein we demonstrate that size-exclusion HPLC (SE-HPLC) is a simple yet surprisingly powerful tool to quickly and effortlessly assess the secondary structure(s) formed by oligonucleotides. For the first time, an extensive calibration and validation of the use of SE-HPLC to confidently detect the presence of different species displaying various structure and/or molecularity, involving >110 oligonucleotides forming a variety of secondary structures (antiparallel, parallel, A-tract bent and mismatched duplexes, triplexes, G-quadruplexes and i-motifs, RNA stem loops), is performed. Moreover, we introduce simple metrics that allow the use of SE-HPLC without the need for a tedious calibration work. We show that the remarkable versatility of the method allows to quickly establish the influence of a number of experimental parameters on nucleic acid structuration and to operate on a wide range of oligonucleotide concentrations. Case studies are provided to clearly illustrate the all-terrain capabilities of SE-HPLC for oligonucleotide secondary structure analysis. Finally, this manuscript features a number of important observations contributing to a better understanding of nucleic acid structural polymorphism. PMID:25143531

  14. Heat transfer from internally heated hemispherical pools

    SciTech Connect

    Gabor, J.D.; Ellsion, P.G.; Cassulo, J.C.

    1980-01-01

    Experiments were conducted on heat transfer from internally heated ZnSO/sub 4/-H/sub 2/O pools to the walls of hemispherical containers. This experimental technique provides data for a heat transfer system that has to date been only theoretically treated. Three different sizes of copper hemispherical containers were used: 240, 280, 320 mm in diameter. The pool container served both as a heat transfer surface and as an electrode. The opposing electrode was a copper disk, 50 mm in diameter located at the top of the pool in the center. The top surface of the pool was open to the atmosphere.

  15. Size does matter: 18 amino acids at the N-terminal tip of an amino acid transporter in Leishmania determine substrate specificity

    PubMed Central

    Schlisselberg, Doreen; Mazarib, Eldar; Inbar, Ehud; Rentsch, Doris; Myler, Peter J.; Zilberstein, Dan

    2015-01-01

    Long N-terminal tails of amino acid transporters are known to act as sensors of the internal pool of amino acids and as positive regulators of substrate flux rate. In this study we establish that N-termini of amino acid transporters can also determine substrate specificity. We show that due to alternative trans splicing, the human pathogen Leishmania naturally expresses two variants of the proline/alanine transporter, one 18 amino acid shorter than the other. We demonstrate that the longer variant (LdAAP24) translocates both proline and alanine, whereas the shorter variant (∆18LdAAP24) translocates just proline. Remarkably, co-expressing the hydrophilic N-terminal peptide of the long variant with ∆18LdAAP24 was found to recover alanine transport. This restoration of alanine transport could be mediated by a truncated N-terminal tail, though truncations exceeding half of the tail length were no longer functional. Taken together, the data indicate that the first 18 amino acids of the negatively charged N-terminal LdAAP24 tail are required for alanine transport and may facilitate the electrostatic interactions of the entire negatively charged N-terminal tail with the positively charged internal loops in the transmembrane domain, as this mechanism has been shown to underlie regulation of substrate flux rate for other transporters. PMID:26549185

  16. Swimming Pools, Hot Rods, and Qualitative Analysis.

    ERIC Educational Resources Information Center

    Clyde, Dale D.

    1988-01-01

    Describes some reactions for the identification and application of cyanuric acid. Suggests students may find this applied chemistry interesting because of the use of cyanuric acid in swimming pools and diesel engines. Lists three tests for cyanate ion and two tests for cyanuric acid. (MVL)

  17. Dicarboxylic acids, ω-oxocarboxylic acids, α-dicarbonyls, WSOC, OC, EC, and inorganic ions in wintertime size-segregated aerosols from central India: Sources and formation processes.

    PubMed

    Deshmukh, Dhananjay K; Kawamura, Kimitaka; Deb, Manas K

    2016-10-01

    The size distributions of aerosols can provide evidences for their sources and formation processes in the atmosphere. Size-segregated aerosols (9-sizes) were collected in urban site (Raipur: 21.2°N and 82.3°E) in central India during winter of 2012-2013. The samples were analyzed for dicarboxylic acids (C2-C12), ω-oxocarboxylic acids (ωC2-ωC9), pyruvic acid and α-dicarbonyls (C2-C3) as well as elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC) and inorganic ions. Diacids showed a predominance of oxalic acid (C2) followed by succinic and azelaic acid whereas ω-oxoacids exhibited a predominance of glyoxylic acid and glyoxal was more abundant than methylglyoxal in all the sizes. Diacids, ω-oxoacids and α-dicarbonyls showed bimodal size distribution with peaks in fine and coarse modes. High correlations of fine mode diacids and related compounds with potassium and levoglucosan suggest that they were presumably due to a substantial contribution of primary emission from biomass burning and secondary production from biomass burning derived precursors. High correlations of C2 with higher carbon number diacids (C3-C9) suggest that they have similar sources and C2 may be produced via the decay of its higher homologous diacids in fine mode. Considerable portions of diacids and related compounds in coarse mode suggest that they were associated with mineral dust particles by their adsorption and photooxidation of anthropogenic and biogenic precursors via heterogeneous reaction on dust surface. This study demonstrates that biomass burning and dust particles are two major factors to control the size distribution of diacids and related compounds in the urban aerosols from central India. PMID:27414241

  18. The science of pooling

    SciTech Connect

    Gilbert, E.

    1995-10-01

    The pooling of data from radon studies is described. Pooling refers to the analysis of original data from several studies, not meta-analysis in which summary measures from published data are analyzed. A main objective for pooling is to reduce uncertainty and to obtain more precise estimates of risk than would be available from any single study.

  19. Effect of particle size reduction, hydrothermal and fermentation treatments on phytic acid content and some physicochemical properties of wheat bran.

    PubMed

    Majzoobi, Mahsa; Pashangeh, Safoora; Farahnaky, Asgar; Eskandari, Mohammad Hadi; Jamalian, Jalal

    2014-10-01

    With the aim of reducing phytic acid content of wheat bran, particle size reduction (from 1,200 to 90 μm), hydrothermal (wet steeping in acetate buffer at pH 4.8 at 55 °C for 60 min) and fermentation (using bakery yeast for 8 h at 30 °C) and combination of these treatments with particle size reduction were applied and their effects on some properties of the bran were studied. Phytic acid content decreased from 50.1 to 21.6, 32.8 and 43.9 mg/g after particle size reduction, hydrothermal and fermentation, respectively. Particle size reduction along with these treatments further reduced phytic acid content up to 76.4 % and 57.3 %, respectively. Hydrothermal and fermentation decreased, while particle size reduction alone or in combination increased bran lightness. With reducing particle size, total, soluble and insoluble fiber content decreased from 69.7 to 32.1 %, 12.2 to 7.9 % and 57.4 to 24.3 %, respectively. The highest total (74.4 %) and soluble (21.4 %) and the lowest insoluble fiber (52.1 %) content were determined for the hydrothermaled bran. Particle size reduction decreased swelling power, water solubility and water holding capacity. Swelling power and water holding capacity of the hydrothermaled and fermented brans were lower, while water solubility was higher than the control. The amount of Fe(+2), Zn(+2) and Ca(+2) decreased with reducing particle size. Fermentation had no effect on Fe(+2)and Zn(+2) but slightly reduced Ca(+2). The hydrothermal treatment slightly decreased these elements. Amongst all, hydrothermal treatment along with particle size reduction resulted in the lowest phytic acid and highest fiber content. PMID:25328222

  20. Smart Superstructures with Ultrahigh pH-Sensitivity for Targeting Acidic Tumor Microenvironment: Instantaneous Size Switching and Improved Tumor Penetration.

    PubMed

    Li, Hong-Jun; Du, Jin-Zhi; Liu, Jing; Du, Xiao-Jiao; Shen, Song; Zhu, Yan-Hua; Wang, Xiaoyan; Ye, Xiaodong; Nie, Shuming; Wang, Jun

    2016-07-26

    The currently low delivery efficiency and limited tumor penetration of nanoparticles remain two major challenges of cancer nanomedicine. Here, we report a class of pH-responsive nanoparticle superstructures with ultrasensitive size switching in the acidic tumor microenvironment for improved tumor penetration and effective in vivo drug delivery. The superstructures were constructed from amphiphilic polymer directed assembly of platinum-prodrug conjugated polyamidoamine (PAMAM) dendrimers, in which the amphiphilic polymer contains ionizable tertiary amine groups for rapid pH-responsiveness. These superstructures had an initial size of ∼80 nm at neutral pH (e.g., in blood circulation), but once deposited in the slightly acidic tumor microenvironment (pH ∼6.5-7.0), they underwent a dramatic and sharp size transition within a very narrow range of acidity (less than 0.1-0.2 pH units) and dissociated instantaneously into the dendrimer building blocks (less than 10 nm in diameter). This rapid size-switching feature not only can facilitate nanoparticle extravasation and accumulation via the enhanced permeability and retention effect but also allows faster nanoparticle diffusion and more efficient tumor penetration. We have further carried out comparative studies of pH-sensitive and insensitive nanostructures with similar size, surface charge, and chemical composition in both multicellular spheroids and poorly permeable BxPC-3 pancreatic tumor models, whose results demonstrate that the pH-triggered size switching is a viable strategy for improving drug penetration and therapeutic efficacy.

  1. poolMC: Smart pooling of mRNA samples in microarray experiments

    PubMed Central

    2010-01-01

    Background Typically, pooling of mRNA samples in microarray experiments implies mixing mRNA from several biological-replicate samples before hybridization onto a microarray chip. Here we describe an alternative smart pooling strategy in which different samples, not necessarily biological replicates, are pooled in an information theoretic efficient way. Further, each sample is tested on multiple chips, but always in pools made up of different samples. The end goal is to exploit the compressibility of microarray data to reduce the number of chips used and increase the robustness to noise in measurements. Results A theoretical framework to perform smart pooling of mRNA samples in microarray experiments was established and the software implementation of the pooling and decoding algorithms was developed in MATLAB. A proof-of-concept smart pooled experiment was performed using validated biological samples on commercially available gene chips. Differential-expression analysis of the smart pooled data was performed and compared against the unpooled control experiment. Conclusions The theoretical developments and experimental demonstration in this paper provide a useful starting point to investigate smart pooling of mRNA samples in microarray experiments. Although the smart pooled experiment did not compare favorably with the control, the experiment highlighted important conditions for the successful implementation of smart pooling - linearity of measurements, sparsity in data, and large experiment size. PMID:20525223

  2. Particle size distributions in Arctic polar stratospheric clouds, growth and freezing of sulfuric acid droplets, and implications for cloud formation

    NASA Technical Reports Server (NTRS)

    Dye, James E.; Baumgardner, D.; Gandrud, B. W.; Kawa, S. R.; Kelly, K. K.; Loewenstein, M.; Ferry, G. V.; Chan, K. R.; Gary, B. L.

    1992-01-01

    The paper uses particle size and volume measurements obtained with the forward scattering spectrometer probe model 300 during January and February 1989 in the Airborne Arctic Stratospheric Experiment to investigate processes important in the formation and growth of polar stratospheric cloud (PSC) particles. It is suggested on the basis of comparisons of the observations with expected sulfuric acid droplet deliquescence that in the Arctic a major fraction of the sulfuric acid droplets remain liquid until temperatures at least as low as 193 K. It is proposed that homogeneous freezing of the sulfuric acid droplets might occur near 190 K and might play a role in the formation of PSCs.

  3. 13 CFR 120.611 - Pools backing Pool Certificates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Pools backing Pool Certificates... Secondary Market Certificates § 120.611 Pools backing Pool Certificates. (a) Pool characteristics. As set forth in the Program Guide, each Pool must have: (1) A minimum number of guaranteed portions of...

  4. 13 CFR 120.611 - Pools backing Pool Certificates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Pools backing Pool Certificates... Secondary Market Certificates § 120.611 Pools backing Pool Certificates. (a) Pool characteristics. As set forth in the Program Guide, each Pool must have: (1) A minimum number of guaranteed portions of...

  5. 13 CFR 120.611 - Pools backing Pool Certificates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Pools backing Pool Certificates... Secondary Market Certificates § 120.611 Pools backing Pool Certificates. (a) Pool characteristics. As set forth in the Program Guide, each Pool must have: (1) A minimum number of guaranteed portions of...

  6. 13 CFR 120.611 - Pools backing Pool Certificates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Pools backing Pool Certificates... Secondary Market Certificates § 120.611 Pools backing Pool Certificates. (a) Pool characteristics. As set forth in the Program Guide, each Pool must have: (1) A minimum number of guaranteed portions of...

  7. 13 CFR 120.611 - Pools backing Pool Certificates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Pools backing Pool Certificates... Secondary Market Certificates § 120.611 Pools backing Pool Certificates. (a) Pool characteristics. As set forth in the Program Guide, each Pool must have: (1) A minimum number of guaranteed portions of...

  8. Performance Study and Dynamic Optimization Design for Thread Pool Systems

    SciTech Connect

    Dongping Xu

    2004-12-19

    Thread pools have been widely used by many multithreaded applications. However, the determination of the pool size according to the application behavior still remains problematic. To automate this process, in this thesis we have developed a set of performance metrics for quantitatively analyzing thread pool performance. For our experiments, we built a thread pool system which provides a general framework for thread pool research. Based on this simulation environment, we studied the performance impact brought by the thread pool on different multithreaded applications. Additionally, the correlations between internal characterizations of thread pools and their throughput were also examined. We then proposed and evaluated a heuristic algorithm to dynamically determine the optimal thread pool size. The simulation results show that this approach is effective in improving overall application performance.

  9. Size distributions of dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids in atmospheric aerosols from Tanzania, East Africa during wet and dry seasons

    NASA Astrophysics Data System (ADS)

    Mkoma, S. L.; Kawamura, K.

    2012-09-01

    Atmospheric aerosol samples of PM2.5 and PM10 were collected during the wet and dry seasons in 2011 from a rural site in Tanzania and analysed for water-soluble dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls and fatty acids using a gas chromatography (GC) and GC/mass spectrometry. Here we report the size distribution and sources of diacids and related compounds for wet and dry seasons. Oxalic acid (C2) was found as the most abundant diacid species followed by succinic and/or malonic acids whereas glyoxylic acid and glyoxal were the dominant ketoacids and α-dicarbonyls, respectively in both seasons in PM2.5 and PM10. Mean concentration of C2 in PM2.5 (121.5± 46.6 ng m-3) was lower in wet season than dry season (258.1± 69.5 ng m-3). Similarly, PM10 samples showed lower concentration of C2 (168.6 ± 42.4 ng m-3) in wet season than dry season (292.4± 164.8 ng m-3). Relative abundances of C2 in total diacids were 65.4% and 67.1% in PM2.5 and 64.6% and 63.9% in PM10 in the wet and dry seasons, respectively. Total concentrations of diacids (289-362 m-3), ketoacids (37.8-53.7ng m-3), and α-dicarbonyls (5.7-7.8 ng m-3) in Tanzania are higher to those reported at a rural background site in Nylsvley (South Africa) but comparable or lower to those reported from sites in Asia and Europe. Diacids and ketoacids were found to be present mainly in the fine fraction in both seasons (total α-dicarbonyls in the dry season), suggesting a production of organic aerosols from pyrogenic sources and photochemical oxidations. The averaged contributions of total diacid carbon to aerosol total carbon were 1.4% in PM2.5 and 2.1% in PM10 in wet season and 3.3% in PM2.5 and 3.9% in PM10 in dry season whereas those to water-soluble organic carbon were 2.2% and 4.7% inPM2.5 and 3.1% and 5.8% in PM10 during the wet and dry seasons, respectively. These ratios suggest an enhanced photochemical oxidation of organic precursors and heterogeneous reactions on aerosols under strong solar

  10. Structure and Energetics of Nanometer Size Clusters of Sulfuric Acid with Ammonia and Dimethylamine

    SciTech Connect

    Depalma, Joseph W.; Bzdek, Bryan R.; Doren, Doug J.; Johnston, Murray V.

    2012-01-26

    The structures of positively and negatively charged clusters of sulfuric acid with ammonia and/or dimethylamine ((CH{sub 3}){sub 2}NH or DMA) are investigated using a combination of Monte Carlo configuration sampling, semiempirical calculations, and density functional theory (DFT) calculations. Positively charged clusters of the formula [(NH{sub 4}{sup +}){sub x}(HSO{sub 4}{sup -}){sub y}]{sup +}, where x = y + 1, are studied for 1 {le} y {le} 10. These clusters exhibit strong cation-anion interactions, with no contribution to the hydrogen-bonding network from the bisulfate ion protons. A similar hydrogen-bonding network is found for the [(DMAH{sup +}){sub 5}(HSO{sub 4}{sup -}){sub 4}]{sup -} cluster. Negatively charged clusters derived from the reaction of DMA with [(H{sub 2}SO{sub 4}){sub 3}(NH{sub 4}{sup +})(HSO{sub 4}{sup -}){sub 2}]{sup -} are also studied, up to the fully reacted cluster [(DMAH{sup +}){sub 4}(HSO{sub 4}{sup -}){sub 5}]{sup -}. These clusters exhibit anion-anion and ion-molecule interactions in addition to cation-anion interactions. While the hydrogen-bonding network is extensive for both positively and negatively charged clusters, the binding energies of ions and molecules in these clusters are determined mostly by electrostatic interactions. The thermodynamics of amine substitution is explored and compared to experimental thermodynamic and kinetic data. Ammonia binds more strongly than DMA to sulfuric acid due to its greater participation in hydrogen bonding and its ability to form a more compact structure that increases electrostatic attraction between oppositely charged ions. However, the greater gas-phase basicity of DMA is sufficient to overcome the stronger binding of ammonia, making substitution of DMA for ammonia thermodynamically favorable. For small clusters of both polarities, substitutions of surface ammonium ions are facile. As the cluster size increases, an ammonium ion becomes encapsulated in the center of the cluster, making

  11. Cold pool dissipation

    NASA Astrophysics Data System (ADS)

    Grant, Leah D.; Heever, Susan C.

    2016-02-01

    The mechanisms by which sensible heat fluxes (SHFs) alter cold pool characteristics and dissipation rates are investigated in this study using idealized two-dimensional numerical simulations and an environment representative of daytime, dry, continental conditions. Simulations are performed with no SHFs, SHFs calculated using a bulk formula, and constant SHFs for model resolutions with horizontal (vertical) grid spacings ranging from 50 m (25 m) to 400 m (200 m). In the highest resolution simulations, turbulent entrainment of environmental air into the cold pool is an important mechanism for dissipation in the absence of SHFs. Including SHFs enhances cold pool dissipation rates, but the processes responsible for the enhanced dissipation differ depending on the SHF formulation. The bulk SHFs increase the near-surface cold pool temperatures, but their effects on the overall cold pool characteristics are small, while the constant SHFs influence the near-surface environmental stability and the turbulent entrainment rates into the cold pool. The changes to the entrainment rates are found to be the most significant of the SHF effects on cold pool dissipation. SHFs may also influence the timing of cold pool-induced convective initiation by altering the environmental stability and the cold pool intensity. As the model resolution is coarsened, cold pool dissipation is found to be less sensitive to SHFs. Furthermore, the coarser resolution simulations not only poorly but sometimes wrongly represent the SHF impacts on the cold pools. Recommendations are made regarding simulating the interaction of cold pools with convection and the land surface in cloud-resolving models.

  12. Size distributions of nano/micron dicarboxylic acids and inorganic ions in suburban PM episode and non-episodic aerosol

    NASA Astrophysics Data System (ADS)

    Hsieh, Li-Ying; Kuo, Su-Ching; Chen, Chien-Lung; Tsai, Ying I.

    The distribution of nano/micron dicarboxylic acids and inorganic ions in size-segregated suburban aerosol of southern Taiwan was studied for a PM episode and a non-episodic pollution period, revealing for the first time the distribution of these nanoscale particles in suburban aerosols. Inorganic species, especially nitrate, were present in higher concentrations during the PM episode. A combination of gas-to-nuclei conversion of nitrate particles and accumulation of secondary photochemical products originating from traffic-related emissions was likely a crucial cause of the PM episode. Sulfate, ammonium, and oxalic acid were the dominant anion, cation, and dicarboxylic acid, respectively, accounting for a minimum of 49% of the total anion, cation or dicarboxylic acid mass. Peak concentrations of these species occurred at 0.54 μm in the droplet mode during both non-episodic and PM episode periods, indicating an association with cloud-processed particles. On average, sulfate concentration was 16-17 times that of oxalic acid. Oxalic acid was nevertheless the most abundant dicarboxylic acid during both periods, followed by succinic, malonic, maleic, malic and tartaric acid. The mass median aerodynamic diameter (MMAD) of oxalic acid was 0.77 μm with a bi-modal presence at 0.54 μm and 18 nm during non-episodic pollution and an MMAD of 0.67 μm with mono-modal presence at 0.54 μm in PM episode aerosol. The concomitant formation of malonic acid and oxalic acid was attributed to in-cloud processes. During the PM episode in the 5-100 nm nanoscale range, an oxalic acid/sulfate mass ratio of 40.2-82.3% suggested a stronger formation potential for oxalic acid than for sulfate in the nuclei mode. For total cations (TC), total inorganic anions (TIA) and total dicarboxylic acids (TDA), major contributing particles were in the droplet mode, with least in the nuclei mode. The ratio of TDA to TIA in the nuclei mode increased greatly from 8.40% during the non-episodic pollution

  13. Water-soluble dicarboxylic acids and ω-oxocarboxylic acids in size-segregated aerosols over northern Japan during spring: sources and formation processes

    NASA Astrophysics Data System (ADS)

    Deshmukh, Dhananjay Kumar; Kawamura, Kimitaka; Kobayashi, Minoru; Gowda, Divyavani

    2016-04-01

    Seven sets (AF01-AF07) of size-segregated aerosol (12-sizes) samples were collected using a Micro-Orifice Uniform Deposit Impactor (MOUDI) in Sapporo, Japan during the spring of 2001 to understand the sources and atmospheric processes of water-soluble organic aerosols in the outflow region of Asian dusts. The samples were analyzed for dicarboxylic acids (C2-C12) and ω-oxocarboxylic acids as well as inorganic ions. The molecular distribution of diacids showed the predominance of oxalic acid (C2) followed by malonic and succinic acids whereas ω-oxoacids showed the predominance of glyoxylic acid (ωC2) in size-segregated aerosols. SO42- and NH4+ are enriched in submicron mode whereas NO3- and Ca2+ are in supermicron mode. Most of diacids and ω-oxoacids are enriched in supermicron mode in the samples (AF01-AF03) influenced by the long-range transport of mineral dusts whereas enhanced presence in submicron mode was observed in other sample sets. The strong correlations of C2 with Ca2+ (r = 0.95-0.99) and NO3- (r = 0.96-0.98) in supermicron mode in the samples AF01-AF03 suggest the adsorption or production of C2 diacid via heterogeneous reaction on the surface of mineral dust during long-range atmospheric transport. The preferential enrichment of diacids and ω-oxoacids in mineral dust has important implications for the solubility and cloud nucleation properties of the dominant fraction of water-soluble organic aerosols. This study demonstrates that biofuel and biomass burning and mineral dust originated in East Asia are two major factors to control the size distribution of diacids and related compounds over northern Japan.

  14. Structure of polyglycerol oleic acid ester nonionic surfactant reverse micelles in decane: growth control by headgroup size.

    PubMed

    Shrestha, Lok Kumar; Dulle, Martin; Glatter, Otto; Aramaki, Kenji

    2010-05-18

    The structure of polyglycerol oleic acid ester nonionic surfactant micelles in n-decane has been investigated at room temperature by small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and densiometry techniques. The scattering data were evaluated by indirect Fourier transformation (IFT) or generalized indirect Fourier transformation (GIFT) methods depending on the volume fractions of the surfactants and also by model fit. A simple route to the growth control of reverse micelles by headgroup size of the surfactant was investigated. Additionally, the dependence of reverse micellar structure (shape and size) on temperature, composition, and added water was also investigated. The indirect Fourier transformation gives the real space pair-distance distribution function, p(r): a facile way for the quantitative estimation of structure parameters of the aggregates. It was found that the size of the reverse micelles increases with increasing the headgroup size of the surfactant. Globular type of micelles with maximum diameter ca. 6 nm observed in the monoglycerol oleic acid ester/decane system at 25 degrees C transferred into elongated prolate type micelles with maximum diameter ca. 19.5 nm in the hexaglycerol oleic acid ester/decane system. In a particular surfactant and oil system, increasing temperature decreased the micellar size. The size of the micelle was decreased by approximately 25% upon increasing temperature from 25 to 75 degrees C in the 5 wt % diglycerol oleic acid ester/decane system. Concentration could not modulate the structure of micelles despite a wide variation in the surfactant concentration (5-25 wt %). Nevertheless, increasing surfactant concentration reduces the intermicellar distance, and a strong repulsive interaction peak was observed in the scattering curves at higher surfactant concentrations. Besides, the results obtained from the dynamic light scattering have shown the signature of diffusion hindrance relative to hard sphere

  15. Mathematical model for evaluating the Krebs cycle flux with non-constant glutamate-pool size by 13C-NMR spectroscopy. Evidence for the existence of two types of Krebs cycles in cells.

    PubMed

    Tran-Dinh, S; Beganton, F; Nguyen, T T; Bouet, F; Herve, M

    1996-12-01

    A practical method using matrix operations is proposed for studying the isotopic transformation of glutamate, or any other metabolite isotopomers, in the Krebs cycle. Two mathematical models were constructed for evaluating the Krebs cycle flux where the enrichment of [2-13C]acetyl-CoA is not 100% and the total glutamate concentration remains constant or varies during incubation. A comparative study of [1-13C]glucose metabolism was subsequently carried out using Saccharomyces cerevisiae cells from two different strains (ATCC-9763 and NCYC-239) by 13C-NMR spectroscopy and biochemical techniques. The results show that there are two types of Krebs cycles in cells. The first is represented by the ATCC cells which contain a small amount of 2-oxoglutarate dehydrogenase and hence the flux in the Krebs cycle is negligible. With [1-13C]glucose as a carbon source, the 13C-NMR spectra of glutamate exhibit the C2 and C4 resonances that are almost equivalent and much greater than that of the C3. Labeled metabolites derived from [1-13C]glucose enter the Krebs cycle at two points: oxaloacetate and citrate. The second cell type is represented by NCYC-239. The C2 and C3 areas are equivalent and smaller than the C4 resonance. The results suggest that labeled metabolites enter the Krebs cycle only at the citrate level via acetyl-CoA, 2-oxoglutarate dehydrogenase is present but pyruvate carboxylase is virtually absent or inactivated. When both are incubated with glucose, the total concentration of glutamate was found to decrease with the incubation time. The fraction of glutamate in isotopic exchange with the Krebs cycle in NCYC-239 cells is about 2.6% and the reduction in glutamate concentration is about 0.5%/min. Using our model, with a variable glutamate pool size, good agreement between the theoretical and experimental data is obtained.

  16. Complementary use of flow and sedimentation field-flow fractionation techniques for size characterizing biodegradable poly(lactic acid) nanospheres

    PubMed Central

    Contado, Catia; Dalpiaz, Alessandro; Leo, Eliana; Zborowski, Maciej; Williams, P. Stephen

    2009-01-01

    Poly(lactic acid) nanoparticles were synthesized using a modified evaporation method, testing two different surfactants (sodium cholate and Pluronic F68) for the process. During their formulation the prodrug 5′-octanoyl-CPA (Oct-CPA) of the antiischemic N6-cyclopentyladenosine (CPA) was encapsulated. Three different purification methods were compared with respect to the influence of surfactant on the size characteristics of the final nanoparticle product. Flow and sedimentation field-flow fractionation techniques (FlFFF and SdFFF, respectively) were used to size characterize the five poly(lactic acid) particle samples. Two different combinations of carrier solution (mobile phase) were employed in the FlFFF analyses, while a solution of poly(vinyl alcohol) was used as mobile phase for the SdFFF runs. The separation performances of the two techniques were compared and the particle size distributions, derived from the fractograms, were interpreted with the support of observations by scanning electron microscopy. Some critical aspects, such as the carrier choice and the channel thickness determination for the FlFFF, have been investigated. This is the first comprehensive comparison of the two FFF techniques for characterizing non standard particulate materials. The two FFF techniques proved to be complementary and gave good, congruent and very useful information on the size distributions of the five poly(lactic acid) particle samples. PMID:17482199

  17. Particle size conditions water repellency in sand samples hydrophobized with stearic acid

    NASA Astrophysics Data System (ADS)

    González-Peñaloza, F. A.; Jordán, A.; Bellinfante, N.; Bárcenas-Moreno, G.; Mataix-Solera, J.; Granged, A. J. P.; Gil, J.; Zavala, L. M.

    2012-04-01

    The main objective of this research is to study the effects of particle size and soil moisture on water repellency (WR) from hydrophobized sand samples. Quartz sand samples were collected from the top 15 cm of sandy soils, homogenised and divided in different sieve fractions: 0.5 - 2 mm (coarse sand), 0.25 - 0.5 mm (medium sand), and 0.05 - 0.25 mm (fine sand). WR was artificially induced in sand samples using different concentrations of stearic acid (SA; 0.5, 1, 5, 10, 20 and 30 g kg-1). Sand samples were placed in Petri plates and moistened with distilled water until 10% water content in weight. After a period of 30 min, soil WR was determined using the water drop penetration time (WDPT) test. A set of sub-samples was placed in an oven (50 oC) during the experimental period, and the rest was left air-drying at standard laboratory conditions. Water repellent soil samples were used as control, and the same treatments were applied. WR was determined every 24 h. No changes in WR were observed after 6 days of treatment. As expected, air-dried fine sand samples showed WR increasing with SA concentration and decreasing with soil moisture. In contrast, oven-dried samples remained wettable at SA concentrations below 5 g kg-1. Fine sand oven-dried samples showed extreme WR after just one day of treatment, but air-dried samples did not show extreme repellency until three days after treatment. SA concentrations above 5 g kg-1 always induced extreme WR. Medium sand air-dried samples showed hydrophilic properties when moist and low SA concentration (£1 g kg-1), but strong to extreme WR was induced by higher SA concentrations. In the case of oven-dried samples, medium sand showed severe to extreme WR regardless of soil moisture. Coarse sand showed the longest WDPTs, independently of soil moisture content or SA concentration. This behaviour may be caused by super-hydrophobicity. Also, it is suggested that movements of sand particles during wetting, contribute to expose new

  18. Particle Size (Sieving) and Enthalpy (Acid Calorimetry) Analysis of Single-Pull K East Basin Floor and Pit Sludges

    SciTech Connect

    PR Bredt; CH Delegard; AJ Schmidt; KL Silvers; BM Thornton; S Gano

    2000-12-22

    This report presents the results of particle size analyses and calorimetry testing performed on selected single-pull sludge samples collected from the Hanford K East Basin between December 1998 and June 1999. The samples were collected as isolated cores predominantly from areas that had not been previously sampled (e.g., North Loadout Pit, Dummy Elevator Pit, Tech View Pit), or from areas in which the sludge composition had been altered since the last sampling (e.g., Weasel Pit). Particle size analyses were performed by washing wet sludge samples through a series of four sieves with openings of 250, 500, 1410, and 4000 {micro}m. The loaded sieves were weighed before and after drying to obtain wet and dry particle size distributions. Knowledge of the particle size distribution is needed to design and predict the performance of the systems that will be used to retrieve, transport, and recover sludge. Also, sieving provides an opportunity to observe the components in the sludge. For example, during sieving of the sludge sample from the North Loadout Pit, significant quantities of organic ion exchange beads were observed. The uranium metal content and the particle size of the uranium metal in the K Basin sludge will largely determine the chemical reactivity of the sludge. In turn, the designs for the sludge handling and storage systems must be compatible with the reactivity of the sludge. Therefore, acid calorimetry was performed to estimate the uranium metal content of the sludge. For this testing, sludge samples were dissolved in nitric acid within a calibrated adiabatic calorimeter. The resulting dissolution enthalpy data were then used to discriminate between metallic uranium ({minus}3750 J/g in nitric acid) and uranium oxide ({minus}394 J/g in nitric acid). Results from this testing showed that the single-pull sludge samples contained little or no uranium metal.

  19. Ion balances of size-resolved tropospheric aerosol samples: implications for the acidity and atmospheric processing of aerosols

    NASA Astrophysics Data System (ADS)

    Kerminen, Veli-Matti; Hillamo, Risto; Teinilä, Kimmo; Pakkanen, Tuomo; Allegrini, Ivo; Sparapani, Roberto

    A large set of size-resolved aerosol samples was inspected with regard to their ion balance to shed light on how the aerosol acidity changes with particle size in the lower troposphere and what implications this might have for the atmospheric processing of aerosols. Quite different behaviour between the remote and more polluted environments could be observed. At the remote sites, practically the whole accumulation mode had cation-to-anion ratios clearly below unity, indicating that these particles were quite acidic. The supermicron size range was considerably less acidic and may in some cases have been close to neutral or even alkaline. An interesting feature common to the remote sites was a clear jump in the cation-to-anion ratio when going from the accumulation to the Aitken mode. The most likely reason for this was cloud processing which, via in-cloud sulphate production, makes the smallest accumulation-mode particles more acidic than the non-activated Aitken-mode particles. A direct consequence of the less acidic nature of the Aitken mode is that it can take up semi-volatile, water-soluble gases much easier than the accumulation mode. This feature may have significant implications for atmospheric cloud condensation nuclei production in remote environments. In rural and urban locations, the cation-to-anion ratio was close to unity over most of the accumulation mode, but increased significantly when going to either larger or smaller particle sizes. The high cation-to-anion ratios in the supermicron size range were ascribed to carbonate associated with mineral dust. The ubiquitous presence of carbonate in these particles indicates that they were neutral or alkaline, making them good sites for heterogeneous reactions involving acidic trace gases. The high cation-to-anion ratios in the Aitken mode suggest that these particles contained some water-soluble anions not detected by our chemical analysis. This is worth keeping in mind when investigating the hygroscopic

  20. Swimming pool. View of aisle between swimming pool and seating ...

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

    Swimming pool. View of aisle between swimming pool and seating area. Non-original spa pool is partially visible on right. - Jewish Community Center of San Francisco, 3200 California Street, San Francisco, San Francisco County, CA

  1. 13 CFR 120.1704 - Pool Loans eligible for Pooling.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., construction or renovation of an aquarium, zoo, golf course, or swimming pool; or (iv) To a business covered by... zoos—712130 (“Zoos and Botanical Gardens”). (b) SBA review of a Pool Loan prior to pool formation....

  2. 13 CFR 120.1704 - Pool Loans eligible for Pooling.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., construction or renovation of an aquarium, zoo, golf course, or swimming pool; or (iv) To a business covered by... zoos—712130 (“Zoos and Botanical Gardens”). (b) SBA review of a Pool Loan prior to pool formation....

  3. 13 CFR 120.1704 - Pool Loans eligible for Pooling.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., construction or renovation of an aquarium, zoo, golf course, or swimming pool; or (iv) To a business covered by... zoos—712130 (“Zoos and Botanical Gardens”). (b) SBA review of a Pool Loan prior to pool formation....

  4. 13 CFR 120.1704 - Pool Loans eligible for Pooling.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., construction or renovation of an aquarium, zoo, golf course, or swimming pool; or (iv) To a business covered by... zoos—712130 (“Zoos and Botanical Gardens”). (b) SBA review of a Pool Loan prior to pool formation....

  5. 13 CFR 120.1704 - Pool Loans eligible for Pooling.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., construction or renovation of an aquarium, zoo, golf course, or swimming pool; or (iv) To a business covered by... zoos—712130 (“Zoos and Botanical Gardens”). (b) SBA review of a Pool Loan prior to pool formation....

  6. Prolonged in vivo circulation time by zwitterionic modification of magnetite nanoparticles for blood pool contrast agents.

    PubMed

    Xiao, Wangchuan; Lin, Jiang; Li, Mingli; Ma, Yongjie; Chen, Yuxin; Zhang, Chunfu; Li, Dan; Gu, Hongchen

    2012-01-01

    Long circulation time is critical for blood pool contrast agents used in high-resolution magnetic resonance angiography. For iron oxide particle contrast agents, size and surface properties significantly influence their in vivo performance. We developed a novel long-circulating blood pool contrast agent by introducing zwitterionic structure onto the particle surface. Zwitterionic structure was fabricated by 3-(diethylamino)propylamine (DEAPA) grafted onto the surface of ployacrylic acid coated magnetite nanoparticles via EDC/NHS [N-(3-dimethylaminopropyl)-N'-ethylcarbo-diimide hydrochloride/N-hydroxysuccinimide] coupling chemistry. Zwitterionic particles demonstrated five times lower macrophage cell uptake than the original particles and low cell toxicity. Magnetic resonance angiography indicated that zwitterionic nanoparticles had much longer in vivo circulation time than the original particles and were an ideal candidate for blood pool contrast agent. We suppose that zwitterionic modification by DEAPA and EDC/NHS can be used generally for coating nanoparticles with carboxyl surface and to prolong their circulating time.

  7. Utilization of an evaporative light scattering detector for high-performance size-exclusion chromatography of galacturonic acid oligomers.

    PubMed

    Cameron, Randall G; Hotchkiss, Arland T; Kauffman, Steven W; Grohmann, Karel

    2003-09-01

    A high-performance size-exclusion chromatography-evaporative light scattering detector method was used to separate, detect and quantify galacturonic acid (GA) oligomers. In 40 mM acetic acid GA monomer, dimer and trimer could be separated with baseline resolution but polygalacturonic acid (PGA) precipitated and could not be eluted from the column. An NH4OAc, pH 3.7, buffer was developed as the eluent which separated GA oligomers as well as PGA and pectin without precipitation. Linear calibration curves for mono-, di- and tri-GA were produced with this buffer which could be used to estimate masses of tetra-, penta- and hexa-GA, as well as 19mer and 20mer.

  8. Effect of acid, steam explosion, and size reduction pretreatments on bio-oil production from sweetgum, switchgrass, and corn stover.

    PubMed

    Wang, Hui; Srinivasan, Radhakrishnan; Yu, Fei; Steele, Philip; Li, Qi; Mitchell, Brian; Samala, Aditya

    2012-05-01

    Bio-oil produced from biomass by fast pyrolysis has the potential to be a valuable substitute for fossil fuels. In a recent work on pinewood, we found that pretreatment alters the structure and chemical composition of biomass, which influence fast pyrolysis. In this study, we evaluated dilute acid, steam explosion, and size reduction pretreatments on sweetgum, switchgrass, and corn stover feedstocks. Bio-oils were produced from untreated and pretreated feedstocks in an auger reactor at 450 °C. The bio-oil's physical properties of pH, water content, acid value, density, and viscosity were measured. The chemical characteristics of the bio-oils were determined by gas chromatography-mass spectrometry. The results showed that bio-oil yield and composition were influenced by the pretreatment method and feedstock type. Bio-oil yields of 52, 33, and 35 wt% were obtained from medium-sized (0.68-1.532 mm) untreated sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from other sizes. Bio-oil yields of 56, 46, and 51 wt% were obtained from 1% H(2)SO(4)-treated medium-sized sweetgum, switchgrass, and corn stover, respectively, which were higher than the yields from untreated and steam explosion treatments.

  9. Pools for the Handicapped.

    ERIC Educational Resources Information Center

    American School and University, 1979

    1979-01-01

    Three institutions in Ohio now stress hydrotherapy and water recreation as important parts of individual educational programs for the handicapped. Specially designed and adapted pools provide freedom of movement and ego building as well as physical education and recreation. (Author)

  10. Vitamin D Pooling Project

    Cancer.gov

    The Vitamin D Pooling Project of Rarer Cancers brought together investigators from 10 cohorts to conduct a large prospective epidemiologic study of the association between vitamin D status and seven rarer cancers.

  11. Weld pool phenomena

    SciTech Connect

    David, S.A.; Vitek, J.M.; Zacharia, T.; DebRoy, T.

    1994-09-01

    During welding, the composition, structure and properties of the welded structure are affected by the interaction of the heat source with the metal. The interaction affects the fluid flow, heat transfer and mass transfer in the weld pool, and the solidification behavior of the weld metal. In recent years, there has been a growing recognition of the importance of the weld pool transport processes and the solid state transformation reactions in determining the composition, structure and properties of the welded structure. The relation between the weld pool transport processes and the composition and structure is reviewed. Recent applications of various solidification theories to welding are examined to understand the special problems of weld metal solidification. The discussion is focussed on the important problems and issues related to weld pool transport phenomena and solidification. Resolution of these problems would be an important step towards a science based control of composition, structure and properties of the weld metal.

  12. Swimming pool granuloma

    MedlinePlus

    Aquarium granuloma; Fish tank granuloma ... Risks include exposure to swimming pools, salt water aquariums, or ocean fish. ... Wash hands and arms thoroughly after cleaning aquariums. Or, wear rubber gloves when cleaning.

  13. Differential activation of the human farnesoid X receptor depends on the pattern of expressed isoforms and the bile acid pool composition.

    PubMed

    Vaquero, Javier; Monte, Maria J; Dominguez, Mercedes; Muntané, Jordi; Marin, Jose J G

    2013-10-01

    The farnesoid X receptor (FXR) is a key sensor in bile acid homeostasis. Although four human FXR isoforms have been identified, the physiological role of this diversity is poorly understood. Here we investigated their subcellular localization, agonist sensitivity and response of target genes. Measurement of mRNA revealed that liver predominantly expressed FXRα1(+/-), whereas FXRα2(+/-) were the most abundant isoforms in kidney and intestine. In all cases, the proportion of FXRα(1/2)(+) and FXRα(1/2)(-) isoforms, i.e., with and without a 12bp insert, respectively, was approximately 50%. When FXR was expressed in liver and intestinal cells the magnitude of the response to GW4064 and bile acids differs among FXR isoforms. In both cell types the strongest response was that of FXRα1(-). Different efficacy of bile acids species to activate FXR was found. The four FXR isoforms shared the order of sensitivity to bile acids species. When in FXR-deficient cells FXR was transfected, unconjugated, but not taurine- and glycine-amidated bile acids, were able to activate FXR. In contrast, human hepatocytes and cell lines showing an endogenous expression of FXR were sensitive to both unconjugated and conjugated bile acids. This suggests that to activate FXR conjugated, but not unconjugated, bile acids require additional component(s) of the intracellular machinery not related with uptake processes, which are missing in some tumor cells. In conclusion, cell-specific pattern of FXR isoforms determine the overall tissue sensitivity to FXR agonists and may be involved in the differential response of FXR target genes to FXR activation.

  14. THE EFFECT OF MOLECULAR SIZE ON HUMIC ACID ASSOCIATIONS (R822832)

    EPA Science Inventory

    Abstract

    Aqueous solutions of two humic acids were subjected to UV photolysis, resulting in chain scission of the solute. The molecular fragments were found to have diminished detergent properties, indicated by a reduced tendency to associate with small hydrophobic spe...

  15. Unravelling the properties of supported copper oxide: can the particle size induce acidic behaviour?

    PubMed

    Zaccheria, Federica; Scotti, Nicola; Marelli, Marcello; Psaro, Rinaldo; Ravasio, Nicoletta

    2013-02-01

    There is a renewed interest in designing solid acid catalysts particularly due to the significance of Lewis acid catalyzed processes such as Friedel-Crafts acylation and alkylation and cellulose hydrolysis for the development of sustainable chemistry. This paper reports a new focus point on the properties of supported CuO on silica, a material that up to now has been considered only as the precursor of an effective hydrogenation catalyst. Thus, it deals with a re-interpretation of some of our results with supported copper oxide aimed to unveil the root of acidic activity exhibited by this material, e.g. in alcoholysis reactions. Several techniques were used to highlight the very high dispersion of the oxide phase on the support allowing us to ascribe the acidic behavior to coordinative unsaturation of the very small CuO particles. In turn this unsaturation makes the CuO particles prone to coordinate surrounding molecules present in the reaction mixture and to exchange them according to their nucleophilicity. PMID:23207422

  16. The hydrology of natural and artificial bog pools

    NASA Astrophysics Data System (ADS)

    Holden, Joseph; Turner, Ed; McKenzie, Rebecca; Baird, Andy; Billett, Mike; Chapman, Pippa; Dinsmore, Kerry; Dooling, Gemma

    2016-04-01

    Twelve bog pools were monitored over a 3.5-year period (2012-2015) in the Cross Lochs blanket peatland in the Flow Country of northern Scotland. Six pools were located in a natural pool complex while the other six were in an adjacent area where the peat had been ditched in the 1970s. The ditches had been subsequently dammed with peat in 2002 resulting in dozens of artificial pools along each ditch, with one pool upslope of each dam. The natural pools ranged in area from 15 m2 to 850 m2, while the artificial pools are a more uniform size at c.3 - 4 m2. Following a dry first summer, water levels in the 12 pools were lower throughout the subsequent winter and spring than they were in proceeding years showing strong inter-annual variability in pool levels even for winter months. Over the three year study, water level fluctuations in the natural pools were very different to those in the artificial pools. The natural pools showed subdued responses to rainfall and, after rainfall, slow falls in water level dominated by evaporation; the hydraulic conductivity of the peat was very low at depths of 30 and 50 cm below the peat surface around the pools (median values of 2.49 × 10-5 and 1.09 × 10-5 cm s-1 respectively). The artificial pools had much larger monthly interquartile ranges of water levels and a greater rise and fall of pool water level in response to each individual rainfall event compared with the natural pools. Thus the biogeochemistry and carbon cycling processes that occur within the natural pools is not likely to be replicated in the artificial pools as their hydrological behaviour is quite different. Slope position was a factor in terms of hydrological response of pools with those further downslope having higher relative water levels for longer periods of time compared to upslope pools. Thus we anticipate that local biogeochemical processes in and around bog pools may be impacted by slope position and by whether they are natural pools or artificial pools

  17. Size influences the cytotoxicity of poly (lactic-co-glycolic acid) (PLGA) and titanium dioxide (TiO(2)) nanoparticles.

    PubMed

    Xiong, Sijing; George, Saji; Yu, Haiyang; Damoiseaux, Robert; France, Bryan; Ng, Kee Woei; Loo, Joachim Say-Chye

    2013-06-01

    The aim of this study is to uncover the size influence of poly (lactic-co-glycolic acid) (PLGA) and titanium dioxide (TiO(2)) nanoparticles on their potential cytotoxicity. PLGA and TiO(2) nanoparticles of three different sizes were thoroughly characterized before in vitro cytotoxic tests which included viability, generation of reactive oxygen species (ROS), mitochondrial depolarization, integrity of plasma membrane, intracellular calcium influx and cytokine release. Size-dependent cytotoxic effect was observed in both RAW264.7 cells and BEAS-2B cells after cells were incubated with PLGA or TiO(2) nanoparticles for 24 h. Although PLGA nanoparticles did not trigger significantly lethal toxicity up to a concentration of 300 μg/ml, the TNF-α release after the stimulation of PLGA nanoparticles should not be ignored especially in clinical applications. Relatively more toxic TiO(2) nanoparticles triggered cell death, ROS generation, mitochondrial depolarization, plasma membrane damage, intracellular calcium concentration increase and size-dependent TNF-α release, especially at a concentration higher than 100 μg/ml. These cytotoxic effects could be due to the size-dependent interaction between nanoparticles and biomolecules, as smaller particles tend to adsorb more biomolecules. In summary, we demonstrated that the ability of protein adsorption could be an important paradigm to predict the in vitro cytotoxicity of nanoparticles, especially for low toxic nanomaterials such as PLGA and TiO(2) nanoparticles. PMID:22983807

  18. How to map your industry's profit pool.

    PubMed

    Gadiesh, O; Gilbert, J L

    1998-01-01

    Many managers chart strategy without a full understanding of the sources and distribution of profits in their industry. Sometimes they focus their sights on revenues instead of profits, mistakenly assuming that revenue growth will eventually translate into profit growth. In other cases, they simply lack the data or the analytical tools required to isolate and measure variations in profitability. In this Manager's Tool Kit, the authors present a way to think clearly about where the money's being made in any industry. They describe a framework for analyzing how profits are distributed among the activities that form an industry's value chain. Such an analysis can provide a company's managers with a rich understanding of their industry's profit structure--what the authors call its profit pool--enabling them to identify which activities are generating disproportionately large or small shares of profits. Even more important, a profit-pool map opens a window onto the underlying structure of the industry, helping managers see the various forces that are determining the distribution of profits. As such, a profit-pool map provides a solid basis for strategic thinking. Mapping a profit pool involves four steps: defining the boundaries of the pool, estimating the pool's overall size, estimating the size of each value-chain activity in the pool, and checking and reconciling the calculations. The authors briefly describe each step and then apply the process by providing a detailed example of a hypothetical retail bank. They conclude by looking at ways of organizing the data in chart form as a first step toward plotting a profit-pool strategy.

  19. Performance Study of Swimming Pool Heaters

    SciTech Connect

    McDonald, R.J.

    2009-01-01

    The objective of this report is to perform a controlled laboratory study on the efficiency and emissions of swimming pool heaters based on a limited field investigation into the range of expected variations in operational parameters. Swimming pool heater sales trends have indicated a significant decline in the number of conventional natural gas-fired swimming pool heaters (NGPH). On Long Island the decline has been quite sharp, on the order of 50%, in new installations since 2001. The major portion of the decline has been offset by a significant increase in the sales of electric powered heat pump pool heaters (HPPH) that have been gaining market favor. National Grid contracted with Brookhaven National Laboratory (BNL) to measure performance factors in order to compare the relative energy, environmental and economic consequences of using one technology versus the other. A field study was deemed inappropriate because of the wide range of differences in actual load variations (pool size), geographic orientations, ground plantings and shading variations, number of hours of use, seasonal use variations, occupancy patterns, hour of the day use patterns, temperature selection, etc. A decision was made to perform a controlled laboratory study based on a limited field investigation into the range of expected operational variations in parameters. Critical to this are the frequency of use, temperature selection, and sizing of the heater to the associated pool heating loads. This would be accomplished by installing a limited amount of relatively simple compact field data acquisition units on selected pool installations. This data included gas usage when available and alternately heater power or gas consumption rates were inferred from the manufacturer's specifications when direct metering was not available in the field. Figure 1 illustrates a typical pool heater installation layout.

  20. To pool or not to pool

    SciTech Connect

    Powell, J.

    1998-07-01

    In world electricity markets, third party access to transmission and distribution networks on non-discriminatory terms is available to generators and retail suppliers. Some market participants may believe that they are able to negotiate better terms and more market share through bilateral contracts than they would be able to obtain in a pool. Hence such companies will either argue against the development of a pool or seek to make membership of it optional. These companies are therefore seeking to ensure their continued ability to exercise their market power. Inevitably, those companies who would suffer in this form of market will advocate a more transparent arrangement where the market power of other organizations is curbed. The physical nature of the country and plant is also an important factor. Hydro-electric plant can, within water limitations, react very quickly to changing demand. These plant do not therefore require elaborate operating schedules hence market prices can be set ignoring physical plant characteristics. The ability of fossil fuel plant to respond is highly dependent on the operating condition of the plant. These generators need to plan their operations well in advance hence prices cannot be set in complete disregard of the generating plants' ability to meet the resulting schedule. The development of competitive markets is not, however, solely driven by commercial issues. Political and economic considerations such as stranded assets and the protection of indigenous industries, such as coal mines, can greatly influence the nature of the markets. Most countries have accepted the wisdom of having some form of pool. The choice of market mechanism will therefore be driven by: Physical constraints of the country infrastructure and plant; Market power of participants; and Political pressures on the Government. Of these factors political pressures tend to carry the greatest influence.

  1. The Transportable Auxin Pool 1

    PubMed Central

    de la Fuente, R. K.; Leopold, A. C.

    1970-01-01

    Evidences from experiments with stem sections of sunflower seedlings suggest that the transport of auxin may be limited by a restricted pool size of transportable auxin and restrictions in the availability of transport sites. A steady state of transport is observed over a range of lengths of stem sections, and over a wide range of auxin contents. The capacity of the sections to transport a pulse of auxin declines with aging after cutting, 50% decline occurring at about 10+ hours; the transportability of a pulse of auxin declines rapidly after the completion of uptake, 50% decline occurring at about 1 hour. A chase treatment with unlabeled auxin does not alter transport, but a pretreatment with auxin depressed subsequent transport for about 1 hour. In depleted tissues such pretreatment is not inhibitory but rather is promotive of transport. The interpretation offered is that transport is limited by the pool size and transport sites, and roles for these factors are suggested in relation to the auxin transport gradient and the tropistic responses. PMID:16657273

  2. Amino acid Alphabet Size in Protein Evolution Experiments: Better to Search a Small library Thoroughly or a Large Library Sparsely?

    PubMed Central

    Muñoz, Enrique

    2015-01-01

    We compare the results obtained from searching a smaller library thoroughly versus searching a more diverse, larger library sparsely. We study protein evolution with reduced amino acid alphabets, by simulating directed evolution experiments at three different alphabet sizes: 20, 5 and 2. We employ a physical model for evolution, the generalized NK model, that has proved successful in modeling protein evolution, antibody evolution, and T cell selection. We find that antibodies with higher affinity are found by searching a library with a larger alphabet sparsely than by searching a smaller library thoroughly, even with well-designed reduced libraries. We find ranked amino acid usage frequencies in agreement with observations of the CDR-H3 variable region of human antibodies. PMID:18375453

  3. Glycine intake decreases plasma free fatty acids, adipose cell size, and blood pressure in sucrose-fed rats.

    PubMed

    El Hafidi, Mohammed; Pérez, Israel; Zamora, Jose; Soto, Virgilia; Carvajal-Sandoval, Guillermo; Baños, Guadalupe

    2004-12-01

    The study investigated the mechanism by which glycine protects against increased circulating nonesterified fatty acids (NEFA), fat cell size, intra-abdominal fat accumulation, and blood pressure (BP) induced in male Wistar rats by sucrose ingestion. The addition of 1% glycine to the drinking water containing 30% sucrose, for 4 wk, markedly reduced high BP in sucrose-fed rats (SFR) (122.3 +/- 5.6 vs. 147.6 +/- 5.4 mmHg in SFR without glycine, P < 0.001). Decreases in plasma triglyceride (TG) levels (0.9 +/- 0.3 vs. 1.4 +/- 0.3 mM, P < 0.001), intra-abdominal fat (6.8 +/- 2.16 vs. 14.8 +/- 4.0 g, P < 0.01), and adipose cell size were observed in SFR treated with glycine compared with SFR without treatment. Total NEFA concentration in the plasma of SFR was significantly decreased by glycine intake (0.64 +/- 0.08 vs. 1.11 +/- 0.09 mM in SFR without glycine, P < 0.001). In control animals, glycine decreased glucose, TGs, and total NEFA but without reaching significance. In SFR treated with glycine, mitochondrial respiration, as an indicator of the rate of fat oxidation, showed an increase in the state IV oxidation rate of the beta-oxidation substrates octanoic acid and palmitoyl carnitine. This suggests an enhancement of hepatic fatty acid metabolism, i.e., in their transport, activation, or beta-oxidation. These findings imply that the protection by glycine against elevated BP might be attributed to its effect in increasing fatty acid oxidation, reducing intra-abdominal fat accumulation and circulating NEFA, which have been proposed as links between obesity and hypertension.

  4. Vernal Pool Lessons and Activities.

    ERIC Educational Resources Information Center

    Childs, Nancy; Colburn, Betsy

    This curriculum guide accompanies Certified: A Citizen's Step-by-Step Guide to Protecting Vernal Pools which is designed to train volunteers in the process of identifying vernal pool habitat so that as many of these pools as possible can be certified by the Massachusetts Natural Heritage and Endangered Species Program. Vernal pools are a kind of…

  5. Investment Policies and Concepts for Pools.

    ERIC Educational Resources Information Center

    Ellis, Robert L.

    1973-01-01

    Investment and endowment policies for educational institutions are shown to be greatly influenced by the size of the endowment and of the school budget. Administration of pooled funds is discussed with particular reference to procedures at Smith College. Establishment of an independent investment committee, separate from the finance committee, is…

  6. Quantifying protein synthesis and degradation in Arabidopsis by dynamic 13CO2 labeling and analysis of enrichment in individual amino acids in their free pools and in protein.

    PubMed

    Ishihara, Hirofumi; Obata, Toshihiro; Sulpice, Ronan; Fernie, Alisdair R; Stitt, Mark

    2015-05-01

    Protein synthesis and degradation represent substantial costs during plant growth. To obtain a quantitative measure of the rate of protein synthesis and degradation, we supplied (13)CO2 to intact Arabidopsis (Arabidopsis thaliana) Columbia-0 plants and analyzed enrichment in free amino acids and in amino acid residues in protein during a 24-h pulse and 4-d chase. While many free amino acids labeled slowly and incompletely, alanine showed a rapid rise in enrichment in the pulse and a decrease in the chase. Enrichment in free alanine was used to correct enrichment in alanine residues in protein and calculate the rate of protein synthesis. The latter was compared with the relative growth rate to estimate the rate of protein degradation. The relative growth rate was estimated from sequential determination of fresh weight, sequential images of rosette area, and labeling of glucose in the cell wall. In an 8-h photoperiod, protein synthesis and cell wall synthesis were 3-fold faster in the day than at night, protein degradation was slow (3%-4% d(-1)), and flux to growth and degradation resulted in a protein half-life of 3.5 d. In the starchless phosphoglucomutase mutant at night, protein synthesis was further decreased and protein degradation increased, while cell wall synthesis was totally inhibited, quantitatively accounting for the inhibition of growth in this mutant. We also investigated the rates of protein synthesis and degradation during leaf development, during growth at high temperature, and compared synthesis rates of Rubisco large and small subunits of in the light and dark. PMID:25810096

  7. Quantifying protein synthesis and degradation in Arabidopsis by dynamic 13CO2 labeling and analysis of enrichment in individual amino acids in their free pools and in protein.

    PubMed

    Ishihara, Hirofumi; Obata, Toshihiro; Sulpice, Ronan; Fernie, Alisdair R; Stitt, Mark

    2015-05-01

    Protein synthesis and degradation represent substantial costs during plant growth. To obtain a quantitative measure of the rate of protein synthesis and degradation, we supplied (13)CO2 to intact Arabidopsis (Arabidopsis thaliana) Columbia-0 plants and analyzed enrichment in free amino acids and in amino acid residues in protein during a 24-h pulse and 4-d chase. While many free amino acids labeled slowly and incompletely, alanine showed a rapid rise in enrichment in the pulse and a decrease in the chase. Enrichment in free alanine was used to correct enrichment in alanine residues in protein and calculate the rate of protein synthesis. The latter was compared with the relative growth rate to estimate the rate of protein degradation. The relative growth rate was estimated from sequential determination of fresh weight, sequential images of rosette area, and labeling of glucose in the cell wall. In an 8-h photoperiod, protein synthesis and cell wall synthesis were 3-fold faster in the day than at night, protein degradation was slow (3%-4% d(-1)), and flux to growth and degradation resulted in a protein half-life of 3.5 d. In the starchless phosphoglucomutase mutant at night, protein synthesis was further decreased and protein degradation increased, while cell wall synthesis was totally inhibited, quantitatively accounting for the inhibition of growth in this mutant. We also investigated the rates of protein synthesis and degradation during leaf development, during growth at high temperature, and compared synthesis rates of Rubisco large and small subunits of in the light and dark.

  8. An introduction to mid-Atlantic seasonal pools

    USGS Publications Warehouse

    Brown, L.J.; Jung, R.E.

    2005-01-01

    Seasonal pools, also known as vernal ponds, provide important ecological services to the mid-Atlantic region. This publication serves as an introduction to seasonal pool ecology and management; it also provides tools for exploring seasonal pools, including a full-color field guide to wildlife. Seasonal pools are defined as having four distinctive features: surface water isolation, periodic drying, small size and shallow depth, and support of a characteristic biological community. Seasonal pools experience regular drying that excludes populations of predatory fish. Thus, pools in the mid-Atlantic region provide critical breeding habitat for amphibian and invertebrate species (e.g., spotted salamander (Ambystoma maculatum), wood frog (Rana sylvatica), and fairy shrimp (Order Anostraca)) that would be at increased risk of predation in more permanent waters. The distinctive features of seasonal pools also make them vulnerable to human disturbance. In the mid-Atlantic region, land-use changes pose the greatest challenges to seasonal pool conservation. Seasonal pools are threatened by direct loss (e.g., filling or draining of the pool) as well as by destruction and fragmentation of adjoining terrestrial habitat. Many of the species that depend on seasonal pools for breeding spend the majority of their lives in the surrounding lands that extend a radius of 1000 feet or more from the pools; these vital habitats are being transected by roads and converted to other land uses. Other threats to seasonal pools include biological introductions and removals, mosquito control practices, amphibian diseases, atmospheric deposition, and climate change. The authors recommend a three-pronged strategy for seasonal pool conservation and management in the mid-Atlantic region: education and research, inventory and monitoring of seasonal pools, and landscape-level planning and management.

  9. Combined walking exercise and alkali therapy in patients with CKD4-5 regulates intramuscular free amino acid pools and ubiquitin E3 ligase expression.

    PubMed

    Watson, Emma L; Kosmadakis, George C; Smith, Alice C; Viana, Joao L; Brown, Jeremy R; Molyneux, Karen; Pawluczyk, Izabella Z A; Mulheran, Michael; Bishop, Nicolette C; Shirreffs, Susan; Maughan, Ronald J; Owen, Paul J; John, Stephen G; McIntyre, Christopher W; Feehally, John; Bevington, Alan

    2013-08-01

    Muscle-wasting in chronic kidney disease (CKD) arises from several factors including sedentary behaviour and metabolic acidosis. Exercise is potentially beneficial but might worsen acidosis through exercise-induced lactic acidosis. We studied the chronic effects of exercise in CKD stage 4-5 patients (brisk walking, 30 min, 5 times/week), and non-exercising controls; each group receiving standard oral bicarbonate (STD), or additional bicarbonate (XS) (Total n = 26; Exercising + STD n = 9; Exercising +XS n = 6; Control + STD n = 8; Control + XS n = 3). Blood and vastus lateralis biopsies were drawn at baseline and 6 months. The rise in blood lactate in submaximal treadmill tests was suppressed in the Exercising + XS group. After 6 months, intramuscular free amino acids (including the branched chain amino acids) in the Exercising + STD group showed a striking chronic depletion. This did not occur in the Exercising + XS group. The effect in Exercising + XS patients was accompanied by reduced transcription of ubiquitin E3-ligase MuRF1 which activates proteolysis via the ubiquitin-proteasome pathway. Other anabolic indicators (Akt activation and suppression of the 14 kDa actin catabolic marker) were unaffected in Exercising + XS patients. Possibly because of this, overall suppression of myofibrillar proteolysis (3-methylhistidine output) was not observed. It is suggested that alkali effects in exercisers arose by countering exercise-induced acidosis. Whether further anabolic effects are attainable on combining alkali with enhanced exercise (e.g. resistance exercise) merits further investigation. PMID:23591985

  10. Swimming pool cleaner poisoning

    MedlinePlus

    ... or breathes in its fumes. These cleaners contain chlorine and acids. Chlorine is more likely than the acids to cause ... are: Bromine Calcium chloride Calcium hypochlorite Chelated copper Chlorine Soda ash Sodium bicarbonate Various mild acids

  11. Preharvest application of oxalic acid increased fruit size, bioactive compounds, and antioxidant capacity in sweet cherry cultivars (Prunus avium L.).

    PubMed

    Martínez-Esplá, Alejandra; Zapata, Pedro Javier; Valero, Daniel; García-Viguera, Cristina; Castillo, Salvador; Serrano, María

    2014-04-16

    Trees of 'Sweet Heart' and 'Sweet Late' sweet cherry cultivars (Prunus avium L.) were treated with oxalic acid (OA) at 0.5, 1.0, and 2.0 mM at 98, 112, and 126 days after full blossom. Results showed that all treatments increased fruit size at harvest, manifested by higher fruit volume and weight in cherries from treated trees than from controls, the higher effect being found with 2.0 mM OA (18 and 30% higher weight for 'Sweet Heart' and 'Sweet Late', respectively). Other quality parameters, such as color and firmness, were also increased by OA treatments, although no significant differences were found in total soluble solids or total acidity, showing that OA treatments did not affect the on-tree ripening process of sweet cherry. However, the increases in total anthocyanins, total phenolics, and antioxidant activity associated with the ripening process were higher in treated than in control cherries, leading to fruit with high bioactive compounds and antioxidant potential at commercial harvest (≅45% more anthocyanins and ≅20% more total phenolics). In addition, individual anthocyanins, flavonols, and chlorogenic acid derivatives were also increased by OA treatment. Thus, OA preharvest treatments could be an efficient and natural way to increase the quality and functional properties of sweet cherries. PMID:24684635

  12. Thread Pool Interface (TPI)

    2008-04-01

    Thread Pool Interface (TpI) provides a simple interface for running functions written in C or C++ in a thread-parallel mode. Application or library codes may need to perform operations thread-parallel on machines with multicore processors. the TPI library provides a simple mechanism for managing thread activation, deactivation, and thread-parallel execution of application-provided subprograms.

  13. The Future of Pooling.

    ERIC Educational Resources Information Center

    Young, Peter C.; Fone, Martin

    1997-01-01

    Discusses seven propositions underlying the strategies that insurance pools can, will, and must pursue: (1) risk management versus risk financing; (2) elimination of windfall advantages; (3) the maintenance of market-dominant status; (4) cost leadership; (5) client focus; (6) innovation and diversification; and (7) leadership challenges. A sidebar…

  14. Channel Size Conversion of Phi29 DNA-Packaging Nanomotor for Discrimination of Single- and Double-Stranded Nucleic Acids

    PubMed Central

    Geng, Jia; Wang, Shaoying; Fang, Huaming; Guo, Peixuan

    2013-01-01

    Nanopores have been utilized to detect the conformation and dynamics of polymers, including DNA and RNA. Biological pores are extremely reproducible at the atomic level with uniform channel sizes. The channel of the bacterial virus phi29 DNA packaging motor is a natural conduit for the transportation of double-stranded DNA (dsDNA), and has the largest diameter among the well-studied biological channels. The larger channel facilitates translocation of dsDNA, and offers more space for further channel modification and conjugation. Interestingly, the relatively large wild type channel, which translocates dsDNA, cannot detect single-stranded nucleic acids (ssDNA or ssRNA) under the current experimental conditions. Herein, we reengineered this motor channel by removing the internal loop segment of the channel. The modification resulted in two classes of channels. One class was the same size as the wild type channel, while the other class had a cross-sectional area about 60% of the wild type. This smaller channel was able to detect the real-time translocation of single stranded nucleic acids at single-molecule level. While the wild type connector exhibited a one-way traffic property with respect to dsDNA translocation, the loop deleted connector was able to translocate ssDNA and ssRNA with equal competencies from both termini. This finding of size alterations in reengineered motor channels expands the potential application of the phi29 DNA packaging motor in nanomedicine, nanobiotechnology, and high-throughput single pore DNA sequencing. PMID:23488809

  15. Steam-explosion pretreatment of wood: effect of chip size, acid, moisture content and pressure drop

    SciTech Connect

    Brownell, H.H.; Yu, E.K.C.; Saddler, J.N.

    1986-06-01

    Material balances for pentosan, lignin, and hexosan, during steam-explosion pretreatment of aspenwood, showed almost quantitative recovery of cellulose in the water-insoluble fraction. Dilute acid impregnation resulted in more selective hydrolysis of pentosan relative to undesirable pyrolysis, and gave a more accessible substrate for enzymatic hydrolysis. Thermocouple probes, located inside simulated aspenwood chips heated in 240 degrees C-saturated steam, showed rapid heating of air-dry wood, whereas green or impregnated wood heated slowly. Small chips, 3.2 mm in the fiber direction, whether green or air dry gave approximately equal rates of pentosan destruction and solubilization, and similar yields of glucose and of total reducing sugars on enzmatic hydrolysis with Trichoderma harzianum. Partial pyrolysis, destroying one-third of the pentosan of aspenwood at atmospheric pressure by dry steam at 276 degrees C, gave little increase in yield of reducing sugars on enzymatic hydrolysis. Treatment with saturated steam at 240 degrees C gave essentially the same yields of butanediol and ethanol on fermentation with Klebsiella pneumoniae, whether or not 80% of the steam was bled off before explosion and even if the chips remained intact, showing that explosion was unnecessary. 17 references.

  16. DROWNING IN DISINFECTION BY-PRODUCTS? ASSESSING SWIMMING POOL WATER

    EPA Science Inventory

    The development of treated water for swimming pools has made swimming a year round activity, widely enjoyed for leisure as well as exercise. Swimming pools can be found in different kinds and sizes in public areas, hotels and spas, or at private homes. In Germany ~250-300 million...

  17. [Is Dutch swimming pool water erosive?].

    PubMed

    Lokin, P A; Huysmans, M C

    2004-01-01

    Etiological factors in the development of dental erosion are usually listed as dietary acids, for instance in soft drinks and fruit juices, and intrinsic acid exposure due to gastro-intestinal disease or frequent vomiting. Quite often the list of causes in reviews and textbooks also includes frequent swimming. This paper evaluates the evidence behind this erosion etiology. The main disinfection techniques using gas chlorination and sodium hypochlorite are described, and their relative risk for development of low pH water is discussed. In the Netherlands only the relatively safe sodium hypochlorite method is used, and the quality of the water in public swimming pools is monitored monthly by independent test laboratories. Data for 2001 from such a test laboratory show that the percentage of low-pH results is very low (0.14%). It is concluded that the risk of dental erosion from frequent swimming in acidic pool water is probably negligible in the Netherlands.

  18. Stable isotope labeling, in vivo, of D- and L-tryptophan pools in lemna gibba and the low incorporation of label into indole-3-acetic acid

    SciTech Connect

    Baldi, B.G. ); Maher, B.R. ); Slovin, J.P.; Cohen, J.D. Univ. of Maryland, College Park )

    1991-04-01

    The authors present evidence that the role of tryptophan and other potential intermediates in the pathways that could lead to indole derivatives needs to be reexamined. Two lines of Lemna gibba were tested for uptake of ({sup 15}N-indole)-labeled tryptophan isomers and incorporation of that label into free indole-3-acetic acid (IAA). Both lines required levels of L-({sup 15}N)tryptophan 2 to 3 orders of magnitude over endogenous levels in order to obtain measurable incorporation of label into IAA. Labeled L-tryptophan was extractable from plant tissue after feeding and showed no measurable isomerization into D-tryptophan. D-({sup 15}N)trytophan supplied to Lemna at rates of approximately 400 times excess of endogenous D-tryptophan levels (to yield an isotopic enrichment equal to that which allowed detection of the incorporation of L-tryptophan into IAA), did not result in measurable incorporation of label into free IAA. These results demonstrate that L-tryptophan is a more direct precursor to IAA than the D isomer and suggest (a) that the availability of tryptophan in vivo is not a limiting factor in the biosynthesis of IAA, thus implying that other regulatory mechanisms are in operation and (b) that L-tryptophan also may not be a primary precursor to IAA in plants.

  19. The Kallisti Limnes, carbon dioxide-accumulating subsea pools

    NASA Astrophysics Data System (ADS)

    2015-07-01

    Natural CO2 releases from shallow marine hydrothermal vents are assumed to mix into the water column, and not accumulate into stratified seafloor pools. We present newly discovered shallow subsea pools located within the Santorini volcanic caldera of the Southern Aegean Sea, Greece, that accumulate CO2 emissions from geologic reservoirs. This type of hydrothermal seafloor pool, containing highly concentrated CO2, provides direct evidence of shallow benthic CO2 accumulations originating from sub-seafloor releases. Samples taken from within these acidic pools are devoid of calcifying organisms, and channel structures among the pools indicate gravity driven flow, suggesting that seafloor release of CO2 at this site may preferentially impact benthic ecosystems. These naturally occurring seafloor pools may provide a diagnostic indicator of incipient volcanic activity and can serve as an analog for studying CO2 leakage and benthic accumulations from subsea carbon capture and storage sites.

  20. The Kallisti Limnes, carbon dioxide-accumulating subsea pools.

    PubMed

    Camilli, Richard; Nomikou, Paraskevi; Escartín, Javier; Ridao, Pere; Mallios, Angelos; Kilias, Stephanos P; Argyraki, Ariadne

    2015-07-16

    Natural CO2 releases from shallow marine hydrothermal vents are assumed to mix into the water column, and not accumulate into stratified seafloor pools. We present newly discovered shallow subsea pools located within the Santorini volcanic caldera of the Southern Aegean Sea, Greece, that accumulate CO2 emissions from geologic reservoirs. This type of hydrothermal seafloor pool, containing highly concentrated CO2, provides direct evidence of shallow benthic CO2 accumulations originating from sub-seafloor releases. Samples taken from within these acidic pools are devoid of calcifying organisms, and channel structures among the pools indicate gravity driven flow, suggesting that seafloor release of CO2 at this site may preferentially impact benthic ecosystems. These naturally occurring seafloor pools may provide a diagnostic indicator of incipient volcanic activity and can serve as an analog for studying CO2 leakage and benthic accumulations from subsea carbon capture and storage sites.

  1. The Kallisti Limnes, carbon dioxide-accumulating subsea pools

    PubMed Central

    Camilli, Richard; Nomikou, Paraskevi; Escartín, Javier; Ridao, Pere; Mallios, Angelos; Kilias, Stephanos P.; Argyraki, Ariadne; Andreani, Muriel; Ballu, Valerie; Campos, Ricard; Deplus, Christine; Gabsi, Taoufic; Garcia, Rafael; Gracias, Nuno; Hurtós, Natàlia; Magí, Lluis; Mével, Catherine; Moreira, Manuel; Palomeras, Narcís; Pot, Olivier; Ribas, David; Ruzié, Lorraine; Sakellariou, Dimitris

    2015-01-01

    Natural CO2 releases from shallow marine hydrothermal vents are assumed to mix into the water column, and not accumulate into stratified seafloor pools. We present newly discovered shallow subsea pools located within the Santorini volcanic caldera of the Southern Aegean Sea, Greece, that accumulate CO2 emissions from geologic reservoirs. This type of hydrothermal seafloor pool, containing highly concentrated CO2, provides direct evidence of shallow benthic CO2 accumulations originating from sub-seafloor releases. Samples taken from within these acidic pools are devoid of calcifying organisms, and channel structures among the pools indicate gravity driven flow, suggesting that seafloor release of CO2 at this site may preferentially impact benthic ecosystems. These naturally occurring seafloor pools may provide a diagnostic indicator of incipient volcanic activity and can serve as an analog for studying CO2 leakage and benthic accumulations from subsea carbon capture and storage sites. PMID:26179858

  2. Simulation of energetic stability of facetted l-glutamic acid nanocrystalline clusters in relation to their polymorphic phase stability as a function of crystal size.

    PubMed

    Hammond, R B; Pencheva, K; Roberts, K J

    2005-10-27

    A molecular modeling approach is used to study the stability of different polymorphic forms of l-glutamic acid through building and optimizing molecular clusters of different sizes and shapes with the latter corresponding to the predicted crystal growth morphologies. The results reveal that the initially nucleating (according to Oswald rule) metastable (alpha) form is the more energetically stable form at small cluster sizes of ca. 200 molecular units, whereas the stable (beta) form is more stable when the cluster size is larger.

  3. Microwave selective heating for size effect of water droplet in W/O emulsion with sorbitan fatty acid monostearate surfactant

    NASA Astrophysics Data System (ADS)

    Sumi, Takuya; Horikoshi, Satoshi

    2015-09-01

    A stable water/oil (W/O) emulsion was prepared by adjustment with sorbitan fatty acid monoester surfactants. The prepared W/O emulsion was stable for 60 min in the atmosphere; however, the formation of non-uniform water droplets in the height of the emulsion in the quartz tube reactor were observed by the backscattering measurements with an infrared laser at 850 nm. The increase of temperature under microwave irradiation was influenced sensitively by the position of those water droplets. Those results were caused from the size and concentration of water droplets in the W/O emulsion. On the other hand, selective heating of the water droplets caused heating of the entire W/O emulsion, although the temperature difference between the water droplets and the oil phase was 20 °C.

  4. Genotype and fetal size affect maternal-fetal amino acid status and fetal endocrinology in Large White × Landrace and Meishan pigs.

    PubMed

    Ashworth, Cheryl J; Nwagwu, Margaret O; McArdle, Harry J

    2013-01-01

    This study compared maternal plasma amino acid concentrations, placental protein secretion in vitro and fetal body composition and plasma amino acid and hormone concentrations in feto-placental units from the smallest and a normally-sized fetus carried by Large White × Landrace or Meishan gilts on Day 100 of pregnancy. Compared with Large White × Landrace, Meishan placental tissue secreted more protein and Meishan fetuses contained relatively more fat and protein, but less moisture. Fetal plasma concentrations of insulin, triiodothryonine, thyroxine and insulin-like growth factor (IGF)-II were higher in Meishan than Large White × Landrace fetuses. In both breeds, fetal cortisol concentrations were inversely related to fetal size, whereas concentrations of IGF-I were higher in average-sized fetuses. Concentrations of 10 amino acids were higher in Large White × Landrace than Meishan gilts, while glutamine concentrations were higher in Meishan gilts. Concentrations of alanine, aspartic acid, glutamic acid and threonine were higher in Meishan than Large White × Landrace fetuses. Average-sized fetuses had higher concentrations of asparagine, leucine, lysine, phenylalanine, threonine, tyrosine and valine than the smallest fetus. This study revealed novel genotype and fetal size differences in porcine maternal-fetal amino acid status and fetal hormone and metabolite concentrations.

  5. Allergic to Pool Water

    PubMed Central

    2012-01-01

    To identify the allergy problem of a 36-year old swimming instructor, who experiences heavy itching and rashes whenever she comes in contact with pool water. Patch tests were performed with European standard series and materials from the work floor. A positive patch test to aluminum chloride and flocculant was observed. Occupational dermatitis is, based on a contact allergy to aluminum chloride in the flocculant. PMID:22993713

  6. Swimming Pools and Molluscum Contagiosum

    MedlinePlus

    ... Travelers' Health: Smallpox & Other Orthopoxvirus-Associated Infections Poxvirus Swimming Pools Recommend on Facebook Tweet Share Compartir The ... often ask if molluscum virus can spread in swimming pools. There is also concern that it can ...

  7. Habitat species pools for phylogenetic structure in microbes.

    PubMed

    Wang, Jianjun; Soininen, Janne; Shen, Ji

    2013-06-01

    The processes underlying the phylogenetic structure of the biotic communities are typically scale-dependent and thus often poorly resolved. Illustrated by the study of macroorganisms, it is suggested that the relative influence of ecological processes on the phylogenetic structure of the communities can be inferred by the geographical definition of the species pools. However, given the high dispersal ability of microbes, the spatial delineation of the species pool may not be that practical for microbial taxa. This idea is supported by the observational data on bacteria along an elevational gradient. Significant negative values of standardized effect size of the mean nearest taxon distance were consistently observed for different sized species pools considered. Reviewing the reports on microbial phylogenetic structure so far, we suggested that the 'habitat species pools' are perhaps more important for microbes than spatial delineated 'regional species pools'. PMID:23754726

  8. Quantifying solubility enhancement due to particle size reduction and crystal habit modification: case study of acetyl salicylic acid.

    PubMed

    Hammond, Robert B; Pencheva, Klimentina; Roberts, Kevin J; Auffret, Tony

    2007-08-01

    The poor solubility of potential drug molecules is a significant problem in the design of pharmaceutical formulations. It is well known, however, that the solubility of crystalline materials is enhanced when the particle size is reduced to submicron levels and this factor can be expected to enhance drug product bioavailability. Direct estimation of solubility enhancement, as calculated via the Gibbs-Thompson relationship, demands reasonably accurate values for the particle/solution interfacial tension and, in particular, its anisotropy with respect to the crystal product's habit and morphology. In this article, an improved, more molecule-centered, approach is presented towards the calculation of solubility enhancement factors in which molecular modeling techniques are applied, and the effects associated with both crystal habit modification and solvent choice are examined. A case study for facetted, acetyl salicylic acid (aspirin) crystals in equilibrium with saturated aqueous ethanol solution reveals that their solubility will be enhanced in the range (7-58%) for a crystal size of 0.02 microm, with significantly higher enhancement for crystal morphologies in which the hydrophobic crystal faces are more predominant than the hydrophilic faces and for solvents in which the solubility is smaller.

  9. Reversible phospholipid nanogels for deoxyribonucleic acid fragment size determinations up to 1500 base pairs and integrated sample stacking.

    PubMed

    Durney, Brandon C; Bachert, Beth A; Sloane, Hillary S; Lukomski, Slawomir; Landers, James P; Holland, Lisa A

    2015-06-23

    Phospholipid additives are a cost-effective medium to separate deoxyribonucleic acid (DNA) fragments and possess a thermally-responsive viscosity. This provides a mechanism to easily create and replace a highly viscous nanogel in a narrow bore capillary with only a 10°C change in temperature. Preparations composed of dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) self-assemble, forming structures such as nanodisks and wormlike micelles. Factors that influence the morphology of a particular DMPC-DHPC preparation include the concentration of lipid in solution, the temperature, and the ratio of DMPC and DHPC. It has previously been established that an aqueous solution containing 10% phospholipid with a ratio of [DMPC]/[DHPC]=2.5 separates DNA fragments with nearly single base resolution for DNA fragments up to 500 base pairs in length, but beyond this size the resolution decreases dramatically. A new DMPC-DHPC medium is developed to effectively separate and size DNA fragments up to 1500 base pairs by decreasing the total lipid concentration to 2.5%. A 2.5% phospholipid nanogel generates a resolution of 1% of the DNA fragment size up to 1500 base pairs. This increase in the upper size limit is accomplished using commercially available phospholipids at an even lower material cost than is achieved with the 10% preparation. The separation additive is used to evaluate size markers ranging between 200 and 1500 base pairs in order to distinguish invasive strains of Streptococcus pyogenes and Aspergillus species by harnessing differences in gene sequences of collagen-like proteins in these organisms. For the first time, a reversible stacking gel is integrated in a capillary sieving separation by utilizing the thermally-responsive viscosity of these self-assembled phospholipid preparations. A discontinuous matrix is created that is composed of a cartridge of highly viscous phospholipid assimilated into a separation matrix

  10. Shifts in the carbohydrate, polyol, and amino acid pools during rapid cold-hardening and diapause-associated cold-hardening in flesh flies (Sarcophaga crassipalpis): a metabolomic comparison.

    PubMed

    Michaud, M Robert; Denlinger, David L

    2007-10-01

    Flesh flies can enhance their cold hardiness by entering a photoperiod-induced pupal diapause or by a temperature-induced rapid cold-hardening process. To determine whether the same or different metabolites are involved in these two responses, derivatized polar extracts from flesh flies subjected to these treatments were examined using gas chromatography-mass spectrophotometry (GC-MS). This metabolomic approach demonstrated that levels of metabolites involved in glycolysis (glycerol, glucose, alanine, pyruvate) were elevated by both treatments. Metabolites elevated uniquely in response to rapid cold-hardening include glutamine, cystathionine, sorbitol, and urea while levels of beta-alanine, ornithine, trehalose, and mannose levels were reduced. Rapid cold-hardening also uniquely perturbed the urea cycle. In addition to the elevated metabolites shared with rapid cold-hardening, leucine concentrations were uniquely elevated during diapause while levels of a number of other amino acids were reduced. Pools of two aerobic metabolic intermediates, fumarate and citrate, were reduced during diapause, indicating a reduction of Krebs cycle activity. Principal component analysis demonstrated that rapid cold-hardening and diapause are metabolically distinct from their untreated, non-diapausing counterparts. We discuss the possible contribution of each altered metabolite in enhancing the overall cold hardiness of the organism, as well as the efficacy of GC-MS metabolomics for investigating insect physiological systems.

  11. Degradation and osteogenic potential of a novel poly(lactic acid)/nano-sized β-tricalcium phosphate scaffold

    PubMed Central

    Cao, Lu; Duan, Ping-Guo; Wang, Hui-Ren; Li, Xi-Lei; Yuan, Feng-Lai; Fan, Zhong-Yong; Li, Su-Ming; Dong, Jian

    2012-01-01

    The purpose of this study was to investigate the influence of nano-sized β-tricalcium phosphate (β-TCP) on the biological performance of poly (lactic acid) (PLA) composite scaffolds by using in vitro degradation and an in vivo model of heterotopic bone formation. Nano-sized β-TCP (nβ-TCP) was prepared with a wet grinding method from micro-sized β-TCP (mβ-TCP), and composite scaffolds containing 0, 10, 30, or 50 wt% nβ-TCP or 30 wt% mβ-TCP were generated using a freeze-drying method. Degradation was assessed by monitoring changes in microstructure, pH, weight, and compressive strength over a 26-week period of hydrolysis. Composite scaffolds were processed into blocks, and implanted into muscular pockets of rabbits after loading with recombinant human bone morphogenetic protein-2 (rhBMP-2). New bone formation was evaluated based on histological and immunohistochemical analysis 2, 4, and 8 weeks after implantation. The in vitro results indicated that the buffering effect of nβ-TCP was stronger than mβ-TCP, which was positively correlated with the content of nβ-TCP. The in vivo findings demonstrated that nβ-TCP enhanced the osteoconductivity of the scaffolds. Although composite scaffolds containing 30% nβ-TCP exhibited similar osteoconductivity to 50% nβ-TCP, they had better mechanical properties than the 50% nβ-TCP scaffolds. This study supports the potential application of a composite scaffold containing 30% nβ-TCP as a promising scaffold for bone regeneration. PMID:23226019

  12. Identification of disinfection by-products in freshwater and seawater swimming pools and evaluation of genotoxicity.

    PubMed

    Manasfi, Tarek; De Méo, Michel; Coulomb, Bruno; Di Giorgio, Carole; Boudenne, Jean-Luc

    2016-03-01

    Exposure to disinfection byproducts (DBPs) in swimming pools has been linked to adverse health effects. Numerous DBPs that occur in swimming pools are genotoxic and carcinogenic. This toxicity is of a greater concern in the case of brominated DBPs that have been shown to have substantially greater toxicities than their chlorinated analogs. In chlorinated seawater swimming pools, brominated DBPs are formed due to the high content of bromide. Nevertheless, very little data is reported about DBP occurrence and mutagenicity of water in these pools. In the present study, three seawater and one freshwater swimming pools located in Southeastern France were investigated to determine qualitatively and quantitatively their DBP contents. An evaluation of the genotoxic properties of water samples of the freshwater pool and a seawater pool was conducted through the Salmonella assay (Ames test). The predominant DBPs identified in the freshwater pool were chlorinated species and included trichloroacetic acid, chloral hydrate, dichloroacetonitrile, 1,1,1-trichloropropanone and chloroform. In the seawater pools, brominated DBPs were the predominant species and included dibromoacetic acid, bromoform and dibromoacetonitile. Bromal hydrate levels were also reported. In both types of pools, haloacetic acids were the most prevalent chemical class among the analyzed DBP classes. The distribution of other DBP classes varied depending on the type of pool. As to genotoxicity, the results of Ames test showed higher mutagenicity in the freshwater pool as a consequence of its considerably higher DBP contents in comparison to the tested seawater pool.

  13. Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates

    PubMed Central

    Surawathanawises, Krissada; Cheng, Xuanhong

    2014-01-01

    Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation. PMID:24535886

  14. Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates.

    PubMed

    Surawathanawises, Krissada; Cheng, Xuanhong

    2014-01-20

    Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation.

  15. A three-pool model dissecting readily releasable pool replenishment at the calyx of held.

    PubMed

    Guo, Jun; Ge, Jian-long; Hao, Mei; Sun, Zhi-cheng; Wu, Xin-sheng; Zhu, Jian-bing; Wang, Wei; Yao, Pan-tong; Lin, Wei; Xue, Lei

    2015-03-31

    Although vesicle replenishment is critical in maintaining exo-endocytosis recycling, the underlying mechanisms are not well understood. Previous studies have shown that both rapid and slow endocytosis recycle into a very large recycling pool instead of within the readily releasable pool (RRP), and the time course of RRP replenishment is slowed down by more intense stimulation. This finding contradicts the calcium/calmodulin-dependence of RRP replenishment. Here we address this issue and report a three-pool model for RRP replenishment at a central synapse. Both rapid and slow endocytosis provide vesicles to a large reserve pool (RP) ~42.3 times the RRP size. When moving from the RP to the RRP, vesicles entered an intermediate pool (IP) ~2.7 times the RRP size with slow RP-IP kinetics and fast IP-RRP kinetics, which was responsible for the well-established slow and rapid components of RRP replenishment. Depletion of the IP caused the slower RRP replenishment observed after intense stimulation. These results establish, for the first time, a realistic cycling model with all parameters measured, revealing the contribution of each cycling step in synaptic transmission. The results call for modification of the current view of the vesicle recycling steps and their roles.

  16. Item Pool Design for an Operational Variable-Length Computerized Adaptive Test

    ERIC Educational Resources Information Center

    He, Wei; Reckase, Mark D.

    2014-01-01

    For computerized adaptive tests (CATs) to work well, they must have an item pool with sufficient numbers of good quality items. Many researchers have pointed out that, in developing item pools for CATs, not only is the item pool size important but also the distribution of item parameters and practical considerations such as content distribution…

  17. Secondary pool boiling effects

    NASA Astrophysics Data System (ADS)

    Kruse, C.; Tsubaki, A.; Zuhlke, C.; Anderson, T.; Alexander, D.; Gogos, G.; Ndao, S.

    2016-02-01

    A pool boiling phenomenon referred to as secondary boiling effects is discussed. Based on the experimental trends, a mechanism is proposed that identifies the parameters that lead to this phenomenon. Secondary boiling effects refer to a distinct decrease in the wall superheat temperature near the critical heat flux due to a significant increase in the heat transfer coefficient. Recent pool boiling heat transfer experiments using femtosecond laser processed Inconel, stainless steel, and copper multiscale surfaces consistently displayed secondary boiling effects, which were found to be a result of both temperature drop along the microstructures and nucleation characteristic length scales. The temperature drop is a function of microstructure height and thermal conductivity. An increased microstructure height and a decreased thermal conductivity result in a significant temperature drop along the microstructures. This temperature drop becomes more pronounced at higher heat fluxes and along with the right nucleation characteristic length scales results in a change of the boiling dynamics. Nucleation spreads from the bottom of the microstructure valleys to the top of the microstructures, resulting in a decreased surface superheat with an increasing heat flux. This decrease in the wall superheat at higher heat fluxes is reflected by a "hook back" of the traditional boiling curve and is thus referred to as secondary boiling effects. In addition, a boiling hysteresis during increasing and decreasing heat flux develops due to the secondary boiling effects. This hysteresis further validates the existence of secondary boiling effects.

  18. Effect of Wheat Dietary Fiber Particle Size during Digestion In Vitro on Bile Acid, Faecal Bacteria and Short-Chain Fatty Acid Content.

    PubMed

    Dziedzic, Krzysztof; Szwengiel, Artur; Górecka, Danuta; Gujska, Elżbieta; Kaczkowska, Joanna; Drożdżyńska, Agnieszka; Walkowiak, Jarosław

    2016-06-01

    The influence of bile acid concentration on the growth of Bifidobacterium spp. and Lactobacillus spp. bacteria was demonstrated. Exposing these bacteria to the environment containing bile acid salts, and very poor in nutrients, leads to the disappearance of these microorganisms due to the toxic effect of bile acids. A multidimensional analysis of data in the form of principal component analysis indicated that lactic acid bacteria bind bile acids and show antagonistic effect on E. coli spp. bacteria. The growth in E. coli spp. population was accompanied by a decline in the population of Bifidobacterium spp. and Lactobacillus spp. with a simultaneous reduction in the concentration of bile acids. This is direct proof of acid binding ability of the tested lactic acid bacteria with respect to cholic acid, lithocholic acid and deoxycholic acid. This research demonstrated that the degree of fineness of wheat dietary fibre does not affect the sorption of bile acids and growth of some bacteria species; however, it has an impact on the profile of synthesized short-chained fatty acids. During the digestion of a very fine wheat fibre fraction (WF 90), an increase in the concentration of propionic and butyric acids, as compared with the wheat fiber fraction of larger particles - WF 500, was observed. Our study suggested that wheat fibre did not affect faecal bacteria growth, however, we observed binding of bile acids by Bifidobacterium spp. and Lactobacillus spp.

  19. Effect of Wheat Dietary Fiber Particle Size during Digestion In Vitro on Bile Acid, Faecal Bacteria and Short-Chain Fatty Acid Content.

    PubMed

    Dziedzic, Krzysztof; Szwengiel, Artur; Górecka, Danuta; Gujska, Elżbieta; Kaczkowska, Joanna; Drożdżyńska, Agnieszka; Walkowiak, Jarosław

    2016-06-01

    The influence of bile acid concentration on the growth of Bifidobacterium spp. and Lactobacillus spp. bacteria was demonstrated. Exposing these bacteria to the environment containing bile acid salts, and very poor in nutrients, leads to the disappearance of these microorganisms due to the toxic effect of bile acids. A multidimensional analysis of data in the form of principal component analysis indicated that lactic acid bacteria bind bile acids and show antagonistic effect on E. coli spp. bacteria. The growth in E. coli spp. population was accompanied by a decline in the population of Bifidobacterium spp. and Lactobacillus spp. with a simultaneous reduction in the concentration of bile acids. This is direct proof of acid binding ability of the tested lactic acid bacteria with respect to cholic acid, lithocholic acid and deoxycholic acid. This research demonstrated that the degree of fineness of wheat dietary fibre does not affect the sorption of bile acids and growth of some bacteria species; however, it has an impact on the profile of synthesized short-chained fatty acids. During the digestion of a very fine wheat fibre fraction (WF 90), an increase in the concentration of propionic and butyric acids, as compared with the wheat fiber fraction of larger particles - WF 500, was observed. Our study suggested that wheat fibre did not affect faecal bacteria growth, however, we observed binding of bile acids by Bifidobacterium spp. and Lactobacillus spp. PMID:26924312

  20. Europium(III) complexed by HPSEC size-fractions of a vertisol humic acid: Small differences evidenced by time-resolved luminescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Reiller, Pascal E.; Brevet, Julien; Nebbioso, Antonio; Piccolo, Alessandro

    2011-03-01

    The size fractionation of a humic acid (HA) by high performance size exclusion chromatography (HPSEC) was used as a proxy for the filtration effect during HA transport through a porous medium with minimum specific chemical interactions. The modification of the Eu(III)-HA complexes' formation with the different size-fractions, as compared to the bulk HA, was studied in time-resolved luminescence spectroscopy (TRLS). Clear modifications in Eu(III)-HA complexes' structures were shown and related to the molecular characteristics of the separated size-fractions. The properties of most of size-fractions did not induce a major alteration of the affinity towards Eu(III). Only the most hydrophilic fractions eluted in the tail of the chromatographic peak, representing about 11% of total fractions-weight, gave some significantly different parameters. Using a simplistic complexation model, it was found that the available complexation sites decreased with the size reduction of humic fractions.

  1. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems

    PubMed Central

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N.

    2016-01-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250–2000 μm) and fine sand (53–250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources. PMID:27555553

  2. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems

    NASA Astrophysics Data System (ADS)

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N.

    2016-08-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250–2000 μm) and fine sand (53–250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources.

  3. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems.

    PubMed

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N

    2016-01-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250-2000 μm) and fine sand (53-250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources.

  4. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems.

    PubMed

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N

    2016-01-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250-2000 μm) and fine sand (53-250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources. PMID:27555553

  5. Photocatalytic degradation of p-nitrophenol on nanometer size titanium dioxide surface modified with 5-sulfosalicylic acid.

    PubMed

    Li, Shun-xing; Zheng, Feng-ying; Liu, Xian-li; Wu, Feng; Deng, Nan-sheng; Yang, Jian-hong

    2005-10-01

    The surface of nanometer size TiO(2) was simply and fast modified by chemical adsorption in saturated solution of 5-sulfosalicylic acid. After surface modification, a stable, yellow surface complex was formed quickly, the wavelength response range of TiO(2) was expanded, it has obvious absorption in the region from 320 to 450 nm; the adsorption efficiency of p-nitrophenol (PNP) by TiO(2) was enhanced from 42% to 84%. The photocatalytic activity was tested on the degradation of PNP. The influences of catalyst and its dosage, pH value, and PNP concentration on the degradation were investigated. On optimal photodegradation conditions, including initial pH 4.0, PNP 5 mg l(-1), catalyst 100 mg, irradiation time 120 min with 160 W high-pressure mercury lamp, the degradation efficiency of PNP was increased from 40% to 88% after surface modification. Surface modification led not only to an increase in the light utilization, but also improved the surface coverage of PNP in comparison with the pure TiO(2). Both of these factors are crucial for the photocatalytic activity of heterogeneous photocatalysis, especially for photodegradation of benzenoid pollutants. PMID:16202814

  6. Biochemical distributions (amino acids, neutral sugars, and lignin phenols) among size-classes of modern marine sediments from the Washington coast

    NASA Astrophysics Data System (ADS)

    Keil, Richard G.; Tsamakis, Elizabeth; Giddings, J. Calvin; Hedges, John I.

    1998-04-01

    In order to examine relationships of organic matter source, composition, and diagenesis with particle size and mineralogy in modern marine depositional regimes, sediments from the continental shelf and slope along the Northwest Pacific rim (Washington coast, USA) were sorted into hydrodynamic size fractions (sand: >250, 63-250 μm; silt: 35-63, 17-35, 8-17, 3-8 μm; and clay-sized: 1-3, 0.5-1, <0.5 μm). The size fractions were then density fractionated to separate distinct organic debris from mineral-associated organic matter, and the various separates were analyzed for their amino acid, aldose, and lignin compositions. The composition of organic matter in the separates changes markedly as a function of particle size and density. Large compositional differences were observed between the clay-sized fractions (dominated mineralogically by smectites), the sand-sized mineral-associated isolates (quartz-rich), and floated coarse organic matter (dominated by vascular plant debris). Organic matter intimately associated with the clay-sized fractions shows the most extensive diagenetic alteration, as reflected in high abundances of nonprotein amino acids (especially β-alanine), elevated lignin phenol acid/aldehyde ratios, and high relative concentrations of the deoxyhexoses fucose and rhamnose. Organic matter in the silt fractions, though degraded, is not as diagenetically altered as in the clay fractions. Enrichment of pollen grains in the silt-size material is reflected by high cinnamic acid to ferulic acid lignin phenol ratios. The highest pollen biochemical signal is observed in the silt fractions of the deepest station (1835 m), where pollen abundances are also highest. Organic matter tightly bound in the silt and sand-sized fractions are enriched in aldoses and show indications of enhanced microbial biomass as reflected by high weight percentages of ribose. Distinct organic debris was composed of relatively unaltered vascular plant remains as reflected by high

  7. The purine efflux pump PbuE in Bacillus subtilis modulates expression of the PurR and G-box (XptR) regulons by adjusting the purine base pool size.

    PubMed

    Nygaard, Per; Saxild, Hans H

    2005-01-01

    In Bacillus subtilis, the expression of genes encoding enzymes and other proteins involved in purine de novo synthesis and salvage is affected by purine bases and phosphoribosylpyrophosphate (PRPP). The transcription of the genes belonging to the PurR regulon is negatively regulated by the PurR protein and PRPP. The expression of the genes belonging to the G-box (XptR) regulon, including the pbuE gene, is negatively regulated by a riboswitch-controlled transcription termination mechanism. The G-box regulon effector molecules are hypoxanthine and guanine. pbuE encodes a purine base efflux pump and is now recognized as belonging to a third purine regulon. The expression of the pbuE gene is positively regulated by a riboswitch that recognizes adenine. Here we show that the expression of pbuE'-lacZ transcriptional fusions are induced by adenine to the highest extent in mutants which do not express a functional PbuE pump. In a mutant defective in the metabolism of adenine, the ade apt mutant, we found a high intracellular level of adenine and constitutive high levels of PbuE. A growth test using a purine auxotroph provided further evidence for the role of PbuE in lowering the intracellular concentration of purine bases, including adenine. Purine analogs also affect the expression of pbuE, which might be of importance for the protection against toxic analogs. In a mutant that overexpresses PbuE, the expression of genes belonging to the PurR regulon was increased. Our findings provide further evidence for important functions of the PbuE protein, such as acting as a pump that lowers the purine base pool and affects the expression of the G-box and PurR regulons, including pbuE itself, and as a pump involved in protection against toxic purine base analogs.

  8. Bimodal size distributions of various organic acids and fatty acids in the marine atmosphere: Influence of anthropogenic aerosols, Asian dusts, and sea spray off the coast of East Asia

    NASA Astrophysics Data System (ADS)

    Mochida, Michihiro; Umemoto, Nobuhiko; Kawamura, Kimitaka; Lim, Ho-Jin; Turpin, Barbara J.

    2007-08-01

    Size-segregated (11 stages) marine aerosol samples were collected off the coast of East Asia during the ACE-Asia campaign in 2001 and were analyzed for homologous series of dicarboxylic acids (C2-C12), ω-oxocarboxylic acids (C2-C4), and n-fatty acids (C16-C30), as well as organic carbon (OC), elemental carbon, and major inorganic ions. Concentrations of OC and major diacids and oxoacids in continental polluted air masses showed predominantly submicron maxima. However, during dusty haze events, supermicron maxima were observed, suggesting a size shift due to the secondary accumulation of these components on dust as well as sea salt particles. Supermicron maxima were also found for palmitic acid (C16 fatty acid) and other lower-molecular-weight fatty acids (LFAs, C16-C19) that are emitted from a microlayer of the ocean surface. In contrast, higher-molecular-weight fatty acids (HFAs, C20-C30) were mainly detected in the submicron mode, presumably due to a substantial contribution of biomass burning aerosols. This study demonstrates a high-variability in the size distributions of organic components (i.e., between submicron and supermicron modes) in the coastal regions off East Asia. Such variations in the physical properties of the marine aerosols may be important in relation to their cloud-condensation-nuclei and light extinction activities.

  9. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. II. Formation and decomposition of thiosulfate and polythionate in Cinder Pool

    USGS Publications Warehouse

    Xu, Y.; Schoonen, M.A.A.; Nordstrom, D.K.; Cunningham, K.M.; Ball, J.W.

    2000-01-01

    Cinder Pool is an acid-sulfate-chloride boiling spring in Norris Geyser Basin, Yellowstone National Park. The pool is unique in that its surface is partially covered with mm-size, black, hollow sulfur spherules, while a layer of molten sulfur resides at the bottom of the pool (18 m depth). The sulfur speciation in the pool was determined on four different days over a period of two years. Samples were taken to evaluate changes with depth and to evaluate the importance of the sulfur spherules on sulfur redox chemistry. All analyses were conducted on site using a combination of ion chromatography and colorimetric techniques. Dissolved sulfide (H2S), thiosulfate (S2O32−), polythionates (SxO62−), and sulfate were detected. The polythionate concentration was highly variable in time and space. The highest concentrations were found in surficial samples taken from among the sulfur spherules. With depth, the polythionate concentrations dropped off. The maximum observed polythionate concentration was 8 μM. Thiosulfate was rather uniformly distributed throughout the pool and concentrations ranged from 35 to 45 μM. Total dissolved sulfide concentrations varied with time, concentrations ranged from 16 to 48 μM. Sulfate was relatively constant, with concentrations ranging from 1150 to 1300 μM. The sulfur speciation of Cinder Pool is unique in that the thiosulfate and polythionate concentrations are significantly higher than for any other acid-sulfate spring yet sampled in Yellowstone National Park. Complementary laboratory experiments show that thiosulfate is the intermediate sulfoxyanion formed from sulfur hydrolysis under conditions similar to those found in Cinder Pool and that polythionates are formed via the oxidation of thiosulfate by dissolved oxygen. This last reaction is catalyzed by pyrite that occurs as a minor constituent in the sulfur spherules floating on the pool's surface. Polythionate decomposition proceeds via two pathways: (1) a reaction with H2S

  10. Size control in the synthesis of 1-6 nm gold nanoparticles using folic acid-chitosan conjugate as a stabilizer

    NASA Astrophysics Data System (ADS)

    Liu, Lili; Zhang, Xianwen; Chaudhuri, Jharna

    2014-09-01

    We report a simple and practical method for the preparation of folic acid (FA)-chitosan functionalized gold nanoparticles (AuNPs) with a very small size (1-6 nm). Sodium borohydride was used as a reducing agent. The size of the AuNPs was controlled by adjusting the mass fraction of FA-chitosan conjugate to Au. The AuNPs were characterized using UV-vis spectroscopy and transmission electron microscopy (TEM). The results indicated that the size distribution of AuNPs decreased ranging from 6 nm to 1 nm with increasing the fraction of FA-chitosan conjugate in the reaction systems.

  11. Synaptic vesicle pools: an update.

    PubMed

    Denker, Annette; Rizzoli, Silvio O

    2010-01-01

    During the last few decades synaptic vesicles have been assigned to a variety of functional and morphological classes or "pools". We have argued in the past (Rizzoli and Betz, 2005) that synaptic activity in several preparations is accounted for by the function of three vesicle pools: the readily releasable pool (docked at active zones and ready to go upon stimulation), the recycling pool (scattered throughout the nerve terminals and recycling upon moderate stimulation), and finally the reserve pool (occupying most of the vesicle clusters and only recycling upon strong stimulation). We discuss here the advancements in the vesicle pool field which took place in the ensuing years, focusing on the behavior of different pools under both strong stimulation and physiological activity. Several new findings have enhanced the three-pool model, with, for example, the disparity between recycling and reserve vesicles being underlined by the observation that the former are mobile, while the latter are "fixed". Finally, a number of altogether new concepts have also evolved such as the current controversy on the identity of the spontaneously recycling vesicle pool. PMID:21423521

  12. Determination of free silica in dust particles: effect of particle size for the X-ray diffraction and phosphoric acid methods.

    PubMed

    Yabuta, Juji; Ohta, Hisayosi

    2003-07-01

    The X-ray diffraction method and the phosphoric acid method are widely used to determine the fraction of free silica (mainly quartz and other silica polymorphs) in respirable dust sampled in working environments in Japan. In this study, we clarified the size effect of quartz dust for the X-ray diffraction method and the phosphoric acid method using size controlled quartz samples. The quartz samples were classified into 6 fractions with different size ranges: 1 microm and smaller, 1 to 3 microm, 3 to 5 microm, 5 to 7 microm, 7 to 10 microm and 10 microm and larger. Both of the determination methods were affected by the particle size, and especially particles smaller than 3 microm fairly dissolved in hot phosphoric acid and reduced X-ray diffraction intensity remarkably. If the content of these fine particles in the standard quartz sample is lower than that of the test samples, the fraction of free silica may be underestimated by these methods. For this reason, the standard quartz sample should have a representative size distribution of the field samples. The dust samples containing quartz were collected at a foundry and dissolved by phosphoric acid to remove non-quartz materials. The size fractions of dissolved samples were 50% for 5-10 microm, 25% for 3-5 microm, 20% for 1-3 microm and 5% for 1 microm and smaller. As the size distribution is similar to the present standard sample widely used in Japan, we concluded that the standard sample is suitable for these determination methods. PMID:12916756

  13. Incorporation of Root and Surface Litter Inputs Into Soil C Pools: What Do Different Physical Fractionation Approaches Tell Us?

    NASA Astrophysics Data System (ADS)

    Jastrow, J. D.; Swanston, C. W.; O'Brien, S. L.; Moran, K. K.; Porras, R. C.; Torn, M. S.

    2008-12-01

    Efforts to isolate soil C pools related to the structure, function and turnover of soil organic matter (SOM) often employ physical fractionation methods. Both density-based and particle-size fractionations have been used to examine the role of aggregates in SOM cycling and stabilization. After a 14C pulse labeling of deciduous forest, reciprocal transplants of enriched vs. near-background litter allowed us to track the source and dynamics of SOM pools isolated by both fractionation approaches. Light fraction (LF) and particulate organic matter (POM) were separated into unprotected and aggregate-protected pools by applying different dispersion energies. The mineral-associated pool was characterized either as the dense fraction (DF) or as particles <53 μm (MOM). We used procedural constraints and the distributions of bulk soil C and 14C to compare pools isolated by each method. The uPOM fraction included both free and macroaggregate-associated particulate C pools, whereas the free LF isolated mostly unprotected, interstitial particulate C. Operationally, the mPOM fraction consisted of microaggregate-protected particulate C, but the occluded LF included both macroaggregate-associated and microaggregate-protected C. Overall, POM accounted for 5% more of bulk soil C than LF, with the difference likely due to inclusion of some microaggregate-protected particulate C in the DF. POM/LF-C dynamics associated with root turnover occurred mostly at the macroaggregate rather than the microaggregate scale during the 4-y study. In contrast, the dynamics of litter C sources occurred at both scales suggesting a different mode of incorporation, e.g., sorption of soluble C to exchange sites or assimilation by microbes associated with the POM/LF. Acid hydrolysis of the MOM fraction revealed dynamic components that rapidly incorporated and cycled C inputs from both root and litter sources. Taken together, the results improve our understanding of short-term soil C dynamics and the C

  14. A simplified model of decontamination by BWR steam suppression pools

    SciTech Connect

    Powers, D.A.

    1997-05-01

    Phenomena that can decontaminate aerosol-laden gases sparging through steam suppression pools of boiling water reactors during reactor accidents are described. Uncertainties in aerosol properties, aerosol behavior within gas bubbles, and bubble behavior in plumes affect predictions of decontamination by steam suppression pools. Uncertainties in the boundary and initial conditions that are dictated by the progression of severe reactor accidents and that will affect predictions of decontamination by steam suppression pools are discussed. Ten parameters that characterize boundary and initial condition uncertainties, nine parameters that characterize aerosol property and behavior uncertainties, and eleven parameters that characterize uncertainties in the behavior of bubbles in steam suppression pools are identified. Ranges for the values of these parameters and subjective probability distributions for parametric values within the ranges are defined. These uncertain parameters are used in Monte Carlo uncertainty analyses to develop uncertainty distributions for the decontamination that can be achieved by steam suppression pools and the size distribution of aerosols that do emerge from such pools. A simplified model of decontamination by steam suppression pools is developed by correlating features of the uncertainty distributions for total decontamination factor, DF(total), mean size of emerging aerosol particles, d{sub p}, and the standard deviation of the emerging aerosol size distribution, {sigma}, with pool depth, H. Correlations of the median values of the uncertainty distributions are suggested as the best estimate of decontamination by suppression pools. Correlations of the 10 percentile and 90 percentile values of the uncertainty distributions characterize the uncertainty in the best estimates. 295 refs., 121 figs., 113 tabs.

  15. New England salt marsh pools: A quantitative analysis of geomorphic and geographic features

    USGS Publications Warehouse

    Adamowicz, S.C.; Roman, C.T.

    2005-01-01

    New England salt marsh pools provide important wildlife habitat and are the object of on-going salt marsh restoration projects; however, they have not been quantified in terms of their basic geomorphic and geographic traits. An examination of 32 ditched and unditched salt marshes from the Connecticut shore of Long Island Sound to southern Maine, USA, revealed that pools from ditched and unditched marshes had similar average sizes of about 200 m2, averaged 29 cm in depth, and were located about 11 m from the nearest tidal flow. Unditched marshes had 3 times the density (13 pools/ha), 2.5 times the pool coverage (83 m pool/km transect), and 4 times the total pool surface area per hectare (913 m2 pool/ha salt marsh) of ditched sites. Linear regression analysis demonstrated that an increasing density of ditches (m ditch/ha salt marsh) was negatively correlated with pool density and total pool surface area per hectare. Creek density was positively correlated with these variables. Thus, it was not the mere presence of drainage channels that were associated with low numbers of pools, but their type (ditch versus creek) and abundance. Tidal range was not correlated with pool density or total pool surface area, while marsh latitude had only a weak relationship to total pool surface area per hectare. Pools should be incorporated into salt marsh restoration planning, and the parameters quantified here may be used as initial design targets.

  16. Electrical and electrochemical characterization of nano-sized LiFePO4 cathode materials synthesized by a lauric acid-based sol--gel method

    NASA Astrophysics Data System (ADS)

    Bazzi, Khadije; Dixit, Ambesh; Naik, Ratna; Naik, Vaman; Vaishnava, Prem; Nazri, Abbas; Nazri, Mariam

    2011-04-01

    We synthesized pure LiFePO4 and C-LiFePO4 nanoparticles by sol-gel technique. Carbon coating was accomplished by including Lauric acid in the sol-gel precursor solution. Three C-LiFePO4 samples of particle sizes 29, 27, 23 nm, were prepared by varying lauric acid concentration in the precursor solution. All the samples were characterized by X-ray diffraction, Raman, conductivity, and electrochemical measurements. The micro-Raman measurements showed two major bands at 1350 and 1590 cm-1 respectively (ID/IG) and the electronic conductivity were found to depend strongly on the amount of surfactant coverage. The 23 nm particle size sample showed minimum (D/G) band ratio and the maximum electrical conductivity among the three samples. The measured value of the capacity for 23 nm sized sample, ˜ 170 mAh/g, approached the theoretical capacity limit value for LiFePO4

  17. Electrical and electrochemical characterization of nano-sized LiFePO4 cathode materials synthesized by a lauric acid-based sol--gel method

    NASA Astrophysics Data System (ADS)

    Bazzi, Khadije; Dixit, Ambesh; Sahana, M. B.; Sudakar, C.; Nazri, M.; Vaishnava, P. P.; Naik, V.; Nazri, G. A.; Naik, R.

    2011-03-01

    We synthesized pure LiFe PO4 and C- LiFe PO4 nanoparticles by sol-gel technique. Carbon coating was accomplished by including Lauric acid in the sol-gel precursor solution. Three C- LiFe PO4 samples of particle sizes 29, 27, 23 nm, were prepared by varying lauric acid concentration in the precursor solution.~ All the samples were~characterized~by X-ray diffraction, Raman, conductivity, and electrochemical measurements. The micro-Raman measurements showed two major bands at ~ 1585 cm-1 (G) and at ~ 1345 cm-1 (D) in all the C- LiFe PO4 samples.~ The 23 nm particle size sample showed minimum (D/G) band ratio and the maximum electrical conductivity among the three samples. The measured value of the capacity for 23 nm sized sample,~ ~ 170 mAh/g, approached the theoretical capacity limit value for LiFe PO4

  18. Corium quench in deep pool mixing experiments

    SciTech Connect

    Spencer, B.W.; McUmber, L.; Gregorash, D.; Aeschlimann, R.; Sienicki, J.J.

    1985-01-01

    The results of two recent corium-water thermal interaction (CWTI) tests are described in which a stream of molten corium was poured into a deep pool of water in order to determine the mixing behavior, the corium-to-water heat transfer rates, and the characteristic sizes of the quenched debris. The corium composition was 60% UO/sub 2/, 16% ZrO/sub 2/, and 24% stainless steel by weight; its initial temperature was 3080 K, approx.160 K above the oxide phase liquidus temperature. The corium pour stream was a single-phase 2.2 cm dia liquid column which entered the water pool in film boiling at approx.4 m/s. The water subcooling was 6 and 75C in the two tests. Test results showed that with low subcooling, rapid steam generation caused the pool to boil up into a high void fraction regime. In contrast, with large subcooling no net steam generation occurred, and the pool remained relatively quiescent. Breakup of the jet appeared to occur by surface stripping. In neither test was the breakup complete during transit through the 32 cm deep water pool, and molten corium channeled to the base where it formed a melt layer. The characteristic heat transfer rates measured 3.5 MJ/s and 2.7 MJ/s during the fall stage for small and large subcooling, respectively; during the initial stage of bed quench, the surface heat fluxes measured 2.4 MW/m/sup 2/ and 3.7 MW/m/sup 2/, respectively. A small mass of particles was formed in each test, measuring typically 0.1 to 1 mm and 1 to 5 mm dia for the large and small subcooling conditions, respectively. 9 refs., 13 figs., 1 tab.

  19. Tidal Pools--Miniature Oceans

    ERIC Educational Resources Information Center

    Plake, Linda Perry

    1977-01-01

    A comprehensive discussion of the biological activity in tidal pools is provided. The importance of environmental factors such as oxygen supply, temperature, salinity, and light is detailed. Plants and animals that might be found in a tidal pool are identified and described. (BT)

  20. Conceptual design for spacelab pool boiling experiment

    NASA Technical Reports Server (NTRS)

    Lienhard, J. H.; Peck, R. E.

    1978-01-01

    A pool boiling heat transfer experiment to be incorporated with a larger two-phase flow experiment on Spacelab was designed to confirm (or alter) the results of earth-normal gravity experiments which indicate that the hydrodynamic peak and minimum pool boiling heat fluxes vanish at very low gravity. Twelve small sealed test cells containing water, methanol or Freon 113 and cylindrical heaters of various sizes are to be built. Each cell will be subjected to one or more 45 sec tests in which the surface heat flux on the heaters is increased linearly until the surface temperature reaches a limiting value of 500 C. The entire boiling process will be photographed in slow-motion. Boiling curves will be constructed from thermocouple and electric input data, for comparison with the motion picture records. The conduct of the experiment will require no more than a few hours of operator time.

  1. Effects of Caffeine and Chlorogenic Acid on Propidium Iodide Accessibility to DNA: Consequences on Genome Size Evaluation in Coffee Tree

    PubMed Central

    NOIROT, M.; BARRE, P.; DUPERRAY, C.; LOUARN, J.; HAMON, S.

    2003-01-01

    Estimates of genome size using flow cytometry can be biased by the presence of cytosolic compounds, leading to pseudo‐intraspecific variation in genome size. Two important compounds present in coffee trees—caffeine and chlorogenic acid—modify accessibility of the dye propidium iodide to Petunia DNA, a species used as internal standard in our genome size evaluation. These compounds could be responsible for intraspecific variation in genome size since their contents vary between trees. They could also be implicated in environmental variations in genome size, such as those revealed when comparing the results of evaluations carried out on different dates on several genotypes. PMID:12876189

  2. Design of hydrotherapy exercise pools.

    PubMed

    Edlich, R F; Abidin, M R; Becker, D G; Pavlovich, L J; Dang, M T

    1988-01-01

    Several hydrotherapy pools have been designed specifically for a variety of aquatic exercise. Aqua-Ark positions the exerciser in the center of the pool for deep-water exercise. Aqua-Trex is a shallow underwater treadmill system for water walking or jogging. Swim-Ex generates an adjustable laminar flow that permits swimming without turning. Musculoskeletal conditioning can be accomplished in the above-ground Arjo shallow-water exercise pool. A hydrotherapy pool also can be custom designed for musculoskeletal conditioning in its shallow part and cardiovascular conditioning in a deeper portion of the pool. Regardless of the type of exercise, there is general agreement that the specific exercise conducted in water requires significantly more energy expenditure than when the same exercise is performed on land. PMID:3192611

  3. Expansion of IgG+ B-cells during mitogen stimulation for memory B-cell ELISpot analysis is influenced by size and composition of the B-cell pool.

    PubMed

    Scholzen, Anja; Nahrendorf, Wiebke; Langhorne, Jean; Sauerwein, Robert W

    2014-01-01

    The memory B-cell (MBC) ELISpot assay is the main technique used to measure antigen-specific MBCs as a readout of humoral immune memory. This assay relies on the ability of MBCs to differentiate into antibody-secreting cells (ASC) upon polyclonal stimulation. The total number of IgG+ ASCs generated by mitogen-stimulation is often used as a reference point; alternatively antigen-specific MBCs are expressed as a frequency of post-culture peripheral blood mononuclear cells (PBMC) as a surrogate for absolute frequencies. Therefore, it is important to know whether IgG+ B-cells are uniformly expanded during the preceding mitogen-culture as a true reflection of MBC frequencies ex vivo. We systematically compared B-cell phenotype and proportions before and after mitogen stimulation in cultures of 269 peripheral blood mononuclear cell samples from 62 volunteers by flow cytometry and analyzed the number of resulting ASCs. Our data show that the number of total IgG+ ASCs detected by ELISpot after mitogen stimulation correlates with the proportion of IgG+ MBCs ex vivo, highlighting its general robustness for comparisons of study cohorts at group level. The expansion of total and IgG+ B-cells during mitogen-stimulation, however, was not identical in all cultures, but influenced by size and composition of the ex vivo B-cell compartment. The uncorrected readout of antigen-specific MBCs per million post-culture PBMCs therefore only preserves the quality, but not the magnitude of differences in the ex vivo MBC response between groups or time points, particularly when comparing samples where the B-cell compartment substantially differs between cohorts or over time. Therefore, expressing antigen-specific cells per total IgG+ ASCs is currently the best measure to correct for mitogen-culture effects. Additionally, baseline information on the size and composition of the ex vivo B-cell compartment should be supplied to additionally inform about differences or changes in the size and

  4. Controls on Filling and Evacuation of Sediment in Waterfall Plunge Pools

    NASA Astrophysics Data System (ADS)

    Scheingross, J. S.; Lamb, M. P.

    2014-12-01

    Many waterfalls are characterized by the presence of deep plunge pools that experience periods of sediment fill and evacuation. These cycles of sediment fill are a first order control on the relative magnitude of lateral versus vertical erosion at the base of waterfalls, as vertical incision requires cover-free plunge pools to expose the bedrock floor, while lateral erosion can occur when pools are partially filled and plunge-pool walls are exposed. Currently, there exists no mechanistic model describing sediment transport through waterfall plunge pools, limiting our ability to predict waterfall retreat. To address this knowledge gap, we performed detailed laboratory experiments measuring plunge-pool sediment transport capacity (Qsc_pool) under varying waterfall and plunge-pool geometries, flow hydraulics, and sediment size. Our experimental plunge-pool sediment transport capacity measurements match well with a mechanistic model we developed which combines existing waterfall jet theory with a modified Rouse profile to predict sediment transport capacity as a function of water discharge and suspended sediment concentration at the plunge-pool lip. Comparing the transport capacity of plunge pools to lower gradient portions of rivers (Qsc_river) shows that, for transport limited conditions, plunge pools fill with sediment under modest water discharges when Qsc_river > Qsc_pool, and empty to bedrock under high discharges when Qsc_pool > Qsc_river. These results are consistent with field observations of sand-filled plunge pools with downstream boulder rims, implying filling and excavation of plunge pools over single-storm timescales. Thus, partial filling of waterfall plunge pools may provide a mechanism to promote lateral undercutting and retreat of waterfalls in homogeneous rock in which plunge-pool vertical incision occurs during brief large floods that expose bedrock, whereas lateral erosion may prevail during smaller events.

  5. Sediment transport through self-adjusting, bedrock-walled waterfall plunge pools

    NASA Astrophysics Data System (ADS)

    Scheingross, Joel S.; Lamb, Michael P.

    2016-05-01

    Many waterfalls have deep plunge pools that are often partially or fully filled with sediment. Sediment fill may control plunge-pool bedrock erosion rates, partially determine habitat availability for aquatic organisms, and affect sediment routing and debris flow initiation. Currently, there exists no mechanistic model to describe sediment transport through waterfall plunge pools. Here we develop an analytical model to predict steady-state plunge-pool depth and sediment-transport capacity by combining existing jet theory with sediment transport mechanics. Our model predicts plunge-pool sediment-transport capacity increases with increasing river discharge, flow velocity, and waterfall drop height and decreases with increasing plunge-pool depth, radius, and grain size. We tested the model using flume experiments under varying waterfall and plunge-pool geometries, flow hydraulics, and sediment size. The model and experiments show that through morphodynamic feedbacks, plunge pools aggrade to reach shallower equilibrium pool depths in response to increases in imposed sediment supply. Our theory for steady-state pool depth matches the experiments with an R2 value of 0.8, with discrepancies likely due to model simplifications of the hydraulics and sediment transport. Analysis of 75 waterfalls suggests that the water depths in natural plunge pools are strongly influenced by upstream sediment supply, and our model provides a mass-conserving framework to predict sediment and water storage in waterfall plunge pools for sediment routing, habitat assessment, and bedrock erosion modeling.

  6. Merits and Limitations of Vesicle Pool Models in View of Heterogeneous Populations of Synaptic Vesicles.

    PubMed

    Neher, Erwin

    2015-09-23

    The concept of a readily releasable pool (RRP) of synaptic vesicles has been used extensively for the analysis of neurotransmitter release. Traditionally the properties of vesicles in such a pool have been assumed to be homogeneous, and techniques have been developed to determine pool parameters, such as the size of the pool and the probability with which a vesicle is released during an action potential. Increasing evidence, however, indicates that vesicles may be quite heterogeneous with respect to their release probability. The question, therefore, arises: what do the estimates of pool parameters mean in view of such heterogeneity? Here, four methods for obtaining pool estimates are reviewed, together with their underlying assumptions. The consequences of violation of these assumptions are discussed, and how apparent pool sizes are influenced by stimulation strength is explored by simulations.

  7. Dicarboxylic acids, oxoacids, benzoic acid, α-dicarbonyls, WSOC, OC, and ions in spring aerosols from Okinawa Island in the western North Pacific Rim: size distributions and formation processes

    NASA Astrophysics Data System (ADS)

    Deshmukh, D. K.; Kawamura, K.; Lazaar, M.; Kunwar, B.; Boreddy, S. K. R.

    2015-09-01

    Size-segregated aerosols (9-stages from < 0.43 to > 11.3 μm in diameter) were collected at Cape Hedo, Okinawa in spring 2008 and analyzed for water-soluble diacids (C2-C12), ω-oxoacids (ωC2-ωC9), pyruvic acid, benzoic acid and α-dicarbonyls (C2-C3) as well as water-soluble organic carbon (WSOC), organic carbon (OC) and major ions. In all the size-segregated aerosols, oxalic acid (C2) was found as the most abundant species followed by malonic and succinic acids whereas glyoxylic acid (ωC2) was the dominant oxoacid and glyoxal (Gly) was more abundant than methylglyoxal. Diacids (C2-C5), ωC2 and Gly as well as WSOC and OC peaked at 0.65-1.1 μm in fine mode whereas azelaic (C9) and 9-oxononanoic (ωC9) acids peaked at 3.3-4.7 μm in coarse mode. Sulfate and ammonium are enriched in fine mode whereas sodium and chloride are in coarse mode. These results imply that water-soluble species in the marine aerosols could act as cloud condensation nuclei (CCN) to develop the cloud cover over the western North Pacific Rim. The organic species are likely produced by a combination of gas-phase photooxidation, and aerosol-phase or in-cloud processing during long-range transport. The coarse mode peaks of malonic and succinic acids were obtained in the samples with marine air masses, suggesting that they may be associated with the reaction on sea salt particles. Bimodal size distributions of longer-chain diacid (C9) and oxoacid (ωC9) with a major peak in the coarse mode suggest their production by photooxidation of biogenic unsaturated fatty acids via heterogeneous reactions on sea salt particles.

  8. Internalization and cellular pools of never growth factor in pheochromocytoma (PC12) cells

    SciTech Connect

    Neet, K.E.; Kasaian, M.

    1987-05-01

    Nerve Growth Factor (NGF) binds to a cell surface receptor on responsive neuronal cells to initiate cell maintenance and/or differentiation regimes. The purpose of these studies was to define quantitatively the fate of NGF in PC12 cells with respect to various cellular compartments in a single series of biochemical experiments. Different binding methodologies were evaluated in suspension and on plates. 50 pM SVI-NGF was bound to rat PC12 cells in suspension for 30 min at 37, followed by various methods and combinations of methods to remove subsets of bound ligand. Distinction could be made between NGF bound to fast vs. slow cell surface receptors, NGF bound to slow receptors at the cell surface vs. cell interior, and detergent-soluble vs. cytoskeletally-attached NGF. These treatments defined the relative size of five pools, including the fast receptor (65%), two intracellular compartments (12% and 3%) susceptible to nonionic detergent, and a detergent-stable intracellular pool of ligand (16%). At 37 the cold chase stable and the acid stable pools were about the same size because of rapid internalization, but the slow receptor was measurable at 4. Inhibitors were used to define the route of NGF through the cell from the plasma membrane to degradation. Chloroquine caused accumulation of NGF only in pools that were not associated with the cytoskeleton, implicating this compartment in supplying ligand to the lysosome. Results with cytochalasin B and colchicine and suggested both microfilament and microtubule pathways in NGF degradation. A model for the movement of NGF through the cell was developed based on these observations.

  9. 13 CFR 120.1708 - Pool Certificates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Pool Certificates. 120.1708... of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1708 Pool Certificates. (a) SBA Guarantee of Pool Certificates. SBA guarantees to a Pool Investor the timely payment...

  10. 13 CFR 120.1708 - Pool Certificates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Pool Certificates. 120.1708... of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1708 Pool Certificates. (a) SBA Guarantee of Pool Certificates. SBA guarantees to a Pool Investor the timely payment...

  11. 13 CFR 120.1708 - Pool Certificates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Pool Certificates. 120.1708... of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1708 Pool Certificates. (a) SBA Guarantee of Pool Certificates. SBA guarantees to a Pool Investor the timely payment...

  12. 13 CFR 120.1708 - Pool Certificates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Pool Certificates. 120.1708... of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1708 Pool Certificates. (a) SBA Guarantee of Pool Certificates. SBA guarantees to a Pool Investor the timely payment...

  13. 13 CFR 120.1708 - Pool Certificates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Pool Certificates. 120.1708... of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1708 Pool Certificates. (a) SBA Guarantee of Pool Certificates. SBA guarantees to a Pool Investor the timely payment...

  14. Size-controlled synthesis and formation mechanism of manganese oxide OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids

    NASA Astrophysics Data System (ADS)

    Zhang, Qin; Cheng, Xiaodi; Qiu, Guohong; Liu, Fan; Feng, Xionghan

    2016-05-01

    This study presents a simplified approach for size-controlled synthesis of manganese oxide octahedral molecular sieve (OMS-2) nanowires using potassium permanganate (KMnO4) and different inorganic acids (HCl, HNO3, and H2SO4) under reflux conditions. The morphology and nanostructure of the synthesized products are characterized by X-ray diffraction, Ar adsorption, and electron microscopy analysis, in order to elucidate the controlling effects of acid concentration and type as well as the formation mechanism of OMS-2 nanowires. The concentration of inorganic acid is a crucial factor controlling the phase of the synthesized products. OMS-2 nanowires are obtained with HCl at the concentration ≥0.96 mol/L or with HNO3 and H2SO4 at the concentrations ≥0.72 mol/L. Differently, the type of inorganic acid effectively determines the particle size of OMS-2 nanowires. When the acid is changed from HCl to HNO3 and H2SO4 in the reflux system, the average length of OMS-2 declines significantly by 60-70% (1104-442 and 339 nm), with minor decreased in the average width (43-39 and 34 nm). The formation of OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids involves a two-step process, i.e., the initial formation of layered manganese oxides, and subsequent transformation to OMS-2 via a dissolution-recrystallization process under acidic conditions. The proposed reflux route provides an alternative approach for synthesizing OMS-2 nanowires as well as other porous nano-crystalline OMS materials.

  15. Size-controlled synthesis and formation mechanism of manganese oxide OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids

    NASA Astrophysics Data System (ADS)

    Zhang, Qin; Cheng, Xiaodi; Qiu, Guohong; Liu, Fan; Feng, Xionghan

    2016-05-01

    This study presents a simplified approach for size-controlled synthesis of manganese oxide octahedral molecular sieve (OMS-2) nanowires using potassium permanganate (KMnO4) and different inorganic acids (HCl, HNO3, and H2SO4) under reflux conditions. The morphology and nanostructure of the synthesized products are characterized by X-ray diffraction, Ar adsorption, and electron microscopy analysis, in order to elucidate the controlling effects of acid concentration and type as well as the formation mechanism of OMS-2 nanowires. The concentration of inorganic acid is a crucial factor controlling the phase of the synthesized products. OMS-2 nanowires are obtained with HCl at the concentration ≥0.96 mol/L or with HNO3 and H2SO4 at the concentrations ≥0.72 mol/L. Differently, the type of inorganic acid effectively determines the particle size of OMS-2 nanowires. When the acid is changed from HCl to HNO3 and H2SO4 in the reflux system, the average length of OMS-2 declines significantly by 60-70% (1104-442 and 339 nm), with minor decreased in the average width (43-39 and 34 nm). The formation of OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids involves a two-step process, i.e., the initial formation of layered manganese oxides, and subsequent transformation to OMS-2 via a dissolution-recrystallization process under acidic conditions. The proposed reflux route provides an alternative approach for synthesizing OMS-2 nanowires as well as other porous nano-crystalline OMS materials.

  16. Ulk4 Regulates Neural Stem Cell Pool.

    PubMed

    Liu, Min; Guan, Zhenlong; Shen, Qin; Flinter, Frances; Domínguez, Laura; Ahn, Joo Wook; Collier, David A; O'Brien, Timothy; Shen, Sanbing

    2016-09-01

    The size of neural stem cell (NSC) pool at birth determines the starting point of adult neurogenesis. Aberrant neurogenesis is associated with major mental illness, in which ULK4 is proposed as a rare risk factor. Little is known about factors regulating the NSC pool, or function of the ULK4. Here, we showed that Ulk4(tm1a/tm1a) mice displayed a dramatically reduced NSC pool at birth. Ulk4 was expressed in a cell cycle-dependent manner and peaked in G2/M phases. Targeted disruption of the Ulk4 perturbed mid-neurogenesis and significantly reduced cerebral cortex in postnatal mice. Pathway analyses of dysregulated genes in Ulk4(tm1a/tm1a) mice revealed Ulk4 as a key regulator of cell cycle and NSC proliferation, partially through regulation of the Wnt signaling. In addition, we identified hemizygous deletion of ULK4 gene in 1.2/1,000 patients with pleiotropic symptoms including severe language delay and learning difficulties. ULK4, therefore, may significantly contribute to neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. Stem Cells 2016;34:2318-2331.

  17. Ulk4 Regulates Neural Stem Cell Pool.

    PubMed

    Liu, Min; Guan, Zhenlong; Shen, Qin; Flinter, Frances; Domínguez, Laura; Ahn, Joo Wook; Collier, David A; O'Brien, Timothy; Shen, Sanbing

    2016-09-01

    The size of neural stem cell (NSC) pool at birth determines the starting point of adult neurogenesis. Aberrant neurogenesis is associated with major mental illness, in which ULK4 is proposed as a rare risk factor. Little is known about factors regulating the NSC pool, or function of the ULK4. Here, we showed that Ulk4(tm1a/tm1a) mice displayed a dramatically reduced NSC pool at birth. Ulk4 was expressed in a cell cycle-dependent manner and peaked in G2/M phases. Targeted disruption of the Ulk4 perturbed mid-neurogenesis and significantly reduced cerebral cortex in postnatal mice. Pathway analyses of dysregulated genes in Ulk4(tm1a/tm1a) mice revealed Ulk4 as a key regulator of cell cycle and NSC proliferation, partially through regulation of the Wnt signaling. In addition, we identified hemizygous deletion of ULK4 gene in 1.2/1,000 patients with pleiotropic symptoms including severe language delay and learning difficulties. ULK4, therefore, may significantly contribute to neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. Stem Cells 2016;34:2318-2331. PMID:27300315

  18. Effects of acidity on the size of polyaniline-poly(sodium 4-styrenesulfonate) composite particles and the stability of corresponding colloids in water.

    PubMed

    Li, Ligui; Ferng, Linhui; Wei, Yen; Yang, Catherine; Ji, Hai-Feng

    2012-09-01

    The practical application of polyaniline-poly(sodium 4-styrenesulfonate) (PANI-PSS) composite particles has been held back by the low stability of their dispersed state in water. In this work, we present a general oxidation approach to prepare PANI-PSS composite nanoparticles that can form highly stable colloids in water or buffer over a wide range of pH from 1 to 11. We demonstrate that the size of the PANI-PSS composite particles can be controlled by the acidity of precursor solutions. It is hypothesized that the number of negatively charged sites on PSS, which can be affected by the acidity of the precursor solutions, plays an important role in determining the size of the PANI-PSS composite particles and the stability of corresponding colloids in water. PMID:22647343

  19. The effect of oleic acid on the synthesis of Fe(3-x)O4 nanoparticles over a wide size range.

    PubMed

    Moya, Carlos; Batlle, Xavier; Labarta, Amílcar

    2015-11-01

    This work reports on the effect of the oleic acid concentration on the magnetic and structural properties of Fe3-xO4 nanoparticles synthesized by thermal decomposition of Fe(acac)3 in benzyl-ether. This method allows the synthesis of highly monodisperse particles ranging from 7 to 100 nm in size by only varying the concentration of oleic acid in the reaction mixture. The structural and magnetic characterization reveal homogeneous particles in composition, with narrow particle size distribution, which are single-phase magnetite with almost bulk-like values of the saturation magnetization of about 90-99 emu g(-1) at low temperatures and show the characteristic anomaly in the zero field-cooling magnetization curves associated with the Verwey transition for nanoparticles bigger than about 7 nm. In addition, the analyses of aliquots of the reaction mixtures by Fourier transform infrared spectroscopy at various stages shed light on the nucleation and growth processes of the particles.

  20. Effects of acidity on the size of polyaniline-poly(sodium 4-styrenesulfonate) composite particles and the stability of corresponding colloids in water.

    PubMed

    Li, Ligui; Ferng, Linhui; Wei, Yen; Yang, Catherine; Ji, Hai-Feng

    2012-09-01

    The practical application of polyaniline-poly(sodium 4-styrenesulfonate) (PANI-PSS) composite particles has been held back by the low stability of their dispersed state in water. In this work, we present a general oxidation approach to prepare PANI-PSS composite nanoparticles that can form highly stable colloids in water or buffer over a wide range of pH from 1 to 11. We demonstrate that the size of the PANI-PSS composite particles can be controlled by the acidity of precursor solutions. It is hypothesized that the number of negatively charged sites on PSS, which can be affected by the acidity of the precursor solutions, plays an important role in determining the size of the PANI-PSS composite particles and the stability of corresponding colloids in water.

  1. Reserve growth in oil pools of Alberta: Model and forecast

    USGS Publications Warehouse

    Verma, M.; Cook, T.

    2010-01-01

    Reserve growth is recognized as a major component of additions to reserves in most oil provinces around the world, particularly in mature provinces. It takes place as a result of the discovery of new pools/reservoirs and extensions of known pools within existing fields, improved knowledge of reservoirs over time leading to a change in estimates of original oil-in-place, and improvement in recovery factor through the application of new technology, such as enhanced oil recovery methods, horizontal/multilateral drilling, and 4D seismic. A reserve growth study was conducted on oil pools in Alberta, Canada, with the following objectives: 1) evaluate historical oil reserve data in order to assess the potential for future reserve growth; 2) develop reserve growth models/ functions to help forecast hydrocarbon volumes; 3) study reserve growth sensitivity to various parameters (for example, pool size, porosity, and oil gravity); and 4) compare reserve growth in oil pools and fields in Alberta with those from other large petroleum provinces around the world. The reported known recoverable oil exclusive of Athabasca oil sands in Alberta increased from 4.5 billion barrels of oil (BBO) in 1960 to 17 BBO in 2005. Some of the pools that were included in the existing database were excluded from the present study for lack of adequate data. Therefore, the known recoverable oil increased from 4.2 to 13.9 BBO over the period from 1960 through 2005, with new discoveries contributing 3.7 BBO and reserve growth adding 6 BBO. This reserve growth took place mostly in pools with more than 125,000 barrels of known recoverable oil. Pools with light oil accounted for most of the total known oil volume, therefore reflecting the overall pool growth. Smaller pools, in contrast, shrank in their total recoverable volumes over the years. Pools with heavy oil (gravity less than 20o API) make up only a small share (3.8 percent) of the total recoverable oil; they showed a 23-fold growth compared to

  2. 13 CFR 120.1706 - Pool Originator's retained interest in Pool.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Pool Originator's retained interest in Pool. 120.1706 Section 120.1706 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... Pools § 120.1706 Pool Originator's retained interest in Pool. The Pool Originator must retain...

  3. 13 CFR 120.1706 - Pool Originator's retained interest in Pool.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Pool Originator's retained interest in Pool. 120.1706 Section 120.1706 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... Pools § 120.1706 Pool Originator's retained interest in Pool. The Pool Originator must retain...

  4. 13 CFR 120.1706 - Pool Originator's retained interest in Pool.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Pool Originator's retained interest in Pool. 120.1706 Section 120.1706 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... Pools § 120.1706 Pool Originator's retained interest in Pool. The Pool Originator must retain...

  5. 13 CFR 120.1706 - Pool Originator's retained interest in Pool.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Pool Originator's retained interest in Pool. 120.1706 Section 120.1706 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... Pools § 120.1706 Pool Originator's retained interest in Pool. The Pool Originator must retain...

  6. 13 CFR 120.1706 - Pool Originator's retained interest in Pool.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Pool Originator's retained interest in Pool. 120.1706 Section 120.1706 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION... Pools § 120.1706 Pool Originator's retained interest in Pool. The Pool Originator must retain...

  7. Pool impacts of Leidenfrost drop

    NASA Astrophysics Data System (ADS)

    Darbois Texier, Baptiste; Maquet, Laurent; Dorbolo, Stephane; Dehandschoewercker, Eline; Pan, Zhao; Truscott, Tadd

    2015-11-01

    This work concerns the impact of a droplet made of a volatile liquid (typically HFE) on a pool of an other liquid (typically silicone oil) which temperature is above the boiling point of the drop. Depending on the properties of the two liquids and the impacting conditions, four different regimes are observed. For low impacting speeds, the droplet bounces on the surface of the bath and finally levitates above it in a Leidenfrost state. Such a regime occurs as soon as the pool temperature exceeds the boiling point of the drop. This observation means that there is no threshold in temperature for a Leidenfrost effect on a liquid surface contrary to the case of a solid substrate. For intermediate impacting velocities, the pinch-off of the surface of the pool entraps the drop in the liquid bulk. The entrapped drop is separated from the pool by a layer of its own vapour in a similar way of antibulles. For increasing impacting speeds, the vapour layer between the drop and the pool does not hold during the pinch-off event. The contact of the drop with the hot liquid provokes a sudden and intense evaporation. At very large impacting speeds, the drop rapidely contacts the pool, spreads and finally induces a hemi-spherical cavity. In the end, these four different regimes are summarized in a Froud-Weber diagram which boundaries are discussed.

  8. Interval mapping of quantitative trait loci with selective DNA pooling data

    PubMed Central

    Wang, Jing; Koehler, Kenneth J; Dekkers, Jack CM

    2007-01-01

    Selective DNA pooling is an efficient method to identify chromosomal regions that harbor quantitative trait loci (QTL) by comparing marker allele frequencies in pooled DNA from phenotypically extreme individuals. Currently used single marker analysis methods can detect linkage of markers to a QTL but do not provide separate estimates of QTL position and effect, nor do they utilize the joint information from multiple markers. In this study, two interval mapping methods for analysis of selective DNA pooling data were developed and evaluated. One was based on least squares regression (LS-pool) and the other on approximate maximum likelihood (ML-pool). Both methods simultaneously utilize information from multiple markers and multiple families and can be applied to different family structures (half-sib, F2 cross and backcross). The results from these two interval mapping methods were compared with results from single marker analysis by simulation. The results indicate that both LS-pool and ML-pool provided greater power to detect the QTL than single marker analysis. They also provide separate estimates of QTL location and effect. With large family sizes, both LS-pool and ML-pool provided similar power and estimates of QTL location and effect as selective genotyping. With small family sizes, however, the LS-pool method resulted in severely biased estimates of QTL location for distal QTL but this bias was reduced with the ML-pool. PMID:18053576

  9. Beneficial Effects of Omega-3 Fatty Acids on Low Density Lipoprotein Particle Size in Patients with Type 2 Diabetes Already under Statin Therapy.

    PubMed

    Lee, Myung Won; Park, Jeong Kyung; Hong, Jae Won; Kim, Kwang Joon; Shin, Dong Yeob; Ahn, Chul Woo; Song, Young Duk; Cho, Hong Keun; Park, Seok Won; Lee, Eun Jig

    2013-06-01

    Beyond statin therapy for reducing low density lipoprotein cholesterol (LDL-C), additional therapeutic strategies are required to achieve more optimal reduction in cardiovascular risk among diabetic patients with dyslipidemia. To evaluate the effects and the safety of combined treatment with omega-3 fatty acids and statin in dyslipidemic patients with type 2 diabetes, we conducted a randomized, open-label study in Korea. Patients with persistent hypertriglyceridemia (≥200 mg/dL) while taking statin for at least 6 weeks were eligible. Fifty-one patients were randomized to receive either omega-3 fatty acid 4, 2 g, or no drug for 8 weeks while continuing statin therapy. After 8 weeks of treatment, the mean percentage change of low density lipoprotein (LDL) particle size and triglyceride (TG) level was greater in patients who were prescribed 4 g of omega-3 fatty acid with statin than in patients receiving statin monotherapy (2.8%±3.1% vs. 2.3%±3.6%, P=0.024; -41.0%±24.1% vs. -24.2%±31.9%, P=0.049). Coadministration of omega-3 fatty acids with statin increased LDL particle size and decreased TG level in dyslipidemic patients with type 2 diabetes. The therapy was well tolerated without significant adverse effects.

  10. Molecular composition and size distribution of sugars, sugar-alcohols and carboxylic acids in airborne particles during a severe urban haze event caused by wheat straw burning

    NASA Astrophysics Data System (ADS)

    Wang, Gehui; Chen, Chunlei; Li, Jianjun; Zhou, Bianhong; Xie, Mingjie; Hu, Shuyuan; Kawamura, Kimitaka; Chen, Yan

    2011-05-01

    Molecular compositions and size distributions of water-soluble organic compounds (WSOC, i.e., sugars, sugar-alcohols and carboxylic acids) in particles from urban air of Nanjing, China during a severe haze event caused by field burning of wheat straw were characterized and compared with those in the summer and autumn non-haze periods. During the haze event levoglucosan (4030 ng m -3) was the most abundant compound among the measured WSOC, followed by succinic acid, malic acid, glycerol, arabitol and glucose, being different from those in the non-haze samples, in which sucrose or azelaic acid showed a second highest concentration, although levoglucosan was the highest. The measured WSOC in the haze event were 2-20 times more than those in the non-hazy days. Size distribution results showed that there was no significant change in the compound peaks in coarse mode (>2.1 μm) with respect to the haze and non-haze samples, but a large difference in the fine fraction (<2.1 μm) was found with a sharp increase during the hazy days mostly due to the increased emissions of wheat straw burning. Molecular compositions of organic compounds in the fresh smoke particles from wheat straw burning demonstrate that sharply increased concentrations of glycerol and succinic and malic acids in the fine particles during the haze event were mainly derived from the field burning of wheat straw, although the sources of glucose and related sugar-alcohols whose concentrations significantly increased in the fine haze samples are unclear. Compared to that in the fresh smoke particles of wheat straw burning an increase in relative abundance of succinic acid to levoglucosan during the haze event suggests a significant production of secondary organic aerosols during transport of the smoke plumes.

  11. Assessment of dermal hazard from acid burns with fire retardant garments in a full-size simulation of an engulfment flash fire.

    PubMed

    Mackay, Christopher E; Vivanco, Stephanie N; Yeboah, George; Vercellone, Jeff

    2016-09-01

    There have been concerns that fire-derived acid gases could aggravate thermal burns for individuals wearing synthetic flame retardant garments. A comparative risk assessment was performed on three commercial flame retardant materials with regard to relative hazards associated with acidic combustion gases to skin during a full engulfment flash fire event. The tests were performed in accordance with ASTM F1930 and ISO 13506: Standard Test Method for Evaluation of Flame Resistant Clothing for Protection against Fire Simulations Using an Instrumented Manikin. Three fire retardant textiles were tested: an FR treated cotton/nylon blend, a low Protex(®) modacrylic blend, and a medium Protex(®) modacrylic blend. The materials, in the form of whole body coveralls, were subjected to propane-fired flash conditions of 84kW/m(2) in a full sized simulator for a duration of either 3 or 4s. Ion traps consisting of wetted sodium carbonate-impregnated cellulose in Teflon holders were placed on the chest and back both above and under the standard undergarments. The ion traps remained in position from the time of ignition until 5min post ignition. Results indicated that acid deposition did increase with modacrylic content from 0.9μmol/cm(2) for the cotton/nylon, to 12μmol/cm(2) for the medium modacrylic blend. The source of the acidity was dominated by hydrogen chloride. Discoloration was inversely proportional to the amount of acid collected on the traps. A risk assessment was performed on the potential adverse impact of acid gases on both the skin and open wounds. The results indicated that the deposition and dissolution of the acid gases in surficial fluid media (perspiration and blood plasma) resulted in an increase in acidity, but not sufficient to induce irritation/skin corrosion or to cause necrosis in open third degree burns.

  12. Assessment of dermal hazard from acid burns with fire retardant garments in a full-size simulation of an engulfment flash fire.

    PubMed

    Mackay, Christopher E; Vivanco, Stephanie N; Yeboah, George; Vercellone, Jeff

    2016-09-01

    There have been concerns that fire-derived acid gases could aggravate thermal burns for individuals wearing synthetic flame retardant garments. A comparative risk assessment was performed on three commercial flame retardant materials with regard to relative hazards associated with acidic combustion gases to skin during a full engulfment flash fire event. The tests were performed in accordance with ASTM F1930 and ISO 13506: Standard Test Method for Evaluation of Flame Resistant Clothing for Protection against Fire Simulations Using an Instrumented Manikin. Three fire retardant textiles were tested: an FR treated cotton/nylon blend, a low Protex(®) modacrylic blend, and a medium Protex(®) modacrylic blend. The materials, in the form of whole body coveralls, were subjected to propane-fired flash conditions of 84kW/m(2) in a full sized simulator for a duration of either 3 or 4s. Ion traps consisting of wetted sodium carbonate-impregnated cellulose in Teflon holders were placed on the chest and back both above and under the standard undergarments. The ion traps remained in position from the time of ignition until 5min post ignition. Results indicated that acid deposition did increase with modacrylic content from 0.9μmol/cm(2) for the cotton/nylon, to 12μmol/cm(2) for the medium modacrylic blend. The source of the acidity was dominated by hydrogen chloride. Discoloration was inversely proportional to the amount of acid collected on the traps. A risk assessment was performed on the potential adverse impact of acid gases on both the skin and open wounds. The results indicated that the deposition and dissolution of the acid gases in surficial fluid media (perspiration and blood plasma) resulted in an increase in acidity, but not sufficient to induce irritation/skin corrosion or to cause necrosis in open third degree burns. PMID:27325216

  13. Velocity reversals and sediment sorting in pools and riffles controlled by channel constrictions

    USGS Publications Warehouse

    Thompson, D.M.; Wohl, E.E.; Jarrett, R.D.

    1999-01-01

    Keller [Keller, E.A., 1971. Areal sorting of bed-load material; the hypothesis of velocity reversal. Geological Society of America Bulletin 82, 753-756] hypothesized that at high flow, near-bed velocities in pools exceed velocities in riffles and create pool scour. Pools, however, typically have larger cross-sectional areas of flow at bankfull discharge. This condition raises an inconsistency with Keller's velocity reversal hypothesis and the one-dimensional continuity of mass equation. To address this problem, a model of pool maintenance and sediment sorting is proposed that relies on constriction of flow by recirculating eddies and flow divergence over the exit-slopes of pools. According to the model, a narrow zone of high velocity occurs in the center of pools, creating scour. Along the downstream end of pools, an uphill climb of particles up the pool exit-slope promotes sediment deposition. The model is tested with field and flume measurements of velocity, water-surface elevation, and size of bed sediments in recirculating-eddy influenced pools. Local reversals of the water-surface gradient were measured in the field and a velocity reversal was created in the flume. The reversals that were measured indicate higher gradients of the water surface over the upstream portions of pools and higher velocities in pools at high flow. The distribution of bed sediments collected in the field also support the proposed model of pool maintenance.

  14. Effect of frame size and time-on-pasture on steer performance, longissimus muscle fatty acid composition, and tenderness in a forage-finishing system.

    PubMed

    Duckett, S K; Fernandez Rosso, C; Volpi Lagreca, G; Miller, M C; Neel, J P S; Lewis, R M; Swecker, W S; Fontenot, J P

    2014-10-01

    Angus-cross steers (n = 96; BW = 309 ± 34 kg; 13.5 mo of age) were used to determine the effects of frame size (medium or small) and time-on-pasture (TOP) on meat composition and palatability in a 2-yr study. Finishing steers grazed mixed pastures (bluegrass/white clover; April start) and were slaughtered after 89-, 146-, and 201-d TOP. At 24 h postmortem, carcass traits were collected and a rib from each carcass was obtained for proximate and fatty acid composition, Warner-Bratzler shear force (WBSF), and postmortem proteolysis. In yr 1, postmortem aging treatments included 14 and 28 d, whereas in yr 2, postmortem aging treatments included 2, 4, 7, 14, and 28 d. Increasing frame size of the finishing steers produced greater (P < 0.05) ADG by 0.10 kg, BW by 24 kg, HCW by 14 kg, and ribeye size by 2.65 cm(2). All other carcass, meat composition, and tenderness measures did not differ (P > 0.05) due to frame size or 2-way interaction with TOP. Increasing TOP resulted in quadratic increases (P < 0.01) in BW and HCW. Ribeye area, fat thickness, KPH, marbling scores, quality grades, and yield grades increased (P < 0.001) linearly as TOP increased. Time-on-pasture linearly increased (P = 0.001) palmitic (C16:0) acid, oleic (C18:1 cis-9) acid, SFA, and MUFA in the LM. Both n-6 PUFA, linoleic (C18:2) and arachidonic (C20:4) acids, decreased linearly (P = 0.001) with increasing TOP. Increasing TOP linearly reduced (P = 0.01) concentrations of all n-3 fatty acids in the LM. These changes resulted in a linear reduction (P = 0.01) in n-6 to n-3 fatty acid ratio with advancing TOP; however, the magnitude of the difference was small (1.46 vs. 1.37). At 14 d of postmortem aging, WBSF was lowest (P < 0.001) for 89-d TOP and greatest (P < 0.05) for the 201-d TOP. After 28 d of postmortem aging, WBSF values for 89- and 146-d TOP did not differ (P > 0.05) compared to the 14-d postmortem aging WBSF values. However, in steaks from 201-d TOP, additional postmortem aging to 28 d reduced

  15. The lymph lipid precursor pool is a key determinant of intestinal lymphatic drug transport.

    PubMed

    Trevaskis, Natalie L; Porter, Christopher J H; Charman, William N

    2006-02-01

    The influence of the size and turnover kinetics of the enterocyte-based lymph lipid precursor pool (LLPP) on intestinal lymphatic drug transport has been examined. Mesenteric lymph duct-cannulated rats were infused intraduodenally with low (2-5 mg/h) or high (20 mg/h) lipid-dose formulations containing 100 microg/h halofantrine (Hf, a model drug) and 1 microCi/h (14)C-oleic acid (OA) (as a marker for lipid transport) until steady-state rates of lipid(dX(L)/dt)(ss) and drug (dD(L)/dt)(ss) transport in lymph were obtained. After 5 h, the infusion was changed to formulations of the same composition but excluding (14)C-OA and Hf, allowing calculation of the first order rate constants describing turnover of lipid (K(X)) and drug (K(D)) from the LLPP into the lymph from the washout kinetics. The mass of lipid (X(LP)) and drug (D(LP)) in the LLPP was also determined. Biliary-lipid output was determined in a separate group of rats that had been infused with the same formulations. The results indicate that after administration of high lipid doses, lymphatic drug transport is dependent on the mass of exogenous lipid available in the LLPP and the rate of lipid pool turnover into the lymph. In contrast, after administration of low lipid doses, biliary-derived endogenous lipids are most likely to be the primary drivers of drug incorporation into the LLPP and lymph. Therefore, the LLPP size and composition seem to be major determinants of lymphatic drug transport, and formulation components, which increase lipid pool size, may therefore enhance lymphatic drug transport. PMID:16249368

  16. In situ acidity and pH of size-fractionated aerosols during a recent smoke-haze episode in Southeast Asia.

    PubMed

    Behera, Sailesh N; Cheng, Jinping; Balasubramanian, Rajasekhar

    2015-10-01

    The characterization of aerosol acidity has received increased attention in recent years due to its influence on atmospheric visibility, climate change and human health. Distribution of water soluble inorganic (WSI) ions in 12 different size fractions of aerosols was investigated under two different atmospheric conditions (smoke-haze and non-haze periods) in 2012 using the Micro-Orifice Uniform Deposit Impactor (MOUDI) and nano-MOUDI for the first time in Singapore. To estimate the in situ acidity ([H(+)]Ins) and in situ aerosol pH (pHIS), the Aerosol Inorganic Model version-IV under deliquescent mode of airborne particles was used at prevailing ambient temperature and relative humidity. The study revealed an increase in the levels of airborne particulate matter (PM) mass and concentrations of WSI ions for all size fractions during the smoke-haze period, which was caused by the trans-boundary transport of biomass burning-impacted air masses from Indonesia. A bimodal distribution was observed for concentrations of SO4(2-), NO3(-), Cl(-), K(+) and Na(+), whereas concentrations of NH4(+), Ca(2+) and Mg(2+) showed a single mode distribution. The concentration of WSI ions in PM1.8 during the smoke-haze period increased by 3.8 (for SO4(2-)) to 10.5 (for K(+)) times more than those observed during the non-haze period. The pHIS were observed to be lower during the smoke-haze period than that during the non-haze period for all size fractions of PM, indicating that atmospheric aerosols were more acidic due to the influence of biomass burning emissions. The particles in the accumulation mode were more acidic than those in the coarse mode.

  17. In situ acidity and pH of size-fractionated aerosols during a recent smoke-haze episode in Southeast Asia.

    PubMed

    Behera, Sailesh N; Cheng, Jinping; Balasubramanian, Rajasekhar

    2015-10-01

    The characterization of aerosol acidity has received increased attention in recent years due to its influence on atmospheric visibility, climate change and human health. Distribution of water soluble inorganic (WSI) ions in 12 different size fractions of aerosols was investigated under two different atmospheric conditions (smoke-haze and non-haze periods) in 2012 using the Micro-Orifice Uniform Deposit Impactor (MOUDI) and nano-MOUDI for the first time in Singapore. To estimate the in situ acidity ([H(+)]Ins) and in situ aerosol pH (pHIS), the Aerosol Inorganic Model version-IV under deliquescent mode of airborne particles was used at prevailing ambient temperature and relative humidity. The study revealed an increase in the levels of airborne particulate matter (PM) mass and concentrations of WSI ions for all size fractions during the smoke-haze period, which was caused by the trans-boundary transport of biomass burning-impacted air masses from Indonesia. A bimodal distribution was observed for concentrations of SO4(2-), NO3(-), Cl(-), K(+) and Na(+), whereas concentrations of NH4(+), Ca(2+) and Mg(2+) showed a single mode distribution. The concentration of WSI ions in PM1.8 during the smoke-haze period increased by 3.8 (for SO4(2-)) to 10.5 (for K(+)) times more than those observed during the non-haze period. The pHIS were observed to be lower during the smoke-haze period than that during the non-haze period for all size fractions of PM, indicating that atmospheric aerosols were more acidic due to the influence of biomass burning emissions. The particles in the accumulation mode were more acidic than those in the coarse mode. PMID:25432456

  18. Fluorescent Ag nanoclusters prepared in aqueous poly(acrylic acid-co-maleic acid) solutions: a spectroscopic study of their excited state dynamics, size and local environment.

    PubMed

    Dandapat, Manika; Mandal, Debabrata

    2016-01-28

    Stable, fluorescent Ag nanoclusters were prepared in aqueous solutions of Na(+) salt of the carboxylate-rich polymer poly(acrylic acid-co-maleic acid) under brief spells of UV irradiation. The nanoclusters were nearly spherical, with diameters within 1.90 ± 0.50 nm, but displayed a prominent red edge excitation shift (REES) of fluorescence upon exciting within the visible absorption band, indicating heterogeneity of energy level distributions. Spectroscopic studies revealed that irrespective of whether the nanoclusters are excited in their UV or visible absorption bands, their fluorescence always ensues from the same manifold of emissive states, with a broad range of fluorescence lifetimes from ∼150 fs to 1 ns. PMID:26700465

  19. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  20. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  1. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  2. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  3. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  4. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  5. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  6. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  7. 47 CFR 13.215 - Question pools.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Question pools. 13.215 Section 13.215... Question pools. The question pool for each written examination element will be composed of questions acceptable to the FCC. Each question pool must contain at least five (5) times the number of...

  8. 47 CFR 97.523 - Question pools.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Question pools. 97.523 Section 97.523... SERVICE Qualifying Examination Systems § 97.523 Question pools. All VECs must cooperate in maintaining one question pool for each written examination element. Each question pool must contain at least 10 times...

  9. HYDROLOGY AND LANDSCAPE CONNECTIVITY OF VERNAL POOLS

    EPA Science Inventory

    Vernal pools are shaped by hydrologic processes which influence many aspects of pool function. The hydrologic budget of a pool can be summarized by a water balance equation that relates changes in the amount of water in the pool to precipitation, ground- and surface-water flows, ...

  10. Swimming Pools. Managing School Facilities, Guide 2.

    ERIC Educational Resources Information Center

    Department for Education and Employment, London (England). Architects and Building Branch.

    This guide for schools with swimming pools offers advice concerning appropriate training for pool managers, the importance of water quality and testing, safety in the handling of chemicals, maintenance and cleaning requirements, pool security, and health concerns. The guide covers both indoor and outdoor pools, explains some technical terms,…

  11. 21 CFR 1250.89 - Swimming pools.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Swimming pools. 1250.89 Section 1250.89 Food and... SANITATION Sanitation Facilities and Conditions on Vessels § 1250.89 Swimming pools. (a) Fill and draw swimming pools shall not be installed or used. (b) Swimming pools of the recirculation type shall...

  12. Correlates of vernal pool occurrence in the Massachusetts USA, landscape

    USGS Publications Warehouse

    Grant, E.H.C.

    2005-01-01

    Vernal pool wetlands are at risk of destruction across the northeast United States, due in part to their diminutive size and short hydroperiods. These characteristics make it difficult to locate vernal pool habitats in the landscape during much of the year, and no efficient method exists for predicting their occurrence. A logistic regression procedure was used to identify large-scale variables that influence the presence of a potential vernal pool, including surficial geology, land use and land cover, soil classification, topography, precipitation, and surficial hydrologic features. The model was validated with locations of field-verified vernal pools. The model demonstrated that the probability of potential vernal pool occurrence is positively related to slope, negatively related to till/bedrock surficial geology, and negatively related to the proportion of cropland, urban/commercial, and high density residential development in the landscape. The relationship between vernal pool occurrence and large-scale variables suggests that these habitats do not occur at random in the landscape, and thus, protection in situ should be considered.

  13. Analytical measurement of discrete hydrogen sulfide pools in biological specimens.

    PubMed

    Shen, Xinggui; Peter, Elvis A; Bir, Shyamal; Wang, Rui; Kevil, Christopher G

    Hydrogen sulfide (H₂S) is a ubiquitous gaseous signaling molecule that plays a vital role in numerous cellular functions and has become the focus of many research endeavors, including pharmacotherapeutic manipulation. Among the challenges facing the field is the accurate measurement of biologically active H₂S. We have recently reported that the typically used methylene blue method and its associated results are invalid and do not measure bona fide H₂S. The complexity of analytical H₂S measurement reflects the fact that hydrogen sulfide is a volatile gas and exists in the body in various forms, including a free form, an acid-labile pool, and bound as sulfane sulfur. Here we describe a new protocol to discretely measure specific H₂S pools using the monobromobimane method coupled with RP-HPLC. This new protocol involves selective liberation, trapping, and derivatization of H₂S. Acid-labile H₂S is released by incubating the sample in an acidic solution (pH 2.6) of 100 mM phosphate buffer with 0.1mM diethylenetriaminepentaacetic acid (DTPA), in an enclosed system to contain volatilized H₂S. Volatilized H₂S is then trapped in 100 mM Tris-HCl (pH 9.5, 0.1 mM DTPA) and then reacted with excess monobromobimane. In a separate aliquot, the contribution of the bound sulfane sulfur pool was measured by incubating the sample with 1 mM TCEP (tris(2-carboxyethyl)phosphine hydrochloride), a reducing agent, to reduce disulfide bonds, in 100 mM phosphate buffer (pH 2.6, 0.1 mM DTPA), and H₂S measurement was performed in a manner analogous to the one described above. The acid-labile pool was determined by subtracting the free hydrogen sulfide value from the value obtained by the acid-liberation protocol. The bound sulfane sulfur pool was determined by subtracting the H₂S measurement from the acid-liberation protocol alone compared to that of TCEP plus acidic conditions. In summary, our new method allows very sensitive and accurate measurement of the three primary

  14. Variability of chlorination by-product occurrence in water of indoor and outdoor swimming pools.

    PubMed

    Simard, Sabrina; Tardif, Robert; Rodriguez, Manuel J

    2013-04-01

    Swimming is one of the most popular aquatic activities. Just like natural water, public pool water may contain microbiological and chemical contaminants. The purpose of this study was to study the presence of chemical contaminants in swimming pools, in particular the presence of disinfection by-products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs) and inorganic chloramines (CAMi). Fifty-four outdoor and indoor swimming pools were investigated over a period of one year (monthly or bi-weekly sampling, according to the type of pool) for the occurrence of DBPs. The results showed that DBP levels in swimming pools were greater than DBP levels found in drinking water, especially for HAAs. Measured concentrations of THMs (97.9 vs 63.7 μg/L in average) and HAAs (807.6 vs 412.9 μg/L in average) were higher in outdoor pools, whereas measured concentrations of CAMi (0.1 vs 0.8 mg/L in average) were higher in indoor pools. Moreover, outdoor pools with heated water contained more DBPs than unheated pools. Finally, there was significant variability in tTHM, HAA9 and CAMi levels in pools supplied by the same municipal drinking water network, suggesting that individual pool characteristics (number of swimmers) and management strategies play a major role in DBP formation.

  15. Investigation of the biological and anti-cancer properties of ellagic acid-encapsulated nano-sized metalla-cages.

    PubMed

    Dubey, Abhishek; Park, Dae Won; Kwon, Jung Eun; Jeong, Yong Joon; Kim, Taegeun; Kim, Inhye; Kang, Se Chan; Chi, Ki-Whan

    2015-01-01

    Three new large hexanuclear metalla-prisms 9-11 incorporating 1,3, 5-tris(pyridin-4-ylethynyl)benzene (tpeb) 4 and one of the dinuclear arene ruthenium clips [Ru2(p-iPrC6H4Me)2(OO∩OO)][CF3SO3]2 (OO∩OO =2,5-dioxydo-1,4-benzoquinonato [dobq] 1, 5,8-dihydroxy-1,4-naphthaquinonato (donq) 2, and 6,11-dihydroxy-5,12-naphthacenedionato [dotq] 3), which encapsulate the guest molecule ellagic acid (2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione, 5) were prepared. All complexes were isolated as triflate salts in good yields and were fully characterized by (1)H NMR spectroscopy and electrospray ionization mass spectrometry. The photophysical properties of these metalla-prisms were also investigated. Compounds 9 and 10 showed potent antioxidant activity, but 10 had the superior ORACPE value (1.30 ± 0.020). Ellagic acid (5) and compound 11 showed weaker activity than that of Trolox. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the metalla-prism compounds exhibit anticancer properties in vitro. Compound 10 inhibited the growth of all cancer cell lines at micromolar concentrations, with the highest cytotoxicity observed against A549 human lung cancer cells (IC50 =25.9 μM). However, these compounds had a lower anti-cancer activity than that of doxorubicin. In a tumoricidal assay, ellagic acid (5) and compound 10 induced cytotoxicity in tumor cells, while doxorubicin did not. While free ellagic acid had no effect on the granulocyte-colony stimulating factor and regulated on activation normal T cell expressed and secreted protein, the encapsulated metalla-prism 10 stimulated granulocyte-colony stimulating factor and reduced regulated on activation normal T cell expressed and secreted protein expression in the RAW264.7 macrophage line. Our results show that ellagic acid encapsulated in metalla-prisms inhibited cancer cells via the modulation of mRNA induction and protein expression levels of the granulocyte-colony stimulating

  16. Investigation of the biological and anti-cancer properties of ellagic acid-encapsulated nano-sized metalla-cages

    PubMed Central

    Dubey, Abhishek; Park, Dae Won; Kwon, Jung Eun; Jeong, Yong Joon; Kim, Taegeun; Kim, Inhye; Kang, Se Chan; Chi, Ki-Whan

    2015-01-01

    Three new large hexanuclear metalla-prisms 9–11 incorporating 1,3, 5-tris(pyridin-4-ylethynyl)benzene (tpeb) 4 and one of the dinuclear arene ruthenium clips [Ru2(p-iPrC6H4Me)2(OO∩OO)][CF3SO3]2 (OO∩OO =2,5-dioxydo-1,4-benzoquinonato [dobq] 1, 5,8-dihydroxy-1,4-naphthaquinonato (donq) 2, and 6,11-dihydroxy-5,12-naphthacenedionato [dotq] 3), which encapsulate the guest molecule ellagic acid (2,3,7,8-tetrahydroxy-chromeno[5,4,3-cde]chromene-5,10-dione, 5) were prepared. All complexes were isolated as triflate salts in good yields and were fully characterized by 1H NMR spectroscopy and electrospray ionization mass spectrometry. The photophysical properties of these metalla-prisms were also investigated. Compounds 9 and 10 showed potent antioxidant activity, but 10 had the superior ORACPE value (1.30±0.020). Ellagic acid (5) and compound 11 showed weaker activity than that of Trolox. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the metalla-prism compounds exhibit anticancer properties in vitro. Compound 10 inhibited the growth of all cancer cell lines at micromolar concentrations, with the highest cytotoxicity observed against A549 human lung cancer cells (IC50 =25.9 μM). However, these compounds had a lower anti-cancer activity than that of doxorubicin. In a tumoricidal assay, ellagic acid (5) and compound 10 induced cytotoxicity in tumor cells, while doxorubicin did not. While free ellagic acid had no effect on the granulocyte-colony stimulating factor and regulated on activation normal T cell expressed and secreted protein, the encapsulated metalla-prism 10 stimulated granulocyte-colony stimulating factor and reduced regulated on activation normal T cell expressed and secreted protein expression in the RAW264.7 macrophage line. Our results show that ellagic acid encapsulated in metalla-prisms inhibited cancer cells via the modulation of mRNA induction and protein expression levels of the granulocyte-colony stimulating

  17. Method of measuring a liquid pool volume

    DOEpatents

    Garcia, Gabe V.; Carlson, Nancy M.; Donaldson, Alan D.

    1991-01-01

    A method of measuring a molten metal liquid pool volume and in particular molten titanium liquid pools, including the steps of (a) generating an ultrasonic wave at the surface of the molten metal liquid pool, (b) shining a light on the surface of a molten metal liquid pool, (c) detecting a change in the frequency of light, (d) detecting an ultrasonic wave echo at the surface of the molten metal liquid pool, and (e) computing the volume of the molten metal liquid.

  18. Total volatile fatty acid concentrations are unreliable estimators of treatment effects on ruminal fermentation in vivo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volatile fatty acid concentrations ([VFA], mM) have long been used to assess impact of dietary treatments on ruminal fermentation in vivo. However, discrepancies in statistical results between VFA and VFA pool size (VFAmol), possibly related to ruminal digesta liquid amount (LIQ, kg), suggest issues...

  19. Identification of homogeneous and heterogeneous variables in pooled cohort studies.

    PubMed

    Cheng, Xin; Lu, Wenbin; Liu, Mengling

    2015-06-01

    Pooled analyses integrate data from multiple studies and achieve a larger sample size for enhanced statistical power. When heterogeneity exists in variables' effects on the outcome across studies, the simple pooling strategy fails to present a fair and complete picture of the effects of heterogeneous variables. Thus, it is important to investigate the homogeneous and heterogeneous structure of variables in pooled studies. In this article, we consider the pooled cohort studies with time-to-event outcomes and propose a penalized Cox partial likelihood approach with adaptively weighted composite penalties on variables' homogeneous and heterogeneous effects. We show that our method can characterize the variables as having heterogeneous, homogeneous, or null effects, and estimate non-zero effects. The results are readily extended to high-dimensional applications where the number of parameters is larger than the sample size. The proposed selection and estimation procedure can be implemented using the iterative shooting algorithm. We conduct extensive numerical studies to evaluate the performance of our proposed method and demonstrate it using a pooled analysis of gene expression in patients with ovarian cancer. PMID:25732747

  20. Molecular sizes of amino acid transporters in the luminal membrane from the kidney cortex, estimated by the radiation-inactivation method.

    PubMed Central

    Béliveau, R; Demeule, M; Jetté, M; Potier, M

    1990-01-01

    Renal brush-border membrane vesicles from rat kidney cortex were irradiated in frozen state with a gamma-radiation source. Initial rates of influx into these vesicles were estimated for substrates such as L-glutamic acid, L-alanine, L-proline and L-leucine to establish the molecular sizes of their carriers. Transport was measured in initial-rate conditions to avoid artifacts arising from a decrease in the driving force caused by a modification of membrane permeability. Initial rates of Na(+)-independent uptakes for those four substrates appeared unaffected in the dose range used (0-6 Mrad), indicating that the passive permeability of the membrane towards these substrates was unaffected. However, at higher doses of irradiation the Na+ influx and the intravesicular volume evaluated by the uptake of glucose at equilibrium were altered by radiation. Thus Na(+)-dependent influx values were corrected for volume changes, and the corrected values were used to compute radiation-inactivation sizes of the transport systems. Their respective values for L-glutamic acid, L-proline, L-leucine and L-alanine carriers were 250, 224, 293 and 274 kDa. The presence of the free-radicals scavenger benzoic acid in the frozen samples during irradiation did not affect the uptake of glucose, phosphate and alkaline phosphatase activity. These results indicate that freezing samples in a cryoprotective medium was enough to prevent secondary inactivation of transporters by free radicals. Uptakes of beta-alanine and L-lysine were much less affected by radiation. The radiation-inactivation size of the Na(+)-dependent beta-alanine carrier was 127 kDa and that of the L-lysine carrier was 90 kDa. PMID:1971509

  1. Using self-consistent Gibbs free energy surfaces to calculate size distributions of neutral and charged clusters for the sulfuric acid-water binary system

    NASA Astrophysics Data System (ADS)

    Smith, J. A.; Froyd, K. D.; Toon, O. B.

    2012-12-01

    We construct tables of reaction enthalpies and entropies for the association reactions involving sulfuric acid vapor, water vapor, and the bisulfate ion. These tables are created from experimental measurements and quantum chemical calculations for molecular clusters and a classical thermodynamic model for larger clusters. These initial tables are not thermodynamically consistent. For example, the Gibbs free energy of associating a cluster consisting of one acid molecule and two water molecules depends on the order in which the cluster was assembled: add two waters and then the acid or add an acid and a water and then the second water. We adjust the values within the tables using the method of Lagrange multipliers to minimize the adjustments and produce self-consistent Gibbs free energy surfaces for the neutral clusters and the charged clusters. With the self-consistent Gibbs free energy surfaces, we calculate size distributions of neutral and charged clusters for a variety of atmospheric conditions. Depending on the conditions, nucleation can be dominated by growth along the neutral channel or growth along the ion channel followed by ion-ion recombination.

  2. Dicarboxylic acids, oxoacids, benzoic acid, α-dicarbonyls, WSOC, OC, and ions in spring aerosols from Okinawa Island in the western North Pacific Rim: size distributions and formation processes

    NASA Astrophysics Data System (ADS)

    Deshmukh, Dhananjay K.; Kawamura, Kimitaka; Lazaar, Manuel; Kunwar, Bhagawati; Boreddy, Suresh K. R.

    2016-04-01

    Size-segregated aerosols (nine stages from < 0.43 to > 11.3 µm in diameter) were collected at Cape Hedo, Okinawa, in spring 2008 and analyzed for water-soluble diacids (C2-C12), ω-oxoacids (ωC2-ωC9), pyruvic acid, benzoic acid, and α-dicarbonyls (C2-C3) as well as water-soluble organic carbon (WSOC), organic carbon (OC), and major ions (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-, SO42-, and MSA-). In all the size-segregated aerosols, oxalic acid (C2) was found to be the most abundant species, followed by malonic and succinic acids, whereas glyoxylic acid (ωC2) was the dominant oxoacid and glyoxal (Gly) was more abundant than methylglyoxal. Diacids (C2-C5), ωC2, and Gly as well as WSOC and OC peaked at fine mode (0.65-1.1 µm) whereas azelaic (C9) and 9-oxononanoic (ωC9) acids peaked at coarse mode (3.3-4.7 µm). Sulfate and ammonium were enriched in fine mode, whereas sodium and chloride were in coarse mode. Strong correlations of C2-C5 diacids, ωC2 and Gly with sulfate were observed in fine mode (r = 0.86-0.99), indicating a commonality in their secondary formation. Their significant correlations with liquid water content in fine mode (r = 0.82-0.95) further suggest an importance of the aqueous-phase production in Okinawa aerosols. They may also have been directly emitted from biomass burning in fine mode as supported by strong correlations with potassium (r = 0.85-0.96), which is a tracer of biomass burning. Bimodal size distributions of longer-chain diacid (C9) and oxoacid (ωC9) with a major peak in the coarse mode suggest that they were emitted from the sea surface microlayers and/or produced by heterogeneous oxidation of biogenic unsaturated fatty acids on sea salt particles.

  3. Intestinal transport and metabolism of bile acids

    PubMed Central

    Dawson, Paul A.; Karpen, Saul J.

    2015-01-01

    In addition to their classical roles as detergents to aid in the process of digestion, bile acids have been identified as important signaling molecules that function through various nuclear and G protein-coupled receptors to regulate a myriad of cellular and molecular functions across both metabolic and nonmetabolic pathways. Signaling via these pathways will vary depending on the tissue and the concentration and chemical structure of the bile acid species. Important determinants of the size and composition of the bile acid pool are their efficient enterohepatic recirculation, their host and microbial metabolism, and the homeostatic feedback mechanisms connecting hepatocytes, enterocytes, and the luminal microbiota. This review focuses on the mammalian intestine, discussing the physiology of bile acid transport, the metabolism of bile acids in the gut, and new developments in our understanding of how intestinal metabolism, particularly by the gut microbiota, affects bile acid signaling. PMID:25210150

  4. Linking soil organic carbon pools with measured fractions

    NASA Astrophysics Data System (ADS)

    Herbst, M.; Welp, G.; Amelung, W.; Vereecken, H.

    2011-12-01

    Soil organic carbon (SOC) pools play an important role for the understanding and the predictive modelling of heterotrophic respiration. One of the major issues concerning model carbon pools is their purely conceptual definition. They are just defined by a turnover rate. Despite some attempts to link the conceptual model pools to measurable SOC fractions, this challenge basically remains unsolved. In this study we introduce an empirical approach to link the model pools of RothC with measured particulate organic matter fractions and an inert carbon fraction. For 63 topsoil samples from arable fields a mid-infrared spectroscopic approach was applied to determine the carbon contents in three particle-size fractions (POM1: 2000-250 μm, POM2: 250-53 μm and POM3: 53-20 μm) and a black carbon fraction. To provide the model pools for the 63 sampling sites RothC was run into equilibrium based on site-specific soil properties and meteorological data ranging from 1961 to present. It was possible to prove a link between soil organic matter fractions and pools of RothC. The coefficient of correlation between fPOM (POM1+POM2) and the resistant plant material (RPM) pool was 0.73. However, establishing multiple linear regressions based on all measured fractions instead of using just the fraction between 2000 and 53 μm significantly improved the prediction of the RPM pool. The resultant adjusted coefficient of determination using all fractions to predict RPM was 0.94. A stepwise regression algorithm based on the Akaike information criterion retained all measured fractions in the regression, pointing to the relevance of all fractions. The same was observed when linking the humic fraction of RothC (HUM) to the measured humic fractions, which were calculated as the difference between TOC and the sum of particulate and black carbon. The adjusted coefficient of determination was 0.84. Using again all measured fractions as explanatory variables for HUM increased the coefficient of

  5. Linking soil organic carbon pools with measured fractions

    NASA Astrophysics Data System (ADS)

    Herbst, M.; Welp, G.; Amelung, W.; Weihermueller, L.; Vereecken, H.

    2012-04-01

    Soil organic carbon (SOC) pools play an important role for the understanding and the predictive modelling of heterotrophic respiration. One of the major issues concerning model carbon pools is their purely conceptual definition. They are just defined by a turnover rate. Despite some attempts to link the conceptual model pools to measurable SOC fractions, this challenge basically remains unsolved. In this study we introduce an empirical approach to link the model pools of RothC with measured particulate organic matter fractions and an inert carbon fraction. For 63 topsoil samples from arable fields a mid-infrared spectroscopic approach was applied to determine the carbon contents in three particle-size fractions (POM1: 2000-250 μm, POM2: 250-53 μm and POM3: 53-20 μm) and a black carbon fraction. To provide the model pools for the 63 sampling sites RothC was run into equilibrium based on site-specific soil properties and meteorological data ranging from 1961 to present. It was possible to prove a link between soil organic matter fractions and pools of RothC. The coefficient of correlation between fPOM (POM1+POM2) and the resistant plant material (RPM) pool was 0.73. However, establishing multiple linear regressions based on all measured fractions instead of using just the fraction between 2000 and 53 μm significantly improved the prediction of the RPM pool. The resultant adjusted coefficient of determination using all fractions to predict RPM was 0.94. A stepwise regression algorithm based on the Akaike information criterion retained all measured fractions in the regression, pointing to the relevance of all fractions. The same was observed when linking the humic fraction of RothC (HUM) to the measured humic fractions, which were calculated as the difference between TOC and the sum of particulate and black carbon. The adjusted R2 was 0.84. Using again all measured fractions as explanatory variables for HUM increased the R2 to 0.99. From these observations we

  6. Flame spread across liquid pools

    NASA Technical Reports Server (NTRS)

    Ross, Howard; Miller, Fletcher; Schiller, David; Sirignano, William A.

    1993-01-01

    For flame spread over liquid fuel pools, the existing literature suggests three gravitational influences: (1) liquid phase buoyant convection, delaying ignition and assisting flame spread; (2) hydrostatic pressure variation, due to variation in the liquid pool height caused by thermocapillary-induced convection; and (3) gas-phase buoyant convection in the opposite direction to the liquid phase motion. No current model accounts for all three influences. In fact, prior to this work, there was no ability to determine whether ignition delay times and flame spread rates would be greater or lesser in low gravity. Flame spread over liquid fuel pools is most commonly characterized by the relationship of the initial pool temperature to the fuel's idealized flash point temperature, with four or five separate characteristic regimes having been identified. In the uniform spread regime, control has been attributed to: (1) gas-phase conduction and radiation; (2) gas-phase conduction only; (3) gas-phase convection and liquid conduction, and most recently (4) liquid convection ahead of the flame. Suggestions were made that the liquid convection was owed to both vuoyancy and thermocapillarity. Of special interest to this work is the determination of whether, and under what conditions, pulsating spread can and will occur in microgravity in the absence of buoyant flows in both phases. The approach we have taken to resolving the importance of buoyancy for these flames is: (1) normal gravity experiments and advanced diagnostics; (2) microgravity experiments; and (3) numerical modelling at arbitrary gravitational level.

  7. Effect of particle size and heat treatment of soybean meal on standardized ileal digestibility of amino acids in growing pigs.

    PubMed

    Messerschmidt, U; Eklund, M; Rist, V T S; Rosenfelder, P; Spindler, H K; Htoo, J K; Mosenthin, R

    2012-12-01

    A study with growing barrows was conducted to evaluate of variations in particle size and degree of heat treatment during processing on standardized ileal digestibility (SID) of AA in soybean (Glycine max) meal (SBM). A commercial SBM batch was visually identified as being overtoasted due to its brownish color and was separated into small and large particles using a 1-mm sieve. In addition, 3 SBM were produced from 1 batch of soybean and exposed to different processing conditions (temperature and direct steam contact) referred to as mild (105°C; 34 min), medium (115°C; 45 min), and strong (139°C; 7 min). In total, 5 SBM-corn (Zea mays) starch-based diets were formulated to contain SBM as the sole protein source. This experiment was conducted according to a 6 × 6 Latin square design using 6 barrows (23 kg initial BW) fitted with a T-cannula at the distal ileum. With increasing particle size, SID of His and some dispensable AA increased (P < 0.05). Lower SID values in small compared to large SBM particles indicate more pronounced heat damage possibly due to increased surface area. The SID of CP and AA was lowest in the mild, intermediate in the strong, and highest in the medium toasted SBM (P < 0.001). These differences in SID are reflected in varying contents of trypsin inhibitors, Lys, reactive Lys, and NDF. In conclusion, both differences in particles size and variations in thermal processing conditions of SBM may affect SID of CP and AA.

  8. Separation of oligonucleotides of identical size, but different base composition, by free zone capillary electrophoresis in strongly acidic, isoelectric buffers.

    PubMed

    Perego, M; Gelfi, C; Stoyanov, A V; Righetti, P G

    1997-12-01

    A novel method for analyzing oligonucleotides of the same length, but bearing a single base substitution, is reported, based on free zone capillary electrophoresis (CZE) under rather acidic pH values. For this purpose, a set of four 18-mers of fairly random base composition has been synthesized, bearing, in nucleotide 9, the following bases: T, C, G or A. Theoretical predictions, based on titration curves of single free nucleotides, allowed us to predict that the simultaneous separation of a mixture of all four oligonucleotides could be possible in a pH 3-4 window. In fact, electrophoresis at pH 5.7 gave a single, asymmetric peak, whereas CZE at pH 4.8 could resolve three out of four species (the T9 and G9 oligonucleotides co-migrating into a single zone). A unique separation power could be obtained at pH 3.3 in a buffer comprising an amphoteric species (isoelectric iminodiacetic acid, IDA) and 7 M urea. Although IDA exhibited a pI of 2.23 (for a 100 mM solution), the addition of 7 M urea (necessary to denature the oligonucleotides) raised the apparent pH of the solution to 3.3. PMID:9504830

  9. The 1980-81 AFE Pool: The End of an Era.

    ERIC Educational Resources Information Center

    Knight, Peter

    1981-01-01

    The Advanced Further Education (AFE) Pool was conceived in Britain in the 1950s to distribute public funds for higher education. The 1980-81 pool broke with tradition by having a fixed amount to be apportioned by local authorities rather than having a size determined by institutional needs. The change is seen as fundamentally political. (SE)

  10. ESTIMATING THE TERRESTIAL CARBON POOLS OF THE FORMER SOVIET UNION, CONTERMINOUS U.S., AND BRAZIL

    EPA Science Inventory

    Terrestrial-carbon (C) pool sizes are of interest in relation to quantifying current sources and sinks of C, and evaluating the possibilities for future C sequestration or release by the biosphere. In this study, the C pools in the terrestrial ecosystems of the former Soviet Unio...

  11. DROWNING IN DISINFECTION BY-PRODUCTS? SWIMMING POOL WATER QUALITY RECONSIDERED.

    EPA Science Inventory

    The development of treated water for swimming pools has made swimming a year ¬round activity, widely enjoyed for leisure as well as exercise. Swimming pools can be found in different kinds and sizes in public areas, hotels and spas, or at private homes. In Germany ~250-300 millio...

  12. Interactions between pool geometry and hydraulics

    USGS Publications Warehouse

    Thompson, D.M.; Nelson, J.M.; Wohl, E.E.

    1998-01-01

    An experimental and computational research approach was used to determine interactions between pool geometry and hydraulics. A 20-m-long, 1.8-m-wide flume was used to investigate the effect of four different geometric aspects of pool shape on flow velocity. Plywood sections were used to systematically alter constriction width, pool depth, pool length, and pool exit-slope gradient, each at two separate levels. Using the resulting 16 unique geometries with measured pool velocities in four-way factorial analyses produced an empirical assessment of the role of the four geometric aspects on the pool flow patterns and hence the stability of the pool. To complement the conclusions of these analyses, a two-dimensional computational flow model was used to investigate the relationships between pool geometry and flow patterns over a wider range of conditions. Both experimental and computational results show that constriction and depth effects dominate in the jet section of the pool and that pool length exhibits an increasing effect within the recirculating-eddy system. The pool exit slope appears to force flow reattachment. Pool length controls recirculating-eddy length and vena contracta strength. In turn, the vena contracta and recirculating eddy control velocities throughout the pool.

  13. Water-soluble ions species of size-resolved aerosols: Implications for the atmospheric acidity in São Paulo megacity, Brazil

    NASA Astrophysics Data System (ADS)

    Vieira-Filho, Marcelo; Pedrotti, Jairo J.; Fornaro, Adalgiza

    2016-11-01

    Over the last decade, an increase of ammonium salts in atmospheric deposition has been reported worldwide, especially in megacities. The present study aims to give a better comprehension analysis about particulate matter acidity in São Paulo megacity (MASP), Brazil. Size-resolved aerosols were sampled in MASP, during 2012 winter, showing a bimodal mass concentration distribution, with sulfate concentration exceeding 3.40 μg m- 3, which accounted for over 25% of PM0.56 mass. Regarding the relative distribution of ionic species, 90% of NH4+ levels, were restricted to smaller than 1 μm diameter range. The average neutralization index for PM < 1 μm was 0.62, which indicated an ammonia-limiting atmosphere due to partial neutralization of atmospheric acids. Particles of the accumulation mode presented more acid behavior than other aerosol fractions, with pH value as low as 4.15 in PM0.56. The total neutralization index registered the lowest value for PM0.56, but it did not respond promptly to aerosol variations as the E-AIM model predictions. The highest discrepancies between the acidity proxies occurred in the smaller fractions of particulate matter, especially in the after-filter (AF) stage (diameter < 0.020 μm). In addition, AF stage had the highest contribution to PM total mass, about 14% for all the stages analyzed. Such contribution indicates that acidity in ultrafine particles are still mixed for the MASP and need further investigation.

  14. Using DNA pools for genotyping trios.

    PubMed

    Beckman, Kenneth B; Abel, Kenneth J; Braun, Andreas; Halperin, Eran

    2006-01-01

    The genotyping of mother-father-child trios is a very useful tool in disease association studies, as trios eliminate population stratification effects and increase the accuracy of haplotype inference. Unfortunately, the use of trios for association studies may reduce power, since it requires the genotyping of three individuals where only four independent haplotypes are involved. We describe here a method for genotyping a trio using two DNA pools, thus reducing the cost of genotyping trios to that of genotyping two individuals. Furthermore, we present extensions to the method that exploit the linkage disequilibrium structure to compensate for missing data and genotyping errors. We evaluated our method on trios from CEPH pedigree 66 of the Coriell Institute. We demonstrate that the error rates in the genotype calls of the proposed protocol are comparable to those of standard genotyping techniques, although the cost is reduced considerably. The approach described is generic and it can be applied to any genotyping platform that achieves a reasonable precision of allele frequency estimates from pools of two individuals. Using this approach, future trio-based association studies may be able to increase the sample size by 50% for the same cost and thereby increase the power to detect associations.

  15. WATER INGESTION DURING SWIMMING ACTIVITIES IN A POOL: A PILOT STUDY

    EPA Science Inventory

    Chloroisocyanurates are commonly added to outdoor swimming pools to stabilize chlorine disinfectants. The chloroisocyanurates decompose slowly to release chlorine and cyanuric acid. Studies conducted to determine if the chloroisocyanurates might be toxic to swimmers showed that...

  16. Phase- and size-controllable synthesis of hexagonal upconversion rare-earth fluoride nanocrystals through an oleic acid/ionic liquid two-phase system.

    PubMed

    He, Meng; Huang, Peng; Zhang, Chunlei; Ma, Jiebing; He, Rong; Cui, Daxiang

    2012-05-01

    Herein, we introduce a facile, user- and environmentally friendly (n-octanol-induced) oleic acid (OA)/ionic liquid (IL) two-phase system for the phase- and size-controllable synthesis of water-soluble hexagonal rare earth (RE = La, Gd, and Y) fluoride nanocrystals with uniform morphologies (mainly spheres and elongated particles) and small sizes (<50 nm). The unique role of the IL 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF(6)) and n-octanol in modulating the phase structure and particle size are discussed in detail. More importantly, the mechanism of the (n-octanol-induced) OA/IL two-phase system, the formation of the RE fluoride nanocrystals, and the distinctive size- and morphology-controlling capacity of the system are presented. BmimPF(6) is versatile in term of crystal-phase manipulation, size and shape maintenance, and providing water solubility in a one-step reaction. The luminescent properties of Er(3+)-, Ho(3+)-, and Tm(3+)-doped LaF(3), NaGdF(4), and NaYF(4) nanocrystals were also studied. It is worth noting that the as-prepared products can be directly dispersed in water due to the hydrophilic property of Bmim(+) (cationic part of the IL) as a capping agent. This advantageous feature has made the IL-capped products favorable in facile surface modifications, such as the classic Stober method. Finally, the cytotoxicity evaluation of NaYF(4):Yb,Er nanocrystals before and after silica coating was conducted for further biological applications.

  17. Implications of spectroscopic and thermo-spectroscopic approaches for pool parameterization of SOM models

    NASA Astrophysics Data System (ADS)

    Demyan, Scott; Marohn, Carsten; Rasche, Frank; Mirzaeitalarposhti, Reza; Nkwain Funkuin, Yvonne; Shahbaz Ali, Rana; Högy, Petra; Ingwersen, Joachim; Wizemann, Hans-Dieter; Müller, Torsten; Cadisch, Georg

    2014-05-01

    While soil organic matter (SOM) models such as Century or Daisy have been applied in a variety of environments and land uses to simulate measured SOM dynamics, the issue of how to parameterize the compartments or pools of these models is not straight forward. Default pool sizes are not suited for all soils, equilibrium model runs of thousands of years may not well approximate the system if previous land-uses are not known or not at equilibrium. Measured SOM fractions have been used to parameterize the pool sizes, but the intermediate and passive pool sizes have been difficult to relate to measureable fractions. This study examined the use of size/density fractionation (SOM fractions), mid-infrared spectroscopy (MIRS), or thermally evolved gas analysis (EGA) derived pools as compared to a long-term model run (Equilibrium) to parameterize model pools of the Century and Daisy SOM models of two arable soils in Southwest Germany. Initial pool sizes were set via the various methods and measured soil organic carbon (SOC) and crop parameters used for the beginning of the model run. Results were compared with measured data of field soil carbon dioxide (CO2) fluxes, microbial biomass (SMB), and SOC after several growing seasons. It was found that the different initialization methods resulted in a wide range of pool sizes, with the Equilibrium method the smallest fast turn-over pool allocation and the MIRS method with the largest. The EGA, SOM fractions and MIRS approaches resulted in better modeled CO2 flux as compared to the Equilibrium method. The active pool size allocation had an effect on short-term dynamics within the first modeling year, but diminished thereafter. During a twenty-year simulation the size of slow turn-over resulted in very different final SOC amounts, showing the importance of proper initialization of the intermediate to passive pools for future predictions of SOC. This study demonstrated several approaches and possible implications of using these

  18. A revised velocity-reversal and sediment-sorting model for a high-gradient, pool-riffle stream

    USGS Publications Warehouse

    Thompson, D.M.; Wohl, E.E.; Jarrett, R.D.

    1996-01-01

    Sediment-sorting processes related to varying channel-bed morphology were investigated from April to November 1993 along a 1-km pool-riffle and step-pool reach of North Saint Vrain Creek, a small mountain stream in the Rocky Mountains of northern Colorado. Measured cross-sectional areas of flow were used to suggest higher velocities in pools than in riffles at high flow. Three hundred and sixteen tracer particles, ranging in size from 16 mm to 256 mm, were placed in two separate pool-riffle-pool sequences and used to assess sediment-sorting patterns and sediment-transport competence variations. Tracer-particle depositional evidence indicated higher sediment-transport competence in pools than in riffles at high flow. Pool-riffle sediment sorting may be created by velocity reversals, and more localized sorting results from gravitational forces along the upstream sloping portion of the channel bed located at the downstream end of pools.

  19. Effect of ration size on fillet fatty acid composition, phospholipid allostasis and mRNA expression patterns of lipid regulatory genes in gilthead sea bream (Sparus aurata).

    PubMed

    Benedito-Palos, Laura; Calduch-Giner, Josep A; Ballester-Lozano, Gabriel F; Pérez-Sánchez, Jaume

    2013-04-14

    The effect of ration size on muscle fatty acid (FA) composition and mRNA expression levels of key regulatory enzymes of lipid and lipoprotein metabolism have been addressed in juveniles of gilthead sea bream fed a practical diet over the course of an 11-week trial. The experimental setup included three feeding levels: (i) full ration until visual satiety, (ii) 70 % of satiation and (iii) 70 % of satiation with the last 2 weeks at the maintenance ration. Feed restriction reduced lipid content of whole body by 30 % and that of fillet by 50 %. In this scenario, the FA composition of fillet TAG was not altered by ration size, whereas that of phospholipids was largely modified with a higher retention of arachidonic acid and DHA. The mRNA transcript levels of lysophosphatidylcholine acyltransferases, phosphatidylethanolamine N-methyltransferase and FA desaturase 2 were not regulated by ration size in the present experimental model. In contrast, mRNA levels of stearoyl-CoA desaturases were markedly down-regulated by feed restriction. An opposite trend was found for a muscle-specific lipoprotein lipase, which is exclusive of fish lineage. Several upstream regulatory transcriptions were also assessed, although nutritionally mediated changes in mRNA transcripts were almost reduced to PPARα and β, which might act in a counter-regulatory way on lipolysis and lipogenic pathways. This gene expression pattern contributes to the construction of a panel of biomarkers to direct marine fish production towards muscle lean phenotypes with increased retentions of long-chain PUFA.

  20. A high load of non-neutral amino-acid polymorphisms explains high protein diversity despite moderate effective population size in a marine bivalve with sweepstakes reproduction.

    PubMed

    Harrang, Estelle; Lapègue, Sylvie; Morga, Benjamin; Bierne, Nicolas

    2013-02-01

    Marine bivalves show among the greatest allozyme diversity ever reported in Eukaryotes, putting them historically at the heart of the neutralist-selectionist controversy on the maintenance of genetic variation. Although it is now acknowledged that this high diversity is most probably a simple consequence of a large population size, convincing support for this explanation would require a rigorous assessment of the silent nucleotide diversity in natural populations of marine bivalves, which has not yet been done. This study investigated DNA sequence polymorphism in a set of 37 nuclear loci in wild samples of the flat oyster Ostrea edulis. Silent diversity was found to be only moderate (0.7%), and there was no departure from demographic equilibrium under the Wright-Fisher model, suggesting that the effective population size might not be as large as might have been expected. In accordance with allozyme heterozygosity, nonsynonymous diversity was comparatively very high (0.3%), so that the nonsynonymous to silent diversity ratio reached a value rarely observed in any other organism. We estimated that one-quarter of amino acid-changing mutations behave as neutral in O. edulis, and as many as one-third are sufficiently weakly selected to segregate at low frequency in the polymorphism. Finally, we inferred that one oyster is expected to carry more than 4800 non-neutral alleles (or 4.2 cM(-1)). We conclude that a high load of segregating non-neutral amino-acid polymorphisms contributes to high protein diversity in O. edulis. The high fecundity of marine bivalves together with an unpredictable and highly variable success of reproduction and recruitment (sweepstakes reproduction) might produce a greater decoupling between Ne and N than in other organisms with lower fecundities, and we suggest this could explain why a higher segregating load could be maintained for a given silent mutation effective size.

  1. A High Load of Non-neutral Amino-Acid Polymorphisms Explains High Protein Diversity Despite Moderate Effective Population Size in a Marine Bivalve With Sweepstakes Reproduction

    PubMed Central

    Harrang, Estelle; Lapègue, Sylvie; Morga, Benjamin; Bierne, Nicolas

    2013-01-01

    Marine bivalves show among the greatest allozyme diversity ever reported in Eukaryotes, putting them historically at the heart of the neutralist−selectionist controversy on the maintenance of genetic variation. Although it is now acknowledged that this high diversity is most probably a simple consequence of a large population size, convincing support for this explanation would require a rigorous assessment of the silent nucleotide diversity in natural populations of marine bivalves, which has not yet been done. This study investigated DNA sequence polymorphism in a set of 37 nuclear loci in wild samples of the flat oyster Ostrea edulis. Silent diversity was found to be only moderate (0.7%), and there was no departure from demographic equilibrium under the Wright-Fisher model, suggesting that the effective population size might not be as large as might have been expected. In accordance with allozyme heterozygosity, nonsynonymous diversity was comparatively very high (0.3%), so that the nonsynonymous to silent diversity ratio reached a value rarely observed in any other organism. We estimated that one-quarter of amino acid-changing mutations behave as neutral in O. edulis, and as many as one-third are sufficiently weakly selected to segregate at low frequency in the polymorphism. Finally, we inferred that one oyster is expected to carry more than 4800 non-neutral alleles (or 4.2 cM−1). We conclude that a high load of segregating non-neutral amino-acid polymorphisms contributes to high protein diversity in O. edulis. The high fecundity of marine bivalves together with an unpredictable and highly variable success of reproduction and recruitment (sweepstakes reproduction) might produce a greater decoupling between Ne and N than in other organisms with lower fecundities, and we suggest this could explain why a higher segregating load could be maintained for a given silent mutation effective size. PMID:23390609

  2. Effect of ration size on fillet fatty acid composition, phospholipid allostasis and mRNA expression patterns of lipid regulatory genes in gilthead sea bream (Sparus aurata).

    PubMed

    Benedito-Palos, Laura; Calduch-Giner, Josep A; Ballester-Lozano, Gabriel F; Pérez-Sánchez, Jaume

    2013-04-14

    The effect of ration size on muscle fatty acid (FA) composition and mRNA expression levels of key regulatory enzymes of lipid and lipoprotein metabolism have been addressed in juveniles of gilthead sea bream fed a practical diet over the course of an 11-week trial. The experimental setup included three feeding levels: (i) full ration until visual satiety, (ii) 70 % of satiation and (iii) 70 % of satiation with the last 2 weeks at the maintenance ration. Feed restriction reduced lipid content of whole body by 30 % and that of fillet by 50 %. In this scenario, the FA composition of fillet TAG was not altered by ration size, whereas that of phospholipids was largely modified with a higher retention of arachidonic acid and DHA. The mRNA transcript levels of lysophosphatidylcholine acyltransferases, phosphatidylethanolamine N-methyltransferase and FA desaturase 2 were not regulated by ration size in the present experimental model. In contrast, mRNA levels of stearoyl-CoA desaturases were markedly down-regulated by feed restriction. An opposite trend was found for a muscle-specific lipoprotein lipase, which is exclusive of fish lineage. Several upstream regulatory transcriptions were also assessed, although nutritionally mediated changes in mRNA transcripts were almost reduced to PPARα and β, which might act in a counter-regulatory way on lipolysis and lipogenic pathways. This gene expression pattern contributes to the construction of a panel of biomarkers to direct marine fish production towards muscle lean phenotypes with increased retentions of long-chain PUFA. PMID:22856503

  3. Genome Pool Strategy for Structural Coverage of Protein Families

    SciTech Connect

    Jaroszewski, L.; Slabinski, L.; Wooley, J.; Deacon, A.M.; Lesley, S.A.; Wilson, I.A.; Godzik, A.

    2009-05-18

    Even closely homologous proteins often have different crystallization properties and propensities. This observation can be used to introduce an additional dimension into crystallization trials by simultaneous targeting multiple homologs in what we call a 'genome pool' strategy. We show that this strategy works because protein physicochemical properties correlated with crystallization success have a surprisingly broad distribution within most protein families. There are also easy and difficult families where this distribution is tilted in one direction. This leads to uneven structural coverage of protein families, with more easy ones solved. Increasing the size of the genome pool can improve chances of solving the difficult ones. In contrast, our analysis does not indicate that any specific genomes are easy or difficult. Finally, we show that the group of proteins with known 3D structures is systematically different from the general pool of known proteins and we assess the structural consequences of these differences.

  4. Gut microbiota, cirrhosis and alcohol regulate bile acid metabolism in the gut

    PubMed Central

    Ridlon, Jason M.; Kang, Dae-Joong; Hylemon, Phillip B.; Bajaj, Jasmohan S

    2015-01-01

    The understanding of the complex role of the bile acid-gut microbiome axis in health and disease processes is evolving rapidly. Our focus revolves around the interaction of the gut microbiota with liver diseases, especially cirrhosis. The bile acid pool size has recently been shown to be a function of microbial metabolism of bile acid and regulation of the microbiota by bile acids is important in the development and progression of several liver diseases. Humans produce a large, conjugated hydrophilic bile acid pool, maintained through positive-feedback antagonism of FXR in intestine and liver. Microbes use bile acids, and via FXR signaling this results in a smaller, unconjugated hydrophobic bile acid pool. This equilibrium is critical to maintain health. The challenge is to examine the manifold functions of gut bile acids as modulators of antibiotic, probiotic and disease progression in cirrhosis, metabolic syndrome and alcohol use. Recent studies have shown potential mechanisms explaining how perturbations in the microbiome affect bile acid pool size and composition. With advancing liver disease and cirrhosis, there is dysbiosis in the fecal, ileal and colonic mucosa, in addition to a decrease in bile acid concentration in the intestine due to the liver problems. This results in a dramatic shift toward the Firmicutes, particularly Clostridium cluster XIVa and increasing production of deoxycholic acid (DCA). Alcohol intake speeds up these processes in the subjects with and without cirrhosis without significant FXR feedback. Taken together, these pathways can impact intestinal and systemic inflammation while worsening dysbiosis. The interaction between bile acids, alcohol, cirrhosis and dysbiosis is an important relationship that influences intestinal and systemic inflammation, which in turn determines progression of the overall disease process. These interactions and the impact of commonly used therapies for liver disease can provide insight into the pathogenesis

  5. [Infections transmitted in swimming pools].

    PubMed

    von Suzani, C; Hazeghi, P

    1976-01-01

    Public swimmingpools can be the source of infections due to micro-organism such as mycobacterium balnei, adeno and enteroviruses, the virus of plantar warts and molluscum contagiosum, the TRIC-Agent of swimmingpool-conjonctivitis and pathogenic fungi. The transmission of trichomonas vaginalis is considered unlikely-Water of pools, supposed to present satisfactory qualities by standard controls, was found to contain pathogenic staphylococci and pseudomonas aeruginosa. Effective preventive measures include the continuous recording of the redox-potential of the water, limiting the number of visitors to pool design specifications, better desinfection of sanitary installations, regular maintenance of technical equipment including frequent backwashing of filters and exclusion of visitors with communicable disease.

  6. Synthesis of HAP nano rods and processing of nano-size ceramic reinforced poly(L)lactic acid composites

    NASA Astrophysics Data System (ADS)

    Flanigan, Kyle Yusef

    2000-09-01

    Bone is unique among the various connective tissues in that it is a composite of organic and inorganic components. Calcium phosphates occur principally in the form of hydroxyapatite crystals {Ca10(PO4) 6(OH)2}. Secreted apatite crystals are integral to the structural rigidity of the bone. When a bone breaks, there is often a need to implant an orthotic device to support the broken bone during remodeling. Current technologies use either metal pins and screws that need to be removed (by surgery) once the healing is complete or polymeric materials that either get resorbed or are porous enough to allow bone ingrowth. Poly(L)Lactic acid and copolymers of polyglycolic acid (PGA) are thermoplastics which show promise as the matrix material in biosorbable/load bearing implants. In service this material is hydrolyzed generating water and L-lactate. Orthoses composed of neat PLLA resins require greater than three years for complete resorbtion, however; 95% of strength is lost in 2 to 3 weeks in-vitro. This has limited the deployment of load bearing PLLA to screws, pins or short bracing spans. There exists a need for the development of an implantable and biosorbable orthotic device which will retain its structural integrity long enough for remodeling and healing process to generate new bone material, about 10 weeks. The scope of this dissertation is the development of HAP nano-whisker reinforcement and a HAP/PLLA thermoplastic composite. As proof of the feasibility of generating nano-reinforcement PLLA-composites, the surface of a galleried clay, montmorillonite, was modified and clay/PLLA composites processed and then characterized. Hydroxyapatite nano-whiskers were synthesized and functionalized using organosilanes and Menhaden fish-oil (common organic dispersant). The functionalized nano-fibers were used to process HAP/PLLA composites. Characterization techniques included thermal analysis, magnetic spectroscopy, XRD and ICP analysis and electron microscopy. The

  7. Micro-sized erosions in a nanofilled composite after repeated acidic beverage exposures: consequences of clusters dislodgments

    PubMed Central

    SVIZERO, Nádia da Rocha; de GÓES, Adriana Regina Cruz Grando; BUENO, Tamires de Luccas; DI HIPÓLITO, Vinicius; WANG, Linda; D'ALPINO, Paulo Henrique Perlatti

    2014-01-01

    Objective To evaluate the hardness (KHN), color stability (DE), and superficial micromorphology of two categories of composites after immersion in either distilled water or grape juice for up to 45 days. Material and Methods Cylindrical specimens (6 mm diameter x 2 mm thick) were obtained according to the factors: composite [Opallis (FGM) and Filtek Z350XT (3M ESPE)]; immersion solution (distilled water and grape juice); and evaluation time: 24 h and 7, 14, 21, 28, and 45 days. After photoactivation, the specimens were stored at 37ºC for 24 h. KHN (50 g/15 s) and ΔE were then repeatedly assessed according to the immersion solutions. Data were analyzed (three-way ANOVA/Tukey's test). Scanning electron microscopy (SEM) topographic analysis was also performed. Results In general, KHN of both composites reduced after 24 h, irrespective of the immersion solution and time. A significantly lower KHN was noted for Opallis compared with Filtek Z350XT in all parameters. An increase in ΔE over time was noted for both composites, irrespective of the immersion solution. Significantly higher ΔE was noted for Filtek Z350XT immersed in grape juice compared with Opallis, regardless of the evaluation time. The grape juice caused significantly higher DE compared with water in all periods. SEM analysis showed eroded areas for Filtek Z350XT but not for Opallis. Conclusions The compositions and immersion solutions influence the composite hardness and the color stability. In spite of the higher hardness, the nanofilled composite is more susceptible to color change than the microhybrid when immersed in an acidic dyed solution. PMID:25004054

  8. Pool power control in remelting systems

    DOEpatents

    Williamson, Rodney L.; Melgaard, David K.; Beaman, Joseph J.

    2011-12-13

    An apparatus for and method of controlling a remelting furnace comprising adjusting current supplied to an electrode based upon a predetermined pool power reference value and adjusting the electrode drive speed based upon the predetermined pool power reference value.

  9. Pool Safety: A Few Simple Rules.

    ERIC Educational Resources Information Center

    PTA Today, 1993

    1993-01-01

    Presents suggestions by the National Swimming Pool Safety Committee on how to keep children safe while swimming. Ideas include maintaining strict adult supervision, pool and spa barriers, and knowledge of cardiopulmonary resuscitation. (SM)

  10. Cold Pools in the Columbia Basin

    SciTech Connect

    Whiteman, Charles D.; Zhong, Shiyuan; Shaw, William J.; Hubbe, John M.; Bian, Xindi; Mittelstadt, J.

    2001-01-01

    Persistent midwinter cold air pools produce multi-day periods of cold, dreary weather in valleys and basins. Persistent stable stratification leads to the buildup of pollutants and moisture in the pool. Because the pool sometimes has temperatures below freezing while the air above is warmer, freezing precipitation often occurs with consequent effects on transportation and safety. Forecasting the buildup and breakdown of these cold pools is difficult because the physical mechanisms leading to their formation, maintenance, and destruction have received little study. This paper provides a succinct meteorological definition of a cold pool, develops a climatology of Columbia Basin cold pools, and analyzes remote and in situ temperature and wind sounding data for two winter cold pool episodes that were accompanied by fog and stratus, illustrating many of the physical mechanisms affecting cold pool evolution.

  11. CDC Study Finds Fecal Contamination in Pools

    MedlinePlus

    ... Communication (404) 639-3286 CDC study finds fecal contamination in pools A study of public pools done ... The E. coli is a marker for fecal contamination. Finding a high percentage of E. coli-positive ...

  12. Apparatus for heating a swimming pool

    SciTech Connect

    Kremen, R.D.

    1983-09-06

    This disclosure relates to a solar heater apparatus for a swimming pool which incorporates a submersible suspendible black body sheet to serve as a device to absorb solar radiation and transfer the collected energy to the pool water so that the pool water can be efficiently heated.

  13. 24 CFR 320.9 - Pool administration.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Pool administration. 320.9 Section...-BACKED SECURITIES Pass-Through Type Securities § 320.9 Pool administration. The Association will only... prescribed by the Association. Pool administration requirements are set forth in such agreements or...

  14. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  15. 10 CFR 429.24 - Pool heaters.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Pool heaters. 429.24 Section 429.24 Energy DEPARTMENT OF... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.24 Pool heaters. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to pool heaters; and (2) For...

  16. 10 CFR 429.24 - Pool heaters.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Pool heaters. 429.24 Section 429.24 Energy DEPARTMENT OF... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.24 Pool heaters. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to pool heaters; and (2) For...

  17. 10 CFR 36.33 - Irradiator pools.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Irradiator pools. 36.33 Section 36.33 Energy NUCLEAR... Requirements for Irradiators § 36.33 Irradiator pools. (a) For licenses initially issued after July 1, 1993, irradiator pools must either: (1) Have a water-tight stainless steel liner or a liner...

  18. 10 CFR 36.33 - Irradiator pools.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Irradiator pools. 36.33 Section 36.33 Energy NUCLEAR... Requirements for Irradiators § 36.33 Irradiator pools. (a) For licenses initially issued after July 1, 1993, irradiator pools must either: (1) Have a water-tight stainless steel liner or a liner...

  19. 10 CFR 36.33 - Irradiator pools.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Irradiator pools. 36.33 Section 36.33 Energy NUCLEAR... Requirements for Irradiators § 36.33 Irradiator pools. (a) For licenses initially issued after July 1, 1993, irradiator pools must either: (1) Have a water-tight stainless steel liner or a liner...

  20. 10 CFR 429.24 - Pool heaters.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Pool heaters. 429.24 Section 429.24 Energy DEPARTMENT OF... COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.24 Pool heaters. (a) Sampling plan for selection of units for testing. (1) The requirements of § 429.11 are applicable to pool heaters; and (2) For...

  1. 24 CFR 320.9 - Pool administration.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Pool administration. 320.9 Section...-BACKED SECURITIES Pass-Through Type Securities § 320.9 Pool administration. The Association will only... prescribed by the Association. Pool administration requirements are set forth in such agreements or...

  2. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  3. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  4. 24 CFR 320.9 - Pool administration.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Pool administration. 320.9 Section...-BACKED SECURITIES Pass-Through Type Securities § 320.9 Pool administration. The Association will only... prescribed by the Association. Pool administration requirements are set forth in such agreements or...

  5. 24 CFR 320.9 - Pool administration.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Pool administration. 320.9 Section...-BACKED SECURITIES Pass-Through Type Securities § 320.9 Pool administration. The Association will only... prescribed by the Association. Pool administration requirements are set forth in such agreements or...

  6. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  7. 7 CFR 1005.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1005.7 Section 1005.7 Agriculture... Handling Definitions § 1005.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  8. 7 CFR 1006.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1006.7 Section 1006.7 Agriculture... Handling Definitions § 1006.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  9. 7 CFR 1001.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1001.7 Section 1001.7 Agriculture... Handling Definitions § 1001.7 Pool plant. Pool plant means a plant, unit of plants, or system of plants as specified in paragraphs (a) through (f) of this section, but excluding a plant described in paragraph (h)...

  10. 7 CFR 1005.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1005.7 Section 1005.7 Agriculture... Handling Definitions § 1005.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  11. 7 CFR 1124.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1124.7 Section 1124.7 Agriculture... Regulating Handling Definitions § 1124.7 Pool plant. Pool plant means a plant, unit of plants, or a system of plants as specified in paragraphs (a) through (f) of this section, but excluding a plant specified...

  12. 7 CFR 1030.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1030.7 Section 1030.7 Agriculture... Handling Definitions § 1030.7 Pool plant. Pool plant means a plant, unit of plants, or system of plants as specified in paragraphs (a) through (f) of this section, but excluding a plant specified in paragraph (h)...

  13. 7 CFR 1001.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1001.7 Section 1001.7 Agriculture... Handling Definitions § 1001.7 Pool plant. Pool plant means a plant, unit of plants, or system of plants as specified in paragraphs (a) through (f) of this section, but excluding a plant described in paragraph (h)...

  14. 7 CFR 1033.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1033.7 Section 1033.7 Agriculture... Handling Definitions § 1033.7 Pool plant. Pool plant means a plant, unit of plants, or system of plants as specified in paragraphs (a) through (f) of this section, or a plant specified in paragraph (j) of...

  15. 7 CFR 1033.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1033.7 Section 1033.7 Agriculture... Handling Definitions § 1033.7 Pool plant. Pool plant means a plant, unit of plants, or system of plants as specified in paragraphs (a) through (f) of this section, or a plant specified in paragraph (j) of...

  16. 7 CFR 1131.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1131.7 Section 1131.7 Agriculture... Handling Definitions § 1131.7 Pool plant. Pool Plant means a plant or unit of plants specified in paragraphs (a) through (e) of this section, but excluding a plant specified in paragraph (g) of this...

  17. 7 CFR 1007.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1007.7 Section 1007.7 Agriculture... Handling Definitions § 1007.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  18. 7 CFR 1126.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1126.7 Section 1126.7 Agriculture... Handling Definitions § 1126.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  19. 7 CFR 1131.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1131.7 Section 1131.7 Agriculture... Handling Definitions § 1131.7 Pool plant. Pool Plant means a plant or unit of plants specified in paragraphs (a) through (e) of this section, but excluding a plant specified in paragraph (g) of this...

  20. 7 CFR 1032.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1032.7 Section 1032.7 Agriculture... Handling Definitions § 1032.7 Pool plant. Pool plant means a plant, unit of plants, or system of plants as specified in paragraphs (a) through (f) of this section, or a plant specified in paragraph (i) of...

  1. 7 CFR 1032.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1032.7 Section 1032.7 Agriculture... Handling Definitions § 1032.7 Pool plant. Pool plant means a plant, unit of plants, or system of plants as specified in paragraphs (a) through (f) of this section, or a plant specified in paragraph (i) of...

  2. 7 CFR 1007.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1007.7 Section 1007.7 Agriculture... Handling Definitions § 1007.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  3. 7 CFR 1006.7 - Pool plant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Pool plant. 1006.7 Section 1006.7 Agriculture... Handling Definitions § 1006.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  4. 7 CFR 1126.7 - Pool plant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Pool plant. 1126.7 Section 1126.7 Agriculture... Handling Definitions § 1126.7 Pool plant. Pool plant means a plant specified in paragraphs (a) through (d) of this section, a unit of plants as specified in paragraph (e) of this section, or a plant...

  5. 28 CFR 540.64 - Press pools.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Press pools. 540.64 Section 540.64... PERSONS IN THE COMMUNITY Contact With News Media § 540.64 Press pools. (a) The Warden may establish a press pool whenever he or she determines that the frequency of requests for interviews and...

  6. 24 CFR 320.9 - Pool administration.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Pool administration. 320.9 Section...-BACKED SECURITIES Pass-Through Type Securities § 320.9 Pool administration. The Association will only... prescribed by the Association. Pool administration requirements are set forth in such agreements or...

  7. 1968 Listing of Swimming Pool Equipment.

    ERIC Educational Resources Information Center

    National Sanitation Foundation, Ann Arbor, MI. Testing Lab.

    An up-to-date listing of swimming pool equipment including--(1) companies authorized to display the National Sanitation Foundation seal of approval, (2) equipment listed as meeting NSF swimming pool equipment standards relating to diatomite type filters, (3) equipment listed as meeting NSF swimming pool equipment standard relating to sand type…

  8. Bioanalytical and chemical evaluation of disinfection by-products in swimming pool water.

    PubMed

    Yeh, Ruby Y L; Farré, Maria José; Stalter, Daniel; Tang, Janet Y M; Molendijk, Jeffrey; Escher, Beate I

    2014-08-01

    Pool water disinfection is vital to prevent microbial pathogens. However, potentially hazardous disinfection by-products (DBP) are formed from the reaction between disinfectants and organic/inorganic precursors. The aim of this study was to evaluate the presence of DBPs in various swimming pool types in Brisbane, Australia, including outdoor, indoor and baby pools, and the dynamics after a complete water renewal. Chemical analysis of 36 regulated and commonly found DBPs and total adsorbable organic halogens as well as in vitro bioassays targeting cytotoxicity, oxidative stress and genotoxicity were used to evaluate swimming pool water quality. Dichloroacetic acid and trichloroacetic acid dominated in the pool water samples with higher levels (up to 2600 μg/L) than the health guideline values set by the Australian Drinking Water Guidelines (100 μg/L). Chlorinated DBPs occurred at higher concentrations compared to tap water, while brominated DBPs decreased gradually with increasing pool water age. Biological effects were expressed as chloroacetic acid equivalent concentrations and compared to predicted effects from chemical analysis and biological characterisation of haloacetic acids. The quantified haloacetic acids explained 35-118% of the absorbable organic halogens but less than 4% of the observed non-specific toxicity (cytotoxicity), and less than 1% of the observed oxidative stress response and genotoxicity. While the DBP concentrations in Australian pools found in this study are not likely to cause any adverse health effect, they are higher than in other countries and could be reduced by better hygiene of pool users, such as thorough showering prior to entering the pool and avoiding urination during swimming.

  9. [Continuing medical education in Aesthetic Medicine: hands--on course on the usage of hyaluronic acids of different particle size on anatomic preparations].

    PubMed

    Reytan, Natalie; Plaschke, Martina; Hund, Martina; Bogusch, Gottfried; Rzany, Berthold

    2007-03-01

    The Division of Evidence Based Medicine (dEBM), Clinic for Dermatology, Venerology and Allergology, Charité--Universitätsmedizin Berlin, offers on a regular basis workshops focusing on different areas of aesthetic medicine. Once a year a joint course is provided in cooperation with the Institute of Anatomy, offering the participants the possibility to improve their injection techniques as well as their knowledge on the facial anatomy. This course is focused on treatment with hyaluronic acids of different particle size. Besides the classical indications, it considers new indications such as correcting the shape of the nose or lacrimal groove. Thirteen physicians participated in the course, which was evaluated as very helpful as it improved not only the injection technique but also the knowledge of anatomy.

  10. Fine-sized Tb3Al5O12:Ce phosphor powders prepared by spray pyrolysis from spray solution with ethylenediaminetetraacetic acid

    NASA Astrophysics Data System (ADS)

    Kim, Hyung Tae; Kim, Jung Hyun; Hong, Young Jun; Lee, Jung-Kul; Kang, Yun Chan

    2012-06-01

    Fine Tb2.91Al5O12:Ce0.09 (TAG:Ce) phosphor powders are prepared by spray pyrolysis from a spray solution with ethylenediaminetetraacetic acid (EDTA). EDTA is used as an organic additive to form hollow precursor powders as well as a chelating agent. The powders prepared from the spray solution with EDTA have mean sizes of 350, 400 and 604 nm at post-treatment temperatures of 1400°C, 1450°C and 1500°C, respectively. The phosphor powders prepared from the spray solution with EDTA have similar photoluminescence intensities at post-treatment temperatures of 1450°C and 1500°C. The photoluminescence intensity of the phosphor powders prepared from the spray solution with EDTA is 116% of that of the phosphor powders prepared from the spray solution without EDTA at a post-treatment temperature of 1450°C.

  11. The size and shape of three water-soluble, non-ionic polysaccharides produced by lactic acid bacteria: A comparative study.

    PubMed

    Dalheim, Marianne Øksnes; Arnfinnsdottir, Nina Bjørk; Widmalm, Göran; Christensen, Bjørn E

    2016-05-20

    Three water-soluble, non-ionic extracellular polysaccharides (EPS) obtained from lactic acid bacteria (S. thermophilus THS, L. helveticus K16 and S. thermophilus ST1) were subjected to a comparative study by means of multidetector size-exclusion chromatography, providing distributions and averages of molar masses, radii of gyration and intrinsic viscosities. All polysaccharides displayed random coil character. Further analysis of the data reveals differences in chain stiffness and extension that could be well correlated to structural features. The calculated persistence lengths ranged from 5 to 10nm and fall within the range typical for many single-stranded bacterial or plant polysaccharides. The ST1 polysaccharide had the highest molar mass but the lowest persistence length, which is attributed to the presence of the flexible (1→6)-linkage in the main chain. PMID:26917378

  12. Patent Pools: Intellectual Property Rights and Competition

    PubMed Central

    Rodriguez, Victor

    2010-01-01

    Patent pools do not correct all problems associated with patent thickets. In this respect, patent pools might not stop the outsider problem from striking pools. Moreover, patent pools can be expensive to negotiate, can exclude patent holders with smaller numbers of patents or enable a group of major players to form a cartel that excludes new competitors. For all the above reasons, patent pools are subject to regulatory clearance because they could result in a monopoly. The aim of this article is to present the relationship between patents and competition in a broad context. PMID:20200607

  13. Method of measuring a liquid pool volume

    DOEpatents

    Garcia, G.V.; Carlson, N.M.; Donaldson, A.D.

    1991-03-19

    A method of measuring a molten metal liquid pool volume and in particular molten titanium liquid pools is disclosed, including the steps of (a) generating an ultrasonic wave at the surface of the molten metal liquid pool, (b) shining a light on the surface of a molten metal liquid pool, (c) detecting a change in the frequency of light, (d) detecting an ultrasonic wave echo at the surface of the molten metal liquid pool, and (e) computing the volume of the molten metal liquid. 3 figures.

  14. Influence of position and size of substituents on the mechanism of partitioning: a thermodynamic study on acetaminophens, hydroxybenzoic acids, and parabens.

    PubMed

    Perlovich, German L; Volkova, Tatyana V; Manin, Alex N; Bauer-Brandl, Annette

    2008-01-01

    The objective of the present investigation was to study the influence of size, nature, and topology of substituents on the thermodynamic characteristics of sublimation, fusion, solubility, solvation, and partitioning processes of some drug and druglike molecules. Thermodynamic functions of sublimation process 2-acetaminophen and 3-acetaminophen were obtained on the basis of temperature dependencies of vapor pressure by the transpiration method. Thermodynamic characteristics of solubility processes in water, n-octanol, and n-hexane were calculated from the temperature dependencies of solubility using the solubility saturation method. For evaluation of fusion parameters, differential scanning calorimetry was used. A new approach to distinguishing specific and nonspecific energetic terms in the crystal lattice was developed. Specific and nonspecific solvation terms were distinguished using the transfer from the "inert" n-hexane to the other solvents. For the acetaminophen compounds and for some related drug molecules, the correlation between melting points and a parameter describing the ratio between specific and nonspecific interaction in the crystal lattices was obtained. A diagram enabling analysis of the mechanism of the partitioning process was applied. It was found that for isomers of benzoic acids and for acetaminophens, the position of substituents affects the mechanism of the partitioning process but not the extent of partitioning (DeltaG(tr)(0) values). In contrast to this, an increased size of substituents (parabens) leads to essential changes in DeltaG(tr)(0) values, but the mechanism of the partitioning process stays the same. PMID:18446483

  15. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater--Using humic acid and iron nano-sized colloids as test particles.

    PubMed

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret; Baun, Anders; Eriksson, Eva

    2015-11-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution of low-molecular weight PAHs (LMW PAHs), middle-molecular weight PAHs (MMW PAHs) and high-molecular weight PAHs (HMW PAHs) among the fractions was also evaluated. The results from the synthetic suspensions showed that the highest concentrations of the PAHs were found in the Filtrated fractions and, surprisingly, high loads were found in the Dissolved fractions. The PAHs identified in stormwater in the Particulate fractions and Dissolved fractions follow their hydrophobic properties. In most samples >50% of the HMW PAHs were found in the Particulate fractions, while the LMW and MMW PAHs were found to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMW PAHs was highest in the Particulate fractions (particles>0.7 μm). The highest concentration of PAHs in the Colloidal fraction was found in the sample with occurrence of small nano-sized particles (<10nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater.

  16. Drowning in disinfection byproducts? Assessing swimming pool water.

    PubMed

    Zwiener, Christian; Richardson, Susan D; DeMarini, David M; De Marini, David M; Grummt, Tamara; Glauner, Thomas; Frimmel, Fritz H

    2007-01-15

    Disinfection is mandatory for swimming pools: public pools are usually disinfected by gaseous chlorine or sodium hypochlorite and cartridge filters; home pools typically use stabilized chlorine. These methods produce a variety of disinfection byproducts (DBPs), such as trihalomethanes (THMs), which are regulated carcinogenic DBPs in drinking water that have been detected in the blood and breath of swimmers and of nonswimmers at indoor pools. Also produced are halogenated acetic acids (HAAs) and haloketones, which irritate the eyes, skin, and mucous membranes; trichloramine, which is linked with swimming-pool-associated asthma; and halogenated derivatives of UV sun screens, some of which show endocrine effects. Precursors of DBPs include human body substances, chemicals used in cosmetics and sun screens, and natural organic matter. Analytical research has focused also on the identification of an additional portion of unknown DBPs using gas chromatography (GC)/mass spectrometry (MS) and liquid chromatography (LC)/MS/MS with derivatization. Children swimmers have an increased risk of developing asthma and infections of the respiratory tract and ear. A 1.6-2.0-fold increased risk for bladder cancer has been associated with swimming or showering/bathing with chlorinated water. Bladder cancer risk from THM exposure (all routes combined) was greatest among those with the GSTT1-1 gene. This suggests a mechanism involving distribution of THMs to the bladder by dermal/inhalation exposure and activation there by GSTT1-1 to mutagens. DBPs may be reduced by engineering and behavioral means, such as applying new oxidation and filtration methods, reducing bromide and iodide in the source water, increasing air circulation in indoor pools, and assuring the cleanliness of swimmers. The positive health effects gained by swimming can be increased by reducing the potential adverse health risks. PMID:17310693

  17. Double-observer approach to estimating egg mass abundance of vernal pool breeding amphibians

    USGS Publications Warehouse

    Grant, E.H.C.; Jung, R.E.; Nichols, J.D.; Hines, J.E.

    2005-01-01

    Interest in seasonally flooded pools, and the status of associated amphibian populations, has initiated programs in the northeastern United States to document and monitor these habitats. Counting egg masses is an effective way to determine the population size of pool-breeding amphibians, such as wood frogs (Rana sylvatica) and spotted salamanders (Ambystoma maculatum). However, bias is associated with counts if egg masses are missed. Counts unadjusted for the proportion missed (i.e., without adjustment for detection probability) could lead to false assessments of population trends. We used a dependent double-observer method in 2002-2003 to estimate numbers of wood frog and spotted salamander egg masses at seasonal forest pools in 13 National Wildlife Refuges, 1 National Park, 1 National Seashore, and 1 State Park in the northeastern United States. We calculated detection probabilities for egg masses and examined whether detection probabilities varied by species, observers, pools, and in relation to pool characteristics (pool area, pool maximum depth, within-pool vegetation). For the 2 years, model selection indicated that no consistent set of variables explained the variation in data sets from individual Refuges and Parks. Because our results indicated that egg mass detection probabilities vary spatially and temporally, we conclude that it is essential to use estimation procedures, such as double-observer methods with egg mass surveys, to determine population sizes and trends of these species.

  18. A unified model of coupled arc plasma and weld pool for double electrodes TIG welding

    NASA Astrophysics Data System (ADS)

    Wang, Xinxin; Fan, Ding; Huang, Jiankang; Huang, Yong

    2014-07-01

    A three-dimensional model containing tungsten electrodes, arc plasma and a weld pool is presented for double electrodes tungsten inert gas welding. The model is validated by available experimental data. The distributions of temperature, velocity and pressure of the coupled arc plasma are investigated. The current density, heat flux and shear stress over the weld pool are highlighted. The weld pool dynamic is described by taking into account buoyance, Lorentz force, surface tension and plasma drag force. The turbulent effect in the weld pool is also considered. It is found that the temperature and velocity distributions of the coupled arc are not rotationally symmetrical. A similar property is also shown by the arc pressure, current density and heat flux at the anode surface. The surface tension gradient is much larger than the plasma drag force and dominates the convective pattern in the weld pool, thus determining the weld penetration. The anodic heat flux and plasma drag force, as well as the surface tension gradient over the weld pool, determine the weld shape and size. In addition, provided the welding current through one electrode increases and that through the other decreases, keeping the total current unchanged, the coupled arc behaviour and weld pool dynamic change significantly, while the weld shape and size show little change. The results demonstrate the necessity of a unified model in the study of the arc plasma and weld pool.

  19. An Innovative Hybrid Loop-Pool Design for Sodium Cooled Fast Reactor

    SciTech Connect

    Haihua Zhao; Hongbin Zhang

    2007-11-01

    The existing sodium cooled fast reactors (SFR) have two types of designs – loop type and pool type. In the loop type design, such as JOYO (Japan) [1] and MONJU (Japan), the primary coolant is circulated through intermediate heat exchangers (IHX) external to the reactor tank. The major advantages of loop design include compactness and easy maintenance. The disadvantage is higher possibility of sodium leakage. In the pool type design such as EBR-II (USA), BN-600M(Russia), Superphénix (France) and European Fast Reactor [2], the reactor core, primary pumps, IHXs and direct reactor auxiliary cooling system (DRACS) heat exchangers (DHX) all are immersed in a pool of sodium coolant within the reactor vessel, making a loss of primary coolant extremely unlikely. However, the pool type design makes primary system large. In the latest ANL’s Advanced Burner Test Reactor (ABTR) design [3], the primary system is configured in a pool-type arrangement. The hot sodium at core outlet temperature in hot pool is separated from the cold sodium at core inlet temperature in cold pool by a single integrated structure called Redan. Redan provides the exchange of the hot sodium from hot pool to cold pool through IHXs. The IHXs were chosen as the traditional tube-shell design. This type of IHXs is large in size and hence large reactor vessel is needed.

  20. Occurrence and human exposure of parabens and their chlorinated derivatives in swimming pools.

    PubMed

    Li, Wenhui; Shi, Yali; Gao, Lihong; Liu, Jiemin; Cai, Yaqi

    2015-11-01

    As an emerging group of endocrine-disrupting chemicals, parabens have attracted growing attention due to their potential effects on human health. In the present study, the occurrence and distribution of eight parabens, four chlorinated parabens, and their common hydrolysis product, p-hydroxybenzoic acid (PHBA), were investigated in 39 swimming pools in Beijing, China. Methyl paraben and propyl paraben were the predominant compounds in swimming pools, accounting for 91.2 % of the total parabens. It is noteworthy that octyl paraben, a paraben with longer chain, was firstly detected in this study. There were several factors affecting the levels of parabens among the 39 swimming pools. The concentrations of parabens and chlorinated derivatives detected in indoor pools (144 ng L(-1)) were roughly 20-fold higher than those in outdoor pools (6.78 ng L(-1)). Hotel pools appear to present higher level of target compounds (361 ng L(-1)) than that in health club (228 ng L(-1)), municipal (130 ng L(-1)), school (75.6 ng L(-1)), and community pools (63.0 ng L(-1)). Moreover, the level of these compounds in pools during weekends (174 ng L(-1)) was much higher than that during weekdays (52.3 ng L(-1)). The dynamics of target compounds were also investigated to provide a general trend of the level of parabens in a school indoor swimming pool during a 14-week period. Human exposure assessment was conducted to estimate the potential risk of exposure to parabens and their chlorinated derivatives in swimming pools. Considering the total exposure dose of multiple parabens, human exposure to parabens from the water of swimming pools is negligible. However, the threat of these parabens to children in swimming pool should be concerned.

  1. The output from human inspiratory motoneurone pools

    PubMed Central

    Butler, Jane E; Gandevia, Simon C

    2008-01-01

    Survival requires adequate pulmonary ventilation which, in turn, depends on adequate contraction of muscles acting on the chest wall in the presence of a patent upper airway. Bulbospinal outputs projecting directly and indirectly to ‘obligatory’ respiratory motoneurone pools generate the required muscle contractions. Recent studies of the phasic inspiratory output of populations of single motor units to five muscles acting on the chest wall (including the diaphragm) reveal that the time of onset, the progressive recruitment, and the amount of motoneuronal drive (expressed as firing frequency) differ among the muscles. Tonic firing with an inspiratory modulation of firing rate is common in low intercostal spaces of the parasternal and external intercostal muscles but rare in the diaphragm. A new time and frequency plot has been developed to depict the behaviour of the motoneurone populations. The magnitude of inspiratory firing of motor unit populations is linearly correlated to the mechanical advantage of the intercostal muscle region at which the motor unit activity is recorded. This represents a ‘neuromechanical’ principle by which the CNS controls motoneuronal output according to mechanical advantage, presumably in addition to the Henneman's size principle of motoneurone recruitment. Studies of the genioglossus, an obligatory upper airway muscle that helps maintain airway patency, reveal that it receives simultaneous inspiratory, expiratory and tonic drives even during quiet breathing. There is much to be learned about the neural drive to pools of human inspiratory and expiratory muscles, not only during respiratory tasks but also in automatic and volitional tasks, and in diseases that alter the required drive. PMID:17974589

  2. Leidenfrost drops on a heated liquid pool

    NASA Astrophysics Data System (ADS)

    Maquet, L.; Sobac, B.; Darbois-Texier, B.; Duchesne, A.; Brandenbourger, M.; Rednikov, A.; Colinet, P.; Dorbolo, S.

    2016-09-01

    We show that a volatile liquid drop placed at the surface of a nonvolatile liquid pool warmer than the boiling point of the drop can be held in a Leidenfrost state even for vanishingly small superheats. Such an observation points to the importance of the substrate roughness, negligible in the case considered here, in determining the threshold Leidenfrost temperature. A theoretical model based on the one proposed by Sobac et al. [Phys. Rev. E 90, 053011 (2014), 10.1103/PhysRevE.90.053011] is developed in order to rationalize the experimental data. The shapes of the drop and of the liquid substrate are analyzed. The model notably provides scalings for the vapor film thickness profile. For small drops, these scalings appear to be identical to the case of a Leidenfrost drop on a solid substrate. For large drops, in contrast, they are different, and no evidence of chimney formation has been observed either experimentally or theoretically in the range of drop sizes considered in this study. Concerning the evaporation dynamics, the radius is shown to decrease linearly with time whatever the drop size, which differs from the case of a Leidenfrost drop on a solid substrate. For high superheats, the characteristic lifetime of the drops versus the superheat follows a scaling law that is derived from the model, but, at low superheats, it deviates from this scaling by rather saturating.

  3. Just like the lottery? Player behaviour and anomalies in the market for football pools.

    PubMed

    Forrest, David; Pérez, Levi

    2015-06-01

    Football pools were an antecedent to lotto in providing a long-odds, high-prize gambling opportunity for a mass market in Europe. Even after lotto has become well established, pools games continue to occupy a significant niche in the gaming market in several jurisdictions, most notably Spain. This paper employs 23 years of sales data from the national pools game in Spain to investigate similarities between the behaviour of lotto players and pools players. It observes similar phenomena as have been noted in lotto sales studies, including strong sensitivity of sales to the size of jackpot on offer, significant habit effects, a halo effect whereby there is some short-term persistence in increased sales whenever a high jackpot is offered (even after jackpot size has returned to normal), and a tendency to jackpot fatigue (over time, the size of the jackpot has to be increased to more than before to stimulate the same increase in sales). Notwithstanding that the football pools are marketed as based on knowledge and understanding of sport whereas lotto is a pure numbers game, modelling sales of the pools therefore yields findings very similar to those reported in the literature on lotto. This suggests that both sets of players share common psychological and cognitive traits and economic motivation. Those responsible for promoting pools should therefore be able to draw on findings from the much more extensive literature on lotto when formulating strategy in terms of game design and marketing. PMID:24292983

  4. Just like the lottery? Player behaviour and anomalies in the market for football pools.

    PubMed

    Forrest, David; Pérez, Levi

    2015-06-01

    Football pools were an antecedent to lotto in providing a long-odds, high-prize gambling opportunity for a mass market in Europe. Even after lotto has become well established, pools games continue to occupy a significant niche in the gaming market in several jurisdictions, most notably Spain. This paper employs 23 years of sales data from the national pools game in Spain to investigate similarities between the behaviour of lotto players and pools players. It observes similar phenomena as have been noted in lotto sales studies, including strong sensitivity of sales to the size of jackpot on offer, significant habit effects, a halo effect whereby there is some short-term persistence in increased sales whenever a high jackpot is offered (even after jackpot size has returned to normal), and a tendency to jackpot fatigue (over time, the size of the jackpot has to be increased to more than before to stimulate the same increase in sales). Notwithstanding that the football pools are marketed as based on knowledge and understanding of sport whereas lotto is a pure numbers game, modelling sales of the pools therefore yields findings very similar to those reported in the literature on lotto. This suggests that both sets of players share common psychological and cognitive traits and economic motivation. Those responsible for promoting pools should therefore be able to draw on findings from the much more extensive literature on lotto when formulating strategy in terms of game design and marketing.

  5. 1. OBLIQUE VIEW OF THE POOL BUILDING 307 AND THE ...

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

    1. OBLIQUE VIEW OF THE POOL BUILDING 307 AND THE POOL 308, LOOKING WEST. - Mill Valley Air Force Station, Pool Building & Swimming Pool, East Ridgecrest Boulevard, Mount Tamalpais, Mill Valley, Marin County, CA

  6. Two distinct pools of membrane phosphatidylglycerol in Bacillus megaterium.

    PubMed Central

    Lombardi, F J; Fulco, A J

    1980-01-01

    The predominant membrane lipid in Bacillus megaterium ATCC 14581, phosphatidylglycerol (PG), is present in two distinct pools, as shown by [32P]phosphate incorporation and chase experiments. One pool (PGt) undergoes rapid turnover of the phosphate moiety, whereas the second pool (PGs) exhibits metabolic stability in this group. The phosphate moiety of the other major phospholipid, phosphatidylethanolamine, is stable to turnover. [32P]phosphate- and [2-3H]glycerol-equilibrated cultures yielded the following glycerolipid composition: 56 mol% PG (34 mol% PGt and 22 mol% PGs), 21 mol% phosphatidylethanolamine, 1 to 2 mol% phosphatidylserine, 20 mol% diglycerides, less than 0.5 mol% cardiolipin, and 0.2 to 0.4 mol% lysophosphatidylglycerol. Accumulation of PG was halted immediately after the addition of cerulenin, an inhibitor of de novo fatty acid synthesis, whereas phosphatidylethanolamine accumulation continued at the expense of the diglyceride and PG pools. Strikingly, initial rates of [32P]phosphate incorporation into PG were unaffected by cerulenin. In control cultures at 35 degrees C, incorporation of [32P]phosphate into PG exhibited a biphasic time course, whereas incorporation into phosphatidylethanolamine was concave upward and lagged behind that of PG during the initial rapid phase of PG incorporation. Finally, levels of lysophosphatidylglycerol expanded rapidly after cerulenin addition at 20 degrees C, but not at 35 degrees C. Moreover, incorporation of [32P]phosphate into lysophosphatidylglycerol lagged behind incorporation into PG in both the presence and absence of cerulenin at 20 and 35 degrees C. PMID:6767685

  7. Two distinct pools of membrane phosphatidylglycerol in Bacillus megaterium.

    PubMed

    Lombardi, F J; Fulco, A J

    1980-02-01

    The predominant membrane lipid in Bacillus megaterium ATCC 14581, phosphatidylglycerol (PG), is present in two distinct pools, as shown by [32P]phosphate incorporation and chase experiments. One pool (PGt) undergoes rapid turnover of the phosphate moiety, whereas the second pool (PGs) exhibits metabolic stability in this group. The phosphate moiety of the other major phospholipid, phosphatidylethanolamine, is stable to turnover. [32P]phosphate- and [2-3H]glycerol-equilibrated cultures yielded the following glycerolipid composition: 56 mol% PG (34 mol% PGt and 22 mol% PGs), 21 mol% phosphatidylethanolamine, 1 to 2 mol% phosphatidylserine, 20 mol% diglycerides, less than 0.5 mol% cardiolipin, and 0.2 to 0.4 mol% lysophosphatidylglycerol. Accumulation of PG was halted immediately after the addition of cerulenin, an inhibitor of de novo fatty acid synthesis, whereas phosphatidylethanolamine accumulation continued at the expense of the diglyceride and PG pools. Strikingly, initial rates of [32P]phosphate incorporation into PG were unaffected by cerulenin. In control cultures at 35 degrees C, incorporation of [32P]phosphate into PG exhibited a biphasic time course, whereas incorporation into phosphatidylethanolamine was concave upward and lagged behind that of PG during the initial rapid phase of PG incorporation. Finally, levels of lysophosphatidylglycerol expanded rapidly after cerulenin addition at 20 degrees C, but not at 35 degrees C. Moreover, incorporation of [32P]phosphate into lysophosphatidylglycerol lagged behind incorporation into PG in both the presence and absence of cerulenin at 20 and 35 degrees C. PMID:6767685

  8. Quantifying Protein Synthesis and Degradation in Arabidopsis by Dynamic 13CO2 Labeling and Analysis of Enrichment in Individual Amino Acids in Their Free Pools and in Protein1[OPEN

    PubMed Central

    Fernie, Alisdair R.; Stitt, Mark

    2015-01-01

    Protein synthesis and degradation represent substantial costs during plant growth. To obtain a quantitative measure of the rate of protein synthesis and degradation, we supplied 13CO2 to intact Arabidopsis (Arabidopsis thaliana) Columbia-0 plants and analyzed enrichment in free amino acids and in amino acid residues in protein during a 24-h pulse and 4-d chase. While many free amino acids labeled slowly and incompletely, alanine showed a rapid rise in enrichment in the pulse and a decrease in the chase. Enrichment in free alanine was used to correct enrichment in alanine residues in protein and calculate the rate of protein synthesis. The latter was compared with the relative growth rate to estimate the rate of protein degradation. The relative growth rate was estimated from sequential determination of fresh weight, sequential images of rosette area, and labeling of glucose in the cell wall. In an 8-h photoperiod, protein synthesis and cell wall synthesis were 3-fold faster in the day than at night, protein degradation was slow (3%–4% d−1), and flux to growth and degradation resulted in a protein half-life of 3.5 d. In the starchless phosphoglucomutase mutant at night, protein synthesis was further decreased and protein degradation increased, while cell wall synthesis was totally inhibited, quantitatively accounting for the inhibition of growth in this mutant. We also investigated the rates of protein synthesis and degradation during leaf development, during growth at high temperature, and compared synthesis rates of Rubisco large and small subunits of in the light and dark. PMID:25810096

  9. 13 CFR 120.1709 - Transfers of Pool Certificates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... transfer. The Pool Investor must supply the following information in the letter: (1) Pool number; (2) Pool... recovery. At the same time a Pool Investor submits a letter of transmittal for a Pool Certificate pursuant... will supply the transfer information to the Pool Investor....

  10. Radioisotope Power System Pool Concept

    NASA Technical Reports Server (NTRS)

    Rusick, Jeffrey J.; Bolotin, Gary S.

    2015-01-01

    Advanced Radioisotope Power Systems (RPS) for NASA deep space science missions have historically used static thermoelectric-based designs because they are highly reliable, and their radioisotope heat sources can be passively cooled throughout the mission life cycle. Recently, a significant effort to develop a dynamic RPS, the Advanced Stirling Radioisotope Generator (ASRG), was conducted by NASA and the Department of Energy, because Stirling based designs offer energy conversion efficiencies four times higher than heritage thermoelectric designs; and the efficiency would proportionately reduce the amount of radioisotope fuel needed for the same power output. However, the long term reliability of a Stirling based design is a concern compared to thermoelectric designs, because for certain Stirling system architectures the radioisotope heat sources must be actively cooled via the dynamic operation of Stirling converters throughout the mission life cycle. To address this reliability concern, a new dynamic Stirling cycle RPS architecture is proposed called the RPS Pool Concept.

  11. Biliary lipids, bile acids, and gallbladder function in the human female:effects of contraceptive steroids

    SciTech Connect

    Kern, F., Jr.; Everson, G.T.; DeMark, B.; McKinley, C.; Showalter, R.; Braverman, D.Z.; Szczepanik-Van Leeuwen, P.; Klein, P.D.

    1982-06-01

    Reported are biliary lipid composition and secretion, bile acid composition and kinetics, and gallbladder function in a group of healthy, nonobese women taking a contraceptive steroid preparation. A comparable group of healthy women served as controls. Biliary lipid secretion rate was measured by the marker perfusion technique. Bile acid distribution was determined by gas-lipid chromatography. The pool size, FTR, and synthesis rate of each bile acid were measured by using CA and CDCA labeled with the stable isotope of carbon, /sup 13/C. In some of the subjects gallbladder storage and emptying were measured during the kinetic study, by real-time ultrasonography. Contraceptive steroid use was associated with a significant increase in biliary cholesterol saturation and in the lithogenic index of bile. The rate of cholesterol secretion in the contraceptive steroid group was 50% greater than in the control (p << 0.001) and the rate of bile acid secretion was reduced (p < 0.02). The total bile acid pool size was significantly increased by contraceptive steroids. The major increase occurred in the CA pool (p < 0.04). The daily rate of enterohepatic cycles of the bile acid pool was decreased by contraceptive steroids from 6.6 to 4.3 (p < 0.01). The only effect of contraceptive steroids on gallbladder function was a slower emptying rate in response to intraduodenal amino acid infusion. No index of gallbladder function correlated significantly with any parameter of bile acid kinetics in this small group of subjects. The findings confirm the lithogenic effect of contraceptive steroids and indicate that its causes are an increase in cholesterol secretion and a decrease in bile acid secretion.

  12. Spatial Pyramid Pooling in Deep Convolutional Networks for Visual Recognition.

    PubMed

    He, Kaiming; Zhang, Xiangyu; Ren, Shaoqing; Sun, Jian

    2015-09-01

    Existing deep convolutional neural networks (CNNs) require a fixed-size (e.g., 224 × 224) input image. This requirement is "artificial" and may reduce the recognition accuracy for the images or sub-images of an arbitrary size/scale. In this work, we equip the networks with another pooling strategy, "spatial pyramid pooling", to eliminate the above requirement. The new network structure, called SPP-net, can generate a fixed-length representation regardless of image size/scale. Pyramid pooling is also robust to object deformations. With these advantages, SPP-net should in general improve all CNN-based image classification methods. On the ImageNet 2012 dataset, we demonstrate that SPP-net boosts the accuracy of a variety of CNN architectures despite their different designs. On the Pascal VOC 2007 and Caltech101 datasets, SPP-net achieves state-of-the-art classification results using a single full-image representation and no fine-tuning. The power of SPP-net is also significant in object detection. Using SPP-net, we compute the feature maps from the entire image only once, and then pool features in arbitrary regions (sub-images) to generate fixed-length representations for training the detectors. This method avoids repeatedly computing the convolutional features. In processing test images, our method is 24-102 × faster than the R-CNN method, while achieving better or comparable accuracy on Pascal VOC 2007. In ImageNet Large Scale Visual Recognition Challenge (ILSVRC) 2014, our methods rank #2 in object detection and #3 in image classification among all 38 teams. This manuscript also introduces the improvement made for this competition.

  13. Analysis of an open-air swimming pool solar heating system by using an experimentally validated TRNSYS model

    SciTech Connect

    Ruiz, Elisa; Martinez, Pedro J.

    2010-01-15

    In the case of private outdoor swimming pools, seldom larger than 100 m{sup 2}, conventional auxiliary heating systems are being installed less and less. Solar heating is an option to extend the swimming season. The temperature evolution of an open-air swimming pool highly depends on the wind speed directly on the water surface, which at the same time is influenced by the surroundings of the pool. In this paper, the TRNSYS model of a private open-air pool with a 50-m{sup 2} surface was validated by registering the water temperature evolution and the meteorological data at the pool site. Evaporation is the main component of energy loss in swimming pools. Six different sets of constants found in literature were considered to evaluate the evaporative heat transfer coefficient with the purpose of finding the most suitable one for the TRNSYS pool model. In order to do that, the evolution of the pool water temperature predicted by the TRNSYS pool model was compared with the experimentally registered one. The simulation with TRNSYS of the total system, including the swimming pool and the absorber circuit integrated into the existing filter circuit, provided information regarding the increase of the pool temperature for different collector areas during the swimming season. This knowledge, together with the economic costs, support the decision about the absorber field size. (author)

  14. Safety Evaluation of a Bioglass–Polylactic Acid Composite Scaffold Seeded with Progenitor Cells in a Rat Skull Critical-Size Bone Defect

    PubMed Central

    El-Kady, Abeer M.; Arbid, Mahmoud S.; Abd El-Hady, Bothaina M.; Marzi, Ingo; Seebach, Caroline

    2014-01-01

    Treating large bone defects represents a major challenge in traumatic and orthopedic surgery. Bone tissue engineering provides a promising therapeutic option to improve the local bone healing response. In the present study tissue biocompatibility, systemic toxicity and tumorigenicity of a newly developed composite material consisting of polylactic acid (PLA) and 20% or 40% bioglass (BG20 and BG40), respectively, were analyzed. These materials were seeded with mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) and tested in a rat calvarial critical size defect model for 3 months and compared to a scaffold consisting only of PLA. Serum was analyzed for organ damage markers such as GOT and creatinine. Leukocyte count, temperature and free radical indicators were measured to determine the degree of systemic inflammation. Possible tumor occurrence was assessed macroscopically and histologically in slides of liver, kidney and spleen. Furthermore, the concentrations of serum malondialdehyde (MDA) and sodium oxide dismutase (SOD) were assessed as indicators of tumor progression. Qualitative tissue response towards the implants and new bone mass formation was histologically investigated. BG20 and BG40, with or without progenitor cells, did not cause organ damage, long-term systemic inflammatory reactions or tumor formation. BG20 and BG40 supported bone formation, which was further enhanced in the presence of EPCs and MSCs. This investigation reflects good biocompatibility of the biomaterials BG20 and BG40 and provides evidence that additionally seeding EPCs and MSCs onto the scaffold does not induce tumor formation. PMID:24498345

  15. Dietary n-3 fatty acids increase spleen size and postendotoxin circulating TNF in mice; role of macrophages, macrophage precursors, and colony-stimulating factor-1.

    PubMed

    Blok, W L; de Bruijn, M F; Leenen, P J; Eling, W M; van Rooijen, N; Stanley, E R; Buurman, W A; van der Meer, J W

    1996-12-15

    In experimental studies in mice, dietary supplementation with n-3 fatty acids (FA) alleviates inflammation and increases resistance to infection. Nevertheless, TNF production capacity was found to be increased in n-3 FA-fed mice. We previously found increased relative spleen weights in n-3 FA-fed mice. In this study, the nature of this increased spleen size was further investigated. Spleen cellularity was increased significantly in mice fed n-3 FA (fish oil 15% w/w), compared with controls fed corn oil (15%) or normal lab chow (p < 0.05). Experiments with T cell-deficient nude mice and experiments using macrophage depletion through liposomal dichloromethylene-biphosphonate revealed that the increase in spleen cellularity is T cell independent and largely due to macrophage accumulation in the spleen. Accumulation of marginal zone and red pulp macrophages was histologically and immunohistochemically confirmed. n-3 FA induced peripheral blood monocytosis and an aspecific increase in bone marrow cellularity. Postendotoxin circulating TNF concentrations were increased significantly in n-3 FA-fed mice compared with controls. Splenectomy did not abolish this increase in circulating TNF. However, after macrophage depletion through liposomal dichloromethylene-biphosphonate, circulating TNF was not detectable after endotoxin challenge. Circulating concentrations of CSF-1 did not differ between the various experimental groups. It is suggested that the cellular changes observed relate to increased constitutive production of TNF.

  16. Agonist-sensitive calcium pool in the pancreatic acinar cell. I. Permeability properties

    SciTech Connect

    Muallem, S.; Schoeffield, M.S.; Fimmel, C.J.; Pandol, S.J.

    1988-08-01

    45Ca2+ fluxes and free cytosolic Ca2+ (( Ca2+)i) were used to describe the Ca2+ permeability and Ca2+ reloading of the agonist-sensitive pool at rest, during stimulation, and at termination of stimulation. A sequence of stimulation with carbachol, inhibition with atropine (cycling), and restimulation with cholecystokinin octapeptide (CCK-8) was used to follow Ca2+ reloading. Reloading of the pool required extracellular Ca2+ and was measured as an increased rate and extent of 45Ca2+ uptake into the acini. The 45Ca2+ incorporated into cycled acini could be completely released with CCK-8. The dose-response curves for 45Ca uptake and release were identical to those of the hormonally evoked (Ca2+)i increase. The increased 45Ca2+ uptake during reloading was not due to an expansion of any intracellular pool size but reflects the labeling of the pool to isotopic equilibrium in cycled acini. The rate constant of Ca2+ efflux from the pool of resting cells was approximately 0.67 +/- 0.01/h. With stimulation, the Ca2+ permeability of the pool membrane rapidly increased, resulting in Ca2+ release into the cytosol and an increase in (Ca2+)i. With termination of stimulation, the Ca2+ permeability of the pool membrane rapidly decreased while the pool continued to reload with extracellular Ca2+. Labeling of the pool to isotopic equilibrium allowed determination of the amount of Ca2+ released from the pool, which was 2.94 +/- 0.06 nmol/mg protein. This indicates that total Ca2+ concentration in the pool is in the millimolar range.

  17. Difficulties with estimating and interpreting species pools and the implcations for understanding patterns of diversity

    USGS Publications Warehouse

    Grace, J.B.

    2001-01-01

    Evidence has been accumulating that species pools play a major role in regulating variations in small-scale diversity. However, our ability to unambiguously estimate and interpret species pools remains a major impediment to understanding the processes that control patterns of diversity. Two main approaches have been employed to evaluate the relationships between species pools and species diversity. The direct approach has been to estimate the actual sizes of species pools by sampling discrete areas at larger spatial scales and then relating these estimates to samples taken at smaller scales. The indirect approach has been to search for correlations between abiotic environmental factors and patterns of diversity that are indicative of gradients in species pools. Both of these approaches have substantial predictive capability but also have limitations that impair our ability to draw unambiguous interpretations about causal factors. A primary difficulty for the direct approach is in deciding which species in the larger pool of potential species are actually capable of living in a sample. In this regard, the indirect approach requires fewer assumptions and has the ability to detect previously unsuspected gradients in species pools. As with the direct approach, assessing the causes for observed gradients in species pools remains a limitation for the indirect approach. Consideration of experimental studies of potential niches suggests that it may be valuable to distinguish between potential and observed species pools if the role of competitive exclusion is to be fully assessed. This paper concludes by arguing for (1) an increased use of multivariate studies that examine the effects of species pools indirectly and (2) further experimental studies designed to determine potential species pools.

  18. An evaluation of population index and estimation techniques for tadpoles in desert pools

    USGS Publications Warehouse

    Jung, Robin E.; Dayton, Gage H.; Williamson, Stephen J.; Sauer, John R.; Droege, Sam

    2002-01-01

    Using visual (VI) and dip net indices (DI) and double-observer (DOE), removal (RE), and neutral red dye capture-recapture (CRE) estimates, we counted, estimated, and censused Couch's spadefoot (Scaphiopus couchii) and canyon treefrog (Hyla arenicolor) tadpole populations in Big Bend National Park, Texas. Initial dye experiments helped us determine appropriate dye concentrations and exposure times to use in mesocosm and field trials. The mesocosm study revealed higher tadpole detection rates, more accurate population estimates, and lower coefficients of variation among pools compared to those from the field study. In both mesocosm and field studies, CRE was the best method for estimating tadpole populations, followed by DOE and RE. In the field, RE, DI, and VI often underestimated populations in pools with higher tadpole numbers. DI improved with increased sampling. Larger pools supported larger tadpole populations, and tadpole detection rates in general decreased with increasing pool volume and surface area. Hence, pool size influenced bias in tadpole sampling. Across all techniques, tadpole detection rates differed among pools, indicating that sampling bias was inherent and techniques did not consistently sample the same proportion of tadpoles in each pool. Estimating bias (i.e., calculating detection rates) therefore was essential in assessing tadpole abundance. Unlike VI and DOE, DI, RE, and CRE could be used in turbid waters in which tadpoles are not visible. The tadpole population estimates we used accommodated differences in detection probabilities in simple desert pool environments but may not work in more complex habitats.

  19. An evaluation of population index and estimation techniques for tadpoles in desert pools

    USGS Publications Warehouse

    Jung, R.E.; Dayton, G.H.; Williamson, S.J.; Sauer, J.R.; Droege, S.

    2002-01-01

    Using visual (VI) and dip net indices (DI) and double-observer (DOE), removal (RE), and neutral red dye capture-recapture (CRE) estimates, we counted, estimated, and censused Couch's spadefoot (Scaphiopus couchii) and canyon treefrog (Hyla arenicolor) tadpole populations in Big Bend National Park, Texas. Initial dye experiments helped us determine appropriate dye concentrations and exposure times to use in mesocosm and field trials. The mesocosm study revealed higher tadpole detection rates, more accurate population estimates, and lower coefficients of variation among pools compared to those from the field study. In both mesocosm and field studies, CRE was the best method for estimating tadpole populations, followed by DOE and RE. In the field, RE, DI, and VI often underestimated populations in pools with higher tadpole numbers. DI improved with increased sampling. Larger pools supported larger tadpole populations, and tadpole detection rates in general decreased with increasing pool volume and surface area. Hence, pool size influenced bias in tadpole sampling. Across all techniques, tadpole detection rates differed among pools, indicating that sampling bias was inherent and techniques did not consistently sample the same proportion of tadpoles in each pool Estimating bias (i.e, calculating detection rates) therefore was essential in assessing tadpole abundance. Unlike VI and DOE, DI, RE, and CRE could be used in turbid waters in which tadpoles are not visible. The tadpole population estimates we used accommodated differences in detection probabilities in simple desert pool environments but may not work in more complex habitats.

  20. Measurements in large pool fires with an actively cooled calorimeter

    SciTech Connect

    Koski, J.A.; Wix, S.D.

    1995-12-31

    The pool fire thermal test described in Safety Series 6 published by the International Atomic Energy Agency (IAEA) or Title 10, Code of Federal Regulations, Part 71 (10CFR71) in the United States is one of the most difficult tests that a container for larger ``Type B`` quantities of nuclear materials must pass. If retests of a container are required, costly redesign and project delays can result. Accurate measurements and modeling of the pool fire environment will ultimately lower container costs by assuring that containers past the pool fire test on the first attempt. Experiments indicate that the object size or surface temperature of the container can play a role in determining local heat fluxes that are beyond the effects predicted from the simple radiative heat transfer laws. An analytical model described by Nicolette and Larson 1990 can be used to understand many of these effects. In this model a gray gas represents soot particles present in the flame structure. Close to the container surface, these soot particles are convectively and radiatively cooled and interact with incident energy from the surrounding fire. This cooler soot cloud effectively prevents some thermal radiation from reaching the container surface, reducing the surface heat flux below the value predicted by a transparent medium model. With some empirical constants, the model suggested by Nicolette and Larson can be used to more accurately simulate the pool fire environment. Properly formulated, the gray gas approaches also fast enough to be used with standard commercial computer codes to analyze shipping containers. To calibrate this type of model, accurate experimental measurements of radiative absorption coefficients, flame temperatures, and other parameters are necessary. A goal of the calorimeter measurements described here is to obtain such parameters so that a fast, useful design tool for large pool fires can be constructed.

  1. 10 CFR 36.33 - Irradiator pools.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... purification system designed to be capable of maintaining the water during normal operation at a conductivity..., irradiator pools must either: (1) Have a water-tight stainless steel liner or a liner metallurgically... water level that could allow water to drain out of the pool. Pipes that have intakes more than 0.5...

  2. A Training Program for Swimming Pool Operators.

    ERIC Educational Resources Information Center

    Pope, James R., Jr.; Mihalik, Brian J.

    1985-01-01

    In the United States today, there is a dramatic shortage of qualified public swimming pool operators. This article describes a training program initiated in South Carolina to serve the needs of everyone responsible for and involved in the safe operation and management of a public swimming pool. (MT)

  3. 21 CFR 1250.89 - Swimming pools.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... types of salt water pools shall be so operated that complete circulation and replacement of the water in... equipped so as to provide complete circulation, replacement, and filtration of the water in the pool every six hours or less. Suitable means of chlorination and, if necessary, other treatment of the...

  4. 10 CFR 36.33 - Irradiator pools.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... purification system designed to be capable of maintaining the water during normal operation at a conductivity..., irradiator pools must either: (1) Have a water-tight stainless steel liner or a liner metallurgically... water level that could allow water to drain out of the pool. Pipes that have intakes more than 0.5...

  5. 21 CFR 1250.89 - Swimming pools.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... types of salt water pools shall be so operated that complete circulation and replacement of the water in... equipped so as to provide complete circulation, replacement, and filtration of the water in the pool every six hours or less. Suitable means of chlorination and, if necessary, other treatment of the...

  6. 21 CFR 1250.89 - Swimming pools.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... types of salt water pools shall be so operated that complete circulation and replacement of the water in... equipped so as to provide complete circulation, replacement, and filtration of the water in the pool every six hours or less. Suitable means of chlorination and, if necessary, other treatment of the...

  7. 21 CFR 1250.89 - Swimming pools.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... types of salt water pools shall be so operated that complete circulation and replacement of the water in... equipped so as to provide complete circulation, replacement, and filtration of the water in the pool every six hours or less. Suitable means of chlorination and, if necessary, other treatment of the...

  8. The Chemistry of Swimming Pool Maintenance

    ERIC Educational Resources Information Center

    Salter, Carl; Langhus, David L.

    2007-01-01

    The study of chemistry involved in the maintenance of a swimming pool provides a lot of chemical education to the students, including the demonstration of the importance of pH in water chemistry. The various chemical aspects hidden in the maintenance of the pool are being described.

  9. LinguisticBelief and PoolEvidence

    SciTech Connect

    DARBY, JOHN

    2008-03-11

    LinguisticBelief allows the creation and analysis of combinations of linguistic variables with epistemic uncertainty for decision making. The model is solved using approximate reasoning to implement the belief/plausibility measure of uncertainty for combinations of variables expressed as purely linguistic fuzzy sets. PoolEvidence pools evidence for linguistic variables from many experts for input into LinguisticBelief.

  10. Atlantic Warm Pool Trigger for the Younger Dryas Climate Event

    NASA Astrophysics Data System (ADS)

    Abdul, N. A.; Mortlock, R. A.; Wright, J. D.; Fairbanks, R. G.; Teneva, L. T.

    2011-12-01

    There is growing evidence that variability in the size and heat content of the tropical Atlantic Warm Pool impacts circum-North Atlantic climate via the Atlantic Multi-decadal Oscillation mode (Wang et al., 2008). The Atlantic Warm Pool spans the Gulf of Mexico, Caribbean Sea and the western tropical North Atlantic. Barbados is located near the center of the tropical Atlantic Warm Pool and coupled ocean models suggest that Barbados remains near the center of the tropical Atlantic Warm Pool under varying wind stress simulations. Measurements of the oxygen isotope paleothermometer in Acropora palmata coral species recovered from cores offshore Barbados, show a 3oC monotonic decrease in sea surface temperature from 13106 ± 83 to 12744 ± 61 years before present (errors given as 2 sigma). This interval corresponds to a sea level rise from 71.4 meters to 67.1 meters below present levels at Barbados. The 3oC temperature decrease is captured in eight A. palmata specimens that are in stratigraphic sequence, 230Th/234U dated, and analyzed for oxygen isotopes. All measurements are replicated. We are confident that this is the warm pool equivalent of the Younger Dryas climate event. The initiation of this temperature drop in the Atlantic Warm Pool predates the Younger Dryas start in Greenland ice cores, reported to start at 12896 ± 138 years (relative to AD 2000) (Rasmussen et al., 2006), while few other Younger Dryas climate records are dated with similar accuracy to make the comparison. Rasmussen, S.O., Andersen, K.K., Svensson, A.M., Steffensen, J.P., Vinther, B.M., Clausen, H.B., Siggaard-Andersen, M.L., Johnsen, S.J., Larsen, L.B., Dahl-Jensen, D., Bigler, M., Röthlisberger, R., Fischer, H., Goto-Azuma, K., Hansson, M.E., and Ruth, U., 2006, A new Greenland ice core chronology for the last glacial termination: J. Geophys. Res., v. 111, p. D06102. Wang, C., Lee, S.-K., and Enfield, D.B., 2008, Atlantic Warm Pool acting as a link between Atlantic Multidecadal

  11. Amino acid transporters: roles in amino acid sensing and signalling in animal cells.

    PubMed Central

    Hyde, Russell; Taylor, Peter M; Hundal, Harinder S

    2003-01-01

    Amino acid availability regulates cellular physiology by modulating gene expression and signal transduction pathways. However, although the signalling intermediates between nutrient availability and altered gene expression have become increasingly well documented, how eukaryotic cells sense the presence of either a nutritionally rich or deprived medium is still uncertain. From recent studies it appears that the intracellular amino acid pool size is particularly important in regulating translational effectors, thus, regulated transport of amino acids across the plasma membrane represents a means by which the cellular response to amino acids could be controlled. Furthermore, evidence from studies with transportable amino acid analogues has demonstrated that flux through amino acid transporters may act as an initiator of nutritional signalling. This evidence, coupled with the substrate selectivity and sensitivity to nutrient availability classically associated with amino acid transporters, plus the recent discovery of transporter-associated signalling proteins, demonstrates a potential role for nutrient transporters as initiators of cellular nutrient signalling. Here, we review the evidence supporting the idea that distinct amino acid "receptors" function to detect and transmit certain nutrient stimuli in higher eukaryotes. In particular, we focus on the role that amino acid transporters may play in the sensing of amino acid levels, both directly as initiators of nutrient signalling and indirectly as regulators of external amino acid access to intracellular receptor/signalling mechanisms. PMID:12879880

  12. Chemical composition and acidity of size-fractionated inorganic aerosols of 2013-14 winter haze in Shanghai and associated health risk of toxic elements

    NASA Astrophysics Data System (ADS)

    Behera, Sailesh N.; Cheng, Jinping; Huang, Xian; Zhu, Qiongyu; Liu, Ping; Balasubramanian, Rajasekhar

    2015-12-01

    The severe winter haze episode that occurred in Shanghai from December 2013 to January 2014, characterized by elevated levels of particulate matter (PM), received considerable international attention because of its impacts on public health and disruption of day-to-day activities. To examine the characteristics of PM during this haze episode and to assess the chemistry behind formation of secondary inorganic aerosols (SIA) and associated health impacts due to exposure of toxic elements, we characterized eight water soluble inorganic (WSI) ions and twenty four trace elements in twelve size-fractionated PM (10 nm-9.9 μm). The average mass concentrations of coarse (1.8 μm < Dp < 9.9 μm), fine (Dp < 2.5 μm), ultrafine (0.01 μm < Dp < 0.10 μm) and nano (0.01 μm < Dp < 0.056 μm) particles during hazy days were 2.8, 5.2, 5.3 and 5.1 times higher than those during non-hazy days, respectively. The in-situ pH (pHIS), as predicted by the Aerosol Inorganic Model (AIM-IV) in all sizes of PM, was observed to be lower during hazy days (average of -0.64) than that during non-hazy days (average of -0.29); there was an increased acidity in haze aerosols. Based on the measured concentrations of particulate-bound toxic elements, health risk assessment was conducted, which revealed that the excess lifetime carcinogenic risk to individuals exposed to fine particles under haze events increased significantly (P < 0.05) to 69 ± 18 × 10-6 compared to non-hazy days (34 ± 10 × 10-6). The qualitative source attribution analysis suggested that the occurrence of haze could be due to a combination of increased emissions of PM from multiple anthropogenic sources followed by its accumulation under unfavourable meteorological conditions with lower mixing heights and less wind speeds and the formation of secondary aerosols.

  13. A comparison of two fecal collection methods for protein and amino acid digestibility coefficients for menhaden fish meal and two grades of pultry-by-product meals in market-size sunshine bass (Morone chrysops X M. saxatilis)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apparent digestibility and availability coefficients for protein and amino acids in menhaden fish meal (MEN), pet-food grade (PBM-pet,) and feed-grade poultry by-product meal (PBM-feed) were determined for market-size (500 g) sunshine bass using passive netting or manual stripping of feces. A refer...

  14. Production of various disinfection byproducts in indoor swimming pool waters treated with different disinfection methods.

    PubMed

    Lee, Jin; Jun, Myung-Jin; Lee, Man-Ho; Lee, Min-Hwan; Eom, Seog-Won; Zoh, Kyung-Duk

    2010-11-01

    In this study, the concentrations of disinfection byproducts (DBPs), including trihalomethanes (THMs; chloroform, bromodichloromethane, dibromochloromethane, and bromoform), haloacetic acids (HAAs; dichloroacetic acid and trichloroacetic acid), haloacetonitriles (HANs; dichloroacetonitrile, trichloroacetonitrile, bromochloroacetonitrile, and dibromoacetonitrile), and chloral hydrate (CH) were measured in 86 indoor swimming pools in Seoul, Korea, treated using different disinfection methods, such as chlorine, ozone and chlorine, and a technique that uses electrochemically generated mixed oxidants (EGMOs). The correlations between DBPs and other environmental factors such as with total organic carbon (TOC), KMnO(4) consumption, free residual chlorine, pH, and nitrate (NO(3)(-)) in the pools were examined. The geometric mean concentrations of total DBPs in swimming pool waters were 183.1±2.5μg/L, 32.6±2.1μg/L, and 139.9±2.4μg/L in pools disinfected with chlorine, ozone/chlorine, and EGMO, respectively. The mean concentrations of total THMs (TTHMs), total HAAs (THAAs), total HANs (THANs), and CH differed significantly depending on the disinfection method used (P<0.01). Interestingly, THAAs concentrations were the highest, followed by TTHMs, CH, and THANs in all swimming pools regardless of disinfection method. TOC showed a good correlation with the concentrations of DBPs in all swimming pools (chlorine; r=0.82, P<0.01; ozone/chlorine; r=0.52, P<0.01, EGMO; r=0.39, P<0.05). In addition, nitrate was positively correlated with the concentrations of total DBPs in swimming pools disinfected with chlorine and ozone/chlorine (chlorine; r=0.58; ozone/chlorine; r=0.60, P<0.01), whereas was negative correlated with the concentrations of total DBPs (r=-0.53, P<0.01) in the EGMO-treated pools.

  15. Exact Length Distribution of Filamentous Structures Assembled from a Finite Pool of Subunits.

    PubMed

    Harbage, David; Kondev, Jané

    2016-07-01

    Self-assembling filamentous structures made of protein subunits are ubiquitous in cell biology. These structures are often highly dynamic, with subunits in a continuous state of flux, binding to and falling off of filaments. In spite of this constant turnover of their molecular parts, many cellular structures seem to maintain a well-defined size over time, which is often required for their proper functioning. One widely discussed mechanism of size regulation involves the cell maintaining a finite pool of protein subunits available for assembly. This finite pool mechanism can control the length of a single filament by having assembly proceed until the pool of free subunits is depleted to the point when assembly and disassembly are balanced. Still, this leaves open the question of whether the same mechanism can provide size control for multiple filamentous structures that are assembled from a common pool of protein subunits, as is often the case in cells. We address this question by solving the steady-state master equation governing the stochastic assembly and disassembly of multifilament structures made from a shared finite pool of subunits. We find that, while the total number of subunits within a multifilament structure is well-defined, individual filaments within the structure have a wide, power-law distribution of lengths. We also compute the phase diagram for two multifilament structures competing for the same pool of subunits and identify conditions for coexistence when both have a well-defined size. These predictions can be tested in cell experiments in which the size of the subunit pool or the number of filament nucleators is tuned.

  16. Micron-sized [6,6]-phenyl C61 butyric acid methyl ester crystals grown by dip coating in solvent vapour atmosphere: interfaces for organic photovoltaics.

    PubMed

    Dabirian, R; Feng, X; Ortolani, L; Liscio, A; Morandi, V; Müllen, K; Samorì, P; Palermo, V

    2010-05-01

    We have devised a novel dip coating procedure to form highly crystalline and macroscopic pi-conjugated architectures on solid surfaces. We have employed this approach to a technologically relevant system, i.e. the electron-acceptor [6,6]-phenyl C61 butyric acid methyl ester molecule (PCBM), which is the most commonly used electron-acceptor in organic photovoltaics. Highly ordered, hexagonal shaped crystals of PCBM, ranging between 1 to 80 mum in diameter and from 20 to 500 nm in thickness, have been grown by dip coating the substrates into a solution containing the fullerene derivative. These crystals have been found to possess a monocrystalline character, to exhibit a hexagonal symmetry and to display micron sized molecularly flat terraces. The crystals have been prepared on a wide variety of surfaces such as SiO(x), silanized SiO(x), Au, graphite, amorphous carbon-copper grids and ITO. Their multiscale characterization has been performed by atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), X-ray diffraction (XRD), optical microscopy, scanning and transmission electron microscopy (SEM, TEM).To test the stability of these electron accepting PCBM crystals, they have been coated with a complementary, electron donor hexa-peri-hexabenzocoronene (HBC) derivative by solution processing from acetone and chloroform-methanol blends. The HBC self assembles in a well-defined network of nanofibers on the PCBM substrate, and the two materials can be clearly resolved by AFM and KPFM.Due to its structural precision on the macroscopic scale, the PCBM crystals appear as ideal interface to perform fundamental photophysical studies in electron-acceptor and -donor blends, as well as workbench for unravelling the architecture vs. function relationship in organic solar cells prototypes.

  17. Influence of a hyperlipidic diet on the composition of the non-membrane lipid pool of red blood cells of male and female rats

    PubMed Central

    Remesar, Xavier; Antelo, Arantxa; Llivina, Clàudia; Albà, Emma; Berdié, Lourdes; Agnelli, Silvia; Arriarán, Sofía; Fernández-López, José Antonio

    2015-01-01

    Background and objectives. Red blood cells (RBC) are continuously exposed to oxidative agents, affecting their membrane lipid function. However, the amount of lipid in RBCs is higher than the lipids of the cell membrane, and includes triacylglycerols, which are no membrane components. We assumed that the extra lipids originated from lipoproteins attached to the cell surface, and we intended to analyse whether the size and composition of this lipid pool were affected by sex or diet. Experimental design. Adult male and female Wistar rats were fed control or cafeteria diets. Packed blood cells and plasma lipids were extracted and analysed for fatty acids by methylation and GC-MS, taking care of not extracting membrane lipids. Results. The absence of ω3-PUFA in RBC extracts (but not in plasma) suggest that the lipids extracted were essentially those in the postulated lipid surface pool and not those in cell membrane. In cells’ extracts, there was a marked depletion of PUFA (and, in general, of insaturation). Fatty acid patterns were similar for all groups studied, with limited effects of sex and no effects of diet in RBC (but not in plasma) fatty acids. Presence of trans fatty acids was small but higher in RBC lipids, and could not be justified by dietary sources. Conclusions. The presence of a small layer of lipid on the RBC surface may limit oxidative damage to the cell outer structures, and help explain its role in the transport of lipophilic compounds. However, there may be other, so far uncovered, additional functions for this lipid pool. PMID:26213652

  18. Apparatus for draining lower drywell pool water into suppresion pool in boiling water reactor

    DOEpatents

    Gluntz, Douglas M.

    1996-01-01

    An apparatus which mitigates temperature stratification in the suppression pool water caused by hot water drained into the suppression pool from the lower drywell pool. The outlet of a spillover hole formed in the inner bounding wall of the suppression pool is connected to and in flow communication with one end of piping. The inlet end of the piping is above the water level in the suppression pool. The piping is routed down the vertical downcomer duct and through a hole formed in the thin wall separating the downcomer duct from the suppression pool water. The piping discharge end preferably has an elevation at or near the bottom of the suppression pool and has a location in the horizontal plane which is removed from the point where the piping first emerges on the suppression pool side of the inner bounding wall of the suppression pool. This enables water at the surface of the lower drywell pool to flow into and be discharged at the bottom of the suppression pool.

  19. Fuzzy Pool Balance: An algorithm to achieve a two dimensional balance in distribute storage systems

    NASA Astrophysics Data System (ADS)

    Wu, Wenjing; Chen, Gang

    2014-06-01

    The limitation of scheduling modules and the gradual addition of disk pools in distributed storage systems often result in imbalances among their disk pools in terms of both disk usage and file count. This can cause various problems to the storage system such as single point of failure, low system throughput and imbalanced resource utilization and system loads. An algorithm named Fuzzy Pool Balance (FPB) is proposed here to solve this problem. The input of FPB is the current file distribution among disk pools and the output is a file migration plan indicating what files are to be migrated to which pools. FPB uses an array to classify the files by their sizes. The file classification array is dynamically calculated with a defined threshold named Tmax that defines the allowed pool disk usage deviations. File classification is the basis of file migration. FPB also defines the Immigration Pool (IP) and Emigration Pool (EP) according to the pool disk usage and File Quantity Ratio (FQR) that indicates the percentage of each category of files in each disk pool, so files with higher FQR in an EP will be migrated to IP(s) with a lower FQR of this file category. To verify this algorithm, we implemented FPB on an ATLAS Tier2 dCache production system. The results show that FPB can achieve a very good balance in both free space and file counts, and adjusting the threshold value Tmax and the correction factor to the average FQR can achieve a tradeoff between free space and file count.

  20. A statistical approach to determining responses to individual peptides from pooled-peptide ELISpot data.

    PubMed

    Ström, Peter; Støer, Nathalie; Borthwick, Nicola; Dong, Tao; Hanke, Tomáš; Reilly, Marie

    2016-08-01

    To investigate in detail the effect of infection or vaccination on the human immune system, ELISpot assays are used to simultaneously test the immune response to a large number of peptides of interest. Scientists commonly use "peptide pools", where, instead of an individual peptide, a test well contains a group of peptides. Since the response from a well may be due to any or many of the peptides in the pool, pooled assays usually need to be followed by confirmatory assays of a number of individual peptides. We present a statistical method that enables estimation of individual peptide responses from pool responses using the Expectation Maximization (EM) algorithm for "incomplete data". We demonstrate the accuracy and precision of these estimates in simulation studies of ELISpot plates with 90 pools of 6 or 7 peptides arranged in three dimensions and three Mock wells for the estimation of background. In analysis of real pooled data from 6 subjects in a HIV-1 vaccine trial, where 199 peptides were arranged in 80 pools if size 9 or 10, our estimates were in very good agreement with the results from individual-peptide confirmatory assays. Compared to the classical approach, we could identify almost all the same peptides with high or moderate response, with less than half the number of confirmatory tests. Our method facilitates efficient use of the information available in pooled ELISpot data to avoid or reduce the need for confirmatory testing. We provide an easy-to-use free online application for implementing the method, where on uploading two spreadsheets with the pool design and pool responses, the user obtains the estimates of the individual peptide responses. PMID:27196788

  1. 10 CFR 36.63 - Pool water purity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Pool water purity. 36.63 Section 36.63 Energy NUCLEAR... § 36.63 Pool water purity. (a) Pool water purification system must be run sufficiently to maintain the conductivity of the pool water below 20 microsiemens per centimeter under normal circumstances. If pool...

  2. 10 CFR 36.63 - Pool water purity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Pool water purity. 36.63 Section 36.63 Energy NUCLEAR... § 36.63 Pool water purity. (a) Pool water purification system must be run sufficiently to maintain the conductivity of the pool water below 20 microsiemens per centimeter under normal circumstances. If pool...

  3. 10 CFR 36.63 - Pool water purity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Pool water purity. 36.63 Section 36.63 Energy NUCLEAR... § 36.63 Pool water purity. (a) Pool water purification system must be run sufficiently to maintain the conductivity of the pool water below 20 microsiemens per centimeter under normal circumstances. If pool...

  4. 48 CFR 9.703 - Contracting with individual pool members.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... individual pool members. 9.703 Section 9.703 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.703 Contracting with individual pool members. (a) Pool members may submit...

  5. 13 CFR 120.1709 - Transfers of Pool Certificates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Transfers of Pool Certificates... Establishment of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1709 Transfers of Pool Certificates. (a) Transfer of Pool Certificates. A Pool Certificate is transferable....

  6. 48 CFR 9.702 - Contracting with pools.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Contracting with pools. 9... PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.702 Contracting with pools. (a) Except as specified in this subpart, a pool shall be treated the same as any...

  7. 48 CFR 9.703 - Contracting with individual pool members.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... individual pool members. 9.703 Section 9.703 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.703 Contracting with individual pool members. (a) Pool members may submit...

  8. 13 CFR 120.1709 - Transfers of Pool Certificates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Transfers of Pool Certificates... Establishment of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1709 Transfers of Pool Certificates. (a) Transfer of Pool Certificates. A Pool Certificate is transferable....

  9. 13 CFR 120.1709 - Transfers of Pool Certificates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Transfers of Pool Certificates... Establishment of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1709 Transfers of Pool Certificates. (a) Transfer of Pool Certificates. A Pool Certificate is transferable....

  10. 48 CFR 9.703 - Contracting with individual pool members.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... individual pool members. 9.703 Section 9.703 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.703 Contracting with individual pool members. (a) Pool members may submit...

  11. 48 CFR 9.702 - Contracting with pools.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Contracting with pools. 9... PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.702 Contracting with pools. (a) Except as specified in this subpart, a pool shall be treated the same as any...

  12. 13 CFR 120.1709 - Transfers of Pool Certificates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Transfers of Pool Certificates... Establishment of SBA Secondary Market Guarantee Program for First Lien Position 504 Loan Pools § 120.1709 Transfers of Pool Certificates. (a) Transfer of Pool Certificates. A Pool Certificate is transferable....

  13. 48 CFR 9.702 - Contracting with pools.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Contracting with pools. 9... PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.702 Contracting with pools. (a) Except as specified in this subpart, a pool shall be treated the same as any...

  14. 48 CFR 9.703 - Contracting with individual pool members.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... individual pool members. 9.703 Section 9.703 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.703 Contracting with individual pool members. (a) Pool members may submit...

  15. 48 CFR 9.702 - Contracting with pools.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Contracting with pools. 9... PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.702 Contracting with pools. (a) Except as specified in this subpart, a pool shall be treated the same as any...

  16. Swimming Pools. A Guide to Their Planning, Design and Operation.

    ERIC Educational Resources Information Center

    Gabrielsen, M. Alexander, Ed.

    Information is presented regarding all phases of swimming pool development and operation from earliest planning considerations to final programing. This comprehensive book covers--(1) the steps involved in planning a pool, (2) designing the pool, (3) water circulation, filtration, and treatment, (4) community pools, school and agency pools, and…

  17. 48 CFR 9.703 - Contracting with individual pool members.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... individual pool members. 9.703 Section 9.703 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.703 Contracting with individual pool members. (a) Pool members may submit...

  18. 48 CFR 9.702 - Contracting with pools.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contracting with pools. 9... PLANNING CONTRACTOR QUALIFICATIONS Defense Production Pools and Research and Development Pools 9.702 Contracting with pools. (a) Except as specified in this subpart, a pool shall be treated the same as any...

  19. Intracellular Metabolite Pool Changes in Response to Nutrient Depletion Induced Metabolic Switching in Streptomyces coelicolor.

    PubMed

    Wentzel, Alexander; Sletta, Havard; Ellingsen, Trond E; Bruheim, Per

    2012-02-17

    A metabolite profiling study of the antibiotic producing bacterium Streptomyces coelicolor A3(2) has been performed. The aim of this study was to monitor intracellular metabolite pool changes occurring as strains of S. coelicolor react to nutrient depletion with metabolic re-modeling, so-called metabolic switching, and transition from growth to secondary metabolite production phase. Two different culture media were applied, providing depletion of the key nutrients phosphate and L-glutamate, respectively, as the triggers for metabolic switching. Targeted GC-MS and LC-MS methods were employed to quantify important primary metabolite groups like amino acids, organic acids, sugar phosphates and other phosphorylated metabolites, and nucleotides in time-course samples withdrawn from fully-controlled batch fermentations. A general decline, starting already in the early growth phase, was observed for nucleotide pools and phosphorylated metabolite pools for both the phosphate and glutamate limited cultures. The change in amino acid and organic acid pools were more scattered, especially in the phosphate limited situation while a general decrease in amino acid and non-amino organic acid pools was observed in the L-glutamate limited situation. A phoP deletion mutant showed basically the same metabolite pool changes as the wild-type strain M145 when cultivated on phosphate limited medium. This implies that the inactivation of the phoP gene has only little effect on the detected metabolite levels in the cell. The energy charge was found to be relatively constant during growth, transition and secondary metabolite production phase. The results of this study and the employed targeted metabolite profiling methodology are directly relevant for the evaluation of precursor metabolite and energy supply for both natural and heterologous production of secondary metabolites in S. coelicolor.

  20. Intracellular Metabolite Pool Changes in Response to Nutrient Depletion Induced Metabolic Switching in Streptomyces coelicolor

    PubMed Central

    Wentzel, Alexander; Sletta, Havard; Consortium, Stream; Ellingsen, Trond E.; Bruheim, Per

    2012-01-01

    A metabolite profiling study of the antibiotic producing bacterium Streptomyces coelicolor A3(2) has been performed. The aim of this study was to monitor intracellular metabolite pool changes occurring as strains of S. coelicolor react to nutrient depletion with metabolic re-modeling, so-called metabolic switching, and transition from growth to secondary metabolite production phase. Two different culture media were applied, providing depletion of the key nutrients phosphate and L-glutamate, respectively, as the triggers for metabolic switching. Targeted GC-MS and LC-MS methods were employed to quantify important primary metabolite groups like amino acids, organic acids, sugar phosphates and other phosphorylated metabolites, and nucleotides in time-course samples withdrawn from fully-controlled batch fermentations. A general decline, starting already in the early growth phase, was observed for nucleotide pools and phosphorylated metabolite pools for both the phosphate and glutamate limited cultures. The change in amino acid and organic acid pools were more scattered, especially in the phosphate limited situation while a general decrease in amino acid and non-amino organic acid pools was observed in the L-glutamate limited situation. A phoP deletion mutant showed basically the same metabolite pool changes as the wild-type strain M145 when cultivated on phosphate limited medium. This implies that the inactivation of the phoP gene has only little effect on the detected metabolite levels in the cell. The energy charge was found to be relatively constant during growth, transition and secondary metabolite production phase. The results of this study and the employed targeted metabolite profiling methodology are directly relevant for the evaluation of precursor metabolite and energy supply for both natural and heterologous production of secondary metabolites in S. coelicolor. PMID:24957373

  1. Pool-riffle Maintenance in Mountain Streams

    NASA Astrophysics Data System (ADS)

    Chartrand, S. M.

    2015-12-01

    Pool-riffles are maintained through a combination of at least several mechanisms that operate and interact over a range of temporal and spatial scales. Velocity or shear reversal is subsumed within several of these mechanisms, however a growing body of work suggests that (1) flow convergence into pools, (2) structuring of riffle crest sediments, and (3) local feedbacks between flood stage bedform evolution and hydrodynamics may be disproportionately important. We additionally propose that temporal and spatial patterns of sediment sorting across pool-riffles may also provide some level of bedform maintenance. A comprehensive understanding of these maintenance mechanisms is needed. We will report results of several flume experiments for autogenic pool-riffles. The experiments examined pool-riffle maintenance processes under variable flood and sediment supply conditions. A focus of our work is to characterize spatial and temporal patterns of pool-riffle sediment sorting, and to examine this in relation to temporal patterns of bedform evolution. The experiments represent a 5:1 scale-model of a prototype reach of a pool-riffle stream located within the University of British Columbia Malcolm Knapp Research Forest, Maple Ridge, BC.

  2. Optimum blending gives best pool octane

    SciTech Connect

    Morris, W.E.

    1986-01-20

    Optimum blending of gasoline components can increase the pool octane by 0.1 to 0.5 numbers. To achieve the optimum octane blending scheme, accurate octane blending values must be obtained. These blending values can be developed from an interaction blending study or from generalized predicted interaction coefficients. Many refiners are blending in a non-optimum fashion so that there are some cheap octanes available for the taking by simply changing to an optimum blending scheme. A study of 1984 gasoline compositions indicated that many refiners were blending in a non-optimum fashion and that ''pool octane'' could have been increased almost 0.5 octane. The term pool octane usually refers to the weighted average octane of all of the gasoline components. It can be calculated by multiplying the octane of each component by its fraction of the pool and adding the results. If the components are blended into two or more grades, a second pool octane could be calculated by multiplying the octane of each grade, before any lead antiknock addition, by its fraction of the total pool. The second pool octane will differ from the first because the components do not blend linearly. The octane of a 50:50 blend of two components may be higher or lower than the average of the octanes of the two components.

  3. Distributed Technologies in a Data Pool

    NASA Astrophysics Data System (ADS)

    Keiser, K.; Conover, H.; Graves, S.; He, Y.; Regner, K.; Smith, M.

    2004-12-01

    A Data Pool is an on-line repository providing interactive and programmatic access to data products through a variety of services. The University of Alabama in Huntsville has developed and deployed such a Data Pool in conjunction with the DISCOVER project, a collaboration with NASA and Remote Sensing Systems. DISCOVER provides long-term ocean and climate data from a variety of passive microwave satellite instruments, including such products as sea-surface temperature and wind, air temperature, atmospheric water vapor, cloud water and rain rate. The Data Pool provides multiple methods to access and visualize these products, including conventional HTTP and FTP access, as well as data services that provide for enhanced usability and interoperability, such as GridFTP, OPeNDAP, OpenGIS-compliant web mapping and coverage services, and custom subsetting and packaging services. This paper will focus on the distributed service technologies used in the Data Pool, which spans heterogeneous machines at multiple locations. For example, in order to provide seamless access to data at multiple sites, the Data Pool provides catalog services for all data products at the various data server locations. Under development is an automated metadata generation tool that crawls the online data repositories regularly to dynamically update the Data Pool catalog with information about newly generated data files. For efficient handling of data orders across distributed repositories, the Data Pool also implements distributed data processing services on the file servers where the data resides. Ontologies are planned to support automated service chaining for custom user requests. The UAH Data Pool is based on a configurable technology framework that integrates distributed data services with a web interface and a set of centralized database services for catalogs and order tracking. While this instantiation of the Data Pool was implemented to meet the needs of the DISCOVER project, the framework was

  4. Intracellular alpha-keto acid quantification by fluorescence-HPLC.

    PubMed

    Fuchs, M; Engel, J; Campos, M; Matejec, R; Henrich, M; Harbach, H; Wolff, M; Weismüller, K; Menges, T; Heidt, M C; Welters, I D; Krüll, M; Hempelmann, G; Mühling, J

    2009-01-01

    Procedures for the analysis of free alpha-keto acids in human fluids (i.e. plasma, cerebrospinal fluid, urine, etc.) as well as for studying the dynamic free alpha-keto acid pools in differentiated tissues and organ cells have been the subject of growing clinical interest in the study of metabolic regulatory and pathophysiological phenomena. Due to the high instability and polarity of the alpha-keto acids being examined, the development of a quantitative and reproducible analysis of metabolically relevant intracellular alpha-keto acids still presents a substantial methodological challenge. The aim of small sample size, rapid, non-damaging and "metabolism-neutral" cell isolation, careful sample preparation and stability, as well as reproducible analytics technology is not often achieved. Only few of the methods described can satisfy the rigorous demands for an ultra-sensitive, comprehensive and rapid intracellular alpha-keto acid analysis.

  5. Longevity of Wood-Forced Pools in an Old-Growth Forest

    NASA Astrophysics Data System (ADS)

    Buffington, J. M.; Woodsmith, R. D.; Johnson, A. C.

    2009-12-01

    Wood debris plays an important role in scouring pools in forest channels and providing resultant habitat for aquatic organisms. We investigated the longevity of such pools in a gravel-bed river flowing through old-growth forest in southeastern Alaska by aging trees and “bear’s bread” fungi (Ganoderma applanatum, Fomitopsis pinicola) growing on pool-forming wood debris. Ages were determined by counting annual growth rings from cores and cross sections of trees and fungi growing on the wood debris. These ages are minimum values because they do not account for lag time between debris recruitment and seedling/spore establishment on the debris, nor do they account for flood scour that may periodically reset tree and fungi growth on the debris. The study stream has a gradient of about 1%, bankfull width and depth of 13.3 and 0.78 m, respectively, median grain size of 18 mm, a high wood loading (0.8 pieces/m), and a correspondingly low pool spacing (0.3 bankfull widths/pool), with 81% of the pools forced by wood debris. The size of wood debris in the study stream is large relative to the channel (average log length of 7.6 m and diameter of 0.35 m), rendering most debris immobile. Eighty-one pool-forming pieces of wood were dated over 1.2 km of stream length, with 28% of these pieces causing scour of more than one pool. In all, 122 wood-forced pools were dated, accounting for 38% of all pools at the site and 47% of the wood-forced pools. Fifty-three percent of the wood-forced pools lacked datable wood because these pieces either: were newly recruited; had been scoured by floods; or were contained below the active channel elevation, prohibiting vegetation establishment on the wood debris (the most common cause). The debris age distribution declined exponentially from 2 to 113 yrs., with a median value of 18 yrs. Similar exponential residence time distributions have been reported in other studies, but our analysis focused specifically on the ages of pool-forming wood

  6. Effects of reduced nitrogen and sulphur deposition on the water chemistry of moorland pools.

    PubMed

    van Kleef, Hein H; Brouwer, Emiel; Leuven, Rob S E W; van Dam, Herman; de Vries-Brock, Ankie; van der Velde, Gerard; Esselink, Hans

    2010-08-01

    To assess changes as a result of reduced acidifying deposition, water chemistry data from 68 Dutch moorland pools were collected during the periods 1983-1984 and 2000-2006. Partial recovery was observed: nitrate- and ammonium-N, sulphur and aluminium concentrations decreased, while pH and alkalinity increased. Calcium and magnesium concentrations decreased. These trends were supported by long term monitoring data (1978-2006) of four pools. Increased pH correlated with increases in orthophosphate and turbidity, the latter due to stronger coloration by organic acids. Increased ortho-phosphate and turbidity are probably the result of stronger decomposition of organic sediments due to decreased acidification and may hamper full recovery of moorland pool communities. In addition to meeting emission targets for NO(x), NH(x) and SO(x), restoration measures are still required to facilitate and accelerate recovery of acidified moorland pools.

  7. Predicting bromide incorporation in a chlorinated indoor swimming pool.

    PubMed

    Chowdhury, Shakhawat; Mazumder, Abu Jafar; Husain, Tahir

    2016-06-01

    The water in and air above swimming pools often contain high levels of disinfection byproducts (DBPs) due to chemical reactions between chlorine- or bromine-based disinfectants and organic/inorganic matter in the source water and released from swimmers. Exposure to these DBPs, though inevitable, can pose health threats to humans. In this study, DBPs in tap water (S1), and water from a chlorinated indoor swimming pool before (S2) and after swimming (S3) were measured. The brominated species constituted the majority of DBPs formed in S1, S2, and S3. Trihalomethanes (THMs) in S3 was 6.9 (range 2.9-11.1) and 1.4 (range 0.52-2.9) times those in S1 and S2, respectively; and the haloacetic acids (HAAs) in S3 was 4.2 (range 2.5-7.5) and 1.2 (range 0.6-2.6) times those in S1 and S2, respectively. The mean THMs in air above the swimming pool before (S2-A) and after swimming (S3-A) were 72.2 and 93.0 μg/m(3), respectively, and their ranges were 36.3-105.8 and 44.1-133.6 μg/m(3), respectively. The average percentages of bromide incorporation (BI) into THMs in S1, S2, and S3 were 3.0, 9.3, and 10.6 %, respectively; and the BI into HAAs in S1, S2, and S3 were 6.6, 12.0, and 12.2 %, respectively. Several models were trained for predicting the BI into THMs and HAAs. The results indicate that additional information is required to develop predictive models for BI in swimming pools.

  8. Two distinct pools of membrane phosphatidylglycerol in Bacillus megaterium

    SciTech Connect

    Lombardi, F.J.; Fulco, A.J.

    1980-02-01

    The predominant membrane lipid in Bacillus megaterium ATCC 14581, phosphatidylglycerol (PG), is present in two distinct pools, as shown by (/sup 32/P)phosphate incorporation and chase experiments. One pool (PG/sub t/) undergoes rapid turnover of the phosphate moiety, whereas the second pool (PG/sub s/) exhibits metabolic stability in this group. The phosphate moiety of the other major phospholipid, phosphatidylethanolamine, is stable to turnover. (/sup 32/P)phosphate- and (2-/sup 3/H)glycerol-equilibrated cultures yielded the following glycerolipid composition: 56 mol% PG (34 mol% PG/sub t/ and 22 mol% PG/sub s/), 21 mol% phosphatidylethanolamine, 1 to 2 mol% phosphatidylserine, 20 mol% diglycerides, less than 0.5 mol% cardiolipin, and 0.2 to 0.4 mol% lysophosphatidylglycerol. Accumulation of PG was halted immediately after the addition of cerulenin, an inhibitor of de novo fatty acid synthesis, whereas phosphatidylethanolamine accumulation continued at the expense of the diglyceride and PG pools. Strikingly, initial rates of (/sup 32/P)phosphate incorporation into PG were unaffected by cerulenin. In control cultures at 35/sup 0/C, incorporation of (/sup 32/P)phosphate into PG exhibited a biphasic time course, whereas incorporation into phosphatidylethanolamine was concave upward and lagged behind that of PG during the initial rapid phase of PG incorporation. Finally, levels of lysophosphatidylglycerolexpanded rapidly after cerulenin addition at 20/sup 0/C, but not at 35/sup 0/C. Moreover, incorporation of (/sup 32/P)phosphate into lysophosphatidylglycerol lagged behind incorporation into PG in both the presence and absence of cerulenin at 20 and 35/sup 0/C.

  9. [Microecology of nuclear reactor pool water].

    PubMed

    Mal'tsev, V N; Saadavi, A; Aĭiad, A; El'gaui, O; Shlip, M

    1996-01-01

    In the course of research it was found that the circulation of pool water through the nuclear reactor core produces a bactericidal effect of microflora due to the influence of radiation of various types. The amount of microbes returns to initial level after 2-4 months after circulation was stopped. Microflora of pool water comprises large amounts of coccus, Gram-positive rods, fungi and a lower content of Gram-negative rods if compared to water which had been used to fill reactor pool. No difference in radioresistance was noticed for unitype microbes isolated from initial water and from reactor pool water. Quality of microflora reflects a unique phenomenon called "selection" which results in vanishing of all the radiosensitive types of microbes and survival of the radioresistant types. Radioresistance grows with increasing of catalase and nuclease activity.

  10. Pooled genomic indexing of rhesus macaque

    PubMed Central

    Milosavljevic, Aleksandar; Harris, Ronald A.; Sodergren, Erica J.; Jackson, Andrew R.; Kalafus, Ken J.; Hodgson, Anne; Cree, Andrew; Dai, Weilie; Csuros, Miklos; Zhu, Baoli; de Jong, Pieter J.; Weinstock, George M.; Gibbs, Richard A.

    2005-01-01

    Pooled genomic indexing (PGI) is a method for mapping collections of bacterial artificial chromosome (BAC) clones between species by using a combination of clone pooling and DNA sequencing. PGI has been used to map a total of 3858 BAC clones covering ∼24% of the rhesus macaque (Macaca mulatta) genome onto 4178 homologous loci in the human genome. A number of intrachromosomal rearrangements were detected by mapping multiple segments within the individual rhesus BACs onto multiple disjoined loci in the human genome. Transversal pooling designs involving shuffled BAC arrays were employed for robust mapping even with modest DNA sequence read coverage. A further innovation, short-tag pooled genomic indexing (ST-PGI), was also introduced to further improve the economy of mapping by sequencing multiple, short, mapable tags within a single sequencing reaction. PMID:15687293

  11. Investigations in Marine Chemistry: Tide Pool Ecology.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.

    Students investigated the salinity of tide pools at different levels in the intertidal zone. Data are analyzed collectively. Students graphed and discussed data. Included are suggestions for evaluation and further study. (Author)

  12. Profit pools: a fresh look at strategy.

    PubMed

    Gadiesh, O; Gilbert, J L

    1998-01-01

    In charting strategy, many managers focus on revenue growth, assuming that profits will follow. But that approach is dangerous: today's deep revenue pool may become tomorrow's dry hole. To create strategies that result in profitable growth, managers need to look beyond revenues to see the shape of their industry's profit pool. The authors define an industry's profit pool as the total profits earned at all points along the industry's value chain. Although the concept is simple, the structure of a profit pool is usually quite complex. The pool will be deeper in some segments of the value chain than in others, and depths will vary within an individual segment as well. Segment profitability may, for example, vary widely by customer group, product category, geographic market, and distribution channel. Moreover, the pattern of profit concentration in an industry will often be very different from the pattern of revenue concentration. The authors describe how successful companies have gained competitive advantage by developing sophisticated profit-pool strategies. They explain how U-Haul identified new sources of profit in the consumer-truck-rental industry; how Merck reached beyond its traditional value-chain role to protect its profits in the pharmaceuticals industry; how Dell rebounded from a misguided channel decision by refocusing on its traditional source of profit; and how Anheuser-Busch made a series of astute product, pricing, and operating decisions to dominate the beer industry's profit pool. The companies with the best understanding of their industry's profit pool, the authors argue, will be in the best position to thrive over the long term.

  13. Welding pool measurement using thermal array sensor

    NASA Astrophysics Data System (ADS)

    Cho, Chia-Hung; Hsieh, Yi-Chen; Chen, Hsin-Yi

    2015-08-01

    Selective laser melting (SLM) is an additive manufacturing (AM) technology that uses a high-power laser beam to melt metal powder in chamber of inert gas. The process starts by slicing the 3D CAD data as a digital information source into layers to create a 2D image of each layer. Melting pool was formed by using laser irradiation on metal powders which then solidified to consolidated structure. In a selective laser melting process, the variation of melt pool affects the yield of a printed three-dimensional product. For three dimensional parts, the border conditions of the conductive heat transport have a very large influence on the melt pool dimensions. Therefore, melting pool is an important behavior that affects the final quality of the 3D object. To meet the temperature and geometry of the melting pool for monitoring in additive manufacturing technology. In this paper, we proposed the temperature sensing system which is composed of infrared photodiode, high speed camera, band-pass filter, dichroic beam splitter and focus lens. Since the infrared photodiode and high speed camera look at the process through the 2D galvanometer scanner and f-theta lens, the temperature sensing system can be used to observe the melting pool at any time, regardless of the movement of the laser spot. In order to obtain a wide temperature detecting range, 500 °C to 2500 °C, the radiation from the melting pool to be measured is filtered into a plurality of radiation portions, and since the intensity ratio distribution of the radiation portions is calculated by using black-body radiation. The experimental result shows that the system is suitable for melting pool to measure temperature.

  14. Electromagnetic Interference in a Private Swimming Pool

    PubMed Central

    Iskandar, Sandia; Lavu, Madhav; Atoui, Moustapha; Lakkireddy, Dhanunjaya

    2016-01-01

    Although current lead design and filtering capabilities have greatly improved, Electromagnetic Interference (EMI) from environmental sources has been increasingly reported in patients with Cardiac Implantable Electronic Device (CIED) [1]. Few cases of inappropriate intracardiac Cardioverter Defibrillator (ICD) associated with swimming pool has been described [2]. Here we present a case of 64 year old male who presented with an interesting EMI signal that was subsequently identified to be related to AC current leak in his swimming pool. PMID:27479205

  15. Neural Network Modeling of Weld Pool Shape in Pulsed-Laser Aluminum Welds

    SciTech Connect

    Iskander, Y.S.; Oblow, E.M.; Vitek, J.M.

    1998-11-16

    A neural network model was developed to predict the weld pool shape for pulsed-laser aluminum welds. Several different network architectures were examined and the optimum architecture was identified. The neural network was then trained and, in spite of the small size of the training data set, the network accurately predicted the weld pool shape profiles. The neural network output was in the form of four weld pool shape parameters (depth, width, half-width, and area) and these were converted into predicted weld pool profiles with the use of the actual experimental poo1 profiles as templates. It was also shown that the neural network model could reliably predict the change from conduction-mode type shapes to keyhole-mode shapes.

  16. A fractal study for nucleate pool boiling heat transfer of nanofluids

    NASA Astrophysics Data System (ADS)

    Xiao, Boqi; Jiang, Guoping; Chen, Lingxia

    2010-01-01

    In this paper, a fractal model for nucleate pool boiling heat transfer of nanofluids is developed based on the fractal distribution of nanoparticles and nucleation sites on boiling surfaces. The model shows the dependences of the heat flux on nanoparticle size and the nanoparticle volume fraction of the suspension, the fractal dimension of the nanoparticle and nucleation site, temperature of nanofluids and properties of fluids. The fractal model predictions show that the natural convection stage continues relatively longer in the case of nanofluids. The addition of nanoparticles causes a decrease of the pool nucleate boiling heat transfer. The nucleate pool boiling heat transfer coefficient is decreased by increasing particle concentration. An excellent agreement between the proposed model predictions and experimental data is found. The validity of the fractal model for nucleate pool boiling heat transfer is thus verified.

  17. Occurrence and health risk assessment of halogenated disinfection byproducts in indoor swimming pool water.

    PubMed

    Hang, Chen; Zhang, Beibei; Gong, Tingting; Xian, Qiming

    2016-02-01

    Swimming pool disinfection byproducts (DBPs) have become a concern in many countries all over the world. In this study, the concentrations of several categories of DBPs, including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs) and trichloronitromethane (TCNM), in 13 public indoor swimming pools in Nanjing, China were determined, the correlations between DBPs and water quality parameters as well as between different DBP categories were evaluated, and the health risks of the DBPs to human were examined. The results indicate that the DBP levels in the swimming pools in Nanjing were relatively high, with HAAs as the most dominant category, followed by THMs, HANs, HKs and TCNM sequentially. Bromochloroacetic acid (BCAA), trichloromethane (TCM), dichloroacetonitrile (DCAN), and 1,1,1-trichloropropanone (1,1,1-TCP) were the most dominant species among HAAs, THMs, HANs, and HKs, respectively. For all the different categories of DBPs, the concentrations in the pool disinfected with ozonation/chlorination were lower than those in the pool disinfected with chlorination. The DBP levels were generally not affected by the number of swimmers and the DBP levels on different dates were relatively stable. Besides, the chlorine residual seemed to be a critical concern in most of the swimming pools in this study. Moreover, there were some correlations between DBPs and water quality parameters as well as between different DBP categories. It is to be noted that the predicted cancer and health risks of the DBPs in these swimming pools were generally higher than the regulatory limits by USEPA, and thus DBPs in these swimming pools should be concerned.

  18. Metabolic effects of intestinal absorption and enterohepatic cycling of bile acids

    PubMed Central

    Ferrebee, Courtney B.; Dawson, Paul A.

    2015-01-01

    The classical functions of bile acids include acting as detergents to facilitate the digestion and absorption of nutrients in the gut. In addition, bile acids also act as signaling molecules to regulate glucose homeostasis, lipid metabolism and energy expenditure. The signaling potential of bile acids in compartments such as the systemic circulation is regulated in part by an efficient enterohepatic circulation that functions to conserve and channel the pool of bile acids within the intestinal and hepatobiliary compartments. Changes in hepatobiliary and intestinal bile acid transport can alter the composition, size, and distribution of the bile acid pool. These alterations in turn can have significant effects on bile acid signaling and their downstream metabolic targets. This review discusses recent advances in our understanding of the inter-relationship between the enterohepatic cycling of bile acids and the metabolic consequences of signaling via bile acid-activated receptors, such as farnesoid X nuclear receptor (FXR) and the G-protein-coupled bile acid receptor (TGR5). PMID:26579438

  19. Characterisation of the Permafrost Carbon Pool

    USGS Publications Warehouse

    Kuhry, P.; Grosse, G.; Harden, J.W.; Hugelius, G.; Koven, C.D.; Ping, C.-L.; Schirrmeister, L.; Tarnocai, C.

    2013-01-01

    The current estimate of the soil organic carbon (SOC) pool in the northern permafrost region of 1672 Petagrams (Pg) C is much larger than previously reported and needs to be incorporated in global soil carbon (C) inventories. The Northern Circumpolar Soil Carbon Database (NCSCD), extended to include the range 0–300 cm, is now available online for wider use by the scientific community. An important future aim is to provide quantitative uncertainty ranges for C pool estimates. Recent studies have greatly improved understanding of the regional patterns, landscape distribution and vertical (soil horizon) partitioning of the permafrost C pool in the upper 3 m of soils. However, the deeper C pools in unconsolidated Quaternary deposits need to be better constrained. A general lability classification of the permafrost C pool should be developed to address potential C release upon thaw. The permafrost C pool and its dynamics are beginning to be incorporated into Earth System models, although key periglacial processes such as thermokarst still need to be properly represented to obtain a better quantification of the full permafrost C feedback on global climate change.

  20. Pool Boiling Experiment Has Five Successful Flights

    NASA Technical Reports Server (NTRS)

    Chiaramonte, Fran

    1997-01-01

    The Pool Boiling Experiment (PBE) is designed to improve understanding of the fundamental mechanisms that constitute nucleate pool boiling. Nucleate pool boiling is a process wherein a stagnant pool of liquid is in contact with a surface that can supply heat to the liquid. If the liquid absorbs enough heat, a vapor bubble can be formed. This process occurs when a pot of water boils. On Earth, gravity tends to remove the vapor bubble from the heating surface because it is dominated by buoyant convection. In the orbiting space shuttle, however, buoyant convection has much less of an effect because the forces of gravity are very small. The Pool Boiling Experiment was initiated to provide insight into this nucleate boiling process, which has many earthbound applications in steamgeneration power plants, petroleum plants, and other chemical plants. In addition, by using the test fluid R-113, the Pool Boiling Experiment can provide some basic understanding of the boiling behavior of cryogenic fluids without the large cost of an experiment using an actual cryogen.

  1. Pool Boiling Experiment Has Successful Flights

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Pool Boiling Experiment (PBE) is designed to improve understanding of the fundamental mechanisms that constitute nucleate pool boiling. Nucleate pool boiling is a process wherein a stagnant pool of liquid is in contact with a surface that can supply heat to the liquid. If the liquid absorbs enough heat, a vapor bubble can be formed. This process occurs when a pot of water boils. On Earth, gravity tends to remove the vapor bubble from the heating surface because it is dominated by buoyant convection. In the orbiting space shuttle, however, buoyant convection has much less of an effect because the forces of gravity are very small. The Pool Boiling Experiment was initiated to provide insight into this nucleate boiling process, which has many Earthbound applications, such as steam-generation power plants, petroleum, and other chemical plants. Also, by using the test fluid R-113, the Pool Boiling Experiment can provide some basic understanding of the boiling behavior of cryogenic fluids without the large cost of an experiment using an actual cryogen.

  2. Disentangling pooled triad genotypes for association studies.

    PubMed

    Shi, Min; Umbach, David M; Weinberg, Clarice R

    2014-09-01

    Association studies that genotype affected offspring and their parents (triads) offer robustness to genetic population structure while enabling assessments of maternal effects, parent-of-origin effects, and gene-by-environment interaction. We propose case-parents designs that use pooled DNA specimens to make economical use of limited available specimens. One can markedly reduce the number of genotyping assays required by randomly partitioning the case-parent triads into pooling sets of h triads each and creating three pools from every pooling set, one pool each for mothers, fathers, and offspring. Maximum-likelihood estimation of relative risk parameters proceeds via log-linear modeling using the expectation-maximization algorithm. The approach can assess offspring and maternal genetic effects and accommodate genotyping errors and missing genotypes. We compare the power of our proposed analysis for testing offspring and maternal genetic effects to that based on a difference approach and that of the gold standard based on individual genotypes, under a range of allele frequencies, missing parent proportions, and genotyping error rates. Power calculations show that the pooling strategies cause only modest reductions in power if genotyping errors are low, while reducing genotyping costs and conserving limited specimens.

  3. Investigation of the Biogenic Origin of Cave Pool Precipitates in the Guadalupe Mountains, NM Using Extracted Phospholipids and Other Biomarkers

    NASA Astrophysics Data System (ADS)

    Kooser, A. S.; Crossey, L.; Northup, D.; Spilde, M.; Melim, L.

    2008-12-01

    Biomarker analysis is an important tool for understanding biogenic carbonates. Past and present bacterial communities utilize chemical species present in the cave environments for metabolic processes and may directly or indirectly contribute to carbonate production. Paleo-communities of bacteria are preserved in speleothems (cave formations) called pool fingers. These speleothems range from 1-4 cm in diameter, 5- 50cm in length and contain alternating layers of micritic calcite and dog tooth spar. The outer portion of the finger can have a moonmilk coating. Pool fingers contain fossilized microbes that can be seen using scanning electron microscopy on etch samples. The lithified communities also leave behind fingerprints in the form of biomarkers. The biomarkers are extracted from pool fingers using a series of solvent washes; the products of each wash are analyzed using gas chromatography followed by gas chromatography/mass spectroscopy. Six samples including pool spar (abiotic speleothem) were examined using this technique. The moonmilk portion of the large pool finger from Cottonwood Cave contained several short-chained fatty acids (C16-C22), which are of microbial origin. In the polar fraction unknown hopanes were detected. The presence of a hopanes with short-chained fatty acids confirms the presence of bacterial biomarkers in the moonmilk portion of the pool finger. The pool spar sample (assumed to be abiotic) produced a different mass spectral pattern for the acid fraction and polar fraction. The acid fraction contains short-chain fatty acids (C16-22), but there are no hopanes present in the other fractions. The polar fraction for the polar spar is dominated by plant biomarkers producing the 'rainbow' spectra of C22 and higher chains. The pool finger, which is thought to be partially biogenic, contains both fossilized bacteria and bacteria biomarkers while the pool spar contains general biomarkers and plant biomarkers. The plant biomarkers found in the pool

  4. Gene-diet interactions with polymorphisms of the MGLL gene on plasma low-density lipoprotein cholesterol and size following an omega-3 polyunsaturated fatty acid supplementation: a clinical trial

    PubMed Central

    2014-01-01

    Background Omega-3 (n-3) polyunsaturated fatty acid (PUFA) consumption increases low-density lipoprotein (LDL) cholesterol (C) concentrations and particle size. Studies showed that individuals with large, buoyant LDL particles have decreased risk of cardiovascular diseases. However, a large inter-individual variability is observed in LDL particle size. Genetic factors may explain the variability of LDL-C concentrations and particle size after an n-3 PUFA supplementation. The monoglyceride lipase (MGLL) enzyme, encoded by the MGLL gene, plays an important role in lipid metabolism, especially lipoprotein metabolism. The aim of this study was to investigate if polymorphisms (SNPs) of the MGLL gene influence the variability of LDL-C and LDL particle size in response to an n-3 PUFA supplementation. Methods 210 subjects completed the study. They consumed 5 g/d of a fish oil supplement (1.9-2.2 g eicosapentaenoic acid and 1.1 g docosaexaenoic acid) during 6 weeks. Plasma lipids were measured before and after the supplementation period and 18 SNPs of the MGLL gene, covering 100% of common genetic variations (minor allele frequency ≥0.05), have been genotyped using TaqMan technology (Life Technologies Inc., Burlington, ON, CA). Results Following the n-3 PUFA supplementation, 55% of subjects increased their LDL-C levels. In a model including the supplementation, genotype and supplementation*genotype effects, gene-diet interaction effects on LDL-C concentrations (rs782440, rs6776142, rs555183, rs6780384, rs6787155 and rs1466571) and LDL particle size (rs9877819 and rs13076593) were observed for the MGLL gene SNPs (p < 0.05). Conclusion SNPs within the MGLL gene may modulate plasma LDL-C levels and particle size following an n-3 PUFA supplementation. This trial was registered at clinicaltrials.gov as NCT01343342. PMID:24884512

  5. Regulation of power pools and system operators: An international comparison

    SciTech Connect

    Barker, J. Jr.; Tenenbaum, B.; Woolf, F.

    1997-12-31

    This paper focuses on the governance and regulation of power pools outside the United States. The current governance and regulatory arrangements for four power pools, as developed in pool documents and government regulations and laws, are compared and contrasted. The power pools analyzed are located in England and Wales, Australia, Canada, and Scandinavia. Topics discussed in relation to these pools are the effects of structure on governance, how each pool has dealt with a number of basic governance decisions, how the pools monitor the markets, ways in which regulators and other institutions control pools, and self-governance issues.

  6. Synthesis of silver nanocubes with controlled size using water-soluble poly(amic acid) salt as the intermediate via a novel ion-exchange self-assembly technique.

    PubMed

    Qi, Shengli; Shen, Xiangyue; Lin, Zhiwei; Tian, GuoFeng; Wu, Dezhen; Jin, Riguang

    2013-12-21

    Here, we report for the first time on the successful fabrication of monodispersed silver nanocubes with regular shape and controlled size in the solid phase via a novel ion-exchange self-assembly technique by using water-soluble poly(amic acid) salt as the intermediate and silver nitrate as the metal precursor. By simply altering the annealing times at high temperature, the size of the silver nanocubes could be finely tuned in the range of 90-160 nm in the present case. Further attempts with different metal salts show that the present method is also feasible for other metal species and might be universal.

  7. Ultrafine aerosol size distributions and sulfuric acid vapor pressures: Implications for new particle formation in the atmosphere. Year 2 progress report

    SciTech Connect

    McMurry, P.H.

    1993-07-01

    This project has two components: (1) measurement of H{sub 2}SO{sub 4} vapor pressures in air under temperature/relative humidity conditions similar to atmospheric, and (2) measurement of ultrafine aerosol size distributions. During Year 2, more effort was put on size distribution measurements. 4 figs.

  8. Local Scouring Geometry in Steep Channels with Grade-Control Structures: Comparison with Natural Pools and Step-Pools Morphology Features

    NASA Astrophysics Data System (ADS)

    Lenzi, M. A.; Comiti, F.; Andreoli, A.

    2002-12-01

    A comparison of the local scouring characteristics below both natural steps (in streams with pools units and step-pool sequences) and grade-control structures has been carried out in 11 mountain streams located in the Eastern Italian Alps. 122 scour holes geometry characteristics of 43 natural pools and below 79 grade-control structures (check-dams, bed sills and boulder check-dams) have been surveyed during summer 2001. 19 parameters representative of the scour holes geometry, grain size and hydraulic boundary conditions have been surveyed or evaluated. The measured features (see Fig. 1) are maximum scour depth ys and the corresponding distance from the step, sill or check-dam lmax; scour length ls; drop height z and particle size at the pool bottom Dp; distance sill-berm lb; distance between natural steps, Lstep or between grade-control structures, Lgcs; longitudinal and ultimate or equilibrium channel slope, S and Seq; pool slope out Sris; banckfull discharge width B; particle size of the forming steps Ds; number of clasts of the forming steps Ns. The most likely formative water discharge is used to evaluated jet thickness at each structure (hc), which along with drop height (z) appears to determine scour hole dimensions, as shown by the consistent trends observed for non-dimensional plots of both maximum scour depth (ys/hc) and length (ls/hc) versus the respective drop ratio(z/hc). Sediment differences regarding size and lithology apparently play a minor role in determining scour hole dimension. Measured maximum scour depths are well predicted by a semi-empirical equation developed through laboratory results, showing an average relative error of 0,14. Jet impinging inclination play an important role on the scour form, particularly in the definition of the maximum scour length; ls increases with both hc and z. In order to analyse the hypothesis that natural pools and scouring geometry below graded-control structures presents features and forms analogy a series

  9. Experimental study of radiant-heat blocking function of fine water mist suppressing small-scale pool fire

    NASA Astrophysics Data System (ADS)

    Xu, Qiang

    2004-04-01

    Fine water mist with droplet diameter less than 20 microns is less studied in water mist family used as firefighting agent. Experiments were conducted to study the radiant heat blocking function of fine water mist in suppressing pool fire. The fine water mist was generated by a jet atomizer. The jet flow of mist was with low momentum when it exerted on the pool fire. The interaction of this kind of fine water mist with pool fire is quite different from those mists with large droplet size and momentum. A group of ethyl-alcohol and gasoline pool fires with different power is used in the research. Fine water mist was exerted on the pool fire from different distances. Radiant heat flux was measured before and after the mist application. The experiment results show that because of its small droplet size and low momentum, the fine water mist could not even penetrate the buoyant plum zone of relatively larger scale pool fire. No water mist could reach the surface of the flame and result in no radiant heat blocking function would realize in the flame zone. This function is valid in low power pool fire and this limitation is obtained from the research for the studied pool fire.

  10. How cold pool triggers deep convection?

    NASA Astrophysics Data System (ADS)

    Yano, Jun-Ichi

    2014-05-01

    The cold pool in the boundary layer is often considered a major triggering mechanism of convection. Here, presented are basic theoretical considerations on this issue. Observations suggest that cold pool-generated convective cells is available for shallow maritime convection (Warner et al. 1979; Zuidema et al. 2012), maritime deep convection (Barnes and Garstang 1982; Addis et al. 1984; Young et al. 1995) and continental deep convection (e.g., Lima and Wilson 2008; Flamant 2009; Lothon et al. 2011; Dione et al. 2013). Moreover, numerical studies appear to suggest that cold pools promote the organization of clouds into larger structures and thereby aid the transition from shallow to deep convection (Khairoutdinov and Randall 2006, Boing et al. 2012, Schlemmer and Hohenegger, 2014). Even a cold--pool parameterization coupled with convection is already proposed (Grandpeix and Lafore 2010: but see also Yano 2012). However, the suggested link between the cold pool and deep convection so far is phenomenological at the best. A specific process that the cold pool leads to a trigger of deep convection must still to be pinned down. Naively, one may imagine that a cold pool lifts up the air at the front as it propagates. Such an uplifting leads to a trigger of convection. However, one must realize that a shift of air along with its propagation does not necessarily lead to an uplifting, and even if it may happen, it would not far exceed a depth of the cold pool itself. Thus, the uplifting can never be anything vigorous. Its thermodynamic characteristics do help much either for inducing convection. The cold-pool air is rather under rapid recovering process before it can induce convection under a simple parcel-lifting argument. The most likely reason that the cold pool may induce convection is its gust winds that may encounter an air mass from an opposite direction. This induces a strong convergence, also leading to a strong uplifting. This is an argument essentially developed

  11. Impact of Inhibiting Ileal Apical Versus Basolateral Bile acid Transport on Cholesterol Metabolism and Atherosclerosis in Mice

    PubMed Central

    Dawson, Paul A.

    2015-01-01

    Background Bile acid sequestrants have been used for many years to treat hypercholesterolemia by increasing hepatic conversion of cholesterol to bile acids, thereby inducing hepatic LDL receptor expression and clearance of apoB-containing particles. In order to further understand the underlying molecular mechanisms linking gut-liver signaling and cholesterol homeostasis, mouse models defective in ileal apical membrane bile acid transport (Asbt null) and ileal basolateral membrane bile acid transport (Ostα null) were studied under basal and hypercholesterolemic conditions. Key Messages Hepatic conversion of cholesterol to bile acids is the major pathway for cholesterol catabolism and a major mechanism for cholesterol elimination. Blocking ileal apical membrane bile acid transport (Asbt null mice) increases fecal bile acid excretion, hepatic Cyp7a1 expression and the relative proportion of taurocholate in the bile acid pool, but decreases ileal FGF15 expression, bile acid pool size, and hepatic cholesterol content. In contrast, blocking ileal basolateral membrane bile acid transport (Ostα null mice) increases ileal FGF15 expression, reduces hepatic Cyp7a1 expression, and increases the proportion of tauro-β-muricholic acid in the bile acid pool. In the hypercholesterolemic apoE null background, plasma cholesterol levels and measurements of atherosclerosis were reduced in Asbt/apoE null mice but not in Ostα/apoE null mice. Conclusions Blocking intestinal absorption of bile acids at the apical versus basolateral membrane differentially affects bile acid and cholesterol metabolism, including the development of hypercholesterolemia-associated atherosclerosis. The molecular mechanism likely involves altered regulation of ileal FGF15 expression. PMID:26045273

  12. Coupling dynamic blow down and pool evaporation model for LNG.

    PubMed

    Woodward, John L

    2007-02-20

    Treating the dynamic effects of accidental discharges of liquefied natural gas (LNG) is important for realistic predictions of pool radius. Two phenomena have important influence on pool spread dynamics, time-varying discharge (blow down) and pool ignition. Time-varying discharge occurs because a punctured LNG tanker or storage tank drains with a decreasing liquid head and decreasing head-space pressure. Pool ignition increases the evaporation rate of a pool and consequently decreases the ultimate pool area. This paper describes an approach to treat these phenomena in a dynamic pool evaporation model. The pool evaporation model developed here has two separate regimes. Early in the spill, momentum forces dominate and the pool spreads independently of pool evaporation rate and the corresponding heat transfer rate. After the average pool depth drops below a minimum value, momentum forces are largely dissipated and the thin edges of the pool completely evaporate, so pool area is established by the heat transfer rate. The maximum extent of a burning pool is predicted to be significantly less than that of an unignited pool because the duration of the first regime is reduced by higher heat transfer rates. The maximum extent of an LNG pool is predicted to be larger upon accounting for blow down compared with using a constant average discharge rate. However, the maximum pool extent occurs only momentarily before retreating. PMID:17184912

  13. Synthesis of silver nanocubes with controlled size using water-soluble poly(amic acid) salt as the intermediate via a novel ion-exchange self-assembly technique

    NASA Astrophysics Data System (ADS)

    Qi, Shengli; Shen, Xiangyue; Lin, Zhiwei; Tian, Guofeng; Wu, Dezhen; Jin, Riguang

    2013-11-01

    Here, we report for the first time on the successful fabrication of monodispersed silver nanocubes with regular shape and controlled size in the solid phase via a novel ion-exchange self-assembly technique by using water-soluble poly(amic acid) salt as the intermediate and silver nitrate as the metal precursor. By simply altering the annealing times at high temperature, the size of the silver nanocubes could be finely tuned in the range of 90-160 nm in the present case. Further attempts with different metal salts show that the present method is also feasible for other metal species and might be universal.Here, we report for the first time on the successful fabrication of monodispersed silver nanocubes with regular shape and controlled size in the solid phase via a novel ion-exchange self-assembly technique by using water-soluble poly(amic acid) salt as the intermediate and silver nitrate as the metal precursor. By simply altering the annealing times at high temperature, the size of the silver nanocubes could be finely tuned in the range of 90-160 nm in the present case. Further attempts with different metal salts show that the present method is also feasible for other metal species and might be universal. Electronic supplementary information (ESI) available: SEM images for the CuO, NiO and Co3O4 nanocubes prepared by the ion-exchange self-assembly technique by using CuCl2, NiSO4 and Co(NO3)2 as the metal precursors and PMDA/ODA-based water-soluble poly(amic acid) salt as the intermediate (Fig. S1-S3) TGA, DSC and DMTA analyses for the pure poly(amic acid) salt and that loaded with 1 mol% silver(i) (Fig. S4-S6). See DOI: 10.1039/c3nr03212d

  14. Class Size.

    ERIC Educational Resources Information Center

    Ellis, Thomas I.

    1985-01-01

    After a brief introduction identifying current issues and trends in research on class size, this brochure reviews five recent studies bearing on the relationship of class size to educational effectiveness. Part 1 is a review of two interrelated and highly controversial "meta-analyses" or statistical integrations of research findings on class size,…

  15. Differential regulation of bile acid and cholesterol metabolism by the farnesoid X receptor in Ldlr -/- mice versus hamsters.

    PubMed

    Gardès, Christophe; Chaput, Evelyne; Staempfli, Andreas; Blum, Denise; Richter, Hans; Benson, G Martin

    2013-05-01

    Modulating bile acid synthesis has long been considered a good strategy by which to improve cholesterol homeostasis in humans. The farnesoid X receptor (FXR), the key regulator of bile acid synthesis, was, therefore, identified as an interesting target for drug discovery. We compared the effect of four, structurally unrelated, synthetic FXR agonists in two fat-fed rodent species and observed that the three most potent and selective agonists decreased plasma cholesterol in LDL receptor-deficient (Ldlr (-/-)) mice, but none did so in hamsters. Detailed investigation revealed increases in the expression of small heterodimer partner (Shp) in their livers and of intestinal fibroblast growth factor 15 or 19 (Fgf15/19) in mice only. Cyp7a1 expression and fecal bile acid (BA) excretion were strongly reduced in mice and hamsters by all four FXR agonists, whereas bile acid pool sizes were reduced in both species by all but the X-Ceptor compound in hamsters. In Ldlr (-/-) mice, the predominant bile acid changed from cholate to the more hydrophilic β-muricholate due to a strong repression of Cyp8b1 and increase in Cyp3a11 expression. However, FXR agonists caused only minor changes in the expression of Cyp8b1 and in bile acid profiles in hamsters. In summary, FXR agonist-induced decreases in bile acid pool size and lipophilicity and in cholesterol absorption and synthesis could explain the decreased plasma cholesterol in Ldlr (-/-) mice. In hamsters, FXR agonists reduced bile acid pool size to a smaller extent with minor changes in bile acid profile and reductions in sterol absorption, and consequently, plasma cholesterol was unchanged.

  16. Metabolic regulation of amino acid uptake in marine waters

    SciTech Connect

    Kirchman, D.L.; Hodson, R.E.

    1986-03-01

    To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal waters of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In waters with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. Marine bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by marine bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis.

  17. Evidence for size and charge permselectivity of rat ascending colon. Effects of ricinoleate and bile salts on oxalic acid and neutral sugar transport.

    PubMed Central

    Kathpalia, S C; Favus, M J; Coe, F L

    1984-01-01

    We have measured unidirectional transmural fluxes of oxalate and neutral sugars across rat ascending colon in vitro, under short-circuit conditions, to characterize permeability barriers selective for size and charge. Ionic oxalate appears to be transported preferentially to sodium oxalate. Mucosal addition of taurocholate (1 mM), deoxycholate (1 mM), or ricinoleate (1 mM) increased bidirectional oxalate fluxes, and the ricinoleate effects were independent of medium calcium. Bidirectional fluxes of uncharged sugar molecules fell sharply at molecular weights above 76 (molecular radius above 3 A), and oxalate transport was retarded relative to that of uncharged molecules of similar size, suggesting that there is both size and charge permselectivity. Ricinoleate increased fluxes of all neutral molecules tested but changed neither the exclusion limits nor the cation selectivity of the epithelium. Bile salts and ricinoleate increase oxalate transport, probably by making more channels available, but do not alter size and charge selectivity. PMID:6432849

  18. Subcellular Size

    PubMed Central

    Marshall, Wallace F.

    2016-01-01

    All of the same conceptual questions about size in organisms apply equally at the level of single cells. What determines the size, not only of the whole cell, but of all its parts? What ensures that subcellular components are properly proportioned relative to the whole cell? How does alteration in organelle size affect biochemical function? Answering such fundamental questions requires us to understand how the size of individual organelles and other cellular structures is determined. Knowledge of organelle biogenesis and dynamics has advanced rapidly in recent years. Does this knowledge give us enough information to formulate reasonable models for organelle size control, or are we still missing something? PMID:25957302

  19. Condensation in a two-phase pool

    SciTech Connect

    Duffey, R.B.; Hughes, E.D.

    1991-12-31

    We consider the case of vapor condensation in a liquid pool, when the heat transfer is controlled by heat losses through the walls. The analysis is based on drift flux theory for phase separation in the pool, and determines the two-phase mixture height for the pool. To our knowledge this is the first analytical treatment of this classic problem that gives an explicit result, previous work having established the result for the evaporative case. From conservation of mass and energy in a one-dimensional steady flow, together with a void relation between the liquid and vapor fluxes, we determine the increase in the mixture level from the base level of the pool. It can be seen that the thermal and hydrodynamic influences are separable. Thus, the thermal influence of the wall heat transfer appears through its effect on the condensing length L*, so that at high condensation rates the pool is all liquid, and at low rates overflows (the level swell or foaming effect). Similarly, the phase separation effect hydrodynamically determines the height via the relative velocity of the mixture to the entering flux. We examine some practical applications of this result to level swell in condensing flows, and also examine some limits in ideal cases.

  20. Condensation in a two-phase pool

    SciTech Connect

    Duffey, R.B. ); Hughes, E.D. )

    1991-01-01

    We consider the case of vapor condensation in a liquid pool, when the heat transfer is controlled by heat losses through the walls. The analysis is based on drift flux theory for phase separation in the pool, and determines the two-phase mixture height for the pool. To our knowledge this is the first analytical treatment of this classic problem that gives an explicit result, previous work having established the result for the evaporative case. From conservation of mass and energy in a one-dimensional steady flow, together with a void relation between the liquid and vapor fluxes, we determine the increase in the mixture level from the base level of the pool. It can be seen that the thermal and hydrodynamic influences are separable. Thus, the thermal influence of the wall heat transfer appears through its effect on the condensing length L*, so that at high condensation rates the pool is all liquid, and at low rates overflows (the level swell or foaming effect). Similarly, the phase separation effect hydrodynamically determines the height via the relative velocity of the mixture to the entering flux. We examine some practical applications of this result to level swell in condensing flows, and also examine some limits in ideal cases.